• 지질공학
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• 제18권1호
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• pp.69-81
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• 2008

산사태연구는 산사태를 발생시키는 여러 인자들의 상호관계를 규명하는 방법, 확률론적으로 산사태 발생가능성을 예측하는 방법 사태물질의 이동경로와 확산범위를 산정함으로써 산사태 위험성을 평가하는 방법 등으로 구분할 수 있다. 우리나라에서 발생된 대부분의 산사태는 여름철의 집중호우에 기인되는 것으로 기반암 상부의 토층에서 발생되며, 강우조건, 지형조건과 지질 및 토질특성 등에 영향을 받는 것으로 알려져 있다. 산사태 조사부터 위험성평가에 이르기까지의 산사태연구는 다양한 산사태를 체계적으로 조사하고 해석함으로써 공학적 관점에서 여러 특징들을 관찰하고 그 특성들을 총괄적으로 해석하여야만 한다. 이 연구에서는 경상남도 마천지역을 대상으로 산사태 현장조사를 수행하였다. 조사결과를 토대로 자연사면 산사태에 대한 최적의 표준모델로 활용할 수 있는 산사태 조사 및 해석 기법을 제안하고자 한다.

• 대한지하수환경학회지
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• 제5권4호
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• pp.203-209
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• 1998

The quality of groundwater used for natural mineral water should be strictly regulated on international level by hydrogeology experts and officials because groundwater is greatly subjected to contaminations and its aquifer system may be easily destroyed by external reasons. A total of 18 natural mineral water plants exist in Precambrian metamorphic terrains of the Gyunggi massif and Yeungam massif. The g개undwater quality for the natural mineral water investigated in hydrochemical aspects shows that pH ranges from 6.85 to 8.02 with an average of 7.52. The electric conductivity (EC) and hardness average 134.1 $\mu$S/cm and 43.5, respectively, which are relatively low to the total average (151.4 $\mu$S/cm and 57.9). The contents of major cations and anions are in the order of $Ca^{2＋}$＞$Na^{＋}$＞Mg$^{2＋}$＞K$^{＋}$ and HCO$_3$$^{-}$ ＞SO$_4$$^{2－}$ ＞Cl$^{-}$ ＞F$^{-}$ , respectively. The dominant water types determined by Piper diagram are $Ca^{2＋}$－$Na^{＋}$－HCO$^{-}$ $_3$and $Ca^{2＋}$-HCO$^{-}$ $_3$, mainly due to the dissolution of plagioclase in the host rocks. Representative correlation coefficients between chemical species are $Ca^{2＋}$－HCO$^{-}$ $_3$(0.92), $Ca^{2＋}$－Cl$^{-}$ (0.63), $Na^{＋}$－F$^{-}$ (0.67), HCO$^{-}$ $_3$－Cl$^{-}$ (0.66), and $Na^{＋}$－HCO$^{-}$ $_3$(0.63). The determinative. coefficients between $Ca^{2＋}$ and HCO$^{-}$ $_3$, and (Ca$^{2＋}$＋$Na^{＋}$＋K$^{＋}$ and EC art highest among the elements. According to the saturation index, most chemical species are undersaturated with respect to major minerals, except for some silica phases. In viewpoint of phase equilibrium, the chemical evolution of the groundwater may continue to proceed with increasing pH because the groundwater is undersaturated with respect to feldspars.

• 지질공학
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• 제12권4호
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• pp.395-404
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• 2002

국내 먹는샘물의 수질기준치를 초과할 가능성이 있는 수질 항목에 대해 취수정의 심도와 지질을 연관시켜 고찰하였다. 5년 간(1998~2002)의 수질분석 결과에 의한 질산성질소의 평균 함량 범위는 0.8~1.09 mg/L, 불소의 평균 함량은 0.37~0.45 mg/h, 수소이온농도의 평균은 7.30~7.59이다. 이는 비슷한 도의 일반 지하수와 유사한 값을 보여서 천부 지하수의 유입 가능성을 지시한다. 전반적으로 이들 수질항목과 취수정의 심도, 지질과는 뚜렷한 관련성을 보이지 않는다. 먹는샘물의 평균 비소함량은 1999년의 0.0024 mg/L에서 2002년의 0.0066 mg/L으로, 비소 함량이 0.001 mg/L 이상인 먹는샘물 제조 업체의 비율도 1999년에 20.1%에서 2002년에 64.9%로 증가하고 있다. 2002년 현재, 향후 USEPA의 음용수 중 비소함량 기준으로 예상되는 0.01 mg/L을 초과하는 먹는샘물 제조업체 수는 57개소 중 11개소이다.

• Journal of Microbiology and Biotechnology
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• 제8권2호
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• pp.124-128
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• 1998

The procedures currently used for determining microbiological quality of natural mineral water recommend filtration through membrane filters. In this study, we evaluated the effect of vacuum pressure for the accurate detection of bacteria from water samples seeded with Escherichia coli. We observed that the number of E. coli detected increased with increasing vacuum pressure. In order to examine the retention rate of bacteria in the holes of the membranes under the different pressures, the membrane filters were removed after filtration, washed with sterile water by vortexing, and placed on m-Endo agar plates. With all the filters tested, the number of E. coli retained within the filters at negative 600 mmHg was approximately 10 to $20\%$ higher than that obtained with 100 mmHg. These results demonstrate that the vacuum pressure exerted during the filtration procedure may affect the fixation of bacteria into some portions of openings in the membrane filter.

• Advances in concrete construction
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• 제5권3호
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• pp.183-199
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• 2017

This paper reports an experimental study into the rheological behaviour of Smart Dynamic Concrete (SDC). The investigation is aimed at quantifying the effect of the varying amount of mineral admixtures on the rheology, setting time and compressive strength of SDC containing natural sand and crushed sand. Ordinary Portland cement (OPC) in conjunction with the mineral admixtures was used in different replacement ratio keeping the mix paste volume (35%) and water binder ratio (0.4) constant at controlled laboratory atmospheric temperature ($33^{\circ}C$ to $35^{\circ}C$). The results show that the properties and amount of fine aggregate have a strong influence on the admixture demand for similar initial workability, i.e., flow. The large amounts of fines and lower value of fineness modulus (FM) of natural sand primarily increases the yield stress of the SDC. The mineral admixtures at various replacement ratios strongly contribute to the yield stress and plastic viscosity of SDC due to inter particle friction and cohesion.

• 한국환경농학회지
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• 제19권1호
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• pp.38-43
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• 2000

Porphyrite(일명 맥반석), zeolite, bentonite를 혼합한 사료를 급여하면 가축의 영양에 긍정적 효과가 있는 것으로 보고된 바있다. 이렇게 발생된 분뇨를 토양에 투여하고 옥수수의 생육에 미치는 영향과 재배 후 포장의 이화학적 특성을 분석 검토하였다. 공시분은 모두 pH 8.0 이상이었고, CEC는 점토광물 혼합사료로 발생된 분이 일반분에 비해서 높아 혼합된 광물에 기인한 것으로 판단되었다. 분을 밑거름으로 옥수수를 재배한 결과 porphyrite > zeolite > 일반분 > bentonite 시용 포장의 순서로 생육이 양호하였고, porphyrite와 zeolite 처리구의 옥수수에서 N, P, K의 함량도 높게 나타났다. 옥수수 재래 이후 토양에서 유기물과 유효인산함량을 제외한 화학성은 분뇨처리구와 무처리구간, 그리고 각 광물 혼합 분뇨처리구간에 현저한 차이는 보이지 않았다. Zeolite와 bentonite 처리구에서 인삼함량이 특징적으로 높게 나타났다. 토성은 양토, 입단화도는 56-69%, 소성하한은 22-23%, 투수계수는 $3.29{\times}10^{-5}{\sim}6.04{\times}10^{-6}\;cm{\cdot}sec^{-1}$의 범위로 처리구간에 유의적 차이가 나타나지 않았으며, 이는 처리가 1년 이내로 토양 물리성 개선효과를 거두기에는 너무 짧았기 때문으로 판단되었다.

• 한국광물학회지
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• 제32권2호
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• pp.145-150
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• 2019

최근 남북한 사이에 화해의 분위기가 무르익어가고 있으므로, 미래에 발생할 한반도 통일을 대비하는 관점에서 남북한 사이의 광물명을 통일하여 사용하는 것이 절실히 요구되고 있다. 외래어 표기법에 다른 언어에서 빌려온 어휘를 한글로 표기하는 규정이 있음에도 불구하고 광물명의 경우 이를 준수하지 않고 같은 외래어 광물명에 대하여 다양한 용어를 사용하고 있으므로 외래어 표기법에 맞도록 통일해야 한다. 금속광물과 비금속광물 모두에 ${\bigcirc}{\bigcirc}{\bigcirc}$석을 사용하고, 외래어 표기법 용례 찾기에 포함된 약 70개의 광물명은 용례 찾기에 나와 있는 대로 표기하고, 인명이나 지명에서 유래한 광물명은 인명이나 지명 + 석으로 표기할 것을 제안한다.

• Journal of Forest and Environmental Science
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• 제37권2호
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• pp.116-127
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• 2021

Predicting carbon distribution of soil aggregates is difficult due to complexity in organo-mineral formation. This limits global warming mitigation through soil carbon sequestration. Therefore, knowledge of land use effect on carbon stabilization requires quantification of soil mineral cations. The study was conducted to quantify carbon and base cations on soil mineral fractions in Natural Forest, Plantation Forest and Farm Land. Five 0.09 ha were demarcated alternately along 500 m long transect with an interval of 50 m in Natural Forest (NF), Plantation Forest (PF) and Farm Land (FL). Soil samples were collected with soil cores at 0-15, 15-30 and 30-45 cm depths in each plot. Soil core samples were oven-dried at 105℃ and soil bulk densities were computed. Sample (100 g) of each soil core was separated into >2.0, 2.0-1.0, 1.0-0.5, 0.5-0.05 and <0.05 mm aggregates using dry sieve procedure and proportion determined. Carbon concentration of soil aggregates was determined using Loss-on-ignition method. Mineral fractions of soil depths were obtained using dispersion, sequential extraction and sedimentation methods of composite soil samples and sieved into <0.05 and >0.05 mm fractions. Cation exchange capacity of two mineral fractions was measured using spectrophotometry method. Data collected were analysed using descriptive and ANOVA at α_0.05. Silt and sand particle size decreased while clay increased with increase in soil depth in NF and PF. Subsoil depth contained highest carbon stock in the PF. Carbon concentration increased with decrease in aggregate size in soil depths of NF and FL. Micro- (1-0.5, 0.5-0.05 and <0.05 mm) and macro-aggregates (>2.0 and 2-1.0 mm) were saturated with soil carbon in NF and FL, respectively. Cation exchange capacity of <0.05 mm was higher than >0.05 mm in soil depths of PF and FL. Fine silt (<0.05 mm) determine the cation exchange capacity in soil depths. Land use and mineral size influence the carbon and cation exchange capacity of Gambari Forest Reserve.

• 자원환경지질
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• 제27권6호
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• pp.537-548
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• 1994

The Weolyu gold-silver deposits at Hwanggan, Chungcheongbukdo, is of a late Cretaceous $(74.24{\pm}1.63Ma)$ epithermal vein-type, and is hosted in the quartz porphyry of late Cretaceous age. Based on mineral paragenetic sequence interpreted from vein structure and mineral assemblages, three stages mineralization were distinguished. A variety of ore minerals occurs including pyrite, sphalerite, chalcopyrite, galena with small amount of electrum, native silver, argentite, pearceite, sb-pearceite, argyrotite. The gangue minerals are quartz, rutile, calcite, apatite, fluorite and rhodochrocite. Wall-rock alteration such as pyritization, chloritization, sericitization, silicification is observed near the quartz veins. Au-Ag minerals were crystallized at middle and late stage of the two mineralization sequences. Results from the analysis of fluid inclusion and thermodynamic calculation indicate that Au-Ag mineral deposits were formed primarily by cooling and dilution of hydrothermal fluids($165{\sim}313^{\circ}C$, 0.4~2.4wt.% equivalent NaCl) with some degree mixing of meteoric water.

• Advances in concrete construction
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• 제11권3호
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• pp.231-238
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• 2021

The present work aims at investigating the effects of using various fine mineral additions as partial replacement to Portland cement on the tribological properties of concrete. To achieve this goal, concrete mixtures were prepared with different percentages (10, 20 and 30%) of limestone fillers (LF) and natural pozzolana (NP), and (20, 40 and 60%) of blast furnace slag (BFS). The interface yield stress (τ0) and viscous constants (η) that allow characterizing friction at the concrete-pipe wall interface were determined using a rotational tribometer. In addition, the compositions of the boundary layers that formed in the pumping pipes of the different concretes under study were also identified and analyzed. The experimental results obtained showed that the concretes studied have a linear tribological behavior that can be described by the Bingham model. Furthermore, the use of different mineral additions, especially limestone fillers and blast furnace slags, even at high rates, had a beneficial effect on the optimization of the volume of paste present in the boundary layer, which made it possible to significantly reduce the viscous constant of concrete. However, a maximum rate of 10% of natural pozzolana was recommended to achieve tribological properties that are favorable to the pumpability of concrete.