scholarly journals Expansions for the linear-elastic contribution to the self-interaction force of dislocation curves

2021 ◽  
pp. 1-30
Author(s):  
PATRICK VAN MEURS
Keyword(s):  
Interaction Force ◽  
The Self ◽  
Atomic Scale ◽  
Linear Elastic ◽  
Local Arrangement ◽  
Discretisation Error ◽  
Local Contribution ◽  
Non Local ◽  
First Time ◽  
Local Term

The self-interaction force of dislocation curves in metals depends on the local arrangement of the atoms and on the non-local interaction between dislocation curve segments. While these non-local segment–segment interactions can be accurately described by linear elasticity when the segments are further apart than the atomic scale of size $\varepsilon$ , this model breaks down and blows up when the segments are $O(\varepsilon)$ apart. To separate the non-local interactions from the local contribution, various models depending on $\varepsilon$ have been constructed to account for the non-local term. However, there are no quantitative comparisons available between these models. This paper makes such comparisons possible by expanding the self-interaction force in these models in $\varepsilon$ beyond the O(1)-term. Our derivation of these expansions relies on asymptotic analysis. The practical use of these expansions is demonstrated by developing numerical schemes for them, and by – for the first time – bounding the corresponding discretisation error.

scholarly journals Adaptability of Ultrasonic Lamb Wave Touchscreen to the Variations in Touch Force and Touch Area

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1736
Author(s):  
Zengchong Yang ◽  
Xiucheng Liu ◽  
Bin Wu ◽  
Ren Liu
Keyword(s):  
Lamb Wave ◽  
Weight Coefficient ◽  
The Self ◽  
Reference Database ◽  
Learning Method ◽  
Improved Method ◽  
Large Area ◽  
Localization Model ◽  
Reference Databases ◽  
First Time

Previous studies on Lamb wave touchscreen (LWT) were carried out based on the assumption that the unknown touch had the consistent parameters with acoustic fingerprints in the reference database. The adaptability of LWT to the variations in touch force and touch area was investigated in this study for the first time. The automatic collection of the databases of acoustic fingerprints was realized with an experimental prototype of LWT employing three pairs of transmitter–receivers. The self-adaptive updated weight coefficient of the used transmitter–receiver pairs was employed to successfully improve the accuracy of the localization model established based on a learning method. The performance of the improved method in locating single- and two-touch actions with the reference database of different parameters was carefully evaluated. The robustness of the LWT to the variation of the touch force varied with the touch area. Moreover, it was feasible to locate touch actions of large area with reference databases of small touch areas as long as the unknown touch and the reference databases met the condition of equivalent averaged stress.

scholarly journals Direct observation of a coil-to-helix contraction triggered by vinculin binding to talin

2020 ◽  
Vol 6 (21) ◽  
pp. eaaz4707 ◽  
Author(s):  
Rafael Tapia-Rojo ◽  
Alvaro Alonso-Caballero ◽  
Julio M. Fernandez
Keyword(s):  
Focal Adhesions ◽  
Interaction Force ◽  
Magnetic Tweezers ◽  
Feedback Mechanism ◽  
Force Transmission ◽  
Mechanical Coupling ◽  
Negative Feedback Mechanism ◽  
The Reformation ◽  
Energy Penalty ◽  
First Time

Vinculin binds unfolded talin domains in focal adhesions, which recruits actin filaments to reinforce the mechanical coupling of this organelle. However, it remains unknown how this interaction is regulated and its impact on the force transmission properties of this mechanotransduction pathway. Here, we use magnetic tweezers to measure the interaction between vinculin head and the talin R3 domain under physiological forces. For the first time, we resolve individual binding events as a short contraction of the unfolded talin polypeptide caused by the reformation of the vinculin-binding site helices, which dictates a biphasic mechanism that regulates this interaction. Force favors vinculin binding by unfolding talin and exposing the vinculin-binding sites; however, the coil-to-helix contraction introduces an energy penalty that increases with force, defining an optimal binding regime. This mechanism implies that the talin-vinculin-actin association could operate as a negative feedback mechanism to stabilize force on focal adhesions.

scholarly journals Kaolin based protective barrier in municipal landfills against adverse chemo-mechanical loadings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Partha Das ◽  
Tadikonda Venkata Bharat
Keyword(s):  
Ionic Strength ◽  
High Ionic Strength ◽  
The Self ◽  
Design Parameters ◽  
Layered System ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Landfill Liner ◽  
First Time ◽  
Applied Stresses

AbstractIn this work, we assess the self-sealing and swelling ability of the compacted granular bentonite (GB) under an inorganic salt environment and induced overburden stresses from the landfill waste. The laboratory permeation tests with high ionic strength salt solutions reveal that the GB fails to seal and exhibits a significant mechanical collapse under different applied stresses. The applicability of GB in the form of geosynthetic clay liners as the bottom liner facilities in landfills that produce high ionic strength salt leachates, therefore, remains a serious concern. We propose an additional barrier system based on kaolin, for the first time, to address this problem. The proposed kaolin-GB layered system performs satisfactorily in terms of its sealing and swelling ability even in adverse saline conditions and low overburden stresses. The kaolin improves the osmotic efficiency of the self and also helps the underlying GB layer to seal the inter-granular voids. The estimated design parameters by through-diffusion test suggest that the kaolin-GB layered system effectively attenuates the permeant flux and suitable as a landfill liner.

scholarly journals Revealing noncollinear magnetic ordering at the atomic scale via XMCD

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fridtjof Kielgast ◽  
Ivan Baev ◽  
Torben Beeck ◽  
Federico Pressacco ◽  
Michael Martins
Keyword(s):  
Ground State ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Magnetic Ordering ◽  
Atomic Scale ◽  
Angle Of Incidence ◽  
X Ray ◽  
First Time ◽  
X Ray Absorption ◽  
Magnetic Sublattices

AbstractMass-selected V and Fe monomers, as well as the heterodimer $${\text{Fe}}_1{\text{V}}_1$$ Fe 1 V 1 , were deposited on a Cu(001) surface. Their electronic and magnetic properties were investigated via X-ray absorption (XAS) and X-ray magnetic circular dichroism (XMCD) spectroscopy. Anisotropies in the magnetic moments of the deposited species could be examined by means of angle resolving XMCD, i.e. changing the X-ray angle of incidence. A weak adatom-substrate-coupling was found for both elements and, using group theoretical arguments, the ground state symmetries of the adatoms were determined. For the dimer, a switching from antiparallel to parallel orientation of the respective magnetic moments was observed. We show that this is due to the existence of a noncollinear spin-flop phase in the deposited dimers, which could be observed for the first time in such a small system. Making use of the two magnetic sublattices model, we were able to find the relative orientations for the dimer magnetic moments for different incidence angles.

A dissipative particle dynamics simulation study on phase diagrams for the self-assembly of amphiphilic hyperbranched multiarm copolymers in various solvents

Soft Matter ◽  
2017 ◽  
Vol 13 (36) ◽  
pp. 6178-6188 ◽  
Author(s):  
Haina Tan ◽  
Chunyang Yu ◽  
Zhongyuan Lu ◽  
Yongfeng Zhou ◽  
Deyue Yan
Keyword(s):  
Phase Diagrams ◽  
Simulation Study ◽  
Self Assembly ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
The Self ◽  
Dynamics Simulation ◽  
Dynamics Simulations ◽  
First Time ◽  
Dissipative Particle Dynamics Simulation

This work discloses for the first time the self-assembly phase diagrams of amphiphilic hyperbranched multiarm copolymers in various solvents by dissipative particle dynamics simulations.

THE NON-LOCAL TIME PROBLEM FOR ONE CLASS OF PSEUDODIFFERENTIAL EQUATIONS WITH SMOOTH SYMBOLS

2021 ◽  
Vol 9 (1) ◽  
pp. 107-127
Author(s):  
R. Kolisnyk ◽  
V. Gorodetskyi ◽  
O. Martynyuk
Keyword(s):  
Fundamental Solution ◽  
Initial Function ◽  
Adjoint Operator ◽  
Differentiation Operator ◽  
The Self ◽  
Multipoint Problem ◽  
Time Problem ◽  
Sigma 1 ◽  
Non Local ◽  
Differential Operator Equation

In this paper we investigate the differential-operator equation $$ \partial u (t, x) / \partial t + \varphi (i \partial / \partial x) u (t, x) = 0, \quad (t, x) \in (0, + \infty) \times \mathbb {R} \equiv \Omega, $$ where the function $ \varphi \in C ^ {\infty} (\mathbb {R}) $ and satisfies certain conditions. Using the explicit form of the spectral function of the self-adjoint operator $ i \partial / \partial x $, in $ L_2 (\mathbb {R}) $ it is established that the operator $ \varphi (i \partial / \partial x) $ can be understood as a pseudodifferential operator in a certain space of type $ S $. The evolution equation $ \partial u / \partial t + \sqrt {I- \Delta} u = 0 $, $ \Delta = D_x ^ 2 $, with the fractionation differentiation operator $ \sqrt { I- \Delta} = \varphi (i \partial / \partial x) $, where $ \varphi (\sigma) = (1+ \sigma ^ 2) ^ {1/2} $, $ \sigma \in \mathbb {R} $ is attributed to the considered equation. Considered equation is a nonlocal multipoint problem with the initial function $ f $, which is an element of a space of type $ S $ or type $ S '$ which is a topologically conjugate with a space of type $ S $ space. The properties of the fundamental solution of such a problem are established, the correct solvability of the problem in the half-space $ t> 0 $ is proved, the representation of the solution in the form of a convolution of the fundamental solution with the initial function is found, the behavior of the solution $ u (t, \cdot) $ for $ t \to + \infty $ (solution stabilization) in spaces of type $ S '$.

scholarly journals Using the Split Bregman Algorithm to Solve the Self-repelling Snakes Model

2022 ◽  
Author(s):  
Huizhu Pan ◽  
Jintao Song ◽  
Wanquan Liu ◽  
Ling Li ◽  
Guanglu Zhou ◽  
...  
Keyword(s):  
Evolution Equations ◽  
Active Contour Model ◽  
Operator Splitting ◽  
The Self ◽  
Convergence Time ◽  
Variational Model ◽  
Split Bregman ◽  
Geodesic Active Contour ◽  
Non Local ◽  
Split Bregman Algorithm

AbstractPreserving contour topology during image segmentation is useful in many practical scenarios. By keeping the contours isomorphic, it is possible to prevent over-segmentation and under-segmentation, as well as to adhere to given topologies. The Self-repelling Snakes model (SR) is a variational model that preserves contour topology by combining a non-local repulsion term with the geodesic active contour model. The SR is traditionally solved using the additive operator splitting (AOS) scheme. In our paper, we propose an alternative solution to the SR using the Split Bregman method. Our algorithm breaks the problem down into simpler sub-problems to use lower-order evolution equations and a simple projection scheme rather than re-initialization. The sub-problems can be solved via fast Fourier transform or an approximate soft thresholding formula which maintains stability, shortening the convergence time, and reduces the memory requirement. The Split Bregman and AOS algorithms are compared theoretically and experimentally.

scholarly journals SDSS J211852.96−073227.5: The first non-local, interacting, late-type intermediate Seyfert galaxy with relativistic jets

2020 ◽  
Vol 636 ◽  
pp. L12 ◽  
Author(s):  
E. Järvelä ◽  
M. Berton ◽  
S. Ciroi ◽  
E. Congiu ◽  
A. Lähteenmäki ◽  
...  
Keyword(s):  
Near Infrared ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Late Type ◽  
Host Galaxies ◽  
Relativistic Jets ◽  
Galaxy Interactions ◽  
Non Local ◽  
First Time

It has been often suggested that a tangible relation exists between relativistic jets in active galactic nuclei (AGN) and the morphology of their host galaxies. In particular, relativistic jets may commonly be related to merging events. Here we present for the first time a detailed spectroscopic and morphological analysis of a Seyfert galaxy, SDSS J211852.96−073227.5, at z = 0.26. This source has previously been classified as a gamma-ray emitting narrow-line Seyfert 1 galaxy. We re-observed it with the 6.5 m Clay Telescope and these new, high-quality spectroscopic data have revealed that it is actually an intermediate-type Seyfert galaxy. Furthermore, the results of modelling the Ks-band near-infrared images obtained with the 6.5 m Baade Telescope indicate that the AGN is hosted by a late-type galaxy in an interacting system, strengthening the suggested connection between galaxy interactions and relativistic jets.

scholarly journals Non-Local and Memory Character of Frictional Energy Dissipation on Atomic Scale

Engineering ◽  
2017 ◽  
Vol 09 (01) ◽  
pp. 14-21
Author(s):  
Sergey Yu. Krylov ◽  
Joost W. M. Frenken
Keyword(s):  
Energy Dissipation ◽  
Atomic Scale ◽  
Frictional Energy ◽  
Non Local ◽  
Frictional Energy Dissipation
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