• Resources Recycling
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• v.8 no.4
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• pp.11-19
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• 1999

Fly ash generated from (he pulverized coal power plant have caused the serious ocean pollution due to the disposal in the ash pond, the life reduction of a power plant and the waste of re-utilizable resource The research to reuse the unburned carbon and mineral composing of the ash has been progressed. In this study. the physical and chemical characteristics of high grade ash and unburned carbon particles obtained from countercurrent column flotation are investigated. The cleaned ash of the less 0,5% loss on Ignition(LOI) in carbon content is a spherical sphere and 39.8${\mu}m$ in size of MMD(Mass Median Diameter). 2.22 $m^2/g$ of specific area. The morphology of high LOI carbon particles is a amorphousness, 76.6 ${\mu}m$ of particle size and 15.2 $m^2/g$ of specific The high grade cleaned ash and the high LOI ash have some difference in the light of physical. chemical and morphological characteristics

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.122-140
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• 2001

We have applied the geophysical survey, mainly electric and electromagnetic (EM) methods, to a test site contaminated by hydrocarbon waste disposal and local spill. The multi-frequency, moving source & receiver EM survey along with ground penetrating radar (GPR) showed a fairly good performance in detection of buried metal pipes and objects. Magnetic survey measuring vertical and horizontal gradients were so sensitive to the small metallic objects spread over the surface that it's hard to discriminate the buried pipe. We chose electrical resistivity, EM and GPR survey to examine the soil contamination. Depth slices of resistivity distribution as the results of the inversion of resistivity and EM data coincided each other and closely matched the contaminated area determined by chemical analysis of the soil samples. GPR images did not show the reflection events related with contamination plume since there are no distinct spill in this site. We inferred the contamination using the penetration depth of the GPR energy, which could be used as auxiliary information to the resistivity and EM results. We summarized the applicability of each survey methods based on this results and proposed a desirable survey scheme for the determination of hydrocarbon contaminated site.

• Journal of Radiation Protection and Research
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• v.16 no.2
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• pp.27-39
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• 1991

The diffusion of Sr-85, Cs-137, Co-60 and Am-241 in compacted domestic bentonite was studied, using a diffusion cell unit in which diffusion took place axially from the center of cylindrical bentonite sample body. The effects of compaction density and heat-treated bentonite on diffusion were analysed. And the diffusion mechanism of radionuclide was also analysed by evaluating the measured diffusivity of anion Cl-36. The apparent diffusivities obtained for Sr-85, Cs-137, Co-60 and Am-241 were $l.07{\times}10^{-11},\;6.705{\times}10^{-13},\;l.226{\times}10^{-13}\;and\; l.310{\times}10^{-14}m^2/sec$, respectively. When the as-pressed density of bentonite increased from $1.8\;to\;2.0g/cm^3$, the apparent diffusivity of Cs-137 decreased by quarter. In the case of bentonite heat-treated to $150^{\circ}C$, no significant change in diffusivity was observed, which showed the possibility that the domestic bentonite could be used as a chemical barrier to retard the radionuclide migration at below $150^{\circ}C$. From the calculated pore and surface diffusivity, the surface diffusion due to the concentration gradient of radionuclide sorbed on the solid phase was found to dominate greatly in total transport process.

• Journal of the Korean association of regional geographers
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• v.15 no.1
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• pp.1-15
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• 2009

This study aims to provide preliminary data needed for establishing policies on the environment and disasters of Goryeong county. The main results are as follows. First, the present master plan of the region does not reflect local socio-economic and environmental conditions and the local people's opinion. Second, The air conditions of Gyeongbuk province and Goryeong county are within the permitted limit of air pollution of Korea. Third, the analysis of water pollution index in Nakdong river system shows improvement of water quality in both Andong and Goryeong. Fourth, the conditions of waste collection and disposal are improved in both Gyeongbuk province and Goryeong county. Fifth, in case of environmental pollutant emitting facilities of Gyeongbuk province, the proportion of 1st to 4th grade(relatively much more environmental pollutant emitting quantity than 5th grade) tends to be increasing. Sixth, environmental pollutant emitting facilities of Goryeong county are remarkably increasing in Dasan, Gaegin, Ssangrim, involving industrial complex. Finally, in case of disasters, it is relatively stable in Yecheon, Gumi, Uiseong, Yeongju and Cheongdo, while relatively unstable in Seongju, Gunwi, Yeongcheon, Chilgok, Mungyeong, Bonghwa and Goryeong.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1264-1272
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• 2015

This study was performed to compare the perceived importance and performance frequency of the core nursing skills between general and special department. Subjects were 182 nurses who work on the hospital. Data was collected using items made by Korean accreditation board of nursing education and analyzed by frequency, mean and t-test. There were differences of importance and frequencies about nursing core skill between general and special wards. Core nursing skills of general wards were higher importance on intradermal injection(p=.011), transfusion(p=.028), simple catheterization(p=.047), cleansing enema(p=<.001), preoperative and postoperative care(p=.035), management administration(p=.027) and oxygenation with cannular(p=.002) than special wards. Actual performance frequency core nursing skills of general wards were higher similar on transfusion(p=.002), intermittent tube feeding(p=.032), simple catheterization(p=<.001), cleansing enema(p=<.001), preoperative care(p=.001), postoperative care(p=<.001), management administration(p=.001), protection equipment for quarantine room and waste disposal(p=.021), oxygenation with cannular(p=<.001) than special wards. It is needed to develop efficient and sequential program to learning the nursing core skills for nursing students.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.3
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• pp.239-248
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• 2020

Exact rock classification helps suitable support patterns to be installed. Face mapping is usually conducted to classify the rock mass using RMR (Rock Mass Ration) or Q values. There have been several attempts to predict the grade of rock mass using mechanical data of jumbo drills or probe drills and photographs of excavation surfaces by using deep learning. However, they took long time, or had a limitation that it is impossible to grasp the rock grade in ahead of the tunnel surface. In this study, a method to predict the Q value ahead of excavation surface is developed using recurrent neural network (RNN) technique and it is compared with the Q values from face mapping for verification. Among Q values from over 4,600 tunnel faces, 70% of data was used for learning, and the rests were used for verification. Repeated learnings were performed in different number of learning and number of previous excavation surfaces utilized for learning. The coincidence between the predicted and actual Q values was compared with the root mean square error (RMSE). RMSE value from 600 times repeated learning with 2 prior excavation faces gives a lowest values. The results from this study can vary with the input data sets, the results can help to understand how the past ground conditions affect the future ground conditions and to predict the Q value ahead of the tunnel excavation face.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.599-615
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• 2022

In order to excavate underground tunnel most safely such as Han river, the slurry shield TBM method is applied to cope with face of high water pressure for many metro projects. In downtown subway project most of excavated soil is discharged externally whereas in road construction excavated soil is used as filling materials so it becomes important factor for success of the project. After excavated soil, weathered rock and soft rock are discharged with bentonite through discharge pipe to slurry treatment plant then those soils are separated in separation plant according to those size. Fine grained soil has been discarded together with filter cake but it is not toxic and can be mixed with coarse aggregate in proper ratio so this study is performed to find use of qualified filling material to meet quality standard. Therefore, in this study, legal standards and quality standards for the utilization of excavated soil of the slurry shield TBM method were examined and test was conducted to derive recycling way for filter cake and aggregate. And a plan for using it as a filling material for road construction was derived. Because bentonite is a clay composed of montmorillonite, and the excavated soil in the tunnel is also non-toxic, disposal of this material can waste social cost so it is expected to be helpful in the underground space development project that carries out the TBM project by recycling it as a valuable resource.

• Journal of Mushroom
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• v.17 no.3
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• pp.132-135
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• 2019

This study aimed to develop a new method of Lentinula edodes cultivation to reduce labor and waste disposal. To identify the optimum container for L. edodes cultivation, box, bottle, and bag containers were assessed for their effects on the cultural characteristics and mushroom yield. Among the three approaches, box-cultivation with 7 kg of substrate had the shortest browning period (42 days) and resulted in the highest mushroom yield (1,253 g). Contrastingly, bottle-cultivation was unsuitable for cultivation due to low production of the fruiting bodies and poor quality. Further studies on the box-cultivation approach will be required for commercial applications of L. edodes.

• Tunnel and Underground Space
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• v.31 no.4
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• pp.243-269
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• 2021

Since the early 2010s, the social importance of research and practical projects targeting deep geological disposal of high-level nuclear waste, underground CO₂ storage and characterization of deep subsurface by borehole investigation has been increasing. In this regard, there is also a significant increase in the need for in situ test technology to obtain quantitative and reliable information on the hydraulic characteristics of deep rock mass. Through years of research and development, we have independently set up Deep borehole Hydraulic Test System (DHTS) based on the key apparatuses designed and made with our own technology. Using this system, high precision constant pressure injection tests were successfully completed at the two 1 km boreholes located in Mesozoic granite and sedimentary rock regions, Gyeongju. During the field tests, it was possible to measure very low flow rate below 0.01 l/min with micro flow rate injection/control module. In this paper, the major characteristics of DHTS are introduced and also some results obtained from the high precision field tests under the deep and low permeable rock mass environment are briefly discussed.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.1-17
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• 2021

It is important to evaluate the fracture network in a rock volume because fractures control the ground conditions and fluid flow characteristics. Therefore, various attempts have been made to quantify fracture networks to better understand ground and flow conditions. The use of fracture density alone (a quantitative parameter based on geometric analysis) does not fully explain the evolution of fracture networks, or quantify the spatial relationship (e.g. connectivity) of fractures in a rock mass. Therefore, the need for fracture network characterization based on topological analysis has recently emerged. In Korea however, the topological analysis of fracture networks within a rock mass has rarely been studied. As such, the definition of the topological analysis of fracture networks and the graph theory related to the topological analysis are briefly summarized in this study. We also introduce an application method for these analyses to fracture characterization. If the topological method is used for the analysis of fracture networks, it can also be adopted to analyze fluid flow characteristics of groundwater, characterize petroleum reservoirs, and analyze the evolution of a fracture network. In addition, topological analysis can be useful for site selection of major facilities such as nuclear waste disposal sites because it can be used to evaluate the stability of the potential sites.