• Tunnel and Underground Space
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• v.8 no.4
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• pp.287-295
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• 1998

Limit equilibrium method is widely used for the stability analysis of soil slopes. In jointed rock slopes however, the failure of the slope is largely dependent upon the strength and deformability of the joints in the rock mass and quite often failure occurs along the joints. This paper describes the use of ubiquitous joint model for the stability analysis of the jointed rock slopes. This model is essentially an anisotropic elasto-plastic model and can simulate two sets of joint in arbitrary orientations. Validation of the developed with the factor of safety equal to unity was selected when the shape of the failure plane is assumed log spiral. Then the factor of safety of the rock slope having two perpendicular joint sets was calculated while rotating joint orientations. Rusults were compared with limit equilibrium solutions on soil slopes having equivalent soil properties when plane sliding was assumed. Developed model predicted the factor of safety of jointed rock slope in a reasonable accuracy when joint spacing is sufficiently small.

• Journal of Forest and Environmental Science
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• v.9 no.1
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• pp.10-18
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• 1993

The study was carried out to investigate the physical (Density, Percentage of latewood, Percentage of pore zone, Mean annual ring width) and mechanical (Compressive strength parallel to the grain, Compression perpendicular to the grain, Shearing strength) properties of some major northern softwoods and hardwoods. The physical and mechanical properties of each species are summerized as Table 2 and the relationship between physical and mechanical factors are discussed. The results of this study were as follows: Density and percentage of latewood are closely related to physical and mechanical properties, but percentage of pore zone and mean annual ring width are remotely related to physical and mechanical properties.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.4012-4017
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• 2010

In this study, a series of triaxial compression tests(CU) were performed with artificially remolded sand-pack-clay and sand-clay composite soils at 10% and 20% replacement ratio to compare the shear strength and behavior characteristics between sand compaction pile and pack pile. From the test results, the shear strength of the pack pile is much higher than the that of the sand compaction pile.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.387-390
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• 2006

Conventional spinning, shear forming and flow forming techniques are being utilized increasingly due to the great flexibility provided for producing complicated parts, enabling customers to optimize designs and reduce weight and cost, all of which are vital, especially in automotive industries, space shuttle, a munitions industry. The deformation mechanism of conventional spinning and shear forming is studied in this paper through analysis. The forming loads of a spin formed dome in an Al launch vehicle fuel tank was studied analysis and a simple FE model to predict the forming loads of the dome was proposed. The analysis is carried out to study the effects of feed rates and thickness reduction on material flow.

• Journal of the Korean Geotechnical Society
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• v.19 no.5
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• pp.163-173
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• 2003

In this paper, a numerical comparison of predictions by limit equilibrium analysis and 3D analysis is presented for slope/pile system. Special attention is given to the coupled analysis based on the explicit finite difference code, FLAC 3D. To this end, an internal routine (FISH) was developed to calculate a factor of safety for a file reinforced slope according to shear strength reduction technique. The case of coupled analyses was performed for stabilizing piles in slope in which the pile response and slope stability are considered simultaneously. In this study, by using these methods, the failure surfaces and factors of safety were compared and analyzed in several cases, such as toe, middle and top of the slope, respectively. Furthermore, the coupled method based on shear strength reduction technique was verified by the comparison with other analysis results.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.9
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• pp.761-770
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• 2007

In this study, a swirl generator using delta wing was developed in order to simulate total pressure distortion and flow angle distortion. The delta wing was used for $65^{\circ}$-degree sweep back angle to satisfy the design performance for vortex core position, total pressure distortion(DC90) and swirl angle. To extend the swirling flow area, a $45^{\circ}$-degree vortex flap have applied to the delta wing. The swirl generator satisfied the design requirement of distortion coefficient in the flow distortion test to be applied to the simulation duct, and the performances of distortion for vortex core position and swirl angle using CFD(computational fluid dynamics) analysis results that was verified by flow distortion test results.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2008.09a
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• pp.77-89
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• 2008

본 연구는 유기흑염소 생산에 기초적인 자료를 얻고자 유형이 다른 산지 초지에 방목하여 흑염소의 발육과 육질에 미치는 영향을 조사하였다. 공시축은 흑염소 40두를 4처리구(개량목초구, 유기목초구, 산야초구, 수엽류구)로 나누어 처리구당 10두씩 공시하여 2007년 5월 15일부터 2007년 11월 5일까지 174일간 농촌진흥청 축산과학원 가축유전자원시험장 방목지에서 수행하였다. 그 결과는 다음과 같다. 일당증체량은 개량목초구가 다른 시험구 보다 유의하게 높았다(p<0.05). 도체율은 개량목초구와 유기목초구가 산야초구와 수엽류구 보다 유의하게 높게 나타났다(p<0.05). 정육율은 개량목초구가 유의하게 높게 나타났다(p<0.05). 흑염소 고기의 조지방은 산야초구가 높은 경향이었다. 고기의 리놀레산과 리놀렌산은 개량목초구 보다 유기목초구, 산야초 및 수엽류구가 높은 경향이었으며, 아라키돈산은 산야초와 수엽류구가 다른 시험구 보다 높은 경향으로 나타났다. 전단력은 산야초구가 낮은 경향이었으며, 관능검사 결과 중 다즙성과 연도는 유기목초구와 산야초구가, 풍미는 산야초구와 수엽류구가 우수한 경향으로 나타났다. 이상의 결과를 종합해 보면, 산지에 방목 사육된 유기흑염소는 다소 생산성과 도체특성은 낮으나 육질 및 물리적 특성이 우수한 경향으로 나타나 고품질 유기축산물 생산으로 농가소득 증대뿐만이 아니라 소비자 요구충족에도 가능성이 높은 것으로 기대된다.

• Journal of environmental and Sanitary engineering
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• v.12 no.1
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• pp.59-68
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• 1997

The main purpose of this study was to determine effects of BS-SBR compared with SBR on the removal of soluble organics and sludge separation. In the BS-SBR process, soluble organics were removed by suspended activated sludge as well as biological fixed films and these two processes occurred simultaneously in one tank. The removal efficiency of soluble COD in the BS-SBR, approximately 97% in both 1 and 3-cycle/d was higher than for SBR. The BS-SBR process was very efficient for SS removal. The averaged SS concentration were 4.8 mg/l over the operation period, the daily SS values were consistently below 10 mg/l in both of 1-cycle and 3-cycle a day. The sludge settling characteristics in BS-SBR were totally different from SBR's. The sludge, dark brown, was well flocculated and its floc size was visible larger than the SBR's.

• Journal of the Korean Geotechnical Society
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• v.17 no.5
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• pp.137-145
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• 2001

지오텍스타일 튜브공법은 준설토, 준설모래, 오염토사 등을 수리학적 채움을 통하여 해양구조물이나 수리학적 구조물을 축조하는 공법이다. 본 연구에서는 지오튜브공법의 국내적용을 위하여, 미국공병단의 최소 요구사항을 바탕으로 지오텍스타일을 선정하여 다양한 실내시험과 현장 적용성 시험을 실시하였다. 실내시험은 지오텍스타일과 토사간의 접촉마찰특성 분석을 위하여 대형직접전단시험을 실시하였으며, 해양구조물 설치시 파도와 조수의 영향으로 인한 토사유출량 분석을 위한 유실율시험을 실시하였다. 또한, 오염토사를 채움토사로 적용할 경우에 장.단기 환경적 영향에 대한 환경시험을 실시하였다. 현장시험은 실내모형시험을 바탕으로 토사와 물의 슬러리 혼합비율에 따른 지오텍스타일 튜브 채움방법 및 유효높이 및 단위중량 등의 계측을 실시하였다. 각종 실내 및 현장시험결과, 채움토사입자의 유실율은 약 5.0~6.0%를 유지하였으며, 지오텍스타일의 투수계수는 $\alpha$$\times$$10^{-4}$cm/sec 이상이 되어야 하며, 물과 토사의 혼합비율은 6:4이상이 되어야 한다. 환경적 영향 분석결과, 오염토사의 적용시 국내환경기준을 만족하는 것으로 나타났다. 또한, 수리학적 펌핑 압력에 대한 지오텍스타일 튜브의 최대 유효높이는 튜브 전체높이의 약 80%의 채움이 완료되었을 시점인 것으로 판단된다.다.

• Journal of the Korean Geotechnical Society
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• v.20 no.8
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• pp.89-96
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• 2004

Many researches have been devoted to developing a model fur bridge scour analysis which can consider both of the erosive potential of flowing water and the relative ability of the soil to resist erosion. The scour rate apparatus that can quantify the erosion rate of the soil has been developed by virtue of the extensive efforts. The scour rate tests were performed on 3 types of the remolding clay samples using the scour rate apparatus. The erosion characteristics of the fine-grained soil samples according to the variation of the remolding loads are examined and the correlation between the soil properties and erosion rates is also analyzed. The results of the tests and analyses show that the soil properties, especially the dry unit weight and the shear strength of the soil have great influence on the erosion characteristics.