Acid dyes degradation by advanced oxidation processes using a low-speed rotating disk reactor

Three technologies were tested (TiO2/UV, H2O2/UV, and TiO2/H2O2/UV) for the degradation and color removal of a 25 mg L-1 mixture of three acid dyes: Blue 9, Red 18, and Yellow 23. A low speed rotating disc reactor (20 rpm) and a H2O2 concentration of 2.5 mmol L-1 were used. The dyes did not significantly undergo photolysis, although they were all degraded by the studied advanced oxidation processes. With the TiO2/H2O2/UV process, a strong synergism was observed (color removal reached 100%). Pseudo first order kinetic constants were estimated for all processes, as well as the respective apparent photonic efficiencies

Recovery of mineral dust in composite materials

This work evaluates the potential of use of mineral dust waste from stone extraction and processing industries to develop composite materials to construction sector. Actually, a high volume of mineral waste was generated, in a stone extraction and processing industries, without any type of recycling and recovery. In this work, this waste was combined with a biopolymeric material, with different mass ratios, namely 70:30 and 50:50 of mineral waste and polymeric material. To accelerate the curing process, a compression moulding process was used. After that, a several characterization tests were performed, in order to compare the main properties of the composite materials obtained with different mass ratios of mineral dust and polymeric material. The physical and mechanical tests were performed to evaluate the density, moisture absorption, flexural strength and flexural modulus. Besides that, the thermal properties were obtained using an Alambeta testing device. The experimental results show a decrease of density of the composite materials from 2.7 g cm-3 to 2.03 g cm-3, compared with virgin slate rock. In terms of mechanical performance, an increase of flexural strength from 17.1 MPa to approximately 80 MPa was verified between Viroc and the composite materials obtained. In addition to this, an HB rating on flammability test guarantees to the composite materials an excellent capacity to fire resistance. These results allow to conclude that the recycling and recovery the slate waste has a big potential of application in several areas, such as construction one.project “Fibrenamics Green -Platform for the development of innovative waste -based products”, code NORTE-01-0246-FEDER-000008, which is co-financed by the European Union, through the European Regional Development Fund (ERDF) under the NORTE 2020 -North Portugal Regional Operational Program 2014 –2020info:eu-repo/semantics/publishedVersio

Absorption effects on plasmon polariton-gap solitons in Kerr/metamaterial superlattices

ABSTRACT: A thorough study of the absorption effects on the plasmon polariton-gap solitoninduced transparency in 1D Kerr/metamaterial superlattices is presented. Results indicate that for frequencies close to the bottom or top edge of the bulk-like longitudinal plasmon-polariton gap, the transmission of a finite Kerr/metamaterial superlattice presents a multistable behavior, switching from very low values to the maximum transparency at particular values of the incident power even in the presence of loss effects. Moreover, calculations suggest the existence of resonant plasmon polariton-gap solitons of various orders depending on the particular value of the incident power. The present results reveal that plasmon polariton-gap soliton-induced resonant solutions lead to the transparency of a stack with nonlinear inclusions, a nonlinear optical analog of the electronic barrier-transmission resonances

AUTOAVALIAÇÃO INSTITUCIONAL: UMA ABORDAGEM POR PROCESSOS E PROJETOS

Este artigo refere-se ao processo de Autoavaliação Institucional realizado em um dos Institutos Federais de Educação Profissional e Tecnológica do Brasil, o Instituto Federal Fluminense. O processo é baseado nos princípios do INEP (Instituto Nacional de Estudos e Pesquisas Educacionais Anísio Teixeira), mas é considerado inovador na sua forma de concepção, pois utiliza de conceitos e práticas relacionados a modelagem de processo e gerência de projetos. A modelagem dos processos da Autoavaliação Institucional ocorreu através do desenho das suas etapas e a estruturação de cada autoavaliação ocorreu na forma de projeto. Para este artigo foi utilizada a autoavaliação dos cursos ofertados regularmente pelo instituto. Como resultado deste trabalho propõe-se a melhoria dos processos organizacionais do instituto baseada nas análises dos indicadores relacionados a infraestrutura, serviços e cursos obtidos através da autoavaliação

Modelagem de problemas de fratura em materiais quase-frágeis pelo E-FEM

In this paper a numerical model with strong discontinuities is presented to address fracture problems in quasi-brittle materials. A non-symmetrical statically and kinematically consistent formulation is implemented. The strong discontinuity in the displacement field is represented using the elemental enrichment finite element method (E-FEM). In other words, the strong discontinuity is introduced into the finite element and the additional degrees of freedom are condensed at the element level, allowing the implementation into existing computational codes. Two constitutive models are used to analyze the behavior of the cracked zone, linear and exponential. The exponential model results are closer to those obtained in experimental data and representative numerical simulations than the linear model.Neste artigo, um modelo numérico com descontinuidades fortes é apresentado para abordar problemas de fratura em materiais quase frágeis. É implementada uma formulação não simétrica estaticamente e cinemáticamente consistente. A descontinuidade forte no campo de deslocamentos é representada usando o método do elemento finito com enriquecimento elementar (E-FEM). Em outras palavras, a descontinuidade forte é introduzida no elemento finito e os graus de liberdade adicionais são condensados em nível de elemento, permitindo a implementação em códigos computacionais existentes. Dois modelos constitutivos são utilizados para analisar o comportamento da região fissurada, um linear e outro exponencial. Os resultados do modelo exponencial estão mais próximos dos obtidos em dados experimentais e simulações numéricas representativas do que o modelo linear

A Literatura Guineense: Contribuição para a Identidade da Nação

Tese de doutoramento em Letras, área de Línguas e Literaturas Modernas, especialidade de Literaturas dos Países Africanos de Língua Oficial Portuguesa, apresentada à Faculdade de Letras da Universidade de CoimbraNeste trabalho sobre Literatura Guineense em língua portuguesa, temos como objetivo descrever, analisar e discutir a construção da identidade nacional de um jovem país, fragilizado por sucessivos golpes de Estado. A viagem pelas obras dos autores que constituem o nosso corpus permitiu apreender os temas e as estratégias discursivas que cada escritor, cada poeta, foi produzindo, em prol de um objetivo comum: a construção de uma identidade nacional no meio de uma pluralidade étnica. Procuramos perceber pela voz dos seus poetas, a convivência entre a História e a poesia guineense em língua portuguesa, desde 1951, ano do primeiro poema datado de Vasco Cabral, até à atualidade. Há muito que o espaço literário guineense deixou de ser um vazio. Esta Literatura possui, desde o seu começo, uma função didática, informativa e formativa que procurou, através das tradições e culturas, resgatar a identidade nacional. A Literatura Guineense está muito enraizada em referências históricas e na expressão das vozes plurais das várias etnias, que povoam este pequeno território. Procuramos compreender, por um lado, de que modo os autores guineenses, através das suas estórias ficcionadas, se têm antecipado à História. Por outro lado, encontrar, pela mão destes mesmos autores, os motivos que os desanimam e os principais interessados na criação de um Estado-Nação “falhado”. Refletimos o lugar da língua portuguesa, enquanto herança do invasor e espaço de interferências criadoras. Na terceira e última parte, procuramos destacar, das obras que constituem o nosso corpus, as marcas da identidade nacional, o seja, o que distingue os guineenses, no geral: os seus modelos educacionais, os símbolos e rituais, os heróis e os sabores da Guiné-Bissau.On this work about Guinean Literature in the portuguese language, we aim to describe, analyze and discuss the construction of national identity of a young country, weakened by successive coups. The journey through the works of authors who constitute our corpus allowed the learning of themes and discursive strategies that every writer, every poet, was producing, searching a common objective: building a national identity in the middle off an ethnic plurality. We seek to understand throught the voice of their poets the coexistence between history and poetry in the portuguese language, since 1951, the year of the first poem dated of Vasco Cabral, until today. The Guinean literary subject is no longer an empty space. This Literature has since its beginnings, a didactic, informative and formative role that it sought, through the traditions and cultures redeem national identity. And is truly rooted in historical literature references and expression of plural voices of the various ethnic groups of this small territory. We seek to understand, on first hand, how the Guinean authors, through their fictional stories, have anticipated the history. On the other hand, find, by these same authors, the reasons that discourages them and the main mentors of creating of a nation-state "failed". We reflect the portuguese language’s place, as a legacy of the space invaded and creative interferences. In the third and final part, we seek to emphasize, through the works that constitute our corpus, the marks of national identity, is what distinguishes the Guineans in general: their educational models, symbols and rituals, heroes and flavors of Guinea-Bissau

Otimização da produção de biodiesel a partir de óleo de coco babaçu com aquecimento por microondas

As reações sob aquecimento por microondas geralmente apresentam significativa redução no tempo de reação e elevados rendimentos. Portanto, o objetivo desse trabalho foi adaptar um forno de microondas doméstico de forma adequada e segura para realização de reações de transesterificação, e otimizar o processo de produção de biodiesel por microondas usando óleo de coco babaçu como matéria prima. Para este fim, foi usado um planejamento composto central no qual se variou o tempo de irradiação, concentração de KOH e razão óleo:metanol. Análises estatísticas foram feitas para avaliarem a significância do modelo usado. As condições experimentais ótimas foram: razão óleo:metanol, 8,59, concentração de KOH, 2,19%, tempo de irradiação, 70 segundos, dando rendimento de aproximadamente 100%.Reactions under microwave heating present reduced reaction times and larger yields. Therefore, this work is aimed at adapting a domestic microwave oven and optimizing the transesterification reaction used in biodiesel production with microwave heating, using babaçu coconut oil as raw material. It was used a central composite design for varying irradiation time, KOH concentration, and oil:methanol ratio. Statistical analyses were performed in order to assess the significance of the model used. The optimized experimental conditions were: oil:methanol ratio, 8.59; KOH concentration, 2.19 %; and irradiation time, 70 seconds, giving an yield of approximately 100% regarding esters formation.FAPEM

Band edge states of the (n)=0 gap of Fibonacci photonic lattices

ABSTRACT: The stationary and normally incident electromagnetic modes in Fibonacci lattices with generating layers of positive and negative indices of refraction are calculated by a transfer-matrix technique. It is shown that the condition for constructive interference of reflected waves is fulfilled when the ratio of optical paths in positive and negative media are given by the golden ratio. Furthermore, in the long-wavelength limit, it is demonstrated that the edges of the (n)=0 gap are the frequencies satisfying the conditions (E)=0 and (u)=0

Photonic band structure evolution of a honeycomb lattice in the presence of an external magnetic field

ABSTRACT: A standard plane-wave expansion technique is used to investigate the evolution of the photonic band structure of a two-dimensional honeycomb lattice composed by cylindrical shell rods with dielectric permittivities 1 and 2, and embedded in a background with permittivity 3. We have considered the effect of dispersive dielectric responses as well as the influence of an externally applied magnetic field aiming to obtain efficient tunable bandgaps. Present results suggest that a combination of a doped semiconductor constituent with an anisotropic geometry, which breaks symmetry and unfolds degeneracies, provides an efficient realization of photonic systems with tunable bandgaps