Sökning: "flight distance"

Visar resultat 1 - 5 av 38 avhandlingar innehållade orden flight distance.

1. 1. Feathers by day, membranes by night - Aerodynamic performance in bird and bat flight

   Författare :Florian Muijres; Evolutionär ekologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; animal flight; aerodynamics; vortex wake; actuator disk; flight performance; span efficiency; bird; bat; wind tunnel; PIV; Pied Flycatcher; Glossophaga soricina; Leptonycteris yerbabuenae;

   Sammanfattning : The efficiency and performance of a flying animal is directly related to the aerodynamics around its body and flapping wings. Here, I have developed methods for quantifying the wake dynamics around a flying animal. The results are used to estimate the aerodynamic performance of flapping flight. LÄS MER

3. 2. Adaptive flexibility in migratory behaviour of shorebirds

   Författare :Johanna Grönroos; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Bird migration; compensation; departure decision; flight distance; migration speed; migration strategy; orientation; shorebird; stopover; wind drift; wind selectivity;

   Sammanfattning : The phenomenon of bird migration has long fascinated us humans and it has prompted questions like where do they go or come from and how do they find their way? Arctic shorebirds are well known for their spectacular long-distance migrations with some species travelling more than 10 000 km every spring and autumn, and some even cover this distance in one single nonstop flight. The aim of my thesis was to investigate the flexibility of Arctic shorebirds when it comes to orientation behaviour, departure behaviour and migration strategy. LÄS MER

4. 3. Movements in the dark : flying, landing and walking in insects

   Författare :THERESE REBER; Funktionell zoologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; insect; vision; light intensity; bumblebee; retina; behavioural adaptation; flight; landing; dung beetle; nocturnal adaptation; sky compass; straight-line orientation;

   Sammanfattning : Flying, as well as walking insects rely on vision to regulate locomotion, even in the dark when the visual system is much less reliable. To manage visual control of these behaviours at low light intensities, many insects have evolved optical adaptations, such as larger facet lenses and wider rhabdoms, and neural adaptations, such as spatial and temporal summation, to increase their visual sensitivity. LÄS MER

5. 4. On improving efficiency of flight using optimization

   Författare :Marianne Jacobsen; Ulf Ringertz; Virginia Torczon; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vehicle engineering; Farkostteknik;

   Sammanfattning : In this thesis, optimization is used to improve the performance of aircraft. The focus is on operating current generation aircraft more efficiently rather than designing new aircraft. Drag minimization and aircraft trajectory optimization is used to increase efficiency. LÄS MER

7. 5. Fuel and fly: adaptations to endurance exercise in migrating birds

   Författare :Anders Kvist; Bröstcancer-genetik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water balance; flight power; phenotypic flexibility; energy assimilation; basal metabolism; Animal ecology; Djurekologi;

   Sammanfattning : Birds on migration alternate between consuming fuel stores during flights and accumulating fuel stores during stopovers. This thesis highlights some of the ways in which migrating birds have adapted to the different demands of fuelling and flight. Most of the time on migration is spent at stopover sites accumulating fuel stores. LÄS MER