467 resultados para Hexafluoreto de enxofre


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Particularmente de gases industriais, biogás e demais condições que exijam a purificação de gases antes de sua emissão para a atmosfera, visando a remoção de H~ 2~S, através da reação de oxidação deste gás com uma solução de íons Fe^ 3+^ produzidos por células imobilizadas de Acidithiobacillus ferrooxidans, uma bactéria quimioautotrófica e acidofílica, oxidante de ferro e formas reduzidas de enxofre. Como resultado do processo de oxidação do H~ 2~S pelos íons Fe^ 3+^ ocorre a produção de enxofre elementar (elemento recuperável no processo) e de íons Fe^ 2+^, os quais são re-oxidados pela bactéria à íons Fe^ 3+^ . Este reagente retorna então ao sistema para um novo ciclo de oxidação do H~ 2~S.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A study was conducted to evaluate the feces+urine produced per animal (FUPA), dry matter, mineral matter, organic matter, nitrogen, phosphorus, potassium and sulfur in feces of gilts fed diets with increasing levels of ractopamine (0, 5, 10 and 15 mg kg-1 of diet). A total of 468 finishing gilts were allotted into 36 pens. In two days of each week, feces and urine were daily sampled in four pens per treatment, quantifying the feces+urine. To determine the characterization of feces, two samples per week were taken daily, in nine pens per treatment. It was used a split plot design, considering the ractopamine level as the plot and the weeks as the subplots. There was no reduction in nitrogen amount in feces. An interaction was detected between ractopamine concentrations and weeks for FUPA and phosphorus, potassium and sulfur in feces. Ractopamine addition in diets for gilts has reduced the feces+urine production and nitrogen and phosphorus excretion. Higher values estimated for potassium content in feces of animals fed diets with 10 and 15 mg of ractopamine kg-1 were found between the second and third week. Increasing levels of ractopamine from 5 to 15 mg kg-1 promoted higher excretion of sulfur over the weeks of supply.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fruit processing for beverage production purposes is a way of adding value to the raw material and of raising the farmer s income by increasing the demand. Thus the objective of this work was the production of fermented West Indian cherry beverages and their physicochemical and sensory evaluation. The beverages were produced based on the Brazilian legislation for fermented fruit beverages and wine. The fermented beverages were produced from West Indian cherry pulp (pulper) and juice (press) and sweetened with sugar to obtain three types of beverage: dry, semidry and sweet. The beverages were submitted to the following physicochemical analyses: pH, alcohol, reducing sugars, total reducing sugars, total acidity, volatile acidity, fixed acidity, dry extract, reduced dry extract, alcohol to reduced dry extract ratio, free sulphur dioxide, total sulphur dioxide and turbidity. In the sensory analysis, the beverages were assessed using a 9-point hedonic scale, evaluating the attributes of appearance, odour, flavour and overall assessment. The chemical and sensory results were submitted to an analysis of variance and the means compared using Tukey s test (5%). Both the raw materials (pulp and juice) and the different sugar concentrations (dry, semidry and sweet) interfered in the sensory and physicochemical parameters of the fermented West Indian cherry beverages, the tasters showing preference for the sweetened beverages.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Pós-graduação em Microbiologia Agropecuária - FCAV

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In materials science, the search for technological improvements have become one of the main subject of study of researchers. This is especially true in the case of materials with reduced sizes, in the nanometer scale. Important phenomena to be studied in these cases are the desorption and adsorption on two-dimensional materials, such as graphene. These phenomena are of great importance in the study of interactions between organic films, synthesis or catalysis of reactions on surfaces and even in the creation of nanoscale devices [1, 2, 3, 4]. Between the most important topics related to these phenomena are the storage of gases in low-dimensional systems and the study of nanostructured fuel cells or batteries. In this context we used two different parametrizations for the reactive force field ReaxFF to study the potential barriers and reaction barriers of our system. First we made a study about the Reaction Barriers and Energy Barriers for bonds between graphene and the following atoms: sulfur, fluorine, hydrogen, nitrogen and oxygen. It is important to have this information in order to make it possible to understand how these atoms react with the graphene sheet. Subsequently, we calculate reaction barriers for mixed structures where fluorine is a fixed element bonded to graphene and other element is simultaneously bonded to graphene. This other element (N, O, H or S) is varied in its possible relative positions (ortho, meta and para in relation to fluorine in either: the same side and in the opposite side of the graphene membrane)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The lubricant oil used in engines of internal combustion must be, periodically, changed. Its mainly function in the engines is to reduce the friction between the pieces, but its presence also promotes the cleanness and the refrigeration of the equipment. These attributions, at the end of some cycles of operation, make the oil to be dirty, that is, full of contaminating substances such as water, gasoline, diesel, additives, oxidized hydro-carbons and rests of metals, not being recommended, therefore, its discarding in the environment. Thus, all the used lubricant oil that leaves the automobiles engine has been thrust, waiting for a solution. The pollution generated by the discarding of a ton of used oil per day in the soil or in the rivers is equivalent to a domestic sewer of 40 thousand of people. The indiscriminate burning of the used lubricant oil generates significant emissions of metallic oxides, besides other toxic gases, like the dioxin and sulphur oxides. In this context, the mean objective of this essay was to effectuate the rerrefine of the used lubricant oil, aiming the increase of its life cycle and consequently contributing for the reduction of the environmental pollution. According to the used process, it was possible to get a rerrefine oil, of good quality, which physicistchemistries properties are in compliance with the norms of NBR and ASTM