Computational Fluid Dynamics Modeling of Ammonia Concentration in a Commercial Broiler Building

In the present study, a numerical model was developed to predict the flow pattern inside a broiler building. The model intends to predict the velocities fields inside the domain and am-monia (NH3) emitted or released by litter from poultry housing. The numerical model developed in Computational Fluid Dynamics (CFD) commercial code, intends to represent a commercial broiler building, and intends to simulate the 3D and heat transfer, in steady state flow. The evaporative cooling pads were also included in the model. The validation of the model was based in experimental measurements obtained in previous studies. The simulations were fo-cused on Summer, Winter and also Mid-Season situation. The numerical results of NH3 concen-tration were compared with the experimental measurements, and a quite good agreement was verified. The numerical results allowed the characterization of: the inside flow pattern devel-oped for the summer and winter situation; the inside NH3 distribution, and the velocity field distribution inside the broiler building. It was found that NH3 concentration increases along the tunnel, especially in low flow rate imposed from the exhaust fan. Also, it was verified that the low velocities inside domain are no sufficient to remove the gaseous pollutants.info:eu-repo/semantics/publishedVersio

The Possibility of Thermal Instability in Early-Type Stars Due to Alfven Waves

It was shown by dos Santos et al. the importance of Alfv\'en waves to explain the winds of Wolf-Rayet stars. We investigate here the possible importance of Alfv\'en waves in the creation of inhomogeneities in the winds of early-type stars. The observed infrared emission (at the base of the wind) of early-type stars is often larger than expected. The clumping explains this characteristic in the wind, increasing the mean density and hence the emission measure, making possible to understand the observed infrared, as well as the observed enhancement in the blue wing of the $H_\alpha$ line. In this study, we investigate the formation of these clumps a via thermal instability. The heat-loss function used, $H(T,n)$, includes physical processes such as: emission of (continuous and line) recombination radiation; resonance line emission excited by electron collisions; thermal bremsstrahlung; Compton heating and cooling; and damping of Alfv\'en waves. As a result of this heat-loss function we show the existence of two stable equilibrium regions. The stable equilibrium region at high temperature is the diffuse medium and at low temperature the clumps. Using this reasonable heat-loss function, we show that the two stable equilibrium regions can coexist over a narrow range of pressures describing the diffuse medium and the clumps.Comment: 21 pages (psfig.sty), 5 figures (included), ApJ accepted. Also available at http://www.iagusp.usp.br/preprints/preprint.htm

The role of damped Alfven waves on magnetospheric accretion models of young stars

We examine the role of Alfven wave damping in heating the plasma in the magnetic funnels of magnetospheric accretion models of young stars. We study four different damping mechanisms of the Alfven waves: nonlinear, turbulent, viscous-resistive and collisional. Two different possible origins for the Alfven waves are discussed: 1) Alfven waves generated at the surface of the star by the shock produced by the infalling matter; and 2) Alfven waves generated locally in the funnel by the Kelvin-Helmholtz instability. We find that, in general, the damping lengths are smaller than the tube length. Since thermal conduction in the tube is not efficient, Alfven waves generated only at the star's surface cannot heat the tube to the temperatures necessary to fit the observations. Only for very low frequency Alfven waves ~10^{-5} the ion cyclotron frequency, is the viscous-resistive damping length greater than the tube length. In this case, the Alfven waves produced at the surface of the star are able to heat the whole tube. Otherwise, local production of Alfven waves is required to explain the observations. The turbulence level is calculated for different frequencies for optically thin and thick media. We find that turbulent velocities varies greatly for different damping mechanisms, reaching \~100 km s^{-1} for the collisional damping of small frequency waves.Comment: 29 pages, 12 figures, to appear in The Astrophysical Journa

Spinning Relations: High-Speed Networks for Distributed Join Processing

By leveraging modern networking hardware (RDMA-enabled network cards), we can shift priorities in distributed database processing significantly. Complex and sophisticated mechanisms to avoid network traffic can be replaced by a scheme that takes advantag

Biomimetic amorphous titania nanoparticles as ultrasound responding agents to improve cavitation and ros production for sonodynamic therapy

Conventional therapies to treat cancer often exhibit low specificity, reducing the efficiency of the treatment and promoting strong side effects. To overcome these drawbacks, new ways to fight cancer cells have been developed so far focusing on nanosystems. Different action mechanisms to fight cancer cells have been explored using nanomaterials, being their remote activation one of the most promising. Photo-and sonodynamic therapies are relatively new approaches that emerged following this idea. These therapies are based on the ability of specific agents to generate highly cytotoxic reactive oxygen species (ROS) by external stimulation with light or ultrasounds (US), respectively. Crystalline (TiO2) and amorphous titania (a-TiO2) nanoparticles (NPs) present a set of very interesting characteristics, such as their photo-reactivity, photo stability, and effective bactericidal properties. Their production is inexpensive and easily scalable; they are reusable and demonstrated already to be nontoxic. Therefore, these NPs have been increasingly studied as promising photo-or sonosensitizers to be applied in photodynamic/sonodynamic therapies in the future. However, they suffer from poor colloidal stability in aqueous and biological relevant media. Therefore, various organic and polymer-based coatings have been proposed. In this work, the role of a-TiO2 based NPs synthesized through a novel, room-temperature, base-catalyzed, sol-gel protocol in the generation of ROS and as an enhancer of acoustic inertial cavitation was evaluated under ultrasound irradiation. A novel biomimetic coating based on double lipidic bilayer, self-assembled on the a-TiO2-propylamine NPs, is proposed to better stabilize them in water media. The obtained results show that the biomimetic a-TiO2-propylamine NPs are promising candidates to be US responding agents, since an improvement of the cavitation effect occurs in presence of the developed NPs. Further studies will show their efficacy against cancer cells

Composição bromatológica e cinética de fermentação ruminal de híbridos de sorgo com capim-sudão.

The objective of this study was to evaluate the nutritional value of 23 experimental genotypes and two control cultivars (AG2501C and BRS800) obtained by crossing sorghum with sudangrass (Sorghum bicolor cv. BicolorXSorghum bicolor cv. Sudanense), managed in a cutting regime. The bromatological analysis was performed, and the kinetics parameters of dry matter fermentation was obtained by the semi-automated in vitro gas production technique. A completely randomized block design was used for total gas production in a split plot arrangement. For all other responses an entirely randomized design was applied. The mean values were compared by Scott-Knott test. The genotypes CMSXS212*CMSXS912 and ATF14*CMSXS912 showed the highest dry matter content and the genotypes (A3TX430*CMSXS225)*CMSXS912, (A3TX430*CMSXS227)*CMSXS912, (BR007*CMSXS217)*CMSXS912, CMSXS210*CMSXS912, CMSXS157*CMSXS912, CMSXS215*CMSXS912, ATF14*CMSXS912, CMSXS205*CMSXS912, CMSXS156*CMSXS912, CMSXS107*CMSXS912, CMSXS216*CMSXS912 showed the highest protein level. The cell wall contents, the kinetics parameters and the effective dry matter degradation forb all the hybrids were not statistically different

Recuperação de áreas degradadas com base em sistema de produção florestal energético-madeireiro: indicadores de custos, produtividade e renda.

As áreas alteradas na Amazônia brasileira ocupam expressiva proporção do território. A reincorporação dessas áreas ao processo produtivo, a partir de plantações florestais, pode contribuir significativamente para o aumento da oferta de madeira de elevado valor econômico, e diminuir a pressão sobre as florestas nativas. A minimização de danos ambientais decorrentes de aumento na emissão de gases de efeito estufa; perdas de solo, água e nutrientes, além da biodiversidade que deve ser considerada. Para a pesquisa o desafio colocado é oferecer opções de sistemas agrícolas e florestais passíveis de utilização. E, além disso, é preciso que os sistemas de plantios florestais escolhidos, além de economicamente atrativos, sejam adequados à legislação ambiental em termos de manutenção de Áreas de Reserva Legal (ARL). Com a finalidade de contribuir para o fomento de plantios florestais na Amazônia, este trabalho tem por objetivo apresentar um modelo de produção florestal que combina as espécies castanha-do-pará ( Bertholletia excelsa H.B.K.); andiroba ( Carapa guianensis Aubl.), paricá ( Schizolobium amazonicum Huber) e taxi-branco (Sclerolobium paniculatum Vogel)