A Cascading Failure Model for Command and Control Networks with Hierarchy Structure

Cascading failures in the command and control networks (C2 networks) could substantially affect the network invulnerability to some extent. In particular, without considering the characteristics of hierarchy structure, it is quite misleading to employ the existing cascading failure models and effectively analyze the invulnerability of C2 networks. Therefore, a novel cascading failure model for command and control networks with hierarchy structure is proposed in this paper. Firstly, a method of defining the node’s initial load in C2 networks based on hierarchy-degree is proposed. By applying the method, the impact of organizational positions and the degree of the node on its initial load could be highlighted. Secondly, a nonuniform adjustable load redistribution strategy (NALR strategy) is put forward in this paper. More specifically, adjusting the redistribution coefficient could allocate the load from failure nodes to the higher and the same level neighboring nodes according to different proportions. It could be demonstrated by simulation results that the robustness of C2 networks against cascading failures could be dramatically improved by adjusting the initial load adjustment coefficient, the tolerance parameter, and the load redistribution coefficient. And finally, comparisons with other relational models are provided to verify the rationality and effectiveness of the model proposed in this paper. Subsequently, the invulnerability of C2 networks could be enhanced

Controllable Preparation of Highly Crystalline Sulfur-Doped Π-Conjugated Polyimide Hollow Nanoshell for Enhanced Photocatalytic Performance

In this study, a series of highly crystalline π-conjugated polyimide photocatalysts with porous nano hollow shell (HSPI) was prepared for the first time by the hard template method by adjusting the addition ratio of the template precursor. SiO2 nanospheres not only serve as template agents but also as dispersants to make precursors of SPI more uniform, and the degree of polymerization will be better, resulting in significantly enhanced crystallinity of HSPI relative to bulk SPI (BSPI). More strikingly, it is found that HSPI has a larger specific surface area, stronger visible light absorption, and higher separation efficiency of photogenerated electron and hole pairs compared with BSPI by various spectral means characterization analysis. These favorable factors significantly enhanced the photocatalytic degradation of methyl orange (MO) by HSPI. This work provides a promising approach for the preparation of cheap, efficient, environmentally friendly, and sustainable photocatalysts

Mechanical and Thermal Properties of PLA Biocomposites Reinforced by Coir Fibers

In this work, polylactic acid (PLA) biocomposites reinforced with short coir fibers were fabricated using a corotating twin-screw extruder and injection molding machine. Short coir fibers were treated by mixed solution including hydrogen peroxide and sodium hydroxide to improve the adhesion between fibers and PLA matrix. The effects of treated coir fiber content (1, 3, 5, and 7 wt%) on tensile, impact, thermal properties, and surface morphology of PLA biocomposites were investigated. The best impact strength results were obtained for 3 wt% PLA/treated coir fiber biocomposites, where the impact strength was increased by approximately 28% compared to the neat PLA. The tensile modulus of PLA biocomposites was increased by increasing the treated coir fiber content. These results were confirmed by morphological structure analysis. Differential scanning calorimetry (DSC) results demonstrated a minor effect of the treated coir fiber on thermal behavior of PLA resin. Thermogravimetry analysis (TGA) demonstrated that the thermal stability of the PLA/treated coir fiber biocomposites was reduced by the incorporation of treated coir fiber

Controllable Preparation of Highly Crystalline Sulfur-Doped Π-Conjugated Polyimide Hollow Nanoshell for Enhanced Photocatalytic Performance

In this study, a series of highly crystalline π-conjugated polyimide photocatalysts with porous nano hollow shell (HSPI) was prepared for the first time by the hard template method by adjusting the addition ratio of the template precursor. SiO2 nanospheres not only serve as template agents but also as dispersants to make precursors of SPI more uniform, and the degree of polymerization will be better, resulting in significantly enhanced crystallinity of HSPI relative to bulk SPI (BSPI). More strikingly, it is found that HSPI has a larger specific surface area, stronger visible light absorption, and higher separation efficiency of photogenerated electron and hole pairs compared with BSPI by various spectral means characterization analysis. These favorable factors significantly enhanced the photocatalytic degradation of methyl orange (MO) by HSPI. This work provides a promising approach for the preparation of cheap, efficient, environmentally friendly, and sustainable photocatalysts

Construction of Direct Z−Scheme SnS2 Quantum Dots/Conjugated Polyimide with Superior Photocarrier Separation for Enhanced Photocatalytic Performances

In this study, a novel direct Z-scheme SnS2 quantum dots/sulfur-doped polyimide (SQDs/SPI) photocatalyst was firstly fabricated by an in situ crystallization growth of SnS2 quantum dots on sulfur-doped polyimide through a facile hydrothermal method. The photocatalytic hydrogen production activity of 5SQDs/SPI samples reached 3526 μmoL g−1 in the coexistence of triethanolamine and methanol used as hole sacrificial agents, which is about 13 times higher than that of SPI under the same conditions and 42 times higher than that of SPI only as a hole sacrificial agent. The improvement can be related to the direct Z-scheme charge transfer in the tight interface between SQDs and SPI, which promoted rapid separation and significantly prolonged the lifetime of photoexcited carriers. The Z-scheme charge transfer mechanism was proposed. This discovery comes up with a new strategy for the development of an efficient, environmentally friendly, and sustainable sulfide quantum dots/polymer non-noble metal photocatalyst

Experimental chronic hepatitis B infection of neonatal tree shrews (<it>Tupaia belangeri chinensis</it>): A model to study molecular causes for susceptibility and disease progression to chronic hepatitis in humans

<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) infection continues to be an escalating global health problem. Feasible and effective animal models for HBV infection are the prerequisite for developing novel therapies for this disease. The tree shrew (<it>Tupaia</it>) is a small animal species evolutionary closely related to humans, and thus is permissive to certain human viral pathogens. Whether tree shrews could be chronically infected with HBV in vivo has been controversial for decades. Most published research has been reported on adult tree shrews, and only small numbers of HBV infected newborn tree shrews had been observed over short time periods. We investigated susceptibility of newborn tree shrews to experimental HBV infection as well as viral clearance over a protracted time period.</p> <p>Results</p> <p>Forty-six newborn tree shrews were inoculated with the sera from HBV-infected patients or tree shrews. Serum and liver samples of the inoculated animals were periodically collected and analyzed using fluorescence quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, Southern blot, and immunohistochemistry. Six tree shrews were confirmed and four were suspected as chronically HBV-infected for more than 48 (up to 228) weeks after inoculation, including three that had been inoculated with serum from a confirmed HBV-infected tree shrew.</p> <p>Conclusions</p> <p>Outbred neonatal tree shrews can be long-term chronically infected with HBV at a frequency comparable to humans. The model resembles human disease where also a smaller proportion of infected individuals develop chronic HBV related disease. This model might enable genetic and immunologic investigations which would allow determination of underlying molecular causes favoring susceptibility for chronic HBV infection and disease establishment vs. viral clearance.</p