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The key to shale gas exploration is the characterization of gas migration under the combination of multiple factors. To address the long-standing energy challenge of rapidly and accurately quantifying the behavior of natural fractures and matrix pores in shale at an engineering scale in interaction with gas migration. This study proposes an interdisciplinary model for shale gas extraction by adopting fractal theory. Five innovative microstructural parameters are developed to characterize the size and scale of natural matrix pores/fractures in shale, so as to investigate the contributions of fractal distributed pores and fractal power-law distributed fractures to shale gas extraction. The present results of the proposed model are consistent with the exploitation state of the UK Bowland Shale #114 well. The evolution of the shale microstructure will lead to changes in gas migration behavior throughout the reservoir and in turn affect shale stress, temperature and gas adsorption–desorption effect, and finally have a significant impact on permeability. It is found that in the present analysis of the entire Bowland Shale, the overall permeability changes by 10.8% with the evolution of fractal distributed pores and by 41.3% with the evolution of fractal power-law fractures. This work provides a new approach for rapidly exploring the behavior of shale fractures and matrix pores at engineering scales. This work also offers a new and practical baseline for shale gas extraction assessment and fossil energy management. [ABSTRACT FROM AUTHOR]

As the most significant nonlinear reservoir, the rocks have complex structural characteristic. The pore structure of the rock is varied in shape and complex in connectivity. However, the prevailing methods for characterising the microstructure of rocks, such as the coordination number method and fractal theory, are still difficult to quantify the structural properties. In this study, based on the CT-scan method and a new complex network theory, the topological characteristics of rocks such as seepage path selection, degree of pore aggregation, pore importance, and pore module structure are analysed. The results show that the scale-free network model is more reliable in characterising the rock pore network than previously published structural models, and a small number of pores are the "key" to the seepage process. Besides, we proposed a new method to quantify the importance of rock pores and present the distribution characteristics and connectivity laws of the rock-pore network. This provides a new method to study the seepage process of the nonlinear reservoirs. [ABSTRACT FROM AUTHOR]

Direct measurement of critical cooling rates has been challenging and only determined for a minute fraction of the reported metallic glass forming alloys. Here, we report a method that directly measures critical cooling rate of thin film metallic glass forming alloys in a combinatorial fashion. Based on a universal heating architecture using indirect laser heating and a microstructure analysis this method offers itself as a rapid screening technique to quantify glass forming ability. We use this method to identify glass forming alloys and study the composition effect on the critical cooling rate in the Al–Ni–Ge system where we identified Al51Ge35Ni14 as the best glass forming composition with a critical cooling rate of 104 K/s. [ABSTRACT FROM AUTHOR]

Rock contains a large number of micro-pores, which are of different shapes and complex structures. The structure information of sandstones is extracted based on different porosities through X-ray CT (Computer Tomography) scanning, photo processing techniques and complex network method to explore the topological structure of sandstone seepage network. The results show that sandstone seepage network has scale-free property. The minute quantities of pores with more throat connections have vital functions of overall connectivity of sandstone seepage network, while sandstone seepage network has strong robustness with random error. This research can provide reference for across scales research of porous seepage and multi-disciplinary application of complex network theory. [ABSTRACT FROM AUTHOR]

Abstract Although the impact of matrix microstructures on the evolution of coal permeability is significant, this impact has not been included in the analysis of coupled multiple processes during the extraction of coal seam gas. Previous studies normally investigate the relation between microstructures and coal porosity or permeability through imaging characterization techniques. In this study, we developed a fractal permeability model that defines coal permeability as a function of effective stress. In this model, coal microstructure is characterized by three fractal parameters: (1) fractal dimension of pore size; (2) fractal dimension of throat tortuosity; and (3) maximum pore size. These fractal dimensions may evolve with the effective stress through porosity. We applied this fractal permeability model to fully couple coal deformation and gas flow. Model results illustrate the significant differences between the fractal approach and the classical cubic model between permeability and porosity. When the porosity remains unchanged, the permeability calculated by the classical cubic model remains as a constant. However, the fractal permeability changes due to different microstructural parameters. These results show that the macroscopic permeability of coal is directly proportional to the fractal dimension and the maximum pore size, and is inversely proportional to the fractal dimension of the throat tortuosity. These characteristics cannot be captured by the classical cubic porosity-permeability model. [ABSTRACT FROM AUTHOR]

Frost heave is a major cause of engineering geology hazards in cold regions, which is mainly the result of frost-heaving pressure due to the non-linear transport-freezing of water in the pore network. However, few studies have fully quantified the contribution of the strata pore-network structure to that pressure and the hazard to cold-region projects under multifactorial effects. Therefore, to address this long-term challenge in cold regions, we pioneered a generic, interdisciplinary, thermal-hydrological-mechanical fractal model for the quantitative study of the effect of strata microstructure on frost heave and hence the assessment of construction risk for engineering geology projects. First, a strata frost heave model based on fractal theory is proposed, with pore fractal dimension, maximum pore diameter, and pore tortuosity fractal dimension used to characterize strata pore density, pore size, and throat complexity, respectively. Secondly, the numerical model is compared with field observations in cold-region projects, and reasonable agreements can be obtained. The results indicate that various fractal parameters have different effects on engineering geology projects in cold regions. The strata displacement changes by 9.7–20.3% as microscopic parameters change. This study contributes to a better understanding of the micro- and macro-interactions of soil in cold regions, as well as a reference for geoengineering stability in cold regions under frost heave conditions. • A general method is purposed for microstructure analysis during frost heave. • Fractal parameters enable rapid analysis for engineering micro-macro interactions. • The strata displacement changes by 9.7–20.3% under the evolution of microscopic parameters. • D p and d max are proportional to the frost depth and strata deformation. • More complex pore throat (D T) will mitigate the frost depth and strata deformation. [ABSTRACT FROM AUTHOR]

[Display omitted] • EGCG and quercetin were successfully encapsulated in double emulsion hydrogel beads. • EEs of EGCG and quercetin in hydrogel beads improved upon those of double emulsions. • Sodium alginate and Ca2+ formed a 3D network wherein the double emulsion adsorbed. • Hydrogel beads inhibited oil digestion without decreasing quercetin bioavailability. • Hydrogel beads increased the bioavailability of EGCG. Co-loaded (–)-epigallocatechin-3-gallate (EGCG) and quercetin double emulsions and hydrogel beads were prepared, and their structure, functions, and digestion characteristics were investigated. The double emulsion particles were adsorbed by the cross-linked chains of the hydrogel beads. The encapsulation efficiencies of EGCG and quercetin within the hydrogel beads were higher than those within the double emulsion, while the antioxidant activities of the double emulsions were higher than those of the hydrogel beads. A lower amount of free fatty acids (FFAs) was released from the hydrogel beads than that released from the double emulsions. The bioavailability of EGCG was higher in the hydrogel beads than those in the double emulsions, while the quercetin bioavailability was not significantly different expect for the ratio of 3:7. The hydrogel beads remained intact in the stomach; however, numerous oil spills occurred in the small intestine. These data may improve double-emulsion-based delivery systems for controlled lipolysis and the release of co-encapsulated hydrophilic and lipophilic bioactive compounds. [ABSTRACT FROM AUTHOR]

• Various interfacial structures were observed in the emulsions. • The SPs–TS mixtures displayed synergistic effects in interfacial tension decays. • TS as the outer layer improved the oxidative stability of the emulsion. • TS not only fills the interfacial gaps but also adsorbs on the particle surfaces. • TS inhibited the release of free fatty acids during emulsion digestion. Herein, the effects of the concentration (0.1%–1.0%, w/v) and addition sequence of tea saponin (TS) on the physical stability, oxidative stability, rheological properties, and in vitro digestion of the emulsions stabilized by heat-induced soy protein isolate nanoparticles (SPs) were investigated. The results revealed that the concentration and addition sequence of TS have significant impact on the microstructure, stability, rheological properties, and in vitro digestion of the emulsions. TS was shown to not only fill the interfacial gaps but also adsorb on the particle surfaces, contributing to interfacial wettability. With increasing TS concentration, interfacial tension decay is clearly observed. Further, TS endows the droplets with electrostatic repulsion and steric resistance, preventing their flocculation, coalescence, and oxidation. Finally, in vitro digestion experiments demonstrated that the presence of TS delayed the lipid digestion of the emulsions. [ABSTRACT FROM AUTHOR]