665 research outputs found
Local Isometric immersions of pseudo-spherical surfaces and evolution equations
The class of differential equations describing pseudo-spherical surfaces,
first introduced by Chern and Tenenblat [3], is characterized by the property
that to each solution of a differential equation, within the class, there
corresponds a 2-dimensional Riemannian metric of curvature equal to . The
class of differential equations describing pseudo-spherical surfaces carries
close ties to the property of complete integrability, as manifested by the
existence of infinite hierarchies of conservation laws and associated linear
problems. As such, it contains many important known examples of integrable
equations, like the sine-Gordon, Liouville and KdV equations. It also gives
rise to many new families of integrable equations. The question we address in
this paper concerns the local isometric immersion of pseudo-spherical surfaces
in from the perspective of the differential equations that give
rise to the metrics. Indeed, a classical theorem in the differential geometry
of surfaces states that any pseudo-spherical surface can be locally
isometrically immersed in . In the case of the sine-Gordon
equation, one can derive an expression for the second fundamental form of the
immersion that depends only on a jet of finite order of the solution of the
pde. A natural question is to know if this remarkable property extends to
equations other than the sine-Gordon equation within the class of differential
equations describing pseudo-spherical surfaces. In an earlier paper [11], we
have shown that this property fails to hold for all other second order
equations, except for those belonging to a very special class of evolution
equations. In the present paper, we consider a class of evolution equations for
of order describing pseudo-spherical surfaces. We show that
whenever an isometric immersion in exists, depending on a jet of
finite order of , then the coefficients of the second fundamental forms are
functions of the independent variables and only.Comment: Fields Institute Communications, 2015, Hamiltonian PDEs and
Applications, pp.N
Avaliação de sorgo biomassa visando a produção de bioenergia.
O objetivo deste trabalho foi caracterizar o potencial agronômico de linhagens de sorgo biomassa visando à geração de energia. O ensaio foi implantado no ano agrícola de 2013/2014, em Sete Lagoas-MG, com semeadura realizada no final do mês de janeiro de 2014. O delineamento experimental foi em blocos casualizados, com 3 repetições e 10 genótipos de sorgo. As parcelas experimentais foram constituídas por 2 fileiras de cinco metros, espaçadas de 0,70m. As avaliações foram feitas em uma fileira central de cada parcela e as características avaliadas foram florescimento, altura de plantas (AP), produção de massa verde total (PMV), produção de massa seca total (PMS). Os dados de PMV e PMS foram convertidos para t.ha-1. Híbridos de sorgo biomassa, sensíveis ao fotoperíodo, apresentaram ciclo médio de seis meses e porte alto (superior a 4m) que refletiu em alto potencial produtivo de biomass
Physicochemical properties of Butter cheese from Marajó manufactured with buffalo milk and cow milk.
This study aimed to evaluate the physicochemical characteristics, texture and color parameters of the artisanal Butter cheese from Marajó, manufactured with partial substitution of buffalo milk for cow milk. Four formulations were elaborated: B100 (100% buffalo milk); B80 (80% buffalo milk + 20% cow milk); B70 (70% buffalo milk + 30% cow milk) and B60 (60% buffalo milk + 40% cow milk). Three replicates were performed. The partial substitution of 20%, 30% and 40% of buffalo milk caused the reduction of fat in 16.2%, 21.6% and 25.4%, and protein in 5.2%, 5.7%, and 6%, respectively, with decrease of elasticity, cohesiveness, gumminess and chewiness, but had no influence on the hardness. Moisture had significant and strongly negative correlation with elasticity, cohesiveness, gumminess and chewiness. Fat and protein had significant and strongly positive correlations with elasticity, cohesiveness, gumminess and chewiness. Significant differences were found for color variables L*, a*, b* and ho. The increase in cow milk concentration increased the yellowgreenish tonality, with an emphasis in yellow tones
Microkinetic analysis of ethanol to 1,3-butadiene reactions over MgO-SiO 2 catalysts based on characterization of experimental fluctuations
Microkinetic analysis of ethanol to 1,3-butadiene reactions over MgO-SiO2 catalysts was performed based on the detailed characterization of experimental fluctuations, taking into account the influence of the reaction temperature and catalyst properties on ethanol conversion and product selectivities. The obtained results show that both reaction temperature and catalysts properties affected experimental fluctuations significantly. The local microkinetic information contained in the covariance matrix of experimental fluctuations indicated the change of the rate-limiting step as reaction temperature increased: from 300 to 400 °C, the rate-limiting step was identified as the acetaldehyde condensation, while at 450 °C, ethanol dehydrogenation step limits the 1,3-butadiene production
Desempenho e avaliação de cultivares de sorgo sacarino em Sete Lagoas-MG.
O sorgo sacarino possui grande potencial para a produção de açúcares e etanol, e também se destaca pela disponibilidade de matéria-prima no período de entressafra da cana-de-açúcar, quando ocorre ociosidade nas usinas. Dessa forma, o objetivo do trabalho foi realizar avaliação do desempenho agronômico das cultivares: BRS 511, CV 198, V82393, V82392, CMSXS629, CMSXS647, CMSXS646, CMSXS644, CMSXS630, BRS509, CMSXS643, V82391, BRS 508, BRS 506, Sugargraze, CV 568, para a recomendação dessas quanto ao seu potencial para a produção de etanol. O experimento foi implantado em blocos casualizados com três repetições, e espaçamento entre linhas de 0.70 m, em que foram avaliadas as características de florescimento, altura de planta, produção de massa verde, extração de caldo e sólidos solúveis totais. As cultivares que mais se destacaram para produção de massa verde e teores de sólidos solúveis foram CMSXS629, CMSXS646, BRS508 e BRS511, semelhantes à cultura da cana-de-açúcar, possuindo muito potencial para a produção de etanol de 1ª geração
Evaluation of thermal and non-thermal processing effect on non-prebiotic and prebiotic acerola juices using 1HqNMR and GC - MS coupled to chemometrics.
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Realistic loophole-free Bell test with atom-photon entanglement
The establishment of nonlocal correlations, obtained through the violation of
a Bell inequality, is not only important from a fundamental point of view, but
constitutes the basis for device-independent quantum information technologies.
Although several nonlocality tests have been performed so far, all of them
suffered from either the locality or the detection loopholes. Recent studies
have suggested that the use of atom-photon entanglement can lead to Bell
inequality violations with moderate transmission and detection efficiencies. In
this paper we propose an experimental setup realizing a simple atom-photon
entangled state that, under realistic experimental parameters available to
date, achieves a significant violation of the Clauser-Horn-Shimony-Holt
inequality. Most importantly, the violation remains when considering typical
detection efficiencies and losses due to required propagation distances.Comment: 21 pages, 5 figures, 3 table, to appear in Nature Com
Correlações genotípicas e análise de trilha em sorgo sacarino visando a produção de etanol.
Este trabalho teve o objetivo de avaliar as correlações genotípicas e a análise de trilha em cinco caracteres na cultura do sorgo sacarino (Sorghum bicolor L. Moench). Os caracteres estudados foram: altura média, em metro (ALT); produtividade de massa verde, em ton/ha (PROD); teor de sólidos solúveis totais, em graus brix (BRIX), teor de sacarose no caldo, em porcentagem (POL); produção de etanol, em l/ha (ET). O caracter (ET) foi considerado a variável independente. O experimento foi realizado em blocos casualizados em três repetições. Considerando a produção de etanol, em l/ha (ET), como componente independente, as variáveis Teor de sacarose (POL) e produtividade (PROD) mostraram valores condizentes de coeficientes de trilha aos apresentados nas correlações genotípicas. Os caracteres sólidos solúveis totais (BRIX) e altura (ALT) mostraram valores discordantes entre os coeficientes de trilha, considerando os efeitos diretos sobre ET com as correlações genotípicas, evidenciando assim a grande importância do estudo da análise de trilha para os caracteres utilizados em um programa de melhoramento genético de plantas
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