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This presentation provides an overview of the Source Physics Experiments (SPE) conducted at the Nevada National Security Site.
We present results on top quark physics from the CDF and D0 collaborations at the Fermilab Tevatron proton anti-proton collider. These include legacy results from Run II that were published or submitted for publication before mid-2014, as well as a summary of Run I results. The historical perspective of the discovery of the top quark in Run I is also described.
Synthesis conditions, structural, magnetic and transport properties have been studied for SrCo{sub 1-x}Re{sub x}O{sub 3-{delta}} samples with x=0.1, 0.25, 0.5. SrCo{sub 0.9}Re{sub 0.1}O{sub 3-{delta}} forms in air and remains stable on cooling indicating that small amounts of Re{sup 7+} stabilize a B-site disordered Pm-3m phase inhibiting formation of a hexagonal phase observed for SrCoO{sub 3-{delta}}. After oxygenation SrCo{sub 0.9}Re{sub 0.1}O{sub 2.94} becomes ferromagnetic below 125 K and shows metallic-like conductivity with moderate magnetoresistance at low temperatures. Fully oxygenated double perovskite Sr{sub 2}CoReO{sub 6} (x=0.5) forms under reducing conditions and is tetragonal at room temperature. A hysteretic transition to the antiferromagnetic state at low temperatures ({approx}50-60 K) is coupled with a drastic change of electronic and thermal properties. Contrary to previous reports [A. Nag et al., Chem. Mater. 20(13) (2008) 4420-4424] SrCo{sub 0.75}Re{sub 0.25}O{sub 3} is not a partially cation ordered Sr{sub 4}Co{sub 3}ReO{sub 12} phase, but a mixture of two structural and magnetic phases with disordered SrCo{sub 1-xd}Re{sub xd}O{sub 3} and ordered SrCo{sub 1-xo}Re{sub xo}O{sub 3} compositions where xd>0.1 and xo<0.5. - Graphical abstract: Neutron diffraction pattern for SrCo{sub 0.75}Re{sub 0.25}O{sub 3}. SrCo{sub 0.75}Re{sub 0.25}O{sub 3} is not a partially cation ordered Sr{sub 4}Co{sub 3}ReO{sub 12} phase, but a mixture of two structural and magnetic phases with disordered SrCo{sub 1-xd}Re{sub xd}O{sub 3} and ordered SrCo{sub 1-xo}Re{sub xo}O{sub 3} compositions where xd>0.1 and xo<0.5. Highlights: Black-Right-Pointing-Pointer SrCo{sub 0.9}Re{sub 0.1}O{sub 2.94} is a B-site disordered cubic Pm-3m phase. Black-Right-Pointing-Pointer SrCo{sub 0.9}Re{sub 0.1}O{sub 2.94} is ferromagnetic below 125 K with metallic-like conductivity. Black-Right-Pointing-Pointer Sr{sub 2}CoReO{sub 6} is tetragonal at room temperature and antiferromagnetic below {approx}50-60 K. Black-Right-Pointing-Pointer SrCo{sub 0.75}Re{sub 0.25}O{sub 3} is not a partially cation ordered Sr{sub 4}Co{sub 3}ReO{sub 12} phase. Black-Right-Pointing-Pointer SrCo{sub 0.75}Re{sub 0.25}O{sub 3} is a mixture of disordered and ordered perovskites.
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Large Eddy Models (LES) and Single Column Models (SCM) are used in a surrogate climate change 101 to investigate the physical mechanism of low cloud feedbacks in climate models. Enhanced surface-102 driven boundary layer turbulence and shallow convection in a warmer climate are found to be 103 dominant mechanisms in SCMs.
Aimed at reducing deficiencies in representing the Madden-Julian oscillation (MJO) in general circulation models (GCMs), a global model evaluation project on vertical structure and physical processes of the MJO was coordinated. In this paper, results from the climate simulation component of this project are reported. Here, it is shown that the MJO remains a great challenge in these latest generation GCMs. The systematic eastward propagation of the MJO is only well simulated in about one fourth of the total participating models. The observed vertical westward tilt with altitude of the MJO is well simulated in good MJO models but not in the poor ones. Damped Kelvin wave responses to the east of convection in the lower troposphere could be responsible for the missing MJO preconditioning process in these poor MJO models. Several process-oriented diagnostics were conducted to discriminate key processes for realistic MJO simulations. While large-scale rainfall partition and low-level mean zonal winds over the Indo-Pacific in a model are not found to be closely associated with its MJO skill, two metrics, including the low-level relative humidity difference between high- and low-rain events and seasonal mean gross moist stability, exhibit statistically significant correlations with the MJO performance. It is further indicated that increased cloud-radiative feedback tends to be associated with reduced amplitude of intraseasonal variability, which is incompatible with the radiative instability theory previously proposed for the MJO. Finally, results in this study confirm that inclusion of air-sea interaction can lead to significant improvement in simulating the MJO.
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The relative dispersion of cloud and fog droplets has significant impacts on aerosol indirect effects, radiative transfer, and microphysical processes. However, previous studies have been mostly concerned with clouds, with limited studies on fog, particularly those that examine the combined influences of all key physical processes and their roles during fog evolution. As such, this study aims to conduct a comprehensive investigation by examining the relationships between relative dispersion and other microphysical variables, as well as the underlying microphysical and dynamic processes, based on field fog campaigns in polluted and clean conditions. In polluted fog, droplet concentrations are higher, leading to smaller droplets and increased dispersion. The correlation between dispersion and droplet volume-mean radius is positive in the polluted fog, but shifts to negative in clean fog. Here, we attribute the difference to various microphysical processes like aerosol activation, condensation, collision-coalescence, and entrainment-mixing. In polluted fog, high aerosol concentrations, low supersaturations, and strong turbulence (entrainment-mixing) provide suitable conditions for the simultaneous occurrence of droplet condensation and aerosol activation, resulting in a positive correlation between dispersion and volume-mean radius, especially during the fog formation stage. In contrast, during the mature stage in clean fog, condensation is dominant with weak aerosol activation leading to a negative correlation between relative dispersion and volume-mean radius. The collision-coalescence process is more active in the mature stage, increasing radii and leading to the negative correlation between dispersion and volume-mean radius. This result sheds new light on understanding the relative dispersion and mechanisms in fog under different aerosol backgrounds.
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This paper addresses the problem of estimating the present value of electrochemical internal variables in a lithium-ion cell in real time, using readily available measurements of cell voltage, current, and temperature. The variables that can be estimated include any desired set of reaction flux and solid and electrolyte potentials and concentrations at any set of one-dimensional spatial locations, in addition to more standard quantities such as state of charge. The method uses an extended Kalman filter along with a one-dimensional physics-based reduced-order model of cell dynamics. Simulations show excellent and robust predictions having dependable error bounds for most internal variables. (C) 2014 Elsevier B.V. All rights reserved.
A series of simulations was performed to enable interpretation of the material and physical significance of the parameters defined in the Kolmogorov, Johnson and Mehl, and Avrami (KJMA) rate expression commonly used to describe phase boundary controlled reactions of condensed matter. The parameters k, n, and t 0 are shown to be highly correlated, which if unaccounted for seriously challenge mechanistic interpretation. It is demonstrated that rate measurements exhibit an intrinsic uncertainty without precise knowledge of the location and orientation of nucleation with respect to the free volume into which it grows. More significantly, it is demonstrated that the KJMA rate constant k is highly dependent on sample size. However, under the simulated conditions of slow nucleation relative to crystal growth, sample volume and sample anisotropy correction affords a means to eliminate the experimental condition dependence of the KJMA rate constant, k, producing the material-specific parameter, the velocity of the phase boundary, v pb .
A number of physical properties of aminosilicones have been determined experimentally and predicted computationally. It was found that COSMO-RS predicted the densities of the materials under study to within about 4% of the experimentally determined values. Vapor pressure measurements were performed, and all of the aminosilicones of interest were found to be significantly less volatile than the benchmark MEA material. COSMO-RS was reasonably accurate for predicting the vapor pressures for aminosilicones that were thermally stable. The heat capacities of all aminosilicones tested were between 2.0 and 2.3 J/(g.degrees C); again substantially lower than a benchmark 30% aqueous MEA solution. Surface energies for the aminosilicones were found to be 23.3-28.3 dyne/cm and were accurately predicted using the parachor method.
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