До питання визначення електропровідності натуральної шкіри

Abstract

Питання про характер впливу вологи, що міститься в натуральній шкірі, на її електричні властивості (електропровідність, діелектричну проникність, діелектричні втрати) мало досліджені теоретично. Водночас бажано визначити наближені й зручні методи теоретичного оцінювання електричних характеристик. Оскільки колоїдні капілярно-пористі тіла мають складну структуру, що змінюється під час зволоження (унаслідок набрякання), запропонований метод заслуговує на увагу.

The questions arising in practice and concerning the nature of the influence of moisture contained in natural leather on its electrical properties (electrical resistivity, dielectric constant, dielectric losses) are poorly studied theoretically. At the same time, approximate, but rather simple and convenient methods of theoretical evaluation of electrical characteristics are very desirable. In this paper, the authors propose the method for calculating electrical resistance of capillary porous bodies on the basis of a capillary model, according to which real bodies are represented as a "bundle of capillaries" of different radii from one surface to the other. Taking into account the fact that colloidal capillary-porous bodies have a complex structure changing in the process of hydration (due to swelling), the proposed method deserves attention. We calculated electrical resistance for hard leather samples. Analy tical form of the differential function of pores distribution along the radii for these samples was determined earlier. Impregnation of skin with water leads to the appearance of a finite resistance of the sample, which sharply decreases, due to the formation of conductive water bridges between electrodes, which are completely filled with water pores. The curves of the standard dependences of the "effective" conductivity on the moisture content can be useful for practical assessments of conductivity and resistances of moistened skin samples, in particular for the preliminary calibration of electric moisture meters. The combination of scales along the abscissa axis is a significant drawback of the proposed method for calculating electrical resistivity of damp skin. However, taking into account that colloidal capillary-porous bodies have a complex structure that changes during the process of its moistening (due to swelling), the proposed method deserves attention. It is essential that the shape of the curves for resistance, as well as for conductivity, depends on the method of changing resistance.