4,325 research outputs found

    The Imperial Presidency and Interventionism

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    Air bearing Patent

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    Air bearings for near frictionless transfer of loads from one body to anothe

    Preliminary Validation of the Spanish Version of the Multiple Stimulus Types Ambiguity Tolerance Scale (MSTAT-II)

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    Despite widespread interest in ambiguity tolerance and other informationrelated individual differences, existing measures are conceptually dispersed and psychometrically weak. This paper presents the Spanish version of MSTAT-II, a short, stimulus-oriented, and psychometrically improved measure of an individual’s orientation toward ambiguous stimuli. Results obtained reveal adequate reliability, validity, and temporal stability. These results support the use of MSTAT-II as an adequate measure of ambiguity tolerance.A pesar del amplio interés en la tolerancia a la ambigüedad y a otras diferencias individuales relacionadas con la información, las medidas existentes son conceptualmente dispersas y presentan deficiencias psicométricas. El propósito de este trabajo es presentar la versión española del MSTAT II, un instrumento de medida de las orientaciones de un individuo respecto a estímulos ambiguos con mejoras psicométricas sustanciales, independiente del contexto y suficientemente corto para ser utilizado junto con otras medidas. Los resultados obtenidos en cuanto a consistencia interna, estabilidad temporal y validez son satisfactorios. Estos resultados apoyan el uso del MSTAT-II en su versión española como una medida adecuada de tolerancia a la ambigüedad.Junta de Andalucía proyecto SEJ 267

    Computer predictions of photochemical oxidant levels for initial precursor concentrations characteristic of southeastern Virginia

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    A computer study was performed with a photochemical box model, using a contemporary chemical mechanism and procedure, and a range of initial input pollutant concentrations thought to encompass those characteristic of the Southeastern Virginia region before a photochemical oxidant episode. The model predictions are consistent with the expectation of high summer afternoon ozone levels when initial nonmethane hydrocarbon (NMHC) levels are in the range 0.30-0.40 ppmC and NOx levels are in the range 0.02-0.05 ppm. Calculations made with a Lagrangian model, for one of the previously calculated cases, which had produced intermediate afternoon ozone levels, suggest that urban source additions of NMHC and NOx exacerbate the photochemical oxidant condition

    Chemical kinetic modeling of propane oxidation behind shock waves

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    The stoichiometric combustion of propane behind incident shock waves was studied experimentally and analytically over a temperature range from 1700 K to 2600 K and a pressure range from 1.2 to 1.9 atm. Measurements of the concentrations of carbon monoxide (CO) and carbon dioxide (CO2) and the product of the oxygen atom and carbon dioxide concentrations (O)(CO) were made after passage of the incident shock wave. A kinetic mechanism was developed which, when used in a computer program for a flowing, reacting gas behind an incident shock wave predicted experimentally measured results quite well. Ignition delay times from the literature were also predicted quite well. The kinetic mechanism consisted of 59 individual kinetic steps

    Polynomial coefficients of thermochemical data for the C-H-O-N system

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    Thermodynamic data are required input for the finite kinetics and equilibrium computer programs needed for modeling the combustion of hydrocarbons in the fields of energy and pollution research. Least squares determined coefficients of the curve-fitted thermodynamic data for 193 species in the C-H-O-N system are presented in card image form and are of suitable format for use by common computer programs

    A Chemical Kinetic Mechanism for the Ignition of Silane/Hydrogen Mixtures

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    A chemical kinetic reaction mechanism for the oxidation of silane/hydrogen mixtures is presented and discussed. Shock-tube ignition delay time data were used to evaluate and refine the mechanism. Good agreement between experimental results and the results predicted by the mechanism was obtained by adjusting the rate coefficient for the reaction SiH3 + O2 yields SiH2O + OH. The reaction mechanism was used to theoretically investigate the ignition characteristics of silane/hydrogen mixtures. The results revealed that over the entire range of temperature examined (800 K to 1200 K), substantial reduction in ignition delay times is obtained when silane is added to hydrogen

    A hybrid computer program for rapidly solving flowing or static chemical kinetic problems involving many chemical species

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    A hybrid chemical kinetic computer program was assembled which provides a rapid solution to problems involving flowing or static, chemically reacting, gas mixtures. The computer program uses existing subroutines for problem setup, initialization, and preliminary calculations and incorporates a stiff ordinary differential equation solution technique. A number of check cases were recomputed with the hybrid program and the results were almost identical to those previously obtained. The computational time saving was demonstrated with a propane-oxygen-argon shock tube combustion problem involving 31 chemical species and 64 reactions. Information is presented to enable potential users to prepare an input data deck for the calculation of a problem
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