Applied Mechanics and Materials Vol. 819

Abstract: Common hydraulic system using hydraulic oil as their working medium but there is an application using water due to high accessibility and environmentally concern.Water hydraulic is an attractive technology to use water as the pressure medium in hydraulic system. In this paper, water hydraulic system is design and develops that capable to use water as pressure medium. Water is used to provide clean environment and safe for the mobile purpose. The system includes electric motor, water pump, directional control valve, pressure control valve and motor hydraulic. Some of water challenged as the pressure medium in hydraulic system were considered during build and design the system to minimize the bad effect of water in hydraulic system. Besides, the arrangement of hydraulic components on the test rig also considered to optimize the water hydraulic system performance. Water hydraulic system performance was analyzed by measured maximum pressure produced from water pump and system efficiency. Others, the effect of temperature increment in water hydraulic system also analyzed to optimize operation time.

Abstract: A lotus type-porous copper will be used to substitute wick materials from tabulate coral capillary for heat pipe applications. The lotus type-porous material are normally fabricated using Gasar process, in which unidirectional solidification was applied to the metal-eutectic systems to obtain long cylindrical pores in the direction of solidification. A new process is proposed to fabricate the lotus type-porous material using slip casting and sintering. As an initial work, this paper is aimed to obtain appropriate processing parameters of fabrication of lotus-type porous copper using slip casting and sintering techniques. Nylon strings were used as pore formers to form cylindrical pores. They were coated with copper slurry consisting of copper powder and binding agent. The coated nylon strings were arranged in a mold and the slurry were poured. After drying, these castings were sintered at various sintering temperatures and sintering times. The results showed that starch as the binding agent is superior to PVA. The mixture of starch-water with starch content of 97%, the copper slurry with copper content of 50% by volume, the copper powder size of 200 µm, the sintering temperatur of 900°C, and the sintering time of 60 minutes are able to produce lotus-type porous copper similar to that produced through Gasar process.

Abstract: Malaysia has been acknowledged as one of the largest producer and exporter in the production of oil palm biomass. This is not surprisingly that industry contributes massive amount of the waste such as empty fruit bunches, palm mesocarpfibre, and palm kernel shell. This abundance of oil palm by-products make them an attractive source of raw material for the production of activated carbon. The activated carbon has been widely used in variety industries such as bio-catalyst, removal of toxic substance, purification of liquid and gas as well as catalyst support. The comparison of characteristic of oil palm activated carbon produced via microwave and conventional heating has been discussed in this paper. The characterization of the activated carbon includes elemental analysis, the Brunauer-Emmet-Teller (BET) surface area as well as Scanning Electron Microscopy (SEM) has been analyzed in this study.Hence, from the result, it shows that the SEM micrograph of oil palm shell (OPS) activated carbon prepared via microwave heating by using chemical activation produced the clearly and uniformly pore compared to full cavity and not well formed of pore in oil palm shell (OPS) activated carbon via conventional heating.

Abstract: A series of wet braking tests has been performed using two different pad materials. Brake tests were conducted in different operating conditions i.e. dry, humid air and wet environment in which both pad samples were tested against grey cast iron disc at certain sliding speed and contact pressure. Wear analysis was performed to find correlation between presence of water and changes in brake pad wear characteristics. The results revealed that regardless of the frictional behaviour, wear rate for both pad materials tested at humid air and wet braking is significantly lower than in dry results.

Abstract: Photovoltaic systems have become recently the most attractive and promising technology compared with other solar energy conversion devices. Solar energy reaches the earth’s surface in wavelengths between 0.300 and 2.50 μm. Silicon based photovoltaic systems convert only the wavelength between 0.35 to 0.82 μm of solar energy to electricity. The rest of incident solar radiation will be converted to heat, which will increase the operating temperature of the device and decrease the output power and efficiency. Maintaining the operating temperature of the PV systems at low and desired value was the main emphasis of different researches through the last decades. In this research, a special transparent glass cover (STGC) was used in order to cool down the photovoltaic module and, therefore, increase the output power and the efficiency of the module. The result showed that STGC led to 2.75% improvement in open circuit voltage, 9.6% increase in short circuit current, 26.4% increase in the output power, and 3% increase in the efficiency of the module.