13,309 research outputs found

    U(2,2) gravity on noncommutative space with symplectic structure

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    The classical Einstein's gravity can be reformulated from the constrained U(2,2) gauge theory on the ordinary (commutative) four-dimensional spacetime. Here we consider a noncommutative manifold with a symplectic structure and construct a U(2,2) gauge theory on such a manifold by using the covariant coordinate method. Then we use the Seiberg-Witten map to express noncommutative quantities in terms of their commutative counterparts up to the first-order in noncommutative parameters. After imposing constraints we obtain a noncommutative gravity theory described by the Lagrangian with up to nonvanishing first order corrections in noncommutative parameters. This result coincides with our previous one obtained for the noncommutative SL(2,C) gravity.Comment: 13 pages, no figures; v2: 14 pages, clarifications and references added; v3: 16 pages, title changed, clarifications and references added; v4: 17 pages, clarifications added, this final version accepted by Physical Review

    Seguimiento online de la conductividad eléctrica del vino inducido por ultrasonido

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    We assessed the effects of ultrasonic frequency, power, temperature and exposure time on the electric conductivity (EC) of wine to evaluate the feasibility of the online EC monitoring as an indicator to reflect the changes of wine quality under the ultrasound irradiation. Results showed that the continuously monitored curve of EC was significantly different from the values recorded at the beginning and end of sonication. An abrupt rise and a rapid drop of wine EC were observed at the start and end points of sonication, respectively, in all working conditions. With regards to the assayed wine temperatures, the effect exerted by this parameter on EC before sonication was totally different from that observed when the samples were cooled down after ultrasound treatment. All in all, these results suggest that the online EC monitoring of wine may be used as an efficient indicator to control and reflect the real changes of wine under ultrasound treatment.Hemos estudiado los efectos de la frecuencia de ultrasonido, la potencia, la temperatura y el tiempo de exposición en la conductividad eléctrica (EC) del vino para evaluar la viabilidad del seguimiento EC online como indicador para reflejar los cambios en la calidad del vino bajo irradiación de ultrasonido. Los resultados mostraron que la curva de EC supervisada en continuo fue significativamente diferente de los valores registrados al principio y al final de la sonicación. Se observaron un aumento brusco y una rápida caída de EC del vino al principio y al final de la sonicación, respectivamente, para todas las condiciones estudiadas. En referencia a las temperaturas testadas del vino, el efecto ejercido por este parámetro en EC antes de la sonicación fue totalmente distinto de aquel observado cuando se enfriaron las muestras después del tratamiento de ultrasonido. En resumen, estos resultados sugieren que el seguimiento online de EC del vino podría ser utilizado como un indicador eficiente para controlar y reflejar los cambios reales en el vino con el uso de tratamiento de ultrasonido.National Natural Science Foundation of China [grant number 31101324]Natural Science Foundation of Shaanxi Province, China [grant number 2015JM3097]Technology Transfer Promotion Project of Xi’an, Shaanxi Province, China [grant number CXY1434(5)]Fundamental Research Funds for the Central Universities of China [grant number GK201302039], [grant number GK201404006], [grant number GK201505128

    The Oblique Corrections from Heavy Scalars in Irreducible Representations

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    The contributions to SS, TT, and UU from heavy scalars in any irreducible representation of the electroweak gauge group SU(2)L×U(1)YSU(2)_L\times U(1)_Y are obtained. We find that in the case of a heavy scalar doublet there is a slight difference between the SS parameter we have obtained and that in previous works.Comment: 6 pages, 2 axodraw figures; minor changes, references update

    Research on Cascading Use of Waste Heat Technical Program in Heavy Oil Exploitation by SAGD Technology

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    AbstractIn Du 84 block Shu 1 area in Liaohe oilfield where used SAGD technology to exploit heavy oil, the temperature of wellhead produced fluid can reach up to 170-180°C, In view of this problem of wasting large amount of thermal energy, this paper proposes a set of technical program of cascading use of waste heat with the combination of generation of electrical energy and heating. Meanwhile, the generating capacity and heating area of the program as well as its economic efficiency are also calculated and analyzed. In addition, the parameters of generating system's condenser are optimized by taking the annual total cost of the condenser as the objective function and using majorized function fminsearch in MATLAB software, and the most superior technical parameters are determined. The result can offer some reference in using of waste heat in practical project
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