• Title/Summary/Keyword: Behavior test

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Behavior of High-Speed Rail Roadbed Reinforced by Geogrid under Cyclic Loading (지오그리드로 보강한 고속철도 노반의 거동 특성)

  • 신은철;김두환
    • Journal of the Korean Society for Railway
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    • v.3 no.2
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    • pp.84-91
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    • 2000
  • The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. With the test results, the bearing capacity ratio, elastic rebound ratio, subgrade modulus and the strain of geogrids under loading were investigated. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to estimate the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

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Analysis of Time-dependent Axial Force of Shores using the Winkler Model (Winkler모델을 이용한 동바리의 시간의존적 축력 해석법)

  • 우창훈;김선영;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2002.04a
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    • pp.27-34
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    • 2002
  • In the case of reinforced concrete structures, the knowledge of load transfer in the long-term behavior analysis considering construction sequence is very important. Even though long-term behavior of concrete structures has been widely studied, the studies on the time-dependent axial force variation of shore have been scarce to date. In order to investigate the shore behaviors under actual construction conditions, a three-story test frame was constructed on a construction site. The entire construction schedule for the test frame was made to follow the schedule of an actual three-story frame. To analyze the data collected from the test frame, an analysis method based on the Winkler foundation model was developed. This analysis method accurately Predicts the time-dependent behavior of shore. The analysis results coincide well with those obtained by the Midas GENw program

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The Development and the Effects of Injury Prevention Program of Infants and Toddlers for Teachers in Childcare Centers (보육교사를 위한 영아 상해예방 프로그램 개발과 효과)

  • Kim, Hye-Gum
    • Journal of Families and Better Life
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    • v.29 no.3
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    • pp.1-12
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    • 2011
  • The study aimed to improve the injury belief, injury prevention behavior, and safety fulfillment confidence of teachers of infants and toddlers in childcare centers. The study subjects were 376 teachers who were assigned to either the intervention group or the control group. The intervention group participated in an Injury Prevention Program for infants and toddlers for 100 minutes once a week for a total of 5 sessions, while the control group did not. The collected data were statistically analyzed through the independent t-test and paired t-test. The injury belief and injury prevention behavior test scores of the teachers in the intervention group were significantly increased compared to those in the control group after the completion of the five-week program.

Numerical simulation of complex hexagonal structures to predict drop behavior under submerged and fluid flow conditions

  • Yoon, K.H.;Lee, H.S.;Oh, S.H.;Choi, C.R.
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.31-44
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    • 2019
  • This study simulated a control rod assembly (CRA), which is a part of reactor shutdown systems, in immersed and fluid flow conditions. The CRA was inserted into the reactor core within a predetermined time limit under normal and abnormal operating conditions, and the CRA (which consists of complex geometric shapes) drop behavior is numerically modeled for simulation. A full-scale prototype CRA drop test is established under room temperature and water-fluid conditions for verification and validation. This paper describes the details of the numerical modeling and analysis results of the several conditions. Results from the developed numerical simulation code are compared with the test results to verify the numerical model and developed computer code. The developed code is in very good agreement with the test results and this numerical analysis model and method may replace the experimental and CFD method to predict the drop behavior of CRA.

Development of Evaluation Technique of High Temperature Creep Characteristics by Small Punch-Creep Test Method (I) - Boiler Superheater Tube - (SP-Creep 시험에 의한 고온 크리프 특성 평가 기술 개발(I) - 보일러 과열기 튜브 -)

  • Baek, Seung-Se;Na, Seong-Hun;Na, Ui-Gyun;Yu, Hyo-Seon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.12
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    • pp.1995-2001
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    • 2001
  • In this study, a small punch creep(SP-Creep) test using miniaturized specimen(10${\times}$10${\times}$0.5mm) is described to develop the new creep test method for high temperature structural materials. The SP-Creep test is applied to 2.25Cr-lMo(STBA24) steel which is widely used as boiler tube material. The test temperatures applied for the creep deformation of miniaturized specimens are between 550∼600$^{\circ}C$. The SP-Creep curves depend definitely on applied load and creep temperature, and show the three stages of creep behavior like in conventional uniaxial tensile creep curves. The load exponent of miniaturized specimen decreases with increasing test temperature, and its behavior is similar to stress exponent behavior of uniaxial creep test. The creep activation energy obtained from the relationship between SP-Creep rate and test temperature decreases as the applied load increases. A predicting equation or SP-Creep rate for 2.25Cr-lMo steel is suggested. and a good agreement between experimental and calculated data has been found.

Behavior characteristics of Light-Weight Pavement Using Centrifuge Test (원심모형실험을 이용한 경량포장체의 거동특성)

  • Kim, Seong-Kyum;Lee, Kwan-Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.10
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    • pp.5176-5183
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    • 2013
  • In general, Korean Lightweight Concrete used Heat insulating material for building and filler for civil construction, backfill material for tunnel, office floor fillers, lightweight blocks and so on. These expand the range of use ALC(autoclaved lightweight concrete) on the soft-ground at regular intervals during road construction by installing piles used as substrates for the process is under study. In this study, behavior characteristics on the soft-ground of pavement analysis was used to test the geo-Centrifuge. Prototype pavement reduced to 1/30 slab form of the composition as kaolinite model tests were conducted in the soft ground. Pile Arrangement (having 36 component pile with an array of $3{\times}12$) was used to group of piles. Tests of gravity 30 level the centrifugal force acting Light-weight pavement models. Based on the Prototype pavement of the behavior characteristics of pavement behavior characteristics were estimated. FMA analysis of the 10 times as big 39.4kg (actual load 35 ton) of the lateral load is applied to the case 7.8mm (actual behavior 23.4mm) behavior was fine.

The Effect of Education Program on Primiparas로 Knowledge, Confidence and Accuracy of Behavior in Newborn Care (신생아 돌보기 교육 프로그램이 초산모의 신생아 돌보기 지식, 자신감, 행동 정확도에 미치는 효과)

  • 서영미
    • Journal of Korean Academy of Nursing
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    • v.28 no.4
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    • pp.1060-1074
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    • 1998
  • This study was to find whether the educational program contributed to the increase of knowledge, confidence, and accuracy of behavior in newborn care of the primiparas. The educational program consistes of individual lectures, demostrations, discussion, and practice of newborn care. Also two telephone counseling with the subjects after they are discharged from hospital. This study is a quasi-experimental design using non-equivalent control group pretest-posttest design. Data collection was done from July 21 to Oct 4 in 1997. The subjects were selected from 2 general hospitals and 1 university hosipital in C city, Subjects were 44 primiparas(control group 22, experimental group 22). they were tested on knowledge, confidence, and accuracy of behavior in newborn care. A pretest was done 2-3 days after vaginal delivary(5-6 days after c-sec delivary). A posttest was done 21-28 day(vaginal delivary, c-sec delivary) after delivary. The instruments used for this study were knowledge scale about newbon care developed by the reserarcher, Pharis' confidence scale modified by the researcher and accuracy of behavior scale developed by the reserarcher. Primiparas' knowledge and confidence was tested by questionnaire and Primiparas' accuracy of behavior was tested by structured observational method. Analysis of data was done by using of χ²- test, t -test, paired t -test. The results of this study are summarized as follows : 1) Knowledge of the experimental group was significant higher than the control group(t=-4.94, P=.000). 2) Confidence of the experimental group was significant higher than the control group(t=-.262, P=.012). 3) Accuracy of behavior of the experimental group was significant higher than the control group (t=-.969, P=.000). In conclusion, the newborn care education along with intensive telephon counseling shows a significant promotion of newbon care in primiparas. Thus this program can be recommended as an intervention model for the newborn and primiparas.

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Influence of Different Perspectives about Well-being Trend LOHAS on the Menu Selecting Behavior of Diners-out (웰빙 트렌드 로하스(LOHAS)에 관한 외식 소비자의 인식 차이가 메뉴 선택 행동에 미치는 영향)

  • Cho, Woo-Je
    • Culinary science and hospitality research
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    • v.15 no.3
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    • pp.307-323
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    • 2009
  • This study aims to redefine people's attitudes about well-being trend LOHAS(Lifestyles Of Health And Sustainability) by a systematic research on diners' perspectives about LOHAS and menu-selecting behavior since well-being trend has been a main interest of the media and the food service industry. Also, this study has focused on understanding customers' menu-selecting behavior through a customer interest survey and on customers' interests and verifying factors for healthy food inclination and satisfaction level to give basic information and marketing suggestions for healthful menu. SPSS 12.0 was used for the data analysis, and $x^$-test was carried to make clear the different perspectives about well-being trend LOHAS according to the general characteristics of those polled. Factor analysis was done to menu-selecting behavior. Differences between sampling menu-selecting factors and general characteristics(t-test & ANOVA) were inspected and multiple regression analysis between health inclination and satisfaction level was also conducted. According to the survey, customers' well-being menu selecting behavior showed highly in married women, relatively older people, those with higher general income and higher education. Regression analysis showed that menu-selecting behavior influenced customers' inclination toward health and satisfaction level. Therefore, the food service industry should target those groups and improve its promotional communication strategy with proper menu development and an improved concept.

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Attitude toward Plastic Surgery and Clothing Behavior according to Females' Appearance Concerns (여성의 외모관심도에 따른 성형태도와 의복행동)

  • Park, Eunhee;Cho, Hyonju
    • Journal of Fashion Business
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    • v.18 no.2
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    • pp.132-147
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    • 2014
  • The purpose of this study is to classify the appearance concern into groups and analyze the differences of the attitude toward plastic surgery and clothing behavior by groups. Questionnaires are administered to 206 female adults in their 20's-50's living in Deagu and Kyungbook areas from $10^{th}$ July to $19^{th}$ July, 2013. Frequency, factor analysis, reliability analysis, correlation analysis, cluster analysis, ANOVA, Duncan-test and ${\chi}^2$-test were used for data analysis. The appearance concern is categorized as follows: appearance harmony focus and body focus. The attitude toward plastic surgery was found as risk tolerance, image improvement/surgery desire and keeping the secret of surgery. Clothing behaviors are found as individuality focus, other focus, convenience and luxury ostentation. The appearance concern shows a significant correlation with the sub-variable attitude toward plastic surgery and clothing behavior. One test in the groups is determined by demographic variables like occupancy and monthly income. Appearance concerns are classified into three groups as follows: appearance concern group, low appearance concern group and body concern group. The groups show a significant difference in the attitude toward plastic surgery and clothing behavior. This difference indicates that the 20's show a high body focus on their appearance concern, an attitude of image improvement/surgery desire toward plastic surgery and another individuality focus on clothing behavior while 50's care more about convenience in their clothing behavior.

Workability and compressive behavior of PVA-ECC with CNTs

  • Lee, Dongmin;Lee, Seong-Cheol;Yoo, Sung-Won
    • Geomechanics and Engineering
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    • v.29 no.3
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    • pp.311-320
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    • 2022
  • TBM concrete segment requires a higher level of material properties compared to general concrete structures due to difficulties in maintenance and uncertainty in ground conditions. In this regard, recently, as one of the methods to achieve enhancement effect on concrete strength, many researchers have been focusing on adding CNTs to concrete mixture. However, even CNTs do not compensate the weakness that concrete exhibits brittle behavior after cracking. Separately, over the past few decades, a number of studies have been conducted on fiber reinforced concrete which exhibits ductile behavior due to fibers bridging cracks. However, only limited studies have been conducted to employ the advantages of the both materials together. In this study, an experimental program has been conducted to investigate the effect of CNTs on the workability and the compressive behavior of PVA-ECC which exhibits ductile tensile behavior with well-distributed cracks even without a conventional rebar. In addition to the compression test, SEM analysis has been also conducted for detailed investigation in the microstructure. The variable was the CNTs mix ratio, which were set to 0.00, 0.25, and 0.50 wt.% to the binding materials. It was observed though the test results that as the CNTs mix ratio increased, the workability considerably decreased with the reduced slump and slump flow. From the compression test results, it was also investigated that the compressive behavior was improved since the compressive strength, the strain corresponding to the compressive strength, and the modulus of elasticity increased with an increase of CNTs mix ratio. The contents of this paper will be useful for relevant research areas such as fiber reinforced concrete with CNTs which might be applied for high performance TMB concrete segments.