• 한국추진공학회지
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• 제5권2호
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• pp.1-7
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• 2001

매우 높은 연소가스로부터 연소실을 보호하기 위하여 액체로켓에서는 재생냉각방법을 폭넓게 이용하고 있다. 재생냉각을 통한 로켓엔진의 냉각을 매우 효과적인 방법이지만, 이를 개발하기 위해서는 정확한 해석과정, 제작기술 등이 필요하다. 한다. 실제 소형 로켓엔진에 재생냉각을 이용한 엔진 냉각의 가능성을 확인하기 위하여 설계, 제작된 로켓으로 연소실험을 진행하였다. 실험에 사용한 연소실은 coolant passage 3 mm, 벽 두께 1 mm, stainless 304로 제작하였다. 최대연소압과 연소시간은 각각 400 psi와 60 sec이고, coolant 유량은 2 kg/s에서 0.12 kg/s까지 감소시키면서 실험하였다. 연소시험후 육안으로 검사한 결과 연소실에서 특별한 이상은 발견되지 않았다.

• 한국항공우주학회지
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• 제32권10호
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• pp.102-111
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• 2004

본 논문에서는 와류분사기를 가진 액체로켓엔진용 축소형 연소기의 설계/제작/시험에 대해 기술하였다. 와류분사기는 내부에 액체산소 외부에 케로신을 공급하여 노즐 외부에서 혼합하는 구조를 가지고 있다. 축소형 연소기는 분사기 헤드, 삭마 냉각방식의 내열재 연소실 그리고 물냉각 노즐로 구성되어 있다. 분사기 헤드는 18 개의 주 분사기, 하나의 중앙 분사기, 연료 메니폴드, 산화제 메니폴드 그리고 추진제 분배기 등으로 구성되어 있다. 축소형 연소기 제작 후 수류시험 및 점화시험을 거쳐 설계점 및 탈설계점에서의 연소시험을 성공적으로 수행하였다. 연소시험결과 분사기 차압은 수류시험시의 값과 비슷하였고 연소효율은 목표치보다 높게 나왔으며, 정상연소시 동압의 진폭은 규격조건을 만족하였고 고주파 연소 불안정은 발생하지 않았다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.102-108
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• 2009

Fossil power plants firing lower grade coals or equipped with modified system for NOx controls are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases significant derate, availability losses and increase in unburned carbon levels can be attributed to poor combustion conditions as a result of poorly controlled local fuel and air distribution within the boiler furnace. In order to develop a on-line combustion tuning system, field test was conducted at operating power boiler. During the field test the exhaust gases' $O_2$, NOx and CO was monitored by using a spatially distributed monitoring grid located in the boiler's high temperature vestibule and upper convective back-pass region. At these locations, the flue gas flow is still significantly stratified, and air in-leakage is minimal which enables tracing of poor combustion zones to specific burners and over-fire air ports. using these monitored information we can improving combustion at every point within the furnace, therefore the boiler can operate at reduced excess $O_2$ and gas temperature deviation, reduced furnace exit gas temperature levels while also reducing localized hot spots, corrosive gas conditions, slag or clinker formation and UBC. Benefits include improving efficiency, reducing NOx emissions, increasing output and maximizing availability. Discussion concerning the reduction of greenhouse gases is prevalent in the world. When taking a practical approach to addressing this problem, the best way and short-term solution to reduce greenhouse gases on coal-fired power plants is to improve efficiency. From this point of view the real time optimized combustion tuning approach is the most effective and implemented with minimal cost.

• 한국태양에너지학회 논문집
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• 제29권5호
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• pp.45-52
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• 2009

Fossil power plants firing lower grade coals or equipped with modified system for $NO_x$ controls are challenged with maintaining good combustion conditions while maximizing generation and minimizing emissions. In many cases significant derate, availability losses and increase in unburned carbon levels can be attributed to poor combustion conditions as a result of poorly controlled local fuel and air distribution within the boiler furnace. In order to develop a on-line combustion tuning system, field test was conducted at operating power boiler. During the field test the exhaust gases' $O_2,\;NO_x$ and CO was monitored by using a spatially distributed monitoring grid located in the boiler's high temperature vestibule and upper convective rear pass region. At these locations, the flue gas flow is still significantly stratified, and air in-leakage is minimal which enables tracing of poor combustion zones to specific burners and over-fire air ports. using these monitored information we can improving combustion at every point within the furnace, therefore the boiler can operate at reduced excess $O_2$ and gas temperature deviation, reduced furnace exit gas temperature levels while also reducing localized hot spots, corrosive gas conditions, slag or clinker formation and UBC. Benefits include improving efficiency, reducing $NO_x$ emissions, increasing output and maximizing availability. Discussion concerning the reduction of greenhouse gases is prevalent in the world. When taking a practical approach to addressing this problem, the best way and short-term solution to reduce greenhouse gases on coal-fired power plants is to improve efficiency. From this point of view the real time optimized combustion tuning approach is the most effective and implemented with minimal cost.

• Safety and Health at Work
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• 제8권4호
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• pp.386-392
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• 2017

Background: Fire service workers often implement multiple duties in the emergency conditions, with such duties being mostly conducted in various ambient temperatures. Methods: The aim of the current study was to assess the firefighters' physiological responses, information processing, and working memory prior to and following simulated firefighting activities in three different hot environments. Seventeen healthy male firefighters performed simulated firefighting tasks in three separate conditions, namely (1) low heat (LH; $29-31^{\circ}C$, 55-60% relative humidity), (2) moderate heat (MH; $32-34^{\circ}C$, 55-60% relative humidity), and (3) severe heat (SH; $35-37^{\circ}C$, 55-60% relative humidity). It took about 45-50 minutes for each firefighter to finish all defined firefighting activities and the paced auditory serial addition test (PASAT). Results: At the end of all the three experimental conditions, heart rate (HR) and tympanic temperature (TT) increased, while PASAT scores as a measure of information processing performance decreased relative to baseline. HR and TT were significantly higher at the end of the experiment in the SH ($159.41{\pm}4.25beats/min$; $38.22{\pm}0.10^{\circ}C$) compared with the MH ($156.59{\pm}3.77beats/min$; $38.20{\pm}0.10^{\circ}C$) and LH ($154.24{\pm}4.67beats/min$; $38.17{\pm}0.10^{\circ}C$) conditions (p < 0.05). There was no significant difference in PASAT scores between LH and MH (p > 0.05). Nonetheless, there was a measurable difference in PASAT scores between LH and SH (p < 0.05). Conclusion: These consequences demonstrate that ambient temperature is effective in raising the physiological responses following firefighting activities. It is therefore argued that further increase of ambient temperature can impact firefighters' information processing and working memory during firefighting activity.

• Journal of the Korean Wood Science and Technology
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• 제12권2호
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• pp.20-26
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• 1984

내화처리(耐火處理)된 합판(合板)의 내부(內部)에 잔존(殘存)하고 있는 내화약제(耐火藥劑)의 종류(種類) 및 그 양(量)이 합판(合板) 특유(特有)의 장점(長點)인 휨 강도(强度)에 어떠한 영향(影響)을 미치는 가를 조사(調査)하기 위(爲)해 황산(黃酸) 암모늄(Ammonium sulfate), 제1인산(第一燐酸) 암모늄(Ammonium phosphate, mono basic), 제2인산(第二燐酸) 암모늄(Ammonium phosphate, di basic), 그리고 복합약제(複合藥劑)인 붕사(硼砂) 붕산(硼酸)(Borax-Boric acid) 및 미나리스(Minalith) 등(等) 5종(種)의 내화제(耐火劑)를 20% 수용액(水溶液)으로 조제(調劑)한 다음 3.5mm 메란티 합판(合板)을 3시간(時間)부터 12시간(時間) 동안 3시간(時間) 간격(間隔)으로 침지처리(浸漬處理)를 한 후(後) $120^{\circ}C$의 열판(熱板)으로 재건조(再乾燥)하여 휨 강도시험(强度試驗)을 행(行)하였다. 비례한계(比例限界)에서의 응력(應力), 탄성계수(彈性係數), 파괴계수(破壞係數) 및 비례한계(比例限界)까지의 단위체적(單位體積) 당(當) 일등(等)을 조사(調査)한 바, 약제처리(藥劑處理)한 합판(合板)의 경우가 수분처리합판(水分處理合板)(대희구(對熙區))에 비(比)해 대부분(大部分) 높게 나타났으며 붕사(硼砂) 붕산(硼酸) 처리합판(處理合板)의 경우가 4부간(部間)에서 공(共)히 가장 높은 치(値)를 보여주었다. 그리고 처리시간(處理時間)이 연장(延長)됨에 따라, 즉 약액(藥液)의 흡수량(吸收量)(약제(藥劑) 잔존량(殘存量))이 증가(增加)함에 따라 휨 강도(强度)는 대체적(大體的)으로 향상(向上)하는 것으로 나타났다. 강도적(强度的) 측면(側面)이나 침지처리시(浸漬處理時) 발생(發生)하는 결함(缺陷) 등을 고려(考慮)할 때 복합약제(複合藥劑)인 붕사(硼砂) 붕산(硼酸)이 가장 바람직한 합판용(合板用) 내화처리약제(耐火處理藥劑)로 사료되는 바이다.

• 수산해양기술연구
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• 제49권2호
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• pp.116-125
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• 2013

Jigging and angling fishery is prevalent in the East Sea of Korea and this fishery needs many lamps to attract the fish. And the fishing boat uses 24~47 ballasts by the vessel's tonnage to turn on the fishing lamp. A 3.5kW magnetic-type ballast being currently used at many fishing boats can drive two 1.5kW metal-halide lamps. Meanwhile, this ballast has large weight (25kg) and volume. Therefore it is one of reason for the over-consumption of energy and the fire, resulted from overheat and electrical short, occurs occasionally because the ballast is installed at narrow and hot engine room. In addition, most of magnetic ballast has several problems such as periodic condenser replacement, low energy efficiency and making lamp short life, etc. So it is necessary to improve or develop newly the electronic ballast, which has to be smaller, lighter and more efficient. An electronic ballast was designed for the fishing boat by considering duration and electromagnetic interference in the study. Its weight and volume are respectably 40% and 66% compared to current ballast on the basis of PCB. The metal-halide lamp's spectrum of the designed ballast was nearly same to that of the current ballast in the test of lighting. In particular, the light stability was improved and there isn't any radio interference. As mentioned above, it is expected that the developed electronic ballast can replace current magnetic ballast because of many advantages related to energy-saving.

• 한국주거학회논문집
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• 제20권2호
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• pp.77-86
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• 2009

The purpose of this study was to examine the household characteristics, the actual residential environment of the elderly living with their offsprings together in Gwangju. We also evaluated their satisfaction with the needs for remodeling of their houses and the different opinions about those things between the elderly and their off springs. We used comparative and descriptive T-test in statistical analysis. The results were as follows. There were more families living in the detached houses than those living in the apartments. The average size of the houses was 100.8 square meters. The mean residence period was 13.5 years. The sons were usually the legal householders. The residents who experienced remodeling before reassigned the furniture and installed the bathtub, which was designed to be sat on comfortably in a common. A few residents installed safety system such as alarms for incident fire or gas, convenient knobs for handling and faucets for running hot or cold water separately. After the installation of alarms, convenient knobs of windows or door, Customer satisfaction for those things were quite high. But that for the installation of safety bar were the lowest in contrast. The most things the old wanted to change were to rearrange bedrooms and bathrooms on the first floor and to decorate them in westernized styles. They didn't need to set up safety bars or shower instrument for modulating heights. The second generation wanted to install the blinds or curtains more than the third generations.

• 한국항공우주학회지
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• 제30권8호
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• pp.120-125
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• 2002

KSR-III 축소(I) 기본형 엔진에 대한 연소 시험을 실시한 결과 분사면의 내열 특성이 불량한 것으로 판명되었으며, 이에 기본형 엔진의 설계를 다각도로 수정한 축소(I) 수정형 엔진을 제작하게 되었다. 주요 설계 파라미터는 주분사기의 배열, 주분사기의 충돌각, 열차폐코팅이었으며 이들에 대한 시험적 연구를 수행하고 각 디자인에 대한 엔진 성능 및 내열 성능을 비교하였다. 내열 성능은 직교배열의 경우, 주분사기 충돌각이 작은 경우, 열차폐 코팅이 있는 경우 향상되는 경향을 보였으며, 일부는 30초 시험을 통해서 적절한 내열 성능을 보여주었다. 그에 따른 엔진 성능의 변화를 살펴보면 5% 범위 이내에서 성능 차이를 보이는데, 방사배열의 경우가 직교배열의 경우보다 성능이 높고, 주분사기 충돌각 $15^{\circ}$의 경우가 $20^{\circ}$의 경우보다 오히려 높게 나타났다. 또한, 저주파 연소불안정성의 측면에서는 충돌각이 작을수록, 방사형 배열보다는 직교형 배열의 경우 불안정 특성이 큰 것으로 판명되었다. 이러한 내열 성능 및 엔진 성능의 변화는 분무 특성의 변화 및 이에 의한 화염 구조의 변화에 기인하는 것으로 보이며, 보다 심도 있는 분석을 위해 추가적인 연구가 필요하다.