Laser-driven dynamic compression experiments of plastic materials have found surprisingly fast formation of nanodiamonds (ND) via X-ray probing. This mechanism is relevant for planetary models, but could also open efficient synthesis routes for tailored NDs. We investigate the release mechanics of compressed NDs by molecular dynamics simulation of the isotropic expansion of finite size diamond from different P-T states.
View Article and Find Full Text PDFThe Oak Ridge National Laboratory is planning to build the Second Target Station (STS) at the Spallation Neutron Source (SNS). STS will host a suite of novel instruments that complement the First Target Station's beamline capabilities by offering an increased flux for cold neutrons and a broader wavelength bandwidth. A novel neutron imaging beamline, named the Complex, Unique, and Powerful Imaging Instrument for Dynamics (CUPI2D), is among the first eight instruments that will be commissioned at STS as part of the construction project.
View Article and Find Full Text PDFExtreme conditions inside ice giants such as Uranus and Neptune can result in peculiar chemistry and structural transitions, e.g., the precipitation of diamonds or superionic water, as so far experimentally observed only for pure C─H and HO systems, respectively.
View Article and Find Full Text PDFDespite surging interest in molten salt reactors and thermal storage systems, knowledge of the physicochemical properties of molten salts are still inadequate due to demanding experiments that require high temperature, impurity control, and corrosion mitigation. Therefore, the ability to predict these properties for molten salts from first-principles computations is urgently needed. Herein, we developed and compared a machine-learned neural network force field (NNFF) and a reparametrized rigid ion model (RIM) for a prototypical molten salt LiF-NaF-KF (FLiNaK).
View Article and Find Full Text PDFThe synthesis path of the C-Buckyball fullerene from a planar precursor developed by Scott et al. [Science, 2002, 295, 5559] is investigated with density functional theory (DFT) methods. Various theoretically possible closing paths are analysed with respect to structural and energetic properties.
View Article and Find Full Text PDFThe diffusivity of hydrogen is an important property of light water nuclear reactor (LWR) fuel cladding. LWR cladding absorbs hydrogen during normal operation, a contributing factor to embrittlement that decreases the lifetime of the fuel. Mass transport of hydrogen is dictated by an Arrhenius behavior typical of solid state diffusion and the associated activation energy is therefore a property relevant to LWR fuel performance.
View Article and Find Full Text PDFUnlabelled: This work presents a methodology combining SEM, EDS, conventional EBSD, and transmission-EBSD to analyse a recrystallised Zircaloy-4 sheet and cold-worked stress-relieved (CWSR) Zircaloy-4 cladding in unprecedented detail. Second-phase precipitates (SPPs) in Zircaloy-4 specimens were revealed after chemical polishing using a solution containing hydrofluoric acid (HF). Pitting corrosion of Zircaloy-4 specimens was revealed after electropolishing using an electrolyte containing HClO .
View Article and Find Full Text PDFAs a global health organization committed to advocacy and research, Hope Through Healing Hands directed two national polling projects. The 2016 National Survey of Registered Voters Tracking was a longitudinal study to compare and contrast the results from a 2013 national polling project with the same sampling and questionnaire. The primary finding here was that in 2016, conservatives show a statistically significant shift indicating greater, more positive, beliefs in the correlation of contraceptives and women in developing nations and saving lives, although the rest of the populace (moderates and liberals) remained unchanged.
View Article and Find Full Text PDFThe temperature-dependent diffusivity D(T) of hydrogen solute atoms trapped at dislocations-dislocation pipe diffusion of hydrogen-in deformed polycrystalline PdH(x) (x∼10(-3) [H]/[Pd]) has been quantified with quasielastic neutron scattering between 150 and 400 K. We observe diffusion coefficients for trapped hydrogen elevated by one to two orders of magnitude above bulk diffusion. Arrhenius diffusion behavior has been observed for dislocation pipe diffusion and regular bulk diffusion, the latter in well-annealed polycrystalline Pd.
View Article and Find Full Text PDFUltrasound Med Biol
September 2000
Pathologic changes of the intranodal angioarchitecture, as displayed by colour Doppler sonography, were used in recent studies to predict malignant infiltration of superficial lymph nodes. We searched for the underlying histopathologic findings in a prospective study including 100 lymph nodes in 86 patients. In the histopathologic specimens, we evaluated tumour infiltration, distribution of intranodal vessels, hilar structures, thickness of the capsule and tissue alterations (necrosis, sclerosis, lipo-/fibromatosis).
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