980 resultados para TEMPERATURE RANGE 0400-1000 K
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The incubation of seeds of Raphanus sativus L. cvar Early Scarlet Globe with 10 mu M aspirin resulted in increase in the temperature range for germination. The analysis of percentage germination and germination rates indicated the increase in the optimum temperature from 21.4 to 26 degrees C although at 32.6 degrees C 80.8% of seeds germinated with aspirin and no germination in the control. The analysis of the kinetics of seed germination indicated that aspirin treatment resulted in germination by decreasing the enthalpy of activation of the process. The aspirin treatment also resulted in the synchronization of seed germination. on the base of our results we propose aspirin application in practice to increase the tolerance to high temperature and to synchronize seed germination at least in Raphanus sativus L. cvar early scarlet globe.
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The effects of temperature on lung and blood gases were measured in the South American rattlesnake (Crotalus durissus terrificus). Arterial blood and lung gas samples were obtained from chronically cannulated animals at 15, 25, and 35 degrees C. As expected for reptiles, arterial pH fell with increased temperature (0.018 U degrees C-1 between 15 and 25 degrees C and 0.011 U degrees C-1 between 25 and 35 degrees C) while lung gas PCO2 rose from 5.8 mmHg at 15 degrees C to 13.2 mmHg at 35 degrees C. Concurrently, lung gas PO2 declined from 132 mmHg at 15 degrees C to 120 mmHg at 35 degrees C, and arterial PO2 increased from 33 to 76 mmHg in that temperature range. Arterial haemoglobin O-2 saturation rose from 0.53 at 15 degrees C to 0.83 at 25 degrees C but became slightly reduced (0.77) with a further elevation of temperature to 35 degrees C. Arterial haemoglobin concentration increased from 1.96 to 2.53 mM between 15 and 35 degrees C, consistent with higher demands on oxygen delivery to tissues at elevated temperatures. Moreover, the substantial increase of haemoglobin O-2 saturation between 15 and 25 degrees C conforms to the idea that reduction of the central vascular right-to-left shunt (pulmonary bypass of systemic venous return) is associated with high metabolic demands. (C) 1998 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Rate coefficients for direct radiative association of carbon and nitrogen atoms to form CN, and of carbon ions and nitrogen atoms to form CN+ ions, are calculated for temperatures in the range of 300 to 14,700 K. For the CN molecule, the rate coefficients can be represented by the standard expression, k(CN)(T) = 7.87 x 10(-19)(T/300)(0.056) exp (-96.0/T) cm(3) s(-1) for temperatures between 300 and 2700 K and k(CN)(T) = 1.37 x 10(-18)(T/300)-0.128 exp (-520.1/T) cm(-3) s(-1) at T > 2700 K. For the CN+ ion, the corresponding expression is k(CN+)(T) = 1.08 x 10(-18)(T/300)(0.071) exp (-57.5/T) cm(-3) s(-1) for the temperature range studied. Calculated rate coefficients k(CN) are about 2 orders of magnitude lower than the canonical value used in the modeling of the chemistry of various astrophysical environments.
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The rate coefficients for the formation of carbon monophosphide (CP) and silicon monophosphide (SiP) by radiative association are estimated for temperatures ranging from 300 to 14 100 K. In this temperature range, the radiative association rate coefficients are found to vary from 1.14 x 10(-18) to 1.62 x 10(-18) cm(3) s(-1) and from 3.73 x 10(-20) to 7.03 x 10(-20) cm(3) s(-1) for CP and SiP, respectively. In both cases, rate coefficients increase slowly with the increase in temperature.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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This work presents experimental information relevant to the combustion of biomass in a bubbling fluidized bed. The biomass distribution in a fluidized bed was studied through tests performed in a cold bed, while the volatiles released in the biomass pyrolysis, the burning rate of the resulting charcoal, and the combustion control regime, were studied through tests performed in a high temperature bed.Visual examination of photographs taken from a transparent walls bed, with a rectangular cross-section, showed that the large fuel particles, typical of biomass processing, were distributed in the bubbles, in the splash zone, and in the emulsion phase. The occurrence of biomass in the emulsion phase was favored by burning biomass particles of greater density and smaller size-expetimentally determined in each case. Decreasing the fuel particle size improved the biomass distribution inside the bed. The same was accomplished by increasing the superficial gas velocity as high as possible, compatibly with the acceptable elutriation.Burning tests showed that the biomass fuels have the advantage of reaching the diffusional regime at temperatures that can be lower than 1000 K, which ensures that the biomass fuels burn in a stable regime. (C) 2007 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)