Adsorção de As, Cu, Pb e Cr na avaliação da capacidade de fixação de metais por resíduo de mineradoras de ferro

Two samples of residues from iron mining plants have been investigated for their retention capacity of As, Cu, Cr, and Pb. The sample with the higher content of iron oxides showed the highest capacity to retain metals. The adsorption affinity series changes from Pb>Cu>Cr~As to As>Pb>Cu>Cr or As>Cu>Cr>Pb, depending on the material and the concentration of the initial solution. In the competitive environment, the Pb adsorption decreases and the As, Cu and Cr adsorption increases. Sequential extraction procedures, carried out after adsorption batch experiments, showed that the most important adsorption process occurs in the oxide fraction and that the major part of the absorbed metal is remobilized from exchangeable and oxide fractions.

Distribuição, fracionamento e mobilidade de elementos traço em sedimentos superficiais

The gold and iron mining activities in the Velhas River yield considerable amounts of suspended solids as well as metals to the hydrological system of the region. The risks were assessed by sequential extraction procedures. They were carried out in sediment samples, aiming to evaluate the presence of Co, Cr, Cu, Ni, Zn and As. Although being at high levels in some parts of the river (e.g. As 527 mg g-1 and Cr 475 mg g-1) they are associated with the residual fraction. Mobility factors were also calculated and show that these species are enriched along the river, e.g. for As 0.02 at the spring and 0.33 at the high course of the river.

Determinação de benzeno, tolueno, etilbenzeno e xilenos em gasolina comercializada nos postos do estado do Piauí

Automotive gasoline consists of a complex mixture of flammable and volatile hydrocarbons derived from crude oil with carbon numbers within the range of 4-12 and boiling points range of 30-225 ºC. Its composition varies with the kind of crude oil and the type of refinery process that they undergone. Aromatics hydrocarbons, in particular benzene, toluene, ethylbenzene and isomeric xylenes (BTEX) are the toxic group constituents presents. GC-FID was employed to quantify these hydrocarbons in 50 commercial gasoline samples from Piauí state. Statistical analysis techniques, such as PCA and HCA were used to analyze the data. Moreover, several validation parameters were evaluated.

Tecnologias de Informação e Comunicação: contribuições para o processo interdisciplinar no ensino superior

Esta pesquisa teve por objetivo analisar como as Tecnologias da Informação e da Comunicação são utilizadas como possibilidade pedagógica para criar um ambiente de aprendizado e que contribuições podem trazer para a interdisciplinaridade prevista nas atuais diretrizes curriculares nacionais do ensino médico. A análise de dados enfatizou os seguintes temas: o projeto político- pedagógico no âmbito das diretrizes curriculares do ensino médico; as tecnologias de Informação e Comunicação no enfoque interdisciplinar; seus entraves na práxis pedagógica. As reflexões preliminares apontaram para os seguintes aspectos: a importância do projeto político pedagógico como norteador dos objetivos do ensino; a integração interdisciplinar como um processo para a melhoria da qualidade do ensino; as TIC como um instrumento facilitador da aprendizagem; as dificuldades dos discentes frente à seleção de informações no ambiente virtual; e, finalmente, o desafio para a formação do médico generalista.

AN APOLOGY OF CARNAP

This paper is focused on dismissive metaontological views about ontology. The paper's first section deals with radical dismissivism: a view which I interpret as Carnap's (1956). The second section approaches moderate dismissivism: a view which I interpret as Hirsch's (2011). My first claim is stated in section three: that there are significant differences between the mentioned authors. However, current literature on metaontology, not only does not emphasize such differences, but also insinuates that they do not exist. The authors I have in mind here are Eklund (2007, 2009) and Bennett (2009). In the fourth section, I compare Carnap's radical dismissivism with Hirsch's moderate dismissivism. My second claim is stated in section five: that Carnap's radical dismissivism is more persuasive than Hirsch's moderate one.

Potencial poluidor de resíduo sólido da Samarco Mineração: estudo de caso da barragem de Germano

Foram estudadas amostras de resíduo sólido da Barragem de Germano, da Samarco Mineração S.A. Tal barragem localiza-se no município de Mariana-MG. Sua principal função é coletar os efluentes do tratamento do minério de ferro processado no Complexo de Germano. Este resíduo foi submetido a testes de classificação, de acordo com as Normas ABNT 10004, 10005, 10006 e 10007. Constatou-se que o resíduo é classe III (inerte) e que os testes mostraram a grande capacidade deste material na retenção de metais pesados e de cromo.

Test of a microlysimeter for measurement of soil evaporation

Quantifying soil evaporation is required on studies of soil water balance and applications aiming to improve water use efficiency by crops. The performance of a microlysimeter (ML) to measure soil evaporation under irrigation and non-irrigation was evaluated. The MLs were constructed using PVC tubes, with dimensions of 100 mm inner diameter, 150 mm depth and 2.5 mm wall thickness. Four MLs were uniformly distributed on the soil surface of two weighing lysimeters conducted under bare soil, previously installed at Iapar, in Londrina, PR, Brazil. The lysimeters had 1.4 m width, 1.9 m length and 1.3 m depth and were conducted with and without irrigation. Evaporation measurements by MLs (E ML) were compared with measurements by lysimeters (E L) during four different periods in the year. Differences between E ML and E L were small either for low or high atmospheric demand and also for either irrigated or non-irrigated conditions, which indicates that the ML tested here is suitable for measurement of soil evaporation.

Influence of irrigation on wheat crop

The use of irrigation has been increased significantly in wheat crops in Brazil. This study aims to evaluate the effect of irrigation on the productivity, on flour technological quality and on the wheat root system. In a field experiment conducted at IAPAR, in Londrina -state of Paraná (PR), Brazil, the IPR 118 cultivar was grown under sprinkler irrigation (Irrigated Treatment) and without irrigation (Non-irrigated Treatment). The productivity was determined by harvesting three samples of 25 m² per treatment. The same samples were used to evaluate the flour technological quality, considering, among other parameters, gluten strength (W). The evaluation of the root system was performed after the harvest, considering a profile of 0 to 45 cm of soil depth, and sampling eight plants per treatment. The profile wall method was used to determine the roots number (RN) and the monolith method to determine the root dry mass (RDM). Irrigation increased wheat productivity in three times, while W was reduced in the flour. Nevertheless, the value of W found in the Irrigated Treatment (249 10-4 J) was sufficient to keep wheat classification as bread type, the same as IPR 118 cultivar is classified. The measured values of RN and RDM were similar or higher for the Non-irrigated Treatment.

Os diagramas de C. S. Peirce para as dez classes de signos

Uma seção da Gramática Especulativa de C.S.Peirce - Dez classes de signos - recebeu, a partir de 1903, um importante tratamento diagramático. Neste artigo, são apresentados e discutidos dois diagramas desenvolvidos por Peirce para as dez classes, incluindo esboços desses modelos.