Sökning: "nmr luleå"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden nmr luleå.

  1. 1. Solid state 29Si and 27Al magic angle spinning NMR studies of mechanochemically modified cement

    Författare :Karin Johansson; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry of Interfaces; Gränsytors kemi;

    Sammanfattning : Solid state 29Si and 27Al magic angle spinning (MAS) NMR spectroscopy has been used to investigate how mechanochemical modification affects the hydration kinetics, as well as the structural and chemical properties, in cement blends. The modification comprises intensive treatment of rapid hardening Portland cement with condensed silica fume additive in a vibrating grinding mill. LÄS MER

  3. 2. Nuclear magnetic resonance studies on bentonite in complex mixed systems

    Författare :Alexander S. Goryan; Willis Forsling; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bentonite; montmorillonite; 23Na; 31P; 29Si NMR; interaction; ion exchange; sorption; Chemistry of Interfaces; Gränsytors kemi;

    Sammanfattning : In this work 23Na MAS NMR was validated as a successful quantitative method for studies of exchanging sodium in bentonites useful, in particular, for studies of ion-exchange kinetics. Na-enriched bentonites equilibrated in a re-circulated process water at iron-oxide pelletizing plants may acquire properties of Ca-bentonites after already 20 minutes of the equilibration time, since >50 % of sodium ions will be exchanged by calcium ions during first minutes of bentonite placed in contact with the process water. LÄS MER

  4. 3. Water resistance of Scots pine joints produced by linear friction welding

    Författare :Mojgan Vaziri; Lars-Olof Nilsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wood; wood welding; crack; CT scanning; image processing; MRI; microdensitometry; CPMAS C NMR; density; water absorption; tensile-shear strength; Träteknik; Wood Technology;

    Sammanfattning : Wood welding is a mechanical friction process allowing the assembly of timber without any adhesives. The process consists of applying mechanical friction, under pressure, alternately to the two wood surfaces to be welded. LÄS MER

  5. 4. Interactions in MX-80 bentonite/water/electrolyte systems

    Författare :Torbjörn Carlsson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Soil Mechanics; Geoteknik;

    Sammanfattning : The main objective of this work was to study the influence of temperature, water ratio and electrolyte content on the molecular water mobility in water saturated MX-80 bentonite. T a minor extent the influence of pressure, time, and specific surface area on the molecular water mobility was studied. LÄS MER

  7. 5. Changes of Ca and Mg silicate minerals induced by grinding and interaction with water

    Författare :Elena Kalinkina; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry of Interfaces; Gränsytors kemi;

    Sammanfattning : FT-IR spectroscopy, powder XRD, 29Si MAS-NMR, 13C CP/1H-decoupling MAS-NMR, BET surface area and CO2-content measurements have been used to study the processes which occur during dry grinding of Ca and Mg silicate minerals: diopside, enstatite, åkermanite, and wollastonite. In the course of grinding alongside to hydration and amorphisation considerable sorption of atmospheric CO2 by ground minerals occur. LÄS MER