• Journal of Environmental Science International
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• v.19 no.9
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• pp.1119-1127
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• 2010

The behavior of copper throughout the whole process of wastewater treatment plant that uses the activated sludge process to treat the wastewater of petrochemical industry that contains low concentration of copper was investigated. Total inflow rate of wastewater that flows into the aeration tank was $697\;m^3$/day with 0.369 mg/L of copper concentration, that is, total copper influx was 257.2 g/day. The ranges of copper concentrations of the influent to the aeration tank and effluent from the one were 0.315 ~ 0.398 mg/L and 0.159 ~ 0.192 mg/L, respectively. The average removal rate of copper in the aeration tank was 50.8 %. The bioconcentration factor (BCF) of copper by microbes in the aeration tank was 3,320. The accumulated removal rate of copper throughout the activated sludge process was 71.3%, showing a high removal ratio by physical and chemical reactions in addition to biosorption by microbes. The concentration of copper in the solid dehydrated by filter press ranged from 74.8 mg/kg to 77.2 mg/kg and the concentration of copper by elution test of waste was 2.690 ~ 2.920 mg/L. It was judged that the copper concentration in dehydrated solid by bioconcentration could be managed with the control of that in the influent.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.11 s.116
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• pp.1100-1107
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• 2006

As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by chamber volume. In this study, transmissibility behavior of the pneumatic isolators depending on frequency and dynamic amplitude are presented. Then, an active control technique, time delay control, which is adequate for a low frequency nonlinear system, is applied. A procedure of applying the time delay control law to a pneumatic isolator is presented and it's effectiveness in the transmissibility performance is shown. Comparison between passive and active pneumatic isolators is made based on simulation.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.837-843
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• 2006

As environmental vibration requirements on precision equipment become more stringent, use of pneumatic isolators has become more popular and their performance is subsequently required to be further improved. Performance of passive pneumatic isolators is related to various design parameters in a complicated manner and, hence, is very limited especially in low frequency range by chamber volume. In this study, transmissibility behavior of the pneumatic isolators depending on frequency and dynamic amplitude are presented. Then, an active control technique, time delay control, which is adequate for a low frequency nonlinear system, is applied. A procedure of applying the time delay control law to a pneumatic isolator is presented and it's effectiveness in the transmissibility performance is shown. Comparison between passive and active pneumatic isolators is made based on simulation.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.4
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• pp.433-441
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• 2004

This paper presents a strategy for the quality assurance of the continuous preflex composite girder bridge through the camber management of the girder during construction. The construction stages which require welding, balanced preflexion loads at the ends, etc. may cause unexpected large deformation to the preflex girder. Furthermore, these defects can be detected by measurements and analyses of the girder behavior which is sometimes time consuming. In the present study, preflex girder's camber data at equally spaced nodes in each construction stage are obtained and analyzed for the quality control of thee span continuous preflex girder composite bridge.

• Steel and Composite Structures
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• v.24 no.3
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• pp.339-349
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• 2017

In this paper, a conventional refined plastic hinge analysis is improved to account for the effects of local buckling and lateral-torsional buckling. The degradation of flexural strength caused by these effects is implicitly considered using practical LRFD equation. The second-order effect is captured using stability functions to minimize modeling and solution time. An incremental-iterative scheme based on the generalized displacement control method is employed to solve the nonlinear equilibrium equations. A computer program is developed to predict the second-order inelastic behavior of space steel frames. To verify the accuracy and efficiency of the proposed program, the obtained results are compared with the existing results and those generated using the commercial finite element package ABAQUS. It can be concluded that the proposed program proves to be a reliable and effective tool for daily use in engineering design.

• Journal of Korean Public Health Nursing
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• v.31 no.1
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• pp.121-134
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• 2017

Purpose: The goal of this study was to define and clarify the concept of "self management" of children with chronic diseases. Methods: For analyzing the concept of self management, this study used the hybrid model. This study involved in-depth interviewing nine children with chronic disease. Results: The concept of self management of children with chronic disease can be categorized with three dimensions: internal, environmental, and behavioral aspects. Besides, five attributes and thirteen indicators were analyzed. The concept of self management of children with chronic disease can be expressed as a kind of process; a) re-established yourself (internal dimension), b) assistance by the surrounded (environmental dimension), and c) positive health management behavior with self control of daily life (behavioral dimension). Conclusion: The self management is important for children with chronic disease to control their disease for long time. The attributes and indicators drawn by this study could be used for tool development and useful resources of self management competence in children with chronic disease.

• Journal of Environmental Science International
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• v.11 no.12
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• pp.1315-1320
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• 2002

Since the enzymatic degradation of microbial poly[(R)-3-hydroxybutyrate-co-3-hydroxyvalerate] (P(3HB-co-3HV)) initially occurs by a surface erosion process, a degradation behavior could be controlled by the change of surface property. In order to control the rate of enzymatic degradation, plasma gas discharge and blending techniques were used to modify the surface of microbial P(3HB-co-3HV). The surface hydrophobic property of P(3HB-co-3HV) film was introduced by CF$_3$H plasma exposure. Also, the addition of small amount of polystyrene as a non-degradable polymer with lower surface energy to P(3HB-co-3HV) has been studied. The enzymatic degradation was carried out at 37 $^{\circ}C$ in 0.1 M potassium phosphate buffer (pH 7.4) in the presence of an extracellular PHB depolymerase purified from Alcaligenes facalis T1. Both results showed the significant retardation of enzymatic erosion due to the hydrophobicity and the enzyme inactivity of the fluorinated- and PS-enriched surface layers.

• Journal of The Korean Association For Science Education
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• v.16 no.1
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• pp.97-102
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• 1996

Attitude is considered one of the most important influences on behavior and is defined as an enduring positive or negative feeling about some person, object or issues. The teaching strategies for affective domain are needed to develop the positive attiudes about environments. One of them is to faciliate the involvement of emotional feedback. The purpose of this study was to verify the effects of emotional feedback. Cognitional feedback was carried to control group but cognitional and emotional feedback were carried concurrently to experimental group. By the results, post test scores of experimental group were significantly higher than those of control group about four goals of Environmental Education, respectively. Therefore this strategy is effective to achieve goals of affective domain. Also, emotional feedback is important factor to raise the achievement of cognitive domain, too.

• Journal of East-West Nursing Research
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• v.29 no.2
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• pp.161-171
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• 2023

Purpose: The purpose of this study is to verify the effectiveness of the Environmental Hazards Exposure Prevention Program for Mothers with Young Child (EHEPP-MYC) and to provide basic data for environmental health projects in the community. Methods: EHEPP-MYC was developed based on the protection motivation theory. A quasi-experimental design was applied to evaluate the effectiveness of the program. The number of study participants was 30 in the experimental group and 31 in the control group. The intervention applied to the experimental group consisted of lectures as the main method, current affairs programs, discussions, booklets, animations, and practical training. The program was held twice a week for a total of 4 sessions of 60 minutes each. The effect of applying the program was measured three times through surveys (before, immediately after, and two weeks after the intervention) and analyzed through repeated measures ANOVA. Results: The EHEPP-MYC had significant effects on preventive behavior, perceived severity, perceived vulnerability, self-efficacy, response efficacy, and response costs at three time points. Conclusion: EHEPP-MYC has been shown to be effective in promoting environmental hazards prevention behaviors among mothers of young child. EHEPP-MYC can be used as baseline data for projects developing programs to prevent exposure to environmental hazards and improve the environmental health of communities.

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.931-951
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• 2015

To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.