• Title/Summary/Keyword: Arc Pressure

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Analysis of reactive species in water activated by plasma and application to seed germination

  • Choi, Ki-Hong;Lee, Han-Ju;Park, Gyungsoon;Choi, Eun-Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.162.1-162.1
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    • 2015
  • The use of plasma has increased in bio-application field in recent years. Particularly, water treated by arc discharge or atmospheric pressure plasma has been actively utilized in bio-industry. In this study, we have developed a plasma activated water generating system. For this system, two kinds of plasma sources; dielectric barrier discharge (DBD) plasma and arc discharge plasma have been used. The discharge energy was calculated using the breakdown voltage and current, and the emission spectrum was measured to investigate the generated reactive species. We also analyzed the amount of reactive oxygen and nitrogen species in water using the chemical methods and nitric oxide sensor. Finally, the influence of plasma generated reactive species on the germination and growth of spinach (Spinacia oleracea) was investigated. Spinach is a green leafy vegetable that contains a large amount of various physiologically active organic compounds. However, it is characterized with a low seed germination rate.

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Preparation of FeAl nanopowders by Plasma Arc Discharge Process (플라즈마 아크방전(PAD)법으로 제조된 FeAl 나노분말 특성)

  • Park Woo-Young;Youn Cheol-Su;Yu Ji-Hun;Oh Young-Woo;Choi Chul-Jin
    • Journal of Powder Materials
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    • v.11 no.6 s.47
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    • pp.522-527
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    • 2004
  • Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous $AI_{2}O_{3}\;and\;a\;little\;amount\;of\;metallic\;Fe_{3}O_{4}.$ Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.

RELATIONSHIP BETWEEN FABRIC SOUND PARAMETERS AND SUBJECTIVE SENSATION

  • Yi, Eunjou;Cho, Gilsoo
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2000.04a
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    • pp.138-143
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    • 2000
  • In order to investigate the relationship between fabric sound parameters and subjective sensation, each sound from 60 fabrics was recorded and analyzed by Fast Fourier transform. Level pressure of total sound (LPT), three coefficients (ARC, ARF, ARE) of auto regressive models, loudness (Z), and sharpness (Z) by Zwickers model were estimated as sound parameters. For subjective evaluation, seven sensation (softness, loudness, sharpness, clearness, roughness, highness, and pleasantness) was rated by both semantic differential scale (SDS) and free modulus magnitude estimation (FMME). As the results, the ARC values were positively proportional to both LPT and loudness (Z) values. In both of SDS and FMME, softness, clearness, and pleasantness were negatively correlated with loudness, sharpness, roughness, and highness. In regression models, softness and clearness by FMME were negatively affected by LPT뭉 ARC, while loudness, sharpness, roughness, and highness were positively expected. Regression models for pleasantness showed low values for R2.

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Effect of the Process Parameters on the Fe Nano Powder Formation in the Plasma Arc Discharge Process (플라즈마 아크 방전법에서 Fe 나노 분말 형성에 미치는 공정변수의 영향)

  • 이길근;김성규
    • Journal of Powder Materials
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    • v.10 no.1
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    • pp.51-56
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    • 2003
  • To investigate the effect of the parameters of the plasma arc discharge process on the particle formation and particle characteristics of the iron nano powder, the chamber pressure, input current and the hydrogen volume fraction in the powder synthesis atmosphere were changed. The particle size and phase structure of the synthesized iron powder were studied using the FE-SEM, FE-TEM and XRD. The synthesized iron powder particle had a core-shell structure composed of the crystalline $\alpha$-Fe in the core and the crystalline $Fe_3O_4$ in the shell. The powder generation rate and particle size mainly depended on the hydrogen volume fraction in the powder synthesis atmosphere. The particle size increased simultaneously with increasing the hydrogen volume fraction from 10% to 50%, and it ranged from about 45nm to 130 nm.

Psychoacoustic Characteristics of Fibers

  • Yi, Eunjou;Cho, Gilsoo
    • Fibers and Polymers
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    • v.1 no.1
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    • pp.59-65
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    • 2000
  • In order to investigate psychoacoustic characteristics of fibers, and to compare them with sound physical parameters, each sound of 25 different fabrics consisted of a single fiber such as wool, cotton, silk, polyester, and nylon was recorded. Sounds of specimens were transformed into critical band diagram and psychoacoustic characteristics including loudness and sharpness for each sound were calculated based on Zwicker's models. Physical parameters such as the level pressure of total sound (LPT), level ranges (ΔL), frequency differences (Δf), AR coefficients (ARC, ARF, ARE) were obtained in fast fourier transform (FFT) spectrum. Nylon taffeta showed higher values for loudness than 2.5 sone corresponding to human low conversation, while most silk fibers generated less louder showing lower values for loudness than 1.0 sone. Wool fibers had higher loudness mean value than that of cotton, while the two fibers didn't differ in LPT. Loudness showed high positive correlation coefficients with both LPT and ARC. Sharpness values were higher for wool fiber group than other fibers. Sharpness was not concerned with loudness, LPT, and ARC, but the fabrics with higher values for sharpness tended to show higher ΔL.

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Development of Medium Voltage $SF_6$ Interrupter for RMU ($SF_6$ 가스를 이용한 배전급 RMU용 소호부 개발)

  • Lee, B.W.;Sohn, J.M.;Seo, J.M.;Choe, J.W.
    • Proceedings of the KIEE Conference
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    • 2001.05a
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    • pp.301-304
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    • 2001
  • This paper considers the research of the hybrid interrupter which adopts both rotating arc and thermal expansion technology. The operating principle of this device defends on rapid arc rotation due to the magnetic field created by the fault current through a coil which is mounted on contacts and also relies on the principle of thermal expansion created by arc energy in extinguishing chamber and finally causes pressure rise in expansion volume. In this research, the principle of the interrupting techniques are given and experimental results of hybrid interrupter which is developed by new technology is introduced.

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NUMERICAL ANALYSIS OF A 150KW HUELS TYPE ARC HEATER (150kW급 Huels형 아크 히터 내부의 유동 해석)

  • Han, S.H.;Byeon, J.Y.;Kim, K.H.
    • 한국전산유체공학회:학술대회논문집
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    • 2010.05a
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    • pp.562-566
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    • 2010
  • Numerical analysis of 150kW Huels-type arc jet was performed using compressible Navier-Stokes CFD code. To consider chemical reaction by high temperature, the flow was assumed to be chemical equilibrium states. As a turbulence and a radiation model, the two-equation k-epsilon model and the 3-band radiation model were adopted, respectively. Mass flow rate and current density were given as conditions for calculations. In this study, two kinds of mechanisms for injection of air flow wire considered. One is that air is provided by left wall surface and the other is that air is injected from upper wall surface. The pressure, density and temperature contours of two cases were compared and heat transfer rates were estimated. The numerical results of two cases were not much different to each other. However, in real 150KW device, air is injected from upper wall surface with swirl. To calculate more accurately, swirl effect is must be considered.

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On the Design Parameters of Gerotor Hydraulic Motors (제로터 유압 모터의 설계 변수에 관한 연구)

  • 김충현;김두인;안효석;정태형;이성철
    • Tribology and Lubricants
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    • v.15 no.1
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    • pp.17-23
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    • 1999
  • A Gerotor hydraulic motor is a planar mechanism consisting of a pair of rotors one of which encloses another rotor. The motion of the inner-rotor relative to the outer-rotor is produced by the pressure difference between the adjacent chambers. A design method of inner-rotor tooth profile using unit tangential vectors is presented in this work. Based on the relationships derived, the influence of the eccentricity of inner-rotor and the radius of circular arc tooth on the flow rate, torque and curvatures were investigated. It was shown that the flow rate and mean torque is proportional to eccentricity, but inversely proportional to the radius of circular arc teeth. Also, the maximum value of the equivalent curvature is increased as the eccentricity and the radius of circular arc teeth increased.

Prediction of Performance considering Ablated PTFE in High Voltage Self-blast Circuit Breaker (PTFE 용삭을 고려한 초고압 복합소호 차단기의 성능 예측)

  • Kim, Jin-Bum;Kweon, Ki-Yeoung;Lee, Hahk-Sung
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.695-698
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    • 2008
  • Self-blast circuit breakers utilize the energy dissipated by the arc itself to create the required conditions for arc quenching during the current zero. During the arcing period, high pressure, temperature and radiation of the arc could burn in pure SF6 gas and PTFE nozzle. Ablated nozzle shape and $SF_6$-PTFE mixture vapor affect the performance of an self-blast circuit breaker. After a number of tests, nozzle in circuit breaker is disassembled, a section of ablated nozzle is investigated precisely. Using computational fluid dynamics, the conservation equation for the gas and temperature, velocity and electric fields within breaker is solved. Before applying a section model, developed program is verified with experimental data. Performance of ablated nozzle shape is compared with original model through analysis program.

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A Study on the Application of Vortex Panel Method to 2 - D Turbo - machinery (2차원 터보기계에서의 와류패널법 적용에 관한 연구)

  • 최민선;김춘식;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • v.17 no.2
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    • pp.44-51
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    • 1993
  • Here is represented a vortex panel method to evaluate the performance characteristics of the 2-dimensional turbomachinery with circular arc blades or logarithmic blades. The present method is characterized by distributing small consecutive panels of linearly varing vortex strength satisfying boundary condition at control points and Kutta condition at trailing edge. To confirm the reliability of the present method, experimental result of a 2-D pump impeller of six circular arc blades is compared with the calculated one. As an application of the present method, figures are presented in series showing velocity and pressure distribution between blades.

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