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Free Convection in an Inclined Concentric Annular Square Cavities Filled With Porous Medium and Heated By Non-Uniform Temperature
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A numerical study of the two-dimensional steady free convection flow in an inclined annulus between two concentric square cavities filled with a porous medium is presented in this paper for the case when the side outer walls are kept with differentially heated temperature while the horizontal outer walls and the inner walls are insulated. The heated wall is assumed to have spatial sinusoidal temperature variation about a constant mean value. The Darcy model is used and the fluid is assumed to be a standard Boussinesq fluid. For the Cartesian coordinate system, the governing equations which were used in stream function form are discretized by using the finite difference method with successive under – relaxation method (SUR) and are solved by Gauss-Siedel iterative method. The upwind scheme was used for the transport terms in the energy conservation equation. The results are presented to demonstrate the streamlines, the isotherms, and the Nusselt number depending on the Rayleigh number ranging from (Ra =10 to 1000), dimension ratio from (Dr = 0.15 to 0.45), and the inclination angle from (= 0o to 45o). Also the effects of the amplitude (=0 to 1) and the wave number (f =0 to 5) of the heated side wall temperature variation on the free convection are investigated. The results show the effect of previous parameters (Ra, Dr,, , and f) on the flow fields and temperature profiles. It also show that the average Nusselt number is a strong function of the Rayleigh number, inclination angle, dimension ratio, and temperature variation. The peak value of the average Nusselt number based on the hot wall temperature is observed to occur at dimension ratio of (0.15), inclination angle of (40.1°), amplitude and wave  number (1 & 0.75) for Rayleigh number of (1000).

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Publication Date
Mon Sep 30 2024
Journal Name
Joiv : International Journal On Informatics Visualization
Evaluation of the Performance of Kernel Non-parametric Regression and Ordinary Least Squares Regression
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Researchers need to understand the differences between parametric and nonparametric regression models and how they work with available information about the relationship between response and explanatory variables and the distribution of random errors. This paper proposes a new nonparametric regression function for the kernel and employs it with the Nadaraya-Watson kernel estimator method and the Gaussian kernel function. The proposed kernel function (AMS) is then compared to the Gaussian kernel and the traditional parametric method, the ordinary least squares method (OLS). The objective of this study is to examine the effectiveness of nonparametric regression and identify the best-performing model when employing the Nadaraya-Watson

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Publication Date
Tue Feb 21 2017
Journal Name
Biomechanics And Modeling In Mechanobiology
A novel method for non-invasively detecting the severity and location of aortic aneurysms
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The influence of an aortic aneurysm on blood flow waveforms is well established, but how to exploit this link for diagnostic purposes still remains challenging. This work uses a combination of experimental and computational modelling to study how aneurysms of various size affect the waveforms. Experimental studies are carried out on fusiform-type aneurysm models, and a comparison of results with those from a one-dimensional fluid–structure interaction model shows close agreement. Further mathematical analysis of these results allows the definition of several indicators that characterize the impact of an aneurysm on waveforms. These indicators are then further studied in a computational model of a systemic blood flow network. This demonstr

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Publication Date
Tue Jan 01 2019
Journal Name
Journal Of Global Pharma Technology
Analytical Study for the Ability of Some Polymers to Gain Transitional Elements Ionsions in Different Temperature, PH Acidity Functional and Time Situations
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The compound [K1] was synthesized from the reaction of dichloromethane with linear alkyl benzene (Lab9) using ethanol as a solvent, and from(chloro methyl)-4-nonylbenzene) [K1] it was possible to synthesize the compound Z(4-(nonan-3-yl)phenyl) methane amine) [K2] containing the amine group by synthesized from [K2] reaction with appropriate phenolic aldehydes and using Ethanol as a solvent in the preparation of vinyl chloride4-(((4-nonylbenzyl)imino)methyl)phenol-4-(((4-nonylbenzyl)imino methyl)benzene-1,3diol) [K3-K4] bases has been used. Preparation of a number of Phenolic polymers4-(2- hydroxy-3.5-dimethylbenzyl)-2-methyl-6-(((4-4-(2hyroxy-3, 5-dimethylbenzyl)-2-methyl-6(((4 nonylbenzyl) imino) methyl) benzene-phenolnonylbenzyl) imino) me

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Publication Date
Fri Jan 01 2021
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Measuring the relationship between the skills required for the labor market and the employment of graduates of community colleges in KSA: An applied study on a sample of faculty members at KKU
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This study has aimed to measure the relationship between the skills required for the labor market and the employment of graduates of community colleges at King Khalid University. For gathering the required data, a questionnaire has been designed and distributed to the faculty members of community colleges at King Khalid University in a random sample method. The chosen sample size has covered (123) individuals. Questionnaire forms have been distributed and retrieved from (117) participants. Therefore, the estimated response has reached 95 % of the total sample size. The results of the study have shown that there is not any significant relationship between the skills which the graduates   acquire and the requirements of employmen

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Publication Date
Sat Sep 01 2007
Journal Name
Journal Of Economics And Administrative Sciences
Comparison Between Ordinary Method and Robust Method to estimate the Parameters of the Univariate Mixed Model with Low Order
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A condense study was done to compare between the ordinary estimators. In particular the maximum likelihood estimator and the robust estimator, to estimate the parameters of the mixed model of order one, namely ARMA(1,1) model.

Simulation study was done for a varieties the model.  using: small, moderate and large sample sizes, were some new results were obtained. MAPE was used as a statistical criterion for comparison.

 

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Publication Date
Mon May 13 2024
Journal Name
Journal Of Engineering And Applied Science
Assessment of using different ozone-friendly R22 alternative refrigerants in residential air conditioners in a high-ambient temperature country
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Abstract<p>The performance of a vapor compression refrigeration system (VCRS)-based residential air conditioner operating in a high-ambient temperature (HAT) country was investigated using six zero-ODP (ozone depletion potential) refrigerants as replacements to R22. The non-flammable alternative refrigerants considered in the present research were R134a, R404A, R407C, R410A, R448A, and R507A. Using the basic conservation laws, the VCRS was modeled during steady-state operation and solved using engineering equation solver (EES) software. Coefficient of performance (COP), pressures and temperatures at compressor suction and discharge, Global Warming Potential (GWP), critical pressure and temperature, compressor </p> ... Show More
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Publication Date
Tue Jun 01 2021
Journal Name
Political Sciences Journal
The security environment in Northeast Asia between American authority and Chinese influence
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The security environment for Northeast Asia is extremely important, as it includes most of the international actors (United States of America, China, Russian Federation and Japan), which gives the nature of the interactions of these forces a special importance for the region.

Because of the multiplicity of policies and interests of the active forces in the region, the result has been an unstable regional environment where the interests of the major powers often clash repeatedly on many related issues, which is coupled with the growing efforts of many powers to adopt policies that differ from what they did in the past This resulted in different patterns of relations, which were mainly characterized by competition over regional lea

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Publication Date
Wed Nov 01 2017
Journal Name
Journal Of Economics And Administrative Sciences
Applied Study on Analysis of Fixed, Random and Mixed Panel Data Models Measured at specific time intervals
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This research sought to present a concept of cross-sectional data models,  A crucial double data to take the impact of the change in time and obtained from the measured phenomenon of repeated observations in different time periods, Where the models of the panel  data were defined by different types of fixed , random and mixed, and Comparing them by studying and analyzing the mathematical relationship between the influence of time with a set of basic variables Which are the main axes on which the research is based and is represented by the monthly revenue of the working individual and the profits it generates, which represents the variable response And its relationship to a set of explanatory variables represented by the

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Publication Date
Sat May 01 2021
Journal Name
Key Engineering Materials
The Effect of Temperature Width on Dielectric Constant of Vanadium Dioxide
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A significant influence of temperature width found on the vanadium oxide properties, it plays a major role in highlighting the thermal limits of the three phases (metallic, semiconductor, and dielectric). Two values of the temperature width , and , had taken and studied their effect on both the dielectric constant and its two parts; refractive index, and extinction coefficient, and. It found that: as the temperature width is greater, the more the properties of the three phases for . In addition to increasing the thermal range for phases which can be reached to when , while it's at . Our results have achieved great compatibility with the published results globally. In addition to the effect of both ultraviolet, visible, and infrared

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Publication Date
Sun Jun 01 2025
Journal Name
Journal Of Physics: Conference Series
Measuring Urban Heat Island Indicators from Surface Temperature Using Spatial Techniques
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Abstract<p>Using remote sensing technology and modeling methodologies to monitor changes in land surface temperature (LST) and urban heat islands (UHI) has become an essential reference for making decisions on sustainable land use. This study estimates LST and UHI in Salah al-din Province to contribute to land management, Urban planning, or climate resilience in the region; as a result of environmental changes in recent years, LANDSAT Satellite Imagery from 2014- 2024 was implemented to estimate the LST and UHI indexes in Salah al-din Province, ArcGIS 10.7 was use to calculate the indices, and The normalized mean vegetation index (NDVI) was calculated as it is closely related to extracting (LST </p> ... Show More
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