Sökning: "barium"

Visar resultat 21 - 25 av 59 avhandlingar innehållade ordet barium.

1. 21. Regulation of ion transport in the gastrointestinal tract : aspects of early development

   Författare :Lena Grahnquist; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :Gastrointestinal transport; early development; ontogeny; ion; sodium; potassium; H ; K -ATPase; Na - K - 2Cl- cotransporter; barium-sensitive potassium channels; Na ; K -; ATPase; dopamine; angiotensin II; glucocorticoids; rat; human;

   Sammanfattning : Ion transport in the gastrointestinal tract is vital for cellular homeostasis and to ensure growth during ontogeny. We have therefore investigated the regulation and maturation of sodium, potassium and hydrogen transport in the gastrointestinal tract. Net jejunal sodium absorption is significantly higher in young as compared to adult rats. LÄS MER

3. 22. Advanced BaZrO3-BaCeO3 Based Proton Conductors Used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs)

   Författare :Junfu Bu; Pär Jönsson; Zhe Zhao; Mogens Mogensen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Solid oxide fuel cells SOFCs ; Intermediate temperature solid oxide fuel cells ITSOFCs ; Electrolyte; Electrochemical impedance spectroscopy EIS ; Barium zirconate BaZrO3 ; Barium cerate BaCeO3 ; Solid-state reaction SSR ; Sintering; Conventional sintering CS ; Solid-state reactive sintering SSRS ; Spark plasma sintering SPS ; Ionic conductivity; Oxygen ion conductivity; Proton conductivity; Electronic conductivity; Oxygen ion conductor; Proton conductor; Oxygen partial pressure OPP ; Composite electrolyte; Materials Science and Engineering; Teknisk materialvetenskap;

   Sammanfattning : In this thesis, the focus is on studying BaZrO3-BaCeO3 based proton conductors due to that they represent very promising proton conductors to be used for Intermediate Temperature Solid Oxide Fuel Cells (ITSOFCs). Here, dense BaZr0.5Ce0.3Y0. LÄS MER

4. 23. Kinetic Studies of NOx Storage and Reduction Catalysts - Flow Reactor Experiments and Microkinetic Modeling

   Författare :Anna Maria Lindholm; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NOx reduction; flow reactor experiments; NOx storage; Pt Ba Al; NSR catalyst; microkinetic modeling; combined NSR and SCR system;

   Sammanfattning : The NOx storage and reduction (NSR) technology is a promising technique to reduce NOx during oxygen excess e.g. in lean burn engine exhaust. A typical NSR catalyst consists of the following components: precious metals, such as platinum, palladium or rhodium, a storage component, usually barium, and a high surface area support, such as γ-alumina. LÄS MER

5. 24. On the solubility of radium sulfate and carbonate

   Författare :Artem Matyskin; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; dissolution; thermodynamics; radium sulfate; radium carbonate; solubility product; precipitation;

   Sammanfattning : Radium is one of the most toxic elements and its concentration in different human activities and migration from man-made wastes provokes a strong interest in environmental science. To be able to model the migration process, reliable experimental thermodynamic data of radium compounds are needed. LÄS MER

7. 25. NOx Storage and Reduction Catalysts. Reduction with Hydrogen and the Influence of Water and Carbon Dioxide

   Författare :Anna Maria Lindholm; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NSR catalyst; Pt Ba Al; H2O; CO2; Pt Al; NOx reduction; H2; NH3 formation; NOx storage; Lean NOx Trap; N2O formation; kinetic modeling; Pt Si;

   Sammanfattning : Environmental concern has increased over the past several years and resulted in stringent emission legislation on NOx, CO, and hydrocarbon emissions from automobile exhausts. Moreover, the demands to improve the fuel efficiency of engines and to lower the CO2 emissions have increased, and a way to meet this is by using lean burn engines which operate with oxygen excess. LÄS MER