Tellurium/lithium exchange reactions in the synthesis of spiroketals and 1,6-dioxygenated systems

1,4-C,O-dianions have been generated through concomitant acid/base and tellurium/lithium exchange reactions. The di-lithium salts were transmetallated with cerium chloride to the corresponding di-cerium salts and subsequently reacted with lactones and carboxylic acid anhydrides to yield the respective spiroketals. The di-lithium entities were also converted into the corresponding cyanocuprates that add in a 1,4-manner to 2-cyclohexen-1-one to form 1,6-dioxygenated compounds.     

Development of an LC–DAD Method for Analysis of Dexketoprofen, Tramadol, and Haloperidol. Study of the Stability of Mixtures Used for Patient-Controlled Analgesia

A novel LC method was applied to enhance the peak resolution of two ecdysteroids: 20-hydroxyecdysone and its 3-epimer. An isocratic solvent system of methanol–water (6:4, v/v) was used on a C18 column, and 100 μL of water was injected during the development in such a manner that the eluted solvent peak appeared exactly between the two overlapping peaks. This resulted in the increased retardation of the later-eluted peak, and in a good separation of the two compounds within 4.5 min.     

Interactive method for computation of viscous flow with recirculation

An interactive method is proposed for the solution of two-dimensional, laminar flow fields with identifiable regions of recirculation, such as the shear layer driven cavity flow. The method treats the flow field as composed of two regions, with an appropriate mathematical model adopted for each region. The shear layer is computed by the compressible boundary layer equations, and the slowly recirculating flow by the incompressible Navier-Stokes equations. The flow field is solved iteratively by matching the local solutions in the two regions. For this purpose a new matching method utilizing an overlap between the two computational regions is developed, and shown to be most satisfactory. Matching of u, v, as well as u/y is amply accomplished using the present approach, and the stagnation points corresponding to separation and reattachment of the dividing streamline are computed as part of the interactive solution. The interactive method is applied to the test problem of shear layer driven cavity. The computational results are used to show the validity and applicability of the present approach.     

Methodology to determine stresses due to own weight by using residual stresses techniques

Experimental Techniques -     

Vibrational spectroscopy of indium-doped Pb0.9Mn0.1Te alloy

Raman scattering and far-infrared reflection spectra of 0.5 at.% In doped Pb_0.9Mn_0.1Te single crystal at temperatures between 10 and 300K are presented. The infrared spectra have been fitted using a modified plasmon-phonon interaction model with an additional oscillator (at about 122 cm^?1) representing a local In-impurity mode. Phonons in this mixed crystal exhibit intermediate mode behavior. The plasma frequency decreases on cooling from 300 to 25K and increases sharply between 20 and 10 K. The results of galvanomagnetic measurements are also presented.     

Molecular dynamics simulation of (100)InGaAs/GaAs strained-layer relaxation processes

Molecular dynamics simulations on In_1−xGa_xAs/GaAs(100) systems are performed showing the dynamics of threading dislocations in the overlayers and the formation of misfit dislocations at the heterojunction interface. The developed code, using a modified Tersoff potential, simulates the threading dislocation dynamics in the InGaAs overlayer, and also the formation of interface misfit dislocations. Values for critical thicknesses are predicted and the atomic structure of the dislocation cores are determined.     

New Product Evaluation Using a Bayesian Dynamic Program

A method of scheduling new product evaluation steps is proposed. The method presented offers promise in reducing the costs of this evaluation. The value of each evaluation is based on Bayesian methods.     

The analysis of risky portfolios by geometric programming

Summary The problem of selecting a portfolio from a set of risky business ventures is considered. It is formulated as a maximization of the risk-adjusted (certainty-equivalent) profit for the portfolio based upon the exponential utility function and analysed via generalised geometric programming. Generalised geometric programming provides dual programs for the general case and for particular probability distributions. The particular cases of gamma, binomial, and normal distributions are converted into duals which arc of one dimension regardless of the number of portfolios.

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Zusammenfassung Ausgangspunkt dieses Aufsatzes ist das folgende Portfolio-Problem: Ein gegebenes Budget ist auf verschiedene Anlagemöglichkeiten so aufzuteilen, daß dabei der erwartete Nutzen des Gesamtertrages maximiert wird. Dieses Problem wird — zunächst ohne Verwendung einer Wahrscheinlichkeitsverteilung für die Erträge der einzelnen Anlagemöglichkeiten — mit Hilfe der verallgemeinerten geometrischen Programmierung analysiert. Es werden duale Programme abgeleitet, die die Lösung des Portfolio-Problems für verschiedene spezielle Verteilungsfunktionen in sehr einfacher Weise gestatten.