Study on bubble and liquid velocities in an area-varying horizontal channel

Tran, Thanh Tram,Kim, Byoung Jae,Park, Hyun-Sik Elsevier 2018 Annals of nuclear energy Vol.118 No.-

<P><B>Abstract</B></P> <P>Two-fluid equations are widely used to simulate thermal-hydraulic phenomena in a nuclear reactor. Simulation accuracy depends on the modeling terms in the two-fluid equations. For a dispersed flow, the overall two-phase pressure drop by wall friction must be apportioned to each phase in proportion to the fraction of each phase (Kim et al., 2014). By applying this approach, the prediction of bubble phase velocity can be close to that of liquid for a fully developed flow in a horizontal pipe with a constant area. One may want to know what would happen in the area-varying channels. It is always true that the bubble density is much lower than the water density. Hence, the bubble would accelerate faster than the liquid in a nozzle in which the pressure decreases along the downstream; the bubbles would decelerate more quickly than the liquid in a diffuser in which the pressure increases along the downstream. The purpose of this study was to investigate those behaviors in an area-varying channel using the experimental data and MARS simulations. Experiments were made of turbulent bubbly flows in an area-varying horizontal channel. The velocities of two phases were measured with the help of the PIV technique. The experimental result showed that the two-phase velocities were no longer close to each other in the area-varying regions. The bubble was faster than the liquid in the nozzle region; in contrast, the bubble was slower than the liquid in the diffuser region. MARS code simulations were performed to assess the wall drag model. By replacing the original wall drag partition model in the MARS code with Kim’s one, the simulation results were consistent with experimental observations.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bubble and water velocities in an area-varying channel are measured. </LI> <LI> The phase velocities are very close in the constant-area region. </LI> <LI> The bubble is faster than the water in the contraction region. </LI> <LI> The bubble is slower than the water in the diffuser region. </LI> <LI> Kim’s wall drag partition model well predicts experimental results. </LI> </UL> </P>

심혈관계 질환으로 관상질환 집중치료실에 입원한 환자들의 혜후 측정을 위한 APACHEⅢ점수 체계의 임상적 유용성

이공섭,이창선,최현주,홍종서,강지향,김도형,이민영,오인균,김병엽,김상억,김학찬,한승혜,이재용,지영우,안경주 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.8

적외선 카메라 이용한 금속 내부 결함 평가에 관한 연구

김병희,김재열,최철준 朝鮮大學校 機械技術硏究所 2006 機械技術硏究 Vol.9 No.1

RT and UT are largely used as a non-destructive assessment of welding defects. RT shows difficulty in radioactive exposure and real-time detection. UT shows difficulty in quantitative detection of defects, and examination of a wide area in a short time. In order to settle the aforementioned disadvantages, many researchers try to find solution. In this paper, we apply a new examination method to verify the effectiveness in order to supplement the disadvantages of UT and RT, the existing non-destructive methods. The new method proposed in this paper is to use a difference in heat conductivity. If there is a discontinuous part, that is an internal defect. there is a difference in heat conductivity. Using this fact, it is possible to check the existence of an internal defect due to a temperature difference on the part with a defect and the part without a defect when the welded part is heated. The temperature difference on the surface indicated by the difference in heat conductivity can be checked for a wide area within a short time, by means of a thermal Image camera thereby to settle the disadvantage of the conventional non-destructive inspection methods. The thermal image method, however, has a disadvantage in that thermal load must be given to the tested sample and it is difficult to quantify measured data. In order to overcome this disadvantage, we will describe preliminary test and the like for applying thermal load on the tested sample including a welding defect, photographing images by means of a thermal image camera, analyzing thermal images, and analyzing welding defects.

전주산업단지 및 주변지역 VOCs 및 악취물질 모니터링

김용문,박비오,고영삼,심재정,송병식,양고수 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2002 工學硏究 Vol.33 No.-

Important main odorous compounds and VOCs(volatile organic compounds) possibly emitted from the Jeon-Ju Industrial Sites were identified and measured in amount through making air sampling over Jeon-Ju Industrial Sites and analyzing them with the sate of the art analytical instrument. Sampling sites were chosen 8 points by considering the industrial characteristics for the 1,2 Industrial Sites and 2 points for the 3 Industrial. Site Sampling times were two times, the first one was March. 2002 - April. 2002, and the second was May. 2002 - July. 2002. Canister sampling units and polyester bags were used to collect 6 liters air samples during 1hour or 3minutes for VOCs and polyester bags were used to sample 10 - 50 liters of air for 3 minutes depending on analytic characteristics of odor compounds. The important main VOCs were measured as acetone, ethyl benzene, n-hexane, m,p-xylene, toluene, M.E.K.(methyl ethyl ketone), isopropanol, ethyl acetate, o-xylene, n-butyl acetate, ethanol, benzene as in order of average concentration for the Industrial Sites. The main odorous compounds were COS, H2S, CS2, MM(methyl mercaptan), form aldehyde, acetaldehyde for the 1,2 Industrial Sites and COS, H2S, form aldehyde, acetaldehyde were measured as main species for the 3 Industrial Site. NH3 was measured as below the detection limit of the instrument. The concentrations of sulfide compounds for the 1,2 Industrial Sites were relatively higher than ones for the 3 Industrial Site. Among aldehydes, form aldehyde, acetaldehyde were detected very highly as 0.1- 1ppm over all the Industrial Sites.

Methylation이 心筋細胞膜에서의 ATP에 의한 Calcium Transport에 미치는 影響

金柱炳,昔廷鎬,李載欣 충남대학교 의과대학 지역사회의학연구소 1988 충남의대잡지 Vol.15 No.2

For the purpose of studying the properties of calcium pump, the effect of methy lation on the ATP-induced Ca-transport in the isolated porcine sarcolemmal vesicles which were loaded with high KCI was investigated. 1) Ca-transport by ATP was increased significantly, compared to control sarcolemmal vesicles. 2) Ca-transport of the vesicles preincubated in the methylation medium without PM II was increased by ATP, but less than control sarcolemmal vesicles. 3) Ca-transport of the vesicles preincubated in the methylation medium with PM II was decreased by ATP in the KCl medium, but increased in NaCI medium. But Ca-transport by ATP in the methylated vesicles in the reaction medium (NaCI and KC1) was significantly decreased, compared with Ca-transport by ATP in the nonmethylated vesicles. From the above results, it was suggested that methylation of membrane protein by PM II can change the membrane properties or the activity of calcium ATPase transporting calcium.

장애물 없는 주택 설계기준에 관한 연구 : 국내 공통주택의 무장애(barrier free) 설계수준 평가를 중심으로

김상운,박광재,강병근 한국의료복지시설학회 2004 의료·복지 건축 Vol.10 No.2

In this paper, the all units of residential housing that is not legislated in facility development law are analyzed and foreign design criteria that is related to barrier-free unit housing is comparing to domestic. Through the comparison in front door, living room, bathroom, bedroom, and kitchen, this paper aims to suggest internal barrier-free design criteria. This paper is limited to internal housing which are front door, living room, bedroom, bathroom, and kitchen. Also, the objectives of facility development law are U.S, Japan, German, and in case of U.S, UFAS is established by ADA, in Japan, Heart Building law and detail standard drawing are used, in German, DIN is used. The objective of domestic case study is the latest residential housings that are built over 2003. The flow of study is as follows ; First, the internal items of' residential housing are abstracted, and each item is checked in facility development law that is legislated in. Next, through comparison of domestic and foreign facility development law related to housing, common items are abstracted and detail standards are defined. Domestic residential housings are analyzed in those standards. Finally, the problems that is the result of analysis are analyzed and the barrier free design criteria is abstracted in unit housing. Also, more developed items and future study are suggested.

Glutaraldehyde로 가교시킨 BSA고정막에 의한 DL-Tryptophan의 흡착특성

김재훈,김민,김병식 한국공업화학회 2004 응용화학 Vol.8 No.1

A DEA group-containing polymer chain grafted onto a porous PE membrane. BSA was immobilized by the permeation of a BSA solution through the pore of the DEA membrane. The immobilized BSA was cross-linking with glutaraldehyde to prevent leakage. DL-tryptophan solution was forced to permeate through the BSA immobilized membrane at a flow 50mL/h. As a result, Adsorption of D-L-tryptophan increase with increasing of BSA immobilized as a function of the degree of GMA grafting.

치과 방문 시 어린이와 부모의 치과 불안도의 상관 관계

김성희,백병주,김재곤,양연미,권병우 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.2

어린이에게 있어서 치과 불안의 문제는 오랫동안 환자 행동조절의 문제로서 여겨져 왔으며 이러한 문제로 인해 치료 시의 비협조도, 치료 악속 취소 및 회피 둥이 발생할 수 있다. 따라서 치과의사 및 치과 팀에게 가능한 한 빨리 어린이의 치과 불안을 인지하여 적절히 대처할 것이 요구 되어진다. 한편, 부모의 치과 불안이 그들의 아이의 치과 불안과 치료 협조도에 영향을 줄 수 있음이 이전의 여러 연구들로부터 언급 되어지고 있다. 또한 치과 방문 결정의 주체가 어린이라기보다는 부모임을 고려할 때, 부모와 어린이 사이의 치과 불안도의 관계 규명이 중요하다 하겠다. 본 연구는 전북대학교 병원 소아치과에 내원한 3~10세(평균 연령 5.27세, 표준 편차 2.172세)의 어린이 78명(남아 45명, 여아 33명)과 그들의 부모 78명을 대상으로 하였으며, 치과 치료 전의 어린이의 치과 불안도 평가를 위해 Venham Picture Scale을, 부모의 치과 불안도 평가를 위해 Corah's dental anxiety scale을 사용하여 두 값을 비교하였다. 또한 어린이의 치료 시 협조도, 기질, 성별, 나이, 부모의 교육 정도를 평가하여 치과 불안도와 비교하였다. 이에 다음과 같은 결론을 얻었다. 1. 어린이의 치과 불안도와 부모의 치과 불안도 사이의 상관 분석 및 회귀분석에서 상호 관계성이 존재하였다(P<0.02). 2. 어린이의 치과 불안도와 치료 협조도사이의 상관 분석 및 교차 분석에서 음의 상호 관계를 나타내었다(P<0.001). 3. 어린이의 치과 불안도와 기질에 관한 Student's t-test에서 낮은 불안도와 높은 불안도 그룹의 네 가지 기질 평균 점수비교 시, 낮은 불안도 그룹에서 모두 약간 낮은 평균 점수를 보였으나 통계학적 유의차는 없었다(P>0.1) 4. 어린이의 치과 불안도와 어린이의 성별, 나이에 관한 Student's t-test에서, 여아에서 높은 불안도, 3~6세의 어린 그룹에서 높은 불안을 보였다(P<0.001). 5. 부모의 치과 불안도와 부모의 학력에 관한, Student's t-test에서, 대학교육을 받지 않은 저학력 부모 그룹에서 더 높은 불안도를 보였으나 통계학적 유의차는 없었다(P>0.1). In children, dental anxiety of dental treatment has been recognized as a source of problems in patient management for many years. Dental anxiety can be causes of negative cooperation, cancel and avoid of dental treatment. Therefore, dentist and dental team should recognize of child's dental anxiety as early as possible and manage appropriately. In previous studies, it is reported that parental dental anxiety affect dental anxiety and cooperation of their child. And it is parental decision which results in a child's visit to the dentist, rather than a child's decision in most cases. Therefore, it is important to identify the relationship of dental anxiety between child and parent. We estimated child's dental anxiety before dental treatment using Venham Picture Scale that is useful even a very young child and parental dental anxiety using Corah's dental anxiety scale. Then, two values above were compared. Child's cooperation, temperament, sex, age, parental education were estimated and compared with dental anxiety, too. The results were as follows: 1. There are positive relationship of dental anxiety between child and parent with the correlation analysis (P<0.02). 2. There are negative relationship of child's dental anxiety and child's cooperation with the correlation and regression analysis (P<0.001). 3. Low anxiety group has lower mean value of four temperament item with the Student's t-test. But, there is no statistical differences (P>0.1). 4. Girl and younger group have higher mean value of dental anxiety than boy and older group with the Student s t-test (P<0.001). 5. Low educated parents have higher mean value of dental anxiety than high educated parents with the Student s t-test (P>0.1).

BSA고정화를 위한 가교제의 첨가특성

김재훈,김민,김병식 한국공업화학회 2004 응용화학 Vol.8 No.2

Anion exchange groups(DEA) were introduced into porous hollow fiber membranes by radiation-induced ploymerization. A DEA group-containing polymer chain grafted onto a porous PE membrane. The BSA solution was forced to permeate across the hollow fiber DEA membrane. BSA was immobilized by the permeation of a BSA solution through the pore of the DEA membrane. The immobilized BSA was cross-linking with glutaraldehyde to prevent leakage. Afterwards, The GA 0.05 percent membrane having higher adsorption capacity than 0.025, 0.075, 0.1 percent GA concentration.

기도 이물의 임상적 고찰

김영석,이승규,이민재,백병준,오천환 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.2

Aspiration of foreign bodies into the airway is a common problem in spite of efforts to educate the public and it can be sometimes fatal accidents. A retrospective study has been performed for 34 cases of airway foreign bodies, which were obtained from April 1994 to August 1998 at Chunan hospital of Soonchunhyang University. The results were as follows: 1) Among the 34 cases, 26 cases(76.4%) were under the age of 3. The ratio of male and female was 1.4:1. 2) The most common symptom after foreign body aspiration was intractable cough(38.2%). 3) Abnormal findings in the chest X-ray films were found 24 cases(70.6%) and the most common abnormal radiologic feature was combination of pneumonia and atelectasis(37.5%), followed by combination of pneumonia and emphysema(16.6%), pneumonia alone(16.6%). 4) The nature of foreign body was vegetables in 20 cases(58.8%), miscellaneous in 11 cases(32.4%), metals in 2 cases(5.9%) and plastics in 2 cases(5.9%). 5) By distribution of the location of foreign bodies, 26 cases(76.4%) were located in the main bronchus(20 cases in right side and 6 cases in left side), 5 cases were in trachea, 2 cases were in larynx and 1 case was located at carina level. 6) By duration of foreign body lodgement in the airway, 15 cases(44.1%) were found within 24 hours, 9 cases(26.5%) were within 7 days, 7 cases(20.6%) were within 30 days and 3 cases(8.8%) were found over 1 month. 7) In mode of treatment, ventilating bronchoscopic removal under general anesthesia was performed in 29 cases(85.3%), thoracotomy with bronchotomy in 2 cases, thoracotomy with lobectomy in 1 case and postural drainage in 2 cases. 8) Complication rate according to the nature of foreign body was most high in vegetables(68.2%). 9) Correlation between complication rate and the duration of the foreign bodies in situ was definite.