• Title/Summary/Keyword: Tool Stress

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Temperature Effect on Ultrasonic Stress Wave Velocity of Wood (목재 초음파 전달속도에 대한 온도의 영향)

  • Kang, Ho-Yang
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.1
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    • pp.50-55
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    • 1999
  • Since ultrasonic stress wave velocity varies with wood temperature and moisture content, ultrasonic stress wave could be a tool to predict wood moisture content if temperature effect could be eliminated. This temperature effect was investigated by measuring the velocities of ultrasonic stress waves transmitting through air, a metal bar and a dimension lumber at various temperatures. For air the velocity and amplitude of the ultrasonic stress wave increase with temperature, while for a metal bar and a dimension lumber those decrease as temperature increases. However all three materials showed velocity hystereses with a temperature cycle. The effect of temperature and moisture content on stress wave velocity of a dimension lumber was depicted in the form of a three dimensional graph. The plot of stress wave velocity vs. wood moisture content was well fitted by two regression equations: a exponential equation below 46% and a linear equation above 46%.

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Comparison of assessment by OCRA Checklist and RULA at an auto Manufacturing Plant (자동차 산업에서의 OCRA Checklist와 RULA 평가 비교)

  • Lee, Kwan-Suk;Jung, Min-Soo;Jeon, Seong-Jae;Chun, Young-Ji;Kim, Jae-Hyoung
    • Journal of the Ergonomics Society of Korea
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    • v.26 no.4
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    • pp.153-160
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    • 2007
  • Due to the high occurrence rate of musculoskeletal disorders(MSDs), many Korean companies adopted various assessment tools to evaluate workers' musculoskeletal stress. Using the results of this evaluation, tasks were selected for improvements. However, there are still many workers who complained of musculoskeletal stress of their tasks. Their tasks usually consist of repetitive activities and a short rest cycle. This prompts a concern of reliability of the evaluation tools and especially RULA. Thus in this study, OCRA(The Occupational Repetitive Action tool) was used to check whether RULA(Rapid Upper Limb Assessment) evaluates workers' musculoskeletal stress reasonably well since OCRA has been known to be a good evaluation tool for repetitive tasks and tasks with short recovery periods. The evaluation was conducted on 142 tasks. It was found that 65 tasks showed higher action levels by OCRA than by RULA. However, 13 tasks showed the reversed result and 64 tasks showed the same level regardless of the evaluation tool. It was concluded that either RULA or OCRA alone cannot evaluate all types of tasks very well. It is suggested that OCRA needs to be used with RULA together for the evaluations of musculoskeletal stress at workplaces where repetitive activities and short recovery periods exist.

How to measure fashion stress? Development and validation of a multidimensional scale for fashion stress (패션 스트레스는 어떻게 측정할 수 있는가? 패션 스트레스의 다차원 척도 개발 및 타당화)

  • Hyojung Suk;Eun-Jin Lee
    • The Research Journal of the Costume Culture
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    • v.32 no.2
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    • pp.181-198
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    • 2024
  • Fashion stress is a pertinent aspect of modern consumer culture that has been underexplored in academic research. This study developed a conceptual framework of fashion stress and a multidimensional scale to measure consumers' fashion stress. The qualitative study included literature reviews on consumption stress, shopping stress, and consumer behavior, as well as focus group interviews to gain insight into various dimensions of fashion stress. NVivo 12.0 was used to analyze the qualitative data and identify core categories following the grounded theory methodology. The quantitative study involved a preliminary and a primary surveys to verify the validity and reliability of the fashion stress scale. A total of 220 questionnaires were used for data analysis. The results show that fashion stress consists of eight factors: care, shopping, fit, brand, financial, closet, style, and disposal. Choice difficulty plays a significant role in all factors of fashion stress. Moreover, shopping stress had a negative impact on impulse buying, while other factors such as fit, brand, closet, and disposal stress had a positive impact on impulse buying. Thus, fashion stress is a potential antecedent of impulsive consumer behavior. The results also confirm the validity and reliability of the scale. The fashion stress scale developed in this study offers researchers a valuable tool for assessing and understanding consumer experiences.

A Study on the Residual Stress Distribution of Pure Titanium Welding Material (순수티타늄 용접재의 잔류응력분포에 관한 연구)

  • 최병기;권택용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.70-75
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    • 2002
  • It is generally applied constraint welding condition to structure manufacture in the industry field. But it is thinkable that the residual stress of the construction and specimens for experiment is different because not constraint welding but non-constraint welding are applied for experiment. To apply the constraint welding condition as the industry field and compare and evaluate the welding residual stress distribution, the TlG welding of the pure titanium was carried out under constraint and non-constraint welding conditions

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On the Springback Analysis of Sheet Metal Forming (판재성형의 탄성복원해석에 대하여)

  • 조진우;정완진
    • Transactions of Materials Processing
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    • v.6 no.5
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    • pp.386-394
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    • 1997
  • The analysis of the springback is done based on the stress of sheet after forming. Therfore, it is important to get the accurate stress from forming analysis. In this study, some parameters that influence on the accuracy of the springback estimation are investigated. Discretization of sheet and tools, choice of penalty constant and damping in contact treatment, and tool speed scaling are chosen as parameters. As a numerical example, the 2D draw bending benchmark problem of the NUMISHEET'93 is used. Also, the springback results of the s-rail benchmark problem of the NUMISHEET'96 are presented.

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Crack Propagation Behavior for Variable Load in Cantilever Beam under Bending Load (굽힘하중의 받는 외팔보의 변동하중에 대한 균열진전 거동)

  • 김엽래
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.03a
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    • pp.178-183
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    • 1998
  • This paper examines the crack growth behavior of 7075-T651 and 5052-H32 aluminum alloys for variable load within tensile load range condition. The cantilever beam type specimen with a chevron notch is used in this study. The crack growth and closure are investgated by compliance method. The applied initial stress ratio is R=0.3 and variable load are R=0.65, 0.46. Crack length, stress intensity factor range, ratio of effective stress intensity factor range and crack growth rate etc. are inspected with fracture mechanics estimate.

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A Study on the strength improvement in weldment by the impact loading (충격하중에 의한 용접구조물의 강도 증가에 관한 연구)

  • 이천수
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.10a
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    • pp.121-124
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    • 1998
  • It is well known that during the oxygen cutting residual thermal stresses are produced in weldment. Surface compressive residual stress is one of reasons for improvement on fatigue durability. To reduce the residual stress and improve the fatigue strength applied the impact loading in oxygen cutting frame. After applying the impact loading, redistribution of residual stress was measured by cutting method and tested fatigue tests.

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Plastic Design Method for Moment Resisting Frame based on Designer's Acceptable Matrix (설계자 만족도 매트릭스를 이용한 골조 구조물의 소성해석법)

  • Song, Ki-Young;Lee, Seung-Jae;Oh, Sang-Hoon;Kang, Chang-Hoon
    • Proceeding of KASS Symposium
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    • 2006.05a
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    • pp.165-169
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    • 2006
  • This study presents a new stress analysis method to be substituted for the elastic analysis in such a plastic design procedure. This method is accompanied by an efficient mathematical tool which can be easily handled by personal computer. The method also easily accepts arbitrary strategies by the designer for selection member size.

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Comparative Analysis of Work Stress Assessment Tools for Estimating Human Work Performance (업무수행도 추정을 위한 직무스트레스 평가표의 비교 분석)

  • Jang, Tong-Il;Lee, Yong-Hee;Han, Kyu-Jeong;Lim, Hyeon-Kyo
    • Journal of the Korean Society of Safety
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    • v.29 no.6
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    • pp.144-150
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    • 2014
  • A man is a component of a large system how complex it may be so that human performance which can influence on the system safety should be included in system safety assessment. Meanwhile, human performance can vary over time due to lots of factors. Among them, stress is an indirect factor that may cause human error which can result in industrial accidents. To assess stress level of human workers, not a few assessment tools have been developed. However, it can be questionable to utilize them for human performance anticipation because they were mainly developed with the viewpoint of mental health, though stress assessment can be also required in the safety aspect. Therefore, this study aimed to survey the possibility of their application with safety purpose. About 10 kinds of work stress tools were collected and analyzed with reference to assessment items, assessment and analysis methods, and follow-up measures. The results showed that most tools focused their weights on Demands, Supports, and Relationships, in sequence. However, they, except only one tool developed by the Japanese researchers, merely advised to set up counterplans in PDCA cycle or risk management activities. In consequence, application of stress assessment tools mainly developed for mental health seemed impractical for safety purpose with respect to human performance anticipation so that it was concluded that development of a new assessment tools aimed to human performance variation and accident prevention would be inevitable.

The Effect of Care Giver's Knowledge and Attitude toward the Elderly on Job Stress (요양보호사의 노인에 대한 지식 및 태도가 직무스트레스에 미치는 영향)

  • Chon, Kang-Nan;Park, Ok-Im;Moon, Hee
    • The Korean Journal of Community Living Science
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    • v.21 no.1
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    • pp.19-32
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    • 2010
  • The purpose of this study was to identify the level of care-givers' knowledge, their attitude towards the elderly and their stress levels within the job, and to apprehend the cause which has had an influence on job stress. The research subjects were 230 care-givers who work in a sanitarium for the elderly in the East of Jeollanamdo. The tool used to measure their knowledge of the elderly was FAQ1 and the semantic differential scale was used to determine the attitude. Job stress was measured by the tool which was used by sun-ju Park. The data analysis was carried out by SPSS Win 13.0. The results of this study are as follows; The care-givers' knowledge level point towards the elderly was relatively low at 44.6%. The average point of attitude toward the elderly was 3.91, which is relatively moderate. The percentages of job stress was generally low. The results showed us that there was no correlation with the knowledge level of the elderly, the attitude towards the elderly and job stress. Since the results indicated that care-givers' knowledge level for the elderly was low, we reached the conclusion that further education where care-givers can get general knowledge for the elderly and aging is necessary. Moreover, research for strengthening positive attitudes towards the elderly is also necessary.