• 아시안잔디학회지
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• 제25권1호
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• pp.106-111
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• 2011

본 연구는 아메리카동애등애 사육과정에서 발생한 분변토(SFC)가 골프장의 토양개량제로서 사용가능성을 평가하기 위해 모래와 혼합비율별 물리화학성을 조사하고자 한다. 토양개량제의 혼합비율에 따라 상토의 물리화학성을 조사한 결과는 다음과 같다. SFC, compost 및 cocopeat는 pH와 EC에서 고도의 정의 상관성 (P<0.01)을 나타내어 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. SFC와 compost의 혼합에 따른 토양물리성 변화에서 가장 중요한 요인은 모세관공극으로 총공극이나 수리전도도의 변화에 영향을 미쳤다. 토양개량제의 혼합비율에 따른 토양개선효과를 비교할 때, SFC는 모세관공극, 총공극 및 수리전도도에서, compost는 모세관공극, 비모세관공극, 총공극 및 수리전도도에서, cocopeat는 모세관공극과 비모세관공극에서 고도의 상판성을 나타내었다(P<0.05). 이들 결과를 통해 토양개량제의 종류와 특성 및 혼합비율이 USGA 상토의 근권층 개량과 토양 이화학성에 영향을 미치고 있음을 알 수 있으며, 본 실험조건에서는 SFC는 상토의 공극과 수리전도도의 개선효과를 보였다.

• 한국물환경학회지
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• 제32권6호
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• pp.582-588
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• 2016

The hydrological simulation program FORTRAN (HSPF) is a comprehensive watershed model that employs the hydraulic function table (FTABLE) (depth-area-volume-flow relationship) to represent the geometric and hydraulic properties of water bodies. The hydraulic representation of the HSPF model mainly depends on the accuracy of the FTABLES. These hydraulic representations determine the response time of water quality state variables and also control the scour, deposition, and transport of sediments in the water body. In general, FTABLES are automatically generated based on reach information such as mean depth, mean width, length, and slope along with a set of standard assumptions about the geometry and hydraulics of the channel, so these FTABLES are unable to accurately describe the geometry and hydraulic behavior of rivers and reservoirs. In order to compensate the weakness of HSPF for hydraulic modeling, we generated alternate method to improve the accuracy of FTABLES for rivers, using the surveyed cross sections and rating curves. The alternative method is based on the hydraulics simulated by HEC-RAS using the surveyed cross sections and rating curves, and it could significantly improve the accuracy of FTABLES. Although the alternate FTABLE greatly improved the hydraulic accuracy of the HSPF model, it had little effect on the hydrological simulation.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.497-504
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• 1999

This study presents the physical and engineering characteristics of soil-bentonite admixed liner in I landfill. Main focus was the hydraulic conductivity of compacted soil-bentonite admixed and mechanisms governing low permeable properties of the admixed liner. Laboratory and field tests such as compaction, hydraulic conductivity, density, water content for the soil-bentonite admixed liner were carried out. Quality control criteria for the best construction of the soil-bentonite admixed liner was suggested through laboratory and field test results.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.101-104
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• 1995

This paper deals with the development of fundamental design and manufacturing technique of hydraulic valve spool by optimizing of friction welding, the development of in-process real-time weld quality evaluation technique by acoustic emission and the evaluation of the mechanical properties and the fatigue life about the bar-to-bar dissimilar friction welded hydraulic valve spool steels.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.597-604
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• 2001

In this study, the engineering characteristics of soil-bentonite mixed liner are investigated using the laboratory hydraulic conductivity and strength tests. The soil used for the liner is clayey silt in the site and the weathered granitic soil located near the waste landfill studied. Mixing ratio of the bentonite which satisfies the requirement of hydraulic conductivity is determined and the optimum mixing ratio of betonite is recommended for the landfill. After the mixed liner is constructed, the block samples of the constructed liner are obtained and the properties of interest satisfy the requirements of the liner of the landfill.

• 한국물환경학회지
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• 제28권5호
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• pp.686-692
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• 2012

This study illustrates how to design and evaluate a non-point sources management detention pond using SWMM. In particular, special attention is given to the orifice design. In SWMM, orifice properties that need to be defined include its height above the bottom of the storage unit, its type, its geometry and its hydraulic properties. Among the various characteristics of orifice, the orifice hole size which is closely related to hydraulic retention time is focused in this study. Sensitivity analysis of orifice size in annual non-point sources reduction efficiency is carried out. In addition, a methodology which can be used to design a virtual junction in SWMM has been proposed to quantify water quality improvement triggered by the detention pond installation. As a result, it is recommended that a detention outlet should be designed to be about 2 to 3 days of hydraulic retention time.

• 터널과지하공간
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• 제8권3호
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• pp.184-193
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• 1998

방사성 폐기물의 안전한 처분을 위해서는 암반의 역학적, 열적, 유체 거동 뿐 아니라 암반과 물 사이의 물리 화학적 상호작용을 이해할 필요가 있다. 또한 지질구조, 지하현지응력, 습곡, 열수작용, 마그마의 관입, 판구조 등과 같은 많은 조건을 모델링하고 예측하기 위해서는 암석의 역학적, 수리적 특성을 알아야 한다. 이 연구는 심부 암반에 폐기물 처분과 관련된 암석역학적인 사항들에 대해 연구들에 기초하고 있다. 이 논문은 변하는 온도 상태에서 암반의 역학적 수리적 거동, 암반의 열-수리-역학적 상호작용 해석과 불연속 암석의 거동 특성 등을 포함한다. 역학적 특성은 Interaken 암석역학 시험 시스템으로 측정되었으며, 수리적 특성에는 순간 증압 투수계수 측정 시스템이 사용되었다. 모든 결과에서 암석 특성은 온도 변화에 민감함을 보였다.

• 한국농공학회지
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• 제33권2호
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• pp.120-129
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• 1991

This study refers to temporal variation of physical properties of tilled soil under natural rainfalls. Field measurements of porosity, average hydraulic conductivity and average capillary pressure head on a tilled soil were conducted by soil sampler and air-entry permeameter respectively at regular intervals after tillage. Temporal variation of these physical properties were analysed by cumulative rainfall energy since tillage. Field experiment was conducted on a sandy loam soil at Suwon durging April~July in 1989. The followings are a summary of this study results ; 1. Average porosity just after tillage was 0.548cm$^3$/cm$^3$. As cumulative rainfall energy were increased in 0.1070, 0.1755, 0.3849 J/cm$^2$, average porosity were decreased in 0.506, 0.4]95, 0.468m$^3$/cm$^3$ respectively. 2. Average hydraulic conductivity just after tillage was 45.42cm/hr. As cumulative rainfall energy were increased in 0.1755, 0.2466, 0.2978, 0.3849J/cm$^2$ average hydraulic conductivity were decreased in 15.34, 13.47, 9.58, 8.65cm/hr respectively. 3. As average porosity were decreased in 0.548, 0.506, 0.495, 0.468cm$^3$/cm$^3$ average capillary pressure head were increased in 6.1, 6.7, 6.9, 7.4cm respectively. 4. It was found that temporal variation of porosity, average hydraulic conductivity on a tilled soil might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity. 5. The results of this study may be helpful to predict infiltration into a tilled soil more accurately by considering Temporal variation of physical properties of soil.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.353-354
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• 2002

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper, show that there is a sharp change in viscosity drop and moderate additive depletion. For the extension of hydraulic fluid life. it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Hydraulic oil with the viscosity index of 140 and improved thermal stability consists of group III base oil, showed the possibility of extension of fluid life.

• KSTLE International Journal
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• 제2권1호
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• pp.17-21
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• 2001

Surface treatment technologies are frequently used to improve mechanical properties of surface layers of machinery components in many practical situations. Surface hardness of piston in the oil hydraulic piston pumps is very important about wear resistance. To improve hardness, wear resistance of the oil hydraulic axial piston pump, it is needed to know the surface layer characteristics in the sliding contact parts. This paper reports an experimental study on surface treatment characteristics in the piston of the oil hydraulic axial piston pump. We investigated the surface wear of a piston between untreated and nitriding-treated surfaces. We obviously observed that the surface hardness of piston in the oil hydraulic axial piston pump plays an important role to have wear resistance and remain a longer life.