Search results for "Phase"

Hidden Oscillations In The Closed-Loop Aircraft-Pilot System And Their Prevention

2016

The paper is devoted to studying and prevention of a special kind of oscillations-the Pilot Involved Oscillations (PIOs) which may appear in man-machine closed-loop dynamical systems. The PIO of categories II and III are defined as essentially non-linear unintended steady fluctuations of the piloted aircraft, generated due to pilot efforts to control the aircraft with a high precision. The main non-linear factor leading to the PIO is, generally, rate limitations of the aircraft control surfaces, resulting in a delay in the response of the aircraft to pilot commands. In many cases, these oscillations indicate presence of hidden, rather than self-excited attractors in the aircraft-pilot state…

Unraveling the nature of universal dynamics in O(N) theories

2020

Many-body quantum systems far from equilibrium can exhibit universal scaling dynamics which defy standard classification schemes. Here, we disentangle the dominant excitations in the universal dynamics of highly occupied N-component scalar systems using unequal-time correlators. While previous equal-time studies have conjectured the infrared properties to be universal for all N, we clearly identify for the first time two fundamentally different phenomena relevant at different N. We find all N >= 3 to be indeed dominated by the same Lorentzian "large-N" peak, whereas N = 1 is characterized instead by a non-Lorentzian peak with different properties, and for N = 2, we see a mixture of two cont…

On the high-pressure phase stability and elastic properties ofβ-titanium alloys

2017

We have studied the compressibility and stability of different β-titanium alloys at high pressure, including binary Ti–Mo, Ti–24Nb–4Zr–8Sn (Ti2448) and Ti–36Nb–2Ta–0.3O (gum metal). We observed stability of the β phase in these alloys to 40 GPa, well into the ω phase region in the P–T diagram of pure titanium. Gum metal was pressurised above 70 GPa and forms a phase with a crystal structure similar to the η phase of pure Ti. The bulk moduli determined for the different alloys range from 97  ±  3 GPa (Ti2448) to 124  ±  6 GPa (Ti–16.8Mo–0.13O).

Characterization of the pressure induced Ringwoodite to Mg-perovskite+Mg-wuestite phase transition by Catastrophe Theory

2010

A first-order phase transition for pulsar surface

2012

In this paper, we explain the existence of a possible first-order phase transition that may occur over the external solid crust of a pulsar, by means of an interpretation of a particular formal model (drawn from Theoretical Astrophysics) whose thermodynamical phenomenology shows a possible first-order phase transition (according to Landau’s Phenomenological Theory).

Preparation, crystal structure at 298 and 90 K and phase transition in (C2H5NH3) 2[SbBr5] studied by the single crystal X-Ray diffraction method

2004

The reaction of antimony(III) oxide with ethylamine, in molar ratios from 1:1 to 1:10, in concentrated hydrobromic acid leads to the formation of one product – bis(ethylammonium) pentabromoantimonate(III). The structure of (C2H5NH3)2[SbBr5] was determined at 298 and 90 K, below and above the phase transition that occurs at about 158.5 K. The orthorhombic system was found in both phases, space groups Cmca and Pbca at 298 and 90 K, respectively. At both temperatures the structure consists of [SbBr6] 3− octahedra connected via cis bromine atoms forming one-dimensional zig-zag [{SbBr5}2−]n chains. The ethylammonium cations fill the space between polyanionic chains. The organic and inorganic sub…

Can Oscillatory Alpha-Gamma Phase-Amplitude Coupling be Used to Understand and Enhance TMS Effects?

2019

Recent applications of simultaneous scalp electroencephalography (EEG) and transcranial magnetic stimulation (TMS) suggest that adapting stimulation to underlying brain states may enhance neuroplastic effects of TMS. It is often assumed that longer-lasting effects of TMS on brain function may be mediated by phasic interactions between TMS pulses and endogenous cortical oscillatory dynamics. The mechanisms by which TMS exerts its neuromodulatory effects, however, remain unknown. Here, we discuss evidence concerning the functional effects on synaptic plasticity of oscillatory cross-frequency coupling in cortical networks as a potential framework for understanding the neuromodulatory effects o…

Proposta di un framework per la progettazione didattica a scuola

2021

Il presente lavoro di ricerca ha inteso verificare la validità di una struttura predefinita per la stesura di un progetto didattico, precisamente quella fornita agli studenti durante il tirocinio. La progettazione è un fattore chiave nella mediazione tra insegnamento e apprendimento a scuola; le sue fasi investono sia il piano gestionale sia quello delle finalità generali, fino a quello dell’agire in classe e della valutazione. Nel tirocinio 684 futuri insegnanti di scuola dell’infanzia e primaria, frequentanti il corso di laurea in Scienze della Formazione Primaria di Palermo negli anni 2016-2020, hanno utilizzato un frame di progettazione e valutazione didattica; esso è stato costruito te…

The Grain Boundary Wetting Phenomena in the Ti‐Containing  High‐Entropy Alloys: A Review

2021

This review is written during the preparation of M‐era.Net full proposal  ʺGrain boundaries in multicomponent alloys without principal componentʺ (A.K., A.K., G.A.L.  and E.R., application No. 9345). The Institute of Solid State Physics, University of Latvia, as a cen‐ ter of excellence, has received funding from the European Union’s Horizon 2020 Framework Pro‐ gramme H2020‐WIDESPREAD‐01‐2016‐2017‐TeamingPhase2 under grant agreement no. 739508,  project CAMART2. 

Study of scintillation light collection, production and propagation in a 4 tonne dual-phase LArTPC

2020

The $3 \times 1 \times 1$ m$^3$ demonstrator is a dual phase liquid argon time projection chamber that has recorded cosmic rays events in 2017 at CERN. The light signal in these detectors is crucial to provide precise timing capabilities. The performances of the photon detection system, composed of five PMTs, are discussed. The collected scintillation and electroluminescence light created by passing particles has been studied in various detector conditions. In particular, the scintillation light production and propagation processes have been analyzed and compared to simulations, improving the understanding of some liquid argon properties.