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
Dynamic Behavior of Reverse Flow Reactor for Lean Methane Combustion
Budhi, Yogi W.;
Effendy, M.;
Bindar, Yazid;
Subagjo, S.
Journal of Engineering and Technological Sciences Vol 46, No 3 (2014)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2014.46.3.5
The stability of reactor operation for catalytic oxidation of lean CH4 has been investigated through modeling and simulation, particularly the influence of switching time and heat extraction on reverse flow reactor (RFR) performance. A mathematical model of the RFR was developed, based on one-dimensional pseudo-homogeneous model for mass and heat balances, incorporating heat loss through the reactor wall. The configuration of the RFR consisted of inert-catalyst-inert, with or without heat extraction that makes it possible to store the energy released by the exothermic reaction of CH4 oxidation. The objective of this study was to investigate the dynamic behavior of the RFR for lean methane oxidation and to find the optimum condition by exploring a stability analysis of the simple reactor. The optimum criteria were defined in terms of CH4 conversion, CH4 slip, and heat accumulation in the RFR. At a switching time of 100 s, the CH4 conversion reached the maximum value, while the CH4 slip attained its minimum value. The RFR could operate autothermally with positive heat accumulation, i.e. 0.02 J/s. The stability of the RFR in terms of heat accumulation was achieved at a switching time of 100 s.
Structure Refinement of Five Layers Aurivillius Compound: Ba4Bi2Nb2Ti3O18
Ismu, Ismunandar;
Mikrianto, Edi
Journal of Engineering and Technological Sciences Vol 36, No 1 (2004)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2004.36.1.4
The room temperature structures of the five layers Aurivillius phase Ba4Bi2Nb2Ti3O18 has been refined from X-ray powder diffraction data using the Rietveld method. The structures consist of [Bi2O2]2+ layers interleaved with perovskite-like [Ba4Nb2Ti3O16]2- blocks. The oxides was found to be orthorhombic (SG B2cb); a = 5.5017(8), b = 5.5031(8), c = 50.363(3) Ã
, Rp = 25.53 Rwp = 35.54 Rexp = 29.30 RBragg = 9.92. The structural features of the compound is found similar to that of other layered Aurivillius compounds. Using the available structural data the ferroelectric properties could be explained and strategies to find good ferroelectric materials could be inferred.
Effects of Fracture Parameters in an Anisotropy Model on P-Wave Azimuthal Amplitude Responses
Fatkhan, Fatkhan
Journal of Engineering and Technological Sciences Vol 38, No 2 (2006)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2006.38.2.6
The study showed that the presence of vertically aligned fractures in reservoir rock could possibly be inferred through analysis of P-wave reflectivity variations with azimuth. The azimuthal amplitude responses measured at an interface separating overburden anisotropy and fractured rock rely on several parameters that can be decomposed into the background rock and the fracture contributions.The effect of fracture porosity on P-wave azimuthal amplitude response is small for moderate incidence angles. For fluid filled fractures P-wave anisotropy is mildly affected. For dry fractures the difference in P-wave anisotropy between low and high fracture porosities is high. This suggests that an assumption of overburden isotropy may result in a large error in predicting the fluid type and saturation.
Vortex-induced Vibration of a Flexible Free-hanging Circular Cantilever
Prastianto, R. W.;
Otsuka, K.;
Ikeda, Y.
Journal of Engineering and Technological Sciences Vol 41, No 2 (2009)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2009.41.2.2
The behavior of a free-hanging riser of floating offshore structures would be different from a typical at-sea-floor-terminated riser type of oil or gas platforms. For the design purpose, the present study was intended to incorporate some important factors of the riser conditions (i.e. bidirectional vibration, freeend condition, and spanwise variation of response amplitude) for investigating its dynamics characteristics. An experimental investigation on time-dependent motion of a flexible free-hanging circular cantilever subjected to uniform crossflows has been carried out. The free-end condition cantilever has a 34.4 aspect ratio and a low mass ratio of about 1.24. The cylinder freely oscillates in both inline and transverse to the flow. Reynolds number varied from 10,800 to 37,800. The âjump phenomenonâ was found in the inline motion of the cylinder that agrees well with an existing comparable work. At high flow velocities, the 3rd higher harmonic frequencies of the cylinder transverse response became predominant that produce quite different motion characteristics compared to the other existing comparable works with 2-dimensional bottom-end condition. Generally, the results suggested that the flexible free-hanging cantilever generate different vortex wake mode than either, a uniform (a short-rigid flexiblymounted cylinder) or a linear amplitude variation along the span case (a pivoted cylinder)
Parameter Selection of Oscillator Resonant Circuit Based on Stochastic Differential Equation
Feng, Yan Gang;
Xian He, Huang;
Jing, Xu Ning
Journal of Engineering and Technological Sciences Vol 46, No 2 (2014)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2014.46.2.4
Because the choice of oscillator resonant circuit parameters depends mostly on experience, we propose nonlinear differential equations to describe an oscillator based on an equivalent circuit of the oscillator and then to describe the internal electrical noise of the oscillator by introducing a stochastic term that establishes a nonlinear stochastic differential equation to analyse the oscillatorâs behavior. For optimization of the oscillator resonant circuit parameters, first, we used Advanced Design System (simulation software of the Agilent company) to verify the conclusion, and then, using a 10MHz Pierce crystal oscillator, provided experimental evidence.
Effect of Tensile Reinforcement Ratio on the Effective Moment of Inertia of Reinforced Lightweight Concrete Beams for Short Term Deflection Calculation
Akmaluddin, Akmaluddin
Journal of Engineering and Technological Sciences Vol 43, No 3 (2011)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2011.43.3.4
This paper presents an improvement model of the effective moment of inertia to predict the short term deflection of reinforced lightweight concrete beam. The models were developed using 9 beams of reinforced pumicelightweight concrete tested under two symmetrical-point loads. The presence of steel reinforcement in the beam was taken into consideration in the developed model. The models were verified by test carried out on other 9 beams. Those beams subjected to various-point loads and compressive strength. The results of investigation revealed that crack moment of inertia increased with the increased tensile reinforcement ratio. Thus, the reinforcement ratio significantly affects the value of effective moment of inertia of reinforced lightweight concrete beam. All the beam test results produced considerable deflection in comparison to that obtained using current Codes either ACI or SNI. The proposed model demonstrated a good agreement to the experimental results and in some cases have similar trend to that of the ACI or SNI prediction.
Surface Vibration Reconstruction using Inverse Numerical Acoustics
Martinus, F.;
Herrin, D. W.;
Seybert, A. F.
Journal of Engineering and Technological Sciences Vol 35, No 1 (2003)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2003.35.1.5
This paper explores the use of inverse numerical acoustics to reconstruct the surface vibration of a noise source. Inverse numerical acoustics is mainly used for source identification. This approach uses the measured sound pressure at a set of field points and the Helmholtz integral equation to reconstruct the normal surface velocity. The number of sound pressure measurements is considerably less than the number of surface vibration nodes. An overview of inverse numerical acoustics is presented and compared with other holography techniques such as nearfield acoustical holography and the Helmholtz equation least squares method. In order to obtain an acceptable reproduction of the surface vibration, several critical factors such as the field point selection and the effect of experimental errors have to be handled properly. Other practical considerations such as the use of few measured velocities and regularization techniques will also be presented. Examples will include a diesel engine, a transmission housing and an engine cover.
Overall Buckling and Wrinkling of Debonded Sandwich Beams: Finite Element and Experimental Results
Hadi, Bambang K.
Journal of Engineering and Technological Sciences Vol 38, No 1 (2006)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2006.38.1.4
Overall buckling and wrinkling of debonded sandwich beams under compressive loads were analyzed by both finite element and experimental methods. In the finite element method, a quarter and a half models of the specimens were analyzed. It shows that a quarter model is not adequate to analyze buckling of debonded sandwich beams, since it will disregard overall buckling mode that may occur in sandwich beams having compressive loads. At least a half model should be used to analyze buckling of sandwich beams. A finite element program UNA was used extensively to analyze the buckling loads. Experimental buckling of sandwich beams was carried out using a compression testing machine. Two LVDTs were used to measure deflections of the specimen during experimental loading. The loads were measured using load cells available in the machine. Specimens having core thickness of 45 and 75 mm were tested to represent overall and wrinkling modes respectively. The delamination lengths were 20, 60 and 80 mm, which represent 10, 30 and 40% of the beam length. The results show that the differences between experimental and finite element methods were less than 10%. Both overall buckling and wrinkling modes were shown in these specimens.
Approximation of Hydrogen Induced Delayed Fracture of Overlaid Cladding in Pressure Vessels Steel Structure
Rusli, Ronnie H.;
Fujita, T.
Journal of Engineering and Technological Sciences Vol 40, No 2 (2008)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/itbj.eng.sci.2008.40.2.3
Distribution and electronic states of interstitial hydrogen atoms in the iron lattice are discussed in regard to their influence to the lattice bonding, and theory of hydrogen induced delayed fracture of steel based upon it is proposed. Characteristics of delayed fracture are accordingly well accounted for.
The Behavior of Slab-Column Connections with Modified Shear Reinforcement under Cyclic Load
Gunadi, Riawan;
Budiono, Bambang;
Imran, Iswandi;
Sofwan, Ananta
Journal of Engineering and Technological Sciences Vol 46, No 1 (2014)
Publisher : ITB Journal Publisher, LPPM ITB
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DOI: 10.5614/j.eng.technol.sci.2014.46.1.2
Generally, slab-column frames show lower stiffness, drift capacity, and ductility as compared to beam-column frames. Under combined gravity and lateral cyclic loading, the lower initial stiffness and stiffness degradation lead to poor structural performance. Therefore, in the current codes, slab-column frames are recommended only for Intermediate Moment Frames with dual systems. The objective of this study is to modify slab-column connection details to enhance seismic performance such that the system can also be used with Special Moment Frames. Four specimens of interior slab-column connection models with the same dimensions and flexural reinforcement were tested under gravity and cyclic lateral loads. One specimen, constructed as control specimen, was designed using standard orthogonal stud rails. The other specimens used newly designed stud rails. The experimental results demonstrated that the modified stud rails significantly improved the specimensâ behavior. The experimental results demonstrated that the modified stud rails significantly improve the specimen behavior. The highest ratio of initial stiffness adequacy of specimen with modified stud rail was 131.19% for risk category I/II, while the ratio of the control specimen was 97.94%. The highest relative energy dissipation ratio of specimen with modified stud rail was 33.82%, while the ratio of the control specimen was 25.94%.