• 한국환경과학회지
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• 제25권5호
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• pp.705-713
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• 2016

This study investigates the concentration sudden rise in fine particle according to resuspended dust from paved roads after sudden heavy rain in Busan on August 25, 2015. The localized torrential rainfall in Busan area occurred as tropical airmass flow from the south and polar airmass flow from north merged. Orographic effect of Mt. Geumjeong enforced rainfall and it amounted to maximum 80 mm/hr at Dongrae and Geumjeong region in Busan. This heavy rain induced flood and landslide in Busan and the nearby areas. The sudden heavy rain moved soil and gravel from mountainous region, which deposited on paved roads and near roadside. These matters on road suspended by an automobile transit, and increased fine particle concentration of air. In addition outdoor fine particle of high concentration flowed in indoor by shoes, cloths and air circulation.

• 한국압력기기공학회 논문집
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• 제13권1호
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• pp.69-74
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• 2017

In the fire protection system or fire fighting water supply system, the jockey pump is generally installed for the prevention of the pressure decrease of pipes, the frequent driving of the fire pump and protection the pipes from the water hammer. In this paper, the pressure-rise in fire fighting water distribution pipes in condition of pipe pressurization by the surge tank at the start-up and the sudden-stop of the fire pump without additional installation of jockey pump is considered by using simple formula calculations and the evaluation of water hammer occurrence in condition of pipe pressurization by the surge tank is included. As a result, the pressure-rise of pipes is less than the pipe design pressure at the condition of pump's start-up and sudden stop, and the possibility of water hammer occurrence is remarkably low due to pressurization of the pipes by the surge tank.

• Wind and Structures
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• 제16권1호
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• pp.25-46
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• 2013

This paper presents a boundary-layer wind tunnel (BLWT) study on the effect of variable dominant openings on steady and transient responses of wind-induced internal pressure in a low-rise building. The paper presents a parametric study focusing on differences and similarities between transient and steady-state responses, the effects of size and locations of dominant openings and vent openings, and the effects of wind angle of attack. In addition, the necessity of internal volume correction during sudden breaching, i.e., a transient response experiment was investigated. A comparison of the BLWT data with ASCE 7-2010, as well as with limited large-scale data obtained at a 'Wall of Wind' facility, is presented.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.455-456
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• 2008

A numerical study was conducted on the effect of flame holder which could be added to the inlet duct of Integral Rocket-Ramjet. Two different types of flame holder installations, flame holder without sudden expansion region and flame holder with small sudden expansion region, were compared and showed different flame shapes and pressure rise in the combustor.

• 문화기술의 융합
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• 제8권3호
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• pp.99-104
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• 2022

이 연구는 내수면 수난 구조상황에서의 급상승이 코르티솔 및 인체 증상에 미치는 영향을 분석한 것으로 실험 결과는 다음과 같다. 실험대상자는 5명으로 A, B, C는 잠수 전후 코르티솔 상승 수치가 각각 6.30ug/dl, 6.50ug/dl, 6.57ug/dl로 비슷한 수치를 나타내었다. 그런데, 실험대상자 D는 잠수 전후 코르티솔 상승 수치가 11.00ug/dl로 유의하게 높게 나타났다. 그 이유는 수중 시계의 불량으로 인한 불안감 가중 및 급상승 시 긴장을 통한 체력소모 고갈로 판단된다. 실험대상자 E는 잠수 전후 코르티솔 상승 수치가 4.28ug/dl로 유의하게 낮게 나타났는데, 그 이유는 E의 연령이 실험대상자 중 가장 젊고, 해상의 심해 잠수 경험이 풍부하여 불안감이 작아서 나타난 결과로 보인다. 피로도는 7~8, 불안감은 7~9로 둘 다 높은 수치를 나타내었다. 수중수색 시 심리적 긴장감이 피로도를 높이고, 불량한 시계가 불안감을 높인 것으로 사료 된다. 연구 결과는 수난구조대원의 안전한 수중수색 활동에 대한 실증적 자료로 제공될 것이다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2007년도 제34회 KOSCO SYMPOSIUM 논문집
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• pp.114-117
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• 2007

In IRR(Integral Rocket-Ramjet), the booster is integrated into the ramjet combustor. Such combustors do not contain combustor liners or flame holders within the combustor due to the limited volume and flame stabilization depends on the recirculation zones formed by the sudden expansion region between the inlet duct and the combustor. A numerical study was conducted on the effect of flame holder which could be added to the inlet duct of IRR. Two different types of flame holder installations, flame holder without sudden expansion region and flame holder with small sudden expansion region, were compared and showed different flame shapes and pressure rise in the combustor.

• Tribology and Lubricants
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• 제19권5호
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• pp.259-267
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• 2003

A brake device for the high-speed impacting object is designed using an axial crushing of thin-walled metal cylinder. Thickness of the cylinder is increased smoothly from the impacting end to the fixed end, resulting in the truncated cone shape. Truncated cone shape minimizes the imperfection-sensitivity of the structure and ensures that plastic hinges are formed sequentially from impacting end. This prevents the undesirable sudden rise in the first peak-crushing load. Several specimens with different conic angles, mean thickness of the wall, and materials were designed and quasi-static compression tests were performed on them. Results indicate that adoption of appropriate conic angle prevents simultaneous wrinkles generation and sudden rise of crushing load and that appropriate conic angle differs in each case, depending on the geometry and material property of the cylinder. Finite element analysis was performed for static compression of the cylinder and its accuracy was checked for the future application.

• 환경영향평가
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• 제20권4호
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• pp.557-564
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• 2011

This study was conducted to investigate the sudden rise of fine particle concentration after the passage of typhoon USAGI and NARI in Busan. Nocturnal inversion layer was formed at atmospheric boundary layer and wind direction changed from southerly wind to northeasterly wind after USAGI passed through Busan. Fine particle concentration in Busan rapidly increased by subsidence of air pollutants released from sources and dust transported from in the vicinity of industrial regions. Wind direction changed from northeasterly wind to southeasterly wind, wind velocity increased and lower atmosphere became extremely unstable after NARI passed through Busan. $PM_{10}$ concentration of Busan increased sharply because of surface dust dispersed by strong wind. Fine particle concentration generally decreases by precipitation and wind after typhoon passes through. However, the concentration can also go up not only by subsidence and transportation in nocturnal inversion layer but also by surface dust which temporarily occurs by strong wind.

• 국제초고층학회논문집
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• 제7권4호
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• pp.409-415
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• 2018

Recently, many countries around the world began to show interest in safety against terrorism, fire, and natural disasters. This study aimed to propose a quantitative measurement system for emergency evacuation and safety for various kinds of terrorism and fire within high-rise multi-purpose facilities, which can measure the pedestrians' ordinary walking patterns in the concourse with the highest pedestrian volume out of all the spaces within multi-story buildings, predict pedestrians' evacuation walking lines when a sudden disaster breaks out, and analyze the gait coefficient, occupant density, and evacuation behavior time.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.625-627
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• 2005