scholarly journals Simulation of Sowing Precision in Laboratory Conditions

2021 ◽  
Vol 11 (14) ◽  
pp. 6264
Author(s):  
Dan Cujbescu ◽  
Iuliana Găgeanu ◽  
Cătălin Persu ◽  
Mihai Matache ◽  
Valentin Vlăduț ◽  
...  
Keyword(s):  
Meteorological Factors ◽  
Operating Conditions ◽  
Real Field ◽  
Labor Costs ◽  
Laboratory Conditions ◽  
Stationary Conditions ◽  
Agricultural Producer ◽  
Seedbed Preparation ◽  
Production Losses

In agrotechnical practice, it was found that between qualitative indices, which express the sowing precision achieved by precision planters determined in the laboratory, and those determined under operating conditions, that there are certain differences, which are sometimes quite significant. The decrease in the value of the quality indices was manifested by the increase of the number of mistakes, either of the number of double planting holes (with at least two seeds), or of the number of missing planting holes. Both cases are unfavorable for the agricultural producer, generating production losses. This paper discusses the influence of the degree of soil grinding on sowing precision in operating conditions, by determining the spectrum of the vibrations induced in the mechanical structure of row units of a precision planter in contact with the soil of three different plots for three working speeds: 4, 6, and 8 km·h−1. Later, the vibrations were simulated under laboratory conditions, on the stand, by means of rubber hemispheres (with diameters between 30 and 100 mm, corresponding to soil fractions resulting from the determination of the degree of soil grinding) mounted on rubber bands, which actuated the seed meters, for testing under an accelerated regime, outside of the optimal agricultural periods (out of season: beginning mid-May until the end of March), in order to obtain the accuracy of the precision planters. It was found that the sowing precision determined in stationary conditions on the stand, and on a plot with an appropriate degree of seedbed preparation, decreased between 2.92% (at 4 km·h−1) and 6.67% (at 8 km·h−1). The main objective of the tests was to reduce labor costs, which was necessary for the staff involved for determining the qualitative indices of work in real field operating conditions, eliminating fuel consumption, while reducing the duration of testing dependent on meteorological factors (season, temperatures, and precipitation, etc.).

scholarly journals PROCESS MODELING OF THE FIRST MECHANICAL CROP TENDING OF CULTIVATED CROP IN LABORATORY CONDITIONS

2020 ◽  
pp. 6-13
Author(s):  
Е. S. Zykin ◽  
◽  
V. I. Kurdyumov ◽  
Keyword(s):  
Statistical Treatment ◽  
Empirical Support ◽  
Optimization Criterion ◽  
Operating Conditions ◽  
Cultivated Plants ◽  
Laboratory Conditions ◽  
Flat Disk ◽  
Speed Change ◽  
Geometrical Dimensions

Conducted analysis of calculation methods of estimated figures of facilities for crop tending of cultivated crop according to hilled technology showed that in the theories of determination of geometrical dimensions and shapes of working parts surfaces of inter-row cultivator now some points are left, which are not solved . Besides, obtained data from studies of many scientists can be applied to new working tool with flat discs for inter-row cultivator. Consequently, additional theoretical and empirical support of optimal constructive-operating conditions of above mentioned working tools of inter-row cultivator is demanded. For mechanized crop tending of cultivated crop according to hilled technology we offered working tool of inter-row cultivator with flat disc, set for native or foreign inter- row cultivator. Offered working tool of cultivator will allow to clip off pest in seed inter rows of cultivated plants, and also dust not cut pests on the flanks of ridges and between culms of cultivated crop on upper base of soil rigs . In the article process of formation of secondary soil rigs by working tools with flat discs during modeling the first mechanized crop tending of cultivated crops in laboratory conditions is observed. Considering agrotechnical requirements and physical mechanical properties of soil, reference profile of soil rigs is accepted, forming during mechanized crop tending, which conditionally can accept as ideal, and an original optimization criterion . After practical realization of research in soil box and statistical treatment of obtained data fit equations were got, in which independent factors of process took the form of natural and coded levels. It was found out that speed change of cultivator moving within 1,2...2,4 m/s, angled к of flat disk approach angle from 5º to 20º, increases the range of soil throwing away and width of soil dust on the flanks and upper base of the first soil rigs (kсэ → max). At the angle of  attack of flat discs within 25º...30º and cultivator conveying speed from1,2 m/s to 1,6 m/s there is growth of width of dusted layers hпр, an coefficient kсэ is maximum (kсэ = 0,98 with diameter of flat discs 0,3 m).

Simulation and Contrast Analysis of tem Images of Cracks

1990 ◽  
Vol 48 (1) ◽  
pp. 578-579
Author(s):  
D. Goyal ◽  
A. H. King
Keyword(s):  
Displacement Vector ◽  
Crack Tip ◽  
Perfect Crystal ◽  
Operating Conditions ◽  
Displacement Fields ◽  
Fringe Contrast ◽  
Orthogonal Geometry ◽  
Moire Fringe ◽  
Moiré Fringe

TEM images of cracks have been found to give rise to a moiré fringe type of contrast. It is apparent that the moire fringe contrast is observed because of the presence of a fault in a perfect crystal, and is characteristic of the fault geometry and the diffracting conditions in the TEM. Various studies have reported that the moire fringe contrast observed due to the presence of a crack in an otherwise perfect crystal is distinctive of the mode of crack. This paper describes a technique to study the geometry and mode of the cracks by comparing the images they produce in the TEM because of the effect that their displacement fields have on the diffraction of electrons by the crystal (containing a crack) with the corresponding theoretical images. In order to formulate a means of matching experimental images with theoretical ones, displacement fields of dislocations present (if any) in the vicinity of the crack are not considered, only the effect of the displacement field of the crack is considered.The theoretical images are obtained using a computer program based on the two beam approximation of the dynamical theory of diffraction contrast for an imperfect crystal. The procedures for the determination of the various parameters involved in these computations have been well documented. There are three basic modes of crack. Preliminary studies were carried out considering the simplest form of crack geometries, i. e., mode I, II, III and the mixed modes, with orthogonal crack geometries. It was found that the contrast obtained from each mode is very distinct. The effect of variation of operating conditions such as diffracting vector (), the deviation parameter (ω), the electron beam direction () and the displacement vector were studied. It has been found that any small change in the above parameters can result in a drastic change in the contrast. The most important parameter for the matching of the theoretical and the experimental images was found to be the determination of the geometry of the crack under consideration. In order to be able to simulate the crack image shown in Figure 1, the crack geometry was modified from a orthogonal geometry to one with a crack tip inclined to the original crack front. The variation in the crack tip direction resulted in the variation of the displacement vector also. Figure 1 is a cross-sectional micrograph of a silicon wafer with a chromium film on top, showing a crack in the silicon.

Determination of cores electrification during the flow in the modified Wurster apparatus

2016 ◽  
Vol 1 (20) ◽  
pp. 5-15
Author(s):  
Wojciech Ludwig ◽  
Tadeusz Mączka
Keyword(s):  
Measurement System ◽  
Charge Accumulation ◽  
Laboratory Conditions ◽  
Pharmaceutical Materials

The purpose of this paper was presentation of the value of cores electrification during their flow in the modified Wurster apparatus, applied for dry encapsulation of pharmaceutical materials. Previous works of the authors dealt with vulnerability of the particles of different diameter, produced by SYNTAPHARM (Cellets 1000, 700 and 100) on electrification in laboratory conditions. The presented work gives the results of examination on particles electrification in real conditions of their stable circulation in a column. The measurement system, that was applied, allowed determination of electrification potential and electrification current. Those quantities, which are the measures of charge accumulation on cores were determined for several particles (Cellets 1000, 700 and 500) with the different humidity, for different mass of the bed and spouting gas velocities.

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