scholarly journals Microstructure of the fluid particles around the rigid body at the shear-thickening state toward understanding of the fluid mechanics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryota Jono ◽  
Syogo Tejima ◽  
Jun-ichi Fujita
Keyword(s):  
Shear Thickening ◽  
Rigid Bodies ◽  
Distribution Functions ◽  
Anisotropic Structures ◽  
Thickening Behavior ◽  
Fluid Particles ◽  
The Difference ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Pair Distribution Functions

AbstractWe studied the shear-thickening behavior of systems containing rigid spherical bodies immersed in smaller particles using non-equilibrium molecular dynamics simulations. We generated shear-thickening states through particle mass modulation of the systems. From the microstructures, i.e., two-dimensional pair distribution functions, we found anisotropic structures resulting from shear thickening, that are explained by the difference between the velocities of rigid bodies and fluid particles. The increasing viscosity in our system originated from collisions between fluid particles and rigid bodies. The lubrication forces defined in macroscale physics are then briefly discussed.

scholarly journals Local structure and distortions of mixed methane-carbon dioxide hydrates

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Bernadette R. Cladek ◽  
S. Michelle Everett ◽  
Marshall T. McDonnell ◽  
Matthew G. Tucker ◽  
David J. Keffer ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Exchange Process ◽  
Carbon Dioxide Sequestration ◽  
Distribution Functions ◽  
Atomic Scale ◽  
Mixed Gas ◽  
Pure Compounds ◽  
Dynamics Simulations ◽  
Pair Distribution Functions ◽  
Methane Carbon

AbstractA vast source of methane is found in gas hydrate deposits, which form naturally dispersed throughout ocean sediments and arctic permafrost. Methane may be obtained from hydrates by exchange with hydrocarbon byproduct carbon dioxide. It is imperative for the development of safe methane extraction and carbon dioxide sequestration to understand how methane and carbon dioxide co-occupy the same hydrate structure. Pair distribution functions (PDFs) provide atomic-scale structural insight into intermolecular interactions in methane and carbon dioxide hydrates. We present experimental neutron PDFs of methane, carbon dioxide and mixed methane-carbon dioxide hydrates at 10 K analyzed with complementing classical molecular dynamics simulations and Reverse Monte Carlo fitting. Mixed hydrate, which forms during the exchange process, is more locally disordered than methane or carbon dioxide hydrates. The behavior of mixed gas species cannot be interpolated from properties of pure compounds, and PDF measurements provide important understanding of how the guest composition impacts overall order in the hydrate structure.

Imaging of interstitial atoms in Ga1−xMnxAs layers by means of X-ray diffuse scattering

2008 ◽  
Vol 41 (3) ◽  
pp. 544-547 ◽  
Author(s):  
Miloš Kopecký ◽  
Edoardo Busetto ◽  
Andrea Lausi ◽  
Zbyněk Šourek ◽  
Jiří Kub ◽  
...  
Keyword(s):  
Atomic Structure ◽  
Diffuse Scattering ◽  
Annealing Process ◽  
Distribution Functions ◽  
Unit Cell ◽  
X Ray ◽  
Interstitial Atoms ◽  
Before And After ◽  
The Difference ◽  
Pair Distribution Functions

The local atomic structure of a Ga1−xMnxAs (x= 0.07) layer during the annealing process was studied by means of X-ray diffuse scattering. The difference between the pair-distribution functions before and after annealing indicated the fraction of atoms that changed concentration and identified them to be exclusively interstitial atoms at the centres of gallium and/or arsenic tetrahedra in the GaMnAs unit cell.

Simulating Structural Transformation of a Cu1553 Nanoparticle on Heating at Atomic Scale

2015 ◽  
Vol 817 ◽  
pp. 736-739
Author(s):  
Jing Zhang ◽  
Peng Yu
Keyword(s):  
Structural Transformation ◽  
Structural Changes ◽  
Distribution Functions ◽  
Atomic Scale ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Different Temperatures ◽  
Dynamics Simulations ◽  
Pair Distribution Functions ◽  
Pair Analysis

By means of molecular dynamics simulations within the framework of embedded atom method, we observe the structural transformation of a Cu nanoparticle containing 1553 atoms at atomic scale on a heating series from 350K to 1200K at an increment of 50K. With increasing the temperature, the structural changes result in apparent increases in internal energy. Pair distribution functions (PDFs) and pair analysis (PA) technique as well as the atom packing at different temperatures are used to identify the local structural patterns during the melting of this particle.

Molecular dynamics simulations of EPON-862/DETDA epoxy networks: structure, topology, elastic constants, and local dynamics

Soft Matter ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 721-733 ◽  
Author(s):  
Spyros V. Kallivokas ◽  
Aristotelis P. Sgouros ◽  
Doros N. Theodorou
Keyword(s):  
Molecular Dynamics ◽  
Elastic Constants ◽  
Distribution Functions ◽  
Glass Temperature ◽  
Segmental Dynamics ◽  
Structure Topology ◽  
Xrd Patterns ◽  
Dynamics Simulations ◽  
Networks Structure ◽  
Pair Distribution Functions

Partial pair distribution functions, XRD patterns, segmental dynamics, elastic constants and glass temperature in EPON862/DETDA epoxy predicted through molecular dynamics.

Pressure Induced Structural Transformations in Nanocluster Assembled Gallium Arsenide

1998 ◽  
Vol 536 ◽  
Author(s):  
S. Kodiyalam ◽  
A. Chatterjee ◽  
I. Ebbsjö ◽  
R. K. Kalia ◽  
H. Kikuchi ◽  
...  
Keyword(s):  
Bond Angle ◽  
Structural Phase ◽  
High Stress ◽  
Distribution Functions ◽  
Structural Phase Transformation ◽  
Spatially Resolved ◽  
Parallel Molecular Dynamics ◽  
Dynamics Simulations ◽  
Pair Distribution Functions ◽  
Single Cluster

AbstractPressure induced structural phase transformation in nanocluster assembled GaAs is studied using parallel molecular dynamics simulations in the isothermal-isobaric ensemble. In this system the spatial stress distribution is found to be inhomogeneous. As a result structural transformation initiates in the high stress regions at the interface between clusters. Structural and dynamical correlations in the nanophase system are characterized by calculating the spatially resolved bond angle and pair distribution functions and phonon density of states and comparing them with those for a single cluster and bulk crystalline and amorphous systems.

Structure, Fragmentation, and Phonons in Silicon Microclusters

1992 ◽  
Vol 293 ◽  
Author(s):  
Wei Li ◽  
Rajiv K. Kalia ◽  
Priya Vashishta
Keyword(s):  
Molecular Dynamics ◽  
Structural Information ◽  
Magic Number ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Silicon Clusters ◽  
Atom Clusters ◽  
Densities Of States ◽  
Dynamics Simulations ◽  
Pair Distribution Functions

AbstractMolecular-dynamics simulations are performed to investigate structures, vibrational spectra, and fragmentation channels of silicon microclusters ranging in size from 32 to 52 atoms. Structural information is derived from pair-distribution functions, bond-angle distributions, and the structure and statistics of rings. Molecular-dynamics simulation results for energetics suggest that 33, 39, 45 and 51 atom clusters are highly stable. These magic-number clusters have predominantly five and six membered rings. With an increase in “temperature”, most clusters tend to fragment by loosing one atom at a time. Vibrational densities of states of 32-52 atom silicon clusters show only minor deviations from the bulk behavior.

AB INITIO MOLECULAR DYNAMICS STUDY OF DISSOLVED SiO2 IN SUPERCRITICAL WATER

2007 ◽  
Vol 06 (01) ◽  
pp. 49-62 ◽  
Author(s):  
N. L. DOLTSINIS ◽  
M. BURCHARD ◽  
W. V. MARESCH ◽  
A. D. BOESE ◽  
T. FOCKENBERG
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Supercritical Water ◽  
Statistical Error ◽  
Distribution Functions ◽  
Time Span ◽  
Ab Initio Molecular Dynamics ◽  
Spontaneous Polymerization ◽  
Dynamics Simulations ◽  
Pair Distribution Functions

Ab initio molecular dynamics simulations of SiO 2 in supercritical water at temperatures of 900 K and 1200 K and a pressure of 1.5 GPa at concentrations of 5 wt% and 16 wt% have been carried out. The different polymeric forms SiO 4 H 4, Si 2 O 7 H 6, and Si 3 O 10 H 8 are found to be energetically similar within the statistical error, suggesting that all three polymeric forms play an important role in solutions at the above conditions. However, neither spontaneous polymerization nor depolymerization has been observed during the 10-ps time span of the simulations. The dynamic and structural properties of the supercritical solutions have been analyzed in terms of diffusion coefficients, vibrational spectra, and radial pair distribution functions.

Comparison of the Structure of Liquid Amides as Determined by Diffraction Experiments and Molecular Dynamics Simulations

1995 ◽  
Vol 50 (1) ◽  
pp. 38-50 ◽  
Author(s):  
Pia C. Schoester ◽  
Manfred D. Zeidler ◽  
Tamäs Radnai ◽  
Philippe A. Bopp
Keyword(s):  
Molecular Dynamics ◽  
Room Temperature ◽  
Heavy Atom ◽  
Distribution Functions ◽  
X Ray ◽  
Atom Pairs ◽  
Dynamics Simulations ◽  
Pair Distribution Functions ◽  
Flexible Models ◽  
Site Pair

The intermodular structures of liquid formamide, N-methylformamide and N,N-dimethylformamide at room temperature are studied by means of NVE molecular dynamics computer simulations. Newly developed flexible models are used. X-ray and neutron weighted structure and total radial pair distribution functions are computed from the simulated site-site pair distribution functions. They are compared with experimental results. The agreement is usually satisfactory as far as heavy atom pairs are concerned while the lengths of the hydrogen bonds are found to be systematically too long in the simulations.

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