Different thicknesseses of polycrystalline ZnTe films have been deposited on to glass substrates by vacuum evaporation technique under vacuum 2.1x10-5 mbar. The structural characteristics studied by X-ray diffraction (XRD) showed that the films are polycrystalline and have a cubic (zinc blende ) structure. The calculated microstructure parameters revealed that the crystallite size increases with increasing film thicknesses. The optical measurements on the deposited films were performed in different thicknesseses [ 400 , 450 and 500]nm, to determine the transmission spectrum and the absorption spectra as a function of incident wavelength. The optical absorption coefficient (α) of the films was determined from transmittance spectra in the range of wavelength (400-1100) nm. The dependence of absorption coefficient, on the photon energy showed the occurrence of a direct transition with band gap energy from 2.24eV to 1.92eV (for ZnTe films of different thicknesseses), where with high film thicknesses there are several energy levels resulting in several overlapping energy bands in the band gap of these films. The overlapping energy bands therefore tend to reduce the energy band gap, resulting in lower band gaps for thicker films.
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In this investigation, the mechanical properties and microstructure of Metal Matrix Composites (MMCs) of Al.6061 alloy reinforced by ceramic materials SiC and Al2O3 with different additive percentages 2.5, 5, 7.5, and 10 wt.% for the particle size of 53 µm are studied. Metal matrix composites were prepared by stir casting using vortex technique and then treated thermally by solution heat treatment at 530 0C for 1 hr. and followed by aging at 175 0C with different periods. Mechanical tests were done for the samples before and after heat treatment, such as impact test, hardness test, and tensile test. Also, the microstructure of the metal matrix composites was examine
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This research discusses the logic of the balance of power in the field of International Relations. It focuses on the structural-systemic version of the theory because of its centrality to the realist research program within the field. The paper examines the conventional wisdom, which argues that balances of power, in a self-help system, will form regardless of the state’s motives (or intentions); It emerges as an unintended recurring consequence of the interaction of units in anarchy, which primarily seeks superior, not an equal power. This logic assumes that hegemony does not form (or fail) in a multi-state system, because its threats (actual or perceived) to the system instill fear and provoke counterbalancing behavior by other state
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ABSTRACTObjective: The objective of this study is to develop a controlled release matrix tablet of candesartan cilexetil to reduce the frequency of administration,enhance bioavailability and improve patient compliance; a once daily sustained release formulation of candesartan cilexetil is desirable.Methods: The prepared tablets from F1 to F24 were evaluated with different evaluation parameters like weight variation, drug content, friability,hardness, thickness and swelling ability. In vitro release for all formulas were studied depends on the type and amount of each polymer, i.e. (16 mg,32 mg and 48 mg) respectively beside to the combination effect of polymers on the release of the drug from the tablet.Results: In vitro release show
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Kidney damage in workers within environments of highly expected exposure to toxin, including heavy metals, could be a primary marker to expect hazards in population exposed to low levels of many environmental pollutants. The present study was designed to evaluate the possible effect of environmental exposure to cadmium and zinc on renal function among painters in Sulaimani city. Cross sectional study was performed on 37 male painting workers in Sulaimani city. Each worker was interviewed using structured questionnaire. Twenty five non-exposed healthy subjects were included as control group. Venous blood samples (10 ml) were obtained by vein puncture from both subjects and utilized for estimation of serum urea, creatinine levels, serum le
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Steel fiber aluminum matrix composites were prepared by atomization technique. Different air atomization conditions were considered; which were atomization pressure and distance between sample and nozzle. Tensile stress properties were studied. XRF and XRD techniques were used to study the primary compositions and the structure of the raw materials and the atomized products. The tensile results showed that the best reported tensile strength observed for an atomization pressure equal to 4 mbar and sample to nozzle distance equal to 12 cm. Young modulus results showed that the best result occurred with an air atomization pressure equal to 8 mbar and sample to nozzle distance equal to 16cm
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Polypyrrole/silver (PPy/Ag) nanocomposites was synthesized via a chemical oxidative method. The AFM analysis is performed to study the surface roughness, morphology and size distribution of the PPy particles and PPy-ag nanocomposites. The results indicated that as the concentration of Ag in the nanocomposite increases, the roughness also increases. The size of nanoparticles was also evaluated and found in the range of 15 nm to 125 nm. The PPy/Ag nanocomposites exhibited an effectiveness against Gram-negative Escherichia coli showing an inhibition zone of 4mm and displayed poor efficacy against Gram-positive Staphylococcus aureus. Based on given adequate antibacterial characteristics of PPy/Ag nanocomposites, it can be identified as
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