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The nonexchange sorption of diverse electrolytes by an MK-40 sulfonic cation-exchange membrane has been studied by conductometry without separating solution and membrane phases. The data of sorption experiments performed within the framework of the two-phase microheterogeneous model of an ion-exchange material have been used to find the Donnan constant for the MK-40 membrane in solutions of electrolytes, namely, HCl, NaOH, NaCl, MgCl2, CaCl2, and BaCl2. The concentration of an electrolyte sorbed by the membrane has been determined as depending on the nature and concentration of an equilibrium solution. Factors that have the most significant effect on the concentration of a sorbed electrolyte and the Donnan constant, such as the specific moisture capacity of the membrane and the nature and charge of counter- and coions, have been studied. The volume fractions of the gel and equilibrium solution phases have been determined by two methods, i.e., from the experimental data on the membrane specific conductivity in solutions of different natures and concentrations and from the data on the nonexchange sorption calculated within the microheterogeneous model of the membrane structure. It has been shown that the Donnan constant may be calculated for the MK-40 membrane in the salt solutions by a simplified method from the data on the sorption of an electrolyte of only one concentration, provided that the volume fractions of the conducting phases in the membrane are known.

An analysis of information on the groundwater dynamics, frequency of fire events, and postfire progressive-age stages of vegetation in the swamp-forest ecosystems of the southern taiga and forest-steppe zone of the West Siberian Plain has shown that fire events are a permanent factor that controls the scales and dynamics of the forest and swamp formation processes under these specific conditions in the modern era. The greatest influence on the dynamics of ecosystems is exerted by the frequency of fires. The scope and depth of the transformation of swamp ecosystems affected by the pyrogenic factor are due to their environmental regimes and have their own properties in different landscapes.