In order to investigate the effect of zeolite structure on the selectivity for products, computational analysis of molecular dimensions and diffusion parameters of DEC and DEE within Cuβ and CuY catalysts zeolite framework has been performed using molecular mechanics and quantum mechanics methods.
Computational analysis of molecular dimensions and diffusion parameters of the various mono- and diisopropyl and tert-butylbiphenyl isomers within H-MOR and H-BEA zeolite framework has been performed using molecular mechanics and quantum mechanics methods.
The diffusion tensor, scalar diffusion parameters (Axial Diffusivity – AD, Radial Diffusivity – RD, and FA) were calculated by dtifit (FSL).
Accurate predicting carbon dioxide molecular diffusion coefficient is a key parameter during carbon dioxide injection into oil reservoirs.
The DWI imaging was calculated by at two-segment monoexponential algorithm as shown in IVIM equation (1), where D and D∗ are the diffusion parameters related to molecular diffusion and to the perfusion-related diffusion, respectively, S/ S0 is the normalized signal attenuation, and f is the perfusion fraction.
This paper quantifies the third structural parameter (Cm), related to molecular diffusion that arises when a multicomponent gas mixture is introduced into the pore network of a sorbent pellet.
This allows the determination of several different parameters, namely: D, the true molecular diffusion coefficient; D*, the perfusion-related fast diffusion coefficient, which correlates with blood flow; and f, the perfusion fraction, which is linked to the blood volume within tissue [18, 27, 28, 29].
One pilot study demonstrated the usefulness of using IVIM DW imaging with ten b factors to determine the difference of pure molecular-based (D) and perfusion-related (D*, f) diffusion parameters, between patients with cirrhosis and patients without liver fibrosis [ 21].
These models depend on several parameters such as kinetic constants or molecular diffusion constants which are in many cases not accessible to experimental determination.
They concluded by application of the bi-exponential model that the molecular diffusion coefficient D slow and microperfusion fraction f are useful parameters for the characterisation of hepatic lesions.
