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New coefficients to find natural period of elevated tanks considering fluid-structure-soil interaction effects

  • Maedeh, Pouyan Abbasi;Ghanbari, Ali;Wu, Wei
    • Geomechanics and Engineering
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    • v.12 no.6
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    • pp.949-963
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    • 2017
  • The main purpose of the current study is to develop the new coefficients for consideration of soil-structure interaction effects to find the elevated tank natural period. Most of the recommended relations to find the natural period just assumed the fixed base condition of elevated tank systems and the soil effects on the natural period are neglected. Two different analytical systems considering soil-structure- fluid interaction effects are recommended in the current study. Achieved results of natural impulsive and convective period, concluded from mentioned models are compared with the results of a numerical model. Two different sets of new coefficients for impulsive and convective periods are developed. The values of the developed coefficients directly depend to soil stiffness values. Additional results show that the soil stiffness not only has significant effects on natural period but also it is effective on liquid sloshing wave height. Both frequency content and soil stiffness have significant effects on the values of liquid wave height.

Field Observation and Numerical Modeling for Secondary Undulation (항만 부진동에 관한 현장관측 및 수치실험)

  • 김규한;김덕중;배기성
    • Journal of Ocean Engineering and Technology
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    • v.16 no.2
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    • pp.27-31
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    • 2002
  • The purpose of this study is to investigate the variation of resonance that is possible caused by construction of new port in a practical sea area between the existing port and the new one. The research of amplification that of the sea area was accomplished for the variation of resonance. In this study, long period wave that is observed continuously in the practical sea area was analyzed, and then secondary undulation was reproduced by numerical analysis. As a result of numerical analysis, the first mode resonant periods in the existing port is 640sec, and in the new one is 500sec. On the other hand, we know there is long period wave of 500sec from analyzation of field datas. Because that period this period is the resonant period in the new port. There is also the possibility of secondary undulation cause of resonant.

A Study of Names Used on Seals in the Age of Civil Wars in China (중국전국시대 인장(印章)에 반영된 인명 특징 연구)

  • Moon, Byung-soon
    • Cross-Cultural Studies
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    • v.19
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    • pp.25-38
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    • 2010
  • The "Name" is not only representative of a person but also a cultural heritage containing national cultures. Therefore, we can easily find some cultural value from the square inch sized seal texts. This article is a comprehensive study of the characteristics of names appeared on the seals in the Warring States Period. In the Warring States Period, single name is generally used for naming and this style can be divided into 13 categories. Except unavoidable cases, such as using the name of place, the name of person or the reason of physical characteristics, using double name is very rare and this style can be categorized by 8 kinds. In result, using double name is defined as a fringe method of naming in the Warring States Period. In addition, we can find a big difference between the names of Warring States Period and those of Post-Qin and Han Dynasties in the structural aspects. In conclusion, understanding of the characteristics of names from the Warring States Period can be a great help to better understanding of ancient books and unearthed documents.

Period changes in the Intermediate Polar MU Camelopardalis

  • Park, Jiwon;Yoon, Jho-Na;Kim, Yonggi;Andronov, I.L.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.89.1-89.1
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    • 2015
  • Period changes found in the 10 years CCD BVR photometry data (2005 - 2014) of the Intermediate Polar MU Cam will be discussed. The timings of extrema of the data are determined and the new ephemeris for the spin period and orbital period have been calculated by using multi-periodic approximation as follows: BJD(orb)=2454085.46(19)+0.19664 $10(26){\cdot}E$ and BJD(spin)=2454085.50725(91)+0.013740942(13) ${\cdot}$ $E-1.51(10){\times}10^{-12}{\cdot}E^2$. The O-C diagram shows an increasing of the spin period as $P=-2.20(14){\cdot}10^{-12}s/s$. It is also found in MU Cam that the white dwarf's rotation seems to be switched from a state of spin-down to spin-up by the white dwarf's equilibrium spin period in 2005.

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Studies on the Ovarian Respones of Rabbits Superovulated Repeatedly (반복과배란토끼의 난소반응에 관한 연구)

  • 한기영
    • Korean Journal of Animal Reproduction
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    • v.8 no.1
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    • pp.36-45
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    • 1984
  • This study was carried out to investigate the changes in ovary in repeatedly superovulated rabbits. A total of 57 New Zealand White and Californian, 25 mature virgin and 32 immature does were used in this study. For induction of repeated superovulation, PMSG and HCG were injected at 17-day and 30-day intervals for mature does and 17-day intervals for immature ones. The repeatedly superovulated does at 17-day intervals were induced luteolysis of pseudopregnant corpus luteum with PGF2${\alpha}$ on Day 8 to 9 p.c. The effect of repeated superovulation on reproductive organs was investigated on Day 3 p.c. in mature does and on Day 3 and 6 p.c. in immature ones, respectively. 1. In mature virgin does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 7.0 and 5.0 at 17-day intervals and 13.4 and 6.0 at 30-day intervals, respectively. These numbers were statistically similar to 9.5 ovulation points in the control. However, there were less (p<0.05) ovulation points in those periods compared with 22.1 ovulation points in the 1st superovulation period. 2. In immature does, the number of ovulation points in the 2nd and 3rd superovulation period averaged 5.3 and 2.3, respectively. These numbers were significantly (p<0.05) decreased than 17.1 ovulation points in the 1st periods. The number of ovulation points in the 2nd superovulation period was similar to that in the control, but there was a significant (p<0.05) decrease in the number of ovulation points in the 3rd period as compared to the control. 3. In mature virgin does, the number of visible normal and hemorrhagic follicles (>1.0mm diameter) on day 3 p.c. averaged 19.1 and 8.9 in the 1st superovulation period, respectively. In the 2nd 3rd superovulation period, the number of normal follicles averaged 8.3 and 15.5 at 17-day intervals and 17.8 and 14.5 at 30-day intervals. The number of hemorrhagic follicles in the 2nd and 3rd superovulation period averaged 6.3 and 2.0 at 17-day intervals and 5.2 and 7.8 at 30-day intervals, respectively. There was a slight decrease, although not significant, in the number of normal and hemorrhagic follicles in the 2nd and 3rd period at 17-day intervals compared to that in the 1st period. 4. In immature does, the number of visible normal follicles on day 3 and day 6 p.c. in the 1st superovulation period averaged 27:3 and 26.1, respectively. The follicles on day 3 p.c. tended to increase slightly more than that in the cortrol, but the average number of normal follicles on day 6 p.c. did not differ from that in the control. The number of visible hemorrhagic follicles on day 3 and day 6 p.c. in the 1st of follicles in the 1st superovulation period average 10.2 and 9.9, respectively. There was a slight increase in the number of follicles in the 1st period compared to that in the control. In the 2nd and 3rd superovulation period, the number of normal follicles revealed a slight decrease in the 3rd period, but the number of hemorrhagic follicles was not different between periods. 5. The number of growing follicles with incipient intral formation on day 3 p.c. in mature does of the 1st superovulaton period average 29.7 and the average number of growing follicles in the 3rd period was 26.7 at 17-day intervals and 31.0 at 30-day intervals, respectively. These numbers did not differ from that in the control. In immature does, the number of growing follicles averaged 57.7, 45.0 and 59.3 in the 1st, 2nd and 3rd superovulation period, respectively. There was a slight but not significant decrease in the number of growing follicles in the 3rd period compared to that in the control.

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A Study on Job Characteristics of Foodcoordinator (푸드 코디네이터의 직무에 관한 기초 연구)

  • Hwang, Jae-Sun;Joo, Na-Mi;Han, Young-Sil
    • Journal of the Korean Society of Food Culture
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    • v.19 no.6
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    • pp.611-619
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    • 2004
  • This study was conducted to investigate the job characteristics of foodcoordinator. 34.56% of subjects have the part of food as a speciality in college or University. 50.67% of subjects don't have any licence which is related with food. 30.67% of subjects have 1-3year or under career in the food part. Upon investigation the educational period by the period of career in food part, Subjects who had 5 year over career in the food part have 60.34month educational period. Upon investigation the speciality in college or University by the period of career in food part, 58.33% of 5 year over career in the food part respondents have food speciality in college or University. As the period of career in food was increased, the importance of cooking was increased.

Period doubling of the nonlinear dynamical system of an electrostatically actuated micro-cantilever

  • Chen, Y.M.;Liu, J.K.
    • Smart Structures and Systems
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    • v.14 no.5
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    • pp.743-763
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    • 2014
  • The paper presents an investigation of the nonlinear dynamical system of an electrostatically actuated micro-cantilever by the incremental harmonic balance (IHB) method. An efficient approach is proposed to tackle the difficulty in expanding the nonlinear terms into truncated Fourier series. With the help of this approach, periodic and multi-periodic solutions are obtained by the IHB method. Numerical examples show that the IHB solutions, provided as many as harmonics are taken into account, are in excellent agreement with numerical results. In addition, an iterative algorithm is suggested to accurately determine period doubling bifurcation points. The route to chaos via period doublings starting from the period-1 or period-3 solution are analyzed according to the Floquet and the Feigenbaum theories.

Seismic Fragility Analysis Utilizing PDF Interpolation Technique (확률밀도함수 보간에 의한 교량의 지진취약도 분석)

  • ;;;Shigeru Kushiyama
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.495-502
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    • 2003
  • This study proposed the Probability Density Function (PDF) interpolation technique to evaluate the seismic fragility curves as a function of the return period. Seismic fragility curves have been developed as a function of seismic intensities such as peak ground acceleration, peak pound velocity, and pseudo-velocity spectrum. The return period of design earthquakes, however, can be more useful among those seismic intensity measurements, because the seismic hazard curves are generally represented with a return period of design earthquakes and the seismic design codes also require to consider the return period of design earthquake spectrum for a specific site. In this respect the PDF interpolation technique is proposed to evaluate the seismic fragility curves as a function of return period. Seismic fragility curves based on the return period are compared with ones based on the peak ground acceleration for the bridge model.

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OSCILLATORY THERMAL CONVECTION IN A HORIZONTAL ANNULUS (수평 환형 공간에서의 진동하는 열대류)

  • Yoo Joo-Sik
    • Journal of computational fluids engineering
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    • v.11 no.2 s.33
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    • pp.49-55
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    • 2006
  • This study investigates the oscillatory thermal convection of a fluid with Pr=0.02 in a wide-gap horizontal annulus with constant heat flux inner wall. When Pr=0.02, dual steady-state flows are not found. After the first Hopf bifurcation from a steady to a time-periodic flow, five successive period-doubling bifurcations are recorded before chaos. The power spectrum shows the $period-2^4\;and\;2^5$ flows clearly, and a window of period $3{\times}2^3$ flow is found in the chaotic regime. The approximate value of the Feigenbaum number for the last three period-doubling bifurcations is 4.76. The transition route to chaos of the present simulations is consistent with the period-doubling route of Feigenbaum.

Evaluation of carbonation service life of slag blended concrete considering climate changes

  • Wang, Xiao-Yong;Luan, Yao
    • Computers and Concrete
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    • v.21 no.4
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    • pp.419-429
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    • 2018
  • Climate changes, such as increasing of $CO_2$ concentration and global warming, will impact on the carbonation service life of concrete structures. Moreover, slag blended concrete has a lower carbonation resistance than control concrete. This study presents a probabilistic numerical procedure for evaluating the impact of climate change on carbonation service life of slag blended concrete. This numerical procedure considers both corrosion initiation period and corrosion propagation period. First, in corrosion initiation period, by using an integrated hydration-carbonation model, the amount of carbonatable substances, porosity, and carbonation depth are calculated. The probability of corrosion initiation is determined through Monte Carlo method. Second, in corrosion propagation period, a probabilistic model is proposed to calculate the critical corrosion degree at surface cracking, the probability of surface cracking, and service life. Third, based on the service life in corrosion initiation period and corrosion propagation period, the whole service life is calculated. The analysis shows that for concrete structures with 50 years service life, after considering climate changes, the service life reduces about 7%.