A structure based model for diffusion in glass and the determination of diffusion constants in silica

1990 ◽  
Vol 124 (2-3) ◽  
pp. 174-180 ◽  
Author(s):  
D.K. McElfresh ◽  
D.G. Howitt
Keyword(s):  
Diffusion Constants

scholarly journals A METHOD FOR THE DETERMINATION OF DIFFUSION CONSTANTS AND THE CALCULATION OF THE RADIUS AND WEIGHT OF THE HEMOGLOBIN MOLECULE

1929 ◽  
Vol 12 (4) ◽  
pp. 543-554 ◽  
Author(s):  
John H. Northrop ◽  
M. L. Anson
Keyword(s):  
Molecular Weight ◽  
Carbon Monoxide ◽  
Diffusion Coefficient ◽  
Porous Membrane ◽  
Diffusion Constants ◽  
Einstein's Equation ◽  
Hemoglobin Molecule

A method is described for determining the diffusion coefficient of solutes by determining the rate of passage of the solute through a thin porous membrane between two solutions of different concentration. The method has been used to determine the diffusion coefficient of carbon monoxide hemoglobin. This was found to be 0.0420 ± 0.0005 cm.2 per day at 5°C. The molecular weight of carbon monoxide hemoglobin calculated by means of Einstein's equation from this quantity is 68,600 ± 1,000.

scholarly journals New Method for the Determination of Diffusion Constants from Partially Narrowed Nmr Lines

1980 ◽  
Vol 3 ◽  
Author(s):  
D. Wolf
Keyword(s):  
Relaxation Time ◽  
Free Induction Decay ◽  
Weighted Sum ◽  
Molecular Motions ◽  
Rigid Lattice ◽  
Background Contribution ◽  
Intermediate Temperature Range ◽  
Diffusion Constants ◽  
Free Induction

ABSTRACTThe effect of atomic and molecular motions on the NMR free-induction decay (FID) and lineshape is investigated theoretically in the intermediate temperature range in which the NMR line is only partially narrowed. It is shown that the FID may be decomposed into the weighted sum of a rigid-lattice (background) contribution and an exponentially decaying part containing all the information on the diffusive or reorientational motions in the crystal in terms of the spin-spin relaxation time T2.

A Simple Method for the Determination of Diffusion Constants

Science ◽  
1950 ◽  
Vol 112 (2921) ◽  
pp. 757-758 ◽  
Author(s):  
L. A. Walker
Keyword(s):  
Simple Method ◽  
Diffusion Constants

A Simple Diffusion Cell for the Determination of Absolute Diffusion Constants using Radioactive Tracers

1971 ◽  
Vol 49 (9) ◽  
pp. 1575-1578 ◽  
Author(s):  
Willy Dyck
Keyword(s):  
Diffusion Coefficient ◽  
Bulk Diffusion ◽  
Ion Concentration ◽  
Detectable Effect ◽  
Diffusion Cell ◽  
Simple Diffusion ◽  
Hydrogen Ion Concentration ◽  
Self Diffusion ◽  
Diffusion Constants

Using microscope slides for the diffusion grating, a glass diffusion cell was constructed which permitted the determination of absolute diffusion constants of γ-ray emitting elements in aqueous solutions.The cell was tested at 25 °C with 110Ag as tracer and gave a bulk-diffusion coefficient of 1.64 × 10 −5 cm2/s and a self-diffusion coefficient of 1.48 × 10−5 cm2/s using 0.01 M AgNO3.The hydrogen ion concentration had no detectable effect on the diffusion coefficient of AgNO3 in the pH range −0.48 to 7.5. The presence of Na or Fe(III) ions, or sucrose molecules at moderate concentrations (> 0.1 M) resulted in a marked decrease in the diffusion coefficient.

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