Sökning: "valve"
Visar resultat 1 - 5 av 280 avhandlingar innehållade ordet valve.
1. Combustion Valve Wear : A Tribological Study of Combustion Valve Sealing Interfaces
Sammanfattning : 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. LÄS MER
2. Heart Valve Surgery : Preoperative Assessment and Clinical Outcome
Sammanfattning : 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. LÄS MER
3. Aortic valve imaging - Towards new standards in prosthetic valve endocarditis
Sammanfattning : 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. LÄS MER
4. On Gas Dynamics of Exhaust Valves
Sammanfattning : 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. LÄS MER
5. Study of a Pneumatic Hybrid aided by a FPGA Controlled Free Valve Technology System
Sammanfattning : 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. LÄS MER