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Visar resultat 21 - 25 av 93 avhandlingar som matchar ovanstående sökkriterier.

  1. 21. Land-atmosphere exchange of carbon in a high-Arctic wet tundra ecosystem

    Författare :Torbern Tagesson; BECC: Biodiversity and Ecosystem services in a Changing Climate; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon; methane; carbon dioxide; climate change; Arctic; NDVI; NDWI; micrometeorology; remote sensing; chamber; tundra;

    Sammanfattning : Arctic ecosystems play a key role in the terrestrial carbon (C) cycle, but spa-tially explicit data on the C exchange is scarce in these remote areas. The global warming is especially dominant in the Arctic, and these areas are vul-nerable to climate change. LÄS MER

  3. 22. Polyelectrolyte complexes : Preparation, characterization, and use for control of wet and dry adhesion between surfaces

    Författare :Caroline Ankerfors; Lars Wågberg; Regine von Klitzing; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : This thesis examines polyelectrolyte complex (PEC) preparation, adsorption behaviour, and potential use for control of wet and dry adhesion between surfaces. PEC formation was studied using a jet-mixing method not previously used for mixing polyelectrolytes. LÄS MER

  4. 23. Model studies of cellulose fibers and films and their relation to paper strength

    Författare :Susanna Fält; KTH; []
    Nyckelord :absorption; carboxymethyl cellulose; cellulose fibers; dissolving pulps;

    Sammanfattning : The objectives of this work were (i) to develop a new methodfor the preparation of thin cellulose model films, (ii) to usethese model films for swelling measurements and (iii) to relatethe swelling of fibers and films to the dry strength ofpaper.In the new film preparation method, NMMO(N-methylmorpholine-N-oxide) was used to dissolve cellulose andDMSO (dimethyl sulfoxide) was added to control the viscosity ofthe cellulose solution. LÄS MER

  5. 24. Two-dimensional Nanocomposites Based on Cellulose Nanofibrils and Graphene Oxide

    Författare :Hanieh Mianehrow; Lars Berglund; Aji Mathew; KTH; []
    Nyckelord :Cellulose nanofibrils; graphene oxide; orientation; reinforcement; oxygen barrier; bio-nanocomposite; moisture; molecular adhesion; interfacial shear strength.; Nanocellulosa; grafenoxid; orientering; förstärkning; syrebarriär; bionanokomposit; fukt; molekylär adhesion; skjuvhållfasthet hos gränsytan.; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Two-dimensional (2D) nanocomposites based on cellulose nanofibrils (CNF) and 2D nanomaterials are of interest as sustainable materials combining functional and structural properties. To achieve reinforcement effects from 2D nanomaterials, their orientation and dispersion state in the CNF matrix are important. LÄS MER

  7. 25. The influence of fibre characteristics on bulk and strength properties of TMP and CTMP from spruce

    Författare :Niklas Klinga; Mittuniversitetet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical engineering; Kemiteknik;

    Sammanfattning : This thesis is intended to contribute to an increased knowledge about the influence of fibre characteristics on bulk and strength properties of thermomechanical pulp (TMP) and chemithermomechanical pulp (CTMP) from spruce. It deals with laboratory sheet properties and how they are affected by the conditions during pressing and drying, e.g. LÄS MER