Engineering topics

Lasaga, A. C.

Publications and source records attributed to Lasaga, A. C..

3 records

NASA NTRS1993

Theoretical reaction pathways for the formation of (Si(OH)5)(1-) and the deprotonation of orthosilicic acid in basic solution

The stability of (Si(OH)5)(1-) is predicted by means of molecular orbital calculations. Si is predicted to be as stable in basic aqueous solutions as hydrated (/OH/3SiO)(1-) and more stable than Si(OH)4 + (OH)(1-). Vibrational analysis of (Si(OH)5)(1-) predicts Raman and IR spectra that are not compatible with the presence of Si in some silicate glasses under ambient temperature compression.

Kubicki, J. D.↗

NASA NTRS1977

Slowly cooled microgabbros 15555 and 15065

An experimental study involving equilibration of Apollo 15 samples 15555 and 15065 in high-purity iron capsules is described. Comparison of mineral zoning trends with the experimental sequence suggests that the early crystallizing phases in the rock maintained surface equilibrium with the liquid. Olivine and pyroxene chemistry indicates that 15555 cooled slightly more rapidly than 15065, which cooled at approximately 0.2-0.3 C/day. It is suggested that 15065 and 15555 represent liquid compositions, and that these liquids appear to have been fractionated during ascent through the crust (15065), or to have been derived from an olivine-pyroxene source (15555) with Fe/(Fe + Mg) approximately equal to 0.73 at a depth between 150-200 km.

Walker, D.↗

NASA NTRS1971

Primordial oil slick

Methane atmosphere polymerization by solar UV to form primordial oil slick, discussing importance to life development

Dwyer, M. J.↗