• Title/Summary/Keyword: Sources of stress

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Ergonomic Job Hazard Assessment of Hotel Chef (호텔 요리사의 인간공학적 작업 위험성 평가)

  • Ahn, Tae-Hoon;Kim, Jun-Sik;Jeong, Byung-Yong
    • Journal of the Ergonomics Society of Korea
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    • v.25 no.3
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    • pp.105-111
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    • 2006
  • This paper summarizes the ergonomic risk assessment of hotel chef. The cooking operations were observed in order to determine sources of ergonomic stress and make recommendations to reduce the risk of work-related musculoskeletal disorders in Korean, Japanese, and western style cooking. We used interviews, document analysis, video analysis, and risk assessment to identify and quantify ergonomic risk factors. The results indicate that the cooking operations have some ergonomic problems. These findings identified in this study can be used to reduce the risk of work-related musculoskeletal disorders in food service areas.

Advanced analysis for planar steel frames with semi-rigid connections using plastic-zone method

  • Nguyen, Phu-Cuong;Kim, Seung-Eock
    • Steel and Composite Structures
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    • v.21 no.5
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    • pp.1121-1144
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    • 2016
  • This paper presents a displacement-based finite element procedure for second-order distributed plasticity analysis of planar steel frames with semi-rigid beam-to-column connections under static loadings. A partially strain-hardening elastic-plastic beam-column element, which directly takes into account geometric nonlinearity, gradual yielding of material, and flexibility of semi-rigid connections, is proposed. The second-order effects and distributed plasticity are considered by dividing the member into several sub-elements and meshing the cross-section into several fibers. A new nonlinear solution procedure based on the combination of the Newton-Raphson equilibrium iterative algorithm and the constant work method for adjusting the incremental load factor is proposed for solving nonlinear equilibrium equations. The nonlinear inelastic behavior predicted by the proposed program compares well with previous studies. Coupling effects of three primary sources of nonlinearity, geometric imperfections, and residual stress are investigated and discussed in this paper.

Airbag Accelerometers Using Silicon Epitaxial Layers (실리콘 에피층을 이용한 자동차 에어백용 가속도계)

  • 고종수;김규현;이창렬;조영호;이귀로;곽병만
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.5
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    • pp.9-15
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    • 1996
  • A silicon microaccelerometer is designed and fabricated using silicon epitaxial layers for automotive electronic airbag applications. A cantilever structure is chosen for high sensitivity and piezoresistive detection method is adopted for circuit simplicity and low cost. An optimum design is used to find optimum microstructure sizes for maximum sensitivity subject to performance requirements and design constraints on natural frequency, damping ratio, maximum allowable stress and microfabrication limitations. The microaccelerometer is fabricated by micromachining processing steps, composed of material-selective and orientation-dependent chemical etching techniques. Fabricated prototype shows a sensitivity of 88.6$\mu\textrm{V}$/g within a resonant frequency of 1.75KHz. Estimated performance of the microaccelerometer is compared with measured one. Discrepancy between the theoretical values and the experimental values is discussed together with possible sources of the errors.

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Verification on Damage Calculating Method of Vibration Fatigue Using Uni-axial Vibration Test (단축가진 시험을 통한 진동내구 손상도 계산)

  • Kim, Chan-Jung;Bae, Chul-Yong;Lee, Bong-Hyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.5 s.110
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    • pp.521-528
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    • 2006
  • The vibration fatigue is suitable case of fatigue problem that system is exposed to the random or other irregular sources. Even some kinds of effort using power spectral density (PSD) and statistical concept was presented to cope with the intangible force signal, it is still lack of providing a reasonable solution when its exciting frequency is near or beyond of first eigenvalue. In this paper, energy approach method is presented to calculate a vibration induced fatigue damage in frequency domain. Since the corresponding damage become much larger than nominal case when the vibration is coupled with a mode shape of given structure, the new technique compensate the characteristics of structure with a measured frequency response function (FRF) between forcing acceleration and responding stress.

A Study on the thermal behaviors of a machine tool with linear motors (리니어 모터를 적응한 공작기계의 열변형 특성에 관한 연구)

  • 김종진;조동우
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.36-40
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    • 2002
  • The development of feed drive system with high speed and accuracy has been a major issue in the machine tool industry. Linear motors can be used as the efficient tool to achieve fast feed mechanism and high accuracy. However. a high speed feed drive system with linear motors can generate heat problems such as the variation of temperature distribution and the resultant thermal stress. In this paper, the important heat sources and the resultant thermal errors are presented. The thermal deformation characteristics of the machine tool with linear motors were identified, which are thermal expansion of linear scale, shrinkage, expansion and bending in the machine tool structure.

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Effect of nonlocal parameter on nonlocal thermoelastic solid due to inclined load

  • Lata, Parveen;Singh, Sukhveer
    • Steel and Composite Structures
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    • v.33 no.1
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    • pp.123-131
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    • 2019
  • The present investigation is concerned with two dimensional deformation in a homogeneous nonlocal thermoelastic solid with two temperature. The nonlocal thermoelastic solid is subjected to inclined load. Laplace and Fourier transforms are used to solve the problem. The bounding surface is subjected to concentrated and distributed sources. The analytical expressions of displacement, stress components, temperature change are obtained in the transformed domain. Numerical inversion technique has been applied to obtain the results in the physical domain. Numerical simulated results are depicted graphically to show the effect of angle of inclination and nonlocal parameter on the components of displacements, stresses and conductive temperature. Some special cases are also deduced from the present investigation.

Effect of two-temperature in an orthotropic thermoelastic media with fractional order heat transfer

  • Lata, Parveen;Himanshi, Himanshi
    • Composite Materials and Engineering
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    • v.3 no.3
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    • pp.241-262
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    • 2021
  • In this article, we studied the effect of two-temperature in a two-dimensional orthotropic thermoelastic media with fractional order heat transfer in generalized thermoelasticity with three-phase-lags due to thermomechanical sources. The boundary of the surface is subjected to linearly distributed and concentrated loads (mechanical and thermal source). The solution of the problem is obtained with the help of Laplace and Fourier transform techniques. The expressions for displacement components, stress components and conductive temperature are derived in transformed domain. Numerical inversion technique is used to obtain the results in physical domain. The effect of two-temperature on all the physical quantities has been depicted with the help graphs. Some special cases are also discussed in the present investigation.

Development of functional substances on Alzheimer's disease

  • Heo, Ho-Jin
    • Food preservation and processing industry
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    • v.6 no.2
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    • pp.25-29
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    • 2007
  • Phytochemicals have long been known to hold a number of physiological benefits, including antioxidant, anticardiovascular activities and anticancer. The profitable effects of phytochemicals from food sources such as vegetables and fruits, with respect to neurodegeneration, are only beginning to receive increased attention. Alzheimer's disease(AD) is one of the major neurodegenerative diseases for which no treatment is available, and characterized by loss of cognitiion and memory. Many recent studies show that the brain of AD patient is subjected to increased oxidative stress resulting from free radical damage, and the resulting cellular malfunctions are widely believed to be responsible for neuronal degeneration in AD. In this study, the relative relation between D and phytochemicals were surveyed.

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Axisymmetric thermomechanical analysis of transversely isotropic magneto thermoelastic solid due to time-harmonic sources

  • Lata, Parveen;Kaur, Iqbal
    • Coupled systems mechanics
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    • v.8 no.5
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    • pp.415-437
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    • 2019
  • The present research deals with two-dimensional axisymmetric deformation in transversely isotropic magneto thermoelastic solid with and without energy dissipation, with two temperature and time-harmonic source. The proposed model is helpful for finding the type of relations between mechanical and thermal fields as most of the structural elements of heavy industries are frequently related to mechanical and thermal stresses at a higher temperature. The Hankel transform has been used to find a solution to the problem. The displacement components, stress components, and temperature distribution with the horizontal distance in the physical domain are calculated numerically. The effect of time-harmonic source and two temperature is depicted graphically on the resulting quantities.

Orthotropic magneto-thermoelastic solid with multi-dual-phase-lag model and hall current

  • Lata, Parveen;Himanshi, Himanshi
    • Coupled systems mechanics
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    • v.10 no.2
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    • pp.103-121
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    • 2021
  • The present research deals with the investigation of the effect of hall current in an orthotropic magneto-thermoelastic medium with two temperature in the context of multi-phase-lag heat transfer due to thermomechanical sources. The bounding surface is subjected to linearly distributed and concentrated loads(mechanical and thermal source).Laplace and Fourier transform techniques are used to solve the problem. The expressions for displacement components,stress components and conductive temperature are derived in transformed domain and furtherin physical domain with the help of numerical inversion techniques. The effect ofrotation and hall parameter hasshown with the help of graphs.