• 제목/요약/키워드: Natural Experiment

검색결과 2,550건 처리시간 0.028초

곡선보의 모우드 해석 (Modal Analysis of Curved Beam.)

  • 김영문;유기표
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2000년도 가을 학술발표회논문집
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    • pp.349-354
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    • 2000
  • The modal analysis based on deformations is the method to drived dynamic responsed from superposition of natural frequency and mode shape. In order to free vibration analysis of the structures, Aluminum-made model is used in experiment. The dynamic characteristic of the structures are determined from acceleration measurements using impulse hammer. Experimenrt input and output signal are derive from impact hammer and the one accerometer. This paper present three methods for calculating the natural frequencies and mode shapes of the structure with theory value and finite element analysis, experiment. The results were good approximated about natural frequency and mode shape.

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Evaluation of polyherbal formulation and synthetic choline chloride on choline deficiency model in broilers: implications on zootechnical parameters, serum biochemistry and liver histopathology

  • Selvam, Ramasamy;Saravanakumar, Marimuthu;Suresh, Subramaniyam;Chandrasekeran, CV;Prashanth, D'Souza
    • Asian-Australasian Journal of Animal Sciences
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    • 제31권11호
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    • pp.1795-1806
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    • 2018
  • Objective: The study was designed to establish choline deficiency model (CDM) in broilers for evaluating efficacy of polyherbal formulation (PHF) in comparison with synthetic choline chloride (SCC). Methods: A total of 2,550 one-day-old Cobb 430 broiler chicks were randomly assigned to different groups in three experiments. In experiment 1, G1 and G2 served as normal controls and were fed a basal diet with 100% soybean meal (SBM) as a major protein source supplemented with and without SCC, respectively. In G3, G4, G5, and G6 groups, SBM was replaced at 25%, 50%, 75%, and 100% by soy protein isolate (SPI) to induce a graded level of choline deficiency. In experiment 2, PHF (500 and 1,000 g/ton) in comparison with SCC (1,000 g/ton) were evaluated. In experiment 3, dose-response of PHF (200, 400, and 500 g/ton) with SCC (400 g/ton) was determined. Results: Replacement of SBM by SPI produced a linear decrease in body weight gain (BWG) with a poor feed conversion ratio (FCR). 25% SBM replacement by SPI yielded an optimum negative impact on BWG and FCR; hence, it is considered for further studies. In experiment 2, PHF (500 and 1,000 g/ton) and SCC (1,000 g/ton) showed a similar performance in BWG, FCR and relative liver weight. In experiment 3, PHF produced an optimum efficacy at 400 g/ton and was comparable to SCC in the restoration of serum aspartate aminotransferase activity, abdominal fat, breast muscle lipid content and liver histopathological abnormalities. Conclusion: Replacement of SBM by SPI caused choline deficiency characterised by worsening of BWG, FCR, elevation in liver enzymes and histopathological changes indicating fatty liver. CDM was found valid for evaluating SCC and PHF. It is concluded that PHF has the potential to mimic biological activities of SCC through the restoration of negative effects caused by CDM.

Post Test Analysis to Natural Circulation Experiment on the BETHSY Facility Using the MARS 1.4 Code

  • Chung, Young-Jong;Kim, Hee-Cheol;Chang, Moon-Hee
    • Nuclear Engineering and Technology
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    • 제33권6호
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    • pp.638-651
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    • 2001
  • The present study is to assess the applicability of the best-estimate thermal-hydraulic code, MARS 1.4, for the analysis of thermal-hydraulic behavior in PWRs during natural circulation conditions. The code simulates a natural circulation test, BETHSY test 4. la, which was conducted on the integral test facility of BETHSY. The test represented the cooling states of the primary cooling system under single-phase natural circulation, two-phase natural circulation and the reflux condensation mode with conditions corresponding to the residual power, 2% of the rated core power value and 6.8 MPa at the secondary system. Based on MARS 1.4 calculations, the major thermal-hydraulic behaviors during natural circulation are evaluated and the differences between the experimental data and calculated results are identified. The calculated results show generally good behavior with regard to the experimental results; the region of single-phase natural circulation is 100-92% of the initial mass inventory, two-phase natural circulation is 84-63 %, and the reflux condensation mode occurred below 58 %. U-tubes empty and the core uncovery are obtained at 39 % and 34 % of the initial mass inventory, respectively.

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Analytical and experimental study on natural sloshing frequencies in annular cylindrical tank with a bottom gap

  • Lee, H.W.;Jeon, S.H.;Cho, J.R.;Seo, M.W.;Jeon, W.B.
    • Structural Engineering and Mechanics
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    • 제57권5호
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    • pp.877-895
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    • 2016
  • This paper is concerned with the analytical derivation of natural sloshing frequencies of liquid in annular cylindrical tank and its verification by experiment. The whole liquid domain is divided into three simple sub-regions, and the region-wise linearized velocity potentials are derived by the separation of variables. Two sets of matrix equations for solving the natural sloshing frequencies are derived by enforcing the boundary conditions and the continuity conditions at the interfaces between sub-regions. In addition, the natural sloshing frequencies are measured by experiment and the numerical accuracy of the proposed analytical method is verified through the comparison between the analytical and experimental results. It is confirmed that the present analytical method provides the fundamental sloshing frequencies which are in an excellent agreement with the experiment. As well, the effects of the tank radial gap, the bottom flow gap and the liquid fill height on the fundamental sloshing frequency are parametrically investigated.

기부참여행동에 대한 현장실험 연구(Natural Field Experiment) : 구세군 자선냄비 모금을 활용한 분석 (A Natural Field Experiment on Citizens' Giving Behavior: Analysis on Red Kettle Campaign of Salvation Army)

  • 강철희;박소현
    • 사회복지연구
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    • 제47권3호
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    • pp.61-84
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    • 2016
  • 본 연구는 실제 기부 현장에서 타인의 기부행동 정보와 개인의 기부행동 간에 어떠한 관련성이 있는지를 탐색해보고자 하였다. 이를 위해 한국구세군의 협조를 얻어 2년에 걸친 구세군 자선냄비 현장모금 실험을 실시하였으며, 타인의 기부행동에 대한 정보는 돈을 가득 채운 통, 돈을 채우지 않은 통, 안이 보이지 않는 통의 세 가지 수준으로 제공하였다. 분산분석 결과, 1차년도와 2차년도 실험 모두 통별 기부인원 및 1인당 기부금액에 있어 통계적으로 유의한 차이가 없는 것으로 나타났다. 외생변수의 영향력을 고려한 회귀분석 결과에서도 통에 따른 기부인원 및 기부금액의 차이가 나타나지 않았다. 이같은 결과는 타인의 기부행동 정보가 개인의 기부행동에 영향을 주지 않음을 시사하는 것이라 할 수 있다. 본 연구는 새로운 연구방법을 적용하여 시민들의 실제적 기부행동에 대한 이해를 확장시키고 향후 후속 연구를 위한 발판을 제공한다는 점에서 의의를 지닌다.

Evapotranspiration and Grain Yield in Responses to Different Soil Water Conditions in Soybean

  • Yang, Jae-Hwang;Kim, Wook-Han;Seong, Rak-Chun;Hong, Byung-Hee
    • 한국작물학회지
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    • 제45권4호
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    • pp.241-244
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    • 2000
  • This experiment was conducted to evaluate the effect on evapotranspiration and yield of soybean according to different soil water conditions, and to find the optimum time and amount for irrigation in soybean cultivation. The difference between potential evapotranspiration (PET) and maximum evapotranspiration (MET) during growing season of soybean planted in lysimeter was higher during reproductive stage than during vegetative one. The maximum crop coefficient was obtained at beginning seed stage of soybean. Soil water coefficient of irrigation treatment was higher than that of non-irrigation treatment during soybean growth stage in field experiment. Grain yield was highest in lysimeter due to its high water use efficiency and evapotranspiration rate.

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A Study on the General Characteristics and Instrumental Analysis of Natural Omija Extract

  • Sung, Ki-Chun;Kim, Ki-Jun;Kim, Yong-Ryul;Nam, Sang-Sung
    • 한국응용과학기술학회지
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    • 제30권2호
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    • pp.225-232
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    • 2013
  • Omija component was known to possess natural odor, taste, color, and various general characteristics. Omija extraction was extracted using ethanol as a solvent. Omija extract showed a red-purple color of some viscous liquid state. Some conclusions from natural Omija extract were obtained as follow. The result of antimicrobial experiment to add Omija extract, the number of microbial population showed negative reaction from 3 days after it cultivated. This phenomenon could confirm that Omija component affected to antimicrobial effect. The result of dyeing experiment to add Omija extract, fiber dyeing effect showed with some ivory color after dyed to cotton and silk. Also, this phenomenon could confirm that Omija component affected to natural dyeing effect from observated dye state with biological microscope(BM). The result of instrumental analysis, inorganic components of K(109.60ppm), Na(3.500ppm), Ca(1.205ppm), Mg(0.900ppm), Li(0.350ppm), Si(0.380ppm), Cu(0.250ppm), Fe(0.125ppm), Zn(0.090ppm), etcs from Omija were ascertained with ICP/OES, and organic components of benzene(10.808), borny lacetate(11.289), phenol(14.183), ${\beta}$-terpinene(15.840), ${\alpha}$-terpinolene(17.616) etcs from Omija were ascertained with GC/MSD.

Experimental validation of simulating natural circulation of liquid metal using water

  • Lee, Min Ho;Jerng, Dong Wook;Bang, In Cheol
    • Nuclear Engineering and Technology
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    • 제52권9호
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    • pp.1963-1973
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    • 2020
  • Liquid metal-cooled reactors use various passive safety systems driven by natural circulation. Investigating these safety systems experimentally is more advantageous by using a simulant. Although numerous experimental approaches have been applied to natural circulation-driven passive safety systems using simulants, there has been no clear validation of the similarity law. To validate the similarity law experimentally, SINCRO-V experiment was conducted using Wood's metal and water for simulant of the Wood's metal. A pair of SINCRO-V facilities with length-scale ratio of 14.1:1 for identical Bo' was investigated, which was the main similarity parameter in temperature field simulation. In the experimental range of 0.2-1.0% of decay heat, the temperature distribution characteristics of the small water facility were very similar to that of the large Wood's metal facility. The temperature of the Wood's metal predicted by the water experiment showed good agreement with the actual Wood's metal temperature. Despite some error factors like discordance of Gr' and property change along the temperature, the water experiment predicted the Wood's metal temperature with an error of 27%. The validity of the similarity law was confirmed by the SINCRO-V experiments.