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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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Synthesis of NaY Zeolite Using Mixed Calcined Kaolins Subagjo, Subagjo; Rahayu, Endang Sri; Samadhi, Tjokorde Walmiki; Gunawan, Melia Laniwati
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Kaolin is one of several types of clay minerals. The most common crystalline phase constituting kaolin minerals is kaolinite, with the chemical composition Al2Si2O5(OH)4. Kaolin is mostly used for manufacturing traditional ceramics and also to synthesize zeolites or molecular sieves. The Si-O and Al-O structures in kaolin are inactive and inert, so activation by calcination is required. This work studies the conversion of kaolin originating from Bangka island in Indonesia into calcined kaolin phase as precursor in NaY zeolite synthesis. In the calcination process, the kaolinite undergoes phase transformations from metakaolin to mullite. The Bangka kaolin is 74.3% crystalline, predominantly composed of kaolinite, and 25.7% amorphous, with an SiO2/Al2O3 mass ratio of 1.64. Thermal characterization using simultaneous DSC/TGA identified an endothermic peak at 527Â°C and an exothermic peak at 1013Â°C. Thus, three calcination temperatures (700, 1013, and 1050 Â°C) were selected to produce calcined kaolins with different phase distributions. The best product, with 87.8% NaY zeolite in the 54.7% crystalline product and an SiO2/Al2O3 molar ratio of 5.35, was obtained through hydrothermal synthesis using mixed calcined kaolins with a composition of K700C : K1013C : K1050C = 10 : 85 : 5 in %-mass, with seed addition, at a temperature of 93Â Â°Cand a reaction time of 15 hours.

Thermal Energy Storage Optimization in Shopping Center Buildings Biyanto, Totok R.; Alhikami, Akhmad F.; Nugroho, Gunawan; Hantoro, Ridho; Bayuaji, Ridho; Firmanto, Hudiyo; Waluyo, Joko; Sonhaji, Agus Imam
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

In this research, cooling system optimization using thermal energy storage (TES) in shopping center buildings was investigated. Cooling systems in commercial buildings account for up to 50% of their total energy consumption. This incurs high electricity costs related to the tariffs determined by the Indonesian government with the price during peak hours up to twice higher than during off-peak hours. Considering the problem, shifting the use of electrical load away from peak hours is desirable. This may be achieved by using a cooling system with TES. In a TES system, a chiller produces cold water to provide the required cooling load and saves it to a storage tank. Heat loss in the storage tank has to be considered because greater heat loss requires additional chiller capacity and investment costs. Optimization of the cooling system was done by minimizing the combination of chiller capacity, cooling load and heat loss using simplex linear programming. The results showed that up to 20% electricity cost savings can be achieved for a standalone shopping center building.

Enhancement of Chlorella vulgaris Biomass Cultivated in POME Medium as Biofuel Feedstock under Mixotrophic Conditions Nur, M.M. Azimatun; Hadiyanto, H.
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Microalgae cultivated in mixotrophic conditions have received significant attention as a suitable source of biofuel feedstock, based on their high biomass and lipid productivity. POME is one of the wastewaters generated from palm oil mills, containing important nutrients that could be suitable for mixotrophic microalgae growth. The aim of this research was to identify the growth of Chlorella vulgaris cultured in POME medium under mixotrophic conditions in relation to a variety of organic carbon sources added to the POME mixture. The research was conducted with 3 different carbon sources (D-glucose, crude glycerol and NaHCO3) in 40% POME, monitored over 6 days, under an illumination of 3000 lux, and with pHÂ =Â 7. The biomass was harvested using an autoflocculation method and dry biomass was extracted using an ultrasound method in order to obtain the lipid content. The results show that C. vulgaris using D-glucose as carbon source gained a lipid productivity of 195 mg/l/d.

Porosity and Permeability Development of the Deep-Water Late-Oligocene Carbonate Debris Reservoir in the Surroundings of the Paternoster Platform, South Makassar Basin, Indonesia Pireno, Gadjah E.; Suparka, Emmy; Noeradi, Dardji; Ascaria, Alit
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

The discovery of gas within the carbonate debris reservoir of the late Oligocene Berai formation near the Paternoster Platform, South Makassar Basin, is a new exploration play in Indonesia. The carbonate was deposited in a deep-water environment and is a good example of a less well known carbonate play type. The carbonate debris reservoir in this area consists of re-deposited carbonate, originally located on a large carbonate platform that has been eroded, abraded and transported to the deep-water sub-basin. The limestone clasts range from pebble-size to boulders within a matrix of micrite and fine abraded bioclasts. This carbonate debris can be divided into clast-supported facies and matrix-supported facies. The matrix-supported facies have much better porosity and permeability than the clast-supported facies. Porosity in both the transported clasts and the matrix is generally mouldic and vuggy, resulting mostly from dissolution of foraminifera and other bioclastics after transportation. In the matrix intercrystal porosity has developed. The porosity and permeability development of this deep-water carbonate debris was controlled by a deep-burial diagenetic process contributed by the bathyal shales de-watering from the Lower Berai shales beneath the carbonate reservoir and the Lower Warukin shales above the carbonate reservoir during the burial process.

Performance Calculation of Floating Wind Turbine Tension Leg Platform in the South China Sea Wang, Hai Feng; Fan, You Hua
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

The harvesting of wind energy is expected to increase greatly in thefuture because of its stability, abundance, and renewability in large coastal states such as China. The floating support structure will likely become the major structural form for wind turbines in the future due to its cost advantages when the water depth reaches 50 m. The 5MW wind turbine model from National Renewable Energy Lab (NREL) and the modified tension leg platform model proposed by Harbin Institute of Technology (HIT) were applied to certain sea conditions in the South China Sea in order to consider the effects of external load coupling actions. In this study, the internal force, mooring system force, as well as the acceleration, displacement and velocity of the floating structure of the modified HIT Tension Leg Platform (HIT-TLP) were calculated. During this process, the physical parameters of its tension leg structure at a specific frequency domain were obtained to find the technical reserves for its practical application in the future.

Alkaline Treatment of Oil Palm Frond Fibers by Using Extract of Oil Palm EFB Ash for Better Adhesion toward Polymeric Matrix Fatra, Warman; Sanjaya, Randi; Zulfansyah, Zulfansyah; Rionaldo, Hari; Helwani, Zuchra
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

In Indonesia, 187 million tons of biomass were produced from 8.11 million ha of oil palm plantation in 2009. This massive amount of biomass mainly consists of oil palm fronds (OPF) and oil palm empty fruit bunches (EFB), which are normally categorized as waste. The properties of OPF fibers compared to those of synthetic fibers, such as low density, low cost, less abrasion of equipment, and safer production, makes them an attractive reinforcement for composite materials. In this work, the utilization of oil palm empty fruit bunch ash for OPF fiber-polyester resin composite and the effect of process conditions were studied. Water absorption, tensile and flexural strength were used to characterize the effects of alkaline treatment on modified OPF fibers in polyester resin. The investigation focused on the effect of alkaline treatment time. Treatment temperature and liquid to solid ratio were analyzed using Response Surface Method-Central Composite Design (RSM-CCD). The highest tensile strength (44.87 MPa) was achieved at 12 hours soaking time, at 40Â°C treatment temperature and 5:1 water to ash ratio. The highest flexural strength (120.50 MPa) was obtained at 1.3 hours soaking time, 4 dissolving ratio and 35Â°C treatment temperature. The lowest water absorption of composite (3.00%) was achieved at the longest soaking time (14.7 hours), 4 dissolving ratio and 35Â°C treatment temperature. Variance of soaking time, dissolving ratio and temperature in the alkaline treatment process using extract of oil palm empty fruit bunch ash significantly affected the mechanical and physical properties of the oil palm frond fibers reinforced composite.

Non-Imaging Acoustical Properties in Monitoring Arteriovenous Hemodialysis Access. A Review Mohd Noor, Anas
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

The limitations of the gold standard angiography technique in arteriovenous access surveillance have opened a gap for researchers to find the best way to monitor this condition with low-cost, non-invasive and continuous bedside monitoring. The phonoangiography technique has been developed prior to these limits. This measurement and monitoring technique, associated with intelligence signal processing, promises better analysis for early detection of hemodialysis access problems, such as stenosis and thrombosis. Some research groups have shown that the phonoangiography technique could identify as many as 20% of vascular diameter changes and also its frequency characteristics due to hemodialysis access problems. The frequency characteristics of these acoustical signals are presented and discussed in detail to understand the association with the stenosis level, blood flows, sensor locations, fundamental frequency bands of normal and abnormal conditions, and also the spectral energy produced. This promising technique could be used in the near future as a tool for pre-diagnosis of arteriovenous access before any further access correction by surgical techniques is required. This paper provides an extensive review of various arteriovenous access monitoring techniques based on non-imaging acoustical properties.

Analysis of the Strength of Timber and Glulam Timber Beams with Steel Reinforcement Usman, Arie Putra; Sugiri, Saptahari
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Indonesia is a tropical country with abundant tropical timber that can be used as a building material. Wood is a renewable material, thus making it an environmentally friendly construction material. However, the dimensional limitations of solid wood may pose problems in structural constructions. Wood material also has some disadvantages, such as brittle failure. However, the ductility of wood can be increased because of plasticity occurring in the compression zone. Wood material with good ductility can be obtained by reinforcing it in the tensile zone. This study is about the strength of wood material for use as a material for structural elements. Based on the analytical findings, the bending capacity of wood can be improved by adding reinforcements to the tensile zone.

Partial Hydrogenation of Calophyllum Inophyllum Methyl Esters to Increase the Oxidation Stability Joelianingsih, Joelianingsih; Putra, P.; Hidayat, A.W.; Fajar, R.
Journal of Engineering and Technological Sciences Vol 47, No 5 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Calophyllum inophyllum methyl esters have a low oxidation stability value (5-6 h) caused by high amounts of polyunsaturated fatty acid methyl esters (FAME), especially methyl linoleate. Partial hydrogenation was done to reduce the number of polyunsaturated FAME to transform them into mono-unsaturated. This was performed at 6 bar and 900 rpm with Pd/Al2O3 solid catalyst in a reactor with a capacity of 1 liter. The research purpose was to learn the effects of reaction temperature (80; 100; 120Â°C) and time (1; 1.5; 2 h) on the FAME composition. The optimum condition of the experiment was obtained at 120Â°C for 1 h, with 15.47 h as the oxidation stability value, 17.8Â°C as the cloud point value, and 51.17 as the cetane number. Under this condition, the methyl linoleate content decreased by 59.89% w/w (from 21.869% to 8,770% w/w) and methyllinoleate hydrogenated into methyl elaidate. Meanwhile, the methyl linolenate content decreased by 85,37% w/w (from 0.205% to 0.030% w/w) and methyl linolenate hydrogenated into methyl linolelaidate. These results show that the research met the following standards: a minimum oxidation stability value of 10 h in accordance with the World Wide Fuel Charter (WWFC) 2009, a maximum cloud point value of 18Â°C and a minimum cetane number 51 in accordance with SNI 7182-2012. The physical properties values of the Calophyllum inophyllum methyl esters were predicted using the empirical equations.

Optimum Fermentation Process for Red Macroalgae Gelidium latifolium and Gracillaria verrucosa Kawaroe, Mujizat; Sari, Dahlia Wulan; Hwangbo, Junkwon; Santoso, Joko
Journal of Engineering and Technological Sciences Vol 47, No 6 (2015)
Publisher : ITB Journal Publisher, LPPM ITB

Red macroalgae have the potential to be processed into bioethanol due to their high carbohydrate and low lignin content. Gelidium latifolium and Gracilaria verrucosa are red macroalgae commonly found in Indonesian seas. Sometimes an over-supply of red macroalgae is rejected by the food industry, which opens up opportunities for others uses, e.g. for producing bioethanol. The objectives of this research were to analyze the influence of sulfuric acid concentration on hydrolysis of G. latifolium and G. verrucosa and to calculate the optimum fermentation process to produce bioethanol. G. latifolium and G. verrucosa were hydrolyzed using H2SO4 at concentrations of 1%, 2%, 3%, and 4%, at a temperature of 121Â Â°C and a pressure of 1.5 bar for 45 minutes. The process of fermentation was done using Saccharomyces cerevisiae in anaerobic conditions for 4, 5, 6 and 7 days. The results show that the optimum H2SO4 concentrations to hydrolyze G. latifolium and G. verrucosa were 1% and 2% respectively. The number of S. cerevisiae cells in hydrolysate G. latifolium and G. verrucosa increased in the third adaptation. S. cerevisiae can convert sugar from G. latifolium and G. verrucosa into bioethanol through fermentation. The highest bioethanol yields were achieved on days five and six. Therefore, red macroalgae can be seen as a potential raw material for bioethanol production.

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