IMECE2003-41368 APPROACH TO MEET AN OVERALL TRANSIENT PERFORMANCE CRITERION OF A PEM FUEL CELL SYSTEM

ABSTRACT Fuel Cells have been intensely researched and developed in the recent decade, where especially the fuel cell MEA (Membrane Electrode Assembly) and stack have been the main focus. Now the system control components surrounding the fuel cell have been given more attention. This paper gives a novel system approach of setting up the demands for control components such as valve actuators for a PEM (Proton Exchange Membrane) fuel cell system in order to meet an overall transient system performance criterion. Overall control considerations are treated, and the major time constants of the sub-systems are analyzed. The result is a method for specifying dynamic performance criteria for the individual control components. By proper selection of the components it can be shown that the electric load buffer may be omitted due to the internal capacitance of the fuel cell. Test results from a 2.5 kW PEM fuel cell test facility show close agreement with simulation results from the novel system approach

Volunteer responder provision of support to relatives of out-of-hospital cardiac arrest patients: a qualitative study

Objectives Smartphone dispatch of volunteer responders for out-of-hospital cardiac arrest (OHCA) is implemented worldwide. While basic life support courses prepare participants to provide CPR, the courses rarely address the possibility of meeting a family member or relative in crisis. This study aimed to examine volunteer responders’ provision of support to relatives of cardiac arrest patients and how relatives experienced the interaction with volunteer responders.Design In this qualitative study, we conducted 16 semistructured interviews with volunteer responders and relatives of cardiac arrest patients.Setting Interviews were conducted face to face and by video and recorded and transcribed verbatim.Participants Volunteer responders dispatched to cardiac arrests and relatives of cardiac arrest patients were included in the study. Participants were included from all five regions of Denmark.Results A thematic analysis was performed with inspiration from Braun and Clarke. We identified three themes: (1) relatives’ experiences of immediate relief at arrival of assistance, (2) volunteer responders’ assessment of relatives’ needs and (3) the advantage of being healthcare educated.Conclusions Relatives to out-of-hospital cardiac arrest patients benefited from volunteer responders’ presence and support and experienced the mere presence of volunteer responders as supportive. Healthcare-educated volunteer responders felt confident and skilled to provide care for relatives, while some non-healthcare-educated volunteer responders felt they lacked the proper training and knowledge to provide emotional support for relatives. Future basic life support courses should include a lesson on how to provide emotional support to relatives of cardiac arrest patients