Engineering and Technology Journal

Fatigue damage accumulation behavior of 2024 Al-alloy has been investigated
under the effect of varying the time of shot peening. Damage accumulation
from low-high and from high- low stresses has been studied using rotating
bending tests. The time of shoot peening is in the range 2-20 min. The
conclusions derived from this study are:
1. The number of cycles to failure increases as the shot peening time increases
up to about (6-8) min. after that the number of cycles decreases.
2. Surface roughness (Ra) is approximately proportional to the time duration
of shot peening

In this study, results of an analysis for the MQW semiconductor laser
performance are presented. This analysis considers the steady-state condition
and small signal modeling to introduce optical gain, charge carrier density,
current and output laser power. Accordingly, a description of AC RLC circuit
equivalent to semiconductor laser structure is presented in order to introduce
operation and output parameters as well as achievable efficiencies.

The present work performs mechanical buckling analyses on square
and rectangular plates with central cutouts under uniaxial compressive load.
The cutouts were either circular or square holes. The material of plates was
the widely used in aircraft structures i.e. Al-2024 T3 aluminum alloy. The
finite element structure analysis technique was used to study the effects of
plate support conditions, plate aspect ratio , hole geometry, and hole shape on
the buckling characteristics of the perforated plates. The well- known finite
element structural ANSYS program was used to perform the calculations.
Square plates with circular and square cutouts showed decays in buckling
strengths as the hole sizes were increased. On the other hand , rectangular
plates unexpectedly exhibited an anomalous behavior when their buckling
strengths enhanced as the holes were enlarged. The plate buckling mode
shape could be symmetrical or anti-symmetrical, depending on the plate
boundary conditions, aspect ratio and the hole size. For the same cutouts

This research deals with the study of the effect of adding pure
aluminum powder of different sizes (106μm, 250μm,1-2mm)to
novolac materials. This has been achieved by hot pressing matrix
and reinforcement materials, after preparing the matrix from
novolac (85%of phenol formaldhyd and 15%of hexamethylin
tetra amin as hardener with the assistance of an acid).After
sieving the matrix to the required particles size , a compression
pressure (15Mpa) has been applied for 30 minutes as forming
time, and under different forming temperature degrees ranging
from75,100,125,150,200co. So their influence on the matrix
characteristics and the compound material is studied.The results
have shown that the addition of particles to the matrix improves
to a great extent the mechanical properties, since testing
deflection and hardness have shown an increase in direct
proportion to increase in the grain size of the additive particles,
which work as nucleas to increase the cross linking of the
matrix.The tests show the best forming temperature is 150co
which gives best properties

This research aims to study the role of soil suction and clay minerals
on volumetric changes of a collapsible soil selected from Hawy Al-Kanissa
area in Mosul city. The effect of low and highly plastic clayey soil as an
additive to this soil has been investigated. The main results show the optimum
clay content for soil to collapse decreases with the increase in the plasticity of
soil. Swelling percent and pressure increase with the clay content, plasticity of
soil and dry unit weight.
Soil suction was also studied for collapsible soil with different clay
contents. The results show linear relationships for all types of soil. Soil suction
also increases with plasticity. Thus soil (CH) gave more suction than soil (CL).
However, dry unit weight had little effect on soil suction, which was frequently
negligible. Addition to that, statistical models between soil suction with
collapse and swelling potential were obtained with an acceptable correlation
coefficient

Hospital solid waste management is one of the most
neglected parts of the managerial process in Baghdad. This
research has been done to evaluate the actual state of this system in
some hospitals in Baghdad as a case study and to find out the

In this paper a new family of transformation for image denoising is
presented, Multiridgelet and Walidlet transforms, which have been proposed
as alternatives to Discrete Wavelet and Multiwavelet transforms.
Walidlet transform is an intelligent tool for solving image processing
problems such as image denoising with straight edges, the general algorithm
of image denoising using discrete multiwavelet transform is introduced, then
followed by the general algorithm of image denoising using Walidlet
transform that is proposed here in order to achieve better results than that for
Walidlet thresholding, finally, a comparative study is presented to show the
differences between a mentioned algorithms

In this work, the single beam scanning technique was employed to express
the nonlinear interaction between laser radiation and semiconductor material
(lead sulfide) as well as to determine the thermooptic coefficient of the
material (lead sulfide). Direct measurement, low cost and reliability are the
main features of this technique. The value of the thermooptic coefficient was
determined to be -5.8x10-5K-1 for PbS thin film. Due to authors review, this is
the first attempt in Iraq to measure such parameter in semiconductor thin
films.

Electrical properties of p-PbSe/p-Si heterojunction detector have been
investigated. The electrical properties under dark condition show a rectifying
behaviour with low rectification factor, and exhibits 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 (0.49V).
Results of I-V characteristics under illumination conditions with reverse
bias voltage exhibit linear behavior with no saturation limit

The optoelectronic properties of (Al/c-Si) and sandwich structure type
(Al/PS/c-Si/Al) were reported. The nanostructure porous silicon is obtained by
photochemical etching without applying electric field. The photosensitivity of
(Al/PS/c-Si/Al) structure is determined by porous layer photoconduction.
Maximum spectral sensitivity of the porous layer is changed from (575-
610)nm depending on preparation condition.