Technikatörténeti szemle 10. (1978)

A MÉRÉS ÉS A MÉRTÉKEK AZ EMBER MŰVELŐDÉSÉBEN című konferencián Budapesten, 1976. április 27–30-án elhangzott előadások II. - Tálos Gy.: A reológiai mérési módszerek fejlődésének története Newtontól napjainkig

in the rubber industry; the qualification of latexes according to their flow properties and the qualification of the end products according to their high elastic properties, in the textile industry; the control of the processes during the production and the processing of the fibres, in the food and cosmetic industry practically all the products can be qualified with rheometry in connection with the points of view of both their enjoyment and stability for conservation, for constructing of roads; the rheological characterization of asphalts and bitumens, and from the circle of the special technological and scientific claims the followings can be emphasized: the rheological methods and the rheometry in connection with the lubrication, which—today—has a role in the space research too, in the colloid chemistry; e.g. the importance of rheology of certain surface phenomena or the adhesive rheology in connection with gluing, in the biophysics; e.g. relations between the rheological parameters and certain pathological conditions of some biological systems or rheological modelling of some biophysical processes, in the geophysics; the deformations of the earth's crust; crust's movings on the litosphere, the flow of the litosphere or e.g. amongst the surface phenomena; the flow of glaciers. Nowadays the science of rheology and rheometry has been divided into lot of branches. There is no ,.general rheologist", everybody can devote his life to a narrow field and the result reached by him—compared to other sciences—seems very modest. That is why so few devote their lives to it however, the claim to it—e.g. according to a concrete survey in the U.S.A.—would be greater. But—if somebody has acquired the basic mathematical knowledge—this science gives much pleasures and surprises for him. At the same time, people, who deal with rheometry today and in addition who dares to solve special flow problems and to construct new instruments, must be— among others—physicist, colloid chemist, mechanical engineer and optician too. I.e. now, the terms of the rheological parameters claim not only mechanical, but statistical, thermodinamical and colloid chemical structural approach too. So, the phenomenological macrorheological and the microrheological treatment are separated. In spite of this, their relation cann't to be separated, because macroscopic deformations are measured with proper instruments, but for the knowledge of the processes taking place in the instruments; one has to know the micro- and the colloidstructures of the materials in connection with the appropriate terms of rheometry. According to a different point of view; there are laboratory and industrial rheometries. Difficulties of the latter are that sometimes excessively complex systems have to be examined by simple methods, so it is no wonder, that many times their results cann't be expressed explicitely with the parameters of rheological state. As I cann't deal with all the history of this science in the scope of such a short lecture, I'll draw up shortly the development of such terms and instruments of rheometry, which—in the industrial and laboratory practice—are of decisive majority