Vol. 57 No. 6 (2025)

Carbon dioxide (CO2) is the primary contributor to greenhouse gas emissions. Ammonia (NH3) has emerged as a promising alternative fuel due to its high energy density, ease of transportation, and carbon-free molecular structure. However, its practical application is challenged by slow combustion characteristics and high ignition temperatures. This study investigates the combustion behaviour of ethanol-ammonia mixtures using a high-compression-ratio engine (17.7:1) equipped with a sub-chamber. The engine operated at a constant speed of 1000 rpm. Ammonia energy ratios of 40%, 50%, and 60% were…

Synthesis of carbon nanofibers from Gnetum gnemon Linn (GP) biomass with dual activators, KOH and melamine, offers a potential approach for high-performance supercapacitor electrodes. This study evaluated the preparation of GP-based carbon nanofibers through single and double activation, with varying melamine masses of 0.1, 0.3, and 0.5 g at 0.3 M KOH. The pyrolysis (integrated carbonization and physical activation) occurred at 600°C in N₂ and 800°C in CO₂ atmospheres. The material was activated using 0.3 g of melamine in 0.3 M KOH to produce abundant and highly amorphous nanofiber…

In the development of high-speed trains, evaluating the crashworthiness of passenger car structures is essential, particularly in the vestibule area which designed to absorb impact energy. When constructed entirely from aluminum extrusion, the vestibule exhibits high stiffness and uncontrolled energy absorption, resulting in excessive deceleration during collisions. This study investigates the crashworthiness of the vestibule structure in Indonesian high-speed train trailers, referencing EN 15227/SNI 8826 and 49 CFR 238 standards. A numerical analysis was conducted using ANSYS LS-DYNA,…

Investigation of the V-bending process with the effect of V-grooving insert geometries is performed through finite element analysis within ANSYS LS-DYNA. Different V-groover geometries are tested to evaluate the effect on the final bent angle and bent radius of the sheet metal part, with the objective of obtaining the minimized bent angle and bent radius results. It is also observed that the corner radius of the V-groover has a major influence on the bent angle and bent radius. Due to the removal of material in the bending region, which reduced the bending resistance, an increase in the…

Multi-criteria decision-making methods including the Extended Additive Ratio Assessment (EAMR), Simple Additive Weighting (SAW), Weighted Aggregated Sum Product Assessment (WASPAS), and Evaluation based on Distance from Average Solution (EDAS) were employed in conjunction with the Taguchi method and finite element method (FEM) to optimize the displacement amplification of an amplifying compliant mechanism utilizing flexure joints. Initially, design variables for the compliant mechanism amplifier were selected. Minitab software was utilized to generate 27 experimental scenarios, and SolidWorks…

Rockbursts are destructive accidents that often occur in underground mines. With the advancement of technology, machine learning has emerged as an alternative solution that can be used for rockburst mitigation. In this research, we classify rockburst events and their intensities in underground mines using two machine learning models: grey wolf optimization–support vector machine (GWO–SVM) and extreme gradient boosting (XGBoost). Rockburst events are classified into two categories: Existent and None. Meanwhile, the intensities are classified into three categories: weak, moderate, and strong.…

In view of the problems such as low luminous efficiency, poor stability and weak anti-interference ability of traditional electrochemiluminescence sensors, this study prepared graphdiyne oxide quantum dots by acid oxidation method and synthesized metal-organic skeleton derived zinc oxide by high-temperature calcination. The two were combined to construct a new ECL sensor. It is used for detecting free radicals and antioxidants such as vitamin C, trixerutin, and metformin hydrochloride. The results showed that GDYO-QD was successfully combined with M-ZnO. The constructed sensor has excellent…

This paper has analyzed the thermal insulation of geopolymer blocks prepared using palm oil ash (POA) with the addition of alumina powder (AP) and field Para rubber latex (FPRL). The block samples were set up to use 3 and 5 channels and channel width of 2 and 4 mm each with geopolymer binder as POA (containing 5% FPRL and 0%, 2.5%, 5%, 7.5%, and 10% AP) and POC as fine aggregate. The compressive strength, water absorption, bulk density of the geopolymer mortars and thermal conductivity of geopolymer blocks were explored. The AP and FPRL had minimal impact on the compressive strength of the…

Maternal health and fetal growth in rural areas require special attention due to limited access to adequate healthcare systems. Early detection of fetal health conditions can be achieved using B-mode ultrasonography (USG). However, expectant mothers in these regions often lack regular to regular check-up, even when healthcare facilities are available there may not be trained professionals available to analyze the B-mode images obtained in the Community Health Centres. To address this gap, a tele-USG system was developed that allows healthcare workers in remote areas to operate basic USG…

Surface-Enhanced Raman Spectroscopy (SERS) is a highly effective technique for detecting trace amounts of molecular species. However, the widespread use of conventional noble metal substrates is limited by high fabrication costs and scalability issues. Perovskite materials have recently emerged as promising alternatives, though many are lead-based and pose environmental risks. In this study, we present a lead-free bismuth ferrite (BiFeO₃) perovskite synthesized via the sol–gel method as a novel SERS substrate for the detection of Rhodamine B, a toxic dye commonly used illicitly in food…