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131.
An approximate solution for the slow motion of an ensemble of spherical drops through a power law fluid is obtained using Happel's free-surface cell model. It is shown that the drag coefficient decreases with decrease of the flow index and that this reduction is more significant at low voidage and large viscosity ratio parameter. The effect of the pseudoplastic anomaly on the mass transfer rate is more pronounced at low voidage for large values of viscosity ratio parameter, unlike the case of a single spherical drop
The present analysis covers the whole range of values of viscosity ratio parameter from infinity (an assemblage of solid spheres) to zero (a swarm of bubbles) and reduces to the solutions for those cases already known
The results for the motion of an ensemble of spherical drops also provide the basis for proposing a tentative expression for the expansion of liquid-liquid fluidized bed at low Reynolds number. 相似文献
The present analysis covers the whole range of values of viscosity ratio parameter from infinity (an assemblage of solid spheres) to zero (a swarm of bubbles) and reduces to the solutions for those cases already known
The results for the motion of an ensemble of spherical drops also provide the basis for proposing a tentative expression for the expansion of liquid-liquid fluidized bed at low Reynolds number. 相似文献
132.
133.
The report illustrates secular changes in the development of body height and mass in Lód? school children and youths in a period of time covering 65 years between 1930-1994. The lowest values of both traits were found in the early post-war period (1948-1949) increasing gradually until the end of the seventies. From that time the secular trend diminished successively, restraining completely in the last years (1992-1994). This seems to be connected with the economic crisis of the eighties in Poland, and the deep transformation of socio-economic relations in the last several years. According to the secular changeability values, the rate of that process in relation to younger groups of children increases considerably from the 12th year of life. The biggest changes (in centimeters and kilograms per decade) can be observed in the age of 15 and 16 years. Usually more distinctive variableness is apparent in boys than in girls. 相似文献
134.
M. Malinowski I. Pracka B. Surma T. ?ukasiewicz W. Woliński R. Wolski 《Optical Materials》1996,6(4):305-312
The spectroscopic properties of trivalent praseodymium (Pr3+) doped SrLaGa3O7 (SLG) crystals have been investigated at various temperatures. Absorption, emission, excitation and lifetime measurements have been performed and discussed in the framework of the Judd-Ofelt approach. Stimulated emission cross sections for the strongest transitions of Pr3+ ion have been calculated. Stimulated emission has been observed for the first time in Pr3+ doped SLG crystal, we have obtained laser operation at 488 n, at cryogenic temperatures and at 645 nm at room temperature. 相似文献
135.
Pawe? Malinowski 《International Journal of Refrigeration》2011,34(4):968-979
This article presents the application of a neural model of heat transfer for the purpose of forecasting temperature at selected points of a circulating water ring network. The purpose of a circulating water system is to lower the temperature of petroleum products manufactured on numerous petrochemical lines at a Polish petrochemical plant. Temperature forecasting at 96 nodes of the circulating water system, significant from the point of view of system operation, is carried out using SVM neural networks. Neural networks learn based on archival data recorded in the process parameter monitoring system. Thermal, hydraulic and control parameters of the cooling process, as well as weather variables, constitute crucial input data for the neural model. The temperature forecasting algorithm has been implemented in a computer program that was then applied and remains in use for temperature forecasting in a maintenance department of an industrial plant. 相似文献
136.
W. Gryk B. Kukli
ski M. Grinberg M. Malinowski 《Journal of Alloys and Compounds》2004,380(1-2):230-234
Absorption, emission, and luminescence excitation spectra of the LiNbO3 crystal doped with 0.5% Pr3+ and 0.8% Yb3+ are presented. Additionally the photoluminescence spectra at high pressure have been measured. Hydrostatic pressures up to 135 kbar were applied with a diamond anvil cell. Absorption of the Pr3+:LiNbO3 crystal is characterized by the strong threshold at about 400 nm, related to the band-to band-transitions and the sharp structure in the visible region attributed to the transitions to 3PJ and 1D2 levels of Pr3+ ion. After the 488 nm excitation the yellow emission related to the 1D2→3HJ transition of Pr3+ have been observed when the 3P0 emission has not been detected. The excitation spectra of the 1D2 luminescence consist of the sharp lines related to the 3H4→3PJ (J=0, 1, 2) transitions and two broad bands peaked at 340 and 400 nm related probably to the bound exciton. The 1D2→3HJ emission shifts with pressure toward the lower energies with the rate of −2.4 cm−1 kbar−1. Additionally, for higher pressures the 1D2 emission is considerably quenched. This is explained as being due to the decrease of the energy of the bound exciton with pressure which results in the higher nonradiative depopulation rate of the 1D2 state. 相似文献