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Protective coatings and sealants for solar applications

Description: An aging study has been completed which evaluated a number of polymeric materials for potential use as (1) protective coatings for back surfaces of mirrors and (2) solar heliostat edge seals. These investigations were conducted in an artificial weathering chamber that accelerated thermal cycling. The primary mirror failure mode was observed to be silver corrosion resulting from moisture exposure. To increase mirror longevity in current heliostat designs, intimate bonding at all the composite interfaces is essential to minimize moisture pathways to the silvered surface. If any voids or delaminations are present, mirror degradation will eventually occur. Delaminations can also occur as the result of mechanical stresses brought about by mismatches in the various materials coefficients of thermal expansion. If good bonding cannot be achieved or mechanical stresses avoided, then improved moisture barriers must be designed to assure mirror longevity. With good adhesion, a KRATON rubber was found to exhibit superior back surface mirror protection (12 months in environmental chamber with no corrosion). An ultraviolet stabilized butyl rubber appeared to be the best edge seal. All heliostats edge sealed with silicones showed silver corrosion which indicated either poor bonding or moisture permeation.
Date: September 1, 1980
Creator: Wischmann, K. B. & Gonzales, M. H.
Partner: UNT Libraries Government Documents Department

Relationship between air sampling data from glove box work areas and inhalation risk to the worker

Description: A mockup of a plutonium work area was equipped to simulate and monitor aerosol leaks from a glove box into the worker's environment. Dioctyl phthalate was the tracer aerosol used, and aerosol concentration throughout the work area was monitored under several different ventilating conditions. Aerosol concentration in the worker's breathing zone was up to 250 times greater than the concentrations that might be indicated by typical fixed room-air samplers located adjacent to the glove box. The effuct on the magnitude and pattern of aerosol dispersal was evaluated in light of ventilation rate and direction of the ventilating air flow relative to the leak. (auth)
Date: March 1, 1974
Creator: Gonzales, M.; Ettinger, H.J.; Stafford, R.G. & Breckinridge, C.E.
Partner: UNT Libraries Government Documents Department

Aerosol sampling and characterization in the developing US oil-shale industry

Description: Aerosol sampling and characterization studies of workplace air were conducted at four demonstration-scale oil shale facilities located in northwestern Colorado and northeastern Utah. These facilities consisted of an underground mining/aboveground retorting facility, two modified in situ retorting facilities with associated underground mining, and a true in situ retorting facility. Emphasis was placed on study of the retorting phase of operation at these facilities. Aerosol samples were collected on filter media by high volume air samplers, low volume portable sampling pumps with or without cyclone pre-separators, and cascade impactors. Samples were analyzed to determine total and respirable dust concentrations, particle size distributions, free silica content, total benzene or cyclohexane extractables, and selected polynuclear aromatic hydrocarbons. Total and respirable dust were observed to range from very low to very high concentrations, with significant free silica content. Measurable levels of polynuclear aromatic hydrocarbons were also observed at each of the facilities.
Date: January 1, 1981
Creator: Hargis, K.M.; Tillery, M.I.; Gonzales, M. & Garcia, L.L.
Partner: UNT Libraries Government Documents Department

Performance of multiple HEPA filters against plutonium aerosols

Description: Performance of multiple stages of high-efficiency particulate air (HEPA) filters has been verified against plutonium aerosols similar in size characteristics to those challenging the air-cleaning systems of plutonium-processing facilities. An experimental program was conducted to test each filter in systems of three HEPA filters operated in series against /sup 238/PuO/sub 2/ aerosols as high as 3.3 x 10/sup 10/ dis/s . m/sup 3/ in activity concentration and ranging from 0.22 ..mu..m to 1.6 ..mu..m in activity median aerodynamic diameter (amad). Mean penetration (ratio of downstream to upstream concentration) of each of the three filters in series was below 0.0002, but it apparently increased at each successive filter. Penetration vs size measurements showed that maximum penetration of /sup 238/PuO/sub 2/ occurred for sizes between 0.4- and 0.7-..mu..m aerodynamic diameter (D/sub ae/). HEPA filter penetration at half of rated flow differed little from full-flow penetration.
Date: November 1, 1976
Creator: Gonzales, M.; Elder, J. C.; Tillery, M. I. & Ettinger, H. J.
Partner: UNT Libraries Government Documents Department

Comparative inhalation studies with American and Estonian oil shale

Description: This paper presents interim findings on studies comparing the effects of long-term inhalation of quartz, Estonian kukersite, or American Green River shales in rats. No tumors have been observed in the exposed animals. In the studies with Green River shales, the rate of death increased as the animals approached 2 years of exposure. Varying degrees of lung fibrosis has been noted in these animals also. Animals in the kukersite group exhibited only mild changes with some alveolar thickening, and increased macrophages and collagen. Quartz exposed animals suffered severe fibrosis after several months exposure and died after 12 to 15 months.
Date: January 1, 1981
Creator: Holland, L.M.; Vigil, E.A.; Gonzales, M. & Tillery, M.I.
Partner: UNT Libraries Government Documents Department

Test ventilation with smoke, bubbles, and balloons

Description: The behavior of smoke, bubbles, and helium-filled balloons was videotaped to demonstrate the mixing of air in the plutonium chemistry laboratories, a plutonium facility. The air-distribution patterns, as indicated by each method, were compared. Helium-filled balloons proved more useful than bubbles or smoke in the visualization of airflow patterns. The replay of various segments of the videotape proved useful in evaluating the different techniques and in identifying airflow trends responsible for air mixing. 6 refs.
Date: January 1, 1987
Creator: Pickering, P.L.; Cucchiara, A.L.; McAtee, J.L. & Gonzales, M.
Partner: UNT Libraries Government Documents Department