• Fire Science and Engineering
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• v.22 no.1
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• pp.99-104
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• 2008

It is important to understand thermal characteristic as a method to estimate the new materials, because spontaneous ignition characterized by causing combustion in the low temperature without ignition source. If can not find out the thermal characteristics of materials, it is frequent that causes of fires could not be found. The danger level of spontaneous ignition material should be estimated and by closely studying its thermal characteristic. However, RPF(Refuse Paper & Plastic Fuel) is a solid matter and getting increasesa year by year because it is an economy profit as alternative energy for limited fossil fuels. Some time RPF occur a fire in the cases of its production process and conservation. Therefore study for thermal stability and critical ignition temperature of RPF was so imperative that the experiment by means of Bombe Calorimeter, TG-DTA, MS80, SIT-II, and Wire Basket Test was implemented. As a result, RPF had a caloric value 26.4-28.3 MJ/kg, and its initial pyrolysis temperature was $192^{\circ}C$ at heating rate 2 K/min. With the result of analysis by MS 80 which is an instrument measuring microscopic calory, pure RPF not containing water has higher caloric value than RPF containing 20% water. Also, SIT-II which is an instrument of insulated auto-ignition was ignited by $118.5^{\circ}C$. This temperature is lower than that of Wire Basket Test. The critical ignition temperature was calculated by Frank-Kamenetskii equation can cause ignition at $80^{\circ}C$ when conserved in the height of 10 m by the standard of infinity slab.

• Journal of Wetlands Research
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• v.12 no.3
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• pp.49-56
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• 2010

Euryale ferox is only annual hydrophyte among endangered plants in Korea and its seed is high valuable medicinal material. This studies were carried to find out key factors that made E. ferox endanger in Korea and to apply the results for effective management of the natural wetlands inhabited by E. ferox. We investigated the distributed sites reported by previous studies and classified the distribution-affected factors into three categories, eutrophication(hypothesis 1), soil accumulation(hypothesis 2) and increasing of water level(hypothesis 3) in the habitat. These three hypotheses were tested in the field and explained the results with the morphological characteristics of seed germination stages of E. ferox. The geographical distribution ranges of E. ferox diminished at a rate of $1^{\circ}$ latitude with about 10 natural wetlands for last 30 years. Water eutrophication in the wetland had a positive effect on the establishment of E. ferox. But higher in soil accumulation and water depth, then lower in the establishment rate of E. ferox. These results indicate that water depth in the wetland must be below 50cm during the germination season, especially in May and emergent hydrophytes filter zone is need to protect soil accumulation from soil erosion within its watershed for the effective management of wetland with E. ferox.

• Journal of Korea Water Resources Association
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• v.49 no.2
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• pp.83-94
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• 2016

Geomorphological, bed material and hydraulic characteristics are basis informations for the planning, design and management of the river in the aspect of flood control and environmental conservation, and it is very important to use these informations for the design of stable channel. In this study, dominant discharge was selected, geomorphological and hydraulic characteristics were analyzed using that discharge and also the characteristics of bed materials distribution were analyzed and bed materials-flow resistance relationship was evaluated, for the upstream section of Namgang dam. The dominant discharge was estimated a return period of approximately 1.5 year and stream type were classified Segment 1 and Segment 2 in this stream. Also, the frequency of riffle-pool showed 4.4 because this study area has the characteristics of natural channel that have not channel-crossing structures. In dominant discharge, according to the results that analyzed relationship between $h/d_{50}$ and $V/u_*$ to calculate flow resistance by bed materials, Julian's formula showed to appropriate in channel where is relatively close to natural river and is predominantly consisted of gravel, cobble, boulder and rock in mountain, and it was confirmed that the image processing methodology will be easily applied to the analysis of bed materials distribution in future.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.371-379
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• 2018

In many countries, recycling coal ashes as backfill materials for subsided lands, abandoned mine tunnels, and road pipeline constructions by making low-strength concretes with minimal amounts of cement is frequently considered for massive treatment of coal ashes. This study investigates the variation of heavy metals in the concrete test pieces prepared for the cases of using only Portland cement as binding material, fly ash as a replacement of the cement, sand as aggregates, and disposed ashes in the ash ponds as a replacement of aggregates. Heavy metal contents were measured based on the aqua regia extraction technique following the Korean Standard for Fair Testing of Soil Contamination and the influences of each materials on the total heavy metal contents were also assessed. Results show that the cement has the highest Cu, Pb, and Zn concentrations than any other materials. Therefore, the test pieces show significant concentration decreases for those metals when the cement was replaced by fly ash. Ponded ash shows low concentrations relative to fly ash in most of the parameters but shows higher Cu and Ni, and lower Pb levels than the sand aggregate. In overall, heavy metal levels of the test pieces are regulated by mixing among the used materials. Test pieces prepared during this study always show concentrations much lower than the Worrisome Level of Soil Contamination (Area 1), which was designated by the Soil Environment Conservation Act of Korea.

• Journal of Korean Society of Forest Science
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• v.104 no.1
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• pp.43-49
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• 2015

The production of high quality seedlings is a very important phase in silvicultural systems for successful reforestation or restoration. The purpose of this study was to quantitatively measure both growth performances and nutrient responses of Fraxinus rhynchophylla, Pinus densiflora, and Pinus koraiensis seedlings, which are commercially planted in Korea, according to the different types of soil improvement treatments. We applied soil brought (hereafter 'brought'), subsoil inversion (hereafter 'subsoil'), and mixture of brought soil with soil on nursery bed (hereafter 'mixing') in a permanent national nursery. Silt and clay contents were the highest at the subsoil treatment and organic material, soil nitrogen and phosphorus concentrations were the lowest at the brought treatment. The growth of F. rhynchophylla was the lowest at the subsoil treatment, but there were no significant differences among treatments. There were significant differences in only root nutrient concentrations of F. rhynchophylla among treatments: nitrogen, phosphorus, and potassium concentrations were the lowest at the subsoil or brought treatment. Mixing treatment increased N contents with deduction of N concentrations ('dilution') because of more dry weight increase compared with the amount of N uptake. This study suggested mix of brought soil with soil on a nursery bed in a permanently used nursery can economically be an effective technique to improve soil quality.

• Journal of the Korean Chemical Society
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• v.64 no.5
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• pp.304-317
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• 2020

This study was conducted on four 11^th grade students at a high school in a small town to determine the effectiveness of responsive teaching. The three phases of the responsive teaching method proposed in the previous study were subdivided into six stages; Step 1 is elicitation of students' thoughts related to macroscopic world, Step 2 is drawing of students' early thoughts related to microscopic world, Step 3 is disciplinary connections with ideas of the particle, Step 4 is to clarify the learner's thoughts on the particle by the teacher's involvement, Step 5 is deepening students' thoughts, and Step 6 is expanding ideas. In Step 4, students came to the recognition that the cause of mass was atoms and that the cause of volume was molecules. In Step 5, students led to a shift in thinking that could ignore the volume of the molecules themselves through the properties of protons and neutrons that affect mass from a particle perspective. In the Step 6 of expanding ideas, students explained molecular motion by the concept of material point which ignores the volume of particles. This steps gave students perspectives on the relationship between the mass and volume of particles required by Avogadro's law. The students recognized that some systems could be studied only indirectly because they were too small, too large, too fast, or too slow to observe directly.

• Korean Journal of Agricultural Science
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• v.41 no.3
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• pp.193-203
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• 2014

Natural Monument is a designated cultural property as part of the country. According to Article 2 of the Cultural Properties Protection Act, a national, ethnic and global heritage artificially or naturally formed, with a great historical, artistic, scientific and landscape significance is defined as a cultural heritage. Animals, plants, topography, geology, minerals, caves, biological products and special natural phenomena, having a great of historic, scenic and scientific value, are defined as the monument. According to Article 3 of Cultural Properties Protection Act, the conservation, management and utilization of National Heritage should be kept intact in its original form. So, Natural monuments are managing as retained its original form under the Basic Principles of current law. The highest population of coniferous tree in natural monument plant is ginkgo tree including 22 objects, followed by pines, junipers that order. And in case of broadleaf tree, there are zelkova trees, retusa fringe trees, pagoda trees, cork oaks, silver magnolias and etc. There are many of reported efficacy in available natural monument plants. The efficacy of plant species on pharmaceutical like anti-cancer, anti-diabetic, anti-obesity, antioxidant activity, neuroprotective, improves cholesterol, anti-inflammatory, liver protection and anti-bacterial efficacy, on cosmetics and beauty like the inhibiting formation of skin wrinkles, whitening effect, variety of materials and the efficacy of the proposed utilization of its various papers and etc have been widely reported. Before the Nagoya Protocol enters into force, the future role of the National Research Institute for Cultural Properties Administration of Cultural Heritage should be obtain a legal right to manage the social, cultural and national natural monument with emotional value to the plant genetic resource as a natural monument efficient ways to study and preserve traditional knowledge biological resources by securing a claim to the sovereignty of the material will be ready.

• Korean Journal of Heritage: History & Science
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• v.44 no.3
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• pp.164-177
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• 2011

This study aims to examine the traditional living space to reflect the environment-friendly design methods and principles of reestablishment. To do so, this study carried on a related literature study and field survey. The traditional living space in terms of the environmental friendliness is reflected on site selection and space composition, and utilization of natural energy and natural materials. Focused on the Kwangajeong in Yangdong Village, this study is to identify eco-friendly techniques on the traditional living space. As a result, it shows that Kwangajeong with the side of the southeast in site selection had been considered in aspect of environmental control such as sunshine and solar radiation. Also building construction techniques had been used to minimize the variation of terrain. In aspect of environmental conservation, Kwangajeong had structurally arranged the gate, an inner yard and an inner floor to allow good ventilation. In aspect of space composition, Kwangajeong with the emphasis of scenic view had utilized the methods that attract external landscape through the control of its fences. Environment-friendly techniques and control principles in traditional space had been developed by a long experience through the long periods and the traditional techniques suitable for local climate and local environment have been developed. The technical development of these techniques to resolve the global environmental and energy issues and create a more pleasant living environment of human beings might be critical.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.5-34
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• 2007

Archaeological Heritage is material testimony of national and regional history, and it is one of the tourist's attractions. So it has very important meaning and identical value for a local residents. Public concern on the heritage site elevate higher day by day. They are willing to use it for a multiful purpose, cultural, educational, and even commercial one. But Archaeological Heritage is fragile, and visitors can impact negatively for protection and management of the authenticity on the heritage site. In this research I try to compare legal and administrative measure for the protection, management, and culturalization of Archaeological Heritage in many countries. And I suppose sustainable and practical strategies for keeping integrity of heritage.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.17-24
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• 2020

In this study, series of nonlinear seismic analysis were performed on a reinforced concrete intake tower surrounded by water. To consider the fluid effect around the structure, analysis models were composed using an added mass and CEL approach. At this time, the implicit method was used for the added mass model, and the explicit method was used for the fluid structure interaction model. The input motions were scaled to correspond to 500, 1000, and 2400 years return period of the same artificial earthquake. To estimate the counteractivity of the fluid coupled model, models without fluid effect were constructed and used as a reference. The material models of concrete and reinforcement were selected to consider the nonlinear behavior after yielding, and analysis were performed by ABAQUS. As results, in the acceleration response spectrum of the structure, it was found that the influence of the surrounding fluid reducing the peak frequency and magnitude corresponding to the fundamental frequency of the structure. However, the added mass model did not affect the peak value corresponding to the higher mode. The sectional moments were increased significantly in the case of the added mass model than those of the reference model. Especially, this amplification occurred largely for a small-sized earthquake response in which linear behavior is dominant. In the fluid structure interaction model, the sectional moment with a low frequency component amplifies compared to that of the reference model, but the sectional moment with a high requency component was not amplified. Based in these results, it was evaluated that the counteractivity of the additive mass model was greater than that of the fluid structure interaction model.