scholarly journals The rate of evaporation of droplets. Evaporation and diffusion coefficients, and vapour pressures of dibutyl phthalate and butyl stearate

The rate of evaporation of drops of dibutyl phthalate and butyl stearate of radius approx. 0.5 mm. has been studied by means of a microbalance over a range of atmospheric pressures down to approx. 0*1 mm. of mercury. Wide departures from Langmuir’s evaporation formula were found to occur at these low pressures, but results are in good accordance with the theory of droplet evaporation advanced by Fuchs which hitherto has not been tested experimentally. This experimental verification of Fuch’s theory for droplets of medium size evaporating at low pressures shows that the theory can be applied to the evaporation of very small drops at atmospheric pressure. The vapour pressures of the above liquids have been measured by Knudsen’s method and the evaporation and diffusion coefficients calculated fro n the experimental data.

The vapour pressures, latent heats of vaporization and fusion and diffusion coefficients of the vapours in air, have been determined at 15 to 40° C, by a combination of Knudsen’s vapour-pressure technique and studies on the rate of evaporation of drops and solid beads, for n -C 16 H 34 , n -C 17 H 36 and n -C 18 H 38 . The rates of evaporation of drops and solid beads agree with the previously published theory, and lead to a value of unity for the evaporation coefficient. A new experimental method is described for determining the self-cooling on evaporation of a drop. The bearing of the results on the size and shape of hydrocarbon molecules is discussed.


1998 ◽  
Vol 63 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Petr Sysel ◽  
Vladimír Hynek ◽  
Milan Šípek

Water transport through and sorption in films of polyimide-polysiloxane block copolymers were studied at 25 °C and atmospheric pressure. The permeability and diffusion coefficients and, to a certain extent, also the sorbed amount were found to depend on the content of the polysiloxane blocks.


2004 ◽  
Vol 03 (01) ◽  
pp. 69-90 ◽  
Author(s):  
BEHZAD HAGHIGHI ◽  
ALIREZA HASSANI DJAVANMARDI ◽  
MOHAMAD MEHDI PAPARI ◽  
MOHSEN NAJAFI

Viscosity and diffusion coefficients for five equimolar binary gas mixtures of SF 6 with O 2, CO 2, CF 4, N 2 and CH 4 gases are determined from the extended principle of corresponding states of viscosity by the inversion technique. The Lennard–Jones 12-6 (LJ 12-6) potential energy function is used as the initial model potential required by the technique. The obtained interaction potential energies from the inversion procedure reproduce viscosity within 1% and diffusion coefficients within 5%.


2008 ◽  
Vol 40 (02) ◽  
pp. 529-547
Author(s):  
Francisco J. Piera ◽  
Ravi R. Mazumdar ◽  
Fabrice M. Guillemin

In this paper we consider reflected diffusions with positive and negative jumps, constrained to lie in the nonnegative orthant of ℝ n . We allow for the drift and diffusion coefficients, as well as for the directions of reflection, to be random fields over time and space. We provide a boundary behavior characterization, generalizing known results in the nonrandom coefficients and constant directions of the reflection case. In particular, the regulator processes are related to semimartingale local times at the boundaries, and they are shown not to charge the times the process expends at the intersection of boundary faces. Using the boundary results, we extend the conditions for product-form distributions in the stationary regime to the case when the drift and diffusion coefficients, as well as the directions of reflection, are random fields over space.


1994 ◽  
Vol 353 ◽  
Author(s):  
Sergey V. Stefanovsky ◽  
Igor A. Ivanov ◽  
Anatolii N. Gulin

AbstractTo immobilize a high sulfate radioactive wastes a system Na2O-A12O3-P2O5-SO3 has been chosen as one where glasses have a relatively low melting points and good chemical durability. Glasses within partial system 44 Na2O, 20 A12O3 (36-x) P2O5 x SO3 have been prepared at 1000 °C. A possibility of assimilation up to 12 mole % of SO3 has been established. The basic properties of sulfate-containing glasses as density, microhardness, thermal expansion coefficient, transformation and deformation temperatures, viscosity, electric resistivity, leach rate of ions and diffusion coefficients of 22Na, 35S, 90Sr and 137Cs have been measured. Glass structure by infrared and EPR spectroscopies has been investigated.


2017 ◽  
Vol 11 ◽  
pp. 283-296
Author(s):  
A. F. Bogatyrev ◽  
O. A. Makeenkova ◽  
V. R. Belalov ◽  
M. A. Kucherenko

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