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The Effect of Ceramic Thickness and Number of Firings on the Color of Two All-Ceramic Systems Measured by Spectrophotometer
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Background: This in vitro study was carried out to evaluate the effects of various veneering dentin ceramic thicknesses and repeated firings on the color of lithium disilicate glass-ceramic (IPS e.max Press) and zirconium-oxide (IPS ZirCAD) all-ceramic systems, measured by clinical spectrophotometers (Easyshade Advance 4.0) . Materials and methods: The 72specimens cube-shaped have the dimension of about 11 mm in width, 14 mm in length, 1mm in thickness, these cores divided into 3 groups according to the type of material each group have (24)core specimens. Each group had been divided into three sub-groups (each having 8 specimens) according to veneering with dentin ceramic thicknesses: as 0.5, 1, or 2 mm (n=8). IPS e.max press and ZirCAD cores group had been veneered with IPS e.max Ceram dentin ceramic shade A2 according to manufacturer’s instructions and the metal group had been veneered with IPS classic dentine ceramic with shade A2 according to manufacturer’s instructions. Repeat firings (3, 5 and 7 times) had been applied on all the specimens. Color differences among ceramic specimens had been measured using a clinical spectrophotometer (VITA Easyshade); the color data had been expressed according the Vita Classic shade guide. Results: The shade of all specimens had been compared inside the subgroups and with the main groups. The percentage of color agreement among the subgroups showed the color of all ceramic systems had been affecting by firing interval, the ceramic thickness and brand of ceramic. The number firings intervals applied on the all ceramic system has a significant effect on the final color, the increase of firing number change the color to a darker and reddish color. The 5th firing interval is the point at which the major color changes happened (darker shade), and in next interval (7th firing) less color changes happened. The thickness of veneering ceramic affected the color significantly. The 0.5 mm specimens in all groups showed the highest percentage of agreement (less color changes) after firing intervals, then the 1mm came and the least percentage of agreement ( highest color changes ) was the 2 mm specimens. The Brand of veneering ceramic and the type of core record a significance difference in color changes when exposed to firing heat. Conclusion: With limit of this study, the final color of the all ceramic system definitely affected by the number of firing cycle exposed to, and the veneering ceramic thickness have a clear effect on the final shade of the all ceramic tested.

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Publication Date
Wed Feb 02 2022
Journal Name
Journal Of Physics: Conference Series
Studying the parameters effect of the sputtering yield for polypropylene bombarding by ions of atmospheric background gases
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Publication Date
Tue Dec 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
The Effect of Administrative Accounting Functions on the Practices of the Higher and Central Administrations of the Economic Unit "An Applied Study on Joint Stock Companies"
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Strategy Descrtibes How an Organization Matches its own Capabilites With Opportunities in Environment , in Order to Accomplish its Overall Objectives , So That The Organization is Considering Responding to Challenges by Adopting one or More of Strategies, Like Differentioning its Product, or Achieving Cost Leadership.

The Key Role of Management Accountant is to Evlaute The Successful it Has Been in Implementing Organization Strategy.

This Research Target to Explain The Key Role of Management Accountant in Evaluate of  Organization Strategy. by Strategic Analysis of Operating Income From Specific Sources Such as Cost Savings and Growth in Stead of Emphasizing Only The Aggrega

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Publication Date
Tue Sep 01 2015
Journal Name
Journal Of Engineering
Experimental Study on the Effect of Using Metallic Brushes on the Charging and Discharging Time of Thermal Energy Storage Unit
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Phase change materials are known to be good in use in latent heat thermal energy storage (LHTES) systems, but one of their drawbacks is the slow melting and solidification processes. So that, in this work, enhancing heat transfer of phase change material is studied experimentally for in charging and discharging processes by the addition of high thermal conductive material such as copper in the form of brushes, which were added in both PCM and air sides. The additions of brushes have been carried out with different void fractions (97%, 94% and 90%) and the effect of four different air velocities was tested. The results indicate that the minimum brush void fraction gave the maximum heat transfer in PCM and reduced the time

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Publication Date
Tue Dec 01 2009
Journal Name
Journal Of Economics And Administrative Sciences
Analysis of the theoretical framework of the REA accounting model Used in the design of accounting information systems
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Researchers often equate database accounting models in general and the Resources-Events-Agents (REA) accounting model in particular with events accounting as proposed by Sorter (1969). In fact, REA accounting, database accounting, and events accounting are very different. Because REA accounting has become a popular topic in AIS research, it is important to agree on exactly what is meant by certain ideas, both in concept and in historical origin. This article clarifies the analyzing framework of REA accounting model and highlights the differences between the terms events accounting, database accounting, semantically-modeled accounting, and REA accounting. It als

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Publication Date
Tue Dec 29 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
The role of the external auditor in assessing the security of information technology systems in light of (ISO/IEC 27001): (Applied research on a sample of private banks)
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This research aims to shed light on the necessity of establishing an information security management system through which banking security risks are managed in the light of the ISO (IEC 27001) standard, through which bank departments seek to demonstrate the management of their security systems and their controls in accordance with the specifications of the standard to obtain an internationally recognized security certificate And the need for senior management in banks to an independent person with scientific and practical qualification and who has accredited certificates in the field of information technology for the purpose of helping them to verify the level of compatibility between the policies and procedures applied and the p

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Publication Date
Sat Jan 01 2022
Journal Name
Communications In Mathematical Biology And Neuroscience
A careful study of the effect of the infectious diseases and refuge on the dynamical behavior of prey-scavenger modeling
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In this paper, the dynamics of scavenger species predation of both susceptible and infected prey at different rates with prey refuge is mathematically proposed and studied. It is supposed that the disease was spread by direct contact between susceptible prey with infected prey described by Holling type-II infection function. The existence, uniqueness, and boundedness of the solution are investigated. The stability constraints of all equilibrium points are determined. In addition to establishing some sufficient conditions for global stability of them by using suitable Lyapunov functions. Finally, these theoretical results are shown and verified with numerical simulations.

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Publication Date
Tue Jan 01 2019
Journal Name
Aip Conference Proceedings
Study the effect of addition of Ar to N2 gas on the EEDF and the correspondent coefficients of electron transport
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Publication Date
Wed Dec 01 2010
Journal Name
Iraqi Journal Of Physics
The effect of annealing and the influence of Gamma-ray on the optical properties of nanostructure Zinc Oxide Thin Films
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The semiconductor ZnO is one of II – VI compound group, it is prepare as thin films by using chemical spray pyrolysis technique; the films are deposited onto glass substrate at 450 °C by using aqueous zinc chloride as a spray solution of molar concentration 0.1 M/L. Sample of the prepared film is irradiating by Gamma ray using CS 137, other sample is annealed at 550°C. The structure of the irradiated and annealed films are analyzed with X-ray diffraction, the results show that the films are polycrystalline in nature with preferred (002) orientation. The general morphology of ZnO films are imaged by using the Atomic Force Microscope (AFM), it constructed from nanostructure with dimensions in order of 77 nm.
The optical properties o

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Publication Date
Sat Mar 27 2021
Journal Name
مجلة دراسات ويحوث التربية الرياضية
Hypoxic exercises by using (training mask) and its effect on the (PMA) and some physiological indicators and achievement for 1500m runners
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Hypoxic training, which in turn is one of the methods adopted in sports training methods, especially in activities that depend on the aerobic system in its performance, which includes training with a lack of oxygen by reducing its molecular pressure, since this method targets functional organs and works temporary responses during training and permanent responses After training as an adaptation to these devices as a result of training in this way, the study aimed to identify the effect of hypoxic exercises using the training mask and the extent of the change in some biochemical indicators, in addition to that to identify the effect of these exercises on the indicator of energy expenditure and )VMA) and the achievement of the effectiveness of

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Publication Date
Wed Mar 30 2022
Journal Name
Journal Of Economics And Administrative Sciences
Internal Debt Options during the Two Double Shocks and Its Impact on Foreign Reserve in Iraq
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The research aims at a statement Internal Debt options during shocks and the impact of this borrowing in the volume of the foreign reserve, using induction and deduction with available data analysis. During the period (2004-2013) did not require the use of borrowing across (financial institutions, discounted transfers, bonds); it was only sufficient by transfer with commercial banks that can finance of temporary budget deficits: rose and decline of volume of foreign reserve according to the changes of oil prices and the volume of purchases and sales of the Central Bank of Iraq. Central Bank of Iraq (CBI) has significantly contributed to Internal Debt through bond and discounted transfers in the secondary market; thus, funding the

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