@article{NkenkeZachowBenzetal.2004, author = {Nkenke, Emeka and Zachow, Stefan and Benz, Michaela and Maier, Tobias and Veit, Klaus and Kramer, Manuel and Benz, St. and H{\"a}usler, Gerd and Neukam, Friedrich and Lell, Michael}, title = {Fusion of computed tomography data and optical 3D images of the dentition for streak artefact correction in the simulation of orthognathic surgery}, series = {Journal of Dento-Maxillofacial Radiology}, volume = {33}, journal = {Journal of Dento-Maxillofacial Radiology}, doi = {10.1259/dmfr/27071199}, pages = {226 -- 232}, year = {2004}, language = {en} } @article{KramerNoackBaumetal., author = {Kramer, Tobias and Noack, Matthias and Baum, Daniel and Hege, Hans-Christian and Heller, Eric J.}, title = {Homogeneous dust emission and jet structure near active cometary nuclei: the case of 67P/Churyumov-Gerasimenko}, abstract = {We compute trajectories of dust grains starting from a homogeneous surface activity-profile on a irregularly shaped cometary nucleus. Despite the initially homogeneous dust distribution a collimation in jet-like structures becomes visible. The fine structure is caused by concave topographical features with similar bundles of normal vectors. The model incorporates accurately determined gravitational forces, rotation of the nucleus, and gas-dust interaction. Jet-like dust structures are obtained for a wide range of gas-dust interactions. For the comet 67P/Churyumov-Gerasimenko, we derive the global dust distribution around the nucleus and find several areas of agreement between the homogeneous dust emission model and the Rosetta observation of dust jets, including velocity-dependent bending of trajectories.}, language = {en} } @article{KramerNoackBaumetal., author = {Kramer, Tobias and Noack, Matthias and Baum, Daniel and Hege, Hans-Christian and Heller, Eric J.}, title = {Dust and gas emission from cometary nuclei: the case of comet 67P/Churyumov-Gerasimenko}, series = {Advances in Physics: X}, volume = {3}, journal = {Advances in Physics: X}, number = {1}, doi = {10.1080/23746149.2017.1404436}, pages = {1404436}, abstract = {Comets display with decreasing solar distance an increased emission of gas and dust particles, leading to the formation of the coma and tail. Spacecraft missions provide insight in the temporal and spatial variations of the dust and gas sources located on the cometary nucleus. For the case of comet 67P/Churyumov-Gerasimenko (67P/C-G), the long-term obser- vations from the Rosetta mission point to a homogeneous dust emission across the entire illuminated surface. Despite the homogeneous initial dis- tribution, a collimation in jet-like structures becomes visible. We propose that this observation is linked directly to the complex shape of the nucleus and projects concave topographical features into the dust coma. To test this hypothesis, we put forward a gas-dust description of 67P/C-G, where gravitational and gas forces are accurately determined from the surface mesh and the rotation of the nucleus is fully incorporated. The emerging jet-like structures persist for a wide range of gas-dust interactions and show a dust velocity dependent bending.}, language = {en} }