Clusters Of Particles Research Articles

Revealing the percolation–agglomeration transition in polymer nanocomposites via MD-informed continuum RVEs with elastoplastic interphases

This contribution builds the concluding step of a multiscale approach to effectively capture the mechanical behavior of polymer nanocomposites (PNCs), in this case, silica-modified polystyrene. By introducing continuum-based representative volume elements (RVEs) that employ previously identified elastoplastic property gradients for the interphases surrounding the fillers, the effects of particle size, particle volume fraction, and agglomeration on the mechanical performance are investigated. Uniaxial tension tests are simulated with the respective finite-element RVEs, and stress–strain curves are derived. The elastic and plastic material properties of the RVE can then be extracted and analyzed quantitatively by fitting the stress–strain curves with a Voce-type elastoplasticity formulation.At small degrees of agglomeration, i.e., good particle dispersion, in combination with sufficiently large particle volume fraction, percolation bands form, leading to improved elastic and plastic properties. Higher degrees of agglomeration or particle clusters behave like large single particles, which has an adverse effect, i.e., the nanoscale size effect is thereby neutralized. Therefore, the precise MD-informed elastoplastic interphase representation of our RVEs enables the investigation of the transition from beneficial percolation to unfavorable agglomeration. Ultimately, this contribution establishes a link between the effects of particle size, particle volume fraction, agglomeration, and percolation, which have so far only been discussed separately in the literature.Our methodology offers new insights into the structure–property relations of PNCs and their resulting mechanical behavior. The underlying multiscale approach with a systematic transition from molecular to microscopic scales is required to complement experimental observations and exploit the full potential of PNCs.

Influence of porosity on the Umov effect in silicate and organic refractory aggregates

This study investigates the influence of porosity on the Umov effect, a phenomenon observed in the scattering of light from celestial objects. The Umov effect describes an inverse relationship between the degree of linear polarization and the object’s reflectance (geometric albedo). To study the dependence of porosity on the Umov effect, a wide range of porosity (i.e., from 0.64 to 0.99) is considered. Four types of aggregates, ballistic cluster–cluster aggregate (BCCA), ballistic particle cluster aggregate (BPCA) or ballistic agglomeration (BA), ballistic agglomeration with one migration (BAM1), and ballistic agglomeration with two migrations (BAM2) each having porosity 0.99, 0.87, 0.74, and 0.64 are considered in this study. The multi-sphere T-matrix code is utilized to calculate the linear polarization and geometric albedo (A) considering silicate and organic refractory compositions for monodisperse aggregates. The results are reported for six different wavelengths, ranging from near-ultraviolet to the visible spectrum. When the polarization maximum (Pmax) is plotted against the geometric albedo (A) on a logarithmic scale, an inverse relation is observed. This relation exhibits non-linear changes, fitted by a second-degree polynomial equation, as the porosity changes from 0.64 to 0.99. This finding constitutes one of the interesting results of our study. In addition, the study explores the effect of porosity (P) on the ratio between log(Pmax) and log(A), showing a non-linear relationship. A comparison is drawn between the results obtained from organic refractory compositions and amorphous silicate compositions, emphasizing the importance of porosity and wavelength in regulating the Umov effect. In addition, the research investigates how mixing affects the results at different wavelengths, assuming the aggregates are blends of organic refractory and amorphous silicate compositions. The computations have also been performed for polydisperse aggregates (considering BCCA, BA, BAM1, and BAM2 structures) at a wavelength of 0.45 μm for silicate compositions, which also showed a non-linear dependence as observed in the case of monodisperse aggregates.

Al and A356 Alloy Foam Castings Modified with Low Concentrations of Nano-Sized Particles: Structural Study and Compressive Strength Tests

Aluminum and A356 alloy foam castings are produced using a melt-foaming method. Prior to foaming, the melt is modified with nano-sized particles (SiC, TiN, or Al2O3). The nano-sized particles are mixed with micro-sized Al particles, which are ultrasonically treated and hot-extruded. Thus, the so-called “modifying nano-composition” is obtained. The resulting compositions are introduced into the melt of the Al foam at the following mass concentrations of nanoparticles: SiC: 0.038 wt. %; TiN: 0.045 wt. %; and Al2O3: 0.046 wt. %. For the A356 foam, we use the following concentrations: SiC: 0.039 wt. %; TiN: 0.052 wt. %; and Al2O3: 0.086 wt. %. The macrostructure of the foam castings is investigated by CT scanning and 3D analysis. The pore size distributions and accumulative fraction dependencies are determined for all samples. The microstructure of the foam castings is investigated by SEM-EDS analysis. The results confirmed the presence of individual nano-sized particles, as well as clusters of particles in foam walls. The conducted compression tests show a significant increase in the plateau stress (up to 237%) of the modified aluminum foam castings compared to non-modified castings. However, a similar effect of the nano-compositions on A356 alloy foam castings is not observed. The obtained results show that the above-indicated concentrations of nanoparticles can positively influence the mechanical properties of aluminum foam castings. The novelty of the current study is two-fold: (1) such low concentrations of added nanoparticles have never been used before to alter Al foam’s properties, and (2) an original method of introducing the nanoparticles into the melt is applied in the form of nano-compositions.

Asymptotic analysis of particle cluster formation in the presence of anchoring sites

The aggregation or clustering of proteins and other macromolecules plays an important role in the formation of large-scale molecular assemblies within cell membranes. Examples of such assemblies include lipid rafts, and postsynaptic domains (PSDs) at excitatory and inhibitory synapses in neurons. PSDs are rich in scaffolding proteins that can transiently trap transmembrane neurotransmitter receptors, thus localizing them at specific spatial positions. Hence, PSDs play a key role in determining the strength of synaptic connections and their regulation during learning and memory. Recently, a two-dimensional (2D) diffusion-mediated aggregation model of PSD formation has been developed in which the spatial locations of the clusters are determined by a set of fixed anchoring sites. The system is kept out of equilibrium by the recycling of particles between the cell membrane and interior. This results in a stationary distribution consisting of multiple clusters, whose average size can be determined using an effective mean-field description of the particle concentration around each anchored cluster. In this paper, we derive corrections to the mean-field approximation by applying the theory of diffusion in singularly perturbed domains. The latter is a powerful analytical method for solving two-dimensional (2D) and three-dimensional (3D) diffusion problems in domains where small holes or perforations have been removed from the interior. Applications range from modeling intracellular diffusion, where interior holes could represent subcellular structures such as organelles or biological condensates, to tracking the spread of chemical pollutants or heat from localized sources. In this paper, we take the bounded domain to be the cell membrane and the holes to represent anchored clusters. The analysis proceeds by partitioning the membrane into a set of inner regions around each cluster, and an outer region where mean-field interactions occur. Asymptotically matching the inner and outer stationary solutions generates an asymptotic expansion of the particle concentration, which includes higher-order corrections to mean-field theory that depend on the positions of the clusters and the boundary of the domain. Motivated by a recent study of light-activated protein oligomerization in cells, we also develop the analogous theory for cluster formation in a three-dimensional (3D) domain. The details of the asymptotic analysis differ from the 2D case due to the contrasting singularity structure of 2D and 3D Green’s functions.Graphical abstract2D model of diffusion-based protein cluster formation in the presence of anchoring cites and particle recycling. a A set of N anchoring sites at positions xj\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\ extbf{x}}_j$$\\end{document}, j=1,…,N\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$j=1,\\ldots ,N$$\\end{document}, in a bounded domain Ω\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega $$\\end{document}. b Diffusing particles accumulate at the anchoring sites resulting in the formation of particle aggregates or clusters Uj\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {U}}}_j$$\\end{document}. c The clusters are dynamically maintained by a combination of lateral diffusion outside the clusters and particle recycling

Viscosity model for the middle fraction of Atasu-Alashankou oil sludge

The temperature dependence of dynamic viscosity was calculated on the basis of a new cluster-association equation, which was derived within the framework of the concept of chaotic particles. It was shown that the degree of cluster association naturally decreases with an increase in temperature, on average corresponding to the arrangement of three to four cluster particles in the association. For the first time, the values of the activation energy per monomer were obtained when assigning the activation energy to the average number of clusters.

Multiphase flow simulation in hybrid porous structure

Recent research has primarily focused on creating biporous and hybrid porous structures with multiple pore sizes and length scales to optimize capillary pressure and permeability. Despite numerous experimental investigations on biporous and hybrid media, there is a noticeable absence of numerical simulations that explore the multiphase flow within these media. Therefore, the present study aims to conduct a pore-scale numerical simulation of two-phase flow in a biporous structure. The biporous structure is proposed by arranging clusters of solid particles in a staggered regular pattern, with each cluster consisting of closely packed particles. The dimensions and characteristics of the simulated structure are based on previous experimental literature on biporous and hybrid media. A monoporous structure simulation is also included for comparison with biporous results. ANSYS Fluent is utilized to carry out the numerical simulations of capillary pumping flow. The simulation results indicate that the permeability and average capillary pressure of the biporous media are four times and over one and a half times higher, respectively, compared to those of the monoporous media. The presence of smaller pathways within each cluster of a biporous and hybrid porous media enhances the capillary effect in comparison to conventional monoporous structures. Additionally, the larger pores between the clusters contribute to a higher permeability of the hybrid porous structure. As a result, the combined effect of increased capillary action and higher permeability leads to improved performance of the hybrid porous structure. Overall, the proposed simplified biporous geometry accurately models fluid flow in real, complex biporous and hybrid structures.

Statistics of a granular cluster ensemble at a liquid-solid-like phase transition.

We report on the construction of a granular network of particles to study the formation, evolution, and statistical properties of clusters of particles developing at the vicinity of a liquid-solid-like phase transition within a vertically vibrated quasi-two-dimensional granular system. Using the data of particle positions and local order from Castillo etal. [G. Castillo, N. Mujica, and R. Soto, Phys. Rev. Lett. 109, 095701 (2012)0031-900710.1103/PhysRevLett.109.095701], we extract granular clusters taken as communities of the granular network via modularity optimization. Each one of these communities is a patch of particles with a very well defined local orientational order embedded within an array of other patches forming a complex cluster network. The distributions of cluster sizes and lifespans for the cluster network depend on the distance to the liquid-solid-like phase transition of the quasi-two-dimensional granular system. Specifically, the cluster size distribution displays a scale-invariant behavior for at least a decade in cluster sizes, while cluster lifespans grow monotonically with each cluster size. We believe this systematic community analysis for clustering in granular systems can help to study and understand the spatiotemporal evolution of mesoscale structures in systems displaying out-of-equilibrium phase transitions.

Investigation on laser-induced bubble collapse among triple particles based on high-frame-rate photography and the Kelvin impulse model

In fluid machinery, the concurrent presence of cavitation bubbles and particle clusters leads to considerably damage to material surfaces. This study investigates the dynamics of a bubble situated among triple particles based on the Kelvin impulse model and high-frame-rate photography, focusing on the impact of the dimensionless distance of particles and the bubble size. Specifically, the jet, bubble motion, and bubble interface evolution characteristics are quantitatively evaluated. The following conclusions are obtained: (1) The collapse shapes of the bubble can be divided into three typical cases: equilateral triangle shape, isosceles triangle shape, and arcuate shape. (2) Among the triple particles, four zero-Kelvin-impulse locations are present, around which the jet direction is extremely sensitive to the bubble initial position. As the bubble initial position moves along the central line, the bubble motion direction dramatically changes during its collapse. (3) The relative position of bubble and particles is the key parameter that affects the bubble dynamics. As the bubble–particle distance decreases, the non-uniformity of bubble collapse morphology and the bubble motion distance will become more significant.

Temperature statistics of settling particles in homogeneous isotropic turbulence

Heat transfer of settling particles in homogeneous isotropic turbulence is investigated in one-way coupled Eulerian–Lagrangian direct numerical simulations. In the absence of gravity, our observations highlight that there was a correlation between particles concentration and temperature fronts, which are characterized by high-temperature gradients. The particle clustering is mainly influenced by the preferential concentration and the non-local effect, the latter being the memory of their interaction with the flow along their trajectories. Nevertheless, gravity significantly affects the clustering of particles, which further influence the heat transfer of particles with the fluid. We find that the heat transfer of particles is intricately related to particle dynamic inertia and thermal inertia, which can be quantified by the particle Stokes number St and particle thermal Stokes number Stθ, respectively. In this study, we observe that the variance of particle temperature rate of change is independent of Stθ at small thermal inertia but inversely proportional to Stθ2 for large thermal inertia. In the presence of gravity, the variance converges to Stθ−1 for particles with negligible thermal inertia. Our findings reveal that the second-order structure function of the particle temperature, indicating the enhancement of Lagrangian scalar intermittency, adheres to a power-law behavior with limited thermal inertial particles in the dissipation region, denoted as r2. However, as Stθ increases, the power law of the structure function of the particle temperature is disrupted leading to ‘thermal caustics’. The present findings of the heat transfer behavior of settling particles advance the understanding of gravity effect, and are valuable for the modeling of heat transfer in particle-laden turbulent flows.

Far-Field Super-Resolution Optical Microscopy for Nanostructures in a Reflective Substrate

The resolution of an optical microscope is determined by the overall point spread function of the system. When examining structures significantly smaller than the wavelength of light, the contribution of the background or surrounding environment can profoundly affect the point spread function. This research delves into the impact of reflective planar substrate structures on the system’s resolution. We establish a comprehensive forward imaging model for a reflection-type confocal laser scanning optical microscope, incorporating vector field manipulation to image densely packed nanoparticle clusters. Both theoretical and experimental findings indicate that the substrate causes an interference effect between the background field and the scattered field from the nanoparticles, markedly enhancing the overall spatial resolution. The integration of vector field manipulation with an interferometric scattering approach results in superior spatial resolution for imaging isolated particles and densely distributed nanoscale particle clusters even with deep subwavelength gaps as small as 20 nm between them. However, the method still struggles to resolve nanoparticles positioned directly next to each other without any gap, necessitating further work to enhance the resolving ability. This may involve techniques like deconvolution or machine learning-based post-processing methods.

Mn/Co bimetallic catalyst immobilized on N-doped biochar for enhanced photocatalytic degradation of sulfanilamide in water

Single-atom catalyst has shown promising effect in photocatalysis. In particular, the construction of bimetallic catalytic sites can address the limitations of single-metallic catalysts, such as clustering and slow electron transfer, which enhances electron transfer between active sites and promotes photocatalytic activity. In this paper, Mn and Co bimetallic catalyst (Mn/Co@N-biochar) was developed by using the electronegativity difference of the bimetallic sites on N-doped biochar to construct catalytically active sites to enhance electron transfer. XRD and HR-TEM characterization confirmed that metal atoms were evenly dispersed within the carbon layer without aggregation or clustering of metal particles. The catalytic efficiency of Mn/Co@N-biochar was assessed through sulfanilamide (SNM) degradation experiments, demonstrating a remarkable degradation rate of 99.3% and a mineralization rate of 49.0%. These values were 10.45 times and 13.24 times more than that for biochar, respectively, indicating that the loading of bimetals greatly improved the photocatalytic activity. Furthermore, the doping of N atoms adjusted the electronic structure of adjacent C atoms and activated the free-flowing π electrons on the biochar surface, creating solid anchoring sites that facilitated efficient electron circulation between Mn and Co atomic sites. The higher local electron density at the Co-N4 site compared to the Mn-N4, created electron transfer channels, where Mn atoms (catalytic site) facilitated the flow of electrons to Co atoms (active site). This could rapidly generate the primary active species (‧OH and ‧O2-) to degrade SNM. Additionally, the stability and applicability of bimetallic catalysts in real water systems were also confirmed, providing valuable insights for the construction of bimetallic biochar structures to degrade organic pollutants in water.

Observation of liquid glass in molecular dynamics simulations.

Molecular anisotropy plays an important role in the glass transition of a liquid. Recently, a novel bulk glass state has been discovered by optical microscopy experiments on suspensions of ellipsoidal colloids. "Liquid glass" is a disordered analog of a nematic liquid crystal, in which rotation motion is hindered but particles diffuse freely. Global nematic order is suppressed as clusters of aligned particles intertwine. We perform Brownian dynamics simulations to test the structure and dynamics of a dense system of soft ellipsoidal particles. As seen in the experiments and in accordance with predictions from the mode coupling theory, on the time scale of our simulations, rotation motion is frozen but translation motion persists in liquid glass. Analyses of the dynamic structure functions for translation and rotation corroborates the presence of two separate glass transitions for rotation and translation, respectively. Even though the equilibrium state should be nematic, aligned structures remain small and orientational order rapidly decays with increasing size. Long-wavelength fluctuations are remnants of the isotropic-nematic transition.

Resolvent analysis of turbulent flow laden with low-inertia particles

We extend the resolvent framework to two-phase flows with low-inertia particles. The particle velocities are modelled using the equilibrium Eulerian model. We analyse the turbulent flow in a vertical pipe with Reynolds number of $5300$ (based on diameter and bulk velocity), for Stokes numbers $St^+=0-1$ , Froude numbers $Fr_z=-4,-0.4,0.4,4$ and $1/Fr_z = 0$ (gravity omitted). The governing equations are written in input–output form and a singular value decomposition is performed on the resolvent operator. As for single-phase flows, the operator is low rank around the critical layer, and the true response can be approximated using one singular vector. Even with a crude forcing model, the formulation can predict physical phenomena observed in Lagrangian simulations, such as particle clustering and gravitational effects. Increasing the Stokes number shifts the predicted concentration spectra to lower wavelengths; this shift also appears in the direct numerical simulation spectra and is due to particle clustering. When gravity is present, there are two critical layers, one for the concentration field, and one for the velocity field. For upward flow, the peak of concentration fluctuations shifts closer to the wall, in agreement with the literature. We explain this with the aid of the different locations of the two critical layers. Finally, the model correctly predicts the interaction of near-wall vortices with particle clusters. Overall, the resolvent operator provides a useful framework to explain and interpret many features observed in Lagrangian simulations. The application of the resolvent framework to higher $St^+$ flows in combination with Lagrangian simulations is also discussed.

Exploring the structural, optical, and dielectric characteristics of polyacrylamide gel synthesized CeMnO3 nanoparticles with Co & Ni ion doping

Nanostructured perovskite materials doped with transition metal ions have attracted significant attention due to their unique electronic and dielectric properties. In this study, we present the synthesis and thorough characterization of cobalt (Co) and nickel (Ni) ion-doped CeMnO3 (CMO) perovskite nanoparticles using a modified polyacrylamide gel method. Our structural analysis suggests that the perovskite phase stabilizes with an orthorhombic phase (Pbnm space group). Morphological analysis conducted via field emission scanning electron microscopy (FESEM) unveils the formation of clustered nanospherical particles. X-ray photoelectron spectroscopy (XPS) reveals mixed oxidation states of Ce, Mn, and Ni ions. Furthermore, UV–Vis and photoluminescence spectra analyses demonstrate a distinctive reduction in band gap and suppressed charge carrier recombination upon doping. The substitution of Ni and Co ions also enhances the screening effect, reducing Coulombic interaction between photoexcited electrons and holes and subsequently increasing the dielectric constant. Analysis of the Cole-Cole plot demonstrates the augmentation of capacitance with Ni substitution. These findings collectively suggest that the decreased dielectric loss and enhanced dielectric constant support the feasibility of these materials for application in storage devices.

Microstructure, mechanical and corrosion behavior of CrNx/Al2O3 multilayer films deposited by magnetron sputtering

A novel design was adopted to improve corrosion resistance of 2024 Al alloys by magnetron sputtering CrNx based multilayer films with Al2O3 intercalation. The multilayer films were composed of inhomogeneous structure, i.e., thick CrNx transition layer (∼2 μm) + CrNx/Al2O3 multilayer (∼1 μm). The effect of Al2O3 interlayer and modulation period on microstructure and performance of multilayer films were investigated. The nitride layer was dominated by Cr2N and CrN with minor Cr, while the Al2O3 layer displayed in the amorphous form. The intercalation of Al2O3 blocked the columnar growth in CrNx layers and refined the grains. As the period increased, the cluster particle size decreased and the mechanical properties increased, with the maximum hardness and modulus at CN-8 (19.13 GPa and 282.2 GPa). In addition, the multilayer structure enhanced the bonding between the film and the substrate, and has an improvement on the hard and brittle properties of the film. The multilayer films showed improved corrosion resistance than the CrNx mono-layer in 3.5 wt% NaCl solution. The film with CrNx-top layer showed superior corrosion resistance than the film with Al2O3-top layer. The increasing period also enhanced corrosion resistance, showing an excellent corrosion potential and corrosion current density (Ecorr=-0.538 V, icorr=0.96 μA·cm−2) at CN-8.

Accurate and High-Resolution Particle Mass Measurement Using a Peak Filtering Algorithm.

Charge detection quadrupole ion trap mass spectrometry (CD-QIT MS) is an effective way of achieving the mass analysis of microparticles with ultrahigh mass. However, its mass accuracy and resolution are still poor. To enhance the performance of CD-QIT MS, the resolution Rpeak of each peak in the mass spectra resulting from an individual particle was assessed, and a peak filtering algorithm that can filter out particle adducts and clusters with a lower Rpeak was proposed. By using this strategy, more accurate mass information about the analyzed particles could be obtained, and the mass resolution of CD-QIT MS was improved by nearly 2-fold, which was demonstrated by using the polystyrene (PS) particle size standards and red blood cells (RBCs). Benefiting from these advantages of the peak filtering algorithm, the baseline separation and relative quantification of 3 and 4 μm PS particles were achieved. To prove the application value of this algorithm in a biological system, the mass of yeast cells harvested at different times was measured, and it was found that the mixed unbudded and budded yeast cells, which otherwise would not be differentiable, were distinguished and quantified with the algorithm.

Particle topology-regulated relaxation dynamics in cluster-ordering.

The granular materials of soft particles (SPs) demonstrate unique viscoelasticity distinct from general colloidal and polymer systems. Exploiting dynamic light scattering measurements, together with molecular dynamics simulations, we study the diffusive dynamics of soft particle clusters (SPCs) with spherical and cylindrical brush topologies, respectively, in the melts of SPs. A topologically constrained relaxation theory is proposed by quantitatively correlating the relaxation time to the topologies of the SPCs, through the mean free space (Va) of tethered SPs in the cluster. The tethered SPs in SPCs are crowded by SPs of the melts to form the cage zones, and the cooperative diffusion of the tether SPs in the zones is required for the diffusive motion of SPCs. The cage zone serves as an entropic barrier for the diffusion of SP clusters, while its strength is determined by Va. Three characteristic modes can be confirmed: localized non-diffusive mode around critical Va, diffusive mode with Va deviating far from the critical value, and a sub-diffusive mode as an interlude between two limits. Our studies raise attention to the emergent physical properties of materials based on SPs via a topological design while opening new avenues for the design of soft structural materials.

Influence of Sn doping on particle cluster to rock-plate growth of nano-structured In2S3 thin films by nebulized spray pyrolysis technique

ABSTRACT The Nebulized Spray Pyrolysis (NSP) process has created Sn-doped In2S3 thin films for various molar percentages on micro glass substrates. The structural, optical, morphological, and electrical characteristics of the thin films have all been studied. A cubic phase had formed in each of the deposited films, according to an X-ray diffraction analysis. The average transmittance of the films ranged from 75 to 96%, while the bandgap energies for direct permitted transitions varied from 2.32 to 2.77 eV. The Scanning Electron Microscopy (SEM) images showed the rock-plate type nanoparticles grown over the surface of the glass plates. The Hall effect study revealed the n-type conductivity and with a 3 mol% Sn-doped In2S3 thin film exhibited a carrier concentration of 17.36 × 1018 cm−3 with the lowest resistance of 21.6 Ω-cm.

Phase diagram of generalized totally asymmetric simple exclusion process on an open chain: Liggett-like boundary conditions.

The totally asymmetric simple exclusion process with generalized update is a version of the discrete time totally asymmetric exclusion process with an additional interparticle interaction that controls the degree of particle clustering. Though the model was shown to be integrable on the ring and on the infinite lattice, on the open chain it was studied mainly numerically, while no analytic results existed even for its phase diagram. In this paper, we introduce boundary conditions associated with the infinite translation invariant stationary states of the model, which allow us to obtain the exact phase diagram analytically. We discuss the phase diagram in detail and confirm the analytic predictions by extensive numerical simulations.

A Dual-Particle Approach for Incompressible SPH Fluids

Tensile instability is one of the major obstacles to particle methods in fluid simulation, which would cause particles to clump in pairs under tension and prevent fluid simulation to generate small-scale thin features. To address this issue, previous particle methods either use a background pressure or a finite difference scheme to alleviate the particle clustering artifacts, yet still fail to produce small-scale thin features in free-surface flows. In this article, we propose a dual-particle approach for simulating incompressible fluids. Our approach involves incorporating supplementary virtual particles designed to capture and store particle pressures. These pressure samples undergo systematic redistribution at each time step, grounded in the initial positions of the fluid particles. By doing so, we effectively reduce tensile instability in standard SPH by narrowing down the unstable regions for particles experiencing tensile stress. As a result, we can accurately simulate free-surface flows with rich small-scale thin features, such as droplets, streamlines, and sheets, as demonstrated by experimental results.