• Structural Monitoring and Maintenance
• /
• 제2권1호
• /
• pp.49-64
• /
• 2015

This paper presents a method for assessing the risk of wave run-up and overtopping of existing coastal defences and for analysing the probability of failure of the structures under future hydraulic conditions. The recent UK climate projections are employed in the investigations of the influence of changing environments on the long-term performance of sea defences. In order to reduce the risk of wave run-up and overtopping caused by rising sea level and to maintain the present-day allowances for wave run-up height and overtopping discharge, the future necessary increase in crest level of existing structures is investigated. Various critical failure mechanisms are considered for reliability analysis, i.e., erosion of crest by wave overtopping, failure of seaside revetment, and internal erosions within earth sea dykes. The time-dependent reliability of sea dykes is analysed to give probability of failure with time. The results for an example earth dyke section show that the necessary increase in crest level is approximately double of sea level rise to maintain the current allowances. The probability of failure for various failure modes of the earth dyke has a significant increase with time under future hydraulic conditions.

• 한국해양공학회지
• /
• 제16권4호
• /
• pp.7-12
• /
• 2002

This study is aimed to find the scouring mechanism at the toe of rubble mound structures. To investigate the characteristics of scouring in front of the structure, experiments were performed with regular waves in a 2-D flume. The results of this study are as follows. 1) It can be said the characteristics of incident wave causes rolling and sliding of armour block. The difference of wave pressure on the slope, internal flow as well as settlement of armour block due to the weight cause scouring. 2) It is observed that scouring depth at the toe increased when wave height or period increased. The location of ultimate scouring and deposition depth moved seaward when wave period increased. 3) The failure of rubble mound structure was caused by waves or scouring. Failure by erosion increased with high waves and long waves. 4) Using surf-similarity parameter including characteristics of incident waves and structure, scouring and deposition pattern were found and their limit was formulated.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.90-95
• /
• 2003

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. In pipes of energy plants, sometimes, the local wall thinning may result from severe erosion-corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale welded and unwelded carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. The observed failure modes were divided into four types; ovalization, crack initiation/growth after ovalization, local buckling and crack initiation/growth after local buckling. Also, the strengths of welded and unwelded piping system with local wall thinning were evaluated.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2007년도 학술발표회 논문집
• /
• pp.1249-1253
• /
• 2007

제방은 제내지에 거주하는 인간의 재산과 삶을 방어하고, 홍수를 제어하는 가장 기본적인 수공구조물이다. 제방파괴 원인은 월류, 활동, 침식, 그리고 침투 등으로 분류되어 질 수 있다. 특히 간극수압에 의해 발생하는 침투는 제방 내부침식(internal erosion) 및 파이핑(piping) 등을 야기함으로서 제방파괴를 유도한다. 침투에 의한 제방파괴는 월류나 침식에 의한 제방파괴 유형보다 상대적으로 적으나, 다른 제방파괴 원인을 더욱 활성화 시키는 인자로 작용한다. 도시하천의 경우 높은 치수안전도를 적용하여 제방을 축조함에 따라 월류에 의한 붕괴보다 강우와 하천수의 복합요인에 의한 침투파괴가 중요한 문제로 대두되고 있다. 본 연구에서는 침투와 활동에 대한 안전성을 확보할 수 있는 침투보강기법인 단면확대기법에 대한 적용성 및 유의사항을 수치모의를 통해 검토하였다. 제방 비탈면 경사를 1:2 확대할 경우, 침투유속이 70 %정도 감소되는 것을 확인하였다. 그러나 단면확대기법은 홍수시 통수능과 제내지의 부지 확보 문제 등을 고려하여 적용하여야 하며, 도시하천에서 단면확대기법을 적용하는 데는 일정부분 한계를 가질 것으로 판단된다.

• 한국임상수의학회지
• /
• 제12권1호
• /
• pp.853-860
• /
• 1995

Two cases of guttural pouch mycosis in race horses were observed for clinical and pathological aspects of the disease to investigate etiology and pathogenesis of dysphagia and epistaxis of the horse. In case 1 showing prolonged dysphagic sign a diphtheritic membrane was confined to the guttural pouch involved with neuritis of the glossopharyngeal nerve due to fungal penetration. The other horse showing fatal recurrent epistaxis had lesion of mycetoma invading the internal carotid artery to provoke erosion of the artery. An Aspergillosis sp. was isolated from the guttural pouches of the two horses and identified as A nidulans.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2010년도 제35회 추계학술대회논문집
• /
• pp.257-260
• /
• 2010

고체 추진기관 연소관 내열재의 숯 및 삭마 두께를 예측하기 위한 방법을 제시하였다. 내열재 두께를 계산하기 위해서는 열 및 구조 경계조건을 정확히 알아야 한다. 제안된 방법은 연소관에서 복사, 대류 및 $Al_2O_3$ 조건에서 내열 고무의 열분해 현상을 규명하는데 매우 유용하다. 간단하고 빠르게 고무계 내열재를 초기에 설계하기 위하여 단순화된 수식 과 실험이 사용되었다. 연소관 후방 돔 부위의 숯 및 삭마 두께를 예측하는데 이용이 가능하며 실제 연소 시험을 통하여 적용 가능성을 확인하였다.

• 한국임상수의학회지
• /
• 제26권4호
• /
• pp.340-343
• /
• 2009

3살령의 중성화 하지 않은 암컷 풍산개가 4개월 동안의 전신 항생제와 글루코 코르티코이드 치료에 반응하지 않는 미란성의 발적을 동반한 피부염을 주증상으로 내원하였다. 신체검사상 귀끝, 콧잔등과 앞다리에서 가피, 미란, 탈모가 관찰되었으며, 농포의 세포학적 검사에서 원형의 극세포해리성 각질세포들이 비퇴행성의 호중구, 호산구와 함께 관찰되었다. 조직병리학적 검사 결과, 표피내 농포에는 다수의 호중구, 소수의 호산구와 고립되거나 군집되어있는 해리성 극세포가 포함되어 있었다. 본 환자는 병력, 임상증상, 세포학적, 조직병리학적 검사를 통해 낙엽성 천포창으로 진단되었으며, 피부병변은 사이클로스포린의 경구 투약으로 개선되었다. 이 증례는 면역 억제제인 사이클로스포린의 단독 사용으로 개에서의 낙엽성 천포창을 치료 관리 할 수 있다는 것을 입증하였다.

• IMMUNE NETWORK
• /
• 제15권3호
• /
• pp.135-141
• /
• 2015

Dysfunction of gut immune regulation is involved in mucosal damage in inflammatory bowel disease (IBD). However, there is still no efficacious immune-regulator for the treatment of IBD. Alloferon is a novel immune-modulatory peptide that was originally isolated from infected insects. It shows anti-inflammatory effects by the regulation of cytokine production by immune cells and their activities. Therefore, we investigated the effect of alloferon in a mouse model of colitis using dextran sulfate sodium (DSS). Colitis was induced by administration of DSS in drinking water for 7 consecutive days. It was confirmed by the presence of weight loss, diarrhea, hematochezia, and colon contraction. Alloferon was injected 4 days after DSS administration. We found that alloferon improved the pathogenesis of IBD based on the reduced disease activity index (DAI) and colon contraction. Edema, epithelial erosion, and immune cell infiltration were found in mice administered DSS, but the phenomena were reduced following alloferon treatment. The plasma level of IL-6, a classical pro-inflammatory cytokine in colitis, was also decreased by alloferon. Moreover, alloferon inhibited the TNF-${\alpha}$-induced degradation and phosphorylation of $I{\kappa}B$ in Colo205 colon cancer cells. Taken together, these results show that alloferon has anti-inflammatory effects and attenuates DSS-induced colitis.

• 동의생리병리학회지
• /
• 제23권3호
• /
• pp.639-644
• /
• 2009

The aim of this study was carried out to investigate the protective effect of Rhizoma Dioscoreae on the gastric mucosal lesions induced by alcohol in rats. Experimental groups were treated by oral infusion with Rhizoma Dioscoreae extract at the dose of 0.03465 g/ml(OA-RD1 group), 0.0693 g/ml(OA-RD2 group), and 0.1386 g/ml(OA-RD3 group), while D.W group was administrated with the distilled water and control group did not pretreated. Experimental groups pretreated for 14 days, and given orally 1 ml of 75% alcohol two times(30min interval). The animals were killed 1hr 30min after alcohol treatment, and measured rats body weight, absolute stomach weight, relative stomach weight, SOD activity, glutathione peroxidase(GPx) activity, observed gastric mucosal lesions. The body weight was unremarkable changed. In once as dose intake group's absolute stomach weight was increased and In once as dose intake group, twice as dose intake group's relative stomach weight was increased. SOD activity, glutathione peroxidase activity in twice as dose intake group is remarkably increased. Light microscopy Observations of congestion, hemorrhage, and erosion in gastric mucosal lesions were shown severely in control group than OA-RD1, OA-RD2, OA-RD3. These results suggest that the proposed gastroprotective effect may involve activation of antioxidant effect. And Twice as dose is especially effective.

• 대한기계학회논문집A
• /
• 제27권1호
• /
• pp.8-17
• /
• 2003

Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear Power Plant. In Pipes of energy Plants, sometimes, the local wall thinning may result from severe erosion-corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization. crack initiation/growth after ovalization, local buckling and crack initiation/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated.