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 the research is to clarify the role of service quality through its dimensions represented by (tangibility, reliability, safety, response, empathy) in tax compliance with taxpayers, i.e. performance of the duties and obligations of the taxpayer through its dimensions (registration, accounting, payment of the amount of tax), and to know For this role, a sample was taken from the taxpayers of the branches of the General Authority for Taxes spread in the governorate of Baghdad and its affiliated districts, which amount to (15) tax branches, as (215) questionnaires were distributed to know the impressions and reactions of the taxpayers regarding the level of service quality through the aforementioned dimensions. Using the statistic
... Show MoreA simple, rapid and sensitive spectrophotometirc method for the determination of trace amounts of promethazine hydrochloride in the aqueous solution is described. The method is based on the complexation of promethazine hydrochloride with In (III) in the presence of sodium hydroxide to form an soluble product with maximum absorption at 304nm. Beer’s law is obeyed over the concentration range of (2- 20μg/ml) with molar absorptivity of (1.92× 103 L.mol-1 .cm -1 ). The optimum conditions for all development are described and the proposed method has been successfully applied for the determination of promethazine hydrochloride in bulk drug.
Bleeding disorders in pediatrics is an important issue and can be lifethreatening if not diagnosed and treated appropriately. We aimed to evaluate Iraqi pediatric practice (as an example of resource-limited settings) about the use of Recombinant Activated Factor VII (RFVIIa) in bleeding disorders, with emphasis on its effectiveness and safety, in comparison with adjuvant therapy. Budget restrictions may affect the availability of even lifesaving drugs such as (RFVIIa). Therefore, we tried to investigate the local experience of pediatric bleeding, with the evaluation of the potential ability of adjuvant therapy of blood products and vitamin K to substitute RFVIIa in case of non-availability. During a complete one year‘s period, 35 patients
... Show MoreThe aim of this research is to find out why some matrix verbs are no longer complemented by the two types of infinitive clauses as it is the case in Elizabethan English . At that time (when Shakespeare was writing ), the same matrix verb triggers the two types of infinitive clauses as its complex transitive complementation .Such free variation is not possible in Present –Day English . In this corpus – based study , it is shown that the choice of the form of the infinitive clause is not free; there are certain syntactic ,sem- antic constraints that dete, - infinitive.
Abstract: The term extremism refers to the distance from moderation, excess and hyperbole, and it is a relative term that varies from one society to another, according to the prevailing traditions, values and culture, as the problem of extremism is one of the main issues that contemporary societies are concerned with is a phenomenon that has its roots in the intellectual formation of societies. By knowing the concept of extremism, we can identify the reasons that contributed to the existence of extremism as a phenomenon, on the one hand; on the other hand, to clarify the role of women in combating extremism and developing effective solutions to reduce this phenomenon. As women play a major role in society, starting from the family to educa
... Show MoreOut of 180 children, 60 (33.3%) have Amoebiasis infection as diagnosed by direct wet smear and Saturated Salt Solution (SSS). SSS method is more significant (P=0.001) in diagnosis of the disease. Number of children infected with Amoebiasis infection is higher in infants aged 1-6 months, but without any significant difference to ages 6-12 or 12-18 months. In contrast, infants aged 18-24 months are significantly differant (P=0.01) as the infection rate is 16.6%. Gender also is seen to be reduced in significance (P= 0.001) for females aged 18-24 months. Blood profile of the involved infants has shown a significant variation (P=0. 01) for all blood profile parameters (RBC (P=0.05), WBC (P=0.001), Lymphocytes (P=0.05), Granulated WBC (P=0.05),
... Show MoreThe rotation effect upon Morse potential had been studied and the values of the effective potential in potential curves had been calculated for electronic states (X2?+g , B ?u ) K2 molecule. The calculation had been computed for rotational quantum number (J = 5). Also, drawing potential curves for these systems had been done using Herzberg and Gaydon equations. It was found that the values of the dissociation energy which resulting from using Herzberg equation greater than that of Gaydon equation. Besides, it was found that the rotation effect for (X and B) electronic states in Morse potential is very small and in this case may negligible.
The simulation is the oldest theory in art, since it appeared in the Greek aesthetic thought of the philosopher Plato, as we find in many of the thinkers and philosophers over a wide period of time to reach our world today. Our fascination with art in general and design art in particular is due to the creativity and innovations of the artist through the simulation, as well as the peculiarities in this simulation, which give objects signs and signals that may have an echo that sometimes does not exist in their physical reality.
The real representation of life and design construction, descriptions of the expression of each of them in the form of intellectual construction and the ideas of producti
... Show More<p>There is an Increasing demand for the education in the field of E-learning specially the higher education, and to keep contiuity between the user and the course director in any place and time. This research presents a proposed and simulation multimedia network design for distance learning utilizing ATM technique. The propsed framework determines the principle of ATM technology and shows how multimedia can be integrated within E- learning conteext. The first part of this research presents a theoretical design for the Electricity Department, university of technology. The purpose is to illustrate the usage of the ATM and Multimedia in distance learning process. In addition, this research composes two entities: Software entity
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