• Title/Summary/Keyword: Structure Test Model

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Development of a Program for Topophilia Geological Fieldwork Based on Science Field Study Area in Youngdong, Chungcheongbuk-do (충북 영동 지역의 과학학습장을 활용한 토포필리아 야외지질학습 프로그램 개발)

  • Yoon, Ma-Byong;Nam, Kye-Soo;Baek, Je-Eun;Bong, Phil-Hun;Kim, Yu-Young
    • Journal of the Korean Society of Earth Science Education
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    • v.10 no.1
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    • pp.76-89
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    • 2017
  • The purpose of this study is to develop a science field study area using Geumgang(Geum River), fossil origins and various geological resources in Youngdong area of Chungcheongbuk-do as educational resources; and utilize them to develop an education program to cultivate earth science and topophilia. The Youngdong sedimentary basin (Cretaceous period) has a well-developed outcrop along the Geumgang and it is therefore easy to find various geological structures, plant fossils, and dinosaur fossils. Also, it has a distinct sedimentary structure, such as mud cracks, ripple marks and cross-bedding. Science field study area(6 observation sites) were developed based on school curriculum, textbook analysis, and professional earth science education panel discussion to create a convergence education program. The result of validating the developed program showed that all the items were satisfactory ($CVR{\geq}0.88$) in the test categories. The science field study teaching-learning model was applied to actual classes. The evaluation result for class satisfaction was positive, scoring Rickert scale 4.18. The result of observation about the outdoor classroom process in the science field study area revealed that students were able to form a new image of the beautiful scenery of the Geumgang. Also, the students could gain a new understanding, concept and value of various geological objects (sandy beach, stepping-stones, dinosaur footprint fossils, sedimentary formation), which naturally allowed them to form topophilia.

A Study on Performance Characteristics of Horizontal Axis Tidal Turbine Considering Nose Shape, Angle of Inflow and Tower Structure (수평축 조류발전 터빈의 노즈 형상 및 유입각도, 타워 구조물의 영향을 고려한 터빈 성능특성 분석)

  • Heo, Man-Woong;Kim, Dong-Hwan;Yi, Jin-Hak
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.32 no.1
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    • pp.17-25
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    • 2020
  • In this study, three-dimensional fluid flow analyses have been performed in order to investigate the performance characteristics of a horizontal axis tidal turbine (HATT) by solving three-dimensional Reynolds-averaged Navier-Stokes equations utilizing the shear-stress-transport turbulence model. The computational domain for the flow analysis has been composed of hexahedral grids, and the grid dependency test has been carried out so as to determine the optimum grid size. Performance characteristics of the HATT have been investigated in consideration of the effects of hub nose geometry, inflow angle, and the tower. It has been found that the power output can be enhanced along with an increase of the ratio of the length to the diameter of the turbine nose, and the power of HATT has been reduced by approximately 10% when the primary fluid flow had an inflow angle of 15°. The power output of downstream HATT is found to be lower than that of the upstream HATT by about 1%.

Comparision of Tidal Current Patterns at Keum River Estuary before and after Construction of Keum River Bank and Coastal Structures (금강하굿둑과 각종 해안구조물 설치 전, 후의 금강하구역 해수유동 양상 비교)

  • Jang, Chang-Hwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.4
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    • pp.601-610
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    • 2021
  • The tidal current patterns at Keum River Estuary before and after the construction of coastal structures were compared according to the CASES. The depth-integrated and tidal difference treatment applied FLOW2DH numerical model was used for the tidal current predictions. The test conditions consisted of before construction of coastal structures (CASE1), after construction of coastal structures (CASE2), and the addition of watergate operation(CASE1Q and CASE2Q), and present (CASE3). CASE1 showed a stable tidal current pattern, such as a natural estuary. In CASE2, the tidal current velocities and directions of the Keum River Estuary were changed due to the installed coastal structures. In particular, the tidal current velocities of the Gaeya open channel sections (P5~P9) in CASE2 were calculated to be 10~30% larger than that of CASE1. In the case of the Gunsan Inner Harbor (P4), which is closest to the Geum River Estuary, the ebb flow rate was approximately 250~300% faster than that of other CASEs due to the discharge of the watergate operation for 2.7 hours during the ebb of CASE1Q and CASE2Q. This will affect sediment transport, and it is predicted to lead to seabed changes. CASE3 is considered to be entering the stabilization stage according to the simulation of the tidal current velocities and directions of the Keum River Estuary and the surrounding coastal area.

The Effects of Medical Service Quality of the Nursing Hospital in Japan on the Inpatients' Satisfaction and Reuse Intention (일본 요양병원 의료서비스 품질이 입원환자 만족도와 재이용의도에 미치는 영향)

  • Hwang, Sun-Ja
    • The Journal of the Korea Contents Association
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    • v.18 no.11
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    • pp.581-593
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    • 2018
  • The purpose of this study is to examine the effect of the medical service quality of the nursing hospital on the inpatients' satisfaction, reuse intention and to verify the mediating effect of the inpatients' satisfaction. The subjects of this study were 255 male and female inpatients in Hiroshima in Japan. The collected data were used as a model of path coefficients obtained through analysis of covariance structure and hypothesis test. As a result of verification, level of medical team and medical service, reception, facility and fee of the medical service quality of the nursing hospital perceived by the inpatients showed a statistically significant positive correlation with the inpatients' satisfaction. The inpatients' satisfaction showed a statistically significant positive correlation with their reuse intention. The level of medical team and medical service, reception, facility and fee of the medical service quality of the nursing hospital perceived by the inpatients shows a statistically no significant positive correlation with the reuse intention. But, they show a statistically significant positive correlation with the reuse intention with the mediating effect of the inpatients' satisfaction. Finally, the result of this study is to confirm the effect of the medical service quality on the inpatients' satisfaction, reuse intention of the nursing hospital. In this process, it is meaningful to verify the role and function of medical service quality of the nursing hospital.

Analysis of the Difference Between Purchasing Decision Factors and Quality Satisfaction of Community Social Service Investment (지역사회서비스투자사업의 구매결정 요인과 품질만족 차이 분석)

  • Jang, Chun_Ok;Lee, Jung-Eun
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.4
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    • pp.251-256
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    • 2021
  • Currently, in the field of community service, it is expected that the demand will further increase in the future by enabling the form of providing various types of services. However, the local community service investment project is an abstract Although the structure for fair competition was created by introducing a market mechanism derived from the action or principle of psychology that affects human behavior in the field, systematic management and monitoring of the quality of social services is insufficient. The purpose of this study is to find out the relationship between service selection factors and service quality in order to improve the quality of social services in the consumer's way to meet these environmental needs, and to utilize the research results for quality improvement. The research model to be used in this paper measures the five element areas of service satisfaction such as reliability, responsiveness, empathy, certainty, and tangibility, which are used to measure the quality of local community service investment projects. In addition, we are various strategic implications that can induce the quality improvement of local community service investment projects are presented by finding the main factors of the four research hypotheses of this study and utilizing the results.

Development of Clinical Competency Self-Report Scale for Clinical Satisfaction of Occupational Therapy Student (작업치료대학생의 실습만족을 위한 임상수행능력 자기보고식 척도 개발)

  • Lee, Min-Jae;Lee, Sun-Min
    • Journal of Korea Entertainment Industry Association
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    • v.14 no.1
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    • pp.137-147
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    • 2020
  • This study is aimed to develop and validate the clinical competence scale of occupational therapy student. The development of clinical competence scale analyzed the definition of clinical performance and previous studies. preliminary examinations were conducted on 203 occupational therapy departments in 3rd and 4th grade to verify item analysis and job validity. After exploratory factor analysis, eight factors of professional consciousness, 11 items of occupational therapy evaluation factors, 4 items of occupational therapy intervention factors, and 4 items of communication factors were extracted into a total of 27 factors. As a result of verifying the reliability of each factor through the internal consistency coefficient Cronbach's α, it was found to be .87~.94 and the overall reliability was .96. The correlation between the total score and the factors of the clinical competence scale was statistically significant. Through the confirmatory factor analysis, the model fit test of the factor structure for 27 items of 4 factors (χ2=.76, df = .31, CFI = .81, TLI = .80, RMSEA = .79) is considered acceptable. Through this study, The clinical competence scale is a valid and reliable scale that can be useful for objectively assessing.

Negative Effects of City Slogan on the Retrieval of City Memory Unrelated to the Slogan (도시슬로건이 도시기억의 인출에 미치는 부정적 영향 :슬로건과 관련 없는 도시기억을 중심으로)

  • Kim, Dohyung;Hwang, Insuk
    • The Journal of the Korea Contents Association
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    • v.22 no.2
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    • pp.224-236
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    • 2022
  • This study tests the hypotheses that city slogan reduces the retrieval of city memory unrelated to the slogan from the long term memory and that some variables moderate this effect, using the experimental method. The theoretical basis for the hypotheses is from the structure of the long term memory and the principle of memory retrieval discussed in ANM(Associative Network Model). For the test of hypotheses, the study adopted 4 experimental groups (2(slogan relevance: high or low) * 2(slogan concreteness: high or low)) and 1 control group. Each experimental group was exposed to one slogan corresponding to its condition while the control group was not. Then, the recall score was compared among experimental and control groups. One hundred and seventy-four undergraduate students belonging to the college of the authors participated in the study. The sample group was between 18 and 27 years of age, with an average of 22.4 years, and 54 percent comprised males. Results showed that city slogan had a negative effect on the retrieval of city memory unrelated to the slogan in most experimental conditions. This effect was more evident when the slogan had high relevance or high concreteness. But the main effect did not appear when the slogan had low relevance and low concreteness.

Development of Expandable Steel Pipe Piles to Improve Bearing Capacity (지지력 향상을 위한 확장형 강관말뚝에 관한 연구)

  • Kim, Uiseok;Kim, Junghoon;Kim, Jiyoon;Min, Byungchan;Choi, Hangseok
    • Journal of the Korean GEO-environmental Society
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    • v.22 no.12
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    • pp.5-13
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    • 2021
  • Expandable steel pipe piles have been developed to ensure stability and reduce construction costs during underground floor remodeling and extension work. Expandable steel pipe piles are more economical and stable than micropiles. Extensible steel pipe pile is a method of improving the performance of steel pipes by expanding steel pipes underground. In this paper, the changes in buckling strength according to the shape of steel pipes in an extended steel pipe pile were identified, a numerical analysis model was developed to determine the expended part effect of bumps due to steel pipe expansion, and the optimal steel pipe expansion was calculated through material tests. The larger the expansion diameter of the steel pipe and the greater the number of expanded part, the greater the buckling strength. Numerical results showed that the number of expanded part has a greater effect on buckling strength than the expansion rate. When the expansion rate is more than 1.2 times, it can be seen that as the number of expanded part increases, the effect of increasing buckling strength increases significantly. It was also noted that the expanded part effect of the bumps occur significantly when the extension angle is less than 45° and the expansion rate is 1.3 times higher. When the steel pipe is failure, the expanded rate is 20 to 32%, averaging 25.4%. Through the material test, it was analyzed that it is desirable to limit the maximum expansion rate for performing steel pipes to 16%.

RANS simulation of secondary flows in a low pressure turbine cascade: Influence of inlet boundary layer profile

  • Michele, Errante;Andrea, Ferrero;Francesco, Larocca
    • Advances in aircraft and spacecraft science
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    • v.9 no.5
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    • pp.415-431
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    • 2022
  • Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

Structural Safety Assessment of Tie-down for Securing Helicopter (헬리콥터 고정용 안전장치 구조 안전성 평가)

  • Myung Su Yi;Kwang-Chul Seo;Joo Shin Park
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.29 no.4
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    • pp.372-379
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    • 2023
  • International oil prices are expected to increase from $85 a barrel this year to up to $100 a barrel in the second half of the year; this is likely to increase orders for offshore plants in the global market. One main characteristic of offshore plants is that a large helideck is located on the top side, and aluminum alloys are used as the basic material of the structure for weight reduction and corrosion resistance. Shipowners are increasing the size of helicopters to quickly evacuate lives in the event of an emergency, and the safety use load of devices that can stably secure helicopters to the deck is also required to increase. Owing to the nature of the aluminum material, the structural strength caused by welding is greatly reduced; therefore, the fixing device must be designed by embedding it in the deck and fixing it with bolts. In this study, a model applying aluminum alloy 6082-T6 was developed to develop a helicopter fastening device that can be used for large helidecks (diameter = 28 m). The developed item was verified through nonlinear structural strength calculation to satisfy the load used for the actual fastening condition. The load condition with a 45° showed a lower ultimate strength than the 90° case owing to local plastic collapse. The nonlinear structural collapse behavior showed a result similar to that of the experimental test. The main contents derived from this study are considered to be reference materials when evaluating the structural strength of similar aluminum equipment.