• Title/Summary/Keyword: Rupture rate

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The Effects of Maternal HBs antigenemia on the Neonatal Health (산모(産母)의 B형 간염(肝炎) Virus 보유(保有)가 신생아(新生兒) 건강(健康)에 미치는 영향(影響))

  • Park, Jung-Han;Yoon, Sung-Do;Kim, Chang-Youn;Lee, Sung-Kwan
    • Journal of Preventive Medicine and Public Health
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    • v.17 no.1
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    • pp.47-55
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    • 1984
  • To study the risk factors associated with maternal HBsAg carrier and the effects of maternal HBs antigenemia on the neonatal health, sera of 729 pergnant women admitted to the Keimyung University Hospital for delivery during the period of February 1-May 30. 1982 were tested for HBsAg by RPHA method and for anti-HBs by PHA method. Among them 43 women (5.9%) had HBsAg and 246 women (33.7%) had anti-HBs giving an infection rate of 39.6%. The interview data for 43 HBsAg positive mothers and randomly selected 210 HBsAg negative mothers showed a statistically significant association between acupuncture history and HBsAg positive rate (p<0.005) which suggest that acupuncture might have contributed significantly to the propagation of viral hepatitis in Korea. The living standard of HBsAg positive mothers was generally lower than that of HBsAg negative mothers which supports the hypothesis that environmental factors are associated with viral hepatitis B infection. None of the 43 neonates born to HBsAg positive mothers had HBsAg in their cord blood. Three months after birth, 35 out of 43 infants were retested and only one infant became HBsAg positive. At six months of age, 32 out of 35 infants were retested and none of them were HBsAg positive except the same infant who was positive at three months. Among 20 control infants of HBsAg negative mothers, all of them were HBsAg negative at three and six months follow-up. These findings are not consistent with the supposition that perinatal infection is a main route of viral hepatitis B transmission in south-east Asia including Korea. HBsAg positive mothers had significantly higher rate of premature delivery (27.9%) than HBsAg negative mothers (11.7%) (p<0.05). Also, the low birthweight incidence rate was higher among HBsAg positive mothers (23.3%) than negative mothers (14.1%) but this was not statistically significant (P=0.16). The premature rupture of membrane was more frequent among HBsAg positive mothers (25.5%) than negative mothers (11.1%) (p<0.05). There were no significant differences in the stillbirth rate and incidence of congenital anomalies between HBsAg positive and negative groups. It was not clarified in this study due to small sample size whether higher incidence of premature delivery and premature rupture of membranes among HBsAg positive mothers was due to HBs antigenemia per so or their lower living standard than HBsAg negative mothers.

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Evaluation of Monkman-Grant Parameters for Type 316LN and Modified 9Cr-Mo Stainless Steels

  • Kim, Woo-Gon;Kim, Sung-Ho;Ryu, Woo-Seog
    • Journal of Mechanical Science and Technology
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    • v.16 no.11
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    • pp.1420-1427
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    • 2002
  • The Monkman-Grant (M-G) and its modified parameters were evaluated for type 316LN and modified 9Cr-Mo stainless steels prepared with minor element variations. Several sets of creep data for the two alloy systems were obtained by constant-load creep tests in 550~650$\^{C}$ temperature range. The M-G parameters, m, m', C, and C' were proposed and discussed for the two alloy systems. The m value of the M-C relation was 0.90 in type 316LN steel and 0.84 in modified 9Cr-Mo steel. The m' value of the modified relation was 0.94 in type 316LN steel and 0.89 in 9Cr-Mo steel. Although creep fracture modes and creep properties between type 316LN and modified 9Cr-Mo steels showed a basic difference, the M-G and its modified relations demonstrated linearity quite well. The m' of modified relation almost overlapped regardless of the creep testing conditions and chemical variations in the two alloy systems, and the parameter m' was closer to unity than that of the M-G relation.

EXPERIMENTAL STUDY ON THE HEALING PROCESSES AFTER MICROVASCULAR ANASTOMOSES;Light and Scanning electron microscopic observations (미세혈관 문합수술후 치유과정에 관한 실험적 연구)

  • Yoon, Jae-Hyun;Lee, Eun-Joo
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.12 no.1
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    • pp.72-81
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    • 1990
  • Because failure of microvascular flap grafting has sometimes been attributed to vascular obstruction in the anastomotic site, this study investigated the healing process after microvascular anastomoses. The healing process of anastomotic sites were observed by the use of the light and the scanning electron microscope after microvascular anastomoses of the right common carotid artery in rats. The experimental animals were sacrificed on the 4th day, 1st, 2nd, 4th and 6th week. Throughout the whole experimental period, arterial patency rate was 78% (11/14). At the early stage, it was possible to recognize histologically disappearance of endothelial cell and rupture of part of the media. Subintimal hyperplasia and the growth of media appeared around the suture line at the 2nd week. Endothelial cell regeneration occurred and the depth of vessel wall was normalized at the 4th week. By the scanning electron microscope, at the early stage, the anastomotic site was covered with many platelets, red blood cells, fibrins and macrophages. At the 4th week, the insertion site of the thread was completely covered with normal endothelial cells which were parallel to longitudinal axis of vessels and complete reendothelialization over the anastomotic site seemed to take about 6th week.

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Stress Corrosion Cracking Behavior under Cavitation Erosion-Corrosion in Sea Water-Part (II) (해수환경중 캐비테이션 침식-부식 하에서의 응력부식균열 거동 (II))

  • 안석환;임우조
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.36 no.2
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    • pp.139-146
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    • 2000
  • Cavitation can occur in pipes when liquid is moving at high velocity, especially at pittings where the smooth bore of the pipe is interrupted. The effect is usually to produce pitting on the downstream side of the turbulence. However, stress corrosion cracking behavior under cavitation erosion-corrosion was neatly unknown. In this study, therefore, some were investigated of stress corrosion cracking behavior, others were stress corrosion cracking behavior under cavitation erosion-corrosion of water injection. And datas obtained as the results of experiment were compared between the two. Mainresult obtained are as follows: 1) Stress corrosion cracking growth rate of heat affected zone under cavitation erosion-corrosion becomes most rapid, and stress intensity factor $K_1$becomes most high. 2) Stress corrosion cracking growth mechanism by cavitation erosion-corrosion is judgement on the strength of the film rupture model and the tunnel model. 3) The range of potential as passivation of heat affected zone is less noble than that of base metal, and that value is smaller. 4) Corrosion potential under cavitation erosion-corrosion in loaded stress is less noble than that of stress corrosion, and corrosion current density is higher.

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Tests on Cementless Alkali-Activated Slag Concrete Using Lightweight Aggregates

  • Yang, Keun-Hyeok;Mun, Ju-Hyun;Lee, Kang-Seok;Song, Jin-Kyu
    • International Journal of Concrete Structures and Materials
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    • v.5 no.2
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    • pp.125-131
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    • 2011
  • Five all-lightweight alkali-activated (AA) slag concrete mixes were tested according to the variation of water content to examine the significance and limitation on the development of cementless structural concrete using lightweight aggregates. The compressive strength development rate and shrinkage strain measured from the concrete specimens were compared with empirical models proposed by ACI 209 and EC 2 for portland cement normal weight concrete. Splitting tensile strength, and moduli of elasticity and rupture were recorded and compared with design equations specified in ACI 318-08 or EC 2, and a database compiled from the present study for ordinary portland cement (OPC) lightweight concrete, wherever possible. Test results showed that the slump loss of lightweight AA slag concrete decreased with the increase of water content. In addition, the compressive strength development and different mechanical properties of lightweight AA slag concrete were comparable with those of OPC lightweight concrete and conservative comparing with predictions obtained from code provisions. Therefore, it can be proposed that the lightweight AA slag concrete is practically applicable as an environmental-friendly structural concrete.

A Probabilistic based Systems Approach to Reliability Prediction of Solid Rocket Motors

  • Moon, Keun-Hwan;Gang, Jin-Hyuk;Kim, Dong-Seong;Kim, Jin-Kon;Choi, Joo-Ho
    • International Journal of Aeronautical and Space Sciences
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    • v.17 no.4
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    • pp.565-578
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    • 2016
  • A probabilistic based systems approach is addressed in this study for the reliability prediction of solid rocket motors (SRM). To achieve this goal, quantitative Failure Modes, Effects and Criticality Analysis (FMECA) approach is employed to determine the reliability of components, which are integrated into the Fault Tree Analysis (FTA) to obtain the system reliability. The quantitative FMECA is implemented by burden and capability approach when they are available. Otherwise, the semi-quantitative FMECA is taken using the failure rate handbook. Among the many failure modes in the SRM, four most important problems are chosen to illustrate the burden and capability approach, which are the rupture, fracture of the case, and leak due to the jointed bolt and O-ring seal failure. Four algorithms are employed to determine the failure probability of these problems, and compared with those by the Monte Carlo Simulation as well as the commercial code NESSUS for verification. Overall, the study offers a comprehensive treatment of the reliability practice for the SRM development, and may be useful across the wide range of propulsion systems in the aerospace community.

Surgical Treatment of the Abdominal Aortic Aneurysm (복부 대동맥류의 외과적 치료)

  • 황석하
    • Journal of Chest Surgery
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    • v.26 no.5
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    • pp.355-359
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    • 1993
  • Ten consecutive patients with abdominal aortic aneurysm were treated in Chungnam National University Hospital from May of 1985 to June of 1993. Pulsating palable mass was the most common first sign [7 patients]. The ratio of male to female was 8:2. The age ranged from 53 to 73 years with mean age of 65 years. The etiology and location of the aneurysm was atherosclerosis and infrarenal aorta in all. Dacron graft interposition [straight graft-1, bifurcation graft-7] and wrapping with aneurysmal sac were performed in 8 patients. In one patient with infected abdominal aortic aneurysm, we performed aneurysmectomy and left axillo-bifemoral bypass with 8 mm PTFE graft. And in another patient with complete thrombotic obstruction of infrarenal aortic aneurysm, we performed the suturing of the proximal part of the abdominal aortic aneurysm and aorto-bifemoral bypass with 18 x 9 mm PTFE graft. There was one operative death with the mortality rate of 11 % and 8 complications in 4 patients; ARF[2], duodenal ulcer[1], mechanical ileus[1], genitourinary dysfunction[2] and wound infection with abdominal abscess[1]. Because of the high operative mortality after rupture of the aneurysm, we think it is better to operate on early at the diagnosis of abodominal aortic aneurysm is made.

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Successful Management of Delayed Esophageal Rupture with T-Tube Drainage Using Video-Assisted Thoracoscopic Surgery

  • Do, Young Woo;Lee, Chang Young;Lee, Sungsoo;Kim, Ha Eun;Kim, Bong Jun;Lee, Jin Gu
    • Journal of Chest Surgery
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    • v.49 no.6
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    • pp.478-480
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    • 2016
  • Spontaneous perforation of the esophagus after forceful vomiting is known as Boerhaave syndrome, a rare and life-threatening condition associated with a high rate of mortality. The management of Boerhaave syndrome is challenging, especially when diagnosed late. Herein, we report the successful management of late-diagnosed Boerhaave syndrome with T-tube drainage in a 55-year-old man. The patient was transferred to our institution 8 days after the onset of symptoms, successfully managed by placing a T-tube, and was discharged on postoperative day 46 without complications.

Endovascular Treatment of a Ruptured Posterior Inferior Cerebellar Artery Aneurysm during Pregnancy

  • Kim, Ki Dae;Chang, Chul Hoon;Choi, Byung Yon;Jung, Young Jin
    • Journal of Korean Neurosurgical Society
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    • v.55 no.5
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    • pp.273-276
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    • 2014
  • Aneurysmal subarachnoid hemorrhage (SAH) during pregnancy is quite rare, however it has a high maternal mortality rate. A pregnant woman in the 16th gestational week was admitted to our hospital with a drowsy level of consciousness. A brain magnetic resonance (MR) image showed hemorrhage on the prepontine cistern, and both sylvian fissures, and MR angiography and cerebral digital subtraction angiography demonstrated an aneurysm at the left posterior inferior cerebellar artery (PICA). We performed endovascular coil embolization attempting to minimize radiation exposure. She was discharged with no neurologic deficit and delivered a healthy baby by cesarean section at the 38th week of gestation. This case study reported the shortest gestational period and this is the first report on an aneurysmal rupture arising from PICA which was treated using an endovascular method. Using an appropriate technique for reduced radiation exposure to the fetus and limited alterations in maternal-fetal physiology, endovascular coil embolization could guarantee good results in treatment of aneurysmal SAH in pregnant women.

Mechanical properties and adiabatic temperature rise of low heat concrete using ternary blended cement

  • Kim, Si-Jun;Yang, Keun-Hyeok;Lee, Kyung-Ho;Yi, Seong-Tae
    • Computers and Concrete
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    • v.17 no.2
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    • pp.271-280
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    • 2016
  • This study examined the mechanical properties and adiabatic temperature rise of low-heat concrete developed based on ternary blended cement using ASTM type IV (LHC) cement, ground fly ash (GFA) and limestone powder (LSP). To enhance reactivity of fly ash, especially at an early age, the grassy membrane was scratched through the additional vibrator milling process. The targeted 28-day strength of concrete was selected to be 42 MPa for application to high-strength mass concrete including nuclear plant structures. The concrete mixes prepared were cured under the isothermal conditions of $5^{\circ}C$, $20^{\circ}C$, and $40^{\circ}C$. Most concrete specimens gained a relatively high strength exceeding 10 MPa at an early age, achieving the targeted 28-day strength. All concrete specimens had higher moduli of elasticity and rupture than the predictions using ACI 318-11 equations, regardless of the curing temperature. The peak temperature rise and the ascending rate of the adiabatic temperature curve measured from the prepared concrete mixes were lower by 12% and 32%, respectively, in average than those of the control specimen made using 80% ordinary Portland cement and 20% conventional fly ash.