2,582 research outputs found
The characteristics of electronic training collars for dogs
A wide range of electronic dog training collars (e-collars) is available in the UK, yet there is no means by which purchasers can meaningfully compare their electrical characteristics at the point of sale. In this research the electrical characteristics of 13 models of e-collar were examined and an approach to ranking the strength of the electrical stimuli was developed. The electrical impedance of dogs’ necks was measured so that e-collars could be tested under realistic conditions. This impedance was found to be about 10kΩ for wet dogs and 640kΩ for dry dogs. Two copies of each of eight e-collar models and one copy of a further five models were tested. The stimuli generated by these collars comprised sequences of short high voltage pulses. There were large differences between e-collar models in the peak voltage, number of pulses and duration of the pulses but little variation between the duplicates. The peak voltage varied with the impedance of the dog, from 6000V at an impedance of 500kΩ to 100V at 5kΩ. The highest voltages were generated for only a few millionths of a second. A stimulus strength ranking index (SSRI) was developed based on the subjective response of human subjects to electrical stimuli. This index is used to compare the strength of e-collars with diverse electrical characteristics. It shows a wide range in the stimulus strengths of collars and that the relationships between ‘momentary’ and ‘continuous’ stimuli for various models differ significantly
Spin drag Hall effect in a rotating Bose mixture
We show that in a rotating two-component Bose mixture, the spin drag between
the two different spin species shows a Hall effect. This spin drag Hall effect
can be observed experimentally by studying the out-of-phase dipole mode of the
mixture. We determine the damping of this mode due to spin drag as a function
of temperature. We find that due to Bose stimulation there is a strong
enhancement of the damping for temperatures close to the critical temperature
for Bose-Einstein condensation.Comment: 1 figur
Developing students' writing in History: Effects of a teacher-designed domain-specific writing instruction
Nearby Gas-Rich Low Surface Brightness Galaxies
We examine the Fisher-Tully cz<1000 km/s galaxy sample to determine whether
it is a complete and representative sample of all galaxy types, including low
surface brightness populations, as has been recently claimed. We find that the
sample is progressively more incomplete for galaxies with (1) smaller physical
diameters at a fixed isophote and (2) lower HI masses. This is likely to lead
to a significant undercounting of nearby gas-rich low surface brightness
galaxies. However, through comparisons to other samples we can understand how
the nearby galaxy counts need to be corrected, and we see some indications of
environmental effects that probably result from the local high density of
galaxies.Comment: 12 page, 2 figures, to appear in Ap
Signatures of Interchange Reconnection: STEREO, ACE and Hinode Observations Combined
Combining STEREO, ACE and Hinode observations has presented an opportunity to
follow a filament eruption and coronal mass ejection (CME) on the 17th of
October 2007 from an active region (AR) inside a coronal hole (CH) into the
heliosphere. This particular combination of `open' and closed magnetic
topologies provides an ideal scenario for interchange reconnection to take
place. With Hinode and STEREO data we were able to identify the emergence time
and type of structure seen in the in-situ data four days later. On the 21st,
ACE observed in-situ the passage of an ICME with `open' magnetic topology. The
magnetic field configuration of the source, a mature AR located inside an
equatorial CH, has important implications for the solar and interplanetary
signatures of the eruption. We interpret the formation of an `anemone'
structure of the erupting AR and the passage in-situ of the ICME being
disconnected at one leg, as manifested by uni-directional suprathermal electron
flux in the ICME, to be a direct result of interchange reconnection between
closed loops of the CME originating from the AR and `open' field lines of the
surrounding CH.Comment: 13 pages, 13 figures, accepted Annales Geophysica
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