Thermodynamic Calculation of a Heat of First-Order Phase Transitions

A transition heat is the most important characteristics of first-order phase transitions. Black was first who discovered in 1762 that in the transfer of water to vapor, some quantity of heat is absorbed, which he termed the latent evaporation heat.

In spite of more than the two-hundred-year period of the heat transfer concept existence there are no analytical expressions relating the transition heat with other parameters of phase transitions.

For example, the fundamental "Physics Encyclopedia", articles devoted to the transition heat, evaporation heat, and so on, comprises no formulae but only tables of experimental data. One can also mention monographs which have no relationships except for the conventional definition of the transition heat λ=TΔS.

PDF LINK

Biogeochemical Cycling of Nutrients and Thermodynamic Aspects

The term “biogeochemical cycles” is used in order to describe the transfer and transformation of matter and energy between the biosphere and the other active reservoirs of Earth namely the atmosphere, hydrosphere, and lithosphere.

During the functioning of a biogeochemical cycle, a series of molecular species which are essential for supporting life on the planet, also referred to as nutrients, are being constantly transported and chemically transformed. The main chemical elements making up the basic nutrients circulating within a specific biogeochemical cycle and which are involved in the structuring of complex bio-polymers (e.g. proteins, DNA, RNA, etc.) are C, N, S, P, and O.

A biogeochemical cycle is activated via coupling of the biosphere to nutrient fluxes supplied by specific sites or active centers on Earth (e.g. volcanoes and hydrothermal fields). Such sites/centers act as a constant source of matter (e.g. volatile chemical species) and/ or energy on the Earth surface, either on a regional or a global scale, which can be used by different living forms.