Analysis of Volume Distribution and Evaluation of the Spraying Spectrum in Terms of Spraying Quality

Assessment of the quality of the operation of agricultural nozzles on the basis of transverse volume distribution and spatial methods of analysis for stream spraying spectra is insufficient, and positive result do not guarantee that the intended and effective spraying effects are obtained. Tests were carried out to assess the quality of nozzles on the basis of transverse volume distribution analysis, microstructure characteristics, and detailed analysis of places where an unexpected change in the nature of the transverse volume distribution (increase in volume) was noted. The subjects of the study were RS11003 flat fan nozzles and a measuring stand equipped with a grooved table, which was used to carry out tests. During the tests, the unit flow rate from the nozzles, the transverse volume distribution of liquids from individual table grooves, and the corresponding CV distribution coefficients of variation were recorded. Detailed tests were carried out for the selected nozzle, consisting of spot measurement of droplet characteristics in individual liquid stream bands. The widths of these bands were constant and equal to the width of the measuring table groove. Measurements were made using analyzer 2D-Laser Doppler Anemometry/Phase Doppler Anemometry (2D-LDA/PDA) from Dantec Dynamics. The analysis of the results obtained from the grooved table and the droplet characteristics in individual stream bands showed clear and unexpected changes in the nature of the transverse volume distribution for all tested nozzles. These changes, consisting of a local increases in droplet diameters (with a reduced number of occurrences), can cause a significant reduction in the quality and effectiveness of spraying, despite the positive fulfillment of generalized normative criteria for their assessment.

Foliations by minimal surfaces and contact structures on certain closed3-manifolds

Let(M,g)be a closed, connected, orientedC∞Riemannian 3-manifold with tangentially oriented flowF. Suppose thatFadmits a basic transverse volume formμand mean curvature one-formκwhich is horizontally closed. Let{X,Y}be any pair of basic vector fields, soμ(X,Y)=1. Suppose further that the globally defined vector𝒱[X,Y]tangent to the flow satisfies[Z.𝒱[X,Y]]=fZ𝒱[X,Y]for any basic vector fieldZand for some functionfZdepending onZ. Then,𝒱[X,Y]is either always zero andH, the distribution orthogonal to the flow inT(M), is integrable with minimal leaves, or𝒱[X,Y]never vanishes andHis a contact structure. If additionally,Mhas a finite-fundamental group, then𝒱[X,Y]never vanishes onM, by the above together with a theorem of Sullivan (1979). In this caseHis always a contact structure. We conclude with some simple examples.