Equal unpleasantness matching of malodorous substances in the community.

5 different odorants, produced through combustion procedures of animal manure, were matched with hydrogen sulfide with regard to unpleasantness by 30 female 20-47 yr olds. Power functions described the unpleasantness matchings for 5 combustion toilets tested. The exponents of the equal sensation functions indicated a relative invariance of the various combustion procedures on the exponent. Different combustion procedures resulted in different levels of odor unpleasantness, but these differences were small from a practical point of view. Results demonstrate the practical applicability of psychophysical methods in environmental health research. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A unified 23Na NMR chemical shift correlation with structural parameters in multicomponent silicate-based glasses

From a large ensemble of 34 silicate-based glasses from the borosilicate, phosphosilicate, and borophosphosilicate systems that comprise either Na as a sole glass-network modifier or when mixed with Ca, we established a good correlation between the ²³Na average isotropic chemical shift () and the average coordination number of Na and the mean Na–O distance. The latter parameters were obtained by atomistic molecular dynamics simulations. We also demonstrated that is essentially independent on the precise network forming (Si, B, P) species but depends primarily on the net molar fraction of Na and Ca, thereby offering a straightforward ²³Na chemical shift prediction from the glass composition alone.