• 제목/요약/키워드: Suction Pressure

검색결과 686건 처리시간 0.024초

Shear strength characteristics of a compacted soil under infiltration conditions

  • Rahardjo, H.;Meilani, I.;Leong, E.C.;Rezaur, R.B.
    • Geomechanics and Engineering
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    • 제1권1호
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    • pp.35-52
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    • 2009
  • A significantly thick zone of steep slopes is commonly encountered above groundwater table and the soils within this zone are unsaturated with negative pore-water pressures (i.e., matric suction). Matric suction contributes significantly to the shear strength of soil and to the factor of safety of unsaturated slopes. However, infiltration during rainfall increases the pore-water pressure in soil resulting in a decrease in the matric suction and the shear strength of the soil. As a result, rainfall infiltration may eventually trigger a slope failure. Therefore, understanding of shear strength characteristics of saturated and unsaturated soils under shearing-infiltration (SI) conditions have direct implications in assessment of slope stability under rainfall conditions. This paper presents results from a series of consolidated drained (CD) and shearing-infiltration (SI) tests. Results show that the failure envelope obtained from the shearing-infiltration tests is independent of the infiltration rate. Failure envelopes obtained from CD and SI tests appear to be similar. For practical purposes the shear strength parameters from the CD tests can be used in stability analyses of slopes under rainfall conditions. The SI tests might be performed to obtain more conservative shear strength parameters and to study the pore-water pressure changes during infiltration.

중환자실 간호사의 기관내 흡인 임상지침 수행 현황 (Adherence to Clinical Guideline for Endotracheal Suction in ICU Nurses)

  • 양은정;신현숙
    • 동서간호학연구지
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    • 제23권1호
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    • pp.53-62
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    • 2017
  • Purpose: This study aimed to evaluate the adherence to the clinical guideline for endotracheal suction in nurses working at intensive care units (ICU) and to identify the characteristics of nurses with good adherence. Methods: This study was a descriptive study to evaluate the pattern of adherence and its related factors to endotracheal suction. One hundred fifty five nurses working at ICU participated in this study. We used a questionnaire developed based on American Association for Respiratory Care (AARC) guidelines and other associated factors from previous studies. Results: Around half of the participants reported that their adherence to the clinical guideline was poor. Items deviated from the recommended guideline were reasons for initiating a suctioning, applied suction pressure ranged from 20 to 200mmHg, and applied catheter size from 6 to 17 french. Other factors deviated were the depth of inserted catheter, and inappropriate use of normal saline instillation. The most significant factor was related to hospital; the misused or misled clinical protocol. Conclusions: The adherence to the clinical guidelines of the endotracheal suction in ICU nurses was not appropriate, which might contribute to the patient health outcomes. More enhanced continuing education as well as hospital regulation is warranted.

Improving Flow Distribution in a Suction Channel for a Highly Efficient Centrifugal Compressor

  • Yagi, Manabu;Shibata, Takanori;Kobayashi, Hiromi;Tanaka, Masanori;Nishida, Hideo
    • International Journal of Fluid Machinery and Systems
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    • 제5권3호
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    • pp.100-108
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    • 2012
  • Design parameters for suction channels of process centrifugal compressors were investigated, and an optimization method to enhance stage efficiency by using the new design parameters was proposed. From results of computational fluid dynamics, the passage sectional area ratios $A_c/A_e$, $A_e/A_s$ and $A_c/A_s$ were found to be the dominant parameters for the pressure loss and circumferential flow distortion, where $A_c$, $A_e$ and $A_s$ are passage sectional areas for the casing upstream side, casing entrance and impeller eye, respectively. The Base suction channel was optimized using the new design parameters, and the Base and Optimized types were tested. Test results showed that the Optimized suction channel achieved 3.8% higher stage efficiency than the Base suction channel while maintaining the same operating range.

각질층 환경변화에 따른 얼굴과 하박내측 피부의 탄력 특성 비교연구 (Study on Skin Elasticity Property between Face and Forearm according to the Environmental Change of Stratum Corneum)

  • 장민열
    • 대한화장품학회지
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    • 제44권4호
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    • pp.455-463
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    • 2018
  • 피부의 탄성은 주로 콜라겐, 탄력섬유 등이 풍부한 진피의 영향을 받는다. 하지만, 피부의 가장 바깥층인 각질층의 변화가 피부의 기계적인 특성에 어떠한 영향을 미치는지에 대해선 아직 명확하게 밝혀지지 않고 있다. 이에 본 연구에서는 새롭게 디자인한 시험방법을 통해 피부 깊이별 탄성 특성과 수화과정을 통한 각질층 변화가 피부 탄성 특성에 어떻게 영향을 주는지를 알아보았다. 또한 이 방법을 이용해 얼굴피부와 하박내측 피부의 특성을 비교 평가하였다. 25-40세 연령의 건강한 성인 10명을 대상으로, 피부 깊이별 탄성 특성을 연구하기 위해 $Cutometer^{(R)}$의 음압을 다양하게 설정하여 얼굴피부와 하박내측 피부의 탄성 특성을 측정하여 비교 평가하였다. 음압은 100, 200, 300, 450 mbar로 구분하여 측정하였다. 또한 충분한 수화과정을 통해 각질층의 변화를 유도하고, 다양한 음압 조건에서 피부 탄성 특성을 측정하였다. 그 결과, 음압 조건을 달리함에 따라 피부 깊이에 따른 탄성 특성 측정이 가능함을 확인하였다. 그리고 하박내측 피부의 R7 값은 모든 음압조건에서 얼굴피부보다 통계적으로 유의하게 높았다(p < 0.05). 또한 수화과정에 의한 각질층의 변화는 피부탄성 특성에 영향을 줄 수 있음을 확인하였다. 특히 얼굴피부의 R7 값은 300 mbar 음압조건에서 수화전 상태의 피부에 비해 통계적으로 유의하게 변화하였다(p < 0.05). 그리고 전체적으로 얼굴피부가 하박내측 피부보다 수화과정에 더 크게 영향을 받고 있음을 알 수 있었다. 이러한 결과는 다양한 음압조건과 피부 수화 과정을 활용한다면, 각질층 및 표피층의 변화를 고려한 피부탄력특성을 평가할 수 있는 유용한 시험법이 될 것으로 사료된다.

비정상 압력측정을 통한 축류휀 유동특성에 관한 연구 (A Study on the Flow Characteristics of an Axial Flow Fan by Unsteady Pressure Measurement)

  • 강창식;신유환;김광호;이두열
    • 한국유체기계학회 논문집
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    • 제5권3호
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    • pp.15-24
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    • 2002
  • This paper presents an experimental study on the unsteady flow phenomena such as leakage flow and rotating stall which have influences on the performance and stability of an axial flow fan. For this study, unsteady pressure were measured using high frequency pressure transducers mounted on the easing wall of rotor passage and analyzed by Double Phase-Locked Averaging Technique. As the flow rate was reduced to near stall point, the pressure difference between the pressure and the suction side of the blade was increased especially new the leading edge and the lowest pressure zone of suction side was gradually developed. From the result of unsteady pressure field on the casing wall, one period of rotating stall was divided into three zones and the flow characteristics on each zone were described in detail.

흡착식 소켓을 착용한 일측 대퇴절단환자의 소켓내부압력분포 (Socket Pressure Distribution of the Uni-Lateral Trans-Femoral Amputee with a Suction Socket)

  • 장윤희;양길태;임송학;문무성;김영호
    • 대한의용생체공학회:의공학회지
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    • 제19권4호
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    • pp.417-422
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    • 1998
  • 본 연구는 대퇴의족착용자의 정적중립상태 및 자유보행시에 단단부와 소케의 경계에 작용하는 압력 분포를 측정하였다. 정적중립상태에서는 단단부의 외측과 내측면과 후면에서 압력집중현상이 나타나고, 자유보행시는 이러한 압력집중이 보행중에 일정한 형태로 이동함을 알 수 있었다. 최대 소켓압력은 중간입각기나 발뒤축들림기에 외측, 내측 앞쪽, 후면에서 나타나고 있고, 소켓과 단단부 사이의 상태를 확인하는 방법중 하나로 소켓 압력 측정을 사용할 수가 있다.

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흡인력에 따른 불포화토의 전단강도 특성 (Characteristics of Shear Strength for an Unsaturated Soil with the Matric Suction)

  • 송창섭;최득호
    • 한국환경복원기술학회지
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    • 제10권1호
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    • pp.82-90
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    • 2007
  • In order to analyse the strength problems for an unsaturated soil, it is required to examine closely the characteristics of the parameters of shear strength which was changed with the metric suction and void ratio. To this ends, a triaxial compression test was conducted on the three samples-granular soil, cohesive soil and silty soil. The specimen was made by pressing the static pressure on the mold filled soil and was controled the void ratio with the different compaction ratio. And the test was performed by using the modified apparatus of the triaxial compression tester. The range of matric suction was 0-90 kPa.The measured results for the deviator stress and parameters of shear strength were analysed with the void ratio and the compaction ratio, and they were examined closely the characteristics of the strength for an unsaturated soil.

Experimental Investigation on Separated Flows of Axial Flow Stator and Diagonal Flow Rotor

  • Kinoue, Yoichi;Shiomi, Norimasa;Setoguchi, Toshiaki;Jin, Yingzi
    • International Journal of Fluid Machinery and Systems
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    • 제2권3호
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    • pp.223-231
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    • 2009
  • Experimental investigations were conducted for the internal flows of the axial flow stator and diagonal flow rotor. Corner separation near the hub surface and the suction surface of stator blade are mainly focused on. For the design flow rate, the values of the axial velocity and the total pressure at stator outlet decrease between near the suction surface and near the hub surface by the influence of corner wall. For the flow rate of 80-90% of the design flow rate, the corner separation of the stator between the suction surface and the hub surface is observed, which becomes widely spread for 80% of the design flow rate. At rotor outlet for 81% of the design flow rate, the low axial velocity region grows between near the suction surface of rotor and the casing surface because of the tip leakage flow of the rotor.

왕복동식 압축기 흡입머플러 설계 (Design of The Suction Muffler of a Reciprocating Compressor)

  • 이정호;안광협;이인섭
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 추계학술대회논문집B
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    • pp.337-340
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    • 2001
  • The suction muffler of a reciprocating compressor is used for reducing noise produced by pressure pulsations. According to the shape, the suction muffler is classified into one-chamber type, two-chamber type, Helmholtz resonator type, pipe-resonator type, and so on. These mufflers are used according to the characteristics of the frequency of compressor noise. In this study, four pole parameters have been used for calculating Transmission Loss of the muffler, and Insertion Loss has been acquired for the optimum design of the muffler by the experiment.

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불포화토에서 공극비의 추정 (The Prediction of Void Ratio in Unsaturated Soils)

  • 이달원
    • 한국농공학회논문집
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    • 제48권4호
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    • pp.51-57
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    • 2006
  • This study was carried out to investigate the soil water characteristic curve and prediction of void ratio with net stress and matric suction using the linear elastic and volumetric deformation analysis method on unsaturated silty. The unsaturated soil tests were conducted using a modified oedometer cell and specimens were prepared at water content 2 times of liquid limit and required void ratio. The axis translation technique was used to create the desired matric suctions in the samples. It is shown that soil water characteristic curve and volumetric water content were affected significantly by preconsolidation pressure. As a matric suction increases, the reduction ratio of void ratio was shown to considerably small. Also, the predicted and measured void ratio for unsaturated soils using the linear elastic and volumetric deformation analysis showed good agreement as net stress and matric suction increases.