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

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.

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.

국부의치 Framework용 비귀금속 합금의 경도에 관한 연구

金在道,金炳植 대구산업정보대학 1997 논문집 Vol.11 No.2

The hardness of four kinds of cr-co alloys and one kind of Titanium alloy, which are widely used as partial denture framework these days, were measured and the following result were obtained. The tested alloys of cr-co alloy are Vitallium alloy (AUSTENNAL Co., U.S.A), and Biosil alloy (DEGUSSA Co., GERMANY), and Wironium extra-hard alloy (BEGO Co., GERMANY), and Ticonium alloy (TICONIUM Co., U.S.A), and Titanium alloy are pure titanium. (OHARA Co., JAPAN). 1. The cr-co alloy showed higher value (331.46±2.73Hv-376.74±2.34Hv) (RHN-30N : about 53.72-57.88) than the pure titanium alloy one (211.76 ± 11.2Hv) (RHN-30N value : about 36.66). 2. The hardness value (376.74+2.34Hv) (RHN-30N : 57.88) of experimental Ⅱ alloy was the highest. 3. The hardness value (211.76±11.2Hv) (RHN-30N : 36.66) of experimental Ⅴ alloy was the lowest. 4. These results suggested that the method of bench cooling was more effective.

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.

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.

가교제를 첨가시킨 BSA고정막의 합성 및 특성

김재훈,김민,김병식 한국공업화학회 2003 응용화학 Vol.7 No.1

Bovine serum albumin(BSA) as a chiral ligand was captured uniformly throughout a porous hollow-fiber membrane at a level of 250mg/g by the polymer chains grafted onto the membrane. Subsequetly, crosslinking of BSA with a 0.05%(w/w) of glutaraldehyde in a Tris-HCL buffer (pH 8) for 5 h was effective in stabilizing the amount of BSA immobilized at a level of 200 mg/g. A solution of 이-Tryptophan in Tris-HCI buffer asa mobile phasa permeated the crosslinked-BSA multilayered membrane. Therefore on experimentation is BAS immobilized hollow fiber is applicable for the chiral separation of enantiomers in a mobile phase with various pH values and organic modifiers.

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.

전신마취하에 치료한 환자에 대한 실태조사

김하나,백병주,김재곤,권병우,양연미 大韓小兒齒科學會 2006 大韓小兒齒科學會誌 Vol.33 No.2

소아환자를 진료하다 보면 불안과 공포가 극도로 심하여 일반적인 행동조절법으로는 양질의 치과치료가 불가능한 상황에 자주 접하게 된다. 음성조절과 신체 속박 또는 입 가리기 등의 강압적이고 물리적인 방법을 사용하여도 역시 치료결과가 만족스럽지 않고 이러한 경우 환자와 보호자에게 가해지는 정신적인 상해는 결코 무시할 수 없다. 따라서 행동 조절의 어려움과 치과 질환의 심각성 등으로 인해 전신마취하의 치과치료가 필요한 경우가 많으며 이 경우 전신마취는 행동조절법의 하나로 간주될 수 있다. 치과전신마취는 비용이 많이 드는 것과 적지만 있을 수 있는 부작용의 위험성을 가지고 있다. 그러나 환자의 내원 횟수를 줄일 수 있고 치과치료에 대한 부정적인 행동반응을 유발하지 않아 의사와 환자의 스트레스를 줄일 수 있으며 양질의 진료가 가능하다는 점에서 장점을 갖는다. 이번 실태조사는 2000년 12월부터 2005년 4월까지 전북대학교 치과병원 소아치과에서 전신마취하에 광범위한 치과치료를 받은 200여명의 환자를 대상으로 하여 나이, 성별 등의 인적 사항, 전신마취가 필요했던 이유, 전신마취시간, 치료의 종류, 전신마취횟수 등에 관하여 조사하였다. Dental caries in children has declined over the past few decades. However, Certain populations of children experience high levels of dental disease. To perform the highest quality dental care for the pediatric patient, the practitioner may need to use pharmacological means to obtain a quiescent, cooperative patient. Furthermore, complex treatment can impose high demands on the very young, making use of general anesthesia the preferred approach for some patients. General anesthesia is widely used to provide comprehensive dental treatment for children in USA and Europe and Scandinavia etc. Parental and patient satisfaction following completion of dental care under general anesthesia is reportedly high. Dental general anesthesia has disadvantage that it is expansive and carries a small but significant risk of mortality. However, It has the advantage of permitting treatment at a single visit, allowing immediate relief of pain and requiring little or no cooperation from the child. Rampant caries was the major indication for use of general anesthesia in the youngest age group or medically compromised patients. This study describe the characteristics of patient receiving comprehensive dental treatment under general anesthesia at the pediatric dentistry of Chonbuk National University Hospital in Jeonju. Korea in the 4year period between December 2001 and April 2005.