Preparation of mesoporous nanocrystalline 10% Ni/Ce1−xMnx O2 catalysts for dry reforming reaction

Methane dry reforming (MDR) was employed for the syngas production over 10% Ni/Ce_1?xMn_xO₂ (x = 0, 0.05, 0.25, 0.50, 0.75 and 1) catalysts. The obtained results indicated that the incorporation of Mn to the cerium oxide improved the BET area. However, there was an optimum content of Mn, in which the composite material exhibited the highest BET area. Addition of Mn more than 50 mol.% declined the BET area and significantly raised the mean pore size. The catalytic results indicated that the incorporation of Mn into the catalyst carrier slightly decreased the catalytic activity. However, the catalytic stability improved upon the addition of Mn. The TPO analysis confirmed the decrease in the amount of deposited carbon with the increase of Mn content. The whisker type carbon was observed on the surface of the spent catalysts. The catalytic results showed that the 10% Ni/Ce_0.95Mn_0.05O₂ exhibited the highest catalytic performance in methane reforming with carbon dioxide.     

Enhanced activity of CO2 methanation over mesoporous nanocrystalline Ni–Al2O3 catalysts prepared by ultrasound-assisted co-precipitation method

The ultrasound-assisted co-precipitation method was employed for the synthesis of the Ni–Al₂O₃ catalysts with different metal loadings for the CO₂ methanation reaction. This study indicated that increasing the Ni loading up to 25 wt.% enhanced the surface area, decreased the crystallinity and improved the reducibility of the catalysts, while further raise in Ni loading adversely influenced the surface area. Improvements in catalytic performance were obtained with the raise in Ni content because of enhancing the BET area. The results confirmed that the 25Ni–Al₂O₃ catalyst with the highest BET area (188 m² g^?1) and dispersion of Ni has the highest catalytic activity in CO₂ methanation and reached to 74% CO₂ conversion and 99% CH₄ selectivity at 350 °C. In addition, this catalyst exhibited a great stability after 10 h time-on-stream.     

Prediction of the heat transfer rate of a single layer wire-on-tube type heat exchanger using ANFIS

In this paper, we applied an Adaptive Neuro-Fuzzy Inference System (ANFIS) model for prediction of the heat transfer rate of the wire-on-tube type heat exchanger. Limited experimental data was used for training and testing ANFIS configuration with the help of hybrid learning algorithm consisting of backpropagation and least-squares estimation. The predicted values are found to be in good agreement with the actual values from the experiments with mean relative error less than 2.55%. Also, we compared the proposed ANFIS model to an ANN approach. Results show that the ANFIS model has more accuracy in comparison to ANN approach. Therefore, we can use ANFIS model to predict the performances of thermal systems in engineering applications, such as modeling heat exchangers for heat transfer analysis.     

A fast response cadmium-selective polymeric membrane electrode based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide as a new neutral carrier

A new polyvinylchloride membrane sensor for Cd(2+) ions based on N,N'-(4-methyl-1,2-phenylene)diquinoline-2-carboxamide (Mebqb) as a new and excellent neutral ionophore has been prepared. The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0 x 10(-6) to 1.0 x 10(-1) M) with the determination coefficient of 0.9964 and slope of 29.9 +/- 0.5 mV decade(-1). The limit of detection is 8 x 10(-7) M. It has a fast response time of 3-8s and can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 4.0 to 9.0. The proposed sensor shows a very good discriminating ability towards Cd(2+) ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Cd(2+) in standard and real sample solutions.     

A simple and selective spectrophotometric flow injection determination of trace amounts of ruthenium by catalytic oxidation of safranin-O

In this work, a simple, selective and rapid flow injection method has been developed for determination of ruthenium. The method is based on its catalytic effect on the oxidation of safranin-O by metaperiodate. The reaction was monitored spectrophotometrically by measuring safranin-O absorbance at lambdamax=521. The reagents and manifold variables, which have influences on the sensitivity, were investigated and the optimum conditions were established. The optimized conditions made it possible to determine ruthenium in the ranges of 0.4-20.0 ng/mL (DeltaA=0.2819CRu+1.1840) and 20.0-100.0 ng/mL (DeltaA=0.0984CRu+7.9391) with a detection limit of 0.095 ng/mL and a sample rate of 30+/-5 samples/h. Relative standard deviation for the five replicate measurements was less than 1.84%. The proposed method has been successfully applied for analysis of ultra trace amounts of ruthenium in real samples.     

Changes in sialylation of low‐density lipoprotein in coronary artery disease

Reduction of LDL sialylation may correlate with coronary artery disease (CAD), but the details of this modification and its effect on CAD are not well studied. This study was aimed to show desialylation of LDL and to reveal more details of this modification. Blood samples were collected from 16 patients with CAD and 25 healthy individuals. Serum sialic acid was determined. LDL was extracted from all samples, and the interaction of the extracted materials with lectins (MAA, SNA, and DSA) was studied using the lectin blotting method. Serum total sialic acid (TSA) concentrations in CAD patients and healthy individuals were 71.9 ± 2.66 and 60.76 ± 2.34 mg/dL, respectively, and the difference between the two groups was statistically significant (p <0.001). The intensity of interaction of extracted LDL with SNA and MAA lectins was lower in CAD patients compared to that in normal subjects (p <0.001). The intensity of interaction of LDL with DSA was higher in CAD (p <0.001). There was a reverse correlation between TSA and intensity of LDL interaction with SNA and MAA in both groups, but in the case of DSA this correlation was direct and positive. These findings indicated an increase in desialylation of LDL in CAD. It was concluded that LDL was subjected to glycosylation changes in CAD and that there was a positive correlation between TSA and the desialylated form of LDL. This modification may contribute to the pathogenesis of CAD.     

Compatibility assessment of CVD growth of carbon nanofibers on bulk CMOS devices

We compare the level of deterioration in the basic functionality of individual transistors on ASIC chips fabricated in standard 130 nm bulk CMOS technology when subjected to three disparate CVD techniques with relatively low processing temperature to grow carbon nanostructures. We report that the growth technique with the lowest temperature has the least impact on the transistor behavior.     

Radiation‐induced graft copolymerization of MMA monomer onto UHMWPE: Adhesion improvement

Graft copolymerization of methyl methacrylate monomer onto ultra high molecular weight polyethylene (UHMWPE) and acid‐etched UHMWPE was conducted using preirradiation method in air in the presence of a Mohr salt and sulfuric acid to improve adhesion to the bone cement. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, gravimetric method, goniometry, and interfacial bonding strength measurements. The FTIR results showed the presence of ether, carbonyl, and hydroxyl groups for grafted films. The gravimetric results showed that the chromic acid etching and graft copolymerization had a synergetic effect so, the irradiated, then chromic acid etched at room temperature and grafted sample (Rad etch25) had the highest grafting degree. The interfacial bonding strength between UHMWPE and poly methyl methacrylate bone cement was considerably improved by graft copolymerization and chromic acid etching. The surface morphology was studied by scanning electron microscopy. The substitution of polar groups into the backbone of UHMWPE by chromic acid etching and graft copolymerization changed its contact angles with water and methylene iodide and increased its surface energy, as evidenced by contact angle measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Improvement of the Ohmic Loss Process Model of the Proton Exchange Membrane Fuel Cell

The impedance characteristics of the ohmic overpotential of the proton exchange membrane (PEM) fuel cells are studied analytically using the process modeling approach. The water transport in the membrane, the cathode catalyst layer, and gas diffusion layer are analyzed. The analytical relation of the impedance of the ohmic loss is determined and is converted to an equivalent circuit. Then, the impedance of a PEM fuel cell is measured experimentally in different current densities, operating temperatures and the anode and cathode relative humidities. The measured impedances are compared with the predicted ones from the analytical model. It is shown that the predicted impedance characteristics are in great agreement with the measured ones in all different operating conditions.