Bobbin friction stir welding (BFSW) is a variant of the conventional friction stir welding (CFSW); it can weld the upper and lower surface of the work-piece in the same pass. This technique involves the bonding of materials without melting. In this work, the influence of tool design on the mechanical properties of welding joints of 6061-T6 aluminum alloy with 6.25 mm thickness produced by FSW bobbin tools was investigated and the best bobbin tool design was determined. Five different probe shapes (threaded straight cylindrical, straight cylindrical with 3 flat surfaces, straight cylindrical with 4 flat surfaces, threaded straight cylindrical with 3 flat surface and threaded straight cylindrical with 4 flat surfaces) with various dimensions of the tool (shoulders and pin) were used to create the welding joints. The direction of the welding process was perpendicular to the rolling direction for aluminum plates. Tensile and bending tests were performed to select the right design of the bobbin tools, which gave superior mechanical properties of the welded zone. The tool of straight cylindrical with four flats, 8 mm probe and 24 mm shoulders diameter gave better tensile strength (193 MPa), elongation (6.1%), bending force (5.7 KN), and welding efficiency (65.4%) according to tensile strength.
The study aimed to explore the effectiveness of using rational judgment strategy in teaching science to develop scientific thinking for second-grade students. The researcher utilized the quasi-experimental approach based on (the pre/post designing) of two groups: experimental and control. As for tools: a test of scientific thinking prepared by the researcher that proved its verification of their validity and reliability. The test applied on a random sample of (66) students, divided into two groups: (34) experimental, and (32) control. The results showed that the experimental group outperformed the control group in the post-application of the scientific thinking test, In each skill separately, and in the total skills. The study recommende
... Show MoreSocial protection meets different aspects of the needs of vulnerable groups, such as the economic, health, education, and family relations and ties in the Iraqi society. This is because vulnerable groups have suffered from social and economic influences that have negative implications on the social reality as a whole. Poverty is a case in point, which paved the way to frequent setbacks that have led to social structure instability. Accordingly, the present study aims to examine the role and effect of the Net of Social Protection Program in equally distributing social protection to curb or mitigate any negative consequnces that might happen to the poor segments and vulnerable people, who are succeptible to shocks, such as: the orphans, un
... Show MoreThe world and the business environment are constantly witnessing many economic changes that have led to the expansion of the business' volume due to mergers and the increase in an investments volume and the complexity of business and the transformation of some systems, which was reflected on the size of the risk and uncertainty which led to necessity of a presence of transparent and objective accounting information In the way that reflects the financial performance of the economic units to be available to all users of that information, therefore, The need for the existence of indicators for transparency in the disclosure of accounting information that these units adhere to. Standards & Poor's indicators, which included items
... Show MoreWe need to know the basic facts concerning planning top and bottom limits including any critical levels or the threshold over which the cost would be much higher for land development. Therefore this paper concerned with Baghdad Municipality decision No.2/1004 dated 7/12/2004. The reason behind this decision is the hope to face up at least in the severe housing crisis in the city of Baghdad. This paper attempts to know the attitude of the local community in the general through a field study of people living near such dwelling where third floors are added of. This might indicate any positive or negative effects whether on short or long-term including its effect on the theoretical side including the population growth of Baghdad, the
... Show MoreThe contemporary art culture is considered a resultant of preceding human civilizations from the early days. At the same time, it got closer to the local privacy, because the contemporary Iraqi potter worked hard to create new art, refusing to base his art on the early works, creating art pieces that contains properties to inherited art and their form significance, in order to create a new identity of his own, bringing an empowerment to his deepened civilization, with the goal to create national identity ideas from one hand, and entity and locality from another. Europeans also followed the direction of our civilization, such as (Picasso, Henry Moore, Barbra Hurth, Brankouzi, Hans Arp,..etc). From this point of view comes the importance o
... Show MoreThis study has been done for testing the effectiveness and efficiency of probiotic in its ability to inhibit Aspergillus flavus , which secretes the aflatoxin B1 and compare it with materials that were approved to be effective in the inhibition of the growth of fungi and break down and reduction of mycotoxin. these are the filax substance and ozone gas. A laboratory experiment has been conducted to determine the isolates out of the fungus producing the aflatoxin B1.the isolate producing aflatoxin B1 has grown on the yellow corn seed. the probiotic was added along with the filax and they have been exposed to ozone gas and then they were stored from 30 days. A bio test was con conducted to knw the effects of biological toxin on the broiler me
... Show MoreThe current research aims to identify the impact of the (Landa) model on acquiring grammatical concepts among students of the College of Administration and Economics, University of Baghdad, and to achieve the research goal, the researcher has set the following hypotheses: There are no statistically significant differences at the level of significance (0.05) between the average degrees Students of the experimental group who studied the Arabic language according to the (Landa) model and the marks of the students of the control group who studied the same subject in the usual way in the post test, there are no statistically significant differences at the level of significance (0.05) in the average differences between the test scores before and
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Abstract
The human mind knew the philosophy and logic in the ancient times, and the history afterwards, while the semiotics concept appeared in the modern time, and became a new knowledge field like the other knowledge fields. It deals, in its different concepts and references, with the processes that lead to and reveals the meaning through what is hidden in addition to what is disclosed. It is the result of human activity in its pragmatic and cognitive dimensions together. The semiotic token concept became a knowledge key to access all the study, research, and investigation fields, due to its ability of description, explanation, and dismantling. The paper is divided into two sections preceded by a the
... Show MoreAmongst the literary writers who used their art to direct the attention towards the issue of woman and her rights in a proper life is the English poet and novelist Thomas Hardy (1840-1928), who has been praised for his “openness to the feminine principle” 1 as Irving Howe put it. Hardy’s wide readings have changed his way of dealing with and thinking about so many critical issues which started to float on the surface of the English society during the mid and late of the 19th century. His readings for a number of writers, who seem of huge impact on his writings as he later admits that – “[his] pages show harmony of view with
... Show MoreThe study aimed to prepare a set of qualifying exercises to improve the muscular strength of the muscles surrounding the ankle joint by applying different resistances according to the nature of the movement of this joint, which is one of the second moving joints (flexion, extension and rotation of the right and left) in order to increase the efficiency of all muscles working on this joint according to those movements and identification On the impact of these exercises and assume that there will be statistical differences between the two tests of the research sample. The researcher used the semi-articulated experimental method with a pre- and post-test for one group. The injury was evaluated on the women's national team players durin
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