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We measure the turbulent diffusion coefficient of dust grains embedded in magnetorotational turbulence in a protoplanetary disc directly from numerical simulations and compare it to the turbulent viscosity of the flow. The simulations are…

Astrophysics · Physics 2009-11-10 Anders Johansen , Hubert Klahr

Context: The sizes of dust in the interstellar medium follows a distribution where most of the dust mass is in smaller grains. However, the re-distribution from larger grains towards smaller sizes especially by means of rotational…

Astrophysics of Galaxies · Physics 2024-12-04 Stefan Reissl , Philipp Nguyen , Lucas M. Jordan , Ralf S. Klessen

Grain boundary migration is driven by the boundary's curvature and external loads such as temperature and stress. In intercalation electrodes an additional driving force results from Li-diffusion. That is, Li-intercalation induces volume…

Materials Science · Physics 2019-07-03 Ananya Renuka Balakrishna , Yet-Ming Chiang , W. Craig Carter

Charge carrier concentrations in acceptor-doped proton-conducting perovskites are to a large extent determined by the hydration and oxidation of oxygen vacancies, which introduce protons and holes, respectively. First-principles modeling of…

Materials Science · Physics 2015-09-01 Anders Lindman , Paul Erhart , Göran Wahnström

Stress enhanced self-diffusion of Copper on the $\Sigma$3 twin grain boundary was examined with molecular dynamics simulations. The presence of uniaxial tensile stress results in a significant reduction in activation energy for…

Materials Science · Physics 2007-05-23 Kevin M. Crosby

We expand on a previous study of fronts in finite particle number reaction-diffusion systems in the presence of a reaction rate gradient in the direction of the front motion. We study the system via reaction-diffusion equations, using the…

Statistical Mechanics · Physics 2009-11-11 Elisheva Cohen , David A. Kessler , Herbert Levine

We developed a chemical network for modeling the chemistry and non-ideal MHD effects from the collapsing dense molecular clouds to protostellar disks. First, we re-formulated the cosmic-ray desorption rate by considering the variations of…

Solar and Stellar Astrophysics · Physics 2018-05-16 Bo Zhao , Paola Caselli , Zhi-Yun Li

The diffusion of atoms and radicals on interstellar dust grains is a fundamental ingredient for predicting accurate molecular abundances in astronomical environments. Quantitative values of diffusivity and diffusion barriers usually rely…

Astrophysics of Galaxies · Physics 2021-12-22 Viktor Zaverkin , Germán Molpeceres , Johannes Kästner

The formation of helium cavities in coarse-grained materials produces hardening proportional to the number density and size of the cavities and due to the interaction of dislocations with intragranular helium defects. In nanostructured…

Materials Science · Physics 2023-03-28 W. S. Cunningham , Y. Zhang , S. L. Thomas , O. El-Atwani , Y. Wang , J. R. Trelewicz

Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet…

Earth and Planetary Astrophysics · Physics 2015-06-03 Martin Ilgner

We show that molecular dynamics (MD) simulations are capable of reproducing the drag of solute segregation atmospheres by moving grain boundaries (GBs). Although lattice diffusion is frozen out on the MD timescale, the accelerated GB…

Materials Science · Physics 2020-08-13 R. K. Koju , Y. Mishin

Abbreviation. Thermal diffusion is one of the basic processes for the mobility and formation of species on cosmic dust grains. Recent laboratory measurements have found that the diffusion pre-exponential factor can differ from that for…

Astrophysics of Galaxies · Physics 2024-05-09 Long-Fei Chen , Donghui Quan , Jiao He , Yao Wang , Di Li , Thomas Henning

Structural defects, particularly grain boundaries, play a crucial role in governing charge transport and the optoelectronic properties of metal halide perovskites, thereby limiting the performance of devices. Solar cells incorporating…

Materials Science · Physics 2026-04-07 Huyen T Pham , Siyu Yan , Zhou Xu , Weilun Li , Sergey Gorelick , Michael B Johnston , Joanne Etheridge

Yttrium substituted BaZrO3, with nominal composition BaZr0.9Y0.1O3, a ceramic proton conductor, was subject to impedance spectroscopy for temperatures 300 K < T < 715 K at mechanical pressures 1 GPa < p < 2 GPa. The activation energies Ea…

Strongly Correlated Electrons · Physics 2011-06-07 Qianli Chen , Artur Braun , Alejandro Ovalle , Cristian-Daniel Savaniu , Thomas Graule , Nikolai Bagdassarov

Grain boundaries often exhibit ordered atomic structures. Increasing amounts of evidence have been provided by transmission electron microscopy and atomistic computer simulations that different stable and metastable grain boundary…

Materials Science · Physics 2023-02-14 Tobias Brink , Lena Langenohl , Hanna Bishara , Gerhard Dehm

Atomistic computer simulations are applied to investigate the atomic structure, thermal stability, and diffusion processes in Al-Si interphase boundaries as a prototype of metal-ceramic interfaces in composite materials. Some of the most…

Materials Science · Physics 2023-08-24 Ian Chesser , Raj Koju , Akshay Vellore , Yuri Mishin

There are still debates regarding the mechanisms that lead to hot cracking in parts build by additive manufacturing (AM) of non-weldable Ni-based superalloys. This lack of in-depth understanding of the root causes of hot cracking is an…

Oxygen vacancy formation energies play a major role in the electric field assisted abnormal grain growth of technologically relevant polycrystalline perovskite phases. The underlying effect on the atomic scale is assumed to be a…

Materials Science · Physics 2023-03-10 Daniel Mutter , Cong Tao , Daniel F. Urban , Christian Elsässer

We report the application of femtosecond four-wave mixing (FWM) to the study of carrier transport in solution-processed CH3NH3PbI3. The diffusion coefficient was extracted through direct detection of the lateral diffusion of carriers…

Materials Science · Physics 2017-10-11 D. Webber , C. Clegg , A. W. Mason , S. A. March , I. G. Hill , K. C. Hall

Grain boundary self-diffusion of $^{57}$Co, $^{51}$Cr, $^{59}$Fe and $^{54}$Mn in a coarse-grained, single-phase fcc CoCrFeMnNi high entropy alloy is measured in a wide temperature range of 643 to 1273~K in both C- and B-type kinetic…