Landfills receive about 350 million tons of municipal solid wastes (MSWs) per year globally, including antibiotics and other coselecting agents that impact antimicrobial resistance (AMR). However, little is known about AMR in landfills, especially as a function of landfill ages. Here we quantified antibiotics, heavy metals, and AMR genes (ARGs) in refuse and leachates from landfills of different age (<3, 10, and >20 years). Antibiotics levels were consistently lower in refuse and leachates from older landfills, whereas ARG levels in leachates significantly increased with landfill age (One-way ANOVA, F = 10.8, P < 0.01). Heavy metals whose contents increased as landfills age (one-way ANOVA, F = 12.3, P < 0.01) were significantly correlated with elevated levels of ARGs (Mantel test, R = 0.66, P < 0.01) in leachates, which implies greater AMR exposure risks around older landfills. To further explain ARGs distributional mechanisms with age, microbial communities, mobile genetic elements (MGEs) and environmental factors were contrasted between refuse and leachate samples. Microbial communities in the refuse were closely correlated with ARG contents (Procrustes test; M = 0.37, R = 0.86, P < 0.001), whereas ARG in leachates were more associated with MGEs.

A new method for drilling holes in engineering ceramics by using a rotary ultrasonic tool has been developed. In this method, a drilling tool impregnated with abrasive particles is simultaneously rotated and vibrated. The mechanism of ultrasonic drilling is analysed using the concept of fracture mechanics and a new theoretical model of material removal rate (MRR) is proposed. According to this model, the material removal rate increases with increases of applied static load, amplitude of vibration and rotation speed of the drilling tool. Test results show that ultrasonic drilling is an eective method for machining engineering ceramics.

The fragmentation of elongated α grains accelerated by the growth of β phase in Ti-5Al-2Sn-2Zr-4Mo-4Cr during hot deformation was examined using electron backscattered diffraction (EBSD) and transmission electron microscopy (TEM). It was determined that boundary splitting resulted in the fragmentation of αE. The kinked sharp α grains, which were formed with help of "civilian" growth of β phase, are necessary structures for the fragmentation of elongated α grains. In addition, the texture results showed an initial deviation from Burgers orientation relationship (OR) in α/β interphase boundaries, indicating that the "civilian" growth of the β phase based on the pre-existing β grain boundaries implied a constant loss of coherency in α/β interphase boundaries, which also accelerated the fragmentation of elongated α grains.

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