Engineering and Technology Journal

Zirconia fibers have been prepared by convertional method using cotton threads
impregrated in zirconium oxychloride solution ( ZrOCl2. 8H2O ). X-ray
diffraction shows the crystallinity of zirconia and optical microscopy shows the
fibers fabrication. Differnet percentage ( 2 ,4 ,8 , 10 and 12 ) of prepared zirconia
fibers mixed with ZnO powder.
All the specmen sintered at 1250 °C for 2hrs. Physical properties (density and
volume shrinkage) were measured and Mechanicl properties (Vicker ̉s
hardness,fracture strength and fracture toughness by indentation method ) were
calculated, 10% of fiber content has the maximum values for these properties for
the composite.

The microstructure and hardness of copper alloy after fatigue-creep interaction
testing have been investigated. Experiments were carried out in the temperature
range from room temperature to 300oC. Attention has been paid to the role of the
microstructure and hardness on the fatigue-creep strength of copper alloy. It has
been shown that, there is a little effect of microstructure in the cyclic response of
copper alloy, while the hardness has a significant effect on the fatigue-creep
strength. The relation between strength and hardness were described by the
following equation

The main portion of the paper is devoted for constructing approximated
solutions of linear integral equations with multiple time lags (IEMTL) using two
different types of basis functions B-spline functions and Orthogonal functions
containing (Laguerre and Hermite) with the aid of expansion methods (collocation
method, Partition method and Galerkin’s method). Algorithms with the aid of
Matlab language are derived for treating these equations using expansion methods.
Comparison between the exact and approximated results of these methods with the
aid of basis functions are given via two test examples and accurate results are
achieved.

Designs are generated in the Bezier curves at most contains gaps in form that is
drawn up in curve. This state is causing misshaping final form that depended on
curves generating.
In this research applies of suggested method is making Bezier curve generating
don't contains upon gaps and can controlled to eliminate gaps by using added
parameters to control it.
The research applies modified equations by using different shapes in different
cases and brought shapes (curves) don't contain the gaps and smoothing curves

Corrosion is the main problem for the embedded pipelines in different
environment resistivities. The most effective method to overcome this problem is
cathodic protection which represents as a control method of the pipe corrosion.
For achieving longer life of the external corrosion control system and evaluating
the performance of aluminum alloys which have been used as sacrificed anodes
to protect the embedded carbon steel pipe in different artificial simulated
resistivity of soils in Iraq of [5000 , 1000 , 600 , 50 and 25 (Ω.cm)]. Results show
that (Al-10 wt% Zn) as sacrificial anode alloy has the best anode capacity
compared with other anodes under these conditions (Al-5 wt% Zn), and (Al-15
wt% Zn). The selection for these alloys based on that they have high potential in
many environments when coupling with steels without effect of microbial,
obstacle and stray current. The polarization curves of alloys also show no
passivation behavior in artificial resistivities. The corrosion rate of different anode
alloys was determinated as a function of applied cathodic protection.
It was found a relationship between electric potential and time which
determine the optimum potential in different soil types for the three above selected
electrodes (anodes).

The effective removal of heavy metal ions from water is among the most
important issues for many industrialized countries. The present work has been
carried out to study the adsorption of cobalt [II] ion using activated carbon.
The removal of cobalt ions was investigated in batch conditions. The influence of
initial cobalt ion concentration, pH, adsorbent dose, adsorbent practical size;
contact time and shaking rate were studied at room temperature. The analysis of
residual Co [II] ions was determined using Atomic Absorption Spectrophotometer
GBC 933 plus. The results showed that the percentage adsorption of activated
carbon increases with time and that maximum adsorption was obtained within the
first 60 minutes of the process, and 300 rpm shaking rate.
The experiments showed that the maximum % adsorption of 100% was obtained
at adsorbent dose=0.4 gm, pH=13, particle size= (0-75) μm and 10 mg/L of initial
concentration of cobalt. These results indicate that activated carbon has potential
for removing cobalt ions from water

The test have been done on many samples of Hot Mix Asphalt using many types
fillers like Portland Cement, Limestone, Hydrated Lime as a filler, 1% Hydrated
Lime added to conventional mixture, Portland Cement introduced in cold state,
and passing sieve no.200 dust (conventional mixture).
In this research, Marshall test procedure is used to investigate the potential
prospects to enhance Hot Mix Asphalt properties. The objectives also include
determining which one of the additives is better than the others to be used and the
method of introducing this filler type to the mixture.
According to the results, we found out that the better filler affects the
mechanical properties of Hot Mix Asphalt is Portland cement when it introduced
with the aggregate at the mix temperature

Entropy generation in a vertical square channel packed with saturated porous
media, and subjected to differentially heated isothermal walls has been
numerically investigated.
The effect of Darcy, Reynolds, and Eckert numbers on Entropy generation was
studied. The entropy generation was found to be inversely proportional to both
Reynolds and Darcy number, while it was directly proportional with the Eckert
number.
It was shown that as Darcy and Reynolds numbers were increasing, the Bejan
number decreases, i.e., the irreversibility due fluid friction is dominated, while as
the Eckert increases, theirreversibility due to heat transfer increases

other applications, where high dynamic performance is required, this type of
controller usually needs costly speed sensor. Sensorless vector control is strongly
recommended in the dangerous sites and hostile environment, also to reduce cost
and increase reliability. In this way the rotor speed can be estimated from the
terminal voltage and current by means of DSP microprocessor. The DSP-estimator
is very complex hardware, has many operation problems, and very sensitive to the
electromagnetic interference (EMI). This paper proposes using the Artificial
Neural Network (ANN) to estimate the rotor speed, flux vector, torque, and unit
vectors instead of DSP-estimator. Also, the neural-based controller is proposed
too. The ordinary vector control with speed sensor and sensorless vector control
based on DSP-estimator PI-controller are represented in this work as point of
comparison. Also, the mathematical representation and simulation of the three
phase induction motor is illustrated in this paper. The proposed method, neuralbased
sensorless vector controller and estimator, gives superior performance in
different speed with respect to DSP-estimator PI-controller.

This research endeavors to create the 50Hz electromagnetic field atlas for
populated urban areas in the city of Baghdad (Iraq). For this purpose, the 3-
dimensions numerical model based on finite element method (FEM) with time
harmonic system is used for simulated and modeling electric and magnetic fields
surrounding the 132kV transmission system. The calculated magnetic and electric
field levels are compared to exposure guidelines given by International Commission
on Non-Ionizing Radiation Protection (ICNIRP). To assign the dangers regions in the
city, the properties of the Geographical Information System (GIS) were used. The
GIS map highlighted visually the unsafe zones and facilitate the extraction of the
electric and magnetic field levels of exposure.

Synthetic polymers such as polyurethane are used widely in the field of
biomedical applications such as implants or part of implant systems.
This work focuses on the preparation of base polymer matrix composite
materials by (Hand Lay-Up) method ,and studying the effect of selected weight
fractions (3 , 6 , 9 , 12 ,15) % wt of Calcium oxide (CaO) , Calcium carbonate
(CaCO3), Magnesium oxide (MgO) ,and Magnesium carbonate (MgCO3) particles
on some properties of the prepared composite.
Some mechanical tests were used to evaluate the prepared system (Tensile,
Compression, Impact, and Hardness) tests, and a physical test of (Water
absorption %), and all tests were accomplished at room temperature.
maximum results of tensile strength, compression strength, impact energy,
hardness, water absorption were ( (31 MPa),( 51 MPa),( o.265 J), (79.8 Shor (D)),
(0.229 %)) at using ( (9% wt (MgCO3)) , ( 9% wt of (MgCO3)) , ( 9% wt of
(CaCO3)) , ( 15% wt of (MgO)) , ( 15% wt of (MgCO3)) respectively.

In curved surface machining, parametric surface representation is normally used
for computer aided design (CAD). Parametric surfaces are often machined using a
flat end mill for roughing and ball end mill for finishing.
The core of this work is to propose and implement a model that is able to estimate
the cutting force in milling parametric surfaces with HSS ball end cutter of
different diameters. For this purpose, a mechanistic model has been developed to
calculate the cutting forces by dividing the cutting edge into small discrete
elements and applying simple mathematical expressions for the cutting force
estimation, once the force of each discrete element is calculated, these elements
summed up along the cutting edge to obtain the resulting cutting force. The slope
(inclination angle α) of the surface was included to the model to estimate the
influence of different conditions of the slope ( - 90o 〈 a 〈 +90o ) which most
parametric surfaces included. The results showed that the predicted results deviate
from experimental by (0.6-11 %) for Fx, by (2-10 %) for Fy and by (0.18-14 %)
for Fz

In this paper we introduce a new definition of a fuzzy normed space (to the best
of our knowledge) then the related concepts such as fuzzy continuous,
convergence of sequence of fuzzy points and Cauchy sequence of fuzzy points are
discussed in details.

Advanced numerical simulation program was used to analyze the performance of GaN
based vertical cavity surface emitting laser (VCSEL) with single, double and triple
quantum well(s) as active region. It was found that numbers of quantum well (QW)
variation inside the active region is the most critical factor on the VCSEL performance.
The lowest threshold current and highest in both the slope efficiency and differential
quantum efficiency were observed when the well number is double (DQWs) at 415
nm VCSEL. This is ascribed to that for single quantum well (SQW), some of the gain
begin to escape before lasing is achieved while for triple quantum wells (TQWs) while
are separated by many thick barriers, then transport carriers between wells will be
inefficient. As a result, a non-uniform carrier distribution may result

In this study, a low molecular weight epoxy resin diglycidyl ether of bisphenol
A (DGEBA) is cured isothermally with an aliphatic and aromatic amine hardeners
separately. (1) Triethylenetetramine (TETA), (2) diamino diphenylmethane
(DDM). The samples were prepared for different hardener/resin ratios, (under
stoichiometry, stoichiometry and above stoichimetry).
The mechanical Properties impact strength, tensile strength, hardness, flexural
strength, compression strength and bending strength of an epoxy system has been
investigated in this work. For DGEBA/TETA system the tests were done on four
hardener/resin ratios (10, 13, 15 and 20) phr and for DGEBA/DDM system the
hardener/resin ratios were four also; (24, 27, 30 and 34) phr. The results showed
that the above stoichiometry ratio formulation (15 phr for DGEBA/TETA system
and 30 phr for DGEBA/DDM system) gave the best mechanical properties, while
the DGEBA/DDM system showed better mechanical properties than the
DGEBA/TETA system

The main purpose of this work is to find the primary decomposition of the factor
group K (The factor group of all Z-valued class
functions module the group of Z-valued generalized characters for elementary Abelian
group G), where G is a finite Abelian group of type , p=5.
This work depends on finding the rational valued character matrix
from the character table of and finding the invariant factors of this matrix, also we
found the general solution of this decomposition and prove it by mathematical
induction. We have used the MATLAB program to calculate some results of this
work.

In this study, the effect of temperature, aspect ratio, number of layer and
boundary conditions on critical buckling load of composite laminated plate is
investigated experimentally and numerically. Simply-Simply-Free-Free and
Clamp-Clamp-Free-Free boundary conditions, three temperatures (40°C, 60°C and
80°C) and four aspect ratio (1, 1.3, 1.5 and 2) will consider for the experimental
work. The thickness of the plate was changed by increasing the number of layer.
It can be seen that when the temperature changes from 40°C to 80°C the
maximum value of Pcr is about (225 N/mm) at (T = 40°C, a/b = 2 and NL = 4), the
minimum value of Pcr is about (11.70 N/mm) at (T = 80°C, a/b = 1 and NL = 2).
Also, it can be shown that in the case of symmetric cross ply laminate (0o/90o/0o)
when the thermal load increased by about 100 % the buckling load decrease by
about 50 % at aspect ratio equal to 1. Finally, It is shown that the critical buckling
load increases with increasing the aspect ratio at constant temperature, number of
layers and boundary conditions

Where the native soils have poor structural qualities or are expansive, the soil
investigation report may recommend importation of soils better suited to providing a
subbase for structures. This requires considering two soil layers in bearing capacity
calculations.
Calculation of the ultimate bearing capacity of shallow footing on a two layered system
of soil depends on the pattern of the failure surface that develops below the footing. For a
weak clay layer overlaid by a top dense sand layer, previous studies assumed that the
failure surface is a punching shear failure through the upper sand layer and Prandtl's
failure mode in the bottom weak clay layer.
In this paper, the bearing capacity of subbase layer underneath by a soft clay layer is
investigated. The properties of the subbase material are measured in the laboratory.
Design charts were obtained which can be used to select the suitable thickness of the
subbase layer for a design allowable bearing capacity.

Since most of our industrial applications suffer from aging of units. and hence
the penalty of gaseous harmful releases with bad corrosive influences on airconditioning
components. However all the available solutions to diminish these
influences are related to painting parts of the air-conditioning system with different
substances and methods. The present study investigates the effect of chemical
painting on the performance of these air-conditioning units. This research is a
practical study which explores the influence of a specified kind of chemical
painting used to paint Aluminum fins and copper pipes in the refrigeration system
for window type air-conditioning units of (2tons capacity-reciprocating compressor
-R-22) on it’s performance through calculating each of the capacity of
refrigeration, compressor work, transmitted heat and coefficient of performance
before and after the chemical painting process, and making comparison between
the two in various operating conditions. It was found that the coating causes a
decrease of the capacity of refrigeration, compressor work, transmitted heat and
coefficient of performance. However it saves all parts in refrigeration system from
corrosion for along time. The practical part were conducted in the state company
for electrical industries

The aim of this work is to study the effect of the flow in the induction system on
the reciprocating air compressor performance. The study was carried out on the
reciprocating air compressor with two cylinders and three stages. The cooling
between two cylinders occurs by the air and used three pipes with different length
and diameter. A mathematical model is presented to calculate the pressure,
temperature, volume, mass and volumetric efficiency. This model depends on the
Runge-Kutla method to solve the differential equation system. The result show that
when used the multi – stage air compressor increases as result of efficiency air
cooling , the length and diameter of the induction pipe and velocity of compressor
have a significant influence on the compression wave capacity also the final
pressure generated in compression space which caused to increase the volumetric
efficiency .