Journal of Engineering and Technological Sciences
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3D Modeling of Leachate Distribution Around Zone E of Batu Layang Landfill, Pontianak, West Kalimantan, Indonesia Using the Geoelectrical Method
Full text linkOpen dumping systems as implemented by the Batu Layang landfill in Pontianak City, Indonesia can cause leachate pollution in the environment. The constituent soil condition affects the leachate distribution into the ground. One of the landfill constituents of the soil at the site of the Batu Layang landfill is peat soil, in which organic content (>75%), porosity, and permeability are high. Leachate that seeps below the earth’s surface can cause soil and groundwater contamination. Meanwhile, people around landfills use groundwater for their daily needs and use the land around the landfill to grow papaya, banana, sugarcane, and taro. Therefore it is necessary to prevent and minimize leachate spread. One of the efforts that can be done is to model the leachate distribution. In this study, leachate distribution modeling was done with a geoelectric method, the Wenner configuration, with a smallest electrode distance of 5 m. There were six tracks, with a length of 195 m each. The model obtained from this study was a 3D resistivity section. 3D data processing was done using the inverse distance method. The results showed that a resistivity value ≤10 Ωm identified the soil layer contaminated with leachate. The contaminated soil layers were estimated to be peat, clay, and loamy sand. The leachate distribution is suspected of seeping up to 195 m south of the landfill. The leachate distribution into the soil was estimated from the surface to 33.8 m
A Comparative Study of Solid-State and Co-precipitation Methods for Synthesis of NMC622 Cathode Material from Spent Nickel Catalyst
Full text linkNickel, the main raw material for lithium-ion batteries (LIB), is currently the most in-demand metal. The rising need for nickel and current environmental concerns have underscored the importance of recycling waste metal to recover its value. Meanwhile, a significant secondary source with a high metal value is spent catalyst. In this context, the acid leaching method was used to recover nickel from spent catalyst. This study aimed to synthesize Lithium Nickel Manganese Cobalt Oxide 622 (NMC622) from spent catalyst. To determine the optimal method, a comparative analysis was conducted between solid-state and co-precipitation methods. Recycled spent nickel catalyst to be used for cathode material was examined by analytical methods, i.e., XRD, FTIR, SEM-EDX, and electrochemical performance testing. The XRD, FTIR, and SEM-EDX tests produced similar outcomes, consistent with previous reports. However, in the electrochemical test, the co-precipitation method showed a specific capacity two times higher than the solid-state method. The NMC622 from the co-precipitation method (NMC622-CP) yielded a specific discharge capacity of 132.82 mAh.g-1 at 0.1C, while the retention capacity was 70% for 50 cycles at 0.5C
The Effect of Coconut Powder on Asphalt Binder Performance under Laboratory Conditions
Full text linkBituminous concrete mixture is the most widely used structural layer in flexible pavements. The surface layer of the paving is exposed to repeated loads in addition to changes in temperature, especially during the summer, when the temperature approaches the softness point of the asphalt binder, and therefore, it is subject to multiple types of failure, especially rutting. The properties of asphalt binder and asphalt mixtures can be improved by using various additives. Coconut shell powder, made from the dried husk of coconut fruit, is a popular addition in many industries. As a result of its high strength and stability, this waste material can be recycled into functional structural components such as composite material reinforcement. This study was conducted to evaluate the performance of coconut husk as very fine particles passing through sieve number 200 (0.075 mm) to modify the asphalt binder. The modifier was added at rates of (0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10) by the weight of asphalt binder. Two asphalt binder types, 80/100 and 40/50 penetration grade, were used in this study. All asphalt samples were tested for penetration, softening point, rotational viscosity, and dynamic shear rheology. The results showed that the modified samples had better physical and rheological properties compared to the base asphalt binders. However, (7-8%) replacement of coconut husk powder, regardless of the base asphalt binder, yielded the best performance among the modified binders. In conclusion, coconut powder has significant potential as a road-building material due to its impact on the viability of the road construction secto
Assessment of Small-Scale Microplastics Abundance and Characterization in Urban River: A Case Study in Metro River, Indonesia
Full text linkMicroplastic pollution is a pressing environmental concern with detrimental effects on aquatic ecosystems and human health. This study aimed to investigate microplastic contamination in a rapidly urbanizing area along a river and to examine the spatial distribution of microplastic abundance across the study area based on land use type. Seven sampling points were selected along the study site and microplastic samples were extracted using density separation and wet peroxidation (WPO) methods. The characteristics of the microplastic particles, including size, color, shape, and abundance, were analyzed to understand their properties. The results indicated that the microplastic abundance values ranged from 28.33 to 133.00 particles/liter, with an average of 73.55 particles/liter. Small microplastic particles (SMP), with sizes ranging from 1 μm to 1 mm, along with fragment shapes, and clear colors were predominant in the study area. A generalized additive model was utilized to assess the relationship between land use and microplastic abundance. The model demonstrated a significant influence of built-up areas on the presence of microplastics (p-value < 0.05), with an r2 value of 0.76. Residential areas near the river were identified as the likely primary sources of the microplastics
Integrated D-InSAR and Ground-based Radar for Open Pit Slope Stability Monitoring and Implications for Rock Mass Young’s Modulus Reduction
Full text linkExcavation and material stockpiling activities in the mining process cause a change in the distribution of forces and stresses in the material. As a result, the material will seek a new equilibrium by releasing the load through a landslide. As part of mitigation, it is necessary to monitor displacements occurring on slopes using high-accuracy devices. Ground-based radar is a technique considered to have good ability to detect displacements in real-time. However, ground-based radar has a weakness in that it cannot detect vertical displacement. One of the emerging technologies that is used for monitoring vertical displacements as LoS displacements is D-InSAR analysis. With the integration of both methods, displacements that occur horizontally and vertically on a slope can be detected properly. In addition, the decrease in rock mass strength due to displacement can be predicted based on numerical analysis using the finite element method. Monitoring was carried out from December 10th, 2021 to April 9th, 2022. The monitoring results from the beginning to the end of the period showed that the horizontal and vertical displacements that occurred in the low wall area were 1247.34 mm and 292.5 mm, respectively. Correlated with these conditions, the Young’s modulus value of the rock mass decreased between 3% and 35%
The Economic and Safety Improvement Feasibility of Urban Ocean Fishing Port Modernization – Study Case of Nizam Zachman
Full text linkThe Nizam Zachman Jakarta Ocean Fishing Port (PPSNZJ), the largest fishing port in Indonesia, is currently experiencing overcapacity. This results in ships being moored in rows parallel to berths, indicating the insufficient number of berths in the port. This configuration poses a safety hazard due to the proximity of the moored ships, making it challenging to evacuate them in the event of a fire or other natural disasters. This study was conducted to propose an alternative concept for facility development in urban ocean fishing ports, with PPSNZJ as a study case. The study included a site visit to understand the actual berthing configuration of ships, data collection from the port technical execution unit, and observation of existing fish cargo handling operations. The collected data was analyzed to determine berth capacity and storage productivity, which was used to calculate the number of additional berths required to accommodate loading, unloading, and mooring ships. Based on the design calculations, an alternative development layout is proposed, which fulfils the berth capacity and safety requirements. This study also revealed that the development cost is relatively competitive compared to similar projects
Feature Extraction Evaluation of Various Machine Learning Methods for Finger Movement Classification using Double Myo Armband
Full text linkThe deployment of electromyography (EMG) signals attracts many researchers since it can be used in decoding finger movements for exoskeleton robotics, prosthetics hand, and powered wheelchair. However, decoding any movement is a challenging task. The success of EMG signals' use lies in the appropriate choice of feature extraction and classification model, especially in the feature extraction process. Therefore, this study evaluates an eight-feature extraction evaluation on various machine learnings such as the Support Vector Machine (SVM), k-Nearest Neighbor (k-NN), Decision Tree (DT), Naïve Bayes (NB), and Quadratic Discriminant Analysis (QDA). The dataset from four intact subjects is used to classify twelve finger movements. Through 5 cross-validations, the result shows that almost all feature extractions combined with SVM outperform other combinations of features and classifiers. Mean Absolute Value (MAV) as a feature and SVM as a classifier highlight the best combination with an accuracy of 94.01%
