Program LVPM (Laminated Vuggy Porous Media) has as its main
computational engine TPM, the Transmission Probability Method
discussed in the previous section of this site.

By its very nature, LVPM describes two porous media, Material1 and
Material2. If the user selects the mode "HET" from the OUTPUTS pane,
LVPM models two independent materials with no laminae. This can be
very handy for examining the OUTPUT differences caused by changing a
single INPUT variable. In this mode, the OUTPUTS labeled "classic"
refer to application of standard linear mixing rules applied to the
vug and rock neutron cross-sections and gamma attenuation coefficients
and "heterogeneous" means that the new mixing rules for finite pore
sizes are used. The OUTPUTS are for Material 1 OR Material 2.

However, if the user selects the mode "PARA" or "PERP", LVPM describes
two alternating laminated vuggy porous media oriented parallel or
perpendicular to a standard neutron/gamma transmission direction; bed
thicknesses apply. In these modes, the OUTPUTS labeled "Classic" refer
to the use of standard mixing rules with bed thickness weighting
applied to the macroscopic neutron absorption and scattering
cross-sections, bulk densities, and gamma linear attenuation
coefficients. In these modes, the OUTPUTS labeled "Heterogeneous”
refer to use of the new mixing rules applied to the cross sections and
attenuation coefficients for two laminated materials with separate/
finite pore sizes. The OUTPUTS for these modes depend on the INPUTS for
Material1 AND Material2.