Characteristics of Solute Transport Continuously Released from Coastal Unconfined Aquifers under the Tidal Action Based on Laboratory Experiment

Most studies on solute transport in coastal aquifers affected by tides focus on the transport of instantaneous released solute,and there are few studies on continuously released solute affected by tides.In this study,the image monitoring method is used to establish the quantitative relationship between the concentration of the colored tracer and the hue value of the image,and the digital image is used to determine the tracer concentration distribution.Using image monitoring method laboratory experiments,quantitative analysis of the characteristics of continuously released solute transport in coastal unconfined aquifers under the tidal influence.Experiments show that the high tide inhibits the increase in the concentration of each point in the aquifer.Under the influence of tides,the solute plume retreats towards the land.During the low tide period,the solute plume migrates toward the sea again.And the solute plume will maintain a relatively stable shape after entering the aquifer for a long enough time.Ignoring the tidal effect seems to have little effect on the estimation of the position of the solute plume,but ignoring the tidal effect has a certain influence on the estimation of the dispersion range of the solute plume.No matter whether considering the tidal action,the final dispersion range of the solute plume is almost the same.But before the solute plume reaches a stable state,ignoring the tidal effect will lead to a smaller dispersion range of the solute plume.

Polycaprolactone/polyvinyl pyrrolidone nanofibers developed by solution blow spinning for encapsulation of chlorogenic acid

Study on the application of nanofibers in food active packaging has been a research hotspot in recent years.In this work,solution blow spinning(SBS)was applied to rapidly fabricate the polycaprolactone(PCL),polyvinyl pyrrolidone(PVP),and PCL/PVP nanofibrous films to encapsulate chlorogenic acid(CGA).All films showed uniform and smooth nanofibers,and the Fourier transform infrared spectroscopy and X-ray diffraction proved the success of mixed spinning of PCL and PVP.With the increase of PVP content,the thermal stability of the PCL/PVP nanofibrous films improved.The PCL/PVP(weight ratio of 4:1)film possessed better mechanical properties than PCL and PVP films be-cause of the stronger fiber-fiber interactions.The addition of PCL endowed the hydrophobic surfaces to the PCL/PVP films,and the PCL/PVP films had better water vapor barrier ability.The PCL/PVP(4:1)film exhibited the best long-term continuous release of CGA during 72 h.The PVP nanofibrous film exhibited no inhibition against Staphylococcus aureus and Escherichia coli due to the low encapsulation efficiency,but the PCL and PCL/PVP films exhibited good antimicrobial activity.The above results suggested that the nanofibrous fims developed by SBS possess promising prospects in food packaging.