Search for dissertations about: "S-shaped"

Showing result 1 - 5 of 19 swedish dissertations containing the word S-shaped.

2. 1. Aerodynamic Design and Optimization of Intermediate Ducts for High By-pass Ratio Jet Engines

   Author : Fredrik Wallin; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Intermediate transition ducts; vortex generators; S-shaped ducts; response surface methodology; source term model; optimization;

   Abstract : Demands on improved efficiency and reduced noise levels cause a strive toward high by-pass ratio commercial aero engines. This results in multi-spool aero engines with small high-pressure ratio cores and large fans. The low-pressure system has a lower rotational speed and a larger radius than the high-pressure core system. READ MORE

4. 2. Wafer-level heterogeneous integration of MEMS actuators

   Author : Stefan Braun; Göran Stemme; Martin A. Schmidt; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Microelectromechanical systems; MEMS; silicon; wafer-level; integration; heterogeneous integration; transfer integration; packaging; assembly; wafer bonding; adhesive bonding; eutectic bonding; release etching; electrochemical etching; microvalves; microactuator; Shape Memory Alloy; SMA; NITINOL; TiNi; NiTi; cold-state reset; bias spring; stress layers; crossbar switch; routing; switch; switch array; electrostatic actuator; S-shaped actuator; zipper actuator; addressing; transfer stamping; blue tape; Computer engineering; Datorteknik;

   Abstract : This thesis presents methods for the wafer-level integration of shape memory alloy (SMA) and electrostatic actuators to functionalize MEMS devices. The integration methods are based on heterogeneous integration, which is the integration of different materials and technologies. READ MORE

5. 3. Aerodynamics of an Aeroengine Intermediate Compressor Duct: Effects from an Integrated Bleed System

   Author : Elias Siggeirsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Intermediate Compressor Duct; S-shaped duct; DDES; Hybrid RANS LES; Dual-time-stepping; Bleed system; rotor off-take; SBES; CFD; Turbomachinery;

   Abstract : With the successful development of high-bypass-ratio turbofan engines, major aerodynamic components have been optimized and continuous efficiency improvements are getting harder to maintain. Therefore, to meet the requirements of lower emission of greenhouse gases, auxiliary modules such as intermediate ducts are receiving increasing interest. READ MORE

6. 4. A Large-Scale Facility for Investigation of Intermediate Turbine Ducts: Design, Implementation and Initial Tests

   Author : Lars-Uno Axelsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diffuser; S-shaped duct; wind-tunnel design; gas turbine; turbofan; annular duct; Intermediate turbine duct;

   Abstract : Intermediate turbine ducts are used in modern multi-spool jet engines for guiding the flow from the high-pressure turbine to the low-pressure turbine. The demand for lighter, more efficient and more environmentally friendly aircraft engines requires the new jet engines to have higher by-pass ratios. READ MORE

7. 5. The management of common-pool resources : theoretical essays and empirical evidence

   Author : Ingela Ternström; Handelshögskolan i Stockholm; []
   Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES;

   Abstract : A large part of the poor people in the world is dependent on local natural resources for their survival. Often, these resources are managed as common-pool resources; that is, they are used in common by a limited group of people, who are dependent on each other in their use of the resource. READ MORE