Sökning: "trace gas"

Visar resultat 11 - 15 av 71 avhandlingar innehållade orden trace gas.

1. 11. Measurement of Atmospheric Trace Gas Fluxes using the Relaxed Eddy Accumulation Technique

   Författare :Marcus Olofsson; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : .... LÄS MER

3. 12. Fate of Cu, Cr, As and some other trace elements during combustion of recovered waste fuels

   Författare :Karin Lundholm; Anders Nordin; Britt-Marie Steenari; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; combustion; chemical equilibrium model calculations; trace elements; impregnated wood; waste; thermodynamic data; Cu; Cr; As; Other chemistry; Övrig kemi;

   Sammanfattning : The increased use of biomass and recovered waste fuels in favor of fossil fuels for heat and power production is an important step towards a sustainable future. Combustion of waste fuels also offers several advantages over traditional landfilling, such as substantial volume reduction, detoxification of pathological wastes, and reduction of toxic leaches and greenhouse gas (methane) formation from landfills. LÄS MER

4. 13. Tundra meets atmosphere : Seasonal dynamics of trace gas exchange in the High Arctic

   Författare :Norbert Pirk; Institutionen för naturgeografi och ekosystemvetenskap; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; tundra; methane; carbon dioxide;

   Sammanfattning : Arctic environments have experienced strong warming in recent decades, which is affecting the carbon cycle of tundra ecosystems.Degrading permafrost, diminishing snow cover, and changing hydrology are examples of ongoing processes that affect the land-atmosphere interactions and seasonal ecosystem dynamics. LÄS MER

5. 14. Trace analysis of dioxins and dioxin-like PCBs using comprehensive two-dimensional gas chromatography with electron capture detection

   Författare :Conny Danielsson; Peter Haglund; Karin Wiberg; Jean-Marie Dimandja; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Comprehensive two-dimensional gas chromatography; GC × GC; µECD; PCDDs; PCDFs; dioxins; dioxin-like PCBs; Pressurized liquid extraction; PLE; PLE-C; food; feed; fly ash; soil; Environmental chemistry; Miljökemi;

   Sammanfattning : Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), two groups of struc-turally related chlorinated aromatic hydrocarbons, generally referred to as “dioxins” are of great concern due to their extreme toxicity and presence in all compartments of the environment. Since they occur at very low levels, their analysis is complex and challenging, and there is a need for cost-efficient, reliable and rapid analytical alternatives to the expensive methods in-volving use of gas chromatography high-resolution mass spectrometry (GC-HRMS). LÄS MER

7. 15. Method development for isotope analysis of trace and ultra-trace elements in environmental matrices

   Författare :Nicola Pallavicini; Ilia Rodushkin; Johan Ingri; Frank Vanhaecke; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Applied Geology; Tillämpad geologi;

   Sammanfattning : The increasing load of toxic elements entering the ecosystems, as a consequence of anthropogenic processes, has grown public awareness in the last decades, resulting in a great number of studies focusing on pollution sources, transport, distribution, interactions with living organisms and remediation. Physical/chemical processes that drive the uptake, assimilation, compartmentation and translocation of heavy metals in biota has received a great deal of attention recently, since elemental concentrations and isotopic composition in biological matrices can be used as  probes of both natural and anthropogenic sources. LÄS MER