• Title/Summary/Keyword: High-pressure experiment

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Analysis of Inductively Coupled Plasma using Electrostatic Probe and Fluid Simulation (정전 탐침법과 유체 시뮬레이션을 이용한 유도결합 Ar 플라즈마의 특성 연구)

  • Cha, Ju-Hong;Lee, Ho-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.65 no.7
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    • pp.1211-1217
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    • 2016
  • Discharge characteristics of inductively coupled plasma were investigated by using electrostatic probe and fluid simulation. The Inductively Coupled Plasma source driven by 13.56 Mhz was prepared. The signal attenuation ratios of the electrostatic probe at first and second harmonic frequency was tuned in 13.56Mhz and 27.12Mhz respectively. Electron temperature, electron density, plasma potential, electron energy distribution function and electron energy probability function were investigated by using the electrostatic probe. Experiment results were compared with the fluid simulation results. Ar plasma fluid simulations including Navier-Stokes equations were calculated under the same experiment conditions, and the dependencies of plasma parameters on process parameters were well agreed with simulation results. Because of the reason that the more collision happens in high pressure condition, plasma potential and electron temperature got lower as the pressure was higher and the input power was higher, but Electron density was higher under the same condition. Due to the same reason, the electron energy distribution was widening as the pressure was lower. And the electron density was higher, as close to the gas inlet place. It was found that gas flow field significantly affect to spatial distribution of electron density and temperature.

The Study on Performance Characteristics in Refrigeration System using R717 and R22 as working fluid (냉매 R717과 R22를 작동유체로 이용한 냉동장치의 성능특성에 관한 연구)

  • Kim, Jin-Hyun;Kim, Jae-Geun;Kim, Jong-Gil;Kim, Yang-Hyun;Hong, Suk-Ju;Ha, Ok-Nam
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.495-500
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    • 2006
  • Nowadays HCFCs refrigerant are restricted because it cause depletion of ozone layer. However, natural gases such as ammonia as an organic compound, propane and propylene as hydrocarbon are easy and cheap to obtain as well as environmental. Accordingly, this experiment apply the $NH_3$ and R22 to study the performance characteristic from the superheat control and compare the energy efficiency of two refrigerants from the high performance. The condensing pressure of refrigeration system is increased from 15bar to 16bar and degree of superheat is increased from 0 to $10^{\circ}C$ at each condensing pressure. As the result of experiment, when comparing the each COP, we knew the $NH_3$ is suitable as the alternative refrigerant of the R22.

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The Effects of the Tai Chi Exercise on Metabolic Syndrome and Health-related Quality of Life in Middle-aged Women (타이치 운동이 중년여성의 대사증후군 위험인자 및 건강관련 삶의 질에 미치는 영향)

  • Eom, Ae-Yong
    • Journal of muscle and joint health
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    • v.19 no.2
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    • pp.152-160
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    • 2012
  • Purpose: The purpose of this study was to test the effects of the Tai Chi exercise on metabolic syndrome and health-related quality of life in middle-aged women. Methods: A quasi-experimental design was used. Subjects were sixty middle-aged women with metabolic syndrome. All of the subjects were met the criteria of the National Cholesterol Education Program-Adult Treatment Panel III (NCEP-ATP III). The subjects were divided into the experiment group (n=33) trained the Tai Chi for 12 weeks and the control group (n=27). Metabolic syndrome risk factors including blood pressure, waist circumference, glucose, triglyceride (TG), and high density lipoprotein cholesterol (HDL-C) were measured before and after the 12-week period. Euro Quality of Life Questionnaire 5-Dimensional Classification (EQ-5D) was used to evaluate the health-related quality of life. Results: The experiment group showed significant decreases in diastolic blood pressure, waist circumference, glucose, and TG; and increase in HDL-C compared to the control group. For the health-related quality of life evaluation, the experiment group showed significant improvement more than the control group. Conclusion: The Tai Chi exercise may be effective intervention in preventing cardiovascular disease caused by metabolic syndrome in middle-aged women.

An Analytic and Experimental Study on the Performance Characteristic of the Rotary Compressor (로타리 압축기 성능특성에 관한 해석 및 실험)

  • 최득관;김경천;차강욱
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.6
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    • pp.497-504
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    • 2001
  • A study to improve the accuracy of a map-based compressor model with experiment was performed. Corrections on the effects of suction gas superheat and heat leakage from a compressor shell are required to apply the compressor amp model based on the empirical performance data(map) of compressor manufacturers to the actual system. So experiments to assess the effects of superheat and hat leakage were performed and the corrected equations were made. Compressors and refrigerant used in the experiment were the high pressure type rotary compressor and R-22, experiments were performed by compressor calorimeter. From the experiment, a volumetric efficiency correction factor$(F_ν)$ showed the value of 0.77, slightly higher than 0.75 proposed by Dabiri and Rice for low pressure type reciprocating compressor, and the heat leakage from the compressor shell turned out to be a factor that influenced the discharged mass flow rate. The relation between heat leakage of compressor shell and the variation of discharged mass flow rate from compressor was considered in compressor map modeling as an empirical function. With this function, the prediction accuracy of compressor model in system conditions was improved.

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Effect of Low Pressure Fog and External Watering on the Fruit Quality of Korean Melon Grown in Sumer (여름철 참외 재배시 저압포그 및 외부살수가 과실의 품질에 미치는 영향)

  • Shin, Yong Seub;Lee, Ji Eun;Kim, Min Ki;Do, Han Woo;Park, Jong Tae
    • Journal of Bio-Environment Control
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    • v.25 no.1
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    • pp.24-29
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    • 2016
  • The objective of this study was to examine the changes in temperature drop and fruit production due to low pressure fog system in plastic greenhouses during summer cultivation of Korean melon. The indoor temperature of plastic house was dropped by $7.6^{\circ}C$ compared to control on July 26th, 2015 from 10:00 to 18:00. Fruit weight was smaller and lighter by 96g compared to control. The sugar content and color parameter were also enhanced due to application of low pressure fog system. The fraction of malformed fruits was decreased by 15.3% in plots where low pressure fog system was applied. The fraction of marketable fruit and yield were increased by 15.3% and 26% compared to control, respectively. As a result, high quality fruit production within plastic house of summer was increased by applying low pressure fog system and it is positively affected the drop of indoor temperature.

Application to Non-linear Viscoelastic Model on Capillary Extrusion of Rubber Compounds (고무복합체의 모세관 압출에서 비선형 점탄성 모델의 적용)

  • Choi, S.H.;Lyu, M.Y.;Kim, H.J.;Park, D.M.;Jun, J.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.209-212
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    • 2007
  • Rubber compounds have high viscoelastic property. One of the viscoelastic behaviors during profile extrusion is the swelling of extrudate. In this study, die swell of rubber compounds at the capillary die have been investigated through an experiment and computer simulation. They have been performed using fluidity tester in experiment and commercial CFD code, Polyflow in computer simulation. Die swell of rubber compounds for relaxation time at several modes under same conditions with the experiment were predicted using non-linear differential viscoelastic model, Phan-Thien-Tanner (PTT) model. The simulation was analyzed compared with the experiment. Viscoelastic behaviors for pressure, velocity and shear rate distribution were analyzed at the capillary die. It is concluded that the PTT model successfully represented the amount of the optimal die swell of rubber compounds for relaxation time at different modes.

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The Effect of Ground Condition, Tire Inflation Pressure and Axle Load on Steering Torque (노면상태, 타이어 공기압 및 축하중이 조향력에 미치는 영향)

  • Park W. Y.;Kim S. Y.;Lee C. H.;Choi D. M;Lee S. S.;Lee K. S.
    • Journal of Biosystems Engineering
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    • v.29 no.5 s.106
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    • pp.419-424
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    • 2004
  • In this study, a series of soil bin experiment was carried out to investigate experimentally the effect of the tire inflation pressure and axle load of tire on the steering torque for the off-road condition. The experiment was performed at the three levels of off-road conditions(ground I, ground II and ground III) and on-road condition(ground IV), four levels of tire inflation pressure(120 kPa, 170 kPa, 220 kPa and 270 kPa), and four levels of axle load(1470N, 1960N, 2450N and 2940N). The results of this study are summarized as follows: 1. Steering torque at the off-road conditions were higher than that on the on-road conditions for all levels of tire inflation pressure and axle load. 2. As the axle load increased, steering torque also increased f3r all experimental ground conditions. 3. For the axle load of 1470N the biggest steering torque was measured on the ground condition I, but as the axle load increased to the value of 2940N the biggest steering torque was measured on the ground condition III. From the above results, it was found that for the low axle load, steering torque gets higher on the soft ground condition, but for the high axle load, steering torque gets higher on hard ground condition for whole range of experimental conditions. 4. As the tire inflation pressure decreased, steering torque increased on the on-road condition, but no specific trend was not found at the off-road conditions.

A STUDY ON NUMERICAL COUPLING BETWEEN MECHANICAL AND HYDRAULIC BEHAVIORS IN A GRANITE ROCK MASS SUBJECT TO HIGH-PRESSURE INJECTION

  • Jeong, Woo-Chang;Jai-Woo;Song, Jai-Woo
    • Water Engineering Research
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    • v.2 no.2
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    • pp.123-138
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    • 2001
  • An injection experiment was carried ut to investigate the pressure domain within which hydromechanical coupling influences considerably the hydrologic behavior of a granite rock mass. The resulting database is used for testing a numerical model dedicated to the analysis of such hydromechanical interactions. These measurements were performed in an open hole section, isolated from shallower zones by a packer set at a depth of 275 m and extending down to 840 m. They consisted in a series of flow meter injection tests, at increasing injection rates. Field results showed that conductive fractures from a dynamic and interdependent network, that individual fracture zones could not be adequately modeled as independent systems, that new fluid intakes zones appeared when pore pressure exceeded the minimum principal stress magnitude in that well, and that pore pressures much larger than this minimum stress could be further supported by the circulated fractures. These characteristics give rise to the question of the influence of the morphology of the natural fracture network in a rock mass under anisotropic stress conditions on the effects of hydromechanical couplings.

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An Investigation on Spray Characteristics of Diesel - DME with Change of Injection Pressure (분사압력 변화에 따른 디젤-DME연료의 다단분사 특성에 관한연구)

  • Jeong, Y.H.;Yang, J.W.;Oh, C.H.;Lim, O.T.
    • Journal of ILASS-Korea
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    • v.18 no.4
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    • pp.188-195
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    • 2013
  • An investigation on spray characteristics of fuels which diesel and di-methyl ether (DME) with change of injection pressure used the multi-injection in constant volume combustion chamber (CVCC). Diesel was already used famous fuel which we could use. DME showed similar features with diesel like as cetane number, auto-ignition temperature. High cetane number of diesel and DME could make possible to compression ignition. DME showed different atomization from diesel due to evaporating pressures and boiling points. Experiments were carried out in CVCC equipped with Delphi solenoid 6-hole type injector and the spray characteristics of diesel and DME were tested the various pre and pilot injection. Terms of injections and a number of injections in multi-injection has been controlled. Experiments were performed in 2 types that 1500 rpm, 2000 rpm and under the condition of injection ranging from 100 bar to 500 bar. From the results of this experiment diesel showed longer spray penetration than DME. That result showed different of atomization speed DME and diesel. Result of high injection pressure condition showed similar spray characteristics diesel and DME. After this investigation, new conditions and experiments using laser light to go forward and add the fuels like as the biodiesel and diesel and DME blend.

Rapid and massive throughput analysis of a constant volume high-pressure gas injection system

  • Ren, Xiaoli;Zhai, Jia;Wang, Jihong;Ren, Ge
    • Nuclear Engineering and Technology
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    • v.51 no.3
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    • pp.908-914
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    • 2019
  • Fusion power shutdown system (FPSS) is a safety system to stop plasma in case of accidents or incidents. The gas injection system for the FPSS presented in this work is designed to research the flow development in a closed system. As the efficiency of the system is a crucial property, plenty of experiments are executed to get optimum parameters. In this system, the flow is driven by the pressure difference between a gas storage tank and a vacuum vessel with a source pressure. The idea is based on a constant volume system without extra source gases to guarantee rapid response and high throughput. Among them, valves and gas species are studied because their properties could influence the velocity of the fluid field. Then source pressures and volumes are emphasized to investigate the volume flow rate of the injection. The source pressure has a considerable effect on the injected volume. From the data, proper parameters are extracted to achieve the best performance of the FPSS. Finally, experimental results are used as a quantitative benchmark for simulations which can add our understanding of the inner gas flow in the pipeline. In generally, there is a good consistency and the obtained correlations will be applied in further study and design for the FPSS.