• 한국화재소방학회논문지
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• 제12권2호
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• pp.29-42
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• 1998

최근에 소방안천과 관련된 화재 현상의 수치해석 연구률 위한 컴퓨터의 이용이 크게 중가하고 있는 실정이다. 밀폐된 구획의 창유리(3mm, 4mm 두쩨) 파단시 화재의 동륙성을 초사하기 위하여 zone형 컴퓨터 수치해석 프로그햄인 FASTLite(version 1.1.2)와 창유리 파단 시간 계산 프로그랩인 BREAKl(ver¬S sion 1.0)을 사용하여 foam sofa 화재에 대한 모의 실험융 하였다. 본 연구률 흉하여 개방- 혹온 멀쩨-상태의 구획 화재의 동륙성과 밀떼된 구획의 창유리 파단시 화재 동특성 사이에 큰 차이가 있옴을 확인하였다. 또 4mm 두째 유리의 경우 벼쟁상 연소로 인해 발생 . 축객된 미연소 가연성 가스에 의해 backdraft 현상이 발생합융 볼 수 있었고, 않run와 4mm 두께의 유리 내 . 외면에 온도차가 있음을 확인하였다. 본 연구의 결과는 소방대원의 화재진압 혹은 피난을 위한 소방천술과 소방안전 공학도의 구획 화재 관련 컴퓨터 수치 혜석 프로그램의 운영 기법을 향상시키는데 큰 도용이 되리라 생각된다.

• International Journal of Automotive Technology
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• 제5권3호
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• pp.209-213
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• 2004

The objective of this paper is to introduce the noise reduction characteristics of a double gap system, which is composed of two air-gaps and two partition sheets. The resonance of acoustic modes of an enclosed cavity can be effectively suppressed by installing the double gap system in the cavity. It is revealed from a simple, one-dimensional model that the double gap system is more effective than the single gap system that consists of one air-gap and one partition sheet, in that the former requires a smaller space than the latter. Finally, these theoretical conclusions are verified by comparison experiments using an actually manufactured enclosed cavity, of which the boundary surfaces are made of thick panels that can be assumed as rigid walls.

• International Journal of Aeronautical and Space Sciences
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• 제2권2호
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• pp.19-27
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• 2001

This research attempts to find an active control strategy which reduces acoustic power and acoustic energy in lightly-damped enclosed sound field such as a vehicle compartment or an operating room of heavy industrial machinery. An active control strategy, which takes into consideration of the acoustic radiation power of the source as a cost function, is formulated and examined to find capability of reducing noise. An adaptive filtering algorithm for sound power control is suggested and implemented to control lightly-damped sound field. To verify the method, sound power based active noise control algorithm was implemented on a rectangular box with lightly-damped wall, and popular acoustic energy based control with modal coupling reduction was performed to compare the noise reduction performance. It was shown that a total sound power based strategy provides a practical mean for global noise reduction for lightly damped sound field.

• 대한조선학회논문집
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• 제54권4호
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• pp.294-300
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• 2017

The offshore installations and ships are the structures most likely to be exposed to hazards such as hydrocarbon fire and/or explosion. Developing proactive measures to prevent the escalation of such events thus requires detailed knowledge of the related phenomena and their consequences. $CO_2$ extinguishing systems are extensively used for fire accidents of on-and offshore installations because of outstanding performance and low cost. There is, however, the risk of carbon dioxide system which enumerates many of the fatalities by suffocation associated with industrial fire protection requirements. Therefore, the aim of this study is to perform the prediction of fire suppression characteristics of the carbon dioxide system in realistic enclosed compartment area of ships and propose $CO_2$ extinguish fire fighting system for preventing suffocation accidents during fire fighting. According to CFD calculations, it can be observed and assessed that various fire profiles with $CO_2$ and $O_2$ mole fraction in the target enclosed compartment area are applicable within the proposed system. Additionally, the design of fire safety system of ships and offshore installations can utilize ventilation system and/or layout arrangement through the proposed system.

• 한국자동차공학회논문집
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• 제13권6호
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• pp.163-169
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• 2005

A theoretical formulation on the forced acoustic response of an enclosed cavity having a double air-gap resonator on one of boundary panels of the cavity is developed in the paper. The double gap resonator consists of two air-gaps and two partition sheets as in the author's previous papers. This paper reveals that the double gap resonator reduces the level of a target noise peak by splitting the peak as two small peaks, and that it is more effective when it is designed so that the upper gap thickness is larger than the lower gap thickness under the constraint that the entire gap thickness is fixed as a constant value. Finally, verification experiments show that the theoretical formulation and analysis results are valid by comparing theoretical results with experimental ones.

• 터널과지하공간
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• 제8권1호
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• pp.8-16
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• 1998

The first purpose of this study is to verify the application of computer modelling to a enclosed space fire. The second one is to determine temperature distribution for the three different ventilation types in case of a enclosed space fire. The third one is to find out the ventilation direction and ventilation quantity to remove effectively heat and combustion products generated by a fire in variable air volume(VAV) system. Firstly, compared with experimental results of Lawrence Livermore National Laboratory(LLNL), numerical results show good agreements. Secondly, among three different ventilation types, the numerical analyses show the highest temperature distribution in occupied zone(up to 1.8 m from bottom) from firing moment to 100 sec. when supply ducts are placed in ceiling and extract duct is placed close to the bottom on side walls. This is due to disadvantageous position of extract duct in ventilating high temperature air which rise because of buoyancy force. Thirdly, this study finds out effective ventilation direction and ventilation quantity to remove heat and combustion products generated by a fire by using VAV system. $CO_2$ concentration is used as a fire fume removal index. As soon as a fire happens, ventilation direction is changed in order to gather and drive out fire fumes. In case of three times ventilation quantity of ordinary one, $CO_2$ concentration and temperature have begun to decrease at 120 sec. after firing, i.e.fire fumes have begun to be removed.

• Anatomy and Cell Biology
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• 제57권1호
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• pp.25-30
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• 2024

The aim of this study was to identify the anatomical feature of retaining ligament and fat compartment on the lower eyelid and infraorbital region using a histological method, and to investigate clear definitions for them which could be used generally in the clinical area. Eighteen specimens from eight fresh Korean cadavers were stained with Masson trichrome or hematoxylin and eosin. The ligamentous and fascial fibrous tissue were clearly identified. The ligamentous fibrous tissue which traversed in the superficial and deep fat layer was skin ligament and orbicularis retaining ligament (ORL). The fascial fibrous tissue enclosed the orbicularis oculi muscle (OOc) and circumferencial adipose tissue. Based on the ligamentous and fascial structure, three fat compartments, septal, suborbicularis oculi and infraorbital fat compartment, could be identified. The OOc attached to orbital rim and dermis by ORL and skin ligament, and the muscle fascicle and fat fascicle provided the connection point to the ORL and skin ligament as enclosing all muscle and fat tissue. The combination of the force made by the skin ligament in the lower eyelid and ORL may decide the level and form of the infraorbital grooves.

• 한국철도학회논문집
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• 제9권3호
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• pp.291-297
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• 2006

The present study investigated the effect of fire suppression using a mid-low pressure water mist in a carriage fire. The fire extinguishing time and temperature distributions below ceiling in the enclosed compartment of $2.9m{\times}2.8m{\times}5.0m$ were measured by stopwatch and k-type thermocouples for various fire positions. The numerical simulations were extensively performed using. Fire Dynamics Simulator(FDS, Ver. 4.0) code and the predictions were compared with experimental data. The prediction results showed good agreement with the measured maximum temperature in the all cases. Whereas the predicted temperature was about $40^{\circ}C$ higher than the measured one after operating of water mist. The predicted fire extinguishing times were compared with those of measured data. Fires are extinguished within 200 seconds at the experiment in Case 2 and Case 3. But in Case 1 fire was not extinguished in the numerical simulation. The reason of the discrepancy between predicted and measured data was that a simple suppression algorithm has been implemented in FDS. Also, various databases of fire properties for combustible materials and more elaborate model considering the water mist were required fur better predictions of the cooling and suffocation effect.

• 공업화학
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• 제34권4호
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• pp.421-425
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• 2023

Polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), 그리고 polyacetal을 포함하는 일부 플라스틱류에 대한 연기특성을 조사하였다. 연기밀도는 ISO 5659-2의 기준에 의해 연기밀도시험기를 이용하여 정적인 연기 특성의 관련 값을 측정하였다. 또한 불꽃을 동반하는 연소와 불꽃을 동반하지 않는 연소를 구분하여 측정하였다. 불꽃방식의 복사열 50 kW/m² 의 조건하에서 연기의 최대비광학밀도(D_m) 측정값은 PMMA (401.26)가 최저로, PVC (1345.04)가 최대로 나타났다. 또한 비불꽃방식의 복사열 50 kW/m² 의 조건하에서 연기의 D_m 측정값은 PMMA (262.82) 가 최저로, PVC (1385.43)가 최대로 나타났다. 대상물의 연소 시 연기발생은 복사열 유속의 영향을 상당히 받으며, 탄화성 플라스틱은 연소 시 비탄화성 플라스틱보다 높은 연기 발생량을 나타내었다. 주 고분자 사슬에 방향족 그룹이 있는 폴리머는 열분해로 인해 다량의 숯이 생성되므로 다량의 연기를 발생시켰다.

• 한국임상수의학회지
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• 제26권6호
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• pp.595-599
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• 2009

한국산 양축 엘크사슴 (Cervus elaphus)의 심장 조직에서 Sarcocystis grueneri 양 포낭을 광학 및 투과전자현미경으로 관찰하였다. 심장조직의 병리소견에서는 다수의 포낭이 관찰되었으며, 염증 및 근섬유의 변성은 관찰되지 않았다. 염증 및 근섬유의 변성은 관찰되지 않았으며 다수의 포낭이 관찰되었다. 포낭은 난형에서 난원형 이었으며, 크기는 90-170$\times$ 110-380 ${\mu}m$로 계측되었다. 투과전자현미경 소견에서 포낭은 숙주세포 유래의 sarcoplasm에 싸여 있었고 0.45-0.6 ${\mu}m$ 두께의 매우 얇은 포낭벽을 갖고 있었으며, 포낭벽은 protrusion 및 ground substance로 구성되어 있었다. 다수의 길고 가느다란 protrusion 층의 높이는 0.2-0.3 ${\mu}m$, protrusion의 길이는 최장 4.2 ${\mu}m$로 계측되었다. Protrusion은 포낭의 표면과 평행하게 주행하였다. 포낭은 중격에 의하여 소실로 나뉘어져 있었고 소실에는 크기가 약 $15\times4\;{\mu}m$인 다수의 merozoites가 존재하였다. 관찰된 모든 포낭은 같은 발육기를 갖고 있었다. Merozoite는 4개 구역(micronemes and rhoptries, amylopectin granules, 핵 및 amylopectin granules)으로 구분되었으며 7-11 개의 rhoptry가 충체의 전방에 분포하였다.