On the reaction mechanism of CO2 reforming of methane over a bed of coal char

CO₂ reforming of methane was studied over a bed of coal char in a fixed bed reactor at temperatures between 1073 and 1223 K and atmospheric pressure with a feed composition of CH₄/CO₂/N₂ in the ratio of 1:1:8. Experimental results showed that the char was an effective catalyst for the production of syngas with a maximum H₂/CO ratio of one. It was also found that high H₂/CO ratios were favoured by low pressures and moderate to high temperatures. These results are supported by thermodynamic calculations. A mechanism of seven overall reactions was studied and three catalytic reactions of CH₄ decomposition, char gasification and the Boudouard reaction was identified as being of major importance. The first reaction produces carbon and H₂, the second consumes carbon, and the third (the Boudouard reaction) converts CO₂ to CO while consuming carbon. Equilibrium calculations and experimental results showed that any water present reacts to form H₂ and carbon oxides in the range of temperatures and pressures studied. Carbon deposition over the char bed is the major cause of deactivation. The rate of carbon formation depends on the kinetic balance between the surface reaction of the adsorbed hydrocarbons with oxygen containing species and the further dissociation of the hydrocarbon.     

Some Properties of Finite Morphisms on Double Points

For a finite morphism f : X Y of smooth varieties such that f maps X birationally onto X=f(X), the local equations of f are obtained at the double points which are not triple. If C is the conductor of X over X, and are the subschemes defined by C, then D and are shown to be complete intersections at these points, provided that C has the expected codimension. This leads one to determine the depth of local rings of X at these double points. On the other hand, when C is reduced in X, it is proved that X is weakly normal at these points, and some global results are given. For the case of affine spaces, the local equations of X at these points are computed.     

On a characterization of the essential spectra of the sum and the product of two operators

In this paper, we consider the sum and the product of two operators acting on a Banach space and we present some new and quite general conditions to investigate their Wolf, Schechter and Browder essential spectra.     

Holographic relation between p-adic effective action and string field theory

We consider two holographically related theories. As the first (d + 1)-dimensional theory, we consider a model in which the (d + 1)-dimensional space is the direct product of ? ^d and the half-axis ?₊ and in which the kinetic operator has a nonlocal term induced by the nonlocal kinetic operator of the p-adic effective action. It turns out that the kinetic operator in the second, holographically related, d-dimensional theory is the kinetic operator of the string field theory effective action.     

(1+1)-Correlators and moving massive defects

We study correlation functions of scalar operators on the boundary of the AdS₃ space deformed by moving massive particles in the context of the AdS/CFT duality. To calculate two-point correlation functions, we use the geodesic approximation and the renormalized image method, obtained from the traditional image method with the renormalization taken into account. We compare results obtained using the renormalized image method with direct calculations using tracing of winding geodesics around the cone singularities. Examples demonstrate that the results coincide. We show that correlators in the geodesic approximation have a zone structure, which depends substantially on the particle mass and velocity.     

Hybrid harmony search algorithm and fuzzy mechanism for solving congestion management problem in an electricity market

A hybrid technique for solving the congestion management problem in an electricity market based on harmony search algorithm (HAS) and Fuzzy mechanism is presented in this article. This algorithm does not require initial value setting for the variables and does not require differential gradients, thus it can consider discontinuous functions as well as continuous functions. The HAS is a recently developed powerful evolutionary algorithm, inspired by the improvisation process of musicians, for solving single/multiobjective optimization problems. In the proposed technique, each musician plays a note for finding a best harmony all together. Transmission pricing and congestion management are the key elements of a competitive electricity market based on direct access. They also focus of much of the debate concerning alternative approaches to the market design and the implementation of a common carrier electricity system. This article focuses on the tradeoffs between simplicity and economic efficiency in meeting the objectives of a transmission pricing and congestion management scheme. The effectiveness of the proposed technique is applied on 30 and 118 bus IEEE standard power system in comparison with CPSO, PSO‐TVAC, and PSO‐TVIW. The numerical results demonstrate that the proposed technique is better and superior than other compared methods. © 2015 Wiley Periodicals, Inc. Complexity 21: 90–98, 2016     

Hydrothermal-assisted sol–gel synthesis of Cd-doped TiO2 nanophotocatalyst for removal of acid orange from wastewater

Journal of Sol-Gel Science and Technology - This research is based on synthesis of titania (TiO2) nanophotocatalyst followed by cadmium (Cd) doping to activate the photocatalyst in visible part of...