Sökning: "Snö"

Visar resultat 16 - 20 av 31 avhandlingar innehållade ordet Snö.

  1. 16. Road surface characterization using near infrared spectroscopy

    Författare :Johan Casselgren; Matti Kutila; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spektroskopi; Väglagsklassificering; Friktion; Väglagskarakterisering; Experimental Mechanics; Experimentell mekanik;

    Sammanfattning : This thesis presents a technology and method for classifying and characterizing different road conditions such as dry asphalt and asphalt covered with water, ice and snow. The method uses light sources of different wavelengths to illuminate the road surface and a detector to measure the reflected light from the road surfaces, dependent on how the surface have absorbed, scattered and polarized the light it is possible to classify the road condition. LÄS MER

  3. 17. To prevent without over-protecting : children and senior citizens injured during outdoor activities

    Författare :Lina Gyllencreutz; Britt-Inger Saveman; Ewa Rolfsman; Robert Ekman; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES;

    Sammanfattning : Background: Injuries are a common public health problem. Non-fatal injuries may result in pain and disabilities. Falls are a common causes of non-fatal injuries and many of these injuries occur during some physical activity. LÄS MER

  4. 18. Surface energy exchange and land-atmosphere interactions of Arctic and subarctic tundra ecosystems under climate change

    Författare :Christian Stiegler; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface energy exchange; Arctic and subarctic tundra; climate change; permafrost; eddy covariance; snow cover; micrometeorology;

    Sammanfattning : The surface energy balance determines the functioning of any ecosystem on the Earth but is still poorly understood in Arctic and subarctic biomes. In a dynamic system, such as the Earth’s climate, any change in its characteristics modifies the exchange of energy, water, and greenhouse gases between the surface and the atmosphere. LÄS MER

  5. 19. Nitrate stable isotopes and major ions in snow and ice from Svalbard

    Författare :Carmen Paulina Vega Riquelme; V. A. Pohjola; R. Pettersson; E. Isaksson; C. E. Bøggild; Kumiko Goto-Azuma; Uppsala universitet; []
    Nyckelord :nitrate stable isotopes; nitrate; NOx proxies; ice cores; percolation; ion relocation; Svalbard; stabila isotoper av nitrat; nitrat; indikator för kväveoxider; iskärnor; perkolation; joniska omlokalisering; Svalbard; Earth Science with specialization in Physical Geography; Geovetenskap med inriktning mot naturgeografi;

    Sammanfattning : Increasing atmospheric reactive nitrogen (Nr), as consequence of human activities, has generated accumulation of nitrate (NO3-) in Arctic regions. The Arctic has fragile nitrogen limited ecosystems that can be altered by increases of dry or wet deposition of Nr. LÄS MER

  7. 20. Treeline dynamics in short and long term perspectives : observational and historical evidence from the southern Swedish Scandes

    Författare :Lisa Öberg; Bengt-Gunnar Jonsson; Leif Kullman; Aage Paus; Mittuniversitetet; []
    Nyckelord :Betula pubescens ssp. czerepanovii; Picea abies; Pinus sylvestris; Larix sibirica; climate; Betula pubescens ssp. czerepanovii; Picea abies; Pinus sylvestris; Larix sibirica;

    Sammanfattning : Treelines in high-mountain regions are constrained by heat deficiency, although the working mechanisms are still not entirely understood. Observational and paleoecological studies on treeline performance may contribute to increased understanding of the treeline phenomenon in general. LÄS MER