scholarly journals An Overview of Recent Standard and Accelerated Molecular Dynamics Simulations of Helium Behavior in Tungsten

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2500 ◽  
Author(s):  
Luis Sandoval ◽  
Danny Perez ◽  
Blas P. Uberuaga ◽  
Arthur F. Voter
Keyword(s):  
Molecular Dynamics ◽  
Nucleation And Growth ◽  
High Melting ◽  
High Melting Point ◽  
Fusion Power ◽  
Helium Bubbles ◽  
Accelerated Molecular Dynamics ◽  
Plasma Facing Materials ◽  
Sputtering Yield ◽  
Dynamics Simulations

One of the most critical challenges for the successful adoption of nuclear fusion power corresponds to plasma-facing materials. Due to its favorable properties in this context (low sputtering yield, high thermal conductivity, high melting point, among others), tungsten is a leading candidate material. Nevertheless, tungsten is affected by the plasma and fusion byproducts. Irradiation by helium nuclei, in particular, strongly modifies the surface structure by a synergy of processes, whose origin is the nucleation and growth of helium bubbles. In this review, we present recent advances in the understanding of helium effects in tungsten from a simulational approach based on accelerated molecular dynamics, which emphasizes the use of realistic parameters, as are expected in experimental and operational fusion power conditions.

scholarly journals Molecular Dynamics Simulations of Crystal Nucleation near Interfaces in Incompatible Polymer Blends

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou
Keyword(s):  
Molecular Dynamics ◽  
Polymer Blends ◽  
Md Simulations ◽  
Nucleation And Growth ◽  
Crystal Nucleation ◽  
Crystalline Order ◽  
Mobile Species ◽  
Deep Supercooling ◽  
Crystallizable Polymer ◽  
Dynamics Simulations

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.

Study of the nucleation and growth of TiO2 and ZnO thin films by means of molecular dynamics simulations

2009 ◽  
Vol 311 (16) ◽  
pp. 4034-4043 ◽  
Author(s):  
Neyda Baguer ◽  
Violeta Georgieva ◽  
Lazaro Calderin ◽  
Ilian T. Todorov ◽  
Sake Van Gils ◽  
...  
Keyword(s):  
Thin Films ◽  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Nucleation And Growth ◽  
Zno Thin Films ◽  
Dynamics Simulations

scholarly journals Accelerated Molecular Dynamics Applied to the Peptaibol Folding Problem

2019 ◽  
Vol 20 (17) ◽  
pp. 4268
Author(s):  
Chetna Tyagi ◽  
Tamás Marik ◽  
Csaba Vágvölgyi ◽  
László Kredics ◽  
Ferenc Ötvös
Keyword(s):  
Molecular Dynamics ◽  
Enhanced Sampling ◽  
New Approach ◽  
E Coli ◽  
Accelerated Molecular Dynamics ◽  
Simulation Techniques ◽  
Unfolded State ◽  
Folding Dynamics ◽  
Transmembrane Channels ◽  
Dynamics Simulations

The use of enhanced sampling molecular dynamics simulations to facilitate the folding of proteins is a relatively new approach which has quickly gained momentum in recent years. Accelerated molecular dynamics (aMD) can elucidate the dynamic path from the unfolded state to the near-native state, “flattened” by introducing a non-negative boost to the potential. Alamethicin F30/3 (Alm F30/3), chosen in this study, belongs to the class of peptaibols that are 7–20 residue long, non-ribosomally synthesized, amphipathic molecules that show interesting membrane perturbing activity. The recent studies undertaken on the Alm molecules and their transmembrane channels have been reviewed. Three consecutive simulations of ~900 ns each were carried out where N-terminal folding could be observed within the first 100 ns, while C-terminal folding could only be achieved almost after 800 ns. It took ~1 μs to attain the near-native conformation with stronger potential boost which may take several μs worth of classical MD to produce the same results. The Alm F30/3 hexamer channel was also simulated in an E. coli mimicking membrane under an external electric field that correlates with previous experiments. It can be concluded that aMD simulation techniques are suited to elucidate peptaibol structures and to understand their folding dynamics.

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