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Visar resultat 1 - 5 av 17 avhandlingar som matchar ovanstående sökkriterier.
1. On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells
Sammanfattning : The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. LÄS MER
2. Biomechanical analyses of flywheel resistance exercise : From a space- and ground-based perspective
Sammanfattning : Astronauts suffer degradation of postural muscles and weight-bearing bones during long-duration spaceflight. Resistance exercise is used as a primary countermeasure against these degradations. LÄS MER
3. Alloys in Contact with Molten Salts for Thermal Storage Applications
Sammanfattning : The combination of a concentrated solar power (CSP) plant and a thermal energy storage (TES) system is a promising technology for power generation, in that it overcomes the challenges commonly faced by renewable energy systems, such as intermittency, dispatchability, and the gap between the energy supply and energy demand. The third generation (Gen3) CSP plants are designed to increase plant efficiency by using supercritical carbon dioxide (sCO2) instead of steam for the Brayton cycle gas turbines, requiring a minimum operating temperature of 750°C for the TES materials. LÄS MER
4. Frost-induced deterioration of concrete in hydraulic structures : Interactions between water absorption, leaching and frost action
Sammanfattning : Frost deterioration of concrete can result in severe consequences to the safety, durability and functionality of a structure since it impairs the strength of the concrete. Frost damage may occur to structures that are in contact with water and subjected to frost action. LÄS MER
5. On the Internal Sizing Mechanisms of Paper with AKD and ASA Related to Surface Chemistry, Wettability and Friction
Sammanfattning : Paper and board are hydrophobized (sized) to control the spreading and absorption of waterbased inks and retard the absorption and edge penetration of liquid packaging by aqueous liquids. Alkenyl ketene dimers (AKD) and alkenyl succinic anhydride (ASA) are synthetic sizing agents that are generally used under neutral or slightly alkaline papermaking conditions. LÄS MER