Modification of the surface of raw activated carbon using chemical solvents can significantly improve the adsorption performance of activated carbon. Triethylenetetramine is one of the most important chemical solvents used to modify raw activated carbon for formaldehyde removal indoor. We conducted the liquid impregnation experiments at different initial concentrations, temperatures, adsorbent dosage and time ranges to fully investigate the adsorption of triethylenetetramine on the surface of raw activated carbon for modification. We found that the Langmuir isotherm model and pseudo-first-order kinetic model fit quite well with the experimental data and the R2 are 0.9883 and 0.9954, respectively. The theoretical maximum adsorption capacity is 166.67 mg/g. The change in Gibbs free energy (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0) were also calculated to study the direction and driving force of the liquid adsorption process. In order to understand the adsorption process at the molecular level, a new activated carbon model based on the actual physical and chemical properties of activated carbon was carefully established in the Materials Studio to simulate the liquid-phase adsorption. The pore structure, elemental composition, functional group content, density, pore volume, and porosity of the activated carbon model converge close to the actual activated carbon and the adsorption isotherms obtained from the simulation agree well with the experimental results. The results show that the adsorption of triethylenetetramine on activated carbon is a spontaneous, endothermic and monolayer physical adsorption process.

Organic waste generated by small and medium-sized (S&M-sized) metal decontamination in NPP decommissioning. To lower the concentration of these organic substances for a level acceptable at the disposal site, the project of “Development of Treatment Process of Organic Decontamination Liquid Wastes from Decommissioning of Nuclear Power Plants” is being carried out. The conditioning and treatment process of organic liquid waste was designed. Also, the literature was investigated to make simulated organic liquid waste, and the composition of these waste was analyzed and compared. As the decontamination agent, organic acids such as EDTA, oxalic acid, citric acid are used. The sum of the concentrations of these organic materials was set to a maximum value of 1,000 ppm. The major metal ions of the decontamination liquid waste estimated are 59Fe, 51Cr, 54Mn, 63Ni, and the concentrations are respectively 527, 163, 161, 159 ppm. Additional major metal ions are 60Co, 58Co, 137Cs. 58Co is replaced by 60Co because it has the same chemical properties as 60Co. Unlike the HLW, the contamination level of S&M-sized metal in primary system was quite low, so 60Co is set to 2,000 Bq/g. Considering the contribution of fission and gamma ray dose constant, 137Cs was estimated to 360 Bq/g. Also, suspended solids of decontamination liquid waste were set at 500 ppm. Under these assumptions, the simulated organic liquid waste was made, and then organic substances and metal ions were analyzed with TOC analyzer and ICP-OES. The TOC analysis value was expected to 392 ppm in consideration of the equivalent organic quantity. the test result was 302 ppm. Some of organics appears to have been decomposed by acid. The values of metal ions (Fe3+, Cr3+, Mn2+, Ni2+) analyzed by ICP-OES are 139, 4, 152, 158 ppm, respectively. A large amount of Cr3+ and Fe3+ were expected to exist as ions, but they existed in the form of suspended solid. Mn2+ and Ni2+ came out similar to the expected values. The designed conditioning and treatment process is largely divided into pretreatment, conditioning, and decomposition processes. After collecting in the primary liquid waste storage tank, large particulate impurities and suspensions are removed through a pretreatment process. In the conditioning process, treated liquid waste passes through UF/RO membrane system, and pure water is discharged to the environment after monitoring. Concentrated water is decomposed in the electrochemical catalyst decomposition process, then this water secondarily passes through the RO membrane system and then discharged to the environment after monitoring. Through an additional experiment, the conditioning and treatment process will be verified.

The lattice Boltzmann method (LBM) is applied to study the behavior of liquid droplet inside a PEMFC gas channel. To validate the fluid-fluid interaction model, the relationship between the pressure jump across the interface and the bubble radius is investigated for a static bubble to confirm the Laplace’s law. To evaluate the fluid-solid interaction model, static contact angle is calculated by changing the interaction parameter. Also, a constant gravitational force is applied to study the temporal evolution of liquid droplet placed on the bottom wall in a three dimensional periodic channel.

Numerical simulations of liquid water droplets interacting with gas channel walls in a polymer electrolyte membrane fuel cell are performed with the volume of fluid (VOF) method. To investigate the effect of channel wall wettability, the contact angles of gas diffusion layer (GDL) and the side/top walls are varied as 45, 90, and 140 degrees. Two different water injection inlet locations are selected to investigate the interactions of liquid water with the different gas channel walls. As the GDL contact angle increases, the GDL surface water coverage ratio and the water volume ratio decrease. When the water injection hole is located near the side wall, the GDL surface water coverage ratio decreases and the water volume ratio increases as the contact angle of the side and top walls decreases. In conclusion, the GDL surface water coverage ratio and the water volume ratio may compete with each other to determine the fuel cell performance.

The dynamic interaction of liquid droplets emerging from the gas diffusion layer surface is modeled to study the behavior of liquid water inside the gas channel of a polymer electrolyte membrane fuel cell with the volume of fluid (VOF) formulation. The surface contact angle of gas diffusion layer is varied as 45, 90, and 140 degrees. The air inlet velocity in the gas channel is varied as 5, 10, and 15 m/s. The water inlet velocity from micro pores is varied as 0.5, 1, and 2 m/s. As the contact angle increases, water coverage ratio increases. As the air inlet velocity and the water inlet velocity increase, water droplets move faster toward the channel exit as evidenced from the water front location plots. In summary, the hydrophobic wall contact angle and higher air/water inlet velocities provide better water removal characteristics.

본 연구의 목적은 높이맵 기반의 액체 시뮬레이션을 이용하여 인간 친화적으로 표현하기 위한 감성 컨텐츠 제작 에 있다. 액체를 인간 친화적으로 표현하는 기존 연구들은 액체 표면을 표현하는데 몇 가지 문제점이 있다. 이러한 문 제를 해결하기 위해 본 연구는 액체의 광학적 특징을 이용한 새로운 액체의 카툰 렌더링 기법을 제안한다. 본 연구 에서 제안하는 액체의 카툰 렌더링은 반사와 굴절을 독립적으로 표현한 채색 단계와 액체의 경계선과 파형선을 표현 하는 선화 단계를 거쳐 표현된다. 그 결과 인간 친화적으로 표현된 액체의 표면을 실시간으로 감성 컨텐츠로 제작할 수 있다.