Sökning: "Deposition fractions"

Visar resultat 1 - 5 av 28 avhandlingar innehållade orden Deposition fractions.

  1. 1. Air quality assessment and pollution measurements in a typical Sub-Sahara African city: Nairobi, Kenya

    Författare :Samuel Mwaniki Gaita; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Particulate matter pollutants; Source apportionment; Sub-Saharan Africa; deposition fractions;

    Sammanfattning : Exposure to air pollution is detrimental to human health and is reported to cause about 7 million premature deaths in 2012 according to the World Health Organization. In sub-Sahara Africa (SSA) cities, air quality issue is complex due to challenges resulting from the rapid growth of urban population, poor infrastructure development and an exponential increase in number of vehicles. LÄS MER

  3. 2. Airborne particulate matter in a Sub-Saharan Africa city: Nairobi, Kenya, and at an Equatorial high altitude site: Mount Kenya

    Författare :Samuel Mwaniki Gaita; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; X-ray Fluorescence XRF ; Particle Induced X-ray Emission PIXE ; Particulate matter pollutants; Source apportionment; sub-Saharan Africa; Deposition fractions; High- altitude; Free troposphere; Spatial distribution;

    Sammanfattning : In Sub-Saharan Africa (SSA), air quality is gravely understudied despite the existing influential factors such a rapid urbanization and population growth that negatively affect the environment. Majority of urban areas in SSA face challenges that include lack of social services, poor infrastructure development, exponential increase of second-hand vehicles and extensive use of biomass-based fuel for energy needs. LÄS MER

  4. 3. Studies on the alpha-recoil implantation of 214Pb and 210Pb in glass surfaces,Implications for retrospective radon measurements

    Författare :Birgitta Roos; Lund Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; unattached activity; attached activity; retrospective radon measurement; long-lived radon progenies; short-lived radon progenies; deposition velocity; implantation; 222Rn; glass surface; etching; simulation; Nuclear physics; Kärnfysik;

    Sammanfattning : Glass sheets are often used in radon surveys to estimate retrospective radon concentrations, as radon progenies are embedded in the upper surface layer. The implanted activity is influenced by a variety of different environmental conditions. LÄS MER

  5. 4. Microstructure model for Ti-6Al-4V used in simulation of additive manufacturing

    Författare :Corinne Charles Murgau; Lars-Erik Lindgren; Niklas Järvstråt; Robert Pederson; Sören Sjöström; Högskolan Väst; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Titanium alloy; Ti-6Al-4V; Welding; Metal deposition; Additive manufacturing; Wire feed; Finite Element Method; Microstructure model; Johnson-Mehl-Avrami- Kolmogorov; Thermally driven; Production Technology; Produktionsteknik; Manufacturing and materials engineering; Produktions- och materialteknik; Material Mechanics;

    Sammanfattning : This thesis is devoted to microstructure modelling of Ti-6Al-4V. The microstructure and the mechanical properties of titanium alloys are highly dependent on the temperature history experienced by the material. The developed microstructure model accounts for thermaldriving forces and is applicable for general temperature histories. LÄS MER

  7. 5. Permeability modelling and particle deposition mechanisms related to advanced composites manufacturing

    Författare :Markus Nordlund; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Strömningslära; Fluid Mechanics;

    Sammanfattning : Advanced composite materials reinforced by Non-Crimp Fabrics (NCFs) are becoming increasingly popular for high performance, light weight, complex structures, due to their high mechanical properties and relatively cheap production costs. These materials, not only improve the structural properties, but also induce great possibilities for reduced fuel consumptions for aircrafts and automotives, due to their high strength to weight ratio. LÄS MER