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Browsing DCA - Parte ou Capítulo de um Livro / Part of Book or Chapter of Book by Subject "Alkali Metal Vapours"
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- Reacting Mixtures at Low Density - Alkali Metal VapoursPublication . Fialho, Paulo; Ramires, Maria de Lurdes V.; Nieto de Castro, Carlos A.; Fareleira, João M.N.A."Previous chapters of this volume dealt with the transport properties of nonreacting mixtures. However, there are several systems of scientific and industrial interest that involve chemical reactions between some of the atoms or molecules present. This fact modifies the values of the transport properties of these systems because there are additional processes of heat and mass transfer caused by the existence of the chemical reaction. The simplest kind of system where chemical reaction is present is an alkali metal vapour, where dimerization of atoms takes place, with a temperature- and pressuredependent composition. This fact, allied to the high-temperature domain of the application of these vapors, makes the determination of the transport properties of these systems very challenging from a theoretical point of view. […]".
- Viscosity, Thermal Conductivity and Thermal Diffusion Ratio of the Alkali Metal Vapours.Publication . Fialho, Paulo; Ramires, Maria de Lurdes V.; Fareleira, João M.N.A.; Nieto de Castro, Carlos A.The Subcommittee of Transport Properties of IUP AC started in 1982 a project with the objective of correlating and predicting the transport properties of the alkali metal vapours, in the temperature and pressure zones that are useful to the scientific and industrial uses. In a recent paper [1] the authors suggested a new approach to assess the available experimental data, based in the kinetic theory of gas mixtures, which is a modification of the method developed by Vargaftik and Yargin[2]. In the present communication, we present the surfaces for the viscosity and thermal conductivity, and thermal diffusion ratio which have been developed for lithium, sodium and potassium with average uncertainties of 1%, 0.5% and 0.5%, respectively, for temperature ranges 800-2000 K (lithium) and 700-1500 K (sodium and potassium). . For rubidium and cesium, the available data does not allow a similar development of the corresponding surfaces. It is interesting to note that no clear evidence for the presence of dimers was found for cesium within experimental uncertainty.