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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Determination of thermal transpiration effect for biomolecular gases with capacitance manometer

Johansson, Martin Viktor January 2015 (has links)
Capacitance manometer with sensors maintained at temperatures above the temperature of the vacuum vessel may read a higher gas pressure than the true value. This arises due to a transport process of molecules induced by molecule-surface collisions called thermal transpiration effect. Thermal transpiration effect depends on the pressure, the temperature gradient, gas, geometry and surface properties of the interconnecting pipe between the capacitance manometer and the vacuum vessel. To determine the height of the thermal transpiration effect for the biomolecular gas tetrahydrofuran, an experimental setup has been built. Its suitability to measure the thermal transpiration effect has been tested. Measurements of thermal transpiration effects for nitrogen and tetrahydrofuran have been analyzed with the semi-empirical Takaishi-Sensui equation. The coefficients of the Takaishi-Sensui equation can be used to determine the magnitude of the thermal transpiration effect for different temperature gradients, diameters of the interconnecting pipe and pressures.

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