Skip Navigation LinksVolume : Volume 8 No.1 1999

  
  
  
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review_of_ageing_behaviour_of_yttria-tetragonal_zirconia_polycrystals_y-tzp_part_2_ageing_mechanism.pdfREVIEW OF AGEING BEHAVIOUR OF YTTRIA-TETRAGONAL ZIRCONIA POLYCRYSTALS (Y-TZP): PART 2, AGEING MECHANISM
  
ABSTRACT:
This second ageing paper is focused mainly on the various mechanisms used to explain the low temperature degradation phenomenon in Y-TZP ceramics. An understanding of the ageing phenomenon in Y-TZP ceramics has been established and discussed. In general, although the theories are contradictory in nature, it has been universally accepted that the cause of degradation was due to the tetragonal to monoclinic phase transformation. Water has been identified as the key player in triggering the phase transformation.

AUTHOR:
Ramesh Singh
Year: 1999
investigation_of_turbulence_structures_in_liquid_liquid_two-phase_flow.pdfINVESTIGATION OF TURBULENCE STRUCTURES IN LIQUID/LIQUID TWO-PHASE FLOW: PART 1: LIQUID MEAN VELOCITY AND TURBULENCE MEASUREMENT
  
ABSTRACT:
The liquid  phase turbulent structure of kerosene/water, bubbly upflow in  a circular pipe has been experimentally investigated.  Liquid phase velocities and turbulent stress were simultaneously measured, using single normal boundary layer hot-film anemometer probes. A highly accurate digital process, based on combination of amplitude and threshold  methods, was developed to identify the phases. Methods are described and discussed for the evaluation of longitudinal  mean velocity, normal stress, autocorrelation and energy spectrum. Finally typical results for a vertical up-flow of bubbly kerosene/ water mixtures are presented.

AUTHOR:
Jusni Ali and Yahya Sukirman
Year: 1999
interfacial_reaction_between_sic_and_aluminium_due_to_extrusion_and_heat_treatment_process.pdfINTERFACIAL REACTION BETWEEN SiC AND ALUMINIUM DUE TO EXTRUSION AND HEAT TREATMENT PROCESS
  
ABSTRACT:
Chemical interaction between aluminium (Al) and silicon carbide (SiC) produces aluminium carbide (Al4C3) which presents potential problems in  the production and application of AI/SiC Metal Matrix Composite (MMC). The (Al4C3) formed can reduce material properties such as strength in the MMC. This research work investigates the  interface  reaction in  Al 7075/SiC MMC made through  hot extrusion process. Mixed Al 7075/SiC MMC powders were pressed at 300°C and extruded at 500°C, with a reduction ratio of 20:1. The extruded MMC was then heat-treated in air at various temperatures from 560°C, 600°C,  640°C, 700°C to 800°C in  order to observe the interface reaction of the MMC materials. The heat-treated MMCs were then analyzed under the optical microscope, X-ray Diffraction (XRD) Spectroscope and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray (EDAX) attachment to observe the interface reaction within the MMCs. This investigation confirms there was interface reaction between SiC and aluminium.

AUTHOR:
Junaidah Jai, Fauzi Ismail, Samsiah Sulaiman, Patthi Hussain and Azmi Idris
Year: 1999
esters_in_water_oil_microemulsion_stabilised_by_anionic_surfactant_and_a_medium_chain_alcohol.pdfESTERS IN  WATER/OIL MICROEMULSION STABILISED BY ANIONIC SURFACTANT AND A MEDIUM CHAIN ALCOHOL
  
ABSTRACT:

Four esters were applied in  the  W/0 microemulsion phase of water/ sodium dodecyl sulphate (SDS): hexan-1-ol (35:65)/hydrocarbon (n-decane and p-xylene) to study their solubility behaviour in such system. The esters used were ethyl-n-butyrate, ethyl benzoate, methyl oleate and methyl linolenate. The solubility of the esters was observed to be dependent of the ratio of the SDS: hexan-1-ol and hydrocarbon. A higher solubility of the esters was observed in a larger ratio with ethyl-n-butyrate showing the highest solubility. The solubility was, however, inversely proportional to the water content of the  microemulsion. The type  of hydrocarbon was observed to  have little  or no appreciable effect on the solubility of the esters.

AUTHOR:
Hamdan, Suhaimi, Laili Che Rose, Faujan Ahmad, Dzulkefly Kuang and Ambar Yarmo
Year: 1999
development_of_superconductor_applications_in_the_power_system_industry.pdfDEVELOPMENT OF SUPERCONDUCTOR APPLICATIONS IN THE POWER SYSTEM INDUSTRY
  
ABSTRACT:

The discovery of high temperature  superconductors has revived interests  for  the  development of superconductive devices for  power system applications. Substantial progress has been made towards  the  consequent acceptance of superconductive power components into the  power system with further improvements to  material fabrication and refrigeration system aimed at justifying its application and economic feasibility. Commercialisation of these devices is dependent on their ability to compete cost effectively in  the marketplace with prevailing technology.  In  addition, the  operational advantages and hoped for improvements in the reliability of superconductors are also key factors for potential widespread superconductor applications in  the  future  utility market. The most significant development in  countries (U.S.A., Japan, Germany) with the largest superconductor R&D programmes are highlighted with relevance to the device discussed. A discussion of the significance of these development programmes to the Malaysian power and energy sector is also presented at the end of this article.

AUTHOR:
M. Moghavvemi, S.S. Yang and A.M.R. Mustafizur
Year: 1999
buoyancy_effect_of_purge_gas_in_the_determination_of_carbon_black_content_in_polyethylene.pdfBUOYANCY EFFECT OF PURGE GAS IN THE DETERMINATION OF CARBON BLACK CONTENT IN  POLYETHYLENE
  
ABSTRACT:
Oxygen and air have been interchangeably used as the purge gas in  the determination of carbon black content in  polyethylene. This study shows that accuracy of the  carbon black filler content is  significantly affected by the choice of oxygen as the purge gas used to oxidise the carbon filler. It is believed that the difference in the density of the oxygen give rise to the buoyancy effect. Air, having closer density to the initial nitrogen purge gas in the analysis, is the better choice for purge gas for accuracy of analysis and reproducibility of results.

AUTHOR:
M.Y. Ahmad Fuad, Z. Ismail, S. Rahmad and H. Hanim
Year: 1999