Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 26, Issue 2

Volume 26, Issue 2, February 2008, Page 37-277


Influence of Locally Produced Waterproofing Admixture (Sternson 300) on Concrete Absorption and Strength

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 49-61

In this work, the influence of waterproofing admixture of stearate type on the
water reduction of concrete mix (1:2:4) for a given workability, (50+5)mm slump was
investigated. Results indicated that this admixture has a little influence on the water
reduction of concrete. Therefore this admixture cannot be considered as a water
reducer since it does not conform with the requirements of type (A) admixture in
accordance with (ASTM-C494-98 Type A)[1].
The same influence on the compressive strength of concrete (fcu) at various ages
(7,28,60 and 90) days was studied. Results showed that the use of this admixture at
recommended dose specified by the manufacturer has no significant effect on the
compressive strength of concrete. On the other hand, overdoses of this admixture lead
to a considerable reduction in the compressive strength.
The efficiency of this admixture at different doses in reducing the total water
absorption of concrete and the absorption of water by the capillary action was also
examined. Results revealed that this admixture is not effective in reducing the water
absorption with all doses used in this work and at different ages compared with
reference mix without admixture.

A Study on Wear and Erosion-Corrosion Resistance of Two Typs of Cast Irons.

Sami.A.Ajeel; Safaa Mohammed Hasoni

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 111-123

The wear and erosion-corrosion resistance of gray and ductile cast irons
were studied for their important in most applications. The wear tests were carried
out using a pin-on-disc machine by applying different loads (10,20 and 30 N). The
wear rate was measured using weighting loss method.
Erosion-corrosion rate measurements for both types of cast iron in
(0.01%,0.58% and3.5%) NaCl solutions using a rotating disc of 450 rpm indicate
that erosion-corrosion resistance of ductile iron is better than that of gray cast iron.
Microstructure observations after erosion-corrosion indicate that it plays a
role in erosion-corrosion ; the predominant ductile matrix on the microstructure of
ductile iron is at lower erosion-corrosion rate than that of gray cast iron .
Localized attack usually has bright surfaces free from corrosion product. Pits are
often observed on the line flow direction on these materials. These pits have a
characteristic horse shoes shape for both types of cast irons. Optical microscope
examination for the specimens indicates the presence of white and dark areas
which refer to graphitization and pitting corrosion respectively. The wear rate is
influenced by the form of phases therefore the flake graphite form in gray acts
more like a lubricant film between two contact surfaces than spheriodal
graphite. Brinell hardness measurements for both materials show that gray iron has
higher hardness than ductile iron so that wear tests at different loads (10, 20 and 30
N) for both materials indicate that gray iron has high wear resistance than ductile
iron and the wear rate increases sharply after (20N) for ductile iron. These results
are related to high hardness and graphite phase form on the microstructure of gray
iron.

Vanadium Oxide Recovery from Spent Catalysts by ChemicaL Leaching

Falak.O.Abas

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 124-138

The Vanadium content of the catalyst can be reclaimed for further use. The
aim of present work is to recover Vanadium pentoxide (V2O5) from spent catalyst
which previously used by a local detergent factory using chemical treatment.
This type of treatment consist of chemical solution of sodium hydroxide
(NaOH 10–50 %) which is reacted with Vanadium in the spent catalyst to get
sodium vanadiate at temperature(80 ± 5Cº) for (2-10) hrs to get pure Vanadium
pentoxide .
Different extractive conditions were carried out for the same manufacturing
system above as chemical alkali solution of NaOH with in the range (10-50 wt.%)
,time of chemical treatment with in the range (2-8 hrs) ,and mixing velocity for
reaction solution with in the range (75-200 cycle/min) ,then a prepared products
will be optimized by the use of adsorption technique of vanadium on the surface of
active carbon particles (2 mm mesh size) ,where 45 gm of active carbon were
applied on packing column of 3 cm diameter and 300 cm long , then graph this
results in order to optimize the extractive condition above and the optimization
results are:
Pure vanadium pentoxide (85%,3.60 gm ) from spent catalysts result at
optimum conditions of 20 wt.% of NaOH alkali solution ,8 hrs time of mixing
reactants ,and 95 cycle/min mixing velocity (medium velocity to give homogeneity
of reaction) .

The Influence Of Bonding Mode and Wire Setting On The Stresses Of Metal Matrix Composite Reinforced with Continuous wire

Basim. Mohammed Fadhel

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 139-145

This paper deals with the influence of bonding mode and the setting of the
reinforcement between matrix and reinforcement for metal matrix composite on the
induced stresse and also on the value of the reinforcing A charpy specimen with
notch was used as a specimen test for comparison . Analytical model was built
via ANSYS 8.1 software with a nonlinear solution based on the elastic –plastic
behavior for both phases (matrix and reinforcement).Five miscellaneous cases for
bonding mode and the setting of the reinforcement (wire with 1 mm diameter)
were used .The results exhibit the eloquent perfect bonding on the value of
reinforcing and also the setting (semi-circle) of the reinforcement in the matrix
which gave the best reinforcing.

Effect of Coarse Aggregate Characteristics on Drying Shrinkage of Concrete

Tareq Salih Al-Attar

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 146-153

Concrete is a composite material, consisting, mainly, of three phases: coarse
aggregate, cement mortar, and the interface zone between them. The characteristics
of the interface zone largely govern the bond between cement paste or mortar and
aggregate. The restraining effect of aggregate to drying shrinkage strain depends
much on the bond between aggregate and cement paste.
In this paper, it is aimed to investigate the effect of coarse aggregate
characteristics, that affect bond strength, such as; type, shape, surface texture, and
moisture content, on drying shrinkage. Four types of coarse aggregate were used.
Three of them were normal-weight, while the fourth was a light-weight one. Each
type of coarse aggregate was used in two moisture conditions, dry and saturated.
The testing program extended to 150-days age and comprised; length change,
modulus of elasticity, compressive and splitting tensile strength of concrete.
It is concluded that using saturated coarse aggregate always yields higher
shrinkage strain than dry aggregate. The percentage increase seems to be affected
by the aggregate water absorption. At early ages, After 28 days, there is large
differences in relative shrinkage for different mixes. Later than 28 days, the
variation in ratios settled to approximately fixed values

Ductile and Gray Cast Irons Deterioration with Time in Various NaCl Salt Concentrations

Sami A. Ajeel; Safaa Mohommed Hasoni

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 154-168

Gray cast iron is used in wide engineering applications especially pipes
and these pipes are exposed to failure in most cases so that ductile cast iron is used
instead of it later.
This project deals with the study of microstructure characteristics and
chemical analysis for both materials in order to use them in the analysis of the
microstructure after the corrosion tests involving immersion, polarization in
different sodium chloride concentrations (0.01%, 0.58% and 3.5% NaCl).
Immersion results indicate that the corrosion resistance of both types of
cast irons is excellent and ductile iron is better than gray cast iron and the
reduction in corrosion rates for both materials is related to barrier layer deposited
on the surface which is more uniform on ductile iron surface.
The electrochemical tests involve measurement of corrosion potential in
open circuit using the same solutions for both materials and potentiostatic test is
used to measure cathodic and anodic polarization in the above solutions. The test
started from cathodic region to the anodic region with sweep rate of 10 m V/min to
obtain the general behavior and measure the polarization parameters for both
materials.
The measured corrosion potentials of the open circuit in all solutions are
more noble values for gray iron than that for ductile iron. Corrosion potentials on
polarization measurements point out to the same indication but the ability to
start and form barrier layer in ductile is better than in gray iron.
Microstructure observations after the electrochemical tests indicate
the presence of uniform layer on ductile surface and graphitization process is
obtained on gray iron.

Stress Evaluation of Low Pressure Steam Turbine Rotor bBlade and Design of Reduced Stress Blade

Arkan K. Husain Al-Taie

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 169-179

The low pressure steam turbine blade rows have a history of stress failure . They suffer from
tensile and bending stresses partly due to the centrifugal force as a result of high rotational
speeds and partly due to high pressure, temperature and speed steam loading. The centrifugal
force is one of the problems that face the designers of turbine blades especially the long ones.
The designer always aims at reducing these stresses. One way to do so is by the reduction of blade
mass. That is to make the blade of variable cross section stead in of straight. This paper presents
the method of reducing cross section. Analysis of such blade is also done as applied to the (P 23-
14A) steam blade.

Automated Electronic Circuit Design for Low Pass Filter Based on Genetic Algorithm

Hanan. A. R. Akkar; Mohammed. K. Abrahem

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 180-188

In this paper a proposed method to design electronic circuits by using software approach based on
genetic algorithms is presented. The method is implemented to design low pass filter with a
minimal knowledge about the design (the response of the filter and cutoff frequency).
Butterworth filter type is chosen because of its smooth response. This method provides
impressive results and the circuits obtained provide higher efficiency than the circuits which
might be designed by the expert engineer. This method allows the topology, the component
values, and the number of the component of the circuit to be evolved by using genetic algorithms
(GAs) without human interference. Therefore, the proposed method can be expandied to be used
with any analog (passive or active) circuit by making a few changes in the program steps (i.e. by
changing the fitness function and improving the simulation of the circuits). MATLAB (Ver. 7)
language is used in programming the genetic algorithm. The circuits created by genetic
algorithms are built using EWB program to make sure that the obtained results are true and
accurate.

Numerical Simulation of Solidification Around Staggered Tube Arrangement With Convection – Dominated

Waheed S . Mohammed; Zainab H. Hassan

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 189-201

This work describes and analyses thermal storage system as a phase change problem which
involves a fluid flowing inside cooled tubes in a staggered arrangement installed in a rectangular
duct surrounded by a phase - change material (water).
The temperature of the fluid inside the tubes is below the freezing temperature of the PCM which
causes ice formation around each tubes. The problem is modeled as, two- dimensional, time
dependent and convection–dominated phenomena .A finite volume numerical approach is
developed and used to simulate the physical details of the problem .This approach is based on the
enthalpy method which is traditionally used to track the motion of the liquid – solid front and
obtain the temperature and velocity profiles in the liquid –phase. The study gives an instruction on
the presentation of ice – on – coil storage tank. Results of solidification experiments are used to
assess and evaluate the performance.

Modelling The Behaviour Of Sand Under Strain-Controlled Loading BY The Finite Element Method

Omar al-Farouk S. al-Damluji; Mohammed Yousif Fattah

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 202-227

Strain-controlled tests are conventional in soil mechanics laboratories. It is
intended in this paper to simulate both triaxial and simple shear tests
theoretically by using the finite element method. The solution of the nonlinear
equations is obtained by several iterations. The Newton-Raphson with
tangent stiffness method in which the stiffness matrices are tangents is
adopted. The model used in this paper is the ALTERNAT model which
forms the major component of a double hardening model for the mechanical
behaviour of sand under alternating loading.
The finite element method is used in simulating the behaviour of round
uniform quartz sand under monotonic drained loading with constant mean
stress and cyclic constant volume loading (undrained). The monotonic test
was conducted with constant mean stress, where the specimen was
compressed in one direction and extended in other directions while the mean
stress (the average of the principal stresses) is kept constant and equal to 137
kPa. It is noticed that the peak stress is occurring at very small strain
(0.122). The stress-strain behaviour may be attributed to the particle
roundness and grain size uniformity.
In the cyclic tests, the specimen is sheared by cycling the shear strain while
the volume was kept constant. By doing this, an undrained strain-controlled
cyclic test similar to that typically done in many laboratories is numerically
simulated.
It was found that the mean stress during shearing is higher than the initial
consolidation pressure. This implies that only negative pore pressures occur
in the first two cycles. A careful study shows that there exists an effective
stress ratio line or zero-dilatancy line in both compression and extension
regions, beyond which the specimen dilates.

Content-Based Authentication Using Digital Speech Data

Hana; a M. Salman

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 228-239

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 represents the
watermark for the speech, is 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 content-fragile watermarking based on digital speech data. Then, the suggested
feature based authentication scheme is develop and the results from the evaluation
are presented. It shows that the suggested scheme is successful for combining
speech and speaker watermark authentication.

Optimization of Production of Food Grade Gelatin from Bovine Hide Wastes

Mahmood M. Barbooti; Shahrazad R. Raouf; Firas H. K. Al-Hamdan

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 240-253

The optimum conditions for the production of food grade gelatin from the tannery
bovine hide wastes are established. The process involves cutting the hide wastes into
small pieces (1-2 cm2), and washing them with water to remove the dirt. The washed
pieces are placed in the liming tank containing 10% of lime in water with stirring for
five weeks. After washing with water to remove the lime, the collagen is neutralized
to pH 7 with hydrochloric acid. The extraction is carried out in four stages using hot
water. The gelatin extracts are filtered, subjected to deionization and concentrated
with vacuum evaporator up to 20-35 wt%. The gelatin is then dried by two types of
dryers (tray dryer and spray dryer).
Box-Wilson method is adopted to obtain a relationship between the three variables
(temperature, time and pH) and gelatin yield in the first stage of extraction and two
variables (temperature and time) and the gelatin yield in the other third stages of
extraction process. The experimental data were fitted to second order polynomial
models for all stages.
The most favorable operating conditions for the extraction of gelatin are: -
The First Stage: Temperature = 64 oC , Time = 5 hr , pH = 7
The Second Stage: Temperature = 74 oC , Time = 3.72 hr , pH = 7
The third Stage: Temperature = 84 oC , Time = 3.69 hr , pH = 7
The fourth Stage: Temperature = 98 oC , Time = 3.83 hr , pH = 7
The overall yield of gelatin is 55%, under the previous condition. The quality of
gelatin was checked against food grade specification at the Nutrition Research
Institute of the Ministry of Health. The results are acceptable within the boundaries of
the desired properties.

Mechanical Properties of Composite Material Using Natural Rubber with Epoxy Resin

Hani Aziz Ameen

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 254-264

In this paper the mechanical properties of three types of composite materials using
natural rubber vulcanized, unvulcanized and reinforced rubber have been
investigated . The composite material using natural rubber and epoxy resin is
manufactured by three methods, first method is mixing the natural rubber with
epoxy resin by special mixer without any additional materials, the second method
is to make a layer of rubber then coating it with a layer of epoxy resin and bonding
using the rolling process. The third one is use in the natural rubber as a matrix
material and using additional materials like carbon black in specific ratio and mix
with them the epoxy resin in five ratios ( 20%, 40%, 60%, 80%, and 100%) .
The first and second methods failed because composite material produced was
inhomogeneous while the third method succeeded and the composite material was
homogenous. Compression and hardness tests have been done on the resulting
composite material of the third method and from the result it is found that the
composite material has good properties and these properties improved by
increasing the ratio of epoxy resin to the natural rubber. Then the mechanical
properties of three types of composite material using natural rubber vulcanized,
unvulcanized and reinforced rubber have been investigated . Each type was coated
with six percentages of epoxy resin (0% , 20% , 40%, 60%, 80%, and 100 %) . The
values of Young’s modulus, yield stress, tensile strength and yield strain which
were calculated for each case and for all percentages of epoxy resin. It is concluded
that the properties of the new composite material using natural rubber is
muchbetter than the properties of the pure natural rubber and the increasing in the
percentage of epoxy resin in vulcanized rubber leads to a decrease in Young’s
modulus and increasing percentage of epoxy resin in unvulcanized rubber and
reinforced rubber leads to an increase in Young modulus

Indirect Field Orientation Control of Induction Machine with Detuning Effect

Rami A. Mahir; Ziad M. Ahmed; Amjad J. H

Engineering and Technology Journal, 2008, Volume 26, Issue 2, Pages 265-277

Field orientation control (FOC) methods of an induction machine achieve
decoupled torque and flux dynamics leading to independent control of torque and
flux as for separately excited DC motor, but they are sensitive to motor parameter
variations. The has present work selects the indirect field orientation control
(IFOC) as an effective method for eliminating the coupling effect. The results
show how well the drive performance has been improved by this control strategy.
However, to which extent the control strategy can perform the decoupling relies on
the accuracy of the slip frequency calculation. Unfortunately, the slip frequency
depends on the rotor time constant that varies continuously according to the
operational conditions and, then, the coupling effect may again arise.
This paper investigates the improvement in the performance of the
induction machine dynamics as the IFOC technique is utilized, also, it
investigatesthe degradation in dynamic performance when the rotor resistance is
deviated from its nominal value.