The Experts below are selected from a list of 113625 Experts worldwide ranked by ideXlab platform

Ioannis Chatzis - One of the best experts on this subject based on the ideXlab platform.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    Abstract This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure—a lower dimensional representation of the pore Space akin to the Topological “deformation retract”. The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of λ-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure-a lower dimensional representation of the pore Space akin to the Topological "deformation retract". The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of lambda-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area. Copyright 2000 Academic Press.

Z Liang - One of the best experts on this subject based on the ideXlab platform.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    Abstract This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure—a lower dimensional representation of the pore Space akin to the Topological “deformation retract”. The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of λ-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure-a lower dimensional representation of the pore Space akin to the Topological "deformation retract". The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of lambda-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area. Copyright 2000 Academic Press.

Marios A Ioannidis - One of the best experts on this subject based on the ideXlab platform.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    Abstract This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure—a lower dimensional representation of the pore Space akin to the Topological “deformation retract”. The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of λ-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area.

  • geometric and Topological analysis of three dimensional porous media pore Space partitioning based on morphological skeletonization
    Journal of Colloid and Interface Science, 2000
    Co-Authors: Z Liang, Marios A Ioannidis, Ioannis Chatzis
    Abstract:

    This article presents a versatile, rigorous, and efficient methodology for extracting various geometric and Topological parameters of 3D discrete porous media. The new approach takes advantage of the morphological skeleton of the pore structure-a lower dimensional representation of the pore Space akin to the Topological "deformation retract". The skeleton is derived by a fully parallel thinning algorithm that fulfils two essential requirements: it generates a medial axis and preserves the connectivity of the pore Space. Topological analysis is accomplished by classifying all skeleton points as node or link (branch) points according to the concept of lambda-adjacency in 3D discrete Space. In this manner, node coordination number and link length distributions are directly obtained from the skeleton. Pore necks (throats) are identified through a search for minima in the hydraulic radius of individual pore Space channels outlined by skeleton links. In addition to the determination of the size distribution of the constrictions (pore necks) that control nonwetting phase invasion, improved estimates of the distributions of effective hydraulic and electric conductivity of individual pore Space channels are obtained. Furthermore, erection of planes at the location of pore necks results in partitioning of the pore Space into its constituent pores. This enables the characterization of the pore Space in terms of a pore volume distribution. The new methodology is illustrated by application to a regular cubic pore network and irregularly shaped 2D and 3D pore networks generated by stochastic simulation. In the latter case, important new results are obtained concerning the sensitivity of geometric and Topological properties of the microstructure to the parameters of stochastic simulation, namely, the porosity and correlation function. It is found that model porous media reconstructed from the same porosity and correlation function can exhibit marked differences in geometry and connectivity, which correlate with differences in specific surface area. Copyright 2000 Academic Press.

G E Volovik - One of the best experts on this subject based on the ideXlab platform.

  • momentum Space Topological invariants for the 4d relativistic vacua with mass gap
    Nuclear Physics, 2012
    Co-Authors: M A Zubkov, G E Volovik
    Abstract:

    Topological invariants for the 4D gapped system are discussed with application to the quantum vacua of relativistic quantum fields. Expression ˜ N3 for the 4D systems with mass gap defined in [13] is considered. It is demonstrated that ˜ N3 remains the Topological invariant when the interacting theory in deep ultraviolet is effectively massless. We also consider the 5D systems and demonstrate how 4D invariants emerge as a result of the dimensional reduction. In particular, the new 4D invariant ˜ N5 is suggested. The index theorem is proved that defines the number of massless fermions nF in the intermediate vacuum, which exists at the transition line between the massive vacua with different values of ˜

Volovik G. E. - One of the best experts on this subject based on the ideXlab platform.

  • Elasticity tetrads, mixed axial-gravitational anomalies, and 3+1d quantum Hall effect
    'American Physical Society (APS)', 2019
    Co-Authors: Nissinen J., Volovik G. E.
    Abstract:

    For two-dimensional Topological insulators, the integer and intrinsic (without external magnetic field) quantum Hall effect is described by the gauge anomalous (2+1)-dimensional [2+1d] Chern-Simons (CS) response for the background gauge potential of the electromagnetic U(1) field. The Hall conductance is given by the quantized prefactor of the CS term, which is a momentum-Space Topological invariant. Here, we show that three-dimensional crystalline Topological insulators with no other symmetries are described by a Topological (3+1)-dimensional [3+1d] mixed CS term. In addition to the electromagnetic U(1) gauge field, this term contains elasticity tetrad fields $E^{\ a}_{\mu}({\bf r},t) = \partial_{\mu}X^a(\mathbf{r},t)$ which are gradients of crystalline U(1) phase fields $X^a(\mathbf{r},t)$ and describe the deformations of the crystal. For a crystal in three spatial dimensions $a=1,2,3$ and the mixed axial-gravitational response contains three parameters protected by crystalline symmetries: the weak momentum-Space Topological invariants. The response of the Hall conductance to the deformations of the crystal is quantized in terms of these invariants. In the presence of dislocations, the anomalous 3+1d CS term describes the Callan-Harvey anomaly inflow mechanism. The response can be extended to all odd spatial dimensions. The elasticity tetrads, being the gradients of the lattice U(1) fields, have canonical dimension of inverse length. Similarly, if such tetrad fields enter general relativity, the metric becomes dimensionful, but the physical parameters, such as Newton's constant, the cosmological constant, and masses of particles, become dimensionless.Comment: 9 pages, 1 figure. Published versio

  • Elasticity tetrads, mixed axial-gravitational anomalies, and (3+1)-d quantum Hall effect
    'American Physical Society (APS)', 2019
    Co-Authors: Nissinen J., Volovik G. E.
    Abstract:

    | openaire: EC/H2020/694248/EU//TOPVACFor two-dimensional Topological insulators, the integer and intrinsic (without external magnetic field) quantum Hall effect is described by the gauge anomalous (2+1)-dimensional [(2+1)-d] Chern-Simons (CS) response for the background gauge potential of the electromagnetic U(1) field. The Hall conductance is given by the quantized prefactor of the CS term, which is a momentum-Space Topological invariant. Here, we show that three-dimensional crystalline Topological insulators with no other symmetries are described by a Topological (3+1)-dimensional [(3+1)-d] mixed CS term. In addition to the electromagnetic U(1) gauge field, this term contains elasticity tetrad fields E-mu(a) (r, t) = partial derivative X-mu(a) (r, t) which are gradients of crystalline U(1) phase fields X-a (r, t) and describe the deformations of the crystal. For a crystal in three spatial dimensions a = 1, 2, 3 and the mixed axial-gravitational response contains three parameters protected by crystalline symmetries: the weak momentum-Space Topological invariants. The response of the Hall conductance to the deformations of the crystal is quantized in terms of these invariants. In the presence of dislocations, the anomalous (3+1)-d CS term describes the Callan-Harvey anomaly inflow mechanism. The response can be extended to all odd spatial dimensions. The elasticity tetrads, being the gradients of the lattice U(1) fields, have canonical dimension of inverse length. Similarly, if such tetrad fields enter general relativity, the metric becomes dimensionful, but the physical parameters, such as Newton's constant, the cosmological constant, and masses of particles, become dimensionless.Peer reviewe