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jih-1427
Dielectric Properties of High Alumina Glass
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High   Alumina   Glasses   "Alumina   Silicate   Glasses"   was prepared by utilizing powder technology technique. The starting materials are wasted soda-lime glass from an industrial site, Iraqi­ Duekhla raw kaolin and small amounts of potassium carbonates.

X-ray Diffraction and FTIR analysis show complete vitreous glasses are obtained. Increasing Alumina content plays an obvious role in improving physical and mechanical properties of the prepared high  alumina  glass.   In  addition,  the   increased  alumina  content enhanced the dielectric constant and reduced dielectric loss. These results may be interpreted as due to the bridging bonding of alumina with  both  the   silica  and  the  alkali  oxides;  which  impedes  the alternating electric field.

 

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Publication Date
Thu May 11 2017
Journal Name
Ibn Al-haitham Journal For Pure And Applied Sciences
Using Gamma Ray Transmission for Determination of Porosity in Doped Alumina Samples
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     In this study, gamma ray transmission method have been used to determine the total porosity in four samples: pure Alumina  ( Al2O3   ),  Al2O3 + (0.2wt%)MgO ,  Al2O3 + (0.6wt% )Y2O3  and Al2O3+ (8wt% ) ZrO2 .

      The experimental setup for the gamma ray transmission consist of 137Cs gamma source ( 662 KeV  ), a  NaI (Tl) scintillation detector measured the attenuation of strongly collimated  gamma beam through alumina samples.

The porosity obtained by the gamma ray transmission method were compare

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Publication Date
Fri Oct 01 2010
Journal Name
Iraqi Journal Of Physics
Mechanical Strength of Alumina Compacts Lubricated with Poly (methacrylic acid esters) Copolymers
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In recent years, there has been a rapid development in research on high performance ceramics for mechanical, electrical and medical industries. This development will be shown for alumina as a representative for oxide ceramics powders.
Dry–pressing forming technique was used to prepare different ceramic compacts for alumina grafted by polymethacrylate polymers. All Alumina compact were fired firstly at 1200 ◌ْ C, then
at 1600 ◌ْ C.
Mechanical strength was examined in different means, some
depends on compression and other depends on impact. Hardness was
also measured .The results obtained were compared with that of
Alumina compact prepared under the same condition from Alumina
especially made for pressing .

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Publication Date
Sun Dec 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of Photo-Initiated Oxidation on Mechanical Properties of High Density Polyethylene / Linear Low Density Polyethylene Blends
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The long – term behaviour of polyethylene products used out doors is affected by weathering. In the present work,
weathering test was carried out to find the effect of the environment conditions on the mechanical properties of
HDPE/LLDPE blends with different weight percents (0, 15, 30, and 45 %) relative to the LLDPE by increasing the
exposure times to (100, 150, 200, 250, 300) hr.
A series of tests (destructive), tensile, impact and hardness were carried out on the prepared samples, the results
obtained declare the changes on the material behaviour from ductile to brittle and the polymer shows a decline in the
mechanical properties with increasing the exposure times.
In the present work empirical equations were r

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Publication Date
Mon Dec 11 2017
Journal Name
Al-khwarizmi Engineering Journal
The Effects of Long-Term Operation and High Temperature on Material Properties of Austenitic Stainless Steel Type 321H
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Changes in mechanical properties of material as a result of service in different conditions can be provided by mechanical testing to assist the estimation of current internal situation of these materials, or the degree of deterioration may exist in furnaces serviced at high temperature and exceed their design life. Because of the rarity works on austenitic stainless steel material type AISI 321H, in this work, ultimate tensile strength, yield strength, elongation, hardness, and absorbed energy by impact are evaluated based on experimental data obtained from mechanical testing. Samples of tubes are extracted from furnace belong to hydrotreaterunit, also samples from un-used tube material are used to make comparisons between these properti

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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
Sat May 01 2021
Journal Name
Journal Of Physics: Conference Series
The effect of heat treatment on structure property of (Bentonite - Alumina - Silica) Ceramic
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Abstract<p>In this work, a ceramic model has obtained from Iraqi bentonite as a base material with limited additions of alumina and silica. The selected material can bear temperatures higher than the bearing temperature of bentonite as it achieved tolerance temperatures (1300°C) based on X-ray diffraction patterns. It was found that the addition of alumina and silica led to the occurrence of basic phases such as mullite, quartz, cordierite and feldspar in percentages that depended on the percentage of addition in the mixture and the firing temperature, which was (1000-1300)°C.</p>
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Publication Date
Wed Dec 01 2010
Journal Name
Iraqi Journal Of Physics
Effect of Furnace Vacuum Pressure on the Joining Strength of Alumina Bonded Kovar
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Ceramic to metal joining technique, which was used in this investigation includes the use of active filler alloy as a sandwich between the alumina and kovar alloy for brazing. High purity powdered metals of silver, copper, and additives of titanium were used to prepare the active filler alloy, through compacting the mixed powders and alloying in a furnace with argon atmosphere at the temperature of 800oC for 10 minutes. To use it as an active filler metal, it has been modified to a proper thickness. Two groups of alumina were prepared with different sintering temperatures (1450oC and 1650oC) and each group was tested under atmospheric pressure, vacuum furnace pressure of 2*10-4 torr and vacuum furnace pressure of 2*10-6 torr. All the pro

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Publication Date
Tue Sep 30 2014
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
Study the Feasibility of Alumina for the Adsorption of Metal Ions from Water
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The present work describes the adsorption of Ba2+ and Mg2+ions from aqueous solutions by activated alumina in single and binary system using batch adsorption. The effect of different parameters such as amount of alumina, concentration of metal ions, pH of solution, contact time and agitation speed on the adsorption process was studied. The optimum adsorbent dosage was found to be 0.5 g and 1.5 g for removal of Ba2+ and Mg2+, respectively. The optimum pH, contact time and agitation speed, were found to be pH 6, 2h and 300 rpm, respectively, for removal of both metal ions. The equilibrium data were analyzed by Langmuir and Freundlich isotherm models and the data fitted well to both isotherm modes as indicated by higher correlation of deter

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Publication Date
Sun Jun 05 2011
Journal Name
Baghdad Science Journal
Correlation between Paris function parameters to crack velocity for Alumina ceramics
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The question about the existence of correlation between the parameters A and m of the Paris function is re-examined theoretically for brittle material such as alumina ceramic (Al2O3) with different grain size. Investigation about existence of the exponential function which fit a good approximation to the majority of experimental data of crack velocity versus stress intensity factor diagram. The rate theory of crack growth was applied for data of alumina ceramics samples in region I and making use of the values of the exponential function parameters the crack growth rate theory parameters were estimated.

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Publication Date
Wed Jan 02 2019
Journal Name
Pramana
The description of quantum dielectric function for insulators over Bethe surface
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