• Title/Summary/Keyword: Climate Control

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Comparison of the Real-time Measurements for PM2.5 and Quality Control Method (PM2.5 자동측정장비 비교 및 정도관리 방안)

  • Park, Mikyung;Park, Jin Su;Jo, Mira;Lee, Yong Hwan;Kim, Hyun Jae;Oh, Jun;Choi, Jin Soo;Ahn, Joon Young;Hong, You Deog
    • Journal of Korean Society for Atmospheric Environment
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    • v.33 no.6
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    • pp.616-625
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    • 2017
  • Measurements using five real-time particle samplers were compared to measurements using three NRM (National Reference Method system) filter-based samplers(Gravimetric method) at Incheon, Korea, between May and August, 2014. The purpose of this study was to suggest the quality assurance/quality control (QA/QC) method of each instrument for use in a real-time continuous particle sampler to measure the mass of airborne particles with an aerodynamic diameter less than $2.5{\mu}m$ ($PM_{2.5}$). Five real-time particle samplers of BAM1020, FH62C_14, TEOM, PM-711 and SPM-613 were evaluated by comparing its measured 23 hr average $PM_{2.5}$ concentrations with those measured with NRM filter-based samplers simultaneously. The parameters(e.g. Inlet heating condition, Slope factor, Film response, Intercept, Background, Span value) of the real-time samplers were optimized respectively by conducting test performance evaluation during 7 days in field sampling. For example, inlet heating temperature of TEOM sampler controls $35{\sim}40^{\circ}C$ to minimize the fluctuation of the real-time measurement data and background value of BAM1020 is the key factor affecting the accuracy of $PM_{2.5}$ mass concentration. We classified the $PM_{2.5}$ concentration according to relative humidity (80%) to identify water absorbed in aerosols by measuring the ${\beta}$-ray samplers(BAM1020, FH62C_14) and TEOM. ${\beta}$-ray samplers were not strongly affected by relative humidity that the difference of the average $PM_{2.5}$ concentration was about 5%. On the other hand, The TEOM sampler overestimated $PM_{2.5}$ mass concentration about 15% at low relative humidity (<80%).

Impact of Climate Change on Water Cycle and Soil Loss in Daecheong Reservoir Watershed (기후변화에 따른 대청호 유역의 물 순환 및 토양 유실량 영향)

  • Ye, Lyeong;Chung, Se Woong;Oh, Dong Geun;Yoon, Sung Wan
    • Journal of Korean Society on Water Environment
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    • v.25 no.6
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    • pp.821-831
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    • 2009
  • The study was aimed to assess the expected impact of climate change on the water cycle and soil losses in Daecheong Reservoir watershed, Korea using the Soil and Water Assessment Tool (SWAT) that was validated for the watershed in a previous study. Future climate data including precipitation, temperature and humidity generated by introducing a regional climate model (Mesoscale Model Version 5, MM5) to dynamically downscale global circulation model (European Centre Hamburg Model Version 4, ECHAM4) were used to simulate the hydrological responses and soil erosion processes in the future 100 years (2001~2100) under the Special Report on Emissions Scenario (SRES) A1B. The results indicated that the climate change may increase in the amount of surface runoff and thereby sediment load to the reservoir. Spatially, the impact was relatively more significant in the subbasin Bocheongcheon because of its lower occupation rate of forest land compared to other subbasins. Seasonally, the increase of surface runoff and soil losses was more significant during late summer and fall season when both flood control and turbidity flow control are necessary for the reservoir and downstream. The occurrence of extreme turbidity flow events during these period is more vulnerable to reservoir operation because the suspended solids that remained water column can be resuspended by vertical mixing during winter turnover period. The study results provide useful information for the development of adaptive management strategy for the reservoir to cope with the expected impact of future climate change.

Comparison of CH4 Emission between Auto Chamber and Manual Chamber in the Rice Paddy (벼논에서 자동 챔버와 수동 챔버를 이용한 CH4 배출량 비교)

  • Jeong, Hyun Cheol;Choi, Eun Jung;Lee, Jong Sik;Kim, Gun Yeob;Lee, Sun Il
    • Journal of Climate Change Research
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    • v.9 no.4
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    • pp.377-384
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    • 2018
  • The chamber method is widely used for measuring methane emission from paddy rice fields. The closed static chamber has advantages of easy installation and removal in the field and low manufacturing cost. However, the manual chamber method requires a lot of labor and has a limited sampling time and frequency. To overcome the disadvantages of the manual chamber, the auto-chamber system is used for measuring methane emission. We compared the differences in methane flux between the auto-chamber and manual chamber. To investigate methane emissions by the two methods, a chamber was installed for each of the following treatments : control without rice straw (NA), spring plowing after autumn rice straw application (SPRA) and autumn plowing after autumn rice straw application (APRA). The total methane emission was lowest in the control and highest in APRA with both methods. There was no significant difference in total methane emission between the methods, but dynamic fluctuation in methane with temperature change was accurately measured in the auto-chamber. Measuring methane emission with an auto-chamber system is expected to reduce uncertainty and increase accuracy, accompanied by labor reduction.

Determination of Economic Control Thresholds for Bacterial Spot on Red Pepper Caused by Xanthomonas campestris pv. vesicatoria (고추 세균점무늬병 발생에 따른 수량 변화와 경제적 방제수준 설정)

  • Kim, Ju-Hee;Cheong, Seong-Soo;Lee, Ki-Kwon;Yim, Ju-Rak;Lee, Wang-Hyu
    • Research in Plant Disease
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    • v.21 no.2
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    • pp.89-93
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    • 2015
  • This study was carried out to develop the economic thresholds for the control of bacterial spot of red pepper. The correlation between diseased leaf rate and yield in field was Y=-0.724X+281.58, $R^2=0.78$, $r=-0.88^{**}$. The correlation between diseased leaf rate and yield loss in field was Y=0.813X+15.95, $R^2=0.78$, $r=0.88^*$.We found that control thresholds was below 30.3% diseased leaves rate per plant in field. The economic control thresholds for bacterial spot of red pepper was below 16.3%.

Furrow Cover Effects of Black Non-woven Fabric on Reduction of Nitrogen and Phosphorus Discharge from Upland Soil Used for Red Pepper Cultivation

  • Hong, Seung Chang;Kim, Min Kyeong;Jung, Goo Buk;So, Kyu Ho
    • Korean Journal of Soil Science and Fertilizer
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    • v.48 no.6
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    • pp.671-676
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    • 2015
  • Control of surface runoff from upland soil is essential to reduce nonpoint source pollution. The use of non-woven fabric as a soil cover can be helpful to control surface runoff. The field experiment was conducted to evaluate the furrow cover effects of black non-woven fabric on the nutrient discharge from upland soil used for red pepper cultivation. The experimental plots consisted of chemical fertilizer (CF), cow manure compost (CMC), and pig manure compost (PMC) treatment. Each nutrient material treatment plot has control (no furrow cover (NFC)) and black non-woven fabric cover treatment, respectively. The amount of nutrient application was chemical fertilizer of $190-112-149(N-P_2O_5-K_2O)kgha^{-1}$, cow manure compost of $29.5tonha^{-1}$, and pig manure compost of $7.9tonha^{-1}$ as recommended amount after soil test for red pepper cultivation. Compared to control (NFC), furrow cover treatment with black non-woven fabric reduced the amount of T-N discharge by 50% at CF treatment, 36.9% at CMC treatment, and 44.8% at PMC treatment. Furrow cover treatment with black non-woven fabric reduced the amount of T-P discharge by 37.1% at CF treatment, 49.9% at CMC treatment, and 63.4% at PMC treatment compared to control (NFC). The production of red pepper did not show significant difference. There was no weed occurring in furrow cover treatment plots with black non-woven fabric. Results from this study showed that the furrow cover with black non-woven fabric could play a significant role in reduce nutrient discharge from upland soil used for red pepper cultivation.

Performance Improvement of Sensorless Control of IPMSM using Active Flux Concept by Improved Current Estimators (유효 자속 개념을 이용한 IPMSM 센서리스 제어의 전류 추정기에 의한 성능개선)

  • Lee, Sung-Joon;Kim, Tae-Wan;Kim, Won-Seok;Kim, Marn-Go;Jung, Young-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.18 no.6
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    • pp.587-592
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    • 2013
  • In this paper, the performance improvement of the sensorless control of IPMSM employing the active flux concept by the improved current estimator is presented. The accuracy of the current estimator used in a previous report is degraded when the motor parameters are not known exactly. A simple current estimator derived from estimated flux is proposed to improve the position estimation performance. In order to show the usefulness of the proposed estimation method, the simulation results using Matlab/Simulink and the experiment results are presented.

Evaluation of carbonation service life of slag blended concrete considering climate changes

  • Wang, Xiao-Yong;Luan, Yao
    • Computers and Concrete
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    • v.21 no.4
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    • pp.419-429
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    • 2018
  • Climate changes, such as increasing of $CO_2$ concentration and global warming, will impact on the carbonation service life of concrete structures. Moreover, slag blended concrete has a lower carbonation resistance than control concrete. This study presents a probabilistic numerical procedure for evaluating the impact of climate change on carbonation service life of slag blended concrete. This numerical procedure considers both corrosion initiation period and corrosion propagation period. First, in corrosion initiation period, by using an integrated hydration-carbonation model, the amount of carbonatable substances, porosity, and carbonation depth are calculated. The probability of corrosion initiation is determined through Monte Carlo method. Second, in corrosion propagation period, a probabilistic model is proposed to calculate the critical corrosion degree at surface cracking, the probability of surface cracking, and service life. Third, based on the service life in corrosion initiation period and corrosion propagation period, the whole service life is calculated. The analysis shows that for concrete structures with 50 years service life, after considering climate changes, the service life reduces about 7%.

Prediction of reservoir sedimentation: A case study of Pleikrong Reservoir

  • Thu Hien Nguyen;XuanKhanh Do
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.36-36
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    • 2023
  • Sedimentation is a natural process that occurs in all reservoirs. Sedimentation problem reduces the storage capacity of the reservoir and limits its ability to provide water for various uses, such as irrigation, hydropower generation, and flood control. Therefore, predicting reservoir sedimentation is important for ensuring the efficient operation and sedimentation management of a reservoir and . In this study, the HECRAS model was applied to predict longitudinal distribution of deposited sediment in the Pleikrong reservoir to 2050. Different scenarios was considered: (i) no climate change, (ii) climate change (under two emissions scenarios, RCP4.5 and RCP8.5), and (iii) climate change and land use change (followed land use planning of the watershed). The computation results with different scenarios were analyses and compared. The results show that the reservoir reduced storage volume's rate and sedimentation proceed toward to the dam in the case of climate change is faster than in the case of no climate change. Analyses also indicates that following the land used planning could also improve the long-term problem of the reservoir sedimentation. The outcomes of this study will be helpful for a sustainable plan of sediment management for the Pleikrong reservoir.

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An Experimental Study on the Temperature and Humidity Evaluation in the Summer and Winter Season of the Korean Traditional Houses in Chonnam Province (전남지방 전통주택 하절기와 동절기의 온습도 평가에 관한 실험적 연구)

  • Lee, Tai-Kang;Choi, Eun-Seok;Kim, Hang;Kim, Hyung-Ryul;Gi, No-Gab;Kim, Sun-Woo
    • KIEAE Journal
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    • v.6 no.1
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    • pp.57-62
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    • 2006
  • Korean Traditional houses has been evolved and developed in many years, adopting the natural environment to control exterior conditions. These control method are various passive system of using natural materials, considering micro climate, building lay out, and these system are more natural and ecological to make the comfortable indoor climate than active systems of the present houses. This study aims to analyzed control performance of outdoor environment of five Korean traditional houses during the summer and winter. These houses are varied with lay out and floor plan to reflect the way of control for environmental condition, surveyed the reverberation time and sound level difference between rooms of the main living room and other main floored room, master room and kitchen. Especially air temperature and humidity have been measured simultaneously in each rooms to compare with outdoor condition. As a result, the variation of air temperature and humidity of most rooms are considerably static while condition of outdoors are much varied, it is showed that indoor climate has been controled with traditional soiled walls.