A two-phase flow approach to cavitation modelling in journal bearings

Cavitation has been extensively treated in numerical models for lubrication using boundary conditions in the pressure equation, and several criteria are available. However, an inappropriate choice can lead to imprecise results, thus having serious implications for performance prediction. This work proposes the numerical solution for lubrication analysing the changes suffered by the lubricant along a journal bearing, considering the release of gas from the liquid and the existence of a two-phase flow. Results obtained are compared with those using the Reynolds, or Swift-Steiber, boundary condition. The influence of fluid properties on the main parameters of bearing operation is also discussed.     

Eco-efficiency and techno-economic analysis for maleic anhydride manufacturing processes

Clean Technologies and Environmental Policy - Maleic anhydride may be obtained from different technological routes, being the selective oxidation of benzene and oxidation of butane the only ones...     

Computer vision for improved estimates of SO2 emission rates and plume dynamics

Imaging cameras operating at ultraviolet (UV) and infrared (IR) wavelengths can measure sulphur dioxide (SO₂) gas path concentrations or slant column densities. These measurements are useful in a variety of applications including the monitoring of emissions from volcanoes and also emissions from stacks at industrial plants and on ships. The usefulness of these data is increased if the emission rates (or fluxes) of the gases can also be estimated. Here we present an optical flow algorithm that allows rapid and accurate estimates of emission rates using both UV and IR camera imagery sampling at around 1 Hz or higher. Examples are provided from measurements made at Turrialba volcano, Costa Rica, and also at a ship in Hong Kong harbour. Other aspects of the properties of the fluid flow are also introduced, notably the divergence and the vorticity of the two-dimensional wind field. We demonstrate how the divergence can be used in a new method to calculate the emission rate and show how rotational effects observed in volcanic plumes and the resulting entrainment of ambient air affects plume rise and can be observed using vorticity. This is an important aspect for understanding the emplacement of gases and particles into the atmosphere that are subsequently transported by atmospheric winds, sometimes causing pollution episodes at long distances from the source.     

Influence of the Oil Phase on the Microencapsulation by Complex Coacervation

The influence of oil type on the process yield, efficiency of encapsulation, particle size and morphological aspects of coacervated microparticles was investigated. Firstly, several factors affecting microencapsulation of oils by complex coacervation were simultaneously examined. The results indicated that the process yield is mainly dependent on the velocity of homogenization, temperature and polymer ratio. Using optimum conditions for producing microparticles [pH 4.0, 14,000 rpm, 50 °C, gelatin:gum arabic (GE:GA) 1:1 and 2.5 % w/v], different core materials were tested: a vegetable oil (almond oil), an oil with higher hydrophilic lipophilic balance (vetiver essential oil) and a highly hydrophobic oil (mineral oil). The oil phase exerted an influence on microparticle formation, disturbing the complexation of polymers and modifying the core distribution within the particles. Some of the polymers were complexed when mineral oil was used, and the highest efficiency of encapsulation (91.8 %) was obtained with vetiver oil, followed by the almond (70.6 %) and mineral (38.0 %) oils. Particles produced with vetiver oil were larger (43.5 μm) than those produced with mineral oil (35.0 μm) and almond oil (19.2 μm), and the increase in the size is due to the encapsulation of many small droplets of emulsion, characterizing these particles as multinucleate ones.     

Evaporation of volatile liquids from an open-topped,partially filled container to an air stream

Experiments were performed to measure the evaporative mass transfer from a partially filled, slot-like container recessed in the floor of a flat rectangular duct through which turbulent air flow was passed. Toluene and cumene were used as the evaporating liquids, and systematic variations were made of the Reynolds number and of the distance between the top of the container and the surface of the evaporating liquid. The measured Sherwood numbers displayed unconventional dependences on both the Reynolds and Schmidt numbers as well as a complex dependence on the top-to-surface distance.     

A resistive sheet approximation for mesh reflector antennas

A simplified method of estimating the equivalent surface resistance of a reflecting mesh is presented. The equivalent resistance is obtained from the approximate mesh reflection coefficients, which are based on averaged boundary conditions. This resistance approximation allows an integral equation solution for the mesh reflector that is a simple extension of that for the perfectly conducting reflector. Paraboloid radiation patterns using physical optics in conjunction with the reflection coefficients are compared to an E-field integral equation solution for a resistive surface. The agreement is excellent for low to moderate resistance values, even in the sidelobe regions     

The along track scanning radiometer for ERS-1-scan geometry anddata simulation

The first European remote-sensing satellite (ERS-1) will carry the along track scanning radiometer (ATSR). which has been specifically designed to give accurate satellite measurements of sea surface temperature (SST). Details of the novel scanning technique used by the ATSR are given, and data from the NOAA-9 AVHRR instrument are used to simulate raw ATSR imagery. Because of the high precision of the onboard blackbodies, the active cooling of the detectors, 12-b digitization, and dual-angle capability, the ATSR promises to achieve higher-accuracy satellite-derived SSTs than are currently available     

In Vitro and In Vivo Behaviour of In Complexes of TTHA, TTHA-Bis(Butylamide) and TTHA-Bis(Glucamide): Stability, Biodistribution and Excretion Studied by Gamma Imaging

Aiming at radiopharmaceutical application, (111)In(3+) complexes of the polyaminocarboxylates TTHA, TTHA-bis(butylamide) and TTHA-bis(glucamide) were investigated. The in vitro stability of (111)In(TTHA)(3-) and (111)In(TTHA-bis(butylamide)(-) was evaluated by measuring the exchange of (111)In(3+) from the complexes to transferrin and the results were compared with those for (111)In(DTPA)(2-). We also performed biodistribution studies of the three (111)In(3+) complexes by gamma-imaging in Wistar rats and by measuring the radioactivity in their organs. TTHA and its derivatives seem to have similar in vivo biodistribution with prevailing renal excretion.