• Advances in aircraft and spacecraft science
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• 제4권6호
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• pp.711-727
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• 2017

This article is concerned with a two-dimensional problem of micropolar generalized thermoelasticity for a half-space whose surface is traction-free and the conductive temperature at the surface of the half-space is known. Theory of two-temperature generalized thermoelasticity with phase lags using the normal mode analysis is used to solve the present problem. The formulas of conductive and mechanical temperatures, displacement, micro-rotation, stresses and couple stresses are obtained. The considered quantities are illustrated graphically and their behaviors are discussed with suitable comparisons. The present results are compared with those obtained according to one temperature theory. It is concluded that both conductive heat wave and thermodynamical heat wave should be separated. The two-temperature theory describes the behavior of particles of elastic body more real than one-temperature theory.

• 한국전산유체공학회지
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• 제13권1호
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• pp.28-34
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• 2008

A particle method recognized as one of the gridless methods has been developed to investigate the nonlinear free-surface motions interacting to the structures. The method is more feasible and effective than convectional grid methods for solving the non-linear free-surface motion with complicated boundary shapes. The right-handed side of the governing equations for incompressible fluid, which includes gradient, viscous and external force terms, can be replaced by the particle interaction models. In the present study, the developed method is applied to the dam-broken problem on dried- and wet-floor and its adequacy will be discussed by the comparison with the experimental results.

• Journal of electromagnetic engineering and science
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• 제13권1호
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• pp.16-21
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• 2013

This study presents the angular effects of virtual vertices inserted for effective treatment of the boundary edge laid on an infinite conducting surface in a half-space scattering problem. We investigated the angular effects of virtual vertices by first computing the radar cross section (RCS) of a specific scatterer; i.e., a tilted conducting plate in contact with the ground surface, by inserting the virtual vertex in half-space. Here, the electric field integral equation is used to solve this problem with various virtual vertex angles (${\theta}_{\nu}$) and conducting plate inclination angles (${\theta}_r$) ranging from $0^{\circ}$ to $180^{\circ}$. The effects of the angles ${\theta}_{\nu}$ and ${\theta}_r$ on the RCS computation are clearly shown with numerical results with and without the virtual vertices in free- and half-spaces.

• 전기학회논문지
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• 제67권7호
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• pp.865-870
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• 2018

A machine vision based industrial inspection includes defects detection and classification. Fast inspection is a fundamental problem for many applications of real-time vision systems. It requires little computation time and localizing defects robustly with high accuracy. Deep learning technique have been known not to be suitable for real-time applications. Recently a couple of fast region-based CNN algorithms for object detection are introduced, such as Faster R-CNN, and YOLOv2. We apply these methods for an industrial inspection problem. Three CNN based detection algorithms, VOV based CNN, Faster R-CNN, and YOLOv2, are experimented for defect detection on metal surface. The results for inspection time and various performance indices are compared and analysed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.258-263
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• 2007

A particle method recognized as one of the gridless methods has been developed to investigate the nonlinear free-surface motions interacting to the structures. The method is more feasible and effective than convectional grid methods for solving the non-linear free-surface motion with complicated boundary shapes. The right-handed side of the governing equations for incompressible fluid, which includes gradient, viscous and external force terms, can be replaced by the particle interaction models. In the present study, the developed method is applied to the dam-broken problem on dried- and wet-floor and its adequacy will be discussed by the comparison with the experimental results.

• 대한조선학회논문집
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• 제47권1호
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• pp.1-10
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• 2010

In the present paper, a numerical method based on the constraint interpolation profile (CIP) method is applied for simulating two-dimensional violent sloshing problems. The free surface boundary value problem is considered as a multiphase problem which includes water and air. A stationary Cartesian grid system is adopted, and an interface capturing method is used to trace the shape of free surface profile. The CIP combined unified procedure (CCUP) scheme is applied for flow solver, and the tangent of hyperbola for interface capturing (THINC) scheme is used for interface capturing. Numerical simulations have been carried out for partially-filled 2D tanks under forced sway and roll motions at various filling depths and frequencies. The computational results are compared with experiments and/or the other numerical results to validate the present numerical method.

• Tribology and Lubricants
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• 제24권2호
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• pp.90-95
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• 2008

An elastic-plastic contact analysis is developed using a semi-analytical method. The elastic contact is solved within a Hertz theorem. The reciprocal theorem with initial strains is then introduced, to express the surface geometry as a function of contact stress and plastic strains. The irreversible nature of plasticity leads to an incremental formulation of the elastic-plastic contact problem, and an algorithm to solve this problem is set up. Closed form expression, which give residual stresses and surface displacements from plastic strains, are obtained by integration of the reciprocal theorem. The distribution of contact stress, residual stress and plastic strain are obtained by the changed surface geometry.

• 센서학회지
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• 제21권5호
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• pp.374-378
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• 2012

Biofouling causes many problem in industrial processes, medical health industries, water utilities and our daily life. So detecting formation of biofilm on the surface of medical appliance, water pipe and industrial utility is highly important to prevent the problem caused by biofouling. In this study, we suggest an electrochemical sensor for detecting biofilm. We fabricated the electrochemical sensor in MEMS process and cultivated two different kinds of Pseudomonas aeruginosa RpoN type and Wild type on the surface of electrochemical sensor. Each group of Pseudomonas aeruginosa was cultivated according to the hours of 2, 4, 6, 8, 12 and 24. Then we investigated changes in degree of biofilm cultivation using cyclic voltammetry. As a result, it was observed that peak of the cyclic voltammetry curve is increased according as the biofilm growth on the surface of electrochemical sensor. Also we can discern between Pseudomonas aeruginosa RpoN type and Wild type.

• 대한조선학회지
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• 제25권2호
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• pp.11-18
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• 1988

The radiation problem for an oscillating cylinder advancing under the free surface with a constant horizontal velocity is studied using the Green integral equation in the frequency domain. The Green function expressed in terms of the complex exponential, is derived using the damped free surface condition. Special attention is given to the behavior of the numerical solution in the vicinity of the critical Brard number ${\gamma}_c=\omega{\cdot}u/g=0.25$ where $\omega$ is the circular frequency of encounter, u the advancing speed and g the gravitational acceleration. It is shown that the solution is finite in the vicinity of ${\gamma}_c$ although the Green function becomes singular at ${\gamma}_c$. It is also shown that the computed hydrodynamic coefficients agree well with those obtained from the solution of the same problem formulated in the time domain.

• 자원리싸이클링
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• 제12권2호
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• pp.28-35
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• 2003

폐타이어의 처리방법으로서는 recycling이 가장 최선의 방법 중의 하나이다. 하지만 재활용의 어려움 중에는 경제성의 문제가 있다. 이러한 문제점을 해결하기 위해서는 폐타이어의 입자 크기를 줄이는 방법과 표면처리를 통하여 제품의 물성을 향상시키는 방법이 있다. 본 연구에서는 두 방법을 동시에 응용한 방법으로 폐타이어의 입자크기를 작게 하고 ultrasonic 처리를 하였다. 그 결과로 폐타이어 가황 시스템의 변화를 가져옴으로서 물성의 향상을 알 수 있었다. 이러한 기술은 재활용의 경제성을 높이는 기초기술임을 알 수 있었다.