• Title/Summary/Keyword: pod characteristics

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Determination of Seeding and Harvesting Time in Snap Bean

  • Lee, Sang-Soon;Lee, Jeong-Dong;Hwang, Young-Hyun
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.46 no.1
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    • pp.64-67
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    • 2001
  • Snap bean is a new corp in Korea but believed to have a great deal of potentials for both domestic and overseas markets. The present study was performed to obtain the basic information about growth- and quality-related characteristics and to determinate the optimum seeding date and harvesting time for snap bean. Pod yield was significantly affected by seeding date. The highest pod yield was obtained from March 20 for determinate type and April 4 for indeterminate one, respectively, with the range of 13.0-23.7 t/ha. The pod length of indeterminate type was over 13cm, and the pod length was over 5 grams. The pod width for tested varieties was less than 1.0cm. Considering the pod growth characters such as pod length, pod width, and pod weight, the optimum harvesting time for immature pods of snap bean was supposed to be from 15 to 20 days after flowering. The daily yield of snap bean was begun to sharply increase from 15 days after the first flowering and the maximum yield was recorded at 30 days after flowering. For the accumulated yield, nearly 90% of total yield was obtained in 42 days after flowering.

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A Study on the Pressure and Velocity Distributions by POD Shape of Hydrofoil Vessel (쾌속여객선의 POD 형상에 따른 압력과 속도 분포에 관한 연구)

  • Lee, Chun-Ki;Lim, Tae-Woo;Moon, Seong-Bae
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.4
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    • pp.831-837
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    • 2014
  • This paper focuses on the effects of the changes in the resistance characteristics caused by the changes of the POD shape installed in the Hydrofoil vessel, using the CFD(Computational Fluid Dynamics). We input the POD sections' basic shape as the origin of the x and y axis. Then as we cut the x-axis 0 to 2 cm, and the more we cut it, the total resistance value had increased. However, we have recognized the fact that as we cut the POD section, 3 to 5 cm, the resistance value had rather decreased. Furthermore we found out the result that as the cut partition was larger; the POD cross-section would decrease, resulting in the linear decrease of the viscous force.

Proper Orthogonal Decomposition Analysis of Dynamic Wind Pressures Acting on a Tall Tower Model (고층 타워에 작용하는 동적 풍압력의 POD 방법을 이용한 시공간적 특성 해석)

  • Yi, Mee-Hwa;Ham, Hee-Jung
    • Journal of Industrial Technology
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    • v.24 no.B
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    • pp.29-36
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    • 2004
  • The wind and wind-induced dynamic wind pressures fluctuate irregularly according to time and space. In this study, the proper orthogonal decomposition(POD) technique is applied to wind pressures acting on a tall tower model, and the following results are found: the along-wind and across-wind forces can be reconstructed by only four dominant POD modes, and the reconstructed errors are 4.71% and 22%, respectively for across-wind and along-wind directions. The physical meanings for dominant modes are also presented in the paper. The POD analysis can compress complex wind pressure data only by a few dominant modes and interpret spatio-temporal characteristics of wind pressure by novel way while existing statistical methods do not have such benefits.

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On the Model Tests for POD Propulsion Ships

  • Go Seokcheon;Seo Heungwon;Chang Bong Jun
    • Journal of Ship and Ocean Technology
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    • v.9 no.1
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    • pp.1-10
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    • 2005
  • The procedures of model test and performance prediction for the CRP-POD propulsion ships, are studied. At the CRP-POD system, which are highly applicable to ultra large container carriers, RPM ratio of two propellers is not fixed, unlike conventional CRP system, and hence the power of each propeller must be predicted respectively. In this paper, a CRP-POD system is designed for 10,000 TEU class ultra large container carriers, and the characteristics of the CRP-POD system are experimentally studied. Finally, based on this study, the procedure of powering performance evaluation for CRP-POD propulsion ships is suggested. However, further studies on quantitative correction of the present procedure are required.

Stability Analysis of an Mounting Equipment for External Pod on Aircraft by Road Test (항공기 외장형 포드 장착장비의 주행 안정성 분석)

  • Lee, Jong-Hak;Jang, Jong-Youn;Kang, Young-Sik;Choi, Ji-Ho;Kang, Dong-Seok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2013.10a
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    • pp.424-429
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    • 2013
  • The trolley carrying the pod moves along by the airfield runway. The pod through the trolley are subjected to vibration arising from the ground state, the precision optical components in the pod can have a significant impact. The road tests were conducted by using the measurement pod to remove the risk for the project. The measurement pod was composed with the ACRA, sensors, battery. The accelerometers were attached to get the acceleration through the road condition. The PSD envelop was calculated by FFT from the acceleration. The driving safety was proven through comparing the measurement data and MIL-STD-810G specification.

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Finite Element Model Building Procedure of an External Mounting Pod for Structural Dynamic Characteristics Analysis of an Aircraft (항공기 구조 동특성 해석을 위한 외부 장착 포드의 유한요소모델 구축 절차)

  • Lee, Jong-Hak;Ryu, Gu-Hyun;Yang, Sung-Chul;Jung, Dae-Yoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.72-77
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    • 2011
  • In this study, the natural frequencies and mode shape of an external mounting pod were verified using the modal analysis and modal testing technique for a pod mounted on an aircraft. The procedure associated with the FEM building of an external mounted pod to predict the dynamic behavior of aircraft structures is described. The simplified FEM reflecting the results of the modal testing of a pod is built through the optimization, applied to the structural dynamic model of an Aircraft, used to verified the stability of vibration and flutter of an aircraft.

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Proper Orthogonal Decomposition Analysis of Flow Characteristics in Hybrid Rocket Engine (POD에 의한 하이브리드 로켓 연소실의 유동특성 해석)

  • Park, Charyeom;Lee, Changjin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.42 no.5
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    • pp.383-389
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    • 2014
  • POD analysis has been done to investigate the internal flow characteristics using LES calculation results of hybrid rocket combustion chamber. The special emphasis was put on the change in the mode energy distribution caused by the installation of diaphragm compared to the baseline case. Also the comparison was made to investigate the effect of wall blowing on the changes in the mode energy between the regions near and far from the diaphragm. For baseline case, POD results clearly distinguish the primary mode containing most of flow energy from the rest of flow modes (2-9 mode) depicting small scale modes. Also, the increase in the energy of flow modes 2-5 is responsible for the formation of relatively large scale structures due to diaphragm. In addition, the comparison of mode energy distributions of flow fields with diaphragm shows similar patterns in both wall blowing and no blowing case. This implies that the local increase in regression rate just after the diaphragm is directly associated with the increase in energy distributions of 2-5 modes.

Growth and Optimum Harvesting Time of Pod-edible Peas (Pisum sativum L.)

  • Moon, Hyun-Sook;Hwang, Young-Hyun
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.45 no.2
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    • pp.93-96
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    • 2000
  • The present study was performed to obtain the basic information about growth and quality related characteristics and optimum harvesting time for podedible pea which is a new crop in Korea but believed to have a great deal of potentials for both domestic and overseas markets. They can be consumed either as a fresh succulent vegetable or as tender green pods. The daily green pod yield of pod-edible peas started to increase from ten days after flowering and the maximum yield was recorded on 26 days after flowering. Ninety percent of pod yields could be harvested from 16 to 36 days after flowering. Mean green pod yield for the tested varieties was approximately 8.0 t/ha. Total vitamin C content of pod-edible peas showed continuously decreasing trends from five days after flowering. The highest sucrose content was obtained at ten days after flowering. The highest panel score based on sweetness, chewiness, and hardness for the processed green pods was shown at 10-15 days after flowering in all varieties tested, indicating that the optimum harvesting time for pod-edible peas was considered to be 10-15 days after flowering.

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Pressure distribution near truncated POD attached on hydrofoil vessel (Hydrofoil 선박용 POD 변형에 따른 압력분포 특성)

  • Lee, Chun-Ki;Kim, Hee-Sung;Moon, Serng-Bae
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.9
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    • pp.1106-1111
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    • 2014
  • This paper has a purpose to find out the characteristics of pressure distribution according to the POD shape installed in the Hydrofoil vessel, using the CFD. The results showed that as we cut the POD cross-section's basic shape along the x-axis from 0 to 8cm, the viscous resistance had decreased, but then the pressure resistance had increased modestly. However, the cutoff length of POD cross-section shape has close to 9cm, the viscous drag had increased and the pressure drag had decreased. As a result, we found out that the pressure resistance made more effects in POD shape than the viscous resistance, and the total resistance decreased near the 9cm of cutoff length.

Study of a Characteristics of Maneuvering Mathematical Model of Twin POD Cruise Ship (2축 POD 여객선의 조종운동 수학모형 특성 연구)

  • Kim, Yeon-Gyu;Yun, Kun-Hang;Kim, Sun-Young;Son, Nam-Sun
    • Journal of the Society of Naval Architects of Korea
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    • v.50 no.6
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    • pp.429-435
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    • 2013
  • Recently, to improve the safety and maneuverability at fairway around harbor the POD system has been equipped on a ship. And the interest about maneuvering characteristics of a cruise ship has been increasing. In this paper the mathematical model of maneuvering motion of a cruise ship with twin POD system in general speed and slow speed are presented. And the maneuvering coefficients of mathematical model are obtained from the captive model tests using CPMC(Computerized Planar Motion Carriage). Computer simulation using mathematical model in general speed and slow speed are carried out and compared with the results of free running model test with the same model ship. The differences between the mathematical models are compared and discussed. In this paper the mathematical models, the results of captive model test and simulation results are presented.