مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    1-11
Measures: 
  • Citations: 

    0
  • Views: 

    901
  • Downloads: 

    0
Abstract: 

گاز طبیعی که قسمت عمده آن را متان تشکیل می دهد، سوخت خوبی برای وسیله های نقلیه است. چارچوب فلز آلی(MOFs) به عنوان یک گروه نو از مواد جاذب در ذخیره گاز طبیعی، توجه زیادی را به خود جلب کرده ­ اند. ساختارهای MOF با اتصال واحدهای ساختمانی ثانویه تشکیل شده از یون­ های فلزی و اتصال دهنده های آلی، شبکه­ های گوناگونی را تشکیل می دهند. این مواد منظم، دارای تخلخل بالا هستند و از قابلیت طراحی بالایی برخوردارند. این ویژگی، MOFها را برای کاربردهای ویژه در به دام اندازی و جذب مواد گوناگون مناسب کرده است. بررسی این مواد در جذب متان خالص متمرکز شده است، هر چند گاز طبیعی دارای مقدار کمی از هیدروکربن­ های بزرگ ­ تر مانند اتان و پروپان است که جذب بیش تری نسبت به متان دارا هستند. دراین مقاله، یک نمای کلی از وضعیت فعلی چارچوب فلز آلی برای ذخیره سازی متان نشان داده می شود.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 901

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    1-11
Measures: 
  • Citations: 

    0
  • Views: 

    653
  • Downloads: 

    0
Abstract: 

Natural gas, whose main component is methane, is an attractive fuel for vehicular applications. Metal-Organic Frameworks (MOFs) have received significant attention as a new class of adsorbents for natural gas storage. MOFs are typically constructed by connecting Secondary Building Units (SBUs) consist of metal ions with organic connectors to produce various networks. They are completely regular, have high porosity, and highly designable frameworks. These properties make MOFs suitable for various applications especially in trap and adsorption affinities for various compounds. Evaluation of these materials has focused on adsorption of pure methane, although commercial natural gas also contains small amounts of higher hydrocarbons such as ethane and propane, which adsorb more strongly than methane. In this view, we provide an overview of the current status of metal– organic frameworks for methane storage.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 653

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 1
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    13-20
Measures: 
  • Citations: 

    3
  • Views: 

    714
  • Downloads: 

    0
Abstract: 

در این پژوهش، کاتالیست V-SBA-16 با استفاده از ماده نانومتخلخل SBA-16 به عنوان بستر و کمپلکس وانادیم طی فرایند بازروانی تهیه شد. کاتالیست تهیه شده با استفاده از فناوری های جذب و واجذب نیتروژن، پراش پرتو ایکس، پرتو سنجی فرابنفش ـ مرئی و میکروسکوپ الکترونی عبوری مورد شناسایی قرار گرفت. نتیجه های آنالیزها نشان داد که ساختار منظم نانومتخلخل بستر در طی فرایند تهیه کاتالیست حفظ شده و دچار فروپاشی نشده است. کارایی کاتالیست در فرایند اکسایش مستقیم بنزن به فنل با استفاده از عامل اکسنده هیدروژن پراکسید در دماهای متفاوت واکنش (25، 60 و 90 درجه سلسیوس) مورد ارزیابی قرار گرفت. بالاترین راندمان فنل حدود %16 و با گزینش پذیری فنل %60 در دمای 60 درجه سلسیوس به دست آمد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 714

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 3 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 2
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    13-26
Measures: 
  • Citations: 

    0
  • Views: 

    584
  • Downloads: 

    0
Abstract: 

In this study, carbon nanotubes coated with iron oxide nanoparticles were synthesized by a co-deposited simultaneous method with initial salt ratios of 2 to 1 and 4 to 1. In order to study the structural, surface and magnetic properties, electron microscopy, magnetic residue, infrared Fourier transform, Raman, x-ray diffraction, nitrogen adsorption-desorption, and zero-point calculations were studied. The results obtained from the structural analysis indicate that iron oxide nanoparticles with 12. 2 nm and 13. 5 nm are in the range of 2 to 1 and 4 to 1 on carbon nanotubes, respectively. Also, for these proportions, the behavior of superparamagnetic with saturated magnetization was 11. 48 mg/g and 27. 97 emu/g, respectively. The results showed that, by choosing the right method and optimizing the effective parameters in the method of synthesis of magnetic carbon nanotubes, it is possible to directly change their surface properties and, as a result, nanostructures with specific surface properties in the “ Wide” range of laboratory conditions.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 584

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    21-30
Measures: 
  • Citations: 

    2
  • Views: 

    688
  • Downloads: 

    0
Abstract: 

واکنش احیای اکسیژن در سمت کاتد پیل های سوختنی غشا تبادل پروتون واکنشی کند است و بیش تر تلفات به این بخش از پیل مربوط می شود. به علت فرایندهای محدودکننده بسیاری که در این لایه واکنش رخ می دهد، مدل کردن این لایه اهمیت به سزایی دارد. مدل ارایه شده مدلی دوبعدی ـ دوفازی است که در آن کانال عبوری جریان، لایه نفوذ گازی، لایه ماکروحفره ها و لایه کاتالیست مدنظر قرار گرفته است. غلظت اجزای گازی، درصد اشباع آب مایع در طول کاتد و پتانسیل محلی یونومر در لایه کاتالیست با استفاده از حل معادله های مربوطه توسط نرم افزار متلب (Matlab) در تمام نقاط محاسبه شده است. پس از مقایسه نتیجه های به دست آمده از مدل و داده های آزمایشگاهی، تاثیر پارامترهای طراحی شامل میزان بارگذاری پلاتین، ضخامت لایه کاتالیست و کسر وزنی یونومر، برای رسیدن به بیش ترین جریان تولیدی بررسی شد. در ولتاژهای بالا مقدارهای بهینه برای میزان بارگذاری پلاتین، ضخامت لایه کاتالیست و کسر وزنی یونومر به ترتیب 0.9mg/cm2، 15mm و%55 در ولتاژهای پایین مقدارها به ترتیب 0.5mg/cm2، 30mm و %45 وزنی گزارش شد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 688

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 2 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Author(s): 

Rahmani Nlioofar | Bagheri Garmarudi Amir | Khanmohammadi Khorrami Mohammadreza

Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    27-36
Measures: 
  • Citations: 

    0
  • Views: 

    575
  • Downloads: 

    0
Abstract: 

In this study, nanosized ZSM-5 zeolite was synthesized for examining of optimum conditions of synthesis and the formation of zeolite ZSM-5 under different conditions based on two-level factorial experimental design, by hydrothermal method. Samples were synthesized without organic template and different conditions including the molar composition of the synthetic gel and reaction time were studied in a wide range. Then the samples for studying the formation of zeolite ZSM-5 were analyzed by X-ray diffraction and the results were compared with each other to obtain optimal conditions. Purpose of optimizing the assay was to achieve nanosized ZSM-5 zeolite with appropriate morphology and stability. Characterization of nanoparticles was performed by the Scanning electron microscope, Transmission electron microscope Fourier transform infrared spectroscopy and thermal gravimetric analysis. According to the two-level factorial experiment design, optimal conditions for the synthesis of nano-zeolite ZSM-5 include: Na2O/SiO2=0. 2، SiO2/Al2O3 =60، H2O/SiO2=53, Aging time=72h. Scanning electron microscopy showed that the smallest and the most optimal of particle size is approximately 44 nm and Fourier-transform infrared spectroscopy and Thermal gravimetric analysis confirmed the synthesis of nano-zeolite ZSM-5.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 575

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    31-39
Measures: 
  • Citations: 

    0
  • Views: 

    716
  • Downloads: 

    0
Abstract: 

در این مطالعه تجربی، اندازه گیری ضریب نفوذ مولکولی بنزوئیک اسید در نانوسیال ها پایه آبی دارای نانوذره های گاما آلومینا انجام شد. قطر نانوذره های مورد استفاده بین 10nm تا 20nm بود. دامنه نسبت های حجمی نانوذره ها به کار گرفته شده از 0.025% تا 0.8% بود. آزمایش ها در دمای ثابت 20oc انجام شد. نتیجه ها نشان دادند که نانوذره های گاما آلومینا بر نفوذ جرم در نانوسیال ها بی اثرند و هیچ گونه تغییر چشمگیری در ضریب نفوذ بنزوئیک اسید در نانوسیال های آب- گاما آلومینا نسبت به ضریب نفوذ آن در آب دیده نشد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 716

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 4
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    37-49
Measures: 
  • Citations: 

    0
  • Views: 

    606
  • Downloads: 

    0
Abstract: 

In this research, poly (ether)-block-poly (amide) copolymer was synthesized from polyphenylene oxide (PPO) and phenyl isocyanate (PIC) via coordination polymerization in the presence of TiCl4 and dried toluene. The effects of temperature, reaction time, TiCl4/PPO ratio, the concentration of monomer and toluene as a solvent on the yield of copolymerization were investigated. Chemical structure of block copolymer was confirmed by Hydrogen Nuclear Magnetic Resonance (1H NMR) spectroscopy. 1H NMR results were in good agreement with gel permeation chromatography (GPC). Molecular weight and molecular weight distribution of the copolymer are 5806 g/mol and 1. 25, respectively. Thermal properties of the copolymer were studied by Differential Scanning Calorimetry (DSC) measurement, in which the glass transition (Tg) of amide and ether blocks were 84˚ C and 164˚ C, respectively. The freeze-grinding method was used for the preparation of particles (grinding time = 2 hours). Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM) images exhibited micrometric and nano metric particles with regular and cubic structure. Obtained results from X-Ray Diffraction (XRD) showed that synthesized copolymer particles have a simple cubic crystal lattice of [100], [110], and [111].

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 606

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    41-46
Measures: 
  • Citations: 

    0
  • Views: 

    456
  • Downloads: 

    0
Abstract: 

جذب زیستی فلزهای سنگین، یک فرایند بسیار موثر در حذف این آلاینده ها از محلول های آبی است. ترکیب های دیواره سلولی جلبک ها دارای سلولز و همچنین مواد دیگری از جمله آلژینات و آگار است که نقش کلیدی در جذب زیستی کاتیون های فلزی بازی می کنند. جلبک ها به علت ارزان بودن از اهمیت ویژه ای برخوردارند. درحالی که سازوکارهایی که در جذب فلزها به وسیله باکتری ها دخالت دارند، بسیار پیچیده اند و وابستگی کامل به واکنش های فیزیکوشیمیایی یون فلزی در محلول، مکان های جذب سلولی و غیره دارند. میکروارگانیسم ها و جلبک ها به چرخه مواد غیرآلی در طبیعت کمک می کنند. در این پژوهش جذب زیستی نیکل به وسیله جلبک قرمزگراسیلاریا، جلبک های قهوه ای فوکوس و سیستوسیرا و باکتری گرم مثبت باسیلوس، مورد مطالعه قرار گرفت. پارامترهایی مانند غلظت فلز، pH، زمان، هم دما در این آزمایش مورد بررسی قرار گرفت. بیش ترین میزان جذب فلز به وسیله جلبک گراسیلاریا، سیستوسیرا و باسیلوس در pH حدود 6 و جلبک فوکوس در pH حدود 5 می باشد. بیشینه جذب در جاذب فوکوس حدود 0.9، گراسیلاریا 0.68، سیستوسیرا 0.34 و باسیلوس 0.65 میلی گرم بر لیتر است. مدت زمان تعادل در باکتری 120 دقیقه است در جلبک گراسیلاریا 400 دقیقه و در فوکوس 300 و سیستوسیرا حدود 350 دقیقه بوده است. داده های هم دما به وسیله مدل لانگمویر توصیف شد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 456

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 1
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    49-59
Measures: 
  • Citations: 

    0
  • Views: 

    591
  • Downloads: 

    0
Abstract: 

وجود ماده کربنی و کانی گوگردی از ویژگی های کانه مقاوم طلا است که باعث کاهش بازیابی طلا از این نوع کانه می شود. از دو نوع زغال (زغال معمولی و آنتراسیت) به عنوان جانشین ماده کربنی موجود در کانه مقاوم طلا به منظور بررسی قابلیت فانروکیت کرایسوسپوریوم برای کاهش توانایی ماده کربنی در جذب طلا استفاده شد. نتیجه ها نشان داد که ماده آنتراسیتی حدود 5 برابر بیشتر از زغال معمولی طلا جذب کرده است فانروکیت کرایسوسپوریوم توانایی آنتراسیت در جذب طلا را در دوره کشت 21 روزه و محیط کشت PDB (براث دکستروز سیب زمینی) تا حدود %85 و در محیط کشت MWB (ارزن و گندم) تا بیش از %95 کاهش داد. فانروکیت کرایسوسپوریوم هم چنین توانایی اکسید کردن گوگرد موجود در کانه مقاوم طلا را داراست. برای بررسی تاثیر قارچ روی مواد گوگردی موجود در کانه مقاوم، از پیریت به عنوان نماینده آن ها استفاده شد. در مجموع، کانی پیریت در دوره کشت 21 روزه، در pH برابر 7، %35 وزنی و در pH برابر 4، %30 وزنی، اکسید شد. پیش فرآوری قارچی دوباره برای کانه مقاوم طلای زرشوران با درصدهای گوناگون اورپیمت و طلا انجام گرفت. پس از دوره 14 روزه کشت، میزان استخراج طلا با فرایند سیانوراسیون برای نمونه های (1) (2210mm- حاوی اورپیمنت کمتر نسبت به نمونه کانه مقاوم طلای زرشوران)، (2) (همانند نمونه کانه مقاوم طلای زرشوران از نظر میزان اورپیمنت) و (3) (بخش +2210mm که تا بیش از %85 از اورپیمنت غنی است به ترتیب %30، %25و %1 افزایش یافت و کانی گوگردی موجود نیز در نمونه های (1) و (2) بیش از %50 اکسید شد. نتیجه های آزمایش ها نشان داد که فانروکیت کرایسوسپوریوم ریزموجودی موثر برای اکسید کردن کانی های گوگردی و خنثی کردن مواد کربنی موجود در کانه مقاوم طلا به شکل همزمان بوده و در مجموع پتانسیل بالایی برای افزایش بازیابی طلا در عملیات سیانوراسیون آن کانسنگ دارد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 591

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    51-58
Measures: 
  • Citations: 

    0
  • Views: 

    428
  • Downloads: 

    0
Abstract: 

In this study, aerobic photocatalytic oxidation of sulfides by TiO2@GO-CdSe and TiO2@GO-CdSeS nanocomposites under visible light irradiation were investigated. The nanocomposites were supported on the graphene oxide nano sheets via in situ syntheses of CdSe and TiO2 and then modified by CdSthrough a hydrothermal method. The nanocomposites were characterized by SEM imaging, XRD and EDAX analyses. The size of nanocomposites were distributed in a narrow range of 50-65 and 60-75 nm for TiO2@GO-CdSe and TiO2@GO-CdSeS, respectively. The yield of photocatalytic oxidation process was obtained 65% for TiO2@GO-CdSeS in optimized conditions. These nanocomposites show high activity under the mild condition and Visible light irradiation. The photocatalysts were recycled and reused 8 times without a significant decrease in activities.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 428

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    59-69
Measures: 
  • Citations: 

    0
  • Views: 

    532
  • Downloads: 

    0
Abstract: 

In presented research work, novel organophosphorus acids containing β-naphthol group was synthesized by one-pot three-component domino-Knoevenagel-Phospha-Michael reaction between β-naphthol, aromatic aldehydes and triethylphosphite under green and environmentally conditions. Multi-walled carbon nanotubes containing sulfamic acid functional group were used as a heterogeneous catalyst for decreasing reaction time, increasing yield and the completed of the reaction. The advantages of this synthesis are recyclability and reusability of nano-catalyst, simplicity, utility, suitable reaction time and good yields. Their structures of products were confirmed by Nuclear Magnetic Resonance spectroscopy of hydrogen, carbon, and phosphorus and the melting point of solid products was reported.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 532

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    61-71
Measures: 
  • Citations: 

    0
  • Views: 

    1317
  • Downloads: 

    0
Abstract: 

در این پژوهش، فلوتاسیون پیرولوزیت و کلسیت و امکان جدایش آن ها از یکدیگر با کلکتورهای کاتیونی و آنیونی مورد مطالعه قرار گرفت. نتیجه ها نشان داد که بیش ترین بازیابی فلوتاسیون پیرولوزیت با کلکتور آنیونی اولئیک اسید در PH=9 بیش ترین بازیابی در فلوتاسیون کاتیونی توسط دودسیل آمین در PH=8 به دست می آید. آنالیز FT-IR نشان داد که در این شرایط جذب اولئیک اسید و دودسیل آمین در سطح پیرولوزیت به ترتیب از نوع شیمیایی و فیزیکی است. با بررسی مواد شیمیایی گوناگون مشخص شد که در فلوتاسیون آنیونی، مس سولفات مناسب ترین ترکیب برای فعال سازی سطح پیرولوزیت و بازداشت کلسیت است. با استفاده از اولئیک اسید 10-4 مولار و مصرف 1000ppm مس سولفات بیش ترین مقدار بازیابی فلوتاسیون پیرولوزیت در PH=9 حدود 84 درصد به دست آمد. در این شرایط بازیابی کلسیت به حدود 38 درصد رسید. در فلوتاسیون کاتیونی، سدیم کربنات و کلسیم کلرید نقش موثری در بازداشت کلسیت بازی کردند. در حضور 10-4 مولار سدیم کربنات و در Ph=7.5 بازیابی کلسیت تا %13.7 کاهش می یافت، در حالی که در این شرایط بازیابی پیرولوزیت %90.5 بود. همچنین در Ph=7.5 با مصرف 5´10-4 مولار کلسیم کلرید بازیابی کلسیت به %10.8 کاهش یافته ولی بازیابی پیرولوزیت نیز اندکی کاهش یافته و به حدود 76.1 درصد رسید. بنابراین فلوتاسیون کاتیونی با استفاده از بازداشت کننده سدیم کربنات برای جدایش پیرولوزیت از کلسیت مناسب تر است.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1317

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 2
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    71-79
Measures: 
  • Citations: 

    0
  • Views: 

    682
  • Downloads: 

    0
Abstract: 

In this study, Fe3O4/ graphene nanocomposite was prepared by a gas/liquid interface reaction and characterized by XRD, IR and SEM techniques. Transmission electron microscope images revealed that the ultrafine Fe3O4 NPs are homogeneously deposited on the supporting G-O sheets and graphene oxide sheets could hinder the aggregation of Fe3O4 NPs. Then, the catalytic performance of the synthesized material on the thermal decomposition of ammonium perchlorate (AP) was investigated by ThermoGravimetry Analysis (TGA) and differential scanning calorimetry (DSC) techniques. The results of the thermal analysis showed that the composites exhibit better catalytic effect for the thermal decomposition of ammonium perchlorate than Fe3O4 NPs due to the combination of graphene sheets and Fe3O4 NPs.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 682

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    73-81
Measures: 
  • Citations: 

    0
  • Views: 

    1382
  • Downloads: 

    0
Abstract: 

باتوجه به اینکه گل حفاری در کیفیت چاه حفر شده و همچنین بازدهی عملیات حفاری تاثیر گذار است، بنابراین نقش به سزایی در عملیات حفاری بازی می کند. بنابراین در این پژوهش، تاثیر افزودنی های پلی اکریل آمید و نانوکامپوزیت باریت/ پلی آکریل آمید بر روی ویژگی های گل حفاری مورد ارزیابی قرار گرفت، که با تولید نانو کامپوزیت با پلیمریزاسیون محلول شد. سرانجام نانوکامپوزیت تولیدی به گل حفاری پایه آبی (350 میلی لیتر آب به همراه 10 گرم بنتونیت) افزوده شده و ویژگی های گل حفاری شامل گرانروی، میزان هرزروی سیال و ضخامت اندود گل مورد آزمایش قرار گرفت. به طور کلی، نتیجه ها نشان می دهد که افزودنی نانوکامپوزیت باعث کاهش ضخامت اندود گل و هرزروی سیال و همچنین موجب افزایش گرانروی گل حفاری می شود.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1382

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 2
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    81-95
Measures: 
  • Citations: 

    0
  • Views: 

    670
  • Downloads: 

    0
Abstract: 

Innovative nanofiller produced by poly(acrylic acid) attachment onto alumina nanoparticles was embedded into the polysulfone membrane. The efficiency of the nanofiltration membrane was investigated for hardness removal from water. Considering the feed concentration and pH as well as nanoparticle content, the optimization of process variables was performed using response surface methodology (RSM). The negative charge of the membrane surface caused by carboxyl functional groups on alumina nanoparticles elevated the cation removal efficiency from water. Statistical analysis revealed that 0. 5 wt. % nanoparticles in the membrane matrix along with a high concentration of Mg2+ ions in water at pH 6. 84 were the optimum condition to achieve the highest water softening efficiency. The predicted model well matched with experimental results suggesting a practical preparation and process conditions for achieving a water-softener membrane. Furthermore, the membrane permeability of prepared nanocomposite membranes was improved to higher amounts due to the induced changes in membrane bulk structure and surface hydrophilicity.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 670

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    83-89
Measures: 
  • Citations: 

    0
  • Views: 

    506
  • Downloads: 

    0
Abstract: 

افزایش طول منطقه مایع متراکم در مبدل های ترموسیفونی و کاهش ضریب انتقال حرارت به همراه تغییر دما در لوله ها و در نهایت تشکیل رسوب از اصلی ترین مشکلات مبدل های ترموسیفونی است. یکی از روش های موفق درحل این مشکل ها، استفاده از نانو سیال های مناسب است. در این مقاله به بررسی اثر استفاده از نانو سیال در این نوع سامانه های گرمایی پرداخته شده است و با استفاده از شبیه سازی یک مبدل ترموسیفونی با هندسه مشخص، تاثیر استفاده از نانو سیال بر عملکرد گرمایی و طول منطقه مایع متراکم موردمطالعه قرارگرفته است. نتیجه این مطالعه به خوبی نشان می دهد که چگونه ضریب انتقال گرما با افزایش غلظت نانو سیال افزایش یافته و سرانجام، افزون بر کاهش سطح انتقال گرمای لازم و کوچک تر شدن اندازه مبدل، طول منطقه مایع متراکم نیز کاهش داده می شود.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 506

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    1394
  • Volume: 

    34
  • Issue: 

    3
  • Pages: 

    91-102
Measures: 
  • Citations: 

    0
  • Views: 

    1563
  • Downloads: 

    0
Abstract: 

استفاده از آب شیرین کن ها یکی از راه حل های مقابله با بحران آب در کشور می باشد. روش رطوبت زنی- رطوبت زدایی هوا یا به اختصار HD، یکی از روش های نمک زدایی از آبهای شور در ظرفیت های پایین است که طی سالهای اخیر مورد توجه قرار گرفته است. در این مقاله طرحی برای ترکیب آب شیرین کن HD خورشیدی با آب گرم کن خورشیدی خانگی ارایه شده است. این دستگاه در مقیاس خانگی و برای تامین همزمان آب شرب و آب گرم مصرفی یک خانوار طراحی شده و برای مناطق دورافتاده و کم جمعیت کویری گزینه ای مناسب می باشد. پس از بررسی ترکیب های گوناگون این دو دستگاه و انتخاب و ارزیابی فرایند نهایی، ساخت دستگاه ترکیبی در پژوهشکده توسعه صنایع شیمیایی ایران انجام شد و آزمایش های لازم بر روی آن صورت گرفت. پارامترهای گوناگون و موثر در عملکرد دستگاه مانند شدت جریان ورودی به کندانسور، محدوده دمایی عملکرد آب شیرین کن و میزان تابش دریافتی خورشید مورد بررسی قرار گرفت. این دستگاه با توجه به شرایط تابش خورشید در کرج در ماه های بهار و تابستان مورد ارزیابی قرار گرفت که بر این اساس با استفاده از 4 عدد کلکتور خورشیدی می تواند روزانه تا 20 لیتر آب شیرین و حدود 250 لیتر آب گرم تولید کند. با توجه به اینکه در فرایند طراحی شده آب شور خروجی از آب شیرین کن به عنوان آب گرم مصرفی مورد استفاده قرار می گیرد، درنتیجه میزان استفاده از آب گرم توسط مصرف کننده دورریز آب دستگاه کاهش می یابد که بر اساس طراحی صورت گرفته می تواند در برخی روزها به صفر برسد. بنابراین افزون بر به کارگیری انرژی خورشید در تامین گرمای مورد نیاز، صرفه جویی مناسبی در مصرف آب صورت می گیرد.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1563

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Author(s): 

Ghazanfarpour Darjani Magid | Babapour Kooshalshahi Mahboobeh | Mohamad Alikhani Leila

Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    97-108
Measures: 
  • Citations: 

    0
  • Views: 

    677
  • Downloads: 

    0
Abstract: 

Unsymmetrical piperazines are key constituents of many anti-psychotic pharmaceuticals and bioactive compounds. Given that the selective introduction of an aryl and alkyl motif onto the piperazine skeleton is not always straightforward, direct arylation or alkylation of 1, 4-diaza-bicyclo[2. 2. 2]octane would obviate the inefficiencies associated with the preparation of these target valuable molecules. We have utilized alkyl chlorides as the alkyl source, aryl triflates as the active aryl source, and 1, 4-diaza-bicyclo[2. 2. 2]octane for the synthesis of N-alkyl-N′-arylpiperazines. The optimum conditions are developed using CuCl and t-BuOLi in PEG-400. Substrates bearing electron-deficient as well as electron-rich groups were successfully coupled under the optimum reaction conditions.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 677

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    109-118
Measures: 
  • Citations: 

    0
  • Views: 

    480
  • Downloads: 

    0
Abstract: 

Today, air pollution is one of the important environmental problems in most developing countries. In this paper, using density functional theory calculations, the mechanism of NO reduction is investigated over B12N12 and B11N12C nanocages. The proposed pathway for this reaction is as 2NO → N2O + Oads and Oads + N2O → N2 + O2. The results indicate that C-doping increases the surface reactivity of B12N12 nanocage. The activation energies and calculated thermodynamic parameters show that the B11N12C nanocage has a better catalytic activity than B12N12, which could be due to the presence of doped carbon atom in this structure.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 480

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    119-124
Measures: 
  • Citations: 

    0
  • Views: 

    1395
  • Downloads: 

    0
Abstract: 

Due to the high solubility rate of urea in water, a noticeable portion of this fertilizer migrates into the underneath layers of soil and will be out of access of plants. This leakage not only is non-economic but also is dangerous for the environment. To avoid this leakage, different methods have been used which one of more applicable methods is the coating of the urea for controlling its solubility rate in the water. In this paper, xanthan gum and alginate powder were used as coating materials for urea pellets and the effects of these coatings on the releasing rate of urea was investigated. Single and double layer coatings were produced in a gas-solid-liquid fluidize bed. The best result has been obtained from the two-layer coating of xanthan gum and alginate. The results showed that this coating increases the urea release time up to 12 days.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1395

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    127-139
Measures: 
  • Citations: 

    0
  • Views: 

    597
  • Downloads: 

    0
Abstract: 

This study investigates the effect of different concentrations of clay on the structure and performance of polysulfone (PSf) UltraFiltration (UF) membranes for landfill leachate treatment. The membranes were prepared by phase inversion method via dissolving PSf powder in N-methyl-2-pyrrolidone (NMP) solvent at the presence of different content of clay. Performance and fouling behavior of prepared membranes were evaluated using a lab-scale cross-flow setup. The structure and morphology of the modified membranes were investigated by Field Emission ScanningElectron Microscopy(FESEM), Atomic Force Microscopy (AFM) and Energy Dispersive X-ray (EDX). The results confirmed that the adsorbent-modified UF membranes had higher flux and improved COD removal in comparison to the neat membrane. COD removal and NOM removal for 1. 5% clay membrane was 35% and 51% respectively, and It was higher than the neat membrane (24% COD removal and 34% NOM removal). As the neat membrane was capable of reducing the COD by only 24%, It can be concluded that the addition of the adsorbents significantly enhanced the overall performance of the ultrafiltration membrane.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 597

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    141-156
Measures: 
  • Citations: 

    0
  • Views: 

    1145
  • Downloads: 

    0
Abstract: 

Nowadays, due to the environmental challenges of industrial wastewater containing toxic and dangerous substances, there is particular importance in needing new and effective technologies for wastewater treatment. Electrochemical methods as one of the advanced oxidation processes used effectively for the decomposition of organic compounds. The Electro-Fenton process is one of these processes that it generates hydroxyl radicals. During electrochemical reactions and by applying electricity to the anode and cathode electrodes, hydroxyl radicals attack the pollutants and remove them. The purpose of this study is to evaluate the performance of the electro-Fenton process as an industrial wastewater pretreatment with a high concentration of olefin materials. In this study, an electro-Fenton batch reactor equipped with two iron electrodes and DCpower supply was used in the lab scale for the removing resistant and organic compounds. Effects of four operational parameters such as pH, concentration of H2O2 (hydrogen peroxide), reaction time and concentration of divalent iron were evaluated at the 5 levels and finally the optimum conditions of any factor was obtained by using of Taguchi statistics method in from of H2O2 160 mM (Level 4), pH factor 3 (Level 1), concentration of iron 40 mg l-1 (Level 5) and time of 15 min (Level 1), respectively. Also, the first and second order synthetic models were fitted to the experimental data. Results indicated that the second order of synthetic models has the best agreement with the experimental values.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 1145

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Author(s): 

Seyyed Alizadeh Ganji Seyyed Mohammad | HAYATI MOHAMMAD

Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    157-172
Measures: 
  • Citations: 

    0
  • Views: 

    531
  • Downloads: 

    0
Abstract: 

Rare elements in nature are often found in the form of oxide, and since they are very similar in physical and chemical properties, their separation is very difficult. Hence, the study and selection of the most appropriate methods for the separation of rare elements are very important and necessary. Therefore, in this first step, in order to model and optimize the effective factors on improving the separation of Dispersum and Gadolinium, five factors including pH, Cyanex 272 to Depa ratio, solvent extraction’ s concentration, time and lactic acid’ s concentration were selected. Then, DX7 software was used to design the experiments and based on that, 29 tests were determined. But on the other hand, in carrying out experiments, such things as weighing with the device, preparing solutions with a specific concentration, removing different volumes, and etching of the items that can cause the error and therefore the uncertainty is why the discussion of probabilistic analysis in order to Modeling under conditions of uncertainty can be very useful for the assurance of the results. For this purpose, in the second step, based on the data obtained from the experiments and the relationships obtained between the input and output variables, first, the type and characteristics of the probability distribution function, each of the five effective input parameters were determined and based on them and with Considering the simulation results, the characteristics of the distribution parameters of the output parameters (percent recovery of dysprosium and gadolinium) were obtained.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 531

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    173-182
Measures: 
  • Citations: 

    0
  • Views: 

    686
  • Downloads: 

    0
Abstract: 

Precise volume fraction percentage prediction in water-gasoil-air three-phase flows in unstable operational conditions is an important parameter in the oil and petroleum industry. In this research, the volume fraction percentage was measured precisely in water-gasoil-air three-phase flows by using single energy gamma ray attenuation technique and neural network, for the first time. The volume fraction percentage determination in three-phase flows requires least two gamma radioactive sources with different energies while in this study, we used just a 137Cs source (with the single energy of 662 keV) and a NaI detector. Also, the multilayer perceptron (MLP) neural network was implemented to predict the volume fraction percentage. The acquired results from an experimental setup provides the required data for training and testing the network. The inputs of ANN have registered spectra in the transmitted detector as the dataset matrix for ANN consisted of a (Y118×42). In this ANN, the number of neurons in the input, hidden and output layers are 118, 10 and 3, respectively. Using this proposed method, the volume fraction was predicted in water-gasoil-air three-phase flows with Mean Relative Error percentage (MRE%) less than 6. 95%. Also, the Root Mean Square Error (RMSE) was calculated simultaneous 2. 60. The set-up used is simpler than other proposed methods and cost, radiation safety and shielding requirements are minimized.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 686

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    183-193
Measures: 
  • Citations: 

    0
  • Views: 

    607
  • Downloads: 

    0
Abstract: 

Cement kiln is as the heart of the cement plant in clinker production that gas and solid materials are in contact with each other in countercurrent flow. In this study, a mathematical model of concentrations distribution and clinker phases according to the mass equations and kinetics of chemical reactions in the furnace length were studied. In steady state investigated Modeling whit coating effect and maintaining the property of physical and chemical. The role of effective parameters such as Composition of feed, temperature, activation energy, material flow rate, cross section and rotational speed of kiln investigated on the governing equations and models and these equations solved in steady-state using software Matlab-7. The results of the model were compared with the experimental data that good agreement are between predicted by the model and experimental data and an error of less than 3% for the data obtained from the model and experimental is the acceptable answer for model validation.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 607

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    195-205
Measures: 
  • Citations: 

    0
  • Views: 

    457
  • Downloads: 

    0
Abstract: 

In present work, poly(vinyl alcohol)-g-acrylamide was synthesized with two initiator systems, which contain ceric ammonium nitrate and ammonium persulfate/sodium metabisulfite redox systems. The structure of the graft copolymers was confirmed by Fourier Transform InfraRed (FT-IR) spectroscopy and ThermoGravimetric Analysis (TGA). The inhibition effects of produced graft copolymers (as new kinetic hydrate inhibitors) and polyvinyl alcohol were investigated on gas hydrate formation with a methane-propane mixture which forms the structure II of the hydrate. In all experiments, the initial pressure was adjusted at 23 bar, temperature at 2 ˚ C, and the stirring rate at 400 rpm. All of the tested materials reduce hydrate formation rate and their inhibition strength was PVA-g-AAM1

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 457

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    207-221
Measures: 
  • Citations: 

    0
  • Views: 

    473
  • Downloads: 

    0
Abstract: 

Carbonate acidizing modeling presents an effective tool to determine dynamic behavior trends during matrix acidizing treatment. A successful matrix acidizing process requires a minimum volume of injected acid while creating highly conductive wormholes. In this work, the two-scale continuum model was used to simulate carbonate acidizing using finite difference approach. This model describes the reactive transport of acid at the Darcy scale and determines the local permeability, porosity, pore radius, and solid-fluid interfacial area changes at the pore-scale through structure-property relationships. In this study, a two-dimensional model was employed with constant flow rate inlet boundary condition, constant pressure outlet boundary condition, and no flow boundary condition on the lateral sides. To perform a grid independent verification, the normalized acid concentration was plotted versus mesh elements which, then, results in determining the optimum number of grid blocks. To solve governing equations, finite difference approach was used by employing initial and boundary conditions. The results of the two-dimensional homogeneous model revealed that there is a uniform acid concentration profile with a reduction trend during the model length. A sensitivity study on acid injection velocity in a heterogeneous model showed that there is an optimum injection velocity of 0. 33 to 1. 5 cm/s in which deep wormholes with a minimal amount of acid are created. Moreover, as time passes, the reactive dissolution process takes place and results in a dynamic change in the model porosity. This model indicated a good capability to qualitatively capture the experimentally observed wormhole propagation and growth.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 473

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    223-236
Measures: 
  • Citations: 

    0
  • Views: 

    526
  • Downloads: 

    0
Abstract: 

As polymer gels were successful in water shutoff production, in this research a polymer gel of sulfonated polyacrylamide copolymer and chromium triacetate as crosslinker was studied. For this purpose, bottle tests and filter gel system were used for the first time in the country and also strain sweep tests were carried out. According to the results, quadratic equations based on the parameters were presented predicting the rupture pressure gradient due to the oil and water injection and output gel because of oil and water injection based on polymer and chromium triacetate concentrations. The results showed that polymer concentration among crosslinker concentration and their interaction had the most effect on rupture pressure gradient and output gel due to oil and water injection. Besides, in the constant concentration of crosslinker, the increase of copolymer concentration caused an increase of rupture pressure to 5 times due to the increase of elastic modulus of the gel network and its strength. So by increasing of strain up to 1000%, the gel strength was stable. In fact, up to strain less than 100%, the hydrogel can keep and return to its initial shape. The results of gel rupture led to present a new mechanism to show the disproportionate permeability reduction (called as the creation of greater ruptures inside of gel by oil instead of water) which in that at same condition of experiments the ability of oil in gel rupture and creating greater rupture is more than water.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 526

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    237-250
Measures: 
  • Citations: 

    0
  • Views: 

    532
  • Downloads: 

    0
Abstract: 

In this study, the polyamide6/ thermoplastic starch (TPS) blends were prepared. Firstly, the starch became thermoplastic and was chemically modified using glycerol and maleic anhydride, under different conditions. After the preparation of maleated thermoplastic starch (MTPS), polyamide6/ MTPS (or TPS) blends were produced considering three variables; and the effects of various variables were investigated on their bio-degradability. In both steps, the experimental design method of Response Surface Methodology (RSM) was used. In the first step, the effects of Maleic Anhydride (MA) amount, time and temperature of the reaction were evaluated on the “ degree of MAgrafted on the starch” . With increasing MA content, the processing time and temperature, higher MA grafting was achieved. While at a higher temperature and longer time, it was constant or slightly decreased. The highest grafting of MA was obtained at 140 º C, 10 min and 4-6 % MA. In the second step, the influences of polyamide6/starch ratio, degree of MA grafting and degradation time were studied on the bio-degradability of the blends in the active sludge, in 90 days. Samples having TPS, showed some weight losses (or degradation) comparing to the purepolyamide6 which had no degradation. The amount of bio-degradation increased clearly with increasing MA grafted on the starch and MTPS amount. A blend containing 30 % MTPS, reached 45 % weight loss after 75 days. Using RSM, the equations of “ degree of MA grafting” and “ bio-degradation” versus variables, were obtained with suitable accuracy and low error. Besides, the interactions between the parameters were discussed considering 3D plots and the coefficients of the equations. The predicted results from the equations had a good fitting with the experimental data.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 532

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
Issue Info: 
  • Year: 

    2018
  • Volume: 

    37
  • Issue: 

    3
  • Pages: 

    251-260
Measures: 
  • Citations: 

    0
  • Views: 

    683
  • Downloads: 

    0
Abstract: 

Environment pollution and emission of toxic gases are one of the most important human challenges in the current century. Among polluted gases, land-fill gas with a high percent of methane could be considered as a plentiful source of energy. Biofiltration is a simple and economical method for removal of some contaminants such as hydrogen sulfide which is strongly toxic and corrosive. In this method, sweetening is done by passing the polluted gas through the bed of microorganism. For this purpose, a biofilter column of plexi glass with 15cm internal diameter and 2 m height was designed and constructed. The bed of this column was vermicompost mixed with the seashell. Then Thiobacillus thioparus bacteria which is cultured in the lab was previously, stabilized on the surface of the filling. The ability of this biofilter in 30 ppm concentration of H2S and different flow rate of landfill gas, in ambient temperature and atmospheric pressure, was studied. According to the experiments, it is observed that during 2 minutes, the yield is higher than 80%. In this condition, the concentration of H2S is desirable. Of course, in the study, the efficiency of biofilter in 30 ppm of H2S and flow rate of 2 L/min of polluted gas, was about 90 percent.

Yearly Impact: مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic Resources

View 683

مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesDownload 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesCitation 0 مرکز اطلاعات علمی Scientific Information Database (SID) - Trusted Source for Research and Academic ResourcesRefrence 0
telegram sharing button
whatsapp sharing button
linkedin sharing button
twitter sharing button
email sharing button
email sharing button
email sharing button
sharethis sharing button