The numerical investigation has been performed to study the radiation affected steady state laminar mixed convection induced by a hot inner varied positions circular core in a horizontal rectangular channel for a fully developed flow. To examine the effects of thermal radiation on thermo fluid dynamics behavior in the eccentric geometry channel, the generalized body fitted co-ordinate system is introduced while the finite difference method is used for solving the radiative transport equation. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function. After validating numerical results for the case without radiation, the detailed radiation effect is discussed. From the parametric study, the Nusselt number (Nu) distributions in steady state were obtained for Aspect Ratio AR (0.55-1) and Geometry Ratio GR (0.1-0.9). The fluid Prandtl number is 0.7, Rayleigh number (0 ≤ Ra ≤ 104), Reynolds number Re (1-2000), Optical Thickness (0 ≤ t ≤ 10), Conduction-Radiation parameter (0 ≤ N ≤ 100) for the range of parameters considered. It is indicated in the results that heat transfer from the surface of the circular core exceeds that of the rectangle duct and when circular core is lower than the center of the channel, the rate of heat transfer decreased. The correlation equations are concluded to describe the radiation effect.
Phosphorus is usually the limiting nutrient for eutrophication in inland receiving waters; therefore, phosphorus concentrations must be controlled. In the present study, a series of jar test was conducted to evaluate the optimum pH, dosage and performance parameters for coagulants alum and calcium chloride. Phosphorus removal by alum was found to be highly pH dependent with an optimum pH of 5.7-6. At this pH an alum dosage of 80 mg/l removed 83 % of the total phosphorus. Better removal was achieved when the solution was buffered at pH = 6. Phosphorus removal was not affected by varying the slow mixing period; this is due to the fact that the reaction is relatively fast.
The dosage of calcium chloride and pH of solution play an importa
The measurements of major and trace elements in different brands of milk powder selected from the Iraqis market via the X-ray fluorescence (XRF) Technique have been studied in the present work. The result of the measurements reveals the high concentrations of sodium, phosphorus, sulfur, chlorine, potassium, calcium and magnesium. Furthermore, low concentrations of aluminum, silicon, iron, bromine, molybdenum, iodine, barium, titanium, manganese, cobalt, chrome, nickel, copper, zinc and lead were detected. Neutron activation analysis (NAA) and Kjeldahl technique were also employed to determine the concentrations of nitrogen. It was found that the nitrogen concentration was in the range of (1.96 - 3.23) % which is within the permissible li
... Show MoreAbstract
The study discussed three areas in strategic thinking, namely, (patterns elements, outcomes) , this study aimed to measure extent to which strategic leaders have the type or types of patterns of strategic thinking, and measure the extent of their use of the elements of strategic thinking, and measurement of strategic thinking outcomes for managers at various levels , And to know the relationship between the modes of strategic thinking, elements and outcomes in organizations. the study included five banks and four hospitals and four colleges and universities, has been a research sample consisted of 168 individuals, distributed in positions (Director General , Director of Directorate , Director of
... Show MoreThe research aims to find the impact of a proposed strategy according to the Luria model on realistic thinking among fifth-class scientific students and their achievement in mathematics. To achieve it, the experimental research method and the quasi-experimental design were used for two equal groups, one of them is a control group taught in traditional way and the other is an experimental one taught according to strategy based on Luria model. The research community represents the students of the fifth scientific class from the General Directorate of Education of Karkh First. The research sample (40) students were deliberately chosen and distributed equally between the two groups after making sure that they were equals in their previo
... Show MoreThe present project involves photodegrading the dye solochrom violet under advanced oxidation techniques at (25 oC) temperature and UV light. Zinc Oxide (ZnO) and UV radiation at a wavelength of 580 nm were used to conduct the photocatalytic reaction of the solochrom violet dye. One of the factors looked into was the impact of the starting conditions. pH, the amount of original hydrogen peroxide, and the dye concentration time radiation were used. For hours, the kinetics and percentages of degradation were examined at various intervals. In general, it has been discovered that the photodegradation rates of the dye were greater when H2O2 and ZnO were combined with UV light. The best wavelength to use was determined. Modern oxidation techni
... Show MoreThis article includes the preparation of luminescence materials from rare earth (Eu ) ion doping Yttrium Oxide (Y2O3) 70% and SiO2 25% and study the characteristics of phosphors for ultraviolet to visible conversion. The phosphor materials have been synthesized by two steps: Preparing the powder by solid state method using Y2O3, SiO2 and Eu2O3 with doping materials concentration (70%, 25% and 5%) respectively and different calcination temperature (1000, 1200 and 1400 oC).
The second step is to prepare the colloid solution by dispersing the produced powder in a polyvinyl alcohol solution (4%) .
Powde
... Show MoreIn this study, a system of nonthermal plasma that was operated under atmospheric pressure and was powered by argon gas was employed. The particular plasma properties are affected by changes in the Ar gas flow ranges from 0.5 to 2.5 l/min, product by stream of the plasma jet that is utilized. By using the aforementioned method generated from AC and DC. After placing Ar gas as the cathode, which represents the negative pole, flows toward the anode, which is represented by a tiny metal plate of Zn measuring 6 × 1 cm2 in size, with a submerged part of 4 cm2 long, with both types of current employed having a high voltage of 13.5 kV and the frequency of AC was 30 kHz, we measured these variable parameters. It has been shown that when argon f
... Show MoreIn this study, experimental and numerical applied of heat distribution due to pulsed Nd: YAG laser surface melting. Experimental side was consists of laser parameters are, pulse duration1.3
The aim of this paper is to present a weak form of -light functions by using -open set which is -light function, and to offer new concepts of disconnected spaces and totally disconnected spaces. The relation between them have been studied. Also, a new form of -totally disconnected and inversely -totally disconnected function have been defined, some examples and facts was submitted.