scholarly journals The drag effect of air bubbles on triple junction migration of pure ice

2021 ◽  
Vol 11 (1) ◽  
pp. 86-97
Author(s):  
Pastor Ignacio Achával ◽  
Carlos Leonardo Di Prinzio
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Grain Boundary ◽  
Numerical Simulations ◽  
Triple Junction ◽  
Optical Microscope ◽  
Air Bubbles ◽  
Drag Effect ◽  
Junction Geometry

The migration of a grain triple junction was studied on ice pure samples with bubbles at -2°C for almost 3 h. This work studies the interaction between Grain Boundary (GB) and bubbles. The evolution of the triple junction was recorded from successive photographs obtained from a LEICA® optical microscope. Simultaneously, numerical simulations of grain triple junction with mobile bubbles were carried out using Monte Carlo method with the following conditions: The bubbles in the bulk were kept immobile and those in the GB were allowed to move. In addition, mobile bubbles were forced to stay inside the GB. The simulations show that bubbles slow down the movement of the GB and of the triple junction. What’s more, the simulated triple junction obtained fits very well the experimental triple junction geometry, and the GB diffusivity values obtained coincide with those measured experimentally at the same temperature and reported by other authors. Finally, the drag effect of the mobile bubbles on the GB migration was verified.

STUDY OF THE GRAIN BOUNDARY MIGRATION IN A TRICRISTAL PURE ICE WITH BUBBLES

Anales AFA ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 47-51
Author(s):  
P.I. Achával ◽  
C. L. Di Prinzio
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Numerical Simulations ◽  
Triple Junction ◽  
Boundary Migration ◽  
Optical Microscope ◽  
Physical Parameters ◽  
Grain Boundary Migration

In this paper the migration of a grain triple junction in apure ice sample with bubbles at -5°C was studied for almost 3hs. This allowed tracking the progress of the Grain Boundary (BG) and its interaction with the bubbles. The evolution of the grain triple junction was recorded from successive photographs obtained witha LEICA® optical microscope. Simultaneously, numerical simulations were carried out using Monte Carlo to obtain some physical parameters characteristic of the BG migration on ice.

scholarly journals GRAIN BOUNDARY MIGRATION IN THIN FILMS USING MONTE CARLO METHOD

Anales AFA ◽  
2020 ◽  
Vol 31 (1) ◽  
pp. 7-12
Author(s):  
C. L. Di Prinzio ◽  
P. I. Achával ◽  
D. Stoler ◽  
G. Aguirre Varela
Keyword(s):  
Thin Films ◽  
Monte Carlo ◽  
Free Surface ◽  
Monte Carlo Method ◽  
Grain Boundary ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
Thin Sample ◽  
The Monte Carlo Method ◽  
Theoretical Results

This paper presents the evolution of a flat grain boundary in a thin sample, using a numerical algorithm based on the Monte Carlo method. The grain boundary is driven by an external force and the effect of the free surface is studied.The grain boundary migration on the free surface is spasmodic, which means that it has alternating periods of movement and stagnation. Stagnation periods are inversely proportional to the thickness of the sample. The results obtained computationally fitted acceptable with the theoretical results obtained by different authors.

Extraction of Grain Boundary Energies from Triple Junction Geometry

1999 ◽  
Vol 5 (S2) ◽  
pp. 230-231
Author(s):  
A. D. Rollett ◽  
C.-C. Yang ◽  
W. W. Mullins ◽  
B. L. Adams ◽  
C. T. Wu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Triple Junction ◽  
Preliminary Analysis ◽  
Boundary Energy ◽  
Orientation Imaging Microscopy ◽  
Dihedral Angles ◽  
Grain Boundary Energy ◽  
Boundary Character ◽  
Junction Geometry

Measurement of the geometry of triple junctions between grain boundaries in polycrystalline materials is used to generate large sets of dihedral angles from which maps of the grain boundary energy are extracted. A preliminary analysis has been performed for samples of magnesia and aluminum based on a three-parameter description of grain boundaries. An extended form of orientation imaging microscopy (OIM) was used to measure both triple junction geometry via image analysis in the SEM and local grain orientation via electron back scatter diffraction. Serial sectioning with registry of both in-plane images and successive sections characterizes triple junction tangents from which true dihedral angles are calculated. If there is local equilibrium at each triple junction, we may apply Herring's relation. By limiting grain boundary character to a (three parameter) specification of misorientation for the preliminary analysis, we can neglect the torque terms and apply the sine law to the three boundaries. This provides two independent relations per triple junction between grain boundary energies and dihedral angles. By discretizing the misorientation and employing multiscale statistical analysis on large data sets, (relative) grain boundary energy as a function of boundary character can be extracted from triple junction geometry. The results are discussed with respect to current understanding of grain boundary structure based on their crystallography. The results suggest that a three parameter characterization of grain boundaries (lattice disorientation) is not an adequate description of boundary character. A full analysis including torque terms and a five parameter boundary description is under development.

scholarly journals Dilution of Ferromagnets via a Random Graph-Based Strategy

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Marco Alberto Javarone ◽  
Daniele Marinazzo
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Numerical Simulations ◽  
Random Graphs ◽  
Complete Graph ◽  
Statistical Physics ◽  
Graph Model ◽  
One Step ◽  
Great Relevance ◽  
And Behavior

The dynamics and behavior of ferromagnets have a great relevance even beyond the domain of statistical physics. In this work, we propose a Monte Carlo method, based on random graphs, for modeling their dilution. In particular, we focus on ferromagnets with dimension D≥4, which can be approximated by the Curie-Weiss model. Since the latter has as graphic counterpart, a complete graph, a dilution can be in this case viewed as a pruning process. Hence, in order to exploit this mapping, the proposed strategy uses a modified version of the Erdős-Renyi graph model. In doing so, we are able both to simulate a continuous dilution and to realize diluted ferromagnets in one step. The proposed strategy is studied by means of numerical simulations, aiming to analyze main properties and equilibria of the resulting diluted ferromagnets. To conclude, we also provide a brief description of further applications of our strategy in the field of complex networks.

Multiphase microstructure evolution model including dislocation plasticity

2002 ◽  
Vol 17 (8) ◽  
pp. 1932-1940 ◽  
Author(s):  
Fabrizio Cleri ◽  
Gregorio D'Agostino
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Numerical Simulations ◽  
Microstructure Evolution ◽  
Evolution Model ◽  
Monte Carlo Algorithm ◽  
Two Dimensional ◽  
Triple Junctions ◽  
Multiphase Microstructure ◽  
Dislocation Plasticity

We present the recent extensions of our stochastic microstructure evolution model including multiphase domain evolution and dislocation plasticity. The model was implemented by means of numerical simulations based on the velocity Monte Carlo algorithm. It describes the evolution of a two-dimensional microstructure by tracking the motion of triple junctions, i.e., the vertices where three grain boundaries (GBs) meet. GBs can be modeled as straight, curved, or discretized segments; the misorientation dependence of both grain-boundary energies and mobilities can be included to represent different textures.

Outbursts of comet Schwassmann-Wachmann 1, and the cloud of interplanetary boulders

1974 ◽  
Vol 22 ◽  
pp. 307 ◽  
Author(s):  
Zdenek Sekanina
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Interplanetary Space ◽  
Porous Matrix ◽  
Maximum Diameter ◽  
Expansion Velocity ◽  
Solid Constituent ◽  
Meteoric Material ◽  
Periodic Comet

AbstractIt is suggested that the outbursts of Periodic Comet Schwassmann-Wachmann 1 are triggered by impacts of interplanetary boulders on the surface of the comet’s nucleus. The existence of a cloud of such boulders in interplanetary space was predicted by Harwit (1967). We have used the hypothesis to calculate the characteristics of the outbursts – such as their mean rate, optically important dimensions of ejected debris, expansion velocity of the ejecta, maximum diameter of the expanding cloud before it fades out, and the magnitude of the accompanying orbital impulse – and found them reasonably consistent with observations, if the solid constituent of the comet is assumed in the form of a porous matrix of lowstrength meteoric material. A Monte Carlo method was applied to simulate the distributions of impacts, their directions and impact velocities.

Structures and crystallization of vacuum-deposited amorphous Se and Sb films

1990 ◽  
Vol 48 (4) ◽  
pp. 140-141
Author(s):  
Makoto Shiojiri ◽  
Toshiyuki Isshiki ◽  
Tetsuya Fudaba ◽  
Yoshihiro Hirota
Keyword(s):  
Monte Carlo ◽  
Electron Microscope ◽  
Monte Carlo Method ◽  
Computer Program ◽  
Radial Distribution ◽  
Film Formation ◽  
Amorphous State ◽  
Two Dimensional ◽  
Amorphous Films ◽  
Binding Condition

In hexagonal Se crystal each atom is covalently bound to two others to form an endless spiral chain, and in Sb crystal each atom to three others to form an extended puckered sheet. Such chains and sheets may be regarded as one- and two- dimensional molecules, respectively. In this paper we investigate the structures in amorphous state of these elements and the crystallization.HRTEM and ED images of vacuum-deposited amorphous Se and Sb films were taken with a JEM-200CX electron microscope (Cs=1.2 mm). The structure models of amorphous films were constructed on a computer by Monte Carlo method. Generated atoms were subsequently deposited on a space of 2 nm×2 nm as they fulfiled the binding condition, to form a film 5 nm thick (Fig. 1a-1c). An improvement on a previous computer program has been made as to realize the actual film formation. Radial distribution fuction (RDF) curves, ED intensities and HRTEM images for the constructed structure models were calculated, and compared with the observed ones.

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