Sökning: "Chlorine"

Visar resultat 21 - 25 av 149 avhandlingar innehållade ordet Chlorine.

  1. 21. Diurnal variation of stratospheric short-lived species

    Författare :Maryam Khosravi; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; chlorine monoxide; short-lived species; Arctic ClO; diurnal variation; tropical middle stratosphere; Arctic stratosphere;

    Sammanfattning : Diurnal variation of stratospheric short-lived speciesMaryam KhosraviChalmers University of TechnologyDepartment of Earth and Space SciencesAbstractThe depletion of ozone in the stratosphere has a direct impact on the amount of ultravioletradiation reaching the Earth’s surface. The ozone abundance and distributionis controlled by the photo-chemical reactions and catalytic cycles involving halogens(chlorine and bromine), odd hydrogen and odd nitrogen species as well as by atmospherictransport. LÄS MER

  3. 22. Development of a regeneration procedure for commercial automotive three-wy catalysts

    Författare :Henrik Birgersson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; deactivation; fouling; sintering; poisoning; palladium; rhodium; regeneration; dispersion; thermal gas treatment; oxy-chlorine; TWC; automotive catalyst; Chemical process equipment; Kemisk apparatteknik;

    Sammanfattning : Car exhaust catalysts were introduced in the early 1980’s, to limit the release of pollutants such as hydrocarbons, carbon monoxides and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). LÄS MER

  4. 23. Degradation of polyethylene pipes distributing chlorinated water : depletion of stabilizers, release of degraded products and polymer degradation

    Författare :Wenbin Yu; Ulf Gedde; Mats Jonsson; Minna Hakkarainen; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; polyethylene pipes; chlorine dioxide; degradation; Polymer chemistry; Polymerkemi;

    Sammanfattning : This thesis presents the study of antioxidants depletions in chlorinated media (10 ppm Cl2 - and ClO2 - aqueous media), polyethylene pipes degradations scenarios and migration of the degraded species to aqueous phase. Pressure testing on pipes and squalane testing with controlled pH aqueous media (6.8 ± 0. LÄS MER

  5. 24. On the Process Development of an ECF Light Bleaching Sequence for the Production of High Quality Softwood Kraft Pulp and Low AOX Formation

    Författare :Sara Starrsjö; Juha Fiskari; Mikael Lindström; Olena Sevastyanova; Maria Boman; Peter Sandström; Mittuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical Engineering; Natural Science; Chemical Pulping; Softwood; Kraft Pulp; Bleaching; ECF light bleaching; Chlorine Dioxide; AOX formation; Delignification; Bleachability;

    Sammanfattning : The aim of this work is to contribute to the process development of the ECF light bleaching sequence Q(OP)D(PO) by providing a better understanding of the bleaching of softwood kraft pulp. There are few published studies on this type of sequence, and more knowledge is needed on how to reduce environmental impact, improve cost-effectiveness and ensure a high pulp quality. LÄS MER

  7. 25. Metall organic vapour phase epitaxy for advanced III-V devices

    Författare :Nils Nordell; Sture Petersson; Gunnar Landgren; Ferdinand Scholz; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Metalorganic vapour phase epitaxy MOVPE ; III-V compound semiconductors; epitaxial uniformity; p-type doping profiles; epitaxial regrowth; chlorine-MOVPE; buried heterostructure laser; heterostructure bipolar transistor; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Metalorganic vapour phase epitaxy (MOVPE) has proven to be a successful method for growth of structures for advanced optoelectronic semiconductor devices in III-V compounds. This thesis deals with technological and process related aspects of MOVPE from an experimental perspective. LÄS MER