• Title/Summary/Keyword: failure pressure

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Effects of Increased Pulmonary Blood Flow Produced Bb Experimental left Pulmonary Artery Ligation on the Pulmonary Vascular Bed in Neonateal Goats (신생 염소에서 실험적 좌폐동맥 결찰술로 유발시킨 폐혈류량 증가가 폐혈관상에 미치는 영향)

  • 서경필
    • Journal of Chest Surgery
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    • v.23 no.6
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    • pp.1057-1066
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    • 1990
  • The possible relationship between pulmonary vascular pathologic changes and an increased pulmonary blood flow and pulmonary blood pressure has been the subject of investigation for many years. In an attempts to study the effects of increased pulmonary blood flow. long-term observations have been made in neonatal goats in which the total pulmonary vascular bed was restricted by means of ligation of left pulmonary artery, thereby diverting the total right ventricular output through the right lung. The left pulmonary artery and patent ductus arteriosus were ligated in 6 neonatal goats of under 3 weeks of age, and the goats were put to death at interval between 1 and 7 months of age. Pulmonary arterial development in both right and left lungs was studied by applying quantitative morphometric techniques, and compared with control group of goats between 1 and 6 months of age. The axial pulmonary artery and its branches were larger in the right lung than in the control group in all animals, and they were abnormally small in the left lung. In the right lung, arteries smaller than 50\ulcornerm showed abnormal increase in `% wall thickness’ in postoperative 2,3,5 and 6th months[p<0.05]. The proportion of non-muscular arteries was over 50% at postoperative 1st month in both right and left lungs, but an increase in proportion of partially muscular and wholly muscular arteries occurred thereafter. The ratio of alveoli/arteries was lower than normal in the right lung of postoperative 1st month[p<0.05], but was elevated thereafter. The failure to perfuse one pulmonary artery in neonatal goats changed growth and development of both lungs.

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Wind tunnel study of wake-induced aerodynamics of parallel stay-cables and power conductor cables in a yawed flow

  • Jafari, Mohammad;Sarkar, Partha P.
    • Wind and Structures
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    • v.30 no.6
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    • pp.617-631
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    • 2020
  • Wake-induced aerodynamics of yawed circular cylinders with smooth and grooved surfaces in a tandem arrangement was studied. This pair of cylinders represent sections of stay-cables with smooth surfaces and high-voltage power conductors with grooved surfaces that are vulnerable to flow-induced structural failure. The study provides some insight for a better understanding of wake-induced loads and galloping problem of bundled cables. All experiments in this study were conducted using a pair of stationary section models of circular cylinders in a wind tunnel subjected to uniform and smooth flow. The aerodynamic force coefficients and vortex-shedding frequency of the downstream model were extracted from the surface pressure distribution. For measurement, polished aluminum tubes were used as smooth cables; and hollow tubes with a helically grooved surface were used as power conductors. The aerodynamic properties of the downstream model were captured at wind speeds of about 6-23 m/s (Reynolds number of 5×104 to 2.67×105 for smooth cable and 2×104 to 1.01×105 for grooved cable) and yaw angles ranging from 0° to 45° while the upstream model was fixed at the various spacing between the two model cylinders. The results showed that the Strouhal number of yawed cable is less than the non-yawed case at a given Reynolds number, and its value is smaller than the Strouhal number of a single cable. Additionally, compared to the single smooth cable, it was observed that there was a reduction of drag coefficient of the downstream model, but no change in a drag coefficient of the downstream grooved case in the range of Reynolds number in this study.

Improvement of Soft Marine Clay by Preloading and Wick Drain Method (선행하중과 Wick Drain공법에 의한 연약해성광토의 개량)

  • 유태성;박광준
    • Geotechnical Engineering
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    • v.3 no.1
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    • pp.7-24
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    • 1987
  • Preloading surcharge method along with vertical drains was adopted to improve the performance of a very soft marine clay deposit. The onshore deposit, located in the Ulsan Bay area, consists of a 2 to 10m thick, very soft, highly compressible marine clay layer developed just below. the sea water level. The initial undrained shear strength of the clay layer was about 0.6 ton/m2. But, the deposit was designed after treatment to support some auxiliary facilities for a new ilo refinery plant, requiring bearing capacities of 3.6 to 5.4 ton/m2 and maximum allowablee settlement of less than 7.5cm. A total of 35, 000 wick drains Ivas installed to expedite drainage during preloading, and surcharge loads of up to 5m above the original ground level were applied in a step-by-step loading sequence to prevent ground failure by excess surcharge loads. An extensive program of field instrumentation was implemented to monitor the behavior of the clay deposit. Measurers!ends included settlements, excess pore pressure and its dissipation, ground farmer level fluctuation, and lateral movement of the so(t clay layer under the preloads. This paper describes the design concepts, construction methods and control procedures used for improvement of the clay layer. It also presents the ground behavior measured during construction, rind comparisons with theoretical predictions.

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Passive Earth Pressure Transition Behind Retaining Walls (옹벽의 변위에 따른 정지토압에서 수동토압까지의 변화)

  • 김홍택
    • Geotechnical Engineering
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    • v.3 no.2
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    • pp.55-70
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    • 1987
  • An analytical solution procedure is described to estimate the developed passive lateral earth Pressures behind a vertical rigid retaintng wall rotating about its toe into a mass of cohesionless soil. Various stases of wall rotation, starting from an at-rest state to an initial Passive state to a full Passive state, are considered in the analysis. Condition of failure defined by a modified Mohr-coulomb criterion, together with equilibrium conditions, is used to obtain the necessary equations for the solution. Using methods of stress characteristics and numerical finite difference, a complete solution within and on the boundaries of the entire solution domain is made possible. The variations of the soil shear strength and the wall friction at various depths and stages of wall rotation are also taken into account in the analysis. The results predicted by the developed method of analysis are compared with those obtained from the experimental model tests on loose and dense sand. The comparisons show good agreements at various stages of retaining wall rotation Fin- ally, results of analytical parametric study are presented to demonstrate the effects of wall fric- tion on the resultant thrust and distribution of developed lateral earth pressures.

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A Comparative Study of Outsourcing Culinary Part of Foodservice Industry Development. (외식사업발전을 위한 조리분야 아웃소싱 전략에 관한 연구 (평가측정치 개발절차를 중심으로))

  • 김기영
    • Culinary science and hospitality research
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    • v.7 no.3
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    • pp.13-34
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    • 2001
  • The case which it contracts with the dynamic result measurement system when actual outsourcing evaluation measurement is composed and then one result standard between the service supplier and the user is set, which owns jointly the expense which is reduced from that or the benefit which is created from that is increasing In the conclusion, for outsourcing management strategy of domestic foodservice industry in order to succeed, first it is accurate and examined that for what and how outsourcing should be introduced and as a result, what kind of result can be raised from that result\ulcorner Food service industry should be outsourced if you want to make more many investment in better humane resources, food & beverage-goods-security and education to provide eating-out service out of various business in food industry. When considering the actuality of the domestic foodservice industry that time it is appropriate, it sees. The foreign-brand goods which is introduced in the country are being executing in the 1ink of part management strategy. One of the most influential factor of domestic foodservice industry's management pressure is overspent management expenses, Does the namely expenses preparation effect reach which degree\ulcorner what kind of method can most decrease these expenses\ulcorner Doing grows the success and failure of the Korean foodservice industry controls result with the fact that it will operate with a big variable sees. The background which the domestic foodservice industry should introduce inevitably the outsiurcing system is to develop continuously nation foodservice industry in the way of cost curtailment of food-material, a labor cost curtailment with efficient application and synergic effect like specialty manpower utilization. The kindred competitive enterprises gradually concentrate management resource to the point ability from the present point of view which is increasing and a strategy position they secure, to prepare a competitive power, what sees it is important national industry must prepare a new paradigm. It is important to measure the result based on sales accomplishment in operation system dimension, and it is more important to appropriately apply regard of the evaluation measurement

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A Comparative Experiment on Thermal Stress Failure of Vacuum Glazing applied in Curtain Wall at Spandrel area (커튼월 스팬드럴용 진공유리의 열파손에 대한 비교실험)

  • Kim, Seung-Chul;Yoon, Jong-Ho;Shin, U-Cheol;Ahn, Jung-Hyuk
    • KIEAE Journal
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    • v.16 no.3
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    • pp.121-128
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    • 2016
  • Purpose: The vacuum glazing should constantly retain the gap in vacuum state to maintain high thermal performance. To do so, pillars are used to prevent the glazing from clinging to each other by the atmospheric pressure and therefore surface of the vacuum glazing is consistently affected by residual stress. The vacuum glazing could be applied to curtain wall systems at spandrel area to fulfill a rigorous domestic standard on U-value of the external wall. However, this can lead to high glazing temperature increase by heat concentration at a back panel and finally thermal stress breakage. This study experimentally determined weakness of the vacuum glazing systems on the thermal stress breakage and investigated effect of the residual stress. Method: The experiment first built two scale-down mock-up facilities that replicate the spandrel area in curtain wall, and then installed single low-e glass and vacuum glazing respectively. The two mock-up facilities were exposed to outside to induce the thermal stress breakage. Result: The experiment showed that the temperature occurred the thermal stress breakage was $114.4^{\circ}C$ for the single low-e glass and $118.9^{\circ}C$ for the vacuum glazing respectively. The result also showed the vacuum glazing reached the critical point earlier than the single low-e glass, which means that the vacuum glazing has high potential to occur the thermal shock breakage. In addition, the small temperature difference between two glazing indicates that the residual stress scarcely affects breakage of the vacuum glazing.

Bond Strength of Grout-Filled Splice Sleeve Considering Effects of Confinement (구속효과를 고려한 모르타르 충전식 철근이음의 부착강도)

  • Kim, Hyong-Kee;Ahn, Byung-Ik
    • Journal of the Korea Concrete Institute
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    • v.15 no.4
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    • pp.615-622
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    • 2003
  • The purpose of this study is to propose the more reasonable equation of bond strength of grout-filled splice sleeve. To accomplish this objective, total 60 full-sized specimens were tested under monotonic loading. The experimental variables are compressive strength of mortar, embedment length and size of reinforcing bars. Following conclusions are obtained; 1) If the adequacy of existing equations which estimate the bond strength of grout-filled splice sleeve are investigated, they underestimate the bond strength of grout-filled splice sleeve by 8-18%. Also the existing equations have a tendency to underestimate with decrease in the embedment length of reinforcing bars. 2) From the test result of bond failure, the equation which estimates the confining pressure of grout-filled splice sleeve was proposed by making multiple regression analyses of which independent variables are embedment length of reinforcing bars and compressive strength of mortar. This equation predicted the measured bond capacity of this test more accurately than existing equations and eliminated the deviation according to the embedment length of reinforcing bars.

Clinical characteristics of hypertensive encephalopathy in pediatric patients

  • Ahn, Chang Hoon;Han, Seung-A;Kong, Young Hwa;Kim, Sun Jun
    • Clinical and Experimental Pediatrics
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    • v.60 no.8
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    • pp.266-271
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    • 2017
  • Purpose: The aim of this study was to assess the clinical characteristics of hypertensive encephalopathy according to the underlying etiologies in children. Methods: We retrospectively evaluated 33 pediatric patients who were diagnosed as having hypertensive encephalopathy in Chonbuk National University Children's Hospital. Among the patients, 18 were excluded because of incomplete data or because brain magnetic resonance imaging (MRI) was not performed. Finally, 17 patients were enrolled and divided into a renal-origin hypertension group and a non-renal-origin hypertension group according to the underlying cause. We compared the clinical features and brain MRI findings between the 2 groups. Results: The renal group included renal artery stenosis (4), acute poststreptococcal glomerulonephritis (2), lupus nephritis (2), and acute renal failure (1); the nonrenal group included essential hypertension (4), pheochromocytoma (2), thyrotoxicosis (1), and acute promyelocytic leukemia (1). The mean systolic blood pressure of the renal group ($172.5{\pm}36.9mmHg$) was higher than that of the nonrenal group ($137.1{\pm}11.1mmHg$, P<0.05). Seizure was the most common neurologic symptom, especially in the renal group (P<0.05). Posterior reversible encephalopathy syndrome (PRES), which is the most typical finding of hypertensive encephalopathy, was found predominantly in the renal group as compared with the nonrenal group (66.6% vs. 12.5%, P<0.05). Conclusion: We conclude that the patients with renal-origin hypertension had a more severe clinical course than those with non-renal-origin hypertension. Furthermore, the renal-origin group was highly associated with PRES on brain MRI.

Overview of Pediatric Continuous Renal Replacement Therapy in Acute Kidney Injury (급성 신손상을 가진 소아의 지속적 신대체 요법)

  • Park, Se-Jin;Shin, Jae-Il
    • Childhood Kidney Diseases
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    • v.15 no.2
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    • pp.107-115
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    • 2011
  • Acute kidney injury (AKI) is associated with mortality and may lead to increased medical expense. A modified criteria (pediatric RIFLE [pRIFLE]: Risk, Injury, Failure, Loss, and End-stage renal disease) has been proposed to standardize the definition of AKI. The common causes of AKI are renal ischemia, nephrotoxic medications, and sepsis. A majority of critically ill children develop AKI by the pRIFLE criteria and need to receive intensive care early in the course of AKI. Factors influencing patient survival (pediatric intensive care unit discharge) are known to be low blood pressure at the onset of renal replacement therapy (RRT), the use of vasoactive pressors during RRT, and the degrees of fluid overload at the initiation of RRT. Early intervention of continuous RRT (CRRT) has been introduced to reduce mortality and fluid overload that affects poor prognosis in patients with AKI. Here, we briefly review the practical prescription of pediatric CRRT and literatures on the outcomes of patients with AKI receiving CRRT and associations among AKI, fluid overload, and CRRT. In conclusion, we suggest that an increased emphasis should be placed on the early initiation of CRRT and fluid overload in the management of pediatric AKI.

Development of an Ultra-Slim System in Package (SiP)

  • Gao, Shan;Hong, Ju-Pyo;Kim, Jin-Su;Yoo, Do-Jae;Jeong, Tae-Sung;Choi, Seog-Moon;Yi, Sung
    • Journal of the Microelectronics and Packaging Society
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    • v.15 no.1
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    • pp.7-18
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    • 2008
  • This paper reviews the current development of an ultra-slim SiP for Radio Frequency (RF) application, in which three flip chips, additional passive components and Surface Acoustic Wave (SAW) filters are integrated side-by-side. A systematic investigation is carried out for the design optimization, process and reliability improvement of the package, which comprises several aspects: a design study based on the 3D thermo-mechanical finite element analysis of the packaging, the determination of stress, warpage distribution, critical failure zones, and the figuration of the effects of material properties, process conditions on the reliability of package. The optimized material sets for manufacturing process were determined which can reduce the number of testing samples from 75 to 2. In addition the molded underfilling (MUF) process is proposed which not only saves one manufacturing process, but also improves the thermo-mechanical performance of the package compared with conventional epoxy underfilling process. In the end, JEDEC's moisture sensitivity test, thermal cycle test and pressure cooker tests have also been carried out for reliability evaluation. The test results show that the optimized ultra-slim SiP has a good reliability performance.

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