A structurally related model for the calculation of the viscosity of silicate melts is proposed based on the general behavior of the viscosity of binary silicate melts. It relates viscosity to the degree of polymerization, as represented by the three types of oxygen in the melts. The model parameters for binary systems were optimized to give best fit to the experimental values. For ternary systems, it was assumed as a first approximation that the model parameters were linear functions of the parameters of the two binary silicate systems. The model has been applied to the CaO-SiO 2 , MgO-SiO 2 , and MnO-SiO 2 binary systems and the CaO-MgO-SiO 2 and CaO-MnO-SiO 2 ternary systems. Good agreement was obtained between calculated values and experimental data over the composition and temperature ranges in which experimental data exist. Comparison was made between the present model and the Urbain model. The present model has the capability of representing changes in viscosity due to substitution of cation species in silicate melts.

Black phosphorus quantum dots (BPQDs) have been prepared by a high turbulent shear rate generated from a household kitchen blender. A layer-by-layer disintegration mechanism of bulk BP crystals is suggested. As-synthesized BPQDs have shown excellent humidity sensing and photothermal converting properties. Importantly, this work not only explores potential applications for the BPQDs but also provides a successful paradigm for preparing the QDs of other layered materials.

The size and fractal dimension of asphaltene aggregates were investigated for two Western Canadian bitumens diluted with n-heptane at concentrations above the onset of precipitation. Asphaltene aggregate size distributions were measured over time using focused beam reflectance and micrographic methods in a series of batch experiments at different n-heptane contents and shear rates. The fractal dimensions of the aggregates were determined from the volume of the settled aggregates. The asphaltenes formed approximately log-normal size distributions with volume mean diameters of tens to hundreds of micrometers, depending mainly upon the n-heptane content. The distributions were established in less time than the first measurement could be obtained (about 30 s) and changed relatively little afterward. The average aggregate size increased with an increasing n-heptane content but reached a plateau value at 70–80 wt % n-heptane. The fractal dimension reached a maximum at a similar n-heptane content. Micrographic images and fractal dimensions indicated that, near the onset of precipitation, compact linear and planar aggregate structures dominated. At higher n-heptane contents up to approximately 75 wt % n-heptane, the aggregates remained compact but became more three-dimensional. At higher n-heptane contents, larger, looser structures were formed that could be broken under sufficient shear but did not reaggregate. The results were consistent with simultaneous nucleation, growth, and flocculation processes, where the precipitating material was initially sticky but lost its stickiness over time. The loss in stickiness was confirmed with surface force adhesion measurements.

The viscosity of iron-containing silicate slags in the CaO-MgO-MnO-FeO-Fe 2 O 3 -SiO 2 system has been reviewed by analyzing the available experimental data and the results of modeling studies. The model proposed by the present authors [1] for the calculation of viscosity of silicate melts has been found to provide a reasonably good description of the behavior of the viscosity of these melts with respect to both the change in silica content and the effect of different cations on viscosity. The results of the present model are compared with those of the Urbain model [2] and that proposed by Utigard and Warczok (the UW model). [3] The present model and the UW model gave a similar order of accuracy, while the results of the Urbain model tended to be higher than the experimental data for most systems examined. Although none of these models is capable of representing some peculiar behaviors, such as the peak observed around the fayalite composition in the FeO-SiO 2 binary system and the isoviscosity contours found in the MnO-FeO-SiO 2 system, they are considered to be very useful for representing the general behavior of viscosity in the systems studied.

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