26,975 research outputs found
Tornado detector and alarm
Automatic device which attaches to an active television set sounds an audible alarm when a tornado is within 29 km (18miles) of device
Warm Inflation with a General Form of the Dissipative Coefficient
We propose and investigate a general form of the dissipative coefficient
in warm inflation. We focus on discussing the
strong dissipative processes in the thermal state of
approximate equilibrium. To this toy model, we give the slow-roll conditions,
the amplitude and the index of the power spectrum under the general form of
dissipative coefficient. Furthermore, the monomial potential and the
hybrid-like potential are analyzed specifically. We conclude that the
cases are worthy further investigation especially.Comment: 24 pages, no figures, to be published on JCA
Study of the modulatory effects of the solar wind on galactic cosmic rays
Mathematical model using Monte Carlo method for modulation of galactic protons by solar win
Study of the modulatory effects of the solar wind on galactic cosmic rays Final report
Modulatory effects of solar wind on galactic cosmic ray
Reversing the Null: Regulation, Deregulation, and the Power of Ideas
It has been said that deregulation was an important source of the recent financial crisis. It may be more accurate, however, to say that a deregulatory mindset was an important source of the crisis - a mindset that, to a very significant extent, grew out of profound changes in academic thinking about the role of government. As scholars of political economy quietly shifted their focus from market failure to government failure over the second half of the twentieth century, they set the stage for a revolution in both government and markets, the full ramifications of which are still only beginning to be understood. This intellectual sea-change generated some positive effects, but also some negative ones, including (it seems) an excessively negative impression of the capacity of government to address problems in the marketplace. Today, as we consider the need for new regulation, particularly in the wake of the financial crisis, another fundamental shift in academic thinking about the role of government may be required - involving nothing less than a reversal of the prevailing null hypothesis in the study of political economy.
SSME single-crystal turbine blade dynamics
A study was performrd to determine the dynamic characteristics of the Space Shuttle Main Engine high pressure fuel turbopump (HPFTP) blades made of single crystal (SC) material. The first and second stage drive turbine blades of HPFTP were examined. The nonrotating natural frequencies were determined experimentally and analytically. The experimental results of the SC second stage blade were used to verify the analytical procedures. The study examined the SC first stage blade natural frequencies with respect to crystal orientation at typical operating conditions. The SC blade dynamic response was predicted to be less than the directionally solidified base. Crystal axis orientation optimization indicated that the third mode interference will exist in any SC orientation
Constraints on the solid dark universe model
If the dark energy is modelled as a relativistic elastic solid then the
standard CDM and CDM models, as well as lattice configurations of
cosmic strings or domain walls, are points in the two-dimensional parameter
space . We present a detailed analysis of the best fitting
cosmological parameters in this model using data from a range of observations.
We find that the is improved by by including the two
parameters and that the CDM model is only the best fit to the
data when a large number of different datasets are included. Using CMB
observations alone we find that and with the addition of
Large-Scale Structure data and . We conclude that the models based on topological defects provide a good
fit to the current data, although CDM cannot be ruled out.Comment: 10 page
Density fluctuations from warm inflation
Thermal fluctuations provide the main source of large scale density
perturbations in warm inflationary models of the early universe. For the first
time, general results are obtained for the power spectrum in the case when the
friction coefficient in the inflaton equation of motion depends on temperature.
A large increase in the amplitude of perturbations occurs when the friction
coefficient increases with temperature. This has to be taken into account when
constructing models of warm inflation. New results are also given for the
thermal fluctuations in the weak regime of warm inflation when the friction
coefficient is relatively small.Comment: 14 pages, 4 figures, ReVTe
Evidence for massive neutrinos from CMB and lensing observations
We discuss whether massive neutrinos (either active or sterile) can reconcile
some of the tensions within cosmological data that have been brought into focus
by the recently released {\it Planck} data. We point out that a discrepancy is
present when comparing the primary CMB and lensing measurements both from the
CMB and galaxy lensing data using CFHTLenS, similar to that which arises when
comparing CMB measurements and SZ cluster counts. A consistent picture emerges
and including a prior for the cluster constraints and BAOs we find that: for an
active neutrino model with 3 degenerate neutrinos, , whereas for a sterile neutrino, in addition to 3 neutrinos
with a standard hierarchy and , and . In both cases there is a significant detection of modification to
the neutrino sector from the standard model and in the case of the sterile
neutrino it is possible to reconcile the BAO and local measurements.
However, a caveat to our result is some internal tension between the CMB and
lensing/cluster observations, and the masses are in excess of those estimated
from the shape of the matter power spectrum from galaxy surveys.Comment: 5 pages, 3 figures, clarifications added, comparison with WMAP-9 plus
high-l added, version accepted in Physical Review Letter
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