This paper summarizes experimental results of an air fed polymer electrolyte membrane fuel cell system HyPM XR 12 (Hydrogenics Corp.) considering fuel cell temperature, stoichiometry and load requirement variations at ambient and low pressure operation. The experimental work realized at a low pressure test facility designed and assembled by the German Aerospace Center, Institute of Engineering Thermodynamics is based on an experimental design. The experimental results confirm reduced fields of fuel cell operation as well as a decreased gross stack performance and efficiency at low operating pressures (950 mbar ≥ p ≥ 600 mbar) for defined fuel cell temperature, stoichiometry and load requirement. In addition, indexes of the operating parameters are introduced characterizing the fuel cell operation with regard to the gross stack performance and efficiency at ambient and low pressure level. The discussion of the results considers analyses of fuel cell humidification.

Multifunctional fuel cell systems are competitive solutions aboard future generations of civil aircraft concerning energy consumption, environmental issues, and safety reasons. The present study compares low-pressure and supercharged operation of polymer electrolyte membrane fuel cells with respect to performance and efficiency criteria. This is motivated by the challenge of pressure-dependent fuel cell operation aboard aircraft with cabin pressure varying with operating altitude. Experimental investigations of low-pressure fuel cell operation use model-based design of experiments and are complemented by numerical investigations concerning supercharged fuel cell operation. It is demonstrated that a lowpressure operation is feasible with the fuel cell device under test, but that its range of stable operation changes between both operating modes. Including an external compressor, it can be shown that the power demand for supercharging the fuel cell is about the same as the loss in power output of the fuel cell due to low-pressure operation. Furthermore, the supercharged fuel cell operation appears to be more sensitive with respect to variations in the considered independent operating parameters load requirement, cathode stoichiometric ratio, and cooling temperature. The results indicate that a pressure-dependent selfhumidification control might be able to exploit the potential of low-pressure fuel cell operation for aircraft applications to the best advantage.

Highlights-We study referrals between a PCP and a specialist.-Optimal payment system calls for markup for either immediate PCP treatment or for the specialist when she refers patients back to the PCP.-Markups for the specialist may be superior because of better rent efficiency.

Am 18. und 19. November 2017 fand, organisiert vom Forschungszentrum HCHE (Hamburg Center for Health Economics) der Universität Hamburg, der diesjährige Workshop des dggö-Ausschusses für Allokation und Verteilung statt. In neun Präsentationen wurden aktuelle Einblicke in den Forschungsstand empirischer, experimenteller und normativer Arbeiten zu Allokations- und Verteilungsfragen im Gesundheitswesen gegeben. Abgerundet wurde der Workshop durch eine Keynote-Lecture von Izabela Jelovac zum Zusammenhang zwischen Anreizen und Problemen des Zugangs in Gesundheitssystemen.

Am 18. und 19. November 2016 fand der Workshop des dgg?-Ausschusses f?r Allokation und Verteilung statt. Er wurde organisiert vom Forschungszentrum CINCH (competent in competition + health) der Universit?t Duisburg-Essen und gab Einblicke in den aktuellen Forschungsstand empirischer und experimenteller Arbeiten in Bezug auf Allokations- und Verteilungsfragen im Gesundheitswesen. Abgerundet wurde der Workshop durch eine Keynote-Lecture von Jeannette Brosig-Koch.