CH_4 reforming with CO_2 for syngas production over La_2O_3 promoted Ni catalysts supported on mesoporous nanostructured γ-Al_2O_3

Nanostructured γ-Al2O3 with high surface area and mesoporous structure was synthesized by sol-gel method and employed as catalyst support for nickel catalysts in methane reforming with carbon dioxide. The prepared samples were characterized by XRD, N2adsorption-desorption,TPR, TPO, TPH, NH3-TPD and SEM techniques. The BET analysis showed a high surface area of 204 m2 g-1and a narrow pore-size distribution centered at a diameter of 5.5 nm for catalyst support. The BET results revealed that addition of lanthanum oxide to aluminum oxide decreased the specific surface area. In addition, TPR results showed that addition of lanthanum oxide increased the reducibility of nickel catalyst. The catalytic evaluation results showed an increase in methane conversion with increasing lanthanum oxide to 3 mol% and further increase in lanthanum content decreased the catalytic activity. TPO analysis revealed that the coke deposition decreased with increasing lanthanum oxide to 3 mol%. SEM and TPH analyses confirmed the formation of whisker type carbon over the spent catalysts. Addition of steam and O2 to dry reforming feed increased the methane conversion and led to carbon free operation in combined processes.     

Invariant Pseudolinearity with Applications

In this paper, we introduce the notion of invariant pseudolinearity for nondifferentiable and nonconvex functions by means of Dini directional derivatives. We present some characterizations of invariant pseudolinear functions. Some characterizations of the solution set of a nonconvex and nondifferentiable, but invariant, pseudolinear program are obtained. The results of this paper extend various results for pseudolinear functions, pseudoinvex functions, and η-pseudolinear functions, and also for pseudoinvex programs, pseudolinear programs, and η-pseudolinear programs.     

Silica Sulfuric Acid: A Versatile and Reusable Catalyst for Synthesis of Coumarin-3-carboxylic Acids in a Solventless System

Synthesis of substituted coumarin-3-carboxylic acid via Knoevenagel condensation of meldrum's acid with ortho-hydroxyaryl aldehydes in solventless system is described.     

Thionine-functionalized graphene oxide,new electrocatalyst for determination of nitrite

In this work, thionine (Th) was assembled on the surface of graphene oxide as an electron transfer mediator using diazonium reaction (Th–GO). Then, Th–GO was characterized by different methods such as scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. Afterward, Th–GO was used for the modification of carbon paste electrode. Several electrochemical methods including cyclic voltammetry, differential pulse voltammetry, and hydrodynamic amperometry were used to investigate the behavior of the modified electrode. Then, the role of the modified electrode for oxidation of nitrite has been studied. For this purpose, the effect of critical experimental parameters including step potential and pulse amplitude (in differential pulse voltammetry technique), applied potential, the rotating speed of the disk (in amperometry technique), and the solution pH was investigated. Under the optimized conditions, the currents were found to be linear with the nitrite concentration in the range 0.05–33.0 and 0.5–800 µmol L^?1 with detection limits of 0.02 and 0.2 µmol L^?1 using differential pulse voltammetry and hydrodynamic amperometry, respectively. The introduced modified electrode showed good repeatability (RSD% = 3.2) and reproducibility (RSD% = 4.7). This electrochemical sensor was exerted successfully for the determination of nitrite and nitrate in real samples including water and wastewater samples.     

Homogeneous Liquid–Liquid Microextraction Via Flotation Assistance (HLLME-FA) Method for the Pretreatment of Organochlorine Pesticides in Aqueous Samples and Determination by GC–MS

This work proposes a new, rapid and simple homogeneous liquid–liquid microextraction via flotation assistance technique for the analysis of six organochlorine pesticides in water samples. A special extraction cell was used to facilitate collection of the low-density solvent extract. No centrifugation was required in this procedure. Determination was carried using gas chromatography–mass spectrometry. The water sample solution was then added into the extraction cell containing appropriate mixture of extract and homogeneous solvents. In the first step, a homogeneous solution and then with the continuation of water sample injection, a cloudy solution was formed. Using air flotation, the organic solution was collected at the conical part of the designed cell. The optimized levels of effective parameters were found based on response surface methodology approach. Applying the optimized conditions to the system understudy, the limits of detection of all target analytes were obtained in the range of 1.4–7 ng mL^?1, while the precisions were found to be in the range of 11.08–14.87 (RSD, n = 3). The linearity of the method lay in the range of 10–150 ng mL^?1 with the coefficients of correlation (r ² ) ranging from 0.998 to 0.999.     

Synthesis of Diaryl Ethers Through the Copper-Catalyzed Arylation of Phenols with Aryl Iodides Using KF/Al2O3

An efficient synthesis of diaryl ethers by the copper-catalyzed arylation of phenols with a variety of aryl iodide susing KF/Al₂O₃ as a suitable base and CuI and 1,3 diphenyl-1,3 propandione as the catalyst is described.     

溶胶-凝胶新方法合成介孔铁酸铜纳米粉体催化剂上CO低温氧化(英文)

Mesoporous CuFe2O4 solid solution nanopowders with high specific surface areas were synthesized by a novel, very simple and inexpensive sol-gel route using propylene oxide as gelation agent, and used as the catalyst in low temperature CO oxidation. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, thermogravimetric/differential thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and temperature-programmed reduction. The results revealed that the samples have a nanocrystalline structure with crystals in the range of 10 to 25 nm, and that all the catalysts have mesoporous pores. The addition of Cu into iron oxide affected its structural and catalytic properties. The sample containing 15 mol% Cu showed the highest specific surface area and catalytic activity, and showed high catalytic stability in low temperature CO oxidation.     

Developing Thermodynamic Micellization Approach to Model Asphaltene Precipitation Behavior

An little known yet significant issue in petroleum production processes in petroleum reservoirs is asphaltene precipitation/deposition. Asphaltene has not only a fuzzy and vague nature but it also can cause detrimental problems like reservoir blockage and, as a result, low oil recovery. To tackle this issue, many researchers have attempted to monitor asphaltene behavior versus thermodynamic conditions. A thermodynamic micellization approach is implemented in this work to describe asphaltene precipitation behavior for two sample fluids from Iranian reservoirs. First, the basic structures of the addressed approach and different contributions to Gibbs free energy of micellization proposed by Victorov and Firoozabadi (VF) are demonstrated. Second, a detailed sensitivity analysis with respect to the model parameters is performed by utilizing a new calculation strategy. Finally, a comparison between the predicted precipitation curve and the experimental one is illustrated; moreover, comparing our results with those reported by Victorov proves the superiority of the new strategy over the conventional one. The significance of this study shows the effect of each micellization parameter on the asphaltene precipitation behavior curve and illustrates the ability of the micellization approach evolved by VF in monitoring the effect of pressure on asphaltene precipitation using the new calculation procedure. Outcomes from this study could couple with commercial reservoir simulation software to improve precision and integrity for designing robust and effective production units.     

Application of a cohesive zone element for the prediction of damage in nano/micro coating

Many tools in production technology are nowadays coated to obtain a satisfactory lifetime and degradation resistance. Therefore, the main goal of this study is to investigate antiadhesive and wear resistant coatings made of ceramics, plastics and metals produced by High Power Pulsed Magnetron Sputtering (HPPMS) technique [1]. A cohesive zone element technique (CZ) is applied to model the interactions of the coatings and the substrate surfaces (see [2]). This goes along with the investigations of the delamination and failure behavior of the involved surfaces. To illustrate the applicability of the model, several structural simulations are performed. The developed CZ element model is capable of modeling the separation, the contact and also the irreversible reloading conditions in both normal and tangential directions [3]. The model is further developed to be applicable for different structures including different bonding behaviors, with a higher stability. The talk concludes with a detailed discussion of the numerical results of different material and interface properties. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)