467 research outputs found
High Curie temperature Mn 5 Ge 3 thin films produced by non-diffusive reaction
Polycrystalline Mn 5 Ge 3 thin films were produced on SiO 2 using magnetron
sputtering and reactive diffusion (RD) or non-diffusive reaction (NDR). In situ
X-ray diffraction and atomic force microscopy were used to determine the layer
structures, and magnetic force microscopy, superconducting quantum interference
device and ferromagnetic resonance were used to determine their magnetic
properties. RD-mediated layers exhibit similar magnetic properties as MBE-grown
monocrystalline Mn 5 Ge 3 thin films, while NDR-mediated layers show magnetic
properties similar to monocrystalline C-doped Mn 5 Ge 3 C x thin films with
NDR appears as a CMOS-compatible efficient method to
produce good magnetic quality high-curie temperature Mn 5 Ge 3 thin films
Is it time for an endovascular first approach for ruptured thoracoabdominal aortic aneurysms?
Inertial range scaling of scalar flux spectra in uniformly sheared turbulence
A model based on two-point closure theory of turbulence is proposed and
applied to study the Reynolds number dependency of the scalar flux spectra in
homogeneous shear flow with a cross-stream uniform scalar gradient. For the
cross-stream scalar flux, in the inertial range the spectral behavior agrees
with classical predictions and measurements. The streamwise scalar flux is
found to be in good agreement with the results of atmospheric measurements.
However, both the model results and the atmospheric measurements disagree with
classical predictions. A detailed analysis of the different terms in the
evolution equation for the streamwise scalar flux spectrum shows that nonlinear
contributions are governing the inertial subrange of this spectrum and that
these contributions are relatively more important than for the cross-stream
flux. A new expression for the scalar flux spectra is proposed. It allows us to
unify the description of the components in one single expression, leading to a
classical K^-7/3 inertial range for the cross-stream component and to a new
K^-23/9 scaling for the streamwise component that agrees better with
atmospheric measurements than the K^-3 prediction of J. C. Wyngaard and O. R.
Cot\'e [Quart. J. R. Met. Soc. 98, 590 (1972)]
Optimal estimation for Large-Eddy Simulation of turbulence and application to the analysis of subgrid models
The tools of optimal estimation are applied to the study of subgrid models
for Large-Eddy Simulation of turbulence. The concept of optimal estimator is
introduced and its properties are analyzed in the context of applications to a
priori tests of subgrid models. Attention is focused on the Cook and Riley
model in the case of a scalar field in isotropic turbulence. Using DNS data,
the relevance of the beta assumption is estimated by computing (i) generalized
optimal estimators and (ii) the error brought by this assumption alone. Optimal
estimators are computed for the subgrid variance using various sets of
variables and various techniques (histograms and neural networks). It is shown
that optimal estimators allow a thorough exploration of models. Neural networks
are proved to be relevant and very efficient in this framework, and further
usages are suggested
Inertial range scaling of the scalar flux spectrum in two-dimensional turbulence
Two-dimensional statistically stationary isotropic turbulence with an imposed
uniform scalar gradient is investigated. Dimensional arguments are presented to
predict the inertial range scaling of the turbulent scalar flux spectrum in
both the inverse cascade range and the enstrophy cascade range for small and
unity Schmidt numbers. The scaling predictions are checked by direct numerical
simulations and good agreement is observed
Te homogeneous precipitation in Ge dislocation loop vicinity
International audienceHigh resolution microscopies were used to study the interactions of Te atoms with Ge dislocation loops, after a standard n-type doping process in Ge. Te atoms neither segregate nor precipitate on dislocation loops, but form Te-Ge clusters at the same depth as dislocation loops, in contradiction with usual dopant behavior and thermodynamic expectations. Atomistic kinetic Monte Carlo simulations show that Te atoms are repulsed from dislocation loops due to elastic interactions, promoting homogeneous Te-Ge nucleation between dislocation loops. This phenomenon is enhanced by coulombic interactions between activated Te2þ or Te1þ ions
Andrographolide a New Potential Drug for the Long Term Treatment of Rheumatoid Arthritis Disease
Erratum to: Blood or spores? A cautionary note on interpreting cellular debris on human skeletal remains
Emergent endovascular treatment options for thoracoabdominal aortic aneurysm
For a long time, parallel grafting, physician-modified endografts, and, more recently, in situ fenestration were the only go-to endovascular options for ruptured thoracoabdominal aortic aneurysm, offered mixed results, and depended mainly on the operator's and center's experience. As custom-made devices have become an established endovascular treatment option for elective thoracoabdominal aortic aneurysm, they are not a viable option in the emergency setting, as endograft production can take up to 4 months. The development of off-the-shelf (OTS) multibranched devices with a standardized configuration has allowed the treatment of ruptured thoracoabdominal aortic aneurysm with emergent branched endovascular procedures. The Zenith t-Branch device (Cook Medical) was the first readily available graft outside the United States to receive the CE mark (in 2012) and is currently the most studied device for those indications. A new device, the E-nside thoracoabdominal branch endoprosthesis OTS multibranched endograft (Artivion), has been made commercially available, and the GORE EXCLUDER thoracoabdominal branch endoprosthesis OTS multibranched endograft (W. L. Gore and Associates) is expected to be released in 2023. Due to the lack of guidelines on ruptured thoracoabdominal aortic aneurysm, this review summarizes the available treatment options (ie, parallel grafts, physician-modified endografts, in situ fenestrations, and OTS multibranched devices), compares the indications and contraindications, and points out the evidence gaps that should be filled in the next decade
Automatic Mapping of Atrial Fiber Orientations for Patient-Specific Modeling of Cardiac Electromechanics using Image-Registration
Knowledge of appropriate local fiber architecture is necessary to simulate
patient-specific electromechanics in the human heart. However, it is not yet
possible to reliably measure in-vivo fiber directions, especially in human
atria. Thus, we present a method which defines the fiber architecture in
arbitrarily shaped atria using image registration and reorientation methods
based on atlas atria with fibers predefined from detailed histological
observations. Thereby, it is possible to generate detailed fiber families in
every new patient-specific geometry in an automated, time-efficient process. We
demonstrate the good performance of the image registration and fiber definition
on ten differently shaped human atria. Additionally, we show that
characteristics of the electrophysiological activation pattern which appear in
the atlas atria also appear in the patients' atria. We arrive at analogous
conclusions for coupled electro-mechano-hemodynamical computations
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