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Iraqi Journal of Applied Physics

المجلة العراقية للفيزياء التطبيقية

ISSN: 18132065 23091673
Publisher: iraqi society for alternative and renewable energy sources and techniques
Faculty:
Language: English

This journal is Open Access

About

The Iraqi Journal of Applied Physics (IJAP) is a peer reviewed journal of high quality devoted to the publication of original research papers from applied physics and their broad range of applications. IJAP publishes quality original research papers, comprehensive review articles, survey articles, book reviews, dissertation abstracts in physics and its applications in the broadest sense. It is intended that the journal may act as an interdisciplinary forum for Physics and its applications. Innovative applications and material that brings together diverse areas of Physics are particularly welcome. Review articles in selected areas are published from time to time. It aims to disseminate knowledge; provide a learned reference in the field; and establish channels of communication between academic and research experts, policy makers and executives in industry, commerce and investment institutions. IJAP is a quarterly specialized periodical dedicated to publishing original papers, letters and reviews in: Applied & Nonlinear Optics, Applied Mechanics & Thermodynamics, Digital & Optical Communications, Electronic Materials & Devices, Laser Physics & Applications, Plasma Physics & Applications, Quantum Physics & Spectroscopy, Semiconductors & Optoelectronics, Solid State Physics & Applications, Alternative and Renewable Energy, Computers Networks and Applications.

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Contact info

P. O. Box 55259,
Baghdad 12001,
Iraq
Website: www.iraqiphysicsjournal.com
Email: admin@iraqiphysicsjournal.com
Email: editor_ijap@yahoo.co.uk

Table of content: 2012 volume:8 issue:1

Article
Laser-Based Measurements in Non-Equilibrium Plasmas

Authors: E. bin Selima --- R. Fortier --- A. Elmahdi
Pages: 3-10
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Abstract

In this article, advanced laser diagnostics have been used in combination with modeling to study fundamental non-equilibrium low temperature Plasma Assisted Combustion kinetics. We also discuss recent advances in ultra-high frame rate imaging, which provides new capability for capturing the dynamic evolution of high speed, unsteady flow fields, and/or increasing the data collection rate in short run time “impulse” facilities.


Article
Analytical and Experimental Study on Bound and Free Surface Waves in Wind-Wave Tank System

Authors: K.S. Jameel --- G. Ibeshiyv --- P.J. Vodesko --- L.K. Parshieva
Pages: 11-18
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Abstract

Microwave and acoustic systems operated in the large wind-wave tank show that most small-scale waves produced at large angles to the wind are products of breaking events bound to longer waves in the tank. These longer waves propagate at the dominant wave phase speed for fetches near 7m but travel at speeds corresponding to the phase speed of a wave half as long as the dominant wave at fetches near 26m. The microwave and acoustic systems operated at both 8mm and 2cm wavelengths. Measurements were made at seven wind speeds, five incidence angles, seven azimuth angles, and two nominal fetches. Two peaks were found in either the microwave or acoustic Doppler spectrum when looking upwind or downwind, but never in both. The sum of these spectral densities, the total short wave spectral density, was similar to, but lower than, previous measurements. The nature of millimeter-length bound waves was found to be different at long fetch than at short fetches, a feature not observed in centimeter-length bound waves.


Article
Measurement of Water Vapour and Temperature Profiles Within the Troposphere Using Ultraviolet Raman LIDAR System

Authors: R. Chandrakar --- S. Patel --- M. Kabral --- S. Agrawal
Pages: 19-26
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Abstract

In this work, developing a UV Raman LIDAR system to be used for measuring water vapour and temperature profiles within the troposphere. LIDAR provides a continuous remote sensing method for the simultaneous measurement of temperature and humidity profiles in the troposphere. This enables continuous monitoring of the radio refractivity profile with good time and height resolution, which is of great benefit in radiowave propagation studies. The system is designed to be used by day and night. The main benefit of this technique over the more traditional use of radiosonde ascents is in being able to continuously monitor atmospheric conditions, a capability of great benefit in the modelling of radiowave propagation.


Article
A Balanced Backoff Algorithm for IEEE802.11 Wireless Network

Authors: D.J. Kadhim --- S.H. Abdulhussain --- B.M. Ridha --- A.M. Abbas
Pages: 27-33
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Abstract

The Backoff mechanism is a basic part of a Media Access Control (MAC) protocol which provides addressing and channel access control mechanisms that make it possible for several terminals or network nodes to communicate within a multi-point network. Since only one transmitting node uses the channel at any given time, the MAC protocol must suspend other nodes while the media is busy. In order to decide the length of node suspension, a backoff mechanism is installed in the MAC protocol. The choice of backoff mechanism should consider generating backoff timers time, which is uniformly selected from the Contention Window (CW) and allow adequate time for current transmissions to finish and, at the same time, avoid unneeded idle time that leads to redundant delay in the network. Moreover, the backoff mechanism used should decide the suitable action to be taken in case of repeated failures of a node to attain the media. Further, the mechanism decides the action needed after a successful transmission since this action affects the next time backoff is needed [2]. Several back-off schemes will be discussed and a new proposed algorithm has been proposed to achieve high throughput of the IEEE 802.11 DCF.

Keywords

IEEE 802.11 --- DCF --- MAC --- Backoff Algorithm


Article
Temperature Dependencies of Refractive Index and Optical Elasticity Coefficient on Lens Induced in Nd:YAG Crystal

Authors: O.A. Hammadi --- M.S. Edan
Pages: 35-41
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Abstract

In this work, one effect of the optical pumping power on the characteristics of a solid-state Nd:YAG laser was studied. The main parameter considered is the change in focal length of lens induced in the Nd:YAG crystal due to temperature-dependent variation in both refractive index and optical elasticity coefficient. The pumping-induced change in focal length of such lens is an important parameter in laser design as it determines how long the optical resonator may keep its stability during operation. It also assigns the main features to be considered in order to obtain the optimum characteristics of the produced laser beam. This investigation does not consider all aspects may affect laser operation but it represents a forward step to understand the intracavity limitations of solid-state, specially Nd:YAG, laser.


Article
Characteristics of Gold and Silver Nanoparticles Deposited on Crystalline and Amorphous TiO2 Films by Femtosecond Laser Pulses

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Abstract

In the present work we report the effect of enhanced luminescence of gold and silver nanoparticles photodeposited on crystalline and amorphous films of TiO2. Such a system has two main characteristic features. The average distance between metal nanoparticles is of order of several nm. Metal nanoparticles size is less than (or of order of) 10nm. Absorption spectra of the mesoporous films additionally show that most of metal nanoparticles have approximately spherical shape.

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