• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.137-137
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• 2001

서울시는 인구과밀, 크고 낮은 많은 산들, 높은 차량증가율과 수도권의 공업과 인구집중화 등의 이유로 그간의 많은 노력과 행정력의 집중에도 불구하고 질소산화물과 오존농도는 오히려 증가패턴을 나타내고 있다. 2002년도는 세계적인 월드컵대회가 한일공동으로 개최될 예정이고, 개회식이 개최될 서울 마포구 상암동 일대는 월드컵경기장 공사와 주변정리 작업이 한창이다. 직선거리로 400-500m의 풍상측(주풍방향 서북풍)에는 세계에서 가장 큰 규모의 하나인 비위생적 쓰레기 매립지가 위치하고 있고 이는 15년간 9천2백만㎥의 쓰레기가 묻혔으며 매립이 중단된지 9년이 되었다. (중략)

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.34-35
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• 2018

낙동강 하류역은 최근의 퇴적우세 지형변화와 더불어, 기후변화에 따른 태풍강도 강화 등으로 인한 해일고 증가가 우려된다. 따라서, 과거 태풍자료를 수집 분석한 후 연구지역에 가장 큰 영향을 미친 태풍을 모델 태풍으로 선정하여 낙동강 하류역에 위치한 주요지점별 폭풍해일고 변화를 파악하였다. 실험결과, 최대 폭풍해일고는 태풍 매미 내습시에 나타났으며, 하단 매립지 전면에서 1.1~1.5m, 명지주거단지 전면에서 1.2~1.3m, 녹산국가산업단지 전면에서 1.3~1.5m로 하단 매립지 전면이 가장 크게 나타났다. 향후, 과거 지형변화를 고려한 폭풍해일고 검토를 통하여 최근의 급격한 지형변화로 인한 영향을 파악한 대비를 해야 할 것으로 사료된다.

• Journal of the Korean Society for Railway
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• v.14 no.3
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• pp.240-247
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• 2011

Finite element analysis was undertaken to investigate the effect of freezing force of water unexpectedly penetrated into inserts used in railway sleeper on pullout capacity of anchor bolts for fixing base-plate onto concrete sleeper. Based on the in-situ investigation and measurement of geometry of railway sleeper and rail-fastener, the railway sleeper was modeled by 3D solid elements. Nonlinear and fracture properties for the finite element model were assumed according to CEB-FIP 1990 model code. And the pullout maximum load of anchor bolt obtained from the model developed was compared with experimental pullout maximum load presented by KRRI for verification of the model. Using this model, the effect of position of anchor bolt, amount of fastening force applied to the anchor bolt, and compressive strength of concrete on pull-out capacity of anchor bolts installed in railway sleeper was investigated. As a result, it is found that concrete railway sleepers could be damaged by the pressure due to freezing of water penetrated into inserts. And the pullout capacity of anchor bolt close to center of railway is slightly greater than that of the others.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.575-586
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• 2004

This paper presents an experimental study on the flexural capacity of an encased(slim-floor) composite beam, which is a wider plate under bottom flange of H-beam with web openings. Five simple full-scale bending tests were conducted on the encased(slim-floor) composite beams at varying steel beam heights (250mm and 300mm), positions of web openings, and loading conditions. The test results revealed that the web-open encased composite beam had sufficient composite action, without any additional shear connection devices, because of the inherent shear-bond effects between the steel beam and the concrete, and a stable structural performance without web-opening reinforcements.

• Geotechnical Engineering
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• v.13 no.1
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• pp.59-74
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• 1997

This paper presents the results of the geotechnical investigation and settlement analysis of a finished waste landfill to find the possibility of the site as a construction area. Also, the variations of the strength of the municipal waste after mixing with the several types of the particulate grouts are investigated. The materials of the grouts used in the experiment are Quick Lime, Portland Cement, Slag Cement and Geocrete Cement. The results of the geotechnical investigation show that the maximum dry unit weight of the waste becomes lower and optimum moisture content higher as the age of the disposed waste is younger and the organic content is higher. The thickness of the predicted differential settlements of the waste fill has large difference from location to location and the unconfined compression strength of the grout mixed waste from the experiment was higher in the order of Geocrete Cement, Slag Cement, Portland Cement and Quick Lime.

• Journal of the Korean Geosynthetics Society
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• v.5 no.2
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• pp.17-22
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• 2006

This paper presents preliminary field investigations on the electrokinetic (EK) remediation coupled with permeable reactive barrier (PRB) system. unregulated and old-fashioned landfills are one of the primary contributors to various contaminated soil problems. In-situ EK remediation technology has been successfully applied to the environs of unregulated landfill site, located in Kyeong-Ki province, Korea. Atomizing slag was adopted as a PRB reactive material for the remediation of groundwater contaminated with inorganic and/or organic substances. From the preliminary investigations, the coupled technology of EK with PRB system would be effecitve to remeidate contaminated grounds without the extraction of pollutants from subsurface due to the reactions between the reactive materials and contaminants.

• Korean Journal of Weed Science
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• v.17 no.3
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• pp.269-280
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• 1997

Collated data from the 1995-1996 field surveys of weed seeds buried in the plough layer of peat soil in Selangor district were analysed to assess species-dominance and spatial pattern of distribution of weed seeds based on selected quantitative indices and index of dispersion. Forty five species within 14 families were recorded of which 24 were broadleaves, 12 grasses and 9 sedges. They comprised ca. 53.2, 31.2 and 15.6%, respectively based on total population counts. Total seed population was ca. $8.14{\times}10^7$ seeds/ha within the fast 25cm soil depth. Wide variabilities in population counts were registered among species ranging from < $7.0{\times}10^4$ seeds/ha for Amaranthus gracilis to ca. $5.64{\times}10^6$ seeds/ha for Heteropogon contortus. Seeds of Cleome rutidesperma was the most abundant(ca. $2.347{\times}10^7$ seeds/ha). Difference in seed population counts may be attributed to inherent variation in fecundity, population fluxes, their spatial distribution patterns and the agronomic practices prevailing in the areas of survey. The profile distribution of soil seed banks was skewed within the first 0 - 10cm depth, comprising ca. 69% of the total seed counts. Seed counts in the 10 - 15, 15 - 20 and 20 - 25cm soil profiles were in the order of 17.9, 8.6 and 4.0% of the total populations, respectively. Weed seeds of all species displayed different degree of aggregated pattern of distribution with variance-to-mean ratios of > 1 and Lloyd's mean crowding($m^*$) values from 1.244 for Cyperus iria, Phyllanthus debilis, Phyllanthus urinaria, Scirpus grosses and urinaria lagopodiodes to 9607.7 for Cleome rutidosperma. Lloyd's patch indices(Ip) ranging from 5.1 for Aeschynomene indica to 188.5 for Bracharia reptans were registered. Differences in the VMR, $m^*$ and Ip values among species suggested inter-alia inherent variabilities in their disposal capacity from seed source and different agronomic practices prevailing in the areas surveyed.

• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.153-161
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• 2002

In order t determine blasting sites for the crustal refraction studies in the korean peninsula, seismic refraction profiling was conducted at two sites in the reclaimed land of Seosan. At a quarry for construction material and another site on a rice field 2km east of the quarry, 24 channel refraction profiling of 46m was conducted at a geophone spacing of 2m. Seismic velocity profiles obtained through tomographic invesion reveal that the quarry is regarded as an ideal place for blasting based on the observation that fresh basements with seismic velocities of 3,900 m/s or greater locate approximately 6m deep. On the contrary, under the reclaimed rice field, the basements are weathered more, of slower velocities, and buried deeper than quarry, indicating not an ideal location for detonating seismic explosives of large amounts.

• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.

• Journal of the Korea Institute of Building Construction
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• v.23 no.5
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• pp.519-526
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• 2023

This research endeavors to explore the nuances in apparent resistivity readings in concrete specimens due to the proximity of embedded reinforcement. To systematically gauge this, concrete samples incorporating singular and paired rebars were meticulously crafted. These rebars were strategically positioned at intervals of 0.03m, 0.04m, and 0.05m from each specimen's midpoint. Subsequent resistivity assessments were conducted at 0.01m increments up to the predetermined rebar location for each sample. A consistent observation was the nadir in apparent resistivity manifesting at the rebar's epicenter. Notably, dual-rebar configurations registered lower resistivity values at this central juncture compared to their single-rebar counterparts. This metric underscores the palpable impact of surrounding reinforcement on resistivity readings. Further, as the spatial separation between rebars increased, the distinctness in their locational identification via resistivity became increasingly pronounced.