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Accurately predicting the departure aircraft slip out time can effectively improve the airport surface operation efficiency and reduce the operation cost. A prediction model of departure and departure time based on BP neural network is established. The key factors influencing the actual slip out time are analyzed,and the correlation is tested. The model is verified by two weeks' actual operation data of an airport in central and southern China,and the root mean square error(RMSE),mean absolute error(MAE)and MAE percentage are analyzed. The results show that there is a strong correlation between the number of aircraft launched in the same period,the number of aircraft taking off in the same period,the number of aircraft in the same period,the average taxiing time within one hour and the taxiing time of departing aircraft. The taxiing distance,the number of turns and the delay time are related to the taxiing time,but not significant. The time period at which the aircraft takes off is not related to the slip out time. The average slip out time within 1 hour plays an important role in improving the prediction accuracy of the model. The introduction of relevant but insignificant influencing factors plays a certain role in improving the accuracy of prediction results. After the introduction of irrelevant factors,the prediction accuracy of the model will decrease significantly.

In order to solve the problem of demulsification of oil-water emulsion, a new type of highly efficient and recyclable magnetic fluorine-containing polyether composite demulsifier (Fe3O4@Ti-F) was synthesized. Fe3O4@Ti-F was prepared by one-pot method to combine magnetic nanomaterial TiO2 with Fe3O4 and graft fluorinated polyether. The successful synthesis of Fe3O4@Ti-F was confirmed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and X-ray diffraction (XPS). The demulsification performance of Fe3O4@Ti-F was evaluated by using the self-made crude oil emulsion as the experimental object. The demulsification mechanism of the demulsifier and the influence of external factors such as temperature and pH on the demulsification performance of the demulsifier were discussed, and the amount of TiO2 in the preparation process was determined. The results show that the demulsification efficiency of 50:50 (v/v %) W/O emulsion can reach 90.83% when the dosage of Fe3O4@Ti-F is 600 mg/L, the temperature is 65 °C and the time is 30 min. In the neutral acid environment, the demulsification rate of the demulsifier is above 80%. In addition, Fe3O4@Ti-F has been proved to have good magnetic effect. Under the action of external magnetic field, it can be recovered and recycled from the two-phase system for 4 times, and its demulsification efficiency is still above 60%. Fe3O4@Ti-F will have broad application prospects in the field of oil-water separation in an energy-saving way. [ABSTRACT FROM AUTHOR]

Aiming at the problem of delayed repair of cracks in the airtight wall of the goaf, a method to initiate crack repair using microcapsules in the initial stage of crack evolution of the airtight wall (cracking period) is proposed. This method makes use of the stress at the crack tip. The microcapsule wall is torn to allow the repair agent wrapped in the wall of the capsule to flow out and fill the gap. After the curing reaction, crack repair is completed. During the crack repair process of the airtight wall, the particle size of the microcapsule affects the strength of the capsule wall and directly affects the repair effect. In order to study the influence of particle size on the strength of microcapsules, eight kinds of microcapsules with different particle diameters and the same wall thickness were prepared by orthogonal experiments. The particle size and wall thickness were characterized by SEM, and the strength of the capsule wall was measured using nanoindentation technology. The quadratic function relationship that the strength of the capsule wall decreases with the increase of the particle size is obtained.

Oil in water (O/W) and water in oil (W/O) crude oil emulsions have caused many production safety hazards and environmental problems, which have attracted widespread attention. In this article, an amphiphilic nano demulsifier ZIF-8@CNTs was prepared by solvothermal method based on the metal-organic frameworks (MOFs) and carbon nanotubes (CNTs). Scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR) showed that ZIF-8@CNTs were grape dendritic, and ZIF-8 was successfully combined with OX-CNTs. Thermogravimetric analysis (TGA) showed that ZIF-8@CNTs had good thermal stability. The demulsification test showed that the demulsification rate could reach 99.4% when ZC-1 was added at 500 mg/L for 30 min at room temperature. The demulsification mechanism was studied by interfacial tension and interfacial activity experiments. [ABSTRACT FROM AUTHOR]

In this study, a new type of highly efficient and recyclable magnetic-fluorine-containing polyether composite demulsifier (Fe3O4@G-F) was synthesized by the solvothermal method to solve the demulsification problem of oil–water emulsion. Fe3O4@G-F was successfully prepared by grafting fluorinated polyether onto Fe3O4 and graphene-oxide composites. Fe3O4@G-F was characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Taking the self-made crude-oil emulsion as the experimental object, the demulsification mechanism of the demulsifier and the influence of external factors, such as the temperature and pH value, on the demulsification performance of the demulsifier are discussed. The results show that the demulsification efficiency of the Fe3O4@G-F emulsion can reach 91.38% within 30 min at a demulsifier dosage of 750 mg/L, pH of 6, and a demulsification temperature of 60 °C. In neutral and acidic environments, the demulsification rate of the demulsifier is more than 90%. In addition, Fe3O4@G-F has been proven to have good magnetic effects. Under the action of an external magnetic field, Fe3O4@G-F can be recycled and reused in a two-phase system four times, and the demulsification efficiency is higher than 70%. This magnetic nanoparticle demulsifier has broad application prospects for various industrial and environmental processes in an energy-saving manner. [ABSTRACT FROM AUTHOR]