Phase change material (PCM) is considered as one of the most effective thermal energy storage (TES) systems to balance energy supply and demand. A key challenge in designing efficient PCM-based TES systems lies in the enhancement of heat transmission during phase transition. This study numerically examines the privilege of employing twisted-fin arrays inside a shell-and-tube latent heat storage unit to improve the solidification performance. The presence of twisted fins contributes to the dominating role of heat conduction by their curved shapes, which restricts the role of natural convection but largely aids the overall heat-transfer process during solidification. The heat-discharge rate of twisted-fin configuration is increased by ∼14 and ∼55% compared to straight fin and no fin configurations—leading to a reduction in the solidification duration by ∼13 and ∼35%, respectively. The solidification front at various times has also been assessed through a detailed parametric study over the fin height, fin pitch number, and fin thickness. Over the range of values assumed, the fin height is the most dominant parameter – increasing the heat-retrieval rate from 10.0 to 11.4 W and decreasing the discharge time from above 3600 to 2880 s by varying the fin height from 2.5 to 7.5 mm.
Background: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center of t
... Show MoreBackground: Poly-ether-ether-ketone(PEEK) has been introduced to many dental fields. Recently it was tested as a retainer wire‎ following orthodontic treatment. This study aimed to investigate the effect of changing the bonding spot size and location on the performance of PEEK retainer wires. Methods: A biomechanical study involving four three-dimensional finite element models was performed. The basic model was with a 0.8 mm cylindrical cross-section PEEK wire, bonded at the center of the lingual surface of the mandibular incisors with 4 mm in diameter composite spots. Two other models were designed with 3 mm and 5 mm composite sizes. The last model was created with the composite bonding spot of the canine away from the center
... Show MoreThe shape dimensions and characteristics of pollen grains and seeds have importance in distinguish among species. Therefore, the present study included morphological characteristics of pollen grains and seeds for eight species belonging to eight genera of the family Brassicaceae and these species are: Alliaria petiolata (M.Bieb) Cavara et Grand, Aubrieta parviflora Boiss, Cardamine hirsuta L., Crambe orientalis L., Eromobium aegyptiacum (Spreng.) Schweinf.et Asch.ex Boiss., Parlatoria cakiloidea Boiss., Sterigmostemum sulphureum (Banksetsol.) Bornm. Neotorularia torulosa (Desf.) Hedge & J. Leonard. The pollen grains were studied in morphological and full measurements were taken, the study showed that the majority of the pollen grai
... Show MoreSliding Mode Controller (SMC) is a simple method and powerful technique to design a robust controller for nonlinear systems. It is an effective tool with acceptable performance. The major drawback is a classical Sliding Mode controller suffers from the chattering phenomenon which causes undesirable zigzag motion along the sliding surface. To overcome the snag of this classical approach, many methods were proposed and implemented. In this work, a Fuzzy controller was added to classical Sliding Mode controller in order to reduce the impact chattering problem. The new structure is called Sliding Mode Fuzzy controller (SMFC) which will also improve the properties and performance of the classical Sliding Mode control
... Show MoreObjective: The objective of this study was to prepare nanosuspension of a practical water insoluble antiulcer drug which is lafutidine to enhance the solubility, dissolution rate with studying the effect of different formulation variables to obtain the best formula with appropriate physical properties and higher dissolution rate.Methods: Nanosuspension of lafutidine was prepared using solvent anti-solvent precipitation method using Polyvinylpyrrolidone K-90(PVP K-90) as the stabilizer. Ten formulations were prepared to show the effect of different variables in which two formulations showed the effect of stabilizer type, three formulations showed the effect of stabilizer concentration, two formulations showed the effect of combinatio
... Show MoreMotifs template is the input for many bioinformatics systems such codons finding, transcription, transaction, sequential pattern miner, and bioinformatics databases analysis. The size of motifs arranged from one base up to several Mega bases, therefore, the typing errors increase according to the size of motifs. In addition, when the structures motifs are submitted to bioinformatics systems, the specifications of motifs components are required, i.e. the simple motifs, gaps, and the lower bound and upper bound of each gap. The motifs can be of DNA, RNA, or Protein. In this research, a motif parser and visualization module is designed depending on a proposed a context free grammar, CFG, and colors human recognition system. GFC describes the m
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The prevalence of gastrointestinal symptoms of COVID-19 is variable with different types of presentations. Some of them many present with manifestations mimicking surgical emergencies. Yet, the pathophysiology of acute abdomen in the context of COVID-19 remains unclear. We present a case of a previously healthy child who presented with acute appendicitis with multisystemic inflammatory syndrome. We also highlight the necessity of considering the gastrointestinal symptoms of COVID-19 infection in pediatric patients in order to avoid misdiagnosis and further complications. |
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The study aimed to test the hypothesis of Caldor to estimate the relationship between industrial production and GDP growth in Iraq using with Integration Framework and to determine the causal relationship in the short and long term using the error correction vector model for the period 1990-2016. the results showed a long-term equilibrium relationship between GDP and industrial output, while Ganger causality tests showed a causal relationship in the long run of GDP to output Subliminal thus illustrated the extent of the recession suffered by the industrial sector, which is supposed to be the driving force of the economy and the development and expansion of the productive base of the industry, so this study recommends attent
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