Preferred Language
Articles
/
jih-1429
Using The Ultrasonic Waves For Studying Thermal And Elastic Properties as a Function of Porosity in Sintered ceramic
...Show More Authors

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.

View Publication Preview PDF
Quick Preview PDF
Publication Date
Sun Mar 05 2017
Journal Name
Baghdad Science Journal
Studying the effective of conductor polymer substrate on the electrical properties of semiconductors
...Show More Authors

This research includes depositionof thin film of semiconductor, CdSe by vaccum evaporation on conductor polymers substrate to the poly aniline where, the polymer deposition on the glass substrats by polymerization oxidation tests polymeric films and studied the structural and optical properties through it,s IR and UV-Vis , XRD addition to thin film CdSe, on of the glass substrate and on the substrate of polymer poly-aniline and when XRD tests was observed to improve the properties of synthetic tests as well as the semiconductor Hall effect proved to improve the electrical properties significantly

View Publication Preview PDF
Scopus (2)
Scopus Crossref
Publication Date
Tue Oct 01 2019
Journal Name
Journal Of Economics And Administrative Sciences
Using dickey _ fuller expanded test for testing variables of investment function in Iraq
...Show More Authors

         To ascertain the stability or instability of time series, three versions of the model proposed by Dickie-Voller were used in this paper. The aim of this study is to explain the extent of the impact of some economic variables such as the supply of money, gross domestic product, national income, after reaching the stability of these variables. The results show that the variable money supply, the GDP variable, and the exchange rate variable were all stable at the level of the first difference in the time series. This means that the series is an integrated first-class series. Hence, the gross fixed capital formation variable, the variable national income, and the variable interest rate

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Mar 02 2023
Journal Name
8th Engineering And 2nd International Conference For College Of Engineering – University Of Baghdad: Coec8-2021 Proceedings
Using WO3/AlPO4 as a solid catalyst for the transesterification of waste edible oils
...Show More Authors

AlPO4 catalysts supported with WO3 were prepared by impregnating the catalysts with ammonium metatungstate. The catalysts were checked by X-ray Diffraction (XRD), AFM, and SEM; also, the catalysts analysis was done by X-Ray (EDX). Finally, the N2 adsorption-desorption was used to measure the pore volume and surface area of the catalyst. The prepared catalyst has a surface area of 185.83 m2/g, pore volume of 0.645 cm3/g at a calcination temperature of 500°C for 3 hrs, and particle size of AlPO4 with an average of 35.36 nm. Transesterification of edible oil using WO3/AlPO4 was performed, it was observed that WO3/AlPO4 catalysts give high conversion of edible oil, and this is attributed to the high surface area, smaller particle size, and the

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Dec 01 2021
Journal Name
Baghdad Science Journal
Analytical Solutions for Advanced Functional Differential Equations with Discontinuous Forcing Terms and Studying Their Dynamical Properties
...Show More Authors

This paper aims to find new analytical closed-forms to the  solutions of the nonhomogeneous functional differential equations of the nth order with finite and constants delays and various initial delay conditions in terms of elementary functions using Laplace transform method. As well as, the definition of dynamical systems for ordinary differential equations is used to introduce the definition of dynamical systems for delay differential equations which contain multiple delays with a discussion of their dynamical properties: The exponential stability and strong stability

View Publication Preview PDF
Scopus (1)
Scopus Clarivate Crossref
Publication Date
Sat Mar 31 2018
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Study of the Performance of Paraffin Wax as a Phase Change Material in Packed Bed Thermal Energy Storage System
...Show More Authors

The present work deals with an experimental investigation of charging and discharging processes in thermal storage system using a phase change material PCM. Paraffin wax was used as the PCM which is formed in spherical capsules and packed in a cylindrical packed column which acted as an energy storage system. Air was used as the heat transfer fluid HTF in thermal storage unit. The effect of flow rate and inlet temperature of HTF on the time of charging and discharging process were studied. The results showed that the faster storage of thermal energy can be made by high flow rate of heat transfer fluid HTF and high inlet temperature of heat transfer fluid. It was found that at 65°C HTF inlet temperature, the melting and solidification pr

... Show More
View Publication
Publication Date
Sat Dec 01 2018
Journal Name
Journal Of Economics And Administrative Sciences
(Estimation and Analysis of the Cobb-Duglas Production Function for the Rail Transport Sector in Iraq for the Period 1990-2016 using the ARDL Model)
...Show More Authors

Abstract:

Since the railway transport sector is very important in many countries of the world, we have tried through this research to study the production function of this sector and to indicate the level of productivity under which it operates.

It was found through the estimation and analysis of the production function Kub - Duglas that the railway transport sector in Iraq suffers from a decline in the level of productivity, which was reflected in the deterioration of the level of services provided for the transport of passengers and goods. This led to the loss of the sector of importance in supporting the national economy and the reluctance of most passengers an

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue May 01 2012
Journal Name
Iraqi Journal Of Physics
Studying the effect of temperature and treating time on some physical properties of carbon black
...Show More Authors

Samples prepared by using carbon black as a filler material and phenolic resin as a binder. The samples were pressed in a (3) cm diameter cylindrical die to (250)MPa and treated thermally within temperature range of (600-1000)oC for two and three hours. Physical properties tests were performed, like density, porosity, and X-ray tests. Moreover vicker microhardness and electric resistivity tests were done. From the results, it can be concluded that density was increased while porosity was decreased gradually with increasing temperature and treating time. In microhardness test, it found that more temperature and treating time cause more hardness. Finally the resistivity was decreased in steps with temperature and treating time. It can be c

... Show More
View Publication Preview PDF
Publication Date
Fri Sep 15 2023
Journal Name
Journal Of Optics
Studying of the structural and optical properties of titanium dioxide nanoparticles prepared by chemical method
...Show More Authors

View Publication
Scopus (5)
Crossref (2)
Scopus Clarivate Crossref
Publication Date
Sat Mar 18 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Studying the Effect of Annealing Temperature on Structural and Optical Properties of ZnSe Thin Films
...Show More Authors

 The effect of thermal annealing on some structural and optical  properties of ZnSe thin films was studied which prepared by thermal evaporation method with (550±20) nm thickness and annealing at (373,473)K for (2h), By using X-ray diffraction technique structural properties studied and showed that the films are crystalline nature and have ( cubic structure ) .From the observed results after heating treatment, We found that the annealing to perform decreases in grain size and increases in dislocation and observed the optical properties increase in absorption and decrease in transmission. From absorption spectra optical energy gap calculated about (2.66,2.68)eV which decreases value after heating treatment

View Publication Preview PDF
Publication Date
Wed Sep 01 2010
Journal Name
Journal Of Economics And Administrative Sciences
Using simulation to estimate parameters and reliability function for extreme value distribution
...Show More Authors

   This study includes Estimating scale parameter, location parameter  and reliability function  for Extreme Value (EXV) distribution by two methods, namely: -
- Maximum Likelihood Method (MLE).
- Probability Weighted Moments Method (PWM).

 Used simulations to generate the required samples to estimate the parameters and reliability function of different sizes(n=10,25,50,100) , and give real values for the parameters are and , replicate the simulation experiments (RP=1000)

... Show More
View Publication Preview PDF
Crossref