Long non-coding RNAs (lncRNAs) regulate gene expression and are crucial for plant growth and development. However, the mechanisms underlying the effects of activated lncRNAs on axillary bud development remain largely unknown. By lncRNA transcriptomes of axillary buds in topped and untopped tobacco plants, we identified a total of 13,694 lncRNAs. LncRNA analysis indicated that the promoted growth of axillary bud by topping might be partially ascribed to the genes related to hormone signal transduction and glycometabolism, trans-regulated by differentially expressed lncRNAs, such as MSTRG.52498.1, MSTRG.60026.1, MSTRG.17770.1, and MSTRG.32431.1. Metabolite profiling indicated that auxin, abscisic acid and gibberellin were decreased in axillary buds of topped tobacco lines, while cytokinin was increased, consistent with the expression levels of related lncRNAs. MSTRG.52498.1, MSTRG.60026.1, MSTRG.17770.1, and MSTRG.32431.1 were shown to be influenced by hormones and sucrose treatments, and were associated with changes of axillary bud growth in the overexpression of NtCCD8 plants (with reduced axillary buds) and RNA interference of NtTB1 plants (with increased axillary buds). Moreover, MSTRG.28151.1 was identified as the antisense lncRNA of NtTB1. Silencing of MSTRG.28151.1 in tobacco significantly attenuated the expression of NtTB1 and resulted in larger axillary buds, suggesting the vital function of MSTRG.28151.1 axillary bud developmen by NtTB1. Our findings shed light on lncRNA-mRNA interactions and their functional roles in axillary bud growth, which would improve our understanding of lncRNAs as important regulators of axillary bud development and plant architecture.

Solid waste sorting is an important pre-treatment in recycling to improve the efficiency of material recovery and reduce costs. Motivated by the PEACOC project on metal recovery from solid wastes, an innovative magnetic density separation (MDS) process has been developed for solid waste sorting. It has intrinsic advantages over conventional gravity separation technologies and the previously industrialized MDS process. The new MDS process applies an inclined planar magnet and a horizontal basin containing a static magnetic fluid as the separation medium. A particle sliding phenomenon is identified as a feature that could help the separation. Experiments have been carried out to demonstrate the role of the MDS in concentrating valuable metals in shredded PCBAs and reducing metallic contaminants in plastic fractions of shredded wires. A pilot scale facility is introduced to show the design to achieve continuous production and to reduce the consumption of ferrofluid.

Ionic rare earth ore is a type of featured rare earth ore in China. Its mining process suffers from a long leaching cycle and considerable consumption of leaching agents. Improving mining efficiency requires a sound physical understanding of the leaching process. In this study, the CFD‐based numerical model is used to analyze the physical process of leaching through porous media formed by particles. The simulation results indicate that a lower packing porosity and smaller particles packed granular porous medium result in much larger energy dissipation during seepage, and the energy dissipation increases with seepage velocity. It is found that when the seepage velocity increases to a certain high value, the energy dissipation exceeds the value predicted by Darcy’s law, which is mainly caused by liquid turbulence. Additionally, the effect of particle shape is examined. The results show that the granular medium composed of prolate particles causes larger energy dissipation than oblate particles, and spherical particles play the least role. This phenomenon may result from the particle shape affecting the area of the frontal contact surface between particles and liquid. The results provide new insights into the fundamental understanding of percolation and seepage behaviors in the ion‐adsorption‐type rare earth ore leaching process.

Motivated by the PEACOC project on metal recovery from solid wastes, an innovative magnetic density separation (MDS) process has been developed for granular material sorting. It has intrinsic advantages over the existing industrialized MDS by eliminating fluid turbulence and particle jamming problems. The new MDS applies an inclined planar magnet and a horizontal basin containing a static magnetic fluid as the separation medium. A particle sliding phenomenon is identified as a feature of the process which could help the separation. The MDS successfully sorted shredded PCBAs to concentrate valuable metals and sorted shredded wires to reduce metallic contaminants in the plastic fractions. A pilot scale facility is introduced to show the design to achieve continuous production and to reduce the consumption of ferrofluid.

Nanomaterial provides a new method for underground water leakage control whereby nanoparticle suspensions are slowly injected and transported through the groundwater flow into the target position. This is a new method different from traditional cement grouting. The material properties of the nanomaterial grout strongly influence the effectiveness of grouting process by the nanoparticles. This paper conducted viscosity tests and Cryo-scanning electron microscope (Cryo-SEM) to investigate the viscosity growth rule and microstructure of nanomaterial grout for soil treatment. Laponite was selected as the representative nano layered silicate. Possible solution concentrations and gel time are analysed precisely. The moderate concentrations (2.5-3.5%) with gel time (5-7 days) are more appropriate for laponite grout. In addition, the direct micrograph of laponite grout with different concentrations was also achieved. The results can establish viscosity and microscopic structure characterization description of laponite grout, and will benefit the practical implementation of this method of water leakage control.