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VALIDATION OF NUMERICAL METHODS TO CALCULATE BYPASS FLOW IN A PRISMATIC GAS-COOLED REACTOR CORE

  • Tak, Nam-Il;Kim, Min-Hwan;Lim, Hong-Sik;Noh, Jae Man;Drzewiecki, Timothy J.;Seker, Volkan;Downar, Thomas J.;Kelly, Joseph
    • Nuclear Engineering and Technology
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    • v.45 no.6
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    • pp.745-752
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    • 2013
  • For thermo-fluid and safety analyses of a High Temperature Gas-cooled Reactor (HTGR), intensive efforts are in progress in the developments of the GAMMA+ code of Korea Atomic Energy Research Institute (KAERI) and the AGREE code of the University of Michigan (U of M). One of the important requirements for GAMMA+ and AGREE is an accurate modeling capability of a bypass flow in a prismatic core. Recently, a series of air experiments were performed at Seoul National University (SNU) in order to understand bypass flow behavior and generate an experimental database for the validation of computer codes. The main objective of the present work is to validate the GAMMA+ and AGREE codes using the experimental data published by SNU. The numerical results of the two codes were compared with the measured data. A good agreement was found between the calculations and the measurement. It was concluded that GAMMA+ and AGREE can reliably simulate the bypass flow behavior in a prismatic core.

Effect of Dietary vitamin E and Protein on Cadmium toxicity in Rats (카드뮴 투여 흰주의 혈청 및 간장성분에 미치는 식이성 비타민 E와 단백질의 영향)

  • 김혜진;조수열;박종민
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.19 no.1
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    • pp.27-34
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    • 1990
  • This study was undertatken to investigate the effects of dietary vitamin E on the toxicity of cadmium(Cd) in rats. The two variables were the supplmentary vitamin E(400lU/kg) and the protein amount(10.5% in the low protein diet and 18.0% in the normal protein diet) In cadmium treated rats net weight gain and food intake were decreased but improved by supplementation with vitamin E in the normal protein, hematocrit values reduced by Cd were significantly increased by the addition of vitamin E to normal protein diet in Cd intoxicated rats, The supplementation with vitamin E diminished the effect of Cd on aspartate aminotransf-rase and alanine aminotransferase activities in serum In Cd treated rats fed normal protein diet with vitamin E the contents of triglyceride were decreased and total-cholesterol contents were significantly reduced in serum and both of them in liver were markedly decreased. The activity of alcohol dehydrogenase in liver was decreased by Cd however supplementation with vitamin E reduced the effects of Cd on hepatic alcohol dehydrogenase. the results of this experiment indicated that there was some interaction between vitamin E and protein levels and supplementation with vitamin E had an effect more than protein levels oncd toxicity.

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Keypoints-Based 2D Virtual Try-on Network System

  • Pham, Duy Lai;Ngyuen, Nhat Tan;Chung, Sun-Tae
    • Journal of Korea Multimedia Society
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    • v.23 no.2
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    • pp.186-203
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    • 2020
  • Image-based Virtual Try-On Systems are among the most potential solution for virtual fitting which tries on a target clothes into a model person image and thus have attracted considerable research efforts. In many cases, current solutions for those fails in achieving naturally looking virtual fitted image where a target clothes is transferred into the body area of a model person of any shape and pose while keeping clothes context like texture, text, logo without distortion and artifacts. In this paper, we propose a new improved image-based virtual try-on network system based on keypoints, which we name as KP-VTON. The proposed KP-VTON first detects keypoints in the target clothes and reliably predicts keypoints in the clothes of a model person image by utilizing a dense human pose estimation. Then, through TPS transformation calculated by utilizing the keypoints as control points, the warped target clothes image, which is matched into the body area for wearing the target clothes, is obtained. Finally, a new try-on module adopting Attention U-Net is applied to handle more detailed synthesis of virtual fitted image. Extensive experiments on a well-known dataset show that the proposed KP-VTON performs better the state-of-the-art virtual try-on systems.

The Evaluation of Burst Pressure for Corroded Pipeline by Full Scale Burst Test (실배관 파열시험을 통한 부식배관의 파열압력 평가)

  • Kim, Yeong-Pyo;Baek, Jong-Hyeon;Kim, U-Sik;Go, Yeong-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.1
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    • pp.203-210
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    • 2002
  • The transmission pipeline industry spends many millions of dollars annually performing inline inspections, excavating sites of possible corrosion, and repairing or replacing damaged sections of pipe. New criteria fur evaluation of the integrity of corroded pipe have been developed in recent years to help in controlling these costs. These new criteria vary widely in their estimates of integrity and the most appropriate criterion fur a given pipeline is net always clear. This paper presents an overview, comparison and evaluation of acceptability criteria for corrosion deflects in pipelines. By full scale burst tests, this paper has assessed the relative accuracy of each of theses criteria in predicting burst pressure. Many of the criteria appear to be excessively conservative and indicate that deflects must be repaired when none is needed, based upon burst test data.

Fabrication of Thin Plate of Semisolid Material using Slope Plate Process and Development of Fabrication Apparatus (Slope plate 공법을 이용한 반응고 박판 및 제조 장치 개발)

  • Koo, Ja-Yoon;Bae, Jung-Woon;Jin, Chul-Kyu;Kang, Chung-Gil
    • Journal of Korea Foundry Society
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    • v.32 no.1
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    • pp.24-31
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    • 2012
  • In this study, semi-solid thin plate of A 356 aluminum alloy was fabricated by using slope plate apparatus and vacuum pressurization. Slope plate was used to produce semi-solid material with spheroidal microstructures. After molten metal was poured into the slope plate connected to the pouring hole of die, semi-solid material flowed into the die cavity by vacuum degree. The primary crystals of the cast metal became spheroidal. In order to increase the working pressure, gas pressurization of U shape was designed for fabrication of thin plate. For 3 bar of gas pressure and 60 mmHg of vacuum degree, thin plate was fabricated without defects on surface.

Contribution of Rice Mill Ash and Press Mud with Inorganic Fertilizers to Sugarcane Production in Old Himalayan Piedmont Plain Soils of Bangladesh

  • Paul G. C.;Rahman M.;Khan N. U.;Rahman A. B. M. M.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.50 no.2
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    • pp.108-111
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    • 2005
  • A field study was conducted to develop an economically suitable combination of organic and inorganic fertilizers for sugarcane cultivation in sandy acidic soil of a commercial sugarcane farm under Old Himalayan Piedmont Plain of Bangladesh. Results revealed that the treatment $T_4$ which received $75\%$ of Recommended fertilizers (N 120, P 35, K 100, S 25, Zn 2 kg $ha^{-1}$) + 10 Mg $ha^{-1}$ Rice mill ash + Mg $ha^{-1}$ press mud significantly produced higher sugarcane yield (72.34 Mg $ha^{-1}$) among all the treatments except $T_5$ having $100\%$ of Recommended fertilizers + 10 Mg $ha^{-1}$ Rice mill ash + 10 Mg $ha^{-1}$ press mud, which was identical. $T_4$ also gave the highest net economic benefit at Bangladesh Taka 15,920.47 per hectare from the added nutrient management. Thus, the integrated use with organic and inorganic fertilizer is highly essential for sustainable production of sugarcane in commercial farm of the region in Bangladesh, where it has been grown year after year.

A Comparative Study of Solvency Margin Regulation System : Focusing on Non-Life Insurance (지급여력제도의 국제적 정합성 연구 - 손해보험을 중심으로 -)

  • Jung, Hong-Joo;Nam, Sang-Wook;Park, Heung-Chan;Lee, Jae-Seok
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.17
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    • pp.93-125
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    • 2002
  • This paper aims to find a reasonable solvency margin system in non-life insurance industry and also to evaluate the appropriateness of the current solvency margin regulation system in Korea. The current solvency margin system in Korea, based on EU's solvency margin model, was introduced during the 1997 financial crisis. The solvency requirement is not based on non-life insurer's risk, but simply on written premiums. The current solvency margin for general insurance, such as fire, marine, and automobile insurance, is determined by the greater between a premium-based amount and a claim-based amount, where the premium-based solvency margin is calculated by multiplying the net written premium for the preceding year by the premium based solvency margin ratio. Also, the amount of solvency margin for long term insurance is set at 4% of the policy reserve of the long term insurance. Still, there exist many differences between the current solvency margin regulation system in Korea and EU's model. This paper focuses on the rationality of the solvency margin regulation system, and compares the current system in Korea with EU's model and the RBC(Risk Based Capital) system in U.S. and Japan. Finally, this paper suggests a more specific and reasonable solvency margin system to be developed in Korea.

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NUMERICAL INVESTIGATION OF THE SPREADING AND HEAT TRANSFER CHARACTERISTICS OF EX-VESSEL CORE MELT

  • Ye, In-Soo;Kim, Jeongeun Alice;Ryu, Changkook;Ha, Kwang Soon;Kim, Hwan Yeol;Song, Jinho
    • Nuclear Engineering and Technology
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    • v.45 no.1
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    • pp.21-28
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    • 2013
  • The flow and heat transfer characteristics of the ex-vessel core melt (corium) were investigated using a commercial CFD code along with the experimental data on the spreading of corium available in the literature (VULCANO VE-U7 test). In the numerical simulation of the unsteady two-phase flow, the volume-of-fluid model was applied for the spreading and interfacial surface formation of corium with the surrounding air. The effects of the key parameters were evaluated for the corium spreading, including the radiation, decay heat, temperature-dependent viscosity and initial temperature of corium. The results showed a reasonable trend of corium progression influenced by the changes in the radiation, decay heat, temperature-dependent viscosity and initial temperature of corium. The modeling of the viscosity appropriate for corium and the radiative heat transfer was critical, since the front progression and temperature profiles were strongly dependent on the models. Further development is required for the code to consider the formation of crust on the surfaces of corium and the interaction with the substrate.

INVESTIGATION OF ACTIVATED CARBON ADSORBENT ELECTRODE FOR ELECTROSORPTION-BASED URANIUM EXTRACTION FROM SEAWATER

  • ISMAIL, AZNAN FAZLI;YIM, MAN-SUNG
    • Nuclear Engineering and Technology
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    • v.47 no.5
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    • pp.579-587
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    • 2015
  • To support the use of nuclear power as a sustainable electric energy generating technology, long-term supply of uranium is very important. The objective of this research is to investigate the use of new adsorbent material for cost effective uranium extraction from seawater. An activated carbon-based adsorbent material is developed and tested through an electrosorption technique in this research. Adsorption of uranium from seawater by activated carbon electrodes was investigated through electrosorption experiments up to 300 minutes by changing positive potentials from +0.2V to +0.8V (vs. Ag/AgCl). Uranium adsorption by the activated carbon electrode developed in this research reached up to 3.4 g-U/kg-adsorbent material, which is comparable with the performance of amidoxime-based adsorbent materials. Electrosorption of uranium ions from seawater was found to be most favorable at +0.4V (vs. Ag/AgCl). The cost of chemicals and materials in the present research was compared with that of the amidoxime-based approach as part of the engineering feasibility examination.

BEHAVIORS OF MOLYBDENUM IN UO2 FUEL MATRIX

  • Ha, Yeong-Keong;Kim, Jong-Goo;Park, Yang-Soon;Park, Soon-Dal;Song, Kyu-Seok
    • Nuclear Engineering and Technology
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    • v.43 no.3
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    • pp.309-316
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    • 2011
  • Molybdenum is the most abundant fission product since its fission yield is equivalent to that of xenon, and it has a very special role in the chemistry of nuclear fuel because it influences the oxygen potential of $UO_2$ fuel. In this study, the distribution of molybdenum in spent $UO_2$ fuel specimens with 33.3, 41.0 and 57.6 GWd/tU burnup was measured by a LA-ICP-MS system and the reproducibility of the measured data was obtained. The Mo distribution was almost constant along the radius of a fuel except an increase at the periphery of the fuel. It showed a drop in reproducibility with relatively high deviation of measured values for the highest burnup fuel. To explain this, the state of molybdenum in a $UO_2$ matrix and its effect on the oxidation behavior of $UO_2$ were investigated. The low reproducibility was explained by the segregation of molybdenum, and the inhibition of oxidation by the molybdenum was also observed.