Search results for " Linear"
showing 10 items of 643 documents
Active disturbance rejection control of linear induction motor
2017
This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input-output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodelling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, t…
Positron production using a 9 MeV electron linac for the GBAR experiment
2020
For the GBAR (Gravitational Behaviour of Antihydrogen at Rest) experiment at CERN's Antiproton Decelerator (AD) facility we have constructed a source of slow positrons, which uses a low-energy electron linear accelerator (linac). The driver linac produces electrons of 9 MeV kinetic energy that create positrons from bremsstrahlung-induced pair production. Staying below 10 MeV ensures no persistent radioactive activation in the target zone and that the radiation level outside the biological shield is safe for public access. An annealed tungsten-mesh assembly placed directly behind the target acts as a positron moderator. The system produces $5\times10^7$ slow positrons per second, a performan…
Variazioni di carbonio organico nei suoli italiani dal 1979 al 2008
2010
I suoli contengono circa tre volte la quantità di carbonio disponibile a livello mondiale nella vegetazione e circa il doppio di quella presente in atmosfera. Tuttavia il carbonio organico del suolo (SOC) si è ridotto in molte aree, mentre è stato rilevato un aumento della CO2 atmosferica. Ricerche recenti hanno dimostrato che sono stati i cambiamenti di uso e gestione del suolo a provocare le maggiori perdite di SOC nel recente passato, piuttosto che le più alte temperature e i cambiamenti delle precipitazioni conseguenti il cambiamento climatico. Lo scopo principale di questo lavoro è quello di stimare le variazioni del contenuto di carbonio organico dei suoli (carbon stock, CS) in Italia…
Modelling the relationship between sexual reproduction and rhizome growth in Posidonia oceanica (L.) Delile
2006
The relationship between flowering and growth performance of Posidonia oceanica (L.) Delile in meadows distributed along the south-eastern coast of Sicily (Italy) was investigated by means of a statistical model (generalized linear mixed model) combined with the lepidochronological analysis. Over a 28-year period, 67 floral stalk remains were observed. The highest flowering index was recorded in lepidochronological year 1998 (10.1%) and the Inflorescence Frequency per age showed a clear decrease corresponding to 15-year-old shoots. The sexual reproductive event had positive effects on rhizome elongation (cm year−1) and leaf production (no. leaves year−1) in the same flowering year, whilst n…
Adsorption of anionic dyes onto natural, thermally and chemically modified smectite clays
2014
Abstract The aim of this study was to determine the adsorption capacity of the smectite clays (from the overburden of the lignite deposit in Belchatow) for two anionic dyes, i.e. Reactive Blue 81 (RB-81) and Direct Blue 74 (DB-74). Additionally, the influence of the thermal and chemical (acid and alkali) clay modifications on the amount of bonded dyes was investigated. The adsorption capacity of the clay (natural and modified) was different for studied dyes and depended on the initial concentration and modification type. All the modified clays adsorbed the dyes at pH>pHPZC as the negatively charged surfaces of their particles (in accordance with the formula: AOH ↔ AO- + H+) prevented the…
Autorreflexión pedagógica
2019
The autobiographical reflection on school learning makes it possible to explain how personal life guidelines are loading teaching activity with experiences. Educational time does not consist only of a linear narration, but works as the evocation of temporal and spatial memories of an explanation of the present. Personal life is intertwined with school reflection to give meaning to what we decide from teaching
Location of solutions for quasi-linear elliptic equations with general gradient dependence
2017
Existence and location of solutions to a Dirichlet problem driven by $(p,q)$-Laplacian and containing a (convection) term fully depending on the solution and its gradient are established through the method of subsolution-supersolution. Here we substantially improve the growth condition used in preceding works. The abstract theorem is applied to get a new result for existence of positive solutions with a priori estimates.
Feedback Linearization Based Nonlinear Control of SynRM Drives Accounting for Self- and Cross-Saturation
2022
This article proposes a nonlinear controller based on feedback linearization (FL) for synchronous reluctance motor (SynRM) drives which takes into consideration the magnetic saturation. The proposed nonlinear FL control based control technique has been developed starting from the theoretical definition of an original dynamic model of the SynRM taking into consideration both the self- and the cross-saturation effects. Such a control technique permits the dynamics of both the speed and axis flux loops to be maintained constant independently from the load and the saturation of the iron core in both constant flux and variable direct axis flux operating conditions. Finally, sensitivity of the pe…
The use of cryptograms with arithmetic operations in school teaching
2013
The text presents a method of solving cryptograms with arithmetic operations. This method is based on systems of equations. In the case of cryptograms with adding and subtracting operations we have to solve systems of linear equations while in the case of cryptograms with multiplying and dividing operations we have to solve systems of non-linear equations. The method of deciphering cryptograms will be illustrated by examples.
FRAME MODELIZATION OF DISCOURSE PRESSURES ON INFORMATION TRANSFER AND TEXTUAL ORGANIZATION OF A TEXT GENRE.
2023
The present article aims at investigating the discursive pressures at the phrasal and textual level for a text genre, here wine advertisements from Austrian supermarket leaflets. After having developed the theoretical framework of Germanic inspiration, a case study is conducted to highlight these discursive pressures.