• Title/Summary/Keyword: Restraining effect

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Influence of Tank Inner Side Dielectric Coating on the Particle Behaviour and Flashover Voltage in SF\ulcorner Gas Insulated System

  • Lee, Bang-Wook;Koo, Ja-Yoon
    • Journal of Electrical Engineering and information Science
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    • v.2 no.3
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    • pp.77-81
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    • 1997
  • In his work, the influence of wire type conducting particles on the insulation reliability of GIS has been systematically investigated when the epoxy resin based dielectric coating was made on he inner side of outer electrode. For this purpose, coaxial cylinder-type electrode was adopted in 362 kV chamber and various sizes of Cu conducting particle were used under different gas pressures. In order to elucidate the coating effect on the gas insulation, different thickness of dielectric coating has been considered and then the lift-off voltage and flashover voltages have been measured. The results shown that the dielectric coating has a remarkable influence by restraining the movement of particle in GIS system, and thus GIS insulation reliability is noticeably improved.

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The Need for Research about Buckling Strength of Arch and Beam (보와 아치의 좌굴강도에 관한 연구의 필요성)

  • Lim, Nam-Hyoung;Lee, Chin-Ok;Ryu, Hyo-Jin;Lee, Woo-Chul;Koo, So-Yeun
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.223-226
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    • 2007
  • In current specification, modification factor(B) for web-tapered beam is used to account for the stress gradient and the restraining effect for adjacent spans. However, because these effects are considered together in modification factor, this paper revaluate the accuracy of the modification factor used in current specification. Also this paper investigate the flexural torsional buckling strength of laterally fixed thin-walled arch with doubly symmetric section using the analytical and numerical method. From this investigate the concept of effective length to consider the out-of-plane boundary condition for straight column or beam is not applicate for the flexural-torsional buckling of laterally fixed arches.

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Analysis of Coupled Horizontal-Torsional Vibrations of Container Ships (콘테이너선의 수평-비틂연성진동 해석)

  • K.C.,Kim;S.J.,Kim
    • Bulletin of the Society of Naval Architects of Korea
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    • v.23 no.4
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    • pp.1-10
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    • 1986
  • A container ship, due to wide hatch openings, has characteristics of poor torsional rigidity, strong coupling of horizontal-torsional modes and significant discontinuity in the longitudinal variation of hull sections. In the mathematical formulation of the problem the hull is modeled as a beam and the transfer matrix method is utilized. The cross decks between cargo hatch opening are separated from the main hull and regarded as equivalent springs restraining torsion of hull. The effect of shear deformation of ship-side plating on torsion is taken into account in addition to St. Venant's and bending torsional rigidities. Compatibility requirements at cross section discontinuity are approximately considered. Developing the practical calculation procedure and the computer programs for application to an actual ship, some parametric studies on modeling methods of the cross deck, the compatibility condition, added-mass center etc. are out for the purpose of comparison.

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Practical design guidlines for semi-continuous composite braced frames

  • Liew, J.Y. Richard;Looi, K.L.;Uy, Brian
    • Steel and Composite Structures
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    • v.1 no.2
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    • pp.213-230
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    • 2001
  • This paper presents a simplified approach for the design of semi-continuous composite beams in braced frames, where specific attention is given to the effect of joint rotational stiffness. A simple composite beam model is proposed incorporating the effects of semi-rigid end connections and the nonprismatic properties of a 'cracked' steel-concrete beam. This beam model is extended to a sub-frame in which the restraining effects from the adjoining members are considered. Parametric studies are performed on several sub-frame models and the results are used to show that it is possible to correlate the amount of moment redistribution of semi-continuous beam within the sub-frame using an equivalent stiffness of the connection. Deflection equations are derived for semi-continuous composite beams subjected to various loading and parametric studies on beam vibrations are conducted. The proposed method may be applied using a simple computer or spreadsheet program.

Strain interaction of steel stirrup and EB-FRP web strip in shear-strengthened semi-deep concrete beams

  • Javad Mokari Rahmdel;Erfan Shafei
    • Steel and Composite Structures
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    • v.47 no.3
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    • pp.383-393
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    • 2023
  • Conventional reinforced concrete design codes assume ideal strain evolution in semi-deep beams with externally bonded fiber-reinforced polymer (EB-FRP) web strips. However, there is a strain interaction between internal stirrups and web strips, leading to a notable difference between code-based and experimental shear strengths. Current study provides an experiment-verified detailed numerical framework to assess the potential strain interaction under quasi-static monotonic load. Based on the observations, steel stirrups are effective only for low EB-FRP amounts and the over-strengthening of semi-deep beams prevents the stirrups from yielding, reducing its shear strength contribution. A notable difference is detected between the code-based and the study-based EB-FRP strain values, which is a function of the normalized FRP stress parameter. Semi-analytical relations are proposed to estimate the effective strain and stress of the components considering the potential strain interaction. For the sake of simplification, a linearized correction factor is proposed for the EB-FRP web strip strain, assuming its restraining effect as constant for all steel stirrup amounts.

A Study on Curriculum Improvement of the Korea Army Nursing Academy (국군간호사관학교 교육과정 개선을 위한 기초 연구)

  • 고자경
    • Journal of Korean Academy of Nursing
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    • v.13 no.2
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    • pp.22-43
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    • 1983
  • 1. Need for and Purpose of the Study. There is an increasing demand for curriculum improvement of the Korean Army Nursing Academy (KANA), since it was upgraded into 4-year institution of higher learning from 3-year one. In particular, it is strongly advocated that the KANA needs the outside expertise for its curriculum improvement-namely not only from the internal military view of points but also from the viewpoints of professional educational society, In line with such a necessity for the study, this study was aimed at 1) analyzing the current actual practices of KANA'S curriculum, 2) investigating the desired practices of KANA'S curriculum, and 3) identifying the discrepancy between the actual and desired practices of curriculum. 2. Problems for the Study This study had 4 problems to be answeared as follows: 1) What are the actual curriculum practices of KANA? 2) What are the desired curriculum practices of KANA? 3) How are the extents of perception of actual and desired curriculum different in four groups (student, faculty & administrator, nurse, and medical doctor in militay hospital) ? 4) What are the restraining forces that impede the change from actual to desired curriculum practices? 5) What are the relationships of curriculum component,』 in actual and desired curriculum practices? 3. Methods and Procedures This study was conducted by means of document analysis in addition to literature review and by means of needs assessment questionnaire which was developed by the researcher. The questionnaire included 62 statments with 7 questions for demographic data collection. The needs assessment questionnaire was managed to a total of 243 subjects (100 students, 46 faculty & administrators, 55 nurses, and 42 medical doctors), The collected data were treated using SPSS computer system so as to calculate mean scores, standard deviations, and correlation coefficients. The significance test was made through t-test and one-way ANOVA. The statistical significance level was set at both .05 and .01 level. 4. Major findings The major findings in this study are as follows: 1) The score of desired practices was significantly greater than that of actual practices, representing a strong need for curriculum betterment. 2) There were significant differences in the perceptions of actual practices as well as desired practices among four groups (student, faculty & administrater, nurse, and medical doctor). 3) The most frequently selected restraining forces were army's inherent character, economical limitation, and educational expertise limitations. 4) Such variables as sex, position attachment to the KANA and grade made a statistically significant effect on the perception of desired curriculum practice, while the variables like marrige, position, and military class made it on the perception of actual curriculum practice. 5) The coefficients among the curriculum components were lower in perception of the actual curriculum practices than those in the desired practices. 5. Conclusions The conclusions based on the major findings of this study are as follows: 1) The current curriculum development procedure of the KANA is not consistent with the theoretical frame of systematic development sarategy of curriculum. 2) There are wide conflicts among the groups who are supposed to participate in curriculnm development, concerning the actual and desired practices of KANN'S curriculum. 3) A great deal of need for curriculum improvement for the KANA is clearly felt, and in particular, in the process of teaching and learning. 4) Each component of curriculum is not intergrated into a whole development procedure, being segregated each other. 5) For better curriculum improvement, such restraining forces as financial and professional limitations should be eliminated. 6. Recommendations 1) For Further Research a. There is a need to replicate this study after in-depth statistical analysis of each item of need assessment questionnaire, and with more representative subjects. b. A study should be conducted which. has its focus on the analysis of restraining forces for the change from actual to desired curriculum practices of the KANA. 2) For KANA'S Curriculum Improvement a. There is a need to promote the professional expertise of the participants in curriculum development and the communication among them. b. It is desirable to establish an institution or section of administration, which is soley in charge of curriculum development. c. To better develop KANA's curriculum not only faculty and administrators but also students should be encouraged to participate in development process, while the military medical doctors' participation should be carefully considered.

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A Study of the Effective Weed Control by Herbicides in a Nursery and Forests(I) -Weed Control in a Nursery for Silviculture and Landscape Architecture- (묘포장 및 산지에서 제초제를 이용한 효과적인 잡초방제에 대한 연구(I) -조림.조경용 수묘포장의의 제초관리-)

  • 서병수;김세천;박종민;이창헌
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.1
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    • pp.29-38
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    • 1999
  • Three kinds of soil surface applied herbicides and three kinds of foliage applied herbicides were used to study weed control effect, appropriate concentration, phyto-toxicity against trees and economical efficiency of weed control on trees, Pinus thunbergii, Picea abies, Chamaecyparis obtusa, Quercus accutissima, and Fraxinus rhynchopylla in a nursery. The results were obtained as follows; 1.The control effect of the soil surface applied herbicides showed that the three herbicides; Alachlor, Pendimenthalin and Simazine were alike in their holding effect of weed development, and the sensibility of weed spp. on the herbicides was different. The mean control effect was 58~89%. 2. The weed control effect of the foliage applied herbicides demonstrated that Paraquat dichloride was the best of 84~95% and followed by Glufosnate ammonium and Glyphosate. Especially when the half of its standard amount was treated, the effect of Paraquat dichloride was higher than the other herbicides. 3. Generally, the weed control effect became better as the concentration of the herbcide getting higher. As the concentration of the herbicide got higher, the restraining effect of weed development was continued for a long time in the soil surface applied herbicides, while the weed control effect appeared earlier in the foliage applied herbicides. 4. As the result of the soil surface treatments, 20% of short seedings of Fraxinus rhychopylla treated with twice amount of standard Alachlor died and the rest seeding showed low growth. In the other treatments, there was neither harmful effect of herbicides on the seedings nor growth decrease of them compared to those weeded by men. 5. When treated with foliage applied herbcides, leaves were partially of and discolorated in most treatments. About 0.4~6.2% of Fraxinus thynchopylla, which had short seedings died, and there was no difference in growth with the other treatments. 6. The herbicides showed better economical efficiency over 68% than weed control by men. Especially, Alachlaor of the soil surface applied herbicides showed the highest efficiency(77.6%), while Paraquat dichloride of the foliage applied herbicides was the best(70.3%)..

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Effects of Pinelliae Rhizoma Extract on Sociopsychological Stress (반하(半夏) 추출물이 생쥐의 사회.심리적 스트레스에 미치는 영향)

  • Kim, Su-Youn;Lim, Se-Hyun;Cho, Su-In;Choi, Chang-Won;Kim, Kyeong-Ok
    • Journal of Oriental Neuropsychiatry
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    • v.20 no.3
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    • pp.35-47
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    • 2009
  • Objectives : The effects of Pinelliae Rhizoma extract(PRe) were tested for the anti-stress action. Methods : PRe was fed to ICR male mice($20{\pm}2g$) orally with the dose of 100 mg/kg/day for five days. Mice were exposed to sociopsychological stress by restraining and seeing foot shock stressed mice for one hour for five days. Results : PRe administration had the effect of decreasing serum level of lipid peroxidation. The elevated plus-maze test is designed to detect the effect of anxiolytic drugs, and PRe administration group showed a significant increase of latency time. From Microarray, common features between mind-stimulus related genes and body-stimulus related genes were not so abundant When PRe was administered, there were some changes in distributions of mind-stimulus related genes but the distributions were not recovered to normal status. Conclusions : These results suggest that PRe can effectively rid the sociopsychological stress and stress concrened diseases.

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Energy absorption of the ring stiffened tubes and the application in blast wall design

  • Liao, JinJing;Ma, Guowei
    • Structural Engineering and Mechanics
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    • v.66 no.6
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    • pp.713-727
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    • 2018
  • Thin-walled mental tubes under lateral crushing are desirable and reliable energy absorbers against impact or blast loads. However, the early formations of plastic hinges in the thin cylindrical wall limit the energy absorption performance. This study investigates the energy absorption performance of a simple, light and efficient energy absorber called the ring stiffened tube. Due to the increase of section modulus of tube wall and the restraining effect of the T-stiffener flange, key energy absorption parameters (peak crushing force, energy absorption and specific energy absorption) have been significantly improved against the empty tube. Its potential application in the offshore blast wall design has also been investigated. It is proposed to replace the blast wall endplates at the supports with the energy absorption devices that are made up of the ring stiffened tubes and springs. An analytical model based on beam vibration theory and virtual work theory, in which the boundary conditions at each support are simplified as a translational spring and a rotational spring, has been developed to evaluate the blast mitigation effect of the proposed design scheme. Finite element method has been applied to validate the analytical model. Comparisons of key design criterions such as panel deflection and energy absorption against the traditional design demonstrate the effectiveness of the proposed design in blast alleviation.

A Study on the Buckling Behavior of the Web of Box Girders (상자형 복부판의 좌굴 거동에 관한 연구)

  • Lee, Sang Woo;Kwon, Young Bong
    • Journal of Korean Society of Steel Construction
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    • v.9 no.1 s.30
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    • pp.37-49
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    • 1997
  • The buckling behavior of the web of steel girders are largely dependent on the size and the location of stiffeners and the restraining effect of top and bottom flanges. Elastic and inelastic buckling analyses based or the Spline Finite Strip Method were executed to study the stiffening effect of the longitudinal stiffener on the web of box girders and to find how the top and bottom flanges had effects on the web, where geometric boundary conditions were limited by both hinged, both fixed and the flange sections. The basic assumption for the longitudinal end boundary conditions was that the vertical stiffeners had the rigidity enough to force nil deflection line on the web panel so that the junction line between web and vertical stiffener was assumed to be hinged boundary conditions. The provisions on the longitudinal stiffener of the plate and box girders of the Korean Standard Highway Bridge Specifications(1995) and AASHTO Specifications(1994 LRFD) were compared with the results obtained numerically for the various longitudinal stiffener size of box girders. Simple equations and design curves for the longitudinal stiffener of the web were proposed for the practical use.

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