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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
 105   106   107   108   109 
Comparison of Surface Characteristics of Medical-grade 316L Stainless Steel Processed by Sand-blasting, Slag Ball-blasting and Shot-blasting Treatments Budi Arifvianto; Muslim Mahardika; Urip Agus Salim; Suyitno Suyitno
Journal of Engineering and Technological Sciences Vol. 52 No. 1 (2020)
Publisher : Institute 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.2020.52.1.1

Abstract

In this research, a comparative study was carried out to examine the surface characteristics of medical-grade 316L stainless steel after blasting treatments by using angular silica particles, spherical slag balls and spherical metallic shot. The surface roughness, morphology, elemental composition and microhardness distribution of the stainless steel were determined and the possible mechanisms in the evolution of the surface characteristics of the steel exposed to the blasting treatments were established. The results showed that all the blasting treatments conducted in this research increased the roughness and hardness of the steel surface. In this case, the roughest stainless steel surface was achieved by the slag ball-blasting treatment, but the stainless steel with the hardest surface and the thickest hard subsurface layer was obtained by the shot-blasting treatment. On the basis of the findings in this research it can be concluded that the physical properties and surface morphology of particles or shot used in the blasting treatment are critical parameters in determining the surface characteristics of blasted stainless steel.
Solvent Extraction Optimization of Chlorophyll Dye from Conocarpus Lancifolius Leaves Nawras Jameel Jassim
Journal of Engineering and Technological Sciences Vol. 52 No. 1 (2020)
Publisher : Institute 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.2020.52.1.2

Abstract

Recently, the green food industry has started using chlorophyll dye as a healthy and safe color additive for food and beverages. In this study, a conventional extraction technique was used to extract chlorophyll dye from Conocarpus lancifolius leaves, using 80% acetone as solvent. Taguchi's L25 orthogonal array was utilized to optimize the extraction parameters with total chlorophyll dye yield as the response. The optimum extraction conditions were 75 minutes of extraction time, 33.5 °C extraction temperature and a 118 ml/g solvent to raw leaves ratio. Analysis of variance using Minitab18 was conducted to identify the most significant extraction parameters and available interactions. It was found that the chlorophyll dye yield from Conocarpus lancifolius leaves is mostly dependent on extraction time, followed by mixing ratio and temperature. The analysis showed a large interaction between the extraction parameters studied. The experimental chlorophyll dye yield was in close agreement with the predicted model. The adequacy of the predicted model was confirmed by an experiment conducted under the optimal conditions, given a 3.9% error percentage.
Preparation and Characterization of Biopolymer Electrolyte Membranes Based on LiClO4-Complexed Methyl Cellulose as Lithium-ion Battery Separator Sun Theo Constan Lotebulo Ndruru; Deana Wahyuningrum; Bunbun Bundjali; I Made Arcana
Journal of Engineering and Technological Sciences Vol. 52 No. 1 (2020)
Publisher : Institute 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.2020.52.1.3

Abstract

The polymer electrolyte membrane is a main component of lithium-ion batteries (LiBs), serving as separator and electrolyte. In this work, we prepared biopolymer electrolyte (BPE) membranes of lithium perchlorate (LiClO4)-complexed methyl cellulose (MC). Methyl cellulose (MC), a cellulose derivative, has attractive properties for use as biopolymer electrolyte. The bulkier anion size of lithium salt (LiClO4) significantly enhances the performance of biopolymer electrolyte (BPE) membranes. The fabricated biopolymer electrolyte (BPE) membranes were characterized by FTIR, EIS, tensile tester, XRD and TGA. Biopolymer electrolyte membranes with various weight percentages of LiClO4 salt (0%, 5%, 10%, 15%, and 20%) were prepared using a simple solution casting technique. Incorporation of 10% weight of LiClO4 into the MC-based host polymer was selected as optimum condition, because this yielded good conductivity (3.66 x 10-5 S cm-1), good mechanical properties (tensile strength 35.97 MPa and elongation at break 14.47%), good thermal stability (208.4 to 338.2 °C) as well as ease of preparation and low cost of production. Based on its characteristics it can be stated that the 10% LiClO4-complexed MC membrane meets the requirements as a candidate separator for lithium-ion battery application.
Reconnaissance on Liquefaction-induced Flow Failure Caused by the 2018 Mw 7.5 Sulawesi Earthquake, Palu, Indonesia Risqi Faris Hidayat; Takashi Kiyota; Naoto Tada; Jun Hayakawa; Hasbullah Nawir
Journal of Engineering and Technological Sciences Vol. 52 No. 1 (2020)
Publisher : Institute 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.2020.52.1.4

Abstract

The Mw 7.5 Sulawesi Earthquake 2018 was a catastrophic disaster that resulted in large numbers of casualties. This study aimed to investigate the damages of liquefaction-induced-flow failure in three areas in Palu city, i.e. Petobo, Balaroa, and Jono Oge. It was found that this flow failure occurred on a large scale at a very gentle ground inclination, ranging from 1 to 3%. In order to gain an understanding of the soil conditions in these specific locations, Portable Dynamic Cone Penetration Tests were conducted in Petobo. The results showed that the soil layers in the affected area were in a loose state compared to the non-affected areas. Furthermore, some spots of freshwater inundation were recognized in Petobo and Balaroa, even two weeks after the disaster. Based on this evidence, a mechanism of liquefaction-induced-flow failure caused by a confined aquifer is proposed.
Comparison of Formulation Methods to Produce Nano-Chitosan as Inhibitor Agent for Bacterial Growth Prihati Sih Nugraheni; Alexander H. Soeriyadi; Ustadi Ustadi; Wahyudi Budi Sediawan; Wiratni Budhijanto
Journal of Engineering and Technological Sciences Vol. 51 No. 3 (2019)
Publisher : Institute 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.2019.51.3.9

Abstract

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.
Torrefaction of Rubberwood Waste: The Effects of Particle Size, Temperature & Residence Time Winny Wulandari; Nursayyidah Ainun Jahsy; Adrian Hartanto Tandias; Jenny Rizkiana; Inga Shaffira Rubani; Wibawa Hendra Saputera; Dwiwahju Sasongko
Journal of Engineering and Technological Sciences Vol. 52 No. 2 (2020)
Publisher : Institute 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.2020.52.2.1

Abstract

Agriculture waste has created massive challenges over the last few decades and yet also opportunities. This work aimed to produce high-quality biochar from rubberwood waste with calorific properties close to subbituminous coal. Using a tubular vertical reactor, the effects of rubberwood particle size (wood chips and shredded wood), torrefaction temperature (220, 260, and 300 °C), and residence time (30, 60, and 90 minutes) on the quality of torrefied rubberwood were studied. The results showed that the mass loss of the rubberwood increased as the temperature increased. Also, the particle size and residence time increased due to excessive devolatilization. A higher fixed-carbon content and calorific value as well as lower moisture and volatile-matter content were achieved by increasing the torrefaction temperature and residence time in comparison to the untreated sample (raw rubberwood). The highest fixed-carbon content and calorific value were found to be 56.7% and 6313 kcal/kg, respectively, for the wood chip particles that were torrefied at 300 °C for 60 minutes. Based on the Van Krevelen diagram, torrefaction of woodchip rubberwood at 300 °C with a residence time of 60 minutes demonstrated the optimum condition to generate a product with properties that are close to those of subbituminous rank coal.
Theoretical Beam Hardening Correction for Industrial X-ray Computed Tomography Osama Mhmood Hamed Ahmed; YuShou Song; Xie Zhaoyang
Journal of Engineering and Technological Sciences Vol. 51 No. 6 (2019)
Publisher : Institute 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.2019.51.6.9

Abstract

Beam hardening is a significant artifact that comes from the polychromatic nature of the X-ray source in computed tomography. It appears because the object tends to absorb more low-energy photons within the beam, which leads to a nonlinear relationship between attenuation and material thickness. As a result, the reconstructed image is spoiled. This work articulates an approach to promoting the correction of MeV X-ray beam hardening. In order to calculate the attenuation of the polychromatic beam, the following terms were evaluated: the energy spectra S(E) for sets of X-ray spectra with a maximum energy of 2, 4, 6 and 9 MeV were simulated using the Geant4 toolkit; the counting efficiency λ(E) was estimated based on the Lifton method; and the attenuation coefficient µ(E) was taken from the NIST database. The non-linear relationship between the attenuation and the thickness of iron was investigated. The beam hardening for each energy set was successfully corrected by polynomial fitting, transforming the polychromatic attenuation data into equivalent monochromatic data. The corrected attenuation was used to estimate the penetration capability of the X-ray source and produced a result that was consistent with what has been reported in the literature.
Layer Stripping in Magnetotellurics (MT) for Enhancement of Resistivity Change Effect in Reservoir: Equivalence Analysis Hendra Grandis; W Warsa; Prihadi Sumintadireja
Journal of Engineering and Technological Sciences Vol. 52 No. 2 (2020)
Publisher : Institute 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.2020.52.2.9

Abstract

Magnetotellurics (MT) can be applied to monitor resistivity change at depth that is for example due to fluid injection in enhanced oil recovery or CO2 storage. The observed MT data changes at the surface may be insignificant, but the effect can be enhanced using the layer stripping method, i.e. calculating MT data changes that would be observed at depth based on data from the surface. Two well-known formulas for MT 1D forward modeling were reformulated to allow for calculation of the impedance at depth based on the impedance at the surface. We applied the layer stripping technique to synthetic data associated with models that were representative of a likely CO2 storage site. We also used an equivalent model and the Monte Carlo approach to estimate the sensitivity of the method to cope with the uncertainty of the host model and the input data. The layer stripping calculation has the greatest uncertainty at short periods, where the real and imaginary parts of the complex impedance tend to be equal, i.e. an homogeneous medium response. The layer stripping technique should be used with great caution based on a relatively precise 1D host model.
Study on the Influence of Toilet Siphon Pipe Shape on Flushing Performance Xiaole Ge; Hongfeng Wang; Zhanfu Li; Shengrong Liu; Xin Tong; Jiafei Pu; Qi Dong
Journal of Engineering and Technological Sciences Vol. 52 No. 6 (2020)
Publisher : Institute 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.2020.52.6.1

Abstract

The goal of this work was to explore the influence of toilet siphon pipe shape on flushing performance. The flushing processes of a toilet under different shape parameters were simulated by using computational fluid dynamics (CFD) with a volume of fluid (VOF) multiphase model. The effects of siphon pipe shape on flushing performance were analyzed in detail. The interpretation of the simulation results was experimentally validated. The results reveal that a toilet may obtain good flushing performance under one single shape parameter when the climbing angle, the arc width, the arc height, the pipe diameter, the climbing width, and the climbing height are about 48°, 45 mm, 210 mm, 50 mm, 90 mm and 30 mm, respectively. With the increase of the siphon pipe diameter, the toilet flushing performance peaks in the range between 50 and 53 mm rather than continuing to improve. In order to reasonably evaluate the flushing effect of the toilet, all flow parameters on a characteristic cross section of the siphon pipe, including the average velocity, the average pressure and the average mass flow rate, should be comprehensively considered instead of one single parameter. The findings of this study provide a reference for the pipe shape design of toilets.
Seismic Performance of RC Hollow Rectangular Bridge Piers Retrofitted by Concrete Jacketing Considering the Initial Load and Interface Slip Made Suarjana; Daniel Dixon Octora; Muhammad Riyansyah
Journal of Engineering and Technological Sciences Vol. 52 No. 3 (2020)
Publisher : Institute 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.2020.52.3.4

Abstract

In design practice, the assumptions that are used in retrofitting concrete structural elements often ignore the initial load and the interface slip on the contact surfaces between the old and the new concrete. The concrete structural elements that are loaded by the existing gravity load cause initial strain on the existing cross-section before jacketing is applied, while the interface does not act in a fully composite manner. In this study, a seismic performance evaluation using pushover analysis was performed of a damaged reinforced concrete bridge pier retrofitted with concrete jacketing, where the plastic hinge of the retrofitted elements was modeled by considering both parameters. The results showed that concrete jacketing could increase the capacity of the bridge structure. It was also found from the numerical result that the performance level of the bridge considering the initial load compared to the monolithic approach gave the same result since the initial load did not significantly affect the cross-sectional ultimate capacity. The difference between the ultimate capacity values computed by the two models was less than 7%. It was also shown that the interface slip had a significant effect with a slip coefficient smaller than 0.5.

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