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Biomedical subjects

D W Underhill

Publications and source records attributed to D W Underhill.

7 recordsLinked to original sources
PubMed1987

Calculation of the performance of activated carbon at high relative humidities.

The Dubinin-Radushkevich potential theory was extended to include a term giving the effect of relative humidity on the uptake of adsorbate. This extended equation permits the adsorptive capacity of the activated charcoal in a respirator cartridge to be estimated for any combination of temperature, relative humidity, and concentration of contaminant. Application of this theory to previously published data of Werner showed a good correlation between theory and experiment. This equation is consistent with the experimental observations that 1) below a certain value, the relative humidity has little effect on the uptake of adsorbate, and 2) the effect of relative humidity, if observed, is more severe for lower than for higher concentrations of contaminant.

Adsorption↗
PubMed1979

A critique of the U.S. standard for industrial exposure to sodium hydroxide aerosols.

Published studies of the toxicity of sodium hydroxide aerosols are few. These studies were generally marred by inadequate characterization of particle size and chemical compositon and of the ambient humidity. Because NaOH aerosols can readily undergo reaction with carbon dioxide to form sodium carbonate, a much less alkaline (and less hygroscopic) compound, these shortcomings may warrant a reconsideration of the NaOH standard and the consideration of a Na2CO3 standard.

Aerosols↗
PubMed1978

Respiratory response of guinea pigs to ozone alone and with sulfur dioxide.

This study was designed to utilize our guinea pig bioassay method for irritant response to address the question of whether or not ozone and sulfur dioxide appeared to react to form sulfuric acid in the respiratory tract. Animals were exposed to 0.2, 0.4, and 0.8 ppm of each gas alone and to the combination at concentrations of 0.4 and 0.8 ppm. In these experiments sulfur dioxide alone produced no statistically significant alterations in respiration. All concentrations of ozone produced an increase in respiratory frequency. At the two higher concentrations the increase in frequency was accompanied by a decrease in compliance. The response to the combinations was the same as the response to those levels of ozone alone. No sulfuric acid was detected in the chamber atmosphere. The biological data suggest that none was formed in the lung.

Animals↗