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  • Title/Summary/Keyword: flow induction

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Evaluations on Salivary Flow Induction and Dissolution Patterns in Saliva of Pilocarpine Chewing Tablet in Healthy Human Volunteers (건강한 성인 지원자를 대상으로 한 필로칼핀 저작정의 타액분비 유도 및 타액중 용출패턴 평가)

  • Park, Kyoung-Ho
    • Journal of Pharmaceutical Investigation
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    • v.27 no.4
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    • pp.331-335
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    • 1997
  • Xerostomia is caused by organic or functional changes affecting the salivary system at different levels. Patients suffering from xerostomia may also complain of an oral burning sensation, ulceration or soreness, difficulty in swallowing, and poor denture retention. And pilocarpine is administered orally to induce salivary secretion. In Seoul National University Hospital(SNUH) pharmacy, the pilocarpine chewing tablets are prepared and supplied to patients of xerostomia in request of the dental hospital in SNUH. And we tested the salivary flow induction and the dissolution patterns of these products in saliva by a double-blind, sequential cross-over trials to eight healthy human volunteers with placebo. The pilocarpine chewing tablet contained 5 mg of pilocarpine, and placebo consisted of same materials as test drug, but didn't contain pilocarpine. In vivo experiment, all subjects were instructed to chew as 60-80 times/min. Mixed saliva was collected in the ranges of intervals such as 0-2, 2-5, 5-10, 10-15, 15-20, 20-30, 30-45 and 45-60 min after pilocarpine chewing tablet or placebo administration. Saliva volume was measured in each collecting time interval, and saliva pilocarpine concentrations were determined by reversed phase HPLC. The 82.5 percent (4.13±0.69mg) of pilocarpine was extracted from chewing tablets during mastication of 60-80 times per minute for 60 minutes. Among these dissolved amounts, 90 percent was extracted within 20 minutes. The salivary flow rates were more increased in a group who administered pilocarpine chewing tablet at the interval of 5-10, 10-15, 20-30 and 45-60 min rather than a placebo-group, but only extracted amount of pilocarpine at 45-60 min interval is significanly different between two groups (p<0.05). But total amounts of saliva secreted for 1 hour in two group-pilocarpine and placebo treated- were 46.36±9.72mland39.09±7.81ml, respectively, and were not significantly different between two groups.

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The Effects of EGR and EGR Induction Point on Combustion Noise of a Passenger Diesel Vehicle (승용 디젤엔진의 EGR과 Induction위치에 따른 소음 영향)

  • Kang, Sang-Kyu;Kim, Jae-Heon;Baek, Sung-Nam;Kang, Koo-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2007.11a
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    • pp.393-396
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    • 2007
  • EGR is well established and efficient means to reduce NOx emissions. The increase of EGR rate affects the ignition delay of the combustion due to the lower oxygen availability. The increasing of the ignition delay period causes large combustion noise. In this study, the effects of EGR and Induction Point on combustion noise are investigated by measuring cylinder pressure and noise. As a result, The Combustion noise is markedly increased under the application of EGR. The increased premixed distance by displacing EGR Induction point in flow direction causes the uniform EGR distribution and the modulation level of the combustion noise is reduced slightly.

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Design of Premium Efficiency Level of single-Phase Induction Motor using Parameter Analysis (파라미터 해석을 통한 프리미엄급 단상 유도기 효율 설계)

  • Jang, Kwang-Yong;Kim, Kwang-Soo;Lee, Joong-Woo;Jang, Ik-Sang;Kim, Sol;Lee, Ju
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.672_673
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    • 2009
  • In this paper seeks the parameter which relates with the efficiency from premium efficiency level single-phase induction motor. Also it compares with the parameters and it analyzes and an optimum parameter it seeks by FEM. Consquently, a optimal design is accomplished from the this paper. Also parameters compare efficiency. And it analyzes and studies about optimum parameter by FEM. The sample single-phase induction motor selection selected existing premium level motor. We analyze each parameter using 2-D finite element analysis (FEM). According to Study of losses and Design flow, losses and efficiency can be explain by many parameter. So this paper present optimal parameters. Finally, this paper presents the method which raises the efficiency of premium efficiency level single-phase induction motor.

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Sub-Synchronous Range of Operation for a Wind Driven Double-Fed Induction Generator

  • Saleh, Mahmoud Abdel Halim;Eskander, Mona Naguib
    • Journal of Power Electronics
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    • v.10 no.1
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    • pp.72-78
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    • 2010
  • In this paper the operation of a double-fed wound-rotor induction machine, coupled to a wind turbine, as a generator at sub-synchronous speeds is investigated. A novel approach is used in the analysis, namely, the rotor power flow approach. The conditions necessary for operating the machine as a double-fed induction generator (DFIG) are deduced. Formulae describing the factors affecting the range of sub-synchronous speeds within which generation occurs are deduced. The variations in the magnitude and phase angle of the voltage injected to the rotor circuit as the speed of the machine changes to achieve generation at the widest possible sub-synchronous speed range is presented. Also, the effect of the rotor parameters on the generation range is presented. The analysis proved that the generation range could increase from sub-synchronous to super-synchronous speeds, which increases the amount of energy captured by the wind energy conversion system (WECS) as result of utilizing the power available in the wind at low wind speeds.

A Computational Fluid Dynamics Analysis on an Electrohydrodynamics Induction Micropump (전기수력학적 유도 마이크로 펌프에 대한 전산유체역학 해석)

  • Lee, Byoung-Seo;Lee, Joon-Sik
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1851-1856
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    • 2008
  • A numerical program based on computational fluid dynamics has been developed to simulate characteristics of an EHD induction micropump. The ambiguity of boundary conditions was removed by adopting an equation formulated for electric potential as the dependent variable. The calculations show that the dependency of frequency agrees well with the experiments and the previous analysis. The instability, caused by backflows, is getting stronger as the channel depth increases, which is consistent with experiments. The present study reveals that it is due to the limit in the penetration depth which the electric field can affect. Despite the disadvantage of large channel depth, there is a certain optimal depth for the maximum flow rate.

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Development of Load Modeling for Induction Motor Using Steady-slate Equivalent Circuit (정태 등가회로해석에 의한 유도전동기 부하모델의 개발)

  • 심건보;오기봉
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.1
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    • pp.50-57
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    • 2002
  • A substantial portion of power system load is made of large induction motors. Accordingly, static and dynamic simulation of induction motors are very important in the power flow and transient stability analysis. The purpose of this paper is to report the development of load modeling for induction motor using the steady-state equivalent circuit. A proposed simulation model of induction motor lets simulation under wide range varying voltages and frequencies be very easy and exact. This paper is presented through a case study, and its feasibility is demonstrated via simulation and experiments.

A Study on the Outside Rotor Type Induction Motor (외측회전형 유도전동기에 관한 연구)

  • 김현수;배철오;김종수
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.4
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    • pp.812-818
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    • 2003
  • This paper presents a developed outside rotor type induction motor for the fan. Nearly all of the induction motors consist of two parts, rotor and stator, and the position of rotor is generally inside of stator. However, the rotor of the developed induction motor is located outside of stator. It is believed that the outside rotor type induction motor is suitable for the fan due to its large inertia, that is, it is considered that the change of air flow rate resulting from input power or load fluctuation is reduced. In this paper, the two tests which are suitable to obtain the electrical parameters of the outside rotor type induction motor were described, then various parameters of outside rotor type induction motor were measured. These are the locked rotor test and no load test. By using these tests, it was possible to determine the parameters which are presented in the steady-state equivalent-circuit of the outside rotor type induction motor. Load test of induction motor was carried out using a dynamometer and the torque-speed curve was obtained. It is believed that the results of this paper can be used for the development of the outside rotor type induction motor.

Heat transfer enhancement of finless TEFC induction motor frame by installing guide vanes (핀이 없는 전폐형 유도전동기 프레임의 정익 설치에 의한 열전달 향상)

  • Jeon, Chang-Seong;Go, Sang-Geun;Yun, Myeong-Geun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.6
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    • pp.849-859
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    • 1998
  • The heat generated in an induction motor is mostly dissipated through the frame. The study on the heat transfer characteristics of a newly manufactured finless TEFC(Totally Enclosed Fan Cooled) induction motor showed/that it had an unsuitable structure in view of the heat transfer. The angle of the cooling air flow was very large and the ribs disturbed the air flow and partially generated the wake region on the frame. In the wake region the temperature was very high. Thus the heat transfer coefficients were lower than those of the frame with fins. Also was investigated the heat transfer characteristics of the motor frame by installing various guide vanes in the fan-side end cap. An optimum heat transfer case was found and the average heat transfer coefficient of the frame was 70% higher and the average coil temperature measured by the resistance method was 9 deg. C lower than that of the frame which had no guide vanes.

Optimization of outer core to reduce end effect of annular linear induction electromagnetic pump in prototype Generation-IV sodium-cooled fast reactor

  • Kwak, Jaesik;Kim, Hee Reyoung
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1380-1385
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    • 2020
  • An annular linear induction electromagnetic pump (ALIP) which has a developed pressure of 0.76 bar and a flow rate of 100 L/min is designed to analysis end effect which is main problem to use ALIP in thermohydraulic system of the prototype generation-IV sodium-cooled fast reactor (PGSFR). Because there is no moving part which is directly in contact with the liquid, such as the impeller of a mechanical pump, an ALIP is one of the best options for transporting sodium, considering the high temperature and reactivity of liquid sodium. For the analysis of an ALIP, some of the most important characteristics are the electromagnetic properties such as the magnetic field, current density, and the Lorentz force. These electromagnetic properties not only affect the performance of an ALIP, but they additionally influence the end effect. The end effect is caused by distortion to the electromagnetic field at both ends of an ALIP, influencing both the flow stability and developed pressure. The electromagnetic field distribution in an ALIP is analyzed in this study by solving Maxwell's equations and using numerical analysis.

Characteristics on Stand-alone Operation of a Doubly-fed Induction Generator Applied to Adjustable Speed Gas Engine Cogeneration System

  • Daido, Tetsuji;Miura, Yushi;Ise, Toshifumi;Sato, Yuki
    • Journal of Power Electronics
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    • v.13 no.5
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    • pp.841-853
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    • 2013
  • An application of doubly-fed induction generator (DFIG), which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine cogeneration system. However, the DFIG requires initial excitation for startup during a blackout because the DFIG has no excitation source. In this paper, we propose the "blackout start" as a new excitation method to generate a rated voltage at the primary side during a blackout. In addition, a stand-alone operation following a blackout has been investigated by using experimental setup with a real gas engine. Power flows in the generating set with the DFIG at the stand-alone operation have been investigated experimentally. Experimental investigation of the power flow suggests that the generating set with DFIG has optimal speed in minimizing whole system losses.