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Free Convective Heat Transfer with Different Sections Lengths Placed at the Exit of a Vertical Circular Tube subjected to a Constant Heat Flux
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A free convective heat transfer from the inside surface of a uniformly heated vertical circular tube has been experimentally investigated under a constant wall heat flux boundary condition for laminar air flow in the ranges of RaL from 6.9108 to 5109. The effect of the different sections (restrictions) lengths placed at the exit of the heated tube on the surface temperature distribution, the local and average heat transfer coefficients were examined. The experimental apparatus consists of aluminum circular tube with 900 mm length and 30 mm inside diameter (L/D=30). The exit sections (restrictions) were included circular tubes having the same inside diameter as the heated tube but with different lengths of 600 mm (L/D=20), 900 mm (L/D=30), 1200 mm (L/D=40), 1500 mm (L/D=50), and 1800 mm (L/D=60). It was found that the surface temperature along the tube axial distance would be higher for restriction with length of 1800 mm (L/D=60) and it would be smaller for the restriction with length of 1200 mm (L/D=40). The results show that the local Nux and average Nusselt number were higher values for the restriction with length of 1200 mm (L/D=40) and smaller values for the restriction with length of 1800 mm (L/D=60). The results were correlated with empirical equations and presented as Logagainst Log for each case investigated and a general empirical equation was proposed for all cases.

 

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Publication Date
Thu Jun 04 2026
Journal Name
Journal Of Baghdad College Of Dentistry
Evaluation of transverse and tensile bond strength of repaired nylon denture base material by heat, cold and visible light cure acrylic resin
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Background: Denture fracture is one of the most common problems encountered by the patients and prosthodontists. The objective of present study was to evaluate the transverse strength of nylon denture base resin repaired by using conventional heat polymerized, autopolymerized and visible light cure {VLC} resins, surface treatment that used for repair and adjustment of insufficient nylon denture bases and in case of addition of artificial teeth. As these corrective procedures are common chair side procedures in dental clinic. Materials and methods: One hundred twenty nylon specimens were prepared by using metal patterns with dimension of (65x10x2.5 mm) length, width, and thickness respectively for transverse strength test while for tensile b

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Publication Date
Sun Jul 17 2022
Journal Name
Al–bahith Al–a'alami
Post-interactive communication A study to build a model for the flow of communication in social networking sites
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The issue of the research lies in the non-representation of the models developed for the communication process in the interaction and networking processes through social media, as the research sought to build a network model of communication according to the specific data and features of social media platforms in order to reach a special generalization to understand how the process of networking operates in cyberspace.

The researcher followed the analytical survey approach as she described the communication models outwardly in order to be able to build a networked communication model that represents the flow of post-reactive communication. Therefore, it has been named "Nebula - Sadeem" after the concept of post-space and cosmic g

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Publication Date
Tue Sep 17 2019
Journal Name
Journal Of The College Of Education For Women
A New Logic of Victory in Suzanne Collins’ The Hunger Games With Reference to Elements of Intertextuality in William Golding’s Lord of the Flies
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Suzanne Collins’ novel  The Hunger Games suggests a new logic of victory and set a distinguished focus on the unique personality of her heroin which brings to the mind the permanent correlation between all moral values. The Hunger Games World seems to be much more like one big bowl as it links the past, present, and the future. An Intertextual reference is interwoven in the present research as it brings Golding’s Lord of the Flies to the surface, and it highlights certain similarities between the two texts. In which Ralph, Piggy and Simon in Golding’s Lord of the Flies are the incarnations of stable moral values and hope of surviving ethics and rules in a chaotic and turmoil world. The event

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
The Role Of Smart Leadership Dimensions In Crisis Management- A study For Opinions Of Sample Of Administrative Leaderships In A number Of Humanities Colleges At The University Of Mosul
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This research aims at answering many questions raised by the research problem concerning the view of the organizations under consideration for the concept of smart leadership and its most important dimensions, as well as the view of crisis management and its concept and most important methods through research objectives that define and clarify the smart leadership with its dimensions and methods of crisis management.

For the purpose of reaching the results of the research and testing the assumptions about the relationship between smart leadership and methods of crisis management, the researcher adopted a questionnaire, designed especially to be a criterion for the research, as the main tool for data coll

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Publication Date
Wed Apr 27 2022
Journal Name
Arabian Journal For Science And Engineering
Optical and Thermal Performance of a Parabolic Trough Collector for Different Receiver Geometries
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This paper numerically and theoretically investigates the optical and thermal performance of a parabolic trough collector PTC system. Many numerical simulations and theoretical analyses are conducted to demonstrate the influence of the receiver geometry and shifting from the focal position on the optical performance. The examined receiver geometries are circular, square, triangular, elliptical, and the new circular–square combined geometry is named as channel receiver. The thermal performance of PTC is examined for different volume flow rates theoretically in the range of (0.36 to 2.4 lpm). The results show that the best optical design is the channel receiver with an intercept factor of 84%, while the worst is the elliptical receiver with

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Publication Date
Fri Dec 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Office managers skills and it's impact on the effectiveness of time management A survey of a sample of departments managers in the institutes and faculties at the middle technical university
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The objective of this study is to highlight the skills of office managers and it's impact on the effectiveness of time management in the institutes and faculties of middle technical university and a group of cognitive and practical aims. The managers skills forms mthe modern trend and the main source to provide organizations with highly skilled managers with distinctive performance and because of the sharp changes in the environment which today's organizations works in it , business organizations generally and managers especially realise the importance of time management and it's role in achieving competitive advantage . The problem of this study raised from this point which reflect the extent of departments managers realisation

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Publication Date
Fri Nov 24 2017
Journal Name
Journal Of Engineering
A new analytic method to tune a fractional order PID controller
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This paper proposes a new method to tune a fractional order PID controller. This method utilizes both the analytic and numeric approach to determine the controller parameters. The control design specifications that must be achieved by the control system are gain crossover frequency, phase margin, and peak magnitude at the resonant frequency, where the latter is a new design specification suggested by this paper. These specifications results in three equations in five unknown variables. Assuming that certain relations exist between two variables and discretizing one of them, a performance index can be evaluated and the optimal controller parameters that minimize this performance index are selected. As a case study, a third order linear time

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Publication Date
Fri Nov 24 2017
Journal Name
Journal Of Engineering
A New Analytic Method to Tune a Fractional Order PID Controller
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This paper proposes a new method to tune a fractional order PID controller. This method utilizes both the analytic and numeric approach to determine the controller parameters. The control design specifications that must be achieved by the control system are gain crossover frequency, phase margin, and peak magnitude at the resonant frequency, where the latter is a new design specification suggested by this paper. These specifications results in three equations in five unknown variables. Assuming that certain relations exist between two variables and discretizing one of them, a performance index can be evaluated and the optimal controller parameters that minimize this performance index are selected. As a case study, a thir

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Publication Date
Sun Dec 27 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Evaluation the profitability of public commercial banks using liquidity indicators: A comparison of the Rafidain and Rasheed study
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The issue of liquidity, profitability, and money employment, and capital fullness is one of the most important issues that gained high consideration by other authors and researchers in their attempts to find out the real relationship and how can balance be achieved, which is the main goal of each deposits.

For the sake of comprising the study variables, the research has formed the problem of the study which refers to the bank capability to enlarge profits without dissipation in liquidity   of the bank which will negatively reflect on the bank's fame as well as the customers' trust. For all these matters, the researcher has proposed a set of aims, the important of which is the estimation of the bank profitability; liquid

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Publication Date
Tue Aug 15 2023
Journal Name
Sumer 1
The effect of silver diamine fluoride on the microleakage of glass ionomer restoration in primary teeth at different time intervals
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Silver diamine fluoride (SDF) has shown effectiveness in hardening tooth structure and killing bacteria. Therefore, it can be used to prevent and arrest dental caries. Riva Star (SDF) treatment alone will stop cavities but will not reverse the cavitation. The Silver Modified Atraumatic Procedure, often known as Smart, is the optimum technique for regaining the tooth's structure and function. Glass ionomer was introduced in (1972) as a new material that has become one of the most widely used materials in restorative dentistry. By releasing fluoride ions, this material has a therapeutic impact on the surrounding tooth structure. Microleakage is the ingress of bacteria, its byproducts, toxins, chemicals, oral fluids, and ions between t

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