동조액체감쇠기(TLD)는 에너지 소산장치로써 구조물의 동적응답을 제어하기 위해 개발되었다. TLD는 풍하중에 의한 구조물의 응답을 제어에 매우 효과적임을 보여줬다. 그러나 TLD가 설치된 구조물의 지진응답의 제어에 대해서는 충분한 연구가 이뤄지지 않았다. 이 연구의 목적은 TLD가 설치된 구조물에 여러 동조비와 질량비를 대입하여 지진에 대한 TLD의 성능을 도출하는 것이다. 이러한 목적을 위해, 수치해석 연구가 실시되며, 다른 토양 조건 또한 고려되었다. 그 결과 지진하중에 대한 TLD의 성능은 구조물의 고유주기, 감쇠비에 따라 다르게 나타났다. 또한 TLD의 동조비 다르게 나타남을 알 수 있었다.

Light characteristics are very specific in the aquatic environment. Fish vision and different light spectra perception are related to each species’ natural habit. Light is one of the main environmental conditions and can be easily manipulated in artificial rearing settings. Mucus-secreting goblet cells are the main regulators of digestion. In this study, we established whether the light spectrum (natural condition, full spectrum: green, 520 nm; red, 590 nm, and blue, 480 nm) influences growth performance and digestive activity related to mucus-secreting goblet cell activity in order to develop a good management protocol and optimal rearing system for nursery stage of Epinephelus akaara. For each light spectrum, fish (11.5 ± 0.2 g in mean initial body weight, 9.0 ± 0.1 cm mean initial total length) were reared 16 weeks under a flow-through system and fed commercial pellet diets twice daily. At the end of the experiment, the final body weights differed among the fish reared under different light spectra. The highest growth performance value and feed efficiency were observed in fish reared under the green light condition. Mucus-secreting goblet cell activity was significantly higher in the fish under green light condition than in the fish under the natural, red, and blue light conditions. Rearing of E. akaara under the green light condition had positive effects on fish growth performance and digestion. We recommend that the appropriate light spectrum for nursery stage of E. akaara is the green light condition from the perspective of growth performance and the synergistic effects of mucus-secreting goblet cells. However, longer light treatment periods are needed in future investigations to clarify the effects of light spectrum on each growing stage of E. akaara.

As a preliminary investigation into the effect of environmental factors control for gonadal development, we examined the involvement of photoperiod and water temperature in ovarian development of Epinephelus. akaara. For the induction of sexual maturation, E. akaara reared in recirculating aquaculture system (RAS). During November 2013, the photoperiod and water temperature was adjusted to 12L:12D and 18℃, respectively. In the photo-thermal treatment group, every 3 weeks daylight was increased as follows a 13L:11D and 14L:10D, and control group was maintained under natural condition. After 9 weeks, water temperature was increased 23℃ in photo-thermal treatment group. The sampled fish every 3 weeks revealed increase in gonadosomatic index (GSI; 5.18±1.38), oocyte diameter and vitellogenic oocytes (423.9±36.1 ㎛) were observed in gonads 12 weeks under photo-thermal treatment group. However, ovarian development was maintained immature stage in control group. In this environmental factors manipulation trial, seventy one of the 95 females (578.4 ± 25.4 g in mean body weight, 31.0 ± 0.5 cm mean total length) treated with HCG injection (doses 500 IU/kg BW) were induced ovulation by artificial stripping. The total volume of ovulated eggs were 3,470 ml and the total volume of fertilized eggs was 3,295 ml. The fertilization rate and hatching rate were 95% and 98%, respectively. These results suggest that the photoperiod as well as water temperature are major environmental factors in triggering the gonadal development of E. akaara.