We have studied the characteristics of wind over Pusan coastal area in order to precisely predict surface wind having an important effect on oil spill fate using the data on surface observation of Pusan, Kimhae and Gadeogdo island which are collected during the 3 years from 1988 to 1990. We also investigated the correlation of the surface wind between Pusan, Kimhae and Gadeogdo island. In both Pusan areas and Kimhae, the land and sea breeze occurs during the whole season except for winter. The occurrence frequency of land and sea breeze is significantly high from April to August. The correlation of surface wind between Pusan, Kimhae and Gadeogdo island surface wind is high in the daytime. The occurrence frequency of sea breeze in the Kimhae areas is higher than that in pusan on the basis of the present criteria. For monthly occurrence, Pusan has the highest occurrence frequency of the sea breeze in August and Kimhae has in May.
Gernerally, it is difficult to predict water quality in a tidal river, because tidal flows make the transport phenomena more complicated. The purpose of this study is to clarify long-term mass transport in a tidal river through suggestion of simulation model. A simulation model based on a Lagrangian coordinate system, which has the advantage reducing numerical dispersion, was used to calculate changes in concentration of chlorides. Several field surveys were conducted to verify calculated results. Concludingly, long-term behavior of mas transport in a tidal river can be represented using the model.
An one dimensional atmosphere-vegetation interaction model is developed to discuss of the effect of vegetation on heat flux in mesoscale planetary boundary layer. The canopy model was a coupled system of three balance equations of energy, moisture at ground surface and energy state of canopy with three independent variables of T_f(foliage temperature), T_g(ground temperature) and q_g(ground specific humidity). The model was verified by comparative study with OSU1D(Oregon State University One Dimensional Model) proved in HYPEX-MOBHLY experiment. As the result, both vegetation and soil characteristics can be emphasized as an important factor in the analysis of heat flux in the boundary layer. From the numerical experiments, following heat flux characteristics are cleary founded simulation. The larger shielding factor(vegetation) increase of T_f while decrease T_g because vegetation cut solar radiation to ground. Vegetation, the increase of roughness and resistance, increase (f sensible heat flux in foliage while decrease the latent heat flux in the foliage.
The diffusion of the pollutants released into atmosphere is dependent on its chemical reaction, topography and micrometeorological characteristics. The purpose of the study is to investigate how much micrometeorological characteristics such as stability, wind speed and mixing height affect the diffusion of the air pollutants. For this purpose, this paper let 1) the basic theory be K-theory, 2) eddy diffusivity and wind speed be dependent on mixing height and stability, and 3) Crout method be used for numerical calculation. The result was 1) the more unstable condition, the higher mixing height and the higher wind speed are, the lower pollutants concentration appears, 2) the most intensive effect on the distribution of the pollutant concentration is the atmospheric stability.
Dispersion characteristics of air pollutants in the mountainous coastal area are investigated in considering with the mesoscale local circulations using a two dimensional numerical model with two kinds of topograpy of 500m and 300m. In the model, land-sea breezes and mountain-valley wind are mainly considered under the condition of the absence of large scale prevailing flow in the circulation analysis, and the pollutants dispersion is traced by the Lagrangian methods. According to the results, the wind velocity is affected by topography and is stronger in the case of 500m height mountain than that of 300m, the pollutants that source is near the coast transported over the mountain and dispersed to behind inland area. It is classified that the topography change control affects the wind velocity and the circulations. The pollutants that source is different transported and concentrated to behind inland and/or diffused to the sea area by the combination of the wind system with topographic changes. The results can be applied to the air pollution control with the arrangement design of industrial area and the planning of coastal developments.
Effect of the liquid circulation velocity on the biofilm development was investigated in an inverse fluidized bed biofilm reactor(IFBBR). To observe the effect of the influent COD concentration on biofilm simultaneously, the influent COD value was adjusted to 1000㎎/ℓ for 1st reactor, and 2500㎎/ℓ for 2nd reactor. The liquid circulation velocity was adjusted by controlling the initial liquid height. As the liquid circulation velocity was decreased, the settling amount of biomass was increased and the amount of effluent biomass was decreased. Since the friction of liquid was decreased by the decrease of liquid circulation velocity, the biofilm thickness was increased and the biofilm dry density was decreased. In the 1st reactor, the SCOD removal efficiency was constant regardless of the variation of the liquid circulation velocity, but it was increased by the decrease of the liquid circulation velocity because of more biomass population in 2nd reactor.
On the basis of the principle of Bratch`s electronegativity equalization, we calculated group partial charges and group electronegativities for nonionic surfactants with Pauling`s electronegativity parameters by using numerical calculation method. From calculated output, we have investigated structural stability of micelle, characteristics of hydrophilic and hydrophobic groups, and relation between CMC(Critical Micelle Concentraion) and group partial charge and group electronegativity of hydrophilic and hydrophobic groups for nonionic surfactants. We have known that CMC by micelle formation depends upon group partial charge and group electronegativity of hydrophilic and hydrophobic groups for surfactants. Also, the structural stability of micelle in H_2O solution is related to the electric double layer by the hydrophilic group of nonionic surfactants with H atoms in water. CMC is diminished by the decrease of repeating units in hydrophilic group at constant hydrophobic group and is diminished by the increments of alkyl chains in hydrophobic group at constant hydrophilic group for nonionic surfactants. In conclusion, CMC is diminished because there is no electrostatic repulsion and is diminished of Debye length by the increments of partial charge of hydrophobic group.
The regiospecific potential for the reductive dechlorination of 2-, 3-, 4-, 2,3-, 2,4-, and 3,4-chlorophenols (CPs) was studied in mono- and di-CP(DCP) adapted sediment slurries(10% solids). Freshwater sediments adapted to transform 2-CP dechlorinated all tested mono- and di-CPs except 4-CP without a lag period. Adaptation to 2-CP, thus, enhanced the onset of dechlorination of 3-CP and all ortho-substituted CPs tested. Sediment adapted to transform 3-CP dechlorinated all tested CPs, except 4-CP and 2,4-DCP, without a lag period. Sediments adapted lo individual DCPs (2,3-, 2,4-, and 3,4-DCP) exhibited dechlorination (no lag phase) of 2-CP, 2,3-, 2,4-, and 3.4-DCP. Interestingly, meta-cleavage of 3,4-DCP in all tested adapted sediment occurred, while para-cleavage occurred in 3,4-DCP adapted sediment. Sediments adapted to dechlorinate ortho and meta-chlorines exhibited a preference for meta following ortho-cleavage, but not for para-cleavage, while the preference for reductive dechlorination was ortho > meta > para for mono-CPs and ortho > para > meta for DCPs in unadapted freshwater anoxic sediments.