Physics Open最新文献

{"title":"Activity concentration levels of natural radionuclides in soils of Anambra State, South-east Nigeria","authors":"Charles C. Ajaero ,&nbsp;Christian N. Madu ,&nbsp;Chukwuebuka C. Okafor ,&nbsp;Valentine E. Nnadi ,&nbsp;Festus A. Otunomo","doi":"10.1016/j.physo.2025.100361","DOIUrl":"10.1016/j.physo.2025.100361","url":null,"abstract":"<div><div>Much focus has not been paid to mapping of radionuclides in sedimentary formation in Nigeria. Thus, the relevance of this study which measured (mapped) the activity levels of radionuclides in the soils of Anambra State, Nigeria. Anambra State underlain by a younger sedimentary formation was chosen, as radionuclides levels in soils of older, consolidated sedimentary rocks and Basement complex rocks in Nigeria have been studied. The study measured radionuclides in soils of a predominantly sedimentary geologic formations much under-studied in Nigeria, and assessed how seasonal changes influences natural radionuclides levels in soil. The study was conducted for the dry and wet seasons of 2022. The study area, Anambra, was stratified into two geological formations, and twenty sampling points used. The major study objective is to determine the activity level of the radionuclides (U-238, Th-232, K-40, Ra-226) in the soil and; determine whether there is variation between the seasons (dry and wet). Our results show that there were variations in the levels of radionuclides (U-238, Th-232, K-40, Ra-226) between the dry and wet seasons based on the geologic formation. The levels of the radionuclides are generally higher in dry season than the wet season (U-238, Th-232, K-40, Ra-226). This was attributed to lack of moisture, which dampens gamma radiation. The study also showed that the levels of U-238 and Th-232 were significantly higher than their respective UNSCEAR (2000) population weighted averages in Ayamelum (Imo Shale), while they were significantly lower in the other locations- Orumba North (Imo Shale), Anambra East and Aguata (Nanka Shale). The levels of Ra-226 levels were significantly higher than UNSCEAR (2000) population weighted averages in all the locations. However, the levels of K-40 in all the locations were significantly lower than the population weighted averages. The study results also showed that statistically, the levels of U-238, Th-232 and Ra-226 in the soils varied between the two seasons (wet and dry). However, there was no statistically significant difference in the level of K-40 between the two seasons. The result finding therefore implies that season influences the levels of U-238, Th-232 and Ra-226 in the soils. Environmental factors may also be influencing the significant variations in radionuclides levels (U-238 and Th-232) in soils at different locations of the study area underlain by the same geologic formation.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100361"},"PeriodicalIF":1.4,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning Calabi–Yau three-folds, four-folds, and five-folds","authors":"Kaniba Mady Keita ,&nbsp;Younouss Hamèye Dicko","doi":"10.1016/j.physo.2025.100360","DOIUrl":"10.1016/j.physo.2025.100360","url":null,"abstract":"<div><div>In this manuscript, we demonstrate, using several regression techniques, that the remaining independent Hodge numbers of complete intersection Calabi–Yau four-folds and five-folds can be machine learned from <span><math><msup><mrow><mi>h</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup></math></span> and <span><math><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn><mo>,</mo><mn>1</mn></mrow></msup></math></span>. Consequently, we combine the Hodge numbers <span><math><msup><mrow><mi>h</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup></math></span> and <span><math><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn><mo>,</mo><mn>1</mn></mrow></msup></math></span> from the complete intersection Calabi-Yau three-folds, four-folds, and five-folds into a single dataset. We then implement various classification algorithms on this dataset. For example, Gaussian process and naive Bayes classifiers both achieve 100% accuracy in binary classification between three-folds and four-folds. Using the Support Vector Machine (SVM) algorithm, a special corner is identified in the Calabi–Yau four-fold landscape (characterized by <span><math><mrow><mn>15</mn><mo>≤</mo><msup><mrow><mi>h</mi></mrow><mrow><mn>1</mn><mo>,</mo><mn>1</mn></mrow></msup><mo>≤</mo><mn>30</mn></mrow></math></span> and <span><math><mrow><mn>95</mn><mo>≤</mo><msup><mrow><mi>h</mi></mrow><mrow><mn>2</mn><mo>,</mo><mn>1</mn></mrow></msup><mo>≤</mo><mn>100</mn></mrow></math></span>) during multiclass classification. Furthermore, the highest accuracy 1.00000, in classifying Calabi–Yau three-folds, four-folds, and five-folds is obtained using the naive Bayes classifier.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100360"},"PeriodicalIF":1.4,"publicationDate":"2025-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical treatment of Benjamin–Bona–Mahony–Burgers equation via integration of compact finite difference method with SSP-RK","authors":"Ravneet Kaur ,&nbsp;Geeta Arora ,&nbsp;Homan Emadifar","doi":"10.1016/j.physo.2025.100355","DOIUrl":"10.1016/j.physo.2025.100355","url":null,"abstract":"<div><div>In this work, a sixth-order compact finite difference method (CFDM6) is investigated to obtain the numerical solution of Benjamin–Bona–Mahony–Burgers equation (BBMBE). The compact finite-difference technique is used to approximate spatial derivatives at internal points and at the additional nodes. The time derivative is analyzed by a strong stability-preserving Runge–Kutta method of four stages and third order. The stability analysis of the proposed method is conducted to validate its stability. To validate the effectiveness and precision of the proposed method, the error norms <span><math><msub><mrow><mi>L</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>L</mi></mrow><mrow><mi>∞</mi></mrow></msub></math></span> are calculated for different illustrations. The analytical and numerical solutions from the literature are compared and presented in tables and graphs. The comparison shows that the computed values, are in good agreement, with the exact solution. This justifies the proficiency, precision, and computational implementation of the proposed method.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100355"},"PeriodicalIF":1.4,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, morphological, thermodynamic, and magnetic properties of Sm2Ni2O5: influence of co-precipitation vs sol-gel synthesis","authors":"Khethiwe Cele ,&nbsp;Sibusiso Nqayi ,&nbsp;Reddy Leelakrishna ,&nbsp;Buyisiwe Sondezi","doi":"10.1016/j.physo.2025.100358","DOIUrl":"10.1016/j.physo.2025.100358","url":null,"abstract":"<div><div>Crystalline Sm₂Ni₂O₅ nanoparticles (SNONPs) were synthesized via Co-precipitation and Sol-gel methods to examine how synthesis influences structural, morphological, thermodynamic, and magnetic properties. XRD confirmed both samples crystallized into an orthorhombic <em>Ima</em>2 structure after annealing at 800 °C for 6 h. SEM showed compact, smooth particles for Co-precipitated samples and brittle, fragmented ones for Sol-gel samples. EDS verified all expected elements with slight oxygen variation. Specific heat (0–300 K, 0.5 T) revealed distinct phase transitions: a 6 K anomaly indicating spin freezing in the Sm³⁺–O–Sm³⁺ framework; antiferromagnetic (AFM) ordering at T_N = 9 K from Ni²⁺–O–Ni²⁺ interactions; and a ferromagnetic (FM) transition at T_C = 43.6 K associated with Ni²⁺–O–Ni³⁺ sublattices. Above T_C, a paramagnetic (PM) phase emerged. The synthesis methods significantly affect crystallinity, governing magnetic and thermodynamic activities emphasizing SNONPs promise for spintronic and low-temperature magnetic applications.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100358"},"PeriodicalIF":1.4,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Different phase matching schemes of terahertz wave generation using periodic poled lithium niobate for real-world applications","authors":"Ugrasen Singh ,&nbsp;Abhinav Kumar ,&nbsp;Prashant Povel Dwivedi ,&nbsp;Ajay Mishra ,&nbsp;Nimish Dixit","doi":"10.1016/j.physo.2025.100357","DOIUrl":"10.1016/j.physo.2025.100357","url":null,"abstract":"<div><div>Terahertz (THz) wave generation through periodic poled lithium niobate (PPLN) has gained significant attention due to its potential applications in spectroscopy, imaging, communication, and security screening. Among various nonlinear optical materials, lithium niobate (LiNbO₃) has emerged as a promising medium for efficient THz generation due to strong nonlinear optical properties and wide transparency range. However, achieving efficient energy conversion requires effective phase matching to overcome phase velocity mismatch between the pump and the generated THz waves. Several phase-matching schemes have been explored to optimize THz generation. This review comprehensively discusses these schemes, analyzing their theoretical principles, experimental implementations, and practical applications. A comparative analyze is also provided to highlight the advantages and limitations of each approach. The presented literature aims to guide researchers in selecting appropriate phase-matching configurations for THz generation.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100357"},"PeriodicalIF":1.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical shifts in the Kα1,2 and Kβ1,3 X-ray emission spectra for halogen compounds of elements with atomic numbers ranging from 22 to 29 were measured using a wavelength-dispersive X-ray fluorescence spectrometer","authors":"E. Boydaş","doi":"10.1016/j.physo.2025.100316","DOIUrl":"10.1016/j.physo.2025.100316","url":null,"abstract":"<div><div>This study aimed to investigate the chemical shifts and full widths at half maximum (FWHM) of the Kα_1,2 and Kβ₁,₃ X-ray emission lines in selected halogen compounds of elements with atomic numbers ranging from 22 to 29. A Wavelength-Dispersive X-ray Fluorescence (WDXRF) spectrometer was employed for this analysis. The FWHM differences (ΔFWHM) of these emission lines were calculated by using the corresponding metallic element as a reference. The data revealed a clear pattern, showing larger chemical shifts for fluorine-containing compounds compared to chlorine-containing ones. In addition, the Kβ_1,3 lines generally show larger chemical shifts and wider full widths at half maximum (FWHM) compared to the Kα lines. The chemical shift also tends to increase as the number of coordinating ligand atoms rises.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100316"},"PeriodicalIF":1.4,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A physics-informed neural network framework for modeling rogue and breather solutions in conformable fractional nonlinear wave systems","authors":"Md. Towhiduzzaman ,&nbsp;Md. Abdul Al Mohit ,&nbsp;A.Z.M. Asaduzzaman","doi":"10.1016/j.physo.2025.100356","DOIUrl":"10.1016/j.physo.2025.100356","url":null,"abstract":"<div><div>This study presents a robust and generalized Physics-Informed Neural Network (PINN) framework for solving a class of conformable fractional nonlinear wave equations (CFNWEs). These equations are widely used in modeling complex wave dynamics in physical systems exhibiting memory and hereditary effects. By embedding the conformable fractional operator directly into the neural network architecture, the proposed model accurately captures localized nonlinear structures, including rogue waves and breather-type solutions. The framework employs a composite loss function integrating initial, boundary, and PDE residual constraints, optimized through a hybrid training strategy combining Adam and L-BFGS optimizers. Extensive numerical experiments validate the accuracy, physical consistency, and reproducibility of the proposed approach, demonstrating close agreement with analytical solutions. Moreover, the model exhibits robust performance under sparse and noisy data conditions, highlighting its potential for broad applications in wave dynamics, viscoelastic media, and nonlinear signal forecasting.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100356"},"PeriodicalIF":1.4,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational analysis of Hall current, radiation absorption and diffusion thermo effects on unsteady MHD rotating flow of Casson fluid through porous media with chemical reaction","authors":"G. Siddesh Babu ,&nbsp;R. Bhuvana Vijaya","doi":"10.1016/j.physo.2025.100351","DOIUrl":"10.1016/j.physo.2025.100351","url":null,"abstract":"<div><div>This study investigates the unsteady free-convective flow of an electrically conducting Casson fluid through a porous medium under the combined influences of Hall current, radiation absorption, Dufour effect, thermal radiation, Joule heating, viscous dissipation, and a homogeneous chemical reaction. The fluid motion is subjected to a uniform transverse magnetic field with variable permeability and oscillatory suction. The governing nonlinear partial differential equations for momentum, energy, and concentration are formulated and transformed into dimensionless form using appropriate similarity transformations. Closed-form analytical solutions are obtained through a perturbation method applied for small fluctuations in permeability. The analysis highlights the roles of key parameters—including the Hall parameter (m), magnetic parameter (M), Dufour number (Du), Prandtl number (Pr), Schmidt number (Sc), thermal and solutal Grashof numbers (<em>Gr</em>, Gm), chemical reaction rate (Kc), radiation parameter (Q₁), Joule heating parameter, viscous dissipation parameter, and rotation parameter (R)—on velocity, temperature, and concentration distributions. Engineering quantities such as skin friction, Nusselt number, and Sherwood number are also evaluated. The results show that Hall current enhances secondary flow but increases skin friction, while Dufour effect, radiation absorption, Joule heating, and viscous dissipation significantly elevate fluid temperature. Chemical reaction accelerates mass transfer, and rotation reduces magnetic damping, lowering frictional resistance. These findings provide valuable insights for optimizing heat and mass transfer in MHD energy systems, thermal processing operations, and chemically reactive porous-media environments.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"25 ","pages":"Article 100351"},"PeriodicalIF":1.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of conformal dual stop band frequency selective surface for microwave applications","authors":"Naveena Meka,&nbsp;Krishnan Shambavi","doi":"10.1016/j.physo.2025.100352","DOIUrl":"10.1016/j.physo.2025.100352","url":null,"abstract":"<div><div>A Conformal single layer ultra-thin dual band stop and bandpass Frequency Selective Surface (FSS) for microwave applications is proposed and experimentally evaluated in this letter. The proposed FSS uniquely combines dual passband functionality allowing the lower and upper WLAN spectra—with dual stopband performance that delivers wideband, wide-angle, and polarization-independent shielding for TE and TM polarizations. The proposed FSS consists of two Concentric Square Rings (CCSR) and two Convoluted Square Rings (CVSR) on a Rogers 3010 substrate of relative permittivity 10.2 and thickness 0.25 mm. The dimension of the unit cell is 0.1123<em>λo</em> × 0.1123<em>λo, λo</em> is the lowest resonant frequency. Planar and conformal FSS structures were systematically analyzed, fabricated, and characterized in an anechoic chamber to evaluate their passband performance and shielding effectiveness. The proposed FSS exhibits dual wide stopband characteristics ranging from 1.05 to 1.75 GHz, 3.4–4.6 GHz with shield effectiveness of 51 dB and 45 dB at 1.4 GHz, 4.06 GHz respectively. It also exhibits dual pass band response from 2.2 to 2.5 GHz and 5.4–5.9 GHz within band with insertion loss of 0.8 dB and 0.5 dB respectively. It also exhibits outstanding angular and polarization stability up to 80°. The close correlation between simulated and measured transmission responses validates the design's effectiveness in shielding the L band and 5G NR spectrum while maintaining high transmission in the lower and upper WLAN frequency bands.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"26 ","pages":"Article 100352"},"PeriodicalIF":1.4,"publicationDate":"2025-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145624952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of time-dependent MHD flow characteristics of Williamson nanofluid across a heated, permeable and inclined stretching sheet within a porous medium","authors":"Berihun Gizachew ,&nbsp;Hunegnaw Dessie ,&nbsp;Eshetu Haile ,&nbsp;Tadesse Walelign","doi":"10.1016/j.physo.2025.100349","DOIUrl":"10.1016/j.physo.2025.100349","url":null,"abstract":"<div><div>In this work, the unsteady magnetohydrodynamic (MHD) flow of a Williamson nanofluid via a heated, inclined stretching sheet that is permeable and imbedded in a porous media is examined. The present model includes simultaneously buoyancy forces, Joule heating, Dufour-Soret cross-diffusion, heat generation/absorption, an obliquely applied magnetic field and viscous dissipation. The governing nonlinear partial differential equations for momentum, energy and concentration are transformed into a system of coupled ordinary differential equations using similarity variables. For a semi-analytical analysis of this system, the robust Homotopy Analysis Method (HAM) is used in the Mathematica environment. Due to heightened Lorentz resistance, parametric investigation shows that raising the magnetic field inclination from 30° to 60° lowers the primary flow velocity by an estimated 8–19 %. The effect of species-driven energy diffusion is highlighted by the temperature distribution increasing by about 17 % as the Dufour number grows from 0.2 to 0.6. A significant thermo-diffusive mass transfer is demonstrated by the concentration profile escalating by over 25 % as the Soret effect increases from 0.1 to 0.5. On the other hand, the local Nusselt number is boosted by about 60 % when the Prandtl number is raised from 1.0 to 3.0, which greatly improves wall heat transfer. These revelations offer a useful theoretical foundation for maximizing transport efficiency in advanced heat control and material processing systems with porous and inclined configurations employed within intricate multi-physical situations.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"25 ","pages":"Article 100349"},"PeriodicalIF":1.4,"publicationDate":"2025-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145576067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}