Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 25, Issue 10

Volume 25, Issue 10, December 2007, Page 333-1193


A Study On The Effect of Using Various Reflectivities of Output Couplers on CW Carbon Dioxide Laser Performance

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 333-336

A practical study has been carried out on axial flow CW CO2 laser by
changing the output coupler with a wide range of reflectivities. ZnSe mirrors
were used in various reflectivities (20, 30, 40, 45, 50, 55, 60, 65, 70,75,80,85,90).
It has been found that the output power varies considerably with varies the
reflectivity of the output coupler. Thus the optimum reflectivity for 1m
optical length and 1cm discharge tube of CW CO2 laser is found to be 65±
5%. Our results have been compared with other published data.

Rapid Solidification Processing Of Al-3Wt%Mg Alloy

Talib Khalel Ibrahim; Ali Sabea Humod

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1102-1109

Metallic ribbons were formed under a chill block melt –spinning
process conditions for Al-3 wt% Mg alloy. X-ray diffractometry, optical
microscopy, electron microscopy and thermoanalytical data have been used to
establish comparison between as–received alloy and ribbons.
Thermogravimetric data showed that the weight gain is lower for the
ribbons compared to the as –received alloy.

Numerical Investigation intoVelocity and Temperature Fields Over Smooth and Rough Ducts for Several Types of Turbulators

Sabah Tarik Ahmed; Waheed S. Mohammed; Laith J.H

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1110-1127

Numerical study on a laminar and turbulent fluid flow and
temperature distribution in a rectangular duct with six types of vortex
generators has been carried out. A modified version of ESCEAT threedimension
code has been used to solve Navier-Stokes and energy equations.
The effect of vortex generator type, geometrical configuration, and
dimensions on flow and temperature in different planes has been presented.
The purpose of the present investigation is to highlight the complex threedimensional
interaction of the vortices generated by wings and other vortex
generators to understand how such vortices configurations structure the
velocity and temperature fields. Experiment in terms of velocities and
temperatures vectors and contours were performed on 6 configurations,
which experiments are (fin, fence, rib, wing-type, rectangular-type, and
winglet-type) vortex generators The results show good agreement with
published data.

Production of Organosilane by The Direct Reaction of Silicon with Methyl Chloride

Ihsan B. Hamawand; Fadi Z. Hanna; Moayed G. jalhoom

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1128-1142

The aim of this work is to study the production of organosilane by the
catalytic reaction of Methyl chloride (CH3Cl) with silicon (Si) and using copper
(Cu) as catalyst in a fluidized bed reactor. Gas chromatographic (GC) technique
was used on-line for analysis of the reacted gas.
The experimental work was carried out using columns with dimensions 5 cm
internal diameter and 50 cm height stainless steel used as a fluidized bed reactor.
Gas distributor was fitted at the bottom of column with 25 holes of 0.1cm hole
diameter.
The reaction started with experiments at different bed temperatures (200-
400) oC and the catalyst used is only copper (Cu) in two different percent (10 %
and 15 % of the silicon) in order to anticipate the optimum temperature and
catalyst value required for the best conversion of organosilane, these two
variables were kept constant for the remaining experiments.
Experiments were performed to reflect the effect of each of these variables:
particle diameter, bed height and reacted gas velocity on the organosilane
production. It was found that organosilane conversion was the highest at 350 oC
and 15% copper. The gas velocity at a value little more than minimum
fluidization velocity is gave better conversion than low velocity that gave fixed
bed or high velocity and that gave turbulent fluidization, higher level of contact
mass, and finally higher particle diameter this gives homogenous fluidization
concerning the reacted gas velocity.

Calculation of Energy Band gap of Porous Silicon Based On The Carrier Transport Mechanisms

Alwan M.Alwan

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1143-1148

The energy bandgap of photoluminescence porous silicon is calculated
based on the analysis of the current-voltage characteristics and the
measurements of the thermal activation energy of the zero bias and reverse
bias currents of PS/n-Si porous silicon diodes at different temperatures. The
2.1 eV bandgap resulting from these electrical measurements agrees well with
2 eV measured in PL spectra.

A Study On the Structure and Electrical Properties of Pbo.9Sn0.1Se/Si Heterojunction

Alwan M. Alwan

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1149-1153

In this work, as Study on the structural and electrical properties of
Pbo.9Sn0.1Se/Si hetrojunction was made by depositing compound of Lead, Tin
and Selenide film on Si by thermal evaporation.
XRD diffraction analysis of the film, shows the dominant crystal
orientation is (200) as well as (Pbo.9Sn0.1Se) film deposited is polycrystalline
structure.
Electrical properties of Pbo.9Sn0.1Se/Si heterojunction detector have been
investigated. The electrical properties under dark condition show a rectifying
behavior with low rectification factor, and exhibit soft breakdown reverse
current. C-V characteristics suggest that the fabricated diode was abrupt
type, built in potential determined by extrapolation from 1/C2-V curve to the
point (V=0) and it was equal to (0.4V).

The Biological Effects of Low Level Laser Therapy with Static Magnetic Field on Acute and Chronic Pain

Aseel A. Al-sharify

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1154-1161

This paper presents the biological effects of the low level laser therapy
(LLLT) with static magnetic field. The therapy was applied either alone or
combined with conventional therapy for the treatment of acute and chronic
pain. Two groups of volunteers with a variety of conditions were randomly
selected from the patients who were usually treated by conventional therapy.
The LLLT with static magnetic field was proposed to the first group as
extension of the conventional treatment. The second group underwent only
the LLLT with static magnetic field. LLLT was performed with an optical
and magnetic system specially designed for this purpose. Short–term and
long–term effects as well as conditions responding only to LLLT were
recorded. Results indicate disappearing or stable reduction of pain in most
cases, while partial restoration of mobility was noticed in some other cases.
The success of the treatment was up to 70% for both groups

A Content-Based Authentication Using Digital Speech Data

Hana; a M. Salman

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1162-1170

A watermarking technique for speech content and speaker authentication
scheme, which is based on using abstracts of speech features relevant to
semantic meaning and combined with an ID for the speaker is proposed in
this paper. The ID which represents the watermark for the speaker, is
embedded using spread spectrum technique while the extracted abstracts of
speech features are used to represent the watermark for the speech, embedded
in the original speech file using secret key. The abstracts speech feature is
implemented using B-spline curve interpolation. The paper provides a
background knowledge for the concept of speaker watermarking and contentfragile
watermarking based on digital speech data. Then, the suggested
feature based authentication scheme is developed and the results from the
evaluation are presented. Show that the suggested scheme is successful in
combining speech and speaker watermark authentication.

The Effect of Annealing Temperatures on Optical and Electrical Properties of PbTe Thin Films

Akram N . Al-Mashhadany; Noor S. Sadeq

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1171-1183

The study was carried out by the preparing of PbTe thin films and studying the
effect of annealing temperatures on electrical and optical properties.
The PbTe thin films have been prepared by thermal evaporation in a vacuum of
(2*10-5) Torr with thickness 500nm at room temperature and annealed at different
annealing temperatures of (373,423,473)K for 30 min.
The electrical measurements show that the PbTe thin films have two kinds of
activation energy which increases with increasing annealing temperature.
The Hall Effect measurements prove that thin films are n-type at room temperature
and convert to p-type by annealing temperature and it is found that
NH decreases with increasing annealing temperature but μH increases with increasing
annealing temperature.
The optical measurements show that the PbTe thin films have direct energy gap
which show that energy gap increases with increasing annealing temperatures and it
is found the transmittance increases with increasing annealing temperatures

Surface Preparation of Aluminum for Plating by Zincating

Mohammed Hliyil Hafiz; Baha Sami Mahdi

Engineering and Technology Journal, 2007, Volume 25, Issue 10, Pages 1184-1193

The objective of this work is to gain better understanding of the
influence of zincate bath chemistry on zincating morphology of Aluminum
bond pads to provide reference for zincating chemistry design and process
control for wafer bumping applications.