Analytical Determination of the Bending Stiffness of a Five-Layer Corrugated Cardboard with Imperfections

Bending stiffness (BS) is one of the two most important mechanical parameters of corrugated board. The second is edge crush resistance (ECT). Both are used in many analytical formulas to assess the load capacity of corrugated cardboard packaging. Therefore, the correct determination of bending stiffness is crucial in the design of corrugated board structures. This paper focuses on the analytical determination of BS based on the known parameters of the constituent papers and the geometry of the corrugated layers. The work analyzes in detail the dependence of the bending stiffness of an asymmetric, five-layer corrugated cardboard on the sample arrangement. A specimen bent so that the layers on the lower wave side are compressed has approximately 10% higher stiffness value. This is due to imperfections, which are particularly important in the case of compression of very thin liners. The study showed that imperfection at the level of a few microns causes noticeable drops in bending stiffness. The method has also been validated by means of experimental data from the literature and simple numerical finite element model (FEM). The obtained compliance of the computational model with the experimental model is very satisfactory. The work also included a critical discussion of the already published data and observations of other scientists in the field.

The Effects of Formulation on Imidacloprid Dissipation in Grapes and Vine Leaves and on Required Pre-Harvest Intervals under Lebanese Climatic Conditions

In this study, imidacloprid, a systemic insecticide, currently having a specified European Commission MRL value for vine leaves (2 mg kg−1), was applied on a Lebanese vineyard under different commercial formulations: as a soluble liquid (SL) and water dispersible granules (WDG). In Lebanon, many commercial formulations of imidacloprid are subject to the same critical good agricultural practice (cGAP). It was, therefore, important to verify the variability in dissipation patterns according to matrix nature and formulation type. Random samplings of grapes and vine leaves were performed starting at 2 days until 18 days after treatment. Residue extractions were performed according to the QuEChERS method and the analytical determination using liquid chromatography coupled to tandem mass spectrometry (LC-MS-MS). The SL formulation yielded significantly higher initial deposit than the WDG formulation on grapes and vine leaves. The formulation type did not significantly affect the dissipation rates; the estimated half-lives in grapes and vine leaves were 0.5 days for all imidacloprid formulations. No pre-harvest intervals were necessary on grapes. PHIs of 3.7 days for the SL formulation and 2.8 days for the WDG formulation were estimated on vine leaves. The results showed that the type of formulation and the morphological and physiological characteristics of the matrix had an effect on the initial deposits, and thus residue levels, but not on the dissipation patterns.

MATHEMATICAL MODELING OF EAR GRAIN SEPARATION PROCESS DEPENDING ON THE LENGTH OF THE AXIAL FLOW THRESHING APPARATUS

Modeling the threshing and separation process involves the application of a method of description, analysis and analytical determination of system performance: threshing apparatus - working process. The modeling of the process of separating the seeds passing through an axial flow threshing device was performed taking into account that the separation function ss(x) is given depending on the length of the threshing apparatus. Then, models were made to describe the variation of the percentage (cumulative) of separated seeds ss (x=L), corresponding to the modification of the threshing apparatus functional parameters (depending on the peripheral speed of the rotor, the flow of straw parts and the moisture of straw parts).

THEORETICAL ANALYSIS OF STRENGTH RESISTANCE TO DISPLACEMENT OF IMPROVED DIGGING WORKING BODY OF POTATOE HARVESTING COMBINE

The amount of energy required to perform technological processes in agriculture largely depends on the size of the resistance to the displacement of the working bodies of machines. The main factor of energy consumption performing the technological process of potato harvesting is the resistance to the displacement of the digestive working body. In order to reduce the resistance to displacement an improved design of the digging body is proposed. An analytical study was conducted to determine the problem of moving the working body in the soil environment. The strength of the soil resistance is determined and the regularity of the influence on its change of parameters and the shape of the blade and separation parts of the digging working body is established. Calculations are made using the Mathematica application programm. The graphic dependences and contours of the isoline of the traction flange of the working part of the working body are obtained. Analysis of the calculations allowed to set the parameters of the surface of the dashboard, which provide a minimum of traction resistance. The schedule and contours of isolines of the change of the total resistance to the displacement of the soil mass with the tubers by the separation surface of the working organ in the function of the distance between the bars and the size of their intersection are also obtained. Analysis of the dependence of soil resistance and tubers on the separation surface indicates that an increase in the size of the geometric size of the intersection of the rods leads to a significant increase in the resistance of the medium. The material presented in the article can be used for analytical determination of the resistance of the excavation working body of potato harvesting machines of arbitrary geometric shape in the soil medium with tubers.

Metacognitive processes and qualities as determinants of general management styles

The article presents theoretical and empirical materials that reveal the specifics of the main parameters of the metacognitive sphere of personality as determinants of general management styles. It is shown that one of the most constructive means of such disclosure is to identify the relationship between management styles as one of the central constructs of management psychology, on the one hand, and the main metacognitive parameters (procedural, strategic and other characteristics), on the other. The regularities of the influence of metacognitive factors on the main general management styles are established. It is shown that they are characterized by different values of the indexes of integration (coherence), differentiation (divergence) and the index of general organization of the metacognitive sphere. The provisions are formulated according to which general management styles have a structural, rather than analytical determination in relation to those metacognitive factors on the basis of which they are formed.