9,730 research outputs found
Coal Geology - where to from here?
Coal geologists are under pressure to minimise exploration expenditure, maximise interpretation confidence and produce the results often too soon. This pressure continues to increase as companies are forced to evaluate borderline economic deposits which are usually deeper and more hazardous, such as the Togara North and Togara South projects in Central Queensland. In response to this pressure, coal geologists are having to integrate and utilise every piece of infonnation available including stratigraphic, structural, analytical, geophysical, geotechnical, hydrological and more recently, environmental data. In Australia, coal geologists rely on research to continually improve both data acquisition and data interpretation. Some of these developments are discussed as well as suggestions for improvements in other areas within this paper
Evolution of the bilayer nu = 1 quantum Hall state under charge imbalance
We use high-mobility bilayer hole systems with negligible tunneling to
examine how the bilayer nu = 1 quantum Hall state evolves as charge is
transferred from one layer to the other at constant total density. We map
bilayer nu = 1 state stability versus imbalance for five total densities
spanning the range from strongly interlayer coherent to incoherent. We observe
competition between single-layer correlations and interlayer coherence. Most
significantly, we find that bilayer systems that are incoherent at balance can
develop spontaneous interlayer coherence with imbalance, in agreement with
recent theoretical predictions.Comment: 4 pages, 4 figure
Investigation to relate the chlorophyll and suspended sediment content in the waters of the lower Chesapeake Bay to ERTS-1 imagery
There are no author-identified significant results in this report
Correlation of ERTS multispectral imagery with suspended matter and chlorophyll in lower Chesapeake Bay
The feasibility of using multispectral satellite imagery to monitor the characteristics of estuarine waters is being investigated. Preliminary comparisons of MSS imagery with suspended matter concentrations, particle counts, chlorophyll, transmittance and bathymetry have been made. Some visual correlation of radiance with particulates and chlorophyll has been established. Effects of bathymetry are present, and their relation to transmittance and radiance is being investigated. Greatest detail in suspended matter is revealed by MSS band 5. Near-surface suspended sediment load and chlorophyll can be observed in bands 6 and 7. Images received to date have partially defined extent and location of high suspensate concentrations. Net quantity of suspended matter in the lower Bay has been decreasing since the inception of the study, and represents the diminution of turbid flood waters carried into the Bay in late September, 1972. The results so far point to the utility of MSS imagery in monitoring estuarine water character for the assessment of siltation, productivity, and water types
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Determination of Inorganic Arsenic and Its Organic Metabolites in Urine by Flow Injection Hydride Generation Atomic Absorption Spectrometry
1662-166
Designing adaptive structures for whole life energy savings
Designing structures with minimal environmental impact is emerging as a seriou concern in the construction sector. Conventional structural design practice involves designing first for strength, followed by secondary checks on deflections and other serviceability limits states. If these limits are exceeded, the con-ventional solution has been to add material to increase stiffness. When the design is governed by unpredicta-ble events such as fluctuating loads, strong wind storms or earthquakes, the structure is effectively overde-signed for most of its working life. This paper presents a methodology to design adaptive structures that minimize the whole life energy consumption. The methodology is illustrated on plane pin-jointed trusses, both determinate and indeterminate. Strategically placing actuators allow the internal flow of forces to be ho-mogenized and displacements to be controlled. The actuators only start working when the loads reach a cer-tain threshold. Below this threshold, the structure resists loads mainly passively thereby limiting significantly the operational energy used. It was found that both indeterminate and determinate topologies bring substantial energy savings up to 70% of the total energy
A Systematic Review of the Effects of Urban Living on Suicidality and Self-Harm in the UK and Ireland
We conducted a systematic review to answer the following: (a) Is there any evidence to support increased prevalence of suicidality and self-harm (i.e. self-harm or suicidality) in urban versus rural environments? (b) What aspects of the urban environment pose risk for suicidality and self-harm? Thirty-five studies met our criteria. Our findings reflect a mixed picture, but with a tendency for urban living to be associated with an increased risk of suicidality and self-harm over rural living, particularly for those living in deprived areas. Further research should focus on the clustering and additive effects of risk and protective factors for suicidality and self-harm in urban environments
Vortices in Spatially Inhomogeneous Superfluids
We study vortices in a radially inhomogeneous superfluid, as realized by a
trapped degenerate Bose gas in a uniaxially symmetric potential. We show that,
in contrast to a homogeneous superfluid, an off-axis vortex corresponds to an
anisotropic superflow whose profile strongly depends on the distance to the
trap axis. One consequence of this superflow anisotropy is vortex precession
about the trap axis in the absence of an imposed rotation. In the complementary
regime of a finite prescribed rotation, we compute the minimum-energy vortex
density, showing that in the rapid-rotation limit it is extremely uniform,
despite a strongly inhomogeneous (nearly) Thomas-Fermi condensate density
. The weak radially-dependent contribution () to the vortex distribution, that vanishes with the
number of vortices as , arises from the interplay between
vortex quantum discretness (namely their inability to faithfully support the
imposed rigid-body rotation) and the inhomogeneous superfluid density. This
leads to an enhancement of the vortex density at the center of a typical
concave trap, a prediction that is in quantitative agreement with recent
experiments (cond-mat/0405240). One striking consequence of the inhomogeneous
vortex distribution is an azimuthally-directed, radially-shearing superflow.Comment: 22 RevTeX pages, 20 figures, Submitted to PR
Onset of Interlayer Phase Coherence in a Bilayer Two-Dimensional Electron System: Effect of Layer Density Imbalance
Tunneling and Coulomb drag are sensitive probes of spontaneous interlayer
phase coherence in bilayer two-dimensional electron systems at total Landau
level filling factor . We find that the phase boundary between the
interlayer phase coherent state and the weakly-coupled compressible phase moves
to larger layer separations as the electron density distribution in the bilayer
is imbalanced. The critical layer separation increases quadratically with layer
density difference.Comment: 4 pages, 3 figure
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