7,188 research outputs found
Direct numerical simulations of emulsion flows
In this paper, three-dimensional boundary integral computer simulations of emulsions in shear flows are described. Results for ordered BCC emulsions with dispersed-phase volume fractions below the critical concentration are presented. Complex rheological features including: shear-thinning viscosities, normal stress differences, and a nonlinear frequency response are also explored. For deformable drops, pair wise collision produces net cross-flow displacements that govern self-diffusion of drops. We compute trajectories of two interacting drops in shearing and present interesting numerical simulations of three dimensional gravity-induced motion of two drops. The results also demonstrate the feasibility of simulating high-volume-fraction emulsions and foam
Effect of the type of emulsifying salt on microstructure and rheological properties of "requeijão cremoso" processed cheese spreads.
The role of different types of emulsifying salts-sodium citrate (TSC), sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP) and tetrasodium pyrophosphate (TSPP)-on microstructure and rheology of "requeijão cremoso" processed cheese was determined. The cheeses manufactured with TSC, TSPP, and STPP behaved like concentrated solutions, while the cheese manufactured with SHMP exhibited weak gel behavior and the lowest values for the phase angle (G"/G'). This means that SHMP cheese had the protein network with the largest amount of molecular interactions, which can be explained by its highest degree of fat emulsification. Rotational viscometry indicated that all the spreadable cheeses behaved like pseudoplastic fluids. The cheeses made with SHMP and TSPP presented low values for the flow behavior index, meaning that viscosity was more dependent on shear rate. Regarding the consistency index, TSPP cheese showed the highest value, which could be attributed to the combined effect of its high pH and homogeneous fat particle size distribution
Cancellation of atmospheric turbulence effects in entangled two-photon beams
Turbulent airflow in the atmosphere and the resulting random fluctuations in
its refractive index have long been known as a major cause of image
deterioration in astronomical imaging and figures among the obstacles for
reliable optical communication when information is encoded in the spatial
profile of a laser beam. Here we show that using correlation imaging and a
suitably prepared source of photon pairs, the most severe of the disturbances
inflicted on the beam by turbulence can be cancelled out. Other than a
two-photon light source, only linear passive optical elements are needed and,
as opposed to adaptive optics techniques, our scheme does not rely on active
wavefront correction.Comment: 5 pages, 3 figure
Reflectance of Polytetrafluoroethylene (PTFE) for Xenon Scintillation Light
Gaseous and liquid xenon particle detectors are being used in a number of
applications including dark matter search and neutrino-less double beta decay
experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors
both as electrical insulator and as a light reflector to improve the efficiency
of detection of scintillation photons. However, xenon emits in the vacuum
ultraviolet wavelength region (175 nm) where the reflecting properties of PTFE
are not sufficiently known.
In this work we report on measurements of PTFE reflectance, including its
angular distribution, for the xenon scintillation light. Various samples of
PTFE, manufactured by different processes (extruded, expanded, skived and
pressed) have been studied. The data were interpreted with a physical model
comprising both specular and diffuse reflections. The reflectance obtained for
these samples ranges from about 47% to 66% for VUV light. Fluoropolymers,
namely ETFE, FEP and PFA were also measured
Metodologia para a Geração de Mosaicos Semicontrolados a partir de Imagens Orbitais Provenientes do Google Earth.
bitstream/item/125513/1/Comunicado-309.pd
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