The enhancement of heat exchanger performance was investigated using dimpled tubes tested at different Reynolds numbers, in the present work four types of dimpled tubes with a specified configuration manufactured, tested and then compared performance with the smooth tube and other passive techniques performance. Two dimpled arrangements along the tube were investigated, these are inline and staggered at constant pitch ratio X/d=4, the test results showed that Nusselts number (heat transfer) of the staggered array is higher than the inline array by 13%. The effect of different depths of the dimple (14.5 mm and 18.5 mm) has been also investigated; a tube with large dimple diameter enhanced the Nusselts number by about 25% for the range of Reynolds number between 4000- 20000. The overall enhancement ratio was used to differentiate the passive technique and comparison of different configurations for the technique itself, the result depicted that the 10 mm dimple diameter with a pitch ratio of X/d= 4 gives better performance than the static mixer and twisted tape techniques. The overall enhancement ratio of the 10 mm dimple diameter is varied from (1.21 to 1.65) that means good performance for a range of Reynolds numbers (4000-20000). This indicates that 21- 65 % of heat transfer area can be saved at the same pumping power compared with the smooth tube heat exchanger.
The current research aims to highlight the role of human resource management with its practices (human resource planning, selection and placement, training and development, performance evaluation, compensation, and incentives) in raising the level of individuals' performance and its dimensions (task performance, contextual performance, unproductive work behavior, and adaptive performance) by explaining the research problem, which can be limited to the low level of performance of individuals, where the researchers use the descriptive analytical approach and the SPSS program in the practical aspect of the research community represented by the general manager and his assistant
The interest in pre-service teacher training has become influential in teaching English as a foreign language, and the purpose of this training course is to prepare qualified teachers to teach effectively through the application of this technique by undergraduate students. This research aims to find out the effect of using the seven principles of good practice as a teaching technique on the fourth stage student-teachers’ performance at the College of Education for Women/University of Baghdad, during the academic year 2017-2018. The sample includes (60) students selected according to the stratified sampling method. The observational checklist used by the department to assess the student teachers’ performance during the practicum perio
... Show MoreThis study has been carried out in the Station of Poultry Researches which is affiliated to the General Office of Agricultural Researches / Ministry of Agriculture during the period from 01/04/2018 to 14/05/2018 there are 300 one day old chick of type (Ross 308) used in this study, and has been fed on diets which green tea powder (Camellia sinensis) has been added to it with the levels 0.5 , 1 , 1.5 , 2 g/kg as a feed for the treatments T 2 , T 3 , T 4 and T 5 respectively and compared to the control treatment T 1 which is devoid of addition, every treatment included three replicates each one has 20 birds in order to study the effect of adding a various levels of green tea powder (Camellia sinensis) to the diet on the productive performance
... Show MoreThe study aims to know the nature of the expected relationship between market share management strategies and the variation in the performance of the shares of a number of Iraqi industrial companies listed in the Iraqi Stock Exchange. For the period (2005-2018) in the light of both the monthly closing prices and sales volume during the research period, the (Panel Data) method was relied on through a stylistic test (fixed effects model and random effects model), and the results determined the need to adopt the fixed effects model method for sample data and test Assumptions, the results showed the positive impact of market share according to its strategies on the performance of stocks according to its studied indicators (Treynor index
... Show MoreThe research aims to determine the role of knowledge management to measure performance on a sample of faculties of Administration and Economics the University of Kufa, and to achieve this goal through a researcher from the theoretical literature and research and studies related to the construction of the scheme shows the hypothetical relationship between the variables, which was adopted by the independent variable knowledge management, distributed four variables are: (knowledge generation, knowledge storage, knowledge dissemination, the application of knowledge), as well as four variables representing the variables adopted for the performance of the university are:
(to reduce costs and increase profits, improve quality, scie
Abstract
The study aims to clarify the impact of the adoption of the International Financial Reporting Standard (IFRS16) on lease contracts in the General Iraqi Insurance Company on the financial statements, and thus the impact on financial ratios and indicators, Since the financial reporting standard considers lease contracts as an asset called the right to use the asset and is offset by a liability, this changes the way the financial statements are presented, with an addition to both the asset and liability sides. In order to show the extent to which the adoption of the standard reflects on the financial performance
... Show MoreThis study has been done for testing the effectiveness and efficiency of probiotic in its ability to inhibit Aspergillus flavus , which secretes the aflatoxin B1 and compare it with materials that were approved to be effective in the inhibition of the growth of fungi and break down and reduction of mycotoxin. these are the filax substance and ozone gas. A laboratory experiment has been conducted to determine the isolates out of the fungus producing the aflatoxin B1.the isolate producing aflatoxin B1 has grown on the yellow corn seed. the probiotic was added along with the filax and they have been exposed to ozone gas and then they were stored from 30 days. A bio test was con conducted to knw the effects of biological toxin on the broiler me
... Show MoreVarious assays are used to determine the toxic effects of drugs at cellular levels in vitro. One of these methods is the dye exclusion assay, which measures membrane integrity in the presence of Trypan blue. Trypan blue the dye which was used in this study to investigate cytotoxic effect of a new Cis –dichloroplatinum (II) complex [(Qu)2PtCl2] on the viability of polymorphonuclear cells (PMNs). Three concentrations of platinum complex were prepared (70, 35and 17.5 µg/ ml) and the results revealed that the percentage of cell viability decreased as the platinum complex concentration increased in comparison with control.
... Show MoreThis study aims to create spatial balance between two Iraqi writers' novels (Maysaloon
Hadi, Alya Talib) technical and objective illustrates similarity points and difference in the
writers' style. We depended in our research on spatial classification considering the aggressive
and friendly, since the writers focused on them.
The research study concluded to many sides, some of which are similar and some are
different. Firstly, ingenuity description of the writers. Followed by the deep connection they
have. Because of the personal experience it emanated from alienation sensations and nostalgia
to deep roots to homeland.
On the other hand, difference aspects, we see Maysaloon takes symbols and illusions
unlike Aly