Search for dissertations about: "Valve"

Showing result 1 - 5 of 272 swedish dissertations containing the word Valve.

2. 1. Combustion Valve Wear : A Tribological Study of Combustion Valve Sealing Interfaces

   Author : Peter Forsberg; Staffan Jacobson; Rob Dwyer-Joyce; Uppsala universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Combustion valves; wear; tribofilm; test rig; combustion residue; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Abstract : The exhaust valve system of combustion engines experiences a very complex contact situation of frequent impact involving micro sliding, high and varying temperatures, complex exhaust gas chemistry and possible particulates, etc. In addition, the tribological situation in the exhaust valve system is expected to become even worse due to strict future emission regulations, which will require enhanced combustion and cleaner fuels. READ MORE

4. 2. Heart Valve Surgery : Preoperative Assessment and Clinical Outcome

   Author : Laila Hellgren; Elisabeth Ståhle; Mårten Rosenquist; Uppsala universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Surgery; Heart valve surgery; magentic resonance imaging; echocardiography; operative mortality; survival; complications; quality of life; Kirurgi; Surgery; Kirurgi;

   Abstract : A more global analysis of the outcome of heart valve surgery is desirable to reflect the actual benefit for the patient. This thesis focuses on the preoperative assessment of the patient, and the outcome after surgery with regard to operative mortality, long-term survival, valve-related complications, and quality of life. READ MORE

5. 3. Aortic valve imaging - Towards new standards in prosthetic valve endocarditis

   Author : Erika Fagman; Göteborgs universitet; []
   Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; prosthetic valve endocarditis; aortic valve endocarditis; ECG-gated CT; cardiac CT; 18F-FDG PET CT;

   Abstract : Background: Aortic prosthetic valve endocarditis (PVE) is a disease with high mortality, and diagnosis is difficult. Transesophageal echocardiography (TEE) has been the mainstay imaging modality in the diagnostic workup, but TEE has diagnostic shortcomings. Thus, new imaging methods might improve the diagnostic workup of PVE. READ MORE

6. 4. On Gas Dynamics of Exhaust Valves

   Author : Marcus Winroth; P. Henrik Alfredsson; Ramis Örlü; Knud Erik Meyer; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Exhaust valve; poppet valve; dynamic valve; engine modeling; discharge coefficient; Avgasventil; rörlig ventil; motorsimulering; utsläppskoefficient; Engineering Mechanics; Teknisk mekanik;

   Abstract : With increasing effects of global warming, efforts are made to make transportationin general more fuel efficient. When it comes to internal combustion engines,the most common way to improve fuel efficiency is through ‘downsizing’. Downsizingmeans that a smaller engine (with lower losses and less weight) performsthe task of a larger engine. READ MORE

7. 5. Study of a Pneumatic Hybrid aided by a FPGA Controlled Free Valve Technology System

   Author : Sasa Trajkovic; Förbränningsmotorer; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Compressor; Air-motor; Pneuamtc; Pneumatic-hybrid; VVT; Valve; regenerative; Hybrid; Air;

   Abstract : Urban traffic involves frequent acceleration and deceleration. During deceleration, the energy previously used to accelerate the vehicle is mainly wasted on heat generated by the friction brakes. If this energy that is wasted in traditional IC engines could be saved, the fuel economy would improve. READ MORE