scholarly journals Electric discharge during electrosurgery

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Alexey Shashurin ◽  
David Scott ◽  
Taisen Zhuang ◽  
Jerome Canady ◽  
Isak I. Beilis ◽  
...  
Keyword(s):  
Electric Discharge ◽  
Rayleigh Scattering ◽  
Positive Column ◽  
Plasma Electron ◽  
Atmospheric Plasma ◽  
Plasma Parameters ◽  
Breakdown Threshold ◽  
Half Wave ◽  
Electrical Conductivities ◽  
The Moment

Abstract Electric discharge utilized for electrosurgery is studied by means of a recently developed method for the diagnostics of small-size atmospheric plasma objects based on Rayleigh scattering of microwaves on the plasma volume. Evolution of the plasma parameters in the near-electrode sheaths and in the positive column is measured and analyzed. It is found that the electrosurgical system produces a glow discharge of alternating current with strongly contracted positive column with current densities reaching 103 A/cm2. The plasma electron density and electrical conductivities in the channel were found be 1016 cm−3 and (1-2) Ohm−1cm−1, respectively. The discharge interrupts every instance when the discharge-driving AC voltage crosses zero and re-ignites again every next half-wave at the moment when the instant voltage exceeds the breakdown threshold.

Alumina-Titania Spot Spraying Bead Formation and Characteristics in Atmospheric Plasma Spraying

2007 ◽  
Vol 534-536 ◽  
pp. 401-404
Author(s):  
Hye Sook Joo ◽  
Han Shin Choi ◽  
Hyung Ho Jo ◽  
Hoon Cho ◽  
June Seob Kim ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Mass Flux ◽  
Deposition Efficiency ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Gas Composition ◽  
Particle Segregation ◽  
Rate Maximum ◽  
The Moment ◽  
Short Time

Fine and coarse alumina-titania composite particles were overlaid by allowing the particles to be deposited for a short time without moving a plasmatron [spot spraying bead]. Both the deposition efficiency and maximum deposition rate were measured at the different plasma gas composition. Considering the normalized maximum deposition rate [(maximum deposition rate)x(deposition efficiency)-1], effects of particle size and plasma gas composition on the particle segregation within a cross-section of mass flux could be estimated. Also, particle melting state according to the position within a mass flux at the moment of impact could be also estimated through the investigations of microstructure and phase composition of the spot spraying bead.

scholarly journals Optical Emission Spectroscopic Analysis of Plasma Parameters in Cadmium by Nd: YAG laser Technique

2021 ◽  
Vol 2114 (1) ◽  
pp. 012049
Author(s):  
Uday H. Tawfeeq ◽  
Ahmed K. Abbas ◽  
Kadhim A. Aadim
Keyword(s):  
Laser Pulse ◽  
Atmospheric Pressure ◽  
Spectroscopic Analysis ◽  
Debye Length ◽  
Optical Emission ◽  
Plasma Electron ◽  
Laser Technique ◽  
Plasma Parameters ◽  
Yag Laser ◽  
Emission Spectroscopic Analysis

Abstract In this work, optical emission spectroscopy (OES) was used to estimate the parameters of plasma electron temperature (Te), electron density (ne), plasma frequency (fp), Debye length (λD), and Debye number (ND). Understanding how an energy pulsed laser affects these variables is also important. Irradiation of pure cadmium using an Nd: YAG laser pulse with a wavelength(1064)nm and energy ranging from (200-600)millijoules, of frequency (6) Hz. The spectrum of laser-induced plasma was detected under atmospheric pressure. It was discovered that when the energy of the laser pulse rises, the intensity of the CdI and CdII lines increases.

The effect of molecular ions on the plasma parameters in a medium pressure rare gas radio frequency discharge positive column

1992 ◽  
Vol 72 (7) ◽  
pp. 2632-2637 ◽  
Author(s):  
Jen‐Shih Chang ◽  
Y. Ichikawa ◽  
R. M. Hobson ◽  
S. Matsumura ◽  
S. Teii
Keyword(s):  
Radio Frequency ◽  
Positive Column ◽  
Molecular Ions ◽  
Rare Gas ◽  
Plasma Parameters ◽  
Medium Pressure ◽  
Radio Frequency Discharge

Study on the Methodology of Detection for Transformer Winding Insulation Defects Based on Impulse Test

2013 ◽  
Vol 805-806 ◽  
pp. 863-866
Author(s):  
Yu Sheng Quan ◽  
Dai Juan Wang ◽  
Hua Gui Chen ◽  
Zong Cheng Zhang
Keyword(s):  
Ratio Method ◽  
Half Wave ◽  
Insulation Defect ◽  
Impulse Voltage ◽  
Transformer Winding ◽  
Lightning Impulse ◽  
Harmonic Voltage ◽  
Transient Voltage ◽  
The Moment ◽  
Winding Insulation

A methodology of diagnosing the winding insulation defect according to data of transient voltage and current from the impulse voltage test is put forward in this paper. Lightning impulse test for transformer is divided into half-wave and full-wave at the moment. According to the full voltage and reduced voltage at two pressure processes. The transient voltage and current from the impulse voltage test can be divided into Series of harmonics. The insulation defect is diagnosed by dividing impulse voltage and current into series of harmonic and structuring discriminant function according to the longitudinal ratio method and cross ratio method for the corresponding period of harmonic voltage and current. The methodology is also applicable to diagnose whether there are insulation damage in the windings those have passed the lightning impulse test.

scholarly journals Multiwall Carbon Nanotube Made Antenna At Terahertz Frequency Range

2019 ◽  
Vol 8 (10) ◽  
pp. 2454-2457 ◽  
Keyword(s):  
Gold Foil ◽  
Guided Wave ◽  
Multiwall Carbon Nanotube ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Thin Gold Film ◽  
Fixed Dimension ◽  
Half Wave ◽  
The Moment ◽  
Multiwall Carbon

Earlier the propagation capability of BCNTs (bunch carbon nanotubes) made antenna was studied in terahertz frequency vicinity and its fulfilments were correlated with conventionally used thin gold film antenna. Those experiments were performed on the half-wave ribbon aerial of BCNTs and then on thin gold foil antennas which were resonated from 1THz to 50THz frequency range. To calculate its radiation efficiency they use both Moment of the moment (MOM) and potential integral equation (MPIE) technique. The numerical simulated result tells us that the radiation capability of a BNCTs of density 104 (CNTs/um) antenna has typically become smaller than the capability of gold foil antenna. We have experimented with replacing BCNT by MWCNT made antenna and studied its result on the same frequency range. After examination, we found that the interband transitions hinder big problems in MWCNT. It also hinders the propagation of guided wave and gives spoiling effect basically in the achievement of a fixed dimension MWCNT when we used it as an antenna.

scholarly journals Interaction of Cold Atmospheric Argon and Helium Plasma Jets with Bio-Target with Grounded Substrate Beneath

2019 ◽  
Vol 9 (21) ◽  
pp. 4528 ◽  
Author(s):  
Irina Schweigert ◽  
Dmitry Zakrevsky ◽  
Pavel Gugin ◽  
Elena Yelak ◽  
Ekaterina Golubitskaya ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Gas Flow ◽  
Fluid Model ◽  
Plasma Jet ◽  
Plasma Jets ◽  
Atmospheric Plasma ◽  
Maximum Efficiency ◽  
Embryonic Cells ◽  
Plasma Parameters

The cold atmospheric pressure plasma jet interaction with the bio-target is studied in the plasma experiment, 2D fluid model simulations, and with MTT and iCELLigence assays of the viability of cancer cells. It is shown, for the first time, that the use of the grounded substrate under the media with cells considerably amplifies the effect of plasma cancer cell treatment in vitro. Plasma devices with cylindrical and plane geometries generating cold atmospheric plasma jets are developed and tested. The sequence of the streamers which forms the plasma jet is initiated with a voltage of 2.5–6.5 kV applied with the frequency 40 kHz. We suggest using the grounded substrate under the bio-target during the plasma jet treatment of cancer cells. The analysis of the measured plasma spectra and comparison of OH-line intensity for different voltages and gas flow rates allows us to find a range of optimal plasma parameters for the enhanced OH generation. The time-dependent viability is measured for human cell lines, A431 (skin carcinoma), HEK 293 (kidney embryonic cells), and A549 (human lung adenocarcinoma cells) after the plasma jet treatment. The results with cell-based experiments (direct treatment) performed with various plasma jet parameters confirm the maximum efficiency of the treatment with the optimal plasma parameters.

THE COMPOSITION OF THE POSITIVE COLUMN OF A HELIUM GLOW DISCHARGE AT INTERMEDIATE PRESSURES

1979 ◽  
Vol 40 (C7) ◽  
pp. C7-127-C7-128
Author(s):  
F. Dothan ◽  
Yu. M. Kagan
Keyword(s):  
Glow Discharge ◽  
Differential Equations ◽  
Positive Column ◽  
Molecular Ions ◽  
Time Change ◽  
The Other ◽  
System Of Differential Equations ◽  
Plasma Parameters ◽  
Electron Collisions

The concentration of atomic and molecular ions and metastables is investigated for the positive column of a helium glow discharge. Recently (1,2) the system of differential equations for the helium afterglow describing the time change of these plasma parameters was written and solved. In the stationary positive column we can neglect some processes which are importent in the afterglow. On the other side we must take into account processes of excitation and ionization by electron collisions which can be neglected in the afterglow.

Pecvd RF Discharge Models Review

1989 ◽  
Vol 165 ◽  
Author(s):  
Alan Garscadden
Keyword(s):  
Kinetic Models ◽  
Plasma Chemistry ◽  
Plasma Electron ◽  
Secondary Emission ◽  
Rf Discharge ◽  
Data Sets ◽  
Plasma Parameters ◽  
Rf Discharges ◽  
Ion Collisions ◽  
Boundary Interaction

AbstractThis paper presents a concise and subjective summary of the rapid progress that has been made in the understanding of the essential features of RF discharges. The paper concentrates on introducing the important concepts used in modeling the rf discharge. The discharges have been modeled from several distinctly different approaches. These include circuit, beamdiffusion, plasma fluid or continuum, and particle kinetic models. The treatments have their usefulness depending on the application. The circuit models give easily parameterized results, power deposition, and phase angles between voltage and current, however, they do not describe the important plasma chemistry and the source terms for deposition and etching. The newer continuum models efficiently give self-consistent plasma parameters for higher pressure discharges but synergistic ion and neutral interactions with surfaces are difficult to include. The particle kinetic models can include many effects without approximations, however they need extensive data sets and long computer run times. The coupling of improved diagnostics and the different theories has resulted in a convergence of their conclusions. There are four distinct energy-gain mechanisms in the RF discharge : a bulk plasma excitation; electron beam excitation resulting from secondary emission from ion collisions with the electrodes; wave-riding acceleration on the sheath oscillation (collisional: Kushner); and a noncollisional plasma electron-sheath boundary interaction (Godyak). The relative contributions are sensitive functions of the gas mixture, pressure, frequency and RF voltage.

scholarly journals Multimodal Nonlinear Microscopy for Therapy Monitoring of Cold Atmospheric Plasma Treatment

Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 564 ◽  
Author(s):  
Tobias Meyer ◽  
Hyeonsoo Bae ◽  
Sybille Hasse ◽  
Jörn Winter ◽  
Thomas von Woedtke ◽  
...  
Keyword(s):  
Second Harmonic ◽  
Therapy Monitoring ◽  
Spectroscopic Method ◽  
Atmospheric Plasma ◽  
Quality Level ◽  
Fluorescence Lifetime Imaging ◽  
Plasma Parameters ◽  
Cold Atmospheric Plasma ◽  
Label Free Detection ◽  
Induced Changes

Here we report on a non-linear spectroscopic method for visualization of cold atmospheric plasma (CAP)-induced changes in tissue for reaching a new quality level of CAP application in medicine via online monitoring of wound or cancer treatment. A combination of coherent anti-Stokes Raman scattering (CARS), two-photon fluorescence lifetime imaging (2P-FLIM) and second harmonic generation (SHG) microscopy has been used for non-invasive and label-free detection of CAP-induced changes on human skin and mucosa samples. By correlation with histochemical staining, the observed local increase in fluorescence could be assigned to melanin. CARS and SHG prove the integrity of the tissue structure, visualize tissue morphology and composition. The influence of plasma effects by variation of plasma parameters e.g., duration of treatment, gas composition and plasma source has been evaluated. Overall quantitative spectroscopic markers could be identified for a direct monitoring of CAP-treated tissue areas, which is very important for translating CAPs into clinical routine.

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