• Title/Summary/Keyword: Discharge

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A study on the dominant discharge in small and medium-sized stream (Yo-Stream) (중소하천(요천)에서 지배유량 연구)

  • Rim, Chang-Soo;Lee, Joon-Ho
    • Korean Journal of Agricultural Science
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    • v.38 no.2
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    • pp.309-314
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    • 2011
  • The purpose of this study is to select the dominant discharge which mostly affects the formation of the channel shape in Yo-Stream. So far, three different discharge conditions such as bankfull discharge, discharge of a specific recurrence interval, and effective discharge have been considered as an indicator of dominant discharge. Therefore, three different discharge conditions were studied and based on the study results, dominant discharge was selected for Yo-Stream. When comparing bankfull discharge and effective discharge at Beonam stream gaging station, it has turned out that effective discharge was 10 $m^3$/sec, which is 6 times greater than bankfull discharge of 58.83 $m^3$/sec. Furthermore, when comparing bankfull discharge and discharge of a specific recurrence interval, bankfull discharge was quite similar to discharge with recurrence interval of 1.52 years. Previous study results also indicate that dominant discharge occurs with recurrence interval of similar duration. Therefore, discharge of 58.83 $m^3$/sec was considered as a dominant discharge, which corresponds to discharge with recurrence interval of 1.52 years.

A study on the arc discharge characteristics of liquid insulating materials for electrical discharge machine (방전가공기용 액체 절연재료의 아크 방전 특성 연구)

  • 김상현;김해종;마대영;신태민
    • Electrical & Electronic Materials
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    • v.8 no.5
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    • pp.564-571
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    • 1995
  • This paper deals with the arc discharge characteristics of kerosene oil as a basic study on electrical discharge machine. Using needle electrode the discharge voltage, discharge current, discharge energy and the shape of discharge crater are measured. In consequence, it becomes clear that the discharge crater(depth, height, diameter) is depending on the discharge energy. Rapid increase in depth, height and diameter of discharge crater was observed during initial discharge, where discharge energy is large. However, rather slow decrease of those values was found when discharge energy is low or N is more than 3. As the ratio of $I_p$$T_on$ increase, the shape of discharge crater gets near circle. The protuberances of the discharge crater were not formed by the melted needle electrode but by the that of work piece.

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A Study on the New Discharge AND Gate and Drive Scheme for the Cost Down of the PDPs (PDP의 가격절감을 위한 새로운 방전 AND Gate 및 구동기술에 관한 연구)

  • 염정덕
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.6
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    • pp.267-273
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    • 2003
  • The plasma display panel with the electrode structure of new discharge AND gate and its driving scheme were proposed and the driving system for experiment was developed. And operation of these discharge AND gate was verified by the experiment of PDP addressing with floating electrode. This discharge AND gate operated by the operation speed of 8$mutextrm{s}$ and the operation margin of 100V. The address operation margin of 10V also obtained. It was known to be able to control the discharge of the adjoining scan electrode accurately. Because proposed method uses the DC discharge the control of the discharge can be facilitated compared with conventional discharge AND gate. Moreover, because the input discharge and the output discharge of discharge gate are separate, the display discharge can be prevented from passing discharge gates. Therefore, it is possible to apply to the large screen plasma display panel. And the decrease of contrast ratio does not occur because the scanning discharge does not influence the picture quality.

A Study on Minimum Ignition Energy by Controlled Discharge Energy (방전에너지 제어에 의한 최소점화에너지의 고찰)

  • Choi, Sang-Won;Ohsawa, Atsushi
    • Journal of the Korean Society of Safety
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    • v.22 no.1
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    • pp.36-39
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    • 2007
  • It is important to know Minimum Ignition Energy(MIE) of flammable materials for ignition hazard of chemical processes etc.. Currently a capacitor discharge is used mainly to measure the MIE. Then, it is impossible to control actively discharge energies and discharge time because the MIE measurement uses a high voltage capacitor and fixed capacitor. However, the control of discharge energy and discharge time will be convenient if self-sustain discharge is used. In this paper, we measured the MIE by self-sustain discharge of a pulse shape to propose the new measuring method of the MIE. AS a result, ignition energies are increased gradually as discharge duration time gets longer, and discharge current grows larger. Also, an arc discharge and a glow discharge occurred during the experimental period, and the ignition by glow discharges happened when discharge duration time was $90{\mu}s$, discharge current was 8A and 1A Especially, the MIE occurred the 0.05mm and 0.08mm of the gap distance between discharge electrode in the same discharge duration time.

The Effect of Rotation of Discharge Hole on the Discharge Coefficient and Pressure Coefficient (송출공의 회전이 송출계수와 압력계수에 미치는 영향)

  • Ha, Kyoung-Pyo;Ku, Nam-Hee;Kauh, S.Ken
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.7
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    • pp.948-955
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    • 2003
  • Pressure coefficient in rotating discharge hole was measured to gain insight into the influence of rotation to the discharge characteristics of rotating discharge hole. Pressure measurements were done by the telemetry system that had been developed by the authors. The telemetry system measures static pressure using piezoresistive pressure sensors. Pressure coefficients in rotating discharge hole were measured in longitudinal direction and circumferential direction with various rotating speed and 3 pressure ratios. From the results, the pressure coefficient, and therefore the discharge coefficient, is known to decrease with the increase of Ro number owing to the increase of flow approaching angle to the discharge hole inlet. However, there exists critical Ro number where the decrease rate of discharge coefficient with the increase of Ro number changes abruptly; flow separation occurs from the discharge hole exit at this critical Ro number. Critical Ro number increases with the increase of length-to-diameter ratio, but the increase is small where the length-to-diameter ratio is higher than 3. The decrease rate of discharge coefficient with the increase of Ro number depends on the pressure recovery at the discharge hole, and the rate is different from each length-to-diameter ratio; it has tendency that the short discharge hole shows higher decrease rate of discharge coefficient.

Assessment of Flood Frequency of Bankfull Discharge in Korea Rivers (국내 하천 강턱유량시의 홍수빈도 추정)

  • Son, Min-Woo;Lee, Du-Han;Kim, Chang-Wan;Kim, Myoung-Hwan
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1571-1575
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    • 2006
  • Channel form discharge which determines shape and character of a channel is named as dominant discharge. Assuming that fixed discharge flows in the fluvial plain for a long time, it is channel form discharge of a certain channel if it changes the fluvial plain into shape of the channel. Channel form discharge can be demonstrated by concept of bankfull or effective discharge. 1.01, 1.58, 2, 2.33 and 5 year flood discharge were used in order to determine channel form discharge. Each frequency discharge was determined by 80 year flood discharge by a research result conducted by Kim and Won. 1.01 year frequency discharge was selected as the most similar discharge to bankfull discharge. 1.58 year frequency discharge habitually used in Korea exceeded bankfull discharge.

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Assessment of Flood Frequency of Bankfull Discharge in Korea Rivers (국내 하천 강턱유량시의 홍수빈도 추정)

  • Son, Min-Woo;Lee, Du-Han;Kim, Chang-Wan;Kim, Myoung-Hwan
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1107-1111
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    • 2006
  • Channel form discharge which determines shape and character of a channel is named as dominant discharge. Assuming that fixed discharge flows in the fluvial plain for a long time, it is channel form discharge of a certain channel if it changes the fluvial plain into shape of the channel. Channel form discharge can be demonstrated by concept of bankfull or effective discharge. 1.01, 1.58, 2, 2.33 and 5 year flood discharge were used in order to determine channel form discharge. Each frequency discharge was determined by 80 year flood discharge by a research result conducted by Kim and Won. 1.01 year frequency discharge was selected as the most similar discharge to bankfull discharge. 1.58 year frequency discharge habitually used in Korea exceeded bankfull discharge.

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Estimation of Maintenance Flow for Suitable Utilization of Fishway (어도의 적절한 이용을 위한 유지유량 평가)

  • Kim, Seok-gyu;Kim, Chul;Kim, Seonghwan;Ko, Kwangyong
    • Journal of Korean Society on Water Environment
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    • v.25 no.2
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    • pp.281-287
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    • 2009
  • Achieved monitoring regularly about fishway that is a intake dam belongings to Kyeongchon for 5 years. Result that achieve monitoring, discovered pressing issue of opening and closing degree of discharge control part in fishway. In this research, analyze discharge relation with fishway and intake sluice and presented operation plan of opening and closing of discharge control part. Investigated necessity intake discharge and benefited area to analyze relation of discharge that is flowed in fishway and discharge escaping by intake sluice. When opened discharge control part step by step gradually, analyzed discharge. Compared with survey discharge making ration curve of fishway and intake sluice using orifice and submerged weir formula. Because operation of intake dam is necessary intake discharge and upriver inflow discharge by time, operation uses by survey discharge and calculated opening discharge of fishway by opening discharge of intake sluice via monthly inflow discharge. To sum up, calculated floodgate opening height of fishway by water level to present maintenance standard of intake dam.

Analysis on Partial Discharge Fault Signals of PRPD for High Voltage Motor Stator Winding (고압전동기 고정자 권선의 PRPD 부분방전 결함신호 해석)

  • Park Jae-Jun;Lee Sung-Young;Mun Dae-Chul
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.19 no.10
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    • pp.942-946
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    • 2006
  • We simulated insulation defects of stator winding wire on high voltage generator by 5 types. 4 types have one discharge source and other one has multi discharge source by simulation. For accurate decision, measurements used to PRPD pattern to occurred partial discharge source of various types. In this research, when PRPD pattern carried out or analyzed pattern recognition of discharge source, it used to powerful tools. In this result, PRPD Pattern defined to have single discharge source of 4 types by insulation defect. When insulation defect simulated, all the defected winding have not the same result. Errors for a little different can make mistakes from a subtle distinction. The difference between internal and void discharge have magnitude of pulse amplitude of inner discharge bigger than void discharge and have a shape of bisymmetry. But void discharge has a shape of bisymmetry against maximum value on polarity respectively. In cases of slot and surface discharge, we confirmed to show similar results those other researchers. In case of multi-discharge, as a result of we could classify not perfect match with occurred patterns in single discharge eachother. In the future, we will have to recognize and classify with results of multi-discharge.

Effect of Discharge Gas on the Electrical Characteristics of the Glow Discharge Plasma for the Gas Chromatographic Detector (글로우방전 가스크로마토그라프 검출기에서 방전가스의 영향)

  • 박현미;강종성;김효진
    • YAKHAK HOEJI
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    • v.39 no.5
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    • pp.480-486
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    • 1995
  • The change in discharge current of a glow discharge has been shown the potential sensitive detector for gas chromatography. To investigate the effect of carrier gas on the electrical characteristics of the discharge and the peak response, the discharge pressure, gas flow rate, and discharge gap have been studied. The discharge gas included the Ar, He, and N$_{2}$. The gas flow rate has been found one of the important parameters to affect both the electrical characteristics and the peak response.

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