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Modelling and Fault Diagnosis Approach for PEMF...
74,00 € *
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Proton exchange membrane fuel cell (PEMFC), as a source of electrical power, provides numerous benefits such as zero carbon emission and high reliability as compared to wind and solar energy. The first part of this book attempt to model the voltage of PEMFC using simple and effective semi-empirical equations. The initial feature of the proposed technique is to incorporate the features of the mechanistic model with less complex equations. The second part of the book focuses on modelling the PEMFC temperature. The fault diagnosis procedure has also been elaborated for flooding and drying faults of PEMFC. Moreover, the electrical equivalent modelling has also been discussed all of the above-mentioned models consider ambient conditions changes directly.

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Stand: 27.02.2020
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Spectral Methods
104,99 € *
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Spectral methods, particularly in their multidomain version, have become firmly established as a mainstream tool for scientific and engineering computation. While retaining the tight integration between the theoretical and practical aspects of spectral methods that was the hallmark of their 1988 book, Canuto et al. now incorporate the many improvements in the algorithms and the theory of spectral methods that have been made since then. This second new treatment, Evolution to Complex Geometries and Applications to Fluid Dynamics, provides an extensive overview of the essential algorithmic and theoretical aspects of spectral methods for complex geometries, in addition to detailed discussions of spectral algorithms for fluid dynamics in simple and complex geometries. Modern strategies for constructing spectral approximations in complex domains, such as spectral elements, mortar elements, and discontinuous Galerkin methods, as well as patching collocation, are introduced, analyzed, and demonstrated by means of numerous numerical examples. Representative simulations from continuum mechanics are also shown. Efficient domain decomposition preconditioners (of both Schwarz and Schur type) that are amenable to parallel implementation are surveyed. The discussion of spectral algorithms for fluid dynamics in single domains focuses on proven algorithms for the boundary-layer equations, linear and nonlinear stability analyses, incompressible Navier-Stokes problems, and both inviscid and viscous compressible flows. An overview of the modern approach to computing incompressible flows in general geometries using high-order, spectral discretizations is also provided. The recent companion book Fundamentals in Single Domains discusses the fundamentals of the approximation of solutions to ordinary and partial differential equations on single domains by expansions in smooth, global basis functions. The essential concepts and formulas from this book are included in the current text for the reader s convenience.

Anbieter: buecher
Stand: 27.02.2020
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Spectral Methods
104,99 € *
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Spectral methods, particularly in their multidomain version, have become firmly established as a mainstream tool for scientific and engineering computation. While retaining the tight integration between the theoretical and practical aspects of spectral methods that was the hallmark of their 1988 book, Canuto et al. now incorporate the many improvements in the algorithms and the theory of spectral methods that have been made since then. This second new treatment, Evolution to Complex Geometries and Applications to Fluid Dynamics, provides an extensive overview of the essential algorithmic and theoretical aspects of spectral methods for complex geometries, in addition to detailed discussions of spectral algorithms for fluid dynamics in simple and complex geometries. Modern strategies for constructing spectral approximations in complex domains, such as spectral elements, mortar elements, and discontinuous Galerkin methods, as well as patching collocation, are introduced, analyzed, and demonstrated by means of numerous numerical examples. Representative simulations from continuum mechanics are also shown. Efficient domain decomposition preconditioners (of both Schwarz and Schur type) that are amenable to parallel implementation are surveyed. The discussion of spectral algorithms for fluid dynamics in single domains focuses on proven algorithms for the boundary-layer equations, linear and nonlinear stability analyses, incompressible Navier-Stokes problems, and both inviscid and viscous compressible flows. An overview of the modern approach to computing incompressible flows in general geometries using high-order, spectral discretizations is also provided. The recent companion book Fundamentals in Single Domains discusses the fundamentals of the approximation of solutions to ordinary and partial differential equations on single domains by expansions in smooth, global basis functions. The essential concepts and formulas from this book are included in the current text for the reader s convenience.

Anbieter: buecher
Stand: 27.02.2020
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Some Studies on First Order Matrix Difference E...
76,90 € *
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Here, we prove necessary and sufficient conditions for the existence of at least one psi-bounded solution of the matrix difference equation, under the assumption that the non-homogeneous function is a psi-summable matrix function and psi-bounded matrix function on Z+, and also obtain results relating to the asymptotic behavior of the psi-bounded solutions of this equation on Z+. Further, we obtain sufficient conditions for the existence and uniqueness of psi-bounded solutions for the nonlinear vector and matrix difference equation on Z.The concepts of psi- (uniform) stability and psi-asymptotic stability for non linear vector and matrix difference equations are introduced and also obtain sufficient conditions for the psi-(uniform)stability & psi-asymptotic stability of trivial solution of nonlinear vector and matrix difference equation. Also here, we provide a way to incorporate difference equations with fuzzy sets to form a new fuzzy logic system called fuzzy difference control system which can be regarded as a new approach to intelligent control and also obtain sufficient conditions for the controllability & observability of the fuzzy vector and matrix difference control systems.

Anbieter: Dodax
Stand: 27.02.2020
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Symbolic Modeling and Optimization of Elastic M...
45,80 € *
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The method of elastic multibody systems is a powerful tool to simulate and analyze mechanical systems. Its main applications are systems with large, nonlinear motions but small deformations. Here, the software Neweul-M2 is described, which is a simulation package in Matlab. The author of this thesis was involved in its development. It uses the Matlab Symbolic Math Toolbox to perform symbolic computations in order to set up the kinematics and equations of motion of the system under consideration. With this approach, the symbolic engine and the large numerical toolset of Matlab can be applied. The symbolic equations of motion enable an efficient optimization of the system.In the first part, the fundamental relations to describe multibody systems and to set up the equations are explained. Here, four formulations are presented as they are implemented in Neweul-M2. Two of which result in symbolic equations, while the other two result in numerical algorithms. The different formulations are investigated by their performance on three systems.All these algorithms use only very few algebraic constraint equations. Usually, their information is contained inherently in the equations of motion. However, for some systems, e.g. when using kinematic loops, algebraic constraints are preferred. The easiest way to handle such systems is to choose an appropriate integrator which ensures that the constraint equations are respected. In these formulations, most often only the time derivatives of the constraints are considered, which can lead to integration errors. Alternatives are methods, where the generalized coordinates are projected onto the available directions of motion. Then, this combination locally respects the constraint equations, making a root-search unnecessary. Commonly, the user has to select the set of independent coordinates, when this method is applied. While this may work well for some systems, this often leads to problems in certain system configurations. Here, two alternatives are presented, which automatically select the best linear combination of generalized coordinates using the QR- or SVD-decomposition.The software Neweul-M2 is characterized by its symbolic approach and its data management. It uses a global data structure to store all information, like the system definition and the results. This data structure is freely accessible for the user. This concept makes the handling very easy for the users, as the complete information is available in readable form. Also an export to other languages can be easily done.One of the goals of implementing Neweul-M2 is to use it to optimize the elastic multibody systems under consideration. As a wide variety of different optimizations is possible with Neweul-M2 and many of them are implemented ready to use, these possibilities are explained. First, available criterion functions are presented. Among standard methods, a new method is presented which introduces additional bodies to modify the system behavior. This can be considered a shape optimization which avoids the remodelling of an elastic body in every step. The presented methods are investigated and compared using four examples.Most of the presented methods to optimize a system are implemented ready to use in Neweul-M2. With this, the user of the software has many valuable tools available to investigate and optimize a multibody system. This includes effcient implementations for a variety of systems. The software can include elastic bodies, constraint equations, arbitrary force laws, and many other useful elements. Many different possibilities are not only available concerning the optimization, but also the investigation, analysis, simulation, and visualization of systems. It can easily be extended by the user and further developers to incorporate some of the not yet investigated fields. With this, a useful toolkit has been set up, ready for many applications.

Anbieter: Dodax
Stand: 27.02.2020
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Dynamic Analysis of Mechanical Systems with Imp...
79,00 € *
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The goal of this book is to present general methodologies for dynamic analysis of mechanical systems with imperfect, that is, considering joint clearances and their tribological characteristics and surface compliance properties. Two and three- dimensional comprehensive methodologies for imperfect kinematic joints with and without lubrication are proposed. In the sequel of this process, different contact-impact force models are revisited in face of their suitability to represent collision between the bodies connected by imperfect joints. The incorporation of friction forces, based on the Coulomb friction law, is also discussed. Moreover, a general methodology, which accounts for squeeze-film and wedge-film actions, including the cavitation effect, for modeling dynamically loaded journal bearings is also presented. The equations that govern the dynamical behavior of the general mechanical systems incorporate the contact-impact forces due to the collision between the bodies that constitute the imperfect joints, as well as the hydrodynamic forces owing to the lubrication effect.

Anbieter: Dodax
Stand: 27.02.2020
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Mathematical Modelling and Fisheries Management
59,00 € *
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In ecology, we are faced with modelling complex systems involving many variables corresponding to interacting populations structured in different compartmental classes, ages and spatial patches. Models that incorporate such a variety of aspects would lead to systems of equations with many variables and parameters. Mathematical analysis of these models would, in general, be impossible. In many real cases, the dynamics of the system corresponds to two or more time scales. For example, individual decisions can be rapid in comparison to growth of the populations. In that case, it is possible to perform aggregation methods that allow one to build a reduced model that governs the dynamics of a lower dimensional system, at a slow time scale. In this book, we present a review of aggregation methods for time continuous models. We also present applications in population dynamics.

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Stand: 27.02.2020
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Minimizers for a One-Dimensional Elasticity Pro...
49,00 € *
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We study a class of problems in forced phase transitions in one-dimensional, shape-memory solids. The problems incorporate a prescribed body force B which delivers live loading and a non- convex stored energy function of the strain W. The continuity and differentiability requirements over W and B are standard. Assuming that B is concave and under mild growth conditions on W and B, we obtained existence of minimizers for the functional in the problems posed. Then we showed that the minimizers satisfy the Euler-Lagrange equations of equilibrium almost everywhere.

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Stand: 27.02.2020
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Uncertainty in Optimization of Multi-Reservoir ...
59,00 € *
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The main objective of reservoir operation planning is to determine the amount of water released from a reservoir and the amount of energy traded in each time step to make the best use of available resources. This is done by evaluating the trade-off between the immediate and the future profit of power generation while meeting a set of constraints such as the continuity equations, transmission limits, generation and reservoir limits, flood control limits and load resource balance. Another important issue in these problems is uncertainty coming from spatial and temporal variability, inherent nature of a problem or parameter, errors in measurement due to human or technology inaccuracy and modeling errors. This research implements a Reinforcement Learning (RL) optimization algorithm to incorporate flood control constraints of the Columbia River Treaty. It considers the main sources of uncertainty in operating a large scale hydropower system: market prices and inflows by using a number of scenarios of historical data on inflow and energy prices in the learning process. The RL method reduces the time and computational effort needed to solve the operational planning problem.

Anbieter: Dodax
Stand: 27.02.2020
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