Electrical Discharge Machining (EDM) is a widespread Nontraditional Machining (NTM) processes for manufacturing of a complicated geometry or very hard metals parts that are difficult to machine by traditional machining operations. Electrical discharge machining is a material removal (MR) process characterized by using electrical discharge erosion. This paper discusses the optimal parameters of EDM on high-speed steel (HSS) AISI M2 as a workpiece using copper and brass as an electrode. The input parameters used for experimental work are current (10, 24 and 42 A), pulse on time (100, 150 and 200 µs), and pulse off time (4, 12 and 25 µs) that have effect on the material removal rate (MRR), electrode wear rate (EWR) and wear ratio (WR). A Minitab software environment was used to adopt Taguchi method to analyze the effect of input on output parameters of EDM. The results of the present work showed that the best of MRR in copper and brass electrodes with (current 42 A, pulse on time 100 µs and pulse off time 25 µs) are (84.355×10-3 g/min) and (43.243×10-3 g/min) respectively, and the MRR predicted by Taguchi are (86.1751×10-3 g/min) in copper electrode by using the parameters with (current 10 A, pulse on time 200 µs and pulse off time 25 µs) and (43.2979×10-3 g/min) in brass electrode at current 42 A, pulse on time 100 µs, and pulse off time 25 µs. The lowest EWR occurs with a value of (1.4510×10-3 g/min) with (current 10 A, pulse on time 100 µs, pulse off time 4 µs) variables when using a copper electrode. The highest WR (2.602508) was found for the brass electrode with (current 24 A, pulse on time 200 µs, pulse off time 4 µs) variables.
The present study aimed to impact Strategy mental map in the acquisition of geographical concepts at the fifth-grade students in the literary geography classes. To achieve the objectives of the research formulated researcher null hypothesis (no statistically significant difference at the level (0.05) between the average scores of students who Adersna using a mind map, and who Adersna using the method usual in the acquisition of concepts geographic fifth grade literary). Has chosen researcher design Altjeribeachtar researcher Design The partial adjustment for both experimental and control groups Pachtearlakedzab concepts. The sample Seateetmthel graders secondary schools under the Directorate General of Educational Baghdad Rusafa II has c
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لاحظ الباحث عن طريق خبرته – المتواضعة- في أثناء عمله في ميدان التدريس في أقسام القرآن الكريم والتربية الإسلامية ان هناك ضعفاً في المستويات وتدنياً واضحاً في التفكير المنظومي للطلبة في مادة الإعجاز القرآني، ويرى الباحث أن هذا التدني يعود إلى أسباب عديدة من أبرزها: طرائق تدريس المادة، وغزارة المادة الدراسية، وصعوبة استيعابها في الوقت القصير المخصص لها، وان
... Show MoreThe world witnessed variables influenced on entirely education essential mean to grantee the required adaption of inner and external motivations circumstances this gives us opportunity of the best selection means to achieve the goals for progress individual and community .
From here appeared the needs of scientific study interest in new styles of education locate the old place that become non able to granting students and their tendency n
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Nations managed today to achieve progress in the field of modern technology. Science has changed many beliefs and trendiness that people have held for long time, skills and scientific thinking developed, and made scientific observation and experiment replace narration and taking from others. That is attributed to examining the educational systems searching for the locations of defect, and shortage.
In the light of educational modernizations, many models of teaching incliuding a model for social tracing attributed to Herbart Thelen, which is a model to develop skills of social participation in the democratic process (Al-Khawalda,1993,335).
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The archaeological and religious sites play a prominent role in the rest of the other tourist activities as cultural and spiritual needs that can not be dispensed with. Archaeological sites represent cultural origins of the nation. Religious sites represent the state of man's orientation to God in places of worship . The focus was on the city of Babylon because it is an ancient city and tourist because of its characteristics and elements. The importance of the city of Babylon is illustrated by highlighting its archeological and religious status through its geographical distribution. This gives the subject special importance for the purpose of knowing the city's important sites. And come out with a number of results and a set of recommend
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Background: Waterpipe tobacco smoking has become common especially among young people, Waterpipe smoking misconcepted as a safer mean of smoking, so in this study we will highlight the effect of Waterpipe smoking ‎on periodontal and oral health.‎ Materials and method. The selected ‎‎‎100 male subjects of 30-40 years, ‎categorized into 4 groups (each group ‎‎25 subject): Waterpipe smoker ‎with ‎healthy periodontium, ‎Waterpipe smoker ‎‎with chronic periodontitis, Non-‎‎smoker ‎with healthy periodontium and Non-smoker ‎with chronic periodontitis. Whole ‎unstimulated ‎saliva was collected. Clinical measurements: plaque ‎index
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Objective: Per-implantitis is one of the implant treatment complications. Dentists have failed to restore damaged periodontium by using conventional therapies. Tissue engineering (stem cells, scaffold and growth factors) aims to reconstruct natural tissues. The paper aimed to isolate both periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMMSCs) and use them in a co-culture method to create three-layered cell sheets for reconstructing natural periodontal ligament (PDL) tissue. Materials and methods: BMMSCs were isolated from rabbit tibia and femur, and PDLSC culture was established from the lower right incisor. The cells were co-cultured to induce BMMSC differentiation into PDL cells. Cell morphology, stem cel
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Backgrround:: Cholera is gastroenteritis caused by enterotoxin producing Vibrio cholera. Cholera is predominantly a waterborne disease especially in countries with inadequate sanitation. Several rapid methods have been developed and used to detect V. cholerae serotypes directly from stools.
Objjecttiives:: to evaluate a rapid and accurate method for the diagnosis of cholera caused by V. cholerae O1 and O139 serogroups d to find the incidence of sporadic cases of cholera in Baghdad.
Metthods:: Sixty four stool samples were collected from four hospitals in Baghdad. The age of patients ranging from two months to 12 years, 26 were females and 38 males. Immunochromatographic visual test for qualitative detection of O1 and /or O139 serog