scholarly journals Molecular-scale thermally activated fractures in methane hydrates: a molecular dynamics study

2019 ◽  
Vol 21 (25) ◽  
pp. 13539-13544 ◽  
Author(s):  
Henrik Andersen Sveinsson ◽  
Anders Malthe-Sørenssen

Cage by cage slow fracture initiation in methane hydrates is consistent with a thermal activation model.

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3264
Author(s):  
Vladik A. Avetisov ◽  
Maria A. Frolkina ◽  
Anastasia A. Markina ◽  
Alexander D. Muratov ◽  
Vladislav S. Petrovskii

The intensive development of nanodevices acting as two-state systems has motivated the search for nanoscale molecular structures whose dynamics are similar to those of bistable mechanical systems, such as Euler arches and Duffing oscillators. Of particular interest are the molecular structures capable of spontaneous vibrations and stochastic resonance. Recently, oligomeric molecules that were a few nanometers in size and exhibited the bistable dynamics of an Euler arch were identified through molecular dynamics simulations of short fragments of thermo-responsive polymers subject to force loading. In this article, we present molecular dynamics simulations of short pyridine-furan springs a few nanometers in size and demonstrated the bistable dynamics of a Duffing oscillator with thermally-activated spontaneous vibrations and stochastic resonance.


2008 ◽  
Vol 120 (44) ◽  
pp. 8615-8619 ◽  
Author(s):  
Fabrice Salles ◽  
Aziz Ghoufi ◽  
Guillaume Maurin ◽  
Robert G. Bell ◽  
Caroline Mellot-Draznieks ◽  
...  

2019 ◽  
Vol 806 ◽  
pp. 100-105 ◽  
Author(s):  
Yury M. Nikolenko ◽  
Alexander K. Tsvetnikov ◽  
Alexander Yu. Ustinov ◽  
Vladimir E. Silant'ev ◽  
Valery G. Kuryavyi ◽  
...  

The hydrolytic lignin (HL) derivatives have been prepared via its physical activation (high-temperature annealing in vacuum) followed by chemical modification (fluorination). It was found that the graphitized product of thermal activation up to 1000 °C at a low temperature gain rate of < 2 °C/min under high vacuum shows an enhanced specific surface area (215 m2/g), that makes it potentially useful as sorbent, catalytic substrate, or electrode material. It was revealed from the experimental data the manufactured graphitized material consists of nanometric structural blocks, possibly nanographites and/or few-layer nanographenes. The edges of graphenes in agglomerates in activated hydrolytic lignin (AHL) have armchair and zigzag shapes. The nontrivial electronic structure of the zigzag edges, along with the electronic conductivity and the ability of AHL to absorb oxygen, can cause an increase in the energy intensity of lithium battery (LB) manufactured using AHL.The carbon-fluorine bond of semi-ionic type was detected in HL and AHL fluorinated in the temperature range of synthesize 60 – 300 oC. The fluorinated forms of both HL and its thermally activated product show increased values of operating voltage due to the participation of fluorine bound to carbon in the electrochemical process.


2015 ◽  
Vol 17 (36) ◽  
pp. 23356-23367 ◽  
Author(s):  
A. Ozgur Yazaydin ◽  
Geoffrey M. Bowers ◽  
R. James Kirkpatrick

Molecular dynamics modeling of systems containing a Na-exchanged hectorite and model natural organic matter molecules along with pure H2O, pure CO2, or a mixture of H2O and CO2 provides significant new insight into the molecular scale interactions among silicate surfaces, dissolved cations and organic molecules, H2O and CO2.


2001 ◽  
Vol 683 ◽  
Author(s):  
Masato Hiratani ◽  
Hussein M. Zbib

ABSTRACTThermally activated dislocation glide velocity through weak point obstacle arrays is studied analytically and computationally. Thermal activation rate is estimated using the modified Friedel relations under the weak obstacle approximation. The average flight velocity after an activation event as a function of stress and temperature is obtained by the discrete dislocation dynamics (DD). This numerical calculation includes the effect of self-stress, interaction with electrons and phonons, and the inertial effect. These results are implemented into a phenomenological model to study the dislocation velocity under various conditions. The model can reproduce both obstacle control and drag control motion in low and high velocity regions, and a flow stress anomaly at transient regions.


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