29,100 research outputs found
Infrared diode laser spectroscopy of the fundamental band of NF(a1Δ)
Thirty-one lines of the fundamental vibration–rotation band of the NF free radical in its a 1 state have been detected in absorption near 8.6 µm using a tunable infrared diode laser. Linewidths were Doppler limited and several transitions were accompanied by resolved hyperfine structure due to fluorine and nitrogen nuclear moments. Wave number calibration using accurately determined N2O lines yielded v0 = 1165.952±0.001 cm^−1 for the band center. Rotational and centrifugal distortion constants for both v = 0 and 1 states have also been determined
Diffusion algorithms and data reduction routine for onsite launch predictions for the transport of Titan 3 C exhaust effluents
The NASA/MSFC multilayer diffusion algorithms have been specialized for the prediction of the surface impact for the dispersive transport of the exhaust effluents from the launch of a Titan 3 vehicle. This specialization permits these transport predictions to be made at the launch range in real time so that the effluent monitoring teams can optimize their monitoring grids. Basically, the data reduction routine requires just the meteorology profiles for the thermodynamics and kinematics of the atmosphere as an input. These profiles are graphed along with the resulting exhaust cloud rise history, the center line concentrations and dosages, and the hydrogen chloride isopleths
Three-Body Capture of Irregular Satellites: Application to Jupiter
We investigate a new theory of the origin of the irregular satellites of the
giant planets: capture of one member of a ~100-km binary asteroid after tidal
disruption. The energy loss from disruption is sufficient for capture, but it
cannot deliver the bodies directly to the observed orbits of the irregular
satellites. Instead, the long-lived capture orbits subsequently evolve inward
due to interactions with a tenuous circumplanetary gas disk.
We focus on the capture by Jupiter, which, due to its large mass, provides
the most stringent test of our model. We investigate the possible fates of
disrupted bodies, the differences between prograde and retrograde captures, and
the effects of Callisto on captured objects. We make an impulse approximation
and discuss how it allows us to generalize capture results from equal-mass
binaries to binaries with arbitrary mass ratios.
We find that at Jupiter, binaries offer an increase of a factor of ~10 in the
capture rate of 100-km objects as compared to single bodies, for objects
separated by tens of radii that approach the planet on relatively low-energy
trajectories. These bodies are at risk of collision with Callisto, but may be
preserved by gas drag if their pericenters are raised quickly enough. We
conclude that our mechanism is as capable of producing large irregular
satellites as previous suggestions, and it avoids several problems faced by
alternative models.Comment: 39 pages, 12 figures, 1 table, submitted to Icaru
Ricci flows with unbounded curvature
We show that any noncompact Riemann surface admits a complete Ricci flow
g(t), t\in[0,\infty), which has unbounded curvature for all t\in[0,\infty).Comment: 12 pages, 1 figure; updated reference
Relative Decompression Risks of Spacecraft Cabin Atmospheres - Comparision of Gases Using Miniature Pigs Final Report
Using miniature pigs for analysis of altitude decompression sickness and relative decompression hazards of various cabin atmospheres of inert gase
Health effects of home energy efficiency interventions in England: a modelling study
Objective: To assess potential public health impacts of changes to indoor air quality and temperature due to energy efficiency retrofits in English dwellings to meet 2030 carbon reduction targets. Design: Health impact modelling study. Setting: England. Participants: English household population. Intervention: Three retrofit scenarios were modelled: (1) fabric and ventilation retrofits installed assuming building regulations are met. (2) As with scenario (1) but with additional ventilation for homes at risk of poor ventilation. (3) As with scenario (1) but with no additional ventilation to illustrate the potential risk of weak regulations and non-compliance. Main Outcome: Primary outcomes were changes in quality adjusted life years (QALYs) over 50 years from cardiorespiratory diseases, lung cancer, asthma and common mental disorders due to changes in indoor air pollutants, including: second-hand tobacco smoke, PM2.5 from indoor and outdoor sources, radon, mould, and indoor winter temperatures. Results: The modelling study estimates showed that scenario (1) resulted in positive effects on net mortality and morbidity of 2,241 (95% credible intervals (CI) 2,085 to 2,397) QALYs per 10,000 persons over 50 years due to improved temperatures and reduced exposure to indoor pollutants, despite an increase in exposure to outdoor–generated PM2.5. Scenario (2) resulted in a negative impact of -728 (95% CI -864 to -592) QALYs per 10,000 persons over 50 years due to an overall increase in indoor pollutant exposures. Scenario (3) resulted in -539 (95% CI -678 to -399) QALYs per 10,000 persons over 50 years due to an increase in indoor exposures despite targeting. Conclusions: If properly implemented alongside ventilation, energy efficiency retrofits in housing can improve health by reducing exposure to cold and air pollutants. Maximising the health benefits requires careful understanding of the balance of changes in pollutant exposures, highlighting the importance of ventilation to mitigate the risk of poor indoor air quality
Climigration? Population and climate change in Arctic Alaska
Residents of towns and villages in Arctic Alaska live on “the front line of climate change.” Some communities face immediate threats from erosion and flooding associated with thawing permafrost, increasing river flows, and reduced sea ice protection of shorelines. The term climigration, referring to migration caused by climate change, originally was coined for these places. Although initial applications emphasized the need for government relocation policies, it has elsewhere been applied more broadly to encompass unplanned migration as well. Some historical movements have been attributed to climate change, but closer study tends to find multiple causes, making it difficult to quantify the climate contribution. Clearer attribution might come from comparisons of migration rates among places that are similar in most respects, apart from known climatic impacts. We apply this approach using annual 1990–2014 time series on 43 Arctic Alaska towns and villages. Within-community time plots show no indication of enhanced out-migration from the most at-risk communities. More formally, there is no significant difference between net migration rates of at-risk and other places, testing several alternative classifications. Although climigration is not detectable to date, growing risks make either planned or unplanned movements unavoidable in the near future
Herwig++ 2.0 Release Note
A new release of the Monte Carlo program Herwig++ (version 2.0) is now
available. This is the first version of the program which can be used for
hadron-hadron physics and includes the full simulation of both initial- and
final-state QCD radiation.Comment: Source code and additional information available at
http://hepforge.cedar.ac.uk/herwig
Existence of Ricci flows of incomplete surfaces
We prove a general existence result for instantaneously complete Ricci flows
starting at an arbitrary Riemannian surface which may be incomplete and may
have unbounded curvature. We give an explicit formula for the maximal existence
time, and describe the asymptotic behaviour in most cases.Comment: 20 pages; updated to reflect galley proof correction
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