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As high-temperature-resistant inorganic fibers, Al 2 O 3 fibers possess high-temperature resistance, high-temperature oxidation resistance, and chemical stability, and thus are suitable for applications such as high temperature catalysis and filtration. However, their shortcomings, such as high brittleness and high fracturability, limit their applications. In this study, a flexible Al 2 O 3 /aramid composite felt was prepared by introducing aramid fibers into Al 2 O 3 fiber filaments, and the flexibility of the prepared composite felt was improved by using needle punching. The influence of the Al 2 O 3 /aramid doping ratio on the thermal insulation performance of the composite felt was explored. The findings showed that as the Al 2 O 3 /aramid doping ratio increased, the thermal insulation performance of the composite felt improved, whereas its thermal conductivity decreased. At room temperature of 25 °C and with an Al 2 O 3 /aramid doping ratio of 12:1, the thermal conductivity of the composite felt reached its minimum value of 0.0306 W m−1 K−1, while its compression and fracture moduli became 0.4 MPa and 21.5 GPa, respectively. The thermal-insulation mechanism of the composite felt was also explored in the study. [ABSTRACT FROM AUTHOR]

Low energy consumption has always been one of the core issues in the routing design of underwater sensor networks. Due to the high cost and difficulty of deployment and replacement of current underwater nodes, many underwater applications require the routing protocol design to consider the network lifetime extension problem. Based on this, we designed a new routing protocol that takes into account both low energy consumption and balanced energy consumption, and achieves effective extension of the network lifetime, called adaptive power-controlled depth-based routing protocol for underwater wireless sensor networks (APCDBRP). The protocol consists of two phases: (1) the route establishment phase and (2) the data transmission phase. In the route establishment phase, the initial path is established by the sink node broadcasting beacon packets at the maximum transmission power. The receiving nodes update their routing tables based on the beacon information and forward the beacon packets. In the data transmission phase, APCDBRP introduces a novel forwarding factor that considers both energy efficiency and energy balance. It selects the optimal next hop based on high energy efficiency and relatively abundant energy, thus extending the network's lifetime. Additionally, APCDBRP proposes a new data protection and route reconstruction mechanism to address issues such as network topology changes due to node mobility and data transmission failures. Our simulation is based on AquaSim–Next Generation, which is a specialized tool built on the NS3 platform for researching underwater networks. Simulation results demonstrate that, compared to other typical routing protocols, APCDBRP exhibits superior performance in reducing network energy consumption and extending the network's lifetime. It also achieves a high packet delivery rate with lower energy consumption. [ABSTRACT FROM AUTHOR]

For the channel estimation problem under α-stable distributed impulse interference, the traditional fixed-step adaptive filtering cannot satisfy the fast convergence speed and low steady-state error at the same time, whereas the variable-step method is able to effectively solve this contradiction. This paper proposes an improved variable step-size least mean p-power adaptive algorithm that offers good robustness against impulsive noise. The proposed algorithm takes into account the linkage between the errors and uses the adjustment of the step size based on the errors of the current moment and the previous k moments, thus overcoming the problems of poor anti-noise performance and large steady-state fluctuations of the fixed-step size algorithm. This algorithm ensures that the step size does not change abruptly when the system is disturbed by impulse noise and can achieve a lower steady-state error. The simulation results show that the algorithm has better convergence than the traditional fixed step-size algorithm and the existing variable step-size algorithm under the interference of impulsive noise. [ABSTRACT FROM AUTHOR]