• Steel and Composite Structures
• /
• 제28권3호
• /
• pp.267-278
• /
• 2018

Structures may need retrofitting as a result of design and calculation errors, lack of proper implementation, post-construction change in use, damages due to accidental loads, corrosion and changes introduced in new editions of construction codes. Retrofitting helps to compensate weakness and increase the service life. Fiber Reinforced Polymer (FRP) is a modern material for retrofitting steel elements. This study aims to investigate the effect of deficiency location on the axial behavior of compressive elements of Circular Hollow Section (CHS) steel short columns. The deficiencies located vertically or horizontally at the middle or bottom of the element. A total of 43 control column and those with deficiencies were investigated in the ABAQUS software. Only 9 of them tested in the laboratory. The results indicated that the deficiencies had a significant effect on the increase in axial deformation, rupture in deficiency zone (local buckling), and decrease in ductility and bearing capacity. The damages of steel columns were responsible for resistance and stiffness drop at deficiency zone. Horizontal deficiency at the middle and vertical deficiency at the bottom of the steel columns were found to be the most critical. Using Carbon Fiber Reinforced Polymer (CFRP) as the most effective material in retrofitting the damaged columns, significantly helped the increase in resistance and rupture control around the deficiency zone.

• Journal of Trauma and Injury
• /
• 제26권3호
• /
• pp.214-217
• /
• 2013

Tetanus is a neurologic disorder caused by a tetanospasmin released from Clostridium tetani and usually occurs as a result of a dirty open wound or abrasion. Post traumatic tetanus is a life threatening disease and has a mortality rate of 15~39%. Because of a nationwide active immunization program, tetanus is a rare disease in Korea. Thus, many physicians have little experience with its diagnosis and management, and misdiagnosis and therapeutic delay may have catastrophic consequences. We report a case of tetanus that developed in a patient who had been diagnosed with a traumatic rectal rupture.

• 한국분말재료학회지
• /
• 제24권5호
• /
• pp.400-405
• /
• 2017

The addition of a large amount of alloying elements reduces the compactibility and increases the compacting pressure, thereby shortening the life of the compacting die and increasing the process cost of commercial PM steel. In this study, the characteristic changes of Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys are investigated according to the Si contents to replace the expensive elements, such as Ni. All compacts with different Si contents are fabricated with the same green densities of 7.0 and $7.2g/cm^3$. The transverse rupture strength (TRS) and sintered density are measured using the specimens obtained through the sintering process. The sintered density tends to decrease, whereas the TRS increases as the Si content increases. The TRS of the sintered specimen compacted with $7.2g/cm^3$ is twice as high as that compacted with $7.0g/cm^3$.

• 대한기관식도과학회지
• /
• 제5권1호
• /
• pp.14-21
• /
• 1999

Perforating injury of the thoracic esophagus leads to an almost Immediate exposure of the mediastinum to both oral secretions and refluxed gastric contents. And necrotizing inflammatory response developed inevitably. So, without proper managements, mediastinitis results in severe dehydration or septic conditions, and consequently the life of the patient can be threaten. We experienced recently 4 cases of esophageal perforation. Three cases were Boerhaave's syndromes and the other one was instrumental perforation in patient with corrosive esophageal stricture. Curative surgical procedures were done in 3 cases and the drainage procedure was only possible in the other one due to hepatic failure. And the patient with the drainage management was dead.

• Journal of Chest Surgery
• /
• 제40권2호
• /
• pp.140-142
• /
• 2007

제1형 신경섬유종증에서 혈관 병변은 드물지만 매우 치명적일 수 있다. 환자는 제1형 신경섬유종증 가족력이 있는 28세 여자로 갑자기 생긴 배부 통증과 호흡곤란을 주소로 내원하였다. 흉부 전산화단층 촬영상 우측에 다량의 혈흉을 동반한 늑간 동맥류 파열이 발견되었고 생체징후가 불안정하여 응급수술을 시행하였다. 저자들은 자발성 혈흉을 동반한 제1형 신경섬유종증 1예를 치험하였기에 증례보고를 하는 바이다.

• Journal of Chest Surgery
• /
• 제54권3호
• /
• pp.172-178
• /
• 2021

Background: Complicated acute type B aortic dissection is a life-threatening condition with high morbidity and mortality. The aim of this study was to report a single-center experience with endovascular stent-graft repair of acute type B dissection of the thoracic aorta and to evaluate the mid-term outcomes. Methods: We reviewed 18 patients treated for complicated acute type B aortic dissection by thoracic endovascular aortic repair (TEVAR) from September 2011 to July 2017. The indications for surgery included rupture, impending rupture, limb ischemia, visceral malperfusion, and paraplegia. The median follow-up was 34.50 months (range, 12-80 months). Results: The median interval from aortic dissection to TEVAR was 5.50 days (range, 0-32 days). There was no in-hospital mortality. All cases of malperfusion improved except for 1 patient. The morbidities included endoleak in 2 patients (11.1%), stroke in 3 patients (16.7%), pneumonia in 2 patients (11.1%), transient ischemia of the left arm in 1 patient (5.6%), and temporary visceral ischemia in 1 patient (5.6%). Postoperative computed tomography angiography at 1 year showed complete thrombosis of the false lumen in 15 patients (83.3%). Conclusion: TEVAR of complicated type B aortic dissection with a stent-graft was effective, with a low morbidity and mortality rate.

• 대한영상의학회지
• /
• 제83권5호
• /
• pp.1128-1133
• /
• 2022

부갑상선암 수술 중 발생하는 총경동맥 파열은 매우 드물고 생명을 위협하는 질환이다. 저자들은 재발한 부갑상선암을 가진 59세 남자 환자에서 파열된 총경동맥을 응급 피복형 스텐트 삽입을 통해 성공적으로 치료한 증례를 보고한다. 수술 도중 환자의 우측 총경동맥은 갑자기 파열되었고 수술적 대처에도 활력징후가 급속하게 악화되었으나 스텐트 삽입 후 호전되었고 합병증 없이 퇴원하였다.

• Journal of the Korean Wood Science and Technology
• /
• 제43권4호
• /
• pp.456-462
• /
• 2015

KS F 3020-침엽수구조용재 기준에 따라 국산 소나무(Pinus densiflora) $38{\times}140{\times}3600mm$ 구조용 제재목 365개에 대하여 기계등급구분을 실시하고, 휨허용응력을 산출하여 현재 적용되는 KS기준허용응력과 비교 분석하였다. 휨허용응력 계산을 위하여 5% 휨강도 하한값을 75% 신뢰수준의 비모수적 방법, 2-parameter 그리고 3-parameter Weibull 분포를 가정한 모수적 방법, 휨강도-휨탄성계수 직선회귀 방법, 총 4가지 분석방법을 사용하여 결정하였다. 기계등급 E8, E9, E10 만이 비모수적 방법의 통계 처리가 가능한 자료 수를 얻었으며, 휨강도-휨탄성계수 직선회귀 방법은 이론적으로 모든 등급에 대한 5% 하한값 결정이 가능함을 보여주었다. 결정된 등급별 휨허용응력은 기준허용응력에 비하여 모두 낮은 값을 나타내었으며 이것은 과소설계의 위험성이 있는 것으로 현행 기계등급구분체계의 문제점으로 파악되었다. 이러한 문제는 구조설계 신뢰성과 관련하여 반드시 개선되어야 할 것으로, 휨강도-휨탄성계수 조합 등급 도입이 필요할 것으로 생각되었다.

• Journal of the Korean Wood Science and Technology
• /
• 제40권5호
• /
• pp.303-310
• /
• 2012

Heat treatment improves dimensional stability and sound absorption properties of wood. However, mechanical properties of wood can be deteriorated during the heat treatment. The effect of heat treatment on the bending strength and hardness of wood for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at $175^{\circ}C$ and $200^{\circ}C$, respectively. The results showed that the weight and density of wood decreased after heat treatment. It was found that the density by heat treatment was lower at $200^{\circ}C$ than that at $175^{\circ}C$. And, MOE increased with the reduced density. On the contrary, MOR and hardness decreased. In all conditions, It was found that there was a high correlation of 1% level between bending modulus of elasticity and modulus of rupture.

• 동력기계공학회지
• /
• 제19권5호
• /
• pp.45-51
• /
• 2015

Grade 91 steel is used for the major structural components of Generation-IV reactor systems such as a very high temperature reactor (VHTR) and sodium-cooled fast reactor (SFR). Since these structures are designed for up to 60 years at elevated temperatures, the prediction of long-term creep life is very important to determine an allowable design stress of elevated temperature structural component. In this study, a large body of creep rupture data was collected through world-wide literature surveys, and using these data, the long-term creep life was predicted in terms of three methods: Larson-Miller (L-M), Manson-Haferd (M-H) and Wilshire methods. The results for each method was compared using the standard deviation of error. The L-M method was overestimated in the longer time of a low stress. The Wilshire method was superior agreement in the long-term life prediction to the L-M and M-H methods.