Tikrit Journal of Engineering Sciences

A study of the critical speed of the vehicles on the wet roads has been done. And how it
is affected by the following parameters: wheel load , tire width, tire radius and water layer depth
and also the nature of the contact area of the tire (grooved or smooth).
It was found that the wheel load increase the critical speed positively while the tire
width, the tire radius and the water layer depth decreased the critical speed, It was also found
that grooves in the tire surface improve vehicle performance on wet roads .

ف The finite element method is used to investigate the ultimate bearing capacity
of two closely spaced strip footings on geogrid reinforced sand. The effect of variation of
several parameters on the bearing capacity had been studied (number of reinforcement layers,
optimum depth of the first and last layers of reinforcement). In this study the main results show
that, the bearing capacity of the soil increases, and settlement decrease as with the number of
reinforcement layers. The optimum depth of the first layer of reinforcement ranged between
(0.375-1)B, while optimum depth of the last layer of reinforcement varies between (1.125-
2.25)B depending on the angle of internal friction. The optimum number of reinforcement
layers is ranged between (4-6) depending on the center to center spacing between the interfering
footings and the angle of internal friction.

The main research objective is to study the hydrogen production and more particularly to
examine in details the effect of reaction conditions on the catalytic processing of methane
decomposition. The H2 production were conducted in a quartz tube fixed bed reactor over three
kinds of catalysts Fe/AC(Locally prepared), γ-Al2O3 and Activated Carbon(AC) (Commercial).
The Fe/AC catalyst were prepared by a precipitation method and characterized by BET. The
reactions were carried out under atmospheric pressure and at different temperature (800, 850,
and 900 OC) with different VHSV(Volumetric Hourly Space Velocity), the outlet sample were
measured using H2 Analyzer. The results exhibit that the highest H2 Production (26.3 %) was
obtained over local AC ,when the CH4 decomposition was (41.7%) at the following conditions:
temperature: 900°C ,VHSV 3.6 and 6.0 l/h g.

In the last few years wireless local area network (WLAN) technology and products have grown
unusually. This growth has encouraged many researchers to employ WLAN technology in different
application Areas. Recently, using IEEE 802.11 WLAN in industrial automation applications is attractive
and more interesting. However, the currently used medium access mechanism makes WLANs nondeterministic
and hence not suitable for industrial real-time traffic. Legacy IEEE 802.11 WLANs were
initially designed for best effort traffic only and did not provide any QoS support for this kind of traffic.
The new amendment IEEE 802.11e standard was introduced and ratified in 2005. It defines the concept of
a Hybrid Co-ordination Function (HCF) at the MAC layer for medium access control. HCF is a
combination of HCF Controlled Channel Access (HCCA) with parameterized quality of service (QoS)
and Enhanced Distribution Channel Access (EDCA) with prioritized QoS. Enhanced Distribution
Channel Access (EDCA) is an enhanced version of Distributed Coordination Function )DCF( mechanism
used in the original IEEE 802.11 WLAN. This paper analyze the performance of the EDCA in an
industrial automation network with real-time requirements by means of a simulation with the network
simulator OPNET 11.5 and compares the results with the DCF in terms of latency and throughput in
various scenarios.

This paper presents LQR and GA controllers which applied to control the speed of a DC
motor and to maintain the rotation of the motor shaft with particular step response. In
the state space, the control strategy is the states feedback and the most used techniques
are the LQR. Liner quadratic regulator (LQR) provides an optimal control law for a
linear system. It’s a control strategy based on minimizing a quadratic performance
index. In despite of the good results obtained from these method, the control design is
not a straight forward task due to the trial and error method involved in the definition of
weight matrices. In such cases, may be hard tuning the controller parameters in order to
obtain the optimal behavior of the system. In this work, it proposes a states feedback
technique in which there are no trial and error processes involved and the control design
is carried out to fulfill specifications, for minimize overshoot and minimize settling and
rising times. The proposed technique is based on the use a genetic algorithms. The
obtained results show that is possible to design controllers which fulfill design
specifications.

Although there are several techniques that have been used to differentiate between benign and
malignant breast tumor lately, support vector machines (SVMs) have been distinguished as one of
the common method of classification for many fields such as medical diagnostic, that it offers
many advantages with respect to previously proposed methods such as ANNs. One of them is that
SVM provide a higher accuracy, another advantage that SVM reduces the computational cost,
and it is already showed good result in this work.
In this paper, a Support Vector Machine for differentiation Breast tumor was presented to
recognize malignant or benign in mammograms. This work used 569 cases and they were
classified into two groups: malignant (+1) or benign (-1), then randomly selected some of these
samples for training model while others were used for test. The ratios were 84.4.0% of accepted
false, 947142% of refused false. These results indicate how much this method is successful.

The present work deals with studying the dynamic behaviour of continuous distillation tray
column and implementing different type of control strategies for the separation of binary
mixture composed of ethanol and water. Mathematical model of distillation column is derived
and designed by using Matlab program depending on the mathematical model derived to find
temperature response for many disturbances. The comparison between the experimental and
theoretical responses for temperature in top and bottom of distillation column for step change in
feed flow rate, reflux ratio and feed weight fraction showed that the difference is simple. This
study includes designing fuzzy logic controller which depending on some of logic rules
depending on fuzzy sets and through trading from experimental works where designing this
controller by using Matlab program and applying it on dynamics model for two control scheme
and tuning it by trial and error method. The Comparison between fuzzy logic and (PID) control
methods is done for many disturbances and measure the controller performance by using mean
square error and integral square error that the result performance showed that the fuzzy
controller better than the conventional controller through fast access to the desired value and
cancelling the disturbances.

Coagulation, flocculation and sedimentation are widely used in water treatment to obtain pure
drinking water. Thus, efforts have made to find alternatives to alum. In this study, Starch and
Dextrin have been chosen as natural coagulants. A set of experiments were carried out, conditions
were varied in (30-500 NTU), and (5-10) for the water turbidity and acidity pH ,respectively.
The results showed that Lamella has the ability to increase the efficiency of sedimentation process
in flocculation/settling tank due to reduction in surface loading and increasing in a retention time .It
has also been observed that the efficiency of Lamella was ranged in (50-40%)compared with a Jar
test that has efficiency between (60-50%).

In this research the characteristics of bed material of 35km of Tigris river from Badoosh to
the end of Mosul City was studied ,nine locations were selected for sampling surface and subsurface
material, at each location samples are collected from left and right bank of the river. Analysis of
these samples show that the gravel surface bed material of Tigris river had D50 equal to 33mm with
a dominant size very coarse and coarse gravel with a percentage 42%, 36% , respectively, sand is
almost mislaid in this layer. The particles of surface layer had a disc shape with a percentage 51%
and blade 19%, spherical 17%, and cylindrical 13%. The results show that the right bank particles
are coarser than left bank. The subsurface bed material consist of gravel and sand, the D50 of this
layer was equal to 17mm, the domain size was coarse gravel with a percentage 29% , sand
percentage in this layer was about 17%. The subsurface layer is unaffecting on any changes in flow
regime because it is completely protected by gravel surface layer. Comparison of obtained results
with previous results shows that there is no significant changes occurred in properties of the river
bed material except little changes in composition of surface layer especially in the fine material.The river under the current flow conditions with flow rate in around of 500m3/s will reserve to the
same bed material properties in the future.

The influence of the operating conditions on the losses rates in controlled batch
and continuous fermentation reactor has been studied. In which 120 l pilot fermenter
reactor used to produce acetic acid from ethanol at standard condition. The results show,
the increasing of 1 ºC of mixture temperature, increasing of 1 m3/h of the aeration flow
rate or increasing the mixing speed to 1 rpm leading to increase the losses rates to (1.22,
0.92, 0.94 ml/l) respectively.

The Traditional Neighborhood Unit represents one of The cultural state of the Society. It is
related to the environmental cases saving some chances, abilities, reducing power, controlling
atmosphere, and providing comfort since the building is one element of the ecological system
and not a different and an isolated from the surrounding ecological systems.
The problem of the current research is concentrated upon the lack of information on the
abilities of the traditional neibourhood which help her to stay up to now. So the aim of the
research is to find out the idea of ecological methodology. This has been accomplished through
some environmental and planning point of view. Also it depends mainly on signs of
accomplishing urban form concentrating on climatic attributes and environmental needs. This
paper hypothesizes that accomplishing the ecological methodology needs having tools and
means for the planning of the traditional neibourhood to control the climate challenges in cities
where we have hot and dry climate. To achieve such an aim here, an analytical and observative
approach together with an observation form have been adopted, to select such a sample is then
analyzed and the ecological features have been identified. Also, the abilities which give this
model planning resistance up to now have been found.

Thermosyphon is considered a heat transfer device in which its operating principle depends on the
evaporation and condensation of a working fluid which use the gravity forces to ensure the fluid
circulation. In the present paper, thermosyphon has been constructed to simulating the actual
applications to study the characteristics of heat transfer and its influence on the variation of cross
section shape. This paper, includes the procedure of a series experiments for three iron tubes in
vertical position with different cross section shape (square, rectangular and circular) having the
same hydraulic diameter and total length. Many factors have been investigate to distinguish their
effect on the heat transfer coefficient and temperature distribution on the surface. These variables
are: various cross section shape, heat input and coolant flow rate of the condenser, with the
methanol as working fluid of fixed rate at operating pressure which is near to the atmospheric
pressure. It has been demonstrated that from the total comparison of all shapes in the same
conditions, the performance of the square thermosyphon is higher than that of circular and
rectangular thermosyphon, respectively. Also, it has been found that the highest value of the heat
transfer coefficient at the square thermosyphon (1812W/m2oC) when it is compared with the
practical results of the other two types geometric shapes.