Abstract
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 ...
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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) mmmin, 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 mmmin 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
Abstract
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 ...
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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.
Abstract
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 ...
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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 Total-Harmonics-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.
Abstract
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 ...
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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.
Abstract
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 ...
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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.
Abstract
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 ...
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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. And 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.
Abstract
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 ...
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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.
Abstract
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 in central Baghdad (Adhamiya) and the third at the end of Baghdad (Diyala Jisr).The ...
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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 in central Baghdad (Adhamiya) and the third 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 meter. The sediments contain in the three locations have a slight difference in concentrations of compounds. Sediments formed mainly from silica, which concentrations were 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 performed 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, which involved chemical reduction using at different concentrations (3,4 and 5M) of sulfuric acid to obtain silicon element with purity, 98. 9%. The efficiency of extracted silicon from sediments of Tigris river is ≥ (88%).
