Showing papers by "Naval Surface Warfare Center published in 1982"

Linear solvation energy relationships. Part 9.—Correlations of gas/liquid partition coefficients with the solvatochromic parameters, π*, α and β

Abstract: When referenced to an alkane solute of similar molecular volume, i.e. log (Ksolute/Kalkane), gas/liquid partition coefficients for nitromethane, methylethylketone, dioxan, toluene and ethanol solutes are well correlated by the solvatochromic parameters, π*, δ, α and β. For nitromethane and dioxan solutes the partition coefficients depend only on the dipolarity/polarizability parameters (π*, δ). For methylethylketone, there is also a measurable dependence on hydrogen-bond donor acidity (α) of protic solvents. For ethanol in aliphatic non-hydrogen-bond donor solvents the dominant effects are solvent dipolarity/polarizability and solvent hydrogen-bond acceptor basicity (β). For toluene solute there appears to be a negative or desolvation effect in protic solvents which is attributed to a ‘hydroxyphobic effect’ of weakly basic solutes in alcohol solvents.

Spin‐echo NMR study of the atomic site environments in the Fe67Co18B14Si1 metallic glass

Abstract: In order to investigate the near neighbor atomic environment and, consequently, the relationship of such environments to the observed magnetoelastic properties, a spin‐echo NMR study of the hyperfine field distributions in Metglas 2605 CO (Fe67Co18B14Si1) for various magnetic annealing treatments has been undertaken. Here, initial spectra for the 11B metalloid and 59Co transition metal nuclei, obtained at 4.2 °K and zero magnetic field, are presented along with supplementary magnetization and x‐ray diffraction measurements. Upon annealing, a bcc α‐Fe phase precipitates first, leaving a residual amorphous phase of lower Fe content. The appearance of such crystalline regions is accompanied by a strong reduction in the magnetomechanical coupling coefficient.