Time variant extension problems of Nehari type and the band method

1991 ◽  
pp. 309-323 ◽  
Author(s):  
I. Gohberg ◽  
M. A. Kaashoek ◽  
H. J. Woerdeman
Keyword(s):  
Band Method

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

Nudged Elastic Band Method for Molecular Reactions Using Energy-Weighted Springs Combined with Eigenvector Following

2021 ◽  
Author(s):  
Vilhjálmur Ásgeirsson ◽  
Benedikt Orri Birgisson ◽  
Ragnar Bjornsson ◽  
Ute Becker ◽  
Frank Neese ◽  
...  
Keyword(s):  
Elastic Band ◽  
Band Method ◽  
Molecular Reactions

scholarly journals CH4 dissociation on the Pd/Cu(111) surface alloy: A DFT study

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 790-798
Author(s):  
Aykan Akça
Keyword(s):  
Catalytic Activity ◽  
Adsorption Energy ◽  
Lower Cost ◽  
Relative Energy ◽  
Catalyst Design ◽  
Elastic Band ◽  
Efficient Catalyst ◽  
Energy Diagram ◽  
Band Method ◽  
Pure Cu

AbstractThe periodic four-layered model of the pure Cu(111) surface has been considered, and the effect of doping with palladium on CH4 dissociation has been investigated. The most stable adsorption geometries of CHx species (x = 1–4) and H atom on the PdCu(111) and pure Cu(111) surfaces have been obtained. Their computed adsorption energy results on the pure Cu(111) surface have been compared with the previously reported studies. Then, transition state geometries of CH4 dehydrogenation steps on both surfaces were calculated by the climbing image nudged elastic band method. Finally, the relative energy diagram for CH4 complete dehydrogenation has been represented. The results show that the PdCu(111) surface is more favorable than the Cu(111) surface in terms of the activation energies. The addition of Pd atoms to the Cu(111) surface significantly improves the catalytic activity. This knowledge can enable an efficient catalyst design at a lower cost using different strategies.

Searching for Saddle Points by Using the Nudged Elastic Band Method:  An Implementation for Gas-Phase Systems

2006 ◽  
Vol 2 (4) ◽  
pp. 895-904 ◽  
Author(s):  
Núria González-García ◽  
Jingzhi Pu ◽  
Àngels González-Lafont ◽  
José M. Lluch ◽  
Donald G. Truhlar
Keyword(s):  
Gas Phase ◽  
Saddle Points ◽  
Elastic Band ◽  
Band Method ◽  
Phase Systems

scholarly journals MULTIBREATHER AND VORTEX BREATHER STABILITY IN KLEIN–GORDON LATTICES: EQUIVALENCE BETWEEN TWO DIFFERENT APPROACHES

2011 ◽  
Vol 21 (08) ◽  
pp. 2161-2177 ◽  
Author(s):  
J. CUEVAS ◽  
V. KOUKOULOYANNIS ◽  
P. G. KEVREKIDIS ◽  
J. F. R. ARCHILLA
Keyword(s):  
Coupled Oscillators ◽  
Hamiltonian Method ◽  
Band Theory ◽  
Floquet Multipliers ◽  
One Dimensional ◽  
Case Examples ◽  
Discrete Breathers ◽  
Klein Gordon ◽  
Band Method ◽  
Time Periodic

In this work, we revisit the question of stability of multibreather configurations, i.e. discrete breathers with multiple excited sites at the anti-continuum limit of uncoupled oscillators. We present two methods that yield quantitative predictions about the Floquet multipliers of the linear stability analysis around such exponentially localized in space, time-periodic orbits, based on the Aubry band method and the MacKay effective Hamiltonian method, and prove that by making the suitable assumptions about the form of the bands in the Aubry band theory, their conclusions are equivalent. Subsequently, we showcase the usefulness of the methods through a series of case examples including one-dimensional multi-breathers, and two-dimensional vortex breathers in the case of a lattice of linearly coupled oscillators with the Morse potential and in that of the discrete ϕ4 model.

Preservice and Experienced Teachers' Lesson Plans for Beginning Instrumentalists

2005 ◽  
Vol 53 (1) ◽  
pp. 26-39 ◽  
Author(s):  
Ruth V. Brittin
Keyword(s):  
Lesson Plan ◽  
Lesson Plans ◽  
Level Of Detail ◽  
Experienced Teachers ◽  
Word Count ◽  
Beginning Band ◽  
Method Book ◽  
Beginning Instrumentalists ◽  
Institutional Differences ◽  
Band Method

Preservice and experienced teachers ( N=58, from 7 universities) wrote lesson plans for a hypothetical beginning band lesson, using one page from a band method book as source material. Lesson plans were analyzed for word count, level of detail, and for strategies that appeared most frequently. Experienced teachers used fewer words than undergraduates but revealed the same number of strategies and level of detail, on average. There were institutional differences in the variety of strategies incorporated, indicating certain institutions may value a wider range of strategies and activities in beginning band classes. Participants also compared their written plans to a published lesson plan and rated their familiarity with various approaches, giving another view on strategies considered most common. Familiarity ratings were similar when comparing preservice and experienced teachers and when comparing institutions. Degrees of prevalence of specific strategies, such as decontextualization of material, repetition, and modeling are discussed. May 7, 2004 January 18, 2005.

scholarly journals Level set band method: A combination of density-based and level set methods for the topology optimization of continuums

2020 ◽  
Vol 15 (3) ◽  
pp. 390-405
Author(s):  
Peng Wei ◽  
Wenwen Wang ◽  
Yang Yang ◽  
Michael Yu Wang
Keyword(s):  
Topology Optimization ◽  
Level Set ◽  
Level Set Methods ◽  
Boundary Representation ◽  
Structural Topology ◽  
Topology Changes ◽  
Practical Engineering ◽  
Band Method ◽  
2D And 3D ◽  
Level Set Framework

Abstract The level set method (LSM), which is transplanted from the computer graphics field, has been successfully introduced into the structural topology optimization field for about two decades, but it still has not been widely applied to practical engineering problems as density-based methods do. One of the reasons is that it acts as a boundary evolution algorithm, which is not as flexible as density-based methods at controlling topology changes. In this study, a level set band method is proposed to overcome this drawback in handling topology changes in the level set framework. This scheme is proposed to improve the continuity of objective and constraint functions by incorporating one parameter, namely, level set band, to seamlessly combine LSM and density-based method to utilize their advantages. The proposed method demonstrates a flexible topology change by applying a certain size of the level set band and can converge to a clear boundary representation methodology. The method is easy to implement for improving existing LSMs and does not require the introduction of penalization or filtering factors that are prone to numerical issues. Several 2D and 3D numerical examples of compliance minimization problems are studied to illustrate the effects of the proposed method.

scholarly journals Revisiting the Volmer–Heyrovský mechanism of hydrogen evolution on a nitrogen doped carbon nanotube: constrained molecular dynamics versus the nudged elastic band method

2020 ◽  
Vol 22 (19) ◽  
pp. 10536-10549 ◽  
Author(s):  
Rasmus Kronberg ◽  
Heikki Lappalainen ◽  
Kari Laasonen
Keyword(s):  
Hydrogen Evolution ◽  
Electrochemical Reactions ◽  
Direct Simulation ◽  
Elastic Band ◽  
Nitrogen Doped ◽  
Solvent Dynamics ◽  
Rigorous Description ◽  
Band Method ◽  
Nitrogen Doped Carbon ◽  
Explicit Dynamic

This study presents the first direct simulation of the hydrogen evolution reaction using a fully explicit, dynamic DFT approach and highlights the importance of incorporating solvent dynamics in the rigorous description of electrochemical reactions.

Defect Detection on Patterned Fabrics Using Distance Matching Function and Regular Band

2015 ◽  
Vol 10 (2) ◽  
pp. 155892501501000
Author(s):  
Junfeng Jing ◽  
Panpan Yang ◽  
Pengfei Li
Keyword(s):  
Defect Detection ◽  
Matching Function ◽  
Regular Band ◽  
Fabric Defect ◽  
Band Method ◽  
Performance Ability

In this paper, regular band is presented to detect defects on patterned fabrics. Patterned fabrics are firstly disposed by fabric average to form object images mixed with positive and negative pixels in this proposed method. Distance matching function is computed to determine the periodic distance of patterned fabrics. The obtained periodic distance would be the length and width of regular band on row and column. Two features are calculated with regular band. The threshold of defect segmentation is extracted from the training step. Two features of regular band negotiating the threshold are considered as a fabric defect. Regular band method in this paper can avoid patterned interference and obtain perfect results in defect detection of patterned fabrics. Various defects on patterned fabrics can be inspected, and speedy defect detection could prove the performance ability in practice.

Atomic-Scale Modeling of the Annihilation of Jogged Screw Dislocation Dipoles

1999 ◽  
Vol 578 ◽  
Author(s):  
T. Vegge ◽  
O. B. Pedersen ◽  
T. Leffers ◽  
K. W. Jacobsen
Keyword(s):  
Molecular Dynamics ◽  
Screw Dislocation ◽  
Atomic Scale ◽  
Atomistic Simulations ◽  
Elastic Band ◽  
Screw Dislocations ◽  
Scale Modeling ◽  
Band Method

AbstractUsing atomistic simulations we investigate the annihilation of screw dislocation dipoles in Cu. In particular we determine the influence of jogs on the annihilation barrier for screw dislocation dipoles. The simulations involve energy minimizations, molecular dynamics, and the Nudged Elastic Band method. We find that jogs on screw dislocations substantially reduce the annihilation barrier, hence leading to an increase in the minimum stable dipole height.

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