The black soldier fly is economically important because its prepupae are used as feed for many animals, including fish and swine. In Korea, black-soldier-fly farms have attempted to increase annual breeding and mass egg production for use in animal feed, as well as the decomposition of organic waste. Such efforts require an understanding of optimal mating and oviposition techniques. Specifically, adult densities and cage size may both improve the efficiency of mass egg production. Our study used four sizes of nylon cages (1.0 × 1.0 × 2.5 m, 1.5 × 1.5 × 2.5 m, 2.0 × 2.0 × 2.5 m, 2.5 × 2.5 × 2.5 m) and three density treatments (4 kg, 8 kg, and 10 kg of pupae) to investigate optimal habitat size and adult density. We found that cage size (independent of density) did not significantly influence female fecundity (number of egg clutches and egg weight), whereas higher densities increased egg number and weight regardless of cage size. Thus, we recommend manipulating adult density to enhance productivity in commercial black-soldier-fly farming. However, we also propose further detailed research to develop methods that account for seasonal changes and environmental conditions, as climatic variables (temperature, sunlight) likely influence female fecundity as well.

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Recently, vegetable oils have been exploited for the production of bio-based polyol due to their biodegradability, renewability and reasonable prices in comparison with petroleum-based polyol. Cardanol derived from cashew nut shell liquid oil (CNSL) is renewable resource having a reactive aliphatic double bond and phenolic compound that could be used in preparation of the novel functional materials for versatile polymers. Over the years, various derivatives of cardanol have been continuously studied and also cardanol-based polyol has been explored in various application fields of polyurethane. In this study, biopolyol derived from cardanol was prepared using 1,4-dibromobutane (DB) for intermediate, followed by chemical modification with diethanolamine (DEA). The molecular structure of cardanol based polyol was analyzed by 1 H NMR, FTIR and GPC. Biopolyurethane (BPU) film was prepared with hexamethylene diisocyanate (HDI) using dibutyltin dilaurate (DBTDL) as a catalyst. BPU film showed antibacterial property against Escherichia coli (E. coli). Cross-linked BPU film exhibits higher tensile strength and thermal stability than BPU film. This reveals that cardanol-based BPU is a suitable candidate for various applications as an environment-friendly polymeric material.

Article history:Invar is a compound metal of Fe-Ni system contained 36.5% Ni. The characteristic of invar is that the coefficient of thermal expansion is 1.0×10 -6 cm/°C. It is approximately 10 times smaller than series of steel. Because of this low thermal expansion characteristic of Invar, it is used to shadow mask of display device such as UHDTV or OLED TV. In this study, pulse current from pulse generator instead of DC current is used to overcome the disadvantages of the conventional electrochemical machining. Pulsed current with different duty factor in PECM affect the precise geometry. Pulse electrochemical machining is conducted to machine the micro hole to the invar sheet with different duty factor. The machined shape and overcut of invar sheet with different duty factor is observed by optical microscope and scanning electron microscope (SEM). . 또한, 펄스전해가공은 기존