An experimental and numerical study has been carried out to investigate the forced convection heat transfer by clean or dusty air in a two dimensional annulus enclosure filled with porous media (glass beads) between two vertical concentric cylinders. The outer cylinder is of (82 mm) outside diameters and the inner cylinder of (27 mm) outside diameter. Under steady state condition; the inner cylinder surface is maintained at a high temperature by applying a uniform heat flux and the outer cylinder surface at an ambient temperature. The investigation covered values of input power of (6.3, 4.884, 4.04 and 3.26 W), Reynolds number values of (300, 700, 1000, 1500, and 2000) and dust ratio values (density number N) of (2, 4, 6 and 8). A computer program in MATLAB has been built to carry out the numerical solution by writing the governing equation in finite difference method. The local Nusselt number, the average Nusselt number, the contours of temperature field and velocity field were presented to show the flow and heat transfer characteristics. The results show that when clean air flow, the wall temperature gradually increases along the cylinder length in the direction of flow and decrease as Reynolds number increase while it increases with input power. For dusty air flow results show that the wall
temperature gradually increases along the axial direction and increase with Reynolds number and with input power, and the maximum reduction in heat transfer will be 30 % for N=8 at Re=2000. Comparison was made between the present experimental and numerical results and it gives good agreement. The experimental and numerical Nusselt number follows the same behavior with a mean
deviation of 12%.
Departments and offices of public relations and media in any institution or company is the most important departments that reflect the results of their work negatively or positively on their reputation. This goes beyond the trust and credibility that its internal and external audiences will give it. Where such matter requires the staff, working in these departments and offices, to have communication skills that qualify them to do the role of marketing the communication message. Yet, the communication skills of public relations and media staff vary from person to person depending on the communication position. This skill has two criteria: Achieving the communication goal and the speed in achieving it as a number of skills
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A new type of solar air heater was designed, fabricated, and tested in Baghdad, Iraq winter conditions. The heater consists of two main parts. The horizontal section was filled with the black colored iron chip while the vertical part has five pipes filled with Iraqi paraffin wax. A fan was fixed at the exit of the air. Two cases were studied: when the air moved by natural convection and when forced convection moved it. The studied air heater has proven its effectiveness as it heated the air passing through it to high temperatures. The results manifest that using little air movement makes the temperatures, stored energies, and efficiencies of the two studied cases converge
... Show MoreThis study has been developed axes of the search, including: Search (deliberative) language and idiomatically, and Description Language (b social phenomenon), and the definition of the theory of (acts of speech), and discussed the problem of the conflict between tradition and innovation, as defined objectively have a target aimed at reviving the deliberative thought when Arab scholars , and the balance between the actual done Arab and Western rhetoric, but Meet in intellectual necessity, a sober reading that preserve the Arab language prestige, and its position in the light of the growing tongue Sciences, as long as we have inherited minds unique, and heritage huge able to consolidate the Arab theory lingual in linguistics.
The research aims at measuring the impact of visual media on the development of the tourism services sector, which is a field study for the public. It aims at determining the impact of visual media on tourism sector development, clarifying the concept of visual media and its functions and studying the role of media in the development of tourism culture among the public. For a sample of the employees of the University of Baghdad, consisting of (120) male and female. A questionnaire was prepared for this purpose consisting of (21) questions distributed to the sample. The data were analyzed and the hypotheses were tested using the statistical program spss to unload the results and calculate the frequencies, percentages and correlati
... Show MorePorous silicon (P-Si) has been produced in this work by photoelectrochemical (PEC) etching process. The irradiation has been achieved using diode laser of (2 W) power and 810 nm wavelength. The influence of various irradiation times on the properties of P-Si material such as P-Si layer thickness, surface aspect, pore diameter and the thickness of walls between pores as well as porosity and etching rate was investigated by depending on the scanning electron micrograph (SEM) technique and gravimetric measurements.
The aim of this scientific study is to diagnose the nature of the relationship between academic education in the field of media, communication and media practice. The university offers theoretical and practical lessons to students on the concepts of communication sciences, theories, models, legislations, ethics, and techniques over three years or more. And the diploma in the field of communication and Media Sciences gives students the opportunity to work in the field of journalism and media in the future, this is what many academics and media thinkers in Algeria believe, while another trend sees the exact opposite: The study of information and communication sciences within the university in the form of theoretical lessons cannot contribu
... Show MoreIn this paper, an experimental analysis of conventional air-cooled and microchannel condensers in automotive vapor compression refrigeration cycle concerning heat transfer coefficient and energy using R134a as a refrigerant was presented. The performance of two condensers and cycles tested regarding ambient temperature which it was varied from 40oC to 65oC, while the indoor temperature and load have been set to be 23oC and 2200 W respectively. Results showed that the microchannel condenser has 224 % and 77 % higher refrigerant side and air side heat transfer coefficient respectively than the coefficients of the conventional condenser. Thus, the COP, in case of using the microchannel
... Show MoreThis study is concerned with the derivation of differential equation of motion for the free coupled vertical – torsional and lateral vibration of opened thin-walled curved beams. The curved beam to be considered in this study is of isotropic opened thin – walled (I) section with equal top and bottom flanges. The derivation depends on Hamilton's principle which required finding the potential and kinetic energy of the curved beam section due to internal stresses and all types of movements (Vertical,Torsional and Lateral) .The effect of restrained warping displacement is also considered in this study. Three differential equations are derived for vertical, torsional and lateral movement .and approximate solutions are developed by using the
... Show MoreBackground: Otitis media with effusion is characterized by accumulation of fluid in the middle ear in absence of acute inflammation and it is the most common cause of acquired hearing loss in children, and may negatively affect language development failure of medical treatment of middle ear effusion frequently require myringotomy and tympanostomy tube insertion.
Objectives: To determine tympanostomy tube complications of tube in children with chronic otitis media with effusion who were treated with Shah Grommet tube insertion.
Methods: The Medical records of 162 ears of 87 children (52 male and 35 female) were reviewed respectively, the patients ages wer
... Show MoreA flight simulation programme has been developed on a personal computer using Microsoft
FORTRAN to simulate flight trajectories of a light aircraft by using Six-Degree-of-Freedom
equation of motion. The simulation has been made realistic through pre-programmed the input to
the control surfaces, atmospheric gust during the flight mode. The programme plays an important
role in the evaluation and validation of the aircraft design process. A light aircraft (Cessna 182T)
has been tested through free flight, gliding flight, flight with gust. The results show good trend and
show that the programme could be dependent as a realistic flight test programme.