• Title/Summary/Keyword: Broken plane

Search Result 18, Processing Time 0.031 seconds

An Experimental Study on the Fire Investigation to the Broken Plane Types of Glass (유리 파단면의 화재감식에 관한 실험적 연구)

  • Mun, Yong-Soo;Kong, Ha-Sung
    • Journal of the Korea Safety Management & Science
    • /
    • v.10 no.4
    • /
    • pp.105-109
    • /
    • 2008
  • The purpose of this study is to distinguish the causes of broken glass on doors or windows when it is originally kept among the remains on the floor in fire site - whether it was broken due to heating or outer power-through test and characteristics of the broken plane including the pattern on the plane. Addition to it, the study tries to find characteristics to judge the point and direction of breakdown through the analysis of glass broken by outer power. With two assumed causes - a) breakdown due to heating and b) breakdown due to outer power-3 pieces of glass plates ($30cm{\times}30cm{\times}5mm$) were tested for each case, getting the results as following: First, for the glass broken due to the change of temperature, the broken plane is of slow and smooth curve without any pattern. Second, for the glass broken due to outer power, with the impact point as the center, the glass shows breakdown of radial type and the side shows breakdown of near-perpendicular type. The far the broken piece is from the impact point, the bigger the size is. The broken piece at the impact point is of long triangle type and the two long planes of the triangle shows semi-arc with the center of breakdown point and the other plane shows opposite pattern. Third, when glass that is damaged by outer power is heated, damaged forms and side patterns of the glass that is damaged by outer power are heated and disappeared.

A study on the identification of the causes according to the broken plane types of glass (유리 파단면의 형태 식별에 따른 파손원인 감정에 대한 연구)

  • Mun, Yong-Su;Sa, Sang-Yeol;Choe, Min-Seok;Choe, Jae-Ho;Kim, Yong-Su
    • Journal of Korean Institute of Fire Investigation
    • /
    • v.3 no.1
    • /
    • pp.12-15
    • /
    • 2003
  • The purpose of this study is to distinguish the causes of broken glass from doors or windows when it is found being originally kept among the remains on the floor in fire site - whether it was broken due to heating or by outer power through test and the properties of the broken plane including the pattern on the plane. Addition to it, the study tries to find characteristics for judging the point and direction of breakdown through the analysis of glass broken by outer power. With two causes assumed - a. breakdown due to heating and b. breakdown due to outer power - 3 pieces of glass plates $(30cm{\times}30cm{\times}5mm)$ for each case were tested, getting the results as following: 1. For the glass broken due to the change of temperature The broken plane is of slow curve and smooth without any pattern. 2. For the broken due to outer power With the impact point as the center, the shows breakdown of radial type and the side shows breakdown of near-perpendicular type. The far the broken piece is from the impact point, the bigger the size is. The broken piece at the impact point is of long triangle type and the two long planes of the triangle shows semi-arc with the center of breakdown point and the other plane shows opposite pattern 3. Change of the pattern and type of the glass due to outer power The pattern and type of the glass due to outer power shows change due to heatihg.

  • PDF

Investigation on the propagation mechanism of explosion stress wave in underground mining

  • Wang, Jiachen;Liu, Fei;Zhang, Jinwang
    • Geomechanics and Engineering
    • /
    • v.17 no.3
    • /
    • pp.295-305
    • /
    • 2019
  • The bedding plane has a significant influence on the effect of blasting fragmentation and the overall performance of underground mining. This paper explores the effects of fragmentation of the bedding plane and different angles by using the numerical analysis. ANSYS/LS-DYNA code was used for the implementation of the models. The models include a dynamic compressive and tensile failure which is applied to simulate the fractures generated by the explosion. Firstly, the cracks propagation with the non-bedding plane in the coal with two boreholes detonated simultaneously is calculated and the particle velocity and maximum principal stress at different points from the borehole are also discussed. Secondly, different delay times between the two boreholes are calculated to explore its effects on the propagation of the fractures. The results indicate that the coal around the right borehole is broken more fully and the range of the cracks propagation expanded with the delay time increases. The peak particle velocity decreases first and then increases with the distance from the right borehole increasing. Thirdly, different angles between the bedding plane and the centerline of the two boreholes and the transmission coefficient of stress wave at a bedding plane are considered. The results indicated that with the angles increase, the number of the fractures decreases while the transmission coefficient increases.

Developing Expert System for Restoration to the Original Character Form of Ancient Relics Based on Image Processing and Computer Graphics (문화재의 문자 복원을 위한 전문가 시스템 개발: 영상처리 및 컴퓨터 그래픽스 활용을 중심으로)

  • Moon, Ho-Seok;Sohn, Myung-Ho
    • Journal of Information Technology Services
    • /
    • v.7 no.4
    • /
    • pp.139-149
    • /
    • 2008
  • We propose expert system for restoration the original character form of ancient relics based on image processing and computer graphics. Letters engraved in relief like relics and intaglio like curved tombstones and letters engraved in plane or curved part of cultural asset may have been broken by a lot of rubbed copy, a long time and tide. In this paper, we suggest a new method for extracting and recovering the broken letters of cultural asset into an original form by using Z-map, morphological filter, and high frequency filter. Based on the suggested method. we develop the character recovering system.

Study on the Semi-Analytical Ice Load Calculation Methods for the Ice-Breaking Simulation (쇄빙시뮬레이션을 위한 반해석적 빙하중 계산법 고찰)

  • Kim, Jeong-Hwan;Jang, Beom-Seon;Kim, Yooil
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.57 no.6
    • /
    • pp.353-364
    • /
    • 2020
  • This paper presents the semi-analytical ice load calculation methods that are useful to simulate the ice-breaking process. Since the semi-analytical methods rely on the previously developed closed form equations or numerical analysis results, the user's exact understanding for the equations must be supported in order to use the methods properly. In this study, various failure modes of ice such as local crushing, in-plane splitting failure, out-of-plane bending failure and radial or circumferential cracking with rotation of the broken ice floe are considered. Based on the presented methods, the fracture modes were evaluated according to the size and thickness of ice. In addition, time series analysis for the ice-breaking process was performed on several ice conditions and the results were analyzed.

Analysis of Partial Discharge Signal Using Wavelet Transform (웨이브렛 변환을 이용한 부분방전 신호의 분석)

  • Lee, Hyun-Dong;Kim, Chung-Nyun;Park, Kwang-Seo;Lee, Kwang-Sik;Lee, Dong-In
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.49 no.11
    • /
    • pp.616-621
    • /
    • 2000
  • This paper deals with the multiresolution analysis of wavelet transform for partial discharge(PD). Test arrangement is based on the needle-plane electrode system and applied AC high voltage. The measured PD signal was decomposed into "approximations" and "details". The approximation are the high scale, low-frequency components of the PD signal. The details are the low-scale, high frequency components. The decomposition process are iterated to 3 level, with successive approximation being decomposed in turn, so that PD signal is broken down into many lower-resolution components. Through the procedure of signal wavelet transform, signal noise extraction and signal reconstruction, the signal is analyzed to determine the magnitude of PD.

  • PDF

Control of a- and c-plane Preferential Orientations of p-type CuCrO2 Thin Films

  • Kim, Se-Yun;Seong, Sang-Yun;Jo, Gwang-Min;Hong, Hyo-Gi;Kim, Jeong-Ju;Lee, Jun-Hyeong;Heo, Yeong-U
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2011.02a
    • /
    • pp.119-120
    • /
    • 2011
  • Kawazoe는 1997년 p-type TOS를 만들기 위해서는 3가지가 충족되어야 한다고 언급한바 있다. 첫 번째, 가시광영역에서 투명하기 위해서 cation의 d10s0이 가득 차야 한다. 가득 차지 않은 d10 shell은 광 흡수가 가능하여 투과도를 떨어뜨린다. N-type을 예로 들어 ZnO, TiO, In2O3가 각각 Zn2+, Ti4+, In3+가 되어 d shell을 가득 차게 만드는 것을 볼 수 있다. 두 번째, cation d10s0 shell은 산소의 2p shell과 overlap 되어야 한다. 이 valence band는 홀 전도를 더욱 좋게 한다. 예를 들어 Cu1+(3d), Ag1+(4d)가 해당한다. 세 번째로, 양이온과 산소간의 공유결합을 강하게 하기 위해서 결정학적 구조는 매우 중요하다. Delafossite 구조는 산소가 pseudo-tetrahedral 구조로서 공유결합에 유리하다. 이러한 환경은 O2- (2p6)을 형성하고 홀의 이동도를 증가시킨다. 예를 들어 Cu2O의 경우 앞의 2가지를 만족시키지만 광학적 특성에서 좋지 않다. 그 이유가 3번째 언급한 결정학적인 요인에 있다. 결정 계의 환경은 Cu2O를 따라가면서 3차원적인 연결을 2차원적으로 변형된 delafossite 구조에서는 quantum well이 형성되어 band gap이 커진다. 본 연구에서는 전기적 이방성을 가지고 있는 delafossite CuCrO2 상에서 우선배향을 일으키는 인자 중 기판을 변화시켜 실험을 진행하였다. 결과적으로 기판변화를 통해 우선배향조절이 가능하였으며 CuCrO2 박막을 시켰으며, 결정방향에 따른 전기적 물성의 이방성에 관한 연구는 계속 진행 중에 있다. c-plane sapphire 기판위에는 [00l]로 성장하는 반면, c-plane STO 기판 위에는 [015] 방향으로 성장하는 것을 확인하였다. 이러한 원인은 기판과 증착되는 박막간의 mismatch를 최소화 하여 strain을 줄이고, 계면에서의 Broken boning 수를 줄여 계면에너지를 낮추는 방법이기 때문일 것으로 예상된다. C-plane sapphire 기판위에 증착될 경우 증착온도가 증가함에 따라 c-축으로의 성장이 온전해지며 이에 따라 캐리어농도의 감소와 모빌리티의 증가가 급격하게 변하는 것을 확인할 수 있다. 반면 c-plane STO 기판에서는 증착온도에 따른 박막의 배향변화가 없으며 전기적 물성 변화 또한 비교적 작은 것을 간접적으로 확인하였다.

  • PDF

Effect of Carbon Content on the Shape of WC Grains during Liquid Phase Sintering of WC-Co Hard Metals (WC-Co 초경합금의 액상소결시 WC 입자형상에 미치는 탄소량의 영향)

  • 한석희;박종구;허무영
    • Journal of Powder Materials
    • /
    • v.6 no.4
    • /
    • pp.307-313
    • /
    • 1999
  • The effect of carbon content on the shape of WC grains dispersed in the Co-rich matrix during liquid phase sintering of WC-35%Co hard metals has been determined. The shape of WC grains was observed using SEM stereography after removing cobalt matrix with boiling hydrochloric acid solution. The WC grains changed from hexagonal to trigonal prism as the carbon content increased in the two-phase region of(WC + $\beta$ - Co), while the morphology of WC grains changed from trigonal to hexagonal shape as the carbon content decreased. The morphology of WC grains changes reversibly along with carbon loss or carbon pick-up. Morphology change of WC grains is attributed to crystal structure of WC, which has an asymmetric array of carbon atoms. There are two types of prismatic planes having different numbers of broken W-C bonds in WC grains. It is scrutinized that as the carbon content increases, the high energy prism planes grow fast and the crystals change from hexagonal to trigonal shape. On the other hand, when the carbon content decreases, the high energy prism planes are dissolved accompanying split of (100) plane into (101) and (101) planes.

  • PDF

Noise Reduction of a Underexpanded Supersonic Jet via Steady Blowing with Microjets (소형제트를 이용한 과소팽창 음속 제트에서의 소음저감)

  • Kim Jin-Hwa;Kim Jung Hoon;Yoo Jung Yul
    • Proceedings of the KSME Conference
    • /
    • 2002.08a
    • /
    • pp.747-750
    • /
    • 2002
  • An attempt to reduce supersonic Jet noise is carried out by using two steady microjets in a round jet. The jet is issued from a round sonic nozzle with an exit diameter of 10mm. Two micro-nozzles with an inside diameter of 1mm each are installed on the exit plane with an off-axis angle of $45^{\circ}$. Far-field noise was measured at a location 40 diameters off the jet axis. The angles between a microphone and the jet axis are $45^{\circ}\;and\;90^{\circ}$. For an injection rate less than $1{\%}$ of the main jet, screech tones were completely suppressed by the microjets. The reduction in the ovelall sound pressure levels were $2.4\;and\;2.7\;dB\;for\;90^{\circ}\;and\;45^{\circ}$ directions, respectively. The enhancement of mixing/spreading of the jet by the microjet was negligible. The reduction of noise is probably due to distorted shock cell structures and/or broken large scale vortical structures by the microjets.

  • PDF

Drift Motion Analysis on Horizontal Plane of a Two-Point Moored Oil Tanker (2점 계류된 선박에 대한 수평면상 표류운동 해석)

  • 이호영;임춘규
    • Journal of Ocean Engineering and Technology
    • /
    • v.18 no.3
    • /
    • pp.8-12
    • /
    • 2004
  • The anchor is laid on the seabed, and the main engine is working against incident environmental loads in a typhoon. As the main engine is broken Mum in the storm, the anchor chain is cut and the vessel drifts. Although a ship is moored by two-point mooring lines to maintain her position, it has crashed into a rock because of a typhoon, resulting in a possible accidental oil spillage. In this paper, we studied maintenance of a ship's position, which is analyzed based on the slow motion maneuvering equations considering wave, current, and wind. To estimate wave loads, the direct integration method is employed. The current forces are calculated, using MMG (Mathematical Modeling Group). Th two-point mooring forces are quasi-statistically evaluated, using the catenary equation. Th coefficients of wind forces are modeled from Isherwood's empirical data, and the variation of wind speed is estimated by wind spectrum. The nonlinear motions of a two-point moored ship are simulated, considering wave, current, and wind load, in specific domain of time.