Bulletin of the American Physical Society
71st Annual Gaseous Electronics Conference
Volume 63, Number 10
Monday–Friday, November 5–9, 2018; Portland, Oregon
Session QR4: Plasma-liquid Interactions |
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Chair: Koichi Sasaki Hokkaido University, & Peter Bruggeman, University of Minnesota Room: Oregon Convention Center A107-A109 |
Thursday, November 8, 2018 2:00PM - 2:15PM |
QR4.00001: Cavitation conversion efficiency for plasma generation methods in water Xin Tang, Dylan Baldwin, Jack Erspamer, Kunpeng Wang, Christopher Campbell, David Staack Cavitation compression is an effective energy focusing process for plasma generation in liquids. The collapsing process of cavitation is so intense that gases inside the cavitation will enter high energy states with plasma generation accompanied by light and shock wave emission. Three different underwater plasma generation methods are demonstrated based on the effective cavitation conversion efficiency. Sonoluminescence converts diffuse acoustic energy into cavitation bubble. Electrically-induced (corona or spark gap setup) cavitation initiates as a luminescent singularity then expands and oscillates as a cavitation bubble. Unlike other two, the mechanically-induced cavitation, usually non-spherical, can be created by impulsive hydrodynamic flow. Volumetric effective radius is utilized to estimate the maximum cavitation potential energy and the cavitation conversion efficiency is evaluated as the ratio of the maximum cavitation potential energy (before first singularity of the collapsing cavitation) over the input energy. The results indicated that the mechanically-induced cavitation for plasma generation is the most efficient method and it will make high efficient processing systems feasible for a broad range of chemical and physical engineering applications. [Preview Abstract] |
Thursday, November 8, 2018 2:15PM - 2:30PM |
QR4.00002: Time-resolved imaging of streamer formation inside bubble submerged in liquid Janis Lai, John Foster Plasma-based liquid activation applications such as water purification rely heavily on optimizing production and transport of plasma-derived reactive species into liquid media. A 2-D plasma-in-liquid apparatus was used to study the plasma-liquid interface region and induced reactivity in aqueous solutions. In this work, ultra-high speed imaging (ns exposure time) is employed to time-resolve streamer formation and propagation along the interface, while particle image velocimetry (PIV) is used to map the plasma-induced fluid flow field, which gives insight into the plasma-induced forces at the interface. Varying liquid parameters such as conductivity and surface tension impact how streamers propagate along the interface, and thus alter induced chemistry and fluid flow at the interface. Understanding discharge properties and fluid flow field in various liquids can inform future technologies on optimization of plasma-induced reactivity in liquid media. [Preview Abstract] |
Thursday, November 8, 2018 2:30PM - 3:00PM |
QR4.00003: Plasma-liquid interactions: towards a quantitative description of reactivity transfer? Invited Speaker: Peter Bruggeman The interaction of atmospheric pressure plasmas with liquid is a complex multiphase phenomenon. The transfer of the highly reactive chemistry produced in the gas-phase plasma to the bulk liquid phase enables many applications, including, water treatment and decontamination. While both gas and liquid phase chemistry have been studied separately in considerable detail, quantitative studies directly linking gas phase with liquid phase reactivity have been limited to modeling and lack experimental validation. We developed an experimental setup that eliminates many challenges related to complex fluid dynamics and allows studying plasma-liquid interactions. The setup consists of a diffuse glow discharge with a bulk uniform density of reactive species. A gas flow guides individual liquid micro-droplets produced by an on-demand droplet system through the plasma. This system allows the measurement of the gas phase reactive species densities and ex situ analysis of the collected droplets after plasma treatment. We will show preliminary results of the system that quantify the conversion of a model hydrocarbon compound in water. These results illustrate the capability of the setup to produce quantitative data on gas phase reactive species and liquid reactivity allowing validation of plasma-liquid interaction models.\\ \\In collaboration with: Gaku Oinuma, Advanced Technology R&D Center, Mitsubishi Electric Corporation, Japan; Gaurav Nayak, Department of Mechanical Engineering, University of Minnesota, USA. [Preview Abstract] |
Thursday, November 8, 2018 3:00PM - 3:15PM |
QR4.00004: Multiphysics Modeling of Plasma Discharge in Liquids: Simulation of Plasma Initiation Under Linear Ramp and Nanosecond Pulse Condition Ali Charchi Aghdam, Tanvir Farouk In this work, a mathematical model has been developed to simulate the initiation and propagation of plasma in a liquid medium. The model consists of a density based compressible momentum solver coupled with electric forces acting on the liquid. Electrostatic, polarization and electrostriction forces are considered. The Poisson's equation is solved to obtain the electric field distribution. Species conservation equations together with the associated plasma reaction kinetics are solved to resolve the spatial and temporal evolution of the charged species in the liquid medium. Simulations are conducted both for a linear ramp and nanosecond pulse of the driving voltage. The results show that the ponderomotive forces are dominant in the all of the cases studied. The polarization force becomes relevant at later times when a gradient in electric permittivity is developed. The negative pressure generated by the electric field is found to be below the critical value for water (\textasciitilde 30Mpa). Comparison between the linear ramp and nanosecond pulse further shows that under the nanosecond pulse condition a compression wave accompanies the expansion wave in the system. [Preview Abstract] |
Thursday, November 8, 2018 3:15PM - 3:30PM |
QR4.00005: Investigation Particle Emission from Surface of Electrolyte in a DC Atmospheric Pressure Glow with Liquid Anode Yao Kovach, John Foster Self-organization patterns observed on anode liquid surfaces in atmospheric pressure DC glow discharge represents both a mysterious and beautiful plasma physics phenomenon. The mechanisms underlying self-organization of plasmas in this context is still poorly understood. Recently, as observed with certain electrolytes under self-organization conditions, luminous particle emission from the liquid anode has been observed. High-speed camera analysis was used to map the 2D trajectories of these particles in order to analyze forces experienced by the particles during flight and to assess the initial launch velocity, which gives insight into the mechanism for launch. The composition and size range of the particles were analyzed by using a scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDX) diagnostics respectively. The particle temperature during its glowing trajectory was measured from an infrared (IR) camera as well. This work provides not only insight into injection particle dynamics but also the energetics associated with self-organization pattern formation. [Preview Abstract] |
Thursday, November 8, 2018 3:30PM - 3:45PM |
QR4.00006: Plasma-induced Phase Transition of Water Christopher Campbell, Xin Tang, Peng Xiao, Christopher Limbach, David Staack Nanosecond-pulsed plasma processes in gases and liquids can generate local high-pressure high-temperature regions via rapid energy deposition, which can lead to near-isochoric heating. This effect is enhanced for pulsed plasma processes in liquid media, due to high molecular density. For water plasmas, the presence of these high pressures (potentially in the gigapascal range) suggests that the surrounding water may be undergoing local phase transitions to Ice VI or Ice VII. Due to the transient localized nature of the process and the presence of high electric fields, these phase transitions cannot be modeled fully using conventional thermodynamic methods. A single-electrode water corona setup was used to experimentally investigate this phenomenon. By triggering this corona event with a well-timed nanosecond power supply, it is possible to time the corona event of interest relative to a high-energy Nd:YAG nanosecond laser pulse, such that temporally-resolved Raman spectroscopy is possible. Because of its sensitivity to water's vibrational energy structure, Raman spectroscopy can be employed in the aforementioned setup to identify different phases of water during the corona event. Raman spectra and accompanying shadowgraph imaging is presented and discussed. [Preview Abstract] |
Thursday, November 8, 2018 3:45PM - 4:00PM |
QR4.00007: Dynamics of mist emitted from Taylor cone with atmospheric corona discharge Fumiyoshi Tochikubo, Keisuke Nagao, Yusuke Nakagawa, Satoshi Uchida Plasma-liquid interaction is a hot topic in the application of atmospheric-pressure plasma. Use of mist will be the efficient method for plasma-liquid interaction because of its large specific surface area. There are many methods to generate plasma with mist. Atmospheric corona discharge using Taylor cone as a liquid electrode is interesting method for that purpose. We have reported the characteristics of atmospheric negative corona discharge using Taylor cone as a liquid cathode$^{(1)}$. In this work, we focus the mist emission from the Taylor cone synchronously with corona current. A micronozzle is filled with liquid, and a plate electrode is placed above the nozzle with 1cm gap. Sodium dodecyl sulfate is added in distilled water to control the surface tension. By applying a dc voltage between electrodes, a Taylor cone is formed on the micronozzle with Trichel pulse-like current. The vibration of tip of Taylor cone with roughly 20 kHz was observed by shadowgraph method with high speed camera. Synchronized with the vibration, droplets were emitted. Convection flow was observed in the Taylor cone. Mist dynamics were observed by Mie scattering. The velocity of charged droplet was approximately 10 m/s. (1) N. Shirai et al., Jpn. J. Appl. Phys. $\bf 53$ (2014) 026001. [Preview Abstract] |
Thursday, November 8, 2018 4:00PM - 4:30PM |
QR4.00008: Studies on selective production of RONS in the plasma-treated water and interaction between the plasma and amino acids Invited Speaker: Giichiro Uchida Atmospheric nonthermal plasma jets have been widely employed in biomedical applications because they induce slight thermal damage to biomaterials. Controlling the production of ROS and RNS in aqueous solutions is important in the plasma-jet system from the viewpoint of application because various cells are activated by ROS and RNS in an aqueous solution. In this study, we show experimental results on complicated interactions of the plasma with the aqueous solutions and the amino acids. First, we show development of a high-frequency plasma jet driven by voltages in the frequency range 6--60 MHz. The high-frequency plasma jet had a high O ($^{\mathrm{3}}$P) atom density of 8 × 10$^{\mathrm{14}}$ cm$^{\mathrm{-3}}$, and considerably contributed to the production of a large amount of RNS in aqueous solutions [1]. Secondly, we show selective production of the ROS and RNS in plasma-treated water [2]. Under the condition of plasma contact to the liquid surface, H$_{\mathrm{2}}$O$_{\mathrm{2}}$ was the more dominant species in the water, while for the plasma not contact condition, NO$_{\mathrm{2}}^{\mathrm{-}}$ was the more dominant species in the water. Thirdly, we show the basic study on the interaction between the plasma and amino acids, which is important for biomedical applications of plasmas. Our measurements showed that some amino acids are oxidized or decomposed upon plasma irradiation and that the strong effect of cancer-cell killing is induced by the plasma-treated amino-acid water. [1] G. Uchida, \textit{et al}., J. Appl. Phys. 122, 033301(2017). [2] G. Uchida, \textit{et al}., J. Appl. Phys. 120, 203302 (2016). [Preview Abstract] |
Thursday, November 8, 2018 4:30PM - 4:45PM |
QR4.00009: The competition between reduction and oxidation reactions in plasma electrolysis Hernan E. Delgado, Paul Rumbach, David M. Bartels, David B. Go One of the more common configurations for plasma electrochemistry consists of an electrolytic cell where the cathode or the anode is replaced by a direct current (DC) plasma in contact with the solution. By generating highly reactive species such as the hydroxyl radical (OH) and the solvated electron (e$^{\mathrm{-}}_{\mathrm{aq}})$, the plasma can initiate the oxidation and/or reduction of reactants in the liquid. This system has been used to study several applications including chemical synthesis, nanoparticle synthesis, and wastewater treatment. However, the competition between oxidizing and reducing reactions, as well as the creation of long-lived species that may continue to react even after the plasma is terminated, is not completely understood. Here, an electrolytic cell consisting of a DC low-temperature, atmospheric-pressure argon plasma and a submerged platinum counter electrode was used to study these chemical paths with ferricyanide, chloroacetate, and methylene blue model chemical systems. An analysis of competing reactions between reducing and oxidizing species and the effect of plasma polarity and pH, as well as the effects of transport limitation on the overall efficiency of the system are discussed. [Preview Abstract] |
Thursday, November 8, 2018 4:45PM - 5:00PM |
QR4.00010: Nanoporous gold thin film synthesis by plasma-assisted freeze templating: irradiation of cryoplasma onto frozen solution Noritaka Sakakibara, Tsuyohito Ito, Kazuo Terashima Plasma/liquid interfaces are now receiving increasing attention at wide range of applications. Here, we present a plasma-assisted freeze templating (PFT) method for materials processing, which uses a new type of plasma/liquid interface, i.e., plasma/ice interface. In PFT, micro- or nano-sized liquid layer that is formed on a frozen solution is used as a reaction field, in which chemical reactions are encouraged by reactive species from plasma. In this study, we have realized synthesis of nanoporous gold (NPG) self-supported thin film by PFT, only by irradiating helium cryoplasma jet onto frozen chloroauric acid solution. Auric solution was frozen to be concentrated in thin liquid layer on the ice surface, because auric ions are expelled from growing ice phase, on which cryoplasma was irradiated to reduce the auric ions. We can provide abundant reactivity of plasma without melting of the frozen solution, because the gas temperature in cryoplasma is controlled at cryogenic temperature [1]. PFT has accomplished surfactant-free, area-selective and one-step fabrication of NPG, that is more advantageous than conventional solution chemistry methods [2]. PFT is not only effective method for fabricating NPG thin films, but also expected as a novel technique for nano-engineering.” [1] N. Sakakibara and K. Terashima, J. Phys. D: Appl. Phys. \textbf{50} (2017) 22LT01. [2] M. Christiansen \textit{et al.,} J. Mater. Chem. A \textbf{6} (2018) 556. [Preview Abstract] |
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