Probabilistic Modelling in Solving Analytical Problems of System Engineering

This chapter provides some aspects to probabilistic modelling in solving analytical problems of system engineering. The historically developed system of the formation of scientific bases of engineering calculations of characteristics of strength, stability, durability, reliability, survivability and safety is considered. The features of deterministic and probabilistic problems of evaluation of the characteristics of strength, stiffness, steadiness, durability and survivability are considered. Probabilistic problems of reliability, security, safety and risk assessment of engineering systems are formulated. Theoretical bases and methods of probabilistic modelling of engineering systems are stated. The main directions of solving the problems of ensuring security and safety according to the accident risk criteria are determined. The possibilities of probabilistic modelling methods in solving the problems of strength, reliability and safety of engineering systems are shown in practical examples

Investigation of the Ni3Al-Fe alloys by resistivity measurements and differential thermal analysis

A series of iron-doped Ni3Al ternary alloys is investigated by resistivity measurements and differential thermal analysis. Temperatures of phase transformations and disordering onset are determined. A hysteresis phenomenon is observed in the liquid state in polytherms of resistivity upon heating the alloy under study to the critical temperature. © 2013 Allerton Press, Inc

Simulation of the path shape fading memory in the theory of elastoplastically-deformed simple materials with initial loading surface

A mathematical theory of strict construction of reduced constitutive relations for Noll’s simple strain-hardening elastoplastic materials with an initial loading surface and a path shape memory fading during the active deformation was developed. The strains and the type of symmetry of the material properties are arbitrary. Constitutive equations were derived for materials without the path shape memory, for those with a weak fading memory, and with an n-th order fading memory. An elastic-perfectly plastic material is defined from the standpoint of the fading memory of path shape. The theory of strict construction of reduced constitutive relations for materials with a 1-st order fading memory of path shape for infinitesimal strains was developed on the assumption that the strain measures are small over the whole history. Special attention is given to isotropic materials

Development of double-layer anode material based on titanium nanotube for lithium batteries

Recently, considerable efforts of specialists in the field of power sources are aimed at research on fully 3D microbatteries. The key advantage of a 3D microbattery is the higher surface area as compared to a planar film that allows for increased contact area with the electrolyte and more surface sites available for reversible reactions with lithium ions. This in turn leads to improved battery kinetics and increased power density while maintaining a small areal footprint. This peculiarity of the battery design can be provided by the use of 3D structured cathode/anode materials, the most attractive of which are highly ordered nanotubes (NTs) made of titanium dioxide with high capacity at fast charge and discharge rates and excellent long-term cycling characteristics. Apart from this crucial result, key to the successful fabrication of a full solid state microbattery is the conformal deposition of electrolyte on the self-supported electrode material to preserve the 3D architecture

Numerical modeling of a dilution and transport of highly salty effluent in water bodies

The paper focuses on modeling of dilution and transport of highly salty effluent in water bodies. The modeling is made for three-dimensional unsteady regimes of turbulent mixing in the conditions of strong density stratification. Numerical results allow to determine the limits of applicability of two-dimensional hydrodynamic models and to estimate the maximal possible environmentally safe volumes of highly salty effluent disposal

Construction of constitutive relationships for simple in Noll’s sense materials with viscoelastic-viscoplastic behavior

Within the class of simple in Noll’s sense materials, the media with viscoelastic-viscoplastic behavior have been singled out, whose arbitrary deformations and types of symmetry in properties have been expressed by general constitutive relationships, in which the long-term fading memories of the deformation and time histories take place, and the approaches to their specialization have been developed.В классе простых по Ноллу материалов вы­делены среды с вязкоупруго-вязкопластическим поведением, для произвольных деформаций и видов симметрии свойств кото­рых построены общие определяющие соот­ношения с длительной затухающей памятью деформационной и временной историй и разработаны подходы к их специализации

Sewage treatment

The basic function of the wastewater treatment plant is to speed up the natural processes by which water purifies itself. In earlier years, the natural treatment process in streams and lakes was adequate to perform basic wastewater treatment. As our population and industry grew, increased levels of treatment became necessary before discharging domestic wastewater

Laboratory, Bench, and Full-Scale Researches of Strength, Reliability, and Safety of High-Power Hydro Turbines

Large hydropower plants (HPPs) are categorized as critically and strategically important infrastructure facilities in industrialized countries. Therefore, the issues of ensuring HPPs safety are of paramount importance. In this chapter, the basic aspects of the safety analysis of HPPs, calculation and experimental substantiation of the strength, and resource and reliability of the main equipment are discussed. The scientific and technical measures to ensure safety of HPPs are presented. As a defining measure of safety, it is proposed to ensure the protection of HPPs from severe accidents and disasters according to risk criteria. The main provisions of the risk assessment are presented on the basis of a sequential analysis of loads, features of stress-strain states, characteristics of mechanical properties, and limit states of hydraulic equipment of HPPs. The issues of calculation and experimental evaluation of hydro turbine’s resource, which limit the safety of HPPs, are considered. The features of technical diagnosis of hydraulic turbines are considered; characteristic defects and damages are described. The main provisions of the estimated residual life of hydro turbines are presented. The results of the risk estimates of HPPs and hydro turbine resource are given

Influence of Hydrodynamic Regimes on Mixing of Waters of Confluent Rivers

At present, a significant weakening of the intensity of transverse mixing at the confluence of large rivers, which is observed in a number of cases, is widely discussed. Since the observed features of the confluence of large watercourses are not only of research interest but also of significant economic importance associated with the characteristics of water management at these water bodies, a large number of works are devoted to their study. Water resources management requires measures for the organization of water use which can be rational only under the understanding of processes occurring in water basins. To explain the phenomenon of suppression of the transverse mixing, which is interesting and important from the point of view of ecology, a wide range of hypotheses is proposed, up to the negation of turbulence in rivers. One of the possible mechanisms for explaining the suppression of transversal mixing can be the presence of transverse circulation manifesting itself as Prandtl’s secondary flows of the second kind. The characteristic velocity of these circulation flows is very small and difficult to measure directly by instruments; however, in our opinion, they can significantly complicate the transverse mixing at the confluence. The proposed hypothesis is tested in computational experiments in the framework of the three-dimensional formulation for dimensions of a real water object at the mouth of the Vishera River where it meets the Kama. Calculations demonstrate that, at sufficiently large flow rates, the two waters practically do not mix in the horizontal direction throughout the depth over long distances from the confluence. It has been found that a two-vortex flow is formed downstream the confluence, which just attenuates the mixing; the fluid motion in the vortices is such that, near the free surface, the fluid moves from the banks to the middle of the riverbed