• Title/Summary/Keyword: Stress relief

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Analysis of Practical Dynamic Force of Structure with Inverse Problem (역문제에 의한 구조물의 실동하중 해석)

  • 송준혁;노홍길;김홍건;유효선;강희용;양성모
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.2
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    • pp.75-80
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    • 2004
  • Vehicle structures are composed of many substructure connected to one another by various types of mechanical joints. In vehicle engineering it is important to study these connected structures under various dynamic forces for the evaluations of fatigue life and stress concentration exactly. It is difficult to obtain the accurate load history of specified positions because of the errors such as modeling, measurement and etc. In the beginning of design exact load data are actually necessary for the fatigue strength and life analysis to minimize the cost and time of designing. In this paper, the procedure of practical dynamic force determination is developed by the combination of the principal stresses of F. E. Analysis and experiment. Least square pseudo inverse matrix is adopted to obtain in inverse matrix of analyzed stresses matrix. The error minimization method utilizes the inaccurate measured error and the shifting error that the whole data is stiffed over real data. The least square criterion is adopted to avoid these non. Finally, to verify the proposed procedure, a bus is analyzed. This measurement and prediction technology can be extended to the structural modification of any geometric shape in complex structure.

Phase Formation Behavior of Mechanical Alloyed Al-25at% Nb Powder Mixtures (기계적 합금화에 의한 Al-25at%Nb 혼합분말의 상형성 거동)

  • 이상호;김동관;이진형
    • Korean Journal of Materials Research
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    • v.5 no.8
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    • pp.997-1004
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    • 1995
  • Intermetallic compound NbAl₃and amorphous phases were synthesized by mechanical alloying of elemental powder mixtures of niobium and aluminum. The composition of the powder mixtures was Nb-45wt%Al(75at%Al). The mechanical alloying was performed with a high energy SPEX 8000 mixer/mill up to 72 hrs. The resulting powders were analyzed by XRD, DTA, SEM and TEM. The mechanically alloyed powders exhibited lamellar structures in the early stage. And the elements of Nb and Al were homogeneously distributed over the Powder when a steady state was reached. An intermetallic compound, NbAl₃, was formed by mechanical alloying for 4 hrs. The mechanically alloyed powders exhibited a large exotherm around 600℃, corresponding to formation of stable NbAl₃and stress relief.

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The Moderating Effects of Social Support between Emotional Labor and Job Satisfaction in Clinical Nurses (임상간호사의 감정노동과 직무만족 간의 관계에서 사회적 지지의 조절효과)

  • Han, Hye-Yul;Lee, Ji-Young;Jang, Insun
    • Korean Journal of Occupational Health Nursing
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    • v.24 no.4
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    • pp.331-339
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    • 2015
  • Purpose: The purpose of this study was to investigate the moderating effects of social support between emotional labor and job satisfaction in clinical nurses. Methods: Participants were 311 clinical nurses and data were collected from July 11th to 18th, 2014. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation coefficient and hierarchical multiple regression with SPSS 21.0. Results: The job satisfaction indicated a significant relationship to surface-acting (r=-.191, p=.001), deep-acting (r=.179, p=.002) and social support (r=.342, p<.001) respectively. Emotional labor significantly affected job satisfaction (F=11.592, p<.001), and explained 5.4% of the variance in job satisfaction. The social support acted as a moderator on the relationship between emotional labor and job satisfaction at significant level (F=11.416, p<.001). Conclusion: The results of this study suggest that it is important to develop social support promoting and stress relief program for clinical nurses to improve job satisfaction.

Relations between Fatigue and Work-related Factors in Workers (일개 생산직 근로자들의 작업수행과 피로도와의 관계)

  • Jung, Eun-Sook;Cha, Nam-Hyun
    • Research in Community and Public Health Nursing
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    • v.22 no.4
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    • pp.420-428
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    • 2011
  • Purpose: The purpose of this study was to investigate the relations between fatigue and work-related factors in workers. Methods: A total of 204 subjects aged between 21 and 59 were selected through convenient sampling. Data were collected with a self-reported questionnaire from May 20 to 31, 2011. Collected data were analyzed with SPSS/WIN 17.0. Results: Difference in fatigue according to general characteristics was significant according to duty type. Difference in fatigue according to occupational characteristics was significant according to work intensity, work speed, demand of work concentration, work space, physical environment, largest weight by hands, vibration, visual demand of work, difficulty of work practice, work stress, and rest hours in holiday. There was a positive correlation between fatigue and occupational characteristics. Stepwise multiple regression analyses showed that educational level, work intensity, and rest hours in holiday were the strongest factors associated with fatigue ($R^2$=.363 p<.001). These factors explained fatigue by 36.3%. Conclusion: The findings of this study may be useful in understanding workers' fatigue and developing more specific fatigue relief programs.

Thermal Characteristics Analysis by Ambient and Operating Temperature according to the Kinds of Terminations in Underground Power Cable Systems (지중송전케이블 종단접속함 종류에 따른 외기 및 운전온도에 의한 열특성 분석)

  • Jung, Chae-Kyun;Kang, Ji-Won;Lee, Bang-Wook
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.8
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    • pp.1154-1160
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    • 2015
  • This paper describes the thermal characteristics of underground power cable system terminations according to the change of ambient temperature as well as operating temperature. Recently, the failure has been gradually increasing in outdoor termination during winter season because the power demand was increased by electricity heating system. The power demand and outdoor temperature is difference between day time and night time. The temperature difference has an influence on conductor extension and shrinkage due to conductor force as well as thermal mechanical characteristics. These phenomena have daily repeated during heating and cooling period of conductors. In these cases, the insulation of outdoor terminations might be degraded by the reduced interface pressure surrounding stress relief cone. Therefore, in this paper, the thermal characteristics are variously analysed by simulation considering power demand and ambient temperature condition during winter season at epoxy type termination as well as slip-on type termination

A Study on the Fashion Illustration of Humor Images Using 2D Graphics (2D 그래픽스를 활용한 유머 이미지의 패션일러스트레이션 연구)

  • Kim, Hye-Ran;Kim, Soo-Kyong
    • Journal of the Korean Society of Costume
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    • v.58 no.9
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    • pp.81-98
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    • 2008
  • This research aims to analyze humorous images expressed in 2D graphics fashion illustrations and to propose application of 2D graphics in humorous images for fashion illustrations to suggest a more creative and relevant fashion illustration for contemporary culture. The result of this research were as follows: First, theories on reaction of humor can be classified into Incongruity theory, Superiority theory and Arousal and Relief theory. Humor in visual arts are classified in Visual Parody, Visual Pun, Visual Paradox and Visual Satire. Second, Visual Pun, Visual Parody, and Visual Satire are used for visualizing fashion illustration, and the foundations for many humor images were simple-colored, imaginative, and unreal settings. And it was also found out that the physical proportion of the models generally was 1(head):7(entire body), 1:8, 1:15 and the models were usually laughing and smiling. Tone was usually pastel and vivid, and posture was usually standing-position or sitting-position. Third, based on such results, fashion illustration works of humor image using 2D graphics were created. To concretize the humor image, 'gift' as a concept was chosen. Humor alleviates the tension and stress. It also brings laughter and pleasure to people's lives. Therefore humor image will be an effective way of expanding creativity in modern fashion illustration.

Social function of game as a leisure activity (여가 문화 활동으로서 게임의 사회적 기능)

  • Ryu, Seuc-Ho;Lee, Wan-Bok
    • Journal of Digital Convergence
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    • v.10 no.7
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    • pp.245-251
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    • 2012
  • The significance of this study lies in the fact that it looks into the function of games as one of the important leisure activities at the moment when negative perception on overall game industry is becoming an obstacle in settlement of sound game culture. Game is one of the activities enjoyed in leisure time. The main positive effects of game were analyzed classifying them into 10 types including the stress relief and alleviation of tension, diverse identity experience and positive socialization experience, strengthening of self-respect and ideal self-realization, strengthening of independent thinking and problem-solving capacity, motivation for learning, enhancement in physical capacity, decrease in aggressive tendencies, cultivation of awareness on equality, increase in familiarity with the civilization of technology, and strengthening of individuality based on diversity.

Comparison of the Dietary Factors between Normal and Constipation Groups by Self-reported Constipation in Female College Students (자의적 변비 분류에 의한 정상군과 변비군 여대생의 식사관련 요인 비교)

  • Lee, Chae-Rin;Kim, Soon-Kyung
    • Korean Journal of Community Nutrition
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    • v.16 no.1
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    • pp.23-36
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    • 2011
  • The purpose of this study was to obtain baseline data on dietary management of women's constipation. We estimated the prevalence of self reported constipation, bowel habits and foods & nutrients intake. The subjects were 169 female college students (normal = 92, constipation group = 77) aged 19 to 23 years. We conducted anthropometric measurements, an evacuation habits survey, and a dietary intake assessment for three days by a 24 hour recall method. The prevalence of self reported constipation was 46% (n = 77). Results showed that bowel habits (the difficulty of evacuation, the duration of evacuation and the feeling after evacuation) were significantly different between the two groups. Over 65% of constipation group used laxatives for constipation relief. Frequency of stress and deep sleeping were related with constipation. In daily food consumption and nutrients intake, there was not a significant difference between the groups. However in relation to bowel habits which factors influence constipation, the study showed that the intake of water, potatoes, kimchi, and fruits correlated with evacuation facility. Further, there were no findings in the difference of foods consumption and nutrients intake between the two groups. But some life style changes and food intakes (potato and kimchi) may be useful to improve constipation symptoms in young women.

The effects of therapeutic ultrasound stimulation on the inflammation cytokine in rat articular chondrocytes

  • Kim, Eun-Jung;Hwang, Sujin;Kim, Gye-Yeop
    • Physical Therapy Rehabilitation Science
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    • v.2 no.1
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    • pp.21-26
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    • 2013
  • Objective: The aim of this study was to investigate the effect of therapeutic ultrasound (US) of cell viability and inflammatory cytokine in rat articular chondrocyte cultures stimulated with lipopolysaccharide (LPS). Design: One group pretest-posttest design. Methods: Cultured chondrocytes were treated with US and/or LPS and assessed for viability, Tumor necrosis factor $(TNF)-{\alpha}$ and Interleukin (IL)-1 production. Results: Oxidative stress was induced in rat chondrocytes with LPS. The cell viability was decreased in chondrocytes after treatment with LPS. The viability revealed that low-intensity pulsed ultrasound (LIPUS) exerted no significant cytotoxicity in the rat chondrocyte. LIPUS inhibited decreased cell viability in the presence of LPS ($30{\mu}g/ml$) in a intensity dependent pattern at LIPUS (p<0.05). $TNF-{\alpha}$ production in the presence of LPS was also inhibited in a dose dependent manner (p<0.05 from $30mW/cm^2$). IL-1 production in the presence of LPS was inhibited as well (p<0.05 from $7.5mW/cm^2$). Conclusions: Our results demonstrate that US was the anti-inflammatory effect of chondrocytes. LIPUS may exert its anti inflammatory effects through inhibition of $TNF-{\alpha}$ and IL-1 synthesis. These results suggest that US have potential for use as a pain relief and reduce the articular destruction.

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Chip-scale Temperature-compensated Superstructured Waveguide Bragg Grating Based Multiparametric Sensor

  • Vishwaraj, Naik Parrikar;Nataraj, Chandrika Thondagere;Jagannath, Ravi Prasad Kogravalli;Gurusiddappa, Prashanth;Talabattula, Srinivas
    • Current Optics and Photonics
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    • v.4 no.4
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    • pp.293-301
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    • 2020
  • In this paper we propose and theoretically analyze a monolithic multiparametric sensor consisting of a superstructure of surface-relief waveguide Bragg gratings (WBGs), a micro-machined diaphragm, and a cantilever beam. Diaphragms of two different configurations, namely circular and square, are designed and analyzed separately for pressure measurement. The square diaphragm is then selected for further study, since it shows relatively higher sensitivity compared to the circular one, as it incurs more induced stress when any pressure is applied. The cantilever beam with a proof mass is designed to enhance the sensitivity for acceleration measurement. A unique mathematical method using coupled-mode theory and the transfer-matrix method is developed to design and analyze the shift in the Bragg wavelength of the superstructure configuration of the gratings, due to simultaneously applied pressure and acceleration. The effect of temperature on the wavelength shift is compensated by introducing another Bragg grating in the superstructure configuration. The measured sensitivities for pressure and acceleration are found to be 0.21 pm/Pa and 6.49 nm/g respectively.