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In order to investigate the effects of pore structure and hydrodynamic forces on particle transport and deposition, an experimental study on the transport and deposition of suspended particles (SP) in saturated porous media (quartz sand and glass beads) was conducted under five different flow velocities at room temperature (22–25 °C). Silt particles with a mode of 10.7 μm diameter and fluorescein (as the dissolved tracer (DT)) were injected into the columns in short pulses. The SP transfer parameters were compared to the DT one. All the parameters (dispersivity, recovery rate, and deposition rate) obtained from the breakthrough data varied with the flow rate. The breakthrough curves were well described by an analytical solution of the advective–dispersive equation with a first-order deposition kinetic. The results showed that the transport of the SP was faster than the DT when the flow velocity reached a critical value which was different between the glass beads and quartz sand. The mean diameter of the recovered particles and the longitudinal dispersivity increase with flow rate; In addition, the recovery rate of SP is higher in the glass beads than in the quartz sand even under similar porosities. This study highlights the significance of pore structure and hydrodynamic forces in transport and deposition processes of SP.

Sand column tests were conducted to investigate the seepage transport of silicon powders (SPs) with two wide particle size ranges (30-2000 nm and 2-70 μm), including the cotransport of SPs and copper ions. The results show that the graded large-scale SP has an obvious inhibiting influence on the transport of copper ions. In contrast, in the presence of the graded small-scale SP, the concentration of copper ions in the effluent tends to increase; i.e., there appears to be a promoting effect. However, after a long transport distance, the presence of SPs, regardless of particle size, has an overall retarding effect on heavy metal pollutants (e.g., copper ions). The promoting effect of the increase in seepage velocity on the concentration of copper ions in the effluent is greater with the graded large-scale SPs than with the graded small-scale SPs. In terms of the microstructural characteristics by metallographic microscopy, the average particle size of the deposited graded small-scale SPs is almost constant at different transport distances, while that of the deposited graded large-scale SPs tend to decrease significantly with increasing transport distance; i.e., notable bed filtration is exhibited in the latter case. This physical mechanism also determines the sequence and rate of the retarding effect of SPs on heavy metal ions under seepage flow.

Background: Poststroke insomnia (PSI) is a frequent complication of stroke usually as a comorbidity of poststroke depression and mainly occurs within the first 6 months after stroke. [ 1 ] Addressing PSI to improve stroke prognosis is of great value. Herbal medicine like Chaihu Longgu Muli Decoction (CLMD), which is commonly considered to be a good treatment for depression and epilepsy, has the therapeutic potential on PSI; however, insufficient systematic reviews were conducted to testify its efficacy. Therefore, the objective of this paper is to provide reliable evidence of the efficacy and safety of CLMD on PSI and a foundation for further investigation. Methods: The literature of clinical randomized controlled trials (RCTs) regarding CLMD for PSI published before June of 2021 will be retrieved in the databases, and 2 investigators will be asked to collect and crosscheck the data independently. For the including studies, the quality evaluation on methodology will be assessed in the light of the Cochrane Handbook for Systematic Review of Interventions V.5.1.0 as well as the quality of evidence will be evaluated by the Grading of Recommendations Assessment, Development, and Evaluation. Besides, the assessment of heterogeneity and reporting bias, the sensitivity analysis and the subgroup analysis will be conducted. Stata 15 will be applied to analyze the above data. Results: The review will conduct a high-quality synthesis on present evidence of CLMD for PSI. Conclusion: The conclusion of the study will indicate whether CLMD is effective and safe for PSI.