retardation factor

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retardation factor (Rf)

(chromatography) the distance travelled by a separated component over the distance travelled by the solvent front. Under specific conditions, the Rf is characteristic of a given component and can be used to identify it.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
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Bivariate correlation analyses of residual change scores with change in the ITAQ over average hospital stays of 51 days (Table 3) showed significant inverse relationships with the residual total HAMD-17 change score (r=-0.36, P<0.001), the residual suicide factor (r=-0.24; P =0.005) and the residual psycho-motor retardation factor (r=-0.32, P < 0.001).
The markers of each the bio-active constituents were visualized and recorded using UV lamp (wavelength ([lambda]) of 254 nm and 365 nm) and the retardation factor, [R.sub.f] of desirable constituent (rotenone) was calculated and shown in Table 2.
This work shows that retardation factor dependency on frequency can be reduced and the pass-band of system can be extended by using internal shields.
where [j.sub.A] is the rate of TMPD-MIB mass transfer per unit area (mg [m.sup.-2] [h.sup.-1]), [D.sub.A] is the diffusion coefficient of TMPD-MIB ([m.sup.2] [h.sup.-1]), [c.sub.A] is the concentration of TMPD-MIB (mg [m.sup.-3]), [R.sub.A] is a kinetic retardation factor that accounts for the transport delay of TMPD-MIB through the latex particles, and z is the space coordinate measured normal to the section (m).
in which c is concentration of solute, t is time, v is pore-water velocity, x is linear distance, K is coefficient of hydrodynamic dispersion, and R is retardation factor.
where [R.sub.f] is the retardation factor in the matrix due to the sorption, defined by:
Using the principles of the matrix algebra and iterations we can find values of the retardation factor [k.sub.R] and frequency f [7]:
We compare the behaviour of the EC of the leachate, representing that of bulk solution, and of the individual ions in terms of the parameters of the convective--diffusion equation (CDE), the retardation factor (R), and the coefficient of hydrodynamic dispersion (K).
Considering the set at zero determinant, we can find values of the retardation factor [k.sub.R] and frequency f [2]:
(1986) and Sudicky (1986) noticed growing retardation factor of reactive solutes in time in a large-scale field test at Borden, Canada.