• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.13-20
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• 2011

In this paper, we proposed a system to raise gas safety management by using the wireless communication module and intelligent gas safety appliances. Our designed systems configure a micom-gas meter, an automatic extinguisher, sensors, and a wallpad. A micom-gas-meter monitors gas flow, gas pressure, and earthquake. An automatic fire extinguisher checks gas(combustible) leaks and temperature of $100^{\circ}C$ and $130^{\circ}C$. Sensors measure smoke and CO gas. In our novel system, a micom-gas meter cut off inner valve with warnings, an automatic fire extinguisher cut off middle valve and spray extinguishing materials, and sensors generate signals for smoke and CO when occurring gas risk. Gas safety appliances and sensors takes safety measures, and transmit those signal to a wallpad. The wallpad again transmit signal like events to a control server. Users can connect web pages for gas safety through B-ISDN and control and manage them. We hereby devised scenarios for gas safety and risk management, and demonstrated their effectiveness through experiments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.6
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• pp.834-840
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• 2018

In this study, the characteristics of air pollutant emissions from ships' engines have been investigated by conducting E2 and E3 cycle mode tests. A engine 360Ps (Doosan L126TIH engine) and 400kW dynamometer Horiba-Schenck were utilized for engine tests. The FTIR analyzer and SPC were used to measure exhaust gas (NOx, SOx etc.) and PM (particulate matter), respectively. The results showed that the emissions of THC and CO produced from engine were increased with the increase of sulfur content in fuel oils at E2 and E3 cycle modes. The kinetic viscosity of the fuel increased as the sulfur content of the fuel increased, thereby the specific fuel oil consumption (SFC) of the engine improved. This result is considered to be due to improved combustion conditions due to increased average diameters of sprayed particles and due to increased kinetic viscosity under constant fuel injection pressure in this study. In the case of NOx emission, this study showed no significant change in amount of sulfur content.

• Fire Science and Engineering
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• v.26 no.2
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• pp.75-83
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• 2012

An experimental study was conducted to investigate the effects of change in heat release rate on unsteady fire characteristics of under-ventilated fire in a semi-closed compartment. A standard doorway width of the full-scale ISO 9705 room was modified to 0.1 m and the flow rate of heptane fuel was increased linearly with time using a spray nozzle located at the center of enclosure. Temperature, heat flux, species concentrations and heat release rate were continuously measured and then global equivalence ratio (GER) concept was adopted to represent the unsteady thermal and chemical characteristics inside the compartment. It was observed that there was a significant difference in unsteady behavior between global and local combustion efficiency, and the GERs predicted by ideal and measured heat release rate were also shown different results in time. The unsteady behaviors of temperature, heat flux and species concentrations were represented well using the GER concept. It was important to note that CO concentration was gradually decreased with the increase in GER after reaching its maximum value in the range of 2.0~3.0 of global equivalence ratio. In addition, the experimental data on unsteady thermal and chemical behaviors obtained in a semi-closed compartment will be usefully used to validate a realistic fire simulation.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.122-122
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• 2014

수중방전을 환경분야에 적용하기 위한 플라즈마 부상법이 개발되었다. 플라즈마 부상법은 물 속에서 발생시킨 플라즈마가 가지고 있는 주요특성 중 물리적 특징인 쇼크웨이브, UV조사, 버블생성 등과 화학적 특징인 OH라디칼 및 염소산화물 생성 등을 이용하여 물 속에 존재하는 용존성 및 입자성 물질을 부상분리 기법으로 제거하는 공법이다. 유기물을 제거하는 기작으로는 침전, 여과, 분해 등이 있고, 이를 구현하기 위한 공정으로 중력침강법, 부상분리법, 멤브레인법, 미생물법 등이 있다. 이 중에서 가압공기부상법은 침강법에 비해 부지면적을 적게 소모하고 처리시간이 50% 이상 감소되는 특징이 있다. 가압공기부상법은 물 속에 공기를 과포화시킨 후 노즐을 통해 재분사할 때 발생하는 압력차에 의해 미세기포가 발생함을 이용하여 유기물을 분리하는 공법이다. 그러나, 가압용 장비 및 반송수가 필요하고, 미생물분리는 불가능한 단점이 있다. 이에 본 연구에서는 미생물살균과 유기물 분리가 동시에 일어나는 플라즈마를 이용한 부상분리기법을 개발하였다. 본 연구에서는 난분해성 용존유기물인 휴믹산 100 mg/L의 플라즈마 공기부상법에 의한 제거능을 확인하였다. 용존성 휴믹산을 입자성 물질로 전환하여 플록을 형성시키고자 알루미늄설페이트(Al2(SO4) $3{\cdot}18H2O$)를 100 mg/L 주입하였고, 침출수와 같이 염도가 높은 물을 모사하고자 35 g/L의 염화나트륨을 첨가한 상태에서 방전을 실시하였다. 방전에 사용된 전원은 EESYS사에서 제작한 펄스형 고전압 전원장치를 사용하였고 최대 15 kW의 출력 중 6 kW의 전력을 인가하였다. 전극 한 개는 2 mm 텅스텐봉을 세라믹튜브로 감싼 구조로 총 사용전극은 28개이다. 전극 한 개당 대략 200 Watt의 전력이 소모되며 이 때 최대의 버블이 생성됨을 확인하였다. 전극 1개에서 생성되는 버블의 부피는 14 mL/min 로 측정되었다. 버블의 크기는 평균 70 um이고 가압공기부상법에서 최적공기크기로 제시하고 있는 40~80 um 의 버블은 약 80% 가량 생성된다. 본 연구에서 사용된 반응시스템에서의 물의 높이는 약 500 mm 이고 전체 40 L의 수조가 3개의 벽으로 분리되어 4개의 수조로 분리되었다. 각 수조는 하부에 7개의 전극을 포함하고 있다. 플라즈마 발생시 생성되는 기포는 약 1분 방전 후에 포화농도에 도달하며 방전종료 후 약 4분간 수체 내에 남아있게 된다. 이를 공정에 적용하여 1분 방전 및 4분 휴지의 순서로 플라즈마를 인가하였다. 휴믹산 용액의 유량을 2 lpm 으로 운전하였을 때 최종 처리율은 94% 이고 이때의 대장균 살균능은 99%이다.

• Korean Journal of Ecology and Environment
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• v.42 no.3
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• pp.404-406
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• 2009

This study note wished to introduce special-purpose ship for algae removal that is developed by core technology of our country. The ship is consisted of main frame and adjuvant that can attach and detach as cross (+) shape of a character. The characteristics of ship are super light weight and low draft. That is consisted of four devices as suction, collection, filtration and recovering units. Among these, filtration used screen filter (mesh size 30 ${\mu}m$). Also, can separate and remove water and algae by compression air participle notion. Percentage of moisture content of concentrated algal particle was 85%. Water parted with algae finally is exhausted to water area. Removal efficiency that compare by chlorophyll-$\alpha$ concentration was about 57% (inflow: 83.2 ${\mu}g\;L^{-1}$, outflow: 35.8 $[\mu}g\;L^{-1}$) without physical and chemical pretreatment. Forward, need to achieve effect test in various conditions (algal biomass, flow etc.) for efficiency and technological elevation of exclusion device. We wished to contribute in presuppression system construction of massive algal development that manage blue-green algae occurrence area effectively, and prevents spread as lower part of reservoir.

• Journal of Korean Medical classics
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• v.13 no.1
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• pp.146-183
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• 2000

통과이상적연구(通過以上的硏究), 장상한학술적성숙기(將傷寒學術的成熟期), 칙지명대여청대관여상한의학사적내용정리(則至明代與淸代關與傷寒醫學史的內容整理) 여하(如下). 1. 명청시대적시대배경사상한학적내용갱풍부(明淸時代的時代背景使傷寒學的內容更豊富), 촉진상한학술적발전(促進傷寒學術的發展) 병차출현료흔다관여상한적저작(幷且出現了?多關與傷寒的著作), 단실제상야출현료상한론내용적중복여지론술일반부분(但實際上也出現了傷寒論內容的重複與只論述一般部分), 혹저자립안조잡적처방지폐단(或著者立案粗雜的處方之弊端). 차기우출현각종상한학파적리유(此期又出現各種傷寒學派的理由), 시인위당시류행적사조(是因爲當時流行的思潮), 칙정주리학적영향여명대문단부고(則程朱理學的影響與明代文壇復古), 의고적추향(擬古的趨向), 환유금원시대적백가쟁오등(還有金元時代的百家爭嗚等), 성료형성상한학파적기초(成了形成傷寒學派的基礎). 2. 위료불실거상한론적본래의식(爲了不失去傷寒論的本來意識), 주장정리화고정원문회부왕숙화이전모양적착간중정파시왕안도기료개단(主張整理和考訂原文恢復王叔和以前模樣的錯簡重訂派是王安道起了開端), 방유집확대료기의식(方有執擴大了其意識). 유창여침명종시대표저학파학자(喩昌與沈明宗是代表這學派學者), 장로(張?) 정응모(程應?) 주양준(周揚俊) 오겸등수료저학설(吳謙等隨了這學說). 3. 주장(主張)'존왕(尊王)(숙화(叔和))찬성(贊成)(무기(无己))'적유호구론파(的維護舊論派), 주장료불능수변개상한론삼음삼양편적배렬여순서(主張了不能隨變改傷寒論三陰三陽篇的排列與順序), 문자(文字), 구문(句文), 문장(文章), 고세식(高世?), 진념조등인(陳念祖等人). 4. 주장상한론적정수재어변증론치(主張傷寒論的精髓在於辨證論治), 선우운용칙능득상한핵심리론적학파시변증론치학파(善于運用則能得傷寒核心理論的學派是辨證論治學派). 저학파분사개계통(這學派分四?系統), 이처방수집증상적의가유허굉(以處方收集證狀的醫家有許宏), 가금(柯琴), 서대춘(徐大椿); 이치법수집증상적의가유오인구(以治法收集證狀的醫家有吳人駒), 우이(尤怡); 이분유륙경찰증상적의가유진념조(以分有六經察證狀的醫家有陳念祖), 포성(包誠); 이증상분류증후적의가유류순(以證狀分類證候的醫家有劉純), 왕긍당(王肯堂), 진지정(秦之楨), 침금오등인(沈金鰲等人). 5. 회통파유량종류형(?通派有兩種類型), 일시수통상한여온병적학파(一是誰通傷寒與溫病的學派), 간칭회통파(簡稱?通派), 대표의가유도화(代表醫家有陶華), 오정(吳貞), 유근초등인(兪根初等人), 령일개유회통중의여서의적립장상해석상한적의가당종해(?一?有?通中醫與西醫的立場上解釋傷寒的醫家唐宗海). 6. 경전학파시이상한론위보귀적경전래인식(經典學派是以傷寒論爲保貴的經典來認識), 병차지유숭상차경여사상적학파(幷且持有崇尙此經與思想的學派), 차리분량개편우원문적고증래연구적경전고증파(此里分兩?偏于原文的考證來硏究的經典考證派), 화인위지유상한론(和認爲只有傷寒論), 재능총괄치료외감병(才能總括治療外感病), 부정온병학설병배척적경전림상파(否定溫病學說幷排斥的經典臨床派).

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.2
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• pp.153-170
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• 2022

Waterjet has been comprehensively used in urban areas owing to a suitable technique for cutting concrete and rock, and low noise and vibration. Recently, the abrasive waterjet technique has been adopted and applied by the Korea Atomic Energy Research Institute to demolish concrete plugging without disturbing and damaging In-situ Demonstration of Engineered Barrier System in the disposal research tunnel. In this study, the use of abrasive waterjet in the tunnel was evaluated for practical applicability and the existing cutting model was compared with the experimental results. As a variable for waterjet cutting, multi-cutting, water flow rate, abrasive flow rate, and standoff distance were selected for the diversity of analysis. As regarding the practical application, the waterjet facilitated path selection for cutting the concrete plugging and prevented additional disturbances in the periphery. The pump's noise at idling was 64.9 dB which is satisfied with the noise regulatory standard, but it exceeded the standard at ejection to air and target concrete because the experiment was performed in the tunnel space. The experimental result showed that the error between the predicted and measured cutting volume was 12~13% for the first cut and 16% for second cut. The standoff distance had a significant influence on the cutting depth and width, and the error tended to decrease with decrement of standoff distance.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.37-44
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• 2022

In this study, two low-swirl nozzles with the same SN (Swirl Number) but different mass ratio (m) of the core part and the swirler part were designed to perform an atmospheric pressure combustion test. For each nozzle, a combustion test was conducted according to the adiabatic flame temperature, and the flame structure, emissions, and combustion instability mode were identified. Although the flame structure was significantly different, the CO emission was similar, and the NOx emission was also more related to combustion dynamics than the flame structure. Combustion dynamics and NOx emission were identified while adjusting the convection delay time by changing the position of the fuel injection nozzle. It was confirmed that when the convection delay time is in the region of (3+4n)/4T±1/4T (n=0,1,2,...), the combustion instability is strong, and in the opposite case, the combustion instability is very weak.

• Korean Journal of Environmental Agriculture
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• v.34 no.2
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• pp.134-138
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• 2015

BACKGROUND: In recent years, several researchers have focused on odour control methods to remove the harmful chemicals from chemical accidents and incidents. The present work deals with the system development of the hazardous. METHODS AND RESULTS: For on-site removal of hazardous gaseous materials from chemical accidents, mobile vortex wet scrubber was designed with water vortex process to absorb the gas into the water. The efficiency of the mobile vortex wet scrubber was evaluated using water spray and 25% ammonia solution. The inlet air velocity (gas flow rate) was according to the damper angle installed within the hood and with increase of gas flow rate, consequently the absorption efficiency was markedly decreased. In particular, when 25% ammonia solution was exposed to the hood inlet for 30 min, the water pH within the scrubber was changed from 7 to 12. Interestingly, although the removal efficiency of ammonia gas exhibited approximately 80% for 5 min, its efficiency in 10 min showed the greatest decrease with 18%. Therefore, our results suggest that the ammonia gas may be absorbed with the driving force of scrubbing water in water vortex process of this scrubber. CONCLUSION: When chemical accidents are occurred, the designed compact scrubber may be utilized as effective tool regarding removal of ammonia gas and other volatile organic compounds in the scene of an accident.