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

초등학교 고학년 학생의 구강보건에 관한 인식 및 행동

김영경,문혁수,정재연,한수진,이병진,김은경,정혜련 韓國學校保健學會 2001 韓國學校保健學會誌 Vol.14 No.1

The purpose of this study was to collect basic data for the development of effective oral health education program in elementary school. The subjects in this study were 604 fourth-year, fifth-year and sixth-year students of an elementary school in Seoul. Oral health awareness and behaviors were surveyed and analyzed. The findings of this study were as follows: 1. The most common time for toothbrushing was after dinner(62.0%) and before bedtime(62.3%). By school year, the largest number who brushed their teeth after dinner were fourth and fifth graders while the greatest number who did so after breakfast were sixth graders Seventy-four percent of respondents brushed the teeth twice or more a day. By school year, the fifth-year students brushed their teeth the least while girls outperformed the boys in daily toothbrushing frequency(p<0.05). Regarding the intake of cariogenic food, 62.1% took that kind of food once or more a day. By school year, the fifth graders took the most (p<0.05), and girls took more cariogenic food than the boys(p<0.05). 2. Ninety percent of the respondents had visited a dental clinic. By grade, the sixth-year students had visited a dental clinic more frequently and girls more frequently than boys. Eighty percent of the respondents visited a dental clinic to receive treatment but just 12.3% visited a dental clinic to prevent oral diseases. Concerning the fetor of dental treatment only 14.4% expressed fear. School year made no difference, yet the percentage of girls who experienced fear was higher than that of boys(P<0.05). Regarding preventive treatment, 39.7% experienced pit and fissure sealing and 24.2% experienced the application of fluorides. All the students hadn't much experience in preventive treatment regardless of school year -- gender didn't make a difference. 3. Fourty-six percent of respondents had a preference for the fluoride mouth rinsing program; 38.4% wanted that grogram to continue. As to the reason for preference, 38.2% preferred it because of the prevention of dental caries, 43.0%, the largest percentage, didn't favor it because they found it too much trouble to do(some of the respondents gave two different answers). 4. Despite an increase in the frequency of toothbrushing at the right time, they still took cariogenic food frequently Their visit to a dental clinics also aimed at treatment more than at prevention, and they had very narrow experience of preventive treatment. Furthermore, the fluoride mouth rinsing program failed to draw their interest. Therefore, it is recommended that a successful real health education program should be developed.

신생아에서 용질배설에 관한 연구

김경범,박재현,최병민,이현희,윤재균 관동대학교 의과학연구소 2000 關東醫大學術誌 Vol.4 No.1

Purpose : Determination of urinary concentration in neonate is mandatory for precise management of fluid and electrolyte requirements. Although measurement of urine specific gravity has been proposed far monitoring fluid requirements, the reliability of specific gravity does not accurately predict urine osmolalities in the neonate period. So specific gravity should be checked by measuring the osmolality. Also the urinary excretion of creatinine has been used for the assessment of hydration state. We present the result of specific gravity, urine osmolality, urine creatinine in a spot urine sample during the first week of life as a reliable reference standard. Methods : Spontaneously-voided urine sample were obtained in 40 full term neonates. Two urine samples were available with a interval of 4 to 7days (A: 1st day, B: 4 - 7days), Urine sample was tested for specific gravity with a strip test. Also urinary osmolality, urinary creatinine, urinary creatinine/osmolality ratio were measured. Results : The mean of specific gravity tested by the strip test was 1.006±0.0040 (A) , 1.005±0.0036 (B). The mean of urine osmolality and creatinine were 177.7 ± 103.0 and 30.9±21.6 (A), 145.7 ±90.3 and 26.4± 17.7 (B). The mean of excretion rate of urine creatinine/osmolality ratio was 18.2 ±8.5 (A), 19.4 ±9.1 (B). There was correlation between urine specific gravity and osmolality in neonate(r=0.833(A), 0.842(B) p<0.001). Urinary creatinine/osmolality levels of the first urine samples were closely correlated with the second samples (r=0.617, p<0.001). Conclusion : Specific gravity of urine was enough to predict the osmolality in neonate. But Specific gravity should be checked by measuring the osmolality of urine. Urine osmolality and creatinine were spread over a wider range and did not used to urinary excretion of solute in neonate. Urinary creatinine/osmolality ratio can be used to standadise the urinary excretion on solute in the first week of life.

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.

백서 척수후근절로부터 슈반세포의 효과적인 체외 배양법

김성민,이종호,김남열,안강민,최원재,최시호,차미주,이주영,황순정,장정원,명훈,최진영,서병무,정필훈,김명진 大韓顎顔面成形再建外科學會 2003 Maxillofacial Plastic Reconstructive Surgery Vol.25 No.4

Schwann cells(SCs), an important component of the peripheral nervous system, intract with nerous to mutually support growth and replication for the peripheral nerve regentation. Recently, ading SCs to the lumen of guidance channel is widely tried to improve regeneration or to make regeneration possible over otherwise irreparable gaps. however, it is not easy to isolate and multiplicate SCs as much as enough to help the axonal regeneration. For the allogeneic SCs source for tubular nerve guidance, we developed a little bit improved technique of harvesting and multiplicating SCs. by culturing dispersed dorsal root ganglia in specially designed medium with growth factors and serial processing, we repeatedlly generate relatively homogenous SC cultures. Our technique was compared with other methods of literature using immunostaining methods such as GFAP, S100, BDNF and the total SC count assessment at different time interval after primary culture.

이성질체 분리를 위한 음이온교환재료의 합성

김재훈,김민,김병식 한국공업화학회 2003 응용화학 Vol.7 No.2

Anion exchange groups were introduced into porous hollow fiber membranes by radiation-induced ploymerization. The epoxy group produced in the GMA-grafted hollow fiber membrane was converted into anion-exchange groups by reaction with Diethylamine(DEA). Triethylamine(TEA). Ethanolamine(EtA). Diethanolamine(DEtA). The D-, L-Tryptophan solution was forced to permeate across the hollow fiber DEA, TEA, EtA, DEtA memberan. When measurements of anion-exchange capacity of the DEA, TEA, EtA, DEtA memberan, the DEA membrane having higher adsorption capacity than TEA, EtA, DEtA membrane.

시각장애인 주택의 실태 및 요구도 분석에 관한연구

김상운,강병근,성기창,박광재,윤영삼,정은영 한국의료복지시설학회 2009 의료·복지 건축 Vol.15 No.1

Increasing the old and the senile disability, it is increased that the demand of barrier free house for the disabled the senior the pregnant and the young is strongly increasing recently. In this reason, this study focuses the problems of the house which is used by the Blind through the investigation of current status and tries to find out the differences between disability's demend and current design of their house. As well, through the research and analysis some cases of the residential alterations this study verifies what the demand is on each room and their need is committed correctly during the residential alterations. It is the purposes of this study finding the problems through these research and analysis Thus this study investigates houses of the Blind and finds out their house type scale and daily Iife through the statisticaI data and documentary survey and also investigates current status of their house. The basic standard for the current status and the demand analysis is researched by the barrier factors which are deducted from the former study.

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.