Chaos Solitons & Fractals最新文献

{"title":"Effect of complex vortices generated by asymmetrically distributed induced charges on fluid flow and mass transfer in pressure driven micromixers","authors":"Shuai Yuan ,&nbsp;Tao Peng ,&nbsp;Xiaodong Liu","doi":"10.1016/j.chaos.2025.116373","DOIUrl":"10.1016/j.chaos.2025.116373","url":null,"abstract":"<div><div>Microscale electric field-induced vortical structures, arising from spatial accumulation of induced charges, demonstrate significant potential for augmenting mixing performance in low Reynolds number (<em>Re</em>) laminar flows. This investigation establishes a computational framework incorporating an asymmetric conductive plate with hybrid linear-curvilinear edges to systematically elucidate the coupling mechanisms between inhomogeneous charge distributions, complex vortex generation, and pressure-driven molecular transport. Our findings reveal that under balanced pressure-driven flow (PDF) and induced-charge electroosmotic flow (EOF), expanding the polarization area promotes bilateral charge accumulation along curvilinear boundaries, creating localized electric field minima that suppress interfacial slip velocity and mixing efficiency. In contrast, linear edges exhibit maximum slip velocities, generating vortex pairs with enhanced convection capacity. Notably, plate reorientation and increased curvature radius amplify surface electric field asymmetry, achieving superior mass transfer through either expanded vortex perturbation domains or intensified rotational intensity. When PDF dominates EOF by 25-fold, the weakened charge heterogeneity minimally stimulates vortex development, rendering interfacial perturbation the primary mixing driver. This work advances fundamental understanding of asymmetric charge-polarization dynamics in microscale flow manipulation, offering critical insights for designing active micromixers.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116373"},"PeriodicalIF":5.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143746960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multifractal analysis of temperature in Europe: Climate change effect","authors":"Borko Stosic ,&nbsp;Tatijana Stosic ,&nbsp;Ivana Tošić ,&nbsp;Vladimir Djurdjević","doi":"10.1016/j.chaos.2025.116386","DOIUrl":"10.1016/j.chaos.2025.116386","url":null,"abstract":"<div><div>We investigated multifractality of temporal series of daily mean air temperature anomalies over the entire European continent by applying the method Multifractal detrended fluctuation analysis (MFDFA) on high resolution E-OBSv26.0e dataset. The spatial resolution is 0.1⁰ which corresponds to 120,866 grid cells, and the time span of daily temperature series is from 1961 to 2020, which permits to compare two climate periods (1961–1990 and 1991–2020) and evaluate the impact of climate change. For each grid cell and each of the two periods we calculated the multifractal spectrum <span><math><mi>f</mi><mfenced><mi>α</mi></mfenced></math></span> which contains the information about specific properties of temperature series: persistence (described by the position of the maximum of the spectrum <span><math><msub><mi>α</mi><mn>0</mn></msub></math></span>), strength of multifractality (described by the spectrum width <span><math><mi>W</mi></math></span>) and the contribution of large/small fluctuations (described by the spectrum skew parameter <span><math><mi>r</mi><mo>)</mo><mo>.</mo></math></span>We found that in both periods temperature series exhibit properties of a multifractal process, with persistent long-term correlations (<span><math><msub><mi>α</mi><mn>0</mn></msub><mo>&gt;</mo><mn>0.5</mn><mo>)</mo><mspace></mspace></math></span>and the dominance of scaling of small fluctuations (<span><math><mi>r</mi><mo>&gt;</mo><mn>0</mn></math></span>). The spatial distribution of multifractal parameters exhibits a distinct gradient during the first period. The parameter <span><math><msub><mi>α</mi><mn>0</mn></msub></math></span> (persistence) increases from west to east and from south to north. In contrast, <span><math><mi>W</mi></math></span> (strength of multifractality) decreases from south to north in regions outside Eastern Europe, whereas it increases from south to north within Eastern Europe. In the second period, the area with stronger multifractality (higher <span><math><mi>W</mi></math></span> values) of temperature anomalies expanded significantly in Eastern Europe. The spatially averaged value and the range of the width <em>W</em> of the multifractal spectrum increased in the second period following the increase of the mean daily temperature. These results reveal the impact of climate change on multifractal properties of air temperature.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116386"},"PeriodicalIF":5.3,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data analysis of dynamical system for the optimization of disease dynamics through Neural Networks Paradigm","authors":"Aatif Ali ,&nbsp;Mei Sun ,&nbsp;Mohamed R. Ali","doi":"10.1016/j.chaos.2025.116284","DOIUrl":"10.1016/j.chaos.2025.116284","url":null,"abstract":"<div><div>Vaccine coverage and non-pharmaceutical interventions have great importance relative to public health in the current scenario of pandemic throughout the world. A compartmental model for assessing the vaccine and community contact rate (in light of social-distancing and isolation) coverage in symptomatic and asymptomatic public. In most biological phenomena, particularly infectious diseases, fractional models capture crossover behavior and provide deeper insight. Also, the disease informed neural network embedded with the proposed model to deduce the temporal evolution dynamics of the COVID-19 model. The Reproduction number determines the severity of disease computed by the next-generation approach. The mathematical model assesses the dynamics of Corona-virus based on biological parameters, which are estimated from recorded data by the least square curve technique. The proposed model shows precise predictions of the real cases. The COVID-19 data of Pakistan, suggest that the vaccine efficacy is found to be useful with adoption of moderately (50% reduction of baseline value) could prevent 70%–80% of the projected infected persons over 100 days. While the contact rates impact on epidemiological outcomes is highly nonlinear, which indicates the high value to eradicate the pandemic if the underlying contact rate is relatively low. Our study urge that the contact rates (social distancing and isolation etc.) and vaccine coverage with high efficacy has probably high value in curtailing the burden of the pandemic. Additionally, we discuss how neural networks may predict disease spread and do so with the robustness and effectiveness of neural networks. The deep learning method predicts the dynamics with forecast their progression and demonstrates the high potential in combination with compartmental model. Furthermore, the results demonstrate that neural networks outperform traditional approaches in forecasting complex disease dynamics, determining crucial thresholds, and refining suppression strategies, offering important public health insights. Additionally, this strategy opens the door for more extensive artificial intelligence integration in healthcare optimization.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116284"},"PeriodicalIF":5.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738966","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Delta-shock solution for the nonhomogeneous Euler equations of compressible fluid flow with Born–Infeld equation of state","authors":"Shiwei Li,&nbsp;Jiahui Yang","doi":"10.1016/j.chaos.2025.116336","DOIUrl":"10.1016/j.chaos.2025.116336","url":null,"abstract":"<div><div>The Born–Infeld type fluid, which obeys the pressure–density relation where the pressure is positive, is introduced into the nonhomogeneous Euler equations of compressible fluid flow. It is discovered for the first time that, for the positive pressure, the delta-shock with Dirac delta function in density develops in the solutions, even though the considered system is strictly hyperbolic with two genuinely nonlinear characteristic fields. First, the Riemann problem for the considered system is solvable with five kinds of structures by variable substitution method. For the delta-shock, the generalized Rankine–Hugoniot relation and entropy condition are clarified. Then it is discovered that as <span><math><mrow><mi>A</mi><mo>→</mo><mn>0</mn></mrow></math></span>, the solution consisting of two shocks converges to the delta-shock solution of zero-pressure Euler equations with friction; the delta-shock solution converges to that of zero-pressure Euler equations with friction; the solution containing two rarefaction waves converges to the vacuum solution of zero-pressure Euler equations with friction. Finally, the theoretical analysis is validated by the numerical results.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116336"},"PeriodicalIF":5.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of myocardial ischemia components in overdrive pacing of spiral waves","authors":"Sergei F. Pravdin ,&nbsp;Alexander V. Panfilov","doi":"10.1016/j.chaos.2025.116332","DOIUrl":"10.1016/j.chaos.2025.116332","url":null,"abstract":"<div><div>Dangerous cardiac arrhythmias occur often due to ischemic heart disease. One of the most important methods for removing an arrhythmia is low-voltage electrotherapy, in particular overdrive pacing, that is stimulation from an implanted cardioverter with a period slightly less than the arrhythmia period. The main aim of this paper is to study how ischemia can affect overdrive pacing of arrhythmias caused by rotating spiral waves. We performed simulations using the ten Tusscher–Panfilov 2006 model for human cardiac tissue and studied how specific components of ischemia, such as hyperkalemia, hypoxia and acidosis, affect the dynamics of spiral waves and overdrive pacing. The hyperkalemia increased the spiral wave period more than twofold and caused meandering. Hypoxia slightly decreased the period. Acidosis caused meandering and spontaneous drift, which can result in the disappearance of spiral waves. Overall, the ischemia increased the efficiency of overdrive pacing, an effect that was mainly due to hyperkalemia.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116332"},"PeriodicalIF":5.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extinction and persistence of a stochastic HBV model","authors":"Xiangkui Zhao,&nbsp;Ting Li","doi":"10.1016/j.chaos.2025.116339","DOIUrl":"10.1016/j.chaos.2025.116339","url":null,"abstract":"<div><div>We propose a stochastic model of the Hepatitis B Virus (HBV) and investigate viral extinction, persistence, and average residence time. To predict whether HBV will persist in the long term, we construct a crucial stochastic threshold. The establishment of this threshold faces some challenges due to the coexistence of predation and competition mechanisms in the model. To overcome this challenge, we integrate the interactions between infected hepatocytes and free virions into a unified equation, defining the crucial stochastic threshold. Our study shows that increased noise stabilizes the model when it approaches the infection-free equilibrium, but causes instability when the model approaches the infected equilibrium. This finding provides important theoretical basis for predicting HBV transmission and formulating intervention strategies. In addition, we provide detailed numerical simulations to support our conclusions.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116339"},"PeriodicalIF":5.3,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simple tunable generator of neuron-like activity","authors":"Lev V. Takaishvili ,&nbsp;Vladimir I. Ponomarenko ,&nbsp;Ilya V. Sysoev","doi":"10.1016/j.chaos.2025.116316","DOIUrl":"10.1016/j.chaos.2025.116316","url":null,"abstract":"<div><div>This study aims to develop a new electronic realization of a neuron. We based our work on a previously constructed circuit and modified it to reduce the number of elements. All modeling was done using ngSPICE circuit simulator. For the new developed circuit current–voltage characteristics were constructed, then dependence of signal amplitude on resistance of potentiometer was measured. In this way, we found that oscillations arose as a result of Andronov–Hopf bifurcation like in the FitzHugh–Nagumo neuron. Various implementations of nonlinearity were considered and the dependence of the shape of the generated signal on the asymmetry of the nonlinear element was investigated. It is shown that with increasing asymmetry this signal becomes more similar to nonlinear spikes, and with decreasing asymmetry it approaches the signal of a strongly nonlinear van der Pol oscillator. The oscillation frequency is mainly determined by the resonant frequency of the circuit and weakly depends on asymmetry: the period slightly decreases with increasing asymmetry. As a result, we developed a new simplified electronic neuron of FitzHugh–Nagumo type simple for hardware realization and modification.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116316"},"PeriodicalIF":5.3,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"M-shape, lump, homoclinic breather and other soliton interaction of the Landau-Ginzburg-Higgs model in nonlinear fiber optics","authors":"Abdullah ,&nbsp;Ghaus ur Rahman ,&nbsp;J.F. Gómez-Aguilar","doi":"10.1016/j.chaos.2025.116335","DOIUrl":"10.1016/j.chaos.2025.116335","url":null,"abstract":"<div><div>This study investigates the intricate dynamics of different types of solitons and their interactions within the framework of the Landau-Ginzburg-Higgs model as applied to nonlinear fiber optics. Employing the Hirota bilinear transformation technique, we derive a range of analytical soliton solutions, and demonstrating their rich and diverse behaviors. The proposed methodology provides a more comprehensive framework for analyzing transport processes by expanding these equations. M-shaped rational wave solutions with one kink, M-shaped rational waves with two kinks having bright and dark effects, periodic cross-kink with bright and dark waves, lump mixed-type waves, homoclinic breathers, and breather waves are among the various types of solitons. These many waveforms make it clear, soliton movement within optical fiber is extremely essential. They also offer valuable information that could influence soliton-based signal processing, optical communication systems, drug research, and other scientific fields. This extension of methodology aids in understanding the intricacy of soliton transport and identifying the intricate mechanisms. Additionally, by selecting various constant values, we create 3D and related contour plots to be aware of the physical interpretations of these solutions. Therefore, we get superior physical behaviors from these solutions.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116335"},"PeriodicalIF":5.3,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-rate discretely-modulated continuous-variable quantum key distribution using quantum machine learning","authors":"Qin Liao ,&nbsp;Zhuoying Fei ,&nbsp;Jieyu Liu ,&nbsp;Anqi Huang ,&nbsp;Lei Huang ,&nbsp;Yijun Wang","doi":"10.1016/j.chaos.2025.116331","DOIUrl":"10.1016/j.chaos.2025.116331","url":null,"abstract":"<div><div>Continuous-variable quantum key distribution (CVQKD) is one of the promising ways to ensure information security. In this paper, we propose a high-rate scheme for discretely-modulated (DM) CVQKD using quantum machine learning technologies, which divides the whole CVQKD system into three parts, i.e., the initialization part that is used for training and estimating quantum classifier, the prediction part that is used for generating highly correlated raw keys, and the data postprocessing part that generates the final secret key string shared by Alice and Bob. To this end, a low-complexity quantum <span><math><mi>k</mi></math></span>-nearest neighbor (Q<span><math><mi>k</mi></math></span>NN) classifier is designed for predicting the lossy discretely-modulated coherent states (DMCSs) at Bob’s side. The performance of the proposed Q<span><math><mi>k</mi></math></span>NN-based CVQKD especially in terms of machine learning metrics and complexity is analyzed, and its theoretical security is proved by using semi-definite program (SDP) method. Numerical simulation shows that the secret key rate of our proposed scheme is explicitly superior to that of the existing DM CVQKD protocols, and it can be further enhanced with the increase of modulation variance.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116331"},"PeriodicalIF":5.3,"publicationDate":"2025-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143738353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How colored noise impacts excitation and suppression of calcium oscillations: Stochastic sensitivity analysis","authors":"Lev Ryashko","doi":"10.1016/j.chaos.2025.116338","DOIUrl":"10.1016/j.chaos.2025.116338","url":null,"abstract":"<div><div>In this paper, we study the specificity of the colored noise in the stochastic calcium dynamics. As a deterministic framework, the Li-Rinzel model with the frequency modulation of calcium oscillations is used. For the cases of mono- and bistability, a parametric description of the dependence of the dispersion of random states on correlation time and colored noise intensity is given. In studying the phenomenon of stochastic excitation of spike oscillations, we localize the range of the correlation parameter of the colored noise inducing coherence resonance. A probabilistic analysis of the suppression of calcium oscillations by noise is carried out. The constructive capabilities of the stochastic sensitivity technique in colored-noise-induced generation and suppression of calcium oscillations are demonstrated.</div></div>","PeriodicalId":9764,"journal":{"name":"Chaos Solitons & Fractals","volume":"196 ","pages":"Article 116338"},"PeriodicalIF":5.3,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}