@article{StaatBaroudTopcuetal.2008,
  author    = {Staat, Manfred and Baroud, G. and Topcu, M. and Sponagel, Stefan},
  title     = {Soft Materials in Technology and Biology - Characteristics, Properties, and Parameter Identification},
  series = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)},
  journal   = {Bioengineering in Cell and Tissue Research / Artmann, Gerhard M. ; Chien, Shu (Eds.)},
  publisher = {Springer},
  address   = {Berlin},
  isbn      = {978-3-540-75408-4},
  pages     = {253 -- 315},
  year      = {2008},
  language  = {en}
}
@misc{SponagelWachowitz1992,
  author    = {Sponagel, Stefan and Wachowitz, Waldemar},
  title     = {Shaft seal : United States Patent 5,143,385 ; date of patent: Sep. 1, 1992 / assignee: Firma Carl Freudenberg},
  publisher = {[United States Patent and Trademark Office]},
  address   = {[Alexandria, VA]},
  pages     = {5 S. : Ill.},
  year      = {1992},
  language  = {en}
}
@article{SponagelKilthauSpies1987,
  author    = {Sponagel, Stefan and Kilthau, G. and Spies, K. H.},
  title     = {Sealing mechanism of lip seals},
  series = {Eleventh 11th International Conference on Fluid Sealing : proceedings of the 11th Internat. Conference on Fluid Sealing, held at Cannes, France 8 - 10 April, 1987 / organised and sponsored by BHRA, the Fluid Engineering Centre. Ed. B. S. Nau},
  journal   = {Eleventh 11th International Conference on Fluid Sealing : proceedings of the 11th Internat. Conference on Fluid Sealing, held at Cannes, France 8 - 10 April, 1987 / organised and sponsored by BHRA, the Fluid Engineering Centre. Ed. B. S. Nau},
  publisher = {Elsevier},
  address   = {London},
  isbn      = {3-540-51383-3},
  pages     = {748 -- 772},
  year      = {1987},
  language  = {en}
}
@article{SponagelBaroudSteffenetal.2002,
  author    = {Sponagel, Stefan and Baroud, G. and Steffen, T. and Wu, J.},
  title     = {Parameter identification for cement infiltration of osteoporotic bone},
  series = {Poromechanics II : Proceedings of the Second Biot Conference on Poromechanics Grenoble, France 26 - 28 August 2002 / ed. by J.-L. Auriault ...},
  journal   = {Poromechanics II : Proceedings of the Second Biot Conference on Poromechanics Grenoble, France 26 - 28 August 2002 / ed. by J.-L. Auriault ...},
  publisher = {Balkema},
  address   = {Lisse [u.a.]},
  isbn      = {90-5809-394-8},
  pages     = {55 -- 58},
  year      = {2002},
  language  = {en}
}
@misc{SponagelGrafGross1989,
  author    = {Sponagel, Stefan and Graf, G{\"u}nter and Groß, Heinz},
  title     = {Method for the manufacture of a sealing ring with a sealing lip having hydrodynamically acting return elements : United States Patent 4,850,097 ; date of patent: Jul. 25, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel},
  publisher = {[United States Patent and Trademark Office]},
  address   = {[Alexandria, VA]},
  pages     = {4 S. : Ill.},
  year      = {1989},
  language  = {en}
}
@misc{SponagelGrafGross1989,
  author    = {Sponagel, Stefan and Graf, G{\"u}nter and Groß, Heinz},
  title     = {Method for manufacturing a sealing ring : United States Patent 4,861,536 ; date of patent: Aug. 12, 1989 / assignee: Firma Carl Freudenberg. Inventors: Gunter Graf ; Heinz Gross ; Stefan Sponagel},
  publisher = {[United States Patent and Trademark Office]},
  address   = {[Alexandria, VA]},
  pages     = {5 S. : Ill.},
  year      = {1989},
  language  = {en}
}
@article{SponagelAkbayBeckeretal.1980,
  author    = {Sponagel, Stefan and Akbay, U. and Becker, E. and Krozer, S.},
  title     = {Instability of slow viscometric flow},
  series = {Mechanics Research Communications. 7 (1980), H. 4},
  journal   = {Mechanics Research Communications. 7 (1980), H. 4},
  isbn      = {0093-6413},
  pages     = {199 -- 204},
  year      = {1980},
  language  = {en}
}
@article{SponagelAkbayBecker1985,
  author    = {Sponagel, Stefan and Akbay, U. and Becker, E.},
  title     = {Instability of plane Couette flow of viscoelastic liquids},
  series = {Journal of non-Newtonian fluid mechanics. 18 (1985), H. 2},
  journal   = {Journal of non-Newtonian fluid mechanics. 18 (1985), H. 2},
  isbn      = {0377-0257},
  pages     = {123 -- 141},
  year      = {1985},
  language  = {en}
}
@article{BaroudWuBohneretal.2003,
  author    = {Baroud, G. and Wu, J.Z. and Bohner, M and Sponagel, Stefan and Steffen, T.},
  title     = {How to determine the permeability for cement infiltration into osteoporotic cancellous bone},
  series = {Medical Engineering \& Physics. 25 (2003), H. 4},
  journal   = {Medical Engineering \& Physics. 25 (2003), H. 4},
  issn      = {1350-4533},
  pages     = {283 -- 288},
  year      = {2003},
  abstract  = {Cement augmentation is an emerging surgical procedure in which bone cement is used to infiltrate and reinforce osteoporotic vertebrae. Although this infiltration procedure has been widely applied, it is performed empirically and little is known about the flow characteristics of cement during the injection process. We present a theoretical and experimental approach to investigate the intertrabecular bone permeability during the infiltration procedure. The cement permeability was considered to be dependent on time, bone porosity, and cement viscosity in our analysis. In order to determine the time-dependent permeability, ten cancellous bone cores were harvested from osteoporotic vertebrae, infiltrated with acrylic cement at a constant flow rate, and the pressure drop across the cores during the infiltration was measured. The viscosity dependence of the permeability was determined based on published experimental data. The theoretical model for the permeability as a function of bone porosity and time was then fit to the testing data. Our findings suggest that the intertrabecular bone permeability depends strongly on time. For instance, the initial permeability (60.89 mm4/N.s) reduced to approximately 63\% of its original value within 18 seconds. This study is the first to analyze cement flow through osteoporotic bone. The theoretical and experimental models provided in this paper are generic. Thus, they can be used to systematically study and optimize the infiltration process for clinical practice.},
  subject      = {Osteoporose},
  language  = {en}
}
@article{SponagelBaroudFalketal.2004,
  author    = {Sponagel, Stefan and Baroud, G. and Falk, R. and Crookshank, M.},
  title     = {Experimental and theoretical investigation of directional permeability of human vertebral cancellous bone for cement infiltration. G. Baroud, R. Falk, M. Crookshank, S. Sponagel, T. Steffen},
  series = {Journal of Biomechanics. 37 (2004), H. 2},
  journal   = {Journal of Biomechanics. 37 (2004), H. 2},
  isbn      = {0021-9290},
  pages     = {189 -- 196},
  year      = {2004},
  language  = {en}
}