The steady state laminar mixed convection and radiation through inclined rectangular duct with an interior circular tube is investigated numerically for a thermally and hydrodynamicaly fully developed flow. The two heat transfer mechanisms of convection and radiation are treated independently and simultaneously. The governing equations which used are continuity, momentum and energy equations. These equations are normalized and solved using the Vorticity-Stream function and the Body Fitted Coordinates (B.F.C) methods. The finite difference approach with the Line Successive Over-Relaxation (LSOR) method is used to obtain all the computational results. The (B.F.C) method is used to generate the grid of the problem. A computer program (Fortran 90) is built to calculate the steady state Nusselt number (Nu) for Aspect Ratio AR (0.55-1) and Geometry Ratio GR (0.1-0.9). The fluid Prandtl number is 0.7, Rayleigh number Ra = 400, Reynolds number Re = 100, Optical Thickness (0 ≤ t ≤ 10), Conduction- Radiation parameter (0 ≤ N ≤ 100) and Inclination angle λ = 45. For the range of parameters considered, results show that radiation enhance heat transfer. It is also indicated in the results that heat transfer from the surface of the circle exceeds that of the rectangular duct. Generally, Nu is increased with increasing GR, t and N but it decreased with AR increase. When the radiation effect added to the heat transfer mechanism, the heat transfer rate increased. This effect increased with increasing in GR and decreasing with AR. The increasing in radiation properties lead to increase the radiation effect. Tecplot 7 program was used to plot the curves which cleared these relations and isotherms and streamlines which illustrate the behavior of air through the channel and its variation with other parameters. A correlation equation is concluded to describe the radiation effect. Comparison of the results with the previous work shows a good agreement.
The Coronavirus Disease 2019 (COVID-19) pandemic has caused an unprecedented disruption in medical education and healthcare systems worldwide. The disease can cause life-threatening conditions and it presents challenges for medical education, as instructors must deliver lectures safely, while ensuring the integrity and continuity of the medical education process. It is therefore important to assess the usability of online learning methods, and to determine their feasibility and adequacy for medical students. We aimed to provide an overview of the situation experienced by medical students during the COVID-19 pandemic, and to determine the knowledge, attitudes, and practices of medical students regarding electronic medical education.
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Background: This in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and Methods: Metal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was confirmed using FTIR. The bonded premolars were exp
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Background: This study evaluates transdermal delivery of tamoxifen (TXN) as an alternative to the oral route of administration in treating breast cancer, which is the leading cause of cancer-related death in women globally. Oral TXN, a Class II drug, is associated with first-pass metabolism and serious side effects, including secondary cancers. Objectives: To enhance transdermal delivery, lipid-based transethosomes (TRS) were formulated using three different 24 factorial designs with various non-ionic surfactants, including Tween 20®, Span 20®, and Span 80®. Methods: Optimized TRS formulations were incorporated into HPMC-based gels and characterized for morphology, drug content, pH, viscosity, spreadability, ex vivo skin penetrat
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Synthesis of a new class of Schiff-base ligand with a tetrazole moiety to form polymeric metal complexes with CoII, NiII, ZnII, and CdII ions has been demonstrated. The ligand was synthesised by a multi-steps by treating 5-amino-2-chlorobenzonitrile and cyclohexane -1,3-dione, the 5,5'-(((1E,3E)-cyclohexane-1,3-diylidene)bis(azanylylidene))bis(2-chlorobenzonitrile) was obtained. The precursor (M) was prepared from the reaction 5,5'-(((1E,3E)-cyclohexane-1,3-diylidene)bis(azanylylidene))bis(2-chlorobenzonitrile) with NaN3 to obtained (1E,3E)-N1,N3-bis(4-chloro-3-(1H-tetrazol-5-yl)phenyl)cyclohexane-1,3-diimine (N). By reacting the precursor (M) with CS2
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In this study, the new azo dye,5,5-[1,2-phenylenebis(2,1-biazenediyl)] bis[8-quinolino], was used to synthesize complexes with Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ ions. The compounds were characterized using 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, mass spectrometry, thermo gravimetric analysis (TGA), diffevential scanning calovimltry (DSC), CHN analysis. Further, conductivity, magnetic susceptibility, and metal and chlorine content analysis using FT-IR spectroscopy revealed that the ligand chelates as a bidentate (OH) phenol group and a bidentate (C=N) ring group. The ligand exhibited tetradentate behavior, forming tetrahedral complexe
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Amid the growing demand for multifunctional and environmentally benign materials, lead-free double perovskites have emerged as a strategically important development in advanced functional materials research. This study presents the synthesis of Ba2PrMnO6 (BPMO) double perovskite nanocrystals for the first time via a hydrothermal method, and a comprehensive evaluation has been conducted using the density functional theory (DFT) framework. Structural, thermodynamic, electronic, optical, and mechanical properties were investigated through X-ray diffraction (XRD), ultraviolet-visible (UV-vis) spectroscopy, FESEM/EDX, FTIR, and density functional theory (DFT) calculations. XRD confirms a stable tetragonal I4/m phase with experimental lattice con
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This work studies developing ultrafiltration (UF) membranes using organic and inorganic additives to remove organic dyes at UF conditions with high effectiveness. Flat sheet (18 wt%) polyvinylidene fluoride (PVDF) membranes were prepared via phase inversion and then developed by adding 6 wt% polyethylene glycol (PEG) as a pore former. Furthermore, the PVDF/PEG membranes were developed by embedding tin oxide nanoparticles (SnO2 NPs) with different contents of 0.3, 0.6, and 0.9 wt%. The prepared membranes were examined for their performance in the dye removal before being characterized using the field emission scanning electron microscope, atomic force microscopy, contact angle, Fourier-transform infrared spectroscopy, surface charge,
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A series of imidazole [1,2-a] pyridine sulfonamide derivatives was designed and synthesized starting from 2-aminopyridine. In first step, 2-amino pyridine was reacted with 4-bromo phenacyl bromide in the presence of MgO leading to the afford the corresponding imidazole [1,2-a] pyridine scaffold (Panda et al., 2022 [1] ). This intermediate was subsequently subjected to chlorosulfonation using chlorosulfonic acid to afford imidazo [1,2-a] pyridine −3- sulfonyl chloride (Amer, 2009 [2] ). Thereafter, derivative (Amer, 2009 [2] ) was treated with a variety of drugs containing an amine group [4-amino-5-chloro-N-(2- (diethyl amino) ethyl) -2-methoxy benzamide, 4-amino -N-(pyridin-2-yl) benzene sulfonamide and 4-(amino methyl) cyclohexane −1-c
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