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.
Various visual media are becoming an increasingly important and active instrument of communication. This fact has led some political parties and leading personalities in Iraq to make use of them as an accepted forum for the discussion of public affairs usually in a manner that conforms to their declared policy. They have to draw as much popular support as they could for the causes which they fight for. As a result, a state of great confusion has been created from the contradictory statements made by the contending parties and gave left grave consequences on all types of the audience receiving them. The problem of the study can be summarized in one major question: What is the opinions of the audience as regards the statements made by the
... Show MoreThis study aims to highlight the role of strategic leadership in adopting the intelligent organization model. The study was conducted on 7 economic organizations in Algeria. The study population consisted of 354 leaders, of whom a random sample of 176 leaders (managers, department heads, division heads, engineers) was selected. The researcher used a questionnaire as the main tool of the study. Statistical analysis and hypothesis testing were conducted using SEM (Structural Equation Modeling) with the aid of SPSS.v26 and AMOS.v24 software. The study concluded with a set of results, most notably: there is a statistically significant direct positive effect between strategic leadership and building intelligent organizations at a significance le
... Show MoreCongenital absence of anterior cruciate ligament is highly uncommon occurrence. It has since been documented as a standalone anatomical entity or, more frequently, in conjunction with other congenital anomalies. Surgical treatment for this patient population has only been reported in very few cases. In this article, we share our experience in managing a case of unilateral congenital deficiency of anterior cruciate ligament (ACL) in a 13 years old female patient by physeal sparing arthroscopic ACL reconstruction, using All-inside technique.
True random number generators are essential components for communications to be conconfidentially secured. In this paper a new method is proposed to generate random sequences of numbers based on the difference of the arrival times of photons detected in a coincidence window between two single-photon counting modules
Since cancer is becoming a leading cause of death worldwide, efforts should be concentrated on understanding its underlying biological alterations that would be utilized in disease management, especially prevention strategies. Within this context, multiple bodies of evidence have highlighted leptin’s practical and promising role, a peptide hormone extracted from adipose and fatty tissues with other adipokines, in promoting the proliferation, migration, and metastatic invasion of breast carcinoma cells. Excessive blood leptin levels and hyperleptinemia increase body fat content and stimulate appetite. Also, high leptin level is believed to be associated with several conditions, including overeating, emotional stress, inflammation, obesity,
... Show MoreThe research addressed an analytical field investigation of the locality of meander, the factors responsible of the locality of the meander at certain points of the stream other than others, and the role sequence of these factors in the formation process.
The research revealed that the location of forming the meander was associated closely with the scale structural composition of the bank materials from which the first stage of forming the curved stream, for the inhomogeneous or non-identical opposite banks in their scale structural composition saw an activity of differential corrosion, while the homogeneous and identical opposite banks in their scale structural composition saw an identical corrosion activity in its intensity at both
Naber and toning in the modern Arab poetry Mahmoud Darwish, a model
Praise be to God, prayer, and peace be upon the Messenger of Allah and his God and his companions. The field of the judiciary to prove or invalidate some cases in the field of proof of descent and attachment to the plaintiff or exile, and other legal and judicial issues, especially in this era where the spread of previously unknown evidence, such as DNA, which was discovered in 1953, and the genetic fingerprint discovered 1984, blood analysis and a Saliva, sweat, poetry, etc. in the field of forensic evidence, in forensic medicine or medical expertise, it can be used to identify the killer, or verify his identity, using all the evidence in the scene, such as a point of blood or sweat, and the like So, as well as to prove the lineage is u
... Show MoreThe aim of this paper is to introduce the concept of N and Nβ -closed sets in terms of neutrosophic topological spaces. Some of its properties are also discussed.