calcium aluminates (ca) are the most important hydraulically setting cements used for preparing refractory castables, because they develop high strength at very early ages after placements.  the anhydrous phases of this kind of cements are ca, ca2 and traces of c12a7 and alpha-alumina. the major hydraulic phase in all of the ca cements including ciment fondue is ca. once hydrated, it starts to ...

Infrared predissociation spectroscopy of ion-solvent clusters has allowed us to examine the effects of sequential hydration on the reactivity of cations such as NO, NO2, and protonaled formaldehyde, H2COH, stable gas phase ions which are known to undergo rapid reactions in aqueous solution. Our experiments demonstrate that these ions undergo hydration reactions at critical cluster sizes. The sm...

The thermodynamic and kinetic aspects of hydration reactions of cis-/transplatin were explored. The polarizable continuum model was used for estimation of solvent effects. Using the B3LYP/6-31+G(d) method, the structures were optimized and vibrational frequencies estimated. Interaction energies and activation barriers were determined at the CCSD(T)/6-31++G(d,p) level within the COSMO approach. ...

Calcium aluminates (CA) are the most important hydraulically setting cements used for preparing refractory castables, because they develop high strength at very early ages after placements.  The anhydrous phases of this kind of cements are CA, CA2 and traces of C12A7 and alpha-alumina. The major hydraulic phase in all of the CA cements including ciment fondu...

Solvent additives (cosolvents, osmolytes) modulate biochemical reactions if, during the course of the reaction, there is a change in preferential interactions of solvent components with the reacting system. Preferential interactions can be expressed in terms of preferential binding of the cosolvent or its preferential exclusion (preferential hydration). The driving force is the perturbation by ...

the major hydraulic phase in all the calcium aluminate cements including ciment fondue is ca (caal2o4). once hydrated, it starts to form the hexagonal crystals of cah10 and c2ah8 that depending on the time and temperature of hydration convert to the cubic crystals of c3ah6 and ah3. the nature, sequence, crystallinity and microstructure of hydrated phases of commercial refractory calcium alumina...

Full-quantum mechanical fragment molecular orbital-based molecular dynamics (FMO-MD) simulations were applied to the hydration reaction of formaldehyde in water solution under neutral conditions. Two mechanisms, a concerted and a stepwise one, were considered with respect to the nucleophilic addition and the proton transfer. Preliminary molecular orbital calculations by means of polarized conti...