La and Zn promotion of Ru Fischer-Tropsch catalysts

An investigation of the use of La- and Zn-promoters for Ru/SiO₂ F-T catalysts has been carried out. It was found that, while the use of a La-promoter did not result in any improvement over the use of a K one, Zn-promotion resulted in much higher yields of olefins. The CH₄ and olefin selectivities of the Zn-promoted Ru/SiO₂ were essentially insensitive to temperature over the range 250–320 °C. The Zn-promoted catalyst was found to have many of the same catalytic properties previously found for Ru/ZnO, but was much more active. Thus, it is possible to achieve certain interesting catalytic properties for Ru by the use of Zn-promotion without having to make use of the low surface area support ZnO.

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La Zn- Ru/SiO₂ F-T. , , La- - , Zn- . CH₄ Zn- Ru/SiO₂ , -, 250–320°C. Zn- , Ru/ZnO, . Ru, Zn- ZnO .

     

Decomposition rates of radiopharmaceutical indium chelates in serum

The rates at which six small aminopolycarboxylate chelates of trivalent¹¹¹In and three protein-bound chelates of¹¹¹In deliver indium to the serum protein transferrin have been studied in sterile human serum at pH 7.3, 37°C. Sterically hindered chelates containing a substituent on an ethylene carbon of EDTA decompose with rates in the range 0.03 to 0.11% per day—one to two orders of magnitude slower than other chelates. Only small differences are observed between rates of decomposition for low-molecular-weight chelates and for protein-bound chelates having analogous structures.     

Surface reaction and transport in mixed conductors with electrochemically-active surfaces: a 2-D numerical study of ceria

A two-dimensional, small-bias model has been developed for describing transport through a mixed ionic and electronic conductor (MIEC) with electrochemically-active surfaces, a system of particular relevance to solid oxide fuel cells. Utilizing the h-adaptive finite-element method, we solve the electrochemical potential and flux for both ionic and electronic species in the MIEC, taking the transport properties of Sm(0.15)Ce(0.85)O(1.925-δ) (SDC15). In addition to the ionic flux that flows between the two sides of the cell, there are two types of electronic fluxes: (1) cross-plane current that flows in the same general direction as the ionic current, and (2) in-plane current that flows between the catalytically-active MIEC surface and the metal current collectors. From an evaluation of these fluxes, the macroscopic interfacial resistance is decomposed into an electrochemical reaction resistance and an electron diffusion-drift resistance, the latter associated with the in-plane electronic current. Analysis of the experimental data for the interfacial resistance for hydrogen electro-oxidation on SDC15 having either Pt or Au current collectors (W. Lai and S. M. Haile, J. Am. Ceram. Soc., 2005, 88, 2979-2997; W. C. Chueh, W. Lai and S. M. Haile, Solid State Ionics, 2008, 179, 1036-1041) indicates that surface reaction rather than electron migration is the overall rate-limiting step, and suggests furthermore that the surface reaction rate, which has not been directly measured in the literature, scales with pO2(-1/4). The penetration depth for the in-plane electronic current is estimated at 0.6 μm for the experimental conditions of interest to SDC15, and is found to attain a value as high as 4 μm within the broader range of computational conditions.     

Development of PCR internal controls for DNA profiling with the AmpFℓSTR® SGM Plus® amplification kit

Forensic DNA profiling uses a series of commercial kits that co‐amplify several loci in one reaction; the products of the PCR are fluorescently labelled and analysed using CE. Before CE, an aliquot of the PCR is mixed with formamide and an internal lane size standard. Using the SGM Plus amplification kit, we have developed two internal non‐amplified controls of 80 bp and 380 bp that are labelled with ROX fluorescent dye and added to the PCR. Combined with two internal amplification controls of 90 bp and 410 bp, they provide additional controls for the PCR, electrokinetic injection, and CE and also function as an internal size standard.     

A fractional differential equation for a MEMS viscometer used in the oil industry

A mathematical model is developed for a micro-electro-mechanical system (MEMS) instrument that has been designed primarily to measure the viscosity of fluids that are encountered during oil well exploration. It is shown that, in one mode of operation, the displacement of the device satisfies a fractional differential equation (FDE). The theory of FDEs is used to solve the governing equation in closed form and numerical solutions are also determined using a simple but efficient central difference scheme. It is shown how knowledge of the exact and numerical solutions enables the design of the device to be optimised. It is also shown that the numerical scheme may be extended to encompass the case of a nonlinear spring, where the resulting FDE is nonlinear.     

On changing highest weight theories for finite W-algebras

A highest weight theory for a finite W-algebra $U(\mathfrak{g},e)$ was developed in Brundan et al. (Int. Math. Res. Not. 15:rnn051, 2008). This leads to a strategy for classifying the irreducible finite dimensional $U(\mathfrak{g},e)$ -modules. The highest weight theory depends on the choice of a parabolic subalgebra of $\mathfrak{g}$ leading to different parameterizations of the finite dimensional irreducible $U(\mathfrak{g},e)$ -modules. We explain how to construct an isomorphism preserving bijection between the parameterizing sets for different choices of parabolic subalgebra when $\mathfrak{g}$ is of type A, or when $\mathfrak{g}$ is of types C or D and e is an even multiplicity nilpotent element.     

Models for capacitated lot-sizing problem with backlogging,setup carryover and crossover

Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.     

Richardson Elements for Parabolic Subgroups of Classical Groups in Positive Characteristic

Let G be a simple algebraic group of classical type over an algebraically closed field k. Let P be a parabolic subgroup of G and let be the Lie algebra of P with Levi decomposition , where is the Lie algebra of the unipotent radical of P and ł is a Levi complement. Thanks to a fundamental theorem of Richardson (Bull. London Math. Soc. 6:21–24, 1974), P acts on with an open dense orbit; this orbit is called the Richardson orbit and its elements are called Richardson elements. Recently Baur (J. Algebra 297(1):168–185, 2006), the first author gave constructions of Richardson elements in the case for many parabolic subgroups P of G. In this note, we observe that these constructions remain valid for any algebraically closed field k of characteristic not equal to 2 and we give constructions of Richardson elements for the remaining parabolic subgroups. Presented by Peter Littelmann.