@misc{DettmannHuittinenJahnetal.2023,
  author    = {Dettmann, Sophie and Huittinen, Nina Maria and Jahn, Nicolas and Kretzschmar, Jerome and Kumke, Michael and Kutyma, Tamara and Lohmann, Janik and Reich, Tobias and Schmeide, Katja and Azzam, Salim Shams Aldin and Spittler, Leon and Stietz, Janina},
  title     = {Influence of gluconate on the retention of Eu(III), Am(III), Th(IV), Pu(IV), and U(VI) by C-S-H (C/S = 0.8)},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {1318},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-58845},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-588455},
  pages     = {15},
  year      = {2023},
  abstract  = {The retention of actinides in different oxidation states (An(X), X = III, IV, VI) by a calcium-silicate-hydrate (C-S-H) phase with a Ca/Si (C/S) ratio of 0.8 was investigated in the presence of gluconate (GLU). The actinides considered were Am(III), Th(IV), Pu(IV), and U(VI). Eu(III) was investigated as chemical analogue for Am(III) and Cm(III). In addition to the ternary systems An(X)/GLU/C-S-H, also binary systems An(X)/C-S-H, GLU/C-S-H, and An(X)/GLU were studied. Complementary analytical techniques were applied to address the different specific aspects of the binary and ternary systems. Time-resolved laser-induced luminescence spectroscopy (TRLFS) was applied in combination with parallel factor analysis (PARAFAC) to identify retained species and to monitor species-selective sorption kinetics. ¹³C and ²⁹Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to determine the bulk structure and the composition of the C-S-H surface, respectively, in the absence and presence of GLU. The interaction of Th(IV) with GLU in different electrolytes was studied by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS). The influence of GLU on An(X) retention was investigated for a large concentration range up to 10⁻² M. The results showed that GLU had little to no effect on the overall An(X) retention by C-S-H with C/S of 0.8, regardless of the oxidation state of the actinides. For Eu(III), the TRLFS investigations additionally implied the formation of a Eu(III)-bearing precipitate with dissolved constituents of the C-S-H phase, which becomes structurally altered by the presence of GLU. For U(VI) sorption on the C-S-H phase, only a small influence of GLU could be established in the luminescence spectroscopic investigations, and no precipitation of U(VI)-containing secondary phases could be identified.},
  language  = {en}
}
@article{DettmannHuittinenNicolasetal.2023,
  author    = {Dettmann, Sophie and Huittinen, Nina Maria and Nicolas, Jahn and Kretzschmar, Jerome and Kumke, Michael and Kutyma, Tamara and Lohmann, Janik and Reich, Tobias and Schmeide, Katja and Azzam, Salim Shams Aldin and Spittler, Leon and Stietz, Janina},
  title     = {Influence of gluconate on the retention of Eu(III), Am(III), Th(IV), Pu(IV), and U(VI) by C-S-H (C/S = 0.8)},
  series = {Frontiers in Nuclear Engineering},
  volume    = {2},
  journal   = {Frontiers in Nuclear Engineering},
  publisher = {Frontiers Media},
  address   = {Lausanne},
  issn      = {2813-3412},
  doi       = {10.3389/fnuen.2023.1124856},
  pages     = {15},
  year      = {2023},
  abstract  = {The retention of actinides in different oxidation states (An(X), X = III, IV, VI) by a calcium-silicate-hydrate (C-S-H) phase with a Ca/Si (C/S) ratio of 0.8 was investigated in the presence of gluconate (GLU). The actinides considered were Am(III), Th(IV), Pu(IV), and U(VI). Eu(III) was investigated as chemical analogue for Am(III) and Cm(III). In addition to the ternary systems An(X)/GLU/C-S-H, also binary systems An(X)/C-S-H, GLU/C-S-H, and An(X)/GLU were studied. Complementary analytical techniques were applied to address the different specific aspects of the binary and ternary systems. Time-resolved laser-induced luminescence spectroscopy (TRLFS) was applied in combination with parallel factor analysis (PARAFAC) to identify retained species and to monitor species-selective sorption kinetics. ¹³C and ²⁹Si magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were applied to determine the bulk structure and the composition of the C-S-H surface, respectively, in the absence and presence of GLU. The interaction of Th(IV) with GLU in different electrolytes was studied by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS). The influence of GLU on An(X) retention was investigated for a large concentration range up to 10⁻² M. The results showed that GLU had little to no effect on the overall An(X) retention by C-S-H with C/S of 0.8, regardless of the oxidation state of the actinides. For Eu(III), the TRLFS investigations additionally implied the formation of a Eu(III)-bearing precipitate with dissolved constituents of the C-S-H phase, which becomes structurally altered by the presence of GLU. For U(VI) sorption on the C-S-H phase, only a small influence of GLU could be established in the luminescence spectroscopic investigations, and no precipitation of U(VI)-containing secondary phases could be identified.},
  language  = {en}
}
@misc{ReichEtteRenetal.2023,
  author    = {Reich, Karin and Ette, Ottmar and Ren, Haiyan and Kraft, Tobias and Beck, Hanno and Krumpel, Andreas},
  title     = {HiN : Alexander von Humboldt im Netz},
  volume    = {XXIV},
  number    = {46},
  editor    = {Ette, Ottmar and Knobloch, Eberhard},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {2568-3543},
  doi       = {10.25932/publishup-58880},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-588808},
  pages     = {87},
  year      = {2023},
  abstract  = {-Karin Reich: Der Humboldt'sche Magnetische Verein im historischen Kontext -Ottmar Ette, Haiyan REN: Exploring China in Alexander von Humboldt: The Humboldt Center for Transdisciplinary Studies (HCTS), Changsha -Tobias Kraft: Humanist, Wissenschaftler, Akteur? Alexander von Humboldts Rolle im Jahrhundert der Massensklaverei -Hanno Beck: Ein Ehrenb{\"u}rger der Erde. A. von Humboldt und seine Bedeutung -Andreas Krumpel: Ein deutscher Philosoph in Lateinamerika. Nachruf auf Heinz Krumpel},
  language  = {de}
}
@article{RuiperezValienteStaubitzJenneretal.2022,
  author    = {Ruip{\´e}rez-Valiente, Jos{\´e} A. and Staubitz, Thomas and Jenner, Matt and Halawa, Sherif and Zhang, Jiayin and Despujol, Ignacio and Maldonado-Mahauad, Jorge and Montoro, German and Peffer, Melanie and Rohloff, Tobias and Lane, Jenny and Turro, Carlos and Li, Xitong and P{\´e}rez-Sanagust{\´i}n, Mar and Reich, Justin},
  title     = {Large scale analytics of global and regional MOOC providers: Differences in learners' demographics, preferences, and perceptions},
  series = {Computers \& education},
  volume    = {180},
  journal   = {Computers \& education},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0360-1315},
  doi       = {10.1016/j.compedu.2021.104426},
  pages     = {17},
  year      = {2022},
  abstract  = {Massive Open Online Courses (MOOCs) remarkably attracted global media attention, but the spotlight has been concentrated on a handful of English-language providers. While Coursera, edX, Udacity, and FutureLearn received most of the attention and scrutiny, an entirely new ecosystem of local MOOC providers was growing in parallel. This ecosystem is harder to study than the major players: they are spread around the world, have less staff devoted to maintaining research data, and operate in multiple languages with university and corporate regional partners. To better understand how online learning opportunities are expanding through this regional MOOC ecosystem, we created a research partnership among 15 different MOOC providers from nine countries. We gathered data from over eight million learners in six thousand MOOCs, and we conducted a large-scale survey with more than 10 thousand participants. From our analysis, we argue that these regional providers may be better positioned to meet the goals of expanding access to higher education in their regions than the better-known global providers. To make this claim we highlight three trends: first, regional providers attract a larger local population with more inclusive demographic profiles; second, students predominantly choose their courses based on topical interest, and regional providers do a better job at catering to those needs; and third, many students feel more at ease learning from institutions they already know and have references from. Our work raises the importance of local education in the global MOOC ecosystem, while calling for additional research and conversations across the diversity of MOOC providers.},
  language  = {en}
}