• Title/Summary/Keyword: impact failure

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The expected impact regional development factors, according to the World Bamboo Expo held on regional and aechakdo be held and held persistence (세계 대나무박람회 개최에 따른 지역발전영향요인이 지역애착도와 개최지지 및 개최속성에 미치는 영향연구)

  • An, Tai-Gi
    • Journal of the Korea Convergence Society
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    • v.8 no.1
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    • pp.131-138
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    • 2017
  • The purpose of research and bamboo for failure, Damyang-county, Jeollanam-do at 2015 Damyang bamboo the world fairs held according to the attachment to local factors impact of regional development and hosting support. To identify the impact on the property held. Fair after setting up a hypothesis to carry out research in the visitors through after sample surveys and survey and Empirical Analysis. Show areas are improving in the future, due to host tourists want to come up with the purpose of research to become a popular tourist attraction again. Attachment or environmental factors and social factors showed that, and affect the region. The host of social factors turned out to be the biggest influence, and economic factors, environmental factors shown to affect, and to a venue in order.Attachment is a factor appears to be affecting the region was the venue. The property is shown to environmental factors is not statistically significant, and host local affection, support appears to be factors affecting the holding. As a result, Fair, held regional attachment to the Influence Factors of regional development support, and according to the next fair in the Region and through the impact on the property held.Evaluation strategy could contribute to explore the festival.

A Numerical Study on the Response of the Tibial Component in Total Knee Arthroplasty to Longitudinal Impact (인공무릎관절 전치환술에 있어 축방향 충격에 의한 Tibial Component의 응답 특성 분석 연구)

  • 조용균;조철형;최재봉;이태수;최귀원
    • Journal of Biomedical Engineering Research
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    • v.19 no.5
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    • pp.503-511
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    • 1998
  • In this study, the stress distribution for different tibial components was observed In order to Investigate the load transfer and potential failure mechanism of the tibial components subjected to dynamic impact loading and also to evacuate the effect of bone-implant bonding conditions on the implant system. The 3-dimensional finite element models included an intact tibia, cemented metal-backed tibial component, uncemented metal-blocked tibial component, cemented all-polyethylene tibial component, and metal-backed component with a debonded bone/stem interface. The results showed that the cemented metal-hocked component Induced slightly higher peak stress at stem tip than the uncemented component. The peak stress of the all-polyethylene tibia1 component at stem trip showed about half thats of metal-backed tibial components. The all-polyethylene component showed a similar dynamic response to intact tibia. In case of debonded bone/stem interface, the peak stress below the metal tray was three times Higher than that of the fully bonded interface and unstable stress distribution at the stem tip was observed with time, which causes another adverse bone apposition and implant loosening. Thus, the all-polyethylene tibial component bonded fully to the surrounding bone might be most desirable system under an impact loading.

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Comparative study on dynamic properties of argillaceous siltstone and its grouting-reinforced body

  • Huang, Ming;Xu, Chao-Shui;Zhan, Jin-Wu;Wang, Jun-Bao
    • Geomechanics and Engineering
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    • v.13 no.2
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    • pp.333-352
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    • 2017
  • A comparison study is made between the dynamic properties of an argillaceous siltstone and its grouting-reinforced body. The purpose is to investigate how grout injection can help repair broken soft rocks. A slightly weathered argillaceous siltstone is selected, and part of the siltstone is mechanically crushed and cemented with Portland cement to simulate the grouting-reinforced body. Core specimens with the size of $50mm{\times}38mm$ are prepared from the original rock and the grouting-reinforced body. Impact tests on these samples are then carried out using a Split Hopkinson Pressure Bar (SHPB) apparatus. Failure patterns are analyzed and geotechnical parameters of the specimens are estimated. Based on the experimental results, for the grouting-reinforced body, its shock resistance is poorer than that of the original rock, and most cracks happen in the cementation boundaries between the cement mortar and the original rock particles. It was observed that the grouting-reinforced body ends up with more fragmented residues, most of them have larger fractal dimensions, and its dynamic strength is generally lower. The mass ratio of broken rocks to cement has a significant effect on its dynamic properties and there is an optimal ratio that the maximum dynamic peak strength can be achieved. The dynamic strain-softening behavior of the grouting-reinforced body is more significant compared with that of the original rock. Both the time dependent damage model and the modified overstress damage model are equally applicable to the original rock, but the former performs much better compared with the latter for the grouting-reinforced body. In addition, it was also shown that water content and impact velocity both have significant effect on dynamic properties of the original rock and its grouting-reinforced body. Higher water content leads to more small broken rock pieces, larger fractal dimensions, lower dynamic peak strength and smaller elastic modulus. However, the water content plays a minor role in fractal dimensions when the impact velocity is beyond a certain value. Higher impact loading rate leads to higher degree of fragmentation and larger fractal dimensions both in argillaceous siltstone and its grouting-reinforced body. These results provide a sound basis for the quantitative evaluation on how cement grouting can contribute to the repair of broken soft rocks.

Conservation Treatment of Sand Stone by Pressurized Impregnation with Acrylic Materials (아크릴계 보존처리제를 이용한 사암의 가압함침 보존처리)

  • Kim, Youn-Cheol;Kim, Sa-Duk;Kim, Hyung-Joong
    • Journal of Conservation Science
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    • v.27 no.4
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    • pp.395-401
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    • 2011
  • After pressurized impregnation treatment, which has been proposed as an effective conservation method for stone cultural property, was executed with methyl metacrylate (MMA), MMA-butyl acrylate (PMB73) mixture and MMA-vinyl trimethoxy silane (PMV5) co-monomer mixture, the physical-chemical properties on the sand stone and the granite impregnated were evaluated. Compared to the case of granite, the impregnation ratios of sand stone showed larger values in the range of 3.2 to 3.7 wt% and these were increased up to 32% when the decompression process was applied to autoclave. The physical properties of sand stone such as anti-moisture property, flexural strength, impact property and ultrasonic velocity were also higher values than those of granite, which can be interpreted by high impregnation ratio resulted in many void within sand stone. The impact failure energy was 1.22 J for PMMA, 1.84 J for PMB73, and 2.8 J for PMV5, respectively. Since the inorganic affinity of treatment agent is more effective than the molecular structure of acrylic agent, PMV5 improved inorganic property indicates the optimum impact property.

Impact of antimicrobial resistance in the $21^{st}$ century

  • Song, Jae-Hoon
    • Proceedings of the Korean Society for Applied Microbiology Conference
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    • 2000.04a
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    • pp.3-6
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    • 2000
  • Antimicrobial resistance has been a well-recognized problem ever since the introduction of penicillin into clinical use. History of antimicrobial development can be categorized based on the major antibiotics that had been developed against emerging resistant $pathogens^1$. In the first period from 1940 to 1960, penicillin was a dominating antibiotic called as a "magic bullet", although S.aureus armed with penicillinase led antimicrobial era to the second period in 1960s and 1970s. The second stage was characterized by broad-spectrum penicillins and early generation cephalosporins. During this period, nosocomial infections due to gram-negative bacilli became more prevalent, while those caused by S.aureus declined. A variety of new antimicrobial agents with distinct mechanism of action including new generation cephalosporins, monobactams, carbapenems, ${\beta}$-lactamase inhibitors, and quinolones characterized the third period from 1980s to 1990s. However, extensive use of wide variety of antibiotics in the community and hospitals has fueled the crisis in emerging antimicrobial resistance. Newly appeared drug-resistant Streptococcus pneumoniae (DRSP), vancomycin-resistant enterococci (VRE), extended-spectrum ${\beta}$-lactamase-producing Klebsiella, and VRSA have posed a serious threat in many parts of the world. Given the recent epidemiology of antimicrobial resistance and its clinical impact, there is no greater challenge related to emerging infections than the emergence of antibiotic resistance. Problems of antimicrobial resistance can be amplified by the fact that resistant clones or genes can spread within or between the species as well as to geographically distant areas which leads to a global concern$^2$. Antimicrobial resistance is primarily generated and promoted by increased use of antimicrobial agents. Unfortunately, as many as 50 % of prescriptions for antibiotics are reported to be inappropriate$^3$. Injudicious use of antibiotics even for viral upper respiratory infections is a universal phenomenon in every part of the world. The use of large quantities of antibiotics in the animal health industry and farming is another major factor contributing to selection of antibiotic resistance. In addition to these background factors, the tremendous increase in the immunocompromised hosts, popular use of invasive medical interventions, and increase in travel and mixing of human populations are contributing to the resurgence and spread of antimicrobial resistance$^4$. Antimicrobial resistance has critical impact on modem medicine both in clinical and economic aspect. Patients with previously treatable infections may have fatal outcome due to therapeutic failure that is unusual event no more. The potential economic impact of antimicrobial resistance is actually uncountable. With the increase in the problems of resistant organisms in the 21st century, however, additional health care costs for this problem must be enormously increasing.

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Rheological and Failure Properties of Polycarbonate/Poly(butylene terephthalate) Blends (폴리카보네이트/폴리(부틸렌 테레프탈레이트) 블렌드의 유변학적 및 파괴특성)

  • Nah, Chang-Woon;Huh, Mong-Young;Choi, Dae-Hwan;Kook, Jeong-Ho;Hwang, In-Ra;Jeong, Kwang-Un;Hong, Chang-Kook
    • Polymer(Korea)
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    • v.31 no.5
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    • pp.399-403
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    • 2007
  • Trans-esterification behavior of polycarbonate/poly(butylene terephthalate) (PC/PBT) blends was investigated during the melt mixing process. Rheological and fracture behaviors, and fracture morphology were also investigated as a function of PC/PBT blend ratio. Based on FT-IR and $^1H-NMR$ results, a trans-esterification reaction was confirmed to occur between PC and PBT during the melt mixing process. The melt index(MI) decreased with increased PC content, indicating the higher flow resistance of PC. The storage and loss moduli were increased by increasing the PC loading, and the PC/PBT blends were rheologically incompatible based on the Cole-Cole plot. The tensile property increased linearly with the increased PC content. However, the impact strength increased until 50 wt% of PC loading, notably around $30{\sim}40wt%$, and then was levelled off at 50 wt%. Rough ridges were formed on the impact fracture surfaces above the 40 wt% of PC content, supporting the observed higher impact strength in this range.

Numerical Simulation based on SPH of Bullet Impact for Fuel Cell Group of Rotorcraft (입자법 기반 항공기용 연료셀 그룹 피탄 수치모사)

  • Kim, Hyun Gi;Kim, Sung Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.2
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    • pp.71-78
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    • 2014
  • There is a big risk of bullet impact because military rotorcraft is run in the battle environment. Due to the bullet impact, the rapid increase of the internal pressure can cause the internal explosion or fire of fuel cell. It can be a deadly damage on the survivability of crews. Then, fuel cell of military rotorcraft should be designed taking into account the extreme situation. As the design factor of fuel cell, the internal fluid pressure, structural stress and bullet kinetic energy can be considered. The verification test by real object is the best way to obtain these design data. But, it is a big burden due to huge cost and long-term preparation efforts and the failure of verification test can result in serious delay of a entire development plan. Thus, at the early design stage, the various numerical simulations test is needed to reduce the risk of trial-and-error together with prediction of the design data. In the present study, the bullet impact numerical simulation based on SPH(smoothed particle hydrodynamic) is conducted with the commercial package, LS-DYNA. Then, the resulting equivalent stress, internal pressure and bullet's kinetic energy are evaluated in detail to examine the possibility to obtain the configuration design data of the fuel cell.

The Industrial Economic Costs of Unsupplied Electricity in OECD Countries using Input-Output Analysis (산업연관분석을 활용한 전력의 산업별 공급지장비용 평가 : OECD 국가를 중심으로)

  • Lee, Seung-Jae;Jeong, Dong-Won;Yu, Jae-Gab
    • Journal of the Korea Convergence Society
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    • v.7 no.4
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    • pp.191-198
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    • 2016
  • As the electricity produced from the electricity industry, a national key industry in Korea, are supplied to other industries as an intermediate goods, the supply shortage of electricity industry has a large impact on the national economy. This paper attempts to analyze the supply shortage effects which are defined as the negative impact of one won of supply failure in the electricity on the production of other industries. To this end, an input-output analysis using an input-output (I-O) table describing inter-industry flow of intermediate goods is applied. More concretely, the supply-driven model is applied subject to the OECD countries. The value of the supply effects interfere with Denmark's best large 1.682 was followed by South Korea, Japan, Australia, the UK.

Impact of radiation dose on concurrent chemoradiotherapy for limited-stage small-cell lung cancer

  • Park, Junhee;Kang, Min Kyu
    • Radiation Oncology Journal
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    • v.36 no.1
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    • pp.35-44
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    • 2018
  • Purpose: To evaluate clinical outcomes according to radiation dose in patients with limited-stage small-cell lung cancer (LS-SCLC) treated with concurrent chemoradiotherapy (CCRT). Materials and Methods: From January 2006 to December 2015, 38 patients with LS-SCLC were treated with CCRT with etoposide and cisplatin. Total radiation doses ranged from 45 Gy to 66 Gy (1.8-2 Gy/fraction) and were classified into three groups: 45-54 Gy, 60-63 Gy, and 66 Gy. The impact of radiation dose on survival outcomes were evaluated. Toxicities were evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. Results: The median follow-up period was 21 months. The 2-year overall survival (OS) and local failure-free survival (LFFS) rates were 45.8% and 67.5%, respectively. The 2-year LFFS rates were 33.3% for 45-54 Gy group, 68.6% for 60-63 Gy group, and 87.1% for 66 Gy group (p = 0.014). In multivariate analysis, radiation dose was a significant factor for LFFS (p = 0.015). Although radiation dose was not a significant factor for OS and disease-free survival (DFS) in multivariate analysis, both OS and DFS of 66 Gy group tended to be better than that of 45-63 Gy group in univariate analysis. However, there were no differences in severe toxicities among three groups. Conclusion: Higher radiation dose achieved better local control in patients with LS-SCLC treated with CCRT. In addition, a total dose of 66 Gy tended to improve OS and DFS.

Influence of Clinically Significant Portal Hypertension on Hepatectomy for Hepatocellular Carcinoma: a Meta-analysis

  • Tang, Yun-Hao;Zhu, Wen-Jiang;Wen, Tian-Fu
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.4
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    • pp.1649-1654
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    • 2014
  • Background: Clinically significant portal hypertension (PHT) is considered as a contraindication for hepatectomy according to the guidelines of the European Association for Study of Liver and the American Association for Study of Liver Diseases. However, this issue remains controversial. Here we performed a metaanalysis to evaluate the impact of PHT on the results of hepatectomy for hepatocellular carcinoma (HCC). Methods: Cohort studies evaluating the impact of clinically significant PHT, defined as oesophageal varices and/or splenomegaly associated with thrombocytopenia, on the results of hepatectomy for HCC were identified using a predefined search strategy. Summary risk ratios (RRs) and 95% confidence intervals (95% CIs) for PHT and outcomes after hepatectomy for HCC were calculated. Results: Seven cohort studies which including 574 cases with PHT and 1,354 cases without PHT were considered eligible for inclusion. The meta-analysis showed that, in all patients, pooled RRs of post-operative liver failure, post-operative ascites, peri-operative blood transfusion, operative mortality, 3- and 5-year overall survival associated with PHT were 2.23 (95% CI: 1.48-3.34, P=0.0001), 1.77 (95% CI: 1.19-2.64, P=0.005), 1.23 (95% CI: 1.03-1.49, P=0.03), 2.58 (95% CI: 1.12-5.96, P=0.03), 0.82 (95% CI: 0.75-0.88, P<0.00001) and 0.76 (95% CI: 0.69-0.85, P<0.00001), respectively. In subgroup analysis, similar results were found in Child-Pugh class A patients. Conclusion: This meta-analysis suggests that presence of oesophageal varices and/or splenomegaly associated with thrombocytopenia is associated with higher rates of post-operative complications and poor long-term survival after hepatectomy for HCC.