The article presents special characteristics of mathematical modeling of the process control a resource efficient heat supply system of industrial buildings and facilities, where constant temperature maintenance is especially critical for the process. A functional diagram of the operation of the continuous heat supply process is provided. The dependence of temperature at the point of heat-transfer fluid mixing on environmental is analyzed and control system operation algorithm is proposed.

Method and results of determination of strength and deformation characteristics of heavy concrete at static loading to the specified stress level, followed by high-speed loading with dynamic load, are presented. The process of testing a series of concrete samples of one strength class is described to obtain the performance characteristics of concrete at static, dynamic and static-dynamic loading. Comparative analysis of the obtained experimental data was carried out under different loading modes of prototypes. It was established that during dynamic and static-dynamic loading there is an increase in the level of relative stresses corresponding to the beginning of concrete dilatation by 20-30% relative to the results of static tests. The obtained experimental results are of interest for solving problems related to the problem of survivability of buildings and structures and their protection against progressive collapse, in particular in determining criteria of strength and deformability of concrete at a special limit state.

The article touches upon the problem of physical modeling of fishing twisted filamentary materials, in particular, the justification of the rules of similarity of relative longitudinal, bending and torsional stiffness of filamentary parts. The formulation of the problem is associated with the difficulties of conducting full-scale experiments for designing new fishing gear, as well as with the lack of systematic experiments on measuring the stiffness of synthetic cordage. In connection with this, it becomes necessary to conduct model experiments related to physical modeling of dynamic processes occurring with the cordage under load. There has been calculated the coefficient of proportionality of bending stiffness that determines the ability of filamentary parts and cordage to resist bending. There have been given the formulas that determine the combination of the ratio of bending stiffness to longitudinal stiffness and the dimensionless combination of the ratio of bend-ing stiffness to torsional stiffness. The study allows to predict the behavior and basic properties (di-ameter, density, strength, elongation, etc.) of modern synthetic filamentous fishing gear at the stage of their creation (design).

The paper analyzes the connection diagrams and operation of buildings heat supply systems, taking into account the impact of changing weather and climate influences during the heating season. High-quality central heat consumption control was carried out, at which the heating carrier flow rate was maintained at a constant level, and its temperature varied according to a predetermined schedule. Thermal characteristics or mode of operation of the building differed from the data set in the schedule, as a result, more heat was consumed in certain periods. Its overrun was also observed during the warm period of the heating season, when, due to the maintenance of the hot water temperature at the right level on the outlet from the water-heaters, the heating carrier from the source was supplied with a temperature exceeding the established norms. The results of field tests and the diagrams of heat supply for heating at the heat supply operation in central heating points are presented. The main accent is made on the study of multi-circuit heating systems with frontal control of heat supply.

The article considers the problems of physical modeling of twisted filamentary parts of fishing gear and the similitude rules of bending stiffness of filamentary gear parts (FP). The problems are caused firstly by the scope, high costs and complexity of engineering structures in commercial fishery, and thus it was impossible to use them in full-scale testing. Secondly, the lack of systematic experiments prevented from measuring the bending stiffness of synthetic rope parts of fishing gear (SRP). Thus, it becomes necessary to conduct model experiments related to physical modeling of dynamic processes occurring in twisted fishing gear, as well as to carry out a detailed study of the theory of similarity. An attempt to evaluate the bending stiffness of a full-scale object made of polyamide (diameter = 10 mm, the object length and pin diameter were found using large-scale physical characteristics) based on the analysis of experimental data on bending stiffness of synthetic filamentous gear parts made of polyamide with different diameter and length (length = 0.08; 0.10; 0.12; 0.16; 0.20, 0.24 m and diameter = 1.10; 2.0; 3.10; 4.0; 5.0, 6.0 mm) defined on the pins with diameter = 2.0, 10.0 and 30.0 mm. The obtained data will help to prove the correctness of using the theory of dynamic similarity in the course of justification of similarity rules of bending stiffness of the large-diameter cordage and to determine the basic physical and mechanical properties necessary for modeling industrial fishing gear.