• Geomechanics and Engineering
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• v.31 no.5
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• pp.461-476
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• 2022

Research studies on the scale effect on triaxial strength of intact rocks are scarce, being more common those in uniaxial strength. In this paper, the authors present and briefly interpret the peak and residual strength trends on a series of triaxial tests on different size specimens (30 mm to 84 mm diameter) of an intact granitic rock at confinements ranging from 0 to 15 MPa. Peak strength tends to grow from smaller to standard-size samples (54 mm) and then diminishes for larger values at low confinement. However, a slight change in strength is observed at higher confinements. Residual strength is observed to be much less size-dependent. Additionally, this study introduces preliminary modelling approaches of these laboratory observations with the help of three-dimensional particle flow code (PFC3D) simulations based on bonded particle models (BPM). Based on previous studies, two modelling approaches have been followed. In the first one, the maximum and minimum particle diameter (D_max and D_min) are kept constant irrespective of the sample size, whereas in the second one, the resolution (number of particles within the sample or ϕ_v) was kept constant. Neither of these approaches properly represent the observations in actual laboratory tests, even if both of them show some interesting capabilities reported in this document. Eventually, some suggestions are provided to proceed towards improving modelling approaches to represent observed scale effects.

• Journal of Korean Home Economics Education Association
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• v.10 no.2
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• pp.1-11
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• 1998

The purpose of this study is to analyze highschool girls' concerns about environmental problems after investigating the actual state of environmental education and to suggest some fundamental changes in the Home Economics classes to improve environmental education. The sample was selected form high school girl students in Kyounggi Province between September 16 and September 26, 1996. Eight hundred twenty (820) first and second grade respondents were used. The data were analyzed by frequency, mean, percentile, factor analysis. Duncan's Multiple Range Test, and Stepwise Multiple Regression. Based on the major findings, the most influential variable was parental attitudes towards environmental conservation and problem. Next in influence was the environmental education provided in Home Economics classes. Also important were the individual student's interest in Home Economics classes, and her belief in the utility of environmental conservation in everyday life. The research conclusions are as follows: 1. We'll find how to relate efficiently the environmental education with everyday life by analyzing thoroughly the text of home economics. 2. We'll develop how to educate students parents properly because parental attitudes to wards the environmental problem have a great effect on students' behaviors. 3. We'll ceinforce environmental education by developing problems, and to motivate them to take real action in the area of environmental conservation.

• Hwankyungkyoyuk
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• v.24 no.1
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• pp.12-25
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• 2011

The purpose of this study was intended to identify the difference of two sample groups for the student's awareness on the environment after ecological education in elementary school. For the elementary school participated in this study, we studied how the education influences the student's awareness on the environment using survey. The result showed that even though various kinds of environmental education programs were given to the participated group, there was no significance compared with the other group who did not participate. This was probably because the students not participated in the education program were frequently exposed to other similar types of environmental activities. In terms of the change of the student's awareness on the environment and their desire for continuing environmental education in future, 95.8% of students who participated in the survey showed positive answers. Considering the current environmental education that has mostly been made in class and the lack of variety of the education program, various types of environmental education programs are required, so schools, education system, and social groups should work together to compensate for the lack of the in-class education. In addition, the change of students awareness and altitude toward the environment proved the positive effect of the environmental program and showed the appropriateness increasing the opportunity for the environmental education.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.6
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• pp.654-661
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• 2007

The goal of this research was to identify the impact of silicate polymerization on the formation of insoluble aluminiumsilicate salts which could be a cause of irreversible fouling in the membrane process by lab-scale test. For this, the amount and characteristics of precipitates that were formed in six samples with different Al and Si concentration were analyzed. And the particles was also observed by SEM-EDS(Scanning Electron Microscope - Electron Dispersion Spectrophotometer) to compare morphology and ratio of Al and Si in each precipitates. Finally the reactive and nonreactive silicate contents in the solution and precipitates were analyzed to calculate silicate form content in each fraction. The amount of precipitates was in proportion to the total concentration of both element in solution. And the amount of insoluble particle that was not dissolved in the acid solution was recorded the highest in the sample 2 of which Si concentration was lower than the saturation concentration, 50 mg/L. The content of reactive silicate in precipitates was also recorded the highest value in sample 2 of which almost silicate form was reactive. When the silicate concentration is same, that value was recorded the highest in the sample with highest Al concentration. The SEM morphology of the precipitates was similar to that of Aluminiumhydroxide and the insoluble precipitates was not dissolved in acidic solution with pH 2.7 was able to observed only in sample 2. The ratio of Al and Si in the precipitates was ranged $0.48\sim3.14$, thai of sample 2 was recorded the highest value, 3.14. It is concluded that the insoluble aluminiumsilicate could be easily formed in the solution of which silicate exist as a reactive form and coexisting Al is sufficient.

• Korean Journal of Human Ecology
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• v.7 no.4
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• pp.99-113
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• 2004

The purpose of this study to find out of the middle school students' knowledge, consciousness and behavior of the environmental problems. The sample of this study were 489 middle school students in Busan area. The collected data were statistically analized by using SPSS program. The major findings were as follows: 1. The level of middle school students' consciousness of environmental problems is 4.07 out of perpect 5. The highest was waste pollution(M=4.35), and the lowest was noise pollution(M=3.39). The level of middle school students' behavior of environmental problems is 3_49 out of perpect 5, which is somewhat lower than the consciousness of environmental problems. The highest was air pollution(M=4.11), and the lowest was water pollution(M=3.23). 2. The middle school students' consciousness and behavior of environmental problems showed passive corelation$(P<.01)$ : The higher the consciousness of environmental problems is better the behavior of environmental problems. 3. The level of middle school students' knowledge of environmental problems showed notable difference with sex$(P<.01)$ and a school year$(P<.05)$.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1162-1166
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• 2008

In this paper, several parameters affecting the sensitivity and determining the minimum detectable activity (MDA) for the measurement of the Pu isotopes were investigated. Among the parameters affecting the determination of the MDA values for the Pu isotopes in the environmental samples, amounts of the samples appeared to be crucial factors in decreasing the MDA values. The MDA for the Pu isotopes in the environmental samples were calculated by varying the counting time of the samples and background. The results obtained in this study can be used for an environmental radiation monitoring program regarding the level of concern for a radionuclide beyond which some action may need to be taken.

• Korean Journal of Organic Agriculture
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• v.13 no.2
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• pp.145-159
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• 2005

The objectives of this study were to analysis satisfaction and additional cost scale about environmental-friendly agri-product school meal program. To analysis satisfaction about environmental-friendly agri-product (EFAP), parent' survey were conducted residing in Cheonan city. The sample size of the survey is 304 respectively. As a result, parents of students recognized that EFAP is good for their children as well as they really want to change food material from general agri-product to EFAP. Therefore, environmental-friendly agri-policy to be more focused on consumption behavior and food security needs. In order to perfectly change food material to EFAP, about l trillion won will be additionally needed. It means that the market demand of EFAP will be dramatically increased. On the other hand, safe school meal program is one of the most important in a child's life, vital for proper growth and development.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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• pp.327-328
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• 2005

Trace anions in high-sulfate wastewater from mainly derelict mines were determined by ion chromatography with on-line preconcentration and preelution technique. As the sample was preconcentrated and more strongly held ions were preeluted to the principal separation system, this approach was highly effective in removing large concentration of sulfate in high-sulfate wastewater. With this practical on-line preelution treatment, the peaks of fluoride and chloride showed good resolution even when the sulfate concentration was as high as 2000 mg/L and the analyzed total metal concentration was above 500 mg/L.

• Journal of Information Technology Services
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• v.13 no.3
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• pp.1-23
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• 2014

This study investigates the effect of technological and environmental factors on the cloud computing assimilation, which then affects firms' performance. The technological characteristics include cost-savings, technology use advantage, technology infrastructure, and technology compatibility while environmental characteristics include partner cooperation, competitive pressure, environmental uncertainty, and business agility. Furthermore, we examine inter-organizational trust as a moderating effect between environmental characteristics and cloud computing assimilation. Data from a sample of 219 firms show the significant impacts of proposed variables with exception of technology infrastructure and technology compatibility. The findings also show that inter-organizational trust has a significant moderating effect in all paths except the one between business agility and cloud computing assimilation. The implication of this study suggests a theoretical framework explaining cloud computing assimilation and performance within inter-organizational environment.

• Journal of environmental and Sanitary engineering
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• v.17 no.4
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• pp.1-9
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• 2002

In order to define about concern with discharge and water-quality, it is calculated drought flow, low flow, normal flow and wet flow in Chungju watershed from flow duration analysis. Water quality modeling study is performed for forecasting at upstream of Chungju lake. It is devided method of modeling into before and after the equipment of environmental treatment institution. And it is estimated the change of water quality. Before the equipment of environmental treatment, BOD concentration is increased from 23000 to 2006 years at all site and decrease on 2012 years. The rate of increasing BOD concentration is showed height between 2000 years and 2003 years most of all site. And after the equipment of environmental treatment, it is showed first grade of BOD water quality in most of sample site beside Jucheon river. The result of water quality modeling using drought flow showed that a lot of pollution occurred. And water quality using wet flow is good, so much discharge make more improve water quality than little discharge.