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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
741

Chladová odolnost horských a nížinných motýlů / Cold tolerance of mountain and lowland butterflies

VRBA, Pavel January 2015 (has links)
The thesis deals with ecophysiology of overwintering larvae of two butterfly genera, Colias and Erebia. It focuses on identification of supercooling point, survival of various low temperature regimes and composition of cryoprotective substances. Results are presented in the context of distributional limits of individual species, their habitat requirements and their potential endangerment due to environmental and habitat changes.
742

Prédétermination des hauteurs de départ d'avalanches. Modélisation combinée statistique-mécanique / Evaluation of avalanche release depths. Combined statistical-mechanical modeling

Gaume, Johan 30 October 2012 (has links)
La prédétermination de la hauteur de départ des avalanches représente un défi majeur pour l'évaluation du risque en montagne. Cette hauteur constitue en effet un ingrédient d'entrée important des procédures de zonage et de cartographie du risque. Dans cette thèse, nous présentons un formalisme rigoureux dans lequel les distributions de hauteur de départ d'avalanche sont exprimées à travers un couplage des facteurs mécaniques et météorologiques. Le critère de stabilité du système plaque - couche fragile est étudié en utilisant une analyse mécanique par éléments finis prenant en compte l'hétérogénéité spatiale des propriétés mécaniques. Considérant qu'une avalanche ne peut se produire que si la hauteur de chute de neige dépasse une hauteur critique correspondant au critère de stabilité, les distributions de hauteur de départ obtenues à partir du modèle mécanique sont couplées avec la distribution des chutes de neige extrêmes sur 3 jours. Nous montrons que ce modèle couplé est capable de reproduire des données de terrain de 369 avalanches naturelles de plaque à La Plagne (France). Non seulement la queue de la distribution en loi puissance, correspondant à des épaisseurs de plaque élevées, mais aussi le corps de la distribution pour les plaques moins épaisses, sont bien reproduits par le modèle. Les avalanches petites à moyennes semblent être essentiellement contrôlées par la mécanique, tandis que les grosses avalanches et l'exposant de la loi puissance associé, sont influencés par un couplage mécanique - météorologique fort. Par ailleurs, nous démontrons que la distribution obtenue est fortement dépendante de l'espace, et, en utilisant les processus max-stables permettant une interpolation spatiale rigoureuse, notre modèle couplé est utilisé pour obtenir des cartes de hauteur de départ d'avalanche pour différentes périodes de retour sur l'ensemble des Alpes françaises. / The evaluation of avalanche release depth distributions represents a major challenge for hazard management in mountaineous regions. This depth constitutes an important input ingredient of hazard mapping procedures. This PhD thesis presents a rigorous formalism in which these distributions are expressed through a coupling of mechanical and meteorological factors. The stability criterion of a layered snowpack is investigated using a finite-element analysis accounting for the spatial heterogeneity of weak-layer mechanical properties. Considering that an avalanche can occur only if the snowfall depth exceeds a critical value corresponding to a stability criterion, release depth distributions obtained from the mechanical model are coupled with the distribution of 3-day extreme snowfalls. We show that this coupled model is able to reproduce field data from 369 natural slab avalanches in La Plagne (France). Not only the power-law tail of the distribution, corresponding to large slab depths, but also the core of the distribution for shallow slab depths, are well represented. Small to medium-sized avalanches appear to be controlled mainly by mechanics, whereas large avalanches and the associated power-law exponent, are influenced by a strong mechanical-meteorological coupling. Finally, we demonstrate that the obtained distribution is strongly space dependent, and, using max-stables processes allowing a rigorous spatial interpolation, our coupled model is used to obtain release depth maps for given return periods in the whole French Alps.
743

Live-work units in subarctic climate as a part of sustainable city development : A design proposal

Ohls, Ingemar January 2018 (has links)
Today there is a wish from building entrepreneurs to be able to have other activities than traditional commercial areas on the street level in the residential housing while keeping the open store front windows facade. Another challenge today in development of cities are partially to maintain a socially sustainable city. A mix of housing,commercial, entertainment, and services make the area become more attractive to both men and women, entrepreneurship and civil society. By mixing the use there is a possibility to reduce segregation and strengthen a city’s capacity to build unity; social development. Live-work units can meet both these demands. The purpose of this master thesis is to illustrate how so called live-work units could be organized in a block in an urban environment. Live-work units are a new phenomenon in Sweden and, therefore, this study partially focuses on describing this type of living and its special requirements. A methodology is proposed for identifying if a location is suitable for live-work units and for what type of units; furthermore, parameters and regulations affecting the usage of live-work units are described and a method for design is proposed.
744

Modern Day Fairy Tales : A comparative study between Amy Plum's Die for Me and the Western Fairy Tale Tradition

Persson Penzer, Anna January 2015 (has links)
No description available.
745

Subsurface fluxes of mass and energy at the accumulation zone of Lomonosovfonna ice cap, Svalbard

Marchenko, Sergey January 2018 (has links)
Glaciers cover ca 10% of the Earth's land and are found in the high altitudes and latitudes. They are important components of environmental systems due to the multiple feedbacks linking them with the atmosphere, hydrosphere and periglacial landscapes. The cold sloping surfaces of glaciers change the patterns of atmospheric circulation at different scales and at the same time glaciers are largely controlled by climate. They are commonly used as climatic archives for reconstruction of the past environmental changes based on evidences from the areas affected by glaciation at the moment and in the past. Glaciers are the largest fresh-water reservoirs on our planet and runoff thereof significantly affects the global sea level and life in glaciated catchments. However, melt- and rain-induced runoff from glaciers greatly depends on the subsurface conditions which thus need to be taken into account, particularly in a changing climate. This thesis focuses on the processes of subsurface mass and energy exchange in the accumulation zones of glaciers, which are largely driven by the climate at the surface. Results are largely based on empirical data from Lomonosovfonna ice cap, Svalbard, collected during field campaigns in 2012-2017. Observations of subsurface density and stratigraphy using shallow cores, video records from boreholes and radar surveys returned detailed descriptions of the snow and firn layering. The subsurface temperature data collected using multiple thermistor strings provided insights into several subsurface processes. The temperature values measured during three summer seasons were used to constrain the suggested parameterization of deep preferential water flow through snow and firn. The part of data recorded during the cold seasons was employed for an inverse modelling exercise resulting in optimized values of effective thermal conductivity of the subsurface profile. These results are then used to compute the subsurface water content by comparing the simulated and measured rates of freezing front propagation after the melt season in 2014. The field observations and quantitative estimates provide further empirical evidences of preferential water flow in snow/firn packs at glaciers. Results presented in the thesis call for implementation of description of the process in layered models simulating the subsurface fluxes of energy and mass at glaciers. This will result in a better understanding of glacier response to the past and future climatic changes and more accurate estimates of glacier runoff. / Stability and Variations of Arctic Land Ice (SVALI)
746

Snökyla för is och komfort : Möjligheter att använda snö för komfortkyla och isproduktion vid Rocklundas idrottsarenor

Vera Ibanez, Anatole January 2017 (has links)
The idea of snow cooling in this case is to save snow from winter to summer and to use it for air conditioning and for saving energy in the production of ice in hockey arenas. Today in Sweden, snow power on a large scale is used only on one place, the hospital in Sundsvall. There you’ll find a pond with 70 000 m3 of snow. The melt water in the pond is heated up while cooling down warm air from the hospital, before circulating back to the pond where it regains a low temperature passing through the snow. The idea was to examine the possibility to use such a system in Västerås, at the multiple sports arenas at Rocklunda, partly for air conditioning and partly for ice production. This work was made possible through gathering information on snow storage and on the Sundsvall snow cooling plant, by interviewing people with insight in the Sundsvall hospital and Rocklunda sports arenas and by calculating the electricity consumption, necessary amount of snow and making an LCC-analysis. For air conditioning the melt water would be used like in Sundsvall but for ice production the melt water would be used for condensing the cooling media in the heat pump at a lower temperature then it would do while cooling with air or river water during summer. Annual electricity savings of 120 and 154 MWh for the arenas were made for 2016 and 2017 when using the snow for ice production. For the air conditioning the saving were estimated to around 55 MWh per year. A snow dispatch hatch in one of the hockey arenas made an alternative to a full-scale snow cooling system. Using this hatch for temporal snow power could save up to 62 MWh per year when used for ice production and 38 MWh when used for air conditioning. The estimated costs for construction of said system proved to be too expensive for making a full-scale snow power system a reality. For ice production a storage of 103 000 m3 of snow was needed which made for a result of -57 MSEK in the LCC-analysis. For the air conditioning alone, a storage of 6 000 m3 was needed which made for a result of -4.2 MSEK. The snow dispose hatch, even without the need of snow storage, resulted in -5.9 MSEK for ice production and -1.6 MSEK for air conditioning. With more thoroughly estimations of the investment costs, together with global warming and thus bigger potential for saving energy, this might be a promising investment in the future.
747

在薩爾瓦多設立雪花冰舖之商業企畫書 / Business plan for a shaved ice shop in el salvador

賈美荷, Gamero, Maria Unknown Date (has links)
This business plan has been developed to determinate the feasibility of establishing the company Icy mix in El Salvador as an option for ice dessert. This will be different from what is currently on the market, since it is a product in between shaved ice and ice cream, more known as the Taiwanese shaved snow ice; however, it´s considered to be under the shaved ice industry. Currently in El Salvador, this industry is not yet developed, since there are not many formal companies that sell this product and them don´t have much awareness in the market, the main familiar to consumers are the push-cart vendors on the streets, which are not easy to find, because they are constantly moving in the search for clients. This represents an opportunity for the company to enter the market with an organized plan, using as an advantage the weather in the country, which average is between 28 to 22 Celsius degrees in the internal plateau. The business will consist in a food shop located in a middle and upper class mall of the country, where consumers will buy the product to takeaway. After doing the research, we are confident that Icy mix will be a popular choice for consumers who are interested in having a healthy option of ice or frozen dessert, looking to cool off and enjoy a delicious treat.
748

An assessment of needle ice, snowfall and the zero-curtain effect and its relationship with soil frost dynamics on sub-Antartic Marion Island

Zilindile, Mphumzi Brooklyn January 2013 (has links)
This study aims to uncover the synoptic weather circulation pattern which is associated with the occurrence of needle ice, snowfall and the zero-curtain effect. The method of study was done through an intensive ground climate measurement campaign from April 2008 to May 2009 with a temperature logger installed throughout the recording period. Results from data analyses indicate that the complex changes in climate parameters may lead to an equally complex response in terms of spatial soil frost dynamics and its direct and indirect effects on soil sediment displacement and ecosystem dynamics. Field evidence in the study suggests that on Marion Island needle ice developed in temperatures as high as -0.2 ºC in strong winds. This confirms that the wet environment of Marion Island, which is dominated by diurnal soil frost is fundamentally different from seasonal frost and permafrost environments. The scoria material is susceptible to needle ice growth and the compacted soil alters the micro-climatology of the affected area making it more susceptible to the formation of needle ice. Soil moisture for needle ice formation and growth is provided by the misty conditions associated with the advent of the cold front (pre-cyclonic). Furthermore, observations of needle ice on Marion show that needles are mostly clear with no sediment inclusion. This is indicative of needle ice formation that has not been interrupted by a shortage of moisture. The zero-curtain effect on Marion Island can occur either as a response to the thawing of the soil after the seasonal freeze. The synoptic assessment of snowfall on Marion Island indicates that; snowfall is associated with the passage of a cold front linked to a strong meridional system of low pressure just south of the island.
749

Suverénní dluhová krize v Eurozoně / The sovereign debt crisis in the Euro area

Pilař, Tomáš January 2013 (has links)
This dissertation thesis focuses on complex analysis of the problem, which is the sovereign debt crisis in the Euro area. The aim of this paper is to provide a complex overview and analysis of the current sovereign debt crisis, from the theoretical definition of the term, through an analysis of the causes and consequences of this crisis to outline the economic policy response to it. The text is divided into two parts. The first part deals with theoretical problem solving. In the second part is analyzed and described course of sovereign debt crisis. This section also analyzes in detail causes and consequences of the sovereign debt crisis in certain countries. This section is completed by an analysis of economic policy response to the sovereign debt crisis and an expert estimate of the future development of public debt countries analyzed.
750

Analýza rozhodujících příčinných faktorů z hlediska tvorby erozního smyvu z tání sněhové pokrývky / Analysis of the decisive causal factors from the viewpoint of erosion creation from the melting of the snow cover

Moravcová, Aneta Unknown Date (has links)
Currently there is no suitable and commonly used device for volumetric quantification of snowmelt erosion in the Czech Republic (CR). The determination of erosion rate in the catchment is a essential prerequisite for the correct design of conservation measures. The thesis tries to offer the possible ways of monitoring the snowmelt erosion, compares individual methods and defines their optimal use. In the first year of the research, a runoff plot was developed to capture sheet erosion. The thesis compares also the methods using mobile devices - erosion bridge method and UAV photogrammetry - as effective instrument for snowmelt erosion monitoring. So far, no attention has been paid to snowmelt erosion in CR. Therefore, the thesis focuses mainly on the analysis of causal factors specific to this type of erosion - the erosion potential of snow cover and the possible soil erodibility changes due to freeze-thaw cycles. The thesis assesses the rate of snowmelt erosion risk in selected climatically different catchments and its changes in recent years. shows the timeliness of the problem. In the end, the thesis presents possibilities for solving the problem. The thesis claims the problem of snowmelt erosion actual and offers its possible solution.

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