Experiments were conducted to increase the efficiency of extracting bioactive compounds from Cinnamomum camphora leaves which are industrially used in various fields. Response surface methodology (RSM) maximized the total polyphenol content in extracting C. camphora leaves. The experimental design was conducted for three factors: extraction temperature, ethanol concentration, and solid-liquid ratio. The optimum conditions for the total polyphenol content of C. camphora leave extract were found to be an extraction temperature of 80℃, an ethanol concentration of 55%, and a solid ratio of 100; the predicted value was confirmed to be 57.67 ± 0.66 mg GAE/g. As a result of the experiment, the total polyphenol content of the optimized extract of C. camphora leaves was 57.29 ± 0.41 mg GAE/g, and the total flavonoid content was 10.57 ± 0.20 mg QE/g. The antioxidant activity was also measured at 25.98 ± 0.67 μg/mL for DPPH RC50, higher than the control group BHT (122.69 ± 10.55 μg/mL). TEAC was 239.39 ± 11.28 μM TE/g, and FRAP was 2,049.62 ± 32.45 mM FE/g. Moreover, the inhibitory effect of tyrosinase and Staphylococcus epidermidis was confirmed. The results of this study suggest the optimal conditions for maximum extraction of total polyphenol content from C. camphora leaves, and it is expected to be essential data for industrial use through the physiological activity of optimized extracts.

Aurea helianthus (AH), a representative warm-temperature plant in southern Korea, is traditionally used in China for various medicinal purposes. The bioactive constituents from aerial parts of the AH leaf, stem, and flowers have been studied by several researchers, showing anti-inflammation, immune-modulatory, antioxidant, and whitening effects. However, the effects of the oil extracts of AH flower on the biological activities for antioxidants application have not been thoroughly investigated. This study reported the possible utilization of the oil extracts of AH flower extracts (AHF) and validated the components by GC-MS. The AHF was treated with n-hexane, chloroform, and methanol, respectively. Besides the component analysis of the extract, the antioxidant activities were determined with 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay. The chloroform and methanol extracts showed the highest antioxidant activities and active ingredient contents like the total phenolic and flavonoid contents. GC-MS analysis were determined to be at a maximum in the hexane extracts. In summary, The oil extracts of AHF are helpful as plant resources that can provide good antioxidants and can be used as potential natural healthy food.

Cinnamomum yabunikkei H. Ohba is known as a traditional medicinal plant in Korea. There has been no study done about the lipid compound and biological activity in solvent extracts of C. yabunikkei. In this study, the solvent extract (hexane, chloroform:methanol [2:1, v/v]) of C. yabunikkei leaf, branch, and fruit were investigated for their antioxidant activities and active constituents. The antioxidant properties were evaluated based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ABTS radical scavenging, and lipid peroxidation activity. The branch extract showed the highest DPPH, ABTS, and lipid peroxidation. Antioxidant active substances present in the solvent extract of C. yabunikkei have been analyzed by GC-MS. In summary, C. yabunikkei solvent extracts could be used as a potential natural cosmetic ingredient.

For redundant serial robots, an in-depth analysis is made on the geometric relationship among their velocity ellipsoids, which vary depending on the number of redundant inputs. Such an analysis leads to an overall grasp of how the performance of a serial robot changes across the entire output space due to the introduction of redundancy. First, the velocity ellipsoid of a redundant serial robot is obtained as the range of outputs, mapped from the unit sphere in the input space, and the geometric shape of the velocity ellipsoid is fully described. Second, the condition for which contact occurs among the velocity ellipsoids is derived from redundant inputs. The inclusion relationship among the velocity ellipsoids is systematically identified based on the conversion of the input space constraints into the output space constraints. Third, the case study of two and three DOF serial robots is presented with the simulation results to illustrate the inclusion relationship among the velocity ellipsoids of redundant serial robots.

This paper presented a method for evaluating V2G load curves by using the charging and discharging locations of electric vehicles to evaluate the impact of loads generated by the charging and discharging of electric vehicles on the power grid. Considering the estimated EVs' share, the EVs' discharge power was evaluated to reflect both the nature of the arriving vehicle in the morning and the SMP plan after establishing an assumption that the electric vehicle arrived at work in the morning and the electric vehicle arrived at home in the afternoon for each of the charging/discharging place, which is the work and home of electric vehicles in the city. After evaluating the V2G load for each charging/discharging power type for the EVs charging strategy, which takes into account both the natures of the vehicle arriving at home in the afternoon, the TOU charge system, and the characteristics of the vehicle arriving at work in the morning and the SMP charge system, it was evaluated by comparing the impact assessment on the grid by adding the existing load. The results of this paper provide an accurate understanding of the impact of EVs' charging and discharging loads on the power grid. The results should support establishing an EV charging and discharging load management program to control power grids overload with appropriate SMP and TOU charges.

The use of fossil fuels has caused global warming, and abnormal climates are occurring worldwide. Various studies are being conducted on wind turbine and small hydropower generation, but relatively little research is being conducted on small hydropower generation. Gravitational water vortex turbine, a small hydropower generation type, has a relatively small environmental impact compared to other renewable energy fields. This paper verifies the stability through natural frequency mode analysis and structure analysis to apply the C-rotor type design method to the gravitational water vortex turbine among the vertical axis wind turbines being newly studied in wind turbines.

In this study, FLOW-3D's Forchheimer's saturation drag model was used to physically reproduce the flow of infiltrating water in the body of the permeable seawall. This study confirmed that Forchheimer's saturation drag model could be applied to the permeability evaluation of the sea wall. The flow patterns in the body were compared between the temporary seawall constructed using only rubble stones and the back reinforced seawall in which the back part of the seawall was reinforced with filter rocks and mats. The flow patterns in the temporary seawall body were well-reproduced, in which the infiltration water moves from the open sea to the inside, and the flow accelerates as the stream tube shrinks. In the back-reinforced seawall, the flow pattern in which the seepage line of the body rises compared to the temporary seawall is well-reproduced due to the low permeability of the filter mat. When the simulated results of the inland tide surrounded by the seawall were compared with the observation data, the simulated and observed values showed a slight difference within 0.3m. At the T5 point, seawater exchange through the seawall was relatively as large as the temporary seawall installed. The simulation results reproduced the phenomenon that the tidal wave occurred smaller than the T5 point because the seawater exchange rate through the seawall was relatively low at the T6 point. After all, the back-reinforced seawall was smaller. In addition, it reproduced the observation data in which the tide was delayed, and the duration of the ebb tide was superior to that of the flood tide.

All-ceramic zirconia implant has significant attention as a substitute for titanium implant because of its excellent aesthetic properties and biocompatibility, but it requires improved bioinertness and surface smoothness. This study attempted to improve the bioactivity and surface roughness of zirconia substrate by bioactive wollastonite coating. A continuous process for slurry preparation, spin coating, and post-sintering was used to modify porous zirconia substrate and controlled the repeated coating times and chemical composition. Wollastonite slurry for coating controlled the solid loading, pH, and dispersant to adjust the slurry viscosity. A dense coating layer was obtained by slurry coating and post-sintering processes. The coated layer's microstructural evolution, phase composition, and surface roughness were observed by SEM and XRD investigation, indicating that the coated layer's physical and biological properties depended on the slurry condition and coating times. The coating surface had good bioactivity compared with pure zirconia substrate, indicating that slurry coating of wollastonite was available to enhance the bioactivity of bioinert-zirconia substrate.