30,434 research outputs found
Insurance for autonomous underwater vehicles
The background and practice of insurance for autonomous underwater vehicles (AUVs) are examined. Key topics include: relationships between clients, brokers and underwriters; contract wording to provide appropriate coverage; and actions to take when an incident occurs. Factors that affect cost of insurance are discussed, including level of autonomy, team experience and operating environment. Four case studies from industry and academia illustrate how AUV insurance has worked in practice. The paper concludes by stressing the importance of effective dialogue between client, broker and underwriter to review, assess and reduce risk to the benefit of all parties
Hydrogen bonding in C-methylated nitroanilines : the three-dimensional framework structure of 2-methyl-4-nitroaniline
Peer reviewedPublisher PD
The regional distribution of public expendictures in the UK : an exposition and critique of the Barnett formula
The Barnett formula is the official basis upon which increments to public funds are allocated to the devolved regions of the UK for those parts of the budget that are administered locally. There is considerable controversy surrounding the implications of its strict application for the relevant regions. The existing literature focuses primarily on the equity of the spatial changes to government per capita expenditure that would accompany such a change. In contrast, in this paper we attempt to quantify the system-wide economic consequences-the real, relative resource squeeze that accompanies the financial relative squeeze-on one devolved region, Scotland. The analysis uses a multisectoral regional computable general equilibrium modelling approach. We highlight the importance of population endogeneity, particularly since the population proportions used in the formula are now regularly updated
MGGPOD: a Monte Carlo Suite for Modeling Instrumental Line and Continuum Backgrounds in Gamma-Ray Astronomy
Intense and complex instrumental backgrounds, against which the much smaller
signals from celestial sources have to be discerned, are a notorious problem
for low and intermediate energy gamma-ray astronomy (~50 keV - 10 MeV).
Therefore a detailed qualitative and quantitative understanding of instrumental
line and continuum backgrounds is crucial for most stages of gamma-ray
astronomy missions, ranging from the design and development of new
instrumentation through performance prediction to data reduction. We have
developed MGGPOD, a user-friendly suite of Monte Carlo codes built around the
widely used GEANT (Version 3.21) package, to simulate ab initio the physical
processes relevant for the production of instrumental backgrounds. These
include the build-up and delayed decay of radioactive isotopes as well as the
prompt de-excitation of excited nuclei, both of which give rise to a plethora
of instrumental gamma-ray background lines in addition to continuum
backgrounds. The MGGPOD package and documentation are publicly available for
download from http://sigma-2.cesr.fr/spi/MGGPOD/.
We demonstrate the capabilities of the MGGPOD suite by modeling high
resolution gamma-ray spectra recorded by the Transient Gamma-Ray Spectrometer
(TGRS) on board Wind during 1995. The TGRS is a Ge spectrometer operating in
the 40 keV to 8 MeV range. Due to its fine energy resolution, these spectra
reveal the complex instrumental background in formidable detail, particularly
the many prompt and delayed gamma-ray lines. We evaluate the successes and
failures of the MGGPOD package in reproducing TGRS data, and provide
identifications for the numerous instrumental lines.Comment: 60 pages, 13 figures, 7 tables, accepted for publication in ApJ
The Spectacular Ionized Interstellar Medium of NGC55
We present deep Halpha+[NII], [SII] (6716,6731A) and [OII] (3726,3729A)
images of the highly inclined, actively star--forming SBm galaxy NGC 55,
located in the nearby Sculptor Group. Due to its proximity, NGC 55 provides a
unique opportunity to study the disk--halo interface in a late--type galaxy
with unprecedented spatial resolution. Our images reveal a spectacular variety
of ionized gas features, ranging from giant HII region complexes, to supergiant
filamentary and shell features, to patches of very faint diffuse emission. Many
of these features protrude well above the plane of the galaxy, including a very
faint fragmented shell of emission which is visible at 2.6 kpc above the disk.
We identify candidate `chimneys' extending out of the disk, which could be the
conduits into the halo for hot gas around disk star-forming regions, and could
also provide low-density paths for the passage of UV photons from the disk to
the halo. Several of the identified chimneys are `capped' with clumps of
ionized gas, one of which, located at 1.5 kpc above the disk plane, appears to
be the site of recent star formation. Emission--line ratios
([OII]/Halpha+[NII], [SII]/Halpha+[NII]) constrain the ionization mechanism of
the gas, and our images allow the first measurement of [OII]/Halpha+[NII] in
extra-planar diffuse ionized gas. The diffuse gas is characterized by
emission--line ratios which are enhanced on average by a factor of two compared
to those of bright HII regions. Each line ratio increases in value smoothly
from the cores of HII regions, through the haloes of HII regions, into the
diffuse ionized gas. Such a continuous trend is predicted by models in which
the diffuse gas is ionized by photons produced by massive stars in HII regions.Comment: 19 pages, including 4 figures, plus 2 external tables. Accepted for
publication in the Astronomical Journal. Compressed, postscript versions of
the plates are available at ftp://skysrv.pha.jhu.edu/ferguson
The environmental "trade balance" between Scotland and the rest of the UK : an inter-regional input-output and SAM analysis
We use an inter-regional input-output (IO) and social accounting matrix (SAM) pollution attribution framework to serve as a platform for sub-national environmental attribution and trade balance analysis. While the existence of significant data problems mean that the quantitative results of this study should be regarded as provisional, the inter-regional economy-environment IO and SAM framework for Scotland and the rest of the UK (RUK) allows an illustrative analysis of some very important issues. There are two key findings. The first is that there are large environmental spillovers between the regions of the UK. This has implications in terms of the devolution of responsibility for achieving targets for reductions in emissions levels and the need for policy co-ordination between the UK national and devolved governments. The second finding is that whilst Scotland runs an economic trade deficit with RUK, the environmental trade balance relationship for the main greenhouse gas, CO2, runs in the opposite direction. In other words, the findings of this study suggest the existence of a CO2 trade surplus between Scotland and the rest of the UK. This suggests that Scotland is bearing a net loss in terms of pollutants as a result of inter-union trade. However, if Scotland can carry out key activities, such as electricity generation, using less polluting technology, it is better for the UK as a whole if this type of relationship exists. Thus, the environmental trade balance is an important part of the devolution settlement
Electrical system/environment interactions on the planet Mars
The Martian environment is a diverse environment with which systems will interact in numerous ways. Preliminary thoughts on electrical system/environment interactions which might be of interest to system designers at all stages of system design are presented. These interactions are primarily related to electrical charging, contamination, and Martian surface sand and dust
Lander Trajectory Reconstruction computer program
The Lander Trajectory Reconstruction (LTR) computer program is a tool for analysis of the planetary entry trajectory and atmosphere reconstruction process for a lander or probe. The program can be divided into two parts: (1) the data generator and (2) the reconstructor. The data generator provides the real environment in which the lander or probe is presumed to find itself. The reconstructor reconstructs the entry trajectory and atmosphere using sensor data generated by the data generator and a Kalman-Schmidt consider filter. A wide variety of vehicle and environmental parameters may be either solved-for or considered in the filter process
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