The development of methods for calculating structures made of ultra high-performance steel fiber-reinforced concrete (UHPC) in terms of strength and deformations is an important step towards the introduction of this innovative material into the practice of design and construction. This paper presents the results of finite element modeling of the operation of UHPC I-beam in the area of action of shear forces. The SMM model integrated in the OpenSees framework application is used for the walls of beams under conditions of flat stress. The authors have added new classes of materials that implement the averaged deformation laws of UHPC (with and without fiber) and the reinforcement placed in it. The calculations showed good convergence with the authors' own test results of the UHPC I-beams, as well as with the results of experiments by other researchers.

Keywords: shear strength, shear force, ultra high-performance steel fiber-reinforced concrete, I-shaped beams, OpenSees

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 presented article analyzes modern ways of qualitative assessment of agricultural territories in order to identify the existing principles to order and assess the prospects of development of such territories within the projected boundaries of rural network structure (rural agglomeration). The hypothesis about the key principles to which the ways of qualitative assessment of territories for the purposes of its urban development within the rural agglomeration should be prepared is presented.

Keywords: rural network structure, rural agglomeration, qualimetric landscape method, functional belonging criterion

This work is devoted to the study of the possibility of determining heart diseases on the basis of 13 categorical and numerical signs. We present a detailed analysis of the dataset, including dividing the data into training and test samples, dividing features into numerical and categorical, applying 4 different classification algorithms, checking the quality of the model using two techniques – delayed sampling and cross-validation. To assess the quality of the model, we pay attention to the value of the recall metric and the error matrix built on the test dataset from the deferred sample or on each test fold when using cross-validation. The results of the study are important both for a deep understanding of the relationship between certain medical indicators and heart disease, and for the development of effective methods for predicting them in the presence of individual symptoms.

Keywords: cardiovascular diseases, classification task, quality metrics, cross-validation, recall, machine learning, random forest

The paper provides a brief overview of publications on the application of mathematical modeling methods in the study of the patterns of functioning of hydroelectric power plants (HPPs). In particular, the following are considered: mathematical models of the total minimum water consumption for a cascade hydropower system in China; a mathematical model of hydropower plants; a mathematical model of two small hydroelectric power plants operating in tandem; accurate modeling of hydraulic transient characteristics in a complex drainage system. The task of filling in the gaps in the data concerning the operation of hydroelectric power plants is formulated. The approach to its solution is proposed to be based on the use of the method described in previous publications by one of the authors and based on the use of regression analysis apparatus. The specific task of filling in data gaps for a hydroelectric unit of one of the Siberian hydroelectric power plants has been solved. The following factors are used: active and reactive power of the electric generator, voltage, current and temperature of the stator iron, rotor current, air cooler hot air temperature.

Keywords: hydroelectric power plant, electric generator, data gaps, predictive analytics, regression model, adequacy criteria

3d-printing is the leading direction in world advanced technologies. For today 2614 patents were displaying in the Worldwide date base. General Electric is more effective companies in patenting materials for 3d-printing.

Keywords: materials for 3d-printing, review of patents