Sökning: "oxides"

Visar resultat 11 - 15 av 740 avhandlingar innehållade ordet oxides.

1. 11. Optimization of Pretreatment of Kraft Pulp with Nitrogen Oxides

   Författare :Urban Öjteg; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 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

3. 12. Reactions of aqueous radiolysis products with oxide surfaces : An experimental and DFT study

   Författare :Cláudio Miguel Lousada Patrício; Mats Jonsson; Jean-Philippe Renault; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; hydrogen peroxide; hydrogen production; metal; oxides; lanthanide; catalysis; density functional theory; surface; reactions; chemistry; SRA - Energy; SRA - Energi; SRA - Production; SRA - Produktion;

   Sammanfattning : The reactions between aqueous radiolysis products and oxide surfaces are important in nuclear technology in many ways. In solid-liquid systems, they affect (and at the same time are dependent on) both the solution chemistry and the stability of materials under the influence of ionizing radiation. LÄS MER

4. 13. Mechanical properties of semi-solid Al castings : Role of stirring

   Författare :Qing Zhang; Anders E.W. Jarfors; Stefan Jonsson; Tomas Liljenfors; Arne K. Dahle; Johan Ahlström; Jönköping University; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rheometal™ process; aluminum alloys; stirring; segregation; porosity; oxides; ductility; fatigue performance; melt quality;

   Sammanfattning : Aluminum castings have been widely used in the automotive industry to reduce the vehicle's weight. However, the existence of casting defects significantly limits its application. The most common and detrimental defects in aluminum castings are porosity and oxides. LÄS MER

5. 14. Experimental Study on Cold Lap Formation in Tandem Gas Metal Arc Welding

   Författare :Peigang Li; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; oxides; imperfection; spatter; silicon; lack of fusion; overflow; temperature energy; overlap; cold lap; manganese; tandem GMAW;

   Sammanfattning : Tandem gas metal arc welding (GMAW) is a high productivity welding process which is appliedin many industries. However, a type of imperfection, known as cold lap, was revealed thatmostly accompanies the tandem GMAW process. LÄS MER

7. 15. Cold lap formation in Gas Metal Arc Welding of steel : An experimental study of micro-lack of fusion defects

   Författare :Peigang Li; Lars-Erik Svensson; Norbert Enzinger; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tandem GMAW; old laps; lack of fusion; Spatter; Overlap; Overflow; Manganese; Silicon; Oxides; Temperature; Manufacturing and materials engineering; Produktions- och materialteknik;

   Sammanfattning : Cold laps are defined as micro-lack of fusion defects at the weld toe more or less parallel to the surface of the parent plate. These defects are known to negatively influence the fatigue properties of weldments. Previous studies suggest that cold lap formation can not be avoided completely in Gas Metal Arc Welding (GMAW). LÄS MER