With the increasing energy demands for electronic devices and electrical vehicles, anode materials for lithium ion batteries (LIBs) with high specific capacity, good cyclic and rate performances ...become one of the focal areas of research. Among the various anode materials, SnO2/graphene nanocomposites have drawn extensive attentions due to their high theoretical specific capacities, low charge potential vs. Li/Li+ and environmental benignity. In this review, the advances, including the synthetic methods and structural optimizations, of the SnO2/graphene nanocomposites as anode materials for LIBs have been reviewed in detail. By providing an in-depth discussion of SnO2/graphene nanocomposites, we aim to demonstrate that the electrochemical performances of SnO2/graphene nanocomposites could be significantly enhanced by rational modifications of morphology and crystal structures, chemical compositions and surface features. Though only focusing on SnO2/graphene-based composites, the concepts and strategies should be referential to other metal oxide/graphene composites.
•The advances of SnO2/graphene composites as anode materials for LIBs are reviewed.•Preparation methods and structural modifications of SnO2/graphene are presented.•Relationships of Li storage property, nanostructures and composition are discussed.•Opportunities for future work are identified.
The antimicrobial properties of Ag-based materials have been actively investigated recently. In such materials, control of the size of the Ag particles is critical to their bactericidal performance. ...A novel one-pot sol-gel scheme is described here. It incorporates room-temperature ionic liquids (RTILs) to synthesize Ag/TiO2 nanocomposite powders. The presence of RTILs is indispensable to the control of the size of the Ag particles. Highly dispersed, metallic Ag nanoclusters are formed on the TiO2 nanoparticle surface after calcination of the gel. The average cluster size of Ag can be controlled to be below 5 nm with high Ag loading (7.4 wt%). Antibacterial tests using 7.4 wt% Ag/TiO2 on 10(5) CFU/mL Escherichia coli (E. coli) strains incubated on Luria-Bertani (LB)/agar plates show that bacterial growth was inhibited by 98.8% at an Ag concentration of 1.2 microg/mL Complete inhibition was achieved at 2.4 microg(Ag)/mL. At this concentration, a 3.9 wt% Ag/TiO2 sample, with a smaller Ag cluster size (<3 nm), completely inhibited bacterial growth in a more populated E. coli community (approximately 3 x 10(6) CFU/mL). In fact, 1.6 microg/mL Ag suppressed bacterial growth by 99.9% with 3.9 wt% Ag/TiO2. Both the small Ag cluster size and the unique structure of TiO2 nanoparticles supporting highly dispersed Ag clusters are identified to be the sources of a superior bactericidal performance of the RTILs-derived Ag/TiO2.
This paper proposes a novel and computationally efficient estimation algorithm for lithium-ion battery state of health (SoH) under the hood of incremental capacity analysis. Concepts of regional ...capacity and regional voltage are introduced to develop an SoH model against experimental cycling data from four types of batteries. In the obtained models, SoH is a simple linear function of the regional capacity, and the R-square of linear fitting is up to 0.948 for all the considered batteries with properly selected regional voltage. The proposed method without using characteristic parameters directly from incremental capacity curves is insensitive to noise and filtering algorithms, and is effective for common current rates, where rates of up to 1C have been demonstrated. Then, a model-based SoH estimator is designed and shown to be capable of closely matching battery's aging data from NASA, with the error less than 2.5%. Furthermore, such a small scale of error is achieved in the absent of state of charge and impedance which are often used for SOH estimation in available methods.
•A new SoH estimation algorithm has been proposed for lithium-ion batteries.•Concepts of regional capacity and voltage are introduced based on ICA.•SoH models are developed as linear functions of the regional capacity.•Experimental results show that the estimation errors are less than 2.5%.
This paper reviews the development, design and applications of electrochemical technologies in water and wastewater treatment. Particular focus was given to electrodeposition, electrocoagulation ...(EC), electroflotation (EF) and electrooxidation. Over 300 related publications were reviewed with 221 cited or analyzed. Electrodeposition is effective in recover heavy metals from wastewater streams. It is considered as an established technology with possible further development in the improvement of space-time yield. EC has been in use for water production or wastewater treatment. It is finding more applications using either aluminum, iron or the hybrid Al/Fe electrodes. The separation of the flocculated sludge from the treated water can be accomplished by using EF. The EF technology is effective in removing colloidal particles, oil & grease, as well as organic pollutants. It is proven to perform better than either dissolved air flotation, sedimentation, impeller flotation (IF). The newly developed stable and active electrodes for oxygen evolution would definitely boost the adoption of this technology. Electrooxidation is finding its application in wastewater treatment in combination with other technologies. It is effective in degrading the refractory pollutants on the surface of a few electrodes. Titanium-based boron-doped diamond film electrodes (Ti/BDD) show high activity and give reasonable stability. Its industrial application calls for the production of Ti/BDD anode in large size at reasonable cost and durability.
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•Carbon nitride quantum dots (CNQDs) were decorated onto TiO2 nanotube arrays (NTAs).•The CNQDs/TiO2 NTAs exhibits much improved photoelectrochemical activity.•The heterojunction ...displays efficient removal efficiencies for RhB and phenol.•Pollutants degradation mechanism over CNQDs/TiO2 NTAs was clarified.
In this study, an efficient heterojunction was constructed by anchoring graphitic carbon nitride quantum dots onto TiO2 nanotube arrays through hydrothermal reaction strategy. The prepared graphitic carbon nitride quantum dots, which were prepared by solid-thermal reaction and sequential dialysis process, act as a sensitizer to enhance light absorption. Furthermore, it was demonstrated that the charge transfer and separation in the formed heterojunction were significantly improved compared with pristine TiO2. The prepared heterojunction was used as a photoanode, exhibiting much improved photoelectrochemical capability and excellent photo-stability under solar light illumination. The photoelectrocatalytic activities of prepared heterojunction were demonstrated by degradation of RhB and phenol in aqueous solution. The kinetic constants of RhB and phenol degradation using prepared photoelectrode are 2.4 times and 4.9 times higher than those of pristine TiO2, respectively. Moreover, hydroxyl radicals are demonstrated to be dominant active radicals during the pollutants degradation.
The influence of obstacles on hydrogen explosion is studied by numerical simulation and dimensional analysis. The numerical simulation is conducted based on the premixed model in a closed rectangular ...duct with rectangular obstacles, and ten variables that affect the flame propagation velocity are analyzed by dimensional analysis. Continuous acceleration of flame and collision annihilation of flame were successfully realized through triangular obstacles in simulation. The result shows that with the number of obstacles changes, the flame invariably converts to hemispherical flame, finger flame, tongue flame, quasi-plane flame, and mouth flame in turn. But the flame front is more twisted in two obstacles due to hydrodynamic instability and vortices. Through the comparative analysis of the flame and flow field in the duct during hydrogen explosion. It is found that the flame-obstacles-flow field coupling and its hydrodynamic phenomena determine the flame deformation and changes in propagation velocity. The result of the dimensional analysis shows that the drag coefficient can well depict the effects of the shape of the obstacles, and the dimensionless qualitative and quantitative model of flame propagation speed is given and verified.
•Through numerical simulation, the hydrogen explosion characteristics are observed in the duct with triangular obstacles.•The coupling mechanism of flame-obstacle-flow plays a key role in hydrogen flame deformation and nonlinear acceleration.•The drag coefficient can well depict the effects of the obstacles shape.•The mathematical model of flame propagation speed is established and its effectiveness is verified.
•A novel developed adsorbent material derived from waste printed circuit boards’ component.•The innovative adsorbent material can effectively remove cadmium ions from aqueous solutions.•The maximum ...capacity for cadmium ion removal is 2.1mmol/g.•Cadmium removal capacity is either equivalent or better than commercial resins.
Cadmium is a highly toxic heavy metal even at a trace level. In this study, a novel material derived from waste PCBs has been applied as an adsorbent to remove cadmium ions from aqueous solutions. The effects of various factors including contact time, initial cadmium ion concentration, pH and adsorbent dosage have been evaluated. The maximum uptake capacity of the newly derived material for cadmium ions has reached 2.1mmol/g at an initial pH 4. This value shows that this material can effectively remove cadmium ions from effluent. The equilibrium isotherm has been analyzed using several isotherm equations and is best described by the Redlich–Peterson model. Furthermore, different commercial adsorbent resins have been studied for comparison purposes. The results further confirm that this activated material is highly competitive with its commercial counterparts.
A portfolio selection model with return as triangular intuitionistic fuzzy number is developed in this study to assess and select portfolios on China Stock Exchange. Although the portfolio selection ...has been widely investigated, and most studies have regarded return and risk as the main decisive criteria, there are many uncertainties in the financial market, such as social, political and human psychological factors, which makes it difficult for us to describe the risks in line with empirical evidence. To fill this gap, first, a literature review was conducted to clarify the current situation and shortcomings of portfolio selection. Second, the triangular intuitionistic fuzzy number was used to fuzzify the coefficients of the objective function and the constraints in the portfolio model. Third, the triangular intuitionistic fuzzy number model was transformed into a linear programming model by using the selected exact ranking function, and the model was solved by MATLAB. Finally, the historical monthly returns of 10 stocks in China’s Stock Exchange from December 2017 to November 2020, lasting 36 months, were selected to demonstrate the model. The results indicate that the portfolio selection model with triangular intuitionistic fuzzy number can better meet the uncertainty of the real securities market, and more reasonable investment decision guidance can be provided for investors. Besides, the limitations of this study are pointed out, and implications and directions for future research are discussed.
•Probability prediction method of a domino effect induced by lightning is proposed.•The most dangerous primary equipment situates at the dominant upwind direction.•The most susceptible target ...equipment is usually located between two tank groups.•The results are helpful for the prevention of domino effects induced by lightning.
A lightning strike is the main cause of fire accidents in chemical storage tanks, and the thermal radiation produced by a large storage tank fire may lead to a domino effect. A prediction method aiming to evaluate the probability of a domino effect at different levels triggered by lightning in the chemical tank farm is proposed. The developed method takes into account both the probability calculation model of fire triggered by lightning and the assessment method of the subsequent domino effect probability. Firstly, the accident scenarios and causes of fire triggered by lightning are analyzed by the event tree method, and a probability calculation model of fire accident triggered by lightning is developed. Secondly, the graph of chains of accidents is built considering synergistic effects and multi-level domino effects, and the Bayesian network is applied to calculate the probability of each accident chain. The most dangerous primary equipment is identified by comparison with the probabilities of the domino effect at different levels. By setting up the failure states of different tanks, the probabilities of events are updated under a given situation, and the most susceptible target equipment with respect to the domino effect are identified. Finally, the method is illustrated with two case studies in a chemical industry park. The results will be helpful for the prevention of domino effects based on the theory of chain-cutting disaster mitigation.
