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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 1,249 Documents
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Topographic data generated from Radarsat Images Over West Kalimantan, Indonesia Ismullah, Ishak Hanafiah; Nurtyawan, Rian
Journal of Engineering and Technological Sciences Vol 37, No 2 (2005)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1428.878 KB) | DOI: 10.5614/itbj.eng.sci.2005.37.2.3

Abstract

 Indonesia is a tropical country which has dominant cloud coverage, and some of the area has cloud cover almost all year long. Mapping by optical sensors, especially with Photogrammetric method shows a very good result, but the main constraint is cloud cover conditions, and this was the weakness point of this method.This study describe the technique for deriving Topographic data from Radarsat Synthetic Aperture Radar stereo image pair and apply it to an image pair over West Kalimantan, Indonesia. This paper contains also brief discussion of the use of stereo SAR to derive Digital Elevation Model, the site condition and the source of validation data. The result shows that Radarsat data recommended only for 1 : 100.000 or smaller.
Leakage Current Waveforms and Arcing Characteristics of Epoxy Resin for Outdoor Insulators under Clean and Salt Fogs Suwarno, Suwarno; Ardianto, S. K.
Journal of Engineering and Technological Sciences Vol 40, No 1 (2008)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (526.468 KB) | DOI: 10.5614/itbj.eng.sci.2008.40.1.3

Abstract

Ceramic  outdoor  insulators  have  been  used  in  high  voltage transmission lines since long time ago. Due to superiority in their resistance to pollution, recently, polymeric outdoor insulators are widely used. Epoxy resin is one  polymer  which  shows  good  properties  for  outdoor  insulation.  During service,  outdoor  insulators  may severe a certain degree of pollution  which may reduce  their  surface  resistance.  Leakage  current  (LC)  usually   increase  and degradation  may  take  place.  This  paper  reports  experimental  results  on  the leakage current  waveforms and arcing characteristics of epoxy resin  under clean and salt fog. The samples used are blocks of epoxy resin with dimension of 250 x  50  x  20  mm3 .  The  samples  were  put  in  a  test  chamber  with  dimension  of 900x900x1200 mm3 with controllable humidity  and pollution conditions. Clean and  salt  fog  were  generated  according  to  IEC  60-1  and  507.  The  arcing experiment  was  done  with  incline  plane  test  in  accordance  with  IEC  587.  AC voltage  in the range from 5 kV to 50 kV with frequency of 50 Hz  was applied. The LC waveforms  up to flash over  were measured. The magnitudes as well as harmonic  content  of  the  LC  were  analyzed.   The  correlation  between  LC waveforms  and  dry  band  arching  phenomenon  was  elaborated.  Visual observation  of  the  arc  on  the  sample  surfaces  was  observed  using  a  video camera. Experimental results indicated that LC magnitude on clean  samples was slightly affected by humidity (RH). However, under salt fog, RH greatly affected the LC magnitude. The flashover voltage of clean samples under salt fog reduced significantly  for  fog  conductivity  of  more  than  1.2  mS/cm.  Kaolin-polluted samples under salt fog showed an Ohmic behaviour. The LC magnitude was high and a large discrepancy of LC magnitude was observed for high applied voltage of  larger  than  25  kV.  The  largest  LC  magnitude  was  observed  on  salt-kaolin polluted samples under clean fog at high RH. LC waveforms analysis indicated that in general LC waveforms were distorted from sinusoidal. For clean samples under clean fog, THD  of LC decreased with RH but slightly increased with the applied voltage. Large distortion at the peak of LC waveform  was observed on kaolin  polluted  sample  under  salt  fog  of  3.6  mS/cm  and  high  RH  and  high applied voltage. This correlates with corona arc on the sample surface. Similar behaviour  was  observed  on  kaolin-salt  polluted  samples  under  clean  fog. Tracking arc experiment indicated that arc length LC magnitude and arc intensity increased with the pollutant conductivity. The THD also significantly increased with  pollutant  conductivity.  At  conductivity  of  less  than  0.6  mS/cm  the unsymmetrical  LC  waveforms  were  obtained.  However,  symmetrical  LC waveforms were observed for conductivity of 0.9 and 1.2 mS/cm. The change of LC magnitude and waveform at different condition of samples may be useful for the diagnostics of insulator condition.
New Correlations for Coal and Biomass Pyrolysis Performances with Coal-Biomass Type Number and Temperature Bindar, Yazid
Journal of Engineering and Technological Sciences Vol 45, No 3 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (906.999 KB) | DOI: 10.5614/j.eng.technol.sci.2013.45.3.5

Abstract

The pyrolysis of coal and biomass is generally reported as the mass yield of released chemicals at various temperatures, pressures, heating rates and coal or biomass type. In this work, a new coal-biomass type number, NCT, is introduced. This number is constructed from the mass fractions of carbon, hydrogen, and oxygen in the ultimate analysis. This number is unique for each coal or biomass type. For 179 different species of coal and biomass from the literature, the volatile matter mass yield can be expressed by the second order polynomial function ln(NCT). This unique correlation allows the effects of the temperature and heating rate on the volatile yield YVY for coal and biomass to be empirically correlated as well. The correlation for the mass fraction of each chemical component in the released volatile matter correlation is obtained from the YVY correlation. The weight factor for some of the components is constant for the variation of NCT, but not for others. The resulted volatile matter and yield correlations are limited to atmospheric pressure, very small particles (less than 0.212 mm) and interpreted for wire-mesh pyrolysis reactor conditions and a nitrogen gas environment.
The All-DQ-Domain EMTP Sianipar, Gibson H.M.
Journal of Engineering and Technological Sciences Vol 43, No 1 (2011)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (302.873 KB) | DOI: 10.5614/itbj.eng.sci.2011.43.1.2

Abstract

This paper presents an improvement to dq-domain method of calculating electromagnetic transients. The proposed methodology works on dq-domain model for all components of the power system and during all time iterations.  This is a new direction distinct from the old one where the network is invariably modeled in phase-domain. By modeling the network in dq-domain there is no more problem of interfacing machine to network as usually met in the existing method as machine is modeled invariably in dq-domain. Besides eliminating the time consuming transformation procedure between dq-domain to phase-domain or visa versa the new method is able now to fully exploit the infinite stability region of the trapezoidal rule of integration. The prediction/correction procedure of the conventional dq-domain method, which is notoriously known limiting the stability region, is no longer required. Comparing simulations using the new method and ATP, one of the conventional dq-domain version, show perfect conformity for small time step. For long time step while ATP is failing, the new method still converges accurately up to Nyquist’s interval. 
Identifying Contractors’ Planned Quality Costs in Indonesian Construction Projects Marzuki, Puti F.; Wisridani, M.
Journal of Engineering and Technological Sciences Vol 46, No 4 (2014)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (714.028 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.4.2

Abstract

In  a very competitive construction industry, quality costs have to be measured  to  be  able  to  identify  potential  quality  problem  areas  and  to  focus attention  on  work  output  improvement  opportunities.  The  awareness  of contractors on the importance of quality costs could be reflected in the extent of their  quality  costs  planning.  This  paper  presents  an  identification  of  planned quality  costs  in  three  construction  projects  executed  by  two  large  Indonesian contractors,  a  state-owned  company  and  a  private  company  in  Jakarta.  The objective is to enable the contractors to elaborate their quality costs planning and thereby improve their work output based on the findi ngs. Quality  costs  are  first grouped into  three  categories: prevention, appraisal,  and  failure  costs.  Based on the  works  of  previous  researchers,  a  list  of  quality  management  activities  that should be covered in each quality costs category is then created. The contractors’ planned quality costs data  for each category are  identified and  collected through interviews  and  questionnaire  surveys  that   refer  to  the  list.  Quality  costs  are expressed  as  a  percentage  of  contract  value.  It  is  revealed  that  although  large contractors  already  have  certain  knowledge  on  quality  costs  in  construction projects,  these costs are  not planned in a structured way  through an analysis of systematic  quality  costs  records.  Through  cost  categorization  it  is  also  shown that higher prevention and appraisal costs lead to lower failure costs.  It is then concluded  that  a  lot  of  work  is  still  to  be  done  by  the  contractors  to  set  up  a quality  costs  recording  system  which  can  serve  as  a  basis  for  their  quality improvement planning.
A Buffer Stock Model to Ensure Price Stabilization and Availability of Seasonal Staple Foods under Free Trade Considerations Bahagia, Senator Nur; Cakravastia, Andi; Arisamadhi, T.M.A.; Sutopo, Wahyudi
Journal of Engineering and Technological Sciences Vol 44, No 2 (2012)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (361.774 KB) | DOI: 10.5614/itbj.eng.sci.2012.44.2.3

Abstract

Price  volatility  and  scarcity  have  become  a  great  problem  in  the distribution  system  of  seasonal  staple  foods  produced  by  the  agricultural industry.  There  is  a  salient  supply  disparity  during  the  harvest  and  planting seasons.  This  condition  could  cause  disadvantages  to  stakeholders  such  as producers,  wholesalers,  consumers,  and  government.  This  paper  proposes  a buffer  stock  model  under  free-trade  considerations  to  substitute  quantitative restrictions  and  tariffs  with  an  indirect  market  intervention   instrument.  This instrument  was  developed  using  a  buffer  stock  scheme  in  accordance  with  a  warehouse receipt system  (WRS) and  a  collateral management system.  A  public service  institution  for  staple  food  buffer  stock   (BLUPP)  is  proposed  as  the wholesaler’s competitor,  with  as main responsibility   to ensure price stabilization and availability of staple food. Multi-criteria decision-making is formulated as a single  objective  mixed  integer  non-linear  programming  (MINLP)  model.  The results  shows  that  the  proposed  model  can  be  applied  to  solve  the  distribution problem  and  can  give  more  promising  outcomes  than  its  counterpart,  direct market intervention.
Studying Landslide Displacements in Megamendung (Indonesia) Using GPS Survey Method Abidin, Hasanuddin Z.; Andreas, H.; Gamal, M.; Surono, Surono; Hendrasto, M.
Journal of Engineering and Technological Sciences Vol 36, No 2 (2004)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1502.349 KB) | DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.2

Abstract

Landslide is one of prominent geohazards that frequently affects Indonesia, especially in the rainy season. It destroys not only environment and property, but usually also causes deaths. Landslide monitoring is therefore very crucial and should be continuously done. One of the methods that can have a contribution in studying landslide phenomena is repeated GPS survey method. This paper presents and discusses the operational performances, constraints and results of GPS surveys conducted in a well known landslide prone area in West Java (Indonesia), namely Megamendung, the hilly region close to Bogor. Three GPS surveys involving 8 GPS points have been conducted, namely on April 2002, May 2003 and May 2004, respectively. The estimated landslide displacements in the area are relatively quite large in the level of a few dm to a few m. Displacements up to about 2-3 m were detected in the April 2002 to May 2003 period, and up to about 3-4 dm in the May 2003 to May 2004 period. In both periods, landslides in general show the northwest direction of displacements. Displacements vary both spatially and temporally. This study also suggested that in order to conclude the existence of real and significant displacements of GPS points, the GPS estimated displacements should be subjected to three types of testing namely: the congruency test on spatial displacements, testing on the agreement between the horizontal distance changes with the predicted direction of landslide displacement, and testing on the consistency of displacement directions on two consecutive periods.
Leak Detection Modeling and Simulation for Oil Pipeline with Artificial Intelligence Method Sukarno, Pudjo; Sidarto, Kuntjoro Adji; Trisnobudi, Amoranto; Setyoadi, Delint Ira; Rohani, Nancy; Darmadi, Darmadi
Journal of Engineering and Technological Sciences Vol 39, No 1 (2007)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (366.24 KB) | DOI: 10.5614/itbj.eng.sci.2007.39.1.1

Abstract

Leak detection is always interesting research topic, where leak location and leak rate are two pipeline leaking parameters that should be determined accurately to overcome pipe leaking problems. In this research those two parameters are investigated by developing transmission pipeline model and the leak detection model which is developed using Artificial Neural Network. The mathematical approach needs actual leak data to train the leak detection model, however such data could not be obtained from oil fields. Therefore, for training purposes hypothetical data are developed using the transmission pipeline model, by applying various physical configuration of pipeline and applying oil properties correlations to estimate the value of oil density and viscosity. The various leak locations and leak rates are also represented in this model. The prediction of those two leak parameters will be completed until the total error is less than certain value of tolerance, or until iterations level is reached. To recognize the pattern, forward procedure is conducted. The application of this approach produces conclusion that for certain pipeline network configuration, the higher number of iterations will produce accurate result. The number of iterations depend on the leakage rate, the smaller leakage rate, the higher number of iterations are required. The accuracy of this approach is clearly determined by the quality of training data. Therefore, in the preparation of training data the results of pressure drop calculations should be validated by the real measurement of pressure drop along the pipeline. For the accuracy purposes, there are possibility to change the pressure drop and fluid properties correlations, to get the better results. The results of this research are expected to give real contribution for giving an early detection of oil-spill in oil fields.
Modification of Attenuation Rate in Range Normalization of Echo Levels for Obtaining Frequency-dependent Intensity Data from 0.6MHz and 1.0MHz Devices Poerbandono, R.; Suprijo, Totok
Journal of Engineering and Technological Sciences Vol 45, No 2 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (457.688 KB) | 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.
Geochemical Tracer in Coral as a Sea Surface Temperature Proxy: Records from Jukung Coral Cahyarini, S. Y.; Zinke, J.
Journal of Engineering and Technological Sciences Vol 42, No 1 (2010)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (272.825 KB) | DOI: 10.5614/itbj.eng.sci.2010.42.1.5

Abstract

Sr/Ca  has been analyzed from coral core from the Seribu Islands  reef complex  i.e  Jukung  Island.  SST  from  ERSST  dataset  and  air  temperature measured at Jakarta is used for Sr/Ca calibration. The results show that Jukung Island  coral  Sr/Ca  correlates  better  with  SST  than  with  air  temperature.  A comparison  between  the  Sr/Ca  records  with  the  Nino  3.4  index  shows  that Jukung  coral  sites  indicate  warming  sea  surface  temperatures  during  the beginning  of El Nino  events followed by cooling temperatures at the end of El Nino years.

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