Sökning: "Nitrogen dioxide"

Visar resultat 1 - 5 av 146 avhandlingar innehållade orden Nitrogen dioxide.

1. 1. Delignification and bleachability of kraft pulps pretreated with nitrogen dioxide

   Författare :Per Larsson; Chalmers University of Technology; []
   Nyckelord :chlorine dioxide; oxygen bleaching; molecular mass; paper properties; ozone bleaching; nitrogen dioxide; kraft pulps; pretreatment; gel permeation chromatography; indulin AT; hydrogen peroxide; consecutive alkaline extractions;

   Sammanfattning : .... LÄS MER

3. 2. Optimization of Pretreatment of Kraft Pulp with Nitrogen Oxides

   Författare :Urban Öjteg; Chalmers University of Technology; []
   Nyckelord :Kappa number; lignins; Nitric acid; Magnesium; spent liquors; viscosity; softwood; oxygen bleaching; Nitrogen dioxide; Manganese; Oxygen; Nitrogen oxides; pretreatment; Kraft pulp;

   Sammanfattning : Modified kraft pulp subjected to oxygen bleaching following pretreatment with 2% nitrogen dioxide for 140 min with the addition of oxygen resulted in low selectivity after subsequent oxygen bleaching. In contrast, pretreatment in the absence of oxygen removed more than 80% of the lignin after oxygen bleaching and still maintained high selectivity (kappa number less than 5 at viscosity 950 dm3/kg). LÄS MER

4. 3. Molecular Beam Studies of Interactions Between Ice Surfaces and Atmospherically Relevant Molecules

   Författare :Liza Romero Lejonthun; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
   Nyckelord :molecular beam; surface; surface scattering; collision; water ice; ice; chlorine; nitrogen oxides; nitrogen monoxide; nitrogen dioxide; dinitrogen tetroxide; dinitrogen pentoxide; nitric acid; helium; graphite;

   Sammanfattning : The discovery of the ozone hole over Antarctica in 1985 was one of the environmental issues that attracted most attention worldwide in the end of the last century. The cause of the ozone hole formation was proven to be coupled to the emission of chlorofluorocarbons (CFCs). LÄS MER

5. 4. Remote Measurements of Ship Emissions

   Författare :Niklas Berg; Chalmers University of Technology; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; airborne; Ship emissions; sulphur dioxide; nitrogen dioxide; DOAS; in situ measurements; carbon dioxide;

   Sammanfattning : The combustion of sulphur-containing fossil fuels gives rise to emissions of sulphurdioxide. Nitrogen oxides are also emitted when fuels are burned. The InternationalMaritime Organization (IMO) has ratified regulations regarding Sulphur Fuel Content(SFC) and NOx emissions from the shipping sector. LÄS MER

7. 5. Porous Cerium Dioxide for Catalytic Applications

   Författare :Mats Lundberg; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; materialteknik; Chemical technology and engineering; Kemiteknik och kemisk teknologi; Materiallära; Material technology; catalysis; transmission electron microscopy; macroporous; mesoporous; cerium dioxide; zirconium dioxide;

   Sammanfattning : Mesoporous cerium dioxide with high crystallinity has been synthesized and studied by TEM, SEM, nitrogen adsorption, PXRD, AFM, and SAXS. The catalytic properties of the materials have been investigated The results of the catalysis experiments were correlated with high resolution TEM investigations of the corresponding material, and it was found that the exposed crystallographic facets play an important role in the conversion of carbon monoxide to carbon dioxide. LÄS MER