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jih-1429
Using The Ultrasonic Waves For Studying Thermal And Elastic Properties as a Function of Porosity in Sintered ceramic
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Ultrasonic pulse echo measurements on porous alumina as ceramic

material with porosities ranging from (20-40)% showed effect of volume

fraction of porosity on both thermal and elastic properties. A quadratic relationships, by using a least squares method, is deduced for the dependence of the shear velocity, longitudinal velocity, shear modulus, Young's modulus,  bulk  modulus, Poisson 's ratio, Debye temperature, specific heat, and thermal conductivity on the total  porosity. By these relationships,  the  thermal  and  elastic  properties  results  of  pore-free alumina  were  calculated.  The  elastic  properties  results  of  ceramic decrease substantially  with  increasing porosity,  except  Poisson 's  ratio which is the constant. Debye temperature and thermal conductivity decrease too substantially with increase of porosity, while specific heat increases.

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Publication Date
Sat Sep 01 2012
Journal Name
Journal Of Economics And Administrative Sciences
A comparison Of Some Semiparametric Estimators For consumption function Regression
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    This article aims to explore the importance of estimating the a semiparametric regression function ,where we suggest a new estimator beside the other combined estimators and then we make a comparison among them by using simulation technique . Through the simulation results we find  that the suggest estimator is the best with the first and second models ,wherealse for the third model we find Burman and Chaudhuri (B&C) is best.

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Publication Date
Sat Dec 01 2018
Journal Name
Al-khwarizmi Engineering Journal
The Effect of Walled Nano-Carbon on the Physical, Thermal and Mechanical Properties of Epoxy
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The physical, the thermal and the mechanical properties of Nano-composites, that consisted of Polyprime EP epoxy that reinforced by multi-walled carbon nanotubes (MWCNTs), have been studied. Various loading ratios, 0.1, 0.5, and 1 wt. %of MWCNT shave been infused into epoxy by a magnetic stirrer and then the hardener mixed with the mthat supplied with the epoxy. All sample shave been cutting using CNC machine. Tensile test, three-point bending, hardness tests, lee's disk, differential scanning calorimetry, water absorption and dielectric and electrical conductivity test were utilized on unfilled, MWCNT-filled epoxy to identify the loading effect on the properties of materials. Scanning electron microscopy (SEM) was used to determine the

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Publication Date
Thu Jun 04 2020
Journal Name
Journal Of Discrete Mathematical Sciences And Cryptography
User authentication system based specified brain waves
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A security system can be defined as a method of providing a form of protection to any type of data. A sequential process must be performed in most of the security systems in order to achieve good protection. Authentication can be defined as a part of such sequential processes, which is utilized in order to verify the user permission to entree and utilize the system. There are several kinds of methods utilized, including knowledge, and biometric features. The electroencephalograph (EEG) signal is one of the most widely signal used in the bioinformatics field. EEG has five major wave patterns, which are Delta, Theta, Alpha, Beta and Gamma. Every wave has five features which are amplitude, wavelength, period, speed and frequency. The linear

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Publication Date
Sun Mar 07 2010
Journal Name
Baghdad Science Journal
Darwinian Philosophy as Optimization Method for Design High Reflection Mirror Include New Merit Function
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In this paper we proposes the philosophy of the Darwinian selection as synthesis method called Genetic algorithm ( GA ), and include new merit function with simple form then its uses in other works for designing one of the kinds of multilayer optical filters called high reflection mirror. Here we intend to investigate solutions for many practical problems. This work appears designed high reflection mirror that have good performance with reduction the number of layers, which can enable one to controlling the errors effect of the thickness layers on the final product, where in this work we can yield such a solution in a very shorter time by controlling the length of the chromosome and optimal genetic operators . Res

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Publication Date
Thu Jul 01 2021
Journal Name
Solar Energy
A new approach for employing multiple PCMs in the passive thermal management of photovoltaic modules
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Publication Date
Mon Jun 09 2025
Journal Name
Journal Of Baghdad College Of Dentistry
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 c

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Publication Date
Mon May 22 2023
Journal Name
Proceedings Of The 1st International Conference On Frontier Of Digital Technology Towards A Sustainable Society
Effect of thermal annealing on the structural and optical properties of Sb2Se3 thin films
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In this paper the effect of thermal annealing on the structural and optical properties of Antimony Selenide (Sb2Se3) is investigated. Sb2Se3 powder is evaporated on clean amorphous glass substrates at room temperature under high vacuum pressure (4.5×10-6 mbar) to form thin films. The structural investigation was done with the aid of X-ray diffraction (XRD) and atomic force microscopy (AFM). The amorphous to polycrystalline transformation of these thin films was shown by X-ray diffraction analysis after thermal annealing. These films' morphology is explained. (UV-Vis ) spectra in ranges from 300 to 1100 nm was used to examine the optical properties of the films .The absorption coefficient and optical energy gap of the investigated films are

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Publication Date
Fri Jun 30 2017
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Effect of Kaolinite on the Mechanical Properties, Thermal Properties, Flammability and Water Absorption Percentage of Poly (Vinyl Chloride) Composite
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PVC/Kaolinite composites were prepared by the melt intercalation method. Mechanical properties, thermal properties, flammability and water absorption percentage of prepared samples were tested. Mechanical characteristic such as tensile strength, elongation at break; hardness and impact strength (charpy type) were measured for all samples. It was found that the tensile strength and elongation at break of PVC composites decreased with increasing kaolinite loading. Also, the hardness of the composites increases with increase in filler content .The impact strength of the composites at the beginning increases at lower kaolinite loadings is due to the lack of kaolin adhesion to the matrix. However, at higher kaolin loadings. This severe agglom

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Publication Date
Tue Sep 04 2018
Journal Name
Al-khwarizmi Engineering Journal
Studying the Mechanical Properties of Denture Base Materials Fabricated from Polymer Composite Materials
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In this research, the effect of adding two different types of reinforcing particles was investigated, which included: nano-zirconia (nano-ZrO2) particles and micro-lignin particles that were added with different volume fractions of 0.5%, 1%, 1.5% and 2% on the mechanical properties of polymer composite materials. They were prepared in this research, as a complete prosthesis and partial denture base materials was prepared, by using cold cure poly methyl methacrylate (PMMA) resin matrix. The composite specimens in this research consist of two groups according to the types of reinforced particles, were prepared by using casting methods, type (Hand Lay-Up) method. The first group consists of PMMA resin reinforced by (nano-ZrO

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Publication Date
Wed Apr 02 2025
Journal Name
Retos
The effect of rehabilitation exercises accompanied by ultrasound waves in reducing pain and healing from carpal tunnel compression
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Objective: The current study aimed identifying the impact of rehabilitative exercises combined with ultrasonic waves on reducing pain in people with carpal tunnel compression and determining how these activities affect range of motion of the upper limb for those suffering from carpal tunnel compression. Research methodology: With pre- and post-tests, the researchers employed the experimental method in the form of two equal groups, the experimental and the control. The scientific community and sample are among the priorities that fall on the researcher, so The scientific community is determined by those suffering from carpal tunnel compression, numbering (14) patients. (12) Patients were approved and two were excluded from the resear

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