• 한국해양학회지
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• 제24권1호
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• pp.39-51
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• 1989

한국 동남해역의 대륙붕과 대륙사면에서 채취된 139개의 표면퇴적물 시료의 입도특성과 광물성분 및 유기탄소 함량이 분석되었다. 퇴적물의 입도특성에 의하여 사질퇴적상, 점토질퇴적상, 이토질퇴적상, 사니혼합퇴적상 빚 사점토혼합퇴적상 등 5개의 퇴적상이 구분될 수 있었고, 이들의 지역적인 분포 양상이 해석되었다. 한편, 본 연구지역의 퇴적물은 한반도 주변의 다른 해역환경에 비하여 전반적으로 점토의 함량이 높은 반면 상대적으로 실트의 함량이 빈약한 것이 특징적이다. 사립의 광물성분은 주로 석영, 장석 및 암편으로 구성된다. 중광물의 조성은 지역적 특징을 나타내어, 연구지역의 남부에서 ZTR 광물(zircon, tourmaline, rutile)이, 북부에서 변성기원 광물이, 그리고 후포뱅크에서 석류석이 각각 타 지역에 비하여 풍부했다. 한편, 점토광물 중에서는 일라이트가 가장 우세하였으며(평균 64%), 클로라이트(20%), 카올리나이트(13%), 스멕타이트(4%) 순으로 그 함량이 감소하였다. 퇴적물의 유기탄소 함량은 평균 1.94%로서, 한반도 주변의 다른 해역들에 비하여 높았다. 유기탄소의 함량은 주로 퇴적물 입도에 의해 조절되며, 지역적으로는 대륙사면의 퇴적물에서 특히 높았다. 퇴적물의 입도와 광물성분의 지역적인 분포양상은 연구지역의 북부와 남부가 세립퇴적물의 공급 및 이동경로에 있어 서로 다르다는 사실을 시사한다. 이 해역에서 보고된 수온이나 해류에 관한 연구결과들은 이렇게 서로 다른 세립질 퇴적물의 이동 양상을 뒷받침해 주는 것으로 보인다.

• 한국작물학회지
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• 제27권3호
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• pp.276-282
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• 1982

본 시험은 1981년에 참깨품종 "수원 9호"를 Pot에 공시하여 토양의 배수력 차이에 따른 참깨의 생육과 수량형성의 차이를 구명하고자 시도되었다. 즉 점토와 세사를 용량비(V/V Ratio)로 각각 0:100, 25:75, 50:50, 75:25 및 100:0가 되도록 혼합한 토양에 6일 간격 20mm 관수와 3일 간격 10mm 관수의 효과와 반응차이를 해석하였다. 토양의 용량비에 따른 수분의 배수성은 점토혼합율에 따라 거의 직선적으로 감소하는 경향이었다. 토양배수성 차이에 따른 참깨의 생육반응은 순세사토에서만 한해가 인정되므로 관수의 증대가 요구되었고 그 외의 배수조건의 차이에 따른 생육반응에는 통계적 유의차가 없었다. 수량구성요소 가운데서 수량에 기여도가 가장 컸던 것은 주당삭수로서 수량과 마찬가지로 점토와 사토가 75%:25%로 혼합된 조건 즉 배수성보다는 보습성이 양호한 토양에서 가장 많았으며 삭당입수나 등숙성은 선행형질인 주당삭수와의 부적상관 때문에 보습성 보다는 배수성이 양호한 토양에서 증대되는 경향을 나타내었다. 관수방법간에 이들 수량구성 특성의 차이는 없었으나 수량은 6일 간격 20mm보다 3일 간격 10mm 관수로서 보습력(점사율 75%:25%)이 높은 조건에서 최다수준이었으며 과도한 배수성이나 보습성의 조건에서는 뚜렷한 감수의 경향이었다.감수의 경향이었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.175-178
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• 2003

There is a case to use dredged-sea sand as a filling material because of difficulty of obtaining required filling material for tideland reclamation project from the land. At this time, side slope erosion is occurred because the precipitation falling to the top of bank acts as infiltration water when it pass through inside of the semi-permeable filling section. This study has confirmed the declining effect of permeability by conducting permeability test to the condition of mixing of bentonite to the dredged sea-sand. And also this study has confirmed that the above processed-soil could be used as a water-proof layer to protect infiltration of water through the infiltration flow analysis.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.277-283
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• 1998

In this study we changed W/C into 45, 50, 55, 60%, mixed sea sand which is often used as a replacing aggregate according to the lack of recourse with river sand in the ratio of 5:5 and producted antiwashout underwater concrete. We measured slump flow, air value, pH and suspension in the fresh concrete. After testing each W/C through unit weight and compressive strength of specimen which is produced and cured in the air and salt water it was founded that if sea sand was properly used after salt manufacturing, there will be no bad influence to antiwashout underwater concrete. The characteristic of them showed excellent, when W/C was 50%.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.223-228
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• 1997

In this study, bottom ash, lightweight aggregate, and Expanded Polystyrene was used to lighten the mortar. In order to compensate the reduction of strength caused by lightening, the waste foundry sand produced as solid waste was substituted for fine aggregate. As the device of reducing the ratio of absorption, the procedure of mixture was altered to check the effectiveness of surface coating of porous lightweight aggregate. It was observed over 170kg/$\textrm{cm}^2$ compressive strength at gravity about 1.3, an over 380kg/$\textrm{cm}^2$ at gravity about 1.7. the maximum strength was occurred when 30% of fine aggregate was replaced was replaced with waste foundry sand, and the ratio of absorption was decreased over 10% by changing the procedure of mixture.

• 한국세라믹학회지
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• 제13권1호
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• pp.20-24
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• 1976

These are many kinds of self-hardening methods for sand mold using sodium silicate. When sodium silicate solution is mixed with calcium-orthosilicate powder hardening reaction occurs, which is based for self-hardening method at high temperature. The high temperature strength and resicual strength of mold are related to the mole ratio of sodium silicate and the contents of calcium-orthosilicate powder. The results obtained in this study were as follows: 1) The high temperature strength of mold was maximum at about $600^{\circ}C$, and at higher temperature showed lower value on the contrary. 2) The high temperature strength of mold was increased by increasing the amount of sodium silicate having lower mole ratio and high concentration. 3) The residual strength of mold was reduced by increasing the mole ratio of sodium silicate and increasing the concentration of calcium-orthosilicate.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2001년도 추계학술발표대회 논문집 제20권 2호
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• pp.223-226
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• 2001

Acoustic pressure transmission coefficient and phase velocity are measured as the functions of water porosity and air porosity in sand sediment slabs with water- and air-filled pores. Pores in the sand sediment slab we modeled as the structure of circular cylindrical tube shape filled with water and air. The first kind(fast) wave and second kind (slow) wave, identified by Biot, in the solid and fluid mixed medium are affected by the presence of water and air pores. Acoustic characteristics of such porous medium in water are also theoretically investigated in terms of the modified Biot-Attenborough (MBA) model, which uses the separate treatment of viscosity effect and thermal effect in non-rigid porous medium with water- and air-filed pores. The information on the fast waves introduces new concepts of the generalized tortuosity factor and dynamic shape factor.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1992년도 가을학술발표회 논문집
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• pp.47-54
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• 1992

When marine clay is hydraulically dredged from seabed and pumped into the pond enclosed by contatinment dykes, marine clay is mixed and flocculated with water and then settled. At this time, the fines will interact with the water to form a Bingham plastic slurry which has non-Newtonian characteristics. The dredged slurry has different physical properties depending on settling locations and settling depths in the pond and has few hundred percent of water content and almost nil of shear strenght. In order to make this condition of the dredged slurry the final formation for public use within a short period, sand spreading method to enhance the support capacity of the dredged slurry is developed. In this paper, the effect of sand mixing into the dredged slurry of this method is analyzed based on reference study, laboratory tests and actual construction results.

• 한국동물위생학회지
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• 제33권1호
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• pp.75-80
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• 2010

Eggs of parasite were found 73 of 1,459 in sand samples from public parks and playgrounds in Incheon for 5 years (from 2004 to 2008). Of the 1,459 sand samples examined, 17.8% of samples were found to be positive ova of Toxocara canis, 11.0% for Toxocaris leonina, 5.5% for Toxocara cati, 2.7% Ancylostoma caninum and 1.4% for Strongyloides spp. It was found mixed infestation with Toxocara canis and Toxocara cati 60.2%.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.350-357
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• 2002

The scale effect should be considered to determine the bearing capacity and settlement of footings from Plate-Load Test, because of the size difference between a footing and a loading plate. To analyze characteristics of bearing capacity and settlement according to the difference of loading plate sizes, model tests were peformed with four different sizes of square plate, which is B=10, 15, 20 and 25cm respectively, on five different kinds of subsoil, which is pure sand(100:0), sand-clay mixed soil(75:25, 50:50, 25:75), and pure clay(0:100). Based on the analyzed results, this paper also proposed a method of bearing capacity and settlement determination, where scale effect is considered depending on the mixing ratio of sand and clay. Applying the formular proposed in this research to field problems, it is expected that evaluation of bearing capacity and settlement of footings can be more reliable and more economic construction can be achieved.