1,688 research outputs found
EDUARDO RESCIGNO, Dizionario belliniano, Palermo, L’Epos, 2009 (Harmonia mundi, 6), 550 pp.
Recensione di EDUARDO RESCIGNO, Dizionario belliniano, Palermo, L\u2019Epos, 2009 (Harmonia mundi, 6)
Europa riconosciuta : opera di Verazi e Salieri: una rivisitazione moderna del mito antico
Con Europa riconosciuta, dramma per musica di Mattia Verazi e Antonio Salieri, veniva inaugurato il 3 agosto 1778 il Teatro alla Scala di Milano. La rivisitazione del mito di Europa, simbolo della concordia di popoli e nazioni, dava origine a un\u2019opera nella quale ai vistosi effetti spettacolari si sommava una drammaturgia basata su forti contrasti, rapido avvicendamento delle scene, forme musicali brevi e variate. Influenzata dall\u2019opera gluckiana riformata, Europa riconosciuta si allineava ai pi\uf9 recenti orientamenti del teatro musicale internazionale. With Europa riconosciuta, a Mattia Verazi\u2019s and Antonio Salieri\u2019s \uabdramma per musica\ubb, was inaugurated on the 3rd August 1778 the Teatro alla Scala in Milan. The retelling of the myth of Europe, a symbol of the harmony of peoples and nations, has led to an opera that combined extraordinary spectacular effects with a dramaturgy based on strong contrasts, a rapid alternation of the scenes, short and varied musical forms. Europa riconosciuta was under the influence of Gluck\u2019s reformed opera and followed the most recent orientations of the international musical theatre
Adaptive Polynomial Harmonic Distortion Compensation in Current and Voltage Transformers Through Iteratively Updated QR Factorization
Measuring current and voltage harmonics has paramount importance for improving the power quality of distribution grids. However, the achieved accuracy strongly depends on the adopted instrument transformer (IT). This article proposes an adaptive technique that enables an effective compensation of both the filtering behavior and the harmonic distortion (HD) introduced by current and voltage transformers (VTs), namely the strongest nonlinear effect at low-order harmonics. The approach is based on a flexible, linear in the parameters polynomial modeling of HD in the frequency domain. Model complexity can be different from one harmonic to the other, and it is selected through an automatic iterative process to suit the nonlinear behavior at each specific harmonic order, while avoiding overfitting. In particular, the number of parameters is increased by progressively updating the QR factorization of the regressor matrix trough Householder reflections until a convergence condition is reached. Experimental tests performed on an inductive VT and current transformer (CT) highlight the effectiveness of the approach
Slip-rates of blind thrusts in slow deforming areas: examples from the Po Plain (Italy)
We calculate Plio-Pleistocene slip rates on the blind thrusts of the outer Northern Apennines fronts,
that are the potential sources of highly damaging earthquakes, as shown by the MW 6.1-6.0, 2012
Emilia-Romagna seismic sequence. Slip rates are a key parameter for understanding the
seismogenic potential of active fault systems and assessing the seismic hazard they pose, however,
they are difficult to calculate in slow deforming areas like the Po Plain where faulting and folding is
mostly blind. To overcome this, we developed a workflow which included the preparation of a
homogeneous regional dataset of geological and geophysical subsurface information, rich in Plio-
Pleistocene data. We then constructed 3D geological models around selected individual structures
to decompact the clastic units and restore the slip on the fault planes. The back-stripping of the
differential compaction eliminates unwanted overestimation of the slip rates due to compactioninduced
differential subsidence. Finally, to restore the displacement we used different methods
according to the deformation style, i.e. Fault Parallel Flow for faulted horizons, trishear and elastic
dislocation modeling for fault-propagation folds. The result of our study is the compilation of a slip
rate database integrating former published values with 28 new values covering a time interval from
the Pliocene to the present. It contains data on 14 individual blind thrusts including the Mirandola
thrust, seismogenic source of the 29 May 2012, MW 6.0 earthquake. Our study highlights that the
investigated thrusts were active with rates ranging between 0.1-1.0 mm/yr during the last 1.81 Myr.
The Mirandola thrust slipped at 0.86±0.38 mm/yr during the last 0.4 Myr. These rates calculated
with an homogeneous methodology through the entire Po Plain can be charged entirely to the thrust
activity and not to secondary effects like the differential compaction of sediments across the
structures
On Strong Convergence to Equilibrium for the Boltzmann Equation with Soft Potentials
The paper concerns - convergence to equilibrium for weak solutions of
the spatially homogeneous Boltzmann Equation for soft potentials (-4\le
\gm<0), with and without angular cutoff. We prove the time-averaged
-convergence to equilibrium for all weak solutions whose initial data have
finite entropy and finite moments up to order greater than 2+|\gm|. For the
usual -convergence we prove that the convergence rate can be controlled
from below by the initial energy tails, and hence, for initial data with long
energy tails, the convergence can be arbitrarily slow. We also show that under
the integrable angular cutoff on the collision kernel with -1\le \gm<0, there
are algebraic upper and lower bounds on the rate of -convergence to
equilibrium. Our methods of proof are based on entropy inequalities and moment
estimates.Comment: This version contains a strengthened theorem 3, on rate of
convergence, considerably relaxing the hypotheses on the initial data, and
introducing a new method for avoiding use of poitwise lower bounds in
applications of entropy production to convergence problem
Frequency-domain nonlinear modeling approaches for power systems components - A comparison
Harmonic simulations play a key role in studying and predicting the impact of nonlinear devices on the power quality level of distribution grids. A frequency-domain approach allows higher computational efficiency, which has key importance as long as complex networks have to be studied. However, this requires proper frequency-domain behavioral models able to represent the nonlinear voltage-current relationship characterizing these devices. The Frequency Transfer Matrix (FTM) method is one of the most widespread frequency domain modeling approaches for power system applications. However, others suitable techniques have been developed in the last years, in particular the X-parameters approach, which comes from radiofrequency and microwave applications, and the simplified Volterra models under quasi-sinusoidal conditions, that have been specifically tailored for power system devices. In this paper FTM, X-parameters and simplified Volterra approaches are compared in representing the nonlinear voltage-current relationship of a bridge rectifier feeding an ohmic-capacitive dc load. Results show that the X-parameters model reaches good accuracy, which is slightly better than that achieved by the FTM and simplified Volterra models, but with a considerably larger set of coefficients. Simplified Volterra models under quasi-sinusoidal conditions allows an effective trade-off between accuracy and complexity
The dissipative linear Boltzmann equation for hard spheres
We prove the existence and uniqueness of an equilibrium state with unit mass
to the dissipative linear Boltzmann equation with hard--spheres collision
kernel describing inelastic interactions of a gas particles with a fixed
background. The equilibrium state is a universal Maxwellian distribution
function with the same velocity as field particles and with a non--zero
temperature lower than the background one, which depends on the details of the
binary collision. Thanks to the H--theorem we then prove strong convergence of
the solution to the Boltzmann equation towards the equilibrium.Comment: 17 pages, submitted to Journal of Statistical Physic
Self-similarity and power-like tails in nonconservative kinetic models
In this paper, we discuss the large--time behavior of solution of a simple
kinetic model of Boltzmann--Maxwell type, such that the temperature is time
decreasing and/or time increasing. We show that, under the combined effects of
the nonlinearity and of the time--monotonicity of the temperature, the kinetic
model has non trivial quasi-stationary states with power law tails. In order to
do this we consider a suitable asymptotic limit of the model yielding a
Fokker-Planck equation for the distribution. The same idea is applied to
investigate the large-time behavior of an elementary kinetic model of economy
involving both exchanges between agents and increasing and/or decreasing of the
mean wealth. In this last case, the large-time behavior of the solution shows a
Pareto power law tail. Numerical results confirm the previous analysis
Distributional and classical solutions to the Cauchy Boltzmann problem for soft potentials with integrable angular cross section
This paper focuses on the study of existence and uniqueness of distributional
and classical solutions to the Cauchy Boltzmann problem for the soft potential
case assuming integrability of the angular part of the collision
kernel (Grad cut-off assumption). For this purpose we revisit the
Kaniel--Shinbrot iteration technique to present an elementary proof of
existence and uniqueness results that includes large data near a local
Maxwellian regime with possibly infinite initial mass. We study the propagation
of regularity using a recent estimate for the positive collision operator given
in [3], by E. Carneiro and the authors, that permits to study such propagation
without additional conditions on the collision kernel. Finally, an
-stability result (with ) is presented assuming the
aforementioned condition.Comment: 19 page
A Low-Cost Approach to the Skin Effect Compensation in Cylindrical Shunts
In this paper the development of a new design solution for high-current shunt resistors is presented, which allows achieving very good accuracy while requiring a simple and low-cost manufacturing process. It is based on a solid cylinder having the voltage measurement circuit which runs through two holes drilled in the cylinder itself. Starting from the well-known expression of the current density in a cylindrical conductor, the frequency response of the shunt is obtained in closed form as a function of the geometric parameters. In turn, the positions of the voltage measurement terminals are chosen by optimizing the frequency response function over a specified range. A shunt prototype has been manufactured and its measurement performance has been evaluated. The experimental results confirm the validity of the approach and highlight the significant improvement with respect to the single-hole cylindrical shunt which has been recently proposed by the authors. The obtained measurement accuracy is noticeable when compared with the ease of manufacturing
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