Search results for "armo"
showing 10 items of 1364 documents
Isotropic p-harmonic systems in 2D Jacobian estimates and univalent solutions
2016
The core result of this paper is an inequality (rather tricky) for the Jacobian determinant of solutions of nonlinear elliptic systems in the plane. The model case is the isotropic (rotationally invariant) p-harmonic system ...
“Things which don’t shift and grow are dead things”: Revisiting Betonie’s Waste-Lands in Leslie Silko’s Ceremony
2014
This article explores the socio-political background that led to widespread Native American urban relocation in the period following World War II – a historical episode which is featured in Leslie Marmon Silko’s acclaimed novel Ceremony (1977). Through an analysis of the recycling, reinterpreting practices carried out by one of Ceremony’s memorable supporting characters, Navajo healer Betonie, Silko’s political aim to interrogate the state of things and to re-value Native traditions in a context of ongoing relations of coloniality is made most clear. In Silko’s novel, Betonie acts as an organic intellectual who is able to identify and challenge the 1950s neocolonial structure that forced Na…
Phylogenetic generic classification of parmelioid lichens (Parmeliaceae, Ascomycota) based on molecular, morphological and chemical evidence
2010
WOS: 000285566000008
The Harmonization of Academic Calendars in Europe : A Present View of Old Questions at Stake
1996
International audience
L'harmonisation des calendriers universitaires en Europe : une permanence des enjeux
1997
International audience
Simulation of a single-phase five-level cascaded H-Bridge inverter with multicarrier SPWM B-Spline based modulation techniques
2017
Multilevel Power Inverters are now often used to convert DC to AC voltage waveform. This kind of converter allows high power quality with low output harmonics and lower commutation losses with respect to the traditional ones in order to optimize this aspect. This paper presents a novel simulation analysis of the Multicarrier Sinusoidal Pulse Width Modulation (MC SPWM) techniques B-Spline functions based to control the switches of five-level single-phase cascaded H-bridge inverter. In order to verify the performance of the converter, the harmonic content of the voltage due to modulation techniques has been taken into account. Results highlight the comparison between different B-Spline functi…
New approach for harmonic mitigation in single-phase five-level CHBMI with fundamental frequency switching
2017
The main objective of this paper is to study and analyse the voltage output waveform of a multilevel inverter, to suggest a new approach for harmonic mitigation improving the converter performance. These last type of converters represent a new technology in the field of DC/AC electrical energy conversion, presenting advantages respect to the traditional converters. In fact, the multilevel power converters present a low harmonic content and a high voltage level. The paper considers a five-level single-phase cascaded H-bridge inverter and fundamental frequency modulation techniques. The voltage waveform analysis has allowed to identify a working area of the converter where there are lowest va…
A set of indicators for arc faults detection based on low frequency harmonic analysis
2016
In this paper a novel set of indicators is presented for arc faults detection in electrical circuits. The indicators are defined starting from an experimental characterization of the arc fault phenomenon and the study of the arcing current in several test conditions, which were chosen in accordance with the UL 1699 Standard requirements. The proposed parameters are measured by means of a high resolution low frequency spectral analysis of the arcing current, which allows to achieve a good spectral resolution even with short observation windows.
Experimental analysis with FPGA controller-based of MC PWM techniques for three-phase five level cascaded H-bridge for PV applications
2016
The FPGA represents a valid solution for the design of control systems for inverters adopted in the field of PV systems because of their high flexibility of use. This paper presents an experimental analysis of the MC SPWM techniques for a three-phase, five-level, cascaded H-Bridge inverter with FPGA controller-based. Several control algorithms are implemented by means of the VHDL programming language and the output voltage waveforms obtained from the main PWM techniques are compared in terms of THD%. Simulation and experimental results are analysed, compared and discussed.
A CONTROL LAW FOR ROBOTIC MANIPULATORS BASED ON A FILTERED SIGNAL TO GENERATE PD ACTION AND VELOCITY ESTIMATES
2007
This paper deals with an adaptive control law for robotic manipulators based on a filtered signal to generate both the PD action and velocity estimates of the joints, suitable for trajectory tracking tasks, with the particular aim of reducing the harmonic content of the mechanical torques developed at the joints and thus avoiding excitation of unmodelled dynamics and instability. The practical aspects relative to the implementation of the control law are considered as relevant and, consequently, are detailed. In particular, several methods suitable to compute velocity estimates are discussed and compared with the method described in the paper. All of the above methods are illustrated by mea…