Topological structure of density fluctuations in condensed matter

Kolokol, A. S.; Shimkevich, Alexander L.

doi:10.1016/j.jnoncrysol.2009.11.020

Cited by 8 publications

(10 citation statements)

References 8 publications

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“…Indeed, a structural state of additive particle in the liquid matrix has a dual character due to density fluctuations of liquid alloy [16,17]. At low mole fraction, additive atoms settle outside the dense part of liquid alloy, i.e.…”

Section: Polymorphic Converting the Liquid Metal Structurementioning

confidence: 99%

Eutectic Na–Tl and Pb–Mg alloys as liquid-metal coolants for fast nuclear reactors

Alekseev¹,

Shimkevich²,

Shimkevich³

2015

Computational Methods and Experimental Measurements XVII

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The liquid-metal microstructure is a correct subdivision of Delaunay simplexes (triangular pyramids with atoms in their vertexes). Its dense part consists of almost regular tetrahedrons connected by faces in ramified clusters. Any metal additive (as a second component of alloy) can be outside of these tetrahedral clusters or into them as a constituent of dense liquid part. These structural states of liquid alloy convert to each other at its eutectic composition. Such the polymorphic conversion of the liquid-metal alloy is approved by moleculardynamics simulating the Pb-K alloy and can be applied to any eutectic, for example, Na0.93Tl0.07 with the melting point of 64 C. At the sodium side of this point, a homogeneous solution of thallium is formed in liquid sodium which becomes the colloidal one with clusters, (Na 6 Tl) n , when it is passing the eutectic point. Such the modified sodium coolant enriched by the isotope, 205 Tl, can appear attractive for inhibiting the chemical activity of this coolant maintained by oxygen-free technology. An alternative liquid-metal coolant for fast nuclear reactors is eutectic, Pb 0.83 Mg 0.17 , with the melting point of 248 C. This liquid alloy as a modified lead coolant maintained by the same oxygen-free technology can appear attractive for inhibiting the high corrosion activity of molten lead.

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Section: Polymorphic Converting the Liquid Metal Structurementioning

confidence: 99%

Eutectic Na–Tl and Pb–Mg alloys as liquid-metal coolants for fast nuclear reactors

Alekseev¹,

Shimkevich²,

Shimkevich³

2015

Computational Methods and Experimental Measurements XVII

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“…On the other hand, impurity atoms (at a low concentration) are placed on the external faces of tetrahedral clusters of the dense liquid part not changing its microstructure, that is forming the introduction solution [14,16]. In increasing the concentration, the impurity adds its tetrahedral clusters to the dense part of the basic liquid, so that the solution becomes nonhomogeneous in addition of the solution [17].…”

Section: Possible States Of Impurities In Liquidsmentioning

confidence: 99%

“…They consist of almost regular tetrahedrons connected in pairs by faces in ramified chains [15,16]. Impurity atoms can be placed on the external faces of these chains not changing the microstructure of the dense liquid part forming an "introduction" solution [14,16].…”

Section: Introductionmentioning

confidence: 99%

On Clustering Impurities by Liquid Density Fluctuations

Shimkevich

2010

Physics Research International

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Recent developments in liquid technology have created a new class of fluids called "nanofluids" which are two-phase mixtures of a non-metal-liquid matrix and addon particles usually less than 100 nm in size. It is reputed that such liquids have a great potential for application. Indeed, many tests have shown that their thermal conductivity can be increased by almost 20% compared to that of the base fluids for a relatively low particle loading (of 1 up to 5% in volume). It is confirmed by experimental data and simulation results. In this study, the author considers an effect of impurity clustering by liquid density fluctuations as a natural mechanism for stabilizing microstructure of the colloidal solution and estimates the effect of fractal structure of colloidal particles on thermal conductivity of water. The results of this study may be useful for motivating choosing the composition of heat-transfer suspension and developing technology for making the appropriate nanofluid.

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“…Using the topological criterion [3] in molecular-dynamic (MD) simulation of deterministic nonlinear system of many particles, one can exactly select these simplexes by defining a maximal length of their edges over the maximal number of obtained simplex clusters in the MD cell. The statistics of these clusters is gotten for any condensed matter [4] as their twodimensional (2D) discrete distribution on cardinality (number of simplexes in the cluster) and on connectivity (number of their vertexes belonging also to other clusters).…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the cardinality of dense-part clusters in any crystal is equal to 1, while amorphous solid occupies the intermediate position between crystal and liquid on the discrete 2D distribution of dense-part clusters [4]. At the same time, the tetrahedral clusters of dense-part open for impurity in principle two topologically differing positions in liquid and amorphous solid: (1) outside the dense-part simplexes and (2) in their clusters as compound constituents [6,7].…”

Section: Introductionmentioning

confidence: 99%

A Colloidal Self-Organization of Impurities in a Liquid by Density Fluctuations

Shimkevich¹

2018

Chaos Theory

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The two-parametric functional for weakly interacting fluctuations of liquid density and composition is studied within the theory based on Landau potential for these fluctuations in the kind of ensemble of phonons and compound clusters. Using the standard diagram technique, the task for weak-interacting phonons and clusters is reduced to solving the equations of proper-energetic functions of quasi-particle interaction by Neumann iterations of Feynman diagrams in "bootstrapping" of Fourier images (propagators) for correlation of the composition of liquid and its topological structure. It is shown that composition fluctuations as clusters are induced by phonons when impurity atoms being initially outside the dense part of liquid (introduction solution) become inherent constituents of the dense part (addition solution). By renormalizing parameters of the model, we have transformed weakly interacting fluctuations to free "dressed" phonons and clusters whose autocorrelation functions are characterized by various behaviors in small and large scales in comparison with the atomic spacing. In the first case, density fluctuations of liquid do not feel impurities. In the intermediate scale, the liquid matrix is inhomogeneous in the form of colloids, which is not observed at the large scales. Dynamics of such liquid is characterized by diffusion modes of solvent and oscillations of impurities.

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Topological structure of density fluctuations in condensed matter

Cited by 8 publications

References 8 publications

Eutectic Na–Tl and Pb–Mg alloys as liquid-metal coolants for fast nuclear reactors

Eutectic Na–Tl and Pb–Mg alloys as liquid-metal coolants for fast nuclear reactors

On Clustering Impurities by Liquid Density Fluctuations

A Colloidal Self-Organization of Impurities in a Liquid by Density Fluctuations

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