7 resultados para Processo frutícola pós-colheita
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
ARAUJO, Afranio Cesar de et al. Caracterização socio-econômico-cultural de raizeiros e procedimentos pós-colheita de plantas medicinais comercializadas em Maceió, AL. Rev. Bras. Pl. Med, Botucatu, v. 11, n. 01, p.81-91, 2009. Disponível em:
Resumo:
ARAUJO, Afranio Cesar de et al. Caracterização socio-econômico-cultural de raizeiros e procedimentos pós-colheita de plantas medicinais comercializadas em Maceió, AL. Rev. Bras. Pl. Med, Botucatu, v. 11, n. 01, p.81-91, 2009. Disponível em:
Resumo:
Leptospirosis is a worldwide zoonosis of considerable medical and economical importance that affects humans in both urban and rural contexts, as well as domestic animals and wild fauna. Leptospira interrogans is the causative agent and is transmitted to humans by indirect contact with contaminated soil or water. The clinical syndromes include sub clinical infection, self-limited anicteric febrile illness, and severe and potentially fatal illness, known as Weil´s syndrome. In developed countries, leptospirosis is related to occupational or recreational activities while in developing countries, outbreaks occur during floods. In those regions, traditional strategies to prevent the transmission are difficulties to be implemented because of costs and lack of community acceptance. In addition, no efficient vaccine is available for human use. Several studies have suggested that chemoprophylaxis with doxycycline pre and post-exposure may be effective to prevent leptospirosis. Leptospirosis has been reported in rural areas of the State of Rio Grande do Norte, Brazil since 1985 in rice farmers who present the anicteric illness. The disease cause great social and economics impact. The study was conducted in São Miguel where an epidemic of leptospirosis in rice farmers was reported. The main objective was to determine the efficacy of doxycycline in preventing Leptospira exposure. A taxa de soroprevalência de leptospirose na população estudada antes e após a colheita foi de 14,2% (n=22) e de 16.6% (n=27) respectivamente. Anti-Leptospira serology was determined for 61 subjects in two instances, pre and post-exposure to potential contaminated water. There was an increased risk of 29.0 per cent in acquiring infection for individuals that did not use doxycycline. In addition, an increased risk of 30.0 % observed in farmers who did not use protection when exposed to Leptospira. The adhesion to preventive chemoprophylaxis was 55.7%. Therefore doxycycline, under specific circunstances appears to be an effective alternative to protect against leptosprirosis infection. A large sample composed of individuals to adhere to preventive therapy is needed to define time, dosage and length of use of doxycycline in this area
Resumo:
Hard metals are the composite developed in 1923 by Karl Schröter, with wide application because high hardness, wear resistance and toughness. It is compound by a brittle phase WC and a ductile phase Co. Mechanical properties of hardmetals are strongly dependent on the microstructure of the WC Co, and additionally affected by the microstructure of WC powders before sintering. An important feature is that the toughness and the hardness increase simultaneously with the refining of WC. Therefore, development of nanostructured WC Co hardmetal has been extensively studied. There are many methods to manufacture WC-Co hard metals, including spraying conversion process, co-precipitation, displacement reaction process, mechanochemical synthesis and high energy ball milling. High energy ball milling is a simple and efficient way of manufacturing the fine powder with nanostructure. In this process, the continuous impacts on the powders promote pronounced changes and the brittle phase is refined until nanometric scale, bring into ductile matrix, and this ductile phase is deformed, re-welded and hardened. The goal of this work was investigate the effects of highenergy milling time in the micro structural changes in the WC-Co particulate composite, particularly in the refinement of the crystallite size and lattice strain. The starting powders were WC (average particle size D50 0.87 μm) supplied by Wolfram, Berglau-u. Hutten - GMBH and Co (average particle size D50 0.93 μm) supplied by H.C.Starck. Mixing 90% WC and 10% Co in planetary ball milling at 2, 10, 20, 50, 70, 100 and 150 hours, BPR 15:1, 400 rpm. The starting powders and the milled particulate composite samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) to identify phases and morphology. The crystallite size and lattice strain were measured by Rietveld s method. This procedure allowed obtaining more precise information about the influence of each one in the microstructure. The results show that high energy milling is efficient manufacturing process of WC-Co composite, and the milling time have great influence in the microstructure of the final particles, crushing and dispersing the finely WC nanometric order in the Co particles
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico
Resumo:
The mesoporous materials has been an special attention, among them was discovered in the 1990´s the mesoporous molecular sieve of SBA-15 type. The good features of the SBA- 15 makes this material very promising in catalysis, however, due to the absence of native active sites, it has low catalytic activity. In this way, different metals and oxides have been included in this molecular sieve as a means of introducing active sites and increase its catalytic activity. Among the oxides that are being researched, there is the niobium oxide, which presents strong acid sites and exists in abundance. Brazil is the largest producer of the mineral. On the other hand, the production of biofuels has been desired, but it requires the development of new catalysts for this purpose. The aim of this work was to develop silicate of niobium by impregnation and by new synthesis method for application in the cracking of moringa oil. The methodology consisted of inserting the niobium oxide either by postsynthesis process using wet impregnation and direct insertion. For direct insert a new method was developed for pH adjustment, being tested different pH, and the pH 2.2 was used different ratios of Si/Nb. The materials were characterized by different techniques such as: XRD, N2 adsorption, SEM, EDS, UV-visible, TG/DTG, DSC, TEM, acidity by thermodesorption of n-butilamine and FTIR. After this part of the catalysts developed by the two methods were tested in the thermocatalytic cracking of moringa oil, being used a simple distillation. All silicates of Niobium obtained showed a highly ordered structure, having high specific areas, good distribution of pore diameters, beyond present a morphology in the form of fibers. In the catalysts after synthesis was observed that the niobium inserted has so as octahedrally and tetrahedrally coordinated, demonstrating that there were also oxides formed on the external surface of SBA-15. The materials obtained in the direct synthesis are only tetrahedrally coordinated. The new synthesis method of pH adjusting by using the buffer solution for it, proved to be very efficient for the production of such materials, because the materials obtained showed characteristics and structures similar to the molecular sieve of SBA-15 type. Among the pH tested the material that presented better characteristics was synthesized at pH 2.2. The application of these materials in catalytic cracking showed a higher formation of organic liquids when compared to thermal cracking, in addition to significantly reducing the acidity and residues formed, demonstrating that the use of silicates of Niobium increases both the conversion and the selectivity of the products.
Resumo:
Leptospirosis is a worldwide zoonosis of considerable medical and economical importance that affects humans in both urban and rural contexts, as well as domestic animals and wild fauna. Leptospira interrogans is the causative agent and is transmitted to humans by indirect contact with contaminated soil or water. The clinical syndromes include sub clinical infection, self-limited anicteric febrile illness, and severe and potentially fatal illness, known as Weil´s syndrome. In developed countries, leptospirosis is related to occupational or recreational activities while in developing countries, outbreaks occur during floods. In those regions, traditional strategies to prevent the transmission are difficulties to be implemented because of costs and lack of community acceptance. In addition, no efficient vaccine is available for human use. Several studies have suggested that chemoprophylaxis with doxycycline pre and post-exposure may be effective to prevent leptospirosis. Leptospirosis has been reported in rural areas of the State of Rio Grande do Norte, Brazil since 1985 in rice farmers who present the anicteric illness. The disease cause great social and economics impact. The study was conducted in São Miguel where an epidemic of leptospirosis in rice farmers was reported. The main objective was to determine the efficacy of doxycycline in preventing Leptospira exposure. A taxa de soroprevalência de leptospirose na população estudada antes e após a colheita foi de 14,2% (n=22) e de 16.6% (n=27) respectivamente. Anti-Leptospira serology was determined for 61 subjects in two instances, pre and post-exposure to potential contaminated water. There was an increased risk of 29.0 per cent in acquiring infection for individuals that did not use doxycycline. In addition, an increased risk of 30.0 % observed in farmers who did not use protection when exposed to Leptospira. The adhesion to preventive chemoprophylaxis was 55.7%. Therefore doxycycline, under specific circunstances appears to be an effective alternative to protect against leptosprirosis infection. A large sample composed of individuals to adhere to preventive therapy is needed to define time, dosage and length of use of doxycycline in this area