Purification of carbazole by solvent crystallization under two forced cooling modes

To identify the effect of solvents and anthracene on the purification of carbazole,the solvent crystallization of carbazole was investigated with xylene,chlorobenzene and tetrachloroethylene(TCE)as solvents under two forced circulation cooling(FCC)modes.The co-crystalline experimental data were obtained from runs carried out at different anthracene levels between 1%(mass)and 10%(mass).The results showed that a uniform flake carbazole crystal obtained when using xylene and chlorobenzene under the FCC-1 mode with gradual cooling rate.Nevertheless,fine flake crystals grown under shock cooling of FCC-2 mode.It is beneficial to improving the purity of carbazole with chlorobenzene as solvent under cooling mode of FCC-1.Anthracene could promote the growth of carbazole in solution,and it has a significant influence on the purification of carbazole.

Compressive behavior of hybrid steel-polyvinyl alcohol fiber-reinforced concrete containing fly ash and slag powder:experiments and an artificial neural network model

Understanding the mechanical behavior of hybrid fiber-reinforced concrete(HFRC),a composite material,is crucial for the design of HFRC and HFRC structures.In this study,a series of compression experiments were performed on hybrid steelpolyvinyl alcohol(PVA)fiber-reinforced concrete containing fly ash and slag powder,with a focus on the fiber content/ratio effect on its compressive behavior;a new approach was built to model the compression behavior of HFRC by using an artificial neural network(ANN)method.The proposed ANN model incorporated two new developments:the prediction of the compressive stress-strain curve and consideration of 23 features of components of HFRC.To build a database for the ANN model,relevant published data were also collected.Three indices were used to train and evaluate the ANN model.To highlight the performance of the ANN model,it was compared with a traditional equation-based model.The results revealed that the relative errors of the predicted compressive strength and strain corresponding to compressive strength of the ANN model were close to 0,while the corresponding values from the equation-based model were higher.Therefore,the ANN model is better able to consider the effect of different components on the compressive behavior of HFRC in terms of compressive strength,the strain corresponding to compressive strength,and the compressive stress-strain curve.Such an ANN model could also be a good tool to predict the mechanical behavior of other composite materials.