Various efforts have been explored to save the cost in many industrial fields. In order to recover the residual thermal energy from the flue gas, an extreme high efficiency heat exchanger is planning to install at a power plant. The gas temperature will be reduced to 40°C from 115°C. Thus gas buoyancy decreases, and dispersion of nitrogen oxides is expected to deteriorate as increasing relative humidity. In this study, the conversion of nitrogen monoxide to nitrogen dioxide and dispersion regime are investigated through computational modeling. Nitrogen dioxide which indicates 0.1 ppm at 85 m from the ground could be propagated to 620 m at 115°C of the flue gas, whilst when cooled down to 40°C, it expands up to 750 m. The ground level influence area showed more expansion of dispersion, approximately to 930 m.

일반적으로 액체가스운반선은 인화성 화물이나 독성물질을 운반한다. 이러한 화물들은 폭발, 화재 및 인명손상을 가져올 수 있기 때문에, 액체가스운반선의 거주구역, 서비스 구역 및 통제실은 가스의 유입이 원천적으로 차단되도록 설계한다. 이러한 이유로, IMO IGC 코드의 멤브레인형 LNG선박의 화물탱크에 설치되는 벤트 출구의 높이는 노출갑판상 B/3 또는 6m 중 큰 것 이상으로 하고 작업구역 및 전후부 통행로, 갑판상의 저장탱크 및 화물설계 액위보다 6m 이상 높게 설치하여야 한다라고 규정하고 있다. 또한 LNG 시장이 점진적으로 증가하면서, LNG선박의 크기도 증가해 왔다. 때문에 현 규정에 의하면 LNG선박의 벤트의 높이는 선박 폭(B)에 비례하기 때문에 상당히 높아져야 할 것이며, 이는 높은 벤트 마스트(Mast)로 인하여 작업의 어려움 및 전방 시야를 방해하는 등 항해의 어려움을 초래한다. 본 연구에서는 멤브레인형 LNG선의 Sea-trial시에 측정하였던 데이터 및 CFD유동해석을 통해 LNG선박 화물탱크의 벤트 출구의 높이에 대한 적합성 평가를 수행한다.

A numerical simulation of plume from a stack into atmospheric cross flow is investigated using a two-dimension model. The simulation is based on the k~ε turbulence model and a finite volume method. In this paper, it mostly researches how the wind velocity affects the flue gas diffusion from an 80 m high stack. Wind velocity is one of the most important factors for flue gas diffusion. The plume shape size, the injection height, the NO pollutant distribution and the concentration at the near ground are presented with two kinds of wind velocities, 1 m/s and 5 m/s. It is found that large wind velocity is better for flue gas diffusion, it generates less downwash. Although the rise height is lower, the pollutant dilutes faster and more sufficient.

A method of functionalization of multi-walled carbon nanotube (MWNT) at room temperature using dry ozone gas is described. The resulting MWNT were characterized by Fourier transform infrared, x-ray photoelectron spectroscopy, and scanning electron microscopy. Combined to these analyses and solubility in liquids, it could be concluded that the dry ozone gas exposure introduces polar functional groups such as carboxylic groups to MWNT similar to acidic modification of MWNT. Particularly, the stable dispersion of MWNT in water after ozone treatment above a critical level could be obtained, implying potential bio-application. The hydrophilic functional groups on the MWNT introduced by ozone oxidation were helpful in improving the interaction with functional groups in PA6 such as -NH2 and -CONH- resulting in improved mechanical properties.

This paper demonstrates the numerical simulation of three dimensional flow pattern for vehicular exhaust dispersion in the street canyons. The wind flow around buildings in urban is computed by the SIMPLEST method. The convection-diffusion equation was used to compute the NOx concentration level near buildings. Details are given of important boundary conditions and turbulence quantities variations. The simple turbulence model was used for unisotropic viscous effect. A control-volume based finite-difference method with the upwind scheme is employed for discretization equation. The simple turbulence model applied in this study has been verified through comparison between predicted and measured data near buildings. By the predictive results, the updraft induced by the presence of high-rise buildings is important in the transport of street level pollutant out from the street canyons. Our suggestion for reducing ground level pollution is to have high-rise buildings constructed or to reduce the channelling effect of street canyons.