Effect of the fluorination of DLC film on the corrosion protection of aluminum alloy (AA 5052)

It is presented a study conducted on the physical and electrochemical properties of fluorinated a-C:H films deposited onto a commercial aluminum alloy (AA 5052). The coatings were deposited from mixtures of 91% of acetylene and 9% of argon by plasma immersion ion implantation and deposition technique, PIIID. Total gas pressure was 44 Pa and deposition time (t(dep)) was varied from 300 to 1200 s. The depositing plasmas were generated by the application of radiofrequency power (13.56 MHz, 100W) to the upper electrode and high voltage negative pulses (2400 V. 300 Hz) to the sample holder. Fluorine was incorporated in a post-deposition plasma treatment (13.56 MHz, 70W, 13 Pa) generated from sulfur hexafluoride atmosphere. Chemical structure and composition of the films were investigated using infrared reflectance/absorbance spectroscopy and X-ray photoelectron spectroscopy. The corrosion resistance of the layers was determined by electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution, at room temperature. Films presented good adhesion to the substrates and are classified as hydrogenated amorphous carbon (a-C:H) with oxygen traces. Fluorine was detected in all the samples after the post-deposition treatment being its proportion independent on the deposition time. Film thickness presented different tendencies with t(dep), revealing the variation of the deposition rate as a function of the deposition time. Such fluorinated a-C:H films improved the corrosion resistance of the aluminum surface. In a general way the corrosion resistance was higher for films prepared with lower deposition times. The variation of sample temperature with t(dep) was found to be decisive for the concentration of defects in the films and, consequently, for the performance of the samples in electrochemical tests. Results are interpreted in terms of the energy delivered to the growing layer by ionic bombardment. (C) 2010 Elsevier B.V. All rights reserved.

Pion interferometry and resonances in pp and AA collisions

We study the sensitivity of pion interferometry in pp and pp collisions at ISR energies to the resonance abundance. We show that those data are not compatible with the full resonance fractions predicted by the Lund model. The preliminary S+S and O+Au data at 200 A GeV are, however, not incompatible with the Lund predictions, although their sensitivity to resonances is significantly weaker than in the pp/pp case. © 1992.

Avaliação da atividade mutagênica do resíduo sólido de uma fábrica de confecções de meias e lingerie em ensaios com Salmonella typhimurium

Cancer is one of the most hazardous effects to human health caused by the exposition to chemical agents. The search for new technological solutions in the industrial field led to a rapid increase in the productive sector, causing the workers to be exposed to millions of potentially toxic agents, substances potentially harmful to health. This study presents the mutagenic activity of sweepings from a sock and lingerie factory in Araraquara-Brazil, assayed with Salmonella typhimurium. All the extracts from the factory had mutagenic on activity the YG1024 strain, which is extremely sensitive to detect the mutagenic activity of the arilhydroxilamines, nitroarenes and aromatic amines. The extracts were non-mutagenics for the strains TA100 and TA98. The analysis of the mutagenicity of industrial residues is highly important because employees that participate in the production are directly exposed to those agents, as well as to the environment where the garbage is deposited.

The role of coarse intermetallics in the localized corrosion behaviour of AA 2024-T3 in low concentrated chloride media

Aluminium alloy (AA) 2024-T3 is an important engineering material due to its widespread use in the aerospace industry. However, it is very prone to localized corrosion attack in chloride containing media, which has been mainly associated to the presence of coarse intermetallics (IMs). In this work the corrosion behaviour of aluminium alloy 2024-T3 in low concentrated chloride media was investigated using microscopy and electrochemical methods. SEM observations have shown that intermetallics with the same nominal composition present heterogeneous reaction rates, and that both types of coarse IMs normally found in the AA 2024-T3 microstructure corrode. Moreover, EDS analyses have shown important compositional changes in the corroded IMs, evidencing the selective corrosion of their more active constituents and the onset of an intense oxygen peak, irrespective to the IM nature. TEM/EDS observations on non-corroded samples have evidenced the heterogeneous composition within the IMs. On the other hand, the results of the electrochemical investigations, in accordance with the SEM/EDS observations, have evidenced that IMs corrosion dominates the electrochemical response of the alloy during the first hours of immersion in the test electrolyte. © 2009 by NACE International.

Fertilizantes orgânicos e resíduo de bauxita na disponibilidade de nutrientes e nutrição da cana-de- açúcar irrigada com água potável e residuária

The objective of this study was to evaluate the effect of organic fertilizers (urban solid waste and swine manure) as a source of nutrients and residue from bauxite processing as a corrective of soil acidity, in area cultivated with sugar cane irrigated with potable water and served in the availability of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S) levels in the soil and plants. For this experiment was carried out in pots, using a Alfisol, assessing the availability of the elements in the 0-20 cm layer and the concentration of these nutrients in the leaves of sugarcane. The data showed that the residues increased the concentrations of Ca and Mg in soil, as the concentration of K was not changed and S was not detected, due to the low concentration in the soil. In the leave +1 of sugarcane the residue of bauxite increased levels of N, P, K, Ca and Mg (15.68, 1.73, 10.43, 3.50 and 1.08 g kg-1, respectively). The application of urban solid waste and swine manure also increased the levels of N, K and Ca (11.56, 9.18 and 2.81 g kg-1, respectively). The quality of irrigation water did not alter the availability of P, K, Ca, Mg and S in the soil as well as the levels of these macronutrients in the plant.

Temperatura, escarificação mecânica e substrato na germinação de sementes das palmeiras juçara e açaí

The propagation of 'juçara' and 'açaí' is done by seeds, but there is a great desuniformity in the germination process. In this way, the objective of this study was to verify the effect of temperature, mechanical scarification and substrate on seed germination of both species. Two experiments were conducted in a completely randomized design, with four replications each consisting of 25 seeds. The first was conducted with 14 treatments in factorial scheme 7 x 2, seven temperatures (20, 25, 30, 35, 20-30 and 25-35 °C and natural condition), with and without mechanical scarification. The second was constituted of eight treatments in factorial scheme 4 x 2, four substrates (sand, vermiculite, coconut fiber and soil + manure), with and without mechanical scarification. Seeds of 'juçara' palm present the highest mean percentage and germination speed index in alternating temperatures of 20-30 and 25-35 °C and natural condition and in substrates sand, vermiculite and coconut fiber. Temperatures of 30, 35, 20-30 and 25-35 °C and natural condition in all substrates tested were the most favorable condition for 'açai' seeds. The scarification of the seeds was favorable to the germination process of 'juçara' whereas the seeds of açaí does not need to be scarified.

Determinação de resíduo hormonal na carcaça de tilápia do nilo (Oreochromis niloticus) após reversão sexual

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A ressonância magnética no estudo da desintegração de comprimidos marcados com açaí (Euterpe oleracea)

Pós-graduação em Biologia Geral e Aplicada - IBB

Desenvolvimento de um produto tipo hambúrguer à base de carne de frango (Gallus gallus) e resíduo de soja, fermentado com Lactobacillus acidophilus CRL 1014

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Valorização de resíduo de processamento de farinha de mandioca (manipueira) por acetificação: Cassoni Vanessa. -

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise físico-química e energética do resíduo da terra diatomácea utilizada como auxiliar de filtração na indústria de cerveja

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

Caracterização da qualidade de efluente e a possível utilização do resíduo como fonte energética

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

Análise econômico-energética de utilização de resíduo industrial florestal para geração de energia térmica: um estudo de caso

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

Uso do resíduo da produção de farinha de mandioca (Crueira) na produção de álcool fino

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

Resíduo de laranja: estudo da cinética de secagem das sementes e influência da temperatura na qualidade do óleo

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE