Background: Fluoridated acrylic resin material can present more stable properties when compared with conventional one.The most widely used fluoride –containing substance added to dental resin materials is sodium fluoride (Naf). This study evaluated the effect of Naf in different concentration to the acrylic resin denture base material and its effect on tensile strength ,modules of elasticity with long –term water immersion (after 4 months immersion in de-ionized water) Materials and methods: Eighty specimens from dumbbells shaped metal pattern for tensile strength test were preparedaccording to ISO 527: 1993 plastic –Determination tensile properties ,in dimensions(60mm, 12mm, 3 ± 0.2mm) length, width and depth respectively were allocated to two groups according to water immersion there were 40 specimens before immersion and 40 specimens after water immersion for 4 months in de-ionized water(the de-ionized water was changed every day),these two groups were sub divided in to four groups according to the concentration of Naf,Naf powder were added to monomer of acrylic in concentrations of 1%,2%and 5% Naf .0% Naf(control group) ,then mixing were done with polymer according to manufacture instructions ,the conventional flasking ,packing procedure were used following that (fast cycle). For tensile strength test the measuring was done by Instron machine,the values of modulus of elasticity were obtained from tensile test . Results: Results showed that the addition of sodium fluoride to acrylic resin material werelower the tensile strength and modules of elasticity with highly significant differences p<0.01 when compared to control group regardless the concentration of Naf,But after immersion (for 4 month ) the tensile strength and modules of elasticity increased in comparison to groups before immersion (with highly significance differences p <0.01 ), highly significance differences (p <0.0)were found between groups after and before immersion in all concentrations except for tensile strength between 1%Naf and 2%Naf after immersion there was no significant differences(p>0.05), and for modules of elasticity between control and 1%Naf, 1% Naf and 2%Naf( after immersion ),there was only significant differences between them(p<0.05). Conclusions: Addition of fluoride to acrylic resin material lower the tensile strength and modules of elasticity when compared to control group regardless the concentration of Naf, But after immersion (for 4 months ) the tensile strength and modules of elasticity increased in comparison to groups before immersion (with highly significance differences p <0.01).
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This study is an approach to assign the land area of Kirkuk city [ a city located in the northern of Iraq, 236 kilometers north of Baghdad and 83 kilometers south of Erbil [ Climatic atlas of Iraq, 1941-1970 ] into different multi zones by using Satellite image and Arc Map10.3, zones of different traffic noise pollutions. Land zonings process like what achieved in this paper will help and of it’s of a high interest point for the future of Kirkuk city especially urban
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This study aims at suggesting flow as a strategy for training female EFL student-teachers in the teaching training course and finding out the effect of this strategy on their performance and their flow state. The training course syllabuses will be constructed according to the flow nine factors and the teaching skills. The measurement tools are the student-teacher performance checklist that has already been used by the department of English language and SHORT Flow State Scale (S FSS-2). The study population is represented with the (60) female student-teachers/ fourth stage/ evening studies at theEnglish department /college of education for women/the University of Baghdad. The study is used the experimental design in that (30) of the student-
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The present study designed to determine the ethanolic extract of Cyperus rotundus on Liver in Albino Male Mice . In the present study 18 Male mice were used they divided into six groups ( 1st group consedered control group , 2nd group injected by 250 mg/ml from extract , 3th group injected by 300 mg/ml from extract , 4th group injected by 350 mg/ml from extract , 5th group injected by 400 mg/ml from extract and the 6th group injected by 450 mg/ml from extract ) . the expermint lasted for two days and the doses gived by intraperitonial injection . showed from the study results that ethanolic extract for Cyperus rotundus have negative effect on Liver tissue in 250 , 300 , 350 mg/ml concentrations when comparsion with control group . the re
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A computational investigation is carried out in the field of charged –particle optics with the aid of numerical analysis method using the personal computer. The work is concerned with the design of electron gun with space-charge effect. The Finite element method (FEM) used in the solution of Poison's equation for determine the axial potential distribution of the two-electrode immersion lens operated under zero magnification condition , and from the solution of the paraxial ray equation the optical properties such as the focal length , spherical and chromatic aberration coefficients are determined, also a calculation of the brightness and perveance for the lens. The electrodes geometry was determined in two and three dimensi
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Listening comprehension of Iraqi EFL college students are not given time for practice, and incorporate in the programme of the Department of English, therefore, students are not well-prepared to comprehend the spoken language also the Iraqi EFL College students are deficient in comprehending the spoken English. So, listening strategies require a larger amount of consistent practice. The present study aims at finding out the effect of teaching the proposed listening strategies programme on EFL university students' listening comprehension. The sample consists of 104 of 1st year college students at the Department of English Language, College of Education Ibn-Rushed for Humanities. The programme deals with the following strategies: summrazing-n
... Show MoreThe aim of the research is to demonstrate the extent of the impact of resource consumption accounting technicality as an administrative technique that is compatible with the rapid developments and changes in the external environment, with the information it provides and scientific foundations in the allocation of indirect costs, and the identification and measurement of idle energy and its costs in a way that contributes to the rationalization of pricing decisions in economic units. In light of the intense competition and the multiplicity of alternatives, and to achieve this goal, a random sample was chosen.