Structural Safety Assessment of Cargo Containment System in LNG Carrier under Iceberg Collision

러시아 서부 극지지역에서의 대규모 천연가스(Liquified Natural Gas) 개발과 함께 극지운항 LNG선의 수주가 증가함에 따른 설계 기술력의 확보가 요구되고 있고, 특히 빙산(iceberg)과의 충돌에 대한 LNG선 화물창 단열시스템(CCSAt the time of exploitation of the giant natural gas fields in the Western Arctic regions of Russia, the development of Arctic LNG shipping has been precipitated. There have been demands for the security of design technique of Arctic LNG carrier, especially for the structural safety assessment of the Arctic LNG CCS under the impact of collision with iceberg. To develop iceberg modeling technique and to examine the characteristics of iceberg crushing strength for the more accurate and realistic full scale iceberg-membrane type LNG carrier bow shoulder collision simulations with consideration of surrounding sea water using FSI (Fluid-Structure Interaction) analysis technique, uniaxial compressive ice test specimen simulations in brittle and ductile failure modes were executed and diverse iceberg materials were investigated using LS-DYNA code, such as its failure strain, Young’s modulus, failure stress, failure tensile stress and mesh size. Local zooming analysis of MARK III membrane type LNG CCS according to iceberg sizes and failure strains were performed for the development of its structural safety assessment technique.Fluid-Structure Interaction) 해석기법을 사용하여 주변유체를 고려한 LNG선과의 선수 어깨부위(bow shoulder) 충돌 시뮬레이션을 수행하였다. 또한 취성 및 연성 파손모드에서의 빙(ice) 시험용 시편의 일축압축 시뮬레이션을 수행하였고, 파단변형률(failure strain), 탄성계수 (Young‘s modulus), 파단응력(failure stress), 파단 인장응력(failure tensile stress) 및 유한요소 크기(mesh size) 등과 같은 다양한 빙산의 물성치에 대한 패러미터 연구를 수행하였다. 구조 안전성 평가기법의 개발을 위하여 빙산의 크기와 파단변형률을 고려한 MARK Ⅲ 멤브레인형 LNG CCS의 Local Zooming Analysis의 기법을 개발하여 적용하였다.Cargo Containment System) 구조의 안전성 검증이 매우 중요하다. 보다 정확하고 현실적인 빙산 모델링 기술의 개발과 빙산 분쇄강도(crushing strength)의 특성을 구현하기 위해서 LS-DYNA 코드의 유체-구조 연성(FSI1. Introduction 1 2. Ice Characteristics 5 3. Ice Mechanics and Simulation 8 4. Collision Scenarios and Simulation Models 17 5. Full-Scale Iceberg-Ship Collision Simulation 24 5.1 Response of collision simulation according to failure strain of iceberg 25 5.2 Response of collision simulation according to Young’s modulus of iceberg 27 5.3 Response of collision simulation according to failure stress of iceberg 29 5.4 Response of collision simulation according to failure tensile stress of iceberg 31 5.5 Response of collision simulation according to mesh size of iceberg 33 6. Structural Safety Assessment of CCS 36 7. Conclusions 43 References 4

Cause Investigation on Flooding and Sinking Accident of Pelagic Fishing Vessel using FSI Analysis Technique

원양어선은 베링해에서 황천에서 조업 후 피항하던 중 개구부를 통한 침수로 인하여 침몰하였으며 많은 선원들이 사망하고 실종되었다. 본 연구에서는 유체-구조 연성(Fluid-Structure Interaction, FSI) 해석기법의 고도 정밀 M&S(highly advanced Modeling and Simulation) 시스템을 사용하여 실선 침수⋅침몰 시뮬레이션을 수행하여 침몰사고의 과정 및 원인을 정확하고 과학적으로 분석하고자 하였다. 베링해 침몰사고 시의 기상 및 해상상태를 객관적으로 확보하기 위하여 침몰사고 지역의 시간대별 기상 및 해상 시뮬레이션을 수행하여 침몰사고 당시 파랑과 강풍 등을 분석하고, 불규칙 파랑과 강풍 스펙트럼을 사용하여 구현하였다. 원양어선 사고선박의 선체 도면 등을 통하여 선박의 선형, 배치 및 중량 분포와 외부 해수 침수 개구부 및 선내 침수 경로를 분석하고 주요 탱크들의 용적과 그들의 중량 분포를 추정하여 침수⋅침몰 시뮬레이션을 위한 시나리오를 작성하고, 사고선박 원양어선의 전선과 유체(공기 및 해수)를 상세 모델링을 하였다. 본 연구를 통하여 사고선박의 경우 급격하게 횡경사가 진행되어도 전복에 의한 침몰이 아니라 기관실과 어창에 유입된 다량의 해수로 인하여 무게중심이 다소 아래로 내려가 선미부가 수면 아래로 잠기면서 선미의 침수가 병행한 대각도의 횡경사로 이어진 사고로써, 단순한 복원성 상실로 인한 전복으로 침몰하는 것과는 다른 현상으로 침몰되었다고 수치 시뮬레이션의 거동으로 확인할 수 있었다. | Pelagic fishing vessel was fully flooded through the openings and was sunk down to the bottom of sea due to the very rough sea weather on the way of evasion after fishing operation in the Bearing Sea with many crews dead and/or missed. In this study, full-scale ship flooding & sinking simulation was carried out, and sinking process and cause was analyzed for the precise and scientific investigation of sinking accident using highly advanced M&S(Modeling and Simulation) system of FSI(Fluid-Structure Interaction) analysis technique. For the objective secure of weather and sea states during sinking accident in the Bering Sea, time-based wind and wave simulation at the region of sinking accident was carried out and analyzed, and weather and sea states were realized by simulating the irregular strong wave and wind spectrums. Simulation scenarios were made up and full-scale ship and fluid(air and sea water) modeling was performed for flooding⋅sinking simulation, by investigating the hull form, structural arrangement and weight distribution, the exterior inflow openings and interior flooding paths through its drawings, and by estimating the main tank capacities and their loading status. It could be confirmed that the accident ship was flooding and sunk down from the full-scale ship flooding and sinking simulation behaviors using FSI analysis technique with a little bit different situation from the general capsize and sinking accident due to the simple loss of stability, in that the stern part subsided under the surface with the center of gravity descended a little bit down due to the seawater inflow in the engine room and fish holds, and with continued large angle of heel at the same time of submerged stern part under the surface even though its heel was progressed greatly.목 차 ⅰ List of Tables ⅲ List of Figures ⅳ Abstract ⅷ 초 록 ⅹ 1. 서 론 1 2. 유체-구조 연성 해석기법과 해상상태 분석 및 구현 10 2.1 유체-구조 연성 해석기법 10 2.2 해상상태 분석 및 구현 16 3. 선형 및 구조도 분석과 실선 모델링 23 4. 실선 침수⋅침몰 시뮬레이션 시나리오 및 유체 모델링 32 5. 실선 침수⋅침몰 시뮬레이션 45 5.1 Case 1-0 : 우현 선수각도 44ﾟ로 우현파랑 받으며 항해 49 5.2 Case 1-1 : 피항 개시 후 8ﾟ 우현 경사 55 5.3 Case 1-2 : 좌현횡파에 의한 20ﾟ 우현 경사 62 5.4 Case 1-3 : 좌현횡파에 의한 25∼30ﾟ 우현 경사 73 5.5 Case 1-4 : 좌현횡파에 의한 35ﾟ 우현 경사 82 5.6 Case 2-0 : 어획물 좌현 이동 시 좌현횡파에 일시 평형 88 5.7 Case 2-1 : 우현횡파에서 좌현 측 5ﾟ~10ﾟ 경사 99 5.8 Case 2-2 : 우현횡파에서 좌현 측 30ﾟ∼35ﾟ 경사 105 5.9 Case 2-3 : 우현횡파에서 좌현 측 45ﾟ∼55ﾟ 경사 115 5.10 Case 2-4 : 우현횡파에서 좌현 측 60ﾟ∼70ﾟ 경사 125 5.11 Case 2-5 : 우현횡파에서 좌현 측 80ﾟ 이상 경사 131 5.12 고찰 135 6. 결론 136 References 138 감사의 글 141Docto

Frequency-Doubled Double-Pulse Nd:YAG (FREDDY) Laser for the Treatment of Ureteral Stone: Initial Experience

Purpose: We assessed the effectiveness, safety and accessibility of performing FREDDY laser lithotripsy for managing urinary tract calculi. Materials and Methods: From January 1999 to May 2005, 173 consecutive patients underwent endoscopic lithotripsy with FREDDY laser lithotripsy. The numbers of patients, according to stone location, were 18 patients for the upper ureter, 11 for the mid ureter and 144 for the lower ureter. Patients were treated with a rigid endoscope on a day surgery basis. Patients were assessed 6 to 12 weeks postoperatively with KUB and ultrasound or excretory urography for determining the late obstructive complications. Results: The mean stone size and mean operation time were 7.8mm and 36.6 minutes, respectively. The overall stone-free rates were 98.9%. The stone-free rates according to stone location were 100% in the upper ureter, 100% in the mid ureter and 98.6% in the lower ureter. There were no post-operative complications. Interestingly, there were no significant differences in the operation times and stone-free rates between the urologic specialists (36.7 min and 100%, respectively) and the training residents (37.1 min and 98.6%, respectively). Conclusions: FREDDY laser lithotripsy is a highly effective and safe modality for the treatment of ureteral stone. In addition, FREDDY laser lithotripsy is very feasible for training residents.ope

ABCD2 Is a Direct Target of β-Catenin and TCF-4: Implications for X-Linked Adrenoleukodystrophy Therapy

X-linked adrenoleukodystrophy (X-ALD) is a peroxisomal disorder caused by mutations in the ABCD1 gene that encodes the peroxisomal ATP-binding cassette (ABC) transporter subfamily D member 1 protein (ABCD1), which is referred to as the adrenoleukodystrophy protein (ALDP). Induction of the ABCD2 gene, the closest homolog of ABCD1, has been mentioned as a possible therapeutic option for the defective ABCD1 protein in X-ALD. However, little is known about the transcriptional regulation of ABCD2 gene expression. Here, through in silico analysis, we found two putative TCF-4 binding elements between nucleotide positions −360 and −260 of the promoter region of the ABCD2 gene. The transcriptional activity of the ABCD2 promoter was strongly increased by ectopic expression of β-catenin and TCF-4. In addition, mutation of either or both TCF-4 binding elements by site-directed mutagenesis decreased promoter activity. This was further validated by the finding that β-catenin and the promoter of the ABCD2 gene were pulled down with a β-catenin antibody in a chromatin immunoprecipitation assay. Moreover, real-time PCR analysis revealed that β-catenin and TCF-4 increased mRNA levels of ABCD2 in both a hepatocellular carcinoma cell line and primary fibroblasts from an X-ALD patient. Interestingly, we found that the levels of very long chain fatty acids were decreased by ectopic expression of ABCD2-GFP as well as β-catenin and TCF-4. Taken together, our results demonstrate for the first time the direct regulation of ABCD2 by β-catenin and TCF-4.ope

Comparison of Melanoma Subtypes among Korean Patients by Morphologic Features and Ultraviolet Exposure

BACKGROUND: Genetic alterations have been identified in melanomas according to different levels of sun exposure. Whereas the conventional morphology-based classification provides a clue for tumor growth and prognosis, the new classification by genetic alterations offers a basis for targeted therapy. OBJECTIVE: The purpose of this study is to demonstrate the biological behavior of melanoma subtypes and compare the two classifications in the Korean population. METHODS: A retrospective chart review was performed on patients found to have malignant melanoma in Severance Hospital from 2005 to 2012. Age, sex, location of the tumor, histologic subtype, tumor depth, ulceration, lymph node invasion, visceral organ metastasis, and overall survival were evaluated. RESULTS: Of the 206 cases, the most common type was acral melanoma (n=94, 45.6%), followed by nonchronic sun damage-induced melanoma (n=43, 20.9%), and mucosal melanoma (n=40, 19.4%). Twenty-one patients (10.2%) had the chronic sun-damaged type, whereas eight patients (3.9%) had tumors of unknown primary origin. Lentigo maligna melanoma was newly classified as the chronic sun-damaged type, and acral lentiginous melanoma as the acral type. More than half of the superficial spreading melanomas were newly grouped as nonchronic sun-damaged melanomas, whereas nodular melanoma was rather evenly distributed. CONCLUSION: The distribution of melanomas was largely similar in both the morphology-based and sun exposure-based classifications, and in both classifications, mucosal melanoma had the worst 5-year survival owing to its tumor thickness and advanced stage at the time of diagnosis.ope

서 론 최근 10년간, 한국에서 위 내시경 등의 검사가 증가하면서 조기 위 암이 점점 증가하고 있다. 전체 위암 중 조기 위암의 비율이 최대 50%까지도 보고되고 있다[1]. 이에 영향을 받아 내시경적 점막하절 제술, 내시경적 점막절제술 등의 내시경적 절제술이 증가하는 추세 이다[2]. 조기 위암에 대한 내시경적 절제술은 최소침습적이며 의료 비용을 낮추는 효과도 있다[3]. 그러나, 내시경적 절제술이 늘어나면서 적응증도 확대기준을 적 용하는 사례가 많아

Purpose: The increase in the incidence of early gastric cancer (EGC) cases has led to an increase in endoscopic resections, thereby resulting in an increasing number of endoscopic resection failure cases. The purpose of this study was to identify indicators for endoscopic resection, such as depth of invasion and tumor differentiation. Methods: This study included 273 patients who underwent endoscopic resection for EGC at Hallym University Sacred Heart Hospital from January 2006 to May 2013. Of these resection cases, 41 were also surgical treatment cases. The endoscopic findings and lesion characteristics were analyzed, retrospectively using medical records. Results: The results suggested that when the location of tumor was in the middle third of the stomach (P= 0.002), the patient was younger (P= 0.057), there was a higher likelihood of surgical treatment after endoscopic resection. Conclusion: To determine the indicators for endoscopic resection, it is essential to consider tumor location as well as tumor size, tumor differentiation and depth of invasion, which are considered important factors. If the lesion was located in the upper and middle third of the stomach, sufficient explanation and consent was required

남아프리카 공화국 핀치 지역에서 발견되는 석류석 감람암의 변형 미구조

학위논문 (석사)-- 서울대학교 대학원 : 지구환경과학부, 2011.8. 정해명.Maste

압축기 슈라우드 캐비티에 기인한 손실의 실험적 연구

Thesis(master`s)--서울대학교 대학원 :기계항공공학부,2005.Maste

Generation of regionally specified oligodendrocyte precursor cells from human pluripotent stem cells

의과학과/석사현재 몇몇 논문에서 인간 전분화능 줄기세포를 이용하여 척수 내의 희돌기교세포로의 분화 방법이 보고 되었으나 그 기간이 길고, 제현성이 떨어진다. 이에 분화기간을 줄이고, 제현성이 높은 분화 방법을 찾고자 하였다. 신경관을 이루고 있는 신경상피세포는 특정 신호에 의해서 중추 신경관을 이루고 있는 다양한 신경세포로의 분화가 가능하다. 신경관이 발생할 때, 천장판에서는 Bone morphogenic protein (BMP) 신호가 발생하고, 바닥판에서는 Sonic hedgehog (SHH) 신호가 발생하여 등-배 축을 형성한다. 또한 신경관이 척수로 발생 할 때, 원 체절에서 발생하는 Retinoic acid (RA)와 헨센 마디에서 발생하는 basic Fibroblast growth factor (bFGF) 신호의 영향을 받아 앞-뒤 축을 형성하게 된다. 척수 내 희돌기교세포 전구체는 앞에서 언급한 신호들을 받아 척수의 배 축에 존재하는 Motor neuron progenitor domain (pMN)이라는 특정 부분에서 주로 발생하며 전사인자인 Olig2를 특이적으로 발현한다. 이에 인간 전분화능 줄기세포를 이용하여 pMN부위의 희돌기교세포 전구체로 분화시키기 위해 Dosomorphin (DM)를 이용하여 BMP 신호를 억제하고 SHH 신호를 주어 배 축으로 분화를 유도하였고, RA와 bFGF 신호를 주어 뒤 축으로 분화를 유도하였다. SHH 신호에 의해 전사인자인 Nkx2.2가 발현 함으로써 배 축으로의 분화를 확인하였고, RA, bFGF 신호에 의해 Hox 유전자가 발현 함으로써 척수쪽으로 분화가 된 것을 확인하였다. 그리고 이 모든 신호에 의해 pMN부분에서만 특이적으로 발현하는 Olig2가 발현하는 것을 확인 하였다. Olig2의 발현으로 희돌기교세포 전구체로의 분화 가능성 또한 확인하게 되었다.ope

Histomorphological factors in the risk prediction of lymph node metastasis in papillary thyroid carcinoma

AIMS: Few clinicopathological parameters have been identified as independent predictive factors for lymph node metastasis. This study evaluated the predictive ability of three histological characteristics of PTC in lymph node metastases: hobnail features, loss of cohesiveness/polarity (LOCP) and micropapillary structures. METHODS AND RESULTS: Tissue specimens from 153 patients with histologically confirmed PTC including 112 cases of papillary thyroid microcarcinoma (PTMC) were enrolled in this study. Three histological characteristics (hobnail features, LOCP and micropapillary structures) and several clinicopathological parameters were evaluated for their value in predicting lymph node metastasis. Hobnail features, LOCP and micropapillary structures were each significantly associated with and found to be independent predictive factors for lymph node metastasis (P < 0.05). These three histological characteristics were closely correlated with one another (P < 0.001). Six of the seven possible combinations of these three histological characteristics were independently correlated with lymph node metastasis (P < 0.05). Among these combinations, the coincidence of all three histological parameters represented the strongest independent predictive factor for lymph node metastasis (OR: 3.270, P = 0.006). CONCLUSIONS: Our study demonstrates that hobnail features, LOCP and micropapillary structures, either alone or in combinations, represent strong independent predictive factors for lymph node metastasis in PTC.ope