Behavior Of Particles Research Articles

Size-dependent nonlinear free vibration of magneto-electro-elastic nanobeams by incorporating modified couple stress and nonlocal elasticity theory

Magneto-Electro-Elastic (MEE) Composites, as an innovative functional material blend, are composed of multiple materials, boasting exceptional strength, rigidity, and an extraordinary magneto-electric interaction effect. This paper establishes a nonlocal modified couple stress (NL-MCS) magneto-electro-elastic nanobeam dynamic model. To accurately capture the intricate influences of scale effects on nanostructures, This model meticulously examines scale effects from two distinct perspectives: leveraging nonlocal elasticity theory to elucidate the softening phenomena in nanostructures stemming from long-range particle interactions, and employing modified couple stress theory to reveal the hardening effects attributed to the rotational behavior of particles within the structure. By incorporating Von Karman geometric nonlinearity, Reddy’s third-order shear deformation theory and Maxwell’s equations, the governing equations for the nonlinear free vibration of MEE nanobeams are derived using Hamilton’s principle. Finally, a two-step perturbation method is employed to solve these equations. Two-step perturbation method disintegrates the solution process into two stages, iteratively approximating and refining the solution, thereby progressively unraveling the intricate details and enhancing the precision of the solution in a systematic manner. Finally, the nonlinear free vibration behavior of MEE nanobeams is explored under the coupled magnetic-electric-elastic fields, with a focus on the effects of various factors that including length scale parameters, nonlocal parameters, Winkler-Pasternak coefficients, span-to-thickness ratios, applied voltages and magnetic potentials.

Experimental study on coherent structures by small particles suspended in high aspect-ratio (Γ=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Gamma =$$\\end{document} 2.5) thermocapillary liquid bridges of high Prandtl number

In time-dependent traveling-wave convection, it has been confirmed that small particles of low Stokes number (St≪\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extrm{St}\\ll$$\\end{document} 1) form three-dimensional closed structures known as the particle accumulation structures (PASs). We focus on coherent structures formed in high aspect-ratio thermocapillary liquid bridges (Γ=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Gamma =$$\\end{document} 2.5), where oscillatory convection due to the so-called hydrothermal wave instability of mHTW=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$m_{\ extrm{HTW}}=$$\\end{document} 1 stably emerges, and carry out experimental explorations into the volume ratio dependence of the emergence of coherent structures. Variation in the volume ratio induces the presence of coherent structures with different azimuthal wave numbers, that is, different spatial structures. Among the particles added to the liquid bridge, we perform spatio-temporal tracking of particles to quantify the correlation between the behavior of particles and the spatial structures of coherent structures with different rational wave numbers.

Modified electrode configuration of the free-fall tribo-electrostatic separator for the recovery of polyethylene and polypropylene flakes from shredded packaging waste

Free-fall tribo-electrostatic separators have long been used for sorting granular plastic wastes. The aim of this paper is to propose a modified configuration of the electrode system of such a separator and validate its effectiveness for processing a mixture of polyethylene (PE) and polypropylene (PP) flakes originating from the processing of packaging waste at GRANUPLAST Company, Jassans-Riottier, France. The mixture to be treated is not homogeneous and consisted of roughly 2/3 PE and 1/3 PP. The granular mixture samples were charged by triboelectric effect in a fluidized bed device, and then introduced into a laboratory-scale free-fall electrostatic separator. Preliminary tests were conducted to ascertain the mass of the mixture to be introduced in the fluidized bed and the duration of the charging process. Better results were obtained with the modified electrode configuration of the free-fall electrostatic separator. Thus, from 100 g of mixed flakes, 98.2% of PE and 96.6% of PP were recovered with purities of 99.1% and 98%, respectively. In addition, numerical modeling of the PP and PE particles trajectory was performed to simulate the behavior of charged particles in the standard and modified electrode configurations. Work is in progress for the industrial implementation of this tribo- electrostatic separation technology.

Optimized structure design for binary particle mixing in rotating drums using a combined DEM and gaussian process-based model

Particle mixing is a crucial operation in various industrial production processes. However, phenomena like segregation or local accumulation can arise, especially when particles differ in properties like radius and density. Numerical simulation of particles using Discrete Element Method (DEM) allows for the manipulation of control variables in batches, generating a large amount of data and facilitating quantitative research. In this study, the mixing behaviors of binary particles in rotating drums are systematically investigated. The DEM model is first validated with experimental data and then rotating drums with varying obstacles, rotation speeds, particle radii, and densities are simulated. Moreover, a Gaussian process-based optimization is conducted by correlating Lacey mixing index (MI) and parameterized shape of obstacle to find the optimized mixing condition. Experimental validations are further performed on the optimized condition to verify the design. It is shown that this integrated approach holds significant potential for enhancing the efficiency, effectiveness of industrial mixing processes and the consideration of energy consumption when balancing the mixing efficiency and optimal rotating speed.

Three-dimensional particle-scale investigation of transient gas–solid flow characteristics in the propulsion system with a complex charge structure

This work is focused on researching the particle behavior of the transient gas–solid flow in the propulsion system with the modular charge structure, which has a great effect on the temporal-spatial distribution of energy release. Based on the coupling method of computational fluid dynamics and the discrete element method, an efficient three-dimensional unsteady gas–solid model is developed to provide a detailed means of capturing particle behavior in the propulsion system with a complex structure. Comparisons of the particle distribution of simulation results are done with experimental research, and a reasonable match has been obtained. Furthermore, the particle behavior characteristics can be divided into three stages. In the first stage, the particle behavior is dominated by the high-pressure, high-speed gas from the igniter. In the other two stages, the particle behavior is dominated by the complex gas flow generated by the opening of the module and the groove structure of the vehicle. The results show that the distribution of particles consists of slope accumulation and horizontal accumulation. The slope accumulation with a large gradient contains 84% of the total particles, and the height of the slope accumulation is increased exponentially along the axis.

Growth behavior of heavy metal sulfide particles: A comparison between gas-liquid and liquid-liquid sulfidation

Sulfide precipitation is an effective method for treating acidic heavy metal wastewater. However, the process often generates tiny particles with poor settling performance. The factors and mechanisms influencing particle size and settling performance remain unclear. In this study, the growth behavior of CuS particles generated by two sulfide precipitation methods, gas-liquid and liquid-liquid sulfidation, was investigated. The effects of acidity, sulfur-to-copper molar ratio, and temperature on particle size were analyzed. The results showed that increasing the temperature had an adverse effect on CuS particle growth. Additionally, we found that acidity and sulfur-to-copper molar ratio had a more significant impact on particle growth in the liquid-liquid sulfidation system than in the gas-liquid sulfidation system. Based on supersaturation calculations and XPS analysis, it is found that particle growth in gas-liquid sulfidation systems is mainly influenced by supersaturation, while particle growth in liquid-liquid sulfidation systems is mainly affected by surface charge. This study provides valuable insights into the factors that influence particle growth in sulfide precipitation and can inform the development of strategies to improve the effective precipitation of sulfide nanoparticles in acidic wastewater.

Oxidation behavior of FeV2O4 and FeCr2O4 particles in the air: Nonisothermal kinetic and reaction mechanism

Oxidation behavior of FeV2O4 and FeCr2O4 particles in the air: Nonisothermal kinetic and reaction mechanism

Lattice Boltzmann simulation on particle suspensions containing porous particles in a narrow channel

The suspension of porous particles in fluids occurs widely in various natural and industrial processes. However, the sedimentation behavior of porous particles is not extensively understood as the solid impermeable counterparts. In this work, the drafting–kissing–tumbling (DKT) phenomenon in a narrow channel containing porous particles is investigated by the multi-relaxation-time (MRT) lattice Boltzmann method (LBM). The initial particle spacing Lp* (1.5∼6) and Darcy number Da (8×10−6∼6×10−2) are examined on the sedimentation process of two particles under three initial arrangements, i.e., the trailing particle is porous (case 1), the leading particle is porous (case 2), and both the particles are porous (case 3). The results show that the presence of porous particles can enhance the interactions between two particles, and increasing the penetrability reduces the particle drag force to accelerate sedimentation. The drafting time is insensitive to Da at small Lp*, and it decreases with Da at large Lp* in cases 1 and 3 while it changes to increase with Da in case 2. A phase diagram with respect to Da and Lp* is further extracted to identify three sedimentation modes of particle pairs. It is found that the transition between the one-off DKT and repeated DKT modes is not affected by Lp* in cases 2 and 3, while the critical condition for the non-DKT and one-off DKT modes depends strongly on Da and Lp* in case 2.

Characterization of plasma parameters and neutral particles in microwave and radio frequency discharges in the Toroidal Magnetized System.

A characterization of plasma parameters and neutral particle energies and fluxes has been performed for radio frequency and microwave discharges in the Toroidal Magnetized System (TOMAS). A movable triple Langmuir probe was used to study the electron densities and temperatures, and a time-of-flight neutral particle analyzer was used to measure the energy and fluxes of neutral particles, as a function of the total injected power and the antenna frequency used to generate the plasma. The experimental results can provide information on the behavior of neutral particles at low energies in wall conditioning plasmas.

Metal Particle Behavior Between Dielectric-Coated Electrodes Under DC Voltage

Metal Particle Behavior Between Dielectric-Coated Electrodes Under DC Voltage

Particle behaviors of Imipenem/Cilastatin in various liquids investigated by chemical structures and temporal microscope observations

Imipenem/Cilastatin (IPM/CS) is currently used as an embolic agent in transarterial embolization for chronic musculoskeletal pain due to its efficacy of short-term blood flow occlusion. However, due to its off-label use, the development of new materials to substitute IPM/CS is needed. Therefore, investigating the behavior of IPM/CS particles becomes crucial. In this paper, we observed the changes in particle size of IPM/CS when dissolved in phosphate-buffered saline, normal saline, iodinated contrast agent and water. The results indicated that the particle size of IPM/CS ranged from 16 to 57 µm and has fastest hydrolysis rate in iodinated contrast agent. And we analyzed the possible structure of hydrolyzed product of IPM/CS in water at room temperature and 37 ℃ using 1HNMR, HPLC. The results suggested Cilastatin is stable at both temperatures, while Imipenem hydrolyzed to produce slightly different products at different temperatures.

Simultaneous flow and particle measurements for multiphase flows in hydraulic engineering: A review and synthesis of current state

While multiphase flows are abundant in both natural environments and engineering applications, their analysis and quantification present challenges. In particular, simultaneously measuring the flow field and quantifying particle behavior pose many challenges. Methods based on Particle Image Velocimetry (PIV) and Particle Tracking Velocimetry (PTV) principles have been used in the last two decades to measure flow fields and dispersed (particle) phases, respectively. Despite the extensive application of these principles to multiphase flow, there are numerous approaches and techniques used to synchronize and combine PIV and PTV measurements. Combined PIV and PTV data acquisition also requires consideration of phase discrimination to obtain distinct data for the fluid and dispersed phases. In the literature, various methods have been proposed and applied to achieve phase discrimination. This review paper aims to consolidate and classify various phase discrimination techniques used in specialized applications in hydraulic engineering. These methods are categorized into optical (spectral, temporal, and hybrid) and post-processing methods, with a particular emphasis on their applicability within the realm of hydraulic engineering. Moreover, this review expands on several emerging PIV/PTV technologies and applications, where the combination of equipment and algorithms has led to significant strides in the non-intrusive measurement of multiphase flow. By consolidating and critically evaluating current methods for particle discrimination, this paper aims to enhance the scientific community's understanding of simultaneous phase velocity measurements, thereby setting the stage for advancements in multiphase flow visualization techniques.

Assessment of Zitterbewegung Interpretation for Free Particle Solution Using the Concept of Relativistic Wave

The Assessment of the interpretation of Zitterbewegung for free particle solution using various models has been carried out in this work where we firstly considered by using the free particle solution for which Dirac equation and projection operator were carried out.. ln this case, it was invariably revealed that the solution have two doubly degenerate eigenvalues representing positive and negative state that was further support by the analysis which was carried out using Heisenberg’s equation and the representation in relativistic velocity and semi-classical equation of motion for acceleration., but in this second case, the results obtained were observed to have two terms, first terms standing in for rapidly oscillatory motion and the second term representing average motion of the particle in x-direction. The first term in the expression is the one deemed to signify zitterbewegung which is one considered to be sas a result of the fluctuation resulting from the interference between negative and positive energy state while the other term is the normal state terms signifying the average motion of the particle. This therefore confirms the explicit nature of using Dirac equation in handling problems involving the behavior of free particles in field as compared to the use of semiclassical equation of motion.

Probing elastic anisotropy on entropic interfaces

Liquid-liquid phase separation is vital in the formation of many biomolecular condensates, including cellular membraneless organelles. When semiflexible macromolecules are involved, the process switches from mostly enthalpy- to dominantly entropy-driven, changing the intrinsic nature of the interfaces and bringing new physical traits. Here, we present a concept to address the complexity of entropic interfaces where laser trapping and microscopy are combined to capture the behavior of probe colloidal particles onto liquid crystalline droplet surfaces. Hertz-Frank-Oseen contact theory is extended to calculate the elasticity of the droplet based on particle trajectories. We show that this method is sensitive enough to resolve the anisotropic elasticity originating from the collective molecular orientation of constitutive semiflexible mesogens, introducing a possible tool to assess biomechanics of cellular and molecular condensates. Published by the American Physical Society 2024

Influence of in-flight thermal dynamics of metal powder on directed energy deposition process

During the laser directed energy deposition (LDED) process, the in-flight thermal dynamics of metal powders lead to the formation of detrimental by-products such as fumes, flames, and metal vapors. In this work, we use a high-speed camera to investigate the nuanced thermal stage changes of the powders, examining how gas flow rates and laser beam powers influence them. We identify distinct stages in the powder's journey: heating up, fusion and vaporization, flaming, tailing, and accelerated falling. Notably, the latter stages adversely affect both the processing environment and surface quality. Control over gas flow rate and laser beam power dictates the trajectory, duration, and intensity of tailing. Additionally, laser irradiation accelerates the falling speed of particles by 6.8–22.8% compared to non-irradiated ones. Higher laser beam powers increase vaporization-induced propulsion, culminating in escalated particle velocities. Optimal gas flow rates enhance the surface quality by significantly minimizing high-temperature spatter. Through this work, the in-flight thermal dynamic behaviors of metal particles and their impact on LDED processing are explained.

CFD-DEM modelling of particle entrainment in wheel–rail interface: a parametric study on train characteristics

Rail-sanding is employed to improve the train’s wheel–rail traction loss in low adhesion conditions. This can significantly impede trains’ kinematics, operation, and performance by hindering the train’s acceleration and deceleration, resulting in delays and unreliability of transport system as well as causing safety risks and in the worst cases train collisions. Rail-sanding has its own merits in recovering the wheel–rail traction but can result in a sand wastage of more than 80% due to its low sand entrainment efficiency. In this research, computational fluid dynamics is coupled to discrete element modelling to study the behaviour of sand particles during rail-sanding. A parametric study based on the train characteristics, including train velocity, sand flow rate, and the geometry of the sander nozzle, is performed by comparing the entrainment efficiency of the sand particles. It is found that train velocities over 30 m/s result in the entrainment efficiency of almost zero. A moving air layer generated at the wheel–rail interface influences the lower bound of acceptable particle size range. The flow rate and nozzle geometry can be designed to enhance entrainment efficiency.

Modeling and analysis of surface integrity transition in cutting of Sip/Al composites based on coordination deformation effect of particle-matrix

With the wide application of Sip/Al composites in key fields, it is critical to understand the material removal behavior and surface integrity evolution mechanism of Sip/Al composites. In this paper, based on the nanoindentation and scratching experiments, the coordination deformation behavior of Si particles and the Al matrix were investigated at the micro-scale, and the mechanism and conditions of surface integrity transition (SIT) of Sip/Al composites were elucidated. Then, taking into account the feature of particle fragmentation and detachment caused by interfacial failure, an analytical model of specific cutting energy for Sip/Al composites cutting under different material removal modes was established. The competitive relationship between ductile deformation and surface defect formation was investigated, and a quantitative prediction model for the critical depth of SIT was proposed. The results show that the evolution of the material removal behavior of Sip/Al composites is a consequence of the coordination deformation the Al matrix and Si particles. The material removal mode of Sip/Al composites transitions from ductile removal to quasi-brittle removal with particle fragmentation and detachment, and there is an obvious SIT characteristic. The prediction results of critical depth are in agreement with the experimental results, with an average error of less than 9.8 %. Moreover, an appropriate increase in cutting speed can effectively enhance the surface integrity of Sip/Al composites. This research contributes to a deeper understanding of the low-damage machining mechanism of Sip/Al composites.

The Crushing Distribution Morphology of a Single Particle Subjected to Rotary Impact.

In a vertical shaft impact crusher, the particle crushing process is extraordinarily complex, and the particle shape significantly influences the size distribution of the crushed product. To quantify the crushing behavior of particles more accurately and thus reveal the crushing mechanism of the crusher, an analytical approach is suggested for characterizing the crushing distribution of particles subjected to rotational impact. First, according to the working principle of vertical shaft impact crusher, a rotary impact tester was designed, and the cumulative damage model of particles under repetitive impact was established based on the theory of fracture mechanics, based on which the simulation model of single-particle rotary impact tester was constructed. Then, seven distinct particle shapes were established based on the particle shapes observed during the crusher's actual production. Finally, an investigation was conducted using the simulation model to examine the impact of various rotor velocities and particle shapes on the macroscopic mechanical properties and crushing distribution attributes of single-particle crushing. In the single-particle rotary impact crushing experiments, the findings indicated that the particle crushing transpired at the site of contact with the anvil. The particle size distribution of subparticles generated through the crushing with distinct particle shapes all exhibit single-peak characteristics as rotor speed increases. The magnitude of the peak value progressively escalates in tandem with the rotor speed increase. Furthermore, as the rotor speed increases, so do the cumulative mass distribution and the maximum continuous crushing cumulative mass. When the horizontal aspect ratio of the particles is V < 1 and V > 1, the crushing effect of the particles is poor at the same rotational speed; the curve of the maximum continuous crushing degree has an inverted "V″ shape. The crushing effect of the particles improves as their edges become progressively sharper, and the maximum continuous crushing degree of the particles increases as the edge sharpness of the particles advances.

Numerical modeling of the crushing characteristics of single ore particle based on breakable Voronoi block model

The study of crushing characteristics of irregular single ore particles is considered crucial for understanding the secondary fragmentation mechanism, predicting particle gradation, and optimizing the gravity flow of ore particles. This study introduces a numerical simulation approach for single particle compression crushing utilizing the Breakable Voronoi block model (BVBM). The paper examines the influence of various parameters including ball diameter, loading speed, softening tensile strength factor, softening factor, and BVBM size on the crushing behavior of ore particles. It provides a suggested value range for each meso-parameter suitable for single particle modeling and crushing characteristics research. Additionally, the paper describes the evolution of BVBM crushing mode, the total number of cracks, and the number of contact bonds under the influence of different softening factors. Soft rock particles with high softening factors exhibit more significant softening behavior and ductility compared to hard rock particles with low softening factors.

Research Progress on Numerical Simulation of the Deposition and Deformation Behavior of Cold Spray Particles

It is of significant theoretical and practical value to study the deposition process and deformation behavior of cold-sprayed particles to find the deposition mechanism of cold-sprayed coatings, further improve the coating performance, and expand its application scope. However, observing the deposition process and particle behavior through experiments is difficult due to the brief deposition duration of cold spray particles. Numerical simulation offers a means to slow the deposition process and predict the critical velocity, deformation behavior, bonding mechanism, and residual stress of cold-sprayed particles. This paper uses finite element analysis software, including ANSYS LS Dynamic-2022 R1 and ABAQUS-6.14, alongside various prevalent finite element methods for numerically simulating cold spray particle deposition. These methods involve the Lagrange, Euler, arbitrary Lagrange-Euler (ALE), and Smoothed Particle Hydrodynamics (SPH) to investigate the cold spray particle deposition process. The recent literature primarily summarizes the simulation outcomes achieved by applying these methodologies for simulating the deposition process and deformation characteristics of different particles under varying cold spraying conditions. In addition, the reliability of these simulation results is analyzed by comparing the consistency between the simulation results of single-particle and multi-particle and the actual experimental results. On this basis, these methods’ advantages, disadvantages, and applicability are comprehensively analyzed, and the future simulation research work of particle deposition process and deformation behavior of cold spraying prospects is discussed. Future research is expected to provide a more in-depth study of the micro-mechanisms, such as the evolution of the inter-particle and internal organization of the particles, near the actual situation.