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ASEAN Journal on Science and Technology for Development

ajstd
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Published by Universitas Gadjah Mada

ISSN : 22249028 EISSN : 22249028 DOI : -

Core Subject : Science, Education, Engineering,

Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Mathematics

The coverage is focused on, but not limited to, the main areas of activity of ASEAN COST, namely: Biotechnology, Non-Conventional Energy Research, Materials Science and Technology, Marine Sciences, Meteorology and Geophysics, Food Science and Technology, Microelectronics and Information Technology, Space Applications, and Science and Technology Policy, Infrastructure and Resources Development.

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Articles 18 Documents

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Search results for , issue "Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)" : 18 Documents clear

USING CRUDE PALM OIL (CPO) AS DIESEL ENGINE FUEL T.H. Lim; S. Bari; C.W. Yu
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

In this study, heating was used to lower the viscosity of CPO to an acceptable level. 60°C was found to be the optimum heating temperature for CPO to ensure smooth flow in the fuel system, but heating further up to 100°C did not improve the engine performance. A comparison between CPO and diesel in terms of engine performance, combustion characteristics and emission showed that the brake specific fuel consumprion (bsfc) for CPO was 13% higher at 400 kPa brake mean effective pressure (bmep), and the highest bmep achieved was 13.5% lower. However, CPO fuel gave a brake thermal efficiency. Combustion analyses indicated that CPO combustion produced a 7% higher peak pressure, a 3.3-degree earlier ignition and an 11.6-degree longer burning duration, but a 26% lower peak heat release rate. After 500 hours of running CPO, performance and power of the engine dropped even while running with diesel. With a 26% higher bsfc and a 20% lowe maximum bmep. Visual inspection of the dismantled engine parts discovered heavy carbon deposits but normal wear. Overhaul of the engine restored the power and performance.

CATALYTIC ACTIVITY OF ZSM-5 ZEOLITE LOADED WITH TRANSITION METALS FOR THE SELECTIVE CATALYTIC REDUCTION OF NOX I.M. Saaid; A.R. Mohamed; S. Bhatia Bhatia
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Catalytic activity measurement were carried out on catalysts formulated from ZSM-5 zeolite separately loaded with transition metals (Cu, Co, Ni, Fe) for the removal of NOx in simulated diesel exhaust conditions. Various factors were investigated to compare the performance of these catalysts including catalyst preparation method, Si/Al ratio of the parent zeolite support, and durability in the exhaust stream containing water vapor or SO2. In many experimental conditions except in the presence of water vapor or SO2, Cu-ZSM5 remained the most active catalyst with 100% NOX conversion at around 350°C. C0-ZSM5 and Ni-ZSM5 could also achieve complete NOx conversion but at a much higher temperature of around 450°C. Fe-ZSM5 catalyst was the least active catalyst probably due to the formation of iron oxide particle, which accelerated formation of carbon monoxide.

GIANT MAGNETORESISTANCE (GMR): SPINNING FROM RESEARCH TO ADVANCED TECHNOLOGY K.Y. Kok; I.K. Ng
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

In this paper, we aim to examine the research and development of materials demonstrating the giant magnetoresistance (GMR) property, a novel material property that has revolutionalised the advances of magnetic sensor and mass-memory technology today. A comprehensive outline for the fundamental materials aspects as well as the physics of the underlying mechanisms behind the GMR property is given. Recent development of GMR materials in data storage industry and other potential technological applications exploiting the GMR property are also discussed.

USING TWO TIME SCALES OF TURBULENCE FOR BOUNDARY LAYER FLOWS Nawaf H. Saeid
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

A near wall improvement of the k-? model of turbulence is proposed and evaluated. The present model takes into account the asymptotic behavior of turbulent scales near wall region and for free turbulence region. The Kolmogorov turbulent time scale is introduced as a lower limit. The model is used for prediction of turbulent boundary layer flows. Predictions compared with experimental data of several flow cases, with encouraging results.

FACTORS AFFECTING REFRIGERATOR-FREEZERS ENERGY CONSUMPTION R. Saidur Saidur; H.H. Masjuki; T.M.I. Mahlia; A.R. Nasrudin
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Two frost-free household refrigerator-freezers, one with 492 liter capacity and one with 460 liter capacity were tested in the laboratory to determine the sensitivity of several variables those influence consumption refrigerator-freezers energy consumption greatly. The effects of single variables such as room temperature, thermostat setting positions, and door openings on the energy consumption were investigated. Using Response Surface Methodology (RSM), a mathematical model has been developed to investigate the combined effect of room temperature, thermostat setting positions, and door opening on the energy consumption of refrigerator-freezers. From the mathematical model, it has been observed that room-temperature has the highest effect on the energy consumption followed by the thermostat setting position. The door opening has lowest on the energy consumption. More detailed tests were performed under different room temperature, thermostat setting positions, and door opening conditions and presented in this paper.

PERFORMANCE OF MEMBRANES CROSSLINKED WITH GLUTARALDEHYDE IN PERVAPORATION SEPARATION S.H. Tan; A.L. Ahmad; M.G. Mohd. Nawawi; H. Hassan
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Chitosan membranes crosslinked with glutaraldehyde (GA) were prepared through a solution method, where the dry homogeneous chitosan membranes were immersed into the reaction solutions containing 1.25 x 10-3 wt. % of glutaraldehyde (GA). The extent of the crosslinking was controlled by varying the crosslinking time from 1 to 5 minutes. The prepared crosslinked membranes were used for pervaporation dehydration of isopropanol-water mixtures. The influence of feed composition on the separation characteristics has been investigated. The 2-minute-crosslinked-membrane yields the highest water concentrations in the permeate with moderate flux at 50 wt. % of isopropanol in the feed solution. The overall pervaporation results for the homogeneous and crosslinked membranes are compared in term of pervaporation separation index (PSI). The crosslinked membranes showed higher pervaporation separation index (PSI) than that of uncrosslinked membranes especially for isopropanol in feed solution below 78 wt. %.

DESIGN OF ROBUST H? POWER SYSTEM STABILIZER USING NORMALIZED COPRIME FACTORIZATION I. Ngamroo; S. Dechanupaprittha
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

This paper proposes a new design procedure of robust power system stabilizers (PSS) using H? control via normalized coprime factorization (NCF) approach. The design procedure of the proposed PSS is systematically described. Moreover, the selection method of the weighting function in H? control design is explained in a simple manner. The performance and robustness of the proposed PSS are investigated in comparison with the conventional PSS by examining the case of a single machine connected to an infinite bus (SMIB) system. The simulation results are illustrated to ensure the effectiveness of the proposed PSS.

NARROWING THE DIGITAL DIVIDE IN MALAYSIA: ISSUES AND INITIATIVES L.N. Foo; W.K. Lai; C. Elamzazuthi
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Equity of and access to information and communication technologies (ICT) is currently a burning issue in many countries around the world. Malaysia, as a nation with about 22 million inhabitants, has taken some strong strides in recent times to bridge the access and equity gaps through appropriate policies and strategic national programmes. This paper will examine some of the key elements of several of these initiatives to bridge the digital divide in the country, in particular, the Titian Digital programme. We will also be identifying some of the major challenges that this programme hopes to resolve.

ELECTRON MICROSCOPY OF ENTOMOPATHOGENIC FUNGAL INVASION ON THE CABBAGE-HEART CATERPILLAR CROCIDOLOMIA BINOTALIS ZELLER (LEPIDOPTERA: PYRALIDAE) N. Hashim; Y.B. Ibrahim; Y.H. Tan
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

The infection on Crocidolomia binotalis Zeller by the entomopathogenic fungi Paecilomyces fumosoroseus (Wise) Brown and Smith, Beauveria bassiana (Bals.) Vuill, and Metarhizium anisopliae var. majus (Metsch.) Sorokin was studied histopathologically using electron microscopy. Conidia which landed on the cuticle germinated within four to six hours. In the case of B. basiana, shortly after landing, an appresorium was formed that attached itself fast onto the cuticle at the point of fungal entry. The infected larva then entered the moribund state 12 to 24 hours after inoculation. Death of the larva followed 24 to 48 hours later. By then the body cavity as well as the trachea were clogged with mycelia, and compacted masses conidiophores producing white conidia were found all over the larval cadaver one to two days later. P. fumosoroseus sporulated more abundantly on the surface of the cadaver compared to B. bassiana or M. anisopliae.

Fusion Decision for a Bimodal Biometric Verification System Using Support Vector Machine and its Variations A Teoh Samad; A. Hussain
ASEAN Journal on Science and Technology for Development Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

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