Impact of a heterogeneous stator on the rotor-stator interaction-noise: an analytical, experimental and numerical investigation

La présente étude vise à quantifier par une modélisation analytique, des essais et des simulations numériques, l’impact d’un stator hétérogène sur le bruit d’interaction rotor-stator dans les turbomachines axiales. Le travail développé s’appuie sur des premières observations sur un ventilateur axial à basse vitesse à l’École Centrale de Lyon, l’étage LP3. Il a été observé que les deux premières fréquences de passage des pales (FPP) rayonnaient à des niveaux élevés alors qu’elles devaient être coupées par le conduit selon le critère de Tyler & Sofrin. Une campagne expérimentale est alors réalisée sur la configuration de ventilateur hétérogène qui permet la caractérisation des contenus spectral et modal. Afin de s’assurer qu’aucune distorsion d’entrée d’air n’est présente, un écran pour le contrôle de la turbulence est utilisé. Des techniques de décomposition modale sont utilisées sur des antennes pseudo-aléatoires afin d’obtenir les modes acoustiques prédominants. Les résultats montrent un fort rayonnement acoustique des deux premières fréquences de passage des pales et mettent en évidence des modes dominants. La même expérience est ensuite simulée numériquement en utilisant la méthode de Boltzmann sur réseau. Les simulations montrent un bon comportement de la turbomachine mais prédisent une augmentation de pression inférieure à celle de l’expérience. La comparaison entre un stator homogène et hétérogène permet de quantifier directement l’impact de l’hétérogénéité. L’hétérogénéité est alors responsable d’une augmentation du niveau tonal de plus de 10 dB aux deux premières FPP. Le contenu modal mesuré sur la configuration hétérogène est bien retrouvé par les simulations numériques. En outre, l’analyse de l’écoulement dans l’espacement inter-rotor-stator a permis de mettre en évidence l’impact de l’hétérogénéité sur le champ potentiel. Finalement, la modélisation analytique est axée sur deux sources dominantes : le bruit d’interaction de sillages et le bruit d’interaction potentielle. Les résultats montrent une contribution mineure de ce dernier. Les mêmes modes dominants sont retrouvés dans certaines directions de propagation en accord avec ce qui est observé expérimentalement. En dernier lieu, une étude d’optimisation de la position des bras support est présentée. Une des configurations optimales montrant une forte atténuation du niveau de bruit tonal est validée numériquement par des simulations numériques. Les résultats montrent que l’optimisation du positionnement angulaire des aubes structurelles permet d’obtenir une réduction significative des niveaux aux deux premières FPP. L’étude des différentes composantes (analytique, expérimentale et numérique) fournit ainsi une meilleure compréhension des mécanismes de bruit modifiés par l’hétérogénéité du stator.Abstract: The present study aims to quantify by means of analytical modelling, experiments and numerical simulations, the impact of a heterogeneous stator on the rotor-stator noise in axial turbomachines. This study starts with the first observations on an axial low-speed fan at École Centrale de Lyon, the LP3 stage. It has been observed that the first two blade passing frequencies (BPF) were radiating at high levels while they were expected to be cut-off by the duct according to Tyler & Sofrin’s criterion. An experiment is then carried out with the heterogeneous stator configuration which makes it possible to characterize the spectral and modal contents. To ensure that no inflow distortion is present at the inlet, a Turbulence Control Screen is used. Modal decomposition techniques are used with pseudo-random antennas to obtain the predominant acoustic modes. Results show a strong acoustic radiation of the first two BPFs and evidence some dominant modes. The same experiment is then simulated numerically using the lattice Boltzmann method. The simulations show a good physical behaviour of the turbomachine but predict a lower pressure-rise compared with the experiment. The comparison between homogeneous and heterogeneous stators allows quantifying directly the impact of the heterogeneity. The heterogeneity is responsible for a level increase of more than 10 dB at the first two BPFs. The modal content from the numerical simulations on the heterogeneous configuration is also in good agreement with the experiment. In addition, the analysis of the flow in the inter-stage made it possible to highlight the impact of the heterogeneity on the potential field. Finally, the analytical modelling is focused on two dominant sources: wake-interaction noise and potential-interaction noise. Results put in evidence a minor contribution of the latter despite the short rotor-stator spacing. The same dominant modes are found in certain propagation directions in accordance with what is measured in the experiment. Finally, an optimisation of the modified vanes angular position is carried out. One of the optimal configurations showing a great noise attenuation is numerically validated by the LBM. The numerical results show that the optimisation of the azimuthal positioning of the modified vanes makes it possible to obtain a significant reduction of the levels at the first two BPFs. Thereby, the comparison of the analytical, experimental and numerical investigations allows achieving a better understanding of the modification of noise mechanisms caused by the heterogeneity of the stator

A JML-Based strategy for incorporating formal specifications into the software development process

This thesis presents a JML-based strategy that incorporates formal specifications into the software development process of object-oriented programs. The strategy evolves functional requirements into a “semi-formal” requirements form, and then expressing them as JML formal specifications. The strategy is implemented as a formal-specification pseudo-phase that runs in parallel with the other phase of software development. What makes our strategy different from other software development strategies used in literature is the particular use of JML specifications we make all along the way from requirements to validation-and-verification.Orientador: Néstor Catañ

Influence of slaughter season, muscle type and gluconeogenesis precursors on intramuscular fat quality of ruminant meats

Tese de Doutoramento em Ciências Veterinárias, especialidade de Segurança AlimentarThe aim of this study was to determine the influence of slaughter season and muscle type on nutritional quality of intramuscular fat (IMF) in Mirandesa-PDO (Protected Designation of Origin) veal, Charneca-PDO beef and organic beef, assessing to the quality and status that may contribute to market differentiation. The results suggest that the IMF content of PDO veal, PDO beef and organic beef was slightly affected by the slaughter season but markedly changed by the muscle type. The meat analysed had a high nutritional value, with favourable ratios of n-6/n-3 and contents of n-3 PUFA and α-tocopherol. Some studies indicate that increasing the stearoyl-CoA desaturase (SCD) expression and activity may significantly improve the nutritional quality of meat by decreasing the SFA content, while increasing rumenic acid content. This can be achieved by the administration of gluconeogenesis precursors, such as propylene glycol, which induces elevated propionate in the rumen and higher levels of blood insulin and glucose, resulting in the SCD activity elevation. Thus, the influence of dietary gluconeogenesis precursors (propylene glycol and calcium propionate mix; PP) and linseed oil on intramuscular fatty acid composition of lambs was assessed. Results suggest that gluconeogenesis precursors modify the biohydrogenation pathway and reduce the rumenic acid concentration. Linseed oil supplementation increased meat concentration of α-linolenic acid, as well as most of the C18 biohydrogenation intermediates, including vaccenic acid and rumenic acids. In conclusion, regarding the lipid composition of IMF, the studied PDO and organic meats have a high nutritional value, contributing to the consumer`s confidence on these products. The fatty acid profile of lamb’s IMF was slightly affected by PP, without clear effects on insulinaemia and delta-9 desaturation, demanding future research on this subject.RESUMO - Influência da sazonalidade, do tipo de músculo e de precursores da neoglucogénese na qualidade da gordura intramuscular de carne de ruminantes - Neste trabalho estudou-se o efeito da sazonalidade do abate e do tipo de músculo na qualidade da gordura intramuscular das carnes Mirandesa-DOP (Denominação de Origem Protegida) e Charneca-DOP, e da carne biológica, de modo a avaliar a qualidade e reputação alegada como fator diferenciador no mercado. Os resultados sugerem que a composição de ácidos gordos da gordura intramuscular das carnes analisadas foi influenciada ligeiramente pela sazonalidade do abate mas fortemente pelo tipo de músculo. Apesar desta variação, todas as carnes analisadas têm um elevado valor nutricional apresentando um índice favorável n-6/n-3 e teores elevados de n-3 PUFA e α-tocoferol. Alguns estudos indicam que o aumento da atividade da Δ-9 dessaturase pode melhorar a qualidade nutricional da carne, através da diminuição dos ácidos gordos saturados e do aumento do teor de ácido ruménico. Isto pode ser possível pela administração de precursores neoglucogénicos, tais como o propilenoglicol que induz o aumento do propionato no rúmen e aumenta os níveis sanguíneos de insulina e glucose, resultando no aumento da atividade da Δ-9 dessaturase. Assim foi avaliado o efeito da suplementação da dieta com propilenoglicol e propionato de cálcio, bem como óleo de linho, na composição lipídica da gordura intramuscular da carne de borrego. Os resultados sugerem que os precursores neoglucogénicos alteram a biohidrogenação ruminal e diminui o teor de ácido ruménico. A suplementação com óleo de linho aumenta o teor de ácido α-linolénico da carne, bem como a maioria dos C18 intermediários da biohidrogenação, incluindo os ácidos vacénico e ruménico. Em conclusão, a composição lipídica da gordura intramuscular das carnes de bovino DOP estudadas e da carne biológica apresenta um elevado valor nutricional, contribuindo para confiança do consumidor sobre estes produtos O perfil dos ácidos gordos da gordura intramuscular da carne de borrego é ligeiramente influenciado pelos precursores, sem efeitos claros na insulinemia e na Δ-9 dessaturase, exigindo-se estudos futuros sobre este assunto.FCT - SFRH/PROTEC/2009/50138 and Co-financed by the grant PTDV/CVT/2006/6611

A venda a retro como instrumento de concessão de crédito garantido : do direito civil ao direito bancário

Contrato de compra e venda / Garantia de crédit

A productivity dashboard for hospitals: An empirical study

Health units are institutions which require accurate, updated information to support managerial decisions for thriving in such a critical industry. Thus, health information systems have been developed to help hospital managers steer daily operations. These systems provide not only operational support, but also key performance indicators (KPI’s) to monitor relevant areas at a time-aggregated basis. Despite the recognized value of dashboards in helping decision-makers, the literature shows a lack of proposals of productivity dashboards to assist Hospitals stakeholders. The thesis focuses on two problems: Hospital organizations need access to production and productivity information to improve access to services. Managers need production and productivity information to optimize resource allocation. The importance of addressing these issues lies in the fact that to monitor production and productivity information, is it possible to improve resource allocation. This dissertation consists of the development of dashboards to monitor information obtained from a hospital organization at the level of production and productivity, with the mission of supporting decision makers in the decision process. To properly develop the productivity dashboard, the Design Science Research (DSR) methodology was adopted to build and evaluate the artefact. It was ascertained that the production and productivity segment need more study and that the dashboards on these themes is an asset at the level of monitoring and analysis and subsequent decision-making process. The expected contribution of this research is to develop a dashboard recognized by health stakeholders as capable of better assisting them during their management duties.As unidades de saúde são instituições que requerem informações atualizadas e precisas para apoiar as decisões de gestão a fim de prosperarem numa indústria tão crítica. Assim, os sistemas de informação de saúde foram desenvolvidos para ajudar os gestores hospitalares a dirigir as operações diárias. Esses sistemas não fornecem só suporte operacional, mas também indicadores de desempenho chave (KPI’s) para monitorizar áreas relevantes numa base agregada no tempo. A tese concentra-se em dois problemas: As organizações hospitalares precisam de informações sobre produção e produtividade para melhorar o acesso aos serviços. Os gestores precisam de informações de produção e produtividade para otimizar a alocação de recursos. A importância da resolução destas questões prende-se com o facto de que ao monitorizar a informação de produção e produtividade é possível melhorar a alocação de recursos. A pesquisa consiste no desenvolvimento de painel de controlo para monitorar as informações obtidas numa organização hospitalar ao nível da produção e produtividade, com a missão de apoiar os decisores no processo de decisão. Para desenvolver adequadamente o painel de controlo de produtividade, adotou-se a metodologia Design Science Research (DSR) para construir e avaliar o artefato. Verificou-se que o segmento de produção e produtividade necessita de mais estudo e que o painel de controlo sobre estas temáticas é uma mais-valia ao nível da monotorização e análise e posterior processo de tomada de decisão. O contributo esperado é melhorar o processo de tomada de decisão nas Organizações de saúde, podendo ser útil para alertar de factos que a própria organização possa ainda desconhecer relativamente à sua operacionalidade

As garantias difusas do financiamento societário: as cartas de conforto

O tráfico mercantil está constantemente a gerar novos instrumentos que melhor se adaptam às necessidades que aí se fazem sentir. Um deles, ligada à concessão do crédito societário, são as cartas de conforto. Ao contrário das diferentes modalidades de garantias pessoais, elas têm um caráter difuso, o que torna difícil a sua qualificação. Para o efeito, recorremos à criação de grupos de cartas de conforto, apurando o seu regime geral. Dentro desse quadro torna-se possível proceder depois à determinação do regime de cada carta em concreto. SUMÁRIO: 1. Introdução 2. A razão de ser 3. A juridicidade 4. A estrutura 5. Modalidades 5.1. As cartas fracas com conteúdo meramente informativo 5.2. As cartas médias que contêm declarações de vigilância, influência ou de empenho 5.3. As cartas fortes ou de garantia 6. O regime insolvencial Bibliografia Jurisprudênci

O DEVER DE GESTÃO PROCESSUAL NO CÓDIGO DE PROCESSO CIVIL DE 2013

ABSTRACT The Duty of Procedural Management is, in terms of judicial practice, a transformation of culture that depends on judges with good technical and human preparation, it is also necessary that they may have time for them to study the process, so that they can decide the best process management to give the specific case. Judges have a duty to use the powers available to them under the Duty of Procedural Management, but also should not pass. In this article we begin by addressing the notion of duty of Procedural Management, then follow with the implementation of such duties. Later we focused on the no appeal decisions of simplification decisions or procedural streamlining and then the healing of lack of assumptions with the invocation of a particular case, ending with the conclusions.KEYWORDS: Duty of Procedural Management; Judge` Management Powers, No Appea

Heart rate variability and erectile function in younger men: A pilot study

Erectile dysfunction (ED) in younger men is an increasing concern. In middle aged and older men, ED was related to lower resting heart rate variability (HRV), but research in younger men is lacking. The present study examined, in a nonclinical sample of 105 men between 18 and 39 years, the association of ED with several parameters of resting HRV. Scores of the 5-item version of the International Index of Erectile Function (IIEF-5) below 22 were considered as indicating ED. Eighteen men (17.1%) reported ED (mild in 16, mild to moderate in 2). Welch's tests revealed that ED was associated with lower low-frequency power (LF), lower high-frequency power (HF), lower standard deviation of interbeat intervals, and lower standard deviation of the heart rate, which is influenced by both sympathetic and parasympathetic activity. After removing outliers, ED was unrelated to HF. In younger men, erections might be facilitated by a combination of higher parasympathetic tone and relatively higher sympathetic tone in the heart, as indicated by LF and greater standard deviation of the heart rate, a largely overlooked parameter in HRV research.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio