• 제목/요약/키워드: Stress Deviation

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유한요소해석을 이용한 디스크 커플링의 토크전달 능력에 대한 연구 (A Study on the Torque Transmitting Capability of a Disk Coupling by Finite Element Analysis)

  • 서원상;김성묵;김종봉
    • 한국정밀공학회지
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    • 제30권11호
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    • pp.1171-1177
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    • 2013
  • In this study, the torque transmitting capability of a flexible disk coupling was investigated. Flexible disc coupling is used to transmit power between two axes, and there exist mis-alignments such as angle of deviation and end play between two shafts. A disk is an important part in the flexible disk coupling because the disk has to transmit power between two mis-aligned shafts. To investigate the effect of mis-alignment on load carrying capacity, finite element analyses were carried out. Analyses were carried out for two types of disk; i.e., circular and square disks. The rotational and bending stiffness of disk plates was predicted to investigate the effect of mis-alignment on stress. As a result, it was shown that the mis-alignment can cause severe decrease in load-carrying capacity. And, the square disk showed better performance than the circular disk.

성인의 건강행위 변화단계와 건강관련 삶의 질에 대한 연구 (Stages of Health Behavior Change and Health Related Quality of Life among Korean Adults)

  • 김애경
    • 기본간호학회지
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    • 제14권2호
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    • pp.230-238
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    • 2007
  • Purpose: The Transtheoretical Model (TTM) is a theoretical construct explaining stages of health behavior change. The purpose of this study was to describe and analyze the stages of health behavior change and health related quality of life (HRQL), Method: A descriptive survey design was utilized, and, using a questionnaire, which included a series of 5 questions designed to assess stages of health behavior change and HRQL instrument, data were collected from 292 adults. Means, standard deviation, t-test, ANOVA, and SNK test were used to analyze the collected data. Results: Health risk behaviors were lack of stress management(44%), alcohol use (42.5%), poor nutrition (37%), smoking (36.3%), a lack of spirituality (28.8%), poor communication skills (21.9%), Lack of safety(21.6%), lack of fittness (20.1%), violent behavior(12.3%), and drug use(6.8%). There was a significant difference in HRQL according to stage of health behavior change (P=0.001). Conclusion: The results of the study identified the need for individualized nursing interventions that based on the stage of health behavior change. Nursing interventions that focus on the stage of health behavior change would be effective for health promotion for Koreans.

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기 손 반사요법이 입원환자의 자율신경계 활성도와 스트레스 저항도에 미치는 영향 (Effects of Qi Hand Reflexology on Autonomic Nervous System Activity and Physical Resistance to Stress in Inpatients)

  • 오세영;박옥순;우명이
    • 기본간호학회지
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    • 제17권4호
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    • pp.531-538
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    • 2010
  • Purpose: This study was done to identify the effects of Qi hand reflexology on autonomic nerve activity in patients admitted to hospital. Method: A non-equivalent control group and quasi-experimental research with pre/post test design were used and 59 patients on a medical ward were assigned to either the experimental group (32) or the control group (27). The study variables included vital signs, autonomic nerve activities (ALF (absolute low frequency), AHF (absolute high frequency), nLF (normalized low frequency), nHF (normalized high frequency), SDNN (standard deviation of all normal-normal intervals)) and were evaluated using the QECG-3 system. The experimental group was treated with Qi hand reflexology for 10 minutes per day, for 3days. Results: Skin temperature and systolic blood pressure in the experimental decreased with treatment. ALF, AHF and SDNN for the experimental group increased with regulating proportion (nLF: nHF=6:4) and a significant difference between the groups was observed. Conclusion: The results indicated that application of Qi hand reflexology for patients in the hospital is effective in regulating the autonomic nervous system activation. Implication of finding should be useful for future research.

전단류 하중을 받는 상부장력 라이저의 동적 응답 해석 (Dynamic Response Analysis of Top-tensioned Riser Under Sheared Current Load)

  • 김국현
    • 한국해양공학회지
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    • 제27권4호
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    • pp.83-89
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    • 2013
  • A numerical scheme based on a mode superposition method is presented for the dynamic response analysis of a top-tensioned riser (TTR) under sheared current loads. The natural frequencies and mode shapes of the TTR have been calculated analytically for a beam with a slowly varying tension and pinned-pinned boundary conditions at the top and bottom ends. The lift coefficients and corresponding amplitudes used to estimate the vortex-induced modal force and damping for each mode were predicted via iterative calculations based on the input and output power balancing concept. Here, the power-in regions were controlled by the normal distribution function, for which the center was coincident with the lock -in location by local vortex-shedding, and the range was defined by the constant standard deviation for the reduced velocity by the local current speed. Finally, dynamic responses such as root-mean-squared displacement and stress were calculated using the mode superposition technique. In order to verify the presented scheme, a numerical calculation was performed for a TTR under an arbitrary linearly sheared current and linearly varying tension. A comparison with the results of the existing software showed that the presented scheme could give reliable and feasible solutions. Case studies were performed to investigate the effects of various current loads and tensions.

직무요구와 직무자원이 병원행정직 간호사의 소진과 조직몰입에 미치는 영향 (The Effects of Job Demand and Job Resources on Burnout and Work Engagement of Hospital Nurse Administrators)

  • 차우정;김숙영
    • 한국직업건강간호학회지
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    • 제29권4호
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    • pp.262-272
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    • 2020
  • Purpose: This study aims to investigate the degree of job demand, job resources, burnout, and the organizational commitment of administrative nurses based on the job demands-resources model. Further, it seeks to confirm the influencing factors affecting nurses' burnout and organizational commitment. Methods: The participants were 188 administrative nurses working at hospitals (one tertiary hospital and six general hospitals) located in D City. The collected data were analyzed with IBM SPSS Statistics 23.0 using frequency, percentage, mean, standard deviation, t-tests, ANOVA, Pearson's correlation coefficient, and multiple regression analysis. Results: The influential factors of burnout were role conflict (β=.50), job demand (β=.18), job position (β=-.17, team leaders and above), and social support (β=-.15). The regression model had an explanatory power of 59%. The influential factors of organizational commitment were appropriate rewards (β=.59), job position (β=.15, team leader or above), working department (β=.14, referral center and health screening administration department), and social support (β=.18). The regression model had an explanatory power of 59.5%. Conclusion: The results support the job demands-resources model, and interventions should be developed to decrease job demand and provide sufficient job resources.

Al합금의 사각용기 딥드로잉시 주름의 거동에 관한 연구 (A Study on the Behavior of Wrinkling in the Square Cup Deep Drawing of Al Alloy)

  • 고대림;정동원
    • 대한기계학회논문집A
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    • 제33권3호
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    • pp.276-282
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    • 2009
  • Wrinkling in the flange and wall of a deep-drawn part is one of the major defects in sheet metal processes. Wrinkling is influenced by many factors, such as material properties, shape of the body, forming conditions, stress state and thickness, etc. It is difficult to analyze the wrinkling initiation and growth according to the factors because the effects of the factors are very complex and the wrinkling behavior may show wide variation even though small deviation of factors. In this study, the influence of wrinkling parameters, such as material properties (Al1050, Al5052), the blank holding force and the drawing depth on the wrinkling initiation and growth is investigated by using the experimental method and the dynamic explicit finite element analysis. From the results, it is shown that the dynamic explicit finite element method can be used effectively to prevent the wrinkling problems advancely in the deep drawing process. Also, there is a good agreement between the experimental result and the dynamic explicit finite element analysis.

통계적 유한요소모델을 이용한 발포된 금속기지 복합재료의 인장특성 (Tensile Behaviour of Foamed Metal Matrix Composite Using Stochastic FE Model)

  • 전성식
    • Composites Research
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    • 제17권2호
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    • pp.34-39
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    • 2004
  • 본 연구에서는 폐쇄형 발포금속의 인장 특성을 이해하기 위하여 수정된 단위모델을 제시하였다. 또한 발포금속의 밀도는 가우스 분포에 의거하여 확률적으로 분포한다고 가정하고 본 연구에서 제시된 수정 단위 모델을 조합하여 유한요소 모델을 제안하였다. 이 모델은 실제 인장 시험과 유사한 변형거동을 보이는 것을 확인하였고, 적절한 밀도 분포와 내부 기공을 고려하게 되면, 해석에서 구해진 최대 인장 강도가 근사적으로 실험결과와 일치하는 것을 볼 수 있었다. 또한, 발포 알루미늄의 최대 인장 강도는 밀도 분포의 표준편차보다는 내부 기공 부피분율에 더 민감하게 변하는 것으로 밝혀졌다.

취업주부의 직업-가정 갈등, 가사노동사회화, 그리고 가정관리만족간의 인과관계 (Causal Relationships among Working Wives' Work-Family Conflict, Socialization of Housework, and Home Management Satisfaction)

  • 임혜경
    • 대한가정학회지
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    • 제33권3호
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    • pp.85-99
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    • 1995
  • The major purpose of this research was to investigate the causal relationships among working wives' work-family conflict, socialization of housework, and home management satisfaction. the double ABCX model of family stress and adaptation provided the theoretical framework for this study. the data were recruited from working wives who had more than one pre-school child. The respondents were asked to complete the self-administered questionnaires, and the responses of 536 working wives were used for the final analysis. basically Cronbach's α to the reliability of major variables, frequencies, percentages, means, standard deviation, pearson's correlation coefficients, and LISREL 7 program were performed to test the research model. The results of this study can be summarized as follows : 1. The frequency of work-family conflict was affected by the flexibility of work time and wives' income. 2. The severity of wok-family conflict was directly influenced by the frequency of the conflict, the flexibility of work-time, and wives' education level. 3. The variables influencing the degree of socialization of housework were found to be the frequency and the severity of work-family conflict, wives' education, and the degree of husband's participation in housework. 4. The higher degree of home management satisfaction was associated with the higher level of family member's health status, the greater degree of the flexibility of work-time, and the greater degree of husband's participation in household labor.

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탄.소성 구성 모델의 초질매개변수 예민성 (Sensitivity of Parameters for Elasto-plastic Constitutive Model)

  • 정진섭;김찬기;이문수
    • 한국지반공학회지:지반
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    • 제8권2호
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    • pp.81-96
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    • 1992
  • 본 문은 Lade의 단일항복면 구성모델(single work-hardening model)을 선정하여 사질토의 거동해석에 필요한 토질매개변수를 실내시험을 하여 구하는 과정에서 필연적으로 발생하는 실험오차가 해석결과에 미치는 영향을 분석하였다. 연구방법으로서는 백마강 모래에 대하여 등방압축-팽창시험과 구속압력을 달리한 일련의 배수삼축시험을 하고 이 시험자료를 이용하여 회귀분석을 근거로, 본 연구에서 개발된 토질 매개 변수 결정 프로그램에 의해 기찬매개변수를 결정하고 그 평균치에서 표준편차를 증감시켜 축방 향변형률에 대한 축차응력 및 체적변형률의 상계 및 하계 범위를 밝힘으로서 각 토질매개변수의 민감도를 규명하였다. 그 결과 토질매개변수결정 프로그램의 실용성이 크다는 것을 화인하고 Lade의 단일항복면 구성모델의 예측능력이 좋다는 것을 알았다.

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맥동 유동 발생을 위한 맥동 펌프의 설계 및 특성 분석 연구 (Design of pulsatile pump and performance test for pulsatile flow generation)

  • 주윤하;김경원;이연호;곽문규;이춘영;이종민;박철우
    • Journal of Advanced Marine Engineering and Technology
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    • 제37권2호
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    • pp.149-155
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    • 2013
  • 혈류 유동 연구를 위해서는 심장의 맥동 유동을 만들어 내는 것이 중요하다. 본 연구에서는 동맥혈류의 유동 해석을 위해 새롭게 설계된 심장 박동 모사 맥동펌프의 제작 및 그 성능에 관하여 시험을 수행하였다. 피스톤 펌프를 이용한 기본몸체 설계를 수행하였고 직류모터와 엔코더를 사용하여 회전수와 가속비를 설정할 수 있도록 하였으며, 시험결과는 전 영역에서 맥동 유동의 분포를 잘 따르고, 반복되는 맥동 주기의 편차도 작게 나타남을 확인하였다.