• 한국의류학회지
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• 제34권12호
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• pp.2062-2072
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• 2010

This research evaluates the change of the water absorbency and drying speed of a quick-drying knit fabric by repeated laundering and laundering conditions and investigates the influence of laundering conditions on the functional properties of the knit fabric. Four factors of laundering conditions were studied: detergent, water hardness, water temperature, and frequency of rotation. Knit fabrics were washed for 25 laundering cycles in a drum-type washing machine with nine different laundering conditions derived from an orthogonal array. The properties of knit fabrics were measured with a drop absorption test, a strip test, and a drying time test. Relaxation shrinkage pointed to a change in the structural characteristics of the knit fabric. Wetting time was faster and wickability was greater in the knit fabrics that underwent 5 laundering cycles; in addition, there were no obvious changes in wetting time and wickability. The detergent was the most important factor in wetting time (40.4%) and wickability (60% or above). Water hardness, water temperature and RPM had less of an effect on wetting time and wickability. There were no significant differences between the levels of laundering conditions (except for detergent) on wetting time and wickability. Drying times with neutral and alkali were slower by repeated laundering; however, there was no obvious change in drying time. Hardness, water temperature and RPM had less of an impact on drying time.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1268-1277
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• 2008

Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in about 400km section at 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. This wetting collapse problem for the compressibility of compacted sands, gravels and rockfills, has been recognized by several researchers. For this wetting settlement problem, we showed the test results carried out with 4 fill materials. These tests were performed under the condition that the fill materials were inundated at the first wetting. Subsequently, in this study, we investigated the long-term settlement characteristics of the fill materials under the repeated partial wetting and rising of the ground water table happend by rainfall.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.838-841
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• 2004

This paper presents the experimental results on the penetration of chloride. ions to ordinary portland cement concrete which is subjected to 2 different artificial environments; consecutive digestion, wetting at $3\%$ NaCl for 1 day and then drying at $40^{\circ}C$ oven for 4 days. The water-cement ratio was $35\%,\;45\%,\;55\%$. Test results showed that the intrusion depth and concentration of chloride ions penetrated into concrete in repeated wetting-drying environments were respectively deeper and higher than those of consecutive digestion environment. The penetration of chloride ions deeply depend on the effect of water to cement ratio.

• 물과 미래
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• 제21권2호
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• pp.193-201
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• 1988

토양수분 특성함수의 고차 scanning 커브에 대한 간략한 모델을 개발하였다. Mualem의 개념적 이력모델을 고차 scanning 커브에 대하여 간략하게 변형시켰다. 즉, 고차 건조곡선에 대하여는 마지막 회향점을 연직하향으로 이동시켜 주습윤곡선과 만나는 점을 회향점으로 하는 일차건조곡선으로 간주하였다. 또, 고차 습윤곡선에 대하여는 마지막 회향점을 지나는 가상의 주건조곡선에서 출발하는 일차습윤곡선으로 간주하였다. 이 간략한 모델을 사용하여 이차 scanning 커브에 대하여 계산한 토양 함수량과 Mualem의 모델을 이용해서 구한 토양 함수량을 비교하였다. 그 결과 두 모델 사이의 절대오차는 비교적 작았으며, 간략한 모델이 Mualem 모델보다 고차 건조시에는 항상 낮게, 고차 습윤시에는 항상 높게 함수량을 추정하였다. 따라서 건조와 습윤을 반복하는 경우 오차는 서로 상쇄된다. 본 연구에서 개발된 간략한 모델이 고차 scanning 커브에서의 토양 함수량을 잘 추정하였으며 계산과정을 많이 감소시켰다.

• KSTLE International Journal
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• 제9권1_2호
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• pp.22-25
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• 2008

This paper investigated the wetting and adhesion property of undulated DLC film with surface morphology controlled for a reduced real area of contact. The undulated DLC Films were prepared by 13.56 MHZ radio frequency plasma enhanced chemical vapor deposition (r.f. PECVD) by using nanoscale Cu dots surface on a Si (100) substrate. FE-SEM, AFM analysis showed that the after repeated deposition and plasma induced damage with Ar ions, the surface was nanoscale undulated. This phenomenon changed the surface morphology of DLC surface. Raman spectra of film with changed morphology revealed that the plasma induced damage with Ar ions significantly suppressed the graphitization of DLC structure. Also, it was observed that while the untreated flat DLC surfaces had wetting angle starting ranged from $72^{\circ}$ and adhesion force of 333ni. Had wetting angle the undulated DLC surfaces, which resemble the surface morphology of a cylindrical shape, increased up to $104^{\circ}$ and adhesion force decreased down to 11 nN. The measurements agree with Hertz and JKR models. The surface undulation was affected mainly by several factors: the surface morphology affinity to cylindrical shape, reduction of the real area of contact and air pockets trapped in cylindrical asperities of the surface.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.1203-1206
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• 2001

The main intent of this research is to determine the feasibility of utilizing bottom ash as CLSM(Controlled Low-strength Materials). The durability tests including permeability, repeated wetting and drying, freezing and thawing for bottom ash CLSM were conducted. Laboratory test results indicated that CLSM using bottom ash has acceptable durability performance.

• 한국지반환경공학회 논문집
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• 제15권10호
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• pp.29-34
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• 2014

본 연구에서는 다공성 실리카를 사용하여 시멘트계 고화재의 유해성을 개선한 경화토의 기후변화에 대한 강도특성을 규명하기 위하여 습윤건조 반복시험을 수행하여 경화토가 기후영향을 받기 전과 후의 강도특성을 규명하고자 한다. 본 연구에 사용된 경화토는 주위에서 쉽게 구할 수 있는 화강풍화토 및 우드칩을 사용하였으며, 일축압축시험을 위한 공시체는 지름 50 mm, 높이 100 mm의 크기로 혼합토 중량대비 실리카의 혼합비율을 5 %, 10 %, 15 %로 변화시키고 각 단계별로 우드칩을 0.5 %, 1.0 %, 1.5 % 혼합하여 제작하고 7, 14, 28일 동안 상온으로 양생시킨 후 습윤건조 반복과정을 0, 3, 6, 12 cycle을 반복하여 역학적인 특성을 평가하였다. 또한 습윤건조 전후의 상대동탄성계수 변화를 평가하기 위하여 각 사이클이 종료되면 동탄성시험을 수행하였다.

• 한국지반공학회논문집
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• 제25권8호
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• pp.95-106
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• 2009

본 연구에서는 암석과 흙이 혼합된 성토재료를 대상으로 다짐 시 함수조건 및 입도조건 등에 따라 Wetting이 성토제체의 장기압축침하에 미치는 영향을 중심으로 검토하였다. 그 결과 완전 침수를 모사한 경우 침하량이 상대적으로 매우 크게 나타났으며, 강우침투와 같이 반복적인 함수비의 증가 시에도 반복적인 침하가 관측되었다. 반면 습윤상태에서 다져진 시료나 세립분이 없는 재료의 경우에는 Wetting에 의한 침하량이 상대적으로 적게 발생되는 것을 확인할 수 있었다. 또한 동결 융해가 반복되는 경우 입자파쇄의 가속화로 압축침하가 지속적으로 발생되고 있는 것을 확인할 수 있었다. 결론적으로 이와 같은 재료에서의 장기적인 성토체 압축침하거동에는 크리프의 영향보다 함수비 증가나 반복적인 동결융해 조건이 더 큰 영향을 미치고 있는 것으로 나타났다.

• 한국염색가공학회지
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• 제10권1호
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• pp.33-37
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• 1998

It is rather important in the water and oil repellent finishing for wool fabric what kind of water-repellent agents will be used. In many cases, Fluorocarbon-based water-repellent agents(eg.Oleophobol-S), the surface tensions of which very low, were recom-mended on account of good water and oil repellencies. In repellent finishing, fabrics were padded in a bath which contained aqueous solution of water-repellent agents, and wetting agents, followed by drying and curing. The most suitable treating condition for excellent repellency was as follows Fabrics were padded at liquor pick-up ratio of 50%, with aqueous solution which contained $30g/\ell$ of water-repellent agents, and $40g/\ell$ of wetting agents. And the padded fabrics were dried at $110^\circ{C}$ for 1 minute, and cured at $160^\circ{C}$ for 2 minutes. For the fabrics, water and oil repellencies and durability to repeated dry-cleanings are observed.

• 한국전산구조공학회논문집
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• 제22권6호
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• pp.607-615
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• 2009

본 논문에서는 염소이온의 확산과 이송해석이 가능한 유한요소해석 프로그램을 개발하였으며, 해양 간만대의 건습 반복 조건을 고려하여 염소이온 침투해석을 수행하였다. 염소이온 침투에 영향을 미치는 열과 수분의 전달을 동시에 고려하였으며, 특히 염소이온 이송을 생성항 또는 소멸항으로 처리하여 온도, 상대습도, 염소이온농도를 순차적으로 풀 수 있도록 하였다. 건습 반복 주기를 변수로 한 유한요소해석 결과와 ACI Life-365방법에 의한 침투 프로파일의 비교를 통하여, Life-365 방법은 해중에서의 염소이온 침투에 대해서는 정확한 결과를 주지만 간만대의 해석결과는 건습 주기의 영향을 고려하지 못하는 것을 확인하였다. 실제 해양 콘크리트는 다양한 건습 주기의 간만대 환경에 노출되어 있으므로, 정밀한 염소 이온 침투해석을 위해서는 확산-이송 해석을 수행해야 할 것으로 생각된다.