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Estudo proteômico do efeito da atmosfera modificada na estabilidade da cor e na vida útil da carne suína acondicionada em embalagens de transporte tipo masterpack sob refrigeração / Proteomics study of the effect of modified atmosphere on colour estability and shelf life of pork meat wrapped in masterpack transport packages under refrigerationRosa, Alessandra Fernandes 13 February 2009 (has links)
Este trabalho teve como objetivo o estudo do efeito da atmosfera modificada associada a embalagens de transporte tipo \"masterpack, na vida útil da carne suína refrigerada. Foram realizadas análises microbiológicas, físico-químicas, bioquímicas e sensoriais visuais. Foram utilizados cortes de lombo suíno (Longissimus dorsi) acondicionados em bandejas de poliestireno expandido recobertas com filme de poli (cloreto de vinila). As bandejas foram acondicionadas em embalagens secundárias de transporte tipo masterpack (6 bandejas por embalagem). Foram utilizados 3 tipos de atmosfera modificada (Composições gasosas): A=75%O2+25%CO2; B= 50%O2+50%CO2 e C=100%CO2. As carnes foram armazenadas em câmara frigorífica por 22 dias. Em intervalos pré-determinados (1, 8, 15 e 22 dias) foram realizadas análises microbiológicas (psicrotróficos aeróbios e Pseudomonas sp.), físico-químicas (composição gasosa, pH, cor, perda de água por exsudação, perda de água por cocção e maciez), bioquímicas (oxidação lipídica, concentração de metamioglobina e eletroforese bi-dimensional) e sensoriais visuais (em balcão expositor). Observou-se que não houve crescimento de microrganismos psicrotróficos aeróbios e Pseudomonas sp. até 15 dias de armazenamento independente da composição gasosa. Houve efeito significativo (P<0,05) de Composição gasosa e de Tempo de armazenamento praticamente em todas as variáveis analisadas, com exceção da perda de água por exsudação, maciez e concentração de metamioglobina. As principais diferenças ocorreram com relação à cor das carnes. De maneira geral, os valores de L* aumentaram durante o armazenamento enquanto que os de a* diminuíram significando que ocorreu certa descoloração da carne. Os bifes das Composições A e B tiveram coloração mais rósea com valores de a* e c* superiores aos da Composição C. As amostras de carne da Composição C tiveram menores valores de TBARS que as demais. A análise sensorial indicou preferência do consumidor pelas amostras das Composições A e B e os resultados de cor determinados após a análise sensorial indicaram que após a abertura dos masterpacks, os bifes sofreram descoloração, sendo que os bifes da Composição A e B mantiveram a coloração rósea por mais tempo. Na análise de eletroforese bi-dimensional realizada com amostras de carne suína da Composição A em 3 tempos distintos, foram identificados média de 255 spots com ponto isoelétrico variando de 3 a 10 e peso molecular de 13 a 94 kDa. Concluiu-se que, do ponto de vista microbiológico, as três composições gasosas estudadas conservaram os bifes de lombo suíno por até 15 dias de armazenamento, porém, somente as atmosferas com altas concentrações de O2 (>50%) garantiram a preservação da cor e aparência geral dos bifes. A técnica da eletroforese bidimensional é promissora para o entendimento, em nível molecular, das mudanças, principalmente de cor, que ocorrem na carne embalada com atmosfera modificada durante o armazenamento. Porém, ainda há a necessidade de mais estudos. / The aim of this work was to study the effect of modified atmosphere associated to \"masterpack\" transport packages in the shelf-life of refrigerated pork meat. Microbiological, physical-chemical, biochemical and visual analyses were made. Pork loin (Longissimus dorsi) cuts placed in trays of expanded polystyrene, covered with poly(vinyl chloride) films were used in this study. The trays were placed in a high gas barrier secondary masterpack (78.5 x 48.5 cm, 0.35m2, Cryovac) package, with six trays per masterpack (MP). Three modified atmosphere (gas compositions) were tested: A=75%O2+25%CO2; B= 50%O2+50%CO2 e C=100%CO2. The meat was kept in a refrigerated chamber for 22 days. At pre-established intervals (1, 8, 15 and 22 days) of storage, microbiological (aerobic psychrotrophic and Pseudomonas sp.), physical-chemical (gaseous composition, pH, colour, dripping loss, cooking loss and tenderness), biochemical (lipid oxidation, metmyoglobin concentration and bidimensional electrophoresis) and visual analyses were carried out. It was observed that for up to 15 days of storage there was neither growth of aerobic psychrotrophic microorganisms nor Pseudomonas sp. independent of the Gas composition. There was significant effect (P<0.05) of Gas composition and of Storage Time in almost all the analyzed variables, except for drip loss, tenderness and metmyoglobin concentration. The main differences found were related to the meat colour. In general, the values of L * increased during storage while a* decreased, meaning some discoloration of meat. The steaks of Gas compositions A and B had better coloration with values of the *a and c * greater than Treatment C. The samples of meat of Gas composition C had lower values for TBARS compared to other treatments. The sensory analysis indicated the panelists´ preference for the samples of Gas compositions A and B, and the colour tests made after the sensorial analysis indicated that the steaks of Treatment A and B maintained the pinky coloration for longer time. In the analysis of bi-dimensional electrophoresis applied to the samples of pork loin meat of Treatment A, carried out in 3 replicates, nearly 255 spots were identified with isoelectric point varying from 3 to 10 and molecular weight from 13 to 94 kDa. Based on the microbiological data, it was concluded that the three studied Gas combinations preserved the pork loin steaks for up to 15 days of storage, however, only the atmospheres with higher concentrations of O2 (>50%) guaranteed the preservation of the colour and the general appearance of the steaks. The bidimensional electrophoresis is a promising technique for the understanding, in molecular level, of the changes, mainly in colour, that happen in modified atmosphere packed meat. However, there is still need for further studies.
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Cognition sociale et Schizophrénie : une approche centrée sur la personne à l’aide du Protocole d’Evaluation de la Cognition Sociale de Bordeaux (PECS-B) / Social cognition and Schizophrenia : a person-centered approach with the Bordeaux Social Cognition Assessment ProtocolEtchepare, Aurore 22 December 2017 (has links)
La cognition sociale a récemment connu un intérêt croissant en neuropsychologique clinique. Cet engouement s’explique notamment par le caractère transdiagnostique mais aussi invalidant des troubles. Cependant, ce construit se heurte encore à de nombreux écueils, tant conceptuels que méthodologiques. Ainsi, dans la schizophrénie, les données de la littérature internationale divergent. Nous faisons l’hypothèse que ces contradictions peuvent être sous-tendues par : 1) le manque de considération pour le caractère multidimensionnel de la cognition sociale, et 2) l’hétérogénéité interindividuelle du fonctionnement. L’objectif général de ce travail de thèse était de réaliser une étude comparée des profils de fonctionnement en cognition sociale dans la population générale et dans la schizophrénie. Pour ce faire, une première étape a été consacrée à une revue systématique des études sur la structure factorielle de la cognition sociale en neuropsychologie clinique (Article 1). Cette revue a permis de proposer un modèle bidimensionnel de la cognition sociale, où les processus de bas et de haut niveau croisent les processus affectifs et cognitifs. Une deuxième étape a consisté à fournir des éléments de validation supplémentaires au PECS-B, une batterie d’évaluation de la cognition sociale composée de sept tâches évaluant cinq dimensions (Article 2). Les résultats ont révélé des qualités psychométriques satisfaisantes en population générale (N = 131) comme dans la schizophrénie (N = 101). Enfin, la troisième étape a consisté à réaliser des analyses en clusters pour explorer l’hétérogénéité interindividuelle dans ces mêmes populations (Article 3). Trois profils différents dans l’échantillon population générale ont été mis en évidence, dont deux caractérisés par des faiblesses spécifiques. En revanche, les trois profils obtenus dans l’échantillon schizophrénie étaient caractérisés par trois niveaux de fonctionnement en cognition sociale : capacités efficientes (similaires aux témoins), moyennes et faibles. Ces deux derniers niveaux étaient également caractérisés par des difficultés d’ordre alexithymique ou neurocognitive. Dans une perspective de pratique basée sur la preuve, ces résultats ont des implications importantes tant pour l’évaluation de la cognition sociale que pour l’orientation des interventions thérapeutiques. / Social cognition has received a growing interest in clinical neuropsychology. This popularity can be explained by the transdiagnostic and negative outcome of social cognition disorders. However, this construct faces many difficulties, conceptual as well as methodological. Thus, concerning schizophrenia, data from the international literature is inconsistent. We hypothesize that these contradictions may be underpinned by: 1) a lack of consideration for the multidimensionality of social cognition, and 2) interindividual heterogeneity of functioning. The overall goal of this thesis was to explore and compare the social cognition functioning profiles in the general population with those for schizophrenia. To do this, a first step was devoted to a systematic review of studies that explored the factor structure of social cognition in clinical neuropsychology (Article 1). This review allowed the proposition of a two-dimensional model of social cognition, in which low and high-level processes cross affective and cognitive ones. A second step was to provide additional validation elements to the PECS-B, a social cognition assessment battery with seven tasks assessing five dimensions (Article 2). The results reported satisfactory psychometric qualities in the general population (N = 131) as well as in schizophrenia (N = 101). Finally, the third step was to carry out cluster analyses to explore interindividual heterogeneity in these same populations (Article 3). Three different profiles in the general population sample were highlighted, of which two were characterized by specific weaknesses. In contrast, the three profiles in the schizophrenia sample were characterized by three levels of social cognition functioning: good (similar to controls), medium and low. The last two levels were also characterized by alexithymic or neurocognitive difficulties. From an evidence-based practice perspective, these findings have important implications for both the assessment and the direction of therapeutic interventions.
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Parental investment across an altitudinal gradient in blue tits (Cyanistes caeruleus)Bruendl, Aisha Colleen January 2017 (has links)
Environmental gradients can help shed light on the evolution of life history strategies such as parental investment. Parental investment is crucial for the fitness of many species. In this thesis, I examine reproductive investment dynamics in the Eurasian blue tit (Cyanistes caeruleus) in the French Pyrenees and assess potential differences in reproductive measures across an altitudinal gradient that creates variation in environmental “harshness”. Further, I investigate fine-scale aspects of bi-parental care, such as investment tactics in current reproduction, and sex differences in contributions to offspring care. To do so, I used a mixture of observational and experimental data, collected over a total of six breeding seasons from over 500 blue tits nests. I showed that breeding conditions are “harsher” due to colder temperatures with increasing elevation, leading to changes in reproductive timing and output. I found that increasing altitude leads to decreased hatching success. Nevertheless, clutch size and brood mortality is comparable across the gradient. A shift to a lower, but qualitatively comparable reproductive output may be part of a slower “pace of life” strategies pursued at high relative to low altitudes. From experimental data, I also found that parental investment is positively linked across different phases within one reproductive attempt. Finally, in line with theory, a temporary brood manipulation revealed that parents balance the benefits and costs of reproduction by partially compensating for changes in brood size. Parents also responded in similar ways to brood size. Overall, the findings presented in this thesis highlight the importance of mechanisms to fine-tune reproduction to maximise reproductive fitness. I suggest that initial reproductive decisions such as timing and amount of offspring produced heavily shape the success of a reproductive attempt. These results have implications for current versus future reproductive trade-offs in life history theory, in particular for short-lived species.
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Aspects of organonitrogen and organosulphur chemistry in synthesis and recognitionRasheed, Omer January 2016 (has links)
Further investigations intending illucidate the mechanism of a newly discovered redox-alkylation reaction of azo dyes are presented. Preliminary results indicate that this reaction most probably proceeds via initial N-alkylation of the anion derived from an alpha-ketohydrazone. An investigation is continued to study the synthesis of macrocycle-carbohydrate-dye hybrids. The development of a modular approach to macrocycle assembly has enabled the synthesis of a library of pyridine-based macrocycles possessing multiple donor sites. A central dye scaffold, prepared from the SNAr reaction between halo-substituted azo dye and a disubstituted phenol, was decorated with a representative carbohydrate or macrocycle using Sharpless click chemistry. Also an "S3N-ligand azo-dye" conjugate has been synthesised with a view to the development of a sensor for heavy metal ions. Complexation of this system with Ag(I), Hg(II) and Cu(II) salts has been investigated. Complexation of the dye to metals results in a bathochromic shift in the absorption maximum of the azo dye, an effect which is most pronounced for Cu(II).The Kobayashi fragmentation has transformed the area of benzyne chemistry as it enables its generation from readily available precursors under mild reaction conditions. The controlled generation of benzyne in this manner has been utilised by many groups, allowing readily access to a variety of functionalised aromatic and heteroaromatic from simple precursors. During the course of a synthetic project, which was to utilise the Kobayashi fragmentation in a key intramolecular Diels-Alder reaction, we noticed that alternate modes of fragmentation/rearrangement accompanied the desired elimination reaction leading to benzyne generation. In particular, competing Fries or Smiles rearrangements became the major routes of fragmentation in appropriately functionalised substrates. The results of an investigation into the factors affecting the course of the Kobayashi fragmentation, together with the development of a novel bi-aryl synthesis are presented in this thesis.
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Computational models for multilingual negation scope detectionFancellu, Federico January 2018 (has links)
Negation is a common property of languages, in that there are few languages, if any, that lack means to revert the truth-value of a statement. A challenge to cross-lingual studies of negation lies in the fact that languages encode and use it in different ways. Although this variation has been extensively researched in linguistics, little has been done in automated language processing. In particular, we lack computational models of processing negation that can be generalized across language. We even lack knowledge of what the development of such models would require. These models however exist and can be built by means of existing cross-lingual resources, even when annotated data for a language other than English is not available. This thesis shows this in the context of detecting string-level negation scope, i.e. the set of tokens in a sentence whose meaning is affected by a negation marker (e.g. 'not'). Our contribution has two parts. First, we investigate the scenario where annotated training data is available. We show that Bi-directional Long Short Term Memory (BiLSTM) networks are state-of-the-art models whose features can be generalized across language. We also show that these models suffer from genre effects and that for most of the corpora we have experimented with, high performance is simply an artifact of the annotation styles, where negation scope is often a span of text delimited by punctuation. Second, we investigate the scenario where annotated data is available in only one language, experimenting with model transfer. To test our approach, we first build NEGPAR, a parallel corpus annotated for negation, where pre-existing annotations on English sentences have been edited and extended to Chinese translations. We then show that transferring a model for negation scope detection across languages is possible by means of structured neural models where negation scope is detected on top of a cross-linguistically consistent representation, Universal Dependencies. On the other hand, we found cross-lingual lexical information only to help very little with performance. Finally, error analysis shows that performance is better when a negation marker is in the same dependency substructure as its scope and that some of the phenomena related to negation scope requiring lexical knowledge are still not captured correctly. In the conclusions, we tie up the contributions of this thesis and we point future work towards representing negation scope across languages at the level of logical form as well.
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Relação entre reflectâncias de imagens orbitais e transporte de sedimentos em suspensão no Rio DoceVilches, Thanira Thammy Bastos 11 March 2013 (has links)
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Previous issue date: 2013-03-11 / Suspended solids transport excess, caused by erosion, may limit water use and cause rivers siltation. Suspended solids concentration may be assessed by remote sensing because the reflectance of the scenes, in the visible and infrared ranges, is positively influenced. This work aims at the understanding of the variability of suspended sediments concentrations in a Doce river stretch located in Espírito Santo state, Brazil, through spectral analysis of satellite images data and analysis of field measurements results. There were analyzed suspended solids concentrations for samples collected in Regência and Colatina Doce river sections and images captured by LANDSAT 5 TM satellite. To obtain reflectance values, the following operations were performed: geometric correction, conversion of DN values to apparent FRB values, atmospheric correction, using the 6S model (FRB surface), and transformation of NCs values.The results showed that, for the images corrected from atmospheric effects, the values of the ND curve related to the apparent FRB are higher than the values of the surface s FRB curve in the visible region, due to the electromagnetic radiation scattering phenomenon. In the near-infrared regions, the reverse was observed, because of the absorption of electromagnetic radiation by the atmosphere. It was observed positive correlation between reflectance and suspended solids concentration, despite the difficulties in obtaining data from same satellite images and field sample collection dates. For Regência data, the best correlation was obtained for band 1, located in the visible range of the surface s FRB curve, suggesting less suspended sediment transport. For Colatina, the best correlation occurred for band 4, located in the near-infrared range of the same surface s FRB curve, indicating greater sediment transport in this part of the Doce river during the sampling dates. It was concluded that the surface reflectance best represents the water spectral curve and that the correlated data showed the following pattern: smaller reflectance corresponds to lower water suspended solids concentration / O transporte de sólidos em suspensão, causado por erosão, é um dos problemas que limitam o uso da água, podendo causar assoreamento nos rios. A concentração de sólidos suspensos pode ser avaliada através do sensoriamento remoto, pois a
reflectância da cena, na faixa do visível e do infravermelho, é positivamente influenciada. Desta forma, este trabalho visa o conhecimento da variabilidade das concentrações de sedimentos em suspensão no trecho do rio Doce localizada no
ES, através de análises de dados espectrais contidos nas imagens orbitais e de resultados de medições em campo. Para tanto, foram avaliados dados concentrações de sólidos suspensos em amostras coletadas em Regência e Colatina, e imagens TM do satélite LANDSAT 5. Para obtenção dos valores de reflectância, foram realizadas as seguintes operações: correção geométrica, conversão dos NDs para valores de FRB aparente, correção atmosférica com uso do modelo 6S (FRB superfície), e transformação de NCs em valores de reflectância. Os resultados mostraram que nas imagens corrigidas dos efeitos atmosféricos, os valores da curva de ND referentes aos FRBs aparentes são superiores aos valores
da curva FRB de superfície na região do visível, devido ao fenômeno de espalhamento da radiação eletromagnética. Nas regiões do infravermelho próximo, ocorreu o inverso, uma vez que há absorção da radiação eletromagnética pela
atmosfera. Quanto aos sólidos suspensos, foram encontradas correlações positivas entre a reflectância e a concentração dos sólidos suspensos, apesar das dificuldades de obtenção de dados concomitantes das datas de imagens orbitais
com datas da coleta de campo. Para os dados de Regência, a melhor correlação ocorreu para banda 1, que se localiza na faixa do visível, da curva dos FRB de superfície, sugerindo menor transporte de sedimentos suspensos. Para Colatina,
ocorreu para banda 4, que se encontra na faixa do infravermelho próximo, também para curva dos FRB de superfície, sugerindo maior transporte de sedimentos nesse
trecho do rio Doce, para as datas de amostragem. Conclui-se que a reflectância que melhor representa a curva espectral da água é de superfície e os dados correlacionados seguiram o padrão de quanto menores as reflectâncias, menores as
concentrações de sólidos suspensos na água
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Numerical and Experimental Studies of Deployment Dynamics of Space Webs and CubeSat BoomsMao, Huina January 2017 (has links)
In this thesis, experiments and simulations are performed to study the deployment dynamics of space webs and space booms, focusing on the deployment and stabilization phases of the space web and the behavior of the bi-stable tape spring booms after long-term stowage. The space web, Suaineadh, was launched onboard the sounding rocket REXUS-12 from the Swedish launch base Esrange in Kiruna on 19 March 2012. It served as a technology demonstrator for a space web. A reaction wheel was used to actively control the deployment and stabilization states of the 2×2 m2 space web. After ejection from the rocket, the web was deployed but entanglements occurred since the web did not start to deploy at the specified angular velocity. The deployment dynamics was reconstructed by simulations from the information recorded by inertial measurement units and cameras. Simulations show that if the web would have started to deploy at the specified angular velocity, the web would most likely have been deployed and stabilized in space by the motor, reaction wheel and controller used in the experiment. A modified control method was developed to stabilize the out-of-plane motions before or during deployment. New web arms with tape springs were proposed to avoid entanglements. A deployable booms assembly composed of four 1-m long bi-stable glass fiber tape springs was designed for the electromagnetically clean 3U CubeSat Small Explorer for Advanced Missions (SEAM). The deployment dynamics and reliability of the SEAM boom design after long-term stowage were tested by on-ground experiments. A simple analytical model was developed to predict the deployment dynamics and to assess the effects of the GOLS and the combined effects of friction, viscoelastic strain energy relaxation, and other factors that act to decrease the deployment force. In order to mitigate the viscoelastic effects and thus ensure self-deployment, different tape springs were designed, manufactured and tested. A numerical model was used to assess the long-term stowage effects on the deployment capability of bi-stable tape springs including the friction, nonlinear-elastic and viscoelastic effects. A finite element method was used to model a meter-class fully coiled bi-stable tape spring boom and verified by analytical models. / <p>QC 20170508</p> / SEAM
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Srovnání BI platforem IBM Cognos a SAP BO / Comparison of BI platforms IBM Cognos and SAP BONovák, Ondřej January 2011 (has links)
Business Intelligence platforms contain many detailed tools with overlapping functionality. The primary aim of this thesis is to compare two BI platforms from leaders in the market - IBM Cognos BI (version 10) and SAP Business Objects (version 3.1). This comparison emphasises their practical usefulness in both ad hoc and standard reporting. In the first theoretical chapter there is a definition of basic terms and a brief description of the BI solution. In the following two chapters there are detailed descriptions of IBM Cognos BI and SAP Business Objects platforms including the most important tools. The theoretical part of this thesis is based mostly on documentation. The practical part of this thesis defines criteria for the evaluation of BI platforms. Following this chapter is the main comparison based mostly on my practical experience with each tool and experience from a migration project from IBM Cognos to SAP BO. Workarounds are described in some cases to compensate for missing functionality. The results this thesis are evaluation criteria as well as a description and comparison of both platforms. The merit of this thesis is an identification of problematic functionality present in BI solutions from the points of view of new development, implementation and migration.
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Proteção contra a corrosão das ligas de alumínio AA7075-T6 e AA8006-F utilizando bicamadas do tipo polianilina e camadas de cerato / Corrosion protection of AA7075-T6 and AA8006-F aluminum alloys using bi-layers based on polyaniline and cerium conversion layersLeandro Duarte Bisanha 23 January 2014 (has links)
O desenvolvimento de novos revestimentos ou métodos de proteção considerados ambientalmente amigáveis é extremamente importante para a substituição das eficientes camadas de conversão do cromo, as quais são amplamente utilizadas para proteção anticorrosiva do alumínio e suas ligas. Entre as alternativas relatadas na literatura, podemos destacar a aplicação de filmes de polianilina (PAni) e o uso de camadas de conversão de cério. Neste trabalho é proposta a utilização de revestimentos do tipo bicamadas formada pela combinação de: 1) duas camadas de polianilina ou 2) camadas de conversão de cério (depositadas pelo método electroless ou catodicamente) e filmes de PAni para proteção contra a corrosão das ligas de alumínio AA7075-T6 e AA8006-F em meio aquoso contendo íons cloreto. Nos ensaios de corrosão foram utilizados o monitoramento do potencial de circuito aberto e a polarização potenciodinâmica em meio de NaCl 0,6 mol L-1. A superfície das ligas com e sem os recobrimentos foram analisadas por microscopia óptica e microscopia eletrônica de varredura. Também foi realizado o teste de aderência dos filmes de PAni presentes nas bicamadas sobre as ligas estudadas. O revestimento bicamada composto por uma camada de filme de PAni quimicamente depositada e um filme casting de PAni apresenta excelente aderência sobre as ligas AA7075-T6 e AA8006-F e combina a proteção oferecida pelos filmes casting com a boa aderência dos filmes de PAni depositados quimicamente. O uso da bicamada de cerato electroless e PAni apresenta propriedades anticorrosivas inferiores quando comparadas ao filme de PAni aplicado diretamente sobre o substrato metálico, entretanto, o uso de cerato electroless melhora a aderência dos filmes casting de PAni sobre as ligas estudas. O uso de bicamadas formadas por cerato depositado catodicamente e PAni sobre a liga AA8006-F apresenta valores de potencial de corrosão e potencial de pite inferiores ao do filme casting de PAni aplicado diretamente sobre o substrato metálico, enquanto que para a liga AA7075-T6 foram obtidas melhores propriedades anticorrosivas quando utilizada uma camada de cerato espessa (obtida utilizando uma solução de cério contendo 8 ou 25 µL mL-1 de H2O2). / The development of new coatings or protection methods considered environmentally friendly is extremely important to replace the efficient conversion layers of chromium, which are widely used for corrosion protection of aluminum and its alloys. Among the alternative methods reported in the literature, it can be highlighted the application of polyaniline (PAni) films and the use of cerium conversion layers. This work proposes the use of bi-layers based on: 1) two layers of polyanilines or 2) combination cerium conversion layers (deposited by electroless or cathodic electrodeposition) and PAni films for corrosion protection of AA7075-T6 and AA8006-F alloys in aqueous solutions containing chloride ions. Open circuit potential and potentiodynamic polarization curves were used for the corrosion tests, which were performed in 0.6 mol L-1 NaCl solution. The surface of the alloys with and without the coatings were characterized by optical microscopy and scanning electronic microscopy. It was also performed the adhesion test of the PAni films present in the bi-layers on the studied alloys. The bi-layers formed by a layer of PAni chemically deposited and a layer of PAni film exhibited excellent adhesion to the AA7075-T6 and AA8006-F alloys and combined the protection offered by the cast film of PAni with the good adhesion of PAni chemically deposited. The use of a bi-layer formed by cerium oxides (deposited by electroless) with PAni film as coating presented lower anticorrosive properties compared to the PAni films applied directly on the substrate, however, the use of the cerium layer improves the adhesion of the PAni films on the alloys. The use of bi-layers formed by electrodeposited cerium oxides and PAni films on AA8006-F showed corrosion potential and pitting potential lower when compared with the PAni film directly applied on the substrate, whereas for AA7075-T6, the best anticorrosive properties was obtained using a thick cerium layer (cerium solution containing 8 or 25 µL mL-1 of H2O2).
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Integration of electric vehicles in a flexible electricity demand side management frameworkWu, Rentao January 2018 (has links)
Recent years have seen a growing tendency that a large number of generators are connected to the electricity distribution networks, including renewables such as solar photovoltaics, wind turbines and biomass-fired power plants. Meanwhile, on the demand side, there are also some new types of electric loads being connected at increasing rates, with the most important of them being the electric vehicles (EVs). Uncertainties both from generation and consumption of electricity mentioned above are thereby being introduced, making the management of the system more challenging. With the proportion of electric vehicle ownership rapidly increasing, uncontrolled charging of large populations may bring about power system issues such as increased peak demand and voltage variations, while at the same time the cost of electricity generation, as well as the resulting Greenhouse Gases (GHG) emissions, will also rise. The work reported in this PhD Thesis aims to provide solutions to the three significant challenges related to EV integration, namely voltage regulation, generation cost minimisation and GHG emissions reduction. A novel, high-resolution, bottom-up probabilistic EV charging demand model was developed, that uses data from the UK Time Use Survey and the National Travel Survey to synthesise realistic EV charging time series based on user activity patterns. Coupled with manufacturers' data for representative EV models, the developed probabilistic model converts single user activity profiles into electrical demand, which can then be aggregated to simulate larger numbers at a neighbourhood, city or regional level. The EV charging demand model has been integrated into a domestic electrical demand model previously developed by researchers in our group at the University of Edinburgh. The integrated model is used to show how demand management can be used to assist voltage regulation in the distribution system. The node voltage sensitivity method is used to optimise the planning of EV charging based on the influence that every EV charger has on the network depending on their point of connection. The model and the charging strategy were tested on a realistic "highly urban" low voltage network and the results obtained show that voltage fluctuation due to the high percentage of EV ownership (and charging) can be significantly and maintained within the statutory range during a full 24-hour cycle of operation. The developed model is also used to assess the generation cost as well as the environmental impact, in terms of GHG emissions, as a result of EV charging, and an optimisation algorithm has been developed that in combination with domestic demand management, minimises the incurred costs and GHG emissions. The obtained results indicate that although the increased population of EVs in distribution networks will stress the system and have adverse economic and environmental effects, these may be minimised with careful off-line planning.
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