Aeroacoustics of sawtooth trailing-edge serrations under aerodynamic loading

The impact of aerodynamic loading on a serrated trailing edge is studied experimentally. Aerodynamic and acoustic measurements are conducted on a sawtooth-shaped trailing edge, retrofitted to a flat plate featuring a trailing-edge flap, and placed at incidence to the free-stream flow. The turbulent flow across the trailing edge is inspected by time-resolved three-dimensional velocity field measurements obtained from 4D-PIV, while the wall-pressure fluctuations are measured with surface-embedded microphones. Results discuss the relation between the velocity fluctuations over the serrations, the surface pressure fluctuations, and the far-field noise spectra. The aerodynamic analysis discusses the effect of counter-rotating vortex pairs, generated by the pressure imbalance across the edges of the serrations under loading. It is shown that the interaction of these vortices with the incoming turbulence affects the intensity of the wall-pressure spectrum at the outer rim of the serration surface. On the suction side, the intensity of the pressure fluctuations from the incoming boundary layer dominates over that induced by the vortex pairs. On the pressure side, instead, the velocity gradient prescribed by the vortex pairs produces a significant increase of the pressure fluctuations around the edges. The resulting spatial distribution of the wall-pressure fluctuations directly affects the far-field noise. Scattering predictions carried out with the wall-pressure fluctuations in the centre and root (on the suction side) exhibit good agreement with the measured noise in the low-frequency range, whereas using the surface pressure data at the tip of the serration (on the pressure side) yields a better prediction in the high-frequency range

Ochratoxigenic aspergillus in wine grapes and ochratoxin a in wines from Northeast Brazil.

Resumo

Otimização e validação de método para determinação de ácidos orgânicos em vinhos por cromatografia líquida de alta eficiência.

Reagentes e soluções analíticas; Instrumentação e condição cromatográfica; Estabilidade dos padrões analíticos e da fase móvel; Validação do método; Preparação das amostras de vinho

Chemical Potential and the Nature of the Dark Energy: The case of phantom

The influence of a possible non zero chemical potential $\mu$ on the nature of dark energy is investigated by assuming that the dark energy is a relativistic perfect simple fluid obeying the equation of state (EoS), $p=\omega \rho$ ($\omega <0, constant$). The entropy condition, $S \geq 0$, implies that the possible values of $\omega$ are heavily dependent on the magnitude, as well as on the sign of the chemical potential. For $\mu >0$, the $\omega$-parameter must be greater than -1 (vacuum is forbidden) while for $\mu < 0$ not only the vacuum but even a phantomlike behavior ($\omega <-1$) is allowed. In any case, the ratio between the chemical potential and temperature remains constant, that is, $\mu/T=\mu_0/T_0$. Assuming that the dark energy constituents have either a bosonic or fermionic nature, the general form of the spectrum is also proposed. For bosons $\mu$ is always negative and the extended Wien's law allows only a dark component with $\omega < -1/2$ which includes vacuum and the phantomlike cases. The same happens in the fermionic branch for $\mu 0$ are permmited only if $-1 < \omega < -1/2$. The thermodynamics and statistical arguments constrain the EoS parameter to be $\omega < -1/2$, a result surprisingly close to the maximal value required to accelerate a FRW type universe dominated by matter and dark energy ($\omega \lesssim -10/21$).Comment: 7 pages, 5 figure

Otimização e validação de método para determinação de ácidos orgânicos em vinhos por cromatografia líquida de alta eficiência.

The organic acids (tartaric, malic, citric, lactic and succinic) are de main components responsible for the acidity in the wine. This method for simultaneous determination of organic acids and interfering peaks in wines can be achieved in 16 min. The sample preceded by a dilution and filtration step. The chromatographic separation required one reversed phase column, isocratic mobile phase (acetonitrila, formic acid in water) and detection wavelength was set at 212 nm. The validation confirmed good repeatability, recovery and application in red and white wines.Nota técnica

Perfil agrossocioeconomico e estratos de produtividade da cultura do tomate na microbacia do Corrego da Cachoeira, Paty do Alferes, RJ.

A pesquisa foi conduzida na microbacia do Corrego da Cachoeira, municipio de Paty do Alferes (RJ), com os objetivos de realizar a caracterizacao do perfil agrossocioeconomico da area e estabelecer estratos de produtividade da cultura do tomate. A partir do levantamento de campo, obtiveram-se dados e informacoes de 42 produtores, sendo 27 categorizados como proprietarios e 15 como nao-proprietarios. O procedimento metodologico constou da utilizacao do Means e do metodo Average Linkage. A horticultura foi a principal atividade economica da microbacia, tendo tomate, pimentao, repolho, pepino, abobrinha e vagem como as especies mais cultivadas. O perfil tecnologico predominante caracterizou-se pelo uso indiscriminado de mecanizacao agricola, onde muitas vezes o preparo do solo e feito morro abaixo, pelo uso de adubacao e calagem, sem o devido acompanhamento de analise de solos; pela irrigacao feita diretamente nas covas, atraves de mangueiras, refletindo o que pode ser chamado de molhacao; e pelo uso generalizado de produtos fitossanitarios, praticamente sem orientacoes quanto as dosagens e frequencias de aplicacao. Os produtores de tomate foram estratificados em tres niveis, de acordo com a produtividade da referida cultura. Concluiu-se que, na area estudada, ha grande carencia de praticas conservacionistas, acompanhada de baixos niveis de organizacao sociocultural e de consciencia ambiental.bitstream/item/62849/1/CNPS-CIR.-TEC.-1-98.pdfConvenio Uniao Europeia/Brasil/Bolivia - Projeto DESUSMO

Anthocyanin composition of young red wine cv. Ruby Cabernet and Syrah: effect of time and storage conditions.

The aim of this study was to evaluate the evolution of anthocyanins in red wines for 12 months of storage in bottles in two different conditions. The wine samples cv. Ruby Cabernet and cv. Syrah (Vitis vinifera L.) used for this study were produced in the Sub-middle São Francisco Valley, in the Northeast Region of Brazil, during the 2013 harvest

Anthocyanin composition of young red wine cv. Ruby Cabernet and Syrah: effect of time and storage conditions.

The aim of this study was to evaluate the evolution of anthocyanins in red wines for 12 months of storage in bottles in two different conditions. The wine samples cv. Ruby Cabernet and cv. Syrah (Vitis vinifera L.) used for this study were produced in the Sub-middle São Francisco Valley, in the Northeast Region of Brazil, during the 2013 harvest

Teor relativo de clorofila em folhas de milho inoculado com Azospirillum braziliense sob diferentes doses de nitrogênio e manejo com braquiária.

A cultura do milho safrinha, implantada no início dos anos 80, no Estado do Paraná, ganhou destaque no fim dessa década como mais uma alternativa econômica na entressafra. Com objetivo de avaliar o teor relativo de clorofila em folhas de milho em função de doses de nitrogênio, inoculação das sementes e diferentes manejos, foi realizado um experimento de campo em Nitossolo Vermelho distroférrico, em Maringá (PR). Utilizaram-se três doses de nitrogênio (25, 50 e 75 kg ha-1), inoculante contendo estirpes de Azospirillum brasiliense no tratamento das sementes de milho e dois manejos distintos de milho solteiro e consorciado com Brachiaria ruziziensis. Os tratamentos foram arranjados com fatorial nas parcelas (doses de nitrogênio x presença e ausência de Azospirillum brasiliense) e em faixa nas subparcelas o milho safrinha (milho solteiro e consorciado com braquiária), sob o delineamento blocos ao acaso, com quatro repetições dos blocos, totalizando 64 parcelas. O teor relativo de clorofila nas folhas aumentou linearmente com as doses de nitrogênio utilizadas. Da mesma forma, as médias de todos os tratamentos que receberam a inoculação das sementes com Azospirillum brasiliense foram maiores que os tratamentos não inoculados. Por outro lado, o manejo não influenciou no teor relativo de clorofila nas folhas

Metabolic responses of guava trees irrigated with different N and K levels in São Francisco valley.

The guava (Psidium guajava 1.) cv. Paluma has been cultivated in Sao Francisco Valley, Northeastern of Brazil, for in natura consumption and processing purposes. In spite of its importance, there are few scientific knowledge regarding guava physiology, nutrition, irrigation and fertigation. The objective of this work was to evaluate the effect of weather conditions and different concentrations of Nand K applied by fertigation in foliar contents of reducing sugars, total soluble sugars, starch, sucrose, amino acids, and proteins. The field experiment was carried out at Bebedouro Experimental Field and the biochemical evaluations at the Laboratory of Seed and Plant Physiology, both located at Embrapa Semi-Arido, Petrolina-PE. The doses of200 g N and 100 g Kp; 400 g Nand 200 g O; 600 g Nand 300 g O; and 800 g Nand 400 g O per plant were applied in an experiment field. The experimental design was totally randomized blocks, with four treatments and five blocks. The weather conditions influenced the plant photosynthesis, which affects the plants metabolism. Guava presented specific responses to Nand K fertigation for each parameter evaluated. The weather conditions during the evaluation period influenced guava responses to N and K