• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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• pp.221-226
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• 1994

A safety evaluation of cable tunnel, which is a concrete box structure with telecommunication facilities in it, exposed to fire is given. The immediate field observation was performed to find out any sign of sudden structural failure. In some region, where the fire intensity was heavy, the spalling of concrete cover in upper slab occurred. Next, more careful investigation was done with proper non-desturctive testing methods and structural analysis taking into account the changes in material properties due to fire. It seems that there is no severe damage on concrete, reinforcements and over all structural system.

• Journal of Advanced Marine Engineering and Technology
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• 제22권1호
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• pp.92-99
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• 1998

Unsteady flow problems created by hydraulic transients in pipeline systems with pump are of significant importance because they can cause excessive pressure, cavitation, vibration and noise. In this paper, an analysis of transient flow for the pump pipelines is developed by means of the characteristic method. The calculated results of the program to simulate water hammer due to sudden valve closure in a simple pipeline are compared with those of the analytical method. Expecially the water hammer due to power failure in pump pipeline system with surge tank was simulated. As the results, both the upsurge and the downsurge along the pipeline are reduced.

• 콘크리트학회논문집
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• 제16권5호
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• pp.667-675
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• 2004

본 논문은 CFRP 격자 보강재로 보강한 콘크리트 슬래브의 파괴형태와 보강설계기준에 대한 연구이다. 실험 연구에서 채택한 시험변수로는 CFRP 격자 보강재의 양, 보강 모르타르의 깊이, 앵커핀의 유무, 압축부 보강 등이다. 연구에 의하면 CFRP 격자 섬유 보강량에 따라 파괴형태가 다르게 나타났는데 낮은 보강수준에서는 FRP 격자의 인장 파단파괴를 보였고 보통의 보강정도에서는 격자층 계면전단파괴가 발생하였다. 높은 보강량을 가진 슬래브에서는 사인장전단파괴 형태를 나타냈다. 보강 효과는 FRP 격자 보강재의 양이 증가할수록 증대하였으나 취성 전단파괴에 의해 연성은 감소되었다. 따라서 FRP 격자 보강량을 제한함으로써 갑자기 하중 지지력을 상실하는 전단파괴를 피할 수 있다. 파괴형태 중 CFRP 파단파괴가 바람직한데 그 이유는 섬유파단 후에도 극한상태에서 보강 전 슬래브의 하중지지력과 연성을 가지고 있기 때문이다. 마지막으로 본 논문은 CFRP 격자섬유보강설계기준과 과정을 제시하고 있다.

• 생명과학회지
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• 제20권5호
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• pp.639-643
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• 2010

비육우의 공장, 회장 및 결장의 특징적 괴사 출혈성 장염 증상은 폐사 증후군과 관련이 있는 것으로 인식되고 있다. 특히 젖먹이 송아지들이 폐사 증후군에 가장 영향을 받는데, 포유시 송아지에게 과식을 시키거나, 비위생적 초유 급유, 체온 하강 및 스트레스는 장독혈증 발생의 원인들이다. 2006년 7월 중 경북 영천 지역에서 축우의 폐사가 발생하였다. 식욕부진, 의기소침, 간헐적인 설사 및 경미한 호흡 곤란을 제외하고는 특별한 임상 증상은 없었으나, 조직학적 소견에 의하면, 심장, 신장, 간, 비장 및 임파선을 포함한 각종 기관에서 globular leukocytes 의 침윤뿐 아니라 핵내 봉입체가 현저하게 나타났다. 비장과 림프조직에서는 림프 괴사와 림프구 괴사로 인한 'starry sky appearance'를 나타내었다. 소장 점막 하에서는 다량의 globular leukocytes와 호산 구의 침윤과 함께 호 염기성 세포 집단이 관찰되었다. 봉입체가 있는 소장 조직의 단면은 그램 염색에 대해 조직 화학적으로 양성 반응을 나타내었다. 결론적으로, 비축우의 폐사 원인은 조직학적 및 조직화학적 분석 결과를 근거로 Clostridium perfringens D 형균에 의한 장독혈증으로 진단되었다.

• 상하수도학회지
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• 제21권4호
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• pp.385-394
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• 2007

The objective of this study was to estimate social cost on rehabilitation of existing water pipes by investigating the willingness-to-pay (WTP) of residents at INJE County to avoid the loss and inconvenience of transportation and business resulting from the sudden failure and leaks of old water pipes. Contingent valuation method was used through conducting survey to 180 residents in Inche County, with questions of double-bounded dichotomous choice. The resulting WTP of residents at Inche was 7,682 won/month/household. The annual social cost could be estimated as 960 million won, which might be caused by the failure of the old water pipes at INJE County.

• Journal of Chest Surgery
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• 제24권9호
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• pp.861-869
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• 1991

From August, 1986 to December, 1989, mitral valve replacement was performed in 93 patients. Of the valve implanted, 42 were Duromedics, 35 St. Jude Medical, 15 Carpenter-Edwards and 1 Ionescu-Shiley. The hospital mortality rate was 3.2%[3 patients] and the late mortality rate was 4.3% [4 patients]. The causes of hospital death were LV rupture in 1, renal failure in 1 and hypoxic brain damage in l. The causes of late death were congestive heart failure in 1 and sudden death in 3. Follow-up was done on 78 surviving patients; mean follow-up period was 29.22$\pm$9.09 months. The actual survival rate was 91.8% at 4 years. We concluded, therefore, that good clinical results could be achieved with mitral valve replacement in short-term follow-up, and long-term follow-up is also necessary.

• 콘크리트학회논문집
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• 제11권6호
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• pp.113-119
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• 1999

Fatigue failure is a phenomenon such that structures under cyclic service load is failed by sudden brittle manner. Therefore, in order to obtain structures safety against the fatigue failure during their service lifes, fatigue characteristics should be considered for design and analysis of the structures. As stress range of prestressed (PS) tendons, which governs fatigus characteristic of prestressed concrete (PSC) structures, increases with increased use of partial prestressig, it is more necessary to consider fatigue characteristics of PS tendons. In this paper, direct-tension fatigue experiments with special specimen-setting devices are carried out to obtain fatigue characteristics of domestic low relaxation PS strands having different diameters and PS strands connected with coupler. Then, allowable stress range of fatigue for PSC beams using low relaxation strands are presented for the fatigue examination of prestressed concrete beams applied cyclic loading.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.544-547
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• 2004

Predicting the failure modes of reinforced concrete corbels is difficult because the reinforced concrete corbels show the shapes of sudden shear failures at even slight deflection. For this reason, an exact analysis method is demanded highly. In this study, the validity of the grid softened strut-tie model method suggested for concrete member analysis was examined through the ultimate strength evaluation of the reinforced concrete corbels tested to failure. The evaluated ultimate strengths by the grid softened strut-tie model method were compared with those by the ACI 318-02 and the softened strut-tie model method.

• Journal of Chest Surgery
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• 제26권3호
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• pp.228-233
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• 1993

Patients with anomalous connection of the left coronary artery to the pulmonary artery are at risk for myocardial infarction, and early or sudden death. Between 1986 to 1992, a total of 4 of these patients underwent surgical intervention with various operative techniques at our institution. Age at operation ranged from 2 months to 43 years. Three infant patients had congestive heart failure, 2 of them had mitral regurgitaion, and 1 had ST-T change on elctrocardiogram. Operative techniques included direct coronary artery transfer to the aorta[n=2], intrapulmonary tunnel from the aortopulmonary window[n=1], coronary artery bypass using saphenous vein[n=1]. One deaths occured at 2 weeks after direct coronary arterial transfer due to respiratory failure caused by Respiratory Syncitial virus pneumonia. Supravalvar pulmoanry stenosis occured after intrapulmoanry tunnel. We recommend direct aortic implatation of the anomalous coronary artery at the time of diagnosis. Intrapulmonary tunnel from aortopulmonary window or subclavian-coronary anastomosis could be alternatives in whom aortic implantation is not feasible anatomically.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.534-541
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• 2004

The modeling of crack initiation and propagation is very important for the failure analysis of concrete. The cracking process in concrete is quite different from that of other materials, such as metal and glass, in that it is not a sudden onset of new free surface but a continuous forming and connecting of microcracks. The failure process of concrete by cracking causes irreversible deformations and stiffness degradation. Those phenomenon can be modeled using plasticity and damage theory in macroscopic aspect. In this study, a plastic-damage model based on homogenized crack model considering velocity discontinuity and damage variable which is a function of plastic strain is proposed for fracture analysis of concrete. Finally, the plastic-damage model is verified with experimental data.