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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Nanochemistry Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Acetaminophen,Tryptophan,Electrocatalysis,Carbon Nanotube,Modified carbon paste electrode,levodopa
- چکیده:
- چکیده انگلیسی: In the present paper, the use of a novel carbon paste electrode modified by 7,8-dihydroxy-3,3,6-trimethyl-3,4-dihydrodibenzo[b,d]furan-1(2H)-one (DTD) and oxidized multi-walled carbon nanotubes (OCNTs) is described for determination of levodopa (LD), acetaminophen (AC) and tryptophan (Trp) by a simple and rapid method. At first, the electrochemical behavior of DTD is studied, then, the mediated oxidation of LD at the modified electrode is investigated. At the optimum pH of 7.4, the oxidation of LD occurs at a potential about 330 mV less positive than that of an unmodified carbon paste electrode. Based on differential pulse voltammetry (DPV), the oxidation current of LD exhibits a linear range between 1.0 and 2000.0 μM of LD with a detection limit (3σ) of 0.36 μM. DPV was also used for simultaneous determination of LD, AC and Trp at the modified electrode. Finally, the proposed electrochemical sensor was used for determinations of these substances in human serum sample.
- انتشار مقاله: 15-02-1394
- نویسندگان: Mohammad Mazloum-Ardakani,Abolfazl Naser-Sadrabadi,Alireza Khoshroo
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanostructures
- نوع مقاله: Journal Article
- کلمات کلیدی: Nickel nanoparticles,Electrospinning,Ethanol electrooxidation,Core–shell titanium dioxide /carbon nanofibers
- چکیده:
- چکیده انگلیسی: Abstract
Recently alcohol fuel cells has been increased consideration because of their environmental friendliness, high energy conversion efficiency and low emissions. Many effort have been made to improve the electro-oxidation performance of alcohols such as methanol, ethanol and propanol. In this work, a new method for ethanol oxidation based on core–shell titanium dioxide / carbon nanofibers (TiO2@C NFs), TiO2 as a core and carbon as a shell, decorated Ni nanoparticles (NiNPs) is presented. TiO2@C NFs were prepared by mixing the electrospinning technique and hydrothermal method. Nickel nanoparticles were electrodeposed on the surface of TiO2@C NFs denoted as TiO2@C- Ni. The catalyst was characterized by SEM and electrochemical methods. Performance of ethanol oxidation was investigated in aqueous NaOH solutions by chronoamperometry and cyclic voltammetry. The electrochemical measurements showed that this electrode is effective and has good electrocatalytic activity for ethanol oxidation and the structures of nanofibers have important effect on the electrooxidation of ethanol. The synergy between Ni, carbon shell and TiO2 support, boost ethanol oxidation on TiO2@C- Ni.
Keywords: Ethanol electrooxidation; Electrospinning; Nickel nanoparticles; Core–shell titanium dioxide /carbon nanofibers- انتشار مقاله: 25-07-1396
- نویسندگان: Mozhgan Yavari,Mohammad Mazloum-Ardakani,Alireza Khoshroo
- مشاهده
- جایگاه : پژوهشی
- مجله: Biquarterly Iranian Journal of Analytical Chemistry
- نوع مقاله: Journal Article
- کلمات کلیدی: Response surface methodology,Ionophore,Central composite design,Ion-Selective Electrode,Polyvinyl Chloride Membrane
- چکیده: در این کار روش سطح پاسخ همراه با روش طرح ترکیب مرکزی برای شبیهسازی و بهینهسازی اثر برخی متغیرها (مقادیر پلیوینیلکلرید، یونوفر، افزودنی و نرمکننده) بر عملکرد الکترود یونگزین سرب استفاده شده است. شیب 1/29 میلیولت در مقادیر بهینه از پلیوینیلکلرید (0283/0 گرم)، یونوفر(0074/0 گرم)، افزودنی (002/0 گرم) و نرم کننده (060/0 گرم) به دست آمد. محدوده خطی غلظت 1-10×0/1-5-10×0/1 مولار با روش پتانسیومتری برای سرب بدست آمد. تکنیک اسپکتروسکوپی امپدانس الکتروشیمیایی برای ارزیابی مکانیسم پاسخ الکترود بکار برده شد. نتایج بدست آمده از اسپکتروسکوپی امپدانس الکتروشیمیایی محدوده خطی غلظتی از 6-10× 0/1 تا 1-10×0/1 مولار را نشان میدهد. همچنین در مقایسه با روش پتانسیومتری محدوده pH بدست آمده از 3 تا 5/5 به مقدار 5/2 تا 0/6 افزایش پیدا کرد.
- چکیده انگلیسی: In this work, response surface methodology in conjunction with central composite design for modeling and optimization of the influence of some process variables (polyvinyl chloride (F1), ionophore (F2), additive (F3) and plasticizer (F4) amounts), on the performance of polyvinyl chloride membrane lead (ІІ) ion-selective electrode is discussed. The slope of 29.1 ± 0.1 mV at the optimal amounts of polyvinyl chloride (0.0283 g), ionophore (0.0074 g), additive (0.002 g) and plasticizer (0.060 g) has been achieved. The electrode exhibited a linear potential response to lead (II) in the concentration range of 1.0 × 10-5 mol L-1 to 1.0 × 10-1 mol L-1 over pH range of 3.0 - 5.5. Greatly, the alternating current impedance technique was applied to investigate the response mechanism of the electrode. The results were obtained from electrochemical impedance spectroscopy shows a linear concentrations range of 1.0 × 10-6 mol L-1 to 1.0×10-1 mol L-1 and in comparison with potentiometry, the pH range increased to 2.5 − 6.0.
- انتشار مقاله: 19-07-1395
- نویسندگان: Mohammad Mazloum-Ardakani,Azimeh Mandegari,Alireza Khoshroo Khoshroo,Saeed Masoum,Hadi Kargar
- مشاهده
- جایگاه : پژوهشی
- مجله: Advances in Mathematical Finance and Application
- نوع مقاله: Journal Article
- کلمات کلیدی: DEA,cost saving,Benchmarking,Finance
- چکیده:
- چکیده انگلیسی: Efficient use of assets in agriculture is a goal for policy-makers and farmers. Agricultural input resources are scarce therefore optimum use of inputs in different agricultural operations is important. Mathematical programming technique such as data envelopment analysis (DEA) is a well-known approach for estimation efficiency of agricultural DMUs. In this study, efficiency of kidney bean production in twelve provinces of Iran has been studied. Inputs were cost of tillage, planting, cultivation, harvesting and land. Output included total production value of kidney bean. Land cost is a non-controllable variable. Therefore; a non-discretionary DEA approach was applied to estimate efficiency of kidney bean production. The average value of technical efficiency score of kidney bean production was 0.74. Results showed that 58 percent of DMUs were efficient and the rest were inefficient. In optimum condition based on the proposed model, tillage, planting, cultivation and harvesting costs is decreased by 34.48%, 11.92%, 27.87% and 7.27%, respectively, without decreasing kidney bean production level.
- انتشار مقاله: 20-05-1399
- نویسندگان: Alireza Khoshroo,Sanjeet Singh
- مشاهده