1,721,003 research outputs found
Space-Filling Electromagnetic Skins for the Wireless Monitoring of Surface Defects
No full textPolymer-based objects (cable harness, gaskets, tires) are exposed, during their lifetime, to mechanical and chemical stress that often generates surface defects like crack and scratches. Early detection of signs of aging may enable a Predictive Maintenance to extend the life of the object and avoid severe failures. For this purpose, Space Filling Curves (SFC) are here proposed as an artificial electric skin, suitable to envelope a surface to wireless detect the presence of small aging signs by resorting to an electromagnetic backscattering platform. Size and resolution of the skin can be controlled by just two parameters and multiple skin cells can be arranged together to tessellate a large surface in order to even identify the position of the defect. By following a theoretical analysis of the sensor-oriented properties of SFCs, and in particular of the Gosper-Fukuda family, the feasibility of the idea is demonstrated by the way of preliminary experiments with a Radio Frequency Identification (RFID) IC, providing a 1-bit anti-tamper port
Inkjet-Printed RFID-Skins for the Detection of Surface Defects
No full textThe aging of polymer-based objects (tires, cable harness, paints, gaskets) may appear as the formation of surface defects like cracks and scratches. An early detection of such signs may support the Predictive Maintenance of critical polymeric devices before the occurrence of a severe damage. Inkjet printed Space Filling Curves (SFC) are here proposed as an artificial electric skin, suitable to be integrated with an RFID tag, at the purpose to detect and remotely transmit the presence of small aging signs of a surface. Thanks to the particular properties of the Gosper SFC, the size and space resolution of the skin can be easily controlled by few parameters. The idea is corroborated by preliminary experimentations with low-cost inkjet printed traces that easily enable to monitor the presence of a defect from a distance of 10 m and more
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
Potentiometric Sensing by means of Self-tuning RFID ICs
No full textRecently introduced autotuning RFID ICs can provide digital information on the change in the local boundary conditions in the close surrounding of the tag. By exploiting this feature in combination with a varactor diode, a general framework for the controlled sensing of a chemical agent can be achieved. The varactor acts as a transducer converting the potentiometric output of a chemical sensor into a capacitance change that produces in turn a mismatch between the antenna and the IC. Closed-form expressions relate the digital output of the IC to said chemical variation so that it is well mapped within the retuning dynamic range. The method is demonstrated with reference to a pH sensor and looks promising to provide a sensitivity of 18 units per unitary change of the pH and could be read up to 2 m
Orthopedic fixture-integrated RFID temperature sensor for the monitoring of deep inflammations
No full textOrthopedic implants could be subjected to infections. Conventional diagnostic tools involve X-Rays, MRI, CT imaging or, more commonly, the onset of the patient's pain. Monitoring the health state of a prosthesis from the outside the limb can be accomplished by through-the-body wireless communication link. However, techniques for integrating a wireless sensor into orthopedic implants require a structural modification of the prosthesis. To overcome this limitation, a non-invasive way to augment a prosthesis with wireless monitoring capability is here proposed for the early detection of local tissue infection. The idea can be applied to an orthopedic fixation plate provided with holes, with no changes to its structure. The fixation bar is transformed into an RFID tag by exciting voltage gap into an unused screw hole. The electrical and geometrical parameters of the exciter enable a convenient two-steps tuning mechanism (coarse and fine) to adjust the working frequency. Preliminary simulations predicted a read range of more than 50 cm outside the body that is suited to an early and non-collaborative diagnosis in the emerging Personalized Healthcare
Gosper Space-Filling Radiofrequency-Skin for the Detection and Identification of Surface Cracks
No full textConformal Space-Filling Electromagnetic Skins for the Wireless Monitoring of 3D Object Integrity
No full textThe widespread use of polymer-based objects such as pipes, cables, tiles, gaskets in a wide range of applications demands for large scale a regular monitoring of their health status in order to prevent potential failures during service. Indeed, the exposure of these objects to mechanical or chemical stressing agents may accelerate their aging process thus decreasing their natural lifetime. A non-invasive and early monitoring of these aging signs (such as surface defects) may enable a predictive maintenance in order to avoid, or at least to minimize, unexpected failures.This paper describes a wireless crack detection method based on space-filling curves working like an electromagnetic second-skin enveloping the object. The conformal sensor permits to remotely transmit the presence of small defects over the object by using Radio Frequency Identification antennas and microchip transponders provided with anti-tampering features. The proposed idea is corroborated by numerical modeling and by some experimentations with a plastic pipe joint coated by a three-cells sensing skin made by silver conductive paint that is suitable to enable a wireless robust crack detection system up to 1.5m distance
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
Antennifying Orthopedic Bone-Plate Fixtures for the Wireless Monitoring of Local Deep Infections
No full textInfection is the unavoidable threat to any orthopedic implant that can also force its removal as extreme remedy. The diagnosis of infections is currently achieved by time consuming imaging (X-Rays, MRI, CT) or just by the onset of the patient's pain, when the problem is in an advanced status. Instead, by equipping the prosthesis with a local sensor (for the temperature as a first) and with a wireless communication radio, an early-time identification of the infection could be achieved. This paper proposes a method to transform an orthopedic device provided with holes (like a bone fixation plate) into an harvesting antenna integrating an RFID sensor, with no battery onboard. A miniaturized antenna adapter, fully embedded into a free hole, with tuning capability, collects the electromagnetic power intercepted by the medical device and transfers it to the RFID circuit. Simulations and experimentations with several prototypes demonstrated that the augmented implanted device can establish a stable RFID link up to 0.5 m and that it is able to correctly sample the variation (37°C - 40°C) of the local temperature of the bone as in case of typical deep infections
- …
