Free protons Freezing

With temperature, density and Ye as free parameters, many choices of initial NSE compositions may clearly be made, involving a dominance of light or heavy nuclides, as illustrated in Fig. 24. However, in view of its relevance to the supernova models, an initial NSE at temperatures of the order of 1010 K is generally considered. It favours the recombination of essentially all the available protons into a-particles (the region noted NSE n,o in Fig. 24). The evolution of this initial composition to the stage of charged-particle induced reaction freeze-out has been analyzed in detail by [60], and we just summarize here some of its most important features that are of relevance to a possible subsequent r-process ... 

The confinement of water in nanometer-size pores between the walls of the polymer material affects the structure of water. The observed freezing-point suppression [49,50] and reduced dielectric constant of water [115-117], are macroscopic manifestations of this effect. The interfacial area between polymer and water provides a complex environment for proton transport. The complications for the theoretical description are caused by the flexibiHty of the sidechains, their random distributions and their partial penetration into the bulk of water-filled pores. The charged polymer sidechains contribute elastic ( entropic ) and electrostatic terms to the free energy [54,55]. Distribution and mobilities of protons depend strongly on the resulting sidechain-water interactions [54,56,118]. 

In Fig. 10, the fractions of crystalline PVA with respect to the total amotmt of PVA in the crystalline and swollen amorphous phases, obtained by X-ray powder diffraction analysis,/c(XR) [57], are reported as a function of the number of freeze-thaw cycles for the as-formed PVA hydrogels. They are compared with the fractions of crystalline PVA with respect to the total amount of PVA in hydrogels, as determined by DSC,/c(DSC) [42, 57], and the fractions of rigid protons calculated from free induction decay experiments, /c(NMR) [56, 57]. In all cases, the... 

In the case of contact of hydrated silica surface with air (water vapor), the structure of adsorbed water is determined not only by the adsorbent surface (i.e., phase boundary of silica/water) but also by the phase boundary of water/air. Appearance of these phase boundaries leads to reduction of the free energy of the interfacial water accompanied by lowering of its freezing temperature. The information on a structure of the adsorption complexes at a surface of oxide adsorbents can be obtained from temperature dependences of chemical shift of protons of interfacial water molecules. It is necessary to take into account that 5h is defined by strength of the hydrogen bonds between water molecule and active surface sites and depends on the amounts of hydrogen bonds per water molecule. 

After the weak freeze-out, the haryonic matter part essentially consists of free neutrons and protons interacting with each other. Deuterium is constantly formed via neutron captures on... 

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