الهدف من الدراسه تحضير فئه جديده من بوليمرات السليكون P1-P4 والتي تمت على اساس استحدام ثنائي مثيل ثنائي كلورو سيلان((DCDMS مع بعض المركبات العضويه التي تحتوي مجاميع الهيدروكسيل الطرفيه والتي حضرت لاول مره M1-M4، بأستخدم البلمره التكثيفيه .كما تم تحضير متراكباتها النانويهP′1-P′4 بوجود جسيمات الفضه النانويه (Ag-NPs) باستخدام طريقة صب المحاليل. شخصت جميع التراكيب للمونمرات والبوليمرات المحضره باستخدام مطيافية FTIR و H1NMR (لبعض البوليمرات) مما سمح بتحديد المجموعات الوظيفية الفعاله للمونومرات وبوليمرات السيليكون. اجريت التحاليل الحراريه الوزنيه TGAوالمسح المسعري التفاضلي DSC لتقييم السلوك الحراري وتاثير وجود جسيمات الفضه النانويهAgNPs .اظهرت نتائج التحليل الحراري ان وجود حلقات الفنيل اظهرت استقرارحراري لبوليمرات السيليكون النقية P1-P4 وان اقحام جسيمات الفضه النانويه بوزن 7 ٪ اظهرت تحسن في الاداء الحراري للمتراكبات النانويه P′1-P′4 مقارنة ببوليمرات السليكون النقيه، ممايعني ان درجة الحراره لفقدان الوزن TGA كانت اعلى لمعظم المتراكبات النانويه P′1-P′4 مقارنة الى بوليمرات السليكون النقيه ، حيث ازدادت درجة الحراره لفقدان الوزن TGA للبوليمر P2 من 127 الى 196 للمتراكبه التانويه P′2 ،وهذا قد بعود الى ملئ الفراغات الحره بين السلاسل البوليمريه بواسطة جسيمات الفضه النانويه .استخدمت تقنية حيود الاشعه السينيه XRD لتشخيص وجود جسيمات الفضة النانويه حيث اظهرت XRD وجود الفضه بحجم نانوي يتراوح بين 20-30 نانوميتر بالاضافه الى دراسة شكل وحجم جسيمات الفضه يتقنية مجهر القوة الذريه وكما تم دراسة مورفولجية السطح باستخدام تقنية مجهر المسح الالكتروني والذي اظهرنوعا ما سطح موحد للمتراكبه النانويه.
The influence of pre- shot peening and welding parameters on mechanical and metallurgical properties of dissimilar and similar aluminum alloys AA2024-T3 and AA6061-T6 joints using friction stir welding have been studied. In this work, numbers of plates were equipped from sheet alloys in dimensions (150*50*6) mm then some of them were exposed to shot peening process before friction stir welding using steel ball having diameter 1.25 mm for period of 15 minutes. FSW joints were manufactured from plates at three welding speeds (28, 40, 56 mm/min) and welding speed 40mm/min was chosen at a rotating speed of 1400 rpm for welding the dissimilar pre- shot plates. Tow joints were made at rotational speed of 1000 rpm and welding speed of 40m/min f
... Show MoreIn this study, the effect of the thermal conductivity of phase change material (PCM) on the performance of thermal energy storage has been analyzed numerically. A horizontal concentric shell-and-tube latent heat thermal energy storage system (LHTESS) has been performed during the solidification process. Two types of paraffin wax with different melting temperatures and thermal conductivity were used as a PCM on the shell side, case1=0.265W/m.K and case2=0.311 W/m.K. Water has been used as heat transfer fluid (HTF) flow through in tube side. Ansys fluent has been used to analyze the model by taking into account phase change by the enthalpy method used to deal with phase transition. The numerical simulatio
... Show MoreIn this article, the casting method was used to prepare poly(methyl methacrylate)/hydroxyapatite (PMMA/HA) nanocomposite films incorporated with different contents (0.5, 1, and 1.5 wt%) of graphene nanoplatelets (Gnp). The chemical properties and surface morphology of the PMMA/HA blend and PMMA/HA/Gnp nanocomposite were characterized using FTIR, and SEM analysis. Besides, the thermal conductivity, dielectric and electrical properties at (1–107 Hz) of the PMMA/HA blend and PMMA/HA/Gnp composites were investigated. The structural analysis showed that the synthesized composites had a low agglomerated state, with multiple wrinkles of graphene flakes in the PMMA/HA blend. The thermal conductivity was improved by more than 35-fold its value for
... Show MoreBackground: Isoxazoles are an important class of five-membered unsaturated heterocyclic compounds. They show several applications in diverse areas such as pharmaceuticals, agrochemistry and industry. Isoxazoles are also found in natural sources showing insecticidal, plant growth regulation and pigment functions. Current study was conducted for synthesis of twenty five new Isoxazole derivatives and to evaluate the in vitro antibacterial activities of these derivatives. Methods: Benzaldoxime and their substituted [I] ae were prepared via addition-elimination reactions between aromatic aldehyde and hydroxylamine hydrochloride. In a second step, para-or meta-substituted benzaldoximes [I] ae were reacted with N-chlorosucceinimide in DMF to yield
... Show More4-amino-3-(4-(((4-hydroxy-3,5dimethoxybenzyl)oxy)methyl)phenyl)-1,2,4-triazole-5-thione was synthesized by to method the first one from melt reaction of 4-(((4-hydroxy-3,5-dimethoxybenzyl)oxy)methyl)benzoic acid with Thiocarbonyldihydrazide, the second method from convert the corresponded acid hydrazide to potassium 2-(4-(((4-hydroxy-3,5-dimethoxybenzyl)oxy)methyl)benzoyl)hydrazinecarbodithioate salt then react with hydrazine hydrate. Newly Schiff base (7a-7f) were synthesized from reaction the 4-amino-1,2,4-triazol with substituted hydroxybenzaldehyde. The resulting compounds were characterized by IR, 1H-NMR, 13C-NMR, and HRMS data. 2,2-Diphenyl-1-picrylhydrazide (DPPH) and ferric reducing antioxidant power (FRAP) assays were used to scree
... Show MoreNewly series of 6,6’-((2-(Aryl)dihydropyrimidine-1,3(2H,4H)-diyl)bis(methylene))bis(2-methoxy phenol) (3a-i) were synthesized from cyclization of 6,6’-((propane-1,3-diylbis (azanediyl)) bis(methylene)) bis(2-methoxyphenol) with several aryl aldehyde in the presence of acetic acid. The newly compounds characterized from their IR, NMR and EIMs spectra. The antioxidant capacity of these compounds screened by utilizing DPPH and FRAP assays. Compounds 3g and 3i exhibited significant antioxidant capability in both assays. Docking study for these compounds as a potential inhibitors of gyrase enzyme were carried out. Compound 3g exhibited significant inhibition with binding free energies (DG) higher than novobiocin. compounds 2, 3a, 3b, 3
... Show MoreThe formation and structural investigation of three new Mannich bases are reported. The synthesis of these compounds was accomplished via a multicomponent one-pot reaction using CaCl2 as a catalyst. The reaction of the benzaldehyde, m-bromoaniline and cyclohexanone or 4-methylcyclohexanone resulted in the formation of L1 and L3, respectively. The synthesis of L2 was achieved by mixing benzaldehyde, o-bromoaniline and cyclohexanone. The isolated compounds were characterised using a range of analytical and spectroscopic techniques. These include; NMR (1H and 13C-NMR), ESMS, FTIR, electronic spectroscopy, microanalyses and melting points. The NMR data for L1 and L2 indicated the presence of one isomer in solutions, on the NMR time scale. How
... Show MoreAbstract As a part of our ongoing project on the design and synthesis of new 4-thiazolidinone derivatives with antimicrobial activity, four new 4-thiazolidinone derivatives carrying bromo, nitro, methyl, and chloro groups on the benzene ring were synthesized by starting with the 7-amino-4-methylcoumarin moiety, linking coumarin with various phenyl isothiocynate to form the thiourea group, and then cyclizing the derivatives, characterized by IR and 1HNMR, and assayed in vitro for their antimicrobial activity against Gram positive and Gram negative bacteria and fungi. Overall, 2-(4-methyl-2-oxo-2H-chromen-3-yl)-3-(4-nitrophenyl) thiazolidin-4-one to be the most powerful individuals in the series. Based on the observed data, it can be sta
... Show More