• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1162-1167
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• 2004

From the early 1980's, the New Austrian Tunnelling Method (NATM) has been developed as a one of the standard tunneling method in Korea. Owing to the results of many researches, the practical problems of shotcrete has been improved for a last decade. However, the excess amount of rebound still remains one of the critical problems in shotcrete technology. In order to improve for this rebound problem, recently developed cement mineral accelerator has been successfully applied to several NATM tunnels in Korea. An experimental investigation was carried out in order to verify the rebound characteristics of wet-mix Steel Fiber Reinforced Shotcrete (SFRS) with powder types cement mineral accelerator. Mortar setting test, SEM analysis, bonding test under spring water condition and rebound test were conducted. From the result, wet-mix SFRS with cement mineral acelerator exhibited excellent bonding characteristics even spring water condition and less rebound ratio compared to the conventional liquid accelerator.

• Asian-Australasian Journal of Animal Sciences
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• 제23권12호
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• pp.1594-1600
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• 2010

A study was conducted to determine the dietary effects of a clay mineral (sodium bentonite, NaB) on manure gas emission, health, production, and meat characteristics of Hanwoo steers. Two diets fed to steers included a control diet (concentrate mix and rice straw) and a treatment diet (control diet+1.0% clay mineral/concentrate mix). Dietary NaB addition considerably reduced concentrations of gases ($H_2S$, $SO_2$ and $NH_3$) in the manure of Hanwoo steers. Growing steers fed NaB had similar blood profiles with the exception of lower (p<0.05) concentrations of blood alkaline phosphatase and lactate dehydrogenase. Dietary NaB addition tended to increase (p = 0.10) live weight by 30 kg at slaughtering and did not affect carcass yield and quality traits. Dietary NaB addition increased concentrations of P (p<0.01), Mg (p<0.01), Na (p<0.01), Zn (p<0.005), K (p = 0.08), Fe (p = 0.08) and Cu (p = 0.07) in the longissimus muscle compared to the control but did not affect (p>0.05) fatty acid composition. The study demonstrated that the dietary addition of a clay mineral could be effective in improving mineral bioavailability to Hanwoo steers, which could be one of the reasons for their improved performance.

• 한국토양비료학회지
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• 제39권5호
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• pp.245-252
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• 2006

우리나라 토양의 분류체계를 보완하고 점토광물 조성과 분포를 파악하기 위하여 우리나라 390개 토양통 중 잔적 및 붕적토에서 유래된 26개 토양통을 대상으로 토양 층위별료 시료를 채취하여 집적층을(B층) 토양의 이화학적 특성, 토양 중 점토의 광물조성과 화학성분을 분석하였다. 잔적 및 붕적모재별로는 화강암과 화강편마암, 회장암에서 유래된 토양에서 kaolin과 quartz, 유문암, 3기층, 석영반암, 응회암에서 유래된 토양에서 quartz과 kaolin, 석회암, 혈암, 사암, 역암 등 퇴적암에서 유래된 토양에서 illite와 chlorite가 주요한 점토광물이었다. 토양통별 점토광물조성을 군집분석 (CA, cluster analysis)을 통하여 (1) illite, kaolin, vemiculite를 주광물로 하는 혼합점토광물군 (MIX), (2) kaolin을 주광물로 illite가 많은 kaolin군 (KA), (3) chlorite와 illite가 주광물인 chlorite군 (CH), (4) kaolin과 illite를 주광물로 smectite가 함유된 smectite군 (SM) 등 4개의 점토광물 조성군으로 구분하였다. 우리나라 토양의 대부분은 kaolin을 주광물로 하는 토양과 illite, kaolin, vemiculite가 함유된 토양이었으며, illite와 kaolin을 주광물로 하는 토양에서 CEC가 낮았고 vemiculite와 smectite가 함유된 점토에서 규반비가 높았다.

• 한국농공학회논문집
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• 제62권4호
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• pp.23-31
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• 2020

Recently, meteorological disasters have been increasing by climate change, excessive rainfall, and landslide. The purpose is to develop new fabric concrete that can prevent and recover from damages because some of areas are vulnerable to meteorological disaster. Specifically, this technology can minimize time and space constraint when repairing the concrete structure and installing a formwork. The structure of fabric concrete is a mixture of fabric concrete and a high-speed hardened cement, Silica sand, wollastonite mineral fiber, fabric material and waterproof PVC fabric. In this study, the ratio of mechanical properties and durability of the fabric concrete mixture was evaluated by deriving the binder: silica sand mix ratio of the fabric concrete mixture and substituting part of the cement amount with wollastonite mineral fiber. Best binder in performance evaluation: Silica sand mix ratio is 6: 4 and the target mechanical performance and durability are the best when over 15% wollastonite binder is replaced by silicate mineral fiber.

• 한국건축시공학회지
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• 제9권5호
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• pp.127-133
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• 2009

일반적으로 콘크리트를 고강도화 하기 위해서는 결합재의 강도를 증가시키는 것이 중요하다. 그러나 고강도 콘크리트에 사용되는 광물질 혼화재들이 가진 고결현상으로 인해 개별투입 혼합 시에는 분산성이 크게 저하되어 유동성을 저감시키고, 충분한 강도를 발휘하지 못하는 문제가 발생한다. 이러한 문제를 해결하기 위해 각각의 결합재를 사전에 프리믹스하여 콘크리트를 제조하게 되면 광물질 혼화재가 충분히 결합재 중에 분산되어 콘크리트의 유동성 향상 및 강도증진 등에 기여할 수 있을 것으로 기대된다. 따라서 본 연구에서는 W/B $15{\sim}35%$ 범위내에서 프리믹스 시멘트의 효과를 분석하기 위해 결합재의 혼합방법에 따른 고강도 콘크리트의 물성을 분석하였다. 그 결과 유동성은 프리믹스의 균일분산 및 볼 베어링 효과로 인해 개별혼합보다 양호한 결과를 나타내었고, 공기량은 프리믹스의 시멘트 입자간 공극을 실리카퓸의 미세한 입자가 충전하는 마이크로 필러 효과로 인해 개별혼합 보다 약간 감소하였으며, 응결시간은 프리믹스의 균질한 분산이 수화발열속도에 영향을 주어 개별혼합보다 단축되었다. 압축강도는 프리믹스의 공극구조 치밀화로 인하여 증가하였으며, 강도편차 또한 평균적으로 약 1.69 % 정도 변동계수가 감소하는 효과를 나타내었다.

• 자원환경지질
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• 제57권3호
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• pp.305-317
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• 2024

토양 내 미생물 군집의 변화가 비소 용출에 미치는 영향을 파악하기 위해 비소 오염 토양(F1, G7, G10)을 대상으로 실험을 수행하였다. 실험은 혐기적 조건에서 비소 오염 토양을 ① BAC: 멸균토양 + Bacillus fungorum, ② IND: 토착균 토양, ③ MIX: 토착균 토양 + B. fungorum으로 나누어 혐기적 조건에서 유산염을 탄소원으로 하여 7주간 배양하였다. 실험 결과, 토착균 군집이 존재하는 IND와 MIX에서 BAC에 비하여 높은 함량의 비소가 용출되었으며, pH가 높은 G10 토양에서 F1과 G7 토양에 비해 비소 용출량이 월등히 높았다. G10 토양의 경우, 다른 토양과 달리 용출된 비소 중 As(III) 함량의 비율이 낮았다. 이러한 결과는 토양에 따라 상이하게 나타나는 미생물 군집의 차이에 기인할 수도 있다. IND와 MIX는 7주차에 이르러 미생물의 다양성이 크게 감소하였으며 실험 조건에 적응한 Eubacteriales 및 Bacillales 등의 우점목이 번성하였다. F1 토양의 7주차 MIX에서는 Bacteroidales, G7 토양의 7주차 IND와 MIX에서는 Rummelibaciilus가 번성하였다. G10 토양의 IND와 MIX에서는 Enterobacterales가 우점목 중 하나를 차지하였다. 현재로서는 미생물 군집의 변화가 비소의 지구화학적 거동에 어떠한 메커니즘으로 영향을 미치는지에 관한 정보가 부족하나, 이러한 결과는 토양 내 마이크로바이옴이 비소의 용출을 조절하는 요인 중 하나로 기능할 수 있음을 나타낸다.

• 한국세라믹학회지
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• 제50권2호
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• pp.134-141
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• 2013

Pond ash produced from Seochun Power Station was quantitatively characterized to manufacture geopolymers with a range of Si/Al compositional ratios. Mix consistency was kept nearly constant for comparing the compressive strengths of geopolymers. The amorphous composition of coal ash was determined using XRF and quantitative X-ray diffraction. Different mix compositions were used in order to achieve Si/Al ratios of 2.0, 2.5 and 3.0 in the geopolymer binder. Geopolymers synthesized from coal ash with a Si/Al ratio of 3.0 exhibited the highest compressive strength in this study. It was found that geopolymers activated with aluminate produced different microstructure from that of geopolymers activated with silicate. High silica in alkali activators produced the fine-grained microstructure of geopolymer gel. It was also found that high compressive strength was related to low porosity and a dense, connected microstructure. The outcome of the reported experiment indicates that quantitative formulation method made it possible to choose suitable activators for achieving targeted compositions of geopolymers and to avoid efflorescence.

• Asian-Australasian Journal of Animal Sciences
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• 제12권5호
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• pp.735-741
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• 1999

The effects of supplementation with nitrogen molasses mineral blocks and molasses urea mix during and immediately prior to the dry season on the production of dairy cows were studied on-station and on-farm near Morogoro, Tanzania. Supplementation of blocks to on-station cows also receiving ad libitum grass hay and 6 kg/d of maize bran increased milk production from 6.7 L/d to 11.2 L/d (p<0.05), increased dry matter intake from 10.1 kg/d to 12.0 kg/d (p<0.05), but did not significantly affect milk composition, intake of hay, and live weight changes. This increase in milk yield is mainly explained by increased intakes of energy and nitrogen. Supplementation with the molasses urea mix increased daily milk yield from 6.7 L/d to 8.8 L/d (p<0.05), but did not significantly affect the other measured production parameters. The on-farm supplementation of the blocks increased daily milk yield by 1.5 L/d in the dry season (p<0.05). This supplementation did not increase milk yields prior to the dry season, since quality forage was still available. Taking the production costs into account, supplementation with the blocks and supplementation with mix were cost effective if milk yields increased by 0.7 L/d. Hence supplementation with blocks and supplementation with mix were effective on-station, and supplementation with blocks was cost effective on-farm during the dry season.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.175-178
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• 1999

In most domestic construction fields, excessive cement content has been used because of stubborn official inspection. The purpose of this study is to reduce the cement content of mix proportioning for the decrease of hydration heat, brittleness and drying shrinkage which governs durability of concrete significantly. Parameters includes the compressive strengths, type and dosage rate of chemical and mineral admixtures and types of concrete. It is found that the chemical admixture is efficient to the reduction of cement content for high strength concrete (400kg/$\textrm{cm}^2$) and the effectiveness of mineral admixtures in the low strength concrete is somewhat higher than the high strength concrete.

• Animal Bioscience
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• 제36권12호
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• pp.1842-1852
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• 2023

Objective: Hairy vetch is considered to improve the nutritional value of corn because of its high protein and mineral levels. To better understand the mechanism underlying hairy vetch regulated whole-plant corn silage fermentation, this experiment investigated the fermentation quality and bacterial community of whole-plant corn and hairy vetch mixture. Methods: Whole-plant corn and hairy vetch were mixed at ratios of 10:0 (Mix 10:0), 8:2 (Mix 8:2), 6:4 (Mix 6:4), 4:6 (Mix 4:6), 2:8 (Mix 2:8), and 0:10 (Mix 0:10) on a fresh weight basis. After ensiling 60 days, samples were collected to examine the fermentation dynamics, ensiling characteristics, and bacterial communities. Results: Mix 0:10, Mix 2:8, and Mix 4:6 showed poor fermentation characteristics. Mix 8:2 and Mix 6:4 silages showed high quality, based on the low pH, acetic acid, and ammonia nitrogen levels and the high lactic acid, crude protein, and crude fat contents. The bacterial diversity was affected by the mixing ratio of the two forage species. The genus Lactobacillus dominated the bacterial community in Mix 10:0 silage, whereas with the addition of hairy vetch, the relative abundance of unclassified-Enterobacter increased from 7.67% to 41.84%, and the abundance of Lactobacillus decreased from 50.66% to 13.76%. Conclusion: The silage quality of whole-plant corn can be improved with inclusion levels of hairy vetch from 20% to 40%.