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INDONESIA
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
 66   67   68   69   70 
Characteristics of Oxidative Storage Stability of Canola Fatty Acid Methyl Ester Stabilised with Antioxidants Tirto Prakoso; Parncheewa Udomsap; Akiko Tanaka; Toshihiro Hirotsu; Shinichi Goto
Journal of Engineering and Technological Sciences Vol. 44 No. 3 (2012)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2012.44.3.7

Abstract

The  storage  effects  on  the  oxidation  characteristics  of  fatty  acid methyl ester of canola oil (CME) were investigated  in this study.CME stabilised with  two  antioxidants, i.e.2,6-di-tert-bytyl-p-cresol  (BHT) and 6,6-di-tert-butyl-2, 2'-methylendi-p-cresol  (BPH),  was  stored at 20, 40 and  60°C.The  oxidation stability data  were measured  by  the  Rancimat test  method and  it was  found  that both BHT and BPH  addition increased  the oxidation resistance of  the  CME.  The results showed that when BPH or BHT was added at a concentration of 100 ppm, the oxidation induction period of the neat CME samples increased from 5.53 h to 6.93  hand  6.14 h,  respectively.  Comparing both antioxidants,  BPH  proved to be more  effective  in  increasing  the  oxidation  resistance  when  both  antioxidants were added at the same concentration.  Furthermore, the oxidation induction timedecreased  linearly  with  the  storage  time.  It  was  shown  that  the  oxidation occurred  rapidly  in  the  first  8  weeks  of  storage.  Later,  a  kinetic  study  was undertaken  and  first-order  kinetics  were  applied  to  explain  the  oxidation characteristics of  the  CME added with antioxidants. This kinetic study focused on  exploiting  the  activation  energy  values  obtained  from  the  Arrheniusequations. Also, the  oxidation effects on  other  quality parameters, including acid value, peroxide value, kinematic viscosity, and water content, were examined.
Complex Morphology of Subducted Lithosphere in the Mantle below the Molucca Collision Zone from Non-linear Seismic Tomography Sri Widiyantoro
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.1

Abstract

Results of seismic studies presented in previous publications depict two opposing subducted oceanic lithospheric slabs under the Molucca region. This unique structure is related to the arc-arc collision between the Halmahera and Sangihe arcs. Recently, we have revisited the complex subduction zone structure by employing a non-linear tomographic imaging technique in which 3-D ray tracing has been implemented. We have used P- as well as S-wave arrival times from carefully reprocessed global data set. The results provide some improvements in the positioning of wave-speed anomalies. Consistent with earlier results, the new P-wave model depicts the two opposing subducted slabs of the Molucca Sea plate. The intriguing new observation is that the westward dipping slab appears to penetrate into the lower mantle by taking the form of folded slab. We envisage that the folding behavior may have been caused by the shift of the whole subduction system in the Molucca region toward the Eurasian continent due to the westward thrust of the Pacific plate combined with the large left-lateral movement of the Sorong fault. The inversion of traveltime residuals of direct S phases strongly confirms the new observation.
Study on Rayleigh Wave Inversion for Estimating Shear-wave Velocity Profile T. A. Sanny; Yoes Avianto
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.2

Abstract

Rayleigh wave or ground roll is a noise in seismic body waves. However, how to use this noise for soil characterization is very interesting since Rayleigh wave phase velocity is a function of compression-wave velocity, shear-wave velocity, density and layer thickness. In layered-medium Rayleigh wave velocity also depends on wavelength or frequency, and this phenomenon is called dispersion. Inversion procedure to get shear-wave velocity profile needs a priori information about the solution of the problem to limit the unknown parameters. The Lagrange multiplier method was used to solve the constrained optimization problems or well known as a smoothing parameter in inversion problems. The advantage of our inversion procedure is that it can guarantee the convergence of solution even though the field data is incomplete, insufficient, and inconsistent. The addition of smoothing parameter can reduce the time to converge. Beside numerical stability, the statistical stability is also involved in inversion procedure. In field experiment we extracted ground roll data from seismic refraction record. The dispersion curves had been constructed by applying f-k analysis and f-k dip filtering. The dispersion curves show the dependence of Rayleigh wave phase velocities in layered media to frequency. The synthetic models also demonstrate the stability and the speed of inversion procedure.
Surface Vibration Reconstruction using Inverse Numerical Acoustics F. Martinus; D. W. Herrin; A. F. Seybert
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.5

Abstract

This paper explores the use of inverse numerical acoustics to reconstruct the surface vibration of a noise source. Inverse numerical acoustics is mainly used for source identification. This approach uses the measured sound pressure at a set of field points and the Helmholtz integral equation to reconstruct the normal surface velocity. The number of sound pressure measurements is considerably less than the number of surface vibration nodes. An overview of inverse numerical acoustics is presented and compared with other holography techniques such as nearfield acoustical holography and the Helmholtz equation least squares method. In order to obtain an acceptable reproduction of the surface vibration, several critical factors such as the field point selection and the effect of experimental errors have to be handled properly. Other practical considerations such as the use of few measured velocities and regularization techniques will also be presented. Examples will include a diesel engine, a transmission housing and an engine cover.
Cost Minimization Model of Gas Transmission Line for Indonesian SIJ Pipeline Network Septoratno Siregar; Edy Soewono; Daniel Siregar; Satya A. Putra; Yana Budicakrayana
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.3

Abstract

Optimization of Indonesian SIJ gas pipeline network is being discussed here. Optimum pipe diameters together with the corresponding pressure distribution are obtained from minimization of total cost function consisting of investment and operating costs and subjects to some physical (Panhandle A and Panhandle B equations) constraints. Iteration technique based on Generalized Steepest-Descent and fourth order Runge-Kutta method are used here. The resulting diameters from this continuous optimization are then rounded to the closest available discrete sizes. We have also calculated toll fee along each segment and safety factor of the network by determining the pipe wall thickness, using ANSI B31.8 standard. Sensitivity analysis of toll fee for variation of flow rates is shown here. The result will gives the diameter and compressor size and compressor location that feasible to use for the SIJ pipeline project. The Result also indicates that the east route cost relatively less expensive than the west cost.
Luminescent Polymer Electrolyte Composites Using Silica Coated-Y2O3:Eu as Fillers Mikrajuddin Abdullah; Kikuo Okuyama
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.6

Abstract

Luminescent polymer electrolyte composites composed of silica coated Y2O3:Eu in polyethylene glycol (PEG) matrix has been produced by initially synthesizing silica coated Y2O3:Eu and mixing with polyethylene glycol in a lithium salt solution. High luminescence intensity at round 600 nm contributed by electron transitions in Eu3+ (5D0 → 7F0, 5D0 → 7F1, and 5D0 → 7F3 transitions) were observed. The measured electrical conductivity was comparable to that reported for polymer electrolyte composites prepared using passive fillers (non luminescent). This approach is therefore promising for production of high intensity luminescent polymer electrolyte composites for use in development of hybrid battery/display.
Ground Deformation during Papandayan Volcano 2002 Eruption as Detected by GPS Surveys Hasanuddin Z. Abidin; H. Andreas; M. Gamal; Ony K. Sugandar; Irwan Meilano; M. Hendrasto; M. A. Kusuma; D. Darmawan; M. A. Purbawinata; A. D. Wirakusumah; F. Kimata
Journal of Engineering and Technological Sciences Vol. 35 No. 1 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.1.4

Abstract

Papandayan is an A-type active volcano located in the southern part of Garut Regency, about 70 km southeast of Bandung, Indonesia. Its earliest recorded eruption, and most violent and devastating outburst occurred in 1772 and the latest eruptions occurred in the period of 11 November to 8 December 2002, and consisted of freatic, freatomagmatic and magmatic types of eruption.During the latest eruption period, GPS surveys were conducted at several points inside and around the crater in a radial mode using the reference point located at Papandayan observatory around 10 km from the crater. At the points closest to the erupting craters, GPS displacements up to a few dm were detected, whereas at the points outside the crater, the displacements were in the cm level. The magnitude of displacements observed at each point also show a temporal variation according to the eruption characteristics. The results show that deformation during eruption tends to be local, e.g. just around the crater. Pressure source is difficult to be properly modeled from GPS results, due to limited GPS data available and differences in topography, geological structure and/or rheology related to each GPS station.
Analysis of Surface Wave Attenuation in Mangrove Forests Safwan Hadi; Hamzah Latief; Muliddin Muliddin
Journal of Engineering and Technological Sciences Vol. 35 No. 2 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.2.1

Abstract

This paper presents an analytical study on surface wave attenuation in mangrove forest using analytical model developed by Massel et.al. (1999). The energy dissipation in the frequency domain is determined by treating the mangrove forest as a random media with certain characteristics using the geometry of mangrove trunks and their locations. Initial nonlinear governing equations are linearized using the concept of minimalization in the stochastic sense and interactions between mangrove trunks and roots have been introduced through the modification of the drag coefficients. To see the effectiveness of the mangrove forest in attenuating wave energy the analytical model was applied to two types of mangrove forest i.e. Rhizophora and Ceriops forests. The resulting rate of wave energy attenuation depends strongly on the density of the mangrove forest, and on diameter of mangrove roots and trunks. More effective wave energy attenuation is shown by Rhizophora.
Gas Deliverability Model with Different Vertical Wells Properties L. Mucharam; P. Sukarno; S. Siregar; Z. Syihab; E. Soewono; M. Apri; F. Irzal
Journal of Engineering and Technological Sciences Vol. 35 No. 2 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.2.3

Abstract

We present here a gas deliverability computational model for single reservoir with multi wells. The questions of how long the gas delivery can be sustained and how to estimate the plateau time are discussed here. In order to answer such a question, in this case, a coupling method which consists of material balance method and gas flow equation method is developed by assuming no water influx in the reservoir. Given the rate and the minimum pressure of gas at the processing plant, the gas pressure at the wellhead and at the bottom hole can be obtained. From here, the estimation of the gas deliverability can be done. In this paper we obtain a computational method which gives direct computation for pressure drop from the processing plant to the wells, taking into account different well behavior. Here AOF technique is used for obtaining gas rate in each well. Further Tian & Adewumi correlation is applied for pressure drop model along vertical and horizontal pipes and Runge-Kutta method is chosen to compute the well head and bottom hole pressures in each well which then being used to estimate the plateau times. We obtain here direct computational scheme of gas deliverability from reservoir to processing plant for single reservoir with multi-wells properties. Computational results give different profiles (i.e. gas rate, plateau and production time, etc) for each well. Further by selecting proper flow rate reduction, the flow distribution after plateau time to sustain the delivery is computed for each well.
Characteristics of Response of Piezoelectric Actuators in Electron Flux Excitation Philip C. Hadinata; John A. Main
Journal of Engineering and Technological Sciences Vol. 35 No. 2 (2003)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.eng.sci.2003.35.2.2

Abstract

In this paper the working parameters of non-contact strain control for piezoelectric ceramics are evaluated. The piezoelectric material functions as an actuator that transforms electrical into mechanical energy, and the electrical input is carried out by electron flux on the positive surface. The sample is exposed to some quasi-static inputs, and its responses are recorded using strain gages. The data shows faster and more stable response in the positive regime, but significantly slower response with drift in the negative regime. An electron collector is introduced on the positive surface to enhance the response in the negative regime. Theoretical analyses of energy transfer and electron movements is discussed, and a string of working conditions for controlling the surface strain of piezoelectric material are given as conclusions.

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