1,721,242 research outputs found
Metodo per la misura di spostamenti angolare e⁄o lineare utilizzante uno o piu' pendoli ripiegati (METHOD FOR THE MEASUREMENT OF ANGULAR AND/OR LINEAR DISPLACEMENTS UTILIZING ONE OR MORE FOLDED PENDULA)
No full textSystems are disclosed for the combined measurement of linear and angular displacements, with high sensitivity, wide measurement band at low frequency based on the configuration of the folded pendulum, and a linear and angular displacement sensor for applications of monitoring and control. Examples of possible applications of the combined sensor subject-matter of the present invention are sensor for the seismic monitoring, sensor for systems of monitoring and/or control of civil and industrial buildings, dykes, bridges, tunnels, etc., sensor for system of monitoring and/or control for the realization of systems of seismic attenuation and inertial platforms
Pendolo ripiegato con bassa frequenza di risonanza ed alto fattore di qualità meccanico in configurazione verticale, e sensore sismico verticale utilizzante tale pendolo ripiegato (LOW FREQUENCY FOLDED PENDULUM AND VERTICAL SEISMIC SENSOR UTILIZING SUCH A FOLDED PENDULUM)
No full textA folded pendulum is described. The folded pendulum can be a monolithic pendulum and is positioned in the vertical configuration. The folded pendulum allows for more compact realizations through high decouplings of a vertical degree of freedom from other degrees of freedom as well as optimal mechanical quality factors
Interferometric Sensor for Seismic Noise Measurement: theoretical model and experimental performances
No full textCompact tunable monolithic sensors for vibration monitoring and control of structures and very low frequency – large band characterization of sites
No full textIn this paper we describe a new mechanical implementation of a horizontal monolithic folded pendulum inertial sensor, configurable as low-frequency large-band seismometer and/or accelerometer, for seismic monitoring (strong motion and seismic noise characterization) and for monitoring and control of scientific, civil and industrial structures, also in difficult environmental conditions (mines, dangerous conditions, high vacuum, low temperature and cryogenic environment). The very large measurement band (〖10〗^(-7)÷10 Hz), low readout noise 1500 in air) are other very relevant features. In the paper, after a general description of the seismometer, we present and discuss preliminary scientific data recorded in the INFN Gran Sasso National Laboratory (LNGS)
A principal components algorithm for spectra normalisation
No full textThere is an increasing use of spectroscopic techniques, such as high-resolution NMR spectroscopy, to examine variations in cell metabolism and/or structure in response to numerous physical, chemical, and biological agents. In these types of studies, in order to obtain relative quantitative information, a comparison between signal intensities of control samples and treated or exposed ones is often conducted. A possible strategy is to estimate, by an opportune algorithm, a normalisation constant which takes into consideration all cell metabolites in the sample. In this paper, a new normalisation algorithm based on Principal Component Analysis (PCA) is presented. PRICONA (PRIncipal COmponent Normalisation Algorithm) is advantageous in normalising simultaneously great data sets of spectra, in individuating signals that could have been affected by the agent, and in allowing to measure their quantitative variation. The algorithm was tested by Monte Carlo simulations as well as experimentally
Neural Network-based approach to noise identification of laser interferometric Virgo Antenna
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Design ad test of an adaptive optics system prototype for laser beam jitters reduction
No full textThis paper reports the experimental results that we have achieved from the tests of characterization of an Adaptive Optics (AO) Prototype implemented in our laboratory in compliance with the statements of the design previously carried out. Our purpose is to check the operation of the AO system that is expected to perform laser beam jitters reduction in the bandwidth of interest of interferometric Gravitational Wave (GW) antennas. Using the correspondence between Hermite Gauss polynomials and Zernike modes that alternatively represent the laser beam perturbations as demonstrated in our previous works, we have designed and implemented an AO system that extracts error signals in terms of Hermite Gauss coefficients and then corrects the wavefront through driver commands sent to the deformable mirror in terms of Zernike profiles. The results here reported confirm effectiveness and robustness of the Prototype which exhibits significant reduction of first and second order laser beam jitters. In particular we have measured the decrease of astigmatism and
defocus modes of 60 dB at low frequency below 1 Hz and of 20 dB up to 200 Hz, which at the best of the present technology fulfils the requirements for noise reduction of the interferometric GW detectors
Watts linkage based large band low frequency sensors for scientific applications
No full textThe UNISA Folded Pendulum class of horizontal and vertical sensors, based on an innovative configuration of the classical Watt׳s linkage mechanical architecture, allows the design and implementation of very large band monolithic sensors (10−7 Hz to10+2 Hz), whose sensitivities for the most common applications are defined by the noise introduced by their readouts (e.g. < 10−12 m/sqrt(Hz) with classical LVDT readouts). These unique features, coupled other relevant properties like scalability, compactness, lightness, high directivity, frequency tunability (typical resonance frequencies in the band (10−1 Hz to 10+2 Hz), very high immunity to environmental noises and low cost make this class of sensors very effective for the implementation of uniaxial (horizontal and/or vertical) and triaxial seismometers and accelerometers for ground, space and underwater applications, including UHV and cryogenics ones
Fractional volume integration in two-dimensional NMR spectra: CAKE, a Monte Carlo approach
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