Brazilian Journal of Physics最新文献

{"title":"Comments of Non-linear Numerical Analysis of Van der Pol Oscillator Coupled","authors":"Gabriella de O. M. Silva,&nbsp;Mauricio A. Ribeiro,&nbsp;Jeferson J. de Lima,&nbsp;Angelo M. Tusset,&nbsp;Marcus Varanis,&nbsp;Jose M. Balthazar,&nbsp;Clivaldo de Oliveira","doi":"10.1007/s13538-025-01755-4","DOIUrl":"10.1007/s13538-025-01755-4","url":null,"abstract":"<div><p>In this work, we investigated the behavior of basins of attraction and the nonlinear dynamics of a system of two coupled Van der Pol oscillators considering the action of an external force on one of the oscillators. Thus, we performed the parametric sweep and identified the screening in some basins with the uncertainty exponent and entropy basins of attraction. With these quantities, we were able to observe the possible fractality in the basins of attraction and thus establish the set of parameters that can alter the behavior of the initial conditions that are used in the coupled system. Another analysis was the nonlinear dynamics exploring the parameter space with the maximum Lyapunov exponent and thus establish a diagnosis of the regions that may possibly have chaotic behavior. Such results are confirmed with the phase maps, Poincaré maps, and the bifurcation diagram. These analyses corroborate future work such as the proposal of control techniques for the suppression of chaos in these established regions.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740929","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":"Application of the Tantawy Technique for Modeling Fractional Ion-Acoustic Waves in Electronegative Plasmas having Cairns Distributed-Electrons, Part (I): Fractional KdV Solitary Waves","authors":"Samir A. El-Tantawy,&nbsp;Sahibzada I. H. Bacha,&nbsp;Muhammad Khalid,&nbsp;Weaam Alhejaili","doi":"10.1007/s13538-025-01741-w","DOIUrl":"10.1007/s13538-025-01741-w","url":null,"abstract":"<div><p>This work examines both non-fractional and fractional ion-acoustic solitary waves (IASWs) in non-Maxwellian unmagnetized electronegative plasmas (ENPs) consisting of inertial positive and negative ions, as well as inertialess electrons adhering to the Cairns distribution. Our study comprises two primary objectives: the first objective is to utilize the reductive perturbation technique (RPT) to derive an evolutionary wave equation, specifically the quadratic nonlinearity planar Korteweg-de Vries (KdV) equation, which governs the propagation of solitary waves (SWs) in the current model. The secondary objective of this study, which is the core of the subject due to its novelty and importance, is to utilize the “Tantawy technique” for analyzing the fractional planar KdV (FKdV) equation and construct high accuracy and more stable approximations to deeply understand the characteristics of fractional KdV solitary waves (SWs) in the current model. Also, the Laplace new iterative approach (LNIM) is utilized to examine the FKdV equation and derive analytical approximations for the fractional SWs. Subsequently, the results are compared with those produced by the Tantawy technique to assess the effectiveness of each method. Additionally, the absolute error of the generated approximations using the two proposed techniques is quantitatively assessed, followed by comparing these results to evaluate the accuracy, efficiency, stability, fast computations, and low-cost computations of the Tantawy technique relative to the LNIM. The effect of plasma parameters like ion mass ratio, nonthermal, negative ion concentration, and fractional parameters on the characteristics of the KdV–SW profile is numerically investigated. The present investigation could be helpful to in space and astrophysical plasma systems.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740927","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":"Study of the New Mg2H3X (X = Br, Cl) Compounds: Hydrogen Storage Applications","authors":"S. Idrissi,&nbsp;A. Jabar,&nbsp;L. Bahmad","doi":"10.1007/s13538-025-01760-7","DOIUrl":"10.1007/s13538-025-01760-7","url":null,"abstract":"<div><p>This work tackles the structural and electronic features of the tetragonal compounds Mg₂H₃X (X = Br, Cl) using LSDA + mBJ within the framework of density functional theory (DFT). For Mg₂H₃Cl structural optimization gave a₀ = 3.894 Å, c₀ = 7.745 Å and a₀ = 3.870 Å, c₀ = 7.839 Å for Mg₂H₃Br. Differences of ionic radii are the reasons for explaining the changes of lattice parameters for these compounds. Mg₂H₃Br and Mg₂H₃Cl were found to have semiconducting properties with indirect band gaps of 1.374 eV and 1.755 eV, respectively. Their small band gaps suggest possible use in optoelectronic devices. These results indicate that Mg₂H₃Br may be suitable for low energy applications such as infrared detectors, while Mg₂H₃Cl may be useful in high energy applications such as photovoltaics. The calculated hydrogen gravimetric densities for Mg₂H₃Br and Mg₂H₃Cl are 2.300 wt% and 3.470 wt%, respectively. This indicates Mg₂H₃Cl has higher hydrogen storage capacity than Mg₂H₃Br. The results of the total and partial density of states are analyzed and these results can help understand how the constituent atoms shape the electronic structure. Moreover, the optical features of these compounds highlight their importance for hydrogen storage, electronic devices, and sophisticated optoelectronic materials. This information is important for understanding the prospects of developing advanced technologies based on Mg₂H₃Br and Mg₂H₃Cl.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740928","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":"Chromium Oxide Nanoparticles via Green Synthesis: Investigating Photocatalytic and Antimicrobial Properties Using Molecular Docking and Hirshfeld Surface Analysis","authors":"R. Gowsalya,&nbsp;P. Raji,&nbsp;M. Sivasankari","doi":"10.1007/s13538-025-01750-9","DOIUrl":"10.1007/s13538-025-01750-9","url":null,"abstract":"<div><p>A facile strategy was used for the synthesis of chromium oxide nanoparticles using leaf extract of <i>Tinospora cordifolia</i> via sol–gel auto combustion method and its photocatalytic performance was observed. The green synthesized Cr₂O₃ nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), EDAX, UV–Vis spectroscopy, transmission electron microscopy (TEM), selected area electron diffraction (SAED), and photoluminescence (PL). XRD pattern confirmed the purity of Cr₂O₃ nanoparticles. The SEM images showed porosity of Cr₂O₃ NPs. The band gap, as determined using UV–visible spectra, was measured to be 3.41 eV. TEM images revealed the crystalline shape and size of the nanoparticles. The PL spectra showed the emission peak at around 465 nm. In this study, inter-molecular interactions were examined using Hirshfeld surface analysis. The green synthesized Cr₂O₃ nanoparticles exhibit photodegradation efficiency up to 89.74% against malachite green dye after 25 min of UV irradiation. This investigation assessed the antimicrobial properties of Cr₂O₃ nanoparticles synthesized via a green route using <i>Tinospora cordifolia</i> leaf extract. The results revealed significant antibacterial activity against a panel of microorganisms, including Gram-positive <i>Staphylococcus</i> sp., <i>Bacillus</i> sp., and Gram-negative bacteria (<i>Klebsiella</i> sp.,<i> E</i>. <i>coli</i>), as well as potent antifungal activity against <i>Aspergillus niger</i>. Further, the interaction of Cr₂O₃ with key protein targets, FtsZ and DHFR, was evaluated using Autodock Vina. The molecular docking results indicated a strong binding affinity of Cr₂O₃ to the active sites of both FtsZ and DHFR proteins, with a docking score of − 2.66 and − 2.84, respectively.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143735432","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":"Enhanced Sensitivity for the Detection of Tuberculosis Based on Optical Biosensor at Terahertz Band Spectrum","authors":"Md.Golam Sadeque,&nbsp;Md.Sumon Ali,&nbsp;Ahsan Habib Shakil,&nbsp;Md. Safiul Islam,&nbsp;Mahmoud M. A. Eid,&nbsp;Ahmed Nabih Zaki Rashed,&nbsp;A. H. M. Iftekharul Ferdous","doi":"10.1007/s13538-025-01751-8","DOIUrl":"10.1007/s13538-025-01751-8","url":null,"abstract":"<div><p>Tuberculosis still remains a significant worldwide public health hazard, mostly due to insufficient political will to allocate resources for its elimination, unlike the response to diseases such as COVID-19. It has the highest fatality rate in one particular infection, higher than the other. In this study, we propose a hollow-core photonic crystal fiber (PCF) sensor optimized for tuberculosis detection in the terahertz (THz) spectrum. The sensor features an octagonal core with strategically placed air holes, enhancing light confinement and interaction with tuberculosis-infected blood samples. Using finite element method (FEM)-based simulations in COMSOL Multiphysics 5.6, we evaluated key performance parameters, including relative sensitivity (RS), confinement loss (CL), effective material loss (EML), effective area (EA), and numerical aperture (NA). The presented study provides the construction of a PhCs fiber sensor featuring a sensitive, uncomplicated core designed for the detection of tuberculosis at terahertz frequencies. This sensor can precisely identify TB bacteria in each strain and successfully differentiate among them. The new indicators have a high RS of 98.29% and lower overall losses of 3.30 × 10−1 dB/m compared to older detectors that used PCF. The sensor under evaluation has a confinement loss of 4.65 × 10⁻¹³ dBm⁻¹, an extremely low EML of 0.33 dBm⁻¹, and a NA of 0.273. This sensor guarantees optimal sensitivity for the detection of tuberculosis. The physical architecture of this sensor is easy, facilitating its construction with modern manufacturing methods. The sensor is therefore ready to improve the detection and treatment of aggressive tissues.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s13538-025-01751-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143707174","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":"Generalized Breather, Solitons, Rogue Waves, and Lumps for Superconductivity and Drift Cyclotron Waves in Plasma","authors":"Farrukh Shehzad,&nbsp;Handi Zahed,&nbsp;Syed T. R. Rizvi,&nbsp;Sarfaraz Ahmed,&nbsp;S. Abdel-Khalek,&nbsp;Aly R. Seadawy","doi":"10.1007/s13538-025-01738-5","DOIUrl":"10.1007/s13538-025-01738-5","url":null,"abstract":"<div><p>The valuable properties of nonlinear waves have been newly exploited to allow an extensive range of applications with broad applications for the explanation of superconductivity and drift cyclotron waves in radially inhomogeneous plasma for coherent ion-cyclotron waves. We study the propagation of lump waves, rogue waves, lump periodic waves, AKM breather waves, lump one strip, and generalized breather waves as well as their interactions. These nonlinear waves have so many applications in real life for example; breathers have been observed in shallow water wave systems, where they manifest as localized water wave disturbances, and rogue waves discuss the Earth’s climate system and also study complex dynamics of ocean waves. Lump waves are the localized wave structures studied in plasma, which is important for understanding energy transport, wave-particle interactions, and stability in plasma systems. The study of nonlinear waves is crucial for understanding a wide range of natural phenomena, scientific knowledge, advancing technology in various fields like communications and information processing, medical applications, quantum mechanics, plasma physics and fusion research, and astrophysics.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698643","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":"XGBoost Predictions of Heat Generation in MHD Natural Convection of Hybrid Nanofluid in a Wavy Porous Cavity","authors":"Noura Alsedais,&nbsp;Mohamed Ahmed Mansour,&nbsp;Abdelraheem M. Aly","doi":"10.1007/s13538-025-01747-4","DOIUrl":"10.1007/s13538-025-01747-4","url":null,"abstract":"&lt;div&gt;&lt;p&gt;This study investigates the effects of heat generation and magnetic fields on natural convection in a wavy porous cavity filled with a hybrid nanofluid (Al₂O₃-Cu/water), using the hybrid finite volume method (FVM) and XGBoost model within the local thermal non-equilibrium (LTNE) framework. The cavity contains inner heaters with variable lengths, positions, and heat generation/absorption coefficients. The primary objective is to analyze the interplay of key parameters, including heat source length (&lt;span&gt;(B)&lt;/span&gt;), position (&lt;span&gt;(D)&lt;/span&gt;), solid volume fraction (&lt;span&gt;(phi)&lt;/span&gt;), porosity (&lt;span&gt;(varepsilon)&lt;/span&gt;), Hartmann number (&lt;span&gt;(Ha)&lt;/span&gt;), Rayleigh number (&lt;span&gt;(Ra)&lt;/span&gt;), and the heat generation/absorption coefficient (&lt;span&gt;(Q)&lt;/span&gt;). The results provide insights into optimizing heat and mass transfer characteristics under varying conditions, with potential applications in thermal management systems. The mathematical model incorporates the governing equations for continuity, momentum, and energy for the fluid and solid phases. The LTNE approach accounts for separate temperature fields for the fluid and solid, enabling a detailed analysis of the thermal behavior. The numerical simulations were performed using dimensionless formulations, allowing the study of a wide range of physical and geometric parameters. The cavity geometry includes a wavy right wall maintained at a cold temperature (&lt;span&gt;({T}_{c})&lt;/span&gt;) and a flat left wall with localized heat sources (&lt;span&gt;({T}_{h})&lt;/span&gt;). The findings reveal the significant influence of &lt;span&gt;(B)&lt;/span&gt;, &lt;span&gt;(D)&lt;/span&gt;, &lt;span&gt;(phi)&lt;/span&gt;, and &lt;span&gt;(Q)&lt;/span&gt; on the flow structure and thermal distribution. An increase in &lt;span&gt;(B)&lt;/span&gt; intensifies convective currents and enhances heat transfer efficiency, while the position of the heat source (&lt;span&gt;(D)&lt;/span&gt;) modulates the distribution of buoyancy forces. The addition of nanoparticles (&lt;span&gt;(phi)&lt;/span&gt;) improves the effective thermal conductivity of the hybrid nanofluid, enhancing both fluid and solid phase heat transfer. Positive values of &lt;span&gt;(Q)&lt;/span&gt; further amplify buoyancy-driven convection, resulting in higher Nusselt numbers (&lt;span&gt;(Nu)&lt;/span&gt;). The impact of porosity (&lt;span&gt;(varepsilon)&lt;/span&gt;) and Rayleigh number (&lt;span&gt;(Ra)&lt;/span&gt;) was also evaluated. Higher porosity values promote fluid permeability, facilitating stronger convective currents and more uniform temperature profiles. Similarly, increasing &lt;span&gt;(Ra)&lt;/span&gt; shifts the dominant heat transfer mechanism from conduction to convection, enhancing thermal mixing and efficiency. The Hartmann number (&lt;span&gt;(Ha)&lt;/span&gt;) was found to suppress convection due to magnetic damping effects, reducing heat transfer rates. However, this damping can be partially offset by the enhanced thermal conductivity from higher nanoparticle concentrations (&lt;span&gt;(phi)&lt;/span&gt;). AI-based models, specifically XGBoost, were employed to predict the Nusselt number f","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698642","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":"Integrated Dynamics of Eco-Epidemic Systems: Nonlinear Prey Refuge, Predator Exploitation, Fear Impact, and Infection Control","authors":"Md Sarijul Islam,&nbsp;Bapin Mondal,&nbsp;Sahabuddin Sarwardi","doi":"10.1007/s13538-025-01744-7","DOIUrl":"10.1007/s13538-025-01744-7","url":null,"abstract":"<div><p>The article investigates an eco-epidemic predator-prey model, where only the prey population becomes infected. Both the prey populations take nonlinear prey refuge with different coefficients to protect themselves from their predator. Fear of predators reduces the growth rate and activity of the prey population, which in turn reduces the rate of disease transmission. The model system incorporates treatment for infected individuals. After formulation of the model system, some preliminary results of the system are executed and followed by system’s points of equilibrium. We have calculated the basic reproduction number that holds a crucial role in determining the eradication of disease from the system. Analysis of the system’s bifurcation with respect to different crucial parameters is executed. By increasing the value of treatment parameters to a certain extent, it is found that the disease can be eradicated from the system. Further, Pontryagin’s maximum principal is used to optimize the disease control. Some numerical simulations illustrate and validate the obtained results.</p></div>","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688274","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":"Correction: Spin-Gapless Quaternary Heusler Alloys IrCoTiZ (Z = Si, Sn, Pb): Exploring New Opportunities in Spintronics, Optoelectronics, and Thermoelectrics","authors":"A. Khatar,&nbsp;B. Bouadjemi,&nbsp;M. Houari,&nbsp;M. Matougui,&nbsp;T. Lantri,&nbsp;K. Khelifa-Kerfa,&nbsp;S. Bentata,&nbsp;S. Haid,&nbsp;M. H. Cherif,&nbsp;A. Messaoudi,&nbsp;S. Mesbah","doi":"10.1007/s13538-025-01752-7","DOIUrl":"10.1007/s13538-025-01752-7","url":null,"abstract":"","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688459","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":"Correction: Combined Impacts of Self-Generated and Non-uniform Magnetic Fields on the Acceleration of Plasma Electrons","authors":"Mehdi Abedi-Varaki,&nbsp;Bahman Zohuri","doi":"10.1007/s13538-025-01756-3","DOIUrl":"10.1007/s13538-025-01756-3","url":null,"abstract":"","PeriodicalId":499,"journal":{"name":"Brazilian Journal of Physics","volume":"55 3","pages":""},"PeriodicalIF":1.5,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688460","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}