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1 - Borotellurite bio-silica glasses doped by erbium nanoparticles: Structural and thermal properties
Abdulkarim Muhammad Hamza Umar Sa'ad Aliyu Halimah Mohamed Kamari Ibrahim Gana Geidam Raouf El-Mallawany Nazrin Nazrin Muhammad Nasirudeen Baba[(TeO2)0.8 (B2O3)0.2]0.8 (SiO2)0.2}0.99 (Ag2O)0.01]1-y - (Er2O3 NPs)y, and y=0.01,0.02,0.03,0.04 and 0.05 mole% were fabricated by the melt quenching technique. X-ray diffraction (XRD) was used to verify and confirm the glasses’ non-crystallinity. X-ray fluorescen أکثر[(TeO2)0.8 (B2O3)0.2]0.8 (SiO2)0.2}0.99 (Ag2O)0.01]1-y - (Er2O3 NPs)y, and y=0.01,0.02,0.03,0.04 and 0.05 mole% were fabricated by the melt quenching technique. X-ray diffraction (XRD) was used to verify and confirm the glasses’ non-crystallinity. X-ray fluorescence (XRF) proved the achievement of silicate of 98.6% quality from rice husk. Fourier transform infrared d (FTIR) results exposed the basic structural units such as TeO4, TeO3, BO4, BO3, Si-O-Si, and O-Si-O within the network. The concentration of Er2O3 nanoparticles’ effects on the thermal properties of ErDBST glasses was duly discussed. From the profiling of the differential scanning calorimetry (DSC), the glass crystallization temperature Tc, and transition temperature Tg are estimated. Also, the thermal stability factor, defined as Ts = Tc - Tg, was higher than 100 oC. From room temperature above the Tg for all the sample glasses, specific heat capacity Cq (≥1.4 J/gK-1) was obtained. The results showed that the glass thermal stability and the transition temperature increase with the addition of Er2O3 nanoparticles (NPs). These suggest that an ErDBST glass exhibit good thermal stability and consequently is a suitable candidate for fiber drawing. تفاصيل المقالة -
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2 - Grand canonical ensemble of the extended two-site Hubbard model via a nonextensive distribution
Felipe Américo Reyes Navarro Eusebio Castor Torres-Tapia Pedro Pacheco PeñaAbstractWe hereby introduce a research about a grand canonical ensemble for the extended two-site Hubbard model, that is, we consider the intersite interaction term in addition to those of the simple Hubbard model. To calculate the thermodynamical parameters, we utilize أکثرAbstractWe hereby introduce a research about a grand canonical ensemble for the extended two-site Hubbard model, that is, we consider the intersite interaction term in addition to those of the simple Hubbard model. To calculate the thermodynamical parameters, we utilize the nonextensive statistical mechanics; specifically, we perform the simulations of magnetic internal energy, specific heat, susceptibility, and thermal mean value of the particle number operator. We found out that the addition of the intersite interaction term provokes a shifting in all the simulated curves. Furthermore, for some values of the on-site Coulombian potential, we realize that, near absolute zero, the consideration of a chemical potential varying with temperature causes a nonzero entropy.PACS75.10.Jm, 05.30.-d, 65.80.+n تفاصيل المقالة -
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3 - Synthesis and Characterization of Polyamide Containing Maleimide Pendant Group
Amir Abdolmaleki Parvin PashaieA series of new polyamides containing maleimide pendant group were prepared by low temperature polycondensation of 5-(4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamido)isophthaloyl chloride as a new monomer with various aromatic diamines in NMP. Monomer and polymers structur أکثرA series of new polyamides containing maleimide pendant group were prepared by low temperature polycondensation of 5-(4-(2,5-dioxo-2H-pyrrol-1(5H)-yl)benzamido)isophthaloyl chloride as a new monomer with various aromatic diamines in NMP. Monomer and polymers structures were identified through FT-IR, 1H-NMR and elemental analysis. Obtained polymers were soluble in polar solvents and non soluble in aprotic solvents. The inherent viscosities of the polymers have been determined in NMP and had values from 0.35 to 0.39 dL/g. Thermal stability of polymers was investigated with thermal gravimetry analysis (TGA) and diffraction scanning calorimetry (DSC). Also thermal behavior of monomer was studied with DSC analysis. X-ray diffraction measurement was used to indicate amorphous structure of polyamide تفاصيل المقالة -
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4 - مطالعۀ ابتدا به ساکن ویژگی‌های فونونی وگرمایی ترکیب GaP در دو فاز بلندروی و هگزاگونال
حمداله صالحی شیوا مخاوات پیمان امیریدر این کار ویژگی‌های فونونی ؛ گرمایی و فشار گذار ترکیب گالیم‌فسفید دردو فاز پایدار بلندروی و فاز سینابار مورد بررسی قرار می‌گیرد. محاسبات با استفاده از روش شبه پتانسیل در چارچوب نظریۀ تابعی چگالی و با استفاده از بستۀ محاسباتی کوانتوم اسپرسو صورت گرفته است.شبه پتانسیل ها أکثردر این کار ویژگی‌های فونونی ؛ گرمایی و فشار گذار ترکیب گالیم‌فسفید دردو فاز پایدار بلندروی و فاز سینابار مورد بررسی قرار می‌گیرد. محاسبات با استفاده از روش شبه پتانسیل در چارچوب نظریۀ تابعی چگالی و با استفاده از بستۀ محاسباتی کوانتوم اسپرسو صورت گرفته است.شبه پتانسیل های مورد استفاده از نوع بارپایسته بوده و برای محاسبۀ پتانسیل تبادلی-همبستگی از تقریب شیب تعمیم یافته استفاده شده است.نمودار انرژی برحسب حجم در فشار گذار نشان می دهد که فاز سینابار یک فاز شبه پایدار است. نمودار پاشندگی فونونی نشان می‌دهد که این ترکیب در فاز بلندروی دارای گافی بین cm-1 242 تا cm-1311 و در فاز سینابار فاقد گاف می‌باشد. از مطالعۀ خواص ترمودینامیکی دو فاز بلندروی و سینابار درمی‌یابیم که در هر دو فاز افت ظرفیت گرمایی در دماهای پایین، به صورت است. در دماهای بالا نیز ظرفیت گرمایی به (قانون دولن –پتی) نزدیک می‌شود. تفاصيل المقالة -
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5 - Influence of Al2O3 Additive on Mechanical Properties of Wollastonite Glass-Ceramics
Monavvar Rahimi Babak Sadeghi Maryam Kargar RaziIn this paper, wollastonite glass-ceramics and composites of wollastonite glass– ceramics with 2.5, 5, 10 and 20 weight percent alumina with an average size of 2 microns and also wollastonite glass-ceramics with 2.5, 5, and 10 percent alumina with an average size أکثرIn this paper, wollastonite glass-ceramics and composites of wollastonite glass– ceramics with 2.5, 5, 10 and 20 weight percent alumina with an average size of 2 microns and also wollastonite glass-ceramics with 2.5, 5, and 10 percent alumina with an average size of 40 nanometers were produced without pressure by Sintering and their physical properties (e.g. bulky density, the percentage of linear shrinkage and relative density) were measured. Sinter operation in the temperature range of 1030-1170 °С was performed for 3 hours. Existing phases in composites by X-ray Diffraction (XRD) and their structure were examined by Scanning Electron Microscopy (SEM) and while measuring mechanical properties of composites such as flexural strength, hardness and compared fracture toughness with base glass ceramic was performed. Results indicate that adding 2.5 percent micron-sized alumina to wollastonite glass-ceramics decreases the flexural strength from 8.01±120 to 10.26±50 MPa and its fracture toughness declines to 0.8±0.74, while by adding 2.5 percent nano-alumina to wollastonite glass – ceramics, the flexural strength increases from 8.01±120 to 20.7±133 MPa and its fracture toughness improves up to 1.40±10. تفاصيل المقالة -
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6 - Thermal and Mechanical Properties of Hybrid Composite Strengthened by Carbon Fibers/Aramid Fibers
F Basati M.H YasThis work deals with the thermal, mechanical and dynamic properties of hybrid composites reinforced with carbon fibers and aramid fibers, whose matrix is epoxy resin. In this study a series of hybrid fiber composite are prepared with carbon and aramid fibers as reinfo أکثرThis work deals with the thermal, mechanical and dynamic properties of hybrid composites reinforced with carbon fibers and aramid fibers, whose matrix is epoxy resin. In this study a series of hybrid fiber composite are prepared with carbon and aramid fibers as reinforcement. Thermal properties are obtained by thermal gravimetric analysis (TGA), Thermo-mechanical analysis (TMA) and hot plate analysis. Also mechanical properties are obtained by tensile and modal analysis tests. The experimental results are compared with the similar theoretical ones. Besides the effect of stacking sequence and hybrid ratio (adding the number of layers of carbon fibers), on the thermal and mechanical properties are investigated. The results show that by increasing the hybrid ratio although the weight of the sample is more, the thermal conductivity of the carbon fibers used is higher than that of the aramid fibers and this increase in thermal conductivity causes the heat to be transferred to the sample much faster and the temperature of the glass increases with the increase of the hybrid ratio. Due to the high stiffness of carbon fibers, adding it to the composite causes, the tensile modulus of the samples increases. By combining carbon fibers with aramid fibers, the toughness of carbon fibers can be increased and at the same time the brittle property of carbon fibers is removed due to the malleability of aramid fibers. It is concluded that aramid fiber has an effective role in improving failure strain due to its high toughness and malleability, while carbon fiber is very fragile. The lowest tensile strength occurs at the hybrid ratio of 29% with a value of 677.66 MPa. which is very close to the theoretical critical hybrid ratio. The results also show when the carbon fibers and aramid fibers are on the outer and the middle layers of the beam respectively, the frequency has a larger value because the aramid fibers have a very high impact resistance. تفاصيل المقالة -
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7 - سنتز و شناسایی کمپلکس نقره (I) شامل '4-(4-کوینولین)-2،'2:'6،''2-ترپیریدین: رفتار گرمایی، مطالعه لومینسانس و ویژگی های سمی بودن سلولی
بدری زمان مومنی ساناز کاظم زاده اناری زهرا شهسواریاز واکنش نمک نیترات نقره با '4-(4-کوینولین)-2،'2:'6،''2-ترپیریدین (qtpy) با نسبت 1:1 کمپلکس نقره (I) با عدد هم آرایی چهار و فرمول کلی (1) [Ag(qtpy)(NO3)] سنتز شد. کمپلکس به دست آمده با تجزیه عنصری، طیف سنجی فروسرخ تبدیل فوریه (FTIR)، رسانندگی مولی و طیف سنجی رزونانس مغ أکثراز واکنش نمک نیترات نقره با '4-(4-کوینولین)-2،'2:'6،''2-ترپیریدین (qtpy) با نسبت 1:1 کمپلکس نقره (I) با عدد هم آرایی چهار و فرمول کلی (1) [Ag(qtpy)(NO3)] سنتز شد. کمپلکس به دست آمده با تجزیه عنصری، طیف سنجی فروسرخ تبدیل فوریه (FTIR)، رسانندگی مولی و طیف سنجی رزونانس مغناطیسی هسته (1H,13C NMR) شناسایی شد. در طیف نشری کمپلکس 1، جابه جایی نوار مربوط به انتقال درون لیگاند *π→π به سمت طول موج‌های بلندتر نسبت به qtpy، نشان دهنده کوئوردینه شدن لیگاند به نقره است. بررسی پایداری گرمایی کمپلکس 1 با TGA نشان داد که کمپلکس تا دمای ºC 320 پایدار است. همچنین، سمی بودن سلولی کمپلکس 1 به منظور ارزیابی فعالیت پادتکثیر آن روی رده‌های سلولی گلیوبلاستوما انسانی (U-87MG)، سرطان پستان انسان (MCF-7)، سرطان تخمدان (SCOV-3)، سرطان کولون انسانی (HT-29) و فیبروبلاست‌های پوستی انسانی (AGO1522) با آزمون سمی بودن سلولی MTT بررسی شد که برای مقایسه از پاکلی‌تاکسول به عنوان مرجع استفاده شد. اثر پادسرطانی این کمپلکس بر رده سلولی گلیوبلاستوما اولیه انسانی با μM 93/6 IC50: بیشتر از داروی پاکلی تاکسول با μM38/27 IC50: است و حتی استفاده از غلظت‌های پایین کمپلکس موجب مرگ سلولی شد. تفاصيل المقالة
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