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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 10 Documents
 1 
Search results for , issue "Vol. 57 No. 1 (2025): February" : 10 Documents clear
Perfluorooctanesulfonic acid Sorption onto Polyethylene Microplastics: A Simulation-Driven Response Surface Optimization via Central Composite Design Enyoh, Christian; Wang, Qingyue; Ovuoraye, Prosper Eguono; Lu, Senlin; Egbosiuba, Titus
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.2

Abstract

This study demonstrates the application of response surface modeling within a Central Composite Design (CCD) to optimize the sorption processes of perfluorooctanesulfonic acid (PFOS) onto polyethylene microplastics (PE MPs), using simulation-based data from Grand Canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. The investigation intricately analyzes the complex interactions governing sorption phenomena (i.e. temperature and PFOS loading counts) with responses such as sorption energy, sorption density, and binding energy, employing RSM within a CCD framework. The optimization process established that the PE MPs sorption energy and sorption density were significantly dependent on PFOS loading counts in an aqueous environment. The result provides that at elevated temperature binding energy of PE MPs to Per- and polyfluoroalkyl substances was also dependent on PFOS loading counts due to associated low sensitivity temperature in the system. Optimal conditions are unveiled, enhancing sorption energy by -181.89 Kcal/mol, binding energy by -161.02 Kcal/mol, and sorption density by 1.42 g/cm³. The interaction of temperature and PFOS loading count is thoroughly examined, revealing their respective influences on sorption dynamics. These findings significantly advance our comprehension of PFOS sorption processes, fostering improved strategies for environmental remediation involving microplastic-driven sorption phenomena.
Satellite-Observed Monthly Variability of Sea Surface Chlorophyll-a Concentration: A Case Study in East Malaysia Kemarau, Ricky Anak; Eboy, Oliver Valentine; Sakawi, Zaini; Suab, Stanley Anak; Noor, Noorashikin Md
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): February
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.2025.57.1.1

Abstract

Monsoon variability plays a pivotal role in Malaysia's economy, yet research has overlooked its impact on chlorophyll-a distribution in the South China Sea. Our study addresses this gap, focusing on the monsoon's influence on chlorophyll-a levels in Malaysian waters, enhancing the understanding of regional marine ecosystems and their economic significance. The objective of this research is to examine the Northeast Monsoon (NEM) and Southwest Monsoon (SWM) influence on the variability of chlorophyll-a concentration distribution and its relation to the total number of fish landings in East Malaysia in the year 2019. To achieve this goal, MODIS data was utilized. Literature reviews have indicated that remote sensing wavelength reflectances at 443 and 555 nanometers were also employed to assess phytoplankton biomass and suspended sediment concentrations. An increase in the phytoplankton absorption coefficient at 443 nanometers, coupled with a higher backscattering constant for dissolved and detrital material, correlates with elevated phytoplankton biomass and suspended sediment concentrations. The investigation revealed significant variability in chlorophyll-a concentrations across monsoon seasons, with values peaking at 36.5 mg mˉ³ during the SWM, which contrasts markedly with the NEM. This influence of suspended sediment and organic matter may introduce bias to chlorophyll-a concentration measurement. Accordingly, an increase in the phytoplankton absorption constant at 443 nanometers, coupled with a higher backscattering coefficient for dissolved and detrital material, correlates with elevated phytoplankton biomass and suspended sediment concentrations. The investigation revealed significant variability in chlorophyll-a concentrations across monsoon seasons, with values peaking at 36.5 mg mˉ³ during the SWM, which contrasts markedly with the NEM. This variability underscores the profound impact of monsoon dynamics on chlorophyll-a distribution in East Malaysia, influencing both marine biomass and fishery yields. These findings suggest that different monsoon seasons lead to varying total fish landings in East Malaysia. Established on the observed differences in chlorophyll-a dispersion, remote sensing technology explains higher fish catches during the SWM than the NEM. This information is vital for fishers, as it aids in optimizing their operation and reducing overall costs.
Experimental Investigation and Prediction of Combustion Parameters using Machine Learning in Ethanol - Gasoline Blended Engines Sonawane, Shailesh; Sekhar, Ravi; Warke, Arundhati; Thipse, Sukrut; Rairikar, Sandeep; Varma, Chetan
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.3

Abstract

Alternative fuels play an important role in eco-friendly transport solutions. Wider adoption of alternative blended fuels in automobiles is dependent on a better understanding of the blended fuel engine characteristics. This paper presents an experimental investigation on the part load combustion characteristics of a multi cylinder spark ignition (SI) engine fueled by E0 and E10 ethanol blends. Full factorial Taguchi experimental design was employed to include multi-level engine speed (rpm) and load (throttle %) variations. High-speed data acquisition was used to record combustion parameters viz. maximum pressure (Pmax), indicative mean effective pressure (IMEP), start of combustion (SOC), mass burn fraction (MBF) and burn duration (Brn_drn) over 300 combustion cycles for each experimental run. Grey Relational Analysis (GRA) was used to determine the optimum best and worst engine operating conditions based on Pmax, IMEP, MBF and Brn_drn. Cycle-to-cycle variations of Pmax were also examined in detail to identify the worst engine operating condition. Random Forest machine learning algorithm was employed to accurately model Pmax and SOC in terms of the engine part load operating conditions. This model can be used to predict Pmax and SOC characteristics of an E0/E10 fueled SI engine under different operating conditions, eliminating the need for extensive testing
Mechanical Behavior of Concrete Reinforced with Natural Palm and Mango Fibers Flores Nicolás, Alejandro; Flores Nicolás, Mario; Menchaca Campos, Elsa Carmina; Uruchurtu Chavarín, Jorge
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.4

Abstract

The search for new natural materials as reinforcement in concrete has increased as an economic and ecological alternative. The purpose of this work is to study the behavior of natural mango (mangifera indica) and palm fibers without treatment, incorporated into concrete to improve its mechanical properties. The physical properties of the coarse (gravel) and fine (sand) aggregates were analyzed, as well as the physical and mechanical characteristics of the fibers used in this research. Concrete mixtures were prepared incorporating 0.2% and 0.4% fiber content with respect to the weight of fine aggregate and a fiber length of 10 and 30 mm respectively. The experimental results showed that all the fibers used in different concentrations decreased the workability and air content of the concrete paste, consequently, the porosity had a downward trend. Short mango fibers at 0.4% concentration and palm fiber at 0.2% increase the compressive strength by 12% compared to the control sample.
Performance Analysis of Radiation Detection Devices in Elevated Natural Radiation Zones: A Case Study of Mamuju Regency, West Sulawesi Indonesia Abdullah, Adi Rahmansyah Amir; Permana, Sidik; Srigutomo, Wahyu; Maulana, Alan; Seno, Haryo; Purnama, Dikdik Sidik; Tursinah, Rasito; Humolungo, Ismail; Zulfahmi, Zulfahmi
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.8

Abstract

Three radiation detection tools were employed to assess natural radiation levels in Mamuju Regency, West Sulawesi, Indonesia. These tools comprised the NaI(Tl) Scintillator, the Geiger Muller Counter (GMC), and the Electronic Personal Dosimeter (EPD). The NaI(Tl) Scintillator and GMC measured ambient dose equivalent (H*(10)), while the EPD exclusively gauged personal dose equivalent (Hp(10)). A total of 75 measuring points were designated for assessment. Results from H*(10) measurements indicated that the GMC recorded an average H*(10) 41% higher than that of the NaI(Tl) Scintillator, with specific rates of 0.769 µSv/h and 0.457 µSv/h, respectively. Both instruments exhibited proficiency in detecting elevated levels of radiation. Discrepancies in the outcomes were attributed to differences in detector type and efficiency. The GMC, equipped with an energy-compensated detector, demonstrated enhanced efficiency compared to the NaI(Tl) Scintillator, particularly when subjected to high energy flux radiation. Anomalies emerged in the Hp(10) measurements, which surpassed the H*(10) measurements. This difference is due to the EPD's use of a conventional GM detector, which is capable of detecting gamma, beta, and X-ray radiation
The Effect of Chain Tacticity on the Thermal Conductivity of Isotactic and Syndiotactic Polystyrene Taha, Dalmn Y.; Ahmed, Israa Z.; Mohammed, Tawfeeq
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.7

Abstract

This study looks into the influence of tacticity on the heat conduction through isotactic and syndiotactic polystyrene. The experimental work includes the collection of five different batches of polystyrene pellets with different tacticity. The molecular weight, isotacticity index and coefficient of thermal conductance were measured using gel permeation chromatography (GPC), nuclear magnetic resonance (NMR) and thermal conductivity apparatus, respectively. The results have indicated that there are relationships between these parameters for certain conditions. The obtained data show that isotacticity index enhanced by increasing the molecular weight of polystyrene. Subsequently, the isotacticity index affected the value of thermal conductivity of polystyrene. It was observed that the decrease of isotacticity in the syndiotactic polystyrene leads to reduce its thermal conductivity by 15-20%. But, the thermal conductivity of syndiotactic polystyrene is still higher than that of isotactic mode by 30-40% in average. The NMR analysis shows that the presence of random phenyl groups in the polymer decreases its isotacticity
Innovative Approach to Graphene Film Synthesis: Factorial Design in PECVD Experiments Pitjamit, Siwasit; Vichiansan, Norrapon; Leksakul, Komgrit
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.6

Abstract

Graphene, a two-dimensional carbon allotrope, has garnered significant interest due to its exceptional properties and diverse applications. This study investigates the optimization of graphene synthesis parameters using plasma-enhanced chemical vapor deposition (PECVD) to enhance film properties and broaden their application potentials. Using a comprehensive factorial design approach, factors including electric power (ranging from 60 to 100 W), the acetylene-to-hydrogen ratio (ranging from 30:70 to 50:50), and discharge time (ranging from 10 to 30 minutes) were systematically varied, and film thickness and the D/G ratio served as response variables. The experimental results revealed the significant effects of these parameters on film thickness, with optimal conditions identified as an electric power of 100 W, an acetylene-to-hydrogen ratio of 50:50, and a discharge time of 10 min. The average film thickness ranged from 41.51 to 253.80 nm. Morphological and structural analyses using atomic force microscopy and Raman spectroscopy elucidated the impact of synthesis parameters on film characteristics, with the D/G ratio varying from 0.75 to 1.8, indicating the degree of graphitization and defect density. Furthermore, surface properties and wettability were assessed using contact angle measurements, providing insights into surface interactions crucial for various applications. This study culminates in discussions on the implications for graphene synthesis optimization and its potential applications across diverse fields. Overall, this research contributes to advancing the understanding of graphene synthesis methodologies and underscores its significance in driving technological innovations.
Quantitative Analysis of Gravity Currents Using the Light Attenuation Technique Tjung, Ezra Yoanes Setiasabda; Kikkert, Gustaaf Adriaan
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.9

Abstract

It is well known that when two fluids with different specific densities are put adjacent to each other, there is an unbalanced horizontal density gradient that results in the adjustment process to achieve equilibrium, so that the less dense fluid finds its way atop the denser fluid. The purpose of this study is to employ light attenuation technique to obtain quantitative data in investigating the mentioned phenomenon. Specifically, the gravity current experiment models what is commonly found in estuaries, where there is an unbalanced density gradient due to the different densities of saltwater and fresh water. The use of light attenuation technique enables a more accurate quantitative data collection and thus enables a more rigorous definition of the location of the nose and the thickness of the head to be applied during the analysis of experimental data. It also allows for investigating the mixing characteristics of the two fluids in the highly turbulent layer immediately behind the current head process such as the velocity and the thickness of the shear layer
Investigation of Reaction Dynamics of Methane Reforming on Nickel Clusters Using Molecular Dynamics Simulations Arifin, Rizal; Muzakki, Fikrun Najib; Winardi, Yoyok; Widaningrum, Ida; Zulkarnain, Zulkarnain; Abdurrouf, Abdurrouf; Johari, Norhasnidawani; Lee, Vannajan Sanghiran; Darminto, Darminto
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.5

Abstract

This study employed molecular dynamics simulations utilizing the ReaxFF force field to elucidate the mechanisms underlying methane decomposition and hydrogen generation on nickel clusters (Ni37, Ni55, and Ni80). The transformation of methane into valuable products, including carbon species and hydrogen molecules, is of considerable significance owing to the abundance of methane and its potential role as an atmospheric pollutant. The findings suggest that Ni37 clusters had the highest initial reactivity, although they deactivated swiftly; conversely, Ni55 and Ni80 exhibited more consistent reaction rates. The highest efficiency of hydrogen production per unit surface area was displayed by Ni55 clusters within 100,000 fs, demonstrating a balance between reactivity and stability. Methane dissociation on the Ni55 clusters occurred in multiple stages. Two distinct mechanisms for hydrogen formation were identified: simultaneous dissociation from methane and migration and the combination of hydrogen atoms on the cluster surface. Ni55 showed a substantially lower activation energy for methane dissociation at 0.5 eV than bulk nickel, suggesting a higher degree of reactivity. Conversely, the activation energy for hydrogen formation was 1.1 eV. These results highlight the potential of the Ni55 clusters as effective catalysts for hydrogen production and methane conversion
Geometrically Complex, Relatively Weak, and Subcritically Stressed Lembang Fault May Lead to a Magnitude 7.0 Earthquake Palgunadi, Kadek Hendrawan; Simanjuntak, Andrean Vesalius Hasiholan; Ry, Rexha Verdhora; Daryono, Mudrik Rahmawan; Widiyantoro, Sri; Warnana, Dwa Desa; Triahandini, Agnis; Syaifuddin, Firman; Ahmadiyah, Adhatus Solichah; Sirait, Anne Meylani Magdalena; Suryanto, Wiwit
Journal of Engineering and Technological Sciences Vol. 57 No. 1 (2025): Vol. 57 No. 1 (2025): February
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.2025.57.1.10

Abstract

The Lembang Fault is one of the major faults in the province of West Java, approximately 10 km north of its capital, Bandung, a city inhabited by more than 2 million people. The fault exhibits distinct geometrical characteristics in its 29 km length, transitioning from normal, strike-slip, to vertical faulting mechanisms. Two studies have evidence of a normal fault with a dip direction to the north and a thrust fault with a dip direction to the south. Despite the lack of significant recorded earthquakes, the Lembang Fault is active and poses a high seismic hazard to the surrounding region. Previous deformation studies estimate that the fault could produce earthquakes of magnitude 6.7 to 7.0, though these estimates do not account for the fault's unique geometry, which includes bends at both its eastern and western ends. This geometrical complexity can significantly affect slip distribution, potentially leading to over- or underestimating earthquake magnitude. In this study, we assess the earthquake potential of the Lembang Fault using 3D dynamic rupture simulations that incorporate the fault's geometrical complexity, 3D velocity structure, and plastic deformation. Our simulations indicate that the fault's complex geometry enhances rupture slip to the east while halting it to the west, resulting in rupture along 80% of the fault's total length. However, according to our model, a self-sustained runaway rupture scenario occurs only if the fault is characterized by relatively weak apparent strength, subcritical stress, and overpressurization. This worst-case scenario could result in a magnitude 7.0 earthquake, posing a significant threat to the densely populated nearby city. Therefore, our findings have crucial implications for seismic hazard assessment around the Lembang Fault.

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