Showing papers by "Anthony L. Andrady published in 1999"
TL;DR: The UV radiation environment of Mars with respect to biological systems is examined and appropriate measures to address the problem of the Martian UV environment for future long term human exploration and settlement strategies are considered.
28 citations
TL;DR: Xe NMR spectroscopy was used to study the free-volume changes associated with cross-linking of linear polymers and extensive chain branching in dendritic tree molecules and the change in chemical shift of the xenon was found to correlate well with the reciprocal of the average molecular weight between cross-links of the end-linked networks.
Abstract: 129Xe NMR spectroscopy was used to study the free-volume changes associated with cross-linking of linear polymers and extensive chain branching in dendritic tree molecules. Qualitative changes in the free volume in model networks of poly(oxypropylene) and in starburst dendrimers of poly(amidoamine) were studied as a function of the cross-link density and the generation, respectively. Consistent with the present understanding of these end-linked networks, the change in chemical shift of the xenon was found to correlate well with the reciprocal of the average molecular weight between cross-links of the end-linked networks. With dendrimers, the chemical shift of xenon varied linearly with the generation number. A modified form of the chain-end free volume theory applicable to dendritic molecules was used to interpret the data.
25 citations
TL;DR: In this article, the increase in yellowness index of mechanical pulp (newsprint) paper on exposure to monochromatic radiation at several discrete wavelengths in the region of 260 to 600 nm was studied.
17 citations
TL;DR: In this paper, a respirometer was used to titrimetrically determine the kinetics of gas evolution and the rate of biodegradation was quantified by an empirical rate coefficient.
Abstract: Aerobic mineralization of several different paperboard materials under laboratory-exposure conditions was studied. A novel respirometer was used to titrimetrically determine the kinetics of gas evolution and the rate of biodegradation was quantified by an empirical rate coefficient k. Various bleached paperboard materials studied showed about the same rate (k = 0.14–0.16 days−1) and a 50–58 weight percent conversion of substrate carbon into carbon dioxide under the conditions used in the study. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1773–1779, 1999
4 citations