Search for dissertations about: "hydrogen and oxygen diffusion"

Showing result 1 - 5 of 38 swedish dissertations containing the words hydrogen and oxygen diffusion.

2. 1. Modified oxygen and hydrogen transport in Zr-based oxides

   Author : Clara Anghel; Gunnar Hultquist; Magnus Limbäck; Truls Norby; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Zirconia; Zirconium; Zircaloy; hydrogen and oxygen diffusion; SPP; oxygen dissociating elements; oxidation; dissociation; hydration; CO adsorption; molecular transport; porosity.; Materials science; Teknisk materialvetenskap;

   Abstract : Most metals and alloys in the presence of oxygen and moisture will instantaneously react and form a thin (2-5 nm) surface oxide layer. For further reaction to occur, oxygen ions and/or metal cations often diffuse through the already formed oxide layer. READ MORE

4. 2. Alternative methods for analysing moisture transport in buildings : Utilisation of tracer gas and natural stable isotopes

   Author : Kjartan Gudmundsson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; tracer gas; water vapour permeability; diffusion; surface diffusion; isotopic analysis; deuterium; oxygen-18; fractionation; vapour barrier; transient numerical modelling of diffusion; Building engineering; Byggnadsteknik;

   Abstract : New methods, based on tracer gas measurements and isotopicanalysis can be used to evaluate the moisture properties ofbuilding materials and provide the means for forensic analysisof the origins and history of excessive water in buildings, theimmediate practical consequences of which will be the abilityto improve the moisture performance of constructions. It is shown, in theory and through measurements how thewater vapour permeability of porous building materials can witha good degree of accuracy be estimated with tracer gasmeasurements that provide an efficient alternative to the cupmethod. READ MORE

5. 3. Nitrogen and Water in High Temperature Corrosion - Insights from First Principle Calculations

   Author : Vedad Babic; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; DFT; alumina; nitridation; corrosion; chromia; hydrogen;

   Abstract : Service life-time of alloys used in high temperature applications is often limited by corrosion. FeCrAl(Re) alloys are partially designed to form a protective α-alumina oxide scale at elevated  temperatures in order to mitigate further oxidation. READ MORE

6. 4. Escape to space or return to venus : ion flows measured by venus express

   Author : Moa Persson; Yoshifumi Futaana; Hans Nilsson; Maria Hamrin; Dmitrij Titov; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Venus; water; escape; planetary physics; oxygen; O ; hydrogen; H ; ions; space physics; space plasma physics; Venus Express; ASPERA-4; IMA; spacecraft measurements; rymd- och plasmafysik; Space and Plasma Physics;

   Abstract : The present-day Venusian atmosphere is crushingly dense, extremely hot and arid. Yet, in its early history, Venus presumably had a massive amount of water, which, if spread evenly over the surface, provided a water depth of 10s to 100s of meters. Therefore, over the course of the atmospheric evolution, the water must have been removed from Venus. READ MORE

7. 5. Studies of transport in oxides on Zr-based materials

   Author : Clara Anghel; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Zirconium; hydrogen; oxygen diffusion; second-phase particle; oxidation; dissociation; hydration; carbon monoxide; adsorption; porosity; Other materials science; Övrig teknisk materialvetenskap;

   Abstract : Zr-based materials have found their main application in the nuclear field having high corrosion resistance and low neutron absorption cross-section. The oxide layer that is formed on the surface of these alloys is meant to be the barrier between the metal and the corrosive environment. READ MORE