bluuebunny/crossref_metadata_2025 huggingface dataset:
Peridynamics modeling of coupled gas convection transport and thermal diffusion in heterogeneous porous media
Authors: Cheng Suifu , Guo Xu , Li Liping , Wang Penghui
Published: August 2024

Gas convection transport in porous media plays a pivotal role in various engineering and natural systems, such as oil and gas reservoir behavior and carbon dioxide sequestration. In response, this paper presents a novel peridynamics model for pressure-driven gas convection transport in porous media. By peridynamics, we mean a non-local continuum mechanics theory that accounts for interactions within a finite distance, allowing for the modeling of discontinuities and complex material behavior without relying on classical spatial derivatives. The proposed peridynamics model intends to provide a comprehensive account for simulating gas convection in porous media by incorporating key factors such as the Klinkenberg effect, thermal-flow coupling, and heterogeneous materials. The effectiveness, accuracy, and versatility of the proposed peridynamics approach are demonstrated by numerical results from benchmark examples and complex simulation scenarios. The validity and reliability of this peridynamics model are confirmed under various conditions through convergence studies, sensitivity analyses, and comparisons with finite element method results. Conclusions drawn from the validation studies are that the proposed framework is capable of addressing practical issues such as the prediction of pore pressure in high-temperature concrete and that the proposed methodology is accurate, stable, convergent, and a promising alternative to traditional methods.
Particles deposition on plates with different film cooling hole shapes for different blowing ratios and angles of attack
Authors: Liu Zhengang , Ruan Rongsheng , Zhang Yixuan , Lyu Yaguo , Liu Zhenxia
Published: August 2024

Turbine vanes may be subjected to the deposition of particles such as dust from the external environment. The deposition could affect their aerodynamic and cooling performances. As an effective cooling method, the film cooling could alter the deposition. In this paper, the deposition experiments at ambient temperature were conducted by using atomized wax as the substitute for real particles to investigate the influence of film cooling hole shapes on the deposition for different blow ratios and angles of attack. The results indicate that within the range of blowing ratios in this paper, the deposition on the pressure surface of different hole shapes increases with increasing blowing ratio. Among them, the cylindrical model exhibits the most significant variation in deposition, for example, with a relative increase of 94% in deposition when the blowing ratio was increased from 2.0 to 2.5. The CONSOLE test model showed a relative increase of 60%, while the conical and fan-shaped test model exhibited a relative increase of 20%. The conical, CONSOLE, and fan-shaped film cooling holes can mitigate the influence of the blowing ratio on the deposition of particles. Within the range of angle of attack in this paper, the deposition on the pressure surfaces with different hole shapes increases with the increase in the absolute value of angle of attack. The cylindrical test model exhibits the most significant variation. The conical and fan-shaped holes can mitigate the influence of the angle of attack on the deposition of particles.
Flow field analysis and aerodynamic drag optimization of non-pneumatic tires
Authors: Yuan Xiao-Hong , Zhai Ben-Qu , Su Chu-Qi , Liu Xun , Wang Yi-Ping
Published: August 2024

Numerical simulations were performed to analyze the external flow field characteristics of a non-pneumatic tire (NPT) with flexible spokes. The simulation results revealed that the acute shoulders and cavities formed by spokes are the principal contributors to the high aerodynamic drag and ventilation moment (VM). By changing the parameters of the shear bands, a significant reduction in the aerodynamic drag coefficient (Cd) and ventilation moment could be achieved. Taking the minimum aerodynamic drag coefficient and ventilation moment as optimization objectives, a five-factor and four-level orthogonal experiment was designed with the spoke thickness, spoke radial length, spoke curvature, spoke outer offset rate, and spoke inner offset rate as the design parameters. The optimal combination of spoke parameters was obtained by range analysis and variance analysis, with the reduction of Cd and VM by 6.25% and 16.55%, respectively. Meanwhile, the feasibility of optimization parameters of the shear bands and spokes was confirmed by mechanical performance test.
Nonexistence of closed timelike geodesics in Kerr spacetimes
Authors: Sanzeni Giulio
Published: August 2024

The Kerr-star spacetime is the extension over the horizons and in the negative radial region of the Kerr spacetime. Despite the presence of closed timelike curves below the inner horizon, we prove that the timelike geodesics cannot be closed in the Kerr-star spacetime. Since the existence of closed null geodesics was ruled out by the author in Sanzeni [arXiv:2308.09631v3 (2024)], this result shows the absence of closed causal geodesics in the Kerr-star spacetime.
Formation of metallic/oxide composites of Sn from SnO2 thin films with swift heavy ion irradiation
Authors: Gome Anil , Singh Fouran , Ganesan V. , Yadav Anand , Raghavendra Reddy V.
Published: August 2024

The present work reports the effects of 120 MeV Au9+ on structural and electronic properties of polycrystalline SnO2 films of about 170 nm thickness prepared by spin-coating. 119Sn Mössbauer measurements are used to probe the electronic properties. The observed isomer-shift values clearly indicate Sn4+ for the pristine sample and its progressive reduction to Sn2+ and eventually to the metallic Sn state at higher fluence values. These observations are corroborated by x-ray diffraction, Raman, and x-ray photo-electron spectroscopy measurements. The x-ray diffraction measurements indicate the complete amorphization of the tin oxide phase, while the recrystallization of the metallic Sn phase with irradiation. The optical bandgap is observed to vary with ion beam irradiation. The observations indicate the possibility of tuning the electronic configuration of Sn in tin oxide thin films with swift heavy ion beam irradiation, and the results are explained in terms of the thermal-spike model of swift heavy ion irradiation.
Conservation laws, nonlocal symmetries, and exact solutions for the Cargo–LeRoux model with perturbed pressure
Authors: Maurya Sandhya , Zeidan Dia , Pradhan Pabitra Kumar , Pandey Manoj
Published: August 2024

In this study, we have formulated conservation laws for the Cargo–LeRoux model by utilizing both the direct multiplier technique and nonlinear self-adjointness. These conservation laws include a perturbed state pressure equation. Using conservation laws, we have demonstrated a methodology for generating explicit solutions for nonlinear partial differential equations and verified its effectiveness using the local conservation laws specific to the Cargo–LeRoux model. Our investigation indicates that these conservation laws yield solutions distinct from those obtained through group invariance methods. Moreover, we have established a comprehensive framework for constructing a network of partial differential equations which are nonlocally related to the governing system. This network includes systems derived from local conservation laws and symmetry methods. Additionally, we have classified the nonlocal symmetries arising from these potential systems and applied them to discover exact solutions for the Cargo–LeRoux model.
Transient modes for the coupled modified Korteweg–de Vries equations with negative cubic nonlinearity: Stability and applications of breathers
Authors: Wong C. N. , Yin H. M. , Chow K. W.
Published: August 2024

Dynamics and properties of breathers for the modified Korteweg–de Vries equations with negative cubic nonlinearities are studied. While breathers and rogue waves are absent in a single component waveguide for the negative nonlinearity case, coupling can induce regimes of modulation instabilities. Such instabilities are correlated with the existence of rogue waves and breathers. Similar scenarios have been demonstrated previously for coupled systems of nonlinear Schrödinger and Hirota equations. Both real- and complex-valued modified Korteweg–de Vries equations will be treated, which are applicable to stratified fluids and optical waveguides, respectively. One special family of breathers for coupled, complex-valued equations is derived analytically. Robustness and stability of breathers are studied computationally. Knowledge of the growth rates of modulation instability of plane waves provides an instructive prelude on the robustness of breathers to deterministic perturbations. A theoretical formulation of the linear instability of breathers will involve differential equations with periodic coefficient, i.e., a Floquet analysis. Breathers associated with larger eigenvalues of the monodromy matrix tend to suffer greater instability and increased tendency of distortion. Predictions based on modulation instability and Floquet analysis show excellent agreements. The same trend is obtained for simulations conducted with random noise disturbances. Linear approaches like modulation instabilities and Floquet analysis, thus, generate a very illuminating picture of the nonlinear dynamics.
Modeling the photophoretic force on a perforated membrane
Authors: Sharipov Felix , Schafer Benjamin C. , Keith David W.
Published: August 2024

The photophoretic force exerted on an illuminated membrane vanishes when its size is much larger than the molecular mean-free-path. Perforations in the membrane can increase the force, but they make modeling the gas flow more difficult. In the present letter, a new model of gas interaction with a perforated surface is proposed. The direct simulation Monte Carlo method is used to calculate the flow-field and photophoretic force exerted on a perforated membrane, showing a significant increase in the force at high rarefaction parameters. This effect could be used to levitate membranes of a few centimeters in size at mesospheric altitudes.
Cooperation dynamics of prisoner's dilemma games on an evolutionary weighted network with heterogeneous preferences
Authors: Quan Ji , Zhang Yuanyuan , Chen Wenman , Wang Xianjia
Published: August 2024

Relationships between people in real life are dynamically changed with the interaction process, and due to the heterogeneous preferences, this change is different from person to person. Based on this observation, we propose a new spatial and weighted prisoner's dilemma game model with heterogeneous individuals. Two types of tags, namely, tag-F (concerned about social fairness) and tag-W (concerned about personal well-being), are introduced to describe individuals’ different preferences. The link weights indicating the interaction strength between individuals are updated based on different rules that depend on their tags. Through simulations, we verify that a large link weight control factor and a high proportion of tag-F individuals favor the emergence and persistence of cooperation. In addition, an increase in the link weight sensitivity factor favors the evolution of cooperation when the link weight control factor is small. Moreover, while the level of cooperation increases with the proportion of tag-F type in the population, contrary to our intuition, when the population consists entirely of tag-F individuals, in some cases, cooperation cannot reach a higher level compared with the situation when they are mixed with tag-W type. However, at high dilemma intensities, cooperators emerge only when the entire population consists of tag-F type. These results may provide some new insights into the impact of the evolutionary weighted network with heterogeneous preferences on collective cooperative behavior.
Initial imprint effect on dynamic mitigation of plasma instability
Authors: Kawata S.
Published: August 2024

We proposed a dynamic mitigation method for plasma instabilities based on a phase control to mitigate plasma instabilities and to smooth plasma non-uniformities [e.g., Phys. Plasmas, 19 (2012), 024503]. In plasmas, perturbation phase would be unknown in general, and instability growth rate is discussed. However, if the perturbation is introduced by, for example, an illumination non-uniformity of an input energy driver beam, the perturbation phase would be defined by the driver illumination non-uniformity itself. When the driver axis is controlled by its axis oscillation or wobbling motion, the perturbation phase would be known and controlled. By the superimposition of the growing phase-controlled perturbations, the overall plasma instability growth is mitigated. The dynamic mitigation method is effective to mitigate growths of various plasma instabilities. At the same time, it was found that the phase of the growing perturbations mitigated would be still defined by the initial imprint. In this paper, the initial imprint effect is focused on the dynamic mitigation mechanism in plasmas. The results in this paper demonstrate that the initial imprint effect is reduced by an appropriate pulse shaping of the oscillating or wobbling perturbation.
Numerical study on slamming characteristics of an elastic wedge based on a two-way coupled finite volume and modal superposition method
Authors: Han Bingbing , Li Hui , Guo Hao , Sun Zhiyong , Liu Ning
Published: August 2024

In marine engineering, fluid–structure interaction (FSI) problems caused by wave impact are prevalent and often accompanied by violent free-surface changes. To accurately capture the free-surface and optimize the solution strategy for FSI problems, this study proposes a solver (overInterISODyMFoam) that combines isoAdvector and overset for refined free-surface capturing and a partitioned approach that couples finite volume and modal superposition (FVMS) based on the preCICE platform for solving FSI wave impact problems. The performance of solver and the FVMS method are verified by comparing them to the experimental results of a 20° wedge entering the water. The results indicated that the free-surface capturing method proposed can achieve a sharper interface than the Multidimensional Universal Limiter with Explicit Solution method and exhibits less numerical dissipation at the spray front. As a three-dimensional two-way coupled method, the calculations of FVMS method are in good agreement with the experimental results. The average error for the pressure and stress peaks is approximately 5.60% and 4.52%, respectively. The FVMS method shows better applicability than the two-dimensional (2D) one-way coupled method. Due to the ignored elasticity effect, the slamming pressure peak and stress peak calculated by the 2D one-way coupled method are approximately 4%–11% and 6%–23% higher than the experimental results, respectively.
Immunomodulatory hydrogels for tissue repair and regeneration
Authors: Liu Xiangjun , Hu Yue , Ju Yikun , Yang Pu , Shen Naisi , Yang Anqi , Wu Rui , Fang Bairong , Liu Liangle
Published: August 2024

Tissue repair and regeneration have long been a focus of research, with growing evidence highlighting the role played by immunomodulation. The repair of tissue cells can be significantly promoted through the localized immunomodulation of tissues. Hydrogels are increasingly used in this field due to their biocompatibility, versatility, and relative ease of fabrication. This Review highlights the critical role of inflammation and immune development in the complex process of tissue repair after injury, highlighting the dynamic interactions between immune cells that ultimately influence the outcome of tissue healing. We also summarize the precise functions of immune cells and their responses in various tissue injury scenarios, which are critical for harnessing the full potential of immunomodulatory strategies to promote tissue repair. We discuss recent advances in drug-carrying hydrogels, which offer promising avenues for tissue regeneration with precise control of the immune environment for constructive tissue repair. Further advances in our understanding of the mechanisms driving inflammation and immune cell behavior during tissue injury are expected to foster the development of increasingly effective hydrogel-based immunomodulatory strategies to promote tissue repair and regeneration.
Floquet-Engineering Topological Phase Transition in Graphene Nanoribbons by Light
Authors: Huang 黄 Anhua 安华 , Ke 柯 Shasha 莎莎 , Guan 关 Ji-Huan 济寰 , Li 李 Jun 俊 , Lou 娄 Wen-Kai 文凯
Published: August 2024

Quasi-one-dimensional (1D) graphene nanoribbons (GNRs) play a crucial role in advancement of next-generation devices. Recent studies have suggested their potential to exhibit unique symmetry-protected topological phases defined by a Z
2 invariant. By employing both the tight-binding model and the Floquet theory, our investigation demonstrates the effective control of the topological phase within quasi-1D armchair GNRs (AGNRs) using elliptically polarized light, unveiling rich topological phase diagrams. Specifically, we observe that varying the amplitude of the light can induce transitions in the band gap (E
g) of AGNRs, leading to multiple changes in the system’s Z
2 invariant. Furthermore, for heterojunctions composed of different AGNR segments, the junction state can be either created or eliminated by the application of elliptically polarized light.
Creation of tungsten and platinum nanoparticles from nanosecond plasmas in water
Authors: Krettek O , Pottkämper P , Cignoni P , Tschulik K , von Keudell A
Published: August 2024

Nanosecond plasmas ignited inside water at tungsten and platinum/iridium electrode tips are used to create very small nanoparticles with radii around 1 nm. Due to the very high power density of 1016 W m–2 at an electrode hot spot with a diameter of 10 µm, the surface is ablated during the short plasma pulse, and the metal vapour expands in the cavitation bubble after the plasma. This creates a very large cooling rate and the formation of nanoparticles by condensation from the created metal vapour. Finally, the nanoparticles disperse in the liquid. This sequence is quantified by measuring the net tip erosion by shadowgraphy and the created nanoparticles by transmission electron microscopy and x-ray photoelectron spectroscopy. The condensation process is modelled in conjunction with cavitation theory for the expanding cavitation bubble, which shows very good agreement with experimental data.
Reconfigurable THz leaky-wave antennas based on innovative metal–graphene metasurfaces
Authors: Negri Edoardo , Fuscaldo Walter , Burghignoli Paolo , Galli Alessandro
Published: August 2024

Graphene ohmic losses notably hinder the efficiency of graphene-based terahertz (THz) devices. Hybrid metal–graphene structures have recently been proposed to mitigate this issue in a few passive devices, namely waveguide and Vivaldi antennas, as well as frequency selective surfaces. In this work, such a technique is extensively investigated to optimize the radiation performance of a THz Fabry–Perot cavity leaky-wave antenna based on a hybrid metal–graphene metasurface consisting of a lattice of square metallic patches interleaved with a complementary graphene strip grating. Theoretical, numerical, and full-wave results demonstrate that, by properly selecting the unit-cell features, a satisfactory trade-off among range of reconfigurability, antenna directivity, and losses can be achieved. The proposed antenna can find application in future wireless THz communications.
Research on remaining useful life prediction methods for rolling bearings based on a novel gated unit
Authors: Ma Ke , Huang Weiguo , Ding Chuancang , Shi Juanjuan , Wang Jun , Shen Changqing , Jiang Xingxing
Published: August 2024

The remaining useful life (RUL) of bearings in rotating machinery is continuously affected by time. To address this concern, an improved model based on gated recurrent unit is proposed by taking full advantage of the characteristics of recurrent neural networks to efficiently process sequence data. This model is then applied to different prediction scenarios. First, to construct training and test sets, the required feature data are extracted from the vibration signals of rolling bearings. A health indicator (HI) is required to be constructed as a label for indirect prediction, whereas RUL is directly used as a label for direct prediction. The model is then allowed to learn through training sets to determine its optimal parameters. Finally, test sets are used to predict HI or RUL step by step. The effectiveness and superiority of the novel model in indirect and direct predictions is demonstrated by the comparison of evaluation indexes for prediction results with lower prediction deviations than conventional methods.
Wafer defect pattern recognition based on differentiable architecture search with dual attention module
Authors: Dai Menghang , Liu Zhiliang , He Zixiao
Published: August 2024

Wafer defect pattern recognition is a crucial process for ensuring chip production quality. Due to the complexity of wafer production processes, wafers often contain multiple defect patterns simultaneously, making it challenging for existing deep learning algorithms designed for single defect patterns to achieve optimal performance. To address this issue, this paper proposes a dual attention integrated differentiable architecture search (DA-DARTS), which can automatically search for suitable neural network architectures, significantly simplifying the architecture design process. Furthermore, the integration of DA greatly enhances the efficiency of the architecture search. We validated our proposed method on the MixedWM38 dataset, and experimental results indicate that the DA-DARTS method achieves higher pattern recognition accuracy under mixed defect patterns compared to baseline methods, maintaining performance stability even on imbalanced datasets.
Impurity gas detection for SNF canisters using probabilistic deep learning and acoustic sensing*
Authors: Zhuang Bozhou , Gencturk Bora , Oberai Assad A , Ramaswamy Harisankar , Meyer Ryan , Sinkov Anton , Good Morris
Published: August 2024

Monitoring impurity gases in spent nuclear fuel (SNF) canisters is a novel structural health monitoring approach for SNF in dry storage. The SNF canisters are sealed containers that do not facilitate visual access to the inside. Acoustic sensing can be deployed by taking advantage of the pathways unobstructed by internal hardware. Although the ultrasonic time-of-flight measurement can provide valuable information, it is limited in its ability to discern the concentration of only one impurity gas. As such, deep learning algorithms, particularly convolutional neural networks (CNNs), offer a promising solution. In this study, CNN-based probabilistic deep learning models were implemented to detect and quantify multiple impurity gases in helium. An experimental platform was established to simulate canister conditions, and ultrasonic test data were collected. The presence of argon and air in helium at concentrations ranging from 0% to 1.2% at increments of 0.05% was considered. The multi-layer perceptron, decision tree, and logistic regression classifiers achieved high accuracies when distinguishing pure helium from helium with impurities. CNN with dropout layers and CNN using maximum likelihood estimation showed a similar performance, indicating their ability to capture uncertainties. The ensemble CNN model exhibited improved predictions and the ability to balance individual gas concentration by integrating 1D- and 2D-CNN models. These findings contribute probabilistic deep learning solutions for impurity gas detection and analysis within SNF canisters, thus ensuring safe storage and management of SNFs.
2D TMDC aging: a case study of monolayer WS2 and mitigation strategies
Authors: Wyndaele P-J , de Marneffe J-F , Slaets R , Groven B , Franquet A , Brüner P , Grehl T , Gendt S De
Published: August 2024

Due to their unique properties, two-dimensional transition metal dichalcogenides (2D TMDCs) are considered for diverse applications in microelectronics, sensing, catalysis, to name a few. A common challenge in 2D TMDC research is the film’s inherent instability i.e. spontaneous oxidation upon ambient exposure. The present study systematically explores the effect aging on the film composition and photoluminescent properties of monolayer WS2, synthetically grown by metal-organic chemical vapor deposition. The aging rate is investigated for different oxygen- (i.e. O2 gas concentration and humidity) and light-controlled environments. Simple mitigation strategies that do not involve capping the 2D TMDC layer are discussed, and their effectiveness demonstrated by benchmarking the evolution in photoluminescence response against ambient exposed monolayer WS2. These results highlight the need to store 2D TMDCs in controlled environments to preserve the film quality and how future studies can account for the aging effect.
Progression of total training volume in resistance training studies and its application to skeletal muscle growth
Authors: Hammert William B , Kataoka Ryo , Yamada Yujiro , Song Jun Seob , Kang Anna , Spitz Robert W , Loenneke Jeremy P
Published: August 2024

Progressive overload describes the gradual increase of stress placed on the body during exercise training, and is often quantified (i.e. in resistance training studies) through increases in total training volume (i.e. sets × repetitions × load) from the first to final week of the exercise training intervention. Within the literature, it has become increasingly common for authors to discuss skeletal muscle growth adaptations in the context of increases in total training volume (i.e. the magnitude progression in total training volume). The present manuscript discusses a physiological rationale for progressive overload and then explains why, in our opinion, quantifying the progression of total training volume within research investigations tells very little about muscle growth adaptations to resistance training. Our opinion is based on the following research findings: (1) a noncausal connection between increases in total training volume (i.e. progressively overloading the resistance exercise stimulus) and increases in skeletal muscle size; (2) similar changes in total training volume may not always produce similar increases in muscle size; and (3) the ability to exercise more and consequently amass larger increases in total training volume may not inherently produce more skeletal muscle growth. The methodology of quantifying changes in total training volume may therefore provide a means through which researchers can mathematically determine the total amount of external ‘work’ performed within a resistance training study. It may not, however, always explain muscle growth adaptations.
Drift instabilities driven by slab ion temperature gradient in suprathermal plasmas
Authors: Guo Ran
Published: August 2024

The drift instabilities driven by the slab ion temperature gradient (ITG) in Kappa-distributed plasmas are investigated by the kinetic method. The linear dispersion relation is given in an integral representation involving only the standard plasma dispersion function. The wave frequency and growth rate are derived without the density inhomogeneity. Numerical solutions of the dispersion equation are conducted to show the different effects of the suprathermal ions and electrons. We find that the suprathermal ions can enhance the instability in large wavenumbers but suppress it in small wavenumbers. Thus, the suprathermalization of ions could be one of the factors leading to a lower limit of wavenumbers for the ITG instabilities. Besides, the numerical calculations also imply that the thermal speed ratio affects the intensities of the suprathermal effects. Finally, in the presence of density inhomogeneity, the ITG instability boundary is numerically analyzed.
Temperature-dependent electrical investigations and explication of the equivalent operational Warburg impedance by Bode and Nyquist plots of Yb3+ doped silicate glass
Authors: J Gracie P , D Geetha
Published: August 2024

Multi-component silicate glass doped with Yb3+ and synthesized by the sol–gel technique was subjected to broadband dielectric spectroscopy to determine the energy storage and electrode functionalities. Raman spectroscopy confirms the existence of the silicate and phosphate tetrahedra, with the structural alterations by the non-bridging oxygens to form a compact glass network. Bode and Nyquist impedance plots suggest the suitability of the glass as electrodes, whose functionality is simulated to a circuitry constituting two parallel combinations of a resistor and constant phase element each, and in series with Warburg diffusion impedance element (W). The glass evinces a high conductivity and corrosion resistance, suggestive of electrodes in batteries for energy storage. The inception of W on the low-frequency domain indicates significant space charge polarization, and augmented dielectric constants. The capacitance of 0.9 nF at 100 Hz demonstrates its potentiality for multi-layer dielectric substrates in radio frequency capacitors to enhance electrical energy storage.
Chemical and green synthesized Co/Ni-doped hematite nanoparticles for enhancing the photocatalytic and antioxidant properties
Authors: Kumar Pankaj , Kaushik Ajeet , Kumar Sunil , Thakur Naveen
Published: August 2024

This research focuses on developing environmentally friendly and economically viable Co/Ni-doped hematite nanoparticles (HNPs) through both chemical and green synthesis methods and evaluated their potential for biomedical and environmental applications. The chemical synthesis employs polyvinylpyrrolidone (PVP), while the green approach utilizes Azadirachta indica (A. indica) leaf extract as a stabilizing agent. Co/Ni-doped HNPs are crystalline size ranging from 14 to 21 nm, morphology analysis revealed that the NPs exhibited a quasi-spherical, with an average particle size ranging from 15.98 to 25.91 nm, and dopants confirmed to contain by the XPS spectra. VSM study explains magnetic parameters, coactivity, residual magnetism, and magnetization. A. indica plants contain quinones, saponins, glycosides, alkaloids, and flavonoids. Characterization of the nanoparticles reveals optimized Co/Ni-doped HNPs with enhanced photocatalytic activity. These nanoparticles exhibit a remarkable 93%–95% degradation of UV-reactive dyes (methyl orange and methylene blue) within 90 min, attributed to structural and surface modifications that improve light absorption and enhance charge separation. The study concludes that green-synthesized Co/Ni-doped HNPs outperform chemically synthesized counterparts as superior photocatalysts. Additionally, antioxidant evaluations using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) assays suggest significant antioxidant capabilities. A high scavenging activity percentage, ranging from 83% to 88%, was observed, which increased with higher concentrations of the synthesized Co/Ni-doped HNPs making these nanoparticles suitable for biomedical and environmental applications that require a magnetic system. In this study, the IC50 values for the antioxidant activity of chemically and green synthesized Co/Ni-doped hematite nanoparticles against the DPPH/NO assay were calculated to be 18.33 μg ml−1 and 16.09 μg ml−1, respectively. The research highlights the multifunctional properties of Co/Ni-doped HNPs, addressing the demand for tailored inorganic magnetic nanoparticles with minimal ecological impact.
Enhancement of energy storage and pyroelectric properties of (Na0.5Bi0.5)TiO3-SrTiO3-BaTiO3 ceramics by addition of (Ba0.9B0.1)TiO3 glass-phase
Authors: Ezzeldien Mohammed , Mohamed W S , Al-Qaisi Samah , Ameen Ismail Gad , Mahmoud Abd El-razek
Published: August 2024

The present study introduces a novel analysis of the effect of the glass phase on the energy storage and the pyroelectric properties of 0.65(Bi0.5Na0.5)TiO3-0.25SrTiO3–0.1BaTiO3 (abbreviate NBT-ST-BT) lead-free ceramics. The glass phase was prepared by melt-quenching of (Ba0.9B0.1)TiO3 (BBT) calcined powder. Different content of BBT glass phase was introduced into the ceramic matrix [(1-x)(NBT-ST-BT)—x(BBT)] (x = 0.0, 2.5, 5, 7.5 and 10%) solid solution. The crystal structure shows rhombohedral and orthorhombic coexistence phases, increasing the R-phase volume fraction by increasing BBT glass content. The grain size was suppressed to a sub-micrometer by increasing the BBT glass amount, denoting the enhanced dielectric breakdown strength (BDS). The most significant recoverable energy storage density (Wrec = 2.5 J cm−3) with the highest energy storage efficiency (η ∼ 87%) has been obtained at 200 kV cm−1 of BBT 5%. The variation in Wrec of the optimum sample is less than 4% from 25 °C to 150 °C, indicating the high thermal stability of energy storage properties. The pyroelectric coefficient (PE) was estimated using an approximate numerical method of differentiating remnant polarization Pr concerning temperature. Adding the BBT glass phase enhanced the pyroelectric properties and figure of merit (FOM). The FOM increased from 7 × 10−10 to 8 × 10−10 C/cm2. °C at T = 150 °C when glass content increased from 0.0 to 0.1. These results prove that the addition of the BBT glass phase resolves the difference between high energy storage properties and lower sintering temperatures of ceramic materials, enhancing the pyroelectric properties for practical applications.
On relativistic hydrodynamics: bernoulli process equations
Authors: Güémez J , Mier J A
Published: August 2024

A relativistic covariant description of a Bernoulli process is presented in terms of a set of two fundamental equations: Newton’s second law and the first law of thermodynamics. The set is first obtained in the rest frame of the process S, then in a frame

S

¯

moving at a constant velocity relative to S. It is shown that the set is covariant under Lorentz transformation, and reduces to the classical equations at the low-speed limit.
Coherent superposition of states in multi-state systems using adiabatic pulses split by a phase jump
Authors: Faraji Tohid , Amniat-Talab Mahdi , Saadati-Niari Maghsoud
Published: August 2024

The generation of arbitrary preselected coherent superposition of states in multi-state systems using adiabatic pulses split by a phase jump has been investigated. We consider a linkage pattern that includes a ground state and N excited states so that the ground state is coupled to the excited states using N pulses with a chirped detuning. In this scheme, time-dependent Rabi frequencies and detuning are used in two steps, and in each step, it is assumed that the Rabi frequencies have the same time dependence. Also, the Rabi frequencies in the second step have a phase jump compared to the first step, and the amount of this phase jump is the same for all pulses. It is shown that by properly adjusting the amount of phase jump in the second step and also the maximum value of Rabi frequencies in both steps, an arbitrary coherent superposition of all states can be created. In this study, the maximum values of Rabi frequencies and detuning are considered to be large enough to establish the adiabatic passage condition, and it is numerically shown that this scheme is insensitive to the change of the maximum value of Rabi frequencies and detuning.
A novel reduced-order model reference adaptive control approach with high-frequency oscillation suppression
Authors: Tian Tingting , Hou Xiaorong , Yan Fang
Published: August 2024

High-frequency oscillations may occur in the control signal when the adaptive gain is too large, which will adversely affect the robustness of the model reference adaptive control (MRAC) law and potentially induce system instability. To tackle this challenge, we introduce a reduced-order MRAC approach based on a modified scalar update law that includes a modification term to filter out high-frequency content for the multi-input multi-output (MIMO) nonlinear dynamical systems. This modification significantly reduces the high-frequency oscillations, allowing a controller with a high adaptive gain to achieve fast adaptation. In addition, with this reduced-order adaptive control approach, only two parameters need to be updated online, thus substantially reducing the overall computation burden. Furthermore, we demonstrate that the proposed reduced-order MRAC approach guarantees the Lyapunov asymptotic stability of the system error dynamics. Simulation results are conducted to validate the electiveness of the proposed method.
Impact of rotation on a micro-elongated thermoelastic solid subjected to a load from an overlying liquid layer according to various theories
Authors: Othman Mohamed IA , Eraki Ebtesam EM , Ismail Mohamed F
Published: August 2024

The objective of this study is to examine how the presence of a fluid layer affects thermoelastic behavior of a micro-elongated solid undergoing rotation utilizing the coupled theory (CT) doesn’t contain any relaxation times, the Lord-Shulman (L-S) theory also the model of duple-phase-lag (DPL). Normal mode analysis has been utilized to transform partial differential equations to ordinary differential equations. Subsequently, numerical computations have been performed, and the outcomes have been visualized through graphical representation. In both with and without rotation, a comparison is made among the coupled theory, the (L-S) theory, and the (DPL) model. It is watched that rotation significantly impacts all physical quantities, demonstrating a substantial influence.
Novel CdFe2O4 nanoparticles facile synthesis and their applications towards practical ammonia detection: an effect of annealing
Authors: Shkir Mohd , Ahmad Nafis , Alshahrani Thamraa , Ahmad Zubair , AlFaify S
Published: August 2024

Cadmium ferrite (CdFe2O4) nanoparticles were synthesized via a simple co-precipitation method, and the effect of annealing temperature over the prepared samples’ structural, morphological, and optical properties was analyzed by varying the temperatures 700, 800, and 900 °C. The x-ray diffraction (XRD) studies revealed that the prepared samples are highly crystalline in nature and belong to a cubic spinel crystal structure, and the crystallite size increases from 32 to 59 nm with respect to the increasing temperature. The surface morphology of the ferrite samples showed the uniformly distributed highly agglomerated particles with larger voids for the ferrite nanoparticles annealed at 900 °C. Optical properties of the prepared CdFe2O4 samples were carried out by diffused reflectance spectroscopy (DRS) and the optical band gap of the samples were found to be 2.57, 2.55 and 2.53 eV. The Vibrating sample magnetometer (VSM) studies at room temperature showcased that the nanoparticle samples possess ferromagnetic behavior, and the magnetization (Ms), Coercivity (Hc), and Retentivity (Mr) values were found to be 27.5 × 10−3 emu g−1, 237.60 Oe, and 1976 × 10−6 emu/g for the CdFe2O4 sample annealed at 900 °C. The gas sensing studies were carried out with the presence of target gas ammonia, and its significant sensing parameters such as gas responsivity (S%), rise time, and recovery times were determined, and these values of CdFe2O4 samples annealed at 900 °C were observed to be 1610%, 7.1 s, and 2.2 s. Our findings strongly suggest that the CdFe2O4 samples annealed at 900 °C hold significant promise as a multifunctional material, particularly in gas-sensing applications. This potential opens an exciting avenue for further research and development.
Design and performance analysis of a novel miniaturized band-stop filter for band rejection in Sub-6 GHz 5G spectrum
Authors: Kiouach Fatima , El Ghzaoui Mohammed , Das Sudipta , Islam Tanvir , Ali Wael
Published: August 2024

This paper introduces an innovative band stop filter specifically designed to reject a sub-6GHz band within the 5 G spectrum. Fabricated on an FR4 substrate with a relative permittivity of 4.4, the filter incorporates a defected ground structure (DGS) and features very compact dimensions of 19 mm × 11 mm × 0.8 mm. The filter design is performed using the High Frequency Structure Simulator (HFSS). Besides, the filter’s equivalent circuit is modeled using the ANSYS circuit editor. A parametric study has been conducted to identify the optimal parameters for the filter’s form and size. The proposed filter exhibits a rejected band of 1.42 GHz, spanning from 2.3 GHz to 3.72 GHz, with a center frequency of 3.18 GHz. Within the rejected band, the S21 value is less than −21.36, and the stop band fractional bandwidth (FBW) is 44.65%. Additionally, the filter demonstrates a negative group delay (NGD) characteristic in the frequency range of 2.97 GHz to 3.35 GHz, with a measured NGD time of −0.42 ns, and a quality factor equal to 2.24. These results underscore the filter’s suitability for applications utilizing frequencies below 2 GHz and above 3 GHz, ensuring efficient functionality.
Solving system of nonlinear Abel’s integral equations in frequency domain
Authors: Majidi Reza , Dastmalchi Farhad , Jahangirirad Mohammad
Published: August 2024

In this paper, we solve both linear and nonlinear systems of Abel’s integral equations by combining the Laplace transform with Bernstein polynomials. In the proposed approach, the unknown functions are approximated using Bernstein polynomials. The Laplace transform is then applied to convert the equations from the time domain to the frequency domain. This results in a nonlinear system in terms of unknown coefficients, which is solved using Newtons iterative method. The unknown function is thus approximated. To illustrate the efficacy of the proposed method, we present detailed analytical and numerical examples.
Predicting the dynamic behavior of soliton transmission in two ultra-short optical pulses based on improved physics-informed neural network
Authors: Wang Xuan , Xie Xiyang
Published: August 2024

In this manuscript, we construct physics-informed neural network and improved physics-informed neural network by modifying the loss function, for predicting the dynamic behaviors of bright-bright single-peak solitons, bright-bright double-peak solitons and dark-bright single-peak solitons for the coupled Sasa-Satsuma equations, which depict the characteristics of two ultra-short pulses with the third-order dispersion, stimulated Raman scattering effects and self-steepening propagating simultaneously in birefringent or dual-mode fibers. Firstly, the physics-informed neural network, which is a standard model for managing the soliton prediction, is improved to a double-layer structure, to forecast the bright-bright single-peak solitons. When predicting the bright-bright double-peak solitons and dark-bright single-peak solitons, we find that the above model does not learn the dynamics of solitons, so we add the end-time conditions as the constraints according to the motion characteristics of dynamic solitions. At the same time, considering the complex boundary conditions of the dark solitons, we modify the boundary conditions in the loss function of improved physics-informed neural network for predicting bright-dark solitons. By capturing instantaneous plots at three different times and comparing the predicted values with the exact solutions, it shows that the improved physics-informed neural network is effective. Furthermore, we select the appropriate number of iterations according to the comparison of training error and training time to improve the accuracy of the model.
Realization of meter-scale and high-density of charged particles by surface dielectric barrier discharge
Authors: Zhang Ming , Fu Qixiong , Li Chuan , Li Dingchen , Pan Yuan
Published: August 2024

Utilizing low-temperature plasma for the collection or removal of airborne particles presents a technology with significant potential applications. At atmospheric pressure, dielectric barrier discharge (DBD) is distinguished by its simplistic structure and safe, stable discharge properties. However, the majority of existing research on DBD devices concentrates on small-scale environments, with a notable absence of studies addressing the achievement of high-density diffusion of charged particles in expansive spaces. This study accomplishes the diffusion of high-density (exceeding 1 × 106 cm−3) ions over a meter-scale area through the combination of pulsed surface dielectric barrier discharge (SDBD) and a fan. The study details the impacts of various electrical (frequency, pulse width) and structural (electrode spacing distance, number of high voltage electrodes, dielectric thickness) parameters on ion generation. Experimental results demonstrate that an increase in frequency and pulse width positively influences ion concentration. Reducing the spacing distance between high voltage electrodes and augmenting the number of electrodes results in discharge suppression, a challenge that can be surmounted by elevating the pulse width and frequency. An expansive electrode spacing distance may lead to a diminished saturation ion concentration. Augmenting the thickness of the dielectric layer can enhance ion concentration by attenuating the uniformity of the discharge and decreasing the velocity of charged particle movement. The findings of this study offer valuable guidance for future applications of electrostatic methods in the large-scale removal of dust, fog, and haze from the air.
Predefined-time multi-switch combination-combination synchronization of fractional-order chaotic systems with time delays
Authors: Hailong Zhang , Ding Zhixia , Wang Liheng
Published: August 2024

In this paper, a predefined time multi-switch combination-combination synchronization (PTMSCCS) of fractional-order (FO) chaotic systems is innovatively investigated, advancing the research of combined synchronization of FO chaotic systems in communication. Meanwhile, to consider the problems that some disturbances may affect the system’s performance in practical applications, uncertainty, external disturbances, and time delays are added to four different FO chaotic systems. A newly designed controller and sliding surface are added to the system’s control so that the system can converge and stabilize in a predefined time. This paper uses the Lyapunov stability criterion to determine the stability of the control system and control theory. The final numerical simulation verifies that the system can achieve predefined time synchronization, proving the system design’s effectiveness.
A comparative study of the microstructure and shape memory behaviour of NiTi, NiTiHf, and Pt-added NiTiHf alloys
Authors: Mohan M S , Ramaiah K V , Saikrishna C N , Banerjee Dipankar
Published: August 2024

The microstructure, substructure, transformation temperature, and recovery ratio of a novel Ni45Pt
5
Ti30Hf20 alloy are reported in the current work. The properties of binary TiNi and ternary TiNiHf alloys are also characterized to establish a comparative basis for shape memory behaviour. The microstructure of the cast structure of Ni45Pt5Ti30Hf20 alloy showed a dendritic matrix and interdendritic eutectic-like mixture, and that of the homogenized structure consisted of martensitic matrix and secondary phase of dark contrast having the composition (Ti+Hf)2(Ni+Pt). Pt substitution of Ni in the ternary alloy with 20 at.% Hf by 5 at.% leads to a decrease in the Af, As, Ms, and Mf . Ms and Mf represent the temperatures at which austenite to martensite transformation starts and completes, respectively, while As and Af represent the temperatures at which martensite to austenite transformation starts and completes, respectively. The XRD studies showed that the structure of martensite is B19′ and TEM studies showed that the substructure of martensite in Pt modified NiTiHf alloy is similar to that of ternary NiTiHf alloy. The shape memory recovery of the Pt-modified alloy is similar to the ternary alloy at higher strength levels. The recovery ratio determined using Vickers indentation is compared with that determined using compression tests to provide an efficacy of small volume tests for screening of these alloys.