Sökning: "Residual oxygen"

Visar resultat 1 - 5 av 57 avhandlingar innehållade orden Residual oxygen.

  1. 1. Tailored process gases for laser powder bed fusion

    Författare :Camille Nicole Géraldine Pauzon; Chalmers University of Technology; []
    Nyckelord :Helium; Laser powder bed fusion; AM process productivity; Spatter particles; Residual oxygen; 316L stainless steel; Argon; Nitrogen; Additive manufacturing; Process atmosphere; Process stability; Residual stresses.; Ti-6Al-4V; Alloy 718;

    Sammanfattning : Metal laser powder bed fusion (L-PBF) allows for production of complex components using the energy from a laser to locally melt micron-sized powder following a layer-wise approach. Considerable scientific efforts are focused on addressing the influence of the process parameters on the melting stability and the control of material properties, while developing necessary monitoring and characterization tools. LÄS MER

  2. 2. Some aspects on TCF-bleachability of softwood alkaline pulps

    Författare :Karin Sjöström; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bleachability; chlorine-free bleaching; softwoods; kraft pulps; alkaline sulfite pulps; oxygen; hydrogen peroxide; ozone; hydrogen sulfide ion; hydroxide ion; temperature; sodium ion.; Cellulose and paper engineering; Cellulosa- och pappersteknik;

    Sammanfattning : The bleachability of softwood oxygen delignified pulps has been studied, i.e. the ease (requirement of bleaching chemicals) with which the pulps can be brightened to a target brightness in totally chlorine free (TCF) bleaching stages, including hydrogen peroxide, ozone and chelating agent stages. LÄS MER

  3. 3. Powder degradation during powder bed fusion processing

    Författare :Ahmad Raza; Chalmers University of Technology; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ENGINEERING AND TECHNOLOGY; Laser-based powder bed fusion; Alloy 718; Powder degradation; Oxidation; Electron beam powder bed fusion; Additive manufacturing; AlSi10Mg; Residual oxygen; Spatter particles; Sublimation.;

    Sammanfattning : Powder bed fusion (PBF) techniques, including laser-based powder bed fusion (LB-PBF) and electron beam powder bed fusion (EB-PBF), are two rapidly growing additive manufacturing (AM) processes due to their ability to produce complex geometries in near-net shapes. To attain reproducibility and repeatability in PBF processes, a consistent set of powder properties is vital. LÄS MER

  4. 4. The effects of oxygen on the degradation of lignin model compounds and residual lignin

    Författare :Eva Johansson; KTH; []
    Nyckelord :;

    Sammanfattning : The aim of this work was to achieve a further understandingof the reactivity of lignin structures and residual ligninduring oxygen bleaching. The kinetics of lignin model compoundssuch as diguaiacyl stilbene, propylguaiacol,dipropylbiguaiacol, enol ether and β-aryl ether structuresunder oxygen bleaching conditions have been studied. LÄS MER

  5. 5. Lung aeration and pulmonary gas exchange during general and epidural anaesthesia : Influenced by inspired oxygen concentration and diaphragm shape

    Författare :Adrian Reber; Uppsala universitet; []
    Nyckelord :Medical sciences; Anesthesia: epidural; MEDICIN OCH VÅRD; MEDICINE; MEDICIN; Clinical Physiology; klinisk fysiologi;

    Sammanfattning : Induction of general anaesthesia causes a rapid decrease in functional residual capacity, which can promote alveolar collapse (atelectasis) and airway closure in dependent lung regions. Mismatching of ventilation and perfusion (VA/Q) in the lungs is accompanied by impairment of pulmonary gas exchange. LÄS MER