Dissertations / Theses on the topic 'Temperate coast'
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1
Longabach, Leslie Jaye. "Movement of Selected Nearshore Temperate Reef Fishes Along California's Central Coast." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/401.
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Worldwide fisheries decline has spurred the utilization of new conservation and management approaches, including the implementation of marine reserves. The diversity of goals and expected outcomes should guide the marine reserve design process, coupled with a thorough understanding of the ecology of all species targeted for protection. Central California’s network of coastal marine protected areas (MPAs) was established in an environment of some uncertainty regarding the expected outcomes for temperate nearshore fish species, especially the Sebastes genus (rockfishes). Movement behavior of temperate reef-fishes plays an important role in the level of protection that a reserve will afford a species. Consistent small-scale movements (<10 km) and limited home range sizes decrease the likelihood that individuals will encounter fishing mortality. Conversely, large-scale movements outside of reserve boundaries may contribute to fisheries in surrounding waters (‘spillover’).
The current study sought to further elucidate the movement behavior of some shallow-water temperate reef fish species throughout California’s central coast, with goals of providing useful data for future MPA design processes. Tag-and-recapture methodology was utilized in order to observe fish movements, centered on a public participation program for acquiring information on recaptured tagged fishes. A total of 476 fishes representing 14 species were recaptured from a sample of 37,111 tagged (1.3%) over a five-year period spanning 2005-2009. The majority (75%) of distances traveled were less than one kilometer, however some species made consistent far-ranging travels on the order of hundreds of kilometers as well. Analyses of factors with potential for shaping movement behavior included geographic variation, source of recapture data, gear type, days at liberty, length, initial capture depth, handling condition, and fish density. Additionally, the applicability of tag-and-recapture methodology is examined as an effective source of fish movement information. The results of this research corroborate findings of previous studies as well as provide new insight into the movement patterns of some nearshore temperate reef species.
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Tecchiato, Sira. "Sediment dynamics of a temperate water carbonate system of the midwestern Australian coast." Thesis, Curtin University, 2014. http://hdl.handle.net/20.500.11937/21.
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An integrated analysis of sediment, hydrodynamic, habitat and geophysical data was carried out to reconstruct the sediment budget of two shallow (< 30 m) coastal embayments characterised by temperate water carbonate sedimentation. The interaction between coastal geomorphology, infrastructure and sediment transport pathways influences beach erosion. The linkage between natural processes and ongoing sediment bypassing and maintenance dredging activities was explained. This information is beneficial to support management of similar locations of regional Western Australia.
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Herbert, Roger J. H. "Testing hypotheses related to changes in abundance and distribution of warm-temperate invertebrates on rocky shores along the South coast of England." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342772.
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Affeld, Kathrin. "Spatial complexity and microclimatic responses of epiphyte communities and their invertebrate fauna in the canopy of northern rata (Metrosideros robusta A. Cunn.: Myrtaceae) on the West Coast of the South Island, New Zealand." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/771.
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Rain forest canopies are renowned for their very high biodiversity and the critical role they play in key ecological processes and their influence on global climate. Despite that New Zealand supports one of the most diverse and extensive epiphyte flora of any temperate forest system, few studies have investigated epiphyte communities and their invertebrate fauna along with factors that influence their distribution and composition. This thesis represents the first comprehensive study of entire epiphyte communities and their resident invertebrate fauna in the canopy of New Zealand’s indigenous forests. The aim of this study was to determine spatial patterns of epiphyte and invertebrate species richness, abundance and community composition in relation to abiotic variables, and in particular, the responses of these communities to elevated temperature and rainfall. This study was carried out in coastal lowland podocarp-broadleaved forests at two sites on the West Coast of the South Island of New Zealand. Samples from 120 mat-forming epiphyte assemblages located on inner canopy branches of 40 northern rata (Metrosideros robusta) trees were studied to characterise the component flora and fauna. Additionally, biomass, branch and tree characteristics and community responses to treatments designed to elevate temperature and rainfall to simulate predicted climate change were measured. This investigation revealed astonishing diversity and functional complexity of epiphyte and invertebrate life in this ecosystem. The 30.6 kg (dry weight) of epiphyte material collected contained a total of 567 species, 170 epiphyte and 397 invertebrate (excluding immature specimens and mites) species, including at least 10 species new to science and many undescribed species Epiphyte communities were found to be dominated by non-vascular plants (80 % of the total species richness), particularly liverworts and invertebrate communities were dominated with respect to abundance (~ 80 % of the total individuals) by Acari, Collembola and Hymenoptera (primarily ants) and functionally by scavengers and ants. Epiphyte and invertebrate communities were highly variable with respect to spatial patterning of species richness, abundance and composition across sites, among trees within sites and among branches within trees. Overall, a highly significant proportion, > 75 %, of the variance could be attributed to differences at the branch level, but these differences could not be explained by the environmental factors measured. There were no consistent relationships between the spatial pattern of epiphytes and invertebrates, or between vascular and non-vascular plants. However, there were significant positive correlations between epiphyte biomass and invertebrate species richness (r = 0.472; p < 0.0001) and abundance (r = -0.395; p < 0.0001), as well as non-living epiphyte biomass and scavenger species richness (r = 0.4; p < 0.0001). Microclimatic measurements taken on epiphyte mats were also highly variable with respect to temperature and relative humidity at similar physical locations within the same tree as well as across trees within sites. There was also considerable variation in the intensity and frequency of climatic extremes, although potentially harmful climatic conditions were experienced by all the epiphyte mats for which weather variables were measured. Negative correlations existed between both epiphyte and invertebrate community composition and increased temperatures expressed as cumulative degree days above 5˚C. However, variability was such that there was no direct evidence that increased temperature and rainfall treatments had an effect on invertebrate species richness, abundance or diversity. Northern rata host trees harbour an astonishingly diverse and complex canopy flora and fauna that is characterised by high spatial variability. Such variability highlights that to determine species distribution and community dynamics in canopy habitats in response to disturbance caused either by climate change or invasive species the structure of entire communities at different taxonomic and spatial scales, along with their responses to microclimatic factors, need to be studied. If such complexities are not taken into account, inappropriate interpretation may result in poor decisions concerning the conservation status, vulnerability and subsequent management of such unique ecosystems.
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Morvillez, Thierry. "Monitoring temperature variability along the California Coast using Acoustic Tomography." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA341180.
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Thesis (M.S. in Physical Oceanography) Naval Postgraduate School, September 1997."September 1997." Thesis advisor(s): Ching-Sang Chiu, Curtis A. Collins. Includes bibliographical references (p. 35-36). Also available online.
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Thomas, Andrew Charles. "Relationships between near-surface plankton distributions, hydrography, and satellite measured sea surface thermal patterns." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/29440.
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In-situ measurements of surface chlorophyll and zooplankton concentration are compared with in-situ hydrographic measurements and infrared satellite images of the west coast of British Columbia. Their relationships are quantified for a mid-summer and an early winter study period. Winter in-situ hydrographic data showed the shelf to be dominated by Vancouver Island Coastal Current water near-shore, Davidson Current water over the middle shelf, a frontal zone separating these regimes, and North Pacific water over the shelf break. The summer shelf was dominated by topographically induced upwelling in the southern portion of the shelf and stratified regions over the outer shelf and shallow banks further north. Strong northwest winds late in the summer study period induced upwelling along the entire shelf. The surface thermal signature of each of these regimes was identifiable in the satellite imagery.
Maximum winter concentrations of chlorophyll and zooplankton were associated with Vancouver Island Coastal Current water and southern portions of the frontal zone. Davidson Current water consistently had the lowest chlorophyll concentrations in the winter study area. Zooplankton concentrations decreased with increasing temperature and distance from shore. The correlation of loge transformed zooplankton concentrations with surface temperature allowed the satellite imagery to explain 49% of the sampled variance. The association of specific chlorophyll concentrations with each hydrographic regime enabled the satellite imagery, in conjunction with an image derived salinity model, to explain 55% of the sampled variance. Image derived plankton models allowed a spatial representation of predicted plankton concentration and the model error.
Summer zooplankton concentrations were not consistently related to satellite measured surface temperature but showed a qualitative association with higher chlorophyll concentrations around the outer edge of the upwelling area. Minimum chlorophyll concentrations were found in warm, stratified surface water and intermediate concentrations in the coldest, most recently upwelled water. Maximum concentrations occurred at intermediate temperatures. A least squares fit non-linear equation showed the satellite measured surface temperature patterns explained 72% of the sampled loge transformed chlorophyll variance. Distributions of both zooplankton and chlorophyll concentration retained their association with patterns of sea surface temperature during a wind driven upwelling event.
Multivariate cluster analysis of zooplankton taxonomic groups during both winter and summer showed spatial patterns of community composition matched satellite measured patterns of sea surface temperature over the middle and inner shelf. Over the outer shelf, spatial patterns of community structure appeared more closely associated with depth than surface thermal patterns.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Trapnes, Siri Hofstad. "Optimal Temperature Control of Rooms for Minimum Energy Cost." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemisk prosessteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22416.
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In this thesis was a room with direct heating in the floor and room modelled. The aim has been to minimize the energy cost of the room, assuming that the future energy price and weather forecast is known. The constrained optimization problem turned out to be linear, and the solution of the problem will always be on the upper or lower bounds of the inputs or states. The idea is to store heat when the energy price is low, and use it when the energy price is high. A switching time that ensures that the model starts the heating of the system at an optimal time in order to save energy costs is thus of importance to find.The problem was solved by using the matlab function fminsearch, and by assuming constant outdoor temperature. Two scenarios were analysed; 1) where only the floor heat is used to storage of heat, and 2) where both heaters are used to heat the system. In each scenario the length and starting point of the interval where the energy price is high was varied. This thesis show that storage of heat in the floor is preferred, apart from in the case where there is no time to heat before the peak interval begins, where both heaters in the floor and room should be used. For comparison, the optimization problem was also solved by using PI controllers, where the two inputs control the temperature in the floor and room respectively. It turned out that the result of the control problem when using PI will resemble the solution of the optimal control problem when using fminsearch.A couple of switching rules was derived in order to find the optimal switching time. This thesis show that the switching rules gives a good estimate of the switching time, apart from in the case where there is no time to heat. The switching rules was used in both methods (when using PI and fminsearch) and it was found that the obtained switching time is not far from the optimal solution in any of the methods. The optimization problem when using fminsearch was tested with varying outdoor temperature. It was seen that the solution from the optimal control problem will take the disturbance into consideration if it is varied before the peak period. On the other hand, the model do not allow for a variation in the outdoor temperature after the peak period.At last, the thesis show that the switching rule handle a variation in the disturbance before the peak period as good as the optimal control problem, but when the outdoor temperature becomes too cold will the result be poor.
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Dubois, Joël. "The influence of conditioning on internal checking of high-temperature dried Pacific Coast hemlock." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29750.
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The purpose of this study was to evaluate the effectiveness of steam conditioning immediately after drying to reduce internal checking resulting from high-temperature drying of Pacific Coast hemlock lumber. Three different levels of conditioning time, 2, 4 and 6 hours, were carried out on 2 inches wide by 4 inches thick by 3 feet long (51 mm by 102 mm by 0.91 m) , and on 4 inches wide by 4 inches thick by 3 feet long (105 mm by 105 mm by 0.91 m), specimens. For comparison purposes, controls of both sizes of specimens were also high-temperature dried without conditioning.
Analysis of the results indicated that internal checking was not significantly reduced by steam conditioning and was more likely to develop afterwards during storage at room temperature, and that total degrade observed in the "4x4" specimens was more excessive than that in the "2x4" ones.
The defective "4x4" specimens were found over-dried (below the targeted 12% moisture content) with high core-shell moisture content differences. More internal checking was found when the specimens' final moisture content ranged from 7 to 8%.Forestry, Faculty of
Graduate
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Cohen, Anne Louise. "A holocene sea surface temperature record in mollusc shells from the South African coast." Doctoral thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/22468.
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Summary in English.Bibliography: pages 140-163.
This thesis describes the construction of a Holocene history of sea surface temperatures in coastal regions of the southern Benguela and eastern Agulhas Bank of South Africa, using marine mollusc shells preserved in archaeological middens. Two independent palaeothermometers were employed: the traditional oxygen isotope technique and a new, alternative technique based on temperature-dependent changes in structure and mineralogy of the shell of a South African limpet species, Patella granularis. The relationship between the isotopic and structural aspects of shell composition, and habitat temperature was confirmed through examination of living populations.
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Rago, Thomas A. Collins Curtis A. Steger John. "Hydrographic data along the California coast from Pigeon Point to Cape San Martin May through July 1966 /." Monterey, Calif. : Naval Postgraduate School, 1997. http://catalog.hathitrust.org/api/volumes/oclc/36981499.html.
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Thesis (M.S.)--Naval Postgraduate School, 1997."January 1997." "Prepared for: Oceanographer of the Navy, OPNAV 096, Washington, DC 20392-5421." "NPS-OC-97-002." Includes bibliographical references (p. 152).
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Wilk, Gregory. "Liquid metal based high temperature concentrated solar power: Cost considerations." Thesis, Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54937.
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Current concentrated solar power plants (CSP) use molten salt at 565°C as a heat transfer and energy storage fluid. Due to thermal energy storage (TES), these solar plants can deliver dispatachable electricity to the grid; however, the levelized cost of electricity (LCOE) for these plants is 12-15 c/kWh, about 2.5 times as high as fossil fuel electricity generation. Molten salt technology limits peak operating temperatures to 565°C and a heat engine efficiency of 40%. Liquid metal (LM), however, can reach >1350°C, and potentially utilize a more efficient (60%) heat engine and realize cost reductions. A 1350 °C LM-CSP plant would require ceramic containment, inert atmosphere containment, additional solar flux concentration, and redesigned internal receiver. It was initially unclear if these changes and additions for LM-CSP were technically feasible and could lower the LCOE compared to LS-CSP. To answer this question, a LM-CSP plant was designed with the same thermal input as a published LS-CSP plant. A graphite internal cavity receiver with secondary concentration heated liquid Sn to 1400°C and transferred heat to a 2-phase Al-Si fluid for 9 hours of thermal energy storage. Input heat to the combined power cycle was 1350°C and had 60% thermal efficiency for a gross output of 168 MW. The cost of this LM-CSP was estimated by applying material cost factors to the designed geometry and scaling construction costs from published LS-CSP estimates. Furthermore, graphite was experimentally tested for reactivity with liquid Sn, successful reaction bonds, and successful mechanical seals. The result is switching to molten metal can reduce CSP costs by 30% and graphite pipes, valves, and seals are possible at least at 400°C.
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Greenwood, Karin C. "Sea surface temperatures around the souhtern [i.e. southern] African coast : climatological aspects and applications." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53583.
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Thesis (MSc)--Stellenbosch University, 2003.ENGLISH ABSTRACT: The oceanic and meteorological systems that characterize the southern African coastline are well-documented. In this thesis, these characteristics have been considered in conjunction with the analysis of a unique set of sea surface temperature (SST) data, obtained from measuring sites around the southern African coast, to determine the variability of SSTs in the immediate coastal region of southern Africa, and to demonstrate how this variability impacts on marinerelated economic activities. As part of the analysis process, various statistical techniques have been applied to the data over different time periods to establish the extent of the spatial variability of SSTs along the southern African coastline. From the results it has been possible to identify three distinctly different 'climatological' regions around the southern African coast; viz a cooler west coast region with a low annual and seasonal SST variability and a higher variability from day-ta-day, a warmer east coast region with a higher annual and seasonal SST variability and a lower variability from day-ta-day; and a temperate south coast region with a highly erratic annual, seasonal and day-ta-day SST variability. Furthermore, it has been possible to identify, albeit small, the existence of a high and a low frequency signal of 12-15 days and 40-60 days, respectively, in the three different regions. There is also evidence of the periodic occurrence of anomalously warm and cold SST events in all three regions, and a probability of <1.1% of a day-ta-day SST anomaly of >3°C (+3°C or- 3°C) occurring anywhere along the southern African coastline. The general causes of SST change have been discussed within the context of the heat budget equation. Furthermore, the effects of the variability of SST on the climate and marine life around southern Africa and the resulting impact on the various marine-related economic activities (such as aquaculture, air-sea rescue and power stations) have been identified, and shown to be both positive and negative.Finally, it should be noted, that economic infonnation relating to marine activities is closely guarded due to inter-industry competition. It has therefore been difficult to quantify the exact impact of the effects of SST variability on these activities.
AFRIKAANSE OPSOMMING: Die oseaniese en weerkundige stelsels wat die kuslyn van suidelike Afrika kenmerk is goed gedokumenteer. Die stelselkenmerke is in hierdie verhandeling ondersoek aan die hand van 'n unieke datastel van seeoppervlaktemperature (SST) afkomstig van meetplekke aan die kus van suidelike Afrika, ten einde die veranderlikheid van SST in die onmiddelike kusomgewing van suidelike Afrika vas te stel, asook om te demonstreer hoe hierdie veranderlikheid inwerk op seeverwante ekonomiese aktiwiteite. As deel van die proses van analise is verskeie statistiese metodes gebruik om die data oor verskeie tydperke te ontleed ten einde die omvang van ruimtelike veranderlikheid van SSTs langs die kus van suidelike Afrika te bepaal. Uit die resultate was dit moontlik om drie duidelike onderskeibare 'klimatologiese' streke aan die kus van suidelike Afrika te identifiseer; te wete 'n koeler weskusstreek met 'n lae jaarlikse en seisoenale SST-veranderlikheid en hoër dag-tot-dag veranderlikheid, 'n warmer ooskusstreek met 'n hoër jaarlikse en seisoenale SST-veranderlikheid en laer dag-tot-dag verandelikheid; asook 'n gematigde suidkusstreek met 'n hoogs wisselvallige jaarlikse, seisoenale en dag-totdag SST-veranderlikheid. Dit was verder moontlik om, alhoewel klein, die bestaan van lae en hoë frekwensie seine van 12-15 dae en 40-60 dae onderskeidelik in die drie streke te identifiseer. Daar is ook tekens van die periodieke voorkoms van anomale warm en koue SSTgebeurtenisse in al drie streke en 'n waarskynlikheid van <1.1% van die voorkoms van 'n dagtot- dag SST-anomaliteit van >3°C (+3°C of -3°G) op enige plek langs die suider Afrikaanse kuslyn. Die algemene oorsake van veranderings in SST is bespreek binne die konteks van die formule vir die behoud van hitte-energie. Die invloed van SST-veranderlikheid op die klimaat en die seelewe om suidelike Afrika en die gevolglike effek op mariene-verwante ekonomiese aktiwiteite (soos akwakultuur, lug-see-redding en kragstasies) is ook geïdentifiseer en is aangetoon om beide positief en negatief te wees Ten laaste dien dit gemeld te word dat ekonomiese inligting met betrekking tot mariene aktiwitweite goed bewaar word as gevolg van kompetisie in die bedryf. Dit was derhalwe moeilik om die presiese impak van die gevolge van SST-veranderlikheid op sodanige aktiwiteite te kwantifiseer.
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Knapp, Jarred Lee. "The effects of ocean acidification and temperature change on the West Coast rock lobster (Jasus lalandii)." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97802.
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Thesis (PhD)--Stellenbosch University, 2015.ENGLISH ABSTRACT: The West Coast rock lobster (WCRL), Jasus lalandii, is a critical marine fisheries resource for South Africa and may in future be negatively affected by the changes in seawater parameters associated with the ongoing anthropogenic carbon dioxide (CO2) emissions. These CO2 emissions have been linked to a global decrease in ocean pH (termed “ocean acidification”) and an increase in temperature. There are strong estimates that these changes are to worsen in coming centuries. This warranted research because of 1) the low current level of the resource (2.6% of pristine) and 2) the relatively unexplored physiological- and other biological responses of the WCRL to environmental stressors. This information is essential for the sustainable management of the resource by government scientists in times of global- and regional climate change. In the short term, it was found that the WCRL was able to rapidly and reversibly respond to acute changes in seawater pH (pH 7.4), this was achieved primarily through the active up-regulation of bicarbonate levels in the haemolymph. Maintaining extracellular pH protects oxygen transport mechanisms, which are sensitive to pH changes due to the large Bohr effect that this study also revealed, in the respiratory protein, haemocyanin of adult WCRL. The energy cost of actively maintaining extracellular pH, however, is expected to affect growth and potentially survival in the long term. This was tested on juvenile WCRL that were exposed to a reduced seawater pH of 7.3 (18.8 °C) over a period of 28 weeks. Results revealed that survival was not influenced and acid-base regulation in the hypercapnia-exposed lobsters was maintained throughout the duration of the trial, however, this led to a reduced growth rate. Subsequently, in order to replicate field conditions more closely, a combination of effects, namely seawater pCO2 (pH 8 and 7.3) and different temperatures (15.6 and 19 °C) on the growth of juvenile WCRL were assessed over an exposure period of 48 weeks in a second chronic trial. In contrast to the initial trial (28 weeks), where hypercapnia was assessed separately, lobsters exposed to hypercapnia had a higher growth rate than those at the same temperature exposed to a “natural” (normocapnic) seawater pH. The difference was interpreted as an indication that food availability/quality may negatively affect stress response, as feeding in the first trial was later considered “sub-optimal” in comparison to that of the second trial. In the latter, although both hypercapnia and temperature affected growth rates, temperature was the largest contributor to differences observed between treatments. The order of growth rates for lobsters from different treatments was: hypercapnia/high temperature > normocapnia/high temperature > hypercapnia/low temperature > normocapnia/low temperature. In this trial too, irrespective of treatment, lobsters were able to maintain extracellular pH within a relatively narrow range over the extent of the trial and survival was not negatively affected by hypercapnia or high temperature. In order to compare the sensitivity of juvenile WCRL to that of adults, with regards to the effect of changes in extracellular pH on oxygen transport, and to assess the impact of chronic hypercapnia, haemocyanin from juveniles was studied in detail after the first growth trial. This revealed that juvenile WCRL have a similar Bohr effect to that of adults. In addition, the haemocyanin of hypercapnia-exposed juveniles showed an increased affinity to oxygen caused by an intrinsic change in its molecular structure. This was interpreted as an energy-saving mechanism, because at the same time, haemocyanin concentration in these animals was lower than in normocapnic lobsters. At the termination of the second chronic trial, the immunological response to the combined stressors was assessed, namely total circulating haemocyte counts (THC) and the ability to clear/inactivate an introduced dose of a bacterium, Vibrio anguillarum. A pilot experiment on non-treated juveniles revealed a similar resting THC to that of other lobster species, and culturable V. anguillarum was rapidly cleared from their haemolymph. The effect of chronic exposure to a combination of effects, namely hypercapnia and different temperatures, was subsequently tested after termination of the second chronic trial. There were no differences between treatments in a) baseline THC (i.e. before bacterial challenge) and 2) the capability to clear culturable bacteria from haemolymph. The only difference was the circulating THCs post-bacterial challenge, as they were reduced in the hypercapnic-, high temperature treatment, compared with all other treatments. The reason is unknown, but it is speculated that it may have been linked to an increased metabolic demand in these lobsters. Overall, these results demonstrate the great plasticity of the WCRL at the molecular-, biochemical and physiological level. They provide important initial information for government fisheries scientists to aid in predicting future development of, and potential threats to the WCRL resource, as well as providing a platform from which the direction of future studies can be determined.
AFRIKAANSE OPSOMMING: Die Weskus-seekreef, Jasus lalandii, is ’n belangrike seevisseryhulpbron vir Suid-Afrika en kan in die toekoms negatief geraak word deur die veranderinge in seewaterparameters wat met voortgesette antropogeniese vrystellings van koolstofdioksied (CO2) verband hou. Hierdie CO2-vrystellings word met ’n wêreldwye daling in die pH van seewater (oftewel “oseaanversuring”) en ’n temperatuurstyging verbind. Alles dui daarop dat hierdie veranderinge in die volgende eeue sal vererger. Dít regverdig navorsing weens 1) die huidige skaarste aan dié hulpbron (2,6% van oorspronklike getalle), en 2) die betreklik onverkende fisiologiese en ander biologiese reaksies van die kreef op omgewingstressors. Hierdie inligting is noodsaaklik om staatswetenskaplikes in staat te stel om die hulpbron te midde van wêreldwye en streeksklimaatsverandering volhoubaar te bestuur. Op kort termyn word daar bevind dat die Weskus-kreef vinnig en omkeerbaar op akute veranderinge in die pH van seewater reageer (pH 7,4). Dít is hoofsaaklik deur die aktiewe opwaartse regulering van bikarbonaatvlakke in die hemolimf vasgestel. Die handhawing van ekstrasellulêre pH beskerm die meganismes wat suurstof vervoer, wat gevoelig is vir pH-veranderinge weens die beduidende Bohr-effek in die respiratoriese proteïen, hemosianien, by die volwasse kreef – nóg ’n bevinding van hierdie studie. Tog sal die energiekoste verbonde aan die handhawing van ekstrasellulêre pH na verwagting groei en moontlik ook oorlewing op lang termyn beïnvloed. Dít is getoets op jong Weskus-krewe wat oor ’n tydperk van 28 weke aan seewater met ’n verlaagde pH van 7,3 (18,8 °C) blootgestel is. Resultate dui daarop dat oorlewing nié geraak word nie, en dat suur-basis-regulering in die hiperkapnie-blootgestelde krewe vir die volle duur van die proef gehandhaaf is, hoewel dit tot ’n verlaagde groeitempo gelei het. Ten einde natuurlike omstandighede akkurater na te boots, is ’n kombinasie van uitwerkings, naamlik pCO2 van seewater (pH 8 en 7,3) en verskillende temperature (15,6 en 19 °C), op die groei van jong krewe oor ’n blootstellingstydperk van 48 weke in ’n tweede chroniese proefneming beoordeel. In teenstelling met die aanvanklike proef (28 weke), is hiperkapnie afsonderlik beoordeel en het krewe wat aan hiperkapnie blootgestel is ’n hoër groeitempo getoon as dié by dieselfde temperatuur wat aan seewater met ’n ‘natuurlike’ (normokapniese) pH blootgestel is. Dié verskil is vertolk as ’n aanwyser dat voedselbeskikbaarheid/-gehalte ’n negatiewe uitwerking op stresreaksie kan hê, aangesien voeding in die eerste proefneming later as ‘suboptimaal’ beskou is vergeleke met dié van die tweede proef. In die tweede proef, hoewel hiperkapnie én temperatuur groeitempo’s beïnvloed het, was temperatuur die grootste bydraer tot die verskille wat tussen behandelings opgemerk is. Die orde van die kreefgroeitempo’s met die verskillende behandelings was: hiperkapnie/hoë temperatuur > normokapnie/hoë temperatuur > hiperkapnie/lae temperatuur > normokapnie/lae temperatuur. In die tweede proef kon die kreef ook, ongeag behandeling, ekstrasellulêre pH vir die volle duur van die proefneming binne ’n betreklik beperkte bestek handhaaf, en het nóg hiperkapnie nóg hoë temperatuur ’n negatiewe invloed op oorlewing gehad. Om die gevoeligheid van jong Weskus-krewe met dié van volwasse krewe te vergelyk wat betref die uitwerking van veranderinge in ekstrasellulêre pH op suurstofvervoer, en om die impak van chroniese hiperkapnie te bepaal, is die hemosianien van jong krewe deeglik ná die eerste groeiproef bestudeer. Dít het aan die lig gebring dat die jong kreef ’n soortgelyke Bohr-effek as volwassenes toon. Daarbenewens toon die hemosianien van hiperkapnie-blootgestelde jong krewe ’n verhoogde affiniteit tot suurstof, wat deur ’n intrinsieke verandering in molekulêre struktuur veroorsaak word. Dít is as ’n energiebesparingsmeganisme vertolk, aangesien hemosianienkonsentrasie by hierdie diere terselfdertyd laer was as by normokapniese kreef. Aan die einde van die tweede chroniese proefneming is die immunologiese reaksie op die gekombineerde stressors beoordeel, naamlik totale sirkulerende hemosiettellings (THC) en die vermoë om ’n toegediende dosis van die bakterie Vibrio anguillarum op te ruim/te deaktiveer. ’n Toetseksperiment met niebehandelde jong krewe dui op ’n soortgelyke rustende THC as dié van ander kreefspesies, en kweekbare V. anguillarum is vinnig uit die hemolimf opgeruim. Die effek van chroniese blootstelling aan ’n kombinasie van faktore, naamlik hiperkapnie en verskillende temperature, is vervolgens na afloop van die tweede chroniese proef getoets. Die verskillende behandelings lewer dieselfde a) THC op die basislyn (met ander woorde voor toediening van die bakterie), en 2) opruimingsvermoë van kweekbare bakterieë uit die hemolimf op. Die enigste verskil was die THC’s ná toediening van die bakterie, wat laer was met die hiperkapniese hoëtemperatuurbehandeling as met alle ander behandelings. Die rede hiervoor is onbekend, maar hou vermoedelik verband met ’n verhoogde metaboliese vereiste by hierdie krewe. Oor die algemeen toon hierdie resultate die beduidende plastisiteit van die Weskus-seekreef op molekulêre, biochemiese en fisiologiese vlak. Dit bied belangrike aanvanklike inligting vir staatsvisserywetenskaplikes om die toekomstige ontwikkeling van én moontlike bedreigings vir die kreefhulpbron te voorspel, en voorsien boonop ’n platform van waar die rigting van toekomstige studies bepaal kan word.
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Dang, Thi Anh Thu. "Impact of ambient temperature on hospital admissions for acute myocardial infarction in central coast of Vietnam." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/123901/1/Thi%20Anh%20Thu_Dang_Thesis.pdf.
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Globally, there is evidence that extremes in temperature linked with climate change can exacerbate underlying health conditions and lead to hospitalization and premature death. This study examined the short-term effects of ambient temperature extremes on hospital admissions due to acute myocardial infarction (AMI) in three geographically dispersed provinces along the Central Coast region of Vietnam. We found that risk of AMI admission is associated with high and low temperatures, in part due to variation in sub-regional climate. Public health preparedness and multi-level interventions in communities and workplaces including factories and farms should attempt to reduce people's exposure to extreme temperature.
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Lawrence, Cloverley Mercia. "Ecology and ecophysiology of Zostera capensis: responses and acclimation to temperature." Doctoral thesis, Faculty of Science, 2020. http://hdl.handle.net/11427/32728.
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This study aimed to understand the ecology of the threatened, habitat-forming seagrass, Zostera capensis in Langebaan Lagoon, a marine protected area that forms part of the West Coast national park, South Africa; and the physiological strategies that allow this habitat to persist in sub- and supra-optimal temperatures. First, the environmental drivers responsible for spatial and temporal variability in Zostera and its associated macro-epifauna were determined. Secondly, the effects of temperature and the role of algal grazing in maintaining seagrass performance under temperature stress were investigated. Seasonal field collections of seagrasses and their associated macro-epifauna were undertaken, along with regular measurements of key environmental variables. Thereafter, mesocosm experiments were performed to measure the responses of Zostera to thermal stress and grazing using morphometry, fluorometry, chromatography and biochemistry. Significant seasonal variability in seagrass distributions with severe diebacks in summer were found, which influenced associated macro-epifauna communities. Populations responded to environmental stress by changing their growth form producing small-leaves in high densities in the high intertidal, while those in low intertidal and subtidal areas produced sparse, large-leaved populations. These distinct populations supported unique faunal diversities, which were dominated by grazing invertebrates. Temperature was a consistent driver of seagrass density and leaf size, while turbidity and exposure were key environmental factors that influenced macro-epifaunal patterns. Macro-epifaunal abundances were highly positively correlated with seagrass leaf width and biomass. Different growth forms displayed different responses to thermal stress, including a higher photosynthetic rate, and accumulations of carbon and nitrogen as phenolic compounds, in small- compared to large-leaved plants. This implies that large-leaved populations are more vulnerable to stress from fouling, which was evident in their larger epiphyte loads, compared to small-leaved populations. In addition, grazers were ineffectual at regulating epiphyte growth which increased under warming conditions. These findings suggest differences in resilience between sub-populations of Zostera, and attest to their capacity to recover from environmental stress. They further emphasise the significance of identifying characteristics and acclimation strategies that allow habitats to persist under climate change, and thus sustain biodiversity and productivity, as well as continue to provide important ecosystem services.
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Wong, Ing Liang. "Optimum and cost effective transparent insulation systems for office building applications in temperate and tropical climates." Thesis, University of Ulster, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443281.
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Novitzky, Peter. "Analysis of Mangrove Structure and Latitudinal Relationships on the Gulf Coast of Peninsular Florida." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1726.
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The coastline of Florida has been formed by geomorphic processes which have created suitable habitats for certain vegetation and organisms. One type of vegetation is the mangrove; this plant has a latitudinal range of 24° to 32° N latitude which is associated with local climatic changes (Mitsch 2000). There are three species of mangrove found in Florida: red (Rhizophora), black (Avicennia), and white (Languncularia) (USGS 2006). Mangroves have adapted overtime to live in different ecosystems which cause mangroves, along the Florida coast, of the same species not be the same.
Climatic variation causes individual mangrove trees have structural differences such as: tree height, diameter, and density; these variations are related to geographic location (Pool 1997, Schaeffer-Novelli 1990). Tree height is the measurement from the base of the tree trunk of the ground to the top of the tree. The diameter, also known as diameter at breast height (DBH), is the circumference of the tree trunk 1.21 meters from the ground. Density is the frequency of individual tress within predetermined distance. Florida's southwest coast has one of the world's biggest mangrove swamps called Ten Thousand Islands (Mitsch 2000). In northern Florida the mangrove swamps begin to mix with salt marsh vegetation, here mangroves are more like shrubs than trees (Mitsch 2000). The changes in individual mangrove structure could be a result of available freshwater and temperature.
This project was a quantitative analysis using published and original data for graph production to understand the structural variation of mangroves on Florida's gulf coast at different latitudes. Study sites were located in bays along the Gulf of Mexico. The gulf coast of Florida was the study area of this project because it is the northern latitudinal limit for mangroves and as the latitude changes mangrove plant structure changes (Mitsch 2000). The tree height, diameter, basal area, biomass, and densities were compared to the precipitation and temperature values to understand the effect climate has on mangroves.
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Budd, Chris. "USING MLC FLASH TO REDUCE SYSTEM COST IN INDUSTRIAL APPLICATIONS." International Foundation for Telemetering, 2017. http://hdl.handle.net/10150/626992.
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Storage devices based on Multi-Level Cell (MLC) NAND flash can be found in almost all computer systems except rugged, industrial systems; even though MLC is less expensive and more dense than devices based on standard Single-Level Cell (SLC) NAND flash, MLC’s lower write endurance and lower retention has led system designers to avoid using it. This avoidance is unnecessary in many applications which will never come close to the endurance limits. Furthermore, new processes are leading to storage devices with higher write endurance. System designers should review the specific use-model for their systems and can select MLC-based storage devices when warranted. The result is lower system costs without worry of data loss due to write endurance.
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Legaard, Kasey. "Temporal Variability of Satellite-Derived Chlorophyll and Sea Suface Temperature in the California Current." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/LegaardK2004.pdf.
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Qian, Lingyi. "Fabrication, characterisation and oxidation behaviour of Pt-based bond coats for high temperature applications." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/39531/.
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Over the years, platinum modified aluminide (PtAl) bond coats have been used in high temperature protection systems for commercial aircraft engines to protect turbine blades from high temperature oxidation and corrosion. In the process of operation, the oxidation and rumpling behaviours of the bond coats are the key factors in determining the lifetime of the thermal barrier coating. The latest development in aircraft engines has given rise to the need for bond coats with better oxidation and rumpling resistance at high temperature. This investigation aims to improve the oxidation and rumpling resistances of general PtAl bond coats by introducing ZrO2 nanoparticles, Ir and Pd additions: ZrO2 nanoparticles were incorporated into PtAl bond coats by co electrodeposition in an attempt to enhance their performance by exploiting the effect of reactive element (Hf, Zr, etc.) oxides. PtAl coatings with and without ZrO2 nanoparticles were deposited onto three commercially available Ni-based superalloys, namely, Mar-M-247, Mar-M-246 and Inconel 718. Thermal cycling oxidation tests were performed to evaluate the influence of ZrO2 addition and substrate composition. The addition of ZrO2 particles to PtAl coatings on Mar M 246 and Inconel 718 appeared to accelerate the growth of thermally grown oxide and reduced the rumpling of thermally grown oxide. However, when depositing PtAl coatings with ZrO2 nanoparticles on Mar-M-247, there was no changes, as mentioned above, in thermally grown oxide. Through the analysis of the coatings on different substrates, the interactions among Hf, Al and ZrO2 have been revealed and clarified, which offers a better understanding of the reactions of ZrO2 and the influence of substrate composition on bond coats. Ir and Pd coatings were deposited by means of electroplating and electroless plating respectively to explore the effects of other platinum group metals. Ir-modified PtAl coatings were investigated on Mar-M-246 with different vacuum annealing durations before the cyclic thermal test, which presented a significant reduction in growth rate of TGO and inward diffusion of Al in the oxidation test. Instead of oxygen diffusion barrier, Ir exhibited a diffusion barrier to Al possibly by forming a high temperature solid solution with Al, which has a higher melting point than general β-NiAl phase. As a result, it restrained the inward diffusion of Al and slowed down the outward diffusion of Al, thus improving the oxidation resistance. In addition, Ir concentration produced an effect on the diffusion barrier of Ir. When it is reduced lower than 15 wt.%, the barrier effect of Ir begins to degrade, which provides a better comprehension of the diffusion barrier effect of Ir. However, Pd-modified PtAl coating did not strengthen oxidation resistance, which may be caused by the phosphorus precipitates generated from the electroless plating process. ZrO2 and Pd-modified PtAl bond coats were further investigated with 8 wt.% yttria stabilised zirconia top coat. Comparison between conventional PtAl and high velocity oxygen fuel sprayed NiCoCrAlY bond coats was made as well. Isothermal and cyclic thermal oxidation tests were carried out to evaluate the prepared bond coats. ZrO2 modified PtAl coating showed the best oxidation and rumpling resistance in cyclic thermal oxidation, while Pd-modified PtAl coating was worse than conventional PtAl coating and better than the NiCoCrAlY coating. It has been observed that ZrO2- and Pd-modified PtAl bond coats are affected by different methods of oxidation test. Isothermal oxidation has a greater impact on ZrO2- and Pd-modified PtAl bond coats. The difference is considered to be a consequence of long term annealing in isothermal oxidation, which leads to a fast grain boundary diffusion of Al.
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Blanchard, Allan (Allan B. ). "Enabling multi-cation electrolyte usage in LMBs for lower cost and operating temperature." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/80900.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2013.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 60-61).
Alloy anodes form a promising path to the use of multi-cation electrolytes by increasing chemical stability. In this study, a lithium-magnesium alloy anode was developed such that lower cost and lower melting temperature multi-cation electrolytes could be incorporated in liquid metal batteries (LMBs). In a first part of this work, Lithium-magnesium was proven to be a viable anode in a standard uni-cation (Li+) Li-Mg/LiCl-LiF-LiI/Sb-Pb battery. SEM and EDS confirmed the stability of this anode with respect to the cathode (Sb-Pb) and the standard uni-cation electrolyte. Performance metrics (voltage, efficiencies, etc.) for the Li-Mg anode cell were found to be comparable to the analogous pure Li anode system. In a second part of this work, using the alloyed Li-Mg anode, we demonstrated successful cycling of cells using multi cation electrolytes in Li-Mg/LiBr-KBr/Sb-Pb and Li-Mg/LiCl-KCl/Sb-Pb LMBs. Each of these multi-cation electrolyte systems boasted an active materials energy cost of (<150$/kWh), which is less expensive than the metric cost to implement storage batteries in the electrical grid.[1] These results open the door to incorporating lower cost and lower melting temperature electrolyte candidates in LMBs by using alloyed anodes.
by Allan Blanchard.
S.B.
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DRENSKY, GEORGE KERILOV. "AMBIENT AND HIGH TEMPERATURE EROSION INVESTIGATION OF MATERIALS AND COATINGS USED IN TURBOMACHINERY." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022846322.
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Fong, Alan Ming-Lun. "A study of thermal comfort and cost effectiveness of stratum ventilation." Thesis, De Montfort University, 2015. http://hdl.handle.net/2086/11169.
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This studyh focuses on thermal comfort and cost effectiveness of stratum ventilation in subtropical Hong Kong Special Adminstation Region (HKSAR). The need for studying thermal comfort with various air distribution strategies becomes a significant issue recently due to climate change, increasing energy prices and the governmental energy efficiency policy. Stratum ventilation, with air supplied at breathing level, can probably provide satisfactory thermal comfort at a relatively elevated indoor temperature in which less energy use is consumed. It seems that only limited studies on the evaluation of neutral temperature, which is a condition of neither slightly warm nor slightly cool, are supported by actual human comfort surveys. Moreover, study on the related thermal comfort and cost effectiveness as other paradigms in comparison with the mixing and displacement air distribution design is rare. New environmental chamber of laboratory-based air-conditioning systems has been developed for investigating the actual benefit of cost effectiveness and balance of thermal comfort satisfaction with the stratum air distribution strategy under subtropical climates. American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 7-point questionnaires have been collected from human comfort tests so as to estimate the neutral temperature of stratum ventilation in comparison with mixing and displacement ventilation at pre-set conditions. The neutral temperatures of HKSAR people under the mode of mixing, displacement, stratum, modified-stratum-1, modified-stratum-2, and modified-stratum-3 are found to be 24.6℃, 25.1℃, 25.6℃, 26.0℃, 27.1℃ and 27.3℃ at 10 air change per hour (ACH) respectively, which become 24.8℃, 25.3℃, 26.6℃, 27.4℃, and 27.9℃ at 15 ACH respectively. Life cycle assessment results in 10 service year indicate that 7.73% and 7.32% of cost reduction, and 14.52% and 11.91% of greenhouse gas emission reduction in stratum ventilation by comparing with mixing and displacement ventilation. As a result, stratum ventilation should be the best option on both of cost reduction, and less carbon emission in small-to-medium size air-conditioned space for new building and retrofitting existing works.
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Skillman, John B. "ENSO forced variations of the sea surface temperature and adjusted sea level along the west coast of the United States." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/39746.
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Approved for public release; distribution is unlimited.Daily coastal surface temperature and adjusted sea level data for the period 1955-1988 were used to characterize the surface temperature and adjusted sea level anomalies, and the propagation of features along the west coast of the United States during El Nino-Southern Oscillation (ENSO). The strong ENSO years examined were 1957-58, 1972-73, and 1982-83. Moderate ENSO years used were 1966, 1976, and 1987. To look at regional differences in the signals, the time series of daily coastal surface temperature and adjusted sea level were divided into three distinct regions: the southern region (i.e., Southern California), the central upwelling region (i.e., Central California), and the northern region (i. e., Northern California, Oregon, and Washington). The anomaly series were compared with cross-spectral analysis. Phase speeds and wavenumbers were estimated from the difference in phase between La Jolla and the other stations as a function of frequency band. These were used to characterize the structure of waves associated with the propagation. of the positive surface temperature and adjusted sea level anomalies. These wave characteristics were found to be consistent with coastally trapped internal Kelvin waves, due to their phase speed, wavelength and non-dispersive nature. Phase speeds for frequencies corresponding to 4-20 day periods were 60-100 km/day, based on temperature and sea level. A regression of wavenumber against frequency gives phase speeds of about 65-85 km/day, that is consistent with Kelvin wave theory for typical west coast ocean structure and bathymetry. During ENSO episoddes, strong warm surface temperature anomalies were found to exist along the west coast and were supported by high adjusted sea level anomalies. The use of daily observations was advantageous over traditional monthly data for this analysis.
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Emanuel, Martin Phillippe. "Interactive effects of pH, temperature and exposure period on native and invasive mussels from the West Coast of South Africa." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/6626.
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Global warming and ocean acidification due to an increase in anthropogenic carbon dioxide can impact marine calcifying organisms. Shells of marine calcifying organisms protect their internal soft tissue and may be key in determining the susceptibility of marine calcifiers to these environmental stressors. To test this, the effects of pH, temperature, exposure period and their interactions on the performance of native and alien mussels with varying shell thickness was studied. Listed in order of decreasing shell thickness, I compared shell dissolution, shell growth, shell breaking force and condition index of Aulacomya ater, Choromytilus meridionalis (both native), Mytilus galloprovincialis and Semimytilus algosus (both invasive) found on the Western Cape coast of South Africa. Live mussels and bare shells were exposed to seawater temperatures of 14°C and 20°C set at two pH levels (7.5 and 8.0) for roughly 40 days. Live mussels were either exposed to aerial drying for four hours per day or fully submerged for the duration of the study. The results suggest that shell thickness determines the susceptibility of mussels to environmental stressors, in terms of shell dissolution and breaking force, but does not affect internal growth. Invasive mussels showed increased shell dissolution at low pH but their growth rates were unaffected. They also exhibited higher condition indices than native mussels under low pH and high temperatures. On the other hand, the thicker shelled native mussels showed no significant changes in shell dissolution among the treatments and exhibited increases in growth rates in low pH treatments. C. meridionalis, being cold water adapted, exhibited a reduction in condition index in high temperature treatments. The study indicates that native and invasive mussels have different compensatory mechanisms to respond to anthropogenic impacts. These mechanisms allow them to maintain their specific life history strategies under short term exposure to warming and acidification. It was also elucidated that mussels exposed to low temperature aerial conditions exhibit increased shell and tissue growth as periodic exposure minimises the deleterious effects of ocean acidification and warming. The findings suggest that native and invasive mussels respond differently to ocean acidification and warming depending on their specific physiologies and life history strategies.
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Meriö, L. J. (Leo-Juhani). "The measurement and modeling of snowmelt in sub-arctic site using low cost temperature loggers." Master's thesis, University of Oulu, 2015. http://urn.fi/URN:NBN:fi:oulu-201509031948.
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The aim of this thesis was to study and test how inexpensive temperature loggers can be used to measure the local and microscale variability of the snowmelt processes and rates in subarctic Pallastunturi fell area. The loggers were deployed on six test plots with varied topography, vegetation and terrain type. In each test plot the sensors were installed in five test points on the ground and above the ground on fixed height of 30 cm. During the installation, the snowpack height and density were measured from each test point. The temperature was recorded at 15 min interval from 19th of April to 15th of June 2014. The melting processes and rates were determined using diurnal temperature fluctuations of the sensors. Validity of the results was evaluated using snow height data from adjacent measurement stations maintained by Geological Survey of Finland, equipped with acoustic snow sensor. Additionally an empirical snow model was employed to test the determined melt rates using climate data from Finnish Meteorological Institute as input for the model. The results exposed the difference in timing and variability of the snowmelt. Timing was earlier in southern slopes and slightly earlier in open areas compared forests. The variability of the melt timing was highest at forested plots whereas it was lowest at an open mire. The results agreed reasonably well with the measurement results from the acoustic measurement station but gave also information about the spatial variability of the melt. Determined melt rates were used in an empirical degree-day snow model to estimate the snow water equivalent between 1st of September 2013 to 31st of August 2014. The root mean squared error between the model and measured dates for the end of permanent snow cover for the data from 24 test points was 3.74 days. The microscale accuracy of the method was highest in relatively homogenous and open terrain type, such as open mire, where the accuracy was approximately one day. In more complex terrain types with forests the method was less accurate, thus median determined melt rates are recommended to be used in such conditions. Solar radiation absorbed by the logger resulting to increased melt speed near the sensor was assessed to be among the most significant sources of uncertainty for the method. Other significant factors resulting to inaccuracy in melt rate determination include possible dislocation of the upper sensor due to snow compression during the spring and unknown physical properties of the snow during the final melt period. Despite the uncertainties, regions where the current snow measurements are not representative and remote ungauged catchments are assessed to be especially suitable for using the method presented in this study. Loggers equipped with wireless connections could be additionally used for real-time tracking of the snow accumulation and meltTyön tavoitteena oli selvittää ja testata miten edullisia lämpötilatallentimia voidaan käyttää lumen sulannan prosessien ja nopeuden mittaamiseen subarktisella Pallaksen tunturialueella. Lämpötila-anturit sijoitettiin kuudelle koealueelle, joiden topografia, kasvillisuus ja maastotyyppi vaihtelevat. Tallentimet asennettiin jokaisella koealueella viiteen koepisteeseen sekä maahan että 30 cm vakiokorkeudelle maanpinnasta. Asennuksen aikana mitattiin lumipeitteen korkeus ja tiheys jokaiselta koepisteeltä. Anturit ohjelmoitiin tallentamaan lämpötila 15 min välein 19.4.–15.6.2014 välisenä aikana. Lumen sulannan nopeus määritettiin antureiden päivittäisen lämpötilavaihtelun avulla. Tulosten oikeellisuutta arvioitiin vertaamalla niitä koealueella sijaitsevien Geologian tutkimuskeskuksen akustisien sensorien mittaamiin lumenkorkeustietoihin. Lisäksi määritettyjä lumen sulannan nopeutta kuvaavia astepäivätekijöitä testattiin empiirisellä lumimallilla, jonka lähtötietoina käytettiin Ilmatieteen laitoksen ilmastoaineistoa. Tulokset paljastivat lumen sulannan ajankohdan sekä sen vaihtelun. Sulaminen tapahtui aikaisemmin eteläisillä rinteillä verrattuna pohjoisiin sekä hieman aikaisemmin avoimilla alueilla kuin metsässä. Sulamisajankohdan vaihtelu oli suurinta metsäalueilla ja pienintä avoimella suolla. Tulokset vastasivat kohtuullisen hyvin akustisella lumenkorkeussensorilla mitattuja arvoja, mutta lisäksi saatiin tietoa sulannan alueellisesta vaihtelusta. Mittaustulosten avulla määritettyjä sulamisnopeuksia ja empiiristä astepäivätekijämallia hyödyntäen mallinnettiin lumen vesiarvo jokaisessa koepisteessä välillä 1.9.2013–31.8.2014. Keskineliövirheen neliöjuuri (RMSE) mallinnetun ja mitatun pysyvän lumipeitteen lähtemispäivämäärän välillä oli 3.74 päivää. Paras tarkkuus (noin yksi päivä) saavutettiin suhteellisen homogeenisellä ja avonaisella alueella, avoimella suolla. Topografian ollessa vaihtelevampaa sekä metsäisillä alueilla menetelmän tarkkuus heikkeni, mutta käyttämällä koealuekohtaista sulamisnopeuden mediaania tarkkuutta saatiin parannettua. Merkittävimpiä menetelmän epävarmuustekijöitä arvioitiin olevan auringonsäteily, joka lämmittää lämpötilatallenninta ja sulattaa lumen nopeammin tallentimen läheisyydestä. Lisäksi osassa koepisteitä havaittu ylempien tallentimien lumen painumisen aiheuttama siirtyminen alaspäin sekä sulannan loppuvaiheessa tuntemattomat lumen fysikaaliset ominaisuudet voivat aiheuttaa merkittävää virhettä sulamisnopeuden arvioimisessa. Epävarmuustekijöistä huolimatta menetelmän arvioidaan sopivan erityisesti alueille, joilla tämän hetkiset lumimittaukset eivät ole edustavia, sekä etäisille valuma-alueille, joita ei aikaisemmin ole mitattu. Langattomalla yhteydellä varustettuja lämpötilatallentimia voitaisiin lisäksi käyttää reaaliaikaiseen lumen kertymisen ja sulamisen seurantaan
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Tighe, Susan Louise. "An integrated model to assess asphalt cement quality on low-temperature performance and life cycle cost." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0026/NQ51232.pdf.
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Kingsbury, Christopher W. "Fuel cycle cost and fabrication model for fluoride-salt high-temperature reactor (FHR) "Plank" fuel design optimization." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54337.
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The fluoride-salt-cooled high-temperature reactor (FHR) is a novel reactor design benefitting from passive safety features, high operating temperatures with corresponding high conversion efficiency, to name a few key features. The fuel is a layered graphite plank configuration containing enriched uranium oxycarbide (UCO) tri-structural isotropic (TRISO) fuel particles. Fuel cycle cost (FCC) models have been used to analyze and optimize fuel plate thicknesses, enrichment, and packing fraction as well as to gauge the economic competitiveness of this reactor design.
Since the development of the initial FCC model, many corrections and modifications have been identified that will make the model more accurate. These modifications relate to corrections made to the neutronic simulations and the need for a more accurate fabrication costs estimate. The former pertains to a MC Dancoff factor that corrects for fuel particle neutron shadowing that occurs for double-heterogeneous fuels in multi-group calculations. The latter involves a detailed look at the fuel fabrication process to properly account for material, manufacturing, and quality assurance cost components and how they relate to the heavy metal loading in a FHR fuel plank.
It was found that the fabrication cost may be a more significant portion of the total FCC than was initially attributed. TRISO manufacturing cost and heavy metal loading via packing fraction were key factors in total fabrication cost. This study evaluated how much neutronic and fabrication cost corrections can change the FCC model, optimum fuel element parameters, and the economic feasibility of the reactor design.
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Lymburner, Alannah. "Differences in Thermal Quality Affect Investment in Thermoregulation by Lizards." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39115.
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Body temperature affects physiological processes and, consequently, has a large impact on fitness. Lizards need to thermoregulate behaviourally to maintain their body temperature within a range that maximizes performance, but there are costs associated with thermoregulation. The thermal quality of an environment is a major cost of thermoregulation because it directly affects the time and energy that must be invested by an individual to achieve and maintain an optimal body temperature for performance. According to the cost-benefit model of thermoregulation, lizards should only thermoregulate when the benefits outweigh the costs of doing so. Thus, in habitats of poor thermal quality, individuals should thermoregulate less. Using two systems, an elevational gradient and a pair of habitats that vary in the amount of solar radiation they receive, I tested the hypothesis that investment in thermoregulation by lizards is dictated by the associated costs of thermoregulating. Temperature, and thus thermal quality, decreases with elevation. I found a significant positive relationship between elevation and effectiveness of thermoregulation of Yarrow’s spiny lizards (Sceloporus jarrovii). When comparing thermoregulation of ornate tree lizards (Urosaurus ornatus) living in the thermally superior open-canopy wash habitat or the closed-canopy upland habitat, I found that habitat type was a significant predictor of accuracy of body temperature. In the poorer quality habitat, lizards had smaller deviations of body temperature from their preferred temperature range. Overall, I conclude that the thermal quality of a lizards’ environment impacts their thermoregulation in the opposite direction than predicted by the cost-benefit model of thermoregulation. This suggests that the disadvantages of thermoconformity may be greater than the costs thermoregulating as habitats become more thermally challenging.
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Kimball, Matthew Eric. "Using temperature tolerance to predict distribution and overwintering success of lionfish (Pterois volitans/miles complex) on the east coast of the United States." Connect to this title online, 2003. http://www.lib.ncsu.edu/theses/available/etd-07182003-010123/.
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Chalasani, Trishala. "AUTOMATED ASSESSMENT FOR THE THERAPY SUCCESS OF FOREIGN ACCENT SYNDROME : Based on Emotional Temperature." Thesis, Blekinge Tekniska Högskola, Institutionen för datalogi och datorsystemteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-15330.
Full textAbstract:
Context. Foreign Accent Syndrome is a rare neurological disorder, where among other symptoms of the patient’s emotional speech is affected. As FAS is one of the mildest speech disorders, there has not been much research done on the cost-effective biomarkers which reflect recovery of competences speech. Objectives. In this pilot study, we implement the Emotional Temperature biomarker and check its validity for assessing the FAS. We compare the results of implemented biomarker with another biomarker based on the global distances for FAS and identify the better one. Methods. To reach the objective, the emotional speech data of two patients at different phases of the treatment are considered. After preprocessing, experiments are performed on various window sizes and the observed correctly classified instances in automatic recognition are used to calculate Emotional temperature. Further, we use the better biomarker for tracking the recovery in the patient’s speech. Results. The Emotional temperature of the patient is calculated and compared with the ground truth and with that of the other biomarker. The Emotional temperature is calculated to track the emergence of compensatory skills in speech. Conclusions. A biomarker based on the frame-view of speech signal has been implemented. The implementation has used the state of art feature set and thus is an unproved version of the classical Emotional Temperature. The biomarker has been used to automatically assess the recovery of two patients diagnosed with FAS. The biomarker has been compared against the global view biomarker and has advantages over it. It also has been compared to human evaluations and captures the same dynamics.
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Makame, Makame Omar. "Vulnerability and adaptation of Zanzibar east coast communities to climate variability and change and other interacting stressors." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1011895.
Full textAbstract:
Climate variability and change as well as sea level rise poses significant challenges to livelihoods, water and food security in small island developing states (SIDSs) including the Zanzibar Islands. Thus, without planned strategic adaptation, the future projected changes in climate and sea level will intensify the vulnerability of these sensitive areas. This thesis is based on research conducted in two sites located in the north eastern parts of each island, namely Kiuyu Mbuyuni, Pemba Island and Matemwe, Unguja Island. The research focused firstly on assessing the vulnerability of these two coastal communities to climate variability and change and other stressors. This included investigation of (1) the perceptions of fishers, farmers and seaweed farmers regarding climate stressors and shocks and associated risks and impacts, (2) existing and possible future water and food security issues, and (3) household's access to important livelihood assets. This was followed by an exploration of the coping and adaptive responses of farmers, fishers and seaweed farmers to perceived shocks and stresses and some of the barriers to these responses. Lastly, an analysis of the implications of the findings for achieving sustainable coastal livelihoods and a resilient coastal community was undertaken. The general picture that emerges is that local people along the east coasts of both islands are already vulnerable to a wide range of stressors. Although variability in rainfall is not a new phenomenon in these areas, increasing frequency of dry spells and coastal floods resulting from the influence of El Niño and La Niña events exert enormous pressures on local activities (fishing, farming and seaweed farming) which are the crux of the local economy. The main argument of the study is that the nature and characteristics of these activities are the main source of sensitivity amongst these communities and this creates high levels of vulnerability to climate shocks and trends. This vulnerability is evidenced by the reoccurrence of localised food shortages and the observed food and water insecurity. The study found that food insecurity is a result of unreliable rainfall, drought and seasonality changes. These interacted with other contextual factors such as poor soil, low purchasing power and the lack of livelihood diversification options. In addition to exposure to these almost unavoidable risks from climate variability, the vulnerability of the local communities along the east coasts is also influenced by the low level of capital stocks and limited access to the assets that are important for coping and adaptation. Despite this, some households managed to overcome barriers and adapt in various ways both within the three main livelihood sectors (fishing, farming and seaweed farming) as well as through adopting options outside these sectors resulting in diversification of the livelihood portfolio. However, the study found that most of the strategies opted for by fishers, farmers and seaweed farmers were mainly spontaneous. Few planned adaptation measures supported by state authorities were observed across the sites, with the exception of the provision of motorised boats which were specifically meant to increase physical assets amongst fishers, reduce pressure in the marine conservation areas and prevent overfishing in-shore. Furthermore, numerous strategies that people adopted were discontinued when further barriers were encountered. Interestingly, some of the barriers that prevented households adapting were the same ones that forced households that had responded to abandon their adaptations. To increase resilience amongst east coast communities to current and future predicted changes in climate and sea level, the study argues that traditional livelihood activities (fishing, farming and seaweed farming) need to be better supported, and access to a range of livelihood assets improved. This may be achieved through increased access to local sources of water and facilitation of rainwater harvesting, expanding the livelihood options available to people and increasing climate change awareness, and access to sources of credit.
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Godfrey, R. W., W. D. Preston, S. R. Joseph, L. LaPlace, P. E. Hillman, K. G. Gebremedhin, C. N. Lee, and R. J. Collier. "Evaluating the impact of breed, pregnancy, and hair coat on body temperature and sweating rate of hair sheep ewes in the tropics." AMER SOC ANIMAL SCIENCE, 2017. http://hdl.handle.net/10150/625393.
Full textAbstract:
The objective of this study was to evaluate the effect of pregnancy, breed, and hair coat on body temperature and sweating rate (SR) of hair sheep. St. Croix White (STX; = 9) and Dorper × STX (DRPX; = 9) ewes (3.6 yr of age) were evaluated over 4 d at 126 d of gestation (PREG) and over 4 d at 46 d postpartum (OPEN) in the shade and sun and in the morning (AM; 0900 to 1200 h) and afternoon (PM; 1300 to 1600 h) after a 20 min acclimation to each condition on each day. Data loggers recorded vaginal temperature (VT) at 10-min intervals for 96 h. Rectal temperature (RT) was measured using a digital veterinary thermometer, and respiration rate (RR) was measured as breaths per minute (bpm). Sweating rate was calculated from measured air properties passing over a shaved (300 cm) and unshaved area of the ewes' body using a portable calorimeter. Data were analyzed using GLM procedures of SAS (SAS Inst. Inc., Cary, NC) with breed, pregnancy status, sun exposure, and time of day as main effects. Mean temperature, relative humidity, temperature-humidity index, wind speed, and solar radiation on the days of data collection were 28.2°C, 82.8%, 80.3, 4.2 km/h, and 237.5 W/m, respectively. There was no difference ( > 0.10) in RT, RR, and SR between DRPX and STX ewes. The PREG ewes had lower RT ( < 0.007) and SR ( < 0.0001) and higher RR ( < 0.007) than OPEN ewes (38.5 ± 0.2 vs. 39.1 ± 0.2°C, 70.2 ± 3.1 vs. 88.3 ± 3.1 g⋅m⋅h, and 79.5 ± 2.2 vs. 72.1 ± 2.2 bpm, respectively). During the PM, RR, RT ( < 0.05), and SR ( < 0.006) were higher than in the AM. In the sun, RR ( < 0.001) and SR ( < 0.0001) were higher than in the shade, but there was no difference ( > 0.10) in RT. There was no difference in SR ( > 0.10) between the shaved and unshaved area of the ewe. The DRPX ewes had higher ( < 0.0001) VT than STX ewes. The PREG ewes had higher ( < 0.001) VT than OPEN ewes during the night time and lower VT than the OPEN ewes during the day time ( < 0.0001). The OPEN ewes had a greater ( < 0.009) daily range of VT than PREG ewes did (2.5 ± 0.4 vs. 1.1 ± 0.4°C, respectively), but there was no breed difference ( > 0.10). Hair coat did not have an influence on the SR of the ewes, and PREG ewes appeared to use increased respiration as opposed to sweating to help control RT. The narrower range of body temperature, measured as VT, of PREG compared to OPEN ewes may be a protective mechanism for the developing fetus.
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Lander, Jasmine. "Cost-efficient approaches to measure carbon dioxide (CO2) under different environmental factors such as temperature and humidity using mini loggers." Thesis, Linköpings universitet, Institutionen för tema, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-165993.
Full textAbstract:
Fluxes of carbon dioxide (CO2), being a major greenhouse gas, are of great importance to understand and monitor. Findings have shown that while CO2 emissions enhanced by humans triggered the greenhouse gas effect, several significant CO2 fluxes in nature that are climate sensitive may still be poorly constrained, especially those from inland waters and its surrounding soils and sediments. This including different processes such as decomposers degrading organic material. At present, direct measurements of CO2 from soils, waters or CO2 concentrations in surface water, are typically labour intensive or require costly equipment. Therefore, small inexpensive CO2 mini loggers, originally made for indoor air quality monitoring, are for this project being developed further for field use, as a convenient equipment to measure CO2 emissions. However, a requirement is that the mini loggers are stable and robust against interference by other air components, including water vapour, and physical factors such as temperature. Therefore, the mini loggers were for this project studied further under different environmental conditions such as temperature and humidity in a controlled environment. The results were analysed using multiple regression analysis where the CO2 concentration (CO2), measured by the LGR instrument, versus the logger IR signal (IR), temperature (T) and relative humidity (RH) were studied. Unlike some previous studies, this project studied a large CO2 concentration interval (400 – 10 000 ppm). The results show that there was a strong regression for IR versus CO2. The regression for both RH and the T was on the other hand very weak. However, there were factors that could have affected the mini logger. This since it was noticed that the mini loggers’ ability to calculate the CO2 concentration was worsened when the humidity was increased during the experiments. It is believed that the cause was condensed water, gathering in the inner parts of the mini logger. This because the sensor chamber had a lower temperature than the hot air entering the sensor chamber from the humidity bottle, together with the CO2, leading to condensation. Hence, prevention of condensation inside the measurement cell is important. However, the results from the analysis shows that the factors; RH and T do not need to be taken into account when studying the CO2 concentration over a larger interval, as long as the conditions are not condensing.
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Benhadia, Abrehem M. A. "Evaluation of the critical parameters and polymeric coat performance in compressed multiparticulate systems." Thesis, University of Bradford, 2019. http://hdl.handle.net/10454/17459.
Full textAbstract:
Compression of coated pellets is a practical alternative to capsule filling. The
current practice is to add cushioning agents to minimize the stress on the
coated pellets. Cushioning agents however add bulkiness and reduce the
overall drug loading capacity. In this study, we investigated the performance
of compressed coated pellets with no cushioning agent to evaluate the
feasibility of predicting the coat behaviour using thermo-mechanical and
rheological analysis techniques. Different coating formulations were made of
ethyl cellulose (EC) as a coating polymer and two different kinds of additives
were incorporated into the polymeric coating solution. Triethyl Citrate (TEC)
and Polyethylene glycol 400(PEG400) were used as plasticizers at different
levels to the coating formulations (10%, 20%, 30%). Thermal, mechanical
and rheological measurements of the coating film formulations were
achieved to investigate the effect of plasticizers. Thermal gravimetric
analysis results (TGA) showed higher residual moisture content in films
plasticised with PEG 400 compared to their TEC counterparts. Differential
Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and
Parallel Plate Shear Rheometer (PPSR) were used to study the influence of
the level and type of plasticisers incorporated in coating film formulation on
the performance of the coating film. In this study, both DSC and DMA were used to investigate the Tg for each film coating formulation in order to
evaluate the effect of the additives. In general DMA results for the Tg value
of the films were always higher by 10-20% than those measured by the DSC.
Furthermore, clamp size and the frequency of the oscillation have an
influence on the evaluation of Tg. Complex viscosity for different coating film
formulations revealed that the shear hinning gradient changes with
temperature and plasticiser type and concentration. The value of complex
viscosity from DMA and PPSR exhibits power law behaviour. The rheological
moduli were indirectly affected by the level of plasticiser. There was a
discrepancy between the complex viscosity results obtained from both DMA
and PPSR at similar temperature but they follow the same trend. The non
plasticized polymer showed a 10 time higher complex viscosity values when
measured by DMA over that measured by PPSR. The difference was smaller
in plasticized films but it was not consistent. Therefore a consistent
coefficient to correlate the DMA and PPSR couldn’t be accurately determined
Coated pellets were compressed and key process parameters were
evaluated. The obtained results revealed that the coating thickness has a
significant effect on the release profile of the final products. It was found that
by increasing the coating film thickness, the percentage released decreased.
Also the compression force has lower influence on the drug release profile,
while the dwell time has very low effect on the percentage release from the
final products. Optimum release profile was obtained at a coating level of 5.5%
w/w and a compression force of 4700N
In conclusion, the elasticity of the plasticised EC films in this study meant
that the internal stress is not dissipated during compression and the dwell time range that was used in this experiment. Increasing the thickness
therefore was necessary to enhance the strength of the film and avoid
cracking. The mechanical and rheological profiling was helpful therefore to
understand the behaviour of the coated pellets and predict the film properties
at various steps of the process of coating and compression (i.e., various
shear rate regimes). Experimental design approach to studying the key
process and formulation parameters helped identify the optimum values for
the process.
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Ziegler, Silvio. "New current sensing solutions for low-cost high-power-density digitally controlled power converters." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2010.0077.
Full textAbstract:
[Truncated abstract] This thesis studies current sensing techniques that are designed to meet the requirements for the next generation of power converters. Power converters are often standardised, so that they can be replaced with a model from another manufacturer without an expensive system redesign. For this reason, the power converter market is highly competitive and relies on cutting-edge technology, which increases power conversion efficiency and power density. High power density and conversion efficiency reduce the system cost, and thus make the power converter more attractive to the customer. Current sensing is a vital task in power converters, where the current information is required for monitoring and control purposes. In order to achieve the above-mentioned goals, existing current sensing techniques have to be improved in terms of cost, power loss and size. Simultaneously, current information needs to be increasingly available in digital form to enable digital control, and to allow the digital transmission of the current information to a centralised monitoring and control unit. All this requires the output signal of a particular current sensing technique to be acquired by an analogue-to-digital converter, and thus the output voltage of the current sensor has to be sufficiently large. This thesis thoroughly reviews contemporary current sensing techniques and identifies suitable techniques that have the potential to meet the performance requirements of the next-generation of power converters. After the review chapter, three novel current sensing techniques are proposed and investigated: 1) The usefulness of the resistive voltage drop across a copper trace, which carries the current to be measured, to detect electrical current is evaluated. Simulations and experiments confirm that this inherently lossless technique can measure high currents at reasonable measurement bandwidth, good accuracy and low cost if the sense wires are connected properly. 2) Based on the mutual inductance theory found during the investigation of the copper trace current sense method, a modification of the well-known lossless inductor current sense method is proposed and analysed. This modification involves the use of a coupled sense winding that significantly improves the frequency response. Hence, it becomes possible to accurately monitor the output current of a power converter with the benefits of being lossless, exhibiting good sensitivity and having small size. 3) A transformer based DC current sense method is developed especially for digitally controlled power converters. This method provides high accuracy, large bandwidth, electrical isolation and very low thermal drift. Overall, it achieves better performance than many contemporary available Hall Effect sensors. At the same time, the cost of this current sensor is significantly lower than that of Hall Effect current sensors. A patent application has been submitted. .... The current sensing techniques have been studied by theory, hardware experiments and simulations. In addition, the suitability of the detection techniques for mass production has been considered in order to access the ability to provide systems at low-cost.
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Machado, Maria Angélica. "Global climatic changes, a cse study of air temperature variation and its impacts in the municipal district of Ubatuba, north coasth of São Paulo." Universidade de Taubaté, 2009. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=239.
Full textAbstract:
This work aims to provide a forecast of the air temperature for future climatic scenarios with an estimation of sea level rise and its environmental consequences in the municipality of Ubatuba. The adopted methodology is based on the use of air temperature simulated data from HadCM3 Model from Hadley Center from United Kingdom (from 2000 until 2099) considering two scenarios used by the Intergovernmental Panel on Climate Changes, namely A2 scenario (pessimistic) and B1 scenario (optimistic). The estimates of elevation of the sea level of 124 and 268 cm for 2050 and 2100, respectively was realized based on tidal observations in Ubatuba in the period from 1954 up to 1993. As result it is estimated an increase of the air temperature by 5.3 ( 3.0)C for the A2 scenarious and by 3.4 ( 3.0)C to B1 case. Using data of topographyc profiles of 11 beaches in the region, it has been concluded that all these beaches will disappear by 2050.Este trabalho tem por objetivo apresentar uma previsão da temperatura do ar em cenários climáticos futuros, com uma estimativa da elevação do nível do mar e suas conseqüências ambientais no município de Ubatuba. A metodologia adotada esta baseada na utilização de dados de temperatura do ar simulados pelo modelo HadCM3 do Hadley Center do Reino Unido (no período de 2000 a 2099), considerando dois cenários utilizados pelo Painel Intergovernamental de Mudanças Climáticas, a saber: cenário A2 (pessimista) e cenário B1 (otimista). As estimativas de aumento do nível do mar foram realizadas a partir de registros maregráficos de Ubatuba (de 1954 a 1993). Como resultado estima-se um aumento na temperatura média global de 5,3 ( 3,0)C para o cenário A2 e de 3,4 ( 3,0)C para o cenário B1 e uma estimativa de elevação do nível médio do mar de 124 e de 268 cm para os anos de 2050 e 2100, respectivamente. Usando-se dados de perfis topográficos de 11 praias insulares na região, conclui-se que estas praias desaparecerão a partir de 2050.
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Khanzada, Laraib Sarfraz [Verfasser], Rainer [Akademischer Betreuer] Hock, and Christoph J. [Gutachter] Brabec. "Low cost, abundant, non-toxic and low temperature solution processable inorganic semiconductors for photovoltaic applications / Laraib Sarfraz Khanzada ; Gutachter: Christoph J. Brabec ; Betreuer: Rainer Hock." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2018. http://d-nb.info/1172972427/34.
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Serralheiro, Ana Sofia Ramos. "Ecologia da germinação de sementes de espécies de charcos temporários mediterrânicos: implicações para a conservação." Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/18396.
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Devido às inúmeras ameaças que se fazem sentir sobre este habitat protegido – os
charcos temporários mediterrânicos (CTM) – a recoleção de germoplasma e os
estudos da reprodução podem contribuir para a sua preservação. As espécies
características dos CTM germinam em condições hidrológicas e climatológicas muito
variáveis de ano para ano e que se verificam apenas durante um período de tempo
curto. No entanto, o conhecimento sobre a ecologia da germinação das suas espécies
mais emblemáticas é escasso, em particular após um período de conservação ex situ,
durante o qual pode ocorrer dormência ou diminuição da sua viabilidade. É por isso
crucial obter este conhecimento de modo a poder planificar com sucesso a utilização
destas sementes para efeitos de recuperação de CTM.
Os principais objetivos deste trabalho são determinar qual a viabilidade das sementes
recolhidas e quais as condições de luz e temperatura mais adequadas à maximização
da germinação de cada uma das espécies estudadas. A experimentação foi efetuada
em ambiente controlado – câmara de germinação sob um fotoperíodo de 12h e
temperaturas constantes de 15ºC, a simular as condições de temperatura que se
verificam no centro do charco no outono e primavera, ou alternadas de 20 e 10ºC, a
simular as condições de temperatura que se verificam na periferia do charco nos
períodos diurno e noturno, respetivamente. Os resultados obtidos permitiram concluir
que a viabilidade inicial dos lotes de semente colhida era elevada o que os torna
adequados para a conservação ex situ. De um modo geral, a luz favoreceu a
germinação das sementes, tal como a temperatura alternada; Germination ecology of seeds from species of Mediterranean
temporary ponds – implications for conservation
Abstract:
Considering the numerous threats to the protected habitat Mediterranean Temporary
Ponds (MTP), collecting germplasm and performing reproduction studies could
contribute to its preservation. The characteristics species of MTP germinate in variable
hydrological and climatological conditions each year during a short period of time.
However, knowledge about the ecology of germination of its most emblematic species
is scarce, particularly after a period of ex situ conservation, during which dormancy or
decreased viability may occur. It is therefore crucial to acquire this knowledge in order
to successfully plan the use of these seeds in MTP recovery.
The main objectives of this study were to determine the viability of the collected seeds
and which were the light and temperature conditions best suited to maximize the
germination of each species studied. The experimentation was performed in a
controlled environment - a growth chamber under a photoperiod of 12 hours and
constant temperatures of 15ºC to simulate the temperature conditions of the pond
center) or alternating temperature of 20 and 10°C to simulate the temperature
conditions on the margins of the pond, during day and night, respectively. The results
allowed us to conclude that the initial viability of the collected seed batches was high
and thus adequate to ex situ conservation. We found that in general light enhanced
seed germination and that alternating temperature also favored seed germination.
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Southon, Michael Carl. "Performance and cost evaluation to inform the design and implementation of Organic Rankine Cycles in New Zealand." Thesis, University of Canterbury. Mechanical Engineering, 2015. http://hdl.handle.net/10092/10728.
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The aim of this thesis is to evaluate ORC systems and technologies from an energy and economic perspective. ORC systems are a growing renewable electricity generation technology, but New Zealand has limited local skills and expertise for identifying ORC resource opportunities and subsequently developing suitable technologies at low cost. For this reason, this thesis researches ORC technology, resource types, and international development, with the aim to determine guidelines for how to cost-effectively develop ORC systems, and to make recommendations applicable to furthering their development within a New Zealand context. This thesis first uses two surveys, one of commercial ORC installations, and a second of economic evaluations of ORC systems in literature, to determine what resources and economic scenarios are supportive of commercial development. It is found that geothermal resources provide the largest share of ORC capacity, with biomass and waste-heat recovery (WHR) being developed more recently. The surveys also found that countries with high electricity prices or policy interventions have developed a wider range of resources using ORC systems. This thesis then undertakes an EROI evaluation of ORC electricity generation systems using a combination of top-down and process based methodologies. Various heat sources; geothermal, biomass, solar, and waste heat are evaluated in order to determine how the utilised resource can affect energy profitability. A wide range of EROIstnd values, from 3.4 – 22.7 are found, with solar resources offering the lowest EROIs, and geothermal systems the highest. Higher still EROI values are found to be obtainable with longer system lifetimes, especially for WHR systems. Specific engineering aspects of ORC design and technology such as high-side pressure, heat storage, modularity, superheating, pinch-point temperature difference, and turbine efficiency are evaluated in terms of economic performance, and a variety of general conclusions are made about each. It is found that total system thermo-economic optimisation may not lead to the highest possible EROI, depending on the objective function. Lastly, the effects of past and potential future changes to the markets and economies surrounding ORCs are explored, including the New Zealand electricity spot price, steel and aluminium prices, subsidies, and climate policy. Of the subsidy types explored, it is found that directly subsidising ORC system capital has the greatest effect on the economic performance of ORC systems, as measured by common metrics. In conclusion, this thesis finds that ORC systems have a limited applicability to New Zealand’s electricity market under current economic conditions outside of geothermal and off-grid generation, but changes to these conditions could potentially make their development more viable. The author recommends that favourable resources should be developed using systems that provide high efficiencies, beyond what might provide the best economic performance, in order to increase EROI, and reduce the future need for costly investments into increasingly less favourable resources.
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McEwan, Anthony Graham. "The effect of elevated temperature on the nutrient requirements of rainbow trout, Salmo gairdneri (Pisces : Salmonidae) and the development of "least cost" feeds for trout production in South Africa." Thesis, Rhodes University, 1988. http://hdl.handle.net/10962/6606.
Full textAbstract:
A review of trout metabolism, ingested energetic pathways, essential dietary nutrient requirements and the effect of water temperature on trout physiology identified the need to determine the effect of elevated temperatures (>18oC) on the nutrient requirements of rainbow trout. This review led to the hypothesis that as the temperature exceeds the optimum the growth potential of trout decreases with a theoretical concomitant decrease in the protein requirement. However, the increased metabolic rates of the fish should be reflected by an increased demand for lipids. The experiments designed to test this hypothesis revealed that at temperatures in excess of 18 oC the protein requirement for small (4.5g) and larger (>25g) juvenile rainbow trout are 40 and 35% respectively. This represents a decrease of 10% for the small juveniles and no change for larger juveniles compared to their requirements at optimum temperatures. The lipid requirements for the small as well as the larger juveniles increased by approximately 5 percent, to between 20 and 23 percent, compared to the requirement at optimum temperatures. Consequently the hypothesis was accepted. A review of practical diet formulation is presented along with a description of the experiments conducted to test several "least cost" diets under South African conditions. Recommendations that winter and summer diets be formulated and that the trout producers manufacture their own feeds are made. The most appropriate diet formulated and tested effected a 21 to 29.9 percent saving compared to the currently available feeds in South Africa.
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Callegari, Andrea. "Produzione e caratterizzazione di acqua attivata mediante plasmi freddi atmosferici per applicazioni in agricoltura." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19708/.
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This thesis is concerned with the production and characterization of PAW and its application to promote seeds germination. Two low temperature plasma devices operating at atmospheric pressure will be compared: an RF capacitively coupled source, COST Reference Microplasma Jet and another jet based on a DBD configuration, thus named DBD jet.
After plasma treatments, variations of physicochemical properties induced in PAW, such as dissolved oxygen content, electrical conductivity, pH and concentrations of the main reactive species, were measured.
Finally, the effects of the resulting solutions in enhancing germination were investigated, through the use of these liquids for the imbibition of two varieties of radish seeds (Raphanus sativus var. Sativus), chosen as model seeds.
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Chen, Minyong. "Deciphering the Role of YidC in Bacterial Membrane Protein Insertion." The Ohio State University, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=osu1039101039.
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Rêgo, Márlison de Sá. "DESENVOLVIMENTO E VALIDAÇÃO DE SISTEMAS DE MONITORAMENTO DE BAIXO CUSTO DE TEMPERATURA E UMIDADE RELATIVA DO AR." Universidade Federal de Santa Maria, 2016. http://repositorio.ufsm.br/handle/1/7654.
Full textAbstract:
From the perspective of optimizing the planning, management and management of water resources in the national context the hydrometeorological monitoring systems have gone through the process of technological innovation. Increased monitoring of potential for reduced costs and improved quality of monitored data motivate this field of research. Starting from the importance of the variables of temperature and relative humidity among the variables monitored, this paper proposes the development of three hardware systems and software based on an open platform, which measure these values accurately from three sensors low cost, RHT01, RHT02 and RHT03 available in the market from the year 2005. These sensors are part of the advancement of sensor lines, newly created, polymer and semiconductor oxides. The technological base of each system is the microcontroller "arduino rev. 3 ", which he managed an electronic circuit capable of collecting and storing data from hydro-meteorological variables, in a flash memory device (sd card). Then, in order to check the reliability on the operation, each system was subjected to three data collection tests, at three different sites operating simultaneously with conventional systems used by the Micrometeorology Laboratory of UFSM (LMMET/UFSM). Local tests are situated in the municipality of Santa Maria, in the state of Rio Grande do Sul, Brazil. The microclimate conditions were different among trials due to location. The first test was performed on the terrace of the INPE-UFSM facilities, the second test in micrometeorology Laboratory of UFSM and the third in a rural area of central campus of UFSM, characterized by the pampa biome, which is located a network monitoring tower micro-sulfux. The collections occurred during the months from April to June, representing the final step of the fall season and the beginning of winter in 2015. The first trial lasted eleven days, the second and third Thirteen Eleven. The time discretization of the collections was a minute. With the data collected was carried out comparative analysis of inexpensive and conventional systems by graphic systems for analysis, descriptive statistics, and statistics such as Pearson correlation coefficients, ANOVA and Tukey test. With determination coefficient values (R2) higher than 0.90 in all tests and no significant difference between low-cost sensors and analyzed conventional systems, with only one exception, the results indicated the feasibility of using these sensors to generate Data medium temperature and relative humidity for a minimum time interval from generation 1 minute, 15 minutes, 30 minutes and 1 hour. The results also indicated the possibility of further quantitative research on the influence of the sensors under the measured data.Na perspectiva de otimizar o planejamento, manejo e gestão dos recursos hídricos no contexto nacional os sistemas de monitoramento hidrometeorológico tem passado pelo processo de inovação tecnológica. O aumento do potencial de monitoramento pela diminuição dos custos e a melhora na qualidade dos dados monitorados motivam esse campo de pesquisa. Partindo-se da relevância das variáveis de temperatura e umidade relativa do ar dentre as variáveis monitoradas, o presente trabalho propõe o desenvolvimento de três sistemas de hardware e software baseados em uma plataforma livre, que meçam essas grandezas com precisão a partir de três sensores de baixo custo, RHT01, RHT02 e RHT03, disponíveis no mercado a partir do ano de 2005. Estes sensores fazem parte do avanço das linhas de sensores, recém-criadas, de polímeros e óxidos semicondutores. A base tecnológica de cada sistema foi o microcontrolador arduino rev. 3 , o qual gerenciou um circuito eletrônico capaz de coletar e armazenar dados das variáveis hidrometeorológicas, em um dispositivo de memória flash ( sd card ). Em seguida, com o objetivo de verificar a confiabilidade quanto ao funcionamento, cada sistema foi submetido a três testes de coleta de dados, em três locais diferentes operando em simultâneo com sistemas convencionais utilizados pelo Laboratório de Micrometeorologia da UFSM (LMMET/UFSM). Os locais dos testes estão situados no município de Santa Maria, no Estado do Rio Grande do Sul, Brasil. As condições de microclima entre os testes eram diferentes em virtude do local. O primeiro teste foi realizado no terraço das instalações do INPE-UFSM, o segundo teste no laboratório de micrometeorologia da UFSM e o terceiro em uma área rural do campus central da UFSM, caracterizada pelo bioma pampa, onde fica localizada uma torre de monitoramento da rede micro-sulfux. As coletas ocorreram durante os meses de abril a junho, correspondendo a etapa final da estação de outono e início do inverno no ano de 2015. O primeiro teste durou onze dias, o segundo treze e o terceiro onze. A discretização temporal das coletas foi de um minuto. Com os dados coletados realizou-se análise comparativa dos sistemas de baixo custo e os sistemas convencionais mediante a análise de gráficos, medidas descritivas, e de estatísticas tais como a correlação linear de Pearson, análise de variância e teste Tukey. Com valores de coeficiente de determinação (R2) superiores a 0,90 em todos os testes e não havendo diferença significativa entre os sensores de baixo custo analisados e o sistemas convencional, com apenas uma única exceção, os resultados indicaram a viabilidade do uso destes sensores para geração de dados médios de temperatura e umidade relativa do ar para intervalo de tempo mínimo de geração de 1 minuto, 15 minutos, 30 minutos e 1 hora. Os resultados também indicaram a possibilidade de pesquisas quantitativas posteriores sobre a influência do abrigo dos sensores nos dados mensurados.
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Manikonda, Nikhil. "Performance of Deep Geothermal Energy Systems." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23219.
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Geothermal energy is an important source of clean and renewable energy. This project deals with the study of deep geothermal power plants for the generation of electricity. The design involves the extraction of heat from the Earth and its conversion into electricity. This is performed by allowing fluid deep into the Earth where it gets heated due to the surrounding rock. The fluid gets vaporized and returns to the surface in a heat pipe. Finally, the energy of the fluid is converted into electricity using turbine or organic rankine cycle (ORC). The main feature of the system is the employment of side channels to increase the amount of thermal energy extracted. A finite difference computer model is developed to solve the heat transport equation. The numerical model was employed to evaluate the performance of the design. The major goal was to optimize the output power as a function of parameters such as thermal diffusivity of the rock, depth of the main well, number and length of lateral channels. The sustainable lifetime of the system for a target output power of 2 MW has been calculated for deep geothermal systems with drilling depths of 8000 and 10000 meters, and a financial analysis has been performed to evaluate the economic feasibility of the system for a practical range of geothermal parameters. Results show promising an outlook for deep geothermal systems for practical applications.
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Benoist, Romain. "Bases comportementales, physiologiques et génétiques du succès reproducteur d'un hyménoptère parasitoïde The Cotesia sesamiae story: insight into host-range evolution in a Hymenoptera parasitoid and implication for its use in biological control programs Low-cost automatic temperature monitoring system with alerts for laboratory rearing units." Thesis, Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=http://theses-intra.upmc.fr/modules/resources/download/theses/2019SORUS584.pdf.
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Etudier l’aptitude d’insectes parasitoïdes à se reproduire dans de nouveaux hôtes est important pour comprendre les mécanismes d’adaptation dans un contexte de lutte biologique. Cotesia typhae est un parasitoïde africain spécialisé sur le lépidoptère Sesamia nonagrioides et est un agent de lutte biologique potentiel contre ce ravageur du maïs. C. typhae appartient à un groupe d’espèces possédant un virus endosymbiotique injecté dans l’hôte lors de la ponte et contribuant à la virulence du parasitoïde. J’ai pu montrer que deux souches de C. typhae diffèrent par leur nombre de descendants et par leur virulence envers une population française de S. nonagrioides, représentant un nouvel hôte. Afin d’identifier les gènes responsables de ces variations une recherche de QTL a été entreprise (Quantitative Trait Loci). Nous avons établi une carte génétique de C. typhae, identifié quatre QTL et dressé une liste de gènes candidats. Pour expliquer la différence de virulence et du nombre de descendants, les quantités d’œufs et de virus injectés au cours de pontes successives ont été estimées. Ces expériences ont montré 1/ que les deux souches ne répartissent pas leurs œufs de la même manière entre les hôtes, 2/ que la quantité de virus injectés n’est pas corrélée à la virulence. Pour comprendre l’origine évolutive de la différence de virulence, ce trait a été estimé sur les populations hôtes naturelles. Les résultats suggèrent que l’adaptation locale pourrait être à l’origine de la pré-adaptation d’une des souches à l’hôte français. Ce travail a permis également de bien caractériser le succès reproducteur de C. typhae, essentiel pour son utilisation en lutte biologiqueStudying the ability of insect parasitoids to reproduce in novel hosts is important to understand adaptive mechanisms at play when they are used for biological control. Cotesia typhae is an African parasitoid specialized on the Lepidoptera Sesamia nonagrioides and it is a potential biological control agent against this maize pest. C. typhae belongs to a group of species harboring a symbiotic virus which is injected in the host during oviposition and which contributes to the parasitoid virulence. I have found out that two strains of C. typhae differed in their offspring number and in their virulence against a French population of S. nonagrioides, which represents a new host. A QTL analysis (Quantitative Trait Loci) has been done to identify genes involved in these variations. We have built a genetic map of C. typhae, identified four QTL and listed candidate genes. To explain the difference of virulence and offspring number, numbers of eggs and viral particles injected during successive ovipositions have been estimated. These experiments have shown that 1/ the two strains have different patterns of egg allocation among the successive hosts parasitized, 2/ the quantity of injected viral particles is not correlated to virulence. To understand to evolutionary origin of the virulence variation, this trait has been estimated for the natural host populations. The results suggest that local adaptation could explain the better pre-adaptation of one C. typhae strain to the French host population. This work also allowed an in-depth characterization of the parasitoid reproductive success, essential for its use in biological control
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Lee, Jiwon. "Novel fabrication of Alloy 625 and MCrAlY bond coat by laser powder bed fusion and microstructure control A novel approach to the production of NiCrAlY bond coat onto IN625 superalloy by selective laser melting Influence of heat treatments on microstructure evolution and mechanical properties of Inconel 625 processed by laser powder bed fusion A new observation of strain-induced grain boundary serration and its underlying mechanism in a Ni–20Cr binary model alloy Heat treatments design for superior high-temperature tensile properties of Alloy 625 produced by selective laser melting High temperature oxidation of NiCrAlY coated Alloy 625 manufactured by selective laser melting." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0008.
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Dans cette étude, l'alliage 625 a été élaboré par l'une des méthodes de fabrication additive (AM) les plus couramment utilisées, la fusion laser sélective sur lit de poudre (L-PBF), et ses propriétés mécaniques ont été évaluées à différentes températures. L'alliage 625 fabriqué par L-PBF a montré une résistance élevée et un allongement à la rupture médiocre. Ainsi, des traitements thermiques ont été appliqués pour améliorer ses performances. Un traitement thermique de mise en solution à une température supérieure à 1000 °C a été appliquée à l'alliage L-PBF 625, ce qui a entraîné une recristallisation en raison de l’énergie stockée par le matériau attribuée à la forte densité de dislocations présentes dans l’alliage. Cette microstructure modifiée a montré une résistance satisfaisante lors des essais de traction à température ambiante (résistance plus élevée que l'alliage corroyé 625 et allongement supérieur à l'alliage L-PBF brut de fabrication). À l'étape suivante, l'alliage L-PBF 625 recristallisé a été soumis à un traitement thermique de Grain Boundary Serration (GBS, dentelure des joints de grains) pour améliorer ses propriétés mécaniques à haute température. Comme il s'agissait de la première tentative pour générer la GBS d'un alliage à haute teneur en Nb, il était d'abord important de comprendre le mécanisme GBS. Pour induire le GBS, il est nécessaire que les larges atomes de soluté se déplacent près des joints de grains (GB). Par conséquent, le traitement thermique GBS a été modifié pour être appliqué à l'alliage L-PBF 625. Le traitement thermique de GBS spécialement conçu a réussi à induire pour la première fois les motifs en zigzag des GB dentelés. Cet alliage GB-L-PBF dentelé 625 a montré des propriétés mécaniques améliorées à haute température en termes de ductilité accrue et d'élimination de l'effet de vieillissement dynamique (DSA). Pour améliorer davantage les propriétés à haute température de l'alliage L-PBF 625, un revêtement de liaison NiCrAlY a été nouvellement appliqué au substrat en alliage 625 par la même méthode (L-PBF) pour améliorer l'efficacité du processus de production et augmenter la résistance à l'oxydation/corrosion à haute température. Bien que leurs différentes propriétés thermiques aient conduit à de nombreux essais et erreurs dans la fabrication du matériau, les paramètres optimaux ont été définis et vérifiés pour évaluer le potentiel de commercialisation du procédé. La caractéristique de refusion du L-PBF a induit une bonne liaison entre le substrat et le revêtement, ce qui indique une bonne stabilité. Le comportement à l'oxydation de l'alliage 625 revêtu de NiCrAlY a été caractérisé par analyse thermo-gravimétrique (TGA) et des tests de chocs thermiques ; les résultats ont indiqué que le nouveau matériau avait une résistance à l'oxydation plus élevée que l'alliage 625 brut de fabrication. Par conséquent, le traitement thermique de GBS associé à un revêtement NiCrAlY efficace peut améliorer considérablement les propriétés mécaniques à haute température de l'alliage 625 fabriqué par L-PBFIn this study, Alloy 625 was fabricated by one of the most commonly used additive manufacturing (AM) methods, laser powder bed fusion (L-PBF), and its mechanical properties were evaluated at various temperatures. The L-PBF fabricated Alloy 625 showed high strength and relatively poor elongation. Thus, some heat treatments were applied to improve its performance. A solid-solution heat treatment with a temperature of more than 1000 °C was applied to the L-PBF Alloy 625, resulting in recrystallization because of high energy stored within the alloy attributed by high density of dislocations. This modified microstructure of the L-PBF Alloy 625 sample showed the required strength under tensile testing at room temperature (higher strength than wrought Alloy 625 and greater elongation than L-PBF as-built alloy). In view of enhancing mechanical properties at high temperature, a grain boundary serration (GBS) heat treatment was specifically designed for L-PBF Alloy 625. Because this was the first attempt to produce GBS in a high-Nb-content alloy, it was necessary to understand its mechanism first. To induce GBS, it is necessary for large solute atoms to move near the grain boundaries (GBs). Therefore, the GBS heat treatment was modified for application to the L-PBF Alloy 625. The specially designed GBS heat treatment successfully induced the zigzag patterns of serrated GBs for the first time. This GBS L-PBF Alloy 625 showed improved high-temperature mechanical properties in terms of increased ductility and elimination of the dynamic strain aging (DSA) effect at elevated temperatures. To further improve the high-temperature property of the L-PBF Alloy 625, NiCrAlY bond coat was applied to the Alloy 625 substrate by the same method (L-PBF) for the first time to improve the efficiency of the production process and increase the resistance to oxidation. Although their different thermal properties led to many trials and errors in the manufacturing of the material, the optimal parameters for applying NiCrAlY bond coat deposition by L-PBF were set and verified to assess the potential for the process to be commercialized. The remelting characteristic of L-PBF induced good metallurgical bonding between the substrate and coating, which indicates good stability. The oxidation behavior of the NiCrAlY-coated Alloy 625 was characterized by thermal gravimetric analysis (TGA) and thermal shock testing; the results indicated that the novel coated material had higher resistance to oxidation than bulk Alloy 625. Therefore, the GBS heat treatment together with efficient NiCrAlY coating can greatly improve the high-temperature mechanical properties of L-PBF manufactured Alloy 625
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Sewe, Maquins Odhiambo. "Towards Climate Based Early Warning and Response Systems for Malaria." Doctoral thesis, Umeå universitet, Epidemiologi och global hälsa, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-130169.
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Background: Great strides have been made in combating malaria, however, the indicators in sub Saharan Africa still do not show promise for elimination in the near future as malaria infections still result in high morbidity and mortality among children. The abundance of the malaria-transmitting mosquito vectors in these regions are driven by climate suitability. In order to achieve malaria elimination by 2030, strengthening of surveillance systems have been advocated. Based on malaria surveillance and climate monitoring, forecasting models may be developed for early warnings. Therefore, in this thesis, we strived to illustrate the use malaria surveillance and climate data for policy and decision making by assessing the association between weather variability (from ground and remote sensing sources) and malaria mortality, and by building malaria admission forecasting models. We further propose an economic framework for integrating forecasts into operational surveillance system for evidence based decisionmaking and resource allocation. Methods: The studies were based in Asembo, Gem and Karemo areas of the KEMRI/CDC Health and Demographic Surveillance System in Western Kenya. Lagged association of rainfall and temperature with malaria mortality was modeled using general additive models, while distributed lag non-linear models were used to explore relationship between remote sensing variables, land surface temperature(LST), normalized difference vegetation index(NDVI) and rainfall on weekly malaria mortality. General additive models, with and without boosting, were used to develop malaria admissions forecasting models for lead times one to three months. We developed a framework for incorporating forecast output into economic evaluation of response strategies at different lead times including uncertainties. The forecast output could either be an alert based on a threshold, or absolute predicted cases. In both situations, interventions at each lead time could be evaluated by the derived net benefit function and uncertainty incorporated by simulation. Results: We found that the environmental factors correlated with malaria mortality with varying latencies. In the first paper, where we used ground weather data, the effect of mean temperature was significant from lag of 9 weeks, with risks higher for mean temperatures above 250C. The effect of cumulative precipitation was delayed and began from 5 weeks. Weekly total rainfall of more than 120 mm resulted in increased risk for mortality. In the second paper, using remotely sensed data, the effect of precipitation was consistent in the three areas, with increasing effect with weekly total rainfall of over 40 mm, and then declined at 80 mm of weekly rainfall. NDVI below 0.4 increased the risk of malaria mortality, while day LST above 350C increased the risk of malaria mortality with shorter lags for high LST weeks. The lag effect of precipitation was more delayed for precipitation values below 20 mm starting at week 5 while shorter lag effect for higher precipitation weeks. The effect of higher NDVI values above 0.4 were more delayed and protective while shorter lag effect for NDVI below 0.4. For all the lead times, in the malaria admissions forecasting modelling in the third paper, the boosted regression models provided better prediction accuracy. The economic framework in the fourth paper presented a probability function of the net benefit of response measures, where the best response at particular lead time corresponded to the one with the highest probability, and absolute value, of a net benefit surplus. Conclusion: We have shown that lagged relationship between environmental variables and malaria health outcomes follow the expected biological mechanism, where presentation of cases follow the onset of specific weather conditions and climate variability. This relationship guided the development of predictive models showcased with the malaria admissions model. Further, we developed an economic framework connecting the forecasts to response measures in situations with considerable uncertainties. Thus, the thesis work has contributed to several important components of early warning systems including risk assessment; utilizing surveillance data for prediction; and a method to identifying cost-effective response strategies. We recommend economic evaluation becomes standard in implementation of early warning system to guide long-term sustainability of such health protection programs.
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Hallqvist, Karl. "Högtempererat borrhålslager för fjärrvärme." Thesis, Uppsala universitet, Naturresurser och hållbar utveckling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231586.
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The district heating load is seasonally dependent, with a low load during periods of high ambient temperature. Thermal energy storage (TES) has the potential to shift heating loads from winter to summer, thus reducing cost and environmental impact of District Heat production. In this study, a concept of high temperature borehole thermal energy storage (HT-BTES) together with a pellet heating plant for temperature boost, is presented and evaluated by its technical limitations, its ability to supply heat, its function within the district heating system, as well as its environmental impact and economic viability in Gothenburg, Sweden, a city with access to high quantities of waste heat. The concept has proven potentially environmentally friendly and potentially profitable if its design is balanced to achieve a good enough supply temperature from the HT-BTES. The size of the heat storage, the distance between boreholes and low borehole thermal resistance are key parameters to achieve high temperature. Profitability increases if a location with lower temperature demand, as well as risk of future shortage of supply, can be met. Feasibility also increases if existing pellet heating plant and district heating connection can be used and if lower rate of return on investment can be accepted. Access to HT-BTES in the district heating network enables greater flexibility and availability of production of District Heating, thereby facilitating readjustments to different strategies and policies. However, concerns for the durability of feasible borehole heat exchangers (BHE) exist in high temperature application.Värmebehovet är starkt säsongsberoende, med låg last under perioder av högre omgivningstemperatur och hög last under perioder av lägre omgivningstemperaturer. I Göteborg finns en stor mängd spillvärme tillgängligt för fjärrvärmeproduktion sommartid när behovet av värme är lågt. Tillgång till säsongsvärmelager möjliggör att fjärrvärmeproduktion flyttas från vinterhalvår till sommarhalvår, vilket kan ge såväl lönsamhet som miljönytta. Borrhålsvärmelager är ett förhållandevis billigt sätt att lagra värme, och innebär att berggrunden värms upp under sommaren genom att varmt vatten flödar i borrhål, för att under vinterhalvåret användas genom att låta kallt vatten flöda i borrhålen och värmas upp. I traditionella borrhålsvärmelager används ofta värmepump för att höja värmelagrets urladdade temperatur, men på grund av höga temperaturkrav för fjärrvärme kan kostnaden för värmepump bli hög. I denna rapport föreslås ett system för att klara av att nå höga temperaturer till en lägre kostnad. Systemet består av ett borrhålsvärmelager anpassat för högre temperaturer (HT-BTES) samt pelletspannor för att spetsa lagrets utgående fluid för att nå hög temperatur. Syftet med rapporten är att undersöka potentialen för detta HT-BTES-system med avseende på dess tekniska begränsningar, förmåga till fjärrvärmeleverans, konsekvenser för fjärrvärmesystemet, samt lönsamhet och miljöpåverkan. För att garantera att inlagringen av värme inte är så stor att priset för inlagrad värme ökar väsentligt, utgår inlagringen från hur mycket värme som kyls bort i fjärrvärmenätet sommartid. I verkligheten finns betydligt mer värme tillgänglig till låg kostnad. När HT-BTES-systemet producerar fjärrvärme, ersätts fjärrvärmeproduktion från andra produktionsenheter, förutsatt att HT-BTES-systemets rörliga kostnader är lägre. I Göteborg ersätts främst naturgas från kraftvärme, men också en del flis. Kostnadsbesparingen beror på differensen för total fjärrvärmeproduktionskostnad med och utan HT-BTES-systemet. Undersökningen visar att besparingen är större om HT-BTES-systemet placeras i ett område där det är möjligt att mata ut fjärrvärme med lägre temperatur. Om urladdning från HT-BTES kan ske med hög temperatur ökar också besparingen. Detta sker om lagrets volym ökar, om avståndet mellan borrhål minskar eller om värmeöverföringen mellan det flödande vattnet i borrhålen och berggrunden ökar. Dessa egenskaper för lagret leder också till minskade koldioxidutsläpp. Storleken på besparingen beror dock i hög grad på hur bränslepriser utvecklas i framtiden. Strategiska fördelar med HT-BTES-systemet inkluderar; minskad miljöpåverkan, robust system med lång teknisk livslängd (för delar av HT-BTES-systemet), samt att inlagring av värme kan ske från många olika produktionsenheter. Dessutom kan positiva bieffekter identifieras. Undersökningen visar att HT-BTES-systemet har god potential att ge lönsamhet och minskad miljöpåverkan, och att anläggning och drift av lagret kan ske utan omfattande lokal miljöpåverkan. Det har också visats att de geologiska förutsättningarna för HT-BTES är goda på många platser i Göteborg, även om lokala förhållanden kan skilja sig åt. För att nå lönsamhet för HT-BTES-systemet krävs en avvägning på utformning av lagret för att nå hög urladdad temperatur utan att investeringskostnaden blir för stor. Undersökningen visar att om anslutning av HT-BTES-systemet kan ske mot befintlig anslutningspunkt eller till befintlig värmepanna kan investeringskostnaden minska och därmed lönsamheten öka. Placering av HT-BTES-systemet i områden med risk för överföringsbegränsningar kan också minska behovet av att förstärka fjärrvärmenätet, och således bidra till att minska de kostnader som förstärkning av nätet innebär. Betydelsefulla parametrar för att nå lönsamhet för HT-BTES-system inkluderar dessutom kostnaden för inlagrad värme liksom vilket vinstkrav som kan accepteras. Tillgång till HT-BTES möjliggör ökad nyttjandegrad och flexibilitet för fjärrvärmeproduktionsenheter, och därmed ökad anpassningsmöjlighet till förändrade förutsättningar på värmemarknaden. Dock återstår att visa att komponenter som klarar de höga temperaturkraven kan tillverkas till acceptabel kostnad.
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Harmouch, Khaled. "Conception et réalisation d’un moteur piézoélectrique pour application automobile haute température." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC007.
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L’objectif de cette thèse est deconcevoir et de réaliser un moteurpiézoélectrique destiné à une application derécupération de chaleur du gaz d’échappement.Cette application nécessite un couplerelativement élevé, une compacité importante,une endurance thermique et un coût acceptable.Afin d’atteindre ce but, la conception du moteurpasse par le choix de son mode defonctionnement. Ce choix est fait en se basantsur des critères comme bas coût, fort couple etcompacité importante.Après la détermination de l’architecture dumoteur piézoélectrique, la modélisation estabordée. Le but du modèle est de calculer lescaractéristiques couple/vitesse connaissantses dimensions et ses matériaux, l’état desurface du contact, la précontrainte et la tensiond’alimentation.La modélisation développée était validée pardes mesures expérimentales.Dans la dernière partie, le moteur dimensionnéest réalisé et testé. Son comportementdynamique et ces caractéristiquescouple/vitesse étaient mesurés. A l’exceptiondu couple à l’arrêt et celui de blocage, toutes lesperformances requises par l’application étaientremplies.Finalement, les résultats de modèle sontcomparés aux mesures faites sur le prototype.Le comportement dynamique était bienreproduit par la modélisation. Néanmoins, uneimprécision du calcul des déplacements dustator était constatée. Cela implique uneimprécision du calcul des caractéristiquesmoteur. Il s’avère que cette imprécision est liéeà l’absence du coefficient d’amortissement decontactThe goal of this thesis is to designand build a piezoelectric motor for an exhaustgas heat recovery application. This applicationrequires relatively high torque, highcompactness, thermal endurance and acceptablecost.In order to achieve this goal, the design of theengine passes by the choice of its mode ofoperation. This choice is made based on criteriasuch as low cost, high torque and compactness.After the determination of the architecture ofthe piezoelectric motor, the modelling isaddressed. The purpose of the model is tocompute the torque/speed characteristicsknowing the motor dimensions and materials,the surface state of the contact, the precompressionforce and the supply voltage.The modeling developed was validated byexperimental measurements.In the last part, the motor is build and tested. Itsdynamic behavior and torque/speedcharacteristics were measured. With theexception of the peak and blocking torque, allthe performances required by the applicationwere fulfilled.Finally, the model results are compared to themeasurements done on the prototype. Thedynamic behavior is well predicted by themodel. However, the model is not able tocompute accurately the stator displacements.This implies inaccuracy in the motorcharacteristics computation. It turns out thatthey are related to the absence of the coefficientof contact damping