The aim of this work is to develop an axi-symmetric two dimensional model based on a coupled simplified computational fluid dynamics (CFD) and Lagrangian method to predict the air flow patterns and drying of particles. Then using this predictive tool to design more efficient spray dryers. The approach to this is to model what particles experience in the drying chamber with respect to air temperature and humidity. These histories can be obtained by combining the particles trajectories with the air temperature/humidity pattern in the spray dryer. Results are presented and discussed in terms of the air velocity, temperature, and humidity profiles within the chambers and compared for drying of a 42.5% solids solution in a spray chamber 2.22m in diameter with a cylindrical top section 2.00m high and a bottom cone section 1.725m high.
In this work, the optical properties of Cu2S with different thickness
(1400, 2400, 4400) Ǻ have been prepared by chemical spray pyrolys
is method onto clean glass substrate heated at 283 oC ±2. The effect
of thickness on the optical properties of Cu2S has been studied. It
was found that the optical properties of the electronic transitions on
fundamental absorption edge were direct allowed and the value of the
optical energy gap of Cu2S (Eg) for direct transition decreased from
(2.4-2.1) eV with increasing of the thickness from (1400 - 4400)Ǻ
respectively. Also it was found that the absorption coefficient is
increased with increasing of thicknesses. The optical constants such<
Spray pyrolysis technique was subjected to synthesized (SnO2)1-x (TiO2: CuO) x Thin films on different substrates like glass and single crystal silicon using. The structure of the deposited films was studied using x-ray diffraction. A more pronounced diffraction peaks of SnO2 while no peaks of (CuO , TiO2 ) phase appear in the X-ray profiles by increasing of the content of (TiO2 , CuO) in the sprayed films. Mixing concentration (TiO2 , CuO) influences on the size of the crystallites of the SnO2 films ,the size of crystallites of the spray paralyzed oxide films change in regular manner by increasing of (TiO
... Show MoreABSTRACT: Thin film of CdS has been deposited onto clean glass substrate by using Spray pyrolysis technique. Results of Morphological (AFM) studied; electrical properties and optical conductivity studied are analysis. AFM results show a crystalline nature of the films. From the conductivity measurement at different temperatures, the activation energy of the films was calculated and found to be between 0.188 - 0.124 eV for low temperature regions, and between 1.67-1.19eV for high temperature regions. Hall measurements of electrical properties at room temperature show that the resistivity and mobility of CdS polycrystalline films deposited at 400 C0, were 3.878x103 . cm and 1.302x104cm2/ (V.s), respectively. The electrical conductivity of th
... Show MoreShe noted most of the results of research conducted on the use of computers and the Internet in the areas of administrative, economic, agricultural and educational to a significant improvement in learning outcomes of these groups in the development of mechanisms of action, has increased rates of computer use and applications in various spheres of life at very fast pace so that the computer and the Internet is a vital part of any activity, whether administrative or research or the media, hence it can be said that the use of computers and the Internet in the management of public relations activities in any organization can accelerate the pace of echo positive goals and purposes of public relations, this study comes to looking at us
... Show MoreIn this paper the effect of nonthermal atmospheric argon plasma on the optical properties of the cadmium oxide CdO thin films prepared by chemical spray pyrolysis was studied. The prepared films were exposed to different time intervals (0, 5, 10, 15, 20) min. For every sample, the transmittance, Absorbance, absorption coefficient, energy gap, extinction coefficient and dielectric constant were studied. It is found that the transmittance and the energy gap increased with exposure time, and absorption. Absorption coefficient, extinction coefficient, dielectric constant decreased with time of exposure to the argon plasma
Effect of copper doping and thermal annealing on the structural and optical properties of Zn0.5Cd0.5S thin films prepared by chemical spray pyrolysis have been studied. Depositions were done at 250°C on glass substrate. The structural properties and surface morphology of deposited films were studied using X-ray diffraction (XRD) and photomicroscope (PHM) techniques. XRD studies reveal that all films are crystalline tetragonal structure. The film crystallinity are increased with 1% Cu-doping concentration and also increased for the films annealed at 300°C than the other studied cases. The lattice constant 'a' and 'c' varies with doping concentrations from 5.487Å to 5.427Å and 10.871Å to 10.757Å respectively. The grain size attained
... Show MoreTin dioxide (SnO2) were mixed with (TiO2 and CuO) with concentration ratio (50, 60, 70, 80 and 90) wt% films deposited on single crystal Si and glass substrates at (523 K) by spray pyrolysis technique from aqueous solutions containing tin (II) dichloride Dihydrate (SnCl2, 2H2O), dehydrate copper chloride (CuCl2.2H2O) and Titanium(III) chloride (TiCl3) with molarities (0.2 M). The results of electrical properties and analysis of gas sensing properties of films are presented in this report. Hall measurement showed that films were n-type converted to p- type as titanium and copper oxide added at (50) % ratio. The D.C conductivity measurements referred that there are two mechanisms responsible about the conductivity, hence it possess two act
... Show MoreThis study produces an image of theoretical and experimental case of high loading stumbling condition for hip prosthesis. Model had been studied namely Charnley. This model was modeled with finite element method by using ANSYS software, the effect of changing the design parameters (head diameter, neck length, neck ratio, stem length) on Charnley design, for stumbling case as impact load where the load reach to (8.7* body weight) for impact duration of 0.005sec.An experimental rig had been constructed to test the hip model, this rig consist of a wood box with a smooth sliding shaft where a load of 1 pound is dropped from three heights.
The strain produced by this impact is measured by using rosette strain gauge connected to Wheatstone
Background: Historically the traditional medical program are divided into preclinical basic sciences course which taught separately (subject based) and clinical course which taught also as subject based, spoon feeding ,few delivery modes , no or few interactive session and the assessment solely based on examination and no weightage is given to the continuous assessment.Curricular reform: In the last few decades, there have been increasing pressures on medical educators for curriculum reform, and many accreditation bodies were established a guidelines for the medical schools. In many countries, the traditional approach has largely been modified towards a more integrated approach. An integrated approach is still subject centered but transc
... Show MoreThe goal of the research is to find the optimization in the test of the appropriate cross-over design for the experiment that the researcher is carrying out (under assumption that there are carry-over effects of the treatments) to posterior periods after the application period (which is often assumed to be the first period). The comparison between the double cross-over design and the cross-over design with extra period. The similarities and differences between the two designs were studied by measuring the Relative Efficiency (RE) of the experiment.