Thermal pyrolysis kinetics of virgin high-density polyethylene (HDPE) was investigated. Thermal pyrolysis of HDPE was performed using a thermogravimetric analyzer in nitrogen atmosphere under non-isothermal conditions at different heating rates 4, 7, 10 °C/min. First-order decomposition reaction was assumed, and for the kinetic analysis Kissinger-Akahira-Sunose(KAS), Flynn-Wall-Ozawa(FWO) and Coats and Redfern(CR) method were used. The obtained values of average activation energy by the KAS and FWO methods were equal to137.43 and 141.52 kJ/mol respectively, these values were considered in good agreement, where the average activation energy value obtained by CR equation methods was slightly different which equal to 153.16 kJ/mol.
The effect of approaching nozzle jet from the deposition surface
on structural, optical and morphology properties of copper oxide thin
films was studied. The film was prepared by homemade fully
computerized CNC spray pyrolysis deposition technique at
preparations speed (3, 4, 5, and 6 mm/sec). The repeated line mode
was used at deposition temperature equal 450 °C whereas the
spraying time was in the range of (15-30 min) according to the
deposition speed. The film exhibit polycrystalline structure with
preferred orientation along (-111), (022) and (011), (002) at a 2θ
value of (35.63o) and (38.8o) respectively. Optical band gaps were
recorded at these speed shows variance in value from (1.53-2.08 eV).
Fi
Numerical simulation of charge density produced in plasma actuators is dependent upon the development of models dealing with electrical properties. The main aim of this work is to investigate the characteristics surface charge density and space charge density of DBD plasma actuator. A simple design of surface dielectric barrier discharge plasma actuator is used in the study. The discharge gas was N2:H2 mixture with applied voltage equal to 1.5 kV. A theoretical plasma model is used to establish the charge density details. Results show that surface charge density increased in value and spread in width alone the exposed electrode as the voltage increased and reached to the amplitude value.
An analytical expression for the charge density distributions is derived based on the use of occupation numbers of the states and the single particle wave functions of the harmonic oscillator potential with size parameters chosen to reproduce the observed root mean square charge radii for all considered nuclei. The derived expression, which is applicable throughout the whole region of shell nuclei, has been employed in the calculations concerning the charge density distributions for odd- of shell nuclei, such as and nuclei. It is found that introducing an additional parameters, namely and which reflect the difference of the occupation numbers of the states from the prediction of the simple shell model leads to obtain a remarkabl
... Show MoreBackground: Chronic hepatitis B virus (HBV) infection is a common health problem that has a worldwide distribution. Apart from the direct effect of the virus on the liver, there are many extrahepatic manifestations among which the probable effect on bone turnover associated with low bone mineral density (BMD). Objectives: This study aimed to determine the association between treated and untreated chronic HBV infection with BMD. Methods: This is a cross-sectional study which included a total of 48 patients with chronic HBV (28 patients treated with tenofovir-disoproxil-fumarate [TDF] antiviral drug and 20 patients have not yet started treatment). Other age- and sex-matched 30 apparently healthy individuals were recruited to represent the hea
... Show MoreBackground: Oral lichen planus (OLP) is a chronic inflammatory disease with an autoimmune inflammatory pathogenesis. The purpose of this study was to evaluate the role of angiogenesis in the pathogenesis of OLP, using CD34 stain to highlight the blood vessels for measuring the microvessel density (MVD) as well as to evaluate the relation of this marker with the degree of inflammation Materials and Methods: Immunohistochemical (IHC) staining technique was used to evaluate angiogenesis using CD34 in 46 paraffin blocks 10 of them obtained from normal mucosa and 36 from cases diagnosed as lichen planus , 20 of them diagnosed as Reticular type while 16 as erosive type. Severity of inflammation was divided into mild, moderate and severe accordi
... Show MoreAim of the research is the study of improving the performance of the thermal station south Baghdad and the main reasons for reduced its efficiency. South Baghdad power planet comprises (6) steam turbine units and (18) gas turbine units .The gas turbine units are composed of two groups: the first group is made up of gas units (1,2), each of capacity (123) MW. The design efficiency of gas turbine units is 32%. The actual efficiency data of steam units is 18.3% instead of 45% which is the design efficiency. The main reason for efficiency reduction of gas units is the rejected thermal energy with the exhaust gases to atmosphere, that are (450-510) ℃.The bad type of fuel used (heavy) fuel. Another reason for the low efficiency and has a neg
... Show MoreDensity Functional Theory (DFT) calculations were carried out to study the thermal cracking for acenaphthylene molecule to estimate the bond energies for breaking C8b-C5a , C5a-C5 , C5-C4 , and C5-H5 bonds as well as the activation energies. It was found that for C8b-C5a , C5-C4 , and C5-H5 reactions it is often possible to identify one pathway for bond breakage through the singlet or triplet states. The atomic charges , dipole moment and nuclear – nuclear repulsion energy supported the breakage bond .Also, it was found that the activation energy value for C5-H5 bond breakage is lower than that required for C8b-C5a , C5a-C5 , C5-C4 bonds which refer to C5-H5 bond in acenaphthylene molecule are weaker than C8b-C5a , C5a-C5 , C5-C
... Show MoreExperimental results for the density of states of hydrogenated amorphous silicon due to Jackson et al near the valence and conduction band edges were analyzed using Levenberg-Marquardt nonlinear fitting method. It is found that the density of states of the valence band and the conduction band can be fitted to a simple power law, with a power index 0.60 near the valence band edge, and 0.55 near the conduction band edge. These results indicate a modest but noticeable deviation from the square root law (power index=0.5) which is found in crystalline semiconductors. Analysis of Jackson et al density of states integral J(E) data over about (1.4 eV) of photon energy range, showed a significant fit to a simple power law with a power index of 2.11
... Show MoreThermal conductivity of compacted bentonite is one of the most important properties where this type of clay is proposed for use as a buffer material. In this study, Lee's disc method was used to measure the thermal conductivity of compacted bentonite specimens. The experimental results have been analyzed to observe the three major factors affecting the thermal conductivity of bentonite buffer material. While the clay density reaches to a target value, the measurement is taken to evaluate the thermal conductivity. By repeating this procedure, a relationship between clay dry density and thermal conductivity has been established in specimens after adjusting the water contents of the bentonite by placing its specimens in a drying oven for diffe
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