131 resultados para pulsed flame photometric detector


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Este trabalho teve como objetivo identificar e quantificar os constituintes dos óleos essenciais de Illicum verum, Ageratum conyzoides, Piper hispidinervum e Ocotea odorifera, bem como avaliar a toxicidade para o pulgão-verde Schizaphis graminum. A qualificação dos constituintes foi realizada por meio de um cromatógrafo gasoso + espectrômetro de massas, e a quantificação, por um cromatógrafo gasoso + detector de ionização de chama, ambos com uma coluna DB5. O método de hidrodestilação promoveu um rendimento (p/p) de 3,81% para I. verum, 0,46% para A. conyzoides, 2,85% para P. hispidinervum e 0,68% para O. odorífera. Já os componentes majoritários foram: precoceno (87,0%) e (E)-cariofileno (7,1%) para A. conyzoides; (E)-anetol (90,4%), limoneno (2,6%) e metil-chavicol (1,3%) para I. verum; metil-eugenol (81,2%) e safrol (10,6%) para Ocotea odorífera; e safrol (82,5%) e α-terpinoleno (13,4%) para P. hispidinervum. Pelos testes de toxicidade aguda (24 horas) com folhas de sorgo ou papel-filtro contaminados, verificou-se que o óleo de A. conyzoides foi o mais tóxico para o pulgão, com CL50 de 7,13 e 7,08 µL óleo/cm2 respectivamente, seguido por O. odorifera com CL50 de 11,80 e 103,00 µL óleo/cm2 respectivamente; I. verum de 51,80 µL óleo/cm2 em ambos os substratos; e o menos tóxico foi o óleo essencial de P. hispidinervum, com CL50 de 62,50 e 143,00 µL óleo/cm2, respectivamente. Dessa maneira, sugere-se que o uso dos óleos essenciais pode representar uma nova ferramenta em programas de manejo integrado de pragas.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This study aimed to evaluate the potential of CH4 and CO2 in vitro production of soybean hulls, sunflower meal, corn, citrus pulp and corn silage. Four rumen-cannulated sheep were fed diets containing the evaluated ingredients at 40:60 forage:concentrate ratio. The gases produced by samples incubation were measured by injection into a gas chromatograph equipped with flame ionization detector. The experimental design was completely randomized with repeated measures, with three replicates for each evaluated food at four different periods. Under the experimental conditions, we verified different potential gas production among the ingredients. The citrus pulp meal was the ingredient with the greatest potential for CO2production. Corn silage and soybean hulls showed the greatest potential while citrus pulp and sunflower meal showed the least potential for CH4 production, when expressed in mL/g of degraded dry matter; therefore, they can be considered, among the evaluated ingredients, those with the lowest environmental impact.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The present study aimed to evaluate the volatiles profile of red mombin (Spondias purpurea) pulp and its powder produced by spray-drying (SD) as an example to show utility of headspace solid-phase microextraction (HS-SPME) in the analysis of parameters such as the quality and stability of fruit products. Volatiles profiles of the pulp were identified by gas chromatography-mass spectrometry (GC-MS), quantified by gas chromatography-flame ionization detector (GC-FID) and compared to the profile of the powder stored at 0, 60 and 120 days in plastic (PP) or laminated packages (LP). The results showed that the technique was able to identify 36 compounds in the red mombin pulp, 17 out of which have been described for the first time in this fruit, showing that red mombin fresh pulp appears to be unique in terms of volatiles composition. However, only 24 compounds were detected in the powder. This decrease is highly correlated (r(2) = 0.99), at least for the majority of compounds, to the degree of volatility of compounds. Furthermore, the powder stored in PP or LP showed no statistical differences in the amounts of its components for a period of 120 days of storage. Finally, this work shows how HS-SPME analysis can be a valuable tool to assess the quality and stability of fruit products.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The ethyl carbamate is a compound present in most foods yeast-distillates; due to its carcinogenic potential, national legislation has established a limit of 0.150 µg / mL for spirits, so the values above the same, pose a threat to both public health as well for the economic sector by preventing the export of these products. The aim of this work is to provide the optimization of an analytical method employing the technique of gas chromatography equipped with flame ionization detector (FID) to determine the concentration levels of ethyl carbamate in some samples of wine. The use of ethyl acetate as solvent employed in the extraction, the ethyl carbamate present in wine samples proved to be suitable, where Recoveries were between 97.6 to 103.3% (m / m), with a standard deviation for between 0.56 to 3.50%. The concentrations of ethyl carbamate in particular wine samples vary between 3.22 µg / ml and 3.80 µg / mL, with a mean of 3.48 µg / mL. These valuesare all above the limit set by law. Thus, the results indicate the need for changes in the process of wine production, in order to control the levels of the substance

Relevância:

100.00% 100.00%

Publicador:

Resumo:

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

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Hydrogen is known as a clean energy resource. The biological production of hydrogen has been attracting attention as an environmentally friendly processs that does not consume fossil fuels. Cellulosic plant and waste materials are potential resources for fermentative hydrogen production. Cellulose is a linear biopolymer of glucose molecules, connected by β-1,4-glycosidic bonds. Enzymatic hydrolysis of cellulose requires the presence of cellulase. The present study aimed to investigate the efficiency of acid pretreatment on ruminal fluid in order to enrich H2 producing bacteria consortia to enhance biohydrogen rate and substrate removal efficiency. In this study, fermentative hydrogen producers were enriched on cellulose (2g/L) in a modificated Del Nery medium (DNM) at 37ºC and initial pH 7.0 using rumen fluid (10% v/v) as inoculum. To increase the hydrogen production it was added cellulose (10mL) to the medium. The gas products (mainly H2 and CO2) was analyzed by gas chromatography (Shimadzu GC 2010) using a thermal conductivity detector. The volatile fatty acids and ethanol were also detected by GC using a flame ionization detector. Cellulose degradation was quantified by using the phenolsulfuric acid method. Analysis showed that the biogas produced from the anaerobic fermentation contained only hydrogen and carbon dioxide, without detectable methane after acid pretreatment test. On DNM the hydrogen production started with 4 h (5,3 x 105 mmol H2/L) of incubation, and the maximum H2 concentration was observed with 34 h (7,1 x 106 mmol H2/L) of incubation. During the process, it was observed a predominance of acetic acid and butyric acid as well as a low production of acetone, ethanol and nbutanol in all experimental phases. Butyrate accounted for more than 77% of total. As a result of the accumulation of volatile fatty acids (VFAs), the pH value in anaerobic digestion system was reduced to 4,0. On microscopy analyses there were observed rods with endospores. The batch anaerobic fermentation assays performed on anaerobic mixed inoculum from rumen fluid demonstrated the feasibility of H2 generation utilizing cellulose as substrate. Based on the results, it can be concluded that the acid treatment was efficient to inhibit the methanogenic archaea cells present in rumen fluid. The rumen fluid cells present a potential route in converting renewable biomass such as cellulose into hydrogen energy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The use of oxygen to enrich the combustion air can be an attractive technique to increase capacity of an incinerator originally designed to operate with air, If incinerator parameters such as operation temperature, turbulence level and residence time are fixed for a certain fuel supply rate, it is possible to increase the residue consumption rate using enriched air. This paper presents the thermal analysis for operation with enriched air of an aqueous residue experimental incinerator. The auxiliary fuel was diesel oil. The theoretical results showed that there is a considerable increase in the incineration ratio up to approximately 50% of O-2 in the oxidiser. The tendency was confirmed experimentally. Thermal analysis was demonstrated to be an important tool to predict possible incinerator capacity increase. (C) 2005 Published by Elsevier Ltd.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Digital radiography in the inspection of welded pipes to be installed under deep water offshore gas and oil pipelines, like a presalt in Brazil, in the paper has been investigated. The aim is to use digital radiography for nondestructive testing of welds as it is already in use in the medical, aerospace, security, automotive, and petrochemical sectors. Among the current options, the DDA (Digital Detector Array) is considered as one of the best solutions to replace industrial films, as well as to increase the sensitivity to reduce the inspection cycle time. This paper shows the results of this new technique, comparing it to radiography with industrial films systems. In this paper, 20 test specimens of longitudinal welded pipe joints, specially prepared with artificial defects like cracks, lack of fusion, lack of penetration, and porosities and slag inclusions with varying dimensions and in 06 different base metal wall thicknesses, were tested and a comparison of the techniques was made. These experiments verified the purposed rules for parameter definitions and selections to control the required digital radiographic image quality as described in the draft international standard ISO/DIS 10893-7. This draft is first standard establishing the parameters for digital radiography on weld seam of welded steel pipes for pressure purposes to be used on gas and oil pipelines.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A detector system that can measure X-ray intensity in the mammographic range of 22 to 36 kVp (equivalent photon energies ofthe beam between 11 and 15 keV) is presented. It consists of a lithium mobate detector and a high-sensitivity current-to-voltage converter.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)