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Seismic performance of precast assembled bridge piers with hybrid connection

  • Shuang, Zou;Heisha, Wenliuhan;Yanhui, Liu;Zhipeng, Zhai;Chongbin, Zhang
    • Structural Engineering and Mechanics
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    • v.85 no.3
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    • pp.407-417
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    • 2023
  • Precast assembled bridge piers with hybrid connection (PASP) use both tendons and socket connections. To study the seismic performance of PASP, a full-scale in-situ test was performed based on an actual bridge project. The elastic-plastic fiber model of PASP was established using finite element software, and numerical analyses were performed to study the influence of prestress degree and socket depth on the PASP seismic performance. The results show that the typical failure mode of PASP under horizontal load is bending failure dominated by concrete cracking at the joint between the column and cushion cap. The cracking of the pier concrete and opening of joints depend on the prestress degree and socket depth. The prestressing tendons and socket connection can provide enough ductility, strength, restoration capability, and bending strength under small horizontal displacements. Although the bearing capacity and post yield stiffness of the pier can be improved to some extent by increasing the prestressing force, ductility is reduced, and residual deformation is increased. Overall, there are reasonable minimum socket depths to ensure the reliability of the socket connection.

Open-heart surgery using Del-Nido cardioplegia in two dogs: partial atrioventricular septal defect and mitral repair

  • Won-Jong Lee ;Chang-Hwan Moon;Wonkyoung Yoon;Mihyung Kim ;Woo-Jin Kim ;Kyung-Min Kim ;Haebeom Lee;Seong-Mok Jeong ;Jae Hyeon Yu ;Dae-Hyun Kim
    • Journal of Veterinary Science
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    • v.24 no.3
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    • pp.47.1-47.7
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    • 2023
  • Del-Nido cardioplegia (DNc) is a single-dose cardioplegia that is widely used in human medicine because of its long duration. In this report, we describe two cases of open-heart surgery with cardiopulmonary bypass (CPB) using DNc. One dog was diagnosed with partial atrioventricular septal defect, and the other dog was diagnosed with myxomatous mitral valve disease stage D. Both dogs were treated with open-heart surgery with DNc to induce temporary cardiac arrest. No complications from DNc were observed, and the patients were discharged. Veterinary heart surgeons should consider DNc as an option for temporary cardiac arrest during open-heart surgery with CPB.

Study on the Fractures Types of PHC Pile by Impact Load of Follower (보조말뚝의 충격하중에 의한 PHC말뚝의 파손유형 고찰)

  • Seo, Dong-Nam;Choi, Sang-Ho;Kim, Jin-Sik;Kim, Min-Kab;Lee, Dong-Hyeon;Cho, Seong-Jun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.144-145
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    • 2021
  • This study analyzed the cases of cracks in piles due to the use of followers under construction conditions where water exists inside the piles, and confirmed whether the piles were cracked through a field test simulating the construction conditions in which water pressure inside the piles was generated by a hammer. According to the construction case, under the construction condition where the pile length is 20% to 30% shorter than the drilled length, about 80% cracks occur, so there is a high possibility of cracking due to water inside the pile. A field test was conducted to confirm the type of pile failure due to hammer under the construction condition in which water exists inside the pile. The pile head was not destroyed by the compressive load, and one or more longitudinal cracks occurred along the PC steel wire. The closed end pile generates water pressure by hammer. the follower and cushion(compression plywood) must be drilled at least 0.4D. It is expected that improved quality control will be possible as the water pressure inside the pile is reduced.

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A Comparison of Determinants of International Remittance in Developed and Developing Countries (해외 송금 결정 요인: 개도국과 선진국의 비교 분석)

  • Seung-Hwan Yoon
    • Korea Trade Review
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    • v.47 no.2
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    • pp.89-101
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    • 2022
  • International remittances play a crucial role in the economic management of each country, especially in developing countries. Its functions are diverse, including procurement of foreign currency, serving as a cushion for the balance of payments and foreign exchange reserves by reducing the adverse external shocks, driving economic growth, easing the gap between the rich and the poor, and maintaining macroeconomic stability. However, previous studies on remittances have mainly focused on macro-and micro-economic aspects to analyze the determinants. Therefore, this study attempts to identify the determinants of remittances in 122 countries over the past 25 years from macroeconomic and educational aspects as well as institutional qualities. In addition, given the fact that almost all of the world's top 10 recipient countries in terms of GDP and total remittance size are developing countries, developed and developing countries are separated and analyzed for comparison, assuming that there may be a difference between the two groups. Results show that the coefficients of developed and developing countries are different in four areas: Control of Corruption (CC), Rule of Law (RL), Voice and Accountability (VA), and Regulatory Quality (RQ) among the six institutional variables of interest in this study. These results implicate that even the same institutions and policies should be applied and implemented differently depending on the circumstances of each country. In addition, as suggested by the World Bank, policymakers in all countries should double their policy efforts to lower the costs of remittance and improve access to the financial system for immigrants or dispatched workers to ensure a steady inflow of remittances.

Comparison between US NCAP and IIHS Side Impact Tests and a Study of Noise Factors of Side Impact Tests (US NCAP 및 IIHS 측면 충돌 시험법간 특성 비교 및 시험 시 오차 인자에 의한 영향 검토)

  • Junsuk Bae;Ho Kim;Young Myoung So
    • Journal of Auto-vehicle Safety Association
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    • v.16 no.1
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    • pp.12-20
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    • 2024
  • Side impact with MDB (moving deformable barrier) is common in side crash test protocols around the globe, most of which are quite similar to that of US NCAP side impact protocol but IIHS side impact protocol is considered to be the most harsh one due to the MDB's weight and impact speed. In this study US NCAP side impact and IIHS side impact test conditions are compared with respect to delta-V (impulse of the test vehicle), roll speed, and yaw speed as well as survival space (the smallest distance between the front driver seat cushion center to B pillar after the test). Error factors (friction between tire and ground, tolerance of vertical and longitudinal position of the MDB with respect to the test vehicle), which are resident in the test protocol is studied with respect to the global vehicle behavior (delta-V, roll, yaw) as well as survival space.

Household food insecurity and coping strategies in a poor rural community in Malaysia

  • Shariff, Zalilah Mohd.;Khor, Geok Lin
    • Nutrition Research and Practice
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    • v.2 no.1
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    • pp.26-34
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    • 2008
  • This cross-sectional study assessed household food insecurity among low-income rural communities and examined its association with demographic and socioeconomic factors as well as coping strategies to minimize food insecurity. Demographic, socioeconomic, expenditure and coping strategy data were collected from 200 women of poor households in a rural community in Malaysia. Households were categorized as either food secure (n=84) or food insecure (n=116) using the Radimer/Cornell Hunger and Food Insecurity instrument. T-test, Chi-square and logistic regression were utilized for comparison of factors between food secure and food insecure households and determination of factors associated with household food insecurity, respectively. More of the food insecure households were living below the poverty line, had a larger household size, more children and school-going children and mothers as housewives. As food insecure households had more school-going children, reducing expenditures on the children's education is an important strategy to reduce household expenditures. Borrowing money to buy foods, receiving foods from family members, relatives and neighbors and reducing the number of meals seemed to cushion the food insecure households from experiencing food insufficiency. Most of the food insecure households adopted the strategy on cooking whatever is available at home for their meals. The logistic regression model indicates that food insecure households were likely to have more children (OR=1.71; p<0.05) and non-working mothers (OR=6.15; p<0.05), did not own any land (OR=3.18; p<0.05) and adopted the strategy of food preparation based on whatever is available at their homes (OR=4.33; p<0.05). However, mothers who reported to borrow money to purchase food (OR=O.84; p<0.05) and households with higher incomes of fathers (OR=O.99; p<0.05) were more likely to be food secure. Understanding the factors that contribute to household food insecurity is imperative so that effective strategies could be developed and implemented.

Evaluation of the Functional and Non-functional Seat Sponge Effect in Sitting Chairs

  • Min, Seung Nam;Park, Se Jin;Subramaniyam, Murali;Lee, Heeran
    • Journal of the Ergonomics Society of Korea
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    • v.33 no.4
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    • pp.255-265
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    • 2014
  • Objective: The purpose of this study was to evaluate comfort levels of functional and non-functional chairs using subjective comfort rating, interface pressure measurement, muscle activity measurement, and skin temperature measurement. Background: Chairs are used for a prolonged period of time for sitting in many places such as the office, at university, at school, in industry, and so on. Almost all people use chairs in their everyday life. The functional properties of the chair are associated with comfort. Method: The subjective evaluation contains questions regarding chair comfort which can be rated with five point scale. The body-seat interface pressure was measured using a pressure mat system. The symmetry of sitting was measured using electromyography. The change in body part (thigh and buttock) temperature before and after sitting on a chair was measured with an infrared camera. Results: Participants rated significantly (p < 0.05) higher comfort scores for the functional chair in relation to the buttock and thigh region. Also, the participants felt a better cushion effect in the functional chair. When using the functional chair, lower interface pressure, better thermal comfort, and better symmetry of erector spinae muscle activity were observed. Conclusion: Overall, interface pressure measurement, muscle activity measurement, thermal imaging and subjective comfort score results showed that the functional chair was more comfortable than the non-functional chair. Application: The adopted methodologies could be used to measure the seating comfort of train seats.

Biomechanical Evaluation of the Neck and Shoulder When Using Pillows with Various Inner Materials

  • Kim, Jung-Yong;Park, Ji-Soo;Park, Dae-Eun
    • Journal of the Ergonomics Society of Korea
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    • v.30 no.2
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    • pp.339-347
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    • 2011
  • Objective: The purpose of this study was to evaluate of various material of pillows by using biomechanical variables such as the cervical stability, head pressure distribution, and muscle activity. Method: Eight subjects participated in the experiment. Three different materials such as polyester sponge, memory foam and the buckwheat shell used for Korean traditional pillow were tested. Electro-goniometer, six channels of electromyography(EMG), ten channels of the head pressure sensors were used to measure the biomechanical responses. Surface electrodes were attached to the right/left semispinals capitis(RSC, LSC), the right/left sternocleidomastoid(RSM, LSM), the right/left upper trapezius(RUT, LUT). The cervical stability was evaluated by the angle deviated from the standing neck position. The head pressure distribution was evaluated by the pressure per unit area recorded on the sensors and the intensity of peak pressure. Electromyography(EMG) data were analyzed by using root mean square(RMS) and mean power frequency(MPF). Results: The buckwheat shell material showed a higher stability in the cervical spine then the other pillows during spine position. In terms of head pressure distribution, the memory form indicated the lowest pressure at supine position, buckwheat shell material indicated the lowest pressure during lying down to side, and polyester cushion recorded the highest pressure at all postures. Conclusion: The buckwheat shell material has a biomechanical advantage to maintain a healthy neck angle and reduce the pressure on the head, which means the buckwheat shell is a potential material for ergonomic pillow design. The pillow with memory form showed second best biomechanical performance in this study. Application: The shape of the buckwheat shell pillow and the characteristics of materials can be used to design the pillow preventing neck pain and cervical disk problems.

The reliability of dual rehabilitative ultrasound imaging measurements for muscle co-activation

  • Hahn, Joohee;Ha, Hyun-Geun;Lee, Hwang-Jae;Lim, Seungyeop;Lee, Wan-hee
    • Physical Therapy Rehabilitation Science
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    • v.6 no.3
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    • pp.152-157
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    • 2017
  • Objective: The aim of this study was to determine the intra-rater and inter-rater reliability of the dual rehabilitative ultrasound imaging (D-RUSI) when simultaneously measuring muscle thickness changes at rest and during co-contraction of the biceps brachii (BB) and triceps brachii (TB). Design: Cross-sectional study. Methods: This study included 36 healthy participants (23 men, 13 women). The participants sat on a chair in a comfortable position with a cushion placed under their elbow to maintain a 90-degree elbow flexion angle. The muscle thickness of the biceps brachii and triceps brachii was measured twice using the D-RUSI by two examiners during resting and co-contraction states. One week later, the same procedure was performed once again. Results: The intra-class correlation coefficients (ICCs) for intra-rater reliability ranged from 0.887 to 0.989 and the confidence interval was within an acceptable range of 0.778 to 0.994. The standard error of measurement (SEM) values ranged from 0.303 to 0.866 and the minimal detectable change (MDC) values ranged from 0.84 to 2.40. The ICCs for inter-rater reliability ranged from 0.758 to 0.925. The SEM values ranged from 0.702 to 1.486 and the MDC values ranged from 1.95 to 4.12. Conclusions: The use of the D-RUSI of the BB muscle had a very good intra-rater reliability and very good inter-rater reliability at the resting state, and a, good inter-rater reliability at the co-activation state. ICC values showed very good intra-reliability and inter-reliability for the TB muscle. the D-RUSI is a useful tool for simultaneously measuring the thickness of two muscles when the BB is an agonist and the TB is an antagonist during co-activation of the upper arm.

Relationship of Test Methods of Impact Absorbing Effect of Floors from a viewpoint of Safety in Accidental Collisions (인체충돌시 바닥의 안전성에 관한 시험방법간 연관성 분석)

  • Kim, Sang-Heon;Ji, Suk-Won;Yoon, Jung-Sik;Choi, Soo-Kyug;Seo, Chee-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.11 no.1
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    • pp.29-34
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    • 2011
  • Since the study of building performance design was first undertaken by Building Research Station in 1930s, the results of such study has been reported from many parts of the world, building construction codes and standards have been revised based on performance in advanced nations as well in Korea, and various performance certification systems are in operation. The purpose of this study is to build a database of performance certification systems to investigate the co-relationship of various test methods related to the same test items. As test methods for case study, we selected test methods involving collision of the human body. Through analysis of Critical fall height test of EN 1177 and Head Model test of JIS A 6519 about 8 species of floor test-bodies, it was found that there are limits of application in terms of the depth and strength of cushion. Furthermore, although the measured physical parameters are the same, when the co-relationship between test methods is uncertain, the various physical parameters may not be compatible with the results.