143 research outputs found

    An ECCD—Electronic Charge Compensation Device—As a Quantum Dissipative System

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    An electronic charge compensation device (ECCD) is a passive device that carries electrical currents away, on time, to the electrical Earth field. It prevents lightning’s impacts, derivative electric current pulses, and reduces the radiofrequency disturbances in the protected area. The objective of this paper is to give a physical explanation of the operation of an ECCD’s performance and advantages. The operation of an ECCD is the result of two actions: the static electric field and the evanescent and resonant electrical radiofrequency field in the nearby external adjoining to dielectric-metal zone of ECCD. The energy absorption only is logically justified considering a super-absorption process as an end of chain of resonant quantum event. In this study, a multi-resonant process was inferred from an exhaustive radiofrequency simulation analysis made on an ECCD. The primary experiment was a long-time-frame statistical analysis of seven di_erent, real stations. Those empirical results were derived from real METEORAGE environmental services data. Finally, a prospective for new applications is given

    Detection and measurement of waviness on thin metallic wires

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    We propose a model for determining the far-field diffraction pattern of wires with waviness. Analytical solutions are obtained by means of the stationary phase method, which allows us to determine dimensional parameters such as wire diameter and waviness factor. Experimental results are presented, which are in accordance with our theoretical description

    On the Q(M) depolarization metric

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    In this work, we have derived a depolarization metric, named Q(M) here, from the nine bilinear constraints between the 16 Mueller-Jones matrix elements, reported previously by several authors following different approaches. This metric Q(M) is sensitive to the internal nature of the depolarization Mueller matrix and does not depend on the incident Stokes vector. Q(M) provides explicit information about the inner 3 x 3 internal matrix. Four bounds are associated to Q(All) for a totally depolarizing, partially depolarizing, non-depolarizing diattenuating or partially depolarizing, and non-depolarizing non-diattenuating optical system, respectively. To our best knowledge, Q(All) is the unique depolarization metric that provides such information in one single number

    Analysis of nanostructured porous films by measurement of adsorption isotherms with optical fiber and ellipsometry

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    An optical method to determine the nanostructure and the morphology of porous thin films is presented. This procedure is based on the response of a side-polished optical fiber with the film under study, when an adsorption-desorption cycle is carried out. Spectroscopic ellipsometry provides additional information about the optical properties and adsorption behavior of the film. Pore size distribution, anisotropy, and inhomogeneity of films can be determined by use of these two complementary techniques. To check the performances and suitability of the optical method, we have characterized a typical porous material: a TiO_2 film deposited by evaporation. Water vapor has been used for the adsorption cycles. The well-known columnar structure of the evaporated TiO_2 has been evidenced, and the relation between the nanostructure and the optical properties of the film is showed

    Near field diffraction of cylindrical convex gratings

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    We analyze the field produced by a cylindrical convex diffraction grating at the Fresnel regime for several kinds of light sources, including a monochromatic quasipunctual source, finite size, and polychromatic sources. These results can help one understand the functioning of rotary optical encoder technology. A decrease in the self-image contrast is produced for finite nonpunctual sources. In addition, the polychromaticity of the source affects the smoothness of the self-images, making them quasicontinuous from a certain distance from the grating forward. Finally, we experimentally validate the obtained analytical predictions

    Effect Of Noise In The Estimation Of Magnitudes With Spatial Dependence: A Spatial Statistics Technique Based On Kriging

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    Kriging is a family of linear methods for the estimation of physical quantities with spatial dependence which are optimal in the squared minima sense. To perform the interpolation, kriging considers, in addition to the value and location of the observations, the spatial correlation of the quantity by means of variogram, the random fluctuations of the measured magnitude and the resolution of the measuring devices. The traditional way kriging equations are solved involves the resolution of inverse of great matrices, so that it is normally quite time consuming. Comparing the uncertainty obtained with kriging (for magnitudes with spatial dependence) with standard techniques for uncertainty estimation, we have seen that for the case of regular sampling, the uncertainty estimation can be computed as a convolution

    Uncertainty Estimation by Convolution Using Spatial Statistics

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    Kriging has proven to be a useful tool in image processing since it behaves, under regular sampling, as a convolution. Convolution kernels obtained with kriging allow noise filtering and include the effects of the random fluctuations of the experimental data and the resolution of the measuring devices. The uncertainty at each location of the image can also be determined using kriging. However, this procedure is slow since, currently, only matrix methods are available. In this work, we compare the way kriging performs the uncertainty estimation with the standard statistical technique for magnitudes without spatial dependence. As a result, we propose a much faster technique, based on the variogram, to determine the uncertainty using a convolutional procedure. We check the validity of this approach by applying it to one-dimensional images obtained in diffractometry and two-dimensional images obtained by shadow moire

    Estimation of the standard deviation in three-dimensional microscopy by spatial statistics

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    Usually, the calibration process for three-dimensional microscopy involves the use of a reference flat surface. The random fluctuations of the topographic image for this reference surface are used for determining the uncertainty of the microscope. When the sample material or the measuring conditions of the microscope are modified (such as the objective used in a confocal microscope, or the tip in an atomic force microscope), the measuring conditions vary and thus a new calibration is required. In this work, a technique based on spatial statistics methods (more specifically, the variogram function) is proposed to determine accurately the standard deviation for three-dimensional microscopy that does not require a reference flat surface and therefore eliminates the need for a previous calibration process of this parameter

    Analytical Treatment of Higher-Order Graphs: A Path Ordinal Method for Solving Graphs

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    Analytical treatment of the composition of higher-order graphs representing linear relations between variables is developed. A path formalism to deal with problems in graph theory is introduced. It is shown how paths in the composed graph representing individual contributions to variables relation can be enumerated and represented by ordinals. The method allows for one to extract partial information and gives an alternative to classical graph approach
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