Technological peculiarities of cultivation and harvesting of some agricultural crops make it necessary to use asymmetric machine-and-tractor aggregates. However, for the time being there is no sufficiently complete, analytical study of the steady movement of such machine-and-tractor aggregates. This necessitates the development of a theory of stable movement of the aggregates which would allow choosing their optimal kinematic and design parameters. On the basis of the results of mathematical simulation, a system of linear differential equations of the second order is obtained describing transverse displacement of the center of masses of the aggregating wheeled tractor and turning of its longitudinal axis of symmetry by some angle around the indicated center of mass, as well as the deviation angle of the rear-trailed harvester from the longitudinal axis of the tractor at any arbitrary moment of time. This system of differential equations can be applied for numerical calculations on the PC, which will make it possible to evaluate the stability of the movement of the asymmetric machine-and-tractor aggregate when it performs the technological process.
Abstract. An air screen cleaning machine has been developed for the fractional technology of forage grain flattening with a new implementation of the elements of the screen part and a pneumatic system, allowing efficient separation of the grain material coming from the field after threshing by combine harvesters into fractions of the seed and the forage grain, and their qualitative cleaning from admixtures. There is presented a design and technological scheme of this machine, as well as its pneumatic system in the form of a pneumatic circuit. Research of the pneumatic system has been carried out by mathematical simulation, which makes it possible to theoretically test its operability and conduct analysis of the dynamic processes that occur in separate elements. By using the results of these studies, a possibility appears to design and then to make a test sample of the machine with the parameters of the working tools (the pneumatic system), which ensures a qualitative cleaning process from the admixtures of the grain fractions.Keywords: technology, fractionation, grain flattening, admixtures. IntroductionForage grain is valuable concentrated feed for animals, a source of carbohydrates, protein and other useful nutrients, and it is widely used in animal husbandry. To improve digestibility of its components, forage grain is subject to special processing, or grinding. One of the most economical ways of grain processing is flattening [1], which has a number of advantages in comparison with crushing [2-4], since it ensures the production of fodder best corresponding to the biochemical processes that occur in the stomach of the ruminant animal [5]. Despite the fact that grain flattening has been used for more than a hundred years, the machines for this process are constantly being improved in terms of the quality of the process performed, minimisation of the energy costs, etc.Analysis of the scientific, technical and patent literature on the existing technologies and technical means of the post-harvest handling and processing of grain forage [6][7][8] shows that one of the most promising and economically profitable technologies is the fractional technology of forage grain flattening. In order to isolate the forage grain fraction (which is then subject to flattening) from the grain that is arriving after threshing by the combine harvesters on the field into the post-harvest processing centres, an air screen cleaning machine in a new design of the elements of the screen part and the pneumatic system has been developed allowing not only efficient fractionation of the not yet treated grain into the seed grain and forage, but also qualitative separation of these fractions from admixtures.For this purpose the most perfect is the air-screen grain cleaning machine, intended for processing the grain material both in the usual mode (separation of grain from small, big and light admixtures), and in the fractionation mode (separation of the grain material into fractions with simultaneous cleaning of the grain fractions from admixt...
Abstract. Carbon (C), hydrogen (H), and oxygen (O) are the main chemical elements that determine the heating value of fuels. By combustion of biomass, C and H oxidize in an exothermic reaction. The carbon content in biomass is considerably higher (~45 %) than the hydrogen content (~6.5 %). In contrast, the heating value of H is approximately seven times higher than that of C. The more hydrogen per carbon, the lower the oxidation state and the more energy that will be released during the oxidation reaction, which is characterized by C/H ratio. In our study, the highest carbon content was detected in the mixtures (1/3) of tall fescue with osier (46.6 %) and reed canary grass with grey alder (46.9 %), whereas the lowest values were detected in the mixtures (3/1) of tall fescue with hybrid aspen (43.7 %) and reed canary grass with osier (43.4 %). The highest hydrogen content was found in timothy (5.93 %) and birch (6.83 %). In grass biomass, H content was on average 6 % lower than in wood biomass.
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