Sökning: "Carbon 11"

Visar resultat 1 - 5 av 137 avhandlingar innehållade orden Carbon 11.

  1. 1. Carbon fibres from lignin-cellulose precursors

    Författare :Andreas Bengtsson; Monica Ek; Jim Parkås; Daniel Söderberg; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Carbon fibre; Kraft lignin; Cellulose; Dry-jet wet spinning; Kolfiber; Sulfatlignin; Cellulosa; Våtspinning; Luftgapsspinning; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : It is in the nature of the human species to find solutions of complex technical problems and always strive for improvements. The development of new materials is not an exception. One of the many man-made materials is carbon fibre (CF). LÄS MER

  3. 2. Occupational exposure during production of wood pellets in Sweden

    Författare :Katja Hagström; Kåre Eriksson; Gunilla Lindström; Paul Demers; Örebro universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Occupational hygiene; wood dust; resin acids; VOC; variability; determinant of exposure; overexposure; dermal exposure; Occupational medicine; Yrkesmedicin; Enviromental Science; Miljövetenskap;

    Sammanfattning : The aims of the studies underlying this thesis were to assess workers’ air exposure to wood dust and various chemicals, and to evaluate the variability in exposure and occupational dermal exposure to resin acids during the production of wood pellets in Sweden. Personal air measurements of wood dust, monoterpenes, resin acids and nitrogen dioxide (as a marker of diesel exhaust), accompanied by area measurements of these substances, VOCs and carbon monoxide, were performed at up to ten plants. LÄS MER

  4. 3. Instructional technologies in science education : Students’ scientific reasoning in collaborative classroom activities

    Författare :Göran Karlsson; Jonas Ivarsson; Per-Olof Wickman; Göteborgs universitet; []
    Nyckelord :SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; Instructional technologies; animations; design-based research; interaction analysis; science education; Instructional technologies; animations; design-based research; interaction analysis; science education;

    Sammanfattning : This study originates from an interest in how students interpret scientific concepts demonstrated with animated instructional technologies. Currently, science education makes use of diverse kinds of instructional methods. For the advancement of instruction, new technologies have continuously been employed. LÄS MER

  5. 4. Thermodynamic Cycles using Carbon Dioxide as Working Fluid : CO2 transcritical power cycle study

    Författare :Chen Yang; Lundqvist Per; Carlos Infante Ferreria; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Sammanfattning : The interest in utilizing the energy in low‐grade heat sources and waste heat is increasing. There is an abundance of such heat sources, but their utilization today is insufficient, mainly due to the limitations of the conventional power cycles in such applications, such as low efficiency, bulky size or moisture at the expansion outlet (e.g. LÄS MER

  7. 5. Synthesis of 11C-labelled Alkyl Iodides : Using Non-thermal Plasma and Palladium-mediated Carbonylation Methods

    Författare :Jonas Eriksson; Bengt Långström; Philip H. Elsinga; Uppsala universitet; []
    Nyckelord :Organic chemistry; isotopic labelling; carbon-11; alkyl iodides; acrylamides; specific radioactivity; carbonylation; carbon monoxide; non-thermal plasma; PET; Organisk kemi;

    Sammanfattning : Compounds labelled with 11C (β+, t1/2 = 20.4 min) are used in positron emission tomography (PET), which is a quantitative non-invasive molecular imaging technique. It utilizes computerized reconstruction methods to produce time-resolved images of the radioactivity distribution in living subjects. LÄS MER