Sökning: "degradation mechanisms"

Visar resultat 1 - 5 av 528 avhandlingar innehållade orden degradation mechanisms.

  1. 1. Free radical mediated cellulose degradation

    Författare :Erik Johansson; KTH; []
    Nyckelord :free radicals; cellulose; polymer; average chain length; bleaching; TCF; ozone; degradation;

    Sammanfattning : This thesis addresses the mechanisms involved in cellulosedegradation in general and Totally Chlorine Free (TCF) bleachingof pulp in particular. The thesis shows that the cellulosedegradation during high consistency ozone bleaching is explainedby free radical chain reactions. LÄS MER

  3. 2. Numerical models for degradation of concrete in hydraulic structures due to long-term contact with water

    Författare :Daniel Eriksson; Anders Ansell; Richard Malm; Erik Nordström; Katja Fridh; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; degradation; deterioration mechanisms; hydraulic structures; air-entrained concrete; multiphase model; long-term moisture conditions; pore size distribution; freezing; partially saturated; finite element method; Civil and Architectural Engineering; Byggvetenskap;

    Sammanfattning : The durability of concrete is of major concern in all types of concrete structures where the combined effect of exposure conditions and the type and quality of the concrete material usually determines the rate of degradation. Furthermore, there are synergy effects between different deterioration mechanisms, which means that the combined rate of degradation is higher than the sum of the individual rates of each mechanism. LÄS MER

  4. 3. Degradation mechanisms and long-term performance of PUR insulation in district heating pipes

    Författare :Alberto Vega; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; mechanical performance; thermal conductivity; District heating pipe; degradation mechanisms; long-term performance; rigid polyurethane foam;

    Sammanfattning : District heating networks are used worldwide, especially in Scandinavian countries and also in many other countries, e.g. Germany, Russia, United States, South Korea and China. From an environmental point of view, district heating networks are a good alternative to more traditional building heating systems. LÄS MER

  5. 4. Deterioration of Polyethylene Exposed to Chlorinated Species in Aqueous Phases : Test Methods, Antioxidants Consumption and Polymer Degradation

    Författare :Wenbin Yu; Ulf Gedde; Sahar Al-Malaika; KTH; []
    Nyckelord :Antioxidants; Polyethylene pipes; Chlorine dioxide; Degradation;

    Sammanfattning : This thesis presents a study of antioxidant depletion in water containing chlorinated species (water containing 10 ppm either Cl2 or ClO2, buffered to pH = 6.8), the degradation products in the aqueous phase, and polyethylene pipe degradation scenarios. LÄS MER

  7. 5. Innovative Bioreactors for the Degradation of Polycyclic Aromatic Hydrocarbons

    Författare :Benoit Guieysse; Bioteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Environmental technology; Bioteknik; Biotechnology; PAH; degradation; aromatic; contaminant; pollutant; bioreactor; organic pollutant; kontroll av utsläpp; Miljöteknik; pollution control;

    Sammanfattning : The development of biological reactors for the treatment of toxic and recalcitrant organic pollutants is a complex task. Firstly, microbial inoculation, acclimation and selection must be optimized to provide the best microflora possible. LÄS MER