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Journal articles on the topic 'Describing particles'

Author: Grafiati

Published: 30 May 2022

Last updated: 31 May 2022

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1

GONON, P., J. N. FOULC, and P. ATTEN. "A CONDUCTION MODEL DESCRIBING PARTICLE-PARTICLE INTERACTION IN THE CASE OF SURFACE CONDUCTING PARTICLES." International Journal of Modern Physics B 15, no. 06n07 (March 20, 2001): 704–13. http://dx.doi.org/10.1142/s0217979201005180.

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We propose an analytical conduction model describing particle-particle interactions for the case of electrorheological fluids based on surface conducting particles. The system consisting of two contacting spheres immersed in a dielectric liquid is modeled by a distributed impedances network, from which we derive analytical expressions for the potential at the spheres surface, for the electric field in the liquid phase, and finally for the interaction force. The theoretical interaction force is compared with experimental results obtained on insulating spheres coated with a thin conducting polyaniline film. A good agreement is found between the theory and experiment.

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2

Djebara, Abdelhakim, Riad Khettabi, Jules Kouam, and Victor Songmene. "Comparison of the Capability of Peak Function in Describing Real Condensation Particle Counter Profiles." Advanced Materials Research 227 (April 2011): 96–100. http://dx.doi.org/10.4028/www.scientific.net/amr.227.96.

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Accurate measurement of the aerosols concentration is important in many applications of aerosol science. Here we compare the adequacy of a peak function with the profiles distribution given by a particle counter (CPC) classified in the size range 5 to 500 nm, issued in a machine shop. The particle counter uses a laser source and an optical system for the detection of particles. Our experiments lead to some underestimation of the profile. This underestimation corresponds with the parasitic phenomena of air bubbles and water droplets which are recorded by default as particles. The results of this study underscore the compatibility of a function Gaussian modified by exponential with the distribution profile given by the particle counter (99%).

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3

Yang, Zon-Yee, and Shin-Chen Lo. "Describing the geometrical packing of gravelly cobble deposits using pair-correlation functions." Canadian Geotechnical Journal 38, no. 6 (December 1, 2001): 1343–53. http://dx.doi.org/10.1139/t01-065.

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There is a close correlation between the mechanical behavior of gravelly cobbles and their geometrical fabric. In geotechnical engineering, the particle-size distribution curve is used to describe the particle gradation. However, a group of particles with the same particle-size distribution can result in several packing arrangements due to the different sedimentation processes. The particle-size distribution curve does not distinguish this characteristic. This study attempts to employ the pair-correlation function of point field theory for describing the geometric packing of gravelly cobble deposits. In the point field, a single gravel- or cobble-sized particle is represented by a point of its geometric center. The pair-correlation function can statistically illustrate the characteristics of a geometrical point pattern and is helpful in interpreting the neighborhood relationship between particles, such as the frequency of interpoint distances and the dominant particle sizes in a point process. Some examples based on ideal particle shapes and arrangements are analyzed to illustrate the interpretations from the pair-correlation functions. The characteristics of pair-correlation functions of field examples are also explained. It is shown that the pair-correlation function can provide another approach to understanding the geometrical packing characteristics of a gravelly cobble formation.Key words: gravelly cobble deposit, geometrical packing, interpoint distance, particle-size distribution, pair-correlation function, point field theory.

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4

Zinoun, A., and J. Cortois. "Pertinent statistics for describing a system of particles." Journal of Mathematical Physics 32, no. 1 (January 1991): 247–49. http://dx.doi.org/10.1063/1.529125.

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5

FILIPPOV, A. T. "A GAUGE MODEL DESCRIBING N RELATIVISTIC PARTICLES BOUND BY LINEAR FORCES." Modern Physics Letters A 04, no. 05 (March 10, 1989): 463–73. http://dx.doi.org/10.1142/s0217732389000563.

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A relativistic model of N particles bound by linear forces is obtained by applying the gauging procedure to the linear canonical symmetries of a simple (rudimentary) nonrelativistic N-particle Lagrangian extended to relativistic phase space. The new (gauged) Lagrangian is formally Poincaré invariant, the Hamiltonian is a linear combination of firstclass constraints which are closed with respect to Poisson brackets and generate the localized canonical symmetries. The "gauge potentials" appear as the Lagrange multipliers of the constraints. Gauge fixing and quantization of the model are also briefly discussed.

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CALZADO, L., H. YEPEZ-MARTINEZ, and H. A. CALDERON. "MODELING THE MICROMECHANICAL STATE OF γ′-PRECIPITATES IN Ni-BASED SUPERALLOYS." International Journal of Modern Physics B 21, no. 21 (August 20, 2007): 3733–44. http://dx.doi.org/10.1142/s0217979207037612.

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A simple model for describing the mechanical state associated with γ′-particles in Ni – Al superalloys is presented. The model is based on the properties of the anisotropic elastic Green function. The strain and stress fields produced by a single cubic particle are described. The self-energy for parallelepiped γ′-particles is calculated, finding the cubic geometry as the energetically most favorable particle shape. The anisotropy interaction between γ′-particles is investigated. The computed results are further examined considering the interaction energy between constituting elements of the particles. The configurational force acting on a γ′-particle during a creep test is analyzed.

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7

Kisiel, Anna. "How to analyze contextuality of metatextual language units? Notes on the relation: TRS – particle semantics." Cognitive Studies | Études cognitives, no. 11 (November 24, 2015): 293–306. http://dx.doi.org/10.11649/cs.2011.018.

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How to analyze contextuality of metatextual language units? Notes on the relation: TRS – particle semanticsThe presented article is devoted to further (after Kisiel 2010) discussion about contextuality of metatextual language units, especially particles. Having selected contextual particles as an example, the author shows how specific structuralisation of TRS is strictly connected with particle meaning. The observation leads to the conclusion that examination of TRS cannot be avoided when analysing particles. Untangling particles meaning has to be based on describing the TRS they work on. Such a procedure has been only recently applied to Polish lexicography.

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8

YANOVSKY, YU G., V. E. ZGAEVSKII, Z. P. SHULMAN, and E. V. KOROBKO. "ER-FLUID RHEOLOGICAL PROPERTIES IN TERMS OF THE MULTIPARTICLE MODEL OF A COMPOSITE." International Journal of Modern Physics B 16, no. 17n18 (July 20, 2002): 2676–82. http://dx.doi.org/10.1142/s0217979202012839.

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The three-dimensional multi-particle well-ordered model could be considered as an analogy to a crystal body. We use this model for describing rheological properties of concentrated electrorheological fluids (ER fluids). According to this model, the particles of the suspension take their places at sites of a grid with specified type of symmetry and then an electric field is applied to the fluid. Taking into account hydrodynamic couple interaction of particles and forces of electrostatic interaction of particles polarized under the action of an external electric field and employing the mathematical apparatus of the microscopic theory of crystals, we construct the basic relationships for describing viscoelastic electrorheological properties of ER fluids.

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9

LOUIS-MARTINEZ, DOMINGO J. "A DERIVATION OF THE BREIT EQUATION FROM BARUT'S COVARIANT FORMULATION OF ELECTRODYNAMICS IN TERMS OF DIRECT INTERACTIONS." Modern Physics Letters A 27, no. 11 (April 10, 2012): 1250064. http://dx.doi.org/10.1142/s0217732312500642.

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We study Barut's covariant equations describing the electromagnetic interactions between N spin-1/2 particles. In the covariant formulation each particle is described by a Dirac spinor. It is assumed that the interactions between the particles are not mediated by a bosonic field (direct interactions). Within this formulation, using the Lagrangian formalism, we derive the approximate (semirelativistic) Breit equation for two interacting spin-1/2 particles.

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BARRETT, BRUCE R. "JUSTIFICATION OF EFFECTIVE PARTICLE NUMBERS FOR DESCRIBING INTRUDER BANDS." Modern Physics Letters A 07, no. 16 (May 30, 1992): 1391–98. http://dx.doi.org/10.1142/s0217732392001063.

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The standard theoretical explanation of low-lying, deformed, intruder bands in even-even nuclei near closed shells is in terms of two-particle, two-hole excitations across the major-shell gap. One normally ignores the difference between particles and holes and assumes that the effective proton (or neutron) number has increased by four. We provide a justification of this approximation by comparing two F-spin multiplets having the same F value, where one multiplet is for the ground-band levels of a set of nuclei, while the second multiplet is for the intruder-band levels of another set of nuclei.

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11

Schneider, Rolf. "On the mean normal measures of a particle process." Advances in Applied Probability 33, no. 1 (March 2001): 25–38. http://dx.doi.org/10.1017/s0001867800010612.

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The (unoriented or oriented) mean normal measure of a stationary process of convex particles carries information on the mean shape of the particles and may, in particular, be useful for describing and detecting anisotropy of the particle process. This paper investigates the mean normal measure under the aspect of its determination from intersections, especially with lines or hyperplanes.

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12

Shekhovtsov, V. V. "Simulation of the evolution of agglomerated SiO₂ particles in thermal plasma flow." Journal of Physics: Conference Series 2064, no. 1 (November 1, 2021): 012088. http://dx.doi.org/10.1088/1742-6596/2064/1/012088.

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Abstract The paper studies the behavior of agglomerated SiO2 particles in thermal plasma processing. The main stages are determined for their transformation to the hollow melt droplets. The proposed model, which includes partial encapsulation of gas, allows describing and analyzing the evolution stages for the particle size and the shell thickness in the ranges of 50-150 μm agglomerated particles and their 0.2-0.6 porosity.

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13

Luo, Lisha, Zhifu Shen, Xudong Wang, and Hongmei Gao. "Evolution of rattling particles in deviatoric shear deformation of granular material." EPJ Web of Conferences 249 (2021): 11017. http://dx.doi.org/10.1051/epjconf/202124911017.

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Granular material such as clean sand in geotechnical engineering is characterized by structured internal deformation pattern and some interesting particle arrangement patterns. This study focuses on the evolution of the fraction of rattling particles in deviator deformation until the critical state. Numerical simulations using the discrete element method reveal the presence of rattling particles (with zero or only one contact with neighbouring particles) even in a very dense packing system. The results show that the initial fraction of rattling particles depends on sample density and particle size distribution. With the increase of deviator strain, the number and volume fractions of rattling particles gradually approach a steady critical state from either a loose or a dense starting point. An effective void ratio, which is calculated by treating rattling particles as voids, can be viewed as new state parameter describing the effective packing density of sands. Besides, the rattling behaviour strongly depends on particle size distribution.

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14

Alpeissov, Yessenbay, Ruslan Iskakov, Sultanbek Issenov, and Аru Ukenova. "Obtaining a formula describing the interaction of fine particles with an expanding gas flow in a fluid layer." Eastern-European Journal of Enterprise Technologies 2, no. 1 (116) (April 28, 2022): 87–97. http://dx.doi.org/10.15587/1729-4061.2022.255258.

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The interaction of fine particles with an expanding gas flow under fluidization conditions is considered. The objects of study are finely dispersed materials, their single particles, gas flow in a fluidized layer. The study used the laws of dynamics and hydrodynamics, the classical laws of mechanics, as well as mathematical methods for the analytical solution of equations. It is emphasized that when a particle moves upwards in a gas jet, three forces act on it: the resistance force Fc, the gravity force P, and the Archimedes force A. As a result, the motion of a fine particle in an expanding gas flow is described taking into account the law of dynamics. During the study, an analytical equation was obtained to determine the velocity of a particle during its rise and fall in a gas jet. During the study, an analytical equation was obtained to find the height of the particle ascent depending on the gas flow rate for given geometric parameters of the gas flow. The obtained formulas can be used in the process of studying the process of convective drying of finely dispersed materials for various design parameters of the dryer. In practice, as a rule, there are various empirical formulas that describe such interactions of particles for specific parameters, which make it difficult to generalize them. In this work, the correctness of the assumed conditions necessary for the analytical solution of the differential equation of particle motion is proved. As a result, formulas were obtained that make it possible to determine the velocity of a particle in a gas jet and the height of its rise depending on the gas flow rate. On the basis of these formulas, graphic dependences of the gas velocity in the jet on the height Vg=f(Z), as well as the dependences of the height of the particle rise hm on the air flow rate in the jet L at different jet expansion angles α=15°; α=20°; α=30° are plotted. It was found that with an increase in the height Z in an expanding jet, the gas velocity in the jet Vg decreases, with an increase in the air flow rate in the jet L, the height of the particle rise hm increases. These formulas are the basis for further consideration of the movement of particles in a fluidized layer in the process of convective drying of fine materials for its intensification of the drying process

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15

FEDORUK, SERGEY, ANDRZEJ FRYDRYSZAK, JERZY LUKIERSKI, and CÈSAR MIQUEL-ESPANYA. "EXTENSION OF THE SHIRAFUJI MODEL FOR MASSIVE PARTICLES WITH SPIN." International Journal of Modern Physics A 21, no. 19n20 (August 10, 2006): 4137–60. http://dx.doi.org/10.1142/s0217751x06031703.

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We extend the Shirafuji model for massless particles with primary space–time coordinates and composite four-momenta to a model for massive particles with spin and electric charge. The primary variables in the model are the space–time four-vector, four scalars describing spin and charge degrees of freedom as well as a pair of Weyl spinors. The geometric description proposed in this paper provides an intermediate step between the free purely twistorial model in two-twistor space in which both space–time and four-momenta vectors are composite, and the standard particle model, where both space–time and four-momenta vectors are elementary. We quantize the model and find explicitly the first-quantized wave functions describing relativistic particles with mass, spin and electric charge. The space–time coordinates in the model are not commutative; this leads to a wave function that depends only on one covariant projection of the space–time four-vector (covariantized time coordinate) defining plane wave solutions.

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16

Fan, Fa-Gung, and Goodarz Ahmadi. "Dispersion of Ellipsoidal Particles in an Isotropic Pseudo-Turbulent Flow Field." Journal of Fluids Engineering 117, no. 1 (March 1, 1995): 154–61. http://dx.doi.org/10.1115/1.2816805.

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Dispersion of ellipsoidal particles in a simulated isotropic pseudo-turbulent field is studied. A procedure using Euler’s four parameters in describing the particle orientations is used, and the governing equations for the translational and rotational motions of particles are outlined. Turbulence fluctuation velocity field is simulated by a Gaussian random model. Motions of ellipsoidal particles of different sizes and lengths are analyzed. Ensemble and time averagings are used for evaluating various statistics of particle motion. Effects of size, shape, and density ratio on the mean-square particle velocities and the relative particle diffusivities are studied. By applying the orientation-averaging procedure, an analytical model for estimating the mean-square particle velocities and the relative diffusivities is developed. The predictions of the approximate model are compared with the simulation results and discussed.

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17

FINKELSTEIN, R. J. "QUANTUM GROUPS AND FIELD THEORY." Modern Physics Letters A 15, no. 28 (September 14, 2000): 1709–15. http://dx.doi.org/10.1142/s0217732300002218.

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When the symmetry of a physical theory describing a finite system is deformed by replacing its Lie group by the corresponding quantum group, the operators and state function will lie in a new algebra describing new degrees of freedom. If the symmetry of a field theory is deformed in this way, the enlarged state space will again describe additional degrees of freedom, and the energy levels will acquire fine structure. The massive particles will have a stringlike spectrum lifting the degeneracy of the point-particle theory, and the resulting theory will have a nonlocal description. Theories of this kind naturally contain two sectors with one sector lying close to the standard theory while the second sector describes particles that should be more difficult to observe.

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18

Ivanov, Alexander A., Dmitri V. Alexandrov, and Irina V. Alexandrova. "Dissolution of polydisperse ensembles of crystals in channels with a forced flow." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, no. 2171 (April 13, 2020): 20190246. http://dx.doi.org/10.1098/rsta.2019.0246.

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A non-stationary integro-differential model describing the dissolution of polydisperse ensembles of crystals in channels filled with flowing liquid is analysed. The particle-size distribution function, the particle flux through an arbitrary cross-section of the channel, the particle concentration profile, as well as the disappearance intensity of particles are found analytically. It is shown that a nonlinear behaviour of solutions is completely defined by the source term of particles introduced into the channel. In particular, the model approximately describes the processes of dissolution and transport of drug microcrystals to the target sites in a living organism, taking into account complex dissolution kinetics of drug particles. This article is part of the theme issue ‘Patterns in soft and biological matters’.

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19

He, Li Jun, De Mei Xu, Nan Hu, Ting Ting Li, Jing Ming Zhong, Zhan Hong Wang, Ben Shuang Sun, Hui Ling Kang, and Shuo Wan. "Model Analysis on Particles Size Distribution of Beryllium Powder." Applied Mechanics and Materials 268-270 (December 2012): 336–39. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.336.

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A physics model was established for describing the particle size distribution of beryllium (Be) powder produced by impact attrition milling. In this model, two factors were considered: the first, the distribution of existing state of particles with different original kinetic energy should obey the Maxwell-Boltzmann statistics after impacted, it was that, being at higher energy level made big particles unstable, which were easy to be fractured into smaller pieces in impact attrition process, this influencing factor described as the negative exponential of particles size; the second, the tendency to remain low surface energy needed particles should keep big volume as much as possible, this effect defined as the cube of particles size. The actual particle size distribution of Be powder was resulted from the competition between these two factors. Calculating result from the model was in good agreement with data from measurement.

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20

Matrosov, Sergey Y. "Evaluations of the Spheroidal Particle Model for Describing Cloud Radar Depolarization Ratios of Ice Hydrometeors." Journal of Atmospheric and Oceanic Technology 32, no. 5 (May 2015): 865–79. http://dx.doi.org/10.1175/jtech-d-14-00115.1.

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AbstractInformation on ice cloud particle nonsphericity is important for many practical applications ranging from modeling the cloud radiation impact to remote sensing of hydrometeor microphysical properties. Scanning cloud radars, which often measure depolarization ratio as a sole polarization variable, can provide a means for retrieving this information. The applicability of a spheroidal particle model (i.e., a regular ellipsoid that has two principal axes of the same length) is evaluated for describing depolarization properties of ice particles. It is shown that this simple model, which uses an aspect ratio as a single parameter characterizing particle nonsphericity, explains reasonably well the scatter of slant 45° linear depolarization ratio (SLDR) measurements versus direct estimates of the zenith direction backscatter enhancement observed during the Storm Peak Laboratory Cloud Property Validation Experiment (StormVEx) with the scanning W-band cloud radar (SWACR). Observed SLDR elevation angle patterns are also approximated reasonably well by this shape model. It is suggested that an SLDR difference between slant and zenith radar pointing can be used for prospective remote sensing methods of inferring particle aspect ratio from cloud radar depolarization measurements. Depending on mass–size relations, the value of this difference corresponding to median zenith reflectivity enhancement observed during StormVEx relates to aspect ratios of about 0.5 ± 0.2, which generally agrees with typical aspect ratios of ice particles. Expected aspect ratio retrieval uncertainties within the spheroidal shape model and the use of different types of radar depolarization ratio measurements are discussed. A correction for estimated zenith direction reflectivity enhancements due to particle nonsphericity is suggested.

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21

Mahler, Dylan H., Lee Rozema, Kent Fisher, Lydia Vermeyden, Kevin J. Resch, Howard M. Wiseman, and Aephraim Steinberg. "Experimental nonlocal and surreal Bohmian trajectories." Science Advances 2, no. 2 (February 2016): e1501466. http://dx.doi.org/10.1126/sciadv.1501466.

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Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed “surreal” when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality.

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22

Lazkoz, Ruth, and Juan Antonio Valiente Kroon. "The Newtonian limit of space-times describing uniformly accelerated particles." Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences 460, no. 2044 (April 8, 2004): 995–1016. http://dx.doi.org/10.1098/rspa.2003.1172.

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23

Rogers, W. A. "The Prediction of Wear in Fluidized Beds." Journal of Pressure Vessel Technology 117, no. 2 (May 1, 1995): 142–49. http://dx.doi.org/10.1115/1.2842101.

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A procedure is formulated to model impact and abrasion wear of surfaces exposed to a fluidized bed. A methodology adapting a single-particle wear model and the kinetic theory of gases to granular flows is used to develop a model accounting for impact wear from all possible particle collisions. Abrasive wear is modeled using a single-particle abrasion model adapted to describe the effects of many abrading particles. Parameters describing granular flow are necessary for evaluation of the resulting wear expressions. They are determined by numerical solution of the conservation equations describing fluidized-bed hydrodynamics. Additional parameters appear in the wear expressions which describe the contact between individual fluidized particles and the wearing surface. These are determined by an optimization procedure which minimizes error between predicted and measured wear rates. The modeling procedure was used to analyze several bubbling and turbulent fluidized bed experiments with single-tube and tube bundle configurations. Quantitative agreement between the measured and predicted wear rates was found, with some exceptions for local wear predictions. This work demonstrates a methodology for wear predication in fluidized beds.

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24

Izvekov, Sergei, and Betsy M. Rice. "On the importance of shear dissipative forces in coarse-grained dynamics of molecular liquids." Physical Chemistry Chemical Physics 17, no. 16 (2015): 10795–804. http://dx.doi.org/10.1039/c4cp06116k.

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In this work we demonstrate from first principles that the shear frictions describing dissipative forces in the direction normal to the vector connecting the coarse-grained (CG) particles in dissipative particle dynamics (DPD) could be dominant for certain real molecular liquids at high-resolution coarse-graining.

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25

Brodet, Eyal. "The Total Energy and Momentum Stored in a Particle." Applied Physics Research 9, no. 2 (March 17, 2017): 65. http://dx.doi.org/10.5539/apr.v9n2p65.

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In this paper we reconsider the conventional expressions given by special relativity to the energy and momentum of a particle. In the current framework, the particle's energy and momentum are computed using the particle's rest mass, M and rest mass time, t_m=h/M c^2 where t_m has the same time unit as conventionally used for the light velocity c. Therefore it is currently assumed that this definition of time describes the total kinetic and mass energy of a particle as given by special relativity. In this paper we will reexamine the above assumption and suggest describing the particle's energy as a function of its own particular decay time and not with respect to its rest mass time unit. Moreover we will argue that this rest mass time unit currently used is in fact the minimum time unit defined for a particle and that the particle may have more energy stored with in it. Experimental ways to search for this extra energy stored in particles such as electrons and photons are presented.

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Finch, Gregory L., and Richard G. Cuddihy. "Eds Of Radioactive Particles By Self-Induced Fluorescence." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 238–39. http://dx.doi.org/10.1017/s042482010013479x.

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The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

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VAN HERWAARDEN, ONNO A., and JOHAN GRASMAN. "DISPERSIVE GROUNDWATER FLOW AND POLLUTION." Mathematical Models and Methods in Applied Sciences 01, no. 01 (March 1991): 61–81. http://dx.doi.org/10.1142/s0218202591000058.

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By solving asymptotically the Dirichlet problem for the backward Kolmogorov equation describing the random walk of a particle in a dispersive flow, it is computed at what rate contaminated particles cross the boundary of a protected zone. The method also yields an estimate of the expected arrival time.

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28

Tomanovic, Ivan, Srdjan Belosevic, Aleksandar Milicevic, Nenad Crnomarkovic, and Dragan Tucakovic. "Numerical tracking of sorbent particles and distribution during gas desulfurization in pulverized coal-fired furnace." Thermal Science 21, suppl. 3 (2017): 759–69. http://dx.doi.org/10.2298/tsci160212196t.

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Furnace sorbent injection for sulfur removal from flue gas presents a challenge, as the proper process optimization is of crucial importance in order to obtain both high sulfur removal rates and good sorbent utilization. In the simulations a two-phase gas-particle flow is considered. Pulverized coal and calcium-based sorbent particles motion is simulated inside of the boiler furnace. It is important to determine trajectories of particles in the furnace, in order to monitor the particles heat and concentration history. A two-way coupling of the phases is considered ? influence of the gas phase on the particles, and vice versa. Particle-to-particle collisions are neglected. Mutual influence of gas and dispersed phase is modeled by corresponding terms in the transport equations for gas phase and the equations describing the particles turbulent dispersion. Gas phase is modeled in Eulerian field, while the particles are tracked in Lagrangian field. Turbulence is modeled by the standard k-? model, with additional terms for turbulence modulation. Distribution, dispersion and residence time of sorbent particles in the furnace have a considerable influence on the desulfurization process. It was shown that, by proper organization of process, significant improvement considering emission reduction can be achieved.

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Kislenko, Volodymyr, Liliya Oliynyk, and Svyatoslav Ivanyshyn. "The Model of Metal Oxide Particle Formation from Water Solutions of Salts." Chemistry and Chemical Technology 4, no. 2 (June 15, 2010): 95–100. http://dx.doi.org/10.23939/chcht04.02.095.

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The model describing the formation of metal oxide particles from water solutions of salts was suggested. Dependence of instability constants of metal complexes and ionization constants of oxygen containing inorganic acids on the electron density upon the central ion or atom allows to calculate these values for metal hydroxides. Equations describing the number of metal ions in polyion, the concentration of polyions in solution, the number of metal ions in primary metal oxide particles and their concentration in the system were suggested.

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30

Dariescu, Marina-Aura, and Ciprian Dariescu. "Heun Functions Describing Bosons and Fermions on Melvin’s Spacetime." Advances in High Energy Physics 2018 (June 11, 2018): 1–7. http://dx.doi.org/10.1155/2018/1953586.

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31

Попов, Евгений, and Evgeniy Popov. "RESEARCH OF THE EJECTING PROPERTIES OF A POLYFRACTION BULK MATERIAL FLOW." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 3, no. 3 (March 25, 2018): 46–51. http://dx.doi.org/10.12737/article_5abfc9b98fb328.24921610.

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This work is aimed at confirming the adequacy of the probabilistic and statistical approach to determining the aerodynamic resistance coefficient of particles in a flow of the free falling polyfractional material, suggested by the author. The aerodynamic resistance coefficient of particles in a flow of falling material is defined by calculating the probability of finding particles out of air shadows of the neighboring particles. The laboratory experiment was performed on the offered experimental samples of bulk materials having different particle size distribution, but the identical average diameter of particles. The design of a laboratory experimental installation which allows determining the consumption of air, ejected by a polyfractional material flow, was described. The amount of the air, ejected with experimental samples, depends on their particle size distribution that confirms the insufficiency of describing the properties of bulk material only with the average diameter value. The given comparison of results of the analytical calculations with experimental data shows the reliability and adequacy of the calculated values.

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Sánchez-Ccoyllo, Odón R., Carol Geimy Ordoñez-Aquino, Jessica Arratea-Morán, Nélida S. Marín-Huachaca, and Warren Reátegui-Romero. "Describing Aerosol and Assessing Health Effects in Lima, Peru." International Journal of Environmental Science and Development 12, no. 12 (2021): 355–62. http://dx.doi.org/10.18178/ijesd.2021.12.12.1361.

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The current study aims to discover the chemical-morphological characteristics of PM10 through the analysis of Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Scanning Electron Microscopy (SEM), respectively, in the Metropolitan Area of Lima (MEAL) in the period from January 04 to 18, 2019. The study also aims to analyze the aerosol optical depth (AOD) in the period from January 1, 2014 to October 15, 2020. The effect of the PM2.5 concentrations on health in 2016 has also been quantified. The results indicate that the daily PM10 value of 50 μg/m3 recommended by the World Health Organization was exceeded on 75% of the monitored days. The morphological analysis of PM10 demonstrated the presence of particles of anthropogenic and geogenic origin. Particles from building activities and secondary aerosol formation were found, as well as particles associated with the resuspension of soil and marine aerosols. In 2016, 718, 1426, and 4295 cases of all-cause mortality, on average, could have been avoided in the MEAL if the annual average of PM2.5 would have decreased from 26.53 μg/m3 to 23.88 μg/m3, 21.22 μg/m3, or 10 μg/m3, respectively. In 2016, 1.58%, 3.14% and 9.47% of all causes are respectively attributed to fine aerosol (PM2.5) over 23.88 μg/m3, 21.22 μg/m3, and 10 μg/m3. Policy makers to legally reduce the PM2.5 concentrations in the MEAL could use this result.

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33

Gambaryan, Mark M., and Mikhail D. Malykh. "On the many-body problem with short-range interaction." Discrete and Continuous Models and Applied Computational Science 30, no. 1 (February 25, 2022): 52–61. http://dx.doi.org/10.22363/2658-4670-2022-30-1-52-61.

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The classical problem of the interaction of charged particles is considered in the framework of the concept of short-range interaction. Difficulties in the mathematical description of short-range interaction are discussed, for which it is necessary to combine two models, a nonlinear dynamic system describing the motion of particles in a field, and a boundary value problem for a hyperbolic equation or Maxwells equations describing the field. Attention is paid to the averaging procedure, that is, the transition from the positions of particles and their velocities to the charge and current densities. The problem is shown to contain several parameters; when they tend to zero in a strictly defined order, the model turns into the classical many-body problem. According to the Galerkin method, the problem is reduced to a dynamic system in which the equations describing the dynamics of particles, are added to the equations describing the oscillations of a field in a box. This problem is a simplification, different from that leading to classical mechanics. It is proposed to be considered as the simplest mathematical model describing the many-body problem with short-range interaction. This model consists of the equations of motion for particles, supplemented with equations that describe the natural oscillations of the field in the box. The results of the first computer experiments with this short-range interaction model are presented. It is shown that this model is rich in conservation laws.

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NIKOLIĆ, HRVOJE. "QFT AS PILOT-WAVE THEORY OF PARTICLE CREATION AND DESTRUCTION." International Journal of Modern Physics A 25, no. 07 (March 20, 2010): 1477–505. http://dx.doi.org/10.1142/s0217751x10047889.

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States in quantum field theory (QFT) are represented by many-particle wave functions, such that a state describing n particles depends on n space–time positions. Since a general state is a superposition of states with different numbers of particles, the wave function lives in the configuration space identified with a product of an infinite number of four-dimensional Minkowski space–times. The squared absolute value of the wave function is interpreted as the probability density in the configuration space, from which the standard probabilistic predictions of QFT can be recovered. Such a formulation and probabilistic interpretation of QFT allows one to interpret the wave function as a pilot wave that describes deterministic particle trajectories, which automatically includes a deterministic and continuous description of particle creation and destruction. In particular, when the conditional wave function associated with a quantum measurement ceases to depend on one of the space–time coordinates, then the 4-velocity of the corresponding particle vanishes, describing a trajectory that stops at a particular point in space–time. In a more general situation a dependence on this space–time coordinate is negligibly small but not strictly zero, in which case the trajectory does not stop but the measuring apparatus still behaves as if this particle has been destroyed.

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35

Przekop, Rafał, and Leon Gradoń. "Non-steady-state aerosol filtration in nanostructured fibrous media." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 369, no. 1945 (June 28, 2011): 2476–84. http://dx.doi.org/10.1098/rsta.2011.0063.

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The filtration of aerosol particles using composites of nano- and microsized fibrous structures is a promising method for the effective separation of nanoparticles from gases. A multi-scale physical system describing the flow pattern and particle deposition at a non-steady-state condition requires an advanced method of modelling. The combination of lattice Boltzmann and Brownian dynamics was used for analysis of the particle deposition pattern in a fibrous system. The dendritic structures of deposits for neutral and charged fibres and particles are present. The efficiency of deposition, deposit morphology, porosity and fractal dimension were calculated for a selected operational condition of the process.

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36

Vechernin, Vladimir. "String model calculation of the strongly intensive observables for multiplicities in two windows." EPJ Web of Conferences 204 (2019): 06004. http://dx.doi.org/10.1051/epjconf/201920406004.

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We calculate the strongly intensive observables for multiplicities in two rapidity windows in the model with independent identical strings taking into account the charge sign of particles. We express the observables through the string pair correlation functions describing the correlations between the same and opposite sign particles produced in a string decay. We extract these charge-wise string two-particle correlation functions from the ALICE data on the forward-backward correlations and the balance function. Using them we predict the behavior of the charge-wise strongly intensive observables in the model with independent identical strings.

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37

Karwowski, Jacek, and Lech Cyrnek. "A Class of Exactly Solvable Schrödinger Equations." Collection of Czechoslovak Chemical Communications 70, no. 7 (2005): 864–80. http://dx.doi.org/10.1135/cccc20050864.

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An algebraic approach to solving a class of one-particle Schrödinger equations is presented. As an example, quasi-exact solutions of the eigenvalue problem of a Hamiltonian describing two interacting particles confined in a parabolic well are obtained. This example constitutes a unification and a generalization of several models known in the literature, as the ones of Taut (Phys. Rev. A 1993, 48, 3561) and of Samanta and Ghosh (Phys. Rev. A 1990, 42, 1178). Two confined particles interacting by Coulomb forces and the nuclear motion of a diatomic molecule are discussed as practical implementations.

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Neice, Andrew. "A Hamiltonian for Describing Zero Rest Mass Particles in Free Space." Physics Essays 17, no. 4 (December 1, 2004): 536–41. http://dx.doi.org/10.4006/1.3025717.

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Tawfik, A. M., H. Fichtner, R. Schlickeiser, and A. Elhanbaly. "Analytical study of fractional equations describing anomalous diffusion of energetic particles." Journal of Physics: Conference Series 869 (June 2017): 012050. http://dx.doi.org/10.1088/1742-6596/869/1/012050.

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Stańczy, Robert. "On an evolution system describing self-gravitating particles in microcanonical setting." Monatshefte für Mathematik 162, no. 2 (April 14, 2010): 197–224. http://dx.doi.org/10.1007/s00605-010-0218-8.

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41

Nymmik, R. A., M. I. Panasyuk, T. I. Pervaya, and A. A. Suslov. "An analytical model, describing dynamics of galactic cosmic ray heavy particles." Advances in Space Research 14, no. 10 (October 1994): 759–63. http://dx.doi.org/10.1016/0273-1177(94)90538-x.

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42

Dalirian, M., H. Keskinen, L. Ahlm, A. Ylisirniö, S. Romakkaniemi, A. Laaksonen, A. Virtanen, and I. Riipinen. "CCN activation of fumed silica aerosols mixed with soluble pollutants." Atmospheric Chemistry and Physics 15, no. 7 (April 9, 2015): 3815–29. http://dx.doi.org/10.5194/acp-15-3815-2015.

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Abstract. Particle–water interactions of completely soluble or insoluble particles are fairly well understood but less is known of aerosols consisting of mixtures of soluble and insoluble components. In this study, laboratory measurements were performed to investigate cloud condensation nuclei (CCN) activity of silica particles mixed with ammonium sulfate (a salt), sucrose (a sugar) and bovine serum albumin known as BSA (a protein). The agglomerated structure of the silica particles was investigated using measurements with a differential mobility analyser (DMA) and an aerosol particle mass analyser (APM). Based on these data, the particles were assumed to be compact agglomerates when studying their CCN activation capabilities. Furthermore, the critical supersaturations of particles consisting of pure and mixed soluble and insoluble compounds were explored using existing theoretical frameworks. These results showed that the CCN activation of single-component particles was in good agreement with Köhler- and adsorption theory based models when the agglomerated structure was accounted for. For mixed particles the CCN activation was governed by the soluble components, and the soluble fraction varied considerably with particle size for our wet-generated aerosols. Our results confirm the hypothesis that knowing the soluble fraction is the key parameter needed for describing the CCN activation of mixed aerosols, and highlight the importance of controlled coating techniques for acquiring a detailed understanding of the CCN activation of atmospheric insoluble particles mixed with soluble pollutants.

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Deng, Yimin, Raf Dewil, Lise Appels, Huili Zhang, Shuo Li, and Jan Baeyens. "The Need to Accurately Define and Measure the Properties of Particles." Standards 1, no. 1 (August 12, 2021): 19–38. http://dx.doi.org/10.3390/standards1010004.

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When dealing with powders, a fundamental knowledge of their physical parameters is indispensable, with different methods and approaches proposed in literature. Results obtained differ widely and it is important to define standards to be applied, both toward the methods of investigation and the interpretation of experimental results. The present research intends to propose such standards, while defining general rules to be respected. Firstly, the problem of defining the particle size is inspected. It was found that describing the size of a particle is not as straightforward as one might suspect. Factors of non-sphericity and size distributions make it impossible to put ‘size’ in just one number. Whereas sieving can be used for coarser particles of a size in excess of about 50 µm, instrumental techniques span a wide size range. For fine particles, the occurrence of cohesive forces needs to be overcome and solvents, dispersants and sample mixing need to be applied. Secondly, the shape of the particles is examined. By defining sphericity, irregularly shaped particles are described. Finally, the density of particles, of particle assemblies and their voidage (volume fraction of voids) and the different ways to investigate them are explored.

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44

Khabarova, Olga V., Olga E. Malandraki, Gary P. Zank, Gang Li, Jakobus A. le Roux, and Gary M. Webb. "Re-Acceleration of Energetic Particles in Large-Scale Heliospheric Magnetic Cavities." Proceedings of the International Astronomical Union 13, S335 (July 2017): 75–81. http://dx.doi.org/10.1017/s1743921318000285.

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AbstractCase studies show that some energetic particle flux enhancements up to MeV/nuc. observed at 1 AU cannot be treated as a consequence of particle acceleration at shocks or during flares. Atypical energetic particle events (AEPEs) are often detected during crossings of magnetic cavities formed by strong current sheets of various origins in the solar wind. Such cavities confine small-scale magnetic islands (SMIs) produced by magnetic reconnection. SMIs, in turn, trap and re-accelerate energetic particles according to predictions based on the theory of Zank et al. describing stochastic particle energization in the supersonic solar wind via numerous dynamically interacting SMIs. AEPEs possess energies that overlap SEP events and can be an important component in understanding space weather.

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45

SHERIDAN, L., N. PAUNKOVIĆ, Y. OMAR, and S. BOSE. "DISCRETE TIME QUANTUM WALK ON A LINE WITH TWO PARTICLES." International Journal of Quantum Information 04, no. 03 (June 2006): 573–83. http://dx.doi.org/10.1142/s0219749906002006.

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We introduce the idea of a quantum walk with two particles and study it for the case of a discrete time walk on a line. We consider both separable and maximally entangled initial conditions, and show how the entanglement and the relative phase between the states describing the coin degree of freedom of each particle will influence the evolution of the quantum walk. In particular, these factors will have consequences for the distance between the particles and the probability of finding them at a given point, yielding results that cannot be obtained from a separable initial state, be it pure or mixed. Finally, we review briefly proposals for implementations.

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46

Mişicu, Ş., I. N. Mishustin, and W. Greiner. "Q-balls of clusterized baryonic matter." Modern Physics Letters A 32, no. 01 (December 15, 2016): 1750010. http://dx.doi.org/10.1142/s0217732317500109.

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Properties of baryonic matter made of nucleons and [Formula: see text]-particles are studied within a relativistic mean-field (RMF) model. The Lagrangian describing the relativistic field [Formula: see text] of [Formula: see text]-particles is allowed to contain also self-interaction terms. Various types of RMF parametrizations are employed to calculate the energy of [Formula: see text]-particles embedded in the baryonic matter. We first consider baryonic systems with small admixtures of [Formula: see text]-particles and calculate the energy spectrum as a function of baryon density. Then we turn to the case of pure [Formula: see text]-matter and derive once again the energy spectrum, this time as a function of [Formula: see text]-particle density, with and without quartic self-interaction. In the second part of the paper, we focus on the ground-state properties (energy per particle, radii of the spherical lumps made of [Formula: see text]-particles) of charge neutralized Q-balls formed of baryonic [Formula: see text]-particles for the case of linear [Formula: see text] and [Formula: see text] fields and nonlinear (quartic[Formula: see text]+[Formula: see text]sextic) self-interactions of the [Formula: see text] field.

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47

YA. AREF'EVA, IRINA, GABRIELE FERRETTI, and ALEXEY S. KOSHELEV. "TAMING THE NON-ABELIAN BORN–INFELD ACTION." Modern Physics Letters A 13, no. 30 (September 28, 1998): 2399–413. http://dx.doi.org/10.1142/s0217732398002564.

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We show how to reduce the non-Abelian Born–Infeld action describing the interaction of two D-particles to the sum of elliptic integrals depending on simple kinematic invariants. This representation gives explicitly all α′ corrections to D-particle dynamics. The α′ corrections induce a stabilization of the classical trajectories such as the "eikonal" which are unstable within the Yang–Mills approximation.

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48

BIGAZZI, FRANCESCO, and LUCA LUSANNA. "SPINNING PARTICLES ON SPACELIKE HYPERSURFACES AND THEIR REST FRAME DESCRIPTION." International Journal of Modern Physics A 14, no. 09 (April 10, 1999): 1429–84. http://dx.doi.org/10.1142/s0217751x99000749.

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A new spinning particle with a definite sign of the energy is defined on spacelike hypersurfaces after a critical discussion of the standard spinning particles. It is the pseudoclassical basis of the positive energy [Formula: see text] [or negative energy [Formula: see text]] part of the [Formula: see text] solutions of the Dirac equation. The study of the isolated system of N such spinning charged particles plus the electromagnetic field leads to their description in the rest frame Wigner-covariant instant form of dynamics on the Wigner hyperplanes orthogonal to the total four-momentum of the isolated system (when it is timelike). We find that on such hyperplanes these spinning particles have a nonminimal coupling only of the type "spin–magnetic field," like the nonrelativistic Pauli particles to which they tend in the nonrelativistic limit. The Lienard–Wiechert potentials associated with these charged spinning particles are found. Then, a comment is made on how to quantize the spinning particles respecting their fibered structure describing the spin structure.

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49

Degond, Pierre, and Sara Merino-Aceituno. "Nematic alignment of self-propelled particles: From particle to macroscopic dynamics." Mathematical Models and Methods in Applied Sciences 30, no. 10 (September 2020): 1935–86. http://dx.doi.org/10.1142/s021820252040014x.

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Starting from a particle model describing self-propelled particles interacting through nematic alignment, we derive a macroscopic model for the particle density and mean direction of motion. We first propose a mean-field kinetic model of the particle dynamics. After diffusive rescaling of the kinetic equation, we formally show that the distribution function converges to an equilibrium distribution in particle direction, whose local density and mean direction satisfies a cross-diffusion system. We show that the system is consistent with symmetries typical of a nematic material. The derivation is carried over by means of a Hilbert expansion. It requires the inversion of the linearized collision operator for which we show that the generalized collision invariants, a concept introduced to overcome the lack of momentum conservation of the system, plays a central role. This cross-diffusion system poses many new challenging questions.

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50

Krasovsky, V. L. "The propagation of a plasma wave with trapped particles in a weakly inhomogeneous plasma." Journal of Plasma Physics 47, no. 2 (April 1992): 235–48. http://dx.doi.org/10.1017/s0022377800024193.

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The propagation of a Langmuir wave with a small group of trapped particles in a weakly non-uniform plasma along a density gradient is considered. The dynamics of trapped electrons accelerated by the wave is investigated in the adiabatic approximation, including the relativistic case. The set of equations describing the self-consistent spatial evolution of the wave—trapped-particles system is obtained and analysed. It is shown that the possibility exists of wave transmission through a classically forbidden barrier as a consequence of the reversibility of the wave—particle interaction. The conditions of validity of the theory developed are also discussed.

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