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.