• Title/Summary/Keyword: dynamic force

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A Study on the Characters and Costumes in Fantasy Movies - With a Focus on the Mythic Characters - (판타지영화 캐릭터와 의상에 관한 연구 - 신화적 캐릭터를 중심으로 -)

  • Kim, Soo-Kyong;Lee, In-Seung
    • The Research Journal of the Costume Culture
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    • v.18 no.5
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    • pp.1031-1047
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    • 2010
  • This study examines the conceptual characteristics of fantasy movies. It also studies the process of socio-cultural changes of the mythical images such as heroes, goddesses and the devil that have often become the centre of fantasy movie characters. This study further examines the features of each character that correspond to specific mythical images. The purpose of this research is to suggest the conceptual and aesthetic characteristics of fantasy reflected in the characters and the costumes of fantasy movies, which were released since the year 2000. The followings are the results of the research: The conceptual characteristics of fantasy reflected in the characters and the costumes of fantasy movies are summarized as representation of reality, allegory and symbols, horror, desire, deconstruction and metamorphosis, otherness and counter-cultural sentiments. The aesthetic characteristics of the costumes of fantasy movies are defined as typicality and symbolism, grotesqueness, sensuality, hybridization, and otherness. These characteristics are very interconnected. The costumes of heroic characters appearing in fantasy movies show strong side of standard while the costumes of the evil characters revealed the limit of dualistic point of worldview centered on West. Heroic characters show realistic and human side that reflects the ethos of the time. Negative characters such as the devil or witches, which were created in human imagination and emotion, become the dynamic force of fantasy movies through their deviant actions. Their clothes, with variety and hybridization, become the source of creativity expected in present society.

Computational Fluid Dynamic Simulation of Single Bubble Growth under High-Pressure Pool Boiling Conditions

  • Murallidharan, Janani;Giustini, Giovanni;Sato, Yohei;Niceno, Bojan;Badalassi, Vittorio;Walker, Simon P.
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.859-869
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    • 2016
  • Component-scale modeling of boiling is predominantly based on the Eulerian-Eulerian two-fluid approach. Within this framework, wall boiling is accounted for via the Rensselaer Polytechnic Institute (RPI) model and, within this model, the bubble is characterized using three main parameters: departure diameter (D), nucleation site density (N), and departure frequency (f). Typically, the magnitudes of these three parameters are obtained from empirical correlations. However, in recent years, efforts have been directed toward mechanistic modeling of the boiling process. Of the three parameters mentioned above, the departure diameter (D) is least affected by the intrinsic uncertainties of the nucleate boiling process. This feature, along with its prominence within the RPI boiling model, has made it the primary candidate for mechanistic modeling ventures. Mechanistic modeling of D is mostly carried out through solving of force balance equations on the bubble. Forces incorporated in these equations are formulated as functions of the radius of the bubble and have been developed for, and applied to, low-pressure conditions only. Conversely, for high-pressure conditions, no mechanistic information is available regarding the growth rates of bubbles and the forces acting on them. In this study, we use direct numerical simulation coupled with an interface tracking method to simulate bubble growth under high (up to 45 bar) pressure, to obtain the kind of mechanistic information required for an RPI-type approach. In this study, we compare the resulting bubble growth rate curves with predictions made with existing experimental data.

Parametric Study on Reinforced Concrete Columns under Blast Load (주철근의 개수 및 단면비에 따른 폭발하중을 받는 철근콘크리트 기둥의 해석적 연구)

  • Choi, Hosoon;Kim, Min-Sook;Lee, Young-Hak
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.3
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    • pp.219-226
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    • 2012
  • Columns are the key elements supporting load in structure. Column failure causes the structure to collapse. It is important to evaluate residual strength for damaged columns under blast load for preventing progressive collapse. In this paper, columns were investigated to compare the blast resistance on the change of the number of steel bars within the range of reinforcement ratio. And this study was carried out 4 different analytical models to evaluate effects of aspect ratio. The results indicate that the vertical strain was unaffected by the number of steel bars and aspect ratio. As the number of steel bars facing blast load increase, the blast resisting capacity of the columns was improved in the lateral strain. Also, the analysis results showed that a large moment of inertia of area, as compared to a small one would be superior in residual strength as well as force of restitution.

Synthesis of Monodisperse Magnetite Nanocrystallites Using Sonochemical Method (음향화학법을 이용한 균일한 나노 자성체의 합성)

  • Cho, Jun-Hee;Ko, Sang-Gil;Ahn, Yang-Kyu;Song, Ki-Chang;Choi, Eun-Jung
    • Journal of the Korean Magnetics Society
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    • v.16 no.3
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    • pp.163-167
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    • 2006
  • Ultrasonic irradiation in a solution during the chemical reaction may accelerate the rate of the reaction and the crystallization at low temperature. We have synthesized nanometer sized magnetite particles using coprecipitation method, sonochemical method without surfactant, and sonochemical method with surfactant, in order to investigate the effect of ultrasonic irradiation and surfactant on the coprecipitates of metal ions. The size of the magnetite nanoparticles prepared by coprecipitation method, and sonochemical method without surfactant showed broad distributions. But we got uniform nanoparticles using a sonochemical method with oleic acid. The average size of the particles can be controlled by the ratio $R=[H_2O]/[surfactant]$. The size of the magnetite nanoparticles prepared by this method showed narrow distributions. We have characterized the nanoparticles using an X-ray diffraction (XRD), a superconducting quantum interference device (SQUID), and atomic force microscope (AFM). The size and distribution of the magnetite nanoparticles were measured by dynamic light scattering (DLS) method.

Evaluation of Landing Impact Characteristics of Sport Shoes in Running by finite Element Analysis (유한요소 해석을 통한 스포츠화의 런닝 시 착지충격 특성평가)

  • Kim, Sung-Ho;Cho, Jin-Rae;Lee, Shi-Bok;Park, Seung-Bum
    • Korean Journal of Applied Biomechanics
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    • v.19 no.2
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    • pp.217-225
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    • 2009
  • Recently, intensive research efforts are world-widely forced on the development of sport shoes improving both the injury protection and the playing performance by taking kinesiology and biomechanics into consideration. However, the success of this goal depends definitely on the reliable evaluation of the dynamic responses of sport shoes and human foot, particularly the landing impact characteristics. It is because the landing impact force is a main source of unexpected injuries and influences the playing performance in court sport activities. This paper addresses the application of finite element method to the evaluation of landing impact characteristics of barefoot and several representative court sport shoes in running. In order to accurately reflect the coupling effect between human foot and shoes accurately, we construct a fully coupled three-diemensional foot-shoe FEM model which does not rely on the independent experimental data any more. Through the numerical simulation, we assessed the reliability of the numerical FEM model by comparing with the experimental results and investigated the landing impact characteristics, such as GRF, MIF, acceleration and frequency responses, of representative court sport shoes.

Seismic Performance of a Knee-Braced Moment Resisting Frame (Knee brace가 설치된 모멘트저항골조의 내진성능)

  • Choi, Hyun-Hoon;Kim, Jin-Koo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.9 no.1
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    • pp.171-180
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    • 2005
  • In this study the seismic performance of a three-story knee-braced moment-resisting frame (KBMRF), which is typically employed to support pipelines for oil or gas, was investigated. Nonlinear static pushover analyses were performed first to observe the force-displacement relationship of KBMRF under increasing seismic load. The results show that, when the maximum inter-story drift reached 1.5% of the story height, the main structural members, such as beams and columns, still remained elastic. Then nonlinear dynamic time-history analyses were carried out using eight earthquake ground motion time-histories scaled to at the design spectrum of UBC-97. It turned out that the maximum inter-story drift was smaller than the drift limit of 1.5 % of the structure height, and that the columns remained elastic. Based on these analytical results, it can be concluded that the seismic performance of the structure satisfies all the requirements regulated in the seismic code.

Ecological Interface Design for Air Traffic Control Display (항공기 관제 디스플레이의 생태학적 인터페이스 디자인에 관한 연구)

  • Ko, Seung-Moon;Myung, Ro-Hae
    • Journal of the Ergonomics Society of Korea
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    • v.25 no.4
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    • pp.103-113
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    • 2006
  • The purpose of this study was to evaluate an effect of the new air traffic control display designed by Ecological Interface Design [EID]. The methodology of EID has not been applied to the development of the air traffic control display so far. To design a new air traffic control display by EID, We implemented Work Domain Analysis about the air traffic control domain and made the Work Domain Model that consisted of the five levels of the Abstraction Hierarchy. We extracted the Information Requirement from the completed Work Domain Model and the extracted information requirements from the model were used to design the new air traffic control display. We evaluated an effect of the new air traffic control display designed by EID. Participants for evaluating consisted of 14 active military air traffic controller of the Republic of Korea Air Force. Experiment was designed two factors within subject. Factors manipulated in the experiment included displays type to compare the existing type with the new ecological interface type and included complexity to compare the effect of the high complex situation with the effect of the low complex situation. Response time about questions with relation to air traffic collision situation, accuracy, and subjective work load were measured. The results reveled that EID type's display has a significant effect on response time, accuracy, and subjective work load and verified that EID could be applied to the air traffic control domain that is more complex and dynamic.

Real-time model updating for magnetorheological damper identification: an experimental study

  • Song, Wei;Hayati, Saeid;Zhou, Shanglian
    • Smart Structures and Systems
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    • v.20 no.5
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    • pp.619-636
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    • 2017
  • Magnetorheological (MR) damper is a type of controllable device widely used in vibration mitigation. This device is highly nonlinear, and exhibits strongly hysteretic behavior that is dependent on both the motion imposed on the device and the strength of the surrounding electromagnetic field. An accurate model for understanding and predicting the nonlinear damping force of the MR damper is crucial for its control applications. The MR damper models are often identified off-line by conducting regression analysis using data collected under constant voltage. In this study, a MR damper model is integrated with a model for the power supply unit (PSU) to consider the dynamic behavior of the PSU, and then a real-time nonlinear model updating technique is proposed to accurately identify this integrated MR damper model with the efficiency that cannot be offered by off-line methods. The unscented Kalman filter is implemented as the updating algorithm on a cyber-physical model updating platform. Using this platform, the experimental study is conducted to identify MR damper models in real-time, under in-service conditions with time-varying current levels. For comparison purposes, both off-line and real-time updating methods are applied in the experimental study. The results demonstrate that all the updated models can provide good identification accuracy, but the error comparison shows the real-time updated models yield smaller relative errors than the off-line updated model. In addition, the real-time state estimates obtained during the model updating can be used as feedback for potential nonlinear control design for MR dampers.

Experimental dynamic performance of an Aluminium-MRE shallow shell

  • Zhang, Jiawei;Yildirim, Tanju;Neupane, Guru Prakash;Tao, Yuechuan;Bingnong, Jiang;Li, Weihua
    • Smart Structures and Systems
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    • v.25 no.1
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    • pp.57-64
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    • 2020
  • The nonlinear dynamics of a directly forced clamped-clamped-free-free magneto-rheological elastomer (MRE) sandwich shell has been experimentally investigated. Experiments have been conducted on an aluminium shallow shell (shell A) and an MRE-aluminium sandwich shallow shell with single curvature (shell B). An electrodynamic shaker has been used to directly force shells A and B in the vicinity of their fundamental resonance frequency; a laser displacement sensor has been used to measure the vibration amplitude to construct the frequency-response curves. It was observed that for an aluminium shell (shell A), that at small forcing amplitudes, a weak softening-type nonlinear behaviour was observed, however, at higher forcing amplitudes the nonlinear dynamical behaviour shifted and a strong hardening-type response occurred. For the MRE shell (shell B), the effect of forcing amplitude showed softening at low magnetic fields and hardening for medium magnetic fields; it was also observed the mono-curved MRE sandwich shell changed dynamics to quasiperiodic displacement at some frequencies, from a periodic displacement. The presence of a magnetic field, initial curvature, and forcing amplitude has significant qualitative and quantitative effects on the nonlinear dynamical response of a mono curved MRE sandwich shell.

Numerical study of wake and aerodynamic forces on a twin-box bridge deck with different gap ratios

  • Shang, Jingmiao;Zhou, Qiang;Liao, Haili;Larsen, Allan;Wang, Jin;Li, Mingshui
    • Wind and Structures
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    • v.30 no.4
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    • pp.367-378
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    • 2020
  • Two-dimensional Delayed Detached Eddy Simulation (DDES) was carried out to investigate the uniform flow over a twin-box bridge deck (TBBD) with various gap ratios of L/C=5.1%, 12.8%, 25.6%, 38.5%, 73.3% and 108.2% (L: the gap-width between two girders, C: the chord length of a single girder) at Reynolds number, Re=4×104. The aerodynamic coefficients of the prototype deck with gap ratio of 73.3% obtained from the present simulation were compared with the previous experimental and numerical data for different attack angles to validate the present numerical method. Particular attention is devoted to the fluctuating pressure distribution and forces, shear layer reattachment position, wake velocity and flow pattern in order to understand the effects of gap ratio on dynamic flow interaction with the twin-box bridge deck. The flow structure is sensitive to the gap, thus a change in L/C thus leads to single-side shedding regime at L/C≤25.6%, and co-shedding regime at L/C≥35.8% distinguished by drastic changes in flow structure and vortex shedding. The gap-ratio-dependent Strouhal number gradually increases from 0.12 to 0.27, though the domain frequencies of vortices shedding from two girders are identical. The mean and fluctuating pressure distributions is significantly influenced by the flow pattern, and thus the fluctuating lift force on two girders increases or decreases with increasing of L/C in the single-side shedding and co-shedding regime, respectively. In addition, the flow mechanisms for the variation in aerodynamic performance with respect to gap ratios are discussed in detail.