TY - GEN A1 - Schimka, Selina A1 - Lomadze, Nino A1 - Rabe, Maren A1 - Kopyshev, Alexey A1 - Lehmann, Maren A1 - von Klitzing, Regine A1 - Rumyantsev, Artem M. A1 - Kramarenko, Elena Yu. A1 - Santer, Svetlana T1 - Photosensitive microgels containing azobenzene surfactants of different charges T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - We report on light sensitive microgel particles that can change their volume reversibly in response to illumination with light of different wavelengths. To make the anionic microgels photosensitive we add surfactants with a positively charged polyamine head group and an azobenzene containing tail. Upon illumination, azobenzene undergoes a reversible photo-isomerization reaction from a trans- to a cis-state accompanied by a change in the hydrophobicity of the surfactant. Depending on the isomerization state, the surfactant molecules are either accommodated within the microgel (trans-state) resulting in its shrinkage or desorbed back into water (cis-isomer) letting the microgel swell. We have studied three surfactants differing in the number of amino groups, so that the number of charges of the surfactant head varies between 1 and 3. We have found experimentally and theoretically that the surfactant concentration needed for microgel compaction increases with decreasing number of charges of the head group. Utilization of polyamine azobenzene containing surfactants for the light triggered remote control of the microgel size opens up a possibility for applications of light responsive microgels as drug carriers in biology and medicine. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 461 KW - ph-responsive microgels KW - co-monomer content KW - drug-delivery KW - photoresponsive surfactants KW - metal nanoparticles KW - swelling behavior KW - temperature KW - particles KW - collapse KW - hydrogels Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413528 SN - 1866-8372 IS - 461 ER - TY - GEN A1 - Vaz da Cruz, Vinicius A1 - Ertan, Emelie A1 - Couto, Rafael C. A1 - Eckert, Sebastian A1 - Fondell, Mattis A1 - Dantz, Marcus A1 - Kennedy, Brian A1 - Schmitt, Thorsten A1 - Pietzsch, Annette A1 - Guimarães, Freddy F. A1 - Ågren, Hans A1 - Gel'mukhanov, Faris A1 - Odelius, Michael A1 - Föhlisch, Alexander A1 - Kimberg, Victor T1 - A study of the water molecule using frequency control over nuclear dynamics in resonant X-ray scattering T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - In this combined theoretical and experimental study we report a full analysis of the resonant inelastic X-ray scattering (RIXS) spectra of H2O, D2O and HDO. We demonstrate that electronically-elastic RIXS has an inherent capability to map the potential energy surface and to perform vibrational analysis of the electronic ground state in multimode systems. We show that the control and selection of vibrational excitation can be performed by tuning the X-ray frequency across core-excited molecular bands and that this is clearly reflected in the RIXS spectra. Using high level ab initio electronic structure and quantum nuclear wave packet calculations together with high resolution RIXS measurements, we discuss in detail the mode coupling, mode localization and anharmonicity in the studied systems. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 781 KW - raman-scattering KW - vibrational structure KW - fast dissociation KW - auger spectrum KW - liquid water KW - spectroscopy KW - emission KW - collapse KW - states KW - vapor Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436901 SN - 1866-8372 IS - 781 SP - 19573 EP - 19589 ER - TY - GEN A1 - Feldmann, Johannes A1 - Levermann, Anders T1 - Similitude of ice dynamics against scaling of geometry and physical parameters T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - The concept of similitude is commonly employed in the fields of fluid dynamics and engineering but rarely used in cryospheric research. Here we apply this method to the problem of ice flow to examine the dynamic similitude of isothermal ice sheets in shallow-shelf approximation against the scaling of their geometry and physical parameters. Carrying out a dimensional analysis of the stress balance we obtain dimensionless numbers that characterize the flow. Requiring that these numbers remain the same under scaling we obtain conditions that relate the geometric scaling factors, the parameters for the ice softness, surface mass balance and basal friction as well as the ice-sheet intrinsic response time to each other. We demonstrate that these scaling laws are the same for both the (two-dimensional) flow-line case and the three-dimensional case. The theoretically predicted ice-sheet scaling behavior agrees with results from numerical simulations that we conduct in flow-line and three-dimensional conceptual setups. We further investigate analytically the implications of geometric scaling of ice sheets for their response time. With this study we provide a framework which, under several assumptions, allows for a fundamental comparison of the ice-dynamic behavior across different scales. It proves to be useful in the design of conceptual numerical model setups and could also be helpful for designing laboratory glacier experiments. The concept might also be applied to real-world systems, e.g., to examine the response times of glaciers, ice streams or ice sheets to climatic perturbations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 564 KW - grounding line motion KW - full-stokes model KW - West Antarctica KW - sheet models KW - Pine Island KW - stream-B KW - shelf KW - flow KW - sensitivity KW - collapse Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412441 SN - 1866-8372 IS - 564 SP - 1753 EP - 1769 ER - TY - GEN A1 - Frieler, Katja A1 - Mengel, Matthias A1 - Levermann, Anders T1 - Delaying future sea-level rise by storing water in Antarctica T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Even if greenhouse gas emissions were stopped today, sea level would continue to rise for centuries, with the long-term sea-level commitment of a 2 degrees C warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide, we investigate, from an ice-dynamic perspective, the possibility of delaying sea-level rise by pumping ocean water onto the surface of the Antarctic ice sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80% of the additional ice requires placing it at a distance of at least 700 km from the coastline. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mmyr(-1) will exceed 7% of the current global primary energy supply. At the same time, the approach offers a comprehensive protection for entire coastlines particularly including regions that cannot be protected by dikes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 533 KW - carbon-dioxide emissions KW - ice-sheet KW - climate-change KW - model KW - collapse KW - commitment KW - Greenland KW - discharge KW - project KW - surface Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410234 SN - 1866-8372 IS - 533 ER -