The Thioxophosphane H-P=S and Its Tautomer H-S-P, (Thiohydroxy) phosphinidene, are Stable in the Gas Phase -(confirmation by neutralization-reionization mass spectroscopy).-(WONG, T.; TER-LOUW, J. K.; KECK, H.; KUCHEN, W.; TOMMES, P.; J. Am. Chem. Soc. 114 (1992) 21, 8208-8210; Dep. Chem., McMaster Univ., Hamilton, Ont. L8S 4M1, Can.; EN)

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Homoallyl amines were synthesized by visible-light irradiation of CdS powder in the presence of N-phenylbenzophenone imine and cyclohexene, 2,3-dihydrofuran, 2,5-dihydrofuran, 3,4-dihydropyran, 2-pentene, cyclopentene, 1 -methylcyclohexene, or a-pinene. The structures of the products from the last three olefins were determined by singlecrystal X-ray analysis to prove that C-alkylation of the imine had occurred. Thus, the reaction is formally an insertion of the imine into an allylic C-H bond of the olefin. It is proposed that a photogenerated electron-hole pair reduces the imine to an a-aminodiphenylmethyl radical and oxidizes the olefin with concomitant deprotonation to the corresponding allyl radical. Heterocoupling of these in-

Using the technique of neutralization-reionization mass spectrometry (NRMS) we have shown that the elusive thioxophosphane H-P=S and its tautomer H-S-P, (thiohydroxy)phosphinidene, are stable molecules in the gas phase.H-S-P"+ radical cations, generated by electron impact ionization of diethylphosphine sulfide, (C2H5)2HP=S, are cleanly reduced to H-S-P; whereas H-P=S"' anions, generated in a negative chemical ionization (NCI) experiment with the diethylphosphine sulfide, are readily oxidized to H-P=S. Double collision experiments on the 34S isotopomers of the two tautomeric species were used to confirm the connectivity of the atoms. H-S-P is the first example of a molecule of the composition "XPS" (e.g., X = F, Cl, or Br) in which P does not take the central position.

This article gives an overview of the current methods for life cycle analysis with special emphasis on dynamic load analysis. Recent developments in CFD simulations of time-dependent phenomena are presented, such as the von Kármán vortex shedding at stay vanes in a Kaplan turbine and the part load vortex in the draft tube of a Francis turbine and a pump turbine. A major topic of this article is the unsteady pressure field in a pump turbine, which is caused by the interaction of guide vanes and runner blades. CFD results of the pressure pulsations and their validation through comparison with measurement data are presented. It is shown how the predicted time-dependent pressure load is transferred as input to the structural analysis of the runner. For the analysis of the response of the runner to the dynamic load knowledge of the natural frequencies of the structure is required including the influence of the surrounding water on the natural frequencies. New results of the prediction of the natural frequencies of a Francis runner including the added mass effect due to the surrounding water are presented. For Pelton runners the state-of-the-art of measurement of eigenfrequencies and detuning are discussed along with the potential improvements due to the new simulation methods.