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Abstract: The objective of this study is to describe the methodology used to isolate the main voltage loss indicators through a simple and effective treatment of a current interrupt and current sweep. The voltage loss indicators are activation polarization, mass transport, and ohmic losses. The indicators for these losses are the Tafel slope, mass transport resistance and ohmic resistance respectively. The use of this methodology to isolate the individual voltage losses works quite well. Even though there may be some inaccuracies, the trends can be clearly seen. This methodology can be used in any PEMFC system to monitor the state of health of the fuel cell. If this method were to be automated and implemented on a periodic basis, then an on-line measurement of the individual voltage losses could be monitored. The data analysis indicates that a major objective of the controller will be to minimize the mass transport losses by implementing proper temperature control. [Copyright &y& Elsevier]

Abstract: The objectives for microsurgical image-guidance in intracranial procedures are different from the entry-trajectory-target paradigm for stereotactic purposes. From a neurosurgical series of 125 patients with various intracranial pathologies having received surgery that was aided by image guidance, we have derived three basic principles for the successful application of neuronavigation in daily routine: (1) Less is more. Redundant anatomical information-basically all information that is unrelated to surgical landmarks in a particular case-should be omitted from the guiding images. (2) The approach and the surgical target should be visible in a single 3D guiding image. To this end, gradual tuning of the opacity of outer tissue layers in images is the method of choice to outline the in relation to the anatomy that needs to be dissected by the surgeon in order to arrive at the target. (3) All available information on functional tissue properties should be added to the guiding image. Preservation of function has become the single most important demand for neurosurgical procedures. Results of fMRI, DTI and other validated functional studies can readily be added to the structural image. Adhering to these principles may truly enhance the capacities of the surgeon who not only experiences a déjà vue of the individual surgical anatomy when looking through the operating microscope but can also base his intra-operative decisions on invisible functional landmarks. [Copyright &y& Elsevier]