33,065 research outputs found
An investigation of radiative heat transfer in absorbing, emitting, and scattering media
Radiative heat transfer in nonisothermal emitting, absorbing, and scattering medi
Mie-scattering function
Computer program for calculating normalized Mie scattering function
Time and frequency transfer with a microwave link in the ACES/PHARAO mission
The Atomic Clocks Ensemble in Space (ACES/PHARAO mission), which will be
installed on board the International Space Station (ISS), uses a dedicated
two-way Micro-Wave Link (MWL) in order to compare the timescale generated on
board with those provided by many ground stations disseminated on the Earth.
Phase accuracy and stability of this long range link will have a key role in
the success of the ACES/PHARAO experiment. SYRTE laboratory is heavily involved
in the design and development of the data processing software : from
theoretical modelling and numerical simulations to the development of a
software prototype. Our team is working on a wide range of problems that need
to be solved in order to achieve high accuracy in (almost) real time. In this
article we present some key aspects of the measurement, as well as current
status of the software's development.Comment: Proceedings of the European Frequency and Time Forum (EFTF) 2012 held
in Gothenburg, Sweden, April 201
Zero temperature properties of mesons in a vector meson extended linear sigma model
A three flavor linear sigma model with vector and axial-vector mesons is
discussed. Preliminary results concerning on the symmetry breaking pattern, the
question of parameterization, as well as the resulting meson masses are
presented.Comment: 4 pages, 0 figures, submitted to the Hot and Cold Baryonic Matter
(HCBM 2010) conference proceeding
Shuttle flight pressure instrumentation: Experience and lessons for the future
Flight data obtained from the Space Transportation System orbiter entries are processed and analyzed to assess the accuracy and performance of the Development Flight Instrumentation (DFI) pressure measurement system. Selected pressure measurements are compared with available wind tunnel and computational data and are further used to perform air data analyses using the Shuttle Entry Air Data System (SEADS) computation technique. The results are compared to air data from other sources. These comparisons isolate and demonstrate the effects of the various limitations of the DFI pressure measurement system. The effects of these limitations on orbiter performance analyses are addressed, and instrumentation modifications are recommended to improve the accuracy of similar fight data systems in the future
Survival of Fecal Contamination Indicator Organisms in Soil
Soils amended with human or animal waste may result in pathogen contamination of ground and surface water. Because temperature has been shown to affect pathogen survival, two laboratory studies were conducted to evaluate the impact of extremes in temperature on bacterial and viral pathogen indicator die-off in soil. A Captina silt loam was amended with broiler litter (0.1 g/g dry soil), septic tank effluent, or Escherichia coli (ATCC 13706) culture (both at 0.04 and 0.1 mL/g dry soil in the two respective studies), incubated at 5 and 35°C, and analyzed over time to determine the number of fecal coliform, E. coli, and coliphage remaining. Pathogen indicator die-off rate constants (k) for all indicator- temperature-treatment combinations were determined by first-order kinetics. For all three pathogen indicators, die-off was significantly more rapid at 35°C than at 5°C. In both studies, fecal coliform die-off rates were not different from E. coli die-off rates across each temperature-treatment combination. Levels of these bacterial indicators appeared in a ratio of 1:0.94 with 95% confidence intervals at 0.89 and 0.99 in the E. coli- and litter-amended soils. Die-off of the viral indicator was significantly slower than the die-off of the bacterial indicators at 5°C in litter-amended soil. Die-off of the bacterial indicator, E. coli, in soil amended with E. coli culture was not significantly different than die-off in soil amended with broiler litter at 5 or 35°C in the two studies. Because the higher incubation temperature increased die-off rates for all three indicators, it is expected that the potential for contamination of ground and surface water decreases with increasing temperature
High aspect reactor vessel and method of use
An improved bio-reactor vessel and system useful for carrying out mammalian cell growth in suspension in a culture media are presented. The main goal of the invention is to grow and maintain cells under a homogeneous distribution under acceptable biochemical environment of gas partial pressures and nutrient levels without introducing direct agitation mechanisms or associated disruptive mechanical forces. The culture chamber rotates to maintain an even distribution of cells in suspension and minimizes the length of a gas diffusion path. The culture chamber design is presented and discussed
A Strictly Single-Site DMRG Algorithm with Subspace Expansion
We introduce a strictly single-site DMRG algorithm based on the subspace
expansion of the Alternating Minimal Energy (AMEn) method. The proposed new MPS
basis enrichment method is sufficient to avoid local minima during the
optimisation, similarly to the density matrix perturbation method, but
computationally cheaper. Each application of to in the
central eigensolver is reduced in cost for a speed-up of ,
with the physical site dimension. Further speed-ups result from cheaper
auxiliary calculations and an often greatly improved convergence behaviour.
Runtime to convergence improves by up to a factor of 2.5 on the Fermi-Hubbard
model compared to the previous single-site method and by up to a factor of 3.9
compared to two-site DMRG. The method is compatible with real-space
parallelisation and non-abelian symmetries.Comment: 9 pages, 6 figures; added comparison with two-site DMR
Spectral functions and time evolution from the Chebyshev recursion
We link linear prediction of Chebyshev and Fourier expansions to analytic
continuation. We push the resolution in the Chebyshev-based computation of
many-body spectral functions to a much higher precision by deriving a
modified Chebyshev series expansion that allows to reduce the expansion order
by a factor . We show that in a certain limit the Chebyshev
technique becomes equivalent to computing spectral functions via time evolution
and subsequent Fourier transform. This introduces a novel recursive time
evolution algorithm that instead of the group operator only involves
the action of the generator . For quantum impurity problems, we introduce an
adapted discretization scheme for the bath spectral function. We discuss the
relevance of these results for matrix product state (MPS) based DMRG-type
algorithms, and their use within dynamical mean-field theory (DMFT). We present
strong evidence that the Chebyshev recursion extracts less spectral information
from than time evolution algorithms when fixing a given amount of created
entanglement.Comment: 12 pages + 6 pages appendix, 11 figure
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