• 한국산업안전학회:학술대회논문집
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• 한국안전학회 1998년도 추계 학술논문발표회 논문집
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• pp.179-182
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• 1998

It is widely recognized that conventional means for determining the minimum ignition energy(MIE) of powder are time-consuming and require operational skill. As a variety of new fine powders are being produced day by day in industry, there is an urgent need to a quicker and more economical means to measure MIE. To meet this requirement, we have developed a measurement system which employs a novel method to create an air/dust mixture in a miniature combustion box. In this system, the powder to be tested input into a hopper made of metal mesh, and successively fed downward to form a thin, curtain-like dust/air mixture by vibration. With this new apparatus, three type of powders -Lycopodium, Anthraquinone, and Polyacrylonitrile-were tested and the MIE data were compared with those taken with a conventional apparatus(the Hartmann tube). Two of them agreed satisfactory, but the other, anthraquinone, showed quite different values supposedly due to the agglomeration of the powder particles by static-charge.

• 한국추진공학회지
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• 제18권1호
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• pp.26-32
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• 2014

본 연구에서 고에너지 금속 알루미늄의 효과적인 점화를 위해 개발한 직류 방식의 스팀 플라즈마 점화기 가스온도를 OH radical의 방출 스펙트럼을 사용하여 측정하였다. 플라즈마 제트온도는 초고온이므로 비접촉식 광학 계측 방법인 볼츠만 기울기법과 스펙트럼 비교 분석법을 이용하여 측정하였으며 각각의 방법은 정밀하게 검증 후 실험에 적용되었다. 플라즈마 점화기의 노즐 팁으로부터 30 mm 범위에서의 제트온도 측정결과 두 방법 모두 알루미늄의 점화온도(${\approx}2400K$) 이상의 2900 K ~ 5800 K를 확인할 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.353-358
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• 2008

현재 인하 로케트 연구회에서는 소형 로켓 모터 점화를 위해 흑색화약 및 PVA수지를 혼합하여 점화기를 제작하고 있다. 하지만 제작 과정의 모호함으로 인해 그 성능이 일정하지 않아, 점화기로서 부족한 점으로 지적되고 있다. 따라서 흑색화약 및 PVA수지의 혼합비에 따른 연소 특성을 파악하여 추진제 점화기 요구 조건 충족 조건을 실험적으로 확인하였다. 특히 추진제 점화기의 요구 조건인 추진제 점화 온도 및 안정 연소 압력 조성에 대하여 중점적으로 다루었으며, 산화제와 연소 촉매의 비율에 따른 연소 가스의 온도 및 압력 변화를 통해 그 경향성을 알 수 있었다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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• pp.241-243
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• 2012

Experiments were conducted to get the design concepts for the continuous aluminum particle feeding system. Two opposed cylinders were used. Aluminum particles in one cylinder were ejected to the air by the supplying gas and the pressure of the other cylinder. It was not possible to eject more aluminum mass flowrate than that of gas if particles were just thrust by the pressure difference between two cylinders. Aluminum particle/air mixture in the flow system was successfully ignited by the electric spark.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.629-637
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• 2017

식료품 가공 산업에서 분진폭발사고가 자주 발생하고 있으며 배관이나 장치 내의 화염전파에 의한 폭발피해가 증가하고 있다. 그러나 다양한 분체특성으로 인하여 활용 가능한 화재폭발특성자료가 적다는 문제가 있다. 사고발생 빈도가 높고 사회적 수요가 많은 설탕, 옥수수, 밀가루의 발화 위험성과 폭발특성을 실험적으로 조사하였다. 설탕, 옥수수, 밀가루 분진의 평균입경은 27.56, 14.76, $138.5{\mu}m$로 나타났으며 이러한 분체조건에서 열중량분석(TGA) 및 시차주사열량계(DSC)를 사용하여 발화온도를 조사하였다. 최대폭발압력($P_m$) 및 폭발지수는($K_{st}$) 각각 7.6, 7.6, 6.1 bar 및 153, 133, 61 [$m{\cdot}bar/s$]로서 분진폭발 위험성은 설탕이 가장 높고 밀가루가 가장 작았다. 또한 분진폭발 시의 화염전파로 인한 피해확대 위험성을 평가하기 위하여 분진화염전파의 소요시간을 계산하였으며 화염전파로 인한 폭발피해 위험성은 설탕, 밀가루, 옥수수 분진의 순으로 높았다.

• 한국재료학회지
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• 제12권10호
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• pp.784-790
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• 2002

For mass product of nanocrystalline ZnO ultrafine powders, self-sustaining combustion process(SCP) and ultrasonic spray combustion method(USCM) were applied at the same time. Ultrasonic spray gun was attached on top of the vertical type furnace. The droplet was sprayed into reaction zone of the furnace to form SCP which produces spherical shape with soft agglomerate crystalline ZnO particles. To characterize formed particles, fuel and oxidizing agent for SCP were used glycine and zinc nitrate or zinc hydroxide. Respectively, with changing combustion temperature and mixture ratio of oxidizing agent and fuel, the best ultrasonic spray conditions were obtained. To observe ultrasonic spray effect, two types of powder synthesis processes were compared. One was directly sprayed into furnace from the precursor solution (Type A), the other directly was heated on the hot plate without using spray gun (Type B). Powder obtained by type A was porous sponge shape with heavy agglomeration, but powder obtained using type B was finer primary particle size, spherical shape with weak agglomeration and bigger value of specific surface area. 9/ This can be due to much lower reaction temperature of type B at ignition time than type A. Synthesized nanocrystalline ZnO powders at the best ultrasonic spray conditions have primary particle size in range 20~30nm and specific surface area is about 20m$^2$/g.

• 자원리싸이클링
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• 제21권3호
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• pp.21-27
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• 2012

이전의 연구에서는 $Mn_3O_4$ 분진으로부터 고순도 훼로망간를 얻기 위해, Al 테르밋법이 검토되었다. 그 결과는 Mn 함유율이 약 93% 이상이고, KS D3712 규격 이하의 낮은 C, P, S의 불순물을 함유한 고순도 페로망간을 얻을 수 있음 보여주었다. 본 연구에서는 제조 코스트가 Al 분말보다 저렴한 Si 분말이 $Mn_3O_4$ 분진의 테르밋 반응법의 환원제로 검토되었다. 그 결과 환원제로 Si 분말을 단독으로 첨가할 경우는 착화가 불안정하여 테르밋 반응이 일어나지 않았으나, 환원제로 Si 분말과 Al 분말을 동시에 첨가할 경우는 C, P, S의 불순물 함유율이 매우 낮은 고순도 페로망간을 얻을 수 있었다.

• 한국안전학회지
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• 제32권6호
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• pp.16-21
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• 2017

Fire or electrical problem while DC electric traction vehicle operation caused by various reasons can lead to not only suspension of the operation, but also severe aftermath such as massive casualty. In this paper, fire analysis on DC electric traction vehicle caused by electrical breakdown on line breaker, which is in connection with the power supply, is presented. When the electric arc, the by-product of frequent line breaker operation, is not fully diminished, it leads to electrical breakdown and fire. Especially, electrical breakdown can be easily induced by the open-and-close operation of inner contractor inside line breaker, eventually followed by ground fault and generation of transient current. Electric arc is consequent on the ground fault and acts as possible ignition source, leading to fire. Also, during the repetitive operation of the line breaker, the contactor is separated each other and some copper powder is generated, and the copper powder provided breakdown path, resulting in fire.

• Computers and Concrete
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• 제13권3호
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• pp.325-342
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• 2014

The use of lightweight aggregate (LWA) instead of ordinary aggregate may make lightweight aggregate concrete, which possesses many advantages such as lightweight, lower thermal conductivity, and better fire and seismic resistance. Recently the developments of LWA have been focused on using industrial wastes as raw materials to reduce the use of limited natural resources. In view of this, the intent of this study was to apply Taguchi optimization technique in determining process condition for producing synthetic LWA by incorporating waste thin film transition liquid crystal displays (TFT-LCD) glass powder with reservoir sediments. In the study the waste TFT-LCD glass cullet was used as an additive. It was incorporated with reservoir sediments to produce LWA. Taguchi method with an orthogonal array L16(45) and five controllable 4-level factors (i.e., cullet content, preheat temperature, preheat time, sintering temperature, and sintering time) was adopted. Then, in order to optimize the selected parameters, the analysis of variance method was used to explore the effects of the experimental factors on the performances (particle density, water absorption, bloating ratio, and loss of ignition) of the produced LWA. The results showed that it is possible to produce high performance LWA by incorporating waste TFT-LCD glass cullet with reservoir sediments. Moreover, Taguchi method is a promising approach for optimizing process condition of synthetic LWA using recycled glass cullet and reservoir sediments and it significantly reduces the number of tests.

• 한국분말재료학회지
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• 제26권3호
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• pp.220-224
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• 2019

The aluminum (Al)/copper oxide (CuO) complex is known as the most promising material for thermite reactions, releasing a high heat and pressure through ignition or thermal heating. To improve the reaction rate and wettability for handling safety, nanosized primary particles are applied on Al/CuO composite for energetic materials in explosives or propellants. Herein, graphene oxide (GO) is adopted for the Al/CuO composites as the functional supporting materials, preventing a phase-separation between solvent and composites, leading to a significantly enhanced reactivity. The characterizations of Al/CuO decorated on GO(Al/CuO/GO) are performed through scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy mapping analysis. Moreover, the functional bridging between Al/CuO and GO is suggested by identifying the chemical bonding with GO in X-ray photoelectron spectroscopy analysis. The reactivity of Al/CuO/GO composites is evaluated by comparing the maximum pressure and rate of the pressure increase of Al/CuO and Al/CuO/GO. The composites with a specific concentration of GO (10 wt%) demonstrate a well-dispersed mixture in hexane solution without phase separation.