Effects of oscillatory behavior of the dipole function on the dissociation dynamics of the classical driven Morse oscillator

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Proposal of an alternative transmission line model for symmetrical and asymmetrical configurations

This article shows a transmission line model for simulation of fast and slow transients, applied to symmetrical or asymmetrical configurations. A transmission line model is developed based on lumped elements representation and state-space techniques. The proposed methodology represents a practical procedure to model three-phase transmission lines directly in time domain, without the explicit or implicit use of inverse transforms. In three-phase representation, analysis modal techniques are applied to decouple the phases in their respective propagation modes, using a correction procedure to set a real and constant matrix for untransposed lines with or without vertical symmetry plane. The proposed methodology takes into account the frequency-dependent parameters of the line and in order to include this effect in the state matrices, a fitting procedure is applied. To verify the accuracy of the proposed state-space model in frequency domain, a simple methodology is described based on line distributed parameters and transfer function associated with input/output signals of the lumped parameters representation. In addition, this article proposes the use of a fast and robust integration procedure to solve the state equations, enabling transient and steady-state simulations. The results obtained by the proposed methodology are compared with several established transmission line models in EMTP, taking into account an asymmetrical three-phase transmission line. The principal contribution of the proposed methodology is to handle a steady fundamental signal mixed with fast and slow transients, including impulsive and oscillatory behavior, by a practical procedure applied directly in time domain for symmetrical or asymmetrical representations. (C) 2011 Elsevier Ltd. All rights reserved.

Dynamics of experimental populations of native and introduced blowflies (Diptera: Calliphoridae): mathematical modelling and the transition from asymptotic equilibrium to bounded oscillations

The equilibrium dynamics of native and introduced blowflies is modelled using a density-dependent model of population growth that takes into account important features of the life-history in these flies. A theoretical analysis indicates that the product of maximum fecundity and survival is the primary determinant of the dynamics. Cochliomyia macellaria, a blowfly native to the Americas and the introduced Chrysomya megacephala and Chrysomya putoria, differ in their dynamics in that the first species shows a damping oscillatory behavior leading to a one-point equilibrium, whereas in the last two species population numbers show a two-point limit cycle. Simulations showed that variation in fecundity has a marked effect on the dynamics and indicates the possibility of transitions from one-point equilibrium to bounded oscillations and aperiodic behavior. Variation in survival has much less influence on the dynamics.

On the control of a non-ideal engineering system: A friction-driven oscillating system with limited power supply

In this work a switching feedback controller for stick-slip compensation of a 2-DOF mass-spring-belt system which interacts with an energy source of limited power supply (non-ideal case) is developed. The system presents an oscillatory behavior due to the stick-slip friction. As the system equilibrium for a conventional feedback controller is not the origin, a switching control law combining a state feedback term and a discontinuous term is proposed to regulate the position of the mass. The problem of tracking a desired periodic trajectory is also considered. The feedback system is robust with respect to the friction force that is assumed to be within known upper and lower bounds.

Oscilador harmônico amortecido e séries infinitas

Neste trabalho discute-se um arranjo experimental bastante simples e de baixo custo, cujo objetivo consiste em se exemplificar de forma concreta a aplicação de técnicas matemáticas envolvendo solução por séries infinitas destinadas ao estudo de determinado fenômeno físico. Esta prática desenvolvida e direcionada aos alunos de um curso de Graduação em Matemática, consiste basicamente de um estudo quantitativo relacionado ao comportamento oscilatório amortecido de um sistema constituído por uma massa acoplada a uma mola. Os resultados experimentais corroboraram muito bem a teoria fenomenológica e possibilitam a determinação numérica de uma constante física normalmente considerada desprezível, mencionada de passagem nos livros textos. Um fato de destaque deste trabalho referente ao fenômeno ondulatório estudado, ilimitado no tempo, mas limitado no espaço, é o de permitir uma boa discussão com os estudantes sobre o conceito de limite matemático.

Exact dynamics of single-qubit-gate fidelities under the measurement-based quantum computation scheme

Measurement-based quantum computation is an efficient model to perform universal computation. Nevertheless, theoretical questions have been raised, mainly with respect to realistic noise conditions. In order to shed some light on this issue, we evaluate the exact dynamics of some single-qubit-gate fidelities using the measurement-based quantum computation scheme when the qubits which are used as a resource interact with a common dephasing environment. We report a necessary condition for the fidelity dynamics of a general pure N-qubit state, interacting with this type of error channel, to present an oscillatory behavior, and we show that for the initial canonical cluster state, the fidelity oscillates as a function of time. This state fidelity oscillatory behavior brings significant variations to the values of the computational results of a generic gate acting on that state depending on the instants we choose to apply our set of projective measurements. As we shall see, considering some specific gates that are frequently found in the literature, the fast application of the set of projective measurements does not necessarily imply high gate fidelity, and likewise the slow application thereof does not necessarily imply low gate fidelity. Our condition for the occurrence of the fidelity oscillatory behavior shows that the oscillation presented by the cluster state is due exclusively to its initial geometry. Other states that can be used as resources for measurement-based quantum computation can present the same initial geometrical condition. Therefore, it is very important for the present scheme to know when the fidelity of a particular resource state will oscillate in time and, if this is the case, what are the best times to perform the measurements.

Error estimates for a neumann problem in highly oscillating thin domains

In this work we analyze the convergence of solutions of the Poisson equation with Neumann boundary conditions in a two-dimensional thin domain with highly oscillatory behavior. We consider the case where the height of the domain, amplitude and period of the oscillations are all of the same order, and given by a small parameter e > 0. Using an appropriate corrector approach, we show strong convergence and give error estimates when we replace the original solutions by the first-order expansion through the Multiple-Scale Method.

Análise cinemática da oscilação corporal de idosos com doença de Parkinson: efeitos da restrição visual

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Gráficos de X com esquemas especiais de amostragem para o controle de médias que oscilam ou para o controle de processos que geram observações autocorrelacionadas

Pós-graduação em Engenharia Mecânica - FEG

Ambiente térmico y el bienestar de los cerdos en el período de descanso previo al sacrificio

The research aimed to evaluate the relationship between the thermal environment of the rest pens in a pig slaughterhouse and the surface temperature (ST) of the animals as well as the effect of intermittent water spraying on thermal comfort. There were two visits to slaughter industrial being in each selected three pens of rest, one for control treatment (no spray throughout the period) and two for the treatment of intermittent spraying water (30 minutes intervals with constant spray followed by 30 minutes then turned off). Assessments began at the time of discharging animals in which are taken the thermographic images from lots using an infrared thermographic camera. After housing in the pens, were registered the thermographic images and the respiratory frequency (RF) every five minutes for four hours. Were evaluated the temperature, relative humidity and temperature-humidity index (THI). Considering the values of THI was observed that the animals remained in a condition of comfort only at the time of his arrival at the slaughterhouse. The ST and RF of the animals kept in the pens without sprinkler system (control) showed a linear increase in function of time of day, with increasing temperature. The treatment with intermittent sprinkling of water was observed oscillatory behavior of the ST and RF, however it was always lower than the control treatment, even in times when the water sprinklers were turned off. The time required of spray to reduction and stabilization of the ST of the animals was limited to the combination of temperature and relative humidity, being estimated at 25 minutes at times of higher THI. The maximum environmental temperature during evaluation was 28.4 oC.

Semilinear parabolic problems in thin domains with a highly oscillatory boundary

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Rheological behavior of Peruvian carrot starch gels as affected by temperature and concentration

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)