Publikační činnost IT4Innovations / Publications of IT4Innovations (9600)

Permanent URI for this collectionhttp://hdl.handle.net/10084/96109

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Photoexcited species localize on solvent-accessible fluorophore-rich domains inside carbon dots
(Elsevier, 2026) Langer, Michal; Zdražil, Lukáš; Rogach, Andrey L.; Osella, Silvio; Otyepka, Michal
Understanding the optical properties of luminescent carbon dots (CDs) at the electronic level is essential for engineering their light-responsive behavior. The localization of photoexcited species and the pathways of their de-excitation govern CD performance in sensing, bioimaging, and emerging photocatalytic applications. Yet, the underlying mechanisms remain unresolved. Here, we combine multiscale simulations with experiments on CDs synthesized from citric acid (CA) and ethylenediamine (EDA), precursors capable of forming the molecular fluorophore 5-oxo-1,2,3,5-tetrahydroimidazo[1,2-alpha]pyridine-7-carboxylic acid (IPCA). All-atom molecular dynamics simulations in water reveal that CA-EDA oligomeric condensation products containing IPCA units spontaneously assemble into dynamic similar to 2 nm nanoparticles with amorphous internal structures and stacked domains reminiscent of those observed in transmission electron microscopy images of CDs. Time-dependent density functional theory (TD-DFT) calculations show that photoexcited carriers are generated in these domains and remain spatially distributed, not confined to the CD core. Quenching experiments with Hg2+ confirm their accessibility to the environment. We therefore propose a structural model of fluorophore-rich domains embedded in an amorphous carbonaceous matrix, explaining the quasi-spherical morphology and characteristic blue photoluminescence. This model provides a mechanistic basis for fluorescence sensing and photocatalysis and establishes a framework for rational design of CDs with tailored photophysical and catalytic properties.
An effective numerical method for studying the fractal-fractional smoking model
(World Scientific Publishing Co Pte Ltd, 2025) Adel, M.; Khader, M. M.; Alraddadi, I.; Sweilam, N. H.; Riaz, M. B.; Ahmad, Hijaz
Worldwide, smoking is a common social practice, especially in places like schools and on important occasions. The World Health Organization (WHO) states that smoking is the third leading cause of death worldwide and the most significant avoidable cause of disease. Thus in this study, we present the solution behavior of the fractal-fractional (FF) smoking model. Using an effective numerical integration technique, the discretized system of FF differential equations that results is numerically integrated. By using RK4 to evaluate the numerical solution, we can meet the requirements for both efficiency and accuracy in the given approach. In the hope of providing some recommendations through which to reduce the risks of this bad behavior, the effect of some parameters and external factors affecting the solution behavior of this proposed mathematical model was studied, including the recruitment rate (due to immigration or birth) and the smoking cessation rate. The results show that the implemented technique is a straightforward and efficient tool for modeling the solution for these models.
Enhancing thermoelectric properties of ScN films through twin domains
(Elsevier, 2025) More-Chevalier, J.; Wdowik, U.D.; Martan, J.; Baba, T.; Cichoň, S.; Levinský, P.; Legut, D.; de Prado, E.; Hruška, P.; Pokorný, J.; Bulíř, J.; Beltrami, C.; Mori, T.; Novotný, M.; Gregora, I.; Fekete, L.; Volfová, L.; Lančok, J.
Tailoring thermoelectric properties of ScN-based materials is of vital importance for their application, particularly at high operating temperatures. Here, we report on the thermoelectric properties of the ScN layers deposited on MgO (001) substrates by the DC reactive magnetron sputtering. The microstructure of the produced thin films is examined by X-ray diffraction and atomic force microscopy, while their chemical composition and contamination by defects are determined by X-ray photoelectron spectroscopy. The effect of temperature on the phonon properties of ScN layers, having implications for their thermoelectric properties, is explored by Raman spectroscopy. The results of our experiments are confronted with those following from the first-principles studies. We find that the ScN/MgO(001) layers with twin-domain structure reveal enhanced thermoelectric properties at elevated temperature as compared to those measured for almost defect- and domain-free layers, namely, enlarged Seebeck coefficient by about 30% and over two and a half times increased figure of merit at 800 K. Therefore, structural twin domains in thin ScN film appear to be a simple and rather stable solution for the improvement of its thermoelectric properties at elevated temperatures.
Distributional properties of the entropy transformed Weibull distribution and applications to various scientific fields
(Springer Nature, 2024) Sindhu, Tabassum Naz; Shafiq, Anum; Lone, Showkat Ahmad; Al-Mdallal, Qasem M.; Abushal, Tahani A.
A novel two-parameter continuous model titled the entropy-transformed Weibull (ET-W) distribution has been developed via the entropy transformation. A new framework has been investigated and found to meet the criteria of the probability function. By significantly improving the functional shape and having the ability to model the most likely form of the hazard rate function, this novel modification has increased the adaptability of typical model. Some of its core characteristics, such as its statistical and computational features, are simply and clearly presented. To examine the ultimate performance of maximum likelihood estimators during the process of estimating model parameters, a comprehensive simulation analysis has been conducted. The effectiveness of the suggested distribution is illustrated through the modeling of real datasets.
Phase transition driven Zn-Ion battery with laser-processed V2C/V2O5 electrodes for wearable temperature monitoring
(Wiley, 2025) Deshmukh, Sujit; Vaghasiya, Jayraj V.; Michalička, Jan; Langer, Rostislav; Otyepka, Michal; Pumera, Martin
Flexible power supply devices present significant potential for wearable bioelectronics within the Internet of Things. Aqueous zinc-ion batteries have emerged as a viable and safe alternative for power supply in flexible electronics. Nevertheless, typical battery behaviors are generally detrimental with unfavorable phase transition of electrodes, which invariably lead to rapid performance degradation. Here, extraordinary capacity enhancement of 150% is presented, sustained over 60 000 cycles, attained using vanadium carbide MXene (V2C)/vanadium pentoxide (V2O5) heterostructure as cathode. The unique cathode material is created through the rational engineering of MAX (V2AlC), employing a single-step laser writing process. The ultrastable Zn ion battery stands in stark contrast to all previously reported counterparts, which typically exhibit capacity degradation within a few hundred/thousand cycles. The primary mechanisms driving this enhancement include the delamination of V2C MXene and an unexpected favorable phase transition during cycling. Additionally, a wearable power supply is constructed using a series configuration and is integrated with a commercial temperature sensor for wireless, real-time body temperature monitoring. This study highlights the critical role of electrode design for advanced wearable bioelectronics.
Study of complex dynamics and novel soliton solutions of the Kraenkel-Manna-Merle model describing saturated ferromagnetic materials
(Elsevier, 2024) Jhangeer, Adil; Alhussain, Ziyad A.; Raza, Nauman; Farman, Muhammad
This paper introduces a framework for nonlinear short wave propagation in an external field for saturated ferromagnetic materials with zero conductivity: the Kraenkel-Manna-Merle system. New solutions are produced via the G ' /(bG ' + G + a )-expansion technique. The suggested method is easier to understand, more precise, and simpler to compute. Specifically, a set of singular-periodic and kink-shaped exact soliton solutions is produced. Contour plots, 3D, and 2D visualizations with suitable parametric values are employed to present the computed solutions, which are derived through constraint conditions. For the development of certain novel soliton structures, the arbitrary functions in the solutions are selected. Moreover, bifurcation and chaos theory are applied to the primary dynamical system in order to provide a qualitative analysis of the system under study. Phase portraits of bifurcation are presented at fixed locations to illustrate different situations about parameter values in the dynamic system. However, adopting techniques for identifying chaos in a dynamical system and applying an external force verifies the occurrence of chaotic behavior in system. These results offer new perspectives that can enhance understanding of the dynamics of the KMM system.
Second-order anisotropy due to magnetostriction for L10-FePt
(Elsevier, 2025) Legut, Dominik; Nieves, Pablo
The effective magnetocrystalline anisotropy energy associated with magnetostriction is studied for tetragonal L10-FePt by means of first-principles calculations, which is expressed in terms of the intrinsic anisotropy for an undeformed crystal, the magnetostrictive coefficients, and the elastic tensor. A very small correction is found for the first anisotropy constant Delta K1/K1 = 0 . 07 %, while a much more significant contribution is obtained for the second one Delta K2/K2 = 21.86%. General analysis of this effect for tetragonal crystals is provided, finding that Delta K1 will be always positive for any stable phase with this symmetry. The potential implications and applications of these results are discussed.
Improved performance of single sided axial flux for reduction in cogging torque (IMPACT)
(Elsevier, 2025) Dawood, Ahmed; Ikram, Junaid; Riaz, Muhammad Bilal; Alimgeer, Khurram Saleem; Javeed, Shumaila
Pulsating torque contains two components, namely torque ripples and cogging torque. The decrease in pulsating torque is sought by the electrical machine designers. In PM machine design cogging torque is a concern since it adds undesirable harmonics to pulsating torque. Hence, in this paper a single-sided axial flux permanent magnet (AFPM) machine is proposed having an arc shaped skew magnets to reduce the cogging torque of a suggested machine. For high efficiency, stator sided iron must be unsaturated and torque ripples are nearby zero. Research aims to design and optimize Single Sided Slotless AFPM machines. Mathematical calculations and sizing equations are used to design the machine, and the simulation tools Finite Eliminate Method (FEM) is used to simulate the machine. Latin Hypercube Sampling (LHS) is used to create samples, kriging method is applied to approximate the model and optimized model is obtained by using Genetic Algorithm (GA).
Unraveling the competition between charge and energy transfer in 0D/2D nanographene-graphene heterojunctions
(Springer Nature, 2024) Wlazło, Mateusz; Langer, Michal; Semchuk, Oleksandr Y.; Osella, Silvio
The charge and energy transfer processes in photoexcited 0D/2D donor/graphene heterojunctions occur through multiple different pathways. A donor deexcitation event occurring in the most prevalent F & ouml;rster energy transfer mechanism (strongly favored over Dexter transfer in van der Waals heterojunctions) prevents charge transfer from taking place, thus creating a competition between the two processes. By applying a robust computational approach, we describe the two processes from first principles and quantify their rates using F & ouml;rster and Marcus theories. We consider nanojunctions where the donor are nanographenes with varying size and symmetry, and discern important trends, e.g., the symmetry-induced quenching, or the enhancement due to increased size. We observe that heterojunctions where nanographenes do not have a center of symmetry show decreased photoinduced hole and energy transfer rates, which can then be recovered by increasing the delocalization length, whereas for centrosymmetric nanographenes both hole and energy transfer processes are enhanced. Nevertheless, the hole transfer rate dominates over the energy transfer process, providing a new computation-driven design principle for obtaining a high-charge transfer junction with minimized contribution of the competing energy transfer.
Soliton dynamics and qualitative analysis of the (2+1)-dimensional Konopelchenko-Dubrovsky system
(Elsevier, 2026) Hussain, Amjad; Qureshi, Meerub; Jhangeer, Adil; Zeeshan, Muhammad
The Konopelchenko-Dubrovsky (KD) model, which predicts the propagation of nonlinear waves in various physical media, including fluids in elastic tubes, dusty plasmas, and highly nonlinear optical systems, is investigated in this study using a powerful analytical method known as the Jacobi elliptic function (JEF) method. Numerous accurate wave solutions, including various stable wave forms and pulse shapes and different kinds of trigonometric and hyperbolic wave forms, are produced by this method. We present graphical representations of the dynamical behavior of the governing equation using various tools like phase portraits, time series and sensitivity analysis, Poincare maps, power spectra, and analysis of the system's energy and stability. The qualitative analysis of the system in terms of its Hamiltonian structure makes it possible to distinguish bistable double-well and stable single-well potential energy landscapes, which are shown to correspond directly to the formation of kink solitons and periodic wave solutions, respectively. This paper provides a more physical background to the bifurcations of solutions and the changeovers between various wave forms. In addition to strengthening our knowledge of nonlinear wave propagation, the study offers a flexible framework for investigating additional nonlinear evolution equations in applied scientific and engineering settings.
Unraveling the complexity of solitary waves in the Klein-Fock-Gordon equation: dynamical insights into bifurcation and chaos analysis
(Springer Nature, 2024) Tariq, Muhammad Moneeb; Riaz, Muhammad Bilal; Rehman, Muhammad Aziz Ur; Dilawaiz
Soliton resonances and soliton interaction have gained significant attention in recent years within the field of nonlinear science and engineering due to their promising potential for various applications. This research provides a comprehensive analysis of the soliton interaction dynamics described by the nth-order Klein-Fock-Gordon equation. In this study, we used the improved modified Sardar subequation and modified Khater method to find the soliton solution to the nonlinear third-order Klein-Fock-Gordon equation. We construct dark, bright, kink, and periodic optical solitons using the modified Sardar subequation and Khater methods. We employ the suitable traveling wave transformation to convert the model equation into an ordinary differential equation. To analyze the physical behavior of the model, we graphically plotted some solutions, selecting appropriate parameter values in two-dimensional, three-dimensional, and contour plots. We examine the phase portrait of the equilibrium point to convert the equation into a planar dynamical system using the Galilean transformation. We conduct a sensitivity analysis to determine how sensitive our system is to the initial condition. When we apply an additional external force to the system, we also examine the chaotic analysis, observing how the dynamical system responds to various forces and comparing the patterns of periodic, quasi-periodic, and chaotic behavior. In this study, we performed the calculations using the Mathematica and Maple software programs.
Symmetry analysis, dynamical behavior, and conservation laws of the dual-mode nonlinear fluid model
(Elsevier, 2025) Jhangeer, Adil; Beenish; Říha, Lubomír
The study aims to analyze conservation laws and dynamics of the dual-mode Gardner equation for ideal fluid models. Lie symmetry analysis is applied to find symmetry generators, which in turn describe translation symmetries and abelian algebra. Lie theory converts the equation into a nonlinear ordinary differential equation using similarity variables. The model is transformed into a planar dynamical system via Galilean transformation, with phase portraits generated using bifurcation parameters. Runge-Kutta method is utilized to compute both super nonlinear and nonlinear wave solutions, with all solutions illustrated in the phase plane. Sensitivity and multistability analysis are conducted to examine chaotic behavior, quasiperiodic dynamics, and time series. Lyapunov characteristic exponents are discussed for chaos assessment. Numerical simulations reveal significant dynamical changes with alterations in frequencies and amplitude values. Explicit solutions are constructed via the power series method. Exploration of phase velocity and dispersion effects on the equation is done through modulation instability criteria. The multiplier scheme characterizes conserved vectors.
Characterization of p-adic mixed λ-central bounded mean oscillation space via commutators of p-adic hardy-type operators
(Wiley, 2024) Sarfraz, Naqash; Riaz, Muhammad Bilal; Mehmood, Sajid; Zaman, Mir
In this note, we define p-adic mixed Lebesgue space and mixed lambda-central Morrey-type spaces and characterize p-adic mixed lambda-central bounded mean oscillation space via the boundedness of commutators of p-adic Hardy-type operators on p-adic mixed Lebesgue space. Moreover, we also furnish boundedness of commutators of p-adic Hardy-type operators generated with p-adic mixed lambda-central bounded mean oscillation on mixed lambda-central Morrey space.
Computation of dynamic deflection in thin elastic beam via symmetries
(Elsevier, 2024) Majeed, Zain; Jhangeer, Adil; Mahomed, F. M.; Zaman, F. D.
The deflection profiles governed by Euler Bernoulli's fourth-order equations under varied applied loads are investigated in this research. This study provides essential insights for engineers designing aircraft components, bridges, and similar structures, ensuring system safety and efficiency. The investigation emphasizes critical factors such as amplitude and frequency, load history, and material properties. Initially, conservation laws of the equations with applied loads are derived by expressing them in the Euler-Lagrange form, where the resultant conservation laws satisfy the divergence expression. The association between symmetries and conservation laws is demonstrated, followed by the application of double reduction theory, which reduces both the variables and the order of the equation. Graphical representations of the outcomes illustrate the impact of load variations on the beam's deflection profiles. These visual aids facilitate a deeper understanding of the influence of different loading conditions. A comparison between varying loads is presented, showcasing the impact of these variations on structural behavior. The findings are crucial for enhancing structural design and ensuring safety under varied loading conditions, showcasing the novelties in the analytical approach and the practical applications of the derived results.
Computation of dynamic deflection in thin elastic beam via symmetries
(Elsevier, 2024) Majeed, Zain; Jhangeer, Adil; Mahomed, F. M.; Zaman, F. D.
The deflection profiles governed by Euler Bernoulli's fourth-order equations under varied applied loads are investigated in this research. This study provides essential insights for engineers designing aircraft components, bridges, and similar structures, ensuring system safety and efficiency. The investigation emphasizes critical factors such as amplitude and frequency, load history, and material properties. Initially, conservation laws of the equations with applied loads are derived by expressing them in the Euler-Lagrange form, where the resultant conservation laws satisfy the divergence expression. The association between symmetries and conservation laws is demonstrated, followed by the application of double reduction theory, which reduces both the variables and the order of the equation. Graphical representations of the outcomes illustrate the impact of load variations on the beam's deflection profiles. These visual aids facilitate a deeper understanding of the influence of different loading conditions. A comparison between varying loads is presented, showcasing the impact of these variations on structural behavior. The findings are crucial for enhancing structural design and ensuring safety under varied loading conditions, showcasing the novelties in the analytical approach and the practical applications of the derived results.
Stochastic dynamics and control in nonlinear waves with Darboux transformations, quasi-periodic behavior, and noise-induced transitions
(MDPI, 2026) Jhangeer, Adil; Imran, Mudassar
Stochastically forced nonlinear wave systems are commonly associated with complex dynamical behavior, although little is known about the general interaction of nonlinear dispersion, irrational forcing frequencies, and multiplicative noise. To fill this gap, we consider a generalized stochastic SIdV equation and examine the effects of deterministic and stochastic influences on the long-term behavior of the equation. The PDE was modeled using a stochastic traveling-wave transformation that simplifies it into a planar system, which was studied using Darboux-seeded constructions, Poincar & eacute; maps, bifurcation patterns, Lyapunov exponents, recurrence plots, and sensitivity diagnostics. We discovered that natural, implicit, and unique seeds produce highly diverse transformed wave fields exhibiting both irrational and golden-ratio forcing, controlling the transition from quasi-periodicity to chaos. Stochastic perturbation is demonstrated to suppress as well as to amplify chaotic states, based on noise levels, altering attractor geometry, predictability, and multistability. Meanwhile, OGY control is demonstrated to be able to stabilize chosen unstable periodic orbits of the double-well regime. A stochastic bifurcation analysis was performed with respect to noise strength sigma, revealing that the attractor structure of the system remains robust under stochastic excitation, with noise inducing only bounded fluctuations rather than qualitative dynamical transitions within the investigated parameter regime. These findings demonstrate that the emergence, deformation, and controllability of complex oscillatory patterns of stochastic nonlinear wave models are jointly controlled by nonlinear structure, external forcing, and noise.
Measuring the energy for the molecular graphs of antiviral agents: Hydroxychloroquine, Chloroquine and Remdesivir
(Elsevier, 2024) Aftab, Muhammad Haroon; Akgül, Ali; Riaz, Muhammad Bilal; Hussain, Muhammad; Jebreen, Kamel; Kanj, Hassan, Hassan
We consider the energy for the molecular graphs of antiviral agents like Hydroxychloroquine, Remdesivir and Chloroquine. These drugs play a vital role in the treatment of COVID-19. Let Gamma(1), Gamma(2) and Gamma(3) be the n-dimensional graphs of the molecular structures of antiviral agents Hydroxychloroquine, Chloroquine and Remdesivir, respectively. We define their energies as E '(Gamma(1)) = Sigma vertical bar lambda(i)'vertical bar, E '(Gamma 2) = Sigma vertical bar lambda(j)'vertical bar and E '(Gamma 3) = Sigma vertical bar lambda(k)'vertical bar, respectively. Where the sets {lambda(1)'(Gamma(1)), lambda(2)'(Gamma(1)), lambda(3)'(Gamma(1)), ..., lambda(n)'(Gamma(1))}, {lambda(1)'(Gamma(2)), lambda(2)'(Gamma(2)), lambda(3)'(Gamma(2)), ..., lambda(n)'(Gamma(2))} and { lambda(1)'(Gamma 3), lambda(2)'(Gamma 3), lambda(3)'(Gamma 3), ..., lambda(n)'(Gamma 3)} depict the eigenvalues for the adjacency matrices of Gamma 1, Gamma 2 and Gamma 3, respectively. We have developed some basic ideas and properties in order to measure the energies for the antiviral agents Hydroxychloroquine, Chloroquine and Remdesivir.
Phosphoric acid salts of amino acids as a source of oligopeptides on the early Earth
(Springer Nature, 2024) Šponer, Judit E.; Coulon, Rémi; Otyepka, Michal; Šponer, Jiří; Siegle, Alexander F.; Trapp, Oliver; Ślepokura, Katarzyna; Zdráhal, Zbyněk; Šedo, Ondrej
Because of their unique proton-conductivity, chains of phosphoric acid molecules are excellent proton-transfer catalysts. Here we demonstrate that this property could have been exploited for the prebiotic synthesis of the first oligopeptide sequences on our planet. Our results suggest that drying highly diluted solutions containing amino acids (like glycine, histidine and arginine) and phosphates in comparable concentrations at elevated temperatures (ca. 80 degrees C) in an acidic environment could lead to the accumulation of amino acid:phosphoric acid crystalline salts. Subsequent heating of these materials at 100 degrees C for 1-3 days results in the formation of oligoglycines consisting of up to 24 monomeric units, while arginine and histidine form shorter oligomers (up to trimers) only. Overall, our results suggest that combining the catalytic effect of phosphate chains with the crystalline order present in amino acid:phosphoric acid salts represents a viable solution that could be utilized to generate the first oligopeptide sequences in a mild acidic hydrothermal field scenario. Further, we propose that crystallization could help overcoming cyclic oligomer formation that is a generally known bottleneck of prebiotic polymerization processes preventing further chain growth.
Introducing the new arcsine-generator distribution family: An in-depth exploration with an illustrative example of the inverse weibull distribution for analyzing healthcare industry data
(Elsevier, 2024) Sindhu, Tabassum Naz; Shafiq, Anum; Riaz, Muhammad Bilal; Abushal, Tahani A.; Ahmad, Hijaz; Almetwally, Ehab M.; Askar, Sameh
The study is about a novel Arcsin-function based generator of new families of distributions. We chose the inverse Weibull distribution as the reference distribution to see if the generator could be employed. This generator helps for developing a distribution called the novel Arcsin inverse Weibull. The main features of the suggested distribution have been taken into account. Some of the indicators used in this class include the density function, complete and incomplete moments, average deviation, and aging indicators. The model's parameters are determined using the maximum likelihood method in both simulations and data analysis. The effectiveness of the suggested model in the healthcare sector is demonstrated by analyzing five sets of data, revealing its superior fit compared to the traditional inverse sine model, which is associated with the inverse Weibull model.
Rational design of MXene-based vacancy-confined single-atom catalyst for efficient oxygen evolution reaction
(Elsevier, 2024) Fu, Zhongheng; Hai, Guangtong; Ma, Xia-Xia; Legut, Dominik; Zheng, Yongchao; Chen, Xiang
Two-dimensional transition metal carbides (MXenes) have been demonstrated to be promising supports for single-atom catalysts (SACs) to enable efficient oxygen evolution reaction (OER). However, the rational design of MXene-based SACs depends on an experimental trial-and-error approach. A theoretical guidance principle is highly expected for the efficient evaluation of MXene-based SACs. Herein, highthroughput screening was performed through first-principles calculations and machine learning techniques. Ti3C2(OH)x, V3C2(OH)x, Zr3C2(OH)x, Nb3C2(OH)x, Hf3C2(OH)x, Ta3C2(OH)x, and W3C2(OH)x were screened out based on their excellent stability. Zn, Pd, Ag, Cd, Au, and Hg were proposed to be promising single atoms anchored in MXenes based on cohesive energy analysis. Hf3C2(OH)x with a Pd single atom delivers a theoretical overpotential of 81 mV. Both moderate electron-deficient state and high covalency of metal-carbon bonds were critical features for the high OER reactivity. This principle is expected to be a promising approach to the rational design of OER catalysts for metal-air batteries, fuel cells, and other OER-based energy storage devices. (c) 2024 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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