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Effect of different acids surface treatments and thermocycling on shear bond strength of composite resin to feldspathic ceramic
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Background: the aim of this study was to evaluate the effect of different surface acids treatments (37%phospjoric acid, 5%hydrofluoric acid, 1.23 acidulated phosphate fluoride) of feldspathic ceramic VITA 3D MASTER , and the effect of thermocycling on shear bond strength using a ceramic repair kit (ivoclar/vivadent). Material and Methods: sixty Nickel-Chromium metal base plates were prepared(9mm diameter,3mm depth) using lost wax technique, 2mm thick layer of ceramic(VITA 3D MASTER) fused to metal plates, all specimens were embedded in acrylic resin blocks except their examined surfaces and divided into 3 main groups 20 specimens each, Grp A: treatment with 37%phosphoric acid for 2 mins, Grp B: etching with 5% hydrofluoric acid for 2mins, Grp C: etching with 1.23% acidulated phosphate fluoride for 10 mins; monobond-plus, heliobond, resin composite(Tetric EvoCeram) were applied to each specimen according to manufacturer's instruction using transparent split mold(5mm diameter, 4 mm height); specimens were stored in 37OC distilled water for 12 weeks, 10 specimens of each group were subjected to thermocycling between 5 oC and 55 o C for 800 cycles with 30s dwell time; shear bond strength was determined by a universal testing machine (instron 1122) at a cross head speed 0.5mm/min; One way ANOVA test, LSD test and student-t test were used to analyze shear bond strength. Results: Mean shear bond strength values for the tested groups were: A1= 11.65±0.68 Mpa, A2=10.88±0.58 Mpa, B1=17.93±0.41 Mpa, B2=17.42±0.35 Mpa, C1=15.17±0.61 Mpa, C2=14.51±0.48 Mpa ; one way ANOVA test showed highly significant difference among groups; LSD test revealed that the use of 5% HF for ceramic surface treatment(GB) was highly significant than the treatment with 37%PA(GA) or 1.23%APF(GC) respectively and the use of 1.23%APF(GC) was highly significant than the use of 37%PA(GA); Student t- test showed a significant difference between subgroups of the same group with and without thermocycling. Conclusion: ceramic surface treated with 5% HF acid for 2 mins recorded the highest shear bond strength, followed by surface treatment with 1.23% APF for 10 mins, most specimens treated with 5%HF showed cohesive failure with in ceramic while specimens treated with 1.23%AFP showed more (adhesive/cohesive) failure than adhesive or cohesive alone, and specimens treated with 37% PA showed nearly 50:50 adhesive and combination failure, thermocycling reduced the bond strength of each group significantly

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Publication Date
Sun Nov 26 2017
Journal Name
Journal Of Engineering
Numerical Study of Heat Transfer Enhancement for a Flat Plate Solar Collector by Adding Metal Foam Blocks
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Numerical study has been conducted to investigate the thermal performance enhancement of flat plate solar water collector by integrating the solar collector with metal foam blocks.The flow is assumed to be steady, incompressible and two dimensional in an inclined channel. The channel is provided with eight foam blocks manufactured form copper. The Brinkman-Forchheimer extended Darcy model is utilized to simulate the flow in the porous medium and the Navier-Stokes equation in the fluid region. The energy equation is used with local thermal equilibrium (LTE) assumption to simulate the thermofield inside the porous medium. The current investigation covers a range of solar radiation intensity at 09:00 AM, 12:00 PM, and 04:00

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Publication Date
Wed Jan 30 2019
Journal Name
Journal Of The College Of Education For Women
Variables Impact Spatial Change for Rural Settlement in Al-Hammer Marsh-Land in Governorate of Thi-Quar
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During the period 1970-2006 the Marshes-land region was exposed to several change into many sides of vanishing steeling and growth as follow :
1- Drying this region after 1991,and re-flooded again during 2003. Many other large Marsh-land, like al-Hawaisa was dried by cutting off inlet-water fed from Iran sources .As asqunance there are transferred to different kinds of swamps ,followed by major change in the structure of the region as the rural settlement concerned. Rural settlement in this area starts new push of migration. The research did not take that in consideration in this thesis because some others took it in details in some thesis and researches. The situation of Marsh-land is getting anew face after those major changes which

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Publication Date
Fri Feb 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
The role of investment climate indicators in stimulating economic growth: a standard study For Malaysia 1990-2016
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In globalization, the world became open area to competition for the attractive of investment, and the abilities of each country to win the confidence of investors depend upon the preparation to optimize circumstances.   The competitiveness is an essential means of expanding the capacity of developed to coexist in an international environment characterized by globalization. While competition describes the market structure, the behavior of investors and business, competitiveness is interested in the evaluation of business performance or countries and compare them in the conditions of competition available in these markets. Regarding Malaysia, which is depend on FDI-Export- Led Growth strategy,  it has taking on diffe

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Crossref
Publication Date
Mon Jan 01 2007
Journal Name
Journal Of Educational And Psychological Researches
Evaluating the Professional Efficiency of Primary School Teachers in Teaching Rafidain English Course for Iraq, Book I
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      Teaching techniques are the vehicles, which are used by teachers to help pupils learn and gain experiences and create positive classroom activities, as much as these techniques are varied, they lead to successful and fruitful learning in the foreign language. They help teachers achieve their objectives (Asowrth, 1985: 124).

    The English language teacher's work is an active and purposeful one when he can plan carefully and frequently make the necessary changes in the contents and methods of teaching programme to fit the interest and needs of pupils. It seems that the majority of primary English teachers' interests does not go far in planning their work, and do not understand which o

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Publication Date
Fri Sep 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
'The Role of Ambidextrous Leadership' Behaviors in Enhancing Organizational Energy': An Analytical Research General AL-Faris Company
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             The current research aims to identify the impact of ambidextrous leadership behaviors on organizational energy in Al-Faris Company. The descriptive analytical method was used as a research approach. Adept leadership includes two dimensions (open leadership behaviors and closed leadership behaviors), and organizational energy includes three dimensions (emotional energy, physical energy, and cognitive energy ). The research sample included all the administrative leaders (General Manager, Associate General manager, Department Manager, Division Official  ) in AL-Faris Company / the Iraqi Ministry of Industry. The researcher distributed (74) valid questionna

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Crossref
Publication Date
Thu Sep 01 2011
Journal Name
Journal Of Economics And Administrative Sciences
Comparison of BASE methods with other methods for estimating the measurement parameter for WEBB distribution using simulations
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  Weibull distribution is considered as one of the most widely  distribution applied in real life, Its similar to normal distribution in the way of applications, it's also considered as one of the distributions that can applied in many fields such as industrial engineering to represent replaced and manufacturing time ,weather forecasting, and other scientific uses in reliability studies and survival function in medical and communication engineering fields.

   In this paper, The scale parameter has been estimated for weibull distribution using Bayesian method based on Jeffery prior information as a first method , then enhanced by improving Jeffery prior information and then used as a se

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Crossref
Publication Date
Thu Oct 17 2024
Journal Name
South Eastern European Journal Of Public Health
The Level of Serum Selenium in Patients with Cervical Intraepithelial Neoplasia in Medical City/ Baghdad Teaching Hospital
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Introduction: Selenium is an essential trace element involved in different physiological functions of the human body. An inverse relationship between serum selenium levels and cervical intraepithelial neoplasia has been reported. cervical intraepithelial neoplasia is regarded as a potentially premalignant transformation of squamous cells of the cervix. Objectives: To evaluate the relationship between the serum level of selenium and cervical intraepithelial neoplasia. Methods: A case-control study was conducted at Baghdad Teaching Hospital and Iraqi National Cancer Research Center in the University of Baghdad during the period from July 2021 to July 2022. A convenient sample of 100 women was enrolled in the current study and included

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Crossref
Publication Date
Tue Oct 01 2024
Journal Name
Journal Of Engineering Science And Technology
NUMERICAL SIMULATION OF SHEET PILES AS A SEEPAGE CUTTER OFF: AL-KIFIL REGULATOR AS A CASE STUDY
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Sheet piles are necessary with hydraulic structures as seepage cut-off to reduce the seepage. In this research, the computational work methodology was followed by building a numerical model using Geo-Studio program to check the efficiency of using concrete sheet piles as a cut-off or reducer for seepage with time if the sheet piles facing the drawdown technique. Al-Kifil regulator was chosen as a case study, an accurate model was built with a help of observed reading of the measuring devices, which was satisfactory and helped in checking the sheet piles efficiency. Through the study, three scenarios were adopted (with and without) drawdown technique, it was found that at the short time there's no effect of the drawdown technique on

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Scopus
Publication Date
Wed Jan 01 2014
Journal Name
كلية التربية -الجامعة المستنصرية
study the electron drift velocity in gas mixtures of SF6 with N2 obtained from Boltzmann equation analysis
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Publication Date
Tue Jan 09 2018
Journal Name
Research Journal Of Pharmacy And Technology
Sequencing of Mitochondrial COI gene in new Iraqi record Paropeas achatinaceum L. P. Feiffer, 1846, Gastropoda: Subulinidea
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Fifty snails of Paropeas achatinaceum specimens were collected and classified from four areas in Baghdad-Iraq from the period between June and July, 2017. The snails were divided into two groups (each group contain 25 snails). Two environment conditions were used in this study. Natural environment considered as control and experimental environment contains Citrus sinensis (L.) roots as snail’s source food. The comparison result between snail weights in the nature and experimental environment was not significant (0.497, 95% confidence interval [CI] 0.01209–0.02309). Also, the comparison between snail weights in the nature environment and the food mean weight was significant (0.014, 95% confidence interval [CI] 0.00591-0.04109), while the

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