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May 2015

Vol. 39 No. 5

Industry Roundtable: 3D Printing Meet NASA’s Chief Technologist Energy-Based Acoustic Measurement System Photonics Tech Briefs NEW! Sensor Technology

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Welcome to your Digital Edition of NASA Tech Briefs and Photonics Tech Briefs Included in This May Edition: NASA Tech Briefs www.techbriefs.com

May 2015

Photonics Tech Briefs Vol. 39 No. 5

COMSOL News

Photonics Solutions for the Design Engineer

COMSOL NEWS

www.comsol.com

May 2015

Industry Roundtable: 3D Printing Fiber Optic Connectors — Single Step Polishing After Laser Cleaving

Meet NASA’s Chief Technologist Energy-Based Acoustic Measurement System

THE MULTIPHYSICS SIMULATION MAGAZINE

Modeling and Simulation for EVERYONE

Intelligent Photonic Multi-Sensor Solutions

Photonics Tech Briefs NEW! Sensor Technology

2015

P. 4

INNOVATIVE BUILDING DESIGN AT NEWTECNIC P. 25

The C12666MA UV-VIS micro-spectrometer is designed and built using MEMS (microelectrical-mechanical systems) technology, which allows it to be a fraction of the size of conventional spectrometers. The complete instrument measures 20.1 x 12.5 x 10.1 mm and weighs just 5 grams. To learn more, see the new products section on page 71.

Supplement to NASA Tech Briefs

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THE SWEET SIDE OF SIMULATION AT NESTLÉ P. 10

(Photo courtesy of Hamamatsu Corporation)

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Infinite Designs, One Platform with the only complete system design environment

NI LabVIEW is the only comprehensive development environment with the

LabVIEW system design software offers unrivaled hardware integration and helps you program the way you think–graphically.

unprecedented hardware integration and wide-ranging compatibility you need to meet any measurement and control application challenge. And LabVIEW is at the heart of the graphical system design approach, which uses an open platform of productive software and reconfigurable hardware to accelerate the development of your system.

>> Accelerate your system design productivity at ni.com/labview-platform

800 453 6202 ©2013 National Instruments. All rights reserved. LabVIEW, National Instruments, NI, and ni.com are trademarks of National Instruments.

Other product and company names listed are trademarks or trade names of their respective companies. 11215

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A Passion for Technology

From Crew Module water landing simulation to HPC Resource Management At Altair, we are driven to develop technology to help engineers all around the world make their dreams a reality. For the past 30 years, Altair’s software and services have been applied to analyze composite space structures, optimize the design of 3D-printed components, and simulate the motion of satellites.

Learn more at altair.com/space I N N OVAT I O N I N T E L L I G E N C E ®

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What don’t we do for NASA? While space walks and Mars landings aren’t in our portfolio yet, EMCOR Government Services does cover a vast universe of Operations & Maintenance for NASA’s Jet Propulsion Laboratory.

Below is just a sample of how we help NASA accomplish its important missions…

From power generation to quality control, we provide critical support to JPL’s space flight operations facility, in addition to diagnostic services like thermography and vibration analysis.

EMCOR Government Services supports numerous NASA programs— from the Mars Yard, SFOF and Flights Projects Center to other space flight operations that demystify our universe.

Our people also provide essential services relating to disaster response, energy and water conservation, plus all necessary subcontractor and material management.

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ONE PARTNER FOR EVERY From 3D printed prototyping to full-scale production, Stratasys Direct Manufacturing empowers designers and engineers with solutions at every stage of the design and development process. Discover our industry-leading machine capacity and full suite of traditional and advanced manufacturing services to manufacture your products better, faster and more affordably. To learn how Stratasys combined the widest breadth of technology and experience from the industry’s top service pioneers, visit S T R A T A S Y S D I R E C T . C O M

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N O

A FUL L SUI T E OF T R A DI T ION A L & A DDITI V E M A NUFACTURING

TECHNOLOGIES

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1 - 8 8 8 - 3 11 -1 0 17 INFO@STR ATA SYSDIRECT.COM

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May 2015 • Vol. 39 No. 5

Contents

Features

24

12

Products of Tomorrow

16

Industry Roundtable: 3D Printing

24

Application Briefs

80

NASA Spinoff: UV Radiation Research Keeps Sun Worshipers Safe

Solutions 26

Technology Focus: Test & Measurement

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Quantitative Analysis of Failure Mode in Adhesively Bonded Test Specimens Energy-Based Acoustic Measurement System for Rocket Noise Mass Gauging Demonstrator for Any Gravitational Conditions Multiport Hat Coupler for Electronically Steerable Antenna Testing Neutron Spectrometer for Inner Radiation Belt Studies High-Energy Instrumentation for Small Satellite Platforms Variable Acceleration Force Calibration System A Synthetic Quadrature Phase Detector/Demodulator for Fourier Transform Spectrometers Device for Direct Measurement of the Diffusivity and Molecular Release Through Membranes and Filters

26 28 30 32 33 34 35 36

38

Manufacturing & Prototyping

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Increased Alignment in Carbon Nanotube Growth Process to Fabricate Specific Sized Monodisperse Polystyrene Microparticles Atmospheric Pressure Plasma-Based Fabrication of Printable Electronics and Functional Coatings Passive Destructive Interference Acoustic Liner for a Turbofan Engine Using Additive Manufacturing

39 40

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Mechanical & Fluid Systems

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Diminutive Assembly for Nanosatellite deploYables (DANY) Miniature Release Mechanism Quantitative Real-Time Flow Visualization Technique Thin-Film Evaporative Cooling for Side-Pumped Lasers MEMS Micro-Translation Stage with Large Linear Travel Capability Planar and Non-Planar Multi-Bifurcating Stacked Radial Diffusing Valve Cages

42 43 44 44

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Aeronautics

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Real-Time Aerodynamic Parameter Estimation Without Airflow Angle Measurements Method for Improving Control Systems with Normalized Adaptation

by Optimal Control Modification Airborne Coordinated Conflict Resolution and Detection (ACCoRD) Framework Integrated Pitot Health Monitoring System NASA Aircraft Management Information System (NAMIS) Sector 33 App

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Health, Medicine & Biotechnology

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Retinal Light Processing Using Carbon Nanotubes Provision of Carbon Nanotube Buckypaper Cages for Immune Shielding of Cells, Tissues, and Medical Devices Rapid Polymer Sequencer High-Density, Homogenous Bacterial Spore Distributions on Test Surfaces

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51 52

74

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Departments 10 14 78 79

UpFront Who’s Who at NASA NASA’s Technology Transfer Office Advertisers Index

New for Design Engineers 74 75

Product Focus: Materials & Coatings New Products/Software

COMSOL NEWS

www.comsol.com

2015

THE MULTIPHYSICS SIMULATION MAGAZINE

Modeling and Simulation for EVERYONE

Special Advertising Supplement 1a – 40a COMSOL News

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INNOVATIVE BUILDING DESIGN AT NEWTECNIC P. 25 THE SWEET SIDE OF SIMULATION AT NESTLÉ P. 10

(Solutions continued on page 8)

6

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MATLAB speaks Raspberry Pi so you don’t have to

You can design, build, test and run a system– on Arduino, Raspberry Pi, LEGO and more– without writing traditional code.

Download free MATLAB and Simulink hardware support packages at hardware.mathworks.com

©2015 The MathWorks, Inc

®

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Contents 53 53

Team Game and Simulation Control CRP Aptamers to Bone-Specific Alkaline Phosphatase (BAP)

Product of the Month

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Communications

54 54 55

VCSEL Laser Array for Communications Providing a Real-Time Audible Message to a Pilot Pass Plan Formatter (PPF) for Earth Sciences Ground Support System Integrated Tool Archives, Extracts, and Analyzes Spacecraft Housekeeping Telemetry Data (GMSEC R3.0) Low-Noise Analog APDs with Impact Ionization Engineering and Negative Feedback Method to Improve Wireless System Communication Coverage in a Bended Tunnel Environment

Sensirion (Westlake Village, CA) introduced a gas sensor based on multi-pixel technology that detects and distinguishes between different gases.

55 56 57

58

Information Technology & Software

58 58 59 59 60

Space Weather Database of Notifications, Knowledge, Information – DONKI Core Flight System (cFS) Software Bus Network Application Version 1.0 STARS Finite Element Multidisciplinary Analysis Computer Program Hazards Analysis Management Tool Developing Web and Mobile Applications Integrated with Systems Utilizing the Object Management Group’s Data Distribution Service Synthetic Imaging Maneuver Optimization – SIMO

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Photonics Solutions for the Design Engineer May 2015

Fiber Optic Connectors — Single Step Polishing After Laser Cleaving Intelligent Photonic Multi-Sensor Solutions

The C12666MA UV-VIS micro-spectrometer is designed and built using MEMS (microelectrical-mechanical systems) technology, which allows it to be a fraction of the size of conventional spectrometers. The complete instrument measures 20.1 x 12.5 x 10.1 mm and weighs just 5 grams. To learn more, see the new products section on page 71.

Supplement to NASA Tech Briefs

(Photo courtesy of Hamamatsu Corporation)

63

Photonics Tech Briefs

64

Fiber Optic Connectors: Single Step Polishing After Laser Cleaving Intelligent Photonic Multi-Sensor Solutions New Products

68 71

This document was prepared under the sponsorship of the National Aeronautics and Space Administration. Neither Associated Business Publications Co., Ltd. nor the United States Government nor any person acting on behalf of the United States Government assumes any liability resulting from the use of the information contained in this document, or warrants that such use will be free from privately owned rights. The U.S. Government does not endorse any commercial product, process, or activity identified in this publication.

74 On the cover 3D printing technology continues to advance, transforming most aspects of our lives. Designers and engineers find new applications for 3D printing every day, including the cellphone cases pictured on our cover, which were created using a Projet 4500 plastic printer from 3D Systems (Rock Hill, SC). Find out more about the future of 3D printing from experts in the field in our Industry Roundtable beginning on page 16.

(Image courtesy of 3D Systems)

Permissions: Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by Associated Business Publications, provided that the flat fee of $3.00 per copy be paid directly to the Copyright Clearance Center (222 Rose Wood Dr., Danvers, MA 01923). For those organizations that have been granted a photocopy license by CCC, a separate system of payment has been arranged. The fee code for users of the Transactional Reporting Service is: ISSN 0145-319X194 $3.00+ .00

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Together, we can build a leaner, greener machine.

Save fuel, the environment, and your bottom line with Parker RunWise® Advanced Series Hybrid Drives.

Parker’s new RunWise Advanced Series Hybrid Drive system for Class-8 refuse trucks delivers fuel economy and environmental performance unlike any other hybrid. By combining hydrostatic operation for city driving, mechanical drive for the highway, and best-in-class brake energy recovery, RunWise is capable of reducing fuel consumption up to 50% and can lower carbon emissions up to 55 tons per year. Add to that the benefit of extending brake replacement to once in the life of the truck and reducing overall engine wear and maintenance costs, and you have a hybrid that delivers the kind of returns you demand from your vehicle fleet. How does it drive? Smooth and quick launch speeds help drivers cover routes faster, maximizing productivity and profitability. To learn more about how Parker can benefit your bottom line and the communities you serve, visit parkerhybrid.parker.com.

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Technical Notes

The Avago Advantage Smart Gate Drive Optocoupler with Integrated Flyback Controller Insulation Transformer Feedback Controller

Introduction

HCPL-3120 Controller

The new ACPL-302J is a smart gate drive optocoupler that improves isolated power supply and simplifies gate drive design. The ACPL-302J features an integrated flyback controller for DC-DC converters and a full set of fail-safe IGBT diagnostics, protection, and fault reporting, providing a complete cost-effective gate drive solution (Figure 1). With a 2.5A railto-rail output, the device is ideal for driving IGBTs and power MOSFETs in industrial power inverters and motor drives. The end result is an easy-touse, compact, and affordable IGBT gate drive optocoupler solution.

SW

VEE2

Desat Detection

Blanking Current Source

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IGBT or Power MOSFET

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Soft Shut Down

Miniature Isolation Amplifier

Figure 2: Basic gate driver optocoupler with isolated high side power supply to drive and protect IGBT in motor drives and inverter.

Logic R S Control

LED2+ UVLO

Input Driver

VE DESAT Over Output Current Driver

VEE1 ANODE CATHODE

Motor / Grid

Bipolar Buffer

VCC2

OSC

FAULT

Inverter

Motor Drives / Inverter

Functional Diagram

VCC1 COMP UVLO

Feedback

Isolated High Side Power Supply

VO SSD/ CLAMP

SSD Cntrl Miller Cntrl

VEE2

Figure 1: Functional diagram of ACPL-302J gate drive optocoupler

In a centralized power supply system, the isolated high side power supply powers six gate drivers using a single large transformer. The transformer houses four secondary windings, three for the floating supplies for each phase of the top gate drivers and a common supply for the bottom gate drivers (Figure 3). In addition to the large transformer are large capacitors for filtering and large transistors for the primary winding switching are needed. These large devices impact real estate size and height.

Also a centralized supply has inherent problems like electromagnetic interference (EMI) and noise coupling between IGBT channels due to the longer traces required to reach all six gate drivers.

The Centralized Power Supply

Single switch deliver all powers, high EMI noise Long traces, more noise emission

Gate drive optocouplers are used to provide high voltage reinforced galvanic insulation and deliver high output current to switch the IGBTs in motor drives or inverters. Discrete components like voltage comparators and transistor switches are used to protect expensive IGBTs during short circuit faults while digital optocouplers are used to provide isolated feedback. Avago Technologies has integrated these discrete components into the smart gate drive optocouplers like the ACPL-302J. An isolated high-side power supply is required to provide static and switching power source for gate drivers and some miniature isolation amplifiers for current sensing (Figure 2). The common design uses a centralized power supply topology made up of a bulky 3-phase transformer and feedback controller to achieve a stable 3-phase DC source for the isolated high-side power supply.

Large transformer, capacitors and switch

Figure 3: The centralized power supply topology.

Your Imagination, Our Innovation

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The Avago Advantage Technical Notes The Distributed Power Supply Insulation ACPL-302J

POWER, ISOLATE, DRIVE (Fault & UVLO)

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FEEDBACK, PROTECT

IGBT or Power MOSFET

ACPL-302J

ACPL-302J

IGBT

IGBT

ACPL-302J

Motor Drives / Inverter

IGBT

IGBT

Figure 5: ACPL-302J, 2.5A gate drive optocoupler with integrated flyback controller, active miller clamp, DESAT and UVLO detection.

Summary By integrating the flyback controller, the ACPL-302J device allows fewer discrete components and smaller transformers and capacitors to be placed next to the device, thus reducing the overall footprint of the design and minimizing electromagnetic interference (EMI) and noise coupling between IGBT channels. By reducing these elements of the design, there is a notable cost savings the designer can realize.

Smaller transformers and capacitors

Figure 4: The distributed power supply topology.

The Centralized Power Supply

The Distributed Power Supply with ACPL-302J

Big transistor switch

Big capacitors

Motor / Grid

Controller

Miniature Isolation Amplifyer

ACPL-302J

ACPL-302J ACPL-302J

IGBT

Inverter

FLYBACK CONTROLLER

Transformer placed close to the load emitting less and rejecting more EMI noise

IGBT

Isolated High Side Power Supply

Transformer

+ –

The ACPL-302J device was developed to improve isolated power supplies and simplify gate drive design. The device is optimized for distributed power supply topology (Figure 4 and 5). It is a 2.5A rail-to-rail smart gate drive optocoupler with an integrated flyback controller for DC-DC converters. By integrating the flyback controller, the ACPL-302J enables integration of smaller high-efficiency transformers to be placed next to the device (Figure 6). As a result, the designer can reduce the overall footprint, minimizing electromagnetic interference (EMI) and noise coupling between IGBT channels. With a smaller transformer, the primary winding switching transistor is integrated in the ACPL-302J and smaller capacitors can be used for filtering.

Integrated transistor in ACPL-302J

Small capacitors

Big transformer

Small transformer

Figure 6: The board level view of the distributed power supply topology using ACPL-302J and benefits.

Contact us for your design needs at:

www.avagotech.com/smartgatedrive

Avago, Avago Technologies and the Avago logo are trademarks of Avago Technologies in the United States and other countries. All other trademarks are the property of their respective companies.

Data subject to change. Copyright © 2014 Avago Technologies AV00-0304EN 12/19/14 Free Info at http://info.hotims.com/55589-900

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UP FRONT Editor’s Choice

Linda Bell Editorial Director

A Very Special Delivery

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MEMS micro-translation stage features large linear travel capability, and can translate across long distances using just three-phase power. Essentially a linear motor built from a silicon base using microfabrication techniques, the device can be as small as 100 mm and can house lenses, mirrors, absorbers, and sampling compartments for applications in optics, communications, sensors, and biotechnology. Find out more on page 44.

NASA Drives Future Discoveries A new NASA-designed information knowledge base, Physical Science Informatics consists of critical information on NASA’s physical science research. It puts information on past, current, and future International Space Station physical science investigations in one digital repository, making it easy for investigators to find out what’s been done so far in research areas and devise where to go next. Researchers interested in obtaining access should visit the Physical Science Informatics Web site at http://psi.nasa.gov.

Next Month in NTB The June issue will include special coverage on batteries and power. Find out what engineers need to know to choose the proper battery for a variety of environments and conditions.

Also featured in the June issue will be a technology focus on the latest innovations in data acquisition. You’ll also learn how camera calibration techniques developed by NASA for monitoring propulsion tests are being used to improve the quality of satellite images.

Recently, engineers at NASA’s Marshall Space Flight Center in Alabama unboxed some special cargo from the International Space Station: the first items manufactured in space with a 3D printer.

The items were manufactured as part of the 3-D Printing in Zero-G Technology Demonstration on the ISS to show that additive manufacturing can make a variety of parts and tools in space. These early inThe first item manufactured in space with a space 3D printing demonstrations are the 3D printer was a wrench. The parts are profirst steps toward realizing a print-ontected in sealed bags until testing begins.

(NASA/MSFC/Emmett Given) demand “machine shop” for long-duration missions and sustaining human exploration of other planets, where there is extremely limited availability of Earth-based resupply and logistics support.

The parts were returned to Earth in February on the SpaceX Dragon, and were then delivered to Marshall where the testing to compare the ground controls to the flight parts will be conducted. Before the printer was launched to the space station, it made an identical set of parts. Now, materials engineers will put both the space samples and ground control samples literally under a microscope and through a series of tests to scan for differences in the objects.

Watch a video of the cargo unveiling on Tech Briefs TV at www.techbriefs.com/ tv/3D-delivery.

Freezing for Survival

The James Webb Space Telescope (JWST) will have to survive the mechanically stressing conditions of launch, and the telescope and scientific instruments will have to survive the thermal shrinkage that occurs when cooling down from room temperature to the cryogenic temperatures at which they operate. This is a significant engineering challenge because the JWST and its instruments operate at extremely cold temperatures, but they are built at room temperature.

Johnson Space Center’s Chamber A is a thermalvacuum test facility famous for testing the Apollo spacecraft. It has undergone a major reconstruction effort in support of the JWST test program. The chamber includes an ultra-clean, hydrocarbon-free, high vacuum pumping system, with the ability to simulate the extremely low temperatures of deep space (35K) within a 45 x 80-foot-tall shroud volThis photo was captured from ume. The chamber systems will also be able to main- outside Chamber A. (NASA/Chris tain Class 10,000 cleanroom conditions for ambient Gunn) operations.

Learn more about the instruments, science, and testing of the JWST at http://jwst.nasa.gov.

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The technologies NASA develops don’t just blast off into space. They also improve our lives here on Earth.

Life-saving search-and-rescue tools, implantable medical devices, advances in commercial aircraft safety, increased accuracy in weather forecasting, and the miniature cameras in our cellphones are just some of the examples of NASA-developed technology used in products today.

This column presents technologies that have applications in commercial areas, possibly creating the products of tomorrow. If you are interested in licensing the technologies described here, use the contact information provided. To learn about more available technologies, visit the NASA Technology Transfer Portal at http://technology.nasa.gov.

Products of

Tomorrow ►

In-Situ Health Monitoring of Piezoelectric Sensors

►

With this monitoring system developed by Stennis Space Center, degraded sensor performance can be quickly and economically identified. It evaluates installed piezoelectric sensors without requiring physical contact with, or removing them from, their mounted locations. Because it is not necessary to remove the device, data that reflects the device’s specific physical configuration is retained, and devices that are physically inaccessible can still be tested. The system can detect changes within the entire sensor and sensor housing.

Method for Ultraminiature Fiber Light Source

Miniature incandescent lamps have been invented to satisfy a need for compact, rapidresponse, rugged, broadband, power-efficient, fiber-optic-coupled light sources for diverse purposes that could include calibrating spectrometers, interrogating optical sensors, spot illumination, and spot heating. Developed at Glenn Research Center, these lamps include a spiral filament mounted within a ceramic package that normally is used to house an integrated circuit chip. The package is closed with a window that normally is used in ultraviolet illumination to erase volatile electronic memories.

Contact: Stennis Office of the Chief Technologist Phone: 228-688-1929 E-mail: ssc-technology@nasa.gov

Contact: Glenn Technology Transfer Office Phone: 216-433-3484 E-mail: ttp@grc.nasa.gov http://technology.grc.nasa.gov

►

Magnetoresistive Flux Focusing Eddy Current Flaw Detection

NASA Langley has developed a new nondestructive evaluation probe to detect small fatigue cracks prior to the onset of widespread fatigue damage. The detection of deeply buried fatigue cracks in thick multilayer structures like airplane wings continues to be a challenge for the nondestructive evaluation community. This new technology leverages the low-frequency magnetic field sensitivity of giant magnetoresistive (GMR) sensors to identify subsurface cracks up to 1 cm deep.

Contact: Langley Technology Transfer Office Phone: 757-864-5704 E-mail: LARC-DL-technologygateway@nasa.gov

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Rapid Manufacturing with a Polite Disregard for Tradition Tech-driven injection molding, CNC machining and 3D printing for those who need parts tomorrow

Proto Labs uses proprietary software and a massive compute cluster to accelerate manufacturing of prototypes and production parts for every industry.

Got a project? Get 1 to 10,000+ plastic, metal or liquid silicone rubber parts in as fast as 1 day.

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Who’s Who at NASA Dr. David W. Miller, Chief Technologist, NASA Headquarters, Washington, DC

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r. David Miller began his term as NASA’s Chief Technologist on March 17, 2014. He currently serves as the Agency’s principal advisor and advocate on NASA technology policy and programs. Miller, a professor at the Massachusetts Institute of Technology, previously worked with a range of NASA programs, including the space shuttle, the International Space Station, and the CubeSat Launch Initiative.

NASA Tech Briefs: What does the Chief Technologist do?

Dr. David Miller: The Chief Technologist advocates for technology investment at NASA. I engage with the external community and try to best understand what’s happening outside of NASA in the world of technology. I’m also the lead in helping to set up challenges and prizes, and engage the broader community. I advise the Administrator about all things technology.

NTB: How does NASA prioritize their investment in technologies?

Dr. Miller: The budget actually tells you what you can afford to do. The way we think about it is that roadmaps are what we could do, prioritization is what we should do, and funding is what we will do.

There are obviously a lot of scientific missions at NASA. We think about the technology we need to support those missions, but we also have an important goal in helping to support the broader communities out there — the commercial space sector as well as the commercial aeronautics sector. We try to think about the core technologies that “lift all ships,” and that’s what we prioritize.

NTB: What are some high-priority technology areas?

Dr. Miller: There are a number of exciting areas, such as solar electric propulsion, which is a way to efficiently move cargo through space. That’s important for Mars missions, or for controlling satellites in geosynchronous orbit. The technology has a very specific NASA benefit, but also supports a lot of programs outside of NASA. Another area is laser communication. Traditionally, we have done telecommunications using radio waves, but when you move up to the frequency of light, you have much higher bandwidth and data rate. Recently, on the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission to the Moon, we were able to send back, via laser, large volumes of data very quickly.

We’re thinking about how we can reduce the carbon input to the atmosphere. Commercial airliners fly up in the strato14

sphere, and the carbon that is put out has a long latency time at that level. Also of interest is low-boom supersonics. Being able to start supersonic flight over the continent is an interesting thought, but we really have to suppress the sonic booms that happen. Another area is highly efficient transport. Fuel is getting more expensive, and if we can fly with less fuel, that’s a dramatic benefit.

NTB: Why is it important for NASA to license technologies to industries?

Dr. Miller: Licensing technologies helps to make those industries stronger, and helps to get a dual use of the technology investment that NASA has made. There are a number of different investments we make that can be spun-off to the nonaerospace sector. In fact, a lot of smartphones use cameras that have been developed through space technology investments.

NASA operates on taxpayer dollars, and it’s important to maximize the benefit to the taxpayer.

“Spin in” is an important concept. Our missions are expensive. We want to make sure that we don’t duplicate efforts happening elsewhere. If there are other industries or other government agencies that are developing technologies that we can use, it’s a great idea to leverage that.

NTB: What are some of the challenges and prizes your office promotes?

Dr. Miller: It’s important that NASA’s mission is not just NASA’s mission alone. The Asteroid Grand Challenge, for example, gets the community to help us think about how to defend the planet. You can take a look at data sets we make available and try to find asteroids. It’s a vast amount of data, and we need extra eyes on it. NASA Solve (nasa.gov/solve) is a one-stop shopping portal for all of those challenges.

NTB: What are your goals for this year?

Dr. Miller: I have some insight on how to make the International Space Station more accommodating to users, particularly those who want to test technology.

I have a love for human spaceflight. Trying to help NASA address the challenges associated with the human journey to Mars is a very exciting one. Mars is a much more difficult step than getting to the Moon, and the way you might get there is not as straight a path as you might think.

It’s always easy to think about what we ought to be working on — it’s difficult to say what we should not be working on. It’s a tough decision. When you have precious resources that you can spend, you really have to pick and choose.

To read a full transcript of the interview, or listen to a downloadable podcast, visit www.techbriefs.com/podcast. Visit the Office of the Chief Technologist at www.nasa.gov to download NASA technology roadmaps, and visit NASA’s TechPort at http://techport.nasa.gov to see what NASA is working on in various areas, and how to learn more.

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Industry Roundtable: 3D Printing

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t seems that every day, designers and engineers are finding exciting new applications for 3D printing, from creating custom prostheses to making tools used for repairs on the International Space Station. 3D printing is considered a revolutionary technology that can transform our lives. But what are the real benefits — and the real consequences — of such a drastic change in manufacturing?

NASA Tech Briefs recently spoke with experts in various aspects of 3D printing to get their answers to this question and others. Our panel members are Buddy Byrum, Vice President of Product Management for 3D Systems; Jon Cobb, Executive Vice President of Corporate Affairs for Stratasys; Max Lobovsky, Founder of Formlabs; Dr. Conor MacCormack, Co-Founder and CEO of Mcor Technologies; and Alfonso Perez, Co-Founder and CEO of New Valence Robotics Corporation.

NASA Tech Briefs: 3D printing is infiltrating every aspect of our work and personal lives. Many are supporting the idea of a “3D printer for everyone.” What are the benefits and consequences of this idea?

Max Lobovsky: 3D printing is a tool for creating and realizing new ideas, and we find it is most relevant and powerful in the hands of engineers and designers. It is a revolutionary technology, but it is still a tool — it’s misleading to frame the technology as everything for everybody. To have a 3D printer for everyone, you have to ask how we can develop experiences and platforms that allow everyone to create.

Buddy Byrum: The question is not if everybody will have a 3D printer, but how everybody will integrate 3D printing into their lives. 3D printing is a revolutionary technology that has the ability to transform and enhance the ways in which we do nearly everything in our lives — how we work, how we play, how we create, how we dress, how we learn, and even how we eat. Remember that 3D printing is an exponential technology, and it is developing at an accelerating rate. And exponential technologies often outpace even our own imaginations. As more and more people rely on 3D printing in their daily lives, we will see powerful and impactful new applications emerge that take this technology farther than anything we can envision now.

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“Manufacturers are constantly looking at new and different ways to make their products better, faster, and cheaper to produce. Thousands of manufacturers are looking at 3D printing not because it is new, but because they are looking to solve one of these issues.”

Jon Cobb, Stratasys

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3D Printing Jon Cobb: The concept of 3D printing has been a hot topic for discussion since the introduction of the “Maker Movement” several years ago. The capabilities of 3D printing allow individuals to bring their creative concepts to reality. 3D printing can empower people with the ability to design, modify, and eventually print a part or product. There are downsides to 3D printing for everyone. These can include product safety and part quality because certification is lacking when a part is produced away from a manufacturer’s quality procedures.

Conor MacCormack: We live in exciting times. We’ll look back on this time in history and remember it as the start of a revolution — a revolution that will provide a 3D printer for everyone. There is hype, but the promise of 3D printing is as big as 2D printing. If we can take the current hype and convert it to a technology with a purpose, the possibilities are endless. I see the biggest benefit of 3D printing to be the democratization of innovation. Before this, the biggest companies in the world felt like they were the only ones able to innovate. However, 3D printing now puts that power in everyone’s hands. As long as the technology is sustainable, I don’t see any down side.

Alfonso Perez: The immediate benefit of the “3D printer for everyone” concept is just-in-time delivery of customized goods direct to the end user. However, it is important to note that with the good comes the bad. There are two primary drawbacks. First is that easy, cost-effective access to 3D printers in the home will lead to excessive use of the technology, resulting in exponential increases in plastics waste. Second, consumers do not realize that 3D printers are complex pieces of manufacturing equipment and must be treated as such.

NTB: There have been so-called “killer apps” in many industries that define the value of a technology. What are the killer apps in 3D printing, and what role do they play?

MacCormack: You could argue that there is no single killer app in 3D printing, but instead many killer apps, with new ones appearing each day. In some ways, they may seem like just another application for 3D printing, but fundamentally, they

“Most of the work in 3D printing materials has been trying to take traditional manufacturing materials and 3D print them. As the technology proliferates, we’ll start to develop materials with properties that don’t exist today, and that’s when things get really exciting.”

Max Lobovsky, Formlabs

really are solving a problem and providing a profound daily benefit. For example, the killer app of doctors 3D printing maxillofacial surgical guides to vastly improve patient outcomes is immensely different from that of average consumers who create realistic 3D printed photos of family and friends for this year’s holiday gifts. These apps are making a real difference everyday in the lives of the people who use them. So I rather think of this as not a killer app, but a suite of killer apps. Without killer apps, you have a technology that nobody can use or needs. As the technology evolves, the apps will be drawn to the technology.

Cobb: We see two killer apps emerging; the first is manufacturing. This does not necessarily mean a wholesale change in manufacturing, but the integration of manufacturing into the mainstream for a wide variety of manufacturers. This implementation will take place at different times and locations within the manufacturing process. It can range from printing very simple parts for a period of time, to full-scale tooling, to a complete overhaul in a design that enables a new way of manufacturing. The second killer app is in the medical and dental field.

Digital dentistry, combined with 3D printing, is having a significant impact. And, there are numerous documented cases on custom prosthetics.

“3D printing allows us to fundamentally rethink design and manufacturing. It allows Perez: The killer apps in 3D printing us to create parts with infinite complexity have yet to be invented. The future is — optimized for performance, not manubright for design for 3D printing. Once a facturability. 3D printing is a game-changer, toolkit exists for engineers to use to and the question for most businesses is design for 3D printing, they will be able whether they use these new capabilities to to specifically “program” a physical proddisrupt their industry, or whether they get uct for all of the required characteristics. disrupted.”

Imagine specifically controlling the mechanical, thermal, electrical, and material properties of a product from Buddy Byrum, 3D Systems the inside out — no conventional manufacturing technology can do that.

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3D Printing Continued materials innovation will unlock bold new applications in the years to come, and allow us to reimagine what is possible with 3D printing.

MacCormack: I see materials broken up into two categories.

First, there will be materials that more closely represent realworld materials used in everyday life. Second, 3D printing also enables new types of materials that have never been possible before with variable properties in different locations of the same part. Materials used for prototyp“Once a toolkit exists for engineers to ing will have to be environmentally use to design for 3D printing, they will friendly, sustainable, and biodegradable. be able to specifically ‘program’ a physical product for all of the required characPerez: Materials exist in many broad teristics. Imagine specifically controlling categories: metals, thermoplastics, phothe mechanical, thermal, electrical, and topolymer resins, biomaterials, conducmaterial properties of a product from the tive materials, and ceramics. My instincts inside out. No conventional manufacturas a mechanical and manufacturing engiing technology can do that.” neer tell me that the metals space will experience the most rapid adoption and Alfonso Perez, innovation. The primary applications will Byrum: 3D printing refers to a be in complex electromechanical systems New Valence Robotics broad and interrelated ecosyswhere weight matters because of rising tem of 3D products and services, fuel costs — spacecraft, aircraft, and and we believe that every business automotive. Naturally, medical comes to and every individual will choose to engage with this ecosystem mind, but due to lack of process understanding and high govdifferently. Some will use production printers to manufacture ernment oversight, I believe medical comes in a close second. complex, end-use parts in metals or high-performance plastics; others might use 3D printing to develop functional part test Lobovsky: Most of the work to date in 3D printing materials models, prototypes, or concept models. Doctors, on the other has been trying to take more materials from those used in trahand, will use 3D software, devices, and printers to virtually preditional manufacturing, and allow them to be 3D printed. pare, create instruments for, and execute a personalized surgical This is important work and it will continue, especially with a procedure from patient-specific data. There are many ways that lot of progress in high-performance metals and plastics. As the 3D printing will — and in most cases, already does — impact technology proliferates, we’ll start to develop materials with everything in our lives. properties that don’t exist today, and that’s when things get really exciting.

Lobovsky: One area that I think has yet to be really understood has to do with applications that change the way people design and create. 3D printing can be a powerful tool that people use directly, not through a service bureau or prototyping shop. With this lens, 3D printing eliminates much of the process of development, enabling people to make things much faster and much cheaper. Similar to the spread of desktop software, when more people have direct access to this technology, it creates new possibilities for new, powerful ideas.

NTB: There are more and more functional materials being offered for 3D printers, and there is a demand for material integration. What are some of the new materials we can expect to see being used by 3D printers, and what will their primary applications be initially?

“I see the biggest benefit of 3D printByrum: Right now, we can print in more than 120 ing to be the democratization of innomaterials, from metals to edibles, and that number vation. Before 3D printing, the biggest continues to rise. The expansion of material choices companies in the world felt like they and capabilities is fueling some of the most advanced were the only ones able to innovate. applications for 3D printing. The ability to directly 3D printing now puts that power in print in metals allows us to produce flight-ready aeroeveryone’s hands.” space parts and under-hood automotive parts, for example, as well as highly intricate medical and dental Dr. Conor MacCormack, devices. At the same time, new elastomeric and heatMcor Technologies and chemical-resistant materials allow engineers to print parts for the most rigorous functional tests.

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3D Printing NTB: What do you recommend to a prospective customer who needs to identify or justify current part manufacturing technology cost versus the cost of a 3D printer?

MacCormack: It is not simply comparing manufacturing costs versus the cost of the printer; it is the cost savings your business can experience by making parts early in the design cycle. If the final design of the part is known at the very first pass (which is highly unlikely), it is hard to see how conventional machining could be beaten. But we don’t live in this world. Instead, numerous changes are required through iteration, and this is where 3D printing comes in and scores big bucks. In the near term, it is very possible that traditional manufacturing methods and 3D printing will work hand-in-hand. 3D printing will be another tool in the toolbox.

Perez: First of all, the customer needs to think additive manufacturing, not rapid prototyping. This is a crucial distinction to make; additive manufacturing implies that the 3D printing process will be used in a manufacturing system to make a finished good.

Depending on the 3D printing system, the customer needs to consider energy costs, machine cost, material cost, and operator cost.

Byrum: The decision to embrace 3D printing is not a case of either/or, but rather both/and. There are certainly some parts for which traditional manufacturing is sufficient. With the availability of 24/7 cloud printing services, companies don’t even need to have a 3D printer to reap the benefits of 3D printing.

However, the big idea about 3D printing is that it allows us to fundamentally rethink design and manufacturing. It allows us to create parts with infinite complexity, optimized for performance, not manufacturability. 3D printing is a game-changer, and the question for most businesses is whether they choose to use these new capabilities to disrupt their industry, or whether they get disrupted.

Lobovsky: A 3D printer is a powerful tool, but it is a tool.

There will be times it isn’t appropriate for the challenge. But in today’s fast-moving world, if you need to shorten development cycles by realizing your ideas fast and cheaper, it is an essential technology. For creators inventing a world that does not yet exist, it can be revolutionary.

Cobb: Manufacturers are constantly looking at new and different ways to make their products better, faster, and cheaper to produce. 3D printing is being looked at today by thousands of manufacturers not because it is new, but because they are trying to meet these goals. 3D printing allows a manufacturer to go directly from CAD design to part. The savings in time-tomarket or eliminating the cost of the tool can be substantially beneficial to a manufacturer.

RESOURCES 3D Systems www.3dsystems.com

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APPLICATION BRIEFS 3D-Printed Functional Antenna Arrays Operate on Exterior of COSMIC-2 Satellites FDM® (Fused Deposition Modeling™) technology and ULTEM 9085 thermoplastic Stratasys Direct Manufacturing (RedEye, Solid Concepts, and Harvest Technologies) Eden Prairie, MN 866-882-6934 www.redeyeondemand.com

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n 2006, a satellite mission called the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC1) was put into orbit. The purpose of the instrument was to collect global ionospheric and atmospheric data of temperature, moisture, and pressure, including hard-to-sample areas such as above oceans and polar regions. The project was led by the University Corporation for Atmospheric Research (UCAR), a consortium of more than 70 research universities in the US, and Meteorological Society of the Republic of China (Taiwan). Since its inception, the COSMIC-1 project has contributed to a wide range of scientific investigations and improvements in weather forecasting.

Due to COSMIC-1’s success, US agencies and Taiwan have been working on a follow-up project called FORMOSAT7/COSMIC-2 that will launch six satellites into orbit in late 2016 and another six in 2018. NASA’s Jet Propulsion Laboratory (JPL) has developed satellite technology to capture a revolutionary amount of radio occultation data from Global Positioning System (GPS) and Russian GLONASS satellites that will benefit weather prediction models and research for years to come.

COSMIC-2 design and development began in 2011 at JPL. Critical components of the COSMIC-2 design are the actively steered, multi-beam, high-gain phased antenna arrays capable of receiving the radio occultation soundings from space.

Traditionally, only large projects could afford custom antennas. COSMIC-2 was a medium-sized project that required 30

Rendering of a FORMOSAT-7/COSMIC-2 satellite. (NSPO, NOAA, NASA/JPL, UCAR, SSTL)

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antennas, so minimizing manufacturing costs and assembly time was essential.

A standard antenna array support design is traditionally machined out of astroquartz, an advanced composite material certified for space. The team knew building custom antenna arrays out of astroquartz would be time-consuming and expensive because of overall manufacturing process costs (vacuum forming over a custom mold) and lack of adjustability (copper sheets are permanently glued between layers of astroquartz).

The custom antenna design also contained complex geometries that would be difficult to machine and require multiple manufacturing, assembly, and secondary operations, causing launch delays. JPL turned to additive manufacturing technology to prototype and produce the antenna arrays.

The manufacturing technology chosen to build accurate, lightweight parts while maintaining the strength and load requirements for launch conditions was Stratasys’ Fused Deposition Modeling (FDM). FDM could produce this complete structure as a single, ready-for-assembly piece. This would enable quick production of several prototypes for functional testing and the flight models for final spacecraft integration all at a low cost. FDM can also build in ULTEM 9085, a highstrength, engineering-grade thermoplastic with excellent radio frequency and structural properties, high temperature and chemical resistance, and could be qualified for spaceflight.

Instead of purchasing an FDM machine to produce the parts internally, JPL turned to Stratasys Direct Manufacturing, which has the largest FDM capacity in the world, and project engineering experts who have experience with the aerospace industry and its requirements.

The antenna array support structures were optimized and patented for the FDM process. All shapes were designed with an “overhead angle” of 45 degrees at most to avoid using breakaway ULTEM support material during the build. JPL was also able to combine multiple components into one part, which minimized technician assembly and dimensions verification time and cost.

Although FDM ULTEM 9085 has been tested for in-flight components, it had never been used on the exterior of an aircraft, let alone in space. Therefore, in addition to standard

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functional testing, FDM ULTEM 9085 and the parts had to go through further testing in order to meet NASA class B/B1 flight hardware requirement, including susceptibility to UV radiation and atomic oxygen, and outgassing. Other testing included thermal properties tests; in particular, compatibility with aluminum panels. Aluminum has a slightly different coefficient of thermal expansion than non-glass-filled ULTEM. Vibration/ acoustic loads standard to the launch rocket were tested, as well as compatibility with S13G high-emissivity protective white paint and associated primer.

Over 13 months, RedEye produced 30 antenna array structures for form, fit, and function testing. Throughout each design revision, RedEye’s project engineering team worked closely with JPL to process their STL files to ensure the parts met exact tolerances, and to minimize secondary operations. RedEye’s finishing department deburred the parts where needed, stamped each with an identification number, and included a material test coupon. They also reamed holes for fasteners that attach to the aluminum honeycomb panel and the small channels throughout the cones to the precise conducting wire diameter.

“Not only did NASA JPL save time and money by producing these antenna arrays with FDM, they validated the technology and material for the exterior of a spacecraft, paving the way for future flight projects,” said Joel Smith, strategic account manager for aerospace and defense at RedEye. “This is a great example of an innovative organization pushing 3D printing to the next level and changing the way things are designed.”

As of last year, the COSMIC-2 radio occultation antennas and FDM ULTEM 9085 were at NASA Technology Readiness Level 6 (TRL-6). RedEye was able to successfully enter the JPL Approved Supplier List, and delivered 30 complete antennas for final testing and integration. The FORMOSAT7/COSMIC-2 mission will operate exterior, functional 3D printed parts in space for the first time in history.

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Technology Focus: Test & Measurement Quantitative Analysis of Failure Mode in Adhesively Bonded Test Specimens A fluorescence visualization technique is used.

Langley Research Center, Hampton, Virginia

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fter adhesively bonded mechanical test specimens have been tested to failure, the failure mode must be interpreted and quantified. Areas of the adherent that are bare (no residual adhesive remains) have undergone adhesive failure. The remainder of the surface has undergone cohesive failure.

The ability to distinguish and accurately quantify the relative amounts of cohesive and adhesive failure on a failed bonding surface is of tremendous importance in the field of mechanical testing, and for the development of bonded assemblies. Some adhesives (and adherents) are fluorescent, meaning they re-emit light at a different wavelength after being irradiated by some lighting source. This property allows for quantitative analysis of the adhesive failure mode (adhesive and cohesive). A digital image of the fluorescing adhesive or adherent can be analyzed and quantified using publicly available software to determine the relative areas of exposed and covered adherent surface.

Failure mode results are an important (and in some instances, the only) type of data extracted from a mechanical test.

Failure mode analysis can help determine the cause of failure and is often used to screen surface treatment techniques in a research environment.

It is normally difficult, if not impossible, to quantify the relative areas of surface that are occupied by either nothing or by a layer of adhesive. The bare areas and adhesive residues on an adherent are usually very small, irregularly shaped, and poorly contrasted in visible light.

Normally, the relative amounts of adhesive and cohesive failure are determined by direct visual inspection.

Operator approximation and visualization error are common; the operator approximation varies from person to person. Slight changes in color and lighting could have a profound effect on the collected data.

The technique requires a non-fluorescent adherent and a fluorescent adhe-

sive (common for metal specimens that have been bonded with adhesive), a camera with high sensitivity (preferably a CCD sensor), and a light filter to remove reflected light but allow fluorescent light to reach the camera sensor. A UV light source that will cause the adhesive to fluoresce brightly enough to be captured digitally is required. Software is needed to analyze the images.

Use of this fluorescence technique allows a quantitative, repeatable, and objective measurement of the relative amounts of adhesive and cohesive failure in a specimen. The technique is fast, simple, and allows the collection of valuable data in a clear and unambiguous way.

This work was done by Christopher J. Wohl and Thomas W. Jones of Langley Research Center, and Frank L. Palmieri of the National Institute of Aerospace. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Instrumentation category. LAR18215-1

Energy-Based Acoustic Measurement System for Rocket Noise Marshall Space Flight Center, Alabama

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evelopment of the next generation of spaceflight vehicles has prompted a renewed focus on sound source characterization and near-field propagation modeling.

Without advancements in these areas, large uncertainties in vibro-acoustic loading estimates on space vehicles and payloads may result in structural designs that are either insufficient or excessive.

In the near field, even accurate acoustic pressure measurements are insufficient. A set of pressure measurements can reveal the local sound pressure levels at the sensor locations.

However, because of the frequencies and source size inherent to a rocket plume, it would require an extremely large array of distributed microphones to adequately map out the critical near-field region and establish how tile sound energy is traveling outside that region. An improved system for determining this near-field energy flow provides source characterization capabilities beyond traditional pressure measurements.

This project has resulted in the development of a new energy-based measurement and analysis system for rocket noise. The robust hardware and

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novel signal processing algorithms provide NASA with the a unique capability to characterize the near-plume noise environment of full-scale rocket motors. This characterization is necessary to develop physics-based, nearmotor noise propagation models that will aid in improving vibro-acoustic loading estimates on space vehicles and payloads.

The hardware and software development consists of four principal innovations: • An improved energy-based acoustic probe design that extends the operational frequency bandwidth, mini-

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Test & Measurement mizes scattering, and provides easy access to microphone components for calibration, while being robust enough for harsh near-field rocket environments and inexpensive enough to remain accessible. • Improved energy-based signal processing and analysis methods using a newly developed phase and amplitude gradient estimation (PAGE) that provides consistently superior

results in comparison to previous methods. • A rugged and reliable field-deployable data acquisition system that will reduce field test setup time and complexity. • Results from energy-based and other data analyses that detail the nearfield intensity flow, assessment of near-field relationships between energy quantities, and other meas-

ures of interest, including rms and peak levels, acceleration, etc.

This work was done by Kent Gee of Brigham Young University and Michael James of Blue Ridge Research and Consulting LLC for Marshall Space Flight Center. For more information, contact Ronald C. Darty, Licensing Executive in the MSFC Technology Transfer Office, at Ronald.C.Darty@nasa.gov. Refer to MFS33179-1.

Mass Gauging Demonstrator for Any Gravitational Conditions Marshall Space Flight Center, Alabama

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his concept uses an optical interferometric method to determine the density and/or pressure of the gas state contained with tank ullage. The system is similar to compression tank volume methods. By using an optical interferometric technique to determine gas density and/or pressure, a much smaller compression volume or higher-fidelity measurement is possible.

Future space mission concepts are severely limited by the inability to determine the amount of fluid (especially a cryogen) in a tank without some form of stratification (gravity, thermal, etc.). The nature of the fluid in a low- or zero-gravity environment makes metering concepts difficult. The physics governing the flow of liquids under these conditions are dominated by surface tension and viscosity forces.

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Various mass gauging schemes have been tried (or proposed) that require complex modifications or inside surface polishing of tanks. Others rely on complex pumping devices. However, this design is far simpler and effective.

In this innovation, the tank (volume to be measured) is coupled to the measurement system, which is a simple optical cell (chamber connected to the tank with optical windows).

A laser is passed through the optical cell in a Michelson-type interferometer arrangement. This will couple the optical beam to the physical state of the gas in the tank. A small compression is put on the tank, which compresses the gas phase in the tank and changes its density. This density change is “seen� through a shift in the generated optical fringes. Well-established and proven theory is used to quantify the fringe shift into physical units. The novel feature here involves using the optical method to measure the density change in the gas rather than a standard pressure transducer.

The sensitivity of this approach can lead to a 1,000Ă— improvement over the traditional approach, or can lead to a piston 1,000 times smaller for the same performance, which is more of an interest to space applications.

This work was done by William Witherow and Kevin Pedersen of Marshall Space Flight Center, and Valentin Korman of Madison Research Corporation. For more information, contact Ronald C. Darty, Licensing Executive in the MSFC Technology Transfer Office, at Ronald.C.Darty@nasa.gov. Refer to MFS32611-1.

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Test & Measurement

Multiport Hat Coupler for Electronically Steerable Antenna Testing This technology provides the same performance as an anechoic closet, but at two orders of magnitude lower cost.

Lyndon B. Johnson Space Center, Houston, Texas

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his invention provides a lowercost means for verifying the scanning functionality of an electronically steerable (i.e. phased array) antenna (PAA) compared to existing methods that use a scanning probe or scanning test fixture and surrounding anechoic enclosure. This design is comprised of a standard test hat that has been modified to include additional probes located in the positive and negative directions of each scan axis. RF measurements taken from these additional probes provide an esti- An interior view of the prototype multiport test hat. mate of the beam-pointing angle.

This solves the problem of verifying the choic chamber with a scanning probe or platform-installed antenna’s beamscanning test fixture. pointing functionality without the relaBeam-steering measurements are tively high cost of a conventional aneobtainable from this configuration because

the radiated power received by each antenna probe will change with respect to the other probes as the beam is scanned towards or away from it.

A vector network analyzer (VNA) was used to measure the insertion loss of the PAA and test hat, although a scalar measuring instrument such as a spectrum analyzer or RF power meter could be used in conjunction with an RF signal generator. The insertion loss is measured on each antenna probe port for each pointing angle tested. Each antenna probe must be terminated with its characteristic impedance to prevent reflections.

For the prototype characterization, one probe was measured with the 50-ohm load terminations placed on the unconnected

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NASA Tech Briefs, May 2015

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Test & Measurement probes. Production-level testing should make use of a terminated RF switch to minimize the number of mates/demates and streamline the testing.

The multiport test hat must be characterized with a set of reference measurements before it can be used to measure pointing angles. These measurements are made on an antenna that has recently had its pointing performance verified in an antenna test range. Characterization of the three-port prototype test hat revealed

that pointing angle estimation accuracy is best when the antenna scan vector is oriented towards an antenna probe. This was expected, and the production multiport couplers will therefore have five antenna probes (+X, -X, +Y, -Y, and +Z).

This work was done by Joseph Moran, Nicholas Mullins, and Timothy Becker of Lockheed Martin for Johnson Space Center. For further information, contact the JSC Technology Transfer Office at (281) 483-3809.

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Goddard Space Flight Center, Greenbelt, Maryland he Earth’s magnetosphere offers a wealth of information on particle dynamics, acceleration, and trapping. Fast neutrons, produced in the Earth’s atmosphere by the impact of galactic cosmic rays (GCRs) and solar energetic particles (SEPs), are an important but poorly measured component of the radiation environment in the inner magnetosphere. Cosmic ray albedo neutron decay (CRAND), whereby atmospheric neutrons beta-decay into protons and electrons, is a significant source of energetic protons in the inner radiation belt. Current models of the inner proton belt rely heavily on Monte Carlo simulations for the CRAND component, validated primarily by a handful of singlepoint balloon measurements from the 1970s.

A neutral-particle instrument (IRAD FY14) is being built for CubeSat platforms to address several critical science goals of solar and heliospheric physics, as well as the radiation environment in low Earth orbit. A key asset of the instrument is its ability to measure neutral and charged radiation.

The instrument relies on modern scintillators and silicon photomultiplier (SiPM) readout, and is thus inherently robust, costeffective, compact, and modular.

The instrument is a neutron spectrometer with the primary objective of measuring the inner zone equilibrium injection flux by directly detecting the dominant source of high-energy proton albedo neutron decay in the energy range of –10 to 100 MeV. These observations provide a critical input to the CRAND model, enabling a better understanding of dynamics of the inner belts and, consequently, the potential radiation hazards to space-borne assets and local space weather.

Because volume, mass, and power are severely constrained on small satellites, taking full advantage of these platforms will require flexible, compact, lightweight, and low-power detectors to be developed and

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available for rapid integration into payloads. The instrumentation proposed will be based on scintillators with advanced, compact readout and electronics. Scintillator detector materials have a long history in the measurement of gamma rays and neutrons, and provide a variety of advantages for space instrumentation including low cost, high stopping power, straightforward implementation that is readily scalable, room-temperature operation, and good energy and timing resolution.

This work was done by Georgia De Zolfo and David Suhl of Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Instrumentation category. GSC-16991-1

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Goddard Space Flight Center, Greenbelt, Maryland

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iven the increased availability of small satellite opportunities either through CubeSats or the Air Force’s University Nanosat program, and the limited availability of larger platforms, it is challenging to develop new instrumentation that not only fits within the envelope of small satellites, but also addresses the diverse science applications available in low Earth orbit (LEO). While small-platform instrumentation is limited in sensitivity, the ability to populate LEO with a fleet of instruments opens new science objectives not available with larger standalone payloads. Furthermore, coordinated observations of a variety of radiation species that either enter LEO from the Sun or heliosphere directly, or that reside within the radiation belts themselves, are necessary to fully reach closure on complex processes that govern particle acceleration and transport.

An instrument prototype was built and calibrated that can measure energetic gamma rays, neutrons, and energetic particles with good efficiency that can be readily expanded to suit small satellite platforms. A key asset of the instrument design is the ability to measure a broad range of radiation, which can address several critical science goals of solar and heliospheric physics, as well as the radiation environment in LEO. As volume, mass, and power are severely constrained on small satellites, and development funds are limited, taking full advantage of these platforms will require flexible, compact, lightweight, and low-power detectors to be developed and available for rapid integration into payloads. The instrumentation proposed will be based on scintillators with advanced compact readout and electronics.

Scintillator detector materials have a long history in the measurement of gamma rays and neutrons, and provide a variety of advantages for space instrumentation including low cost, high stopping power, straightforward implementation that is readily scalable, room-temperature operation, and good energy and timing resolution.

The instrument concept is based on a compact, low-mass, and lowpower double-scatter neutron/ray/particle detector developed for the Solar Probe Plus mission: the Solar PRobe Ion, Neutron, and Gamma-ray Spectrometer (SPRINGS). SPRINGS is a unique instrument concept that uses a novel configuration of simple, organic scintillator detectors to meet the scientific goals of measuring, in the

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NASA Tech Briefs, May 2015

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Test & Measurement inner heliosphere, solar neutrons (120 MeV) and gamma rays (0.120 MeV).

SPRINGS consists of individual plastic and organic crystal scintillator blocks (3 cm thick) that record neutron and ray scatters, interleaved with thin plastic sheets (5 mm

thick) to detect charged particles.

Incorporating similar blocks made of inorganic scintillator would further improve the gamma ray response, and perhaps extend the energy range for neutron and particle detection.

This work was done by Georgia De Nolfo of Goddard Space Flight Center. For further information, contact the Goddard Technology Transfer Office at (301) 286-5810. GSC-16969-1

Variable Acceleration Force Calibration System Langley Research Center, Hampton, Virginia

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variable acceleration calibration system combines an innovative mechanical system and a statistical design of experiments to calibrate multi-axis force transducers. This system can reduce calibration time, allow for improved calibration of large-scale transducers, provide mobility for on-site calibrations, allow multiple transducers to be calibrated simultaneously, and accommodate dynamic force calibration.

State-of-the-art calibration systems include manual dead-weight calibration stands, automated calibration machines, and the Single Vector System (SVS). All three of these machines rely on generating force under constant gravitational acceleration by changing the mass (force = mass Ă—

acceleration). The current innovation holds the mass constant and changes the acceleration, thereby generating large forces with relatively small masses. This also allows for multiple forces to be applied without changing the mass, and dynamic forces can be applied by oscillating the acceleration.

This design provides improved efficiency and new capabilities for force calibration.

The most recent state-of-the-art calibration system used is the SVS. This system is unique because it is the only force transducer calibration system that uses a single applied force vector — gravity.

By pitching and rolling the transducer, and by changing the location of the applied

gravitational force relative to the transducer moment center, combinations of all six force components can be achieved. This loading technique, in conjunction with a statistically rigorous loading sequence, makes the SVS more efficient and accurate.

In addition, the SVS uses less complex hardware compared to the other calibration systems; hence, it is considered the mechanically simplest of the three systems.

This work was done by Peter Parker, Ray Rhew, and Thomas Johnson of Langley Research Center; and Drew Landman of Old Dominion University. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Sensors category. LAR-18065-1

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NASA Tech Briefs, May 2015

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A Synthetic Quadrature Phase Detector/ Demodulator for Fourier Transform Spectrometers This method makes it possible to use simple, low-cost, high-resolution audio digitizers.

Langley Research Center, Hampton, Virginia

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ourier transform spectroscopy works by measuring a spectral/light signal through a Michelson interferometer. In order to know the wavelength of the signal, one must use a stable reference, which is typically a metrology laser. In a standard Fourier transform spectrometer (FTS) system, the laser signal also runs through the interferometer and the laser beam is guided to a separate detector that is then used to trigger an analog-to-digital converter, which then captures the spectral signal.

One drawback of the standard method is one is restricted to measuring spectral content at half the frequency of the laser light or below due to the Nyquist sampling criteria. Also, velocity control must be very tight because one is sampling in the spatial as opposed to the time domain, which can lead to ghosting of the interferogram. This issue was first addressed by James Brault, who conceived digitizing the signal in the time domain with a high-resolution, 24-bit analog-to-digital converter, triggered by a crystal clock. This allowed him to apply filtering in the time domain, which eliminated the ghosting problem. He used information from an event counter that was triggered by a metrology laser to then resample the data linear in space. This removes the restriction of sampling at half the laser frequency sampling because the velocity variations are slow compared to the sample rate, and the sample rate can be as fast as it needs to be by adjusting the clock frequency independent of the metrology laser. The drawback to this method is it requires special hardware in the form of the high-speed event counter, and velocity correction points are restricted to metrology laser fringe crossings, which are used for the resampling of the data in the space domain. It also requires tuning to align the fringe crossing data with the sampled signal, which can be different from run to run.

In this newly improved method, the analog laser fringe signal is digitized in a separate channel along with the

spectral data, which eliminates the event counter used in the earlier method. Then, the laser signal is demodulated using a heterodyning technique in the form of a software

synthetic quadrature phase detector in combination with phase tracking to derive the slide position for each data point. Two synthetic signals are created, each being 90° out of phase with a

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NASA Tech Briefs, May 2015

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Test & Measurement frequency equal to the average frequency of the laser interference pattern. These two signals are then mixed with the laser signal. Fourier transform filters are then used to isolate the sidebands to derive the phase. Also, since both the laser data and spectral data are synchronous (unlike in the earlier improvement), no tuning is required. This makes for a very simple setup, and high-resolution data can be obtained at any wave-

length, even while using 24-bit audio digitizers found on most modern computers.

The most unique feature of this innovation is to use a synthetic quadrature phase detector and phase tracker to determine an FTS slide position for each digitized point. The main benefit is that one is not restricted to a spectral range dictated by the frequency of the laser, and one does not need any additional hardware

such as an event counter to linearize the data in space. It is also possible to use the same detector for both the metrology laser and the spectral signal since one can isolate each through filtering.

This work was done by Joel F. Campbell of Langley Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Instrumentation category. LAR17694-1

Device for Direct Measurement of the Diffusivity and Molecular Release Through Membranes and Filters Controlled-release systems for drug delivery, molecular sieving, and single-molecule detection use micro and nano structures.

Lyndon B. Johnson Space Center, Houston, Texas

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oncentration-driven molecular diffusion is a fundamental phenomenon essential for the transport of nutrients in cells, for oxygen exchange in the lungs, and mating of chemicals in industrial reactors and the food industry.

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Thus, diffusion plays a key role in a variety of disciplines. The concentrationdriven diffusive transport is commonly described by Fick’s laws of diffusion. It is most often approximated by the StokesEinstein equation, which assumes a

rigid solute sphere diffusing in a continuum of solvent at a low Reynolds number and infinite dilution.

Numerous technologies such as controlled-release systems for drug delivery, molecular sieving, and single-molecule

NASA Tech Briefs, May 2015

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detection are now employing micro and nano structures. In these cases of fluid nano-constraint, the prediction of the diffusivity is no longer accurate.

Experimental investigations have observed a significant difference between the “measured” diffusion coefficient and the predicted values at increasing confinement. In particular, significant deviations occur as the size of channels or pores approaches the size of the single molecules, increasing the importance of molecular boundary interactions.

This work is related to a novel device and method for rapid, inexpensive, and accurate diffusion testing and diffusivity measurement through multiscale channeled or porous media. The invention uses a silicon nanochanneled membrane for drug delivery (nDSl). The device comes in three embodiments, each with its own advantages.

The first embodiment is composed of two stainless steel bodies, two silicon rubber O-rings, two silicon rubber caps, and two stainless steel screws and nuts.

The device bodies are hollow, housing the solvent and solution chamber (approximately 350 µL each). They present a groove that precisely fits the nDSl membrane. A smaller inner groove is also machined to house the sealing O-rings. The membrane is then clamped in between the two bodies, which are pressed together by tightening the screws. The measurement of the amount of molecules diffused during the time is performed by sampling fluids from the sink solution and performing the appropriate concentration measurement for the molecule in analysis.

The second embodiment, developed as a modification of the first, is composed of two stainless steel bodies that house the drug, and the sink reservoirs separated by the nanochannel membrane. The membrane is sealed between the metal bodies through two silicon rubber O-rings. The drug solution reservoir presents a volume of 150 µL, which is capped through a silicon rubber cap. A 4.45-mL sink reservoir is obtained by bonding the lower metal body to a UV macro-cuvette through an UV-curing epoxy resin. This device was designed to allow the measurement of the amount of molecules diffused throughout a membrane or a porous media by means of spectroscopy techniques. In particular, this modification

was invented to avoid the fluid sampling during the test. The avoidance of fluid sampling reduced the experimental error, and simplified the measurement protocol.

The third embodiment represents a modification of the above two embodiments for the rapid, inexpensive, agile, and accurate measurement of the diffusivity through multiscale channeled or porous media. The device is composed of PDMS (polydimethylsiloxane) and

stainless steel bodies, one silicon rubber O-ring, and two stainless steel screws.

The device is simple to operate, can be used with various standard instruments, is inexpensive, and diffusivity measurement is rapid.

This work was done by Arturas Ziemys, Jaskaran Gill, and Alessandro Grattoni of the University of Texas Health Science Center for Johnson Space Center. For further information, contact the JSC Technology Transfer Office at (281) 483-3809. MSC-24821-1

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NASA Tech Briefs, May 2015

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Manufacturing & Prototyping Increased Alignment in Carbon Nanotube Growth Ames Research Center, Moffett Field, California

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he combination of electronic and mechanical properties of carbon nanotubes (CNTs) has led to wide-ranging investigation of their potential in future electronics and computing, sensors, electrodes, and composites. A method and system for fabricating an array of two or more CNT structures on a coated substrate surface was developed.

A single electrode is coated for a selected voltage application and time interval. The CNT structures are grown on a coated substrate surface with the desired orientation. Optionally, the electrode can be disconnected before the CNT structures are grown.

The technology provides separate procedures for generating and aligning growth of an array of single-wall CNTs (SWCNTs), an array of multi-wall CNTs (MWCNTs), and/or an array of carbon

nanofibers (CNFs), with a CNT or CNF length that depends upon the structure involved — generally in the range of 1 to 100 mm.

In one embodiment, an array of SWCNTs is grown by providing a substrate, coated on a first substrate surface with an optional first thickness of a metal underlayer, and coated with a second thickness of one or more active catalysts.

An electrode, having an associated voltage magnitude in a range of 0.1 to 100 V or higher, is connected to the substrate first surface or to a substrate second surface for a time interval of selected length in the range of 1 to 100 s, or higher.

The electrode is then removed or disconnected, or it can be allowed to remain connected. A selected heated hydrocarbon gas intermediate species is passed over the coated substrate to suc-

cessively strip the H atoms and deposit the carbon particles on the catalyst.

Connection of the electrode, even for a time interval as short as a few seconds, will result in CNTs or CNFs that are oriented in substantially the same direction, roughly perpendicular to the coated substrate surface, having CNT lengths in a range of 1 to 1,000 mm.

CNT orientation occurs whether the electrode remains connected to the substrate or is disconnected from the substrate.

This work was done by Lance D. Delzeit of Ames Research Center. NASA invites companies to inquire about partnering opportunities and licensing this patented technology.

Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARCTechTransfer@mail.nasa.gov. Refer to ARC15404-1.

Process to Fabricate Specific Sized Monodisperse Polystyrene Microparticles Langley Research Center, Hampton, Virginia

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new method was developed to prepare monodisperse nano to microparticles of polystyrene ranging from 0.5 to 2.5 microns in relatively large-quantity batches (2 L, 10% by weight in water). Current commercial sources are very expensive and can typically only be acquired on a relatively small scale. Monodisperse polystyrene in this size range is an important component of laser velocimetry measurements in wind tunnels, but has many other potential uses. Polystyrene microparticles have uses in paints/coatings, adhesives, bio/immunoassays, reaction catalysts, and chromatography materials.

NASA Tech Briefs, May 2015

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The main benefits of this technology are low cost, scalability, and selectable size.

Various laser velocimetry techniques require micron-sized particles to be injected in the flow to provide scattering centers for the input laser light. These particles must satisfy two criteria: be small enough to follow the fluid flow with excellent fidelity, yet be large enough to provide adequate scattered light to be detected by the laser velocimeter with sufficient signal strength to yield accurate velocity measurements. Liquid

aerosols and dry powders have been utilized with limited success. Their inherent polydispersity increases the overall signal-to-noise ratios and lack of reproducibility results in questionable velocity measurement accuracy.

A procedure to produce particles with diameters between 0.5 and 2.0 microns was demonstrated using a 3-L reaction kettle with temperature controlled by a heating mantle and a cold finger condenser. The control is operated by a mercury thermoregulator that alternately

calls for heating or cooling, depending on the set temperature versus the sensed temperature. A condenser returns any vaporized reactants to the reaction vessel. A stirring paddle ensures sufficient agitation of the reactants.

This work was done by Pacita I. Tiemsin, Donald Oglesby, and Jackie Schryer of Langley Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Manufacturing & Prototyping category. LAR-17777-1

Atmospheric Pressure Plasma-Based Fabrication of Printable Electronics and Functional Coatings Applications include biomedical, consumer electronics, security, and communications industries.

Ames Research Center, Moffett Field, California

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he need for low-cost and environmentally friendly processes for fabricating printable electronics and biosensor chips is growing. Nanomaterials have proved to be very useful in both printable electronics due to their electronic properties, and in

biosensors for signal transduction, and amplification. Chemical vapor deposition requires high temperatures for the growth of nanostructures, restricting the type and nature of materials that can be used as substrates. Conventional plasma-enhanced

chemical vapor deposition requires high vacuum equipment, and the need for vacuum results in additional costs of vacuum pumps and energy resources.

This work is a unique approach for an atmospheric pressure plasma-based

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NASA Tech Briefs, May 2015

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Free Info at http://info.hotims.com/55589-781

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Manufacturing & Prototyping

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process to fabricate printable electronics and functional coatings.

The fabrication process involves aerosol-assisted, room-temperature printing in which an aerosol carrying the desired material for deposition is introduced into a cold plasma jet operated at atmospheric pressure. The deposition is the result of the interaction of the aerosol containing the precursor material with the atmospheric pressure plasma containing a primary gas.

The plasma process is capable of printing and patterning conductive traces made of metal micro- and nano-structures, carbon nanotubes, conductive polymers, insulating and dielectric coatings, organic functionalities, and inorganic coatings. The deposition process can be modified for depositing multiple materials, either simultaneously or sequentially, and for high-throughput processing by having multiple jets. The technique is independent of the nature of the chosen substrate, and works for substrates such as paper, plastic, semiconductors, metals, composites, and ceramics. The technique can be used for deposition on large areas and the technology is amenable to a variety of platforms.

This work was done by Meyya Meyyappan and Jessica Koehne of Ames Research Center, Ramprasad Gandhiraman of USRA, and Vivek Jayan of Volunteer Internship Program. NASA invites companies to inquire about partnering opportunities and licensing this patent-pending technology.

Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARC-TechTransfer@mail.nasa.gov. Refer to ARC-17266-1.

MANUFACTURING & PROTOTYPING CHANNEL

Sponsored by

Featured Sponsor Video: Designing Text on Plastic Parts In this installment of Design Tips for Plastic Injection Molding, Kevin Crystal explains how to design text on plastic parts. Using the Protomold Design Cube, Kevin gives some helpful tips on font size and orientation for designing text for injection molding. www.techbriefs.com/tv/text-plastic

Human Tissue-Building Device A new device called “BioP3” could someday build replacement human organs the way electronics are assembled today — with precise picking and placing of parts. In this case, the parts are not resistors and capacitors, but 3D microtissues containing thousands to millions of living cells.

Passive Destructive Interference Acoustic Liner for a Turbofan Engine Using Additive Manufacturing

www.techbriefs.com/tv/BioP3-device

3D-Printed Superhero Prosthetic Hands Rice University bioengineers teamed up with Marvel Universe LIVE!, Houston’s Shriners Hospitals for Children, and the global online community e-NABLE to offer a free mechanical hand to the families of eight Shriners patients who lack all or part of one hand.

John H. Glenn Research Center, Cleveland, Ohio

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his technology exploits the capabilities of additive manufacturing to attenuate the fan noise within the inlet or aft duct of a turbofan engine. The approach may be expanded to include auxiliary power units, environmental control systems, or other cooling systems requiring noise attenuation.

The acoustic liner consists of multiple paths to provide passive destructive interference. The passages apply an out-ofphase sound field to incoming sound waves, destructively canceling the energy, creating a reduction in overall sound level in the duct. Additive manufacturing techniques may be used to manufacture the complex pattern of passages that is not feasible using current manufacturing techniques.

The liner is conceptually constructed from cubicle building blocks of a straight-through passage and a right-angle passage.

These blocks can be stacked and nested to produce passages of various lengths from two block widths to an indefinite number.

These configurations can then be arranged axially and circumferentially to produce a complete liner design. The liner can be made from any metallic or non-metallic material suitable for additive manufacturing.

This work was done by Don Weir of Honeywell and Joseph Grady of NASA for Glenn Research Center as part of a Team Seedling Project funded by the NASA Aeronautics Research Institute. For more information, please contact NASA Glenn Research Center’s technology transfer program at ttp@grc.nasa.gov or visit us on the Web at https://technology.grc.nasa.gov/. Please reference LEW-19229-1

www.techbriefs.com/tv/ superhero-hand

Ultralight Material 10,000 Times Stiffer Than Aerogel MIT researchers created a material with the same weight and density as aerogel — a material so light it’s called “frozen smoke” — but with 10,000 times more stiffness. Developed using additive micromanufacturing processes, the material could have a huge impact on aerospace and automotive industries. www.techbriefs.com/tv/ ultralight-material

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COMSOL NEWS

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2015

THE MULTIPHYSICS SIMULATION MAGAZINE

Modeling and Simulation for EVERYONE P. 4

INNOVATIVE BUILDING DESIGN AT NEWTECNIC P. 25 THE SWEET SIDE OF SIMULATION AT NESTLÉ P. 10

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HOW DO I CREATE THE BEST DESIGN AND SHARE MY SIMULATION EXPERTISE?

CONTENTS COMSOL® VERSION 5

Modeling and Simulation for Everyone

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That is the question that engineers, designers, and researchers often ask themselves. This issue of COMSOL News is dedicated to them, as we discuss the paradigm shift happening in the simulation industry, which began with the release of COMSOL Multiphysics® version 5 and the Application Builder.

USING SIMULATION APPS

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As you will find out if you jump directly to page 4, sharing your simulation expertise in an easy and efficient way is now possible using the Application Builder. Experts can now build simulation apps—specialized user interfaces to access their models. These COMSOL users are motivated by their relentless drive for innovation and are leveraging new modeling tools that are customizable, adaptable, and accurate in their handling of the physics involved. They are also sharing their work in such a way that anyone can benefit from it. That’s when the ability to build a simulation app fuels the shift towards “modeling and simulation for everyone”.

Optimizing 3D Printing Techniques with Simulation Apps

HOW TO BUILD AN APP

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Application Builder and COMSOL Server™: A Review

And how can we create the best design? With the right tools, of course, and by learning from our peers. In this edition of COMSOL News, we cover the work of simulation experts from a wide range of industries. Food processing at Nestlé, building physics and architectural design at Newtecnic, corrosion protection in automotive applications at Daimler, laser-matter interaction at Lawrence Livermore National Laboratory, 3D printing at TNO, and many more.

We appreciate the generosity of COMSOL users who have shared their modeling work and best practices. It has been inspiring to work with them and we hope you will find the stories here useful.

FOOD PROCESSING TECH

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The Sweet Side of Simulation: Behind the Scenes at Nestlé

Enjoy!

Valerio Marra Technical Marketing Manager COMSOL, Inc.

AUTOMOTIVE

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Defending Automotive Components Against Corrosive Destruction

INTERACT WITH THE COMSOL COMMUNITY BLOG comsol.com/blogs FORUM comsol.com/community/forums LINKEDIN linkedin.com/company/comsol-inc.

FACEBOOK facebook.com/multiphysics TWITTER twitter.com/comsol_inc GOOGLE+ plus.google.com/+comsol We welcome your comments on COMSOL News; contact us at info@comsol.com

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EDITOR Alexandra Foley, Technical Marketing Writer, COMSOL, Inc.

COMSOL NEWS 2015

© 2015 COMSOL. COMSOL News is published by COMSOL, Inc. and its associated companies. COMSOL, COMSOL Multiphysics, Capture the Concept, COMSOL Desktop, COMSOL Server, and LiveLink are either registered trademarks or trademarks of COMSOL AB. All other trademarks are the property of their respective owners, and COMSOL AB and its subsidiaries and products are not affiliated with, endorsed by, sponsored by, or supported by those trademark owners. For a list of such trademark owners, see www.comsol.com/trademarks

Simulating Laser-Material Interactions PHOTOVOLTAIC MATERIALS

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Simulations for Solar

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Virtual Material Design in 3D Printing Makes Headway with Multiscale Modeling BUILDING PHYSICS

Optimizing the Performance of Complex Building Façades

ACOUSTIC ENGINEERING

Precision Performance: The Pursuit of Perfect Measurement BIOFUELS

Making Biofuel a CostEffective, Renewable Source of Energy

FEATURED VIRTUAL MATERIAL DESIGN IN 3D PRINTING MAKES HEADWAY WITH MULTISCALE MODELING

Simulation Solves the Mystery Behind an Elevator Accident

DAIMLER AND HZG

DEFENDING AUTOMOTIVE COMPONENTS AGAINST CORROSIVE DESTRUCTION

SUSTAINABLE ENERGY

Better Ways to Heat and Cool Buildings COMSOL BLOG

COMSOL Blog Shares the Latest in Multiphysics Simulation

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Simulation Apps Bring Us Closer to Mars

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OPTIMIZING SHAPED METAL DEPOSITION TECHNIQUES WITH SIMULATION APPS

Researchers at the Manufacturing Technology Centre use simulation apps to explore the 3D metal printing technique shaped metal deposition (SMD).

Simulation of hybrid material car components and joints enables innovative design for corrosion protection in automotive applications.

GUEST EDITORIAL

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COMSOL VERSION 5 AND BEYOND

Modeling and Simulation for EVERYONE

This all means that a small group of people is servicing a much larger group of people working in product development, design, or production.

Simulation models are oftentimes so complicated that the person who implemented the model is the only one who can safely provide the input data needed to get useful output. Hence, we have a bottleneck.

by SVANTE LITTMARCK

THE SOLUTION

Scientists like Newton, Maxwell, and others have given us the mathematical models, the “laws of science”, that make it possible to accurately predict how physical objects and systems will develop in space and time given certain boundary conditions and initial conditions. Applied mathematicians have invented numerical methods that can generate numbers and graphics to accurately describe the solution to those laws.

This makes it possible for us to simulate, modify parameters, and ultimately make a better—if not the best—design.

The physics, the math, the computational tools, and the engineering community are all in place to achieve wonders using simulation. Sending exploration vehicles to the surface of Mars that report back to Earth and creating communication devices like cell phones and GPS are just two examples.

Many breakthrough technological innovations have seen daylight in the last several decades. But many areas that would benefit greatly from simulation remain almost untouched by the powerful computational tools available today. Why is this?

THE OBSTACLES

It is a fact that current computational tools are so complicated to use that there are very few engineers trained to do it—at least compared to the number of potential beneficiaries. The setup of mathematical models needs to be done by a mathematician or a physicist. Model simplifications are necessary in order to save computational time, memory, and solution data management. Negligible phenomena should be ignored. The phenomena that should be ignored depend on the application and what is to be achieved. Understanding which physics phenomena to include, which to leave out, and how to model their effects requires a modeling expert.

Once the model is set up, solving the equations numerically means replacing the continuous differential equations with discretized difference equations and points in space and time. The discretization must be done in such a way that the solution to the difference equation converges to the solution of the differential equation.

Otherwise, it has no physical meaning. Additionally, in order to obtain an accurate solution, the discretization must be fine enough.

There are theories for good default numerical solver settings for many physics areas, but they are not all the same. Sometimes, it takes a numerical analysis expert to define the solver settings.

As a result, the typical user of a simulation package is someone who holds a PhD or an MSc and has several years of experience in modeling and simulation. The user also underwent thorough training to use the specific package. He or she typically works as a scientist in a big organization’s research and development department. It is up to that person to employ his or her expertise to create and validate the model and the simulation results.

In order to make it possible for this small group to service a much larger group, there is an obvious solution: Create a simulation package that makes it possible for the simulation expert to build an intuitive and specific user interface for his or her otherwise general model—a ready-to-use application. The application should include user documentation, checks for “input within bounds”, and predefined reports at the click of a button. A simulation application with these capabilities makes it possible for a user to avoid accidental input errors while keeping the focus on relevant output details. The application can then be shared with a larger group of users.

Making this happen is easy compared to the achievements listed in the beginning of this article. It is happening as you read this. The spread of simulation applications will be immediate. No design engineer will want to be left behind. No company can afford to let their competitor get an advantage through earlier adoption.

Eventually, consumers will be running simulation applications to make better purchase decisions.

Svante Littmarck, co-founder and CEO of the COMSOL Group.

Originally published in the January 2015 edition of Desktop Engineering magazine.

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MTC, UK

Optimizing 3D Printing Techniques with Simulation Apps

by ALEXANDRA FOLEY Taking a new technology concept from research in its infancy to a qualified solution ready for industrial use requires rigorous testing and validation. Additive manufacturing (3D printing), for example, first appeared in the early 1980s with a Technology Readiness Level (a method of measuring a technology’s maturity for industry use that was proposed

by NASA in the 1970s) of TRL 1, and it took decades before it exploded on the industrial markets as a hot new manufacturing technique set to change the world.

SIMULATING SHAPED METAL DEPOSITION

Organizations such as the Manufacturing Technology Centre (MTC) in Coventry, UK help to bridge the gap between concept and industry by providing the resources necessary to bring a design from fundamental research (TRL 1–TRL 3) to commercial use (TRL 7–TRL 9). One current endeavor at the

MTC is research into the additive manufacturing technique known as shaped metal deposition (SMD).

“SMD has multiple advantages over powder-based additive manufacturing technologies,” says Borja Lazaro Toralles, Research Engineer in the MTC’s Manufacturing Simulation theme, who has used COMSOL Multiphysics® software to design a model and simulation app of the SMD process (see Figure 1). “Among the benefits of SMD are higher deposition rates, the possibility of building new features upon preexisting components, or even the use of multiple materials on the same part.”

Unlike other additive manufacturing techniques that use lasers to melt a thin layer of powder, SMD deposits a sheet of molten metal—which in some cases can be as expensive as titanium—that is built up layer-by-layer on a surface in a process that is similar to welding. “One of the challenges of this is that thermal expansion of the molten metal can deform the cladding as it cools, resulting in a final product that is

FIGURE 1. Shaped metal deposition (SMD) simulation app created using the Application Builder available in COMSOL Multiphysics.

The app computes the residual stresses generated during the manufacturing process and predicts the final deflection of the part.

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LEVERAGING SIMULATION APPS different than what was anticipated,” describes Lazaro Toralles. “In order to predict the outcome of a proposed design, we need either to minimize the deformations or alter the design to account for them.” Figure 2 shows an example of a part manufactured using SMD, where deformation occurs after six layers of deposited molten metal have been added. A model of the part, also shown in Figure 2, is used to predict the part’s deflection during manufacturing, allowing the designer to update the design accordingly.

COMMUNICATING COMPLEXITY WITH SIMULATION APPS

The MTC has leveraged the Application Builder in order to more efficiently communicate complex FIGURE 2. During the SMD process, thermal cycling induces residual design ideas across multiple simulation and stresses on the manufactured parts. Top: Simulation of the SMD part. process departments, and to allow app users to Middle: The part after just one deposited layer, with no noticeable easily explore the outcome of proposed designs (see Figure 1). Were it not for the simulation app, deformation. Bottom: After six deposited layers, deformation is visible to the naked eye. the testing and validation of a design would be significantly more time consuming and costly using physical testing alone, due to the materials used in SMD. Simulating SMD involves solving a timedependent coupled thermomechanical analysis that predicts residual thermal stresses and deformation, which arise from SMD thermal cycles.

“We built an app using the Application Builder that allows the user to predict whether the deposition process will produce parts that fall within their established tolerances,” says Lazaro Toralles. “If not, then the app provides a user-friendly and cost-efficient way to simulate multiple variations to the input until the results achieve an acceptable final deformation.”

With this app, users can easily experiment with various geometries, heat sources, deposition The MTC team comprising Adam Holloway (left), Borja Lazaro Toralles paths, and materials without concern for the (center), and Willem Denmark (right) have implemented the COMSOL underlying model complexities. Two predefined model, carried out experimental validation, and finally created the SMD parametric geometries are included in the app, COMSOL application. and a custom geometry can also be imported.

Currently, the app is being used by members of the team at the MTC who do not have the simulation ABOUT THE MANUFACTURING TECHNOLOGY experience to independently explore different parts and CENTRE projects for their customers. “Were it not for the app, our The MTC provides a unique environment for simulation experts would have to test out each project we developing cutting-edge technologies into wanted to explore, something that would have decreased the manufacturing processes by bringing the UK's availability of skilled resources,” says Lazaro Toralles. “Using leading academics, engineers, and industry the Application Builder, we can now provide user-friendly app professionals together to develop and demonstrate interfaces to other MTC teams.” The MTC will also offer an new technologies on an industrial scale. This app program for their customers. allows clients to develop new manufacturing “The use of simulation apps will help us to deploy processes in a safe, neutral industrial setting technologies at higher TRLs for their practical use in an without the constraints of a commercial production industrial environment,” Lazaro Toralles concludes. “The environment. Their members include over 80 Application Builder provides us with a powerful development organizations, including BAE Systems, GKN, HP, GM, platform through which we can package complex multiphysics Airbus, and Rolls Royce. models and make them accessible to the wider public.”

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ZINK IMAGING, MA, USA

APPLICATION BUILDER AND COMSOL SERVER™: A REVIEW

by WILLIAM T. VETTERLING

COMSOL Multiphysics® software version 5.0 introduces something new to the modeling enterprise: The Application Builder, and its counterpart, COMSOL Server™. The Application Builder allows the modeler to sweep away the detail-oriented tools that were used to produce a model and to fashion a more approachable application—an app—that is intuitive and easy to use.

The app may have a simple interface constructed with an assortment of buttons, lists, menus, graphics, and text to make its operation straightforward. It may be launched from within the COMSOL Multiphysics program. But, importantly, it may also be lifted entirely from that feature-rich environment with the help of a worldwide COMSOL Server license. In the latter case, the app may be run as a standalone application, or as a web resource within a browser.

There are many scenarios in which the Application Builder will find potential uses. With an app, modeling results may be presented in the form of live, real-time examples rather than static summaries in charts and graphs. Likewise, apps may be constructed for use in lectures or demonstrations. Companies may offer simulation apps demonstrating their product’s performance, to be used in place of data sheets, or may produce licensable apps as products in their own right.

In brief, the Application Builder is a new line of communication between the professional modeling expertise of the model builder, and the science and engineering expertise of model users.

Voltage may be applied to selected electrodes of the print head to heat corresponding portions of a resistive film, and the purpose of the model is to discover the final temperature distribution in the film.

To implement the model as an app, I used the Application Wizard.

The wizard starts with a COMSOL® software model FIGURE 1. Idealized print head and assembles lists of schematic. elements from the model that are suitable for use as inputs and outputs, modeling operations, and graphics.

I selected the number of electrodes and their width as inputs, a command that constructs the geometry and another that executes the model as operations, and plots of the

HOW TO BUILD AN APP

Creating an app is easy enough to try. I began with a functioning COMSOL Multiphysics model that I wanted to turn into an app. I chose to use a simple 3D model of the current distribution and heating of a multi-pixel thick-film thermal print head such as might be used in a fax machine (see Figure 1).

FIGURE 2. A screenshot of the app I built using the Application Wizard.

COMSOL NEWS

Abridged piece, originally published in February 2015 on the Physics Today website.

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HOW TO BUILD SIMULATION APPS object geometry and the surface temperature as graphics.

With these selections, the result was a working app that has input or display boxes for the input/output data, buttons for the actions, and display panels for the graphics. The app components, or widgets, are displayed on a canvas, and can be dragged with the mouse to suitable locations for an attractive interface. A Test Application button allows me to launch the new app and test its features from within the COMSOL design environment. Figure 2 shows the app I built from my model using the Application Wizard.

FULL POWER AHEAD

The Application Wizard is quick and produces a user-friendly version of a model in just a few minutes, but it does not exercise the full power of the Application Builder. If I want to build something a bit more impressive, an array of tools can help assemble fully featured apps. For that purpose, the Application Builder has two sub-tools: the Form Editor and Method Editor.

The Form Editor is primarily used to generate the page layouts that comprise an app. It offers a wide selection of graphical user interface widgets, and users specify sequences of actions associated with each of them. Examples include buttons, check boxes, combo boxes, radio buttons, text boxes, sliders, and tables. The Form Editor also offers a progress bar, a message log, an equation widget displaying formatted LaTeX equations, and a results table.

The second sub-tool is the Method Editor, which is essentially a Java® programming environment that allows users to combine the COMSOL® interface with Java® programs and libraries in order to add additional functionalities.

The Method Editor also has capabilities related to modeling.

As a Java® programming environment, it can, of course, implement Java® code, classes, and libraries from any source.

However, it can also interact with the COMSOL model tree and the COMSOL API in a number of useful ways. For example, a recording feature allows users to turn on the recorder, carry out operations in the model tree (such as creating a graph, or specifying a mesh), and then turn off the recorder to find the equivalent Java® code added to the method.

FURTHER EMBELLISHMENTS

After attending a COMSOL workshop on the Application Builder and reading Introduction to Application Builder, I spent a day embellishing the original app. The new app, shown in Figure 3, has a toolbar at the top and has the tasks of geometry definition, model execution, and display of results divided into separate pages. The first of the tabbed windows allows specification of the print head pixel count and dimensions, and then draws the print head (the geometry is also constructed and resized to fit in the graphics window).

The second tab of the app, which is shown in Figure 3, has two functions. The selection box produces a drawing of the geometry in the graphics window. This is a live drawing, and clicking any of the electrode boundaries results in the application or removal of a voltage on that boundary.

Clicking the Compute button carries out the meshing and solving operations during which a progress bar appears on

the lower right to track the progress.

On completion, the model sounds a chime and prepares several report pages with further results: One is a 1D cut through the 2D surface temperature data to show the temperature profile through the centers of the pixels, while two others normalize the temperature data and apply the typical response curve of an indium antimonide detector.

This is the distillation of my few hours with the Application Builder. Creating an easy-to-use interface is not an onerous task, and there is satisfaction, even for a skilled model builder, in seeing the clutter removed before setting about using a model productively.

The major contribution of the new tools added in COMSOL Multiphysics 5.0 is the ability to integrate the development into a single tool, to greatly simplify the interaction with the API, and to provide a standalone server that is separate from the detail-oriented model development tools. This change promises to make the user interface a more natural and commonplace part of the model development process, and to engage a much wider audience in the use and appreciation of multiphysics models.

William T. Vetterling is a research fellow and manager of the Image Science Laboratory at Zink Imaging, as well as a co-author of the Numerical Recipes series of books and software.

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FIGURE 3. Apps built using the Application Wizard can be embellished later with forms and other enhancements.

Oracle and Java are registered trademarks of Oracle and/or its affiliates.

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Monika Weber, Founder and CEO of Integrated Microfluidic Devices, was the Grand Prize Winner of the 2011 Create the Future Design Contest.

Mark Wagner, President of Sensorcon, Inc. Grand Prize Winner of the 2012 Create the Future Design Contest.

The team at SunFriend Corporation (l-r) Leonard Egan, Siddharth Potbhare, Karin Edgett, and Shahid Aslam (not pictured — Tariq Aslam).

Winners of the 2011 Consumer Product Category.

The Future Starts With

You

Salim Nasser (left), CTO and Co-Founder of Rowheels, Inc., was the Grand Prize Winner of the 2010 Create the Future Design Contest.

Bill Zebuhr, Co-CEO and CTO of Aquaback Technologies.

Sustainable Technologies Category Winner of the 2012 Create the Future Design Contest.

THE

Your future starts here: www.createthefuturecontest.com S P O N S O R E D

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The Sweet Side of Simulation Behind the Scenes at Nestlé

Researchers at the Product Technology Centre in York, UK use simulation to perfect chocolate production at Nestlé.

by ALEXANDRA FOLEY

Aero 10a and KIT KAT COMSOL are registeredNEWS trademarks of Societe des Produits Nestle S.A. Corporation Switzerland

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QUALITY ASSURANCE | FOOD PROCESSING TECHNOLOGIES At Nestlé, the research, design, and manufacturing that goes into producing one perfect bar of chocolate candy is a mesmerizing process, not entirely different from the spectacular world of Willy Wonka’s chocolate factory.

While there may not be umpa-lumpas overseeing candy production, a lot of thought and quite a bit of simulation goes into perfecting the process.

Engineers at Nestlé’s Product Technology Centre in York, UK (PTC York) work, among other things, on the research and development of three different products: a chocolate depositor for making candy bars; a wafer baking plate; and an extruder, used to cook and sort cereals at the same time. At PTC York, which is home to the research and development of Nestlé’s confectionery products, engineers rely on multiphysics simulation to optimize and streamline the production process.

CHOCOLATE R&D

Candy bars, such as Kit Kat®, Aero®, Crunch, and solid milk chocolate bars are produced using a chocolate depositor that fills a mold with molten chocolate. Chocolate enters the depositor via an arm at the top and exits into a mold through each of the nozzle tips (see Figure 1).

“Ensuring that the amount of chocolate in every bar is consistent means that the flow rate and pressure of the chocolate exiting each nozzle must be the same,” says William Pickles, a process engineer at Nestlé. “Not only do we need to make sure that each chocolate bar is the same weight for cost effectiveness and standardization, but we are also committed to guaranteeing that the calorie information on the package is correct as well. This allows us to deliver products with exact nutritional content that fit in with our customers' balanced diets.”

In order to achieve this standardization, the uniformity in flow and pressure between each nozzle tip must be precise to within a narrow margin.

To achieve this consistency, Nestlé uses a combination of modeling and simulation tools. The chocolate depositor shown in Figure 1 was first designed using SOLIDWORKS® software and the geometry was then imported

FIGURE 1. Top: SOLIDWORKS® software geometry of the depositor. Bottom: COMSOL Multiphysics® simulation showing the magnitude of chocolate flow in the depositor’s nozzles and flow channels.

FIGURE 2. Probes located at each of the nozzle tips and in the flow channels demonstrate that the chocolate flow rate and pressure within the depositor and nozzles vary within specifications. Streamlines show the direction of chocolate flow.

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QUALITY ASSURANCE | FOOD PROCESSING TECHNOLOGIES into the COMSOL Multiphysics® simulation software for analysis.

Simulation was used to perform fluid flow optimization, test mechanical stress, and analyze the thermal properties for a particular geometry.

“Every chocolate manufacturer has their own special recipe that produces chocolate with unique characteristics,” says Pickles. “We were able to fully model the non-Newtonian behavior of Nestlé’s signature chocolate by setting up a simulation where an experimental curve relating the shear rate to the shear stress of the fluid was imported into the software. This way, we were sure that we were modeling chocolate with the same fluid properties as the real product.”

Using simulation, the team identified areas of high and low flow rates and

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FIGURE 3. Two wafer-baking plates (a) are used to bake Kit Kat® wafers. The top and bottom plates compress the batter (b), while the flame underneath the plates bakes the wafer (c).

“Every chocolate

manufacturer has their own special recipe that produces chocolate with unique characteristics. We were able to fully model Nestlé ’s signature chocolate using COMSOL Multiphysics.”

–WILLIAM PICKLES, PROCESS ENGINEER AT NESTLÉ

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determined the differences in flow between each of the depositor needles.

Numerical probes in the flow channels and at the tips of the nozzles were used to analyze conditions at certain locations of the geometry.

“By optimizing the depositor design, we were able to achieve a flow rate through each of the nozzles that is consistent to within a tenth of a percent of the desired value,” says Pickles. These results of this simulation are shown in Figure 2.

SIMULATION SAVES THE CRUNCH

What would a Kit Kat® be without the well-known snap of the wafer baked inside? When baking a wafer, uneven heating can cause different moisture concentrations within the wafer, ruining its crunchy texture or even causing it to spontaneously snap.

The wafer baking process at Nestlé uses two baking plates that compress the batter between them (see Figure 3). During baking, the plates are passed above a series of about 40 flames.

“We are using simulation to optimize the baking plate design by looking at the flow of hot air below and around the plates to ensure that we have an

FIGURE 4. Airflow around the baking plates.

FIGURE 5. Left: Temperature distribution in the baking plates’ supporting frame.

Right: Temperature profile at the surface of the top baking plate, where warmer spots can be seen at the location of the bolts (white circles).

Aero and KIT KAT are registered trademarks of Societe des Produits Nestle S.A. Corporation Switzerland

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QUALITY ASSURANCE | FOOD PROCESSING TECHNOLOGIES even temperature profile across the plates' surfaces,” describes Pickles.

“Our aim for this study is to correct burner power and orientations to give the best wafer, while simultaneously reducing the amount of fuel we use.” This fits with Nestlé’s policy of continually seeking to improve efficiency in all of its manufacturing processes.

The flames underneath the baking plates were modeled as jets of hot air, where heating proceeds via convection.

Figure 4 shows the profile of the flame underneath the baking plate and the airflow around the plate.

“We were able to validate our model against baking plates used in experiments, and we found that our simulation results were in very good agreement,” says Pickles. The results also show how warmer spots occur due to increased heat conduction through the bolts holding the baking plates together (see Figure 5).

“The next step will be to optimize this design to distribute the heat as evenly as possible across the top of the plate and minimize temperature peaks,” says Pickles.

COOKING WHILE EXTRUDING

Cereals such as Cheerios®, Trix®, Nesquik®, and many others are made at Nestlé using an extruder. “The hightemperature extruder used at Nestlé

to make certain types of cereals works by forcing dough through a die. The pressure and friction created during this process causes the dough to cook through viscous heating,” says Pickles, referring to the extruder shown in Figure 6. “Extruders are common because they are a compact, cost-effective way of manufacturing products.”

Pickles is working on designing the housing for a viscometer that can be placed within the extruder to measure the viscosity of the dough entering the die. This will ensure consistent quality of the dough so that it will cook in a predictable manner. “For our design, we needed to make sure that the viscometer housing could withstand the high pressure within the device,” says Pickles.

In the original extruder design, the pressure was too high for the viscometer housing to withstand.

“We redesigned the housing, which helped to reduce the pressure. We were then able to make sure that the die design didn’t exceed the yield stress so that the viscometer could safely be housed inside it,” says Pickles. Additionally, simulation was used to check that the displacement of the extruder was consistent, as varying displacement of the device would cause the cereal being produced to have uneven shapes and sizes (see Figure 7).

FIGURE 6. Extruder geometry.

BETTER, SAFER PRODUCTS WITH MULTIPHYSICS SIMULATION At Nestlé, simulation is a big part of the design process, from producing chocolate to wafers to cereals and everything in between. “Since Nestlé products are going to be consumed by our customers, we need to be able to ensure that our designs will hold up in the real world,” concludes Pickles.

“We are confident in the results obtained from our simulations, and we know that they can be trusted to help us produce the best and safest designs possible. This in turn allows us to consistently deliver tastier and healthier products.”

FIGURE 7. Viscometer housing and die simulation results. Left: Contour of von Mises stress. Right: Slice plot of the total displacement.

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Cheerios, Nesquik, and Trix registered trademarks of General Mills IP Holdings II, LLC

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DAIMLER, GERMANY AND HZG, GERMANY

Defending Automotive Components Against Corrosive Destruction

FIGURE 1. Left: Clean rivet. Top right: Rivet showing magnesium hydroxide deposit (white growth) due to corrosion. Bottom right: Magnification of a rivet in a test sheet.

Simulation of hybrid material car components and joints enables innovative design for corrosion protection in automotive applications.

by LEXI CARVER Glance at a bridge’s support beams while stuck in traffic, examine the door of an airplane while waiting to board, or check around the hood of your car, and you will see the small, round heads of rivets holding different surfaces together. Found in metal-bodied vehicles and support structures across the transportation industry, these rivets usually go unnoticed despite their role in joining components that withstand enormous mechanical stress. Some cars contain over 2,000 of them.

As automotive design trends move toward lightweighting and the use of multiple metals, so do the questions surrounding a destructive, invisible

culprit whose handiwork is often only noticed once it is too late: corrosion.

THE CLASH OF METALON-METAL: GALVANIC CORROSION

Galvanic corrosion is an omnipresent process that costs the automotive industry billions of dollars each year.

Caused by chemical reactions between different metals coming into contact with one another, this type of corrosion in some cases is visible as a white powdery growth that forms on the surface of metal parts (see Figure 1, top right). Bubbling paint and deteriorating aluminum are telltale signs

that metallic ions are being exchanged and degrading the surface of the metal.

Different metal combinations react differently to environmental influences, and a number of factors such as joining techniques, material properties, and surface roughness affect the chemical reactions occurring on rivets and the sheets they bind together.

Hence, understanding the underlying electrochemistry is essential to developing robust corrosion protection.

Eager for faster testing and better protection methods, engineers at Helmholtz-Zentrum Geesthacht (HZG) and Daimler AG joined forces to investigate corrosion prevention using multiphysics simulation. HZG is a German institute focusing on materials, medical technology, and coastal research; Daimler AG is the manufacturer of the highly-revered Mercedes-Benz automobiles. The two

FIGURE 2. Left: Geometry depicting half of a punch rivet joint in COMSOL Multiphysics® software. Right: Simulation results show the current density at the surface of the rivet and sheet metal. The simulation mathematically models current flow at the rivet-sheet interface; the highest current density occurs at the sharp edge.

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CORROSION PROTECTION | AUTOMOTIVE

FIGURE 3. COMSOL® software plot showing the localized current density at different positions on the surface of the rivet joint. teams sought ways to streamline rivet design and development, minimize physical testing, and reduce the need for subsequent steps such as surface treatment.

MULTIPHYSICS MODELING OFFERS INSIGHT INTO CORROSION KINETICS

To study galvanic corrosion kinetics, including material loss, surface conditions, and the long-term behavior of the interacting metals, Dr. Daniel Höche, scientist at HZG, created a simulation of a steel punch rivet joint using the COMSOL Multiphysics® software. The rivet is plated with an aluminum-zinc alloy that acts to cathodically protect the steel.

The software allowed Höche to analyze the electrochemical interactions at the surface and edges of the rivet, predict the decay of the adjoined sheets, and adjust the geometry to minimize corrosion.

His model consists of the rivet, bonded metal sheets of aluminum and magnesium, a 0.1% NaCl electrolyte layer on the surface representing the outside environment, and a galvanic couple at the interface between the rivet and the sheets (see Figure 2). He also added a corner bur in the rivet

geometry to simulate the presence of a sharp edge, which increases gradients in the electrolyte potential. This in turn increases current flow and hastens the electrochemical reactions that cause galvanic corrosion.

As the interface between the rivet

and the sheets experiences corrosion, the magnesium sheet begins to degrade more rapidly than the other metals. The chemical reaction produces magnesium hydroxide (Mg(OH)2) that forms a weak barrier film on the surface. Growth in this deposit layer actually increases resistance to further corrosion, hindering its own progress. A complete stop cannot be reached because of the porosity of the Mg(OH)2, however, and the growth continues deeper into the metals.

In order to determine the electric current distribution and analyze the chemical response, Höche needed to account for this non-constant growth and the influencing material properties.

Using the Chemical Reaction Engineering Module and Batteries & Fuel Cells Module, two add-ons to the COMSOL® software, he treated the rivet and the sheet metal like a set of electrodes. This allowed him to assess how the anode/ cathode area ratio, the electrolyte exposure duration, and the changes in electric current due to Mg(OH)2 buildup contributed to magnesium degradation.

“Since the porosity directly affects the barrier properties, the resulting surface topology is influenced by the downward degradation velocity and the opposing growth of the deposit. Basic galvanic current density computations

FIGURE 4. A corrosion test on a galvanized steel sheet showing visible corrosion in the scratched layers (view from above). Bösch created several initial scratches of varying depths and widths in order to analyze the influence of the scratch size on the delamination process. Results are shown after one week (top) and five weeks (bottom).

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FIGURE 5. Left: Close-up of a cross-section of the test sheet where a scratch has destroyed part of the e-coat and zinc layers.

Right: The COMSOL Multiphysics® software results showing the electric potential in the e-coat and electrolyte. The white region indicates the remaining zinc after much of it has already been consumed. were modified by these layer growth aspects,” Höche commented. “This led us to study time-dependent variations in the electrochemical response of the electrodes.”

The model includes chemical reaction rates, known electrochemical properties of the metals, and a time-dependent function with an exposure period of 24 hours. His results report the electric potential and the current density when the rivet joint is exposed to the electrolyte, and reveal the surface coverage (the proportion of the sheets and rivet surfaces covered by Mg(OH)2) at different times after immersion begins. The current density varies over distance from the center of the rivet, showing where corrosion will occur most rapidly (see Figure 3).

and allow moisture and environmental electrolytes access to electrically conductive surfaces. In car paneling, small impairments can create a galvanic couple that causes delamination—the debonding of coatings on the metal sheets—which significantly weakens the corrosion protection.

To analyze this additional risk, Höche worked with Nils Bösch, researcher at Daimler AG, to study delamination on a zinc-plated steel test sheet electrocoated with a layer of cathodic paint called an e-coat (see Figure 4).

“Due to a scratch extending down to the steel surface, you can get a galvanic couple between the zinc and the steel and the zinc corrodes,” explained Bösch. “This results in a crevice that grows continuously between the e-coat and the steel in the horizontal direction, rather than vertically DIGGING DEEPER: THE through the layers.” This behavior is RISKS OF DELAMINATION quite similar to the process of crevice In addition to galvanic corrosion occurring corrosion, which digs between two at the rivet-sheet interface, other surfaces, creating fissures in the metal. automotive components are in danger of Stress fractures at the base of these being destroyed by the elements. Minor, cracks can eventually cause part failure, seemingly superficial imperfections, even though the obvious damage and such as a scratch in the coating or paint overall material loss may appear small. on a panel, open the door to corrosion Höche and Bösch used parametric sweeps in COMSOL to study the electric potential in the electrolyte and the e-coat for different e-coat barrier properties.

Their model reported the corresponding horizontal growth of the crevice as it consumes the zinc (see Figure 5).

Their study to understand how the size of these surface defects impacts the rate of zinc consumption is ongoing. So far, the model indicates that the width of these defects has a greater influence Left: Dr. Daniel Höche, scientist at HZG. Right: Nils Bösch, researcher at Daimler AG. than the depth: a smaller cathode/anode

LAYING THE GROUNDWORK FOR LONGER-LASTING STRUCTURAL SUPPORT

Although corrosion is an omnipresent process that cannot be avoided entirely, it can be minimized through expert design and careful analysis. Höche and Bösch reduced the sharp edges in the rivet joint and honed the geometry to minimize the exposed area while maintaining mechanical stability. They also recommended an e-coat for the sheet metal that, based on the parametric study, would exhibit the lowest electric current and therefore the least decay in the paneling. Their COMSOL models offered indispensable insight into the relevant electrochemical behavior, providing the engineers at HZG and Daimler AG the tools for optimizing their rivet joints for the best corrosion defense.

“This kind of computer-aided analysis enhances the developments in lightweight design and enables identification of possible corrosion problems early in the design cycle,” Höche concluded. “Despite the dangerous enemy that corrosion is to the automotive rivet, control of magnesium corrosion through knowledge-based processing and careful geometric design has come within our reach.”

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ratio and more limited diffusion is present in the narrower scratches, which slows the corrosion process compared to a wider impairment. The existing results are being used to further investigate coating flaws for their negative influence on corrosion protection.

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LAWRENCE LIVERMORE NATIONAL LABORATORY, CA, USA

SIMULATING LASER-MATERIAL INTERACTIONS Lawrence Livermore National Laboratory researchers use multiphysics simulation to develop techniques to repair fused silica optics.

by CHRIS HARDEE

Tunable and precise, lasers are used extensively in everything from common household devices to state-of-the-art research facilities. Prominent everyday uses include automotive parts, barcode scanners, DVD players, and fiber-optic communications. Lasers are, perhaps, less well known as precision heat sources. However, it is this particular characteristic that makes them a very effective tool for material processing applications, where they are used to manipulate or alter specific substances such as glass, metals, or polymers with nanometer-scale accuracy.

Understanding the interaction of lasers with materials is the key to designing and optimizing laser systems for any application. It is these complex laser-material interactions that Manyalibo Matthews, deputy group leader in the Materials Science Division of the Lawrence Livermore National Laboratory (LLNL), studies. His research pertains to the repair and maintenance of fused silica optics in the most expansive laser system in the world.

USING LASERS TO REPAIR HIGH-POWER SYSTEM OPTICS California-based LLNL oversees the National Ignition Facility (NIF), home to the world’s largest and most energetic laser. The giant machine—with 192 separate beams and 40,000 optics that focus, reflect, and guide those beams— can amplify emitted laser-pulse energy by

as much as ten billion times and direct it towards a target about the size of a pencil eraser. The laser produces temperatures, pressures, and densities that are similar to those found in the cores of stars, supernovae, and large planets.

Astrophysics and nuclear researchers use the giant laser to better understand the universe, utilizing such technologies as inertial confinement fusion (ICF), where hydrogen fuel is heated and compressed to the point where nuclear fusion reactions take place.

However, repeated use of this powerful laser can damage the optics within the system. “The optics can be quite expensive,” says Matthews. “The high-power laser light generated by the NIF can damage some of the fused silica optics, creating little pits in the surface—similar to the ding you get when a rock hits your car’s windshield. We do everything we can to repair and recycle the damaged ones.” An example of two damaged optic surfaces before and after repair is shown in Figure 1.

Although the energy deposited by repeated laser use is damaging to the optics over time, lasers can also aid in their repair. In contrast to the giant laser system in the NIF, which spans three football fields, the lasers used to repair damaged optics are smaller, tabletop systems that are integrated with beamand pulse-shaping components to produce a damage mitigation system.

Matthews’ recent research at LLNL focuses on novel techniques for optic

FIGURE 1. Examples of optics damaged by repeated exposure to high-peak-power laser pulses. Damaged optic surfaces are shown in (a) and (c) and the corresponding repaired site is shown in (b) and (d). A slow annealing process was used to repair the damaged site in (a), while the rapid microshaping technique currently employed at NIF was used to repair the site in (c) so that it is optically benign. repair and more broadly encompasses laser interactions with fused silica or glass1.

SIMULATING LASERGLASS INTERACTIONS

Matthews and his team have used simulation to explore three techniques for repairing damaged optics: infrared (IR) pulsed laser microshaping/ micromachining, slow annealing, and laser chemical vapor deposition (L-CVD)2.

In a first research cycle, they focused on the basic underlying physics and COMSOL NEWS

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REPAIRING HIGH-POWER SYSTEM OPTICS | LASER-MATTER INTERACTION material science of how fused silica behaves when exposed to laser light at varying temperatures.

There were several milestones in their temperature-tiered campaign: The first was to understand the thermalelastic response of the material up to the glass transition temperature of 1,300 K, where fused silica exhibits a sudden increase in elastic response and becomes less resistant to flow. They continued by examining the molecular relaxation of glass under viscous flow between the glass transition and the

FIGURE 2. Simulation results showing Marangoni flow of laser-heated glass.

This effect occurs when laser heating leads to gradients in temperaturedependent surface tension, which causes material to flow radially outward, forming what looks like ripples or layers.

evaporation point at ~2,200 K. The final objective was to investigate the evaporation and redeposition of the material over temperatures between 2,200 and 3,400 K. To explore specific techniques for repairing the damaged optics, Matthews turned to the COMSOL Multiphysics® software. “I decided to use COMSOL to get a better understanding of what was going on,” says Matthews. “All the necessary physics were already available in the software, so I could readily try out ideas and avoid the time and effort that would be needed to develop my own code from scratch.”

According to Matthews, COMSOL has been instrumental in helping them understand how lasers interact with fused silica, as well as in refining their specific repair methods. “A high-power laser system can’t tolerate much surface roughness in the optics. Controlling flatness to such high standards required extensive simulation,” he says. His simulations include heat transfer in fluids, chemical reactions, and structural mechanics, as well as mass transport and fluid flow.

IR-PULSED LASER MICROSHAPING

While the simple approach of slow annealing was first used to mitigate

optic damage (see top panels of Figure 1), experimentation and simulation showed that surface rippling caused by thermocapillary flow, or Marangoni shear stress, leads to unwanted light modulation when such surfaces are placed into a laser beam.

A simulation showing the laser-induced temperature profile and material displacement due to Marangoni shear stress is shown in Figure 2.

To counter this effect, Matthews and colleagues explored the use of shorter (10’s of microseconds compared with minutes) laser pulses to precisely “machine” away material into a shape that is less prone to downstream light modulation when placed in the laser system. In Rapid Ablation Mitigation (RAM), an IR laser is used to heat the substrate just beyond the evaporation point, which precisely removes a small amount of material, leaving behind a smooth, fractureless surface. This nano-ablation of material is repeated thousands to millions of times to produce a smooth, conical-shaped pit, which is “optically benign” in that it does not produce downstream light modulation (see bottom panel of Figure 1).

“Despite the long history of IR-laser processing of silica optics,” Matthews says, “few attempts have been made to understand the energy coupling and heat flow in order to optimize the process. We were able to answer many of these questions by simulating a wide range of laser parameters and material properties in COMSOL.” Results from the simulations for temperature and material behavior in the ablated regions compared well with the team’s experiments. “What we learned in our research is far-reaching,” Matthews says, “and can be applied beyond the repair of damage in our high-energy, pulsed-laser systems to virtually any system that requires laser polishing, annealing, and microshaping of silica surfaces1.”

LASER CHEMICAL VAPOR DEPOSITION FOR LARGE REPAIRS FIGURE 3. Schematic showing the optically coupled gas nozzle used for laser-based CVD processing, which allows gas flow to enter through a lateral port while IR laser light enters axially through a ZnSe window.

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The third approach the LLNL team studied for repairing damaged optics was laser-based chemical vapor deposition (L-CVD). In this additive

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REPAIRING HIGH-POWER SYSTEM OPTICS | LASER-MATTER INTERACTION process, a silica precursor gas is “flowed” onto the surface through a nozzle. A focused CO2 laser beam, coupled into the nozzle through a window (see Figure 3), decomposes the precursor and deposits solid SiO2 glass into the damage pit. L-CVD is being explored to repair large defects on optic surfaces with nanoscale precision that are difficult to fix using IR microsphaping or other subtractive approaches. Ultimately, the optic performance can be entirely restored.

“Using simulation, we experimented with how beam intensity, position, and pulse duration affected the amount of material deposited onto the optic,” explains Matthews. Simulation can determine the concentration and flow of the silica as it decomposes, as well as the location of deposited material (see Figure 4).

The team found that the laser power was a critical process parameter for avoiding the unwanted features that are common in many L-CVD deposition profiles, such as the well-known “volcano” feature.

“To date, we know of no other approach that additively repairs damage by replacing lost material with high-grade substrate material,” says Matthews. “Successful application of such a method could reduce processing costs, extend optic lifetime, and lead to more damage-resistant optics for highpower laser applications in general. In addition, L-CVD can offer advantages over conventional methods for other material systems beyond silica glass. The ability to simulate the transient flow, reaction, and heat transport are critical to exploring new applications.”

FIGURE 4. Simulation of velocity and temperature fields for L-CVD. Left: Velocity contours associated with the L-CVD precursor flow from a 3 mm diameter nozzle and the temperature field induced by laser heating at the air-glass interface.

Right: Velocity streamlines of the vaporized silica where diffusion-dominated transport of the glass in the lower left corner can be seen (dark blue). research, however, does not stop at optics repair. Mathews and his team are also supporting a laboratory-wide Additive Manufacturing Initiative by further developing an additive process for 3D printing known as selective laser melting (SLM)3. “I’m really excited about this research,” says Matthews.

“Figuring out how to optimize the 3D printing system could have a huge impact on this rapidly growing industry, which could benefit tremendously from a model-based approach, which was largely trial-and-error in the past.”

REFERENCES M. J. Matthews, S. T. Yang, N. Shen, S. Elhadj, R. N. Raman, G. Guss, et al., “Micro-Shaping, Polishing, and Damage Repair of Fused Silica Surfaces Using Focused Infrared Laser Beams,” Advanced Engineering Materials, vol. 17, p. 247, 2015.

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M. J. Matthews, S. Elhadj, G. M. Guss, A. Sridharan, N. D. Nielsen, J.-H. Yoo, et al., “Localized planarization of optical damage using laser-based chemical vapor deposition,” in SPIE Laser Damage, 2013, pp. 888526-888526-9.

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N. E. Hodge, R. M. Ferencz, and J. M. Solberg, “Implementation of a thermomechanical model for the simulation of selective laser melting,” Computational Mechanics, vol. 54, pp. 33-51

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FROM GLASS REPAIR TO MANUFACTURE

While the L-CVD process is still exploratory for optics refurbishment, the team has implemented CO2 laserbased surface microshaping at NIF, optimized using multiphysics simulation, as part of the facility’s optics mitigation program. Through 2014, over 130,000 damage sites have been repaired using IR microshaping and other techniques, and the optics are continuously being recycled back into the NIF, enabling its routine use.

Their laser-material interaction

Optical damage mitigation and laser materials processing research team at LLNL (from left to right): Gabe Guss, Nan Shen, Norman Nielsen, Manyalibo Matthews, Rajesh Raman, and Selim Elhadj. The apparatus in the background is used to study the dynamics of metal powder melting under high-power laser irradiation, a topic important to the field of metal-based additive manufacturing (3D printing).

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EMIX, FRANCE

Simulations for Solar EMIX uses multiphysics simulation to optimize its cold crucible continuous casting process for the manufacture of photovoltaic-quality silicon.

by CHRIS HARDEE The massive semiconductor industry is built on a firm foundation of micro-thin wafers of silicon. Those wafers serve as the basic building block of integrated circuits (IC), where the innate conducting properties of the elemental metal create the communication pathways for all modern computers and electronics.

Yet another technology in which silicon plays a key role is in the manufacture of photovoltaics (PV). In this growing alternative energy application, silicon-wafer-based solar cells are used to convert photons from the sun into earth-bound electricity. Solar energy is seen by many as a power source that has great potential. However, solar manufacturers must find ways to decrease the cost per unit of power generated before the technology will be truly competitive with more mature fossil-fuel technologies.

“Depending on the price of polysilicon, about 30% of the final sale price of a solar cell is a function of the cost of the silicon alone,” says Dr. Julien Givernaud, a research engineer at EMIX, part of the French subsidiary of Grupo FerroAtlántica. Givernaud works on the optimization of the inductive cold crucible and associated equipment used to purify silicon for photovoltaics. “Lowering silicon production costs while increasing its purity is critically important in this industry.”

MANUFACTURING PV-QUALITY SILICON

In nature, silicon is the second most abundant element by mass in the earth’s crust. For photovoltaic applications, metallurgical silicon (which is 99.9% pure) must be processed into a higher-purity grade containing no more than one part-per-million impurity (99.9999%). Purity is important because it directly influences the amount of electricity a solar cell can produce from incoming sunlight—a measure called the photovoltaic conversion efficiency.

There are a number of competing manufacturing processes that transform silicon from its natural state to solar-cell ready. “Our continuous cold crucible casting, or 4C process, is a very innovative method for manufacturing PV-quality silicon,” says Givernaud, who uses the COMSOL Multiphysics® software to optimize production parameters. The company holds several patents and an exclusive worldwide operating license for the technology.

In the 4C process, silicon feedstock is fed into a water-cooled crucible where it is inductively heated to its melting temperature of 1,414 °C. It is then electromagnetically mixed in the crucible where Lorentz forces prevent contact between the crucible and the silicon melt, and the strong stirring homogenizes species concentrations at the solidliquid interface, enhancing crystallization conditions.

This results in high purity (see Figure 1).

Following mixing, the melt is then “pulled down” through the open-bottom crucible, where it cools and solidifies using a carefully controlled annealing process.

The continuously produced silicon rod is next sawed

into ingots, which are sold to PV manufacturers who, in turn, slice them into the 200-micrometer-thick sections used to make solar cells.

SIMULATION IMPROVES PHOTOVOLTAIC PRODUCTION EFFICIENCY

While relatively simple in concept, EMIX’s 4C process involves numerous manufacturing variables. This is where simulation comes in. Givernaud has performed countless calculations using simulation to examine, for example, the cooling method, the pull rate, crucible and coil shapes, and the characteristics of the furnaces. He has also analyzed the effect of the

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FIGURE 1. The schematic illustrates the cold crucible continuous casting (4C) process used to make silicon for photovoltaic applications. Silicon stock is fed into the system’s hopper at the top, then heated, cooled, and cut into ingots.

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INDUCTIVE COLD CRUCIBLE OPTIMIZATION | PHOTOVOLTAIC MATERIALS electromagnetic field, the shape of the solid-liquid interface, and the effect of elastic stresses on crystallization behavior.

Engineers at EMIX have been using multiphysics simulation for eight years—almost as long as they have been in the PV silicon business—to evaluate the production process.

“COMSOL Multiphysics is easier to use than the FEA tool in my previous job,” says Givernaud. “I create all of my geometries –JULIEN GIVERNAUD, RESEARCH ENGINEER AT EMIX directly in COMSOL. The model is very easy to mesh. It’s simple to switch between physics, and the solver is very fast and efficient. All-around, it’s an intuitive and powerful tool.”

Givernaud’s most recent modeling studies have involved both multiscale electromagnetic and 3D continuous casting simulations. His electromagnetic simulations permitted the estimation of inductance and impedance, as well as the optimization of the crucible design to improve electrical efficiency (see Figure 2). The continuous casting simulations allowed for the input of parameters such as electromagnetic power, crystallization rate, height of the crucible cooling zone, and after-heater temperatures. The combined results of these studies have led to a compromise between high production rates and low stresses in the ingots.

In the various simulations, the Heat Transfer in Fluids and Laminar Flow interfaces in COMSOL were used to calculate phase change in the silicon as it solidified in the crucible. Calculations for a cylindrical test crucible, when validated, will be applied to a larger crucible utilized in the commercial process.

“There has been very good agreement between our simulations and experiments for the pilot process,” says Givernaud. “Simulation helped us to reach good crystallization parameters, improve the electrical efficiency of the industrial size crucible, and reduce the number of tests on the pilot furnace.” He further adds that the latest series The R&D team at EMIX stands in front of a silicon production of simulations have, in theory, demonstrated energy savings furnace (from left to right): Julien Givernaud, Elodie Pereira, of approximately 15% and pulling-rate increases of about Nicolas Pourade, Florine Boulle, Alexandre Petit.

30%, which makes the 4C method far more productive than other standard silicon crystallization processes.

Industry-wide, manufacturers are striving to reduce silicon-wafer cost and improve purity for PV applications. Increased share in a growing solar marketplace will be the reward for the companies that develop the most commercially viable solutions. “Multiphysics simulation has helped us to identify some processes that will be tested soon on the industrial scale,” says Givernaud, who expects that EMIX will break new ground with innovations the company FIGURE 2. The model of the cold crucible has been used to predict the electromagnetic heating of the crucible (left) and molten silicon (center) and the triple-point liquid/solid/gas interface has been working on.

“COMSOL Multiphysics is easier to

use than the FEA tool at my previous job…All around, it’s an intuitive and powerful tool.”

(right) where red/yellow represents the melt and blue/green represents the solid phase.

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TNO, NETHERLANDS

VIRTUAL MATERIAL DESIGN IN 3D PRINTING MAKES HEADWAY WITH MULTISCALE MODELING Researchers at the Netherlands Organization for Applied Scientific Research (TNO) are using multiphysics simulation, multiscale modeling, and topology optimization to explore multimaterial 3D printing.

by LEXI CARVER In recent years, 3D printing (additive manufacturing) has become a major player in research, design, and manufacturing work. Now the technology is also showing promise in the realm of material design. It will soon be commonplace to create prints with multiple materials and varying properties over a single object—a capability that will create a wealth of new applications with integrated products featuring highly tailored material properties.

Additive manufacturing often uses small periodic microstructures in a repeating pattern to create the shape being built. A single microstructure is called a unit cell, and these may be as simple as triangles or honeycombs, or more complicated, with cross-struts and multiple voids between walls. Recent developments in 3D printing indicate that capabilities for multimaterial printing at the microlevel, where these microstructures can be combined and tailored to the designer’s needs, are rapidly expanding. This kind of fine control will allow engineers to choose the proportion and arrangement of each material included, giving them the freedom and flexibility to “design” performances that are impossible to achieve with a single material.

Researchers at the Netherlands Organization for Applied Scientific Research (TNO) have begun investigating virtual material design, relying on multiphysics simulation and multiscale modeling to determine how specific properties could be effectively designed into a 3D-printed object. Work at the research institute spans many subjects, including safety and security,

THE STORY OF STRESS, STRAIN, AND STIFFNESS IN ANISOTROPIC MATERIALS

Anisotropic materials behave differently depending on the direction they are loaded; however, with current methods of material production, control over the anisotropy is limited. Hence, any advantages are difficult to exploit for product design purposes.

Marco Barink, researcher at TNO, set out to develop a procedure for designing manufacturable anisotropic structures using stiffness and topology optimization techniques. He began using the COMSOL Multiphysics® software to investigate a single unit cell intended to have twice the stiffness in one planar direction as the other (see Figure 1).

“We were aiming for a desired stiffness matrix, so we applied a strain in COMSOL and then optimized it to find the desired stress,” he explained. “We can tell COMSOL to make the material twice as stiff in one direction as another, and analyze the material behavior for a given geometry.” He verified the simulation results using a printed sample that he tested for the expected material behavior.

After determining that his results were accurate, he performed a second optimization study for a highly anisotropic material. In this case, the simulation could control not only the spatial distribution of the material, but also the orientation of

FIGURE 1. Top: Geometry of a unit cell. Middle: Simulation results showing mechanical stress for an optimized design with one planar direction having half the stiffness of the other. Bottom: 3D-printed samples.

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energy, and manufacturing—the techniques used for optimizing material and topology in 3D-printed designs have been extended to their other areas of research, such as lightweight mechatronics, free-form solar cells, and lighting products.

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MULTIMATERIAL 3D PRINTING | MATERIALS SCIENCE

FIGURE 2. Barink’s simulation results showing optimized material composition (with three materials) for the desired anisotropic thermal conductivity. The simulation shows regions of high conductivity (white), low conductivity (orange), and a nonconductive material and voids (red). Several unit cells are arrayed periodically. the anisotropic fibers.

With the larger goal in mind of designing properties beyond those available in a single material, the next step was to extend the simulation to structures comprising different material combinations, or multimaterials. Barink defined an anisotropic multimaterial cell in COMSOL, then optimized the local distribution of each material over a whole structure composed of a pattern of these cells (see Figure 2). He used the software to adjust the composition and arrangement until he reached the desired overall thermal conductivity.

MULTISCALE MODELING AND COMPUTATIONAL HOMOGENIZATION

Each of these unit cells, in reality, would only be a tiny region in a final piece.

After optimization at the microlevel, the TNO team began to study material optimization for larger-scale devices.

“We’ve found that this microscale strategy works well for relatively small volumes,” said Erica Coenen, a research engineer at TNO. “However, to design real-life products, these need to be scaled up while maintaining feasible computation times. This is where so-called multiscale modeling comes in, giving the designer the tools to efficiently simulate at both the micromaterial scale and the product scale simultaneously.”

Coenen implemented tools in

COMSOL to extract parameters for the effective structural behavior of a single multimaterial cell. This effective behavior is used in a full-scale model, or macromodel, of a whole device.

“We succeeded in creating a fullycoupled multiscale simulation—the macromodel contains homogeneous properties without any substructure details, and the micromodel contains the heterogeneous multimaterial microstructure. Many micromodels run within a single macromodel,” she explained. “We can consider multiple micromodels at once, solving for highly nonlinear and temperature-dependent behavior, based on local conditions from the macromodel.”

Coenen and Barink applied a simplified version of this method to one of the major research topics at TNO, the development of large, flexible organic LEDs (OLEDs), which require the deposition of organic semiconductors onto flexible substrates. For good light homogeneity, these devices require careful design of the metal grids used in their transparent front-end electrodes; visible differences in light output create lighter and darker areas, which are undesirable for a final product.

But directly modeling an OLED with a metal grid proved challenging in the past, due to large differences in the dimensions of different components.

The honeycomb shapes that form the grid are only a few millimeters wide, and their metal edges 10 – 100 microns thick. Against the backdrop of the

FIGURE 3. Simulation results in the COMSOL® software showing the light output of an OLED. Top: Model including the hexagonal grid. Bottom: Macromodel with homogenized material properties. comparatively large complete OLED (tens of centimeters wide), the different length scales are difficult to account for in a single model.

“Multiscale modeling is really the way to go forward,” Barink commented.

With a new COMSOL study, they analyzed the grid shape to determine the ideal layout for improving light distribution. Combining a macromodel of the entire OLED with a micromodel of the honeycomb grid, they solved for effective light output and optimized the spacing and honeycomb dimensions (see Figure 3). Their updates to the existing

FIGURE 4. Left: Meshed model of a cell optimized for metal 3D printing.

Right: Overview of the homogenized material properties for different cell designs.

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MULTIMATERIAL 3D PRINTING | MATERIALS SCIENCE design resulted in a 12% improvement in homogeneity without compromising efficiency in the OLED.

BRINGING IT ALL TOGETHER: FROM SINGLE CELL TO COMPLETE PART

Coenen and Barink had demonstrated that topology optimization is a powerful tool for generating designs for additive manufacturing, given the capabilities of developing products that cannot be manufactured using conventional techniques. But even such a flexible manufacturing technology has some limitations. In one form of 3D printing called selective laser melting (SLM), the printer melts layers of powder into the desired shape. Unused powder must be removed from the object afterward, and large overhangs are usually avoided in SLM designs as they may warp. Therein lies a potential conflict: What happens when topology optimization creates an idealized design containing closed voids or large overhangs?

“To circumvent this issue, our engineers came up with a few unit cells of different densities,” Barink remarked. “These cells are designed to be stiff, always printable, and contain holes so that the powder can be removed. Different unit cells combine to create the desired overall properties.” They then used COMSOL to analyze the relationship between material density and mechanical stiffness (see Figure 4).

At the device level, it is not possible to handle a model with thousands of small 3D unit cells. So they combined their tested techniques: stiffness homogenization for each unit cell type followed by topology optimization at a larger level. “The homogenized properties of each unit cell serve as a separate material in the topology optimization at the device level,” Barink continued.

For a concrete, less expensive example than a metal print, they applied the whole procedure to a polymer hammer handle (see Figure 5). The final design contains a combination of the different cell types, optimized by the software for the correct stiffness with minimal material use. “The hammer handle served as a demonstration of the power and

versatility of the whole procedure, going from design to final product,” Barink said. “From the design of unit cells, homogenization, topology optimization, generating printer input, and finally, printing, we have developed a good technique for designing a complete device with all the microlevel features. When applied to SLM designs, the techniques will address the typical production issues faced in metal printing, where stronger and more high-tech products are designed.”

The team at TNO had begun with a single cell and successfully built their way to anisotropic multimaterial microstructures. The application of their techniques to multiple areas of research at TNO demonstrated the power of combining simulation and multiscale modeling with innovative product development. This glimpse into the future, where multimaterial design may become the norm in additive manufacturing, would not have been possible without simulation.

Marco Barink (left) and Erica Coenen (right) standing with the 3D printer at TNO.

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FIGURE 5. Left: Topology optimization result in the COMSOL® software. Center: The optimized hammer handle, printed in nylon. Right: Close-up of the pattern containing three different cell types: most dense cells with small holes near the top, least dense cells toward the bottom, and a few intermediate shapes in between.

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NEWTECNIC, UK

OPTIMIZING THE PERFORMANCE OF COMPLEX BUILDING FAÇADES Using multiphysics simulation to understand the interaction between environmental, geometrical, and structural variables, engineers at Newtecnic ensure that innovative building façades are both beautiful and buildable.

by JENNIFER HAND

Federation Square, Melbourne, Australia cladding affect the integrity of the insulation, there are numerous challenges that can be resolved with the help of simulation.

BEYOND CONCEPTUAL DESIGN WITH SIMULATION

FIGURE 1. Heydar Aliyev Cultural Center, Baku, Azerbaijan.

Dynamic, textural, and symbolic; whether they ambitiously defy gravity or grow organically from the landscape, iconic buildings frequently involve complex façades. Designed not only to protect, they also regulate variables such as thermal and visual comfort.

A specialist in this area, Newtecnic designs and analyzes façade systems for use in high-profile public projects and regularly works with Zaha Hadid Architects, a practice recognized for its bold and fluid architectural forms.

Newtecnic’s founders and current directors, Andrew Watts and Yasmin Watts, are known for their work on prominent projects including the iconic Federation Square (Melbourne, Australia) and more recently, the Heydar Aliyev Cultural Center in Baku, Azerbaijan (see Figure 1).

Bespoke is the norm for Newtecnic, and every project requires thinking

that goes far beyond conceptual design alone. Architects provide an artistic view and perhaps some surface modeling of a building design, then Newtecnic engineers build up the façade in layers, making sure that the design retains its creativity while also ensuring its structural integrity.

“Our clients want viable and economic design solutions that meet the required performance targets, can withstand environmental effects, and are easy to maintain,” says Carmelo Galante, head of Research and Development at Newtecnic. “A key aspect of our work is therefore to describe the physical behavior of the façade systems we design.”

From solar studies that allow optimization of the shading design in order to reduce cooling loads and maximize visual comfort, to the way in which fixing brackets for rainscreen

The COMSOL Multiphysics® software has become a key tool for Newtecnic.

Galante explains: “We can do everything within one simulation software. I use COMSOL to study the 3D thermal bridging effect—the way in which highly conductive materials penetrate insulation—on the overall energy efficiency of the build-up, evaluate the maximum temperature of components, and suggest the most suitable product or material. I can evaluate cladding pressures on the building structure for schematic design stages and study more complex façades in which mechanical and natural ventilation are present at the same time. I can also evaluate how

FIGURE 2. Rendering of a single shell shown from two different angles, many of which will be part of the building.

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THERMAL BRIDGES | BUILDING PHYSICS

“Simulation minimizes

construction costs by allowing contractors to see exactly what they are required to build.”

–FABIO MICOLI, ASSOCIATE DIRECTOR AT NEWTECNIC

FIGURE 3. Highlighted view of the rainscreen system with fixing brackets.

FIGURE 4. Simulation results showing isotherms and temperature profile in oC of a section taken through a bracket. different design configurations would affect the hygrothermal performance of a façade system.”

Using the CAD import functionality available in the COMSOL® software, Galante often imports complex geometries, mainly from Autodesk® AutoCAD® software and Rhinoceros® software. The use of Autodesk® Revit® software is continuously increasing at Newtecnic, and he considers the new LiveLink™ for Revit®, an addon to COMSOL that allows users to interface their simulations with the Revit environment, to be a powerful asset. Galante also combines the use of COMSOL with parametric design tools such as the programming language Grasshopper®, which is used to build and analyze complex geometries by means of generative algorithms.

One current project at Newtecnic involves designing the façade system for a high-profile private building comprising a series of self-supporting

to evaluate three areas of interest: those influenced by one bracket, those influenced by two or more brackets, and those not influenced at all (these areas are shown in Figure 5).

Galante was then able to prepare an accurate geometry for the system, including all the components of the build-up. “It is a real advantage to be able to combine two tools,” says Galante. “Grasshopper® allows me to investigate the geometry on a very large scale—that of the entire building—then I move back to COMSOL with this information and create a very detailed 3D model to capture the real physics of the system.” Using this approach, Galante was able to conduct a 3D analysis to study the thermal bridge effect in the bracket and surrounding building (see Figure 6) and compute the global heat transfer coefficient (U-value) of the façade.

“Using multiphysics simulation allows me to develop a better understanding of the real situation,” explains Galante.

FIGURE 5. Model of one of the shells shown in Figure 2 with areas highlighted that are influenced by one bracket, two brackets, or not influenced by any bracket.

Autodesk, the Autodesk logo, AutoCAD, and Revit are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and/or other countries.

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concrete shells ranging from 10 to 80 m in length and reaching heights of up to 30 m (see Figure 2).

The concrete shells are clad with a rainscreen façade system made out of ceramic panels that are doubly curved in order to accurately reproduce the building geometry. Each panel is supported at its corners by adjustable fixing brackets made out of stainless steel. These brackets are attached to the concrete structure through four postdrilled anchorages, as shown in Figure 3.

As the brackets penetrate the insulation layer and have a much higher thermal conductivity than the concrete structure, they create thermal bridges through the façade envelope, significantly reducing its thermal performance.

By conducting a simplified 2D study in COMSOL, Galante studied how the thermal bridge effect created by the brackets influenced the temperature distribution in the façade (see Figure 4).

The results from the simulation were entered into a Grasshopper® script

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THERMAL BRIDGES | BUILDING PHYSICS

FIGURE 6. Left: 3D model of the brackets and surrounding insulation built in Rhinoceros® software and imported into the COMSOL Multiphysics® software. Center: COMSOL® software model showing the temperature profile in oC in the area influenced by the bracket. Right: Stainless steel bracket.

“I can combine fluid flow with heat transfer by conduction, convection, and radiation, meaning that I can thoroughly evaluate the interplay of different physical effects and confirm the performance of different structures and materials.”

RESPONDING TO DESIGN CHANGES

Newtecnic’s engineers have to respond to continually changing designs, and need to be able to validate any design updates. “Simulation allows us to do that,” observes Galante. “We can demonstrate exactly what effect a design change will have, whether it relates, for example, to energy efficiency, structural performance, corrosion, or the lifecycle of a component.”

For Newtecnic director Andrew Watts, it is all about answering questions such as “Is it worth changing this to make something else work?” or “If we have to change it, how much do we have to change it by?” He comments: “With simulation, we can move away from the traditional building philosophy of studying individual components that only perform one function and can instead think in terms of multifunctional components, and of the building as a whole.”

Simulation is used to conduct analyses for every component of a building, and these results are fully integrated with drawings so that budget estimates are both clear and comprehensive. Fabio Micoli, Associate Director at Newtecnic,

notes the value of delivering live feedback to clients.

“Simulation minimizes construction costs by allowing contractors to see exactly what they are required to build, thereby reducing the need for contingency budgets or time for unresolved design issues and allowing the construction team to concentrate on meeting project deadlines.”

CONTINUING IMPROVEMENT

“The digital tools that we use, such as simulation software, enable us to explore new possibilities and improve our design processes,” Galante says. He and his colleagues can see potential

for expanding the use of simulation at Newtecnic, including using the new Application Builder, now part of the COMSOL Multiphysics® version 5.0. As Micoli notes, “We could, for example, enhance communication with clients by creating an application that allows an architect to modify different parameters and see exactly how changes would affect their design without knowing the underlying multiphysics simulation details.”

The bottom line is that with simulation, a better understanding of building performance can be delivered to Newtecnic’s clients than ever before, ensuring that an innovative architectural design puts its best face forward.

Carmelo Galante (left), Andrew Watts (middle), and Fabio Micoli (right) discuss a recent project at the Newtecnic office in London, UK. COMSOL NEWS

Grasshopper and Rhinoceros are registered trademarks of Robert McNeel & Associates.

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BRÜEL & KJÆR, DENMARK

PRECISION PERFORMANCE: THE PURSUIT OF PERFECT MEASUREMENT

Researchers at Brüel & Kjær are using simulation to achieve new levels of precision and accuracy for their industrial and measurement-grade microphones and transducers.

by ALEXANDRA FOLEY

FIGURE 1. Left: Photo of a 4134 microphone including the protective grid mounted above the diaphragm. Right: Sectional view of a typical microphone cartridge showing its main components.

There will never be a perfect measurement taken or an infallible instrument created. While we may implicitly trust the measurements we take, no measurement will ever be flawless, as our instruments do not define what they measure. Instead, they react to surrounding phenomena and interpret this data against an imperfect representation of an absolute standard.

Therefore, all instruments have a degree of acceptable error—an allowable amount that measurements can differ without negating their usability. The challenge is to design instruments with an error range that is both known and consistent, even over extended periods of time.

Brüel & Kjær A/S has been a leader in the field of sound and vibration measurement and analysis for over 40 years. Their customers include Airbus, Boeing, Ferrari, Bosch, Honeywell, Caterpillar, Ford, Toyota, Volvo, RollsRoyce, Lockheed Martin, and NASA, just to name a few.

Because industry sound and vibration

DESIGNING AND MANUFACTURING ACCURATE MICROPHONES

Brüel & Kjær develops and produces condenser microphones covering frequencies from infrasound to ultrasound, and levels from below the hearing threshold to the highest sound pressure in normal atmospheric conditions. The range includes working standard and laboratory standard microphones, as well as dedicated microphones for special applications.

Consistency and reliability is a key

FIGURE 2. Geometry plot of the 4134 condenser microphone. The figure shows the mesh used in the reduced sector geometry, representing 1/12 of the total geometry. parameter in the development of all of Brüel & Kjær’s microphones.

“We use simulation to develop condenser microphones and to ensure that they meet relevant International Electrical Commission (ICE) and International Organization for Standardization (ISO) standards,” says Erling Olsen, development engineer in Brüel & Kjær’s Microphone Research

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challenges are diverse—from traffic and airport noise to car engine vibration, wind turbine noise, and production quality control, Brüel & Kjær must design microphones and accelerometers that meet a variety of different measurement standards.

In order to meet these requirements, the company’s R&D process includes simulation as a way to verify the precision and accuracy of their devices and test new and innovative designs.

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PRECISION TRANSDUCERS | ACOUSTIC ENGINEERING and Development department.

“Simulation is used as part of our R&D process, together with other tools, all so that we know that our microphones will perform reliably under a wide range of conditions. For example, we know precisely the influence of static pressure, temperature and humidity, and the effect of other factors for all of our microphones—parameters that would have been very difficult to measure were it not for our use of simulation.”

The Brüel & Kjær Type 4134 condenser microphone shown in Figure 1 is an old microphone that has been subject to many theoretical and practical investigations over time.

Therefore, the 4134 microphone has been used as a prototype for developing multiphysics models of Brüel & Kjær condenser microphones. To analyze the microphone’s performance, Olsen’s simulations include the movement of the diaphragm, the electromechanical interactions of the membrane deformations with electrical signal generation, the resonance frequency, and the viscous and thermal acoustic losses occurring in the microphone’s internal cavities.

MICROPHONE MODELING

When sound enters a microphone, sound pressure waves induce deformations in the diaphragm, which are measured as electrical signals. These electrical signals are then converted into sound decibels. “Modeling a microphone involves solving a moving mesh and tightly coupled mechanical, electrical, and acoustic problems—something that could not be done without multiphysics,” says Olsen. “The models need to be very detailed because in most cases, large aspect ratios (due to the shape of the microphone cartridges) and small dimensions cause thermal and viscous losses to play an important role in the microphone’s performance.”

The model can also be used to predict the interactions that occur between the backplate and diaphragm. Among other things, this influences the directional characteristics of the microphone. “We used the simulation to analyze the bending pattern of the diaphragm,” says

Olsen. For simulations such as thermal stress and resonance frequency, model symmetry was used to reduce calculation time (see Figure 2). The reduced model was also used to analyze the sound pressure level in the microphone for sounds that are at a normal incidence to the microphone diaphragm (see Figure 3). However, when sound enters the microphone with non-normal incidence, the membrane is subjected to a nonsymmetrical boundary condition.

This requires a simulation that considers the entire geometry in order to accurately capture the bending of the membrane (see Figure 4).

Simulation was also used to determine the influence of the air vent in the microphone for measuring low-frequency sounds. “We modeled the microphone with the vent either exposed to the external sound field, outside the field (unexposed), or without a vent,” says Olsen. “While the latter would not be done in practice, it allowed us to determine the interaction between the vent configuration and the input resistance results for different low-frequency behaviors. This is one of the most important things about simulation: We can make changes to the parameters of a model that move away from already manufactured devices, allowing us to test other designs and explore the limits of a device (see Figure 5).”

FIGURE 3. Representation of the sound pressure level below the diaphragm for normal incidence, calculated using the sector geometry. The membrane deformation is evaluated at f = 20 kHz.

FIGURE 4. Simulation results showing the membrane deformation calculated for non-normal incidence at 25 kHz. Since the deformation is asymmetrical, this is calculated using the full 3D model.

FIGURE 5. In the no-vent configuration, the sensitivity increase is due to the fact that the sound field becomes purely isothermal inside the microphone at very low frequencies. In the vent outside the sound field configuration, the curve initially follows the no-vent curve, but sensitivity increases further as the vent becomes a pressure release on the back of the diaphragm.

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PRECISION TRANSDUCERS | ACOUSTIC ENGINEERING With simulation as part of the R&D process, Olsen and his colleagues are able not only to design and test some of Brüel & Kjær’s core products, but devices can also be created based on a specific customer’s requirements.

“With simulation, we can pinpoint approaches for making specific improvements based on a customer’s needs. Although microphone acoustics are very hard to measure through testing alone, after validating our simulations against a physical model for a certain configuration, we are able to use the simulation to analyze other configurations and environments on a case-by-case basis.”

VIBRATION TRANSDUCER MODELING

Søren Andresen, a development engineer with Brüel & Kjær, also uses simulation to design and test vibration transducer designs.

“One of the complications with designing transducers for vibration analysis is the harsh environments that these devices need to be able to withstand,” says Andresen. “Our goal was to design a device that has so much built-in resistance that it can withstand extremely harsh environments.”

Most mechanical systems tend to have their resonance frequencies confined to within a relatively narrow range, typically between 10 and 1000 Hz. One of the most important aspects of transducer design is that the device does not resonate at the same frequency as the vibrations to be measured, as this would interfere with the measured results. Figure 6 shows the mechanical displacement of a suspended vibration transducer, as well as a plot of the resonance frequency for the device.

“We want the transducer to have a flat response and no resonance frequency for the desired vibration range being measured,” says Andresen. “We used COMSOL to experiment with different designs in order to determine the combination of materials and geometry that produces a flat profile (no resonance) for a certain design. This is the region in which the transducer will be used.”

When designing the transducer, a low-pass filter, or mechanical filter, can be used to cut away the undesired signal caused by the transducer resonance, if any. These filters consist of a medium, typically rubber, bonded between two mounting discs, which is then fixed between the transducer and the mounting surface.

“As a rule of thumb, we set the upper frequency limit to one-third of the transducer’s resonance frequency, so that we know that vibration

components measured at the upper frequency limit will be in error by no more than 10 to 12%,” says Andresen.

AS ACCURATE AND PRECISE AS POSSIBLE

While it may not be possible to design a perfect transducer or take an infallible measurement, simulation brings research and design teams closer than ever before by allowing them to quickly and efficiently test new design solutions for many different operating scenarios.

“In order to stay ahead of the competition, we need knowledge that is unique,” says Andresen.

“Simulation provides us with this, as we can make adjustments and take virtual measurements that we couldn’t otherwise determine experimentally, allowing us to test out and optimize innovative new designs.”

“With simulation,

we can pin-point approaches for making specific improvements based on a customer’s needs.”

–ERLING OLSEN, DEVELOPMENT ENGINEER AT BRÜEL & KJÆR

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FIGURE 6. Simulation results of a suspended piezoelectric vibration transducer. Top: Mechanical deformation and electrical field in the piezoelectric sensing element and seismic masses. Bottom: Frequency-response plot showing the first resonance of the transducer at around 90 kHz. This device should only be used to measure objects at frequencies well below 90 kHz.

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NATIONAL RENEWABLE ENERGY LABORATORY, CO, USA

MAKING BIOFUEL A COSTEFFECTIVE, RENEWABLE SOURCE OF ENERGY

Researchers at the National Renewable Energy Laboratory are using multiphysics simulation to better understand and optimize the conversion process for plant-derived biofuels.

by JENNIFER SEGUI Biofuels could potentially replace fossil fuels for many applications, offering an alternative source of energy to heat buildings, generate electricity, and keep the transportation industry moving.

There are many benefits to producing biofuels from plant-based materials, generally referred to as biomass. Such fuels are renewable, clean-burning, and carbon-neutral, producing no more carbon dioxide than is sequestered by its original plant source. However, biofuel availability is still fairly limited for its most common use—in vehicles. As of 2014, the U.S. Energy Information Administration reports that only 2% of retail fueling stations were offering the ethanol-based fuel E85.

The production process itself poses an important economic barrier to the widespread use of biofuels. Research at the National Renewable Energy Laboratory (NREL), supported by the Computational Pyrolysis Consortium, is directed toward gaining a better understanding of the physical processes behind biofuel conversion by developing computational models that feature the most accurate representation of biomass particle geometry to date. Such a model could then be used to improve reactor design and operation as required for the mass production of biofuel.

This work can ultimately make biofuel use more costeffective and competitive with traditional nonrenewable fuels, some of which will be depleted in mere decades.

FIGURE 1. In preparation for pyrolysis, the woody biomass shown at left has been milled and may also undergo additional chemical treatment. Several physical processes including heat transfer, mass transfer, chemical reactions, and phase change must be taken into account to develop a complete model of pyrolysis, shown at right. The flask in the photo collects the condensed bio-oil vapors resulting from pyrolysis in a pre-commercial reactor. Photo credits: Warren Gretz, NREL 05756 (left) and Phil Shepherd, NREL 03677 (right).

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COMPUTATIONAL PYROLYSIS | BIOFUELS

“Since COMSOL

has geometry tools, physics, meshing, and solvers already implemented, we can spend more time making the biomass model geometry really accurate.”

FIGURE 2. Left: A scanning electron micrograph confirms the shape and structure of a hardwood biomass particle. Right: A confocal scanning laser micrograph of a particle cross section shows the microstructure.

PRODUCING FUEL FROM PLANTS

Thermochemical processes such as pyrolysis, which is shown in Figure 1, use exposure to high temperatures to break down and convert biomass particles to liquid biofuels that can support many everyday life activities. Improving fast pyrolysis, a pre-commercial thermochemical conversion route often used for woody biomass, is one objective of the research program at NREL, and is described in more detail in the sidebar below.

Peter Ciesielski, a research scientist at NREL, and his colleagues are using multiphysics simulation to gain insight into the fundamental processes behind biomass conversion via pyrolysis, starting with investigating heat and mass transfer.

Efficient heat and mass transfer through biomass particles

–PETER CIESIELSKI, RESEARCH SCIENTIST AT NREL

minimizes char formation and accelerates favorable reactions by facilitating the penetration of conversion catalysts and the escape of desired products. Ciesielski’s work considers the effect of size, shape, and internal microstructure of biomass particles, which is determined by the species of wood and by the milling process used prior to pyrolysis.

AN ACCURATE MODEL OF BIOMASS

Computational studies designed to understand and optimize the biofuel conversion process have always used simplified biomass particle geometry that ignored internal microstructure.

Ciesielski’s research aims to provide insight into the heat and mass transfer in biomass by developing a model in

COMPUTATIONAL PYROLYSIS CONSORTIUM Ciesielski’s work, supported by the Computational Pyrolysis Consortium and funded by the U.S. Department of Energy, is a collaborative effort between researchers at NREL, Oakridge National Laboratory (ORNL), and the National Institute of Standards and Technology (NIST). The collaboration brings together experts in computational modeling, biomass conversion, reactor design, and materials characterization to optimize biofuel production via pyrolysis.

To appreciate the significance of pyrolysis—first think about a fire, but take away the flame. Pyrolysis is a thermochemical conversion route that causes decomposition of biomass via exposure to high temperatures and in the absence of oxygen.

Without oxygen, there is no combustion or flame. The result of pyrolysis is char, a liquid product often referred to as bio-oil, and gaseous products of the chemical reaction. Biofuels are produced from further refinement of the bio-oil.

Fast pyrolysis research at NREL takes the process one step further by using an extremely high rate of heat transfer to break down biomass, where internal temperatures reach upwards of 500˚C within 1 second.

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Peter Ciesielski, a research scientist at NREL, is pictured next to the scanning electron microscope used to acquire images of wood biomass for his work published in Energy & Fuels1.

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COMPUTATIONAL PYROLYSIS | BIOFUELS the COMSOL Multiphysics® software that takes internal microstructure into account. “Since COMSOL has the geometry tools, physics, meshing, and solvers already implemented, we can spend more time making the biomass model geometry really accurate,” explains Ciesielski.

In order to generate 3D models of biomass for use in COMSOL simulations, a confluence of imaging methods was used to characterize the external morphology and size distribution as well as the internal microstructure of each type of biomass. Examples of images that were acquired for this study are shown in Figure 2.

A solid geometry was generated using the external and internal dimensions of biomass particles, determined from the images, as input to a series of Boolean geometry operations in COMSOL. The complete geometry consists of two domains, as shown in Figure 3.

SIMULATING PYROLYSIS: HEAT AND MASS TRANSFER

Biomass decomposition via fast pyrolysis starts with the application of high temperatures (about 500oC) to an oxygen-free reaction vessel for a few seconds. Applying these conditions, the Conjugate Heat Transfer interface in COMSOL was used to simulate heat transfer between the outer fluid domain shown in Figure 3a, consisting of nitrogen gas, and the biomass particle. Heat transfer in the fluid domain is predominately by convection, whereas at the interface and through the biomass particle, heat transfer is by conduction only.

The simulations were run on a high-performance computing (HPC) cluster using one or two compute nodes each consisting of 24 Intel® Xeon® Ivy Bridge processors with 64 GB of RAM. The results in Figure 3b show the temperature distribution in a hardwood biomass particle 0.5 seconds into a transient simulation of conjugate heat

transfer. For a given particle size, shape, and microstructure, it is possible to determine the amount of time required for the entire particle, particularly the center, to reach optimal temperatures for decomposition.

In a separate simulation, the diffusion of sulfuric acid, a chemical used to pretreat biomass prior to its conversion to biofuel, was evaluated. The Transport of Diluted Species interface was used for transient simulations of mass transport in the microstructure and solid particle geometries where the surrounding fluid in this case was water.

The results from both the heat and mass transfer studies indicate that a solid model, particularly a spherical one, may not offer sufficient accuracy to evaluate and optimize biofuel conversion processes and that the use of a microstructured model is justified.

INPUT FOR LARGE-SCALE REACTOR DESIGN

While the present study focuses on heat and mass transfer in biomass, rapid phase transitions and chemical reactions are critical to fully understand and optimize biofuel production via fast pyrolysis. Ciesielski’s ongoing work involves adding these to his simulations, the ability to do so being an important reason why COMSOL was chosen.

Ultimately, however, the team has bigger plans for the computational model. By performing simulations to gain a fundamental understanding of transport in biomass, effective correlations for low-order models can be determined for a range of process parameters and biomass feedstocks. These correlations can be used to optimize the design and operation of large-scale reactors for mass production of biofuel, making the process more efficient and cost-effective.

REFERENCES 1

P. N. Ciesielski, et. al., Energy Fuels, 2015, 29(1), pp 242-254.

FIGURE 3. Left: COMSOL® software model geometry featuring a fluid domain surrounding a hardwood biomass particle. Right: The temperature distribution from a transient simulation of conjugate heat transfer is shown.

COMSOL NEWS

Intel and Xeon are trademarks of Intel Corporation in the U.S. and/or other countries

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VERYST ENGINEERING, MA, USA

SIMULATION SOLVES THE MYSTERY BEHIND AN ELEVATOR ACCIDENT

While we can easily picture simulation as an integral part of product design related activities, other uses are equally important: Field failure analysis and forensic examination are two examples. Veryst Engineering used multiphysics simulation to investigate and determine how an elevator brake failed prematurely.

by STUART BROWN, NAGI ELABBASI, & MATTHEW HANCOCK, VERYST ENGINEERING In 2007, an elevator began moving upwards while passengers were exiting, trapping and injuring an occupant. A drum brake intended to hold the elevator stationary failed, resulting in the unexpected movement.

Subsequent investigation revealed that a solenoid responsible for opening and closing the brake had deteriorated, causing the brake linings to drag on the drum and wear prematurely.

When the solenoid was not engaged, normal brake shoes would have pushed against the drum, preventing elevator motion. Excess brake shoe wear caused the brake to fail to hold, leading to the accident. Figure 1 shows a CAD model of the brake, where the brake arms are pivoted at the bottom and spring loaded to maintain contact with the drum.

Criminal charges were filed against the elevator maintenance firms, claiming that there was evidence in previous years that the solenoid was deteriorating and that repairs should have been performed. The question was not whether the solenoid had failed, but rather, how did it fail and at what rate—slowly or quickly?

If the failure were

rapid, it would have been unlikely that the accident could have been anticipated. However, if the failure involved a slow deterioration, perhaps the accident could have been prevented. Many possible theories of failure were suggested.

We at Veryst Engineering, a consulting firm based in Massachusetts, were hired to investigate the validity of the different failure theories, and simulation played a pivotal role in our investigation.

ANALYSIS OF SOLENOID FAILURE

After the accident, investigators discovered that the solenoid had approximately half the electrical resistance of an undamaged solenoid, and therefore, generated less force compared to an undamaged solenoid. Several theories were proposed to explain how this failure could have occurred.

One theory for slow failure was that thermal expansion and contraction within the solenoid due to resistive heating produced high stresses leading to slow, progressive cracking of the wires within the solenoid coil. Cracks would reduce the solenoid’s electromotive force (EMF), thereby leading to brake shoe dragging. In order to test this theory, we used the COMSOL Multiphysics® software to produce a coupled

thermomechanical stress analysis of the solenoid. The model demonstrated that the stresses were not large enough to produce cracking, therefore proving that expansion and contraction due to resistive heating was not the cause of the failure.

A second theory for slow failure was that the EMF itself generated high stresses in the coil, causing it to fail over an extended period of time. We tested this by performing a coupled electromechanical analysis, which is shown in Figure 2. COMSOL® software was used to calculate the Lorentz force within the solenoid coil, demonstrating that the force throughout

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FIGURE 1. Left: Brake CAD geometry. Right: Brake lining wear model setup showing the brake drum, arms and pivots, the opposing spring and solenoid forces, and the contact between brake linings and the drum.

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BRAKING SYSTEMS | FORENSIC ENGINEERING the coil was practically negligible.

In contrast, one theory for rapid solenoid failure stipulated that localized heating within the solenoid resulted in shorting between adjacent coil wires. While we did not analyze this theory directly, our analysis refuting the above slow failure theories narrowed the field of possible failure modes and lent support to the rapid failure scenario.

ANALYSIS OF RAPID BRAKE LINING WEAR

In addition to the solenoid failure analysis, we investigated the effect of a damaged solenoid on brake lining wear. Given FIGURE 2. Magnetic potential within solenoid component. that the solenoid involved in the accident could not generate the force of a normal solenoid, could the brake linings have also deteriorated so quickly? After the accident, investigators discovered that the brake lining wear was extensive, and assumed that this degree of wear had to have occurred gradually.

To test whether the extensive brake wear could have occurred swiftly given a damaged solenoid, we developed a COMSOL model of the brake to calculate the local brake lining wear. The model included the brake arm pivoting as well as the opposing forces of the springs and damaged solenoid. In addition, the model included data from the extensive wear experiments performed by investigators on prototype drum brake linings, which resulted in data correlating bulk lining wear rates to brake drum temperature.

We used this temperature-wear data combined with a wear rate model commonly used in the brake industry to develop a local wear rate model. The model was FIGURE 3. COMSOL Multiphysics® software model used to implemented using both the Structural Mechanics Module calculate brake lining wear. and user-defined differential equations defined on the brake lining surfaces. The contact boundary condition available in COMSOL provided the local contact pressure for the model, which was used to determine the local wear rate at each point along the brake linings. The predicted brake lining wear was in turn used to specify an offset from the original brake surface in the contact boundary condition, a valid assumption provided the amount of wear is small compared to the lining thickness. The input to the wear simulation was an assumed time history of drum temperature. We validated this wear modeling approach by simulating two mechanical wear problems: wear resulting from pin-on-disc contact and wear in automotive disk brakes.

FIGURE 4. Comparison of measured lining wear with The contact boundary condition within the Structural simulation prediction.

Mechanics Module and the ability to easily implement user-defined differential equations made programming the linings was entirely consistent with a rapid train of events, wear process remarkably straightforward and helped us to from the rapid deterioration of the solenoid to the rapid and avoid cumbersome methods such as mesh element deletion. extensive brake lining wear. This rapid failure theory provided This type of analysis would have been either impossible or an alternative, self-consistent, and scientifically sound prohibitively difficult using any other finite element package. explanation of the accident, involving no slow processes.

Figure 3 shows the finite element model used in the wear COMSOL Multiphysics was an essential contributor to this analysis. Figure 4 shows a comparison between the measured investigation, enabling us to quickly investigate different and predicted brake lining wear along the length of the scenarios by allowing us to readily import and handle brakes at the end of the test. The model also predicted different geometries, include multiple physics in a single how wear depth varied with time. The results of the wear simulation, and import and use experimental data with simulation indicated that a damaged solenoid could result in our simulations. The simulations provided an efficient and high drum temperatures, leading to rapid brake lining wear. systematic way to test and evaluate the failure scenarios, an In other words, the high amount of wear on the brake approach that no one else had tried.

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FRAUNHOFER ISE, GERMANY

BETTER WAYS TO HEAT AND COOL BUILDINGS

Multiphysics simulation helps researchers at the Fraunhofer Institute for Solar Energy Systems develop innovative adsorption-based chillers, heat pumps, and thermal storage units driven by solar, natural gas, and waste heat.

by GARY DAGASTINE The heating and cooling of buildings accounts for nearly 50 percent of energy consumption in Europe, spurring researchers to find alternatives to conventional technologies.

One enticing possibility is to use adsorption-based heating and cooling systems driven not by electricity, but by heat. Because heat could come from solar collectors, from waste heat generated by industrial facilities, or from combined heat and power units, this adsorption technology offers the possibility of significantly reducing electricity consumption and associated CO2 emissions.

The technology can be used not only as a highly efficient heating system that uses gas-fired heat pumps to multiply the heat delivered to a building, but also for the compact storing of energy for a long period of time.

In brief, heating and cooling systems based on this principle use a working fluid in an adsorption/ desorption cycle where the fluid’s state is altered from liquid to gas and vice versa numerous times (see the sidebar on page 37 for more details). With this technique, special heat exchangers can be built that act as

OPTIMIZING THERMAL TRANSFER AND STORAGE

The development of adsorption-based heating systems and chillers is complex. They have discontinuous operating cycles, varying peak energy fluxes, and their dynamic behavior is determined by complex and coupled heat and mass transfer phenomena.

Although some adsorption-based systems are already commercially available (see Figure 1), to realize their full potential on a larger scale the technology must become far more efficient, more compact, and cheaper to produce.

One of the world’s leading research organizations in this field is the Fraunhofer Institute for Solar Energy Systems (ISE) in Freiburg, Germany. With a staff of some 1,300 employees, it investigates all aspects of solar energy transformation, storage, and use. It is part of a network of more than

65 Fraunhofer research institutes in Germany that specialize in different aspects of applied science.

Eric Laurenz and Hannes Fugmann, researchers at Fraunhofer ISE, are part of a 20-person group led by Lena Schnabel that is developing higher-efficiency heat exchangers for adsorption systems. Laurenz studies how water vapor and heat flows through porous structures with the goal of optimizing system size and efficiency, while Fugmann conducts design studies involving nonisothermal fluid flows and heat conduction in solids in order to develop better heat

FIGURE 2. Left: Experimental setup used to validate COMSOL® software models of adsorption kinetics, consisting of a thin 50x50 mm2 layer of zeolite sorbent on an aluminum carrier, placed on a cold plate in a dosing chamber and monitored with temperature and heat flux sensors.

Right: Graph showing excellent agreement between simulated and measured water vapor pressure in a zeolite sorbent test setup at Fraunhofer ISE.

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thermal compressors by periodically heating and cooling an adsorbent material at different temperatures and pressures.

These systems can replace electrically driven mechanical compressors in heat pumps and chillers with the extra benefit of offering heat storage capacity, which can store up to three times the energy stored using traditional hot water systems.

FIGURE 1. Example of a commercially available adsorption-based chiller.

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ADSORPTION-BASED HEAT EXCHANGERS | SUSTAINABLE ENERGY exchanger architectures.

“Analytical methods are inadequate for our work because of the strong nonlinear couplings between the heat and mass transfer involved,” Laurenz said. “We need to use numerical tools such as COMSOL Multiphysics® to simulate the cyclic loading and unloading of the sorbent and take into account the temperature and mass distribution in both space and time. With these tools, we can make sure that the simulation will correctly capture the dynamics of adsorption and desorption.”

As a general approach, the team uses a combination of simulation and well-defined, small-scale experiments to build large-scale models that can accurately predict the complex real-world behavior of the physics being investigated. With the small-scale models, the team can fully model the physical mechanisms in detail, while on the larger scales, complexity can be reduced to save on computational time. This approach can significantly reduce the need to build full-size physical prototypes, saving both time and money.

USING ADSORPTION FOR HEATING AND COOLING SYSTEMS A schematic of the two-step cycle used to design adsorption-based chillers and heat pumps is shown in the figure below. To explain, let’s look at what takes place during the heat pump mode. The cycle is composed of one adsorption and one desorption step. During the adsorption step, the working fluid is evaporated at a low temperature. At the same time, the working fluid is adsorbed by an adsorbent at a medium temperature, where the heat released can be used to heat a building.

Once the sorbent is saturated, the process is inverted and the desorption step starts. The sorbent is heated to a high temperature, thereby desorbing the working fluid. Next, the working fluid is condensed at a medium temperature, and the released heat of condensation can be used to heat a building.

In summary, for heating applications (heat pumps) the building is heated while energy is removed from the environment. Conversely, in cooling applications (chillers), the building is cooled down while heat is released to the environment. When the cycle is interrupted, the potential heat of adsorption can be stored loss free. Depending on the desired application, adsorption can be used to heat or chill a building, while the environment acts as either a heat source or sink.

VALIDATING THE ADSORPTION PROCESS

One of the key objectives for improving adsorption heat exchangers is to optimize the uptake speed and capacity of the thin sorbent layers used in the system. In one investigation, simulation was used by Lena Schnabel and Gerrit Füldner to build a model that captured the heat and mass transfer interplay dynamics happening in the sorbent layer. With the help of the model, the group was able to fully understand the measurements obtained from the experimental setup shown at left in Figure 2.

“Only by comparing experimental and simulation results using parameter estimation were we able to determine the transport coefficients that could not be measured directly,” describes Laurenz. “This data was then used in our more complex simulations of the system.”

Schnabel’s group first started using COMSOL Multiphysics nearly ten years ago. More recently, however, the group has started to use models with varying levels of detail to estimate transport parameters and to simulate the cyclic behavior of complete systems under dynamically changing operating conditions. The ability to easily simulate coupled physics in complex and dynamic systems has proven indispensable for much of their research at Fraunhofer ISE.

ENHANCED HEAT EXCHANGER DESIGNS

In his work to optimize heat exchanger architectures, Fugmann performs basic research on heat exchanger designs, including chillers and heat pumps. Some of his geometries are designed to increase heat transfer surface area using wire structures such as those shown in Figure 3, as opposed to the more traditional fin-and-tube heat exchanger designs. In these novel architectures, a wire structure is woven or knitted around a series of tubes, separating the two fluids in the heat exchanger. In an experimental setup for a gas-to-liquid wire heat exchanger, hot water flows within the tubes while cold air flows between the tubes and across the wires.

“We found that if we use wire structures, we can achieve a higher heat transfer coefficient with a larger surface, as COMSOL NEWS

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FIGURE 3. Left: Device geometry showing warm water entering the tubes. Cold air is passed across the tubes, cooling the water as it flows through the tubes. Middle: Simulated geometry showing the cold air entry and warm air exit. The wire structure and the tubes are shown in purple. Right: Device geometry used in experimental testing.

well as significantly reduce material usage,” said Fugmann. “We are able to do this without noticeably increasing the pressure drop, and the flexibility of the wire structures also gives us the ability to easily adapt the geometry depending on the operating parameters of the design.”

Using COMSOL® software, Fugmann performed parametric sweeps to investigate specific pressure drops, heat transfer coefficients, material usage, and other analyses of the design’s geometry. Figure 4 shows the temperature distribution and the velocity magnitude of an optimized geometry of the wire structure and the tubes.

Fugmann describes the device: “From the measurements, we found that the bonded connections between wires and tubes yield a high and dominating heat resistance.

By understanding the limitations of heat transfer in the wire structures, we can further optimize the design.”

Due to their higher heat exchange surface per volume, the wire structures are also analyzed experimentally and

numerically at Fraunhofer ISE for use as sorptivecoated structures and as surface enlargement for heat exchangers in thermal storages.

LOOKING AHEAD

“Our immediate goal is to increase knowledge and competence in these areas so that we can help both our customers and others at Fraunhofer ISE who are developing different aspects of adsorptive climate control systems,” said Laurenz.

“Longer-term, we look forward to the day when such technologies are in widespread use in society, helping to reduce the load on the electrical grid and conserve the earth’s resources.”

The Fraunhofer ISE team includes (from left) Hannes Fugmann, Gerrit Füldner, Lena Schnabel, and Eric Laurenz. They are standing in front of an experimental setup for the dynamic characterization of adsorption heat exchangers. The setup is used to generate experimental data for simulation-based parameter estimation.

REFERENCES

Füldner, G. & Schnabel, L., 2008. Non-Isothermal Kinetics of Water Adsorption in Compact Adsorbent Layers on a Metal Support. In Proceedings of the COMSOL Conference 2008 Hannover. COMSOL Conference. Hannover.

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FIGURE 4. Left: Simulations showing velocity streamlines and the temperature distribution in air, in the tube wall, and in the wire connecting the two tubes (red: warm; blue: cold). Right: Simulations showing the velocity magnitude in air (red: high; blue: low).

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COMSOL BLOG

COMSOL BLOG SHARES THE LATEST IN MULTIPHYSICS SIMULATION

The engineering community turns to the COMSOL Blog for answers to multiphysics simulation questions and fun reads.

by FANNY LITTMARCK Engineers around the world are leaning on the COMSOL Blog as a go-to resource for multiphysics simulation. Readers learn about when, why, and how to best use COMSOL Multiphysics® software —directly from the experts. All blog posts are written and published in-house by application engineers and other COMSOL staff, with the occasional guest blogger. The variety of authors ensures a wide range of content, from highly technical details to lighter informative reads.

FIGURE 1. Screenshot of the COMSOL Blog.

FROM SUPPORT ANSWERS TO RELEASE NEWS AND EVERYTHING IN BETWEEN

The blog content mix spans over 40 topic categories, organized by physics for the most part to enable easy browsing of relevant content. Users of COMSOL Multiphysics refer to the COMSOL Blog for answers to common support questions, modeling tips, release news, COMSOL Conference updates, and more. In addition to information specific to the COMSOL® simulation software, the Trending Topics category contains popular science blog posts for all to enjoy.

While the majority of blog posts are published as standalone pieces, some topics are more detailed and stretch over several blog entries in a series. The most popular series is one on solvers, where Applications Engineer Walter Frei explains what happens under the hood when the COMSOL software is solving models. Other fan favorites include series on postprocessing tips, high-performance computing (HPC), the weak form, and more. A tag cloud organizes all of the series in the bottom of the right-hand sidebar on the blog and is updated as new series are launched.

FIGURE 2. Left: Ray path in a concert hall from the blog post “Modeling Room Acoustics with COMSOL Multiphysics”.

Right: Touchscreen watch from the blog post “Analyzing Capacitive Touchscreens in Consumer Electronics”.

EXPLORE THE COMSOL BLOG

With fresh content published Monday through Friday each week and covering a variety of topics, the COMSOL Blog has something for everyone. Visit the blog now for the latest in multiphysics simulation by navigating to it directly at www.comsol.com/blogs or from any page on the COMSOL website via the Community section in the footer.

FIGURE 3. Tag cloud featuring COMSOL Blog series.

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GUEST EDITORIAL

Simulation Apps Bring Us Closer to Mars

by JIM KNOX, MARSHALL SPACE FLIGHT CENTER, NASA My work with mathematical modeling and computer simulations began in earnest in 1987 when I signed on with the National Aeronautics and Space Administration, better known as NASA. At the time, I was developing computer simulations to support the design of carbon dioxide (CO2) removal systems for the International Space Station (ISS) life support system. CO2 is a human metabolic waste, produced at a rate of a kilogram per day per crewmember. CO2 must be removed from the crew cabin, as it will quickly become detrimental to crew health. The systems used to remove CO2 are typically based on sorption processes, which include complex interactions of heat transfer, mass transfer, and gas flow through porous media. At this time, there were no commercial options for solving a set of coupled mathematical models such as partial differential equations (PDEs); you either force-fit the physics into a thermal analysis package or wrote your own code, complete with discretization, meshing, and solution algorithms. Unfortunately, coding CO2 removal processes from scratch did not allow an appropriate focus on the challenging yet crucial task of understanding and capturing the underlying physics via appropriate

“The Application Builder will provide

the means to distribute the workload to many individuals.”

mathematical models. Configuration control was often simply ignored due to tight schedules, resulting in a code that would be quicker for a second party to rewrite than modify.

In the early 2000s, I decided to move CO2 removal simulations to a platform with built-in meshing, solvers, and postprocessing capabilities, and that could solve user-defined multiphysics PDEs. The program chosen to meet these needs was the COMSOL Multiphysics® software. Along with freeing the engineer to focus on the underlying physics, a degree of configuration control was automatically achieved via a consistent user interface, thus allowing COMSOL® software users to share computer models. My team has developed simulations that are already providing a valuable debugging capability for the ISS CO2 removal system, and will provide guidance in upgrades to that system.

As NASA looks to the next phase of human space travel, first to the vicinity of Mars, and then eventually to the Mars surface, the need for robust and efficient systems takes a quantum leap. Unlike on ISS, resupply is unavailable, and early return is impossible. Design of CO2 removal systems thus requires a new degree of optimization, including selection of adsorbents and sorbent processes.

One facet of my current position, guiding the maturation of spacecraft CO2 removal technologies for NASA’s Advanced

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Exploration Systems program, is keeping abreast of parallel developments in CO2 capture and storage.

While listening to a speaker at a recent conference, I was struck by his conclusion: For this complex technology, standard figures of merit cannot be used to optimize the processes involved.

Rather, computer simulations that capture the key physics of the process, including Jim Knox is the functional area coupled heat and mass manager for maturation of CO2 transfer in porous media, Removal systems within NASA’s must be applied. A large Advanced Exploration Systems number of parametric program. He received a BS in simulations are required to aerospace engineering from the converge on the optimal University of Colorado and an MS solution. Parametric testing in mechanical engineering from the University of Alabama. Research could also be employed, using the COMSOL Multiphysics® of course, but would be software to simulate adsorption prohibitively expensive and processes is part of his ongoing time consuming, severely PhD dissertation. limiting the number of options that can be explored.

Multiphysics applications have made great strides in solver robustness and speed. However, to accelerate 1D system simulations and enable multidimensional modeling of full CO2 removal systems, further improvements in robustness, execution rate, and memory usage are highly desirable future developments.

One feature that can be applied now to increase the execution rate of parametric studies is the Application Builder in COMSOL Multiphysics. After verification of a CO2 removal simulation against test results, the configuration can be locked down and a simulation app distributed to multiple users for parallel parametric studies. Examples of parametric variables include sorbent selections, fixed bed size, cycle times, and flow rates. The recent development of the Application Builder is very timely, as it will seamlessly facilitate this process.

In summary, early investigation of COMSOL as a platform for parametric studies towards maturation of spacecraft CO2 removal systems appears very promising. The Application Builder will provide the means to distribute the workload to many individuals. With this approach, informed selections from a wide range of possible options can be made towards finding the best solution for a CO2 removal system for the crew traveling to, and landing on, the Red Planet.

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Glen Lux, President and CEO of Lux Wind Power Ltd., was the Sustainable Technologies Category Winner of the 2013 Create the Future Contest.

He’s Creating the Future

For decades, wind turbine manufacturers have been building turbines with 3 blades, a nacelle, a pitch system, a yaw system and a tower. Lux believes it is time to change to a blade and cross cable system that is much lighter and therefore less expensive to build. This new system is simple with few moving parts and can cover a larger area, extracting more power at a much lower cost.

Lux Turbine Wind Farm

Glen Lux, President and CEO of Lux Wind Power Ltd.

Will you be next?

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Your future starts here: www.createthefuturecontest.com S P O N S O R E D

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“Winning first place in the 2013 Sustainable Technologies category opened the minds of many investors, institutions, and wind turbine manufacturers.

Discovering this ‘never been tried before’ technology has brought about a collaborative effort between many individuals and institutions to develop this low cost renewable energy source,” says Glen Lux, President and CEO of Lux Wind Power Ltd.

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Mechanical & Fluid Systems Diminutive Assembly for Nanosatellite deploYables (DANY) Miniature Release Mechanism New deployment mechanism offers improved reliability with minimum space and weight penalty.

Goddard Space Flight Center, Greenbelt, Maryland

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ubeSat appendices such as solar panels and antennas often need to be constrained by a release mechanism during launch. These appendices are then deployed once the desired orbit is reached. The usual constraint method used is a combination of an unpredictable/unreliable fishing line and burning wire. If a proper release mechanism is used, it utilizes a considerable amount of CubeSat internal space, making the internal packaging of the satellite more difficult. These two methods have adverse effects on CubeSat performance.

The DANY mechanism provides a secure method to constrain these deployables without using any internal space due to its minimized thickness with dimensions of 1.250×2.875×0.188 in. (≈3.18×7.30×0.48 cm). DANY is fas-

tened to the chassis and provides a secure interface for the items to be deployed. Two variations of the DANY mechanism exist with different interfaces for the deployable: threaded insert or pin puller. Both variations work the same way: two pins hold the deployable directly as a pin puller or hold a threaded block to provide a threaded interface. The two pins are preloaded with springs and held in place by a plastic piece. A printed circuit board that serves as a closeout panel contains a redundant set of wires to compromise the strength of the plastic piece by heating it. Once the strength is compromised, the springs will push the pins. The mechanism also contains a set of redundant switches to confirm proper operation of the release mechanism. Nominally, the

mechanism utilizes 3 A current at 3.3 V for a total of 9.9 W for 0 to 4 s.

Several tests were conducted to characterize the mechanism such as thermal vacuum hot and cold deployments.

The mechanism was tested to –20 °C and +55 °C. The mechanism is capable of withstanding 300 lb (≈1,334 N) of force while stowed and 3 lb (13.3 N) of force while being actuated. The mechanism can be refurbished/reset by replacing the plastic piece.

This work was done by Luis Santos Soto, Scott Hesh, and John Hudeck of NASA Wallops Flight Facility for Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanical & Fluid Systems category. GSC-16900-1

Quantitative Real-Time Flow Visualization Technique This technique enables real-time monitoring of pressure fields and flow measurement.

John H. Glenn Research Center, Cleveland, Ohio

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here is a need for experimental techniques that have low cost and rapid turnaround. It is also necessary to obtain quantitative information from such a method. Previous methods are either lacking in quantitative information such as dye or smoke injection, or require considerable set-up and cost such as PIV (particle image velocimetry). A method was developed for visualizing the pressure contours for a turbine cascade in real time to enable rapid evaluation of new concepts. A method for quantitative 3D flow visualization also was developed.

The unique capability for real-time concept development and analysis was demonstrated using a Microsoft Xbox Kinect, infrared thermography, and a water table. The water table was set up and instrumented with an Xbox Kinect sensor and a projector. The Xbox Kinect

detected the water height of the free surface in real time. A computer processed the information to obtain pressure ratios, and the projection system projected the results back onto the water surface in real time. This enabled the researcher to view in real time the pressure distribution around an airfoil or geometry of interest.

3D printer models enable modularity and hot-swapping of concepts. Heated food dye was then injected into the airfoils and allowed to seep into the flow via ports on the airfoils. An infrared camera visualized the heated dye. Images from the infrared thermography can be used to extract quantitative and qualitative information about the flow such as temperature, velocity, and density, thus introducing a new class of seedless velocimetry. This new class of quantita-

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tive flow visualization is currently being developed at Glenn using a focused Schlieren technique.

This work was done by Vikram Shyam, Sameer Kulkarni, Herbert Schilling, and Adam Wroblewski of Glenn Research Center.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanical & Fluid Systems category.

NASA Glenn Research Center seeks to transfer mission technology to benefit U.S. industry. NASA invites inquiries on licensing or collaborating on this technology for commercial applications. For more information, please contact NASA Glenn Research Center’s technology transfer program at ttp@grc.nasa.gov, or visit us on the Web at https://technology.grc.nasa.gov/. Please reference LEW-19183-1.

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Thin-Film Evaporative Cooling for Side-Pumped Lasers This technology has applications in advanced lidar systems for weather satellites; in welding, cutting, and marking; and in test and measurement.

Langley Research Center, Hampton, Virginia

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highly efficient way to cool solidstate crystal lasers was developed.

This thin-film evaporative cooling technique offers higher optical efficiencies and monochromatic quality than traditional conductive cooling techniques.

Developed for use in side-pumped 2.0micron laser systems used in light detection and ranging (lidar) instruments, the thin-film cooling design concept also has broad utility for diode-pumped solid-state laser (DPSSL) systems, especially those with high heat flux or challenging packaging requirements.

The technology was developed to improve upon current water- and ammonia-based conductive cooling systems for optically pumped solid-state laser crystals. NASA is developing 2.0-micron lidar lasers that employ solid-state laser crystal rods that are optically pumped from the sides using diode lasers positioned around the circumference of the crystal. Optically pumping the crystal creates a high heat flux within the crystal. Current conductive cooling of these pumped crystal lasers is inadequate to uniformly address the generated heat flux, which can result in poor optical performance and even thermal damage to the crystal.

Water cooling can uniformly cool the laser crystal, but provides only roomtemperature cooling, which results in poor optical output efficiencies in the laser. Ammonia-based coolants offer a much lower cooling temperature, but do not provide uniform cooling throughout the laser crystals, which results in uneven cooling within the crystal. This lack of uniform cooling results in reduced monochromatic quality of the laser light. In addition, water and ammonia cooling approaches add packaging complexity.

The technology described here overcomes the drawbacks of traditional conductive cooling approaches using a unique evaporative cooling technique.

The design includes a transparent cylindrical housing that surrounds the solidstate crystal rod, creating an annular gap along the length of the rod. A suitable, common cooling fluid is injected into the gap so that the coolant liquid wets

the rod’s surface in a thin-film layer.

This thin film is critical to ensure that the cooling fluid does not boil, but instead undergoes a controlled evaporative phase change from liquid to gas.

NASA Tech Briefs, May 2015

With sufficient space between the thinfilm cooling layer and the transparent housing, the coolant can continuously evaporate into the space without boiling, and provide highly efficient cooling

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Mechanical & Fluid Systems along the length of the rod and across its radial profile. The resulting cooling is more uniform and efficient than conductive cooling approaches, and the DPSSL packaging is simplified.

Modeling the effects of evaporative cooling indicates that the NASA technique is significantly more uniform and

enables higher optical output than traditional cooling methods.

This work was done by B.K. Stewart of Langley Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanical & Fluid Systems category. LAR-17229-1

MEMS Micro-Translation Stage with Large Linear Travel Capability Marshall Space Flight Center, Alabama

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MEMS (microelectromechanical systems) micro-translation stage (MTS) with large linear travel capability was developed that uses capacitive electrostatic forces created by stators arranged linearly on both sides of a channel, and matching rotors on a moveable shuttle for precise movement of the shuttle. The device, which is essentially a linear motor built from silicon base with microfabrication techniques, will be able to rapidly translate across large distances using only threephase power. The moveable shuttle can be as small as 100 mm and can house a variety of elements including lenses and mirrors.

The shuttle can be tailored to travel distances as small as 10 mm and as large as 300 mm, with as little as 10 mm between adjacent shuttle stops.

Manipulating the capacitive forces with three-phase power enables precise movement of the shuttle in either a stepping mode with many interim stops, or in a controlled scanning mode with adjustable speed. The device is built using standard

MEMS processing technologies, and the ultimate translation length is determined by the photolithography process and the wafer size that can be accommodated in the MEMS fabrication equipment.

The translation stage at the heart of the device is the key to its flexibility in applications such as optics, communications, sensors, and biotechnology. The translation stage can move at speeds of 25 mm/ms, providing a method for rapid modulation of a laser source. The stage can also house a variety of elements such as lenses, mirrors, absorbers, and sampling compartments that would be useful in many applications.

This work was done by Cynthia Ferguson of Marshall Space Flight Center, and Jennifer English, Gregory Nordin, and Mustafa Abushagur of the University of Alabama Huntsville. For more information, contact Ronald C. Darty, Licensing Executive in the MSFC Technology Transfer Office, at Ronald.C.Darty@nasa.gov. Refer to MFS31789-1.

Planar and Non-Planar Multi-Bifurcating Stacked Radial Diffusing Valve Cages This technology is applicable in systems and devices where high-pressure-differential valves are used.

NASA’s Jet Propulsion Laboratory, Pasadena, California

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valve cage consists of a stackable planar structure design with paths that are azimuthally cut out and connected radially. The pattern causes the flow to move azimuthally and impinge on each other when moving to the next path, thereby reducing the fluid momentum and energy that reduces the erosion capability. The maze-like structure is easy to www.techbriefs.com

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machine with standard machining techniques.

In addition, the use of non-planar disk designs was implemented, which can increase the flow length for a given delta radius, and redirect the flow from the radial direction to the axial direction in counter or co-flow directions. A variety of nonplanar disk shapes are apparent that can

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both increase the flow length, and redirect the flow from the radial direction to the axial direction or conversely. In addition, depending how the cage is oriented, the inlet flow to the main line can be directed counter to the main flow, or co-linear with the main flow.

The valve cage can be used to reduce erosion due to high-pressure jet flows, reduce cavitation by increasing the flow areas in a smooth manner, and reduce valve noise associated with pressure surge. The control features that allow for fine tuning the output pressure and flow velocity include azimuthal, radial, and axial paths in the plates; impinging flows; constricting and dilating flow surfaces; redirecting flow counter and inline with main flow; and redirecting radial to axial, or azimuthal, or viceversa. These are achieved by adjusting the width of channels, the number of channels, the angular extent of each barrier, misalignment of openings, nonplanar geometry of the stackable rings, using variable shaping of the geometry of the obstructing elements that make up the individual layers, and the direction of exit flow from the plate.

An example of a valve cage in a co-annular flow system. The valve on the left is closed, and the valve on the right is half-open.

This design specifically addresses the problems associated with shutting off a highpressure valve; namely, potential pressure surge, high-pressure jets, and potential cavitation, all of which can cause damage to the valve body or to the outflow or inflow pipes.

This work was done by Stewart Sherrit, Mircea Badescu, Xiaoqi Bao, and Yoseph BarCohen of Caltech for NASA’s Jet Propulsion Laboratory. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanical & Fluid Systems category.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to: Innovative Technology Assets Management JPL Mail Stop 321-123 4800 Oak Grove Drive Pasadena, CA 91109-8099 E-mail: iaoffice@jpl.nasa.gov Refer to NPO-48745, volume and number of this NASA Tech Briefs issue, and the page number.

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Aeronautics Real-Time Aerodynamic Parameter Estimation Without Airflow Angle Measurements Langley Research Center, Hampton, Virginia

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ccurate measurements of airflow angles are among the most expensive and difficult to obtain in flight testing because of the complexity of the airflow near the aircraft and the consequent need to carefully mount and calibrate the sensors. A novel technique was developed for determining aerodynamic stability and control parameters from flight data in real time, without airflow angle measurements (airflow angle and sideslip angle).

The technique combines kinematic reconstruction of airflow angle data and real-time parameter estimation in the frequency domain in a new way to produce accurate characterization of aircraft stability and control in real time, with no requirement for direct measurement of airflow angles. Kinematic reconstruction is used to supply the missing angle of attack and sideslip angle data using data

from other sensors, namely an inertial measurement unit (IMU), a pitot tube for static and dynamic pressure, and ambient temperature.

Reconstructed angle of attack and sideslip angle data exhibit unknown bias and drift, making the reconstructed data useless for typical modeling approaches.

However, the real-time frequency-domain modeling approach can be made insensitive to unknown bias and drift errors in the data, and therefore can be used effectively with reconstructed airflow angle data.

The approach is simple and accurate, and produces high-quality real-time modeling results for flight testing without airflow angle instrumentation. The method could be implemented in any aircraft with a flight computer and data from an IMU, along with ambient temperature and pressure, dynamic pressure, and measured

control surface deflections. Many modern commercial aircraft have this data available at sample rates of 25 Hz, meaning that stability and control monitoring could be provided to the pilot in real time with only a software change to non-flight-critical software in the flight computer, or by adding hardware that accesses flight data already available from the onboard data bus. The technique can also be used for rapid or low-budget flight testing, rotorcraft flight testing in hover, or aircraft accident investigations, because aerodynamic stability and control characterization can be done in real time without direct airflow angle measurements.

This work was done by Eugene A. Morelli of Langley Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Aeronautics category. LAR-17868-1

Method for Improving Control Systems with Normalized Adaptation by Optimal Control Modification Ames Research Center, Moffett Field, California

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new technology has been developed for improving performance and stability of control systems. This method represents a significant advancement in the state-of-the-art of adaptive control technology. The present invention is a new type of adaptive control law, called optimal control modification, which blends two control technologies together: optimal control and adaptive control.

The key features that differentiate this invention from the conventional art are: (1) the introduction of a damping mechanism that is proportional to a property known as persistent excitation to improve robustness of adaptation in the presence of persistently exciting signals, (2) the existence of linear asymptotic properties that make the method well suited for design and analysis for stability guarantee, and (3) the use of this adaptive control technology with a new modi-

fication of time-varying adaptive gain from two present methods — normalization and covariance adjustment — to further improve stability of the control systems in the presence of time delay and unmodeled dynamics. The method has gone through a series of validation processes ranging from many aircraft flight control simulations to a pilot-inloop evaluation in the high-fidelity Advanced Concept Flight Simulator at NASA Ames that culminated in a successful flight test program on a NASA F/A18A research test aircraft.

The invention provides a robust modification to the standard model-reference adaptive control based on an optimal control formulation. The modification enables fast adaptation for improving tracking performance without sacrificing stability robustness. The optimal control modification adaptive law can be tuned

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using a modification parameter to provide a trade-off between tracking performance and stability robustness.

Increasing improves robustness to time delay and/or unmodeled dynamics.

Simulation results for a wide variety of different aircraft models, as well as experimental data, demonstrate the effectiveness of the optimal control modification adaptive law, which improves the tracking performance significantly using a much larger adaptive gain than that for the standard model-reference adaptive control.

This work was done by Nhan T. Nguyen of NASA Ames Research Center. NASA invites companies to inquire about partnering opportunities and licensing this patented technology. Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARC-TechTransfer@mail.nasa.gov. Refer to ARC-16916-1.

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Airborne Coordinated Conflict Resolution and Detection (ACCoRD) Framework This is a prototype implementation of a mathematical framework for state-based conflict detection and resolution algorithms.

Langley Research Center, Hampton, Virginia

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o accommodate the predicted increase in air traffic, the next generation of air traffic management (ATM) systems relies on operational concepts where the responsibility for separation is distributed between airborne and ground systems. These distributed modes of operation are enabled by new positioning and communication technology that provides precise state information for ownship and traffic aircraft. A critical component of a distributed ATM system is the airborne conflict detection and resolution (CD&R) system. A CD&R system warns pilots about predicted traffic conflicts and advises them on resolution maneuvers.

The mathematical framework consists of a collection of mathematical theories in the formal notation of the Program Verification System (PVS). The framework assumes a 3D rectangular coordinate system, with two aircraft, one of which is identified as the ownship and the other as the intruder aircraft. State information, consisting of position and velocity vectors of the aircraft, is available to both aircraft. Aircraft trajectories are predicted to be linear projections of the current state. Resolution maneuvers are defined as new velocity vectors that the ownship implements instantaneously.

The protected zone is a volume around each aircraft of diameter D and height H. A loss of separation is defined as an overlap of the protected zone of two aircraft. A conflict is a predicted loss of separation between the aircraft within a look-ahead time T. A conflict detection algorithm is a function that has as input the state information of both aircraft and returns the time to conflict and the duration of the conflict. A conflict resolution algorithm is a function that receives as input the state information of the aircraft and returns a set of resolution maneuvers for the ownship. Four kinds of resolution maneuvers are considered: track only, ground speed only, optimal track/ground, and vertical speed only. Resolution maneuvers are independently correct if they yield conflict-free trajectories assuming that only the ownship maneuvers solve the con-

flict. Resolution maneuvers are coordinately correct if they yield conflict trajectories when both the ownship and the intruder aircraft maneuver.

The framework provides a set of criteria that guarantees correctness of independent and coordinated maneuvers, and algorithm definitions of maneuvers

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that yield trajectories that are tangential to the protected zone (or larger) and that satisfy these criteria. Although the framework provides concrete algorithms for conflict detection and resolution, it is applicable to a variety of state-based CD&R algorithms. The approach guarantees that different implementations can safely coexist in the air traffic system as long as they satisfy the correctness criteria defined in the framework. The framework has been developed in a formal verification environment. The mathematical correctness extends to the algorithmic definitions provided by the framework.

This work was done by Ricky Butler of Langley Research Center, and Cesar Munoz and Gilles Dowek of the National Institute of Aerospace.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Aeronautics category. LAR-17785-1

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he health and integrity of aircraft sensors and instruments play a critical role in aviation safety. Inaccurate or false readings due to icing of airspeed sensors in flight can lead to improper decision-making, resulting in serious consequences. Icing or blockages of pitot airspeed sensors provide very little indication of sensor malfunction. Sensor output may indicate high, low, or nonfunctioning state, and not be responsive to actual changes in airspeed.

This innovation provides an assessment of the health and reliability of pitot airspeed signals in flight, as well as a capability for testing the pitot sensor pre-flight. The output of a process sensor contains a static component representing the process parameter and a dynamic component representing the process fluctuations. Using the dynamic component, the dynamic response of the sensing system can be determined.

As the sensor is impaired or degraded, changes to the dynamic response are observed. Various algorithms, including autoregressive modeling and statistical evaluation of the pitot airspeed signal, were integrated into a pitot health monitoring system enabling identification of icing events that degraded the pitot airspeed signal output. The realtime evaluation of the dynamic content of the process sensor’s signal output is used to assess the health and reliability of the sensing channel.

As all aircraft rely on the accurate and reliable performance of pitot/static systems, improving the detection of inaccurate indications would increase safety to passengers and crew, reduce the potential for accidents, and lead to other advances in aviation technology.

This work was done by Hashem Hashemian of Analysis & Measurement Services Corp. for Glenn Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Aeronautics category.

Inquiries concerning rights for the commercial use of this invention should be addressed to NASA Glenn Research Center, Technology Transfer Office, at ttp@grc.nasa.gov. Refer to LEW19153-1.

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NASA Aircraft Management Information System (NAMIS)

Photo Etched Parts

Lyndon B. Johnson Space Center, Houston, Texas

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he NASA Aircraft Management Information System (NAMIS) is an Enterprise Resource Planning/Mission Support software suite designed to meet both the mission support requirements and the business management requirements of NASA Johnson Space Center’s (JSC) Aircraft Operations Division (AOD). The concept and 11 high-level requirements were conceived in 1996.

NAMIS was then developed over a period of 12 years in a series of modular, integrated components designed to meet those 11 requirements. The requirements were adopted by NASA’s Intercenter Aircraft Operations Panel (IAOP) in March 2003 as the basis for defining a common aircraft management solution for use at all NASA centers to replace both legacy systems and paper-based systems with one integrated software solution to track aircraft-related activities for NASA. In August 2005, the Aircraft Management Division (AMD) at NASA Headquarters, working through the Integrated Enterprise Management Program (IEMP), chose NAMIS as the solution for all NASA centers with aircraft in order to provide: A. Tools and processes that will eliminate the risk of conducting flight operations: In aircraft with overdue inspections, In aircraft with grounding discrepancies, In aircraft not properly configured for the mission, and By any aircrew not current and qualified for the mission.

• Components as thin as .0005" • Eliminates cost of hard tooling • Eliminates burring and stress • Short lead times • Prototype through production • In-house forming, laminating & plating

B. Tools and processes that will provide continuous and positive control of all assets including materials, parts, and equipment that exceed a customerdefined value.

C. Tools and processes that will reduce the material costs and labor hours to perform the objectives stated in the above items.

D. The data, information, and metrics required to support flight operations management and business decisions.

E. The data required by other systems and external components to support consistent and accurate financial reporting and asset accounting by the Centers and the Agency as set forth in the NASA property and financial management regulations and in the Federal Aviation Interactive Reporting System (FAIRS) report requirements.

NAMIS consists of eight separate but integrated modules. The tool at the time of this reporting has been supporting the needs of over 900 users.

This work was done by Dan Swint and Noreen McLeroy of Johnson Space Center; Matthias Borck, Aaron Benzel, Andrea Chalk, Lynn Chang, Mona Lam, Jeanne Mehsling, Robert Penry, Aurin Tesoro, Charles Wheeler, and Richard Herder of SAIC; Lokson Woo and Jason Milam of REDE, Inc.; and Yagnesh Patel of QTS Inc. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Aeronautics category. MSC-24723-1

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Sector 33 App Ames Research Center, Moffett Field, California

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ector 33 is a mobile app for the Apple and Android mobile platforms that provides a single-user, interactive air traffic control simulator (game) for mobile devices. The main features of the app include an interactive air traffic control simulation with numerous problems for two to five airplanes; introductory videos on air traffic control; scoring for the problems; awards for reaching levels of achievement; integrated solution hints; a short introduction to the simulator; help; and hints for simple proportional

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reasoning math needed to solve the problems perfectly.

This work was done by Gregory Condon and Rebecca Green of Lockheed Martin Space OPS, and William Preston and Jon Freitas of Dell Services Federal Government for Ames Research Center. More info on Sector 33 App can be downloaded from www.nasa.gov/ centers/ames/Sector33/iOS/index.html or www.nasa.gov/connect/appls.html. Contact the Ames Technology Partnerships Office at 1-855627-2249 or ARC-TechTransfer@mail.nasa.gov.

Refer to ARC-16853-1.

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TECH-ETCH, INC. sales@tech-etch.com Plymouth, MA • TEL 508-747-0300 Free Info at http://info.hotims.com/55589-789

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Health, Medicine & Biotechnology Retinal Light Processing Using Carbon Nanotubes This chip can be used as an electrical or optical sensor for the retina.

Ames Research Center, Moffett Field, California

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ASA has patented a new technology called the Vision Chip, an implantable device that has the potential to restore or supplement visual function in a diseased or damaged retina.

This technology could benefit millions of people in the US and globally who suffer from degenerative diseases of the eye’s retina such as age-related macular degeneration (AMD), retinitis pigmentosa (RP), and, in some cases, diabetic retinopathy. The Vision Chip is targeted to treat AMD and other degenerative diseases of the retina by replacing a compromised retinal photoreceptor system with an array of equivalent external photoreceptors and carbon nanotube (CNT) “towers” (bundles of CNTs) that provide a pathway to transmit signals from the external photoreceptors to an active layer of retina.

The Vision Chip provides an alternative, pixel-sized, wavelength-sensitive light path around diseased, injured, or deficient areas to functioning retina. The

implantable Vision Chip is based on CNTs or CNT bundles used as photodetectors, electrodes, transducers, or physical guides to transmit optoelectrical signals in response to light. Each array of CNT towers connects to a pixel at one end, and penetrates the active retina at the other end. The chip’s array of electrically conducting or semiconducting CNT towers projects orthogonally from the surface of a silicon chip or similar solid support. The separate electrical connections allow for towers to be electrically stimulated independently for high resolution and flexibility. An insulating layer covers the electrical circuitry, thereby electrically isolating the eye tissue.

A key design feature is sufficient mechanical stability of the towers to permit insertion into retinal tissue, either from the anterior or the posterior aspect of the retina, without breaking or dislodging the CNT towers. A ground electrode, or counter-electrode, is incorporated onto the Vision Chip to optimize

electrical stimulation and electrical sensing from eye tissue. Benefits can include partial or full restoration of vision for those with certain retina disorders, injuries, and diseases like AMD or RP. In addition, light sensitivities of the system can be “tuned” to respond to certain frequencies or amplified nonlinearly, so certain forms of color blindness and night blindness may benefit from this technology. The Vision Chip can also be used as an electrical sensor for the retina in fundamental vision science research to understand the eye’s processing and integration of light signals.

This work was done by David J. Loftus of Ames Research Center, and Theodore Leng and Harvey Fishman of Stanford University.

NASA invites companies to inquire about partnering opportunities and licensing this patented technology. Contact the Ames Technology Partnerships Office at 1-855-6272249 or ARC-TechTransfer@mail.nasa.gov.

Refer to ARC-14941-1.

Provision of Carbon Nanotube Buckypaper Cages for Immune Shielding of Cells, Tissues, and Medical Devices This method may prevent the rejection of transplanted cells and tissue.

Ames Research Center, Moffett Field, California

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ASA has patented a new technology that may prevent the rejection of transplanted cells and tissues. The human immune system identifies and rejects non-host cells and tissues with high efficiency. The new invention involves the fabrication and use of carbon nanotube buckypaper (CNTBP) “cages” for immune shielding. This approach promotes and supports a variety of useful biological processes that are difficult or impossible when cells or tissue are maintained in culture outside the body. It allows for the transplantation of cells or tissues from unrelated donors or from unrelated species (xenografts) into host subjects with dra-

matically reduced potential for rejection and/or the use of immunosuppressive therapies, which can be highly toxic.

Current strategies for islet cell transplantation, for example, have shown marginal success due to limited graft survival, even with immunosuppressive therapy.

The buckypaper cage concept provides construction of one or more cages, envelopes, enclosures, or receptacles (referred to collectively herein as a “cage”) made primarily of CNTBP, and is a strategy for transplanting multiple types of cells and tissue in various applications and environments. The biological material is placed in a structure — a cage — that promotes desirable charac-

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teristics like immune shielding, physical structure, porosity, and biocompatibility.

The innovation can also be used to provide a microenvironment (within the human or other host body), in which temperature, pH, oxygen levels, carbon dioxide levels, nutrient levels, metabolite levels, and levels of cytokines and other regulatory molecules (including molecules that may not be characterized) are optimum to permit differentiation of cells or the assembly of tissue structures for later use in tissue engineering applications. The immune shield cage can also be configured to perform sensing and secretion functions, where certain molecules trigger

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the release of desired substances and control the biological functioning of the material inside the cage. Chemical modification of the cage material is also possible in order to suit the particular environment or application, and to obviate the need for immunosuppressive drugs.

Specific benefits include biocompatibility, an ease of engineering to create a variety of shapes and forms, and cage material that allows the cells and tissue to be maintained in a live and functioning state. The cage material is also flexible and resilient and does not provoke

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an immune response, does not elicit scar formation, and resists protein deposition. This innovation allows for the ability to control the dimensions of the cage, and optimizes the transport of metabolic substances into and out of the cage.

This work was done by David Loftus of Ames Research Center. NASA invites companies to inquire about partnering opportunities and licensing this patented technology.

Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARCTechTransfer@mail.nasa.gov. Refer to ARC15088-1.

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Maximum resolution will be improved at least 100-fold compared to biological ion-channel measurements.

Ames Research Center, Moffett Field, California

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olid-state, nanopore-based analysis of nucleic acid polymers is the only technique that can determine information content in single molecules of genetic material at the speed of 1 subunit per microsecond. Because individual molecules are counted, the output is intrinsically quantitative. The nanopore approach is more generalized than any other method, and in principle may be used to analyze any polymer molecule, including proteins.

The approach to the development of a solid-state nanopore device is novel in the use of nanofabrication, nanoelectric components, and high-speed signal acquisition.

A novel geometry of the solid-state nanopore (less than 5 nm in length and 5 nm in diameter) will enable 1- to 5-nucleotide resolution measurements. This means that maximum resolution will be improved at least 100fold compared to biological ion-channel measurements. The solid-state nanopore sensor will be made to enable sequencing DNA at a much faster rate than presently possible without the need for extensive sample preparation procedures, such as enzymatic amplification and labeling reactions. It will analyze electronic properties of individual subunits of DNA and RNA to obtain linear composition of each genetic polymer molecule.

Experimentation resulted in a solidstate nanopore that was created using nanofabrication techniques. The

nanopore channel with a diameter and length of less than 5 nm is made in a silicon-based chip that has nanoelectrodes placed adjacent to the pore.

High-speed electronic equipment with exceptional signal acquisition capabilities is used to analyze electronic properties of individual subunits of DNA or RNA to obtain a linear composition of each genetic polymer molecule. The nanopore sensor is expected to have unmatched speed and sensitivity of DNA detection and sequencing, enabling personalized molecular medicine, revolutionary modification of agriculture and food industries, and decoding of ecosystem-wide genetic variation. The tremendous payoffs of such a nanopore sensor are twofold.

First, the complete DNA sequence information underlying the biodiversity of planet Earth will be within reach, thus enabling a complete understanding of the molecular basis of life.

Second, such a robust sensor would enable the detection of life on other planets by detecting any informationencoding biopolymers, and would also apply to real-time molecular astronaut health monitoring, and pathogen and environment monitoring systems.

This work was done at Ames Research Center. NASA invites companies to inquire about licensing this patented technology.

Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARCTechTransfer@mail.nasa.gov. Refer to ARC-15204-1.

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Health, Medicine & Biotechnology

High-Density, Homogenous Bacterial Spore Distributions on Test Surfaces

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This method uses polycarbonate membrane to transfer spores onto a mirror surface.

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NASAâ&#x20AC;&#x2122;s Jet Propulsion Laboratory, Pasadena, California

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hus far, spore transfer had been successful from the polycarbonate membrane onto stainless steel, aluminum, and to some extent, glass. In order to image the endospores under an ESEM (environmental scanning electron microscope), the spores were transferred onto a 4-mm-diameter, mirror-polished, stainless steel ESEM tab. For the spectroscopic and irradiation procedures in the Planetary Ice Group, it has also been necessary to transfer a highly concentrated, homogenous layer of spores onto a 1/2- or 1-in. ( 1.3- or 2.5-cm) aluminum mirror. Various other methods have been developed and tested for statistical spore deposition and transfer, but transfer was previously prone to uneven coverage due to poor contact, as well as visible microdroplets from over-saturation of the backing filter contact or non-homogeneity on a larger scale. A complete, reproducible method follows to avoid these issues and ensure quantitative predictions and uniformity.

Using a standard vacuum filtration setup with a 47-mm-diameter funnel and sterile materials, the desired number of spores is deposited onto the polycarbonate membrane with approximately 150 mL of sterile water and additional water to remove any remaining spores from the inside of the solution tube. It is easier to work with total spore counts in this case, rather than concentrations. The solution is mixed thoroughly with vortex and/or sonication before pouring into the filtration device. A 47-mm-diameter backing filter is wetted with deionized water to a point of saturation such that the filter is uniformly saturated, yet no additional water remains on the surface or beneath the filter. The spore-covered polycarbonate membrane is saturated directly by placing it onto the backing filter. It should adhere to the backing filter smoothly with no air bubbles, but not so that it is enveloped in excess water. Using two pairs of tweezers to ensure a firm grasp on the membrane, the saturated membrane is placed spore-side down onto the desired substrate. It should be allowed to stick evenly to the surface. For the 4-mm-diameter ESEM tabs, it is easiest if these have been previously attached with carbon tape to a larger ESEM stub. The membrane and substrate are blown with N2 gas so that it dries quickly and evenly. The membrane is removed, and the spores should remain on the mirror.

It has been determined in this method that the concentration required to form a 0.9 monolayer coverage is 1.17 Ă&#x2014; 108 spores/cm2. In addition, glass (microscope slides) is currently being investigated as a substrate that would be particularly useful for biological applications. A quantitative analysis of the spore transferring and recovering methods using culture counts is in progress to show that the density prediction based on the initial concentration of spore solution in the filtration process is accurate.

This work was done by Adrian Ponce, Arin R. Greenwood, and Aaron C. Noell of Caltech for NASAâ&#x20AC;&#x2122;s Jet Propulsion Laboratory. For more information, contact iaoffice@jpl.nasa.gov. NPO-48810

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Team Game and Simulation Control

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Langley Research Center, Hampton, Virginia

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his technology is an offshoot of LaRCdeveloped technologies using physiological measures for assessing pilot stress, sustained attention, engagement, and awareness in a laboratory flight simulation environment. The technology allows modulation of player inputs to a video game or simulation from a user interface device based on the player’s psychophysiological state. It exploits current wireless motion-sensing technologies to utilize physiological signals for input modulation. These signals include, but are not limited to, heart rate, muscle tension, and brain wave activity. The invention is a technology for training teams to maintain functional states that are conducive to effective performance of manual tasks such as flight control, by physiologically modulating operator input devices to simulations. The invention also permits individuals who are physically challenged to participate in electronic game play by collaborating with a player who is able to

manipulate controls that the challenged player cannot, and enables individuals with different skill sets and interests (physiological self-control vs. physical performance skills) to join together in rewarding game play. Besides gaming, this technology has application in athletic training and mindbody medicine.

The capability has been successfully prototyped using the Nintendo Wii™ console and wireless Wii™ remote. Prototypes have been designed to extend the capabilities to the PlayStation®Move, Xbox Kinect, and other similar game platforms.

This work was done by Alan Pope, Chad Stephens, and Nina Blanson of NASA Langley Research Center, and Olafur S. Palsson of University of North Carolina School of Medicine.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Health, Medicine & Biotechnology category. LAR17869-1/95-1/951-1

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CRP Aptamers to Bone-Specific Alkaline Phosphatase (BAP) Lyndon B. Johnson Space Center, Houston, Texas

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n order to detect and quantify bone-specific alkaline phosphatase (BAP) in a human biological sample, a binding agent (molecule) that specifically recognizes BAP in a sample is typically required. This binding agent can then be used in numerous assays/instruments to enable the detection and quantification of BAP. BAP is a unique protein expressed in human serum, and no prior art has described a DNA-based molecule that binds to BAP. BAP levels in human serum may provide information related to bone metabolism in astronauts during longduration exposure to microgravity.

Antibodies exist that bind specifically to BAP; however, they must be stored longterm in freezers. Additionally, antibodies are typically not stable to more than a few hours in ambient conditions, whereas the aptamer to BAP is ambient stable for years.

DNA-based molecules that are chemically synthesized and that bind to a specific protein (bone-specific alkaline phosphatase) in solution have been developed. A solution-based process for

aptamer selection was used to identify specific DNA sequences that have affinity for BAP. Generally, a solution of many DNA strands was synthesized; the BAP protein was immobilized on a filter and also on magnetic beads. The library solution was passed over the target, and the DNA strands that bound to the target were amplified. These steps were repeated numerous times.

Several DNA sequences were isolated that bind with high affinity and good specificity to C-reactive protein (CRP).

This binding to CRP enables quantification of CRP in a biological sample. CRP is an important protein in the human body, and measuring the quantity of CRP in a blood sample is of interest during the study and/or diagnosis of numerous diseases and conditions. The DNA-based aptamers do not require refrigeration.

This work was done by Xianbin Yang, Nancy Ward, and Ross Durland of AM Biotechnologies for Johnson Space Center. For more information, download the Technical Support Package (free white paper) under the Health, Medicine & Biotechnology category. MSC-24629-1/5440-1

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Communications VCSEL Laser Array for Communications Ames Research Center, Moffett Field, California

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ptical communications in terrestrial and space environments require transmitted signals on the order of 40 GHz and higher, because of the uncertain and changing transmission environments.

A robust communications system is needed that will provide these frequencies and substantial discrimination between different signals, which permit switching times on the order of 0.25 ps, and that permit the use of two or more distinct signals.

The vertical cavity surface emitting laser (VCSEL) array has been developed

by NASA to use external modulation of light from two or more coherently coupled VCSEL lasers to provide a very-highfrequency, fast-switching output beam for terrestrial and/or space communications.

The invention includes application of an array of VCSELs spatially coupled together. A current source is connected to the VCSELs, with a steady current biased above threshold current, where the coupling of the VCSELs produces an output laser beam having a spatial oscillation. A switching device is used that transfers the near laser field emitted by two or more coupled VCSELs to two receivers where external modulation is then used.

Another embodiment produces a far field device where two VCSELs produce an output beam that is also received and processed by an external modulation system. The resulting far field pattern has two lobes that oscillate out of phase and are useful for beam switching.

Dynamic beam switching of VCSELs has important applications for switching and routing in optical interconnect networks. This invention is based on computer simulations of the light output of an array of two or more coupled VCSELs. The model equations that are solved on the computer are an approximation to the semiconductor Maxwell-Bloch equations. The invention produces an optical data stream from an external modulator that receives an optical pulse train from an array of coherently coupled VCSELs. This work was done by Peter M. Goorjian of Ames Research Center. NASA invites companies to inquire about partnering opportunities and licensing this patented technology. Contact the Ames Technology Partnerships Office at 1-855-6272249 or ARC-TechTransfer@mail.nasa.gov.

Refer to ARC-14682-2.

Providing a Real-Time Audible Message to a Pilot This real-time weather and environmental data reporting approach is useful for commercial airlines.

Ames Research Center, Moffett Field, California

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n aircraft pilot would prefer to receive information on weather patterns, obstructions, and other conditions that may interfere with a flight plan, formal or informal, as the pilot’s flight proceeds, with a latency of no more than a few minutes. Learning of, and reacting to, a changing environment within minutes after the change is first observed and reported is not possible with pilot’s reports (PIREPs), as presently provided. Instead, receipt of a pilot’s report (PIREP) often occurs offline, before a pilot’s own flight has begun, and with an associated latency of one to six hours. The present invention, described as an audio twitter approach, removes most of the latency associated with a PIREP and allows expansion of, and selective filtering of, information that is directly useful to the recipient pilot (RP).

An audio twitter approach, with appropriate signal filtering, is used to provide real-time PIREPs that communi-

cate weather patterns and other environmental factors from aircraft that precede a given aircraft along a flight path.

The method begins with receipt of all text messages that are communicated by, or received by, aircraft within a selected distance from the inquiring pilot’s aircraft (IPA). This information is filtered by a receiver on the IPA, using a list of N target words and phrases (TWP) for which the subject is of concern to the inquiring pilot (IP). The filter can further be set to limit the TWPs chosen to TWPs (1) that are originated within a selected distance d from, and in a selected sector relative to, the IPA [e.g., within 200 miles (322 km) in a sector that extends north and west relative to the IPA present location]; and (2) that are originated within a selected time interval (e.g., within 120 minutes of the present time).

Messages containing one or more of the selected TWPs are presented in a selected order (e.g., chronological) as

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text or, alternatively, as verbal messages for review by the pilot. Upon receipt of the TWPs, the IP determines if any action should be taken by that IP in order to avoid or minimize delay associated with the TWP information.

Communication between the IP and any other pilot within the prescribed range, geographic sector, and/or time interval is implemented using a publish and subscribe approach to exchange relevant data. A pilot, such as the IP, determines which information that IP is willing to share, and with whom (publish), and from whom the IP is interested in receiving information (subscribe).

This approach will avoid the radio chatter that often accompanies a party line system. The information received may be audibly displayed using a text-tospeech conversion module that does not rely upon visual recognition and response. A message received by the IP through the filtering process need not originate from another pilot but may be

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Scaling Amplifier from any source to which the IP is subscribed [e.g. Air Traffic Control (ATC) or other information providers].

This approach facilitates receipt and response by an airborne aircraft of relevant weather and other environmental data in real time, as these data are observed and transmitted by other aircraft in a vicinity of the airborne aircraft.

The relevant PIREPs are moved from an off-line format, to be read and reacted to hours after the observations are made,

to a real-time format that makes such observations available as they are observed and reported upon.

This work was done by Walter Johnson of Ames Research Center, and Joel Lachter, Vernol Battiste, and Robert Koteskey of the SJSU Research Foundation. NASA invites companies to inquire about partnering opportunities. Contact the Ames Technology Partnerships Office at 1-855-627-2249 or ARC-TechTransfer@mail.nasa.gov. Refer to ARC-16478-1.

Pass Plan Formatter (PPF) for Earth Sciences Ground Support System Goddard Space Flight Center, Greenbelt, Maryland

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he TRMM (Tropical Rainfall Measuring Mission) and Terra ESMO (Earth Science Mission Operations) Ground Systems needed a method of passing scheduling data through the Goddard Mission Services Evolution Center (GMSEC) bus to other subsystems without modifying the Planning and Scheduling systems and their planning data output. The original output data is used by other subsystems and not just for automation with GMSEC. The Pass Plan Formatter is a utility to reformat an ASCII MPT pass plan text (TERRA) file or the MOC (Mission Operations Center) Integrated Report (TRMM) file into an xml formatted pass plan that is passed on to the TERRA or TRMM Scenario Scheduler task via GSMEC compliant product message. This will allow automation of the input and out-

put, using the NASA GMSEC API (Application Programming Interface), for lights-out or lights-dim operations.

PPF is a Perl program that uses the GMSEC API to allow xml format commands to be saved into a GMSEC compliant Product Message and published to the bus. For TRMM, it is set up to adapt the Mission Operations Planning and Scheduling System (MOPSS) schedules for automated lights-out ground system operations, and for Terra, it is set up to adapt the Mission Planning Tool (MPT) schedules for lights-dim ground system operations.

This work was done by John Kerich and James Busch of SGT, Inc. for Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Communications category. GSC16320-1

SIM983 ... $1095 (U.S. List) · Adjustable gain and offset · 3½-digit resolution · 1 MHz bandwidth · Low-noise input · ±10 V operating range

The SIM983 Scaling Amplifier provides fine adjustable gain and offset control for analog signals.

Both gain and offset are set with 3½ digits of resolution, and the signal path has more than 1 MHz of bandwidth. Its low noise, high gain, and high slew rate make the SIM983 a convenient tool for sensitive analog signal conditioning.

Integrated Tool Archives, Extracts, and Analyzes Spacecraft Housekeeping Telemetry Data (GMSEC R3.0) Goddard Space Flight Center, Greenbelt, Maryland

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he Integrated Trending and Plotting System (ITPS) is a comprehensive tool for storage, extraction, analysis, and plots of spacecraft housekeeping telemetry data (GMSEC R3.0 — Goddard Mission Services Evolution Center).

ITPS reports information to engineers, ground controllers, and scientists regarding status and health of spacecraft

and instruments. This innovation was developed to support and advance GMSEC new technology in control center development that enables the interoperability of MOC (Mission Operations Center) software components via a middleware messaging system.

ITPS was enhanced for GMSEC to provide a more flexible network interface to

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Communications support the publish, subscribe, and messaging interface of the GMSEC middleware.

This capability allows for plug-and-play and loosely coupled interfaces between the trending system and the other components or systems in the MOC environment.

The ITPS features a modular design, enabling its use in various missions;

smooth transition to operations and minimal training costs; increases efficiency by routing task automation and online data access; secure remote Web access; is fully automated for lights-out operations; and decreases risk by enabling mission management to upgrade, test, or replace components

without impacting other components or the existing system.

This work was done by Denise Reitan, Sheila Ritter, and Haim Bruner of Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Communications category. GSC-16052-1

Low-Noise Analog APDs with Impact Ionization Engineering and Negative Feedback The technology can be used in active remote sensing optical instruments.

Goddard Space Flight Center, Greenbelt, Maryland

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ilicon avalanche photodiodes (Si APDs) have low dark current and low excess noise factor, and are currently used in many of NASA’s missions. Noise equivalent power (NEP) of 40 to 50 fW/(Hz)1/2 over 140-MHz bandwidth has been demonstrated for Si APDs. Si APDs have very low responsivity for wavelengths longer than 1.1 mm, and cannot be used in future NASA lidar missions that require low noise and large-area

photodetectors operated in the shortwave infrared (SWIR) region. The need for high-performance fiber optic communications receivers has provided the impetus for substantial progress during the last two decades in the understanding and performance of InP-based APDs that exhibit high responsivity in the wavelength range from 0.9 to 1.7 mm.

The technology described here was developed for large-area, high-perfor-

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mance photodetectors sensitive in SWlR wavelengths. The technology can be used in active remote sensing optical instruments such as NASA’s ASCENDS, ACE, and Doppler Wind LIDAR, and in NASA’S free space optical communications. In addition to NASA applications, the developed technology has numerous commercial applications such as range-finding and ladar applications, optical time domain

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reflectomery (OTDR), and free-space optical communications.

The devices employ the separate absorption, charge, and multiplication (SACM) structure that has been widely used for telecommunications receivers with the addition of two critical design features: an ultra-low-noise impact ionization engineered multiplication region, and an epitaxially grown quenching barrier layer to provide negative feedback.

The basic idea of impact ionization engineering is to place thin layers with relatively low ionization threshold adjacent to layers with higher ionization threshold.

The lower noise of the impact ionization engineering structure is a result of the spatial modulation of the probability distribution for impact ionization. The heterojunction results in a more spatially localized process, which, in turn, reduces the noise. Another unique feature is an epitaxially grown quenching barrier layer.

Analog PID Controller

It is very difficult for InP-based linearmode APDs to achieve stable high gain (>50) due to the inherent positive feedback process involved in the impact ionization process and the strong dependence of ionization coefficients on electric field inside the multiplication region.

The quenching barrier layer provides negative feedback to the avalanche process by dynamically adjusting the electric field inside the multiplication region.

The dynamic negative feedback provided by the quenching barrier will further regulate the impact ionization process and make it more deterministic, which is expected to further reduce the excess noise factor.

This work was done by Mark Itzler and Xudong Jiang of Princeton Lightwave Inc. for Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Communications category. GSC-16736-1

SIM960 ... $1750 (U.S. List) · Analog signal path / digital control

Method to Improve Wireless System Communication Coverage in a Bended Tunnel Environment

· 100 kHz bandwidth · Low-noise front end · P, I, D & Offset settable to 0.5 % · Anti-windup (fast saturation recovery)

Lyndon B. Johnson Space Center, Houston, Texas

· Bumpless transfer (manual to PID)

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The SIM960 Analog PID Controller is intended for the most demanding control applications, combining analog signal paths with digital parameter setting. High-bandwidth control loops may be implemented without discrete time or quantization artifacts. Gain can be set from 0.1 to 1000, and an internal ramp generator can slew the setpoint voltage between start and stop levels.

he conventional methods of improving wireless system coverage performance are to increase the transmitter power and/or antenna gain.

The high transmit power could lead to more power consumption and RF exposure issues. The use of a high-gain antenna could lead to a larger antenna size and increased weight and volume.

An alternative approach would be to capture the available signal power more efficiently without increasing the transmitter power and/or increasing antenna size.

An important advantage of a wireless system for space applications in zero gravity is the flexibility; astronauts carrying portable computers are not tied to a particular wiring outlet. Wiring a space vehicle with a traditional local area network (LAN) can be very expensive and a large spacecraft may consist of multiple connected modules. Nonline-of-sight (NLOS) regions may exist in the bended tunnel environment.

Computer simulations were performed for 2.4-GHz WLAN signals

propagating inside a bended tunnel environment that exists in spacecraft with multiple connected modules. The computer-simulated results indicated that the RF signals could be weak in the NLOS shadow regions due to much weaker diffracted fields and lack of the direct signals. A method to increase the received signal levels is proposed by appropriate transmitter and receiver antenna polarization alignment.

The simulations indicate that the proposed method could significantly improve the signal strength up to an order of magnitude in a bended tunnel environment.

This work was done by James Keiser and Catherine Sham of Johnson Space Center, Shian-uei Hwu of Barrios Technology, and Buveneka Desilva of Aerodyne Industries.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Communications category. MSC25671-1

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Information Technology & Software Space Weather Database of Notifications, Knowledge, Information — DONKI Goddard Space Flight Center, Greenbelt, Maryland

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W DONKI is a comprehensive Web application for space weather forecasters, scientists, and the general space weather community. It serves as an archive for space weather activities including solar flares, coronal mass ejections (CMEs), solar energetic particles, and geomagnetic storms. An innovative feature of the system is the ability to generate, modify, and store complex linkages between space weather events — creating a comprehensive network of relationships between activities, and identifying potential cause-and-effect paradigms for each space weather event.

SW DONKI also provides public access to all human-generated event analysis and notifications produced by the Space Weather Research Center (SWRC) forecasting team at CCMC (Community Coordinated Modeling Center).

Prior to SW DONKI, there was no centralized database in existence that allowed SWRC forecasters at CCMC to capture their observed space weather events and notifications. Such information was inefficiently being captured in a blog instead. Consequently, the blog was not easily searchable, and was not a sufficient environment to facilitate discussions or collaborations within the scientific community. With the advent of SW DONKI, SWRC forecasters can now build a catalog of past, present, ongoing, and expected space weather events.

With extensive database search functionality, SW DONKI now serves as a valuable resource for spacecraft anomaly resolution activities at NASA, and general space weather research throughout the space weather community.

The design of SW DONKI consists of the database back-end and Web application front-end. The database was designed with modularity in mind. The Web application front-end follows a model-view-controller (MVC) framework architecture. The MVC framework follows the MVC architectural design pattern that separates the data model and business logics from the user interface. Using such a framework naturally encourages modularized code to be written, and promotes code reuse.

This work was done by Chiu Wiegand, Richard Mullinix, and Marlo Maddox of Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. GSC-16878-1

Core Flight System (cFS) Software Bus Network Application Version 1.0 Goddard Space Flight Center, Greenbelt, Maryland

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he Software Bus Network (SBN) is a plug-in component developed for the Core Flight System (cFS) framework that extends the core Flight Executive (cFE) Software Bus (SB) publish/subscribe messaging service across partitions, processes, processors, and networks. This extension is done transparently for cFS software components, such that cFS software components remain unchanged and are unaware of source or destination(s) location.

Borrowing concepts developed for the Internet, SBN implements a peer-to-peer networking pattern without a bus master, making it inherently fault tolerant and robust against network and system failures.

Using a multi-round heartbeat exchange, SBN rapidly detects network failures and reestablishes connections when a redundant node is

brought on line. The software has three primary functions: (1) establish and maintain a connection over the available process/processor interfaces to each peer, (2) distribute and maintain a database of subscription messages for each of the peers, and (3) distribute messages to peers that subscribed to that message identifier. Based on NASA requirements for software reliability and performance, SBN implements those three functions in a relatively simple and robust fault-tolerant design using less than 12 KB of code space.

SBN has network adapters for ARINC 653 partitions, serial inter faces, UDP/IP, and SpaceWire, with the ARINC 653 implementation having been recently certified for NASA safety critical Class A use by Johnson Space Center.

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This technology is soon to be NASA open source and is intended for use on any government and/or commercial flight software mission/project utilizing the open source, cFS framework. And as spacecraft systems move towards multiprocessor, partitioned, and distributed systems, SBN becomes a key enabling software technology in support of those next-generation platforms.

This work was originally done by Jonathan Wilmot of Goddard Space Flight Center and Robert McGraw of Space Systems Integration, LLC, with additional network adapters and extensions by Elizabeth Timmons and Jaclyn Beck of Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. GSC-16917-1

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Bessel/Butterworth Filter

STARS Finite Element Multidisciplinary Analysis Computer Program Armstrong Flight Research Center, Edwards, California

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n efficient, cost-effective, and unique computer program has been developed that analyzes a variety of practical engineering problems. STructural Analysis Routines (STARS) is a fully integrated, multidisciplinary, finite elementbased, graphic-oriented analysis tool that combines individual modules to solve complex engineering problems.

The range of applications includes structural analysis, heat transfer, linear aerodynamics, and computational fluid dynamics (CFD), as well as coupled linear and CFD-based aeroelastic, aeroacoustics, aerothermoelastic-acoustics, and aeroservoelastic analysis. Because of the tool’s highly integrated nature, it has

broad application across many engineering disciplines.

STARS integrates general-purpose analysis modules for a range of multidisciplinary applications, utilizes standard FORTRAN language to run on a variety of computational platforms, and processes large amounts of data for a finite element-based, graphic-oriented, linear and nonlinear analysis.

This work was done by Kajal Gupta of Armstrong Flight Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. DRC-011-003

SIM965 ... $1195 (U.S. List) · Bessel and Butterworth filters · 1 Hz to 500 kHz · 3-digit cutoff freq. resolution · High-pass or low-pass operation

Hazards Analysis Management Tool

· Selectable 2-, 4-, 6-, or 8-pole filter

Goddard Space Flight Center, Greenbelt, Maryland

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he Hazard Analysis Management Tool (HAMT) is comprised of a database and user interface that manages hazard analysis information, manages hazard verifications, and manages relationships between hazard attributes and project elements. The tool offers numerous benefits including the ability for multiple users to simultaneously update information, auto-generation of hazard reports, improved data consistency, ability to quickly obtain up-to-date status reports, and the ability to execute complex queries on the hazard information. This tool does not provide a mechanism for the identification of hazards. The tool requires minimal IT overhead and is easily tailored for specific projects and/or user groups. This tool was developed as a support capability, and testing was limited to the operational environment in which it was initially deployed.

Hazard analysis includes several activities that are traditionally very manually intensive (creating hazard NASA Tech Briefs, May 2015

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The SIM965 Analog Filter is ideal for signal conditioning. Bessel filters offer linear phase and clean step response, while Butterworth filters provide excellent pass-band flatness. A choice of high-pass or low-pass filtering is selected from the front panel. Cutoff frequency is set with 3-digit resolution, and a choice of 12, 24, 36 or 48 dB/oct. rolloff is provided for either filter type.

reports, tracing project artifacts to hazards, tracking hazard verification status, etc.). The objective of the HAMT is to provide a tool that improves hazard analysis efficiency and effectiveness subsequent to the identification of the hazards.

The HAMT is small and flexible to allow end customers to tailor it for their needs. It was created to increase efficiency and effectiveness of hazard analyses. The HAMT is comprised of a Microsoft Access front end (that contains the user interface) paired with a Microsoft Access back end (that stores the hazard analysis data). The tool may be used to enter, edit, and report information throughout the analysis lifecycle.

This work was done by Chad Schaeffer and John Schmidt of TASC, Inc. for Goddard Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. GSC-16846-1

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Developing Web and Mobile Applications Integrated with Systems Utilizing the Object Management Group’s Data Distribution Service DDS-enabled applications range from human-computer interaction to data recording and retrieval.

John F. Kennedy Space Center, Florida

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everal software application development tools exist that enable the rapid development of Web applications.

Among other things, Web applications greatly enhance the human-computer interaction (HCI) required by many systems, while simplifying the problem of deploying applications to customers. Capitalizing on the new features provided by these tools could prove to be a boon to mission and project teams.

The Object Management Groups (OMG) Data Distribution Service (DDS) specification offers a standardsbased approach for building loosely coupled, complex software systems. The DDS specification includes the definition of an implementation-independent, machine-ingestible format for describing the data exchanged between software components. Such a feature contrasts with current approaches for data exchange that rely either on tightly coupled software components, or overly verbose selfdescribing data exchanges. In addition, DDS frees software engineers from having to compensate for nuanced differ-

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ences that may arise in the integration of software components.

Software engineers charged with the design and implementation of HCI features in a software solution (either supporting a specific mission or general purpose project) recognize the great potential of the new crop of Web application development tools. These engineers also recognize the value of the OMG DDS for integrating components in a complex software system. Unfortunately, integrating these two feature-rich products is currently only possible with custom solutions that require tight coupling between a software solution and a vendor’s product.

The focus of this work was the proper integration of the OMG DDS features with the new crop of Web application development tools. This effort aims to produce an architectural pattern that may be applied to implement such an integrated solution. This effort also aimed to provide a fully functional reference implementation of the architectural pattern.

The architectural pattern is built on the Node.js Web application framework (http://www.nodejs.org/). Node.js lets developers implement Web applications using the JavaScript programming language (http://www.w3schools.com/js/default.asp) and a rich collection of complementary products (https://www.npmjs.org/). Node.js also gives developers the ability to define native extensions to its JavaScript library using the C++ programming language.

The overall solution strategy centered around creating a Node.js extension that, when included, gave Node.js applications the ability to act as another software component in a DDS-enabled software system. Nuanced differences between the Node.js application and the rest of the software system would be taken care of by the DDS product.

The Node.js framework would then give developers the ability to build rich Web applications using data acquired from the DDS software system. Node.js minimizes the amount of work software developers need to invest in order to produce a custom Web application.

The Node.js extension mechanism used in this solution is extremely flexible. This flexibility, however, comes at the cost of increased work on the part of extension developers in order to achieve their goals. Thus, this solution also aimed at reducing the labor required from application developers to produce a fully capable Web application. The solution includes a set of development tools that achieves this goal while maintaining a high level of flexibility for application developers.

This work was done by Rolando Nieves of Kennedy Space Center.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. KSC-13925

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Synthetic Imaging Maneuver Optimization â&#x20AC;&#x201D; SIMO Goddard Space Flight Center, Greenbelt, Maryland

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pace-based interferometry missions have the potential to revolutionize imaging and astrometry, providing observations of unprecedented accuracy. Realizing the full potential of these interferometers poses several significant technological challenges.

These include the efficient maneuvering of multiple collectors to various baselines to make the requisite observations; regulating the path-length of science light from the collecting telescopes to the combining instrument with nanometer accuracy, despite the presence of vibration induced by internal and external disturbance sources; and demonstrating through hardware-in-theloop simulation that the numerous spacecraft (SC) subsystems can be coordinated to perform such challenging observations in a precise, efficient, and robust manner.

The SIMO program develops a methodology, calibrated through hardware-in-the-loop testing, to optimize SC maneuvers to more efficiently synthesize images for missions such as Stellar Imager (SI). Time and fuel-optimal maneuvers are only a part of the optimization

problem. Selecting the maneuver waypoints (number and location) determines the quality of the synthesized image. The number of SC, the size of the subapertures, and the type of propulsion system used also impact imaging rate, propellant mass, and mission cost.

Capturing all of these mission aspects in an integrated mission optimization framework helps mission designers to select the most appropriate architecture for meeting the needs and constraints of missions such as SI. SIMO addresses three specific challenges associated with space-based synthetic imaging: (1) optimal formation flight maneuver synthesis, (2) staged formation flight and optical control, and (3) hardware-in-theloop validation.

SIMO will develop a methodology to synthesize large, effective telescope apertures through multiple, collaborative, smaller telescopes in a precision formation, and calibrate that methodology through hardwarein-the-loop testing of the key staged formation control steps: array capture, optical capture, staged optical alignment maintenance,

reconfiguration, etc. In doing so, SIMO will demonstrate autonomous precision alignment and synchronized maneuvers, reconfigurations, and collision avoidance. The SPHERES testbed already has a limited onboard capability for optimal path planning and time optimal maneuver design and execution. By demonstrating coordinated, staged formation flight and optical control of two (and possibly three) SPHERES, SIMO will further the development of combined cm-to-nanometer-level precision formation flying control of numerous SC and their optics to enable large-baseline, sparse-aperture LTV7 optical and X-ray telescopes and interferometers. SIMO will conduct stagedcontrol experiments that combine coarse formation control with fine-level wavefront sensing-based control.

This work was done by John Merk of Aurora Flight Sciences for Goddard Space Flight Center.

For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Information Technology & Software category. GSC-16251-1

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Photonics Solutions for the Design Engineer May 2015

Fiber Optic Connectors — Single Step Polishing After Laser Cleaving Intelligent Photonic Multi-Sensor Solutions

The C12666MA UV-VIS micro-spectrometer is designed and built using MEMS (microelectrical-mechanical systems) technology, which allows it to be a fraction of the size of conventional spectrometers. The complete instrument measures 20.1 x 12.5 x 10.1 mm and weighs just 5 grams. To learn more, see the new products section on page 71.

(Photo courtesy of Hamamatsu Corporation)

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Fiber Optic Connectors Single Step Polishing After Laser Cleaving

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ith the standardization of 4G wireless, the increase in cloud storage and computing, and the push for faster network data rates, the highest quality passive interconnect systems must be used. While the robustness and size of these interconnections, fiber types, and cable management all play major roles in the backbone, what happens at the tip of the connector also greatly affects the optical performance of the system.

To start, high-quality connectors with tight tolerance ferrule holes, both in size and concentricity, must be used.

Connector termination involves several processing steps. Each of these steps has its own processing concerns.

With cable preparation, it’s important that the fiber is not damaged during stripping. Fiber chips will cause optical loss. While the connector is installed, the proper amount of epoxy and the correct cure schedule is critical. Too much epoxy and the spring will lock up; too little and voids will form. If the correct temperature isn’t met for the proper amount of time, the epoxy will not fully cure. In both cases, the longevity of the connector will be marginalized.

After cable preparation, connector installation and crimping, and epoxy curing, the end face needs to be processed.

The steps include cleaving (also called scribe and break) and polishing.

Cleaving and polishing bring the connector to the required specifications. A flaw in any of these steps may cause a yield problem. These steps also have an impact on the steps that follow, and may contribute to problems further down the termination process.

Standard polishing for single fiber connectors typically consists of three to five polishing steps, starting with relatively rough epoxy removal grit and gradually going to a final lapping film, which can be .02 um. Some of the middle steps use relatively costly diamond films, which are used multiple times to minimize the CoC (“Cost of Consumables”) per connector.

The Challenge The industry is continually looking for ways to increase yield, decrease CoC and labor expense. Reducing the number of polishing steps helps. CoC goes down, yield goes up, labor cost goes down, and less equipment and equipment mainte-

Side view of a ferrule end-face and fiber stinger after laser cleaving.

Technician cleaving fiber on a laser cleaver prior to polishing

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nance are required. There is a clear way to get there.

Traditionally, cleaving is done using a scribe tool with a sapphire, ruby or carbide tip. A careful operator has to scribe the fiber just above the cured epoxy and gently pull the tip of the fiber parallel to the fiber axis without producing a crack.

When not done properly, this resulting crack often makes the termination. This operator has to be one of the more careful and conscientious people in the factory, and does the same repetitive job all shift. If a crack does result from the scribing procedure, the connector needs to be cut off and the entire process needs to be redone. On breakout cables with many fibers, this creates other problems.

If breakouts are at precise lengths, all ends would need to be redone.

After the cleave, a manual denubbing process takes place to take the fiber stub down to the epoxy, so it doesn’t crack during the epoxy removal step. This is time consuming and very operator dependent. The connector end face can also be deformed if it isn’t done properly and it won’t be detected until testing.

With the manual cleave, traditional machine polishing requires four to five steps using silicon carbide, diamond and silicon dioxide lapping films with rubber pads after the denubbing – epoxy removal, multiple geometry end face forming, and the final – to reform the geometry of the connector.

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The Solution A new cleaving technique, using a CO2 laser, largely automates the process.

The operator simply places the connector into the laser cleaver, the laser scans across the fiber and epoxy bead, and it cleaves both together. The human factor is eliminated from the cleaving and denubbing steps.

Laser cleaving was introduced a few years ago, but a recent development produces even more savings in the termination process. Earlier laser cleaving models cleaved 70 um from the ferrule pedestal; the newer design can cleave as close as 35 um from the pedestal. The consequence

of this improvement cuts the required polishing steps from three or four to only one step, using the final polish film.

Because assembly manufacturers typically use pre-radiused 2.5 mm ferrules, and the new SSP laser cleaving leaves a very short fiber stinger, about 35 um, with an epoxy layer as thin as 10 um, polishing can be completed with only final film. Even 1.25 mm ferrules, which are not typically preradiused, can be polished with only the final film since the polished diameter is relatively small. Developments are also

being done with 1.6 mm and 2.00 mm military and commercial pins and sockets.

This process results in a connector with tightly controlled geometry, a very high yield, lower CoC, and shorter labor time.

Pencil tip 1.25 mm ferrules and 2.5 mm ferrules with relatively small pedestals, can also get polished with only one polishing step after the laser cleaving. Final lapping film has the capability to remove the residual epoxy layer, provide the specified Radius of Curvature (ROC), and control the fiber height (protrusion or undercut)

Ferrule end-face after laser cleaving – face view X5

Ferrule end-face after laser cleaving – face view X50

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Opto-semiconductors & photomultiplier tubes

Before connectors are terminated, when they are purchased, they come in with the correct geometry, radius of curvature, and apex offset. With traditional manual cleaving, the connector end face is being destroyed during the epoxy removal step and has to be reformed.

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Fiber Optic Connectors

within the desired specification to meet customer demands.

By decreasing the number of polishing steps, the cost per connector will go down. By relying on the connectors’ incoming ROC and removing all cracks due to cleaves, yields Ferrule end-face after laser cleaving – face should also improve. view X100 Note: In a production environment, there may be a requirement to perform a very brief silicon carbide polishing step to remove the epoxy residue before the final film. This also helps extend the life of the final film.

Next Steps Most 2.5 mm ferrules used by assembly manufacturers are preprocessed with an ROC of 15 to 25 mm. This ROC reduces the polishing time after traditional hand cleaving. This ROC range is too wide for many terminated connectors. The ROC distribution of incoming ferrules is too wide for the needed finished termination. With 1.25 mm ferrules, the situation is slightly different. Many assembly manufacturers use incoming ferrules with flat pedestals, as opposed to pre-radiused. To take full advantage of laser cleaving and minimize polishing as much as possible, it may help to specify incoming ferrules within the mid-range of the final connector spec, and with tighter tolerance.

A successful relationship between two companies, Fiber Optic Center (FOC) and Sagitta Engineering Solutions Ltd., has defined a business process of specialization and expertise.

Sagitta’s expertise is in laser manufacturing and automation.

FOC, on the other hand, specializes in working with cable assembly houses by consulting on and providing all the equipment and supplies needed for making up cable assemblies.

They do not, however, sell cable assemblies. FOC and Sagitta work hand-in-hand with each assembly house to figure out what, if any, changes are needed on incoming parts, as well as the implementation of the technology.

FOC’s technical experts travel to manufacturing sites, set up the laser system, and develop the most cost effective process while achieving optimum technical results. They look at the entire process, from cable preparation to testing, to make sure all stations are operating at the highest level. Once they have the process, the technical expert helps to integrate the system into the line and stays with the operators until they are completely comfortable using it. In the highly competitive world of fiber optic cable assembly, it is important to stay ahead with the best equipment and processes, and new techniques in laser cleaving can help achieve this.

This article was written by Daniel (Didi) Hachnochi, CEO, Sagitta Engineering Solutions Ltd. (Simpsonville, SC) and Ben Waite, Executive Vice President, Fiber Optic Center (New Bedford, MA). For more information, contact Mr. Hachnochi at didi.hachnochi@sagitta. com, Mr. Waite at bwaite@focenter.com or visit http:// info.hotims.com/55589-200.

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Applications Intelligent Photonic Multi-Sensor Solutions

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ith the Internet of Things (IoT) quickly rising in front of us, it would be easy to get caught in the trap of thinking that both the trajectory and applications will be somewhat predictable. While hindsight is 20/20, the future can be a little trickier to envision.

We can likely all agree that when we saw the first brick-sized wireless telephone, it wasn’t hard to tap our creative problem solving to conclude that subsequent generations were going to get smaller, cheaper and generally “better”. But few people could have envisioned the “smartphone,” let alone Apple’s first edition iPhone.

Fewer still looked from that first brick to an age of sensor-driven, cloud-connected apps in the palms of our hands.

Small Data Drives Big Data The IoT will be built upon some basic functional blocks. High level connectedness (i.e. “the internet”) is obvious, as are “the things” (smartphones, toasters, TVs, lights, thermostats). The cloud and big data are also fairly well recognized.

But where does the data come from?

One obvious answer is from our activities and behavior, led by the mobile devices we are carrying with us. Traffic reporting apps, such as Google or Waze, make use of our data every day. Our “likes” on everything from a local eatery to geo-political opinion, especially when cross-referenced with our location record, creates a vast behavioral database that everyone from friends to retail

Figure 1. Lighting and the IoT eco-system

Figure 2. New chip-level solutions bring the Internet of Awareness to our built spaces.

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coupon pushers can capitalize on. The last and somewhat unsung heroes of the IoT revolution will be the sensors.

Beyond GPS, the missing link in the big data pie is a broad, but granular, understanding of what’s going on in the spaces we occupy. Sensors will bring awareness to the Internet of Things, and lighting is a natural host for the awareness.

Phase I: A Platform is Born Our built environments have some very common ingredients, including walls, windows, furnishings, HVAC systems and lighting. Due to the combination of its “hardwired” electrical nature, and its ubiquity across our microspaces, lighting is well suited to be a primary system through which we can host many of the sensor systems that will create this “Internet of Awareness” for the IoT (Figure 1).

While the concept of connected lighting doesn’t sound particularly innovative, the reality is that very few of today’s lighting installations can really be called “connected”. A modern building management system (BMS) may be able to command banks of lights on or off on a preset schedule, track the overall trend of occupancy sensor triggers in a series of spaces, and maybe even infer the amount of energy usage/savings that those events trigger, but things pretty much stop there. In reality, prior to the start of the solid state (or LED) lighting revolution, there really wasn’t much to control beyond on and off.

Recent photonically-integrated chip level solutions (Figure 2) are enhancing both the capabilities and connectedness of our lighting, providing a preview of the coming tsunami of sensor driven awareness that will not only deliver information on lighting levels and energy usage, but a raft of building-level data that will encompass everything from air quality and space utilization to the wearable-transmitted vital signs of users in those spaces.

The whole point of the Internet of Awareness is sensing, so any system architecture decisions will naturally start by answering the question of what we intend to sense. The architecture example we use assumes the objective to be a smart lighting system, with the core functions including integrated occu-

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Figure 3. Sensor hub extensibility

pancy and ambient light sensing controlled by a smart lighting manager.

Lighting needs control, it needs sensors, and it provides the basic payback model for other sensing to ride on. For a commercial space, a system integrator expands the sensing to include such things as temperature, humidity, CO/CO2, motion and presence. Some of these sensor additions, such as direction of travel information available from a pixelated presence sensor, will provide information useful to the lighting system, while others, such as CO/CO2

sensing, are pass-through information that will be delivered back to the response to BMS. To facilitate sensor extensibility when architecting an IoT sensor hub (Figure 3), industry standard platforms should be considered. In the example above, I2C has been chosen for core expansion.

Simple UART-based connectivity, such as RS-485, can also be employed. The need for distributed intelligence must also be considered, and will be driven by the frequency and volume of the sensor data being captured. Whether you look at it as ‘sensors, with intelligence thrown in at no extra charge’, or vice versa, the simplest approach for widely distributed sensing will be a single dedicated controller which includes one or more integrated sensors. With the addition of basic wired or wireless connectivity, an IoT star is born!

The convenience of lighting as the initial sensor platform is undeniable. An existing system lighting is in place now, it’s in a convenient physical location to both provide it with power and to enable useful granularity in the data that comes from the sensed environment, and there is a convenient benefit in the form of integrated sensing and control to pro-

vide a payback in the form of basic energy savings.

Phase II: Extend the Platform to New Applications While the approach above describes one completely new concept, namely IoT-connected smart lighting serving as the extensible sensor hub of our built spaces, there is an alternate branch of the family tree that may be less obvious – the creation of a cross-application intelligent photonics platform. The basic intelligent flow found in the smart lighting manager – sense, interpret, control, communicate – coupled with sensor expansion and analog/digital inputs and outputs, can enable a wide variety of photonic-based applications.

There is an incredible amount of information in the light, and a wide array of bandwidths to choose from. The smart lighting manager used in the initial illustration is equipped with nanophotonic tri-stimulus XYZ interference filters that respond to the visible spectrum as the human eye does (Figure 4).

However, in order to normalize the filter responses across temperature and a variety of light sources (including IR influences in daylight or incandescent

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Applications sources), a total of six filters are employed to provide data on X, Y, Z, IR, dark and clear channels. While the initial application addresses the IoT smart lighting opportunity, the architecture is effectively an intelligent 6-channel spectrometer platform. The use of nano-photonic interference filters, which are laid onto the intelligent sensor platform in a standard CMOS process, enables relatively rapid filter design and implementation across a wide spectrum spanning from deep and near UV through visible to near IR (600 to 1000nm – Figure 5). In addition, the control-oriented architecture of the platform enables the onboard intelligence to be tapped for quick configuration to specific applications, while additionally delivering both decision making as well as photonic source control to support active sensing architectures (Figure 6).

Some applications in visible and nearIR include food quality assessment, chemical product safety (detecting urea or melamine in milk, for example), authentication, signal detection and medical/SpO2. Mid-IR applications include bio-sensing such as glucose monitoring, fat/cholesterol detection, and alcohol. Longwave IR (PIR) integration would require some distinct material design, but would allow sensing to extend into fire/safety as well as presence detection and people counting.

In all cases, the ability to sense, interpret and communicate the result becomes critically import to address the wide range of potential applications that exist farther over the horizon. Support for additional sensors, as provided in the examples here by the I2C bus, even creates the opportunity for hybrid systems that might bring together photonics and such diverse elements as MEMS, RFID, temperature/humidity and/or time of flight sensor systems.

In speaking to one of the original committee members of the TCP/IP protocol, they pointed out that while they never conceived that cameras would be connected to the network, they did envision that there would be things they couldn’t envision. A photonics platform approach must similarly account for that which cannot yet be accounted for. We might not know what the app is, but we do know we need to support it.

This article was written by Tom Griffiths, Marketing Manager – Sensor Driven Lighting, ams AG (Raleigh, NC). For more information, contact Mr. Griffiths at cognitivelighting@ams.com or visit http://info.hotims.com/55589-201.

Figure 4. The CIE XYZ tri-stimulus response model of the human eye

Figure 5. An example 6-channel spectrum

Figure 6. A basic multispectral architecture

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New Products Product of the Month UV-VIS Micro-Spectrometer Hamamatsu Corporation (Bridgewater, NJ) has announced the release of the C12666MA microspectrometer, a UV-VIS spectrometer about the size of a fingertip. Its miniature components, fabricated using MEMS (micro-electro-mechanical systems) technology, allow it to be a fraction of the size of traditional spectrometers. In addition, its hermetically sealed package makes it usable in high-humidity environments that traditional spectrometers do not tolerate well.

The C12666MA micro-spectrometer consists of a nanoimprinted grating and a sensor chip with an air gap between them. The sensor chip features a CMOS image sensor sensitive to 340-780 nm wavelengths and an entrance slit etched into the silicon. Etching the slit in silicon instead of using a traditional metal slit reduced the size of the C12666MA. The sensor and grating chips are sealed within a small hermetic package measuring 20.1 x 12.5 x 10.1 mm and weighing 5 grams.

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310 nm, sub 800 ps Picosecond Pulsed LED Edinburgh Instruments (Livingston, UK) has released a 310 nm picosecond pulsed LED with a sub-800 picosecond typical pulse width. This LED is optimized for Time Correlated Single Photon Counting (TCSPC). The EPLED 310 is a compact, robust, maintenance free, fully integrated system supplied in a single package. It is pre-adjusted for an optimum pulse width of <800 ps with particular attention paid to reducing a long tail in the temporal profile.

EPLED diode lasers provide a cost-effective and reliable alternative to nanosecond flashlamps and expensive mode locked Titanium Sapphire femtosecond lasers. Typical instrumentation in which the EPLED 310 may be used are fluorescence lifetime spectrometers and fluorescence lifetime multi-well plate readers for spectroscopy applications in biochemistry, biology, photophysics, semiconductor physics, bio-chemical assays etc. Customized versions of the pulsed LED can also be supplied for integration within various types of analytical instrumentation.

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UV-Visible-NIR Polarization Spectroscopy CRAIC Technologies (San Dimas, CA) recently announced the addition of UV-visible-NIR polarization spectroscopy capabilities to CRAIC microspectrophotometers. This feature is offered as a package that allows the user to measure polarization spectra in either transmission or reflectance modes. With the ability to measure polarization microspectraâ&#x201E;˘ in the ultraviolet, visible and near infrared regions, the UV-visible-NIR polarization package represents a powerful new tool for both materials science and biological research.

CRAIC Technologyâ&#x20AC;&#x2122;s polarization package consists of optics and hardware designed to be added to CRAIC Technologies microspectrophotometers. As such, it can be used to measure the polarization spectra in both transmission and incident illumination modes. Uniquely, the optics are designed to operate in the spectral range from the ultraviolet through to the near infrared regions.

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New Products Circular Variable ND Filters

Illumination Design, Analysis, & Optimization Software

Reynard Corporation (San Clemente, CA) recently announced the complete customization of their Circular Variable Neutral Density (CVND) Filters. This technology is best used in high quality optical systems to change the intensity of light from 100% to less than 0.1%. As the filter rotates, the beam intensity is customized due to the density variation of a gradient metallic coating around the filter. Used from the UV to the far infrared, density neutrality can be achieved for narrow band applications, such as lasers, to wide band applications, such as the spectrum of white light.

These filters are fully customizable in optical density gradient function, transmission gradient function, substrate type, coating materials, and size to meet customer requirements.

Gradient function can be supplied from 45° to 360° of rotation.

Substrates can be supplied from 1.0" (~25mm) to 8" (~200mm) in diameter. Densities can be supplied as a standard linear or a customized gradient function.

For Free Info Visit http://info.hotims.com/55589-216

Camera Sensor Module

www.lambdares.com +1 978-486-0766 WEPIW$PEQFHEVIW GSQ

Free Info at http://info.hotims.com/55589-806

The VRmTS-20 from VRmagic (Mannheim, Germany) is an external sensor module for the D3 intelligent camera platform. With its compact dimensions of 26 x 26 mm and the flexible cable connection to the camera base unit, the module is particularly suitable for applications with limited or angled space. The sensor module is available as OEM version and as COB S-mount M12 version with different lenses and filter glasses.

The sensor module is equipped with the CMOS sensor AR0134 from Aptina. The 1/3" sensor can capture 40 frames per second at a resolution of 1280 x 960 pixels. Up to six VRmTS-20 sensor modules can be connected to a multi-sensor camera base unit via flex-foil-cables. The modules can be positioned freely and deliver pixel-synchronous images from different perspectives. Remote-sensor cameras can be equipped with flex-foil-cables or alternatively with round cables.

For Free Info Visit http://info.hotims.com/55589-209

Laser Radiation Detector Screens The path of invisible laser radiation can be verified using detector cards from Laser Components (Hudson, NH). These cards are ready for immediate application and do not have to be activated or optically charged. The cards for wavelengths from 1.5m to 5m and 5m to 20m can localize the beam path of Hol:YAG, Er:YAG, and CO2 lasers, for example.

Laser Components has two versions available for both wavelength ranges.

The high-power versions have an active area of 40 mm x 52 mm and can be used with a laser power of up to 120 W/cm² and 50 W/cm². The highpower/low-power version has two active areas integrated into the converter card, each of which measures 40 mm x 25 mm in size. The lowpower side works up to 8 W/cm², and the power of the high-power side is identical to that of the high-power version.

For Free Info Visit http://info.hotims.com/55589-210

Photonics Tech Briefs, May 2015

Free Info at http://info.hotims.com/55589-807

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Deep UV Luminescence Spectrophotometer

MAKE FOR Y U?

McPherson (Chelmsford, MA) has announced a new vacuum ultraviolet universal spectrophotometer, an optical test system optimized for emitting samples like phosphors or photo- and electro-luminescent crystals. It can measure reflectance, transmission and fluorescence emission over its complete working range, 120 nanometers to 2.2 microns. The sample chamber includes high efficiency toroidal optics for focused excitation and sensitive detection. It can operate purged or under vacuum and can interface to commercial cryogenic and heated sample mounts.

McPherson’s vacuum ultraviolet universal spectrophotometer features easily interchangeable five-position sample holders. Samples index while the system is under vacuum. Spectral excitation and emission wavelengths may be freely set and scanned. A high throughput monochromator with Deuterium and/or Xenon source provides tunable excitation. Emission detection is CW mode; lifetime (persistence) signal acquisition modules are available. For high sensitivity detection the system uses cooled photomultiplier and/or direct detection CCD array detectors.

Quickly Modify Stock Optics

2-3 WEEK DELIVERY

Andrew Fisher Modification Expert

For Free Info Visit http://info.hotims.com/55589-211

sCMOS Cameras With the addition of two new models, PCO (Kelheim, Germany) now provides eight sCMOS-cameras. The new pco.edge 3.1 and pco.edge 4.2LT are now the company’s entry-level cameras. pco.edge 3.1’s features include: 2048 x 1536 pixels resolution; 50 frames per second; 1.1e- med readout noise; 27000 : 1 dynamic range; >60% quantum efficiency; global and rolling shutter readout; and small form factor. pco.edge 4.2LT’s features include: 2048 x 2048 pixels resolution; 40 frames per second; 0.8e- med readout noise; 36000 : 1 dynamic range; >70% quantum efficiency; and a small form factor.

19,500 Stock Optics From EO Catalog Available to Modify!

Popular Modifications:

For Free Info Visit http://info.hotims.com/55589-212

Samarium Oxide Glaze Developed for high-energy pulsed Q-switching infrared laser applications, a new, high-absorption samarium oxide glaze from Morgan Advanced Materials (Windsor, UK) means it is now able to offer three grades of glaze for laser systems. The samarium glaze absorbs radiation at the Nd-YAG lasing wavelength of 1064nm, and its further transitions near 940nm, 1120nm, 1320nm and 1440nm. A significant amount of fluorescent radiation at the lasing wavelength escapes laterally from the laser rod into the surrounding pumping cavity. Absorbing this radiation prevents it from being reflected back into the laser rod, which would in turn stimulate decay from the upper laser transition level, thereby limiting the number of excited ions which can occupy that level.

Applying the glaze to Morgan’s Sintox AL laser pump cavity material produces the high diffuse reflectivity required to achieve uniform illumination of the laser rod surface. Providing typically 98 per cent reflectance in the desired wavelength range, the new samarium oxide glaze matches yellow (GSY) and clear (GSO) glazes between 700nm and 900nm. The optimum reflectance capability across the range of three glazes now spans wavelengths of around 580nm up to 2,000nm.

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1-856-547-3488 www.edmundoptics.com/modify

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Product of the Month Sensirion, Westlake Village, CA, introduced a gas sensor that, according to the company, is the first in the world to be based on multi-pixel technology. This allows the sensor to perceive its surroundings using various receptors that, with the help of intelligent algorithms and pattern recognition, are able to detect the type and concentration of gases. The single sensor is capable of detecting and distinguishing between different gases. It measures 2.45 × 2.45 × 0.75 mm, and can be integrated anywhere. Using the sensor, mobile devices will be able to sense their surroundings in order to measure indoor air quality, determine the alcohol content of a person’s breath, or recognize smells.

For Free Info Visit http://info.hotims.com/55589-120

Product Focus: Materials & Coatings Clear Epoxy

Carbon Nanotube Additive

Master Bond EP62-1LPSP two-part epoxy from Master Bond, Hackensack, NJ, is suited for bonding, sealing, coating, and encapsulation. It bonds to substrates including metals, composites, glass, and many plastics. The optically clear epoxy has a non-critical four-to-one mix ratio by weight, and features an open time of 12-24 hours at ambient temperatures. It is serviceable over a temperature range of -60 to 400 °F. For Free Info Visit http://info.hotims.com/55589-100

High-Temperature Adhesive Cotronics Corp., Brooklyn, NY, offers Resbond™ S5H13 adhesive that features high-temperature resistance to corrosion, common chemicals, thermal shock, and electricity for bonding dissimilar materials in applications up to 500 ºF. It bonds heavy plastic to stainless steel, seals and insulates bipolar electro-cauterizers, and withstands steam sterilization cycles at 375 ºF. It adheres to metals, plastics, high-performance composites, glass, and ceramics, and cures at room temperature.

For Free Info Visit http://info.hotims.com/55589-101

Ceramic Coating HiE-Coat™ 840-M is a black, water-dispersed, ceramic coating from Aremco Products, Valley Cottage, NY that offers emissivity greater than 0.90 at temperatures to 2000 ºF. It is formulated for metal surfaces such as stainless steel, and cures in operation or by heating for 1-2 hours at 200 ºF. The coating cleans up with water and contains no volatile organic compounds.

Zyvex Technologies, Columbus, OH, announced ZNT (Zyvex Nanotube Technology) polymer-modified carbon nanotube additive for host matrices that include epoxies, elastomers, thermoplastics, and aqueous-based solutions. The additive benefits epoxies, rubber blends, and a variety of other materials.

For Free Info Visit http://info.hotims.com/55589-104

Gasket Dymax Corp., Torrington, CT, introduced GA-201 UV/visible, light-curable, tack-free, moisture- and chemical-resistant FIP/CIP gasket for sealing heat-sensitive substrates such as plastic enclosures. The material cures on demand, and acts as a barrier to prevent absorption or penetration of air, dust, noise, liquids, gaseous substances, or dirt.

For Free Info Visit http://info.hotims.com/55589-105

Conductive Foam Available as standard gaskets, custom designs, or sheet stock, 2700 Series conductive foam from Tech-Etch, Plymouth, MA, has X, Y, and Z axis conductivity for EMI shielding attenuation. It is offered with or without pressure-sensitive conductive adhesive covering the entire mounting surface, or with nonconductive adhesive tape in spot application.

For Free Info Visit http://info.hotims.com/55589-110

For Free Info Visit http://info.hotims.com/55589-103

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P R O D U C T SPOTLIGHT USED LABORATORY EQUIPMENT

Flow Meters Omega Engineering, Stamford, CT, offers the FMG980 series insertion electromagnetic flow meters that feature no moving parts for use in dirty applications where debris would foul a mechanical meter.

The flow meters are suited for applications with changing viscosities and pulsating flows.

For Free Info Visit

PhotoMachining, Inc. is a contract laser manufacturer and custom systems builder. We specialize in laser micromachining using lasers from the far IR through the UV. In addition, we sell used, refurbished, and “like new” laboratory equipment including lasers, optics, optical hardware, electronics, microscopes, etc.

Contact sales@photomachining.com, or phone 603-8829944. www.photomachining.com

PhotoMachining, Inc. Free Info at http://info.hotims.com/55589-815

http://info.hotims.com/55589-106

EPOXY PASSES HORIZONTAL BURN TEST

Coin Cell Holder Keystone Electronics Corp., Astoria, NY, offers automatic insertion of 2032 and 2025 lithium coin cells. The rugged holder is suited for retaining cells securely under shock and vibration in high-density applications for PCB requirements. In applications where the battery must be automatically inserted via a vacuum or mechanical pick-and-place device, the “AutoIn” coin cell battery holder is polarized and features dual-spring, gold-plated, phosphor bronze contacts in a glass-filled LCP UL 94V0 base.

For Free Info Visit http://info.hotims.com/55589-108

Embedded Computers ADLINK Technology, San Jose, CA, introduced the MXE-200/200i Series of fanless embedded platforms based on Intel® Atom™ SoC E3845/E3826 processors. They have an aluminum housing for operation in harsh conditions, and combine a controller and gateway functions in one unit.

The computers feature two GbE LAN, two COM, two USB 2.0, and one USB 3.0 host ports; dual mini PCIe slots with one mSATA support; and USIM socket support communication with connections such as WiFi, BT, 3G and LTE. For Free Info Visit http://info.hotims.com/55589-102

ANTI-ALIASING/SIGNAL CONDITIONING TUNABLE FILTER Model 3362 Filter provides two independent channels providing a tuning range from 0.1Hz to 200kHz; selectable pre and post filter gain; selectable low-pass, highpass, band-pass, band-reject functions; selectable Butterworth and Bessel types; selectable single-ended and differential input configurations; and ±10V input and output. All in one box. http://www.krohnhite.com/htm/filters/BenchtopFilters.htm

Krohn-Hite Free Info at http://info.hotims.com/55589-811

DATA ANALYSIS AND GRAPHING SOFTWARE

Flame retardant Master Bond EP90FR-HFL is a toughened epoxy that passes FAR standard 14 CFR 25.853(a). Therefore, it can be considered for use in many specialized aviation applications including aircraft windows, lighting assemblies, and baggage equipment areas, among others. Since it has some flexibility, it is particularly useful for bonding dissimilar substrates. http://www.masterbond.com/tds/ep90fr-hfl

Founded in 1992, OriginLab develops data analysis and graphing software for users in corporations, government agencies, colleges, and universities worldwide. Its flagship products, Origin and OriginPro, provide a comprehensive solution for scientists and engineers at any technical level to analyze, graph, and professionally present data. Origin version 2015 is now available. www.originlab.com/2015

Master Bond

OriginLab Corporation

Free Info at http://info.hotims.com/55589-812

Free Info at http://info.hotims.com/55589-814

PRECISION ORIFICES & FILTERS Bird Precision offers laser-drilled, wire-lapped ruby and sapphire orifices.

• Huge variety of Orifices, www.birdprecision.com sales@birdprecision.com Inserts, Connectors, and Fittings • Unique micron orifices series Control the Flow sizes from .0004" thru .081" • Highly repeatable flow from < .5sccm at 5psi • Extreme wear & chemical resistance • Engineering resources & design guides. Please visit our award-winning website for more information. Bird Precision, Waltham, MA; Tel: 800-454-7369; Fax: 800-370-6308; e-mail: sales@ birdprecision.com; www.birdprecision.com.

THICK & THIN FILM RESISTORS

For over 40 years, MSI has been delivering superior quality products. Absolute tolerances starting at 0.01% and TCR’s at ±2 ppm/C. Applications include medical implantables, military, aerospace, microwave/RF, and telecommunications. Call (508) 6950203, visit www.Mini-SystemsInc.com, or e-mail Info@mini-systemsinc.com

Mini-Systems Inc.

Bird Precision Free Info at http://info.hotims.com/55589-809

Free Info at http://info.hotims.com/55589-813

Free Subscription to Medical Design Briefs Are you involved in the design of medical products?

Get a FREE subscription to Medical Design Briefs at www.medicaldesignbriefs.com/subscribe.

Medical Design Briefs reports on the latest technology advances design engineers can apply to new medical devices, instruments, and systems.

INTRODUCING COMSOL 5.1 COMSOL redefined the engineering simulation market with the release of COMSOL Multiphysics® software version 5.1, featuring the new and revolutionary Application Builder.

COMSOL users can now build applications for use by engineering and manufacturing departments, expanding accessibility to their expertise and to cutting edge simulation solutions. See how at comsol.com/release/5.1

COMSOL, Inc. Free Info at http://info.hotims.com/55589-810

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Upcoming...

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Simulation of Microfluidic Devices Using COMSOL Thursday, May 14, 2015, 2:00 pm ET

Modeling and simulation form a systematic framework for developing and optimizing microfluidic systems. Such simulations often involve coupling multiple physical effects such as single- and multi-phase flow, mixing, dispensing, heat transfer, species transport and diffusion, chemical reactions, surface tension and wetting, electrokinetic effects, and flow interaction with biological material. In this webinar, you will see methods for simulating these phenomena and other microfluidic devices and processes in COMSOL Multiphysics®.

Presenters: Mranal Jain Application Specialist COMSOL

This 60-minute Webinar includes: • Live Q&A session • Application Demo • Access to archived event on demand

Matt Hancock Senior Engineer Veryst Engineering

Please visit www.techbriefs.com/webinar273

Medical 3D Printing and Additive Manufacturing: Going From Why to How

Tuesday, June 9, 2015 – 2:00 pm ET 3D printing has been utilized in the medical industry for over 20 years. In recent years, the number of applications, utilization, and utility have increased exponentially. In this webinar, you will learn the history of medical adoption of 3D printing and additive manufacturing and see specific examples of how technology and material development are changing the medical industry.

Presenter: This 60-minute Webinar includes: • Live Q&A session • Application Demo • Access to archived event on demand

R. Scott Rader, PhD. GM, Medical Solutions Stratasys Ltd.

Please visit www.techbriefs.com/webinar277

On Demand!

Photo-Chemical Machining of Metals…Faster & More Cost Effective Than You’d Think!

Photo-Chemical Machining (PCM), or photo-etching of metals, is a mature process used to create very accurate metal components.

PCM can produce highly complex parts with very fine details — quickly, accurately, and economically. Photo-etching is a cost effective alternative to stamping, punching, laser cutting, water jet cutting, or electrical discharge machining (EDM) of thin gauge precision parts.

Presenter: Robert D. Ashman National Sales Manager – Precision Products Photofabrication Engineering, Inc.

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New Innovations in 3D Measurement Software: Increased Portability for Laser Tracker Applications

One of the primary advantages of using Laser Tracker Technology is the ability to achieve precise accuracy over large measurement volumes. New innovations in 3D Measurement Software deliver software that is both tablet-compatible and able to be operated by voice-command. These new features enable users to easily carry their 3D Measurement Software and allow for hands-free operation, resulting in a streamlined workflow.

Presenter: Les Baker Senior Applications Engineer FARO Technologies, Inc.

Please visit www.techbriefs.com/webinar271

On Demand!

Bridging the Gap:

Flight-Based Evaluations Soar to New Heights with Advanced Manufacturing Additive manufacturing is being heralded as a disruptive technology in aerospace — it’s changing the way aircraft are being manufactured. Area-I, an aerospace engineering company, has partnered with Stratasys Direct Manufacturing to create PTERA, an unmanned Prototype Technology Evaluation and Research Aircraft to help fill the gap between wind tunnel and manned flight testing. In this webinar, engineers from both teams discuss how additive manufacturing helped PTERA get off the ground.

Presenters: Josh Steele Aerospace Engineer Area-I

Harold Myer Project Engineer Stratasys Direct Manufacturing

Please visit www.techbriefs.com/webinar274

On Demand!

Case Studies with Poly(p-xylylene) Polymers: Solving Friction Challenges and Protecting Critical Components

Enhance safety, reliability, and performance in demanding environments. Case studies have been shared that demonstrate how challenges found in many highly engineered sectors including Medical Devices, Aerospace, Automotive, Defense, and Power Generation have been overcome.

Presenter: Kevin Ustynik Staff Engineer & Quality Manager Surface Technologies Division Curtiss-Wright

Please visit www.techbriefs.com/webinar261

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NASA’s Technology Transfer Program NASA’s R&D efforts produce a robust supply of promising technologies with applications in many industries. A key mechanism in identifying commercial applications for this technology is NASA’s national network of laboratories and business support entities. The network includes ten NASA field centers, and a full tie-in with the Federal Laboratory Consortium (FLC) for Technology Transfer. To explore technology transfer, development, and collaboration opportunities with NASA, visit technology.nasa.gov.

NASA’s Technology Sources If you need further information about new technologies presented in NASA Tech Briefs, request the Technical Support Package (TSP) indicated at the end of the brief. If a TSP is not available, the NASA field center that sponsored the research can provide you with additional information and, if applicable, refer you to the innovator(s). These centers are the source of all NASA-developed technology.

Ames Research Center Selected technological strengths: Information Technology; Biotechnology; Nanotechnology; Aerospace Operations Systems; Rotorcraft; Thermal Protection Systems.

David Morse (650) 604-4724 david.r.morse@nasa.gov

Kennedy Space Center Selected technological strengths: Fluids and Fluid Systems; Materials Evaluation; Process Engineering; Command, Control, and Monitor Systems; Range Systems; Environmental Engineering and Management.

David R. Makufka (321) 867-6227 david.r.makufka@nasa.gov

Armstrong Flight Research Center Selected technological strengths: Aerodynamics; Aeronautics Flight Testing; Aeropropulsion; Flight Systems; Thermal Testing; Integrated Systems Test and Validation.

Laura Fobel (661) 276-3967 laura.j.fobel@nasa.gov

Langley Research Center Selected technological strengths: Aerodynamics; Flight Systems; Materials; Structures; Sensors; Measurements; Information Sciences.

Kathy Dezern (757) 864-5704 kathy.a.dezern@nasa.gov

Glenn Research Center Selected technological strengths: Aeropropulsion; Communications; Energy Technology; High-Temperature Materials Research.

Kimberly A. Dalgleish-Miller (216) 433-8047 kimberly.a.dalgleish@nasa.gov

Marshall Space Flight Center Selected technological strengths: Materials; Manufacturing; Nondestructive Evaluation; Biotechnology; Space Propulsion; Controls and Dynamics; Structures; Microgravity Processing.

Terry L. Taylor (256) 544-5916 terry.taylor@nasa.gov

Goddard Space Flight Center Selected technological strengths: Earth and Planetary Science Missions; LIDAR; Cryogenic Systems; Tracking; Telemetry; Remote Sensing; Command.

Nona Cheeks (301) 286-5810 nona.k.cheeks@nasa.gov

Stennis Space Center Selected technological strengths: Propulsion Systems; Test/Monitoring; Remote Sensing; Nonintrusive Instrumentation.

Duane Armstrong (228) 688-2180 curtis.d.armstrong@nasa.gov

Jet Propulsion Laboratory Selected technological strengths: Near/DeepSpace Mission Engineering; Microspacecraft; Space Communications; Information Systems; Remote Sensing; Robotics.

Dan Broderick (818) 354-1314 daniel.f.broderick@jpl.nasa.gov Johnson Space Center Selected technological strengths: Artificial Intelligence and Human Computer Interface; Life Sciences; Human Space Flight Operations; Avionics; Sensors; Communications.

John E. James (281) 483-3809 john.e.james@nasa.gov

NASA HEADQUARTERS Daniel Lockney, Technology Transfer Program Executive (202) 358-2037 daniel.p.lockney@nasa.gov Small Business Innovation Research (SBIR) & Small Business Technology Transfer (STTR) Programs Rich Leshner, Program Executive (202) 358-4920 rleshner@nasa.gov

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Publisher ........................................................Joseph T. Pramberger Editorial Director............................................................Linda L. Bell Editor, Photonics Tech Briefs...................................Bruce A. Bennett Technical/Managing Editor ............................................Ted Selinsky Technical Writers ............................................................Shirl Phelps ...............................................................................Nick Lukianoff Managing Editor, Tech Briefs TV ..................................Kendra Smith Associate Editor ..............................................................Billy Hurley Production Manager.................................................Adam Santiago Assistant Production Manager..................................Kevin Coltrinari Creative Director ...........................................................Lois Erlacher Designer...............................................................Bernadette Torres Marketing Director.................................................Debora Rothwell Marketing Communications Manager ..........................Monica Bond Digital Marketing Coordinator .................................Kaitlyn Sommer Audience Development Director .........................Marilyn Samuelsen Audience Development Coordinator ...........................Stacey Nelson Subscription Changes/Cancellations ....................nasa@omeda.com NASA tech briefs are provided by the National Aeronautics and Space Administration, Innovative Partnerships Program: Administrator ...................................................Charles F. Bolden, Jr. Chief Technologist ....................................................David W. Miller Technology Transfer Program Executive ....................Daniel Lockney TECH BRIEFS MEDIA GROUP, AN SAE INTERNATIONAL COMPANY 261 Fifth Avenue, Suite 1901, New York, NY 10016 (212) 490-3999 FAX (212) 986-7864 Chief Executive Officer...................................Domenic A. 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Europe — Central & Eastern .......................................Sven Anacker ..............................................................................49-202-27169-11 Europe — Western .........................................................Chris Shaw ...............................................................................44-1270-522130 Hong Kong.........................................................................Mike Hay 852-2369-8788 ext. 11 China...........................................................................Marco Chang 86-21-6289-5533 ext.101 Taiwan.............................................................................Howard Lu 886-4-2329-7318 Integrated Media Consultants....................................Patrick Harvey ................................................................................ (973) 409-4686 Angelo Danza .................................................................................(973) 874-0271 Scott Williams .................................................................................(973) 545-2464 Rick Rosenberg .................................................................................(973) 545-2565 Todd Holtz .................................................................................(973) 545-2566 Corporate Accounts........................................................Terri Stange ................................................................................ (847) 304-8151 Reprints...........................................................................Jill Kaletha ........................................................................(866) 879-9144, x168

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Advertisers Index Reader Service Number

Company

For free product literature, enter advertisers’ reader service numbers at www.techbriefs.com/rs, or visit the Web site listed beneath their ad in this issue.

Advertisers listed in bold-face type have banner ads on the NASA Tech Briefs Web site — www.techbriefs.com

Page

Reader Service Number

Company

Page

Allmotion, Inc. ..............................................784 ..........................44

Proto Labs, Inc. ..............................................762, 803 ............13, 67

Altair..............................................................754 ............................1

RDP Electronics ..............................................863 ..........................60

Associated Research, Inc. ................................770 ..........................27

Renishaw Inc. ................................................768 ..........................22

ATI Industrial Automation ..............................773 ..........................30

SAE International............................................804 ..........................69

AutomationDirect ..........................................799 ..........................21

SAMPE 2015 ..................................................795 ..........................56

Avago Technologies ........................................900 ......................9A-B

Sealevel Systems, Inc.......................................771 ..........................28

Bird Precision..................................................809 ..........................75

SEMICON West 2015......................................782 ..........................61

Boyd Coatings Research Co. Inc. ....................786 ..........................47

Smalley Steel Ring Company ..........................783 ..........................43

CAMX 2015 ..................................................795 ..........................56

Spectrogon US, Inc.........................................807 ..........................72

COMSOL, Inc. ............................................765, 810 ..........17, 75

Stanford Research Systems, Inc.......794, 796, 797 ..............55, 57, 59

Create The Future Design Contest ..............................................41, 9a

Stratasys Direct Manufacturing ................757 ......................4-5

Dataforth Corporation ....................................775 ..........................32

TE Connectivity ..............................................785 ..........................45

DEWESoft, LLC ..............................................764 ..........................15

Tech Briefs TV..................................................................................40

Dewetron Inc. ..........................................769 ........................25

Tech-Etch, Inc. ..............................789, 790, 793 ..............49, 51, 53

Digi-Key Corporation ................................753 ......COV I, COV II

The Big M Event ............................................798 ..........................62

Dymax Corporation ........................................766 ..........................19

VTI Instruments Corp. ....................................777 ..........................34

Edmund Optics ..............................................808 ..........................73 Edwards Vacuum............................................781 ..........................39 EMCOR Government Services ..........................755 ............................2 Evanescent Optics ..........................................802 ..........................66 FLIR Commercial Systems ........................780 ........................37 Hamamatsu....................................................800 ..........................65 IHS GlobalSpec ..........................................767 ........................23

Sensor Technology Ad Index ams AG ........................................................740 ..........................1 ATI Industrial Automation ............................862 ........................20 AWAIBA ......................................................748 ........................16 DTS ..............................................................750 ........................17 Framos GmbH ..............................................864 ........................18 Kaman Precision Products ............................743 ..........................5

Imagineering, Inc. ..........................................756 ............................3

Massa Products Corp. ..................................751 ........................19

Keysight Technologies ..............761, 772, 774 ............11, 29, 31

Measurement Computing Corp...............744 ........................7

Krohn-Hite Corporation ..................................811 ..........................75

Merit Sensor ................................................741 ..........................2

Lambda Research Corporation ........................806 ..........................72

Micro-Epsilon Messtechnik GmbH ................739 ..................COV II

Master Bond Inc. ......................788, 801, 812 ............48, 66, 75

Renishaw Inc. ..............................................745 ..........................9

MathWorks ....................................................758 ............................7

Santest Co., Ltd. ..........................................746 ........................13

MicroCare ......................................................791 ..........................52

Silicon Sensing Systems Ltd. ..........................749 ........................16

Miller-Stephenson Chemical Co. ......................787 ..........................48 Minalex Corporation ......................................763 ..........................38 Mini-Systems, Inc. ..........................................813 ..........................75 Mitsubishi International Corporation ..............805 ..........................71

Steute Industrial Controls, Inc. ......................752..................COV IV Tadiran Batteries ..........................................742 ..........................3 Tech Briefs TV........................................................................COV III Watlow Electric Mfg. Co. ..............................747 ........................15

Morehouse Instrument Company ....................779 ..........................36

Supplement to NASA Tech Briefs 2, 3, and 4.

National Instruments ......................................817 ..................COV IV Newark/element14 ........................................816....................COV III Newcomb Spring Corporation ........................792 ..........................52 Newport Corporation ..............................759 ..........................8 Omega Engineering ..................................776 ........................33 OriginLab Corporation ....................................778, 814 ............35, 75 Parker Hannifin Corp.................................760 ..........................9 PhotoMachining Inc. ......................................815 ..........................75 NASA Tech Briefs, May 2015

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SPINOFF

Spinoff is NASA’s annual publication featuring successfully commercialized NASA technology. This commercialization has contributed to the development of products and services in the fields of health and medicine, consumer goods, transportation, public safety, computer technology, and environmental resources.

NASA’s UV Radiation Research Keeps Sun Worshipers Safe Studying radiation effects on spacecraft led to a personal Sun exposure monitor.

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o understand the Sun’s impacts on sunlight can cause sunburn, premature Future Design Contest, presented by Earth, NASA initiated the Living with aging, and skin cancer.

Tech Briefs Media Group, the publishers a Star program in 2001, and began develTo gauge how much sunlight is too of NASA Tech Briefs. oping a key research satellite: the Solar much, scientists have developed what’s Buoyed by the initial reception, the Dynamics Observatory (SDO). One of known as the erythemal UV index, pair formed SunFriend Corporation and the instruments created for the SDO was which highlights the durations at which moved forward with further developthe Extreme Ultraviolet Variability UV wavelengths, when set at certain ment. In April 2014, after receiving posExperiment (EVE), tasked with measurpower quotients, will likely cause erytheitive reviews in trade shows the previous ing extreme ultraviolet (UV) radiation, ma, or reddening of the skin due to year, the UVA+B SunFriend was put on which plays a key role in atmospheric inflammation. Wouldn’t it be great, the market. heating and satellite drag. In 2005, Aslam thought, to develop some kind of UVA+B SunFriend activity monitor Goddard Space Flight Center scientist device that measures UV exposure in a comes at a time, Edgett said, when one Shahid Aslam joined other researchin five people in the United States ers in developing EVE. will get skin cancer in his or her lifeA focus of Aslam’s work was expertime. On the flip side, in some imenting with different ways of measregions of the world, vitamin D defiuring extreme UV radiation. Silicon ciency is considered a pandemic. semiconductors have been used traTo use SunFriend, a user first ditionally as detectors, but a drawselects his or her level of skin sensitivback is they take in both UV and visiity on an 11-point scale, with 1 indible light. Filters are used to isolate cating the highest level of sensitivity the ultraviolet signal, but the results and 11 the lowest. The device is then aren’t ideal. To sidestep the filtration worn face-up on the wrist and left process, the team looked into wideuncovered. Throughout the day, as band gap semiconductors: chemical UVA and UVB light hits the embedcompounds that detect a narrower ded semiconductor compound, it range of wavelengths on the electroproduces photocurrents indicative of magnetic spectrum. In particular, the how much radiation is coming in. A team worked with compounds that Inspired by his work on EVE, Goddard scientist Shahid microchip processes that current, Aslam conjured up the idea for what is now UVA+B detect only UV light. taking into account radiation SunFriend, a UV light-detecting activity monitor that It was early on in the project while informs people when they’ve reached their maximum strength, the ratio of UVA to UVB experimenting with different com- recommended daily dose of sunlight. light, and the selected level of skin pounds that Aslam noticed that a few sensitivity. When the maximum recof them detected bands of wavelength in way that allows people to manage their ommended daily dose of UV light is the UV spectrum that held special signifdaily Sun intake? reached, the LEDs on the face of the icance for human health — areas where He brought the idea up with marketing device will flash. Aslam said, “At that humans experience biological effects due guru Karin Edgett, and the pair moved point, you apply sunscreen, go indoors, to Sun exposure. Of the many types of forward with developing the product. In or put on clothing.”

UV light, UVA and UVB play important his spare time, Aslam began working on Although SunFriend is still very new roles in health since their rays can pass the technical development, which includto the market, the company is already through the atmosphere and make coned formulating algorithms and homing working on increasing its functionality, tact with Earth’s surface. Whether they’re in on a proficient detector compound; such as implementing Bluetooth techfriend or foe depends on the amount of Edgett tackled marketing and branding. nology so that information can be comexposure: Our bodies need UV light to The result — a UV light-detecting activity municated to users’ smartphones for produce vitamin D, critical to building monitor — received recognition in 2011 record-keeping and statistics. bone density and supporting brain and when it won first place in the Consumer Visit http://spinoff.nasa.gov/Spinoff2015/ immune system function, but too much Products category in the Create the cg_5.html.

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