Thèses sur le sujet « CO2 vents »

Global warming and ocean acidification, due to rising atmospheric levels of CO2, represent an actual threat to terrestrial and marine environments. Since Industrial Revolution, in less of 250 years, pH of surface seawater decreased on average of 0.1 unit, and is expected to further decreases of approximately 0.3-0.4 units by the end of this century. Naturally acidified marine areas, such as CO2 vent systems at the Ischia Island, allow to study acclimatation and adaptation of individual species as well as the structure of communities, and ecosystems to OA. The main aim of this thesis was to study how hard bottom sublittoral benthic assemblages changed trough time along a pH gradient. For this purpose, the temporal dynamics of mature assemblages established on artificial substrates (volcanic tiles) over a 3 year- period were analysed. Our results revealed how composition and dynamics of the community were altered and highly simplified at different level of seawater acidification. In fact, extreme low values of pH (approximately 6.9), affected strongly the assemblages, reducing diversity both in terms of taxa and functional groups, respect to lower acidification levels (mean pH 7.8) and ambient conditions (8.1 unit). Temporal variation was observed in terms of species composition but not in functional groups. Variability was related to species belonging to the same functional group, suggesting the occurrence of functional redundancy. Therefore, the analysis of functional groups kept information on the structure, but lost information on species diversity and dynamics. Decreasing in ocean pH is only one of many future global changes that will occur at the end of this century (increase of ocean temperature, sea level rise, eutrophication etc.). The interaction between these factors and OA could exacerbate the community and ecosystem effects showed by this thesis.

Abstract The ubiquity of the Calvin-Benson-Bassham cycle (CBB) amongst autotrophic organisms suggests that it provides an advantage over a wide range of environmental conditions. However, in some habitats, such as hydrothermal vents, the reductive citric acid cycle (rCAC) is an equally predominant carbon fixation pathway. It has been suggested that the CBB cycle poses a disadvantage under certain circumstances due to being more energetically demanding compared to other carbon fixation pathways. The purpose of this study was to compare the relative metabolic cost of cell biosynthesis by an autotrophic cell using either the CBB cycle or the rCAC. For both pathways, the energy, in ATP, required to synthesize the macromolecules (DNA, RNA, protein, and cell envelope) for one gram of biomass was calculated, beginning with CO2. Two sulfur-oxidizing chemolithoautotrophic proteobacteria, Thiomicrospira crunogena XCL-2, and Sulfurimonas autotrophica were used to model the CBB cycle and rCAC, respectively while Escherichia coli was used to model both pathways because it has had its cell composition extremely well-characterized. Since these organisms have had their genomes sequenced, it was possible to reconstruct the biochemical pathways necessary for intermediate and macromolecule synthesis. Prior estimates, based solely on the ATP cost of pyruvate biosynthesis, suggested that the cellular energetic expense for biosynthesis from the CBB cycle was more than that from the rCAC. The results of this study support this conclusion; however the difference in expense between the two pathways may not be as extreme as suggested by pyruvate synthesis. Other factors, such as oxygen sensitivity, may act in concert with energetic expense in contributing to the selective advantages between different autotrophic carbon fixation pathways.

L’augmentation du CO2 atmosphérique conduit à des changements physiques et chimiques de l’océan. Les projections du GIEC selon le scénario à fortes émissions RCP8.5, suggèrent un réchauffement de la surface des océans de 3.2°C et une diminution de 0.3 unités de pH à la fin du siècle. Ces changements environnementaux s’accompagnent d’importantes conséquences sur les écosystèmes et les services rendus aux humains. La mer Méditerranée est un « hotspot » du changement global avec une prévision d’augmentation de la température de surface de la mer de +20% comparé aux projections globales, accompagné d’une augmentation d'événements extrêmes comme les vagues de chaleur marines. L’objectif principal de cette thèse est de déterminer les effets de la variabilité environnementale présente et future sur des coraux Méditerranéens. Des populations naturelles de coraux vivant au niveau d’évents de CO2 à Ischia (Italie) sont utilisées. Une acidification locale de l’eau de mer survient autour de ces évents, avec des valeurs de pH proches de celles qui sont attendues pour la fin du siècle. Les deux espèces étudiées : Cladocora caespitosa (zooxanthellé) et Astroides calycularis (azooxanthellé), ont une grande importance pour la conservation de part leur statut d’espèces fondatrices. Les principales questions de l’étude sont: (1) comment les conditions présentes et futures de températures et/ou de pH affectent la physiologie des deux espèces à différents stades de vie (adultes, gamétogenèse, larves et recrues) et (2) est-ce que l’exposition à un pH bas peut augmenter la tolérance des coraux face à une future acidification. Afin de répondre à ces questions, nous avons combiné l’analyse de données environnementales, l’étude sur le terrain et des expériences de laboratoire avec contrôle de température et de pH. Ma thèse se focalise en premier lieu sur la réponse des colonies adultes face au réchauffement de l’océan, avec l’acquisition des réponses physiologiques et le rétablissement des deux coraux à un réchauffement et à des vagues de chaleur marines simulées en laboratoire à partir de données réelles. Nous avons ensuite étudié, si l’exposition au pH bas des évents de CO2 procurait une tolérance à l’acidification chez les deux espèces. Cette thèse s’applique également à identifier l’impact du changement global sur la reproduction sexuelle et les premiers stades de vie des deux espèces de coraux. Dans un premier temps, j’ai étudié le développement et la croissance post fixation de larves d’A. calycularis face au réchauffement et à l’acidification. Puis, j’ai testé l’hypothèse selon laquelle des larves provenant des évents de CO2 présentaient une tolérance à l’acidification. L’expression des gènes entre les populations et les traitements de pH en laboratoire a également été étudiée. Enfin, une comparaison des gamètes de C. caespitosa provenant des évents de CO2 et d’un site ambient a été effectuée par analyse histologique afin de savoir si le pH a un impact sur la gamétogenèse et le ponte. Nos résultats suggèrent que les impacts du réchauffement et de l’acidification sur les colonies adultes de C. caespitosa et A. calycularis sont modérées, avec une tolérance à l’acidification et un rétablissement après les températures estivales. Par contre, l’impact sur les premiers stades de vie d’A. calycularis et la reproduction de C. caespitosa est inquiétant et pourrait compromettre le maintien des populations. Mes résultats suggèrent que C. caespitosa and A. calycularis vivants au niveau des évents de CO2 de Ischia, ne sont pas acclimatés à l’acidification de l’eau de mer. De plus, cette exposition à des pH bas affecterait la physiologie des individus et la croissance de la population. Étant donné la sensibilité des deux espèces de coraux au changement global, ma thèse souligne un risque de changement de composition des communautés méditerranéennes dans un futur proche et une urgence à établir des mesures de conservation et un suivi à long terme
The increase of atmospheric CO2 is driving changes in the ocean’s physical and chemical properties. The projections by the IPCC under the high CO2 emission scenario RCP 8.5 suggest global sea surface temperature warming of 3.2°C and a decrease in pH of 0.3 units by the end of the century. Such changes have important consequences for ecosystems and the services they provide to humans. The Mediterranean Sea is a hot-spot of global change with warming sea surface temperature projected to be 20% higher than global projections and an increase in extreme events such as marine heatwaves. The main goal of this thesis is to determine the effects of present and future coastal environmental conditions on Mediterranean corals. Natural populations of corals from two volcanic CO2 vents in Ischia (Italy) are used. Local acidification of seawater occurs around the vents with pH values close to those expected by the end of the century. This research is focused on two Mediterranean long-lived corals that have key relevance for conservation as habitat-forming species: the zooxanthellate Cladocora caespitosa and the azooxanthellate Astroides calycularis. The main research questions are: (1) how present-day and future warming and/or acidification affect the physiology of Cladocora caespitosa and Astroides calycularis at every life stage (adult, gametogenesis, larvae, and recruits) and (2) does previous exposure to low pH at CO2 vents enhance their tolerance to future ocean acidification. To answer these questions, we combined environmental data, ecological field surveys at CO2 vent sites and reference sites with ambient pH, and laboratory experiments with controlled temperature and pH. This thesis provides new insights into the responses of adult colonies to warming on. I assess the physiological impact and potential recovery to different warming scenarios and heatwaves events, based on nine years of temperature data collected at the study site. I then study whether past exposure to low pH conditions confers tolerance to ocean acidification on the two species, with colonies sampled at the CO2 vent and ambient pH sites and maintained in the laboratory under present day and low pH conditions. I also focus on sexual reproduction and early life stages of the two Mediterranean corals to better understand how they respond to ocean warming and acidification. First, I characterize the development and post-settlement growth of larvae of A. calycularis under high and ambient temperatures and ambient and low pH. I then take a closer look at tolerance to acidification by exposing larvae from the CO2 vents and ambient pH site to different pH conditions. I also explore whether differences in gene expression between the populations and pH treatments exist. Finally, I compare gametogenesis of C. caespitosa’s colonies from the CO2 vent and ambient sites through histological analysis to test the impact of low pH on gametogenesis and spawning. The results suggest that the impacts of warming and acidification on adult colonies of C. caespitosa and A. calycularis are moderate, with a tolerance to acidification and a recovery after summer heat. However, the impact of global change on the early life stages of A. calycularis and on the reproduction of C. caespitosa is worrying and could compromise the sustainability of the populations. My results suggest that C. caespitosa and A. calycularis living at the CO2 vents sites of Ischia are not acclimatized to ocean acidification. Furthermore, exposure to low pH at the vent sites impairs individuals’ physiology (reproduction, early life stages development, morphology of the colony) and population growth. Given the susceptibility of both species to global change, the results highlight the risk of changes in the composition of Mediterranean communities in the near future and the urge to establish general conservation measures and long-term monitoring

Il problema dell'acidificazione degli oceani, conseguente ai cambiamenti climatici, è un processo ancora poco conosciuto. Per comprendere questo fenomeno, possono essere utilizzati degli ambienti naturalmente acidificati, considerati laboratori a cielo aperto. Lo scopo di questo lavoro di tesi è stato quello di utilizzare le fumarole presenti nell'isola di Ischia, per approfondire le dinamiche dei processi di acidificazione e per analizzare l'eventuale interazione tra pH e condizioni meteorologiche. I dati utilizzati, forniti dalla Stazione Zoologica “Anton Dohrn” di Napoli, erano serie di pH e di vento rilevate in continuo, in due aree, nord e sud rispetto all'isolotto del Castello Aragonese, e in tre stazioni lungo un gradiente di acidificazione. Tutto il lavoro è stato svolto a step, dove il risultato di un'analisi suggeriva il tipo e il metodo analitico da utilizzare nelle analisi successive. Inizialmente i dati delle due serie sono stati analizzati singolarmente per ottenere i parametri più salienti delle due serie. In seguito i dati sono stati correlati fra loro per stimare l'influenza del vento sul pH. Globalmente è stato possibile evidenziare come il fenomeno dell'acidificazione sia correlato con il vento, ma la risposta sembra essere sito-specifica, essendo risultato dipendente da altri fattori interagenti a scala locale, come la geomorfologia del territorio, le correnti marine e la batimetria del fondale. È però emersa anche la difficoltà nel trovare chiare correlazioni fra le due serie indagate, perché molto complesse, a causa sia della numerosa quantità di zeri nella serie del vento, sia da una forte variabilità naturale del pH, nelle varie stazioni esaminate. In generale, con questo lavoro si è dimostrato come utilizzare tecniche di analisi delle serie storiche, e come poter utilizzare metodi di regressione, autocorrelazione, cross-correlation e smoothing che possono integrare i modelli che prendono in considerazione variabili esogene rispetto alla variabile di interesse.

Ce travail est une des premières tentatives d’utiliser une théorie non-Markovienne Energy- and Frequency-Corrected Sudden Approximation (EFCSA) pour construire la matrice de relaxation rotationnelle et modéliser des formes de bandes spectrales de gaz atmosphériques à haute pression. Nous avons généralisé les expressions déjà existantes pour la matrice de relaxation non-Markovienne pour le cas de deux molécules linéaires, ainsi prenant en compte la structure interne du perturbateur. Cette prise en compte est fondamentale pour une meilleure description des ailes spectrales lointaines, ce qui est essentiel pour la modélisation du transfert radiatif dans des milieux denses et dans l’atmosphère de Venus en particulier. Pour calculer cette matrice, il suffit de connaitre les fonctions de corrélation temporelles liées au mouvement translationnel, et nous proposons deux pistes directes pour les obtenir. La première utilise l’approche des moments spectraux. Nous avons obtenu des expressions analytiques pour les moments d’ordre 0 et 2 et testé la méthode sur des spectres Ramanroto-translationnels de N2 et CO2 purs. La seconde approche est basée sur le modèle Energy-Corrected Sudden (ECS). Nous avons donné des expressions qui prennent en compte la structure interne de la molécule perturbatrice et nous avons présenté un jeu de paramètres qui peuvent être ajustés surd es largeurs de raie expérimentales et utilisés par la suite pour calculer des spectres de gaz atmosphériques, y compris des spectres d’absorption de dioxyde de carbone à haute pression et haute température
This work presents one of the first attempts in using a non-Markovian Energy- and Frequency-Corrected Sudden Approximation (EFCSA) to build a rotational relaxation matrix and model spectral band shapes of atmospheric gases at highpressure. We have extended the existing expressionsfor the non-Markovian relaxation matrix to the case of two linear colliders, thus taking into account the internal structure of the perturber. This account is instrumental in a better description of the far spectral wings, which is essential for simulating the radiative transfer in dense media and, in particular, modeling of the Venus atmosphere. For the calculation of the matrix, it is sufficient to know translational time-correlation unctions, and we propose two straight forward ways to obtain them. The first one uses the spectral-moments approach. We have obtained analytical expressions for the 0th and 2nd moments and tested the approach forroto-translational Raman spectra of pure N2and CO2. The second approach is based onthe Energy-Corrected Sudden (ECS) model.We have outlined the expressions involving the second linear molecule and presented sets of parameters, which can be fitted on the experimental line widths and later used to predict the spectra of atmospheric species,including the absorption spectra of carbondioxide at high pressure and temperature

Neste trabalho é analisado o potencial eólico da região de Évora, tendo sido considerados quatro locais: Mitra, Portel, Reguengos e Colégio Verney. Com os dados de potência obtidos, foram escolhidas duas turbinas existentes no mercado, de potências nominais diferentes, para uma análise mais objectiva do real potencial da região. Apurou-se que, com a instalação de três turbinas menores, se obtém praticamente a mesma potência, por um preço consideravelmente inferior. Foi ainda possível verificar-se que a quantidade evitada de C02 para a atmosfera, ao considerar uma turbina de 5000 W (B) ou três 1000 W (A), é semelhante, concluindo-se que, considerando a eficiência, potencial, preço e emissões de co2 evitadas, a instalação de diversas turbinas A é a melhor opção. Este trabalho reveste-se de particular interesse considerando o facto de ser do conhecimento geral que, nas regiões costeiras e montanhosas, o potencial eólico está bastante estudado, ao passo que nas regiões interiores tal não acontece. ABSTRACT: ln this work, we assess the potential wind power in Évora, and four locations have been considered: Mitra, Portel, Reguengos and Évora. Based on the local wind power potential, two kinds of turbines were selected, for a more objective analysis of the region's useful wind power. It was found that the option for three small turbines allows the extraction of the same wind power that is extracted by the bigger turbine and at a considerably lower installation cost. lt was also found that the reduction in co2 emissions to the atmosphere, when considering the cases of one 5000 W (B) turbine and three 1000 W (A) turbines, is similar, therefore was concluded that, given the efficiency, potential, price and reduction of C02 emissions, the installation of several A turbines is the best option. This work is of particular interest because in coastal and mountain areas the wind potential is quite known, while this is not the case of inland areas.

Les objectifs environnementaux (COP21) visant à réduire les émissions de gaz à effet de serre et l'impact de l'industrie sur la nature, font face au défi de la demande croissante d'énergie et de produits. Les procédés chimiques sont les premiers en cause lorsqu’ils mettent en œuvre des solvants. L'ingénierie des solvants est une solution innovante qui vise à trouver des milieux alternatifs bénins possédant les propriétés de solvant adaptés pour chaque étape du procédé.Dans cette perspective, nous avons étudié les Liquides expansés par un gaz (LEGs), qui sont desliquides dont le volume augmente sous l’effet d’un gaz dissous sous pression. En particulier, le CO2 peut être utilisé comme agent d'expansion pour obtenir des liquides expansés par du CO2(LECs), combinant les avantages du CO2 et du solvant. La phase expansée peut contenir des concentrations élevées de CO2, jusqu'à 80%, selon le solvant, ce qui conduit à une réduction du besoin du solvant organique, mais aussi à des changements des propriétés physicochimiques et de transport de la nouvelle phase expansée. On peut de plus moduler ces propriétés par la pression et la température, d'une manière réversible, et améliorer la séparation des produits. Dans cette étude, différents solvants biosourcés ont été utilisés pour obtenir des systèmes expansés par du CO2, tels que les acétates d'alkyle, les carbonates organiques, les méthoxybenzènes, etc.La connaissance des équilibres de phase, des propriétés de solvatation et de transport est essentielle pour concevoir des processus qui exploitent le comportement particulier de ces systèmes biphasiques. Deux approches principales ont été utilisées pour caractériser ces systèmes. Dans un premier temps, des mesures ont été effectuées dans une cellule à haute pression et à volume variable pour évaluer la polarité au travers du paramètre Kamlet-Taft (KT) *(dipolarité / polarisabilité) dans les solvants expansés par du CO2 sous des pressions allant jusqu'à 30 MPa. La technique utilisée a été la spectroscopie UV-Vis suivant le déplacement hypsochromique du Rouge de Nile, une sonde solvatochromique déjà utilisée pour obtenir les paramètres KT dans des solvants purs. De plus, des mesures d'équilibre vapeur-liquide (ELV) ont été effectuées pour obtenir la composition de la phase expansée à différentes pressions et températures afin de comprendre la solvatation du CO2 dans les solvants organiques et de fournir des informations manquantes dans la littérature. En deuxième lieu, dans une approche plus théorique, les données ELV ont été utilisées pour calculer numériquement d'autres propriétés telles que la densité et la viscosité. Des équations d'état et des simulations par dynamique moléculaire (DM) ont été utilisées ; ces dernières donnant de meilleurs résultats dans un mode prédictif de la masse volumique et permettant de suivre les positions moléculaires au cours du temps, qui peut être liée à de nombreuses propriétés, y compris la viscosité étudiée ici. Ces calculs ont été effectués en utilisant un champ de force de type Amber adapté. Les résultats obtenus dans l’ensemble complètent les données de la littérature existante et apportent de nouvelles informations sur les propriétés des LEGs. Par exemple, le comportement non linéaire de l'expansion volumétrique, vérifié après les déterminations de masse volumique sur les simulations DM à l'équilibre, est une clé dans la compréhension des interactions soluté-solvant ; ainsi que les valeurs KT * obtenues qui confirment la large gamme de polarité couverte par ces systèmes.Enfin, certains systèmes expansés par du CO2 ont été utilisés pour produire des nanoparticules de TiO2 pour panneaux solaires, améliorant leur surface spécifique et donc leur efficacité en tant que semi-conducteurs ; et d’autres ont été appliqués à un processus d'activation enzymatique entraînant une augmentation significative du taux de conversion

The main aim of this thesis was to determine how marine metazoans might persist as ocean acidification (OA) conditions intensify. This was done using a combination of field surveys, field transplants and laboratory experiments with polychaetes from a site where volcanically-derived CO2 gas bubbles through the seafloor and drives the seawater pH down, resulting in a marine ecosystem representative of global OA projections for, or before, the year 2100. My first objective was to identify phenotypes, or traits, associated with OA tolerance (Chapter 2 and 5). To do this, I characterized the distribution of dominant calcifying polychaetes along natural pH gradients and used a comparative species recruitment trial to investigate life history traits underlying species’ OA tolerance, or vulnerability. I first found two dominant, closely related species of polychaete: Pileolaria militaris Claparède, 1870 and Simplaria sp. (Serpulidae, Spirorbinae). I then found that increased fecundity and rapid settlement are important traits in determining species’ abilities to persist in low pH environments (Chapter 2). Afterwhich, I investigated the life history traits of the non-calcifying polychaete, Platynereis dumerilii (Audouin & Milne Edwards, 1834), of one of the few species from the low pH site known to have broadcasting, pelagic development. I performed breeding experiments on P. dumerilii collected in both ambient and low pH sites and found that specimens from the low pH site were actually the direct developing brooder sister species, Platynereis massiliensis (Moquin-Tandon, 1869). By reanalayzing the distributions of both species at each site using genetic barcoding, I found clear evidence that direct development and brooding are dominant traits at low pH site, and for OA persistence (Chapter 5). My second objective was to use reciprocal transplant experiments to compare the relative importance of local adaptation and/or plasticity as potential mechanisms responsible for the differential tolerances of populations of the polychaete species Simplaria sp. to low pH. Laboratory transplants indicate that a local adaptation response occurred through genetic accommodation in the Simplaria sp. population from the low pH site. However, neither local adaptation nor plasticity appeared responsible for this species natural low pH persistence when assessed in situ (Chapter 3 & 4). My final objective was to create a framework using the polychaete vent model to identify other types of marine metazoans that are likely to be able to adapt to, and survive, under the predicted environmental conditions (Chapter 5). I overviewed the life history strategies of all dominant polychaetes in the low pH sites, and related trends in their life history strategies to those of other marine invertebrates. Brooding and direct development appear to be key traits for species likely to persist in future oceans pH. I conclude by summarizing how research regarding evolutionary responses may be advanced to add confidence to our projections of future marine metazoan responses.

L’objectif de ce travail de thèse a été d’évaluer les propriétés inhibitrices de corrosion d’un traitement multifonctionnel utilisé dans l’industrie pétrolière. Dans la première partie de la thèse, l’influence des conditions hydrodynamiques, du temps d’immersion et de la température sur les processus de corrosion de l’acier API 5L-X65 en milieu CO2 en l’absence d’inhibiteur a été étudiée par des mesures électrochimiques (courbes de polarisation, courbes de Levich et spectroscopie d’impédance électrochimique) avec une électrode à disque tournant. A partir de ces essais, la vitesse de corrosion a été calculée pour les différentes conditions expérimentales. L’analyse couplée des résultats électrochimiques et des analyses de surface suggèrent la formation d’une couche de produits de corrosion, principalement de carbonate de fer qui recouvre la surface du métal et conduit à la diminution de la vitesse de corrosion quand le temps d’immersion, la vitesse de rotation et la température augmentent. La deuxième partie de la thèse a été consacrée à l’évaluation d’un traitement multifonctionnel contre la corrosion. Ce traitement est composé principalement de produits extraits de l’Aloe Vera (gel de l’Aloe Vera et « acibar »). Ces produits ont été choisis car ils empêchent la formation simultanée d’hydrates et de carbonate de calcium. Ces composés « verts », ainsi que la dodécylamine, qui est un inhibiteur de corrosion commercial, ont été testés à l’aide des mesures électrochimiques et par perte de masse afin de comparer leur efficacité et d’évaluer un possible effet de synergie lorsqu’ils sont utilisés en mélange. Les produits testés séparément ont un pouvoir protecteur comparable et il n’a pas été mis en évidence d’effet de synergie. En revanche, il a été montré que les composés sont compatibles entre eux. Ceci constitue un point très important pour l’utilisation de ces traitements qui permettent d’augmenter la fiabilité et la rentabilité pour la production du pétrole et du gaz
The objective of this work was to evaluate the corrosion inhibitive properties of a multifunctional treatment used in the petroleum industry. In the first part of the thesis, the influence of hydrodynamic conditions, immersion time and temperature on the corrosion process of API 5L-X65 steel in CO2 medium in absence of inhibitor was studied by electrochemical measurements (polarization curves, Levich curves and electrochemical impedance spectroscopy) with a rotating disk electrode. From these tests, the corrosion rate was calculated for different experimental conditions. The analysis of the electrochemical results and surface analyses suggest the formation of a layer of corrosion products, mainly iron carbonate which covers the metal surface and leads to the decrease of the corrosion rate when the immersion time, the rotation speed and temperature increase. The second part of this work was devoted to the evaluation of a multifunctional treatment against corrosion. The treatment is mainly composed Aloe Vera extracts (Aloe Vera gel and "acibar”). These products were chosen because they prevent the simultaneous formation of hydrates and calcium carbonate. These "green" compounds and dodecylamine, which is a commercial corrosion inhibitor, were tested using electrochemical measurements and by mass loss in order to compare their efficiency and to evaluate a possible synergistic effect when they are used as a mixture. The products tested separately have a similar efficiency and did not reveal any synergistic effect. However, it was shown that the compounds are compatible. This is an important point for the use of these treatments which can increase the reliability and profitability for the production of oil and gas

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Nesta pesquisa apresenta-se o desenvolvimento de uma metodologia híbrida utilizando a rede neural artificial perceptron multicamadas e os modelos estatísticos ARIMA com a abordagem de Box e Jenkins, com o objetivo de prever séries temporais de velocidade dos ventos. Os modelos estatísticos ARIMA realizam a previsão das séries de dados, que ainda conservam os padrões não lineares, juntamente com a rede MLP e o algoritmo de aprendizagem retropropagação que, através do erro de previsão obtido, desenvolvem um Modelo Híbrido aditivo para previsão de séries temporais. Os testes de validação foram realizados com dois bancos de dados de séries de velocidade dos ventos. No Teste 1 os dados foram fornecidos de um banco de dados agrometereológicos localizado na região de Ilha Solteira - SP, e no Teste 2 os dados são oriundos de um projeto desenvolvido pelo INPE (Instituto Nacional de Pesquisas Espaciais) que fornece dados anemométricos e solarimétricos em alturas de 25 e 50 metros, possuindo bases em várias regiões do Brasil. Analisando os erros médios quadráticos (MAPE) conclui-se que estão dentro dos limites encontrados na literatura
This work presents a hybrid methodology using MLP (multilayer perceptron) neural network and statistical ARIMA of Box and Jenkins to predict wind time series. The ARIMA models predict the time series data that are nonlinear, and the error obtained is introduced in the MLP by backpropagation training, forming the hybrid additive model. Tests were done with two data sets. Test 1 uses data from Ilha Solteira, SP region developed by an Agrometheorogical project of UNESP Campus of Ilha Solteira. Test 2 the data are from a project developed by INPE (National Space Research Institute) which provides solar and wind data in adequate high to energy generation in several regions of Brazil. Results are analyzed by MAPE (mean absolute percent error) and are in accordance with those found in the specialized literature

Orientador: Anna Diva Plasencia Lotufo
Co-orientador: Mara Lúcia Martins Lopes
Banca: Lilian Yuli Isoda
Banca: Alessandra Bonato Altran
Resumo: Nesta pesquisa apresenta-se o desenvolvimento de uma metodologia híbrida utilizando a rede neural artificial perceptron multicamadas e os modelos estatísticos ARIMA com a abordagem de Box e Jenkins, com o objetivo de prever séries temporais de velocidade dos ventos. Os modelos estatísticos ARIMA realizam a previsão das séries de dados, que ainda conservam os padrões não lineares, juntamente com a rede MLP e o algoritmo de aprendizagem retropropagação que, através do erro de previsão obtido, desenvolvem um Modelo Híbrido aditivo para previsão de séries temporais. Os testes de validação foram realizados com dois bancos de dados de séries de velocidade dos ventos. No Teste 1 os dados foram fornecidos de um banco de dados agrometereológicos localizado na região de Ilha Solteira - SP, e no Teste 2 os dados são oriundos de um projeto desenvolvido pelo INPE (Instituto Nacional de Pesquisas Espaciais) que fornece dados anemométricos e solarimétricos em alturas de 25 e 50 metros, possuindo bases em várias regiões do Brasil. Analisando os erros médios quadráticos (MAPE) conclui-se que estão dentro dos limites encontrados na literatura
Abstract: This work presents a hybrid methodology using MLP (multilayer perceptron) neural network and statistical ARIMA of Box and Jenkins to predict wind time series. The ARIMA models predict the time series data that are nonlinear, and the error obtained is introduced in the MLP by backpropagation training, forming the hybrid additive model. Tests were done with two data sets. Test 1 uses data from Ilha Solteira, SP region developed by an Agrometheorogical project of UNESP Campus of Ilha Solteira. Test 2 the data are from a project developed by INPE (National Space Research Institute) which provides solar and wind data in adequate high to energy generation in several regions of Brazil. Results are analyzed by MAPE (mean absolute percent error) and are in accordance with those found in the specialized literature
Mestre

Este trabalho descreve o desenvolvimento de um sistema de controle com compensação de tempo morto aplicado a um ventilador para simular os efeitos do vento em modelos de embarcações. O sistema é instalado no tanque de provas do Departamento de Engenharia Naval da Escola Politécnica da USP. Um sistema de controle baseado em computador é elaborado para a realização dos testes e validação, procedendo-se inicialmente a identificação do sistema a ser controlado. Na malha de controle, o sinal de referência é a velocidade do vento desejada em uma distância pré-definida do ventilador e pode ser tanto um valor constante (representando um vento constante) ou um valor variante no tempo (representando uma rajada de vento). O sistema atuador consiste de um inversor de frequência que aciona o ventilador e a velocidade do vento é medida por um anemômetro, cujo sinal é usado como realimentação para o controlador. A sintonia da malha é realizada pelo método do modelo interno (IMC) e o efeito do tempo morto é observado nos testes, aplicando-se o compensador baseado no Preditor de Smith para minimizá-lo. Pelos resultados dos ensaios, conclui-se que o Preditor de Smith melhora o desempenho do sistema de geração de vento.
This paper describes the development of a control system with dead time compensation applied to a fan to simulate wind effects in models of vessels. The system is installed on the academic towing tank of the Naval Architecture and Oceanic Engineering Department of the University of São Paulo. A control system based on computer is designed for testing and validation, proceeding initially to identify the system to be controlled. In the control loop, the set-point is the desired speed of the wind on a pre-defined distance from the fan and it can be either a constant value (representing a constant wind) or a time-varying value (representing a wind gust). The actuator system consists of a frequency-inverter that drives the fan and the wind speed is measured by an anemometer, whose signal is used as feedback to the controller. The tuning of the controller is made by the internal model control (IMC) and the effect of dead time is observed in the tests, applying the compensator based on Smith Predictor to minimize it. Through the results from the tests, it was concluded that the Smith Predictor improves the performance of the wind generation system.

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The time of flight method for determining the wind speed using ultrasonic transducers is presented in this work. The techniques of phase difference and threshold detection for determining the time of flight are presented. A more detailed study of the phase difference technique is carried out in order to determine the design specifications using this method with respect to the noise sensitivity, dependence of the measurement range with the medium temperature and measurement resolution. A design specification example is presented in order to illustrate the proposed procedures.
Apresenta-se neste trabalho o método do tempo de trânsito para determinação da velocidade do vento utilizando transdutores ultra-sônicos. Apresentam-se as técnicas da diferença de fase e detecção de limiar para determinação do tempo de trânsito deste método. Um estudo mais aprofundado é realizado para o método da diferença de fase de forma a determinar as especificações de projeto usando esse método, com relação à sensibilidade ao ruído, dependência da faixa de medição com temperatura do meio e resolução de medição. Um exemplo de especificação de projeto é apresentado de forma a ilustrar os procedimentos desenvolvidos.

As pesquisas modernas em aeronáutica envolvem a expansão dos envelopes de vôo, como resultado do desejo de melhorar a manobrabilidade e controlabilidade em operações táticas, e melhorar a segurança do vôo. Esses objetivos podem ser alcançados através do desenvolvimento de sistemas automáticos de controle de vôo. Os sistemas de controle aplicados a aeronaves podem ser desenvolvidos e simulados através de métodos computacionais. No entanto, existem imperfeições na simulação computacional por não se conseguir reproduzir algumas características do vôo real ou devido a simplificações no modelo matemático da aeronave. Desta forma, a construção de um modelo físico de uma aeronave em escala reduzida e a implementação de um controlador a este modelo, torna-se uma ferramenta bastante importante para validar resultados teóricos e métodos computacionais. Os custos associados a estes testes são geralmente muito menores que aqueles dos ensaios em vôo e com maior flexibilidade de instrumentação. Este trabalho descreve a construção de um modelo de aeronave, baseado no X-29, o desenvolvimento de um mecanismo de fixação do modelo ao túnel de vento, tipo rótula, e a implementação de um sistema de aumento de estabilidade longitudinal, através de um sistema de controle automático. O modelo físico possui uma configuração de asa com enflechamento negativo e canard, e que tende a ser inerentemente instável, sendo necessário o auxílio de um sistema de aumento de estabilidade. Testes de estabilidade dinâmica em arfagem foram realizados no túnel de vento em diferentes posições do centro de gravidade. Os parâmetros de estabilidade foram registrados e analisados através de uma curva de ajuste exponencial.
Modern aeronautical research involves flight envelope expansion as the result of a desire for improvement in tactical operation handling qualities and improvement in flight safety. These objectives can be achieved through the development of automatic flight control systems. Aircraft flight control systems can be developed and simulated through computational methods. However, there are imperfections in the computational simulation of flight dynamics due to the difficulty in reproducing real flight conditions or due simplifications in the aircraft mathematical model. The construction of a reduced scale physical aircraft model and the implementation of a controller is a very valuable tool to validate theoretical results and computational methods. The costs associated with these tests are usually much smaller than those associated with full scale flight testing and may offer greater flexibility for instrumentation. The present work describes the construction of an airplane model, based on the X-29, the development of a wind tunnel gimbal type support and the implementation of a longitudinal stability augmentation system using automatic flight control. The model configuration has forward swept wings and canard with a tendency to be inherently unstable and, thus, requiring a stability augmentation system. Pitching dynamic stability tests where conducted in a wind tunnel in different center of gravity positions. Stability parameters were acquired and analyzed by exponential fit curve.

Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.
Committee Chair: Kohl, Paul; Committee Member: Fuller, Tom; Committee Member: Gray, Gary; Committee Member: Liu, Meilin; Committee Member: Meredith, Carson; Committee Member: Rincon-Mora, Gabriel.

Desde o início da década de 2010, o aumento do preço do combustível de aviação e a pressão da sociedade para redução da emissão de gases nocivos ao meio ambiente, junto com a necessidade de redução de ruído durante as fases de decolagem e pouso, levaram as companhias aéreas a buscar aeronaves mais eficientes. Para suprir essa demanda, os fabricantes de aviões comerciais solucionaram esse problema através do uso de motores de maior desempenho, que apresentam maior diâmetro que motores de gerações passadas. Desse modo, foi necessário projetar asas com maior diedro na região da raiz, possibilitando a instalação desses novos motores, e diedro menor após a seção do motor, adotando assim a solução de asa em gaivota. O presente trabalho visa analisar o impacto de diferentes tipos de asas em gaivota nos coeficientes aerodinâmicos de uma aeronave de configuração comercial típica. Para tanto, foi realizada uma revisão bibliográfica dos estudos envolvendo asas em gaivota. Numa primeira fase foi feito um estudo analítico das características aerodinâmicas de alguns modelos de aeronaves com asa em gaivota, e em uma segunda fase, foram empregadas ferramentas computacionais para analisar seus comportamentos aerodinâmicos. Posteriormente, em uma terceira fase, esses modelos foram ensaiados no túnel de vento do LAE (Laboratório de Aerodinâmica da EESC/USP), e os resultados das três fases foram comparados.
Since the beginning of the 2010s, the increasing price of aviation fuel and the pressure of society to reduce the emission of harmful gases into the environment, coupled with the need of noise reduction during the takeoff and landing, induce carrier companies to look for more efficient airplanes. To furnish this demand, the airplane manufacturers solved the problem using high performance engines, which present a larger diameter than the engines from previous generations. Thereby, it was necessary to project wing with higher dihedral on the root portion, enabling the installation of these new engines, and a lower dihedral after the engine section, thus adopting a gull wing solution. This research project aims at analyzing the impact of different types of gull wing on the aerodynamic coefficients of a typical commercial configuration airplane. For this purpose, a bibliographic review about the studies related to gull wings was performed. In a first phase, an analytical analysis of the aerodynamic characteristics of some airplane model with gull wings was done, and in a second phase, computational programs was used to study their aerodynamic behavior. Later, in a third phase, these models were tested in the wind tunnel of LAE (Laboratory of Aerodynamics of EESC/USP), and the results from the three phases were compared.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Gene flow is a determining component of persistence and adaptation of local populations, and may influence their ecological properties. Understand the behavior of this flow in natural or altered populations is essential for developing effective conservation plans by the use of natural resources. We investigated the influence of Pinus plantations in the pollen dispersal patterns in remaining Araucaria angustifolia populations (patches), using paternity analysis with eight microsatellite locos. For this, we sampled two patches in the grassland area and two patches in the pine plantations area, located in southern Santa Catarina plateau. In the study areas all male reproductive individuals (68) and 400 seeds from 20 seed-tree (five per population) were mapped and genotyped. The paternity analysis revealed higher average distance of pollination for grassland area (170 m) than Pinus plantation area (67 m). The effective number of pollen donors (Nep) was 16.4 and 8.9 for grassland area and Pinus, respectively. Grassland areas showed a pollen immigration rate of 46%, and the plantation area showed a 36%. These results are an indication that the Pinus plantation can act as barrier to pollen flow, although, pollen dispersal occurs through plantings. There was no significant spatial genetic structure for adults, and high levels of genetic diversity were verified in both areas (He, ranging 0.16 to 0.829), with no significant differences, suggesting presence of historic gene flow between locals. While the seeds from natural grasslands seed-tree present no significant fixation index, the seeds from seed-tree located into Piuns plantations presented significant fixation indexes (F = 0.076, P<0.05). Both adult population and seeds showed private alleles, evidencing that not all possible reproductive individuals, in the remnants, contributed to seed sampled formation, however, pollen flow from outside contributed effectively to seed formation within patches
O fluxo gênico é um dos componentes determinantes da persistência e adaptação das populações locais, podendo influenciar em suas propriedades ecológicas. Entender o comportamento desse fluxo em populações naturais ou alteradas é essencial para elaboração de planos eficazes de conservação pelo uso dos recursos naturais. Investigou-se a influência de plantios de Pinus no padrão de dispersão de pólen em populações remanescentes de Araucaria angustifolia (capões), por meio análises de paternidade com oito locos microssatélites. Para isso, amostraram-se dois capões em área de campo e dois em área de plantios de Pinus, localizados no planalto sul catarinense. Nas áreas de estudo (capões) foram mapeados e genotipados todos os 68 indivíduos machos reprodutivos e mais 400 sementes retiradas de 20 plantas matrizes (cinco por população). A análise de paternidade revelou que a distância média de polinização para a área de campo (170 m), foi maior do que para área de plantios de Pinus (67 m). O número efetivo de polinizadores (Nep) foi de 16,4 e 8,9 para área de campo e plantio de Pinus, respectivamente. Áreas de campo apresentaram uma taxa de imigração de pólen de 46% e áreas de plantio apresentaram 36%. Esses resultados são um indicio de que os plantios de Pinus podem agir como barreira ao fluxo de pólen, embora ainda ocorre fluxo através dos plantios. Verificou-se a presença de estrutura genética espacial não significativa para os indivíduos adultos em ambas as áreas, além de uma elevada diversidade genética (He, variando de 0,16 a 0,829), sem diferenças significativas, sugerindo a presença de um fluxo gênico histórico entre as áreas. Enquanto as sementes oriundas das matrizes em meio as áreas de campo não apresentaram índice de fixação significativos, as sementes oriundas das árvores em meio aos plantios de Pinus apresentarem índices de fixação significativos (F = 0,076, P<0,05). Tanto a população adulta quanto as sementes apresentaram alelos exclusivos, evidenciando que nem todos os indivíduos reprodutivos presentes nos remanescentes contribuíram para a formação da amostra de sementes, entretanto o fluxo de pólen externo contribuiu efetivamente para formação das sementes de dentro do capão

Dissertação de mestrado, Biologia Marinha, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2015
Atmospheric CO2 concentrations have increased by at least 30% since pre-industrial times due to human activities. Part of this CO2 has been absorbed by oceans, inducing ocean acidification and, therefore, several impacts in the marine biota. Natural shallow-water CO2 vents have generated a substantial interest in recent years as in situ laboratories for ocean acidification studies. The present study was focused on the effects of ocean acidification on mesozooplankton communities. Two active volcanic areas with submarine CO2 emissions, in the islands of São Miguel and Faial, were chosen and independently studied, through the choice of three different sites: Reference, Intermediate and Vent, characterized for their increase in the CO2 degassing activity, and consequent pH decrease. Differences in the abundance, diversity and structure of mesozooplankton among sites were described, along with the characterization of the community in these areas, since previous information is scarce. Differences were found in the composition of the zooplanktonic assemblages among sites in São Miguel and among dates in Faial. Through the nMDS analyses, Radiozoa, Paracalanus parvus and Evadne spinifera appeared more related to vent conditions, while Cirripedia nauplii were closer to the reference conditions. Conditions in Faial did not allow a clear separation among sites in the nMDS analyses, since the strong currents mix the water, dissipating the effect of the gas emissions, and variation among days becomes more important and statistically significant. The RNA:DNA ratio of selected mesozooplankton populations was used, as proxies for physiological condition. RNA:DNA did not show a clear pattern of variation, copepods in São Miguel and cladocerans in Faial had an higher ratio in the reference sites, but with no gradual decrease to the Vent. Fish eggs seem to have an inverted pattern. Additional experiments conducted under natural conditions were performed to determine the egg production rate (EPR) of the dominant free-spawning copepod species, as a proxy for secondary production. In São Miguel, the EPR showed a decreasing trend along the CO2 gradient, with no differences between the exposure times. In Faial, EPR was higher in the reference, but it did not differ significantly from the other sites. This study demonstrated the suitability of the submarine degassing sites in S. Miguel and Faial Islands for investigating the effect of future dissolved CO2 levels in planktonic and pelagic communities of the NE Atlantic. It also provided the first in-situ evidence of a significant decrease of EPR of copepods under near future CO2 levels.
Desde os tempos pre-industriais que se registou um incremento do CO2 atmosférico, de pelo menos 30% devido a atividades humanas, principalmente pelo uso de combustíveis fósseis. Os oceanos têm absorvido parte deste CO2 através da sua capacidade de “sumidouro de carbono”, induzindo mudanças na composição química da água do mar (acidificação do oceano), com potenciais impactos nos organismos marinhos. As possíveis consequências ecológicas deste processo têm motivado um incremento no esforço de investigação nos últimos anos. A maioria dos efeitos nos organismos marinhos tem sido observada em experiências no laboratório, onde o CO2 é manipulado em escalas temporais curtas. Não obstante, a necessidade de usar diferentes abordagens, como experiências de campo, em ambientes marinhos específicos que contenham comunidades, mais do que espécies isoladas, tornou-se evidente. Locais de desgaseificação natural de CO2 em águas pouco profundas têm gerado um interesse substancial como laboratórios in situ para estudos de acidificação do oceano. Alterações significativas na estrutura da comunidade bentónica têm sido associadas com estes locais de desgaseificação, mas os efeitos no plâncton permanecem largamente desconhecidos. O presente estudo analisou os efeitos da acidificação do oceano nas comunidades de mesozooplâncton. Os objetivos especificos foram (i): o estudo observacional sobre as comunidades zooplanctónicas, para determinar se existem diferenças consistentes na abundância, diversidade e composição entre os locais afetados por emissões de CO2 e os locais de controlo, sem emissões; e (ii) a relação entre os padrões observados no zooplâncton em relação aos resultados detetados na química da água do mar e do gás das emissões, (iii) a descrição do estado ecofisiológico de grandes grupos de zooplâncton utilizando índices derivados dos ácidos nucleicos e índices de produção de ovos e a sua relação com o possível stress causado pela acidificação. Para atingir estes objetivos foram seleccionadas duas áreas vulcânicas activas, com emanações de CO2 submarinas, uma na ilha de São Miguel e outra na ilha de Faial, no arquipélago dos Açores. Cada ilha foi independentemente estudada, através da escolha de três lugares diferentes: Reference, Intermediate e Vent, ao longo de um gradiente na emissão de CO2, e consequente diminuição de pH. O pH em São Miguel variou de 8.06 no Reference (pCO2 383.80 μatm) a 7.75 no Vent (pCO2 983.10 μatm), enquanto que no Faial diminuiu de 8.13 no Reference (pCO2 319.37 μatm) a 7.88 no Vent (pCO2 894.08 μatm). O CO2 foi o principal constituinte das emissões de gás nas duas ilhas (acima de 98%), minimizando o efeito de outros gases como H2S. Em São Miguel o mesozooplâncton foi amostrado usando arrastos oblíquos com uma rede WP2 de Ø60cm e malhagem de 200 μm, entre os dias 3 e 7 de Julho de 2014, enquanto que no Faial foi usada uma rede com malhagem de 500μm e a amostragem foi feita entre os dias 10 e 15 de Julho de 2014. Foram descritas as diferenças na abundância, diversidade e estrutura do mesozooplâncton entre locais, em paralelo com a caracterização das comunidades nestas áreas, já que a informação prévia era escassa. Foram identificados organismos de nove filos, num total de 71 taxa diferentes, 45 em S. Miguel e 61 no Faial. Em São Miguel foram encontradas diferenças entre locais na abundância total e nas abundâncias de Arthropoda e Chordata, com um incremento no Vent, relativamente ao Intermediate e o Reference. No Faial foram apenas encontradas diferenças na diversidade dos Arthropoda. A análise PERMANOVA ilustrou as diferenças na composição do zooplâncton entre locais, em São Miguel, e entre datas, no Faial. Os principais contribuintes para estas diferenças, realçados pelas anaáises SIMPER, foram Evadne spinifera, Paracalanus parvus, nauplios de Cirripedia e Radiozoa. Através das análises nMDS, Radiozoa, Paracalanus parvus e Evadne spinifera apareceram mais relacionados às condições do Vent, enquanto que nauplios de Cirripedia estiveram mais perto das condições do Reference. No Faial, os principais contribuintes foram Bassia bassensis, Radiozoa e efiras de Scyphozoa. As condições nesta ilha não permitiram uma separação entre locais nas análises nMDS, dado que as fortes correntes misturaram a coluna de àgua, dissipando o efeito das emissões de gases, e a variação entre dias é aparentemente mais importante e estatisticamente significativa. O racio RNA:DNA de populações de mesozooplâncton seleccionadas foi usado como indicador da condição fisiológica. O RNA:DNA não mostrou um padrão claro de variação: Copepoda em São Miguel e Cladocera no Faial apresentaram valores mais elevados no Reference, mas este não diminuiu de forma gradual ao longo do gradiente de CO2. Os ovos de peixe parecem ter um padrão invertido. Experiências adicionais foram levados a cabo para determinar a taxa de produção de ovos (EPR) das espécies dominantes de copépodes, como indicador da produção secundária. As câmaras de incubação foram colocadas perto do fundo durante períodos de 24 e 72h em São Miguel, e 72h no Faial. Em São Miguel, a EPR mostrou uma tendência de diminuição ao longo do gradiente de CO2, sem diferenças nos tempos de exposição. No Faial, EPR foi maior no Reference, mas não diferiu significativamente dos outros locais. Este estudo demonstrou o potencial das zonas de desgaseificação submarina nas ilhas de S. Miguel e Faial para a investigação dos efeitos dos níveis futuros de CO2 dissolvido nas comunidades planctónicas e pelágicas do Atlântico NE. Este trabalho também permitiu registar a primeira evidência in-situ de uma diminuição significativa da produção secundária em copépodes sob concentrações de CO2 previstas para o final do século.

The motivation for this work is the weak level of confidence in forecasting the temperature profile for the Martian atmosphere over the aerobraking region. This limitation comes mainly because of a misrepresentation of the atomic oxygen distribution in atmospheric models, which is a result of lack of measurements. One effective way to observe atomic oxygen and temperature remotely in the 50 to 100 km altitude region is through airglow measurements. The first part of the thesis involves the development of an airglow model to simulate four O2 emissions: the Herzberg I, Herzberg II, and Chamberlain band systems, as well as the Infrared Atmospheric emission at 1.27 um. The model predictions are compared with available observations from both the Mars and Venus atmospheres to exploit the consistency in the photochemistry of these two CO2-dominated atmospheres. Using composition from 3-D global circulation models of the Mars and Venus atmospheres, simulations are performed with realistic dynamical variations. Previous studies used 1-D photochemical models only. Hence, this novel approach allows in-depth investigation of the influence of dynamics and circulation on the airglow behaviour. A sensitivity study is conducted to understand the impact of the different photochemical parameters available in the literature and to recommend a set of parameters to be used in future model predictions. This approach also provides an understanding of the impact of atmospheric conditions, like temperature, dust load, water concentrations, etc., on the vertical structure of the emissions. A retrieval algorithm is also developed to perform a partial inversion of the recorded signal to extract the NO airglow emission in the Mars atmosphere from the SPICAM instrument. The method is tested with one year of stellar occultation measurements and validated with observations from SPICAM in a limb-viewing geometry and with airglow model predictions. This work identified and quantified, for the first time, localised variations in the NO nightglow, providing insights into the factors influencing the distribution of the oxygen species other than the general circulation and the photochemistry. The method proved to be a useful tool to build a climatology of the NO emission in the Mars atmosphere.

碩士
國立清華大學
化學工程學系
103
Greenhouse effect main reason for the significant increase in global average temperatures since the industrial revolution. Greenhouse effect is most likely one of the reasons for the extensive use of fossil fuels so that the CO2 concentration in the atmosphere increased significantly. In order to suppress the rise in CO2 concentration, Energy saving and carbon reduction have become the key projects of the National Energy Policy Development Environment. For this purpose, we build a carbon capture system in steel plant and laboratory. As a basis for the application of various absorbents related research, and provide process improvement methods to achieve energy savings. The study capture CO2 by 30wt% MEA solution and 4mPZ+4mDETA solution that was carried out in rotating packed bed connected gas stripper. The conventional packed bed absorber and stripper were replaced by a rotating packed bed for reducing the volumes of conventional packed bed absorber and stripper and the regeneration energy of chemical absorbent in CO2 capture process. Developed as a result of gravity rotating bed can improve the gas-liquid contact surface area. In the study, compared with conventional packed bed and rotating packed bed for CO2 capture efficiency at same fixed operation condition. It was found that both capture efficiency are similar, but the volume of rotating bed is the volume of the conventional packed bed 1/3 times.

碩士
國立成功大學
建築學系
88
Referred to series of the indoor air quality (IAQ) in architecture environment. This study was concentrated on the effect between CO2 and screen porosities on cooking. Find out that relation between CO2 and screen porosities on cooking. Purpose 1.Using the method of experiment, find out the relation on screen porosities、CO2 and ACH on buoyancy effect. 2.Using the method of CFD simulations, find out the relation on screen porosities、CO2 and ACH on buoyancy effect. Method 1.Choose the general model in Taiwan and refer to the conclusion of “a study of ventilation in a residential space－numerical simulation of indoor air environment in kitchen” by Chen Chun－Jung. Then building the laboratory to experimenting. 2.Find out the screen porosities relation to CO2 and ACH on buoyancy effect. Conclusion 1.According to the results of the studying cases with CFD simulation, proving the accuracy of the CFD simulation. 2.From the results of the ACH and porosity, this study introduce a new definition of Effective window area is, Effective window area ＝ window area × screen porosity The regress a predict formula of the kitchen ACH, show follow: ΔACH = 3.8094 xε ΔACH：addition Air Exchange Rate(diffuse heat =540kcal/hr)，h-1 ε：the porosity of high vent 3.From the results of the porosity and CO2 concentration, this study appears the CO2 gather up near the burner. Due to the screen porosity reduce, the CO2 diffuse to other place. The regress a predict formula of CO2 concentration in this study is, CO2 win＝-109.1 ×ε + 908.5 CO2 win： CO2 concentration near the high vent (diffuse heat =540 kcal/hr)，ppm ε：the porosity of high vent

Increasing surface pressure buildup levels and surface venting flow rates on intermediate wellbore casing strings provided an opportunity to analyze wellbore field data to determine a distribution of leakage path permeability values. The gas leakage source in the leaky wellbore originated at depth, and formation gas/fluid traveled along defects in the cement to accumulate at the surface wellhead. The most likely pathway is the cement interface with casing or formation. Due to uncertainty about the location of the leak, and the different methods that were used for calculating leakage parameter values, a range of leakage path permeability values was produced. Most leakage pathway permeability values were greater than intact cement permeability (few microdarcies). This finding supports the practice of using cement filled annuli to provide a safe protective barrier against leakage and to prevent gas flow to surface. Proper cementing techniques are presented in order to identify possible reasons for cracks to form. It is hypothesized that the higher permeability values are a result of cracks in the cement interface with the casing or formation. These types of defects could also be found in wellbores that are in communication with CO2 sequestration reservoirs. The risk of leakage along such existing wellbores associated with CO2 sequestration projects is quantified by the distribution of leakage path permeability. The gas migration path through existing leaky wellbores is an analog for wellbores that are in contact with migrating CO2 plumes. Cracks in the leaky wellbores provide a highly permeable conduit for CO2 to migrate out of the injection zone to the surface. By quantifying leakage path permeability, proper leakage risk assessment can be further developed.
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The natural instability of hydrothermal vents creates variable environmental conditions among habitat patches. Habitat differences correspond to phenotypic variation in Ridgeia piscesae, the only ‘vent tubeworm’ on the spreading ridges of the Northeast Pacific. Ridgeia piscesae that occupy high fluid flux habitats have rapid growth rates and high reproductive output compared to tubeworms in habitats with low rates of venting fluid delivery. As recruitment occurs in all settings, worms in the “optimal habitat” may act as source populations for all habitat types. Ridgeia piscesae is a foundation species in the Endeavour Hydrothermal Vents Marine Protected Area of the Juan de Fuca Ridge. The objective of this thesis was to assess fine scale population structure in Ridgeia piscesae within the Endeavour vent system using genetic data. Population structure was assessed by analysis of the mitochondrial COI gene in 498 individuals collected from three vent sites of the Juan de Fuca Ridge; Middle Valley (n=26), Endeavour Segment (n=444) and Axial Volcano (n=28). Genotyping using microsatellite markers was attempted but all loci developed for closely related tubeworm species failed to amplify microsatellites in Ridgeia piscesae. Sequence analysis identified 32 mitochondrial COI haplotypes; one dominant haplotype (68%), three common haplotypes (4%-7%) and the remainder were rare (<2%). Axial Volcano was differentiated from Middle Valley and Endeavour. Within Endeavour, genetic sub-structuring of Ridgeia piscesae occurred among vent fields (Clam Bed, Main Endeavour and Mothra) and habitat types < 10 km apart. Patterns of genetic variation and coalescent based models suggested that gene flow among vent fields moved in a north to south direction in individuals from high flux habitat but from south to north in individuals from low flux habitat. Tubeworms from low flux habitat had more nucleotide polymorphisms and haplotypes than those from high flux habitats. Estimates of the number of immigrants per generation moving from high flux to low flux subpopulations was four times higher than in the reverse direction. The effective population size was estimated to be three times greater in high flux habitat when the generation times for individuals from each habitat type were considered. Demographic tests for population equilibrium identified a recent and rapidly expanding metapopulation at Endeavour. Models of gene flow in Ridgeia piscesae reflected the general oceanographic circulation described at Endeavour. Genetic data illustrate that dispersing larvae exploit the bi-directional currents created through plume driven circulation within the Endeavour axial valley and suggest that adult position on or near chimneys may influence larval dispersal trajectories upon release. Building on known ecological and biological features, this study also showed that Ridgeia piscesae from limited and ephemeral high flux habitat act as sources to the overall metapopulation and that asymmetrical migration and habitat stability sustain high genetic diversity in low flux sinks. The overall metapopulation at Endeavour experiences frequent extinction and recolonization events, differences in individual reproductive success, and source-sink dynamics that decrease the overall effective size and genetic diversity within the population. These factors have important implications for the conservation of a foundation species.
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lcpuetz@uvic.ca