11 research outputs found
DEVELOPMENT OF A NUMERICAL MODEL FOR THE STUDY OF AN OSCILLATING WATER COLUMN DEVICE CONSIDERING AN IMPULSE TURBINE
The present work brings a numerical study of an energy conversion device which takes energy from the waves through an oscillating water column (OWC), considering an impulse turbine with rotation in the chimney region through the implementation of a movable mesh model. More precisely, a turbulent, transient and incompressible air flow is numerically simulated in a two-dimensional domain, which mimics an OWC device chamber. The objectives are the verification of the numerical model with movable mesh of the impulse turbine in the free domain from the comparison with the literature and, later, the study of the impulse turbine inserted in the geometry of the OWC device. In order to perform the numerical simulation on the generated domains, the Finite Volume Method (FVM) is used to solve the mass and momentum conservation equations. For the closure of the turbulence, the URANS (Unsteady Reynolds Averaged Navier-Stokes) model k-ω SST is used. To verify the numerical model employed, drag coefficients, lift, torque and power are obtained and compared with studies in the literature. The simulations are performed considering a flow with a Reynolds number of ReD = 867,000, air as the working fluid and a tip speed ratio of λ = 2. For the verification case, coefficients similar to those previously predicted in the literature were obtained. For the case where the OWC device was inserted it was possible to observe an intensification of the field of velocities in the turbine region, which led to an augmentation in the magnitude of all coefficients investigated (drag, lift, torque and power). For the case studied with the tip velocity ratio λ = 2, results indicated that power coefficient was augmented, indicating that the insertion of the turbine in a closed enclosure can benefit the energy conversion in an OWC device
Pruning management of "Marselan" grapevines in the Serra do Sudeste region, in Southern Brazil.
The agronomical behavior of the ?Marselan? grapevine, indicated for the production of high-quality fine wines, is related to the management of the vineyard and the edaphoclimatic conditions of the cultivation region. This work aimed to evaluate the vegetative, productive, and qualitative behavior of ?Marselan? grapevines subjected to the Spur Pruning and Double Guyot pruning systems, cultivated in a municipality belonging to the Serra do Sudeste region, RS state, Brazil. The ?Marselan? grapevines were conducted in a vertical shoot positioning training system over a ?Paulsen 1103? rootstock, in a commercial vineyard located in Encruzilhada do Sul, RS, Brazil. During the 2016/2017 and 2017/2018 cropping seasons the vegetative vigor, the mass of pruned shoots, Ravaz Index, production, and chemical-physical composition of the must were evaluated. The double Guyot pruning system in the ?Marselan? grapevines induced a lower plant vigor, promoted an increase in the number of bunches per plant, bunch mass, production, and yield. The pruning type interferes with the vigor and yield of the ?Marselan? grapes without altering must quality. In the management of the cv. ?Marselan? in the Serra do Sudeste region, Brazil, the double Guyot pruning system is the most indicated
Effect of essential oils from Eucalyptus on the growth of aflatoxigenic species
In Brazil, Eucalyptus species has been cultivated as source of energy and cellulose. They represent the most important cultivated forest in the country. In production areas, the leaves from the trees decay on the soil as green fertilizer. In this study were evaluated pure and blends of essential oils from different species of eucalyptus trees grown in Brazil for antifungal activity against aflatoxigenic species Aspergillus flavus and A. parasiticus. These fungal species can grow and contaminate grains during the storage period under high r.h. conditions, with an eventual production of aflatoxins. Antifungal activity was evaluated by the radial growth measurement of the fungi inoculated on maize meal extract agar basic medium. The eucalyptus oils were evaluated in a contact assay and a fumigant assay using pure and blended oils. Six concentrations of pure and blended oils were evaluated at the following doses: 0, 2, 4, 16, 32 and 84 μL per 20 mL of fungi culture medium. Fungal inocula from conidia suspensions containing 106 spores/mL was inoculated by a needle. Glass Petri dishes were incubated for 9 days at 28°C (± 0.3°C) in the dark. Antifungal activity was observed in all pure and blended oils, in different concentrations of contact and fumigant assay, for both fungi. Eucalyptus stageiriana oil and E. stageiriana + the hybrid E. grandis x E. urophylla oils blend controlled the total fungal growth at the lowest dose (20 μL). Keywords: Essential oil; Eucalyptus spp.; Aspergillus flavus; Aspergillus parasiticus; Antifungal activity
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
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