71 resultados para CHARCOAL


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An archeological artifact can be seen as a chronological element, which helps to determine the age of certain society and to understand the thinking, values and the way of life of this society. Thus, the classification of archeological artifacts is one of the approaches used to study the cultural system of antique societies trying to reconstruct their history. The "Centro de Museologia, Antropologia e Argueologia (CEMAARQ)" of the "Unesp Univ Estadual Paulista" in Presidente Prudente, São Paulo state, Brazil, develops projects within this context (identification and preservation). This is the case of the archeological site named "Lagoa São Paulo-02" discovered in 1993 at the margins of the Parana river in the region of Presidente Epitacio city, São Paulo state, Brazil. This site has ceramic fragments of different shapes and sizes that have a strong influence of traces of the Guarani culture, which is one of the Brazilian native populations. These samples were basically characterized via micro-Raman scattering and Fourier transform infrared absorption (FTIR) spectroscopies. The main objective was to identify the pigments used in the manufacture of the ceramic artifacts and to analyze the composition of the ceramic body to understand how the artifacts were made. Three pigments were found: red, black and white. For the red pigment were identified characteristic bands of hematite, an iron oxide found in the red rocks of the river banks that were eroded by water. The black pigment, probably, is due to the use of vegetal charcoal, which is found in nature as the product of burning organic material such as wood. For the white pigment, the FTIR spectra suggested the use of kaolin, either in the ceramic body or in the proper white pigment, due to the presence of the characteristic bands of the kaolinite. Complementary, the additives applied as anti-plastics were identified as charcoal and quartz, being the latter found in the rocks present in the archeological site. (C) 2010 Elsevier B.V. All rights reserved.

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An analytical procedure has been developed for simultaneous determination of solvent mixture vapors to enable evaluation of occupational exposure. To determine the desorption efficiency the volatile components of the solvent mixtures were generated from a glass tube filled with glass wool. This device is easy to prepare and use. These vapors were then collected in activated charcoal tubes and analyzed by capillary gas chromatography. The method was tested with a mixture of 22 solvents, including aliphatic and aromatic hydrocarbons, alcohols, ethers, esters, and ketones, oil at low concentrations. All the components were defected. When a 99: 1 mixture of carbon disulfide-dimethylformamide was used for desorption the efficiency was > 75% for most of the solvents.

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Entre as maiores aplicações da cultura de tecidos de plantas está a propagação massal de mudas de plantas ornamentais. O objetivo deste trabalho foi avaliar o cultivo in vitro de um híbrido de orquídea Brassocattleya em diferentes concentrações de NH4NO3, KNO3 e BAP. Foram utilizadas sementes do híbrido de orquídea Brassocattleya 'Pastoral' e as plantas foram cultivadas em meio MS com redução pela metade das fontes de P, Mg e Ca e adição de 25 g L-1 de sacarose, 100 mg L-1 de mio-inositol, 1,5 g L-1 de carvão ativo e 6,5 g L-1 de ágar-ágar, sendo o pH ajustado para 5,8. Como tratamentos foram usados quatro concentrações dos sais NH4NO3 e KNO3 (2x; 1x; ½ e ¼ do meio MS) e três concentrações de BAP (0,0; 0,5 e 1,0 mg L-1). Avaliou-se a multiplicação, o crescimento em altura, massa fresca e seca, além dos teores de açucares redutores na massa seca das mudas. Observou-se grande influência das doses de NH4NO3 e KNO3 sobre o crescimento em altura das mudas, massa fresca e seca e teores de açucares redutores em Bc. ('Pastoral' x Auto). A dose de ¼ da utilizada no meio MS promoveu aumento significativo do crescimento das plantas. Para multiplicação, houve melhor resultado com a dose de ½ dos sais NH4NO3 e KNO3 utilizados no meio MS e 1,0 mg L-1 de BAP.

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Ultrastructural and cytochemical characteristics of mononuclear phagocyte cells in turtles are not well described in the literature, especially in Phrynops hilarii. Thus, the aim of this study was to evaluate these characteristics in the mononuclear phagocyte cells and their phagocytic activity in vitro using the turtle P. hilarii as an experimental animal model. The six turtles used in the study were observed in two seasons, spring and summer. Results showed that mononuclear phagocytes incubated only in diluted solution or with colloidal charcoal have cytoplasm phagolysosomes. The cells incubated with colloidal charcoal and further exposed to the cytochemical reaction for acid P-glycerophosphatase, showed cytoplasm phagolysosomes filled by charcoal particles being digested and some positively stained lysosomes. Acid P-glycerophosphatase positive reaction was present in lysosomes and inside the phagolysosomes, while acid cytidine 5-monophosphatase staining occurred in lysosome surroundings. A positive reaction for trimetaphosphatase was also found inside phagolysosomes. In conclusion, the presence of lysosomal enzymes like trimetaphosphatase and cytidine-5'-sodium monophosphate, in the circulating blood of P. hilarii indicate that mononuclear phagocytes participate in the phagocytic process by gathering many phagocytic cells and forming multinucleated giant cells, which probably have a role in the blood clearance process. (C) 2008 Elsevier Ltd. All rights reserved.

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This work presents experimental information relevant to the combustion of biomass in a bubbling fluidized bed. The biomass distribution in a fluidized bed was studied through tests performed in a cold bed, while the volatiles released in the biomass pyrolysis, the burning rate of the resulting charcoal, and the combustion control regime, were studied through tests performed in a high temperature bed.Visual examination of photographs taken from a transparent walls bed, with a rectangular cross-section, showed that the large fuel particles, typical of biomass processing, were distributed in the bubbles, in the splash zone, and in the emulsion phase. The occurrence of biomass in the emulsion phase was favored by burning biomass particles of greater density and smaller size-expetimentally determined in each case. Decreasing the fuel particle size improved the biomass distribution inside the bed. The same was accomplished by increasing the superficial gas velocity as high as possible, compatibly with the acceptable elutriation.Burning tests showed that the biomass fuels have the advantage of reaching the diffusional regime at temperatures that can be lower than 1000 K, which ensures that the biomass fuels burn in a stable regime. (C) 2007 Elsevier B.V. All rights reserved.

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Adição de carvão ativado e giberelina no meio de cultura podem proporcionar melhores condições no desenvolvimento de embriões imaturos de citros. Objetivou-se avaliar o efeito de carvão ativado e GA3 (ácido giberélico) no cultivo de embriões imaturos provenientes do cruzamento entre laranjeira 'Pêra Rio' x tangerineira 'Poncã'. Após 118 dias da polinização, frutos imaturos, com 3 a 4 cm de diâmetro, foram coletados, suas sementes removidas e tratadas com álcool (70%) por cinco minutos, hipoclorito de sódio (2%) por 20 minutos e, posteriormente, lavadas três vezes em água destilada e autoclavada. em condições assépticas, os tegumentos das sementes foram separados, os embriões globulares excisados e inoculados em tubos de ensaio contendo 15 mL do meio MT, acrescido de carvão ativado (0; 0,5; 1; 1,5 e 2 g L-1) e GA3 (0; 0,01; 0,1; 1 e 10 mg L-1). Após a inoculação, os embriões permaneceram por 90 dias em sala de crescimento a 27+1ºC, fotoperíodo de 16 horas e irradiância de 32 mmol m-2 s-1. Maior comprimento da parte aérea foi obtido em meio MT, acrescido de 0,1 e 1 mg L-1 de GA3, combinado com 2 g L-1 de carvão ativado. Maior comprimento do sistema radicular, massa da matéria fresca e número de folhas de plântulas foram obtidos em meio MT, acrescido de 0,01 mg L-1 de GA3, na ausência de carvão ativado. A adição de carvão ativado influenciou na concentração de ácido giberélico acrescido no meio de cultura.

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A series of studies was conducted to establish a methodology for the accurate and efficient determination of betaine in different feed ingredients. The final methodology involves an extraction step in which the feed sample is heated for 3h in a methanolic KOH solution using a Goldfisch apparatus. Impurities are removed by the addition of activated charcoal and concentrated (36%) HCl. After centrifugation the extractant is passed through a strong cation exchange resin (Dowex 50W-X12, H+). The betaine retained in the column is eluted with 1.5 N HCl. A 2 nil aliquot of the elute is air dried and reconstituted with 1 ml of deionised water. HPLC separation with a cation exchange column (Partisil SCX-10) is used for the separation of betaine from other compounds. The mobile phase is kept constant at 50mm KH2PO4 in water, and eluted compounds are detected by UV absorbance (200nm). The flow rate is maintained at 1.5ml min(-1). This assay is very accurate over the range of betaine concentrations from 15 to 650 mug ml(-1), with a lower detection limit in feeds of approximately 500 mug g(-1) when 4g of sample is extracted. Recovery assays done with standard betaine hydrochloride and hard red wheat resulted in a consistent recovery of 80%. Betaine content was quantified in several feed ingredients, including alfalfa (1.77 mg kg(-1)), wheat (3.96 mg kg(-1)), wheat middlings (4.98 mg kg(-1)) and poultry meal (0.77 mg kg(-1)). Betaine in corn and soybean meal was not detectable by this method, even when 16g of sample was used (<125 mg kg(-1)). Betaine present in several feed ingredients should influence choline supplementation to animal feeds and may have implications for human health. (C) 2002 Society of Chemical Industry.

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Several clean-up procedures which included the use of glass chromatography columns (silica gel, alumina, Florisil, silanized Celite-charcoal), Sep-Pak cartridges and standard solutions were compared for the determination of the following N-methylcarbamate (NMC) insecticides: aldicarb, carbaryl, carbofuran, methomyl and propoxur. According to recovery results of the compounds after elution in a glass column, the most efficient systems employed 4.6% deactivated alumina and a silanized Celite-charcoal (4:1) as adsorbents, using dichloromethane-methanol (99:1) and toluene-acetonitrile (75:25) mixtures, respectively, as binary eluents. The recoveries of the compounds studied varied from 84 to 120%. Comparable recoveries (75-100%) for Sep-Pak cartridges in normal phase (NH2, CN) and reversed phase (C-8) were observed. Different temperatures were tested during the concentration step in a rotary evaporator, and we verified a strong influence of this parameter on the stability of some compounds, such as carbofuran and carbaryl. Recovery studies employing the best clean up procedures were performed at the Brazilian agricultural level in potato and carrot samples; Validation methodology of the US Food and Drug Administration was adapted for the N-methylcarbamate analysis. Their recoveries ranged between 79 and 93% with coefficients of variation of 2.3-8%. (C) 1998 Elsevier B.V. B.V.

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A competitive enzyme-linked immunosorbent assay (ELISA) method for carbaryl quantitation in crop extracts was validated by liquid chromatography (LC) with diode array detection (DAD). For this purpose, six crops (banana, carrot, green bean, orange, peach and potato) were chosen for recovery and reproducibility studies. The general sample preparation included extraction with methanol followed by liquid-liquid partitioning and clean-up on Celite-charcoal adsorbent column of the vegetable extracts. ELISA samples consisted of a diluted LC extract in assay phosphate buffer (pH 7.5). The potential effect of methanol in these samples was evaluated. It was observed that a maximum content of 10% methanol present in the assay buffer could be tolerated without expressive losses in the ELISA performance. Under these conditions, a IC50 similar to 1.48 mu g l(-1) was obtained. A minimum matrix effect with a 1:50 dilution of the methanolic extracts in assay buffer was noticed, except for green bean samples that inhibited completely the assay. For the vegetable extracts, the ELISA sensitivities varied from 3.9 to 5.7 mu g l(-1), and good recoveries (82-96%) with R.S.D.s ranging from 5.7 to 12.1% were found. An excellent correlation between the LC-DAD and ELISA techniques was obtained. The confirmation of the carbaryl in less concentrated samples was achieved by LC-mass spectrometry interfaced with atmospheric pressure chemical ionisation. The [M + H](+)= 202 and [M + H-57](+)=145 ions, equivalent to the protonated molecular and l-naphthol ions, respectively, were used to carbaryl identification in these samples. (C) 1998 Elsevier B.V. B.V. All rights reserved.

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Different growing media were compared as to water adsorption and water loss, at Jaboticabal, SP, Brazil, through a three-year period. The objective was to recommend substrates other than tree fern fiber for cultivation of epiphytic orchids. Two treatments of each substrate were used in each sampling: materials stored in laboratory (without use) and materials exposed to conditions of orchid cultivation under laths (used). Generally, the substrates without use adsorbed less water than used substrates. When materials without use were compared, the tree fern fiber retained initially the greatest quantity of water and the blocks of pressed coconut bark, the smallest. However, these blocks gained a great capacity of water adsorption after being used. Charcoal added to the growing media did not cause significant alterations in the studied characteristics. In terms of water relations, the best growing media to substitute the tree fern fiber were composed by blocks of pressed coconut bark or by mixtures of this material with charcoal or Eucalyptus grandis bark. Bark of E grandis alone or in mixture with charcoal did not give good results.