• 한국의류학회지
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• 제36권2호
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• pp.179-193
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• 2012

The development of modern transportation technology has required many people in spaces (such as vehicle seats, airports, and train stations) for long periods. The public seats provided in these places are manufactured in a standard size; however, fatigue sets in if the seats are unsuitable for the person's physical size. For this reason, this study developed an air cushion vest that would enhance the comfort of vehicle seats. Passengers in vehicles, trains, airplanes, and buses were observed and surveyed to understand the demand for seat comfort. Our analysis found that the greatest source of discomfort was involuntary nodding of the head while asleep and discomfort around the waist area. For this reason, the air cushion vest was designed to support the head and the waist. The neck cushion of this vest was designed to strengthen head support to counter forward nodding because existing commercial neck cushions had no support for forward nodding. For the waist cushion, at lumbar and below-lumbar parts were chosen as the key parts to be supported, the cushion was designed to contain air at those parts. To cover the embedded waist cushion, the vest was designed to be long. The closure was constructed with zippers from the neck to waistline, and with invisible snaps from the waistline to the hemline so that the wearer could open them easily while seated. A subjective comfort evaluation was conducted to verify the effectiveness of the developed vest. In the test, the developed cushions received a better evaluation than cushions currently available on the market. The volume of the vest could be adjusted by the inflow and outflow of air. It was proven that the vest was effective in terms of comfort and portability. This shows that the developed vest could enhance passenger comfort while sitting on vehicle seats.

• 대기
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• 제17권1호
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• pp.109-114
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• 2007

The mist on the inside of an automobile windshield is not only uncomfortable but also very dangerous because it obstructs the driver's vision. However, the removal process of the mist has never been studied in detail. This study performed experiments analyzing the mechanism causes the mist in a car and investigated the appropriate removal process. The experiments were performed on two rainy days, 10 April 2006 and 26 May 2006, with temperature and relative humidity sensors of testo-175-H2 and DICKSON-TK500. We found a passenger increased water vapor by 0.2 g $min^{-1}$ through respiration and thereby relative humidity (RH) from 55% to 67% in 8 minutes. Even though RH was not saturated, misting occurred because the humid air contacted the colder surface of the window. To remove the mist, it is necessary to increase the temperature or inflow drier air in the car. Therefore, we expected that the heater would be more effective than air conditioner for this matter. However, the outcome was the other way around due to the structure of the heating and cooling system in the car. When the air-conditioner was on, colder and drier air was generated and flowed through the so-called evaporator. Droplets were produced in the evaporator due to cooling procedure. When the heater was on, the warm air evaporated the droplets and increased the water content in the air resulting in an increase of relative humidity. Consequently, the air conditioner is more effective than the heater to remove the mist.

• 한국분말재료학회지
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• 제27권2호
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• pp.139-145
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• 2020

The powder manufacturing process using the gas atomizer process is easy for mass production, has a fine powder particle size, and has excellent mechanical properties compared to the existing casting process, so it can be applied to various industries such as automobiles, electronic devices, aviation, and 3D printers. In this study, a modified A4032-xSn (x = 0, 1, 3, 5, and 10 wt.%) alloy with low melting point properties is investigated. After maintaining an argon (Ar) gas atmosphere, the main crucible is tilted; containing molten metal at 1,000℃ by melting the master alloy at a high frequency, and Ar gas is sprayed at 10 bar gas pressure after the molten metal inflow to the tundish crucible, which is maintained at 800℃. The manufactured powder is measured using a particle size analyzer, and FESEM is used to observe the shape and surface of the alloy powder. DSC is performed to investigate the change in shape, according to the melting point and temperature change. The microstructure of added tin (Sn) was observed by heat treatment at 575℃ for 10 min. As the content of Sn increased, the volume fraction increased to 1.1, 3.1, 6.4, and 10.9%.

• 한국입자에어로졸학회지
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• 제15권4호
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• pp.139-148
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• 2019

This study was performed for the application of a high-speed centrifugal cyclone to shale gas mining process. This device uses the centrifugal force to control particles similar to typical cyclones, and the disk located inside the cyclone is forced to rotate using a motor. The pressure difference occurred during the rotating of disk. Hence, inflow rate was generated without a blower fan. In addition, flow rate increased with elevating rpm of motor. The installing the disk in multiple stages on the inner rotor increased the instantaneous disk outlet flow. Hence, the control efficiency of oil particle increased from 1.05% to 31.2%. By modifying the structure of the disk so that the air flow to the opposite direction of the cyclone, the control efficiency of oil particles increased to 81.5%. By increasing the capacity of the motor and the size of the disk, the flow rate was increased to 2.5 ㎥/min because the rpm of motor and pressure difference increased. As rpm of motor increased, the cut-off diameter (d_pc) became smaller. Unlike the Lapple's equation, d_pc was inversely proportional to the effective number of rotations (N_e). The control efficiency was maintained even if the concentration of oil particles increased, for this reason, the higher the oil concentration, the more particles were accumulated and controlled.

• 대기
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• 제21권2호
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• pp.185-196
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• 2011

The performance assessment in radiosonde observation on the special observation program (ProbeX-2009) is performed and the characteristics of precipitation using Auto Weather System (AWS) and radiosonde data in 2009 at the Ulleungdo are investigated. The launching time, observation time, and maximum altitude of radiosonde are satisfied with the regulation from Korea Meteorological Administration (KMA) and World Meteorological Organization (WMO) but the duration of observational time of radiosonde is much shorter than that of the ProbeX-2007 because the altitude of launching site is higher than others in 2007. From the analysis of trajectories of radiosonde, most radiosondes at the Ulleungdo tend to move into the east because the westerly prevail at the middle latitude. However, when the Okhotsk high is expanded to the Korean peninsula and the north-westerly winds strengthen over the East Sea as the subtropical high is retreated, radiosonde tends to move into the south-west and south-east, respectively. Maximum distance appears at the end of observation level before May but the level of maximum distance is changed into 100 hPa after June because the prevailing wind direction is reversed from westerly to easterly at the stratosphere during summer time. The condition of precipitation was more correlated with the dynamic instability except Changma season. Precipitation in 2009 at the Ulleungdo occurred under the marine climate so that total precipitation amounts and precipitation intensity were increased and intensified during nighttime. The local environment favorable for the precipitation during nighttime was while the wind speed at the surface and the inflow from the shoreline were strengthened. Precipitation events also affected by synoptic condition but the localized effect induced by topography was more strengthened at the northern part of Ulleungdo.

• 한국지리정보학회지
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• 제16권2호
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• pp.16-29
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• 2013

본 연구는 경상남도 창원시를 대상으로 MetPhoMod 모델링의 야간시간대 바람패턴결과를 이용하여 공기순환성 평가를 실시하였다. 공기순환성 평가는 바람의 지속성과 교란성의 평가지수를 이용하여 분석하였으며, 바람의 지속성은 바람패턴의 풍속, 바람의 교란성은 풍향의 다양성 결과를 활용하였다. 분석결과 도시지역 중 공기순환성이 취약한 지역은 봉림동, 용지동, 반송동 등으로 나타났으며, 특히 용지동과 상남동, 사파동의 고층아파트 및 상업지역, 단독주거지역에서 바람정체현상이 발생하는 것으로 확인되었다. 따라서 이러한 공기순환성이 취약하여 바람정체현상이 발생하는 지역에 대해 공간개선을 함으로써 바람의 유동이 원활할 수 있도록 조성되어야 할 것이며, 도시외곽에서 생성되는 바람이 지속적으로 유입될 수 있도록 개발계획차원에서 바람길 조성방안이 마련되어야 할 것으로 판단된다.

• 한국지반신소재학회논문집
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• 제12권2호
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• pp.35-42
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• 2013

흙 구조물의 안정성은 물과 직접적인 관련이 있고, 강우나 침투수에 대한 충분한 대책을 세우지 않는다면 구조물에 큰 피해를 입을 수 있다. 최근 이상기후로 인한 집중호우의 횟수가 잦아짐에 따라 흙 구조물의 안정성에 대한 관심이 커지고 있으며, 구조물의 배수에 대한 여러 가지 방법이 제시되고 있다. 본 연구에서는 연직 배수공법에 사용되는 PBD(Plastic Board Drain)를 보강토 옹벽의 수평 배수재로 이용했을 시 적용성 여부에 대해 평가 하였다. 특히 전면벽을 콘크리트 블록이 아닌 토낭으로 하여 시공성과 경제성을 높이고, 토낭과 연결재, PBD를 일체화 시켜 안정성을 확보하였다. PBD를 활용한 배면수의 투수능 시험결과 보강토체 사이에 자갈층을 포설한 것과 유사한 효과를 나타내었으며, 실제 현장에서의 수평배수재로 활용이 가능한 것으로 판단된다.

• KIEAE Journal
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• 제6권2호
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• pp.43-50
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• 2006

A Double Facade System(DFS) is well known as an innovative solution of ecological facade in the west european countries. There are more than 200 various realized DFS in Germany. At the same time, the korean engineers have researched to find out the physical advantages of DFS in the moderate korean climate, which has a very humid summer with high temperature and a dry winter with low temperature. For example, the monthly mean temperature in Korea comes up to 28K, while that in Germany comes up to only 19K. That is, why a other solution of DFS is needed in Korea. This study has experimented the physical performance of the natural ventilation in the heating period. The preheating function of the cold air by DFS can improve no doubt the performance of the natural ventilation at the cold season as well as spring and autumn. The physical difference between single and double facade on natural ventilation has been tested at the newly constructed laboratory, which can turn $360^{\circ}$ to confirm the characteristic of a facade with the various directions. The results show the natural ventilation of the DFS has definitely much more comfortable than that of the single facade system. The air velocity of the inflow as well as the air temperature in the DFS provide a more stable condition than in the SFS. The theoretical limit(air velocity max 0.2m/s, air temperature min. $18^{\circ}C$, temperature difference between 100mm and 1700mm height max. 3K) on the indoor comfortableness doesn't go over in the DFS. On the other hand, the SFS showed an unstable condition with an excess of comfortableness limit on air velocity as well as temperature. In view of the researching results so far achieved, the research came to a conclusion, that the DFS can provide a more comfortable indoor condition by the preheating in the heating period than a SFS, and the period of natural ventilation in winter time could be definitely increased at the DFS.

• 한국항해항만학회지
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• 제33권3호
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• pp.175-180
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• 2009

본 연구에서는 슈퍼요트의 쾌적한 실내환경조성을 목적으로 기초자료를 수집하였으며, 요트가 주로 운항되는 여름철 실내공간에 형성되는 실내환경성능에 대해 실측을 통해 분석함으로써 다음과 같은 결과를 얻었다. 1) 외부와 연결된 살롱의 문을 닫을 경우 선박배기가스의 실내유입은 거의 없으나 문을 여는 경우에는 급속히 실내공기가 오염되므로 쾌적한 실내공기환경을 유지하기 위해 실내환기방법 및 환기량에 대한 대책이 필요하다. 2) 운항 시에는 모든 실이 선원보호 소음규제치인 60dB을 넘고 있어 실내의 소음대책이 시급하다. 3) State cabin과 Guest cabin은 에어컨가동에 의해 과냉됨으로써 실내 환경이 쾌적범위를 벗어나고 있어 이에 대한 대책이 필요하다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.87-87
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• 2017

최근 이상기후로 인해 국내 가뭄피해가 증가하고 있는 추세이며, 미래 가뭄의 심도 및 지속시간은 증가할 것으로 예측되고 있다. 특히 우리나라는 용수공급의 56.5%를 댐에 의존하여 댐 유역의 가뭄은 생 공 농업용수 공급제한 등의 광범위한 피해를 발생시킬 수 있다. 다만 가뭄은 홍수와 달리 진행속도가 비교적 느리기 때문에 사전에 정확한 댐 유입량 예측이 가능하다면, 용수공급량 조정을 통해 피해를 최소화할 수 있다. 국내에서는 댐 유입량 예측에 ESP (Ensemble Streamflow Prediction) 기법을 활용하고 있으며, ESP 기법은 과거 기상자료를 기반으로 미래를 예측하기 때문에 기상자료, 초기수문조건, 매개변수 등에 불확실성을 가지고 있다. 본 연구에서는 베이지안 이론을 이용하여 댐 예측유입량의 정확도 향상기법을 개발하고 예측성을 평가하고자 하며, 강우유출모델은 ABCD를 활용하였다. 대상유역은 국내의 대표 다목적댐인 충주댐 유역을 선정하였으며, 기상자료는 기상청, 국토교통부 및 한국수자원공사의 지점자료를 수집하였다. 예측성 평가기법으로는 도시적 분석방법인 시계열 분석, 통계적 분석방법인 Skill Score (SS)를 활용하였다. 시계열 분석 결과 ESP 댐 예측유입량(ESP)은 매년 월별 전망값의 큰 차이가 없었으며, 다우년 및 과우년의 예측성이 떨어지는 것으로 나타났다. 베이지안 기반의 댐 예측유입량(BAYES-ESP)는 ESP의 과소모의하는 경향을 보정하였으며, 다우년에 예측성이 향상되었다. 월별 평균 댐 관측유입량과 ESP, BAYES-ESP의 SS 비교분석 결과 ESP는 유입량 값이 적은 1, 2, 3월에 SS가 양의 값을 가졌으며, 이외의 월에는 음의 값으로 나타났다. BAYES-ESP는 ESP와 관측값이 비교적 선형관계를 나타내는 1, 2, 3월에 ESP의 예측성을 개선시키는 것으로 나타났다. ESP 기법은 강수량의 월별, 계절별 변동성이 큰 우리나라에 적용하기에는 예측성의 한계가 있었으며, 이를 개선한 BAYES-ESP 기법은 댐 유입량 예측 연구에 가치가 있는 것으로 판단된다.