95 research outputs found

    Aeroelastic implications of active winglet concept aimed to improve civil transport aircraft performances

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    Reduction of aircraft environmental footprint has become over years a key objective for the industry. Particularly, for decades winglets have been proven to eficiently reduce drag and fuel consumption. However, the design of those wingtip extensions mainly relies on an aerodynamic shape optimisation for a given cruise condition resulting in suboptimal behaviour for the rest of the flight. Active winglet concept proposes to optimise the winglet cant angle along the flight to compensate the loss of eficiency inherent to fixed designs. The variation of winglet deflection impacts the lift distribution with repercussion on wing deformation that must be investigated. Besides, the presence of moving masses at the tip of the wing also has influence on dynamic response and particularly on flutter onset. This work proposes to evaluate those impacts through an aeroelastic analysis of both static and dynamic implications of active winglets combined with an aerodynamic performances optimisation. The XRF1, an Airbus provided industrial standard multi- disciplinary research test case representing a typical configuration for wide body long- range aircraft, is used as the baseline aircraft. Coupled CFD/CSM computations are performed to assess the evolution of wing shape with respect to winglets deflections and the consequences on mission performance optimisation. While a parametric flutter analysis is carried-out to highlight the dependence of critical flutter speed on winglet cant angle

    Aided Inertial Estimation of Wing Shape

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    Advanced large-wing-span aircraft result in more structural flexibility and the potential for instability or poor handling qualities. These shortcomings call for stability augmentation systems that entail active structural control. Consequently, the in-flight estimation of wing shape is beneficial for the control of very flexible aircraft. This paper proposes a new methodology for estimating flexible structural states based on extended Kalman filtering by exploiting ideas employed in aided inertial navigation systems. High-bandwidth-rate gyro angular velocities at different wing stations are integrated to provide a short-term standalone inertial shape estimation solution, and additional low-bandwidth aiding sensors are then employed to bound diverging estimation errors. The proposed filter implementation does not require a flight dynamics model of the aircraft, facilitates the often tedious Kalman filtering tuning process, and allows for accurate estimation under large and nonlinear wing deflections. To illustrate the approach, the technique is verified by means of simulations using sighting devices as aiding sensors, and an observability study is conducted. In contrast to previous work in the literature based on stereo vision, a sensor configuration that provides fully observable state estimation is found using only one camera and multiple rate gyros for Kalman filtering update and prediction phases, respectively

    LISA test mass charging process due to cosmic ray nuclei and electrons

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    none10noolar energetic particles and galactic cosmic rays with energies larger than 100 MeV cause progressive charging of the LISA experiment test masses. Consequently, Coulomb forces occur between the test masses and the surrounding conducting surfaces generating spurious signals that might be mistaken for gravitational wave signals. We have parametrized the energy spectra of galactic cosmic-ray nuclei and electrons near the LISA orbit in order to evaluate their role in the test-mass charging relative to the most abundant proton component. This work has been carried out using the FLUKA Monte Carlo program.openC. GRIMANI; H. VOCCA; G. BAGNI; L. MARCONI; R. STANGA; F. VETRANO; A. VICERÉ; P. AMICO; L. GAMMAITONI; F. MARCHESONIGrimani, Catia; H., Vocca; G., Bagni; L., Marconi; R., Stanga; Vetrano, Flavio; Vicere', Andrea; P., Amico; L., Gammaitoni; F., Marcheson

    Whirl tower demonstrations of the SHARCS hybrid control concept

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    Abstract Elements of the SHARCS (Smart Hybrid Active Rotor Control System) Hybrid Control concept are demonstrated via two sets of whirl tower tests. Hybrid Control stands for combining a flow control (such as an Actively Controlled Flap or Active Twist Rotor) and of a structural (or stiffness) control device on a helicopter blade. A Hybrid Control system promises to reduce vibration and noise on helicopters simultaneously as well as to improve the efficiency of the flow control device. For the structural control system, a unique and entirely original Active Pitch Link has been developed at Carleton University, which is capable of dynamically controlling the torsional stiffness of a blade. Design, prototyping, static and whirl tower testing of this device is presented in the paper. A second set of whirl tower tests of an Active Twist Rotor equipped with a range of springs instead of the conventional pitch link, demonstrates that the Active Pitch Link shall indeed be capable of lowering the torsional stiffness of the blade. For these tests, the modal parameters of the blade were evaluated via a novel "Output-Only" method, which represents the first application of such methodology for rotary-wing applications

    Thermal noise reduction for present and future gravitational wave detectors

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    Thermal noise in mirror suspension is and will be the most severe fundamental limit to the low-frequency sensitivity of interferometric gravitational wave detectors currently under construction. The technical solutions, adopted in the Virgo detector, optimize the current suspension scheme, but new materials and new designs are needed to further reduce the suspension thermal noise. Silicon fibers are promising candidates both for room temperature advanced detectors and for future cryogenic interferometric detectors

    Monocrystalline fibres for low thermal noise suspension in advanced gravitational wave detectors

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    Thermal noise in mirror suspension will be the most severe fundamental limit to the low-frequency sensitivity of future interferometric gravitational wave detectors. We propose a new type of materials to realize low thermal noise suspension in such detectors. Monocrystalline suspension fibres are good candidates both for cryogenic and for ambient temperature interferometers. Material characteristics and a production facility are described in this paper

    Measurement of the thermoelastic properties of crystalline Si fibres

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    In order to reduce the thermal noise in future interferometers for gravitational wave (GW) detectors, new suspension materials with low thermal noise are under investigation. Crystalline silicon seems to be a promising material mainly at low temperature. A new technology to produce crystalline silicon fibres has been realized. Measurements of mechanical and thermal properties of the fibres at room temperature have been performed. Preliminary measurements at low temperature are presented

    Clinical Features, Cardiovascular Risk Profile, and Therapeutic Trajectories of Patients with Type 2 Diabetes Candidate for Oral Semaglutide Therapy in the Italian Specialist Care

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    Introduction: This study aimed to address therapeutic inertia in the management of type 2 diabetes (T2D) by investigating the potential of early treatment with oral semaglutide. Methods: A cross-sectional survey was conducted between October 2021 and April 2022 among specialists treating individuals with T2D. A scientific committee designed a data collection form covering demographics, cardiovascular risk, glucose control metrics, ongoing therapies, and physician judgments on treatment appropriateness. Participants completed anonymous patient questionnaires reflecting routine clinical encounters. The preferred therapeutic regimen for each patient was also identified. Results: The analysis was conducted on 4449 patients initiating oral semaglutide. The population had a relatively short disease duration (42%  60% of patients, and more often than sitagliptin or empagliflozin. Conclusion: The study supports the potential of early implementation of oral semaglutide as a strategy to overcome therapeutic inertia and enhance T2D management

    Strategies for preventing group B streptococcal infections in newborns: A nation-wide survey of Italian policies

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    Cancer data quality and harmonization in Europe: the experience of the BENCHISTA Project – international benchmarking of childhood cancer survival by stage

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    IntroductionVariation in stage at diagnosis of childhood cancers (CC) may explain differences in survival rates observed across geographical regions. The BENCHISTA project aims to understand these differences and to encourage the application of the Toronto Staging Guidelines (TG) by Population-Based Cancer Registries (PBCRs) to the most common solid paediatric cancers.MethodsPBCRs within and outside Europe were invited to participate and identify all cases of Neuroblastoma, Wilms Tumour, Medulloblastoma, Ewing Sarcoma, Rhabdomyosarcoma and Osteosarcoma diagnosed in a consecutive three-year period (2014-2017) and apply TG at diagnosis. Other non-stage prognostic factors, treatment, progression/recurrence, and cause of death information were collected as optional variables. A minimum of three-year follow-up was required. To standardise TG application by PBCRs, on-line workshops led by six tumour-specific clinical experts were held. To understand the role of data availability and quality, a survey focused on data collection/sharing processes and a quality assurance exercise were generated. To support data harmonization and query resolution a dedicated email and a question-and-answers bank were created.Results67 PBCRs from 28 countries participated and provided a maximally de-personalized, patient-level dataset. For 26 PBCRs, data format and ethical approval obtained by the two sponsoring institutions (UCL and INT) was sufficient for data sharing. 41 participating PBCRs required a Data Transfer Agreement (DTA) to comply with data protection regulations. Due to heterogeneity found in legal aspects, 18 months were spent on finalizing the DTA. The data collection survey was answered by 68 respondents from 63 PBCRs; 44% of them confirmed the ability to re-consult a clinician in cases where stage ascertainment was difficult/uncertain. Of the total participating PBCRs, 75% completed the staging quality assurance exercise, with a median correct answer proportion of 92% [range: 70% (rhabdomyosarcoma) to 100% (Wilms tumour)].ConclusionDifferences in interpretation and processes required to harmonize general data protection regulations across countries were encountered causing delays in data transfer. Despite challenges, the BENCHISTA Project has established a large collaboration between PBCRs and clinicians to collect detailed and standardised TG at a population-level enhancing the understanding of the reasons for variation in overall survival rates for CC, stimulate research and improve national/regional child health plans
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