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
제14권 제1호 (2005년 1월) 12건
1.
2005.01
서비스 종료(열람 제한)
CFD code are used for numerically testing a new concept of large space air control system. A workshop with air-conditioners products lines and air-conditioned by several floor type air-containers is tested. The whole room air distribution is controlled by boosters installed in a middle height horizontal plane. First, calculated results are compared with measured data to confirm the validity and applicability of the prediction method. Next, the method is applied to case studies heating seasons. Results under some operating conditions show effectiveness in avoid the temperature stratification in winter.
2.
2005.01
서비스 종료(열람 제한)
This study evaluated the hazard caused by NO2, an oxidant generated in the process of welding. We compared hematological and biochemical parameters in workers who chronically inhale NO2 and office workers not exposed to NO2. NO2 exposure affected the hematological and biochemical parameters. Increasing NO2 concentrationincreased the number of leukocytes, while decreasing the number of erythrocytes. Blood urea nitrogen, creatinine, uric acid, and lactate dehydrogenase were increased, while total protein and triglycerides were decreased. The mean concentration of NOx(NO2-/ NO3-) in the serum of welders and the control group was 35.97±2.85 and 55.40±5.81 μmol/L, respectively. The difference was significant (p<0.05), although NO2- was not detected in the serum.
3.
2005.01
서비스 종료(열람 제한)
Natural gas possesses several characteristics that make it desirable as an engine fuel ; 1)lower production cost, 2)abundant commodity and 3)cleaner energy source than gasoline.
Due to the physics characteristics of natural gas, the volumetric efficiency and flame speed of a natural gas engine are lower than those of a gasoline engine, which results in a power loss of 10-20% when compared to a normal gasoline engine.
This paper describes the results of a research to improve the performance of a natural gas engine through the modification and controls of compression ratio, air/fuel ratio, spark advance and supercharging and method of measuring flame propagation velocity. It emphasizes how to improve the power characteristics of a natural gas engine. Combustion characteristics are also studied using an ion probe. The ion probe is applied to measure flame speed of gasoline and methane fuels to confirm the performance improvement of natural gas engine combustion characteristics.
4.
2005.01
서비스 종료(열람 제한)
Surface sediments (0~4 cm) were sampled at 40 stations from Ulsan Bay and its adjacent areas of Korea, to evaluate the contamination by sewage-derived organic matters using fecal sterols. Some sterols were quantified by gas chromatography coupled to mass spectrometry (GC/MS). Total concentrations of eight sterols (coprostanol, cholesterol, cholestanol, epicholestanol, epicoprostanol, β-sitosterol, brassicasterol, and stigmasterol) in the sediments from Ulsan Bay and its vicinity varied from 929 to 23,444 ng/g dry weight. The most predominant sterols were cholesterol and coprostanol, accounting for 33~72% of total sterols. The concentration of coprostanol known as the indicator of human feces ranged from 141 to 8,257 ng/g dry weight. In particular, the coprostanol concentrations in the sediments from Jansaengpo Harbor and Taehwa River exceeded the value of 1,000 ng/g dry weight, suggesting that these areas could be considered as the hot-spot zones by municipal sewage contamination. Some molecular indices and multivariate data analysis were used to assess the origin of these sterols in the sediments. Results showed that the major routes of sewage contamination in Ulsan Bay and its vicinity were the input through Jansaengpo Harbor and Taehwa River.
5.
2005.01
서비스 종료(열람 제한)
The size of minimum order stream has a very sensitive effect on runoff analysis model using the divergence characteristic of stream. Therefore, in this study, the threshold area of minimum order stream has been examined the change characteristic of topographical parameters. The subject basin of the research was the upper basin of the Kumho water gage station which is located in the middle of the Kumho river. The 1:25,000 numerical geography which was constructed 10×10m mesh was used. The range of investigation of topographical parameters are number of stream order, length, area, slope, basin relief, sinuosity ratio, drainage density and total stream length etc. It was found from the result of analysis that the threshold value of minimum order stream has a very big effect on topographical parameters of basin. It was found that the threshold area of minimum order stream revealed under 0.10km2. Furthermore, the parameters showed a serious change except for over 0.10km2.
6.
2005.01
서비스 종료(열람 제한)
Using three-dimensional non-hydrostatical numerical model with one way double nesting technique, atmospheric circulation in the mountainous coastal region in summer was investigated from August 13 through 15, 1995. During the day, synoptic westerly wind blows over Mt. Mishrung in the west of a coastal city, Sokcho toward the East Sea, while simultaneously, easterly upslope wind combined with both valley wind from plain (coast) toward mountain and sea-breeze from sea toward inland coast blows toward the top of the mountain. Two different directional wind systems confront each other in the mid of eastern slope of the mountain and the upslope wind goes up to the height over 2 km, becoming an easterly return flow in the upper level over the sea and making sea-breeze front with two kinds of sea-breeze circulations of a small one in the coast and a large one in the open sea. Convective boundary layer is developed with a thickness of about 1km over the ground in the upwind side of the mountain in the west and a thickness of thermal internal boundary layer from the coast along the eastern slope of the mountain is only confined to less than 200 m. On the other hand, after sunset, no prohibition of upslope wind generated during the day and downward wind combined with mountain wind from mountain towardplain and land-breeze from land toward under nocturnal radiative cooling of the ground surfaces should intensify westerly downslope wind, resulting in the formation of wind storm. As the wind storm moving down along the eastern slop causes the development of internal gravity waves with hydraulic jump motion in the coast, bounding up toward the upper level of the coastal sea, atmospheric circulation with both onshore and offshore winds like sea-breeze circulation forms in the coastal sea within 70 km until midnight and after that, westerly wind prevails in the coast and open seas.
7.
2005.01
서비스 종료(열람 제한)
8.
2005.01
서비스 종료(열람 제한)
Adsorption characteristics of toluene vapor, which is one of important source of volatile organic compounds (VOCs), by activated carbon were investigated using a fixed bed adsorption column. The operating parameters such as breakthrough curve, adsorption capacity, mass transfer zone (MTZ), and length of unused bed (LUB) were studied. The experimental results showed that the breakthrough time decreased with increasing inlet toluene concentration and gas flow rate. MTZ and LUB increased with the increase of inlet concentration, gas flow rate, and particle size of activated carbon. The adsorption capacity increased with the increase of inlet toluene concentration, while it decreased with increasing particle size. However, it was kept at constant value regardless of the increase of gas flow rate. Adsorption isotherm of toluene vapor could be represented by the Freundlich adsorption equation fairly well. From the adsorption experiments using some VOC gases such as toluene, xylene, butyl acetate. butanol and acetone, it was also found that the adsorption capacity was higher in the case of gas with higher boiling point and lower vapor pressure.
9.
2005.01
서비스 종료(열람 제한)
Soil is one of the most fundamental elements as well as with water and air in studies associated with the environment, in addition, it is one of the important environmental mediums that constructs a basis of the biological system and performs various roles of matter circulation.
This study was carried out in Seoul, in May 2000 to evaluate variation in the concentration levels and distribution characteristics for PAH compounds in soil. Soil samples were collected from 33 sites covering traffic, factory, incineration and mountain groups and the PAHs were analyzed. The results show a wide distribution range of PAHs concentrations between 14.66 ng/g and 1,219.35 ng/g. The highest concentration levels exist at Sungsu-2 of the factory group (FS-2). Daemo-3 of the Mountain group (MD-3) presents the lowest levels as compared with the other sites. PAH compounds including mutagenic and carcinogenic materials show high concentrations in the traffic and factory groups and a high ratio in the mountain group. Besides, these compounds absorbed with micro particles might be spread out over a wide region associated with particles' movement and diffusion.
After principal component analysis of the soil samples, the results indicated that the sources of PAHs in the soil were divided into two groups, pesticides and vehicles.
10.
2005.01
서비스 종료(열람 제한)
As a typical example of simultaneous analysis of the odorous compounds, the volatile organic compounds from inventory sources in Seongseo industrial area were concentrated and analyzed with thermal desorber/GC/ MSD, and major malodorous compounds were estimated. Odor intensity and odor concentration was analyzed simultaneously During a period from November in 2002 to December in 2003, this study was conducted to evaluate malodor emission characterization in major treatment facilities. The major components were Dimethyl sulfide, Dimethyl disulfide, Methyl mercaptane, Ammonia, Benzene, Toluene, m,p-xylene, o-xylene, Styrene, 1,2,4- T.M.B and 1,3,5-T.M.B. Among the six major inventory sources, the odor unit concentration of Night-soil disposal facilities was the highest, 669～2344 ou/m3.
11.
2005.01
서비스 종료(열람 제한)
Several samplers using gravimetric methods such as high-volume air sampler, MiniVol portable sampler, personal environmental monitor(PEM) and cyclone were applied to determine the concentrations of fine particles in atmospheric condition. Comparative evaluation between high-volume air sampler and MiniVol portable sampler for PM10, and between MiniVol portable sampler and PEM was undertaken from June, 2003 to January 2004. Simultaneously, meteorological conditions such as wind speed, wind direction, relative humidity and temperature was measured to check the factors affecting the concentrations of fine particles. In addition, particle concentrations by cyclone with an aerodynamic diameter of 4 ㎛ were measured. Correlation coefficient between high- volume air sampler and portable air sampler for PM10 was 0.79 (p<0.001). However, the mean concentration for PM10 by high-volume air sampler was significantly higher than that by MiniVol portable sampler (p=0.018). Correlation coefficient between Minivol portable sampler and PEM for PM2.5 was 0.74 (p<0.001), and the measured mean concentrations for PM2.5 did not show significant difference. Difference of the measured concentrations of fine particle might be explained by wind speed and humidity among meteorological conditions. Particle concentration differences by measurement samplers were proportional to the wind speed, but inversely proportional to the relative humidity, though it was not a significant correlation.
12.
2005.01
서비스 종료(열람 제한)
Because of the toxicity of hexavelant chromium ion, treatments of metallic surface with chromate compounds to retard corrosion are undesirable for safety control in industrial uses and protection of environment. In this study, we investigated several compounds such as inorganic, organic, and polymer materials in order to substitute the chromate conversion treatment on steel sheet. The corrosion property was investigated in a salt spray tester with 3.5 wt.% NaCl at 35℃. The results showed that the zirconium/silane/polymer triple coatings on the galvanized steel exhibited a significant retardation of corrosion. Although the multicoating system needs a complexed processing, we can confirm a possibility of development of a chromate-free chemical conversion treatment for galvanized steel sheet.
