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Transportation Telematics Systems Operation Efficiency Modeling
No full textabstractEN: In the paper is presented a method of assessing of the exploitation efficiency of transport telematics systems. In order to obtain as an overall assessment of transport telematics systems, as the method for evaluating was accepted the multi-state analysis of the exploitation process. Then was elaborated the model of exploitation process of the telematics system. The problem of fundamental importance in the study of efficiency is to determine the partial measures of effectiveness. Using the characteristics of the exploitation process, a model of exploitation efficiency of telematics system was elaborated and the measures of its evaluation are presented.score: 5collation: 99-11
Functional and Operational Structures of the Motorway Telematics System
No full textabstractEN: The paper presents the issues relating to the identification of functional and operational structures of the motorway telematics system. General functional structure of the motorway telematics system has been presented, as well as its components used for transmission, transfer and reception of information. Then, the information flow process has been shown for a selected group of telematics services during the tolling process.score: 5collation: 223-23
Design of the Electronic Protection Systems with Utilization of the Method of Analysis of Reliebility Structures
No full textabstractEN: Paper presents process of design of the electronic protection systems with utilization of the method of analysis of reliability structures. Utilization of the method of analysis of reliability structures makes possible the enlargement of the values of the reliability coefficients of the designed systems by accomplishment of the analyses and simulations which allow to select of the optimal system structure with regard to the user requirements as well as the characteristics of the protected object (e.g. location of the protected objects in terrain, distances between buildings).score: 3collation: 421-42
Variational optimization of power yield in industrial systems
No full textabstractEN: Variational optimization is applied to simulation and modeling of dynamical energy converters, in particular thermal and solar engines. Basic thermodynamic principles lead to expressions for converter)s efficiency and limiting work. Work generated is a cumulative effect obtained in a system of a resource fluid, engines, and an infinite bath. The limiting work function depends on thermal coordinates and a dissipation index, h, in fact the Hamiltonian of the optimization problem of minimum entropy production. Bounds on work delivery implied by the limiting function are stronger than those predicted by the reversible work potential.score: 7collation: 1017-102
Reversed phase composite polymeric electrolytes based on poly(oxyethylene)
No full textabstractEN: In this paper, a concept and structural characterization of novel class of composite polymeric electrolytes is systematically presented. These are polymer-in-ceramic composites consisting of porous alumina matrices, distinguished by different pore architectures (anodized alumina with narrow and well-ordered parallel pores as well as random structures obtained by various methods from alumina grains by sintering); and a complex of lithium tetraoxochlorate and poly(oxyethylene) of different molecular weight. These new electrolytes exhibit room temperature conductivities exceeding 10?3 S·cm?1, low resistance of the interface with lithium electrode, excellent thermal and electrochemical stability. We show combined structural (environmental XRD), thermal and conductivity studies on composite electrolyte systems that were never published before and provide a new explanation of the enhancement of conductivity at subambient temperatures. Feasibility of cells employing electrodes prepared directly on the electrolyte support with a novel synthesis method (MPCVD) is also emphasized.score: 45collation: 1785-179
Hamilton-Jacobi-Bellman framework for optimal control in multistage energy systems
No full textabstractEN: We enunciate parallelism for structures of variational principles in mechanics and thermodynamics in terms of the duality for thermoeconomic problems of maximizing of production profit and net profit which can be transferred to duality for least action and least abbreviated action which appear in mechanics. With the parallelism in mind, we review theory and macroscopic applications of a recently developed discrete formalism of Hamilton–Jacobi type which arises when Bellman's method of dynamic programming is applied to optimize active (work producing) and inactive (entropy generating) multistage energy systems with free intervals of an independent variable. Our original contribution develops a generalized theory for discrete processes in which these intervals can reside in the model inhomogeneously and can be constrained. We consider applications to multistage thermal machines, controlled unit operations, spontaneous relaxations, nonlinear heat conduction, and self-propagating reaction–diffusion fronts. They all satisfy a basic functional equation that leads to the Hamilton–Jacobi–Bellman equation (HJB equation) and a related discrete optimization algorithm with a maximum principle for a Hamiltonian. Correspondence is shown with the well-known HJB theory for continuous processes when the number of stages approaches an infinity. We show that a common unifying criterion, which is the criterion of a minimum generated entropy, can be proven to act locally in the majority of considered cases, although the related global statements can be invalid far from equilibrium. General limits are found which bound the consumption of the classical work potential (exergy) for finite durations.score: 50collation: 165-25
Stability and Stabilization of Thermally Induced Vibrations of Cylindrical Shells
No full textabstractEN: A review of the analytical research of smart composite structures that have a relevance to buckling, vibrations, parametric vibrations, and dynamic stability of oneand two-dimensional mechanical systems applied in mechanical and civil engineering is presented. Special attention is paid to the dynamic behavior of circular cylindrical shells due to nonuniform time-dependent temperature fields. The shell is heated, and it is assumed that a time- and space-dependent temperature field is known. To stabilize thermally induced transverse vibrations the host structure is integrated with a control system consisting of piezoelectric sensors and actuators. Distributed piezoelectric elements are implemented to suppress the motion caused by thermal disturbances. Two particular problems are analyzed in detail. The first is devoted to the stability analysis of a closed cylindrical shell subjected to a time-dependent temperature field. The stabilization is obtained by applying the velocity feedback and electroded piezoelectric sensors/actuators with a suitable polarization profile. In the second problem the technique of the dynamic stability analysis is extended to the thermally activated shape memory alloy hybrid rotating cylindrical shell.score: 20collation: 605-62
Liapunov functionals application to dynamic stability analysis of continuous systems
No full textabstractEN: Using the appropriate energy-like Liapunov functional sufficient conditions for the uniform stability of undeflected form of structures are derived. The structures are described by partial differential equations and integro-partial differential equations with time and space–time-dependent coefficients. Stability domains obtained by applying the linearized equations of motion are compared with those employing the typical nonlinearity e.g. Kármán nonlinear effects and Brazier's nonlinearity. A relation between the stability of nonlinear equations and linearized ones is analyzed. An influence of geometrical, and material parameters as well as constant components of axial and in-plane forces for different classes of parametric excitation on stability regions is shown.score: 40collation: e169-e18
Dynamic Stability of Rotating Composite Shells with Thermoacttve Shape Memory Alloy Fibers
No full textabstractEN: In this article the technique of the dynamic stability analysis proposed for the conventional laminated shells is extended to the activated shape memory alloy hybrid cylindrical shells. The thin symmetrically balanced laminated shell contains both the conventional (e.g., graphite or glass) fibers oriented at +ϑ and − ϑ to the shell axis and the activated shape memory alloy fibers axially oriented. Rotary and coupling inertias are neglected. The rotating with a constant angular velocity shell is simply supported at the edge hoops. The effect of returning to the original geometry after a large inelastic deformation is called the shape memory effect. Changing the temperature of the layer we modify the basic mechanical properties such as Young's modulus and the damping coefficient. The purpose of this article is to solve the dynamic stability problem and to answer the question, how does the temperature activation change dynamic stability domains of the shell. Using the standard stability technique leads to the effective sufficient criterion of the dynamic stability. The stability regions as Junctions of angular velocity, the damping coefficient, and properties of shell material are given. The results indicate that the global activation increases the admissible angular velocity both for the glass-epoxy /NiTi-epoxy and graphite-epoxy /NiTi-epoxy hybrid shellsscore: 20collation: 327-33