Al-Qadisiyah Journal for Engineering Sciences

This work is devoted toward optimization of the parameters of the friction stir processing (FSP) which effect
on tensile strength of aluminium alloy AA6061-T6 of 6mm thick plate by applying a certain number of tests
utilizing the Taguchi method. Design of experiment (DOE) has been applied for the determination of the
most important parameters influencing ultimate tensile strength. FSP was achieved under three different
rotation speeds (800,1000 and 1250) rpm, different transverse speeds (16,25 and 32) mm\\min, and number
passes(1,2 and 3) in the same direction and tool tilt angle was 2° with using threaded cylindrical pin profile.
The best FSP parameters were 1250 rpm and 32 mm\\min and two passes. It was found that the higher
hardness value was 75HV in stir zone center and then decreases toward the TMAZ, HAZ and the base metal.

Castellated steel beams are section steel members with hexagonal or octagonal web openings which they
are made from standard hot rolled steel section I or H. The main advantage of these members is their
economic material. An additional important advantage is a possibility to guide service ducts through the
openings. The presence of the web openings influences the members’ failure behavior around the
openings, new local failure modes will come into existence, such as the buckling of the web post between
the openings, or yielding around the openings. Castellated beams with octagonal openings usually fail due
to web post-buckling because of the increase in depth. The current study focused on improving the
behavior of the castellated beam with octagonal openings using steel ring stiffener and adjusting the best
dimension and distribution for the stiffeners. All the models of specimens have been fabricated from a
parent I section (IPE 140). The models have been modeled and analyzed using finite element software
ANSYS (version 15). The analysis results showed that reinforcing octagonal castellated beams by adding
steel ring stiffeners around octagonal web opening was very active way to increase the ultimate load for
long span, where the ultimate load of reinforced octagonal castellated beam increased up to (286%)
compared with parent I-section beam. Economically, the percentage of additional steel material which
used to expansion and reinforce the castellated beams (spacer plate and steel ring stiffeners) was (36%)
when compared with the weight of parent I-section beam. While the allowable load at deflection (L/180)
was (260 %) compared to the allowable load of parent section at the same deflection. The gained benefit
was increasing the ultimate and allowable load of reinforced octagonal castellated beams by (186%) and
(160%) respectively by using additional steel material only (36%) from the weight of parent I- section,
which the additional steel material consisted from the spacer plates and steel rings. Also, the results
indicate that the best dimensions for the ring were when thickness equal to the web thickness of the parent
section and the width equal to the half of the parent section flange width

AC-drive systems based Permanent Magnet Synchronous Motor (PMSM) are widely utilized in industrial
applications due to many advantages including excellent efficiency, best reliability, and low-effective cost
compared with DC-drive systems. Design and implementation of an RLC compensator for a PMSM-drive
system is demonstrated in this paper. The main aims of using an RLC compensator are decreasing of TotalHarmonics-Distortion (THD) of the input line current and Ripple Factor (RF) of the electromagnetic torque
over a wide range variation in rotor speed and load. The entire transfer function of the proposed system is
derived for stability verification under the change of rotor speeds. The proposed PMSM-drive system is
implemented with and without RLC compensator for two cases; which are at a fixed load and a step-change
in load. Good performance is achieved using the proposed RLC compensator; in terms of THD and RF are
0.77% and 3.13%, respectively.

In wireless communication systems, the channel estimation problem has been played an essential challenge
to accurately retrieve the channel state information (CSI) such that reliable communication & wide coverage
can be provided. Due to the improvement and rapid growth of communication systems and in order to
maintain a reliable data transmission, estimation of CSI has become necessary. This in turn results, precise
receiver demodulation, accurate decoding, and equalization processes. This paper gives a survey on a fading
phenomena and a comprehensive review of the recent works that have already been done and studied related
to the problem of estimating channel parameters in wireless communication systems. Varieties of best
channel estimation techniques that have been recently evolved are explored. Comparison between them in
terms of computational cost, simplicity and appropriateness conditions is also discussed. This paper also
provides a basic introduction of wireless channel model, SIMO and MIMO channel

Sewage water treatment before disposing of it in surface water is one of the most important steps in reducing
pollution in these waters, which requires a high-capacity treatment plant for this purpose. Al Kufa city is
one of the important cities in Iraq. The city faced a rapid growth of population. This situation creates big
environmental complications and hazards. One of the biggest pollution issues in the city is the lack of
modern and efficient Waste Water Treatment Plant (WWTP). The aim of this study is to find a suitable site
for wastewater plant in Al Kufa city using remote sensing (RS) and Geographical Information System (GIS)
modern technologies. There are eight parameters considered in the analysis consists of residential area,
sewage areas, roads, a slope of the ground, surface water (river), green areas, historical, and land use. In
addition to that, the analytic hierarchy process (AHP) was used to apply the weights for each criterion and
sub-criterion, to get the best result and find the ideal site. At the first place, about thirty-eight sites have
been identified as suitable sites for wastewater plant throughout the study area which represented through a
red region color in a satellite image with its\' coordinate table. The best location will be chosen according to
the required land area on which the project is to be built from thirty-eight locations. However, a
complementary field study is critical to manifest the obtained results T with specialized engineers to find
the most effective site for WWTP between these sites.

The concept of Analogy varies with the number of basic inputs and the difference in the influence of the
basic inputs affecting their composition. In its general concept, architecture has two aspects related to the
nature of the formation of analogue thinking: the first is its physical entity, which reflects the visual and
visual values and the connection to the formal aspect, and the conceptual one related to the intellectual
aspect and the nature of its composition , Through the mutual influence between the reality of the external
entity and the nature of the ideas that man tries to reach, the research attempts to explore the concept of one
of the necessities of the doctrines and the architectural movements in the production of architecture
represented by analogue thinking The problem of research is based on [the need for a clear and specific
knowledge in the definition of the concept of analogue thinking as a design strategy and mechanisms for
the production of modulation according to analogue thinking at the level of form, structure and function in
the products of global architecture] Solving the research problem by selecting a set of global samples. In
this research, it is assumed that analogue thinking is an integral part of the analogy as a strategy and that to
achieve analogue thinking, the products must be content within the reference, A number of different global
samples with different time periods have been designed to be based on the strategy of analogue thinking,
the variation in the construction period and the variation in their design characteristics in terms of Formal,
functional and structural. This diversity and diversity of material production in the process of tracing the
purpose of the research in particular. In addition, from which these samples can be applied to apply the
concepts derived from the theoretical framework to achieve the hypothesis of research. The research aims
at building a comprehensive framework for the analogy strategy and revealing its role in the formation of
the architectural products, crystallizing a measurement tool for the analogy achieved as a method of thinking
and its impact on the continuity of the architectural products and applying it to the architecture to be the
reference of evaluation of architectural projects, whether in competitions or the academic field. That
analogue thinking depends on the transition of mind by incorporating more than one idea to form the creative
product achieved in reality, indicating the difference in the work of the analogy from the other creative
channels where analogue play plays a role in the creation and the bringing of unusual ideas, approach to
creative design and that man deals with architecture intellectually before the process of production is
configurable.

The biotic balance is a special strategy followed by the building, which helps it to stay and interact, and
perform vital functions at a constant and natural rate under suitable conditions or the possibility of making
them suitable, in the light of the general trend that seeks to preserve nature, as a result of the emergence of
concepts of sustainability and green architecture and applied models of polarization outside the environment
Which resulted in buildings that are not compatible with the environment and thus reduced environmental
performance of the building, emerged the research problem of \"lack of knowledge about the mechanisms of
living organisms to achieve a biological balance with the surrounding nature.\" The main objective of the
research was to \"build a cognitive perception about the mechanisms by which living organisms create a
biological balance with the surrounding environment.\" Therefore, the main research hypothesis was that
there is a similarity between the mechanisms used by living organisms to balance the surrounding nature
and the architectural solutions that the architect must follow to achieve the same Harmony with the
surrounding nature, \"and therefore adopted the methodology of research on two parts: First: the theoretical
study, which includes the introduction of concepts and considerations related to the concept of biological
balance, and knowledge of the mechanisms used by living organisms and try to apply in the field of
architecture, The study concluded that the strategies of living organisms in dealing with the surrounding
environment, along with the automatic architecture of marsh homes, is the basis of the main hypothesis and
its applicability.

This work was carried out on sediments in the Iraqi- Tigris river within the city of Baghdad. Three locations
were taken from the Tigris river. The first is at the entrance to Baghdad City (Al-Muthanna Bridge), the
second is in central Baghdad (Adhamiya) and the third is at the end of Baghdad (Diyala Jisr). The specimens
were taken from the banks of the Tigris river at 1.5 meters from the edge of the water and a depth of 2
meters. Sediments formed mainly from silica, with concentrations between 59 - 66%. Therefore, the study
focused on extracting the pure silicon element from these sediments. The extraction process of silicon from
the sediments was performed in two stages. The first is pyrometallurgy stage, in which the reduction of
silica was done by mixing pure aluminum powder with sediments at different mixing ratio (1:1, 1.5:1 and
2:1) sediments/aluminum and at temperatures (900, 950 and 1000)° C. The second stage was
hydrometallurgy (leaching process), this process was carried out by using different concentrations (3,4 and
5)M of sulfuric acid to obtain silicon element with purity 98. 9%. The results show that the efficiency of
extraction silicon from sediments of the Tigris river is greater than (88%).