14,255 research outputs found
A Pulsed Synchrotron for Muon Acceleration at a Neutrino Factory
A 4600 Hz pulsed synchrotron is considered as a means of accelerating cool
muons with superconducting RF cavities from 4 to 20 GeV/c for a neutrino
factory. Eddy current losses are held to less than a megawatt by the low
machine duty cycle plus 100 micron thick grain oriented silicon steel
laminations and 250 micron diameter copper wires. Combined function magnets
with 20 T/m gradients alternating within single magnets form the lattice. Muon
survival is 83%.Comment: 4 pages, 1 figures, LaTeX, 5th International Workshop on Neutrino
Factories and Superbeams (NuFact 03), 5-11 Jun 2003, New Yor
A service evaluation: EllenorLions Hospices Children and Young Peoples Service: Executive Summary
Between January and June 2011, the EllenorLions Hospices commissioned a team from Canterbury Christ Church University to independently review the Children and Young Peoples Service to evaluate the integrated service model which delivers both palliative care and community oncology to children and young people with life threatening and life limiting illnesses. The project brief was conducted in two phases. In Phase 1 an information review was undertaken and in Phase 2 the effectiveness and usability of the service for service users and staff was analysed by qualitative methods (individual and focus group interviews). 10 families, 4 young people, and 12 Professional/ Support Staff were involved. The evaluation team presented the draft report to the EllenorLions Management Team in June 2011 and the final report was presented in August 2011
Reconfiguring an Irrigation Landscape to Improve Provision of Ecosystem Services
Over-allocation of fresh water resources to consumptive uses, coupled with recurring drought and the prospect of climate change, is compromising the stocks of natural capital in the world’s basins and reducing their ability to provide ecosystem services. To combat this, governments world wide are making significant investment in efforts to improve sharing of water between consumptive uses and the environment, with many investments centred on modernisation of inefficient irrigation delivery systems, and the purchase of water by government for environmental flows. In this study, spatial targeting was applied within a cost-benefit framework to reconfigure agricultural land use in an irrigation district to achieve a 20% reduction in agricultural water use to increase environmental flows and improve the provision of other ecosystem services. We demonstrate using spatial planning and optimisation models that a targeted land use reconfiguration policy approach could potentially increase the net present value of ecosystem services by up to AUS68.7m in economic returns to agriculture which may be only marginally offset by the increased value of ecosystem services resulting from the return of 61 GL of water to the environment.landscape planning, geographic information systems, cost-benefit analysis, irrigation, climate change, water management, spatial targeting, environmental valuation
GALAXY DYNAMICS IN CLUSTERS
We use high resolution simulations to study the formation and distribution of
galaxies within a cluster which forms hierarchically. We follow both dark
matter and baryonic gas which is subject to thermal pressure, shocks and
radiative cooling. Galaxy formation is identified with the dissipative collapse
of the gas into cold, compact knots. We examine two extreme representations of
galaxies during subsequent cluster evolution --- one purely gaseous and the
other purely stellar. The results are quite sensitive to this choice.
Gas-galaxies merge efficiently with a dominant central object while
star-galaxies merge less frequently. Thus, simulations in which galaxies remain
gaseous appear to suffer an ``overmerging'' problem, but this problem is much
less severe if the gas is allowed to turn into stars. We compare the kinematics
of the galaxy population in these two representations to that of dark halos and
of the underlying dark matter distribution. Galaxies in the stellar
representation are positively biased (\ie over-represented in the cluster) both
by number and by mass fraction. Both representations predict the galaxies to be
more centrally concentrated than the dark matter, whereas the dark halo
population is more extended. A modest velocity bias also exists in both
representations, with the largest effect, , found for the more massive star-galaxies. Phase diagrams show that the
galaxy population has a substantial net inflow in the gas representation, while
in the stellar case it is roughly in hydrostatic equilibrium. Virial mass
estimators can underestimate the true cluster mass by up to a factor of 5. The
discrepancy is largest if only the most massive galaxies are used, reflecting
significant mass segregation.Comment: 30 pages, self-unpacking (via uufiles) postscript file without
figures. Eighteen figures (and slick color version of figure 3) and entire
paper available at ftp://oahu.physics.lsa.umich.edu/groups/astro/fews Total
size of paper with figures is ~9.0 Mb uncompressed. Submitted to Ap.J
Nonlocal hydrodynamic influence on the dynamic contact angle: Slip models versus experiment
Experiments reported by Blake et al. [Phys. Fluids. 11, 1995 (1999)] suggest that the dynamic contact angle formed between the free surface of a liquid and a moving solid boundary at a fixed contact-line speed depends on the flow field/geometry near the moving contact line. The present paper examines quantitatively whether or not it is possible to attribute this effect to bending of the free surface due to hydrodynamic stresses acting upon it and hence interpret the results in terms of the so-called ``apparent'' contact angle. It is shown that this is not the case. Numerical analysis of the problem demonstrates that, at the spatial
resolution reported in the experiments, the variations of the ``apparent'' contact angle (defined in two different ways) caused by variations in the flow field, at a fixed contact-line speed, are too small to account for the observed effect. The results clearly indicate that the actual (macroscopic) dynamic contact angle, i.e.\ the one used in fluid mechanics as a boundary condition for the equation determining the free surface shape, must be regarded as dependent not only on the contact-line speed but also on the flow field/geometry in the vicinity of the moving contact line
Multi-Terabyte EIDE Disk Arrays running Linux RAID5
High-energy physics experiments are currently recording large amounts of data
and in a few years will be recording prodigious quantities of data. New methods
must be developed to handle this data and make analysis at universities
possible. Grid Computing is one method; however, the data must be cached at the
various Grid nodes. We examine some storage techniques that exploit recent
developments in commodity hardware. Disk arrays using RAID level 5 (RAID-5)
include both parity and striping. The striping improves access speed. The
parity protects data in the event of a single disk failure, but not in the case
of multiple disk failures.
We report on tests of dual-processor Linux Software RAID-5 arrays and
Hardware RAID-5 arrays using a 12-disk 3ware controller, in conjunction with
250 and 300 GB disks, for use in offline high-energy physics data analysis. The
price of IDE disks is now less than $1/GB. These RAID-5 disk arrays can be
scaled to sizes affordable to small institutions and used when fast random
access at low cost is important.Comment: Talk from the 2004 Computing in High Energy and Nuclear Physics
(CHEP04), Interlaken, Switzerland, 27th September - 1st October 2004, 4
pages, LaTeX, uses CHEP2004.cls. ID 47, Poster Session 2, Track
Jupiter: Its infrared spectrum from 10 to 40 microns
Spectral measurements of the thermal radiation from Jupiter in the 16-40 micrometer band were analyzed under the assumption that pressure broadened H2 transitions are responsible for the bulk of the infrared opacity over most of this spectral interval. Both the vertical pressure-temperature profile and the hydrogen mixing ratio were determined. The derived value of the molecular hydrogen mixing ratio, 0.89 + or - 0.11, is consistent with the solar value, 0.86
Ionization state, excited populations and emission of impurities in dynamic finite density plasmas: I. The generalized collisional-radiative model for light elements
The paper presents an integrated view of the population structure and its role in establishing the ionization state of light elements in dynamic, finite density, laboratory and astrophysical plasmas. There are four main issues, the generalized collisional-radiative picture for metastables in dynamic plasmas with Maxwellian free electrons and its particularizing to light elements, the methods of bundling and projection for manipulating the population equations, the systematic production/use of state selective fundamental collision data in the metastable resolved picture to all levels for collisonal-radiative modelling and the delivery of appropriate derived coefficients for experiment analysis. The ions of carbon, oxygen and neon are used in illustration. The practical implementation of the methods described here is part of the ADAS Project
Redundant Arrays of IDE Drives
The next generation of high-energy physics experiments is expected to gather
prodigious amounts of data. New methods must be developed to handle this data
and make analysis at universities possible. We examine some techniques that use
recent developments in commodity hardware. We test redundant arrays of
integrated drive electronics (IDE) disk drives for use in offline high-energy
physics data analysis. IDE redundant array of inexpensive disks (RAID) prices
now equal the cost per terabyte of million-dollar tape robots! The arrays can
be scaled to sizes affordable to institutions without robots and used when fast
random access at low cost is important. We also explore three methods of moving
data between sites; internet transfers, hot pluggable IDE disks in FireWire
cases, and writable digital video disks (DVD-R).Comment: Submitted to IEEE Transactions On Nuclear Science, for the 2001 IEEE
Nuclear Science Symposium and Medical Imaging Conference, 8 pages, 1 figure,
uses IEEEtran.cls. Revised March 19, 2002 and published August 200
- …