No description available.

This work reports the convection calibration of Schmidt-Boelter heat flux gages in shear and stagnation air flow. The gages were provided by Sandia National Laboratories and included two one-inch diameter and two one-and-one-half-inch diameter Schmidt-Boelter heat flux gages. In order to calibrate the sensors a convection calibration facility has been designed, including a shear test stand, a stagnation test stand, an air heater and a data acquisition system. The current physical model for a combined radiation and convection heat transfer environment uses an additional thermal resistance around the heat flux gage. This model clearly predicts a non-linear dependency of the gage sensitivity over a range of heat transfer coefficients. A major scope of this work was to experimentally verify the relation found by the model assumptions. Since the actual heat sink temperature is not known and cannot be measured, three different cases have been examined resulting in three different sensitivities for one pressure value, which is the gage sensitivity for the not cooled case and the gage sensitivity for the cooled case, based on the plate temperature or on the cooling water temperature. All of the measured sensitivities for shear as well as for stagnation flow fit well in the theory and show the non-linear decay for increasing heat transfer coefficient values. However, the obtained data shows an offset in the intersection with the sensitivity at zero heat transfer coefficient. This offset might arise from different radiation calibration techniques and different surface coatings of test gage and reference standard. / Master of Science

No description available.

Orientador: Wanda Pereira Almeida / Tese (doutorado) - Universiade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-20T10:19:37Z (GMT). No. of bitstreams: 1 Motta_LuizFrederico_D.pdf: 7487995 bytes, checksum: 147ff46d24e06394d18af036b2472d1e (MD5) Previous issue date: 2012 / Resumo: O objetivo do presente trabalho foi identificar os principais descritores dos derivados análogos de chalcona com intuito de correlacionar com a atividade anti-Candida albicans. A incidência de infecções sistêmicas por C. albicans vem crescendo bastante nos últimos anos, particularmente nos casos de HIV e também em função do aumento da resistência ao arsenal terapêutico existente. Realizamos um estudo QSAR-2D, obtendo um modelo multidimensional pelo método PLS. O modelo obtido possui quatro descritores: refratividade molar, potencial de ionização, comprimento molecular e Verloop B4(A). Com apenas 3 variáveis latentes (PCs), foi capaz de acumular 96,14% da informação original, elucidando 85% da variância total e predizendo 78% da atividade biológica. O modelo proposto possui bom grau de ajuste e significância estatística (R = 0,776 e SEC = 0,229). Os métodos LOO cross-validation, LNO cross-validation, Y-randomization e a validação externa indicaram que o modelo é significante, robusto e possui elevada previsibilidade interna e externa. Levando em consideração o modelo QSAR-2D, propusemos a síntese de novos análogos de chalcona. Realizamos a síntese de 28 chalconas alvo derivadas de aldeídos aromáticos, empregando-se a condensação de Claisen-Schmidt, e avaliamos a atividade anti-Candida albicans. Os compostos foram caracterizados estruturalmente por métodos espectrométricos. Das 28 chalconas alvo, 18 são inéditas. Os rendimentos químicos variaram entre 53% e 98%. Com relação à avaliação da atividade antifúngica, foi realizado o teste de difusão em disco para todos os compostos, empregando o meio RPMI 1640 e seguiram-se os protocolos padrões publicados no documento M27-A2 (CLSI, 2002). As chalconas que apresentaram halo de inibição > 10 mm foram consideradas ativas, e a CIM e CFM foram determinadas pelo método da microdiluição em caldo. O estudo QSAR-2D corroborou o resultado experimental observado. A chalcona mais ativa apresentou CIM = 9 mg/mL, e no teste de citotoxicidade para células 3T3 não mostrou atividade, sugerindo toxicidade seletiva. A chalcona mais ativa apresentou um perfil Drug Likeness e Drug Score baixo em relação ao fluconazol, mas sobreviveu à Regra de Lipinski apresentando biodisponibilidade oral. O MEP, MDEHOMO e MDELUMO da chalcona mais ativa revelou que o orbital HOMO é evidenciado na carbonila, que o carbono C4 possui orbital LUMO e potencial eletrostático positivo, indicando que a chalcona possui centro eletrofílico em C4 sujeito à ocorrência de ataques nucleófilos. O MDEHOMO da glutationa reduzida revelou que o orbital HOMO está no átomo de enxofre do grupo sulfídrila do aminoácido cisteína. Em função da ocorrência do mecanismo de ressonância, as chalconas possuem uma estrutura química com centro eletrofílico no carbono C4, o que indica provável interação entre o orbital HOMO do átomo de enxofre da GSH e o orbital LUMO do carbono C4 da chalcona resultando em ligação covalente e na formação de conjugado glutationa-chalcona. A diminuição na concentração de glutationa reduzida no meio intracelular do fungo resulta em stress oxidativo celular e, portanto morte da Candida albicans / Abstract: The objective of this study is to identify the main descriptors of the derivatives of chalcone analogues with the aim to correlate with the activity anti-Candida albicans. The incidence of systemic infection by C. albicans has increased greatly in recent years, particularly in cases of HIV and also due to increased resistance to existing therapeutic arsenal. We performed a study QSAR-2D, obtained a multidimensional model by PLS method. The obtained model has four descriptors: molar refractivity, ionization potential, molecular length and Verloop B4 (A). With only three latent variables (PCs), was able to earn 96.14% of the original data, explaining 85% of the total variance and predicting 78% of biological activity. The proposed model has a good degree of fit and statistical significance (R = 0.776 and SEC = 0.229). The methods LOO cross-validation, LNO cross-validation, Y-randomization and external validation indicated that the model is significant, robust and has high internal and external predictability. Taking into account the model QSAR-2D, we proposed the synthesis of new analogues of chalcone. We performed the synthesis of 28 chalcones target derived from aromatic aldehydes, using the Claisen-Schmidt condensation, and evaluated the activity anti-Candida albicans. The compounds were characterized by spectrometric methods. Of the 28 chalcones target, 18 are new. The chemical yields ranged between 53% and 98%. Regarding the evaluation of antifungal activity, we performed the disk diffusion test for all compounds, using the RPMI 1640 and followed standard protocols published in document M27-A2 (CLSI, 2002). The chalcones that presented inhibition halo > 10mm were considered active, and the CIM and CFM were determined by broth microdilution. The study QSAR-2D corroborated with the observed experimental result. The most active chalcone showed MIC = 9 mg/mL, and the test of cytotoxicity to 3T3 cells had no activity, suggesting selective toxicity. The chalcone most active gave an overview Drug Likeness and Drug Score low in relation to fluconazole, but survived the Lipinsky Rule of presenting oral bioavailability. The MEP, MDEHOMO and MDELUMO of chalcone most active shown that the HOMO orbital is evidenced in the carbonyl, the carbon C4 has the LUMO orbital and a positive electrostatic potential, indicating that the chalcone has electrophilic center in C4 subject to the occurrence of nucleophilic attack. The MDEHOMO of reduced glutathione revealed that the HOMO orbital on sulfur atom of the sulfhydryl group of the amino acid cysteine. Because the occurrence of the resonance mechanism, the chemical structure of chalcones have a carbon C4 electrophilic, indicating a probable interaction between the HOMO orbital of the sulfur atom of GSH and the LUMO orbital of the carbon C4 of chalcone resulting covalent bond and the formation of glutathione-chalcone conjugated. The decrease in the concentration of reduced glutathione in the intracellular environment of the fungus results in cellular oxidative stress and therefore the death of Candida albicans / Doutorado / Físico-Química / Doutor em Ciências

Les défaut de la vision sont analysés et classés à partir des caractéristiques mathématiques du front d’onde de l’oeil considéré. Après avoir présenté la méthode actuelle basée sur la décomposition du front d’onde dans la base orthonormale de Zernike ainsi que certaines de ses limitations, on propose ici une nouvelle base de décomposition. Celle-ci repose sur l’utilisation del’espace des fronts d’onde polynomiaux de valuation supérieure ou égale à L + 1 (où L est un entier naturel) et permet de décomposer de manière unique un front d’onde polynomial en la somme d’un front d’onde polynomial de bas degré (inférieur ou égal à L) et un front d’onde polynomial de haute valuation (supérieure ou égal à L + 1). En choisissant L = 2, une nouvelle décomposition est obtenue, appelée D2V3, où le front d’onde polynomial de haut degré ne comporte pas de termes de degré radial inférieur ou égal à deux. Cette approche permet de dissocier parfaitement les aberrations optiques corrigibles ou non par le port de lunettes. Différents cas cliniques présentés dans la dernière section permettent de mettre en évidence l’intérêt de cette nouvelle base de décomposition. / The eye vision defaults are analyzed and classified by studyingthe corresponding eye wavefront. After presenting the orthogonal basis, called the Zernike basis, that is currently used for the medical diagnosis, a new decomposition basis is built. It is based on the use of the space of polynomials of valuation greater or equal to L+1 (for L a natural integer). It allows to uniquely decompose a polynomial wavefront into the sum of a polynomial of low degree (lesser or equal to L) and a polynomial of high valuation (greater or equal to L +1). By choosing L = 2, a new decomposition, called D2V3, is obtained where the polynomial wavefront of high degree does not include terms of radial degree lesser or equal to 2. In particular, it allows to quantify perfectly the aberrations that can be corrected by eyeglasses or not. Various clinical examples clearly show the interest of this new basis compared to a diagnosis based on the Zernike decomposition.

Le flot optique est un outil, prometteur et puissant, pour estimer le mouvement des objets de différentes natures, solides ou fluides. Il permet d’extraire les champs de vitesse à partir d’une séquence d’images. Dans cette étude, nous développons la méthode du flot optique pour récupérer, d’une manière précise, le champ de vitesse des mouvements turbulents incompressibles. L’estimation de turbulence consiste à minimiser une fonction d’énergie composée par un terme d’observation et un terme de régularisation. L’équation de transport d’un scalaire passif est alors employée pour représenter le terme d’observation. Cependant, dans le cas où le nombre de Reynolds est grand, et, à cause des contraintes optiques, l’image n’est pas pleinement résolue pour prendre en compte la physique de toutes les échelles de la turbulence. Pour compléter les informations manquantes liées aux physiques des petites échelles, nous adoptons une démarche similaire à celle de Large Eddy Simulation (LES), et, proposons d’utiliser le modèle mixte afin de tenir compte de l’interaction entre les grandes échelles et celles non-résolues. Quant au terme de régularisation, il se repose sur l’équation de continuité des fluides incompressibles. Les tests à l’aide des images synthétiques et expérimentales de la turbulence bi-dimensionnelle - des données des cas test de la communauté du flot optique -, ont non seulement validé notre démarche, mais montrent une amélioration significative des qualités des champs de vitesses extraites. Le cas du flot optique, en 3D, relève encore du défi dans le cas de l’estimation des champs de vitesse de la turbulence. D’une part, contrairement au 2D où il existe des cas tests bien établis, il n’existe pas, à notre connaissance, des séquences d’images 3D référentielles permettant de tester notre démarche et méthode. D’autre part, l’augmentation du coût d’estimation demande des algorithme adaptés. Ainsi, nous sommes amené à utiliser la simulation numérique directe d’écoulement turbulent en présence d’un scalaire passif, pour générer des données de scalaires afin d’évaluer la performance du flot optique. Nous prêtons également attention à l’effet du nombre de Schmidt qui caractérise la relation entre la diffusion moléculaire scalaire et la dissipation de turbulence. Les tests sont ensuite effectués avec cette base de données numériques. Les résultats montrent que la précision de l’estimation augmente avec des nombres de Schmidt plus élevés. Par ailleurs, l’influence du terme de régularisation est aussi étudié au travers deux équations qui se différencient par l’ordre spatial des dérivées partielles. Les résultats numériques montrent que l’équation avec un terme de régularisation de seconde-ordre est meilleure que celle de premier-ordre. / The method of optical flow is a powerful tool for motion estimation. It is able to extract the dense velocity field from image sequence. In this study, we employ this method to retrieve precisely the incompressible turbulent motions. For 2D turbulence estimation, it consists in minimizing an objective function constituted by an observation term and a regularization one. The observation term is based on the transport equation of a passive scalar field. For non-fully resolved scalar images, we propose to use the mixed model in large eddy simulation (LES) to determine the interaction between large-scale motions and the unresolved ones. The regularization term is based on the continuity equation of 2D incompressible flows. Evaluation of the proposed formulation is done over synthetic and experimental images. In addition, we extend optical flow to three dimensional and multiple scalar databases are generated with direct numerical simulation (DNS) in order to evaluate the performance of optical flow in the 3D context. We propose two formulations differing by the order of the regularizer. Numerical results show that the formulation with second-order regularizer outperforms its first-order counterpart. We also draw special attention to the effect of Schmidt number, which characterizes the ratio between the molecular diffusion of the scalar and the dissipation of the turbulence. Results show that the precision of the estimation increases as the Schmidt number increases. Overall, optical flow has showcased its capability of reconstructing the turbulent flow with excellent accuracy. This method has all the potential and attributes to become an effective flow measurement approach in fluid mechanics community.

Differential systems appear modelling many natural phenomena in different branches of sciences, in biological and physical applications among other areas. Differential systems usually have invariant curves and we can obtain a better description of the qualitative behaviour of their solutions using them. Such invariant curves may be algebraic or not and in the case where they are closed, isolated in the set of periodic orbits and without singular points, they are called limit cycles. There is a very famous problem, proposed by David Hilbert in 1900 what ask about the maximum number of limit cycle that all polynomial differential systems of a given degree could present. In this work we investigate the existence of some invariant curves in quadratic polynomial differential systems and in discontinuous piecewise differential systems (they are known as Filippovs systems). Even after hundreds of studies on the phase portraits of real planar quadratic vector fields the complete characterization of their phase portraits is a quite complex task, they depend on twelve parameters, after affine transformations and time rescaling, we have families with five parameters, which is still a large number. So many subclasses have been considered instead of the complete system. In this work we investigate conditions under the parameters of the system for a planar quadratic differential system present invariant algebraic curve of degree 3 (a cubic curve) and a Darboux invariant and obtain all the topological non-equivalent phase portraits of these systems. The increasing interest in the theory of nonsmooth vector fields has been mainly motivated by their strong relation with physics, engineering, biology, economy, and other branches of sciences. In the study of the Filippovs systems, we investigate the number of periodic orbits that they can present. In this study we apply the averaging theory. Such theory is used to study some classical models and we also present generalization of such technique for a class of nonsmooth systems. In addition, we also show how the LyapunovSchmidt reduction method can be used to consider cases where the averaging theory is not sufficient to study periodic solutions. / Sistemas diferenciais aparecem na modelagem de muitos fenômenos naturais em diferentes ramos da ciência, em aplicações biológicas e físicas, entre outras áreas. Sistemas diferenciais geralmente possuem curvas invariantes e podemos obter uma melhor descrição do comportamento qualitativo de suas soluções utilizando-as. Tais curvas invariantes podem ser algébricas ou não e, no caso de serem fechadas, isoladas no conjunto de órbitas periódicas e sem pontos singulares, são chamadas de ciclos limites. Há um problema muito famoso, proposto por David Hilbert em 1900, que questiona o número máximo de ciclos limites que os sistemas diferenciais polinomiais de um determinado grau poderiam apresentar. Neste trabalho investigamos a existência de algumas curvas invariantes em sistemas diferenciais polinomiais quadráticos e em sistemas diferenciais contínuos por partes (eles são conhecidos como sistemas de Filippov). Mesmo após centenas de estudos sobre os retratos de fase dos campos vetoriais reais planares e quadráticos, a caracterização completa de seus retratos de fase é uma tarefa bastante complexa. Eles dependem de doze parâmetros e após transformações afins e reescalonamento de tempo, temos famílias com cinco parâmetros, o que ainda é um grande número. Assim muitas subclasses tem sido consideradas em vez do sistema completo. Neste trabalho investigamos condições sob os parâmetros do sistema para que um sistema diferencial planar quadrático apresente uma curva algébrica invariante de grau 3 (curva cúbica) e um invariante de Darboux e obtemos todos os retratos de fase não equivalentes destes sistemas. O crescente interesse na teoria dos campos de vetores suaves por partes tem sido motivado, principalmente, por sua forte relação com a física, engenharia, biologia, economia e outros ramos das ciências. No estudo dos sistemas de Filippov, investigamos o número de órbitas periódicas que eles podem apresentar. Para este estudo, aplicamos a teoria do averaging. Tal teoria é usada para estudar alguns modelos clássicos e também apresentamos a generalização de tal técnica para uma classe de sistemas suaves por partes. Além disso, mostramos também como o método de redução de Lyapunov Schmidt pode ser usado para considerar casos em que a teoria do averaging sozinha não é suficiente para estudar soluções periódicas.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-01-13T13:09:46Z No. of bitstreams: 2 Dissertação - Laura Vitória Rezende Dias - 2016.pdf: 6797582 bytes, checksum: 102b4a133abc8e93649bbe49a562dcad (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-01-16T11:03:49Z (GMT) No. of bitstreams: 2 Dissertação - Laura Vitória Rezende Dias - 2016.pdf: 6797582 bytes, checksum: 102b4a133abc8e93649bbe49a562dcad (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-01-16T11:03:49Z (GMT). No. of bitstreams: 2 Dissertação - Laura Vitória Rezende Dias - 2016.pdf: 6797582 bytes, checksum: 102b4a133abc8e93649bbe49a562dcad (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-12-05 / This work is the development of a prototype for Stirling engine which was designed with the aim of understanding the machine mainly about the component parts, construction difficulties and type of relevant parameters for its performance. Starting from geometric and thermodynamic data from the prototype, with application of the Schmidt modeling, a digital program was developed to calculate values such as power output and efficiency. The prototype was also used to carryd out bench tests using a data acquisition system implemented in electronics platform Arduino Uno. Using Hall-effect and temperature sensors, following the steps of the algorithm proposed by Conner, it was possible to raise data as temperature and revolutions per minute (rpm) for the flywheel coupled to the prototype shaft, these variables made possible to estimate the power output and operational conditions such as the gas temperature in compression and expansion spaces, etc. The comparison between results from simulations and the bench tests demonstrated the great influence of prototype construction data (volumes, source temperature, etc.) on the output power and the performance of the equipment and also how far is the constructed device from the ideal model proposed by Schmidt. The experiments have shown that the prototype can reach a rotation speed up to 1.200 rpm at 159 degrees Celsius of external engine heat source, with output power of 100 milliwatt. The prototype resulting from this research, although small, has allowed the access to important information that can open paths to the construction of larger Stirling engines and consequently with output powers closer to practical use. / Este trabalho consiste no desenvolvimento de um protótipo didático de motor Stirling, que foi concebido com o intuito de compreender a máquina principalmente em relação as partes componentes, as dificuldades construtivas e os tipos de parâmetros relevantes para o desempenho. Partindo de dados geométricos e termodinâmicos do protótipo, com aplicação da modelagem de Schmidt, elaborou-se um programa digital que permite calcular grandezas como potência de saída e rendimento. Empregando o protótipo, foram também realizados ensaios em bancada de laboratório, para os quais utilizou-se um sistema de aquisição de dados implementado na plataforma eletrônica Arduino Uno. Através do uso de sensores de efeito Hall e de temperatura, seguindo os passos do algoritmo proposto por Conner, foi possível levantar dados como temperatura e revoluções por minuto (rpm) do volante acoplado ao eixo do protótipo, o que permitiu estimar sua potência de saída e as condições operacionais, como a temperatura do gás nos espaços de compressão e expansão, etc. A comparação entre a simulação computacional e os resultados dos ensaios em bancada demonstrou a influência dos dados construtivos do protótipo (volumes, temperatura da fonte, etc.) sobre a potência de saída e o rendimento do protótipo e também o quão distante está o dispositivo construído do modelo ideal proposto por Schmidt. Os resultados obtidos pelos ensaios mostraram que o protótipo alcança velocidade de rotação de até 1.200 rpm a uma temperatura de 159 graus Celsius da fonte térmica externa ao motor, com potência de saída de 100 miliwatt. O protótipo resultante desta pesquisa, apesar de pequeno porte, permitiu a obtenção de informações importantes que podem abrir caminhos para a construção de motores Stirling de maiores dimensões e consequentemente com valores de potências de saída para utilização prática.

Als am 16. Juli 2010 Professor Dr. h.c. Werner Schmidt nach kurzer schwerer Krankheit starb, hatte die Kunstwelt eine der großen Persönlichkeiten der Nachkriegszeit verloren. Fünf Jahrzehnte, zunächst als Direktor des Dresdner Kupferstichkabinetts von 1959 bis 1989, dann als Generaldirektor der Staatlichen Kunstsammlungen Dresden von 1990 bis 1997 und schließlich als Präsident der Sächsischen Akademie der Künste 1996-2001 hat er das Kunstleben Dresdens und des ganzen Landes maßgeblich geprägt.

Diss. : Literaturw. : Bonn : 1990. / Originally presented as the author's thesis (doctoral--Universität Bonn, 1990). Bibliogr. p. 313-329.