واحدة من أكثر مواد السيراميك الهيكلية الواعدة هي كربيد السيليكون(SiC) ، حيث له خصائص حرارية وكهروميكانيكية ممتازة. هذه الخصائص مفيدة ل CMC لتعزيز أداء المركب خاصة عند إضافات النانو المتكاملة. في هذا البحث, تم تصنيع مركب SiC من SiC بثلاثة تركيزات مع ZnO و Si. تم اختبار الخواص المغناطيسية لجميع المخاليط باستخدام مراقبة العينة الاهتزازية (VSM). تم تلبيد العينات الخضراء في فرن التلبيد عند 1600 درجة مئوية في بيئة النيتروجين. تم اختبار جميع المركبات التي تم الحصول عليها وتوصيفها باستخدام تقنيات و توصيفات مختلفة مثل حيود الأشعة السينية، ومورفولوجيا السطح تمت باستخدام FESEM، ومحلل الشبكة لاختبار الخصائص العازلة للعينات. بناء على بيئة التلبيد، تم اكتشاف نيتريد السيليكون في المركب بسبب عملية النتردة على طول المركب. من ناحية أخرى، تم حساب الخصائص المغناطيسية والامتصاصية لجميع مركبات SiC. تعتبر الخصائص العازلة عالية حيث يميل المركب إلى أن يكون عاكسا في نطاق التردد المنخفض و نافذ كلما زاد التردد على طول نطاق التردد.
In this study three inorganic nano additives, namely; CaCO3, Al2O3 and SiO2 were used to prepare nanocomposites of unsaturated polyester in order to modify their mechanical properties, i.e. tensile strength, elongation, impact and hardness. The results indicated that all the three additives were effective to improve the mechanical properties up to 4% by weight. The effectiveness of them follows the order : CaCO3 > Al2O3 > SiO2 This is due to their particle size in which CaCO3 (13nm), Al2O3 (20-30nm) and SiO2 (15-20nm).
This thesis aims to study the effect of addition polymer materials on mechanical properties of self-compacting concrete, and also to assess the influence of petroleum products (kerosene and gas oil) on mechanical properties of polymer modified self-compacting concrete (PMSCC) after different exposure periods of (30 ,60 ,90 ,and 180 days).
Two type of curing are used; 28 days in water for SCC and 2 days in water followed 26 days in air for PMSCC.
The test results show that the PMSCC (15% P/C ratio) which is exposed to oil products recorded a lower deterioration in compressive strength's values than reference concrete. The percentages of reduction in compressive strength values of PMSCC (15% P/C ratio) was
... Show MoreThe D.C electrical and thermoelectrically properties of randomly mixed isolator – electrolyte system as (Al/ PVC – LiF/Al) junction consisting of polyvinyl chloride (PVC)resin reinforced with Lithium Fluoride (LiF) powder were studied. A comparison is made the properties of (PVC) material with varying percentage of (LiF) powder (0%, 30%, 50%, 80%)to find out the effect of reinforcement of isolator material. The composites dissolving in 10ml form tettraHaedroflourn (THF) and Solution were the castled in Petri dish and Laved it dry in the air, The out coming Sample were disc - Like shape of a diameter of about 3cm and thickness reneged between (0.01- 0.018) cm . The composites dissolving in 10ml form tettraHaedroflourn (THF) a
... Show MoreRare earth elements (Cerium, Lanthanum and Neodymium) doped CdS thin films are prepared using the chemical Spray Pyrolysis Method with temperature 200 oC. The X-ray diffraction (XRD) analysis refers that pure CdS and CdS:Ce, CdS:La and CdS:Nd thin films showed the hexagonal crystalline phase. The crystallite size determined by the Debye-Scherrer equation and the range was (35.8– 23.76 nm), and it was confirmed by field emission scanning electron microscopy (FE-SEM). The pure and doped CdS shows a direct band gap (2.57 to 2.72 eV), which was obtained by transmittance. The room-temperature photoluminescence of pure and doped CdS shows large peak at 431 nm, and two small peaks at (530 and 610 nm). The Current – voltage measurement in da
... Show MoreIn the current study, the definition of mapping of fuzzy neutrosophic generalized semi-continuous and fuzzy neutrosophic alpha has generalized mapping as continuous. The study confirmed some theorems regarding such a concept. In the following, it has been found relationships among fuzzy neutrosophic alpha generalized mapping as continuous, fuzzy neutrosophic mapping as continuous, fuzzy neutrosophic alpha mapping as continuous, fuzzy neutrosophic generalized semi mapping as continuous, fuzzy neutrosophic pre mapping as continuous and fuzzy neutrosophic γ mapping as continuous.
CdS and CdS:Sn thin films were successfully deposited on glass
substrates by spray pyrolysis method. The films were grown at
substrate temperatures 300 C°. The effects of Sn concentration on the
structural and optical properties were studied.
The XRD profiles showed that the films are polycrystalline with
hexagonal structure grown preferentially along the (002) axis. The
optical studies exhibit direct allowed transition. Energy band gap
vary from 3.2 to 2.7 eV.
Four Se70Ge20Sb10 alloy samples were prepared using the melt quenching technique. To improve the energy states of the mobility gap, the samples were exposed to gamma radiation from 60Co source at various doses of 600, 1200, 1500, and 2000 Gy. The electrical characteristics were examined both before and after irradiation. The conductivity analysis revealed that all of our samples were impacted by gamma radiation. The reorganization of the amorphous lattice and the degree of radiation-induced disorder have been involved in the changes that occurred in the electrical characteristics of the irradiated samples. All irradiated and non-irradiated samples feature three conduction mechanisms at low temperatures, where the electrical conducti
... Show MoreThe importance of specifying proper aggregate grading for achieving satisfactory performance in pavement applications has long been recognized. To improve the specifications for superior performance, there is a need to understand how differences in aggregate gradations within the acceptable limits may affect unbound aggregate base behavior. The effects of gradation on strength, modulus, and deformation characteristics of high-quality crushed rock base materials are described here. Two crushed rock types commonly used in constructing heavy-duty granular base layers in the State of Victoria, Australia, with three different gradations each were used in this study. The gradations used represent the lower, medium, and upper gradation li
... Show MoreThe thin films of SnO2,SnO2:TiO2 , SnO2:MoO3 , SnO2:WO3 , SnO2:Cr2O3 , and SnO2: Fe2O3 were prepared by pulsed laser deposition technique using (Nd:YAG) laser of λ=1064 nm average frequency (6) Hz and pulse duration (10 ns) under vacuum of 10 -2 mbar)deposited on glass, n-Si single crystals substrate room temperature with thickness of (100±10) nm. The structures of pure SnO2 and ,SnO2:TiO2 , SnO2:MoO3 , SnO2:WO3 , SnO2:Cr2O3 , SnO2:Co3O4 compounds were studied by X–ray diffraction .the results showed that there was red shift accompanied addition of MoO3 and TiO2 while a blue shift accompanied the addition of WoO3 , Cr2O3 , Fe2O3 to tin oxide . The gas sensing measurements of NO2 gas showed that S
... Show MoreCocrystallization is an emerging approach for improving physico-chemical characteristics of an active pharmaceutical ingredient (API) for instance dissolution rate, solubility, stability in addition to mechanical properties without affecting their therapeutic activity. It is of great importance when other approaches like salt or polymorph formation do not encounter the estimated targets. In this review article, an outline of pharmaceutical cocrystals will be presented, with highlighting on factors affecting cocrystallization which include ∆pKa, donors and acceptors hydrogen bonds, molecular recognition point, synthon forming functional groups flexibility, dicarboxylic acid coformers carbon chain length and solvent effe
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