arXiv subjects

Enis Tuncer

Publications and source records attributed to Enis Tuncer.

23 records · Page 2Linked to original sources

arXiv2004

Extracting spectral density function of a binary composite without a-priori assumption

The spectral representation separates the contributions of geometrical arrangement (topology) and intrinsic constituent properties in a composite. The aim of paper is to present a numerical algorithm based on the Monte Carlo integration and contrainted-least-squares methods to resolve the spectral density function for a given system. The numerical method is verified by comparing the results with those of Maxwell-Garnett effective permittivity expression. Later, it is applied to a well-studied rock-and-brine system to instruct its utility. The presented method yields significant microstructural information in improving our understanding how microstructure influences the macroscopic behaviour of composites without any intricate mathematics.

cond-mat.other↗

arXiv2002

How round is round? On accuracy in complex dielectric permittivity calculations: A finite-size scaling approach

Accuracy in complex dielectric permittivity calculations in binary dielectric mixtures in two-dimensions are reported by taking into account the shape of the inclusion phase. The dielectric permittivity of the mixtures were calculated using the finite element, and the permittivities were estimated by two different procedures. The results were compared with those of analytical models based on mean field approximation and regular arrangement of disks. We have approached the problem emphasizing the finite-size behavior in which regular polygons with $n$ sides were assumed to mimic the disk inclusion phase. It was found that at low concentrations, $< 30 %$, considering an decagon ($n=10$) cause an error of $<0.1 %$ in the effective medium quantities compared with the results obtained using the analytical models.

cond-mat.mtrl-sci↗

arXiv2002

Dielectric properties of a two dimensional binary sytem with ellipse inclusions

A two-dimensional binary composite system composed of ellipse inclusions and a host medium is considered. Dielectric permittivity of the system is calculated as a function of orientation angle, the volume fraction of the inclusions and their excentricity using the finite element method. It was observed that both the orientation of the inclusions in the field and their excentricity have significant effects on the dielectric permittivity.

cond-mat.mtrl-sci↗

arXiv2002

On complex permittivity of dilute random binary dielectric mixtures in two-dimensions

Influence of number of particles considered in numerical simulations on complex dielectric permittivity of binary dilute dielectric mixtures in two-dimensions are reported. In the simulations, dodecagons (polygons with 12-sides) were used to mimic disk-shaped inclusions. Using such an approach we were able to consider $16^2$ particles in a unit-square. The effective dielectric permittivity of the mixtures were calculated using the finite element at two different frequecies which were much higher and lower than the characteristic relaxation rate of the Maxwell-Wagner-Sillars polarization. The results were compared to an analytical solution. It was found that the permittivity values at low frequencies were inside Wiener bounds however they violated the Hashin-Shtrikman bounds.

cond-mat.mtrl-sci↗

arXiv2001

Dielectric mixtures -- electrical properties and modeling

In this paper, a review on dielectric mixtures and the importance of the numerical simulations of dielectric mixtures are presented. It stresses on the interfacial polarization observed in mixtures. It is shown that this polarization can yield different dielectric responses depending on the properties of the constituents and their concentrations. Open question on the subject are also introduced.

cond-mat.mtrl-sci↗