Search results for "Thermodiffusion"
showing 3 items of 3 documents
Fernand de Montessus de Ballore, à la naissance de la sismologie moderne
2012
Fernand de Montessus de Ballore (1851-1923) est considéré comme un des précurseurs de la sismologie moderne. On lui doit une importante production scientifique dans ce domaine : il a notamment établi, par des relevés rigoureux et nombreux, que les tremblements de terre étaient en relation avec la géologie et non avec les phases de la lune ou les volcans souterrains comme on le supposait au début du XXe siècle. Officier de l'armée française, alors en garnison à Nîmes, il écrit en 1886 au scientifique genevois Louis Soret (1827-1890), qui fait partie de la commission suisse chargée d'étudier les séismes dans ce pays. C'est l'analyse de cette lettre à Soret qui fait l'objet de notre article.
Thermodiffusion of sodium polystyrene sulfonate in a supporting electrolyte
2019
Thermodiffusion, or the Soret phenomenon, is well understood in simple systems, but in multicomponent and polyvalent electrolyte systems the process becomes more complicated due to the coupling of fluxes. We experimentally investigate the time evolution of a concentration gradient generated by thermodiffusion of a polyelectrolyte (poly(sodium 4-styrene sulfonate), NaPSS) in a 1:1 supporting electrolyte. We also derive and solve the transport equations that are used to extract the Soret coefficient from the experimental observations. It is shown that NaPSS thermodiffusion in NaCl is strongly dependent on concentration, with almost 100% thermal separation in concentrations below 15 nmol L−1. …
Soret coefficient of trace ions determined with electrochemical impedance spectroscopy in a thin cell. Theory and measurement
2018
The tendency of a substance to migrate due to a temperature gradient is known as thermodiffusion or the Soret effect. We believe that this is the first work that describes the study of the Soret effect using electrochemical impedance spectroscopy in a non-isothermal thin cell, and shows how the Soret coefficient can be determined from these measurements. The effect of a temperature gradient in a thin cell is analyzed, both theoretically and experimentally. Our theoretical modeling of the system predicts the effect of key parameters to the impedance spectra. Experimentally we determine the Soret coefficient of the redox couple Fe(CN)64−/Fe(CN)63− in an aqueous KCl solution. It is found that …