scholarly journals Thin-source concentration dependent diffusion

1978 ◽  
Author(s):  
G. Eng
2014 ◽  
Vol 6 (1) ◽  
pp. 1024-1031
Author(s):  
R R Yadav ◽  
Gulrana Gulrana ◽  
Dilip Kumar Jaiswal

The present paper has been focused mainly towards understanding of the various parameters affecting the transport of conservative solutes in horizontally semi-infinite porous media. A model is presented for simulating one-dimensional transport of solute considering the porous medium to be homogeneous, isotropic and adsorbing nature under the influence of periodic seepage velocity. Initially the porous domain is not solute free. The solute is initially introduced from a sinusoidal point source. The transport equation is solved analytically by using Laplace Transformation Technique. Alternate as an illustration; solutions for the present problem are illustrated by numerical examples and graphs.


1965 ◽  
Vol 32 (1) ◽  
pp. 125-127 ◽  
Author(s):  
V.E. Viola ◽  
D.J. O'Connell

2014 ◽  
Vol 513-517 ◽  
pp. 7-11
Author(s):  
Cong Cong Zhao ◽  
Xiao Wei Li ◽  
Xi Ming Chen ◽  
Ming Chang

Bias voltage assisted hot filament chemical vapor deposition (HFCVD) was adopted to deposit boron-doped diamond (BDD) film on porous titanium substrate, and diamond composite membrane materials were prepared and characterized by X-ray diffraction method. The influence of carbon concentration, boron source concentration, substrate temperature were discussed respectively on the diamond quality and the transition layer TiC. Results showed that: The concentration of carbon source was related to crystal orientation and the growth rate of diamond. The increase of diamond nucleation density and growth rate prevented the formation of TiC, and improved adhesion between diamond and the substrate; The increasing of boron source concentration promoted the orientation growth of diamond film (111) lattice plane, while reduced the content of TiC; Temperature affected the formation of TiC, and TiC diffraction peaks intensity decreased with the increase of substrate temperature; As the substrate temperature increased, secondary nucleation rate caused cauliflower-like structure which dominated growth mechanism transitting from MCD (Microcrystalline diamond) to the NCD (Nanocrystalline diamond).


1982 ◽  
Vol 99 ◽  
pp. 589-595
Author(s):  
W. T. Sanders ◽  
J. P. Cassinelli ◽  
K. A. van der Hucht

Preliminary results of three X-ray surveys are presented. Out of a sample of 20 stars, X-rays were detected from four Wolf-Rayet stars and two 08f+ stars. The detected stars have about the same mean value as 0 stars for the X-ray to total luminosity ratio, LX/L = 10−7, but exhibit a much larger variation about the mean. The spectral energy distributions are also found to be like that of 0 stars in that they do not exhibit large attenuation of X-rays softer than 1 keV. This indicates that for both the 0 stars and WR stars much of the X-ray emission is coming from hot wisps or shocks in the outer regions of the winds and not from a thin source at the base of the wind. The general spectral shape and flux level place severe restrictions on models that attribute the lack of hydrogen emission lines to extremely high temperatures of the gas in the wind.


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