• Title/Summary/Keyword: Discharge coefficients

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A Study on post-hospital Home health Care Needs in a General Hospital (일 종합병원 퇴원환자의 가정간호요구조사)

  • Choi, Hwa-Young;Lee, Myung-Ha
    • Journal of Home Health Care Nursing
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    • v.9 no.2
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    • pp.138-152
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    • 2002
  • The purpose of this study is to provide a basic data of home health care nursing centered in the hospital by analyzing home health care needs. Data were collected from June 15. 2000 to June 23. 2000 through questionnaires taken by 208 patients to be discharge in a general hospital. The Home Health Care Need instruments used for collecting data was developed by the researcher. The data obtained were analyzed using frequency. percentage. mean. standard deviation. Chi-square test. t-test. one-way ANOVA. Pearson's correlation coefficients. Cronbach's alpha coefficients and Factor Analysis. The results of the study were as follows: 1. The perception of home health care nursing were 65.4% of subjects had never heard about home health care service and 2.4% of subjects knew about the methods & contents in detail. About the demands of home health care, 58.2% of the subjects were willing to use home health care and 41.8% weren't. 2. Regarding the areas of home health care needs. basic nursing care area was the highest. Education/ counselling, exercise/ hygiene. therapeutic nursing care was orderly. Injection and medication management of basic nursing care area were the highest. 3. In relation to characteristic-related diseases and home health care needs. as for the discharge type, the existence of sores, paralysis showed significant differences with home health care needs in the area of exercise/ hygiene(p<,05). Home health care needs in the area of therapeutic nursing care and exercise/ hygiene showed significant differences with the existence of pain. Home health care needs in the area of therapeutic nursing and basic nursing areas were significantly different in the use of catheter/ assistant instrument(p<.05). Home health care needs in the area of therapeutic nursing. exercise/ hygiene and basic nursing care showed significant difference with diagnosis(p<,05). In conclusion, awareness about home health care nursing were very low, home health care needs in the area of basic nursing was the highest. Home health care needs showed significant difference with discharge type, sores, paralysis, existence of pain, use of catheter/ assistant instrument and diagnosis.

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Effect of Orifice Geometry on Flow Characteristics of Liquid Jet from Single Hole Nozzle (오리피스 형상에 따른 단공노즐 액체제트의 유동특성)

  • Song, Yoonho;Hwang, Donghyun;Ahn, Kyubok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.5
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    • pp.19-28
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    • 2017
  • Effects of cavitation and hydraulic flip in circular and elliptical nozzles on the flow characteristics have been studied. Spray tests were conducted using injectors with different ratios of an orifice length(L) to a diameter(d) and of a major axis diameter(a) to a minor axis diameter(b). With the increment of an injection pressure drop, discharge coefficients slightly decreased in cavitation flows, and those suddenly dropped and were almost constant in hydraulic flip flows. For elliptical nozzles with L/b > 8 and L/a < 8, discharge coefficients and flow patterns showed different results from those in previous circular nozzles. When a flow in the elliptical nozzle was under steady condition, as the liquid column went downstream from the nozzle, its spray angle a little decreased in the plane of a major axis and increased in the plane of a minor axis.

Study on Calibration Methods of Discharge Coefficient of Sonic Nozzles using Constant Volume Flow Meter

  • Jeong, Wan-Seop;Sin, Jin-Hyeon;Gang, Sang-Baek;Park, Gyeong-Am;Im, Jong-Yeon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.08a
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    • pp.17-17
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    • 2010
  • This paper address technical issues in calibrating discharge coefficients of sonic nozzles used to measure the volume flow rate of low vacuum dry pumps. The first challenging issue comes from the technical limit that their calibration results available from the flow measurement standard laboratories do not fully cover the low vacuum measurement range although the use of sonic nozzles for precision measurement of gas flow has been well established in NMIs. The second is to make an ultra low flow sonic nozzlesufficient to measure the throughput range of 0.01 mbar-l/s. Those small-sized sonic nozzles do not only achieve the noble stability and repeatability of gas flow but also minimize effects of the fluctuation of down stream pressures for the measurement of the volume flow rate of vacuum pumps. These distinctive properties of sonic nozzles are exploited to measure the pumping speed of low vacuum dry pumps widely used in the vacuum-related academic and industrial sectors. Sonic nozzles have been standard devices for measurement of steady state gas flow, as recommended in ISO 9300. This paper introduces two small-sized sonic nozzles of diameter 0.03 mm and 0.2 mm precisely machined according to ISO 9300. The constant volume flow meter (CVFM) readily set up in the Vacuum center of KRISS was used to calibrate the discharge coefficients of the machined nozzles. The calibration results were shown to determine them within the 3% measurement uncertainty. Calibrated sonic nozzles were found to be applicable for precision measurement of steady state gas flow in the vacuum process. Both calibrated sonic nozzles are demonstrated to provide the precision measurement of the volume flow rate of the dry vacuum pump within one percent difference in reference to CVFM. Calibrated sonic nozzles are applied to a new 'in-situ and in-field' equipment designed to measure the volume flow rate of low vacuum dry pumps in the semiconductor and flat display processes.

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2D Numerical Simulations for Shallow-water Flows over a Side Weir (측면 위어를 넘나드는 천수 흐름에 대한 2차원 수치모의)

  • Hwang, Seung-Yong
    • Journal of Korea Water Resources Association
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    • v.48 no.11
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    • pp.957-967
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    • 2015
  • It was reviewed for the 2D numerical simulations to evaluate the effects of flood control by detention basin, even if stage-discharge relationships for the side weir were not known. A 2D depth-integrated numerical model was constructed by the application of the finite volume method to the shallow water equations as a numerical method and the introduction of an approximate Riemann solver for the accurate calculation of fluxes. Results by the model were compared with those by the laboratory test for the cases of free overflow and submerged flow over a side weir between the channel and storage. The difference between simulated and measured discharge coefficients for the case of free overflow is very small. In addition, the results by simulations were in good agreement with those by experiments for the submerged flow over a side weir and its mechanism was reproduced well. Through this study the discharge coefficients of side weirs can be accurately determined by the 2D numerical model and a considerable degree of accuracy can be achieved to evaluate the effect of flood defenses by detention basins. Thus, it will be expected to apply this model practically to the plan of detention basins, the evaluation of design alternatives, or the management of the existing ones.

Analysis of Electron Swarm Diffusion Coefficients and Energy Distribution Function in $e^-$-$CF_4$ Scattering ($e^-$-$CF_4$산란중에서 전자군의 확산계수 및 에너지분포함수 연구)

  • 하성철;임상원
    • Electrical & Electronic Materials
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    • v.10 no.4
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    • pp.342-348
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    • 1997
  • In this paper, the behavior of electron swarm parameters and energy distribution function of the discharge under high E/N condition in e$^{-10}$ -CF$_{4}$ gas have been analysed over the E/N range from 1-300(Td) by the MCS and BEq methods using set of electron collision cross section determined by the authors. The swarm parameters and energy distribution function have been calculated for the pulsed Townsend, steady-state Townsend and Time of Flight methods. The results gained that the value of electron swarm parameters such as the electron drift velocity, the electron ionization and attachment coefficients and longitudinal diffusion coefficients in agreement with the experimental and theoretical data for a range of E/N. The electron energy distribution function has been explained and analysed in e$^{-10}$ -CF$_{4}$ at E/N : 5, 10, 100, 200, 300(Td) for a case of the equilibrium region in the mean electron energy and respective set of electron collision cross sections. The validity of the results has been confirmed by TOF and SST methods.

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Estimation of discharge coefficients of the broad-crested side weir with various levee's side slope of main channel (본류수로의 제방사면경사에 따른 광정횡월류위어의 유량계수 산정)

  • Kang, Ho-Seon;Cho, Hong-Je
    • Journal of Korea Water Resources Association
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    • v.49 no.11
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    • pp.941-949
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    • 2016
  • The flow characteristics of the broad-crested side weir considering the levee's side slope of main channel ($ES_{ch}$) was investigated through hydraulic experiment in order to estimate the discharge coefficient equation. For applicability to actual river, levee's side slope of main channel 1:0.5, 1:1 and 1:2 were selected. Experimental results show that the new estimated equation for the discharge coefficient including $ES_{ch}$ is reasonable and effective in actual applications by comparing estimated and measured discharge over side weirs. Through a multiple linear regression analysis the importance of variabes were ordered as $ES_{ch}$ > $h/y_u$ > $L/y_u$ > $Fr_u$. Especially the discharge coefficient equation without $Fr_u$ was suggested, and the high applicability was reviewed by comparing the measured and calculated overflow of broad-chested side weir.

Optimization for Roughness Coefficient of River in Korea - Review of Application and Han River Project Water Elevation - (실측 자료를 이용한 국내하천의 조도계수 산정 -적용성 및 한강의 계획홍수위 검토-)

  • Kim, Jooyoung;Lee, Jong-Kyu;Ahn, Jong-Seo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6B
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    • pp.571-578
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    • 2010
  • Manning's roughness coefficients were reevaluated for the computation of river flow of the Han River, the Nakdong River and the Geum River. The roughness coefficients were estimated by two methods. One is based on the assumption that roughness is primarily a function of grain diameter and the other is based on the findings that roughness may vary significantly with the flow discharge. The roughness coefficients adopted in each river improvement master plan have been compared with those obtained using the FLDWAV in this study, and their applicabilities have been reviewed, using the FLDWAV and HEC-RAS models. The design flood water levels computed by the abovementioned models with the roughness coefficients proposed in this study have shown good agreement with the measurements of time variation. The roughness coefficients computed using the FLDWAV model showed nearly no close correlation with the various hydraulic characteristic factors, such as grain size and river depth, etc.. Finally the design flood water levels and levee safety about the downstream part from the Paldang Dam of the Han River has been reviewed using HEC-2 model with roughness coefficients of this study and the results indicated that some parts of the existing levees were short of safety.

Determination of the initial cross-sections for the $C_4F_6$ molecule from the electron drift velocity ($C_4F_6$-Ar혼합기체에서의 Plasma Discharge Simulation을 위한 $C_4F_6$ 초기단면적 결정)

  • Lee, Kyung-Yeob;Jeon, Byung-Hoon
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.1544-1545
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    • 2011
  • For quantitative understanding of gas discharge phenomena, we should know electron collision cross section. Processing plasma etching of semiconductor, and research are being used in the etching source $C_4F_6$ gas may be used by itself and mixed with other gases are also used. However, the molecular gas $C_4F_6$ study on the characteristics of the electron transport and the cross-sectional area of the decision is still lacking. Therefore, we understand the electron transport characteristics and analysed the electron transport coefficients. And to understand and interpret physical properties of the ionization coefficient ${\alpha}$/N, and the attachment coefficient ${\eta}$/N in $C_4F_6$ gas.

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Numerical Investigation for Spray Angles of Dual Swirl Injector (Dual Swirl 인젝터의 분산각에 관한 해석적 연구)

  • 정해승;김선진
    • Journal of the Korea Institute of Military Science and Technology
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    • v.6 no.4
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    • pp.132-144
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    • 2003
  • Numerical analysis of the spray angles of Dual swirl injector were investigated to obtain basic design data and to predict the combustion performance. Using the commercial thermal hydraulic program, discharge coefficients and spray angles were numerically analyzed with recess length, pressure drop, velocity ratio, mixture ratio and back hole length. Water was used as simulants for oxidizer and fuel, respectively to compare the experimental results. Swirl injectors were designed to inject oxidizer of 70.5g/s and fuel of 29.5g/s at the pressure drop of 1MPa and two recess lengths were considered. In addition, the effect of injector geometry coefficient and velocity ratio on the discharge coefficient was studied.

A Numerical Study on the Turbulent Flow in the Discharge Flow Path from a Diffuser to a Wall (디퓨저에서 벽면으로의 방출유로에서의 난류유동에 관한 수치 해석적 연구)

  • Lee J.;Kim Y. I.
    • 한국전산유체공학회:학술대회논문집
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    • 2001.10a
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    • pp.44-50
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    • 2001
  • A numerical study was made to choose the better turbulence model for the flow in the discharge flow path from a diffuser to a wall. In this study standard $\kappa-\epsilon$ model(SKE), RNG $\kappa-\epsilon$ model(RNG), and Reynolds stress model(RSM) were applied. In case of the flow with relatively high Reynolds number at a diffuser inlet, the pressure loss coefficients by RNG have a tendency to be near to those by SKE at small ratio(below about 0.35) of $h/D_o$, but to those by RSM at large ratio(above about 0.35). At large ratio RNG begins to enlarge the effects of rapid strain and streamline curvature. RNG & RSM are recommended as the appropriate turbulence models for this case. But it is noticeable that the velocity gradient pattern in RNG is same as in SKE, and also that the total pressure distribution in RNG is same as in RSM only at swirling flow area, same as in SKE only at main flow area.

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