Real time power management strategy for fuel cell hybrid electric bus based on Lyapunov stability theorem

The fuel cell/battery durability and hybrid system stability are major considerations for the power management of fuel cell hybrid electric bus (FCHEB) operating on complicated driving conditions. In this paper, a real time nonlinear adaptive control (NAC) with stability analyze is formulated for power management of FCHEB. Firstly, the mathematical model of hybrid power system is analyzed, which is established for control-oriented design. Furthermore, the NAC-based strategy with quadratic Lyapunov function is set up to guarantee the stability of closed-loop power system, and the power split between fuel cell and battery is controlled with the durability consideration. Finally, two real-time power management strategies, state machine control (SMC) and fuzzy logic control (FLC), are implemented to evaluate the performance of NAC-based strategy, and the simulation results suggest that the guaranteed stability of NAC-based strategy can efficiently prolong fuel cell/battery lifespan and provide better fuel consumption economy for FCHEB.     

基于误差估值累加开环校正的诱导式欺骗检测方法

诱导式卫星欺骗干扰可诱导航空器逐渐偏离预定航迹，难以被发现，因此及时有效地检测干扰是飞行安全的保障。在现有紧组合导航体制基础上，设计了一种基于误差估值累加开环校正的紧组合导航结构，并证明了其性能与传统闭环校正紧组合导航性能等效。在此结构中，将紧组合导航系统与自适应序贯概率比检测方法结合，提出了一种基于误差估值累加开环校正的诱导式欺骗检测方法，融合紧组合导航信息与其他不受欺骗影响的导航信息，构建欺骗检测统计量进行诱导式欺骗检测。仿真结果表明，开环校正结构可避免随时间累加的惯性导航系统误差所导致的组合导航滤波器发散问题，同时欺骗检测方法可进一步提高算法对“最坏”情形下微小诱导式欺骗的检测效果。     

Differential gene expression of the healthy conjunctiva during the day

PurposeTo determine if there is diurnal variation in gene expression in normal healthy conjunctival cells.MethodsBulbar conjunctival swab samples were collected from four healthy subjects in the morning and evening of the same day. The two swab samples were taken from one eye of each participant, with a minimum of five hours gap between the two samples. RNA was extracted and analysed using RNA sequencing (RNA-Seq).ResultsA total of 121 genes were differentially expressed between the morning and the evening conjunctival samples, of which 94 genes were upregulated in the morning, and 27 genes were upregulated in the evening. Many of the genes that were upregulated in the morning were involved in defence, cell turnover and regulation of gene expression, while the genes upregulated in the evening were involved in signalling and mucin production.ConclusionsThis study has identified several genes whose expression changes over the course of the day. Knowledge of diurnal variations of conjunctival gene expression provides an insight into the regulatory status of the healthy eye and provides a baseline for examining changes during ocular surface disease.     

New food safety challenges of viral contamination from a global perspective: Conventional,emerging, and novel methods of viral control

Food- and waterborne viruses, such as human norovirus, hepatitis A virus, hepatitis E virus, rotaviruses, astroviruses, adenoviruses, and enteroviruses, are major contributors to all foodborne illnesses. Their small size, structure, and ability to clump and attach to inanimate surfaces make viruses challenging to reduce or eliminate, especially in the presence of inorganic or organic soils. Besides traditional wet and dry methods of disinfection using chemicals and heat, emerging physical nonthermal decontamination techniques (irradiation, ultraviolet, pulsed light, high hydrostatic pressure, cold atmospheric plasma, and pulsed electric field), novel virucidal surfaces, and bioactive compounds are examined for their potential to inactivate viruses on the surfaces of foods or food contact surfaces (tools, equipment, hands, etc.). Every disinfection technique is discussed based on its efficiency against viruses, specific advantages and disadvantages, and limitations. Structure, genomic organization, and molecular biology of different virus strains are reviewed, as they are key in determining these techniques effectiveness in controlling all or specific foodborne viruses. Selecting suitable viral decontamination techniques requires that their antiviral mechanism of action and ability to reduce virus infectivity must be taken into consideration. Furthermore, details about critical treatments parameters essential to control foodborne viruses in a food production environment are discussed, as they are also determinative in defining best disinfection and hygiene practices preventing viral infection after consuming a food product.     

Surface energies in high-entropy carbides with variable carbon stoichiometry

The carbon vacancy in high-entropy carbides (HECs) has a significant impact on their physical and chemical properties, yet relevant studies have still been relatively few. In this study, we investigate the surface energies of HECs with variable carbon vacancies through first-principles calculations. The results show that the surface energy of the (1 0 0) surface of the stoichiometric HECs is significantly lower than that of (1 1 1) surface. With the decrease in carbon stoichiometry, the surface energies of both (1 0 0) and (1 1 1) surfaces increase gradually, which is mainly due to the weakening of covalent bonding and the decrease of metal Hirshfeld-I (HI) charges. However, the surface energy of (1 0 0) surface increases more quickly than that of (1 1 1) surface and will exceed that of (1 1 1) surface when the carbon stoichiometry decreases to a certain extent, which is primarily attributed to the greater decrease rate of metal HI charges of (1 0 0) surface.     

Multi-skeletal PtPdNi nanodendrites as efficient electrocatalyst with high activity and durability towards oxygen reduction reaction

Engineering alloy nanostructures with a combination of highly active noble metals (Pt and Pd) and less electronegative non-noble metal (Ni) is found to be crucial for improving surface reactivity by enriching with active Pt sites. Herein, a multi-skeletal PtPdNi nanodendrites (NDs) was successfully formed by a simple one-pot method with structure directing agent. The modification of Pt electronic structure and their interaction due to compressive strain were explored using benchmark characterization techniques, which showed that the PtPdNi NDs possess Pt-enriched surface, corroborating to more active catalyst sites for oxygen reduction reaction (ORR) in acidic medium. The PtPdNi NDs have a higher electrochemical surface area (63 m² g^?1) and an earlier onset potential (1.01 V) than PtPd NDs, PtNi NDs, and commercial Pt/C catalysts, indicating the outstanding ORR performance. The high mass and specific activities, as well as superior durability after accelerated degradation test (ADT), highlight the remarkable electrocatalytic performance of PtPdNi NDs over others. As a result, enhancing Pt utilization through the formation of PtPdNi NDs could be a reliable strategy to improve ORR electrocatalysis for polymer electrolyte membrane fuel cell (PEMFC) applications.     

Statistical optimization of operating parameters of microbial electrolysis cell treating dairy industry wastewater using quadratic model to enhance energy generation

The performance of Microbial electrolysis cell (MEC) is affected by several operating conditions. Therefore, in the present study, an optimization study was done to determine the working efficiency of MEC in terms of COD (chemical oxygen demand) removal, hydrogen and current generation. Optimization was carried out using a quadratic mathematical model of response surface methodology (RSM). Thirteen sets of experimental runs were performed to optimize the applied voltage and hydraulic retention time (HRT) of single chambered batch fed MEC operated with dairy industry wastewater. The operating conditions (i.e) an applied voltage of 0.8 V and HRT of 2 days that showed a maximum COD removal response was chosen for further studies. The MEC operated at optimized condition (HRT- 2 days and applied voltage- 0.8 V) showed a COD removal efficiency of 95 ± 2%, hydrogen generation of 32 ± 5 mL/L/d, Power density of 152 mW/cm² and current generation of 19 mA. The results of the study implied that RSM, with its high degree of accuracy can be a reliable tool for optimizing the process of wastewater treatment. Also, dairy industry wastewater can be considered to be a potential source to generate hydrogen and energy through MEC at short HRT.     

IRS辅助的SWIPT系统中基于能效优先的波束成形设计与优化

以智能反射面(intelligent reflecting surface,IRS)辅助的无线携能通信(simultaneous wireless information and power transfer,SWIPT)系统为背景,研究了该系统中基于能效优先的多天线发送端有源波束成形与IRS无源波束成形联合设计与优化方法。以最大化接收端的最小能效为优化目标,构造在发送端功率、接收端能量阈值、IRS相移等多约束下的非线性优化问题,用交替方向乘子法(alternating direction method of multipliers,ADMM)求解。采用Dinkelbach算法转化目标函数,通过奇异值分解(singular value decomposition,SVD)和半定松弛(semi-definite relaxation,SDR)得到发送端有源波束成形向量。采用SDR得到IRS相移矩阵与反射波束成形向量。结果表明,该系统显著降低了系统能量收集(energy harvesting,EH)接收端的能量阈值。当系统总电路功耗为?15 dBm时,所提方案的用户能效为300 KB/J。当IRS反射阵源数与发送天线数均为最大值时,系统可达最大能效。     

Scalloped nickel/iron vanadium oxide-coated vanadium dioxides based on chemical etching-induced reconstruction strategy for efficient oxygen evolution

Developing highly efficient and stable noble metal-free electrocatalysts with excellent catalytic surface for oxygen evolution reactions (OER) is an essential link for stimulating hydrogen generation from water electrolysis. Herein, the scalloped nickel/iron vanadium oxide coated vanadium dioxide (named as VO₂@NFVO) has been successfully decorated via a urea-induced chemical etching-reconstruction process in the alkaline solution containing Fe²⁺ and Ni²⁺. Corresponding experimental measurements clearly show that favorable chemical etching occurs with the formation of new phases (eg, Ni₃V₂O₈, FeVO₄), which make it expose a large number of active sites and regulate the electron density of the active center, thus thereby dramatically enhancing the electrocatalytic performance by promoting electron transfer and optimizing the adsorption energy of reaction intermediates. Under optimized condition, the obtained VO₂@NFVO delivers excellent activity merely with smaller overpotential of 290 mV at 10 mA cm^?2, outperforming benchmark RuO₂ catalyst in an alkaline solution. Moreover, its superior durability is verified by chronoamperometry testing. This simple etching-reconstruction strategy opens a new avenue for the preparation of vanadium-based electrocatalysts.     

Shaking table study on seismic behavior of MSE wall with inclined backfill soils reinforced by polymeric geostrips

In this study, the seismic behavior of a mechanically stabilized earth (MSE) wall with inclined backfill is investigated under sinusoidal acceleration excitations using a series of 1-g shaking table tests performed on the MSE model of 150 cm in height reinforced with polymeric geostrips. The effects of the stiffness of the reinforcement and slope angles of the backfill soil on the acceleration amplification factor (RMSA), the lateral displacement of the wall, the surface displacement of the backfill, the distribution of dynamic earth pressure along the height of reinforced wall and the strain distributions on the surfaces of the polymeric geostrips in three planes of the wall are investigated. The experimental results show that the dynamic earth pressure determined by traditional pseudo-static approaches leads to overestimated values. In addition, increasing the inclination angle of backfill soil results in the increase of surface settlement, lateral wall displacements, soil dynamic earth pressures, acceleration amplification factors and strains on the polymeric geostrip materials. The stiffness of the polymeric geostrip material has a negligible effect on the displacement, dynamic earth pressures and failure surface geometry.