• Title/Summary/Keyword: Circulation control

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A Numerical Study on Flow Control Structure of a New-Type Submerged Breakwater (신기능 잠제의 흐름 제어 기능에 관한 수치적 연구)

  • Hur, Dong-Soo;Lee, Woo-Dong;An, Sung-Wook;Park, Jong-Bae
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.3
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    • pp.181-190
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    • 2010
  • In case of constructing submerged breakwaters, the circulation current is occurred around the open inlet because of mean water level difference between front and rear sides of them. The aim of this study is to investigate the flow control structure of new-type submerged breakwater which is able to reduce mean water level at rear side of it. At first, the numerical model (LES-WASS-3D) is validated by comparing with existing experimental data. And then, numerical simulation is carried out to examine wave height, mean water level and mean flow around the newtype submerged breakwater. From the numerical results, it can be pointed out that the new-type submerged breakwater with drainage system reduces the rip current around the open inlet.

Odor Removal with Powdered Adsorbent using Bag-filter System (분말 흡착제를 이용한 악취 저감 여과 집진장치 개발연구)

  • Xu, Rong-bin;Kim, Tae-Hyeung;Ha, Hyun-Chul;Piao, Cheng-Xu
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.27 no.4
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    • pp.291-301
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    • 2017
  • Objectives: In order to improve the working environment and solve the complaints, many efforts have been made to remove the odor from the industrial process. There are many disposal methods to remove odor, but there are many disadvantages and inadequate applications. The Purpose of this study was to develop a bag-filer system for odor removal using powder adsorbent. Methods: The bag-filter system is composed of a shear bag filter, an absorbent spraying system and an absorbent circulation system. The spraying absorbent system was connected with the inlet duct of the shear bag filter for inputting adsorbent. And the absorbent circulation system can transport the collecting adsorbent from hoper to the inlet duct of the system. As a result, the adsorbent can remove odor with recycling in the system. Also affective factors like the powdered absorbent combination and injection method was researched for maximization of system efficiency. The study was conducted in two stages. The first step was testing equipment made and the second is to evaluate the efficiency of the odor control by connecting to the actual odor generation process. Results: Both experiment stages showed efficient odor control ability. The adsorption efficiency of the system is demonstrated and the odor was adsorbed well by the powder adsorbent. It is essential to accurately understand the characteristics of the odorous and use the appropriate adsorbent. Although the powder adsorbent was used in the experiment, the problem of scattering did not occur due to the high degree of system sealing. Also the system manufactured in this study was designed to recycle the adsorbent, so adsorbent reuse or batch processing is convenient. Conclusions: The applicability of the system has been proven through this research. Customized systems for industrial process and the appropriate adsorbent base on the characteristics of pollutant generation will show efficient odor collection ability.

Assessing the risk of recurrence of porcine epidemic diarrhea virus in affected farms on Jeju Island, South Korea

  • Jang, Guehwan;Lee, Sunhee;Lee, Changhee
    • Journal of Veterinary Science
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    • v.22 no.4
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    • pp.48.1-48.15
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    • 2021
  • Background: Porcine epidemic diarrhea virus (PEDV) is a swine enteropathogenic coronavirus that has devastated the swine industry in South Korea over the last 30 years. The lack of an effective method to control the endemics has led to a surge in PEDV recurrences in affected farms throughout the country. Objectives: In the first step toward establishing systematic monitoring of and active control measures over the swine populations, we constructed an assessment model that evaluates the status of (1) biosecurity, (2) herd immunity, and (3) virus circulation in each of the PEDV-infected farms. Methods: A total of 13 farrow-to-finish pig farms with a history of acute PEDV infection on Jeju Island were chosen for this study. The potential risk of the recurrence in these farms was estimated through on-site data collection and laboratory examination. Results: Overall, the data indicated that a considerable number of the PEDV-infected farms had lax biosecurity, achieved incomplete protective immunity in the sows despite multi-dose vaccination, and served as incubators of the circulating virus; thus, they face an increased risk of recurrent outbreaks. Intriguingly, our results suggest that after an outbreak, a farm requires proactive tasks, including reinforcing biosecurity, conducting serological and virus monitoring to check the sows' immunity and to identify the animals exposed to PEDV, and improving the vaccination scheme and disinfection practices if needed. Conclusions: The present study highlights the significance of coordinated PEDV management in infected farms to reduce the risk of recurrence and further contribute towards the national eradication of PEDV.

A Study on the Architectural Planning of Clinical Practice Spaces at the College of Medicine (의과대학의 임상실습공간에 관한 건축계획 연구)

  • Choi, Kwangseok
    • Journal of The Korea Institute of Healthcare Architecture
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    • v.27 no.4
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    • pp.7-14
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    • 2021
  • Purpose: This study summarized architectural planning data for clinical practice spaces for CPX/OSCE and Simulation spaces, through analysis of domestic and foreign literature and a survey of domestic colleges of medicine. Methods: This study analyzed the architectural planning elements of the clinical practice spaces of the college of medicine, through a literature review on the clinical practice space and the survey of four recently established colleges of medicine. Results: ① It is desirable to plan the floor plan type for Simulation and CPX/OSCE spaces as a corridor-separated type that separates the circulations between students and staff (faculty). ② The simulation area arranges their practice rooms around the control space where the circulation of the staff is made. Conversely, it is desirable to arrange the CPX/OSCE rooms around the test waiting room where students enter. ③ It is desirable to separate access to the staff and students to allow student control, and to install various support spaces facing the staff corridor to secure the movement of equipment and the flow of evaluators. ④ In the simulation area, the equipment stored in the storage must be set in each room before the practice according to the setting of delivery or surgery like, and the equipment that has been removed must be back, so the circulation is short and does not intersect with the student circulations. ⑤ Debriefing rooms, seminar rooms, etc. are arranged in the staff area for review and discussion of clinical situations where practice and evaluation have been completed. Implications: It is important to configure an appropriate movement system and spatial zoning for each space for simulation and CPX/OSCE.

Control Simulation of Left Ventricular Assist Device using Artificial Neural Network (인공신경망을 이용한 좌심실보조장치의 제어 시뮬레이션)

  • Kim, Sang-Hyeon;Jeong, Seong-Taek;Kim, Hun-Mo
    • Journal of Biomedical Engineering Research
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    • v.19 no.1
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    • pp.39-46
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    • 1998
  • In this paper, we present a neural network identification and a control of highly complicated nonlinear left ventricular assist device(LVAD) system with a pneumatically driven mock circulation system. Generally, the LVAD system needs to compensate for nonlinearities. It is necessary to apply high performance control techniques. Fortunately, the neural network can be applied to control of a nonlinear dynamic system by learning capability. In this study, we identify the LVAD system with neural network identification(NNI). Once the NNI has learned the dynamic model of the LVAD system, the other network, called neural network controller(NNC), is designed for a control of the LVAD system. The ability and effectiveness of identifying and controlling the LVAD system using the proposed algorithm will be demonstrated by computer simulation.

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The Effects Of Chekamuiyiin-tang On Biochemical And Histological Changes Of Rats Fed High Diet (체감의이인탕이 고지방식이로 유발한 비만 흰쥐의 생화학 및 조직화학적 변화에 미치는 영향)

  • 최원호;서부일
    • The Journal of Korean Medicine
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    • v.21 no.3
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    • pp.31-39
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    • 2000
  • Objectives : Chekamuiyiin-tang has effects of promoting diuresis, promoting blood circulation, elimating phlegm and strengthening the body's resistance to disease. We experimented with Chekamuiyiin-tang in order to find effects which might possibly cure obesity. Methods : We fed a control group of rats a high fat diet and administered normal saline for 8 weeks. And we fed an experimental group of rats a high fat diet and administered an extract of Chekamuiyiin-tang for 8weeks. Results : The serum total cholesterol level, triglyceride level, free fatty acid level, total lipid level and phospholipid level in the Chekamuiyiin-tang group showed a significant decrease in comparison with the control group. The serum HDL-cholesterol level in the Chekamuiyiin-tang group showed no change in comparison with the control group. The serum LDL-cholesterol level in the Chekamuiyiin-tang group showed a decrease in comparison with the control group, but this result showed no efficacy. The size of the epididymal fat cell and the fat drops area in the hepatic lobule of rats in the Chekamuiyiin-tang group showed a significant decrease in comparison with the control group. Conclusios : According to the above results, Chekamuiyiin-tang has shown to be capable of curing and preventing obesity.

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Investigation for the Induction of Quality Inscription System with Herbal Medicine (한약재 품질 표시 제도의 도입을 위한 조사)

  • Lee, Mi-Young;Kim, Ho-Kyoung;Jeon, Won-Kyung;Jung, Gye-Jin;Ju, Young-Seung;Ju, Young-Seung;Ko, Byoung-Seob
    • Korean Journal of Oriental Medicine
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    • v.6 no.1
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    • pp.59-68
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    • 2000
  • The purpose of this study is to encourage the circulation of good quality of oriental medicine and to improve national welfare. Investigation for the induction of quality inscription system was conducted by mail and interview. The data were analyzed by SAS. The major results were as follows: The portion of subjects agree to necessity of quality inscription was 78.5%. In the question of side effect against quality inscription, the rate of negative was 67.7%. The responses answered that the necessity of quality inscription was not economical profit but authority of knowledge and improvement on health(37.8%), established market for herbal medicine(34.7%) and effect of clinical care(23.9%), respectively These results might be useful information for establishing of quality inscription system for herbal medicine.

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SEPARATION CONTROL MECHANISM USING SYNTHETIC JET ON AIRFOIL (익형에서의 synthetic jet을 이용한 박리제어 mechanism)

  • Kim, S.H.;Kim, W.;Hong, W.;Kim, C.
    • 한국전산유체공학회:학술대회논문집
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    • 2007.10a
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    • pp.60-66
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    • 2007
  • Separation control has been performed using synthetic jets on airfoil at high angle of attack. Computed results demonstrated that stall characteristics and control surface performance could be substantially improved by resizing separation vortices. It was observed that the actual flow control mechanism and flow structure is fundamentally different depending on the range of synthetic jet frequency. For low frequency range, small vortices due to synthetic jet penetrated to the large leading edge separation vortex, and as a result, the size of the leading edge vortex was remarkably reduced. For high frequency range, however, small vortex did not grow up enough to penetrate into the leading edge separation vortex. Instead, synthetic jet firmly attached the local flow and influenced the circulation of the virtual airfoil shape which is the combined shape of the main airfoil with the separation vortex. Theses results show the characteristic of unsteady flow of single synthetic jet. Beside, we researched on multi-array synthetic jet to obtain applicable synthetic jet velocity. Multi-location synthetic jet is proposed to eliminate small vortex on suction surface of airfoil. With the results, we concluded that the flow around airfoil is stable by high frequency synthetic jet with elimination of small vortex and confirmation of stable flow. Moreover, performance of multi-array/multi-location synthetic jet can be improved by changing phase angle of multi-location synthetic jet.

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Quality Control of the Educational Contents based on Life Cycle (생명주기 기반 교육용 콘텐츠 질 관리)

  • Lim, Jae-Hyun;Kim, Chi-Su
    • Journal of The Korean Association of Information Education
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    • v.11 no.4
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    • pp.483-495
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    • 2007
  • In this paper, to establish a way controlling educational contents, range of contents for quality control are offered. And a life-cycle suitable for present circumstance has defined and successive quality control process has suggested supporting development and use of the contents through analyzing the life cycle of its software and previous contents. A life cycle is defined as whole process from formation of contents to its extinction. The developing process includes stages of planning, designing, manufacturing, and the applying process includes evaluation, circulation and management. Suitable quality control guidelines for each process have established and offered. Aim of this paper is also to develop a model which is applicable to developers as well as supporters who help the developing process.

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Management of powdery mildew and leaf mould on tomato organically cultivated under controlled structured condition

  • Kim, Yong-Ki;Hong, Sung-Jun;Jee, Hyeong-Jin;Park, Jong-Ho;Han, Eun-Jung;An, Nan-Hee;Choi, Eun-Jung;Ryu, Kyoung-Yul
    • Korean Journal of Organic Agriculture
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    • v.19 no.spc
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    • pp.283-286
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    • 2011
  • Powdery mildew and leaf mold were major diseases in organic cultured tomatoes. $NaHCO_3$ and $KH_2PO_4$ were selected as control agents for controlling tomato powdery mildew. Control effect of the selected control agents was increased when they were treated with oil-egg yolk mixtures (OEYO). Also four organic materials used commercially including copper hydroxide and sulfur, showed high control effect more than 90% in green house. Also two organic matters, copper hydroxide and sulfur showed high control effect in farmer's field. When tomatoes were cultivated in plastic house installed with circulation fan, incidence of powdery mildew and leaf mold was reduced by 56% and 60%, respectively.