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Visar resultat 6 - 10 av 75 avhandlingar som matchar ovanstående sökkriterier.

  1. 6. Modeling and Optimization of Rare Earth Element Chromatography

    Författare :Mark Max-Hansen; Avdelningen för kemiteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rare Earth Elements; Chromatography; Modeling; Optimization;

    Sammanfattning : The Rare Earth Elements are a group of metals, that are of growing technical and economical importance. Current separation techniques can be detrimental to the environment, and a clean technology for separation has been devised, based on analytical chromatography of the REEs. LÄS MER

  3. 7. Robust Multi-objective Optimization of Rare Earth Element Chromatography

    Författare :Hans-Kristian Knutson; Avdelningen för kemiteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chromatography; Rare earth elements; Modeling; Multi-objective optimization; Robust optimization; Chromatography; Rare earth elements; Modeling; Multi-objective optimization; Robust optimization;

    Sammanfattning : Rare earth elements comprise the metallic elements known as lanthanides as well as scandium and yttrium. They are extensively used in modern technological industries and are considered as strategic commodities in many countries. LÄS MER

  4. 8. Abundance and fractionation of rare earth elements in calcite and other secondary minerals in fractures in the upper kilometre of crystalline bedrock, SE Sweden

    Författare :Olga M. Maskenskaya; Mats Åström; Kjell Billström; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; secondary minerals; rare earth elements; isotopes; crystalline bedrock;

    Sammanfattning : This thesis focuses on the geochemistry of secondary minerals, mainly calcite but also others such as fluorite and Ca/Al silicates, precipitated throughout the last 1.5 billion years in fractures of crystalline rock, SE Sweden. LÄS MER

  5. 9. Microbially mediated manganese oxides enriched in yttrium and rare earth elements in the Ytterby mine, Sweden

    Författare :Susanne Sjöberg; Christophe Dupraz; Per Persson; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; manganese oxidizers; birnessite; yttrium and rare earth elements YREE ; biofilms; shallow subsurface; Ytterby mine; geomicrobiology; microbial geochemistry; manganoxiderare; birnessit; yttrium och sällsynta jordartsmetaller YREE ; underjordisk; Ytterby mine; geomikrobiologi; mikrobiell kemi; geokemi; Geochemistry;

    Sammanfattning : Microorganisms are able to manipulate redox reactions and thus exert extensive control on chemical speciation and element partitioning in nature, affecting the formation and dissolution of certain minerals. One of these redox active elements is manganese (Mn), which in its oxidized states (III/IV), commonly forms Mn oxide-hydroxide minerals. LÄS MER

  7. 10. Origin and mobility of major and key trace elements (Cs, YREEs) in fracture groundwater in the upper 1.2 kilometres of coastal granitoids : Implications for future repositories of spent nuclear fuel

    Författare :Frédéric A. Mathurin; Mats E. Åström; Marcus Laaksoharju; Birgitta Kalinowski; Niklaus Waber; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; fracture groundwater; groundwater mixing; seawater intrusion; water-rock interactions; cation exchange; Cesium; Rare Earth Elements; colloidal speciation; humic substances; dual porosity; inverse modelling; Äspö HRL; Laxemar; Forsmark; eaux de fractures; mélange d eaux; intrusion d eau de mer; interactions eau-roche; échanges cationiques; Césium; Elements Terres Rares; spéciation colloïdale; substances humiques; double porosité; modélisation inverse; Äspö HRL; Laxemar; Forsmark; sprickvatten; grundvatten mixing; havsvattenintrusion; vatten-berg interaction; katjonbyte; cesium; sällsynta jordartsmetaller; kollidal speciation; humusämnen; dual porositet; invers modellering; Äspölaboratoriet; Äspötunneln; Laxemar; Forsmark; Miljövetenskap; Environmental Science;

    Sammanfattning : This thesis focuses on the chemical and isotopic features of groundwater residing in the upper 1.2 km of sparsely fractured crystalline bedrock of the Baltic Shield. LÄS MER