• 제목/요약/키워드: hydraulic volume

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Updates on the treatment of adhesive capsulitis with hydraulic distension

  • Jang Hyuk, Cho
    • Journal of Yeungnam Medical Science
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    • 제38권1호
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    • pp.19-26
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    • 2021
  • Adhesive capsulitis of the shoulder joint is a common disease characterized by pain at the insertional area of the deltoid muscle and decreased range of motion. The pathophysiological process involves fibrous inflammation of the capsule and intraarticular adhesion of synovial folds leading to capsular thickening and contracture. Regarding the multidirectional limitation of motion, a limitation in external rotation is especially prominent, which is related to not only global fibrosis but also to a localized tightness of the anterior capsule. Ultrasound and magnetic resonance imaging studies can be applied to rule out other structural lesions in the diagnosis of adhesive capsulitis. Hydraulic distension of the shoulder joint capsule provides pain relief and an immediate improvement in range of motion by directly expanding the capsule along with the infusion of steroids. However, the optimal technique for hydraulic distension is still a matter of controversy, with regards to the infusion volume and rupture of the capsule. By monitoring the real-time pressure-volume profile during hydraulic distension, the largest possible fluid volume can be infused without rupturing the capsule. The improvement in clinical outcomes is shown to be greater in capsule-preserved hydraulic distension than in capsule-ruptured distension. Moreover, repeated distension is possible, which provides additional clinical improvement. Capsule-preserved hydraulic distension with maximal volume is suggested to be an efficacious treatment option for persistent adhesive capsulitis.

필터재의 입도범위와 작용수압에 따른 성토재의 유실 특성 (Characteristics of Volume Loss for Base Materials with Different Hydraulic Pressures and Filter Grain Size)

  • 송창섭;인현식
    • 한국농공학회지
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    • 제45권3호
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    • pp.65-72
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    • 2003
  • The objective of this study is to evaluate the stability of the design criteria recommended by Betram and Terzaghi as compared with the experimental result. A series of NEF tests was conducted to determine the loss of volume in base soils. The three kinds of base soils classified as CL, SC and SM are used for the NEF tests with various hydraulic pressures and filters following upper and lower bond of the criteria. Volume loss characteristics of the base soils was examined closely by the results of the test successfully. Firstly, it was found that the loss of base soils was mostly eroded at the first stage of seepage. Secondly, the amount of loss volume was ranked CL > SM > SC in order of their amounts for upper criteria, and SM > CL > SC orderly for lower criteria. Thirdly, the volume loss of all soils was increased with increasing the hydraulic pressures. And lastly, the needs of the new design criteria was proved for the control of seepage and piping.

필터재의 수압에 따른 유실량 측정 (Determination of Loss Volume according to Hydraulic Pressure in Filter Materials)

  • 인현식;송창섭;임성윤
    • 한국농공학회:학술대회논문집
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    • 한국농공학회 2002년도 학술발표회 발표논문집
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    • pp.337-340
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    • 2002
  • The purpose of this study is to evaluate the loss volume of base soil materials with the grain size range of filter materials for agricultural reservoir. The test results show that the loss volume is increased with the hydraulic pressure, and the amount of loss volume for same sample is different with the filter range.

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압력실의 크기와 운전 조건에 따른 수격펌프의 성능에 대한 실험적 고찰 (Experimental Study on the Effect of Air Chamber Size and Operation Parameters on the Performance of a Hydraulic Ram Pump)

  • 은골 에농진 에봉 죠오지;홍성구
    • 한국농공학회논문집
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    • 제61권4호
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    • pp.55-61
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    • 2019
  • Motor pumps cannot be used in those areas where electricity is not accessible such as remote rural areas in many African countries. Hydraulic ram pump is one of the solutions for supplying water for irrigation or domestic uses. The hydraulic ram pumps are working based on the water hammer effect for pumping without external power or electricity. This study was conducted to investigate the effect of air chamber volume and operation parameters on the performance of the hydraulic ram pump which was assembled with common plumbing parts. The experimental results showed the volume of the air chamber did not affect the performance such as discharge rate and head. When drive heights were 1.7 and 2.35 m, the maximum discharge heads were up to 7 m and 10 m, respectively. When the air chamber volume was 1 L, discharge rates were 0.23 and 2.12 L/min under the drive heights of 1.7 and 2.35 m, respectively. The average energy efficiency of the hydraulic ram pump assembled in this study was about 60% for all the experimental conditions.

MODELING THE HYDRAULIC CHARACTERISTICS OF A FRACTURED ROCK MASS WITH CORRELATED FRACTURE LENGTH AND APERTURE: APPLICATION IN THE UNDERGROUND RESEARCH TUNNEL AT KAERI

  • Bang, Sang-Hyuk;Jeon, Seok-Won;Kwon, Sang-Ki
    • Nuclear Engineering and Technology
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    • 제44권6호
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    • pp.639-652
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    • 2012
  • A three-dimensional discrete fracture network model was developed in order to simulate the hydraulic characteristics of a granitic rock mass at Korea Atomic Energy Research Institute (KAERI) Underground Research Tunnel (KURT). The model used a three-dimensional discrete fracture network (DFN), assuming a correlation between the length and aperture of the fractures, and a trapezoid flow path in the fractures. These assumptions that previous studies have not considered could make the developed model more practical and reasonable. The geologic and hydraulic data of the fractures were obtained in the rock mass at the KURT. Then, these data were applied to the developed fracture discrete network model. The model was applied in estimating the representative elementary volume (REV), the equivalent hydraulic conductivity tensors, and the amount of groundwater inflow into the tunnel. The developed discrete fracture network model can determine the REV size for the rock mass with respect to the hydraulic behavior and estimate the groundwater flow into the tunnel at the KURT. Therefore, the assumptions that the fracture length is correlated to the fracture aperture and the flow in a fracture occurs in a trapezoid shape appear to be effective in the DFN analysis used to estimate the hydraulic behavior of the fractured rock mass.

Hydraulic fracture simulation of concrete using the SBFEM-FVM model

  • Zhang, Peng;Du, Chengbin;Zhao, Wenhu;Zhang, Deheng
    • Structural Engineering and Mechanics
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    • 제80권5호
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    • pp.553-562
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    • 2021
  • In this paper, a hybrid scaled boundary finite element and finite volume method (SBFEM-FVM) is proposed for simulating hydraulic-fracture propagation in brittle concrete materials. As a semi-analytical method, the scaled boundary finite element method is introduced for modelling concrete crack propagation under both an external force and water pressure. The finite volume method is employed to model the water within the crack and consider the relationship between the water pressure and the crack opening distance. The cohesive crack model is used to analyse the non-linear fracture process zone. The numerical results are compared with experimental data, indicating that the F-CMOD curves and water pressure changes under different loading conditions are approximately the same. Different types of water pressure distributions are also studied with the proposed coupled model, and the results show that the internal water pressure distribution has an important influence on crack propagation.

A New Approach in Numerical Assessment of the Cavitation Behaviour of Centrifugal Pumps

  • Stuparu, Adrian;Susan-Resiga, Romeo;Anton, Liviu Eugen;Muntean, Sebastian
    • International Journal of Fluid Machinery and Systems
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    • 제4권1호
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    • pp.104-113
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    • 2011
  • The paper presents a new method for the analysis of the cavitation behaviour of hydraulic turbomachines. This new method allows determining the coefficient of the cavitation inception and the cavitation sensitivity of the turbomachines. We apply this method to study the cavitation behaviour of a large storage pump. By plotting in semi-logarithmic coordinates the vapour volume versus the cavitation coefficient, we show that all numerical data collapse in an exponential manner. By analysis of the slope of the curve describing the evolution of the vapour volume against the cavitation coefficient we determine the cavitation sensitivity of the pump for each operating point.

경상분지 백악기 화강암 암반에 대한 삼차원 수리전도텐서 추정사례 (Estimation of 3-D Hydraulic Conductivity Tensor for a Cretaceous Granitic Rock Mass: A Case Study of the Gyeongsang Basin, Korea)

  • 엄정기;이다혜
    • 지질공학
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    • 제32권1호
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    • pp.41-57
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    • 2022
  • 본 연구는 부산 기장지역에 분포하는 백악기 흑운모 화강암에 대한 사례연구를 통하여 DFN(discrete fracture network) 유동해석 기반의 REV(representative elementary volume) 크기 및 삼차원 수리전도텐서 추정을 위한 워크플로우를 제시하였다. 연구지역을 대표하는 이차원 DFN에 대하여 절리텐서의 일차불변량을 이용하여 절리의 빈도 및 길이가 보정되었다. 현장수압시험을 수행하여 선형의 등가유로관으로 취급된 현장의 절리에 대한 유효수리간극이 추정되었다. 연구지역의 이차원 DFN 블록에 대한 REV의 크기는 블록 크기에 따른 지향적 블록수리전도도의 변화를 분석하여 20 m × 20 m으로 결정하였다. 연구지역의 이차원 DFN에 대하여 산정된 지향적 블록수리전도도는 현장의 수리적 거동과 관련하여 강한 이방성을 지시한다. 다양한 방향으로의 이차원 DFN에서 산정된 지향적 블록수리전도도를 바탕으로 연구지역의 절리성 암반에 대한 삼차원 수리전도텐서가 추정되었다. 삼차원 수리전도텐서의 주성분 방향은 현장에서 구분된 주 절리군의 방향과 일치한다.

시공조건이 시멘트계 고화토의 투수계수에 미치는 영향 (Effects of Some Construction Variables on the Hydraulic Conductivity of Soil-Cement in Low Permeable Applications)

  • 정문경;김강석;우제윤
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 가을 학술발표회 논문집
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    • pp.427-434
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    • 2000
  • Hydraulic conductivity of soil-cement was measured as a function of some selected construction variables that are often encountered in practice. They are initial (or compaction) water content, delayed compaction after mixing, and repeated freezing and thawing. Sandy and clayey soils were used. The hardening agent used was a cement based soil stabilizer consisting of 80% of ordinary Portland cement and 20% of a combination of supplementary materials. Hydraulic conductivity of soil-cement with varying initial water content was, in trend, similar to that of compacted clay. Hydraulic conductivity of soil-cement decreased with increasing initial water content and reached its minimum when compacted wet of optimum water content. Pore size distributions of soil cement at different initial water contents were analyzed using mercury intrusion porosimetry. The analysis showed that dryer condition led to the formation of larger pores with lesser total pore volume; smaller pores with larger total pore volume at wetter condition. Hydraulic conductivity of soil-cement increased by orders in magnitude when specimen underwent delayed compaction of longer than 4 hours after mixing and repeated freezing and thawing.

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헬름홀츠 감쇠기를 응용한 유압시스템의 유압맥동 및 소음 최소화 연구 (Hydraulic Pulsation and Noise Reduction using the Helmholtz Attenuator)

  • 김동현;이대옥;최근국
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1997년도 춘계학술대회 논문집
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    • pp.614-619
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    • 1997
  • The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

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