• Title/Summary/Keyword: Air influx rate

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Photosynthetic Response of Rice Plant to Changes of Air Influx Rate into Photosynthetic Chamber (동화상내 공기유입속도의 변화에 따른 벼의 광합성반응)

  • 현동윤;최경구;김진기
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.39 no.6
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    • pp.526-530
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    • 1994
  • This study was conducted to investigate photosynthetic response to four sequential air influx rate with rice(Oryza sativa L.)plants moved from a natural condition to constant condition with automatic regulation selected environmental variables on 13th~15th days after anthesis. In time course of photosynthetic response to increasing air influx rate(200-280-360-440 ml / min.), stomatal conductance decreased rapidly at the beginning after treatment and then oscillated with a free-running period of a approximately 1 hour to 1 hour 30 minutes until reached up to steady-state condition. Similar change was also observed $CO_2$ assimilation rate. Stomatal conductance decreased throughout the air influx rate sequence, but the rate of decrease was similar to the decrease in $CO_2$ assimilation rate observed under continuous air influx rate conditions. In starch granules during grain filling period under air influx rate(440 ml / min.) , compound starch granules were loosing and a number of hollows were observed in surface of single starch granules. Evidences from several approaches indicate that synchronization of stomatal conductance and$CO_2$ assimilation rate was closely inter-related tinder increase of air influx rate and increase of air influx rate influenced the$CO_2$ uptake in photosynthetic processes and compound starch granule, as 'end products' of photosynthesis.

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Effects of Design Parameters on the Thermal Performance of a Brushless DC Motor (BLDC 모터의 열적 성능에 대한 설계 인자의 영향)

  • Kim, Min-Soo;Lee, Kwan-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.2
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    • pp.141-148
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    • 2008
  • A numerical simulation of brushless DC motor is performed to elucidate thermo-flow characteristics in winding and bearing with heat generation. Rotation of rotor and blades drives influx of ambient air into the rotor inlet. Recirculation zone exists in the tiny interfaces between windings. The flow separation causes poor cooling performance in bearing part and therefore the redesign of the bearing groove is required. The design parameters such as the inlet location, geometry and bearing groove threshold angle have been selected in the present simulation. As the inlet location moves inward in the radial direction, total incoming flow rate and heat transfer rate are increased. Total incoming flow rate is increased with increasing the inlet inner length. The effect of the bearing groove threshold angle on the thermal performance is less than that of other design parameters.

Bed Combustion in a Furnace Enclosure - a Model for the MSW Incinerator

  • Ryu, Chang-Kook;Shin, Dong-Hoon;Choi, Sang-Min
    • Journal of the Korean Society of Combustion
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    • v.7 no.1
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    • pp.58-64
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    • 2002
  • The bed combustion in an incinerator interacts with the gas flow region through heat and mass transfer. Combined bed combustion and gas flow simulations are performed to investigate this coupled interaction for various operating conditions and furnace configurations. Radiation onto the bed from the furnace is interrelated with the combustion characteristics in the bed, and is also affected by the flow pattern in the gas flow region. Since the contribution of gaseous emission to the total radiation is significant, an adequate flow pattern in a well-designed furnace shape would lead to an increased heat influx on the bed, especially in the early stage of the waste combustion. Advancing the initiation point of the waste combustion can also reduce the size of the lower gas temperature region above the bed, which can be achieved by controlling operating conditions such as the waste feeding rate, the bed height and the primary air flow distribution.

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Effects of the Odor Abatement System in a Naturally Ventilated Growing Finishing Pig House (자연환기식 육성.비육돈사의 악취탈취장치 적용효과)

  • Lee, S.H.;Yun, N.K.;Kim, K.W.;Yum, S.H.;Cho, Y.H.
    • Journal of Animal Environmental Science
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    • v.14 no.1
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    • pp.31-38
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    • 2008
  • Ammonia gas is one of the malodorous gases from swine production facilities, such as manure storage tank, manure fermentation facilities, and livestock houses, etc. Ammonia gas from swine house is being emitted at relatively low concentrations throughout the year. Therefore, livestock facilities were continuously ventilated to supply fresh air for respiration of the animals internal the livestock facilities. The swine facilities need very high ventilation rate to control the inside environmental conditions. The deodorization system of the livestock facilities must be developed considering the ventilation rates. The odor abatement system was installed in order to improve the internal environment of the naturally ventilated growing-finishing pig house. The system which distributes the deodorized air into inner space of the swine house by using plastic duct was installed. Since the internal environment, effected by the operation of the odor abatement system, is monitored by closing the winch curtain installed on the side wall of the pig house, the experiment was practiced at the season when the internal environment becomes aggravated, winter. The effects on the improvement in the internal environment of swine house by operating the odor abatement system are as follows ; 1. By re-distributing the air which was deodorized by the odor abatement system installed in the pig house, the result showed that the concentration of ammonia gas is decreased approximately 33.3% compared with that before operating odor abatement system. 2. The effect on the pig house's ammonia gas reduction was found that the ventilation rate was less than $0.5m^3$/min head. The effect of the operation of the odor abatement system showed to be scarce when the ventilation rate increases because of the influx of external fresh air makes the quantity of diluted air more than those of the odor abatement system. 3. The perishment rate of the pigs which were brooded until slaughtering decreased about 3.8% by operating the odor abatement system in the growing-finishing pig house. Also, after operating the odor abatement system, the stinging of the eyes, suspension dust, etc were decreased when going into swine house for management.

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Design for a Fuse Element of Sub-miniature Fuse with High Breaking Capacity Characteristics (높은 차단용량 특성을 갖는 초소형 미니어처 퓨즈의 가용체 설계)

  • Ahn, Chang Hwan
    • Journal of the Institute of Electronics and Information Engineers
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    • v.54 no.3
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    • pp.131-137
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    • 2017
  • In order to safely protect high over current flowing into the main circuit at short-circuit without any explosion or fire, the enclosed cartridge fuse with a high interrupting capacity should be applied. But this fuse is impossible to be applied to an inner electronic circuit because of a limited space problem result from the miniaturization trend of products. Therefore, it is necessary to apply a sub-miniature fuse with a relatively small size. However the semi-enclosed fuse which is more free for an influx of air than the enclosed cartridge fuse and is possible to protect fuse elements with chemical and physical combination can be adoptable. But it has a limit of implementing the characteristic of a high breaking capacity. For these reasons, the Fe-42wt%Ni fuse elements alloy and fuse-link with less space were designed to increase a breaking capacity of sub-miniature fuse and its safety for fire and explosion was confirmed in this paper.