Because differences often exist between species in their tolerances to environmental conditions, locations characterized by extreme parameter values (i.e., high temperature, low DO, high turbidity) may provide refuges from predation or competition by altering the outcome of inter-species interactions. This thesis examined the effects and relative importance of water temperature, dissolved oxygen (DO) and turbidity on habitat use by fish species and resulting changes in community composition. The effects of abiotic factors on predator-prey interactions were tested using field surveys, laboratory experiments, field experiments and computer modeling. Field surveys were conducted in Blind Channel, Delta Marsh, Manitoba, and on Lake Winnipeg, Manitoba, to determine if small bodied forage species preferentially used high temperature, low DO or high turbidity habitats and whether predator species avoided these locations. Prey species were more abundant in these extreme locations at both small (Blind Channel) and large (Lake Winnipeg) spatial scales, but predator avoidance was only documented in Blind Channel. The tolerances of fish species to moderate hypoxia (< 3 mg/L DO) was tested in the laboratory to verify that differences did exist among species and that the observed species distributions were not solely the effect of temperature. To quantify the potential for moderately hypoxic locations to provide a refuge from predation for small fish, a field manipulation was conducted in Blind Channel; hypoxic habitats were created without altering water temperature, decoupling the natural covariation between these two factors that occurs in aquatic systems. The abundance of small forage fish was higher in the hypoxic locations compared to controls and while predators still visited the hypoxic habitats, their mean visit duration was reduced from around 300 min to less than 1 min. An individual based computer model was used to test and illustrate current understanding of the relative importance of temperature, DO and turbidity on predator habitat selection decisions and fish community composition. The model showed that DO had a stronger effect on community composition than temperature, and that reduced foraging success from high turbidity was able to overpower the other two factors. Hypoxia affects habitat selection decisions by fish species and can provide refuges from predation and competition, helping maintain higher species diversity. Water temperature appears to have a weaker effect on fish distributions than DO while turbidity primarily affects visual predators, though the strength of turbidity effects depends on the magnitude and duration of individual events.

Because differences often exist between species in their tolerances to environmental conditions, locations characterized by extreme parameter values (i.e., high temperature, low DO, high turbidity) may provide refuges from predation or competition by altering the outcome of inter-species interactions. This thesis examined the effects and relative importance of water temperature, dissolved oxygen (DO) and turbidity on habitat use by fish species and resulting changes in community composition. The effects of abiotic factors on predator-prey interactions were tested using field surveys, laboratory experiments, field experiments and computer modeling. Field surveys were conducted in Blind Channel, Delta Marsh, Manitoba, and on Lake Winnipeg, Manitoba, to determine if small bodied forage species preferentially used high temperature, low DO or high turbidity habitats and whether predator species avoided these locations. Prey species were more abundant in these extreme locations at both small (Blind Channel) and large (Lake Winnipeg) spatial scales, but predator avoidance was only documented in Blind Channel. The tolerances of fish species to moderate hypoxia (< 3 mg/L DO) was tested in the laboratory to verify that differences did exist among species and that the observed species distributions were not solely the effect of temperature. To quantify the potential for moderately hypoxic locations to provide a refuge from predation for small fish, a field manipulation was conducted in Blind Channel; hypoxic habitats were created without altering water temperature, decoupling the natural covariation between these two factors that occurs in aquatic systems. The abundance of small forage fish was higher in the hypoxic locations compared to controls and while predators still visited the hypoxic habitats, their mean visit duration was reduced from around 300 min to less than 1 min. An individual based computer model was used to test and illustrate current understanding of the relative importance of temperature, DO and turbidity on predator habitat selection decisions and fish community composition. The model showed that DO had a stronger effect on community composition than temperature, and that reduced foraging success from high turbidity was able to overpower the other two factors. Hypoxia affects habitat selection decisions by fish species and can provide refuges from predation and competition, helping maintain higher species diversity. Water temperature appears to have a weaker effect on fish distributions than DO while turbidity primarily affects visual predators, though the strength of turbidity effects depends on the magnitude and duration of individual events.

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Made available in DSpace on 2014-10-09T12:49:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:43Z (GMT). No. of bitstreams: 1 10193.pdf: 8402979 bytes, checksum: 4460386cc762b5bc467885be0500df49 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN-SP / FAPESP:02/00356-5

Previous research has shown variation of thermal tolerance in clones of the aquatic crustacean Daphnia magna. In general, genotypes from regions with warmer climate possess a greater tolerance to high temperatures than those from colder climates. However, the mechanism by which they achieve this thermal tolerance is unclear. One possible explanation may lie in how the animals utilize polyunsaturated fatty acids (PUFAs), which are macromolecules essential for maintaining cell membrane fluidity and to prevent transition to gel-like phase. The need for PUFAs is exacerbated further in poikilothermic animals at colder temperatures. Therefore, it can be hypothesized that D. magna originating from colder climates would more readily uptake and incorporate PUFAs into their cell membranes when in a cold environment. This study examined twenty-one D. magna clones known to differ in thermal tolerance. A life-table experiment was conducted in order to see which clones could produce viable eggs at 10°C, when given a diet low in PUFAs (green alga Scenedesmus obliquus). Since egg-laying requires a significant investment of PUFAs, fecundity was used as the measurement of cold tolerance. Separately, eggs and their mothers from select clones were collected for lipid analysis. No D. magna clone showed success in every egg clutch during the experiment, although a few showed failures in every clutch. Clones from cold climate regions were not more likely to have more successful clutches when compared to those from warm climates. Lipid analysis via gas chromatography is ongoing and will compare lipid content in eggs and mothers at 25°C and 10°C with different diets—either low in PUFAs (S. obliquus) or high in PUFAs (heterokont alga Nannochloropsis limnetica). The lipid analysis will reveal if there is a lack of PUFA investment in eggs at cold temperatures by comparing unsuccessful cold-temperature eggs to successful cold-temperature eggs and warm-temperature eggs. Adult uptake of PUFAs can also be discerned by comparing adults with a low-PUFA diet at cold temperatures to those with a high-PUFA diet at cold temperatures and those at warm temperatures. This analysis will help understand trade-offs between high performance at different temperatures and mechanisms of plastic response to temperature.

Nowadays, asphalt mixtures can be complex and have many ingredients to meet economic, performance, and/or environmental requirements. Economic and environmental factors have been driving performance in the positive direction for rutting, but the negative direction for brittleness, cracking, and overall durability. Recent research has also shown that two of the national standards to assess aging or effects of environmental factors (AASHTO T283 and R30) do not always simulate the amount of aging or behaviors mentioned in the documents. Also, these methods generally view one environmental effect at a time, and do not consider simultaneous environmental effects on aging (e.g. oxidation, moisture, freeze-thaw effects). However, pavements are exposed to combined environmental effects. As such, there is a lack of understanding of the combined environmental effects on asphalt pavement, and improve methods are needed for laboratory settings, resulting in less than optimal design and materials selection protocols. This dissertation focuses on investigating combined environmental effects of oxidation, moisture, and freeze-thaw. The dissertation includes four years of field aging of plant mixed asphalt mixtures containing no recycled materials and three different warm mix technologies that were also exposed to eight laboratory conditioning protocols including individual and combined environmental effects of oxidation, moisture and freeze-thaw to investigate mixture properties measured at high, intermediate, and low temperatures with several mixture tests that were complimented with tests on recovered binder. Major findings are summarized below: • Cantabro mass loss captured individual and combined effects damage in laboratory and field conditions better than other mixture testing utilized herein and was recommended for mixture assessment. • Laboratory conditioning protocols with combined effects were the only ones able to consistently represent four or more years of field aging in the Mississippi climate. • Field aging of laboratory compacted specimens in PVC sleeves did not fully represent field aging of field placed pavement. Temperature and moisture conditions varied between the two cases. • Use of Cantabro mass loss and laboratory conditioning consisting of hot air, hot water, and freeze-thaw conditions was shown to provide combined effects improvements relative to at least some typical practices. Guidance was provided on how to use these tools to assess combined effects.

Twelve dairy cows were used to determine behavior with varying numbers of free stalls and length of feed trough. A least squares procedure, which regressed for numbers of observations, was adapted for obtaining dominance values. Available free stalls were 1.0, .83, .67, .50, .33 per cow. With 1.0 free stalls, linear feed trough was .5, .4, .3, .2, .1 m per cow changed at 7-day intervals. Cow behavior and locations were quantified by time-lapse photography at I-minute intervals during the last 3-days of each treatment. Spatial recommendations for dairy cattle can be greatly reduced. Behavior was altered only when less than .67 free stalls or .2 m of linear trough was available per cow. Minimum stalls needed per cow without altering daily free stall usage = [14.2 hours (average use)]/[hours per day free stalls are available to the herd X .93 (maximum. efficiency before crowding)]. Linear feed trough of .2 m appears adequate to ensure desired amount of eating time when individuals have access to feed in trough 21 hours per day. Estimated individual dry matter intakes were the same at .5 m and .25 m of trough per cow. Intake was affected by time spent eating for .25 m. In 10-variable models for various levels of competition, time spent eating, or in free stalls, and individual dry matter intake were described predominantly by production variables, not dominance values. Adrenal responsiveness to 200 IU adrenocorticotrophic hormone (ACTH) was determined by quantifying plasma corticosteroids in two groups of lactating Holstein cows. One group of 18 cows received ACTH via jugular catheter 0, 2, or 9 days after introduction to an established group in restricted space (3.96 m2 lot space and .67 free stalls per cow). Differences in total plasma corticoids (area under curve) in response to ACTH were not statistically different although corticoid response 2 and 9 days of stress tended to be greater than day O. A second group of 16 cows received ACTH at 0, 1, 2, or 3 days after introduction to a new group and crowding (2.97 m2 lot space and .5 free stalls per cow). Mean corticoid response to ACTH (area under the curve, ng/ml ± SD) were 161.6 ± 12.6, 158.2 ± 28.2, 227.7 ± 32.2 and 229.9 ± 40.3 for cows inject~d days 0, 1, 2, and 3 respectively, days 2 and 3 differed from day 0 (P<.OS). Bacteriological status of quarter milk samples was not changed by stress. In non-infected quarters of 24 stressed cows, 8 quarters increased above 150,000 somatic cells/ml while 5 quarters decreased below 150,000 cells/m1 of milk after 4 days of stress when compared to 2 and 6 days prior to stress. Stress did not affect milk production relative to controls. / Ph. D.

Because of increasing environmental demands, especially on dealing with products end of life phase, product manufacturers and designers must consider the future disposal of their products. For conventional materials like steel and aluminium well-functioning recycling methods exists. This is not the case for structures of polymer composites, which are used more extensively, especially for structures like vehicles and vessels. Several techniques do exist but they are not yet commercially available. The current disposal methods of polymer composites are landfill and incineration. Polymer composites are materials, which consist of several materials like fibre, matrix, and additives. In the form of sandwich constructions also foam core material is added. This circumstance complicates the waste treatment of composite materials. In this thesis a model for assessing possible future waste treatment techniques for polymer composites including sandwich structures is presented. The model is meant to be used as an aid for preparing future disposal for end of life products for planning waste treatment and for facilitating communication in contacts with waste receivers. Recommendations for waste treatment have been formed for a number of polymer composites. These recommendations are based on the analysis of costs and environmental effects and they compare different scenarios for mechanical material recycling and energy recovery by waste incineration. The result of this study points out material recycling as the preferable method for the main part of the studied materials. But this recommendation is strongly dependent on type of virgin material replaced by the recycled material. Energy recovery can also be considered if the polymer composite waste replaces coal, which is non renewable. Though incineration will always result in a cost for the waste producer. In the recommendations mentioned above no information concerning implementation of the different waste disposal techniques is included. Therefore, in this study a model for assessing possible waste disposal techniques for polymer composites is presented. The model is based on internal factors, which are related to the waste and to the processes. To implement the model relevant waste properties must be identified in order to fulfil the conditions set by the required processes involved. A case study was carried out using the proposed model for assessing different waste disposal techniques for the hull of the Visby Class Corvette in the Royal Swedish Navy. Six different techniques were studied for the hull structure. Since almost all the important waste properties were known and the waste was assessed to be treatable all the included techniques except one are shown to be usable in the future. Many investigations have pointed out material recycling as the best alternative considering environmental effects. This is also valid for polymer composite materials. Since recycling polymer composites is a complicated process, especially recycling thermoset composite it is important to aquire comprehensive information about the constituents of these materials. / QC 20101021

Foundries are most widely facilities all around the world, producing high amounts of castings. In this study, environmental impact of metal foundries was investigated toward a life cycle assessment (LCA) goal. Studies were conducted in two foundry plants in order to collect the inventory data. The difference between the plants regarding their processes was the application of secondary sand reclamation (SSR) in Plant 2. Application of SSR is indicated as a

Anaerobic digestion (AD) is an effective way to convert animal manures into profitable byproducts as well as to reduce the pollution of water, air, and soil caused by these wastes. Conventional high-rate anaerobic reactors cannot effectively process high-solids containing animal manures. The two-phase configuration for AD has several advantages over conventional one-phase processes such as increased stability of the process, smaller and cost efficient process configurations, etc. This study investigated the two-phase AD of dairy manure with particular emphasis on the effects of solids retention time (SRT), organic loading rate (OLR) and pH on anaerobic acidification of unscreened dairy manure / the effects of temperature on biogas production and the comparison of one-phase and two-phase system performance of AD. The results revealed that pre-acidification of dairy manure in daily-fed continuously-mixed reactors with no recycle led to substantial volatile fatty acids production. The optimum operational conditions for anaerobic acidification were determined as SRT and OLR of 2 days and 15 g VS/L.day. The pH control at a range of 5.0-5.5 was not found to be necessary for optimum acidification. Molecular analysis indicated that acidogenic bacteria population increased whilst the aerobic bacteria population decreased as time passed in acidogenic phase. The effect of temperature was clearly observed on biogas production efficiency. Two-phase configuration was determined more efficient than one-phase system. The biogas production in two-phase system was calculated to be 41% higher than that of the one-phase for the same OLR of 3.5 g VS/L.day. This translates into significant performance improvement and reduced volume requirement. This finding represents a further step in the achievement of wider use of simple anaerobic reactor configurations in rural areas.