• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.1-7
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• 2018

This study examined the effect of binder-to-soil ratio(B/S) and water-to-binder ratio(W/B) on the flow and compressive strength development of soil concrete using high-volume supplementary cementitious materials. As a partial replacement of ordinary portland cement, 10% by-pass dust, 40% ground granulated blast-furnace slag, and 25% circulating fluidized bed combustion fly ash were determined in the preliminary tests. Using the low-cement binder incorporated with clay soil or sandy soil, a total of 18 soil concrete mixtures was prepared. The flow of the soil concrete tended to increase with the increase in W/B and B/S, regardless of the type of soils. The compressive strength was commonly higher in sandy soil concrete than in clay soil concrete with the same mixture condition. Considering the high-workability and compressive strength development, it could be recommended for low-cement soil concrete to be mixed under the following condition: B/S of 0.35 and W/B of 175%.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1078-1086
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• 1996

The peroxo-polytungstic acid was formed by the direct reaction of tungsten powder with the hydrogen peroxide solution. Peroxo-polytungstic powder were prepared by rotary evaporator using the fabricated on to ITO coated glass as substrate by dip-coating method using $2g/10mL(W-IPA/H_2O)$ sol solution. A substrate was dipped into the sol solution and after a meniscus had settled, the substrate was withdrawn at a constant rate of the 3mm/sec. Thicker layer could be built up by repeated dipping/post-treatment 15 times cycles. The layers dried at the temperature of $65{\sim}70^{\circ}C$ during the withdrawn process, and then tungsten oxides thin film was formed by final heating treatment at the temperature of $230{\sim}240^{\circ}C$ for 30min. A linear rotation between the thickness of thin film and the number of dipping/post-treatment cycles for tungsten oxides thin films made by dip-coating was found. The thickness of thin film had $60{\AA}$ after one dipping. From the patterns of XRD, the structure of tungsten oxides thin film identified as amorphous one and from the photographs of SEM, the defects and the moderate cracks were observed on the tungsten oxides thin film, but the homogeneous surface of thin films were mostly appeared. The electrochemical characteristic of the $ITO/WO_3$ thin film electrode were confirmed by the cyclic voltammetry and the cathodic Tafel polaization method. The coloring bleaching processes were clearly repeated up to several hundreds cycles by multiple cyclic voltammetry, but the dissolved phenomenon of thin film revealed in $H_2SO_4$ solution was observed due to the decrease of the current densities. The diffusion coefficient was calculated from irreversible Randles-Sevick equation from the data obtained by the cyclic voltammetry with various scan rates.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.1
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• pp.67-75
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• 2013

Recently, the interest is increasing about the exposed concrete, accordingly, exposed concrete is expanding the use. However, concrete structures is difficult to apply the general concrete for exposed concrete, due to complex section and compact reinforcement, increasingly. Therefore, in this paper, for application of high fluidity concrete as exposed concrete, exposed high fluidity concrete using fly ash and lime stone powder was manufactured and observed quality property(fluidity properties, mechanical properties and Surface Properties) of exposed high fluidity concrete. The experiments are based on the OPC and LSP10, was evaluated Impact on the quality of concrete according to mixing ratio of FA(0, 10, 15 and 20). As a result, fluidity properties, mechanical properties and Surface Properties of exposed high fluidity concrete were satisfied to requirement conditions, fluidity and surface finishability was improved depending on mix of fly ash and limestone powder. Through this, we utilize of basic research data for development of high fluidity concrete for exposed concrete.

• Journal of the Korea Convergence Society
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• v.8 no.2
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• pp.291-297
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• 2017

This study was aimed to secure the basis for developing the hangbang-tea may help promote healthy blood vessels by natural herbal ingredients formulated in accordance with the basic principles of oriental medicinal theory. We investigated the vessels contracted by concentrations and safety assessment carried out by the cell viability of Taraxaci Herba, Gardeniae Fructus, Chrysanthemum indicum and Lonicerae Flos composition and concentration. We found cell survival were higher than the control group show a beneficial trend in the growth of normal liver and kidney cells. As a results of this study will be the basis to develop the hangbang-tea differentiated in the future oriental medicine resources. Medicinal resources will be hangbang-tea based on clinical trials utilizing herbal western and oriental medicine convergence principle and vascular relaxation mechanism.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.583-586
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• 2003

부산 동래지역 지열수에 대한 지화학적 진화과정을 밝히기 위하여 지열수, 지하수 및 해수에 대한 수리화학 특성과 이들의 연관성을 고찰하였다. 또한 심부환경에서의 지화학 특성을 규명하기 위하여 각종 이온지질온도계와 다성분 지질온도계를 적용하였으며, 동위원소특성과 함께 지화학 모델링을 통하여 심부환경에서의 온천수의 지화학특성을 밝히고자 하였다. 동래 지열수의 수리화학적 특성은 해수의 영향을 받아 높은 이온함량을 보이며 Na-Cl형을 보여준다. 지열수는 주변 지하수와의 크게 혼합된 양상을 나타낸다. 지화학 모델링에 따르면 지열수는 심부에서 약 5% 영향을 받은 것으로 추정된다. 즉, 심부로 순환하는 지열수가 해수와 혼합되며, 이들이 지열에 의해 가열되면서 광물의 용해 및 침전, 이온 교환반응 등 물-암석 반응을 거치면서 심부지열수를 형성하였으며, 지열수가 천부환경으로 상승하는 과정에서 동래지역 주변 천부지하수와 다양하게 혼합되면서 현재 동래온천수의 화학조성을 갖는 온천수를 형성하는 것으로 지열수의 진화 과정을 설명할 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.832-835
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• 2009

폐기물의 감량화 및 자원화 기술 중 가장 대표적인 기술로 폐기물의 가스화 용융 기술을 들 수 있다. 폐기물 가스화 용융 기술은 폐기물 내의 탄소 및 수소 성분은 가스화 하여 CO, $H_2$가 주성분인 합성가스(synthesis gas, syngas)로 전환하고, 불연물은 용융하여 환경적으로 무해한 슬래그 또는 금속으로 회수하는 기술이다. 본 연구에서는 고발열량폐기물과 탈수슬러지 혼합가스화를 통하여 생산된 합성가스를 합성가스 압축기를 통하여 유용한 원료물질을 제조하는 공정인 수성가스 전환 반응(water gas shift reaction)과 가스화 반응기의 보조연료로 투입하기 위한 합성가스 압축, 이송 시스템의 운전 특성을 고찰하였다. 그 결과 고발열량폐기물과 탈수슬러지 혼합가스화에서 합성가스는 안정적으로 발생하였으며, 합성가스 압축, 이송시스템을 위한 정제설비에서의 분진제거는 99.07 %의 효율을 얻었고, 또한 합성가스 재순환 장치의 성능시험을 통하여 대기 중의 산소가 유입이 안 되는 기밀성을 확인하였다. 합성가스 압축, 이송 공급 유량 제어 실험 결과로는 합성가스 압축기 기동 시 합성가스 압축압력과 공급유량은 비례적으로 증감하는 것을 알 수 있었다.

• Journal of Korea Water Resources Association
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• v.41 no.5
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• pp.463-471
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• 2008

The purpose of this study is to analyze the features of groundwater use to utilize as basic information for water-cycle analysis system development and effective groundwater management in the Kap-cheon basin. The cumulative relationship between groundwater use and the number of wells was analyzed to estimate the representative total groundwater use and the number of wells for the Kap-cheon basin. Then, the spatial distribution of groundwater use in the basin were figured out using the detailed information on groundwater use in each well. Finally, the reasonability of groundwater resources management in Kap-cheon basin was evaluated by comparing groundwater recharge and groundwater use in sub-basins and major stream basins. The results of the analysis showed about 25% of the total wells could represent 90% of groundwater use ($37,923,516\;m^3$/year) in the Kap-cheon basin. A detailed analysis on the groundwater uses in the vicinity of down-town areas of Daejeon metropolitan city showed high groundwater uses ($1.4{\sim}11.1$ times) compared to the groundwater recharge previously estimated using the rainfall-runoff model. The ratio of groundwater use and groundwater recharge for the major river basins in Kap-cheon basin ranged from 1.9 to 2.3 indicating that more sustainable groundwater management should be exercised. The results of this study can be used as basic information in evaluating the change of groundwater flow, stream flow and water-cycle for various groundwater uses in the Kap-cheon basin.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1310-1314
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• 2008

수도권 지역의 신도시 개발에 따른 유역의 도시화와 인구 증가는 유역의 피복상태를 변화시키고, 생태계에 영향을 미치는 수문학적 과정과 하천수질의 변화를 초래하게 된다. 지표면의 침투, 침루 및 토양함수량을 변화시키고, 차단저류량과 요지저류량(depression storage) 등을 변화시킴으로서 유출량과 수질을 변화시키게 되는 것이다. 이와 같은 수문학적과정을 평가하기 위해서는 수문모형을 사용하는데 본 연구에서는 미국 농림부에서 개발한 SWAT모형을 이용하였다. SWAT-K모형은 SWAT(Soil and Water Assessment Tool) 모형에 인위적, 자연적인 물순환 구조변화와 지표수-지하수 연계 해석 등을 개선하여, 강우 증발산 토양수분 지표수 지하수 등의 시, 공간적 분포를 정량적으로 산정하는 장기유출 해석 모형이다. 또한, 본 모형의 적용을 위하여 GIS를 이용한 공간정보를 처리하여 수문모형의 매개변수를 결정하는 방법이 널리 사용되고 있는데, 본 연구에서는 ArcView GIS를 이용하여 입력자료를 구축하였다. 대상유역은 판교유역으로서 신도시 개발이 한창 진행되고 있는 지역으로서, 개발 과정에 따라 수문특성, 유출특성, 수질변화 특성 등이 계속하여 변화되고 있으며, 개발이 완전히 종료된 이후의 특성을 예측할 필요가 있는 유역이다. 본 연구에서는 SWAT-K모형을 이용하여 판교 신도시 개발에 따른 장기유출량을 예측하였고 모델의 매개변수를 최적화하였으며, 그 결과 본 모델이 장기 유출량 해석 및 판교유역의 수문변화를 평가하는데 유용하게 적용될 수 있을 것으로 판단되었다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.4
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• pp.400-406
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• 2023

In this study, the relationship between the material properties and air permeability characteristics was examined, an experimental method to analyze the air permeability characteristics was presented, and experimental results were derived. The effects of compressive strength and apparent density of hardened concrete on air permeability characteristics were evaluated experimentally. Focusing on the mix proportions used in nuclear power plant concrete structures, concrete test specimens were manufactured and air permeability characteristics were measured according to changes in binder, maximum aggregate size, and water-binder ratio. The apparent density was over 2,400 kg/m³ for the OPC mix and the FA-35 mix, and the air permeability for both mixes were low, in the range of 0.1-0.2 L/min. On the other hand, in the case of the combination of FA-40, FA-45, and FA-M, the apparent density was measured to be less than 2,400 kg/m³ and the air permeability was measured to be more than 0.3 L/min, experimentally verifying that the apparent density is an important factor in air permeability characteristics.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.4
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• pp.308-315
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• 2013

Water emulsion technology has the problem of unstable combustion due to the rapid separation of water. To solve the problem, a hybrid mixing device was developed. The device attached on the burner was tested. As a result, the fuel consumption reduced to 12% in the similar condition of exhaust emissions and flame temperature, and 45.5%, 98.5% and 97.2% of NOx, CO, and smoke were reduced at the same inlet air and fuel flow rate.