• 한국재료학회지
• /
• 제32권9호
• /
• pp.369-378
• /
• 2022

The recycling of solid waste materials to fabricate carbon-based electrode materials is of great interest for low-cost green supercapacitors. In this study, porous carbon foam (PCF) was prepared from waste floral foam (WFF) as an electrode material for supercapacitors. WFF was directly carbonized at various temperatures of 600, 800, and 1,000 ℃ under an inert atmosphere. The WFF-derived PCF (C-WFF) was found to have a specific surface area of 458.99 m²/g with multi-modal pore structures. The supercapacitive behavior of the prepared C-WFF was evaluated using a three-electrode system in a 6 M KOH aqueous electrolyte. As a result, the prepared C-WFF as an active material showed a high specific capacitance of 206 F/g at 1 A/g, a rate capability of 36.4 % at 20 A/g, a specific power density of 2,500 W/kg at an energy density of 2.68 Wh/kg, and a cycle stability of 99.96 % at 20 A/g after 10,000 cycles. These results indicate that the C-WFF prepared from WFF could be a promising candidate as an electrode material for high-performance green supercapacitors.

• 인간식물환경학회지
• /
• 제22권2호
• /
• pp.159-165
• /
• 2019

The purpose of this study was to examine the effects of repetitive horticultural activities on the dexterity and out of seat behaviors of 5 years old children. Horticultural activities were conducted from March 3 to April 21, 2017, once a week for 20 minutes per session, a total of 8 sessions. The program was divided into first half (Sessions 1-4) and second half (Sessions 5-8) and horticultural activities were repeatedly carried out. In Sessions 1 and 5, kindergarteners transplanted succulent plants into pots, and observed and managed the plants daily. From Session 2 to 4 and from Session 6 to 8, kindergarteners watered and observed the succulent plants planted in Sessions 1 and 5 and they put flowers on a floral foam (10 × 10 × 10 cm). This study conducted the O'Connor Tweezer Dexterity Test in which the number of pins subjects inserted for 30 seconds was counted, and there was a significant difference (p =.000) in the dexterity of the kindergarteners after performing horticultural activities in the result of the repeated measures design ANOVA. The time kindergarteners left their seat for the first time while participating in horticultural activities for 20 minutes was measured using a stopwatch in each session. There was a significant difference (p =.000) in the ANOVA test in changes in their out of seat behavior in Session 8. In addition, there was no significant difference in the dexterity and out of seat behavior of kindergarteners from Session 2 (p =.364, p =.975, respectively) to Session 3 (p =.055, p =.283), but there was a significant difference from Session 4 (p =.042, p =.009) to Session 8 (p =.000, p =.000) as sessions were repeated.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제26권1호
• /
• pp.61-66
• /
• 2013

Baculum elongatum has several peculiarities such as parthenogenesis, unique external features, changing body color, and dropping oviposition, which makes it a potential economically useful insect. Oviposition was performed by females without fertilization by the sperm of males. The oviposition period was $42.2{\pm}22.7$ days and the number of eggs per female was $109.5{\pm}70.5$ eggs. The hatch rate was 73.3% at $25^{\circ}C$ and 66.7% after low temperature treatment ($8^{\circ}C$ for 60 days). In nature, B. elongatum overwinters as an egg, but it can be assumed from the results that cold temperatures were not required for hatching. The hatch rate was 98.2% in the treatment using floral foam, fermented sawdust, and leaves. The developmental period was $100.9{\pm}4.2$ days for eggs, $55.3{\pm}4.6$ days for nymphs, and $49.7{\pm}16.0$ days for adults. The length of the eggs was $0.33{\pm}0.0$ cm and the lengths of the nymphs were clearly distinguishable according to the instar stage. Clover(Trifolium repens) was an excellent diet as it was similar to the host plant and could be used as an alternative diet. The rate of reaching adulthood for the insects was 66.7% on an artificial diet containing 25% acacia leaves. For sustainable mass rearing of nymphs or adults of B. elongatum, a natural diet could be used such as acacia (Robinia pseudoacacia), white oak (Quercus aliena), chestnut (Castanea crenata var. dulcis), and bush clover (Lespedeza bicolor), or an alternative diet such as clover or artificial diet.