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Visar resultat 1 - 5 av 29 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Adaptive and model-based control in laminar boundary-layer flows

   Författare :Nicolò Fabbiane; Dan S. Henningson; Aimee S. Morgans; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Flow control; Control theory; Optimal control; Adaptive control; Boundary-layer flow; Fluid dynamics; Plasma actuator; Surface hot-wire; Transition delay;

   Sammanfattning : In boundary-layer flows it is possible to reduce the friction drag by breaking the path from laminar to turbulent state. In low turbulence environments, the laminar-to-turbulent transition is dominated by local flow instabilities – Tollmien-Schlichting (TS) waves – that exponentially grows while being con- vected by the flow and, eventually, lead to transition. LÄS MER

3. 2. EF-Tu and RNase E : Essential and Functionally Connected Proteins

   Författare :Disa L. Hammarlöf; Diarmaid Hughes; Måns Ehrenberg; Gerhart Wagner; Richard H Buckingham; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bacterial growth; translation; EF-Tu; RNase E; mRNA; RNA degradation; Molekylär cellbiologi; Molecular Cellbiology; Mikrobiologi; Microbiology;

   Sammanfattning : The rate and accuracy of protein production is the main determinant of bacterial growth. Elongation Factor Tu (EF-Tu) provides the ribosome with aminoacylated tRNAs, and is central for its activity. In Salmonella enterica serovar Typhimurium, EF-Tu is encoded by the genes tufA and tufB. LÄS MER

4. 3. An Investigation of the Influence of Knee Flexion Angle on the Activity of the Triceps Surae Muscles during the Heel-Raise Test

   Författare :Kim Hébert-Losier; S. John Sullivan; Anthony G. Schneiders; José A. García; Univeristy of Otago; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Biomechanics; Electromyography; Triceps surae; Achilles tendon; Plantar flexion; Heel raise test; Physiotherapy; Rehabilitation; Musculoskeletal; Movement analysis; Muscle endurance; Maximum voluntary isometric contraction;

   Sammanfattning : Background: The heel-raise test (HRT) is used in clinical practice and research to assess the triceps suare (TS) muscles. The test involves repetitive unilateral heel-raises in upright stance. The test is administered with the knee straight for gastrocnemius medialis (GM) and lateralis (GL), and with the knee bent for soleus (SOL). LÄS MER

5. 4. Feedback control and modal structures in transitional shear flows

   Författare :Onofrio Semeraro; Dan S. Henningson; Mihailo Jovanoic; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; flow control; flat-plate boundary layer; laminar-turbulent transition; Other engineering mechanics; Övrig teknisk mekanik;

   Sammanfattning :   Two types of shear flows are investigated in this thesis; numerical simulations are performed for the analysis and control of the perturbation arising in a boundary layer over a flat plate, whereas PIV measurements are analysed for the investigation of a confined turbulent jet. Modal structures of the flows are identified: the aim is to understand the flow phenomena and to identify reduced-order models for the feedback control design. LÄS MER

7. 5. On stability and receptivity of boundary-layer flows

   Författare :Nima Shahriari; Ardeshir Hanifi; Dan S. Henningson; Peter J. Schmid; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; boundary layer receptivity; acoustic receptivity; swept-wing flow; crossflow vortices; roughness element; global stability analysis; direct numerical simulation; plasma actuator; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : This work is concerned with stability and receptivity analysis as well as studies on control of the laminar-turbulent transition in boundary-layer flows through direct numerical simulations. Various flow configurations are considered to address flow around straight and swept wings. LÄS MER