Electrospun nanofiber from various source of expanded polystyrene (EPS) waste

This paper wrote by an international group of scientist, including Dr. Eng Muhammah Miftahul Munir (FMIPA ITB) reported on the fabrication of nanofibrous membranes from various sources of expanded polystyrene (EPS) waste using electrospinning technique and their application as air filter media. The filter membranes were made from four EPS waste sources, i.e. food packaging, EPS craft, instant noodle cup, and electronic packaging.

The properties of the membranes fabricated from those sources were compared to obtain the best EPS waste source for air filter application. To make the precursor solutions, those samples were dissolved in d-limonene:DMF . The solid EPS density, solution viscosity, and surface tension were measured. The fiber diameter and morphology of nanofibers were characterized by scanning electron microscopy (SEM) for each EPS variation.

The fabricated membrane properties (crystallinity, wettability, and mechanical strength) and filtration properties (pressure drop, PM2.5 filtration efficiency, and quality factor) were fully characterized and analyzed. Homogeneous fiber diameter with various morphologies (beaded, wrinkled, and smooth fiber) were obtained from all samples with hydrophobic to super-hydrophobic surface.

Waste Management Volume 103, Pages 76 – 86, 15 February 2020

g TRAVEL BEHAVIOUR

Also, the EPS solid density affected the solution viscosity with certain expression, which then affected the fabricated membrane packing density, porosity, and mechanical properties. Overall, the experimental results showed that all EPS nanofiber filters had great potential as an air filter media. The EPS filter made from food packaging waste with the solution concentration of 15 wt% exhibited the highest efficiency and quality factor .*

To compete or not compete

Exploring the relationships between motorcycle-based ride-sourcing, motorcycle taxis, and public transport in the Jakarta metropolitan area

Transportation Volume 47, Issue 5, Pages 2367 –2389, 1 October 2020

In the last decade, the emergence of ride-sourcing services has transformed personal trip behavior. In the context of Indonesia, ride-sourcing services have evolved into two modes of transport: motorcycle-based and car-based. The presence of such services has strongly impacted consumers’ choices of travel mode. However, the main question is whether the ride-sourcing service is a complement or a substitute for the existing public transport and conventional taxis.

Prawira F. Belgiawan Ph.D., scientist with Business Strategy and Marketing Interest Group ITB is co-author of a study to explore the relationships between motorcycle-based ride-sourcing, motorcycle taxis, and public transport in the Jakarta metropolitan area.

TIMES CITED 37 JOURNAL IMPACT FACTOR 5.192

The result shows that motorcycle-based ride-sourcing works as a complementary mode for the TransJakarta bus and Jakarta commuter train, but as a competitor with the motorcycle taxis. Contrarily, motorcycle taxis supported the existence of motorcycle-based ridesourcing. The study also found that individuals use motorcycle taxis as feeders to transit stops.*

Experimental analysis to design optimum phase type and salinity gradient of Alkaline Surfactant Polymer flooding at low saline reservoir

This paper presents the experimental analysis to find the optimum alkaline-surfactantpolymer (ASP) formula and the effects of salinity gradient suitable for oil reservoirs with low salinity formation water. It has been challenging to obtain high oil recovery when the reservoir salinity is lower than the injection salinity of ASP formulation.

A group of researchers, including Prof. Asep Kurnia Permadi, Ph.D. (Reservoir Engineering Research Group of ITB) carried out phase behavior tests for 28 experiments with 22 kinds of surfactant and subsequent coreflooding for the optimum formula with pre-designed salinity gradient profiling for preflush, ASP slug, and polymer drive. The optimum ASP formula from the phase behavior study, i.e., 0.5 wt% Linear alkylbenzene sulfonate (LAS), 2 wt% Diethylene glycol butyl ether (DGBE), and 1 wt% Na2CO3, results in the optimum salinity of 2.8 wt% NaCl with 10 cc/cc solubilization ratio, and the middle phase type III microemulsion occurs in the range of 2.5–3.4 wt% NaCl.

The oil recovery implementing this formula and negative salinity gradient, i.e. Winsor type II-III-I for coreflooding experiments are about 75.8% which is better than the other salinity gradients such as Winsor type I-II-I and I-III-I. Excluding high saline preflush, the salinity gradient consisted of Winsor type I-II-I and Winsor type I-III-I are able to recover the desirable amount of oil. The results could be applicable on designing the optimal ASP flooding at low salinity formation considering the formulation of surfactants and co-solvents, and the effects of salinity gradients.*

The largest obstacles in the utilization of municipal solid waste (MSW) as solid fuel in developing countries such as Indonesia are its high water content, irregular size and shape, and difficulty-to-sort due to the mix of plastic and organic waste. Based on literature study, wet torrefaction could be an appropriate pre-treatment process for mixed MSW because it requires no initial drying and mixed organic-plastic MSW can be processed without initial sorting.

In this research by a group of scientist including Dr. Eng. Pandji Prawisudha (Energy Conversion Research Group of ITB), experiments were conducted to investigate the effect of wet torrefaction on increasing the fuel properties of mixed MSW. Based on field survey, the composition of the analyzed sample was: leaf litter (34.67%), food waste (23.33%), vegetable waste (14.33%), fruit waste (11.00%), and non-recycled plastic (16.67%).

The experiments were conducted in a 2.5-L stirring reactor temperature variation (150, 175, 200 and 225 °C) with several holding times and solid loads. The result showed that wet torrefaction at a temperature of 200 °C with holding time of 30 min and solid load of 1:2.5 was the optimum condition, producing solid product with uniform physical shape, small particles and homogeneous particle size distribution, HHV of 33.01 MJ/kg and energy yield of 89%. The wet torrefaction process is not only suitable to convert the mixed MSW into renewable high energy density solid fuel, but it can also be used to produce separated organic product that can be used as solid fuel and plastic product that can be prepared for other treatments, such as pyrolysis to produce liquid fuel or recycling.*

Journal of Petroleum Science and Engineering Volume 173, Pages 1005 – 1019, 1 February 2019

Waste Management

Volume 95, Pages 1 – 9, 15 July 2019