Physics Open最新文献

{"title":"Structural, optoelectronic, mechanical and thermodynamic properties of AgMgX3(X= Cl, Br): A first principles study","authors":"Md Ashikur Rahman,&nbsp;Md Jobayer Hassan,&nbsp;Jerin Haider,&nbsp;Md Meskat Ali,&nbsp;Md Mahmudul Hasan,&nbsp;Md Alamgir Badsha","doi":"10.1016/j.physo.2025.100288","DOIUrl":"10.1016/j.physo.2025.100288","url":null,"abstract":"<div><div>Maintaining a contamination-free environment is crucial for researchers developing industrial products. The lead-free perovskite compounds, AgMgX₃ (X = Cl, Br), have utilized density functional theory (DFT) to assess their properties. The stability of these compounds is confirmed by the Goldsmith tolerance factor and negative formation energy. For AgMgCl₃, the calculated indirect band gap values are 1.655 eV and 1.228 eV, while AgMgBr₃ shows band gap values of 0.889 eV and 0.453 eV, as determined by the GGA-PBE and LDA-CAPZ functionals, respectively. In addition, the hybrid functional HSE06 yields a band gap of 1.80 eV for AgMgCl₃ and 1.035 eV for AgMgBr₃. Both materials exhibit p-type semiconductor behavior. Moreover, these compounds demonstrate a high absorption coefficient, good optical conductivity, and low reflectivity within the visible spectral range, making them promising candidates for various applications. Their mechanical stability and ductility support the fabrication of thin films for use in heterostructure devices. The imaginary phonon frequency indicates dynamical instability, and ab initio molecular dynamics (AIMD) reaffirm their elastic stability. Both perovskites exhibit anharmonic behavior at higher temperatures below melting point and high Debye temperatures suggest strong thermal stability. Consequently, the properties of these materials may pave the way for new optoelectronic applications.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100288"},"PeriodicalIF":0.0,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144490960","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":"Optical OTFS waveform PAPR analysis for high order modulation employing CNN, DNN, and AE machine learning algorithms under a variety of channel scenarios","authors":"Arun Kumar ,&nbsp;Nishant Gaur ,&nbsp;Aziz Nanthaamornphong","doi":"10.1016/j.physo.2025.100284","DOIUrl":"10.1016/j.physo.2025.100284","url":null,"abstract":"<div><div>Optical orthogonal time–frequency space (OTFS) modulation is a future technique for optical wireless communication with high mobility. Nevertheless, the high peak-to-average power ratio (PAPR) of OTFS modulation severely degrades the system performance, particularly in the case of high-order modulation formats. This paper proposes an algorithm for machine-learning (ML)-based PAPR reduction dedicated to optical OTFS under varying channel conditions, such as turbulence and multipath fading. The proposed method utilizes deep learning models to maximize signal processing and suppress peak-power variations, while ensuring signal integrity. The simulations result prove that the proposed method attains a PAPR reduction of about 4 dB and 3.8 dB for 256-QAM and 2.2 dB and 1.6 dB for 64-QAM under a Rayleigh and Rician channel at a Complementary Cumulative Distribution Function (CCDF) of 10-5, better than conventional PAPR reduction methods. Power Spectral Density (PSD) analysis verifies that ML-based techniques, such as deep neural networks (DNN), convolutional neural networks (CNN), and autoencoders (AE), are spectrally efficient with negligible out-of-band radiation of -1070 and -1470 for 256QAM with diverse channel conditions. Moreover, Bit Error Rate (BER) performance tests demonstrate an SNR improvement of 8.2 dB and 3.9 at a BER of 10-5, guaranteeing error-free data transmission for diverse mobility scenarios. Furthermore, the proposed methods are compared with partial transmission schemes (PTS), selective mapping (SLM), tone reservation (TR), companding, clipping, and filtering (C&amp;F). The numerical results emphasize the capability of ML to improve PAPR performance without PSD and BER performance. The results are significant for future optical wireless networks, where high data rates must be sustained and nonlinear distortion minimized.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100284"},"PeriodicalIF":0.0,"publicationDate":"2025-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144480113","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 comparative artificial neural networks for Schwarzschild black hole (SBH) radius","authors":"Khalil Ur Rehman ,&nbsp;Wasfi Shatanawi ,&nbsp;Weam G. Alharbi","doi":"10.1016/j.physo.2025.100287","DOIUrl":"10.1016/j.physo.2025.100287","url":null,"abstract":"<div><div>It is consensus among researchers that the data for the black holes is complicated and extremely non-linear in nature. Therefore, it remains a challenging task for them to predict the key characteristics of concerned black holes accurately. The present work offers artificial neural networks assistance in the context of a choice of training functions for the prediction of astrophysical phenomena like the event horizon and radius of black holes. To be more specific, we considered the Schwarzschild black hole as the simplest solution of Einstein's field equations. The Schwarzschild radius and masses are chosen in the last and first layers of the neural networks model, respectively. Two various training functions namely Levenberg-Marquardt training algorithm (LMTA) and Scaled Conjugate Gradient training algorithms (SCGTA) are used. We have observed that the LMTA achieved significantly lower error rates, suggesting a better fit and stronger learning capabilities from the solar masses of black holes. Furthermore, the close alignment between the ANN-predicted and actual Schwarzschild black hole radius demonstrates the LMTA model holds the ability to generalize effectively across unseen masses of black holes.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100287"},"PeriodicalIF":0.0,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144297259","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":"Conservation relationship bridging entropy and information","authors":"Stoyan C. Russev","doi":"10.1016/j.physo.2025.100285","DOIUrl":"10.1016/j.physo.2025.100285","url":null,"abstract":"<div><div>Entropy and information are interconnected concepts fundamental to physics and information theory with reflections in different fields like biology, computer science, cosmology, information technology, even social science and law. However, a generally accepted quantitative link between them is still missing. This study addresses the fundamental relationship between physical entropy and information. It is shown here that there is a simple and universal conservation relationship between physical entropy and appropriately interpreted information entropy. As an illustration of its application, it is demonstrated that Landauer's lower bound on entropy change can be directly derived from this relationship.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100285"},"PeriodicalIF":0.0,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330301","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":"Enhanced electrical and magnetic properties of Gd-doped Ni-Zn ferrites for energy storage applications","authors":"P. Shanthakumari ,&nbsp;Naveena Gadwala ,&nbsp;K. Sathi Reddy ,&nbsp;Sathish Boddolla","doi":"10.1016/j.physo.2025.100286","DOIUrl":"10.1016/j.physo.2025.100286","url":null,"abstract":"<div><div>Gadolinium (Gd³⁺)-substituted Ni₀.₈Zn₀.₂Gd_xFe_2-xO₄ spinel ferrites (x = 0.00, 0.05, 0.10, 0.15, 0.20) were synthesized using the citrate-gel auto-combustion technique. X-ray diffraction confirmed the formation of a cubic spinel structure, with an increase in average crystallite size upon Gd³⁺ substitution, while the lattice parameter showed a decreasing trend. Field emission scanning electron microscopy revealed agglomerated particles with homogeneous dispersion, and a reduction in grain size due to doping. Energy dispersive X-ray spectroscopy confirmed the presence of the expected elements. Fourier-transform infrared spectroscopy identified tetrahedral and octahedral vibrational bonds (ν₁ and ν₂), from which the force constants (K_T and K_O) were determined. Electrical measurements, including dielectric constant, dielectric loss, and AC conductivity, were conducted at room temperature, showing a decreasing trend with increasing Gd³⁺ content. Magnetic characterization indicated a reduction in saturation magnetization and an increase in coercivity. The incorporation of Gd³⁺ into Ni-Zn ferrites notably influenced both the electrical and magnetic properties of the synthesized materials. Which are suitable for communication and energy storage systems.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100286"},"PeriodicalIF":0.0,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144272023","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":"DFT computational modeling studies of electronic and magnetic features of transition metal doped ZnTe","authors":"M. Amzaoued ,&nbsp;S. Zriouel ,&nbsp;M. Mabrouki","doi":"10.1016/j.physo.2025.100275","DOIUrl":"10.1016/j.physo.2025.100275","url":null,"abstract":"<div><div>This paper presents a first-principles investigation of the electronic structure and magnetism of dilute magnetic semiconductors (DMSs), with a particular focus on transition-metal-doped <span><math><mrow><mi>Z</mi><mi>n</mi><mi>T</mi><mi>e</mi></mrow></math></span> systems relevant to spintronic applications. Using density functional theory within the local-density approximation, we explore how magnetic impurities influence the electronic states and magnetic interactions in <span><math><mrow><mi>Z</mi><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub><mi>T</mi><msub><mrow><mi>M</mi></mrow><mrow><mi>x</mi></mrow></msub><mi>T</mi><mi>e</mi></mrow></math></span> where <span><math><mrow><mi>T</mi><mi>M</mi><mo>=</mo><mn>3</mn><mi>d</mi></mrow></math></span> transition metal atoms namely <span><math><mi>V</mi></math></span>, <span><math><mrow><mi>C</mi><mi>r</mi></mrow></math></span>, <span><math><mrow><mi>M</mi><mi>n</mi></mrow></math></span>, and <span><math><mrow><mi>C</mi><mi>o</mi></mrow></math></span> and <span><math><mi>x</mi></math></span> is the fractional concentration of <span><math><mrow><mi>T</mi><mi>M</mi></mrow></math></span>. The total and partial density of states, as well as the calculated Curie temperatures <span><math><mrow><mo>(</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>C</mi></mrow></msub><mo>)</mo></mrow></math></span>, are carefully analyzed and discussed. Our results demonstrate that the electronic configuration of the dopant atoms plays a crucial role in stabilizing ferromagnetic ordering, revealing distinct trends across different transition-metal elements <span><math><mrow><mo>(</mo><mi>T</mi><mi>M</mi><mo>)</mo></mrow></math></span>. The emergence of half-metallic ferromagnetism in <span><math><mrow><mi>Z</mi><msub><mrow><mi>n</mi></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub><mi>T</mi><msub><mrow><mi>M</mi></mrow><mrow><mi>x</mi></mrow></msub><mi>T</mi><mi>e</mi></mrow></math></span> is interpreted in terms of the <span><math><mrow><mi>T</mi><mi>M</mi><mo>−</mo><mn>3</mn><mi>d</mi></mrow></math></span> electronic states. Using a mean-field theoretical approach, we estimate the Curie temperatures for various DMS systems, obtaining values that align well with available experimental data. These findings provide valuable insights into the underlying mechanisms of magnetism in DMSs and support the development of a comprehensive model for understanding chemical trends, ultimately guiding the design of high<span><math><mrow><mo>−</mo><msub><mrow><mi>T</mi></mrow><mrow><mi>C</mi></mrow></msub></mrow></math></span> materials for future spintronic technologies.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100275"},"PeriodicalIF":0.0,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144330300","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 numerical model and comparative investigation of a thermoelectric generator with novel profile designs","authors":"Tan Nguyen Tien ,&nbsp;Duc Tran Duy ,&nbsp;Vinh Nguyen Duy ,&nbsp;Dien Vu Minh ,&nbsp;Hoa Binh Pham ,&nbsp;Quang Khong Vu","doi":"10.1016/j.physo.2025.100283","DOIUrl":"10.1016/j.physo.2025.100283","url":null,"abstract":"<div><div>Thermoelectric generators (TEGs), known as devices, convert waste heat to potential electricity. TEGs feature simple assembly, quiet work, non-exhaust, and stability based on thermodynamics together with Seebeck, Peltier, and Thomson effects. However, the performance of TEG is not high because the thermoelectric conversion inside TEG faces low efficiency. Typically, the cooling exchanger mounted in TEG partly affects the thermoelectric conversion. This paper offers three alternatives to the cooling exchanger based on a commercial model with different channel profiles. All are simulated and evaluated as thermodynamic and mass factors for TEG performance, such as temperature, pressure, and occupied solid volume. Then, two optimal alternatives based on three prior alternatives are analyzed, as well as properties and non-symmetric effects on TEG performance. Therefore, the results show that the different temperatures between the central fluid of the cooling exchanger and the top plate plane of TEG in optimized alternatives are larger than in the commercial model (i.e., 185 K and 183 K for optimal alternatives and 167 K for the commercial model with 5 L/min of mass flow rate inlet).</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100283"},"PeriodicalIF":0.0,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144178590","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":"Revisiting a Reynolds experiment: head loss in non-fully developed, unsteady flow","authors":"H.S. Tang,&nbsp;Priata Saha","doi":"10.1016/j.physo.2025.100274","DOIUrl":"10.1016/j.physo.2025.100274","url":null,"abstract":"<div><div>Head loss plays a central role in fluid flows. The head loss in fully developed, steady flows is relatively clear, and its calculation has matured and been applied widely in practical problems with success. However, there is a lack of understanding and effective methods to estimate head loss in non-fully developed, unsteady flows. This paper revisits a Reynolds experiment, which, unlike the original experiment by Reynolds in 1883, adopts unsteady flows (with non-constant water heads) exhibiting negative inertia heads. It discusses their head loss in a tube section where the flows have not fully developed. It shows that the head loss is higher in unsteady flows than in steady flows, with the difference being about two orders of magnitude greater than the inertia head. Also, it illustrates that the Darcy-Weisbach equation cannot replicate the measurement data for the head loss in both steady and unsteady, non-fully developed flows. Moreover, the paper presents an expression for head loss in such unsteady flows in terms of steady-flow head loss and inertia head.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100274"},"PeriodicalIF":0.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144242829","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":"3D modelling of hydrogen embrittlement in austenitic stainless steel and nickel-based superalloy: Physical metallurgy aspects on hydrogen entrapment","authors":"Behzad Sadeghi ,&nbsp;Pasquale Cavaliere ,&nbsp;Alicja Stanislawska","doi":"10.1016/j.physo.2025.100253","DOIUrl":"10.1016/j.physo.2025.100253","url":null,"abstract":"<div><div>This study explores the intricate relationship between hydrogen and the microstructural elements of austenitic stainless steels and nickel-based superalloys, with particular focus on their propensity for hydrogen embrittlement (HE). Utilizing sophisticated simulation tools within the ANSYS framework, we have developed an in-depth 3D model that intricately portrays the subtle hydrogen diffusion dynamics as they interact with microstructural features, including grain boundaries, dislocations, precipitates, and the lattice framework. This model illuminates the pivotal roles these microstructural interfaces play in the transportation and trapping of hydrogen and their contribution to the vulnerability of these alloys to HE. Our findings reveal that dislocations serve as a critical factor in dictating hydrogen diffusion behavior, which offer alternative pathways significantly influencing hydrogen distribution throughout the microstructure. The behavior of these dislocations is found to be highly temperature-sensitive, exhibiting distinct properties under varying thermal conditions and over extended durations. The simulation results are consistent with established models of hydrogen behavior in metallic systems and confirm that both microstructural nuances and temperature have a significant influence on hydrogen diffusion, which is in line with theoretical expectations. The insights gleaned from this research will assist in the engineering of materials that are more resilient to the deleterious effects of hydrogen penetration, thereby enhancing the safety and dependability of components operating in hydrogen-intensive environments.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100253"},"PeriodicalIF":0.0,"publicationDate":"2025-05-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144212932","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":"Effects of applied mechanical stress on the properties of the boundary between circular domains in a cylindrical magnetic wire","authors":"Ján Ziman,&nbsp;Jozef Onufer,&nbsp;Peter Duranka,&nbsp;Mária Kladivová,&nbsp;Peter Vrábel","doi":"10.1016/j.physo.2025.100279","DOIUrl":"10.1016/j.physo.2025.100279","url":null,"abstract":"<div><div>The paper presents the study of the motion of an individual domain wall in a cylindrical amorphous wire with negative magnetostriction and helical anisotropy induced by the simultaneous application of torsional and tensile mechanical stresses. The non-zero axial component of the magnetization made it possible to monitor the motion of the domain wall by means of suitably wound pick-up coils. Experimental results showed that the wall mobility increases significantly with the application of torsional stress. For a model of a planar domain wall, the calculated eddy currents damping of the wall motion is too strong to explain this increase. Presence of a non-zero axial component of the magnetization can cause the transformation of a planar wall to a deformed wall, axial length of which increases with the applied torsion. It can be expected that the damping of the propagating deformed wall is lower and thus its mobility increases.</div></div>","PeriodicalId":36067,"journal":{"name":"Physics Open","volume":"24 ","pages":"Article 100279"},"PeriodicalIF":0.0,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144099430","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}