Some approximations of the temperature integral through integration over small temperature intervals

1985 ◽  
Vol 91 ◽  
pp. 383-386 ◽  
Author(s):  
E. Urbanovici ◽  
E. Segal
Keyword(s):  
Temperature Integral ◽  
Small Temperature

scholarly journals Effects of Ambient Pressure on the Instability of a Liquid Boiling Explosively at the Superheat Limit

1986 ◽  
Vol 108 (2) ◽  
pp. 418-424 ◽  
Author(s):  
D. Frost ◽  
B. Sturtevant
Keyword(s):  
Atmospheric Pressure ◽  
Bubble Growth ◽  
Absolute Stability ◽  
Pressure Field ◽  
Ambient Pressure ◽  
Small Temperature ◽  
Instability Theory ◽  
Two Stages ◽  
Single Droplets ◽  
Superheat Limit

The effect of ambient pressure on the intrinsic instability of rapid vaporization in single droplets boiling explosively at the limit of superheat has been studied experimentally and theoretically. The instability that distorts the evaporating interface and substantially enhances the mass flux at atmospheric pressure is suppressed at high pressure. The radiated pressure field is two orders of magnitude smaller from stabilized bubbles than from unstable. At intermediate pressures bubble growth occurs in two stages, first stable, then unstable. The Landau–Darrieus instability theory predicts absolute stability at atmospheric pressure for a spherical bubble, whereas the theory for planar interfaces yields results in general agreement with observation. The sensitivity of the instability to temperature suggests that small temperature nonuniformities may be responsible for quantitative departures of the behavior from predictions.

scholarly journals ANALYSIS OF ANNUAL VARIATIONS IN GROUND TEMPERATURE AT AN OTTAWA SITE

1964 ◽  
Vol 1 (2) ◽  
pp. 146-157 ◽  
Author(s):  
L. W. Gold
Keyword(s):  
Gradual Increase ◽  
Ground Temperature ◽  
Small Temperature ◽  
Temperature Changes ◽  
Annual Variations ◽  
Periodic Fluctuations ◽  
A Site

Observations over a 5-year period at a site at Ottawa showed that the ground temperature had significant Fourier components with period [Formula: see text]and 2 years. The average annual ground temperature and amplitudes of the Fourier components of period 1 year and [Formula: see text] year underwent non-periodic fluctuations of almost 1 C degree at a depth of 10 cm. The amplitude of this fluctuation decreased with depth, and its maximum occurred later in time. There was evidence of a gradual increase in average annual ground temperature amounting to about 0.2 C degree over the 5-year period at the 610-cm depth. The significance of such small temperature changes in areas where the ground temperature is close to 0 °C is pointed out.

Studies With Transient Compact Models of Packages and Heat Sinks

2003 ◽  
Author(s):  
M. Rencz ◽  
V. Sze´kely ◽  
B. Courtois
Keyword(s):  
Linear Models ◽  
Heat Sinks ◽  
Simulation Experiments ◽  
Small Temperature ◽  
Thermal Models ◽  
Linear And Nonlinear ◽  
Compact Models ◽  
Board Level

This paper deals with the application of dynamic compact thermal models of packages. First an algorithm and a methodology is presented, that was developed for the inclusion of compact electrical RC thermal models of packages into field solvers, to enable fast board level simulation with compact models of packages. Application examples demonstrate the advantages of the method. In the second part of the paper a method is presented for the generation of nonlinear compact models. Simulation experiments comparing linear and nonlinear compact models show that for small temperature excursions the use of linear models is acceptable, but in case of larger than 80°C temperature increases the use of linear models results in an about 20–30% regular error for the usual package structures.

X-ray reflectivity study of the influence of temperature fluctuations on the density profile of thin liquid films

2004 ◽  
Vol 219 (4) ◽  
Author(s):  
Robert Fendt ◽  
Michael Sprung ◽  
Christian Gutt ◽  
Oliver Hermann Seeck ◽  
Metin Tolan
Keyword(s):  
Density Profile ◽  
Temperature Fluctuations ◽  
Liquid Films ◽  
Electron Density Profile ◽  
Thin Liquid Films ◽  
Inversion Method ◽  
Layered System ◽  
Small Temperature ◽  
Influence Of Temperature ◽  
X Ray

AbstractWe report on X-ray reflectivity experiments of thin liquid heptane films. The films were examined using X-ray reflectivity and modelled both as a layered system using the Parratt algorithm and using a ´phase guessing´ inversion method. Our results combined with simulations of films of shrinking thickness show that small temperature instabilities during the investigation can cause artifacts in the electron density profile. These can easily be mistaken for density os cillations near the interface as might be expected for liquid molecules near a hard wall.

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