Effects of thyroxine and thiourea on the metamorphosis of coral trout grouper Plectropomus leopardus

The contribution of the thyroid hormone to the metamorphosis of the coral trout Plectropomus leopardus was examined. Juveniles, aged 35 days, were exposed to thyroxine (T4, 0.1 p.p.m) and thiourea (TU; inhibitor of thyroid hormone synthesis, 30 p.p.m) for 13 days. All the fish in the T4-treated group had completed metamorphosis (second metamorphosis, pigmentation and resorption of fin spines) within three days after the beginning of the experiment (day 3), whereas it took 13 days for this to occur in the control fish. Moreover, the fish in the TU group had not completed metamorphosis even by day 13. Settling behavior was significantly stimulated by T4 treatment, as was the resorption of the dorsal and pelvic fin spines, the reduction of serration on the spines, and the transition of body color into an opaque reddish hue. Fish in the TU group had longer dorsal and pelvic spines, retarded pigmentation and an abnormal black coloration. These results suggest that thyroid hormone accelerates most changes during the second metamorphosis in the coral trout.     

Development of Novel Water-extraction System with Thermoelectric Module Using Solar and Wind Power in Arid Land

This study aimed to develop a water-extraction system which could produce the fresh water from the air in arid regions and which used renewable energies as the electric power source. In this paper, the experiments for water extraction from the air were carried out by using the novel multi-stage water-extraction device with Peltier deices for two cases of temperature and related humidity of the air. One was the case where the temperature and the related humidity of the air were constant, and the other was the case where they were simulated the variation of the temperature and related humidity of the air in a day of summer and spring in Loess Plateau, China. The effects of the temperature and related humidity of the atmospheric air and supply the electric power to Peltier devices on performance of water production of the device were investigated and reported.     

圆台型聚风罩对垂直轴风力机起动性的影响

为提高直线翼垂直轴风力机自起动性能,设计可安装在风轮上下两端圆台型聚风罩,收集更大面积来流提高来流风速。针对聚风罩高度、倾角及距风轮距离等主要结构参数作二次正交旋转组合设计,利用三维数值模拟方法计算不同聚风罩结构参数条件下风力机起动力矩,对比分析优化聚风罩结构参数,可有效提升风力机起动力矩。通过分析聚风罩与风轮间流场变化,揭示聚风罩对风力机起动力矩影响机理。     

Precocious development of the digestive system in relation to early appearance of piscivory in striped bonito Sarda orientalis larvae

ABSTRACT: Striped bonito Sarda orientalis larvae and juveniles were reared in a laboratory from hatching to 14 days post hatching, and the development of their digestive system was investigated histologically. On day 2 (first feeding day), the larval-type digestive system was differentiated. On day 3, a blind sac with densely distributed gastric glands developed and pyloric ceca appeared, suggesting that the digestive system was attaining adult-type structure. The yolk was completely absorbed on day 4. Bonito larvae preyed on rotifers and/or Artemia nauplii on day 2, but almost the whole gut was occupied by fish larvae from day 4. In the striped bonito, the adult-type digestive system was established right after first feeding, and this precocious development was well synchronized with the appearance of piscivory.     

A wind tunnel experiment of self-starting capability for straight-bladed vertical axis wind turbine

In this study, wind tunnel experiment has carried out to investigate the self staring capability for straight bladed vertical axis wind turbine. The flow visualization has also been performed at the rest of the rotor. The effect of the azimuthal angle of blade position relative to wind direction on the self starting capability was discussed based on the results of flow visualization. The torque and the centripetal force of the rotor when the self starting behavior starts were roughly calculated by using the result of flow visualization of the rotor. It was suggested that there exist the condition of wind speed and configuration of the blade position of the rotor at the rest of rotor to the reach to situational rotation number.