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 traditional method adopted in the preparation of the general budget in Iraq is not consistent with developments in the size specification response and spending and the associated weakness in the size of the amounts earmarked for investment projects which could adversely affect future generations and not to enable them to continue the development, which requires talking to estimate the adoption of style public expenditure in the state budget and reduce waste and extravagant where and invest public revenues of the state in investment projects and preservation of the environment and natural resources in order to ensure the benefit of future generations system, according to the system serves to achieve the overwhelming majority of member
... Show Morethe first part of the research involves investigate the aspect of the radiation superposed on the one bright soliton pulse propagated on ideal single mode
Semi-empirical methods were applied for calculating the vibration frequencies and IR absorption intensities for normal coordinates of the {mono (C56H28), di (C84H28), tri (C112H28) and tetra (C140H28)} -rings layer for (7,7) armchair single wall carbon nanotube at their equilibrium geometries which were all found to have D7d symmetry point group.
Assignment of the modes of vibration (3N-6) was done depending on the pictures of their modes by applying (Gaussian 03) program. Comparison of the vibration frequencies of (mono, di, tri and tetra) rings layer which are active in IR, and inactive in Ramman spectra. For C-H stretching vibrat
... Show Moreيهدف البحث إلى تقييم الكفاءة الوظيفية لمؤسسات التعليم الأهلي في أداء وظيفتها بمستوى عالٍ لتشبع حاجة سكان المدينة الذين فضّلوا التعليم الأهلي على التعليم داخل المؤسسات الحكومية مما أدى إلى انتشارها، وصولا إلى أهم الآثار المترتبة على ذلك الانتشار إذ نافست فيه مؤسسات التعليم الحكومي، بل وتنافست المؤسسات الأهلية فيما بينها لتقديم أفضل خدمة تعليمية للصراع من أجل البقاء، وتهدف أيضا إلى إظهار الوجه السلبي ا
... Show MoreThe present study aimed to investigate the effect of re-operations engineering business in continuous improvement, as the rapid development of service activities generally private and the great diversity in the goals of its operations and programs of the university and the service has led to the increasing importance of re-operations engineering business as well as continuous improvement so began to study the relationship between the re engineering and continuous improvement of university service, and applied study on a sample of professors from the faculties of administration, economics and law. Find and reach to several conclusions, notably that the preparation of the teaching staff training sessions on how to use modern teaching
... Show MoreThe research aims to know the concept of politic behavior as one of the important behaviours in the different fields and sectors. It is considered to be part of the organizatial work to face the expected risks. It includes two group of factors personal (self –monitors, locus of control ,expectation s of success, perceived job alternatives)and organizational(promotion ,division resources,role ambiguity ,democratic decision)studied by the researcher in the frame of the relationship with the variable of display continuous trust matain which includes two variable (build trust mantain, display trust continuouness)through applied frame by random sample consists of (90)employee at Farouq State
... Show MoreThe present research aims to identify the social responsibility of the kindergarten teachers of the civil and governmental schools (comparative study)? For the purpose of achieving the objectives of the research, the following formulas were formulated:
- Are there statistically significant differences at the level of (0.05) among the kindergarten teachers in the social responsibility scale?
The current research was limited to kindergarten teachers (governmental and non-governmental) in the Directorate General of Education Baghdad Rusafa / Second.
The main research sample consisted of (100) teachers, (50) teachers from government kindergartens and (50) female kindergarten teache
... Show MoreThis study was carried out in Artificial Insemination Center of Iraq to revealed FMD disease effect on some seminal attributer parameters of 14 imported Holstein bulls divided to three groups according to different reproductive efficiency (four High, five medium and five weak). Results showed that FMD disease had significant (P < 0.05) adverse effect on most seminal attributer parameters, mass, individual motility and sperm concentration / ml during post disease in first of two, four, all months of high, medium and weak semen quality bulls respectively .but semen volume didn’t influenced significantly with this disease. So semen collection should be suspended until resume normal fertility of sperm, after two, four month of high and
... Show MoreThe educational service industry is one of the most negatively affected industries by the spread of the COVID-19 pandemic. Government agencies have taken many measures to slow its spread, and then restrict movement and gatherings and stop recreational activities. Furthermore, the repercussions of the curfew had a significant impact due to the interruption in actual attendance for students and employees, and the severity of the Covid-19 crisis and its (economic, social, security, humanitarian and behavioral) effects on all societies and work sectors is no secret to anyone. Iraq, like other countries, was also affected by the negative impact of Covid-19 pandemic in all fields of institutional work, especially public fields, and specifically t
... Show More