Biomedical implants have revolutionised medicine, while they also increase the risk of implant-associated infection which is one of the most frequent and severe complications accompanied by the ...application of biomaterials. Since the widespread usage of antibiotics drives the emergence of multidrug-resistant strains, the orthopaedic implant infections are usually hard to treat due to the antibiotic resistance, tolerance and/or persistence of pathogens. Given the growing impact of multidrug resistance, an urgent need has been triggered to develop new types of antimicrobial strategy other than using antibiotics. In this review, the authors highlight the recent progress on antimicrobial biomaterials with non-antibiotic strategies including chemical strategy, physical strategy, and synergetic strategy. The antimicrobial mechanisms of many kinds of non-antibiotic antimicrobial biomaterials are still not fully understood. Researchers gradually found that welcoming microbial cellular adhesion to a lethal surface was a more effective solution than targeting microbial cellular repulsion when designing antimicrobial surfaces. Moreover, there is a popular tendency to make the antimicrobial biomaterials not only kill pathogenic microbes but also facilitate the adhesion and growth of the healthy cell, which means that the next generation biomaterials should possess dual functions of preventing microbial infection together with promoting tissue regeneration simultaneously for biomedical applications.
A stable and efficient cooling and heat dissipation system of lithium battery pack is very important for electric vehicles. The temperature uniformity design of the battery packs has become ...essential. In this paper, an optimization design framework is proposed to minimize the maximum temperature difference (MTD) of automotive lithium battery pack. Firstly, the cooling channels of two cooling and heat dissipation structures are analyzed: serpentine cooling channel and U-shaped cooling channel. The results show that the serpentine cooling channel has better cooling effect. Secondly, the adaptive ensemble of surrogate models based on an improved particle swarm optimization algorithm is proposed to aid the optimization design of the serpentine cooling channel. The results show that the maximum temperature difference of the optimized scheme is reduced by 7.49% compared with the initial scheme, and the temperature field distribution of the lithium battery pack is more uniform. The proposed optimization design framework has certain guiding significance for the liquid cooling design of the battery packs.
Display omitted
•PBDE concentrations followed by OPEs were highest in soils from the area.•FR levels were higher in the e-waste dismantling park than in the surrounding area.•Direct emission was the ...main contributor, both in and outside the industrial park.•Increasing the distance from emission source reduced concentrations except for OPEs.•There were no obvious non-carcinogenic risks from oral ingestion and dermal contact.
Electronic waste (e-waste) dismantling is an important source of flame retardant emissions, and may have potentially adverse effects on surrounding area. This study investigated their influence on the surrounding area and the human health risks after an industrial park was built in 2015 and environmentally friendly technologies were introduced at an e-waste dismantling site in South China. The concentrations of flame retardants, including polybrominated diphenyl ethers (PBDEs), polybromobenzenes (PBBzs), Dechlorane plus (DP), and organophosphate esters (OPEs), in the soils were measured. The results showed that soil contamination was greater in the industrial park than in the surrounding area. The PBDE concentrations were the highest with BDE209, a daca-BDE, being the dominant congener, followed by OPEs, where triphenyl phosphate levels were the highest. Furthermore, triphenyl phosphate can be used as an indicator of flame retardant emissions during e-waste dismantling in this region. The fanti value of DP was stable at around 0.75. The principal component analysis showed that direct emission was the major source of pollutants in the industrial park. The direct emission proportion decreased in the surrounding area, but migration and transformation increased. None of the chemicals posed a non-carcinogenic risks to children and adults via oral uptake or dermal contact when the absorption factors of the chemicals were included in the estimation. However, the total hazard quotients for children were close to a unit in the industrial park, of which, the PBDE and OPE proportions accounted for 84.2% and 15.8% of the total, respectively. However, the PBBz and DP percentages were negligible. Therefore, PBDEs and OPEs should be given more attention in the future.
High‐energy Li‐rich layered cathode materials (≈900 Wh kg−1) suffer from severe capacity and voltage decay during cycling, which is associated with layered‐to‐spinel phase transition and oxygen redox ...reaction. Current efforts mainly focus on surface modification to suppress this unwanted structural transformation. However, the true challenge probably originates from the continuous oxygen release upon charging. Here, the usage of dielectric polarization in surface coating to suppress the oxygen evolution of Li‐rich material is reported, using Mg2TiO4 as a proof‐of‐concept material. The creation of a reverse electric field in surface layers effectively restrains the outward migration of bulk oxygen anions. Meanwhile, high oxygen‐affinity elements of Mg and Ti well stabilize the surface oxygen of Li‐rich material via enhancing the energy barrier for oxygen release reaction, verified by density functional theory simulation. Benefited from these, the modified Li‐rich electrode exhibits an impressive cyclability with a high capacity retention of ≈81% even after 700 cycles at 2 C (≈0.5 A g−1), far superior to ≈44% of the unmodified counterpart. In addition, Mg2TiO4 coating greatly mitigates the voltage decay of Li‐rich material with the degradation rate reduced by ≈65%. This work proposes new insights into manipulating surface chemistry of electrode materials to control oxygen activity for high‐energy‐density rechargeable batteries.
A dielectric inverse spinel‐structured Mg2TiO4 coating on Li‐rich cathode material significantly suppresses the continuous oxygen release, endowing batteries with remarkable cyclability and well‐inhibited voltage decay, e.g., showing a capacity retention of ≈81% and voltage degradation of only 151 mV after 700 cycles, far superior to 44% and 432 mV of the unmodified counterpart.
PDF
