Raja Kaliappan1, Rachael Jones2, Karl J Rockne1 1Civil and Materials Engineering and 2Environmental and Occupational Health Sciences Funding from the Centers for Disease Control (CDC)
Problem Statement and Motivation •
This study attempts to link adverse pregnancy outcomes, birth defects and childhood leukemia to pre/postnatal exposure to atrazine and nitrate through drinking water
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Atrazine is a widely applied herbicide in the cultivation of corn, sorghum and sugarcane
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Atrazine is transported by surface runoff and infiltration leading to surface water and ground water contamination and subsequent human exposure through drinking water
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Atrazine is a known endocrine disruptor. Several studies show limited evidence of atrazine exposure to adverse reproductive/birth outcomes and childhood leukemia
Key Achievements and Future Goals
Technical Approach •
Collection of county level agrochemical data in drinking water from SIDWIS and adverse reproductive/birth outcomes from birth certificates from eight Midwestern states: Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio and Wisconsin
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Annual and monthly atrazine and nitrate exposure estimates
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Identification of potential confounders, correlation and multivariable regression (health-linkage) analysis of county level data
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Cluster detection, mixed effects model and geographically weighted regression using spatial statistical methods
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Drinking water data analysis shows that peak atrazine concentrations occur in the months of April to August, consistent with known application patterns
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County level annual and monthly average atrazine/nitrate exposures have been quantified for inclusion in a GIS database for spatial mapping
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These data will be linked with adverse pregnancy outcomes from public health data (birth records, birth defects, and cancer registries) for an environmental epidemiological study
Asha Rani, Azivy Aziz, Karl J. Rockne Department of Civil & Materials Engineering, University of Illinois at Chicago
Problem Statement and Motivation Sources of mercury to wastewater treatment systems are primarily from industrial sources and dental operations. Studies conducted by the University of Illinois at Chicago (UIC) revealed that a typical dental clinic can generate up to 4.5 g aqueous Hg waste/day. Our previous research demonstrated that elemental Hg from removed dental amalgam fillings is transformed to the highly toxic methyl Hg (MeHg) by sulfate-reducing bacteria (SRB).
Dental trap FLX amplicon pyrosequencing
Sequence analysis
• • •
Key Achievements and Future Goals
Technical Approach • • • • • • • •
Dental wastewater (DWW) collection from dental traps Determination of total Hg and MeHg levels using mercury analyzer Metagenomic DNA isolation from samples Identification of novel bacteria by 16S rRNA gene sequencing Automated ribosomal intergenic spacer analysis (ARISA) on metagenomic DNA Quantitative-PCR for estimation of total eubacteria versus SRB High-throughput FLX amplicon pyrosequencing of all the samples to characterize total microbial communities Phylogentic analysis and identification of novel lineages
Key questions will be answered by this research: Where is Hg methylated? In the mouth or in the DWW system? How many and which Hg methylating bacterial species exist? What microbial communities can exist in the highly toxic DWW?
• • • • •
Metagenomic DNA isolated from Hg contaminated DWW 16S rRNA gene has been amplified for pyrosequencing Q-PCR optimized for total eubacteria and SRB ARISA and pyrosequencing analysis in progress Phylogenetic analysis for identification and characterization of microbial community composition in progress
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Future goal to employ these techniques to understand microbial community structures in other high Hg environments worldwide • Minamata Bay, Japan: Estuarine • Soda lakes in Western USA: (pH 13) • Solar saltern in Spain: (>35% salt) • Hg mines, SW Alaska: Freshwater, cold
Kouros Mohammadian, PhD, S. Yagi, J. Auld, and T.H. Rashidi (PhD Candidates), CME, UIC Primary Grant Support: NIPC/CMAP, FACID, and IGERT (NSF) Synthetic Population
Activity Generation Model
Problem Statement and Motivation
Synthetic City
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Traditional four step travel demand models are widely criticized for their limitations and theoretical deficiencies
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These problems lead the model to be less policy sensitive than desired
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Travel is derived from participation in activities. This fact is not accounted for in 4-step models. Therefore, there is a need for a better modeling approach
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An activity-based microsimulation travel demand model is considered that simulates activity schedules for all individuals
Activity Scheduling Model
ADS/HTS Surveys
Synthesized Population
Policy scenarios
Executed Schedules Activity-Based Modeling
Activity/Travel Microsimulation
Activities/ Tours/Trips
Travel Demand
Highway/Transit Network Assignment Policy Analysis
Vehicle/Fuel Condition
Emission Model
Key Achievements and Future Goals
Technical Approach • • •
• •
The modeling framework utilizes both econometric and heuristic (rulebased) approaches All human activities are related to broad project categories which have a common goal (e.g., Work, School, Entertainment, etc.) and tasks and activity episodes that are required to reach that goal are modeled Activity participation is modeled at household/individual level (microsimulation) Explicit representation of time/space of occurrence for all travel episodes, linked to associated activities Activity scheduling model is linked to a population synthesizer, rescheduling and resource allocation models, and a regional network microsimulation and emission models
• • • •
• •
A comprehensive multi-tier activity-based microsimulation modeling system is developed. A new population synthesizer is developed. Activity scheduling/rescheduling decision rules are developed and applied to adjust the simulated daily activity patterns. Intra-household interaction rules are developed and applied to account for joint activity generation and household maintenance activity allocation problems. Transferability of activity scheduling/rescheduling decision rules across different spatial and temporal contexts are evaluated. The microsimulation model is applied to evaluate future transportation policy scenarios.
Karl J. Rockne, Department of Civil and Material Engineering An Li, Environmental and Occupational Health Sciences Neil C. Sturchio, Earth and Environmental Sciences Primary Grant Support : US. Environmental Protection Agency – Great Lakes National Program Office
Problem Statement and Motivation •
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•
Key Achievements and Future Goals
Technical Approach •
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Sediment samples collected through surface Ponar grabs, along with 25cm deep sediment cores retrieved at selected sites using an Ocean Instruments MC-400 “Spyder” Multi Corer. Physical/chemical characterization of sediment including elemental analysis of sediment organic matter, and pore-water ion composition.
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Age dating of sediments through radionuclide analysis and Gamma emission spectrometry.
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Chemical analysis for PBTs including polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), pesticides, and polybrominated diphenyl ethers (PDBE).
The mission of GLSSP is to investigate the presence of persistent, bioaccumulative, and toxic (PBT) chemicals, and reveal the spatial distribution and temporal trend of PBT pollution in the Great Lakes sedimentary record. Sediment is one of the largest depository matrices of pollutants in aquatic systems, and often acts as a secondary source even long after discharge ceases. Properly retrieved and preserved sediment samples can provide information valuable to the effective management and remediation of the contaminated water bodies. Although the Great Lakes have been one of the most investigated large freshwater systems, the number of region-wide studies on both legacy and emerging chemical pollutants in the sediment is still limited. A better understanding of the transport and transformation of PBT chemicals deposited in the sediments demands detailed characterization of the sediments and the over laying water column.
• • • •
Successful sediment sampling of deepest point in Lake Superior (385m depth) achieved, May 2011 Genetic assay of water column microbial genomes through pyrosequencing Investigation of in-situ dehalogenation of PBTs in sediment. Analysis of sediment mercury (Hg) and potential Hg-methylation.
Sampling Year Summer, 2010 Summer, 2011 Summer, 2012 Summer, 2013 Summer, 2014
Targeted Great Lakes, Bays and Rivers Lake Michigan, Green Bay Lake Superior Lake Huron, Lake St. Clair, Detroit River Lake Ontario, St. Lawrence River Lake Erie including Niagara River
# of Cores 11 11 10 8 7
# of Grabs 26 28 40 40 30
Sybil Derrible, Assistant Professor, Department of Civil and Materials Engineering Primary Grant Support: University of Illinois at Chicago
Problem Statement and Motivation •
With increasing urbanization and growing environmental concerns, public transportation systems will expand in cities all over the world.
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Current planning practices have limitations, and in particular they omit the topological network feature of transit.
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Inspired from complex systems thinking, the first step is to identify any inherent patterns, common to all transit systems.
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The second step is then to explain any differences in metro network topologies.
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Eventually, we should aim to “steer” relevant metrics in desirable directions for more sustainable and livable cities.
Key Achievements and Future Goals
Technical Approach •
Characterized metro systems according to their State, Form and Structure
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Developed a methodology to analyze metros as complex systems
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Observed hidden yet relevant patterns common to all metro systems
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Studied the relationship between ridership in network properties.
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Future goals: apply a similar methodology to all transportation modes.
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For more information, visit our webpage: http://www.uic.edu/~derrible/
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Translate a metro system into a network with a set of nodes (transfer stations and termini) and links (rails). • Calculate relevant topological metrics such as degree of connectivity, cyclomatic number, scaling factor, betweenness centrality. • Plot and observe the evolution of these metrics with network size. • This figure shows one metric (quad. coeff. of cumulative distribution of betweenness centrality) as a function of size, clearly depicting two regimes in metro network topologies.
Farideddin Peiravian, PhD Candidate, and Sybil Derrible, Assistant Professor Department of Civil and Materials Engineering Primary Grant Support: University of Illinois at Chicago
Problem Statement and Motivation
Population
Buildings
Roads
Intersections
City of Chicago Feature Pop+Empl Density Floor Area Density Road Length Density Intersection Density
Radius (km)
Fractal Dimension
R2
tstat
Significant?
1 to 10 11 to 21 1 to 10 11 to 21 3 to 10 11 to 21 3 to 10 11 to 21
1.36 0.73 1.20 0.70 0.21 0.09 0.39 0.19
0.99 0.98 0.99 0.99 0.98 0.95 0.98 0.95
-77 -22 -66 -45 -13 -11 -15 -13
Yes Yes Yes Yes Yes Yes Yes Yes
The characteristics of an urban system is the aggregated outcome of numerous individual and collective choices during its history. The idea is that no matter how a system has evolved, from a larger perspective it has an inherent order, a characteristic of complex systems. The spatial spread of various elements of an urban system exhibit selfrepeating patterns. Although such elements are not directly comparable, using a fractal approach to analyze them offers the provision of a measurable metric, i.e. fractal dimension, enabling one to gage how they co-exist and interact within the built environment. Objectives • Analyze the characteristics of different elements of an urban system • Determine and compare the fractal representations of those elements • Explore the reasons behind such similarities and differences
Key Achievements and Future Goals
Technical Approach • • • • • • • • • • • • •
Selected Chicago for case study, and the “Loop” (CBD) as its center Chose Population+Employment, Gross Floor Area, Road Length, and Number of Intersections as representative elements of the city Obtained the data and removed uninhabited areas (water bodies, etc.) Created 1 km equi-distance rings around the center Clipped the data according to the intersecting ring Calculated the amount of each feature within each ring Created buffers around the center with radial increments of 1 km Calculated the density of each feature within the buffers Plotted the densities versus radius and observed the “Power Law” trend, which is a manifestation of fractal property Plotted log-log diagram of density of each feature versus radius Performed piecewise linear fitting of data based on trend changes Calculated the fractal dimension of each linear segment Performed statistical significance tests to validate the results
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Showed that cities (example: Chicago) are complex systems in which dissimilar features indeed possess inherent order and fractal characteristics which can be captured, quantified, and compared Showed that the spreads of Population+Employment as well as Gross Floor Area in a same city are directly correlated and in fact have very similar fractal dimensions Showed that the distributions of the road network as well as the intersections within a city are directly correlated and in fact have very similar fractal dimensions Used fractal properties to identify the hidden changes in the topology of the urban system, which was otherwise hard to identify. Presented a fractal approach to the characterization of complex urban systems, which can be used in future to identify system deficiencies.
Craig Foster, Civil and Materials Engineering, B.V. Venkatarama Reddy, IISc., Bangalore, India Primary Grant Support: NSF
Problem Statement and Motivation • • •
Though they have been used for millennia, the structural behavior of earthen materials such as rammed earth and stabilized mud block is not well understood. Such materials may fail by diffuse plasticity, fracture along weak interfaces, and fracture through the bulk material. Advanced finite element modeling can help elucidate structural failure modes, limit states, and help design safer, more economical structures.
Stabilized mud block (top, left) and rammed earth (right) buildings
Key Achievements and Future Goals
Technical Approach • • •
Using enhanced finite elements with embedded discontinuities, we can simulate the changing stress and strain as walls are loaded, and model fractures passing through the bodies. The complex material behavior will be fit to bulk and interface constitutive models. Experiments for parameter determination and validation performed with the help of Professor BVV Reddy’s group at IISc, Bangalore.
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Development of material models and implementation to finite element codes Experimental determination of material properties Validation of large-scale bending and shear experiments Examination of shear behavior of earthen walls Fracture of a stabilized mud block wall in bending
Yield surface of continuum plasticity model
Yield surface for fracture model
Investigators: Kouros Mohammadian, J. Auld, and B. Karimi, CME; and K. Kawamura, CUPPA Primary Grant Support: Illinois Department of Transportation
Problem Statement and Motivation
Legend HSR station HSR line
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Currently, there are four statewide long-distance travel modes competing across Illinois and its neighboring states: Car, Amtrak, Bus, and Airplane. Each of these travel modes, depending on their attributes such as fare and travel time, attract a specific share of passenger ridership.
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High-speed (up to 220mph) train is studied as a new alternative travel mode to estimate what percentage of travelers would choose it as their travel mode and how it would affect other modes.
Model Region
Key Achievements and Future Goals
Technical Approach •
A micro-simulation approach was employed to simulate all long distance trips across the study area at person level for the base year and future target year.
Census
Land Use
Synthetic Population
Long Distance Trip Generation
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Total annual ridership of high-speed train was estimated for the base year and for a target year.
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High-speed train mostly attracts travelers from car and airplane modes.
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An economic model to maximize revenue while maintaining high ridership was also developed and various fare structures were examined.
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The simulation tool is used to examine various policy scenarios.
HH Survey Trip Distribution Intercept Surveys
Mode Choice
Ridership
Investigators: Kouros Mohammadian and Zahra Pourabdollahi, CME Primary Grant Support: Illinois Department of Transportation (IDOT) & National Center for Freight and Infrastructure Research and Education (CFIRE)
Problem Statement and Motivation •
An efficient freight transportation system could have considerable positive impacts on the economy
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Freight models and related public policy tools are far behind the logistics and technological advances
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Freight transport modeling frameworks should be revised in a way that captures the basis of decision making process across the supply chain
Key Achievements and Future Goals
Technical Approach •
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Develop activity based microsimulation freight transportation framework which simulates decision making process in freight market at a very disaggregate level
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Incorporate behavioral logistics choice models (supplier selection, shipment size choice, mode choice, shipping chain choice) into the framework
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Simulate the commodity flow between each pair of firms and determines characteristics of each individual shipment
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Internet-based establishment survey is used to gain insight into decision making process and model logistics choices
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Behavioral logistics choice models are developed in the design process to improve freight movement analysis A detailed dataset is collected through the internet-based establishment survey and is used to develop logistics choice models A traffic simulation module will be incorporated directly in the microsimulation model Data simulation techniques are also being improved Simulation results should be validated with the real observed data Policy scenarios should be developed and examined
Nabin Kafle, PhD student and Bo Zou, Assistant Professor Department of Civil and Materials Engineering
Problem Statement and Motivation • Flight delay is a serious problem in the US and causes airlines and passengers tens of billion dollars each year • A significant portion of flight delay stems from delay propagation from earlier flights, but the formation mechanism and the influencing factors are not well understood
DFW
12:50
86
2 14:03
20:40 20:42
21:30
22:56
13:04
14
DCA 16:25 16:42 17:10 17
8
17:18
LAX
00:30
01:35
65
Technical Approach • Formulation and application of a flight-level analytical model to trace the formation of initial delay and how initial delay of an early flight propagates into the subsequent flights throughout a day • Development of flight propagation performance metrics based on the initial delay and delay propagation results from the analytical model • Estimation of truncated regression models to quantify the impacts on delay propagation of an aircraft of system –wide operational performance and buffer times on the ground and in flight schedules
• This research contributes to enhancing the research community’s modeling capability for flight delay propagation and enriching the understanding of spatial-temporal characteristics of the formation and propagation of flight delays in the US
Key Achievements and Future Goals • A new framework for analyzing flight delay propagation is established • The framework is successfully applied to the US domestic network to identify the delay propagation patterns
0
23 13:40
600000
11:10
Minutes 400000
DEN
200000
20 10:50
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 Hours of day
New Departure Delay
• Important policy implications are derived from the modeling outputs
Propagated Arrival Delay
Ahmadreza Talebian, PhD Student and Bo Zou, Assistant Professor Department of Civil and Materials Engineering Grant Support: Illinois Department of Transportation (through Urban Transportation Center)
Problem Statement and Motivation • The state of Illinois has launched the High Speed Rail project connecting Chicago and St Louis using track infrastructure shared by passenger and freight rail • It is important to understand the costs and benefits of different stakeholders (travelers, shippers, passenger rail agency, freight railroads) on the shared corridor • This research aims to develop an integrated planning model for optimal rail service to enhance stakeholders’ and policy makers’ understanding of the costs and benefits and engagement in HSR development
Technical Approach • Formulate hyper-graph based binary integer programs to determine optimal train schedules that minimize: 1) System total cost encompassing both passenger and freight side costs 2) Passenger- and freight-side cost sequentially given that HSR has higher priority • Develop efficient solution procedures to solve the optimal trains schedules
One of the optimal train schedules
Key Achievements and Future Goals • Optimal train schedules for the future Chicago-St Louis HSR corridor are generated under a variety of service conditions • Evaluation of the impact of speed heterogeneity and service frequency on system overall performance, and welfare distribution among different parties • Exploration of best options for future infrastructure investment to accommodate future demand growth
Maen Farhat, Momenur Rahman, Mustapha Ibrahim and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: Utility Concrete Products (UCP)
Problem Statement and Motivation •
•
•
Key Achievements and Future Goals
Technical Approach •
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•
• •
Perform experimental study on a 20 ft. high, 166 in. wide full scale prototype (TPCCRW) to asses the strength and service behavior of the wall: Identify the optimum methods and stages of fabrication and prepare an advanced instrumentation and monitoring system that will allow to examine the behavior of the wall at different locations. The TPCCRW was tested experimentally by soil backfilling to simulate real life applications followed by applying load scenarios (4 different tests) reaching 200 kips by using hydraulic actuators. Conduct a finite element analysis using ANSYS package. The nonlinear analysis is carried out imitating the exact construction sequence of a retaining-wall backfills and surcharge loads.
Totally Precast Concrete Counterfort Retaining Wall (TPCCRW) system is an innovative solution to the growing need to develop sustainable retaining wall systems. It provides means for fast track construction that would significantly cut off the time of the construction and erection processes. It is designed to satisfy the code requirements for strength, serviceability, durability and constructability within the least possible cost and the maximum possible safety margins. The fully precast retaining wall system consisted of the face panel and 3 counterforts fabricated as a single entity and assembled with the precast base slab. From each counterfort, 5 headed anchors were extended and grouted in the base slab.
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The anchors, being the most critical component, succeeded to maintain serviceability, and ultimate strength requirements per AASHTO LRFD. The wall deflection in the middle (H/2) did not exceed 0.2 in. and did not exceed the allowable limits. An accurate finite element model capable of predicting the performance of TPCCRW was calibrated with the acquired experimental data using ANSYS software. A comprehensive design for the TPCCRW meeting the requirements of AASHTO LRFD was performed. Future parametric study using the validated finite element model. Additional experimental Investigation of the performance of the headed anchors when subjected to pullout load.
Ibrahim Lotfy, Maen Farhat and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: NURail Center (U.S. DOT-RITA)
Problem Statement and Motivation •
• 13,000
Ultimate Pullout Load, lbs
12,000 11,000 10,000 9,000 8,000 7,000
6,000 Setup A
Setup B Setup C Setup Type
Setup D
0.5
1 2 Stroke (in./min)
73oF 100oF 125oF Temperature (oF)
Key Achievements and Future Goals
Technical Approach Striving to assess the feasibility of implementing HDPE crossties in rail applications, this study examined the behavior of the fastening system. I. Perform experimental testing as per AREMA specifications: • Investigate the behavior of the fastening system components of HDPE crossties under different loading, temperatures and setup conditions (spike pullout, spike lateral resistance and fastener uplift).
II. Conduct a finite element analysis using ANSYS: • Develop a modelling technique capable of properly simulating the interactions between each component in the system along with its effect on the HDPE crosstie.
High Density Polyethylene (HDPE) is a green, recyclable, and environmental friendly material. It has structural and economical advantages which grant it a competitive edge among other alternatives in the rail market such as wooden and concrete crossties The implementation of the new recycled Plastic railroad crossties would improve the railroad industry public image as a green, sustainable industry. The recycled products are manufactured with plastic waste that otherwise would be landfilled which reduces the waste products and additionally eliminates any pollution or deforestation. Moreover, Recycled, HDPE crossties are light, workable, easy to transport and handle, can overcome the main issues facing other materials and can replace wooden crossties on a one-to-one basis without the need for special installation or heavy equipment.
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•
• • •
The fastening system components satisfied and surpassed the AREMA requirements for polymer composite crossties in terms of fastener uplift and spike pullout and lateral restraint. An accurate finite element model capable of predicting the performance of each component was constructed and calibrated with the acquired experimental data using ANSYS software. Experimental Investigation of the performance of the crosstie and fastening system when subjected to cyclic loading and wear/abrasion. Further optimization and calibration of the material model. Implementation of the HDPE crossties in elevated structure-bridge applications as well as assessment the track bridge interactions.
Secondary Supporters: Tangent Technologies and the Chicago Transit Authority
Ibrahim Lotfy, Maen Farhat and Mohsen Issa, Univeristy of Illinois at Chicago Primary Grant Support: NURail Center (U.S. DOT-RITA)
Problem Statement and Motivation •
• 4,000 3,500 3,000
STRESS, psi
2,500 2,000 1,500
10 F 40 F 73 F 100 F 125 F
1,000
500 0 0.00
0.01
0.02 0.03 0.04 STRAIN, in./in.
0.05
0.06
Key Achievements and Future Goals
Technical Approach Striving to assess the feasibility of implementing HDPE crossties in rail applications, this study examines its flexural behavior. I. Perform experimental testing as per AREMA specifications: • Investigate the flexural behavior, cracking and failure modes of HDPE Crossties under different conditions; center and rail seat bending. • Assess the effect of temperature changes on the flexural and mechanical properties of the HDPE crossties. II. Conduct a finite element analysis using ANSYS: • Construct a calibrated non-linear material model for use in subsequent analyses. • Develop a suitable modelling technique which portrays the actual behavior of the crosstie.
High Density Polyethylene (HDPE) is a green, recyclable, and environmental friendly material. It has structural and economical advantages which grant it a competitive edge among other alternatives in the rail market such as wooden and concrete crossties The implementation of the new recycled Plastic railroad crossties would improve the railroad industry public image as a green, sustainable industry. The recycled products are manufactured with plastic waste that otherwise would be landfilled which reduces the waste products and additionally eliminates any pollution or deforestation. Moreover, Recycled, HDPE crossties are light, workable, easy to transport and handle, can overcome the main issues facing other materials and can replace wooden crossties on a one-to-one basis without the need for special installation or heavy equipment.
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•
• • •
The HDPE crossties satisfied and surpassed the AREMA requirements for polymer composite crossties in terms of flexural strength and stiffness (MOE and MOR). An accurate material model capable of predicting the flexural performance of HDPE crossties was constructed and calibrated with the acquired experimental data using ANSYS finite element package. Experimental Investigation of the performance of the crosstie and fastening system when subjected to cyclic loading and wear/abrasion. Further optimization and calibration of the material model. Implementation of the HDPE crossties in elevated structure-bridge applications as well as assessment the track bridge interactions.
Secondary Supporters: Tangent Technologies and the Chicago Transit Authority
Aiman Shibli and Mohsen Issa, University of Illinois at Chicago
Problem Statement and Motivation 9 8 7 6 5 4 3 2 1 0
Shear Test:
#1 #2 #3 #4 #5
0
5
10 Tensile strain
15
Spc-1 [14 days curing] Spc-2 [14 days curing]
0.5
1
1.5
2
Strain
Ball Drop :
Accelerometer
PC Supporting pin
Supporting pin
Supporting pin
Strain Gauges
Strain Gauges
0.01
Sim - Gauge - Top Sim - Gauge - Bot Test - Gauge - Bot Test - Gauge - Top
Big Plate: 70mmX20mmX1mm Small Plate: 20mmX20mmX1mm Adhesive: 70mmX20mmX0.2mm Top Span: 35mm Bottom Span: 60mm
Supporting pin
Test - Gauge - Top Sim - Gauge Bot
0.006
Sim - Gauge Top
0.004 50
•
Test - Gauge - Bot
0.008
100
150
200
250
Strain
Strain
0.01 0.008 0.006 0.004 0.002 0 -0.002 0 -0.004 -0.006 -0.008 -0.01
•
Spc-3 [7 days curing]
0
20
Loading pins
Four Point Bending:
9 8 7 6 5 4 3 2 1 0
Stress [Mpa]
Tensile stress [MPa]
Tensile Test:
•
0.002 0 -0.002
Force [N]
0
0.002
-0.004
0.004
0.006
Time (sec)
Key Achievements and Future Goals
Technical Approach • • •
Fiber-reinforced polymer (FRP) composites are increasingly used in structural applications due to their advantageous material properties. However, structural FRP components are difficult to connect using the traditional joining methods such bolting and riveting due to the brittle fibrous and anisotropic nature of the materials. Many structural industries have seen the use of adhesive for joining load-bearing components as an excellent candidate for replacing the traditional joining due to their unique characteristics such: high strength, light weight, dimensional stability, high joint efficiency and ease of use. In order to utilize adhesives bonding in civil infrastructure applications, it is crucial to understand their behavior and strength and to be able to predict it for a given geometries and loads.
Characterize adhesive’s mechanical property under tensile and shear loadings, at low and high rates (static and dynamic). Build representative material model that can mimic their behavior and can be used in numerical models for computational studies. Validate material model experimentally and computationally at coupon level and sub-system level at quasi-static and dynamic loadings.
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Quasi-static and dynamic experiments were completed on structural adhesive at different loading modes: tension and shear. Material model has been created and validated at coupon level and subsystem level, under quasi-static and dynamic loadings. Comparison between experimental results and numerical results obtained from 3D finite element analysis showed very good correlation at different loading modes and rates. Future work, this study need to be implemented and investigated in real case application
Mustapha Ibrahim, Mohsen Issa, PhD, and Mustafa Al-Obaidi, Univeristy of Illinois at Chicago Primary Grant Support: Illinois Department of Transportation (IDOT)
Problem Statement and Motivation • •
Cement production account for more than 5% of CO2 emission worldwide. On average, each ton of cement produced from a cement plant accounts for 0.92 tons of CO2 emissions. Reducing this carbon emission requires a breakthrough technology that might take decades to be adopted by the cement industry. One of the low-cost successful methods that aided in developing a more sustainable production program was in adding pulverized limestone and other inorganic processing to cement, reducing the amount of clinker in its production. IDOT is making several changes to concrete mix designs by applying revisions to cement specification. These proposed revisions will enable the use of more limestone and inorganic processing additions (IPA) (sustainable materials) for concrete pavements, overlays, and bridge decks. A study was conducted to test the performance of concrete mixes batched with cement comprising of higher quantities of limestone and IPA.
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Key Achievements and Future Goals
Technical Approach • •
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The goal is to develop economical and practical concrete mixes that would provide sustainable and durable concrete pavements. Twenty-four concrete mixes with different cementitious combinations and aggregates were developed for this study. Three sources of cement were used. The mix combination of each cement source is shown below: • The program included testing the fresh and hardened strength and durability properties of concrete. • The fresh properties included measuring the slump, air content, unit weight, and setting time. The strength properties included testing the compressive and flexural strength of concrete. The durability properties included testing the Freeze and thaw resistance and rapid dynamic modulus of concrete, microscopic hardened entrained air, rapid chloride penetration resistance, salt ponding and chloride ion penetration, and water permeability.
• • •
•
•
The use of limestone and IPA in cement with quantities above the specified limits proved to have similar performance to conventional cement when mixed in concrete. The use of different cementitious materials (Fly Ash or Slag) improved the durability of concrete The success of this project prompted the IDOT to adopt the use of the new modified cement in replacement to the conventional cement. The amount of cement used in concrete batching was 375 lbs/yd3 which is the minimum cement content required by IDOT. As a result of this study, the amount of cement was increased from 375 lbs/yd3 to 400 lbs/yd3. Future development of concrete service life predictions and models to study the chloride ingress/ diffusion in concrete and its resistance to freeze and thaw.
Hossain Saboonchi, PhD Student and Didem Ozevin, Assistant Professor Department of Civil and Materials Engineering Primary Grant Support: UIC, Faculty Research Award Out of plane AE sensor (fn=50 kHz)
Problem Statement and Motivation
Out of plane AE sensor (fn=200 kHz)
In plane Inertia Switch (fn=150 Hz) Out of plane Inertia Switch (fn=100 Hz) Strain Sensors (120 Ω & 350 Ω)
Capacitance change
In plane AE sensor–gap change (fn=150 kHz)
SEM image of MEMS strain sensor
In plane AE sensor–area change (fn=100 kHz)
dC d dA dg Co A g
• Acoustic Emission is a highly sensitive Structural Health Monitoring method to monitor damage in aging structures. However, the sensitivity to environmental noise requires significant post-processing to differentiate the relevant data. • Single SHM method may not be sufficient for reliable damage detection and diagnostics. Multiple information collection simultaneously reduces the uncertainty.
SEM image of In plane AE sensor–gap change (fn=150 kHz)
Technical Approach • Multiple sensing elements are designed on the same device, including acoustic emission sensor to measure motions in out-of-plane and in-plane, strain and vibration to be used as inertia switch to activate AE collection. • The response of in-plane sensor to the out-of-plane motion is eliminated through novel differential mode approach. • The AE sensor is connected to on-chip inertia switch in order to collect AE data when the structure is highly stressed. The hypothesis is that the crack grows when the structure is loaded above a certain level.
• MEMS allow manufacturing multiple sensing mechanisms on the same device.
Key Achievements and Future Goals • The MEMS sensors are designed, modeled using COMSOL Multiphysics software and manufactured using MetalMUMPS process.
MEMS AE sensor
• The electrical and mechanical characterizations are completed. • The device will be tested in laboratory for detecting crack initiation and growth.
MEMS strain sensor
Didem Ozevin, Assistant Professor, Zahra Heidary PhD Student, Nadia Simek Undergraduate Student Department of Civil and Materials Engineering Primary Grant Support: NSF
Problem Statement and Motivation
single point leak localization
• The buried and on-ground pipelines develop damage due to temporal variables such as corrosion and creep or instantaneous threats such as earthquake and impact.
New Approach with Particular Geometry Sensor Design
• The detection of leaking at oil, water or natural gas pipelines before reaching structural instability can increase the public safety and prevent environmental pollution. • Passive nature of Acoustic Emission implemented for real time leak detection.
method
can
be
• The challenge is that the sensor sensitivity and wave attenuation prevent a reasonable sensor spacing for pipeline networks.
Technical Approach • The numerical models are linked with experimental studies to understand the reliable leak detection range and sensor spacing. The waveform properties of leaks due to different operational conditions can be identified experimentally. • Shear type Acoustic Emission sensor increases the sensor spacing range due to less attenuative characteristics of longitudinal waves. • Highly efficient numerical formulation is developed to study wave propagation in pipes due to non-axisymmetric loading. • Wave characteristics due to different leak rates for different frequencies are investigated.
Key Achievements and Future Goals • The AE characteristics due to varying pipe pressure, leak size and earth pressure are identified. Numerical attenuation curves are driven. • The AE sensor is designed with a particular geometry, modeled numerically and manufactured. • The developed transducer and the numerical model will be tested in a field condition.
Comparison of 2D efficient model with conventional 3D models
Didem Ozevin, Assistant Professor and Zeynab Abbasi PhD Student Department of Civil and Materials Engineering Primary Grant Support: TRB IDEA and NSF
Problem Statement and Motivation Complex loading case
Wave change with stress
Laboratory calibration for biaxial loading for existing equation as
Technical Approach • The research objective of this proposal is to understand the interaction between nonlinear ultrasonic characteristics and stress state of complex loaded critical structural components in order to measure the stress state at a given cross section. • The goal is to quantify the normal stresses and shear stress at a given cross section, which will be achieved through testing a set of frequencies to create Rayleigh waves with varying depth of penetration. • The equation in the literature will be modified to introduce the effect of shear stress on nonlinear ultrasonic measurement as
Dv = K1s 1 + K 2s 2 + K3s 12 vo
• Understanding the risk for a built structural element requires knowledge of the cumulative stress state in order to estimate the remaining strength such as residual stress and excessive loading condition. • A reliable damage prognostic approach should have a welldefined damage accumulation function. • The quantification of the cumulative stress state for a built element is needed for preventing unexpected failures at highrisk structural elements. • Currently, there is no nondestructive testing method to find stress tensor including normal and shear stresses.
Key Achievements and Future Goals • Multi-scale bridge model is built to estimate stresses at a 3/8 inch thick gusset plate. • An ultrasonic measurement device to quantify the stress at three directions is built.
• The measurements from laboratory scale plate will be conducted and theoretical equations will be modified to include the shear stress.
Mohsen A. Issa, Ph.D., P.E., S.E., FACI, Department of Civil and Materials Engineering Primary Grant Support: Illinois Department of Transportation
Problem Statement and Motivation •
The interstate highway system is approaching its service life and urban congestion is increasing. Anticipated future costs of repair/reconstruction of the nation’s infrastructures are huge.
•
Utilization of innovative full-depth deck panel system (high performance, durable, ease and speed of construction, cost-saving, aesthetic, minimal noise, and no interference with the traffic flow) leads to substantial reductions in the costs of repair and new construction projects.
•
The concerns about the performance of the components of the system and its constructability require systematic optimization to achieve high performance and fast construction.
Key Achievements and Future Goals
Technical Approach •
All of the full-depth system major components (deck panels configurations, transverse joints, post-tensioning levels, shear connectors, overlay system, and materials) were tested and optimized based on consecutive studies included large scale specimens and prototypes.
• • •
•
Nonlinear finite element models were created to optimize the components and support the experimental testing.
•
Based on the findings, a full-scale prototype bridge full depth deck panel system was designed, fabricated, and tested with and without overlay simulating AASHTO HS-20 truck loading, overload, and ultimate load .
•
Complete innovative full-depth deck panel system with clear information about its constructability and details and performance of its components was developed . The system is utilized in many new and repair bridge projects implementing the recommendations of this study. Current and future research are focused onto generalizing the fulldepth concept to develop totally prefabricated superstructure system (bridge deck and beams). The developed full-depth system as well as the LMC overlay system will be utilized in the coming New Mississippi River Bridge Project (the widest stay-cable bridge in the world).
Ben O’Connor, Department of Civil and Materials Engineering, University of Illinois at Chicago Kirk LaGory and John Hayse, Argonne National Laboratory Primary grant agency: Western Area Power Administration Developing models to assess hydropower impacts to downstream fish communities of interest
Problem Statement and Motivation •
•
Rainbow Trout
(study site is Green River, downstream of Flaming Gorge Dam, Utah) Brown Trout
•
•
Development of geomorphic change detection analyses to assess changes to channel morphology and habitat conditions Develop 2-dimensional hydraulic models to simulate environmental flow regimes Integrate hydraulic model with individual-based models (IBMs) to predict fish behavior
Analysis of channel geomorphic change following 2011 flood flows in critical trout reach
Alterations to downstream flows
Key Achievements and Future Goals
Technical Approach •
Flow releases from large hydropower facilities have downstream impacts to aquatic ecology Develop quantitative hydraulic and sediment transport models to assess flow release impacts to habitat and flow regimes affecting fish communities
• • •
Channel bathymetric and hydraulic surveys completed in 2012 Hydraulic and IBM models being developed Future goals include evaluating hydropower release scenarios and unsteady flow conditions relating to ramping rates of the hydroelectric facilities
Ben O’Connor, Department of Civil and Materials Engineering, University of Illinois at Chicago Yuki Hamada, Argonne National Laboratory Primary grant agency: Department of Energy
Problem Statement and Motivation •
•
Extracting stream channel properties from spectral data to evaluate impacts to ephemeral streams in arid ecosystems being considered for utility-scale solar energy development (study site near Blythe, California)
Key Achievements and Future Goals
Technical Approach •
•
•
Develop extraction algorithms for high-resolution stereo-imagery that can identify channel networks and quantify meaningful channel geometry properties Use hydrologic simulations to assess the transport of water through ephemeral stream networks Combine hydrologic simulations with spectral indices of vegetation and soil characteristics to evaluate the ecological significance of certain stream channel reaches
Physical and ecological processes of ephemeral streams in arid environments is difficult to quantify because of the episodic nature of hydrologic events. Renewable energy development has the potential for large-scale land use changes and alterations to stream networks
Multispectral Image Vegetation Index PCA Layer Stack & Spatial Heterogeneity Analysis Channel Map Stream Line Map
• • •
Developed channel network extraction algorithm Stereo-imagery collected in January 2014 Developing digital surface model from stereo-imagery to extract channel geometry features
Input Image
Channel Map
Krishna R. Reddy, Department of Civil & Materials Engineering Primary Grant Support: National Science Foundation
Problem Statement and Motivation •
More than 500,000 contaminated sites exist in the U.S. that require urgent remediation to protect public health and the environment
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Existing technologies are ineffective or expensive for the remediation of mixed contamination (any combination of toxic organic chemicals, heavy metals, and radionuclides) in heterogeneous/low permeability subsurface environments
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Innovative and effective new technologies are urgently needed
Key Achievements and Future Goals
Technical Approach •
Chemical oxidation can destroy organic contaminants, while electrokinetic remediation can remove heavy metals
•
Integration of chemical oxidation and electrokinetic remediation is proposed to accomplish simultaneous: • Electroosmotic delivery of the oxidant into homogeneous and heterogeneous soils to destroy organic contaminants • Removal of heavy metals by electromigration and electroosomosis processes
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Fundamental processes and field implementation considerations are being investigated through bench-scale experiments, mathematical modeling, and field pilot-scale testing
•
Bench-scale experiments revealed that: • Oxidants such as hydrogen peroxide can be introduced into clay soils effectively based on electroosomosis process. Native iron in soils can be utilized as catalyst in Fenton-like reactions. Organic compounds such as PAHs can be destroyed. • Heavy metals such as mercury and nickel can electromigrate towards the electrode wells and then be removed. • Electrical energy consumption is low
•
On-going research evaluating field contaminated soils, optimization of the process variables, mathematical modeling, and planning of field pilot-scale test.
Krishna R. Reddy, Department of Civil and Materials Engineering Primary Grant Support: NSF, EREF, CReeD & Veolia Environment
Problem Statement and Motivation •
In conventional “dry tomb” landfills, waste biodegradation is very slow because of the lack of adequate moisture. These landfills require longterm monitoring for any potential environmental problems (regarding the water and air pollution).
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The leachate re-injection or addition of selected liquids to landfill waste (bioreactor) has potential to accelerate waste decomposition and settlement, but will affect the waste properties and slope stability.
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Urgent need exists to understand the moisture distribution in the waste and its effects on waste biodegradation and properties as well as geotechnical stability of landfills.
Key Achievements and Future Goals
Technical Approach •
Monitoring several bioreactors to monitor moisture content (with geophysics), biogas and leachate production and quality, waste degradation and properties, and waste settlement.
•
Developing a mathematical model for: • Understanding the spatial and temporal variations of moisture distribution and landfill settlement • Incorporating change in waste properties caused by decomposition with respect to time • Understanding the influence of leachate recirculation on landfill settlement and slope stability • Optimizing leachate recirculation system designs
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Field monitoring at bioreactor landfills is in progress. Studies conducted to date show that dynamic moisture variations within the waste mass during leachate recirculation can be characterized with geophysical methods (electrical resistivity tomography).
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Coupled flow and mechanical modeling is in progress for different bioreactor landfill conditions. Preliminary results show that the coupled flow and mechanical modeling can predict both waste moisture and settlement with time under different operational conditions.
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Field monitoring and modeling results will be utilized to develop design and monitoring guidelines for bioreactor landfills.
Krishna Reddy & Kevin Richards, Department of Civil and Materials Engineering Primary Grant Support: National Science Foundation
Problem Statement and Motivation p'-Qcrit
Qcrit (cm3/sec)
1.5 1.0
y = 0.027x + 0.845
•
Piping causes approximately 46% of all dam failures, with the backwards erosion mode of piping in perhaps 31% of all these piping cases
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Current methods for evaluation of backwards erosion piping have not been successful in preventing or assessing piping in unfiltered dams, which results in billions of dollars in unnecessary damages and repairs each year.
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A laboratory investigation of the constitutive behavior of pipe initiation is necessary to define key parameters that influence piping potential and to allow formulation of predictive tools and develop remediation strategies.
0.5 0.0 -5
1.27 cm opening 0.52 cm opening
0
5
10
15
p' (N/cm2)
Key Achievements and Future Goals
Technical Approach •
Previous investigations into piping have focused on pipe progression. Our focus is on pipe initiation, which should yield a more sensitive tool for the prediction of the critical hydraulic conditions necessary to initiate piping.
•
•
Previous investigators have found a correlation between confining stress conditions and critical piping parameters. Our work is addressing this phenomenon in more detail.
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Research includes conducting bench-scale experiments to (1) determine the critical hydraulic gradient and the critical discharge coefficient of different granular soils subjected to variable confining stresses in a true-triaxial load cell, and (2) assessing the influence seepage direction and the rate of change in hydraulic loading conditions has on the critical hydraulic gradient and critical discharge coefficient.
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•
Different soil types have been characterized and are being used in the experiments Preliminary results have found a relationship between the confining stresses and critical piping parameters when soils are in a nonbuoyant condition The geometry of the exit also plays a large role in pipe initiation due to the convergence of flow lines at the exit point and increased gradients due to confinement. This explains the high incidence of piping failures where convergence effects are produced around buried structures. The influence of seepage direction and rate of change of hydraulic loading are currently being investigated.
Krishna Reddy & Amid Khodadoust, Department of Civil and Materials Engineering Primary Grant Support: National Science Foundation
Problem Statement and Motivation •
Nanoscale zerovalent iron (nZVI) particles have the potential to be superior to iron filings, both in terms of initial rates of reduction and total moles of contaminants reduced per mole of iron.
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Instead of waiting for the contaminants to pass through the permeable reactive barriers, the nZVI particles can be injected into the contaminated source zones for rapid and effective detoxification of the contaminants.
•
The delivery of nZVI particles into the contaminated zones uniformly and in required amounts in a controlled manner is essential for effective remediation.
Fe3O4 70nm
Fe0
Key Achievements and Future Goals
Technical Approach •
Our hypotheses are that: (1) as a result of aggregation, nZVI particles can be transported only to limited distances in subsurface; and (2) enhancement strategies such as use of dispersants and pressurized system have potential to enhance transport of nZVI particles in subsurface.
• • •
•
Research scope includes conducting (1) bench-scale column experiments to determine transport of nZVI particles in different gradation soils without and with enhancement strategies, and (2) bench-scale tank experiments to determine transport of nZVI particles in homogeneous and heterogeneous soils under the optimal conditions determined from the column experiments. Preliminary mathematical modeling will be performed to predict the transport of nZVI particles in porous media under laboratory and simulated field conditions.
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Different soil types and commercial nZVI particles are being characterized and used for the experiments Enhanced treatments are being achieved through the use of novel dispersants, pressurized system, and the simultaneous use of dispersant-pressurized systems. The commercial nZVI particles possess magnetic properties; therefore, a real-time transport of the nZVI particles in porous media is being monitored using an electromagnetic susceptibility sensor system. Experiments are being conducted to evaluate the effects of soil heterogeneities on the transport of nZVI particles. The reactivity of nZVI particles is being quantified before and after transport in contaminated soils.
Krishna R. Reddy, PhD, and Hanumanth S. Kulkarni (PhD Candidate), CME, UIC Primary Grant Support: CReeD, VEOLIA, and NSF Leachate injection (horizontal trenches) Biogas collecting and reclaiming
Leachate injection (wells) Leachates storage
Problem Statement and Motivation •
Leachate collecting
Biogas collecting
• •
•
Bioreactor landfill technology has been introduced recently which involves recirculation of generated leachate back into the landfill with the help of different leachate recirculation systems (LRS) and therefore reduce the time taken for the MSW to biodegrade within 15-30 years compared to conventional landfill that takes about 50-100 years Leachate introduction in a bioreactor landfill increase moisture and pore pressures and therefore physical stability has to be ensured Hydraulic properties (saturated hydraulic conductivity and unsaturated hydraulic parameters), type of LRS employed, mode of leachate recirculation, geotechnical properties of MSW with respect to biodegradation affect the moisture distribution in a bioreactor landfill The main objective of this study is to develop design guidelines to optimize the LRS achieving uniform moisture distribution throughout the landfill, generating an optimal environment for the waste to degrade.
Key Achievements and Future Goals
Technical Approach •
Moisture increase in the landfill helps distribute the nutrients and microbes that are responsible for the MSW biodegradation
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Moisture distribution in an unsaturated municipal solid waste (MSW) is being investigated by two-phase flow theory
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Two-phase flow consider the flow of recirculated leachate and generated landfill gas within the pores of MSW solids
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Flow of leachate and landfill gas are modeled by Darcy’s Law, and the unsaturated hydraulic conductivity of MSW for leachate and landfill gas are modeled by van Genuchten fitting function
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The developed model was validated based on few field observations, laboratory studies, and previous mathematical modeling results documented in literature.
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•
MSW has to be considered as heterogeneous and anisotropic over homogeneous and isotropic to simulate field condition Intermittent leachate recirculation in bioreactor landfill proves better than the continuous recirculation to generate an optimal environment in a landfill without producing excess pore water pressure Proper unsaturated hydraulic properties of MSW has to be considered in the design of LRS in a bioreactor landfill Spatial variation of hydraulic properties affect the moisture distribution in the bioreactor landfill and therefore, probabilistic approach has to be followed in designing the LRS Development of design charts and guidelines to optimize these LRS are in progress and the coupled flow-mechanical analysis of the moisture distribution will be carried out in future.
Prof. Krishna Reddy, Ph.D., P.E. (Principal Investigator), Sara Dastgheibi (M.S. Student), CME, UIC Prof. Krishna Pagilla, Ph.D., P.E. (Co-Principal Investigator), Giridhar Prabhukumar (Ph.D. Student), CAEE, IIT Primary Grant Support: US EPA, Grant ID GL-00E00526
Problem Statement and Motivation • •
• • •
Key Achievements and Future Goals
Technical Approach • •
•
Correlate the urban stormwater runoff quality to beach water quality monitoring parameters. Quantify contaminant attenuation and/or degradation capacity and hydraulic efficiency of different filter media materials individually and in sequence simulating layered filter design under different simulated urban stormwater runoff conditions, and Demonstrate a near full-scale design to determine flow rate/volume treated, and contaminant removal at one of Chicago’s public beaches.
The potential for beach water contamination due to stormwater runoff in urban settings (e.g., Chicago) is a significant concern. Pollutants found in urban runoff include microbial contamination, nutrients, toxic metals, oil & grease and other organic contaminants. Of these, microbial contamination is the main reason for beach closures in the Great Lakes region and the other contaminants present in the stormwater encourage their growth. Current best management practices (BMPs) are not feasible in urban setting and also to handle a variety of contaminants present in runoff. Media based filtration can be an effective way to treat urban runoff water without the risk of contamination of ground water, which is a concern with BMPs such as bioretention/infiltration systems. There are several natural and synthetic media choices that are known to remove a particular type of pollutant. However, it is a challenge to design a media based filtration system that can effectively remove a wide range of pollutants.
•
Currently, we are investigating the performance of different types of materials such as perlite, zeolite, anthracite, calcite, iron filings, sand, iron oxide coated sand (IOCS) and biochar, as possible media for our filter system. • Determine geoenvironmental properties of filter media. • Determine maximum infiltration rate and maximum hydraulic retention time of filter media. • Quantify contaminant removal and degradation of filter media by batch experiments. • Quantify contaminant removal and degradation of filter media by column experiments. • Select combinations of different filter media and optimize filter media based on their individual physiochemical and contaminant removal characteristics.
Development of Biochar-amended Landfill Cover for Landfill Gas Mitigation Krishna Reddy & Poupak Yaghoubi, Department of Civil and Materials Engineering
Problem Statement and Motivation •
Column 2: 20 % biochar amendment
• • • •
Column 1: Soil only
Fractional Oxidation of CH4 (%)
25 Column 1
Column 2
20
•
15 10
5 0
0.038
0.041
0.049
Landfilling is the most dominant solid waste management option in the world Landfill gas from MSW landfills consists mainly of CH4 and CO2 Methane greenhouse effect is 21 times more powerful than carbon dioxide The natural CH4 oxidation efficiency of landfill cover systems is not efficient , only 15% of the generated CH4 is removed from conventional landfill cover systems With its porous structure and high surface area, biochar, the carbon-rich product of biomass pyrolysis, facilitates the oxidation process by enlarging the oxidation layer of landfill covers The objectives of this study are to investigate the behaviors of biochar on adsorption, microbial oxidation and the effect of its amendment to the landfill cover soil on the landfill gas mitigation performance
CH4 Influx (ml/cm2 -min)
Key Achievements and Future Goals
Technical Approach • • • •
• • •
To study adsorption and transport properties of methane and oxygen To investigate the effects of biochar amendment on microbial oxidation within landfill cover To investigate the interaction between adsorption and oxidation for methane mitigation To test the adaptability of biochar amended landfill cover to variation of methane concentration, and environmental conditions such as moisture content and temperature Both Batch and Column test were conducted on adsorption and microbial oxidation of methane To evaluate the potential of mitigating CH4 emissions from landfill covers amended with biochar, experimental column testing in laboratory were conducted Distribution of methane along the length of the columns (one as a control with soil only and one with soil amended with 20% of biochar (w/w)) were studied
• • • • • •
The batch testing results showed that biochar has an adsorption capacity only 2 times as large as that of soil at 35 ˚C to methane but 10 times at 22 ˚C Adsorption of CH4 and CO2 onto biochar is exothermic reaction Adsorption capacity decreases as temperature increase On Microbial oxidation the concentration distribution along the depth suggested that reactions were taking place in top part of more than 30 cm for column 2 and 10 cm for column 1 The oxidation efficiency of CH4 with biochar amendment was up to 19.2 times that of column with soil only Biochar amended landfill cover is mostly suitable and promising for small or old abandoned landfills where the gas collection is not required and gas to energy project is not applicable
Eduard Karpov, CME Primary Grant Support: National Science Foundation
Problem Statement and Motivation • •
• • Hot electron mechanism of electrolyte-free chemical to electrical energy conversion; Karpov et al., APL 94, 214101
Key Achievements and Future Goals
Technical Approach • •
Electric charge separation and the resultant electromotive force can be achieved in electrically continuous metal-semiconductor catalytic structures with nanometer thickness metallization (diagram above) Metal nanofilm thickness must be smaller than the hot electron mean free path that is 10-50 nm for most catalytic metals Laboratory system setup for hot electron current detection: (1) vacuum/gas handling components (2) mass spectrometer (3) signal conditioning unit (4) multichannel temperature controller (5) analytical chamber (6) main flange for sample mounting (7) high precision V/A source
Traditional fuel cell technologies based on ground-state electrochemistry suffer from slow-rate ionic diffusion, spurious electronic conduction in electrolytes and electrolyte degradation At the same time, synergistic catalytic effects observed in composite catalysts, in particular, in photocatalysts with a nanodispersed metal phase is surprising. Evidence exists that it owes to an exchange of inequilibrium charge carriers (hot electrons) at the metal/nonmetal support interface Reaction induced hot electron flow in a class of electrically continuous metal-semiconductor catalytic nanostructures provide a hope for “electrolyte-free chemical to electrical energy conversion” Hot electron currents detected in metal-semiconductor nanostructures also provide a valuable in-situ analytical tool to study basic physical mechanisms of heterogeneous catalysis
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• •
Studies of Pd/SiC, Pd/GaP and Pt/GaP prototypes revealed the hot electron component to comprise 60-85% of the total current induced by the H2+1/2O2 = H2O surface reaction, and the remaining fraction belongs to the usual thermal currents Reliable techniques to separate the hot electron and thermal currents have been developed Electron yield of a potential electrical generator was 0.20 for the SiCand 0.11 for GaP-based prototypes, implying a big promise for this electrolyte-free chemical-electrical energy conversion approach The hot electron current was also demonstrated for identification of distinct modes of the surface reaction Higher efficiency material systems operating at room temperature are currently underway