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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
 62   63   64   65   66 
Closed Form Solution of Synchronous Machine Short Circuit Transients Gibson H.M. Sianipar
Journal of Engineering and Technological Sciences Vol. 42 No. 1 (2010)
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.2010.42.1.7

Abstract

This  paper  presents  the  closed  form  solution   of  the  synchronous machine  transients undergoing short circuit. That analytic formulation has been derived  based  on  linearity  and  balanced  conditions  of  the  fault.  Even  though restrictive, the proposed method will serve somehow or other as a new resource for  EMTP  productivity.  Indisputably  superior, the  closed-form  formulation has some  features  inimitable  by  discretization  such  as  continuity,  accuracy  and absolute numerical stability. Moreover, it enables us to calculate states at one specific  instant  independent  of  previous  states  or  a  snapshot,  which  any discretization methods cannot do.
Behavior of Shear Link of WFSection with Diagonal Web Stiffener of Eccentrically Braced Frame (EBF) of Steel Structure Yurisman Yurisman; Bambang Budiono; Muslinang Moestopo; Made Suarjana
Journal of Engineering and Technological Sciences Vol. 42 No. 2 (2010)
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.2010.42.2.1

Abstract

This paper presents results of numerical and experimental study of shear link behavior, utilizing diagonal stiffener on web of steel profile to increase shear link performance in an eccentric braced frame (EBF) of a steel structure system. The specimen is to examine the behavior of shear link by using diagonal stiffener on web part under static monotonic and cyclic load. The cyclic loading pattern conducted in the experiment is adjusted according to AISC loading standards 2005. Analysis was carried out using non-linear finite element method using MSC/NASTRAN software. Link was modeled as CQUAD shell element. Along the boundary of the loading area the nodal are constraint to produce only one direction loading. The length of the link in this analysis is 400mm of the steel profile of WF 200.100. Important parameters considered to effect significantly to the performance of shear link have been analyzed, namely flange and web thicknesses, thickness and length of web stiffener, thickness of diagonal stiffener and geometric of diagonal stiffener. The behavior of shear link with diagonal web stiffener was compared with the behavior of standard link designed based on AISC 2005 criteria. Analysis results show that diagonal web stiffener is capable to increase shear link performance in terms of stiffness, strength and energy dissipation in supporting lateral load. However, differences in displacement ductility's between shear links with diagonal stiffener and shear links based on AISC standards have not shown to be significant. Analysis results also show thickness of diagonal stiffener and geometric model of stiffener to have a significant influence on the performance of shear links. To perform validation of the numerical study, the research is followed by experimental work conducted in Structural Mechanic Laboratory Center for Industrial Engineering ITB. The Structures and Mechanics Lab rotary PAU-ITB. The experiments were carried out using three test specimens with model and dimension identical to the model in the numerical study. Experimental testing apparently has shown results of the same behavior as predicted in the numerical study. However, when it is compared to the shape of the hysterical curve, a slight difference is apparent. This is due to the influence of stiffness of bolt joints and the supports which is difficult to model precisely in the numerical studies. 
The Effect of Nitrogen Gas Flushing on Intermediate Products Formation in Acidogenic Stage of Anaerobic Process of Cocoa Sweatings Mindriany Syafila; Marisa Handajani; Adearty Prayascitra
Journal of Engineering and Technological Sciences Vol. 42 No. 2 (2010)
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.2010.42.2.2

Abstract

Cocoa is one of Indonesian-main plantation commodities. During the cocoa seed drying process, there are two types of waste that are cocoa pod and cocoa sweating. Since the organic compounds contained in cocoa sweating is high enough, it is possible to anaerobically treat this wastewater in order to recover either intermediate or end products. Preliminary study showed that the existence of H2 in the reactor would block acetic acid formation. Therefore, the aim of this current experiment was to decrease hydrogen partial pressure by flushing various nitrogen gas flow rate to shift the intermediate products during the cocoa sweating anaerobic treatment. The experiments were carried on a Circulating Bed Reactor (CBR) which contained organic compounds around 100,000 mg/l COD. Then, the reactor was flushed continuously with nitrogen gas as without flushing, 125 ml/min, 500 ml/min and 750 ml/min. The results show there was a possibility that the introduction of nitrogen gas into the reactor could shift the profile of the intermediate product formation. At lower nitrogen gas flow rate more ethanol was formed than acetate formation, although at higher nitrogen gas flow rate the formation of acetate was still low enough. 
Geoelectrical Resistivity and Hydrogeochemical Contrast between the Area that Has BeenApplied with Fertilization for Long Duration and Non-Fertilization Nur Islami
Journal of Engineering and Technological Sciences Vol. 42 No. 2 (2010)
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.2010.42.2.4

Abstract

Integrated geoelectrical resistivity, hydrogeochemical and soil properties analysis methods were used to study the area that has been applied with fertilization for long duration and non-Fertilization in Machang, North Kelantan. The Machang plain is covered with Quaternary fluvial sediments overlying granite bedrock. The drainage system is dendritic with the main river flowing into the South China Sea. In this study, the area was divided into two sites. Site-1 is the non-fertilized site, and Site-2 is the regularly-fertilized site. At shallow depth from the surface to depths of 75 cm a lower average geoelectrical resistivity values were obtained from the regularly fertilized site which has not been fertilized for the last ten months prior to the survey. The average resistivity values were around 0.366 times less in unfertilized sites. Residual nitrate and chloride were still present at the regularly chemically fertilized sites. At sites where no chemical fertilizer was added, the nitrate and chloride concentration were also found. These are due to the faces excretion of from the farm animals. The presence of nitrate and chloride content in pore water reduced the resistivity values. Thus despite low moisture content, the resistivity values to remain low. Normally, resistivity values are inversely proportional to moisture content for area with similar soil condition. 
A Two Control Limits Double Sampling Control Chart by Optimizing Producer and Customer Risks Dradjad Irianto; Ani Juliani
Journal of Engineering and Technological Sciences Vol. 42 No. 2 (2010)
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.2010.42.2.5

Abstract

Standard Shewhart process control chart has been widely used, but it is  not  sensitive  in  detecting  small  shift.  A  number  of  alternatives  have  been proposed to improve the  capability  of control chart. The double sampling (DS) control chart is aimed at improving the capability to detect any small shift out-of control  condition  by  observing  the  second  sample  without  interruption.  The capabilities  of DS control chart were measured as the expected sample size (as a measure  of  inspection  cost)  or  the  control  chart  power  (as  a  measure  for customer  risk).  Optimization  of  these  criteria  is  used  to  determine  the  control limits.  In  this  paper,  we  optimize  both  producer  and  customer  risks  under  a certain expected number of sample sizes as the constraint. Comparing the result to  the  previous  procedure  that  only  optimize  customer  risk,  the  proposed optimization  procedure  gives  the  same  first  control  limit  but  smaller  second control limits with higher value of control chart power.
Effect of Rake Angle on Stress, Strain and Temperature on the Edge of Carbide Cutting Tool in Orthogonal Cutting Using FEM Simulation Hendri Yanda; Jaharah A. Ghani; Che Hassan Che Haron
Journal of Engineering and Technological Sciences Vol. 42 No. 2 (2010)
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.2010.42.2.6

Abstract

Demand for higher productivity and good quality for machining parts has encourage many researchers to study the effects of machining parameters using FEM simulation using either two or three dimensions version. These are due to advantages such as software package and computational times are required. Experimental work is very costly, time consuming and labor intensive. The present work aims to simulate a three-dimensional orthogonal cutting operations using FEM software (deform-3D) to study the effects of rake angle on the cutting force, effective stress, strain and temperature on the edge of carbide cutting tool. There were seven runs of simulations. All simulations were performed for various rake angles of -15 deg, -10 deg, -5 deg, 0 deg, +5 deg, +10 deg, and +15 deg. The cutting speed, feed rate and depth of cut (DOC) were kept constant at 100 m/min, 0.35 mm/rev and 0.3 mm respectively. The work piece used was ductile cast iron FCD500 grade and the cutting tool was DNMA432 series (tungsten, uncoated carbide tool, SCEA = 0; and radius angle 55 deg). The analysis of results show that, the increase in the rake angle from negative to positive angle, causing the decrease in cutting force, effective stress and total Von Misses strain. The minimum of the cutting force, effective stress and total Von Misses strain were obtained at rake angle of +15 deg. Increasing the rake caused higher temperature generated on the edge of carbide cutting tool and resulted in bigger contact area between the clearance face and the workpiece, consequently caused more friction and wear. The biggest deformation was occurred in the primary deformation zone, followed by the secondary deformation zone. The highest stress was also occurred in the primary deformation zone. But the highest temperature on the chip usually occurs in secondary deformation zone, especially in the sliding region, because the heat that was generated in the sticking region increased as the workpiece was adhered by the tool and later it was sheared in high frictional force. 
The Influence of Pt Atomic Ratio in the Activity PtNi/C Nanocatalysts for the PEMFC Nenen Rusnaeni; Widodo Purwanto W.; Mohammad Nasikin; Lilik Hendrajaya
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.2011.43.1.1

Abstract

Pt-Ni/C alloy nanocatalysts synthesized by polyol method with different atomic ratio are investigated to enhance activity of the oxygen reduction reaction (ORR) for fuel cell applications. Prepared catalysts are characterized by various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM-EDX), and cyclic voltammetry (CV). XRD analysis shows that all prepared catalysts with different atomic ratio exhibit face centered cubic and have smaller lattice parameters than pure Pt catalyst. The mean particle size of the catalysts are between 4.3 to 6.3 nm. Cyclic voltammograms with scan rate 5 mV s-1 at 25oC obtain range the electrochemical active surface (EAS) between 40 to 164 cm2/mgPt, mass activity (MA) and specific activity (SA) of nanocatalysts PtNi/C in the potential range 900 mV versus RHE between 3.61 to 8.42 mA/mgPt, and 0.05 to 0.09.
The All-DQ-Domain EMTP Gibson H.M. Sianipar
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.2011.43.1.2

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. 
An Experimental Investigation of Passive Variable-Pitch Vertical-Axis Ocean Current Turbine Ridho Hantoro; I.K.A.P Utama; Erwandi Erwandi; Aries Sulisetyono
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.2011.43.1.3

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. 
Statistical Evaluation of Non-Agglomerating Coating for Granulated Natural Asphalt Tjokorde Walmiki Samadhi; I Dewa Gede Arsa Putrawan; Bambang Eko Prabowo; Alinda Dwitawidi
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.2011.43.1.4

Abstract

Agglomeration of granulated Buton natural asphalt during storage is of major concern in its large-scale commercial application. This work develops a simple test method to evaluate the performance of agglomeration-resistant coating for granulated Buton asphalt, consisting of water-based polymeric primary coating and mineral-based secondary coating. The method uses a static load cell to measure the agglomerated granule count fraction under simulated storage conditions. A 24-1 fractional factorial experiment with two replications is employed to evaluate the effect of coating drying temperature, drying time, asphalt to secondary coating mass ratio, and secondary coating type on the agglomerated count fraction at ambient temperature and 60 oC. The test is able to measure a statistically significant increase in agglomeration resistance when the coating is applied, with an agglomerated fraction of 17.5% at 60 oC. The test identifies asphalt to secondary coating weight ratio as a significant factor, with an ANOVA p-value much lower than other effects. A decrease in this mass ratio from 5:1 to 5:2 increases the agglomeration, which is hypothesized to be attributed to the hydrated cementitious phase between granular external surfaces. More work is needed to identify the acceptable fraction of agglomerated granules.

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