Faculty of Engineering and Built Environment
Universiti Kebangsaan Malaysia

Volume 4 (1992)

Table of Contents

No. Article Detail
1. Measurement of Damping Capacity of Pultruded Glass FibreReinforced Composite by Forced Vibration Technique
Nordin JamaludinAbstract
The effect of strain amplitude and frequency on the loss factor of glass fibrereinforced composite (GFRC) have been investigated by forced vibrations of double cantilever rod specimens. The tests were conducted at room temperature in the frequency range of 70Hz to 320Hz and at atmospheric pressure since the effect of air damping on the rod shape specimens is likely to be small. The measured loss factor is independent of the maximum strain amplitude and increases significantly with frequency. These results indicate that pultruded GFRC has relatively high damping value
download buttonPage 3-12
2. Designing 68008 Emulator Using the VME68K8/CPU-1 Board
Zainol Abidin Abdul RashidAbstract
Emulators is an essential tool in designing microprocessor based systems. Its value lies in its functional and electrical similarity with the actual processor in the target system. This paper describes the design of a 68008 emulator for emulating any Motorola 68008 microprocessor based system. The emulator is designed as add-on version by modifying the existing 68008 microprocessor based systems, which is the VME68K8/CPU-l board. This add-on emulator is simple to design, able to meet the electrical and functional requirements of a good emulator and is relatively cheap
download buttonPage 13-24
3. Preliminary Studies on the Morphology of Natural Rubber-Polypropylene Blends Using Scanning Electron Microscopy
Che Husna Azhari, Zamri Yusoff & Jaafar SahariAbstract
The morphology of natural rubber/polypropylene (NR/PP) blends were studied using scanning electron microscopy (SEM). The NR/PP blends were produced in varying compositions of NR/PP ratios of 80:20, 70:30, 60:40, 50:50, 40:60 and 30:70. The NR/PP blends were sputter coated with gold and observed under a Phillips 500 SEM at magnifications of 0.326K and 2.5K respectively. Micrographs showed the blends as incompatible polymers with NR domains embedded in a continous PP matrix. At higher NR loadings, the NR domains were observed to be fibrils interspersed continously in the PP matrix whilst at lower loadings the NR phase was scattered in distinct granular domains. Models of the NR/PP blends were postulated frorn the micrographs obtained
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4. Kinetics Of Devolatilization Of Oil Palm Solid Waste Using Thermo-Gravimetric Analysis
Abdul Halim Shamsuddin & Paul T. WilliamsAbstract
The kinetics of the devolatilization of oil palm fibres and shells have been determined in a Thermo-Gravimetric Analyser (TGA). The TGA data indicate that the devolatilization process begins around 200°C and terminates around 600°C. The Differential Thermal Analysis (DTA) data indicate the existence of two different rates of devolatilization with the turning point at around 350°C. The temperature at which the maximum rate of weight loss occurs are around 315°C and 380°C. The kinetic parameters, namely the activation energy and the ftequency factor, are determined assuming a first order reaction. The data are compared to that of pure cellulose
download buttonPage 35-42
5. Distribution of Ga Vacancies in Zn Diffused GaAs
Zahari Mohamed Darus & Iftekhar AhmedAbstract
A detailed discussion on the distribution and the characteristics of vacancy profiles in Zn diffused GaAs is presented in this paper. Vacancies are consumed during the diffusion process, creating short-fall in the equilibrium vacancy concentration. The crystal tries to recover this short-fall by vacancy diffusion and vacancy generation process. In course of time, the depth in the vacancy short-fall decreases, but this short-fall propagates deeper into the crystal
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6. Kajian Aliran Tepu Persimpangan Berlampu Isyarat di Lembah Kelang (Study of Saturation Flow at Signalized Intersections in Kelang Valley)
Ismail Abdul RahmanAbstract
This research is aimed at studying factors that influence saturation flow at signalized intersections in Kelang Valley. In this study local drivers and vehicles characteristics, geometric design and traffic regulations are taken into considerations. The results show that the relationship introduced by Webster and Cohbe, gives an underestimated value of saturation flow at any given approach. Comparison between three most frequently used models i.e. Webster and Cohhe, Akcelik and Ellson and Kimber shows that Kimber model gives a more realistic estimation of the effects of turning radius magnitude and percentage of turning vehicles on the local saturation flow. Passenger-car unit values recommended by Webster and Cohbe give a close estimation to real conditions for all types of vehicles except for buses
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7. Penghidrogenan Selanjar Olein Sawit dengan Menggunakan Mangkin Platinum Tersokong (Continuous Hydrogenation of Palm Olein by Using Supported Platinum Catalyst)
Che Husna Azhari, Sufian Ali & Wan Mohtar Wan YusoffAbstract
A catalytic hydrogenation rig based on a continuous flow process regime was designed, fabricated and installed to investigate the 3 phase reaction of palm olein. The three phases involved were liquid (palm olein) gas (hidrogen) and solid (Pt supported on Nylon-66). The microreactor (catalyst loading of 1.0g) was operated under isothermal conditions. The temperature of operation was in the range of 110 °C – 190 °C. Reactant flow rates were maintained at 0.32 mI/min for palm olein and 93.0 ml/min for hydrogen. The products of hydrogenation were analysed using gas chromatography. The extent of reaction as well as overall rate was measured from values of drop in iodine value. The products of hydrogenation were observed to be selective to the C18:1 and C18:2 fractions. The overall activation energy was found to be 52.07 kJ/mol, whilst that of the linoleic and oleic fractions were 27.07 kJ/mol and 49.85 kJ/mol respectively. The selective reaction mechanism was explained using the cluster model. In the model, the linoleic fractions were thought to be adsorbed on to active sites and thence converted to the oleic fractions. Further saturation was hindered
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8. Performance and Working Space Requirement for Passive and Semiactive Automobile Suspension
Mohd. Jailani Mohd. NorAbstract
In this paper computer simulation is used to study the performance of an automobile suspension system. The effect of tyre stiffness and unsprung mass on the performance in terms of riders comfort and the maximum working space requirement of the suspension system are also studied. Next, simple “on-off” semi-active control rules are applied to the damper. These rules have been able to reduce the maximum working space required when compared to the passive suspension system. But, in terms of riders comfort the passive system is more superior. Finally, modified control rules are introduced and comparison on the performance and working space requirement are made with the suspension systems mentioned earlier. In general, the modified control rules have been able to increase riders comfort but larger working space are required
download buttonPage 71-82