Garuda - Garba Rujukan Digital

All

ASEAN Journal on Science and Technology for Development

ajstd
Website

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.

Arjuna Subject : -

Articles 477 Documents

26 27 28 29 30

Effects of pressure on thermal contact resistance for rough mating surfaces M. Z. Abdullah,; Y. C. Yau,; Z. A. Zainal Alauddin, and; K. N. Seetharamu
ASEAN Journal on Science and Technology for Development Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Thermal contact resistance has been studied experimentally to investigate the effect of pressure between two aluminium or two brass rough surfaces at three different heat flux levels. Three different rough surfaces are considered in the range of 2.63 to 40.69?m. It is demonstrated that the thermal contact resistance reduces significantly with pressure for both materials, the harder material gives higher thermal contact resistance as expected

Forecasting water demand using back propagation networks in the operation of reservoirs in the citarum cascade, west java, indonesia Mulya R. Mashudi
ASEAN Journal on Science and Technology for Development Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

This study investigates the use of Neural Networks (NN) as a potential means of more accurately forecasting water demand in the Citarum River basin cascade. Neural Networks have the ability to recognise nonlinear patterns when sufficiently trained with historical data. The study constructs a NN model of the cascade, based on Back Propagation Networks (BPN). Data representing physical characteristics and meteorological conditions in the Citarum River basin from 1989 through 1995 were used to train the BPN. Nonlinear activation functions (sigmoid, tangent, and gaussian functions) and hidden layers in the BPN were chosen for the study.

Membrane cleaning using electric pulse in dead end ultrafiltration of proteinaceous solution A.L. Ahmad'; and I.A. Azid
ASEAN Journal on Science and Technology for Development Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Dead end ultrafiltration of Bovine Serum Albumine (BSA) using a polymeric membrane has been studied. Membrane fouling for such fine biological product due to the formation of filter cake and adsorption of the proteinaceous solution is the major bottleneck for such separation process. The application of electric pulses has shown an effective means in cleaning the membrane and reducing the fouling rate for dead-end ultrafiltration of BSA. The flux is significantly increased by both electrophoretic motion of solutes away from the membrane surface and electro-osmosis occurring in the filter cake. An automated experimental rig equipped with data acquisition system has been developed to test the effectiveness and performance of such membrane cleaning. The improvement of flux becomes more pronounced with increasing electric field strength. The effects of other processing variables such as pulse interval, pulse duration, ionic strength of the electrolyte, pH of the solution and solution concentration were studied on this membrane cleaning technique. Data are analysed for its average flux, average cake concentration, average percentage of cake and water recovery for every cleaning condition. It is found out that the chemical and physical properties of the solution (pH and ionic strength of the electrolyte) have a great effect on this membrane cleaning method. Protein solution at pH 8 and 0.0 lM ionic strength of the electrolyte gave the best membrane cleaning performance. Shorter pulse interval and with relatively 10 seconds pulse duration are the optimum conditions on application of pulse to remove the filter cake from the membrane.

Optical ph sensing material prepared from doped sol-gel film for use in acid-base titration Musa Ahmad; T.W. Tan
ASEAN Journal on Science and Technology for Development Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

An optical pH sensing material has been prepared in this study by using sol-gel technique. Bromothymol blue, bromophenol blue and thymol blue were chosen in this study as acidbase indicators for strong acid-strong base, strong acid-weak base and weak acid-strong base titration, respectively. The results show that these indicators could be successfully entrapped inside the sol-gel film and still maintain its chemical behaviour as in solution. The entrapped acid-base indicators respond well to any pH changes and could be used to determine the end-point of the acid-base titration.

The mechanical properties of fly ash concrete prepared and cured at high temperatures D.R. Munaf; M.S. Besari; M.M. IqbaP; and I. Kadir
ASEAN Journal on Science and Technology for Development Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Results of an experimental investigation on the effect of fly ash content, water cement (w/c) ratio of concrete prepared and cured at temperatures of ambience, 40°C and 60°C are presented in this paper. The mechanical properties investigated here include its workability, its behaviour under compression and splitting tension. Microscopic investigations were also carried out using SEM micrographic images to gain understanding of concrete at its microstructural level.The results indicate that high temperature increases early compressive strengths of concrete, but has decreasing effects on the strengths at later ages. The use of fly ash in concretes cast and cured at elevated temperatures improves the physical and mechanical properties of fresh as well as those of hardened concrete.Various mathematical models describing the properties of such concretes are considered at the end of this paper. The strength properties of high temperature fly ash concrete were best represented by a simple exponential function of time, while its stress-strain relationship could be best described by an exponential function of strain of a more complicated form.

Processing of Cu-Cr alloy for combined high strength and high conductivity Olofinjana and, A.O; Tan, A. and K. S.
ASEAN Journal on Science and Technology for Development Vol. 2 No. 1 (1985): Vol. 2 No. 1 (1985)
Publisher : Universitas Gadjah Mada

High strength and high conductivity (HSHC) are two intrinsic properties difficult to combine in metallic alloy design because; almost all strengthening mechanisms also lead to reduced conductivity. Precipitation hardening by nano-sized precipitates had proven to be the most adequate way to achieve the optimum combination of strength and conductivity in copper based alloys. However, established precipitation strengthened Cu- alloys are limited to very dilute concentration of solutes thereby limiting the volume proportion hardening precipitates. In this work, we report the investigation of the reprocessing of higher Cr concentration Cu- based alloys via rapid solidification. It is found that the rapid solidification in the as-cast ribbon imposed combined solution extension and ultra-refinement of Cr rich phases. X-ray diffraction evidences suggest that the solid solution extension was up to 6wt%Cr. Lattice parameters determined confirmed the many folds extension of solid solution of Cr in Cu. Thermal aging studies of the cast ribbons indicated that peak aging treatments occurred in about twenty minutes. Peak aged hardness ranged from about 200 to well over 300Hv. The maximum peak aged hardness of 380Hv was obtained for alloy containing 6wt.%Cr but with conductivity of about 50%IACS. The best combined strength/conductivity was obtained for 4wt.%Cr alloy with hardness of 350HV and conductivity of 80% IACS. The high strengths observed are attributed to the increased volume proportion of semi-coherent Cr rich nano-sized precipitates that evolved from the supersaturated solid solution of Cu-Cr that was achieved from the high cooling rates imposed by the ribbon casting process. The rapid overaging of the high Cr concentration Cu-Cr alloy is still a cause for concern in optimising the process for reaching peak HSHC properties. It is still important to investigate a microstructural design to slow or severely restrict the overaging process. The optimum HSHC property reported here is a rare combination of high strength (>350Hv ~ 900MPa) and conductivity (50 – 80% IACS) found in metallic alloys.

A SENSITIVE ASSAY FOR NON-SPECIFIC N-METHYLTRANSFERASE ACTIVITY IN RAT TISSUES BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY ELECTROCHEMICAL DETECTION Dawan Shimbhu; Kohichi Kojima; Toshiharu Nagatsu
ASEAN Journal on Science and Technology for Development Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Phenylethanolamine N-methyltransferase (PNMT) and non-specific N -methyltransferase (EC 2.1.1.28) catalyze the N-methylation of aromatic amines. PNMT is specific for phenylethanolamines such as noradrenaline (NA). and catalyzes the step in catecholamine biosynthesis, forming adrenaline (AD) from NA. PNMT activity is high in adrenal gland, whereas non-specific N-methyltransferase is distributed in various tissues such as the lungs. Borchardt et al. first reported a method to detect PNMT activity by high-performance liquid chromatography electrochemical detection (HPLC-EICD), which could demonstrate the activity only in the adrenal medulla and hypothalamus. Recently, Troeewicz et al. reported a highly sensitive assay method for PNMT using HPLC-EICD by which the activity in all regions of rat brains could be measured. The activity of non-specific N-methyltransferase in brain regions and peripheral tissues of the rat could be detected by a radioassay. However, there has been no repot on an assay method for non-specific N-methyltransferase using HPLC-EICD. In this paper, we describe a highly sensitive assay procedure for the activity of non-specific N-methyltransferase by high-performance reversed-phase ion pair chromatography with electrochemical detection. By this method, the non-specific N-methyltransferase activity could be determined in various rat brain regions and peripheral tissues.

FUSION DECISION FOR A BIMODAL BIOMETRIC VERIFICATION SYSTEM USING SUPPORT VECTOR MACHINE AND ITS VARIATIONS Teoh, A.; Samad, S.A.; Hussain, A.
ASEAN Journal on Science and Technology for Development Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

This paw presents fusion detection technique comparisons based on support vector machine and its variations for a bimodal biometric verification system that makes use of face images and speech utterances. The system is essentially constructed by a face expert, a speech expert and a fusion decision module. Each individual expert has been optimized to operate in automatic mode and designed for security access application. Fusion decision schemes considered are linear, weighted Support Vector Machine (SVM) and linear SVM with quadratic transformation. The conditions tested include the balanced and unbalanced conditions between the two experts in order to obtain the optimum fusion module from these techniques best suited to the target application.

THERMAL PERFORMANCE PREDICTION OF PLASTICS BALL GRID ARRAY (PBGA) USING ARTIFICIAL NEURAL NETWORK Leong, C.H.; Azid, I.A.; Seetharamu, K.N.
ASEAN Journal on Science and Technology for Development Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Artificial Neural Network (ANN) based on feed-forward backpropagation model is used to predict junction temperature in PBG A package. The limited results obtained from FEM (using IDEAS software) are used to train the neural network. The effect of source power, substrate and mold compound thermal conductivity, die size, substrate thickness and air velocity on junction temperature and thermal resistance has been investigated using ANN. The predicted junction temperature using ANN agrees closely with the prediction from FEM. ANN method takes a small fraction of the time and effort compared to that required by HEM for prediction.

ANALYSIS OF QUALITY COSTS FOR STATISTICA QUALITY CONTROL PLANNING N. Chiadamrong; C. Thaviwatanachaikul
ASEAN Journal on Science and Technology for Development Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Quality has become one or the most important force leading to organizational success and company growth in national and international markets. The return-on-investment from strong and effective quality programs is providing excellent profitability results in firms with effective quality strategies. Due to the wide variation in quality results, the search for the genuine keys to success in quality has become a matter of deep concern to management of companies. This paper suggests a way to quantifying quality costs. As a result, the appropriate quality strategies can be adjusted and set to match with each company situation based on the categorization of the quality costs suggested. This outcome can, then, be used as a guideline for manufactures in setting their suitable quality program, which establishes the proper balance between the costs and customer services.

Page 28 of 48 | Total Record : 477

26 27 28 29 30

Filter by Year

1984 2022

Filter By Issues

All Issue Vol. 39 No. 3 (2022): Land, Energy, and Water Resources Vol. 39 No. 2 (2022): Green Economy Vol. 39 No. 1 (2022): Community Resilience Vol. 38 No. 3 (2021): Embrace Potential Vol. 38 No. 2 (2021): Repurpose & Redefine Vol. 38 No. 1 (2021): A New Perspective on Development Vol. 37 No. 3 (2020): Movement Vol. 37 No. 2 (2020): The Perennial Quest Vol. 37 No. 1 (2020): Earth, Water & Fire Vol. 36 No. 1 (2019): Vol 36 No 1 (2019) Vol. 36 No. 3 (2019): Ahead of the Storm Vol. 36 No. 2 (2019): Across the Archipelago Vol. 35 No. 1-2 (2018): Extent of transfer of alien invasive organisms in South/Southeast Asia regio Vol. 35 No. 3 (2018): Developments in Nuclear Techniques in the Treatment of Cancer Vol. 34 No. 2 (2017): Vol 34 No 2 (2017) Vol. 34 No. 1 (2017): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 33 No. 2 (2016): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 33 No. 1 (2016): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 32 No. 2 (2015): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 32 No. 1 (2015): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 31 No. 2 (2014): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 31 No. 1 (2014): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 30 No. 1-2 (2013): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 29 No. 2 (2012): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 29 No. 1 (2012): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 28 No. 2 (2011): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 27 No. 1 (2010): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 26 No. 1 (2009): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 25 No. 2 (2008): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 25 No. 1 (2008): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 24 No. 1-2 (2007): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 24 No. 4 (2007): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 1-2 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 4 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 23 No. 3 (2006): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 22 No. 4 (2005): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 21 No. 1 (2004): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 20 No. 3-4 (2003): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 20 No. 1 (2003): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 19 No. 2 (2002): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 19 No. 1 (2002): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 18 No. 2 (2001): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 18 No. 1 (2001): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 17 No. 2 (2000): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 17 No. 1 (2000): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 10 No. 2 (1993): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 8 No. 2 (1991): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 7 No. 1 (1990): ASEAN Journal on Science and Technology for Development Vol. 5 No. 2 (1988): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 5 No. 1 (1988): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 4 No. 2 (1987): Vol. 4 No. 2 (1987) Vol. 4 No. 1 (1987): ASEAN Journal on Science and Technology for Development (AJSTD) Vol. 3 No. 1 (1986): Vol. 3 No. 1 (1986) Vol. 2 No. 1 (1985): Vol. 2 No. 1 (1985) Vol. 1 No. 1 (1984): Vol. 1 No. 1 (1984) More Issue

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name -

Contact Email -

Phone -

Journal Mail Official -

Editorial Address -

Location Kab. sleman, Daerah istimewa yogyakarta INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. sleman,

Daerah istimewa yogyakarta

INDONESIA