Richard E. Eykholt

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We investigate rhythmic finger tapping in both the presence and the absence of a metronome. We examine both the time intervals between taps and the time lags between the stimulus tones from the metronome and the response taps by the subject. We analyze the correlations in these data sets, and we search for evidence of deterministic chaos, as opposed to(More)
Considering linearized motion about a resting basic state, we derive analytical solutions of the equatorial β-plane primitive equations under the assumption that the flow is steady in a reference frame moving eastward with a diabatic forcing resembling a Madden-Julian oscillation (MJO) convective envelope. The spectral series solutions allow us to decompose(More)
We use the Hestenes-Dirac (space-time algebra) and Lanczos-Dirac (biquaternion) equations to analyze the phases of a Dirac spinor. The biquaternionic treatment implies that the β parameter in Hestenes' formalism is related to the spinor's phases. We then identify two possible formula sets to replace Hestenes' definitions of the phases. By identifying the(More)
SIMPLE ANALYTICAL SOLUTIONS FOR POTENTIAL VORTICITY INTRUSIONS Using potential temperature (θ) as the vertical coordinate, we derive analytical solutions of the potential vorticity (PV) invertibility principle for the case in which the flow is y-independent and an isolated PV anomaly is confined within an ellipse in the (x, θ)-plane. The solutions aid in(More)
Despite the continuous growth of the available computational power, it is undoubtedly beneficial, for both the research and operational communities, to increase the efficiency of Numerical Weather Prediction. Because parameterizations often occupy a significant portion of the total execution time the first focus of this work is to provide a methodology to(More)
This Letter reports the first experimental demonstration of chaotic excitations through modulational instability for waves with a repulsive nonlinearity. The experiments were carried out for surface spin waves in a magnetic thin film strip in an active feedback ring configuration. At a low ring gain level, one observes the self-generation of one eigenmode.(More)
This Letter reports experimental results on the three-wave interactions of backward volume spin waves in a magnetic film and the excitation of chaotic waves through such interactions in a magnetic film-based active feedback ring. The three-wave interactions manifest themselves in the power saturation responses of spin waves, and the chaotic excitation(More)
Chaotic spin-wave solitons in magnetic film active feedback rings were observed for the first time. At some ring gain level, one observes the self-generation of a single spin-wave soliton pulse in the ring. When the pulse circulates in the ring, its amplitude varies chaotically with time. Numerical simulations based on a gain-loss nonlinear Schrödinger(More)
The amplification of supercritical waves in steep channels is examined analytically using a one-dimensional dynamic solution of the Saint-Venant equations. Existing methods were modified to describe the amplification of surface waves over a normalized channel length rather than over a single wavelength. The results are strikingly different, and a(More)
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