Differential Algebraic Equations
Mostrando 1-12 de 47 artigos, teses e dissertações.
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1. Two-dimensional beams in rectangular coordinates using the radial point interpolation method
Abstract The three-dimensional Theory of Elasticity equations lead to a complex solution for most problems in engineering. Therefore, the solutions are typically developed for reduced systems, usually symmetrical or two-dimensional. In this context, computational resources allow the reduction of these simplifications. The most recognized methods of algebraic
REM, Int. Eng. J.. Publicado em: 2020-03
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2. A METHODOLOGY TO OBTAIN ANALYTICAL MODELS THAT REDUCE THE COMPUTATIONAL COMPLEXITY FACED IN REAL TIME IMPLEMENTATION OF NMPC CONTROLLERS
Abstract Model Predictive Control, MPC and NMPC, and real-time optimization, RTO and D-RTO, are known to help plant operability through the mitigation of impacts caused by external disturbances. However, the usage of these tools in industry requires overcoming some challenges, for instance: accurate models of the process, particularly in regard to nonlineari
Braz. J. Chem. Eng.. Publicado em: 09/12/2019
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3. Computational algorithm for stability analysis of distribution networks with distributed generation
Abstract With the insertion of distributed generation in distribution networks, security analysis becomes crucial, in islanded operation or when the system is connected to the grid. Dynamic stability analyses are necessary in order to achieve minimum levels of security and reliability. Such analyses are obtained through the solution of the algebraic-differen
Braz. arch. biol. technol.. Publicado em: 25/11/2019
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4. Comparison and Combination of Techniques for Determining the Parameters of a Magnetic Hysteresis Model
Abstract The Jiles-Atherton scalar hysteresis model presents five parameters used to represent the material tested and used to calculate the magnetic losses. This article presents a comparative analysis of the performance of two methods of identifying these parameters. In the first method, the equations of Jiles-Atherton were assembled into a single non-line
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 12/09/2019
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5. Discharge of Non-Reactive Fluids from Vessels
Abstract This paper presents simulations of discharges from pressure vessels that consistently account for non-ideal fluid behavior in all the required thermodynamic properties and individually considers all the chemical components present. The underlying assumption is that phase equilibrium occurs instantaneously inside the vessel and, thus, the dynamics of
Braz. J. Chem. Eng.. Publicado em: 2017-10
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6. Free Vibration Analysis of Reinforced Composite Functionally Graded Plates with Steady State Thermal Conditions
Abstract The present paper deals with free vibration of functionally graded fiber reinforced rectangular plates subjected to thermal loads. The rectangular plates are assumed orthotropic. The continuous grading fiber reinforced plates have a smooth variation in matrix volume fraction in the thickness direction. Two different types of volume fraction profiles
Lat. Am. j. solids struct.. Publicado em: 2017-06
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7. STEADY STATE AND PSEUDO-TRANSIENT ELECTRIC POTENTIAL USING THE POISSONBOLTZMANN EQUATION
A method for analysis of the electric potential profile in saline solutions was developed for systems with one or two infinite flat plates. A modified Poisson-Boltzmann equation, taking into account nonelectrostatic interactions between ions and surfaces, was used. To solve the stated problem in the steady-state approach the finite-difference method was used
Braz. J. Chem. Eng.. Publicado em: 2015-03
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8. Dynamic Analysis and critical speed of rotating laminated conical shells with orthogonal stiffeners using generalized differential quadrature method
This paper presents effects of boundary conditions and axial loading on frequency characteristics of rotating laminated conical shells with meridional and circumferential stiffeners, i.e., stringers and rings, using Generalized Differential Quadrature Method (GDQM). Hamilton's principle is applied when the stiffeners are treated as discrete elements. The con
Lat. Am. j. solids struct.. Publicado em: 2013-03
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9. Numerical Studies on Flow Behavior of Composite Propellant Slurry During Vacuum Casting
Abstract: Rockets are powered by composite solid propellant, which is a heterogeneous system consisting of solid oxidizer and metallic fuel dispersed in a polymeric fuel binder matrix. The slurry casting technique under vacuum/gravity condition is well-established for performing a different class of large sized case bonded rocket motors. During propellant ca
J. Aerosp. Technol. Manag.. Publicado em: 2012-06
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10. Integração numérica de sistemas não lineares semi-implícitos via teoria de controle geométrico / Numerical integration of non-linear semi-implicit square systems via geometric control theory.
This work improves a method to approximate solutions for a class of differential algebraic equations (DAEs), known as systems semi-implicit square. The method, called here MII, is based on geometric theory of decoupling for nonlinear systems combined with efficient techniques numerical analysis. It uses an algorithum that mixes symbolic and numerical calcula
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 04/11/2011
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11. Mathematical modeling of emulsion copolymerization process of butyl acrylate and vynil acetate. / Modelagem matemática do processo de copolimerização em emulsão de acrilato de butila e acetato de vinila.
Polimeric materials have been largely used and, today, more stringent specifications have been imposed to these materials for special applications. In general, microstructure exercises intense influence on the macroscopic properties of the polymer: therefore, the control of the microstructure and its relation with these properties is of strategic interest. M
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 05/04/2011
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12. Dynamic optimization of a FCC converter unit: numerical analysis
Fluidized-bed Catalytic Cracking (FCC) is a process subject to frequent variations in the operating conditions (including feed quality and feed rate). The production objectives usually are the maximization of LPG and gasoline production. This fact makes the FCC converter unit an excellent opportunity for real-time optimization. The present work aims to apply
Brazilian Journal of Chemical Engineering. Publicado em: 2011-03