With the development of WSNs in the military and commercial fields, the security of WSNs is becoming more and more important. The security threats of wireless sensor networks (WSNs) come from not only the attacks of external attackers but also the byzantine behaviors and selfish behaviors of internal nodes. The classical security mechanisms, namely cryptography and authentication, can prevent some outsider attacks, however, they are noneffective to the attacks and the anomaly behaviors of internal nodes. A reputation-based model for malicious node detection in WSNs is proposed in this paper. In this model, the beta distribution is used to describe the reputation distribution, and the indirect reliability of third-party nodes is introduced. The simulation results show that the proposed model has better performance in terms of resisting the malicious deceit behaviors of high credit-grade nodes.

Bubble columns are regarded as an effective containment filtration method. A large amount of radioactive aerosol will be retained in a liquid pool and generate decay heat. The surface tension, viscosity and other parameters of the liquid phase are affected by increasing temperature of the liquid pool and the presence of aerosol in the pool, which in turn affect the formation characteristics of bubbles. Another important factor affecting bubble generation characteristics is the proportion of steam in the gas phase, that is, the exchange of mass, and energy of gas phase. This paper will investigate the effects of liquid temperature, aerosol and gas phase composition on bubble formation characteristics by analyzing the variation of bubble detachment volume of the orifice in liquid pool.

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