Earticle

An ad hoc wireless network consists of a set of hosts (mobile nodes) which are connected together by wireless links. The nodes can communicate with each other using different routing protocols. The routing protocols perform well when the nodes are stationary but degrade drastically when the nodes are mobile. A variety of routing protocols have been proposed for ad hoc networks in the past. Based on update mechanisms, they are classified into reactive, proactive and hybrid routing protocols. The performance of these protocols varies depending on the simulation environment. Many researchers have been working in this direction to evaluate the performance of these protocols in different simulation environments. The simulations can be done on Qualnet, NS2, and Omnet++ etc. The main aim of this project is to explore this fact and compare the performance of three different protocols- AODV, STAR and ZRP which constitutes a good combination of on-demand (reactive), table-driven (proactive) and hybrid protocols respectively. It is taken into account that these protocols are the best protocols in their respective domains due to their low overhead. The performance of these protocols will be analyzed by keeping the nodes static, dynamic and then semi dynamic. The pause time of each node is varied so as to depict a real world scenario in case of semi dynamic. The evaluation is done by considering the performance metrics - throughput, jitter, average end to end delay and packet delivery ratio. The simulator used is Qualnet 7.1.

Increase in air humidity leads to discomfort and can cause health problems. Nowadays, traditional vapour compression air conditioning systems are widely used to decrease the moisture content of the air, but they result in high electricity bills. Recent studies show that use of absorbent material in the conventional systems can reduce electrical energy consumption. The desiccant systems are reasonably-priced, produce no CFCs, and capable of both drying and filtering the air. They provide an opportunity to control humidity and temperature independently, and have the capability of using low quality thermal energy. The aim of this study is to determine the performance of a Solar Desiccant Cooling System by TRNSYS in warm and humid climatic zone of IRAN. This paper computed the performance of a simple desiccant evaporative cooling cycle in four selected cities in Warm and Humid climatic zone of IRAN (i.e. Kish, Bandarabbas, Bushehr and Gheshm). The coefficient of performance (COP) has been computed for each location and compared. The results show that for Kish, this system shows high potential for comfort cooling in buildings compared to other locations in the same climatic zone.

An induction plasma generator is very attractive for several industrial applications especially in material processing, so a high-frequency power supply class-E inverter is required to generate the magnetic field at frequency ranging from hundreds of kilohertz to tens of megahertz offer high efficiencies at high power densities. A resonant inverter based on zero voltage switching and an adaptive control via a backstepping based on Lyapunov theory and tuning functions control is used as a power supply for inductively Plasma generator. A second technique is applied as a linear quadratic regulator is used as a power supply for plasma generator. This type of control does not only keep the output current and the voltage in phase but also makes the system operating in zero-voltage-switching mode for constant and variable load. On the strategy design of the gains which are determined by minimizing a cost function which reduces the tracking error and the control signal. A recursive least squares (RLS) estimator identifies the plant parameters at different load conditions. The evaluation of the state variables is obtained by estimation using Kalman Filter. Simulation results verified that the proposed strategy has good performance to variable loads providing fast transient response.

In this paperwe have considered an integro-differential equation which describes the charged particle motion for certain configurations of oscillating magnetic fields. This equation contains variable coefficients with large expressions which complicate the application of any numerical method. We have used variational iteration method to find its numerical solution by developing MATHEMATICA modulae and solved a number of numerical examples. The results show high accuracy and efficiency ofour approach.

Nowadays thin-film solar cells are increasingly used mainly because of their low cost. In recent decades the performance of these cells were significantly improved. In this work, we simulated a solar cell type GaAs using software (PC1D) to analyze certain parameters, in particular the properties of the window layer, base, emitter and BSF layer (thickness, doping ...), these parameters play a crucial role in the performance of the cell, and to optimize them, we studied their influence on the photovoltaic solar cell sizes. In order to highlight the importance of depositing a layer window type Ga 1-x Al x on GaAs solar cells, a comparison between two cells, one with no window layer, the other with a layer window, was made. The energy efficiency is increased from 24.9 registered in a cell% to 26.7% for GaAs cell Ga1-x Al x As / GaAs.

The ultrasonic velocity (U), density (ρ) and viscosity (η) have been measured for the binary mixture of 1-Bromopropane with Chlorobenzene at 303.15, 308.15, 313.15 and 318.15 K at frequency 2 MHz. From the experimental data acoustical parameters such as adiabatic compressibility (βad), intermolecular free length (Lf), acoustic impedance (Z), molar volume (Vm), free volume (Vf), available volume (Va), relaxation time (τ), internal pressure (πi) and Gibbs’s free energy (ΔG*) have been computed. These results are interpreted in terms of molecular interaction between the components of the mixtures.