Search results for "tractor"
showing 9 items of 219 documents
Polarisation attraction and incoherent modulation instability in optical fibers
2006
This thesis, entitled « Polarisation attraction and incoherent modulation instability in optical fibers », presents a theoretical and experimental study of two new processes from the nonlinear optic in optical fibers domain. We introduce in the first chapter some theoretical notions useful for the comprehension of this work. Then, we demonstrate in the second chapter that it is possible to generate some modulation instability in optical fibers using a partially coherent optical beam. We highlight and observe the main properties of the phenomenon. We study the polarisation attraction in isotropic fibers process in the third chapter. Our work proves the existence of the phenomenon, and permit…
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…
Highly occupied gauge theories in 2 + 1 dimensions : a self-similar attractor
2019
Motivated by the boost-invariant Glasma state in the initial stages in heavy-ion collisions, we perform classical-statistical simulations of SU(2) gauge theory in 2+1 dimensional space-time both with and without a scalar field in the adjoint representation. We show that irrespective of the details of the initial condition, the far-from-equilibrium evolution of these highly occupied systems approaches a unique universal attractor at high momenta that is the same for the gauge and scalar sectors. We extract the scaling exponents and the form of the distribution function close to this non-thermal fixed point. We find that the dynamics are governed by an energy cascade to higher momenta with sc…
Feasibility of controlling the thermal regime of the transmission of agricultural machines in conditions of Ukraine
2019
During the heating of the tractor gearbox oil, there is a decrease in the efficiency, which leads to an increase in fuel consumption. This is observed at any time of the year. The efficiency of a gearbox as a function of the ambient temperature and the operating time has been obtained. This allows you to predict the effectiveness of the work of the tractor. Various methods to improve transmission performance were analyzed. The article analyzes the parameters of the exhaust gas of a tractor diesel engine. It was proved that one of the effective methods for temperature control is to use of an exhaust gas heat recovery system. It was shown that the capacity of the exhaust gas recovery system i…
SPSS: Análisis de distractores
2014
Mostra com fer l'analisi de distractors d'una prova. Realizar el análisis de distractores de una prueba estandarizada. It shows how to realise the distractor analysis of a standarized test.
Singular tori as attractors of four-wave-interaction systems
2009
We study the spatiotemporal dynamics of the Hamiltonian four-wave interaction in its counterpropagating configuration. The numerical simulations reveal that, under rather general conditions, the four-wave system exhibits a relaxation process toward a stationary state. Considering the Hamiltonian system associated to the stationary state, we provide a global geometrical view of all the stationary solutions of the system. The analysis reveals that the stationary state converges exponentially toward a pinched torus of the Hamiltonian system in the limit of an infinite nonlinear medium. The singular torus thus plays the role of an attractor for the spatiotemporal wave system. The topological pr…
Coexistence of hidden attractors and multistability in counterexamples to the Kalman conjecture
2019
The Aizerman and Kalman conjectures played an important role in the theory of global stability for control systems and set two directions for its further development – the search and formulation of sufficient stability conditions, as well as the construction of counterexamples for these conjectures. From the computational perspective the latter problem is nontrivial, since the oscillations in counterexamples are hidden, i.e. their basin of attraction does not intersect with a small neighborhood of an equilibrium. Numerical calculation of initial data of such oscillations for their visualization is a challenging problem. Up to now all known counterexamples to the Kalman conjecture were const…
Synchronization of hidden chaotic attractors on the example of radiophysical oscillators
2017
In the present paper we consider the problem of synchronization of hidden and self-excited attractors in the context of application to a system of secure communication. The system of two coupled Chua models was studied. Complete synchronization was observed as for self-excited, as hidden attractors. Beside it for hidden attractors some special type of dynamic was revealed.
Estudio comparativo in vitro de distintos métodos de extracción de tornillos fracturados en implantes
2022
En los tratamientos sobre implantes, pueden aparecer complicaciones como la fractura de los tornillos que sujetan las prótesis que van sobre ellos. El objetivo principal de esta investigación fue evaluar in vitro la efectividad de los sistemas mecánicos de extracción de tornillos fracturados en implanto-prótesis. Material y Método: Se utilizaron 180 muestras que consistían en un implante de conexión interna Sweden&Martina® con un pilar prefabricado de titanio Sweden&Martina®, que se atornillaba al implante con un tornillo de titanio, de la misma casa comercial. Cada una de las muestras fue sometida a una carga cíclica y posteriormente a una carga de compresión hasta conseguir la fractura de…