Pneumatic separator gives quick release to heavy loads

Pneumatic separator, using applied pressure, quickly releases restraining devices securing heavy loads. With minor modifications this separator can be used as a coupling device

Non-linear vortex dynamics and transient effects in ferromagnetic disks

We report a time resolved imaging and micromagnetic simulation study of the relaxation dynamics of a magnetic vortex in the non-linear regime. We use time-resolved photoemission electron microscopy and micromagnetic calculations to examine the emergence of non-linear vortex dynamics in patterned Ni80Fe20 disks in the limit of long field pulses. We show for core shifts beyond ~20-25% of the disk radius, the initial motion is characterized by distortions of the vortex, a transient cross-tie wall state, and instabilities in the core polarization that influence the core trajectories.Comment: 11 pages, 3 figures, submitted to Phys. Rev. Let

Mathematical Analysis and Simulations of the Neural Circuit for Locomotion in Lamprey

We analyze the dynamics of the neural circuit of the lamprey central pattern generator (CPG). This analysis provides insights into how neural interactions form oscillators and enable spontaneous oscillations in a network of damped oscillators, which were not apparent in previous simulations or abstract phase oscillator models. We also show how the different behaviour regimes (characterized by phase and amplitude relationships between oscillators) of forward/backward swimming, and turning, can be controlled using the neural connection strengths and external inputs.Comment: 4 pages, accepted for publication in Physical Review Letter

Where My Books Go: Choice and Place in Digital Reading

Digital reading is a topic of rising interest in digital libraries, particularly in terms of optimizing the reading experience. However, there is relatively little data on the patterns of digital reading, including issues of where and what users read, and how they organize, plan and conduct their reading sessions. This paper reports the first data on mobile reading, combining insights from three different studies of users, including diary studies, interviews and ethnomethodological work. The data reveals that reading often depends on highly developed and rehearsed practices, especially when the reading is related to study or research. From this, we are able to identify a number of opportunities for further digital library research to better support the needs of users

Analyses of Dental Pulp in Restored Teeth

Restored teeth were extracted from test animals at four time intervals (1 hour, 1 day, 1 week, and 3 months) following amalgam insertion. Extracted teeth were frozen in liquid nitrogen, cryo-fractured so as to expose the pulps and then freeze-dried. Pulps were analyzed for mercury content by energy dispersive spectrometry (EDS) and atomic absorption spectrophotometry (AAS). Mercury levels appeared below the detection limits of EDS but could be detected by AAS which showed the highest readings seven days after amalgam insertion

The energetic consequence of specific dynamic action in southern bluefin tuna Thunnus maccoyii

Copyright © 2007 The Company of BiologistsThe effect of feeding on the rate of oxygen consumption (O2) of four groups of three southern bluefin tuna Thunnus maccoyii (SBT) was examined in a large static respirometer at water temperatures of 18.2-20.3°C. Six feeding events of rations between 2.1-8.5% body mass (%Mb) of Australian sardines (Sardinops neopilchardus) were recorded (two of the groups were fed twice). Before feeding, fish swam between 0.71 and 1.4 body lengths s-1 (BL s-1) and the routine metabolic rate (RMR) was 366±32.5 mg kg-1 h-1 (mean ± s.e.m.). For all trials, O2 was elevated post feeding, presumably as a result of specific dynamic action (SDA). Swimming velocity was also elevated post feeding for periods similar to that of O2 (between 20-45 h, longest for the largest rations). Post feeding swimming velocity increased to between 0.87-2.6 BL s-1 and was also dependent on ration consumed. It is suggested that the purpose of increased post-feeding swimming velocity was to increase ventilation volume as a response to the enhanced metabolic demand associated with SDA. Peak post-prandial O2 increased linearly with ration size to a maximum of 1290 mg kg-1 h-1, corresponding to 2.8 times the RMR. When converted to its energy equivalent, total magnitude of SDA was linearly correlated with ration size to a maximum of 192 kJ kg-1 h-1, and as a proportion of gross energy ingested (SDA coefficient), it averaged 35±2.2%. These results demonstrate that, although the factorial increase of SDA in SBT is similar to that of other fish species, the absolute energetic cost of SDA is much higher. These results support the contention that tuna are energy speculators, gambling high rates of energy expenditure for potentially higher rates of energy returns. The ration that southern bluefin tuna require to equal the combined metabolic costs of SDA and RMR is estimated in this study to be 3.5%Mb of Australian sardines per day.Q. P. Fitzgibbon, R. S. Seymour, D. Ellis and J. Buchana

Polarity Reversal of a Magnetic Vortex Core by a Unipolar, Nonresonant In-plane Pulsed Magnetic Field

We report the polarity reversal of a magnetic vortex core using a nonresonant in-plane pulsed magnetic field of arbitrary waveform studied using time-resolved x-ray photoemission electron microscopy and micromagnetic simulations. The imaging and simulations show that a 5 mT pulse, higher than the critical field for nonlinear effects, effectively leads to the randomization of the vortex core polarity. The micromagnetic simulations further show that the onset of stochastic core polarity randomization does not necessarily coincide with the critical reversal field, leading to a field window for predictable core reversal

Polarity Reversal of a Magnetic Vortex Core by a Unipolar, Nonresonant In-plane Pulsed Magnetic Field

We report the polarity reversal of a magnetic vortex core using a nonresonant in-plane pulsed magnetic field of arbitrary waveform studied using time-resolved x-ray photoemission electron microscopy and micromagnetic simulations. The imaging and simulations show that a 5 mT pulse, higher than the critical field for nonlinear effects, effectively leads to the randomization of the vortex core polarity. The micromagnetic simulations further show that the onset of stochastic core polarity randomization does not necessarily coincide with the critical reversal field, leading to a field window for predictable core reversal