Special Issue "Experiments in a Floating Water Bridge and Electrified Water"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydraulics and Hydrodynamics".

Deadline for manuscript submissions: 31 May 2021.

Special Issue Editors

Dr. Elmar C. Fuchs
E-Mail Website1 Website2 Website3
Guest Editor
1. Program Manager, Wetsus European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
2. Guest Researcher, Faculty of Science and Technology (TNW), Optical Sciences (OS), University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands
Interests: water; electrohydrodynamic liquid bridging; spectroscopy; proton conduction, the floating water bridge
Special Issues and Collections in MDPI journals
Dr. Astrid H. Paulitsch-Fuchs
E-Mail
Co-Guest Editor
Senior Lecturer for Biomedical analysis and Microbiology
Interests: fungi; aquatic microbiome; biofilms; electrohydrodynamic microbiology; microscopy
Prof. Dr. Jakob Woisetschläger
E-Mail Website
Co-Guest Editor
Institut for thermal Turbomachinery and Machine Dynamics, Graz University of Technology, Inffeldgasse 25/A, Austria
Interests: interferometry; vibrations; flow visualization; optical flow measurements; thermography; liquid bridges
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The interaction of polar liquids with moderately strong fields (kV/cm) has been studied extensively within the field of electrohydrodynamics (EHD). EHD liquid bridges like the floating water bridge have provided unique insights into the non-equilibrium molecular physics of polar liquids such as water. Whereas on the molecular scale water can be described by quantum mechanics, there is a conceptual gap at mesoscopic scale that is bridged by a number of theories including quantum mechanical entanglement and coherent structures in water. Much of the phenomenon is already understood, but even more can still be learned from it, since such “floating” liquid bridges resemble a small high-voltage laboratory of their own: the physics of liquids in electric fields of some kV/cm can be studied, even long-time experiments are feasible since the bridge is in a steady-state equilibrium and can be kept stable for hours. It is also an electro-chemical reactor where compounds are transported through by the EHD flow, enabling the study of electrochemical reactions under potentials which are otherwise not easily accessible. Last but not least, the bridge provides the experimental biologist with the opportunity to expose living organisms such as bacteria to electric fields and proton currents without killing them in order to study the influence of this special environment on their behavior and their genome.

This Special Issue will provide a broad platform for regular and review papers on the numerous up-to-date and multidisciplinary advances that are currently being achieved in the continuously growing area of liquid bridging and electrified liquids. Topics of interests include, but are not limited to:

  • Physico-chemical studies of electrohydrodynamic phenomena in general;
  • Molecular studies, spectroscopy, and simulation of liquids in strong electric fields;
  • Chemical reactions in strong electric fields and gradients;
  • Liquid mesoscale dynamics studies;
  • Microbiological and biochemical studies in electrohydrodynamic environments;
  • Neutron, X-ray, Raman, and Brillouin scattering studies of electrified liquids;
  • Microgravity studies of electrified liquids;
  • Infrared studies of electrified water;
  • NMR, MRI, and ESR studies of electrified liquids;
  • (Laser-)optical investigations and visualizations of electrohydrodynamic bridging and related phenomena.

It is our hope that a multidisciplinary collection of contributions will significantly accelerate the progress in this field due to the collaborative fostering of synergistic insights.

Dr. Elmar C. Fuchs
Prof. Dr. Jakob Woisetschläger
Dr. Astrid H. Paulitsch-Fuchs
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • electrohydrodynamic liquid bridge
  • floating water bridge
  • electrified water
  • proton conduction
  • water structure
  • electrified microorganisms

Published Papers (2 papers)

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Research

Open AccessArticle
Electrically Induced Liquid–Liquid Phase Transition in a Floating Water Bridge Identified by Refractive Index Variations
Water 2021, 13(5), 602; https://doi.org/10.3390/w13050602 - 25 Feb 2021
Viewed by 569
Abstract
A horizontal electrohydrodynamic (EHD) liquid bridge (also known as a “floating water bridge”) is a phenomenon that forms when high voltage DC (kV·cm−1) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts [...] Read more.
A horizontal electrohydrodynamic (EHD) liquid bridge (also known as a “floating water bridge”) is a phenomenon that forms when high voltage DC (kV·cm−1) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts as a cylindrical lens and refracts light. Using an interferometric set-up with a line pattern placed in the background of the bridge, the light passing through is split into a horizontally and a vertically polarized component which are both projected into the image space in front of the bridge with a small vertical offset (shear). Apart from a 100 Hz waviness due to a resonance effect between the power supply and vortical structures at the onset of the bridge, spikes with an increased refractive index moving through the bridge were observed. These spikes can be explained by an electrically induced liquid–liquid phase transition in which the vibrational modes of the water molecules couple coherently. Full article
(This article belongs to the Special Issue Experiments in a Floating Water Bridge and Electrified Water)
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Open AccessFeature PaperArticle
A Molecular-Level Picture of Electrospinning
Water 2020, 12(9), 2577; https://doi.org/10.3390/w12092577 - 15 Sep 2020
Viewed by 675
Abstract
Electrospinning is a modern and versatile method of producing nanofibers from polymer solutions or melts by the action of strong electric fields. The complex, multiscale nature of the process hinders its theoretical understanding, especially at the molecular level. The present article aims to [...] Read more.
Electrospinning is a modern and versatile method of producing nanofibers from polymer solutions or melts by the action of strong electric fields. The complex, multiscale nature of the process hinders its theoretical understanding, especially at the molecular level. The present article aims to contribute to the fundamental picture of the process by the molecular modeling of its nanoscale analogue and complements the picture by laboratory experiments at macroscale. Special attention is given to how the process is influenced by ions. Molecular dynamics (MD) is employed to model the time evolution of a nanodroplet of aqueous poly(ethylene glycol) (PEG) solution on a solid surface in a strong electric field. Two molecular weights of PEG are used, each in 12 aqueous solutions differing by the weight fraction of the polymer and the concentration of added NaCl. Various structural and dynamic quantities are monitored in production trajectories to characterize important features of the process and the effect of ions on it. Complementary experiments are carried out with macroscopic droplets of compositions similar to those used in MD. The behavior of droplets in a strong electric field is monitored using an oscilloscopic method and high-speed camera recording. Oscilloscopic records of voltage and current are used to determine the characteristic onset times of the instability of the meniscus as the times of the first discharge. The results of simulations indicate that, at the molecular level, the process is primarily driven by polarization forces and the role of ionic charge is only minor. Ions enhance the evaporation of solvent and the transport of polymer into the jet. Experimentally measured instability onset times weakly decrease with increasing ionic concentration in solutions with low polymer content. High-speed photography coupled with oscilloscopic measurement shows that the measured instability onset corresponds to the formation of a sharp tip of the Taylor cone. Molecular-scale and macroscopic views of the process are confronted, and challenges for their reconciliation are presented as a route to a true understanding of electrospinning. Full article
(This article belongs to the Special Issue Experiments in a Floating Water Bridge and Electrified Water)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

1. Title: Electrically induced liquid-liquid phase transition in a floating water bridge identified by refractive index variations
Authors: Elmar C. Fuchs, Giuseppe Vitiello, Adam. D. Wexler and Jakob Woisetschläger
Abstract: A horizontal electrohydrodynamic (EHD) liquid bridge (aka “floating water bridge”) is a phenomenon that forms when high voltage DC (kV/cm) is applied to pure water in two separate beakers. The bridge, a free-floating connection between the beakers, acts as a cylindrical lens and refracts light. Using a interferometric set-up line pattern placed in the background of the bridge is split into a horizontally and a vertically polarized component which are both into the image space in front of the bridge with a small vertical offset (shear). Apart from a 100Hz waviness due to a resonance effect between the power supply and vortical structures at the onset of the bridge, refractive index spikes move through the bridge. Both the spikes and the small anisotropy can be explained by an electrically induced liquid-liquid phase transition in which the vibrational modes of the water molecules couple coherently.

2. 1 paper from Authors: Antonella De Ninno <[email protected]> et al.

3. 1 paper from Authors: Giuseppe Vitiello <[email protected]> et al.

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