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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
 65   66   67   68   69 
A Buffer Stock Model to Ensure Price Stabilization and Availability of Seasonal Staple Foods under Free Trade Considerations Wahyudi Sutopo; Senator Nur Bahagia; Andi Cakravastia; T.M.A. Arisamadhi
Journal of Engineering and Technological Sciences Vol. 44 No. 2 (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.2012.44.2.3

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.
A New Obstacle Avoidance Method for Service Robots in Indoor Environments Widodo Budiharto; Ari Santoso; Djoko Purwanto; Achmad Jazidie
Journal of Engineering and Technological Sciences Vol. 44 No. 2 (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.2012.44.2.4

Abstract

The objective of this paper is to propose an obstacle avoidance method for  service  robots  in  indoor  environments  using  vision  and  ultrasonic  sensors. For  this research,  the  service  robot  was  programmed  to  deliver  a  drinking  cup from a specified starting point to the recognized customer. We have developed three main modules: one for face recognition, one for obstacle detection, and one for avoidance maneuvering. The obstacle avoidance system is based on an edg edetection  method  using  information  from  the  landmark  and  planned-path generation. Speed, direction and distance of the moving obstacle are measured using  vision  and  distance  sensors  in  order  for  the robot  to  make  an avoidance maneuver. Algorithms for obstacle avoidance are proposed and a new geometric model is introduced for making good avoidance maneuvers. The main aim of this research is to provide a complete mechanism for obstacle avoidance by vision based service robots, where common obstacle avoidance methods, such as PVM, do  not  provide  such  a  feature.  We  present the results  of  an  experiment  with  a service  robot  in  which  the  proposed  method  was  implemented,  after  which  its performance is evaluated.
Linear Parameter-Varying Versus Linear Time-Invariant Reduced-Order Controller Design for Turboprop Aircraft Dynamics Widowati Widowati; Bambang Riyanto; Hari Muhammad
Journal of Engineering and Technological Sciences Vol. 44 No. 2 (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.2012.44.2.5

Abstract

The  applicability  of  parameter-varying  reduced-order  controllers  to aircraft  models  is  proposed.  A  generalization  of  the  balanced  singular perturbation method of the linear time-invariant (LTI) system was used to reduce the order of  the  linear parameter-varying (LPV) system. Based on the reducedorder model, a  low-order  LPV  controller  was  designed  using  the H∞ synthesis technique.  The  performance  of  the  reduced-order  controller  was  examined  by applying  it  to  the  lateral-directional  control  of  a  20th-order  aircraft  model. Furthermore, the time responses of the closed-loop system with  several reducedorder LPV controllers and  a  reduced-order LTI controller  were  compared.  The simulation results  show that an  ,  8th -order LPV controller can maintain stability and  provide  the  same  level  of  closed-loop  system  performance  as  a  full-order LPV  controller.  This  was  not  the  case  with  the  reduced-order  LTI  controller, which  cannot  maintain  stability  and  performance  for  all  allowable  parameter trajectories.
Estimation of Slip Distribution of the 2007 Bengkulu Earthquake from GPS Observations Using the LeastSquares Inversion Method Moehammad Awaluddin; Irwan Meilano; Sri Widiyantoro
Journal of Engineering and Technological Sciences Vol. 44 No. 2 (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.2012.44.2.6

Abstract

Continuous  Global  Positioning  System  (GPS)  observations  showed significant  crustal  displacements  as  a  result  of  the  Bengkulu  earthquake occurring on September 12, 2007. A maximum horizontal displacement of 2.11 m was observed at PRKB station, while the vertical component at BSAT station was lifted up with a maximum of 0.73 m, and the vertical component at LAIS station had subsided  "“0.97 m. Adding more constraints on the inversion for the Bengkulu earthquake slip distribution inferred from GPS observations can help solve  the  underdetermined  least-squares  inversion.  Checkerboard  tests  were performed  to  help  conduct  the  weighting  for  constraining  the  inversion.  The inversion calculation yielded an optimal value for the slip distribution by giving the smoothing constraint a weight of 0.001 and the slip constraint a weight of = 0 at the edge of the earthquake rupture area. The maximum co-seismic slip of the optimal inversion calculation was 5.12 m at the lower area of PRKB station and BSAT station. The seismic moment calculated from the optimal slip distribution was 7.14 x 1021 Nm, which is equivalent to a magnitude of 8.5.
Siloxane based Organic-Inorganic Hybrid Polymers and their Applications for Nanostructured Optical/Photonic Components Rahmat Hidayat; Widiyanta Gomulya; Pina Pitriana; Ryan Irmansyah; Rany Miranti; Herman Herman; Sahrul Hidayat; Fitrilawati Fitrilawati; Akihiko Fujii; Masanori Ozaki
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.2012.44.3.1

Abstract

We have studied the preparation of organic-inorganic hybrid polymer precursors  by  sol-gel  technique  and  their  utilization  for  nanostructured  optical components for photonic applications. The gel polymer precursors were prepared from  siloxane  modified  by  polymerizable  acrylate  groups,  which  can  be processed  further  by  photopolymerization  process.  Molecular  structure characterizations by means of the FTIR measurements indicate the conversion of C=C  bonds  into  C-C  bonds  after  photopolymerization.  This  bond  co nversion produces  high  cross-linking  between  the  organic  and  inorganic  moieties, resulting  in  thermally  stable and chemically resistant thin polymer layer which provide  unique  advantages  of  this  material  for  particular  optical/photonic applications.  By  employing  laser  interference  technique,  gratings  with periodicity between 400-1000 nm have been successfully fabricated. Application of  those  sub-micron  periodicity  of  grating  structure  as  active  elements  in optically  pumped  polymer  laser  system  and  Surface Plasmon Resonance  (SPR) based  measurement  system  have  been  also  explored.  The  experimental  results therefore  also  show  the  potential  applications  of  this  hybrid  polymer  as  a building material for micro/nano-photonics components. 
Confinement of Reinforced-Concrete Columns with NonCode Compliant Confining Reinforcement plus Supplemental Pen-Binder Anang Kristianto; Iswandi Imran; Made Suarjana; Ivindra Pane
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.2012.44.3.2

Abstract

Abstract.  One  of  the  important  requirements  for  earthquake  resistant  building related  to  confinement  is  the  use  of  seismic  hooks  in  the  hoop  or  confining reinforcement  of  reinforced-concrete  column  elements. However, installation of a  confining  reinforcement  with  a  135-degree  hook  is  not  easy.  Therefore,  in practice, many construction workers apply a confining reinforcement with a  90-degree  hook  (non-code  compliant).  Based  on  research  and  records  of  recent earthquakes  in  Indonesia,  the  use  of  a  non-code  compliant  confining reinforcement  for  concrete  columns  produces  structures  with  poor  seismic performance.  This paper  presents a study  that  introduces  an additional element that is expected to improve the effectiveness of concrete columns confined with a non-code compliant  confining reinforcement. The additional element, named a pen-binder,  is   used to keep the  non-code compliant  confining reinforcement in place. The effectiveness of this element  under pure axial concentric loading  was investigatedcomprehensively.The  specimens  tested  in  this  study  were  18 concrete columns,with a cross-section of 170 mm x 170 mm and a height of 480 mm. The main test variables were the material type of the  pen-binder, the angle of  the  hook,  and  the  confining  reinforcement  configuration.The  test  results indicate  that  adding  pen -binders  can  effectively  improve  the  strength  and ductility of the column specimens confined with a non-code compliant  confining reinforcement. 
The Effect of Ozonation Process on Bromide-Containing Groundwaters in Bandung Area and Its Surroundings Mindriany Syafila; Sukandar Sukandar; Eric Haryanto
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.2012.44.3.3

Abstract

Disinfection process was applied as the last step of the water treatment to kill pathogenic bacteria in  the  water. However,  according to  several studies, the  ozonation  disinfection  process could form undesired by-products.  One of the by-products  potentially  affecting human life is bromate  produced from bromide ionic-containing  water. This study was carried out to examine the effect of raw water  characteristics  and  pH  on  bromate  formation.  Also,  the  performance  of bromate formation for a period of exposure time was analyzed. Raw waters taken from four different areas around Bandung were exposed to ozone introduced to a reactor with a flow rate of 2 L/min. The pH of the raw waters varied from 4, 7 to 10.  The  results  show  that  there  was  no  evidence  of  an  initial  bromide  ion concentration,  whereas  a  change  in  pH  value  gives  a  significantly  different outcome. In  acidic condition  (pH of 4) the  bromate  formation tends to decrease, whereas  when  the  pH  value  increases  to  a  pH  of  10,  the  bromate  formation increases.  Therefore, for drinking water  with a  neutral pH,  when bromide ions are  detected  in  the  raw  water,  the  drinking  water  may  be  toxic  due  to  the presence of bromate.
Experimental Study of Confined Low-, Medium- and High-Strength Concrete Subjected to Concentric Compression Antonius Antonius; Iswandi Imran
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.2012.44.3.4

Abstract

An  experimental  study  of  23  low-,  medium-  and  high-strengthconcrete  columns is presented in this paper. Square-confined concrete columns without  longitudinal  reinforcement  were  designed,  and  tested  under  concentric axial  compression.  The  columns  were  made  of  concrete  with  a  compressive strength ranging between 30 MPa and 70 MPa. The test parameters in the study are  concrete  compressive  strengths  and  confining  steel  properties,  i.e.  spacing, volumetric  ratios  and  configurations.  The  effects  of  these  parameters  on  the strength  and  ductility  of  square-confined  concrete  were  evaluated.  Of  the specimens tested in this study, the columns made with higher-strength concrete produced less strength  enhancement and ductility than those with lower-strength concrete.  The  steel  configurations  were  found  to  have  an  important  role  in governing  the  strength  and  ductility  of  the  confined  high-strength  concrete. Moreover,  several  models  of  strength  enhancement  for  confined  concrete available  in  the  literature  turned  out  to  be  quite  accurate  in  predicting  the experimental results.
Miscibility Development Computation in Enhanced Oil Recovery by Flare Gas Flooding Tjokorde Walmiki Samadhi; Utjok W.R. Siagian; Angga P. Budiono
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.2012.44.3.5

Abstract

The use of flare gas as injection gas in miscible gas flooding enhanced oil  recovery  (MGF-EOR)  presents  a  potential  synergy  between  oil  production improvement  and  greenhouse  gases  emission  mitigation.  This  work  is  a preliminary evaluation of the feasibility of miscible flare gas injection based on phase behavior computations of  a model oil (43% n-C5H12 : 57% n-C16H34) and a model flare gas (91% CH4  : 9% C2H6). The computations employed the multiple mixing-cell  model  with  Peng-Robinson  and  PC-SAFT  equations  of  state,  and compared the minimum miscibility pressure (MMP) value in the cases of flare gas  injection  and  CO2  injection.  For  CO2  injection,  both  equations  of  state produced  MMP  values  close  to  the  measured  value  of  10.55  MPa.  Flare  gas injection MMP values were predicted to be 3.6-4.5 times those of CO2  injection. This very high MMP implies high gas compression costs, and may compromise the  integrity  of  the  reservoir.  Subsequent  studies  shall  explore  the  gas -oil miscibility  behavior  of  mixtures  of  flare  gas  with  intermediate  hydrocarbon gases and  CO2,  in  order to  identify  a suitable approach for rendering flare  gas feasible as an injection gas in MGF-EOR.
The Power Consumption Performance of an Orbiting Screw Solid-Solid Mixer Semuel Pati Senda; Renanto Renanto; Achmad Roesyadi; Wahono Sumaryono; Yazid Bindar
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.2012.44.3.6

Abstract

In this work we have investigated mixing in a modified orbiting screw mixer  (MOSM)  designed  for  solid-solid mixing.  Mixing  was  carried  out  using urea powder and natural zeolite powder (UZ) of three varying particle sizes (50-60, 60-80 and 80 mesh). Power consumption was calculated from the measured torque of orbit and screw, obtained from computerized records. It was found that the  mixing  process  in  the  modified  orbiting  screw  mixer  with  air  injection required a lower power consumption for each particle-size group when compared to mixing without air injection. With UZ mixing in MOSM with  air injection, the lowest E was obtained for  the 60-80 mesh particle-size group  (4,297 Joule/kg-1),whereas when mixing without  air injection, the value was  10,296 J/kg. The best mixing  operation in this experiment was achieved at NFr  =  1.18x10-3 and in the range  of  values  NRe≈  8.77x107 to  2.63x108.  Moreover,  in this  study,  we  have developed  an  equation  to  estimate the  power  consumption required  for  mixing and determined its correlation with dimensionless numbers.

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