Vol. 58 No. 2 (2026)

This study investigates groundwater contamination caused by leachate migration at the Bakung landfill during the wet and dry seasons using geoelectrical resistivity and hydrogeochemical methods. The objective is to describe groundwater contamination resulting from leachate and assess groundwater quality from nearby wells along the edge of the Bakung landfill. 1D resistivity sounding (vertical electrical sounding (VES)) survey was conducted at eight sounding points using the Schlumberger configuration, and four lines of 2D resistivity imaging (electrical resistivity tomography (ERT)) were…

Chemical residue, particularly pesticide from agricultural activities at the Citarum Upper Watershed, is considered an evolving contaminant due to the presence in groundwater samples. Therefore, this qualitative study aims to identify four pesticide residues from organophosphate (OPP) and organochlorine (OCP). Groundwater grab sampling method was applied to collect 31 samples from each location. Extraction was then carried out using the QuEChER preparation technique, followed by gas chromatography-mass spectrometry (GC-MS) analysis. The results showed that Dichlorodiphenyltrichloroethane…

In this study, we explore the activity and selectivity of the CO2 reduction reaction (CO2RR) to CO and HCOOH on pure and transition metal-doped NiCoPO(100) surfaces using density functional theory (DFT) calculations. The novelty of this work lies in demonstrating that substitutional doping with Mn, Fe, and Cu significantly alters the thermodynamic landscape of CO₂RR, particularly in enhancing selectivity toward HCOOH. While CO remains the dominant product on most surfaces, Mn-doped NiCoPO(100) uniquely reverses this trend by reducing the limiting potential for HCOOH formation to a value lower…

The current global energy demand relies more on Combined Cycle Power Plants (CCPPs) for their high efficiency and reduced environmental footprint. However, the performance of these plants is very sensitive to several environment parameters including temperature, pressure, humidity, and exhaust vacuum. This paper is intended to use machine learning (ML) approach to model and optimize CCPP energy production based on these factors. The proposed method uses a dataset with hourly environmental measurements, to provide detailed analysis using ML techniques including Random Forests and Neural…

This study investigates a novel approach for using cutting fluids (CFs) under the influence of a permanent magnetic field during the turning of AISI 1045 steel with an AISI M2 high-speed steel (HSS) tool. Lubricating and cooling capacities are among the most critical characteristics of CFs. This research analyses the effect of magnetically treated CFs on tool wear and machining temperature. Two types of water-based CFs were employed in the experimental investigation: synthetic and emulsion. To assess the impact of magnetically treated CFs on machining performance, the flank wear (VB) of the…

This study investigated the regeneration of spent fluid catalytic cracking (FCC) catalysts, which become inactive due to the accumulation of poisons at active sites. The objective of the study was to enhance acidity by regenerating spent FCC catalysts through ultrasonic and oxidation processes (UAOPs) and evaluate their effectiveness in synthesizing glycerol monostearate (GMS). The results demonstrate that spent FCC catalysts regenerated with UAOPs can significantly increase catalyst acidity, which plays a crucial role in GMS synthesis. The optimal conditions identified were temperature X1…

The widespread use of conventional plastic packaging poses significant environmental challenges. As a sustainable alternative, bioplastics derived from cellulose sourced from agricultural waste are gaining interest. This study explores the development of biodegradable bioplastic films derived from durian rind cellulose, with glycerol used as a plasticizer. Cellulose was isolated from durian rind using chemical extraction methods, resulting in a 29% yield with 70.2% purity. Bioplastic films were synthesized by incorporating varying amounts of glycerol into the cellulose matrix. The successful…

This paper addresses the challenges of low tracking accuracy in the attitude and position control of quadrotor unmanned aerial vehicles (UAVs). To overcome these issues, a nonlinear hybrid control strategy is proposed by combining adaptive sliding mode control with Lyapunov theory. Accounting for the nonlinearities associated with the coupling among the UAV degrees of freedom, unlike simplified control-oriented models, the proposed strategy is designed to enhance trajectory tracking performance while improving control flexibility and robustness against external disturbances. The proposed…

Flash emissions from chemical storage tanks are a major source of volatile organic compounds (VOCs), accounting for over 90% of total VOC releases during storage. This study evaluated acrylonitrile emissions at a petrochemical facility using the Vasquez-Beggs Equation (VBE), TANKS 5.1, and the AERMOD dispersion model. Under midrange conditions, flashing losses were estimated at 12.84 g/s, with peak emissions reaching 18.17 g/s under high-pressure, low-temperature conditions. In comparison, breathing and working losses contributed only 0.0986 g/s and 0.2776 g/s, respectively, in uncontrolled…

Due to the rapid growth and expansion of the electricity industry, power systems worldwide are facing significant challenges that demand immediate attention to manage the increasing load. Many power system operators are struggling with insufficient power generation capacity. To mitigate the effects of limited power availability, reducing power losses and improving voltage profiles have become essential components of modern energy management. One effective approach to achieving these objectives in distribution networks is optimizing the placement of distribution transformers. In this study,…