Sök:

Sökresultat:

4 Uppsatser om Wetting - Sida 1 av 1

Computer Modelling of the Influence of Surface Topography on Water Repellency and a Study on Hydrophobic Paper Surfaces with Partly Controlled Roughness

A computer model based on minimization of the free energy, capable to predict contact angles and spreading transitions between Wenzel and Cassie mode for drops placed on surfaces with different topography were implemented in matlab. Simulations were compared with experiments documented in the literature. These showed that reported transitions between Cassie and Wenzel mode can be explained by minimization of the free energy. In this report, a study on the possibility of constructing water repellent paper surfaces with a combination of treatment with octadecyltrichlorosilane and topography changes, is included..

Frystorkning Kontrollerad torkning av kulturhistorisk dräkt?

Cultural objects may become wet by deliberate water cleaning, water disaster or watersoaked for other reasons. Air drying textile objects and even other organic materials from awater wet state, involves many problems depending on the strong capillarity action of water.Damages and changes such as bleeding of dyes, stains or lines of impurities from watermovement, shrinking or stiffness can occur. Freeze-drying as an alternative drying methodhas often been used for wet archaeological and marine objects, but more seldom for historicalmaterials.This bachelor thesis addresses the issue of whether freeze-drying can be an alternative controlleddrying method for historic costumes. Costumes and related objects are often compositeobjects, consisting of multiple materials, as well as being three dimensional, all of whichwill complicate drying. The purpose of this study was to investigate whether it is possible tohandle costume objects after wet cleaning for drying by freeze-drying, and if damages due tosurface tension of water, can be avoided in this way.

Fodrets inverkan på resultatet vid undersökning av förekomst av ockult blod i avföringen hos hund :

Hemoplus® (Sarstedt, Nümbrecht, Tyskland) is a guaiac-based fecal occult blood test developed for human medicine. Guaiac-based tests make use of the pseudoperoxidase activity of hemoglobin so the test is not specific for human hemoglobin and can therefore be used in veterinary medicine. Peroxidase-containing foods such as meat (hemoglobin and myoglobin) can cause false-positive results of the test. To ensure that a positive result is not caused by diet, it has been suggested that canine patients should be fed a meatless diet for a few days prior to fecal occult blood testing. The aim of this study was to evaluate the effect of commercial dog food on guaiac-based tests. In this study fecal samples from healthy dogs were analyzed with Hemoplus®.

Wicking ? Utvärdering av två standarder

Syftet med rapporten är att utvärdera och jämföra två standarder, AATCC Test method 198-2011: Horizontal Wicking of Textiles och AATCC Test method 197-2011: Vertical Wicking of Textiles. Standarderna publicerades år 2011 av American Association of Textile Chemists and Colorists. Standarderna mäter wicking, det vill säga, med vilken hastighet som vätska transporteras genom textil, med en horisontell och en vertikal testmetod. Hastigheten anges i olika enheter beroende på standard, enheten för AATCC Test method 197-2011: Vertical Wicking of Textiles är mm/s och AATCC Test method 198-2011: Horizontal Wicking of Textiles anges i mm2/s. Skillnaden i enhet och mätmetod innebär att standarderna inte kan jämföras rakt av genom resultat och mätvärden mellan de båda standarderna.