Sample records for dissolved materials
from WorldWideScience.org

Sample records 1 - 7 shown.



1

Retenção de poluentes em filtros orgânicos operando com águas residuárias da suinocultura/ Retention of pollutants in organic filters operating with swine confinement wastewater

Brandão, Viviane dos S.; Matos, Antônio T. de; Fontes, Maurício P. F.; Martinez, Mauro A.
2003-08-01

Resumo em português Para aproveitamento das águas residuárias da suinocultura na fertirrigação de culturas agrícolas, principalmente no caso do uso de irrigação localizada, torna-se necessária a remoção dos sólidos em suspensão e de parte dos dissolvidos. Como, para esse tipo de água o uso de filtros convencionais de areia não é possível, torna-se necessário o estudo de materiais alternativos para uso como filtros. Como materiais filtrantes foram avaliadas a casca de arroz, (mais) a casca de frutos do cafeeiro, o bagaço de cana-de-açúcar, o sabugo de milho triturado, a serragem de madeira e o fino de carvão vegetal. As colunas de filtragem foram constituídas de tubos de PVC de 100 mm de diâmetro e comprimento de 600 mm, sendo preenchidas com o material até a altura de 500 mm e com compressão de 12.490 N m-2. Avaliaram-se as alterações químicas e físicas ocorridas no material após seu uso como filtro no tratamento de 15 L de águas residuárias da suinocultura. Os materiais filtrantes que apresentaram maior capacidade de retenção de poluentes foram o bagaço de cana-de-açúcar e a serragem de madeira. Resumo em inglês For the utilization of wastewater from swine confinement in fertigation of agricultural crops, mainly in the case of localized irrigation, it is necessary to remove the suspended solids and some of the dissolved ones. Since the use of conventional sand filters for wastewater is not possible there is a need for a study concerning alternative materials that might be used as wastewater filters. The following filtering materials were evaluated: rice husk, coffee husk, sugarca (mais) ne bagasse, milled corncob, sawdust and fine charcoal. The filtration columns consisting of PVC tubes with 100 mm diameter and 600 mm length were filled with filtering material up to 500 mm height and compression of 12,490 N m-2. Evaluations were performed for the chemical and physical changes occurring in the material following its use as a filter in treatment with swine wastewater. The filtering materials showing a higher retention capacity for the pollutants were the sugarcane bagasse and sawdust.

Scientific Electronic Library Online (Portuguese)

2

Polímeros com condutividade iônica: desafios fundamentais e potencial tecnológico/ Polymers with ionic conductivity: fundamental challenges and technological potential

Silva, Virgínia P. R.; Caliman, Vinicius; Silva, Glaura G.
2005-11-01

Resumo em português Polímeros condutores iônicos ou eletrólitos poliméricos constituídos por um sistema de sal dissolvido em uma matriz polimérica sólida são materiais que apresentam interesse científico e potencial tecnológico. A dissolução de sais em uma matriz polimérica amorfa ou semicristalina sólida leva a estudos sobre intrigantes aspectos estruturais, que podem ser abordados por técnicas físico-químicas diversas tais como RMN, Raman e Espectroscopia de Vida Média de (mais) Pósitrons. Os estudos estruturais são correlacionados com propriedades eletroquímicas visando à utilização desses materiais em dispositivos tais como baterias, supercapacitores e células solares. Grupos brasileiros têm gradativamente ampliado os estudos e aplicações de eletrólitos poliméricos sólidos. Resumo em inglês Ionic conducting polymers or polymer electrolytes prepared with the addition of a soluble salt in a solid polymeric matrix are very important materials, associated with an intense research activity and technological efforts. Structural studies in a system of salt dissolved in an amorphous or semicrystalline solid polymeric matrix can be done with various techniques, such as NMR, Raman and Positron Annihilation Spectroscopy. The structural studies are correlated with elect (mais) rochemical properties in order to evaluate these materials for applications in batteries, supercapacitors and solar cells. Brazilian researchers are contributing to the fundamental research and development of new applications of polymeric electrolytes.

Scientific Electronic Library Online (Portuguese)

3

Decomposição de resíduos sólidos domiciliares e variações na resistividade e cargabilidade

Moreira, César Augusto; Braga, Antonio Celso de Oliveira
2009-09-01

Resumo em português A geofísica aplicada em estudos ambientais é uma alternativa viável e promissora diante da demanda crescente por novas técnicas de investigação, essencialmente na caracterização e monitoramento de áreas contaminadas. Este trabalho apresenta os resultados de aplicação dos métodos de Eletrorresistividade e Polarização Induzida, na análise da área de percolação de chorume proveniente de aterro de resíduos sólidos dispostos em valas com datas de fechamento (mais) programado.Os resultados sugerem uma associação entre anomalias de alta cargabilidade em valas de resíduos fechadas recentemente, enquanto que as anomalias de baixa resistividade independem da idade de fechamento das valas. As áreas com alta cargabilidade provavelmente estão relacionadas à precipitação de Ferro, dissolvido por ataque do chorume no solo e nos materiais metálicos presentes nos resíduos. Resumo em inglês The applied geophysics in environmental studies is a viable and promising alternative forward of the crescent demand for new techniques of investigation, essentially in the characterization and monitoring of contaminated areas. This paper presents the results of the application of the Electrical Resistivity and Induced Polarization methods, in analysis of the area of leachate percolation from municipal solid waste landfill, in ditches with dates of programmed closing. The (mais) results suggest an association among high chargeability anomalies and residues ditches closed recently, while the low resistivity anomalies they are independent of the age of closing. The areas with high chargeability are probably related to the precipitation of iron, dissolved for attack of the leachate in soil and metallic materials present in the residues.

Scientific Electronic Library Online (Portuguese)

4

Inteligibilidade racional e historicidade

Paty, Michel
2005-08-01

Resumo em português UM DOS principais objetivos da ciência é mostrar que "o mundo é inteligível pela razão humana". Esta busca de compreensão racional tem uma história estreitamente ligada à história das ciências, mas também à das técnicas e à da filosofia, assim como à criação científica. Analisamos as relações entre construção social e historicidade, enfatizando a relevância dos conteúdos do conhecimento, os quais não se deixam dissolver nas condições externas de (mais) sua constituição. Toda a riqueza da historicidade pode ser vista na maneira orgânica pela qual estes conteúdos são tecidos a partir de materiais do mundo empírico assimilados em construções racionais. A própria historicidade torna-se-nos inteligível e permite entender as ampliações da racionalidade que possibilitam as aberturas, as invenções e os progressos do conhecimento. Resumo em inglês ONE OF the main purposes of science is to show that "the world is intelligible" by human reason. This attempt at a rational comprehension has an history, which is closely linked to that of sciences, but also to that of techniques and of philosophy, and also with scientific creation. We examine the relationship between social construction and historicity, by putting emphasis on the importance of knowledge contents, that do not let themselves be dissolved in the external co (mais) nditions of their constitution. All the richness of historicity shows itself in the organic way in which these contents are woven from materials of the empirical world assimilated in rational constructions. Historicity itself becomes intelligible to us, and allows us to conceive widenings of rationality that allow opening, invention and progress of knowledge.

Scientific Electronic Library Online (Portuguese)

5

Distribuição geográfica da fauna e flora da Baía de Guanabara/ Geographic distribution of the flora and the fauna of the Guanabara Bay

Oliveira, Lejeune P. H. de
1947-09-01

Resumo em inglês The author studied, the horizontal and vertical distribution of most common part of the flora and fauna of the bay of Guanabara at Rio de Janeiro. In this paper the eulittoral, poly, meso and oligohaline regions were localised and studied; and the first chart of its distribution was presented (fig. 2). The salinity of superficial waters was established through determinations based on 30 trips inside the buy for collecting biological materials. Some often 409 determination (mais) s which were previous reported together with the present ones served for the eleboration of a salinity map of the bay of Guanabara (fig. 1). This map of fig. 2 shows the geographic locations of the water regions. EULITTORAL WATER REGIME — Fig. 3 shows the diagram scheme of fauna and flora of this regime. Sea water salinity 34/1.000, density mean 1.027, transparent greenish waters, sea coast with moderate bursting waves. Limpid sea shore with white sand, gneiss with the big barnacle Tetraclita squamosa var. stalactifera (Lam. Pilsbry. Vertical distributions: barna¬cles layers with a green region in which are present the oyster Ostrea pa-rasitica L., the barnacles Tetraclita, Chthamalus, Balanus tintinnabulum var. tintinnabulum (L.) e var. antillensis Pilsbry in connection with several mollusca and the sea beatle Isopoda Lygia sp. Covered by water and exposed to air by the tidal ritms, there is a stratum of brown animals that is the layer of mussels Mytilus perna L., with others brown and chestnut animals : the Crustacea Pachygrapsus, the little crab Porcellana sp., the stone crab Me-nippe nodifrons Stimpson, the sea stars Echinaster brasiliensis (Mull. & Tr.), Astropecten sp. and the sea anemones Actinia sp. Underneath and never visible there is a subtidal region with green tubular algae of genus Codium and amidst its bunches the sea urchin Lycthchinus variegatus (Agass.) walks and more deeply there are numerous sand-dollars Encope emarginata (Leske). The microplancton of this regime is Ceratiumplancton. POLYHALINE WATER REGIMB — Water almost sea water, but directly influenced by continental lands, with rock salts dissolved and in suspension. Salinity: 33 to 32/1.000. This waters endure the actions of the popular nicknamed «water of the hill» (as the waters of mesohaline and oligohaline regimes), becoming suddenly reddish during several hours. That pheno¬menon returns several times in the year and come with great mortality of fishes. In these waters, according to Dr. J. G. FARIA there are species of Protozoa : Peridinea, the Glenoidinium trochoideum St., followed by its satellites which he thinks that they are able to secret toxical substances which can slaughter some species of fishes. In these «waters of the hill» was found a species of Copepoda the Charlesia darwini. In August 1946 the west shore of the Guanabara was plenty of killed fishes occupying a area of 8 feet large by 3 nautical miles of lenght. The enclosure for catching fishes in the rivers mouthes presents in these periods mass dead fishes. The phenomenon of «waters of the hill» appears with the first rains after a period of long dryness. MESOHALINE WATER REGIME — Fig. 4 shows the the diagramm scheme. Salt or brackish water from 30 to 17/1.000 salinity, sometimes until 10/1.000. Turbid waters with mud in suspension, chestnut, claveyous waters; shore dirty black mud without waving bursting; the waters are warmer and shorner than those of the polihaline regime. Mangrove shore with the mangrove trees : Rhizophora mangle L., Avicennia sp., Laguncularia sp., and the »cotton tree of sea» Hibiscus sp. Fauna: the great land crab «guaimú» Cardisoma guanhumi Latr., ashore in dry firm land. There is the real land crab Ucides cordatus (L.) in wetting mud and in neigh¬ bourhood of the burrows of the fiddler-crabs of genus Uca. On stones and in the roots of the Rhizophora inhabits the brightly colored mangrove-tree-crab («aratu» Portuguese nickname) Goniopsis cruentata (Latreille) and the sparingly the big oyster Ostrea rhizophorae Guild. Lower is the region of barnacles Balanus amphitrite var. communis Darwin and var. niveus Darwin; Balanus tintinnabulum var. tintinnabulum (L.) doesn't grow in this brackish water; lower is the region of Pelecipoda with prepollency of Venus and Cytherea shell-fishes and the Panopeus mud crab; there are the sea lettuce Ulva and the Gastreropod Cerithium. The Paguridae Clibanarius which lives in the empty shells of Gasteropod molluscs, and the sessile ascidians Tethium plicatum (Lesuer) appears in some seasons. In the bottom there is a black argillous mud where the «one landed shrimps» Alpheus sp. is hidden. OLIGOHALINE WATER REGIME — The salinity is lower than 10/1.000. average 8/1.000. There are no barnacles and no sea-beetles Isopods of genus Lygia; on the hay of the shore there are several graminea. This brackish water pervades by mouthes of rivers and penetrates until about 3 kilometers river above. While there is some salt dissolved in water, there are some mud crabs of the genus Uca, Sesarma, Metasesarma and Chasmagnatus. The presence of floating green plants coming from the rivers in the waters of a region indicated the oligohaline waters, with low salt content because when the average of NaCl increases above 8/1.000 these plants die and become rusty colored.

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6

Construção e otimização de um reator de baixo custo para a fotodegradação da matéria orgânica em águas naturais e sua aplicação no estudo da especiação do cobre por voltametria/ Construction and optimization of a low cost reactor for the photodegradation of organic matter from natural waters and its application for the study of copper speciation by voltammetry

Campos, M. Lúcia A. M.; Mello, Lígia C.; Zanette, Dilson R.; Sierra, M. Marta de Souza; Bendo, Anderson
2001-04-01

Resumo em inglês This work describes the construction of a home-made low-cost reactor, using easily available materials, capable of destroying efficiently dissolved organic matter. Just 30 minutes of irradiation were sufficient to destroy more than 99% of the humic acids present in a solution of 4 mg C L-1. Copper speciation was evaluated in natural waters of different salinities to test the reactor's efficiency in destroying organically complexed metal species. The effect of the organic (mais) matter concentration, salinity, dissolved oxygen and temperature in the photo-oxidation process is discussed.

Scientific Electronic Library Online (Portuguese)

7

Avaliação da concentração de mercúrio em sedimentos e material particulado no rio Acre, estado do Acre, Brasil/ Mercury concentration assessment in botton sediments and suspended solids from Acre river, in the State of Acre, Brazil

Mascarenhas, Artur Fernando Silva; Brabo, Edilson da Silva; Silva, Alexandre Pessoa da; Fayal, Kleber de Freitas; Jesus, Iracina Maura de; Santos, Elisabeth C. de Oliveira
2004-01-01

Resumo em português A avaliação dos teores de mercúrio em sistemas aquáticos sem influência direta de fontes antropogênicas conhecidas não tem sido conduzida com freqüência na região Amazônica. Visando contribuir para esclarecer a ocorrência de valores elevados de Hg em peixes consumidos pela população de Rio Branco - AC, o Instituto Evandro Chagas - IEC, realizou um estudo para quantificar os teores de Hg em sedimentos de fundo e material particulado no rio Acre e alguns aflue (mais) ntes, além da caracterização físico-química das águas entre as cidades de Brasiléia e Assis Brasil. As amostras de sedimentos foram peneiradas na fração Resumo em inglês Mercury levels assessment in aquatic systems areas without influences of antropogenic sources have not been well studied in the Amazon region. For the identification of the origin of high values of Hg in fish consumed by population of Rio Branco City - AC, the Evandro Chagas Institute - IEC, studied the mercury levels in sediments, suspended solids and studied also the physical-chemical characterization of waters, in the Acre river and also some in afluents, between Brasi (mais) léia and Assis Brasil cities. Bottom sediments samples were sieved to

Scientific Electronic Library Online (Portuguese)