TY - JOUR A1 - Bernstein, A. A1 - Berger, Georg A1 - Brandt, J. A1 - Wenkel, R. A1 - Gildenhaar, Renate A1 - Zielezinski, T. A1 - Nöbel, D. T1 - Calciumtitanat (Ca4Ti3O10) - ein neues Material für Implantatbeschichtungen KW - Implantatbeschichtung KW - Calciumtitanat KW - Bioaktivität KW - Knochenkontakt KW - Biomaterial-bone-coating of an implant PY - 2004 SN - 1616-0177 SN - 0011-8656 VL - 5 IS - 4 SP - 242 EP - 248 PB - Verl. Neuer Merkur CY - München AN - OPUS4-6010 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schälike, Stefan A1 - Mishra, Kirti Bhushan A1 - Malow, Marcus A1 - Berger, Anka A1 - Wehrstedt, Klaus-Dieter A1 - Schönbucher, A. ED - Pierucci, S. ED - Klemes, J.J. ED - De Rademaeker, E. ED - Fabiano, B. ED - Buratti, S.S. T1 - Mass burning rate of a large TBPB pool fire - experimental study and modeling N2 - Data and prediction for the mass burning rate of a tert-butyl-peroxy-benzoat (TBPB) pool fire (pool diameter = 3 m) is presented. The mass burning rates of TBPB fires are up to six times higher and less dependent on pool diameter compared to hydrocarbon pool fires caused by an additional heat release rate due to exothermic decomposition reaction in the liquid phase. This heat release rate is calculated using a 1st order reaction kinetic obtained from micro calorimetric measurements. A new model is derived considering the heat release rate due to the decomposition reaction which is shown to be 100 % of the heat release rate radiated to the pool surface. With the presented model, including also physical quantities, especially the limiting fuel concentration for upward flame propagation, it is possible to predict the mass burning rates of large TBPB pool fires. The predicted values are in very good agreement with the experiments. T2 - 14th International symposium on loss prevention and safety promotion in the process industries CY - Florence, Italy DA - 12.05.2013 KW - Mass burning rate KW - TBPB (tert-butyl-peroxy benzoat) KW - Pool fire KW - Experimental study KW - Modeling PY - 2013 SN - 978-88-95608-22-8 DO - https://doi.org/10.3303/CET1331143 SN - 1974-9791 N1 - Serientitel: Chemical engineering transactions – Series title: Chemical engineering transactions IS - 31 SP - 853 EP - 858 PB - AIDIC, Associazione Italiana di Ingegneria Chimica CY - Milano AN - OPUS4-28501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Anca-Couce, A. A1 - Zobel, N. A1 - Berger, Anka A1 - Behrendt, F. T1 - Smouldering of pine wood: kinetics and reaction heats N2 - A kinetic model of smouldering of pine wood is determined by thermo-gravimetric analysis (TGA), describing the reactions of wood pyrolysis, wood oxidation and char oxidation. Thermo-gravimetric experiments were conducted with constant heating rates ranging from 2.5 to 10 K/min in atmospheres of pure nitrogen and mixtures of nitrogen and oxygen (with 20.5%, 8.2% and 4.3% O2). At first wood pyrolysis and char oxidation experiments are carried out in an independent way. Then smouldering experiments are conducted, which combine the two previous reactions with wood oxidation. Finally, the heats of the reactions are determined by differential scanning calorimetry (DSC). The results are discussed, compared with the literature and the derived kinetic model is presented, which includes five components: three pseudo-components of wood – representing roughly cellulose, hemi-cellulose and lignin – as well as char and ashes. KW - Smouldering KW - Kinetics KW - TGA KW - Biomass PY - 2012 DO - https://doi.org/10.1016/j.combustflame.2011.11.015 SN - 0010-2180 SN - 1556-2921 VL - 159 IS - 4 SP - 1708 EP - 1719 PB - Elsevier Inc. CY - New York, NY AN - OPUS4-25761 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gildenhaar, Renate A1 - Knabe, C. A1 - Wirth, Cynthia A1 - Linow, Ulf A1 - Houshmand, A. A1 - Berger, Georg T1 - Calcium alkaline phosphate scaffolds for bone regeneration 3D-fabricated by additive manufacturing N2 - Calcium alkaline phosphate granulates can be used for substitution of several bone defects but for the reconstruction of large skeletal parts in the maxillofacial and orthopaedic fields fitted scaffolds are preferable. Within the additive manufacturing methods, the 3D printing process offers exciting opportunities to generate defined porous scaffolds. We used a R1 printer from ProMetal Company, USA, for producing scaffolds directly from a ceramic powder. For this direct free form fabrication technology the powder has to possess a lot of specific properties both for the generation of a stable green body and also for the subsequent sintering preparation. For this printing process we prepared different granules in a fluidized bed process containing Ca2KNa(PO4)2 as main crystalline phase. Granules were characterized by different methods and several sieve fractions were used for preparing disc like and cylindrical parts. The suitability of granules for this printing process was determined by porosity and strength of produced bodies. Next to granules' performance both of these properties can be directly influenced by 3D printing process parameters. With knowledge of suitable process parameters scaffolds with different porosity in a respective desired design can be created. In this study, cylindrical scaffolds with graded porosity were produced for bone regeneration of segmental defects in maxillofacial surgery and dental implantology by tissue engineering. KW - 3D printing KW - Calcium alkaline phosphates KW - Ceramic scaffolds KW - Oral surgery PY - 2012 DO - https://doi.org/10.4028/www.scientific.net/KEM.493-494.849 SN - 1013-9826 N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M. VL - 493-494 SP - 849 EP - 854 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-24989 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernstein, A. A1 - Nöbel, D. A1 - Mayr, H.O. A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Ploska, Ute A1 - Brandt, J. T1 - Influence of Calcium Zirconium Phosphate Containing Coatings on Mineralization of Bone KW - Ceramics KW - Coating KW - Biomaterial KW - Bone KW - Biocompatibility KW - Surface reaction PY - 2008 SN - 1013-9826 VL - 361-363 SP - 641 EP - 644 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-15900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Knabe, C. A1 - Houshmand, A. A1 - Berger, Georg A1 - Ducheyne, P. A1 - Gildenhaar, Renate A1 - Kranz, I. A1 - Stiller, M. T1 - Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype in vitro N2 - Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium-alkali-orthophosphates on osteoblastic phenotype expression and compares this behavior to that of β-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca2P2O7); and a material with a novel crystalline phase Ca10[K/Na](PO4)7 (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis. KW - Bone substitute materials KW - Calcium-alkali-orthophosphate ceramics KW - SaOS-2 cells KW - Osteoblast differentiation KW - Bioactive glass PY - 2008 DO - https://doi.org/10.1002/jbm.a.31383 SN - 1549-3296 SN - 1552-4965 VL - 84A IS - 4 SP - 856 EP - 868 PB - Wiley CY - Hoboken, NJ AN - OPUS4-16658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernstein, A. A1 - Nöbel, D. A1 - Mayr, H.O. A1 - Göbel, F. A1 - Berger, Georg A1 - Ploska, Ute A1 - Gildenhaar, Renate A1 - Brandt, J. T1 - Inhibition of Mineralization by a Calcium Zirconium Phosphate Coating N2 - Bioactive ceramics used as coating materials combine the conductive properties of a bioceramic with the mechanical stability of the metal implant. We studied a calcium zirconium phosphate-containing coating material, FA-CZP [Ca5(PO4)3F, CaZr4(PO4)6], that is relatively insoluble in the biological milieu. The reaction of bone to this material was investigated histologically and histomorphometrically in an animal trial. Cylindrical Ti6Al4V specimens that had been coated with FA-CZP by plasma spraying were implanted in the femoral condyles of rabbits. The implants were left in place for 2, 4, 6, 12, and 14 weeks. FA-CZP led to impaired mineralization of the newly formed bone at the interface. Noncalcified osteoid was found throughout the whole study period. The layer seemed to become thicker with time. The mineralization disorder is evidently caused by zirconium ions. The presence of zirconium in the osteoid in contact with the implant was demonstrated by means of two different staining methods. KW - Mineralization KW - Toxicity KW - Coating(s) KW - Ceramic KW - Bone PY - 2008 DO - https://doi.org/10.1002/jbm.b.31037 SN - 1552-4973 SN - 1552-4981 VL - 86B IS - 2 SP - 422 EP - 429 PB - Wiley CY - Hoboken, NJ AN - OPUS4-17801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Lehmann, Erhard A1 - Stiller, M. A1 - Koch, C. A1 - Ducheyne, P. A1 - Rack, A. A1 - Seligmann, H. A1 - Jonscher, S. A1 - Knabe, C. T1 - A comparative study of the biodegradability of calcium-alkali-orthophosphate ceramics in vitro and in vivo KW - Calcium-alkali-orthophosphate KW - Solubility KW - Biodegradability PY - 2007 SN - 1013-9826 VL - 330-332 SP - 63 EP - 66 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-14528 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernstein, A. A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Mayr, H.O. T1 - In vitro an in vivo behaviour of a ceramic with interconnected macroporosity KW - Ceramics KW - Porosity KW - Biomaterial KW - Bone KW - Biocompatibility KW - Surface reaction PY - 2009 SN - 1013-9826 VL - 396-398 SP - 19 EP - 22 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-17880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ortel, Erik A1 - Hertwig, Andreas A1 - Berger, D. A1 - Esposito, P. A1 - Rossi, A. M. A1 - Kraehnert, R. A1 - Hodoroaba, Vasile-Dan T1 - New approach on quantification of porosity of thin films via electron-excited X‑ray spectra N2 - One of the crucial characteristics of functionalized thin films is their porosity (i.e., the ratio between the pore volume and the volume of the whole film). Due to the very low amount of material per coated area corresponding to thin films, it is a challenge for analytics to measure the film porosity. In this work, we present an Approach to determine the porosity of thin films by means of electron probe microanalysis (EPMA) either by wavelength-dispersive X-ray spectrometry (WDX) or by energy-dispersive X-ray spectrometry (EDX) with a scanning electron microscope (SEM). The procedure is based on the calculation of the film mass deposition from electron-excited X-ray spectra. The mass deposition is converted into film density by division of measured film thickness. Finally, the film porosity is calculated from the measured film density and the density of bulk, nonporous film material. The general applicability of the procedure to determine the porosity is demonstrated on thin templated mesoporous TiO₂ films, dip-coated on silicon wafer, with controlled porosity in the range of 15 to 50%. The high accuracy of the mass deposition as determined from X-ray spectra was validated with independent methods (ICP-OES and weighing). Furthermore, for the validation of the porosity results, ellipsometry, interference fringes method (IFM), and focused ion beam (FIB) cross sectioning were employed as independent techniques. Hence, the approach proposed in the present study is proven to be suited as a new analytical tool for accurate and relatively fast determination of the porosity of thin films. KW - Porosity KW - X-rays KW - EDX KW - Thin film KW - TiO2 KW - Density KW - Mass deposition KW - STRATAGem PY - 2016 UR - http://pubs.acs.org/doi/abs/10.1021/acs.analchem.6b00847 DO - https://doi.org/10.1021/acs.analchem.6b00847 VL - 88 IS - 14 SP - 7083 EP - 7090 PB - ACS Publications CY - 1155 Sixteenth Street N.W., Washington, DC 20036 AN - OPUS4-36911 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -