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Abstract: A model of the process in a wet reactor for flue gas desulfurization by corona discharges is provided. Through deriving dependences of chain length Θ, desulfurization rate of the flue gas upon the parameters of injected energy density q, pH values of the liquid absorbents and mass transfer efficiency factor φ it is found that under the conditions of given energy injection of corona discharges the flue gas desulfurization rate can be remarkably increased when the pH value is appropriately adjusted and the inner surface of the wet plasma reactor is appropriately porous. It is realizable that the energy consumption can be reduced to lower than 2–4Wh/Nm3, which is acceptable for industrial application. [Copyright &y& Elsevier]

Abstract: An industry-scale semi-wet technological process for flue gas desulfurization by corona discharges is recommended. Its characteristics are: (1) it uses an ac/dc power supply to generate uniformly distributed streamer plasmas; (2) it uses a partitioned wet reactor system in which SO2 in the flue gas is absorbed with ammonia water in its thermal chemical reaction stage and the generated solution is repeatedly sprayed and transferred at an appropriate flow rate to the successive plasma reaction stage under the conditions of keeping liquid flow in balance. In the plasma stage, SO2 absorption by the liquid is enhanced by the electric wind and the sulfites in the solution experiences plasma oxidization; (3) drying up the end liquid to produce powder-typed byproduct and discharging the end gas after heat exchange with the hot gas at the inlet. Through a pilot test of 12,000Nm3/h capacity of flue gas with an initial SO2 concentration of about 500ppm, results of desulfurization rate >95%, energy consumption in the reactor 1.8Wh/Nm3, ammonia slip less than 5ppm and qualified fertilizer byproduct are obtained. [Copyright &y& Elsevier]

The MAC (medium access control) of CSMA (carrier sense multiple access) is widely used in distributed wireless networks with random node locations. In CSMA MAC, two nodes that are within the range of one another cannot transmit packets simultaneously. Modeling the concurrently transmitting nodes is crucial for the performance analysis of the CSMA networks. In this paper, we study the density of concurrently transmitting nodes and propose another modification of classical hard core point process to accurately estimate the density of concurrently transmitting nodes, in the absence and in the presence of fading conditions. The MMHCP model we propose outperforms the popular Matérn type II model and the existing modified hard core point (MHCP) process model by avoiding the underestimation and alleviating the overestimation issues, respectively. We conduct extensive numerical analysis and simulations to evaluate the accuracy of our MMHCP model. Furthermore, we study the impact of the density of initial Poisson Point Process (PPP) and fading factor on the mean probability of successful reception and on the transmission capacity of networks from numerical analysis and simulations. [ABSTRACT FROM AUTHOR]

Combinatorial auctions are employed into many applications such as spectrum auctions held by the Federal Communications Commission (FCC). A crucial problem in such auctions is the lack of secure and efficiency mechanism to protect the privacy of the bidding prices and to ensure data security. To solve the problem, we propose an approach to represent the price as a polynomial’s degree based on verifiable secret sharing. So, we can obtain the two polynomials’s degree maximum/sum by the degree of the two polynomial’s degree sum/product. In the protocol, the bidders’ information is hidden. The auctioneers can receive the shares without a secure channel, so our protocol is more applicable to more scenarios. The scheme can resist the collusion attack, passive attack and so on. Moreover, Compared to Kikuchi (IEICE Trans Fundam Electron Commun Comput Sci 85(3):676–683, 2002); Suzuki and Yokoo (Secure combinatorial auctions by dynamic programming with polynomial secret sharing, 2003), the proposed scheme has the authentication property without increasing the communications cost. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) has attracted wide attention as anode materials of lithium ion batteries, however, restacking of rGO sheets limits its capacity and rate performance. To address this issue, a sandwich-like composite of N-doped carbon (NDC) and rGO (rGO@NDC) was fabricated via a process of absorbing [EMIm]N(CN) 2 ionic liquid on the surface of graphene oxide (GO) nanosheets and subsequent heat-treating of the composite. The rGO@NDC composite exhibits a high specific capacity of 409.4 mAh g−1 with a Coulombic efficiency of 100% after 50 cycles at a charge-discharge rate of 0.5 C, and a specific capacity of 222.8 mAh g−1 with no capacity fade after 1200 cycles at charge-discharge rate of 10 C. Compositing the rGO with NDC particles can decrease the superficial oxygen-containing functional groups of the rGO, and therefore decrease side reactions during battery cycling. And embedding of NDC particles on the surface of rGO sheets avoids the restacking of rGO sheets and enlarges the interlayer space of the rGO to facilitate Li+ transport within the rGO@NDC. Finally, the NDC particles provide more accessible sites for Li+, and rGO sheets as conductivity networks improves electron transport. [ABSTRACT FROM AUTHOR]

Abstract: For ammonia flue gas desulfurization (FGD), the sulfite to sulfate oxidation is very critical for industrial applications. This paper reports a novel corona plasma-induced oxidation technique to convert concentrated ammonium sulfites to sulfates in an aqueous solution. The streamer corona plasmas are generated with a dc superimposed ac power source. Ammonium sulfite solution is sprayed in a reactor by using two-phase nozzles. When the sulfite concentration is around 1–3molL−1, the oxidation efficiency after one-cycle processing is in the range of 20–60%. Multiple-cycle treatments can be used to improve the oxidation efficiency. The energy consumption is around 20Whmol−1. Based on the present investigations, we anticipate that an industrial plasma-assisted ammonium FGD can be applied in industries. [Copyright &y& Elsevier]

Zinc ferrite (ZFO) is a promising anode material to replace the conventional graphite used in lithium ion batteries. However, the unstable structure and poor electrical conductivity of ZFO hinder its practical applications. In this work, carbon-coated ZFO nanospheres anchored on the reduced graphene oxide (C/ZFO/rGO) was synthesized by the solvothermal method and subsequent carbonization with an ionic liquid. In such a sandwich structure, ZFO nanospheres are double-protected by rGO and ionic liquid-derived carbon to maintain structural integrity and enhance electrical conductivity. It was found that the discharge/charge specific capacity of lithium ion batteries with C/ZFO/rGO is capable to maintain to be 963/952 mAh g−1 after 60 cycles at a current density of 0.3 A g−1. Its discharge/charge specific capacity can maintain to be 183.3/180.2 mAh g−1 even after 2000 cycles at a current density of 8 A g−1. The improved cycling performance and enhanced rate capability can be explained by the enhanced electrode kinetics and less degradation of structural integrity resulted from the double-protected sandwich structure. Image 1 • ZnFe 2 O 4 nanosphere protected by graphene and carbon coating are prepared. • Double-protected structure enhances the stability and conductivity of the materials. • C/ZnFe 2 O 4 /rGO exhibits excellent electrochemical properties. [ABSTRACT FROM AUTHOR]