Walking Wheel

A hypothesis was proposed that during the bipedal walking, there appear stable periodic movements in certain variables (self-oscillations). In this case, it is possible to easily change parameters of this periodic locomotion using open (without feedback) control loops with respect to some of the variables. As the first stage in testing this hypothesis, dynamics of the walking wheel downward movement along an inclined plane was analytically studied. Walking wheel is the simplest model of passive bipedal walking. When it moves, energy is supplied to the system due to the force of gravity action. It is shown that point mapping of the wheel angular speed alteration per step (Poincare map) in the overwhelming majority of cases has one fixed point. This fixed point corresponds either to stable periodic solution (self-oscillation), which is the wheel rolling down an inclined plane, or to the wheel movement ending with its termination as a result of the endless series of impacts with swinging on two legs. In the degenerate case, the Poincare map has two fixed points. One of them corresponds to the unstable limiting cycle matching the wheel rolling, and the second corresponds to a wheel stop. In this case, the limiting cycle is stable outside and unstable inside itself

FACILITATING PEDESTRIANIZATION FOR REDEVELOPMENT OF COMMERCIAL PRECINCTS, CASE STUDY AMINABAD, LUCKNOW

The early stages of urban development people tended to focus on solving the problem of vehicular traffic, so now a large number of existing roadways are occupied by vehicles, triggering disputes and problems about pedestrian safety and comfort. Despite its modernistic and functionalistic origins, the pedestrian street became an important theme for many writers interested in the social life, history, scale and aesthetics of the traditional European towns The territorial strategy of the pedestrian precinct is primarily about demarcating a certain territory for pedestrian use, prohibiting car traffic, and limiting cycle traffic within the area. urban growth with sprawl is completely unpleasant and unwanted and the correct solution is “intermediate cities” to integrate all of the suitable aspects in a city. As you considered, this article discusses about pedestrianization and its benefits. In a city with large growth especially in developing countries, one of the cases that usually are neglected is pedestrianisation and attendance of citizens in urban spaces.

Self-Exciting Wire Transducer for Time-Varying Strain Measurements

The solution of a system exciting wire vibrations of a wire sensor allowing one to perform time-varying measurements, including rapid changes and of a chaotic nature, are presented in this paper. The system is based on the typical two-coil solution, in which one of the coils is responsible for exciting the wire vibrations while the other coil is used for recording those vibrations. The task of maintaining and not fading away the natural vibrations of the wire was solved by the excitation of self-exciting vibrations by the impulse system synchronized using the wire motion velocity. The mathematical analysis of the wire motion in the system with the impulse generator, in which the existence of the limiting cycle of the wire natural frequency was proved, is shown in this paper. The computer simulation results, illustrating the metrological possibilities of the solution as well as an example of a physical implementation, are also presented.

Approach to a Limiting Cycle in Thermally Relaxing Media

The thermally activated dynamics of an uniaxial superparamagnetic particle are studied here from the point of view of approach towards a steady state minor hysteresis loop representing a limiting cycle. The particle is initially at an arbitrary state, and is driven by a sufficiently small external applied ac magnetic field till the limiting minor hysteresis loop is reached with a desired precision. The number of periods required to reach the limiting cycle is found to satisfy an Arrhenius-type law, with an exponential dependence on the inverse ambient temperature. We tentatively associate this result with energy dissipation, its origin, however, remains quite unclear.

Nonlinear Model of River Runoff Fluctuations with Chaotic Regimes

It is shown, that a loss of stability and a birth of a limiting cycle come into existence when only two variables (water resources, runoff) and the equations in the simplest form are exploited. Speed of evaporation is chosen as a managing parameter. Upon the influence of external force and the certain interval of values of the evaporation speed in the system chaotic regimes are established. The opportunity of occurrence of chaotic regimes in fluctuations of some concrete rivers is confirmed by values of the chaos diagnostic characteristics designed for them.

Friction-Induced Vibrations: From Linear Stability Criteria to Non-Linear Analysis of Limiting Cycles

The contact of two elastic bodies with a frictional interface can lead to friction-induced instabilities. The instabilities are either due to the velocity-dependence of friction, or due to the coupling of friction with the thermal expansion or wear, or due to the destabilization of the interface elastic waves. The instabilities lead to friction-induced vibrations. The linear elasticity usually provides a criterion for the onset of the instability and predicts that the amplitude of the unstable vibration grows exponentially with time. However, it does not provide any information about the amplitudes of vibrations. It is expected that the amplitudes of vibrations grow exponentially until they leave the range of applicability of the linear theory and reach a certain limiting cycle. We discuss how various non-linear methods of pattern-formation analysis can be applied to this problem, including the Turing systems, self-organized criticality, etc.