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Yuliah Qotimah
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Journal of Engineering and Technological Sciences
Published by Institut Teknologi Bandung
ISSN : 23385502     EISSN : 23375779     DOI : 10.5614/j.eng.technol.sci
Core Subject : Engineering,
Aerospace Engineering Automotive Engineering Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Electrical & Electronics Engineering
ournal of Engineering and Technological Sciences welcomes full research articles in: General Engineering Earth-Surface Processes Materials Science Environmental Science Mechanical Engineering Chemical Engineering Civil and Structural Engineering Authors are invited to submit articles that have not been published previously and are not under consideration elsewhere.
Arjuna Subject : Teknik (semua kategori) - Teknik (Lain-Lain)
Articles 11 Documents
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Search results for , issue "Vol. 56 No. 3 (2024)" : 11 Documents clear
Investigation of Liquefaction in Balaroa, Petobo, and Jonooge (Central Sulawesi, Indonesia) Caused by the 2018 Palu Earthquake Sequence Triyono, Rahmat; Widiyantoro, Sri; Zulfakriza, Zulfakriza; Supendi, Pepen; Rahman, Aditya Setyo; Gunawan, Mohamad Taufik; Oktavia, Nur Hidayati; Rahmatullah, Fajri Syukur; Fadhilah, Fildzah Zaniati; Habibah, Nur Fani; Sativa, Oriza; Permana, Dadang; Wallansha, Robby; Octantyo, Ardian Yudhi; Persada, Yoga Dharma; Pranata, Bayu; Sujabar, Sujabar
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.1

Abstract

The liquefaction that occurred in the city of Palu on September 28, 2018, was caused by a series of significant earthquakes that took place in a relatively short time around 25 minutes after the main earthquake of magnitude 7.5. This event was followed by aftershocks of magnitudes 6.4, 6.2, and 6.1. The magnitude 6.2 aftershock occurred at 10.16 UTC, while the magnitude 6.1 aftershock occurred at 10.25 UTC. These were both located very close to the liquefaction locations in Balaroa, Petobo, and Jono Oge. We investigated the mainshock and the three aftershocks using the NCEER method based on Vs30 measurements and data from the drill liquefaction locations at Balaroa, Petobo, and Jono Oge. We found that the liquefaction was not only caused by the main earthquake but also by the subsequent aftershocks that occurred within 25 minutes after the mainshock.
Investigation of Impact Properties under Instrumented Charpy Test Zainuddin, Hikmah; Ali, Mohd Basri; Zakaria, Kamarul Ariffin; Paijan, Lailatul Harina; Mamat, Mohd Fauzi; Abu Bakar, Mohd Hadzley
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.2

Abstract

The Instrumented Charpy impact test is a promising method for determining a material’s impact response. Stainless steel has higher impact energy absorption capacity, high tensile, and yield strength compared to aluminum. Performance varies among grades; for instance, Aluminum 7075-T6 exceeds Aluminum 6061-T6 in tensile and yield strength. However, information regarding their energy capacity and impact signal pattern is lacking. This study investigated the impact properties using a Charpy machine, a data acquisition system, and a sensing element. Strain gauges were used to record the impact strain signal, enabling the analysis of impact duration, maximum strain, and the area under the curve. Specimens experimented include Stainless Steel 304, Aluminum Alloy 6061-T6, and Aluminum Alloy 7075-T6. The Charpy machine measures absorbed energy, while the theoretical impact energy is computed from software data. The area under the strain-time curve reflects the material energy absorption capacity. Stainless Steel 304 demonstrates superior energy absorbed, impact duration, and area under the curve, followed by Aluminum 6061-T6 and Aluminum 7075-T6. Despite higher tensile and yield strength, the inferior impact response of Aluminum 7075-T6 highlights the importance of factors like ductility, elongation, and alloy composition. Consequently, Aluminum 6061 is commonly used in the automotive industry, while Aluminum 7075 is preferred in aerospace applications.
Design and Experiment of Nighttime Greenhouse Tomato Harvesting Robot Liu, Lei; Yang, Qizhi; He, Wenbing; Yang, Xinyu; Zhou, Qin; Addy, Min Min
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.3

Abstract

In response to the issue of high tomato yield, low efficiency in harvesting tomatoes grown in greenhouses, and low recognition accuracy of nighttime harvesting robots, a design was developed and a robotic system was created specifically for nighttime greenhouse tomato harvesting. The robot employs a vision system and YOLOv5+HSV fusion algorithm to recognize and locate tomatoes. It then transmits this information to the robotic arm. By coordinating the visual system, the robotic arm, the end effector, and the lifting mechanism, the robot accurately picks ripe tomatoes. The robot was subjected to simulated field tests for visual recognition and harvesting, both during daytime and nighttime conditions. The results showed that the success rate of nighttime harvesting was slightly lower than during the daytime but remained at a relatively high level. The daytime harvesting success rate and the average time to pick a single fruit were 87.78% and 15.99 seconds, respectively. The nighttime harvesting success rate and the average time to pick a single fruit were 87.55% and 17.26 seconds, respectively. This approach effectively improves the recognition accuracy and harvesting speed of the harvesting robot, reducing damage to tomatoes during harvesting, and addresses the issues of supplementary lighting and image noise reduction for nighttime harvesting robots.
Research on Lightweight Rail Vehicle Body Based on Sensitivity Analysis Yin, Jian; Zhang, Qingchao; Li, Xianglong; Zhu, Yaoyao; Liu, Ziyuan; Liu, Yu; Sha, Zhihua
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.4

Abstract

In view of the development trend of rail vehicles towards higher operating speed and low power consumption, a scheme for a lightweight rail vehicle body is proposed, based on sensitivity analysis. Using topology optimization of the vehicle body section structure, finite element models of the vehicle body section structure under single working conditions and multiple working conditions were established, respectively, and the force transmission path of the vehicle body structure under different working conditions was obtained under different working conditions. The topology of the cross-sectional structure of the vehicle body was optimized by the compromise planning method with weights. Then, a reconstruction and performance analysis of the car body section was carried out based on the optimization results and finally the finite difference method was used to analyze the sensitivity of the vehicle body structure and the vehicle body size was optimized based on the sensitivity analysis results. The results showed that the weight reduction rate of the railway vehicle body section stiffened plate was 4.47% compared to the optimization period and the modal performance analysis results of the optimized structure met the requirements. The weight reduction ratio of the optimized body structure was 21.6%
Wide Bandgap SiC-Based Oxide Thickness Optimization by Computation and Simulation using Enhanced Electron Mobility with Regulated Gate Voltage Technique for High-Power 4H-SiC MOSFET Poobalan, Banu; Hashim, Nuralia Syahida; Natarajan, Manikandan; Rahim, Alhan Farhanah Abd
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.5

Abstract

This work analyzed the interactions between gate oxide thickness (Tox), voltage dependence, and electron mobility (E-mobility) in the inversion layer, which controls the electron movement properties of 4H-SiC/SiO2. This paper also presents a calculation of gate oxide thickness in correlation with gate voltage mainly for high-voltage applications. The results of this work revealed that at low resistance, E-mobility increases with gate voltage and oxide thickness, which saturates at the point of value. Coulomb scattering and surface phonons at the inversion region of SiC MOSFETs are regarded as the two primary factors that limit E-mobility in these devices. In addition, the high interface trap density (Dit) causes a decrease in E-mobility. The findings from this study confirmed that the computed values of oxide thickness and simulation-based oxide thickness with regulated gate voltages have the least variation below 1%, asserting experimental and theoretical outcomes about the role of oxide thickness and electron movement at the 4H-SiC/SiO2 interfaces. These results indicate that understanding the E-mobility effect on oxide thickness in the SiC MOSFET inversion layer according to gate voltage is important, particularly in achieving an optimal 4H-SiC/SiO2 interface for high-power applications.
Box Station Parametric Study with Time History Dynamic Analysis Sengara, I Wayan; Basarah, Yuamar I.; Sulaiman, Ahmad; Sibagariang, Sarah M.T.
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.6

Abstract

The performance of an underground station structure subjected to an earthquake can be evaluated by looking at deformation as well as forces and bending moments that occur in the structure. Most design practices adopt simplified approaches, such as the free field deformation method and pseudo-static approaches, which have a high level of uncertainty. Therefore, it is necessary to perform dynamic time-history analysis to verify the results of the simplified approach. Dynamic modeling is considered a more appropriate approach because it better represents seismic shaking in evaluating the seismic response of underground structures. This study performed time-history dynamic analysis by conducting a parametric study. The study was conducted to determine the effect of parameters such as site class, peak base acceleration (PBA) ground-motion intensity, and the type of seismic mechanism on the deformation response. Based on the parametric study, it was found that the stiffer the site class, the smaller the relative deformation of the resulting underground structure. The greater the PBA intensity value, the greater the relative deformation. Relative deformation in the wall structure subjected to a subduction earthquake is more significant compared to that of a shallow crustal earthquake.
Physicochemical Properties and Sensory Acceptability of Fermented Roasted Robusta Coffee (Coffea canephora L.) Beans Chan, Hao Yuan; Rukayadi, Yaya; Azman, Ezzat Mohamad; Ashari, Rozzamri; Lim, Sarina Abdul Halim
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.7

Abstract

Spontaneous fermentation is becoming ever more elusive because of vast natural microbiota profiles that affect geographical region, climate, and applications of agrichemicals. This study aimed to identify the physicochemical and sensory properties of local planted (Serdang, Malaysia) Robusta (Coffea canephora L.) coffee beans after undergoing different spontaneous wet fermentation (SWF) periods i.e., 0 days as control, 3 days, and 5 days. The hardness decreased significantly (p < 0.05) by 80 to 90% in roasted fermented roasted Robusta coffee (FRRC) beans. The carbohydrate content was significantly higher (p < 0.05) at 9.4%, but protein and crude fibers were significantly (p < 0.05) lower at 31% and 9.7%, respectively. While the FRRC brew displayed deeper lightness (L*31.983), the FRRC powder displayed lighter lightness (L*49.553). The total soluble solid (TSS) was around 21% higher in FRRC and the water solubility index (WSI) had equivalent outcomes at about 8% higher in FRRC. Rheological analysis showed that the coffee fluid exhibited a shear-thickening property with fluid elastic components greater than viscosity. FRRC beans received higher ratings (score > 6) than non-FRRC beans (score between 5 and 6) in the consumer sensory evaluations.
Kriging Surrogate-based Optimization for Shape Design of Thin Electric Propeller Pholdee, Nantiwat; Bureerat, Sujin; Nuantong, Weerapon; Pongsatitpat, Boonrit
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.8

Abstract

This paper outlines an optimized propeller design for an unmanned aerial vehicle (UAV) employing a Kriging surrogate model-based optimization approach. The primary objective was to maximize propeller efficiency while adhering to the thrust-to-torque ratio constraint at a rotational speed of 6,500 rpm. The design variables encompassed the twist angle and the ratio of blade thickness to chord length across the twenty-section airfoil of the propeller. A comprehensive analysis was conducted using computational fluid dynamics to assess the aerodynamics of the propeller. The Kriging surrogate model serves as a valuable tool for approximating objective and constraint functions. The optimal Latin hypercube sampling technique was employed for design of experiment, generating a set of sampling points to construct a Kriging surrogate model. To tackle the optimization problem, seven metaheuristic optimizers were employed, including a genetic algorithm, particle swarm optimization, population-based incremental learning, differential evolution, teaching-learning based optimization, ant colony optimization, and an evolution strategy with covariance matrix adaptation. The obtained results revealed that Kriging surrogate model-based differential evolution optimization stood out as the most efficient method for addressing the propeller optimization problem. The propeller efficiency experienced improvement of approximately 0.6% compared to the maximum result obtained from the sampling points.
Exploration of the Influencing Factors of Intelligent Robots on College Network Education in the All-Media Era Chu, Na; Ma, Wanzhi
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.9

Abstract

Online public opinion incidents in universities occur from time to time, with the source difficult to find, rapid dissemination, and escalating fragmentation. There are many problems and difficulties in the guidance of online public opinion in universities, and a new way out needs to be explored. This article explores the influencing factors of intelligent robots on online education in universities in the all-media era. This article believes that the ecology of university online education is an inherent component of university online culture and is the result of the interaction and mutual restraint between various elements and external environmental factors. The self-regulation of each element gradually tends towards a harmonious and stable state. It is closely related to cultural ecology, network cultural ecology, and university network culture, and also has its own unique characteristics. Establish a collaborative governance model between university public opinion work alliances and society, improve the application standards of artificial intelligence and the management mechanism of IGM and MGC technologies. Compared with traditional technologies, intelligent robots in the all-media era can guide the network public opinion of colleges and universities in the intelligent Internet era.
Longitudinal Train Dynamics Model for CC203/CC206 Locomotive Simulator Hindersah, Hilwadi; Rohman, Arief Syaichu; Bayuwindra, Anggera; Rusmin, Pranoto H.; Kinasih, Fabiola M.T.R.; Machbub, Carmadi
Journal of Engineering and Technological Sciences Vol. 56 No. 3 (2024)
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2024.56.3.10

Abstract

This paper presents train modeling used in a simulator platform for driver training. It was developed for the CC203/CC204 locomotive. The driver will gain experience as in a real locomotive from the perceived platform movements if the movements match real conditions as accurately as possible, including the distance travelled. To this aim, a longitudinal model of the train was developed based on measurement data obtained from the Argo Parahyangan train traveling from Bandung to Jakarta. A second-order linear time invariant model was obtained by a black box identification approach, in which the input and the output of the model are the resultant force (a traction and a slope-friction force) and the train’s position, respectively. While the speed is directly obtained from measurement data, the traction force of the locomotive is predicted using the traction characteristic of the locomotive, train’s measured speed, and latitude time history during a train trip. The model is then validated by running a simulation for one complete trip of the train. In the simulation, the same input as in the model identification is applied and the mileage obtained from simulation result is compared to data of the real train trip with a fitness level of 94.09%.

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