• Title/Summary/Keyword: Field capacity

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Numerical Analysis on the Control of Particle-laden Flow Using Electromagnetic Field (전기자장에 의한 혼상류의 제어에 관한 수치해석)

  • NAM Seong-Won;KAMIYAMA Shin-icki
    • 한국전산유체공학회:학술대회논문집
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    • 1996.05a
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    • pp.125-130
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    • 1996
  • A numerical analysis is conducted on heat transfer and fluid flow of a plasma spraying process under the DC-RE hybrid electromagnetic field. Plasma flow is analyzed by using Eulerian approach and the equation of particle motion is simultaneously solved using a trajectory analysis with a lumped-heat-capacity model. Axisymmetric two dimensional electromagnetic fields governed by Maxwell's equations are solved based on a vector potential concept. The effects of the RF electromagnetic field on the temperature and velocity fields of the turbulent plasma flow are clarified. Control characteristics of phase changes and dispersed features of particles by applying the RF electromagnetic field are also clarified in an attempt to improve the plasma spraying process

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DEVELOPMENT OF SUPER WIDE SPREADER FOR DIRECT RICE SOWING IN WET PADDY FIELD

  • Kota Motobayashi;Yukio Yaji;Kim, Shoichi ura
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1996.06c
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    • pp.999-1008
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    • 1996
  • The development and improvement of the originally designed direct rice sowing machine were carried out for the specific purpose of saving labor and increasing the efficiency of field operations in rice cultivation in the northern part of Japan. the prototype super wide spreader has a unique mechanism which propels rice seeds by compressed air and spreads them from the pivoting nozzle while the machine is in motion. The effective field capacity of sowing operation is about 6 ha/h. This spreader can also handle granular chemicals such as fertilizers, herbicides, pesticides and insecticides.

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Electro-magnetic Field Analysis of 2-Layer HTS Power Transmission Cable Core (2층 고온초전도 전력케이블 코어의 전자장 해석)

  • 조전욱;주진홍;김석환;배준한;김해종;김해준;성기철;홍정표
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.269-271
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    • 2003
  • A typical HTS power transmission cable has multi-layer conductor structure to increase the current capacity. The tapes of the innermost layer are wound on a round former, and adjacent tapes of another layer are separated by a thin insulating film. In steady state, the total current flows in the conductor layer, and consequently there is magnetic field between the inner and outer layer. This paper describes a magnetic field amplitude around the conductor layer and the HTS tape by a transport current. Also, this paper will help for future cable conductor prototypes.

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The Vacuum Arc Analysis of Vl Applied Axial Magnetic Field (축자계형 진공차단기의 진공아크 해석)

  • Kang, Jin;Kim, Min-Soo;Choi, Seung-Kil;Ko, Kwang-Cheol;Kang, Hyung-Boo
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2221-2223
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    • 1999
  • Axial magnetic field($B_z$) generated by special electrode construction in vacuum interrupters(Vl) is used to extinguish electric plasma arcs because that restrains this form expending. So VI applied axial magnetic field has more interruption capacity as compared with other VI. Also, the profile of toroidal field($B_{\theta}$) generated by $B_z$, is important to VI design. In this study, it was represented that the behavior of vacuum arc. In addition, The relationship between $B_z$ and $B_{\theta}$ was represented by using Dynamo theory. I hope that this study will be a good data in design of vacuum interrupters.

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Development of a Wireless Control System for Rice Transplanter of Walking Type(II) -Field Test of the Experimental Machine- (보행(步行) 이앙기(移秧機)를 위(爲)한 무선자동제어(無線自動制御) 시스템의 개발(開發)(II) -공시기(供試機)의 포장실험(圃場實驗)-)

  • Kim, C.S.;Choi, K.H.;Min, Y.B.;Kim, S.T.
    • Journal of Biosystems Engineering
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    • v.17 no.3
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    • pp.213-222
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    • 1992
  • To develop the wireless remote opreating system of walking rice transplanter, this study was carried out for manufacturing the wireless remote control system acting upon the transplanter. The first report of this study contained about the construction and operating method of a developed remote control system for 2-row walking type transplanter. It is the second report about the field test for an experimental transplanter being attached a wireless control system and for a conventional transplanter. The test was executed to investigate the characteristics of velocity, rectilinearity, turning time, interval of roots and of rows, and field capacity in accordance with various engine speeds for an experimental transplanter. The measurements of this test were compared with those of the conventional transplanter. The obtained results were as follows : 1. The operating velocity of the experimental transplanter was faster than the conventional one when the high speed range of the engine but the variances were very large. 2. The rectilinearity, interval of raws and of roots, and the turning time of the experimental transplanter was inferior to the conventional one at some speed ranges of the engine. 3. Field capacity of the experimental transplanter was superior to the conventional one at high speed of the engine. 4. There were some disadvantages for the experimental transplanter to operate, because it was constructed without any aid devices, such as float and hydraulic system for instance. But if the remote control system of this study equip at the modern walking transplanter, it will be improved and utilized without defects which was revealed from this test.

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$^{137}Cs$ Concentrations in Cultivated Soils of Korea (우리나라 경작지 토양중 $^{137}Cs$ 농도)

  • Choi, Yong-Ho;Lim, Kwang-Muk;Lee, Myung-Ho;Park, Hyo-Guk;Lee, Won-Yun
    • Journal of Radiation Protection and Research
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    • v.24 no.2
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    • pp.55-63
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    • 1999
  • For understanding the radiation environment in the land of Korea and acquiring baseline data to be referred to at the time of a nuclear accident, cultivated soils in the $0{\sim}15cm$ layer were sampled at 33 sites scattered all over the country and $^{137}Cs$ concentrations were measured by $\gamma$-spectrometry. The soil $^{137}Cs$ concentrations were in the range of $0.7{\sim}17.7$ Bq/kg-dry in the paddy field and $1.2{\sim}27.8$ Bq/kg-dry in the upland field, The means were 6.9 Bq/kg-dry and 9.9 Bq/kg-dry, respectively. In the paddy field, the soil $^{137}Cs$ concentration was positively correlated to the organic matter content and negatively correlated to the clay content. In the upland field, it was positively correlated to the cation exchange capacity. It was revealed that soil organic matter play an important role in the change of soil $^{137}Cs$ concentration.

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Effects of Soil Moisture on Photosynthesis , Transpiration and Stomatal Resistance in sotghums II.Ondiurnal changes (토양수분이 수수류의 광합성 , 증산량 및 기공저항에 미치는 영향 II. 광합성과 증산량의 일중변화)

  • 한흥전;류종원
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.6 no.1
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    • pp.60-64
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    • 1986
  • To determine the effects of soil moisture on diurnal changes of photosynthesis, transpiration and stomatal resistance, sorghum and soghum-sudangrass hybrid were grown at large concrete pots maintained at 100, 80, 60 and 40% of field moisture capacity. Photosynthesis were measured from a.m. 6 to p.m. 6 on a fine day. 1. Photosynthesis and transpiration reacted similarly to water stress and environmental factors, and they reached at their maximum points from noon to 2 p.m. and decreased sharply after 4 p.m. 2. Photosynthesis and transpiration of sorghum were higher at 60% field moisture capacity than those of the other field moisture capacities. In sorghum-sudangrass hybrid, photosynthesis was in the order of 60>80>40>100% and transpiration was in the order of 60>80>100>40%. 3. Stomatal resistance did not show clear diurnal change and was the lowest at 60% among four field moisture capacities.

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Harvesting performance of an experimental pick-up type pulse crop harvester for green kernel black bean

  • Choi, Yeong Soo;Han, Byung Hee;Yoo, Soo Nam
    • Korean Journal of Agricultural Science
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    • v.44 no.1
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    • pp.114-122
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    • 2017
  • An experimental pick-up type pulse crop harvester was built and its harvesting performance for green kernel black bean was evaluated. Field bean loss and harvested bean quality of the harvester were analyzed according to engine speeds of 2,000; 2,400; 2,800; 3,000; and 3,200 rpm, and travel speeds of 0.6; 1.0; and 1.4 m/s. Operating conditions and field capacity of the harvester for proper harvesting were estimated. The harvester had an optimum performance at a grain moisture content of 13.4%, an engine speed of 3,000 rpm, and a travel speed of 1.2 - 1.3 m/s. Subsequently, the picking-up, discharging, and total bean loss ratios were found to be 1.6, 1.3, and 2.9%, respectively. The whole bean, damaged bean, unthreshed bean, and foreign material ratios were determined to be 96.2, 1.0, 0.1, and 0.3%, respectively. Results showed that the harvester had lower bean loss and higher harvested bean quality than those of imported bean combines. The harvester could harvest 2 rows with a crop spacing of an approximately 1.4 m. Its optimum travel speed was estimated to be approximately 1.2 m/s when harvesting performance was taken into account using such variables as field bean loss and harvested bean quality for green kernel black bean. Effective field capacity of the harvester was estimated at approximately 40 a/h.

Physiological studies on the sudden wilting of JAPONICA/INDICA crossed rice varieties in Korea -II. Artificial induction of sudden wilting in Korea and the effect of nutrio-physiological status (일(日)·인원연교잡(印遠緣交雜) 수도품종(水稻品種)의 급성위조증상(急性萎凋症狀) 발생(發生)에 관(關)한 영양생리학적(營養生理學的) 연구(硏究) -II. 한국(韓國)에서 급성위조증(急性萎凋症)의 인위적(人爲的) 재현(再現)과 영양생리(營養生理)의 영향(影響))

  • Kim, Yoo-Seob
    • Korean Journal of Soil Science and Fertilizer
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    • v.22 no.1
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    • pp.53-60
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    • 1989
  • The results of the investigation on the effects of plant nutrio-physiological status and reemergence of sudden wilting in rice on the occurrence of sudden wilting were summarized as follows: 1. The occurrence of sudden wilting, degree of damage and occurring time in the investigated variety showed to concur with the results of the previous experiment. 2. Nitrogen and Potassium contents in leaves related an occurrence of sudden wilting at heading stage have a very high negative co-relation (the value is -0.9224 at Yushin and -0.8243 at Milyang 23). 3. Regarding the relation between occurrence of sudden wilting and root activity capacity at the late growth stage, the root activity capacity at productive growth stage showed higher than at reproductive growth stage, which is the same in the two varieties but Milyang 23 is higher than Yushin. It is confirmed that root activity capacity in the two varieties has become very low at reproductive growth stage. 4. The toot activity capacity in the field with potassium showed a small occurrence of sudden wilting and the root activity capacity in the field with no potassium showed a very high co-relation value (the value is 0.8947 at Yushin and 0.7301 at Milyang 23). 5. Regarding the relation between the occurrence of sudden wilting and water evaporation quantity, water evaporation quantity after the heading date has a more direct relation to sudden wilting than that which occurrs prior to the heading date. Water evaporation quantity is higher in the field with no potassium, low leaves and Yushin, than in the field with potassium high leaves and Milyang 23. 6. The starch content in culm of Yushin and Milyang 23 at ripening stage showed high value in proportion to potassium quantity, and the starch content is lower as internode is lower. However, in fourth internode, the starch content is greatly increased in the field with potassium contrasted to the field with no potassium.

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A Study of the Characteristics on the Vacuum Interrupter with Axial Magnetic Field Type using 3 Dimension Finite Element Analysis (3차원 유한요소해석을 이용한 종자게형 진공 인터럽터의 특성고찰)

  • 하덕용;강형부
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.5
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    • pp.460-467
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    • 2002
  • This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.