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حرية الوصول المقاله
1 - Investigation of nitrogen plasma effect on the nonlinear optical properties of PMMA
Davoud Dorranian Yasaman Golian Alireza HojabriAbstract Effects of low power direct current nitrogen plasma on linear and nonlinear optical properties of red BS dye-doped poly(methyl methacrylate) (PMMA) film are studied employing different optical techniques. From spectrometry data, it is shown that applying plasma أکثرAbstract Effects of low power direct current nitrogen plasma on linear and nonlinear optical properties of red BS dye-doped poly(methyl methacrylate) (PMMA) film are studied employing different optical techniques. From spectrometry data, it is shown that applying plasma in such a low range of power does not affect the linear absorption coefficient, linear refractive index, and optical bandgap of this dye-doped polymer; however, nonlinear parameters are changed. Experiments are performed using the second harmonic of a continuous Nd-Yag laser beam at a 532-nm wavelength and 20-mW power. The effect of nonlinear refractive index of red BS dye-doped PMMA film in broadening the laser beam is observed. The optical bleaching behavior is investigated by measurement of the intensity of laser beam through the sample. Its third-order nonlinearity is measured using close and open Z-scan data. Nonlinear absorption coefficient and refractive index, as well as real and imaginary parts of the third-order nonlinear optical susceptibility χ3, are changed significantly due to plasma treatment. PACS: 42.65.-k: 42.65.An: 42.70.Jk: 61.41. + e: 71.35.Cc. تفاصيل المقالة -
حرية الوصول المقاله
2 - بررسی میزان ترکیبات فنلی در انواع شکر حاصل از مراحل مختلف فرایند کریستالیزاسیون طی 2 سال نگهداری
مسعود هنرور فاطمه سید سجادی احمد کلباسی اشتری کامبیز لاریجانی بابک دلخوش پرنیان متقیانمقدمه:شکر به عنوان یک ماده غذایی پر مصرف که در تهیه بسیاری از مواد غذایی دیگر کاربرد دارد، طی فرایند طولانی و پر هزینه ای تولید می‌شود که با حذف مراحلی از این فرایند می‌توان از دور ریز مواد مغذی، با ارزش تغذیه‌ای بالا جلوگیری کرد.در این مطالعه، ترکیبات فنلی به عنوان یک أکثرمقدمه:شکر به عنوان یک ماده غذایی پر مصرف که در تهیه بسیاری از مواد غذایی دیگر کاربرد دارد، طی فرایند طولانی و پر هزینه ای تولید می‌شود که با حذف مراحلی از این فرایند می‌توان از دور ریز مواد مغذی، با ارزش تغذیه‌ای بالا جلوگیری کرد.در این مطالعه، ترکیبات فنلی به عنوان یک شاخص ارزشمند وماده غذایی عملگرا، مد نظر قرار گرفته است. مواد و روش‌ها: در این مطالعه اثر فاکتور زمان بر نمونه های شکر از طریق آزمون‌های تعیین میزان تغییرات ترکیبات فنلی با استفاده از روش Singleton، تغییرات شیمیایی (میزان قند،میزان اینورت،رنگ،میزان خاکستر، pH) و آزمون های میکروبی با استفاده از روش‌های استاندارد بین المللی ICUMSA اندازه گیری شده است. یافته‌ها:نتایج آزمون‌های میکروبی آلودگی باکتریایی مزوفیل را نشان می‌دهد. نتایج آزمون های شیمیایی نشان می‌دهد که با گذشت زمان در شکر بدون کلرساژ، شکر پخت ІІ و شکر پخت ІІІ میزان قند، اینورت و رنگ کاهش یافته و در میزان ترکیبات فنلی افزایش قابل توجهی مشاهده می شود. که در این رابطه بین نمونه ها تفاوت آماری معنی‌دار مشاهده می گردد. نتیجه‌گیری: با توجه به نتایج حاصله، با ایجاد شرایط کنترل شده، می‌توان شکر‌هایی را تولید کرد که علاوه بر جلوگیری از پدیده حذف مواد مغذی در زمان تولید منجر به حفظ و بعضاَ افزایش ارزش کیفی، در طی نگهداری شود تفاصيل المقالة -
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3 - The Effect of Different Concentrations of Activated Carbon with Bleaching Earth During Bleaching Process on Physicochemical Properties of Soybean Oil
N. Aliyar Zanjani Z. Piravi VanakConsidering the importance of bleaching earth with activated carbon in reduction of impurities in vegetable oils, this study was conducted to investigate the effects of bleaching process on physicochemical properties of the bleached soybean oil. The bleaching process wa أکثرConsidering the importance of bleaching earth with activated carbon in reduction of impurities in vegetable oils, this study was conducted to investigate the effects of bleaching process on physicochemical properties of the bleached soybean oil. The bleaching process was carried out with bleaching earth (1 % w/w) containing different concentrations of activated carbon (0.1 % up to 0.5 % w/w). The results indicated that bleaching process did not affect the structure of the oil while the percentage of free fatty acids (FFA) of the oil samples after bleaching was increased as compared to the blank. During bleaching, peroxide values of the samples and color were decreased. Since the vegetable oils have been shown to be the major sources in the diet therefore the refining particularly the bleaching process plays a decisive role in the production of high quality oil. Therefore this step is one of the critical control points (CCP) in ensuring the quality of the final product. تفاصيل المقالة -
حرية الوصول المقاله
4 - The Effect of Bleaching Process on the Physical and Chemical Characteristics of Canola and Sunflower Seed Oils
M. Haji Hoseini M. Ghavami A. Heidary-Nasab M. GharachorlooBleaching process is an essential stage in the refining of vegetable oils and fats. In this process the colour and the primary and secondary oxidation products are removed by the treatment with the acid activated bleaching earth .The aim of this project is to understand أکثرBleaching process is an essential stage in the refining of vegetable oils and fats. In this process the colour and the primary and secondary oxidation products are removed by the treatment with the acid activated bleaching earth .The aim of this project is to understand the effect of bleaching on the physical characteristics and chemical constituents of neutralized canola and sunflower seed oils. Canola and sunflower seed oils were bleached at 100o C for 30 minutes. The results indicated that there were significant reductions in peroxides and red and yellow colours of the oils. The induction period representing the oil resistance to oxidation was improved however the acidity was increased that might be due to the nature of the acid activated earth that has caused slight hydrolysis. Slight changes in fatty acid composition was observed that was due to the oxidation of poly unsaturated fatty acids namely linoleic acid in both oils. Some reduction in the total non saponifiable matter was observed. This might be due to the oxidation of tocopherols and changes of the sterols structures due to their conversion to steroidal hydrocarbons. تفاصيل المقالة -
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5 - Steady state behavior and maintenance planning of bleaching system in a paper plant
R Khanduja P.C Tewari D KumarThis paper presents the steady state behavior and maintenance planning of the bleaching system in a paper plant. The paper plant comprises of various systems including feeding, chipping, digesting, washing, bleaching, screening, stock preparation and paper making, etc. أکثرThis paper presents the steady state behavior and maintenance planning of the bleaching system in a paper plant. The paper plant comprises of various systems including feeding, chipping, digesting, washing, bleaching, screening, stock preparation and paper making, etc. One of the most important functionaries of a paper plant, on which quality of paper depends, is the bleaching system, where removal of coloring constituents is done to obtain the desired degree of brightness. The bleaching system consists of two subsystems A and B arranged in series with two states; good and failed. The mathematical modeling is carried out on the basis of Markov birth-death process using a probabilistic approach. An expression for steady state availability is also developed. Based upon the maintenance data available from medium sized paper plant, the effect of each working unit on the system availability behavior has been explained. In this regard, the behavioral chart for bleaching system has been given. Besides, a maintenance schedule has also been suggested and utilized for the purpose of maintenance planning of the bleaching system in a paper plant. The findings of this paper have been discussed with the concerned plant personnel and found to be highly beneficial for enhancing the performance level of the plant concerned. تفاصيل المقالة -
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6 - بررسی وضعیت سفیدشدگی مرجان ها در جزیره کیش ،خلیج فارس
آزاده صالح دوست محمد جواد جامی حسین نگارستان رضوان موسوی ندوشن بابا مخیرتشکیلات مرجانی، یکی ازبارورترین زیستگاه های دریایی از لحاظ تولیدانرژی ونرخ تولیدموادآلی محسوب می شوند. سفید شدگی همراه با مرگ مرجان یا عدم مرگ مرجان پاسخی به نوسان شرایط محیطی و استرس می باشد. این مطالعه در آبهای اطراف منطقه آزاد کیش در خلیج فارس صورت گرفت. روش مورد است أکثرتشکیلات مرجانی، یکی ازبارورترین زیستگاه های دریایی از لحاظ تولیدانرژی ونرخ تولیدموادآلی محسوب می شوند. سفید شدگی همراه با مرگ مرجان یا عدم مرگ مرجان پاسخی به نوسان شرایط محیطی و استرس می باشد. این مطالعه در آبهای اطراف منطقه آزاد کیش در خلیج فارس صورت گرفت. روش مورد استفاده در این مطالعه در بهارسال 1388 به جهت بررسی وضعیت مرجانهای زنده و مرده در اطراف جزیره کیش ، از روشTimed swims یاTSاستفاده شده است. مشاهده در 6 منطقه از آب های اطراف جزیره کیش شامل ناحیهPersian Gulf، Big coral، ژوراسیک پارک ، کلبه هور ، کشتی یونانی و شمال جزیره. صورت گرفت. در ناحیه ژوراسیک پارک45 درصد از مرجان ها مانندکلنی بزرگ جنس های Acropora sp و Porites sp بطور کامل سفید شده و از بین رفته بودند. کمترین میزان از نظر سفید شدگی در شمال جزیره و در حدود 10 درصد دیده شد. در ناحیهPersian Gulf نیزکلنی مرجان های مرده متعلق به جنس های Acropora sp. وsp.Porites مشاهده شد.جنسAcropora (مرجان شاخ گوزنی) کاملا" سفید شده و رسوب جلبکی روی این مرجان ها را پوشانده بود. فعالیت های انسانی مثل لنگر انداختن قایق های تفریحی و اسنور کلینگ در نواحی کم عمق ساحلی می توانند اثر مخرب بروی صخره های مرجانی داشته باشند. تفاصيل المقالة -
حرية الوصول المقاله
7 - Investigation of Soybean Oil Bleaching by Using Walnut Shell
Zeynab Forouzan Sepehr Maryam Gharachorloo Shima YousefiIn this research, the application of walnut shell ash, as an adsorbent for soybean oil bleaching, has been investigated. Therefore, neutralized soybean oil was bleached with 1 and 2% of walnut shell ash as well as commercial bleaching earth. Then, a series of chemical t أکثرIn this research, the application of walnut shell ash, as an adsorbent for soybean oil bleaching, has been investigated. Therefore, neutralized soybean oil was bleached with 1 and 2% of walnut shell ash as well as commercial bleaching earth. Then, a series of chemical tests such as amounts of carotenoids, chlorophylls, peroxide value, and free fatty acid content of bleached oils and oil retention of adsorbents were determined. The results indicated that bleaching with 2% walnut shell ash reduced carotenoids and chlorophyll contents up to 37.46 and 33.4%, respectively. Moreover, the red and yellow colors reduced in the oil bleached with 2% walnut shell ash and reached to 1.23 and 50 Lovibond, respectively. The oil retention by walnut shell ash (36.99%) was significantly lower than commercial bleaching earth (45.33%). Therefore, as a food waste, walnut shell ash can be used alone or in combination with acid activated earths or activated carbons for oil bleaching as a low cost adsorbent. تفاصيل المقالة -
حرية الوصول المقاله
8 - Degradation of some dyes using nanosized CeCuO3 photocatalyst: synthesis and characterization
Indu Bhati Anil Kumar Suresh C. AmetaCeCuO3 nanoparticles with diameter 4.36 nm was synthesized by a fast and simplemicrowave method using cerric sulphate tetra hydrate and copper sulphate pentahydrate asstarting reagents. CeCuO3 was synthesized under microwave heating for 6 min without calciningsteps. The أکثرCeCuO3 nanoparticles with diameter 4.36 nm was synthesized by a fast and simplemicrowave method using cerric sulphate tetra hydrate and copper sulphate pentahydrate asstarting reagents. CeCuO3 was synthesized under microwave heating for 6 min without calciningsteps. The synthesized products were characterized by X-ray powder diffraction (XRD) andscanning electron microscopy (SEM) and the photocatalytic behaviour of nanosized CeCuO3 wasalso studied spectrophotometrically through decolorization of yellowish orange and fast greendyes, a prompt water pollutant from textile industries. The effect of variation of differentparameters i.e. pH, amount of CeCuO3, concentration of dye and light intensity was observed onthe rate of photocatalytic bleaching. A Tentative mechanism for the photocatalytic bleaching ofdyes has been proposed. تفاصيل المقالة
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