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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 8 Documents

Search results for , issue "Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)" : 8 Documents clear

THE EFFECTS OF PALMVITEE ON HUMAN NASAL SEPTAL CHONDROCYTES CULTURE EXPANSION AND CARTILAGE RECONSTRUCTION B.H.I. Ruszymah; B.S. Aminuddin; A. Gapor; H. Fuzina
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Palmvitee may act as a beneficial supplement to cartilage tissue engineering which is currently still has certain limitation on chondrocyte expansion and dedifferentiation. Our objectives in thisstudy were to evaluate the effects of Palmvitee on the growth kinetic and phenotype gene expression of human nasal septal chondrocytesin monolayer expansion as well as cartilage reconstruction via tissue engineering technology. Human chondrocytes were cultured inmediums containing various Palmvitee concentrations. Among the different test groups, the medium containing Palmvitee at 3 ?g/ml supported the highest chondrocyte growth rate. The gene expression in monolayer chondrocytes culture supplemented with 3 ?g/ml Palmviteedemonstrated similar results as in control. Cultured chondrocytes from the medium added with 3 ?g/ml Palmvitee were then mixed with Pluronic F127 for cartilage reconstruction in nude mice model. Palmvitee supplementation supported the engineered cartilage development as shown in the histological and gene expression analysis on engineered tissue after 8 weeks of implantation. Therefore, Palmvitee at 3 ?g/ml is beneficial for the human nasal septal chondrocytes monolayer expansion and cartilage engineering.

MEDIUM OPTIMIZATION FOR THE PRODUCTION OF BIOMASS BY Cunninghamella sp. 2A1 USING RESPONSE SURFACE METHODOLOGY Siti Aminah Sulaiman; Aidil Abdul Hamid; Wan Mohtar Wan Yusoff
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

A statistical design approach has been used to optimize the production of biomass byCunninghamellasp. 2A1, evaluated based on lipidless biomass. A 23full factorial centralcomposite design (CCD) was chosen to study the combined effects of three factors; ammoniumtartrate, peptone and glucose concentrations. The p-value for each factors was < 0.05 suggestingthat these factors have significant effect on the production of lipidless biomass. The productionis represented by a linear model with p-value < 0.0001. The optimized medium consists of 3.86g/l ammonium tartrate, 55.84 g/l glucose and 7.73 g/l peptone predicted 16.83 g/l lipidlessbiomass. Results from four replications based on the optimized medium produced 18.48 g/llipidless biomass, which are in close agreementwith the predicted value. The coefficient forglucose was the highest indicating it as the most significant factoraffecting lipidless biomassproduction.

MICROBIAL DEGRADATION OF ENDOSULFAN IN AGRICULTURAL SOILS B.S. Ismail; A.O.S. Enoma
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

A study of the degradation of endosulfan (6, 7, 8, 9, 10, 10-hexachloro – 1, 5, 5a, 6, 9, 9a –hexahydro – 6, 9- methano – 2, 4, 3 – benzodioxanthiepin 3 – oxide) in Malaysian sandy loam and clay soils was carried out using a radioisotopic technique under laboratory conditions. It was demonstrated that endosulfan possessed long half-lives of 433, 495 and 462 days in aerobic sandy loam, aerobic clay and anaerobic clay soils respectively. Endosulfan degrades faster in non-sterile than in sterile soils. This study indicates that microorganisms are involved in the degradation of endosulfan. In general, degradation of the pesticide was relatively higher in the clay soil than in the sandy soil. Apart from the parent compounds, ?- and ?-isomers, the degradation products include endosulfan sulphate and three minor unidentified products.

ON THE DENSE FAMILIES IN THE RELATIONAL DATAMODEL Vu Duc Thy; Nguyen Hoang Son
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

In this paper, dense families of relation schemes are introduced. We characterize minimal keys of relation schemes in terms of dense families. Note that, the dense families of database relations were introduced by Jarvinen [6]. We prove that the set of all minimal keys of a relation scheme s= (U, F) is the transversal hypergraphs of a hypergraph D– {?}, where Dis any s-dense family. We give a necessary and sufficient condition for an abitrary family to be s-dense family. We also present some dense families of relation schemes. Furthermore, in this paper, we also study antikeys by means of dense families. We present connections between antikeys and a dense family of relation schemes. Finally, we study the time complexity of the problem finding antikeys.

SPOT WELDING COPPER - 1% Cr ELECTRODE TIPS PRODUCED VIA EQUAL CHAN NEL ANGULAR PRESSING L.B. Hussain; Ali A. Aljuboury; M.A.M. Gebril; Nurulakmal Moh Sharif
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

A sharp 120o Equal channel angular pressing (ECAP) was applied at room temperature to refine the grains sizes of pure copper and copper - 1% Chromium alloy for spot welding electrode tips application. Initially deformation behavior was investigated with the position using colorful plasticine as work piece followed by copper alloy. It was found the deformation at the central part of the work piece is heavily sheared than the outer part. Optical and Scanning electron microscopy were used to study the progress of grain refining under the influence of rotation and number of passes during pressing. The influence of elongated fibrous nano graines on electrical conductivity and hardness were discussed. Shear test of spot welded 303 stainless steel indicated that nano structural Cu-1% Cr electrode tips used showed superior results compared to commercial electrodes.

WATER-SOLUBLE N -SUBSTITUTED CHITOSAN DERIVATIVES Ph. Le Dung; D.T. Thien; N.T. Dong; T.T.Y. Nhi; N.T. An
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Many water-solubleN-substituted chitosan derivatives have been prepared having the typical -NH-CH2- linkage. Both the Michael reaction and alkylation with monochloroacetic acid at pH 8- 8.5 offer relatively simple ways for their synthesis.

STUDY ON MOISTURE-CUR ED POLYURETHANE AS UNDERCOATING LAYER FOR METALLIZATION M.N. Mohamad Ibrahim; M.E. Izat; A.R. Wahida; C.S. Sipaut
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29037/ajstd.165

In this work a technique of metallizing substrate via electroless plating using moisture-cured polyurethane (MCPU) system as the undercoat is presented. MCPU prepolymer was prepared by mixing polyethylene glycol divinyl ether and diphenylmethane-4, 4’-diisocyanate in 1:1 ratio. The effects of etching time as well as curing period on the surface characteristic of MCPU undercoating were investigated. Contact angle measurements, FTIR and SEM were employed to study the changes on the surface of the treated MCPU undercoatsprior to electroless nickel plating. Electroless plating was performed using nickel bath and visual inspection was performed after completing the electroless plating cycles. Relative increase in wettability of the treated MCPU was observed. The surface became hydrophilic after subjecting to mild etching for 1 minute. SEM analysis revealed different pitted structures on the treated MCPU that were cured at different periods. FTIR analysis of the treated MCPU showed some chemical changes marked by the presence of free hydroxyl group and decrease of CH (methylene), urethane C=O, urethane amide and ether peaks. FTIR also showed the sign of further NCO reaction, which indicates by the decrease of NCO peak and increase of NH and urea C=O peaks. The standard pull-off testing method (ASTM D 4541) was employed to evaluate the adhesion strength of nickel deposits coated on MCPU undercoating layer.The test results revealed that curing period and etching time influence the adhesion performance.The results also show that at a selected curing period, prolong etching time will decrease the adhesion strength. Meanwhile prolong curing period will improve the adhesion strength.

DEVELOPMENT OF HOLE RECOGNITION SYSTEM FROM STEP FILE C. F. Tan; N. Ismail; S.V. Wong; S. Sulaiman; M.R. Osman
ASEAN Journal on Science and Technology for Development Vol. 22 No. 3 (2005): ASEAN Journal on Science and Technology for Development (AJSTD)
Publisher : Universitas Gadjah Mada

This paper describes the development of Hole Recognition System (HRS) for Computer-Aided Process Planning (CAPP) using a neutral data format produced by CAD system. The geometrical data of holes is retrieved from STandard for the Exchange of Product model data (STEP). Rule-based algorithm is used during recognising process. Current implementation of feature recognition is limited to simple hole feat ures. Test results are presented to demonstrate the capabilities of the feature recognition algorithm.

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