• Title/Summary/Keyword: failure causes

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Study on the estimation of uncertainty for the air-borne noise measurements in a naval ship (함정 내 소음 평가를 위한 불확도 추정 기법 연구)

  • Kim, Seong-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.38 no.4
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    • pp.396-402
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    • 2014
  • The measurement of air-borne noise in a naval ship is a crucial element. Because the noise in a naval ship interferes with a communication between crews and finally it causes to reduce the combat power. Thus, most of newly built ships have to satisfy the criteria of air-borne noise in the stage of delivery of a naval ship. In order to evaluate success or failure of criteria, uncertainty of the measurement should be considered. This study introduces the test method for the measurement of the air-borne noise in a naval ship and is concerned with the evaluation of uncertainty. The uncertainty results which was from the measurement of air-borne noise in 7 naval ships newly built satisfy the error tolerance(2dB). Therefore, it is need to reduce the error tolerance for the reliable measurement result.

The Literary study on Chongmai (충맥(衝脈)에 대(對)한 문헌적(文獻的) 고찰(考察))

  • Kim, Seong-Il;Song, Choon-Ho
    • Journal of Acupuncture Research
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    • v.17 no.2
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    • pp.85-93
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    • 2000
  • We came to the conclusion after considering all the information from many kinds of books on the circulation courses, cross-link points, functions and the symptoms of disease of Chongmai. The results were as follows : 1. The Chongmai that starts from a Uterus flows to Dazhu through the inside of vertebra after joining Renmai and Duimai at Huiyin. The Chongmais up-line that comes out from Qichong into a surface of body arrives and is scattered at a chest through an abdomen. One strand of them goes upward again and is connected to a throat and lips area. After coming out from Qichong, separated down-line is divided into two parts when it arrives a inner part of a heel through the inner part of a leg. One is for an instep, the other is for the sole of a foot. 2. We call it "Sea of Twelve Meridians" or "Meridian's Sea". Because Chongmai controls all of Meridian by acquired "Basic energy" as getting Stomach's energy, Kidney's energy and air-energy, and there are responsible of physiological phenomenon control. And also we name it "Sea of Blood", because it starts from and provides a nutrition to Uterus. 3. All of these four Meridian such as Renmai, Kidney Meridian, Stomach Meridian and Spleen Meridian are ones that flow around the part of a chest and an abdomen. Chongmai makes energy and blood circulation of a chest and an abdomen be stronger and be controlled. Therefore it makes viscera, bowels and body surface be warm and given a nutrition. So Chongmai becomes "Sea of Viscera and Bowels". 4. Chongmai provides a nutrition for ligament and muscle and makes legs get warm as making energy and blood circulate from head to foot. If Chongmai is energetic, hair is completely easy to grow. 5. To see in pathological phase, Chongmais failure or weakness causes like a chest pain, stomachache, heart attack, a menstrual irregularity and sterility and so on. And also if Chongmai is damaged, it happens that giving a nutrition for lips area is stopped, and then mustache doesn't grow any more.

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Parallel Computing Strategies for High-Speed Impact into Ceramic/Metal Plates (세라믹/금속판재의 고속충돌 파괴 유한요소 병렬 해석기법)

  • Moon, Ji-Joong;Kim, Seung-Jo;Lee, Min-Hyung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.6
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    • pp.527-532
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    • 2009
  • In this paper simulations for the impact into ceramics and/or metal materials have been discussed. To model discrete nature for fracture and damage of brittle materials, we implemented cohesive-law fracture model with a node separation algorithm for the tensile failure and Mohr-Coulomb model for the compressive loading. The drawback of this scheme is that it requires a heavy computational time. This is because new nodes are generated continuously whenever a new crack surface is created. In order to reduce the amount of calculation, parallelization with MPI library has been implemented. For the high-speed impact problems, the mesh configuration and contact calculation changes continuously as time step advances and it causes unbalance of computational load of each processor. Dynamic load balancing technique which re-allocates the loading dynamically is used to achieve good parallel performance. Some impact problems have been simulated and the parallel performance and accuracy of the solutions are discussed.

Effect of corrosion on the ultimate strength of double hull oil tankers - Part II: hull girders

  • Kim, Do Kyun;Park, Dae Kyeom;Park, Dong Hee;Kim, Han Byul;Kim, Bong Ju;Seo, Jung Kwan;Paik, Jeom Kee
    • Structural Engineering and Mechanics
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    • v.42 no.4
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    • pp.531-549
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    • 2012
  • Numerous oil tanker losses have been reported and one of the possible causes of such casualties is caused by the structural failure of aging ship hulls in rough weather. In aging ships, corrosion and fatigue cracks are the two most important factors affecting structural safety and integrity. This research is about effect on hull girder ultimate strength behavior of double hull oil tanker according to corrosion after Part I: stiffened panel. Based on corrosion data of Part I (time-dependent corrosion wastage model and CSR corrosion model), when progressing corrosion of fourtypes of double hull oil tankers (VLCC, Suezmax, Aframax, and Panamax), the ultimate strength behavior of hull girder is compared and analyzed. In case of the ultimate strength behavior of hull girder, when occurring corrosion, the result under vertical and horizontal bending moment is analyzed. The effect of time-dependent corrosion wastage on the ultimate hull girder strength as well as the area, section modulus, and moment of inertia are also studied. The result of this research will be useful data to evaluate ultimate hull girder strength of corroded double hull oil tanker.

A Study on the Optimal Replacement Periods of Digital Control Computer's Components of Wolsung Nuclear Power Plant Unit 1 (월성 원자력 발전소 1호기의 디지탈 제어컴퓨터 부품들의 최적교체주기에 관한연구)

  • Mok, Jin-Il;Seong, Poong-Hyun
    • Nuclear Engineering and Technology
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    • v.25 no.3
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    • pp.430-436
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    • 1993
  • Due to the failure of the instrument and control devices of nuclear power plants caused by aging, nuclear power plants occasionally trip. Even a trip of a single nuclear power plant (NPP) causes an extravagant economical loss and deteriorates public acceptance of nuclear power plants. Therefore, the replacement of the instrument and control devices with proper consideration of the aging effect is necessary in order to prevent the inadvertent trip. In this paper we investigated the optimal replacement periods of the control computer's components of Wolsung nuclear power plant Unit 1. We first derived mathematical models for optimal replacement periods to the digital control computer's components of Wolsung NPP Unit 1 and calculated the optimal replacement periods analytically. We compared the periods with the replacement periods currently used at Wolsung NPP Unit 1. The periods used at Wolsung is not based on mathematical analysis, but on empirical knowledge. As a consequence, the optimal replacement periods analytically obtained and those used in the field show a little difference.

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Results of Tracheal Resection with End-to-end Anastomosis (기관절제술후 기관 단단문합술 치험 결과)

  • Shin Dong-Jin;Cho Woo-Jin;Baek Sungkuk;Woo Jeong Su;Kwon Soon-Young;Jung Kwang-Yoon
    • Korean Journal of Bronchoesophagology
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    • v.10 no.1 s.19
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    • pp.41-45
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    • 2004
  • Tracheostomy and endotracheal intubation are often performed in patients with acute and chronic respiratory failure. Recently, the incidence of iatrogenic tracheal stenosis has increased. Tracheal resection and end-to-end anastomosis would be one of the most physiologic treatment options for severe tracheal stenosis. Also, this treatment can be applied to the management of trachea invaded by thyroid cancer and tracheal neoplasm. The authors aimed to analyze the outcomes of end-to-end anastomosis of trachea following segmental resection in tracheal stenosis and tracheal invasion of cancer that we have recently experienced. Materials and methods Authors retrospectively studied 19 cases treated by tracheal resection with end-to-end anastomosis between Feburuary 1996 and January 2003. 12 patients had tracheal stenosis, 6 patients had tracheal invasion by thryroid cancer and 1 patient had tracheal cancer. We analyzed the direct causes of tracheal stenosis, preoperative vocal cord function, operation technique, early and delayed postoperative complications, and the outcome of end-to-end anastomois. Result Decannulation without significant aspiration was achieved in 16 cases($89.5\%$). A 27 year-old man could not be decannulated because of restenosis. A 62 year-old woman could not be decannulated because of bilateral vocal cord palsy. Conclusion End-to-end anastomosis is a safe and effective surgical method for tracheal stenosis. Case selection for end-to-end anastomosis and preservation of recurrent laryngeal nerve during operation is very important.

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Study of Structural Stability for H-section Beams Made of Fire Resistant Steels (FR 490) at High Temperatures by Analytical Method (건축용 내화강재(FR 490) 적용 H형강 보부재의 고온내력 연구)

  • Kwon, In-Kyu
    • Fire Science and Engineering
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    • v.28 no.5
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    • pp.52-57
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    • 2014
  • When structural elements of steel framed structures are exposed to fire situations, the structural stability begins to decrease due to dislocation of substantial. The increase of the beam length causes an additional stress and deflection. These can be serious factors to cause a severe failure of structures. To improve the fire resistance of beams, prevention of the heat from a fire by coating with fire protection material is essential for beams. The FR 490 was developed to enhance fire resistance compared with SM 490 steel. However, the fire resistance of FR 490 H-beams has not been evaluated by analysis method since it was developed. In this paper, materials properties in high temperature and a heat transfer and thermal stress theory were used in the evaluation of the fire resistance of FR490 H-beams. The fire resistance of FR490 steel beams was compared with that of SM490 beams. The comparison verified that the structural stability of FR490 beams at high temperature was superior to that of SM490 beams.

Flagellin-Stimulated Production of Interferon-β Promotes Anti-Flagellin IgG2c and IgA Responses

  • Kang, Wondae;Park, Areum;Huh, Ji-Won;You, Gihoon;Jung, Da-Jung;Song, Manki;Lee, Heung Kyu;Kim, You-Me
    • Molecules and Cells
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    • v.43 no.3
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    • pp.251-263
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    • 2020
  • Flagellin, a major structural protein of the flagellum found in all motile bacteria, activates the TLR5- or NLRC4 inflammasome-dependent signaling pathway to induce innate immune responses. Flagellin can also serve as a specific antigen for the adaptive immune system and stimulate anti-flagellin antibody responses. Failure to recognize commensal-derived flagellin in TLR5-deficient mice leads to the reduction in anti-flagellin IgA antibodies at steady state and causes microbial dysbiosis and mucosal barrier breach by flagellated bacteria to promote chronic intestinal inflammation. Despite the important role of anti-flagellin antibodies in maintaining the intestinal homeostasis, regulatory mechanisms underlying the flagellin-specific antibody responses are not well understood. In this study, we show that flagellin induces interferon-β (IFN-β) production and subsequently activates type I IFN receptor signaling in a TLR5- and MyD88-dependent manner in vitro and in vivo. Internalization of TLR5 from the plasma membrane to the acidic environment of endolysosomes was required for the production of IFN-β, but not for other pro-inflammatory cytokines. In addition, we found that anti-flagellin IgG2c and IgA responses were severely impaired in interferon-alpha receptor 1 (IFNAR1)-deficient mice, suggesting that IFN-β produced by the flagellin stimulation regulates anti-flagellin antibody class switching. Our findings shed a new light on the regulation of flagellin-mediated immune activation and may help find new strategies to promote the intestinal health and develop mucosal vaccines.

Claim Management during Construction based on Key Claim Management Factors (클레임 핵심관리요인을 기반으로 한 건설공사 중의 클레임 관리)

  • Lee, Jun-Hyung;Lee, Hyun-Soo;Park, Moon-Seo;Kim, In-Ho
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.463-468
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    • 2007
  • The disputes in construction projects are very important issue for stakeholders. However, many of presented claims have not received the compensation money required, and frequently turned down. The most cause is that the claims are not managed systemically on construction. Therefore, it is important to identify which management works are conducted on construction and how significantly do they relevant to construction claim. This research derives key claim management factors through analyzing causes for claim success and failure, and then presents management works relevant to them. This research also proposes the method for effective claim management and its expected effect through expert interview.

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Analysis of Cause of Excavator Safety Accidents according to the Accident Case Study (중대재해사례를 통한 굴삭기 안전사고 원인분석)

  • Seo, Jong-Min;Han, Kap-Kyu;Lim, Ji-Young;Kim, Sun-Kuk
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.450-454
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    • 2007
  • In line with the construction projects, which have been increasingly getting larger and complex, safety accident has been on the rise, particularly those in association with the construction equipment. In a bid to prevent the safety accident, it's needed to analyze the cause of such accidents. The thesis was intended to identify the cause of safety accident by reviewing the cases of construction disaster complied by Korea Occupational Safety and Health Agency. The cases subject to study were limited to the accident by excavator. Summarizing the study is as follows. 1) Among the cause of accidents caused by excavator were, in order of high frequency, being caught in equipment or machine, falling, being crashed or bumped. 2) Among the causes of accident were, in order of high frequency, worker's unauthorized presence within the range of equipment operation. inappropriate use, failure of equipment inspection prior to starting work and inappropriate work method. The study is highly expected to pave the foundation for further study as well as to make commitment to mitigating the safety accident.

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