• Title/Summary/Keyword: impact stresses

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Bio-Economic Relationships between Climate Change and Fisheries (기후변화와 수산업의 관계에 관한 연구)

  • Park, Seong-Kwae;Kwon, Hyeok-Jun;Park, Jong-Wun;Cha, Cheol-Pyo
    • Journal of Fisheries and Marine Sciences Education
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    • v.22 no.3
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    • pp.388-401
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    • 2010
  • This research aims at analyzing impacts of climate change on fisheries. Climate change is an additional pressure on top of the many which fish stocks already experience. This implies that the impact of climate change must be evaluated in the context of other anthropogenic pressures, which often have a much greater and more immediate effect. Conversely, it is evident that fish stocks will be more resilient to climate impacts if the stresses due to other factors, such as over-fishing and pollution, are minimized. Improved management of fisheries and of marine ecosystems can undoubtedly play an important role in adapting to the impacts of climate change. Most of the improvements which are needed do not require new science or understanding, they require patient development of acceptable, effective, responsive social institutions and instruments for achieving adaptive management. Management advices must include complete and transparent information on risks and uncertainties which arise from data quality and from structural deficiencies in the assessment models. Well-designed and reliable monitoring of fish stocks and the marine ecosystem is essential in order to detect changes and give warning in advance of alterations in the productivity of individual species and of the structure and functioning of the ecosystem and fishery economy on which they depend.

A Study on Energy Eco-Audit Evaluation Scheme at Schools for Sustainable Energy Management (지속가능한 에너지 관리를 위한 학교 에너지 생태 감사 평가 방안 개발 연구)

  • Nam, Young-Sook
    • Hwankyungkyoyuk
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    • v.20 no.4
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    • pp.1-11
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    • 2007
  • The purpose of this study is to develope energy eco-audit evaluation scheme for the sustainable energy management at schools in accordance with education for sustainable development. Energy eco-audit evaluation scheme was developed through critical review of preexisting evaluation methods, consensus searching for the process from field. The results of this study are as follows. The school energy eco-audit evaluation scheme has three criteria: data collection, energy program, and environmental review. First, criteria of data collection includes general affairs, school building construction, and energy use. Second, criteria of energy program stresses school administration system such as the democratic decision-making process and structures. Third, criteria of environmental review includes reporting process and preparing teaching/learning materials for sustainable energy management. In conclusion, school energy eco-audit evaluation scheme could find a new way to achieve extended effect for sustainable energy management in school. It also could continue to seek opportunities to raise their awareness of energy issue and environment. School committee and whole school are involved to continue to implement present action plan and prepare updated plan in order to reduce environmental impact in school. By doing so, it would be possible to play important role in both school administration and education for sustainable development.

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A Study on the Structural Analysis & Design Optimization Using Automation System Integrated with CAD/CAE (통합된 CAD/CAE 자동화 System을 이용한 구조강도해석 및 설계최적화에 관한 연구)

  • Yoon J.M.;Won J.H.;Kim J.S.;Choi J.H
    • Korean Journal of Computational Design and Engineering
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    • v.11 no.2
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    • pp.128-137
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    • 2006
  • In this paper, a CAD/CAE integrated optimal design system is developed, in which design and analysis process is automated using CAD/CAE softwares for a complex model in which the modeling by parametric feature is not easy to apply. Unigraphics is used for CAD modeling, in which the process is automated by using UG/Knowledge Fusion for modeling itself and UG/Open API function for the other functions respectively. Structural analyses are also carried out automatically by ANSYS using the imported parasolid model. The developed system is applied for the PLS(Plasma Lighting System) consisting of more than 20 components, which is a next generation illumination system that is used to illuminate stadium or outdoor advertizing panel. The analyses include responses by static, wind and impact loads. As a result of analyses, tilt assembly, which is a link between upper and lower body, is found to be the most critical component bearing higher stresses. Experiment is conducted using MTS to validate the analysis result. Optimization is carried out using the software Visual DOC for the tilt assembly to minimize material volume while maintaining allowable stress level. As a result of optimization, the maximum stress is reduced by 57% from the existing design, though the material volume has increased by 21%.

Vibration Analysis at Bike Frame Fork (자전거 프레임 포크에서의 진동 해석)

  • Cho, Jae Ung;Han, Moon Sik
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.1
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    • pp.8-15
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    • 2014
  • This study investigates structural and vibration analyses for three types of bike frame fork models. As long as the maximum equivalent stresses of these models are lower than the yield stress, the three models are considered to be safe structurally. Type 3, with a maximum equivalent stress of 169.23 MPa, has the lowest stress among the three models and the strongest strength. Types 1, 2 and 3 have natural frequencies lower than 270 Hz. Type 3, with a critical frequency of 118 Hz, has the best durability under vibration among the three models. In order to decrease the vibration transmitted to a bike rider riding on a rough road, the impact due to vibration can be relieved by selecting a Type 3 model from among the three models. The results of this study can be effectively utilized for the design of a bike frame fork as this allows the anticipation and prevention of damage caused by durability issues.

The Impact of Southern Ocean Thermohaline Circulation on the Antarctic Circumpolar Current Transport

  • Kim, Seong-Joong;Lee, Bang-Yong
    • Journal of the Korean Geophysical Society
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    • v.9 no.4
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    • pp.291-299
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    • 2006
  • The observed ocean barotropic circulation is not completely explained by the classical wind-driven circulation theory. Although it is believed that the thermohaline forcing plays a role in the ocean barotropic circulation to some degree, how much the thermohaline forcing contributes to the barotropic circulation is not well known. The role of thermohaline circulation driven by changes in temperature and salinity in the Southern Ocean (SO) water masses on the Antarctic Circumpolar Current (ACC) transport is investigated using a coupled ocean - atmosphere - sea ice - land surface climate system model in a Last Glacial Maximum (LGM) context. Withthe implementation of glacial boundary conditions in a coupled model, a substantial increase in the ACC transport by about 75% in 80 years of integration and 25% in the near LGM equilibrium is obtained despite of the decreases in the magnitude of wind stresses over the SO by 33% in the transient time and 20% in the near-equilibrium. This result suggests that the increase in the barotropic ACC transport is due to factors other than the wind forcing. The change in ocean thermohaline circulation in the SO seems to play a significant role in enhancing the ACC transport in association with the change in the bottom pressure torque.

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Differently expressed genes of soybean by ambient heat stress

  • Jung, Inuk;Kim, Jin Hyeon;Jung, Woosuk
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.156-156
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    • 2017
  • Plants are grown under constitutive changing of environmental conditions and response to external conditions at both protein and transcription level. The effects of heat on plant growth are broad and influence the yield directly. Heat stresses could be classified depend on intensity and duration. Fundamental changes of growth condition by climate change maybe or maybe not classified as a stress on plant growth. The effects of a short and unanticipated impact of elevated heat on plant could be different with those of under longer extension of ambient heat. To examine differently expressed gene sets by ambient heat stress of soybean, we grow the soybean in normal condition for three weeks. After that, soybean plants move to growth chamber. The temperature of growth chamber increase up to $9^{\circ}C$ for four days. We have extracted mRNA and micro RNA every 24 hours and carried RNA sequence analysis. We found major metabolic pathways affected by ambient heat stress. Mainly carbon metabolism, translation machinery and amino acid synthesis are affected. We discussed the expression patterns of genes of heat sensing and hormone responses.

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Evaluation of Reactor Internals Integrity due to 5.5m Concentric Free Fall of KSNP+ Reactor Vessel Closure Head (KSNP+ 원자로덮개 5.5m 수직 낙하 시 원자로내부구조물 건전성 평가)

  • Namgyng, Ihn;Jeong, Seung-Ha;Lee, Dae-Hee;Choi, Taek-Sang
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1358-1363
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    • 2003
  • Due to the application of Integrated Head Assembly (IHA) in KSNP+ reactor design, an investigation of reactor internals integrity is carried out to assure that the adoption of IHA does not affect the safety of reactor operation. One of the postulated accident events is the R.V. closure head fall from 5.5m high directly above the reactor vessel that may occur during the refueling operation. The analysis model consists of lumped mass elements of the entire reactor vessel and internals. Because of extreme load, separate elastic-plastic analyses are done for the members that undergo plastic deformation. The analysis verified that the stresses of the reactor internals and the fuel assemblies are within the bound of allowable stress limits and the integrity of the fuel assemblies is maintained.

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Identification of functional SNPs in genes and their effects on plant phenotypes

  • Huq, Md. Amdadul;Akter, Shahina;Nou, Ill Sup;Kim, Hoy Taek;Jung, Yu Jin;Kang, Kwon Kyoo
    • Journal of Plant Biotechnology
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    • v.43 no.1
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    • pp.1-11
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    • 2016
  • Single nucleotide polymorphism (SNP) is an abundant form of genetic variation within individuals of species. DNA polymorphism can arise throughout the whole genome at different frequencies in different species. SNP may cause phenotypic diversity among individuals, such as individuals with different color of plants or fruits, fruit size, ripening, flowering time adaptation, quality of crops, grain yields, or tolerance to various abiotic and biotic factors. SNP may result in changes in amino acids in the exon of a gene (asynonymous). SNP can also be silent (present in coding region but synonymous). It may simply occur in the noncoding regions without having any effect. SNP may influence the promoter activity for gene expression and finally produce functional protein through transcription. Therefore, the identification of functional SNP in genes and analysis of their effects on phenotype may lead to better understanding of their impact on gene function for varietal improvement. In this mini-review, we focused on evidences revealing the role of functional SNPs in genes and their phenotypic effects for the purpose of crop improvements.

Influence of the roof lithological characteristics on rock burst: a case study in Tangshan colliery, China

  • Jienan, Pan;Zhaoping, Meng;Quanlin, Hou;Yiwen, Ju;Guofu, Li
    • Geomechanics and Engineering
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    • v.1 no.2
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    • pp.143-154
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    • 2009
  • Many factors influence occurrences of rock burst in coal mines, such as mining methods, control methods of the coal roof, lithological characteristics of the roof and floor, tectonic stress, groundwater and so on. Among those factors, lithological characteristics in the roof are the intrinsic controlling factors that affect rock burst during coal mining. Tangshan colliery is one of the coal mines that have suffered seriously from rock bursts in China. In this paper, based on the investigating the lithological characteristics of coal roofs and occurrence of rock bursts in Tangshan colliery, a numerical method is used to study the influence of roof lithological characteristics on rock burst potential. The results show that the lithological characteristics in the roof have an important impact on the distributions of stresses and elastic strain energy in coal seams and their surrounding rocks. Occurrences of rock bursts in this colliery have a close correlation with the thick-bedded, medium- to fine-grained sandstones in the roof. Such strata can easily cause severe stress concentration and accumulate enough energy to trigger rock bursts in the working face during mining operations.

Analysis on the Ballistic and Blast Shock for a Space Frame Structure (내충격 개방형 구조물에 대한 피탄 및 폭압 충격 해석)

  • Joo, Jae-Hyun;Gimm, Hak-In;Koo, Man-Hoi;Park, Jee-Woo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.5
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    • pp.933-940
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    • 2010
  • A numerical analysis for the space frame structure under ballistic and blast loads was performed using LS-DYNA, a commercial code. The space frame structure was developed to be adapted to the ground vehicle in the future and it was designed to build with Al7039 frames and lightweight multi-layered panels for the purpose of weight reduction and shock mitigation. The analyses have done for side impacts by a cylindrical projectile and Comp. C-4 explosive representing major threats to the vehicle. The deformed shape of the panel section and stresses as well as accelerations of the frames calculated from LS-DYNA were compared to the test results to validate the analysis model. The internal energies for panels and frames from LS-DYNA were also compared to each other to discern their role in absorbing the ballistic and blast impact.