121,178 research outputs found
Ambient temperature catalyst for hydrogen ignition
Low cost, ambient temperature catalyst for reacting hydrogen gas with air in a catalytic cell near the point of evolution at a controlled rate is announced
How to recognise a kick : A cognitive task analysis of drillers’ situation awareness during well operations
Acknowledgements This article is based on a doctoral research project of the first author which was sponsored by an international drilling rig operator. The views presented are those of the authors and should not be taken to represent the position or policy of the sponsor. The authors wish to thank the industrial supervisor and the drilling experts for their contribution and patience, as well as Aberdeen Drilling School for allowing the first author to attend one of their well control courses.Peer reviewedPostprin
A new method to calibrate ionospheric pulse dispersion for UHE cosmic ray and neutrino detection using the Lunar Cherenkov technique
UHE particle detection using the lunar Cherenkov technique aims to detect
nanosecond pulses of Cherenkov emission which are produced during UHE cosmic
ray and neutrino interactions in the Moon's regolith. These pulses will reach
Earth-based telescopes dispersed, and therefore reduced in amplitude, due to
their propagation through the Earth's ionosphere. To maximise the received
signal to noise ratio and subsequent chances of pulse detection, ionospheric
dispersion must therefore be corrected, and since the high time resolution
would require excessive data storage this correction must be made in real time.
This requires an accurate knowledge of the dispersion characteristic which is
parameterised by the instantaneous Total Electron Content (TEC) of the
ionosphere. A new method to calibrate the dispersive effect of the ionosphere
on lunar Cherenkov pulses has been developed for the LUNASKA lunar Cherenkov
experiments. This method exploits radial symmetries in the distribution of the
Moon's polarised emission to make Faraday rotation measurements in the
visibility domain of synthesis array data (i. e. instantaneously). Faraday
rotation measurements are then combined with geomagnetic field models to
estimate the ionospheric TEC. This method of ionospheric calibration is
particularly attractive for the lunar Cherenkov technique as it may be used in
real time to estimate the ionospheric TEC along a line-of-sight to the Moon and
using the same radio telescope.Comment: 4 pages, 2 figures, Proceedings of ARENA 2010, Nantes, France;
doi:10.1016/j.nima.2010.10.12
Experimental studies of vortex flows
This final report describes research work on vortex flows done during a four-year period beginning in March 1984 and funded by NASA Grant NCC2-294 from the Fluid Dynamics Research Branch of NASA Ames Research Center. After a brief introduction of the main topics addressed by the completed research, the accomplishments are summarized in chronological order
Regulation of Arabidopsis 14-3-3 gene expression by GABA.
The function in plants of the non-protein amino acid, gamma-aminobutyric acid (GABA) is poorly understood. In this study, we show that GABA down-regulates the expression of a large sub-set of 14-3-3 gene family members in Arabidopsis thaliana seedlings in a calcium, ethylene and abscisic acid-dependent manner. Gene expression is not affected when seedlings are supplied with glutamate, a precursor of GABA. The repression of 14-3-3 gene expression by GABA is dependent on functional ethylene and abscisic acid signalling pathways, since the response is lost in the etr1-1, abi1-1 and abi2-1 mutants. Calcium measurements show that in contrast to glutamate, GABA does not elicit a cytoplasmic calcium elevation, suggesting that the GABA response is unlikely to be mediated by glutamate receptors, as has been suggested previously. We suggest that in addition to its role as a stress-related metabolite, GABA may regulate gene expression in Arabidopsis, including members of the 14-3-3 gene family
Digital simulation for post-docking response
The digital program, 2BODY, which simulates the translational and rotational motion of two connected rigid bodies and provides both digital and plot output is described. Relative rotation of the bodies at the connection is allowed, thereby providing a model suitable for studying system stability and response during a soft-dock regime. A users manual for the program is given as well as all the details and background pertaining to the equations of motion and mathematical models, integration scheme, and input/output routines
An Expansion Term In Hamilton's Equations
For any given spacetime the choice of time coordinate is undetermined. A
particular choice is the absolute time associated with a preferred vector
field. Using the absolute time Hamilton's equations are
+ (\delta H_{c})/(\delta \pi)=\dot{q}\Theta = V^{a}_{.;a}N\equiv exp(-\int\Theta d \ta)\pi^{N}\pi^N$. Briefly the possibility of a non-standard sympletic form
and the further possibility of there being a non-zero Finsler curvature
corresponding to this are looked at.Comment: 10 page
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