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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
 63   64   65   66   67 
2-D Physical Modeling to Measure the Effectiveness of Perforated Skirt Breakwater for Short-Period Waves Harman Ajiwibowo
Journal of Engineering and Technological Sciences Vol. 43 No. 1 (2011)
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.2011.43.1.5

Abstract

The effectiveness of a breakwater can be measured by quantifying the transmission coefficient (KT). The smaller the coefficient, the better the performance of the breakwater. A physical modeling on the proposed breakwater was conducted to identify the coefficient of Perforated Skirt Breakwater (PSB). The PSB model was tested in 2-D wave flume at Ocean Wave Research Laboratory FTSL ITB, to obtain the effectiveness of PSB for short-period waves (prototype periods, Tp= 4 second and smaller). The scaling of PSB models applies the principle of Froude Similarity, where the Froude number in model equals to the Froude number in prototype (Frm=Frp). The flume is equipped with 5 resistance-type wave probes and 8-channel DAS (Data Acquisition System). Wave heights (H) and wave periods (T) data were observed both manually by visual observation and wave probes readings (processed later with method of "zero mean up-crossing" technique). The incoming wave heights (Hi) and transmitted wave heights (Ht) were measured and processed to obtain the transmission coefficient (KT). The relationships between KT and non-dimensional variables (skirt draft / incident wave height, S/Hi) are analyzed and the calculated effectiveness of the PSB for varied environmental condition is obtained to be up to 70%.
Combination of Minimum-Maximum (m-m) Attribute and Zero-INTENS-Difference (z-i-d) Attribute for Estimating Seismically Thin-Bed Thickness Eko Widi Purnomo; Zuhar Zahir Tuan Harith
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.1

Abstract

This  paper  demonstrates  a  new  alternative  way  in  estimating seismically thin-bed (below-tuning) thickness. Initial thickness is built by bandpass filtering the amplitude display of a zero-phase seismic. The filter removes the  non  minimum  and  or  non  maximum  and  left  the  maximum  and  or  the minimum of seismic amplitude. The unresolved below-tuning thickness is then corrected  by  zero-INTENS-difference  (z-i-d)  attribute.  INTENS  is  integrated energy  spectra,  an  attribute  which  can  be  derived  from  spectral  analysis.  z-i-d attribute is zero difference of INTENS between the seismic and its synthetic. The method  generates  INTENS  difference  profile  by  subtracting  seismic  INTENS and its synthetic INTENS iteratively. The iteration is controlled by dipole space shifting from  distance to closer or  vice  versa.  The true thickness is derived  by locating z-i-d which laid in INTENS different profile. It has found that, for free noise  true  seismic  and  perfect-wavelet  (a  wavelet  which  only  approximately similar  with  wavelet  which  constructing  the  true  seismic)  synthetic  seismic,  in INTENS  different  profile,  the  z-i-d  location  always  corresponds  to  true  dipole space or thickness. The method could resolve all thickness of a wedge-modeled seismic with three different dominant frequencies. When the synthetic seismic is constructed with imperfect wavelet, slightly different analysis is needed to locate z-i-d  attribute  and  the  result  is  not  as  perfect  as  when  perfect  wavelet constructing synthetic seismic. A quiet similar result is got when the method is implemented  for  noisy  wedge-modeled  seismic.  Bad  thickness  estimation  is resulted  for  20%  noise  seismic.  The  method  algorithm  is  extended  for  similar dipole polarity model and multilayer model to bring the method to real seismic data  nearer.  The  extension  is  done  by  estimating  thickness  of  every  layer  of  a stacked-wedge-modeled  seismic. The algorithm then generalized for estimating layers  thickness  with  several  thickness  combinations.  The  method  was  able  to delineate shallow channel of Stratton Field by providing good pseudo-acousticimpedance (pseudo AI) map.
Autonomous Coastal Land Cover Assessment Using Polarimetric Decomposition of SAR Data Bambang H. Trisasongko
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.2

Abstract

The  paper  reports  an  experiment  on  classification  using  fully polarimetric SAR data.  Many  reports have been presented mentioning test sites in  temperate  regions  utilizing  polarimetric  SAR  data  from  airborne  and/or spaceborne SAR sensors. However, few  studies are dedicated  to  tropical region which highly dynamic land uses are  observed.  Using the AirSAR Sungai Wain fully polarimetric data, capability to extract features in coastal region has been demonstrated  by  an  unsupervised  classification  technique  fed  by  the  CloudePottier decomposition theorem.
Synthesis of -Al2O3 Catalyst Support from Kaolin of Indonesian Origin Tjokorde Walmiki Samadhi; Subagjo Subagjo; Kevin R. Lismana; Khasin Fuadi
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.3

Abstract

Kaolin  has  been  identified  as  a  potential  raw  material  for  the production of  -Al2O3  for  hydrotreating  catalyst support. This work explores the technical  feasibility  of  applying  the  potassium  hydroxide  (KOH)  e xtraction synthesis route on kaolin  from the Belitung  Island  in Indonesia. The application of  a  published  synthesis  method  to  Belitung  kaolin  requires  an  approximately twofold  increase  in  kaolin  calcination  time,  an  increase  in  kaolin  calcination temperature from 950 to 1000 °C, and a tenfold increase in metakaolin extraction time, to obtain a specific surface area higher than 200 m2/g. The highest specific surface area of 233 m2/g was obtained when  the kaolin was calcined at 1000 °C for 24 hours, and the  metakaolin  was extracted by concentrated KOH  solution for 12 hours.  Phase characterization of the final product confirmed the formation of -Al2O3, but with the inclusion of low-surface area -Al2O3 phase.
An LMI Approach to H∞ Performance Analysis of Continuous-Time Systems with Two Additive TimeVarying Delays Wrastawa Ridwan; Bambang Riyanto Trilaksono
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.4

Abstract

This paper investigates the problem of H∞ performance analysis for continous–time systems with two additive time -varying delays in the state. Our objective is focused on stability analysis of a continuous system with two timevarying delays with an H∞ disturbance attenuation level γ. By exploiting Lyapunov-Krasovski functional and introducing free weighting matrix variables, LMI stability condition have been derived.
A New Voltage Control Method for Single-Phase PWM Inverters Pekik Argo Dahono; Een Taryana
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.5

Abstract

A  new  voltage  control  method  for  single-phase  full-bridge PWM inverters  that having an output LC filter  is proposed in this paper. The proposed voltage  controller has a capability to realize a zero steadystate output voltage error with fast response. The zero steady-state output voltage error is achieved by using a controller that is derived by using the virtual LC resonant circuit. Fast response is obtained by using a virtual resistance  that  is  connected  in  parallel  with  the  filter  capacitor.  The validity of the proposed method is verified by experimental results.
Sorption and Degradation Capacity of Natural Estrogens in Freshwater Environmental System in Japan Reni Desmiarti; Fu-Sheng Li
Journal of Engineering and Technological Sciences Vol. 43 No. 2 (2011)
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.2011.43.2.6

Abstract

The  sorption  and  the  degradation  capacity  of  natural  estrogens  in freshwater  environmental  system  in  Japan  were  performed.  Batch  experiments were examined in water-sediment suspensions using six layers of sediment under aerobic and anaerobic conditions. The results indicated that the water-sediment partition coefficient of E1 (KdE1) was higher than E2 (KdE2). The degradation rate of E1 (kE1) was smaller than E2 (kE2). Under aerobic and anaerobic conditions, E1  was  formed  from  E2.  The  degradation  rate  of  E2  (kE2)  from  the  surface  to bottom of sediment layers was estimated fell in the range from 0.114 to 0.026 h-1 and 0.05 to 0.014 h-1  under aerobic and anaerobic conditions, respectively. 
Comparing Models GRM, Refraction Tomography and Neural Network to Analyze Shallow Landslide Armstrong F. Sompotan; Linus A. Pasasa; Rachmat Sule
Journal of Engineering and Technological Sciences Vol. 43 No. 3 (2011)
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.2011.43.3.1

Abstract

Detailed  investigations  of  landslides  are  essential  to  understand fundamental landslide  mechanisms.  Seismic  refraction  method  has been  proven as a useful geophysical tool for investigating shallow landslides. The objective of this  study  is  to  introduce  a  new  workflow  using  neural  network  in  analyzing seismic  refraction  data  and  to  compare  the  result  with  some  methods;  that  are general  reciprocal  method  (GRM)  and  refraction  tomography.  The  GRM  is effective when the velocity structure is relatively simple and refractors are gently dipping.  Refraction  tomography  is  capable  of  modeling  the  complex  velocity structures  of  landslides.  Neural  network  is  found  to  be  more  potential  in application  especially  in  time  consuming  and  complicated  numerical  methods. Neural network  seem to have the  ability to establish a relationship between an input  and  output  space  for  mapping  seismic  velocity.  Therefore,  we  made  a preliminary attempt to evaluate the applicability of neural network to determine velocity  and  elevation  of  subsurface  synthetic  models  corresponding  to  arrival times.  The  training  and  testing  process  of  the  neural  network  is  successfully accomplished  using  the  synthetic  data.  Furthermore,  we  evaluated  the  neural network  using  observed  data.  The  result  of  the  evaluation  indicates  that  the neural  network  can  compute  velocity  and  elevation  corresponding  to  arrival times. The similarity of those models shows the success of neural network as a new alternative in seismic refraction data interpretation.
A New Fixed Switching Frequency Direct Torque Controlled PMSM Drives with Low Ripple in Flux and Torque Tole Sutikno; Nik Rumzi Nik Idris; Auzani Jidin
Journal of Engineering and Technological Sciences Vol. 43 No. 3 (2011)
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.2011.43.3.2

Abstract

Direct Torque Control (DTC) has gained popularity for development of  advanced  motor  control  due  to  its  simplicity  and  offers  fast  instantaneous torque  and  flux  controls.  However,  the  conventional  DTC  which  is  based  on hysteresis  controller  has  major  drawbacks,  namely  high  torque  ripple  and variable  inverter  switching  frequency.  This  paper  presents  an  improved switching strategy for reducing flux and torque ripples in DTC of PMSM drives; wherein  the  torque  hysteresis  controller  and  the  look-up  table  used  in  the conventional  DTC  are  replaced  with  a  constant  frequency  torque  controller (CFTC)  and  an  optimized  look-up  table,  respectively.  It  can  be  shown  that  a constant switching frequency is established due to the use of the CFTC while the reduction of torque and flux ripples is achieved mainly because of the selection of optimized  voltage  vector (i.e.  with an optimized  look-up  table).  This paper also  will  explain  the  construction  of  DTC  schemes  implemented  using MATLAB-Simulink  blocks.  Simulation  results  were  shown  that  a  significant reduction of flux and torque ripples which is about 90% can be achieved through the proposed DTC scheme. 
A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation Abdul Rajab; Aminuddin Sulaeman; Sudaryatno Sudirham; Suwarno Suwarno
Journal of Engineering and Technological Sciences Vol. 43 No. 3 (2011)
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.2011.43.3.3

Abstract

Mineral  oil  is  known  to  have  a  low  biodegradability  level  and  high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm  oil  with  mineral  type  insulating  liquid  and  silicone  oil.  The  measured parameters  were  breakdown  voltage,  dissipation  factor  (tan  δ),  and  dielectric constant.  Breakdown  voltage  measurement  was  performed  in  accordance  with IEC  156  standard,  whereas,  the  dissipation  factor  and  dielectric  constant measurement  were  conducted  based  on  IEC  60247  standard  test  methods.  The results  showed  that  variations  of  dielectric  properties  of  palm  oil  to  the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation  factors  of  all  tested  oils  were  increased,  while  their  dielectric constants were slightly decreased with the increase of temperature.

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