Vol. 56 No. 1 (2024)

Back Matter

Microbial fuel cells (MFCs) can potentially be used to overcome issues with battery powered light buoys and their frequent maintenance. In this study, a phototrophic sediment microbial fuel cell (PSMFC) was chosen, as the microalgae provide oxygen to be reduced on the cathode and to release the necessary nutrients for the bacteria on the anode. To achieve this, we studied the effect of illumination, the period of the illumination, and the distance between 9-cm2 stainless steel mesh electrodes on the performance of the MFC. The illuminated cells were able to produce higher OCP (max. 205.2 mV)…

In this study, a comprehensive evaluation was conducted of the condition and performance of a concrete arch-type bridge located in close proximity to a fault. Utilizing the LRFR capacity assessment method and seismic performance analysis through the NLTHA process based on the PBSD concept, finite element modeling (FEM) was employed with a focus on construction stage analysis and model updating for calibration to site conditions. The assessment encompassed the determination of the rating factor for structural elements under service and ultimate limit state loading. Performance analysis under…

The performance of carbon fiber reinforced polymer (CFRP) composite materials under quasi-static and high strain rate loading can be predicted with a high level of accuracy using the non-linear finite element analysis (FEA) method. Experimental validation tests under uniaxial tensile loading have shown a good correlation with FEA predictions for thermoset polymer composites, using commercially available epoxy resin MTM710 with carbon fiber reinforcement and for comparative tests on DP600 steel and aluminum alloys (AC170 and 5754 series). The physical and numerical results comparison of…

This study investigated the correlation between fault kinematics, surficial displacement, and surface rupture geometry patterns between earthquake cycles using particle image velocimetry (PIV) analysis of an analogue sandbox modeling that mimics InSAR observations. The research explored various fault systems, including reverse, normal, and strike-slip faults, through controlled sandbox experiments. The fault surface rupture zone manifests itself due to strain accumulation between two mobile blocks. The displacement magnitude is most pronounced on the surface and is absorbed by the section…

Today, facing difficult environmental and sustainability questions, the palm oil industry is an important force in global trade and development. As a transformative solution to these problems, this review assesses the implementation of circular economy (CE) strategies. CE principles promote the transformation of waste into value through recycling, upcycling and other low-carbon innovation applications. This review estimates the capability of palm-based biomass, including palm oil mill effluent (POME) and refinery wastes. It evaluates how different technologies such as gasification are used to…

This research investigated the performance of hematite-gamma alumina (Fe2O3/γ-Al2O3) catalyst in biodiesel production from palm oil. A full factorial experimental design was utilized to analyze the effect of hematite content, catalyst loading, and methanol-to-oil ratio on catalyst performance. From the experiment, biodiesel in the range of 73.6 to 87.6% FAME content was obtained. It was concluded that the catalyst composition, the methanol-to-oil ratio, and the catalyst loading have a significant effect on the FAME content of the biodiesel. Hematite has strong affinity for fatty acids, so a…

Corn is one of the primary carbohydrate-rich food commodities in Southeast Asian countries, among which Indonesia. Corn production is highly dependent on the health of the corn plant. Infected plants will decrease corn plant productivity. Usually, corn farmers use conventional methods to control diseases in corn plants. Still, these methods are not effective and efficient because they require a long time and a lot of human labor. Deep learning-based plant disease detection has recently been used for early disease detection in agriculture. In this work, we used convolutional neural network…

Oil sludge exhibits a compositional similarity to bitumen, a pivotal constituent in asphalt concrete mixtures. This similarity underscores the potential applicability of oil waste in the production of asphalt concrete, serving not only as an organic binder to fortify indigenous soils but also as a binding agent for the fabrication of organomineral mixtures. The incorporation of oil sludge in road construction endeavors holds promise for the conservation of natural resources, the amelioration of the environmental landscape, and a concurrent reduction in the cost of construction materials. The…

This study presents the application of an improved self-organizing migration algorithm (ISOMA) for minimizing the total electricity production expenditure (TEPE) and maximizing the total electricity sale profit (TPRF) for hydrothermal power systems (HTPS) without and with renewable energies. Two power system configurations were employed to test the real efficiency of ISOMA while dealing with two objective functions. In the first configuration, there was one thermal power plant and one hydropower plant, while in the second configuration, wind and solar energy were both connected to the first…

Pillars are key structural components in coal mining. The safety requirements of underground coal mines are non-negotiable. Accurately classifying the areas of pillar stability helps ensure safety in coal mines. This study aimed to classify new pillar stability categories and their stability areas. The multiclass support vector machine (SVM) method was implemented with two types of kernel functions (polynomial and radial basis function (RBF) kernels) on pillar stability data with four new categories: failed or intact, either with or without an appropriate safety factor. This classification…