31 research outputs found
Legacy data and cosmological constraints from the angular-size/redshift relation for ultra-compact radio sources
We have re-examined an ancient VLBI survey of ultra-comact radio sources at
2.29 GHz, which gave fringe amplitudes for 917 such objects with total flux
density >0.5 Jy approximately. A number of cosmological investigations based
upon this survey have been published in recent years. We have updated the
sample with respect to both redshift and radio information, and now have full
data for 613 objects, significantly larger than the number (337) used in
earlier investigations. The corresponding angular-size/redshift diagram gives
Omega_m=0.25+0.04/-0.03, Omega_\Lambda=0.97+0.09/-0.13 and K=0.22+0.07/-0.10.
In combination with supernova data, and a simple-minded approach to CMB data
based upon the angular size of the acoustic horizon, our best figures are
Omega_m=0.298+0.025/-0.024, Omega_\Lambda=0.702+0.035/-0.036 and K=
0.000+0.021/-0.019. We have examined simple models of dynamical vacuum energy;
the first, based upon a scalar potential V(phi)=omega_C^2 phi^2/2, gives
w(0)=-1.00+0.06/-0.00, (dw/dz)_0=+0.00/-0.08; in this case conditions at z=0
require particular attention, to preclude behaviour in which phi becomes
singular as z -->infinity. For fixed w limits are w=-1.20+0.15/-0.14. The above
error bars are 68% confidence limits.Comment: 24 pages, 9 figure
Predictive simulations of reactor-scale plasmas fuelled with multiple pellets with the European Transport Simulator
Thermodynamic Analysis of an Integrated Gasification Solid Oxide Fuel Cell Plant with a Kalina Cycle
Airborne Flux Measurements of BVOCs above Californian Oak Forests: Experimental Investigation of Surface and Entrainment Fluxes, OH Densities, and Damköhler Numbers
The article of record as published may be located at http://dx.doi.org/10.1175/JAS-D-13-054.1Airborne flux measurements of isoprene were performed over the Californian oak belts surrounding the
Central Valley. The authors demonstrate for the first time 1) the feasibility of airborne eddy covariance
measurements of reactive biogenic volatile organic compounds; 2) the effect of chemistry on the vertical
transport of reactive species, such as isoprene; and 3) the applicability of wavelet analysis to estimate regional
fluxes of biogenic volatile organic compounds. These flux measurements demonstrate that instrumentation
operating at slower response times (e.g., 1–5 s) can still be used to determine eddy covariance fluxes in the
mixed layer above land, where typical length scales of 0.5–3km were observed. Flux divergence of isoprene
measured in the planetary boundary layer (PBL) is indicative of OH densities in the range of 4–7 3 106
molecules per cubic centimeter and allows extrapolation of airborne fluxes to the surface with Damk€ohler
numbers (ratio between the mixing time scale and the chemical time scale) in the range of 0.3–0.9. Most of the
isoprene is oxidized in the PBL with entrainment fluxes of about 10% compared to the corresponding surface
fluxes. Entrainment velocities of 1–10 cm s21 were measured. The authors present implications for parameterizing
PBL schemes of reactive species in regional and global models
Molecular Dynamics Simulations of Adsorption of Poly(acrylic acid) and Poly(methacrylic acid) on Dodecyltrimethylammonium Chloride Micelle in Water: Effect of Charge Density
Work and play [music] : twelve preliminary pieces for pianoforte /
B.9010 (Publisher number). Caption title.; For piano.; "Reprinted by Allans Music (Australia) Pty. Ltd., Melbourne, by permission of the Associated Board of Royal Schools of Music, London, England, for sale in Australia" -- Cover.; Also available online http://nla.gov.au/nla.mus-vn2746733