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Bone grafting is widely used for the treatment of cranio-maxillofacial bone injuries. 3D printing of biodegradable Fe alloy is anticipated to be advantageous over current bone grafting techniques. 3D printing offers the fabrication of precise and tailored bone grafts to fit the patient specific bone defect needs. Biodegradable Fe alloy is a good candidate for 3D printing synthetic grafts to regenerate bone tissue without eliciting complications. CALPHAD theoretical models were used to develop new Fe-Mn-Ca/Mg alloys to enhance the degradation rates of traditional Fe-Mn alloys. In vitro experimental results also showed enhanced degradation rates and good cytocompatibility of sintered Fe-Mn-Ca/Mg compacts. 3D printing of Fe-Mn and Fe-Mn-1Ca alloys further demonstrated their feasibility as potentially viable bone grafts for the future.

Membrane electrode assemblies (MEAs) based on radiation‐grafted proton exchange membranes developed at PSI have shown encouraging performance in the past in hydrogen and methanol fuelled polymer electrolyte fuel cells. In this study, the effect of the pre‐treatment of crosslinked radiation‐grafted FEP membranes prior to lamination with the electrodes on the performance of the MEAs was investigated. Two approaches were assessed separately and in combination: (1) the impregnation of the radiation‐grafted membranes with solubilised Nafion®, and (2) the use of a swollen vs. dry membrane. It is found that the combination of coating the membrane with Nafion® ionomer and hot‐pressing the MEA with the membrane in the wet state produce the best single cell performance. In the second part of the study, the durability of an MEA, based on a radiation‐grafted FEP membrane, was investigated. The performance was stable for 4,000 h at a cell temperature of 80 °C. Then, a notable degradation of the membrane, as well as the electrode material, started to occur as a consequence of either controlled or uncontrolled start‐stop cycles of the cell. It is assumed that particular conditions, to which the cell is subjected during such an event, strongly accelerate materials degradation, which leads to the premature failure of the MEA.

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A system for performing locally resolved electrochemical impedance spectroscopy in a segmented polymer electrolyte fuel cell ͑PEFC͒ has been developed. The impedance measurement is carried out for all segments in parallel. Due to this unique fast parallel approach, the measurement period for obtaining a locally resolved impedance spectrum is virtually independent of the number of segments used. The current density distribution and the corresponding locally resolved impedance spectra for a PEFC segmented along a serpentine cathode flow field and operated on pure H 2 /O 2 and H 2 /air are presented and discussed. For low humidity H 2 /O 2 operation, the locally resolved impedance spectra clearly show that the performance loss toward the gas inlets can be attributed to drying effects. For H 2 /air operation, the lower-frequency loops of the local impedance spectra increase in size as a function of position along the channels. The increase becomes more pronounced with decreasing air stoichiometry. This is likely to be due to cumulative flooding of the gas diffusion layer and a decreasing molar fraction of oxygen in the cathodic gas stream. The locally resolved impedance spectra show that large differences in local cell impedance can occur, i.e., the impedance spectrum of the entire cell is of limited value and can be misleading.