Sökning: "local enrichment"

Visar resultat 1 - 5 av 37 avhandlingar innehållade orden local enrichment.

  1. 1. Species interactions and community structure

    Författare :Peter Frodin; Technology and Social Change (WTS) Centre for Work; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ecology; Ekologi; spatial structure; local stability; enrichment; species interactions; Community structure; population dynamics;

    Sammanfattning : In this theses I have focused on how the mechanisms of species interactions affect community structure. It is well known that certain species may have a particularly strong influence on the structure of a community. What is not fully understood is how to characterize these species that have such a strong impact on community structure. LÄS MER

  3. 2. On-line Sample Pretreatment Based on Membrane Enrichment, Mainly Using Supported Liquid Membranes, for Chromatographic Analysis

    Författare :Yin Shen; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Biological Sample; Environmental Sample; Capillary Gas Chromatography; Ion Chromatography; Automation; Sample Pretreatment; Enrichment; Membrane; Extraction; Analytical chemistry; Analytisk kemi;

    Sammanfattning : The main objective of this work was to construct practical analytical systems for the analysis of environmental and biological samples, using membrane-based techniques for sample pretreatment and chromatography for final analysis. Two types of membrane processes have been applied, with emphasis on automation. LÄS MER

  4. 3. Multiscale interfacial engineering of heterogeneous electrocatalysts : From structural design to mechanistic study

    Författare :Shiqi Zhou; Jiayin Yuan; Martin Oschatz; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; heterogeneous electrocatalysis; electronic structure; coordination environment; single-atom catalysts; strain effect; hydrogen evolution reaction kinetics; charge transfer; electrochemical CO^2 reduction; local enrichment; materialkemi; Materials Chemistry;

    Sammanfattning : In a typical heterogeneous electrocatalytic reaction, for the given active sites, the electronic structure plays a determining role in electron transfer between the active sites and reactant molecules, which impacts the reaction efficiency. Besides the electronic properties of the electrocatalysts, the reaction interface at which the charge transfer occurs plays an important role in the reaction kinetics. LÄS MER

  5. 4. Influence of Oxygen Enrichment on the Oxidation of a Magnetite Pellet Bed During Pot Furnace Induration

    Författare :Anna Eriksson; Charlotte Andersson; Hesham Ahmed; Timo Fabritius; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Oxygen enrichment; Magnetite pellet bed; Oxidation; Pot furnace; Induration; Fossil-free ironmaking; Process Metallurgy; Processmetallurgi;

    Sammanfattning : This study was motivated by the excess oxygen that likely results from the current transition to hydrogen-based Swedish steel production. The potential usability of large amounts of oxygen in a process gas for iron ore pellet induration could improve the process efficiency in terms of fuel consumption and productivity. LÄS MER

  7. 5. Long-term development of subalpine lakes : effects of nutrients, climate and hydrological variability as assessed by biological and geochemical sediment proxies

    Författare :Manuela Milan; Christian Bigler; Monica Tolotti; Richard Bindler; Krystyna Szeroczyńska; Atte Korhola; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Paleolimnology; diatoms; Cladocera; sub-fossil pigments; geochemistry; wavelengthdispersive X-ray fluorescence spectroscopy; Lake Garda; Lake Ledro; reference conditions; nutrient enrichment; climate change; hydrological regime.;

    Sammanfattning : Sediment records of two Italian subalpine lakes (Lake Garda and Lake Ledro) were analyzed in order to reconstruct their ecological evolution over the past several hundred years. A multi-proxy and multi-site approach was applied in order to disentangle the effects of local anthropogenic forcings, such as nutrients, and climate impacts on the two lakes and their catchments. LÄS MER