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INDONESIA
Journal of Engineering and Technological Sciences
Published by Institut Teknologi Bandung
ISSN : 23375779     EISSN : 23385502     DOI : -
Core Subject : Engineering,
Engineering
Journal of Engineering and Technological Sciences welcomes full research articles in the area of Engineering Sciences from the following subject areas: Aerospace Engineering, Biotechnology, Chemical Engineering, Civil Engineering, Electrical Engineering, Engineering Physics, Environmental Engineering, Industrial Engineering, Information Engineering, Mechanical Engineering, Material Science and Engineering, Manufacturing Processes, Microelectronics, Mining Engineering, Petroleum Engineering, and other application of physical, biological, chemical and mathematical sciences in engineering. Authors are invited to submit articles that have not been published previously and are not under consideration elsewhere. Starting from Vol. 35, No. 1, 2003, full articles published are available online at http://journal.itb.ac.id, and indexed by Scopus, Index Copernicus, Google Scholar, DOAJ, GetCITED, NewJour, Open J-Gate, The Elektronische Zeitschriftenbibliothek EZB by University Library of Regensburg, EBSCO Open Science Directory, Ei Compendex, Chemical Abstract Service (CAS) and Zurich Open Repository and Archive Journal Database. Publication History Formerly known as: ITB Journal of Engineering Science (2007 – 2012) Proceedings ITB on Engineering Science (2003 - 2007) Proceedings ITB (1961 - 2002)
Arjuna Subject : -
Articles 1,267 Documents
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Numerical Solution of nth Order DAEM for Kinetic Study of Lignocellulosic Biomass Pyrolysis Jonas Kristanto; Muhammad Mufti Azis; Suryo Purwono
Journal of Engineering and Technological Sciences Vol. 55 No. 3 (2023)
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.2023.55.3.4

Abstract

The aim of the present study was to explore the most optimal configuration to numerically solve Distributed Activation Energy Models (DAEMs). DAEMs are useful in obtaining the kinetic parameters in non-isothermal kinetic studies using a thermogravimetry analyzer (TGA). Compared to other kinetic models, DAEMs provide an additional kinetic parameter that quantifies the extent of the reaction (σ) for each reaction’s mean activation energy (E ̅). Although DAEMs are efficacious in kinetic studies, solving DAEMs numerically is challenging. The DAEM equation includes double integration with respect to activation energy and temperature, which involves various numerical discretizations. Previously, many researchers utilized a DAEM to explicate complex reactions such as lignocellulosic biomass pyrolysis. However, most of them have yet to propose a numerical approach to solve DAEMs. Therefore, by exploring multiple numerical calculation configurations, here we present a general structure to numerically solve nth order and first-order DAEMs. The exploration includes determining the optimal integration limit of activation energy and the discretization of activation energy and temperature integration. From the investigation, we came up with a configuration that limits the integration of activation energy from E ̅-3σ to E ̅+3σ. Meanwhile, the number of integration points for temperature and activation energy must be 51 and 21, respectively. By using this configuration, DAEM can be utilized optimally in kinetic studies.
Compaction Control Using Degree of Saturation and Plasticity Index on Tropical Soil Hasbullah Nawir; Laras Dipa Pramudita; Tita Kartika Dewi; Dayu Apoji; Sugeng Krisnanto
Journal of Engineering and Technological Sciences Vol. 55 No. 3 (2023)
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.2023.55.3.5

Abstract

Soil compaction in the field is conventionally controlled using maximum dry density, (ρd)max, and optimum moisture content, (w)opt, as the target properties. However, achieving accurate control of these target properties can be difficult due to variation of compaction energy level (CEL) and soil type. Recently, a novel soil compaction control approach using optimum degree of saturation, (Sr)opt, as the target properties has been proposed. It was argued that (Sr)opt can be a better compaction control property as the value is less sensitive to the variation of CEL and soil type. This paper presents an investigation of the compaction characteristics of tropical soils from several locations in Indonesia based on both primary and secondary data. This study was performed by exploring the relationships between (i) dry density (ρd) and Sr, (ii) (ρd) and plasticity index (PI), (iii) (ρd) and CBR, as well as (iv) (ρd) and permeability. This study showed that the (Sr)opt of the soils was 91.2%, with variation between 81.2% and 96.5%. This study also showed that (ρd)max can be related to PI at a given CEL. It is expected that the proposed relationships can be better references for field compaction control practices in Indonesia.
Design and Characterization of Ultrasonic Langevin Transducer 20 kHz Using a Stepped Horn Front-Mass Aisyah Nurul Khairiyah; Gandi Sugandi; Deddy Kurniadi
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.1

Abstract

Ultrasonication is a method that is widely used in various fields. One of its applications is to accelerate the process of homogenization, emulsification, and extraction. In the ultrasonicator system, the transducer is an extremely important device. The resonant frequency, longitudinal vibration amplitude, and electromechanical coupling are the targets in designing an ultrasonic transducer. In this investigation, the main contribution was the development of a simple and effective method for mechanically tuning the resonant frequency of the transducer by adding mass to the front end of the mass or stepped horn. This study also aimed to obtain optimal results by examining the effects of geometric dimensions, bolt prestress, stress distribution, resonant frequency, amplitude, and electrical impedance. The ultrasonic transducer model was designed with a resonant frequency of 20 kHz and simulated using the finite element analysis. The steps involved included calculating the dimensions and geometric structure of the transducer, modeling using the finite-element method, and experimental validation. The simulation results and measurements showed that the series resonant frequency, electrical impedance, and effective electromechanical coupling of the Model-4 transducer 16∙13 mm radiator configuration were 20.15 kHz, 100 Ω, and 0.2229 from the simulation results, and 20.17 kHz, 24.91 Ω, and 0.2033 from the measurement results. A percentage difference, or relative error, of 0.1% was obtained between the simulation and the experimental results for this Model-4 with bolt prestressing at 15 kN.
Machine Learning-based Indoor Positioning Systems Using Multi-Channel Information Shu-Hung Lee; Chia-Hsin Cheng; Tzu-Huan Huang; Yung-Fa Huang
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.2

Abstract

The received signal strength indicator (RSSI) is a metric of the power measured by a sensor in a receiver. Many indoor positioning technologies use RSSI to locate objects in indoor environments. Their positioning accuracy is significantly affected by reflection and absorption from walls, and by non-stationary objects such as doors and people. Therefore, it is necessary to increase transceivers in the environment to reduce positioning errors. This paper proposes an indoor positioning technology that uses the machine learning algorithm of channel state information (CSI) combined with fingerprinting. The experimental results showed that the proposed method outperformed traditional RSSI-based localization systems in terms of average positioning accuracy up to 6.13% and 54.79% for random forest (RF) and back propagation neural networks (BPNN), respectively.
Al-Cu Composite’s Springback in Micro Deep Drawing Julian Widiatmoko; Fanghui Jia; Zhengyi Jiang
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.3

Abstract

With the recent technological trend of miniaturization in manufacturing industries, the rise of micro forming operations such as micro deep drawing (MDD) is inevitable. On the other hand, the need of more advanced materials is essential to accommodate various applications. However, a major problem are size effects that make micro scale operations challenging. One of the most important behaviors affected by size effects is the springback phenomenon, which is the tendency of a deformed material to go back to its original shape. Springback can affect dimensional accuracy, which is very important in micro products. Thus, this paper investigated the springback behavior of Al-Cu composite in MDD operations. Micro cups were fabricated from blank sheet specimens using an MDD apparatus with variation of annealing holding time. The springback values were measured and compared to each other. The results showed that different grain sizes lead to variation in the amount of springback. However, unlike in single-element materials, the amount of springback in Al-Cu composite is not only related to the thickness to grain size (t/d) ratio. Another factor, i.e., the existence of an interfacial region between layers, alters the mechanical behavior of the composite.
The Material Science Behind Repetitive Hammering, Solution Annealing, and Tempering on Hadfield Steel Ida Farida; Rochim Suratman
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.4

Abstract

The Hadfield steel used in this study contained 11 to 14% Mn and 1.1 to 1.4% C. Hadfield steel that underwent heat treatment showed insignificant differences in microstructure and hardness. On the other hand, Hadfield steel that was subjected to heat treatment combined with repetitive hammering exhibited changes in microstructure, as indicated by the presence of more and denser slip lines in accordance with an increased amount of deformation. The hardness value of the Hadfield steel also significantly increased. The slip lines discovered in the Hadfield steel that underwent solution annealing and tempering followed by repetitive hammering increased in number and appeared more compact than in the Hadfield steel without tempering. Additionally, the hardness value of the Hadfield steel with tempering was higher than that of the Hadfield steel without tempering. The strain values and thickness reduction results showed that the Hadfield steel subjected to tempering had higher strain and thickness reduction than the Hadfield steel without tempering. Higher strain and thickness reduction leads to higher hardness.
Selection of Material and Manufacturing Technology for Batik Canting Stamps Based on Multi-Criteria Decision-Making Methods Joni Setiawan; Andi Sudiarso; Isananto Winursito; Muhammad Kusumawan Herliansyah
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.7

Abstract

This study aimed to develop alternative materials and technologies for making canting stamps used in producing batik canting (stamped batik) to transfer hot wax from the pan to the fabric. Previous researchers have studied materials such as wood, aluminum, multiplex, acrylic, and acrylonitrile butadiene styrene (ABS). Manufacturing technologies have also been analyzed, including manual manufacturing, computer numerical control (CNC) milling, laser cutting, and additive manufacturing. However, none of these materials and technologies were considered suitable alternatives for copper canting stamps. This paper proposes Conductive ABS-Electroformed By Copper (CABS-EBC) through additive manufacturing and electroforming processes as alternative material for canting stamps. A multi-criteria decision-making (MCDM) approach was used to assess alternative materials and technologies. The alternatives and criteria were calculated using the Simple Additive Weighting (SAW), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), and Preference Ranking Organization Method of Enrichment Evaluation (PROMETHEE) techniques. Besides this, assessment was also carried out based on expert opinions. The results showed that copper was the most suitable material, with Closeness = 1.000, Yi = 0.995, and Phi = +1.00. Meanwhile, CABS-EBC ranked second, with Closeness = 0.627, Yi = 0.864, and Phi = +0.50. The selected technology was additive manufacturing combined with electroforming, with Closeness = 0.700, Yi = 0.895, and Phi = +0.39. By using MCDM on the material-technology development candidates it was found that CABS-EBC processed with additive manufacturing is capable of substituting copper as a canting stamp material. It is expected that the production capacity of the traditional manufacturing process can be enhanced by adopting these new materials and technologies.
Reducing Numerical Dispersion with High-Order Finite Difference to Increase Seismic Wave Energy: - Syamsurizal Rizal; Awali Priyono; Andri Dian Nugraha; Mochamad Apri; Mochamad Agus Moelyadi; David Prambudi Sahara
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.5

Abstract

The numerical dispersion of 2D acoustic wave modeling has become an interesting subject in wave modeling in producing better subsurface images. Numerical dispersion is often caused by error accumulation with increased grid size in wave modeling. Wave modeling with high-order finite differences was carried out to reduce the numerical error. This study focused on variations in the numerical order to suppress the dispersion due to numerical errors. The wave equation used in modeling was discretized to higher orders for the spatial term, while the time term was discretized up to the second order, with every layer unabsorbed. The results showed that high-order FD was effective in reducing numerical dispersion. Thus, subsurface layers could be distinguished and observed clearly. However, from the modeling results, the wave energy decreased with increasing distance, so the layer interfaces were unclear. To increase the wave energy, we propose a new source in modeling. Furthermore, to reduce the computational time we propose a proportional grid after numerical dispersion has disappeared. This method can effectively increase the energy of reflected and transmitted waves at a certain depth. The results also showed that the computational time of high-order FD is relatively low, so this method can be used in solving dispersion problems.
Photocatalytic Simulation of Phenol Waste Degradation Using Titanium Dioxide (TiO2) P25-Based Photocatalysts Wibawa Hendra Saputera; Jeffry Jaya Pranata; Reynaldo Jonatan; Pramujo Widiatmoko; Dwiwahju Sasongko
Journal of Engineering and Technological Sciences Vol. 55 No. 4 (2023)
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.2023.55.4.6

Abstract

Phenol waste treatment is vital in industries such as polymer production, coal gasification, refinery, and coke production. Photocatalytic technology using semiconductor materials offers an effective and ecofriendly approach to degrade phenol. TiO2 P25 is a widely used photocatalyst, known for its cost-effectiveness, favorable optical and electronic properties, high photoactivity, and photostability. The PHOTOREAC application, a recently developed MATLAB-based software, simulates the degradation of phenol using visible light. A study that combines existing literature and research revealed that pH significantly influences photocatalytic activity, with an optimum pH of 7 for TiO2 P25-mediated phenol degradation. The recommended photocatalyst concentration ranged from 0 to 10 g/L for reactor volumes between 25 and 60 mL, and from 0 to 5 g/L for 100-mL reactors. Phenol wastewater volume and light intensity also impact degradation efficiency. Adequate oxygen supply, achieved through bubbling and mixing, is essential for the formation of radical compounds. The Ballari kinetic model proved to be the most suitable for phenol degradation with TiO2 P25. Thus, by combining PHOTOREAC simulations with experimental data, the treatment process could be optimized to achieve higher degradation efficiency and estimate the treatment time for specific waste degradation levels. This study contributes to the advancement of phenol waste treatment and the development of improved photocatalytic wastewater treatment technologies.
Structural Analysis and Service Life Prediction of Rubberized Thin Surfacing Hot Mix Asphalt Sebastianus Kristianto Nugroho; Ary Setyawan; Arif Budiarto
Journal of Engineering and Technological Sciences Vol. 55 No. 5 (2023)
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.2023.55.5.3

Abstract

Rubberized thin surfacing hot mix asphalt (RTSHMA) is a type of flexible pavement that is currently being developed. It can provide the same good performance as asphalt concrete–wearing course (AC-WC). Based on previous research, the use of crumb rubber in the asphalt mixture can provide several advantages, such as increasing the flexibility of the mix so that the pavement is more resistant to cracking. Based on research showing the advantages of rubberized asphalt, the idea emerged to apply it in the field, namely on the Palur–Sragen City Boundary section as wearing course. The method of analysis in this study was modeling the pavement structure with the KENPAVE and BISAR 3.0 programs. The analysis results showed that the AC-WC model and RTSHMA model have the same good performance because both of them have a service life of more than twenty years, which is the standard for flexible pavements. However, RTSHMA has an advantage, i.e., the thickness layer is 25% thinner than AC-WC’s. With a thinner layer than AC-WC but the same good performance, RTSHMA is worth considering as an alternative pavement, especially for overlays.

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