1,721,394 research outputs found
Enabling FO-Based HUMS Applications Through an Innovative Integration Technique: Application to a Rotor Blade Mockup
No full textAlthough relevant examples of systems devoted to shape sensing, damage detection, load identification, etc., do exist, even based on fiber optic sensors, they are barely suited for installation on real aerospace applications due to important criticalities in the application of the fiber. However, all HUMS application based on fiber optics can be enabled thanks to the proposed Smart Veil: a technology consisting of a thin composite membrane incorporating fiber optics placed on a complex path. This integrated element makes the monitoring system easy to use/handle, robust and reliable in real operating scenarios, capable of guaranteeing precise measurements. The effectiveness of this technological solution is proven by means of the manufacturing of a sensorized helicopter blade mockup. Among the several techniques that can be adopted using a fiber optic, FBG (Fiber Bragg Grating) sensors have been selected, allowing a robust punctual measure in specific locations. The choice of sensors position was led by the idea to exploit a digital twin for shape reconstruction and load identification, so all the components of the relevant loads acting on a tail rotor blade during operation can be obtained: axial, beam bending, chord bending and torsion. All sensors benefit from the use of the smart veil that guarantees robust and precise measures. Particularly, the torsional sensors do, since they need to be placed on an ad hoc path. The static calibration test and a comparison with a strain gauges system permitted a validation and showed the advantages of the technological solution proposed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Thin membranes based on FBG sensors for real-time sub-bandage pressure monitoring
Full text linkThis work focuses on the manufacturing and testing of a new device for medical bandage monitoring. Excessive pressure exerted from the compression bandage can block the blood flow of the patient, causing different medical complications to the skin, nerves, and circulatory system. On the contrary, if the pressure applied is low, the therapy is not effective. The utility, therefore, arises from a device capable of quantitatively indicating the correct adjustment of the bandage. The technological demonstrators developed consist of a polyurethane elastomeric shell with a thin composite supporting core. Fiber Bragg grating sensors (FBGSs) embedded within this core permit the detection of the subbandage pressure applied during compression therapy. The two prototypes were applied under arm bandages to evaluate their capability to transmit the applied pressure to the embedded FBGS. We demonstrated the ability to monitor the bandaging action by measuring the level of pressure exerted with the rounds of bandages. Moreover, the thin membranes permit the monitoring of the heartbeat of the patient, giving feedback about blood irrotation. The device developed is, therefore, promising to improve the results of compression therapy
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
An Integrated Fiber Optic Based SHM System for Structural Composite Components: Application to a Racing Motorbike Fork
No full textThe aim is to create a smart structure holding the benefits of a structural monitoring system combined with the high performance of composite materials in a key component of a racing motorcycle, that is the front fork. Telescopic forks in composite material allow mass reduction while maintaining adequate stiffness, even if their use is currently limited only to a niche of applications, mainly for wear issues. Here, the fork tube was designed, optimizing the lamination sequence to replicate the stiffness of the original fork. The applied monitoring system uses optical fibers, for which composites are an excellent host material, with Bragg grating sensors. From the deformations measured is possible to derive information on the integrity, to set the performance of stiffness and to detect the loads. Given the difficulties in the correct positioning of the sensors (diametrically opposite on a cylindrical surface) and to imagine an effective use during racing, the need was highlighted to implement a system allowing a safe, easy, and precise positioning of the optical fiber on a predetermined path between the composite layers and the proper housing of the relative connector. The fork tube equipped with the smart veil was made by autoclave forming and then tested in the laboratory both alone and mounted on the bike. The result is a component whose deformations are known in real time, that integrates adequately protected and well-placed sensors, that are linked to the acquisition by means of a connector embedded directly into the structure itself
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