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Table
The experimental and calculated values of the surface area-pore volume ratio Si/Vo, for water-OGS systems
Го, mm calc by (2) Exp
0 07 021 303 70 45
satisfactory agrees with the theoretical S|/Vo value calculated tor a random packing of spheres (with one and the same radius ro»0 07 mm) according to the formula derived m [4]
S, = 3(1-К Го Ф '
Note that Fig 3 shows the dependences of D(t)/D0 on rms displacement of molecules (that is, the horizontal axis of the plot is normalized by the -Jd^ value) recorded at different temperatures T for water-OGSs systems In both cases, the points fit one and the same curve within the limits of experimental error Consequently, a change in the measurement temperature T should not affect the results obtained by estimation of Si/V0 from the short-time dependence of the self-diffusion coefficient, m fact we observed this independence This fact enables us to draw an important conclusion T-he D(t)/Do dependence measured in our experiments for the systems in question indeed, exactly as is required by eq (1), reflect mostly the atfect of geometrical limitations on the diffusion motion of molecules m the pore space
Thus, our experimental study on the time dependence of the rms displacement m a medium with limitations demonstrates the high potentialities of the PFG NMR method in the estimation of geometrical characteristics of a porous medium
REFERENCES
[1 jDvoyashkm, NK, Skirda, VD, and Maklakov, AI, Appl MagnReson, 1991, vol2, no l,p83
[2 ] Maklakov, AI, Fatkullm, RF , and Dvoyashkin, NK,Zi Eksp Teor Fiz, 1992, vol 100,p 901
[3 ] Mitra, P P , Sen, RN , and Schwartz, L M , Phys Rev В Condens Matter, 1993 vol 47, no 14, p 8565
[4 ]Latour, L L , Mitra, P P , Klemberg, R L , and Sotak, С H , J Magn Reson, Ser A, 1993, vol 101, p 342
[5 ]Sen, P N , Schwartz, L M , and Mitra, P P , Magn Reson Imaging, 1994, vol 12, no 2, 227
[6 ]Lykov, A V , Teplomassoobmen (Heat and Mass Transfer), Moscow Energiya, 1978 [7 ]Hurliman, M D , Heimer, К G , Latour, L L , and Sotak, S H, / Magn Reson Ser A 1994, vol 3, p 169
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