• Title/Summary/Keyword: Clearances

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Diuretic action of hoelen in the dog (복령의 이뇨작용)

  • ;;Lee, Dohn Ill;Moon, Yung Hee
    • YAKHAK HOEJI
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    • v.18 no.1
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    • pp.39-48
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    • 1974
  • Intravenously administered total water extract of Hoelen, (Pachymae fungus) in a dose of 10mg/kg and its methanol lextract, in a smaller dose than total water extract, produced significantly increase on urinary volume, sodium nad potassium excretion, and osmolar nad free water clearances. Increasing the doses produced more pronounced renal responses. Glomerular filtration rate and renal plasma flow changed littl with both extract. On the contrary, water extract from residue obtained on extraction with organic solvents exhibited no significant changes on the parameters of the renal function. In experiments, in which the total water extract was infused directly into a renal artery and urines from both ureters were collected separetely, a small dose of 0.3mg/kg/min showed no diuresis, but a large dose of 1.0mg/kg/min elicited diuretic action even on the contralateral kindneys. It is, therfore, concluded that Hoelen induces diuresis, mainly by inhibiting reabsorption of electrolytes in the renal tubules, and that the renotropic action may be mediated by some endogenous humoral substances.

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Heat Transfer Characteristics by the Right Angled Triangle Rod Array in Impinging Air Jet System (충돌공기제트시스템에서 직삼각형로드에 의한 열전달특성)

  • Kum, Sung-Min
    • Journal of ILASS-Korea
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    • v.13 no.1
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    • pp.9-15
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    • 2008
  • This experimental study was carried out to examine the heat transfer characteristics of impinging air jet on a flat plate with a set of right angled triangle rods. Each right angled triangle rod in the array was positioned normal to the flow direction and parallel to the flat plate surface. The clearances from a right angled triangle rod to flat plate surface (C=1, 2 and 4 mm) and the distance from nozzle exit to flat plate (H=100 and 500 mm) were changed for the pitch between each right angled triangle rods (P=40 mm). As a result, heat transfer shows best performance at the clearance of C=1 mm, in case clearance changed, and the average heat transfer enhancement rate increased up to 47% compared to the result of a flat plate without a right angled triangle rod.

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Numerical Study on Tip Clearance Effect on Performance Characteristics of a Centrifugal Compressor for a R134a Turbo-Chiller (R134a 터보냉동기용 원심압축기의 익단간극이 성능특성에 미치는 영향에 관한 수치해석적 연구)

  • Lee, Kyoung-Yong;Choi, Young-Seok;Park, Woon-Jean
    • 유체기계공업학회:학술대회논문집
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    • 2003.12a
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    • pp.451-456
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    • 2003
  • In this study, the overall performance and the effect of the tip leakage flow of the centrifugal compressor with the refrigerant HFC-l34a were numerically studied using CFX-TASCflow. To study the effect of a tip leakage flow, the numerical study of the overall performance of HFC-l34a centrifugal compressor with a cascade diffuser was preceded and compared with experimental result. Six different tip clearances were used to consider the influence of a tip clearance on performance. The tip leakage flow was illustrated for qualitative discussion. The results obtained in this study can be applied to the determination of the cold clearance.

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Tip Clearance Losses - A Physical Based Scaling Method

  • Pelz, Peter F.;Karstadt, Sascha
    • International Journal of Fluid Machinery and Systems
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    • v.3 no.4
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    • pp.279-284
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    • 2010
  • Tip clearance losses occur in every turbomachine. To estimate the losses in efficiency it is important to understand the mechanism of this secondary flow. Tip clearance losses are mainly caused by a spiral vortex formed on the suction side of the blade of a turbomachine, which induces a drag and also has an influence on the incident flow of the blades. In this paper a physical based scaling method is developed out of an analytical ansatz for the tip clearance losses. This scaling method is validated by measurements on an axial fan with five different tip clearances.

Experimental Study on the Aerodynamic Performance Characteristics for Various Design Factors in the Maximum Flowrate Range of a Cross-Flow Fan (관류홴의 최대유량역에서 설계인자 변화에 따른 공력성능 특성에 관한 실험적 연구)

  • Kim, J.K.
    • Journal of Power System Engineering
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    • v.9 no.3
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    • pp.44-49
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    • 2005
  • The aerodynamic performance of an indoor room air-conditioner using a cross-flow fan is strongly influenced by the various design factors of a rear-guider and a stabilizer. The purpose of this study is to investigate the effects of a rear-guider and a stabilizer on the aerodynamic performance in the maximum flowrate range of a cross-flow fan. The design factors considered in this study are a rear-guider clearance, a stabilizer cutoff clearance, and a stabilizer setup angle, respectively. Aerodynamic performances including maximum flowrate and power show the biggest magnitude distribution in the case of $45^{\circ}$, the stabilizer setup angle as well as nearly similar magnitude distribution regardless of the stabilizer cutoff clearances. Moreover, the more a rear-guider clearance increases, the more the magnitude of maximum flowrate and power increases.

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Effect of The Clearance on Core Deformation of Sandwich Plate during U-bending (U-bending 공정에서 틈새간격이 샌드위치판재의 내부구조 전단변형에 미치는 영향)

  • Seong, D.Y.;Jung, C.G.;Shim, D.S.;Yang, D.Y.;Chung, W.J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.320-323
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    • 2008
  • In this study, a macroscopic approach was carried out to gain insight into the bending mechanism of metallic sandwich plates. Shear force-punch stroke curves for various clearances were analytically derived for mild steel (CSP 1N) sandwich plates with the total thickness of 3 mm and 0.5 mm face sheets. As the clearance increases, shear force of the inner structures and sensitivity of punch stroke decrease. These data are useful to derive a criterion of judgment for core shear failure and de-bonding failure during U-bending.

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A Study on the Design of water Hydraulic Systems Based on Characteristics of Tap-Water (수압 특성 연구를 기초로 한 수압시스템의 설계에 관한 연구)

  • Yun, Young-Won;Nam, Yun-Joo;Park, Myeong-Kwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.11
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    • pp.1322-1331
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    • 2004
  • This paper presents studies on the design of water hydraulic system and components to replace oil with tap-water as the pressure transmission medium in hydraulic systems. In order to improve the performance of water hydraulic system, the thermal and hydraulic properties of tap-water are first investigated. Based on these characteristics, the design parameters, such as the clearances of the moving parts, the cross-sectional area of pipes and relative roughness, are proposed so that the performance of water hydraulic system is the same as that of oil. In addition, the operating ranges, which show the possibility of using water hydraulic system, are examined.

The Structural and Frequency Response Analysis for the Bogie of the Rubber Wheel-type AGT (고무차륜형식 경전철(AGT) 대차의 구조해석 및 주파수 응답해석)

  • 변상윤;유형선;윤성호
    • Proceedings of the KSR Conference
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    • 1999.11a
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    • pp.558-565
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    • 1999
  • Rubber wheel-type AGT has two major kinds of bogie; one is the bogie type and the other and passenger loads. This paper deals with the statics analysis for two types of bogie frame subjected to combined external forces, as well as independent ones specified in UIC 515-4. Furthermore, the dynamics analysis is performed under vibrational loading conditions so as to compare dynamic characteristics, Numerical results by using commercial packages, Ⅰ-DEAS and NASTRAN show that maximum stresses do not exceed the yielding level of material used for both bogies. From an overall viewpoint of strength, the bogie type turns out to be superior to the steering type except the case of a lateral loading. It is also observed that the steering type shows a be stiffened. It is strongly anticipated that vibrational fatigue analysis should be carried out under realistic loading conditions closely matching to situations such as running surface and lateral clearances along the guideway.

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A Study on the Environmental Effects of Compact Tower in Transmission Line (송전철탑 Compact화에 따른 전기환경 영향 연구)

  • Lee, Jung-Won;Lee, Won-Kyo;Lee, Dong-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.23 no.8
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    • pp.645-650
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    • 2010
  • The continuous increase demand for electric power leads to the additional construction of transmission facilities, but it is not easy to acquire right-of-way for transmission facilities. Therefor, there is a need for compact tower that can be built on a narrow right-of-way the compact tower with polymer insulation arm is a solution. It can be upgrading conventional 154 kV transmission line voltages to 345 kV levels. However transmission voltage is increasing, environment interference (corona noise, radio interference, etc.) will occur gradually. This environment interference is depending on the electrical clearances of tower and configuration of conductors. Therefore the analysis of the factors of environmental interference is necessary in order to upgrading transmission voltage. This paper presents the design factor of a compact tower to meet the environmental interference standard.

Effect of Glibenclamide, $K^+$ Channel Blocker, on Renal Function in Rabbit (토끼의 신장기능에 미치는 $K^+$ Channel 차단제인 Glibenclamide의 영향)

  • 고석태;나종학
    • Biomolecules & Therapeutics
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    • v.9 no.1
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    • pp.26-32
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    • 2001
  • This study was investigated about the effect of glibenclamide (GLY) which is $K^{+}$ channel blocker on renal function in rabbit, GLY, when given into the vein, produced the diuretic action accompanied with the increases of amounts of N $a^{+}$ and $K^{+}$ excreted into urine ( $E_{Na}$ , $E^{K}$), and then osmolar and negative free water clearances ( $C_{osm}$, $T^{C}$$_{H2O}$), fraction excretory rates of filtered N $a^{+}$ and $K^{+}$ ( $F_{Na}$ , $F_{K}$) and ratios of $E_{K}$ against $E_{Na}$ were augmented. Filtration fraction (FF) were reduced because renal plasma flow (RPF) were not changed but glomerular filtration rates (GFR) were diminished. GLY administered into a renal artery exhibited significant reduction of urine volume along with the decreases of GFR and RPF in only experimented kidney whereas changes of renal function was not observed in control kidney. GLY given intracerebroventricularly exhibited diuretic action along with the increase of $E_{Na}$ , $E_{K}$ and $F_{Na}$ , $F_{K}$ by small dose which was not affect on renal function when it given into the vein. Above results suggest that GLY given into the vein in rabbit produce the diuretic action by inhibition of electrolytes reabsorption in renal tubules through central function. function.n. function.ion.

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