Sökning: "methane"

Visar resultat 1 - 5 av 355 avhandlingar innehållade ordet methane.

  1. 1. Abiotic and biotic methane dynamics in relation to the origin of life

    Författare :Nguyen Thanh Duc; David Bastviken; Patrick Crill; Nils Holm; Edward Hornibrook; Stockholms universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; methane; methanogens; methane formation; methane oxidation; lake sediment; olivine; origin of life; geokemi; Geochemistry;

    Sammanfattning : Methane (CH4) plays an important role in regulating Earth’s climate. Its atmospheric concentrations are related to both biotic and abiotic processes. The biotic one can be formed either by chemoautotrophic or heterotrophic pathways by methanogens. LÄS MER

  2. 2. Catalytic combustion of methane

    Författare :Philippe Thevenin; KTH; []
    Nyckelord :catalytic combustion; gas turbine; methane; palladium; alumina; barium; lanthanum; oxidation; preparation; temperature-programmed oxidation TPO ; decomposition; reoxidation; X-ray photoelectron spectroscopy XPS ; metal-support interaction; deactiva;

    Sammanfattning : Catalytic combustion is an environmentally benign technologywhich has recently reached the stage of commercialization.Palladium is the catalyst of choice when considering gasturbines fuelled with natural gas because of its superioractivity for methane oxidation. LÄS MER

  3. 3. Bimetallic palladium catalysts for catalytic combustion of methane

    Författare :Katarina Persson; KTH; []
    Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Chemical engineering; catalytic combustion; gas turbine; methane; palladium; bimetal; morphology; TPO; TEM; EDS; methane activity; stability; pressure; Kemiteknik; Chemical engineering; Kemiteknik;

    Sammanfattning : Catalytic combustion is a promising combustion technique in gas turbines, which results in ultra low levels of NOx, CO and unburned hydrocarbons. Due to the low combustion temperature achieved in catalytic combustion almost no thermal NOx is formed. The focus in this thesis will be on the first stage in a catalytic combustion chamber, i.e. LÄS MER

  4. 4. Methane dynamics in northern lakes : Insights from multi-scale observations

    Författare :Jonathan Schenk; David Bastviken; Magnus Gålfalk; Damien Maher; Linköpings universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Methane; Lakes; Variability; Sampling design; Models;

    Sammanfattning : Methane (CH4) is a potent greenhouse gas which is emitted to the atmosphere from both natural and anthropogenic sources. Current evidence indicates that lakes account for a large part of the global emissions of CH4, but their contribution is difficult to quantify because of large temporal and spatial variability in processes leading to CH4 fluxes from lakes to the atmosphere. LÄS MER

  5. 5. Lake Fluxes of Methane and Carbon Dioxide

    Författare :Eva Podgrajsek; Erik Sahlée; Dennis Baldocchi; Uppsala universitet; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; air-lake gas exchange; carbon dioxide; eddy covariance; floating chambers; methane; waterside convection; Meteorology; Meteorologi;

    Sammanfattning : Methane (CH4) and carbon dioxide (CO2) are two important greenhouse gases. Recent studies have shown that lakes, although they cover a small area of the globe, can be very important natural sources of atmospheric CH4 and CO2. LÄS MER