Influence of structural nonlinearities in stall-induced aeroelastic response of pitching airfoils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise da influência de variantes do método de solução de escoamentos utilizando os métodos de elementos finitos com compressibilidade artificial e pseudo-características

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação comparativa do grau de deformação plástica aplicado a componentes obtidos por conformação

The manufacturing process of components of Pressure Vessels has a great importance in the efficiency during the operation and life cycle of the equipment. Taking this into account, the objective of this dissertation was to analyze the methods to determine the strain rate in formed components by measuring the components themselves, and posterior results comparison with the values found in manufacturing standards of Pressure vessels. In this study the whole manufacturing process of a component from a pressure vessel, known as Head or End, was accompanied. Using the methodology obtained from literatures it was possible to execute the relative and logarithmic deformation measurements of these components and compare with the obtained results by means of equations presented in the Standards as AD-Merkblatt and ASME (for pressure vessels). The found results were also compared with the logarithmic methodology, taking into account the deformation of the empirical mesh and the thickness of the components studied. It is possible to conclude from this study that despite the existence of empirical methods of measurement of strain rate in components plastically formed, it is recommended the adoption in all situation of the component manufacturing standard. It can be noticed and explained during the development of this study and through the results found

Determinação comparativa do grau de deformação plástica aplicado a componentes obtidos por conformação

The manufacturing process of components of Pressure Vessels has a great importance in the efficiency during the operation and life cycle of the equipment. Taking this into account, the objective of this dissertation was to analyze the methods to determine the strain rate in formed components by measuring the components themselves, and posterior results comparison with the values found in manufacturing standards of Pressure vessels. In this study the whole manufacturing process of a component from a pressure vessel, known as Head or End, was accompanied. Using the methodology obtained from literatures it was possible to execute the relative and logarithmic deformation measurements of these components and compare with the obtained results by means of equations presented in the Standards as AD-Merkblatt and ASME (for pressure vessels). The found results were also compared with the logarithmic methodology, taking into account the deformation of the empirical mesh and the thickness of the components studied. It is possible to conclude from this study that despite the existence of empirical methods of measurement of strain rate in components plastically formed, it is recommended the adoption in all situation of the component manufacturing standard. It can be noticed and explained during the development of this study and through the results found

Synthesis of a functionalized europium complex and deposition of luminescent Langmuir-Blodgett (LB) films

The synthesis, characterization and formation of Langmuir-Blodgett (LB)films for the luminescent [(C12H25)(2)(CH3)(2)N][Eu(tta)(4)] complex, where [(C12H25)(2)(CH3)(2)](N+) is didodecyldimethylammonium and the tta ligand is thenoyltrifluoroacetone, are reported. The coordination of tta ligands to the Eu3+ ion was confirmed by FTIR spectroscopy and the emission spectrum comprised bands corresponding to D-5(0) -> F-7(0-4) transitions. The lifetime (tau) from the emission state (D-5(0))was 0.41 ms, measured by monitoring the hypersensitive D-5(0) -> F-7(2) transition, with the curve being fitted with a first-order exponential function. The surface pressure-area isotherm indicated that the anionic complex may form condensed structures at the air-water interface due to the amphiphilic properties of the counter ion and the beta-diketone ligand. Y-type LB films of [(C12H25)(2)(CH3)(2)N][Eu(tta)(4)] were deposited on quartz substrates, with preserved luminescence and a band assigned to the D-5(0) -> F-7(2) transition. The molecular arrangement at the air/water interface and the preserved luminescence in LB films are consistent with theoretical predictions using a semi-empirical Sparkle/AM1 calculation method for the molecule in vacuum. These tools were used for the first time to predict the behavior of organized films.

Desempenho de métodos de estimativa da evapotranspiração de referência nas localidades de Frederico Westphalen e Palmeira das Missões, RS

A estimativa da evapotranspiração de referência (ETo), usada no balanço hídrico, possibilita quantificar o armazenamento de água no solo, auxiliando no manejo da irrigação. O objetivo do trabalho foi comparar métodos mais simples de estimativa da evapotranspiração de referência com o método Penman-Monteith (FAO), nas escalas diária e de 5, 10, 15 e 30 dias, e mensal, para os municípios de Frederico Westphalen e Palmeira das Missões, no RS. Os métodos avaliados tenderam a melhorar a eficiência com o aumento da escala temporal de estudo, mantendo o mesmo desempenho para ambas as localidades. Os maiores e menores valores de ETo ocorreram nos meses de dezembro e junho, respectivamente. A maioria dos métodos subestimou os valores de ETo. Em qualquer escala temporal, os métodos de Makking e da Radiação FAO24 podem substituir o modelo de Penman-Monteith.

Simulação tridimensional adaptativa da separação das fases de uma mistura bifásica usando a equação de Cahn-Hilliard

Simulamos a separação dos componentes de uma mistura bifásica com a equação de Cahn-Hilliard. Esta equação contém intrincados termos não lineares e derivadas de alta ordem. Além disso, a delgada região de transição entre os componentes da mistura requer muita resolução. Assim, determinar a solução numérica da equação de Cahn-Hilliard não é uma tarefa fácil, principalmente em três dimensões. Conseguimos a resolução exigida no tempo usando uma discretização semi-implícita de segunda ordem. No espaço, obtemos a precisão requerida utilizando malhas refinadas localmente com a estratégia AMR. Essas malhas se adaptam dinamicamente para recobrir a região de transição. O sistema linear proveniente da discretização é solucionado por intermédio de técnicas multinível-multigrid.

Democracy Reconsidered : Britain, France, Sweden, and the EU

The purpose of this thesis is to investigate whether some positions in democratic theory should be adjusted or abandoned in view of internationalisation; and if adjusted, how. More specifically it pursues three different aims: to evaluate various attempts to explain levels of democracy as consequences of internationalisation; to investigate whether the taking into account of internationalisation reveals any reason to reconsider what democracy is or means; and to suggest normative interpretations that cohere with the adjustments of conceptual and explanatory democratic theory made in the course of meeting the other two aims. When empirical methods are used, the scope of the study is restricted to West European parliamentary democracies and their international affairs. More particularly, the focus is on the making of budget policy in Britain, France, and Sweden after the Second World War, and recent budget policy in the European Union. The aspects of democracy empirically analysed are political autonomy, participation, and deliberation. The material considered includes parliamentary debates, official statistics, economic forecasts, elections manifestos, shadow budgets, general election turnouts, regulations of budget decision-making, and staff numbers in government and parliament budgetary divisions. The study reaches the following conclusions among others. (i) The fact that internationalisation increases the divergence between those who make and those who are affected by decisions is not by itself a democratic problem that calls for political reform. (ii) That international organisations may have authorities delegated to them from democratic states is not sufficient to justify them democratically. Democratisation still needs to be undertaken. (iii) The fear that internationalisation dissolves a social trust necessary for political deliberation within nations seems to be unwarranted. If anything, views argued by others in domestic budgetary debate are taken increasingly serious during internationalisation. (iv) The major difficulty with deliberation seems to be its inability to transcend national boundaries. International deliberation at state level has not evolved in response to internationalisation and it is undeveloped in international institutions. (v) Democratic political autonomy diminishes during internationalisation with regard to income redistribution and policy areas taken over by international organisations, but it seems to increase in public spending. (vi) In the area of budget policy-making there are no signs that governments gain power at the expense of parliaments during internationalisation. (vii) To identify crucial democratic issues in a time of internationalisation and to make room for theoretical virtues like general applicability and normative fruitfulness, democracy may be defined as a kind of politics where as many as possible decide as much as possible.

Studio dei metodi di valutazione della pericolosità associata ai "debris flow" in ambiente alpino

The present work concerns with the study of debris flows and, in particular, with the related hazard in the Alpine Environment. During the last years several methodologies have been developed to evaluate hazard associated to such a complex phenomenon, whose velocity, impacting force and inappropriate temporal prediction are responsible of the related high hazard level. This research focuses its attention on the depositional phase of debris flows through the application of a numerical model (DFlowz), and on hazard evaluation related to watersheds morphometric, morphological and geological characterization. The main aims are to test the validity of DFlowz simulations and assess sources of errors in order to understand how the empirical uncertainties influence the predictions; on the other side the research concerns with the possibility of performing hazard analysis starting from the identification of susceptible debris flow catchments and definition of their activity level. 25 well documented debris flow events have been back analyzed with the model DFlowz (Berti and Simoni, 2007): derived form the implementation of the empirical relations between event volume and planimetric and cross section inundated areas, the code allows to delineate areas affected by an event by taking into account information about volume, preferential flow path and digital elevation model (DEM) of fan area. The analysis uses an objective methodology for evaluating the accuracy of the prediction and involve the calibration of the model based on factors describing the uncertainty associated to the semi empirical relationships. The general assumptions on which the model is based have been verified although the predictive capabilities are influenced by the uncertainties of the empirical scaling relationships, which have to be necessarily taken into account and depend mostly on errors concerning deposited volume estimation. In addition, in order to test prediction capabilities of physical-based models, some events have been simulated through the use of RAMMS (RApid Mass MovementS). The model, which has been developed by the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) in Birmensdorf and the Swiss Federal Institute for Snow and Avalanche Research (SLF) takes into account a one-phase approach based on Voellmy rheology (Voellmy, 1955; Salm et al., 1990). The input file combines the total volume of the debris flow located in a release area with a mean depth. The model predicts the affected area, the maximum depth and the flow velocity in each cell of the input DTM. Relatively to hazard analysis related to watersheds characterization, the database collected by the Alto Adige Province represents an opportunity to examine debris-flow sediment dynamics at the regional scale and analyze lithologic controls. With the aim of advancing current understandings about debris flow, this study focuses on 82 events in order to characterize the topographic conditions associated with their initiation , transportation and deposition, seasonal patterns of occurrence and examine the role played by bedrock geology on sediment transfer.

Bestimmung mechanischer Eigenschaften dünner Polymerfilme mittels AFM-Kraft-Abstands-Kurven

In der vorliegenden Arbeit wurden AFM-Kraft-Abstands-Kurven benutzt, um die mechanischen Eigenschaften dünner Polymerfilme verschiedener Schichtdicken (2 - 400 nm) auf einem sehr viel steiferen Substrat (mechanische Doppelschichten) zu untersuchen. Die mechanischen Eigenschaften einer solchen Probe setzen sich aus den mechanischen Eigenschaften der Bestandteile, d.h. Polymer und Substrat, zusammen. Der Beitrag der Bestandteile hängt von der Schichtdicke und von der Auflagekraft ab. Es wurden existierende Modelle für die Auswertung von an Doppelschichten gemessenen Deformationskurven überprüft und festgestellt, dass kein Modell befriedigende Ergebnisse erzielt. Dies zeigte die Notwendigkeit einer neuen semiempirischen Theorie zur Beschreibung der Deformationskurven von mechanischen Doppelschichten. In dieser Arbeit wird der hyperbolische Fit zu diesem Zweck eingeführt. Die Validität des hyperbolischen Fit wurde anhand von drei Experimenten gezeigt. Alle experimentellen Kurven konnten sehr gut durch den hyperbolischen Fit beschrieben werden. Die Elastizitätsmoduln der Bestandteile konnten in Übereinstimmung mit den Literaturwerten berechnet werden. Die Schichtdicken der Proben konnten in allen Fällen mit großer Exaktheit bestimmt werden. Es wurde zudem die Möglichkeit der Auswertung einzelner Kraft-Abstands-Kurven untersucht. Damit konnte die Schichtdicke der untersuchten Doppelschichten ortsaufgelöst im Submikrometerbereich bestimmt werden und ein verstecktes Substrat detektiert werden. Die Adhäsion an der Grenzfläche Polymer/Substrat hat einen fundamentalen Einfluss auf die mechanischen Eigenschaften der Doppelschicht, der qualitativ im letzten Teil der Doktorarbeit gezeigt werden konnte.

Investigation of the dipole response of nickel isotopes in the presence of a high-frequency electromagnetic field

The electric dipole response of neutron-rich nickel isotopes has been investigated using the LAND setup at GSI in Darmstadt (Germany). Relativistic secondary beams of 56−57Ni and 67−72Ni at approximately 500 AMeV have been generated using projectile fragmentation of stable ions on a 4 g/cm2 Be target and subsequent separation in the magnetic dipole fields of the FRagment Separator (FRS). After reaching the LAND setup in Cave C, the radioactive ions were excited electromagnetically in the electric field of a Pb target. The decay products have been measured in inverse kinematics using various detectors. Neutron-rich 67−69Ni isotopes decay by the emission of neutrons, which are detected in the LAND detector. The present analysis concentrates on the (gamma,n) and (gamma,2n) channels in these nuclei, since the proton and three-neutron thresholds are unlikely to be reached considering the virtual photon spectrum for nickel ions at 500 AMeV. A measurement of the stable 58Ni isotope is used as a benchmark to check the accuracy of the present results with previously published data. The measured (gamma,n) and (gamma,np) channels are compared with an inclusive photoneutron measurement by Fultz and coworkers, which are consistent within the respective errors. The measured excitation energy distributions of 67−69Ni contain a large portion of the Giant Dipole Resonance (GDR) strength predicted by the Thomas-Reiche-Kuhn energy-weighted sum rule, as well as a significant amount of low-lying E1 strength, that cannot be attributed to the GDR alone. The GDR distribution parameters are calculated using well-established semi-empirical systematic models, providing the peak energies and widths. The GDR strength is extracted from the chi-square minimization of the model GDR to the measured data of the (gamma,2n) channel, thereby excluding any influence of eventual low-lying strength. The subtraction of the obtained GDR distribution from the total measured E1 strength provides the low-lying E1 strength distribution, which is attributed to the Pygmy Dipole Resonance (PDR). The extraction of the peak energy, width and strength is performed using a Gaussian function. The minimization of trial Gaussian distributions to the data does not converge towards a sharp minimum. Therefore, the results are presented by a chi-square distribution as a function of all three Gaussian parameters. Various predictions of PDR distributions exist, as well as a recent measurement of the 68Ni pygmy dipole-resonance obtained by virtual photon scattering, to which the present pygmy dipole-resonance distribution is also compared.

Modellazione Tridimensionale del Processo di Combustione di un Razzo a Propellente Solido

La regolazione dei sistemi di propulsione a razzo a propellente solido (Solid Rocket Motors) ha da sempre rappresentato una delle principali problematiche legate a questa tipologia di motori. L’assenza di un qualsiasi genere di controllo diretto del processo di combustione del grano solido, fa si che la previsione della balistica interna rappresenti da sempre il principale strumento utilizzato sia per definire in fase di progetto la configurazione ottimale del motore, sia per analizzare le eventuali anomalie riscontrate in ambito sperimentale. Variazioni locali nella struttura del propellente, difettosità interne o eterogeneità nelle condizioni di camera posso dare origine ad alterazioni del rateo locale di combustione del propellente e conseguentemente a profili di pressione e di spinta sperimentali differenti da quelli previsti per via teorica. Molti dei codici attualmente in uso offrono un approccio piuttosto semplificato al problema, facendo per lo più ricorso a fattori correttivi (fattori HUMP) semi-empirici, senza tuttavia andare a ricostruire in maniera più realistica le eterogeneità di prestazione del propellente. Questo lavoro di tesi vuole dunque proporre un nuovo approccio alla previsione numerica delle prestazioni dei sistemi a propellente solido, attraverso la realizzazione di un nuovo codice di simulazione, denominato ROBOOST (ROcket BOOst Simulation Tool). Richiamando concetti e techiche proprie della Computer Grafica, questo nuovo codice è in grado di ricostruire in processo di regressione superficiale del grano in maniera puntuale, attraverso l’utilizzo di una mesh triangolare mobile. Variazioni locali del rateo di combustione posso quindi essere facilmente riprodotte ed il calcolo della balistica interna avviene mediante l’accoppiamento di un modello 0D non-stazionario e di uno 1D quasi-stazionario. L’attività è stata svolta in collaborazione con l’azienda Avio Space Division e il nuovo codice è stato implementato con successo sul motore Zefiro 9.

Development of an X-ray spectrometric system and feasibility tests of Silicon Drift Detector for medical and space applications

The thesis work concerns X-ray spectrometry for both medical and space applications and is divided into two sections. The first section addresses an X-ray spectrometric system designed to study radiological beams and is devoted to the optimization of diagnostic procedures in medicine. A parametric semi-empirical model capable of efficiently reconstructing diagnostic X-ray spectra in 'middle power' computers was developed and tested. In addition, different silicon diode detectors were tested as real-time detectors in order to provide a real-time evaluation of the spectrum during diagnostic procedures. This project contributes to the field by presenting an improved simulation of a realistic X-ray beam emerging from a common X-ray tube with a complete and detailed spectrum that lends itself to further studies of added filtration, thus providing an optimized beam for different diagnostic applications in medicine. The second section describes the preliminary tests that have been carried out on the first version of an Application Specific Integrated Circuit (ASIC), integrated with large area position-sensitive Silicon Drift Detector (SDD) to be used on board future space missions. This technology has been developed for the ESA project: LOFT (Large Observatory for X-ray Timing), a new medium-class space mission that the European Space Agency has been assessing since February of 2011. The LOFT project was proposed as part of the Cosmic Vision Program (2015-2025).

High sensitivity analysis of BRAF mutations in neoplastic and non-neoplastic thyroid lesions

The clonal distribution of BRAFV600E in papillary thyroid carcinoma (PTC) has been recently debated. No information is currently available about precursor lesions of PTCs. My first aim was to establish whether the BRAFV600E mutation occurs as a subclonal event in PTCs. My second aim was to screen BRAF mutations in histologically benign tissue of cases with BRAFV600E or BRAFwt PTCs in order to identify putative precursor lesions of PTCs. Highly sensitive semi-quantitative methods were used: Allele Specific LNA quantitative PCR (ASLNAqPCR) and 454 Next-Generation Sequencing (NGS). For the first aim 155 consecutive formalin-fixed and paraffin-embedded (FFPE) specimens of PTCs were analyzed. The percentage of mutated cells obtained was normalized to the estimated number of neoplastic cells. Three groups of tumors were identified: a first had a percentage of BRAF mutated neoplastic cells > 80%; a second group showed a number of BRAF mutated neoplastic cells < 30%; a third group had a distribution of BRAFV600E between 30-80%. The large presence of BRAFV600E mutated neoplastic cell sub-populations suggests that BRAFV600E may be acquired early during tumorigenesis: therefore, BRAFV600E can be heterogeneously distributed in PTC. For the second aim, two groups were studied: one consisted of 20 cases with BRAFV600E mutated PTC, the other of 9 BRAFwt PTCs. Seventy-five and 23 histologically benign FFPE thyroid specimens were analyzed from the BRAFV600E mutated and BRAFwt PTC groups, respectively. The screening of BRAF mutations identified BRAFV600E in “atypical” cell foci from both groups of patients. “Unusual” BRAF substitutions were observed in histologically benign thyroid associated with BRAFV600E PTCs. These mutations were very uncommon in the group with BRAFwt PTCs and in BRAFV600E PTCs. Therefore, lesions carrying BRAF mutations may represent “abortive” attempts at cancer development: only BRAFV600E boosts neoplastic transformation to PTC. BRAFV600E mutated “atypical foci” may represent precursor lesions of BRAFV600E mutated PTCs.

E-ToF-Messungen mit kalorimetrischen Tieftemperatur-Detektoren zur Bestimmung spezischer Energieverluste und zur Massenidentifikation niederenergetischer Schwerionen

Kalorimetrische Tieftemperatur-Detektoren (Calorimetric Low Temperature Detectors, CLTDs) wurden erstmals in Messungen zur Bestimmung des spezifischen Energieverlustes (dE/dx) niederenergetischer Schwerionen beim Durchgang durch Materie eingesetzt. Die Messungen wurden im Energiebereich unterhalb des Bragg-Peaks, mit 0.1 - 1.4 MeV/u 238U-Ionen in Kohlenstoff und Gold sowie mit 0.05 - 1.0 MeV/u 131Xe-Ionen in Kohlenstoff, Nickel und Gold, durchgeführt. Die Kombination der CLTDs mit einem Flugzeitdetektor ermöglichte dabei, kontinuierliche dE/dx-Kurven über größere Energiebereiche hinweg simultan zu bestimmen. Im Vergleich zu herkömmlichen Meßsystemen, die Ionisationsdetektoren zur Energiemessung verwenden, erlaubten die höhere Energieauflösung und -linearität der CLTDs eine Verringerung der Kalibrierungsfehler sowie eine Erweiterung des zugänglichen Energiebereiches der dE/dx-Messungen in Richtung niedriger Energien. Die gewonnen Daten können zur Anpassung theoretischer und semi-empirischer Modelle und somit zu einer Erhöhung der Präzision bei der Vorhersage spezifischer Energieverluste schwerer Ionen beitragen. Neben der experimentellen Bestimmung neuer Daten wurden das alternative Detektionsprinzip der CLTDs, die Vorteile dieser Detektoren bezüglich Energieauflösung und -linearität sowie der modulare Aufbau des CLTD-Arrays aus mehreren Einzeldetektoren genutzt, um diese Art von Messung auf potentielle systematische Unsicherheiten zu untersuchen. Unter anderem wurden hierbei unerwartete Channeling-Effekte beim Durchgang der Ionen durch dünne polykristalline Absorberfolien beobachtet. Die koinzidenten Energie- und Flugzeitmessungen (E-ToF) wurden weiterhin genutzt, um das Auflösungsvermögen des Detektor-Systems bei der direkten in-flight Massenbestimmung langsamer und sehr schwerer Ionen zu bestimmen. Durch die exzellente Energieauflösung der CLTDs konnten hierbei Massenauflösungen von Delta-m(FWHM) = 1.3 - 2.5 u für 0.1 - 0.6 MeV/u 238U-Ionen erreicht werden. In einer E-ToF-Messung mit Ionisationsdetektoren sind solche Werte in diesem Energie- und Massenbereich aufgrund der Limitierung der Energieauflösung durch statistische Schwankungen von Verlustprozessen beim Teilchennachweis nicht erreichbar.