Eventos

Seminário DEM – Alexandros Terzis

Técnico - Campus Alameda

Terá lugar no próximo dia 20 de julho, às 10h00, o seminário “Heat release at the wetting front during capillary filling of cellulosic micro-substrates” proferido pelo Dr. Alexandros Terzis ( Institute of Aerospace Thermodynamics, ITLR, University of Stuttgart, Alemanha).

Resumo:
Spontaneous imbibition in cellulosic materials has an important applicability in paper-based microfluidics. This work uses simultaneous thermal and optical imaging to show that the temperature at the wetting front during capillary filling of paper is temporarily increased, even if the imbibed fluid and the cellulosic substrate are initially at isothermal conditions.
Different liquids are tested, together with two types of filter paper, which are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The results evidence a significant temperature rise at the wetting front that cannot be neglected form the process. This phenomenon is associated to the energetics of imbibition compounds, including acid-base contributions, that result in electrostatic attractions, as the liquid molecules are adhered on the fiber surfaces upon capillary contact.

Local: Sala de Reuniões do DEM, Pavilhão de Mecânica III.

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