• The Journal of Engineering Geology
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• v.18 no.4
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• pp.523-535
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• 2008

A simulated rainfall system was built, and the unsaturated characteristics were examined by execution of simulated rainfall system test and soil water characteristic curve cell test(SWCC Cell Test) under the various rainfall and slope conditions. With the results, the applicability of infiltration behavior under rainfall and soil water characteristic curve models to the unsaturated weathered granite soil was examined. At the results of comparison the volumetric water content and matric suction measured in the wetting process(under rainfall) with those in the drying process(leaving as it was) of the simulated rainfall system, the volumetric water content showed a difference of $2{\sim}5%$ and matric suction of about $3{\sim}10\;kPa$, indicating the occurrence of hysteresis. In addition, the difference was relatively larger in matric suction than in the volumetric water content, and this tells that the hysteresis behavior is larger in matric suction. When the soil water characteristic curve derived from measurements in simulated rainfall system test were compared with those from the soil water characteristic curve cell test, both methods produced soil water characteristic curves close each other in the wetting process and the drying process, but in both, there was a difference between results obtained from in the wetting process and those from in the drying process. Thus, when soil water characteristic curves are rationally applied to the design and stability analysis considering of the properties of unsaturated soil, it is considered desirable to apply the soil water characteristic curve of the wetting process to the wetting process, and that of the drying process to the drying process.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.545-553
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• 2003

To achieve good dentin bonding, we must obtain proper wet dentin surface. The purpose of this study was to compare dentin surface according to different wetness degree by AFM image as studying how to obtaining proper wet dentin surface. Intact recently extracted primary teeth were used in the study. The extracted teeth were stored in distilled water at $4^{\circ}C$ until prepared. The teeth were used to prepare 1mm thick dentin disks with exposed surfaces parallel to the occlusal surfaces. The surface of the dentin were polished with polishing disk. The sample were ultrasonically cleaned with distilled water. The sample of each group were treated by different ways. We compared dentin surface of each group by AFM image. From the experiment, the following results were obtained. 1. Acid etching in the dentin surface of primary teeth, resulted in the removal of the smear layer, which opened dentinal tubules, caused the demineralization of peritubular and intertubular dentin, and exposed a collagen-rich transition zone. 2. If the etched dentin was so dehydrated, the intertubular dentin surfaces deceased in height and the diameters of the dentinal tubules decreased slightly. 3. In the group dried with compressed air for 20 seconds at 2 cm, the dentin surfaces were too excessive dried and dehydrated. 4. In the group dried with compressed air for 3 seconds at 2 cm, dry cotton, wet cotton, microbrush and absorbent tissue paper, the dentin surfaces were properly wet.

• Water for future
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• v.40 no.8
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• pp.32-38
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• 2007

• Journal of Astronomy and Space Sciences
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• v.16 no.1
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• pp.61-68
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• 1999

The radio waves transmitted from GPS satellites is delayed by the troposphere as they propagate to Earth-based GPS receivers. The troposphere delay is usually divided into two parts, the dry delay due to the atmospheric gases and the wet delay due to the water vapor. In this study for the month of May in 1998 the GPS data from two stations(Taejon, Suwon) were used to estimate the total troposphere delay in the zenith direction by the least square method. The dry delay in the zenith direction can be evaluated by using surface pressure values at the station, then the zenith wet delay is obtained by removing the zenith dry delay from the total delay. The zenith wet delay is strongly correlated with the total precipitable water. The quality of the estimate has been assessed by comparison with radiosonde data at Osan. We found the food agreement in precipitable water of the GPS estimates and the radiosonde data. The standard deviation of the difference of the difference between the GPS and radiosonde observations was 3.68mm at Suwon.

• Horticultural Science & Technology
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• v.16 no.2
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• pp.229-232
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• 1998

This study was conducted to determine the properties of seedling plate papers currently used in commercial production, then to get basic information for manufacturing new seedling plate paper. Imported seedling plate paper had high wet tensile and burst strengths in its usage circumstances. Wet tensile strength was very high with 38.7% of dry tensile strength. Wet burst strength was also very high with 62.4% of dry burst strength. The seedling plate paper contained about 30% of synthetic fibers. It had 10 Gurley sec. in air permeability indicating effective movement of air. Seedling plate papers were' made in laboratory scale. For sufficient sizing degree, the addition of 0.5% AKD (alkylketene dimer) by weight was good enough. Additional amount of AKD more than 0.5% by weight caused strength loss even though improving sizing effect. The addition of wet strength reagent such as Finex-B 2% by weight resulted in good strength and air permeability.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.6
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• pp.37-48
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• 2020

Eight colors prescribed by the Enforcement Rules of the Road Traffic Act and the group standard were tested to secure the minimum recursive reflectance performance standards when drying and wetting. The results were calculated to be 260.8 (mcd/㎡·lux) when drying white and 154.6 (mcd/㎡·lux) when wet. Yellow was 67% compared to the white reflective performance when drying. Wet poetry was 79 % and 59 %, respectively. In the case of blue, it was 64% in the case of white versus 72% in the case of white. Wet poetry was 63 % and 72 %, respectively. The range of changes in reflective performance during wetting was higher than when drying, and the absence of glass grains was similar to the previous results. The new colors also have a standard value of more than 50% compared to the white color in red, orange, pink, light green, and green. Based on this, it was estimated that the minimum reflective performance criteria according to the color of the road markings would form the basis for the enforcement rules of the Road Traffic Act.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.95-104
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• 2006

Hysteresis is a common feature exhibited in hydraulic properties of an unsaturated soil. This study focuses on hysteresis observed in a compacted weathered granite subgrade soils based on the pressure plate laboratory tests. It was found that the Soil-Water Characteristics Curve of a soil is hysteretic and unique. The results also show that the wetting and drying curves predicted using the Fredlund and Xing model is quite close to the laboratory-measured results. For a specific matric suction, water content or coefficient of permeability on a wetting curve is always lower than those found on a drying curve.

• Journal of the Korean Geotechnical Society
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• v.28 no.4
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• pp.91-100
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• 2012

Soil-water characteristic curves (SWCCs), which represent a physical property in partially saturated soils, show the relation between volumetric water content and matric suction. The SWCCs exhibit hysteresis during wetting and drying, however experimental expressions used to describe SWCCs have generally ignored the hysteresis. In addition, the shape of SWCC may depend on the void ratio which is changed by soil skeleton deformations or hysteretic behavior under various loading conditions. Hence, it is necessary to understand, both empirically and analytically, the relationship between soil skeleton deformations and the SWCCs of various soils. The typical SWCCs experimentally have drying, wetting, and the second drying curve. The measurement of a complete set of hysteretic curves is severely time-consuming and difficult works, then the first drying curve of SWCC is generally determined to estimate the hydraulic conductivity and shear strength function of partially saturated soils. This paper presents the hydraulic-mechanical behavior of partially saturated soils (weathered soil and silty soil) for volume changes and hysteresis in SWCCs regarding the difference between the first drying and wetting curve.

• The tire
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• s.69
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• pp.12-16
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• 1977

타이어의 실노면상에서의 트랙션성능을 측정, 평가하는것은 자동차의 발진, 가속, 제동 및 시회성능의 점으로브터 중요하면 이것을 측정하기 위해서 타이어 트랙션시험차를 개발했다. 이시험차는 타이어의트랙션성능을 미끄럼율과제동, 구동계수의 관계, 횡화각과 사이드포오스계수, 어라이닝토루크의 관계로 측정되는 특장을 갖는다. 이시험차를 이용해서, 건조및 습윤아스팔트노상과 설노상에서의 트랙션성능에 대한 타이어트랫드의 기본적 페턴의영향을 측정한 결과, 다음과 같은 지견을 얻었다. (1)도로의 상태의 상위에 의한 타이어트랙션 성능은 건조상태에선 습윤상태보다 크며 노설상에선 전양자보다 훨씬 작다. (2)트랫드의 종방향의 구본수의 영향에 대해선 여하한 노면상태에서든 구본수가 증가한만큼 트랙션성능은 증가하나 어느구본수에선 포화하는 경향이 있다. (3)설노상에서의 트랫드의 구각도에 대해서는 구의각도가 타이어의 진행방향에 대해서 직각의 페턴이 좋다고 할 수 있다.

• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.93-100
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• 2022

This study describes the evaluation results on the effect of soil particle surfaces coated with various hydrophobic conditions on spectral information according to water content. Wettability test and spectral information evaluation test were performed on the hydrophobic coated standard sand. When the standard sand was coated with 1%, 3%, and 5% hydrophobic, the contact angles of sand-water interface were 130°~143°, 129°~144°, and 131°~144°, respectively. This means that the contact angle increased as the degree of hydrophobic coating increased at the same drying time, but the range of the contact angle had the same wettability. This means that the contact angle increases as the hydrophobic coating degree increases at the same drying time, whereas the contact angle range has the same wettability. As a result of spectral information evaluation, the maximum spectral reflectance of the dried sand with hydrophobic condition decreased compared to that of the hydrophilic sand, as the degree of hydrophobic increased. However, the maximum spectral reflectance was increased by increasing the degree of hydrophobic under the same water content conditions.