2,999 research outputs found

    3D-PTV of particle-laden turbulent pipe flows

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    Turbulent dispersed two-phase flows are ubiquitous in both industry and nature. Flows of this kind are characterized by particles, droplets or bubbles dispersed within a carrier phase. Predicting the behavior of this kind of flows is therefore of quite some interest in engineering applications. However, due to the complex nature of the problem, the available models are usually simplified and not able to fully predict fluid and particle behavior for the whole range of applications. Experiments are indispensable tools to understand the underlying physics of dispersed two-phase flows. Experiments therefore serve to improve the efficiency and reliability of numerical or theoretical models. However, the lack of consistent experimental data makes validation of existent models difficult. Among the numerous turbulent dispersed two-phase flows, a particular class possesses challengeable and interesting properties that need disclosure: flows where the dispersed phase is able to interact with turbulent eddies. This class of dispersed two-phase flows is even more interesting and of practical importance in an inhomogeneous turbulent velocity field such as found in pipes. This work aims at experimental clarification of the essential physics of turbulent particle-laden pipe flows with a characteristic ratio of turbulent carrier-phase RMS velocity and terminal velocity of inertia particles, urms/UTV, of order one. An experimental setup is arranged in such way that the liquid and particle three-dimensional velocities in upward and downward vertical flows can be measured. The optical technique three-dimensional particle tracking velocimetry (3D-PTV) is applied to gather Lagrangian and Eulerian statistics for both flow tracers and inertia particles. To the best of our knowledge, no Lagrangian results have been reported for particle-laden pipe flows. The role of inertia, flow turbulence and flow orientation with respect to gravity on concentration profile and mean relative velocity of particle-laden pipe flows is presented. The effect of particle feedback on the fluid is presented with d-forcing. The relevance of the break-up mechanism in the transport of inertia particles in transient pipe flows is discussed. The main features of Lagrangian velocity and acceleration statistics of flow tracers and inertia particles are disclosed

    Qualidade Físico-química E Sensorial De Genótipos De Banana

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    Despite the diversity of banana varieties in Brazil, only a few cultivars have the proper agronomic traits and fruit quality for commercial exploitation. This study aimed at evaluating the physicochemical traits and sensorial acceptance of banana genotypes, in order to identify those with potential for commercial growing. Six improved banana genotypes were assessed (BRS Maravilha, PC 0101, FHIA 18, TM 2803, YB 4203 and BRS Caipira), as well as three commercial cultivars (Grand Naine, Pacovan and Prata Anã). Analyses of peel and pulp color, peel thickness, pulp yield, moisture, pH, soluble solids, titratable acidity, total carotenoids and sensorial acceptance were performed. The BRS Maravilha, FHIA 18, YB 4203 and BRS Caipira genotypes presented physicochemical traits similar to the Grand Naine, Pacovan and Prata Anã commercial cultivars. The BRS Maravilha and TM 2803 genotypes had sensorial acceptance similar to the Prata Anã and Grand Naine cultivars, and are therefore promising for commercial growing, with the advantage of being resistant to the black Sigatoka and Panama disease. © 2016, Universidade Federal De Goias (UFG). All Rights Reserved.461899

    Gathering and managing complementary diagnostic tests

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    Personal health information is constituted in its greatest part by complementary diagnostic tests which are an important medical aid. This information is generated dispersedly because the patient seeks medical care in many different places over his lifetime. Access to a comprehensive set of a patient’s health information is a challenge. It revolves around the patient so any managing scheme must be patient-centric. We took a pragmatic approach to this problem and developed a software standalone platform for secure personal health information storage, namely complementary diagnostic tests, on a portable device for mobility. Simplicity and ease of use were main objectives. A special attention was given to the security aspects associated with storing this kind of information

    Evaluation of Antioxidant Parameters in Rats Treated with Sevoflurane

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    SummaryBackground and objectivesSevoflurane is a halogenated fluorinated ether that undergoes hepatic biotransformation through cytochrome P4502E1. Halogenated ethers undergoing biotransformation by P4502E1 can produce reactive oxygen species (ROS), weakening the antioxidant defense mechanism. The objective of this study was to investigate the relationship between the activity of erythrocyte antioxidant enzymes and sevoflurane.MethodsAnimals were divided in four groups: Group 1 – control: 100% oxygen (1 L.min-1 for 60 min during five consecutive days); Group 2 – 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five consecutive days); Group 3 – isoniazid (i.p.), 50 mg.kg-1/day for four consecutive days, followed by 100% oxygen (1 L.min-1 for 60 minutes during four consecutive days); Group 4 – intraperitoneal isoniazid, 50 mg.kg-1 daily for four days, followed by 4.0% sevoflurane in 100% oxygen (1 L.min-1 for 60 minutes during five days). Twelve hours after the last exposure to sevoflurane, animals were sacrificed and their blood was collected through the portal vein for analysis of antioxidant enzymes.ResultsAn increase in the activity of glucose-6-phosphate dehydrogenase and a decrease in the activity of catalase were observed, especially in the group of animals pre-treated with isoniazid. Changes in the activity of glutathione peroxidase were not observed.ConclusionsThe interaction between sevoflurane and cytochrome P450 2E1 with enzymatic inducers can lead to oxidative stress with prolonged and repetitive exposure

    Existence of weak solutions for the generalized Navier-Stokes equations with damping

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    In this work we consider the generalized Navier-Stokes equations with the presence of a damping term in the momentum equation. The problem studied here derives from the set of equations which govern isothermal flows of incompressible and homogeneous non-Newtonian fluids. For the generalized Navier-Stokes problem with damping, we prove the existence of weak solutions by using regularization techniques, the theory of monotone operators and compactness arguments together with the local decomposition of the pressure and the Lipschitz-truncation method. The existence result proved here holds for any and any sigma > 1, where q is the exponent of the diffusion term and sigma is the exponent which characterizes the damping term.MCTES, Portugal [SFRH/BSAB/1058/2010]; FCT, Portugal [PTDC/MAT/110613/2010]info:eu-repo/semantics/publishedVersio

    Integral field spectroscopy of massive young stellar objects in the N113 H II region in the Large Magellanic Cloud

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    The Spitzer Surveying the Agents of Galaxy Evolution (SAGE) survey has allowed the identification and analysis of significant samples of Young Stellar Object (YSO) candidates in the Large Magellanic Cloud (LMC). However, the angular resolution of Spitzer is relatively poor meaning that at the distance of the LMC, it is likely that many of the Spitzer YSO candidates in fact contain multiple components. We present high-resolution K-band integral field spectroscopic observations of the three most prominent massive YSO candidates in the N113 H?II region using Very Large Telescope/Spectrograph for INtegral Field Observations in the Near Infrared (VLT/SINFONI). We have identified six K-band continuum sources within the three Spitzer sources and we have mapped the morphology and velocity fields of extended line emission around these sources. Br ?, He?I and H2 emission is found at the position of all six K-band sources; we discuss whether the emission is associated with the continuum sources or whether it is ambient emission. H2 emission appears to be mostly ambient emission and no evidence of CO emission arising in the discs of YSOs has been found. We have mapped the centroid velocities of extended Br ? emission and He?I emission and found evidence of two expanding compact H?II regions. One source shows compact and strong H2 emission suggestive of a molecular outflow. The diversity of spectroscopic properties observed is interpreted in the context of a range of evolutionary stages associated with massive star formation

    Strong and auxiliary forms of the semi-Lagrangian method for incompressible flows

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    We present a review of the semi-Lagrangian method for advection-diusion and incompressible Navier-Stokes equations discretized with high-order methods. In particular, we compare the strong form where the departure points are computed directly via backwards integration with the auxiliary form where an auxiliary advection equation is solved instead; the latter is also referred to as Operator Integration Factor Splitting (OIFS) scheme. For intermediate size of time steps the auxiliary form is preferrable but for large time steps only the strong form is stable
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