• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.335-342
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• 2000

In this study, the swelling characteristics of reconstituted clayey soil were investigated by STD and CRS test. The strain rate during loading was constant i.e. 0.05 %/min, 0.03 %/min and during unloading was varied in proportion to 1/1, 1/5, 1/10 and 1/15 of strain rate during loading. From this study the following conclusions were obtained; (1) There were similar values, especially, during unloading in case of 1/10 or 1/15 of strain rate during loading and the test results between STD and CRS were much to be alike. (2) The cross point of effective stress versus excess pore water pressure ratio curve, was increased during unloading, while the stress level of the cross point was decreased. The stress level can be separated into two zones according to the swelling index named Cs1 and Cs2. From the test results, the values of Cs1 were approximately constant irrespective of strain rate during unloading, but the values of Cs2 were much influenced by strain rate. (3) In CRS consolidation tests, it was found that unloading strain rate did not affect on the existence of zone.

• Geomechanics and Engineering
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• 제5권6호
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• pp.565-574
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• 2013

Extensive study was carried out on Clay expansive soil. This soil was silty clay and can be classified as CH. The degree of expansion was found to range from low to medium depending on the free swell and swell pressure tests. The research investigated the effect of using cement dust on swelling potential, Atterberg Limit, linear shrinkage, and mineralogical composition of expansive soil. The results showed that the swelling potential, plasticity index, linear shrinkage, and clay minerals decrease with increasing cement dust percentage. The cement dust accumulates in huge amounts as a side product in cement factories, and the disposal of this fine dust is very difficult and poses an environmental threat.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.774-781
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• 2009

The purpose of this study was to research on compressibility characteristics of waste tire powder-added lightweight soil(TLS) for recycling dredged soil, bottom ash and waste tire. The TLS used in this experiment consists of dredged soil, cement, waste tire powder and bottom ash. Test specimens were prepared with various content of waste tire powder ranged from 0% to 100% at 25% intervals by the dried weight of dredged soil. Several series of one-dimensional consolidation tests were carried out. Based on the experimental results, as the waste tire powder increased, the swelling index of TLS increased. The compression index and swelling index of the TLS with bottom ash content showed lower value than without bottom ash. Then, compressibility characteristics of TLS were strongly influenced by mixing conditions of waste tire powder content and bottom ash content.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제42권
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• pp.33.1-33.8
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• 2020

Background: We investigated the efficacy of a maxillary Jackson-Pratt (J-P) suction drain for preventing maxillary sinus hematoma and facial swelling after maxillary Le Fort I osteotomy (LF1). Methods: We retrospectively evaluated 66 patients who underwent LF1 at a single institution. Of these, 41 had a J-P suction tube inserted in the mandible and maxilla (maxillary insertion), and 25 had a J-P drain inserted in the mandible only (no maxillary insertion). Facial CT was obtained before and 4 days after surgery. We compared mean midfacial swelling and maxillary sinus haziness by t test and examined correlations between bleeding amount and body mass index (BMI). Results: For the maxillary-insertion group, the ratio of total maxillary sinus volume to haziness (57.5 ± 24.2%) was significantly lower than in the group without maxillary drain insertion (65.5% ± 20.3; P = .043). This latter group, however, did not have a significantly greater midfacial soft tissue volume (7575 mm³) than the maxillary-insertion group (7250 mm³; P = .728). BMI did not correlate significantly with bleeding amount or facial swelling. Conclusions: Suction drainage in the maxilla reduced maxillary sinus haziness after orthognathic surgery but did not significantly reduce midfacial swelling.

• 한국토양비료학회지
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• 제40권1호
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• pp.64-70
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• 2007

본 실험은 서로 다른 온도조건하에서 두 가지 Na 화합물을 이용하여 Ca-벤토나이트를 Na-벤토나이트 전환하였다. 두 가지 Na 화합물은 양이온 원으로 Na를 가지고 있는 5가지 화합물 중에서 선택하였다. 전환된 Na-벤토나이트의 팽창능은 Na의 농도가 높아질수록 증가하였으며 반면 온도가 증가할수록 최대 Na 농도는 감소하는 경향을 보였다. Na_2CO_3 은 조사된 Na-화합물 중에서 최대 팽창능을 보여주었으며 팽창지수는 처리온도가 최대 100 에 도달할 때까지 최고로 증가하였다. 동일 Na 처리농도에서는 팽창지수는 체류시간이 증가하거나 온도가 높아질 때 다소 감소하였다. 전환된 Na-벤토나이트의 흡착은 조사된 Pb나 Cd의 평형농도가 증가함에 따라 증가하는 경향을 보였으며 Pb의 흡착량이 Cd보다 다소 높은 것으로 조사되었다. 그리고 전환된 Na-벤토나이트에 Pb와 Cd의 흡착은 5 % $Na_2CO_3$. ${\approx}$ 5% $NaHCO_3$ > 3 % $NaHCO_3$ > 3 % $Na_2CO_3$ > 1 % $NaHCO_3$ > 1 % $Na_2CO_3$ > 원형 Na-B > 원형 Ca-B. 그러나 이러한 결과는 CEC에 따른 흡착의 결과와는 다소 상반되는 결과를 보여주고 있다.

• 한국해안해양공학회지
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• 제13권4호
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• pp.282-289
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• 2001

본 연구는 경남해안지역 연약점토의 토질특성과 압축지수와의 관계를 알아보기 위해 김해지역 82개소, 진해지역 18개소, 거제지역 27개소의 불교란 상태의 시료를 채취하여 물성실험 및 역학실험을 실시하였다. 그 결과, 경남해안지역 연약점토의 압축지수는 Terzaghi & Peck이 제안한 경험식을 적용할 수 없음을 알 수 있었다. 경남 해안지역 연약점토의 압축지수는 자연함수비, 액성한계, 초기간극비와 상관성이 있었으며, 이들 중 압축지수는 초 기간극비와 상관성이 가장 컸다. (1) 경남해안지역 연약점토의 압축지수는 $C_c=0.74(e_o-0.7$로 나타낼 수 있다. (2) 경남해안지역 연약점토의 압축지수와 팽창지수와의 관계는 $C_s=(1/8-1/15)C_c$이다.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.61-64
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• 2003

Optical resolution of a-amino acid (tryptophan and tyrosine) optical isomers was achieved by a pressure driven membrane separation process, using self-supporting crosslinked membranes base on polysaccharide with different swelling indices that ranged from 100 to 70%. The membranes prepared by casting and drying the polymer solution containing 5wt% acetic acid on an acryl plate followed by crosslinking with glutaraldehyde were characterized using such analytical methods as FTIR and swelling index measurements. On the way of separating the optical isomers, several experimental factors such as the concentration of the feed solutions, operating pressure and temperature, and degree of crosslinking of the membranes have been studied. When the chitosan membranes with 70% of swelling index were used , almost complete optical resolution was obtained; 97.92% of enantiomeric excess (ee %) and 2.26 g/$m^2$ㆍh of flux. The operating pressure and the concentration of feed solutions were respectively 1.0 kgf/$\textrm{cm}^2$ and 0.49 mmol/L.

• 공업화학
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• 제28권1호
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• pp.57-63
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• 2017

본 연구에서는 다양한 NCO index에서 물 함량 변화가 자동차용 폴리우레탄 시트 폼 패드의 정적 안락감에 미치는 영향을 알아보았다. 정적 안락감에 영향을 미치는 요인을 파악하기 위해 UTM을 사용한 정하중 특성 시험을 통하여 히스테리시스 곡선을 나타냈으며, 이를 통해 25% 변형 시 경도와 65% 변형 시 경도, hysteresis loop area, hysteresis loss (%), 그리고 Sag factor를 구하였다. 동일한 NCO index에서 물 함량이 증가함에 따라 우레아 결합의 증가로 경도가 증가하고, 가교밀도가 증가하는 경향을 swelling ratio 측정으로 확인하였으며, 이에 따라 복원력은 감소하는 경향을 확인하였다. 또한 표면 경도의 증가로 인해 Sag factor가 감소하는 경향을 확인하였다. 동일한 물 함량에서 NCO index가 증가함에 따라 우레탄과 우레아 결합이 이소시아네이트와 추가 반응하여 가교도와 경도가 증가하고 이에 따라 복원력이 감소함을 확인하였다.

• 대한본초학회지
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• 제25권4호
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• pp.95-102
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• 2010

Objectives : Specifications by Processing Methods of Liriope platyphylla (LP) was not established in korea. We carried out method study for manufacture of LP. Above all, LP were purchased and were processed at four kinds. First group had hearts of swelling roots, not cut bodies(LP-A). Second group had not hearts of swelling roots, not cut bodies(LP-B). Third group had hearts of swelling roots, cut bodies(LP-C). Forth group had an aggregate of hearts of swelling roots(LP-D). Methods : We has gained losses on drying, contents of ethanol-soluble extracts, contents of water-soluble extracts and contents of spicatoside A. Results : 1. Losses on drying of all group were less than 18% that is a standard of chinese pharmacopoeia. 2. Contents of ethanol-soluble extracts at LP-C, LP-D were included more than contents of those in the other groups in significance levels. 3. Contents of water-soluble extracts at LP-A, LP-C were included more than contents of those in the other groups in significance levels. 4. Contents of spicatoside A in LP-B were included more than content of spicatoside A in the other groups in significance levels. Resultingly, standards of LP in korea were proposed compatible proposals suggested as below. 1. Losses on drying of LP were less than 15% that is less than that of chinese pharmacopoeia. 2. Form to boil in water must be cutting body with heart of swelling root. 3. Because there is no content of spicatoside A in heart of swelling root, it is not suited to purpose a index component. Conclusions : The subjects of loss on drying and form of LP to boil in water must be contained in korean pharmacopoeia. Moreover, because of much valuable LP in food and medicine, it is urgently required aspect of index component such as spicatoside B, spicatoside C, flavonoid, polysaccharide having medical actions and so on.

• Geomechanics and Engineering
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• 제29권1호
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• pp.91-97
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• 2022

The cohesive non-swelling soil (CNS) cushion technology has been widely applied in the subgrade and slope improvement at expansive soil regions. However, the mechanism of the inhibition effect of the CNS layer on expansive soil (ES) has not been fully understood. We performed four outdoor model tests to further understand the inhibition effect, including different kinds of upper layer and thickness, under the unidirectional seepage condition. The swelling deformation, soil pressure, and electrical resistivity were constantly monitored during the saturation process. It is found that when a CNS layer covered the ES layer, the swelling deformation and electrical resistivity of the ES layer decreased significantly, especially the upper part. The inhibition effect of the CNS layer increases with the increase of CNS thickness. The distribution of vertical and lateral soil pressure also changed with the covering of a CNS layer. The electrical resistivity can be an effective index to describe the swelling deformation of ES layer and analyze the inhibition effect of the CNS layer. Overall, the CNS deadweight and the ion migration are the major factors that inhibit the swelling deformation of expansive soil.