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Influence of aging time at 850°C on microstructure and corrosion resistance of a cold rolled 2205 duplex stainless steel.
No full textThe effect of aging time at 850°C for 300 s, 600 s, 1800 s, and 84600 s on the microstructural evolution and corrosion resistance of 2205 duplex stainless steel (DSS) was studied after cold rolling up to 60% of reduction. X-ray diffraction, scanning
electron and transmission electron microscopy were used for microstructural characterization. The corrosion behavior was studied
by cyclic potentiodynamic polarization (CPP) and electrochemical impedance technique (EIS) in 3.5% NaCl solution and the susceptibility to sensitization was investigated through the double loop electrochemical potentiodynamic reactivation (DL-EPR) test
in 0.5 M H2SO4 + 0.1 M NaCl + 0.002 M KSCN solution. After cold working, increasing aging time led to an increase in sigma
phase precipitation and a decrease in pitting corrosion resistance. However, the ultrafine microstructure had a beneficial influence
on the self-healing effect in Cr and Mo depleted areas with the increasing of aging time, resulting in higher passivation ability. The
DSS 2205 type was not susceptible to intergranular corrosion for the aged conditions applied
Green hydrogen : decarbonization in mining - review.
No full textIn mining, the system of operation relies on equipment that consumes large amounts of energy. In mine operations, diesel-powered equipment is widely used due to its flexibility, loading capacity, and adaptability to various terrain conditions. However, it presents high diesel oil consumption and high emission rate of greenhouse gasses, mainly carbon monoxide. This paper offers a comprehensive view of the hydrogen effect on diesel engines in the search for renewable energy alternatives that are in tune with the reduction of the environmental impact arising from the use of petroleum-derived fuels. This article presents the energy consumption of diesel-powered trucks in the mining industry. It is followed by a discussion of diesel fuel consumption and exhaust emissions. It adds to the discussion of the technologies for producing hydrogen, the advantages of using them in controlled quantities, and the challenges in production, storage as well as the supply costs. Highlight the carbon-free “green hydrogen”, which presents itself as a promising alternative in its operations to decarbonize the mines, as open pit or underground
A systemic approach to stage machinery : the proscenium theatre flexibility.
No full textTomando o teatro de proscênio como objeto de estudo, este artigo aborda a mecânica cênica sob uma perspectiva sistêmica. Enquanto uma disciplina que compõe
o planejamento de espaços cênicos em edifícios teatrais, a mecânica cênica tem sido flagrantemente negligenciada pela literatura brasileira sobre esse tipo
edificação. A análise dos principais espaços que compõem especificamente o teatro de proscênio e o reconhecimento das funções a eles designadas no
desempenho das atribuições principais desse tipo de edifício permitem estabelecer a notável influência que a mecânica cênica exerce sobre o seu planejamento.
Mais do que isso, é possível afirmar que os elementos da mecânica cênica têm um papel fundamental na garantia da flexibilidade de usos ao teatro de proscênio e,
consequentemente, na manutenção da vida útil funcional da edificação. Tendo isso em vista, a compreensão das relações mantidas entre o edifício e as tecnologias
nele contidas é essencial para a concepção de teatros tecnicamente adequados, capazes de continuar desempenhando suas funções ao longo do tempo. Para a
construção de uma abordagem que facilite o entendimento dessas relações, apoiou-se em um referencial teórico que analisa os edifícios conforme compostos por
camadas construtivas, no qual também se discutem estratégias que visam a flexibilidade dos objetos arquitetônicos, a partir da definição dos seus elementos
permanentes. A partir dos conceitos estudados, foi desenvolvida uma metodologia que sistematizou requisitos, aparatos técnicos e especificidades de organização
dos seus elementos no espaço, como uma forma de orientar a abordagem da mecânica cênica no campo projetual.Tomando el teatro proscenio como objeto de estudio, este artículo aborda la mecánica escénica desde una perspectiva sistémica. Como disciplina que compone la
planificación de los espacios escénicos en los edificios teatrales, la mecánica escénica ha sido descuidada por la literatura brasileña sobre este tipo de edificios. El
análisis de los principales espacios que componen especialmente el teatro proscenio y el reconocimiento de las funciones que se les asignan en el desempeño de
las atribuciones principales de este tipo de edificación permiten establecer la notable influencia que la mecánica escénica ejerce en su planeamiento. Más aún, es
posible afirmar que los elementos de la mecánica escénica desempeñan un papel fundamental en garantizar la flexibilidad de usos del teatro proscenio y, en
consecuencia, en el mantenimiento de la vida útil funcional del edificio. En este sentido, comprender las relaciones que se mantienen entre el edificio y las
tecnologías contenidas en él es fundamental para el diseño de teatro técnicamente adecuados, capaces de seguir desempeñando sus funciones en el tiempo. Para
la construcción de un enfoque que facilite la comprensión de estas relaciones, se apoyó en un marco teórico que analiza los edificios como compuestos de capas
constructivas, en el que también se discuten estrategias que apuntan a la flexibilidad de los objetos arquitectónicos a partir de la definición de sus elementos
permanentes. A partir de los conceptos estudiados, se desarrolló una metodología que sistematizó requisitos, aparatos técnicos y especificidades de organización de
sus elementos en el espacio, como forma de orientar el abordaje de la mecánica escénica en el campo del diseño
Rheological parameters of mixed Brazilian Cerrado fruits sugar-free preserves : the effect of body agents.
No full textThe aim of this study was to evaluate the effect of the bodying agents
(erythritol, sorbitol, xylitol, and polydextrose) and their mixtures on the preparation
of mixed Brazilian Cerrado fruit preserves (marolo, soursop, and sweet passion fruit).
Mixture design was used for product optimization and the preserves were evaluated by
texture profile, stress relaxation test, and uniaxial compression test. The research data
were analyzed using regression equations on SAS software. The results indicated that
the rheological parameters were affected by the body agents. Erythritol should not be
used as an isolated component because it provoked changes in the properties of the
final product (harder and brittle preserves); xylitol and sorbitol made preserves more
elastic, cohesive, and more fragile; and polydextrose showed a synergistic effect with
erythritol for rupture deformation and lesser effects for hardness, adhesiveness, and
gumminess
Notes on images of women who stare at dead girls : gaze, body and enunciation in Sharp Objects and The Killing.
No full textObservo as protagonistas e as meninas assassinadas nos seriados The Killing e Sharp Objects. A partir desses corpos, exploro as posições das personagens nos produtos audiovisuais e reflito sobre: olhares femininos em tela; corpos sobre os quais as práticas discursivas constroem olhares; e modos dessa enunciação. Mergulho na materialidade e na narrativa, em uma leitura crítica feminista com procedimentos de análise fílmica. Percebo como essas vidas são organizadas ao redor da violência.I observe the protagonists and the murdered girls in the series The Killing and Sharp Objects. From these bodies, I explore the characters' positions in audiovisual products and reflect on: female looks on screen; bodies on which discursive practices build perspectives; and modes of this enunciation. I dive into materiality and narrative, in a feminist critical reading with film analysis procedures. I perceive how these lives are organized around violence
The effect of SnO2 surface properties on CO2 photoreduction to higher hydrocarbons.
No full textSeveral photocatalysts have been developed for applications in
reduction reactions, including tin oxide-based semiconductors.
Although its band structure is unfavorable for CO2 reduction
reactions, strategies to modify its surface properties directly
impacted its activity and selectivity during these reactions.
Here, we analyze the influence of heat treatment and
decoration of SnO2 with gold nanoparticles on the gas phase
CO2 photoreduction process. In both cases, a deleterious effect
was observed during reactions under UV radiation (with a drop
of 59.81% and 51.45% in CH4 production for SnO2_150°C and
SnO2/Au_cop, respectively, compared to SnO2_cop), which is
directly related to the availability of surface hydroxyl groups
that play a crucial role in CO2 adsorption. Under visible
radiation, the gold plasmonic resonance took place in the
production of methane (0.33 μmolg 1 for SnO2/Au_cop and
0.29 μmolg 1 for SnO2/Au_150°C), with small amounts of
carbon monoxide (0.06 μmolg 1 for SnO2/Au_cop and
0.03 μmolg 1 for SnO2/Au_150°C). These results demonstrate
that, though the SnO2 band structure does not indicate a good
semiconductor for CO2 reduction, its surface characteristics are
responsible for its catalytic activity
Modelagem numérica de elementos sólidos de aço-carbono estrutural, aço inoxidável e liga inconel 718 via método dos elementos finitos.
No full textPrograma de Pós-Graduação em Engenharia Civil. Departamento de Engenharia Civil, Escola de Minas, Universidade Federal de Ouro Preto.O presente trabalho visa a realização das análises numéricas de elementos sólidos relativos ao aço-carbono estrutural, tanto para o aço de média resistência (MR250) quanto para o de alta resistência (AR350); ao aço inoxidável 304 e da superliga inconel 718. Para isso, implementouse computacionalmente uma formulação matemática baseada no Método dos Elementos Finitos (MEF), que utilizou a linguagem de programação FORTRAN, que teve por propósito a obtenção dos valores de tensões, deformações e deslocamentos nodais dos aços e da liga, levando-se em conta que os materiais apresentam comportamentos elástico-lineares. Quanto às análises das tensões, utilizou-se o método de critério de ruptura de von Mises. Para a discretização dos elementos sólidos, foram utilizados os elementos finitos tetraédricos de 4 nós (T4), hexaédricos de 8 nós (H8) e hexaédricos de 20 nós (H20), sendo que cada nó apresenta três graus de liberdade. Utilizou-se também o Método de Gauss-Legendre (Quadratura de Gauss) para a resolução numérica das integrais. Com o intuito de verificar e validar as respostas obtidas a partir do programa computacional implementado, foram realizadas comparações com resultados encontrados na literatura, e em seguida foram feitas as análises numéricas dos materiais. Este trabalho pretende contribuir de forma eficiente para o cálculo de tensões, deformações e deslocamentos em sólidos.The present work aims to carry out numerical analyzes of solid elements related to structural carbon steel, both for medium strength steel (MS250) and for high strength steel (HS350); stainless steel 304 and superalloy inconel 718. For this, a mathematical formulation based on the Finite Element Method (FEM) was computationally implemented, using the FORTRAN programming language, whose purpose was to obtain the values of stresses, strains and nodal displacements of steels and alloys, considering that the materials present elastic-linear behavior. As for the stress analysis, the von Mises failure criterion method was used. For the discretization of solid elements, the finite elements tetrahedral with 4 nodes (T4), hexahedral with 8 nodes (H8) and hexahedral with 20 nodes (H20) were used, with each node having three degrees of freedom. The Gauss-Legendre method (Gauss quadrature) was used for the numerical resolution of the integrals. In order to verify and validate the responses obtained from the implemented computer program, comparisons were made with results found in the literature, and then numerical analyzes of the materials were performed. This work intends to contribute efficiently to the calculation of stresses, strains and displacements in solids
Tapentadol, an opioid as a strategy for the treatment of chronic pain? : a narrative review.
No full textChronic pain affects approximately 30 % of the world population. Tapentadol can be an analgesic option for patients who do not respond adequately to commonly used opioids. This study reviewed the general aspects of Tapentadol pain treatment and its possible association with increased oxidative stress, as well as the benefits of its association with antioxidant substances. The search was carried out in the Medline (Pubmed), Scopus,Web of Science, and Google academic databases, including studies since the registration of the drug in 2008. The selected articles were those related to the use of Tapentadol for chronic moderate to severe pain, but not cancer-related pain, in adults and the elderly. Tapentadol is a μ opioid receptors agonist and inhibits noradrenaline reuptake. Although Tapentadol causes fewer adverse effects than other conventional opioids, studies have shown the induction of oxidative stress by this drug, but without having elucidated the mechanisms
Interventions in writing learning : an experience in the Pedagogical Residence Program.
No full textEste artigo propõe analisar uma experiência de intervenção pedagógica que aconteceu no âmbito do Programa Residência Pedagógica (UFOP/CAPES). O objetivo foi compreender como que uma estudante que já possuía certo domínio da escrita de palavras compostas por sílabas simples, se apropriou da escrita de palavras compostas por sílabas complexas. Ressalta-se que as dificuldades em relacionar os fonemas - grafemas em relações regulares e irregulares de escrita foram trabalhadas a partir de intervenções que tiveram como ponto de partida os resultados de uma avaliação diagnóstica da escrita. Essas intervenções possibilitaram a reflexão da estudante sobre a própria escrita, sobre os erros ortográficos que cometia, assim como o seu desenvolvimento na aprendizagem da escrita alfabética.This article proposes to analyze an experience of pedagogical intervention that took place within the scope of the Pedagogical Residency Program (UFOP/CAPES). The objective was to understand how a student who already had a certain mastery of writing words composed of simple syllables, appropriated the writing of words composed of complex syllables. It is noteworthy that the difficulties in relating phonemes - graphemes in regular and irregular writing relations were worked on from interventions that had as a starting point the results of a diagnostic evaluation of writing. These interventions enabled the student to reflect on her own writing, on the spelling mistakes she made, as well as her development in learning alphabetic writing
Uma leitura a partir do feminismo decolonial da obra Hibisco Roxo, de Chimamanda Ngozi Adichie.
No full textPrograma de Pós-Graduação em Letras. Departamento de Letras, Instituto de Ciências Humanas e Sociais, Universidade Federal de Ouro Preto.A ficção Hibisco roxo, da autora nigeriana Chimamanda Adichie, retrata os efeitos da
colonização britânica na Nigéria. A partir da narradora-personagem, Kambili, o leitor
tem acesso às marcas de violência e injustiças que recaem sobre as personagens,
sobretudo as femininas. Nesse contexto, o principal objetivo dessa pesquisa foi
realizar uma leitura crítica da obra, sob a perspectiva do feminismo decolonial,
expressão criada por María Lugones a partir dos fundamentos de colonialidade do
poder estabelecidos por Aníbal Quijano (2005) e desenvolvida por outras autoras
contemporâneas, como Ochy Curiel (2020), Suzana de Castro (2020), Lélia Gonzalez
(2020), Sueli Carneiro (2011), Oyèrónkẹ́ Oyěwùmí (2021), bell hooks (2020) e Angela
Davis (2017). Assim, procura-se compreender como o livro engendra e questiona a
memória moldada pela colonialidade, tendo como alicerce as vivências das mulheres
retratadas na obra literária. Em seguida, busca-se analisar a formação das principais
personagens femininas representadas no romance adichiano, sendo elas Kambili,
Beatrice, Amaka e Ifeoma, a partir da proposta do feminismo decolonial.The fiction Purple Hibiscos, by Nigerian author Chimamanda Adichie, portrays the
effects of British colonization in Nigeria. From the narrator-character, Kambili, the
reader has access to the marks of violence and injustice that fall on the characters,
especially the female ones. In this context, the main objective of this research was to
carry out a critical reading of the work, from the perspective of decolonial feminism,
expression created by María Lugones based on the foundations of the coloniality of
power established by Aníbal Quijano (2005) and developed by other contemporary
authors, such as Ochy Curiel (2020), Suzana de Castro (2020), Lélia Gonzalez (2020),
Sueli Carneiro (2011), Oyèrónkẹ́ Oyěwùmí (2021), bell hooks (2020) and Angela Davis
(2017). Thus, we seek to understand how the book engenders and questions the
memory shaped by coloniality, based on the experiences of the women portrayed in
the literary work. Next, we seek to analyze the formation of the main female characters
represented in the Adichian novel, namely Kambili, Beatrice, Amaka and Ifeoma,
based on the proposal of decolonial feminism