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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
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Algorithms of Clustering and Classifying Batik Images Based on Color, Contrast and Motif Moertini, Veronica S.; Sitohang, Benhard
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 (2121.037 KB) | DOI: 10.5614/itbj.eng.sci.2005.37.2.5

Abstract

An interactive system could be provided for batik customers with the aim of helping them in selecting the right batiks. The system should manage a collection of batik images along with other information such as fashion color type, the contrast degree, and motif. This research aims to find methods of clustering and classifying batik images based on fashion color, contrast and motif. A color clustering algorithm using HSV color system is proposed. Two algorithms for contrast clustering, both utilize wavelet, are proposed. Six algorithms for clustering and classifying batik images based on group of motifs, employing shape- and texture-based techniques, are explored and proposed. Wavelet is used in image pre-processing, Canny detector is used to detect image edges. Experiments are conducted to evaluate the performance of the algorithms. The result of experiments shows that fashion color and contrast clustering algorithms perform quite well. Three of motif based clustering and classification algorithms perform fairly well, further work is needed to increase the accuracy and to refine the classification into detailed motif.
Comparative Study on Solar Collector’s Configuration for an Ejector-Refrigeration Cycle Senjaya, Raffles; Astina, I Made
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 (434.828 KB) | DOI: 10.5614/itbj.eng.sci.2008.40.1.4

Abstract

Solar collector’s configuration plays important role  on solar-powered refrigeration systems  to work as heat source for generator . Three types of solar collector consisting  of flat plate, evacuated tube, and compound parabolic solar collectors  are  compared  to  investigate  their  performances.  The  performances consist of the behavior of heat which can be absorbed by the collectors, heat loss from  the  collectors  and outlet temperature of working fluid at several slopes of the  solar  collectors.  The  new  accurate  analysis  method  of  heat  transfer  is conducted  to  predict  the  performance  of  the  solar  collectors.  The  analysis  is based  on  several  assumptions,  i.e.  sky  condition  at  Bandung  is  clear  and  not raining from 08.00 until 17.00 and thermal resistance at cover and absorber plate is  negligible. The numerical calculation results confirm that performance of  the evacuated  tubes  solar  collector  at  the  same  operating  conditions  is higher  than the  others.  For  the  case  of  an  evacuated-tubes  solar  collector  system  with aperture area of 3.5 m2, the maximum heat which can be absorbed is 3992  W for the highest solar intensity  of  970 W/m2 at 12.00  with  horizontal position of  the solar  collector.  At  this  condition,  the  highest  outlet  temperature  of  water  is 347.15 K with mass flow rate 0.02 kg/s and inlet temperature 298 K.
The Effects of Cr and Mo on the Microstructure and Mechanical Properties of As-Cast TiAl Alloys Usman, Husni; Noor, Ahmad Fauzi Mohd.; Astrawinata, Rizal
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 (2730.119 KB) | DOI: 10.5614/j.eng.technol.sci.2013.45.3.6

Abstract

The effect of the alloying elements of Cr and Mo on the microstructure and mechanical properties of as-cast TiAl alloys produced by a locally made arc-melting furnace was studied. X-ray diffraction (XRD) was used to identify the phases present in the samples. The microstructure of the TiAl samples was characterized using scanning electron microscopy combined with energy dispersive spectroscopy (EDS). Compression tests were carried out at room temperature using an Instron servohydraulic testing machine. The results show that the Ti-48Al alloy exhibited a duplex microstructure, whereas with the addition of Cr a nearly lamellar microstructure was observed in Ti-48Al-2Cr and with the addition of both Cr and Mo also in Ti-48Al-2Cr-2Mo. The hardness values increased slightly as compared to the Ti-48Al alloy with the addition of the alloying elements. The presence of Cr in Ti-48Al-2Cr resulted in a slight increase in compressive fracture strain. The as-cast Ti-48Al-2Cr-2Mo alloy produced a higher yield strength and fracture strain in compression as compared to the other as-cast TiAl alloys. On the fracture surfaces of the as-cast TiAl alloys, mixed brittle transgranular and interlamellar fracture modes were predominantly observed.
An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine Hantoro, Ridho; Utama, I.K.A.P; Erwandi, Erwandi; Sulisetyono, Aries
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 (593.016 KB) | DOI: 10.5614/itbj.eng.sci.2011.43.1.3

Abstract

Vertical-axis hydrokinetic turbines with fixed pitch blades typically suffer from poor starting torque, low efficiency and shaking due to large fluctuations in both radial and tangential force with azimuth angle. Maximizing the turbine power output can be achieved only if the mechanism of generation of the hydrodynamic force on the blades is clearly identified and tools to design high-performance rotors are developed.This paper describes an initial experimental investigation to understand more of the performance on vertical-axis turbine related to the effect of fixed-pitch and passive variable-pitch application using airfoil NACA 0018. Comparative analysis according to aspects of rotation and tip speed ratios was discussed. Information regarding the changes of foil position in passive variable-pitch during rotation at a limited range of flow velocity variations test was obtained and analyzed. 
Adjustment of Daily Activities: the Influence of Smartphone Adoption on the Travel Pattern of Mobile Professionals in the Greater Jakarta Area Christin, Gloriani Novita; Tamin, Ofyar Z.; Santosa, Idwan; Miharja, Miming
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 (703.367 KB) | DOI: 10.5614/j.eng.technol.sci.2014.46.4.4

Abstract

The  swift  augmentation  in  the  adoption  of  smartphones,  the  gadget that  resulted  from  the  convergence  of  Information  and  Communication Technology  (ICT),  potentially  transforms  peoples  life  in  myriad  dimensions. One  potential  change  induced  by  smartphones,  is  how  people  restructure  their daily agenda and consecutively influence their travel pattern. To understand it, this study theoretically reviews  mobile professional work, smartphone adoption, and how people conduct their mobile interaction, planning and execution of daily activities. Mobile professionals, the  cohort of professionals  that spend more than 20% of their total working time moving  around out  of  their work environment; they  are  important  beneficiaries  of  smartphones  and   have  been  chosen  as  the target of  this  study. Empirical results of mobile professionals´ experiences in the Greater Jakarta Area are presented at this juncture. Furthermore, their adjustment of  activities  as  a  dynamic  response  to  receiving  extensive  information  via smartphones  is  also  analysed.  The  results  indicate  that  there  is  a  strong adjustment  of  daily  activities  by  mobile  professionals.  Through  those  changes, the transformation of daily travel patterns  related to the activity is  also  brought about by the use of this high-end ICT contrivance.
A New Obstacle Avoidance Method for Service Robots in Indoor Environments Budiharto, Widodo; Santoso, Ari; Purwanto, Djoko; Jazidie, Achmad
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 (517.279 KB) | 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.
Influence of Constraining Barrier on the 5th Lumbar and 1st Sacral joint Compressive Force during Manual Lifting Budihardjo, I.; Derrick, T. R.
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 (260.297 KB) | DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.6

Abstract

The purpose of this study was to examine the mechanical stresses on the lower back as the response of different heights of constraining barrier. Ten male subjects lifted a load from the floor to the knuckle height under the non-constrained and the constrained conditions with 4 different heights of constraining barrier (80%, 100%, 120% and 140% of knee height). The constrained condition was defined as the condition where a load was placed on the floor behind a certain level of bar. When lifting of the constrained conditions, subjects significantly increased the peak compressive forces at L5/S1 compared to the non-constrained (3868.8 ± 527.5 N, 4175.0 ± 486.0 N, 4162.4 ± 462.3 N, 4136.0 ± 553.1 N, 4079.4 ± 468.9 N for 0%, 80%, 100%, 120% and 140% barrier height conditions respectively). The subjects moved the load further from L5/S1 in the horizontal direction when lifting during the constrained conditions. While lifting during the constrained conditions subjects generated an increase in the sacral angle and a decrease of the knee flexion. The peak compressive forces at L5/S1 showed a statistically significant quadratic trend. However, the magnitude of the difference of peak compressive forces during the constrained conditions was small.
Laboratory Experiments on Enhanced Oil Recovery with Nitrogen Injection Siregar, S; Hidayaturobbi, A. D.; Wijaya, B. A.; Listiani, S N; Adiningrum, T; Irwan, Irwan; Pratomo, A I
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 (114.166 KB) | DOI: 10.5614/itbj.eng.sci.2007.39.1.2

Abstract

Based on previous studies, nitrogen injection could recover oil up to 45-90% of initial reserves. Although this method has a very good ability to produce oil, sometimes the operation pressure is higher than leak off formation pressure. In this study, operation pressure used a low pressure to solve this problem under immiscible process. Objective of this study is to determine the effect of injection pressure and displacement rate on oil recovery performance of continuous one dimensional nitrogen gas injection with a slim tube apparatus. The effect of nitrogen gas-oil contact on the gas composition was investigated using Gas Chromatograph Mass Spectrometer apparatus. In the experiments, nitrogen gas was injected into an oil sample of 38.5 oAPI gravity at various rates: 20 cc/hr, 30 cc/hr and 36.66/hr under 1500 psi pressure, and then at 20 cc/hr undr 2500 psi pressure. The results showed that an increase in injection rate increased oil recovery factor. The recovery factor lies between 40-54% of original oil in place. Gas analysis before injection and at the injection outlet showed a change of composition. when oil was contacted by nitrogen, indicating that some molecular mass transfer had taken place.
CH4 Emission Model from Bos Primigenius Waste in Fish-Water: Implications for Integrated Livestock-Fish Farming Systems Okeniyi, Joshua O.; Ogunsanwo, Adedamola O.; Odiase, Nosadeba W.; Obiajulu, Uchechukwu E.; Okeniyi, Elizabeth T.
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 (218.125 KB) | 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.
Tolerance Stack Analysis in Francis Turbine Design Djodikusumo, Indra; Suherman, Koko; Oken, Paskalis Bowo A.
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 (319.831 KB) | DOI: 10.5614/itbj.eng.sci.2010.42.1.6

Abstract

The  tolerance  stacking  problem  arises  in  the  context  of  assemblies from  interchangeable  parts  because  of  the  inability  to  produce  or  to  join  parts exactly  according  to  nominal  dimensions.  Either  the  relevant  part’s  dimension varies around some nominal values  from part to part or the act of assembly that leads  to  variation.  For  example,  as  runner  of  Francis  turbine  is  joined  with turbine shaft via mechanical lock,  there is not only variation in the diameter of runner  and the concentricity between the runner  hole  and  turbine  shaft, but also the  variation in  concentricity  between  the  outer  parts  of  runner  to runner hole. Thus,  there  is  the  possibility  that  the  assembly  of  such  interacting  parts  won’t function  or  won’t  come  together  as  planned.   Research  in  this  area  has  been conducted and 2 mini hydro Francis turbines (800 kW and 910 kW) have been designed and manufactured for San Sarino and Sawi Dago 2 in Central Sulawesi. Experiences  in  analyzing  the  tolerance  stacks  have  been  documented.  In  this paper it will be demonstrated how the requirements of assembling performance are derived to be the  designed    tolerances  of each interacting component, such  a way that the assembling would be functioning and come together as planned.

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