• Title/Summary/Keyword: thermal pollution

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Changes in GC/PFPD Sensitivity in Relation with a Thermal Desorbing Technique for the Analysis of Sulfur Compounds: Comparison of Fixed Standard Concentration(FSC) vs Fixed Standard Volume(FSV) (열탈착 방식을 연계한 GC/PFPD 시스템으로의 주입방식 차에 따른 악취황 성분의 검량특성: 주입부피 대비 주입농도의 고정방식 간 비교연구)

  • Lee, Gi-Han;Kim, Gi-Hyeon
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2007.10a
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    • pp.106-108
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    • 2007

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Numerical Simulation Experiment on the Wind Ventilation Lane of the Local Circulation Winds in Daegu (대구지역의 국지적 대기순환풍의 환기경로에 관한 수치모의 실험)

  • Gu, Hyeon Suk;Kim, Hae Dong;Gang, Seong Dae
    • Journal of Environmental Science International
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    • v.13 no.4
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    • pp.367-376
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    • 2004

  • In urban area, thermal pollution associated with heat island phenomena is generally regarded to make urban life uncomfortable. To overcome this urban thermal pollution problem, urban planning with consideration of urban climate, represented by the concept of urban ventilation lane, is widely practiced in many countries. In this study, the prevailing wind ventilation lane of a local winds in Daegu during the warm climate season was investigated by using surface wind data and RAMS(Reasonal Atmospheric Model System) simulation. The domain of interest is the vicinity of Daegu metropolitan city(about 900 $km^{2})$ and its horizontal scale is about 30km. The simulations were conducted under the synoptic condition of late spring with the weak gradient wind and mostly clear sky. From the numerical simulations, the following two major conclusions were obtained: (1)The major wind passages of the local circulation wind generated by radiative cooling over the mountains(Mt. Palgong and Mt. Ap) are found. The winds blow down along the valley axis over the eastern part of the Daegu area as a gravity flow during nighttime. (2)After that time, the winds blow toward the western part of Daegu through the city center. As the result, the higher temperature region appears over the western part of Daegu metropolitan area.

  • https://doi.org/10.5322/JES.2004.13.4.367 인용 PDF KSCI

A Comparison of the Cooling Effects for the Compressed Cold Air and Coolant on the Cylindrical Grinding with WA Wheel (WA 숫돌을 이용한 원통 연삭 시 압축냉각공기와 연삭유의 냉각효과에 관한 연구)

  • Lee, Seok-Woo;Choi, Hon-Zong;Jeong, Hae-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.10
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    • pp.155-161
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    • 2000

  • Recently, environmental pollution has become a big problem in industry and many researches have been done in order to preserve the environment. In the grinding process, the coolant has great influence on environment. It contains several chemicals(sulfur, phosphorus and chlorine) to improve the grinding efficiency. If these additives go into the workplace atmosphere, it is harmful for workers. It can also cause the environment pollution. Because of these reasons many studies have been done to minimize the amount of coolant. However the small amount of coolant can cause the thermal defect on the ground surface layer. This study forced the effects of the compressed cold air when the spindle shaft materials(SCM4 & SCM21) were cylindrical ground with WA wheel. The compressed cold air was used as the coolant and grinding performance was compared with that of the conventional grinding fluids(emulsion). Many experiments were carried out with these two cooling materials. The surface roughness, residual stress, and roundness were measured for the cylindrical grinding. The test results showed that the compressed cold air was very useful as the cooling materials for grinding process. It was also efficient to minimize the thermal defects of workpiece and could also play a role in solving environmental pollution.

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