• 제목/요약/키워드: Challenge Stress

검색결과 183건 처리시간 0.022초

단결정 철의 소성에 대한 멀티스케일 모델링 (Multi-scale Modeling of Plasticity for Single Crystal Iron)

  • 전종배;이병주;장영원
    • 소성∙가공
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    • 제21권6호
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    • pp.366-371
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    • 2012
  • Atomistic simulations have become useful tools for exploring new insights in materials science, but the length and time scale that can be handled with atomistic simulations are seriously limiting their practical applications. In order to make meaningful quantitative predictions, atomistic simulations are necessarily combined with higher-scale modeling. The present research is thus concerned with the development of a multi-scale model and its application to the prediction of the mechanical properties of body-centered cubic(BCC) iron with an emphasis on the coupling of atomistic molecular dynamics with meso-scale discrete dislocation dynamics modeling. In order to achieve predictive multi-scale simulations, it is necessary to properly incorporate atomistic details into the meso-scale approach. This challenge is handled with the proposed hierarchical information passing strategy from atomistic to meso-scale by obtaining material properties and dislocation mobility. Finally, this fundamental and physics-based meso-scale approach is employed for quantitative predictions of the mechanical response of single crystal iron.

강인성 (hardiness)에 대한 문헌고찰 (The Concept of Hardiness : A Review of the Literature for Nursing)

  • 박명희
    • 대한간호학회지
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    • 제22권2호
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    • pp.227-237
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    • 1992
  • The purposes of this literature review were to identify the theoretical basis and components of the concept hardiness, trends in the study of hardiness it's application in nursing and issues in measurement. The concept of hardiness has been derived deductively from existential psychology and is composed of three components, control, commitment and challenge. In research, the characteristic of hardiness has been demonstrated as a motivating factor in resolving stressful situations and in adapting to actual health problems. With regard to the measurement of hardiness, because of it's low level of predictability related to health outcomes, it is recommanded that the component of be omited from the concept of hardiness. On the basis of this literature review, the following suggestions are proposed. 1. Considering the lack of empirical suport, the theory of hardiness needs to be evaluated. 2. There is a need for further study of hardiness in a broad variety of populations. 3. A valid, reliable and culturally appropriate instrument needs to be developed for health related research. 4. Analysis is needed of the relationship between hardiness and stress-resistance, and of the factors related to both.

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정사각 실린더 주위 비정상 난류 유동에 대한 수치적 연구 (Numerical Study on Unsteady Turbulent Flow Around Square Cylinder)

  • 이호준;유병훈;이창훈;최정일
    • EDISON SW 활용 경진대회 논문집
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    • 제1회(2012년)
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    • pp.69-72
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    • 2012
  • 본 연구에서는 정사각형으로 모델링된 실린더 주위에 균일한 유동이 흐를 때 나타나는 이차원 난류 유동을 분석하였다. EDISON-CFD를 이용하여 정사각 실린더 표면에서의 전단응력 분포 및 유동 현상을 시뮬레이션 하였다. 선행 연구 결과의 $\bar{C_D}$, ${C_L}^{\prime}$ 값과 비교하여 결과의 유효성을 검증하였다. 또한, 비정상 층류 유동(Re=100)과 비교하여 난류 유동(Re=22,000)의 특성을 분석하였고, 와 흐름에 의하여 정사각 실린더 표면이 받는 전단응력을 자세히 분석하였다.

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2way 가드레일의 형상에 관한 연구

  • 양선웅;김세일;신상준
    • EDISON SW 활용 경진대회 논문집
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    • 제6회(2017년)
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    • pp.346-350
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    • 2017
  • 고속도로에서 자주 사용되고 있는 2way 가드레일 형상의 효율성을 탐구해보기 위하여 가드레일 형상과 이와 단면적이 같은 여러 종류의 단면을 가진 보들과 응력 값을 비교하였다. vonMises stress값의 비교를 통해 기존 가드레일의 W모양 단면과 경제적으로는 동일하고 형태는 상이하며 구조적으로 더 안정적인 단면 형상을 찾아보고자 한다. 그 결과 2way 단면의 가드레일 보다는 반원 단면의 가드레일이, 두께가 4T인 2way 모델 보다는 3T인 모델의 안전계수가 더 높음을 확인하였다. 이를 통해 향후 가정이 없는 실제 상황에서는 어떠한 이유 때문에 2way 가드레일 형상을 사용하고 3T보단 4T, 5T를 보편적으로 사용하는지 연구해보면 좋을 듯 하다.

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능동 비틀림 제어에 용이한 블레이드의 스파형상 선정

  • 배재성;신명승
    • EDISON SW 활용 경진대회 논문집
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    • 제4회(2015년)
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    • pp.184-190
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    • 2015
  • On wide variety of fields, studies on active twist control are becoming more active. For effective twist control, blades have to have low torsional stresses with high torsional deformations to the same magnitude of torque acting on its cross-section. In this study, 2D sectional analysis and 3D finite element analysis were made for 5 different blades with each having different cross - sections which have different spars. The results from 2D sectional analysis, were then put into 3D blade deformation and stress calculations which lead to analysis. Outcomes from 2D and 3D analysis, showed that on the same torque and concentrated load conditions, the blade with 'C' shaped spar was the best of all the blades which were used in this study.

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구조 형태에 따른 1차원 보와 2차원 평판 구조 해석 비교

  • 강유진;심지수
    • EDISON SW 활용 경진대회 논문집
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    • 제4회(2015년)
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    • pp.274-278
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    • 2015
  • There are different kinds of aircrafts, such as conventional airplane, rotorcraft, fighter, and unmanned aerial vehicle. Their shape and feature are dependent upon their assigned mission. One of the fundamental analyses during the design of the aircraft is the structural analysis. The structural analysis becomes more complicated and needs more computations because of the on-going complex aircrafts' structure. In order for efficiency in the structural analysis, a simplified approach, such as equivalent beam or plate model, is preferred. However, it is not clear which analysis will be appropriate to analyze the realistic configuration, i.e., an equivalent beam or plate analysis for an aircraft wing. It is necessary to assess the boundary between the one-dimensional beam analysis and the two-dimensional plate theory for an accurate structural analysis. Thus, in this paper, the static structural analysis results obtained by EDISON solvers were compared with the three-dimesional results obtained from MSC NASTRAN. Before that, EDISON program was verified by comparing the results with those from MSC NASTRAN program and analytic solution.

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족저근막염에 대한 임상적 고찰 (A Clinical study on plantar fasciitis)

  • 정병옥
    • 대한정형도수물리치료학회지
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    • 제7권2호
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    • pp.57-64
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    • 2001
  • Plantar fasciitis is a common pathological condition of the foot and often be a challenge for clinicans to successfully treat. The purpose of this article is to present and discuss selected literature on the function and anatomy, causes, symptoms and clinical treating methods of plantar fasciitis. A majority of patients with plantar fasciitis present with either a pronated or a cave foot. Pain is usually localized to the plantar medial heel at the attachment of the plantar fascia to the calcaneus. Surgical and nonsurgical techniques have been used in the treatment of plantar fasciitis. Nonsurgical management for the treatment of the symptoms and discomfort associated with plantar fasciitis can be classified into brod categories: reducing pain and inflammation. reducing tissue stress to a tolerable level, and restoring muscle strength and flexibility of involved tissue.

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아동상담자의 의욕상실에 영향을 미치는 상담 및 업무환경 변인 (Effects of the Counseling and the Working Environment on Burnout in Child Counselor)

  • 박희현;김광웅
    • 아동학회지
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    • 제27권4호
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    • pp.201-218
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    • 2006
  • Using an instrument validated in an antecedent study, this study explored the effect of counseling and working environment variables on burnout in child counselors. The 191 counselors of this study worked with children under 18 years of age. Data were analyzed by Cronbach's a, quantification methods I. Counseling and working environment variables have 33% of ad-$R^2$ over the total score of burnout in child counselors. Variables contributing to burnout were workload, position in an institution, income from counseling, theoretical approach, and job stress. Counselors with 1-5 cases per week, working independent of an institution and using a single theory of counseling experienced more burnout, and counselors without challenge on the job, excessive role conflict, role ambiguousness, and excessive workload experienced more burnout.

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Protective Effect of Copper against Pancreatic Insult in Streptozotocin-induced Diabetogenic Rat

  • Kim, Hyoung-Chun;Jhoo, Wang-Kee;Kim, Kyeong-Ho;Kim, Jin-Tae;Lee, Sang-Joon;Hur, In-Hoi
    • Archives of Pharmacal Research
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    • 제13권2호
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    • pp.121-125
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    • 1990
  • The present study examined the alterations in endogenous oxy-radical scaverging system of pancreatic tissue associated with the dose of 45 mg/kg steptozotocin (STZ) alone or with various combinations. The activities of pancreatic Min-superoxide dismutase (SOD) and catalase were no apparent changes in the other groups except for the Cu(II) 4 mg/kg pretreated group. The presence of 4 mg/kg of Cu(II) with or without 125 mg /kg of diethylenetriaminepentaacetic acid (DTPA) markedly attenuated the fall in activity of Cu, Zn-Sod by STZ stress. In particular, STZ-induced superoxide generation was dramatically abolished by prior administration of Cu(II) 4 mg/kg. Conculsively, We suggested the possible involvement that copper may enhance the defence mechanism of pancreatic oxidative damage by STZ challenge.

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내부에너지를 최대로 하는 활 구조의 최적화 (Shape optimization of a bow for maximizing internal-energy)

  • 문명조;이현정
    • EDISON SW 활용 경진대회 논문집
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    • 제5회(2016년)
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    • pp.222-227
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    • 2016
  • In this paper, the optimized design for bow structure was investigated by using EDISON software. Considering the mechanism of the bow, non-linear FEM analysis was essential. The factors of the design are height, width, number of holes and taper value. High performance of the internal energy and lowest mass were main issues. The limit of the von-mises stress was yield strength for the material. Material was chosen by considering typical bow material, Aluminum. Using Taguchi method($L_9$), 9 models were selected and contribution rate was calculated for each factors. Following the contribution rate, 3 factors were fixed and optimized model was predicted. After making optimized model for FEM analysis, the value of internal-energy, mass for FEM model were compared with predicted value, calculated the percentage error and figure out the reliability of Taguchi method.

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