This paper examines a method for real-time control of non-inductively sustained scenarios in NSTX-U by using TRANSP,
a time-dependent integrated modeling code for prediction and interpretive analysis of tokamak experimental data, as a
simulator. The actuators considered for control in this work are the six neutral beam sources and the plasma boundary
shape. To understand the response of the plasma current, stored energy, and central safety factor to these actuators
and to enable systematic design of control algorithms, simulations were run in which the actuators were modulated and
a linearized dynamic response model was generated. A multi-variable model-based control scheme that accounts for the
coupling and slow dynamics of the system while mitigating the effect of actuator limitations was designed and
simulated. Simulations show that modest changes in the outer gap and heating power can improve the response time of
the system, reject perturbations, and track target values of the controlled values.
Kim, Donghoon; Tracy, Sally J.; Smith, Raymond F.; Gleason, Arianna E.; Bolme, Cindy A.; Prakapenka, Vitali B.; Appel, Karen; Speziable, Sergio; Wicks, June K.; Berryman, Eleanor J.; Han, Sirus K.; Schoelmerich, Markus O.; Lee, Hae Ja; Nagler, Bob; Cunningham, Eric F.; Akin, Minta C.; Asimow, Paul D.; Eggert, Jon H.; Duffy, Thomas S.
The behavior of forsterite, Mg2SiO4, under dynamic compression is of fundamental importance for understanding its phase transformations and high-pressure behavior. Here, we have carried out an in situ X-ray diffraction study of laser-shocked poly- and single-crystal forsterite (a-, b-, and c- orientations) from 19 to 122 GPa using the Matter in Extreme Conditions end-station of the Linac Coherent Light Source. Under laser-based shock loading, forsterite does not transform to the high-pressure equilibrium assemblage of MgSiO3 bridgmanite and MgO periclase, as was suggested previously. Instead, we observe forsterite and forsterite III, a metastable polymorph of Mg2SiO4, coexisting in a mixed-phase region from 33 to 75 GPa for both polycrystalline and single-crystal samples. Densities inferred from X-ray diffraction data are consistent with earlier gas-gun shock data. At higher stress, the behavior observed is sample-dependent. Polycrystalline samples undergo amorphization above 79 GPa. For - and -oriented crystals, a mixture of crystalline and amorphous material is observed to 108 GPa, whereas the -oriented crystal adopts an unknown crystal structure at 122 GPa. The Q values of the first two sharp diffraction peaks of amorphous Mg2SiO4 show a similar trend with compression as those observed for MgSiO3 glass in both recent static and laser-compression experiments. Upon release to ambient pressure, all samples retain or revert to forsterite with evidence for amorphous material also present in some cases. This study demonstrates the utility of femtosecond free-electron laser X-ray sources for probing the time evolution of high-pressure silicates through the nanosecond-scale events of shock compression and release.
A subset of the Fermi-LAT public data for use with NPTFit:
The data here is for use with the Jupyter example notebooks provided with the
main code. Details of the files provided are given below. All files are provided
as numpy arrays binned as nside=128 HEALPix maps.
For the full public data, see:
The data provided in this DataSpace consists of sample training data to be used for Fluorescence Reconstruction Microscopy (FRM) testing. We provide a subset of the keratinocyte (10x magnification) dataset used in our paper, in which interested parties may find more complete information about our data collection methods. Matched pairs of phase contrast and fluorescent images are given. The nuclei were stained using Hoechst 33342 and imaged using a standard DAPI filter set.
The data provided in this DataSpace consists of sample training data to be used for Fluorescence Reconstruction Microscopy (FRM) testing. We provide a subset of the MDCK (20x magnification) dataset used in our paper, in which interested parties may find more complete information about our data collection methods. Matched pairs of DIC and fluorescent images are given. The cells stably expressed E-cadherin:RFP which enabled imaging of junctional fluorescence, while the nuclei were stained using Hoechst 33342 and imaged using a standard DAPI filter set.
We provide all the test data and corresponding predictions for our paper, “Practical Fluorescence Reconstruction Microscopy for High-Content Imaging”. Please refer to the Methods section in this paper for experimental details. For each experimental condition, we provide the input transmitted-light images (either phase contrast or DIC), the ground truth fluorescence images, and the output predicted fluorescence images which should reconstruct the ground truth fluorescence images.
Fractures in geological formations may enable migration of environmentally relevant fluids, as in leakage of CO2 through caprocks in geologic carbon sequestration. We investigated geochemically induced alterations of fracture geometry in Indiana Limestone specimens. Experiments were the first of their kind, with periodic high-resolution imaging using X-ray computed tomography (xCT) scanning while maintaining high pore pressure (100 bar). We studied two CO2-acidified brines having the same pH (3.3) and comparable thermodynamic
disequilibrium but different equilibrated pressures of CO2 (PCO2 values of 12 and 77 bar). High-PCO2 brine has a faster calcite dissolution kinetic rate because of the accelerating effect of carbonic acid. Contrary to expectations, dissolution extents were comparable in the two experiments. However, progressive xCT
images revealed extensive channelization for high PCO2, explained by strong positive feedback between ongoing flow and reaction. The pronounced channel increasingly directed flow to a small region of the fracture, which explains why the overall dissolution was lower than expected. Despite this, flow simulations revealed large increases in permeability in the high-PCO2 experiment. This study shows that the permeability evolution of dissolving fractures will be larger for faster-reacting fluids. The overall mechanism is not because more rock dissolves, as would be commonly assumed, but because of accelerated fracture channelization.
Bertelli, N; Valeo, E.J.; Green, D.L.; Gorelenkova, M.; Phillips, C.K.; Podesta, M.; Lee, J.P.; Wright, J.C.; Jaeger, E.
At the power levels required for significant heating and current drive
in magnetically-confined toroidal plasma, modification of the particle distribution
function from a Maxwellian shape is likely [T. H. Stix, Nucl. Fusion, 15 737
(1975)], with consequent changes in wave propagation and in the location and
amount of absorption. In order to study these effects computationally, both the
finite-Larmor-radius and the high-harmonic fast wave (HHFW), versions of the
full-wave, hot-plasma toroidal simulation code TORIC [M. Brambilla, Plasma Phys.
Control. Fusion 41, 1 (1999) and M. Brambilla, Plasma Phys. Control. Fusion
44, 2423 (2002)], have been extended to allow the prescription of arbitrary velocity
distributions of the form f(v||, v_perp, psi , theta). For hydrogen (H) minority heating of a
deuterium (D) plasma with anisotropic Maxwellian H distributions, the fractional
H absorption varies significantly with changes in parallel temperature but is
essentially independent of perpendicular temperature. On the other hand, for
HHFW regime with anisotropic Maxwellian fast ion distribution, the fractional
beam ion absorption varies mainly with changes in the perpendicular temperature.
The evaluation of the wave-field and power absorption, through the full wave
solver, with the ion distribution function provided by either aMonte-Carlo particle
and Fokker-Planck codes is also examined for Alcator C-Mod and NSTX plasmas.
Non-Maxwellian effects generally tends to increase the absorption with respect to
the equivalent Maxwellian distribution.
The materials include codes and example input / output files for Monte Carlo simulations of lattice chains in the grand canonical ensemble, for determining phase behavior, critical points, and formation of aggregates.
Dielectric tensor for crystalline graphite from X-ray to microwave frequencies, as discussed in the paper "Graphite Revisited" (Draine 2016, Astrophysical Journal, in press). Cross sections for absorption and scattering by graphite spheres and spheroids are also tabulated, as well as Planck-averaged cross sections for absorption and scattering of radiation with a Planck spectrum.