87,797 research outputs found
L’anemia nelle infezioni
No full textL'anemia è usualmente osservata nelle infezioni gravi, croniche, infiammatorie e neoplastiche. E' evidenziato il ruolo delle citochine nella patogenesi dell'anemia nelle malattie corniche
Smart fault-tolerant air-data sensor for aircraft flow angles measurement
No full textThis paper deals with the development of a smart multi-hole probe for aircraft air data sensing. The system aims at the calculation of static and total pressures, the angle-of-attack and the angle-of-sideslip starting from the elaboration of the pressure measurements on holes. The probe is characterized by fault-tolerant capabilities with respect to the loss of pressure data, and it is developed as an embedded system including MEMS sensors and a control electronics for multiple reconstructions of flow measurements. The basic idea for the reconstruction algorithm is that, for typical aircraft envelopes, flow angles are small (<15° for both attack and sideslip), and the shape of the pressure field around the stagnation point of a hemispherical body is essentially independent from the flow angles. Thus, once characterised the flow at the aircraft installation for zero angles of attack and sideslip, the reconstruction can be performed by minimising the errors between the five pressure measurements on the probe tip and the predictions of a set of models imposing different locations of the stagnation point. The geometry f the probe is designed and validated by CFD simulations, with the basic objective of enabling the algorithm to reconstruct the flow angles even in case of a pressure data loss. The work describes the initial phases of the system development, from the conceptual phase, up to the manufacturing of a first prototype used for the wind tunnel tests
Scattering da N cilindri conduttori sepolti in un semispazio dielettrico: un metodo spettrale
No full textA spectral-domain solution for the scattering problem of a circular cylinder buried in a dielectric half-space
No full textA spectral-domain solution is employed to completely
characterize the two-dimensional electromagnetic plane-wave scattering
problem by a perfectly conducting circular cylinder buried in a
dielectric half-space. Use is made of the plane-wave spectrum to consider
the diffraction, reflection and transmission of cylindrical waves.
Suitable adaptive integration techniques are employed to numerically
solve the spectral integrals. The method is valid for any value of the
cylinder radius, and of the distance between the cylinder and the interface.
Numerical results are presented for both near- and far-field
cases and for both TM and TE polarizations, and a comparison with
other results in the literature is discussed
Fractal two-dimensional Electromagnetic Band-Gap structures
No full textFractal two-dimensional electromagnetic bandgap
(EBG) materials are proposed and studied by means of a full-wave
method developed for diffraction gratings. Such technique allows
us to characterize, in an accurate and rapidly convergent way,
the transmission and reflection properties of periodic fractal
structures with an arbitrary geometry in the unit cell. Both
polarization cases can be treated. A validation of the employed
method is performed through a comparison with theoretical
results and experimental data taken from the literature; the
convergence properties of our method when applied to fractal
EBG materials are checked. In particular, three different fractal
EBGs are considered here. Numerical results are reported for
the transmission efficiency as a function of the frequency and the
incidence angle. Typical effects due to the fractal geometry are
observed, like multiband behavior and enlargement of stopbands
Full-wave Analysis of Dielectric EBG Materials: Fractal Structures and Defect Characterization
No full textFEMMINISMI, VIOLENZA E RICERCA STORICA
No full textIl saggio esplora in una prospettiva storica il rapporto tra femminismi e violenza, discutendo al contempo come la ricerca storica si sia occupata del tema negli ultimi quarant'anni
Generalized plane-wave expansion of cylindrical functions in lossy media convergent in the whole complex plane
No full textElectromagnetic scattering by buried objects may involve a plane-wave expansion of the related fields, which depends on the objects' geometry. Furthermore, involved media in realistic cases are lossy, which requires the analytic continuation of formulae known for the lossless cases, due to the complex nature of the wave vectors. This problem has been covered in a previous paper, but the expression found still does not converge in some areas of space. In this paper, a new, convergent, expression of the spectrum of cylindrical functions in lossy media is analytically computed and its convergence limits are discussed. (C) 2011 Elsevier B.V. All rights reserved
Periodic defects in 3D Electromagnetic Band-Gap media
No full textIn this paper a full-wave technique is employed to characterize 3D-EBGs with periodic defects. The metod reveals to be versatile and to have good convergence properties. An example of practical application is provided, concerning a woodpile-resonator microstrip antenna
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