• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.249-252
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• 2012

Experiments have been conducted to clarify flame spread behavior over electrical wire near the end of wire with applied AC electric fields. It is seen that the flame spread behavior near the end of wire with applied AC electric fields are quite different from that in temporally linearly-increasing flame position. The flame spread behavior can be categorized into three regimes based on the relevance of flame shape and the slanted direction of spread flame to spread rate. Detailed explanations on the characteristics are made through thermal balance mechanism. Also, the effect of drop of molten PE and fuel vapor-jet in flame spread is also discussed.

• 방재기술
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• 통권56호
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• pp.20-29
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• 2014

• 한국연소학회지
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• 제7권1호
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• pp.15-22
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• 2002

Flame spread experiments of a fuel droplet array were performed using a microgravity environment. N-decane, 1-octadecene, and the blends (50% : 50% vol.) of these fuels were used and the experiments were conducted at pressures up to 5.0 MPa, which are over the critical pressure of these fuels. Observations of the flame spread phenomenon were conducted for OH radical emission images recorded using a high-speed video camera. The flame spread rates were calculated based on the time history of the spreading forehead of the OH emission images. The flame spread rate of the n-decane droplet-array decreased with pressure and had its minimum at a pressure around half of the critical pressure and then increased again with pressure. It had its maximum at a pressure over the critical pressure and then decreased gradually. The pressure dependence of flame spread rate of 1-octadecene were similar to those of n-decan, but the magnitude of the spread rate was much smaller than that of n-decane. The variation of the flame spread for the blended fuel was similar to that of n-decane in the pressure range from atmospheric pressure to near the critical pressure of the blended fuel. When the pressure increased further, it approached to that of 1-octadecene. Numerically estimated gas-liquid equilibrium states proved that almost all the fuel gas which evaporated from the droplet at ordinary pressure consisted of n-decane whereas near and over the critical pressure, the composition of the fuel gas was almost the same as that of the liquid phase, so that the effects of 1-octadecene on the flame spread rate was significant.

• 한국농공학회논문집
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• 제53권1호
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• pp.29-36
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• 2011

HPAI (High pathogenic avian influenza) which is a disease legally designated as an epidemic generally shows rapid spread of disease resulting in high mortality rate as well as severe economic damages. Because Korea is contiguous with China and southeast Asia where HPAI have occurred frequently, there is a high risk for HPAI outbreak. A prompt treatment against epidemics is most important for prevention of disease spread. The spread of HPAI should be considered by both direct and indirect contact as well as various spread factors including airborne spread. There are high risk of rapid propagation of HPAI flowing through the air because of collective farms mostly in Korea. Field experiments for the mechanism of disease spread have limitations such as unstable weather condition and difficulties in maintaining experimental conditions. In this study, therefore, computational fluid dynamics which has been actively used for mass transfer modeling were adapted. Korea has complex terrains and many livestock farms are located in the mountain regions. GIS numerical map was used to estimate spreads of virus attached aerosol by means of designing three dimensional complicated geometry including farm location, road network, related facilities. This can be used as back data in order to take preventive measures against HPAI occurrence and spread.

• Earthquakes and Structures
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• 제7권6호
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• pp.1001-1024
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• 2014

The size of spread footings was found to be unnecessarily large from some actual engineering practices constructed in Taiwan, due to the strict design provisions related to footing uplift. According to the earlier design code in Taiwan, the footing uplift involving separation of footing from subsoil was permitted to be only up to one-half of the foundation base area, as the applied moment reaches the value of plastic moment capacity of the column. The reason for this provision was that rocking of spread footings was not a favorable mechanism. However, recent research has indicated that rocking itself may not be detrimental to seismic performance and, in fact, may act as a form of seismic isolation mechanism. In order to clarify the effects of the relative strength between column and foundation on the rocking behavior of a column, six circular reinforced concrete (RC) columns were designed and constructed and a series of rocking experiments were performed. During the tests, columns rested on a rubber pad to allow rocking to take place. Experimental variables included the dimensions of the footings, the strength and ductility capacity of the columns and the intensity of the applied earthquake. Experimental data for the six circular RC columns subjected to quasi-static and pseudo-dynamic loading are presented. Results of each cyclic loading test are compared against the benchmark test with fixed-base conditions. By comparing the experimental responses of the specimens with different design details, a key parameter of rocking behavior related to footing size and column strength is identified. For a properly designed column with the parameter higher than 1, the beneficial effects of rocking in reducing ductility and the strength demand of columns is verified.

• E2M - 전기 전자와 첨단 소재
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• 제7권4호
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• pp.281-288
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• 1994

According to spread volume of B(BiPbCuO) layer, composition ratio and each stage of sintering process, we studied stability of high Tc superconductor phase and generation and growth movement of superconducting phase. The dual layer composed of SrCaCuO and BiPbCuO compound were prepared to develop the Bi-2223 superconductor[108K] through interaction and diffusion during sintering process. The dual layer samples were sintered at 830.deg. C for 0-210 hours. From the result, the optimum conditions were : spread volume(A:B=1:0.6), sintering time(210h) and composition ratio(A:S $r_{2}$C $a_{2}$C $u_{2}$- $O_{x}$, B:B $i_{1.9}$P $b_{0.5}$C $u_{3}$ $O_{y}$) at 830.deg. C.. C.C.C.

• 한국연소학회지
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• 제22권3호
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• pp.1-7
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• 2017

An experimental study on spreading flame over electrical wire, which was insulated by Polyethylene(PE) and had different diameters, was conducted with applied AC electric field. The result showed that the flame spread rate decreased in increase of the diameter of insulator at a fixed electric field. The flame spread rate exhibited increase or decrease tendency with applied AC electric field, having three distinct regimes depending on applied voltage and frequency. In each regime, the flame spread rate was characterized by physical parameters of applied electric fields and wire dimensions, and the behaviors could be explained by a thermal balance mechanism.

• 정보보호학회논문지
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• 제23권6호
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• pp.1001-1006
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• 2013

본 논문에서는 최근 스마트폰과 지능형 로봇 분야에서 급속도로 확산되고 있는 유해 멀티미디어의 유해성을 판별하기 위해 유해정보 판별 메커니즘 및 판별 메커니즘 성능 분석에 대해서 설명한다. 이러한 판별 기술들을 기반으로 멀티미디어(이미지, 비디오) 기반의 개별 유해 특징 요소를 정의한다. 또한 시각적 특징을 모델링하여 유해 멀티미디어 콘텐츠의 유해성을 분석한다.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2005년도 하계학술대회
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• pp.67-73
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• 2005

For power constrained applications, IEEE 802.15.4 networks may be operated in beacon enabled mode with inactive period. In this paper, we propose the Virtual Arrival Mechanism (VAM) to avoid the congestion at the beginning of each contention access period (CAP). Virtual Arrival Mechanism (VAM) is a kind of traffic shaping that spread the traffics congested at the beginning of CAP into the whole CAP. By using VAM, collisions and energy consumption can be reduced. Finally, we evaluate the performance enhancement of VAM using NS-2 simulator.

• Journal of Korean Neurosurgical Society
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• 제29권8호
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• pp.1085-1088
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• 2000

Spinal intradural extramedullary metastasis are very rare. The authors report a case of spinal metastasis at the T5 level in the intradural extramedullary space in a 76-year-old man who presented with paraparesis and sciatica. Preoper-ative neuroradiologic imaging studies were highly suggestive of intradural mass lesion with compressive myelopathy. Pathology revealed metastatic squamous cell carcinoma. We describle the mechanism of tumor spread in intradural spinal metastasis.