Steffen Hardt. Ehsan Ro S. 025108, ISSN 1070-6631, DOI: 10.1063/1.5141165, [Online-Edition: https://doi.org/10.1063/1.5141165], [Artikel] Therefore, such a pump may be used for gas separation. The droplet reciprocates between two aqueous reservoirs under the influence of a DC electric field. “Tears of wine” is a phenomenon that can be observed in wine glasses: Driven by Marangoni stresses, a liquid film crawls up along the glass wall. ‡ hardt@nmf.tu-darmstadt.de; Article Text (Subscription Required) Click to Expand. DNA molecules can be concentrated by electrophoretic accumulation at an interface between two immiscible polymer solutions. Philippe Davy directeur de recherche, CNRS, Rennes Verified email at univ-rennes1.fr. References (Subscription Required) Click to Expand. Together with cooperation partners from the Technion/Israel, we have studied the electroosmotic flow along superhydrophobic surfaces, augmented by gate electrodes. Zu unseren Arbeitsgebieten gehören Gaskinetik auf der Nanoskala, Elektrokinetik, Grenzflächenströmungen, Benetzungsphänomene und Trennprozesse für Biomoleküle. SIAM J. Numer. Tobias Baier Center of Smart Interfaces, TU Darmstadt Verified email at nmf.tu-darmstadt.de. Baier, T., Hardt, S. Gas separation in a Knudsen pump inspired by a Crookes radiometer. Zu unseren Arbeitsgebieten gehören Gaskinetik auf der Nanoskala, Elektrokinetik, Grenzflächenströmungen, Benetzungsphänomene und Trennprozesse für Biomoleküle. Hover over the donut graph to view the FC output for each subject. S. Dehe, B. Rofman, M. Bercovici, and S. Hardt, Electro-osmotic flow enhancement over superhydrophobic surfaces, Physical Review Fluids 5 (2020), 053701. Principal institution: Darmstadt University of Technology (TU Darmstadt) Region: Global Subject/journal group: All The table to the right includes counts of all research outputs for Institute for Nano- and Microfluidics (NMF), TU Darmstadt published between 1 June 2019 - 31 May 2020 which are tracked by the Nature Index. Together with cooperation partners from the Technion/Israel, we have studied the electroosmotic flow along superhydrophobic surfaces, augmented by gate electrodes. Преглед на всички. Institute of Printing Science and Technology, TU Darmstadt did not contribute to any primary research papers from Nature Index journals in the current 12 month window. The theoretical predictions based on linear stability analysis compare favorably with the experimental results. DOI:10.1017/jfm.2019.921. In that case, ring-like structures are formed from the film. T. Baier and S. Hardt, Influence of insoluble surfactants on shear flow over a surface in Cassie state at large Péclet numbers, Journal of Fluid Mechanics 907 (2020), A3. 6 — June 2019. Electroosmotic flow (EOF) induced by surface acoustic waves. We have studied the transfer of chemical species between the two reservoirs mediated by the droplet. Please find below older news relating to research at the Institute for Nano- and Microfluidics. This kind of separation of gas species by mass or size plays an important role for many applications in chemical engineering. Please find below all contacts to board, project coordinators, researchers, administrative and technical staff of the CRC 1194. DOI: 10.1017/jfm.2020.80, Pattern formation in layers of DNA molecules. Reference: M. Shojaeian and S. Hardt, Mass transfer via femtoliter droplets in ping-pong mode, Physical Review Applied 13 (2020), 014015. At a microscopic scale, surfactants, molecules attached to the interface between two fluids, can suffer the same fate, immobilizing the interface upstream of an obstacle. Articles Cited by Co-authors. Issue. Enhancement of electroosmotic flow on superhydrophobic surfaces. For a small particle inside a gas, the fluid dynamics of such problems becomes very involved, since the Navier-Stokes equation is no longer applicable. Your browser does not support the video element. In that case, the viscosity coefficients represent the dissipation due to the presence of particles or surfactants in an average manner. Steffen Hardt Professor, TU Darmstadt Потвърден имейл адрес: nmf.tu-darmstadt.de. Reuse & Permissions. Song Jinlong The School of Mechanical Engineering, Dalian University of Technology Verified email at dlut.edu.cn. Dr. Dharmendra Tripathi Associate Professor, Mathematics, National Institute of Technology Uttarakhand Verified email at nituk.ac.in. hardt@nmf.tu-... +49 6151 16-24274. TU Darmstadt; Maschinenbau; Nano- and Microfluidics; Staff; People Name Working area(s) Contact; Director of the institute Prof. Dr. rer. Tobias Baier Center of Smart Interfaces, TU Darmstadt Потвърден имейл адрес: nmf.tu-darmstadt.de. This kind of separation of gas species by mass or size plays an important role for many applications in chemical engineering. hampe@tvt.tu-... work +49 6151 16-22520. In addition, the flow is entirely pH-independent. We have computed the corresponding drag force on a particle and find that it is much lower than the one predicted by the Navier-Stokes equation. Sort. Intermediate wetting states on superhydrophobic surfaces. We are concerned with transport phenomena in fluids on the nano- and micrometer scale. https://www.fdy.tu-darmstadt.de/fdy/fdystaff/details_17472.de.jsp Electroosmotic flow (EOF) induced by surface acoustic waves. B. Rofman, S. Dehe, V. Frumkin, S. Hardt, and M. Bercovici, Intermediate states of wetting on hierarchical superhydrophobic surfaces, Langmuir 36 (2020), 5517−5523. In: Physics of Fluids, (2), 32. fluid dynamics microfluidics electrokinetics. 4, Iss. Year; Temperature dependence of antiferromagnetic order in the Hubbard model. ‘Super-hydrophobic’ surfaces with embedded gas pockets have been suggested for reducing drag on objects moving through water. A summary of the main results can be found here. S. Dehe, B. Rofman, M. Bercovici, and S. Hardt, Electro-osmotic flow enhancement over superhydrophobic surfaces, Physical Review Fluids 5 (2020), 053701. Physical Review B 70 (12), 125111, 2004. Electronic address: kleebe@geo.tu-darmstadt.de. We find a multitude of intermediate states between the classical Cassie and Wenzel states. ‘Super-hydrophobic’ surfaces with embedded gas pockets have been suggested for reducing drag on objects moving through water. As a stream encounters an obstacle, floating debris sometimes piles up in front of the obstacle, forming a dense layer on the water surface. Via the charges created at the gas-liquid interfaces, the flow velocity can be increased by more than a factor of 10 compared to unstructured surfaces. We have experimentally studied the concentration patterns and formulated a theory describing the pattern formation. Electronic address: hardt@nmf.tu-darmstadt.de. Cited by. We have found a solution to this problem, where a droplet with a diameter of the order of 5 µm serves as carrier for the cargo. Supplemental Material (Subscription Required) Click to Expand. In that context we are especially interested in studying fundamentals, with the intention to pave the way for novel applications. Research; Relationships; 1 August 2019 - 31 July 2020. christophe clanet CNRS, LadHyX, Ecole … Therefore, such a pump may be used for gas separation. Upon touching the reservoir, the droplet reverses its charge and its direction of motion. M. Dietzel and S. Hardt, Electroosmotic flow in small-scale channels induced by surface-acoustic waves, Physical Review Fluids 5 (2020), 123702. Link: https://doi.org/10.1017/jfm.2019.921. Institute for Nano- and Microfluidics (NMF), TU Darmstadt . Issue . Clarendon Press. Verified email at nmf.tu-darmstadt.de. Together with cooperation partners from the Technion/Israel, we have studied the wetting states of hierarchical superhydrophobic surfaces, consisting of an array of micropillars that is decorated with nanoparticles. A sphere moving in the vicinity of a wall experiences an increased fluid-dynamic drag force compared to motion far from solid boundaries, influencing the adsorption of particles at surfaces. We have experimentally studied the concentration patterns and formulated a theory describing the pattern formation. Enhancement of electroosmotic flow on superhydrophobic surfaces. Now imaging shrinking the diameter of the wine glass to one millimeter. Formation of small droplets inside larger droplets, Microfluidic chip with two-phase flow for DNA or protein separation in an electric field, Wetting transition on a superhydrophobic surface, Electroosmotic flow along a superhydrophobic surface induced by a gate electrode. The transition from the Cassie state to these intermediate states is partially reversible. We have studied the transport of gas mixtures along a Knudsen pump and observed differences in flow of the individual components of the mixture. T Baier, E Bick, C Wetterich. Latest supplement. Link: https://doi.org/10.1017/jfm.2019.921. DOI: 10.1103/PhysRevApplied.13.014015. Electronic address: stark@pos.tu-darmstadt.de. Hide All. Steffen Hardt Professor, TU Darmstadt Verified email at nmf.tu-darmstadt.de. 1994 Molecular Gas Dynamics and the Direct Simulation of Gas Flows. We investigate the impact of insoluble surfactants on shear flow along a superhydrophobic surface in Cassie state, with gas trapped in grooves oriented perpendicular to the flow direction. Nanoscale gas kinetics, electrokinetics, interfacial flows, wetting phenomena and biomolecular separation belong to our areas of work. Click here for details, Species transfer using small droplets as carriers. 7 Physics of Surfaces, Technische Universität Darmstadt, Alarich-Weiss-Straße 16, 64287 Darmstadt, Germany. 5, Iss. If, however, small particles or surfactants are adsorbed to a gas-liquid or liquid-liquid interface, the interface itself becomes viscous. As a stream encounters an obstacle, floating debris sometimes piles up in front of the obstacle, forming a dense layer on the water surface. Supplemental Material (Subscription Required) Click to Expand. Upon touching the reservoir, the droplet reverses its charge and its direction of motion. Apart from its relevance in applications, this process goes along with the formation of characteristic DNA concentration patterns, visible in the figure at the left. Reference: P. Goswami, T. Baier, S. Tiwari, C. Lv, S. Hardt, and A. Klar, Drag force on spherical particle moving near a plane wall in highly rarefied gas. Dr. Naren Bag PhD, IIT Kharagpur Verified email at iitkgp.ac.in. T. Baier and S. Hardt, Influence of insoluble surfactants on shear flow over a surface in Cassie state at large Péclet numbers, Journal of Fluid Mechanics 907 (2020), A3. DOI: 10.1103/PhysRevLett.124.064501, Tutorium „CFD-based simulation and optimization of microfluidic components“, This tutorium will equip students with the basic methodology needed to design and optimize microfluidic components on the computer. Vol. † Email address for correspondence: hardt@nmf.tu-darmstadt.de. In that case, ring-like structures are formed from the film. Intermediate wetting states on superhydrophobic surfaces. Surface acoustic waves (SAW) are widely used in microfluidics for transporting and mixing liquids. With this in mind, we investigated the impact that surfactants have on this mechanism and found that parts of the gas-water interface become ‘solidified’ by surfactant pile-up. Human resources department, International office: neumann@nmf.tu-... +49 6151 16-24277. These liquid rings finally collapse and form plugs that are propelled along the capillary tube by evaporation. Journal of Fluid Mechanics 883, 47 (2020). Stability and collapse of holes in liquid layers - Volume 855 - Cunjing Lv, Michael Eigenbrod, Steffen Hardt Markus Biesalski Professor für Makromolekulare Chemie und Papierchemie, Technische Universität Darmstadt Verified email at cellulose.tu-darmstadt.de. These liquid rings finally collapse and form plugs that are propelled along the capillary tube by evaporation. 82-85, Proc. Bird, G. A. Reference: M. Shojaeian and S. Hardt, Mass transfer via femtoliter droplets in ping-pong mode, Physical Review Applied 13 (2020), 014015. A summary of the main results can be found here. ‡ Corresponding author: hardt@nmf.tu-darmstadt.de; Article Text (Subscription Required) Click to Expand. Below, the same research outputs are grouped by subject. Hirofumi Shintaku RIKEN Hakubi Team Leader Verified email at me.kyoto-u.ac.jp. The method is sketched in the schematic on the left. Click here for details, Species transfer using small droplets as carriers. Steffen Hardt Professor, TU Darmstadt Verified email at nmf.tu-darmstadt.de. Usually, viscosity is a quantity associated with the bulk of a fluid. Flow and streaming potential of an electrolyte in a channel with an axial temperature gradient - Volume 813 - Mathias Dietzel, Steffen Hardt “Tears of wine” is a phenomenon that can be observed in wine glasses: Driven by Marangoni stresses, a liquid film crawls up along the glass wall. We have studied the transport of gas mixtures along a Knudsen pump and observed differences in flow of the individual components of the mixture. Return to institution outputs. L2|06 113. B. Rofman, S. Dehe, V. Frumkin, S. Hardt, and M. Bercovici, Intermediate states of wetting on hierarchical superhydrophobic surfaces, Langmuir 36 (2020), 5517−5523. Tobias Baier Center of Smart Interfaces, TU Darmstadt Verified email at nmf.tu-darmstadt.de. We have found a solution to this problem, where a droplet with a diameter of the order of 5 µm serves as carrier for the cargo. A: Alarich-Weiss-Straße 10, L2|06 111, 64287 Darmstadt, GER T: +49 6151 16-24276. Surfactants can immobilize fluid–liquid interfaces under shear stress. Institut für Druckmaschinen und Druckverfahren, TU Darmstadt Germany . M. Dietzel and S. Hardt, Electroosmotic flow in small-scale channels induced by surface-acoustic waves, Physical Review Fluids 5 (2020), 123702. Philippe Bourrianne Princeton Verified email at princeton.edu. Title. Knudsen pumps rely on gas-flows induced by temperature differences. Usually, viscosity is a quantity associated with the bulk of a fluid. Administrative Staff Corinna Neumann. pp. References (Subscription Required) Click to Expand. Anal. Klingenberg, Dario ; Oberlack, Martin ; Pluemacher, Dominik (2020): Symmetries and turbulence modeling. 5 — May 2020. Microfluid Nanofluid 24, 41 (2020). 26 (1), 45 – 65. The course language will be English. Head of Institute. M. Eigenbrod and S. Hardt, The effective shear and dilatational viscosities of a particle-laden interface in the dilute limit, Journal of Fluid Mechanics 903 (2020), A26. M. Eigenbrod and S. Hardt, The effective shear and dilatational viscosities of a particle-laden interface in the dilute limit, Journal of Fluid Mechanics 903 (2020), A26. The course language will be English. DOI: 10.1017/jfm.2020.80, Pattern formation in layers of DNA molecules. The table to the right includes counts of all research outputs for Technical University of Darmstadt (TU Darmstadt) published between 1 September 2019 - 31 August 2020 which are tracked by the Nature Index. DNA molecules can be concentrated by electrophoretic accumulation at an interface between two immiscible polymer solutions. Office. Issue. DOI: 10.1103/PhysRevLett.124.064501, Tutorium „CFD-based simulation and optimization of microfluidic components“, This tutorium will equip students with the basic methodology needed to design and optimize microfluidic components on the computer. We have studied the transfer of chemical species between the two reservoirs mediated by the droplet. Up to now, the electrokinetic effects due to SAWs have remained largely unexplored. Mikrosystemtechnik Kongress 2011, Darmstadt, Germany, [Conference or Workshop Item] Hahn, T. (2011): Interfacial electrokinetic transport phenomena and their impact on DNA electrophoresis in microfluidics. Tobias Baier Center of Smart Interfaces, TU Darmstadt Verified email at nmf.tu-darmstadt.de. Picture: NMF. Babovsky, H. & Illner, R. 1989 A convergence proof for Nanbu’s simulation method for the full Boltzmann equation. Nano- and Microfluidics You are here: TU Darmstadt; Maschinenbau; Nano- and Microfluidics; Sitemap. Duval CNRS Research Director - LIEC Laboratory (Nancy, France) Verified email at univ-lorraine.fr. https://doi.org/10.1007/s10404-020-02342-6. We find a multitude of intermediate states between the classical Cassie and Wenzel states. The droplet reciprocates between two aqueous reservoirs under the influence of a DC electric field. Via the charges created at the gas-liquid interfaces, the flow velocity can be increased by more than a factor of 10 compared to unstructured surfaces. Microfluid Nanofluid 24, 41 (2020). Unsere Forschung erstreckt sich über ein breites Themenspektrum und kombiniert experimentelle, theoretische und numerische Ansätze. Artificial intelligence is one of the most rapidly advancing and controversial topics in scientific research. For a small particle inside a gas, the fluid dynamics of such problems becomes very involved, since the Navier-Stokes equation is no longer applicable. Reuse & Permissions . Jérôme F.L. No articles found. We have recently derived analytical expressions for the viscosity coefficients of a particle-laden fluid interface in the limit of low particle concentrations. We have recently derived analytical expressions for the viscosity coefficients of a particle-laden fluid interface in the limit of low particle concentrations. We have computed the corresponding drag force on a particle and find that it is much lower than the one predicted by the Navier-Stokes equation. A summary of the main results can be found here. Nature Index 2020 Artificial Intelligence. Transferring chemical species or nanoparticles in a controlled way becomes challenging when very small species amounts are considered. The transition from the Cassie state to these intermediate states is partially reversible. Therefore, SAW-induced EOF may be useful as a method for pumping liquids through small scale channels. We have studied this phenomenon based on experiments and theory. These results could significantly simplify simulations of two-phase flows with particle-laden interfaces. Institute of Applied Geosciences (IAG), TU Darmstadt . Our research extends over a broad thematic spectrum and combines experimental, theoretical and numerical approaches. Reference: C. Lv, S. N. Varanakkottu, and S. Hardt, Liquid plug formation from heated binary mixtures in capillary tubes, Journal of Fluid Mechanics 889 (2020), A15. Institute for Nano- and Microfluidics, TU Darmstadt, 64287 Darmstadt, Germany * hardt@nmf.tu-darmstadt.de; Article Text (Subscription Required) Click to Expand. Herzlich willkommen am Fachgebiet Nano- und Mikrofluidik. 6 Intitut für Angewandte Geowissenschaften, Technische Universität Darmstadt, Schnittspahnstraße 9, 64287 Darmstadt, Germany. Sort by citations Sort by year Sort by title. References. Working area(s) Emeritus. In addition, the flow is entirely pH-independent. Reference: P. Goswami, T. Baier, S. Tiwari, C. Lv, S. Hardt, and A. Klar, Drag force on spherical particle moving near a plane wall in highly rarefied gas. Следене. Apart from its relevance in applications, this process goes along with the formation of characteristic DNA concentration patterns, visible in the figure at the left. Nano- and Microfluidics Welcome to the Institute for Nano- und Microfluidics. Unsere Forschung erstreckt sich über ein breites Themenspektrum und kombiniert experimentelle, theoretische und numerische Ansätze. Steffen Hardt Professor, TU Darmstadt Verified email at nmf.tu-darmstadt.de. www.nmf.tu-darmstadt.de. If, however, small particles or surfactants are adsorbed to a gas-liquid or liquid-liquid interface, the interface itself becomes viscous. L2|06 112. About TU Darmstadt – The Technical University (TU) of Darmstadt is one of Germany’s leading technical universities. A summary of the main results can be found here.