Sökning: "air electrodes"

Visar resultat 6 - 10 av 38 avhandlingar innehållade orden air electrodes.

1. 6. Enhancements in Dielectric Response Characterization of Insulation Materials

   Författare :Xiangdong Xu; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; harmonic limited waveform; air reference method; contact-free electrode; geometric corrections.; frequency domain spectroscopy; Dielectric characterization;

   Sammanfattning : The increasing demand of integrating various renewable energy recourses in power system requires extensive use of power electronic solutions, such as HVDC and FACTS, as these techniques allow energy conversion between different frequencies and serves to stabilize the network. Consequently, electric stresses other than traditional 50/60 Hz sinusoidal voltage stress are acting on high voltage insulation materials. LÄS MER

3. 7. Characterization of Reaction Products in the Li-O2 Battery Using Photoelectron Spectroscopy

   Författare :Reza Younesi; Kristina Edström; Patrik Johansson; Fredrik Björefors; Gabriel Veith; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Li-O2 Battery; Surface Characterization; Lithium-Air Battery; Photoelectron Spectroscopy; XPS; Kemi med inriktning mot materialkemi; Chemistry with specialization in Materials Chemistry; Chemistry with specialization in Physical Chemistry; Kemi med inriktning mot fysikalisk kemi;

   Sammanfattning : The rechargeable Li-O2 battery has attracted interest due to its high theoretical energy density (about 10 times better than today’s Li-ion batteries). In this PhD thesis the cycling instability of the Li-O2 battery has been studied. LÄS MER

4. 8. Life cycle assessment of electric vehicle batteries and new technologies

   Författare :Mats Zackrisson; Magnus Wiktorsson; Martin Kurdve; Christina Jönsson; Anders Nordelöf; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; life cycle assessment; LCA; electric vehicle; sustainability; eco-design; Production Engineering; Industriell produktion;

   Sammanfattning : Electrification of vehicles has for decades been explored as a possible solution to the problem of climate change. Today, in 2021, the issue is no longer whether the electrification of vehicle fleets ought to happen but rather how it can be achieved with as little environmental impact as possible. LÄS MER

5. 9. Electrode degradation in proton exchange membrane fuel cells

   Författare :Alejandro Oyarce; Göran Lindbergh; Carina Lagergren; Steven Holdcroft; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; PEMFC; PEFC; Porous electrodes; Carbon corrosion; Carbon nanotubes; Carbon fibers; Polyhedral carbon nanofoams; Phosphonated hydrocarbon ionomer; Mass-transport losses; Electrode morphology; Electrode collapse; Start-up and shut-down; System strategies; Stainless steel; Bi-polar plates; In-situ contact resistance.;

   Sammanfattning : The topic of this thesis is the degradation of fuel cell electrodes in proton exchange membrane fuel cells (PEMFCs). In particular, the degradation associated with localized fuel starvation, which is often encountered during start-ups and shut-downs (SUs/SDs) of PEMFCs. At SU/SD, O2 and H2 usually coexist in the anode compartment. LÄS MER

7. 10. Charge Accumulation in Hybrid High Voltage Insulation

   Författare :Mats Sjöberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric barrier; charge accumulation; high voltage; dielectric barrier discharge; dielectric coating; hybrid insulation; electric field distribution; discharge modelling; breakdown strength; charge conditioning;

   Sammanfattning : This thesis deals with the novel idea of controlling the electric stress or field distribution in a hybrid air - solid-dielectric high voltage insulation by promoting accumulation of surface charges on the internal interfacial layers in the combined (hybrid) dielectric structure. Primarily, applications are expected to be found in high voltage dc systems and as a method to improve the resistance against insulation failure by overvoltages, e. LÄS MER