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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 132 Documents
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Classical Mechanics Theory and Schrödinger's Equation: A Derivation of Relations Li, Jiancao; Yu, Yanchun
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
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.2025.57.5.1

Abstract

This study examines integrating the Schrödinger equation with classical mechanics using a virtual axis-to-dimensional expansion. One-dimensional material fluctuations are viewed in a two-dimensional plane, explaining the random nature of these fluctuations and their spatial and temporal trajectories. A quantum-consistent force field is proposed, with its strength determined by the Planck constant and inversely proportional to the distance from the stationary point. Newton's second law is applied to establish a second-order linear differential equation for material fluctuations, from which the standard one-dimensional Schrödinger equation is derived, showing their equivalence. The study extends the three-dimensional Schrödinger equation to include external forces and explains quantum phenomena like energy levels and transitions through particle trajectory changes. This approach connects classical mechanics and quantum mechanics, offering a concise and intuitive formulation with clear physical significance.
Low Machining Parameters Produce High Cutting Performance when Machining AISI 1045 at Dry Cutting Conditions Using a CNC Lathe Machine Rashidi, Iqmal Farhan; Tamin, Norfauzi; Rani, Ridhwan; Azlan, Umar Al Amani; Wahab, Norfariza Ab; Ismail, Anwar; Darmawan, Agung Setyo
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
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.2025.57.5.2

Abstract

AISI 1045 medium-carbon steel is widely used for machining because of its excellent machinability. It balances strength and workability in various manufacturing applications, including machinery parts, gears, mold pins, automotive parts, crankshafts, bolts, and studs. The most significant disadvantage of AISI 1045 machining is that if the cutting parameters are not managed appropriately, it can affect the efficiency of the machining process, which involves tool life and product surface finish at dry cutting conditions. This study aims to determine suitable cutting parameters for AISI 1045, identify the optimum minimum tool wear (VB), and assess surface roughness (Ra). This study used various machining parameters at a cutting speed (Vc) of 35–53 m/min, feed rate (fr) of 0.15, and 0.5 mm/rev at a 1 mm constant depth of cut (DOC). The results showed that a Vc of 35 m/min and a fr of 0.15 mm/rev obtained the lowest average VB of 0.07 mm and Ra of 3.8 µm. This study found that low machining parameters produce high dry-cutting performance. This study provides guidelines for machinists to use appropriate cutting parameters when machining AISI 1045 under dry-cutting conditions at short machining times. In addition, it promotes sustainable machining and prevents air pollution from using coolants (chemical reactions).
Development of Solar-Powered Automatic Pest Trap for Rice Cultivation Plants in Indonesia Telaumbanua, Mareli; Khotimah, Khusnul; Wisnu, Febryan Kusuma; Rahmawati, Winda; Haryanto, Agus; Fil'aini, Raizummi
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.5

Abstract

Rice is the main commodity processed into rice, as a staple food for the people of Indonesia. Pests and diseases can cause decreased production to crop failure. The method used by farmers is pest control by spraying chemical pesticides. However, chemical pesticides have serious impacts on plants, increased immunity for pests, increased chemical residues in crops that threaten human health, and environmental pollution. The objective of this study is to design an integrated high-tech trap that is effective, efficient, cost-effective, durable, safe, environmentally friendly (zero-emission), and low in operational costs, with the ultimate goal of enhancing farmers' income. This automatic pest trap embeds a microcontroller, infrared sensor, fan and solar panel. Observations were made on 4 tools, namely complete lures, yellow LED, lights and pheromones. Based on the observations, Scotinophara coarctata and Nilaparvata lugens were identified as the most commonly trapped insect pests in rice fields. The insect's fall speed was fast, namely 1 minute 4 seconds with good stability. Insect readings came in higher on the complete lure due to the combination of three lures, each of which has its own insect attraction. The effectiveness of insect capture on the complete automatic insect trap was the highest at 84.47%.
Financing Model for Construction and Demolition Waste in Indonesia Susilowati, Fajar; Prakoso, Jalu Aji; Adipradana, Arrizka Yanuar
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.6

Abstract

Construction waste poses a significant environmental and economic challenge in Indonesia’s rapidly expanding construction sector. This research develops a financing model for managing construction waste throughout the project life cycle, emphasizing the integration of cost components and waste management strategies. Data were collected through surveys, structured interviews, and observations from 80 construction projects across Indonesia. The analysis revealed that while reinforcement, bricks, and split stone have high recycling potential, actual reuse remains limited due to poor planning and insufficient infrastructure. Seven financing components were identified: material loss, production/management, sorting, collection, transportation, recycling, and dumping. Notably, material loss accounts for the largest cost share—up to 10% of project value—while recycling and dumping costs are underfunded at 0.01%–0.5%. A cost-based model was developed to simulate waste-related expenses, ranging from 0.39% to 20.5% of overall project costs. The research also highlights the design stage as a critical leverage point for maximizing waste reduction. By aligning financial planning with life cycle stages, this research provides practical guidance for stakeholders and supports Indonesia’s transition to a circular construction economy through better budgeting, policy development, and waste strategy implementation.
Modification of Polylactic Acid with Eggshell Filler as Biodegradable Composite Sambudi, Nonni Soraya; Radini, Fitri Ayu; Ahmad Kamal, Norashikin; Jusoh, Norwahyu
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.7

Abstract

In this study, polylactic acid (PLA) was proposed as a material for producing bioplastics due to the desirable properties, including high processability, low cost, and good transparency. However, the degradation of PLA as a bioplastic remains a significant challenge. To address this problem, PLA was modified by blending with a bio-filler, in the form of calcium carbonate (CaCO3) prepared from eggshell powder (ESP). The CaCO3 filler in form of ESP was incorporated into PLA using the solution casting method. The parameter being varied was the ESP loading, ranging from 0 wt% to 20 wt%. The results showed that the inclusion of eggshell-derived filler in PLA increased tensile strength and Young’s modulus by 10%, from 24.12 to 26.61 MPa, and 162%, from 3022 to 7932 MPa, respectively. The degradability of composite was done through burial test, which the weight of PLA/ESP-20wt% was decreased by 11.11 wt% after 3 weeks. This suggests that eggshell waste has the potential to serve as an effective filler to improve the mechanical strength and degradation of PLA.
Comparative Analysis of DTC-controlled TSTPI and FSTPI Inverters for Low-power Photovoltaic Applications Imen, Nouira; El Badsi, Bassem
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
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.2025.57.5.3

Abstract

The increasing global shift towards renewable energy (RE) has amplified the need for efficient and cost-effective DC/AC converters in photovoltaic (PV) systems. This paper focuses on evaluating the performance of reduced structure inverters, specifically the Three Switch Three Phase Inverter (TSTPI) and the Four Switch Three Phase Inverter (FSTPI), both operating under Direct Torque Control (DTC), for low-power PV applications. A novel DTC strategy has been developed and applied to the TSTPI to improve control precision and overall performance. Through extensive simulations in Matlab/Simulink, complemented by experimental validation on a dSPACE1104 platform, we assess and compare the operational efficiency, harmonic distortions, and electromagnetic torque oscillations of both inverter structures.The findings reveal that, while both the TSTPI and FSTPI demonstrate satisfactory results, notable differences arise in terms of efficiency and harmonic distortion levels. These results highlight the suitability of reduced structure inverters for low-power PV applications, offering an attractive balance between cost and performance.This study provides valuable insights that can guide future developments in the design and real-time implementation of inverter systems tailored for RE applications.
Facile and Environmentally Friendly Synthesis of Low-defect Few-Layers Graphene (FLG) Using Combined Shear Exfoliation Methods Amri, Amun; Wulandari, Revika; Fabryza, Dhina; Sunarno, Sunarno; Heltina, Desi; Bahri, Syaiful; Sarma, Deki; Miran, Hussein A.; Rahman, M. Mahbubur; Altarawneh, Mohammednoor; Jiang, Zhong Tao
Journal of Engineering and Technological Sciences Vol. 57 No. 5 (2025): Vol. 57 No. 5 (2025): October
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.2025.57.5.4

Abstract

This study presents an environmentally friendly and scalable method for synthesizing high-quality few-layer graphene (FLG) through a combination of turbulence-assisted shear exfoliation (TASE) and high shear exfoliation (HSE) techniques. By systematically varying the high-shear mixer (HSM) speed (3000–5000 rpm) and processing time (1–3 hours), we precisely controlled key material attributes, including the number of graphene layers, crystallinity, lateral size, and defect density. Optimal conditions (5000 rpm, 3 hours) resulted in FLG with ~2–3 layers, confirmed by a symmetric 2D peak with a full-width at half-maximum (FWHM) of ~35 cm⁻¹ and a high I2D/IG ratio (~0.6), indicating excellent structural integrity. The ID/IG ratio (~0.1) further verified the presence of minimal defects, predominantly edge vacancies rather than oxidative disruptions. Raman imaging revealed a dominance of zigzag edge chirality, while TEM and PSA analyses demonstrated control over lateral size (~396.5 nm) and particle uniformity. The application of household dishwashing liquid as a green surfactant innovatively enabled selective and pure exfoliation. This work highlights how precise modulation of shear parameters can directly influence graphene quality, paving the way for sustainable large-scale production of low-defect FLG.
Real-time Assessment of ECG Classification based on Time-series Data and Other Types of Features Tran, Thanh-Luan; Thai, Bao-Toan; Tran, Vy-Khang; Nguyen-Thi, Xuan-Nhi; Nguyen, Chi-Ngon; Nguyen, Van-Khanh
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.8

Abstract

Cardiovascular diseases are the leading cause of mortality worldwide. An increasing number of studies have applied artificial intelligence (AI) to identify anomalies and classify electrocardiograms (ECGs), supporting early detection and diagnosis. This study proposes and evaluates the classification of ECG signals based on time-series data and features extracted via fast Fourier transform (FFT) and discrete cosine transform (DCT), implemented on resource-limited microcontroller units (MCUs) for selected AI models. Two models, the artificial neural network (ANN) and the convolutional neural network (CNN), were proposed for classifying five common ECG labels. These models were trained and tested with three types of input data: time-series data, FFT features, and DCT features, sourced from an available database. After training, the optimized models were quantized to assess their accuracy before being deployed in real-time to measure inference time on the ESP32 MCU. Before quantization, the ANN model achieved the highest accuracy with both DCT and time-series inputs (98.0%); meanwhile, the CNN model performed best with time-series input (97.0%). After quantization, the ANN maintained the highest accuracy with time-series input (97.1%), followed by the ANN with DCT at 95.6%. CNN models remained stable, with post-quantization accuracy of 95.8% for time-series input, 94.9% for DCT, and 90.0% for FFT. In contrast, ANN with FFT input showed a significant drop to 65.6%.
Design of Solar-powered Automatic Shrimp Feeder based on the Internet of Things Technology Boonraksa, Terapong; Boonraksa, Promphak
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.9

Abstract

This paper presents the design and implementation of a solar-powered automatic shrimp feeder utilizing IoT technology to enhance efficiency and precision in aquaculture. The core of the system is the DC motor operated feeder mechanism, and is capable of user defined customization like feeding scheduling, speed control, real time system monitoring etc. from distance through IoT integration via a smartphone. The motor speed can be adjusted to 1000, 1500, and 2000 rpm as per the requirement. Additionally, system can also monitor other water quality parameters like water temperature, pH and DO values, which are displayed via a smartphone. The experimental results confirm that the feeder perform as expected, it is capable of dispensing 5 kg of feed within 54 second, feeding up to 4.5 m depth when operating at 2000 rpm while consuming just 178.92 W power. The feeder is designed to autonomously determine its operating schedule, with users having the flexibility to adjust the timing at any point through the mobile application. This automation ensures consistent and efficient feeding aligned with aquaculture needs. Furthermore, the study includes a comprehensive cost analysis. The use of solar power and automation led to an annual cost reduction of 83.18% compared to manual labor. Over a ten-year period, the system achieved a total cost savings of 96.78%, amounting to 1,460,000 baht. Beyond enhancing feeding efficiency, the integration of IoT in shrimp farming substantially lowers labor expenses, contributing to a more sustainable and economically viable farming model.
Comparative Study on Magnetic Activated Carbon Derived from Delignified and Non-delignified Palm Kernel Shell: Synthesis, Characterization, and Methylene Blue Adsorption Analysis Waluyo, Joko; Nabila, Zahrani Putri; Putra, Ariadi Indra; Purba, Ibnu Tryansar; Izzulhaq, Muhammad Ghozy; Kurnia, Irwan; Septian, Ardie; Ernawati, Lusi
Journal of Engineering and Technological Sciences Vol. 57 No. 4 (2025): Vol. 57 No. 4 (2025): August
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.2025.57.4.10

Abstract

Indonesia is the global leader in palm oil production, but it deals with significant challenges in managing palm oil mill waste, particularly palm kernel shells (PKS). This study investigated palm kernel shell (PKS) as a precursor for synthesizing magnetic activated carbon (MAC) to enhance its performance as an adsorbent for liquid waste treatment.  The precursor was delignified using alkali liquor and magnetized by incorporating Fe²⁺ and Fe³⁺ ions, followed by chemical activation (ZnCl₂) through an intermediate pyrolysis process. The performances of delignified and non-delignified MAC (DMAC and NDMAC) were evaluated through methylene blue adsorption tests (25–45 mg/L), focusing on adsorption capacity, dye removal efficiency, as well as isotherm and kinetic analysis. DMAC demonstrated a larger surface area, leading to enhanced adsorption performance. Morphological analysis revealed that delignification had a positive influence on the pore structure and size, resulting in a more uniform distribution. DMAC exhibited an adsorption capacity 16.3% higher (35.3 mg/g) in the equilibrium phase and 16.6% higher at maximum adsorption capacity (50.25 mg/g) according to the Langmuir isotherm. Furthermore, the inclusion of iron ions (Fe2+/Fe3+) promoted pore expansion and formation in the precursor material. The study found the Langmuir isotherm model (R² = 0.999) to be the best fit for methylene blue adsorption, while the pseudo-second-order kinetic model (R² = 0.9958) demonstrated an excellent fit for adsorption kinetics. The findings confirm that DMAC and NDMAC derived from PKS are effective for methylene blue dye adsorption, technically.

Page 11 of 14 | Total Record : 132

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