Abstract Brazil has an extremely limited railroad network compared to other developed and developing countries. There are projects to expand this mesh. Knowing that the cost of implementing a railroad is high, research for solutions that allow cost reduction is of great importance. But the parameters of the materials used in the subgrade and sub-ballast layers are from other countries, which can cause the cost to increase to meet these parameters. Through strength parameters and mineralogical analysis, it is possible to use or not fine tropical soils as a layer of railway pavement. A critical analysis of the standards that are used to scale and/or verify whether a particular soil can be used in these layers was undertaken. For this, the following tests were performed: Granulometry, Atterberg Limits, Compaction, California Support Index (CBR or ISC), Expansion, MCT Classification Test (Miniature, Compacted, Tropical), Dynamic Triaxial and X-Ray Diffraction. From the results, it could be seen that although one of the soils is thin, it presented satisfactory results in relation to the use in layers of the railway pavement. It was verified that it is necessary to use more modern tests, focusing on mechanistic dimensioning for dimensioning pavement layers.

Abstract The granulometric range used has a direct influence on the life of the ballast layer when subjected to the load generated by rail traffic. However, in Brazil, we have only two size ranges to be used. The publications related to the subject matter under study express the need for a continuous grain size strip, different from the ones usually used in our railways. This more continuous band would provide less deformation and a reduction of degradation, granting a longer ballast life. To verify the influence of granulometry, a Dynamic Ballast Test Equipment was used to simulate railway traffic. The results show that if we use a more uniform granulometry, a direct influence on the deformation and the breakage index is evidenced, and consequently, a shorter useful life. The study highlights the need to study continuous granulometric bands for the rail ballast.

Abstract The growing concern in minimizing the disorderly disposal of waste in nature has been influencing measures that seek to give new environmentally sustainable and economically viable purposes for these materials. The use of steel slag aggregate in road paving emerges as an alternative for reducing the storage of this material in industrial yards, as well as contributing to a significant reduction in the cost of building a flexible road pavement. This study aimed to verify the technical feasibility of using ferronickel slag as an aggregate in the composition of hot mix asphalt. To this end, physical, chemical, mineralogical and environmental characterization tests of ferronickel slag were performed. The asphalt mixtures were dosed in accordance with the Marshall methodology, using the DNIT Range C with the use of ferronickel slag in the granulometric portions corresponding to the coarse aggregate, fine and filler, and the petroleum asphalt cement (PAC) 50/70. Based on the results, it can be stated that ferronickel slag demonstrates technical feasibility to be used as an aggregate in the composition of hot mix asphalt, meeting the requirements established by Brazilian standardization. In addition, it is an excellent environmental alternative because it uses a material previously treated as an environmental liability, avoiding the exploration of new natural deposits of stone aggregates.

Abstract The reutilization of waste is a valuable alternative for the preservation of natural resources and the environment. In this sense, Basic Oxygen Furnace (BOF) steel slag is one of the most residues generated in steel the industry. It is estimated that for each ton of steel produced, about 150 kg of steel slag is generated in the BOF process. Generally, the newly produced BOF steel slag is volumetrically unstable, presenting expansive characteristics, and for this reason, its application should be based on stabilization studies. The main objective of this research was to analyze the chemical stabilization process of BOF steel slag by means of carbonation of the material. For this purpose, an experimental method based on hydration and carbonation in 2-meter high slag piles, moistened with sprinklers and instrumented with leaf wetting, temperature, precipitation and carbon dioxide content sensors was used. A control stack was also set up to accompany the stabilization process through the conventional procedure, in which the material is disposed of in large stacks and subjected to the weather conditions for long periods. The laboratory campaigns were developed in the laboratories of the Federal University of Ouro Preto. Thus, through the results obtained, it was possible to conclude that the stabilization method based on hydration and carbonation for the BOF steel slag was efficient, reducing the free lime content to values well below those prescribed internationally.

Abstract The present research had as its basic objective to contribute with the improvement in the quality control evaluation of the compacting process in road works. The real contribution of the survey is to establish an innovative way of controlling the compaction process in the field, with employment of the Humidity versus Rigidity and the Humidity versus Elasticity Module curves, turning the methodology faster and more efficient than the conventional procedures. In fact, to date, the compacting control procedures contemplate methods that are inaccurate and limited by several constraints, rendering the technique unfeasible and time consuming, in detriment of the work schedule. Thus, this study proposes to define a rational correlation criterion between the geotechnical characterization with results obtained in the laboratory using conventional methods and the elastic parameters obtained by applying the rigidity meter of compacted soils, based on a statistical treatment of data concerning the infrastructure of experimental road and railway sections. The results obtained in the research were the correlation curves for Humidity versus Rigidity, and for Humidity versus Elasticity Module, for the material of the deposit, with the corresponding equations. Thenceforth, with the correlation curves, it will be much easier to obtain the moisture content that the soil requires on the earthworks. By measuring the modulus of elasticity or rigidity through the stiffness meter of compacted soils, the respective curve checks if the value of the soil moisture content is compatible with the variation of the moisture content in the project.

Abstract In nature, metal ores such as iron, lead, aluminum and others are found in an impure state, sometimes oxidized and mixed with silicates of other metals. During casting, when the ore is exposed to high temperatures, these impurities are separated from the molten metal and can be removed. The mass formed by these compounds is slag. Slag is the co-product of the smelting of ore to purify metals. It may be considered a mixture of metal oxides, but may also contain metal sulphites and metal atoms in their elemental form. After it is reprocessed to separate the metals contained, the co-products of this process can be used in cement, rail ballast, road paving and various other purposes. The objective of this research work is the presentation of the chemical and mineralogical characterization tests of the silicon-manganese iron slag with the purpose of reusing the co-product as rail ballast. X-ray diffraction tests, quantitative chemical analyzes, scanning electron microscopy and free lime content were prepared for these characterizations. The results of these tests showed the technical feasibility of using slag as rail ballast.

Resumo O artigo tem como objetivo conhecer as ferramentas tecnológicas disponíveis, em seis escolas públicas do Estado da Bahia, tomando como referência os municípios de Eunápolis e Lauro de Freitas. A partir de uma pesquisa qualiquantitativa e de incursões bibliográficas, elaborou-se um questionário online que foi respondido pelos gestores escolares, abordando questões, como: quantidade, qualidade, acesso e utilização por professores e alunos, de recursos tecnológicos computacionais e midiáticos, em contexto de ensino/aprendizagem. Os resultados obtidos apontam para uma série de contradições no uso dos equipamentos tecnológicos nas escolas, exigindo uma redefinição do Programa.

Abstract This article aims to meet the technological tools available, in six public schools of the State of Bahia, taking as a reference the municipalities of Eunápolis and Lauro de Freitas. From a quantitative research and bibliographical incursions, has drawn up a questionnaire that was answered by the school manager, addressing issues such as: quantity, quality, access and use by teachers and students of computational media, and technological resources in teaching/learning context. The results point to a number of contradictions in the use of technological equipment in schools, requiring a redefinition of the program.

Resumen El artículo tiene como objetivo conocer las herramientas tecnológicas disponibles, en seis escuelas públicas del estado de Bahía, tomando como referencia los municipios de Eunápolis y Lauro de Freitas. De una investigación cuantitativa y bibliográficas incursiones, ha elaborado un cuestionario que fue respondido por los directores de escuela, cuestiones tales como: cantidad, calidad, acceso y uso por parte de profesores y estudiantes de medios de cómputo y recursos tecnológicos en el contexto de enseñanza y aprendizaje. Los resultados apuntan a una serie de contradicciones en el uso de equipamiento tecnológico en las escuelas, que requieren una redefinición del programa.

Estudamos os níveis séricos da IL-2, IFN-g e do TNF-a de portadores da doença de Chagas em suas diferentes formas clínicas, compensados e descompensados. As citocinas medidas nos 91 pacientes com a forma crônica da doença não diferiram dos níveis de 13 indivíduos controle. Não houve diferença estatística entre os 17 portadores da forma indeterminada da doença e os portadores de cardiopatia insipiente (n = 4), de cardiopatia bem estabelecida (n = 62), da forma digestiva (n = 4) ou da forma mista (n = 4) da doença. Os níveis séricos de TNF foram indetectáveis e IFN-g não diferiu nas diferentes formas clínicas ou com a severidade da doença. No entanto, encontramos níveis mais elevados de IL-2 nos 25 pacientes não-contrololados do que nos 66 pacientes bem compensados (p < 0,001). Sugerimos que a dosagem de IL-2 possa servir como indicadora da necessidade de terapêuticas mais agressivas nestes pacientes.

We studied the serum levels of IL-2, IFN-g and TNF in different clinical forms of Chagas' disease and in patients clinically compensated and decompensated. Cytokines measured in 91 patients with the chronic form of the disease did not differ from those of 13 normal individuals, suggesting the absence of activation of the TH1 pattern of lymphocyte response. There were no statistical differences among the 17 patients in the indeterminate form of the disease, the patients presenting either early (n = 4) or well-developed signs of cardiomyopathy (n = 62), the digestive (n = 4) or the mixed (n = 4) forms of the disease. Serum TNF was undetectable and IFN-g levels did not differ between clinical forms and severities of Chagas' disease. However, we found IL-2 higher levels in the 25 non-controlled patients than in the 66 controlled individuals (p < 0,001). We suggest that IL-2 dosage may be useful as an indicator of the need for more aggressive procedures.