Sökning: "space webs"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden space webs.

1. 1. Deployment Control of Spinning Space Webs and Membranes

   Författare :Mattias Gärdsback; Anders Eriksson; Gunnar Tibert; Thomas W. Murphey; KTH; []
   Nyckelord :Flexible structures; space webs; membranes; solar sails; solar power systems; deployment control; optimal control; centrifugal force deployment; spin deployment; rotation-free; shell elements; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : Future solar sail and solar power satellite missions require deployment of large and lightweight flexible structures in space. One option is to spin the assembly and use the centrifugal force for deployment, stiffening and stabilization. LÄS MER

3. 2. Numerical and Experimental Studies of Deployment Dynamics of Space Webs and CubeSat Booms

   Författare :Huina Mao; Gunnar Tibert; Arne Nordmark; Anders Eriksson; Keith Seffen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Deployable structure; Space web; Centrifugal force deployment; Deployable boom; Bi-stable tape spring; Fiber-reinforced composite; Viscoelasticity; Aerospace Engineering; Flyg- och rymdteknik;

   Sammanfattning : In this thesis, experiments and simulations are performed to study the deployment dynamics of space webs and space booms, focusing on the deployment and stabilization phases of the space web and the behavior of the bi-stable tape spring booms after long-term stowage.The space web, Suaineadh, was launched onboard the sounding rocket REXUS-12 from the Swedish launch base Esrange in Kiruna on 19 March 2012. LÄS MER

4. 3. Cascading extinctions in food webs : local and regional processes

   Författare :Anna Eklöf; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cascading extinctions; complexity; connectance; dispersal; food web; local dynamics; regional dynamics; resistance; spatial structure; species loss;

   Sammanfattning : Ecological communities all over the world are loosing biodiversity due to different kinds of human activities and there is an urgent need of understanding how those losses affect the function of the ecosystems on which we all depend. The community's response to species losses is likely to depend on both the structure of the local community as well as its interactions with surrounding communities. LÄS MER

5. 4. Species extinctions in food webs : local and regional processes

   Författare :Anna Eklöf; Bo Ebenman; Peter Münger; Marcel Holyoak; Linköpings universitet; []
   Nyckelord :Extinction; food web; metacommunity; dispersal; species loss; migration; habitat fragmentation; connectance; NATURAL SCIENCES; NATURVETENSKAP;

   Sammanfattning : Loss of biodiversity is one of the most severe threats to the ecosystems of the world. The major causes behind the high population and species extinction rates are anthropogenic activities such as overharvesting of natural populations, pollution, climate change and destruction and fragmentation of natural habitats. LÄS MER

7. 5. Bottom-up and top-down regulation of heterogeneous lake food webs

   Författare :Fernando Chaguaceda; Peter Eklöv; Kristin Scharnweber; Lars Tranvik; Blake Matthews; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; food webs; resource coupling; ontogenetic diet shifts; resource specialization; bottom-up; top-down; browning; eutrophication; lake; mesocosms; fatty acids; apparent competition; Biology with specialization in Limnology; Biologi med inriktning mot limnologi;

   Sammanfattning : Food webs are networks of organisms linked by trophic interactions that regulate the responses of ecosystems to environmental change. Such regulation is a result of the effects of resources on the abundance of their consumers (i.e. bottom-up effects) and/or the influence of consumers on the abundance of their resources (i. LÄS MER