• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1037-1049
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• 2017

The purpose of this study is to explore how the flow of discourse move and their reasoning process in dialogic argumentation during group modeling on excretion. Five groups of three to four students in the second grade of a middle school participated in the modeling practice of a Gifted Center. Analysis was conducted on argumentation during the modeling activity in which students should explain how the waste product (ammonia) leaves the body. It was found that there was a sequential argumentative process-tentative consensus, solving the uncertainty, and consensus. There were several discourse moves - 'claim' and 'counterclaim' in the stage of tentative consensus, 'query' and 'clarification of meaning' in the stage of solving the uncertainty, and 'change of claim' in the stage of consensus. Students participated in the dialogic argumentation by constructing argument collaboratively for reaching a consensus. Critical questioning in the stage of solving the uncertainty and reasoning in the stage of consensus were the impact factors of dialogic argumentation. By answering the critical questions, students changed their claims or suggested new claims by defending or rebutting previous claims. Students justified group claims with diverse argumentation scheme and scientific reasoning to reach a group consensus. These findings have implication for science educators who want to adopt dialogic argumentation in science classes.

• Korean Educational Research Journal
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• v.38 no.3
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• pp.167-188
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• 2018

The purpose of this study is to suggest safety education on life science inquiry activity, which subjects on the exploration and autonomous research to the relevant topics, mainly done by the science high school students. Investigation was made on subjects of research activity proposed from Life science and autonomous research from science high school students by examine thoroughly 2009 revised education curriculum. To prevent school laboratory accidents, education of basic safety regulations and general precautions should be repeatedly notified by clear statements and expression to each topic. Expressing the safety factors considering the themes of autonomous inquiry and activities presented in the course of education should be done, so that students should not experience laboratory accidents by reason of ignorance. From the beginning of organization to performing research, safety rules about disposing chemicals and tools wastes occurring during research should be noticed and expressed in precautions following waste disposal system should be adopted. It is necessary to level up the accessibility of information about the laboratory safety rules to confirm to the every student, and also ensure the takeover of the clean-up and use of utilities at the time of search end in order to prevent the incidence of laboratory accidents during the thorough stages of biological inquiry activities.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1119-1122
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• 2006

Aeration by using diffusers usually requires approximately 50~90% of the total electricity needed to operate WWTP (WasteWater Treatment Plant)s. Accurate evaluation of the oxygen transfer efficiency for an aeration system, and recommendation of a better alternative may help saving WWTP operational costs. Appropriate techniques and methods to achieve this purpose have not been introduced in Korea. In this study, in-process analysis was performed for a coarse bubble aeration system by the off-gas method to evaluate its applicability in Korea. To accomplish this analysis, an off-gas test, unsteady-state clean water test and steady-state off-gas column test was conducted and comparisons to other aeration systems were made. The ${\alpha}$ and the F estimated from the results of the unsteady-state clean water test and the steady-state off-gas column test were 0.61 and 0.90 respectively in a coarse bubble aeration system. The comparison of P.E tube diffusers laid out single spiral roll and ceramic dome diffusers laid out full floor coverage showed that the oxygen transfer efficiency of the coarse bubble aeration system was less than or similar to other aeration systems. But, airflow rates per unit area were 4~5 times greater than other aeration systems. In regards to the oxygen transfer efficiency for airflow rates per unit area, a retrofit to higher efficiency diffusers was urgently needed. This study showed proved that off-gas methods can apply to evaluate diffuser performances to estimate operating factors and to compare other aeration systems in Korea.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.92-99
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• 2020

Linked treatment refers to a system that relieves the burden of the business by linking high concentrations of wastewater such as human waste, manure, leachate, and other industrial wastewater to nearby municipal wastewater treatment plants(MWTPs). In 2018, 187 MWTPs, which are about 4.5% of the total domestic MWTPs, have implemented a linked treatment system, but local governments are having difficulties in operating sewage treatment due to lack of reasonable cost estimation standards. Therefore, we proposed an improvement plan to solve the problem in the calculation method that currently imposes linked wastewater. To this end, the effects and correlations of the linkage treatment system on the sewage treatment unit were analyzed, and among them, the main factors with the highest correlation were applied to the improvement plan. As a result, an improvement plan that improved three parts of the existing calculation method was presented, and the calculation method and the calculation case using the existing literature values were also presented. This can be used as a basis for future reference by local governments to implement linkage treatment, and to revise local sewerage ordinance and is believed to be helpful in operating a rational linkage system.

• Resources Recycling
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• v.17 no.4
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• pp.47-56
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• 2008

The aim of this study is to produce cokes which can be used for the production of ferroalloy, for this purpose, domestic anthracite mixed with plastic was sintered at various condition. The combustion and physical properties of anthracite and plastic, coal separation, and the influence of factors on the strength of coke were investigated. The results of this study are as follows: 1. The three kinds of anthracite from the Samcheok region contained 25 to 30% ash of $100{\mu}m$ over size, and have the caloric value of 5,205 cal/g(TaeAn), 4,893 cal/g(JangSung), 4,873cal/g(KyongDong). 2. The recommendable conditions for heavy-fluid separation of the Samcheok coal are to set the specific gravity of heavy fluid to 2.4 and control the size of coal to $35{\sim}140mesh$. 3. It is concluded that phenolic resin powder, liquefied phenolic resin, SAN, and melamine resin can be used as a binder for the anthracite cokes, from the thermal analysis of various plastics. Especially, the liquefied phenolic resin was considered as the most suitable binder as it would simplify the process.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.60-69
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• 2020

Purpose: Cavity growth process monitoring is to periodically monitor changes in common size and topography for general and observational grades to predict the rate of common growth. The purpose of this study is to establish a systematic cavity management plan by evaluating the general and observational class community in a non-destructive method. Method: Using GPR exploration equipment, the acquired surface image and the surrounding status image are analyzed in the GPR probe radargram in depth, profile, and cross section of the location. The exact location is selected using the distance and surrounding markings shown on the road surface of the initial detection cavity, and the test cavity is analyzed by calling the radar at the corresponding location. Result: As a result of monitoring tests conducted at a cavity 30 sites of general and observation grade, nine sites have been recovered. Changes in scale were seen in 21 cavity locations, and changes in size and grade occurred in 13 locations. Conclusion: The under road cavity is caused by various causes such as damage to the burial site, poor construction, soil leakage caused by groundwater leakage, waste and ground vibration. Among them, indirect factors could infer the effects of groundwater and localized rainfall.

• Tunnel and Underground Space
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• v.24 no.4
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• pp.297-307
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• 2014

Cavern Thermal Energy Storage system stores thermal energy in caverns to recover industrial waste heat or avoid the sporadic characteristics of renewable-energy resources, and its advantages include high injection-and-extraction powers and the flexibility in selecting a storage medium. In the present study, the structural stability of rock mass pillar between these silo-type storage caverns was assessed using a coupled thermal-mechanical model in $FLAC^{3D}$. The results of numerical simulations showed that thermal stresses due to long-term storage depended on pillar width and had significant effect on the pillar stability. A sensitivity analysis of main factors indicated that the influence on the pillar stability increased in the order cavern depth < pillar width < in situ condition. It was suggested that two identical caverns should be separated by at least one diameter of the cavern and small-diameter shaft neighboring the cavern should be separated by more than half of the cavern diameter. Meanwhile, when the line of centers of two caverns was parallel to the direction of maximum horizontal principal stress, the shielding effect of the caverns could minimize an adverse effect caused by a large horizontal stress.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.439-455
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• 2019

A buffer is the major component of a high level radioactive waste repository. Due to their thermal conductivity and low permeability, bentonites have been considered as a key component of a buffer system in most countries. The deep geological condition generates ground water inflow and results in swelling pressure in the buffer and backfill. Investigation of swelling pressure of bentonite buffer is an important task for the safe disposal system. The swelling pressure that can be critical is affected by mechanical and hydro properties of the system. Therefore, in this study, a sensitivity analysis was conducted to examine the effect of hydro-mechanical (HM) behaviors in the MX-80 bentonite. Based on the results of the swelling pressure generation with HM model parameters, a coupled HM analysis of an unsaturated buffer and backfill in a deep geological repository was also carried out to investigate the major factor of the swelling pressure generation.

• Journal of Veterinary Clinics
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• v.28 no.2
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• pp.219-224
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• 2011

The health status of three groups of Hanwoo steers (n=157) aged 2-3 years, raised at three different altitudes (600 m, n=50; 200-400 m, n=58; plane land, n=49) and environment with more or less similar management have been evaluated through hematological, biochemical and globulin examinations in order to determine the optimum environment suitable for raising cattle while at the same time minimizing the risk of disease. Five mL of blood samples from each animal were collected by jugular veinipuncture and 2 mL was transferred to a tube containing EDTA for complete blood count (CBC) and 3 mL in lithium heparin for chemistry screening (CS) and immunoassay. Among the CBC parameters a significantly higher white blood cell count (tWBC), total red blood cell count (tRBC), hemoglobin (Hb) and packed cell volume (PCV) were noticed in the high altitude groups, whereas those were lower in the plane land group. In the CS parameters higher levels of aspartate aminotransferase (AST), creatinine, lactate dehydrogenase (LDH) and total bilirubin (TBL) were found in the plane land group, whereas those were lower in the high altitude groups. The total protein (significantly) and globulins were higher in the 600 m group. The results of this study revealed that the overall health status of the Hanwoo cattle based on the hemato-biochemical indices was superior in the highest altitude and inferior in the plane land group but all the parameters were within the reference range in all the groups. Therefore, for recommendation of a suitable environment at an appropriate altitude for raising cattle there need to be further studied along with the hemato-biochemical parameters; considering, breeding, feeding, management, marketing, waste disposal and other factors.

• Analytical Science and Technology
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• v.12 no.4
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• pp.299-305
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• 1999

The electrolyte cathode atomic glow discharge (ELCAD) is a new plasma source for direct determination of trace heavy metals in drinking and waste water. ELCAD has been successfully developed for on-line monitoring of heavy metals, however, shows difficulty to measure mercury. In this study, ELCAD has been modified to apply the atomic absorption spectrometry (AAS) for the direct determination of trace elements of mercury in flowing water.The fundamental characteristics of this new types of plasma source have been investigated and found that the pH of the solution, discharge voltage, and current are most important factors.The absorbance of 1.0 ppm Hg standard solution increases as pH of the solution increases from pH 1.0 to 3.0.However, % RSD of the absorbance also increases as the pH of solution increasesdue to plasma unstability.The detection limits of the standard solution of pH 1.5 and pH 3.0 are about 40 ppb and 10 ppb level, respectively.