14,436 research outputs found
Applications of prestressed segmented brittle materials in aerospace structures
Prestressed segmented brittle materials in aerospace structure
Review of the financial and medicolegal implications of nasal fractures seen at St Luke’s Hospital
Simple nasal bone fractures are the third most common type of all fractures leading to numerous patient visits at the Accident & Emergency department. Nasal fractures are commonly over-investigated in St Luke’s hospital leading to a substantial financial burden on our health system. In this article we review the frequency of simple nasal fractures as well as the necessity or otherwise of nasal x-ray imaging in addition to the financial and health consequences that result from nasal x-ray imaging. These issues are also discussed from a legal perspective.peer-reviewe
Digital Nomadism: the nexus of remote working and travel mobility
As the world went into lockdown due to the COVID-19 pandemic outbreak, people worldwide started to experience a ‘new normal.’ This ‘new normal’ has normalized remote-working and resulted in the mainstream adoption of technologies to support virtual collaboration, communication, and work from a distance. While the COVID-19 pandemic resulted in the restriction of mobility as borders were closed, airlines grounded, and daily commutes limited, visions of a potential future of ‘remote-life’ started to take shape. As professionals (and employers) around the world start to realize that they are no longer physically secured to their desks, offices, or work stations, they may now start to consider a future where they are remote-working from ‘exotic’ locations, often with lower costs of living (Phuket, Bali, or Costa Rica?) instead of working from ‘home.’ Companies around the world have extended their remote-working policies, implemented due to COVID, through 2021 and beyond, and are starting to consider a broader shift towards remote (or hybrid) workforce models as a means for reducing overhead costs while supporting employee productivity and wellbeing
High performance structures
Materials selection, structural geometry, proof testing and statistical screening, prestressing, and system energy as tools for designing optimum trusses and other high performance structure
Studies in prestressed and segmented brittle structures
Application of nonlinear bending theory to prestressed and segmented brittle structure
Triggering of Imaging Air Cherenkov Telescopes: PMT trigger rates due to night-sky photons
Imaging air Cherenkov telescopes are usually triggered on a coincidence of
two or sometimes more pixels, with discriminator thresholds in excess of 20
photoelectrons applied for each pixel. These thresholds required to suppress
night-sky background are significantly higher than expected on the basis of a
Poisson distribution in the number of night-sky photoelectrons generated during
the characteristic signal integration time.
We studied noise trigger rates under controlled conditions using an
artificial background light source. Large tails in the PMT amplitude response
to single photoelectrons are identified as a dominant contribution to noise
triggers. The rate of such events is very sensitive to PMT operating
parameters.Comment: 19 pages, latex,epsf, 7 figures appended as uuencoded file, submitted
to Journal of Physics
Performance of high resistivity n+pp+ silicon solar cells under 1 MeV electron irradiation
High resistivity (1250 and 84 ohm-cm) n(+)pp(+) silicon solar cells were irradiated and their performance evaluated as a function of fluence. The greatest degradation in power occurred for the higher resistivity cell. The data were analyzed under open circuit conditions, and the components of V sub oc determined as a function of fluence. It was found that the voltage contributions from the front and back junctions decreased while the base component (V sub B) increased with fluence. The anomalous behavior of V sub B was attributed to an increase in the base minority carrier gradient with fluence. An argument that the increased power degradation in the 1250 ohm-cm cells was attributable to an increased voltage drop in the base is presented. Diffusion lengths calculated under high injection conditions were significantly greater than those determined under low injection. This was attributed to a saturation of recombination centers under high injection conditions
Capability of Cherenkov Telescopes to Observe Ultra-fast Optical Flares
The large optical reflector (~ 100 m^2) of a H.E.S.S. Cherenkov telescope was
used to search for very fast optical transients of astrophysical origin. 43
hours of observations targeting stellar-mass black holes and neutron stars were
obtained using a dedicated photometer with microsecond time resolution. The
photometer consists of seven photomultiplier tube pixels: a central one to
monitor the target and a surrounding ring of six pixels to veto background
events. The light curves of all pixels were recorded continuously and were
searched offline with a matched-filtering technique for flares with a duration
of 2 us to 100 ms. As expected, many unresolved (500 us)
background events originating in the earth's atmosphere were detected. In the
time range 3 to 500 us the measurement is essentially background-free, with
only eight events detected in 43 h; five from lightning and three presumably
from a piece of space debris. The detection of flashes of brightness ~ 0.1 Jy
and only 20 us duration from the space debris shows the potential of this setup
to find rare optical flares on timescales of tens of microseconds. This
timescale corresponds to the light crossing time of stellar-mass black holes
and neutron stars.Comment: Accepted for publication in Astroparticle Physics, 8 pages, 9
figures, 1 tabl
- …