Microcanonical equilibrium properties of chiral liquid crystals—a Monte Carlo study

Chiral liquid crystals have been investigated by means of a multicanonical Monte Carlo approach in order to characterize their phase behaviour by microcanonical equilibrium properties. The liquid crystals were described by three-dimensional lattice systems with intermolecular interactions given by the chiral Lebwohl-Lasher potential. Self-determined boundary conditions have been applied in order to enable the formation of chiral phases with equilibrium pitch. Selected thermodynamic properties, e.g. microcanonical entropy, temperature, heat capacity and a set of order parameters have been determined with dependence on microcanonical total energy. A cholesteric phase with temperature-induced helix inversion could be proven where the helical superstructure of the single component system studied changed its handedness through an infinite-pitch system. The thermodynamical behaviour in the microcanonical ensemble was found to be very similar to the behaviour in the canonical ensemble. The study of microcanonical equilibrium properties by means of multicanonical Monte Carlo simulations was shown to be a powerful tool for the study of the phase behaviour of model liquid crystals.     

WEIGHT-CONTROLLED RECRUITMENT OF THE ANCHOVY IN THE LATE LARVAL STAGE

ABSTRACT. A formula for the rate of recruitment of the anchovy in the late larval stage is proposed. Recruitment is assumed to occur when the weight crosses a threshold value. The study is undertaken in the framework of a model of fish dynamics which is presented in the first part of the paper.     

THE ENERGY MOBILITY

The energy mobility method is presented and applied both numerically and experimentally to thin plates of high modal density. The energy mobility is defined as the ratio of the frequency averaged quadratic velocity at one point of a structure to the frequency averaged active power injected at one point of the structure. It can be calculated using only classic input and transfer mobilities. The property of energy additivity of the contributions of several external loads is shown to be a good approximation in the case of a single structure. To quantify the approximations on typical structures one is interested in, numerical simulations are presented on plates. A good agreement is found between the predictions using the energy mobility and the exact calculations. An experiment conducted on a plate with a real excitation confirms that the prediction of the energy mobility approach can be quite satisfactory. Finally, a remarkable property for the energy mobility (contrary to standard mobility) is noted: the insensitivity to the presence of a mass heterogeneity at driving points. This property allows one to simplify considerably the characterization of industrial structures that have in general a lot of heterogeneities. The energy mobility concept is further applied to the vibrational behaviour of an assembly. For each subsystem the connection is described by adding injected power and coupling power into the energy additivity. The equality of the frequency averaged quadratic velocity and the power flow balance at each coupling point allows one to calculate the coupling power at connection points with energy mobilities of uncoupled subsystems. A system of two plates has been used to compare the energy mobility calculation and the exact one given by the classic mobility method. The comparison shows that a connectivity factor must be introduced to keep the same formalism generally used with classic mobilities. A generalized definition for the energy mobility is then established.