A Moving Grid Eulerian Lagrangian Localized Adjoint Method for Solving One-Dimensional Nonlinear Advection-Diffusion-Reaction Equations

We develop a moving grid Eulerian-Lagrangian Localized Adjoint Method (ELLAM) to solve the one-dimensional nonlinear Advective-Dispersive-Reactive Equation (ADRE) that governs contaminant transfer with biological/chemical/radioactive processes. The method uses a moving grid to define the solution and test functions. Consequently, the need for spatial interpolation, which is a major issue in conventional ELLAM formulations, is avoided. We apply the developed method for variable-coefficient ADRE with different time and spatial discretizations. Numerical experiments show the strength of the developed scheme. Accurate results are obtained even when using large time steps. In the last part of this paper, ELLAM is used to simulate the nonlinear ADRE that arises for reactive subsurface transport with biodegradation.     

双金属镍-锰/γ-Al2O3催化剂对甲烷二氧化碳重整反应的影响 (cited: 1)

用浸渍法制备γ-Al₂O₃负载的Ni-Mn双金属催化剂．在500～700 oC按照17:17:2的CO₂/CH₄/N₂比例,以36 mL/min的载气流速进行甲烷二氧化碳重整反应, 利用甲烷二氧化碳的转化率、生成的合成气H₂/CO比例以及长期稳定性等指标评价了催化剂的催化性能． 实验表明, 添加Mn提高催化性能并使双金属催化剂的稳定性更高, 比单金属催化剂更好地抑制焦炭生成,Mn最合适的添加量0.5wt％ ．通过BET、CO2-TPD、TGA、XRD、SEM、EDX和FTIR各种技术对催化剂进行了表征．     

Second-order BSDEs with general reflection and game options under uncertainty

The aim of this paper is twofold. First, we extend the results of Matoussi et al. (2013) concerning the existence and uniqueness of second-order reflected 2BSDEs to the case of two obstacles. Under some regularity assumptions on one of the barriers, similar to the ones in Crépey and Matoussi (2008), and when the two barriers are completely separated, we provide a complete wellposedness theory for doubly reflected second-order BSDEs. We also show that these objects are related to non-standard optimal stopping games, thus generalizing the connection between DRBSDEs and Dynkin games first proved by Cvitani? and Karatzas (1996). More precisely, we show under a technical assumption that the second order DRBSDEs provide solutions of what we call uncertain Dynkin games and that they also allow us to obtain super and subhedging prices for American game options (also called Israeli options) in financial markets with volatility uncertainty.     

Adsorption of Uranium (VI) Ions on Hydrazinyl Amine and 1,3,4-Thiadiazol-2(3 H)-thion Chelating Resins

Nitrogenous compounds are the most widely used in solid phase extraction due to its low cost, easy convertible to many functional groups. These have large adsorptive capacity toward heavy metal ions as rare earth elements (REEs) and uranium with ability for recovering from low concentrate solutions. Synthesis of resins were carried out by polymerization of acrylonitrile with divinyl benzene as crosslinker. Treatment of the resulted precipitate with hydrazine hydrate in ethanol produce hydrazinyl methyl amine which has high chelating capacity toward uranyl ions. 1,3,4-Thiadiazol-2(3H)-thion derivative was yielded by reaction of hydrazinyl amine with carbon disulfide in methanol. This reaction carried out in the presence of methyl benzoate and dioctyl phthalate as pore producing solvent which used to improve physical properties and adsorptive character of the resins. Optimization on the two resins during loading and elution were carried out using solution with different concentrations. The optimum factors during adsorption and elution were recognized.     

Synthesis and Spectroscopic Characterization of Novel Aryl-Dithiofluorophosphonate Derivatives and X-Ray Studies of [(4-CH3OC6H4)(F)P(S)S−][PH4P+]

Abstract

Potassium and tetraphenylphosphonium salts of novel aryldithiofluorophosphonic acids were synthesized. Lawesson's Reagent was allowed to react with KF in acetonitrile to yield the potassium salt of p-methoxyphenyldithiofluorophosphonic acid. Treatment of the latter with tetraphenylphosphonium chloride resulted in the formation of the tetraphenylphosphonium salt. The structures of the compounds were elucidated by FTIR, ¹H, ¹³C, ¹⁹F, and ³¹P NMR spectroscopy as well as by ESI-mass spectrometry. The molecular and crystal structure of the tetraphenylphosphonium salt, determined by single crystal X-ray diffraction, is also presented.

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