Modelling liquid–liquid equilibria for island type ternary systems

Closed miscibility gaps in ternary liquid mixtures, at constant temperature and pressure, are obtained if phase separations occur only in the ternary region, whilst all binary mixtures involved in the system are completely miscible. This type of behaviour, although not very frequent, has been observed for a certain number of systems. Nevertheless, we have found no information about the applicability of the common activity coefficient models, as NRTL and UNIQUAC, for these types of ternary systems. Moreover, any of the island type systems published in the most common liquid–liquid equilibrium data collections, are correlated with any model. In this paper, the applicability of the NRTL equation to model the LLE of island type systems is assessed using topological concepts related to the Gibbs stability test. A first attempt to correlate experimental LLE data for two island type ternary systems is also presented.

On the existence of exponential polynomials with prefixed gaps

This paper shows that the conjecture of Lapidus and Van Frankenhuysen on the set of dimensions of fractality associated with a nonlattice fractal string is true in the important special case of a generic nonlattice self-similar string, but in general is false. The proof and the counterexample of this have been given by virtue of a result on exponential polynomials P(z), with real frequencies linearly independent over the rationals, that establishes a bound for the number of gaps of RP, the closure of the set of the real projections of its zeros, and the reason for which these gaps are produced.

Research gaps in accessibility and MOOCs: A systematic literature review 2008-2016 (dataset)

This study presents the results of a systematic literature review on the combined field of Accessibility and Massive Open Online Courses (MOOCs), covering the time period from 2008 to 2016.

Research gaps in accessibility and MOOCs: A systematic literature review 2008-2016 (dataset July 2016)

This study presents the results of a systematic literature review on the combined field of Accessibility and Massive Open Online Courses (MOOCs), covering the time period from 2008 to 2016 July. This dataset updates the previous release from 2008 to 2016 May (http://hdl.handle.net/10045/54846).