Studies of the instrument error depending on the compaction of the grain sample in the sensor with free backfilling, forced sealing with a piston and under vibrating showed that the highest reproducibility of the readings, and therefore the lowest instrument error is provided, when exposed to vibration. Granular bulk materials change the volume only to a limited extent, even under the influence of external forces. The vibration action significantly reduces these forces, allowing the grains to be stacked more tightly. The stacking density depends on the vibration parameters. The use of vibration allows the stabilization of the volume density and simultaneous grain transportation through the sensor cavity. To use this method of preparing a grain sample, it is necessary to study its electrical specifications with this type of transportation. The vibration amplitude can be modified by changing the supply voltage of the electromagnetic vibrator. In this work, the dependences of the grain dielectric constant of different humidity in a high-frequency electric field on the vibration amplitude acting on it, are investigated. To determine the analytical expression that relates the grain electrical specifications with its moisture, volume density, temperature and frequency of the electric field, methods of active experiment planning are used in the work. Regression analysis of the experiment model showed its adequacy. Тhe results are required and can be applied, for example, in the development of in-line and discrete grain moisture sensors.

A detailed analysis of the end-to-end conductivity was carried out using experimental data from the measurement scheme, presented in the article. The oscillograms of changes in the time of the specific active conductivity of wheat grains of the given moisture at a given amplitude of vibration (on a direct current) were removed. Experiments have shown, that specific active conductivity varies from a value corresponding to a lack of vibration to a corresponding value, subject to vibration, i.e., almost more than 3 times. The minimum value of end-to-end conductivity when exposed to vibration, as shown by the experimental test, is almost an order of magnitude less than its average value. The decrease in the value of end-to-end conductivity relative to its average value is manifested in the intervals of time corresponding to the moments of movement of the sensor downwards, that is, in the direction of acceleration of gravity, under the influence of a vibrator. The work offers a way to measure the moisture of the grain mass and the device for its implementation. A distinctive feature of the developed method is that the controlled grain mass is filled in the cavity of the capacitive sensor and subjected to vertical vibration. The registration of dielectric permeability (moisture) is made at intervals of time corresponding to the minimum value of end-to-end conductivity. The proposed method makes it possible to significantly increase the accuracy of measuring the moisture content of the grain mass. This is especially important in conditions of high moisture.

No abstract

Improvement of the design of the sample preparation device for bulk materials during the flow control of their moisture content, based on the use of the vibrating process to stabilize the bulk density, will ensure continuity of the flow of bulk materials. The accuracy of humidity measurement will be increased by using dielectric metric methods due to the decrease in the through conductivity of loose materials, which is associated with the rupture of contact bridges between their particles in the vibrating mass. An analysis of the results of an experimental study of bulk materials in a vibrating state shows that the use of such a grain state is advisable for the following reasons. Firstly, at a constant vibration amplitude, the bulk density of the grain mass stabilizes, and secondly, it's through conductivity sharply decreases, which is explained by the ruptures of contact bridges between the particles in the vibrating fluid mass of bulk material. Combination of the process of vibration for the purpose of stabilizing the bulk density of bulk material with its simultaneous transportation through the cavity of the vibration chamber is carried out in the device proposed by the authors. In order to ensure the stabilization of the bulk density of bulk material, a device has been new developed.

Application of mathematical methods of cost optimization for repair and maintenance of electrical equipment of agro-industrial enterprises is one of the important and promising directions for increasing the efficiency of electrical equipment operation management in agriculture. Mathematical programming systems use graphical and related attributive information in solving optimization problems. As graphical information in these systems we used maps, plans, diagrams, schedules of preventive measures from which the list of equipment for certain types of repair and maintenance, their labor intensity for individual objects, types of equipment and in total for the enterprise are established. Databases of electrical equipment are used as attributive information to describe electrical equipment of agro-industrial enterprises. Due to joint processing of graphical and attributive information in optimization systems, all stages of work with spatial data are more operative. Beginning from spatial data search, selection and analysis we can make a specific decision during the operation control of electrical equipment. This article considers maintenance and repair operation (MR) as a task of mathematical programming with cost optimization and deals with three approaches to the organization of this task. The expediency of using each method of solution is analyzed. The structural schemes, equations describing mathematical models, advantages and disadvantages of the presented models are given. We marked prospect of using linear programming programs for the decision of the given optimization problem by means of the inverse matrix method, i.e. the modified simplex method and computing algorithm with a standard sequence of operations.