• Nuclear Engineering and Technology
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• 제29권1호
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• pp.15-24
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• 1997

The design and evaluation of a digital U-tube steam generator level controller of nuclear power plants, which uses model-based compensators to offset the inverse response behavior of water level, is described. Included is a review of steam generator level dynamics, a simulation model that replicates the effects of feedwater and steam flowrate as well as temperature on steam generator level, the design of both the compensators and the overall controller, and the results of simulation studies in which the performances of this model-based controller and existing analog ones were compared. The proposed digital steam generator level controller is stable and its use significantly improves the controllability of steam generator level.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.31-32
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• 2003

The fixation of reactive dyes onto cotton fabrics by means of dry heat treatment was examined in terms of water regain in fabrics. Dye liquors were applied to fabrics by ink-jet printer. The fixation strongly depended on water regain. At certain level of water regain the fixation showed stepwise increase. After this point the fixation reached to saturated value. The observed results were interpreted by the aggregation behavior of dyes and reactivity of hydroxyl group of cellulose depending on the amount of the surrounding water molecules. Urea molecules played a role of water at low water regain to increase the fixation.

• 임상간호연구
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• 제20권1호
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• pp.113-122
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• 2014

Purpose: The purpose of this study was to examine the effects of drinking water on the change in blood pressure after spinal surgery. Methods: A quasi-experimental nonequivalent control group, pretest and posttest design was employed. Subjects were consisted of 40 elderly patients who underwent spine surgery (20 in the experimental group, 20 in the control group). Data were collected from May 9th to September 30th, 2013. The experimental design involved patients drinking 400 mL of water in 5 mins after surgery and the blood pressure was measured in a standing position following the first 30 minutes after surgery. Control group received the same treatment and care as experimental group, except for the water intake. Data were analyzed using SPSS WIN 19.0 for $x^2-test$, t-test and independent t-test. Results: Experimental group with water intake demonstrated a significant higher level of systolic blood pressure compared to the control group (t=9.065, p=.005), but showed a non-significant level of diastolic blood pressure. Conclusion: This study indicates that water intake can be utilized as a useful nursing intervention to monitor changes in systolic blood pressure in elderly patients after spinal surgery.

• 산업기술연구
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• 제28권B호
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• pp.193-198
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• 2008

When the existing polder levee was constructed, the river's numerical analysis decided the bank raise by applying the planned flood stage or by using the result from the sectional 1st dimensional numerical analysis. But, it was presented that there is a limitation in the 1st dimensional value analysis when the structure like the polder levee obstructs the special shaped running water flow. Therefore, in order to verify the numerical value applicability when the polder levee is constructed, this report compared each other through the 1st and 2nd dimensional numerical analysis and the mathematical principle model laboratory. In case of the polder levee construction through the numerical analysis and the mathematical principle model laboratory, it was decided that there was no big problem in the 1st dimensional numerical analysis applied design, considering the uncertainty of mathematical principle analysis though the first dimensional numerical analysis was calculated a little bigger than the second. But, after construction, it was found that the water level deviation of the 1st, 2nd occurred biggest at the place where the flow was divided into two. Also, as a result of comparing the 1st, 2nd dimensional numerical analysis with the mathematical principle model laboratory, it was confirmed that the 1st numerical analysis applied design decreased the modal safety largely, as the left side water level was calculated smaller more than 0.5m in case of the 1st dimensional numerical analysis.

• 한국물환경학회지
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• 제33권2호
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• pp.187-196
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• 2017

To ensure hygienic safety of drinking water in a water storage tank, the concentrations of residual chlorine should be above a certain regulation level. In this study, we conducted model simulations to investigate the effects of temperature on residual chlorine in water storage tank conditions typically used in Seoul. For this, values of model parameters (decomposition rate constant, sorption coefficient, and evaporation mass transfer coefficient) were experimentally determined from laboratory experiments. The model simulations under continuous flow conditions showed that the residual chlorine concentrations were satisfied the water quality standard level (0.1 mg/L) at all the temperature conditions ($5^{\circ}C$, $10^{\circ}C$, $15^{\circ}C$, $20^{\circ}C$ and $25^{\circ}C$). Meanwhile, when the tanks had a no flow condition (i.e., no tap-water influent due to a sudden shut-down), the concentrations became lower than the regulatory level after certain periods. The findings from this modeling works simulating Seoul's water storage tanks suggested disappearance rate of residual chlorine could be reduced through the tanks design optimization with maintenance of low water temperature, minimization of air flow and volume, suppression of dispersion and the use of wall materials with low sorption ability.

• 한국정보통신학회논문지
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• 제10권10호
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• pp.1835-1841
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• 2006

해양환경 규제 MEPC의 규제 강화로 인하여 더욱 정밀하고, 신뢰성을 확보한 빌지분리 센서 시스템이 필요하다. 빌지 분류기를 설계 제작하기 위해서는 기름과 물을 구별하는 정밀한 유수분리 레벨센서가 필요하다. 이를 위하여 본 연구에서는 정전용량형 레벨센서의 특성 파악을 위해 3차원 시뮬레이션을 수행하여 특성을 파악하였으며, 이를 토대로 레벨센서의 설계시 주요한 설계인자를 추출하였다. 동작회로를 Digital 회로로 구성함으로써, 정전용량형 센서의 원천적인 기생커패시턴스 문제를 해결하였으며, 실험장치를 구성한 후 실험을 수행하였다. 실험 결과를 보면 노이즈에는 강인해졌음을 알 수 있었다. 그리고 추출한 정전용량형 레벨센서의 설계인자를 이용하여 정밀도를 향상시키기 위한 연구가 향후에 진행 될 필요성이 있다.

• 한국환경생태학회지
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• 제24권2호
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• pp.186-193
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• 2010

2006~2008년 동안 새만금 간척지에서 조성된 인공 염생식물 군락지와 새만금 방조제 배수갑문 수위 관리의 연관성을 밝히기 위해 배수갑문 수위특성 및 사유, 염생식물 군락지의 공간적인 분포와 형성 과정, 수위변화에 따른 염생식물 분포공간분석을 시도하였다. 배수갑문 수위조절의 특성을 분석한 결과, 파종 후 생장기의 평균수위와 연평균 수위와의 차이는 유사했으며, 연간 최저수위 및 최고수위가 파종 후 생장기에 나타났다. 3년동안 4,315만$m^2$에 염생식물 군락지가 형성되었으며 총 2,673만$m^2$에 대해 인공적인 염생식물 군락 조성이 시도되어 291만$m^2$을 제외한 표고 약 1m 이상의 2,382만$m^2$(89.1%)에 염생식물 군락지가 형성된 것으로 추정되었다. 파종지역 염생식물 군락지 형성에서 해수의 평균수위나 최저수위보다도 최고수위가 결정적인 요인으로 작용하였으며, 경운 및 토양 피막 여부가 군락지 형성의 2차적인 요인으로 작용한 것으로 보인다.

• 한국주거학회논문집
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• 제5권1호
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• pp.85-90
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• 1994

Using water in each apartment is influnced by several facters including the income level of inhabitants, the manner of life, the area apartments and climate. The automization of santory machines or facilites in recently bulit apartements has caused largely increases in amount of water use. Therefore the design for water supply is very important for the maintenance of the optimum level or pressure of water supply. This study is based on the offer of basic data for improving the quality of water supply and imploying the sanitory machine or sanitory facilites by analysis of amount increased of water use rapidly. The quantity of hot and cold water use by year is examined as a factor of construction in apartment.

• 한국생산제조학회지
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• 제21권6호
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• pp.946-953
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• 2012

When water shortage has been getting worse recently, toilet water-saving is one of the most effective way to solve the water shortage. Therefore, in this study, toilet flushing performance was investigated with VOF(Volume Of Fluid) model to obtain the basic design data for the development of high-efficiency toilets. The result showed that the shorter trapway, the longer the flushing duration time. However, the shorter trapway is found to have disadvantage in exhausting dirt due to relatively weak siphon and higher curvature. Since the remaining water in a trapway appears to help siphon, it is also an important factor in developing high-efficiency toilets. Although higher water level in the water tank shows better performance in flushing, lower water level is preferred to save water. Too low water level may cause dirt to clog the trapway due to relatively weak siphon.

• Physical Therapy Rehabilitation Science
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• 제1권1호
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• pp.17-21
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• 2012

Objective: To investigate the effect of long-term water exercise on gait parameters in the elderly post stroke patients. Design: One group pretest-posttest design. Methods: Twenty elderly post stroke patients (age: $56.5{\pm}10.1$ years, height: $168.6{\pm}5.8cm$, body mass: $69.3{\pm}6.9kg$, handicapped level: $2.5{\pm}0.8$) participated in this study. Participants took part in gait training of 1 hour per day, three days per week, for three months. Participants' gaits were analyzed to find the effect of 3 months water exercise by a 3-D motion analysis with 8 infrared camera and 1 force plate (sampling frequency: 100 and 1,000 Hz, respectively). A paired t-test was used to find the significance with significant level as 0.05. Results: Gait velocity, step length & step width significantly increased, and asymmetric index for gait parameters significantly decreased after the water exercise (p<0.05). Conclusions: The water exercise effectively affect on patients' gait ability and electromyography analysis will be needed further study.