• Structural Engineering and Mechanics
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• v.71 no.6
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• pp.683-697
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• 2019

The reinforced concrete (RC) structures usually suffer large residual displacements under strong motions. The large residual displacements may substantially reduce the anti-seismic capacity of structures during the aftershock and increase the difficulty and cost of structural repair after an earthquake. To reduce the adverse residual displacement, several self-centering energy dissipation braces (SCEBs) have been proposed to be installed to the RC structures. To investigate the seismic responses of the RC structures with SCEBs under the earthquake excitation, an extended Bouc-Wen model with degradation and self-centering effects is developed in this study. The extended model realized by MATLAB/Simulink program is able to capture the hysteretic characteristics of the RC structures with SCEBs, such as the energy dissipation and the degradation, especially the self-centering effect. The predicted hysteretic behavior of the RC structures with SCEBs based on the extended model, which used the unscented Kalman filter (UKF) for parameter identification, is compared with the experimental results. Comparison results show that the predicted hysteretic curves can be in good agreement with the experimental results. The nonlinear dynamic analyses using the extended model are then carried out to explore the seismic performance of the RC structures with SCEBs. The analysis results demonstrate that the SCEB can effectively reduce the residual displacements of the RC structures, but slightly increase the acceleration.

• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.531-536
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• 1999

Experiments on micro-leak of water were carried out with the water injecting simulator in liquid sodium atmosphere. The leak path was plugged by the sodium-water reaction products in the 2.25Cr-1Mo steel specimen. However, leak paths re-opened in most cases. The self-wastage patterns were not affected by the sodium temperature in the re-opened specimen. The diameter of the defected area, including the re-opened part, was about 5 min. It took 143, 40.7 and 34.7 minutes to re-open the leak path at 450, 475, and $510^{\circ}C$, respectively. It was concluded that the reopening time decreased with the increasing temperature.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.674-679
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• 1998

Small water leak experiment was carried out in liquid sodium atmosphere using a specimen of ferrite steel, which will be expected to be a material of the heat transfer tube of liquid metal fast breeder reactor. Self-plugging phenomena of leak path could be explained by the products of reaction and corrosion by sodium-water reaction. Also, re-opening mechanism of self-plugged path could be explained by the thermal transient and vibration of heat transfer tube. As a result, perfect re-opening time of self-plugged leak path was observed to be 129 minutes after water leak initiation. Re-opening shape of a specimen was appeared with double layer of circular type, and re-opening size of this specimen surface was about 2 mm diameter on sodium side.

• Journal of Sensor Science and Technology
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• v.28 no.5
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• pp.311-317
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• 2019

Rotating devices are commonly installed in power plants and factories. This study proposes a self-powered sensor node that is powered by converting the vibration energy of a rotating device into electrical energy. The self-powered sensor consists of a piezoelectric harvester for self-power generation, a rectifier circuit to rectify the AC signal, a sensor unit for measuring the vibration frequency, and a circuit to control the light emitting diode (LED) lighting. The frequency of the vibration source was measured using a piezoelectric-cantilever-type vibration frequency sensor. A green LED was illuminated when the measured frequency was within the normal range. The power generated by the piezoelectric harvester was determined, and the LED operation was assessed in terms of the vibration frequency. The piezoelectric harvester was found to generate a power of 3.061 mW or greater at a vibration acceleration of 1.2 g ($1g=9.8m/s^2$) and vibration frequencies between 117 and 123 Hz. Notably, the power generated was 4.099 mW at 122 Hz. As such, our self-powered sensor node can be used as a module for monitoring rotating devices, because it can convert vibration energy into electrical energy when installed on rotating devices such as air compressors.

• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3127-3129
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• 2011

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.899-910
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• 2016

The purpose of this study was to determine factors related to the consumption of energy drinks among male and female high school students in Daejeon. The research data, derived from the self-administered questionnaire method, was collected from 664 students in fifteen high schools during the spring of 2016. A total of 542 complete questionnaires were analyzed (response rate: 79.8%). Approximately 73% of the students self-reported having consumed energy drinks, with a greater percentage of male (as opposed to female) students self-reporting as having done so. The most common reasons given for the consumption of energy drinks were to stay awake (54.8%), the good taste of the drink (28.0%), to concentrate during studying (17.2%), and to relieve fatigue (16.9%). The adverse effects were palpitation (59.3%), insomnia (35.6%), and experiencing difficulty in waking up (30.5%). More than two in three (67.8%) students who experienced adverse effects still consumed energy drinks. The average level of health consciousness was lower than 3 out of 5 points. The results of the logistic regression analyses indicated a positive relationship between monthly allowance (OR=1.01 for male and female students) and the consumption of energy drinks by both male and female students. Among the male students, freshmen (OR=0.23) were less likely to have consumed energy drinks than juniors. Male students' sleeping hours (OR=0.65) and perceived school life satisfaction scores (OR=0.63) were negatively associated with the consumption of energy drinks. In the case of female students, study hours (OR=0.83) and energy drinks consumption were negatively related. These factors affecting energy drinks consumption could be considered in the development of dietary education programs aimed at protecting high school students from the adverse health impacts of energy drinks.

• Ceramist
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• v.22 no.2
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• pp.122-132
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• 2019

Wearable electronic devices with batteries must be lightweight, flexible and highly durable. Most importantly, the battery should be able to self-generate to operate the devices without having to be too frequently charged externally. An eco-friendly energy harvesting technology from various sources, such as solar energy, electromagnetic energy and wind energy, has been developed for a self-charging flexible battery. Although the energy harvesting from such sources are often unstable according to the surrounding environment, the energy harvesting from body movements and vibrations has been less affected by the surrounding environment. In this regard, flexible piezoelectric modules are the most attractive solution for this issue, because they convert mechanical energy to electrical energy and harvest energy from the human body motions. Among the various flexible piezoelectric modules, piezoelectric nanofibers have advantages when used as an energy harvester in wearable devices, due to their simple manufacturing process with good applicability to polymers and ceramics. This review focused on diverse flexible piezoelectric nanofibers and discusses their applications as various energy harvesting systems.

• Journal of Korean Academy of Nursing
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• v.30 no.5
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• pp.1145-1155
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• 2000

The purpose of this study is to explore the concept spirituality and to gain understanding of nursing intervention that may improve spiritual well-being. The concept analysis framework developed by Walker and Avant (1995) was used to clarify the concept. In the study, 'Harmonious interconnectedness', 'Transcendence', 'Integrative Energy' and 'Purpose and Meaning in Life' emerged as the critical attributes of spirituality. The first attribute, 'harmonious Inter- connectedness', has three categories including intrapersonal, (self), interpersonal (others/ nature) and transpersonal (the Supreme Being). The second attribute, 'Transcendence', is defined as the ability to extend one's own self beyond the limits of usual experiences and to achieve new perspectives. This attribute is demonstrated by 'coping with situations', to 'self-healing', and 'transformation'. The third attribute of spirituality is 'Integrative Energy', which integrates all dimensions and acts as a creative and dynamic force that keeps a person growing and changing. 'Integrative Energy is also defined as an inner resource that gives a sense of empowerment. Therefore the highly spiritual person demonstrate 'inner peace', 'growing', 'inner strength,' and 'well-being'. The fourth attribute 'Purpose and Meaning in Life' represents a sense of connectedness with one's inner values and with a greater purpose in life. It is demonstrated by 'hope' and 'a powerful life'. In this study, the antecedents of the spirituality represented as 'spirit' and its potential enablers were 'Introspection/reflection', 'Interconnectedness with all living things', and an 'Awareness of a Higher-Power'. The consequences of this concept may be described as 'physical, psychosocial, and spiritual well-being'. Empirical referents of this are 'purposeful life' 'self-worth' 'hope' 'love' 'service' 'forgiveness' 'trust/belief' 'inner peace' 'self-actualization' 'religious practices' 'transformation' 'inner strength' and 'coping'. In conclusion, spirituality can be defined based on these critical attributes. Spirituality is a dynamic, integrative energy based on a feeling of harmonious interconnection with self, others and a higher power. Through it, one is enabled to transcend and to live with meaning and purpose in life.

• Computers and Concrete
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• v.17 no.5
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• pp.597-612
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• 2016

The present work focuses on the use of coconut fiber in self compacting concrete. Self-Compacting Concrete (SCC) is a highly flowable, stable concrete which flows readily into place, filling formwork without any consolidation and without undergoing any significant segregation. Use of fibers in SCC bridge the cracks and enhance the performance of concrete by not allowing cracks to propagate. They contribute to an increased energy absorption compared to plain concrete. Coconut fiber has the highest toughness among all natural fibers. It is known that structures in the seismic prone areas are always under the influence of cyclic loading. To justify the importance of strengthening SCC beams with coir fiber, the present work has been undertaken. A comparison is made between cyclic and static loading of coconut fiber reinforced self compacting concrete (FRSCC) members. Using the test data obtained from the experiment, hysteresis loops were drawn and comparison of envelope curve, energy dissipation, stiffness degradation were made and important conclusions were draw to justify the use of coconut fiber in SCC.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.124-130
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• 2011

In this paper, We design and implementation of Self-Charging Module for charging to battery which obtaining the environment inergy such as solar energy. The power chared battery through the charging module send to sensor node. And implementation of System Activation Module(SAM) based on ID system and Dynamic Power Management Module(DPM) with SPO(Self Power Off). This system consume power only communication between the sensor nodes. We verification this system by implementing the high efficiency poweer management system.