Conductivity Of Two-phase Materials Research Articles

Evaluation of microstructure and conductivity of two-phase materials by the scanning spreading resistance microscopy (the case of shungite)

The determination of the content of the conducting phase and the assessment of conductivity by microscopic images are interesting for rapid and non-destructive analysis of the electrophysical properties of two-phase (conductor/dielectric) samples during the atomic force microscopy. In this paper we summarized results of the analysis of the conductivity maps of the shungite surface by the method of discretization by applying a square grid with subsequent binary digital processing. Microstructure and conductivity were evaluated by measuring the average length of continuous conductive circuits isolated on the grid. A model was considered that established a unique correspondence (up to normalizing coefficients) between the length of the conductive circuits on the conductivity maps and the integral conductivity of the sample as a whole. An analytical equation was obtained that described such dependence with an accuracy of units of percent. We proposed a method for measuring the integral conductivity of a shungite samples based on an analysis of its binary conductivity map obtained by spreading resistance microscopy. This method can be used to determine the conductivity by surface conductivity mapping for shungite-like two-phase conductor/dielectric systems, and in general, for any two-phase substances where the phases differ in AFM-determined properties.

Development of Analytical Model to Estimate the Effective Thermal Conductivity of Two-Phase Materials with Nano Particles

In this item, the geometry reliant on confrontation model is used to approximation the real thermal conductivity (ETC) of the two-phase resources with nanoparticles founded on the unit cell method.

Estimation of Effective Thermal Conductivity of Two-Phase Materials with Nano Particles and Development of Analytical Model

In this item, the geometry reliant on confrontation model is used to approximation the real thermal conductivity (ETC) of the two-phase resources within an oparticles founded on the unit cell method. The equations are resulting depends on isotherm method for two dimensional spatially episodic average. The models are used to forecast the effective thermal conductivity of two-phase supplies with nano subdivisions. Geometry of the intermediate is cautious as a matrix of poignant and non touching in line tetragonal. The actual thermal conductivity of two-phase substantial with nano sub division is found and associated with many conformist models. Comparison of prophesied values of the untried results is also completed.

Geometrical comparison study based on numerical modeling to estimate the effective thermal conductivity of two-phase material with natural convection effect

Geometrical comparison study based on numerical modeling to estimate the effective thermal conductivity of two-phase material with natural convection effect

Evaluation of Effective Thermal Conductivity for Mineral Cast Structural Materials Using Steady-State and Transient Methods

Abstract Thermal conductivity is a thermophysical property that represents the rate at which heat energy can be transported through the material. For any alternate material chosen for machine tool structures, the study of its thermal characteristics is imminent. Thermal conductivity is one major characteristic to be analysed. Mineral cast structures made of epoxy-granite are found to exhibit good mechanical properties, such as high stiffness and damping ratio. The material also has lesser weight, compared to conventional materials used for machine tool structures. Hence, these materials are emerging as an alternate to conventional cast iron machine tool structures. This study attempts to determine the effective thermal conductivity of epoxy granite material using steady-state and transient plane source (TPS) methods. The results obtained using the experimental methods are compared with geometrical models and the suitability of the methods is evaluated. It is observed that both methods are suitable for measuring effective thermal conductivity of two-phase materials. Compared to TPS method, the steady-state method is a slow and material-consuming technique but provides more accurate results. The effective thermal conductivity of the developed material is compared with some commercial polymer composites and observed that the developed material has greater thermal conductivity.

Influence of contact resistance and natural convection effects on non-dimensional effective thermal conductivity estimation of two-phase materials

In this article, the development of geometry dependent resistance model by considering contact resistance and natural convection effects are used to estimate the effective thermal conductivity of two-phase materials based on the unit cell approach. The algebraic equations have been derived based on isotherm approach for 2-D and 3-D spatially periodic medium. Comparison study has been made between developed models and experimental data. The result agrees well with experimental values.

Estimation of Effective Thermal Conductivity of Two-Phase Materials by Considering the Knudsen Effect: An Analytical Approach

In this article, the analytic model has been developed to estimate the effective thermal conductivity (ETC) of two-phase materials based on the unit cell approach by considering the concentration, conductivity ratio, contact resistance, and Knudsen effect. The derivations of algebraic equations for standard geometry, such as hexagon and octagon cylinder models are developed based on parallel isotherm approach. The developed analytic model has been used to predict the thermal conductivity of various two-phase materials (conductivity ratio, α = 3.11-310.86 and concentration, ν = 0.05 and 0.74). The present models are validated using the standard models and compared with the experimental data. Further the comparison is made between the present models and existing models. The results are in good agreement.

Comparison of geometry dependent resistance models with conventional models for estimation of effective thermal conductivity of two-phase materials

The geometry dependent resistance models are used to estimate the effective thermal conductivity of two-phase materials based on the unit cell approach. The algebraic equations are derived based on isotherm approach for various geometries. The effective thermal conductivity of the above models are found and compared with experimental data with a minimum and maximum deviation of ±3.976 and ±19.55%, respectively. The present models are good agreement with experimental results.

Cellular effective medium approximation for the conductivity of two-phase materials

Cellular effective medium approximation for the conductivity of two-phase materials

Cellular effective medium approximation for the conductivity of two-phase materials

To derive the conductivity of inhomogeneous two-phase materials, an effective medium approximation is developed in terms of two types of cells formed around the inhomogeneity. Their sizes and numbers vary with the concentration of inhomogeneity. This method provides a general form including other well known approximations as special cases.