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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)
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Articles 10 Documents
 1 
Search results for , issue "Vol. 50 No. 2 (2018)" : 10 Documents clear
Analysis of Stiffening Methods and Effects on Irregular Single-layer Lattice Shell Structures Jianshe Xu
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.1

Abstract

Local stiffening is often a good solution to mechanical property problems of irregular single-layer lattice shell structures. The effects of three local stiffening methods, namely section enlargement stiffening, planar truss stiffening, and space truss stiffening, on their structural stiffness, strength, and overall stability were analyzed in this study. A practical engineering example showed that these three stiffening methods could effectively reduce the deformation of the lattice shell under vertical and lateral loads, reduce the comprehensive stress ratio, and increase the buckling eigenvalue and ultimate bearing capacity factor. The local space truss stiffening method had the best comprehensive effect. The same stiffening methods were applied to a regular lattice shell and the analysis showed that the stiffening effect on a regular shell is quite different from that on an irregular lattice shell. The three stiffening methods could not reduce its deformation under vertical loading but could reinforce the strength and overall stability of the structure effectively. Proper suggestions are proposed according to the preceding analysis in case a single-layer lattice shell structure cannot meet the demands of the design code.
Effect of Polystyrene Latex Addition on Size and Pore Volume of Porous Calcium Oxide Particles Prepared by Spray-Pyrolysis Method and Its Ability for SO2 Retention Ricky Dwi Septianto; Ferry Iskandar; Mikrajuddin Abdullah; Khairurrijal Khairurrijal; Lee Myong Hwa
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.6

Abstract

In this study, the effects of polystyrene (PS) latex addition on the particle morphology and the pore content of calcium oxide (CaO) were investigated. The CaO particles were prepared using an ultrasonic nebulizer-assisted spray-pyrolysis method with variation of the PS/Ca(NO3)2·4H2O mass ratio in the precursor. Good crystallinity of CaO was obtained at 825°C of synthesis temperature under 2 l/min of nitrogen gas flow, which was confirmed by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). According to scanning electron microscope (SEM) characterization, the CaO particles synthesized with 0 and 25 wt% PS addition had an almost spherical shape with an average size of 1.58 and 1.48 µm, respectively. In addition, macropores were formed in the CaO particles prepared with 25 wt% PS addition that had an average pore diameter of 583.26 nm. Meanwhile, the CaO particles prepared with 75 wt% PS addition had a random shape and an average size of 1.41 µm. The mesopore content was investigated by Barret-Joyner-Halenda (BJH) analysis, which showed improvement of the pore size from 3.45 nm to 5.42 nm for 0 and 25 wt% PS addition, respectively, which is proportional to the pore volume, pore surface area, and the capacity of SO2 retention.
Development of Braking Force Distribution Strategy for Dual-Motor-Drive Electric Vehicle Binbin Sun; Pengwei Wang; Song Gao; Jie Yu; Zhangu Wang
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.3

Abstract

In the development of the optimal braking force distribution strategy for a dual-motor-drive electric vehicle (DMDEV) with a series cooperative braking system, three key factors were taken into consideration, i.e. the regenerative force distribution coefficient between the front and the rear motor (β), the energy recovery coefficient at the wheels (α3), and the front-and-rear-axle braking force distribution coefficient (λ). First, the overall power loss model of the two surface-mounted permanent magnetic synchronous motors (SMPMSMs) was created based on the d-q axis equivalent circuit model. The optimal relationship of β and the overall efficiency of the dual-motor system were confirmed, where the latter was quite different from that obtained from the traditional look-up table method for the motors' efficiency. Then, four dimensionless evaluation coefficients were used to evaluate braking stability, regenerative energy transfer efficiency, and energy recovery at the wheels. Finally, based on several typical braking operations, the comprehensive effects of the four coefficients on braking stability and energy recovery were revealed. An optimal braking force distribution strategy balancing braking stability and energy recovery is suggested for a DMDEV with a series cooperative braking system.
Seismic Behavior of Tunnel Form Building under Lateral Cyclic Loading Nor Hayati Abdul Hamid; Shamilah Anuar; Haryati Awang; Mahmud Kori Effendi
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.5

Abstract

A three-story single-unit tunnel form building (TFB) was designed using a non-seismic code of practice (BS 8110). Two one-third scale test models were constructed and tested under in-plane lateral cyclic loading and out-of-plane lateral cyclic loading, respectively. The specimens were tested at ±0.01%, ±0.1%, ±0.25%, ±0.5%, ±0.75%, ±1.0%, ±1.25%, ±1.5%, ±1.75% ±1.8, ±1.9% and ±2% drifts, after which severe cracks were observed on the wall-slab joints and wall panels. Subsequently, the damaged specimens were repaired and retrofitted by wrapping carbon fiber reinforced polymer (CFRP) around the damaged walls and affixing steel plates and steel angles at the wall-slab joints using several different repair and retrofitting schemes. The repaired specimens were retested using the same drifts. The comparison of the seismic behavior between unrepaired and repaired specimens was made based on visual observation of damage, hysteresis loops, lateral strength capacity, stiffness, ductility, and equivalent viscous damping. The experimental results showed that the repaired specimens were improved in terms of damage, lateral strength capacity, stiffness, ductility, and equivalent viscous damping. It is recommended to strengthen and rehabilitate tunnel form buildings after an earthquake using CFRP, additional shear walls, steel plates and steel angles.
Study on the Performance of Ball Mill with Liner Structure based on DEM Zhanfu Li; Yaokun Wang; Kunyuan Li; Wenyu Lin; Xin Tong
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.2

Abstract

This study used the discrete element method (DEM), which is effective and popular for solving the problem of granular systems simulating the motion of particles in a ball mill in different structural forms and at different rotational speeds. Firstly, simulations of five kinds of lifters (triangular, trapezoidal, rectangular, ladder and hemispherical) were set up. The results were as follows: when the rectangular lifter was selected as mill liner, the ball mill efficiency was significantly high. The breaking performance of the hemispherical lifter and the ladder lifter was poor, because the main pattern of motion was grinding rather than impact breakage. Secondly, the effects of the height"“width ratio of the rectangular lifter, the height of the lifter and the number of lifters on the working efficiency of the ball mill were studied. It was found that a number of rectangular lifters of 12 and a height-width ratio of 3:1 produced the best results. The best height of the rectangular lifter was about 13 mm. Lastly, displacement, stress and deformation were analyzed using DEM coupled with a finite element method (FEM). The purpose was to design the geometrical lifter structure and to improve the performance of the ball mill.
Fuzzy-Based Prediction of Spatio-Temporal Distribution of Wet Muck in Block Cave Mine of PT Freeport Indonesia Lilik Eko Widodo; Eman Widijanto; Iftikhor Faadhilah; Wahyu Sunyoto
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.9

Abstract

Mud rushes, or wet muck spills, are hydro-geotechnical challenges in block cave mines where wet muck spills out of drawpoints formed by the accumulation of fine materials and water in drawbells. The purpose of this paper is to share the results of the developement of an improved predictive tool that can be used to manage wet muck spills. The tool was developed based on the hybrid modeling of wet muck distribution using fuzzy logic and fuzzy number operations. The fuzzy logic operations were applied to model the spatial distribution of wet muck classes, providing the spatial model of drawpoint status based on five contributing factors, i.e. the height of draw, the water content, the grain size of the fine material, rainfall, and no-mucking days. The fuzzy number operations were used in accordance with the mass balance principle to estimate the temporal distribution of wet muck that forms a mud deposit consisting of fine materials and water in a drawbell. The mass balance principle was expressed using the fuzzy ordinary differential equation, including the uncertainty of joining variables. A wet muck spill event at the Deep Ore Zone (DOZ) block cave mine of PT Freeport Indonesia was utilized as a case study as well as to validate the proposed method. The fuzzy-based approach shows promising results in predicting wet muck spill events.
Analysis of Protein Separation Mechanism in Charged Ultrafiltration Membrane Danu Ariono; Putu Teta P. Aryanti; Anita Kusuma Wardani; I Gede Wenten
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.4

Abstract

The separation mechanism of proteins on a charged ultrafiltration membrane was analyzed using the extended Nernst"“Planck (N-P) model. The model was solved numerically based on experimental data during ultrafiltration of bovine serum albumin/BSA and hemoglobin at various pH (between 5 and 8) to obtain the flux parameter (Jv). The flux parameter was used to determine the effective charge of the membrane (f) and the actual membrane porosity (Ak). These two parameters were then used to predict the transport mechanism of proteins through the charged membrane. Higher flux was obtained during the ultrafiltration of BSA compared to hemoglobin. The most effective separation of mixed proteins occurred at pH 5 (aalbumin= 5). In addition, the mobility of a single protein was lower than when it was mixed with other proteins that had different charges. The effective charges of the membranes were varied between 0.99996 to 1.0000, which means that the fixed charge on the membrane structure was higher than the concentration of proteins, thus the effective charge of the membrane was not influenced by the presence of protein charge at various pH. On the contrary, the value of Ak was influenced by the type and charge of the proteins. A decrease of negative charge along with an increase of solution pH increased the porosity of the membrane, thus reducing the rejection of proteins.
Production of Biopolymer Polyhydroxyalkanoates (PHA) by Extreme Halophilic Marine Archaea Haloferax mediterranei in Medium with Varying Phosphorus Concentration Susiana Melanie; James B. Winterburn; Hary Devianto
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2017.50.2.7

Abstract

The development of plastics production from biodegradable resources such as polyhydroxyalkanoates (PHAs) is important due to the increasing demand for plastics. PHAs occur as intracellular solid materials produced by microorganisms as a result of an excess of carbon source and a limitation of nutrients. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) or PHBV, as one of the PHAs, is a combination of two homopolymers, namely poly-3-hydroxybutyrates (PHB) and poly-3-hydroxyvalerates (PHV). This study aimed to investigate the effect of the phosphorus concentration on the production of PHAs by Haloferax mediterranei. It is possible that phosphorus deficiency may affect the length of the HV chains in the copolymer structure and thus influence the copolymer properties. The experiment was done in triplicate at laboratory scale by culturing H. mediterranei in medium with phosphorus limitation using various phosphorus concentrations. During cultivation, the optical density, phosphorus concentration, pH, and dry cell weight were observed. The PHBV product was collected and analyzed using gas chromatography. The result shows that medium with a phosphorus concentration of 0.5 g/L produced higher PHAs than the other phosphorus concentrations. The accumulated PHA was 0.95 g/L with 15.6% of dry biomass and yield YPHA/S of 0.1 g/g.
Guidelines for Process Safety Hazard Assessment Based on Process Information Muhammad Firdaus Husin; Mimi H. Hassim; Denny K. S. Ng; Anwar Johari; Mohd. Johari Kamaruddin; Norzita Ngadi
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2018.50.2.8

Abstract

In any new chemical process development and design, process safety is a critical aspect to be considered besides economic and technical feasibility of the manufacture of the product. A lack of proper hazard assessment during the design phase may later result in accidents with disastrous consequences to workers, the public as well as the environment. Many methods have been introduced to qualitatively and quantitatively assess the safety level of processes. Despite the availability of a large amount of methods, a systematic framework that details guidelines for hazard identification, risk assessment, safety measure design, and safe critical decision-making is still missing. To address this issue, the main objective of this study was to propose a systematic framework that outlines comprehensive guidelines for assessing the safety performance of processes based on information from the piping and instrumentation diagram (P&ID). Apart from proposing the framework, appropriate strategies for minimizing safety hazards and risks are also recommended. In addition, the user is assisted in selecting the most appropriate assessment method according to his or her needs and the scope and constraints of the assessment. A case study is presented to illustrate the application of the proposed framework.
Cover JETS Vol. 50 No. 2, 2018 Journal of Engineering and Technological Sciences
Journal of Engineering and Technological Sciences Vol. 50 No. 2 (2018)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

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