Advanced Materials Research Vols. 931-932

Abstract: The aims of this study are to investigate flow characteristics in pulse jet combustor and heat transfer characteristics of impinging jet from pulse jet combustor. The combustor is Helmholtz type which has single combustor chamber and single tailpipe. The inner diameter (D) of tailpipe was 47 mm and tailpipe length was about 16D. The effect of number of air inlets: single inlet, double inlets with 90^o apart, double inlets with 180^o apart and triple inlets with 90^o apart on flow and heat transfer characteristics were studied. A water cooled heat flux sensor was applied to measure heat transfer rate on the surface at stagnation point. The jet-to-plate distance was varied at L=1D, 2D, 4D, 6D and 8D. Two of pressure transducers were mounted on the wall of combustion chamber and on the wall of tailpipe at 4D from tailpipe outlet to measure pressure simultaneously. It is found that the variation of pressure near the tailpipe outlet is strongly depended on air inlet configurations. The pressure variations in pulse jet combustor could be preliminary related to the temperature and velocity of jet from tailpipe and heat transfer rate on jet impingement surface.

Abstract: This paper investigates the thermal performances and heat gain reduction of a new roof tile design referred as Ventilated Roof Tile (VRT) compared with an ordinary corrugated concrete roof tiles (CCR). The outside dimension of each small house was 1.70 x 1.70 x 2.85 m³ (W x L x H) and inside dimension was 1.50 x 1.50 x 2.20 m³. The volume of each room was 4.95 m³. The gable roofs slope were 25^o and surface area of VRT was 2.58 m² per each side facing north and south. The VRT tile composed of upper cement plate 40 × 40 cm² and lower cement plate 30 x 40 cm². Between plates was 3 cm thickness air gap. The experimental results showed that the top surface of VRT was lower than CCR about 2.10°C for average temperature (from 6:00 18:00) and made VRT room temperature lower than CCR about 1.41°C for average temperature. VRT could reduce heat gain with air flow rate through the roof tiles gaps varied following the solar radiation, during time 8:00-17:00 the natural ventilation varied from 0.003-0.014 m³/s (10.6-50.0 m³/hr.). Observed that, during 17:00-18:00, the air flow rate is about 0.003 m³/s (10.8 m³/hr.) due to heat accumulated in the attic space and roof tiles.

Abstract: Para rubber solar greenhouse dryer is a one method of drying and it can be responded to requirement of agriculturist on amount of drying product. Present, the dryer was being built many type for made drying agriculture product. The air circulation and temperature scatter havent been used for the dryer built process, which are cause of fungus on product surface and product dehydrate not all over. Therefore, the objective of this research is to study temperature distributes and air circulations inside Para rubber solar greenhouse dryer of incline roof type using computational fluid dynamics method. The result showed that temperature and velocity of air were good distributing all area and havent air cluster under the roof.

Abstract: Water produced along with the crude oil during production and transported together in a pipeline is a common occurrence in a petroleum production system. Understanding the behavior of crude oil-water flow in a pipe is crucial to engineering applications such as design and operation of flow lines and wells, and separation systems. Presently, there was no two phase flow study done on the Malaysian waxy crude oil-water. Therefore, a research work was conducted at the Malaysia Petroleum Resources Corporation Institute for Oil and Gas, Universiti Teknologi Malaysia to study the flow pattern of the Malaysian waxy crude oil-water flowing in a closed-loop system at the ambient condition through a 5.08 cm ID stainless steel horizontal pipeline. The research works comprised fluid characterization and flow pattern observation using a video camera camcorder. Five flow patterns have been identified, namely stratified wavy flow, stratified wavy with semi dispersed flow at interface and oil film, dispersion of water in oil and oil continuous with emulsion, dispersion of oil in water with water continuous, and the newly found semi dispersed flow with semi emulsion at interface and thin oil film. The experimental results could be used as a platform to understand better a more complex case of gas, oil, and water flow in a pipeline, which is of utmost importance in designing optimum surface facilities.

Abstract: Understanding the pressure drop and water holdup of crude oil-water flow in a pipe is crucial to many engineering applications. Free water in contact with the pipes wall can cause erosion or corrosion problems. An experimental research was conducted at the Malaysia Petroleum Resources Corporation Institute for Oil and Gas, Universiti Teknologi Malaysia to study the pressure drop and water holdup of the Malaysian waxy crude oil-water flowing in a closed-loop system at ambient condition through a 5.08 cm ID stainless steel horizontal pipeline. In the research work, water cuts were varied from 0 - 90% with mixture velocities ranging from 0.1 0.8 m/s. The research works comprised fluid characterization, pressure drop, and liquid holdup measurement.The investigations proved that pressure drop increased with flow rates, while the water holdup was found to have decreased slightly at higher water cuts due to the presence of emulsion in the crude oil a challenge when using a waxy crude oil in a two phase flow system. The experimental results can be used as a platform to understand better a more complex case of liquid-liquid two phase flow.

Abstract: Ultrahigh areal density is the key target of hard disk drive technology. Hence, writing field strength from head and switching field, H_sw, of media should be improved. In this work, we propose the one of alternative method to increase data density and reduce H_sw of the media by using tilted easy axis technology for bit patterned media (BPM) at areal density beyond 2.5 Tb/in². Moreover, transition noise and superparamagnetic limit have been eliminated owing to characteristics of BPM. The effect of exchange coupled between adjacent bits, A_dot, of tilted easy axis of BPM is analyzed by micromagnetic simulation software - the object oriented micromagnetic framework based on Landau-Lifshitz-Gilbert equation. The BPM with tilted easy axis perform clearly the reduction of H_sw below perpendicular media and available writing head field. The A_dot of BPM has no effect on decreasing H_sw. Anisotropy and Zeeman energy density of BPM with tilted easy axis are higher and lower than perpendicular BPM, respectively. Thereby, BPM with tilted easy axis have high potentiality to improve H_sw of media at ultrahigh data density.

Abstract: In this paper, we propose a new method to estimate and reduce effectively thermal asperity (TA) in the perpendicular recording channels with state trellis. The proposed method comprises of recursively applying a previous noise estimate to a calculation of a current noise estimate to eliminate the effects of TA from the equalized signal. With partial response a maximum-likelihood detector base on partial-response (PR) target with DC-full component can improve the system performance by more than 50% when TA occurs. Unlike previous studies of TA cancellation or suppression, this method is different because we dont use PR targets with non-dc components and high pass filter.

Abstract: To overcome superparamagnetic limit, microwave assisted magnetic recording (MAMR) is one interesting magnetic recording technology. Therefore, the effect of microwave on magnetization reversal in media should be analyzed. In this work, we propose the MAMR to decrease switching field (coercivity, Hsw) in exchange coupled composite (ECC) media by using the micromagnetic simulation based on the Landau - Lifshitz - Gilbert equation. The Hsw of single layer and ECC media without microwave field is 110.90 and 7.7 kOe, respectively. When the oscillating microwave field is added, Hsw of single layer media with microwave frequency of 2.5 - 40 GHz is lower than 110.90 kOe. Likewise, Hsw of ECC media with microwave frequency of 5 - 16 GHz is lower than 7.7 kOe and has the lowest value of 4.9 kOe at frequency of 10 GHz. The results from this work lead to solve superparamagnetic limit and increase areal density in hard disk drive.

Abstract: This paper describes the two inputs - two outputs control theory. The theory is using the simplify decoupler filter that can reduce the disturbance arising from loop interaction. The system controls both the pressure and flow rate in the closed tank. The media of the process is water. The work includes four important aspects: Designing, Implementation and Test. In this design consist of two parts such as models of the process and decoupler. In this simulation was used a MATLAB to finding a suitable decoupler. In this implementation was used a personal computer, Pressure Transmitter, Magnetic Flow Meter, DP/PA coupler, Convertered IF 303,FI303 and The controller of SIEMENS S7 400 Modules which all of implements was created to control systems by used the technology of PROFIBUS to create a networked control system(NCS). In this test was used to compare performance of the old TITO systems with the new TITO system.

Abstract: In this paper, the electrical properties of materials were evaluated using a microstrip patch sensor. The sensor was designed for the operating frequency in range of 1.5 to 3 GHz on a DiClad 880 substrate with the permittivity of 2.2. The resonant frequency of the design sensor ,as well as the magnitude of the reflection spectra S₁₁, were analyzed and then simulated three-dimensional finite element modeling when,. The result shows that the increase of the dielectric constant (ε_r) and conductivity (σ) of the material under test (MUT) led to the significant change of the resonant frequency. Thus, the resonant frequency may be used to evaluate the moisture content of the agricultural products.