• 제목/요약/키워드: Flow characteristic analysis

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A Study on the Development Model of Life-Type Tourism Destination - Focusing on the Japanese Practical Case - (농촌지역 생활형 (휴양)관광지 발전모델 연구 - 일본의 사례를 중심으로 -)

  • Park, Gu-Won
    • Journal of Korean Society of Rural Planning
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    • v.21 no.4
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    • pp.139-155
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    • 2015
  • This study was conducted to effectively develop rural tourism in Korea. For the purpose, tourism that can develop with local industries and cultures together was designated as life-type tourism and development models of such tourism were reviewed based on an understanding that province-oriented tourism is necessary. An analysis of three actual cases of Japan led to following results. First, life-type tourist destinations can be developed in connection with making local areas based on their special themes, can be developed in relation to their life cultures based on their peculiar life cultures and can be developed in creative forms using characteristic environment and organizational culture of those areas. In pursuing life-type tourist attractions, it will be possible to make practical development using it with those three basic models. Second, it is important to form a flow covering the entire regions based on their own special themes, to build cyclical structure of regions and tourism and tourism and industries and to create overall conditions that can help local residents get benefits and join together, in order to develop such life-type tourist destinations. Development of life-type resort tourist destinations needs roles of practical organizations that can effectively manage them, but such organizations should be dynamic and should be distant from management of money as much as possible.

Analysis of Breakthrough Curves and Mass Transfer Resistance for Phenol Adsorption in a Fixed-bed Process Packed with Activated Carbon (활성탄을 충전한 고정층에서 페놀 흡착에 따른 파과곡선과 물질전달저항 해석)

  • You, Hae-Na;Kam, Sang-Kyu;Lee, Min-Gyu
    • Journal of Environmental Science International
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    • v.23 no.1
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    • pp.53-60
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    • 2014
  • Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time ($t_{0.05}$), saturation time ($t_{0.95}$), length of mass transfer zone ($L_{MTZ}$), adsorptive capacity (W), and adsorption rate constant ($K_a$) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer $L_{MTZ}$ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.

Development of Evaluation Technology of Mechanical Properties Using Continuous Indentation Method (연속압입시험법을 이용한 소재의 기계적 물성 평가기술 연구)

  • Lee, Jeong-Hwan;Ok, Myoung-Ryul;Lee, Yun-Hee;Ahn, Jeong-Hoon;Kwon, Dong-Il
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.703-708
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    • 1997
  • Continuous indentation test is a very powerful method to monitor the materials reliability since it is very simple, easy and almost non-destructive. It can provide material properties such as elastic modulus, yield strength, work-hardening exponent, etc., than the conventional hardness test. In our study, the true stress-strain curve is derived from the indentation load-depth curve. For this, average indentation strain is defined and the flow stress is obtained from the analysis of the indentation stress field. The residual stress is analyzed from the variation of the indentation behavior with the applied residual stress. And the estimation of fracture characteristic is tried by considering the conventional fracture toughness modeling and the stress/strain state under the spherical indenter.

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A Study on the Spacer Installation Method for 2-Conductor Bundle Transmission Lines (2도체 송전선로의 스페이서 취부방식 연구)

  • Min, Byeong-Wook;Kim, Woo-Kyum;Choi, Han-Yeol;Park, Kee-Yong;Kim, Won-Jin;Park, Jae-Ung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.333-334
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    • 2008
  • Overhead transmission lines are classified by the number of sub conductors per phase. Korean transmission lines use two, four, or six-conductor bundle. Bundle of conductors must have spacers or spacer dampers which keep the proper distance between sub conductors. They can prevent conductors from being vibrated or twisted due to the wind. As for the two-conductor bundle, alternating current flow generates absorption force between sub conductors which may cause a collision of sub conductors. To prevent sub conductors from being vibrated, twisted, and collided, spacer or spacer damper installation method is designed considering vibration characteristics of sub conductors. We have spacer installation method for four or six-conductor bundle lines. However, we don't have it for two-conductor bundle ones. So we have installed spacers at regular intervals in two-conductor bundle lines, and it caused rigid body oscillation of conductors due to the wind which made a flashover between conductors. This paper introduces a vibration characteristic analysis of two-conductor bundle and proposes a spacer installation method for two-conductor bundle lines.

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Induction of Intrinsic and Extrinsic Apoptosis Pathways in the Human Leukemic MOLT-4 Cell Line by Terpinen-4-ol

  • Khaw-On, Patompong;Banjerdpongchai, Ratana
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.7
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    • pp.3073-3076
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    • 2012
  • Terpinen-4-ol is a terpene found in the rhizome of Plai (Zingiber montanum (Koenig) Link ex Dietr.). In this study apoptogenic activity and mechanisms of cell death induced by terpinen-4-ol were investigated in the human leukemic MOLT-4 cell line. Terpinen-4-ol exhibited cytotoxicity in MOLT-4 cells, with characteristic morphological features of apoptosis by Wright's staining. The mode of cell death was confirmed to be apoptosis by flow cytometric analysis after staining with annexin V-FITC and propidium iodide. A sub-G1 peak in DNA histograms of cell cycle assays was observed. Terpinen-4-ol induced-MOLT-4 cell apoptosis mediated through an intrinsic pathway involving the loss of mitochondrial transmembrane potential (MTP) and release of cytochrome c into the cytosol. In addition, terpinen-4-ol also induced apoptosis via an extrinsic pathway by caspase-8 activation resulting in the cleavage of cytosolic Bid. Truncated-Bid (tBid) translocated to mitochondria and activated the mitochondrial pathway in conjunction with down-regulation of Bcl-2 protein expression. Caspase-3 activity also increased. In conclusion, terpinen-4-ol can induce human leukemic MOLT-4 cell apoptosis via both intrinsic and extrinsic pathways.

A Study on the Reaction Force Characteristics of the Gas Spring for the Automotive (자동차용 가스 스프링의 반력 특성에 관한 연구)

  • Lee, Choon Tae
    • Journal of Drive and Control
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    • v.12 no.4
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    • pp.35-40
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    • 2015
  • A gas spring provides support force for lifting, positioning, lowering, and counterbalancing weights. It offers a wide range of reaction force with a flat force characteristic, simple mounting, compact size, speed controlled damping, and cushioned end motion. The most common usage is as a support on a horizontally hinged automotive tail gate. However, its versatility and ease of use has been applied in many other industrial applications ranging from office equipment to off-road vehicles. The cylinder of a gas spring is filled with compressed nitrogen gas, which is applied with equal pressure on both sides of the piston. The surface area of the rod side of the piston is smaller than the opposite side, producing a pushing force. The magnitude of the reaction force is determined by the cross-sectional area of the piston rod and the internal pressure inside the cylinder. The reaction force is influenced by many design parameters such as initial chamber volume, diameter ratio, etc. In this paper, we investigated the reaction force characteristics and carried out parameter sensitivity analysis for the design parameters of a gas spring.

An Evaluation for Predicting the Far Wake of Tidal Turbines

  • Yang, C.J.;Hoang, A.D.
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2012.06a
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    • pp.155-156
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    • 2012
  • In the modern age, as man's demand of energy is continuously grew, tidal becomes one of the sustainable energy sources that have been investigating thoroughly recently. Tidal turbine has proved high potential as a future power-generating device. To effectively capture tidal energy on site, a group of tidal turbines should be used and positioned in some formation with proper size and space so that energy can be absorbed from multiple point. Thus, the turbines together with the flow filed becomes a huge domain, a tidal farm. So, it becomes more convenient if a whole turbine farm is simulated by means of actuator discs since the time and cost for analysis can be reduced. This paper aims to evaluate the operating performance (power efficiency and energy restoration rate), mutual influence (for different longitudinal and lateral spaces), the influence of velocity profiles, turbulence intensity and the far wake characteristic of tidal turbines operating in farm formation. The results of this study help contributing to the present development of tidal turbine as the future potential energy conversion machinery.

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Development of Multi-dimensional Limiting Process for Multi-dimensional Compressible Flow (다차원 압축성 유동 해석을 위한 MLP 기법의 개발)

  • 윤성환;김종암;김규홍
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.7
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    • pp.1-11
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    • 2006
  • Through the analysis of conventional TVD limiters, a new multi-dimensional limiting function is derived for an oscillation control in multi-dimensional flows. Then, Multi-dimensional Limiting Process (MLP) is developed with the multi-dimensional limiting function. The major advantage of MLP is to prevent oscillations across a multi-dimensional discontinuity, and it is readily compatible with more than 3rd order spatial interpolation. Moreover, MLP shows a good convergence characteristic in a steady problem and it is very simple to be implemented. Through numerical test cases, it is verified that MLP substantially improves accuracy, efficiency and robustness both in continuous and discontinuous flows.

Development of porthole Die on Aluminum Extrusion for the Automobile Control Arm (자동차용 컨트롤 암 알루미늄 열간 압출을 위한 포트홀 금형개발)

  • Joe, Young-June;Lee, Sang-Kon;Oh, Kae-Hee;Park, Sang-Woo;Lee, Woo-Sik;Jang, Gae-Won;Kim, Byung-Min
    • Journal of the Korean Society for Precision Engineering
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    • v.24 no.4 s.193
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    • pp.102-108
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    • 2007
  • The characteristic properties of aluminum, high strength stiffness to weight ratio, good formability, good corrosion resistence, and recycling potential make it the ideal candidate to replace heavier materials in the car to respond to the weight reduction demand within the automotive industry. In this paper, FE simulation was carried out to design an appropriate extrusion die for the automobile control arm. Based on the FE simulation result, a new die design has been proposed for uniform material flow in the cross section of extruded product. And then the welding pressure, extrusion load, and the tendency of mandrel deflection were estimated to verify high quality. In the extrusion experiment, it was possible to produce sound product without defects.

Analysis on Design Parameters of Small Hydropower Sites with Rainfall Conditions (강우상태에 따른 소수력발전입지의 설계변수 특성 분석)

  • Lee, Chul-Hyung;Park, Wan-Soon
    • Journal of the Korean Solar Energy Society
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    • v.32 no.4
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    • pp.59-64
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    • 2012
  • The correlation between hydrologic performance design parameters of small hydro power(SHP) sites and rainfall condition have been analyzed for major river systems. The model, which can predict flow duration characteristic of stream, was developed to estimate the inflow caused from rainfall. And another model to predict hydrologic performance for SHP plants is established. Based on the models developed in this study, the hydrologic performance characteristics for SHP sites have been analyzed. The results show that the hydrologic performance characteristics of SHP sites have some difference between the river systems. Especially, the specific design flowrate and specific output of SHP sites located on North Han river and Nakdong river systems have large difference compared with other river systems. It was found that the hydrologic performance design parameters such as specific design flowrate and specific output were affected by rainfall condition in basin area of SHP sites.