Efeitos da vibração simultânea nas propriedades mecânicas de juntas de aço ASTM A131 soldadas pelo processo arame tubular (FCAW)

Pós-graduação em Engenharia Mecânica - FEG

Caracterização mecânica e microestrutural do aço MARAGING 300, soldado a plasma e submetidas a reparos

Pós-graduação em Engenharia Mecânica - FEG

Otimização de rotas tecnológicas de processamento e distribuição de resíduos municipais

Pós-graduação em Engenharia Mecânica - FEG

About the thermal stability and pore elimination in the ordered hexagonal mesoporous silica SBA-15

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

Er3+-doped Y2O3 obtained by polymeric precursor: Synthesis, structure and upconversion emission properties

The relentless pursuit for materials containing rare earth ions with photoluminescent properties has led to several studies with applications in the development of new technologies. The main focus of this work is the preparation of Er3+-doped polycrystalline Y2O3 with photoluminescent properties using PEG as an organic precursor and heat-treated at different temperatures. The methodology used in this synthesis is highly attractive due to its high feasibility for improved technology and low cost for preparing materials. The behavior of the viscous resin has been evaluated and the final compounds exhibited the formation of a cubic polycrystalline phase, which is able to support variations in Er3+ doping concentrations up to 10 mol%, without significant changes in the polycrystalline parameters. The values of the nanocrystallite size calculated by Scherrer's equation showed direct dependence on the heat-treatment temperature as well as the Er3+ concentration. Intense emission in the visible region under excitation at 980 nm was attributed to an upconversion phenomenon assigned to the intraconfigurational f-f transitions of Er3+ ions. The upconversion mechanism was investigated and it was demonstrated that the higher intense emission in the red region in comparison to the emission in the green region is related to the crystallite size. The studies about the intensity showed the dependence of upconversion emission of power source, indicating that two-photon are responsible for the green and red photoluminescence. These polycrystalline materials exhibit properties that make them promising for use in solar energy systems, C-telecom band or solid-state laser devices. (C) 2014 Elsevier B.V. All rights reserved.

Supplementation based on protein or energy ingredients to beef cattle consuming low-quality cool-season forages: I. Forage disappearance parameters in rumen-fistulated steers and physiological responses in pregnant heifers

Two experiments evaluated the influence of supplement composition on ruminal forage disappearance, performance, and physiological responses of Angus x Hereford cattle consuming a low-quality cool-season forage (8.7% CP and 57% TDN). In Exp. 1, 6 rumen-fistulated steers housed in individual pens were assigned to an incomplete 3 x 2 Latin square design containing 2 periods of 11 d each and the following treatments: 1) supplementation with soybean meal (PROT), 2) supplementation with a mixture of cracked corn, soybean meal, and urea (68:22:10 ratio, DM basis; ENER), or 3) no supplementation (CON). Steers were offered meadow foxtail (Alopecurus pratensis L.) hay for ad libitum consumption. Treatments were provided daily at 0.50 and 0.54% of shrunk BW/steer for PROT and ENER, respectively, to ensure that PROT and ENER intakes were isocaloric and isonitrogenous. No treatment effects were detected on rumen disappearance parameters of forage DM (P >= 0.33) and NDF (P >= 0.66). In Exp. 2, 35 pregnant heifers were ranked by initial BW on d -7 of the study, allocated into 12 feedlot pens (4 pens/treatment), and assigned to the same treatments and forage intake regimen as in Exp. 1 for 19 d. Treatments were fed once daily at 1.77 and 1.92 kg of DM/heifer for PROT and ENER, respectively, to achieve the same treatment intake as percent of initial BW used in Exp. 1 (0.50 and 0.54% for PROT and ENER, respectively). No treatment effects (P = 0.17) were detected on forage DMI. Total DMI was greater (P < 0.01) for PROT and ENER compared with CON and similar between PROT and ENER (P = 0.36). Accordingly, ADG was greater (P = 0.01) for PROT compared with CON, tended to be greater for ENER compared with CON (P = 0.08), and was similar between ENER and PROT (P = 0.28). Heifers receiving PROT and ENER had greater mean concentrations of plasma glucose (P = 0.03), insulin (P <= 0.09), IGF-I (P <= 0.04), and progesterone (P = 0.01) compared to CON, whereas ENER and PROT had similar concentrations of these variables (P >= 0.15). A treatment x hour interaction was detected (P < 0.01) for plasma urea N (PUN), given that PUN concentrations increased after supplementation for ENER and PROT (time effect, P < 0.01) but did not change for CON (time effect, P = 0.62). In conclusion, beef cattle consuming low-quality cool-season forages had similar ruminal forage disappearance and intake, performance, and physiological status if offered supplements based on soybean meal or corn at 0.5% of BW.

Chemical characteristics and fractionation of proteins from Moringa oleifera Lam. leaves

Moringa oleifera Lam, is a leguminous plant, originally from Asia, which is cultivated in Brazil because of its low production cost. Although some people have used this plant as food, there is little information about its chemical and nutritional characteristics. The objective of this study was to characterise the leaves of M. oleifera in terms of their chemical composition, protein fractions obtained by solubility in different systems and also to assess their nutritional quality and presence of bioactive substances. The whole leaf flour contained 28.7% crude protein, 7.1% fat, 10.9% ashes, 44.4% carbohydrate and 3.0 mg 100 g(-1) calcium and 103.1 mg 100 g(-1) iron. The protein profile revealed levels of 3.1% albumin, 0.3% globulins, 2.2% prolamin, 3.5% glutelin and 70.1% insoluble proteins. The hydrolysis of the protein from leaf flour employing sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (ME) resulted in 39.5% and 29.5%, respectively. The total protein showed low in vitro digestibility (31.8%). The antinutritional substances tested were tannins (20.7 mg g(-1)), trypsin inhibitor (1.45 TIU mg g(-1)), nitrate (17 mg g(-1)) and oxalic acid (10.5 mg g(-1)), besides the absence of cyanogenic compounds. beta-Carotene and lutein stood out as major carotenoids, with concentrations of 161.0 and 47.0 mu g g(-1) leaf, respectively. Although M. oleifera leaves contain considerable amount of crude protein, this is mostly insoluble and has low in vitro digestibility, even after heat treatment and chemical attack. In vivo studies are needed to better assess the use of this leaf as a protein source in human feed. (C) 2013 Elsevier Ltd. All rights reserved.

Rest stops during road transport: Impacts on performance and acute-phase protein responses of feeder cattle

Angus x Hereford steers (n = 42) and heifers (n = 21) were ranked by gender and BW on d 0 of the experiment and randomly assigned to 1 of 3 treatments: 1) no transport and full access to feed and water (CON); 2) continuous road transport for 1,290 km (TRANS), or 3) road transport for 1,290 km, with rest stops every 430 km (STOP; total of 2 rest stops). Treatments were applied from d 0 to 1 of the experiment. Cattle from TRANS and STOP treatments were transported in separate commercial livestock trailers, within a single 2.1 x 7.2 m compartment, but through the exact same route. During each rest stop, STOP cattle were unloaded and offered mixed alfalfa-grass hay and water for ad libitum consumption for 2 h. Upon arrival of STOP and TRANS on d 1, cattle were ranked by sex and BW within each treatment and assigned to 21 feedlot pens (7 pens/treatment; 2 steers and 1 heifer/pen). Full BW was recorded before (d -1 and 0) treatment application and at the end of experiment (d 28 and 29). Total DMI was evaluated daily from d 1 to 28. Blood samples were collected on d 0 (before loading of TRANS and STOP cattle), 1 (immediately after unloading of TRANS and STOP cattle), 4, 7, 10, 14, 21, and 28. Body weight shrink from d 0 to d 1 was reduced (P < 0.01) in CON compared to TRANS and STOP, and reduced in STOP compared to TRANS. Mean ADG was greater (P < 0.05) in CON compared to TRANS and STOP, but similar (P = 0.68) between TRANS and STOP. No treatment effects were detected (P >= 0.18) on hay, concentrate, and total DMI. Mean G: F was greater (P = 0.05) in CON compared to STOP, tended to be greater (P = 0.08) in CON compared to TRANS, and similar (P = 0.85) between TRANS and STOP. Plasma cortisol concentrations were greater (P <= 0.04) in TRANS compared to CON and STOP on d 1, and greater (P = 0.04) in TRANS compared to CON on d 4. Serum NEFA concentrations were greater (P < 0.01) in TRANS compared to CON and STOP on d 1, and greater (P <= 0.05) in TRANS compared to CON on d 4 and 7. Mean plasma ceruloplasmin concentrations were similar (P = 0.19) among treatments. Plasma haptoglobin concentrations were greater (P <= 0.04) in TRANS compared to CON and STOP on d 1, and in STOP compared to CON on d 1. In conclusion, inclusion of rest stops during a 1,290-km transport prevented the increase in circulating cortisol and alleviated the NEFA and haptoglobin response elicited by transport, but did not improve feedlot receiving performance of transported cattle.

Histopathological Changes by the Use of Soft Reline Materials: A Rat Model Study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of the Freeze-Drying Process on the Physicochemical and Biological Properties of Pre-heated Amphotericin B Micellar Systems

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relação nitrogênio não proteico e proteína verdadeira em suplementos na recria de bezerros Nelore

Pós-graduação em Zootecnia - FCAV

Conservação pós-colheita de melões inteiros e minimamente processados

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Preparação e caracterização estrutural, mecânica e anelástica de ligas do sistema Ti-Ta contendo oxigênio intersticial, para uso biomédico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da corrosão em ligas de alumínio utilizadas na indústria aeronáutica

A resistência e o mecanismo de corrosão das ligas de alumínio 2024, 7010, 7050 e 7475 foram estudados em solução de NaCl. Os efeitos do tratamento térmico nas ligas, concentração de oxigênio, pH, adição de oxi-ânions e temperatura do meio constituem algumas das variáveis estudadas. Primeiramente, procedeu-se à caracterização físicoquímica dos materiais através de análise química e metalográfica, mediante microscopia eletrônica de varredura e espectroscopia de energia dispersiva. As ligas 2024, 7010, 7050 e 7475 como recebidas, recozidas e envelhecidas, revelaram a existência de partículas ternárias e quaternárias, constituídas por Al:Cu:Fe e Mg ou Zn. Também foi observado um maior número de partículas pequenas de composição variável situando-se, preferencialmente, nos contornos dos grãos. Os resultados dos ensaios de corrosão em meios aerados e desaerados indicam que o cromato é efetivo como inibidor da corrosão localizada em ambas ligas e que o molibdato somente na liga 7050. O efeito inibidor do tungstato se revela em meio desaerado e é comparativamente menor daquele observado com os outros oxi-ânions. As análises quantitativas de superfície das ligas após os ensaios de imersão indicam que ainda na presença de inibidor, se pites foram nucleados, eles crescem.

Determinação da temperatura de referência T0 da curva mestre na região de transição dúctil-frágil de aços ARBL

Materiais estruturais utilizados no projeto de equipamentos e instalações industriais podem apresentar mudança de seu comportamento à fratura quando se varia a temperatura. Este tipo de comportamento caracteriza-se pela existência de uma curva de transição, onde 3 regiões ficam bem definidas: os patamares inferior e superior e a região de transição. Na região de transição, os resultados experimentais apresentam alto espalhamento e são bastante dependentes da geometria ensaiada. Para solucionar este problema, foi desenvolvido um modelo analítico experimental, que resultou na edição da norma ASTM E1921-97. O trabalho inclui um estudo da influência de diversas rotas de tratamentos térmicos aplicadas em um aço 4130 utilizado pela indústria aeronáutica, um aço de qualidade API utilizado pela indústria petrolífera e um aço da classe A516 atualmente utilizado pela indústria nacional de vasos de pressão, na microestrutura, propriedades mecânicas de tração e tenacidade à fratura. Os resultados mostraram que o aço 4130 A450, apresentou a melhor correlação entre resistência e tenacidade entre as microestruturas pesquisadas. Este comportamento deve estar associado a rota de tratamento térmico aplicada a esta condição. O tratamento de austêmpera possibilita a formação de bainita que, tradicionalmente é conhecida por apresentar elevados valores de tenacidade. O método proposto pela ASTM pode ser considerado viável para as diversas microestruturas pesquisadas ampliando a aplicação da metodologia que recomenda o ensaio apenas para aços ferríticos. No entanto, a metodologia da Curva Mestra em materiais tratados termicamente deve ser conduzida de forma a se estabelecer parâmetros que considerem as modificações microestruturais sofridas pelo material.