Characteristics of hemp radiation field on typical transport aircraft with frequency sweep method

This paper presents characteristics of the HEMP radiation field on a typical transport aircraft using the frequency sweep method. Firstly, the characteristics of the HEMP field are analyzed. Then, various parameters including the electric field strength and magnetic field strength distribution are calculated using Altair FEKO software. Afterwards, the electric field strength distributions of three layers (top layer, inner layer and bottom layer) are calculated and analyzed. The results indicate that the HEMP induced field is affected by the aircraft body. The induced electric field strength E(t) varies greatly at different positions. Nevertheless, the peak value of E(t) is usually greater than the initial peak value of electric field strength E$_{0}$. Such a study can provide guidance and insight into the protection design of the HEMP of the aircraft

Data-Driven Machine Learning for Fault Detection and Diagnosis in Nuclear Power Plants: A Review

Data-driven machine learning (DDML) methods for the fault diagnosis and detection (FDD) in the nuclear power plant (NPP) are of emerging interest in the recent years. However, there still lacks research on comprehensive reviewing the state-of-the-art progress on the DDML for the FDD in the NPP. In this review, the classifications, principles, and characteristics of the DDML are firstly introduced, which include the supervised learning type, unsupervised learning type, and so on. Then, the latest applications of the DDML for the FDD, which consist of the reactor system, reactor component, and reactor condition monitoring are illustrated, which can better predict the NPP behaviors. Lastly, the future development of the DDML for the FDD in the NPP is concluded

Evaluation on coupling of wall boiling and population balance models for vertical gas-liquid Subcooled boiling flow of first loop of nuclear power plant

An accurate prediction of the interphase behaviors of the vertical gas-liquid subcooled boiling flow is meaningful for the first loop of a nuclear power plant (NPP). Therefore, the interphase behaviors including the bubble size distribution in the first loop of the NPP are analyzed, evaluated, and validated using various wall boiling models coupled with the population balance model (PBM) kernels in this paper. Firstly, nondimensional numbers of the first loop of the NPP and DEBORA (Development of Borehole Seals for High-Level Radioactive Waste) experiment test cases are analyzed with approximation. Secondly, five active nucleation site density models N$_{n}$ coupled with the PBM kernel combination, four kernel combinations (C1~C4) with the N$_{n}$ models are calculated and analyzed. Lastly, various behaviors including the bubble size distribution Sauter mean diameter (SMD) d$_{p}$, void fraction α, gas superficial velocity j$_{g}$, and liquid superficial velocity j$_{i}$ are compared and validated with the experimental data of the DEBORA-1 (P = 2.62 MPa). The results indicate that the two Nn models are suitable for the calculations of thefirst loop of the nuclear power plant. For instance, for the bubble size distribution SMD d$_{p}$, the specified N$_{n}$ model with C1 (maximum relative error 9.63%) has relatively better behaviors for the first loop of the NPP. Especially, the combination C1 is applicable for the calculation of the bubble size distribution d$_{p}$, void fraction α and liquid superficial velocity j$_{i}$ while C4 is suitable for the calculation of the gas superficial velocity j$_{g}$. These results can provide guidance for the numerical computation of the subcooled boiling flow in the first loop of the NPP

Latest Study on the Relationship between Pathological Process of Inflammatory Injury and the Syndrome of Spleen Deficiency and Fluid Retention in Alzheimer’s Disease

Inflammation exists throughout the incidence and progression of Alzheimer’s disease (AD). Traditional Chinese medicine (TCM) differentiates the pathogenesis of AD as kidney essence deficiency and qi and blood deficiency as well as blood stasis in syndromes, whose action mechanisms are all associated with the intervention in its inflammatory process. Our preliminary studies both in clinic and in vitro have demonstrated that the syndrome of spleen deficiency and fluid retention has also been an important pathogenesis for the incidence and development of AD. Hence, the paper aims to further illustrate the correlation between inflammatory process in AD and the syndrome of spleen deficiency and fluid retention, laying solid foundation for the application of invigorating the spleen and eliminating the dampness in clinic, and enriching the theoretical connotation for AD prevention and treatment in TCM

Evaluation on Coupling of Wall Boiling and Population Balance Models for Vertical Gas-Liquid Subcooled Boiling Flow of First Loop of Nuclear Power Plant

An accurate prediction of the interphase behaviors of the vertical gas-liquid subcooled boiling flow is meaningful for the first loop of a nuclear power plant (NPP). Therefore, the interphase behaviors including the bubble size distribution in the first loop of the NPP are analyzed, evaluated, and validated using various wall boiling models coupled with the population balance model (PBM) kernels in this paper. Firstly, nondimensional numbers of the first loop of the NPP and DEBORA (Development of Borehole Seals for High-Level Radioactive Waste) experiment test cases are analyzed with approximation. Secondly, five active nucleation site density models Nn coupled with the PBM kernel combination, four kernel combinations (C1~C4) with the Nn models are calculated and analyzed. Lastly, various behaviors including the bubble size distribution Sauter mean diameter (SMD) dp, void fraction α, gas superficial velocity jg, and liquid superficial velocity jl are compared and validated with the experimental data of the DEBORA-1 (P = 2.62 MPa). The results indicate that the two Nn models are suitable for the calculations of thefirst loop of the nuclear power plant. For instance, for the bubble size distribution SMD dp, the specified Nn model with C1 (maximum relative error 9.63%) has relatively better behaviors for the first loop of the NPP. Especially, the combination C1 is applicable for the calculation of the bubble size distribution dp, void fraction α and liquid superficial velocity jl while C4 is suitable for the calculation of the gas superficial velocity jg. These results can provide guidance for the numerical computation of the subcooled boiling flow in the first loop of the NPP

Tribological Properties of Blocky Composites with Carbon Nanotubes

A large amount of primary energy is lost due to friction, and the study of new additive materials to improve friction performance is in line with the concept of low carbon. Carbon nanotubes (CNTs) have advantages in drag reduction and wear resistance with their hollow structure and self-lubricating properties. This review investigated the mechanism of improving friction properties of blocky composites (including polymer, metal, and ceramic-based composites) with CNTs’ incorporation. The characteristic tubular structure and the carbon film make low wear rate and friction coefficient on the surface. In addition, the effect of CNTs’ aggregation and interfacial bond strength on the wear resistance was analyzed. Within an appropriate concentration range of CNTs, the blocky composites exhibit better wear resistance properties. Based on the differences in drag reduction and wear resistance in different materials and preparation methods, further research directions of CNTs have been suggested

Study on the Synthesis and Properties of Biodegradable Poly(butylene diglycolate) Polyester

With increasing environmental requirements, biodegradable polymers have received widespread attention. Herein, we synthesized a series of poly(butylene diglycolate)s (PBDs), which was a novel biodegradable homopolyester, with number-average molecular weight (Mn) values between 13 and 97 K g·mol–1. The effects of Mn on the thermal and tensile properties of PBDs were comprehensively investigated. The glass transition temperature (Tg), melting temperature (Tm), and temperature of 5% weight loss (Td,5%) of PBDs were found to be approximately −26.4, 64.0, and 336 °C, respectively. PBD with 31 K g·mol–1 exhibits a brittle fracture feature, while obvious yielding behavior occurs when the Mn of PBD is higher than 45 K g·mol–1. Besides, PBD achieves stable mechanical properties when Mn reaches 51 K g·mol–1, with the elastic modulus, tensile strength, and elongation at break of 285, 27.1 MPa, and 290%, respectively, superior to those of linear low-density polyethylene (LLDPE). Furthermore, the crystal structures of PBD were recorded by WAXD and POM. The spherulites were observed after isothermal crystallization of PBD in a wide temperature range, and the maximum nucleation density was obtained after annealing at 20 °C. Significant hydrolysis of PBD in both buffer solution and artificial seawater was confirmed by monitoring the changes in residual weight, intrinsic viscosity, surface morphology, crystallinity, and chemical composition. Finally, PBD exhibits considerable biodegradability under composting and freshwater environments, with the residual weight reducing to 49.2 and 94.7% after 35 days, respectively. Due to the balanced mechanical and barrier properties and biodegradability, PBD has potential application prospects in packaging materials