• Title/Summary/Keyword: air cut

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3D Stereoscopic Terrain Extraction of Road Cut Failure Slope Using Unmanned Helicopter Photography System (무인 헬리콥터 사진촬영시스템을 이용한 도로 절개지 붕괴사면 3차원 입체 지형 추출)

  • Jang, Ho-Sik
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.28 no.5
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    • pp.485-491
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    • 2010
  • Acquisition of information on failure slope, which may cause apprehension of second hand damage, requires acquisition of fast and accurate topographical data and efficient expression in indirect surveying method without accessing as needed. Therefore, in this study, the images on the intended area were photographed through hovering in the air by approaching collapsed road cut slope with the use of unmanned helicopter photography system. As a result of comparing the points observed by no prism total station and the 10 coordinate points analyzed through image analysis, the averages of absolute values were shown to be 0.056m in X axis direction, 0.082m in Y axis direction and 0.066m Z axis direction. In addition, the RMSE of the error for 10 points of test points were 0.015636m in X axis direction, 0.021319m in Y axis direction and 0.018734m in Z axis direction. Therefore, this method can determine the range of slope and longitudinal and cross sections of each slope in dangerous area that cannot be approached in relational image matching method for the terrains of such collapsed cut slope.

A Study on Estimation of Air Pollutants Emission from Residential Wood Stove (주거용 화목난로의 대기오염 배출량 추정에 관한 연구)

  • Kim, Pil-Su;Jang, Young-Kee;Kim, Jeong;Shin, Yong-Il;Kim, Jeong-Soo;An, Jun-Young
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.3
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    • pp.276-285
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    • 2010
  • Recently the Korean government has tried to cut down the $PM_{10}$ concentration by the Special Law for Air Quality Improvement. But the concentrations of $PM_{10}$ have exceeded the air quality standard at most monitoring stations. Primary $PM_{10}$ emitted from various sources and emission data have large uncertainty. The biomass burning is one of the major sources of $PM_{10}$ emission. The biomass burning is composed of wood stove usage, meat cooking and agricultural combustion etc.. Activity data and emission factors for the biomass burning are limited, and it is hard to calculate the air pollution emissions from these sources. In this study, we tried to estimate the air pollution emission from residential wood stove usage. The number of total wood stoves is estimated by the survey of wood stove manufacturer. And air pollution emission factors for the wood stove are investigated using the flue gas measurement by U.S. EPA particulate test method (Method 5G). As the results, the $PM_{10}$ and CO emission factors of wood stove are estimated as 7.7 g/kg-wood and 78.8 g/kg-wood respectively. The annual $PM_{10}$ and CO emissions from wood stove are calculated as 1,200~3,600 ton/year and 12,600~36,400 ton/year in Korea. It is confirmed that wood stove is the one of major sources of biomass burning, and the survey for activity data and the measurement for emission factors are needed for reducing the uncertainty of these emission data.

A Study on the Design for the Air Impeller of a Finishing Tool Unit (피니싱 툴 유니트의 에어 임펠러 설계에 관한 연구)

  • Choi, Hyun-Jin;Kang, Ik-Soo;Lee, Seung-Yong;Jang, Eun-Sil;Park, Sun-Myung;Choi, Seong-Dae
    • Korean Journal of Computational Design and Engineering
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    • v.20 no.3
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    • pp.312-319
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    • 2015
  • The grinding and furbishing process as the finishing process for molds include the works such as the grinding, buffing, lapping and polishing among others. A finishing tool unit is applied to this finishing process for the burr, lapping, polishing and others of molds. A finishing tool unit can carry out the flexible machining, depending on the machining allowance for objects to be cut on the basis of the instrumental driving mechanism which enables the up, down, left and right floating, which is applied in link with the dedicated cutters and robot machining systems. This study selected the shape to increase the rotatory force of an impeller when air is discharged during the driving of a finishing tool unit, and reflected it to the impeller designing. In addition, the study analyzed each flow velocity and pressure distribution per air pressurization value and finally analyzed the rotating torque to suggest the optimal conditions in designing impellers.

Acetone PLIF for Fuel Distribution Measurements in Liquid Phase LPG Injection Engine (LPG 액상분사 엔진에서 아세톤 PLIF를 이용한 연료분포 측정기법 연구)

  • 오승묵;박승재;허환일;강건용;배충식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.74-82
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    • 2004
  • Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-off filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

A Study on the Machining Characteristics for Micro Endmilling by using Ultrahigh-Speed Air Turbine Spindle (초고속 스핀들에 의한 마이크로 엔드밀링의 가공특성에 관한 연구)

  • Kwon D.H.;Kang I.S.;Kim J.H.;Kang M.C.;Kim J.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.10a
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    • pp.598-603
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    • 2005
  • Recently, the advanced industries using micro parts are rapidly growing. The appearance of ultra-precision feed mechanism and the development of control system make it possible to process parts in sub millimeter scale by mechanical methods. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro parts to micro products. So, micro stairs have been trying to cut by using high revolution air turbine spindle and micro-endmill, and studying for magnitude of cutting force. This investigation deals removal characteristics of burr generated by micro endmilling process. Also, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. In micro endmilling, the material removal rate(MRR) and cutting forces are very small. This paper presents an investigation on the machining characteristics for micro stairs by using ultrahigh-speed air turbine spindle in machining.

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Fabrication of AlGaAs/InGaAs/GaAs Pseudomorphic HEMT's for mm waves. (mm파 AlGaAs/InGaAs/GaAs Power PM-HEMT 제작 연구)

  • 이성대;허종곤이일형이진구
    • Proceedings of the IEEK Conference
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    • 1998.10a
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    • pp.633-636
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    • 1998
  • In this study, power AlGaAs/InGaAs/GaAs PM-HEMT's for mm wave's were fabricated using Electron beam lithography and air-bridge techniques, and so on. DC and AC characteristics of the fabricated power PM-HEMTs were measured under the various bias conditions. For example, DC and RF characteristics such as S21 gain of 3.6 dB at 35 ㎓, current gain cut-off frequencies of 45 ㎓ and maximum oscillation frequencies of 100 ㎓ were carefully analyzed for design methodology of sub-mm wave power devices.

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A Stock Removal Cycle with Collision Detection Function for Turning Operation (충돌회피 기능을 가진 선삭용 황정삭 싸이클)

  • 임상묵;강성균;최종률
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1050-1053
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    • 1995
  • A stock removal cycle is developed as a programming tool of the CNC lathe. This cycle support the easiness and swifness of a part program generation in the shopfloor. The cycle contains the function of tool path generation of rough/finish cutting, of avoidance air-cut for non-cylindrical (die-casted, forged) workpiece, and of the tool collisopn detection/aviodance. Consequently the intelligent stock removal cycle results in improving the productivity and safety of CNC lathe.

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Study on Multi-Nozzle Virtual Impactor (멀티 노즐 가상 임팩터에 관한 연구)

  • 김대성;김민철;이규원
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2000.04a
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    • pp.227-228
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    • 2000
  • 가상 임팩터(virtual impactor)는 가속노즐(acceleration nozzle)아래에 충돌판(impaction plate) 대신 가상의 공간을 가진 수집관(receiving tube)이 설치되어 유선의 방향이 $90^{\circ}$로 바뀔 때, 큰 입자는 유선에서 벗어나 수집노즐에 포집된다(Hounam and Sherwood, 1965). 가상 임팩터에는 관성 임팩터(inertial impactor)와는 다르게, 절단입경(cut-size)보다 큰 입자를 분리할 수 있는 부 유동(minor flow)과 절단입경보다 작은 입자를 분리할 수 있는 주 유동(major flow)으로 나눈다. (중략)

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Using Continuous Flow Data to Predict the Course of Air Leaks After Lung Lobectomy

  • Jaeshin Yoon;Kwanyong Hyun;Sook Whan Sung
    • Journal of Chest Surgery
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    • v.56 no.3
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    • pp.179-185
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    • 2023
  • Background: Assessments of air leaks are usually performed subjectively, precluding the use of air leaks as an evaluation factor. We aimed to identify objective parameters as predictive factors for prolonged air leak (PAL) and air leak cessation (ALC) from air flow data produced by a digital drainage system. Methods: Flow data records of 352 patients who underwent lung lobectomy were reviewed, and flow data at designated intervals (1, 2, and 3 hours postoperatively [POH] and 3 times a day thereafter [06:00, 13:00, 19:00]) were extracted. ALC was defined by flow less than 20 mL/min over 12 hours, and PAL was defined as ALC after 5 days. Cumulative incidence curves were obtained using Kaplan-Meier estimates of time to ALC. Cox regression analysis was performed to determine the effects of variables on the rate of ALC. Results: The incidence of PAL was 18.2% (64/352). Receiver operating characteristic curve analysis showed cut-off values of 180 mL/min for the flow at 3 POH and 73.3 mL/min for the flow on postoperative day 1; the sensitivity and specificity of these values were 88.9% and 82.5%, respectively. The rates of ALC by Kaplan-Meier analysis were 56.8% at 48 POH and 65.6% at 72 POH. Multivariate Cox regression analysis revealed that the flow at 3 POH (≤80 mL/min), operation time (≤220 minutes), and right middle lobectomy independently predicted ALC. Conclusion: Air flow measured by a digital drainage system is a useful predictor of PAL and ALC and may help optimize the hospital course.

Mild Heat Treatments for Quality Improvement of Fresh-cut Potatoes (열처리가 신선편이 감자 가공품의 품질에 미치는 영향)

  • Lim Jeong-Ho;Choi Jeong-Hee;Hong Seok-In;Jeong Moon-Cheol;Kim Dongman
    • Food Science and Preservation
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    • v.12 no.6
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    • pp.552-557
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    • 2005
  • Effect of pre- and post-mild heat treatment on quality of fresh-cut potatoes was investigated with the focus on surface color, firmness, phenolics, vitamin C and sensory characteristics. As the pre-heat treatment before cutting of potatoes, dried hot air (DH) and hot water (WH) treatment were conducted at $45^{\circ}C$ for 60 min, respectively. As a post-heat (CH) treatments, potato cubes were dipped into water of $55^{\circ}C$ for 45 seconds after cutting. The potato cubes were packed in 15 cm x 20 cm LDPE pouches $30^{\mu}m$ thick and then stored at $5{\pm}1^{\circ}C$. The respiration rate of fresh-cut potatoes was decreased by mild heat treatment Especially, the rate of cubes treated with DH was decreased by $20\%$ compared to that of the non-heat treated. L value of cubes treated with DH showed higher value than that of others. Firmness and free phenolics had no significant difference between the treatments. The fresh-cut potatoes prepared with non-heat treatment showed higher vitamin C content than that of the heat treated. In sensory visual color, CH treated cubes marked the best quality. Conclusively, mild heat treatment, especially CH treatment, showed positive effect on browning inhibition and quality enhancement of fresh-cut potatoes.