Theoretical Investigation of Thermodynamic Properties of the Al-Si-Fe Ternary Alloy.

Aiming at the current lack of thermodynamic parameters related to the preparation of aluminum-silicon-iron alloys from spent refractory materials in aluminum electrolytic cells, the Miedema model was used to calculate the thermodynamic parameters of Al-Si, Al-Fe, and Si-Fe binary alloys. On this basis, the Toop model was combined to calculate the mixing enthalpy ΔH, excess entropy SE, excess Gibbs free energy GE, and component activity α of Al-Si-Fe ternary alloys. The results show that ΔH, SE, and GE of binary alloys are all negative values. The properties of the Al element and Si element are similar, and they are different from the Fe element. The ternary alloys also have negative values of ΔH, SE, and GE in the alloy composition range, and their values change obviously in the region where the content of Fe is high or low. The activity values of all components decrease dramatically along with the diminishing of the corresponding molar fractions, and the activity values of Al, Si, and Fe are smaller in the central portion of the triangle of ternary components. It indicates that there is a strong interaction between the three elements, which easily forms ternary intermetallic compounds.

Non-Destructive Determination of Bayberry Sugar and Acidity by Hyperspectral Remote Sensing of Si-Sensor and Low-Cost Portable Instrument Development.

The digitalization of information is crucial for the upgrading of the bayberry digital agriculture industry, while the low-cost information detection sensing equipment for bayberry are a bottleneck for the digital development of the industry. The existing rapid and non-destructive detection devices for fruit acidity and sugar content mainly use near-infrared and mid-infrared spectral characteristic for detection. These devices use expensive InGaAs sensor, which are difficult to promote and apply in the bayberry digital industry. This study is based on the high-spectral range of 454-998 nm in bayberry fruit to study the mechanism of fruit sugar and acidity content detection and to develop a portable bayberry fruit sugar and acidity detection device using Si-sensor in order to achieve low-cost quality parameter detection of bayberry fruit. The research results show that: Based on the hyperspectral of bayberry fruit, the sensitive wavelength for sugar content inversion is 610 nm, and the inversion accuracy (RMSE) is 1.399Brix; the sensitive wavelength for pH inversion is 570 nm, and the inversion accuracy (RMSE) is 0.1329. Based on the above spectroscopic detection mechanism and spectral dimension reduction methods, combined with low-cost Si-sensor (400-1000 nm), a low-cost non-destructive portable bayberry fruit sugar and acidity detection device has been developed, with detection accuracies of 94.74% and 97.14%, respectively. This bayberry fruit sugar and acidity detector provides a low-cost portable non-destructive quality detection instrument of bayberry, which is in line with the industrial group of low consumption in which the bayberry is mainly cultivated on a small scale, accelerating the digitalization process of the bayberry industry.

First-Principles Molecular Dynamics Simulation on High Silica Content Na3AlF6-Al2O3-SiO2 Molten Salt.

A new method for the disposal of the spent refractory materials by adding them directly to electrolytic cells requires our better knowledge of the Na3AlF6-Al2O3-SiO2 melt system. The development of computational materials science offers us a new way to avoid the limitation of the experiment under a strong corrosive environment at high temperatures. First-principles simulation is applied to study the structure information, electronic properties, and transport properties of the system. The study reveals that the main Si and Al ions in the melt are complex ion groups such as [SiF2O2]2-, [SiFO3]3-, [SiF3O2]3-, [AlF2O2]3-, [AlF3O]2-, and [AlF4O]3-. Tangled structures like [SiAlO3F5]4- also exist in the melt. The average coordination number of Al-F and Si-F is 3.21 and 2.45, respectively. O ions mainly act as bridge ions in the melt. The bonding ability of Al with O ions is stronger than that of Si with O ions. Moreover, the Al-O bond is mainly covalent, while the Al-F bond is basically ionic characters. The order of diffusion ability of ions from large to small is Na, F, Al, Si, and O. Addition of SiO2 into the Na3AlF6-Al2O3 molten salt causes an increase of the viscosity and a decrease of ionic conductivity.