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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. 6 (2024)" : 11 Documents clear
Optimization of Ultrasonic and Microbubble Disinfection for Escherichia coli and Staphylococcus aureus: Experimental Design and Effectiveness Evaluation Pitjamit, Siwasit; Vichiansan, Norrapon; Leksakul, Komgrit; Boonyawan, Dheerawan
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.6

Abstract

This study investigated the synergistic application of ultrasonic (UL) and microbubble (MB) technologies for the disinfection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Optimal conditions for both techniques were determined through a comprehensive experimental design, resulting in an effective disinfection rate of 100% as assessed by the ten-fold dilution spread plate count method. The study evaluated three key parameters of the UL/MB system, i.e., UL duration time, MB duration time, and gas flow rate within the ranges of 30-60 sec, 30-60 sec, and 15-30 ml/min, respectively. A 2k full factorial design with three replications, five center points, and blocking was employed for robust statistical analysis. Based on the empirical data and rigorous statistical examination, the optimal conditions for achieving sterilization of E. coli and S. aureus were determined as 30 sec UL duration, 30 sec MB duration, and 30 ml/min gas flow rate; and 60 sec UL duration, 60 sec MB duration, and 15 ml/min gas flow rate, respectively. Utilizing these optimal conditions, the disinfection efficacy was assessed, revealing an inhibition rate of 54% for E. coli and an inhibition rate of 19% for S. aureus, with consistent improvement observed across the three replication trials. These findings underscore the potential of UL/MB technology as an effective disinfection strategy against common bacterial pathogens
Improved Risk Assessment of TBM Tunneling Collapse Based on Nonlinear-Cloud Model Wang, Longjiang; Xu, Tian; Zong, Dachao; Han, Qiang; Zhao, Yongjin; Song, Zhanping; Zhang, Yongli
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.9

Abstract

An innovative nonlinear enhancement technique that integrates the cloud model with Fuzzy Analytic Hierarchy Process (FAHP) is presented in this study. For the first time, this paper introduces TBM tunnelling parameters as evaluation indicators for tunnel construction collapse risk. Precise risk level thresholds are set for each indicator, establishing a comprehensive TBM construction collapse risk assessment system. Within this system, the cloud model is applied to accurately depict membership degrees, transcending the limitations of traditional reliance on functional formulas. Furthermore, the AHP is utilized to precisely calculate the weight vectors of the assessment indicators. Most significantly, this study introduces a nonlinear operator to achieve an efficient integration of the weight vectors with the fuzzy relation matrix. Based on the principle of maximum membership degree, the ultimate collapse risk level for TBM construction is determined. This method overcomes the shortcomings of traditional FAHP, which neglects the randomness in calculating membership degrees and the potential dilution of the influence of key risk factors when using linear operators in comprehensive risk assessment. The model was applied and validated in a hydraulic tunnel construction project, demonstrating its innovation and reliability, thus providing new theoretical foundations and technical support for the field of tunnel construction risk assessment.
Role of Deagglomeration in Particle Size and Antibiofilm Activity of ZnO Nanoparticles Synthesized with Averrhoa bilimbi Extract Wonoputri, Vita; Samadhi, Tjokorde Walmiki; Khairunnisa, Shafira; Rahayu, Eka
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.5

Abstract

Averrhoa bilimbi fruit extract was utilized as a reducing and capping agent in the biosynthesis of zinc oxide nanoparticles, with an emphasis on the effects of in-situ deagglomeration on physical properties and antibiofilm activity against Escherichia coli. The study explored various biosynthesis parameters, namely deagglomeration method (physical vs chemical), temperature (30, 60 ℃), and zinc precursor-to-extract volumetric ratio (0.5 and 2). High purity crystalline ZnO nanoparticles were obtained by calcining biosynthesis precipitates at 375  ℃. The resulting particles consisted of the wurtzite ZnO phase, with diameters ranging from 18 to 30 nm. The hydrodynamic mean particle diameters were 1.0 to 3.5 µm, suggesting the formation of soft agglomerates. Physical deagglomeration was more effective at higher temperatures, while chemical deagglomeration was more efficient at lower temperatures, owing to the interaction between the deagglomeration method and biosynthesis temperature. The biosynthesized ZnO nanoparticles exhibited good antibiofilm activity, achieving a 61% reduction in biofilm population at 50 ppm ZnO, which increased to 78% at a dose of 200 ppm. This activity was improved by lower biosynthesis temperature and precursor:extract ratio, likely due to the preservation of bioactive molecules. The results demonstrate the potential of biosynthesized ZnO nanoparticles as antibiofilm agent, offering enhanced effectiveness compared to commercial ZnO nanoparticles
Interpreting Arc and Line Shapes in the Fault Ruptures of the 2016 Mw7.8 Kaikoura, New Zealand and the 2023 Mw7.8 and Mw7.6 East Anatolian Fault, Turkey-Syria Earthquakes: A Theoretical Approach Daryono, Mudrik Rahmawan; de Gelder, Gino; Patria, Adi
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.1

Abstract

This study examined the arc and line shapes produced in the fault ruptures of the 2016 Mw7.8 Kaikoura earthquake in New Zealand and the 2023 Mw7.8 and Mw7.6 East Anatolian Fault earthquakes in Turkey-Syria. Theoretical fault mechanisms and physical laws of movement were used to interpret the conceptual geometry of the arc and line shapes, and kinematics force movement. Using computer-aided design (CAD) on the Universal Transverse Mercator (UTM) metric projection, this paper presents earthquake parameters defining the fault geometry, including straight lines and arc shapes with specific measurements such as radius, length, angles, and normal/perpendicular vectors. Comparative analysis revealed distinctions between the two seismic events. Specifically, the Kaikoura earthquake exhibited a smaller normal vector compared to the Turkey-Syria earthquakes. Further interpretation uncovered that the Kaikoura earthquake resulted from pressure exerted by the radius arc vector from both the south-east and north-west, aligning with the continuation of the north-easternmost fault rupture. This suggests that the primary fault vector aligns with the fault trend. In contrast, the Turkey-Syria earthquakes displayed two independent circuit systems. The first event in the Turkiye-Syria rupture underwent an orientation change or bending of about 137 degrees (from N24oE to N68oE). The normal vector of the second earthquake originated from the bending angle of the first earthquake, close to its hypocenter. The rupture of the Kaikoura earthquake followed a lineament orientation of N47oE, forming an approximately 10-km wide corridor, comprising both straight lines and arc shapes.
Properties of Hydrochar Derived from Arabica Coffee Agro-Industry Residues under Wet Torrefaction Method Shalihah, Nyakty; Setiawan, Adi; Muhammad, Muhammad; Riskina, Shafira
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.2

Abstract

This study utilized coffee cherry residues, which is an abundantly available source of biomass in Indonesia. One of the methods to utilize coffee plantation residues effectively is wet torrefaction. This method is well-known as a hydrothermal method, where the biomass conversion process uses liquid as a medium and reactant in the process. The objective of this work was to develop an effective procedure for converting coffee agro-waste into marketable products using hydrothermal technology. The information related to changes in physical and thermal properties were explored in this work. To achieve the research objectives, three main steps were performed, i.e., feedstock preparation, wet torrefaction, and hydrochar characterization. Two types of feedstocks were studied in this work, coffee parchment and coffee pulp. In the wet torrefaction process, each feedstock was treated using two types of solutions, i.e., distilled water and acetic acid, at different concentrations. The reaction was carried out in an autoclave with a pressure of 2 bar (g) and an operating temperature of 130 ℃ for 2 hours. The properties of the hydrochar products were then analyzed using various methods, including bomb calorimetry, SEM, density, TGA-DTG, and hydrophobicity analyses. Overall, the results indicated that the hydrochar produced under acetic acid solution had better characteristics compared to that treated under distilled water. In terms of fixed carbon content and calorific value, the values increased up to 25.3% and 4,603 kcal/kg, respectively. Enhanced hydrophobicity was only observed in the coffee parchment hydrochar, where the average time required to adsorb water was 146.6 s, which can be categorized as strongly hydrophobic.
Experimental Investigation of Ammonia/Oxygen/Argon Combustion: The Role of Equivalence Ratio and Nozzle Shape in a Constant Volume Combustion Chamber with Sub-chamber Mitsuhisa Ichiyanagi; Emir Yilmaz; Takuma Ohashi; Masato Sanno; Guansen Lin; Sebastian Gunawan; Henry Widjaja; Leon Jonathan; Gabriel Jeremy Gotama; Willyanto Anggono; Takashi Suzuki
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.3

Abstract

The global rise in carbon emissions presents a rising challenge for current and future generations. In the pursuit of zero carbon emissions, ammonia (NH3) has emerged as an attractive alternative energy source. Ammonia offers a carbon-free fuel option with a higher energy density than liquid hydrogen while maintaining ease of transport and storage. However, ammonia still has its drawbacks, such as a high autoignition temperature, slow burning velocity, and low heating value, that demand further investigation of its combustion characteristics. This experiment was done to study the effect of nozzle shape and equivalence ratio (ɸ) on the combustion of an ammonia/oxygen/argon mixture using a constant volume combustor equipped with a sub-chamber. The fuels were premixed for 10 minutes and conditioned to an initial pressure of 0.2 MPa and an initial mixture temperature of 423 K. The results show that the different nozzle shapes each have their advantages in terms of pressure and jet speed. Overall, the lean mixtures (ɸ0.6 and ɸ0.8) consistently performed better compared to the stoichiometric mixtures (ɸ1.0) in all categories investigated in this study. The round nozzle generates higher pressure, while the special shape nozzle enhances jet speed, highlighting trade-offs between the two.
Evaluation of Mechanical Properties of Warm-Mix Asphalt Mixtures Prepared with Sasobit and Zeolite Additives Wshyar M. Hasan; Rana A. Yousif; Saeid Hesami; Sady A. Tayh; Abbas F. Jasim; Hawkar H. Ibrahim
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.4

Abstract

This study aimed to evaluate the impact of different additive percentages on the mechanical properties and durability of warm-mix asphalt. Two types of additives, Sasobit as an organic additive and Zeolite as a water-based additive, along with bituminous foam, were used at 2%, 4%, and 6% levels in modified asphalt mixes. Rutting resistance, moisture susceptibility, and cracking resistance were assessed using semi-circular bending tests, dynamic creep tests, and indirect tensile strength tests, respectively. Additionally, a two-dimensional performance interaction diagram was developed. The results indicated that incorporating different percentages of Sasobit and Zeolite additives improved rutting and cracking resistance, respectively. Zeolite showed a positive impact on enhancing the resistance of the asphalt mixture against moisture susceptibility, while Sasobit had a negative effect. Moreover, the influence of these additives on mechanical performance intensified with increasing percentages. Notably, the mixture containing 6% Zeolite demonstrated the highest resistance to moisture susceptibility, while the mixture with 6% Sasobit showed the lowest. Furthermore, the performance interaction diagram results suggested that using 4% and 6% Zeolite along with 4% Sasobit is optimal for rutting and cracking resistance. Considering the degradation mechanisms of moisture susceptibility, rutting, and cracking, mixtures with 6% Zeolite and 4% Zeolite exhibited satisfactory performance against these factors.
Fatigue Evaluation of Steel Truss Arch Bridge Based on Traffic Load Simulation Using Weigh-in-Motion Data: Case Study of Rumpiang Bridge Rio Pramana; Ivan Sandi Darma
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.7

Abstract

The aim of this study was to evaluate the fatigue life of Rumpiang Bridge in Barito Kuala Regency, South Kalimantan, which features a 200-meter-long steel truss arch structure. Fatigue evaluation was performed by referencing the AASHTO Manual for Bridge Evaluation 2018 and the provisions in RSNI T-03-2005 and using the cumulative fatigue damage method. Actual traffic loads based on weigh-in-motion (WIM) data obtained from Prof. Dr. Ir. Sutami Road in Lebak Regency, Banten over a seven-day period were simulated using structural modeling in MIDAS Civil 2022. The results indicated that Rumpiang Bridge is susceptible to fatigue failure, due to a cross-girder element experiencing a maximum stress range of 171.30 MPa and an effective stress range of 75.31 MPa. The current accumulated fatigue damage is 0.179, with an estimated remaining fatigue life of 16 years. This relatively short remaining life is primarily due to 35.02% of vehicles recorded in the WIM data being overloaded. Implementation of traffic restrictions can extend the fatigue life of the bridge. After conducting various weight restriction scenarios, it was found that a restriction with a maximum vehicle load of 26 tons would result in a fatigue life that exceeds the design life of the bridge.
Utilization of Syngas as Co-firing Fuel for Carbonization of Arabica Coffee Pulp Rizqon Hasibuan; Adi Setiawan; Faisal Faisal
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.8

Abstract

Pyrolysis is a commonly used method to produce main products such as bio-char, bio-oil and syngas. However, the practical use of syngas as a fuel is currently constrained by suboptimal properties and the necessity for specialized storage. This study investigated the impact of using syngas directly as an additional fuel for heating the pyrolysis reactor on process parameters and the properties of the resulting bio-char products. The experiment was conducted using two process variations: (i) pyrolysis utilizing syngas as fuel for co-firing with LPG, and (ii) pyrolysis using only LPG as fuel. The variables observed during the testing included the consumption of LPG fuel, process time, heating rate, pyrolysis product yields, and the properties of the bio-char. Characterization of the bio-char was carried out through proximate analysis, bomb calorimetry, thermogravimetric and FTIR analysis. Based on the experimental results it can be concluded that co-firing is able to save on the use of LPG and reduce process time. In terms of product yield, there was no significant difference when syngas was co-fired with LPG. In terms of the properties of the bio-char product, syngas co-firing pyrolysis helps in reducing the moisture content, increasing the fixed carbon content, and also increasing the calorific value up to 26855 J/g.
Comparative Seismic Evaluation of Building Codes: A Case Study on Structural Performance and Safety Jovan Thierry Salim; Indra Djati Sidi
Journal of Engineering and Technological Sciences Vol. 56 No. 6 (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.2024.56.6.10

Abstract

The evolution of structural design standards, from empirical approaches to modern precision, has significantly impacted seismic evaluation and building safety. Indonesia’s adoption of seismic standards in 2002, aligned with global practices like ASCE, introduced notable shifts in seismic design philosophy. This study offers a novel comparison of the seismic performance of a forty-story office building in Jakarta designed under SNI 1726:2002 versus the updated SNI 1726:2019. The unique focus of this research lies in evaluating how the shift from a uniform risk philosophy to a uniform hazard philosophy, alongside changes in earthquake return periods, affects structural safety and performance criteria. A comprehensive seismic evaluation was conducted using both nonlinear static (pushover) and nonlinear time-history analyses (NLTHA), with performance criteria based on ASCE 41-17’s Life Safety and Collapse Prevention levels. By employing both methods, this study uniquely highlights discrepancies between traditional pushover analysis and the more rigorous NLTHA, a comparison rarely explored in the context of Indonesia’s seismic standards. The results revealed significant disparities between the two methods. While pushover analysis exposes potential beam failure under the Collapse Prevention criteria, the NLTHA results suggest a more resilient behavior, indicating that the structure may perform better under real seismic events. These findings emphasize the limitations of pushover analysis and underscore the importance of more detailed nonlinear time-history analyses in accurately assessing the seismic performance of buildings.

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