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Biomedical subjects

D A Fraser

Publications and source records attributed to D A Fraser.

13 recordsLinked to original sources
PubMed1980

Passive dosimetry using detector tubes.

Detector tubes for toluene were cut to produce a nominal 0.5 cm orifice above the indicator material, and exposed to known vapor concentrations. The time needed to reach a pre-determined stain length by simple diffusion was measured. Calibration charts were prepared for time versus concentration for a 1 mm stain, as well as for various stain lengths. Tests were performed to determine the effect of increasing the orifice length and of diffusion through the glass wool plug. Each of these parameters resulted in less reliable concentration measurements than tubes of relatively shorter orifice length having no glass wool plug. Diffusion theory was used to develop theoretical calibration charts for comparison with experimental results, with the former underestimating necessary for appearance of the experimentally observed stains. The use of detector tubes having an orifice length of 0.5 cm as passive dosimeters is shown to be highly feasible based on experimental results.

Equipment and Supplies↗
PubMed1977

Air sampling and analysis in a rubber vulcanization area.

Results of sampling and analysis of air in a rubber vulcanization area are described. Organic compounds were collected on activated charcoal, desorbed with carbon disulfide and analyzed by gas chromatography. Several previously identified substances were quantitated, including styrene, toluene, ethylbenzene, and several oligomers of 1,3-butadiene. Concentrations ranged from 0.007 to 1.1 ppm.

Air Pollutants↗
PubMed1976

A model for deposition of fibers in the human respiratory system.

A mathematical model for estimating lung deposition of fibers is described. It is based on the aerodynamic behavior of thin straight rods. Predicted deposition values for rods of various equivalent aerodynamic diameters and lengths, for each of three tidal volumes and for each of three respiratory system compartments are reported.

Bronchi↗
PubMed1976

Health aspects of the curing of synthetic rubbers.

A commonly used tread rubber formulation was cured in the laboratory under conditions simulating vulcanization in the Bag-O-Matic press. Volatile emissions were collected on charcoal and analyzed by combined GC-mass spectrometry. The compounds identified were either contaminants present in the raw material or reaction products. Some of these compounds were also identified in charcoal tube samples collected in the atmosphere of the industrial operations. Estimates based on the loss of weight of rubber during curing were used to predict airborne concentrations and compared to the concentrations actually found. The literature of the toxicity of raw materials and effluents was reviewed, and no acute or chronic toxicological effects would be anticipated. Information concerning potential carcinogenicity was not available and could not be evaluated.

Air Pollutants, Occupational↗