88,805 research outputs found
Electronic motor control system Patent
Electronic circuit system for controlling electric motor spee
Night-time accidents: a scoping study. Report to The AA Motoring Trust and Rees Jeffreys Road Fund
Context:
Only a quarter of all travel by car drivers is undertaken between the hours of
19.00 and 08.00, but it is in this period that 40 percent of fatal and serious
injuries are sustained by drivers. This indicates that car travel at night carries a
greater risk of being killed or seriously injured than does travel during the day.
The literature indicates that disproportionate numbers of young drivers,
especially young men, are injured at night. But to be able to introduce
measures targeted at this group more needs to be known about the purpose of
their journeys, the types of roads they travel on, and how far they drive and at
what times in the evening and at night.
Older drivers tend to have fewer accidents at night, but little is currently known
about how much can be accounted for by exposure related to their driving
patterns. People over the age of 60 years form about 20 percent of the
population, yet they make up over a quarter of traffic fatalities.
These two groups of young and older drivers have been selected for study with
the following aims:
(a) to assess what information exists which relates to night-time exposure by
activity and by group (young and older);
(b) to assess what is known about exposure and risk to young and older drivers
at night, in conjunction with an analysis of relevant accident data to provide a
picture of the size of the potential problem areas, and gaps in current
knowledge;
(c) to identify people’s concerns, attitudes and beliefs with regard to the
problems of night-time driving; and
(d) to provide the basis for decision on what measures might be brought to bear
on the problem, and what further research would be needed in order to point to
focused action.
This scoping study is in two parts and provides an assessment of the
information available and hence the gaps in our knowledge on the nature and
extent of night-time driving, and the risks involved at these times. The first
part assesses the available data, and the second uses focus groups to gather the
views of drivers themselves, together with their concerns, attitudes and beliefs
with regard to the problems of night-time driving.
The measurement of exposure, or amount of travel by car, of drivers of
different age and gender is central to the assessment of the risk of being killed
or injured in a road traffic accident. In this study, the measure of exposure used
is distance travelled per person per year. This has been combined with casualty
data to make preliminary assessments of risk to people of different ages and
gender of driving at during the daytime and at night
Physical Origin of Density Dependent Force of the Skyrme Type within the Quark Meson Coupling Model
A density dependent, effective nucleon-nucleon force of the Skyrme type is
derived from the quark-meson coupling model -- a self-consistent, relativistic
quark level description of nuclear matter. This new formulation requires no
assumption that the mean scalar field is small and hence constitutes a
significant advance over earlier work. The similarity of the effective
interaction to the widely used SkM force encourages us to apply it to a
wide range of nuclear problems, beginning with the binding energies and charge
distributions of doubly magic nuclei. Finding acceptable results in this
conventional arena, we apply the same effective interaction, within the
Hartree-Fock-Bogoliubov approach, to the properties of nuclei far from
stability. The resulting two neutron drip lines and shell quenching are quite
satisfactory. Finally, we apply the relativistic formulation to the properties
of dense nuclear matter in anticipation of future application to the properties
of neutron stars.Comment: 2 references added, some changes in the tex
Advection-Dominated Accretion with Infall and Outflows
We present self-similar solutions for advection-dominated accretion flows
with radial viscous force in the presence of outflows from the accretion flow
or infall. The axisymmetric flow is treated in variables integrated over polar
sections and the effects of infall and outflows on the accretion flow are
parametrised for possible configurations compatible with the self-similar
solution. We investigate the resulting accretion flows for three different
viscosity laws and derive upper limits on the viscosity parameter alpha. In
addition, we find a natural connection to non-rotating and spherical accretion
with turbulent viscosity, which is assumed to persist even without differential
rotation. Positive Bernoulli numbers for advection-dominated accretion allow a
fraction of the gas to be expelled in an outflow and the upper limit on the
viscosity predicts that outflows are inevitable for equations of state close to
an ideal gas.Comment: 17 pages, 9 figures, accepted for publication in the Astrophysical
Journa
Range-resolved signal processing for fibre segment interferometry applied to dynamic long-gauge length strain sensing
A range-resolved interferometric signal processing technique using sinusoidal optical frequency modulation is applied to fibre segment interferometry. Here, six optical fibre segments of gauge length 12.5 cm are used as interferometric strain sensors and are formed between seven weak, broadband fibre Bragg gratings, acting as in-fibre partial reflectors. In a very simple and cost-effective optical setup using injection current modulation of a laser diode source, interferometric measurement of acoustic wave propagation in a metal rod is used to demonstrate the capabilities of the technique
Unusual identities for QCD at tree-level
We discuss a set of recently discovered quadratic relations between gauge
theory amplitudes. Such relations give additional structural simplifications
for amplitudes in QCD. Remarkably, their origin lie in an analogous set of
relations that involve also gravitons. When certain gluon helicities are
flipped we obtain relations that do not involve gravitons, but which refer only
to QCD.Comment: Talk given at XIV Mexican School on Particles and Fields, Morelia,
Nov. 201
Monodromy and Jacobi-like Relations for Color-Ordered Amplitudes
We discuss monodromy relations between different color-ordered amplitudes in
gauge theories. We show that Jacobi-like relations of Bern, Carrasco and
Johansson can be introduced in a manner that is compatible with these monodromy
relations. The Jacobi-like relations are not the most general set of equations
that satisfy this criterion. Applications to supergravity amplitudes follow
straightforwardly through the KLT-relations. We explicitly show how the
tree-level relations give rise to non-trivial identities at loop level.Comment: 28 pages, 8 figures, JHEP
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