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حرية الوصول المقاله
1 - بررسی تولید آراشیدونیک اسید توسط alpinaMortierella در تخمیر حالت جامد با استفاده از تفاله خرما
سیده زینب اسدی هوشنگ نیکوپور کیانوش خسروی دارانی حسین باخدامقدمه: آراشیدونیک اسیداز اسیدهای چرب ضروری چند غیر اشباع می باشد که نقش مهمی در سلامت انسان ایفا می کند. گونه هایی از قارچ جنس Mortierellaقادر به تولید گستره ی وسیعی از اسیدهای چرب چند غیراشباع به ویژه آراشیدونیک اسید بوده و تحقیقات نشان داده اند عوامل متعددی بر تولید أکثرمقدمه: آراشیدونیک اسیداز اسیدهای چرب ضروری چند غیر اشباع می باشد که نقش مهمی در سلامت انسان ایفا می کند. گونه هایی از قارچ جنس Mortierellaقادر به تولید گستره ی وسیعی از اسیدهای چرب چند غیراشباع به ویژه آراشیدونیک اسید بوده و تحقیقات نشان داده اند عوامل متعددی بر تولید آنها موثر می باشند. امروزه تولید میکروبی آراشیدونیک اسید توسط قارچ M. alpina با بکارگیری تخمیر حالت جامد مورد توجه قرار گرفته است. مواد و روش ها: تولیدآراشیدونیک اسیدتوسط کشت جدایهMortierella alpina CBS 528.72برتفاله خرما در تخمیر حالت جامد با استفاده از طرح پلاکت برمن انجام گرفت. به منظور تامین منبع نیتروژن، کنجاله سویا اضافه شد. تاثیر یازده متغیر شامل اندازه ذرات، میزان رطوبت، pH اولیه، نسبت کربن به نیتروژن سوبسترا، مکمل های روغن بزرک و سویا، سن تلقیح، دما و مدت زمان گرمخانه گذاری، مدت زمان پیش تیمار حرارتی و مکمل نیتروژن بر میزان تولید آراشیدونیک اسیددر دو سطح بررسی گردید. یافته ها: در محدوده مورد بررسی متغیرها در این تحقیق، رطوبت اولیه % 75-70 سوبسترا، افزودن w.w-1)% 10)روغن بزرک، اندازه 1/7-1/2 میلی متر ذرات سوبسترا، افزودن w.w-1)% 4 )مکمل نیتروژن و سن تلقیح 96 ساعت در افزایش تولید آراشیدونیک اسید تاثیر معنی دار داشتند. بیشترین مقدار آراشیدونیک اسید تولید شده در این تحقیق، 4/66 میلی گرم در گرم سوبسترای تخمیر شده خشک بود. نتیجه گیری: با اصلاح تفاله خرما توسط عوامل ذکر شده، می توان به تولید روغن تک یاخته حاوی بیشترین مقدار آراشیدونیک اسید توسط قارچM. alpinaدست یافت. تفاصيل المقالة -
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2 - Study of Fatigue Behavior and Microstructure of 1.6582 Steel Joint by Resistance Butt Welding
O Ashkani H .M Semnani H Sabet M .R TavighiVarious fusion welding methods can be used to create a successful jont. However, with the increase in the thickness, fusion welding processes have limitations. Therefore, solid-state welding methods have been developed and in the meantime Resistance Butt Welding method أکثرVarious fusion welding methods can be used to create a successful jont. However, with the increase in the thickness, fusion welding processes have limitations. Therefore, solid-state welding methods have been developed and in the meantime Resistance Butt Welding method has been chosen as a suitable method. In this study, joining of 1.6582 alloy steel has been investigated and analyzed, and the effect of the electric current parameter has been investigated in this welding method especially on Fatigue parameter. The results have shown this method is suitable for connecting (Joining) parts with symmetrical geometry. Also results shown that increasing the current to an optimum current leads to increasing the strength, As a result, the fatigue properties increase similarly to the strength. The noteworthy point here is that at stresses less than 220 MPa, the mentioned sample has a fatigue limit after welding, and this joint can be useful in various industries, including tool making. تفاصيل المقالة -
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3 - Effects of reaction temperature and raw material type on optical properties and crystal phase growth of Solid state synthesized NiSb2O6 nanomaterials
Alireza HakimyfardNanostructured NiSb2O6 samples were synthesized via solid state reactions at the reaction temperatures of 600, 700 and 800 °C using Sb2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O as raw materials. Parameters of reaction temperature and raw materials types were investigat أکثرNanostructured NiSb2O6 samples were synthesized via solid state reactions at the reaction temperatures of 600, 700 and 800 °C using Sb2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O as raw materials. Parameters of reaction temperature and raw materials types were investigated for the crystal phase growth study. The synthesized nanomaterials were characterized by X-ray powder diffraction (XRPD) technique, fourier-transform infrared (FTIR) spectroscopy. Brunauer–Emmett–Teller (BET) and Barrett-Joyner-Halenda (BJH) methods were used to investigate the textural properties of the obtained samples. Rietveld analyses showed that the obtained materials were crystallized well in the tetragonal crystal structure with the space group of P42/mnm. The lattice parameters of the targets were about a = b = 4.64 Å and c = 9.22 Å. The data revealed that the crystal phase purity of the as-synthesized nanomaterials was increased with increasing the reaction temperature from 600 to 800 °C. Besides, the data indicated that the synthesis reactions using Ni(NO3)2.6H2O generated a better crystalline growth and purity compared to Ni(CH3COO)2.2H2O raw material in a certain reaction temperature. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. The FESEM images showed that the homogeneity of the synthesized powder was improved when Ni(NO3)2.6H2O was used as raw material. Ultraviolet-visible spectra showed that the synthesized NiSb2O6 nanomaterials had strong light absorption in the ultraviolet light region. The calculated direct optical band gaps tendency showed that the band gaps were increased with increasing the reaction temperature. تفاصيل المقالة -
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4 - Bismuth Pyromangenate: Hydrothermal and Solid State Synthesis, Characterization and Optical Properties
Mahdi Behzad Shahin khademiniaBi2Mn2O7 nano-powders were synthesized via a stoichiometric 1:1 Bi:Mn molar ratio hydrothermal method at 180 °C for 48 h in a 1M NaOH aqueous solution; and solid state method, using Bi(NO3)3.5H2O and MnO2 as raw materials. The synthesized materials were characterize أکثرBi2Mn2O7 nano-powders were synthesized via a stoichiometric 1:1 Bi:Mn molar ratio hydrothermal method at 180 °C for 48 h in a 1M NaOH aqueous solution; and solid state method, using Bi(NO3)3.5H2O and MnO2 as raw materials. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. Also, the rietveld analysis was done in FullProf in profile matching mode. It was found that Bi2Mn2O7 crystallizes in a cubic crystal structure with space groupFd3 ̄m. The size and morphologies of the synthesized materials were studied by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) techniques, respectively. The FESEM images showed that the synthesized Bi2Mn2O7 has rod like structure in hydrothermal method and a mixture of rod and particle structures in solid state method. Also, BET-BJH analysis investigated for determination of pore size, pore volume, average particle size, pore width and surface area of the obtained materials. Also, photoluminescence spectra of the obtained materials were studied. تفاصيل المقالة -
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5 - Solid state synthesis, crystal structure, evaluation of direct and indirect band gap energies and optimization of reaction parameters for As2Ni3O8 nanomaterials
Alireza Hakimyfard shahin khademinia masumeh rahimkhaniNanostructured As2Ni3O8 samples were synthesized via facile solid state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fo أکثرNanostructured As2Ni3O8 samples were synthesized via facile solid state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The lattice parameters of the targets were about a = 5.76 Å, b = 9.54 Å and c = 10.18 Å with β = 92.95 °. It was found that nickel nitrate created a highly crystalline and pure As2Ni3O8 structure. However, nickel acetate created the target with lower purity and crystal phase growth; it produced the samples with smaller crystallite sizes. Reaction temperature changing showed that the parameter affected on the crystal growth of the obtained materials. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. Ultraviolet-visible spectra showed that the synthesized As2Ni3O8 nanomaterials had strong light absorption in the ultraviolet - visible light region. The direct optical band gaps were 2.6 and 2.5 eV for S1 and S3, respectively. The data showed that the band gaps were decreased by increasing the reaction temperature. This is due to the increasing the crystallite sizes of the obtained materials. تفاصيل المقالة -
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6 - High efficient solar light photocatalytic degradation of malachite green by solid state synthesized Bi2Sn2O7 and Bi2MxSn2O7 ﴾M = Y3+, Eu3+, Gd3+ and Yb3+) nanomaterials
Ladan Roohandeh Alireza Hakimyfard Mohammad SamimifarNanostructured Bi2Sn2O7 and Bi2MxSn2O7 ﴾M = Y3+, Eu3+, Gd3+ and Yb3+) nanomaterials were synthesized by conventional one-step solid state crystal growth reactions among Bi(NO3)3, SnCl2 and M2O3 raw materials at 800 ̊C for 10 and 15 h. The doped nanomaterials were synthe أکثرNanostructured Bi2Sn2O7 and Bi2MxSn2O7 ﴾M = Y3+, Eu3+, Gd3+ and Yb3+) nanomaterials were synthesized by conventional one-step solid state crystal growth reactions among Bi(NO3)3, SnCl2 and M2O3 raw materials at 800 ̊C for 10 and 15 h. The doped nanomaterials were synthesized to study the capacity of the crystal system to locate each of the dopant ions into the crystal system cavities. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique. Rietveld analysis showed that the obtained materials were crystallized well in orthorhombic crystal structure with the space group Aba2. The PXRD data revealed that dopant ion type had a considerable influence on the crystal phase purity of the obtained targets. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. Ultraviolet-visible spectra analysis showed that the synthesized nanomaterials had strong light absorption in the ultraviolet light region. Photocatalytic performance of the synthesized nanomaterials was investigated for the degradation of pollutant Malachite Green under solar light condition. The optimum conditions were modeled and obtained by design expert software for Bi2Sn2O7 that was synthesized at 800 ̊C for 10 h which were 0.06 mL H2O2, 12 mg catalyst and 40 min for the removal of 50 mL of 40 ppm MG solution. The degradation yield in these conditions was 100 %. The photocatalytic degradation fitted to the Langmuir–Hinshelwood kinetic model. As a result of the model, the kinetic of degradation followed a pseudo-zero-order kinetic model. تفاصيل المقالة -
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7 - Solid state synthesis, crystal structure, evaluation of direct and indirect band gap energies and optimization of reaction parameters for As2Ni3O8 nanomaterials
Alireza Hakimyfard Shahin Khademinia Masumeh RahimkhaniNanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique an أکثرNanostructured As2Ni3O8 samples were synthesized via facile solid-state reactions at 850 and 950 °C for 8h using As2O3, Ni(CH3COO)2.2H2O and Ni(NO3)2.6H2O raw materials. The synthesized nanomaterials were characterized by powder X-ray diffraction (PXRD) technique and fourier-transform infrared (FTIR) spectroscopy. The rietveld analyses showed that the obtained materials were crystallized well in monoclinic crystal structure with the space group P121/c1. The lattice parameters of the targets were about a = 5.76 Å, b = 9.54 Å and c = 10.18 Å with β = 92.95 °. It was found that nickel nitrate created a highly crystalline and pure As2Ni3O8 structure. However, nickel acetate created the target with lower purity and crystal phase growth; it produced the samples with smaller crystallite sizes. Reaction temperature changing showed that the parameter affected on the crystal growth of the obtained materials. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) technique. Ultraviolet-visible spectra showed that the synthesized As2Ni3O8 nanomaterials had strong light absorption in the ultraviolet-visible light region. The direct optical band gaps were 2.6 and 2.5 eV for S1 and S3, respectively. The data showed that the band gaps were decreased by increasing the reaction temperature. This is due to the increasing the crystallite sizes of the obtained materials. تفاصيل المقالة -
حرية الوصول المقاله
8 - High efficient solar light photocatalytic degradation of malachite green by solid state synthesized Bi2Sn2O7 and Bi2MxSn2O7 (M = Y3+, Eu3+, Gd3+ and Yb3+) nanomaterials
hassan GHEISARI Ebrahim Karamian Ali SoheilyNanostructured Bi2Sn2O7 and Bi2MxSn2O7 (M = Y3+, Eu3+, Gd3+ and Yb3+)nanomaterials were synthesized by conventional one-step solid state crystalgrowth reactions among Bi(NO3)3, SnCl2 and M2O3 raw materials at 800 ̊C for 10and 15 h. The doped nanomaterials were synthesiz أکثرNanostructured Bi2Sn2O7 and Bi2MxSn2O7 (M = Y3+, Eu3+, Gd3+ and Yb3+)nanomaterials were synthesized by conventional one-step solid state crystalgrowth reactions among Bi(NO3)3, SnCl2 and M2O3 raw materials at 800 ̊C for 10and 15 h. The doped nanomaterials were synthesized to study the capacity of thecrystal system to locate each of the dopant ions into the crystal system cavities.The synthesized nanomaterials were characterized by powder X-ray diffraction(PXRD) technique. Rietveld analysis showed that the obtained materials werecrystallized well in orthorhombic crystal structure with the space group Aba2.The PXRD data revealed that dopant ion type had a considerable influence on thecrystal phase purity of the obtained targets. The morphologies of the synthesizedmaterials were studied by field emission scanning electron microscopy (FESEM)technique. Ultraviolet-visible spectra analysis showed that the synthesizednanomaterials had strong light absorption in the ultraviolet light region.Photocatalytic performance of the synthesized nanomaterials was investigatedfor the degradation of pollutant Malachite Green under solar light condition. Theoptimum conditions were modeled and obtained by design expert software forBi2Sn2O7 that was synthesized at 800 ̊C for 10 h which were 0.06 mL H2O2, 12mg catalyst and 40 min for the removal of 50 mL of 40 ppm MG solution. Thedegradation yield in these conditions was 100 %. The photocatalytic degradationfitted to the Langmuir–Hinshelwood kinetic model. As a result of the model, thekinetic of degradation followed a pseudo-zero-order kinetic model. تفاصيل المقالة -
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9 - مدل‌سازی چگالی حامل‌های بار در سلول خورشیدی نانوساختاری حالت جامد حساس شده با رنگدانه
تهمینه جلالی مرتضی صادقی شهریار عصفوریسلولهای خورشیدی حساس شده با رنگدانه نسل جدیدتری از سلول‌های خورشیدی هستند که اگرچه بازده پایین‌تری نسبت به سلول‌های سیلیکونی دارند، اما پتانسیل بالایی برای بازده بیشتر دارند و چون از نظر اقتصادی صرفه بهتری دارند، اگر بازده و پایداری آنها افزایش یابد می‌توانند جایگزین أکثرسلولهای خورشیدی حساس شده با رنگدانه نسل جدیدتری از سلول‌های خورشیدی هستند که اگرچه بازده پایین‌تری نسبت به سلول‌های سیلیکونی دارند، اما پتانسیل بالایی برای بازده بیشتر دارند و چون از نظر اقتصادی صرفه بهتری دارند، اگر بازده و پایداری آنها افزایش یابد می‌توانند جایگزین سلول‌های خورشیدی سیلیکونی در بازار شوند. طراحی و توسعه روزافزون سلول‌های خورشیدی تنها محدود به کارهای تجربی و آزمایشگاهی نبوده، بلکه مدلسازی‌های عددی نیز در این امر دخیل بوده است. هدف از انجام این تحقیق طراحی و مدل‌سازی عددی سلول¬های خورشیدی حالت جامد حساس شده با رنگدانه بر پایه لایه نانوساختار نیمرسانا با گاف نواری عریض (دی-اکسیدتیتانیوم) و همچنین اکسید روی به عنوان انتقال دهنده الکترون و رنگدانه N719 به عنوان لایه جاذب و همچنین PEDOT:PSS و P3HT به عنوان ماده انتقال دهنده حفره است. در این پژوهش از نرم افزار کامسول برای طراحی سلول خورشیدی استفاده و مشخصه‌های جریان-ولتاژ و همچنین جذب اپتیکی سلول محاسبه شده است که با داده‌های تجربی مطابقت خوبی دارد. تفاصيل المقالة -
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10 - سنتز پودر هگزا آلومینات لانتانیم (LaMgAl11O19) به منظور پوشش دهی به روش پلاسما اسپری بر روی سوپر آلیاژ پایه نیکل به عنوان پوشش سد حرارتی
محمد مهدی خرمی راد محمد رضا رحیمی پور سید محمد مهدی هادوی کوروش شیروانی جوزانیهگزاآلومینات لانتانیم(LaMgAl11O19) به عنوان یک پوشش سد حرارتی جدید به دلیل خواص و ویژگی های برتر، جایگزین مناسبی برای زیرکونیای پایدارشده با ایتریا( YSZ) می باشد. در این پژوهش ابتدا به سنتز پودر به روش حالت جامد و سپس به بررسی و فرآوری آن جهت انجام پوشش دهی پلاسما اسپری أکثرهگزاآلومینات لانتانیم(LaMgAl11O19) به عنوان یک پوشش سد حرارتی جدید به دلیل خواص و ویژگی های برتر، جایگزین مناسبی برای زیرکونیای پایدارشده با ایتریا( YSZ) می باشد. در این پژوهش ابتدا به سنتز پودر به روش حالت جامد و سپس به بررسی و فرآوری آن جهت انجام پوشش دهی پلاسما اسپری پرداخته شد. جهت ارزیابی خواص پودر سنتز شده از میکروسکوپ الکترونی، الگوی پراش اشعه ایکس و آنالیز حرارتی استفاده شد. برای سنتز هگزا آلومینات لانتانیم، ابتدا از α-Al2O3 به عنوان مواد اولیه استفاده شد که نتایج نشان دهنده عدم تشکیل فاز مورد نظر بود. سپس از پودر -Al2O3γ استفاده شد که در نتیجه آن ترکیبی به صورت تکفاز با مورفولوژی صفحه ای تشکیل شد و همچنین دمای سنتز این ترکیب Cº1330 تعیین گردید. در محدوده دمای Cº1100-850 ترکیبات LaAlO3، MgAl2O3 و α-Al2O3 تشکیل گردیدند که استحاله فاز نهایی ناشی از واکنش این سه ترکیب می باشد. از نتایج آنالیز فازی می توان نتیجه گرفت که نقش اصلی فاز-Al2O3γ، کاهش دمای سنتز فاز اسپینل MgAl2O4 در دمایی کمتر از Cº 1100 می باشد. آنالیز شیمیایی پودرهای گرانول شده و پوشش اعمالی به روش پلاسما اسپری تحت پارامترهای بهینه سازی شده، حاکی از وجود یک سیستم تکفاز و عدم تجزیه ترکیب می باشد. تفاصيل المقالة
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