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 research aims to identify the administrative skills and their role in institutional performance, and used the descriptive approach in a survey style and correlational relations to suit the nature of the problem to be studied.The research community was identified with the directors of sports activity in the Iraqi universities in a deliberate manner, and their number is (134) directors, where two scales (administrative skills and institutional performance) were used and the two scales were distributed to the above-mentioned sample in order to obtain answers that meet the required and representative sample of the community on the day 3/12/2021. The answers to all the statements were completed and after processing the results statistically
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The research stems from the problem that focuses on a number of questions. They are as follows: What is the extent of interest in the topic of efficiency by the banks and their role in raising the efficiency of the banking business and its development? Is the banking efficiency used in Iraqi banks clear and specific for the Iraqi banking sector? How the banking sector efficiency is measured and what are the approaches adopted in determining the banking inputs and outputs? What is the level of efficiency in the research sample of the banks and what are the causes of its decline or rise in private banks individually and in the Iraqi banking sector in general?
The re
... Show MoreThe current study aims to test the impact of green training and development on sustainable performance and explore its effects within and outside the Iraqi Ministry of Environment. The main research problem revolves around the question of the extent of implementing green training and development and sustainable performance in the ministry (What is the nature of the relationship between green training and development and sustainable performance in the ministry?). To clarify the relationship between the research variables, two main hypotheses were formulated along with sub-hypotheses. The study also aims to assess the level of the ministry's interest in the research variables and provide key recommendations to enhance sustainable performan
... Show MoreThis research a mining at evaluation the efficiency of the nursing performance depended on standards of W.H.O. via application standards of W.H.O on the nursing personnel in medical city office, in light of it, it has design world evaluation list, and a sample was chosen from the nursing personnel in given researched the organization whom they are evaluated according to the standards of W.H.O for the nursing performance included of ten standards, divided in to 45 question , besides the evaluation list, the researcher get assistance of some tools of collection information via actual checking and personal interviews, a number of statistical means were used to manipulate t
... Show MoreIn this research we have tackled the role of Talent management (as a private variable) within (the Talent attraction, the Talent management performance, Talent development and Talent retention) on strategic performance reinforcement ( accredited variable) within its dimensions ( financial perspective, costumer perspective, internal operations perspective and learning and development perspective). The research conducted on sample of some college teachers from two of Sumer's colleges. The research problem represented by the broad organization's competition as well as universities; which led these colleges to investigate it's skillful human staff to meet it's strategic performance.
To meet the aims of
... Show MoreIn recent years, the Global Navigation Satellite Services (GNSS) technology has been frequently employed for monitoring the Earth crust deformation and movement. Such applications necessitate high positional accuracy that can be achieved through processing GPS/GNSS data with scientific software such as BERENSE, GAMIT, and GIPSY-OSIS. Nevertheless, these scientific softwares are sophisticated and have not been published as free open source software. Therefore, this study has been conducted to evaluate an alternative solution, GNSS online processing services, which may obtain this privilege freely. In this study, eight years of GNSS raw data for TEHN station, which located in Iran, have been downloaded from UNAVCO website
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This study aims to find the relationships between social capital (social network, social trust, shared goals) and knowledge sharing (knowledge Donating, knowledge collecting) as independent variables and their impact on improving the quality of educational services (academic staffs quality, Quality of teaching methods and study curriculums). This research is an important, because it attempts to identify the relationship between social capital and the knowledge sharing and their effect on improving the quality of educational service for universities. The study problem was determined in several questions related to the nature of the correlation relationship - the impact between the different independent variables (
... Show MoreThe effect of operating parameters on the batch scale separation of hydrocarbon mixture (benzene and hexane) using
emulsion liquid membrane technique is reported. Sparkleen detergent was used as surfactant and heavy mineral oil as
solvent to receive the permeates.
From the experimental results, the parameters that influenced the permeation are, composition of feed, contact time
with solvent, ratio of volume of solvent to volume of hydrocarbon feed, ratio of volume of surfactant solution to volume
of hydrocarbon feed, surfactant concentration, mixing intensity and glycerol as polar additive in the surfactant solution
to eliminate drop breakup.
The best conditions for the separation in this study were found to be: comp
The aim of this study is to investigate the ability of malachite green (MG) combined with 650nm diode laser to kill Candida albicans and to spectrally study the MG photodegradation after photodynamic therapy (PDT) spectrally. Cultures of Candida albicans were exposed to 40mW, 650 nm diode laser in the absence of MG. In PDT group, the MG was added to the Candida suspension for 5 min then exposed to diode laser for (5, 10, 15, 20) min at power density of 0.59W/cm2. The absorption spectrum of the photosensitized fungal suspension was obtained. The data were submitted to T-test (p<0.05). A 650nm diode laser in the presence of MG reduced the number of CFU/ml in 98.4%. Laser with 650nm alone and MG alone did not reduce significantly the num
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