Physica Scripta最新文献

{"title":"Modelling and optimization of epoxy-PMMA microcapsule synthesis parameter: A response surface methodology approach","authors":"Abdulafeez O. Akorede, Adetutu O Aliyu, A. A. Adebisi","doi":"10.1088/1402-4896/ad69e7","DOIUrl":"https://doi.org/10.1088/1402-4896/ad69e7","url":null,"abstract":"\u0000 The efficiency of self-healing microcapsule in restoring damages incurred by polymeric or composite materials is heavily dependent on modelling of encapsulation conditions to achieve optimized microcapsule with desired characteristics. This study modelled the effects of encapsulation conditions (core–shell ratio, agitation rate, and temperature) on the morphological, chemical, and thermal characteristics of epoxy-polymethylmethacrylate (epoxy-PMMA) microcapsules using response surface methodology (RSM). Epoxy-PMMA microcapsules were synthesized by encapsulating epoxy resin in polymethylmethacrylate (PMMA) at varied encapsulation conditions using solvent evaporation method. The morphology of the synthesized microcapsule using optical microscope (OP) revealed that the microcapsules are either mononuclear or irregular capsule types. The modelled effect showed that microcapsule percentage yield varied between 74.96 to 96.56%, was highly influenced by core–shell ratio and the effect of studied encapsulation conditions on percentage yield was best described by quadratic model. The core content of the microcapsules varied between 54.8 to 67.2%, observed to be highly influenced by both core–shell ratio and agitation rate which fit into linear model. The microcapsule average diameter was between 26 to 74 μm, highly influenced by agitation rate and fit linear model. Fourier transform infrared (FTIR) spectra of synthesized microcapsules revealed epoxy characteristic peak of C–O–C at 913 cm−1 and C–O-ph stretching at 1032 cm−1. C–O doublet of PMMA was observed at 1386 cm−1 and 1189 cm−1. Thermogravimetric analysis (TGA) of epoxy-PMMA microcapsule showed three stages of decomposition attributed to water evaporation, epoxy degradation, and PMMA shell degradation. Lastly, optimization process to achieve maximum yield, maximum core content and minimum capsule diameter was obtained with core–shell ratio of 1.5:3 and agitation rate of 1000 rpm at 40 °C. The synthesized epoxy-PMMA microcapsules exhibited chemical, thermal, morphological stability and the models can be optimized to achieve microcapsule with desired characteristics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"31 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923102","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":"Position dependent mass dissipative scalar field at finite temperature","authors":"marjan Jafari","doi":"10.1088/1402-4896/ad6dad","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6dad","url":null,"abstract":"\u0000 Position dependent mass dissipative scalar field is a theoretical framework that combines the concepts of position-dependent mass and dissipative systems in the context of scalar field theory. In this framework, the mass of the scalar field is allowed to vary with position, leading to interesting physical phenomena such as non-locality and non-Hermiticity. We consider a generalized classical Lagrangian for the system and by developing a theoretical formulation, quantized system canonically. In follow, two-point correlation functions of the system is obtained at finite temperature and Free energy of the system is calculated in terms of Matsubara frequencies. This research can provide insights into the behavior of particles and fields in non-uniform environments, and has potential applications in various fields of physics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"81 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922546","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":"Optimizing Mechanical Behavior in Polymer Bio-Composites Reinforced with Basalt, Graphene, and PP-g-MA","authors":"Hossein Taghipoor, Jaber Mirzaei","doi":"10.1088/1402-4896/ad6daa","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6daa","url":null,"abstract":"\u0000 This paper aims to investigate the mechanical properties of bio-composites reinforced with basalt natural fibers/nanographene in polypropylene by incorporating pp-g-ma compatibilizer. The study employs the Response Surface Method with the Behnken box approach to formulate a novel mathematical model for bio-composite behavior based on the parameters of basalt fiber weight percentage, nanographene weight percentage, and PP-g-MA weight percentage. Unlike previous studies, our work uniquely integrates basalt fibers and nanographene to enhance tensile, bending, and impact strengths, achieving a composite with optimal mechanical properties. The performance of the research samples was evaluated through tensile, bending, and impact tests, with the results substantiated using Field Emission Scanning Electron Microscopy images. The failure surface in these samples revealed that the central mechanism influencing the performance of the introduced bio-composite is the failure of the fibers and their separation, accompanied by the stretching of the fibers from the base material. Subsequently, multi-objective optimization was conducted with the aim of increasing tensile strength, bending strength, and impact strength while reducing the weight of the samples. A Pareto diagram is presented based on the design goals. The outcomes indicate that the bio-composite sample values in the most suitable state for three mechanical characteristics including, tensile, impact, and bending strength are equal to 28, 90, and 49 MPa, respectively. This innovative combination and optimization significantly improve performance metrics, demonstrated through extensive testing and multi-objective optimization, which reveals the bio-composite's superior mechanical characteristics.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"69 11","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922520","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":"Exact cosmological solutions of a Chaplygin Gas in Anisotropic Petrov Type D Spacetimes in Eddington-inspired-Born-Infeld gravity: Dark Energy Model","authors":"Guichard Djiodjo-Seugmo, Patenou Jean Baptiste, Calvin Tadmon","doi":"10.1088/1402-4896/ad6da4","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da4","url":null,"abstract":"\u0000 We consider a Petrov Type D physical metric g, an auxiliary metric q and a Chaplygin Gas of pressure P in Eddington-inspired-Born-Infeld theory. From the Eddington-inspired-Born-Infeld-Chaplygin Gas equations, we first derive a system of second order nonlinear ordinary differential equations. Then, by a suitable change of variables, we arrive at a system of first order linear ordinary differential equations for the non-vanishing components of the pressure P , the physical metric g and the auxiliary metric q. Thanks to the superposition method, we collect an analytical solution for the nonlinear system obtained, which allows to obtain new exact cosmological solutions for the model considered. By studying the Kretschmann invariant, we see a singularity exists at the origin of the cosmic time. By the Kruskal-like coordinates, we conclude that this solution is the counterpart of the Friedman-Lemaître Robertson-Walker spacetime in the Eddington-inspired-Born-Infeld theory. The Hubble and deceleration parameters in both directions of the physical metric g and the auxiliary metric q, as well as their behaviours over time, are also studied. The thermodynamic behaviour of the Chaplygin Gas model is investigated and, as a result, we show that the third-law of thermodynamics is verified. This means that the value of the entropy of the Chaplygin Gas in the perfect crystal state is zero at a temperature of zero Kelvin, which yields a determined value of the entropy and not an additive constant. Finally, we show that the solutions change asymptotically to the isotropic regime of expansion of Dark Energy. With this, we infer that the Chaplygin Gas can show a unified picture of Dark Energy and Dark Matter cooling during the expansion of the universe.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"5 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922069","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":"Triple Band Self-Decoupled MIMO Antenna Pair for 5G Communication","authors":"Parul Kansal, A. Mandpura, Narendra Kumar","doi":"10.1088/1402-4896/ad6da8","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da8","url":null,"abstract":"\u0000 A two port multiple input multiple output (MIMO) antenna with self-isolation is proposed for the application of fifth generation (5G) mobile phones. In this antenna, feeding ports that are inherently isolated across a bandwidth without the need for extra decoupling components directly excite the MIMO antenna. An approach involving the creation of common and differential modes utilizes a mode-cancellation technique to comprehensively understand the self-decoupling mechanism on a physical level. The proposed self-decoupled antenna pair exhibits about 22 dB isolation across the triple band 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz, respectively. According to the experimental findings, the proposed MIMO system may offer better than 22 dB isolation across all ports and a respectable level of overall gain 1.9 dBi, 3.77 dBi and 2.9 dBi across 2.58 GHz to 2.84 GHz, 3.4 GHz to 3.9 GHz and 4.3 GHz to 4.6 GHz. A suggested design method, with its advantages of self-decoupling, simple structure, high efficiency and triple band demonstrates amazing upcoming 5G highly integrated MIMO antennas for 5G devices.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"78 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922452","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 and Evaluation of β-Ga2O3 junction barrier Schottky diode with p-GaN Heterojunction","authors":"Phuc Hong Than, Tho Than, Yasushi Takaki","doi":"10.1088/1402-4896/ad6da2","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da2","url":null,"abstract":"\u0000 A novel design for a junction barrier Schottky (JBS) diode based on a p-GaN/n-Ga2O3 heterojunction is proposed, exhibiting superior static characteristics and a higher breakdown capability compared to the traditional Ga2O3 Schottky barrier diode (SBD). By utilizing wide-bandgap p-type GaN, the β-Ga2O3 JBS diodes demonstrate a turn-on voltage (Von) of approximately 0.8 V. Moreover, a breakdown voltage (Vbr) of 880 V and a specific on-resistance (Ron,sp) of 3.96 mΩ·cm2 are achieved, resulting in a Baliga’s figure of merit (BFOM) of approximately 0.2 GW/cm2. A forward current density of 465 A/cm2 at a forward voltage drop of 3 V is attained. The simulated reverse leakage current density remains low at 9.0 mA/cm2 at 800 V. Floating field rings, in conjunction with junction termination extension (JTE), were utilized as edge termination methods to attain a high breakdown voltage. The impact of β-Ga2O3 periodic fin width fluctuations on the electrical characteristics of JBS was investigated. Due to the enhanced sidewall depletion effect caused by p-type GaN, the forward current (IF) and reverse current (IR) decrease when the β-Ga2O3 periodic fin width decreases. The findings of this study indicate the remarkable promise of p-GaN/n-Ga2O3 JBS diodes for power device applications.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"4 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921586","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":"Non-Polynomial Spline Method for Computational study of ReactionDiffusion System","authors":"Mehboob Ul Haq, Sirajul Haq","doi":"10.1088/1402-4896/ad6da3","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da3","url":null,"abstract":"\u0000 This work addresses an efficient and new numerical technique utilizing non-polynomial splines to solve system of reaction diffusion equations (RDS). These system of equations arise in pattern formation of some special biological and chemical reactions. Different types of RDS are in the form of spirals, hexagons, stripes, and dissipative solitons. Chemical concentrations can travel as waves in reaction-diffusion systems, where wave like behaviour can be seen. The purpose of this research is to develop a stable, highly accurate and convergent scheme for the solution of aforementioned model. The method proposed in this paper utilizes forward difference for time discretization whereas for spatial discretization cubic non-polynomial spline is used to get approximate solution of the system under consideration. Furthermore, stability of the scheme is discussed via Von-Neumann criteria. Different orders of convergence is achieved for the scheme during a theoretical convergence test. Suggested method is tested for performance on various well known models such as, Brusselator, Schnakenberg, isothermal as well as linear models. Accuracy and efficiency of the scheme is checked in terms of relative error (ER) and L∞ norms for different time and space step sizes. The newly obtained results are analyzed and compared with those available in literature.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"49 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141922971","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":"Frequency-dependent capacitance and conductance characteristics and current transport mechanisms of Schottky diodes with TPA-IFA organic interfacial layer","authors":"Ş. Çavdar, Pınar Oruç, S. Eymur, Tugluoglu Nihat","doi":"10.1088/1402-4896/ad6dab","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6dab","url":null,"abstract":"\u0000 In this study, a Schottky barrier diode with an Al/TPA-IFA/p-Si structure was fabricated using spin coating and thermal evaporation methods. Using forward and reverse bias I–V measurement, we examined the key electrical characteristics of the Al/TPA-IFA/p-Si diode, including Φ_b, n, R_s, and N_ss; we also estimated V_D, N_A, E_F, 〖∆Φ〗_b, W_D, Φ_b and N_ss using C–V measurements under the different frequencies (10, 50, 100, 500 kHz, and 1 MHz) at room temperature. Using I–V data and the Thermionic Emission (TE) theory, basic electrical parameters such as ideality factor (n), and barrier height (Φ_b) values were computed as 3.01 and 0.716 eV. The fundamental diode parameters are highly frequency-dependent. It was also found that the series Resistance (R_s) values reduced with increasing frequency, but the barrier height (Φ_b) and the width of the depletion layer (W_D) increased. It was found that when frequency increased, the diode capacitance reduced for our new Schottky-type diode. The diode's potential conduction mechanisms were examined through the utilization of reverse \"ln\" I-V^0.5 and forward \"ln\" I-V graphs. The transport properties of Al/TPA-IFA/p-Si diode are primarily governed by ohmic conduction, Space Charge Limited Current (SCLC), and Trap Charge Limited Current (TCLC) mechanisms at low, moderate, and high voltages, respectively. It was concluded that the Poole-Frenkel Emission (PFE) mechanism was dominant for the Al/TPA-IFA/p-Si diode. Ultimately, the findings confirmed that the TPA-IFA-based diode could be obtained for the electronic application.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"48 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923698","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":"Noise-induced transport in a periodic square-well potential","authors":"Ronald Benjamin","doi":"10.1088/1402-4896/ad6da9","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da9","url":null,"abstract":"\u0000 We investigate a thermal ratchet based on a Brownian particle in a spatially periodic square-well potential driven by a time-dependent square-wave signal. In this model, we rock the Brownian particle between two square-well potentials tilted in opposite directions to induce a net current. Employing Stratonovich’s formula and an independent approach using suitable boundary conditions and a normalization condition, we obtain an exact expression for the current in the adiabatic limit, and we observe that there are optimal values of various parameters at which the current can be maximized. In several parameter regimes, our simple non-linear model displays a behavior distinct from some other models of a rocked ratchet. For example, a reversal in the current direction is observed as the square-wave signal's amplitude or the thermal bath's temperature is varied. However, under similar conditions, no such current reversal was seen in the case of a periodically rocked Brownian motor in a sawtooth or a smooth potential. Furthermore, unlike the latter type of rocked Brownian motors, the square-well model yields zero current in the deterministic limit, as thermal energy is indispensable for the functioning of the motor.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"58 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923489","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":"Obtained Berry phase and cyclotron mass of Bi2Se3 topological insulator thin film through weak anti-localization and Shubnikov-de Haas oscillation studies","authors":"N. Kander, Bikash Gajar, Sajib Biswas, Shubhadip Moulick, A. K. Das","doi":"10.1088/1402-4896/ad6da6","DOIUrl":"https://doi.org/10.1088/1402-4896/ad6da6","url":null,"abstract":"\u0000 Bi-based binary alloys have drawn enormous attention in modern condensed matter research for their novel topological property. Here, we have explored the quantum-transport properties of a 100nm Bi2Se3 topological insulator thin film grown by an indigenously developed electron-beam-evaporator through co-deposition technique. A detailed study about the structural, elemental, and morphological analysis has been presented through the GI-XRD, Raman spectroscopy, XPS, EDX, SEM, and AFM characterization. Finally, we have investigated the angle and temperature-dependent magneto-conductance properties of our deposited films, which indicate the surface-electron dominated quantum-transport has occurred. Interestingly, our Bi2Se3 film exhibits 2D weak anti-localization and Subnikov-de Hass oscillation features. From which some novel topological parameters are explored, such as, Berry phase (β), phase-coherence-length (lϕ), Fermi velocity (vF), wave vector (kF), Dingle temperature (TD), quantum mobility (μq), and cyclotron mass (mc). The estimated β = 0.7π and mc = 0.17me, indicate that the topologically protected massless Dirac particles can be achieved in this kind of system.","PeriodicalId":503429,"journal":{"name":"Physica Scripta","volume":"54 29","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923983","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}