56 research outputs found

    A Comprehensive Robust Adaptive Controller for Gust Load Alleviation

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    The objective of this paper is the implementation and validation of an adaptive controller for aircraft gust load alleviation. The contribution of this paper is the design of a robust controller that guarantees the reduction of the gust loads, even when the nominal conditions change. Some preliminary results are presented, considering the symmetric aileron deflection as control device. The proposed approach is validated on subsonic transport aircraft for different mass and flight conditions. Moreover, if the controller parameters are tuned for a specific gust model, even if the gust frequency changes, no parameter retuning is required

    Performance of translucent optical networks under dynamic traffic and uncertain physical-layer information

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    This paper investigates the performance of translucent Optical Transport Networks (OTNs) under different traffic and knowledge conditions, varying from perfect knowledge to drifts and uncertainties in the physical-layer parameters. Our focus is on the regular operation of a translucent OTN, i.e., after the dimensioning and regenerator placement phase. Our contributions can be summarized as follows. Based on the computation of the Personick’s Q factor, we introduce a new methodology for the assessment of the optical signal quality along a path, and show its application on a realistic example. We analyze the performance of both deterministic and predictive RWA techniques integrating this signal quality factor Q in the lightpath computation process. Our results confirm the effectiveness of predictive techniques to deal with the typical drifts and uncertainties in the physical-layer parameters, in contrast to the superior efficacy of deterministic approaches in case of perfect knowledge. Conversely to most previous works, where all wavelengths are assumed to have the same characteristics, we examine the case when the network is not perfectly compensated, so the Maximum Transmission Distance (MTD) of the different wavelength channels may vary. We show that blocking might increase dramatically when the MTD of the different wavelength channels is overlooked.Postprint (published version

    Self-attraction effect and correction on three absolute gravimeters

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    The perturbations of the gravitational field due to the mass distribution of an absolute gravimeter have been studied. The so called Self Attraction Effect (SAE) is crucial for the measurement accuracy, especially for the International Comparisons, and for the uncertainty budget evaluation. Three instruments have been analysed: MPG-2, FG5-238 and IMPG-02. The SAE has been calculated using a numerical method based on FEM simulation. The observed effect has been treated as an additional vertical gravity gradient. The correction (SAC) to be applied to the computed g value has been associated with the specific height level, where the measurement result is typically reported. The magnitude of the obtained corrections is of order 1E-8 m/s2.Comment: 14 pages, 8 figures, submitted to Metrologi

    La nandrolona aumenta la actividad de la enzima de conversión angiotensina en tendones de ratones

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    Introdução: O sistema renina-angiotensina (SRA) tem sido associado a importantes processos biológicos do corpo humano, regulando, entre outros processos, a pressão arterial e balanço hidroeletrolítico. Além disso, o SRA também regula o crescimento do tecido conjuntivo. Recentemente, foi demonstrado que a utilização de nandrolona modifica a atividade da enzima conversora de angiotensina (ECA) e aumenta a deposição de colágeno no coração. Objetivo: O objetivo do estudo foi avaliar a atividade de ECA no tendão flexor superficial (TFS) e no soro após exercício de força com administração de esteroides anabólicos androgênicos (EAA) durante sete semanas e após seis semanas de destreinamento. Métodos: Quarenta e oito ratos da linhagem Wistar foram divididos em dois grupos (G1 e G2) e subdivididos em quatro subgrupos: Sedentários (S); treinados (T); sedentários com EAA (EAAS) (Deca-Durabolin - 5mg/kg, duas vezes por semana) e treinados com administração de EAA (EAAT). Os grupos treinados realizaram saltos na água: quatro séries de 10 saltos cada, com intervalo de 30 seg entre as séries. Resultados: O treinamento aumentou a atividade de ECA no TFS em comparação ao controle (p<0,05). Os grupos tratados com EAA apresentaram maiores níveis de ECA (p<0,05). O grupo EAA-T mostrou atividade de ECA mais elevada quando comparada ao grupo T. Além disso, o grupo EAA-T apresentou maiores níveis de ECA no soro. No grupo G2, todos os subgrupos diminuíram a atividade de ECA tanto no soro quanto no tendão. Conclusão: Este estudo indica que a administração de EAA e sua combinação com o exercício aumenta a atividade de ECA nos tendões. O uso abusivo de EAA pode comprometer a adaptação tendínea no qual pode provocar remodelamento mal adaptativas.Introduction: The renin-angiotensin system (RAS) has been associated with several biological processes of the human body, regulating, among others blood pressure and water and electrolytes balance. Moreover, RAS also regulates connective tissue growth. Recently, studies have shown that the use of nandrolone modifies the angiotensin-I converting enzyme (ACE) activity and increases collagen deposition in the heart. Objective: The aim of study was to evaluate the Angiotensin-I converting enzyme (ACE) activity in the superficial flexor tendon (SFT) and in serum after load exercise in combination with anabolic androgenic steroid (AAS) administration after training session and six weeks of detraining. Methods: Forty-eight Wistar rats were used into two groups (G1 and G2) subdivided into four subgroups: Sedentary (S); trained (T); AAS-treated (Deca-Durabolin, 5mg/kg, twice a week) sedentary rats (AAS) and AAS-treated and trained animals (AAST). Trained groups performed jumps in water: four series of 10 jumps each, followed by a 30 sec interval between the series, for seven weeks. Results: Training increased ACE activity in the SFT compared to the control group (p <0.05). Both AAS and AAST groups presented higher ACE activity levels (p < 0.05). The AAST increased the ACE activity only compared to the trained animals. Only the AAST group presented significant higher levels of ACE in the serum. In the G2 group, all experimental groups presented decreased ACE activity in the serum and in the tendon, as compared to the control group. Conclusion: This study indicates that AAS administration and its combination with exercise increased ACE activity of tendons. AAS abuse could compromise tendon adaptation causing maladaptive remodeling.Introducción: El sistema renina-angiotensina (RAS) ha sido asociado con varios procesos biológicos del cuerpo humano, entre ellos, regular la presión arterial y el contenido de electrolitos. Además, el RAS también regula el tejido conectivo. Recientemente, estudios han demostrado que el uso de nandrolona modifica la actividad de ACE e incrementa la deposición de colágeno en el corazón. Objetivo: En este modo, el objetivo del estudio fue evaluar la actividad de la enzima de conversión angiotensina (ACE) en el tendón flexor superficial (TFS) y en el suero después del ejercicio de resistencia en combinación con la administración de esteroides anabólico-androgénicos (AAS) después de la sesión de entrenamiento, y seis semanas de desentrenamiento. Métodos: Cuarenta y ocho ratones Wistar fueron divididos en dos grupos (G1 y G2) y subdivididos en cuatro grupos: sedentarios (S); entrenados (T); ratas sedentarias tretratadas con AAS (Deca-Durabolin - 5 mg / kg dos veces a la semana) (AAS) y animales entrenados y tratados con AAS (AAST). Los grupos entrenados realizaron saltos en el agua: cuatro series de 10 saltos cada uno, con 30 segundos de intervalo entre las series, durante siete semanas. Resultados: El entrenamiento aumentó la actividad de ECA en TFS en comparación con el control (p <0,05). Los grupos AAS y AAST mostraron mayores niveles de ACE (p <0,05). El grupo AAST mostró alta actividad de ECA en comparación con el grupo T. Además, el AAST mostró niveles más altos de ACE en el suero. En G2, todos los grupos disminuyeron la la actividad ACE tanto en el suero como en el tendón si comparados con el grupo control. Conclusión: Este estudio indica que la administración de AAS y su combinación con el ejercicio aumenta la actividad de ECA en los tendones. El uso abusivo de AAS puede comprometer la adaptación del tendón, lo que puede causar remodelaciones mal adaptativas
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