Journal of Engineering and Technological Sciences
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)
Articles
1,267 Documents
Autonomous Coastal Land Cover Assessment Using Polarimetric Decomposition of SAR Data
Trisasongko, Bambang H.
Journal of Engineering and Technological Sciences Vol 43, No 2 (2011)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2011.43.2.2
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.
The Maximum Amplitude Weighted Integrated Energy Spectra: A New Gauge in Seismic Thin-Bed Interpretation
Purnomo, Eko;
Ghosh, Deva Prasad
Journal of Engineering and Technological Sciences Vol 47, No 1 (2015)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2015.47.1.2
Some combinations of seismic attributes are superior in detecting thinbed thickness from 3D seismic data. However, their physical unit or meaning can be difficult to determine. Such attributes are considered as relative values. This paper introduces a newly developed relative-value attribute, which was identified to be more sensitive in detecting seismic thin-bed structures. The new attribute was developed based on seismic frequency shifting and amplitude decrease phenomena that occur when the seismic wave responds to a thinning bed structure. The new attribute is constructed by multiplying the integrated energy spectra with the relative maximum amplitude. Through a wedge model seismic test it was shown that the new relative-value attribute consistently gave more proportional and linear responses to the thin-bed thickness. The new attribute was examined in delineating a channel structure on the basis of public 3D seismic data from Stratton Field, Texas USA and the Group F Reservoir in the Malay Basin, Malaysia. The new attribute delineated the meandering channels featured in those two fields very well.
Confinement of Reinforced-Concrete Columns with NonCode Compliant Confining Reinforcement plus Supplemental Pen-Binder
Kristianto, Anang;
Imran, Iswandi;
Suarjana, Made;
Pane, Ivindra
Journal of Engineering and Technological Sciences Vol 44, No 3 (2012)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2012.44.3.2
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.Â
Quantitative Analysis of Liquid by Quick Freezing Into Ice Using Nd-YAG Laser-Induced Atmospheric Plasma
Yulianto Ichwan, Mohamad Infrawan;
Suyanto, Hery;
Suliyanti, Maria Margaretha;
Hedwig, Rinda;
Pardede, Marincan;
Kagawa, Kiichiro;
Lie, Tjung Jie;
Kurniawan, Koo Hendrik
Journal of Engineering and Technological Sciences Vol 37, No 1 (2005)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2005.37.1.4
A new approach of quantitative analysis of liquid sample using laser ablation technique was developed. The liquid was immediately freezed using the mixture of dry ice and alcohol in weight ratio of 95% : 5%. As a result, an increase of the repulsion force from the sample surface will enable the generation of the laser-induced shock wave plasma which was difficult to carry out on liquid surface. The ice sample was then irradiated using Nd-YAG laser operated in its fundamental wavelength. In order to increase the signal to background ratio and to obtain a sharp atomic line spectra, helium gas was used instead of air. Dynamic characterization of the spatially integrated time profile of the Cu I 521.8 nm, Cu I 510.5 nm and Hα lines shows a shock excitation stage and cooling stage which is corresponded to our shock wave model even when the plasma was generated under atmospheric gas pressure. Further study of the time profile averaged temperature of the atmospheric plasma also shows an increase of temperature during the shock excitation stage followed by diminution of temperature during the cooling stage. An application of this technique was then applied to quantitative analysis of several liquid samples. A linear calibration curve which intercept at 0 point was obtained for all of the elements investigated in this study such as sodium, potassium, lithium, copper, silver, lead and aluminum. A detection limit of around 1 ppm was found for the above element. This new technique will contribute to a great extent of laser atomic emission spectrochemical analysis for liquid samples.
Experimental Study of an Aluminum-Polysilicon Thermopile for Implementation of Airflow Sensor on Silicon Chip
Subandi, Ayub;
Idris, Irman;
Ahmad, Adang Suwandi
Journal of Engineering and Technological Sciences Vol 39, No 2 (2007)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2007.39.2.2
A multi-directional airflow sensor has been realized. The essential part of the considered sensor is a thermopile configuration, which enables the measurement of flow speed and flow direction. The thermopile is a series arrangement of eight thermocouples. A thermocouple converts a difference in temperature into an electrical signal, by means of the Seebeck effect . The thermocouples are made of aluminum-N-type polysilicon junctions. The incoming flow is heated and the degree of heat transfer by convection to the flow, depends on the speed of the flow; the faster the flow the smaller the heat transfer, which leads to a smaller (Seebeck) output voltage of the thermopiles. After signal conditioning - i.e., filtering and amplification by means of an amplification system - the electrical output signals of the thermopiles are further signal-processed by applying analog-to-digital signal conversion, so that finally the flow speed and the flow direction can be properly displayed on a computer screen. The measured values of the Seebeck coefficient or thermopower (S) were in the range of: 0.43 to 0.68 mV/K which are in good agreement with the values found in the literature: 0.5 to 0.7 mV/K. Moreover, it was found that the flow speed Uï¥ is proportional to the reciprocal value of the square of the output voltage of the outgoing thermopile.
Characterization of Chemical and Physical Properties of Hydroxypropylated and Cross-linked Arrowroot (Marantha arundinacea) Starch
Maulani, Rijanti Rahaju;
Fardiaz, Dedi;
Kusnandar, Feri;
Sunarti, Titi Candra
Journal of Engineering and Technological Sciences Vol 45, No 3 (2013)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2013.45.3.1
The modern food industry and a variety of food products require tolerant starch as raw material for processing in a broad range of techniques, from preparation to storage and distribution. Dual modification of arrowroot starch using hydroxypropylation and cross-linking was carried out to overcome the lack of native arrowroot starch in food processing application. The modifications applied were: combined propylene oxide (8%, 10%, and 12%); sodium tri meta phosphate/STMP (1%, 2%, and 3%); and sodium tri poly phosphate/STPP (4%, 5%, and 6%). These modifications significantly affected the composition of the amylose and amylopectin and the amount of phosphorus in the granules. Higher amounts of phosphate salt gave a higher phosphorus content, which increased the degree of substitution (DS) and the degree of cross-link. Arrowroot starch that was modified using a concentration of 8-10% propylene oxide and 1-2% STMP : 3-5% STPP produced a starch with < 0.4% phosphorus content. A higher concentration of propylene oxide provided a higher degree of hydroxypropyl. The changed physical properties of the modified granular arrowroot starch were examined through SEM testing, and its changed crystalline patterns through X-ray diffraction measurements. Especially, provision of a high concentration of propylene oxide (12%) combined with 3% STMP : 6% STPP affected the granular morphology and the crystallinity.
Geoelectrical Resistivity and Hydrogeochemical Contrast between the Area that Has BeenApplied with Fertilization for Long Duration and Non-Fertilization
Islami, Nur
Journal of Engineering and Technological Sciences Vol 42, No 2 (2010)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2010.42.2.4
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.Â
Core Spreading Vortex Method for Simulating 3D Flows Around Bluff Bodies
Zuhal, Lavi Rizki;
Dung, Duong V.;
Sepnov, Alex J.;
Muhammad, Hari
Journal of Engineering and Technological Sciences Vol 46, No 4 (2014)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2014.46.4.7
This paper presents the development of core spreading vortex element method, which is a mesh-free method, for simulating 3D viscous flow over bluff bodies. The developed method simulates external flow around complex geometry by tracking local velocities and vorticities of particles introduced within the fluid domain. The viscous effect is modeled using core spreading method coupled with the splitting spatial adaption scheme, and a smoothing interpolation scheme for overlapping issue and population control, respectively. The particleâs velocity is calculated using Biot-Savart formulation. To accelerate computation, Fast Multipole Method (FMM) is employed. The solver is validated, for both unbounded and bounded flows at low Reynolds numbers, using a number of benchmark problems. For unbounded case, simulation of the collision of two vortex rings was performed. To test the performance of the method in simulating bounded flow problem, simulation of flow around a sphere was carried out. The results are found to be in good agreement with those reported in literatures and also simulations using other diffusion model.
Simple Fabrication of Carbon Nanotubes from Ethanol using an Ultrasonic Spray Pyrolysis
Abdullah, Mikrajuddin;
Iskandar, Ferry;
Okuyama, Kikuo
Journal of Engineering and Technological Sciences Vol 36, No 2 (2004)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/10.5614/itbj.eng.sci.2004.36.2.3
Carbon nanotubes of diameter (20â100 nm) are synthesized by pyrolyzing a sprayed solution of Fe(C5H5)2 and C2H5OH in an Ar atmosphere at relatively low temperatures (around 800 oC). The tubular structures consist of highly crystalline nested graphene cylinders (<200 concentric tubes). Tube diameter can be controlled by varying the furnace temperature, carrier gas flow rate and the Fe:C ratio within the precursor solution. This low cost route for the synthesis of carbon nanotubes is advantageous due the low pyrolytic temperature, safety, processable in atmospheric pressure, and scalable.
MIMO Frequency Sampling Filters for Modelling of MIMO System Applications
Aziz, Muhammad Hilmi R. A.;
Mohd-Mokhtar, Rosmiwati
Journal of Engineering and Technological Sciences Vol 45, No 1 (2013)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2013.45.1.6
In the modelling of a system based on a system identification approach, data acquisition is the first procedure that must be carried out. The data acquisition process from a real system typically yields large amounts of data. This may lead to unacceptable computational time during the identification process. Raw data may also suffer severe noise disturbance, especially in the high frequency region. In addition, bias estimation will occur if one only considers direct identification from a closed-loop system. To overcome this problem, in this paper a multivariable frequency sampling filter approach is introduced. Multi-input-multi-output (MIMO) raw data are analyzed in order to obtain only relevant and meaningful parameters that describe the empirical model of the analyzed data. By performing this procedure, compressed, cleaned and unbiased data are produced. The efficacy of the MIMO frequency sampling filters was demonstrated by compressing two sets of data: pH neutralization process data and steam generator plant data. The results show that the amount of raw data was successfully compressed and that the output was ready for identification purposes with less computational time, i.e. they could be further used to develop a model of the system, to conduct time and frequency response analysis, and also for developing a new control system design.