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Today, an urgent and unresolved issue is the study of transport operations that are used in the agricultural sector, because there is a problem when studying the movement of a machine-tractor unit with trailed or semi-trailer units. This is directly related to the increase in energy saturation of wheeled tractors and, as a result, an attempt to maximize vehicle performance. The study of transport work in the transportation of liquid cargo is of great interest, where an increase in cargo transportation leads to significant instability in the operation of a wheeled tractor and a tractor tank (which is devoid of internal partitions) due to natural vibrations of the liquid. This process leads to longitudinal and lateral instability, contributes to an increase in both dynamic characteristics and emergency situations (there is an effect on the smoothness of movement, vibration load, handling and stability of the vehicle, increasing the dynamic load of the undercarriage, etc.). Therefore, to confirm the theoretical aspects of the influence of fluid oscillations in the tractor tank, experimental studies are necessary. The experimental research methodology presented in this article will allow us to determine the dynamic characteristics during transportation of trailed and semi-trailer tractor tanks during steady-state movement, as well as in transient operation modes. The practical significance of the work is to obtain experimental data on the accelerations of the studied objects at different height filling of the liquid level in the tanks.

Practical application of the radio-holographic method for measuring the characteristics of antennas, especially when conducting acceptance testing of systems, requires an adequate assessment of the errors in the recovery of long-range characteristics. These errors appear to be a superposition composed of various sources, having different nature, different time characteristics and different degrees of influence on the final result. The purpose of this work was the development of a practical technique for determining the influence of random errors in measuring the amplitude-phase distribution of the field of the antenna required for the accuracy of restoring long-range characteristics (primarily the antenna pattern) of the antenna, the proposed technique being based only on processing the experimental results obtained with this measuring complex.A practical method for determining the influence of random errors in measuring the amplitude-phase distribution of the field of the antenna under study on the accuracy of restoring its long-range characteristics (primarily the directional pattern) on the basis of correlation and spectral analysis has been developed and experimentally confirmed. The main advantage of the developed method in comparison with the use of mathematical modeling is that the estimation of the accuracy of the reconstruction of the directivity diagrams is based on the results of processing experimental data obtained on a specific measuring complex and does not a priori impose any preliminary requirements on the statistical parameters of errors. The developed procedure for estimating the influence of random errors can be used to develop a methodology for metrological certification of measuring systems as measuring instruments.

Directional patterns measurement of antennas is carried out by the methods of far and near zone. Measurements in the far zone are straightforward; however they have a number of disadvantages. Near zone measurement methods are free from measurement shortcomings in the far zone, but it requires complex and expensive equipment for its implementation.Earlier, the authors have developed a concept of hardware and software modular design complex to determine antenna system characteristics as per measurements in the near zone. This concept assumes creation of a universal measuring complex to investigate various types of antenna systems with any type of measurement surface (plane, cylinder, sphere) in order to solve a wide range of applied problems. The purpose of this work lies in practical implementation of a variant of this measuring complex for measurement along the plane and determination of its metrological (hardware and software) capabilities.A working experimental sample of hardware and software complex for measuring the characteristics of antenna systems that realizes a radio-holographic method for measuring along a plane has been developed, created and practically tested. A preliminary estimation of errors in amplitude and phase measurements in the dynamic range of 45 dB and a comparison of the characteristics of several types of antennas measured in far and near zones have been made. Algorithms have been developed, a software for processing, storing and graphical display of measurement results has been created.

Measuring the amplitude-phase distribution of the radiation field of complex antenna systems on a certain surface close to the radiating aperture allows solving the problem of reconstructing the free-space diagram in the far field and also helps in determining the influence of various structural elements and defects of radiating surfaces on formation of directional diagram. The purpose of this work was to develop a universal hardware-software complex of a modular design aimed for determining the characteristics of wide range of antenna systems in respect of measurements of the amplitude-phase distribution of the radiation field in the near zone.The equations that connect the structure of radiation fields of the antenna system at various distances from it in planar, cylindrical and spherical coordinate systems as well as structural diagrams of the hardware part of measuring complexes have been analyzed.As a result, the concept of constructing a universal hardware-software complex for measuring the radiation field of various types of antenna systems with any type of measurement surface for solving a wide range of applied problems has been developed. A modular structure of hardware and software has been proposed; it allows reconfiguring the complex rapidly in order to measure the characteristics of any particular antenna system at all stages of product development and testing, and also makes the complex economically accessible even for small enterprises and organizations.

Experimental study of underground polymer pipes under temperature effect is developed in this paper by the method of centrifugal modeling to study the process of polymer pipes elongation depending on the depth of laying and physical and mechanical properties of soil. The method is based on the use of centrifugal installation with PC and software. The experiments were carried out in a centrifuge with an effective radius of centrifuge rotation at a working scale of modeling n = 40. Experimental studies were carried out at various laying depths of the underground polymer pipes. In the process of conducting experiments, the polymer pipe model was subjected to various temperature influences. The temperature effect on the polymer pipe model was created using an electric spiral. As a result, it is established that the process of polymer pipes elongation over time under soil pressure and temperature factor has a non-linear character; the value of the absolute strain depending on the laying depth and the temperature factor may differ by several times.