• 한국지진공학회논문집
• /
• 제18권1호
• /
• pp.1-8
• /
• 2014

The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction. The proposed reinforcement details have economic feasibility and rationality and make construction periods shorter. A model of hollow reinforced concrete bridge columns was tested under a constant axial load and a quasi-static cyclically reversed horizontal load. As a result, proposed reinforcement details for material quantity reduction were equal to existing reinforcement details in terms of required performance. The companion paper presents the experimental and analytical study for the performance assessment of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction.

• Journal of Welding and Joining
• /
• 제13권1호
• /
• pp.138-144
• /
• 1995

Recently, as the industrial structure tends to become large, the thickness of structural plate becomes thicker. Therefore, the thicker the plate of welded structure is, the larger the shape of welded joint. The effect of large heat input makes large heat affected zone(HAZ). These bring to complict welding residual stress and to weaken material, which may cause extremely harm to the safety of structures. Nevertheless, welding is design is regulated by the KS, JIS or standard in the resister of shipping such as KR, ABS or LR. However, these rules are based on rather experimental than theoretical. In this study, the computer program of heat conduction, considering un-steady state and quasi-steady state, is developed for optimizing(minimizing) a shape of welded joint. The characteristics of heat on the welded joints with various shapes are clarified by the results of the analyses.

• 한국음향학회지
• /
• 제20권4호
• /
• pp.54-61
• /
• 2001

자왜 재료는 비선형 자기-탄성 특성을 갖는다고 알려져 있다. 그러나 비선형 특성을 표현하는 자왜 재료의 비선형 구조 방정식을 4차 텐서를 이용하여 유도하였고, 준선형 (quasi-linear)화시킨 압자구조방정식을 이용하여 자왜 재료 내의 파동 방정식을 유도하였다. 유도된 식을 바탕으로 자왜 재료에서 평면파가 자계 방향을 따라 전파될 때의 탄성파 속도를 구하였다. 나아가 자왜 재료 중에서 가장 널리 사용되고 있는 Terfenol-D의 탄성파 속도를 측정하여 본 연구에서 유도한 자왜 재료 비선형 구조 방정식의 타당성을 검증하였다.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제9권2호
• /
• pp.44-50
• /
• 2001

The Sirocco fan performance and its three-dimensional flow characteristics are numerically prediction by STAR-CD. Turbulent flow computations are performed using approximately 500,000 mesh points, and the performance results of tow computational methods, transient and quasi-static flow analyses are compared with experimental data. In the present study, our attention is focused on the three-dimensional flow characteristics of the Sirocco fan blades and the secondary flow structure in the scroll. For a design optimization study, the scroll shape is titled by $10^\circ$ to modify the secondary flow structure, which yields some improvement of the fan performance.

• Nuclear Engineering and Technology
• /
• 제51권7호
• /
• pp.1822-1827
• /
• 2019

Mechanical responses and failure behaviors of advanced C/C composite tube are very important for structural component design in nuclear reactor. In this study, an experimental investigation was conducted to study mechanical properties of C/C composite tube. Quasi-static compression loading was applied to a type of advanced composite tube to determine the response of the quasi-static load displacement curve during progressive damage. Acoustic emissions (AE) signals were captured and analyzed to characterize the crack formation and crack development. In addition, the crack propagation of the specimens was monitored by imaging technique and failure mode of the specimen was analyzed. FEM is appled to simulate the stress distribution. Results show that advanced C/C composite tube exhibits considerable energy absorption capability and stability in load-carrying capacity.

• 여성건강간호학회지
• /
• 제12권2호
• /
• pp.168-176
• /
• 2006

Purpose: This study was to investigate the effects of aromatherapy massage on pain, physical function, sleep disturbance and depression in elderly women with osteoarthritis. Method: The study design was a quasi-experiment design with a non-equivalent control group pre and post-test. The study pool included elderly female patients older than 65years old suffering from osteoarthritis. Results: Pain in the experimental group after the aromatherapy massage was significantly decreased than that in the control group. The physical disability in the experimental group after the aromatherapy massage was significantly decreased than that in the control group. The sleep disturbance in the experimental group after the aromatherapy massage was significantly decreased than that in the control group. The depression in the experimental group after the aromatherapy massage was significantly decreased than that in the control group. Conclusion: Aromatherapy may be adopted as an effective nursing intervention for osteoarthritis.

• 종양간호연구
• /
• 제7권1호
• /
• pp.47-55
• /
• 2007

Purpose: The purpose of this study was to examine the effects of foot massage as a nursing intervention on the anxiety and pain of the mastectomy patients. Method: This research was quasi-experimental study of a total of 28 patients with 14 in the experimental group and 14 in the control group. For the experimental group, foot massage for 30 minutes was given by a foot-massage specialist. Anxiety and pain were measure once before the foot massage and five times after the massage. The collected data were analyzed by repeated ANOVA and t-test using the SPSS 12.0 program. Result: There was a statistically significant decrease in anxiety and pain in the experimental group compared to the control group over 5 different times. Conclusion: The foot massage was effective on anxiety and pain in mastectomy patients in this study. Therefore, foot massage would be usefully utilized as a nursing intervention for mastectomy patients.

• International Journal of Computer Science & Network Security
• /
• 제22권4호
• /
• pp.229-236
• /
• 2022

This study investigates the impact of flipped classroom strategy in developing students' achievement and acquisition of life skills. The study employed a quasi-experimental design where students were divided into two groups: an experimental (N=22) and a control (N=22). The randomly selected and assigned sample consisted of sixth-year elementary school students studying English as a basic course. The findings revealed statistically significant differences between the two group's means in both achievement and life skills tests in favor of the experimental group. Students of the experimental group who studied using the flipped classroom strategy outperformed the control group who studied in the standard way in achieving the English language and in the life situations test, where the effect size of the use of the strategy was large in both dependent variables. The study is concluded with some recommendations to facilitate the use of flipped classroom strategy for EFL teachers. This can be achieved by training teachers on using the strategy and providing technological resources at schools to implement the strategy efficiently.

• International Journal of Computer Science & Network Security
• /
• 제22권8호
• /
• pp.145-152
• /
• 2022

The current study investigates the effects of an interactive learning environment on EFL students' vocabulary acquisition and reading comprehension skills. The study utilized a quasi-experimental design. The sample consisted of 41 students enrolled in the English program at Umm Al-Qura University studying Reading in EFL course in Summer 2018/2019. The sample was randomly divided into two groups: A control group consisting of 21 students and an experimental group of 20 students. The results revealed statistically significant differences at (α≤ 0.01) between the mean scores of the experimental group and the control group in the posttest of the vocabulary test and the reading comprehension test favoring the experimental group. Finally, the study concluded with a call for more studies on modern technologies in teaching EFL skills in the Saudi context.

• 한국해안·해양공학회논문집
• /
• 제30권1호
• /
• pp.1-9
• /
• 2018

본 연구에서는 투과성 판을 통과하면서 발생하는 에너지 손실효과를 나타내는 비선형 항력 항을 등가 선형화기법으로 선형화시킨 준선형 모델을 제안하였다. 이 모델을 경계요소법(Boundary Element Method)으로 풀어 2차원 조파수조의 투과성 소파장치를 개발에 활용하였다. 투과성 판에서의 항력계수는 수리 모형실험 결과와 비교를 통해 새롭게 구하였다. 공극률 0.1, 잠긴 깊이 d/h = 0.1, 경사각도 $10^{\circ}{\leq}{\theta}{\leq}20^{\circ}$를 갖는 투과성 소파장치가 전반적으로 우수한 소파성능을 보였다. 개발된 준선형 수치모델은 앞으로 다양한 형태의 투과성 소파장치의 최적 설계에 활용될 것이다.