O eletrólito suporte e suas múltiplas funções em processos de eletrodo

The aim of this work is to present the principal properties and applications of supporting electrolytes (SE) to students, teachers and researchers interested in electrode processes. Different aspects are discussed including the importance of SE in maintaining constant the activity coefficients and the diffusion coefficients and reducing the transport number of electroactive species. Its effect on the electrochemical kinetic parameters is also presented.

Lap number properties for p-Laplacian problems investigated by Lyapunov methods

In this work we consider a one-dimensional quasilinear parabolic equation and we prove that the lap number of any solution cannot increase through orbits as the time passes if the initial data is a continuous function. We deal with the lap number functional as a Lyapunov function, and apply lap number properties to reach an understanding on the asymptotic behavior of a particular problem. (c) 2006 Published by Elsevier Ltd.

Variable structure control of switched systems based on Lyapunov-Metzler-SPR systems

This paper presents two Variable Structure Controllers (VSC) for continuous-time switched plants. It is assumed that the state vector is available for feedback. The proposed control system provides a switching rule and also the variable structure control input. The design is based on Lyapunov-Metzler (LM) inequalities and also on Strictly Positive Real (SPR) systems stability results. The definition of Lyapunov-Metzler-SPR (LMS) systems and its direct application in the design of VSC for switched systems are introduced in this paper. Two examples illustrate the design of the proposed VSC, considering a plant given by a switched system with a switched-state control law and two linear time-invariant systems, that are not controllable and also can not be stabilized with state feedback. ©2008 IEEE.

Improving the stability conditions of TS fuzzy systems with fuzzy Lyapunov functions

In this paper, the fuzzy Lyapunov function approach is considered for stabilizing continuous-time Takagi-Sugeno fuzzy systems. Previous linear matrix inequality (LMI) stability conditions are relaxed by exploring further the properties of the time derivatives of premise membership functions and by introducing a slack LMI variable into the problem formulation. The stability results are thus used in the state feedback design which is also solved in terms of LMIs. Numerical examples illustrate the efficiency of the new stabilizing conditions presented. © 2011 IFAC.

Apatia, funções cognitivas e funcionalidade motora em idosos com doença de Alzheimer

The aims of this study were to characterize the presence of apathy in patients with AD, determine the relationship between apathy, motor function and cognitive function, and to verify differences among patients stratified by level of apathy in relation to cognitive and motor abilities. Methods: A cross-sectional study was conducted of 37 patients with AD. The following tests were used: MoCA, the Frontal Assessment Battery, Verbal Fluency, Clock Drawing Test, Andreotti & Okuma Battery Tests, Sit and Reach, Resistance of Upper Limbs - AAHPERD Battery Test, Sit and Lift Chair and the Apathy domain of the Neuropsychiatric Inventory. After verifying the normality of the data distribution, comparisons were made using Student's t-test and the U Mann Whitney test; relationships were also assessed using Pearson's and Spearman's correlation coefficients. All analyses were considered to be statistically significant at a p-value of 0.05. Results: 46% of participants in this study showed mild symptoms of apathy. Significant and weak associations were found (p=0.04) between apathy and the attention domain on the MoCA and between apathy and the Walk Test. Analysis of differences in cognitive and motor functions according to participants' level of apathy revealed no significant differences for any of the variables. Conclusion: Apathy was reflected in attention and the Walk Test, suggesting these variables may be related to cognitive and functional decline in AD patients.

Efeitos do treinamento com pesos nas funções cognitivas de idosos com doença de Alzheimer

Deterioration in cognitive functions is characteristic in Alzheimer's disease (AD) and may be associated with decline in daily living activities with consequent reduced quality of life. Objective: To analyze weight training effects on cognitive functions in elderly with AD. Subjects: 34 elderly with AD were allocated into two groups: Training Group (TG) and Social Gathering Group (SGG). Methods: Global cognitive status was determined using the Mini-Mental State Exam. Specific cognitive functions were measured using the Brief Cognitive Battery, Clock Drawing Test and Verbal Fluency Test. The protocols were performed three times a week, one hour per session. The weight training protocol consisted of three sets of 20 repetitions, with two minutes of rest between sets and exercises. The activities proposed for the SGG were not systematized and aimed at promoting social interaction among patients. The statistical analyses were performed with the U Mann Whitney and Wilcoxon tests for group comparisons. All analyses were considered statistically significant at a p-value of 0.05. Results: There were no significant differences associated to the effects of the practice of weight training on cognition in AD patients. Conclusion: In this study, no improvement in cognitive functions was evident in elderly with AD who followed a low intensity resistance exercise protocol. Thus, future studies could evaluate the effect of more intense exercise programs.

Reducing the conservatism of LMI-based stabilisation conditions for TS fuzzy systems using fuzzy Lyapunov functions

In this article, the fuzzy Lyapunov function approach is considered for stabilising continuous-time Takagi-Sugeno fuzzy systems. Previous linear matrix inequality (LMI) stability conditions are relaxed by exploring further the properties of the time derivatives of premise membership functions and by introducing slack LMI variables into the problem formulation. The relaxation conditions given can also be used with a class of fuzzy Lyapunov functions which also depends on the membership function first-order time-derivative. The stability results are thus extended to systems with large number of rules under membership function order relations and used to design parallel-distributed compensation (PDC) fuzzy controllers which are also solved in terms of LMIs. Numerical examples illustrate the efficiency of the new stabilising conditions presented. © 2013 Copyright Taylor and Francis Group, LLC.

Problemas de valor de contorno não clássicos: uma abordagem usando funções de Green

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Funções textual-interativas dos marcadores discursivos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Percepção de tempo e outras funções cognitivas, funcionalidade motora e o nível de atividade física de idosos com Doença de Alzheimer no estágio leve

Pós-graduação em Ciências da Motricidade - IBRC

Controle robusto com realimentação derivativa de sistemas não lineares via LMI

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Otimização de controladores robustos de sistemas dinâmicos sujeitos a falhas estruturais

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Identificação de funções de transferência utilizando como entrada um degrau

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência do exercício físico em memória e funções executivas de pessoas com doença de Parkinson

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito do treinamento com pesos na apatia, funções cognitivas frontais e funcionalidade motora em pacientes com doença de Alzheimer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)