abstract:        The purpose of this work is to review methods applied in measurements of physical proprieties of granulated agricultural materials from the perspective of attempting to establish uniform measuring standards. Analysis of the present situation showed a lack of accepted and generally recognized standards of measurement of the physico-mechanical proprieties of seeds in Poland at this time. In some cases there exist industry standards, which allow for standardized measurements of certain physical proprieties relevant to the given technological process. The quantities, in these cases, are usually defined in conventional units, which do not allow their use in general physics theories.
       There are two, often not overlapping, paths of testing. The first one proposes to test individual seeds. The majority of current measurements conducted in these types of studies stem from those used in testing constructional materials. Whereas in case of classic strength there exists a fully cohesive and unambiguous terminology, the tests of biological material are somewhat chaotic. The terminology used is often inadequate in describing the proprieties. The studies conducted showed, that the ASAE standard, applied in defining Young's modulus, does not fulfill the requirements regarding accuracy and repeatability of the obtained results. The conducted analysis permitted to affirm, that this is due to the incorrect use of the laws of continuous medium mechanics in describing the behavior of seeds under stress. For that reason, the authors proposed new methods for defining the elasticity and hardness of individual seeds. These methods took into account the seeds’ specific material properties (especially their typically rheological character).
       Calculations were also done to see if any connections exist between a seed's elasticity coefficient and its hardness. The artificial neuronal nets were used for that. It turned out, that in order to increase the accuracy of the prognosis, it is necessary to divide the seeds into groups, based on their water content of and theoretical density.
       The second, dynamically growing, path is made up of tests carried out on seeds deposited in one place, for example stored in silos. The variety of methods used here often led to miscommunication between the representatives of the different testing centers. The same term may have two completely different meanings. The same holds true for the process of developing the profiles of materials. The work goes on simultaneously in many different directions, depending on the interests of the individual groups. The authors analyzed the existing situation and forecasted the directions in which the standardization of methods of characterizing granulated materials may progress in the individual groups of use.
       Among the methods of measurement used to verify the constitutional models of the material, the method of triaxial compression will remain the main point of reference. This method is in reality not truly "triaxial", but there are no other effective and more exact testing methods of this sort on hand today. Every new method is verified by comparing its results with these of the traditional method.
       In designing silos, construction engineering will continue to follow the direct cutting method, well known in this field as the Jenike's method. The priority of this method was explicitly stated in Eurocode 1 - the European design standard. It is recommended as the method of choice for determining the strength of stored materials. The authors' tests have shown that the method, as far Eurocode 1 specified uses are concerned, is suitable for use with grain cereals and other materials of biological origin. However, in the case of moist material, the path of the cut needs to be extended.
       Another promising area of measurement method development is the in-line control. This field is still in its initial stage, but considering the benefits arising from controlling the process, that are cutting the costs and stabilizing product quality, one can expect fast headway. Many different transducer types are in use, and new ones are being developed. The main challenges at hand are: the lowering of transducer costs, increasing its reliability, developing data processing programs for use in changing transducer signals into information useful in controlling the process.

original in: Polish