Surface tension measurements of viscous materials by pendant drop method: time needed to establish equilibrium shape

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389013%3A_____%2F19%3A00504710" target="_blank" >RIV/61389013:_____/19:00504710 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Surface tension measurements of viscous materials by pendant drop method: time needed to establish equilibrium shape

Popis výsledku v původním jazyce

The pendant drop method of surface tension measurements published in 1938 has been frequently used since late 1960s. The time to reach equilibrium drop shape for viscous materials was mentioned in few papers only. The aim of this paper is to estimate time needed to reach a shape sufficiently close to equilibrium as a function of required precision and material viscosity. The procedure is based on Roe's error analysis of the pendant drop method and on a prerequisite of similarity in relaxation times of pendant drop and that of ellipsoid droplet published by Luciani and Utracki. An equation for time needed to reach equilibrium shape of pendant drop has been derived. Estimates have been verified through measurements of a test liquid, strong correction using empirical coefficients is needed to predict equilibration times correctly. The formula found is useful to assess whether the measurement can be accomplished before the material starts to degrade or otherwise change significantly. Since approximation using formula for ellipsoid relaxation is a weak point of the estimate, the challenge remaining for future is to describe the relaxation of pendant drop.

Název v anglickém jazyce

Surface tension measurements of viscous materials by pendant drop method: time needed to establish equilibrium shape

Popis výsledku anglicky

The pendant drop method of surface tension measurements published in 1938 has been frequently used since late 1960s. The time to reach equilibrium drop shape for viscous materials was mentioned in few papers only. The aim of this paper is to estimate time needed to reach a shape sufficiently close to equilibrium as a function of required precision and material viscosity. The procedure is based on Roe's error analysis of the pendant drop method and on a prerequisite of similarity in relaxation times of pendant drop and that of ellipsoid droplet published by Luciani and Utracki. An equation for time needed to reach equilibrium shape of pendant drop has been derived. Estimates have been verified through measurements of a test liquid, strong correction using empirical coefficients is needed to predict equilibration times correctly. The formula found is useful to assess whether the measurement can be accomplished before the material starts to degrade or otherwise change significantly. Since approximation using formula for ellipsoid relaxation is a weak point of the estimate, the challenge remaining for future is to describe the relaxation of pendant drop.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10404 - Polymer science

Projekt

<a href="/cs/project/LO1507" target="_blank" >LO1507: Polymery pro pokročilé technologie i kvalitnější život</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů