Estimating the Dynamics of A Machine-tractor Assembly Considering the Effect of the Supporting Surface Profile

Results of theoretical studies of dynamics of the machine-tractor assembly taking into account the influence of a bearing surface profile were presented. It was established that in the course of operation, the machine-tractor assembly is exposed to a number of external factors leading to a change of vertical loads on the chassis and the engine. Mathematical models of dynamics of a tractor and a machine and a tractor unit consisting of a tractor of pivotally connected arrangement and a trailed sower were constructed. Such models make it possible to study dynamics and oscillatory processes of multi-element units. A mathematical model of tractor wheel dynamics was formed. Speeds and angles of orientation of elements of the machine-tractor assembly in space were determined. Influence of profile of the bearing surface on the unit elements when moving in the field prepared for sowing and the field after plowing was calculated. Theoretical studies of the influence of the bearing surface profile on dynamics of the machine-tractor assembly were performed on the example of KhTZ-242K tractor and Vega-8 Profi sower (Ukraine). When moving, the sower frame has a smaller amplitude of vibration accelerations than that of the tractor. Accordingly, the tractor has higher oscillation energy because it rests on the ground through its wheels having appropriate stiffness. The sower moves with its working bodies immersed into the soil which leads to a decrease in the amplitude of oscillations. The highest energy of amplitude of oscillation accelerations of the sower frame in the vertical direction was observed at frequencies of 15.9; 23.44; 35.3 and 42.87 Hz. It was found that the increase in working speeds of agricultural units leads to the fact that oscillations of all components reach significant values. This entails an increase in dynamic loads on soil and, as a consequence, its compactio

Estimating the Dynamics of A Machine-tractor Assembly Considering the Effect of the Supporting Surface Profile

Results of theoretical studies of dynamics of the machine-tractor assembly taking into account the influence of a bearing surface profile were presented. It was established that in the course of operation, the machine-tractor assembly is exposed to a number of external factors leading to a change of vertical loads on the chassis and the engine. Mathematical models of dynamics of a tractor and a machine and a tractor unit consisting of a tractor of pivotally connected arrangement and a trailed sower were constructed. Such models make it possible to study dynamics and oscillatory processes of multi-element units. A mathematical model of tractor wheel dynamics was formed. Speeds and angles of orientation of elements of the machine-tractor assembly in space were determined. Influence of profile of the bearing surface on the unit elements when moving in the field prepared for sowing and the field after plowing was calculated. Theoretical studies of the influence of the bearing surface profile on dynamics of the machine-tractor assembly were performed on the example of KhTZ-242K tractor and Vega-8 Profi sower (Ukraine). When moving, the sower frame has a smaller amplitude of vibration accelerations than that of the tractor. Accordingly, the tractor has higher oscillation energy because it rests on the ground through its wheels having appropriate stiffness. The sower moves with its working bodies immersed into the soil which leads to a decrease in the amplitude of oscillations. The highest energy of amplitude of oscillation accelerations of the sower frame in the vertical direction was observed at frequencies of 15.9; 23.44; 35.3 and 42.87 Hz. It was found that the increase in working speeds of agricultural units leads to the fact that oscillations of all components reach significant values. This entails an increase in dynamic loads on soil and, as a consequence, its compactio

Пуриновые и глюкокортикоидные рецепторы у детей с бронхиальной астмой и хроническими бронхолегочными заболеваниями, сопровождающимися бронхообструктивным синдромом

Using radioligand method has allowed to find out that the children suffering from bronchial obstructive diseases demonstrate the purine receptors disorders expressed in increase A1/A2 receptors ratio. This ratio is reliably higher in bronchial asthma children than in children with asthmatic or recurrent bronchitis, chronic pneumonia and Kartagener’s syndrome as well as in adult bronchial asthmatic patients. Children with Kartagene r's syndrome have reduction in binding ability of glucocorticoid receptors and compensatory increase in their concentration. Theophylline therapy leads to decrease of A1/A2 receptors ratio. This fact correlates to the improvement in the value of forced expiratory volume for 1 second.С использованием радиолигандного метода обнаружено, что у детей с бронхообструктивными заболеваниями отмечаются нарушения пуриновой рецепции, выражающиеся в повышении соотношения количества А1/А2 рецепторов. У детей с бронхиальной астмой это соотношение достоверно выше, чем у детей с астматическим или рецидивирующим бронхитом, хронической пневмонией и синдромом Картагенера и у взрослых больных бронхиальной астмой. У. детей с синдромом Картагенера отмечается снижение связываю щ ей способности глюкокортикоидных рецепторов и ком пенсаторное увеличение их концентрации. Терапия теофиллином приводит к снижению соотношения количества А1/А2 рецепторов. Этот факт коррелирует с возрастанием объема форсированного выдоха за первую секунду

Determining the Effect of Formulation Components on the Physical-chemical Processes in a Semi-finished Flour Whipped Product Under Programmed Changes in Temperature

The method of a differential thermal analysis has been applied to investigate the physical-chemical and chemical processes that occur in a semi-finished whipped flour product under conditions of a programmed change in temperature. Qualitative assessment of the processes that take place in the examined samples during thermal transformations has been performed.We have explored the influence of formulation components of a semi-finished whipped flour product on mass losses, the rate of transformations, and the dehydration processes occurring under non-isothermal conditions at a constant heating rate of 10±1 °C/min while heating up to a temperature of 300 °C.Synergetic interaction between xanthan and gelatin has been confirmed. It was established that the introduction of a xanthan solution to a gelatin solution, the base of a semi-finished whipped flour product, improves structure and enhances its thermal stability during heating. It is likely that this occurs due to the redistribution of associated and non-associated hydroxyl groups, which contributes to forming a large number of inter-molecular hydrogen bonds.We have proven the catalytic effect of the enzyme transglutaminase in the system gelatin-xanthan on the interaction between the amino groups of lysine and the γ-carboxyamide group of glutamine residues bound by a peptide bond. This effect ensured a higher level of crosslinking the macromolecules of a protein framework and substantially slows down the dehydration process in a semi-finished whipped flour product.Our study has established minimum losses of the adsorption-bound moisture in semi-finished whipped flour product, which is likely due to an increase in the degree of binding the groups of -ОН and flour proteins, which predetermines the formation of intermolecular hydrogen bonds with the proteins of a gluten complex.The influence of xanthan, sugar, transglutaminase enzyme, flour, on the ranges of dehydration has been investigated, which depend on different forms of moisture binding in a semi-finished whipped flour product. We have determined the temperature intervals of moisture loss at different shapes and binding energy in a semi-finished whipped flour product.The results obtained have practical significance for establishing the rational temperature conditions for baking a semi-finished whipped flour product, namely 140±5 °