ALBERT

Description: Prediction of sloshing loads, which is one of the most important issues in the design of LNG carriers, has usually been carried out by experiments. When designing a 6-DOF platform equipment used for sloshing experiments, it should target a system containing a fluid, not a solid, thereby making it difficult to predict precisely the dynamic load due to the changes of a center of mass according to the tank’s movement. In the present study, two-way co-simulation technology between DualSPHysics and RecurDyn has been developed to analyze the mechanical behavior in multi-body system coupled with fluid motion; in which DualSPHysics is an open-source code based on particle method for fluid analysis and RecurDyn a commercial software for multi-flexible-body dynamics (MFBD). The developed technology was applied to the sloshing problem inside a tank connected to an upper plate on a 6-DOF platform. The simulation results were verified through comparison with the experiments conducted for this study independently, such as snapshots of flow motion, pressure on the cargo hold, and force applied to the tank-platform connection. Finally, to investigate the effects of fluid dynamic load on structural safety assessment, a two-way co-simulation between fluid-MFBD analysis was performed for two cases filling partially with fluid and solid. As a result, it was concluded that the sloshing experiment system used in this study was quite safe, and the feasibility of using the present co-simulation technology for structural safety assessment was confirmed.

Description: The Korean bottled water market has continuously expanded during the last 25 years. However, in-depth studies of its geochemistry have not been conducted. Four types of bottled water manufactured in South Korea (i.e., natural mineral water, NMW; functional water, FW; carbonated water, CW; and desalinated seawater, DSW) were investigated to classify the water type, verify the accuracy of the ion contents detailed on the bottle labels, and decipher the origin of the water sources using major and trace elements and their isotopes. The waters was classified into three types: Ca-HCO3, Ca(Mg)-Cl, and Na-HCO3. NMW and FW are mainly of the Ca-HCO3 type. Our findings indicate that Korean bottled water chemistry is associated with lithological features and manufacturing processes; NMW is closely related to lithology while FW and DSW are strongly affected by manufacturing processes. Unlike major ions, trace elements cannot be used to decipher Korean bottled water chemistry because they show little apparent relationship with lithology. Regardless of the water chemistry, typical isotopic signals corresponding to intrinsic water were observed in all of the samples, indicating that groundwater and seawater were the sources of Korean bottled water.

Description: Filtration is commonly used to separate liquids from solid materials before the determination of trace element concentrations in aqueous solutions. Therefore, it is important to determine how much elemental content is extracted from the filter itself or lost via absorption into the filter. In this study, we investigated three types of disposable syringe filters (polyvinylidene difluoride, PVDF; polytetrafluoroethylene, PTFE; PTFE with glass microfiber prefiltration media, GD/X) and their acid-cleaned versions using ammonium nitrate (NH4NO3) and acetic acid (HOAc) solutions. The concentrations of most trace elements (Li, Al, Cr, Mn, Co, Ni, Cu, Zn, Rb, Sr, Mo, Cd, Cs, Ba, Pb, and U) were higher in filtrates that had passed through acid-cleaned filters than those that had passed through uncleaned filters. In filtrates from PVDF and PTFE filters, many trace elements were below the detection limit. However, regardless of the filter type and acid cleaning, Li, Cu, Zn, Mo, and Ba concentrations in filtrates of NH4NO3 solutions, and Al, Cr, Mn, Cu, Zn, and Ba concentrations in filtrates of HOAc solutions were much higher than those of other trace elements. These differences were particularly noticeable in filtrates from GD/X filters containing glass microfiber layers. These data indicate that certain trace elements can be released from membrane materials by reacting with acid in the filtered solution. Furthermore, the amounts of each trace element were associated with the membrane type. These findings suggest that filter type should be carefully selected to obtain the required accuracy, in consideration of the target elements and whether an acid-cleaned filter is needed.