• 제목/요약/키워드: HELIOS

검색결과 37건 처리시간 0.025초

MULTISAMS-HELIOS-SQUID 코드 체계를 이용한 AMBIDEXTER 노심의 물리적 모델링 (Physics Modeling of the AMBIDEXTER Core Using MULTISAMS-HELIOS-SQUID Code System)

  • 유영진;이영준;김태규;오세기
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 2000년도 추계 학술발표회 논문집
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    • pp.155-161
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    • 2000
  • 과거 몇몇 중대 원자력 발전사고와 핵무기의 사용은 원자력 산업에서 안전성과 핵확산의 문제를 부각시키는 계기가 되었다. 또한, 제 2세대 원자로로 대표되는 HWR, LWR 등의 상용 원자로가 가지는 안전성과 핵확산 방지에 대한 고유문제점은 원자력 산업이 해결해야할 대표적인 과제로 인식되고 있다.(중략)

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CFD ANALYSIS OF HEAVY LIQUID METAL FLOW IN THE CORE OF THE HELIOS LOOP

  • Batta, A.;Cho, Jae-Hyun;Class, A.G.;Hwang, Il-Soon
    • Nuclear Engineering and Technology
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    • 제42권6호
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    • pp.656-661
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    • 2010
  • Lead-alloys are very attractive nuclear coolants due to their thermo-hydraulic, chemical, and neutronic properties. By utilizing the HELIOS (Heavy Eutectic liquid metal Loop for Integral test of Operability and Safety of PEACER$^2$) facility, a thermal hydraulic benchmarking study has been conducted for the prediction of pressure loss in lead-alloy cooled advanced nuclear energy systems (LACANES). The loop has several complex components that cannot be readily characterized with available pressure loss correlations. Among these components is the core, composed of a vessel, a barrel, heaters separated by complex spacers, and the plenum. Due to the complex shape of the core, its pressure loss is comparable to that of the rest of the loop. Detailed CFD simulations employing different CFD codes are used to determine the pressure loss, and it is found that the spacers contribute to nearly 90 percent of the total pressure loss. In the system codes, spacers are usually accounted for; however, due to the lack of correlations for the exact spacer geometry, the accuracy of models relies strongly on assumptions used for modeling spacers. CFD can be used to determine an appropriate correlation. However, application of CFD also requires careful choice of turbulence models and numerical meshes, which are selected based on extensive experience with liquid metal flow simulations for the KALLA lab. In this paper consistent results of CFX and Star-CD are obtained and compared to measured data. Measured data of the pressure loss of the core are obtained with a differential pressure transducer located between the core inlet and outlet at a flow rate of 13.57kg/s.

The Great Saphenous Vein-An Underrated Recipient Vein in Free Flap Plasty for Lower Extremity Reconstruction: A Retrospective Monocenter Study

  • Meiwandi, Abdulwares;Kamper, Lars;Kuenzlen, Lara;Rieger, Ulrich M.;Bozkurt, Ahmet
    • Archives of Plastic Surgery
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    • 제49권5호
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    • pp.683-688
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    • 2022
  • Background Reconstruction of large soft tissue defects of the lower extremity often requires the use of free flaps. The main limiting factor and potential for complications lie in the selection of proper donor and recipient vessels for microvascular anastomosis. While the superficial veins of the lower leg are easier to dissect, they are thought to be more vulnerable to trauma and lead to a higher complication rate when using them instead of the deep accompanying veins as recipient vessels. No clear evidence exists that proves this concept. Methods We retrospectively studied the outcomes of 97 patients who underwent free flap plasty to reconstruct predominantly traumatic defects of the lower extremity at our institute. The most used flap was the gracilis muscle flap. We divided the population into three groups based on the recipient veins that were used for microvascular anastomosis and compared their outcomes. The primary outcome was the major complication rate. Results Overall flap survivability was 93.81%. The complication rates were not higher when using the great saphenous vein as a recipient vessel when comparing to utilizing the deep concomitant veins alone or the great saphenous vein in combination to the concomitant veins. Conclusions In free flap surgery of the lower extremity, the selection of the recipient veins should not be restricted to the deep accompanying veins of the main vessels. The superficial veins, especially the great saphenous vein, offer an underrated option when performing free flap reconstruction.

염생식물 갯질경 추출물의 미백 활성 (Whitening Activities of the Halophyte L. tetragonum (Thunberg) A. A. Bullock Extract in B16F10 Melanoma Cells)

  • 김민진;현광희;김지혜;한동환;김승영;이남호;현창구
    • KSBB Journal
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    • 제32권3호
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    • pp.218-233
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    • 2017
  • To identify the natural and novel cosmeceutical ingredients which have whitening function, we examined the effects of tyrosinase activity and melanin production on halophyte Limonium tetragonum (Thunb.) A. A. Bullock extracts. As a result, the extracts showed whitening effect with no cytotoxicity. Melanin contents of B16F10 melanoma cells were decreased in a dose-dependent manner at 50, 100, $200{\mu}g/mL$ treatment of the extracts. In tyrosinase activity inhibition test, L. tetragonum (Thunb.) A. A. Bullock extracts showed decreased tyrosinase activity as the concentration of ${\alpha}-MSH$ was increased. Furthermore, it was observed that the tyrosinase and MITF expression was significantly downregulated by adding L. tetragonum (Thunb.) A. A. Bullock extracts in ${\alpha}-MSH$, a melanogenesis inducing material, treated B16F10 melanoma cells. These results indicate that L. tetragonum (Thunb.) A. A. Bullock extract might be an effective whitening agent by inhibit melanin formation.

CRX-Hex: A Transport Theory Assembly Code Based on Characteristic Method for Hexagonal Geometry

  • Cho, Nam-Zin;Hong, Ser-Gi
    • 한국원자력학회:학술대회논문집
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    • 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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    • pp.28-33
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    • 1996
  • A transport theory code CRX-Hex based on characteristic methods with a general geometric tracking routine is developed for the heterogeneous hexagonal geometry. With the general geometric tracking routine, the formulation of the characteristic method is not changed. To test the code, it was applied to two benchmark problems which consist of complex meshes and compared with other codes (HELIOS, TWOHEX).

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