Search for dissertations about: "oxygen"

Showing result 6 - 10 of 2631 swedish dissertations containing the word oxygen.

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

   Author : Urban Öjteg; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Kappa number; lignins; Nitric acid; Magnesium; spent liquors; viscosity; softwood; oxygen bleaching; Nitrogen dioxide; Manganese; Oxygen; Nitrogen oxides; pretreatment; Kraft pulp;

   Abstract : 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). READ MORE

4. 7. Oxygen Vacancy Chemistry in Ceria

   Author : Jolla Kullgren; Kersti Hermansson; Shluger Alex; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Ceria; Density Functional Theory; Oxygen storage; Nano crystals; Sulfur poisoning; Chemistry with specialization in Inorganic Chemistry; Kemi med inriktning mot oorganisk kemi;

   Abstract : Cerium(IV) oxide (CeO2), ceria, is an active metal oxide used in solid oxide fuel cells and for the purification of exhaust gases in vehicle emissions control. Behind these technically important applications of ceria lies one overriding feature, namely ceria's exceptional reduction-oxidation properties. READ MORE

5. 8. Design and Operation of a 10 kWth Chemical-Looping Combustor for Solid Fuels

   Author : Nicolas Berguerand; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Solid Fuel Conversion; Chemical-Looping Combustion; Oxygen Carrier; Ilmenite; Carbon Dioxide Capture; Oxygen Transfer; Gas Conversion; Oxygen Demand;

   Abstract : Chemical-looping combustion (CLC) is a new fuel conversion technology with inherent CO2 capture. In this process, the fuel and the combustion air are never mixed and the oxygen is transferred to the fuel via an oxygen carrier in the form of a metal oxide circulating between two reactors, e.g. READ MORE

6. 9. Steel converter slag as an oxygen carrier

   Author : Fredrik Hildor; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Steel converter slag; Biomass; Oxygen carrier; LD slag; Oxygen carrier aided combustion; Chemical looping;

   Abstract : Thermal conversion of fuels can be used to produce heat and power in addition to chemicals. In order to be aligned with climate targets, it is necessary that such systems do not emit carbon dioxide to the atmosphere. Carbon capture and storage (CCS) can be used together with fuel conversion systems to prevent CO2 from entering the atmosphere. READ MORE

7. 10. Internal oxygen transport to below-ground parts: importance for emergent macrophytes

   Author : Viveka Vretare Strand; Biologiska institutionen; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Växtekologi; Plant ecology; water depth; zonation; phenotypic plasticity; biomass allocation; pressurised ventilation; oxygen; Phragmites australis; emergent macrophytes; common reed; Hydrobiology; marine biology; aquatic ecology; limnology; Marinbiologi; limnologi; akvatisk ekologi; Ecology; Ekologi;

   Abstract : This thesis examines factors regulating growth and distribution of emergent plants with focus on effects of oxygen supply to the roots. Greenhouse experiments revealed that P. australis acclimatizes to specific water depths with phenotypic plasticity. READ MORE