Optische und thermodynamische Methoden zur Untersuchung der teilhomogenen Dieselverbrennung

Magdeburg, Univ., Fak. für Maschinenbau, Diss., 2003von Robin Vanhaels

Experimental Methods for Evaluating Components of Turbomachinery, for Use in Automotive Fuel Cell Applications

This paper describes methods and test beds for components of turbomachinery, for use in automotive fuel cell applications at the Ostfalia University of applied sciences. Turbomachinery for use in fuel cell applications is subject to different requirements than those of conventional turbochargers. Therefore, the turbine and the air bearings of an electrical turbocharger will be subject to evaluation. The different boundary conditions in comparison to conventional turbochargers, with less heat and high humidity from the fuel cell, are especially of interest. Air bearings affect the friction and the vibrations/oscillations of the shaft. The methods and test beds need to fulfill the requirements of these types of turbomachinery. The friction test bed is modified with a new coupling solution, to ensure that the driving electric motor in combination with the shaft of the test component complies with the strict tolerances. For this, a magnetic coupling, for use in high-speed applications, is developed and tested on the friction test bed. The fuel cell turbine was adapted to the hot gas test bed and extended turbine maps are determined. To reach high humidity conditions of a fuel cell application, a water injection system is integrated into the test bed

Total joint replacement of hip or knee as an outcome measure for structure modifying trials in osteoarthritis

Objective: The Group for the Respect of Ethics and Excellence in Science (GREES) organized a working group to assess the value of time to joint surgery as a potential therapeutic failure outcome criterion for osteoarthritis (OA) of the hip or knee in the assessment of potential structure modifying agents. Methods: PubMed was searched for manuscripts from 1976 to 2004. Relevant studies were discussed at a 1-day meeting. Results: There are no accepted guidelines for 'time to' and 'indications for' joint replacement surgery. A limited number of trials have examined joint replacement surgery within the study population. Several parameters, particularly joint space narrowing (interbone distance), correlate with surgical intervention. However, at the level of the knee, none of the parameters have positive predictive value for joint replacement surgery better than 30%. In contrast, lack of significant joint space narrowing has a strong negative predictive value for joint replacement surgery (> 90%), that remains after controlling for OA pain severity. Conclusion: At this time, GREES cannot recommend time to joint surgery as a primary endpoint of failure for structure modifying trials of hip or knee OA-as the parameter has sensitivity but lacks specificity. In contrast, in existing trials, a lack of progression of joint space narrowing has predictive value of > 90% for not having surgery. GREES suggests utilizing joint space narrowing (e.g., > 0.3-0.7 mm) combined with a lack of clinically relevant improvement in symptoms (e.g., greater than or equal to 20-25%) for 'failure' of a secondary outcome in structure modifying trials of the hip and knee. (C) 2004 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved