TY - JOUR A1 - Rzepka, M. A1 - Bauer, E. A1 - Reichenauer, G. A1 - Schliermann, T. A1 - Bernhardt, B. A1 - Bohmhammel, K. A1 - Henneberg, E. A1 - Knoll, Uta A1 - Maneck, Heinz-Eberhard A1 - Braue, W. T1 - Hydrogen Storage Capacity of Catalytically Grown Carbon Nanofibers JF - The journal of physical chemistry / B N2 - In 1996, R. T. K. Baker, and N. M. Rodriguez claimed to have synthesized a new type of carbon nanofiber material capable of storing large amounts of hydrogen at room temperature and pressures above 100 bar, thus making it a powerful candidate for a very efficient energy storage system in mobile applications. Consequently, many scientists all over the world tried to test and verify these findings, however, with partly inconsistent results. We present here for the first time independent hydrogen storage measurements for several types of nanofibers, both synthesized by our group following precisely the specifications given in the literature as well as original samples supplied by Rodriguez and Baker for this study. The hydrogen storage capacities at room temperature and pressures up to 140 bar were quantified independently by gravimetric and volumetric methods, respectively. No significant hydrogen storage capacity has been detected for all carbon nanofibers investigated. KW - Energy storage KW - Hydrogen storeage KW - Storage capacity KW - Carbon nanofiber KW - Carbon nanofiber synthesis PY - 2005 DO - https://doi.org/10.1021/jp051371a SN - 1520-6106 SN - 1520-5207 SN - 1089-5647 VL - 109 IS - 31 SP - 14979 EP - 14989 PB - Soc. CY - Washington, DC AN - OPUS4-13763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernhardt, R. A1 - Scharnweber, D. A1 - Müller, B. A1 - Thurner, P. A1 - Schliephake, K. A1 - Wyss, P. A1 - Beckmann, F. A1 - Goebbels, Jürgen A1 - Worch, H. T1 - Comparison of microfocus- and synchrotron X-ray tomography for the analysis of osteointegration around T16AL4V-implants JF - European cells & materials N2 - Micro-computed tomography (µCT) provides quantitative three-dimensional information of bone around titanium implants similar to classical histology. The study, based on an animal model, using cuboid-shaped biofunctionalised Ti6Al4V implants with surrounding bone after 4 weeks, is performed using 3 µCT-systems with X-ray tubes, one synchrotron-radiation-based µCT-system (SRµCT), and classical histology. Although the spatial resolution of the µCTsystems is comparable, only the results of SRµCT agree with results of classical histology. The X-ray tube sources give rise to huge artefacts in the tomograms (interface scattering, beam hardening), which impaired the quantitative analysis of bone up to about 200 µm from the implant surface. Due to the non-destructive character of µCT the specimens can be subsequently examined by classical histology without restriction. The quantitative comparison of bone formation uncovers the strong dependence of the detected amount of newly formed bone from the selected slice. This implies the necessity of 3D analysis. SRµCT and classical histology prove that surface modifications of the titanium implant significantly influence the bone formation. Using SRµCT, the preparation artefacts due to cutting and polishing are excluded. KW - X-ray micro computed tomography KW - Comparison of microfocus and synchrotron radiation KW - Osteointegration KW - Surface modification of titanium implants KW - Histology KW - Bone segmentation KW - Quantification of bone formation PY - 2004 UR - http://www.ecmjournal.org/journal/papers/vol007/vol007a05.php SN - 1473-2262 VL - 7 SP - 42 EP - 51 PB - Univ. of Wales CY - Aberystwyth, Wales AN - OPUS4-5600 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -