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In the present paper, we have studied the dependence of thermal conductivity on shape, size and dimension of nanomaterial. By using the quantitative expression of melting temperature, the expression for thermal conductivity is deduced in this work. Kapitza resistance term is also considered in the study to better explain the thermal conductivity variation in nanomaterials with scattering effect on thermal properties. The thermal conductivity is found to decreased as size of nanomaterials decease. The variation in thermal conductivity with size is calculated for nanowire, nanofilm, spherical, regular tetrahedral particle, regular octahedral particle, and regular icosahedral particle shapes. The results calculated in the present work are compared with the available experimental results to judge the validity of the present model.

Abrasive flow jet machining (ASJM) is modern manufacturing technique which uses comparatively low-pressure abrasive flow jet for machining various machined surfaces like holes, channels and intricate shapes which is not possible from conventional machining processes. The effect of abrasive particle concentration on the impacting slurry velocity on the surface was examined in the present CFD simulation, resulting in target surface erosion. To predict the impact velocity of abrasive particles hitting the surface, a 2D CFD model was used. The depth of machined surface, surface irregularity and surface removal rate at normal incidence mainly depend on the KE of particle, impact angle, etc. in line with previously published research work on highly pressurised air and water driven abrasive jet. In the present work CFD simulation is performed to predict the effect of solid particle concentration on the impacting slurry jet velocity at the target surface and also turbulence kinetic energy near the surface is studied. As per the CFD results the simulation model predictions the velocity of impacting particle goes on decreasing due to internal frictional resistance between solid and liquid phase and it shows scope of further parametric analysis in this area.

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.

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.

This article focused on the emission probability of the grey particles with black particles emitted in the interaction of 84Kr (as a projectile) having incident kinetic energy 1 GeV per nucleon with nuclear emulsion detector (as target detector). This study show that the emission probability of grey particles is depending on the number of emitted black particles.

Ferrite Cobalt (CoFe2O4) is a recognized attractive material with normal implementation and normal size of polarization. It has unmistakable substance security and motorized hardness. It is an eager promoter for the strategy of tactile gadgets and actuators, as an authoritative fixing, attractive medication gadgets electrical and having a broad scope of researching in materialistic innovation or science for mechanical uses and applications. These nanoparticles cobalt and ferrite on an ensnared viably handled on surrounding temperature by a basic process of co-precipitation. This precious stone structures and architecture of image was controlled through X-ray diffraction and SEM. The range of XRD affirms that composite nano-particles were shaped by ideal structure of spinel. This normal pace of precious stones was controlled through methods for Modified Scherer (54 nm) and Williamson-Hall (49 nm) techniques. A SEM view demonstrated nanoparticles CoFe2O4 being assembled in close-by structures. This visual and bond highlights was depicted by FTIR and UV–Vis Spectrum. As the temperature of the production rises, so does the magnetics period for the NPs and the magnetization of the concentration improves monotonously from 2.6 μB to 16 μB plus from 37 to 66 emu/g. According to the actions of both SPM and attendance of a dead layer (surface amorphous shell layer), which systemically decreases as the synthesis temperature increases, the optimum curve-appropriate of M-H statistics is due to the reduced particle/particle interaction.

In this manuscript we have focused on the shower particle characteristics produced at relativistics energy. We have also investigated the inequality of the shower particles emitted out of the interactivity of the projectiles with discrete target nuclei of the emulsion detector. In this investigation we have remarked that as we move to heavier target nuclei the release probability of shower particles is increases.

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

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.

Supercritical water (SCW) fluidized bed reactors convert biomass to fuels without pollutants emission. In this work, experimental studies were carried out to investigate voidage distribution in an SCW fluidized bed by capacitance probes. Quartz sands with different particle sizes were fluidized by SCW under system pressure of 20–27 MPa and temperature of 410–570 °C. The effect of operation conditions on voidage distributions of the emulsion phase (e.g. averaged voidage and probability density) is discussed. A predicting correlation between voidage and superficial velocity in emulsion phase is proposed. The relative error of the correlation is within ±25%. These research results provide useful guidance for the optimization of supercritical water gasification technology.

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 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.

Gate valve is mainly used to turn on or turn off the pipeline in pneumatic conveying. When the gate valve is fully open, the particles are easy to collide with the cavity rear wall and enter into the cavity, resulting in particles’ accumulation in the cavity. The particles in cavity will accumulate between the cavity bottom and the flashboard bottom wall and prevent the gate from turning off normally. Meanwhile, the particles’ collision with cavity rear wall will cause serious erosion. Both the particles’ accumulation and erosion will cause the poor sealing of the gate valve, further resulting in the leakage of the pipeline system. To reduce the particles’ accumulation in cavity and erosion on cavity when the gate valve is fully open, we simplify the gate valve into a cavity structure and study it. We find that adding a slope upstream the cavity can effectively reduce the particles’ accumulation in the cavity and the erosion on the cavity rear wall. In this work, Eulerian–Lagrangian method in commercial code (FLUENT) was used to study the gas–solid two-phase flow and erosion characteristics of a cavity with a slope. The particle distribution shows that the particles with Stokes number St = 1.3 and St = 13 cannot enter the cavity due to the slope, but the particles with St = 0.13 enter the cavity following the gas. For St = 13, the particles collide with the wall many times in the ideal cavity. Erosion results show that the slope can transfer the erosion on cavity rear wall to the slope and reduce the maximum erosion rate of the wall near the cavity to some degrees.

Coating of particulate materials in fluidized beds is a widely used technique to eliminate particle agglomeration, provide slow release of an active substance, or protect active ingredients. When thin polymer shells are applied on a particle surface, it is important to determine the process parameters that provide coating uniformity. In this study, the degree of coverage, defined as the fraction of the coated surface of the particles, is proposed as a quantitative criterion of coating uniformity. A new model for the batch fluidized-bed coating process is presented. The model allows prediction of the function of particle distribution according to the degree of coverage at a given process time and thereby enables assessment of coating uniformity. An algorithm for the numerical solution of model equations for a batch fluidized-bed coater is described. The influences of the main process parameters on the coating uniformity were shown.

Vibrating separation is a significant method for liquid–solid separation. A typical example is the vibrating screen to dewater wet granular matter. The properties of granular matter and the vibrating parameters significantly affect the separation efficiency. This study investigates the effect of vibration parameters in separation based on the breakage of large-scale liquid bridge numerically by using a calibrated simulation model. Through analysing the simulation results, the liquid bridge shape and the volume between two sphere particles for various particle sizes and particle distances were studied in the static condition under the effect of gravity. The results show a general reducing trend of liquid bridge volume when the radius ratio of two particles increases, particularly when the ratio increases to 5. Additionally, a set of vibrating motion was applied to the liquid bridge in the simulation model. A group of experiments were also performed to validate the simulation model with vibration. Then, the effect of vibrating peak acceleration, distance between spheres and radius on the separation efficiency which was reflected by the residual water were investigated. It is found that separation efficiency increased obviously with the peak acceleration and the increase slowed down after the peak acceleration over 1 m/s2.

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.

Screw conveyors are widely employed in industrial fields for conveying bulk materials. The shearer drum which uses the screw conveying principle is responsible for excavation and conveying coal particles onto the chain conveyor. Screw conveyor performance is affected by potential factors, such as the blade axial tilt angle and style, core shaft form and diameter. The effect of blade axial tilt angle on the conveying performance was investigated with the help of DEM. In the case of the screw conveyor, the mass flow rate, and particle axial velocity increased with increasing positive axial tilt angle, and declined with increasing negative axial tilt angle. In the case of the drum, the mass flow rate, particle axial velocity, and loading rate first increased and then decreased with increasing positive axial tilt angle, and decreased with increasing negative axial tilt angle. These results can be considered as a benchmark for screw conveyor and drum structural designs with axial tilt screw blades.

Effects of some important structural parameters, i.e. slat pitch, and layout position, on dynamic forces acting on the baffles were examined in the fluidized bed of FCC particles operating under different superficial gas velocities. The experimental baffles were made of multiple inclined slats. We found that the forces acting on the baffles decreased significantly with reducing pitch between the slats. For the baffles with a small slat pitch, the forces acting on the baffles increased slightly and then decreased with increasing superficial gas velocity, which is very different from the measured results of a single slat or tube immersed in fluidized beds. The different results are greatly related to the appearance of the “gas cushion” beneath the baffles, whose height increases with increasing superficial gas velocity. On the other hand, a region with stronger particle circulation induced by the inclined slat array was observed in the experiments. The slat near the wall and located below the region of downward-flowing particles was found to be subjected to the severest forces. Therefore, the slats located in similar locations of industrial baffles are suggested to be reinforced to increase their structural strength.

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

Geological disasters such as slope failure and landslides can cause loss of life and property. Therefore, reproducing their evolution process is of great importance for risk assessment and mitigation. The recently developed SIMSAND critical state sand model combined with the smoothed particle hydrodynamics (SPH) method is adopted in this work to study slope failure under large deformations. To illustrate the efficiency and accuracy of the SIMSAND-SPH approach, a series of slope collapse studies using the discrete element method (DEM) considering various particle shapes (i.e. spherical, tetrahedral and elongated) is adopted as benchmarks. The parameters of the SIMSAND model are calibrated using DEM triaxial tests. In comparison to the DEM simulations, the runout distance and final slope height are well characterized with the SIMSAND-SPH approach with less computational cost. All comparisons show that the SIMSAND-SPH approach is highly efficient and accurate, which can be an alternative numerical tool to simulate real scale granular flow.

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.

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.

The integrity and regularity of pore morphology play an important role in determining the mechanical properties of the metallic foam materials. The conventional methods on refining pore morphology are mainly focused on the optimization of fabrication techniques, however, they are usually inconvenient and complicated. Recently, incorporating nano reinforcement is considered to be a suitable way to fabricate metallic composite foams accompanied by optimized pore morphology and enhanced mechanical properties. In this work, through a facile and rapid powder metallurgy foaming method, the aluminum-silicon (Al-Si) alloy composite foams reinforced by graphene nanosheets (GNSs) are successfully fabricated. The microstructure analyses reveal that, for the Al-Si alloy foams incorporating the GNSs (GNSs/Al-Si composite foams), the pore size is transformed to be smaller, the pore size distributions become more homogeneous and the pore shape is also refined to a regular and roundish state. Meanwhile, the shape of Si precipitates is found transforming from an irregular long strip (length of ~20 μm, width of ~5 μm) to a fine particle state (diameter of ~5 μm). Moreover, the compressive testing results show that, the 0.4 wt% GNSs/Al-Si composite foams own the optimal compression stress of 11.7 ± 0.5 MPa, plateau stress of 10.0 ± 1.0 MPa and energy absorption capacity of 6.8 ± 0.7 MJ/m3, which have improvement of 58.1%, 53.8% and 51.1% in comparison with the Al-Si alloy foams counterpart, respectively. The present findings may pave a new way for developing new generation of metallic composite foams that with stable microstructure and excellent mechanical performance.

An extensive literature review shows a lack of comprehensive research work regarding the distribution of poly-disperse solids in Newtonian and non-Newtonian fluids. In this investigation, the efficiency of a coaxial reactor (a high rotational speed central axial-flow impeller and a low speed wall-scrapping anchor impeller) in distributing the poly-disperse particles in water (Newtonian) and carboxymethyl cellulose (CMC) solutions (non-Newtonian) was assessed employing a flow-visualization methodology (electrical resistance tomography). The solids hold-up profiles were measured by making use of the tomograms. The critical rotational speed of a central stirrer in achieving the just suspension state for various operating conditions was determined via measuring the particle bed height. The extent of axial distribution of poly-disperse particles was characterized utilizing the data from tomography measurement. The effects of some key variables such as poly-disperse ratio, impeller rotational mode, and CMC loading on the distribution of poly-disperse particles in coaxial agitated systems were extensively analyzed. The capability of the coaxial impellers in distributing the poly-disperse solids in water and CMC solutions was compared to that with a traditional single agitator. Overall, an improved level of distribution of poly-disperse particles in water and CMC solutions was obtained at lower power usage employing the coaxial impellers.

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.

Hydroxyapatite (HAP), which is chemically represented as (Ca10(PO4)6(OH)2), is one of the main inorganic material of vertebrate bone and teeth. The bioceramic material is used as a substitute for deficient bone tissue because of its similarities to crystallographic and chemical composition of teeth and bone. HAP is extensively used in various biomedical applications because of its excellent properties, such as bioactivity, non-toxicity, biocompatibility, non-immunogenicity and osteoconductivity. In this work, hydroxyapatite powder was synthesized using polyoxyethylene lauryl ether (Briji-35) as a surfactant and dimethyl sulfoxide as a primary surfactant through microemulsion method. The obtained products were characterized by FTIR, XRD and SEM. The result indicated that, the Briji-35 played an important role for the formation of nano-hydroxyapatite particle with good crystallinity and particles with uniform morphology besides controlling the particle size of nano-HAP. The biomedical application studies of the as-synthesised material are yet to be studied.

A new method was proposed for the evaluation of the efficiency of microwave heating asphalt mixtures and the influences of density and particle sizes of reclaimed asphalt pavement (RAP). Temperature distributions of asphalt mixtures with density of 1.35 and 2.02 t/m3 and particle size ranges of 3–6, 6–9.5, and 9.5–13.2 mm along the direction of microwave propagation were experimentally evaluated and the results obtained for the efficiency of microwave heating RAP with different densities and particle sizes were compared based on the proposed method. Also, increase of the particle size of RAP with basalt aggregates higher ability of microwave absorption.

Non-uniform sand retention behavior often occurs to the serviced screen deteriorating erosion. However, this phenomenon is poorly understood. This paper presents a numerical study of the sand retention on wire-wrapped screens, with special reference to non-uniform behaviors. This is done by the combined approach of computational fluid dynamics (CFD) and discrete element method (DEM). The validity of the model has been validated for dry and wet sand screen systems. It is used here to study sand retention behaviors at different solid concentrations and particle size distributions (PSD). Via this model, five distinct sand retention modes are identified: No sand retention (Mode I), partial sand retention (Mode II), sand retention with slow sequential bridging (Mode III), sand retention with fast sequential bridging (Model IV) and sand retention with instantaneous bridging (Mode V). Modes II and III belong to non-uniform sand retention, which develops strong local flows that induce local erosion or hot spot on the screen. A phase diagram is introduced to predict these five modes and their transition with respect to solid concentration and PSD. Additionally, the predicted flow and force structures are analyzed in detail. The results indicate that the bridging over a slot heavily relies on the particle accumulation on the screen. A new screen with a converging slot configuration is proposed to improve this particle accumulation. This improvement helps develop uniform sand retention on the screen.

This paper aims to systematically investigate the cataracting-centrifuging transition in a rotary drum involving spherical and nonspherical particles by using the Multiphase Granular Eulerian Model (MGEM). The effects of drum length and particle shape on the cataracting-centrifuging transition behavior were analyzed. The results showed that drum length plays an important role in the cataracting-centrifuging transition, although most related works in the literature do not consider this. The particle shape also significantly affects the cataracting-centrifuging transition behavior. Nonspherical particles required lower rotation speeds than spherical particles to reach the centrifuging condition. The particle shape was shown to be related to the critical solid fraction (αsc) from Schaeffer’s model, although further investigations are required to completely correlate particle spherecity with critical solid volume fractions.

Cu nanowires covered by Ag particles is studied for potential applications in the next-generation microelectronics. To date, the deformation mechanism in the Cu Ag core-particle is not clear. Here, molecular dynamics simulation is used to describe the Cu Ag core-particle system. The results show that the equilibrium structure of Ag particles is reconstructed, when the particle ≤1.0 nm. At low temperature (1 K) indicate that three different deformation processes take part in the core-particle structure, depending on the size of Ag particles. When the particle diameter ≤2.0 nm, the prevailing deformation mechanism is the emission of dislocations from the Cu surface. For the particle diameters ranging from 3.0 to 6.0 nm, the emission of misfit dislocations from the Ag Cu interface is the dominant deformation mechanism. If the Ag particle ≥6.0 nm, the deformation mechanism can be characterized by the slip band, consisting of the dislocations and amorphous atoms. For elevated temperatures (2–400 K), the mechanical properties of the Ag Cu core-shell system are nearly independent of temperature, whereas the structure with particles larger than 2.0 nm showed a strong dependence of its mechanical properties on temperature. Based on the results, the diameter-temperature plastic deformation map is proposed.

Hydroxyapatite (HAP) [Ca10(PO4)6(OH)2] is an excellent bio-ceramic material for artificial bone substitution in biomedical field owing to its chemical and crystallographic similarities of natural bone and teeth. In this research work, we have attempted the synthesis of hydroxyapatite powders with controllable size in the presence of three different surfactants sodium dodecyl sulphate (SDS) which is an anionic surfactant, cetyl trimethylammonium bromide (CTAB) as a cationic surfactant and poly vinyl alcohol (PVA) as a non-ionic surfactant. The as-synthesised HAP powders were characterised by analytical techniques such as FTIR, XRD and SEM. The results have shown that the non-ionic surfactant is a better choice for developing this bio-nanomaterial due to its good dispersing power than CTAB and SDS. The results have also indicated that, nano-hydroxyapatite particle has a uniform morphology, well crystallinity and the particle size was controlled with the use of non-ionic surfactant. The crystallite size was calculated using Scherer’s formula. Experiments were performed under controlled environment by maintaining the required pH, concentration and temperature. The biomedical application studies of the as-synthesised material are yet to be studied.

Borehole tube sampling is a key process of geotechnical engineering. The paper presents numerical analyses of smooth tube sampling in clay using the Particle Finite Element Method (PFEM). The soil is described by a conventional elasto-plastic constitutive model (Tresca plasticity and a quasi-incompressible elastic law). The sampler is advanced by several diameters into the soil until a steady state is observed. The elasto-plastic numerical solution for a round-tipped sampler clearly identifies a localized shear failure mechanism at the entrance of the tube. Relevant Strain Path Method (SPM) solutions are numerically evaluated to facilitate full field comparison. For a given thickness ratio elasto-plastic simulation predicts far less compression but much larger extensions at the centerline than SPM. The results also show how including a beveled sampler tip or a stationary piston changes the failure mechanism and significantly reduces induced peak extension strains. The results agree with available experimental data and well-established empirical observations. The methodology presented may open the way to a soil mechanics based rational approach to soil sampling simulation. This work has been supported by the Ministry of Science and Innovation of Spain through research grant BIA2017-84752-R. The third author acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the "Severo Ochoa Programme for Centres of Excellence in R&D" (CEX2018-000797-S)

Gap graded concrete, also known as pervious concrete, or enhanced concrete, is a storm water drainage replacement. Pervious or porous concrete is a homogeneous mixture of cement, fine aggregates to some percent, coarse aggregate and admixtures with partial substitutes of fine aggregate. The particle sizes and proportions of the materials used indicate the value and permeability of this form of concrete. We addressed the strength parameters and permeability of this concrete with various aggregate sizes in this paper. The 70:30 coarse aggregate mix ratio is used. Two coarse aggregate mixes of 20–10 mm and 10–6 mm were used in this study for the different aggregate ratios. The larger the aggregate, the better the porosity for rainwater runoff and storage. To achieve better performance, 15% fly ash is used as a substitute for cement in the mix design in the experiments. The water binder ratio is kept constant at 0.38, while the cement to aggregate ratio is set at 1:5. The porous concrete moulds are cast and tested for mechanical and toughness properties. For the above-mentioned tests, cubes, tubes, and beams are casted.

Solid-state lithium batteries (SSLBs) have been identified as one kind of the most promising energy conversion and storage devices because of their safety, high energy density, and long cycling life. The development of solid-state electrolyte is vital to commercialize SSLBs. Composite polymer electrolyte (CPE), derived by compositing inorganic particles into solid polymer electrolyte has become the most practical species for SSLBs because it inherits the advantages of polymer electrolyte and simultaneously achieves enhanced ionic conductivity and mechanical properties. The characteristics of inorganic particles and their interaction with polymers strongly impact the performance of CPE, improving its ionic conductivity, mechanical properties, thermal and electrochemical stability, as well as interface compatibility with both electrodes. In this review, the effects of particle characteristics including its species, size, proportion, morphology on the ionic conductivity and mechanical properties of CPE are reviewed. Meanwhile, some novel composite strategies are also introduced including surface modification, hybridization, and alignment of particles in polymer matrices, as well as some new preparation methods of CPE. The interactions between particles and other components in CPE including polymer matrices or lithium salt are particularly focused herein to reveal the lithium conductive mechanism. Finally, a perspective on the direction of future CPE development for SSLBs is presented.

The particle morphology of granular materials comprises different characteristic scales, including particle shape and surface texture. Different methods have been proposed to characterise the morphology using three-dimensional parameters, among which is the fractal method. These methods, however, are applied either at the scale of particle shape or surface texture. A framework unifying the multi-scale morphology obtained from different measuring instruments could advance the current understanding to this topic, but is still lacking. This paper proposes a novel methodology to characterise the morphology of sand particles across different scales based on results from two previously adopted instruments with different measuring capabilities – an X-ray micro-computed tomography (μCT) and a high-resolution optical microscope equipped with an interferometer. The methodology is applied to sand-sized particles of a crushed granitic rock and a natural quarzitic sand (Fujian sand). By using spectrum analysis on data from both μCT and interferometer measurements, a single fractal dimension is found linking the spectrum of the two measurements for the crushed granitic rock. For Fujian sand, two self-affine patterns are observed, which serves as a separation between particle shape and surface texture, and also indicates that the fractal dimension obtained at larger scale may not be simply extended to small scales. The translation of surface measurements into numerically reconstructed particle morphology at particle shape and surface texture scale is demonstrated by using spherical harmonic expansion and power spectral density functions.

Mixing index is an important parameter to understand and assess the mixing state in various mixers including ribbon mixers, the typical food processing devices. Many mixing indices based on either sample variance methods or non-sample variance methods have been proposed and used in the past, however, they were not well compared in the literature to evaluate their accuracy of assessing the final mixing state. In this study, discrete element method (DEM) modelling is used to investigate and compare the accuracy of these mixing indices for mixing of uniform particles in a horizontal cylindrical ribbon mixer. The sample variance methods for mixing indices are first compared both at particle- and macro-scale levels. In addition, non-sample variance methods, namely entropy and non-sampling indices are compared against the results from the sample variance methods. The simulation results indicate that, among the indices considered in this study, Lacey index shows the most accurate results. The Lacey index is regarded to be the most suitable mixing index to evaluate the steady-state mixing state of the ribbon mixer in the real-time (or without stopping the impeller) at both the particle- and macro-scale levels. The study is useful for the selection of a proper mixing index for a specific mixture in a given mixer.

Micrometre-sized electrode materials have distinct advantages for battery applications in terms of energy density, processability, safety and cost. For the silicon monoxide anode that undergoes electrochemical alloying reaction with Li, the Li (de)intercalation by micron-sized active particles usually accompanies with a large volume variation, which pulverizes the particle structure and leads to rapidly faded storage performance. In this work, we proposed to stabilize the electrochemistry vs. Li of the micron-SiOx anode by forming a rigid-flexible bi-layer coating on the particle surface. The coating consists of pyrolysis carbon as the inner layer and polydopamine as the outer layer. While the inner layer guarantees high structural rigidity at particle surface and provides efficient pathway for electron conduction, the outer layer shows high flexibility for maintaining the integrity of micrometre-sized particles against drastic volume variation, and together they facilitate formation of stable solid electrolyte interface on the SiOx particles. A composite anode prepared by mixing the coated micron-SiOx with graphite delivered improved Li storage performance, and promised a high-capacity, long-life LiFePO4/SiOx-graphite pouch cell. Our strategy provides a general and feasible solution for building high-energy rechargeable batteries from micrometre-sized electrode materials with significant volume variation.

To deeply knowledge of the flow behaviors of pulverized coal particles in dense gas–solid two-phase flow, a multi-scale analysis method based on electrostatic sensor array is applied for the multi-scale characterization of flow behaviors of dense gas–solid flow. The experimental results indicate that: for steady flow, with the increment of conveying pressure difference, the individual particles increase and the particle clusters decrease, the individual particle distribution is always inhomogeneous but the particle cluster distribution tends to be more homogeneous over the cross-section of pipe, while the average flow behavior of pulverized coal particles is always in the relatively static state. For unsteady flow, the average flow behavior of pulverized coal particles is dynamic, and the flow behaviors of the multi-scale flow structures over the cross-section of pipe are all significantly inhomogeneous. Moreover, the effect of particle size on flow behavior of pulverized coal is also investigated and validated.

The use of biofuels helps mitigate greenhouse gas emissions. Earlier studies have shown that transporting biomass in horizontal pipelines in the form of water-based slurries significantly reduces transportation costs. The frictional behaviour of water-based chopped wheat straw slurry in a vertical pipeline has not been studied and this is the focus of this study. In situ concentrations of water-based conventional solids of medium sand, glass beads, and fine sand and straw slurry flows were determined by measuring their delivered concentrations in pseudo-homogeneous regimes for prepared concentrations of 1–6% (dry volume of conventional solids) and 5–25% (saturated mass of straw), respectively. Two grades of sand and glass beads with mean particle diameters of 0.103, 0.447, and 0.5 mm, respectively, and straw with a nominal particle length of 19.2 mm were utilised. The delivered concentrations for the straw slurries and fine sand were close to their corresponding prepared concentrations and were homogeneous. There was a large discrepancy between prepared and delivered concentrations for the medium-sized sand and glass beads slurries. The pressure drop of straw slurries over the range of velocities of 0.5–4.2 m s−1 and mass concentrations of 5–25% through the vertical pipe showed a maximum drag reduction of 19% at a concentration of 25% (mass) and at a 3.5 m s−1 velocity. For concentrations of 5–20% (mass), the straw slurries showed drag-reducing capabilities in the mixed and turbulent flow regions for various velocities that were different from horizontal flows.

Particle tracking techniques such as magnetic particle tracking, radioactive particle tracking and positron emission particle tracking are widely used in academia and industry to image the dynamics of particulate and multiphase systems. These techniques can provide detailed data concerning a range of important, whole-field quantities based only on the time-averaged dynamics of a small number of tracer particles. However, in order for this data to be reliable, the duration over which these time-averages are taken must be suitably long. Further, the ‘minimum averaging time’ required to produce good statistics depends sensitively on the system in question and, at present, cannot be determined a priori in advance of an experiment. In this paper, we take a step toward resolving this issue, using discrete element method simulations of a simple vibrofluidised granular bed to develop a series of scaling laws relating said minimum averaging time to a variety of key system variables. The scaling laws developed may be used by future experimentalists to predict the required averaging time for each given system during an experimental campaign, thus improving both the efficiency with which particle tracking techniques may be applied, and the reliability of the data produced thereby.

Several parametric effects on the magnetic collection have been evaluated considering dimension, strength of external magnetic field, injected velocity and particle concentration in the working fluid. Besides, accidental environments, expected in the containment of nuclear power plants, have also been addressed for the capture efficiency. The capture efficiency is especially enhanced with magnetic particle size and magnetic field strength through increased magnetic force; the non-magnetic coating thickness and fluid velocity hinder the magnetic collection. Based on the assessment, the magnetic withdrawal system can effectively capture magnetic particles even under accidental environments. Withdrawal of multifunctional magnetic particles or filtering of magnetic impurities can be effectively realized through the system.

This paper presents the simulation of material flows in the large-scale charging chute of Fos-Sur-Mer sinter cooler plant by using three-dimensional Discrete Element Method (DEM). As a result of granular flows in the chute, segregation patterns are formed at the charging exit. The sinter material is modelled as dry particles and their size distribution in the simulation is larger than in the reality to keep the simulation in a reasonable run time. Suitable calibration tests are performed to specify the DEM contact parameters in order to replicate the behavior observed during experiments with the virtual sinter particles. The DEM model is found to be in good agreement with a segregation measurement. A sensitivity analysis using different particle sizes shows that the segregation patterns are not affected by the different sizes used for fine particles. Furthermore, the filling ratio in the charging system is varied in the model and shows that a high filling ratio leads to less segregation when exiting the charging chute. The DEM model is used to analyze the granular flows in the charging chute, understand the material behavior and optimize the sinter cooling efficiency.

Al-V-B master alloy is promising for refining Al-Si alloys, yet its optimal composition with superior efficacy remains to be explored. In this work, the evolution of refining phases in the Al-10Si/Al-V-B system with different V:B ratios was evaluated by thermodynamic calculations, based on which the Al-V-B refiners with V:B = 1:1 and 5:1 were designed. Refining trails demonstrated that they could significantly reduce the grain size of Al-10Si (wt.%) alloy from 1736 to 184–245 μm with industrial addition amount. Detailed examinations results clarify that when V:B ratio is 1:1 the nucleation particle is (V,Al)B2, which has a VB2-AlB2 core-shell structure and therefore presents the nucleation capability as AlB2 particle. When V:B ratio is as high as 5:1, the nucleation particle is pure VB2. Density functional theory (DFT) calculation indicates that (0 0 0 1) VB2/(1 1 1) α-Al interface has the lowest interfacial energy such that highest nucleation potency among other types of diboride/α-Al interfaces under consideration. The outcomes of this work provide fundamental guidance to develop superior V-B based refiners for Al-Si alloys.

The effects of operating pressure on the gas–solid flow characteristics in a pressurized circulating fluidized bed (CFB) gasification system were studied by experiment and simulation. Elevated operating pressure was found to increase the particle uniformity in the axial and radial directions. Experiments and simulations both showed that as the operating pressure increased, the pressure drops along the riser height decreased. The experimental pressure drops at the same locations decreased when the operating pressure increased, but the opposite trend was observed in the simulation results. A proper drag model must be developed for the accurate simulation of pressurized CFB operation, and the accuracy of electrical capacitance tomography (ECT) measurement and cross-correlation analysis should be improved for better prediction of the particle circulation flux.

Rapid, inexpensive, and laboratory-free diagnostic of viral pathogens is highly critical in controlling viral pandemics. In recent years, nanopore-based sensors have been employed to detect, identify, and classify virus particles. By tracing ionic current containing target molecules across nano-scale pores, nanopore sensors can recognize the target molecules at the single-molecule level. In the case of viruses, they enable discrimination of individual viruses and obtaining important information on the physical and chemical properties of viral particles. Despite classical benchtop virus detection methods, such as amplification techniques (e.g., PCR) or immunological assays (e.g., ELISA), that are mainly laboratory-based, expensive and time-consuming, nanopore-based sensing methods can enable low-cost and real-time point-of-care (PoC) and point-of-need (PoN) monitoring of target viruses. This review discusses the limitations of classical virus detection methods in PoN virus monitoring and then provides a comprehensive overview of nanopore sensing technology and its emerging applications in quantifying virus particles and classifying virus sub-types. Afterward, it discusses the recent progress in the field of nanopore sensing, including integrating nanopore sensors with microfabrication technology, microfluidics and artificial intelligence, which have been demonstrated to be promising in developing the next generation of low-cost and portable biosensors for the sensitive recognition of viruses and emerging pathogens.

Summary During olefin polymerization on supported catalysts, the controlled morphological evolution of the catalyst particle is vital for ensuring optimal product properties and high catalyst activity. We employed non-destructive hard X-ray holotomography to quantitatively assess the 3D morphology of multiple silica-supported hafnocene-based catalyst particles during the early stages of gas-phase ethylene polymerization. Image processing and pore network modeling revealed clear variations in the dimensions and interconnectivity of pristine particles' macropore networks. This, together with apparent differences in the fragmentation behavior of pre-polymerized particles, suggests that the reactivity and morphological evolution of individual particles are largely dictated by their unique support and pore space architectures. By minimizing the structural heterogeneity among pristine catalyst particles, more uniform particle morphologies may be obtained. Significant polymerization activity, observed in the particles' interiors, further implies that appropriate polymerization conditions and catalyst kinetics can guarantee sufficiently high particle accessibilities and thus more homogeneous support fragmentation.

Mie-Gans theory optically characterizes ellipsoidal and by extension generally elongated nonchiral metal nanoparticles (MNPs) and is ubiquitous in verifying experimental results and predicting particle behavior. Recently, elongated chiral MNPs have garnered enthusiasm, but a theory to characterize their chiroptical behavior is lacking in the literature. In this Letter, we present an ab initio model for chiral ellipsoidal MNPs to address this shortcoming and demonstrate that it reduces to the general Mie-Gans model under nonchiral conditions, produces results that concur with state-of-the-art numerical simulations, and can accurately replicate recent experimental measurements. Furthermore, to gain physical insights, we analyze factors such as background medium permittivity and particle size that drive the chiroptical activity using two types of plasmonic chiral MNPs. We also demonstrate the utility of our model in metamaterial design. Generic features of our model can be extended to characterize similar elongated chiral MNPs, fueling many other variants of the current model.

The importance of PEG architecture on nanoparticle (NP) functionality is known but still difficult to investigate, especially at a single particle level. Here, we apply DNA Point Accumulation for Imaging in Nanoscale Topography (DNA-PAINT), a super-resolution microscopy (SRM) technique, to study the surface functionality in poly(lactide-co-glycolide)–poly(ethylene glycol) (PLGA–PEG) NPs with different PEG structures. We demonstrated how the length of the PEG spacer can influence the accessibility of surface chemical functionality, highlighting the importance of SRM techniques to support the rational design of functionalized NPs., The importance of PEG architecture on nanoparticle (NP) functionality is known but still difficult to investigate. Here, DNA-PAINT and qPAINT are used to quantify this phenomenon at a single particle and molecular level.