• Title/Summary/Keyword: Throw length

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Study on the Threshing and Separating Performanee of the Newly Developed Throw-in Type Thresher (투입식 탈곡기의 탈곡 및 선별 성능에 관한 연구)

  • 이승규;정창규김성래
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.17 no.3
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    • pp.3878-3884
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    • 1975
  • This study was carried out to develop the throw-in type thresher with its size as small as possible. Developing the smallest possible size of the throw-in type thresher has been very important to increase mobility and to reduce the machine price. The thresher that developed for this purpose was tested as to threshing and separation performance for the samples collected in eight catch boxes under the concave while threshing. The amount of grain collected in each compartments was measured and the threshing and separating pattern along the total span of the threshing drum was determined. The performance of separating and threshing units of the test thresher and threshing loss was evaluated by use of the developed grain separating apparatus and the method for measuring the grain separating performance of threshers. The results are summarized as follows; 1. The unthreshed grain (drum losses) and semi-threshed grain did not appeared at all throughout the treatments. 2. When threshed by making use of the developed throw-in type thresher, the threshing grain loss at about 25 per cent grain moisture was about one-half when threshed at about 18 per cent grain moisture. 3. And its grain separating loss in higher feed rate was decreased in comparison with that of lower feed rate. These results suggests that the throw-in type thresher may be suitable for wet threshing and for higher feed rate of threshing. 4. Above 60 per cent of total grain passing through concave fell through the screen within a scant 30 cm from the feeding inlet. This threshing pattern may suggest that major threshing action may be finished before about one third of cylinder length. The required separating load extended over the whole drum span is so defferent that separating elements should be redesigned so as to accomodate this variable pattern of separation load. 5. It was apparent from the experiment that the length of the threshing drum of the throw-in type thresher could be reduced from 1285mm to about 1050mm without increasing grain separation loss greatly.

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Design Optimization of Nozzle Shape for a Jet Fan (제트송풍기 노즐의 형상최적설계)

  • Seo Seoung-Jin;Kim Kwang-Yong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.8 s.251
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    • pp.715-721
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    • 2006
  • In the present work, nozzle shape of a jet fan is optimized numerically using three-dimensional Reynolds-averaged Navier-Stokes analysis. Standard $k-{\epsilon}$ model is used as a turbulence closure. Response surface method is employed as an optimization technique. The objective function is defined as maximum throw distance. Three geometric variables, i.e., length and angle of nozzle, and interval between two nozzles, are selected as design variables. As the main result of the optimization, the throw distance has been improved effectively.

Effect of Circumferential Velocity from Guide Vane on the Nozzle Flow of a Jet Fan (제트팬 노즐내부 유동에 대한 고정익 출구 원주속도의 영향)

  • 최충현;이재헌
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.3
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    • pp.209-216
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    • 2001
  • A numerical study is peformed to investigate the effect of circumferential velocity generated by the guide vane on the nozzle flow of a jet fan, s a way of increasing the penetration force of jet fan with nozzle of 175mm diameter. For the validation of numerical results. the velocity is measured by a 5-hole pitot tube and flow visualization is conducted by the tuft method. Under the inlet condition that the maximum circumferential velocity in the stator outlet of the present jet fan is 1.8m/s, the axial velocity in the nozzle outlet has the feature that the velocity at the axis is low and the velocity near the wall high. Therefore, to increase the throw length of the jet fan, the configuration of the fairing and nozzle needs to be developed and the precise revise of the stator angle is required, In addition, the bigger the circumferential velocity, the smaller the axial velocity at the axis and the bigger non-uniformity of the flow distribution.

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ADPI Characteristics of a Line-Diffuser (라인-디퓨저의 ADPI특성에 관한 연구)

  • Lee, Jae-Heon;Cho, Young-Jin;Kang, Seok-Youn;Oh, Myung-Do
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.958-964
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    • 2001
  • It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the ADPI(Air Diffusion Performance Index) vs. T/L(Throw/Length) curve listed in conventional guide does not consider the perimetric heating load. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and to propose a selection guide for proper diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI value are obtained numerically with various heat load ratios and air flow rates. The ADPI values by numerical result were compared with existing experimental data to verify the method for evaluation of ADPI proposed in present study. In case of a high side wall diffuser, the ADPI decreased with increases of the flow rate on every heat load ratio of present study except 0.75. Also, the ADPI vs. T/L curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee comport thermal environment when diffusers are installed in perimeter zone.

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ADPI Characteristics of Line Diffuser in a Room with Perimetric Heating Load (측벽 부하가 존재하는 공간에 설치된 라인 디퓨져의 ADPI 특성에 관한 연구)

  • Cho Young-Jin;Kang Seok-Youn;Moon Jong -Sun;Lee Jae-Heon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1204-1211
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    • 2004
  • It is difficult to apply a conventional selection guide for diffusers when the diffuser is installed in a perimeter zone, because the air diffusion performance index (ADPI) vs. throw/length (T/L) ratio curve listed in conventional guide does not consider the perimetric heating load through the walls. The objective of this study is to evaluate the effect of the perimetric heating load on the ADPI and propose a selection guide for a proper line diffuser when perimetric heating load exists. The velocity and temperature distributions and the ADPI values are obtained numerically with various heat load ratios and air flow rates. The velocity and temperature distributions and the ADPI values are analyzed by CFD in case of various heat load ratios and air flow rates. Also, ADPI was calculated by those results. The ADPI values by numerical results are compared with an existing experimental data to verify the method for the evaluation of ADPI proposed in a present study. In case of a line diffuser installed at the high side wall, the ADPI decreases according to the increases of the flow rate on every heat load ratio of the present study except 0.75. The ADPI vs. T/L ratio curves have been proposed for the heat load ratios of 0.25, 0.5, 0.75 to guarantee the comport thermal environment when diffusers are installed in perimeter zone.

Effect of CrossFit Power Training on TPI OnBaseU Power Test and Golf Performance (크로스핏 파워 트레이닝이 TPI OnBaseU Power Test와 골프 수행력에 미치는 영향)

  • Chang Wook Kim
    • Korean Journal of Applied Biomechanics
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    • v.33 no.4
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    • pp.185-195
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    • 2023
  • Objective: The purpose of this study is to improve TPI OnBaseU Power Test and golf performance by conducting CrossFit power training. Method: Three male golf players from University B participated in this study. They had 3 to 4 years of golf experience and participated in 8 weeks of CrossFit power training. Results: OnBaseU Power Test: There was a lot of improvement in Sit up throw (27.9%) and Chest pass (10.58%), but there was not much improvement in Baseline Toss (R5.9, L9.8%) and Vertical Jump (4.1%). Golf shot data: There was a very statistically significant difference in Club speed, Ball speed, and Total Length, which are related to speed, and there was no difference in Club path and Smash factor, which are related to accuracy and posture. Conclusion: CrossFit power training was effective in improving TPI OnBaseU Power Test and golf performance (Club speed, Ball speed, Total Length).

O(N log N) ALGORITHM FOR FINDING PRIMARY TANDEM REPEATS IN A DNA GENOMIC SEQUENCE

  • Ma, Sang-Back;Jun, Hyeong-Hwa
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.9 no.1
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    • pp.1-7
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    • 2005
  • The genomes of organism are being published in an enormous speed. The genomes has a lot of intronic regions, and repeats constitute a substantial part of that. Repeats playa crucial role in DNA finger-printing, and detecting certain genomic diseases, such as Huntington disease, which has a high number of CAG repeats. Also, they throw important clues about the evolutionary history. Repeats are in two types, Tandem Repeats and Interspersed Repeats. In this paper we address ourselves to the problem of detecting Primary Tandem Repeats, which are tandem repeats that are not contained in any tandem repeats. We show that our algorithm takes O(n log n) time, where n is the length of genome.

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A Study on the Flow Characteristics of a Quick Injection Agitator (급속 분사식 교반기의 유동 특성 연구)

  • Youn, K.J.;Ahn, B.J.;Kim, Youn-J.
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.508-513
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    • 2003
  • A quick injection agitator is used to mix working fluids. In this study, numerical analyses are carried out to investigate the performance of a quick injection agitator with different gaps between the impeller and vacuum enhancer. A commercial CFD code is used to compute the 3-D viscous flow field within the impeller of agitatior. Numerical results are graphically depicted with different gaps. Special attention is paid to the following topics: pressure distribution, velocity gradient, volume fraction.

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Characteristic Evaluation of Line Diffusers for Air Quality Improvement of Laboratory (실험실 공기질 개선을 위한 라인디퓨져의 특성 평가)

  • Cho, Su-Hyen;Lee, Chul-Ku
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.6
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    • pp.14-22
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    • 2008
  • This study is aimed at suggesting a linear-type diffuser which is excellent in terms of range and elegance like existing diffusers in which amount and direction of wind can be freely controled, out of linear-type diffusers with the highest possibility to be adopted for living space of apartments whose height between floors is not so high and utilizing the linear-type diffuser in design. For the purpose, I examined necessary flow and noise properties of linear-type diffusers. Besides, I evaluated its ventilation capacity for persons in there by applying this in the actual living space. I evaluated features and air blast and found that in time of horizontal and vertical effusion, its T/L ratio is 1-1.5, similar to existing cardioid-type linear diffusers, while in time of slope effusion, it is similar to horizontal effusion in terms of range and it has medium figure in terms of pressure drop and effusion speed, indicating it can provide safe and pleasant indoor environment for persons in there in terms of ventilation.