Volume 29, Nº 4 (2019)

Introduction. The model of a given structure should be identified based on the results of solving the problem of parametric identification. This model should provide the best possible the database development reproduction of the experimental data. Therefore, the procedure for identifying such a model is subject to natural logic and includes the stages of data a determination of a set of acceptable models and subsequent selection of the best of them. If the set of acceptable models is large, the procedure for determining the best one can be time-consuming.
Materials and Methods. The set of acceptable methods in the problems of parametric identification largely depends on the type of the experimental data. Uncertainty for example, probabilistic and statistical methods are useful if the observed factors are random and subject to any law of probability distribution. If the conditions for the use of such methods are not met, it may be useful to present an approach based on identifying the boundaries of location of the model parameters that ensure the achievement of specified levels of quality characteristics.
Results. It is based on the use of maximum permissible parameter estimates and allows one to determining the set of parameter values that guarantee the achievement of the required qualitative level of experimental data description, including from the standpoint of analyzing the impact of changes in accord with requirements to the accuracy of their reproduction. 
Discussion and Conclusion. It is shown that the obtained value of the chemical reaction rate constant, in accordance with the introduced criteria, provides acceptable accuracy, adequacy, and stability of the identified kinetic model. At the same time, the results of calculations revealed the information that can form the basis for planning experiments carried out in order to improve the accuracy of the experimental data.

Introduction. Personnel of the highest scientific qualification are the basis of staffing the competitive development all sectors of the national economy of the Russian Federation. 
Materials and Methods. The article proposes a model for calculating the age-specific number of Candidates and Doctors of Sciences on the basis of annual statistical data on the number of defenses of candidate and doctoral theses and survival rates. Since the detailed data are presented only for the period starting from 2008, and the aggregated data are not known for all years, the corresponding interpolation methods are proposed to restore the missing data. 
Results. The results of the study are 6 models for calculating the number of Candidates and Doctors of Sciences, approximation function of the multiplicative survival coefficient for persons with scientific degrees, approximation functions of the age distribution of the applicants of degrees of Candidate and Doctor of Science, approximation functions of agerelated and cumulative distribution of the number of Candidates and Doctors of Sciences, quantitative estimates of the number of Candidates and Doctors of Sciences in 2019.
Discussion and Conclusion. The proposed models have shown their adequacy. As a result of the calculations, it was found that the number of Candidates of Sciences in the age category of 20–80 years is 468,000 people, and the number of Doctors of Sciences in the age category of 30–90 years is 72,000 people. According to the obtained numerical values, approximating functions were constructed to get the number of Candidates and Doctors of Sciences in any age range. Since the system of personnel of the highest scientific qualification is sufficiently inert, the data obtained of age structure of the personnel of the highest scientific qualification will retain its character for at least another 10 years.

Introduction. The article deals with the development of a device for evaluating technical condition on of volumetric hydraulic drives made in Russia and abroad at repair and service centres.
Materials and Methods. The study uses the statements of theoretical mechanics and hydrodynamics, the basic principles of mechanisms and machines production. For technical condition evaluating of volumetric hydraulic drives, the method of hydraulic loading of hydraulic motor was applied. Reliability of results was confirmed during experimental settings of the hydraulic loading device stand.
Results. A stand design with the hydraulic loading device was developed and put into practice for new technical condition evaluating of volumetric hydraulic drives, made in Russia and abroad, at repair and service centres. A property of the stand is the use of the hydraulic loading method when the torque (braking) moment on the shaft of the tested hydraulic rotor is created using a hydraulic machine. The stand consists of data processing and measurement units. The data processing unit is based on a multifunctional data acquisition board connected with a personal computer. The structure of the data measurement unit includes a frequency converter connected to an electric motor, a drive shaft for connecting the shaft of the tested hydraulic pump; hydraulic system having a hydraulic tank; suction, control, drain, and discharge lines and reversible flow chokes installed in discharge lines and connected with the hydraulic pump and hydraulic rotor; loading device with the reversible hydraulic pump, drive shaft joined with the shaft of the tested hydraulic motor. 
Discussion and Conclusion. The new stand design with the hydraulic loading device allows implementating of the dynamic testing methodology and guarantees high accuracy of evaluating the technical condition of the most widespread Russian and foreign volumetric hydraulic drives at repair and service centres. 

Introduction. Most of the territories where technical service enterprises are located in the agricultural-and-industrial complex, are high-quality agricultural lands. However, so far no analysis of the technological feasibility of using these land plots has been made. The goal of this work is to develop recommendations for the effective use of areas allocated for technical service enterprises, taking into account the increase in the density of development of territories through reconstructing of repair and service bases.
Materials and Methods. Determination of actual indicators of the development density for technical service enterprises and their compliance with the set of rules was carried out using the companies’ accounting documents and situational plans for repair and maintenance bases. In the course of the study, recommendations were developed for reconstruction of master plans to increase the development for density repair and maintenance bases of these companies.
Results. The results of studies of the actual development density of technical service enterprises have shown that in 65% of cases it is below the minimum development density established by the code of rules SP 19.13330.2011. The actual density maintenance bases is in the range of 5.1–66.0%. At the same time, the actual average density of development of enterprises of technical service for agricultural producers was 19.7%. The largest number of enterprises (61.9%) has the development density of 5–20%, that is, significantly lower than the standard value. The smallest number of enterprises (3.6%) have the development density in terms ecology of above 50%. Most enterprises have the green area less than 10%, which is lower than the regulated value. 
Discussion and Conclusion. We showed the low efficiency in the use of areas allocated for repair and maintenance bases of technical service enterprises in various areas of the agricultural- and-industrial complex of the Volga Federal District of the Russian Federation.

Introduction. The use of the equations of statistics and dynamics is insufficient to solve the problem of equilibrium of agricultural aggregates, and additional efforts are required that in turn significantly increases the complexity of relevant research. Known studies are characterized by the fact that when analyzing the stability of the tillage machine, on the basis of the equilibrium condition, a standard plow body is considered as a working body.
Materials and Methods. In this study, a variety of methods was used to determine equilibrium conditions for a system of converging forces in an analytical or geometric form. The equilibrium conditions were determined for the mounted five-case combined machine made soilless tillage. Analytical determination of the equilibrium conditions for the system was through the preparation of equilibrium equations. A graphical definition of the equilibrium conditions was obtained by constructing power polygons for vertical and horizontal projection planes.
Results. As a result, it was found that tillage machines have an excessive number of bonds (supports). There is defined a condition for the balance of forces acting on a tillage machine with working bodies for layer-by-layer subsurface tillage, having twelve connections: five field boards with two connections each and two support wheels one at a time, the perceivable responses from the interaction with which should be positive.
Discussion and Conclusion. According to the results, it is noteworthy that modern agricultural machines are multi-operation statically indeterminate systems. As a result, the process of their regulation during operation is complicated and it is practically impossible to make power calculations without accepting additional conditions. For simplification, accuracy and most visual representations, the problem was solved by analyzing closed force polygons, the construction method of which is presented for both the equilibrium conditions in horizontal and vertical planes.

Introduction. The justification of parameters and introduction of new environmentally friendly technologies and technical means for weed control in the stalk zone is a pressing issue of major economic importance. The aim of the study is to justify the effective modes of operation trailer machine for the hydraulic removal weeds on the industrial plantation of horticultural crops.
Materials and Methods. According to the analysis of existing technologies and technical means for weed vegetation removal from the stalk zone of garden plantings, a device for hydraulic removal of weed vegetation without the use of herbicides has been developed at Federal Scientific Agroengineering Center VIM. 
Results. The statistical analysis of the factor experiment data showed that the following operating modes of the device are the most effective for performing the technological operation of hydraulic removal weeds: the distance between the soil and the spray head is 14.5 cm, the working fluid supply pressure is 759 bar, the movement speed is 2.4 km/h. The static treatment mode for estimating the penetration depth of the jets with exposures of 10, 5, and 3 sec showed a penetration depth of 62, 34 and 12 mm, respectively. The diameters of the track were: In the first case 350 mm external and 330 mm internal (cutting width 24 mm); in the second and third cases – 340 mm for the outer and 328 mm for the inner (cutting width 16 mm).
Discussion and Conclusion. As a result of the experiment, it was established that the machine is able to provide high-quality processing stalk zone when using water from the central water supply. After the unit cultivated the soil, 90% which was covered with weeds, only 20–30% of the visible green mass remains, the rest is mixed with the soil.