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Visar resultat 1 - 5 av 17 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Railway Open System Tribology

    Författare :Yezhe Lyu; Ulf Olofsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Wheel; Rail; Brake; Environmental conditions; Tribology; Noise; Particle; Hjul; Räl; Broms; Miljöförhållanden; Tribologi; Ljud; Partiklar; Machine Design; Maskinkonstruktion;

    Sammanfattning : Tribology in the railway system is of increasing interest in the new railway era due to the demand for higher speed and load capacity. Since railway vehicles operate in an open environment, their performance depends greatly on temperature, humidity and natural and artificial contaminants. LÄS MER

  3. 2. DISCO - Drivers and Impacts of Coastal Ocean Acidification

    Författare :Laurie Charrieau; Kvartärgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Coastal ocean acidification; Foraminifera; Environmental changes; pH; Salinity;

    Sammanfattning : Ocean acidification, mainly attributed to the increasing anthropogenic CO2 in the atmosphere, is characterised by a lowering pH together with a shift in the sea water carbonate chemistry toward lower concentration of carbonate ions. On the coasts, where the environmental variability is high due to natural and human impacts, ocean acidification mainly affects the frequency, magnitude, and duration of lower pH and lower calcium carbonate saturation events. LÄS MER

  4. 3. Dynamic Thermal Rating for Improved Utilization of Wind Farm Export Systems : A Methodology for Improving Load Profile Estimation of Wind Farm Export Transformers

    Författare :Zhongtian Li; Patrik Hilber; Tor Laneryd; Stefan Ivanell; Nguyen Nga; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dynamic thermal rating; wake effect; turbine availability; transformer lifetime; transformer aging; dynamisk termisk klassificering; väckningseffekt; turbintillgänglighet; transformatorlivslängd; transformatoråldring; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : The power system components connected to renewable energy sources, such as transformers, are often oversized and conservatively loaded. The design of transformers normally ignores the intermittent nature of the connected renewable energy sources (e.g. solar, wind). LÄS MER

  5. 4. New regulators of xylem lignification in arabidopsis

    Författare :Bernadette Sztojka; Hannele Tuominen; Simon Hawkins; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Xylem; lignin; Arabidopsis; secondary cell wall; transcriptional regulation; lignin-biosynthetic gene; S G lignin ratio;

    Sammanfattning : The ability of land plants to grow upright, bear their own weight and withstand adverse environmental conditions is largely dependent on the secondary xylem tissues of the stem. The xylem cells acquire thick secondary cell walls which are composed of cellulose, hemicellulose and lignin. LÄS MER

  7. 5. Behavioural aspects of conservation breeding : Red junglefowl (Gallus gallus) as a case study

    Författare :Jennie Håkansson; Per Jensen; Elsbeth McPhee; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Behaviour; Conservation; Red junglefowl; Gallus gallus; Captivity; Ethology and behavioural ecology; Etologi och beteendeekologi;

    Sammanfattning : Ett stort antal utrotningshotade djurarter ingår idag i bevarandeprogram världen över. Små populationer hålls då i skyddade miljöer, exempelvis i djurparker, och i många fall är målet att återintroducera djur till naturen. LÄS MER