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
제18권 제7호 (2009년 7월) 12건
1.
2009.07
서비스 종료(열람 제한)
Bench-scale Experiment on Catalytic Decomposition of 1,2 Dichlorobenzene by Vanadia-Titania Catalyst
Catalytic activities of V2O5/TiO2 catalyst were investigated under reaction conditions such as reaction temperature, catalyst size, inlet concentration and space velocity. A 1,2-dichlorobenzene(1,2-DCB) concentrations were measured in front and after of the heated V2O5/TiO2 catalyst bed, and conversion efficiency of 1,2-DCB was determined from it's concentration difference. The conversion of 1,2-DCB using a pellet type catalyst in the bench-scale reactor was lower than that with the powder type used in the micro flow-scale reactor. However, when the pellet size was halved, the conversion was similar to that with the powder type catalyst. The highest conversion was shown with an inlet concentration of 100 ppmv, but when the concentration was higher or lower than 100 ppmv, the conversion was found to decrease. Complete conversion was obtained when the GHSV was maintained at below 10,000 h-1, even at the relatively low temperature of 250°C. Water vapor inhibited the conversion of 1,2-DCB, which was suspected to be due to the competitive adsorption between the reactant and water for active sites.
2.
2009.07
서비스 종료(열람 제한)
This research focuses on analyzing the problems of guideline signs, facilities and length of nature trails of Odaesan and Seoraksan national park, and aims to help the preservation of nature by increasing the efficiency of children's learning of nature by observing the usage of nature trails in the children's point of view. On-site research and questionnaire research took place in November 2008 and february 2008. Considering the contemporary problems, we have proposed the location change of guideline signs to be suitable for children and also the change of its design for children's increased attention.
3.
2009.07
서비스 종료(열람 제한)
To examine the fluctuations of aerosol number concentration with different size in the boundary layer of marine area during summer season, aerosol particles were assayed in the Ieodo Ocean Research Station, which is located 419 km southwest of Marado, the southernmost island of Korea, from 24 June to 4 July, 2008. The Laser Particle Counter (LPC) was used to measure the size of aerosol particles and NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 3 μm in diameter to smaller particles more than 1 μm in diameter with wind direction during precipitation. The aerosol number concentration decreased with increasing temperature. An increase (decrease) of small size of aerosol (0.3∼0.5 μm in diameter) number concentration was induced by convergence (divergence) of the wind fields. The aerosol number concentration of bigger size more than 3 μm in diameter after precipitation was removed as much as 89∼94% compared with aerosol number concentration before precipitation. It is considered that the larger aerosol particles would be more efficient for scavenging at marine boundary layer. In addition, the aerosol number concentration with divergence and convergence could be related with the occurrence and mechanism of aerosol in marine boundary layer.
4.
2009.07
서비스 종료(열람 제한)
Hydrochloric acid salt of a new N2O3 pentadentate ligand, N,N'-Bis(2-Hydroxybenzyl)-1,3-diamino-2-propanol(H-BHDP․2HCl) was synthesized. Br-BHDP․2HCl, Cl-BHDP․2HCl, CH3-BHDP․2HCl and CH3O- BHDP․2HCl having Br, Cl, CH3 and CH3O substituents at 5-position of the phenol group of H-BHDP․2HCl were also synthesized. The potentiometry study in aqueous solution revealed that the proton dissociations of the synthesized ligands occurred in four steps and their order of the calculated overall proton dissociation constants(logβp) was Br-BHDP〈 Cl-BHDP〈 H-BHDP〈 CH3O-BHDP〈 CH3-BHDP. The order showed a similar trend to that of Hammett substituent constants(δp). The order of the stability constants(logKML) was Co(Ⅱ)〈 Ni(Ⅱ)〈 Cu(Ⅱ)〈 Zn(Ⅱ)〈 Cd(Ⅱ)〈 Pb(Ⅱ). The order in their stability constants (logKML) of each transition metal complex agreed with that of the overall proton dissociation constants (logβp).
5.
2009.07
서비스 종료(열람 제한)
In this study, which aims to estimate the volume of greenhouse gas emitted by road transportation vehicles in Changwon City, the emission rate was calculated on the basis of the actual traffic volume measured at major crossroads and compared with the results obtained from the methodology used to estimate the greenhouse gas emissions of road transportation provided in the IPCC 2006 GL guidelines (Tier 1, Tier 3). Analysis of the results of the comparison showed that the Tier 1 methodology, which was applied in the estimation of the rate of greenhouse gas emissions, carries a high probability of underestimation, while the Tier 3 methodology carries a relatively high probability of overestimation. Therefore, when considering the assignment of permissible rates of emission to local governments, the application of the methodology, i.e. whether one uses Tier 1 or Tier 3, may result in a large difference in the rate of allowable emissions. It is suggested that a method based on the actual volume of traffic would be the most reasonable one with regard to the development of a realistic plan.
6.
2009.07
서비스 종료(열람 제한)
Some sections of the exhaust system to determine the shape of the duct is to suffer the difficulties by space constraints to install new equipment of the environment post-treatment for existing operation of the power plants. In this paper the large duct in flue gas desulfurization equipments of the 500MW coal-fired power plant on the current operation is numerically analyzed from induced draft fan exit to booster up fan inlet section which is in the narrow space of the exhaust system with four times bending and is connected to emergency duct to bypass the exhaust gas on the emergency operation. The procedure and method using computational fluid dynamics are proposed to maintain the stability of the guide vane with the uniform flow and a minimum pressure loss of exhaust gas in the case of normal and emergency operation between the direction of the flow of exhaust gas duct at different.
7.
2009.07
서비스 종료(열람 제한)
This study investigates the standard, duration period and excess mortality of extreme heat using the standardized daily mortality data from 1991 to 2004, establishing a standard threshold Criteria for Heat Health Watch Warning System in Korea. It ultimately aims to provide the guidance in building up Heat Health Watch Warning System for Korea by suggesting the standard to quantify thermal stress from heat. The standard threshold Criteria for Heat Health Watch Warning System for Seoul metropolitan city takes into account both daily maximum temperature and daily maximum heat index(HI) and consists of four phases; caution, extreme caution, danger, and extreme danger. Extreme caution phase and danger phase are used as the advisory and warning of extreme heat, respectively. Since the nationwide distribution of the frequency of extreme heat day and the excess mortality rate shows little difference across regions, the standard threshold Criteria for Heat Health Watch Warning System for Seoul metropolitan city can be used for other regions.
8.
2009.07
서비스 종료(열람 제한)
The current standard level of Heat Health Watch Warning System consider both daily maximum temperature and daily maximum heat index(HI), but current standard could not consider daily maximum HI due to the difficulties in forecasting when we consider both daily maximum temperature and daily maximum HI and no considering HI because relative humidity could not observed for some regions. So, Newly established standard level of Heat Health Watch Warning System is based on daily maximum temperature exceeding 30℃ for two consecutive days or daily minimum temperature exceeding 25℃ and daily maximum temperature exceeding 30℃. These days are called "extreme heat days". On extreme heat days, the standard of extreme heat advisory is based on daily maximum temperature among exceeding 32.7℃ and not exceeding 34.8℃, and extreme heat warning is based on daily maximum temperature exceeding 34.8℃. ANOVA analysis was carried out using the data of Seoul Metropolitan City in 1994 to check the robustness of the new standard level of Heat Health Watch Warning System from this study, in particular for mortality variable. The results reveal that the new standard specifies excess mortality well, showing significance level of 0.05 in the difference of excess mortality for each phase.
9.
2009.07
서비스 종료(열람 제한)
To control degradation rate of biodegradable poly(lactide)s (PLA), the stereochemical PLAs with different ratios of d-lactide and l-lactide units were synthesized by the ring open polymerization and the their degradation kinetics were measured by a Langmuir film balance. The alkaline (pH=11) degradation of poly(l-lactide) (l-PLA) monolayer showed the faster rate at a surface pressure of 4 mN/m in the ranges from to 0 to 7 mN/m. However, the enzymatic degradation of l-PLA with Proteinase K did not occur until 4 mN/m. Above a constant surface pressure of 4 mN/m, the degradation rate was increased with a constant surface pressure. These behaviors might be attributed to the difference in the contacted area with degradation medium: alkaline ions need small contact area with l-PLA while enzymes require much bigger one to be activated due to different medium sizes. The stereochmical PLA monolayers showed that the alkaline degradation was increased with their optical impurities while the enzymatic one was inversed. These results could be explained by the decrease of crystallinity with the optical impurity and the inactivity of enzyme to d-LA unit.
10.
2009.07
서비스 종료(열람 제한)
Concentrations of dioxins, furans and dioxin-like polychlorinated biphenyls (DL-PCBs) were determined in crucian carp collected from eight locations mainly along the Nakdong River during 2004. Total dioxin concentrations which include concentrations of dioxins, furans and DL-PCBs ranged from 0.053 to 0.614 pg WHO-TEQ g-1 wet wt. with a mean of 0.342±0.213 pg WHO-TEQ g-1 wet wt. The proportions of dioxins, furans and DL-PCBs to total dioxin TEQ were 4%, 12% and 84%, respectively. The results suggest that concentrations of dioxin-like polychlorinated biphenyls should be determined when total dioxin TEQ accumulated in freshwater fish is investigated.
연구노트
11.
2009.07
서비스 종료(열람 제한)
To determine changes in nitrogen contents and optimal rates as N fertilizer, we investigated nitrogen characteristics in the slurry in the respond to the application of 0, 0.5, and 1 g of ferrous sulfate or alum /25g of dairy slurry. Additions of ferrous sulfate or alum increase total nitrogen, inorganic nitrogen, available nitrogen, and predicted available nitrogen contents in dairy slurry, resulting in reduction in pH. The best results were found in the treatment with 0.5 g of ferrous sulfate or alum /25 g of dairy slurry. In conclusion, the use of ferrous sulfate or alum as on-farm amendment to dairy slurry should be represented an alternative to improve N in dairy slurry.
12.
2009.07
서비스 종료(열람 제한)
The objectives of this study were to evaluate the effects of chemical additives on total phosphorus (TP), soluble reactive phosphorus (SRP), and total volatile fatty acids (total VFAs) in hanwoo slurry. The treatments in this study were ferrous sulfate, alum, and aluminum chloride, and applied at the rate of 0, 0.5, and 1.0 g/25 g of hanwoo slurry. All of the chemical treatments significantly lowered TP (11 to 53% of the untreated control), SRP (41 to 99.9% of the untreated control), and total VFAs (22 to 48.5% of the untreated control) by reducing hanwoo slurry pH (3.42 to 6.86). Among these chemical amendments, addition of 0.5 g ferrous sulfate, alum, and aluminum chloride to hanwoo slurry were the best results evaluated on farms with respect to reducing negative environmental impacts. In conclusion, the results of this study indicate that the use of chemical amendments should be considered in the development of best management practices (BMPs) for the hanwoo industries.
