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Technological processing of loose materials of biological origin involves
their contact with the working parts of the equipment. This causes damage at
both micro- and macrolevels. A method for identifying the level of damage to
biological origin has been proposed. The developed algorithm for metrological
identification includes the following stages: preparation of the samples; static /
dynamic loading of samples; tomography of objects (Zeiss Xradia 510
tomograph); analysis and identification of damage parameters (Monte Carlo
static processing method). Due to the preliminary calibration of materials of
biological origin on laboratory sieves of the sifter, they were weighed and dried,
we obtained samples with identical parameters [1]: thickness, width, length,
density, moisture content. The second stage is an external simulation load of the
selected samples, which was performed by: Zwick/Roell 2.5 universal test bench
(static nature of the load), developed impact test bench (dynamic nature of the
load) [2]. During this process, the position of the samples was changed:
horizontal or vertical. The obtained critical loads (complete destruction of the
samples) were differentiated into three levels: 30%, 60%, and 90% of the critical
load. This allowed for the preparation of samples with varying magnitudes and
directions of external load. The next stage involved tomography of the damaged
samples, which was carried out using the Zeiss Xradia 510 Versa 3D tomograph
at LUT. Parameters of tomograph: 4X lens; maximum 3D FOV (WFM) –
6(10) mm; voxel size – 0,7÷3 μm; average tomography time is 3.4 hours. Results
of the tomography: a series of 2D images (10 horizontal and 10 vertical cross-
sections of the BO); 3D images. The difficulty is in analyzing 3D images and
determining of damage parameters. For analyses of 20 pieces (2D images) for
one BO we proposed the Monte Carlo statistical testing method with the
following algorithm data processing [3]: applied a grid on the tomographic
image of the BO (we used 3400 points per 1 image), checked if the points of this
grid hit the cracks (ξi ), error analysis, analysis of the BO damage level. In theresulting equation for identifying the micro-damage coefficient we have
3 options: first, when a point getting into a crack we got random variable equals
0, second, a point getting into a boundary – got random variable equals 0.5, and
getting a point into a solid equals 1. The verification of this metrological
identification was conducted on loose materials – specifically, corn seeds.
A dependency of the microdamage coefficient on the parameters of the external
load was established. The adequacy of this method was verified using sample
microscopy, with data discrepancies not exceeding 3.6%. The developed method
allows to perform metrological measurements of the damage levels of loose
material particles of biological origin, which determines their quality, period of
storage and reproductive properties [4].
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