306 research outputs found

    Three-region inequalities for the second order elliptic equation with discontinuous coefficients and size estimate

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    In this paper, we would like to derive a quantitative uniqueness estimate, the three-region inequality, for the second order elliptic equation with jump discontinuous coefficients. The derivation of the inequality relies on the Carleman estimate proved in our previous work. We then apply the three-region inequality to study the size estimate problem with one boundary measurement.Comment: 16 pages, 1 figur

    Method and System for Synchronizing Electronic Program Guides

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    A method (500) for generating a time scheduling (150) of a contents stream (140) distributed to a plurality of terminals (120) is provided. The contents stream is segmented in consecutive segments, each segment defining a corresponding program (Pi). The method includes receiving auxiliary meta data comprising a planned time scheduling of the content stream which has been set in advance and monitoring at least a portion of a segment of the contents stream to extract corresponding content features there from. The method further includes generating a corresponding fingerprint based on the extracted content features and assessing at least one among an actual start time and an actual end time of such segment based on a comparison between said fingerprint and a reference fingerprint associated with such segment. The method still further includes updating the planned time scheduling based on the assessed at least one among the actual start time and the actual end time so as to generate a time scheduling synchronized with the contents stream

    Ultrasonic techniques for repair of aircraft structures with bonded composite patches

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    This is a paper on a research and development project to demonstrate a novel ultrasonic process for the field application of boron/epoxy (B/Ep) patches for repair of aircraft structures. The first phase of the project was on process optimization and testing to develop the most practical ultrasonic processing techniques. Accelerated testing and aging behavior of precured B/Ep patches, which were ultrasonically bonded to simulated B-52 wing panel assemblies, were performed by conducting flight-by-flight spectrum loading fatigue tests. The spectrum represented 2340 missions/flights or 30 years of service. The effects of steady-state applied temperature and prior exposure of the B/Ep composite patches were evaluated. Representative experimental results of this phase of the project are presented

    VUV-Vis optical characterization of Tetraphenyl-butadiene films on glass and specular reflector substrates from room to liquid Argon temperature

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    The use of efficient wavelength-shifters from the vacuum-ultraviolet to the photosensor's range of sensitivity is a key feature in detectors for Dark Matter search and neutrino physics based on liquid argon scintillation detection. Thin film of Tetraphenyl-butadiene (TPB) deposited onto the surface delimiting the active volume of the detector and/or onto the photosensor optical window is the most common solution in current and planned experiments. Detector design and response can be evaluated and correctly simulated only when the properties of the optical system in use (TPB film + substrate) are fully understood. Characterization of the optical system requires specific, sometimes sophisticated optical methodologies. In this paper the main features of TPB coatings on different, commonly used substrates is reported, as a result of two independent campaigns of measurements at the specialized optical metrology labs of ENEA and University of Tor Vergata. Measured features include TPB emission spectra with lineshape and relative intensity variation recorded as a function of the film thickness and for the first time down to LAr temperature, as well as optical reflectance and transmittance spectra of the TPB coated substrates in the wavelength range of the TPB emission
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