Sökning: "local stability"

Visar resultat 6 - 10 av 345 avhandlingar innehållade orden local stability.

  1. 6. Stability and complexity of ecosystems - Global interaction constraints, landscape and extinctions

    Författare :Susanne Pettersson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Complexity; Collapse; Stability; Ecosystems; Extinctions; Population dynamics; spatial heterogeneity; Dynamical systems; dispersal;

    Sammanfattning : Human society's expansion and demand for both biotic and abiotic natural resources exert a large pressure on ecosystems around the globe. Ecosystems are complex networks of species interacting with each other and their physical surroundings. LÄS MER

  3. 7. On stability, transition and turbulence in three-dimensional boundary-layer flows

    Författare :Seyed Mohammd Hosseini; Ardeshir Hanifi; Spencer Sherwin; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Receptivity; stability; optimal growth; three-dimensional bound- ary layers; crossflow instability; roughness control; freestream turbulence; sec- ondary instability; transition; turbulence;

    Sammanfattning : A lot has changed since that day on December 17, 1903 when the Wright brothers made the first powered manned flight. Even though the concepts behind flying are unaltered, appearance of stat-of-the-art modern aircrafts has undergone a massive evolution. LÄS MER

  4. 8. Wind Power - Added Value for Network Operation

    Författare :Nayeem Ullah; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; torsional oscillation; reactive power ancillary service; voltage stability; power system simulator.; STATCOM; non-minimum phase system; Variable speed wind turbine; frequency control; sensitivity analysis; transient stability; small-signal stability;

    Sammanfattning : This dissertation deals with the investigation on different value added properties of variable speed wind turbines (VSWT) that stem from the flexible controllability of converter interfaced wind turbines (WT). Improvements in voltage and transient stability of a nearby grid, small-signal stability improvement on the power system, frequency control support for the network operation, as well as thetechnical and the economic issues related to the reactive power ancillary service provision, are among the issues covered. LÄS MER

  5. 9. Efficient Simulation of Wave Phenomena

    Författare :Martin Almquist; Ken Mattsson; Gianluca Iaccarino; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; finite difference method; high-order accuracy; stability; summation by parts; simultaneous approximation term; quantum mechanics; Dirac equation; local time-stepping; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Wave phenomena appear in many fields of science such as acoustics, geophysics, and quantum mechanics. They can often be described by partial differential equations (PDEs). As PDEs typically are too difficult to solve by hand, the only option is to compute approximate solutions by implementing numerical methods on computers. LÄS MER

  7. 10. Structure and energetics of kappa alumina (-Al2O3) calculated from first principles

    Författare :Yashar Yourdshahyan; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; electronic properties; structure; plane-waves; local-density-approximation; stability; ceramics materials; Al2O3 K-phase; pseudopotentials; density-functional theory;

    Sammanfattning : .... LÄS MER