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Inspired by the viscoelastic displacement theory, we have developed a product called preformed particle gel (PPG) as conformance control agent to enhance oil recovery and control excess water production. The migration law of PPG suspension in porous media is related to its deep profile control and displacement capability. Laboratory experiments indicate that PPG suspension has good viscosity increasing, and the apparent viscosity decreases with the increase of shear rate. PPG suspension is mainly elastic, and its network structure makes it have certain shear stability. PPG particles realize migration in porous media in the way of “accumulation and blockage→pressure increase→deformation and migration”. When the ratio of the PPG particle size to the pore throat diameter δ ranges from 35.52 to 53.38, the particles can match through the porous medium. When the permeability difference of the parallel model is 5, PPG suspension has the highest profile improvement rate, 69.10%. PPG suspension can adjust the planar heterogeneity, and increase the oil recovery rate by 20.75%. The PPG suspension can effectively start “cluster"、 “film” and “blind end residual oil”, and has a high oil washing efficiency. The core NMR T2 spectrum shows that PPG suspension mainly reduces oil saturation in mesopores and macropores. After PPG flooding, the EOR capacity of small pores is the highest, 39.11%.

Particle Impact Drilling (PID) is a new technology to effectively improve the rate of penetration (ROP) for oil and gas drilling in hard and strongly abrasive formations. In this paper, numerical simulation method is used to analyse the motion characteristics and the modulation method of particle swarm in high-pressure tank for the particle injection system based on differential pressure ejection in PID. The numerical simulation results show that: when there is no modulation elements, the motion of particle swarm in the high-pressure tank follows an asymmetric funnel flow with pulsating state, which could be divided into vertical flow domain, fast flow domain, slow flow domain and stagnation domain. The unstable dynamic arching effect of the funnel flow, the viscous effect of the liquid bridge force and the collapsing effect of the particle swarm could probably lead to the blockage of the discharge port of the high-pressure tank. When the semiapex angles of the high-pressure tank decreases, the volume flow rate of particles increases and the stagnation domain becomes smaller, but it becomes easier to form arching and blockage. The modelling results indicate that the pulsation of the funnel flow is minimum when the semiapex angle is 45° without the mutilation element, which means the funnel flow of the particle swarm is relatively stable. By introducing a conical modulating element above the discharge port, the unstable funnel flow of the particle swarm could be transformed to an overall uniform flow. The modelling results indicate that the installation height of the modulation element has the greatest influence on the pulsation degree. The optimized parameters for the conical modulation element based on numerical modelling tests are 70° for the vertex angle, 35 mm for the length of the flank and 70 mm for the installation heigh.

The microstructure of primary Mg 2 Si and the interface of Mg 2 Si / α -Mg modified by Sn and Sb elements in an as-cast Mg-5Sn-2Si-1.5Al-1Zn-0.8Sb (wt.%) alloy were investigated. In the primary Mg 2 Si phase not only the Si atoms but also the Mg atoms could be substituted by Sn and Sb atoms, resulting in the slightly reduced lattice constant a of 0.627 nm. An OR of Mg 2 Si phase and α -Mg in the form of [ 001 ] Mg 2 Si ∥ [ 01 1 ¯ 1 ] α , ( 220 ) Mg 2 Si ∥ ( 0 1 ¯ 12 ) α was discovered. Between primary Mg 2 Si phase and α -Mg matrix two transitional nano-particle layers were formed. In the rim region of primary Mg 2 Si particle, Mg 2 Sn precipitates sizing from 5 nm to 50 nm were observed. Adjacent to the boundary of primary Mg 2 Si particle, luxuriant columnar crystals of primary Mg 2 Sn phase with width of about 25 nm and length of about 100 nm were distributed on the α -Mg matrix. The lattice constant of the Mg 2 Sn precipitate in primary Mg 2 Si particle was about 0.756 nm. Three ORs between Mg 2 Sn and Mg 2 Si were found, in which the Mg 2 Sn precipitates had strong bonding interfaces with Mg 2 Si phase. Three new minor ORs between Mg 2 Sn phase and α -Mg were found. The lattice constant of primary Mg 2 Sn phase was enlarged to 0.813 nm owing to the solution of Sn and Sb atoms. Primary Mg 2 Sn had edge-to-edge interfaces with α -Mg. Therefore, the primary Mg 2 Si particle and α -Mg were united and the interfacial adhesion was improved by the two nano-particles layers of Mg 2 Sn phase.

Laboratory experiments were performed to study the impact of the relative particle protrusion P/D (P is the protrusion height and D is the diameter of the target particle) on the mechanism of entra...

Aluminium-wood particle composites were formed by casting method. Different weight fractions of wood particle as reinforcement to the Aluminium alloys were used to produce the composites. The physical and mechanical properties such as density, impact strength, tensile strength, hardness and microstructure were investigated. The results showed that the density decreases with the percentage increase in reinforcement. Also, a significant enhancement in the ultimate tensile strength (UTS) of the composite compared to that of pure aluminium was achieved. The maximum UTS of the Aluminium -wood composite is 97.69 MPa and occurred at 20%wt wood particulate addition reinforcement while that of the unreinforced Aluminium is 40.189 MPa. The impact energy varies from 47.00 J to 89.00 J with a maximum value at 10%wt wood particulate addition while the hardness varies from 52.33BHN to 62BHN with a maximum value at 10%wt. All the mechanical behaviours investigated in the study generally showed that the Aluminium -wood composite exhibited better mechanical properties than the pure Aluminium. The microstructure examination revealed that the wood particles were uniformly distributed in the metal matrix composite.

To study the effects of the morphology of ZnO particles on the properties of asphalt binder and asphalt mixture, the micro ZnO particles with different morphologies (agglomerate, sphere, rod and flower), whose average size were 2 µm, were made by the homogeneous precipitation and hydrothermal methods. A series of tests, including the softening point, bending beam rheometer (BBR), dynamic shear rheological (DSR), Marshall test, rutting test and so on, were used for evaluating the properties of asphalt binder and asphalt mixture. The analysis of variance (ANOVA) and the maximum relative difference (MRD) were introduced to study the effects of the morphology of ZnO particles on the properties of asphalt binder and asphalt mixture. Finally, the optimal morphology of the ZnO particle was recommended. The results show that the morphology of the ZnO particle has a significant effect on the rutting factor, has an effect on the viscosity in the situation of the dosages of SBS are 0% and 4%, has no effect on the low temperature ability of asphalt binder. In terms of asphalt mixture, the morphology of the ZnO particle has a noticeable effect on the high temperature stability, has an effect on the low temperature ability, has almost no effect on the water stability of asphalt mixture. Furthermore, the rod-like ZnO particles are more conducive to promote the properties of asphalt binder and asphalt mixture. As a result, the rod-like ZnO particle is recommended.

Liquid–solid fluidized beds (LSFB) modeling validation is crucial for establishing design rules and monitoring tools. However, it generally relies on comparing global variables, which overlook dynamic features that influence reaction outputs. This work aims to implement time series analysis tools to compare Radioactive Particle Tracking data with a simulation consisting of Computational Fluid Dynamics coupled with Discrete-Element Method. Experiments have been performed in a pilot-scale LSFB of calcium alginate spheres fluidized with a calcium chloride solution. The Diks’ test indicates that the simulation can capture the LSFB behavior. It also allows diagnosing flow regime transitions from the simulation. Trends of solid dispersion coefficients and mixing times predicted by the simulation are in good agreement with the experiments.

Fe3O4 nanoparticles have been a research focus area for many years and have been applied in fields like medical treatment, catalysis and sensors. Particularly, they can be coated and dispersed in a solvent to prepare magnetic fluids. Magnetic fluid sealing is a high-performance sealing method but still not capable of extreme working conditions such as elevated temperatures. Here we present a new sealing method with nano-micro magnetic powders as a sealing medium. Fe3O4 particles with an average size of 20 nm, 200 nm and 25 μm are prepared by the chemical co-precipitation method. The fluid permeability of magnetic powders is estimated by Darcy’s Law. Finally, a static sealing prototype is designed and optimized based on magnetic field distribution analysis. Sealing experiments show a strong relevance between particle sizes and leakage rate. The mixture of nano and micron-sized Fe3O4 particles leads to a significant decrease in leakage rate, making magnetic powder sealing a promising novel sealing method.

In many energy and combustion applications, particles experience large temperature gradients, which can affect the coagulation process due to thermophoresis. This study presents a rigorous theory of thermophoretically modified Brownian coagulation in the entire particle size regime. The theoretical derivations are based on the kinetic theory for the free-molecular regime and the harmonic mean method for the transition regime. The coagulation kernels in different size regimes can be expressed as the basic Brownian coagulation kernel times an enhancement factor. The enhancement factor represents the coagulation rate enhancement induced by thermophoresis and is a function of specific dimensionless numbers. Based on the enhancement factor, the thermophoretic enhancement effects on particle coagulation are further analyzed under a wide range of gas and particle conditions. The results show that thermophoretic enhancement effects are ignorable in the free-molecular regime, but need to be considered in the continuum regime and the transition regime. In addition, the enhancement effects increase significantly with increase of gas temperature and temperature gradient while decrease with increase of gas pressure. The present study can improve understanding of thermophoretic effects on Brownian coagulation in the entire size regime and provide a useful tool to calculate the coagulation rates in presence of thermophoresis.

Gadolinium (III)-based T1 contrast agent have been widely used in clinical MRI. In this study, salicylic acid-gadolinium chelate was prepared via directly coordination reaction of gadolinium ion and salicylic acid. Then, three polyethylene glycols with different molecular weight were modified on the surface of salicylic acid-gadolinium by simple chemical coupling to construct three core-shell structural Gd based composites. The SEM and TEM characterization results show that the composite is a spherical particle with a diameter of about 100–200 nm. The longitudinal relaxation rate r1 of the Gal-PEG-2000 is 11.097 (mmol/L)–1/s, and the ratio of r2/r1 is as low as 2.53. The composite shows good liver and intestines MRI performances after being used in in vivo imaging, showing a good prospect of biological application.

As the demand for lithium-ion batteries increases, a better understanding of the complex phenomena involved in their operation becomes crucial. In this work, we propose a coupled thermo-chemo-mechanical model for electrode particles of Li-ion batteries. To this end, we start with a general finite strain continuum framework for the coupled thermo-chemo-mechanical problem and then narrow it down to cathode active particles of Li-ion batteries, particularly to lithium manganese oxide particles. Electrochemical kinetics at the surface of the particle and also heat generation due to current exchange are taken into account. Next, the numerical treatment of the problem using the finite element method is presented. Specific line elements are needed to evaluate the flux of ions at the surface of the particle. Finally, the performance of the proposed model is evaluated using a few representative boundary value problems., Deutsche Forschungsgemeinschaft, Projekt DEAL

This study aimed to quantitatively identify the influence of the block impact angle and block shape on the impact effect of reinforced concrete (RC) sheds. The smooth particle hydrodynamic (SPH) method and finite element method (FEM) were coupled and used to solve the simulation difficulty of large deformation of the sand buffer layer in the RC shed. SPH was used to simulate the sand buffer layer in the impact area that experienced large deformation. Concrete, reinforced, bedrock, block and sand buffer layer in the non-impact area were simulated by FEM. The accuracy of the coupled model was verified by the full-scale test data. Finally, the impact forces and the dynamic responses of the RC shed were analyzed, focusing on the effects of the block impact angle and shape. The numerical results show that the coupled SPH-FEM method is effective for simulating how block impacts the RC shed. The block impact angle and shape can significantly influence the normal and tangential impact forces. The design of the RC shed based on the assumption of blocks as free-falling spherical projectiles can lead to inaccuracy in some impact scenarios, and an appropriate correction was put forward in available empirical calculating formulae to include the effect of the irregular shape and impact angle of the block. The sand buffer layer dissipates a large part of the energy, which accounts for at least 58% of the initial impact energy.

In this paper, we present the design, development, and characteristics of the novel aerosol mass spectrometer ERICA (ERC Instrument for Chemical composition of Aerosols; ERC – European Research Council) and selected results from the first airborne field deployment. The instrument combines two well-established methods of real-time in situ measurements of fine particle chemical composition. The first method is the laser desorption and ionization technique, or laser ablation technique, for single-particle mass spectrometry (here with a frequency-quadrupled Nd:YAG laser at λ = 266 nm). The second method is a combination of thermal particle desorption, also called flash vaporization, and electron impact ionization (like the Aerodyne aerosol mass spectrometer). The same aerosol sample flow is analyzed using both methods simultaneously, each using time-of-flight mass spectrometry. By means of the laser ablation, single particles are qualitatively analyzed (including the refractory components), while the flash vaporization and electron impact ionization technique provides quantitative information on the non-refractory components (i.e., particulate sulfate, nitrate, ammonia, organics, and chloride) of small particle ensembles. These techniques are implemented in two consecutive instrument stages within a common sample inlet and a common vacuum chamber. At its front end, the sample air containing the aerosol particles is continuously injected via an aerodynamic lens. All particles which are not ablated by the Nd:YAG laser in the first instrument stage continue their flight until they reach the second instrument stage and impact on the vaporizer surface (operated at 600 ∘C). The ERICA is capable of detecting single particles with vacuum aerodynamic diameters (dva) between ∼ 180 and 3170 nm (d50 cutoff). The chemical characterization of single particles is achieved by recording cations and anions with a bipolar time-of-flight mass spectrometer. For the measurement of non-refractory components, the particle size range extends from approximately 120 to 3500 nm (d50 cutoff; dva), and the cations are detected with a time-of-flight mass spectrometer. The compact dimensions of the instrument are such that the ERICA can be deployed on aircraft, at ground stations, or in mobile laboratories. To characterize the focused detection lasers, the ablation laser, and the particle beam, comprehensive laboratory experiments were conducted. During its first deployments the instrument was fully automated and operated during 11 research flights on the Russian high-altitude research aircraft M-55 Geophysica from ground pressure and temperature to 20 km altitude at 55 hPa and ambient temperatures as low as −86 ∘C. In this paper, we show that the ERICA is capable of measuring reliably under such conditions.

The phenomenon of adsorption of solid particles at fluid interfaces to stabilize emulsions or foams have been known for more than a century. Today, particle-stabilized emulsions, often referred to as Pickering emulsions, are receiving growing attention as they are encountered in oil recovery and have long been used in personal care products and food industry. In the past 10 years the focus of the Pickering emulsion has also increasingly shifted to biomedical applications with thanks to novel syntheses of a wide range of biocompatible particle stabilizers. Here, a brief overview of the development of biocompatible particles is given for Pickering emulsion stabilization, including alginate, poly(lactic-co-glycolic acid) (PLGA), and protein-based particles. The materials capable of being prepared by templating from emulsion stabilized with biocompatible particles include colloidal capsules and hierarchically porous materials. It is hoped that the understanding gained from the recent intense activity in the field will enable more researchers to modify existing materials and design new formulations, which would be beneficial for exploring more biological applications.

Pickering emulsions are emulsions stabilized by colloidal surfactants, i.e. solid particles. Compared with traditional molecular surfactant-stabilized emulsions, Pickering emulsions show many advantages, such as high resistance to coalescence, long-term stability, good biocompatibility and tunable properties. In recent years, Pickering emulsions are widely applied in scientific researches and industrial applications. In this review, we focus on the influences of particle properties on Pickering emulsions, including particle amphiphilicity, concentration, size and shape, and summarize the strategies developed for the preparation of amphiphilic Janus particles. The applications of Pickering emulsions in food industry, cosmetic industry, material science, drug delivery, biomedical research and vaccine adjuvant will also be covered. Pickering emulsions are a unique system for multi-disciplinary studies and will become more and more important in the future.

Emulsions are liquid–liquid dispersions with one liquid phase dispersed in the other liquid phase as small droplets. Nanoemulsions are nano-sized emulsions with sizes ranging from tens to hundreds of nanometers, and have great potential applications in pharmaceutics, foods and cosmetics due to their attractive properties, such as small sizes, high surface area per unit volume, improved dispersion of active hydrophobic components and enhanced absorption. The article provides an overview of nanoemulsions for drug delivery, starting with an introduction of emulsion types, nanoemulsion preparation and nanoemulsion stability. Surfactants play critical roles in producing and stabilizing nanoemulsions. Different types of surfactants are summarized including small molecule surfactants, particle surfactants, phospholipids, peptide and protein surfactants. Then the applications of nanoemulsions as nanomedicine in drug delivery are presented. Finally, clinical applications of nanoemulsions are discussed.

Understanding of nanoplastic prevalence and toxicology is limited by imaging challenges resulting from their small size. Fluorescence microscopy is widely applied to track and identify microplastics in laboratory studies and environmental samples. However, conventional fluorescence microscopy, due to diffraction, lacks the resolution to precisely localize nanoplastics in tissues, distinguish them from free dye, or quantify them in environmental samples. To address these limitations, we developed techniques to label nanoplastics for imaging with Stimulated Emission Depletion (STED) microscopy to achieve resolution at an order of magnitude superior to conventional fluorescence microscopy. These techniques include (1) passive sorption; (2) swell incorporation; and (3) covalent coupling of STED-compatible fluorescence dyes to nanoplastics. We demonstrate that our labeling techniques, combined with STED microscopy, can be used to resolve nanoplastics of different shapes and compositions as small as 50 nm. The longevity of the dye labeling is demonstrated in different media and conditions of biological and environmental relevance. We also test STED imaging of nanoplastics in exposure experiments with the model worm C. elegans. These techniques will allow more precise localization and quantification of nanoplastics in complex matrices.SynopsisWe show that Stimulated Emission Depletion (STED) microscopy can be used to image single nanoplastics of different compositions and shapes. This will allow researchers to study environmentally-relevant nanoplastics and their interactions with organisms in relevant exposure scenarios.TOC Graphic

Triaxial experiments were conducted on granular materials presenting uniform, graded and fractal particle distributions in order to investigate how the broadness of the distribution affects the phenomenon of strain localisation. The shear band thickness evolution is assessed by digital image correlation (DIC) using three cameras placed at different angles around a transparent triaxial cell. From the field of deformation, Gaussian distributions have made it possible to fit the data satisfactorily and determine the shear band width evolution. The latter exhibits a rapid decrease in the softening regime until a residual value is reached in all cases. In the conditions of the experiments, it is shown that the residual shear band thickness scales with the mean grain size and the ratio between the two increases with the broadness of the distribution. Samples with uniform distribution exhibit an average residual thickness of ∼ 10D50, samples with graded distribution exhibit an average residual thickness of ∼ 12·5D50 and samples with fractal distribution exhibit an average residual thickness of ∼ 17D50.

Poor ductility is the primary concern of magnesium matrix composites (MMCs) inflicted by non-deformable ceramic particle reinforcements. Metal particles which melt at elevated temperature can be used as reinforcement to improve the deformation characteristics. Ti-6Al-4V particles reinforced AZ31 MMCs were produced through friction stir processing (FSP) which was carried out in a traditional vertical milling machine. The microstructural features as well as the response to external tensile load were explored. A homogenous distribution of Ti-6Al-4V was achieved at every part of the stir zone. There was no chemical decomposition of Ti-6Al-4V. Further, Ti-6Al-4V did not react with Al and Zn present in AZ31 alloy to form new compounds. A continuous strong interface was obtained around Ti-6Al-4V particle with the matrix. Ti-6Al-4V particles underwent breakage during processing due to severe plastic strain. There was a remarkable refinement of grains in the composite caused by dynamic recrystallization in addition to the pinning of smaller size broken particles. Dense dislocations were observed in the matrix because of plastic deformation and the associated strain misfit. Ti-6Al-4V particles improved the tensile behavior and assisted to obtain appreciable deformation before fracture. Brittle mode of failure was avoided.

The effect of mechanical strength of the dispersed particle gels (DPG) on their macro plugging performances is significant, however, little study has been reported. In this paper, DPG particles with different mechanical strengths were obtained by mechanical shearing of bulk gels prepared with different formula. Young's moduli of DPG particles on the micro and nano scales were measured by atomic force microscope for the first time. The mapping relationship among the formula of bulk gel, the Young's moduli of the DPG particles and the final plugging performance was established. The results showed that when the Young's moduli of the DPG particles increased from 82 to 328 Pa, the plugging rate increased significantly from 91.46% to 97.10% due to the distinctly enhanced stacking density and strength at this range. While when the Young's moduli of the DPG particles surpassed 328 Pa, the further increase of plugging rate with the Young's moduli of the DPG particles became insignificant. These results indicated that the improvement of plugging rate was more efficient by adjusting the Young’s moduli of the DPG particles within certain ranges, providing guidance for improving the macroscopic application properties of DPG systems in reservoir heterogeneity regulation.

Filter cake is critical to maintaining the stability of the excavation face of an underwater shield tunnel in a high-permeability stratum. In a high-permeability formation, generating an effective filter cake on the excavation face is difficult with a pure bentonite slurry, which penetrates the ground and may not achieve the required suspension pressure. Determining how to efficiently and quickly form a thin and low-permeability filter cake on the tunnel working face has become a key engineering problem in the construction of slurry shield tunnels in high-permeability strata. In this study, the relationship between slurry viscosity and the slurry pressure gradient of pure bentonite was established by performing slurry permeability experiments. The influence of slurry viscosity on the formation of the filter cake in a high-permeability formation was studied under different pressure gradients. In addition, the effect of additive particle size on the slurry filter cake formation was analyzed by introducing additives with different particle sizes to pure bentonite slurries with different viscosities. The test results indicate that (1) for the pure bentonite slurry, the critical initial pressure gradient can be used as a rough indicator of the formation of the filter cake, and the relationship between the critical maximum pore diameter and the average pore diameter of the formation can be compared to establish and analyze the formation law of the slurry filter cake; (2) adding particles to the slurry can enhance the effect of the pure bentonite slurry; and (3) adding coarse-grained materials can effectively improve the film-forming effect. The slurry is more compact when the particle size is close to the average pore size of the formation.

Acknowledgements: This work has been supported by EPSRC, via an industrial CASE award (for YC) with AWE (EP/R511870/1). © British Crown Copyright 2020/AWE., Tensile stress–strain testing and creep testing have been carried out on a polyurethane rubber, at three temperatures, with and without either particulate or short fibre alumina reinforcement. A previous paper reported concerning composites with particulate reinforcement and the present work is focused on the effect of the fibres. The samples were made via a blending and extrusion process that produced a certain degree of fibre alignment (along the direction of loading). Prior milling procedures were used to produce fibres with two different ranges of aspect ratio (with averages about 10 and 16). When expressed as true stress–strain relationships, all materials exhibit approximately linear responses. The dependence of stiffness on the volume fraction and aspect ratio of the reinforcement was found to conform well to the Eshelby model predictions. Moreover, the creep behaviour of all of the materials can be captured well by a Miller–Norton formulation, using the average matrix stress predicted by the Eshelby model. A striking conclusion is that it is both predicted and observed that short fibres are much more effective in reducing the creep rate than is the case with particles.

Background: Bacillus Calmette-Guerin (BCG) is a vaccine used to protect against tuberculosis primarily in infants to stop early infection in areas of the world where the disease is endemic. Normally administered as a percutaneous injection, BCG is a live significantly attenuated bacteria that is now being investigated for its potential within an inhalable vaccine formulation. This study investigates the feasibility and performance of two jet and two vibrating mesh nebulizers aerosolizing BCG and the resulting particle characteristics and residual viability of the bacteria postaerosolization. Methods: A jet nebulizer (Collison), outfitted either with a 3- or 6-jet head, was compared with two clinical nebulizers, the vibrating mesh Omron MicroAir and Aerogen Solo devices. Particle characteristics, including aerodynamic particle sizing, was performed on all devices within a common aerosol chamber configuration and comparable BCG innocula concentrations. Integrated aerosol samples were collected for each generator and assayed for bacterial viability using conventional microbiological technique. Results: A batch lot of BCG (Danish) was grown to titer and used in all generator assessments. Aerosol particles within the respirable range were generated from all nebulizers at four different concentrations of BCG. The jet nebulizers produced a uniformly smaller particle size than the vibrating mesh devices, although particle concentrations by mass were similar across all devices tested with the exception of the Aerogen Solo, which resulted in a low concentration of BCG aerosols. Conclusions: The resulting measured viable BCG aerosol concentration fraction produced by each device approximated one another; however, a measurable decrease of efficiency and overall viability reduction in the jet nebulizer was observed in higher BCG inoculum starting concentrations, whereas the vibrating mesh nebulizer returned a remarkably stable viable aerosol fraction irrespective of inoculum concentration.

This study aims to obtain nanoparticles by electrospinning method using xanthan gum (XG) and gelatine (GEL) polymers. For the development of these nanoparticles, ten different groups were produced. In some groups, nanofiber was obtained instead of particles. The nanofiber formation was determined in the 10 wt% GEL, 12 wt% GEL, 3 wt% XG, 8 wt% GEL + 3 wt% XG. 12 wt% GEL + 0.1 wt% XG groups. 4 wt% GEL + 1 wt% XG and 8 wt% GEL + 3 wt% XG groups showed nanoparticles structure. To assess the nanofibers chemical properties, Fourier transform infrared spectroscopy (FTIR) were used. Scanning electron microscopy (SEM) was used to characterize mechanical and morphological properties. Physical properties and swelling behaviours were examined to analyse the samples. As a result of the swelling test, 3 wt% XG was degraded, 10 wt% and 12 wt% gelatin groups started to degrade after the fourth day. Our work deduced that GEL/XG nanoparticles could use for carrier purposes. Also, this study was beneficial in finding the right ratios in the production of nanoparticles and nanofibers from the XG/GEL mixture by electrospinning. In addition, proper electrospinning parameters in nanofiber and nanoparticles production are also important results of the study and will be further used in developing composite nanostructures with regenerative or drug release capability.

The purpose of this study is to show the validity of the simulation result for particle charge and trajectory in an ESP with multiple wire electrodes.The ESP in this study has wires-and-plates configuration composed of three high-voltage application wire electrodes placed between grounded plate electrodes with a gap of 15 mm. The potential, the electric field intensity and the negative ion density were calculated by coupled analysis of Poison’s and current- continuity equations. The fundamental equation of flow field considering the ionic gas flow was a k-ω turbulence flow model. The charge of the particles was calculated from the differential equations of the electric and diffusion charging equations, taking into account the temporal and spatial electric field and ion density. The charged particle trajectory in the ESP was analyzed by an equation of motion considering fluid drag force and Coulomb’s force. In the measurement of the charged particle trajectory, oil mist as the tracer particle was mixed into the gas flow, and analyzed by a particle image velocimetry (PIV) using the software.As a result, the analysis value of the current density distribution on the surface of the grounded plate electrode agreed with the experimental value. The analysis results of the particle trajectory showed that the particle velocity increased, and moved toward the grounded plate electrode as the discharge power increased. The x and y components of particle velocity measured using PIV almost agreed with the simulated result. These results indicated the validity of the simulation result for charged particle trajectory, which was calculated by fitting the analyzed corona current to the experimental value, in the gas flow considering the ionic flow in an ESP with multiple wire electrodes.

Plug, a type of male mould in thermoforming, is mostly produced by conventional processes such as machining. However, in this study, plugs that are used in thermoforming were produced using Fused Deposition Modelling (FDM). Plugs were produced using Polylactic Acid (PLA) and Aluminium (Al) particle reinforced PLA filaments by a 3d printer. Plugs that are produced by FDM, were polished using 800, 1000, 1200, 1600 and 2000 grit sandpapers to reduce friction. Also, thermal effects such as temperature distribution on the region where the plug touches the plastic sheet, were investigated. It has been found that FDM can be a significant alternative for male mould production in thermoforming. Additionally, PLA filaments have great potential for tool production in thermoforming.

The super-structured nanodimensional apatitic particles have been limited explored for therapeutic applications. Furthermore, ion substituted super-structured nanodimensional apatitic particles have been rarely attempted, which motivated the present investigation. In the present work, F − and Cl − substituted hydroxyapatite (HAP) prepared via a facile and economical one-pot hydrothermal route were characterized for their structural, morphological and bioactive properties. The F − and Cl − anions (1 wt%) were individually substituted in hierarchically assembled nanostructured apatitic (HANA) particles and produced fluorine substituted Hydroxyapatite (FHAP) and chlorine substituted Hydroxyapatite (ClHAP) HANA particles, respectively. Besides comprehensive characterization, particles were systematically tested for their in-vitro ionic dissolution and drug-carrying abilities. Both FHAP and ClHAP nanoparticles exhibited monolithic apatitic structure, novel spherical morphology having substituted elements, mesoporous large surface area, and pore-volume with high thermal stability. Furthermore, both particles exhibited superior in-vitro bioactivity ability. Besides it, both FHAP and ClHAP nanoparticles exhibited superior drug loading and sustained drug release characteristics. Thus, this study presented the potentials of novel particle shapes with superior bioactivity and drug-carrying abilities, making them suitable for multipurpose therapeutic applications, including tissue regeneration and drug-carrying agents.

The development of hypersonic precooled combined cycle engine provides a reliable power system for the future intercontinental navigation and reusable space orbital transportation. The compact heat exchanger precooler is the key component of the cooling cycle system, which provides efficient heat management for the hypersonic engine. This investigation mainly focused on the manufacturing process of precooler, and the typical structure of the precooler, ultrathin-walled capillary structure, was facilitated by the vacuum brazing using the particle reinforced composite filler alloy. The effects of different types and contents of the reinforced particle on the spreading behaviour, microstructural evolution, mechanical performance changes were investigated in detail. During the cooling process, the nucleation and growth of the γ-Ni solid solution on the surface of the reinforced particles was the main reason for the microstructure homogenization. Compared to the Ni particles, the more obvious mechanical properties improvement could be achieved by using IN718 particles reinforced composite filler alloy. The tensile strength and elongation of the brazed ultrathin-walled structure present 9.36% and 47.27% higher than that using initial filler alloy. Moreover, the micro-hardness distribution result revealed that the reinforced particles reduced the overall micro-hardness of the brazed region, dispersed the eutectic structure and increased the hardness dispersion, which would reduce the stress concentration tendency and improve the structural properties.

The aim of this research is to study the effect of hydrophilic silica nanoparticles, sizes as CO2 foam stabilizer in the presence of nonionic TX100 surfactant. Two nanosilica sizes, 15 and 70 nm, have been examined thoroughly. Physisorption of TX100 on silica nanoparticles (nanosilica) was characterized by adsorption isotherm and surface tension measurement, while CO2 foams stability was quantified based on their foamability, foam stability, particle partitioning in the foams, and bubble sizes. Results show that direct contact of TX100 with nanosilica does altered the wettability of hydrophilic nanosilica surface, enable them to lengthen CO2 foams life at certain surfactant and nanoparticles concentrations. For 15 nm nanosilica, CO2 foam stability shows excellent performance at 0.1 and 0.5 wt% TX100 concentrations. As for 70 nm nanosilica, CO2 foam demonstrates longer lifetime at much lower TX100 concentration, 0.01 wt%. Without the presence of TX100, CO2 foams exhibit undesirable lifetime performances for both nanosilica sizes. Nanosilica partitioning in CO2 foams structures demonstrate consistent relation with contact angle measurement. Estimated bubble sizes shows insignificant effect on CO2 foams life. With the assists of nanosilica and TX100, enhanced oil recovery via CO2 foam injection succeeds in increasing oil production by 13–22% of original oil-in-place (OOIP).

Hypothesis Waterborne polyurethane (WPU) is a common colloidal dispersion that can aggregate in the aqueous phase to form nanoparticles with hydrophobic polyurethane chains as the core and hydrophilic ionic groups as the shell. Considering their structure and pH-responsive functional groups, WPU nanoparticles could be ideal particulate emulsifiers for preparing pH-responsive Pickering high internal phase emulsions (HIPEs). Experiments A series of anionic WPU with different content of 2,2-bis(hydroxymethyl)propionic acid (DMPA) side chains were synthesized via a polyaddition reaction. The DMPA content, size, ζ-potential, and interfacial behaviors of WPU were then investigated. Furthermore, the effects of particle concentration, internal phase fraction (ϕ), oil type, and pH values on the Pickering HIPEs’ morphology, stability, and rheological behaviors were systematically studied. Finally, we demonstrated the emulsification–demulsification process of WPU-stabilized Pickering HIPEs and discussed its mechanism. Findings Oil-in-water (O/W) Pickering HIPEs with tailored morphology and excellent pH-responsiveness were prepared from anionic WPU nanoparticles. The WPU concentration, ϕ, and oil type had a large impact on the formation and mean droplet size of the WPU-stabilized emulsions. Rheology analysis demonstrated that the strictly limited movement of droplets endowed the WPU-stabilized HIPEs with high stability, shear sensitivity, and excellent thixotropic recovery. By simply changing the aqueous-phase pH value, the WPU-stabilized HIPEs could undergo more than ten emulsification-demulsification cycles, as the physical and interfacial properties of WPU nanoparticles were pH-dependent. The excellent performance of the WPU-stabilized pH-responsive Pickering HIPEs exhibited their potential practical applications, such as for oil transportation and recovery, emulsion polymerization, and heterogeneous catalysis.

This work presents the effects of several factors on the mechanical strength of calcium phosphate cement (CPC) based on alpha tricalcium phosphate and correlates the results with the microstructure and percentage of conversion to hydroxyapatite. Conversion rate increased by raising the setting temperature in the studied range (4–90 °C), but the strength exhibited an increasing-decreasing trend due to changes in the morphology of hydrated crystals. Plate-like crystals were formed in the range of 22–60 °C, mechanically reinforcing the material, whereas the formation and refinement of needle-like crystals at higher setting temperature decreased the strength. Moreover, cements with dissimilar particle sizes had different optimal hydrolysis temperatures that resulted in the maximum strength. The finest powder led to higher strength at lower setting temperature due to the formation of a more compact crystal network and higher conversion. Therefore, optimization of powder particle size may allow to achieve the highest possible strength at room temperature, being beneficial for the production of the strong pre-set CPC-based implants without the use of energy. Furthermore, the particle size can be also engineered to produce formulations that develop the highest strength at physiological temperature, with application as injectable bone grafts. The incorporation and crosslinking of gelatine further increased the mechanical strength of pre-set cements by bridging the hydroxyapatite crystals, the setting temperature showing a similar effect to that of gelatine-free cements. In contrast, moisture decreased the strength and reduced the brittleness by the solvating intramolecular association between hydroxyapatite crystals and between gelatine molecules. Moreover, large cement bodies were slightly weaker than small ones, but the size effect was not statistically significant.

Investigations on the molten-pool sloshing behavior are of essential value for improving nuclear safety evaluation of Core Disruptive Accidents (CDA) that would be possibly encountered for Sodium-cooled Fast Reactors (SFR). This paper is aimed at synthesizing the knowledge from our recent studies on molten-pool sloshing behavior with solid particles conducted at the Sun Yat-sen University. To better visualize and clarify the mechanism and characteristics of sloshing induced by local Fuel-Coolant Interaction (FCI), experiments were performed with various parameters by injecting nitrogen gas into a 2-dimensional liquid pool with accumulated solid particles. It was confirmed that under different particle-bed conditions, three representative flow regimes (i.e. the bubble-impulsion dominant, transitional and bed-inertia dominant regimes) are identifiable. Aimed at predicting the regime transitions during sloshing process, a predictive empirical model along with a regime map was proposed on the basis of experiments using single-sized spherical solid particles, and then was extended for covering more complex particle conditions (e.g. non-spherical, mixed-sized and mixed-density spherical particle conditions). To obtain more comprehensive understandings and verify the applicability and reliability of the predictive model under more realistic conditions (e.g. large-scale 3-dimensional condition), further experimental and modeling studies are also being prepared under other more complicated actual conditions.

The influence of high-energy ball milling on structural, microstructural, and optical properties of TiO2 by modifying the nanoparticle size was studied. Five samples were extracted at different milling times (0, 2, 4, 8, and 13 h). The average particle sizes estimated by dynamic light scattering (DLS) were 205, 155.8, 116.8, 82.9, and 82.7 nm at 0, 2, 4, 8, and 13 h, respectively. X-ray diffraction analysis confirmed progressive broadening of the peaks as the milling time elapsed. Besides, a correlation was found between d spacing and the average crystal size. The UV–Vis diffuse reflectance spectra of TiO2 revealed a decrease in reflectance due to particle size reduction. Similarly, an alteration of the bandgap transition energy was presented, whose values gradually decreased from 2.966 eV to 2.861 eV for the sample without and with the maximum duration milling performed (13 h), respectively. Likewise, the SEM analysis showed a distribution in nanoparticle size that became more homogeneous and smaller average grain size as the milling duration was longer.

Cold spray is an attractive and rapidly developing process for additive manufacturing with high efficiency and precision, repairing and coating, especially in aircraft and aerospace applications. Cold spray additive manufacturing deposits micro-particles with large plastic deformation below their melting point, eliminating heat effect zone which could deteriorate the quality of repairing zone. The particle deposition in cold spray is a complex process which involves high strain rate, high contact pressure and high temperature. Here we develop, utilize and validate a thermo-mechanical model to provide a definitive way to predict deposition mechanics and surface deformation evolution for particle deposition process in cold spray additive manufacturing. Both a single particle and dual particles models were developed to investigate the contact interaction between particle/substrate and particle/particle. Different combinations of particle/substrate materials (Cu/Cu, Al/Al, steel/steel, and nickel/nickel) and process parameters were considered in this study. The experimental study was conducted to validate simulation results, providing useful information for understanding the limitations and challenges associated with cold spray additive manufacturing. The framework provides insights into improving the quality and precision of stress/strain formation, particle interactions and particle deposition in cold spray additive manufacturing process.

Hollow materials have many advantages when acting as electromagnetic wave (EMW) absorber, such as excellent impedance matching properties, rich micro-interfaces and light weight. In this work, a novel hollow particle with double-shell composed with CuS and Mn(OH)2 is synthesized by coordination etching, precipitation and sulfuration using tetrakaidecahedral Cu2O as template. These hollow particles are expected to be used as improved EMW absorption property at an ultra-wide band. In this hollow particle, tetrakaidecaheral CuS acts as inner shell and Mn(OH)2 acted as outer shell, thus having rich heterogeneous interfaces which induce strong interfacial polarization. Moreover, the lower electrical conductivity and loose structure of the Mn(OH)2 shell facilitates the entry of EMW into the absorbers, and the hollow structure in this particle is beneficial to improve the impedance matching according to Maxwell-Garnett (MG) theory. Therefore, hollow CuS@Mn(OH)2 particles with double-shell exhibit excellent EMW absorption performance. The effective absorption bandwidth (reflection loss (RL) ≤ −10 dB) is 6.88 GHz (from 11.12 GHz to 18 GHz) at 2.3 mm thickness of sample.

Fully resolved numerical simulations of a micron-sized spherical particle residing on a surface with large-scale roughness are performed by using the Lattice–Boltzmann method. The aim is to investigate the influence of surface roughness on the detachment of fine drug particles from larger carrier particles for transporting fine drug particles in a DPI (dry powder inhaler). Often the carrier surface is modified by mechanical treatments for modifying the surface roughness in order to reduce the adhesion force of drug particles. Therefore, drug particle removal from the carrier surface is equivalent to the detachment of a sphere from a rough plane surface. Here a sphere with a diameter of 5 μm at a particle Reynolds number of 1.0, 3.5 and 10 are considered. The surface roughness is described as regularly spaced semi-cylindrical asperities (with the axes oriented normal to the flow direction) on a smooth surface. The influence of asperity distance and size ratio (i.e. the radius of the semi-cylinder to the particle radius, Rc/Rd) on particle adhesion and detachment are studied. The asperity distance is varied in the range 1.2

The specific luminescence behavior of crystalline oxide particles doped with rare earth ions strongly depends on the initial composition of the host material and synthesis conditions. This issue is especially significant for non-isovalent doping in the crystal lattice. In this case, the formation of the structure is accompanied by the formation of point defects serving as charge compensators. The work is devoted to the synthesis of CaWO4:Nd3+ particles in the salt melt (modified Pechini method) and the study of structural and luminescent properties under varying synthesis conditions. It was found that temperature and duration of heat treatment in the salt melt (KCl) affected the crystal structure, the size of coherent scattering regions, luminescence intensity, and lifetime. An increase of heat treatment temperature led to a reduction of luminescence intensity and lifetime due to the formation of point defects. The optimal synthesis conditions for obtaining the highest luminescence intensity of CaWO4:Nd3+ crystalline particles in salt melt were found to be the following Т1= 600 °C; t1=2 h (the stage of polymer gel thermal treatment), Т2= 800 °C; t2=1 h (the stage of thermal treatment in KCl salt melt). As-synthesized CaWO4:Nd3+ powders contain both coarse and fine fractions. However weak particle agglomeration allowed obtaining a water dispersion with individual nanoparticles (up to 200 nm) after ultrasonic treatment. According to the obtained results, the synthesized material is characterized by high luminescence intensity and high dispersion, and promising as fluorescent thermometers and biological labels.

Calcium alumino-titanate (CAT), a secondary material obtained from ferrotitanium slag, was used as a hibonite source to prepare CaAl12O19–MgAl2O4–Al2O3 castables. The restructuring effect of CAT aggregate was compared by replacing tabular alumina aggregates with CAT aggregates of different particle sizes. The effects of CAT particle size on cold mechanical strength and thermal shock resistance of CaAl12O19–MgAl2O4–Al2O3 castables were studied. The results showed that CAT aggregates with particle size of 5–3 or 3–1 mm led to more internal cracks or pores and reduced the cold mechanical strength of the castable samples fired at 1600 °C for 3 h. The use of CAT aggregates with particle size of 1–0 mm led to the formation of a well-bonded CAT aggregate and matrix, improving the cold mechanical strength and thermal shock resistance of the castable samples fired at 1600 °C for 3 h. The enhancement mechanism of fine CAT aggregates in this process was proposed based on the sintering of the matrix–aggregate interface with the formation of Ca(Al, Mg, Ti)12O19.

Superhydrophobic coatings have potential applications in fouling resistance, self-cleaning, waterproofing, and drag reduction. In this work, using a facile brush-painting method for outdoor application, superhydrophobic silica coating layers were developed with high contact angle above 150°, high light-transmittance above 90 %, and strong weather resistance via three strategies: (i) hexadecyltrimethoxysilane-modified SiO2 (H-SiO2) particle agglomeration in colloidal coating solutions, and the formation of (ii) two-dimensional (2D) mud-crack patterns and (iii) three-dimensional (3D) micro-bumps. First, particle agglomeration was optimized in a mixed solution of water and ethanol with a relative permittivity of e = 48.0. Second, high transmittance and full-covered hydrophobic properties were achieved from the silica coating layers with 2D mud-crack patterns. Third, maximal contact angle of 152.6° was obtained from the superhydrophobic silica coating layers consisting of heterogeneous 3D micro-bumps on the 2D mud-crack patterns. The superhydrophobic coating layers exhibited high light-transmittance of 90.2 % and near-zero sliding angle, making them suitable for use as self-cleaning solar panels. These brush-painted superhydrophobic silica layers have potential uses in industrial coating applications by providing self-cleaning capability, weather resistance, flexibility, and transparency.

During twin screw granulation (TSG), small particles, which generally have irregular shapes, agglomerate together to form larger granules with improved properties. However, how particle shape impacts the conveying characteristics during TSG is not explored nor well understood. In this study, a graphic processor units (GPUs) enhanced discrete element method (DEM) is adopted to examine the effect of particle shape on the conveying characteristics in a full scale twin screw granulator for the first time. It is found that TSG with spherical particles has the smallest particle retention number, mean residence time, and power consumption; while for TSG with hexagonal prism (Hexp) shaped particles the largest particle retention number is obtained, and TSG with cubic particles requires the highest power consumption. Furthermore, spherical particles exhibit a flow pattern closer to an ideal plug flow, while cubic particles present a flow pattern approaching a perfect mixing. It is demonstrated that the GPU-enhanced DEM is capable of simulating the complex TSG process in a full-scale twin screw granulator with non-spherical particles.

Effective thermal conductivity of soils can be enhanced to achieve higher efficiencies in the operation of shallow geothermal systems. Soil cementation is a ground improvement technique that can increase the interparticle contact area, leading to a high effective thermal conductivity. However, cementation may occur at different locations in the soil matrix, i.e. interparticle contacts, evenly or unevenly around particles, in the pore space or a combination of these. The topology of cementation at the particle scale and its influence on soil response have not been studied in detail to date. Additionally, soils are made of particles with different shapes, but the impact of particle shape on the cementation and the resulting change of effective thermal conductivity require further research. In this work, three kinds of sands with different particle shapes were selected and cementation was formed either evenly around the particles, or along the direction parallel or perpendicular to that of heat transfer. The effective thermal conductivity of each sample was computed using a thermal conductance network model. Results show that dry sand with more irregular particle shape and cemented along the heat transfer direction will lead to a more efficient thermal enhancement of the soil, i.e. a comparatively higher soil effective thermal conductivity.

As a state-of-the-art secondary battery, lithium-ion batteries (LIBs) have dominated the consumer electronics market since Sony unveiled the commercial secondary battery with LiCoO2 as the negative electrode material in the early 1990s. The key to the efficient operation of LIBs lies in the effective contact between the Li-ion-rich electrolyte and the active material particles in the electrode. The particle properties of the electrode materials affect the lithium ion diffusion path, diffusion resistance, contact area with the active material, the electrochemical performance and the energy density of batteries. To achieve satisfied comprehensive performance and of LIBs, it is not only necessary to focus on the modification of materials, but also to balance the properties of electrode material particles. Therefore, in this review, we analyze the influence of particle properties on the battery performance from three perspectives: particle size, particle size distribution, and particle shape. A deep understanding of the effect and mechanism of particles on electrodes and batteries will help develop and manufacture practical LIBs.

In recent years, phase change material emulsions (PCMEs) with enhanced energy storage capacities and good flow characteristics have drawn significant attention. However, due to the thermodynamically unstable nature and tiny particle confinement, the nanomaterial modification strategies at PCM/water interface to improve stabilities and reduce supercooling of nano-sized PCMEs (NPCMEs) are very limited and challenging. Herein, we report a facile strategy for constructing MXene-decorated NPCME with good stability, little supercooling, and high thermal conductivity by self-assembly of MXene nanosheets at PCM/water interface. The concentrations of MXene have great influences on the average droplet diameters, stabilities, and thermophysical properties of the NPCMEs. The results show that the PCMs have been well dispersed into the water in the form of quasi-spherical droplets, with average droplet diameters of 242–805 nm. The thermal conductivity of 10 wt% n-tetradecane/water NPCME containing 9 mg ml-1 MXene is 0.693 W m-1·K-1, achieving an enhancement by 15.5%, as compared to that of water. Besides, the MXene-decorated paraffin/water NPCMEs exhibit little supercooling and enhanced heat storage capacities. More importantly, this facile self-assembly strategy opens a new platform for preparing high-performance NPCMEs, which can be used as novel heat transfer fluids for thermal energy storage systems.

CdO nanoparticles (CdO NPs) were synthesized utilizing urea-assisted auto-combustion (AC) and microwave combustion (MC) methods. The structural, thermal, optical, morphological, and compositional analysis of the prepared samples were investigated after they were heat treated at 350 °C. The impact of heat treatment and the method of synthesis on their physicochemical properties were investigated. XRD was used to determine the phase, crystallite size, and lattice constant of CdO NPs. The modification of the phase and crystallite size of CdO NPs indicates the impact of the heat treatment and synthesis process. The annealing process raises the crystallite size from 28 nm to 45 nm for the auto combustion approach and from 24 nm to 40 nm for the microwave combustion method. Under heat treatment, the energy band gaps of CdO NPs from auto combustion method and microwave combustion method samples were determined to be 2.09 eV and 1.65 eV, respectively. The surface morphology of CdO NPs was documented by SEM, indicating that the particle's morphology was modified by the synthesis procedure. The nanoscale range of the particles is confirmed by TEM micrographs of annealed CdO NPs, which is closely matched with the crystallite size derived from XRD. TG-DTA was used to examine the thermal characteristics of annealed CdO NPs.

Understanding the discharge characteristics as well as the detectability of metal particles in the GIS will be helpful in improving its safety and reliability. In this paper, the pulse current and UHF signals generated by PDs of metal particles of different lengths at different positions on a real spacer surface were studied. The PD characteristics and detectability of the metal particles on the spacer surface were obtained while the detection limitation was also discussed. It is found that under PD test condition, the apparent charge of the PDs is less than 1 pC for particles smaller than 5 mm, and the conventional PD detection method have limitations in detecting these small defects. Under operation condition, only the apparent charge of particles larger than 8 mm can exceed 1 pC, which means it is difficult to detect the particles smaller than 8 mm in field. However, even the 5-mm-long particle will be harmful to the GIS. Meanwhile, it is also been found that the detection sensitivity also has a great influence on the judgement of PD severity. This study is of great interest for understanding the PD characteristics, discharge levels, and detectability of small metal particles on spacer surface

Hypothesis The stability of fluid–fluid interface is key to control the displacement efficiency in multiphase flow. The existence of particles can alter the interfacial dynamics and induce various morphological patterns. Moreover, the particle aggregations are expected to have a significant impact on the interface stability and patterns. Experiments Monodisperse polyethylene particles of different sizes are uniformly mixed in silicone oil to form the granular mixtures, which are injected into a transparent radial Hele-Shaw cell through different strategies to obtain the homogeneous and inhomogeneous (with particle aggregations) initial states. Subsequently, a systematic study of morphology and interface stability during the withdrawal of granular mixtures is performed. Findings For homogeneous mixtures, we observe earlier onset of fingering, more fingers and lower gas saturation at breakthrough than for pure fluid with equivalent viscosity. This effect can be attributed to the particle-induced perturbations. For inhomogeneous mixtures, particle clusters and bands significantly enhance the interface instability. Furthermore, we find that particle deposition due to liquid film entrainment occurs above a critical local flow velocity, and we elucidate the responsible mechanism through force balance analysis and the thin film theory. This work could be of practical significance in geoenergy and industrial applications.

Particle morphology has great influence on mechanical behaviour and hydro/thermal/electrical conductivities of granular materials. Surface reconstruction and mesh generation are critical to consider realistic particle shapes in various computational simulations. This study adopts the combined finite- discrete element method (FDEM) to investigate single particle crushing behaviour. Particle shapes were reconstructed with spherical harmonic (SH) in both spherical and Cartesian coordinate systems. Furthermore, the reconstructed surface mesh qualities in two coordinate systems are investigated and compared. Although the efficiency of the two SH systems in reconstructing star-like shapes is nearly identical, SH in Cartesian coordinate system can reconstruct non-star-like shapes with the help of surface parameterisation. Meanwhile, a higher triangular mesh quality is generated with spherical coordinate. In single particle crushing tests, the low mesh quality produces more fluctuations on load–displacement curves. The particles with more surficial mesh elements tend to have a lower contact stiffness due to more contact stress concentrations induced by complexity of morphology features and more volumetric tetrahedral elements. The fracture patterns are also influenced by mesh quality and density, e.g. a particle with fewer mesh elements has a simpler fragmentation pattern. This study serves as an essential step towards modelling particle breakage using FDEM with surface mesh directly from SH reconstruction.