Influence of reaction heat on time dependent processes in a chemically reacting binary mixture

In this paper we study time dependent problems, like the propagation of sound waves or the behavior of small local wave disturbances induced by spontaneous internal fluctuations, in a binary mixture undergoing a chemical reaction of type A+A= B+B. The study is developed at the hydrodynamic Euler level, in a chemical regime of fast reactive process in which the chemical reaction is close to its final equilibrium state. The hydrodynamic state of the mixture is described by the balance equations for the mass densities of both constituents A and B, together with the conservation laws for the momentum and total energy of the mixture. The progress of the chemical reaction is specified by an Arrhenius-type reaction rate which defines the net balance between production and consumption of each constituent. Assuming that the considered time dependent problems induce weak macroscopic deviations, the hydrodynamic equations are linearized through a normal mode expansion of the state variables around the equilibrium state. From the dispersion relation of the normal modes, we determine the free and forced phase velocities as well as the attenuation coefficients of the waves. We show that the dispersion and absorption of these waves depend explicitly on the heat of the chemical reaction, the concentrations of the constituents and the activation energy through the exponential factor of Arrhenius law.Fundação para a Ciência e a Tecnologia, Brazilian Research Council (CNPq

Spectral distribution of scattered light from a chemical relaxation system

The aim of this work is to describe the light scattering spectra of a quaternary reacting gas mixture from the macroscopic field equations derived from the kinetic BGK-type model proposed by the authors in a previous paper. The study is developed in a hydrodynamic regime for which the system of the field equations of constituent number densities, momentum and temperature of the mixture is closed by the constitutive equations for rate of reaction, diffusion velocities, pressure tensor and heat flux vector. The spontaneous Rayleigh-Brillouin scattering is calculated from the constituent density perturbations of the linearized field equations, and its line shape is drawn for two different mixtures of the Hydrogen-Chlorine system showing the induced chemical reaction effect.Brazilian Research Council (CNPq)Universidade do Minho. Centro de Matemática(CMat)Fundação para a Ciência e a Tecnologia (FCT) - FCT-PTDC/MAT/68615/2006Italian National Project GNFM 2009/1

A kinetic model for chemical reactions without barriers : transport coefficients and eigenmodes

The kinetic model of the Boltzmann equation proposed in the work of Kremer and Soares 2009 for a binary mixture undergoing chemical reactions of symmetric type which occur without activation energy is revisited here, with the aim of investigating in detail the transport properties of the reactive mixture and the influence of the reaction process on the transport coefficients. Accordingly, the non-equilibrium solution of the Boltzmann equation is determined through an expansion in Sonine polynomials up to the first order, using the Chapman-Enskog method, in a chemical regime for which the reaction process is close to its final equilibrium state. The non-equilibrium deviations are explicitly calculated for what concerns the thermal-diffusion ratio and coefficients of shear viscosity, diffusion and thermal conductivity. The theoretical and formal analysis developed in the present paper is complemented with some numerical simulations performed for different concentrations of reactants and products of the reaction as well as for both exothermic and endothermic chemical processes. The results reveal that chemical reactions without energy barrier can induce an appreciable influence on the transport properties of the mixture. Oppositely to the case of reactions with activation energy, the coefficients of shear viscosity and thermal conductivity become larger than those of an inert mixture when the reactions are exothermic. An application of the non-barrier model and its detailed transport picture is included in this paper, in order to investigate the dynamics of the local perturbations on the constituent number densities, and velocity and temperature of the whole mixture, induced by spontaneous internal fluctuations. It is shown that for the longitudinal disturbances there exist two hydrodynamic sound modes, one purely diffusive hydrodynamic mode and one kinetic mode.This paper is partially supported by the Brazilian Research Council (CNPq), by Minho University Mathematics Centre (CMAT-FCT) and by Project FCT-PTDC/MAT/68615/2006

Recovery Program of the Historic Center of Salvador: public policy and social participation

As iniciativas de revalorização dos Centros Históricos tem se traduzido, nas últimas décadas, em projetos de intervenção subsidiados e direcionados por investimentos públicos com inserções dos agentes privados. As políticas públicas que deram suporte a essas intervenções, embora anunciassem o objetivo de preservá-los e inseri-los nos contextos urbanos, privilegiaram a atividade turística e à indústria cultural levando à "gentrification" e efeitos sobre a população e cultura locais e o patrimônio imaterial. A análise dos momentos da implantação do Programa de Recuperação do Centro Histórico de Salvador (Bahia), iniciado em 1991 permite questionar a atuação do Estado e os resultados alcançados.Las iniciativas de recuperación de los centros históricos se han expresado en las últimas décadas, en proyectos de intervención subvencionados y dirigidos por investimentos públicos con asociaciones con los agentes privados. Las políticas públicas que prestan apoyo a estas intervenciones, al mismo tiempo que anunciaron el objetivo de preservarlos y integrarlos en los contextos urbanos, favoreceran el turismo y la industria cultural, que conduce a la "gentrificación" y efectos sobre la población y cultura locales y el patrimonio inmaterial. El análisis de los tiempos de implantación del Programa de Recuperación del Centro Histórico de Salvador (Bahía), iniciado en 1991 permite cuestionar la acción del Estado y los resultados obtenidos.Initiatives upgrading of historic centers have been expressed in recent decades, in intervention projects subsidized by targeted public investments with insertions of private agents. Public policies that provide support for these interventions, while announcing the goal to preserve them and put them in urban settings, favored the tourism and cultural industries, leading to gentrification and to other negative effects on the local population and on their cultural inheritance. The analysis of the implementation times of the Program of Recuperation of the Historical Centre of Salvador (Bahia), initiated in 1991, allows us to raises questions as to the ways the public institutions acted and the results obtained in different moments of the intervention process

Contralateral force irradiation for the activation of tibialis anterior muscle in carriers of Charcot-Marie-Tooth disease: effect of PNF intervention program

OBJETIVO: Avaliar a resposta do músculo tibial anterior (TA) após um protocolo de cinco semanas com irradiação contralateral de força através de diagonais de facilitação neuromuscular proprioceptiva (FNP) em pacientes com polineuropatia desmielinizante associada à doença de Charcot-Marie-Tooth do tipo 1A (CMT-1A). MÉTODOS: Participaram deste estudo 12 pacientes, de ambos os sexos. Eles foram tratados em uma frequência de duas vezes por semana, durante cinco semanas. Em cada sessão, foram utilizadas as diagonais de Chopping, extensão-adução com rotação interna (EARI) e flexão-abdução com rotação interna (FARI). As diagonais foram repetidas quatro vezes, em ambos os membros superiores e inferiores; cada diagonal tinha duração média de 6 segundos. Durante as execuções, a resposta muscular do TA foi registrada por um eletromiógrafo de superfície, desprezando-se os 2 segundos iniciais e finais de cada diagonal. A média dos valores de Root Mean Square (RMS) das quatro repetições foi normalizada em porcentagem. Os dados iniciais e finais foram submetidos ao teste em t para amostras pareadas com valores de p significativos <0,05. RESULTADOS: A irradiação de força contralateral, através da diagonal de Chopping à direita e à esquerda, aumentou os valores de RMS em porcentagem do músculo TA na última sessão quando comparados com os valores da primeira sessão (t=-3,94) e (t=-3,87), respectivamente. Na mesma direção, a diagonal EARI aumentou os valores de RMS em porcentagem do músculo TA na última sessão quando comparados com os valores da primeira sessão (t=-3,3) e (t=-4,58), respectivamente. A única diagonal que não produziu valores maiores de irradiação de força contralateral nos músculos TA direito e esquerdo foi a diagonal FARI (t=-2,31) e (t=-1,55). CONCLUSÃO: Esses resultados podem justificar a utilização de um programa de tratamento através de diagonais de FNP em portadores de CMT-1A que possuam dificuldades na ativação do músculo TA.OBJECTIVE: To evaluate the response of the tibialis anterior (TA) muscle following a five-week protocol with contralateral irradiation force through Proprioceptive Neuromuscular Facilitation (PNF) diagonals in patients with demyelinating polyneuropathy associated with Charcot-Marie-Tooth disease type 1A (CMT-1A). METHODS: The study included 12 patients of both sexes. They were treated twice-weekly for 5 weeks. At each session, they performed the following diagonal patterns: chopping, extension-adduction with internal rotation (EAIR) and flexion-abduction with internal rotation (FAIR). The diagonals were repeated four times, in both upper and lower limbs, with each repetition lasting six seconds on average. During execution, the response of the TA muscle was recorded by a surface electromyograph disregarding the initial and final two seconds of each diagonal. The mean RMS values of the four repetitions were normalized in percentage. The initial and final data were analyzed through the t test for paired samples with significant p-values <0.05. RESULTS: The contralateral force irradiation with the chopping diagonal to the left and to the right increased the percentage RMS values of the TA muscle in the last session when compared with the values of the first session (t=-3.94 and t=-3.87, respectively). Similarly, the EAIR diagonal increased the percentage RMS values of the TA muscle in the last session when compared with the values of the first session (t=-3.3 and t=-4.58, respectively). The only diagonal that did not produce higher values of contralateral force irradiation in the TA muscle, left and right, was the FAIR (t=-2.31 and t=-1.55). CONCLUSION: These results may justify the use of a treatment program with PNF diagonals in patients with CMT-1A who have difficulty activating the TA muscle.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)edital Genética Clinic

Spinocerebellar ataxia : functional analysis of the stomatognathic system

Neurodegenerative diseases that affect the cerebellum, especially in elderly individuals, cause impairment of motor coordination and quality of life. The presente study evaluated the electromyographic activity and thickness of the right and left masseter and temporal muscles, and the maximum molar bite force of individuals with spinocerebellar ataxia. Twenty-eight individuals were divided into two groups: those with (n=14) and without (n=14) spinocerebellar ataxia. Data on the masticatory muscles obtained from the electromyographic activity (resting, right and left laterality and protrusion), muscle thickness (maximal voluntary contraction and tensile strength) and maximum bite force (right and left) were tabulated and descriptive analysis using Student?s t-test (P ? 0.05). In the comparison between groups, greater electromyographic activity was demonstrated for individuals with spinocerebellar ataxia, with a statistically significant difference in protrusion and laterality for the temporal muscles (P = 0.05). There was no statistically significant difference between the groups for masticatory muscles thickness in the conditions evaluated. For maximum molar bite force, the group with spinocerebellar ataxia showed lower bite force (P ? 0.05). The data obtained suggest that spinocerebellar ataxia promotes functional reduction in the stomatognathic system, mainly affecting the electromyographic activity and bite force, hindering chewing, with a resultant alteration of nutritional intake and a decrease of quality of life

Alterations in the stomatognathic system due to amyotrophic lateral sclerosis

Objectives: To compare the molar bite force, electromyographic activity, chewing efficiency and thickness of the masseter and temporalis muscles in individuals with amyotrophic lateral sclerosis (ALS) and healthy individuals. Material and Methods: Thirty individuals enrolled in the study were divided into the study group (with ALS, n=15) and control group (healthy individuals, n=15). Data regarding molar bite force (right and left), electromyographic activity (mandibular rest, right and left laterality, protrusion, and maximum voluntary contraction), chewing efficiency (habitual and non-habitual), and masticatory muscle thickness (rest and maximum voluntary contraction) were tabulated and subjected to statistical analysis (Student’s t-test, p≤0.05). Results: Comparisons between the groups demonstrated a statistically significant increase in the electromyographic activity of the right masseter (p=0.03) and left masseter (p=0.03) muscles during mandibular rest; left masseter (p=0.00), right temporalis (p=0.00), and left temporalis (p=0.03) muscles during protrusion; and right masseter (p=0.00), left masseter (p=0.00), and left temporalis (p=0.00) muscles during left laterality, in individuals with ALS as compared with healthy individuals. A statistically significant decrease was observed in the habitual chewing efficiency of the right masseter (p=0.00) and right temporalis (p=0.04) muscles in individuals with ALS. No statistically significant difference between the groups was found the masticatory muscle thickness and maximal molar bite force. Conclusions: ALS may lead to modifications in the activities of the stomatognathic system, including muscular hyperactivity and reduction in chewing efficiency; however, no change has been observed in the masticatory muscle thickness and molar bite force

Conservation practice at the historic garden of the modern ensemble of SUDENE: a didactic experience in the architecture and urbanism undergraduate course at Federal University of Pernambuco

The historic gardens are a living heritage and, as an ephemeral artwork​, they are linked to the plant condition and require constant care to not lose their patrimonial values, along with their authenticity, integrity and significance. Thus, the objective of this article was to synthesize the main discussions and results obtained in the discipline Workshop of Architecture, Urbanism and Landscaping 2A - Landscape Architecture of the undergraduate degree in Architecture and Urbanism at the Federal University of Pernambuco, a pioneering experience directed to the understanding and conservation of historic gardens, a theme that still has been little explored in the undergraduate courses of architecture and urbanism in Brazil. The Garden of the Superintendence for Development of the Northeastern Region – Sudene, designed by Roberto Burle Marx in 1972, it was chosen as an object of study for being part of a modern ensemble formed by a group of buildings and a garden and for being a landmark of modernism in Brazil, which, due to a series of issues, faces a broad process of decharacterization. At the end of the workshop, a preliminary study had been drawn up, with a set of guidelines, which will support a restoration project for the garden.Os jardins históricos são um patrimônio vivo e, como obra de arte efêmera, condição atrelada ao vegetal, necessitam de cuidados constantes para que seus valores patrimoniais não sejam perdidos e, consequentemente, a autenticidade, a integridade e a significância. Desta forma, objetivou-se com este artigo, sintetizar as principais discussões e resultados obtidos na disciplina Oficina de Arquitetura, Urbanismo e Paisagismo 2A – Arquitetura da Paisagem do Curso de Arquitetura e Urbanismo da Universidade Federal de Pernambuco pelo pioneirismo em ofertar uma disciplina direcionada ao entendimento e à conservação de jardins históricos, tema ainda pouco explorado no âmbito da graduação dos cursos de arquitetura e urbanismo no Brasil. O Jardim da Superintendência do Desenvolvimento do Nordeste, projetado em 1972 por Roberto Burle Marx, foi escolhido como objeto de estudo por ser um marco do modernismo no Brasil (jardim e edifício), bem como por estar em processo de descaracterização. Ao final da oficina chegou-se a um estudo preliminar com diretrizes que embasarão o projeto de restauro do jardim

The Casa Forte Square: a historic garden, a cultural heritage of Brazil

O jardim moderno brasileiro foi criado em Recife por Roberto Burle Marx na década de 1930. Ele concebia o jardim como uma reintegração estética dos elementos da natureza onde a vegetação era elemento principal. Com essa intenção, projetou treze jardins públicos entre 1935 e 1937, incluindo a Praça de Casa Forte, seu primeiro projeto. Sendo o jardim perecível e renovável, segundo a Carta de Florença, por toda dinâmica física e biológica, a falta de conservação provoca sua degradação. Assim sendo, apresenta-se neste artigo a historiografia da Praça de Casa Forte, de forma a subsidiar ações efetivas de conservação.Roberto Burle Marx created the Brazilian modern garden in Recife in the 1930s. He conceived the garden as an esthetic reintegration of the components of nature in which vegetation was the main element and, considering that, designed thirteen public gardens from 1935 to 1937, including Casa Forte Square, his first garden design. As the garden is perishable and renewable, according to The Florence Charter, due to all the physical and biological dynamics, the lack of conservation causes its degradation. Thus, this article presents the historiography of Casa Forte square to subsidize effective conservation actions

Plano paisagístico de Burle Marx para o campus Joaquim Amazonas, Universidade Federal de Pernambuco, Brasil

Throughout his career, Burle Marx constantly demonstrated his concern for nature conservation, expressing the use of native species as one of the design principles of his gardens, of various types. Despite this, there is little discussion of his plans for college campuses. With the aim of analyzing the design principles of the landscape designer in the landscaping plan for the Joaquim Amazonas—UFPE campus, this study uses physical and digital documentary sources to understand the principles adopted, comparing them with his speeches and similar projects, contributing to the historical study of modern landscaping and providing a basis for future research on his works.A lo largo de su carrera, Burle Marx demostró constantemente su preocupación por la conservación de la naturaleza, expresando el uso de especies nativas como uno de los principios de diseño de sus jardines, de diversa índole. A pesar de esto, hay poca discusión sobre sus planes para los campus universitarios. Con el objetivo de analizar los principios de diseño del paisajista en el plan de paisajismo del campus Joaquim Amazonas—UFPE, este estudio utiliza fuentes documentales físicas y digitales para comprender los principios adoptados, comparándolos con sus discursos y proyectos similares, contribuyendo al estudio histórico del paisajismo moderno y proporcionando una base para futuras investigaciones sobre sus obras.Burle Marx demonstrou constantemente em sua carreira, preocupação com a conservação da natureza, expressando o uso de espécies nativas como um dos princípios projetuais de seus jardins, de variadas tipologias. Apesar disso, há pouca discussão sobre seus planos para campi universitários. Com objetivo de analisar os princípios projetuais do paisagista no plano paisagístico para o campus Joaquim Amazonas—UFPE, esse estudo utiliza fontes documentais físicas e digitais para compreender os princípios adotados, comparando-os com seus discursos e projetos similares, contribuindo para o estudo histórico do paisagismo moderno e fornecendo base para futuras pesquisas sobre suas obras