The European Physical Journal E最新文献

{"title":"Free-interface convective mixing in porous media: 2D and 3D numerical simulations","authors":"Happiness Imuetinyan,&nbsp;Stefano Musacchio,&nbsp;Fabrizio Croccolo,&nbsp;Guido Boffetta","doi":"10.1140/epje/s10189-026-00566-y","DOIUrl":"10.1140/epje/s10189-026-00566-y","url":null,"abstract":"<p>We investigate convective mixing in porous media in the presence of a free interface separating two miscible fluids initially arranged in a stable configuration. This problem is motivated by the dynamics of supercritical <span>(hbox {CO}_{2})</span> overlying a brine-saturated porous medium, as well as analogous laboratory experiments. Diffusion of the lighter upper layer into the denser lower layer results in a layer with a density greater than that of the denser lower layer, which then induces an unstable stratification that triggers convection. Using high-resolution direct numerical simulations, we analyse the system dynamics in both two- and three-dimensional geometries and for different diffusivities. Our results show that in 2D the process is faster, with dissolution fluxes about <span>(15%)</span> higher than in 3D. Convective plumes deform the initially flat interface, creating an iso-concentration surface whose vertical extent increases over time. These findings highlight the need for caution when extrapolating two-dimensional results to three-dimensional applications.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147324306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of MHD rayleigh–taylor instability in a walter’s B fluid with thermal and mass diffusion effects","authors":"Km Priya Bharti,&nbsp;Mukesh Kumar Awasthi,&nbsp;Atul Kumar Shukla,&nbsp;Gopal Datt","doi":"10.1140/epje/s10189-026-00563-1","DOIUrl":"10.1140/epje/s10189-026-00563-1","url":null,"abstract":"<div><p>An analytical and numerical investigation of Rayleigh<b>–</b>Taylor instability has been carried out within a planner configuration under the influence of a vertically imposed magnetic field, through viscous potential flow theory. The instability is examined for the configuration in which a Walter’s B viscoelastic fluid overlies a Newtonian viscous fluid embedded in a porous medium, with simultaneous heat and mass transfer permitted across the interface. The dispersion relation between perturbation growth rate and wave number is established via normal mode analysis. This relation is investigated using the Newton<b>–</b>Raphson method, which facilitates the identification of the influence of various non-dimensional physical parameters, determining whether they suppress or amplify the perturbation growth. The study reveals that a vertically oriented magnetic field and an increased porosity of the medium enhance the amplification of perturbations, while an increased thermal flux across the interface counteracts this tendency, thereby diminishing the growth of instability.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div><div><p>Rayleigh–Taylor instability is analyzed for a Walters’ B viscoelastic fluid overlying a Newtonian viscous fluid in a porous medium under a vertically imposed magnetic field with simultaneous heat and mass transfer. A dispersion relation is derived using viscous potential flow theory and solved numerically via the Newton–Raphson method. Results show that magnetic field strength and medium porosity enhance perturbation growth, whereas increased thermal flux stabilizes the interface</p></div></div></figure></div></div>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147324278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometric confinement reveals scale-free velocity correlations in epithelial cell monolayer","authors":"Guillaume Duprez,&nbsp;Mélina Durande,&nbsp;François Graner,&nbsp;Hélène Delanoë-Ayari","doi":"10.1140/epje/s10189-026-00564-0","DOIUrl":"10.1140/epje/s10189-026-00564-0","url":null,"abstract":"<p>Collective cell flows are a hallmark of tissue dynamics in development, wound healing, and various diseases. Here, we investigate how the size, shape, topology and rigidity of patterned substrate influence the organization of flows and mechanical fields in an epithelial MDCK cell monolayer at several time and space scales. Using micropatterned substrates with and without free front (a strip and a closed racetrack), we show that confinement and obstacles induce spatial heterogeneities in velocity and force fields, leading to the emergence of domains, waves, and long-range correlations. We show that spatial velocity correlations are scale-free, following a power law whose exponent evolves as the monolayer matures. This challenges the notion of a single intrinsic correlation length. We also show that in absence of free front, spontaneous collective motions are stronger on soft than on hard substrate. Our findings provide new insights into the rheology of epithelial tissues and the interplay between mechanics and collective migration.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147300710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupled interplays between proliferation and hydrodynamic interactions modulate the transport of chemotactic entities","authors":"Kuipou William,&nbsp;Belobo Belobo Didier","doi":"10.1140/epje/s10189-026-00559-x","DOIUrl":"10.1140/epje/s10189-026-00559-x","url":null,"abstract":"<p>This study investigates the stability properties of two interacting chemotactic populations by introducing an extended mathematical model that simultaneously incorporates competitive hydrodynamic interactions and kinetic growth dynamics. Using a standard plane wave analysis, we demonstrate that the interplay between hydrodynamic and kinetic interactions governs the system’s stability. Specifically, the system remains stable for long wave vectors when strong-strong kinetic interactions are coupled with either weak-weak or strong-weak hydrodynamic interactions. Conversely, stability for short wave vectors is achieved when weak-weak kinetic interactions are paired with similar hydrodynamic configurations. To explore localized dynamics, we perform a generalized linear stability analysis using spatially localized functions. This reveals the emergence of rapid oscillations that modulate both stationary and non-stationary wave patterns. Modulated structures are sensitive to the choice of the envelope function: waves initiated with Gaussian-type profiles are more prone to instability than those generated with secant-type functions. Numerical simulations further illustrate the formation of stable non-uniformly distributed structures. The generalized perturbation framework presented here highlights the delicate balance between hydrodynamics and competitive interactions occurring within biological tissues during invasion, showcasing new insights into collective transport, pattern formation, and strategies for organ repair.</p><p>The dynamics of localized unstable modes at short wave vectors indicate that instability grows with self-induced hydrodynamic flows in the <span>(WW_p-SW_h)</span> regime. In other words, self-induced flows act to extend instability across the parameter domain. In addition, instability remains localized along kinetic competition parameters, highlighting the extensive role played by those factors to contain the instability when self-induced hydrodynamics flows become dominant in the medium</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147281790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrophilicity controls thermodiffusion in alkylammonium chlorides","authors":"Binny A. Rudani,&nbsp;Hartmut Kriegs,&nbsp;Simone Wiegand","doi":"10.1140/epje/s10189-026-00561-3","DOIUrl":"10.1140/epje/s10189-026-00561-3","url":null,"abstract":"<p>In this study, we examine the Soret effect of ammonium chloride (<span>(hbox {NH}_4)</span>Cl) and its alkyl-substituted derivatives: dimethylammonium chloride (DMACl), ethylammonium chloride (EACl), and trimethylammonium chloride (TMACl) in aqueous solution using infrared thermal diffusion forced Rayleigh scattering. The Soret coefficient, <span>(S_{mathrm T})</span>, increases systematically with alkyl substitution, following the trend <span>(hbox {NH}_4)</span>Cl <span>(ll )</span> DMACl &lt; EACl <span>(ll )</span> TMACl, while hydrophilicity decreases correspondingly. Across the investigated temperature range (<span>(15!-!45^circ )</span>C) and concentrations (1–4 mol/kg), <span>(S_{mathrm T})</span> increases with both temperature and the degree of alkyl substitution. However, the concentration dependence varies among the salts. DMACl, EACl, and TMACl exhibit decreasing <span>(S_{mathrm T})</span> with increasing concentration and are predominantly thermophobic; TMACl remains thermophobic under all conditions. In contrast, <span>(hbox {NH}_4)</span>Cl shows a non-monotonic concentration dependence above <span>(35~^circ )</span>C and is largely thermophilic. We discuss the origin of this minimum at elevated temperatures in relation to other aqueous salt systems that exhibit non-monotonic behavior of <span>(S_{mathrm T})</span> with respect to concentration. Overall, each additional alkyl substitution decreases the temperature sensitivity of the Soret coefficient, <span>(Delta S_{mathrm T}(Delta T))</span>, consistent with reduced solute hydrophilicity. Furthermore, we observe a clear correlation between the thermal diffusion coefficient and the thermal expansion coefficient in these aqueous electrolyte solutions. This is consistent with the trends reported for nonpolar organic mixtures and aqueous solutions of non-ionic solutes. These findings highlight thermodiffusion as a sensitive probe for understanding how hydrophilicity and ion-specific interactions govern molecular transport in aqueous environments.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12932385/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147281763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental Determination of the Dielectric Constant of Micellar Hydration Layer via Localized Surface Plasmon Resonance of Gold Nanoparticles","authors":"Elizete J. Patel,&nbsp;Julia L. M. Carneiro,&nbsp;Rozane F. Turchiello,&nbsp;Sergio L. Gómez","doi":"10.1140/epje/s10189-026-00558-y","DOIUrl":"10.1140/epje/s10189-026-00558-y","url":null,"abstract":"<p>The localized surface plasmon resonance (LSPR) of plasmonic nanoparticles can be used both for measuring the dielectric constant in which they are dispersed and for determining changes in the structure of the medium around them. In this work, we explored the shift in the LSPR of gold nanoparticles (AuNPs), obtaining the out-of-plane dielectric constant of the hydration layer of nanoparticles dispersed in aqueous solutions of sodium dodecyl sulfate for concentrations below and above the critical micelle concentration. A reduction is observed, which is due to a soft confinement between the nanoparticle and the micelles. The confinement favors the in-plane alignment of the water’s molecular dipoles, hindering a rotation out-of-plane and reducing the tendency to align with an external electric field, i.e., diminishing the medium’s polarization.</p><p>The short penetration depth of the localized surface plasmon in a gold nanoparticle enables probing of the dielectric constant of a nanometer-scale layer near the interface, where water molecules are more highly organized than in bulk water. The presence of micelles further intensifies the structuring of water near the nanoparticle interface.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12923398/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146257030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification of 2D colloidal assemblies in images: a threshold processing method versus machine learning","authors":"Ludia T. Khusainova,&nbsp;Konstantin S. Kolegov","doi":"10.1140/epje/s10189-026-00560-4","DOIUrl":"10.1140/epje/s10189-026-00560-4","url":null,"abstract":"<p>This paper is devoted to the problem of identification of colloidal assemblies using the example of two-dimensional coatings (monolayer assemblies). Colloidal systems are used in various fields of science and technology, for example, in applications for photonics and functional coatings. The physical properties depend on the morphology of the structure of the colloidal assemblies. Therefore, effective identification of particle assemblies is of interest. The following classification is considered here: isolated particles, dimers, chains and clusters. We have studied and compared two identification methods: image threshold analysis using the OpenCV library and machine learning using the YOLOv8 model as an example. The features and current results of training a neural network model on a dataset specially prepared for this work are described. A comparative characteristic of both methods is given. The best result was shown by the machine learning method (97% accuracy). The threshold processing method showed an accuracy of about 67%. The developed algorithms and software modules may be useful to scientists and engineers working in the field of materials science in the future.</p><p>Automatic recognition of particle configurations</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 3","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146211896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Graph theoretical characterization and QSPR modeling of aluminum and magnesium hydroxide networks through integrated face degree topological indices","authors":"Micheal Arockiaraj,&nbsp;Thirsha Rajendran,&nbsp;Arul Jeya Shalini,&nbsp;Krishnan Balasubramanian","doi":"10.1140/epje/s10189-025-00554-8","DOIUrl":"10.1140/epje/s10189-025-00554-8","url":null,"abstract":"<p>Aluminum hydroxide (gibbsite) and magnesium hydroxide (brucite) rank among the most prevalent hydroxide minerals and function as structural prototypes for diverse layered materials, including phyllosilicates, layered double hydroxides, and emerging two-dimensional halides. An exciting feature of these materials is their novel electronic and spintronic functionalities. Gibbsite adopts a dioctahedral framework with one-third of its octahedral sites vacant and stabilized by hydrogen bonding, whereas brucite forms a fully occupied trioctahedral lattice bound by van der Waals interactions. Such structural differences critically influence their stability, reactivity, and functional versatility. The present study develops a topological framework by employing classical degree-based indices, along with face degree and degree-sum variants, to characterize their network structures and compute their properties. We employ univariate and bivariate regression models in conjunction with the quantitative structure–property relationship (QSPR) approach to predict physicochemical properties of aluminum and magnesium hydroxide configurations, such as <span>(log )</span> <i>P</i> (base 10), molecular weight, and molar refractivity. The integrated methodology demonstrates improved structural discrimination and predictive reliability, highlighting the utility of topological indices in QSPR analysis.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 1-2","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146197320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A molecular dynamics simulation of thermalization of crystalline lattice with harmonic interaction","authors":"Zhenwei Yao","doi":"10.1140/epje/s10189-026-00562-2","DOIUrl":"10.1140/epje/s10189-026-00562-2","url":null,"abstract":"<p>Understanding the realization of thermal equilibrium through the thermalization process in a many-body system is a fundamental and complex scientific question, bridging thermodynamics and classical dynamics and connecting to a host of physical phenomena, such as mechanical instabilities in a thermal environment. In this work, based on the harmonic lattice model, we investigate the thermalization process in both velocity and coordinate spaces, by examining microscopic dynamics on the atomic level. We show the distinct relaxation rates of the transverse and longitudinal components of the velocity, reveal the power law governing the nonlinear proliferation of dominant frequencies, and observe the concurrent rapid proliferations of frequencies and topological defects. We also show that the lattice system’s persistent out-of-plane deformations exhibit two-stage fluctuation behaviors, characterized by distinct power laws of fractional exponents and associated with the broken up-down symmetry. This work demonstrates the rich dynamics underlying the thermalization process and advances our understanding on the dynamical adaptations of many-body systems to external disturbances.</p>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 1-2","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146193813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Micro-mechanical approaches to characterize tip growth: Insights into root hair elasto-viscoplastic properties","authors":"Thomas Alline,&nbsp;Léa Cascaro,&nbsp;David Pereira,&nbsp;Atef Asnacios","doi":"10.1140/epje/s10189-025-00546-8","DOIUrl":"10.1140/epje/s10189-025-00546-8","url":null,"abstract":"<div><p>Root hairs are outgrowths of the epidermal cells of plant roots. They increase the root's exchange surface with the soil and provide it with good anchorage in the soil. Root hairs are an emblematic model of apical growth, a process also used by yeasts and hyphae to invade their environment. From a mechanical perspective, the root hair is considered as an elastic cylinder under pressure, closed by a dome that behaves like a yield fluid. We introduce here two innovative mechanical setups and protocols to characterize the mechanical properties of single growing root hairs in <i>Arabidopsis thaliana</i>. In the first setup, root hairs grow against an elastic obstacle until buckling. By measuring the critical buckling force, we determine the surface modulus and estimate the Young’s modulus of the cell wall, which aligns with previous measurements. Using a 1D elasto-viscoplastic model of root hair growth, we assess the excess pressure beyond the yield threshold (the driver of tip growth) and estimate the axial stiffness of the root hair, reflecting its elastic resistance to compression. For the second protocol, we designed a setup where a single root hair grows against a cantilever with variable stiffness, a technique adapted from our earlier work on rigidity sensing by animal cells. This method provides an independent estimate of the root hair's axial stiffness, confirming our initial findings and suggesting that this stiffness primarily involves tip compression and depends mainly on turgor pressure, at least within the low deformation regime explored.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":790,"journal":{"name":"The European Physical Journal E","volume":"49 1-2","pages":""},"PeriodicalIF":2.2,"publicationDate":"2026-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12886323/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146140684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}