Thermal Conductivity of Ionic Liquids and IoNanofluids. Can Molecular Theory Help?

Ionic liquids have been suggested as new engineering fluids, specifically in the area of heat transfer, and as alternatives to current biphenyl and diphenyl oxide, alkylated aromatics and dimethyl polysiloxane oils, which degrade above 200 °C, posing some environmental problems. Addition of nanoparticles to produce stable dispersions/gels of ionic liquids has proved to increase the thermal conductivity of the base ionic liquid, potentially contributing to better efficiency of heat transfer fluids. It is the purpose of this paper to analyze the prediction and estimation of the thermal conductivity of ionic liquids and IoNanofluids as a function of temperature, using the molecular theory of Bridgman and estimation methods previously developed for the base fluid. In addition, we consider methods that emphasize the importance of the interfacial area IL-NM in modelling the thermal conductivity enhancement. Results obtained show that it is not currently possible to predict or estimate the thermal conductivity of ionic liquids with an uncertainty commensurate with the best experimental values. The models of Maxwell and Hamilton are not capable of estimating the thermal conductivity enhancement of IoNanofluids, and it is clear that the Murshed, Leong and Yang model is not practical, if no additional information, either using imaging techniques at nanoscale or molecular dynamics simulations, is available.

Professorship and family life

Chapter 2 describes Lorentz’s appointment as university professor, his move from Arnhem to Leiden, the methodology and views on physics in his inaugural lecture on molecular theories in physics, and his use of mathematics for the development of his theoretical work on optics and molecular theory, among other topics. Lorentz’s induction and involvement in the Royal Academy of Sciences is discussed in this chapter. Other sections are devoted to Lorentz’s experimental work in physics together with Pieter Zeeman, and to his work with various friends and colleagues, like Kamerlingh Onnes and Van de Sande Bakhuyzen. Lorentz’s first foreign contacts are explored, in particular those with Woldemar Voigt, Ludwig Boltzmann, Felix Klein, and Walther Nernst. Lorentz’s teaching and his first public activities are discussed here, as well as his marriage and his family life.

Understanding of Kinetic Molecular Theory of Gases in Three Modes of Representation among Tenth-Grade Students in Chemistry

An analysis of students’ performance in Kinetic Molecular Theory (KMT) of gases was done to determine the extent of the understanding of these chemistry concepts in three modes of representation, namely macroscopic, microscopic, and symbolic. The study employed one-shot quasi-experimental research where students in Grade 10 at a secondary school in Cebu City were exposed to the Integrated Macro-Micro-Symbolic Approach (IMMSA). A validated post-test tool with macro, micro, and symbolic questions was used in the study. The post-test results revealed that there was a gradual improvement of the students’ understanding from a good understanding of macroscopic and microscopic levels to a very good understanding of the symbolic level. Thus, it was concluded that the use of three modes of chemical representation led to a high extent in the understanding of concepts in chemistry. It is recommended that teachers begin their instruction at the macroscopic level and introduce symbols only after the microscopic level.