Green roofs can be an effective and appealing way to increase the energy efficiency of buildings by providing active insulation. As plants in the green roof transpire, there is a reduction in heat flux that is conducted through the green roof. The R-value, or thermal resistance, of a green roof is an effective measurement of thermal performance because it can be easily included in building energy calculations applicable to many different buildings and situations. The purpose of this study was to determine if an increase in ambient temperature would cause an increase in the R-value of green roofs. Test trays containing green roof materials were tested in a low speed wind tunnel equipped to determine the R-value of the trays. Three different plant species were tested in this study, ryegrass (Lolium perenne), sedum (Sedum hispanicum), and vinca (Vinca minor). For each test in this study the relative humidity was maintained at 45% and the soil was saturated with water. The trays were tested at four different ambient temperatures, ranging from room temperature to 120ºF. The resulting R-values for sedum ranged from 1.37 to 3.28 ft²h°F/BTU, for ryegrass the R-values ranged from 2.15 to 3.62 ft²h°F/BTU, and for vinca the R-values ranged from 3.15 to 5.19 ft²h°F/BTU. The average R-value for all the tests in this study was 3.20 ft²h°F/BTU. The results showed an increase in R-value with increasing temperature. Applying an ANOVA analysis to the data, the relationship between temperature and R-value for all three plant species was found to be statistically significant.

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M.S.

Lethal toxicity values (96 h LC50; mg Cd/L) for the test species were similar: Lepomis cyanellus, 11.52; Notropis lutrensis, 6.62; Pimephales promelus, 3.58. However the effects of cadmium concentration and exposure time on temperature tolerance varied between species. Neither cadmium concentration nor exposure time had a significant effect on the CTM of green sunfish. Both cadmium concentration and exposure time had a significant effect on the CTMs of red shiners and fathead minnows. By day 10 mean CTMs were 2.3 t- 4.5 C (red shiners) and 4.2 to 5.7 C (fathead minnows) lower than control CTM. These results suggest a potential problem in cadmium contaminated systems for high environmental temperatures to stress or kill fish.

Temperature, one of the most influential factors controlling the growth and distribution of plants, was measured during a three month summer period within several stands of vegetation. The stands represented four distinct plant communities: sagebrush-grass, mountain brush, aspen, and conifer. Measurements were obtained by a sucrose inversion method which gave exponential average or effective mean temperature (eT) values. Registerants, small glass vials filled with a sucrose-buffer solution, were placed in the air 10 decimeters above the ground level and in the soil 1, 5, and 10 decimeters below the ground level. The sites were carefully described with respect to plant cover and composition, soil profile, soil moisture, precipitation, elevation, aspect, and slope. Each site and plant community varied with respect to some of these factors. Several prominent relationships between the air and soil temperatures and various site factors were encountered. The sagebrush-grass and mountain brush sites had significantly higher temperatures than the aspen and conifer sites. Air and soil temperatures varied inversely with elevation. Soil temperatures varied inversely with soil depth and the variation was statistically significant. Soil temperatures at the one decimeter depth in adjacent sites were nearly 2° C higher in the site with a sparse shrub cover than in the site with a very dense shrub cover. On adjacent sites with opposite exposures the south exposure had soil temperatures which were nearly 6° C higher than the north exposure. Moist sites had lower temperatures than dry sites. Sites with 2 inches of litter and duff had cooler soil temperatures than sites with only 1 inch. Temperature differences between plant communities were measured with the sucrose inversion method even though the various site factors also had their effect upon the temperatures. It was not the intent of this paper to interpret interactions of the various site factors with temperature. It is concluded that the sucrose inversion method of temperature measurement is an easy to use, inexpensive, reliable method for use in ecological studies.

The effects of sublethal copper on metabolism were in vestigated in bluegill (Lepomis macrochirus) by measuring whole body oxygen consumption in fish exposed to sublethal copper alone and in conjunction with a temperature increase. In vitro oxygen consumptions of liver, brain, and gill were also measured under these two conditions, as was the accumulation of copper in these tissues. In addition, the concentration of copper in bile was measured. Copper was found to decrease whole body oxygen consumption in animals exposed to copper alone, although the oxygen consumptions of tissues were not significantly altered. This indicates that copper is acting to decrease VO₂ at a higher level of integration than the individual tissues. In animals subjected to an increase in temperature as well as sublethal copper, oxygen consumption was higher than controls five days after the temperature was increased, indicating a delay in temperature acclimation. This increase was reflected in higher in vitro oxygen consumption in the liver and gill indicating that sublethal copper delays temperature acclimation by acting directly on the tissues. Tissue copper accumulation was seen first in the gills followed by accumulation in the liver. Copper was not found to accumulate in the brain. Increased copper levels were found in the bile at all tested exposure times. A discussion of the ecological implications of these findings is included. / M. S.

Pure cultures of Saprolegnia ferax (Gruith) Thuret, Achlya americana Humphrey, and two isolates of Saprolegnia parasitica Coker were grown in a chemically defined medium under controlled conditions of temperature and illumination. Light inhibited growth and oogonium formation rates in S. ferax and A. americana. Light inhibited zoospore germination rates in A. americana and the growth rate of S. parasitica isolate 2-27-59; S. parasitica isolate 6-28-60 was indifferent to light. Neither isolate of S. parasitica formed sexual structures during the experiments. Differences in light reactions and growth rates of these two isolates indicated physiological strain differences. Photoreactivation was demonstrated in S. ferax and both isolates of S. parasitica. Evidence was shown that light caused production of toxic substances in the medium which caused inhibition of growth and sporulation. The blue peroxychromic test for hydrogen peroxide in the medium was negative but apparent catalase activity was demonstrated. Using a simple medium consisting of glucose, soluble starch and yeast extract, white light stimulated vegetative growth in S. ferax and A. americana. A quantitative distribution pattern of oogonium formation was shown. / Ph. D.

For heat transfer through building insulations such as fiberglass, radiation and conduction are important modes of heat transfer. Moreover, materials like fiberglass scatter radiation in a highly anisotropic manner. The equations for heat transfer by simultaneous conduction and radiation are a coupled pair, one of which is of the nonlinear integrodifferential type. Exact solution for transient heat transfer in this case is not available, and the approximate solution available is the two-flux model. The two-flux model does not give good results for transient, combined mode heat transfer, through an absorbing, emitting, and anisotropically scattering medium. In this thesis a higher order approximate solution has been developed. It is found that this model gives appreciably better results than the two-flux model. / Master of Science