5,277 research outputs found
Thermal energy storage material thermophysical property measurement and heat transfer impact
The thermophysical properties of salts having potential for thermal energy storage to provide peaking energy in conventional electric utility power plants were investigated. The power plants studied were the pressurized water reactor, boiling water reactor, supercritical steam reactor, and high temperature gas reactor. The salts considered were LiNO3, 63LiOH/37 LiCl eutectic, LiOH, and Na2B4O7. The thermal conductivity, specific heat (including latent heat of fusion), and density of each salt were measured for a temperature range of at least + or - 100 K of the measured melting point. Measurements were made with both reagent and commercial grades of each salt
Playas of inland Australia
[Abstract] Playas, mostly in the form of salinas, are characteristic of the Australian arid zone. Many are
associated with lunettes in sebkha complexes or assemblages and can be attributed to the deflation
of bare alluvial flats. Many playas are structurally controlled. Lake Eyre, for example, occupies
a downfaulted segment of the crust, and many other playas large and small are associated with
faults. Lakes Frome, Callabonna, Blanche, and Gregory each displays a linear shoreline, but also
and arguably, all are located on a regional structural arc. Lake Gairdner occupies a valley probably
blocked by faulting. Others may be caused by preferential weathering along fracture zones, some
linear but others arcuate. Many salinas are developed in dismembered rivers channels, the position
and pattern of which are structurally determined. But many owe their existence to the interaction
of several of these factors. The various salts precipitated in playas constitute a significant resource,
regional and local, past, present and future
Anomalous hydrodynamics and "normal" fluids in rapidly rotating BECs
In rapidly rotating bose systems we show that there is a region of anomalous
hydrodynamics whilst the system is still condensed, which coincides with the
mean field quantum Hall regime. An immediate consequence is the absence of a
normal fluid in any conventional sense. However, even the superfluid
hydrodynamics is not described by conventional Bernoulli and continuity
equations. We show there are kinematic constraints which connect spatial
variations of density and phase, that the positions of vortices are not the
simplest description of the dynamics of such a fluid (despite their utility in
describing the instantaneous state of the condensate) and that the most compact
description allows solution of some illuminating examples of motion. We
demonstrate, inter alia, a very simple relation between vortices and surface
waves. We show the surface waves can form a "normal fluid" which absorbs energy
and angular momentum from vortex motion in the trap. The time scale of this
process is sensitive to the initial configuration of the vortices, which can
lead to long-lived vortex patches - perhaps related to those observed at JILA.Comment: 4 pages; 1 sentence and references modifie
School-based Understanding of Human Rights in Four Countries: A Commonwealth Study
Teaching/Communication/Extension/Profession,
Effects of culling on badger abundance : implications for tuberculosis control
Culling is often considered as a tool for controlling wildlife diseases that can also infect people or livestock. Culling European badgers Meles meles can cause both positive and negative effects on the incidence of bovine tuberculosis (TB) in cattle. One factor likely to influence the outcome of different badger culling strategies for cattle TB is the reduction in badger population density achieved. However, this reduction is difficult to measure because badgers, being nocturnal and fossorial, are difficult to count. Here, we use indices of badger abundance to measure the population impacts of two culling strategies tested in Britain. The densities of badger setts and latrines recorded before culling were correlated with the densities of badgers captured on initial culls, suggesting that both were indices of actual badger abundance. Widespread 'proactive' culling was associated with a 73% reduction in the density of badger latrines, a 69% reduction in the density of active burrows and a 73% reduction in the density of road killed badgers. This population reduction was achieved by a coordinated effort entailing widespread and repeated trapping over several years. However, this strategy caused only modest reductions in cattle TB incidence in culled areas and elevated incidence in neighbouring unculled areas. Localized 'reactive' culling caused a 26% reduction in latrine density, a 32% reduction in active burrow density and a 10% reduction in the density of road killed badgers, but apparently increased the incidence of cattle TB. These results indicate that the relationship between badger population reduction and TB transmission to cattle is strongly non linear, probably because culling prompts changes in badger behaviour that influence transmission rates. These findings raise serious questions about the capacity of badger culling to contribute to the control of cattle TB in Britain
The Canadian Joint Replacement Registry—what have we learned?
The Canadian Joint Replacement Registry (CJRR) was launched in 2000 through the collaborative efforts of the Canadian Orthopedic Association and the Canadian Institutes for Health Information. Participation is voluntary, and data collected by participating surgeons in the operating room is linked to hospital stay information from administrative databases to compile yearly reports. In the fiscal year 2006–2007, there were 62,196 hospitalizations for hip and knee replacements in Canada, excluding Quebec. This represents a 10-year increase of 101% and a 1-year increase of 6%. Compared to men, Canadian women have higher age-adjusted rates per 105 for both TKA (148 vs. 110) and THA (86 vs. 76). There also exist substantial inter-provincial variations in both age-adjusted rates of arthroplasty and implant utilization that cannot be explained entirely on the basis of differing patient demographics. The reasons for these variations are unclear, but probably represent such factors as differences in provincial health expenditure, efforts to reduce waiting lists, and surgeon preference. The main challenge currently facing the CJRR is to increase procedure capture to > 90%. This is being pursued through a combination of efforts including simplification of the consent process, streamlining of the data collection form, and the production of customized reports with information that has direct clinical relevance for surgeons and administrators. As the CJRR continues to mature, we are optimistic that it will provide clinically important information on the wide range of factors that affect arthroplasty outcome
Desarrollo de formas multietapa en varias situaciones geomorfológicas y a diferentes escalas
[Abstract] That many landforms have their origins in the distant past is highlighted by the multistage concept, whereby the structural properties of bedrock which have been exploited
by shallow groundwaters are taken fully into account. Fractures of various types are par-
ticularly vulnerable to weathering and hence to erosion. Examples are discussed from
various lithological and environmental settings - plutonic, volcanic and sedimentary
rocks, and different climates
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