Self-averaging absence

An immediate consequence of this is that Rx approaches a constant as AT —> oo indicating complete absence of self-averaging at the critical point in a random system. 

If the denominator in equation 12 is less than or equal to zero, the mixture has gelled. In this case, the weight average molecular weight is infinite. In the absence of the self-condensation reaction - 0), the gel point is given by ... 

Pulsed field gradient methods may be used in combination with a spin-echo pulse sequence to measure average molecular displacements in a time In liquids, PFG methods can therefore be used to measure self-diffusion coefficients (i.e. the rate of diffusion due to Brownian motion in the absence of a concentration gradient). In porous media, there is the possibility of obtaining information about the pore geometry because the pore boundaries will influence molecular transport. PFG techniques can measure restricted diffusion and thus provide valuable information on pore sizes in the range 5-100 (im. 

In the absence of the colloidal nuclei the monomer level in the solution dropped only from 350 to 320 in 2 hr, indicating only minor self-nucleation. The equilibrium solubility of silica in the system was about 100 ppm. so the average supersaturation was about 200 ppm or three-fold saturation. 

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