• 제목/요약/키워드: Ground state

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부지 고유의 지반 거동평가 (Evaluation of Site Specific Ground Response)

  • 김동수;이진선;윤종구
    • 한국지진공학회논문집
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    • 제3권4호
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    • pp.1-10
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    • 1999
  • 지진 시 지반의 자유장 운동은 국지적 지반조건에 의하여 크게 영향을 받으며 내진설계에 앞서 지반조건을 고려한 부지응답특성평가를 수행하여야 한다. 본 논문은 부지고유의 지반거동 평가를 위하여 필요한 절차를 국내 내진기준과 외국의 기술현황 조사를 바탕으로 제안하였다. 부지응답특성 평가의 개요를 설명하고 1차원 등가선형 해석에 필요한 지반자료 획득을 위한 지반조사계획 기반조사기법, 저변형율 및 고변형율 영역에서의 지반의 변형거동특성, 현장 및 실내시험결과를 이용한 부지특성평가방법들을 제안하였다 또한 제안된 절차를 따라 수행된 인천 지역의 부지특성평가방법들을 제안하였다 또한 제안된 절차를 따라 수행된 인천 지역의 부지응답특성평가 예를 포함하였다.

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PROBABILISTIC SEISMIC ASSESSMENT OF BASE-ISOLATED NPPS SUBJECTED TO STRONG GROUND MOTIONS OF TOHOKU EARTHQUAKE

  • Ali, Ahmer;Hayah, Nadin Abu;Kim, Dookie;Cho, Ung Gook
    • Nuclear Engineering and Technology
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    • 제46권5호
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    • pp.699-706
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    • 2014
  • The probabilistic seismic performance of a standard Korean nuclear power plant (NPP) with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA) of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA) as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

지상 기동 및 고정 환경하 고장률 특성 분석 (Failure Rate Characteristics Analysis under Ground Mobile and Ground Fixed Environments)

  • 윤희성;정다운;윤종성;이승헌
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제11권3호
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    • pp.293-303
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    • 2011
  • Reliability Prediction using MIL-HDBK-217F has some restrictions due to its one modeling basis. One of the restrictions is caused by selecting one operating environment of a system, which is chosen regardless of its detailed conditions, e.g., external impact and vibration. Especially, an equipment, which is installed on a mobile vehicle though its movement is quasi-static, is controversial to designate its environment as ground mobile($G_M$), rather than ground fixed($G_F$). In this paper, failure rates were compared, which are computed using several moving time rates to total operating time. RiAC-HDBK-217Plus was used as the basic calculation model. In addition, $G_F$ conditioned failure rate was evaluated by comparing with that under $G_M$ environment but fixed state.

Antimicrobial Effect of Buffered Sodium Citrate (BSC) on Foodborne Pathogens in Liquid Media and Ground Beef

  • Ryu, Si-Hyun;Fung, Daniel -Y. C.
    • Preventive Nutrition and Food Science
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    • 제15권3호
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    • pp.239-243
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    • 2010
  • The antimicrobial effects of a commercially available, buffered sodium citrate (BSC) were evaluated for the reduction of total aerobic bacteria count, Salmonella Typhimurium, Escherichia coli O157:H7, Listeria monocytogenes and Staphylococcus aureus in a liquid medium and ground beef. BSC at 0, 1, 2 and 4.8% (wt/vol) or 0, 3, and 4.8% (wt/wt) was mixed into inoculated brain heart infusion (BHI) broth and ground beef (80% lean), respectively. BSC at concentrations of 1 and 2% did not inhibit growth of the pathogens tested in BHI broth. E. coli O157:H7 in BHI broth with 4.8% BSC was significantly reduced (p<0.05) by 3~4 log CFU/mL compared with the control for up to 4 days. At 4.8%, BSC treatment of ground beef most significantly reduced (p<0.05) total aerobic count and E. coli O157:H7 by 2.1 and 2.0 log CFU/g, respectively. This study indicates that the legally allowable level of 1.3% (wt/wt) BSC is not effective for reducing the pathogens tested in ground beef stored at $7^{\circ}C$.

Jet-grouting in ground improvement and rotary grouting pile installation: Theoretical analysis

  • Wang, You;Li, Lin;Li, Jingpei;Sun, De'an
    • Geomechanics and Engineering
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    • 제21권3호
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    • pp.279-288
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    • 2020
  • The permeation grouting is a commonly used technique to improve the engineering geology condition of the soft ground. It is of great significance to predict the permeation range of the grout so as to ensure the effects of grouting. This paper conducts a theoretical analysis of jet-grouting effects in ground improvement and rotary grouting pile installation by utilizing deformation-permeation coupled poroelastic solutions based on Biot's theory and Laplace-Fourier integral transform technique. The exponential function and the intermittent trigonometric function are chosen to represent time-dependent grouting pressure usually encountered in ground improvement and rotary grouting pile installation process, respectively. The results, including the radial displacement, the hoop stress, the excess pore fluid pressure, the radial discharge, and the permeation radius of grout, are presented for different grouting time, radial positions and grouting lengths. Parametric study is conducted to explore the effects of variation of the exponent in the exponential grouting pressure-time relationship on grouting-induced responses. It is expected that the proposed solutions can be used to estimate the permeation range of grouting in ground improvement and rotary grouting pile installation.

Evaluation of ground motion scaling methods on drift demands of energy-based plastic designed steel frames under near-fault pulse-type earthquakes

  • Ganjavi, Behnoud;Hadinejad, Amirali;Jafarieh, Amir Hossein
    • Steel and Composite Structures
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    • 제32권1호
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    • pp.91-110
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    • 2019
  • In the present study, the effects of six different ground motion scaling methods on inelastic response of nonlinear steel moment frames (SMFs) are studied. The frames were designed using energy-based PBPD approach with the design concept using pre-selected target drift and yield mechanism as performance limit state. Two target spectrums are considered: maximum credible earthquake spectrum (MCE) and design response spectrum (DRS). In order to investigate the effects of ground motion scaling methods on the response of the structures, totally 3216 nonlinear models including three frames with 4, 8 and 16 stories are designed using PBPD approach and then they are subjected to ensembles of ground motions including 42 far-fault and 90 near-fault pulse-type records which were scaled using the six different scaling methods in accordance to the two aforementioned target spectrums. The distributions of maximum inter-story drift over the height of the structures are computed and compared. Finally, the efficiency and reliability of each ground motion scaling method to estimate the maximum nonlinear inter-story drift of special steel moment frames designed by energy-based PBPD approach are statistically investigated, and the most suitable scaling methods with the lowest dispersion for two groups of earthquake ground motions are introduced.

3상 일괄형 Pipe Type HTS 케이블의 정상 및 과도상태 해석 (Steady and Transient State Analysis on Three Phase-in One Enclosure Type HTS Cable)

  • 장주영;이종범;김용갑
    • 전기학회논문지
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    • 제59권10호
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    • pp.1748-1753
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    • 2010
  • This paper suggests an improved technique to establish the modeling regarding steady and transient state on three phase-in one cryostat type HTS(High Temperature Superconducting) cable. The proposed modeling is established using EMTP/ATPDraw and TACS and MODELS provided by that. It has higher accuracy than the conventional method, as the actual HTS cable is modelled. Steady and transient state analysis performed by EMTP/ATPDraw calculate the current of conductor, shield and former, respectively. In case of the transient state modeled quench state occurred by a single line-to-ground fault, current of conductor shield and former are also calculated, respectively. Especially, various fault resistances and angles are considered to improve the reliability during transient state analysis. Analysis results reveal that the proposed technique improves the accuracy of modeling.

Photophysical Behaviors of Biphenylcarboxylic Acids in Various Solvents; Excited-State Geometry Change and Intramolecular Charge Transfer

  • Yoon Minjoong;Cho Dae Won;Lee Jae Young
    • Bulletin of the Korean Chemical Society
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    • 제13권6호
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    • pp.613-620
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    • 1992
  • The solvent-dependent photophysical properties of 2-biphenylcarboxylic acid (2BPCA) and 4-biphenylcarboxylic acid(4BPCA), which have a pre-twisted conformation in the ground state, have been investigated. The fluorescence spectra of 4BPCA show vibrational structure with a non-mirror image to the absorption spectra in nonpolar solvent while those of 2BPCA show no structure even in nonpolar solvents. As the solvent polarity increases, the fluorescence spectra become diffuse and broad with a strong red shift resulting in the large Stokes shift. The large fluorescence Stokes shift of BPCA's in polar solvent is also partially due to an intramolecular charge transfer (ICT) interaction in the excited state, as demonstrated by the large dipole moment in the excited state (7.6-10.6 D). The fluorescence decay behaviors of BPCA's (decay-times and their pre-exponential factors) also depend on solvent polarity in agreement with the solvent-dependent properties of the steady-state fluorecence. The data have been discussed in terms of change in the excited-state potential energy surface with respect to change of the dihedral angle of biphenyl moiety.

The Impact of State Budget Revenue on Economic Growth: A Case of Vietnam

  • NGUYEN, Hieu Huu
    • The Journal of Asian Finance, Economics and Business
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    • 제6권4호
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    • pp.99-107
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    • 2019
  • This paper is intended to study the relationship between state budget revenue and economic growth in Vietnam. The ordinary least-squares regression method is used with secondary data collected from General Statistics Office of Vietnam in the period of 2000-2017. Vietnamese state budget revenue includes domestic revenue (excluding oil revenue), oil revenue, custom duty revenue, and grants. The testing result shows that the state budget revenue has a positive correlation with economic growth of Vietnam. However, the components of state budget revenue have different levels of impact on the economy. Domestic revenue and oil revenue are statistically significant and have a positive effect on the economy, while the impact of custom duty revenue and grants on the economy is invisible. Vietnamese state budget revenue should be restructured toward the sustainability and by way of boosting the economy, specifically: (1) Increase the proportion of domestic revenue to state budget revenue and domestic revenue should be based on the ground of production and business activities rather than collection from state-owned assets; (2) Reduce the proportion of custom duty revenue and grants to state budget revenue; (3) Keep the volume and ratio of oil revenue in state budget revenue at an appropriate proportion.

고로슬래그 분말을 혼화재로 사용한 고강도콘크리트의 기초적 성질에 대한 연구 (A Study on the Fundamental Properties of High-Strength Concrete Using Ground Granulated Blast-Furnace Slag as an Admixture)

  • 문한영;최연왕;문대중;송용규
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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    • pp.30-35
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    • 1995
  • This paper presents fundamental experiment for the properties of high performance concrete in its fresh and hardened state made with ground granulated blast-furnace (GGBF) slag. The result is that the effect of decreasing xoncrete temperature is to the mixing ratio of GGBF slag, but it presents disadvantage in the slump loss phase. In addition to, we know that the splitting tensile strength, compressive strength and elastic modulus of concrete mixed with high fineness GGBF slag are increased at age 28days.

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