In case for nuclear power plants long-term service operation over their design life, it is necessary to calculate reactor pressure vessel (RPV) strength and durability acknowledgment (static strength, strength under cyclic and seismic loads, brittle fracture resistance (BFR) include) the as one of the most important NPP structure. Usually, according to the brittle strength assessment, RPV resource is determined, that is, time of its subsequent safe operation. The purpose of this work is assessed BFR RPV at potential emergency accidents (EA) using the Ukrainian warm pre-stress approach. The calculated thermohydrodynamic parameters at EA were used to calculate the stress-strain state of the developed reactor finite element (FE) model. For researching, the most indicative scenarios were selected: where reactor is cooled at a high pressure. In RPV FE model cracks are modeled at the most dangerous places - welds and nozzle. Stress intensity factor (SIF) distribution along crack front and temperature for the most dangerous accidents in terms of BFR are presented in figures. Brittle strength condition is ensured during the nuclear power plants service operation for up to 60 years, which is more than 1.5 times more than the oldest Ukrainian power plant with VVER-1000. For some emergency accidents, warm pre-stress really significantly increased RPV safety margin, but for the most dangerous accidents, the results are the same as without taking into account WPS.

Purpose is to evaluate experimentally and theoretically a mechanism of solid media fracturing by means of explosive charges varying in their cross-sectional shapes. Methods. The Mohr-Coulomb strength condition has been applied to describe rock transition to the disturbed state. The condition has become a basis to develop a mathematical model of explosion (i.e. shock and detonation wave) of the concentrated borehole charges. The simulation explosion was modelled while adequate load applying at the points belonging to the outline of both cylindrical charge and at the charging angles in the shapes of triangular and square prisms. The evaluation mechanism of solid media fracturing by means of explosive charges, varying in their shapes, used the models made of optically active materials. A method of high-speed photorecording of the process was involved; the method was combined with the photoelastic technique of stress analysis. Findings. Taking into consideration rock transition to the disturbed state, the Mohr-Coulomb strength condition was applied with the possibility to simulate failures resulting from shear as well as from separation according to the developed mathematical model. The calculation results have helped identify distribution of a geomechanical parameter (Q) at different time points (time iterations). Dependencies of changes in the maximum component of the main stress tensor σ1 / γН along the axis passing through the charge centres perpendicularly to its flat surface for different time iterations have been developed. It has been defined that the maximal stresses are concentrated on the top of both triangular and square prisms helping shape a denser crack network within the zones. Originality. It has been identified that at the initial explosion stage, the maximum values of the main stress tensor component σ1 / γН along the axis passing through the charge centre perpendicularly to its flat surface, experience certain change depending upon a power law with the increasing distance to the charge outline. At the same time, if the charge is of a square prism shape then time iteration being i = 5 makes the main stress decrease according to a linear dependence. Practical implications. The research may be used as the basis for the development of rational parameters of the resource-saving methods applied to separate hard complex rocks in terms of open pits where building materials are mined.

Aus den Silanen (I) und Trialkylstannanol oder Trialkylalkoxystannan (II) werden die Substanzen (IIIa)‐(IIId) hergestellt.

The work is devoted to the research of sources of risks of formation and management of human resources of the company and the development of a project of an information system to minimize the risks of dismissal. Existing approaches to employee incentives and programmatic decisions on the human capital accounting are described. This work analyzes the most famous modern information systems for monitoring and management of personnel. A target tree has been built to address the current problematic situation. Alternative means for the realization of the project of the information system considering the peculiarities of the scope are considered. The hierarchy of the general purpose of choosing the optimal means of implementing the information system for minimizing the risks of personnel management is presented. Using the method of analytical hierarchy, the priorities of alternatives relative to the focus are calculated. The most appropriate project implementation for such a system is to use the WordPress platform. A complex of UML diagrams was developed for the project implementation. The structure of the project in the form of WBS is given. Gantt chart, which shows in detail the schedule of information system design. To track all possible deviations of the project, the critical path of the project is calculated. The prototype information system for minimizing the risks of dismissal of workers runs on an Apache Web Server using MySQL as a database. The design was based on a suite of tools for creating WordPress sites and web applications. The project of the information system implements the policy of identification and management of risks associated with the outflow of valuable employees, describes and allows to regulate the procedure of identification and accounting of employees who are the sole owners of project knowledge. It also defines the sequence of steps that make it impossible to incur the risks associated with the outflow of staff, complicate, and/or slow down the process. The information system in the field of software development, database design, and support of existing information systems is offered.

Durch Anlagerung der Silane (I) an die Silylester der Acryl‐ und Methacrylsäure (IIa) und (IIb) erhält man die Silyl‐acyloxysilane (III).