Due to the potential cost saving and minimal temperature stratification, the energy storage based on phase-change materials (PCMs) can be a reliable approach for decoupling energy demand from immediate supply availability. However, due to their high heat resistance, these materials necessitate the introduction of enhancing additives, such as expanded surfaces and fins, to enable their deployment in more widespread thermal and energy storage applications. This study reports on how circular fins with staggered distribution and variable orientations can be employed for addressing the low thermal response rates in a PCM (Paraffin RT-35) triple-tube heat exchanger consisting of two heat-transfer fluids flow in opposites directions through the inner and the outer tubes. Various configurations, dimensions, and orientations of the circular fins at different flow conditions of the heat-transfer fluid were numerically examined and optimized using an experimentally validated computational fluid-dynamic model. The results show that the melting rate, compared with the base case of finless, can be improved by 88% and the heat charging rate by 34%, when the fin orientation is downward–upward along the left side and the right side of the PCM shell. The results also show that there is a benefit if longer fins with smaller thicknesses are adopted in the vertical direction of the storage unit. This benefit helps natural convection to play a greater role, resulting in higher melting rates. Changing the fins’ dimensions from (thickness × length) 2 × 7.071 mm2 to 0.55 × 25.76 mm2 decreases the melting time by 22% and increases the heat charging rate by 9.6%. This study has also confirmed the importance of selecting the suitable values of Reynolds numbers and the inlet temperatures of the heat-transfer fluid for optimizing the melting enhancement potential of circular fins with downward–upward fin orientations.
The aim of this research is to identify the role of strategic agility achieving organizational excellence in one of the formations of the Ministry of Municipalities (Dhi Qar Sewage Directorate), as important service organizations that have a key role in serving and developing the society which faced many administrative challenges and issues and as a result of the changes in the environment is continuing and accelerating, so the adoption of modern administrative concepts such as strategic Agility and knowledge of their role in achieving organizational excellence can help them in facing these changes and achieve what they aspire to. In order to achieve research objectives, two main hypotheses have been formulated. The first hypothe
... Show MoreEmployee Stealing or internal theft is considered from the passive practices that can’t be denied or be hidden, In spite of the hospital privacy as a serving organization that works 24\7 and deleing with human lives, they weren’t infallible from that kind of practice. To prevent or reduce this practice, it was important to search for the organizational and behavioral factors influencing internal thefts. The study problem briefly is to reach the most organizational and behavioral factors influencing internal theft, in governmental hospitals in Baghdad Rusafa Health district, this was done by analyzing (20) administrative cases of thefts occurred in the District, also a sample of (60) specialist Doctor’s opinion work, in (3) hospital
... Show Morebased search on two variables two main (Administrative empowerment ) and (technical innovation) target detection relationship and influence between the five dimensions (the delegation of authority , personnel training , effective communication, work teams , motivating employees) and
(technical innovation) conducted research in General Company for electrical Industries , and through the sample included the views of managers in the various administrative levels poll .
And adopted a researcher at a major tool for data collection is questionnaire designed to find, as was the contents of the questionnaire analysis according to the Statistical Information System ( Spss), The (55) to identi
... Show MoreThis paper suggesting a new modern method to evaluate the performance of hotel industry at Jordan instead of the classical method used by the industry and that is Bench Marking , this method can be done by comparing the performance of hotel industry at two serial years which helps in calculating a standard performance .
The industry can use this standard to identify the variance, which make the evaluation of performance easier and support the efforts to develop the hotel industry at all levels and enable to give high quality services to customers.
The study believed that this situation would not be achieved unless the hotel industry will app
... Show MoreThe expansion of building blocks at the expense of agricultural land is one of the main problems causing climate change within the urban area of a city. The research came to determine these indicators, as a study was conducted on the expansion of the building blocks in three municipalities in the city of Baghdad for a period of four decades extended in the form of time cycles for the period (1981-2021) and using ArcMap GIS 10.7 technology. Then, the impact of this expansion on temperature rates was evaluated, as they are the most important climatic elements due to their significant effect on the rest of the elements. The results showed a clear, direct relationship between the increase in urban expansion rates and the corresponding r
... Show MoreInvestigations made and soil samples brought from 14 sites in different areas, including Abu Ghraib and Al Anbar. Tests and measurements made in the Microbiology Laboratory at the College of Agriculture, University of Anbar. Department of Soil Sciences and water Resources, in order to isolate bio-fertilizers and test isolates fixing nitrogen in atmosphere and solvents for phosphorous compounds efficiency. The experiment included isolating and diagnosis of bacteria from rhizosphere soils of different plants that were brought from different agricultural areas, 74 isolates obtained by soils alleviation, and then the bio-chemical morphological and microscopic characteristics of these soils studied. The results showed that the most abundant and
... Show MoreThe role and procedures for accountability in the spending units significant impact in enhancing the results of the budget it is found by studying and comparing the results of the implementation of the budget for the research sample for a period of two years to repeat the same deviations and irregularities of Guanyin, regulations and instructions that have occurred in implementation results and two consecutive Kaltjaoz customizations and low rates of implementation and the lack of exchange of allocations Finance despite the presence budget note that such remarks are always indicate in regulatory reports, but these observations repeated Bostmr in the results of the implementation of the budget. Which clearly reflects the absence of the ro
... Show MoreThe Aaliji Formation in wells (BH.52, BH.90, BH.138, and BH.188) in Bai Hassan Oil Field in Low Folded Zone northern Iraq has been studied to recognize the palaeoenvironment and sequence stratigraphic development. The formation is bounded unconformably with the underlain Shiranish Formation and the overlain Jaddala Formation. The microfacies analysis and the nature of accumulation of both planktonic and benthonic foraminifera indicate the two microfacies associations; where the first one represents deep shelf environment, which is responsible for the deposition of the Planktonic Foraminiferal Lime Wackestone Microfacies and Planktonic Foraminiferal Lime Packstone Microfacies, while the second association represents the deep-sea environme
... Show MorePurpose: Studying the activity of acid phosphatase, which is the marker of lysosomal activity in the mammary glands of rats at different stages of the physiological maturation [virgih, pregnancy, lactation and Post lactation] Methods: Forty, female, albino rats were used in this study. They were divided into four groups according to their physiological states [virgin, pregnancy, lactation and post lactation]. The mammary glands, after suitable fixation and sectioning, were employed for routine haematoxylin and eosin stain and for acid phosphatase demonstration Results: Acid phosphatase activity was weakly diffuse in the secretory tubules of virgin rats, the diffuse and granular activity of this enzyme was increased during pregnancy in the s
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