JSC Federal Center for Geoecological Systems

Power system stability, understood as the ability to maintain synchronous operation of generators and ensure stable power supply to consumers under various disturbances, is a fundamental requirement for their design and operation. Of particular danger to dynamic stability are low-frequency electromechanical oscillations (LFOs) occurring in the range of 0.1–3 Hz. The prolonged existence of undamped (or weakly damped) oscillations of regime parameters can lead to a violation of oscillatory stability, cascading отключения of generating equipment, and, ultimately, to large-scale system авариям [1] .

Currently, patient safety is one of the most important areas of healthcare, and it requires global coordinated efforts. The term "patient safety" covers various aspects, including the prevention of errors and adverse events, minimising risks of infections associated with medical care, ensuring proper use of equipment and effective interaction between patients and medical staff. World Health Organization (WHO) as a specialized unit of the United Nations in the field of global health has a unique international position and authority. It collects and analyzes data from around the world, conducts research and consults member countries within its competence, including medical care safety. In the Russian Federation, the movement for patient safety is still in the process of formation, many medical organizations, when implementing modern principles of safe medical care, face a shortage of practical manuals and other methodological materials. This literature review is devoted to the analysis and systematization of WHO initiatives in the field of improving patient safety. The review pays special attention to WHO's practical recommendations for improving patient safety, which can be used in medical organizations. The review also provides an analytical assessment of the implementation of the main activities aimed to improve patient safety in the Russian Federation. Thus, this study will be interesting to a wide range of readers, especially health care managers and medical professionals who plan to implement the principles of safe medical care in their organizations.

For an electric power system (EPS), as a dynamic system with many inputs and many outputs (Multi Inputs Multi Outputs System − MIMO), compact analytical formulas are obtained for calculating the coefficients of the controller matrix and the observer matrix of the state of the solution of the synthesis problem, providing a given placement of eigenvalues along full state vector. These formulas are generalizations to MIMO systems of the well-known Ackermann formula used to design the control of systems with one input and many outputs (Single Input Multi Outputs System − SIMO). The approach is based on the transformations used in the original multi-step (multilevel) decomposition method, as well as a nondegenerate similarity transformation in the form of the Kalman controllability matrix. The obtained formulas are applicable to dynamic systems, for which the dimension of the state space is a multiple of the dimension of the inputs (controls). This limitation is removed by using the Yokoyama transform. These formulas differ in terms of parameterization of the set of equivalent laws. An example of the synthesis of a control law for a synchronous generator in a complex EPS is considered in order to preserve the existing modes of electromechanical oscillations and meet additional requirements (roughness with respect to disturbances and/or increased sensitivity to changes in controlled parameters in a given region or frequency band).

The accident rate of overhead lines (OHL) of the Unified National Power Grid (UNEG) of the Central European part of the country over the past 15 years has been subjected to statistical analysis. A comparison of the values and structure of the failure rate (failure frequency) of 220 and 500 kV overhead lines with a length of about 9 and 27 thousand km, respectively, is carried out. It is shown that the last decade has been characterized by the most favorable accident rate characteristics of OHL. At the same time, there is a tendency when the failure rate of the overhead line becomes little dependent on the rated voltage of grid. This fact casts doubt on the belief of specialists that has existed for many decades, whereby with an increase in the rated voltage, the failure frequency of overhead line objectively decreases. The organizational structure of failures of 220 and 500 kV overhead lines is relatively stable from year to year: social (untimely identification and elimination of defects, the impact of unauthorized persons and organizations not participating in the technological process) and natural impacts (bird impacts, exceeding the impact characteristics of natural phenomena relative to designed conditions, the impact of recurring natural phenomena) approximately equally affect the accident rate of overhead lines. The revealed trend once again demonstrates the objective possibility of managing the reliability of electrical grid elements.

This paper presents the analysis of the role of cost inflation and time preference on the decision making of the producer. The basis for the analysis is the model of optimal control of production expansion. We demonstrate that in this framework, higher cost inflation leads to shorter investment period and longer period of no investment. The high discounting of the future also shortens the period of investment by the firm.

This work presents an extension of the model of optimal investment in production expansion. We introduce the possibility of having an account in a bank and reformulate the model of optimal control of production expansion to study the changes in the optimal behaviour of the producer as they face the trade-off between the risky entrepreneurship and risk-free bank account. The producer's problem is formalized as the optimal control problem which are solved using the Pontriagin's maximum principle and the Hamilton - Jacobi - Bellman equation.

This work presents the approach to solving the functional equation of non-local type that appears in the study of a stochastic optimal control problem. This experience demonstrates the challenges and possible solutions in the analysis of optimal control problems with Poisson uncertainty.

A mockup of the hardware-software system for monitoring accuracy parameters of magnetic field converters, such as a conversion characteristic, sensitivity, nonlinearity, hysteresis, trigger threshold, and others, has been developed. The calculated value of irregularity of magnetic field of the developed system is 0.5 - 0.6%. The maximum value of generated field magnetic induction is ± 58 mT. The increase and decrease of magnetic field magnitude is produced in minimal increments of 0.4 mT. The scheme of operation of the system, the software and the measurement process are observed.

The geochemical composition of waters of the Mzymta River is subjected to sharp seasonal changes. In summer, the waters are enriched in 34 elements (mainly REE, Fe, Mn, Cs, Al, and Cd) relative to their average contents in river waters. REEs in the waters show steady relations MREE > HREE > LREE with a general positive trend to the mouth. In spring, they are enriched only in 14 elements. They have the poorer REE composition and less fractionated REE patterns. In summer, their contamination significantly increase relative to MPC, with growth from the upper reaches to the river mouth. A general geochemical specialization of bottom sediments is determined by 27 elements, contents of which insignificantly exceed their average contents in rocks exposed in the basin for the upper continental crust. Disagreement between the high level of water contamination in summer and a weak contamination of the bottom sediments of the river is related to the low contents of finely dispersed mineral and organic matter in the latters. It was determined that chemical elements are supplied in water from three main sources: natural, natural–technogenic, and anthropogenic–technogenic. The maximum contribution to the water contamination over the entire river extent is provided by natural sources: rocks that compose the basin. The anomalous increase of concentrations of chemical elements, including Th and Y, in the middle and lower reaches of the river is related to the natural–technogenic sources at the adjacent slopes of the valley. These are technogenic areas and talus, as well as highway and railway roads, and sometimes building embankments, which are made up of disintegrated rocks devoid of soil–vegetation layer. The anthropogenic–technogenic factors make only a limited contribution to the contamination of water and bottom sediments of the river. The radioecological state of waters and bottom sediments of the Mzymta River is safe.

It is of great interest to determine the uniformity of heating in coke ovens. Current measurement methods are described. The deficiencies preventing their use for the regulation of coke heating are discussed. A new method is proposed on the basis of telemetric equipment determining the temperature over the height of the heating channels. This method is simple to use: within a single shift, the temperature distribution over the height of all the heating channels in several walls may be assessed. The pace of the measurements is increased because the equipment does not need special cooling before repeated use. In industrial conditions, this method is used to measure the wall temperature of the heating channels in coke ovens. These experimental results are compared with the theoretical equations proposed in the previous part of this research. The results confirm the proposed mechanism of the process, which is fully consistent with the industrial temperature distribution over the height of the heating channel (except for the hearth temperature). In addition, the results emphasize that the general model must take correct account of the composition of the heating medium (a gas–air mixture)—primarily its air excess.