• Korean Journal of Environmental Agriculture
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• v.37 no.1
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• pp.1-8
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• 2018

BACKGROUND: Different physical and chemical properties of biochar, which is made out of a variety of biomass materials, can impact water movement through amended soil. The objective of this research was to develop a decision support tool evaluating the impact of the shape and the size distribution of biochar on soil saturated hydraulic conductivity ($K_{sat}$). METHODS AND RESULTS: Plastic beads of different size and morphology were compared with biochar to assess impacts on soil $K_{sat}$. Bead and biochar were added at the rate of 5% (v/w) to coarse sand. The particle size of bead and biochar had an effect on the $K_{sat}$, with larger and smaller particle sizes than the original sand grain (0.5 mm) decreasing the $K_{sat}$ value. The equivalent size bead or biochar to the sand grains had no impact on $K_{sat}$. The amendment shape also influenced soil hydraulic properties, but only when the particle size was between 3-6 mm. Intra-particle porosity had no significant influence on the $K_{sat}$ due to its small pore size and increased tortuosity compared to the inter-particle spaces (macro-porosity). CONCLUSION: The results supported the conclusion that both particle size and shape of the amended biochar impacted the $K_{sat}$ value.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.3
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• pp.1-10
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• 1988

A higher order plate bending finite element using cubic in-plane displacement profiles is proposed for geometrically nonlinear analysis of thin and thick plates. The higher order plate bending element has been derived from the three dimensional plate-like continuum by discretization of the equations of motion by Galerkin weighted residual method, together with enforcing higher order plate assumptions. Total Lagrangian formulation has been used for geometrically nonlinear analysis of plates and consistent linearization by Newton-Raphson method has been performed to solve the nonlinear equations. The element characteristics have been computed by, selective reduced integration technique using Gauss quadrature to avoid shear locking phenomenon in case of extremely thin plates. Several numerical examples were solved with FEAP macro program to demonstrate versatility and accuracy of the present higher order plate bending element.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4719-4725
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• 2013

In this paper, we propose that a model based design for an electric motor cycle system using Automotive Simulation Models. Before prototyping a realistic electric motorcycle, a reliable simulation program is required to test the capacities of the power sources and optimize the parameters of an electric motorcycle. In the past, The research of electric motorcycle was conducted at macro rather than micro level. However, this research suggests the detailed analysis method of specific key components. This paper can get a good error ratio, 2.3%, as a consequence of the interpretation of experiment and simulation. With the analysis of specific electric motorcycle, it is able to analyze design factor and improve accuracy of electric motorcycle interpretation. Also, this research suggests the effective way to get fail safety so that it can solve the fail which can be encountered in electric motorcycle.

• The Journal of Korean Academic Society of Nursing Education
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• v.26 no.3
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• pp.281-289
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• 2020

Purpose: This study aimed to confirm mediating effects of academic self-efficacy in the relationship between academic stress and sleep quality among academic high school students. Methods: The participants included 195 academic high school students who were attending a private educational institution in the Gwangju or Pusan metropolitan city. Data were collected from September 1 to September 30, 2019. The data were analyzed using PROCESS macro SPSS/WIN 3.2 and bootstrapping was used to test the mediating effects. Results: There were significant relationships between sleep quality and academic stress (r=-.55, p<.001), sleep quality and academic self-efficacy (r=.35, p<.001), and academic stress and academic self-efficacy (r=-.16, p<.020). Academic self-efficacy showed partial mediating effects in the relationship between academic stress and sleep quality. Conclusion: These findings suggest that the development of a program that improves the academic self-efficacy of academic high school students who are experiencing academic stress is a way to improve the quality of their sleep.

• Smart Structures and Systems
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• v.12 no.5
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• pp.579-594
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• 2013

A new enthalpy - based procedure for the homogenization of the electromechanical material parameters of composite piezoelectric modules with integrated electrodes is presented. It is based on a finite element (FE) modeling of the latter's representative volume element (RVE). In contrast to most previously published homogenization approaches that are based on averaged quantities, the presented method uses a direct evaluation of the electromechanical enthalpy. Hence, for the linear orthotropic piezoelectric composite behavior full set of elastic, piezoelectric, and dielectric material parameters, 17 load cases (LC) are used where each load case leads directly to one material parameter. This gives the possibility to elaborate a very strict and easy to program processing. In conjunction with the 17 LC, the enthalpy - based homogenization is particularly suitable for laminated composite piezoelectric modules with integrated electrodes. In this case, the electric load has to be given at the electrodes rather than at the RVE FE model boundaries. The proposed procedure is validated through its comparison to literature available results on a classical 1-3 piezoelectric micro fiber (longitudinally polarized) reinforced composite and a $d_{15}$ shear piezoelectric macro-fiber (transversely polarized) composite module.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.466-478
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• 2017

The purpose of this study was to examine the relationships between perceived parental attachment and the life satisfaction of college students, focusing on the mediating role of psychological basic needs(autonomy, competence and relatedness). The Participants of this study were 208 college students. The result was statistically treated using SPSS 21.0 program, Amos 21.0. Additionally, PROCESS Macro was used to verify the significant mediating effect. Results from structural equation modeling analyses indicated that a research model produced a better fit to the data than a alternative structural model. The final SEM model fit indices of $x^2$(df), CFI, TLI, RMSEA were met the acceptable criteria of model fitness. In other words, among the goodness-of-fit indexes of the final study model, $x^2=261.075$(p<.001), RMSEA is .082, TLI equals .925, CFI equals .940. The results showed the following: First, Parental attachment has a direct effect on autonomy, competence and relatedness. Also competence and relatedness have a direct effect on the life satisfaction. Second, Competence and relatedness showed a mediating effects on Parental attachment and the life satisfaction. The implications of these results were discussed and the further studies were suggested.

• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.100-107
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• 2001

On the planning for the systematic management and control of the air pollution display methods were used to evaluate the spatial pollutant concentration status. This study were conducted to investigate the practical using of Geographic Information System(GIS) technology on the air pollution control and management which were computer-based systems that were used to store and manipulate geographic information in the macro city. In this study 137 samples were corrected by passive samplers and analysed by GC/MSD for 16 VOCs in Seoul (25 distincts) distributed by TM-coordinate(2 km$\times$2km), and finally displayed by Arciew program(version 3.2, ESRI Inc, USA) for windows. The concentration of benzene and toluene showed high level in whole area of seoul area of Seoul and distribution of butylbenzen, trothroloetylene, stylen showed high level in whole area of Seoul except a few distincts and the distribution of isopropylbenzene, 1,2-dichroloethane showed higher level in core area than that of Kangnam and Kangbuk area. In conclusion, products of this study of using GIS technology apply on the spatial distribution of VOCs concentration was very effective than that of other methods(e.g., contouring concentration method, pie or column chart, graduated symbols), especially in mapping and symbolization of pollution status evaluation.

• Human Ecology Research
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• v.57 no.3
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• pp.445-457
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• 2019

This study investigated the impact of parentification on ambivalence over the emotional expression of early adults who had a sibling with disabilities and examined if rejection sensitivity moderated the relationship of parentification and ambivalence over emotional expression. Participants consisted of 116 siblings in early adulthood who had a sibling with disabilities (45 male; 71 female). The data were collected from 13 centers for family disability, four community rehabilitation centers, three parent societies for people with disabilities, and three self-help groups in Seoul, Busan, and Gyeonggi province. The levels of ambivalence over emotional expression, parentification, and rejecton sensitivity were measured by the Ambivalence over Emotional Expression Questionnaire (King & Emmons, 1990), the Filial Responsibility Scale-Adult (Jurkovic, Thirkield, & Morrell, 2001), and the Rejection Sensitivity Questionnaire (Downey & Feldman, 1996), respectively. The PROCESS Macro program examined the moderating model. The Results indicated that both levels of parentification and rejection sensitivity increased the level of ambivalence over emotional expression of non-disabled siblings. In addition, rejection sensitivity moderated the effect of parentification on ambivalence over emotional expression. The influence of parentification on ambivalence over emotional expression was greater when the level of rejection sensitivity was high, compared to when it was low.

• Structural Engineering and Mechanics
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• v.78 no.2
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• pp.135-143
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• 2021

In this study, continuous contact problem in the functionally graded (FG) layer loaded with a FG flat punch resting on the elastic semi-infinite plane was analyzed by the finite element method (FEM). It was assumed that the shear modulus and density of the layer and punch varied according to exponentially throughout their depth. FG layer's weight was included to the problem and additionally all surfaces were considered as frictionless. Analysis of FG materials was performed with a special macro which was added to the ANSYS program. Firstly, the shear modulus of the punch was considered to be very rigid and the results of initial separation load (λcr) and distance (xcr) were compared with the analytical solution. Afterwards, results obtained from the contact analysis made according to the inhomogeneity parameters (β, γ) between FG punch-FG layer which had been unprecedented in the literature were discussed. As a result, FG punch's stress values at the punch edges where stress accumulations occurred were found to be smaller than the rigid punch. The security of the structure, longer life of the material and ease of production are directly related to the reduction of the stress values. The results obtained in this study are important in this respect. Also this work is the first study that investigates the effect of FG punch on the FG layer.

• Korean Journal of Childcare and Education
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• v.17 no.2
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• pp.121-142
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• 2021

Objective: The purpose of this study is to examine the mediating effect of teacher-child emotional, verbal, and behavioral interactions on the relationship between teacher playfulness and children's peer abilities. Methods: The research method used the questionnaire method to collect data on 420 children aged 3-5 years old, targeting 108 homeroom teachers working at early childhood education institutions located in Seoul and Gyeonggi area. The collected data was analyzed using the IBM SPSS 23.0 statistical program and the PROCESS macro of Hayes (2013). Results: This study confirmed that teachers' verbal, emotional, and physical interactions are closely related to young children's peer competence. In addition, it was confirmed that the teacher's playability is an important variable that affects not only the emotional, verbal, and physical interactions between the teacher and the infant, but also the peer competence of young children. Conclusion/Implications: The results of this study have significance as basic data that suggests that it is necessary to improve the playability of teachers and increase the quality level of the multifaceted aspects of teacher-infant interaction in order to support young children's peer competence.