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Electrical and Optical Properties of :H Thin Films Prepared by Thermal Evaporation Method
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Thin a-:H films were grown successfully by fabrication of designated ingot followed by evaporation onto glass slides. A range of growth conditions, Ge contents, dopant concentration (Al and As), and substrate temperature, were employed. Stoichiometry of the thin films composition was confirmed using standard surface techniques. The structure of all films was amorphous. Film composition and deposition parameters were investigated for their bearing on film electrical and optical properties. More than one transport mechanism is indicated. It was observed that increasing substrate temperature, Ge contents, and dopant concentration lead to a decrease in the optical energy gap of those films. The role of the deposition conditions on values of the optical constants was determined. Accordingly, models of the density of states for the :H thin films as pure, doped with 3.5% of Al (p-type) and that doped with 3.5% As (n-type), were proposed.

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Publication Date
Tue Jan 18 2022
Journal Name
Materials Science Forum
Effect Partial Substitution of Calcium by <i>Cadmium</i> on Dielectrically Properties of Li0.4Cd0.6Ba2Ca2Cu3O10+δ System
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In this article the conventional "solid-state reaction" method was used to synthesize perovskite Li0.4Cd0.6Ba2Ca2Cu3O10+δ. Four main types of compounds were obtained by physically replacing calcium oxide with cadmium in proportions 0, 0.03, 0.06 and 0.09, the pure Li0.4Cd0.6Ba2Ca2Cu3O10+δ phase, and the phases Li0.4Cd0.6Ba2Ca1.97Cd0.03Cu3O10+δ

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Publication Date
Thu Jun 30 2011
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
CRACKING ACTIVITY OF PREPARED Y-ZEOLITE CATALYST USING CUMENE ON FLUIDIZED BED REACTOR
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The catalytic activity of faujasite type NaY catalysts prepared from local clay (kaolin) with different Si/Al ratio was studied using cumene cracking as a model for catalytic cracking process in the temperature range of 450-525° C, weight hourly space velocity (WHSV) of 5-20 h1, particle size ≤75μm and atmospheric pressure. The catalytic activity was investigated using experimental laboratory plant scale of fluidized bed reactor.
It was found that the cumene conversion increases with increasing temperature and decreasing WHSV. At 525° C and WHSV 5 h-1, the conversion was 42.36 and 35.43 mol% for catalyst with 3.54 Si/Al ratio and Catalyst with 5.75 Si/Al ratio, respectively, while at 450° C and at the same WHSV, the conversion w

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Publication Date
Sun Feb 03 2019
Journal Name
Iraqi Journal Of Physics
A study of the characterization of CdS/PMMA nanocomposite thin film
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Nanocomposites of polymer material based on CdS as filler
material and poly methyl methacrylate (PMMA) as host matrix have
been fabricated by chemical spray pyrolysis method on glass
substrate. CdS particles synthesized by co-precipitation route using
cadimium chloride and thioacetamide as starting materials and
ammonium hydroxide as precipitating agent. The structure is
examined by X-ray diffraction (XRD), the resultant film has
amorphous structure. The optical energy gap is found to be (4.5,
4.06) eV before and after CdS addition, respectively. Electrical
activation energy for CdS/PMMA has two regions with values of
0.079 and 0.433 eV.

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Publication Date
Sat Jan 01 2022
Journal Name
Technologies And Materials For Renewable Energy, Environment And Sustainability: Tmrees21gr
Optical characteristics of simulated design of parabolic trough solar concentrator
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Publication Date
Sun Jan 16 2022
Journal Name
Iraqi Journal Of Science
Simulations of Four Types of Optical Aberrations using Zernik Polynomials
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In this paper, a computer simulation is implemented to generate of an optical aberration by means of Zernike polynomials. Defocus, astigmatism, coma, and spherical Zernike aberrations were simulated in a subroutine using MATLAB function and applied as a phase error in the aperture function of an imaging system. The studying demonstrated that the Point Spread Function (PSF) and Modulation Transfer Function (MTF) have been affected by these optical aberrations. Areas under MTF for different radii of the aperture of imaging system have been computed to assess the quality and efficiency of optical imaging systems. Phase conjugation of these types aberration has been utilized in order to correct a distorted wavefront. The results showed that

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Publication Date
Fri Apr 01 2016
Journal Name
Journal Of Engineering
Absorber Diameter Effect on the Thermal Performance of Solar Steam Generator
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In this work, a convex lens concentrating solar collector is designed and manufactured locally by using 10 convex lenses (concentrator) of a diameter 10cm and one Copper absorber tube of a diameter 12.5mm and 1mm in thickness 1m length. Two axes manual Tracking system also constructed to track the sun continuously in two directions. The experiments are made on 17th of May 2015 in climatic conditions of Baghdad. The experimental data are fed to a computer program to solve the thermal performing equation, to find efficiency and actual useful energy. Then this data is used in numerical CFD software for three different absorber diameters (12.5 mm, 18.75 mm and 25 mm). From the results that obtained the maximum the

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Publication Date
Sun Feb 10 2019
Journal Name
Iraqi Journal Of Physics
The role of atmospheric non-thermal plasma in the bacteria inactivation
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Non-thermal atmospheric pressure plasma has emerged as a
new promising tool in medicine and biology. In this work, A DBD
system was built as a source of atmospheric pressure non-thermal
Plasma suitable for clinical and biological applications. E. coli and
staphylococcus spp bacteria were exposed to the DBD plasma for a
period of time as inactivation (sterilization) process. A series of
experiments were achieved under different operating conditions. The
results showed that the inactivation, of the two kinds of bacteria, was
affected (increasing or decreasing) according to operation conditions
because they affects, as expected, the produced plasma properties
according to those conditions.

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Publication Date
Wed Sep 21 2016
Journal Name
Applicable Analysis
Retrieving the time-dependent thermal conductivity of an orthotropic rectangular conductor
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Publication Date
Wed Jun 01 2022
Journal Name
Journal Of Engineering Science And Technology
THERMAL PERFORMANCE OF MULTIPLE- PASS SOLAR AIR HEATER WITH PIN FINS
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Publication Date
Fri May 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
A review of ultra-high temperature materials for thermal protection system
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Abstract<p>Ultra-High Temperature Materials (UHTMs) are at the base of entire aerospace industry; these high stable materials at temperatures exceeding 1600 °C are used to manage the heat shielding to protect vehicles and probes during the hypersonic flight through reentry trajectory against aerodynamic heating and reducing plasma surface interaction. Those materials are also recognized as Thermal Protection System Materials (TPSMs). The structural materials used during the high-temperature oxidizing environment are mainly limited to SiC, oxide ceramics, and composites. In addition to that, silicon-based ceramic has a maximum-use at 1700 °C approximately; as it is an active oxidation process o</p> ... Show More
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