• 한국산림과학회지
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• 제83권4호
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• pp.505-511
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• 1994

리기테다 소나무 종자(種子)에 삼투압처리 및 피복(被覆)처리를 하여 균일(均一)한 발아(發芽)와 유묘생육(幼苗生育)을 촉진(促進)하기 위하여 이들 처리(處理) 종자(種子)의 발아(發芽)와 유식물(幼植物) 생육(生育)을 비교(比較) 검토(檢討)하였다. 1. Polyethylene glycol(PEG) 처리농도가 높아질수록 총발아율(TGP)도 높아졌으며 $10^{\circ}C$보다는 $15^{\circ}C$나 $20^{\circ}C$에서 총발아율이 향상되었다. 2. PEG처리기간이 길수록 또한 처리농도가 높을수록 발아속도(GR)가 양호하였으며, 처리농도와 온도간에는 상호 상관관계가 인정되지 않았다. 3. 최대 발아속도(MGR)는 PEG처리기간이 길수록 높았으며, $20^{\circ}C$에서 더욱 뚜렷하게 나타났다. 4. $20^{\circ}C$에서 12일간 PEG 처리시 약 2일 정도의 발아기간(發芽期間) 단축효과가 있었다. 5. PEG 처리는 저수분상태(低水分狀態) 하에서도 발아가 양호하였으며, 피복처리(被覆處理)된 종자는 약해(藥害)로 인한 발아(發芽) 장애현상(障碍現象)이 나타났다. 6. 조파(條播)와 직파(直播)간에는 건물생산량(乾物生產量)에 큰 차이가 있었으며, PEG 처리가 가장 양호한 성적을 보여 주었다. 적당한 토양수분 상태(포장용수량의 약 75%)보다 건조한 토양조건(포장용수량의 약 50%)에서 피복처리효과가 더욱 뚜렷하였다.

• 자연과학논문집
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• 제11권1호
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• pp.131-135
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• 1999

본 연구는 소나무 수피를 상토로 이용하기 위한 연구의 일환으로 보수성을 증진하기 위하여 수행하였다. 연구목적을 달성하기 위하여 건조된 수피를 Wiley mill 또는 hammer mill로 분쇄하여 입도분포를 조절하거나, 분쇄된 물질에 폐암면을 일정 비율로 혼합한 후 토양물리적 특성의 변화를 조사하였다. 분쇄전 수피는 5.6 mm 이상의 직경를 가진 입자의 점유 비율이 86.5%였으나, Wiley mill 또는 hammer mill로 분쇄하므로써 1 mm 이상의 직경을 가진 입자의 점유비율이 감소하고, 1 mm 이하의 입자 비율이 증가하였으며, Wiley mill이 hammer mill 보다 분쇄효과가 높았다. 분쇄에 의해 공극율 및 기상율이 감소하고 용기용수량 및 잔존수분량이 증가하여 보수성이 증가함을 나타내고 있다. Wiley mill로 분쇄된 물질에 50%의 폐암면을 혼합한 경우 공극율 81.1%, 용기용수량 67.7%, 기상율 13.4%, 잔존수분량이 235ml를 갖는 것으로 측정되었는데, 이것은 분쇄와 폐암면의 혼합에 의해 보수성이 증가하였으며, 상업적 생산에 가장 많이 이용되는 피트모쓰+질석 대조구에 비해 보수성이 증가함에도 불구하고 더 좋은 통기성을 보유함을 의미하고 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 터널.암반역학위원회 박사학위 논문집
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• pp.153-204
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• 1998

Prediction of lining loads due to tunnelling is one of the major issues to be addressed in the design of a tunnel. The objective of this study is to investigate rational and realistic design loads on tunnel linings. factors influencing the lining load are summarized and discussed. The instruments for measuring the lining loads are reviewed and discussed because field measurements are often necessary to verify the design methods. Tunnel construction in the City of Edmonton has been very active for storm and sanitary purposes. Since the early 1970's, the city has also been developing an underground Light Rail Transit system. The load measurements obtained from these tunnels are compared with the results from the existing design methods. However, none of the existing methods are totally satisfactory, Therefore, there is some room for improvement in the prediction of lining loads. The convergence-confinement method is reviewed and applied to a case history of a tunnel in Edmonton. The convergence curves are obtained from 2-D finite element analyses using three different material models and theoretical equations. The limitation of the convergence-confinement method is discussed by comparing these curves with the field measurements. Three-dimensional finite element analyses are performed to gain a better understanding of stress and displacement behaviour near the tunnel face. An improved design method is proposed based on the review of existing design methods and the performance of numerical analyses. A specific method or combination of two different methods is suggested for the estimation of lining loads for different conditions of tunnelling. A method to determine the stress reduction factor is described. Typical values of dimensionless load factors nD/H for tunnels in Edmonton are obtained from parametric analyses. Finally, the loads calculated using the proposed method are compared with field measurements collected from various tunnels in terms of soil types and construction methods to verify the method. The proposed method gives a reasonable approximation of the lining loads. The proposed method is recommended as an approximate guideline for the design of tunnels, but the results should be confirmed by field measurements due to the uncertainties of the ground and lining properties and the construction procedures, This is the reason that in-situ monitoring should be an integral part of the design procedure.

• 한국농공학회지
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• 제34권1호
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• pp.41-48
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• 1992

Various soil behaviors usually occurring in the geotechnical problems, such as, cutting and embankments, stability of slope, seepage, consolidations, shearing failures and liquefaction, should be predicted and analyzed in any way. An approach of these predictions may be followed by the development of the constitutive equations as first and subsequently solved by numerical methods. The purpose of this paper is develop the constitutive equation of sands uder monotonic or cyclic loadings. The constitutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parameter by Sekiguchi et al and Pender's theory is derived. And the equation is included a new stress parameter, hardening function, Bauschinger's effects and Pender's theory. The model is later evaluated and confirmed the validity by the test data of Ottawa sand, Banwol sand Hongseong sand. The following conclustions may be drawn: 1. The consititutive equation which is based on elasto-plastic theory, modified anisotropic consolidated stress parpameter by Sekiguchi et al and Pender's theory is derived. The equation in included a new stress parameter, hardening function, Bauschinger's effect and Pender's theory. 2. For Ottawa sand, the result of the constitutive equation shows a better agreement than that of Oka et al. The result of axial strain agrees well with the tested data. However, the result of horizontal strain is little bit off for the cyclic loadings or large stress. It is thought that the deviation may be improved by considering Poisson's ratio and precise measurement of shear modulus. 3. Banwol sand is used for the strain and stress tests with different relative densitites and confining pressures. The predeicted result shows a good agreement with the tested data because the required material parameters were directly measurd and determined form this laboratory. 4. For Hongseong sand, the tests under same amplitude of cyclic deviatoric stress shows a similar result with the tested data in absolute strain. It shows the acute shape of turning point because the sine wave of input is used in the test but the serrated wave in prediction.

• 지질공학
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• 제30권2호
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• pp.131-145
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• 2020

연약지반 상에 도로성토를 시공할 경우 연약지반에는 편재하중이 작용하게 되어 연약지반의 측방유동이나 활동파괴가 종종 발생하게 된다. 본 연구에서는 연약지반에 설치되는 교대말둑기초의 안정성과 말뚝의 거동특성을 파악하는 것이다. 지반의 측방유동으로 인하여 말뚝에 작용하는 수평하중에 대한 기존 연구자들의 연구내용을 파악하고 유한요소해석을 수행하여 교대말뚝기초의 거동특성과 보강효과를 확인하여 측방유동을 받는 교대말뚝기초의 거동을 연구하였다. 압밀도 분석 결과, 압밀 단계에 따라 연약지반 강도증가율에 의해 연약지반의 강도정수인 점착력은 약 1.1~1.8배 증가하였다. 측방유동 검토 결과, 허용수평변위 기준은 3.8 cm를 사용하는 것이 경제적으로나 시공적인 면에서 타당한 것으로 판단되나, 구조물의 중요도 및 지반의 불확실성 등을 고려하여 시공 시 계측을 실시하고 그에 따른 측방유동에 대한 철저한 안전관리가 이루어져야 할 것으로 판단된다.

• 한국염색가공학회지
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• 제11권6호
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• pp.24-35
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• 1999

This study was carried out to investigate the changes of surface characteristics of polyester fabrics on the deposition and the removal of oily soils from polyester fabrics in detergency, The relations between the removal of soil and the changes of surface properties of polyester fabrics treated with water- and oil-repellent agents were discussed before and after various wash cycles. Two kinds of fluoropolymers were selected as water-and oil-repellent finishing agents. The effects of water- and oil-repellent finishes were determined by the water repellency and oil repellency. The surface properties of untreated and treated polyester fabrics were evaluated with respect to contact angle and wicking time. The treatment of polyester fabrics with fluoropolymers improved efficiently water repellency, oil repellency, contact angle and wicking time. But those properties were greatly decreased after 3 times of wash cycles in detergency The deposition of oily soils on the untreated fabrics was drastically increased with increasing of wash cycles. The deposition and the removal of oily soils from fabrics treated with fluoropolymer having hydrophobic components were very low after various wash cycles. The deposition and the removal of oily soils on the fabrics treated with fluoropolymer having hydrophilic components were high comparatively after various wash cycles. Even though the surface properties of treated fabrics were greatly decreased with the increasing of wash cycles, the remains of oily soils on the fabrics were lower than those of untreated fabrics in various wash cycles. But the remains of soils were drastically increased after 10 times of wash cycles in any cases.

• 한국환경과학회지
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• 제32권1호
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• pp.57-65
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• 2023

The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.

• 대한토목학회논문집
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• 제11권1호
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• pp.167-176
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• 1991

본 연구에서는 기존의 구성 모델인 hyperbolic모델과 Cam-clay모델을 적용하는 유한요소해석 프로그램을 개발하였다. hyperbolic모델에서는, 전단중의 체적 변형을 고려하는 새로운 모델을 제시하였으며, 또한 기초 아래 지반의 밀도 증가로 인한 매개 변수값의 변화를 고려하는 새로운 개념을 제안하고자 했다. 이와 더불어 보다 타당하다고 생각되는 계산 알고리즘을 제안하였다. 또한 Cam-clay모델을, 연구 사례가 많지 않은 모래질 흙에 적용함으로써 모래질 흙의 거동을 한계 상태 개념의 관점에서 분석해 보고자 하였다. 이를 위해 일반적인 압밀 배수 삼축 압축 시험과 모형 기초 재하 실험을 실시하였다. 그 결과, 본 논문에서 제안한 수정 hyperbolic모델을 사용함으로써 기존 모델보다, 기초에 작용하는 하중의 크기가 극한 지지력의 50%일때, 기초의 침하량 예측에 있어서 약 60% 정도, 결과의 향상을 기할 수 있었다. Cam-clay모델을 모래에 적용하는 경우에는 과압밀 효과를 고려할 수 있는 모델 및 변형률 연화를 고려할 수 있는 계산 알고리즘이 필요하다고 생각된다. 초기 포아송비의 크기는 Cam-clay모델의 경우 결과에 큰 영향을 미치지 않았으나, hyperbolic모델의 경우 결과에 큰 영향을 미치므로, 초기값의 선정에 신중하여야 함을 알 수 있다.

• 한국동물위생학회지
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• 제29권2호
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• pp.129-154
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• 2006

Last year, over 800 Australian live cattle were imported, underwent quarantine procedure for one month in the port of Incheon and Busan and distributed to general farm house holds in Gyeongju city, Gyeongbuk province, and Gimhae city, Namhae county, Gyeongnam province. But Hanwoo association took violent actions to prevent from entering the country for fear that the imported live cattle would destroy the 'Hanwoo industry', and in turn leads to the collapse of the industry. In Australia, national animal protection body 'Animals Australia' investigated the level of cruelty involved in this trade and made a report 'The death file'. Australia governments drive to expand Its market for 'live animal exports' and it has resulted in a corresponding increase In casualties associated with the long-haul overseas trade in live livestock animals over the past years. After the stress of transportation, all the surviving cattle and sheep face death on foreign soil, many into countries which have no animal welfare laws or, at best, inadequate laws. They will usually be killed without pre-stunning and often even without adequate restraint facilities. The result is inherent and persistent suffering. West Australian(WA) Police acting on behalf of the West Australian Government and the Office of the WA State Solicitor have laid animal cruelty charges against a leading WA live export company for breaching the WA Animal Welfare Act. With the aim of eventually substituting it for the live sheep trade, the Senate Select Committee on Animal Welfare (SCCAW) recommended that the Federal Government 'promote and encourage the expansion of the refrigerated sheep meat trade to the Middle East and other countries'. Animal welfare standards have been improved time after time, there is another incident, another public outcry, another inquiry and more assurances.

• 한국지반환경공학회 논문집
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• 제9권7호
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• pp.13-23
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• 2008

본 연구에서는 모래다짐말뚝으로 개량된 점성토 지반에 고성토시 발생될 수 있는 측방유동과 교대의 안정성을 파악하기 위하여 원심모형실험과 수치해석을 수행하였다. 원심모형실험과 수치해석은 교대 배면구간을 EPS로 성토한 경우(Case 1)와 토사로 성토한 경우(Case 2)에 대하여 수행하였으며, 모형실험시 교대와 성토체에 potentiometer를 설치하여 교대상부의 수직변위와 수평변위 및 성토체의 수직변위를 측정하였다. 원심모형실험결과 Case 1에서 교대의 수평변위는 1.4cm 정도로 해석결과와 거의 일치하며, 허용기준을 만족하는 것으로 나타났다. 반면, Case 2에서 교대의 수평변위는 12cm 정도로 해석결과에 비해 18% 정도 크게 평가되었으며, 허용기준을 초과하는 것으로 나타났다. 해석결과 Case 1에서 말뚝의 최대수평변위는 1.26cm로 허용 수평변위 기준(1.5cm)을 만족하는 것으로 나타난 반면, Case 2에서 말뚝의 최대 수평변위는 1.005m로 허용기준을 크게 초과하는 것으로 나타났다.