Particles Of Different Materials Research Articles

Mixed metal differentiation method using microfluidic oil detection sensors

This paper analyzes the characteristics of iron particles and copper particles in the alternating magnetic field with the change of excitation frequency, and proposes a method of using microfluidic oil detection sensor to achieve the distinction of mixed metals. The magnetic field strength of the coil is changed by changing the excitation frequency, which in turn makes the metal particles of different materials act with different strengths in the magnetic field, and realizes the accurate detection of the particles. In the article, firstly, the magnetization effect of the particles in the alternating magnetic field is simulated by the simulation software, the change of the magnetization effect with frequency is simulated, and the change curve of the inductance signal when the particles pass is obtained. Then the experimental verification is carried out by building a test bench, and the experimental results are consistent with the simulation results, which all confirm the feasibility of realizing the detection of aliased particles by frequency conversion. The method provides a new reference direction for the precise and accurate detection of oil detection technology, and has good research value.

DEDALO: Device for Enhanced Dust Analyses with Light Obscuration sensors

Instruments based on light obscuration sensors are widely used for measuring the size distribution of insoluble sub-visible particles in liquid suspensions, being fast and suitable for in situ and real-time measurements. Such instruments are typically calibrated by means of reference polystyrene spherical particles with a specific refractive index, which unavoidably leads to systematic errors when determining the size of particles of different materials. In this paper, we propose a reliable and consistent method to overcome this limitation by setting the refractive index value according to the sample, thus achieving an improved particle size distribution (PSD) measurement. An ad hoc, ready-to-use, open source code with a graphical interface able to drive an in-line instrument and obtain a real-time correction to the PSD has been developed. The method has been extensively validated with several oil emulsions characterized by different refractive index values and the results have been compared with an independent optical method. As an example of application, we have adopted this approach for the analysis of dust suspended in meltwater of an ice core from a glacier in the Aosta Valley (Italy). We believe that our approach will strongly improve the accuracy in characterizing liquid suspensions and reduce discrepancies between data obtained with different methods. The code has been made publicly available at: https://instrumentaloptics.fisica.unimi.it/dedalo/ and on the GitHub page of the corresponding author (https://github.com/LucaTeruzzi/DEDALO).

Experimental Study on Coefficient of Restitution of Small-Sized Spherical Particles during Low-Speed Impact

This study presents experimental investigations on the normal restitution coefficients of a titanium bead (Ti), zirconia bead (ZrO2), and amorphous zirconium alloy sphere (Amor). The research explores the influence of particle diameter and collision velocity on the normal restitution coefficient between two independent, identical spherical particles of different materials. The experimental findings demonstrate that increasing the particle diameter results in more effective plastic deformation, leading to higher energy losses and, subsequently, smaller coefficients of restitution. Similarly, higher particle velocities cause more energy dissipation during collisions, resulting in smaller restitution coefficients. Comparing particles of different materials, those with larger yield strengths exhibit more elastic behavior, experience less initial energy loss due to deformation, and reach the maximum restitution coefficient (elastic state) with fewer collisions. This finding suggests that material properties significantly influence the overall energy dissipation and elastic response in the particles. To validate the experimental results, existing models are compared and discussed. Furthermore, potential physical mechanisms responsible for the observed behavior are explored, providing valuable insights into the collision dynamics in spherical particle interactions. Overall, this study contributes to a better understanding of the factors affecting the normal restitution coefficient in particle collisions, enabling the design and optimization of particle systems for diverse applications in condensed matter and related fields.

Роль коллоидных частиц в воздействии электромагнитных полей и напряжений сдвига на вязкость и фильтрацию нефти и воды

The similarity of the results of exposure to an electromagnetic field, shear stresses, pressure fluctuations, for example, on the viscosity of oil, the rate of growth of paraffin deposits, the rate of growth of Ca/Mg carbonates deposits suggests that such results are the result of the same primary changes in the colloidal components of these systems.Based on the analysis of experimental data, it is shown that the results of such impacts can be explained by the destruction of colloidal aggregates of fractal structure consisting of colloidal particles of different material composition.Due to presence of magnetic and/or electrically charged metal oxides particles in fractal aggregates it make to be possible to split aggregates into separate fragments by applying electromagnetic fields. The particles in suchstructures are interconnected by such weak forces of electric and magnetic origin that the destruction of aggregates occurs even at small values of the fluid velocity gradients corresponding to small values of shear stresses.

Surface modification of particles in a photochemical fluidized bed

Different techniques have been recently studied to promote the surface modification of materials. Surface modifications are used to improve the performance of materials in diverse areas, such as chemical processes, pharmaceutical industry and agriculture. Despite the considerable work in the literature on the subject, the experiments carried out were always conducted with small samples of the materials, and the performance of the treatment on a larger scale has yet to be evaluated. This work aimed to make the surface modification of particles of different materials by UV-assisted treatment in a photochemical fluidized bed. The purpose was to verify the feasibility of treating particles with UV radiation on a larger scale, something not yet found in the literature. The analyzed materials were two polymers and four types of forage seeds. The effect of UV radiation on the surface was checked using the water contact angle (WCA) and FTIR analysis. The treated seeds were also submitted to the Standard Germination Test (SGT) to verify eventual physiological damages and possible beneficial effects of the treatment. The results indicated a significant decrease in the contact angle of the treated particles of all materials because of the incorporation of oxygenated groups on their surface. In turn, the SGT pointed out not only that the seeds were not damaged by radiation but also that there was a significant increase in the agronomic index for two of the species studied. The data obtained in this work showed that the photochemical fluidized bed proved a viable way to carry out the surface treatment of particles with UV radiation, making it possible to conduct the process on a larger scale.

Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics

The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.

Mixing nanoparticles in a ProCell type spouted bed

Mixing nanoparticles is critical in various industries, including pharmaceuticals, solar, and nanotechnology. When different nanopowders are mixed, hetero-aggregates consisting of hetero-contacts are formed, facilitating the exchange of charge, mass and moments between particles of different materials. This research paper presents a novel approach for mixing nanoparticles using special spouted bed equipment to produce hetero-aggregates. The paper explores the potential of special spouted bed equipment for mixing nanoparticles. High-velocity opposed inlet air streams in this equipment result in high gas-solid contact efficiency and enhanced particle circulation, which contribute to the breakage of aggregates and promote the mixing process. The study investigates the aggregate breakage and mixing quality in produced hetero-aggregates. Experimental results demonstrate that the special spouted bed equipment enables efficient mixing of nanoparticles, leading to higher dispersion in hetero-aggregates with many hetero-contacts. The modified homogeneity of mixing method is utilized to quantify the mixing inside the single hetero-aggregates. Visual confirmation of the assessed values of mixing quality is provided by EDX spectral mapping.

Analysis of process parameter sensitivities of jet-based direct mixing gas phase hetero-agglomeration by DEM/CFD-modelling

A new approach to the formation of hetero-agglomerates, originating from mixtures of particles of different materials, has been proposed and analysed. The aim is to develop a process capable of producing hetero-agglomerates with a high relative number of contacts between particles of different materials. The proposed process is a jet based mixing gas phase hetero-agglomeration approach where the particle systems are dispersed into the gas phase and brought together by two particle laden jets. The process is analysed using Discrete Element Method (DEM) one-way coupled with Computational Fluid Dynamics (CFD), including models for adhesive contact forces, turbulence-induced fluctuating fluid forces and Coulomb forces for charged materials. Particle mass flow, particle surface energy, jets relative alignment, gas inflow velocity, particle size and electrical charge are varied to understand their effect on the hetero-agglomerate formation. This allows conclusions to be drawn about process intensification that can be used in subsequent experimental investigations.

Study of the effect of regenerative heat transfer enhancement on the silicothermic reduction process

As the main process for industrialized production of crude magnesium, the silicothermic reduction technology has problems such as high energy consumption per ton of magnesium and serious pollution. Under the policy of carbon peak and carbon neutrality, the implementation of energy conservation and pollution reduction technology reform has become an urgent issue in the silicothermic reduction process. Although the thermal conductivity of the briquettes used for magnesium production is low, they will absorb a lot of heat during the reduction reaction. As a result, the heat cannot be transferred quickly enough for the chemical reaction endothermic, leading to a slow magnesium production reaction and low production efficiency. Therefore, in-depth study on the kinetic mechanism of the improved heat transfer coupled chemical reaction is required to decrease the production cycle and increase efficiency. In this work, the effect of filling the voids of briquettes with regenerative particles of different materials on heat transfer process was first studied by means of experiments. It has been discovered that as the thermal conductivity of the filling material increases, the heat transfer process is accelerated, but the endothermic behavior of the regenerative particles at room temperature during the heating process seriously affects the heat transfer to the briquettes. On this basis, the models of heat transfer and magnesium reduction kinetics were combined and the recycling technology of high temperature regenerative particles with different materials was studied by numerical calculation method. The findings demonstrate that the production cycles for filling aluminum oxide, silicon carbide and silicon nitride are reduced to 6, 4 and 1 h, respectively, at the initial temperature of 1373 K for the regenerative particles, compared with the 8 h of the traditional method. However, when the voids of the briquettes are filled with quartz sand with a thermal conductivity close to that of the briquettes, the period increases to more than 10 h. When the initial temperature of the filled regenerative particles decreases, the production cycle also increases. In industrial production, materials with high thermal conductivity should be selected as regenerative particles as far as possible on the basis of considering the cost, and thermal insulation measures should be taken to minimize the heat loss during the recycling of regenerative particles.

Approaches to Detect Microplastics in Water Using Electrical Impedance Measurements and Support Vector Machines

We propose electrical impedance spectroscopy (EIS) enhanced by machine learning (ML), in particular support vector machines (SVMs), as a noninvasive, in situ method for detecting microplastics in water and as an alternative to slow, expensive laboratory measurements. The primary measurand is the complex-valued electrical impedance of a water-filled measuring cell. We carried out stationary measurements on numerous water samples contaminated with different plastic concentrations in a cylindrical measuring cell and in the frequency range from 20 Hz to 2 MHz. The effects of various influence quantities, such as the concentration of organic material (1.0%, 3.0%, 5.0%) or the salinity of water (0.5%, 1.0%, 3.5%), were also investigated. Measurements at 2 MHz with water flows carrying microplastic particles of different materials and sizes served to investigate the dynamic capabilities of the measurement method. The impedance spectra (stationary measurements) or the measured impedances (dynamic measurements) were then evaluated by specific SVMs. The classification task consisted of distinguishing different plastic materials and particle sizes. In the stationary case, the application of the SVM resulted in assignment accuracies of over 98%. In the dynamic case, the classification accuracies exceeded 91% for the mere classification of particle sizes and 85% for the classification of plastic particles by size and material.

Analysis of the Effect of Velocity on the Eddy Current Effect of Metal Particles of Different Materials in Inductive Bridges.

A method for analyzing the influence of velocity changes on metal signals of different materials in oil detection technology is proposed. The flow rate of metal contaminants in the oil will have a certain impact on the sensitivity of the output particle signal in terms of electromagnetic fields and circuits. The detection velocity is not only related to the sensitivity of the output particle signal, but also to the adaptability of high-speed and high-throughput in oil online monitoring. In this paper, based on a high-sensitivity inductive bridge, the eddy current effect of velocity in a time-harmonic magnetic field is theoretically analyzed and experimentally verified, the phenomenon of particle signal variation with velocity for different materials is analyzed and discussed, and finally the effect of velocity on the output signal of the processing circuit is also elaborated and experimentally verified. Experiments show that under the influence of the time-harmonic magnetic field, the increase of the velocity enhances the detection sensitivity of non-ferromagnetic metal particles and weakens the detection sensitivity of non-ferromagnetic particles. Under the influence of the processing circuit, different velocities will produce different signal gains, which will affect the stability of the signal at different velocities.

WET GRANULATION TECHNOLOGY IN INDUSTRIAL PHARMACY

Abstract. This review discusses wet granulation technology, a process that helps particles of different materials bind to each other, thereby reducing the possibility of separation of materials in subsequent processing steps during their processing and increasing the likelihood of proper dosage uniformity in the dosage form. Granulation is a size-enlarging process in which individual particles of a powder, usually composed of several different components, are combined together to form a larger, structured particle in which the original particles may differ. Granulation makes it possible to change the properties of the solid granular material. Increasing the particle size reduces the potential hazard or harmful effects of the dust. The structure of the granules improves the flowability and compaction of the powder, and also helps to ensure the uniformity of the composition of the powder mass in the case of mixing materials. Wet granulation is a particle size coarsening process widely used in the manufacture of dosage forms. There are several reasons for wet granulation of pharmaceutical mixtures. An increase in particle size leads to an improvement in fluidity. The wet granulation process physically binds the mixed particles, thereby reducing the chance of separation of substances and causing possible dosing uniformity problems. Another reason for granulation is to reduce the possibility of separation of the pharmaceutical substance and/or excipients. Granulation technology always guarantees good flow properties and a uniform bulk density of the powder before compression, which is especially important in pharmaceutical development, and also reduces the risk of delamination by creating multi-component granules with a more uniform composition compared to a powder mixture.

Dealing with density discontinuities in planetary SPH simulations

ABSTRACT Density discontinuities cannot be precisely modelled in standard formulations of smoothed particles hydrodynamics (SPH) because the density field is defined smoothly as a kernel-weighted sum of neighbouring particle masses. This is a problem when performing simulations of giant impacts between proto-planets, for example, because planets typically do have density discontinuities both at their surfaces and at any internal boundaries between different materials. The inappropriate densities in these regions create artificial forces that effectively suppress mixing between particles of different material and, as a consequence, this problem introduces a key unknown systematic error into studies that rely on SPH simulations. In this work, we present a novel, computationally cheap method that deals simultaneously with both of these types of density discontinuity in SPH simulations. We perform standard hydrodynamical tests and several example giant impact simulations, and compare the results with standard SPH. In a simulated Moon-forming impact using 107 particles, the improved treatment at boundaries affects at least 30${{\ \rm per\ cent}}$ of the particles at some point during the simulation.

Design and Development of Particle Friction and Impact Damping for Spur Gear Drive

Gear transmission system plays an important role in many of the mechanical systems. Vibration is the major problem and unavoidable in gear transmission system because high speed and heavy loading condition. High temperature and harsh working condition limits the other vibration absorption methods. Particle friction & impact damping is passive method of vibration absorption. Ordinary particle damping method gives the random movement of particles. In this research holes are provided to the gear and put cylindrical impact particles in particular hole gives the friction and impact effect to absorb the vibration. The mathematical analysis is formulated for the system also run MATLAB program and found out plot for displacement v/s time. DEM simulation carried out using EDEM software which is used to perform simulations at different speed and to analyze the energy dissipation during particle collisions and compared the energy absorbed by the particles of different materials for varying speed.

Physical properties-based microparticle sorting at submicron resolution using a tunable acoustofluidic device

Acoustophoretic manipulation has been drawing great attention in the area of microfluidics-based cell/particle isolation and sorting due to its advantages of high biocompatibility, contactless manipulation and fabrication simplicity. Most label-free microfluidic particle sorting methodologies are solely based on a single physical property for example particle size, density or material composition, which hinder their broad usage in various applications. In this work, we demonstrate a tunable acoustofluidic device for continuous particle separation based on multi-physical properties such as size, density, compressibility and speed of sound. The tunable acoustofluidic system utilizes an elasto-inertial particle focusing technique to align particles into a single line and integrates a slanted interdigitated transducer (SFIT) that generates a tunable travelling surface acoustic wave to separate the particles with improved sorting accuracy and efficiency. The presented acoustofluidic sorting device allows the generation of a variable frequency from 99 MHz to 247 MHz corresponding to the wavelength 40 μm and 16 μm using the SFIT. We have successfully sorted 5.26 μm from 5 μm polystyrene particles at 90 % accuracy with a relative size difference of 5.2 %. Furthermore, a theoretical analysis of acoustic radiation force (ARF) exerted on rigid particles of different materials (i.e., polystyrene, PLGA, PMMA) is presented. Based on the optimal frequencies identified in the theoretical analysis, we have also experimentally demonstrated effective sorting of the three above-mentioned materials of particles with the same particle size.

Analytical proposal for the assessment of the molecular excitation levels contribution to the mean excitation energy: Application to the water molecule

The mean excitation energy 〈I〉 is a fundamental quantity in radiation physics, concerning energy deposition in matter and absorbed dose analytical estimations for charged particles. The stopping of charged particles in different materials strongly depends on this parameter among others. This work intends to contribute with insights for some issues, usually treated not in detail in the theory of stopping power, as the analytic and theoretic assessment of 〈I〉-value for different relevant materials. A methodology is proposed and described aimed at providing the procedure for the 〈I〉 calculation framework, based on the definition of the mean excitation energy using the dielectric response function is analytically integrable if the inelastic cross section parameters are known. Some dielectric models were studied, aimed at calculating the 〈I〉-value for liquid water by theoretical means, reaching the conclusion that a decay at least of the order of ω−2 in frequency (energy) is needed as weak condition of the optical energy-loss function for the integrals to converge. Afterwards, the first four discrete excitation levels and the diffuse bands for water are treated in a fully analytical scheme, and further compared with numerical results, providing the contribution of these levels to 〈I〉, with the aim of testing the proposed analytical model.

Nanoplastic Analysis by Online Coupling of Raman Microscopy and Field-Flow Fractionation Enabled by Optical Tweezers.

Nanoplastic pollution is an emerging environmental concern, but current analytical approaches are facing limitations in this size range. However, the coupling of nanoparticle separation with chemical characterization bears potential to close this gap. Here, we realize the hyphenation of particle separation/characterization (field-flow fractionation (FFF), UV, and multiangle light scattering) with subsequent chemical identification by online Raman microspectroscopy (RM). The problem of low Raman scattering was overcome by trapping particles with 2D optical tweezers. This setup enabled RM to identify particles of different materials (polymers and inorganic) in the size range from 200 nm to 5 μm, with concentrations in the order of 1 mg/L (109 particles L-1). The hyphenation was realized for asymmetric flow FFF and centrifugal FFF, which separate particles on the basis of different properties. This technique shows potential for application in nanoplastic analysis, as well as many other fields of nanomaterial characterization.

Nonconductive Noncharging Composites: Tunable and Stretchable Materials for Adaptive Prevention of Charging by Contact Electrification.

Static charge generated by contact electrification can cause a wide range of undesirable consequences in our lives and in industry (e.g., adhesion of particles on surfaces, damage to electronics, and explosions). It has, however, been challenging to develop methods to prevent charging due to the vast types of materials that charge easily by contact electrification and the frequent changes in process and environmental conditions. The most common method is to use conductive materials for dissipating charge away; however, it is ineffective for many circumstances. Here, we propose a general and effective materials framework that involves a two-level consideration for preparing noncharging materials: (1) the variation of the proportion of a two-material composite and (2) the extent of stretching the composite material. This materials strategy is achieved by infusing particles within a stretchable bulk material. Importantly, the preparation of the noncharging surface for (1) is based on a novel fundamental mechanism that involves combining an appropriate amount of a material (e.g., the particles) that tends to charge positively with another material (e.g., the bulk material) that tends to charge negatively. This mechanism does not rely on conductivity; both the contacting materials naturally prevent the generation of static charge even when only nonconductive materials are involved. When the composite material is stretchable, the change in proportion of the surface coverage of the particles allows the charging response to be changed. Therefore, the variation in composition and stretching provide a wide two-dimensional parameter space for achieving noncharging response for the vast range of contacting materials that are used in industry and our lives. In addition, stretchability allows the composite material to flexibly adapt to changes in process and environmental conditions. This stretchable composite material was also demonstrated to be capable of preventing the adhesion of particles and separating particles of different materials.

High-precision in-situ size measurements of single microparticles in an RF plasma

An in-situ method to measure the radii of single microparticles in plasmas with high precision is presented. The particles are trapped in the plasma sheath and illuminated with laser light. Using out-of-focus imaging and polarizing optics, the angle- and polarization-resolved scattering intensities are measured and compared to Lorenz-Mie theory. A two-stage fit procedure is introduced to obtain the complex refractive index in addition to the particle radius. Complementary long-distance microscopy measurements are performed to compare with fit results. The method is applied to particles of different materials used in complex plasma research to measure etch rates due to plasma inherent processes.

Effect of microshot peened treatment on the fatigue behavior of laser-melted W6Mo5Cr4V2 steel gear

In this paper, W6Mo5Cr4V2 steel gear tooth flank was firstly melted by laser irradiation, and then treated by microshot peening (MSP) with shot particles of different materials and peening time. The materials of shot particles were high-carbon cast steels and ceramics. The peening time was from 20s to 100s. The fatigue behavior of gear was tested using Forschungsstelle für Zahnräder und Getriebebau (FZG) back-to-back spur gear test machine. The experimental results have showed that the microhardness of gears increased, and the surface roughness of gears decreased after microshot peening treatment. In addition, the residual stress state in the near-surface layer of microshot peened gears was changed from tensile stress to compressive stress. The microshot peening treatment has improved the fatigue strength of gears in comparison with gears undergoing the laser surface melted (LSM). The material of microshot particle influenced the fatigue behavior of gears going through laser surface melting and microshot peening (LSMMSP). The fatigue properties of LSMMSP gears did not enhance with an increase in shot peening time. The effects of the relaxation mechanism of the compressive residual stress on the fatigue performance of LSMMSP gears have also been discussed. Retained austenite has played a positive role in improving the fatigue limit of LSMMSP gears.