Estudo da adição de argila expandida na formulação de concretos leves

Lightweight concrete has been the subject of several studies towards the development of new building materials. Emphasis has been given on the particle size effect and nature of aggregates used as raw materials. The present study includes an analysis of the materials that make this kind of concrete, analyzes of mechanical properties such as compressive and tensile strength, in addition to assessments of the interface concrete aggregate/matrix interface, porosity and absorption profile of chloride ions in lightweight concrete based on expanded clay. The experiments were carried out by molding cylindrical samples 100 mm in diameter and 200 mm in height. The dosage experiments were performed without additives or with the addition of minerals: (T1) 1: 2.01: 1.10: 0.78 (T2) 1: 2.00: 1.32 : 0.62 - (T3) 1 :1.93 :1.54: 0.47 (cement : sand : expanded clay 0500 : expanded clay 1506).The water to cement ratio was set to 0.43. Expanded clay minerals with different average particle sizes were used, i.e., 9.5 mm/0500 and 19 mm/1506. The larger aggregate was coated by a glassy layer, yielding lower water absorption characteristics to the concrete. The results showed that the use of light expanded clay aggregates is a technically interesting solution to the production of lightweight concrete for construction applications

Estudo do comportamento plástico, mecânico, microestrutural e térmico do concreto produzido com resíduo de porcelanato

Population growth experienced in major cities, allied to society s need of infra-structure, especially ones related to habitational demands, increases the consumption of construction materials. As a consequence, consumption of natural resources itself. Thus, due to this process, concrete is one of the most produced materials in civil construction. This is also due to the great diversity of its application, easiness in its execution and adequate mechanical performance, as well as low production costs. Following the same tendencies in construction development, the ceramic industry has intensified the production of porcelain ceramic tiles and floors. These are achieved by a fine finishing and receive polishing at the end of the fabrication process. This work researched the use of porcelain residues in polishing for the production of concrete. All of which; due to economical and environmental issues. This process aims to prove adequate destiny for this type of residue, due to environmental issues, incorporating it to the concrete itself; all of which provides economy in consumption of the materials that constitute concrete. Thus, the main characteristics of concrete were investigated through the inclusion of different concentration of the porcelain residue as additional trait element. The residue rates incorporated to the trait varied from 10% to 50% in relation to the cement mass, in the traits with plastic additives and without plastic additives. It is observed that the inclusion of porcelain residue produced a meaningful alteration in the consistency of fresh concrete. This residue has a fine granulometry and it considerably absorbed the water used in the concrete spreading, influencing the way this material is dealt with. Thus, the value of cement striking decreases with the increase of residues present in trait. The maximal incorporation of the residue was of 50%, massively, for the same factor water/initial cement. The use of residues in concrete results in an 40% increase in the compression resistance. It is also proportional to residue concentration of porcelain in the trait. The microstructure was also favored once porosity and concrete absorption decreases with the use of this residue. The parameters demonstrate the quality and durability of the concrete produced with this residue. The use of porcelain residue in concrete composition has not produced meaningful thermal behavior changes. Thermal conductivity, heat capacity and thermal diffusivity have been maintained basically constant

Estudo da incorporação da cal em composições binárias de solo-cimento para produção de tijolos maciços

The use of binders in the soil for the production of solid bricks is an old construction technique that has been used by several civilizations over time. At the same time, the need for environmental preservation and the tendency of scarcity of natural resources make the construction invest in researching new concepts, methods and materials for building systems for the sustainability of their economic activities. Thus arises the need to obtain building materials with low power consumption, capable of reducing the growing housing shortage of rural and urban population. Currently, research has been conducted on this topic to better understand the cementitious and pozzolanic reactions that occur in the formation of the microstructure of the soil-cement when added to other materials such as, for example, lime, and the relationship between microstructure and formed interfaces with the physical, mechanical and chemical analysis in compounds made from these ternary compositions. In this context, this study aimed to analyze the results of the influence of the incorporation of lime to the soil-cement to form a ternary mixture to produce soil-cement bricks and mortar without structural purposes. From the inclusion of contents of 6 %, 8 %, 10% and 12% lime to the soil, and soil-cement mixes in amounts of 2 %, 3 %, 4 % and 5 % were shaped-bodies of -cylindrical specimens to determine the optimum moisture content and maximum dry apparent specific weight. Then they were cured, and subjected to the tests of compressive strength, absorption and durability modified. Compositions obtained the best results in the tests performed on the bodies-of-proof cylindrical served as a parameter for molding of solid bricks, which underwent the same experimental methodology previously cited. The raw materials used, as well as compositions in which the bricks were molded solid, were characterized by physical and chemical tests, X-ray diffraction and scanning electron microscopy. The results obtained in the study indicate that the compositions studied, that showed the best results in terms of compressive strength, water absorption and durability ternary composition was soil, 10 % cement and 2 % lime

Ser professor de português: o que dizem os discursos reguladores, os alunos e os professores no contexto da formação inicial (UMINHO/Portugal e UFRN/Brasil)

The constitution of being a teacher of Portuguese occurs in a dynamic process involving various factors, such as the requirements of regulatory documents, the context of teacher formation, and the configuration of current society, per se. This study is aimed at reflecting on the initial formation of teachers of Portuguese and on official documents that face this formation, raising the following questions: (1) what does it mean to be a Portuguese teacher? (2) what is the vision of the subjects (teachers and students) involved with the formation of teaching the Portuguese Language? (3) how do these individuals deal with official documents? and (4) how do these subjects discourses relate? To understand the context of the formative processes and the knowledge inherent in them, first we take the studies of Garcia (1999) and Tardif (2002) as a theoretical framework, and to understand and interpret the utterances of the interviewees, we were grounded in the writing of Bakhtin (2003), for whom the object of the Humanities, the sciences of man, is the text, since man is, by nature, an expressive being. We situate this study in the framework of qualitative research. It is a multiple case study that focuses on two contexts: formation of teachers of Portuguese at the University of Minho, Portugal, and the Federal University of Rio Grande do Norte, Brazil. The data that make up the research corpus come from documents elaborated by the Ministries of Education of Portugal and Brazil and were adopted by the two teacher formation institutions cited, from individual interviews involving eight trainer teachers (four from each university), and from two group-interviews (one in each institution), done with students in training. Our analysis is divided into three stages: first, document analysis; second, analysis of the discourse of the teachers in both contexts studied; and, third, analysis of the speech of the students in training. It is noteworthy that our purpose in this research was not to come out with a definition like being a teacher of Portuguese is X, but we are interested, above all, in discussing the issues surrounding initial formation, seeking different points of view, and hearing voices coming from different social positions for better understanding our object of study. Our analysis reveals that the initial formation of teachers of Portuguese, both in Portugal and Brazil, occurs in a complex way, under the influence of various factors, including: (a) difficulties in having the individuals involved adapt to the demands of regulatory agencies; (b) students and teachers adequacy to the organizational model of the post-secondary institution; (c) teachers difficulties to deal with the learning problems of students who have limited schooling basis and come from distinct socioeconomic realities; (d) a search for the establishment of methodologies for teaching and learning the Portuguese Language more adequate to reality; and (e) a search for a definition of professional knowledge needed for the teaching practice

Projeto, construção e análise de desempenho de um forno solar alternativo tipo caixa a baixo custo

An alternative box-type solar oven constructed from the scrap iron of a gas conventional cook is presented, which functions principles are the effect greenhouse and the concentration. The oven of the conventional cook is the baking enclosure where the absorber (pot) of the solar oven is located, being re-covered for a glass blade for the generation of the greenhouse effect isolated lateral and having deep its and for a composite the plaster base and EPS. Segments of plain mirrors had been placed in the laterals of the oven for the concentration of the radiation and a reflecting parabola was introduced in the baking enclosure for the exploitation of the incident reflected radiation in the interior of the oven. The oven is mobile to allow one better aiming of exactly in relation to the apparent movement of the sun. The thermal economic and of materials viabilities of the stove in study will be demonstrate The average internal temperature of the absorber was around 150°C and the internal temperature around 120°C. Will demonstrate that its low cost and good thermal performance represents basic characteristics for the viability of large use of such archetype, mainly for cooking the decreases and averages temperatures. One will reveal that the archetype in study is competitive with the box-type solar cooker conceived in the whole world

Assinaturas antropogênicas de elementos maiores e traços em poeira urbana na cidade do Natal-RN

Although there are many studies on urban dust contamination by heavy metals in developed countries, little attention has been paid to this type of study in developing countries, including Brazil. Therefore, a series of investigations were performed to provide signatures of heavy metals in urban dust and assess the potential sources in the city of Natal - RN-Brazil. The fraction of these sediments was studied to pass through a sieve of 63 micrometers. For the study analyzed two groups of samples, one collected in September 2009 at the end of the rainy season (9 samples) and one collected in January 2010 in the dry season (21 samples). So in all, thirty sediment samples were collected from the street. Then, in Fluorescence Spectrometry X-rays were determined major elements SiO2, Na2O, K2O, Al2O3, MgO, P2O5, Fe2O3, MnO, TiO2 and CaO, and trace Rb, Cr, Ni, Cu, Zn, Sr and Pb by an ICPOES was determined Zn, V, Na, K, Ni, Mn, Mg, P, Fe, Cr, Cu, Pb, Ba, Ca and Al from leaching HCl 0.5 mol L-1 . The results of the concentrations of elements show that the greater presence of these occurs in the dry season, except for Si which is higher in the rainy season. Analyses by geoaccumulation Index (IGEO) Enrichment Factor (EF), Contamination Factor (CF), analysis correlation and Hierarchical Cluster, confirm that Zn, Cu and Pb is anthropogenic character. Zinc may be derived from various sources related to motor vehicles or the road signs and street grids. The elements Na, K, Mg and Ca may be related to droplets suspended in air containing cations and anions present in seawater (salty), common in Christmas throughout the year, brought by winds SE-NW. The elements Na, Mg, Ca and K are the most abundant in seawater and were analyzed in this study. This indicates that the source of these additional elements detected by analyzing the contamination factor may be the very sea. Moreover, Ni, Fe, Cr and Ba can be either as a source of anthropogenic geogênica. The source of Ca is different, because it comes in lime and paint (painting guides of buildings and streets) in construction materials, but may also be present in sediments in the fragments of shells or carbonate bioclasts common in the coastal area

Análise das propriedades reológicas de materiais cimentícios associando o conceito de empacotamento de partículas

Pós-graduação em Engenharia Mecânica - FEIS

Estudo de viabilidade de implantação de usina de moagem de entulho com recursos da iniciativa privada no município de Bauru

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Otimização e estudo do comportamento do solo-cimento auto-adensável

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da estabilidade e da capacidade resistente de painéis estruturais do sistema construtivo Light Steel Framing

Pós-graduação em Engenharia Civil - FEIS

Análise dos impactos na construção civil: avaliação do ciclo de vida em chapas de partículas para forros

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

O conceito de competência e o ensino de administração: um estudo multicasos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação de diferentes tratamentos de base aplicados sobre alvenaria de bloco cerâmico na aderência da argamassa: estudo de caso

Este trabalho aborda, de modo científico, o estudo experimental realizado para investigar o mecanismo de aderência de revestimento de argamassa, aplicado sobre alvenaria de blocos cerâmicos, com diferentes tratamentos de base, a saber: (referência 1:3, cimento e areia, em volume - sem cura; 1:3, cimento e areia, em volume - com cura; 1:3+aditivo SBR, cimento e areia, em volume - sem cura; 1:3+aditivo SBR, cimento e areia, em volume – com cura). Foram adotadas três idades distintas (7, 28 e 120 dias) de modo a verificar a evolução da aderência, ao longo do tempo, sendo feitas avaliações tanto em obra (in situ) como ensaios adicionais em laboratório. A determinação da resistência de aderência à tração dos revestimentos de argamassa teve como parâmetro normativo a NBR 13528 (ABNT, 1995) e os resultados foram submetidos à análise estatística de variância. Também foram analisados, aspectos relacionados à influência da estrutura de poros tanto da do emboço como do substrato poroso na aderência, por meio das técnicas de porosimetria por intrusão de mercúrio, porosimetria por dessorção de vapor de água, microscopia eletrônica de varredura (MEV) e difração de raio X. Com base nos resultados obtidos verificou-se que o tratamento de base, o procedimento contínuo da cura úmida e a idade do revestimento são fatores significativos na resistência de aderência, bem como, caso se opte pelo uso do chapisco convencional (1:3, cimento: areia úmida, em volume), torna-se importantel o procedimento contínuo da cura (por um tempo mínimo de 48 horas). No caso de se escolher o uso do chapisco aditivado, este não deve ser submetido a umidades excessivas (cura úmida).

Avaliação dos processos de trabalho dos centros de material e esterização dos hospitais públicos acreditados do estado de São Paulo: um estudo de caso

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

Esverdeando a cadeia de suprimentos: algumas evidências de empresas localizadas no Brasil

The purpose of this article is to identify and analyze how Green Supply Chain Management (GSCM) practices have been adopted by high-tech companies located in Brazil in order to create guidelines to support similar companies to incorporate GSCM initiatives. This research was based on case studies carried out in some representative companies in this sector. The main results are: (a) the supply chain structure can affect both the adoption of GSCM practices and the way they are adopted, (b) the Brazilian environmental legislation and international policies are very important to boost the adoption of GSCM practices, and (c) based on the results obtained, for each one of the six GSCM practices, suggestions for a more appropriate adoption are offered to similar companies.