Sökning: "piercing"

Visar resultat 1 - 5 av 12 avhandlingar innehållade ordet piercing.

  1. 1. Laser cutting and piercing: Experimental and theoretical investigation

    Författare :Jetro Pocorni; Alexander F. H. Kaplan; John Powell; Jan Frostevarg; William O'Neill; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser cutting; laser piercing; efficiency; fibre laser; CO2 laser; high speed imaging; Produktionsutveckling; Manufacturing Systems Engineering; Maskinteknik;

    Sammanfattning : This thesis concerns experimental investigations of laser cutting and piercing, with theoretical and practical discussions of the results. The thesis is made up of an introduction to laser cutting and six scientific Papers. LÄS MER

  3. 2. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

    Författare :Carl-Erik Janson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

    Sammanfattning : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. LÄS MER

  4. 3. Nickel allergy in a Swedish adolescent population and its relation to orthodontic treatment and lifestyle factors

    Författare :Ronny Fors; Berndt Stenberg; Maurits Persson; Arne Hensten; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; adolescent; dental plaque; lifestyle; nickel; oral; orthodontic treatment; patch test; questionnaire; sensitisation; tolerance; Orthodontics; Ortodonti;

    Sammanfattning : Nickel stands out as the main cause of contact allergy in both children and adults, which has given rise to concern and the introduction of regulations by official bodies. Today´s youths are frequently exposed to body piercing and orthodontic treatment. LÄS MER

  5. 4. Experimental and theoretical investigation of the laser cutting process

    Författare :Jetro Pocorni; Ali Khan; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Manufacturing Systems Engineering; Produktionsutveckling; Maskinteknik;

    Sammanfattning : This thesis concerns experimental investigations of laser cutting with theoretical and practical discussions of the results. The thesis is made up of three papers which are linked in such a way that each of them studies a different aspect of laser cutting: In paper I the two major laser types in cutting, namely CO2 and fiber lasers, are compared to each other by a self-defined cut efficiency. LÄS MER

  7. 5. Contact allergy in Swedish adolescents : results from the BAMSE cohort study

    Författare :Maria Lagrelius; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : Background: Contact allergy affects about 20-25% of adults in the general population, but it is not completely clear how common it is among children and adolescents. Contact allergy is caused by skin contact to sensitizing substances. LÄS MER