The choice of the method of force calculation of building structures is preceded by an analysis of the static determinacy and immutability of the rod system using structural formulas, while for different types of structures - for beams, trusses, frames, arches, etc. - sources offer different formulas. It is shown that for the structural analysis of all rod systems it is sufficient to determine the degree of structure anomaly using the formula of P.L. Chebyshev. The development of the linear-monad theory of structure makes it possible to formalize the dependence of the number of rods and hinges on the number of external and internal contours in the synthesis of both normal and anomalous structures

Keywords: beam, truss, frame, arch, structure, analysis, synthesis, immutability, definability, degree of anomaly, rods, system, contour, monad, hinge

The object of the development is an experimental installation with pulsed circulation of the coolant in the main circuit for its use as a hydraulic drive of a diaphragm pump used for pumping liquid in the secondary circuit, which increases the energy efficiency of the pump drive for small-scale energy facilities. An installation with pulsed circulation of the coolant with a diaphragm pump was developed, assembled and tested on the basis of a new design of the shock unit with a cam profile, which makes it possible to create an acceleration of the flow at the pump suction. As a result of the experiment, we obtained the dependence of the volume of the pumped liquid on the frequency of operation of the shock unit.

Keywords: energy efficiency, diaphragm pump, shock unit, pump drive, cam, fluid flow, fluid pressure, oscillation frequency

In article dependences of resistance are investigated on drove the planetary mechanism from the operating moment on the central wheel. The hypothesis about active and jet components of mechanical resistance is offered in compliance with a method of electromechanical analogies. Results of pilot studies of the adjusting characteristic of the generator of the moment confirming theoretical provisions are presented.

Keywords: moment generator, adjusting characteristic, electromechanical analogies, jet resistance