T. Molteno - Academia.edu (original) (raw)
Papers by T. Molteno
Physical Review E, 1998
We have studied the early time evolution of granular segregation patterns in a horizontal rotatin... more We have studied the early time evolution of granular segregation patterns in a horizontal rotating cylinder partially filled with a sand/salt mixture. The growth of concentration fluctuations starting from premixed initial conditions was analyzed using Fourier techniques. In one mixture, we observed generally merging dynamics in the segregated bands up to the onset of saturation. At the threshold of saturation, we found a spectrum of wavelengths with a broad peak. The peak position was nearly independent of the tube rotation rate.
Physical Review E, 1995
We identify the template organizing the chaotic dynamics of a vibrating string and show how to es... more We identify the template organizing the chaotic dynamics of a vibrating string and show how to estimate topological parameter values directly from an experimental time series. We call these data processing techniques \topological time series analysis." The chaotic motions of a vibrating string are shown to be governed by a dissipative horseshoe map whose periodic orbit spectrum is, at the topological level, well described by a unimodal map of the interval.
Journal of Biophysics, 2009
A quantitative frequency-domain model of induction-based magnetoreception is presented for elasmo... more A quantitative frequency-domain model of induction-based magnetoreception is presented for elasmobranch fishes. We show that orientation with respect to the geomagnetic field can be determined by synchronous detection of electrosensory signals at harmonics of the vestibular frequency. The sensitivity required for this compass-sense mechanism is shown to be less than that known from behavioral experiments. Recent attached-magnet experiments have called into doubt the induction-based mechanism for magnetoreception. We show that the use of attached magnets would interfere with an induction-based mechanism unless relative movement between the electrosensory system and the attached magnet is less than 100 mum. This suggests that further experiments may be required to eliminate induction as a basis for magnetoreception.
OCEANS 2006 - Asia Pacific, 2006
This paper describes our initial investigation of an inertial power generation system, designed f... more This paper describes our initial investigation of an inertial power generation system, designed for use in small, low-power, long-endurance ocean exploration robots. The system recovers small amounts of power from the movements caused by ocean waves. The primary focus of the investigation to date has been the development of efficient power recovery system electronics that extract useful power from a wide range of ocean wave amplitudes and frequencies.
Physical Review Letters, 2000
We describe experiments on Benard-Marangoni convection in horizontal layers of two immiscible liq... more We describe experiments on Benard-Marangoni convection in horizontal layers of two immiscible liquids. Unlike previous experiments, which used gases as the upper fluid, we find a square planform close to onset which undergoes a secondary bifurcation to rolls at higher temperature differences. The scale of the convection pattern is that of the thinner lower fluid layer for which buoyancy and surface tension forces are comparable. The wave number of the pattern near onset agrees with the linear stability prediction for the full two-layer problem. The square planform is in qualitative agreement with recent two-layer weakly nonlinear theories, which fail however to predict the transition to rolls.
Physical Review Letters, 1997
Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, h... more Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in certain mixtures:
Proceedings of the 18th …, 2011
AbstractWe are building a compiler to help map large computations into FPGAs because we are also... more AbstractWe are building a compiler to help map large computations into FPGAs because we are also developing hardware to perform Electrical Impedance Tomography (EIT) in real-time. The EIT inverse problem is non-linear and severely ill-posed and the sampling ...
Physical Review E, 1998
We have studied the early time evolution of granular segregation patterns in a horizontal rotatin... more We have studied the early time evolution of granular segregation patterns in a horizontal rotating cylinder partially filled with a sand/salt mixture. The growth of concentration fluctuations starting from premixed initial conditions was analyzed using Fourier techniques. In one mixture, we observed generally merging dynamics in the segregated bands up to the onset of saturation. At the threshold of saturation, we found a spectrum of wavelengths with a broad peak. The peak position was nearly independent of the tube rotation rate.
Physical Review E, 1995
We identify the template organizing the chaotic dynamics of a vibrating string and show how to es... more We identify the template organizing the chaotic dynamics of a vibrating string and show how to estimate topological parameter values directly from an experimental time series. We call these data processing techniques \topological time series analysis." The chaotic motions of a vibrating string are shown to be governed by a dissipative horseshoe map whose periodic orbit spectrum is, at the topological level, well described by a unimodal map of the interval.
Journal of Biophysics, 2009
A quantitative frequency-domain model of induction-based magnetoreception is presented for elasmo... more A quantitative frequency-domain model of induction-based magnetoreception is presented for elasmobranch fishes. We show that orientation with respect to the geomagnetic field can be determined by synchronous detection of electrosensory signals at harmonics of the vestibular frequency. The sensitivity required for this compass-sense mechanism is shown to be less than that known from behavioral experiments. Recent attached-magnet experiments have called into doubt the induction-based mechanism for magnetoreception. We show that the use of attached magnets would interfere with an induction-based mechanism unless relative movement between the electrosensory system and the attached magnet is less than 100 mum. This suggests that further experiments may be required to eliminate induction as a basis for magnetoreception.
OCEANS 2006 - Asia Pacific, 2006
This paper describes our initial investigation of an inertial power generation system, designed f... more This paper describes our initial investigation of an inertial power generation system, designed for use in small, low-power, long-endurance ocean exploration robots. The system recovers small amounts of power from the movements caused by ocean waves. The primary focus of the investigation to date has been the development of efficient power recovery system electronics that extract useful power from a wide range of ocean wave amplitudes and frequencies.
Physical Review Letters, 2000
We describe experiments on Benard-Marangoni convection in horizontal layers of two immiscible liq... more We describe experiments on Benard-Marangoni convection in horizontal layers of two immiscible liquids. Unlike previous experiments, which used gases as the upper fluid, we find a square planform close to onset which undergoes a secondary bifurcation to rolls at higher temperature differences. The scale of the convection pattern is that of the thinner lower fluid layer for which buoyancy and surface tension forces are comparable. The wave number of the pattern near onset agrees with the linear stability prediction for the full two-layer problem. The square planform is in qualitative agreement with recent two-layer weakly nonlinear theories, which fail however to predict the transition to rolls.
Physical Review Letters, 1997
Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, h... more Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in certain mixtures:
Proceedings of the 18th …, 2011
AbstractWe are building a compiler to help map large computations into FPGAs because we are also... more AbstractWe are building a compiler to help map large computations into FPGAs because we are also developing hardware to perform Electrical Impedance Tomography (EIT) in real-time. The EIT inverse problem is non-linear and severely ill-posed and the sampling ...