Advanced Materials Research Vols. 622-623

Abstract: The purpose of this work is to determine the drag characteristics and the torque of three C-section blades wind car. Three C-section blades are directly connected to wheels by using of various kinds of links. Gears are used to convert the wind energy to mechanical energy to overcome the load exercised on the main shaft under low speed. Previous work on three vertical blades wind car resulted in discrepancies when compared to this work. Investigating these differences was the motivation for this series of work. The calculated values were compared to the data of three vertical blades wind car. The work was conducted in a low wind speed. The drag force acting on each model was calculated with an airflow velocity of 4 m/s and angular velocity of the blade of 13.056 rad/s.

Abstract: In this paper, various factors that affect the solar cell performances are investigated with emphasis given to the window layer (CdS:O) thickness, operating temperature and light intensity as well as the effect of front contact and BSF layers. Various parameters of solar cells such as quantum efficiency, series and shunt resistance associated with the front contact and BSF materials have been investigated also. Two materials ZnO and SnO₂ were used as front contact and two materials Sb₂Te₃ and ZnTe were used as BSF layers to investigate their effects on ultra-thin cell performances. The results have shown that the BSF layers have no unfavourable effect on cell stability with temperature increase as the cell temperature coefficients with these BSF layers were 0.1% (ZnTe) to 0.3% (Sb₂Te₃). However, the results of the comparisons demonstrate that the best option is Sb₂Te₃ as BSF material, which exhibits lowest series resistance and behaves as an excellent minority carrier mirror whereas ZnTe showed unexpected series resistance problems because of the adverse heterojunction with CdTe.

Abstract: Airfoils have become a combined aspect of human flight as it has evolved over the last century. As the design of each airfoil determines many aspects of its use in the real world, all significant characteristics must be analyzed prior to implementation. The aerodynamic effects of pressure, drag, lift, and pitching moment are used to evaluate the behavior of the airfoil. The airfoil shape is expressed analytically as a function of some design parameters. The NACA 0012 and NACA 2412 are used with design parameters that control the camber and the thickness of the airfoil. Singularity method is the way to determine velocity distribution and pressure distribution of the airfoils. In order to apply it to the potential flow, Kutta condition and kinematic flow condition must be satisfied. It is expedient to treat a very thin profile. In this work, three vertical blades wind car, and directly connected to wheels by using of various kinds of links, and gears are used to convert the wind energy to mechanical energy to overcome the load that rotates the main shaft. The purpose of this work is to determine the torque, lift and drag forces of the different types of NACA airfoils that can be used in electric power generating or running our wind car. This was done by calculating of pressure distribution over the upper and lower surface of the airfoil to calculate the velocity distribution, lift and drag coefficient.

Abstract: The awareness on biodiesel in developing countries in the recent times has been increased. Several activities have been picked up for its production especially with a view to boost the rural economy. In the present investigation biodiesel was prepared from jatropha curcas seed oil (non edible oil). Before exploiting any plant for industrial application, it is imperative to have complete information about its biology, chemistry, and all other applications so that the potential of plant could be utilized maximally. Biodiesel was prepared by transesterification process of jatropha oil with methanol in heterogeneous system, using heterogeneous catalyst. The heterogeneous catalysts are environment friendly and render the process simplified. Calcination process was followed by the dependence of the conversion of jatropha oil on the reaction variables such as the catalyst loading; the molar ratio of the methanol to oil, reaction temperature agitation speed and the reaction time was studied. The conversion was over 89% at a reaction temperature of 70oC and molar ratio 12:1. Finally, Jatropha oil methyl esters was characterized to test its properties as fuels in diesel engines, such as viscosity, flash point, cetane number. Results showed that biodiesel obtained under the optimum conditions is an excellent substitute for fossil fuels.

Abstract: Thailand, electricity production form biogas has been interested for replacement nuclear and fossil power plants. Current status of electricity production from biogas is 155 MWe, and more potential of current capacity is 380 MWe. Additional, energy crops have a potential for another source of biogas. For this study, electricity production to 1000 MW was determined. Napier grass was considered, high growth rate and high production yield. Napier grass 190,000 acre can produce 1000 MW electricity. And economic analysis of electricity production 1 MW was studied, these results show that biogas for electricity 1MW power plant project is not economic under current condition in Thailand.

Abstract: The non conventional energy has derived mainly from the biomass which is utilized towards the sector of rural economy. The North-East India has consumed in from firewood cow dung and crop residues are used for gas production and it can replace much other energy oil from biogas production. The economic analysis of biogas plants has showed that the installation of biogas is economically very important. This paper throws light on the techniques of biogas production and its use in North-East India.

Abstract: Complexity in modeling an underwater thruster analytically, leave system identification approached a good option on developing accurate dynamic model for underwater thruster. Nonlinearity of the system due to fluid solid interaction such as, hydrodynamic force hitting the propeller blade make the system identification became a trivial task. This paper presents nonlinear modeling and identification of the underwater thruster from input–output measurement. The system was fully submerged, and current was varied as the input and the output thrust was measured using load cell. Nonlinear Hammerstein method is chosen for identification of the system. The results are numerically and graphically presented. The nonlinear system identification with second order linear dynamics gave the best result, where is the model, can fit up to 82 % of the real response of the thrust. The finding of the model can be utilized in the future to improve underwater vehicle performance by developing optimum control algorithm.

Abstract: As most of today’s a continuously variable transmission (CVT) adopt an electro-hydraulic control system, the role of electronically controlled solenoid valves play an important stature. This paper presents a dynamic modeling and simulation of CVT hydraulic system using Matlab-simulink package and analyzes the dynamic characteristics of the CVT hydraulic system in frequency domain.

Abstract: Contractile water jet thruster is an alternative method for Autonomous Underwater Vehicle (AUV) locomotion as well as for the AUV’s manoeuvrability control. Currently, studies on contractile water jet thruster focus more on the thrust force performance and its efficiency, such as the characterization of vortex ring formation process, the slug model L/D ratio and the influence of the thrust performance on the AUV. The aim of this paper is to discuss the fluid flow behaviour in the thruster during contraction process under different actuation frequency. This research utilized Ionic Polymer Metal Composite (IPMC) as the actuators instead of electric motor for the contractile function. The result shows that the Reynolds number of the intake flow has negative linear relation with the actuation frequency.

Abstract: Since the invention of the internal combustion engines, Automotive engineers are finding ways to increase engine power that one way is supercharger. It was developed to assist internal combustion engines in improving performance and power of the engine, But these plans have deficiency as Intercoolers and Turbo Lag and etc.but this new designed system to cause launching a diaphragm pump by use of the linear motion in suspension system then compressed air is stored in tank and by using the directional control valve 3/4 with the states of off-sport 1and sport 2 we can increase engine power. The results of torque ,BSFC(Brake specific fuel consumption) and indicator diagrams(p-v) show increased horsepower And the advantages of this plan are that we don’t have turbo lag for the sudden acceleration and also due to the air tank for supplying mass flow-rate the vehicle can cross the shallow water and submerged.