Dielectric Properties of Porous Media

by Gladkov, S. O.; Hull, R.; Osgood, R. M.; Parisi, J.

• ISBN13: 9783540001867
• ISBN10: 3540001867
• Format: Hardcover
• Copyright: 2003-08-01
• Publisher: Springer Verlag

Summary

This monograph systematically presents the fundamentals of theoretical and experimental research into the most important physical characteristics of porous structures. Non-standard behavior of certain physical parameters, such as the breakdown of the electric field of porous substances, is described. The method of calculation of the thermal conductivity coefficient of porous dielectrics, based on the non-equilibrium principle, is illustrated in detail. The present approach may be applied to the investigation of the properties of "disparate" substances such as cellulose matrices, composites, and fibrous structures. The book is intended for physicists, physical chemists and materials scientists at research and postgraduate and undergraduate levels. It may also be helpful for engineers and technical workers in the applied sciences.

Table of Contents

Nomenclature	XI
1 Introduction	1	(4)
2 Model of the Internal Structure of a Porous Dielectric	5	(26)
2.1 Ideal Model of a Porous Substance with Ideal Compact Packing	5	(6)
2.2 Influence of the Distribution of the Pore Volumes on the Structure Density	11	(4)
2.3 Relation Between Thermodynamic Parameters and Porosity	15	(7)
2.4 Some Data from Thermodynamics	22	(3)
2.5 Porous Media as very Viscous Liquids with Bubbles	25	(6)
3 Equilibrium Physical Parameters of Porous Dielectrics	31
3.1 The Sound Velocity in Porous Substances	31	(5)
3.2 The Heat Capacity of Dielectrics with Ideal Packing of Fibrils	36	(4)
3.3 The Transition from an Ideal Substance to a Real One	40	(1)
3.4 Temperature-Behavior Estimation of Porous Media Heat Capacity	41	(10)
3.5 Comparison with Experiment	51	(1)
3.6 Mechanical Strength of the Porous Structure: Calculation of the Break Force and Its Dependence on the Substance Density	51	(4)
3.7 Calculation of the Components of the Tension Tensor Near Macroheterogeneity	55
4 The Theory of Fast Nonstationary Phenomena in Porous Dielectrics	6l	(109)
4.1 Physical Concept of Electric and Thermal Breakdown	63	(3)
4.2 The Alternative Theory of Electric Breakdown in Porous Structures	66	(17)
4.3 The Dependence of the Breakdown Field on the Frequency of the External Oscillating Electric Field	83	(4)
4.4 Theory of Thermal Breakdown in Porous Dielectrics	87	(8)
4.5 Dependence of the Ignition Time on the Surface Temperature in Porous Dielectrics	95	(5)
4.6 The Influence of the Viscosity of the Saturating Liquid on the Electric Strength of Porous Dielectrics	100	(3)
4.7 Some Aspects of Relaxation Theory in Porous Dielectrics	103	(10)
4.8 Recommendations for Increasing the Electric and Thermal Strength of Porous Structures	113	(2)
5 On Specific Features of Thermal Conduction and Diffusion in Porous Dielectrics	115	(56)
5.1 Kubo's Formula	119	(2)
5.2 Green's Functions and Correlators	121	(2)
5.3 Calculation of the Thermal Conductivity Coefficient	123	(12)
5.4 Computer Analysis of the Formula for κ(m, &Tau)	135	(11)
5.5 Comparison with the Experimental Data	146	(2)
5.6 Diffusion Saturation of Porous Structures by Liquid (Calculation of the Diffusion Coefficient)	148	(7)
5.7 Determination of the Substance Porosity Coefficient	155	(1)
5.8 Darcy's Law (Microscopic Derivation)	156	(4)
5.9 Influence of the High-Frequency Deformation Wave on the Filtration Process	160	(4)
5.10 On the Connection of the Jou1e-Thomson Effect with Darcy's Law	164	(7)
6 Behavior of Porous Dielectrics in Acoustic and Electromagnetic Fields	171	(44)
6.1 Energy Absorption Coefficient of the External Low Frequency Electromagnetic Field of Porous Structures	174	(8)
6.2 Sound Absorption by Porous Dielectrics	182	(8)
6.3 The Fluctuation Absorption Mechanism of the Electromagnetic Field	190	(11)
6.3.1 Calculation of &alpha"(ω)	191	(5)
6.3.2 Absorption Cross-Section σ (ω)	196	(5)
6.4 Dielectric Permeability of Porous Substances	201	(6)
6.5 Explanation of the Temperature Dependence of the Loss Angel Tangent	207	(8)
7 Conclusion	215	(2)
Appendix
A Program for Heat Conductivity Coefficent κ (m, Τ) Calculation	217	(4)
B Collision Integrals and Relaxation Time Calculation	221	(16)
C Simplified Theory of Thermal Conduction in a Porous Dielectric	237	(12)
D.1 Theory of Fluctuations	249	(2)
D.2 Fluctuations of the Maui Thermodynamic Values	251	(6)
References	257