This study aims to evaluate the melting characteristics of a phase change material (PCM) in a latent heat storage system equipped with hemispherical and quarter-spherical fins. A vertical triple-pipe heat exchanger is used as the PCM-based heat storage unit to improve the melting performance compared with a double-pipe system. Furthermore, the fins are arranged in inline and staggered configurations to improve heat transfer performance. For the quarter-spherical fins, both upward and downward directions are examined. The results of the system equipped with novel fins are compared with those without fins. Moreover, a fin is added to the heat exchanger’s base to compensate for the natural convection effect at the bottom of the heat exchanger. Considering similar fin volumes, the results show that the system equipped with four hemispherical fins on the side walls and an added fin on the bottom wall has the best performance compared with the other cases with hemispherical fins. The staggered arrangement of the fins results in a higher heat transfer rate. The downward quarter-spherical fins with a staggered configuration show the highest performance among all the studied cases. Compared with the case without fins, the heat storage rate improves by almost 78% (from 35.6 to 63.5 W), reducing the melting time by 45%.
Two decades after replacing the OAU, the AU’s record is best measured not by communiqués but by how fast it converts rules into results on the ground. In March 2022, the African Union’s Peace and Security Council (PSC) authorised the transition from AMISOM to ATMIS in Somalia — a reminder that, two decades after the African Union (AU) replaced the Organisation of African Unity (OAU), the Union’s rules are judged by execution, not intent. This article argues that the AU’s legal and institutional redesign shortened the warning‑to‑decision cycle and raised the credibility of enforcement, but performance still hinges on finance, logistics and political will. Where mandates are matched with money, enabling capabilities and enforc
... Show MoreThe investigation of determining solutions for the Diophantine equation over the Gaussian integer ring for the specific case of is discussed. The discussion includes various preliminary results later used to build the resolvent theory of the Diophantine equation studied. Our findings show the existence of infinitely many solutions. Since the analytical method used here is based on simple algebraic properties, it can be easily generalized to study the behavior and the conditions for the existence of solutions to other Diophantine equations, allowing a deeper understanding, even when no general solution is known.
Monitoring the river’s water quality is important to predict the environmental risk. The Tigris River is Baghdad’s main source for living organisms, drinking water, and agro-industrial purposes. Three selected sites were carried out using different water quality parameters from July 2017 to April 2018 in the Tigris River in Baghdad. Fourteen water quality parameters: water temperatures, turbidity, electrical conductivity, pH, calcium, magnesium, chloride, sulfate, phosphate, dissolved oxygen (DO), alkalinity, total hardness, total dissolved substances TDS, and biological oxygen demand (BOD5). According to CCME WQI analysis, the water quality of Tigris River water was Fair for aqua
Biologically active natural compounds are molecules produced by plants or plant-related microbes, such as endophytes. Many of these metabolites have a wide range of antimicrobial activities and other pharmaceutical properties. This study aimed to evaluate (in vitro) the antifungal activities of the secondary metabolites obtained from Paecilomyces sp. against the pathogenic fungus Rhizoctonia solani. The endophytic fungus Paecilomyces was isolated from Moringa oleifera leaves and cultured on potato dextrose broth for the production of the fungal metabolites. The activity of Paecilomyces filtrate against the radial growth of Rhizoctonia solani was tested by mixing the filtrate with potato dextrose agar medium at concentrations of 15%,
... Show MoreObjectives: The study aims at identifying the nurses’ knowledge about peritoneal dialysis complications, to
construct an education program for nurses in peritoneal dialysis units, to determine the effectiveness of the
education program upon the nurses' knowledge about complications of peritoneal dialysis, and to identify the
relationship between the nurses’ knowledge and their demographic characteristics of level of education and
years of experience.
Methodology: A quasi-experimentai study was carried out at the peritoneal dialysis units of Baghdad teaching
hospitals, from April 2004 to April 2006.
٨ purposive sample of (50) nurse was selected from Baghdad teaching hospitals. These nurses working at the
perit
Background: Porcelain veneers are under a great deal of stress which may lead to clinical failure as fracture or dettachment. This study examined whether different finishing lines and lingual shoulder preparations in the incisal area of the maxillary central incisor affect the bond of the porcelain veneers. Materials and methods: A two- dimensional finite element model was made. Location and magnitude of maximum Von Mises stresses were calculated in porcelain veneer. Six types of preparations were drawn as:incisal overlap of 0.5mm, 1mm and 1.5mm depth and lingual shoulder, and incisal overlap of 0.5mm, 1mm and 1.5mm depth without shoulder preparation. Results: Stress formation is maximum in the incisal edge region. All the lingual shoulder
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