The European Physical Journal Plus最新文献

{"title":"Fractional space–time modeling of MHD mixed convection and entropy generation over a permeable moving surface","authors":"Oluwole Daniel Makinde,&nbsp;Waqar Ahmed Khan,&nbsp;Zafar Hayat Khan,&nbsp;Alexander Trounev","doi":"10.1140/epjp/s13360-026-07622-8","DOIUrl":"10.1140/epjp/s13360-026-07622-8","url":null,"abstract":"<div><p>This study presents a fractional space–time model for magnetohydrodynamic (MHD) mixed convection and entropy generation in boundary layer flow over a moving permeable surface. The governing momentum and energy equations are formulated using Caputo-type time- and space-fractional derivatives of orders <span>(0&lt;alpha le 1)</span> and <span>(0&lt;gamma le 1)</span>, allowing the incorporation of memory and nonlocal transport effects that cannot be captured by classical integer-order models. The influences of key parameters, including the magnetic field parameter (0 ≤ <span>(M le 3))</span>, Grashof number (0 ≤ Gr ≤ 5), Eckert number (0 ≤ <span>(text{Ec }le 1))</span>, Biot number (0.1 ≤ Bi ≤ 5), and surface suction/injection, are systematically examined. The resulting coupled nonlinear fractional partial differential equations are solved numerically using an Euler wavelet collocation method combined with an implicit finite difference scheme. The results show that increasing fractional orders significantly suppress velocity and temperature fields due to enhanced memory effects, leading to reduced heat transfer rates. Injection intensifies entropy generation by amplifying velocity and thermal gradients, whereas suction stabilizes the boundary layer and minimizes irreversibility. Strong magnetic fields increase entropy production through Joule dissipation while damping fluid motion. The proposed fractional framework provides deeper insight into irreversibility control and thermal optimization in MHD convection systems relevant to energy conversion, thermal management, and porous surface technologies.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Enhancing 6 MV X-ray shielding performance of concrete via tungsten carbide reinforcement: an experimental study","authors":"Hamza Tunç,&nbsp;Berna Oto,&nbsp;Mehmet Turkmenoglu,&nbsp;Taylan Tuğrul,&nbsp;Halime Erzen Yildiz","doi":"10.1140/epjp/s13360-026-07658-w","DOIUrl":"10.1140/epjp/s13360-026-07658-w","url":null,"abstract":"<div><p>This study experimentally investigates the radiation shielding performance of concrete composites in which conventional sand was partially replaced with tungsten carbide (WC) at weight fractions ranging from 0 to 20%. After a curing period of 28 days, photon transmission measurements were conducted using 6 MV X-ray beams generated by a medical linear accelerator, representing high-energy radiation conditions commonly encountered in clinical radiotherapy environments. Based on the measured dose values, key shielding parameters including the linear attenuation coefficient (μ), half-value thickness, and mean free path (mfp_X) were determined. In addition, photon interaction characteristics were analyzed through exposure buildup factor and energy absorption buildup factor calculations using the EpiXS code, while the fast neutron shielding capability of the composites was evaluated via the macroscopic neutron removal cross section (Σ_R). The experimental results indicate that the incorporation of tungsten carbide significantly enhances the density and radiation attenuation capability of the concrete matrix. Increasing WC content led to improved photon shielding efficiency and reduced penetration depth of high-energy X-rays. This study provides a simultaneous assessment of both photon and neutron shielding in WC-reinforced concretes, highlighting the influence of WC content on energy-dependent buildup factors and demonstrating an optimized mix design strategy for enhanced radiation protection. These findings demonstrate that tungsten carbide-reinforced concretes can serve as promising high-performance materials for radiation shielding applications in medical, nuclear, and accelerator-based facilities, addressing limitations in previous studies that focused on single radiation types or conventional concrete mixes.</p><h3>Graphical abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture><span>The alternative text for this image may have been generated using AI.</span></div></div></figure></div></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-026-07658-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Effects of matter with anisotropic pressure on the Fan–Wang regular black hole shadows","authors":"Yergali Kurmanov,&nbsp;Orlando Luongo,&nbsp;Daulet Berkimbayev,&nbsp;Kuantay Boshkayev,&nbsp;Talgar Konysbayev,&nbsp;Marco Muccino,&nbsp;Guldana Rabigulova,&nbsp;Ainur Urazalina,&nbsp;Ulpan Nurlanbek","doi":"10.1140/epjp/s13360-026-07660-2","DOIUrl":"10.1140/epjp/s13360-026-07660-2","url":null,"abstract":"<div><p>In this work, we investigate the consequences of an exotic fluid exhibiting negative radial and tangential pressures—thereby violating the Zel’dovich limit—on a regular solution that generalizes the Schwarzschild black hole. Specifically, we focus on the regular Fan–Wang spacetime and analyze how the presence of such a fluid modifies the black hole shadow images through negative equations of state for both pressure components. Although fundamentally different from quintessence, we consider constant radial and tangential state parameters to emulate, but not reproduce, the effects of dark energy. Furthermore, we explore the main properties of infalling spherical accretion flows and study how these state parameters influence the horizons, photosphere, and impact parameter of the Fan–Wang black hole.  We determine the black hole shadow by analyzing the null geodesics of massless test particles in the background spacetime, which serves as a reference geometry. The physical photon shadow is obtained using the effective metric induced by nonlinear electrodynamics. We examine the observed intensity under two spherical accretion scenarios in both geometries. Finally, we provide a physical interpretation of the role of negative pressures in our results and discuss possible extensions of this framework to the isotropic case.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Bifurcation-induced regime shift phenomenon in a tri-trophic food chain model with commensalistic prey","authors":"Debabrata Mandal,&nbsp;Sourav Kumar Sasmal","doi":"10.1140/epjp/s13360-026-07670-0","DOIUrl":"10.1140/epjp/s13360-026-07670-0","url":null,"abstract":"<div><p>Regime shifts in ecological systems often arise from gradual or sudden transitions in ecological states that can occur by bifurcations in the underlying dynamical structure. This study examines how variability in significant system parameters triggers the regime shift phenomenon in a tri-trophic food chain model comprising a generalist predator and its two prey species, which engage in a commensalistic interaction. Analytical studies ensure boundedness, persistence, and system permanence, whereas bifurcation diagrams show how ecological parameter variations may shift regimes. Analytical and numerical results demonstrate that commensalistic interactions can substantially alter the bifurcation structure and can stimulate or inhibit significant shifts in ecological regimes, thereby influencing species coexistence and ecosystem resilience. A catastrophic shift has been identified, in which a minor alteration in the predator’s intraspecific competition rate unexpectedly lead one prey species to extinction via a saddle-node bifurcation. This study offers a thorough analytical framework for comprehending how bifurcation-driven regime shifts in intricate ecological networks are mediated by species interactions.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Measurements of efficiency, timing and response to irradiation for direct detection of charged particles with SiPMs","authors":"B. Sabiu,&nbsp;F. Carnesecchi,&nbsp;B. R. Achari,&nbsp;N. Agrawal,&nbsp;A. Alici,&nbsp;P. Antonioli,&nbsp;S. Arcelli,&nbsp;C. Baldanza,&nbsp;F. Bellini,&nbsp;S. Bufalino,&nbsp;D. Cavazza,&nbsp;L. Cifarelli,&nbsp;G. Clai,&nbsp;M. Colocci,&nbsp;S. Durando,&nbsp;F. Ercolessi,&nbsp;G. Fabbri,&nbsp;D. Falchieri,&nbsp;C. Ferrero,&nbsp;A. Ficorella,&nbsp;U. Follo,&nbsp;M. Garbini,&nbsp;S. Geminiani,&nbsp;G. Gioachin,&nbsp;A. Gola,&nbsp;D. Hatzifotiadou,&nbsp;A. Khuntia,&nbsp;I. Lax,&nbsp;M. Maestrelli,&nbsp;A. Margotti,&nbsp;G. Malfattore,&nbsp;R. Nania,&nbsp;F. Noferini,&nbsp;L. Parellada-Monreal,&nbsp;M. Penna,&nbsp;O. Pinazza,&nbsp;R. Preghenella,&nbsp;M. Razza,&nbsp;R. Ricci,&nbsp;L. Rignanese,&nbsp;A. Rivetti,&nbsp;G. Romanenko,&nbsp;N. Rubini,&nbsp;E. Rovati,&nbsp;E. Scapparone,&nbsp;G. Scioli,&nbsp;S. Strazzi,&nbsp;S. Tomassini,&nbsp;C. Veri,&nbsp;A. Zichichi","doi":"10.1140/epjp/s13360-026-07578-9","DOIUrl":"10.1140/epjp/s13360-026-07578-9","url":null,"abstract":"<div><p>In this paper, the efficiency of direct charged particle detection with different silicon photomultiplier (SiPM) sensors has been measured to be close to 100%. A time resolution of about 20 ps has also been confirmed for sensors with an active area of about 3<span>(times)</span>3 <span>(hbox {mm}^{text {2}})</span> and a single-cell pitch of area of 40<span>(times)</span>40 µ<span>(hbox {m}^{text {2}})</span>. In addition, the SiPM performance after irradiation, in terms of timing response and dark count rate, has been evaluated for sensors with a 1<span>(times)</span>1 <span>(hbox {mm}^{text {2}})</span> area, demonstrating that SiPMs can maintain excellent timing capabilities and a low dark count rate when an appropriate threshold is applied to the signal.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-026-07578-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Enhancing the intrinsic decoherence dynamics of quantum nonlocality for semiconductor quantum dot qubits: quantum steering, bell nonlocality and entanglement","authors":"A.-B. A. Mohamed,&nbsp;E. K. Jaradat,&nbsp;Ahmad N. Khedr,&nbsp;S. S. Alharbi","doi":"10.1140/epjp/s13360-026-07607-7","DOIUrl":"10.1140/epjp/s13360-026-07607-7","url":null,"abstract":"<div><p>In this study, we present a theoretical exploration of the intrinsic decoherence dynamics governing quantum correlations in a system of strongly coupled semiconductor quantum dots, supporting advancements in quantum computing and quantum communication. The study focuses on the evolution and interplay of two-qubit entanglement, quantum steering, and Bell non-locality. By systematically varying detuning, tunnel coupling, and dipole-dipole interaction strengths, we analyze their respective impacts on the system’s behavior. Our analysis confirms the fundamental hierarchy <span>(N(t) ge S(t) ge B(t))</span> across all physically relevant parameter spaces, with entanglement exhibiting superior temporal stability compared to the more fragile resources of Bell nonlocality and quantum steering. Specifically, we quantify how detuning affects measurement non-locality values and collapse timescales, revealing that steering undergoes sudden death at characteristically earlier times than entanglement–a vulnerability arising from its intermediate operational character in the correlation hierarchy. Furthermore, we evaluate the resilience of initial maximal non-local correlations under the influence of band energy, dipole-dipole interaction, and intrinsic decoherence. The physical parameters that optimize each class of correlation are identified, and we show that their evolution follows a monotonic dependence on the primary system parameters. This result highlights the significant impact of the quantum tunneling mechanism on the formation and persistence of correlations within quantum dot systems, thereby supporting their potential applications in quantum information processing and computation.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Probing kinetic freezeout properties in Au+Au collisions with a Tsallis blast wave analysis","authors":"Lei Yuan,&nbsp;Jian-Ning Han,&nbsp;Dong-Hai Zhang,&nbsp;Jihane Ben Slimane,&nbsp;Zoalnoon Ahmed Abeid Allah Saad","doi":"10.1140/epjp/s13360-026-07614-8","DOIUrl":"10.1140/epjp/s13360-026-07614-8","url":null,"abstract":"<div><p>The study of transverse momentum spectra is important for understanding the kinematics of high-energy heavy-ion collisions and the characteristics of particle production. In this paper, we performed the blast wave model with Tsallis statistics on the transverse momentum spectra of light flavor particles with strange and non-strange quark content species in different centralities of the Au+Au collisions at <span>(sqrt{s_{NN}}=54.4)</span> GeV. The relevant parameters include the kinetic freezeout temperature parameter, <i>T</i>, transverse flow velocity, <span>(beta _T)</span>, and the non-extensive parameter, <i>q</i>, are extracted. Besides, we calculated the mean transverse momentum (<span>(&lt;p_T&gt;)</span>). We found that the extracted parameters are interrelated and depend on the collision geometry, the amount of deposited energy, and the collision dynamics with changing centrality. Furthermore, all the extracted parameters change with mass of the particle, except the parameter <i>T</i> which shows that strange and non-strange particles freezeout separately due to different cross section of the reactions.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Progress study on BaAl₀.₁₅Fe₁₁.₈₅O₁₉ M-type hexaferrite nanoparticles for supercapacitor applications","authors":"Amina I. Ghoneim,&nbsp;Moustafa El-Tahawy,&nbsp;R. M. Muthukrishnan,&nbsp;Ahmed M. A. Henaish","doi":"10.1140/epjp/s13360-026-07597-6","DOIUrl":"10.1140/epjp/s13360-026-07597-6","url":null,"abstract":"<div><p>BaAl_0.15Fe_11.85O₁₉ M-type hexaferrite was prepared successfully through the chemical co-precipitation technique. The phase composition and crystal structure were investigated through X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), which confirmed the successful development of a single-phase M-type hexaferrite structure. Scanning electron microscopy (SEM) revealed that the particles exhibit a hexagonal platelet-like morphology. Room-temperature magnetic characterization was performed using a vibrating sample magnetometer (VSM), demonstrating a saturation magnetization (<i>M</i>_s) of 63 emu/g, a coercive field (<i>H</i>_c) of 2236 Gauss, and a remnant magnetization (<i>M</i>_r) of 30 emu/g. The optical properties of the BaAl_0.15Fe_11.85O₁₉ sample were investigated using UV–vis diffuse reflectance spectroscopy (DRS). The estimated bandgap energy values are 2.5 eV (<i>E</i>_gd) and 2.25 eV (<i>E</i>_gi). The electrochemical capacitance of the prepared sample was evaluated to determine its energy storage performance. The results showed that the specific capacitance of the BaAl_0.15Fe_11.85O₁₉ electrode materials reached its optimum value of 301.5 F/g at 10 mV/s. According to their high specific capacitance, these electrode materials are promising candidates for supercapacitor applications.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Floquet dynamics of helical edge states in 2D topological insulators under longitudinal periodic fields","authors":"Farshad Azizi,&nbsp;Sobhan Sharafkhani,&nbsp;Hossein Bahramiyan","doi":"10.1140/epjp/s13360-026-07679-5","DOIUrl":"10.1140/epjp/s13360-026-07679-5","url":null,"abstract":"<div><p>Topological insulators (TIs) are pivotal in condensed matter physics and hold significant relevance for chemical sciences through material design and tunability due to their protected helical edge states, robust against static perturbations. The dynamics under time-dependent electromagnetic drives, particularly longitudinal periodic ones preserving time-reversal symmetry, remain actively explored. This work develops a theoretical framework for helical edge states in 2D TIs under such drives, deriving time-dependent dispersions, photon-assisted scattering amplitudes, and oscillatory conductance. Using a tight-binding model with Floquet theory and Green’s functions, incorporating the periodic drive via Peierls substitution, we provide explicit derivations of matrices, phases, and expansions. Results reveal conductance oscillations from dynamic Aharonov–Bohm-like phases and quasienergy shifts in finite systems, with propagation asymmetries preventing complete cancellation. Validated by numerical simulations in five figures, including Floquet quasienergy spectrum, and compared with established computational and experimental works. This contributes to the understanding of driven quantum transport, offering insights for HgTe microwave experiments in chemically synthesized HgTe/CdTe quantum wells and tunable spintronics. The approach addresses finite-size effects and observability amid disorder and temperature, distinguishing it from prior studies on infinite systems or symmetry-breaking drives. Furthermore, we discuss chemical tunability and relevance to chemically synthesized materials, including structure–property relations and chemically controlled topological behavior.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147738107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Statistical properties of the gravitational force through ordering statistics","authors":"Constantin Payerne,&nbsp;Vincent Rossetto","doi":"10.1140/epjp/s13360-026-07649-x","DOIUrl":"10.1140/epjp/s13360-026-07649-x","url":null,"abstract":"<div><p>We investigate the statistical distribution of Newtonian gravitational forces acting on a test particle embedded in an infinite, homogeneous, and uncorrelated random gas of point masses. Using order statistics, we derive the probability density functions of distances to the <i>n-</i>th nearest neighbors in arbitrary spatial dimensions and analyze their contributions to the total gravitational force. We show that, in three dimensions, the formally divergent variance of the Holtsmark probability density function arises entirely from the first nearest neighbor, while contributions from more distant neighbors remain finite. Our results provide a clear decomposition of local versus distant contributions to the gravitational forces exerted on a test particle, and explore the dominant role of nearest neighbors in the divergence of the Holtsmark distribution’s variance.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"141 4","pages":""},"PeriodicalIF":2.9,"publicationDate":"2026-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147737364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}