The solidification process in a multi-tube latent heat energy system is affected by the natural convection and the arrangement of heat exchanger tubes, which changes the buoyancy effect as well. In the current work, the effect of the arrangement of the tubes in a multi-tube heat exchanger was examined during the solidification process with the focus on the natural convection effects inside the phase change material (PCM). The behavior of the system was numerically analyzed using liquid fraction and energy released, as well as temperature, velocity and streamline profiles for different studied cases. The arrangement of the tubes, considering seven pipes in the symmetrical condition, are assumed at different positions in the system, including uniform distribution of the tubes as well as non-uniform distribution, i.e., tubes concentrated at the bottom, middle and the top of the PCM shell. The model was first validated compared with previous experimental work from the literature. The results show that the heat rate removal from the PCM after 16 h was 52.89 W (max) and 14.85 W (min) for the cases of uniform tube distribution and tubes concentrated at the bottom, respectively, for the proposed dimensions of the heat exchanger. The heat rate removal of the system with uniform tube distribution increases when the distance between the tubes and top of the shell reduces, and increased equal to 68.75 W due to natural convection effect. The heat release rate also reduces by increasing the temperature the tubes. The heat removal rate increases by 7.5%, and 23.7% when the temperature increases from 10 °C to 15 °C and 20 °C, respectively. This paper reveals that specific consideration to the arrangement of the tubes should be made to enhance the heat recovery process attending natural convection effects in phase change heat storage systems.
This article comprehensively examines the history, diagnosis, genetics, diversity, and treatment of SARS-CoV-2. It details the emergence of coronaviruses over the past 50 years, including the coronavirus from 2019 and its subsequent mutations, along with updated information about this virus. This review explains the development and nomenclature of coronaviruses, their cellular invasion through glycoprotein spikes binding to ACE-2 receptors, and the mechanism of cell entry via endocytosis. Diagnosis methods for COVID-19, including nucleic acid amplification, serology, and imaging techniques like chest X-ray and CT scan tests, are discussed. Treatment approaches for COVID-19 are outlined, emphasizing healthcare, antiviral medications like Rem
... Show MoreThe problem of rebellion is considered one of the features of rapid changes that a society undergoes in all spheres and directions of life, especially in the realm of social relations, customs, traditions, values, and principles. Rebellion may manifest itself in rebellion against oneself, against values or traditions, or against social or governmental authority. One may find that submission plays a vital role in all of these interactions. This study deals with the problem of rebellion in the works of two renowned authors: The French Gustave Flaubert and the Israeli Amos Oz, through two main characters who share similar qualities and traits. Emma Bovary and Henna Konin demonstrate this through their rebellion against themselves, their relati
... Show MoreThis study addresses the issue of academic writing in English by comparing pragmatic argumentation in the writing of 40 graduate students studying at Iraqi universities (SSIU) with the writing of 40 graduate students studying at American universities (SSAU). In these 80 theses, six selected aspects of academic writing were analyzed: (a) paragraph structure, (b) length and construction of sentences, (c) organization of information in sentences, (d) vocabulary, (e) topic sentences, and (f) discourse markers. This study seeks to go beyond the traditional and often onedimensional analysis of pragmatics of argumentation in English academic writing to distinguish and describe different aspects of academic writing and their results when used by EF
... Show MoreThis study was undertaken to introduce a fast, accurate, selective, simple and environment-friendly colorimetric method to determine iron (II) concentration in different lipstick brands imported or manufactured locally in Baghdad, Iraq. The samples were collected from 500-Iraqi dinars stores to establish routine tests using the spectrophotometric method and compared with a new microfluidic paper-based analytical device (µPAD) platform as an alternative to cost-effective conventional instrumentation such as Atomic Absorption Spectroscopy (AAS). This method depends on the reaction between iron (II) with iron(II) selective chelator 1, 10-phenanthroline(phen) in the presence of reducing agent hydroxylamine (HOA) and sodium acetate (NaOAc) b
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The research aimed to prepare an audit program focusing on the activities of municipal institutions related to the environmental dimension as one of the dimensions of sustainable development, and applying the program for the purpose of preparing an oversight report related to assessing the impact of the activities of municipal institutions on the environmental reality as the main channel through which municipal institutions contribute to achieving the part related to it. Among the requirements of sustainable development, the proposed program was prepared and applied to the institutions affiliated to the Directorate of Mu
... Show MoreStriae distensae SD or stretch mark are frequent skin lesion that cause considerable aesthetic concern. The 1064nm long pulsed Nd:YAG Laser has been used to promote an increase in dermal collagen and is known to be a Laser that has a high affinity to vascular chromphores. Also by using fractional CO2 Laser 10600nm as an effective modality in treatment of striae distensae SD. It works to stimulate fibroblast and enhance Collagen formation, which is important for newly generated skin tissue.
Objectives: This study aims to verify the efficacy of long pulsed Nd: YAG Laser (1064nm) in the treatment of immature striae distensae (SD) and the efficacy of C02 fractional Laser (10600nm) in treatment o
... Show MoreThis paper studies the main characteristics of the traditional urban configuration of Arab cities, as an important built heritage, discussing the approach adopted with such configuration at the local level, and examines its ability to preserve the character of the city, as well as, its responsiveness to the recent requirements of its society that constantly change; in order to reach the appropriate procedures to deal with the traditional urban configuration of the Iraqi city to achieve a vital cultural communication with the vernacular built heritage, by dealing with the Form-Moral Values structure. Due to its importance within other traditional Iraqi cities, the research chose Al-Kadhimiya as a case study, so it discusses and compares
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