For centuries in the future, the climate on Earth will be affected by the global warming.Effects as melting ices, increasing sea levels and extreme weather, are all consequencesof the high amount of carbon dioxide (CO2), that we humans have caused. In Sweden,can climate effects like higher temperatures, longer vegetation periods and greaterseasonal variations in water fluxes, be expected. Due to climate changes and anincreasing population, the drinking water production in Uppsala will be affected. Interms of securing the drinking water production in the future, Uppsala Vatten och Avfall AB are investigating the possibility to use the Ekoln basin in lake Mälaren, as acomplementary raw water catchment area. In order to keep a secure drinking water production, in regard to quantity and quality, itis of interest to investigate how fluxes and water quality will be affected in the future.The annual pattern of water mixing, with summer- and winter stratification, and overturnduring spring and autumn, is something that significantly affects the water quality in theSwedish lakes. With the aim to study how the annual pattern of water mixing in theEkoln basin, might change due to future climate changes, hydrodynamic modelling wasperformed on a model area consisting of the Ekoln basin with adjacently bays. A hydrodynamic (3D) transport model of type MIKE 3 Flow Model FM, created byTyréns AB for simulating transport of pollutions, was calibrated and adapted to simulatetemperature profiles in the model area. To be able to study the annual pattern of watermixing, the model was also adapted to simulate a period of a year. Three scenarios weresimulated, one reference year and two future scenarios, where the future scenarios werebased on the climate scenarios RCP4.5 and RCP8.5 in year 2050. The calibration of the model was successful, and the calculation time was reduced byadapting the mesh. Results from the three scenarios, showed that the period with summerstratification might become nine days longer by RCP4.5 in year 2050, compared to thereference scenario. Simulation of RCP8.5 during the same time period, did not showany changes. By RCP8.5 it is possible that water temperatures in the epilimnion, areincreasing and that there will be no winter stratification. The temperature in the surfacewater are affected by the air temperature, in future studies it is in interest to investigatehow stratification and cirkulation will be affected by changes in wind speed and winddirection, how different types of wind data effect the results, it is also in interest to studychanges during a time period longer than one year. / Den globala uppvärmningen kommer att påverka Jordens klimat i många sekel framöver.Effekter som smältande isar, stigande havsnivåer och extremare väder, är allakonsekvenser av de enorma utsläpp koldioxid (CO2), som vi människor orsakat. ISverige kan vi i framtiden vänta oss varmare temperaturer, längre vegetationsperioderoch flöden med stora säsongsvariationer. I Uppsala kommer de framtidaklimatförändringarna i samverkan med en växande befolkning att påverka stadensdricksvattenproduktion. Uppsala Vatten och avfall AB undersöker idag möjligheten tillatt använda Mälarbassängen Ekoln som kompletterande råvattentäkt. För att säkerställa en säker dricksvattenproduktion, både utifrån den kvantitet ochkvalitet som krävs, är det av intresse att veta hur flöden och vattenkvalitet i Ekoln kankomma att utvecklas i framtiden. Något som i stor grad påverkar vattenkvaliteten i våraSvenska sjöar, är den årstidsbundna cirkulationen, med vinter- och sommarstagnation,samt vår- och höstcirkulation. För att undersöka hur den årstidsbundna cirkulationen iEkoln kan komma att förändras med framtida klimat, utfördes hydrodynamiskmodellering för sjön med intilliggande vikar. En bestående tredimensionell spridningsmodell av typ MIKE 3 Flow Model FM, skapadför att simulera spridning av avloppsvatten i Ekoln, erhölls från Tyréns AB. Modellenkalibrerades och anpassades för att simulera temperaturprofiler i sjön. För att täcka inbeteendet för den årstidsbundna cirkulationen anpassades modellen till att simulera etthelt år. Modellen kördes för ett referensår, samt för de två strålningsdrivningsscenariernaRCP4.5 och RCP8.5 vid år 2050. Kalibrering av modellen var lyckad och beräkningstiden förkortades genom anpassningav beräkningsnätet. Resultat från simuleringar visade på att sommarstagnation kanförekomma nio dagar längre vid RCP4.5 för år 2050, än under referensåret. Ingenförändring förväntas vid RCP8.5 under samma tidsperiod. Vid RCP8.5 förväntas dockvattentemperaturer i epilimnion att stiga och vinterstagnation förekommer ej.Temperaturer i vattenmassans övre skikt påverkas i hög grad av lufttemperatur och vidfortsatta studier är det även av intresse att undersöka hur skiktning och cirkulationpåverkas av förändrade vindförhållanden, hur olika drivdata för vindförhållandenpåverkar resultatet samt att undersöka en tidsperiod som är längre än ett år.

Esta tese tem por objetivo propor uma metodologia para recuperação de perfis verticais de temperatura na atmosfera com nuvens a partir de medidas de radiância feitas por satélite, usando redes neurais artificiais. Perfis verticais de temperatura são importantes condições iniciais para modelos de previsão de tempo, e são usualmente obtidos a partir de medidas de radiâncias feitas por satélites na faixa do infravermelho. No entanto, quando estas medidas são feitas na presença de nuvens, não é possível, com as técnicas atuais, efetuar a recuperação deste perfil. É uma perda significativa de informação, pois, em média, 20% dos pixels das imagens acusam presença de nuvens. Nesta tese, este problema é resolvido como um problema inverso em dois passos: o primeiro passo consiste na determinação da radiância que atinge a base da nuvem a partir da radiância medida pelos satélites; o segundo passo consiste na determinação do perfil vertical de temperaturas a partir da informação de radiância fornecida pelo primeiro passo. São apresentadas reconstruções do perfil de temperatura para quatro casos testes. Os resultados obtidos mostram que a metodologia adotada produz resultados satisfatórios e tem grande potencial de uso, permitindo incorporar informações sobre uma região mais ampla do globo e, consequentemente, melhorar os modelos de previsão do tempo. / This thesis presents a methodology for retrieving vertical temperature profiles in the atmosphere with clouds from radiance measurements made by satellite, using artificial neural networks. Vertical temperature profiles are important initial conditions for numerical weather prediction models, and are usually obtained from measurements of radiance using infrared channels. Though, when these measurements are performed in the atmosphere with clouds, it is not possible to retrieve the temperature profile with current techniques. It is a significant loss of information, since on average 20% of the pixels of the images have clouds. In this thesis, this problem is solved as a two-step inverse problem: the first step is an inverse problem of boundary condition estimation, where the radiance reaching the cloud basis is determined from radiance measured by satellite; the second step consists in determining the vertical temperature profile from the boundary condition estimated in the first step. Reconstructions of temperature profile are presented for four test cases. The results show that the proposed methodology produces satisfactory results and has great potential for use, allowing to incorporate information from a wider area of the planet and thus to improve numerical weather prediction models.

Esta tese tem por objetivo propor uma metodologia para recuperação de perfis verticais de temperatura na atmosfera com nuvens a partir de medidas de radiância feitas por satélite, usando redes neurais artificiais. Perfis verticais de temperatura são importantes condições iniciais para modelos de previsão de tempo, e são usualmente obtidos a partir de medidas de radiâncias feitas por satélites na faixa do infravermelho. No entanto, quando estas medidas são feitas na presença de nuvens, não é possível, com as técnicas atuais, efetuar a recuperação deste perfil. É uma perda significativa de informação, pois, em média, 20% dos pixels das imagens acusam presença de nuvens. Nesta tese, este problema é resolvido como um problema inverso em dois passos: o primeiro passo consiste na determinação da radiância que atinge a base da nuvem a partir da radiância medida pelos satélites; o segundo passo consiste na determinação do perfil vertical de temperaturas a partir da informação de radiância fornecida pelo primeiro passo. São apresentadas reconstruções do perfil de temperatura para quatro casos testes. Os resultados obtidos mostram que a metodologia adotada produz resultados satisfatórios e tem grande potencial de uso, permitindo incorporar informações sobre uma região mais ampla do globo e, consequentemente, melhorar os modelos de previsão do tempo. / This thesis presents a methodology for retrieving vertical temperature profiles in the atmosphere with clouds from radiance measurements made by satellite, using artificial neural networks. Vertical temperature profiles are important initial conditions for numerical weather prediction models, and are usually obtained from measurements of radiance using infrared channels. Though, when these measurements are performed in the atmosphere with clouds, it is not possible to retrieve the temperature profile with current techniques. It is a significant loss of information, since on average 20% of the pixels of the images have clouds. In this thesis, this problem is solved as a two-step inverse problem: the first step is an inverse problem of boundary condition estimation, where the radiance reaching the cloud basis is determined from radiance measured by satellite; the second step consists in determining the vertical temperature profile from the boundary condition estimated in the first step. Reconstructions of temperature profile are presented for four test cases. The results show that the proposed methodology produces satisfactory results and has great potential for use, allowing to incorporate information from a wider area of the planet and thus to improve numerical weather prediction models.

Diploma thesis was dealing with design of the device for measuring the mean temperature in a channel of any cross-section. First, the theory of heat, heat transfer and fluid flow was summarized. Theory was focused specially on the uneven temperature distribution in the flowing medium. Furthermore, a general overview of commercially used temperature sensors and developed sensors with applicability to the investigated problematics was elaborated. Then, a device for sensing mean temperature in a flow channel for several different diameters has been fully designed and developed. The device included the temperature sensor itself, the necessary measurement electronics and its programming, and a simple measurement data application.

This thesis mainly deals with the prediction of temperature on the components and the PCB during reflow soldering. The theoretical part describes the particular solder reflow process, types of heat transfer and temperature profiles. The practical part is divided into forecasting temperatures if the conveyor is stopped and the temperature predictions when the conveyor is in motion. In both parts of the measured temperature is compared with the predicted temperatures, which show the success rate of prediction. The last part of this work is part of the simulation, which helps in proper understanding of the issues discussed.

This work deals with the laser diode soldering. The theoretical part summarizes general and acquired findings about soldering technology and materials that occur in this process. It also describes factors that affect the reliability of solder joints. It is closely focused to the shaping of the solder joint and structure of intermetallic layer. The practical part of this work is focused on the design of equipment for laser diode soldering and subsequent shaping of the samples. The quality of soldered joint is compared against the quality of joint created using re-flow technology - remelting in in-line smelter. The structure and thickness of the intermetallic layer, the number and shape of the voids in the solder joints are compared.

The project deals with the overall design and construction of equipment called the desiccators for brazing in a protective atmosphere. The device was designed and manufactured cooling and heating element. For the soldering various temperature profiles have been defined and adjusted, as for SnPb as well for lead-free solders. There was a realization of samples were measured and analyzed. Finally were realized micro sections for lead free solder.

We are facing an important challenge, to reduce the greenhouse gas emissions to make sure that we limit global warming to 2 °C, preferably 1.5 °C. Drastic changes and developing new methods may be our only chance to keep global warming under 1.5 °C. The steel production in Sweden today accounts for 10% of the CO2 emission. The joint venture HYBRIT (Hydrogen Breakthrough Ironmaking Technology), between SSAB, LKAB and Vattenfall, aims to reduce the CO2 emission by developing a method that reduces iron ore pellets with hydrogen gas, leaving only water as off-gas. From simple thermodynamic calculations, it is evident that the reduction of iron ore using hydrogen gas is an endothermic reaction, requiring heat. Based on the calculated energy requirement, the temperature at the center of the pellet should not be the same as the temperature at the surface of the pellet but instead, decrease as the reduction reaction takes place. This report presents the temperature profile at the surface and in the center of a hematite pellet during hydrogen reduction at temperatures of 600 °C, 700 °C, 800 °C and 900 °C. Ideally, the results can be implemented in a model to better simulate the reduction reaction taking place inside a hematite pellet. The experiment consists of three sub-experiments, the first measures the temperature profile of the unreduced iron ore pellet in an argon gas atmosphere, secondly, the temperature profile and mass loss are measured during reduction, lastly, the temperature profile is measured for the reduced pellet in a hydrogen atmosphere. The mass loss measured during hydrogen reduction is used to calculate the degree of reduction. The results show that the reaction rate increases with increasing temperature and concentration of H2. Additionally, a higher reduction temperature gives the largest temperature decrease inside the pellet during reduction. At 900 °C, the temperature decrease is equal to 39 °C and at 600 °C, it is equal to 3 °C. The results prove that after a certain initial stage, gas diffusion and heat conduction through the product layers play important roles in controlling the reaction rate. There is even a period where a plateau of the reduction is observed, the reaction is mostly controlled by heat transfer. / Idag står vi inför en viktig utmaning, att minska utsläppen av växthusgaser och se till så att vi inte överskrider 2 °C uppvärmning, helst inte 1.5 °C. För att klara detta krävs drastiska förändringar och utvecklingar av nya metoder kan vara vår enda chans att uppnå 1.5-gradersmålet. Ståltillverkningen i Sverige idag står för 10% av CO2 utsläppen och för att bidra till att minska utsläppen av CO2 har företaget HYBRIT, vilket står för Hydrogen Brakethrough Ironmaking Technology, skapats. HYBRIT är en joint venture mellan SSAB, LKAB och Vattenfall som tillsammans vill skapa stål på ett mer miljövänligt sätt. Processen går ut på att reducera järnmalmspellets med hjälp av vätgas för att producera järnsvamp och ge ifrån sig vatten som avgas. Från enkla termodynamiska beräkningar är det lätt att inse att reduktionen med hjälp av vätgas är en endoterm process, som kräver energi. Det är genom denna kunskap som en kan föreställa sig att reduktionen av järnmalmspellets med hjälp av vätgas kommer bidra till en temperaturminskning. I denna rapport har temperaturprofilen inne i och på ytan av en hematitpellet mätts under tiden som den blivit reducerad med vätgas. Idealt kan resultaten implementeras i en modell för att bättre simulera reduktionsreaktionen som äger rum i en hematitpellets. Fyra olika reduktionstemperaturer har undersökts: 600 °C, 700 °C, 800 °C och 900 °C. Experimenten består av tre del-experiment, först mäts temperaturprofilen av den oreducerad hematitpelletsen i en argonatmosfär, sedan mäts viktminskningen och temperaturprofilen av pelleten medan den reduceras i en vätgasatmosfär, slutligen mäts temperaturprofilen av den reducerade pelleten i en argonatmosfär. Viktminskningen under reduktionen används för att beräkna reduktionsgraden under reduktionsförloppet. Resultaten visade att reduktionshastigheten ökade med ökande temperatur och koncentration av H2. Ökad temperatur gav även den största temperaturminskningen inne i pelleten då den reducerats med vätgas. Vid 900 °C uppmätes en temperaturminskning på 39 °C, varav reduktion vid 600 °C gav en temperaturminskning på 3 °C. Resultaten visar att efter en viss tids reduktion, spelar gasdiffusionen och värmeledningen genom produktlagret en viktig roll och är det som begränsar reduktions-hastigheten. Fortsatt, då hematitpelleten reducerades uppstod en platå där temperaturen var konstant och reaktionen till största delen var begränsad av värmeledningen genom produktlagret.

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A l’aide d’un interféromètre différentiel à quadrature de phase nous mesurons les fluctuations thermiques de la déflexion d’un micro-levier. Il est alors possible de déduire différentes propriétés mécaniques du levier telles que raideur, fréquences de résonance, facteurs de qualité etc. Dans un tel système, la précision maximale sur les mesures est limitée par le bruit de grenaille des photodiodes (shot-noise). Afin d’augmenter le rapport signal sur bruit, nous augmentons l’intensité lumineuse du laser de mesure, diminuant ainsi le bruit de fond des spectres de fluctuations thermique. En revanche, l’augmentation de l’intensité du laser a pour effet de décaler vers les basses fréquences les résonances du levier. Une première partie de ce travail de thèse a pour objectif la compréhension de ce phénomène. Ainsi, nous associons le décalage en fréquence à un échauffement du levier par le laser de l’interféromètre et au flux de chaleur associé le long du levier. Nous développons alors un modèle permettant de relier cet effet à la température de l’extrémité du levier en se basant sur un profil de température linéaire. Une seconde partie de ce travail vise à mesurer la température effective d’un levier à l’aide d’une extension du théorème fluctuation-dissipation. Nous montrons que les fluctuations de ce système hors équilibre sont plus faibles que celles attendues compte tenu du profil de température. Nous cherchons alors à identifier l’origine de ce déficit de fluctuations. Dans une dernière partie nous estimons les profils de température sur des leviers en faisant varier leurs paramètres géométriques ou leur coefficient d’absorption, ainsi que la position du laser chauffant le levier. / Thanks to a home made quadrature phase differential interferometer, we measure the thermal fluctuations ofa cantilever. It is then possible to infer various mechanical properties such as eigenfrequencies, stiffness,quality factor, etc. In such system, the maximal precision on the measure is limited by the shotnoise of thephotodiodes. To increase the signal-noise ratio we raise the light intensity of the laser, lowering thebackground noise. Doing so, the cantilever eigen frequencies shifts to lower values. A fisrt part of this thesiswork has for objective the understanding of this phenomenon. Thus, we associate this frequency shift with aheating of the cantilever by the laser. We develop a model linking this effect to the temperature at the freeend of the cantilever assuming a linear temperature profile.A second part of this thesis leads us to estimate the effective temperature of a cantilever using thefluctuation-dissipation theorem. We show that the fluctuations of our out of equilibrium system are lower thanthe fluctuations expected at equilibrium.In the last part, we estimate the temperature profiles on cantilevers by varying their geometry, absorptioncoefficient and laser position.