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The Effect of Restriction Shape On Laminar Natural Convection Heat Transfer In A Vertical Circular Tube
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Natural convection heat transfer is experimentally investigated for laminar air flow in a vertical circular tube by using the boundary condition of constant wall heat flux in the ranges of (RaL) from (1.1*109) to (4.7*109). The experimental set-up was designed for determining the effect of different types of restrictions placed at entry of heated tube in bottom position, on the surface temperature distribution and on the local and average heat transfer coefficients. The apparatus was made with an electrically heated cylinder of a length (900mm) and diameter (30mm). The entry restrictions were included a circular tube of same diameter as the heated cylinder but with lengths of (60cm, 120cm), sharp-edge and bell-mouth. The surface temperature along the cylinder surface for same heat flux would be higher values for circular restriction with length of (120cm) and would be smaller values for bell-mouth restriction. The results show that the local Nusselt number (Nux) and average Nusselt numberare higher for bell-mouth restriction and smaller values for (120cm) restriction. For all entry shape restrictions, the results show that the Nusselt number values increases as the heat flux increases. From the present work an empirical correlations were obtained in a form of (Log) versus (Log) for each case investigated and obtained a general correlation for all cases which reveals the effect of restriction existence on the natural convection heat transfer process in a vertical circular tube.

 

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Publication Date
Thu Jun 30 2022
Journal Name
Iraqi Journal Of Laser
PDF Influence of Er:Cr;YSGG laser Desensitization on SBS of resin cement to dentin
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Background: Crown preparation of vital teeth involve the removal of a sound tooth structure, and when enamel removed this lead to exposed dentin with an   increase in the number of open dentinal tubules also the diameter of dentinal tubules will increase, furthermore lead to increase movement of fluids inside the tubules all that causes post preparation sensitivity. The aim of this study is to evaluate the effect of desensitizing by Er:Cr:YSGG laser on shear bond strength of prepared tooth and resin cement. Materials and methods: Thirty sound maxillary premolars, grouped into three groups(n=10). Group A is the control group, group B irradiated by Er:Cr:YSGG laser with (0.25 W, 20 Hz, 1

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Publication Date
Sun Jul 06 2014
Journal Name
Journal Of Educational And Psychological Researches
The influence of Online Training Courses on Iraqi EFL Instructors Teaching and Learning Process
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For over a decade, educational technology has been used sparingly in our schools and universities. Online training courses have been used since 2003 to fill the gaps in our learning system and to add extra program besides classroom learning. This paper aims to investigate the Iraqi EFL instructors’ participating in online training courses and its influence on the process of teaching and learning.

       The sample of present study consists of 30 instructors from University of Baghdad. The questionnaire of sixteen items was constructed. After ensuring validity and reliability of questionnaire, it was applied on March 2013 and the result shows that most of instructors improve their teaching methods b

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Publication Date
Wed Dec 30 2015
Journal Name
College Of Islamic Sciences
The impact of Arab civilization   On the first century AH
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The influx of Arab Qahtani and Nizari tribes continued to the countries of Baluchistan and the Levant in pre-Islamic times until the Levant became open to the Arab-Islamic tide during the first century AH. The Islamic Orient until the early Islamic Arab Army reached the western borders of China. What we will see in the folds of the search.

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Publication Date
Sun Jul 01 2012
Journal Name
Journal Of Educational And Psychological Researches
A comparative study between the emotional responses in patients with blood pressure on a scale of music types characteristics compared with responses to some Healthy patients
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The problem of the study and its significance:

           Due to the increasing pressures of life continually, and constant quest behind materialism necessary and frustrations that confront us daily in general, the greater the emergence of a number of cases of disease organic roots psychological causing them because of severity of a lack of response to conventional treatments (drugs), and this is creating in patients a number of emotional disorders resulting from concern the risk of disease

 

     That is interested psychologists and doctors searchin

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Publication Date
Sun Jun 05 2016
Journal Name
Baghdad Science Journal
Adsorption and Thermodynamic Study of Direct Blue 71 Dye on to natural Flint Clay from Aqueous Solution
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The remove of direct blue (DB71) anionic dye on flint clay in aqueous solution was investigated by using a batch system for various dye concentrations. The contact time, pH, adsorbent dose, and temperature was studied under batch adsorption technique. The data of adsorption equilibrium fit with isotherm Langmuar and Freiundlich ,when the correlation coefficient used to elucidate the best fitting isotherm model. The thermodynamic parameters such as, ?Hº ,?Sº and ?Gº. Thermodynamic analysis indicated that the sorption of the dyes onto Flint clay was endothermic and spontaneous.

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Publication Date
Tue Dec 31 2019
Journal Name
Journal Of Economics And Administrative Sciences
The Reflection of the application TD-ABC approach on profits persistence Applied study in the General State of Hydraulic Industries Factory of Plastic*
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The interest of many companies has become dealing with the tools and methods that reduce the costs as one of the most important factors of successful companies, and became the subject of the attention of many economic units because of the impact on the profits of company, and since the nineties of the last century the researchers and writers gave great attention to this subject, especially in light of the large competition and rapid developments in cost management techniques, as well as the wide and significant change in production methods that have been directed towards achieving customer satisfaction, all this and more driven by economic units in all sectors whether it is service or productivity to find methods that would reduc

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Publication Date
Wed Mar 20 2019
Journal Name
Journal Of Legal Sciences
Sale Based on an Open Price – A Comparative Study
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The ultimate goal of any sale contract is to maximize the combined returns of the parties, knowing that these returns are not realized (in long-term contracts) except in the final stages of the contract. Therefore, this requires the parties to the contract to leave some elements open, including the price, because the adoption of a fixed price and inflexible will not be appropriate to meet their desires when contracting, especially with ignorance of matters beyond their will and may affect the market conditions, and the possibility of modifying the fixed price through The elimination is very limited, especially when the parties to the contract are equally in terms of economic strength. Hence, in order to respond to market uncertainties, the

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Publication Date
Mon Apr 01 2019
Journal Name
Journal Of Educational And Psychological Researches
The Effectiveness Of A Proposed Program For Developing The Creative Abilities Of The Students At The University Of Tabuk And Its Effect On The Creative Output Of The Neom Project.
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The aim of this study was to measure the effectiveness of a proposed program to develop the creative abilities of the students of Tabuk University and its impact on the creative output of the NEOM project. The sample of the study consisted of (50) university students divided into two groups: an experimental group of 25 students who receive the proposed training program, and control group of (25) students.

 To achieve these objectives, the researcher designed and developed tools to collect the required data, which were verified their validity and reliability.

The descriptive statistics of mean, standard deviations, correlation coefficient, T test for the associated sample were used in the analysis of the results of th

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Publication Date
Sun Apr 04 2010
Journal Name
Journal Of Educational And Psychological Researches
The Factorial Structure of The Emotional Intelligence Scale to Bar-On Applied on Students from Preparatory School in Baghdad City.
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The aim of the study was to know the factors analysis of scale Bar-On & Parker, post analysis is found fourteen factors for the first degree of the scale. Also we extracted five factors from the second degree.

  The scale consists of (60) items , applied on sample of (200) students (Male &Female ) age (15-18) years randomly chosen from preparatory schools . The scale unveiled satis factors  validity and reliability. An others aims is to low the  emotional  Intelligence level and  know the difference of statistical in sex , age variable and the specialization variable .The result was no difference of statistical in sex and specialization variable , but the difference appear

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Publication Date
Sun Nov 01 2020
Journal Name
Journal Of Engineering
Nonlinear Finite Element Analysis of RCMD Beams with Large Circular Opening Strengthened with CFRP Material
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This paper presents the non-linear finite element method to study the behavior of four reinforced rectangular concrete MD beams with web circular openings tested under two-point load. The numerical finite elements methods have been used in a much more practical way to achieve approximate solutions for more complex problems.  The ABAQUS /CAE is chosen to explore the behavior of MD beams. This paper also studies, the effect of both size and shape of the circular apertures of MD beams. The strengthening technique that used in this paper is externally strengthening using CFRP around the opening in the MD beams. The numerical results were compared to the experimental results in terms of ultimate load failure and displace

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