885 research outputs found
Porous 'Ouzo-effect' silica-ceria composite colloids and their application to aluminium corrosion protection.
By exploiting spontaneous emulsification to prepare porous SiO(2) particles, we report the formation of porous CeO(2)@SiO(2) hybrid colloids and their incorporation into a silica-zirconia coating to improve the corrosion protection of aluminium
THE VALUE OF ECOLOGICAL AND ECONOMIC INFORMATION IN WATER QUALITY MANAGEMENT
Replaced with revised version of paper 08/25/03.Environmental Economics and Policy,
Influence of phase composition on Portevin-Le Chatelier effect in Al-Mg alloys
The temperature-strain rate domain of the Portevin-Le Chatelier (PLC) effect has been determined for three ultrafine grained aluminum alloys: Al-3Mg (А1), Al-4,57Mg0,35Mn-0,2Sc-0,09Zr (А2) and Al-5,4Mg-0,52Mn-0,1Zr (А3) (wt.%). The apparent activation energy of the serrated yielding was estimated. It was found that the presence of dispersed particles leads to a decrease in the activation energy and the temperature–strain rate domain of the PLC effect becomes narrowe
Irregular HF radio propagation on a subauroral path during magnetospheric substorms
The impact of the main ionospheric trough, sporadic structures, gradients and inhomogeneities of the subpolar ionosphere during substorms on the signal amplitude, azimuthal angles of arrival, and propagation modes for the radio path Ottawa (Canada)-St. Petersburg (Russia) was considered. This subauroral path with the length of about 6600 km has approximately an east-west orientation. The main goals are to carry out numerical modeling of radio propagation for the path and to compare the model calculations with experimental results. Wave absorption and effects of focusing and divergence of rays were taken into consideration in the radio wave modeling process. The following basic results were obtained: The signal amplitude increases by 20–30 dB 1–1.5 h before the substorm expansion phase onset. At the same time the signal azimuth deviates towards north of the great circle arc for the propagation path. Compared with quiet periods there are effects due to irregularities and gradients in the area of the polar edge of the main ionospheric trough on the passing signals. Propagation mechanisms also change during substorms. The growth of signal amplitude before the substorm can be physically explained by both a decrease of the F2-layer ionization and a growth of the F2-layer height that leads to a decrease of the signal field divergence and to a drop of the collision frequency. Ionospheric gradients are also important. This increase of signal level prior to a substorm could be used for forecasting of space weather disturbed conditions
The dynamic recrystallization behavior in Al-Mg alloys
The influence of phase composition on the behavior of dynamic recrystallization in alloys Al-3Mg (А1), Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (А2) and Al-5.4Mg-0.52Mn-0.1Zr (А3) (wt.%) during the equal-channel angular pressing (ECAP) was studied. The ECAP processing of alloy A1 resulted in a partially recrystallized microstructure with the mean size of coarse and fine grains of 20 and 1.4 μm, respectively In contrast, the formation of fully-recrystallized microstructure was observed in the alloys A2 and A
A Spatial Analysis of Obesity in West Virginia
A spatial panel data analysis at the county level examines how individual food consumption, recreational, and lifestyle choices ― against a backdrop of changing demographic, built environment, and policy factors ― leads to obesity. Results suggest that obesity tends to be spatially autocorrelated; in addition to hereditary factors and lifestyle choices, it is also caused by sprawl and lack of land use planning. Policy measures which stimulate educational attainment, poverty alleviation, and promotion of better land use planning and best consumption practices (BCPs) could both reduce obesity and result in sustainable development of regions where obesity is prevalent and the economy is lagging
The Impact of County Level Factors on Obesity in West Virginia
A panel estimation of county prevalence of obesity indicates that while the percentage of the population with a completed college degree and the number of food stores available per thousand population are negatively and significantly correlated to county obesity rates, mean commuting time, average annual wage and the total number of business establishments per thousand population positively and significantly contribute to obesity. Educational attainment that raises both human and social capital, as well as changes in the built environment can play a vital role in controlling obesity in West Virginia (WV)
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