• Title/Summary/Keyword: Current flow

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A Review on Lateral Flow Test Strip for Food Safety

  • Kim, Giyoung;Lim, Jongguk;Mo, Changyeun
    • Journal of Biosystems Engineering
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    • 제40권3호
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    • pp.277-283
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    • 2015
  • Background: Foodborne disease outbreaks from various food sources are a major health concern worldwide. Current methods for detection of foodborne pathogens are both expensive and time-consuming. Purpose: This review aims to present the current information available on the use of lateral flow test strips to detect pathogens in food products to enhance food safety. Results: Frequent foodborne disease outbreaks from various food sources have increased the need for rapid and easy methods for routine analysis of foodborne pathogens. Present detection methods for foodborne pathogens require expensive instruments, experts, and long time for sample analysis. Lateral flow test strips have drawn attention in recent years because of their ability to detect analytes quickly and easily. This review focuses on the principle of the lateral flow test, the various formats of lateral flow test strips, recognition elements, labeling tags, and reading instruments. In addition, this review also discusses the future prospects for the lateral flow test strips.

남극 세종기지의 전산유동해석에 의한 풍력자원평가 (Wind Resource Assessment of the Antarctic King Sejong Station by Computational Flow Analysis)

  • 김석우;김현구
    • 한국태양에너지학회 논문집
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    • 제27권3호
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    • pp.29-35
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    • 2007
  • In accordance with Madrid and Kyoto Protocols, a 10kw wind turbine installed about 625m away from the King Sejong Station in the Antarctica has been in operation successfully. The current location of the wind turbine has different geographic surroundings from the previous candidate site considered in 2005 and that makes re-evaluation of wind resource at the current site including geographic effects necessary. Especially, strong wind flow derived by steep and complex terrain is dominant in the Antarctica so that computational flow analysis is required. The wind rose measured at the previous and current installation location are identical with strong meteorological correlation but prevailing directions of wind power density are different because of local wind acceleration due to complex terrain. Numerical analysis explains which effects brings this discordance between the two sites, and a design guideline required for additional wind turbine installation has been secured.

Evaluation of Mixing Performance in Several Designs for Microfluidic Channel Mixers

  • 왕양양;서용권;강상모
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2007년도 춘계학술대회B
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    • pp.2811-2816
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    • 2007
  • We conducted a numerical study of AC-electroosmotic (alternating current) effect on the fluid flow and mixing in a 3-D microchannel. The microchannel used as an efficient micro-mixer is composed of a channel and a series of pairs of electrodes attached in zigzag pattern on the bottom wall. The AC electric field is applied to the electrodes so that a steady flow current takes place around the electrodes. This current is flowing across the channel and thus contributing to the mixing of the fluid within the channel. We performed numerical simulations by using a commercial code to obtain a steady flow field. This steady flow is then used in evaluation of the mixing performance via the concept of mixing index. It was found that good combination of two kinds of electrode, which gave us a good mixing, is not simple harmonic. And when the length ratio of these two kinds of electrode is 2:1, we can get the best mixing effect.

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자유수평축 조류발전 시스템의 3차원 유동특성 (3D Flow Characteristics of a Free-Horizontal-Axis-Turbine Tidal Power Generation System)

  • 최진형;도덕희;조효제;이연원
    • 한국가시화정보학회지
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    • 제8권2호
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    • pp.51-55
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    • 2010
  • Flow characteristics of a free-horizontal-axis-turbine (FHAT) current power generation system have been investigated by the use of a volumetric PTV. Three types of FHAT system (S50, SE50, S65) have been tested under the current speed 1.35 knot, 1.5 knot and 2 knot. The width of the blade installed around the body is 50 mm. Based upon the power generation characteristics of the FHAT, the flow features of the blade have been investigated. Among the three models it has been verified that the S65 is the most appropriate for power generations.

남극 세종기지의 전산유동해석에 의한 풍력자원평가 (Wind Resource Assessment of the Antarctic King Sejong Station by Computational Flow Analysis)

  • 김석우;김현구
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.376-377
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    • 2007
  • In accordance with Madrid and Kyoto Protocols, a 10kW wind turbine installed about 625m away from the King Sejong Station in the Antarctica has been in operation successfully. The current location of the wind turbine has different geographic surroundings from the previous candidate site considered in 2005 and that makes re-evaluation of wind resource at the current site including geographic effects necessary. Especially, strong wind flow derived by steep and complex terrain is dominant in the Antarctica so that computational flow analysis is required. The wind rose measured at the previous and current installation location are identical with strong meteorological correlation but prevailing directions of wind power density are different because of local wind acceleration due to complex terrain. Numerical analysis explains which effects brings this discordance between the two sites, and a design guideline required for additional wind turbine installation has been secured.

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단일채널 고온초전도 자속흐름 트랜지스터의 I-V 특성 비교분석 (A Comparative Analysis of I-V Characteristics in a single Channel Superconducting Flux Flow Transistor)

  • 고석철;강형곤;임성훈;최명호;이종화;한병성
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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    • pp.107-110
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    • 2003
  • We have proposed a model to describe the current-voltage characteristics of fabricated devices using the Biot-Savart's law in order to develop superconducting flux flow transistors, The measured and calculated values, including induced voltage, transresistance and current gain were investigated in relation to the parallel flow of the vortices in a single microbridge. The predictions agreed very well with measured results.

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암모니아-물 흡수식 시스템에서 유하액막식 발생기의 해석 (Analysis of Falling-film Generator in Ammonia-water Absorption System)

  • 김병주;손병후;구기갑
    • 설비공학논문집
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    • 제13권5호
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    • pp.422-430
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    • 2001
  • In the present study, an evaporative generation process of ammonia-water solution film on the vertical plate was analysed. For the utilization of waste heat, hot water of low temperature was used as the heat source. The continuity, momentum, energy and diffusion equations for the solution film and vapor mixture were formulated in integral forms and solved numerically. Counter-current solution-vapor flow resulted in the refrigerant vapor of the higher ammonia concentration than that of co-current flow. Eve the rectification of refrigerant vapor was observed near the inlet of solution film in counter-current flow. For the optimum operation of generator using hot water, numerical experiments, based on the heat exchange and generation efficiencies. revealed the inter-relationships among the Reynolds number of the solution film and hot water, and the length of generator. Enhancement of heat and mass transport in the solution film was found to be very effective for the improvement of generation performance, especially at high solution flow rate.

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$SF_6$아크의 절연회복특성 해석 (Analysis Of Dielectric Recovery Characteristics for $SF_6$ Gas-Blast AFC)

  • 송기동;이병윤;박경엽;박정후
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제51권6호
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    • pp.273-284
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    • 2002
  • In this paper, computer simulations of the physical Phenomena occurring in the arc region before and after current zero were carried out to evaluate the dielectric recovery characteristics of two types of double-flow nozzles. A commercial CFD Program "PHOENICS" is used for the simulation and the user-coded subroutines to consider the arcing phenomena were added to this program by the authors. The computed results were verified by the comparison with the test results presented by the research group of BBC. In order to investigate the state of the arc region after current zero, the simulation was carried out with four steps. They are cold gas flow analysis, steady state arc simulation, transient arc simulation before current zero, transient hot gas flow simulation after current zero. The semi-experimental arc radiation model is adapted to consider the radiation energy transport and Prandtl′s mixing length model is employed as the turbulence model. The electric field and the magnetic field were calculated with the same grid structure used for the simulation of the flow field. The streamer criterion was introduced to evaluate the dielectric recovery characteristics after current zero. Compared with the results obtained by assuming the current zero state in the former studies, it has been found that the results obtained by considering the state before current zerowere more accurate.

전산유체역학(CFD)을 이용한 저수조 내부 유동장 해석 (Analysis of Water Storage Tank Flowfield using Computational Fluid Dynamics (CFD) Simulation)

  • 최연우;한민수;송준혁;왕창근
    • 한국물환경학회지
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    • 제34권2호
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    • pp.173-182
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    • 2018
  • Reservoirs, facilities to store water, are being used in several fields for their ability to hold back a large quantity of water for a long time before the water is actually used. However, at the same time, the reservoirs are considered to have a flaw: the longer they store water, the more the quality of water in these reservoirs deteriorates. Further, when the reservoirs are large, they are more likely to have dead-water regions in out-of-the way spots far from either an in-current or an ex-current canal. This study conducted a Computational Fluid Dynamic (CFD) simulation and tried to figure out the internal flow inside each of the reservoirs with different in-current canals built by the multiple hoe screw nozzle method and the drop in-current method. The drop in-current method is more frequently used. According to the analysis of the internal flow inside each reservoir with the different methods applied, we found that the reservoir with the drop in-current canal would have two rotary currents in the lower region of the reservoir and that the velocity of flow would decrease. For a reservoir with the screw nozzle method, a single rotary current occurred, and inside the reservoir, regardless of height, the current turned out to flow in a regular manner.

단위전류당 고유량 유기용매 이송을 위한 다공성 실리콘막 전기침투 펌프의 개발 (Development of Porous Silicon Electro-osmotic Pumps for High Flow Rate Per Current Flow Delivery of Organic Solvents)

  • 권길성;김대중
    • 대한기계학회논문집B
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    • 제34권2호
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    • pp.105-111
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    • 2010
  • 양극산화법과 DRIE 법으로 제작된 다공성 실리콘막을 이용하여 두 종류의 전기침투 펌프를 제작하였다. 펌프의 성능은 유기용매를 이용하여 유량과 단위전류당 유량으로 측정하였다. 두 종류 펌프 모두 기존의 다공성 유리막으로 제작된 전기침투 펌프보다 성능이 우월했다. 특히 DRIE 법으로 제작된 다공성 실리콘막은 유량과 단위전류당 유량이 모두 월등한 성능을 보였다. DRIE 법은 널리 알려진 방법이기에 이와 같이 제작된 펌프는 다양한 응용 분야에 비교적 쉽게 적용될 것으로 기대된다.