Film condensation of steam on a vertical tube is investigated numerically and experimentally, in the present work. A mathematical model was set based on the basic conservation laws of mass and energy, Nusselts analysis of film condensation, and empirical equations available in the literature. Then, a simulation program in FORTRAN language was developed which simulates the film condensation of steam on a vertical tube. A complete steam tables subprogram was also developed and incorporated with the main program. The experimental work was carried out using a steam condensation test bench. The inlet and outlet cooling water temperatures, steam temperature and pressure, tube surface temperature at center, and cooling water flow rate are recorded during each experimental test run. The inlet cooling water temperature, steam temperature, and cooling water flow rate are used as an input for the numerical program, then the program calculates tube surface temperature distribution, cooling water temperature distribution, local heat transfer rate, local condensation heat transfer coefficient, condensate boundary layer thickness distribution, total heat transfer rate, and average condensation heat transfer coefficient. The effect of various parameters on the condensation heat transfer coefficient, such as steam temperature, steam-surface temperature difference, and the presence of non-condensable gas were investigated and reported graphically. It was found that increasing (steam-surface) temperature difference while keeping the steam temperature constant results in an increase in condensate boundary layer thickness, which in turn causes a decrease in condensation heat transfer coefficient. On the other hand, increasing steam temperature and keeping the (steam-surface) temperature difference constant leads to an increase in condensation heat transfer coefficient. In addition, the presence of non-condensable gas with different concentrations was also investigated and it was shown that it causes a noticeable reduction in the average condensation heat transfer coefficient. An equation for calculating average condensation heat transfer coefficient on a vertical tube was also developed. The experimental data obtained from the test runs were compared with numerical results and showed good agreement. Thus, it can be concluded that the present computational program is suitable for simulating steam condensation on a vertical tube.
Background: presence of lingual vascular foramina and canals in the interforaminal regionmay increase the risk ofsurgical complications during implant placement or any surgical procedure in this area.Aim of this study is the radiological evaluation of the anatomic characteristic of the lingual foramina and their vascular canals in the anterior of the mandible using cone beam computed tomography. Materials and Methods: Prospective study including 72 Iraqi subjects (31 male and 41 female) ranging from 20 to 59 years, all subjects attended AL- Sharaa dental clinic in AL-Najaf AL-Ashraf city, scanned with CBCT from September 2016 to February 2017. Using 3dimentional and sagittal cross section to detect lingual foramina and their vascular canals
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Public relations are amongst the social sciences that rely on scientific methods in achieving new knowledge or resolving existing problems by means of its scientific researches that are often applied and require a classification in terms of their results’ analysis. It also requires subtle statistical processes whether in constructing their material or in analyzing and interpreting their results.
This research seeks to identify the relation between public relations and statistics, and the significance a researcher or practitioner in the domain of public relations should assign to statistics being one of the important criteria in identifying the accuracy and object
... Show MoreThe probability is considered one of the grammatical cases in all languages of the world. Expressions of probability in Spanish language are expressed by various structures, expressions and some verb tenses. By this study explains the grammatical cases, the verbal periphrases, the impersonal expressions, the future tenses (simple and perfect) and the conditional mode of probability in Spanish language .We have explains these cases in detail with examples that have extracted from various spanish grammar books .The specific objective of this study is to know the resources and constructions of probability in Spanish language and their translation in Arabic language.
Accounting changes have taken place in either the local or international level has led to more disclosure from companies, and that many of the economic units in order to attract investors to negotiate on its shares price in the stock market require amendments with respect to the information disclosed, Thus, the objective of this research is to analyze whether companies were research sample disclose contingent assets and liabilities and provisions in their annual financial reports with what brought him International Accounting Standards. It has been used descriptive analysis of annual financial reports for a sample of (50) listed company on the Iraq Stock Exchange were identified companies that disclose contingent assets and liabi
... Show MoreThe new organic reagent 2-[Benzo thiazolyl azo]-4,5-diphenyl imidazole was prepared and used as complexing agent for separation and spectrophotometric determination of Cu2+ ion in some samples include plants, soil, water and human blood serum. Initially determined all factors effect on extraction method and the results show optimum pH was (pHex=9), optimum concentration was 40?g/5mLCu2+ and optimum shaking time was (15min.), as well stoichiometry study appears the complex structure was 1:1 Cu2+: BTADPI. Interferences effect of cations were studied. Synergism effect shows MIBK gave increasing in distribution ratio (D). Organic solvent effect appears there is no any linear relation between dielectric constant for organic solvent used and dis
... Show MoreThe concept of TQM is based on one of the concepts that combine administrative and innovative methods. The aim of the research is to demonstrate the dimensions of TQM in enhancing the satisfaction of the taxpayers through a survey of a sample of officials in the General Authority for Taxation and 50 officials. In the collection of data and information, and the results were analyzed using the SPSS program to find the most important compounds and factors in he method of analysis.
The research problem was represented by the non-application of the General Authority for Taxation to the entrances and modern practices in the administrative work. The results of some of the complications that accompany the tax accounting process, which af
... Show MoreA new ligand [ 2-chloro-N- (1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro -1H-pyrazol- 4-ylcarbamothioyl)acetamide](L) was synthesized by reacting the Chloro acetyl isothiocyanate with 4-aminoantipyrine,The ligand was characterized by(C HNS) elemental microanalysis and the spectral measurements including Uv-Vis ,IR ,1H and13C NMR spectra, some transition metals complex of this ligand were prepared and characterized by Uv-Vis, FT-IR spectra, conductivity measurements, magnetic susceptibility and atomic absorption. From the obtained results the molecular formula of all prepared complexes were [M(L)2(H2O)2]Cl2 (M+2 =Mn, Co, Ni, Cu, Zn, Cd and Hg),the proposed geometrical structure for all complexes were octahedral.
To achieve excellence in the quality of performance in school sports administration, which has suffered a lot of problems and constraints on the administrative system, supervision and education level as well as the regulatory environment and available resources available and contribute to the provision of some processors and overcome difficulties to participate in the formation of the individual good of itself and society through sports activities. Hence the importance came this study to create a reference to the quality of the performance criteria school sports from the perspective of supervisors (specialists and technicians) in the districts of breeding Baghdad, to be of help to all those involved in school sports and maintaining an excep
... Show MoreThe fluorescence emission of Rhodamine 6G (R6G) and Acriflavine dyes in PMMA polymer have been studied by changing the irradiation and exposure time of laser light to know the effect of this parameter. It was found that the fluorescence intensity decreases in the polymer samples doped dyes as the exposure time increases and then reaches stabilization at long times, this behavior called photobleaching, which have been shown in liquid phase less than solid phase. Using 2nd harmonic with wavelength 530 nm laser, the photobleaching effect in the two dye-doped polymers different solvent but same was studied. It was observed that photobleaching of by different solution and by using dip spin coating the photobleaching seem in liquid phase more
... Show MoreThe objective of present study was to compare of several methods for estimating the degree of heritability and calculating the number of genes using generation mean analysis of maize (