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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 8 Documents
Search results for , issue "Vol. 45 No. 2 (2013)" : 8 Documents clear
Behavior of Natural Estrogens in Activated Sludge: Biodegradation in Semicontinuous Reactor under Aerobic, Anaerobic and Sequential Anaerobic/Aerobic Conditions Reni Desmiarti; Fusheng Li
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.1

Abstract

The behavior of natural estrogens was examined by separately spiking 17β-estradiol (E2) and estrone (E1) into semicontinuous activated sludge reactors operated under aerobic, anaerobic and sequential anaerobic/aerobic conditions. Under aerobic and anaerobic conditions, E1 was formed from E2. The cactivated sludge; biodegradation; estrogens; estradiol; estroneonversion of E1 to E2 was did not occur under aerobic conditions. The maximum conversion of E2 to E1 was higher than the maximum conversion of E1 to E2. Overall, the degradation rate of E2 (kE2) was much faster than that of E1 (kE1). The findings suggest that E1 is probably more persistent than E2 in effluent of sewage treatment plants.
Velocity versus Offset (VVO) Estimation Using Local Event Correlation and Its Application in Seismic Processing & Analysis S. Supriyono; Awali Priyono; Wahyu Triyoso; Hilman Mardiyan
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.2

Abstract

Conventional velocity analysis is usually done in a relatively spare grid, for instance every half kilometers, during the processing of seismic data. It is very laborious work and very subjective. To deliver an accurate velocity picking, processing geophysicists must have a good understanding of geological background of area being analyzed and experiences. Velocity errors often occur during picking. Proper quality control and checking are a must. A good and reliable velocity field is very important in seismic processing for achieving high-quality seismic images as well as for delivering an accurate depth conversion. The new method presented here, was developed to correct velocity errors automatically by means of residual velocity correction, and to produce an offset-dependent RMS velocity field at the same time. The method is data driven, based on the normal move out equation (NMO) and measuring the local even correlation between adjacent traces. The stacking velocity is derived simply by averaging the velocity field. The proposed method was tested on synthetic and real data examples with good result. The velocity field has certain characteristics related to hydrocarbon presence. Supriyono (2011 and 2012) developed a new DHI method using velocity gradient attributes by cross-plotting the velocity versus offset (VVO). The velocity gradient exhibits high anomalous values in the presence of gas.
Modification of Attenuation Rate in Range Normalization of Echo Levels for Obtaining Frequency-dependent Intensity Data from 0.6MHz and 1.0MHz Devices R. Poerbandono; Totok Suprijo
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.3

Abstract

This investigation aims to propose an attenuation rate for range normalization of echo amplitudes recorded by an acoustic backscattering instrument working at a frequency of 1.0 MHz. The intention of the use of such an attenuation rate is to obtain equal echo levels when using a device from the same family of products with a different working frequency, i.e. a 0.6 MHz instrument, at an identical site. This work is based on a field experiment with a 1.0 MHz Acoustic Wave and Current (AWAC) profiler and a 0.6 MHz Aquadopp profiler. Both profilers were deployed upward, side-by-side in the Semak Daun reef lagoon, Seribu Islands, Java Sea, Indonesia. It was found that the proposed attenuation rate for the 1.0 MHz instrument was one-order magnitude higher with respect to the one used for the 0.6 MHz instrument, and logarithmically depth dependent. The proposed attenuation rate for the 1.0 MHz AWAC is "“7.925log(R) + 8.551, with R is the slant range from the transducers to the measured layer. Accordingly, the overall agreement between the 1.0 MHz AWAC echo amplitude and the one recorded by the 0.6 MHz Aquadopp was improved by 18dB, which is quite significant considering that the average echo amplitude discrepancy recorded by each transducer was 2.4dB.
CH4 Emission Model from Bos Primigenius Waste in Fish-Water: Implications for Integrated Livestock-Fish Farming Systems Joshua O. Okeniyi; Adedamola O. Ogunsanwo; Nosadeba W. Odiase; Uchechukwu E. Obiajulu; Elizabeth T. Okeniyi
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.4

Abstract

This paper studies a methane (CH4) emission model from the waste of cattle (B. primigenius) based on trends in integrated livestock-fish farming adoption by farmers in Nigeria. Dung of B. primigenius was employed as substrate in fish-water, obtained from a fish-rearing farm, as a matrix medium for simulating a low-oxygen wastewater environment of an agriculture-aquaculture system. A substrate to fish-water mass ratio of 1:3 was used, developed in a laboratory-size digesting reactor system. Volumetric readings, at ambient temperature conditions and with a retention time of thirty-two days, were then subjected to the logistic probability density function, and tested against correlation coefficient and Nash-Sutcliffe coefficient of efficiency criteria. The readings show that a volume of CH4-containing gas as high as 65.3 x 10−3 dm3 was produced on the 13th day from the B. primigenius substrate. Also, production of 234.59 x 10−3 dm3/kg CH4-containing gas, totaling 703.76 x 10−3 dm3, was observed through the studied retention time. The 60% CH4 constituent model of the measured gas generation showed a potency of 2.0664 kg emission per animal, which is equivalent to 43.3944 CO2eq of global warming potential (GWP) annually per animal. This bears environmental and climate change implications, and therefore alternative sustainable practices for integrated livestock-fish farming adoption are suggested.
The Influence of Cross-Sectional Shape and Orientation of Micropillar Surface on Microdroplet Formation by a Dewetting Process Bambang Arip Dwiyantoro; Shiu-Wu Chau
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.5

Abstract

In this study the dewetting process on micropillars of three different cross-sectional shapes, i.e. circular, square and triangular, was numerically investigated. The influence of the orientation of the triangular and square micropillars on the dewetting behavior was also studied. The numerical simulations showed that the cross-sectional shapes of the micropillars and their orientation play an important role in determining the flow pattern of the dewetting process, especially the evolution and movement of the meniscus across the micropillar before a microdroplet is formed. The diameter of the microdroplets is mainly determined by the capillary effect, viscous drag and fluid inertia contributed by the peeling rate and the thickness of the water layer above the micropillar. The numerical results also indicate that the hydraulic diameter of the micropillars (Dp) is one of the parameters governing the size of the microdroplets formed on the top surface of the micropillars after the dewetting process, while the microdroplet diameter is almost insensitive to the cross-sectional shape and orientation of the micropillars. The dimensionless diameter of the microdroplets (d) can then be expressed as a function of a dimensionless group, i.e. the Ohnesorge number (Oh), the capillary number (Ca), the dimensionless liquid thickness (H), and the contact angle (q).
Numerical Study of an Ejector as an Expansion Device in Split-type Air Conditioners for Energy Savings Kasni Sumeru; Shodiya Sulaimon; Farid Nasir Ani; Henry Nasution
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.6

Abstract

The present study describes a numerical approach for determining both the motive nozzle and constant-area diameters of an ejector as an expansion device, based on the cooling capacity of a split-type air-conditioner using R290 as refrigerant. Previous studies have shown that replacement of HCFC R22 with HC290 (propane) in the air conditioner can improve the coefficient of performance (COP). The purpose of replacing the capillary tube with an ejector as an expansion device in a split-type air conditioner using HC290 is to further improve the COP. In developing the model, conservation laws of mass, momentum and energy equations were applied to each part of the ejector. The numerical results show that the motive nozzle diameter remains constant (1.03 mm) under varying condenser temperatures, whereas the diameter of the constant-area decreases as the condenser temperature increases. It was also found that improvement of the COP can reach 32.90% at a condenser temperature of 55 °C. From the results mentioned above, it can be concluded that the use of an ejector can further improve the COP of a split-type air conditioner using HC290 as working fluid.
Determination of Kinetic Parameters for Methane Oxidation over Pt/γ-Al2O3 in a Fixed-Bed Reactor Vita Wonoputri; Mohammad Effendy; Yogi Wibisono Budhi; Yazid Bindar; S. Subagjo
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
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.2013.45.2.7

Abstract

This paper describes akinetic study for the determination of the kinetic parameters of lean methane emission oxidation over Pt/γ-Al2O3 in a dedicated laboratory scale fixed bed reactor. A model ofthemechanistic reaction kinetic parameters has been developed. The reaction rate model was determined using therate-limiting step method, which was integrated and optimized to find the most suitable model and parameters. Based on this study, the Langmuir-Hinshelwood reaction rate model with the best correlationis the one where the rate-limiting step is thesurface reaction between methane and one adsorbed oxygen atom. The pre-exponential factor and activation energy were 9.19 x 105 and 92.04 kJ/mol, while the methane and oxygen adsorption entropy and enthalpy were "“17.46 J/mol.K, "“2739.36 J/mol,"“16.34 J/mol.K, and "“6157.09 J/mol, respectively.
Cover Vol. 45 No.2, 2013 Journal of Engineering and Technological Sciences
Journal of Engineering and Technological Sciences Vol. 45 No. 2 (2013)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

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