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Journal of Engineering and Technological Sciences
ISSN : 23375779     EISSN : 23385502     DOI : -
Core Subject : 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)
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Articles 494 Documents
Development of Instant Microbial Starter for Production of Fermented Cassava Flour: Effect of Vacuum Drying Temperature, Carrier Media, and Storage Temperature Kresnowati, Made Tri Ari Penia; Bindar, Yazid; Rahmina, Fathya
Journal of Engineering and Technological Sciences Vol 50, No 6 (2018)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (141.447 KB) | DOI: 10.5614/j.eng.technol.sci.2018.50.6.6

Abstract

Cassava is an important crop for tropical countries such as Nigeria, Brazil, Thailand, and Indonesia. The potential utilization of cassava in the food industry can be enhanced by processing cassava into fermented cassava flour (fercaf), which has been shown to have a neutral color and aroma as well as low cyanogenic content. The use of specific microbial starter in the cassava chip fermentation for fercaf production will direct the fermentation process, maintaining a high quality of the produced flour. Thereby, the availability of an easy-to-use microbial starter is important for the production of fermented cassava flour. The aim of this study was to evaluate vacuum drying methods in the preparation of microbial starter for fermented cassava flour production. In particular, the effects of carrier media, drying and storage temperature on cell viability in dry starter were tested. The results showed that different methods should be applied to different microbial species. Bacillus subtilis and Aspergillus Oryza should be prepared using fercaf as the carrier media at a drying temperature of 55 °C, whereas Lactobacillus plantarum starter should be prepared using skim milk as the carrier media at a drying temperatur of 40°C. Apart from B. subtilis, the starters should be stored in a refrigerator.
DETERMINATION OF THE SITE AMPLIFICATION ON DEEP SOIL LAYER USING 1-D SITE RESPONSE ANALYSIS (CASE STUDY: JAKARTA CITY, INDONESIA) Delfebriyadi, Delfebriyadi; Irsyam, Masyhur; Hutapea, Bigman M.; Imran, Iswandi; Asrurifak, Muhammad
Journal of Engineering and Technological Sciences Vol 51, No 6 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2019.51.6.6

Abstract

The dynamic response of deep soil layers is used in the development of microzonation maps. The empirical correlation between standard penetratation blow count numbers and S-wave velocity was derived for practical purposes in site characterization based on local data in a case study in Jakarta, Indonesia. For estimating the intensity of potential earthquake shaking at the ground surface as a function of depth to the bedrock surface layer, 1-D site response analysis was carried out in 5745 simulations. The site amplification values were then evaluated by dividing the spectral acceleration (SA) at ground surface by the SA at rock outcrop. Plots of the SA amplification values at interested depth intervals of the bedrock surface layer were assigned. The results showed that the site amplification values estimated by considering the local depth of the bedrock surface layer were generally smaller than the SA amplification values from the Indonesian seismic building code SNI-1726-2012. Also, there appears to exist a tendency of lower levels of mean regression of amplification, in particular for the soft soil site class.
SOLVENT EXTRACTION OPTIMIZATION OF CHLOROPHYLL DYE FROM CONOCARPUS LANCIFOLIUS LEAVES Jassim, Nawras Jameel
Journal of Engineering and Technological Sciences Vol 52, No 1 (2020)
Publisher : ITB Journal Publisher, LPPM ITB

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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.
IDENTIFICATION OF MICRO-PLASTICS (MPS) IN CONVENTIONAL TAP WATER SOURCED FROM THAILAND Kankanige, Dinuka; Babel, Sandhya
Journal of Engineering and Technological Sciences Vol 52, No 1 (2020)
Publisher : ITB Journal Publisher, LPPM ITB

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Abstract

In a period when MP contamination of drinking water is a great concern, this study focused on the size- and morphology-based count, and polymeric identification of plastic particles in tap water sourced from Thailand. A total of 45 human consumable samples (each 1 L) were collected at Thammasat University. The average MP counts sorted by Nile Red tagging were 56.0±14.0 p/L (6.5-53 µm) and 21.0±7.0 p/L (53-300 µm), while those found by optical microscopic observations were 13.0±5.0 p/L (300-500 µm) and 6.0±3.0 p/L (? 500 µm). A significantly high MP amount was observed in the 6.5-53 µm fraction. Fibers dominated in all samples, accounting for 58% of the particle count. Most ? 300 µm particles tested by ATR-FT-IR spectroscopy were confirmed to be polymeric, identified as PE, PVC, PET, PA, PTFE, PP, and PAM. These particles may have escaped from the treatment plant or were added along the water distribution network. Since MPs in drinking water constitute a potential health risk by exposing humans to direct plastics intake, MP contamination in water supply systems should be controlled.
RESULTS COMPARISON FOR HAT-SHAPED, DOUBLE-NOTCH AND PUNCH TESTING OF SPLIT HOPKINSON SHEAR BAR TECHNIQUE Budiwantoro, Bagus; Faizah, Iffah; Prabowo, Dini A.; Febrinawarta, Burhan; Kariem, Muhammad Agus
Journal of Engineering and Technological Sciences Vol 51, No 6 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2019.51.6.5

Abstract

The split Hopkinson shear bar (SHSB) test is a modification of the high rate-impact test using a split Hopkinson pressure bar (SHPB). The SHSB has been developed for a variety of techniques, for example, the hat-shaped (circular or flat), double-notch, and punch (with or without notch) techniques. The main purpose of this study was to compare these three techniques to determine the shear stress-shear strain of aluminum alloy 2024-T351. The study was conducted using the Abaqus/CAE® software. The circular hat-shaped and punch (with and without notch) techniques used a quarter-section solid 3D model. The flat hat-shaped and double-notch techniques used a half-section solid 3D model. This study successfully tested and compared the three SHSB techniques, with a number of considerations, i.e. the same parameter values for kinetic energy, shear area and shear angle. Each technique has its own advantages and disadvantages in terms of force equilibrium, flow stress fluctuation, constant strain rate, machine-ability, ease of experiment, etc. The optimum technique among the three is the hat-shaped technique.
COMPARISON OF SURFACE CHARACTERISTICS OF MEDICAL-GRADE 316L STAINLESS STEEL PROCESSED BY SAND-BLASTING, SLAG BALL-BLASTING AND SHOT-BLASTING TREATMENTS Arifvianto, Budi; Mahardika, Muslim; Salim, Urip Agus; Suyitno, Suyitno
Journal of Engineering and Technological Sciences Vol 52, No 1 (2020)
Publisher : ITB Journal Publisher, LPPM ITB

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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.
COMPARATIVE STUDY OF BUILDING ENVELOPE COOLING LOADS IN AL-AMARAH CITY, IRAQ Al-Yasiri, Qudama; Al-Furaiji, Mushtaq A.; Alshara, Ahmed K.
Journal of Engineering and Technological Sciences Vol 51, No 5 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2019.51.5.3

Abstract

In recent years, the summer season in Iraq has become longer and hotter than before, leading to high cooling loads inside buildings and increased demand for electrical energy. The use of sustainable energy and insulation techniques for building envelopes are reasonable solutions for overcoming harsh weather conditions and reaching acceptable thermal comfort levels. In this study, a survey on more than 60 residential buildings in Al-Amarah City, Iraq, was conducted on 21 July 2018 to examine the nature of the most common construction materials used in the building envelopes. Furthermore, the cooling loads of building envelope elements, e.g. roof, external walls and windows, was calculated using the cooling load temperature difference/solar cooling load/cooling load factor method of ASHRAE. The results were tabulated and compared for each combination of elements. The results showed that reflective glass is the optimal choice for exterior windows. The ?clay?insulation?fired clay bricks?cement mortar? and ?cement mortar?thermo-stone bricks?cement mortar?gypsum mortar? combination layers performed well for roof and external wall installations, respectively. Several recommendations were deduced from this study, which can be used as guidelines for construction authorities in Al-Amarah City and individuals interested in energy-efficient buildings.
DEVELOPMENT OF ELECTRODE DEPOSITION METHODS FOR SCALE-UP OF DYE SENSITIZED SOLAR CELLS Mutiari, Anies; Ananda, Wisnu; Widiatmoko, Pramujo; Devianto, Hary; Nurdin, Isdiriayani; Adriaan, Adriaan; Utomo, Mhd Ridho; Koto, Hilham Zamriko
Journal of Engineering and Technological Sciences Vol 52, No 1 (2020)
Publisher : ITB Journal Publisher, LPPM ITB

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Abstract

This research studied the effect of electrode deposition method on the performance of dye-sensitized solar cells (DSSCs). Four deposition methods (bar coating, doctor blade coating, screen printing, and spray coating) were compared. For commercial production purposes, applicability of the methods to a scaled-up DSSC was studied. In order to minimize the production cost, commercial activated carbon was utilized as counter electrode. The experimental results showed that the doctor blade technique provided the best DSSC performance among the investigated methods. Based on the study of cell I-V characteristics, the photoelectric conversion efficiency of the DSSC with an electrode active area of 70 cm2 was significantly lower than with 5 cm2 despite using the same deposition method. The electrochemical characteristics of the cells were further studied using electrochemical impedance analysis.
STRUCTURAL TOPOLOGY OPTIMIZATION OF BRAKE DISC USING THE EQUIVALENT MOVING LOAD METHOD Zhang, Shengfang; Yin, Jian; Liu, Yu; Ma, Fujian; Sha, Zhihua; Yang, Dapeng
Journal of Engineering and Technological Sciences Vol 51, No 6 (2019)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2019.51.6.4

Abstract

During the braking process, the brake disc is subjected to the moving load. The process-point of the moving load moves along a certain trajectory, which makes it difficult to design the brake disc structure by using a traditional topology optimization method. The novel Equivalent Moving Load (EML) method proposed in this paper aims to solve this problem. According to the principle of continuous photographing technology, a mathematical model was established by using the round inward polygonal approximation algorithm. The EML method equalizes the continuous dynamic load action to many finite working conditions by geometric approximation. These working conditions are placed along the trajectory. The structure of the brake disc is then optimized by the EML method. Additionally, the influence of the layout style of the brake pads and the total number of working conditions on the optimization result are discussed in this paper. The optimization results showed that the new structure is a three-annulus structure. The weight of the new structure is reduced by 57.95% compared to the initial structure by structural topology optimization using the EML method. It was proved that structural topology optimization using the EML method is efficient in optimizing a structure subjected to dynamic load.
COVER JETS VOL. 50 NO. 5, 2018 Technological Sciences, Journal of Engineering and
Journal of Engineering and Technological Sciences Vol 50, No 5 (2018)
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