Quantum effects in the Gowdy T3 cosmology

The Gowdy T³ Cosmology is an exact solution to the vacuum Einstein equations interpreted to be a single polarization of gravitational waves propagating in an anisotropic, spatially inhomogeneous background. The classical behavior is reviewed and related to standard cosmological parameters. Canonical quantization of the dynamical degrees of freedom is reviewed. An adiabatic vacuum state is constructed. Adiabatic regularization is used to obtain non-divergent stress-energy tensor vacuum expectation values. Casimir energy terms due to T³ imposed discrete modes are evaluated. The vacuum expectation values are analyzed in early and late time limits and evaluated numerically. The regularized expectation value is used as a source for the classical background spacetime in the spirit of semi-classical gravity. An entirely vacuum expectation value source term produces essentially the time reverse of the classical evolution. Classical stress-energy added to the source restores the classical behavior at late times only. The combined system collapses from infinite to small but non-zero volume and reexpands. The classical singularity is replaced by a symmetric bounce.     

Organometallic complex compounds,part 51. Ligand property controlled CO-insertion in nickel complexes: Separation of electronic and steric effects

Summary The influence of twenty phosphorus-containing ligands on the CO insertion with four-coordinated Ni¹¹ complexes as starting reagents is reported. Quantitative separation of the electronic and steric effects by a multilinear regression analysis (55% electronic and 45% steric influence) is presented together with a three dimensional representation. An increase in donor-capacity favours CO insertion and an increase in steric hindrance leads to a decrease in the fraction of the corresponding ketone.     

Statistical Decision Analysis of Cooperative Advertising Ventures

Statistical analysis is used for a decision situation involving a vertical cooperative advertising venture. A product is sold from a company to an independent agent, in which a portion of the agent advertising expense is paid by the company. A typical example is the company-to-agent relation between a soft drink manufacturer and its bottlers (distributors). The object of the analysis is to determine an optimal setting of the product price between company and agent, the advertising subsidy paid to the agent by the company and the advertising level of the agent. It is demonstrated via a real-world study that these decisions may be improved by use of statistical analysis.     

Numerical study of the unstable MHD spectrum of a small aspect ratio,flat current,non-circular tokamak

The Lausanne ideal MHD stability code ERATO is used to investigate spectral properties of Solovèv's equilibrium at small aspect ratios. Two different elongations are considered. Both free and rigid boundary models are computed and compared. Modes characterized by a large radial extension have been found which appear to be due to a coupling ofm=1 andm=2 modes due to toricity. The internal modes spectrum is compared with the predictions of the full mercier criterion, taking into account its spatial dependence, and with the ballooning modes stability criterion.

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Résumé Les propriétés spectrales des équilibres analytiques de Solov'èv à petit rapport d'aspect sont étudiées à l'aide du code numérique ERATO qui permet de calculer le spectre magnétohydrodynamique d'une configuration Tokomak quelconque. Nous avons examiné deux situations différentes: paroi conductrice collée contre la surface du plasma et vide infini ainsi que deux élongations. Nous avons trouvé que les modes instables ont une grande extension radiale, due au couplage torique entre les modesm=1 etm=2. Le spectre des modes internes est comparé aux prédictions du critère de Mercier, prenant en considération sa dépendance radiale. La limite de stabilité aux modes internes à basn est comprise entre la limite de Mercier correspondante et la limite ballooning.

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Presently at IBM Lausanne.

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Presently at General Atomics, San Diego.     

Dynamical violation of the Zweig rule and the energy dependence of π−p→ ϕn

The large magnitude and rapid decrease with energy of σ(π^?p→?n) in the momentum range < 6 GeV/c indicate a dynamical breaking of the Zweig rule. We provide an explicit box diagram amplitude for this process. Zweig's rule is obeyed exactly at all vertices. The size and rapid fall of the cross section are explained in terms of s channel thresholds and duality cancellations in the intermediate states of the box.     

Pulsed-field gradient nuclear magnetic resonance study of transport properties of fluid catalytic cracking catalysts

Pulsed-field gradient nuclear magnetic resonance (PFG NMR) has been applied to study molecular diffusion in industrial fluid catalytic cracking (FCC) catalysts and in USY zeolite for a broad range of molecular displacements and temperatures. The results of this study have been used to elucidate the relevance of molecular transport on various displacements for the rate of molecular exchange between catalyst particles and their surroundings. It turned out that this rate, which may determine the overall rate and selectivity of FCC process, is primarily related to the diffusion mode associated with displacements larger than the size of zeolite crystals located in the particles but smaller than the size of the particles. This conclusion has been confirmed by comparative studies of the catalytic performance of different FCC catalysts.