간행물
한국환경과학회지 KCI 등재 Journal of Environmental Science International
- 발행기관 한국환경과학회
- 자료유형 학술지
- 간기 월간
- ISSN 1225-4517 (Print)2287-3503 (Online)
- 수록기간 1992 ~ 2023
- 주제분류 자연과학 > 자연과학일반 자연과학 분류의 다른 간행물
- 십진분류KDC 539DDC 628
권호리스트/논문검색
제4권 제1호 (1995년 3월) 10건
1.
1995.03
서비스 종료(열람 제한)
The assessment for a degree of drought has been carried out based on the soil moisture index in Korea. The soil moisture index(Im) was calculated assuming of constant evapotranspiration until wilting point as Im = w_2/w_f·100. The soil moisture content(W2) at the final of a period is obtained from W2 = Pe + W1 - E, here the effective precipitation amount is Pe, evapotranspiration E, and the soil moisture content at the beginning of a period is W1. The filed capacity(Wf), as a mean value of fine sandy loams, was reduced to 92 ㎜/ft when we accept the wilting point and the available soil moisture content of 42 ㎜/ft, respectively. The drought begins in Korea when the soil moisture index drops to less than 50%. The value coincides the isoline of 11 or more consecutive days without measureable precipitation. The soil moisture index frequently drops in the northern part of Youngnam area and Honam area so that both areas are well known as the areas of drought.
2.
1995.03
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In order to examine the effect on the insolation of cloud cover, we analyzed the data of the insolation, cloud (over and surface air pressure in Pusan during the period of 1991. 10 - 1993.1. At first, we investigate the atmospheric transmissivity A(t) using the Beer`s law at clear skies. The atmospheric transmissivity is characterized by cold season high and warm season low. From this atmospheric transmissivity, the empirical formula that shows the variation of the insolation due to the cloud cover is obtained. The result formula is I = I_0 A(t^n)(0.7 - 0.05 × m ). I is the insolation that reaches the surface when cloud cover is m and I_0 is solar constant. Although the result is some rough it seems meaningful that the estimation of insolation can be made only from the routine data.
3.
1995.03
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A rainfall runoff model described in this paper which is based on Basin- wide Ecological Model(BAWEM) calculates the fate of agro-chemicals in a watershed located of golf links. The rainfall runoff coefficients of agro-chemicals,which are the dominant parameters to predict the movement of agro-chemicals from soil and turfgrass to downstream water, are estimated. Also, the model is used to estimate the level of health risks the residents around golf links are exposed to. The fidelity of rainfall runoff model of agro-chemicals was validated by the observed data obtained during rainy period. The calculated results from this model were found to be in the same order of that of the observed. The rainfall runoff coefficients of four agro-chemicals used in golf links were 5.4×10 exp (-3), 1.9×10 exp (-3), 3.0×10 exp (-4) and 4.4×10 exp (-3) for flutolanil, isoprothiolane, chlorpyrifos and simazine, respectively. The health risk level to the residents around golf links is evaluated to be rather low: the ratio of estimated dose through drinking water to the 10% of ADI(Acceptable Daily Intake) value or VSD for 10^-6 life time risk varied in the range of 0.005∼0.04 and 0.003∼0.11, respectively, for both the annual mean and maximum monthly mean cases.
4.
1995.03
서비스 종료(열람 제한)
Transport rate of windblown dusts such as soil, sand, snow is proportionate to U_*^3 and U_*, friction velocity, approximately to flow velocity of wind. Therefore, through measurement and the flow velocity of wind, it turned out that,considering different velocity distributions caused by downstream distance and porosity percent,windbreaks with appropriate porosity rate to the protection area should be chosen for the optimal fence effect. In the economic respect, better are fences with gap of 20%∼30%. Among the windbreaks to have the optimal fence effect.
5.
1995.03
서비스 종료(열람 제한)
The effects of reaction temperature, SO_2 and CO_2 concentration in an air gas stream, particle sizes of limestone on the reactivity and capacity of SO_2 removal have been determined in a thermogravimetric analyser(TGA). The apparent reaction order of sulfation reaction of pre-calcined lime(CaO) with respect to SO_2 is found to be close to unity. The apparent activation energies are found to be 17,000 ㎉/kmol for sulfation of pre-calcined lime and 19,500 ㎉/kmol for direct sulfation of limestone(CaCO_3). The initial sulfation reaction rate of pre-calcined lime increases with increasing temperature, whereas the sulfur capture capacity exhibits a maximum value at 900℃. In direct sulfation of limestone, sulfation reactivity and sulfur capature capacity of sorbent increase with increasing temperature and decreasing CO_2 concentration in a gas bulk stream. The main pore of pre-calcined lime is shifted to the larger pore sizes and pore volume decreases with increasing sulfation time and temperature. The surface area of lime decreases with increasing calcination temperature under an air atmosphere, whereas is rearly constant under a CO_2(5, 10%) atmosphere in a gas stream.
6.
1995.03
서비스 종료(열람 제한)
To collect and evaluate an aerosol acidity (H^+) in ambient air, the cyclone/annular denuder/filter pack sampling system (ADS) was used. Aerosol acidity was collected in Chicago using the ADS for 81 12-hr samples divided in spring/summer/fall 1990 and winter 1991. This study illustrated that the ADS was suitable for measuring aerosol acidity. The 10^-5N HClO_4 extraction solution for pH determination provided more reliable scale than 10^-4N HClO_4. NH_3 should be removed prior to particle collection to accurately measure H^+ concentration on the filter. There was seasonal variation in aerosol acidity concentrations. Aerosols were more acidic in the summer. High correlations between SO_4^2- and NH_4^+, and between SO_4^2+ and H^+ were observed during the entire sampling period.
7.
1995.03
서비스 종료(열람 제한)
Continuous measurements of ground-level ozone (O_3) were made in five minutes intervals in the rural area of Korea from July 1993 to June 1994. This site is located in Chongwon, near latitude 36.4˚ N, longitude 127.6˚ E. The results show that the one-year mean value was 17 ppb, and monthly mean ranged from 6 to 47 ppb. A pronounced maximum in summer and a minimum in winter were found, and these were related to anthropogenic emission and photochemical reaction. Diurnal variations of ozone concentration showed a normal distribution with a maximum at 15:00 - 16:00 and a minimum at 07:00 - 08:00. During the period when ozone concentration was very high (> 80 ppb), the stable winds were from N and NW; on the other hand, when ozone concentration was very low, air movement in the large scale was from the North Pacific Ocean. This suggests that in the rural area the long range transport of anthropogenic pollutants from distant sources can contribute to the larger contribution than the generation of ozone from local sources in the rural area.
8.
1995.03
서비스 종료(열람 제한)
A discrete state space model for a multiple-reach river system is formulated using the dynamics of biochemical oxygen demand(BOD) and dissolved oxygen(DO). A hierarchical optimization technique, which is applicable to large-scale systems with time-delays in states, is also described to control stream quality in a river as an optimal manner based on the interaction prediction method. The steady state tracking error of the proposed method is determined analytically and a necessary and sufficient condition on which a constant target tracking problem has zero steady-state error is derived. Computer simulations for the river pollution model illustrate the algorithm.
9.
1995.03
서비스 종료(열람 제한)
In order to provide the basic information for the water quality modeling, the water pollution indicators of Sin stream and Keumho river flowing through Taegu city were measured, and the periodical variations of these indicators were studied under the condition of stagnating for 19 days. For this experiment, three sampling sites(Sungpook bridge, Mutae bridge and Gangchang bridge) were selected. Sungpook bridge is located most down the Sin stream, Mutae bridge and Gangchang bridge are located on the lower Keumho river. The results were as follows. 1. The values of water pollution indicators measured at Mutae bridge were pH 8.7, TSS 51㎎/ℓ, TS 383㎎/ℓ, Cl^- 60.68㎎/ℓ, turbidity 32FTU, DO 8.58㎎/ℓ, oxygen deficit 2.02㎎/ℓ, COD 16.32㎎/ℓ, organic carbon 13.60㎎/ℓ. 2. At Gangchang bridge located down more than Mutae bridge, the values of these indicators were pH 8.0, TSS 26㎎/ℓ, TS 737㎎/ℓ, Cl^- 90.59㎎/ℓ, turbidity 37FTU,DO 3.49㎎/ℓ, oxygen deficit 7.11㎎/ℓ, COD 28.02㎎/ℓ, organic carbon 14.28㎎/ℓ. 3. At Sungpook bridge, the values of these indicators were pH 8.3, TSS 145㎎/ℓ, TS 344㎎/ℓ, Cl^- 32.51㎎/ℓ, turbidity 60FTU, DO 6.53㎎/ℓ, oxygen deficit 4.07㎎/ℓ, COD 43.79㎎/ℓ, organic carbon 11.03㎎/ℓ. 4. At Mutae bridge and Sungpook bridge of which initial DOs were high, DOs have decreased under the condition of stagnating for 7 days and increased after that time. On the contrary, at Gangchang bridge of which oxygen deficit was very high(7.11mg/l), DO have increased under the condition of stagnating for 13 days and decreased after that time. 5. All the samples showed the quick decrease of CODs and organic carbons under the condition of stagnating for 19 days. Nevertheless, at Sungpook bridge of which initial COD was very high (43.79㎎/ℓ), the value of COD measured at the last day of experiment was still high(21.35㎎/ℓ), because of a large quantity of reducing inorganic matters. 6. All the samples didn`t show the distinct decrease of turbidities because of a large quantity of nonbiodegradable inorganic solids.
10.
1995.03
서비스 종료(열람 제한)
The reaction rate, equilibrium, and flow injection analysis methods were fundamentally evaluated for the determination of aqueous ammonia. The selected indophenol blue method was based on the formation of indophenol blue in which ammonium ion reacted with hypochlorite and phenol in alkaline solution. In the optimized reaction condition, the reaction followed 1st order reaction kinetics and the final product was stable. The absorbance measurements before and after the equilibrium were utilized for the reaction rate and equilibrium methods. The reaction rate methods, based on the relative analytical signals for the possibility of eliminating interferents, were shown to have good linear calibration curves but the detection limit and the calibration sensitivity were poorer than those in the equilibrium method. The detection limits were 32-49 ppb and 24 ppb for the reaction rate and equilibrium methods, respectively. In the flow injection analysis, the absorbance was measured before the equilibrium reached and thus resulted in 30% reduction of calibration sensitivity. However, the detection limit was 11 ppb, indicating that the peak-to-peak noise for the blank was remarkably improved. Compared to the manual methods, the optimized experimental condition in a closed reaction system reduced the blank absorbance and the inclusion of ammonia from the atmosphere was prevented. In addition, highly reproducible mixing of sample and reagents and analytical data extracted from continuous recording showed excellent reproducibility.
