Particuology最新文献

Fire smoke, which consists large amounts of fine particles, is considered as the fatal factor in fires. In this study, a fast smoke particle elimination method based on electro-acoustic coupling agglomeration technology is proposed. First, the experimental results show that the electro-acoustic coupling agglomeration has higher smoke elimination efficiency compared to single-field. The smoke transmission is much less than 80% after 30 s of single acoustic or electric field action, while the coupled field reaches 90%. Then, the effects of acoustic frequency, sound pressure level and voltage on the smoke elimination characteristics are discussed. It is found that the optimal acoustic frequency is 1.5 kHz. While as the sound pressure level and voltage increase, the elimination efficiency first increases and then tends to stabilize, the critical values of the sound pressure level and voltage are 135 dB and 7 kV. This indicates that there is an optimal combination of the three variables. Finally, through the theoretical analysis of particle movement and the micro-morphology of agglomerates, the particle agglomeration mechanism under the electro-acoustic coupling is analyzed. This study provides a new idea for the fast elimination of fire smoke particle.

Dynamic response of the screen mesh is of great significance in the optimum vibrating screen design. In this paper, based on the DEM-FEM co-simulation method, the effect of screening parameters on the dynamic response of the screen mesh is explored and the mechanism is revealed on the particle level. Firstly, a virtual experiment on a linear vibrating screen was carried out to analyze the screening parameters’ effect with both impact load and sustained stress inflicted on the screen mesh. Then, the time-domain evolution regularity of the screen mesh LVA (Local Vibration Amplitude) under different particle plugging conditions was investigated based on the co-simulation. Finally, the influence of screening parameters on LVA and its distribution was discussed. The results show that the screening parameters can greatly affect the screen mesh LVA and its distribution by changing the movement of the granular material and the particle penetration probability, which provides an important basis for the optimal design of the screen mesh and its supporting structure.

In recent years, significant progress has been achieved in the creation of innovative functional materials for energy storage and conversion. Due to their distinct physicochemical characteristics, ultrathin nanosheets composed of common layered transition metal sulfide materials (MoS₂) have demonstrated promise as high-capacity anode materials for lithium-ion batteries (LIBs). Nevertheless, their practical application is severely limited by the tendency of monolayer nanosheets to restack due to strong van der Waals forces, dramatic volume changes during successive cycles, and low intrinsic conductivity. Recent research advances have shown that composite structures and nanowire morphologies with specific morphologies effectively overcome these issues. This paper reviews the recent research progress on molybdenum disulfide-based composites as anode materials for LIBs and discusses in detail the structural characteristics of pure molybdenum disulfide and other composite forms of molybdenum disulfide. In addition, the phase engineering, defect engineering, and lithium storage mechanisms of molybdenum disulfide and the synthesis of molybdenum disulfide-based nanocomposites by different preparation methods are focused on. Finally, we review the design (structure), recent developments, and challenges of novel anode materials and consider their electrochemical performance in Li-ion batteries.

The nucleation and growth kinetics of benzoic acid were determined in a population balance model, describing the seeded batch antisolvent crystallization process. The process analytical technologies (PATs) were utilized to record the evolution of chord length distributions (CLDs) in solid phase together with the concentration decay in liquid phase, which provided essential experimental information for parameter estimation. The model was solved using standard method of moments based on the moments calculated from CLDs and solute concentration. A developed model, incorporating the nucleation and crystal growth as functions of both supersaturation and solvent composition, has been constructed by fitting the zeroth moment of particles and concentration trends. The determined kinetic parameters were consequently validated against a new experiment with a different flow rate, indicating that the developed model predicted crystallization process reasonably well. This work illustrates the strategy in construct a population balance model for further simulation, model-based optimization and control studies of benzoic acid in antisolvent crystallization.

Electrostatic precipitation is a process widely used as gas cleaning device, to removal particles from gas flows. However, in a conventional and well-sized precipitator, the collection efficiency decreases for ultrafine particles, making it difficult to employ this equipment for controlling nanoparticle pollution. This paper investigates the influence of plate spacing (4 and 6.5 cm) and wire spacing (4, 6, and 12 cm) on the electric current and nanoparticle collection efficiency, considering the effect of diffusion charging and electrostatic shielding. Two laboratory-scale dry wire-plate electrostatic precipitators with different plate spacings were tested for the collection of nanoparticles (6.15–241.4 nm) at three air velocities (1.9, 2.9, and 3.9 cm/s). The results demonstrated the effectiveness of the equipment in removing nanoparticles (99.9%) under the highest electric fields. Higher values of the wire spacing led to increases in the current and the collection efficiency. This was associated with reduced electrostatic shielding, which is more evident in smaller ducts with a higher density of field lines. It is expected that the findings should improve knowledge on electrostatic precipitation of nanoparticles, enabling optimization of collection efficiency by considering the effects of geometric parameters.

The mechanisms of new particle formation (NPF) events that occurred under high aerosol loadings (“polluted” NPF) in the atmosphere have been unclear, which has inhibited the precision of particle pollution control. To deepen the understanding of how the “polluted” NPF events occur, a one-month comprehensive measurement was conducted in the atmosphere of Beijing during the summer of 2016. The “clean” NPF events (frequency = 22%) (condensation sink, CS < 0.015 s⁻¹) were found to be caused by local nucleation and growth. The “polluted” NPF events (frequency = 28%) (CS > 0.015 s⁻¹) were influenced by both local nucleation-growth and regional transport, and the contributions from the two factors to 6–25 nm particle number concentration were 60% and 40%, respectively. This study emphasized the importance of the transport for nanoparticles in relatively polluted atmospheres, and for that the regional joint particle pollution control would be an essential policy.