• 한국화재소방학회논문지
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• 제24권4호
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• pp.92-97
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• 2010

부산 실내사격장 화재의 원인을 추정하고 화재안전대책을 강구하기 위해 화재 시뮬레이션과 사격장 화재의 사례조사를 수행하였다. 현장조사와 잔류화약 분말에 대한 사격시험도 실시하였다. 총구불꽃과 탄자 받이에서의 스파크의 흔적이 CCTV 녹화영상에 나타나지 않았고, 유탄의 충격에 잔류화약이 점화하지 않았다. 따라서 잠재적 점화원 중 담뱃불이 가장 유력한 점화원으로 추정되었다. 또, 사격실에서의 폭발원인은 폴리우레탄 흡음재와 흡음재에 축적된 잔류화약 분말의 격렬한 연소 때문으로 판단되었다. 한편, 실내 사격장의 안전대책으로 프로파일 폴리우레탄 흡음재의 사용금지, 잔류화약 제거와 철저한 관리, 탄자받이의 강구조물 제거 등이 필요하다.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.359-368
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• 2020

This research seeks to explain factors and relationship models of entrepreneurs capable of building service innovations in Andaman coast with the ultimate aim to ignite sufficient development of regional tourism, increase working potentials, and provide a guideline for tour operations. Initially, document examination and discussions with five experts were conducted to build in-depth interview questions. 19 entrepreneurs were interviewed to examine factors involved and we consulted later with the five experts and six successful entrepreneurs in the regions, as well as with the representatives of the Association of Thai Tour Operators and Tourism Authority of Thailand (TAT) of Phuket, Krabi, and Trang. The results were analyzed according to the theory of resource-based and innovative entrepreneurs. The factors obtained were generated from systematic causes: Nature of Entrepreneurships and Organizational capabilities, the mediator variables of Service Innovation Capability; and Organizational Performance (non-finance). Moreover, the external factors needing to be adjusted regarding the environmental changes were described. The tour operators are suggested to build networking to increase tourism potential with sustainability by providing the entrepreneurs opportunities to be involved in tourism development, accessing the knowledge, technology and innovations resulting in sustainable tourism, quality livelihood, and sustainable ecological management of communities.

• 한국추진공학회지
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• 제9권3호
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• pp.60-65
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• 2005

본 연구는 기존의 폭발볼트와는 달리 작동에 필요한 전원의 공급 없이 수행하면서, 또한 지연기능까지 포함한 비전기식 지연형 폭발볼트에 관한 것이다. 즉 비전기식 작동방법을 이용하여 전원 공급 장치를 없앨 수 있기 때문에 분리장치의 소형화가 가능해졌고, 이를 위하여 기존 폭발볼트의 작동 메카니즘과는 다른 새로운 개념의 메카니즘을 적용하였고, 또한 지연기능을 추가하기 위하여 작동 메카니즘 개발과 별도로 지연장치를 개발하였다. 전원을 사용하지 않고 작동하는 착화장치를 설계하기 위하여 폭발볼트가 결합된 비행체에서 발생하는 공기의 저항력을 이용하였다. 고속으로 비행하는 발사체의 속도를 줄이고 안전한 착륙을 위한 낙하 시스템의 설계에 고려될 수 있는 장치라고 생각된다.

• 한국가스학회지
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• 제16권2호
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• pp.45-51
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• 2012

최소자연발화온도는 가연성혼합물이 화염이나 스파크 없이 주위로부터 충분한 열에너지를 받아서 스스로 발화하는 최저온도를 말한다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 n-Pentanol+Ethylbenzene계를 구성하는 순수물질과 혼합물의 최소자연발화온도를 측정하였다. Pentanol과 Ethylbenzene의 측정된 최소자연발화온도는 각 각 $285^{\circ}C$, $475^{\circ}C$ 였다. 그리고 n-Pentanol+Ethylbenzene 계의 예측된 최소자연발화온도는 실험값과 적은 평균절대오차에서 일치하였다.

• International Journal of Automotive Technology
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• 제7권1호
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• pp.17-23
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• 2006

An experimental study was carried out to obtain the fundamental data about the effect of sub-chamber on pre-mixture combustion. A eve (constant volume combustor) divided into a sub-chamber and a main chamber was used in this experiment. The volume of the sub-chamber was varid trom $0.45\%$ to $1.4\%$ about the whole combustion chamber. The sub-chamber has twelve narrow radial passage holes and a spark plug to ignite the pre-mixture. As the ignition occurs in the sub-chamber by a spark discharge, burned and unburned gas including a great number of radicals is injected into the main chamber, then the multi-point ignition occurs in the main chamber. The combustion pressure is measured to calculate the burning velocity mainly as a function of the sub-chamber volume, the diameter of the passage holes, and the equivalence ratio. In the case of RI (radical ignition) methods, the overall burning time became very short and the maximum burning pressure was slightly increased as compared with that of SI (spark ignition) method. The optimum design value of the sub-chamber is near 0.11 $cm^{-l}$ in the ratio of total area of holes to the sub-chamber volume.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.425-435
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• 2014

Simulation studies on catalytic methanation reaction in externally cooled tubular reactor filled with monolithic catalysts were carried out using a general purpose modelling tool $gPROMS^{(R)}$. We investigated the effects of operating parameters such as gas space velocity, temperature and pressure of feeding gas on temperature distribution inside the reactor, overall CO conversion, and chemical composition of product gas. In general, performance of methanation reaction is favored under low temperature and high pressure for a wide range of their values. However, methane production becomes negligible at temperatures below 573K when the reactor temperature is not high enough to ignite methanation reaction. Capacity enhancement of the reactor by increasing gas space velocity and/or gas inlet pressure resulted no significant reduction in reactor performance and heat transfer property of catalyst.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.499-504
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• 2019

Due to the rapid spread and low minimum ignition energy of hydrogen, rupture is highly likely to cause fire, explosion and major accidents. The self-ignition of high-pressure hydrogen is highly likely to ignite immediately when it leaks from an open space, resulting in jet fire. Results of the diffusion and leakage simulation show that jet effect occurs from the leakage source to a certain distance. And at the end of location, the vapor cloud explosion can be occurred due to the formation of hydrogen vapor clouds by built-up. In the result, it is important that depending on the time of ignition, a jet fire or a vapor cloud explosion may occur. Therefore, it is necessary to take into account jet effect by location of leakage source and establish a damage minimizing plan for the possible jet fire or vapor cloud explosion. And it is required to any kind of measurements such as an interlock system to prevent hydrogen leakage or minimize the amount of leakage when detecting leakage of gas.

• 전기학회논문지
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• 제61권8호
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• pp.1148-1152
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• 2012

The vegetable-based insulating oils are substitutes for mineral oils in oil-filled transformer. The important properties of vegetable insulating oil is their higher flash/fire point and biodegradability than conventional mineral oils. The large oil-filled transformer eliminate the risk of explosion and fire should the transformer fail and oil ignite owing to high flash/fire point of vegetable insulating oil. In addition, higher biodegradability of vegetable insulating oils can let the oil spill damage reduced. In this experiment, the real oil-filled transformers using mineral oil and vegetable oil have accelerated aging. After working on the 100% accelerated aging experiment were conducted comparing the transformer. The hottest-spot temperature using thermal coefficients were calculated to determin the degree of accelerated aging. As a result, apply mineral oil transformer in accordance with the accelerated aging life come to an end. In contrast, vegetable insulating oils showed the opposite characteristics. Vegetable insulating oil compared to the mineral oil are found to be an long life. As a result, the vegetable oil has a long-term stability.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1332-1342
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• 2014

This paper proposes a novel test circuit for SiC transistors. On-state resistance under practical application conditions is an important characteristic for the device reliability and conduction efficiency of SiC transistors. In order to measure the on-state resistance in practical applications, high voltage is needed, and high current is also necessary to ignite performance for the devices. A soft-switching circuit based on synchronous buck topology is developed in this paper. To provide high-voltage and high-current stresses for the devices without additional spikes and oscillations, a resonant circuit has been introduced. Using the novel circuit technology, soft-switching can be successfully realized for all the switches. Furthermore, in order to achieve accurate measurement of on-state resistance under switching operations, an active clamp circuit is employed. Operation principle and design analysis of the circuit are discussed. The dynamic measurement method is illustrated in detail. Simulation and experiments were carried out to verify the feasibility of the circuit. A special test circuit has been developed and built. Experimental results confirm that the proposed circuit gives a good insight of the devices performance in real applications.

• 한국군사과학기술학회지
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• 제8권2호
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• pp.58-66
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• 2005

This paper presents miniaturized setback generators based on the conversion of mechanical energy into electrical energy for military applications, especially power supply for electronic fuzes. In order to minimize the volume of setback generators, a ring-shaped magnet enclosing a coil assembly is adopted. A mechanical safety system, shear plate, is used as a release mechanism of the setback generators to prevent the generators from operating accidentally. The setback generators are intended not to ignite an electrical detonator but to charge a capacitor which is capable of driving electronic circuit of fuze. We design the setback generators using the simulation results of an electromagnetic analysis tool, $Maxwell^{(R)}$ 2D. In experimental study, we perform safety tests of the shear plate and firing tests of the fabricated setback generators. The present setback generators show that the voltage of 14.2V is charged at the capacitor of $30{\mu}F$ within the charging time of 0.68msec and the critical acceleration for safety is 5,000G, thus verifying that the setback generators with a ring-shaped permanent magnet can be applicable to the power supply of small-caliber electronic fuze.