La lithographie de nano-impression par déstabilisation spontanée de polymère est unevariante de la technique de nano-impression thermique, et permet de limiter le contact directentre moule et polymère. Le but de cette thèse est d’étudier cette déstabilisation spontanée etde déterminer si elle peut conduire à la formation de nanostructures en dupliquant de façonpositive un moule nano-structuré. Ce procédé est influencé, en particulier, par la température,le champ électrique externe ou interne au niveau des interfaces moule – air – polymère, ainsique par la distance d séparant les structures du moule et la surface du polymère.Les études réalisées au cours de cette thèse se sont concentrées sur l’influence de cesdifférents paramètres. Nous avons montré que la formation de motifs dépend plus de l’effetde charges que de la température, dans la mesure où le polymère peut néanmoins fluer. Nousavons surtout mis en évidence le scénario de structuration suivant : une duplication positiveapparaît dans un premier temps, et est suivie, dans certains cas, d’un remplissage des cavitésdu moule conduisant à une duplication négative. Un modèle théorique a été utilisé pourcalculer la longueur d’onde de déstabilisation la plus favorable, et une comparaison avec nosrésultats expérimentaux a permis d’expliquer pourquoi et dans quels cas la structurationfinale est positive ou négative. Une investigation a été accomplie sur la déstabilisationspontanée de substrats souples, mais la grande épaisseur des films conduit à unedéstabilisation de grande longueur d’onde, et donc à un remplissage complet du moule. / NanoImprint lithography by spontaneous polymer destabilization is an alternative toThermal NanoImprint, which limits physical contact between polymer and mold surfaces.The purpose of this thesis is to investigate this spontaneous destabilization and to work out ifit can lead to the formation of nanostructures by duplicating positively a structured mold.This process is in particular affected by temperature or electric field present at mold - air -polymer interfaces and by the distance d between the structures of the mold and the polymersurface.The studies of this thesis were focused on the influence of these process parameters. Itwas shown that the structuration depends more of charges’ effect than temperature, since thepolymer can creep. We highlighted the following scenario of structuration: a positiveduplication appears first and is followed, in some cases, by the filling of the mold cavitiesleading to a negative duplication. A theoretical model was used to calculate the mostfavorable destabilization wavelength, and a comparison with experimental results helped toexplain why and under which circumstances the final structuration is positive or negative. Aninvestigation was performed on the spontaneous destabilization of flexible substrate but thebigger thickness of flexible films led to a destabilisation with a wide wavelength and so tothe filling of molds’ cavities.

Micrasterias rotata is a phylogenetically and morphologically well defined species that is widely distributed in Central Europe in a broad temperature gradient. For its complex cell shape Micrasterias rotata is a suitable model organism for cell morphogenesis research. This thesis investigated whether there could be a different pattern in morphological integration resulting from the temperature stress in Micrasterias rotata cells cultivated on a temperature gradient. The optimum and a limits of growth on the temperature gradient were related to the sampling locations of the studied strains isolated from a lowland wetland and an high alpine lake. Differences in the growth rates among the strains suggested a local adaptation to the climatic conditions of the original locations but relatively high values of the assumed optimum growth temperature suggested an intra- species evolutionary adaptation. The temperature-related size reduction rule was not confirmed; however, a similar pattern of variation in shape occurred in both strains. The morphological integration analysis has basically confirmed that the Micrasterias cell is composed of a number of morphological modules related to its differentiation into the lobes and sublobes. Integration between the lobes of the opposite semicell was primarily...

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.

This thesis deals with reconstruction of the heating system of the house after insulation and window replacement. First, the work deals with the description of the building, where are solved the structural elements and building construction and the original heating system is described. Another part deals with the selection of appropriate thermal insulation of external walls and roofs. The work deals with the detailed calculation of the nominal heat performance including domestic water heating. Subsequently, it is focused on solutions of suitable reconstruction of the heating system, which deals with the heat source, hot water circulation, radiators, temperature gradient, heating system security and temperature regulation of water in the domestic water storage heater. In the annexes are inserted construction drawings and the drawings of heating system. Drawings of heating systems are processed for the original condition. For the condition after insulation drawings are already processed with the proposed renovation of the heating system.

With the advances in research of the Hot Dry Rock environment and Enhanced Geothermal Systems, geothermal energy is soon going to compete with other unconventional energy resources in Europe where Germany and France are pushing the research ahead. In the Czech Republic, the geothermal exploration borehole drilled in Litoměřice in 2006 - 2007 provided information that contributed greatly to the understanding of geothermic conditions in the country. In addition to Litoměřice, two other areas have been recently subject to geothermal exploration: Semily and Liberec. These three areas have been studied in detail in this Master's thesis to assess their geothermal potential. Information on the geology of the selected areas was gathered from numerous scientific papers and reports and was compared with information from geological maps and boreholes. On the basis of this information, geological sections of the area of Litoměřice and Semily were compiled. Drill core samples from five boreholes from the geological units in the areas under investigation were collected and measured using the Lippmann & Rauen Thermal Conductivity Scanner. Thermal conductivity of geological units inferred in the basement but not intersected in the boreholes was estimated on the basis of values presented in literature. Finally,...

The ability to rapidly detect and identify hazardous analytes in the field has become increasingly important. One of the most important analytical detection methods in the field is gas chromatography-mass spectrometry (GC-MS). In this work, a hand-portable GC-MS system is described that contains a miniature toroidal ion trap mass analyzer and a low thermal mass GC. The system is self-contained within the dimensions of 47 x 36 x 18 cm and weighs less than 13 kg. Because the instrument has a small footprint, it was used as the detector for an automated near-real-time permeation testing system. In permeation testing, materials that are used to make individual protective equipment such as gloves, masks, boots, and suits are exposed to hazardous analytes to determine how long the equipment can be worn safely. The system described herein could test five samples simultaneously. A multi-position valve rotated among the various sample streams and delivered time aliquots into the MS for quantitation. Current field air sampling techniques suffer from long desorption times, high pressure drops, artifact formation and water retention. These disadvantages can be avoided by concentrating the analytes in short open tubular traps containing thick films. There are several advantages to using polymer coated capillaries as traps, including fast desorption, inertness and low flow restriction. An air sampling trap was constructed utilizing open tubular traps for the concentration of semi-volatile organic compounds. The system consisted of multiple capillary traps bundled together, providing high sample flow rates. The analytes were desorbed from the multi-capillary bundle and refocused in a secondary trap. The simultaneous focusing and separation effect of a trap subjected to a negative temperature gradient was also explored. In this configuration, analytes were focused because the front of the peak was at a lower temperature than the rear of the peak and, hence, moved slower. In addition to the focusing effect, analytes with different volatilities focused at different temperatures within the gradient, allowing for separation.

Vid extrudering av aluminiumprofiler introduceras en temperaturgradient i götmaterialet för att motverka den extra värme som uppstår under processen och tros påverka de mekaniska egenskaperna hos profilen. Detta examensarbete, utfört i samarbete med Hydro Extrusions, undersökte hur götets temperaturgradient påverkar de mekaniska egenskaperna hos extruderade aluminiumprofiler. Arbetet grundade sig i en modifierad DMAIC-metodik där Control-delen exkluderats. Dragprov genomfördes för att undersöka sträckgräns, brottgräns, töjning och elasticitetsmodul hos T4- och T6-åldrade profiler av legeringarna EN AW-6060 och EN AW-6082. Även profilernas utlöpningstemperatur, utlöpningshastighet och kylningshastighet undersöktes. Resultaten visade att temperaturgradienten inte direkt påverkade de mekaniska egenskaperna hos profilerna. Istället bidrog den till att maximera profilens utlöpningshastighet. De största faktorerna som påverkade de mekaniska egenskaperna var vilken åldring och kylningsmetod som användes. / During the extrusion of aluminum profiles, a temperature gradient is introduced into the billet to counteract the extra heat generated during the process and is believed to affect the mechanical properties of the profile. This thesis, carried out in collaboration with Hydro Extrusions, examined how the temperature gradient in the billet affects the mechanical properties of extruded aluminum profiles.  The work was based on a modified DMAIC methodology where the Control phase was excluded. Tensile tests were conducted to investigate the yield strength, ultimate tensile strength, elongation, and modulus of elasticity of T4- and T6-aged profiles of the alloys EN AW-6060 and EN AW-6082. The profile’s exit temperature, exit speed, and cooling rate was also investigated. The results showed that the temperature gradient did not directly affect the mechanical properties of the profiles. Instead, it contributed to maximizing the profile's exit speed. The largest factors influencing the mechanical properties were the aging and cooling methods used.

<p><strong><p>Studie av koldioxidgradienter i havets ytskikt</p><p>Sofia Söderholm</p></strong></p><p>Denna studie bygger på ett nyligen utvecklat instrument som har mätt koldioxidkoncentrationer på tre olika djup i vattnet samt en nivå i luften. Då detta instrument var oprövat i vatten har en utvärdering av mätmetodens lämplighet för vattenmätningar utförts. Syftet med mätningarna var att undersöka ytvattnets vertikala koldioxidgradient för att med hjälp av denna kunna beskriva flödet av koldioxid mellan hav och atmosfär bättre. Detta flöde är en viktig del av den globala kolcykeln och en djupare förståelse för koldioxidflödets beteende kan i framtiden bidra till mer noggranna klimatprognoser. Hur de beräknade flödena från profilinstrumentet påverkas av temperaturgradienterna i vattnets ytskikt har även det studerats. Mätningarna utfördes i vattnet utanför mätstationen på Östergarnsholm, öster om Gotland. En del av studien fokuserar på de horisontella koldioxidgradienterna i ytvattnet som erhållits genom fartygsdata.</p><p>Instrumentet som har använts vid mätningarna bygger på hydrofoba, luftgenomträngliga membran och förefaller fungera mycket väl i vatten. Vid vindhastigheter som inte är högre än 3 - 4 m/s kan tydliga koldioxidgradienter i vattnets ytskikt ses, men detta samband behöver verifieras med en större mängd mätdata. Temperaturgradienten i vattnets ytskikt har ingen större påverkan på vare sig koldioxidgradienten eller flödet av koldioxid och dess effekt kan försummas i detta fall. De horisontella koldioxidgradienterna påverkas huvudsakligen av temperaturen, den biologiska aktiviteten samt transport av vattenmassor. På en större skala kan tydliga effekter av temperaturen på koldioxidhalterna ses och på en mindre skala samt nära kuster och under våren är den biologiska aktiviteten dominerande.</p><p><em><p>Nyckelord: Koldioxidgradient, koldioxidflöde, temperaturgradient, hydrofoba luftgenomträngliga membran, transferhastighet, vindhastighet, biologisk aktivitet.</p></em></p> / <p><strong><p>A study regarding the carbon dioxide gradients in the surface water.</p><p>Sofia Söderholm</p></strong></p><p>This study is based on a recently developed instrument that measures the concentration of carbon dioxide at three different depths in the water and one level in the air. Since this instrument has not previously been used for measurements in water, an evaluation regarding the usefulness of the instruments for measurements in water was made. The purpose of the measurements was to study the vertical gradient of carbon dioxide in the surface water and to describe the vertical flux of carbon dioxide between the ocean and the atmosphere in an improved way. This flux is an important part of the global carbon cycle and a deeper understanding of the behavior of the air-sea exchange of carbon dioxide could contribute to more accurate forecasts of the future climate. The impact on the calculated carbon dioxide flux by the temperature gradients in the surface waters was also analyzed. The measurements were performed in the waters outside of the island of Östergarnsholm, east of Gotland. Part of the study focuses on the horizontal carbon dioxide in the surface water, which was obtained by ship data.</p><p>The instrument used when performing the measurements is based on hydrophobic, air-permeable membranes and appears to function very well in water. During wind speeds below 3 - 4 m/s distinct carbon dioxide gradients can be seen for the investigated data, but more data is needed to quantify this gradient for different situations. The temperature gradient in the surface water doesn't have a significant effect on the carbon dioxide gradient or the flow of carbon dioxide, and the effect of the temperature gradient can in this particular case be neglected. The horizontal gradients of carbon dioxide are mainly affected by temperature, biological activity and transportation of water mass. On a larger scale the effects of temperature on the concentrations of carbon dioxide are visible and on a smaller scale along with the coastal areas and during springtime, the biological activity is the dominating influence.</p><p><em><p>Keywords: Carbon dioxide gradient, carbon dioxide flux, temperature gradient, hydrophobic airpermeable membranes , transfer velocity, wind speeds, biological activity.</p></em></p>

This study investigated the transport coefficients involved in mass and heat transfer during the drying of a porous solid partially saturated with multicomponent mixtures.  It included the coefficients governing liquid transport through the solid, the matrix of multicomponent diffusion coefficients in the liquid phase, and the effective thermal conductivity.  As it is not possible to determine these coefficients by theoretical considerations alone and considerable experimental work is required to determine them in a broad range of process conditions, the principle of this study has been the use of mathematical models complemented with some empirical parameters.  These empirical parameters were determined by comparison between measurements in specially designed experiments and the results of mathematical models that describe the process.  In addition, the application of the multicomponent diffusion coefficients is described in two cases where liquid diffusion is important: convective evaporation of a multicomponent stationary liquid film and a falling film. To study liquid transport through the solid, isothermal drying experiments were performed to determine the transient composition profiles and total liquid content of sand samples wetted with ternary liquid mixtures with different initial compositions and temperatures.  A mathematical model including mass transfer by capillary movement of the liquid and interactive diffusion in both the gas and liquid phases was developed.  To simulate the capillary movement of liquid mixtures, parameters experimentally determined for single liquids were weighed according to liquid composition. A fairly good agreement between theoretical and experimental liquid composition profiles was obtained considering that axial dispersion was included in the model. To study the matrix of multicomponent diffusion coefficients in the liquid phase, the redistribution of liquid composition in a partially filled tube exposed to a longitudinal temperature gradient was analysed.  Experimental work was carried out using two main ternary mixtures with different initial compositions and temperature gradients.  Experimental data were compared with the results of a theoretical model that describes the steady-state liquid composition distribution in a partially filled non-isothermal tube to find the empirical exponent that modifies the matrix of thermodynamic factors.  Correlations for the exponents as a function of temperature were determined for each particular multicomponent mixture. The effective thermal conductivity of a porous solid containing multicomponent liquid mixtures was studied by measuring the liquid composition, liquid content and temperature distributions in a cylindrical sample dried by convection from the open upper side and heated by contact with a hot source at the bottom side.  Simulations performed at a quasi steady state were compared with experiments to estimate the adjusting geometric parameter of Krischer’s model for effective thermal conductivity, which includes the contribution of the evaporation-diffusion-condensation mechanism. The results revealed that a resistance corresponding to a parallel arrangement between the phases seems to dominate in this case. In the study of the convective drying of a multicomponent stationary liquid film, the equations describing interactive mass transfer were decoupled by a similarity transformation and solved simultaneously with a conduction equation by the method of variable separation.  Variations of physical properties along the process trajectory were taken into account by a stepwise application of the solution in time intervals with averaged coefficients from previous time steps.  Despite simplifications, the analytical solution gives a good insight into the selectivity of the drying process and is computationally fast.  On the other hand, numerical simulations of the convective evaporation of the multicomponent falling liquid film into an inert gas with a co-current flow arrangement of the phases almost always revealed a transition from liquid-phase-controlled conditions to a process in which neither the gas nor the liquid completely controls the evaporation. The results obtained in this work would be useful in implementing models to improve the design, process exploration and optimisation of dryers by incorporating the solid-side effects to describe the drying of liquid mixtures along the whole process. / QC 20110124

Studie av koldioxidgradienter i havets ytskikt Sofia Söderholm Denna studie bygger på ett nyligen utvecklat instrument som har mätt koldioxidkoncentrationer på tre olika djup i vattnet samt en nivå i luften. Då detta instrument var oprövat i vatten har en utvärdering av mätmetodens lämplighet för vattenmätningar utförts. Syftet med mätningarna var att undersöka ytvattnets vertikala koldioxidgradient för att med hjälp av denna kunna beskriva flödet av koldioxid mellan hav och atmosfär bättre. Detta flöde är en viktig del av den globala kolcykeln och en djupare förståelse för koldioxidflödets beteende kan i framtiden bidra till mer noggranna klimatprognoser. Hur de beräknade flödena från profilinstrumentet påverkas av temperaturgradienterna i vattnets ytskikt har även det studerats. Mätningarna utfördes i vattnet utanför mätstationen på Östergarnsholm, öster om Gotland. En del av studien fokuserar på de horisontella koldioxidgradienterna i ytvattnet som erhållits genom fartygsdata. Instrumentet som har använts vid mätningarna bygger på hydrofoba, luftgenomträngliga membran och förefaller fungera mycket väl i vatten. Vid vindhastigheter som inte är högre än 3 - 4 m/s kan tydliga koldioxidgradienter i vattnets ytskikt ses, men detta samband behöver verifieras med en större mängd mätdata. Temperaturgradienten i vattnets ytskikt har ingen större påverkan på vare sig koldioxidgradienten eller flödet av koldioxid och dess effekt kan försummas i detta fall. De horisontella koldioxidgradienterna påverkas huvudsakligen av temperaturen, den biologiska aktiviteten samt transport av vattenmassor. På en större skala kan tydliga effekter av temperaturen på koldioxidhalterna ses och på en mindre skala samt nära kuster och under våren är den biologiska aktiviteten dominerande. Nyckelord: Koldioxidgradient, koldioxidflöde, temperaturgradient, hydrofoba luftgenomträngliga membran, transferhastighet, vindhastighet, biologisk aktivitet. / A study regarding the carbon dioxide gradients in the surface water. Sofia Söderholm This study is based on a recently developed instrument that measures the concentration of carbon dioxide at three different depths in the water and one level in the air. Since this instrument has not previously been used for measurements in water, an evaluation regarding the usefulness of the instruments for measurements in water was made. The purpose of the measurements was to study the vertical gradient of carbon dioxide in the surface water and to describe the vertical flux of carbon dioxide between the ocean and the atmosphere in an improved way. This flux is an important part of the global carbon cycle and a deeper understanding of the behavior of the air-sea exchange of carbon dioxide could contribute to more accurate forecasts of the future climate. The impact on the calculated carbon dioxide flux by the temperature gradients in the surface waters was also analyzed. The measurements were performed in the waters outside of the island of Östergarnsholm, east of Gotland. Part of the study focuses on the horizontal carbon dioxide in the surface water, which was obtained by ship data. The instrument used when performing the measurements is based on hydrophobic, air-permeable membranes and appears to function very well in water. During wind speeds below 3 - 4 m/s distinct carbon dioxide gradients can be seen for the investigated data, but more data is needed to quantify this gradient for different situations. The temperature gradient in the surface water doesn't have a significant effect on the carbon dioxide gradient or the flow of carbon dioxide, and the effect of the temperature gradient can in this particular case be neglected. The horizontal gradients of carbon dioxide are mainly affected by temperature, biological activity and transportation of water mass. On a larger scale the effects of temperature on the concentrations of carbon dioxide are visible and on a smaller scale along with the coastal areas and during springtime, the biological activity is the dominating influence. Keywords: Carbon dioxide gradient, carbon dioxide flux, temperature gradient, hydrophobic airpermeable membranes , transfer velocity, wind speeds, biological activity.