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Journal of Engineering and Technological Sciences

JETS
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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 â€“ 2012) Proceedings ITB on Engineering Science (2003 - 2007) Proceedings ITB (1961 - 2002)

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Articles 1,267 Documents

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Kinetics on Organic Removal by Aerobic Granular Sludge in Bubbled Airlift Continuous Reactor Yulianto, Andik; Zakiyya, Nida Maisa; Soewondo, Prayatni; Handajani, Marisa; Ariesyady, Herto Dwi
Journal of Engineering and Technological Sciences Vol 51, No 5 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

An assessment of aerobic granular sludge (AGS) in a bubbled airlift continuous reactor (BACR) was done to determine the AGS growth kinetics in the continuous reactor and the impact of varied hydraulic retention time (HRT) against the AGS structure. Sodium acetate was used as the sole carbon source with a 100:20 ratio of COD/N synthetic water. The system was operated at five variations of HRT, i.e. 12, 10, 8, 6, and 4 hours, with organic loading rate (OLR) ranging from 1.6 to 4.8 g COD/day in the BACR. Organic removal decreased from 73% to 52%, along with the increment of OLR, while HRT decreased from 12 hours to 4 hours. The kinetics of organic removal in the BACR were examined to get a better understanding of organic removal trends by AGS in a BACR. The models used for biomass growth analysis were the Monod, Contois, Grau second-order, and Stover-Kincannon kinetic models. This study showed that the best suited models for organic removal in BACR were the Grau second-order kinetic model with an a value of 0.1382 and a b value of 1.0776, and the Stover-Kincannon kinetic model with an Rmax of 5.8 g COD/L.day and a KB of 6.24 g COD/L.day.

Three-dimensional DC Resistivity Modeling using Galerkin Finite Element Method Composed by Tetrahedral Elements Srigutomo, Wahyu; Anwar, Hairil; Agustine, Eleonora; Mahardika, Harry
Journal of Engineering and Technological Sciences Vol 51, No 4 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Successful interpretation of DC resistivity data depends on the availability of a proper forward modeling scheme. In this study, a three-dimensional DC resistivity forward modeling scheme was developed using the finite element method. The finite element equations were obtained using a weakened form of the weighted-residual method called the Galerkin method. Discretization of the modeling domain was carried out by dividing it into smaller three-dimensional blocks and subdividing each block into five tetrahedral elements. A linear interpolation function was employed and elemental linear equations were set up, followed by formation of global matrix systems of equation and incorporation of proper boundary conditions. The conjugate gradient method was applied to solve the global system of equations, which in this study was proven to be more efficient than a direct solver, contributing to a 67% time reduction. Using a Wenner array configuration, comparison with theoretical calculation of the electric potential for a homogeneous model yielded a relative error of 3.66%. To confirm the applicability of this forward modeling scheme, apparent resistivity profiles for several basic three-dimensional subsurface resistivity models were compared with the analytical profiles, yielding an acceptable level of fitting.

Physical Model of Vertical Water Movement Inside a Soil-Column Apparatus for Infiltration Study with A Two-Way Orientation Approach Fajar, Reza Adhi; Handayani, Gunawan; Notosiswoyo, Sudarto; Widodo, Lilik Eko; Pamungkas, Tri Chandra
Journal of Engineering and Technological Sciences Vol 51, No 5 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

To improve the theory of Richard?s equation, studying infiltration under free-draining conditions at the ground surface is necessary. Verification is required to clarify the physical model of water movement. The aim of this study was to describe multistage measurements of both the wetting and the drying front scheme of one-dimensional infiltration at laboratory scale. A soil-column infiltration apparatus was built consisting of a double acrylic wall, a sensor set and a light bulb. Acrylic was chosen as the material for the wall to minimize possible heat conduction on the wall side, which was wrapped in double insulation to achieve adiabatic condition. The following three main sensors were used and controlled by a microcontroller: water-content, pressure and temperature sensors. Meanwhile, the light bulb at the top of the apparatus was set to non-isothermal condition. The instrument was successfully built to describe vertical water movement. Slight modifications were carried out to ensure more precise observation. This resulted in the initiating of new shape interpretation based on the water-ponding measurement to refine the simplified pattern that was introduced by the conventional Green-Ampt theory.

Comparison of Formulation Methods to Produce Nano-Chitosan as Inhibitor Agent for Bacterial Growth Nugraheni, Prihati Sih; Soeriyadi, Alexander H.; Ustadi, Ustadi; Sediawan, Wahyudi Budi; Budhijanto, Wiratni
Journal of Engineering and Technological Sciences Vol 51, No 3 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Chitosan is known as an antibacterial agent. The effective surface area ratio of chitosan can be increased by modification into nanoparticles. Nano-chitosan can be prepared with several simple methods, i.e. precipitation, ionic gelation, or the polyelectrolyte complex method. This study compared these three methods in terms of the targeted product characteristics, i.e. stability of the average nanoparticle size as well as the colloidal dispersion, and the antibacterial characteristics. All three methods resulted in nanoparticle formation, but in the precipitation method significant zeta potential reduction was observed due to the presence of negative ions from the alkali that neutralized the chitosan amine group. The ionic gelation method yielded higher zeta potential and higher inhibition of bacterial growth than those yielded by the polyelectrolyte complex method. Ionic gelation and the polyelectrolyte complex method resulted in much better colloidal dispersion stability than the precipitation method, where a significant particle size increase was observed after one week of storage. This result indicates that both ionic gelation and the polyelectrolyte complex method can be used for forming nano-chitosan for the purpose of food preservation. However, for fishery products it is advisable to use the polyelectrolyte complex method because the TPP usually used in ionic gelation is not allowed to be applied to fish.

Urban Energy Scenario: the Case of Kathmandu Valley Shrestha, Maria E. I.; Sartohadi, Junun; Ridwan, Mohammad Kholid; Hizbaron, Dyah R.
Journal of Engineering and Technological Sciences Vol 49, No 2 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2017.49.2.4

Rapid urbanization has made Kathmandu Valley one of the fastest growing metropolitan cities in South Asia, resulting in the need of additional facilities and infrastructure. The local energy crisis is one of the issues to be addressed. High dependence on imported fossil fuels and the sluggish development of hydropower for electricity generation despite abundant water resources are the major causes to be blamed for the energy crisis in Nepal. This study investigated possible strategies to be implemented in Kathmandu Valley to deal with the discrepancy between energy demand and supply. Several scenarios have been developed and analyzed, both quantitatively and qualitatively. The Comprehensive Scenario, which borrowed from all other developed scenarios, seems superior to the others. It reduces the energy demand by 32.36%, the GHG emission by 44.12%, and the social cost by 33.79%. This scenario implies that the Kathmandu Valley authority will support the installation of photovoltaic solar panels, the use of electric vehicles and electric cookers, and convert solid waste into energy. However, the EV Scenario (electric vehicles) is the one to be given priority in the implementation for its better performance than the other individual scenarios.

Development of a Respirable Dust Mitigation System for a High Longwall Face at Sihe Colliery in China â€“ a Case Study Wang, Junfeng; Tang, Yibo; Du, Hailong; Shang, Weiwei
Journal of Engineering and Technological Sciences Vol 49, No 4 (2017)
Publisher : ITB Journal Publisher, LPPM ITB

Dust is a major hazard in underground coal mines that threatens the work health and safety of coal miners. The dust issue becomes increasingly significant with the development of highly mechanized coal mining. This issue is particularly serious at the high longwall faces of the Sihe colliery in China as the concentration of dust, in particular respirable dust, at these faces far exceeds the regulatory dust limits. Field testing and computational fluid dynamics (CFD) simulations were conducted to understand the sources of dust generation and its dynamic movement in the #5301 longwall face of high-cutting height at the colliery. The investigation results showed that shearer generated dust was minimal during the coal cutting operation; that face spalling and chock movement were the main dust generating sources, causing significant contamination to the walkway; and that the majority of dust particles from the face (regardless of source) eventually disperse into the main gate, where the dust concentration was greater than 500 mg/m3. These findings were used to develop an effective coal dust mitigation system involving the installation of dust scrubbers, curtains, and venture and crescent sprays. The results of CFD modeling indicate that the dust concentration could be significantly reduced by adopting the new dust mitigation system.

Improving the Lifting Capacity of Drilled Cuttings Using Henna Leaf Extracts and Lignite in Bentonite Water-based Drilling Mud Oseh, Jeffrey Onuoma; Anam, Muhammad Noorul; Sidiqi, Adams Rasyid
Journal of Engineering and Technological Sciences Vol 51, No 3 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

One of the basic functions of drilling fluids is to transport drilled cuttings to the surface. Bentonite with low solids content is preferred in carrying out this task. However, a low amount of bentonite in the drilling mud is incapable of effective cuttings lifting and suspension. In this study, a new, green, low-cost henna leaf extract and lignite in bentonite water-based drilling mud was used to transport cuttings to the surface. The effects of three hole angles (0°, 45° and 90°) were examined at different cuttings size diameters (0.5 mm, 1.0 mm, 2.0 mm and 2.4 mm) for the mud systems. The average cuttings transport efficiencies were found to be in the following order: 52-94% for 0.5 mm diameter, 45-93% for 1.0 mm diameter, 38-90% for 2.0 mm diameter, and 33-83% for 2.4 mm diameter. Viscosity and hole angle are directly related to cuttings transport efficiency. A plastic viscosity of 16 cP and yield point of 12.5 lb/100ft² were the most effective mud properties for a 45° hole angle, which needs attention while preparing the drilling mud. Addition of henna and lignite can be used to improve the rheological and filtration properties of bentonite water-based drilling mud.

Drought Event Analysis and Projection of Future Precipitation Scenario in Abaya Chamo Sub-Basin, Ethiopia Gebeyehu, Ayele Elias; Chunju, Zhao; Yihong, Zhou; Wagasho, Negash
Journal of Engineering and Technological Sciences Vol 51, No 5 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Monthly observed and future precipitation magnitudes were subjected to statistical trend analysis to examine possible time series behavior. Future precipitation was downscaled from large-scale output through statistical downscaling. The observed and downscaled future precipitation was analyzed for drought events using the Standardized Precipitation Index (SPI) method. In the Abaya Chamo sub-basin, Ethiopia precipitation is explained by below average magnitudes in most of the low land area, characterized by moderate to extreme drought episodes. Nine drought events were discerned during the period of 1988 to 2015, i.e. once in three years, resulting in harvest failure and subsequent food insecurity. The NCEP-NCAR and CanESM2 model predictors were used to statistically downscale the precipitation data. The monthly observed and downscaled precipitation magnitudes were in good agreement. The RCP-2.6, RCP-4.5 and RCP-8.5 long-term future scenarios were computed to evaluate future drought patterns. The mean annual precipitation scenario decreased by 0.2% to 13.7%, 0.5% to 6.4% and 0.1% to 1.3% for the period from 2016 to 2040, 2050s and 2080s respectively. The increase in mean precipitation was projected to be 0.7% to 12.2%, 0.2% to 11.7% and 0.1% to 17.8% for the period from 2016 to 2040, 2050s and 2080s respectively. The present analysis may provide useful information associated to drought events to decision makers and can be used as a basis for future research in this area.

DBSA-Catalyzed Sewage Sludge Conversion into Biodiesel in a CSTR: RSM Optimization and RTD Study Jazie, Ali A.
Journal of Engineering and Technological Sciences Vol 51, No 4 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Sewage sludge from the primary stage of a wastewater treatment plant (WWTP) in Al-Diwaniyah City was direct-transesterified to biodiesel using dodecylbenzenesulfonic acid catalyst in a system with two continuously stirred tank reactors. The response surface and the central cube design methodologies were used to optimize the parameters affecting the biodiesel yield. The optimum conditions for the process in this study were found to be (residence time: 90 min; catalyst loading 8 wt%; methanol/oil ratio: 18; reaction temperature: 368.15 K). Under the optimum process conditions a biodiesel yield of 96.51% was obtained. The experimental residence time distribution (RTD) was calculated and compartment models were applied for the two-tank reactor system. In the CSTR, a dead zone of (10 liter) was estimated. The independent analysis of fatty acids in the sewage showed that the lipids consisted primarily of palmitic acid (C16:0 = 37.86), oleic acid (C18:1 cis-9 = 19.72) and stearic acid (C18:0 = 17.32), and the acid value was (2.44 mg KOH/g). The properties of the biodiesel produced were comparable with the ASTM D-6751-2 standard and the properties of mineral diesel.

Cover JETS Vol. 51 No. 1, 2019 Technological Sciences, Journal of Engineering and
Journal of Engineering and Technological Sciences Vol 51, No 1 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1423.315 KB)

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