The research of the effects of grain size, oxidizers, and catalysts on band gap energy of gelam-wood carbon has been conducted in which the carbons were produced from gelam-wood pyrolysis in high temperatures. The instrumentations used in this study were UV-Vis, FTIR spectrophotometer, and SEM. SEM and FTIR were used to characterize the morphology and the functionality of the carbon surface. UV-Vis spectrograms showed that the electronic property of carbon such as band gap was affected when grain size and surface area were changed. The increase of the functional groups in carbon occurred as the surface area of the carbon was increased. Band gap energy of crystalline carbon became much lower along with the increase in grain size due to the effects of bands-broadening. FTIR spectrograms showed that the carbon contained of hydroxyl and carboxylic groups. The hydroxyls were derived from steam-oxidized carbon that was provided narrower in the interlayer distance and lower-set band gap energy. Carboxylic groups were derived from acid nitric oxidation causing flat layer to become curved. The layers were wider and the band energy was higher. The main factor that affects the electronic structure of metal oxide in carbon/metal oxide composites was atomic alignments. The band gap energy increased along with the increase of the asymmetry alignments in metal oxide.

The application of reduced carbon anode layer and LiFePO4 cathode was conducted in laboratory-scale battery. Both electrodes were fabricated into lithium - ion battery with LiCl electrolyte in both gel and liquid based. The carbon was prepared by using Hummer method and solvent sonification to exfoliate the carbon layer from biocarbon. The battery performance tests were carried out in potentiostat for Cyclic Voltammetry (CV) and galvanostatic measurements. The highest current of CV measurement can be obtained in the battery with reduced carbon layer anode and 20% of liquid electrolyte. It was calculated that the same battery produced the highest energy and power. Current - Voltage profile is relatively stable in CV of batteries with 40% electrolytes in both gel and liquid media. All batteries have two peaks in both anodic and cathodic. The reduction peaks show in around 0.5 and 1.5 volts. The cathodics show in around –0.5 and –1.5 volts. The best power and energy values are given by battery with rCNSO anode and 20% liquid electrolyte. Galvanostatic profiles show that the 40% electrolytes in the batteries produces a slower discharging process. It was revealed that applying anode of layer reduced biocarbon as the battery electrode caused the discharging to run faster. The highest slope value of the galvanostatic curve can be found in the battery with the electrode of oxidized starting material and 40% of gel electrolyte, while the lowest can be found in 20% gel electrolyte with the same electrode.

The shifting trend of conventional to the electric drivetrain in automotive industries makes batteries become the most favorable energy storage. There are three types of battery cells that are commonly used for electric vehicles i.e., cylindrical cells, pouch cells, and prismatic cells. The use of active material such as lithium-ion in the battery of electric vehicles could bring some issues related to the safety field. For that reason, comprehensive research on battery failure analysis needs to be conducted. This paper reviews the recent progress of the use of battery cells in electric vehicles and some challenges which must be considered to assure their safety. There are a lot of studies on battery failure analysis, which mainly focuses on the appearance of a short circuit as the main cause of the thermal runaway event. Several proposals on predicting short circuits in the battery due to various loading are comprehensively discussed. Those research results can be considered to establish regulations in designing battery protectors.

This article delivered an innovative idea of a magnetorheological (MR) damper for secondary suspension of train bogie. The valve inside MR damper adopted meandering of both fluid flow and magnetic flux for improving magnetization area. In this work, the design and working principle of the MR valve were presented including a mathematical model to predict the pressure drop. In the early stage, the finite element method magnetics software (FEMM) simulation could predict the magnetic flux density across the passages. Based on the amount of magnetic flux, the corresponding shear yield stress could be determined from its basic physical properties. The mathematical model covered pressure drop prediction for both off-state and on-state. The FEMM simulation results showed that the meandering flow and serpentine flux design could improve the effective area of magnetization. Consequently, the pressure drop of the valve could have wider ranges and achieve a high value of pressure differences. This result could be potentially improving the performance of the damping forces of the lateral damper in a bogie train.

Palembang City in August 2018 was the first city in Indonesia which operated a mass transit of Light Rail Transit (LRT). LRT in Palembang City has a length of 23 km and 13 stations that stretch from the Airport station to the DJKA station. In its first year of operation, it was noted that the number of passengers using LRT was still very small, some efforts were needed to increase the number of LRT passengers. This study aimed to increase the number of LRT passengers by analyzing the development of the feeder line, the potential for increasing the number of passengers, and the infrastructure needs to support LRT operations in Palembang. The results show that four stations have the potential to develop feeder lanes, namely Asrama Haji station, RSUD station, Garuda Dempo station, and Polresta station, with the increased total number of potential passengers of 1460 passengers/day. The supporting infrastructure needed to support movement using LRT consists of a park and ride facilities, pedestrian bridges, the construction and repair of pedestrian facilities, and drop-off and pick-up facilities.