No description available.

No description available.

No description available.

Absolicon Solar Collector AB in Härnösand, Sweden, develops concentrating solar collectors with a parabolic trough. In the solar collector trough, there is thermal loss due to convection. A convection suppressor was made and used as a method to reduce thermal loss due to convection in the trough. The objective of the project was to evaluate the convection suppressor for solar collectors with a parabolic trough and its impact on the performance (thermal loss characteristics) in two different orientations of the trough, horizontal and inclined. The performance of the solar collector was first measured without the convection suppressor; these results were compared to two previous quasi-dynamical tests of the solar collector performance made by two different institutes, Research Institute of Sweden and SPF Institut für Solartechnik (Switzerland). The comparison was made to validate the test results from the tests without the convection suppressor, which matched. Secondly, when the convection suppressor was made and tested in the two different orientations, the results of the performance with and without the convection suppressor was evaluated as well as the convection suppressor itself. The results showed a significant improvement of the solar collector performance in the aspect of reduced thermal loss when the convection suppressor was used, hence higher efficiency. / Absolicon Solar Collector AB I Härnösand, Sverige, utvecklar koncentrerande solfångare med ett paraboliskt tråg. I solfångarens tråg uppstår termiska förluster som en följd av konvektion. En konvektionsreducerare tillverkades och användes som metod för att minska de termiska förlusterna i tråget. Målet med projektet var att testa och utvärdera konvektionsreduceraren för koncentrerande solfångare med ett paraboliskt tråg samt dess inverkan på verkningsgraden i två olika positioner för tråget, horisontell och lutande. För att kunna mäta konvektionsreducerarens inverkan på solfångaren mättes först solfångarens prestanda utan konvektionsreduceraren i de två olika positionerna, detta resultat användes som referens efter validering. Valideringen gjordes genom att resultatet jämfördes sedan med två andra prestandamätningar (quasi-dynamical test) av solfångaren gjorda av två olika institut, Research Institute of Sweden och SPF Institut für Solartechnik (Schweiz). Därefter, när konvektionsreduceraren var tillverkat och testad i de olika positionerna på samma sätt som mätningarna utan konvektionsreducerare, jämfördes resultaten med och utan konvektionsreducerareet samt att en utvärdering gjordes av dess inverkan. Resultatet visade en signifikant förbättring av solfångarens prestanda i form av minskade termiska förluster när konvektionsreduceraren användes och därav ökad verkningsgrad.

Chlamydomonas reinhardtii possesses a single-cell-based CO2-concentrating mechanism (CCM). The CCM is an important element of algal photosynthesis, metabolism, growth and biomass production, which works by increasing the concentration of inorganic carbon (Ci) in the pyrenoid, a dense RuBisCO-packed structure within the chloroplast. This suppresses RuBisCO oxygenase activity and associated photorespiration. The enhanced efficiency of CO2 assimilation in the pyrenoid via CCM had been modelled theoretically as a requirement for successful CCM in higher plant systems. The ultimate aim of my research is to understand the biogenesis of the pyrenoid using a set of CCM mutants with pyrenoidal defects. Immunofluorescence methods and spot growth tests under different CO2 concentrations were performed on mutants with CCM defects generated by an insertional mutagenesis screen. Morphological and physiological characterisation of these mutants revealed differences in the pyrenoid morphology, the ability for RuBisCO to aggregate into the pyrenoid and the formation of thylakoidal tubule network associated with the pyrenoid. The thylakoid tubule network may be linked to the transport of inorganic carbon into the pyrenoid as part of the CCM. Further characterisation of one of the mutants gave rise to the hypothesis that the gene of interest, Cre11.g467712 (SAGA), is a multi-functional anchor protein related to the structural formation of the pyrenoid and may be another essential component of the pyrenoid.

La responsabilité de notre activité dans les récentes et parfois brutales modifications climatiques est avérée. Maîtrise de la demande en énergie et énergies renouvelables apparaissent comme les deux solutions pour remédier à cette catastrophe. Dans ce travail, nous nous intéressons à la cogénération appliquée aux bâtiments résidentiels. Deux zones géographiques sont concernées, l'Afrique de l'Ouest et la France. Il n'existe pas de système de cogénération solaire de très faible puissance (< 10 kWe). La solution envisagée dans ce travail consiste à produire de la chaleur à environ 150 °C et un rendement supérieur à 50 %, de l'utiliser ensuite dans un ORC pour produire électricité et chaleur à basse température. Le système complet doit être résistant et à bas coût. Or pour atteindre ces performances, la concentration solaire est obligatoire. Une partie de ce travail consiste donc au développement d'un panneau à concentration solaire qui répond à ces deux contraintes thermiques, mais aussi au fait d'être robuste, fiable et facilement intégrable à l'enveloppe d'un bâtiment. Dans ce cadre, la technologie cylindro-parabolique a été retenue, adaptée et miniaturisée. En ce qui concerne la partie thermodynamique, le verrou technologique se trouve principalement dans le groupe turboalternateur. L'objet de la seconde partie de cette thèse consiste ainsi à la conception d'un organe de détente également robuste, nécessitant qu'une maintenance simplifiée et réalisable par les équipes de SIREA. La turbine Tesla, brevetée en 1913 par Nikola Tesla, devrait satisfaire à ce cahier des charges. Sa particularité est qu'à l'opposée des autres turbines, son rotor ne possède pas d'aubage, mais seulement des disques parallèles. Son fonctionnement est basé sur l'adhésion du fluide aux surfaces des disques. / The responsibility of our activity in the recent and sometimes brutal climate changes is recognized. Energy demand management and renewable energies appear as two solutions to overcome this disaster. In this work, we focus on combined heat and power applied to residential buildings. Two geographical areas are concerned, West Africa and France. For the moment, no system of very low power (< 10 kWe) solar cogeneration exists. In this work, considered solution consists to produce heat at 150 °C and with an efficiency greater than 50 %, then to use it in an ORC for producing electricity and low temperature heat. The whole system has to be resistant and low-cost. But to reach those performances with solar radiation, concentration is necessary. The first part of this thesis is to elaborate a solar concentrating panel which answer to these two thermal constraints. The new solar panel must be robust, reliable and easily integrable on the building envelope. In this context, parabolic trough is adopted, adapted and miniaturised. Regarding the thermodynamic part, technological lock is found mainly in the turbogenerator. The purpose of the second part of this thesis consists of the design of a an expansion equipement, requiring simplified maintenance and achievable by the team of Sirea. The Tesla turbine, patented in 1913 by Nikola Tesla, should satisfy this specification. Its characteristic is that the opposite other conventional turbines, the rotor is not bladed or vaned, only parallel disks. Fluid exerts shear stress on the disk surfaces resulting in a torque at the shaft.

O MCH é um neuropeptídeo sintetizado preferencialmente no hipotálamo que exibe projeções para todo o neuroeixo, podendo modular vários processos fisiológicos, como a ingestão aguda de alimento. Um alvo de suas projeções é o núcleo accumbens (Acb), componente do estriado ventral envolvido na recompensa de estímulos hedônicos. Nossa contribuição visa mapear as células imunorreativas (ir) ao MCH responsáveis pelas aferências do Acb, onde também investigamos aposições entre os sistemas MCH, GABA e ChAT. Utilizaram-se os métodos de simples e duplas imunoperoxidases e combinação de imunofluorescência e captação de traçadores retrógrados. A maior densidade de fibras ir-MCH ocupa a parte shell do Acb (AcbSh); as aferências ir-MCH partem, por exemplo, da área hipotalâmica lateral e área perifornicial. Controles anterógrados foram obtidos a partir da LHA. Observaram-se aposições entre terminais ir-MCH e células ir-GABA e ir-ChAT, no AcbSh. Assim, sugere-se que os territórios hipotalâmicos que contém MCH inervem o AcbSh e contatem outros sistemas neuroquímicos no Acb. / MCH is a neuropeptide synthesized preferentially in the hypothalamus that shows projections throughout neuraxis, and may modulate various physiological processes such as food intake. One target of its projections is the nucleus accumbens (Acb), a component of the striatum involved in reward of hedonic stimuli. Our contribution aims to map immunoreactive (ir) cells responsible for the MCH inputs of the Acb, and to investigate appositions between MCH fibers, GABA and ChAT cells. We used the single and double immunoperoxidase methods and immunofluorescence combined with retrograde tracer. The highest density of fiber MCH-ir occupies the shell part of the Acb (AcbSh); MCH-ir inputs are mainly from lateral hypothalamic and perifornical areas. Anterograde controls were obtained from the LHA. We have founded appositions between MCH-ir terminals and GABA- and ChAT-ir cells at AcbSh. Thus, is suggested that hypothalamic areas containing MCH innervate the AcbSh and contact other neurochemical systems systems in the Acb.

Segundo o Atlas Brasileiro de Energia Solar, apesar das diferentes características climáticas observadas no Brasil, pode-se constatar que a média anual de irradiação solar global apresenta boa uniformidade e elevados índices por todo o país. Os valores desta grandeza em quase toda a extensão do território brasileiro (4200-6700 Wh/m2/dia) são superiores aos da maioria dos países da União Europeia, como Alemanha (900-1250 Wh/m2/dia), França (900-1650 Wh/m2/dia) e Espanha (1200-1850 Wh/m2/dia), onde projetos para aproveitamento de energia solar, alguns contando com fortes incentivos governamentais, são amplamente disseminados. Grande parte dos avanços científicos obtidos nos estudos sobre aproveitamento da energia solar se deve à utilização de simuladores solares compactos nos experimentos de longa duração. Ao substituir o Sol por fontes artificiais, como lâmpadas capazes de emitir radiação próxima à solar, os simuladores eliminam a dependência de fatores naturais como condições climáticas, horário do dia, intermitência e movimento de direção da radiação solar. O projeto proposto para esta dissertação de Mestrado teve como objetivo o domínio do processo de concepção e fabricação de um simulador solar concentrador formado por lâmpadas e um refletor ótico. Uma vez dominada a técnica, um modelo piloto de simulador solar foi construído e alguns testes executados para avaliar a qualidade do projeto, a resistência dos componentes e o fator de concentração do aparato. / According to the Brazilian Atlas of Solar Energy, despite the different climatic characteristics observed in Brazil, the annual average of global solar irradiation has good uniformity and high levels throughout the country. The values of global solar irradiation in almost the entire length of Brazil (4200-6700 Wh/m2/day) are higher than those observed in most European Union countries, like Germany (900-1250 Wh/m2/day), France (900-1650 Wh/m2/day) and Spain (1200-1850 Wh/m2/day), where projects for solar energy applications, some of them relying on strong government incentives, are widely disseminated. Several scientific and technological advances made in the study of solar energy applications are due to the use of compact solar simulators in long-term experiments. Replacing the Sun by artificial sources, such as arc lamps with radiation emission similar to the Sun spectrum, indoor simulators avoid the dependence on natural conditions such as the weather, the daytime, the sunlight intermittence and the directional change of the solar radiation. The project proposed for this dissertation aimed to master the design and manufacturing processes of a high-flux solar simulator consisting of arc lamps and an optical reflector. Once technique was understood, a solar simulation pilot model was built and some tests were performed to assess the project quality, the resistance of components and the apparatus concentration factor.

Abstract At least 30 gold deposits verified by means of one or more notable diamond drill hole results have been discovered in Central Lapland in the last 20 years, and these can be divided spatially into groups, between which the metal composition varies. The deposits contain varying amounts of sulphides and sulpharsenides as well as gold. Pyrite is the most common sulphide mineral in the gold deposits associated with volcanic rocks, and usually pyrrhotite in those associated with sedimentary rocks. The principal sulphide minerals in those connected with banded iron formations are pyrite and arsenopyrite. A separate group of formations consists of the palaeoplacer gold deposits associated with the molasse-like quartzites and conglomerates of Central Lapland. The iron oxide-copper-gold deposits of Central Lapland, which are a significant potential source of copper and gold, are mostly associated with skarn rocks at the eastern contact of the acidic intrusive rocks of Western Lapland and with skarn rocks occurring as interlayers in metavolcanic and metasedimentary rocks. The gold deposits that have led to actual mining activities in Central Lapland are Saattopora in Kittilä and Pahtavaara in Sodankylä. Apart from the Laurinoja iron oxide-copper-gold ore body in Kolari, copper concentrate has been produced from the Saattopora gold ore deposit and the Pahtavuoma copper ore deposit. Only one gold ore in Central Lapland is being actively exploited at present, that of the Pahtavaara mine, which was worked in 1995–2000 and reopened in 2003. The best starting point for successful gold ore exploration in Central Lapland can be achieved through a thorough knowledge of the deformation zones and their structures and alteration processes and the application of geochemical methods. Magnetic surveys can be of help in identifying and locating deformation zones of interest for exploration purposes and the majority of the associated shear zones and faults. Ore-critical zones usually feature graphite-bearing schists and iron sulphide-bearing sequences that can be traced by electrical methods and used as marker zones to verify the results of geological mapping. Geological, geophysical and geochemical techniques have been used in great diversity, and in particular till geochemistry and bedrock drilling have been methods by which the gold and copper deposits in Central Lapland have been discovered. A total of 7.6 million tonnes of gold and copper ores, including the Laurinoja iron oxide-copper-gold ore, were extracted in Central Lapland over the period 1982–2000. The resulting production of gold during this period was 10 800 kg, together with 21 000 tonnes of copper in concentrates and 4500 kg of silver. The gold and copper ores have been concentrated by gravity separation and/or flotation, since the ores so far taken into production has been of the free milling type. However, a substantial proportion of the deposits in the area contain copper, nickel, cobalt and arsenic as well, in the form of sulphides or sulpharsenides, so that the achievement of commercially saleable products calls for the use of different leaching processes. Deposits have also been found in Central Lapland that have consisted partly or entirely of refractory gold ore in which gold is lying in the crystal lattice of pyrite and/or arsenopyrite, the processing of which by the above-mentioned methods is not economic, as it requires pre-treatment by bio-oxidation or pressure oxidation in order to convert the gold to a cyanide-soluble form.

Cette thèse, financée dans le cadre du projet européen CSP2, porte sur l'étude d'un nouveau type de récepteur solaire thermique à concentration utilisant comme fluide caloporteur une suspension dense de fines particules en circulation ascendante dans des tubes verticaux. Ladite suspension est obtenue par fluidisation de particules de classe A. Le principe consiste à créer un écoulement ascendant de la suspension dans un tube vertical exposé au rayonnement solaire concentré qui chauffe la paroi du tube, qui transmet ensuite cette chaleur aux particules, qui la transportent jusqu'à un cycle de conversion d'énergie pour la production d'électricité. Au contraire des fluides solaires classiques, les particules peuvent atteindre les hautes températures (> 700 °C) permettant l'utilisation de cycles à haut rendement de conversion (Brayton, cycles combinés), tout en permettant un stockage direct de la pour une production continue. Au cours de la thèse, un récepteur à un tube a été testé avec succès au grand four solaire du laboratoire PROMES-CNRS à Odeillo, les particules en sortie atteignant 750 °C, ce qui a prouvé la faisabilité du concept et permis la détermination des premières valeurs de coefficient d'échange de chaleur tube-suspension. L'hydrodynamique de l'écoulement et les mécanismes d'échange de chaleur ont été observés grâce à des simulations numériques 3D. Un récepteur de 150 kWth à 16 tubes a ensuite été testé et modélisé, validant l'utilisation du procédé à plus grande échelle. / This thesis, financed in the frame of the CSP2 European project, concerns the study of a new kind of thermal concentrating solar receiver using a dense suspension of solid particles circulating upward in vertical tubes. The suspension is obtained by fluidizing Geldart A-type particles. The principle consists in creating an upward flow of the suspension in a vertical tube exposed to the concentrated solar radiation that heats the tube wall. The heat is then transmitted to the particles circulating inside that transport it to a conversion cycle for electricity production. Contrarily to usual solar heat transfer fluids, particles can reach high temperatures (> 700 °C) that permit to power high efficiency thermodynamic cycles such as Brayton or combined cycles. Moreover they can be used as a direct heat storage medium for continuous electricity production. During this thesis, a one-tube solar receiver was successfully tested at the PROMES-CNRS solar furnace in Odeillo, with particle outlet temperatures of 750 °C reached. The first values of wall-to-suspension heat transfer coefficient were calculated and a Nusselt correlation was determined. A specific flow pattern with a particle downward flux close to the wall and upward flux in the tube center was underlined. The flow hydrodynamics and the heat transfer mechanisms were studied thanks to 3D numerical simulations. A 16-tube 150 kWth receiver was finally tested and modeled, proving the process applicability at larger scale.