Based on the analysis of current developments in small hydropower plants, the structural scheme and installation scheme of a dam without hydropower were developed. According to the developed scheme, a small hydroelectric power plant was installed and prepared for testing. During the study, an analysis of 3 magnitudes (V), voltage frequency (Hz) and sinusoidal coefficient (%) that determine the quality indicators of electricity was presented. The obtained results are compared with the value limits given in the international standard normative document.
The article recommends automatic control of active ventilation systems in agricultural product storage facilities. The search for rational solutions for ventilation, heating, and automatic control systems (ACS) that improve product storage quality and methods and means of storage is considered.
As a result of the analysis of the requirements for air-cooling storage units that operate for no more than 25 days per annual storage cycle, it was proved that refrigerating arrangements that are based on the principle of operation of vortex energy separators - vortex tubes (VT) meet these requirements most fully. In terms of temperature effect, the VT is inferior to the expander by 1.3 ... 1.5 times, in terms of cooling capacity by 3.0 ... 3.5 times. Compared to the throttling process, vortex tubes, when operating in air, are about 30 times better in terms of temperature effect and 15 times better in terms of cooling capacity.
The paper presents an analysis of the dynamic response of an underground main pipe under the action of longitudinal wave, propagating in soil along the pipe. The outer surface of the pipeline is in contact with soil along the pipeline axis according to the elastic- viscous law, and the ends of the pipeline are connected to massive nodes by elastic elements. Using the Fourier method, an analytical solution to the problem of longitudinal vibration of an underground pipeline, pliantly fixed by nodes at its ends, is obtained. The problem of longitudinal vibration of an underground pipeline with visco-elastically fixed nodes at the ends is solved numerically. Longitudinal wave in soil is taken as a traveling sine wave. The paper presents a comparative analysis of the results for some values of seismic wavelengths, the ratio of the wave propagation velocity in soil and in the pipeline, the coefficients of elastic and viscous interaction. The viscosity coefficient of interaction at the "pipe-soil" system contact leads to attenuation of the wave front in the underground pipeline. For soils, the values of the viscous interaction coefficient of more than 100 kN⋅s/m2, may lead to complete attenuation of the bursts at the wave front in the pipeline.
This paper analyzes the dynamic response of a wave propagating to the soil horizontally through a pipe. That is, the state considers a linear viscoelastic model of the interaction of the "pipe-soil" system. This problem is solved using the numerical method of differential equations. The longitudinal wave in the ground is taken as a sinusoid. And also, in the article, we will compare the comparative analysis of the results for some values of the coefficients of elasticity and viscosity of taste, propagation velocity, and pulse duration. In the current flow of the "pipe-soil" system, reflections of waves propagating in an underground pipeline at the boundaries of the pipeline, usually propagating in soils. This leads to a change in the shape of the underground pipeline, the value of which can double. The viscosity coefficient of interaction at the "pipe-soil" system contact leads to attenuation of the wave front in the underground pipeline. For soils with values of viscous interaction coefficient more than 100 kN·s/m2, this may lead to complete attenuation of the bursts at the wave front in the pipeline. The ratio of steps along the coordinate and time equal to the propagation of waves in the pipeline, obtaining results that coincide with the exact nature.
Building a macro and micro model of a multistage process is considered using the decomposition method, dividing the general technological system into interconnected control loops. A procedure for constructing an integrated macro model of a multistage process using a system of material balance equations for each control loop, a two-level mathematical model of a complex multistage system, developing principles for modeling and systematizing element models, the degree of aggregation, in general, controlling the technological properties of a material resource, calculating the schemes is reduced to solving a system of algebraic equations, modern technological scheme processing of a material resource, the procedure for constructing an integrated macro model multistage process (SME). A modern technological scheme for processing material resources cannot be carried out without returning circulating products when the product from subsequent nodes is sent for revision to the head of the technological scheme. The procedure for constructing an integrated macro model of SME s at two stages is considered. The task is to find the optimal solutions to the original mathematical model by interconnecting conditionally - optimal solutions of individual models. A comparison of various formal decomposition methods is performed according to previously determined criteria, and on this basis, the most preferable is chosen. When modeling multidimensional systems, one has to operate with various factors that have different units of measurement. Therefore, it is advisable to determine the dimensionless mathematical model since it is easily analyzed. The use of the latest mathematical modeling tools and modern methods of the flexible equation mainly determines the prospects of such studies.
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