• Journal of Environmental Impact Assessment
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• v.12 no.2
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• pp.73-86
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• 2003

In this study, we performed 8 times of water quality sampling and continuous measurement of flow to identify wastewater flow characteristics for wastewater treatment basins of Namyangju city. The field survey has been conducted 6 times in dry weather period and 2 times in wet weather period. Each survey conducted 24-hr water quality sampling in the interval of 2-hr. From the analysis of flow data and water quality data, the following conclusions can be drawn. For Namyangju-1 station, which represents residential and commercial mixed area, flow rises early in the morning before office-going hour and moves up and down within narrow range, and lasted after office-leaving hour, resulting from continuous commercial activity. In case of Namyangju-5 station representing community and Namyangju- 6 station representing residential area, the flow immediately falls down after rising early in the morning and later rises again at the office-leaving hour, and arrives at peak flows around late evening. In the analysis of wastewater characteristics for weekdays and weekends, without landuse types the flow rate of weekends is higher than that of weekdays because it reflects population, being not contributed to generate wastewater during the working hours of weekdays, stay home and produce wastewater for weekends period.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.7
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• pp.793-800
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• 2019

Recently, VR technology has been able to enjoy VR content using HMD due to changes in hardware and displays. VR video contents and HMD are becoming interactive through human senses and computer interfaces. Based on flow based on VR user's perspective, VR video contents and HMD were approached as subjects for continuous use. The components of the independent variable Flow were set up in real life, immersion, and interaction. Data from 400 male and female users of 450 users commissioned by the survey agency were used in the study. Research shows that first flow influences VR video contents and continuous use. Second, flow has been shown to affect HMD and its continued use. Among the flow factors that enhance the persistence of VR video content and HMD, which act as the greatest influence was studied. Through this research, the company aims to help establish direction of the next-generation VR industry

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.319-326
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• 1998

Anodic half-reaction in the $Na^+$ ionic sensors using $Na_2CO_3$ and $MCO_3$ ($M=Cs_2,K_2,Li_2,Ca$) as a sensitive membrane is derived in continuous flow system to explain $CO_2$ sensing characteristics. For various gas-sensitive membranes, a well known overall reaction, $MCO_3\;=\;MO\;+\;CO_2$, cannot be applied for the EMF behaviors of these kinds of sensors. So, the anodic reaction is found to involve $Na_2CO_3$ and $M^{++}$-containing oxide phases by employing the ion exchange reaction at the interface of solid electrolyte and the sensitive membrane to maintain ionic balance in the whole cell. Based on the electrode reaction derived in flow system, differences of cell potentials between continuous and discontinuous flow systems were also discussed. These EMF differences were considerably caused by the partial pressures of oxygen and $CO_2$ as well as irreversible chemical reactions between electrode materials and $CO_2$ atmosphere.

• Membrane Journal
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• v.14 no.1
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• pp.75-84
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• 2004

In this study, we present a noble study far membrane transport models using chlorine resistance of polyamide RO membranes. Membrane transport mechanism is investigated by the comparison of membrane permeation performance under the continuous and Intermittent operation modes with mixed feed solution containing NaOCl and NaCl. Analysis of permeation performance indicates that solution-diffusion model and preferential adsorption-capillary flow model are relatively efficient according to operation mode. Under the continuous flow state, mass transfer depends on preferential adsorption-capillary flow model rather than solution-diffusion model. On the other hand, it prefers solution-diffusion model to preferential adsorption-capillary flow model under the stationary state. SEM images of NaOCl treated membrane surfaces strongly support these conclusions. These surface images reveal that NaOCl treated membrane in continuous operation mode exhibits ridge and valley structure in some fraction of the surface area, whereas that in intermittent operation mode shows surface degradation entirely.

• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.33-38
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• 2001

The subsidence characteristics of artificial reef (AFR) in the unsteady flow such as tidal flow were investigated. The scour and subsidence characteristics were confirmed in the steady flow field. In a main study, the interaction of "Flow - Sediment Movement - Structure Behavior" and scou $r_sidence mechanism were discussed int he unsteady flow field. AFR subsidence characteristics was discussed with Reynolds number(Re*), Shields number(Sn*), dimensionless acceleration of flow (af/g) and dimensionless time (t/T). Most of all, the continuous AFR subsidence from the scour was occurred by periodic behavior of AFR. This behavior is result from the asymmetric ground, and is influenced by maximum velocity, duration time and direction of flow.ow.

• Bulletin of the Korean Mathematical Society
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• v.36 no.4
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• pp.707-716
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• 1999

In this pater we study the continuity of rotation numbers of liftings of circle maps with degree one. And apply our result to prove that a positively equicontinuous flow of homeomorphisms on the circle $S^1$ is topologically conjugate to a continuous flow of rotation maps.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.777-783
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• 2000

Composting by negative aeration is a reasonable proposition to control odor generated during composting process. Cattle manure and rice hulls mixtures were composted in a bin composting system by negative aeration. Continuous(CA) and intermittent(IA) aeration methods were applied to analyze the composting characteristics. The composting temperature and the ammonia emission during composting were investigated according to the aeration methods. The main problem for the negative aeration was the generation of condensate in the suction line of blower. The quantity of condensate was significant for continuous aeration. The aeration method should be modified to escape from the cooling effect of continuous aeration at the initial stage of composting. It took a longer time to finish a composting for intermittent aeration on account of lower aeration. It was concluded that the composting by negative aeration could be accomplished by either continuous or intermittent aeration method if the flow rate would be controlled more efficiently and the water vapor in suction line of blower could be removed effectively. Ammonia emission increased up to maximum value of 675ppm for continuous aeration while 300ppm for intermittent aeration. However, the cumulative value of ammonia emission was larger for intermittent aeration than for continuous aeration.

• Quality Improvement in Health Care
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• v.7 no.2
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• pp.244-261
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• 2000

Background : In order to cope with changes in the management environment at hospitals, increased interests are drawn in patient foodservice system on Continuous Quality Improvement Activity as the method of approaching a quality food service and effective management. Thus, as a part of this activity, this study was conducted to evaluate job flow improvement that was already performed and the results of that process at the dietetic department of a university hospital, focusing on improving management. Method : On February 15 of 1998. the dietetic department formed a job flow-improvement to decide on the priority of job flow improvement, and prepared specific action strategies and schedule of the priority: after a 5 month process period, job improvement achieved on June 15. 1998. Also, economic achievement of the task was evaluated through labor productivity analysis and cost-benefit analysis. Results : The patient food service system which was managed decentralized at the present hospital was centralized, some steps of the food service process were integrated, and quality of patient food was improved. Also, as a solution of the problems expected when conducting job flow improvement was made on food service equipments and utensils. The result of evaluating the job flow improvement that labor productivity improved by 18.2% compared to before the improvement and the result of the analysis of cost-benefit showed that Benefit-Cost (B/C) ratio was 2.22. showing financial merit on the investment. Conclusions : Continuous Quality Improvement Activity needs to be initiated and conducted in the future in various areas of hospital foodservice system in order to actively adopt to ever changing hospital management environment. In order to achieve this goal, many researches and more efforts need to be put in by people in charge of hospital food service management, and interests and support are needed from hospital policy makers.

• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.157-164
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• 2007

Microencapsulation of cells within microfluidic devices enables explicit control of the membrane thickness or cell density, resulting in improved viability of the transplanted cells within an aggressive immune system. In this study, living cells (3T3 and L929 fibroblast cells) are encapsulated within a semi-permeable membrane (calcium crosslinked alginate gel) in two different device designs, a flow focusing and a core-annular flow focusing geometry. These two device designs produce a bead and a long microfibre, respectively. For the alginate bead, an alginate aqueous solution incorporating cells flows through a flow focusing channel and an alginate droplet is formed from the balance of interfacial forces and viscous drag forces resulting from the continuous (oil) phase flowing past the alginate solution. It immediately reacts with an adjacent $CaCl_2$ drop that is extruded into the main flow channel by another flow focusing channel downstream of the site of alginate drop creation. Depending on the flow conditions, monodisperse microbeads of sizes ranging from $50-200\;{\mu}m$ can be produced. In the case of the microfibre, the alginate solution with cells is extruded into a continuous phase of $CaCl_2$ solution. The diameter of alginate fibres produced via this technique can be tightly controlled by changing both flow rates. Cell viability in both forms of alginate encapsulant was confirmed by a LIVE/DEAD cell assay for periods of up to 24 hours post encapsulation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.1-8
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• 2005

This paper explored the effects of separation control through the use of pulsating jet blowing on a two dimensional elliptical airfoil. To develop an active control technique of flow separation, a flow control actuator utilizing continuous/pulsed jet of pressurized air was designed and installed in a wind tunnel testing model of elliptic wing. PIV measurement and flow visualization of the wing near field were conducted to access the feasibility and effectiveness of the pulsed jet blowing on controlling the stall of the elliptical wing in subsonic flow. PIV experimental results show that separation control can provide significant reduction in turbulent flow wake and separation bubbles by jet blowing. The pulsating jet blowing is more effective on the separation control than continuous one. Increased jet frequency suppressed the turbulent separated flow wake effectively at even higher AOAs.