• Geomechanics and Engineering
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• v.15 no.3
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• pp.889-898
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• 2018

Backfilling of mine stopes with waste rocks or tailings is commonly done to enhance ground stability. It is also an alternative for mining wastes disposal. A successful application of underground backfilling requires an accurate evaluation of the stress distribution in stopes. Over the years, various analytical solutions have been proposed to assess these stresses. Most of them were based on the arching theory, considering uniform stresses across horizontal layer elements. The vertical and horizontal stresses in vertical stopes are principal stresses only along the vertical center line, but not close to the walls where there is rotation of the principal stresses. A few solutions use arc layer elements that follow the iso-contours of the minor principal stresses, based on numerical solutions. In this paper, a modified analytical solution is developed for the stresses in vertical backfilled stopes, considering a circular arc distribution. The proposed solution is calibrated with a few numerical modeling results and then validated by additional numerical simulations under different conditions.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.335-339
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• 2003

The estimation of seawater intrusion into deep aquifers has been becoming an important subject in terms of site characterization for geological disposal of radioactive waste. Conventional direct-current resistivity methods have been used for ground water explorations and recently have been applied to environmental problems. However, electromagnetic methods are more practical and useful for such a deep investigation. We consider audio-frequency magnetotelluric (AMT) and surface-to-borehole electromagnetic (EM) tomography methods as promising tools for the investigation of deep aquifer. These methods were tested in the Hasunuma area, Chiba Prefecture, Japan. Although the study area is in an urban area, high-quality AMT data were acquired, which was mainly accomplished by night-time data recording and remote-reference data processing. One-dimensional inversion results of the AMT data revealed two extremely conductive zones, which is consistent with the electrical conductivity profile of pore water in core samples. It can be interpreted as the seawater intrusions into both zones. However, the chemical analysis of the groundwater sampled in the deep zone suggests that this groundwater must be fossil seawater that had been confined during sedimentation processes. In addition, the permeability coefficient of the deep layer is very low. Thus the deep conductive zone corresponds to the fossil seawater regarded as being difficult to flow.

• Journal of Environmental Impact Assessment
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• v.21 no.6
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• pp.927-939
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• 2012

Cool roofs are currently being emerged as one of important mechanism to save energy in relation to the building. Although green roof has already gained nation-wide recognition as a typical method of energy saving in the roof, this approach did not provide a realistic evidence that is economically feasible in terms of installation cost. This research is primarily intended to compare installation cost between the two techniques. This research proposes a comparative evaluation framework in a more objective and quantitative way for an installation cost between the two techniques. Kyungpook National University (KNU) was selected as a survey objective and an exhaustive and realistic comparison of installation cost between the two techniques was conducted, based on Life Cycle Cost analysis (initial investment cost, maintenance cost, dismantling and waste disposal expense). It was possible to identify that installation cost of cool roofs is 4.7 times cheaper than that of green roof. Also present value based on probabilistic approach was identified as 0.25 (4.95) higher than the installation cost on the assumption of constant price and interest. It is expected that much more installation cost for the large scale green roof will be required since small-size green roof selected as a survey objective in this study could be operated under less initial installation and maintenance condition.

• Korean Journal of Organic Agriculture
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• v.21 no.1
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• pp.1-18
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• 2013

Animal and crop production systems were integrated on a single farm. This integrated farming system recycled nutrients on the farm. The separation of animal and crop production with the introduction of cheap commercial fertilizers, farms were not used land-applied manure. The on-line manure matching is one of the emerging business in the achievement of recycling and resource recovery. The manure matching actively promotes the reuse and recycling of by-products and manure. This study constructs to manure matching information system to solve the exchange problems between herders and croppers. Manure matching web sites designed. This paper introduces a web-based animal manure matching system. A manure matching service, part of the manure transport, links farmers who produce excess manure with farmers who can use the manure. Farmers registered with the service have requested manure. The manure matching service supports the transport project by linking farmers with excess manure with those farmers who can utilize the manure safely as a nutrient source. The goal of the service is to protect water quality by fostering efficient land application. Benefits to those who use the manure network include reduced disposal costs, lower purchase costs and recycling of manure. The manure matching is based on the principle that 'one persons waste is another person's fertilizer.' It provides a free online matchmaking service for environmentally safe manure recycling management system.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.548-557
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• 2015

This study investigated environmental assessments of leachate containing formaldehyde from medium density fiberboard (MDF) disposed in laboratory-scale simulated landfills. Environmental impact assessment of leachate was conducted by measuring formaldehyde, toxicity, biochemical oxygen demand (BOD), chemical oxygen demand (COD), bacterial enumeration, and pH. Amount of formaldehyde in leachate from MDF in soil decreased to the level of soil only treatment by 28 days, and toxicity decreased as the amount of formaldehyde decreased. BOD and COD levels in leachate from the treatments containing MDF exceeded permissible discharge levels of BOD or COD throughout the experimental period. The pH levels of all treatment were within permissible discharge range except on day 0. Fewer bacteria were observed in leachate from MDF in soil treatment than other treatments (MDF only, cured UF resin in soil, and soil only). Consequently, the leachate from disposal of MDF in soil detrimentally affect on environment. However, soil buffered formaldehyde leaching and pH on leachate in this study. Waste MDF may be required the pre-water soaking treatment for leaching formaldehyde to reclaim on land.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.103-105
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• 2005

The importance of protecting people from harsh weather conditions cannot be over-emphasized and the way to. do so should be sought vigorously. The most well known and widely used weather protection fabric in the current industry is $Gor-Tex.^1$ However, the Gore-Tex membrane cannot be attached to cotton or other natural fibers so it's use is not suitable for clothing such as underwear. If the exterior of cotton fabric can be made to be hydrophobic without sacrificing the comfort and breathability, the result will be a cotton fabric with the weather protection capability equivalent to Gore-Tex as well as the ability to provide the best wear comfort. However, this should be done without using toxic and expensive gases to be environmentally friendly and cost effective. Therefore, our approach for hydrophobic treatments of fabric and metal surfaces is to utilize a plasma-based technique. In general, plasma processes do not produce chemical wastes or waste disposal problems and they are fully automated.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.118-128
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• 1984

The analysis of radiological protection at Kori Nuclear Unit #1, which started commercial operation on April 29, 1978, has been carried out in three areas, namely, radiation exposure, radioactive waste disposal and environmental management. The analysis results for radiation exposure and radioactive effluent releases appear to increase gradually with plant operating years. On the other hand, the apex of radiation exposure and radioactive effluent releases was in 1983 and 1982 respectively and then decreased or stabilized. Also, the operation environmental radioactivity seems to be no higher than preoperation environmental radioactivity.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.4
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• pp.1-7
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• 2016

This paper presents a design method for the horizontal straight ground heat exchanger (GHE) based on the Kavanaugh design method. In order to examine suitability of the suggested design method, a horizontal line type GHE was installed in a steel box of which the size was $5m{\times}1m{\times}1m$ filled with dried Joomunjin standard, and a thermal response test (TRT) was conducted for 21 hours. A numerical analysis was performed for a simulation of a peak month operation and for its verification by finite element method (FEM). According to the simulation results, it was concluded that the suggested design method for a horizontal straight GHE is reliable for the estimation of a design length.

• Tunnel and Underground Space
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• v.13 no.2
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• pp.138-152
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• 2003

Three-dimensional computer modeling using FLAC3D had been carried out fur evaluating the thermal-mechanical stability of a high-level radioactive waste repository excavated in several hundred deep location. For effective modeling, a FISH program was made and the geological conditions and rock properties achieved from the drilling sites in Kosung and Yusung areas were used. Sensitivity analysis fer the stresses and temperatures from the modeling designed utilizing fractional factorial design was carried out. From the sensitivity analysis, the important design parameters and their interactions could be determined. From this study, it was found that deposition hole spacing is the most important parameter on the thermal and mechanical stability. The second and third most important parameters were disposal tunnel and buffer thickness.

• Tunnel and Underground Space
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• v.25 no.6
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• pp.556-567
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• 2015

The evaluation of THM coupling behavior in deep underground repository condition is essential for the long term safety and stability assessment of high-level radioactive waste repository. In order to develop reliable THM analysis techniques effectively, an international cooperation project, DECOVALEX, is carried out. In DECOVALEX-2015 Task B2, the in situ THM experiment planned to be conducted by JAEA was modeled by the research teams from the participating countries. In this study, a THM coupling technique combining TOUGH2 and FLAC was developed and applied to 1 dimensional THM modeling, in which rock, buffer, and heater are considered. The results were compared with those from other research teams.