• 제목/요약/키워드: visualization materials

검색결과 280건 처리시간 0.022초

얕은 직사각형 통내의 혼돈적 교반 (The Chaotic Stirring in a Shallow Rectangular Tank)

  • 서용권;문종춘
    • 대한기계학회논문집
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    • 제18권2호
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    • pp.380-388
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    • 1994
  • Study on the chaotic stirring has been performed numerically and experimentally for a shallow rectangular tank accompanying a vortex shedding. The model is composed of a rectangular tank with a vertical plate with a length half the width of the tank. The tank is subject to a horizontal sinusoidal oscillation. The chaotic stirring was analysed by Poincare sections, unstable manifolds and Lyapunov exponents. As Reynolds number is increased the stirring effect is decreased due to the growth of a regular regions near the lower surface of the tank. In the other hand decrease of Reynolds number gives a weaker vortex shedding resulting in the poorer stirring effect. It was also found that the Lyapunov exponent is the highest at the dimensionless period of 1.3-1.5, which seems to be the best condition for the efficient stirring. The experimental visualization for the deformation of materials exhibits the striation pattern similar to the unstable manifold obtained numerically.

압전 액츄에이터를 이용한 열전냉각 시스템 성능 향상에 관한 연구 (A Study on Enhancement of Thermoelectric Cooling System Performance by Piezoelectric Actuator)

  • 양호동;윤희성;오율권
    • 한국안전학회지
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    • 제24권6호
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    • pp.13-19
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    • 2009
  • The thermoelectric cooling system consisted of the thermoelectric module, a heat sink and a cooling fan, respectively. Also, the piezoelectric actuator was applied to improve the performance of thermoelectric cooling system and investigate the heat transfer phenomenon. The temperature distribution of test section was measured to investigate cooling characteristics of thermoelectric cooling system. The flow phenomenon of test section was visualized using visualization device. When the piezoelectric actuator was applied to the heat transfer process of thermoelectric cooling system, acoustic streaming was occurred in test section. The acoustic streaming was occurred forced convection flow, and was regularly formed the temperature distribution in test section. The results clearly show that the acoustic streaming is one of the prime effects to enhance the convection heat transfer and can enhance the performance of thermoelectric cooling system.

Measuring high speed crack propagation in concrete fracture test using mechanoluminescent material

  • Kim, Wha-Jung;Lee, Jae-Min;Kim, Ji-Sik;Lee, Chang Joon
    • Smart Structures and Systems
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    • 제10권6호
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    • pp.547-555
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    • 2012
  • Measuring crack length in concrete fracture test is not a trivial problem due to high speed crack propagation. In this study, mechanoluminascent (ML) material, which emits visible light under stress condition, was employed to visualize crack propagation during concrete fracture test. Three-point bending test was conducted with a notched concrete beam specimen. The cracking images due to ML phenomenon were recorded by using a high speed camera as a function of time and external loadings. The experimental results successfully demonstrated the capability of ML material as a promising visualization tool for concrete crack propagation. In addition, an interesting cracking behavior of concrete bending fracture was observed in which the crack propagated fast while the load decreased slowly at early fracture stage.

Classification and visualization of primary trabecular bone in lumbar vertebrae

  • Basaruddin, Khairul Salleh;Omori, Junya;Takano, Naoki;Nakano, Takayoshi
    • Advances in biomechanics and applications
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    • 제1권2호
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    • pp.111-126
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    • 2014
  • The microarchitecture of trabecular bone plays a significant role in mechanical strength due to its load-bearing capability. However, the complexity of trabecular microarchitecture hinders the evaluation of its morphological characteristics. We therefore propose a new classification method based on static multiscale theory and dynamic finite element method (FEM) analysis to visualize a three-dimensional (3D) trabecular network for investigating the influence of trabecular microarchitecture on load-bearing capability. This method is applied to human vertebral trabecular bone images obtained by micro-computed tomography (micro-CT) through which primary trabecular bone is successfully visualized and extracted from a highly complicated microarchitecture. The morphological features were then analyzed by viewing the percolation of load pathways in the primary trabecular bone by using the stress wave propagation method analyzed under impact loading. We demonstrate that the present method is effective for describing the morphology of trabecular bone and has the potential for morphometric measurement applications.

X-ray Micro-Imaging 기법 소개 및 불투명 튜브 내부의 마이크로 버블 가시화 연구 (X-ray Micro-Imaging Technique and Its Application to Micro-Bubbles in an Opaque Tube)

  • 이상준;김석;백부근
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2002년도 추계학술대회 논문집
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    • pp.31-34
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    • 2002
  • Imaging techniques using x-ray beam at high energies (>6KeV) such as contact radiography, projection microscopy, and tomography have been used to nondestructively discern internal structure of objects in material science, biology, and medicine. This paper introduces the x-ray micro-imaging method using 1B2 micro-probe line of PAL (Pohang Accelerator Laboratory). Cross-sectional information on low electron density materials can be obtained by probing a sample with coherent synchrotron x-ray beam in an in-line holography setup. Living organism such as plants, insects are practically transparent to high energy x-rays and create phase shift images of x-ray wave front. X-ray micro-images of micro-bubbles of $20\~120\;{\mu}m$ diameter in an opaque tube were recorded. Clear phase contrast images were obtained at Interfaces between bubbles and surrounding liquid due to different decrements of refractive index.

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창호의 개폐조절을 기반으로 한 리스펀시브 뉴메틱 파사드 (Responsive Pneumatic Facade with Adaptive Openings for Natural Ventilation)

  • 이지선;이현수
    • 대한건축학회논문집:계획계
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    • 제33권12호
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    • pp.29-39
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    • 2017
  • The building skins are important architectural elements in both functional and aesthetical aspects. This study focuses on developing a responsive facade with autonomous opening and closing behaviors in accordance with environmental conditions and user requirements for natural ventilation for the office building. The pneumatic ETFE panels are applied as the skin materials taking advantage of the efficiency of the inflatable skin of lightness, architectural performance and sustainable material properties. The biomimetic design methodology is taken for its innovative and visionary concept for the facade design. The interpretation of the building facade in analogy to natural organisms delivers functional and aesthetic characters. By exploring the structural movements of the plant pores, the facade control is developed to be autonomous by the parameter values. The facade opening and closing configurations are derived through parametric modeling and visualization programming. Through the application of this study, expected results are to improve user comfort and energy efficiency.

Rearch of Late Adolcent Activity based on Using Big Data Analysis

  • Hye-Sun, Lee
    • International Journal of Advanced Culture Technology
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    • 제10권4호
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    • pp.361-368
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    • 2022
  • This study seeks to determine the research trend of late adolescents by utilizing big data. Also, seek for research trends related to activity participation, treatment, and mediation to provide academic implications. For this process, gathered 1.000 academic papers and used TF-IDF analysis method, and the topic modeling based on co-occurrence word network analysis method LDA (Latent Dirichlet Allocation) to analyze. In conclusion this study conducted analysis of activity participation, treatment, and mediation of late adolescents by TF-IDF analysis method, co-occurrence word network analysis method, and topic modeling analysis based on LDA(Latent Dirichlet Allocation). The results were proposed through visualization, and carries significance as this study analyzed activity, treatment, mediation factors of late adolescents, and provides new analysis methods to figure out the basic materials of activity participation trends, treatment, and mediation of late adolescents.

Software development for the visualization of brain fiber tract by using 24-bit color coding in diffusion tensor image

  • Oh, Jung-Su;Song, In-Chan;Ik hwan Cho;Kim, Jong-Hyo;Chang, Kee-Hyun;Park, Kwang-Suk
    • 대한자기공명의과학회:학술대회논문집
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    • 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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    • pp.133-133
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    • 2002
  • Purpose: The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods: MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions: (x, y, z):(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows: TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age:21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes: It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw|Vx|, G=λw|Vy|, B=λw|Vz|, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

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색도플러 초음파검사에 의한 경추골동맥 기시부 관찰 (Visualization of the Origin of the Vertebral Arteries with Color Doppler Sonography)

  • 윤석환;이원홍;이대형
    • 대한방사선기술학회지:방사선기술과학
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    • 제32권1호
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    • pp.87-93
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    • 2009
  • 배경/목적 : 경추골동맥 기시부의 동맥경화증은 경추기저 국소빈혈증의 위험인자 중 하나이기 때문에 경추골동맥 기시부를 확인해야 할 필요가 있다. 색도플러 초음파검사에 의한 경추골동맥 기시부의 관찰 및 평가는 기술적으로 어려움이 있으며, 특히 왼쪽 기시부는 더욱 그렇다. 이 연구의 목적은 색도플러 초음파검사 시경추골동맥 기시부의 관찰률을 높이는 것이다. 대상 및 방법 : 경동맥을 포함한 경추골동맥의 색도플러 초음파검사가 198명에 대해 시행되었다. 경추골동맥 기시부를 다른 혈관의 기시부와 더 쉽게 구분하기 위해 목 윗부분의 경추동맥에서부터 쇄골하동맥 측으로 검사를 시행하였다. 검사 기술적으로 경추골동맥 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀고, 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도하였다. 경추골동맥 기시부의 깊이와 위 세 가지 방법 및 그에 따른 관찰률을 확인하기 위하여, 검사된 초음파 영상에서 관찰된 경추골동맥 기시부의 위치를 3.0 cm 이하와 그 이상으로 구분하였다. 결 과 : 오른쪽 경추골동맥 기시부는 97%, 왼쪽 경추골동맥 기시부는 92%에서 관찰되었다. 3.0 cm 이하에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 98.6%, 1.4%, 그리고 0.0%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 81.2%, 14.6%, 그리고 4.2%이었다. 3.0 cm 이하에서 관찰된 왼쪽쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 85.4%, 10.7%, 그리고 3.9%%이었다. 그리고 3.0 cm 보다 더 깊은 위치에서 관찰된 오른쪽 경추골동맥 기시부 중 자연스러운 자세, 트랜스듀서 밀기, 그리고 어깨 밀기에서 관찰된 경우는 각각 55.7%, 30.4%, 그리고 13.9%이었다. 결 론 : 경추골동맥의 색도플러 초음파검사에서 그 기시부가 바로누운자세의 자연스러운 위치에서 관찰되지 않을 경우, 초음파 트랜스듀서를 쇄골 측으로 밀거나 그래도 관찰되지 않을 경우 다른 손으로 어깨를 밀어 관찰을 시도한다면, 관찰률을 좀더 높일 수 있을 것으로 사료된다.

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중등학교 교과서 황해난류 오개념 분석 및 해류 데이터 시각화 수업자료 개발 (Misconception on the Yellow Sea Warm Current in Secondary-School Textbooks and Development of Teaching Materials for Ocean Current Data Visualization)

  • 김수란;박경애;변도성;정광영;최병주
    • 한국지구과학회지
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    • 제44권1호
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    • pp.13-35
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    • 2023
  • 지구의 기후 변화를 유도하고 제어하는 가장 중요한 역할을 하는 것은 해양의 해류이다. 황해는 수심이 동해에 비해 매우 얕고, 다양한 바람과 조류, 강물의 유입, 동중국해에서의 해수 유입 등 외력의 영향으로 해수의 순환과 해류가 상당히 복잡하다. 황해난류는 겨울철 황해의 대표적인 해류로서 겨울철 황해와 동중국해 바람 변동성과 밀접한 관련이 있으며, 황해의 수온과 염분 분포에 큰 영향을 주어서 중등학교 교과서에서 중요하게 다루어질 필요성이 있다. 2015 개정 교육과정 기반 중등학교 과학 및 지구과학 교과서의 황해난류와 관련된 내용을 분석하였다. 또한 해류의 시간 변동성에 대한 교사들의 인식을 조사하기 위해 중등학교 과학 교사들을 대상으로 설문조사를 실시하였다. 대부분의 교사들은 황해난류가 우리나라 서해안으로 연중 북상하고 있으며 일반적인 난류와 같이 여름철에 강하다는 잘못된 지식을 가지고 있는 것으로 나타났다. 황해난류는 해류의 세기가 강한 계절변동성을 가지는 북한한류와 달리 해류 자체가 연중 항시 존재하지 않으며 겨울철에만 발생하는 해류이다. 이러한 교사들의 교과내용 지식에 대한 오류는 북한한류가 겨울철에 강하다는 오개념을 가지게 된 연유와 유사한 배경을 가지고 있었다. 따라서 본 연구에서는 황해난류에 대한 교과서 내용의 오류를 분석하여 제시하였다. 또한 학생들과 교사들의 데이터 리터러시 함양을 위하여 탐구활동에서 활용할 수 있는 황해난류에 대한 수업 자료를 개발하였다. 황해 해수면 온도를 가시화할 수 있는 GUI 프로그램을 소개하였고, WOA (World Ocean Atlas) 2018 해양 실측 수온 및 염분자료와 국립해양조사원에서 생성한 해양 수치모델 재분석자료를 활용하여 수온과 염분의 공간 분포를 도시하는 자료를 개발하여 제시하였다. 이러한 해양 자료를 활용한 데이터 시각화과정은 교사들의 오개념을 개선하고, 나아가 학생들과 교사들의 해양 리터러시뿐만 아니라 데이터 리터러시도 제고하는 계기가 될 것으로 기대된다.