• Title/Summary/Keyword: Dry periods

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The Importance of Dry Deposition : Dry Deposition Fluxes of Heavy Metals In Seoul, Korea During Yellow-Sand Events

  • Yi, Seung-Muk
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2003.06a
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    • pp.76-85
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    • 2003
  • Mass and elemental dry deposition fluxes and ambient particle size distributions were measured using dry deposition plates and a cascade impactor, from March to November 1998 in Seoul, Korea. During the spring sampling period several yellow sand events characterized by long range transport from China and Mongolia impacted the area. During these events the mass fluxes were statistically the same as during springtime non-yellow-sand events. However, most elemental fluxes were higher. In general, the flux ratios of both crustal (Al, Ca, Mn) and anthropogenic elements (Ni, Pb) to total mass measured during the daytime yellow-sand events were substantially higher than those measured in spring daytime during non-yellow-sand time periods. During all seasons the average measured daytime fluxes were about two times higher than at nighttime. The flux of primarily anthropogenic metals (Cu, Ni, Pb, Zn) and Mn was on average one to two orders of magnitude lower than the flux of the crustal metals Al and Ca. As is typically found two modes, fine (0.1∼l.0 $\mu\textrm{m}$) and coarse (1.0∼10.0 $\mu\textrm{m}$) were present in the measured size distributions (<10 $\mu\textrm{m}$). The particles in the coarse mode constitute a major portion of the measured mass size distribution during the yellow-sand events possibly due to the long-range transport of those particles from China.

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The 17th Century Dry Period in the Time Series of the Monthly Rain and Snow Days of Seoul (서울의 강우와 강설 일수 자료에 나타난 17세기 말엽의 건조기)

  • Lim, Gyu-Ho;Choi, Eun-Ho;Koo, Kyosang;Won, Myoungsoo
    • Atmosphere
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    • v.22 no.3
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    • pp.381-386
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    • 2012
  • The monthly number of days with rain or snow in Seoul extends backward to 1626 from the present. The number of rain and snow days are from the ancient records and combined with the modern precipitation records from 1907 to the present. There are two distinct and abrupt changes in the time series, which allow us to divide the entire period into three sub-periods of CR-I, CR-II, and MR. For each sub-period, we calculated the basic statistics and the associated distributions. The analysis proves Seoul, which may comprise East Asia when considering the lengthy period of dry condition, had dry climate for the Maunder Minimum when Europe experienced cold climate. We also note relationships between the rain days and sunspot numbers in various frequency bands.

Effects of MH, FA, Flumetralin and Butralin Applications on Sucker Control of Flue-cured Tobacco (황색종 담배에서 MH, FA, Flumetralin 및 Butralin의 처리방법이 곁순억제에 미치는 영향)

  • 류명현;김용암
    • Journal of the Korean Society of Tobacco Science
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    • v.23 no.1
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    • pp.5-11
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    • 2001
  • Experiments were conducted to evaluated the sucker control efficiency of several suckercides and their combinations for flue-cured tobacco in Korea. In 1999, Flumetralin(Prime+, P+), Butralin(B), Fatty alcohol(FA, n-decanol 85%), pottasium salt of maleic hydrazide(MH), tank mix of MH with P+ (MH·P+), and another tank mix of MH with FA(MH·FA) were applied after topping, respectively, then sucker number and sucker dry weight were investigated on the 30th and 50th day from treatment. Sucker number and dry weight were significantly lowered by P+, B, FA and MH·P+ applications compared with those of MH and MH·FA for both investigated periods. A significant reduction in sucker number and dry weight was observed in P+, B, and MH·P+ applications. FA treatment was not so much effective in sucker control as P+. In 1999 and 2000, several suckercides and tank mixes of their combinations were applied first at button stage and second after topping, respectively, to compare the effects of sucker control on yield, price index and chemical components of cured leaves. Compared to the standard method of FA 30x at button stage followed by MH40x application after topping(FA 30x + MH 40x), sucker number and dry weight decreased by [FA 30x (or P+ 1%] or [FA 30x(or B 1.5%) + MH 60x·B 1.5%] treatments, even at reduced MH levels. But yield, price index and chemical components of cured leaves were not differed among treatments.

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Deposition Characteristics of Atmospheric PCBs Depending on Exposure Periods Using Pine Needles (소나무 잎을 이용한 대기 중 PCBs의 노출기간별 침착특성)

  • Yeo, Hyun-Gu;Cho, Ki-Chul;Choi, Min-Kyu;Kim, Tae-Wook;Chun, Man-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.8
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    • pp.836-842
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    • 2006
  • Pine needle samples(1 year, 2 year, 3 year old) were collected in Seoul and Ansung to investigate the deposition characteristics of atmospheric PCBs depending on exposure periods. Total PCBs concentration of pine needle samples in Seoul and Ansung showed 2,429, 1,198 pg/g DW(dry weight), respectively. PCB homologs concentration of pine needle samples decreased with increasing chlorine-substituted compounds. It showed that higher chlorine- substituted compounds in existing particle phase compared to lower chlorine-substituted compounds existing in gaseous phase were difficult to accumulate lipids of the pine needles samples. The results of regression analysis between exposure periods in the atmosphere and concentration of total PCBs measured in pine needles at two sites showed significant levels($R^2>0.94$, p<0.01), which implies that atmospheric PCBs accumulated on pine needles with positive linearity depending on exposure periods in this study. Therefore pine needle samples can be used as passive air sampler(PAS) for monitoring air contamination for a long time in different sites.

Washoff Characteristics and Correlation of Nonpoint pollutants in a Bridge Storm Runoff (교량 강우유출수내 비점오염물질의 유출특성 및 상관성)

  • Wee, Seung-Kyung;Kim, Lee-Hyung;Jung, Yong-Jun;Gil, Kyung-Ikt
    • Journal of Korean Society on Water Environment
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    • v.24 no.3
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    • pp.378-382
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    • 2008
  • During the dry periods, many types of pollutants are being accumulated on the paved surface by vehicle activities and the accumulated various pollutants are inflowing into the near watershed areas for the rainfall periods. Particularly, bridges are the centralized region to be the surface runoff of the stromwater due to the high ratio of the impermeable area. Also, the metals, toxic chemicals and sediments originated from bridges could be strongly influenced to the watershed areas during the runoff. Therefore, the present study is achieved to provide washoff characteristics and correlation from the bridge during rainfall periods. The result shows that the EMC ranges for 95% confidence intervals in a bridge land use are 10.12~128.09 mg/L for TSS, 6.07~21.15 mg/L for BOD, 2.10~6.70 mg/L for TN and 0.06~0.85 mg/L for TP.

Development of Bin Weather Data for Simplified Energy Calculations (간역열부하계산용(簡易熱負荷計算用) Bin기상(氣象)데이터)

  • Kim, Doo Chun;Choi, Jin Hee
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.17 no.1
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    • pp.28-43
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    • 1988
  • The purpose of this research is to produce bin weather data for Seoul from Standard Weather Data. The intended use of these data is for input to recently developed models for simplified energy calculations and for generating variable-base degree-day information. The data produced under this study include $3^{\circ}C$ bin data covering the full range of dry-bulb temperatures with mean coincident wet-bulb and daytime coincident solar radiation, wet-bulb bins down to freezing temperature, wind speed bins with prevailing directions, and heating and cooling degree hours to nine different temperature bases. All of these data are tabulated in six separate time periods and total daily categories for monthly and annual periods.

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Washoff Characteristics of Nonpoint pollutants in Paved Areas (포장지역내 비점오염물질의 유출특성)

  • Gil, Kyung-Ik;Wee, Seung-Kyung;Lee, Sang-Soo;Park, Moo-Jong
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.779-782
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    • 2008
  • During the dry periods, many types of pollutant are accumulating on the paved surface by vehicle activities and accumulated various pollutants are inflowing to the near watershed areas for the rainfall periods. Also, the metals, toxic chemicals and sediments originated from bridges could be strongly influenced to the watershed areas during the runoff. The result shows that the EMC ranges for 95% confidence intervals in a bridge land use are $10.12\sim128.09mg/L$ for TSS, $6.07\sim21.15mg/L$ for BOD, $2.10\sim6.70mg/L$ for TN and $0.06\sim0.85mg/L$ for TP.

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Development of a Modified Standardized Precipitation Index by Considering Effects of the Dry Period and Rainfall (무강수일수와 강우효과를 고려한 개선된 표준강수지수 개발)

  • Lee, Jun-Won;Kim, Gwang-Seob
    • Journal of Korea Water Resources Association
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    • v.45 no.4
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    • pp.409-418
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    • 2012
  • A modified standardized precipitation index was developed by considering the length of dry period and surface run-off effect. The official reports and newspapers on drought from 1973 to 2009 were quantified to evaluate drought indices. The developed index was evaluated using the receiver operating characteristic analysis. In order to suggest improved drought index, we cut the precipitation amount that may do not contribute the mitigation of drought and weight dry period by considering cumulative distribution, decile distribution of dry periods. Drought detection capability of the suggested index has improved by weighting of dry period effects and considering precipitation amounts contributing drought mitigation.

Changes in Characteristic Proteins during Chilling of Dressed broilers (Dressed broilers의 냉장중(冷藏中) 특수단백질(特殊蛋白質) 변화(變化))

  • Lee, Young-Choon
    • Applied Biological Chemistry
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    • v.14 no.2
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    • pp.165-169
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    • 1971
  • From both breast and leg muscle of 12 week-old broiler chicken held for aging in slushed ice and dry chilling at $33-35^{\circ}F$., myosin, actomyosin and other nitrogenous fractions were extracted with KCl-phosphate buffer for various periods from 1 hr. to 25 hr. post-mortem. The changes in extractable nitrogen occurred mainly as a result of decrease in extractability of myosin and to some extent, increase in extractability of actomyosin. Changes in stroma, sarcoplasmic and NPN fractions were small. Myosin extractability decreased rapidly during the first 3 hr. post-mortem and then reduced Continuously in both leg muscle and breast muscle during wet chilling. The decrease of myosin extractability in leg muscle was much more than that in breast muscle, and then the extractability increased after 17 hr. post-mortem in dry chilling. Actomyosin was extracted at low consistent level in wet chilling, while it increased considerably after 17 hr. post-mortem in dry chilling. The tendency was similar in both breast and leg muscle.

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The Effects of Salting Levels and Drying Periods on Weight Loss and Nutritional Compositions of Dry-cured Ham under Controlled Ripening Condition (건염햄 제조시 소금수준과 건조기간이 제품 중량감소 및 영양적 특성에 미치는 영향)

  • Seong, Pil-Nam;Cho, Soo-Hyun;Kang, Geun-Ho;Kim, Jin-Hyoung;Park, Beom-Young;Jeong, Da-Woon;Jung, Jae-Hong;Jeong, Seok-Geun;Kim, Dong-Hoon
    • Journal of Animal Science and Technology
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    • v.54 no.1
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    • pp.35-41
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    • 2012
  • The aim of this study was to offer information about appropriate processing method for dry cured-ham with controlled ripening condition. In this study, three different treatments were performed: High salt group (HS), 18 hams were salted with 70 g $kg^{-1}$ salt (w/w) Middle salt group (MS), 18 hams were salted with 50 g $kg^{-1}$ salt Low salt group (LS), 18 hams were salted with 30 g $kg^{-1}$ salt. Also three drying periods were applied (180 days, 270 days and 360 days). The weight loss in HS was higher (5.62%) on curing step and in LS was higher (12.35%) on post-salting step compared to other groups. On fermentation stage, weight loss of HS was higher than that of LS (p<0.05). Weight loss on drying was increased as the drying period passes (p<0.05). Moisture contents were significantly (p<0.05) decreased and fat contents were significantly (p<0.05) increased in all treatment groups as drying period increased. The different drying periods affected fatty acid compositions on all salting levels; saturated fatty acid contents were increased (p<0.05) with more drying, whereas unsaturated fatty acid contents were decreased (p<0.05) as drying period increased.