Fuzzy absolute error distance measure based on a generalised difference operation

The main goal of this paper is to introduce a notion of fuzzy absolute error distance measure between two fuzzy numbers. For this purpose, a notion of generalised difference operation between two fuzzy numbers and absolute value of a fuzzy number was first introduced. The proposed methods were conducted on the basis of α-values of fuzzy numbers. Main properties of the proposed fuzzy distance measure was also verified in the space of fuzzy numbers. The proposed fuzzy distance measure evaluates the fuzzy distance between the two fuzzy numbers as a fuzzy number. Notably, the main advantage of such generalised difference operation is that it always exists. Therefore, it improves the shortcoming of a well-known generalised difference operation called Hakuhara difference. Some of the main properties of the proposed fuzzy absolute error distance measure including robustness were also studied in the space of fuzzy numbers. Several fuzzy distance measures, especially fuzzy absolute error distance, have been proposed so far. However, none of them save all reasonable properties required for an absolute error distance measure in fuzzy environment. Shortcomings relevant to other methods and advantages of the proposed method were also discussed.     

A green and efficient synthesis of 2-thioxoquinazolinone derivatives in water using potassium thiocyanate

Green chemistry is one of the most important routes for the synthesis of heterocyclic compounds. In this regard, the synthesis of 2-thioxoquinazolinone derivatives was achieved by condensation of versatile materials including isatoic anhydride, amine and potassium thiocyanate in the green medium of water. This convenient and ef?cient method affords the desired products with good to excellent yields.     

Correlation between irregular surface geometry and certain electrochemical quantities in poly-ortho-aminophenol

The relationship between the fractal dimension of poly-ortho-aminophenol film and its thickness in the presence of different anions was studied using the peak current scaling in cyclic voltammetry (CV). There is a meaningful relation between the inner and outer cutoff (minimum and maximum length scale of the surface seen by the diffusing species, respectively) distinction in the polymer sensed by anions and the film charge transport resistance. The constant phase element exponent at low frequency was found to depend on the thickness of the poly-ortho-aminophenol film and on the applied potential during the impedance measurements. The constant phase element exponent dependence on the thickness of the film is explained by the film morphology and its dependence on the applied potential is interpreted by a change in the charge transport mechanism in the poly-ortho-aminophenol films.     

Synthesis and characterization of porous nanostructured Ni/PdNi electrode towards electrooxidation of borohydride

An electrochemical approach to nanostructured Ni/PdNi catalyst design using the electrodeposition process and galvanic replacement technique is presented. The procedure consisted of the electrodeposition of Ni–Zn on the Ni coating, with subsequent replacement of the zinc by palladium at open circuit in a palladium containing alkaline solution. The surface morphologies and compositions of coatings were determined by energy dispersive X-ray and scanning electron microscopy techniques. The results showed that the Ni/PdNi coatings were porous, and composed of discrete Pd nanoparticles with the crystallite size of about 58 nm. The electrocatalytic activity of Ni/PdNi electrodes towards electrooxidation of borohydride was studied using cyclic voltammetry and electrochemical impedance spectroscopy techniques. The anodic peak current density was found to be up to eight times higher on Ni/PdNi electrode for sodium borohydride compared to that for flat palladium. Therefore, the Ni/PdNi catalysts can be potential anode catalysts for the direct borohydride fuel cell.     

Preparation of thermoplastic elastomer nanocomposites based on polyamide‐6/polyepichlorohydrin‐co‐ethylene oxide

This work is aimed at determining the effect of nanoclay and polyepichlorohydrin‐co‐ethylene oxide (ECO) content on the microstructure and mechanical properties of PA6/ECO thermoplastic elastomers (TPEs). TPE nanocomposites were prepared in a laboratory mixer using polyamide 6 (PA6), ECO, and an organoclay by a two‐step melt mixing process. First, the PA6 was melt blended with Cloisite 30B and then mixed by ECO rubber. X‐ray diffraction results and transmission electron microscopy image showed that the nanoclay platelets were nearly exfoliated in both the phases. The SEM photomicrograph of PA6 with ECO showed that the elastomer particles are dispersed throughout the polyamide matrix and the size of rubber particles is less than 3 μm. Introduction of organoclay in the PA6 matrix increased the size of dispersed rubber particles in comparison with the unfilled but otherwise similar blends. The nanoscale dimension of the dispersed clay results in an improvement of the tensile modulus of the nanocomposites. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

Preparation of carbon molecular sieve from lignocellulosic biomass: A review

A literature review on preparation of carbon molecular sieve (CMS) from lignocellulosic biomass is presented. The effect of various operation parameters such as pyrolytic temperature, flow rate of the carbonizing agent and time of pyrolysis on the carbonization of the lignocellulosic biomass as a carbon precursor was reviewed. Various physical and chemical processes for the activation of the biomass-based char and their effects on textural properties of the activated char were discussed. Conversion of activated chars to CMS as the final stage of the preparation process through different techniques of chemical vapor deposition (CVD) and controlled pyrolysis was assessed. Survey of literature revealed that production of CMS with BET surface area of 1247 m²/g and micropore volume of 0.51 cm³/g, under appropriate conditions has been reported. Also, maximum selectivity of 7.6 and 400 for separation of O₂/N₂ and CO₂/CH₄ was devoted to palm shell and coconut shell-based CMS, respectively.     

Preparation, characterization, and application of alkaline leached Ni/Zn–Ni binary coatings for electro-oxidation of methanol in alkaline solution

The Ni–Zn binary coating was electrochemically deposited on a copper electrode. Then, it was etched in a concentrated alkaline solution (30 wt% NaOH) to obtain a porous electrocatalytic surface suitable for methanol electro-oxidation in alkaline solution. The surface compositions of coatings before and after alkaline leaching were determined by atomic absorption spectroscopy and energy dispersive X-ray analysis. The surface morphologies were investigated by scanning electron microscopy. It was found that the leached Ni–Zn coating has a porous structure. Electrocatalytic activity toward the methanol electro-oxidation was assessed by cyclic voltammetry and electrochemical impedance spectroscopy techniques. The activation of electrode related to the removal of existing corrosion products and formation of pores and cracks during alkaline leaching. Cyclic voltammetry studies confirmed that the alkaline leaching process improved the activity of Ni–Zn coating in comparison with smooth Ni deposit for the methanol electro-oxidation.     

Finite element modeling of the flow of a rubber compound through an axisymmetric die using the CEF viscoelastic constitutive equation

This work is devoted to the simulation of the flow of a high viscosity NR/SBR rubber compound through the die of a single screw extruder with axisymmetric geometry. An in-house developed computer code based on the use of continuous penalty finite element method was employed. Three constitutive equations including two generalized Newtonian models namely; power-law and Carreau and an explicit viscoelastic model named CEF (Criminale-Ericksen-Fillbey) were used to reflect the rheological behavior of the material. Using the parameters of the rheological models determined by a slit die rheometry technique, the flow of the compound was simulated through the die and results were compared with experimentally measured mass flow rates. It is shown that for high viscosity rubber compounds the use of generalized Newtonian models which do not take the normal stress in simple shear flow into consideration gives rise to significant errors in prediction of mass flow rates. On the other hand, comparing the simulations results using the CEF equation with experimental data revealed that this model is the best compromise between generalized Newtonian and full viscoelastic models which need high computational costs and effort. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012