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Search Results: 1 - 10 of 151588 matches for " Mohammad K. Amini "
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Effect of Elemental Composition on the Structure, Electrochemical Properties, and Ozone Production Activity of Ti/Sn -Sb-Ni Electrodes Prepared by Thermal Pyrolysis Method
Hamed Shekarchizade,Mohammad K. Amini
International Journal of Electrochemistry , 2011, DOI: 10.4061/2011/240837
Abstract: Ti/SnO2-Sb-Ni electrodes with various Ni- and Sb-doping levels have been prepared by dip-coating thermal pyrolysis procedure, and their simultaneous electrochemical ozone production (EOP) and oxygen evolution reaction (OER) were investigated. The effects of electrode composition on the nanostructure, morphology, electrochemical behavior, kinetic parameters, and lifetime of the electrodes were systematically studied using X-ray diffraction, scanning electron microscopy, cyclic voltammetry, linear sweep voltammetry, and chronopotentiometry. Dissolved ozone was produced in a quartz cell and its concentration was monitored by in situ UV spectrophotometry. The presence of small amounts of Ni (Ni?:?Sn atomic ratio of 0.2?:?100) gives valuable characteristics to the electrodes such as increasing EOP activity and service life. Higher Ni concentrations increase the electrode film resistance and decrease its capacitance, roughness factor, and service life, while increasing Sb level up to 12 atom% improves the electrode performance with respect to these parameters. Nevertheless, the Sb/Sn atomic ratio of more than 2% reduces the EOP current efficiency in favor of OER. The optimum composition of the electrode for EOP was determined to be Sb/Sn and Ni/Sn atomic ratios of 2% and 0.2%, respectively. The highest current efficiency was 48.3% in 0.1?M H2SO4 solution at room temperature. 1. Introduction Ozone (O3), as an environmentally friendly reagent with high oxidizing power, has found a broad range of applications in various fields such as water and wastewater treatment, sterilization of surgical equipments, bleaching processes, cleaning of semiconductor materials, and chemical synthesis [1–5]. There are two main methods for preparation of dissolved ozone: corona discharge followed by dissolving ozone into solution and electrolysis [6]. The latter method has the advantages of being a simple process which produces relatively high concentrations of ozone directly into solution without producing harmful nitrogen oxides and without need for a high voltage power source as compared to corona discharge. The OER (1) is thermodynamically more favorable and severely competes with EOP (2) on the anode of an electrochemical ozone generator. Consequently, minimizing OER is a key requirement for EOP with a reasonable current efficiency. This can be achieved by suitable choice of the anode material to have a high overpotential for OER. In addition, the anode should have good conductance, high durability under drastic operating conditions, and particularly good electrocatalytic
A Simple and Selective Flow-Injection Potentiometric Method for Determination of Iodide Based on a Coated Glassy Carbon Electrode Sensor
Saeed S. Beheshti, Mohammad K. Amini
International Journal of Electrochemical Science , 2007,
Abstract: A flow-injection (FI) method is reported for the determination of iodide based on potentiometric detection, using a membrane electrode containing bis(4-chlorothiophenolato)mercury(II) [Hg(CTP)2] as the active component. The response of the system was evaluated with regard to the parameters of the membrane electrode and the FI system. The calibration curve for iodide at the optimized conditions including 0.01 M sodium sulfate (pH 6.0) carrier solution with a flow rate of 1 mL min-1 and an injection volume of 100 mL was linear over the range 1.0×10-6-7.6×10-2 M with a Nernstian slope of -59.4 mV per decade of iodide activity. The influence of several common inorganic and organic anions on the response of the FI system was investigated and selectivity coefficients were evaluated. The sensor shows high selectivity towards iodide, which can be related to the selective interaction of iodide as a soft anion with mercury atom in Hg(CTP)2 as a soft metal center. This is certified by the very low tendency of the sensor towards chloride, bromide, and the highly lipophilic anions such as perchlorate, salicylate, nitrate, nitrite, and thiocyanate. The system exhibited a fast response time of less than 5 s (in the batch mode), a detection limit of 5.0×10-7 M and a relative standard deviation of 0.6% at 0.1 mM iodide. The sampling frequency was between 40-120 h-1 depending on the concentration of iodide in the measuring solution. The proposed system was applied to the determination of iodide in a pharmaceutical preparation and the results were compared with a standard potentiometric method based on silver indicator electrode.
Square-Wave Voltammetric Determination of Ascorbic Acid Based on its Electrocatalytic Oxidation at Zeolite-Modified Carbon-Paste Electrodes
Alireza Nezamzadeh, Mohammad K. Amini, Hossein Faghihian
International Journal of Electrochemical Science , 2007,
Abstract: Carbon-paste electrodes modified with Fe(III)-Y zeolite have been used to study the electrocatalytic oxidation of ascorbic acid. The ion-exchange behavior of the modified electrodes in different supporting electrolytes was investigated. Maximum cathodic current due to reduction of the exchanged Fe(III) ions was observed in phosphate buffer, pH 5. The modified electrode acts as a catalyst for electrooxidation of ascorbic acid, lowering the overpotential of the reaction by ~200 mV. The faster rate of electron transfer results in a great enhancement of the cathodic peak current compared to those observed for the unmodified electrode. The effect of several parameters such as pH and concentration of the supporting electrolyte was investigated. The square-wave voltammetric response of the electrode to ascorbic acid is linear in the range 4.0×10-7 to 1.2×10-3 M with a detection limit of 2×10-8 M. The interfering effect of several cationic species and organic compounds was investigated and tolerance limits were obtained. The method was applied to the determination of ascorbic acid in citrus fruits.
Iodide Selective Electrodes Based on Bis(2-mercaptobenzothiazolato) Mercury(II) and Bis(4-chlorothiophenolato) Mercury(II) Carriers
Mohammad K. Amini,Mehrorang Ghaedi,Ali Rafi,Mohammad. H. Habibi,Morteza M. Zohory
Sensors , 2003, DOI: 10.3390/s31100509
Abstract: New iodide-selective electrodes based on bis(2-mercaptobenzothiazolato) mercury(II) [Hg(MBT)2] and bis(4-chlorothiophenolato) mercury(II) [Hg(CTP)2] carriers are described. The electrodes were prepared by incorporating the ionophores into plasticized PVC membranes, which were directly coated on the surface of graphite disk electrodes. The electrodes displayed high selectivity for iodide with respect to a number of inorganic and organic anions. The influence of the membrane composition and pH, and the effect of lipophilic cationic and anionic additives on the response properties of the electrodes were investigated. The electrodes exhibited near-Nernstian slopes of -57.6 ± 0.8 and -58.4 ± 1.4 mV/decade of iodide concentration over the range 1 × 10-6 – 1 × 10-1 M, with detection limits of ~4 × 10-7 and 6 × 10-7 M for the electrodes based on [Hg(MBT)2] and [Hg(CTP)2], respectively. They have relatively fast response times (≤ 10 s), satisfactory reproducibility, and life times of at least two months. The potentiometric responses of the electrodes are independent of pH of the test solution over the range 3.5 – 11.5.
Potentiodynamical Research of Zn-Al-Mg Alloy System in the Neutral Ambience of NaCl Electrolyte and Influence of Mg on the Structure  [PDF]
Reza Amini, Ziadolla Obidov, Izatulla Ganiev, Mohammad Razazi
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2012, DOI: 10.4236/jsemat.2012.22017
Abstract: The results of anodic behavior of Zn5Al, Zn55Al alloys alloyed with Magnesium in the environment and their micro-structures are studied. A potentiodynamical research carried out by Zinc-Aluminum alloys, alloyed with Magnesium obtained a corrosion-resistant coating with optimum concentration of Magnesium about 0.005 - 0.1wt%. The rate of corrosion of these alloys is 2 - 2.5 times lower than Zn5Al, Zn55Al initial alloys. It is explained by the effect of modification on the structure of original alloys and they can be used as an anticorrosion coating for protecting corrosion of steel frames.
Anodic Behavior of Zn-Al-Be Alloys in NaCl Solution and the Influence of Be on Structure  [PDF]
Reza Amini, Ziadolla Obidov, Izatulla Ganiev, Mohammad Razazi
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2012, DOI: 10.4236/jsemat.2012.22020
Abstract: Potentiodynamic results of anodic behavior of Zn5Al and Zn55Al alloys, alloyed with Beryllium in the ambience of NaCl electrolyte and their microstructures are studied. They showed that a small addition of Beryllium (0.005 - 0.05 wt%) improves the corrosion resistance of Zn5Al and Zn55Al original alloys to 2 - 3 times by changing grains shape to spherical and changing sizes to small grains. The proposed composition of Zinc-Aluminum alloy, which contains of Beryllium, can be used as anodic coatings to protect steel products and constructions against corrosion.
Maternal Serum Screening for Down Syndrome: Effect of Different Set of Distribution Parameters on Efficacy and Reliability of System
Mohammad Rahbar,Hamed Yahyazade,Rana Amini
Research Journal of Biological Sciences , 2012, DOI: 10.3923/rjbsci.2010.395.399
Abstract: The researchers tried to use the result of multiple markers assays in maternal serum to establish a mathematical method for calculating the risk of carrying a fetus with Down syndrome. This screening method is dependent on distribution of few parameters. We investigated the effect of different set of parameters on screening system. The most popular protocol for triple marker screening of Down syndrome is based on multivariate gaussian distribution. This study has been applied in a private medical laboratory. The result of different set of distribution of parameters on efficacy and reliability of system is investigated by graphical display and simulation by monte carlo method. In some cases, different sets of parameters in protocols make calculated risk inappropriately different. In some ranges of biochemical markers, the behavior of system violates their general trends on risk calculation. We found inherent error in models. This could be explained by interaction and value of distribution of parameters. We show effect of distribution of parameters in mathematical model, estimate efficacy of system and also emphasize on quality of parameters.
Using Animal Manure for Improving Soil Chemical Properties under Different Leaching Conditions
Mohammad Reza Mahmoodabadi,Sevda Amini,Kobra Khazaeipoul
Research Journal of Soil and Water Management , 2013, DOI: 10.3923/rjswm.2010.34.37
Abstract: Lack of adequate Organic Matter (OM) in the agricultural soils of Iran is responsible for the poor physic-chemical condition of these soils. Thus, increasing soil OM via. Manure application has an important function in improving the soil fertility. To enhance animal productivity and maximize economic returns, mineral salts are routinely added to animal feed worldwide. Salinity induced by manure application and chemical composition of soil and plant after its usage was investigated. The main purpose of this greenhouse study was to evaluate the impact of sheep manure and leaching of manure on growth, nutrient concentration and some chemical properties of soil. Leaching of some manure with 1:10 manure-water ratio was done because reducing of its salinity. Treatments consisted of four levels of sheep manure (0, 1, 2 and 4% based on dry weight) and two levels of manure leaching (with and without leaching). The results have shown that the application of sheep manure significantly increased N, Fe, Cu, Zn and Mn concentrations of soybean roots. Also, manure leaching reduced the negative effects of salinity-induced in 2% treatments. The effect of leaching on the root nutrients concentration was not consistent. Due to the lack of information on the effect of leaching on the growth of soybean it is recommended to study the effect of different levels of organic wastes leaching on more varieties of soybean in different soils.
Small Semi-Circle-Like Slot Antenna for Ultra-Wideband Applications
Farooq Amini;Mohammad Naghi Azarmanesh;Mouhammad Ojaroudi
PIER C , 2010, DOI: 10.2528/PIERC10022804
Abstract: In this paper, a small modified circle-like slot antenna with modified radiating patch, for UWB applications is proposed. The proposed antenna consists of a modified radiating patch with novel notch and a semi-circle-like with a slope which provides a wide usable fractional bandwidth of more than 135% (3.07-16.26 GHz). By optimizing the notched radiating patch, the total bandwidth of the antenna is greatly improved. The designed antenna has a small size of 27.5×27.5 mm.
Comparison of APACHE II, Adjusted APACHE II and TRISS Scores in Predicting Mortality Rate in Head Trauma Patients Admitted to ICU at Khatam-al-Anbia Hospital of Zahedan
Amini Shahram,Safari Malekabadi Mohammad,Roudbari Masoud
Zahedan Journal of Research in Medical Sciences , 2009,
Abstract: Background: Head trauma is a common and potentially fatal injury. Various models such as APACHE II, simplified APACHE (SAPA II), MPM II, and TRISS have been proposed to predict mortality in these patients. In this study, we compared the efficacy of APACHE II, adjusted APACHE II and TRISS models in predicting the mortality rate and quality of provided services in head trauma patients.Materials and Methods: In this retrospective cross sectional study, we calculated the APACHE II and TRISS scores, and predicted mortality rate by each model as well as predicted rate of adjusted APACHE II in head trauma patients admitted to a general ICU at Khatam-al-Anbia hospital of Zahedan from June 2006 to June 2007. The discriminating power of the models to predict the mortality rates were then measured and compared using area under ROC curve and z statistics, respectively. P value less than 0.05 was considered statistically significant.Results: Fifty six patients were included in this cross-sectional study. Of these, there were 49 men and 7 women with the mean age of 24.4 years. The mean duration of ICU admission was 10.07±6.40 days and 11 patients (19.6%) passed away. The mean APACHE II and TRISS scores were 44.78±5.13 and 18.75±8.79, respectively. The comparison between the APACHE II and adjusted APACHE II (P value = 0.8), APACHE II and TRISS (P value=0.2), and adjusted APACHE II and TRISS (P value=0.25) showed no significant difference. Discussion: Our study revealed that APACHE II predicted the mortality rates better than adjusted APACHE II and TRISS models in head trauma patients admitted to ICU but this priority was not statistically significant.
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