35,143 research outputs found
Coal-rock interface detector
A coal-rock interface detector is presented which employs a radioactive source and radiation sensor. The source and sensor are separately and independently suspended and positioned against a mine surface of hydraulic pistons, which are biased from an air cushioned source of pressurized hydraulic fluid
Learning medical alarms whilst performing other tasks.
Two studies are reported which first observe, and then attempt to replicate, the cognitive demands of intensive care unit (ICU) activity whilst concurrently learning audible alarms. The first study, an observational study in an ICU ward, showed that the alarms are very frequent and co-occur with some activities more than others. The three most frequently observed activities observed in the ICU were drugs (calculation, preparation and administration), patient observation and talking. The cognitive demands of these activities were simulated in a second, laboratory-based experiment in which alarms were learned. The results showed that performance in the alarm task generally improved as participants were exposed to more repetitions of those alarms, but that performance decrements were observed in the secondary tasks, particularly when there were two or three of them. Some confusions between the alarms persisted to the end of the study despite prolonged exposure to the alarms, confusions which were likely caused by both acoustic and verbal labelling similarities. PRACTITIONER SUMMARY: The cognitive demands of working in an ICU were observed and simulated whilst alarms were learned. Alarms should generally avoid sharing similar rhythmic (and other) characteristics. The simulation task described here could be used for testing alarm learning without requiring a clinical environment
Recoupling matrix elements and decay
Recoupling matrix elements are evaluated, in the harmonic oscillator
approximation, for all possible angular and radial excitations in processes
where quarks recombine. A diagrammatic representation is given. Their use is
demonstrated in calculating the transition potential for rho to two pions in a
pair creation model.Comment: 15 pages, 10 figure
Novel SM-like Higgs decay into displaced heavy neutrino pairs in U(1)' models
We examine the observability of heavy neutrino (nu_h) signatures of a U(1)'
enlarged Standard Model (SM) encompassing three heavy Majorana neutrinos
alongside the known light neutrino states at the the Large Hadron Collider
(LHC). We show that heavy neutrinos can be rather long-lived particles
producing distinctive displaced vertices that can be accessed in the CERN LHC
detectors. We concentrate here on the gluon fusion production mechanism gg ->
H_{1,2} -> nu_h nu_h, where H_1 is the discovered SM-like Higgs and H_2 is a
heavier state, yielding displaced leptons following nu_h decays into weak gauge
bosons. Using data collected by the end of the LHC Run 2, these signatures
would prove to be accessible with negligibly small background.Comment: 30 pages, journal versio
Trends in Outcomes for Young People with Disabilities: Are We Making Progress?
This paper uses the Current Population Survey (CPS) from 1981-2000 to compare long term trends in socio-economic outcomes for youth (aged 15-21) and young adults (aged 22-29) with work limitations to those for youth and young adults without work limitations. We focus on the years 1988 and 1999: years that roughly correspond to the peaks of successive business cycles. We find that prevalence of work limitations declined for males but increased for females, mostly accounted for by growth for African American females. Despite a substantial reduction in the educational attainment gap between young adults with and without disabilities, gaps in employment, earnings, dependency on public programs and poverty widened substantially. These trends could be due to factors that determine whether individuals report themselves to be work-limited, factors that affect individual outcomes regardless of self-reported work limitation status, or both sets of factors
The LHC di-photon excess and Gauge Coupling Unification in Extra Heterotic-String Derived Models
The di-photon excess observed at the LHC can be explained as a Standard Model
singlet that is produced and decays by heavy vector-like colour triplets and
electroweak doublets in one-loop diagrams. The characteristics of the required
spectrum are well motivated in heterotic-string constructions that allow for a
light . Anomaly cancellation of the symmetry
requires the existence of the Standard Model singlet and vector-like states in
the vicinity of the breaking scale. In this paper we show
that the agreement with the gauge coupling data at one-loop is identical to the
case of the Minimal Supersymmetric Standard Model, owing to cancellations
between the additional states. We further show that effects arising from heavy
thresholds may push the supersymmetric spectrum beyond the reach of the LHC,
while maintaining the agreement with the gauge coupling data. We show that the
string inspired model can indeed account for the observed signal and discuss
the feasibility of obtaining viable scalar mass spectrum.Comment: 26 pages. 11 figures. Published versio
On the choice of colliding beams to study deformation effects in relativistic heavy ion collisions
It has been suggested that collisions between deformed shapes will lead to
interesting effects on various observables such as K production and elliptic
flow. Simple formulae can be written down which show how to choose the
colliding beams which will maximise the effects of deformation.Comment: 2 pages, this version supersedes the previous on
Environmental, health and safety assessment of photovoltaics
The environmental, health, and safety (E, H and S) concerns associated with the fabrication, deployment, and decommissioning of photovoltaic (PV) systems in terrestial applications are identified and assessed. Discussion is limited to crystalline silicon technologies. The primary E, H, and S concerns that arise during collector fabrication are associated with occupational exposure to materials of undetermined toxicity or to materials that are known to be hazardous, but for which process control technology may be inadequate. Stricter exposure standards are anticipated for some materials and may indicate a need for further control technology development. Minimizing electric shock hazards is a significant concern during system construction, operation and maintenance, and decommissioning
Giant electrocaloric effect around T
We use molecular dynamics with a first-principles-based shell model potential
to study the electrocaloric effect (ECE) in lithium niobate, LiNbO, and
find a giant electrocaloric effect along a line passing through the
ferroelectric transition. With applied electric field, a line of maximum ECE
passes through the zero field ferroelectric transition, continuing along a
Widom line at high temperatures with increasing field, and along the
instability that leads to homogeneous ferroelectric switching below with
an applied field antiparallel to the spontaneous polarization. This line is
defined as the minimum in the inverse capacitance under applied electric field.
We investigate the effects of pressure, temperature and applied electric field
on the ECE. The behavior we observe in LiNbO should generally apply to
ferroelectrics; we therefore suggest that the operating temperature for
refrigeration and energy scavenging applications should be above the
ferroelectric transition region to obtain large electrocaloric response. We
find a relationship among , the Widom line and homogeneous switching that
should be universal among ferroelectrics, relaxors, multiferroics, and the same
behavior should be found under applied magnetic fields in ferromagnets.Comment: 5 page
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