bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal evolution and stability analysis of phenomenologically emergent dark energy model
Authors: John Rosemin , Sarath N. , Mathew Titus K.
Published: August 2023

The phenomenologically emergent dark energy (PEDE) model is a varying dark energy model with no extra degrees of freedom proposed by Li and Shafieloo (Astrophys J 883(1):L3, 2019) to alleviate the Hubble tension. The statistical consistency of the model has been discussed by many authors. Since the model depicts a phantom dark energy that increases with redshift, its cosmic evolution, particularly during the late phase, must be examined. We discover that the model’s Hubble and deceleration parameters display unusual behaviour in the future, which differs from $$\varLambda $$
Λ
CDM cosmology. We find the model also follows a distinct evolution in the statefinder plane. The phantom nature of the model leads to the violation of the null energy condition and a decrease in horizon entropy. The asymptotic future epoch also seems to be unstable based on our dynamical system analysis as well as the stability analysis based on dark energy sound speed.
Effect of Action Units, Viewpoint and Immersion on Emotion Recognition Using Dynamic Virtual Faces
Authors: Vicente-Querol Miguel A. , Fernández-Caballero Antonio , González Pascual , González-Gualda Luz M. , Fernández-Sotos Patricia , Molina José P. , García Arturo S.
Published: August 2023

Facial affect recognition is a critical skill in human interactions that is often impaired in psychiatric disorders. To address this challenge, tests have been developed to measure and train this skill. Recently, virtual human (VH) and virtual reality (VR) technologies have emerged as novel tools for this purpose. This study investigates the unique contributions of different factors in the communication and perception of emotions conveyed by VHs. Specifically, it examines the effects of the use of action units (AUs) in virtual faces, the positioning of the VH (frontal or mid-profile), and the level of immersion in the VR environment (desktop screen versus immersive VR). Thirty-six healthy subjects participated in each condition. Dynamic virtual faces (DVFs), VHs with facial animations, were used to represent the six basic emotions and the neutral expression. The results highlight the important role of the accurate implementation of AUs in virtual faces for emotion recognition. Furthermore, it is observed that frontal views outperform mid-profile views in both test conditions, while immersive VR shows a slight improvement in emotion recognition. This study provides novel insights into the influence of these factors on emotion perception and advances the understanding and application of these technologies for effective facial emotion recognition training.
A unified approach to infinitesimal freeness with amalgamation
Authors: Tseng Pei-Lun
Published: August 2023

In this paper, we consider the infinitesimal freeness in the operator-valued framework, and we show that the operator-valued infinitesimal (OVI) free independence is equivalent to the operator-valued free independence over an algebra of [Formula: see text] upper triangular matrices. We introduce the notion of OVI cumulants and investigate its properties, and we then deduce that the OVI freeness is equivalent to the vanishing of our mixed cumulants. Moreover, we derive the formula for obtaining the free additive and multiplicative convolutions within the realm of OVI freeness.
Evolution of transport under cumulative damage in metro systems
Authors: Eraso-Hernandez L. K. , Riascos A. P. , Michelitsch T. M. , Wang-Michelitsch J.
Published: August 2023

One dominant aspect of cities is transport and massive passenger mobilization which remains a challenge with the increasing demand on the public as cities grow. In addition, public transport infrastructure suffers from traffic congestion and deterioration, reducing its efficiency. In this paper, we study the capacity of transport in 33 worldwide metro systems under the accumulation of damage. We explore the gradual reduction of functionality in these systems associated with damage that occurs stochastically. The global transport of each network is modeled as the diffusive movement of Markovian random walkers on networks considering the capacity of transport of each link, where these links are susceptible to damage. Monte Carlo simulations of this process in metro networks show the evolution of the functionality of the system under damage considering all the complexity in the transportation structure. This information allows us to compare and classify the effect of damage in metro systems. Our findings provide a general framework for the characterization of the capacity to maintain the transport under failure in different systems described by networks.
Enhanced robustness of flow networks with dependency groups
Authors: Zhou Lin , Qi Xiaogang , Zheng Mingfa , Liang Fangchi
Published: August 2023

Dependency links represent the relationships between network nodes that have an interactive impact on cascading failures caused by load fluctuation in the network. However, existing research mainly focuses on load fluctuation’s failure mechanisms without considering the dependency links of nodes and their cascading prevention mechanisms in reality. This study addresses the cascading prevention problem in networks when dependency links and connectivity links operate together. It proposes a hybrid cascading failure model based on the dependency relationships, load fluctuation and reinforced nodes. Furthermore, it provides four reinforced nodes’ strategies that leverage static and local information characteristics of network nodes. These strategies help the network to perform its function and prevent cascading failures effectively. The study considers actual situations where overloaded nodes can still maintain their function. To measure the overload ability and the uncertainty of node failure, the authors used the overload coefficient parameter and the failure probability. Additionally, the impact of the dependency group’s size on the network robustness is explored. Simulation results on BA and ER networks and two actual networks show that reinforced nodes’ strategies provide significant support in keeping the network away from abrupt collapses.
Realizing stochastic fixed-time synchronization between two nonlinear chaotic finance systems
Authors: Wu Jie , Pan Xiaohong , Wu Kexing , Wang Xiaofeng
Published: August 2023

The issue of stochastic fixed-time synchronization (SFxS) between two nonlinear chaotic finance systems (CFSs) in noisy environment is addressed by this investigation. Two novel strategies, including the adaptive and fixed-time control, are integrated organically, which steers the CFSs to realize synchronization within a fixed-time, and meanwhile the controlling gains can be updated by the designed adaptive law. Particularly, the designed adaptive fixed-time controlling (AFC) scheme is differentiable, so that the chattering phenomenon can be alleviated and even eliminated effectively. Furthermore, by the stochastic Lyapunov stability analysis, the sufficient criterion is derived for realizing the SFxS of CFSs, and the upper-bound expectation of settling-time (UET) is estimated as well. At last, the numerical experiments are arranged to verify the correctness and feasibility of analytical results, the influence of noisy perturbation on the convergence rate is uncovered, and the interesting similar Dragon–King events are observed.
Collective dynamics of polarized spin-half fermions in relativistic heavy-ion collisions
Authors: Singh Rajeev
Published: August 2023

Standard relativistic hydrodynamics has been successful in describing the properties of the strongly interacting matter produced in the heavy-ion collision experiments. Recently, there has been a significant theoretical advancement in this field to explain spin polarization of hadrons emitted in these processes. Although current models have successfully explained some of the experimental data based on the coupling between spin polarization and vorticity of the medium, they still lack a clear understanding of the differential measurements. This is commonly interpreted as an indication that the spin needs to be treated as an independent degree of freedom whose dynamics is not entirely bound to flow circulation. In particular, if the spin is a macroscopic property of the system, in equilibrium its dynamics should follow hydrodynamic laws. Here, we develop a framework of relativistic hydrodynamics which includes spin degrees of freedom from the quantum kinetic theory for Dirac fermions and use it for modeling the dynamics of matter. Following experimental observations, we assume that the polarization effects are small and derive conservation laws for the net baryon current, the energy–momentum tensor and the spin tensor based on the de Groot–van Leeuwen–van Weert definitions of these currents. We present various properties of the spin polarization tensor and its components, analyze the propagation properties of the spin polarization components, and derive the spin-wave velocity for arbitrary statistics. We find that only the transverse spin components propagate, analogously to the electromagnetic waves. Finally, using our framework, we study the space–time evolution of the spin polarization for the systems respecting certain space–time symmetries and calculate the mean spin polarization per particle, which can be compared to the experimental data. We find that, for some observables, our spin polarization results agree qualitatively with the experimental findings and other model calculations.
Investigation of Bd(s)∗→Dd+(Ds+)τ−v̄τ decays in W′ model and scalar leptoquark model
Authors: Mahata S. , Mandal M. , Biswas S. , Biswas A. , Sahoo S.
Published: August 2023

Inspired by recent anomalies associated with the [Formula: see text] hadron decays, a theoretical investigation on [Formula: see text] decays has been performed in [Formula: see text] model and scalar leptoquark model. To implicate these models, new coupling parameters are fixed by [Formula: see text] fitting using recent experimental results from [Formula: see text] transition as constraints. We have estimated branching fraction, lepton flavor universality (LFU) parameter, forward–backward asymmetry and lepton-spin asymmetry in the standard model (SM) as well as above two new physics (NP) models. Except lepton-spin asymmetry, significant deviations from the SM predictions are observed in [Formula: see text] model for both channels. In comparison to other observables, lepton-spin asymmetry shifts slightly from the SM in scalar leptoquark model. Our results may be helpful to the experimental communities to explore these decays and [Formula: see text] boson and leptoquark at the colliders.
Stochastic quantization and holographic Wilsonian renormalization group of scalar theory with generic mass, self-interaction and multiple trace deformation
Authors: Kim Gitae , Chae Ji-Seong , Shin WooCheol , Oh Jae-Hyuk
Published: August 2023

We explore the mathematical relationship between holographic Wilsonian renormalization group (HWRG) and stochastic quantization (SQ) of scalar field theory with its generic mass, self-interaction and [Formula: see text]-multiple-trace deformation on the [Formula: see text]-dimensional conformal boundary defined in AdS[Formula: see text] space–time. We understand that once we define our Euclidean action, [Formula: see text] as [Formula: see text], then the stochastic process will reconstruct the HWRG data via solving Langevin equation and computing stochastic correlation functions. The [Formula: see text] is given by [Formula: see text], where [Formula: see text] is the boundary counter term and [Formula: see text] is the boundary deformation which gives a boundary condition. In our study, we choose the boundary condition adding (marginal)[Formula: see text]-multiple-trace deformation to the holographic dual field theory. In this theory, we establish maps between fictitious time, [Formula: see text] evolution of stochastic [Formula: see text]-point, ([Formula: see text])-point correlation functions and the (AdS)radial, [Formula: see text] evolution of [Formula: see text]-multiple-trace and ([Formula: see text])-multiple-trace deformations, respectively, once we take identifications of [Formula: see text] and between some of the constants appearing in both sides.
The constrained dispersionless BKP hierarchy and its additional symmetries
Authors: Tian Kelei , Li Song , Yi Ge , Xu Ying
Published: August 2023

In this paper, the constrained dispersionless BKP hierarchy are given by restricting the formal Laurent series [Formula: see text] of the dispersionless BKP hierarchy to [Formula: see text]. Its additional symmetries are given by introducing vital formal Laurent series [Formula: see text]. The additional flows form the nonabelian [Formula: see text]-grading Lie algebra. Furthermore, the additional flows acting on [Formula: see text] and [Formula: see text] are presented.
Holographic quantum information and (de)confinement
Authors: Patrascu Andrei T.
Published: August 2023

Analyzing the phenomenon of deconfinement from a holographic point of view, it appears that the brane configuration in the bulk, corresponding to the confinement phase imposes a restriction on the strength of the holographic quantum error correction procedure. This restriction is partially removed when the transition to a deconfined phase occurs. The brane configurations corresponding to the bulk instantons are analyzed and it is shown that they cannot reach the region of the bulk that would ensure maximal error protection in the confinement phase, while keeping non-zero instanton size. In the deconfinement phase on the other side, we have a configuration that allows a higher degree of quantum error protection, still preventing the maximal protection allowed by the holographic principle. This suggests that the strength of quantum error correction codes in QCD systems is fundamentally limited both in confinement and deconfinement phases.
WiFi-Based Lightweight Gesture Recognition for Coal Miners
Authors: Zhang Lei , Liang Xiao , Shan Jiawei , Ran Lingbo , Zhu Yonghong
Published: August 2023

With the advancement of smart mines, the need for gesture recognition for remote interaction between underground workers and machines has become crucial. However, traditional gesture recognition techniques require complex models that are very difficult to be deployed to the edge. To address this challenge, a gesture recognition method based on knowledge distillation is proposed in this study. First, the CSI ratio model is used to eliminate phase error and environmental noise, followed by the application of discrete wavelet transform to eliminate hardware noise interference. Then, the processed data is adaptively segmented using the principal component analysis and local anomaly factor algorithm to eliminate redundant static components. After that the processed CSI data is transformed into images using the relative position matrix method. Finally, knowledge distillation is employed to migrate knowledge from a teacher model to a student model, reducing the number of model parameters. Experiments conducted on the proposed method showed that it can achieve a recognition accuracy of 94.2% for hand gesture detection, which meets the requirement for gesture recognition in the mining industry.
A Lightweight Insulator Detection Methodology for UAVs in Power Line Inspection
Authors: Meng Yue , Tang Yiming , Huang Xiang , Wang Haoyu , Zhu Jie , Tang Wenjuan , Chen Lu
Published: August 2023

The defect of insulators on the power line may lead to the failure of the electric transmission system, which in turn endangers the safe and reliable operation of the whole power system. Therefore, timely and accurate detection of insulators has become a current research hotspot. However, manual inspection cannot guarantee real-time detection and is prone to security accidents. Thanks to the convenience of Unmanned Aerial Vehicles (UAVs), collecting insulator images by UAVs and designing detection algorithms on insulators for real-time and accurate insulator detection have become a practical option. In this paper, considering the poor computing resources of UAVs, a lightweight object detection algorithm, NanoDet, is trained to detect insulators. In addition, to fully utilize the computing resources, the proposed model is segmented. Power-efficient layers are mapped to the central processing units (CPUs) for execution. Experimental results indicate that the proposed model can cut down the power consumption by up to 46.4% without violating the time constraint.
Abnormal User Identification in Substation Area Based on Restricted Ridge Regression Model
Authors: Du Xingang , Zhao Bing , Ge Dehui , Li Yajie
Published: August 2023

The rapid development of the smart grid affects every aspect of people’s lives at all times. Among them, the identification accuracy of power metering anomalies is a serious problem that needs to be solved urgently. To further improve the identification accuracy of power metering anomalies, a user identification method for substation area anomalies is designed based on the restricted ridge regression model. First, a clustering algorithm is designed using high-frequency voltage data of users in the substation area to conduct phase separation and terminal branch identification for each user metering point in the substation area. Then establish a substation area energy conservation model equation set, and merge the end branch users based on genetic algorithm clustering results, thereby reducing the unknown quantity dimension. Then, a line resistance-constrained condition is constructed using the topological structure, and the model equation set is solved using quadratic programming based on the constrained ridge regression method to obtain the measurement point error results of users in the substation area. The experimental results show that this recognition method’s clustering effect and recognition accuracy are high, with a recognition rate of 98.21%. It can be seen that this abnormal user identification method has application value.
End-to-End Dual-Stream Transformer with a Parallel Encoder for Video Captioning
Authors: Ran Yuting , Fang Bin , Chen Lei , Wei Xuekai , Xian Weizhi , Zhou Mingliang
Published: August 2023

In this paper, we propose an end-to-end dual-stream transformer with a parallel encoder (DST-PE) for video captioning, which combines multimodal features and global–local representations to generate coherent captions. First, we design a parallel encoder that includes a local visual encoder and a bridge module, which simultaneously generates refined local and global visual features. Second, we devise a multimodal encoder to enhance the representation ability of our model. Finally, we adopt a transformer decoder with multimodal features as inputs and local visual features fused with textual features using a cross-attention block. Extensive experimental results demonstrate that our model achieves state-of-the-art performance with low training costs on several widely used datasets.
Shadows near supermassive black holes: From a theoretical concept to GR test
Authors: Zakharov Alexander F.
Published: August 2023

General relativity (GR) passed many astronomical tests but in majority of them GR predictions have been tested in a weak gravitational field approximation. Around 50 years ago a shadow was introduced by Bardeen as a purely theoretical concept but due to an enormous progress in observational and computational facilities this theoretical prediction has been confirmed and the most solid argument for an existence of supermassive black holes in Sgr A* and M87* has been obtained.
Thermodynamics as a tool for (quantum) gravitational dynamics
Authors: Alonso-Serrano Ana , Liška Marek
Published: August 2023

The thermodynamics of local causal horizons has been shown to imply gravitational dynamics. In this essay, we discuss the principles underlying this observation, and its significance in our understanding of (quantum) gravity. We also show why the local thermodynamic methods cannot by themselves recover general relativity. Instead, they lead to the so-called Weyl transverse gravity. Because of this, local thermodynamic approaches avoid huge vacuum energy contributions to the cosmological constant. They even suggest a possible source for its small observed value. We also outline a way in which thermodynamics allows us to study low energy quantum gravitational effects. We arrive at quantum corrections to the gravitational equations which are suppressed by the Planck length squared.
Quantum absorption properties of Kerr–Newman–de Sitter black hole
Authors: Polo Chiging Lasa , Singh Heisnam Shanjit
Published: August 2023

In this work, we utilize the Wentzel–Kramers–Brillouin (WKB) approximation to determine the Hawking temperature corresponding to the Kerr–Newman–de Sitter (KNdS) spacetime. Specifically, we calculate the low frequency absorption cross-section for the KNdS black hole in a charged scalar field and analyzed its dependence on the characteristics of the black hole. Through our research, we have established a correlation between the absorption cross-section ([Formula: see text]) and the Hawking temperature ([Formula: see text]) of the black hole, demonstrating an inverse proportionality between the two quantities. Furthermore, we also deduce the absorption cross-sections for Kerr–de Sitter, Reissner–Nordstrom–de Sitter, Schwarzschild–de Sitter and Schwarzschild black holes, and compare them with previously obtained results. The validity of our findings is demonstrated by these comparisons.
Minimal model-dependent constraints on cosmological nuisance parameters and cosmic curvature from combinations of cosmological data
Authors: Dinda Bikash R.
Published: August 2023

The study of cosmic expansion history and the late time cosmic acceleration from observational data depends on the nuisance parameters associated with the data. For example, the absolute peak magnitude of type Ia supernova associated with the type Ia supernova observations and the comoving sound horizon at the baryon drag epoch associated with baryon acoustic oscillation observations are two nuisance parameters. The nuisance parameters associated with the gamma-ray bursts data are also considered. These nuisance parameters are constrained by combining the cosmological observations using the Gaussian process regression method with minimal model dependence. The bounds obtained in this method can be used as the prior for the data analysis while considering the observational data accordingly. Along with these nuisance parameters, the cosmic curvature density parameter is also constrained simultaneously. We find that the constraints on the cosmic curvature density parameter show no significant deviations from a flat Universe.
Rotational spectroscopies of reflection-asymmetric nuclei within particle rotor model
Authors: Wang Yuanyuan , Zhang Shuangquan
Published: August 2023

The rotational spectroscopic properties of reflection-asymmetric nuclei investigated by the reflection-asymmetric axial or triaxial particle rotor model are briefly reviewed. The status of observations of the alternated parity bands in even–even nuclei and the parity doublet bands in odd-[Formula: see text] and odd–odd nuclei for the [Formula: see text] mass region are summarized. The reflection-asymmetric axial particle rotor model has been used to systematically describe the parity doublet bands of the odd-[Formula: see text] nuclei in this region. With the triaxial degree of freedom included, the reflection-asymmetric triaxial particle rotor model shows the ability to study the multiple chiral doublet bands with octupole correlations and explore the possible chirality-parity quartet bands.
Asymptotic normalization coefficient for6He+p→7Li from the proton transfer d(6He,7Li)n reaction
Authors: Tursunmakhatov K. I. , Ikromkhonov E. Sh.
Published: August 2023

The main purpose of this work is to determine values of the asymptotic normalization coefficients for the virtual decays6He+p[Formula: see text]Li(g.s.) and6He+p[Formula: see text]Li(0.48[Formula: see text]MeV). For this purpose, the recently measured experimental differential cross-section of the proton transfer reaction d(6He,7Li)n has been analyzed. The modified distorted wave born approximation is used to determine the values of the asymptotic normalization coefficients. The peripheral character of this reaction has been tested. It has been shown that this reaction is peripheral. New values of the asymptotic normalization coefficients for the virtual decays6He+p[Formula: see text]Li(g.s.) and6He+p[Formula: see text]Li(0.48[Formula: see text]MeV) with their uncertainties have been obtained.
kn-out-of-n: F System with a Random Number of Components
Authors: Abada Lamia , Boushaba Mahmoud
Published: August 2023

k-out-of-n systems are among the most important models in practical engineering, they have been extensively studied in the past decades. The system fails if and only if there exist at least k failed components. Generally these systems are considered with a fixed number of components. However, many systems have a variable number of components which can be considered a random variable. In the present paper, we studied the [Formula: see text]-out-of-[Formula: see text]: F system, we assume that the system has an unknown number of components, and we search for this number, assuming it is a random variable, by optimizing the system’s cost.

This variable is supposed following a power series distribution such as geometric, Poisson and logarithmic distributions. This work discusses the case where [Formula: see text] for optimization problems. Optimal replacement policies, the optimal number of components and the optimal replacement time are determined to make maintenance and avoid failure, this will minimize the mean cost rates. We started with the case of constant number of components, where we give real and approximate values of the MTTF, optimal number of components and optimal replacement time, then, we considered variable number of components, where the results are compared to the constant case. Numerical examples are also given to illustrate our results.
Numerical Study of the Hydride Embrittlement in Zirconium Alloy using XFEM
Authors: Jha Anjali , Duhan Neha , Singh I. V. , Mishra B. K. , Singh Ritu , Singh R. N.
Published: August 2023

A numerical model for hydride embrittlement in Zirconium alloy (Zr–2.5Nb) is developed utilizing the extended finite element method (XFEM). Hydride embrittlement reduces the ductility and failure time of a metal/alloy. During hydride embrittlement, stress-directed hydrogen diffusion, metal-hydride phase transformation, mechanical deformation, and hydride precipitation occur simultaneously. The present model incorporates all these processes and is able to predict the hydrogen concentration and the hydride fraction distribution under any externally applied stress field. In this work, both the steady and transient hydrogen diffusion cases are evaluated. Further, the XFEM is utilized to develop a model of hydride embrittlement in the presence of a crack. The first step of the hydride embrittlement process is the diffusion of hydrogen. According to Fick’s law of diffusion, hydrogen diffusion is directly dependent on hydrostatic stresses and hydrogen concentration gradient under external stresses. The next step is the hydride precipitation in hydride embrittlement, where the expansion of material takes place that changes the hydrostatic stress field. Thus, studying the effect of precipitation of hydride on hydrostatic stresses is essential. Moreover, the process of hydride embrittlement is highly influenced by residual stresses in the structure. Hence, the effect of residual stress present in the zirconium alloy pressure tube (PT) is also evaluated. The results indicate that the residual tensile stresses contribute to the growth of hydride, which will reduce the material failure time.
Hygrothermally-Induced Vibration Analysis of Porous FGM Rectangular Mindlin Plates Resting on Elastic Foundation
Authors: Ansari R. , Zargar Ershadi M. , Laskoukalayeh H. Akbardoost , Faraji Oskouie M. , Rouhi H.
Published: August 2023

The nonlinear vibration response of rectangular plates made of functionally graded porous materials (FGPs) induced by hygrothermal loading is investigated in this article using a numerical approach. The effect of elastic foundation on the vibrations is taken into account according to the Winkler–Pasternak model. Hygroscopic stresses produced due to nonlinear rise in moisture concentration are also considered. The temperature-dependent material properties of plate are computed based on the modified Voigt’s rule of mixture and Touloukian experiments for even and uneven distribution patterns of porosity. Within the framework of the first-order shear deformation plate theory and von-Kármán nonlinearity, Hamilton’s principle is utilized in order to derive the equations of motions. To achieve the temporal evolution of maximum lateral deflection of hygrothermally-induced plates, the generalized differential quadrature (GDQ) and Newmark integration methods are employed. Selected numerical results are presented to study the influences of temperature distribution, porosity volume fraction, moisture concentration, geometrical parameters, elastic foundation parameters and FG index on the geometrically nonlinear vibrations of FG porous plates with various boundary conditions.
Vibration Analysis of a Plate Embedded or Attached with Acoustic Black Hole Using a Virtual Spring Energy Method
Authors: Wan Zhiwei , Zhu Xiang , Li Tianyun , Guo Wenjie , Dai Wei
Published: August 2023

Acoustic black hole (ABH) with the power-law profile has the advantages of strong designability and vibration suppression. This study provides a novel virtual spring energy method (VEM) to solve the vibration characteristics of a plate embedded or attached with acoustic black hole. Firstly, the virtual springs in this study can deal with boundary conditions, continuity conditions, and periodic conditions. After solving the kinetic and potential energy of a plate cell embedded with acoustic black hole, the periodic structure’s kinetic and potential energy need not be calculated repeatedly. The method is verified by the finite element method. Secondly, to overcome the stiffness reduction owing to the varying thickness of ABH in the primary bearing structure, a composite ABH structure called “Plate–ABH” is proposed, in which a damping layer is designed with an ABH profile and attached to the primary plate structure. The two layers connect each other through the virtual springs. The vibration characteristics of the composite ABH plate are given by employing the VEM. The composite ABH structure shows strong damping ability and lighter weight compared with a plate attached with the uniform thickness damping layer. Plate–ABH can be effectively used in the engineering of vibration reduction.
Damage Assessment of Segmental Concrete Beams with Different Types of Joints and Prestressed External Tendons
Authors: Li Han , Li Jun , Hao Hong , Peng Zhen
Published: August 2023

Precast segmental beams with prestressed external tendons have become increasingly common in bridge constructions owing to the merits of high-quality control and fast onsite construction with minimum environmental impact. Due to the nonlinear characteristics of the dynamic behavior of these segmental beams associated to the joint opening, the traditional condition monitoring and damage assessment methods based on vibration parameters either in time or frequency domain using the linear theory are unsuitable. To overcome this challenge, this paper proposes a damage assessment method through analyzing nonlinear structural dynamic responses for monitoring the conditions of segmental beams with different joint types and prestressed external tendons. Two damage indices are proposed to identify the occurrence of damage and to qualitatively indicate the damage severity. In the proposed approach, the measured dynamic responses of the segmental concrete beams under hammer impact are first adaptively decomposed into a finite number of mono-components by using variational mode decomposition (VMD) technique. Then, the instantaneous frequencies of the decomposed mono-components from the dynamic responses are obtained by conducting the Hilbert transform. Two damage indicators are defined for the damage assessment and for the identification of the damage location, respectively. Three four-span segmental beams with different types of joints (i.e. dry joints or epoxy joints) and prestressing tendon types (i.e. steel and carbon fiber reinforced polymer tendons) were constructed and tested under five loading levels with different damage severities. The feasibility and accuracy of the proposed approach are verified by comparing the identification results with the secant and initial stiffness extracted from the load–deflection curves at different loading levels. The effectiveness of these two damage indicators is also validated with the structural conditions observed in the tests. The results show that the proposed approach can successfully identify damage in segmental concrete beams.
Nonlinear Vibration and Stability Analysis of Rotating Functionally Graded Piezoelectric Nanobeams
Authors: Li H. N. , Wang W. , Lai S. K. , Yao L. Q. , Li C.
Published: August 2023

Presented herein is an investigation for the nonlinear vibration and stability analysis of rotating functionally graded (FG) piezoelectric nanobeams based on the nonlocal strain gradient theory. The present model can be regarded as a simplified version for the rotating nanowire of biomechanical nanogenerators. The Hamilton principle is used to derive nonlinear equations of motion and their related boundary conditions, which are then discretized to form a set of algebraic equations. Accordingly, the nonlinear vibration frequencies and buckling loads of the nanobeams can be determined by an iterative method. A parametric study of rotational velocity, nonlocal parameter, material length parameter, power-law index, and electrostatic voltage on the dynamic stability behavior of such nanobeams is also presented. In the cantilever case, increasing the nonlocal parameter and material length parameter can result in a stiffness-hardening effect that is unaffected by rotational velocity and the material length parameter to nonlocal parameter ratio. Yet, this has not been reported previously. More importantly, incorporating the effect of geometric nonlinearity on the dynamic responses and stability results of the nanobeams is indispensable. In particular, new observations for the coupling effect of vibration amplitude and power-law index on the electric potential effect are useful for the design of rotating microelectromechanical devices.
A Hybrid Method for Vehicle–Track Coupling Dynamics by Analytical and Finite Element Combination Technique
Authors: Xin Tao , Wang Sen , Wang Pengsong , Yang Yi , Dai Chuanqing
Published: August 2023

Globally, rail transit is developing toward higher speeds, larger axle weights, and greater environmental friendliness. The more and more complex wheel–rail interaction will result in the dynamic responses of vehicles, tracks and other structures needing more in-depth theoretical research. However, most existing models for dynamic simulations of the vehicle–track coupling system need to extend the model on both sides of the concerned region to eliminate the boundary effect. To a certain extent, this kind of process method increases the computational effort. To overcome this disadvantage, a hybrid model combined with the analytical method and finite element method was proposed. The moving support system (including transition nodes) was specially established referring to the analytical solution of rail deflection based on the Winkler elastic foundation beam theory to realize the combination of the two methods. Two examples were presented to verify the stability and accuracy of the proposed model. The comparison results show that simulation results of vertical wheel–rail forces and track vibrations are almost consistent with the existing model. Furthermore, the calculation efficiency was discussed and certificated under different long-marshalling trains, with an obvious speedup factor that could be more than 2.5 for 16-marshalling train. The proposed model has a wide application prospect in the vehicle–track coupling analysis of long-marshalling trains, especially for heavy haul railways with hundreds of vehicles.
Analysis on Thermo-Electrical Principal Parametric Resonance of an Axially Moving Piezoelectric Thin Plate
Authors: Li Zhe , Li Yi , Hu Yuda
Published: August 2023

In this paper, principal parametric resonance of an axially moving piezoelectric rectangular thin plate under thermal and electric field is investigated. Based on Kirchhoff–Love plate theory and Von Karman theory, the transverse vibration differential equation of a piezoelectric rectangular thin plate under thermal and electric field is derived by using Hamilton’s principle. The dimensionless vibration equation of piezoelectric rectangular thin plate with parametric excitations is discretized by Galerkin’s method. Then, the multiple scales method is applied to derive amplitude-frequency response equation and the stability conditions of the steady-state solution are obtained by Lyapunov stability theory. Numerical method is used to find the influences of specific parameters on the vibration performance and stability of the system. Based on the global bifurcation diagram and corresponding response diagram, the influences of bifurcation control parameters on the nonlinear dynamic characteristics of the system are discussed. Numerical results illustrate that the system amplitude frequency characteristic curve presents soft spring characteristics. There are periodic and chaotic motions with the increase of velocity and the central temperature difference, and the decrease of plate thickness and velocity will result in the decrease of chaotic threshold. The results also show that increase the velocity perturbation amplitude can prolong the chaotic motion.
A new generalized inverse for rectangular matrices
Authors: Wang Chengcheng , Zhu Huihui
Published: August 2023

The goal of this paper is to introduce a new generalized inverse, called the MMP-inverse along a matrix. Let [Formula: see text] be the set of [Formula: see text] complex matrices. Given any [Formula: see text] and [Formula: see text], the matrix [Formula: see text] is called MMP-invertible along [Formula: see text] if there exists a matrix [Formula: see text] such that [Formula: see text] and [Formula: see text]. Such an [Formula: see text] is called an MMP-inverse of [Formula: see text] along [Formula: see text]. Some characterizations of the MMP-inverse along a matrix are given by its range and null space. Also, the connection between the MMP-inverse along a matrix and other generalized inverses is investigated. Finally, the formula for the MMP-inverse of matrices is expressed.
On non-counital Frobenius algebras
Authors: Hernandez Amanda , Walton Chelsea , Yadav Harshit
Published: August 2023

A Frobenius algebra is a finite-dimensional algebra [Formula: see text] which comes equipped with a coassociative, counital comultiplication map [Formula: see text] that is an [Formula: see text]-bimodule map. Here, we examine comultiplication maps for generalizations of Frobenius algebras: finite-dimensional self-injective (quasi-Frobenius) algebras. We show that large classes of such algebras, including finite-dimensional weak Hopf algebras, come equipped with a nonzero map [Formula: see text] as above that is not necessarily counital. We also conjecture that this comultiplicative structure holds for self-injective algebras in general.
On the structure of principal series representations of SL2(𝔽̄p)
Authors: Chen Xiaoyu
Published: August 2023

Let [Formula: see text] be a prime number and [Formula: see text] be the algebraic closure of the finite field [Formula: see text] with [Formula: see text] elements. Let [Formula: see text] be an algebraically closed field of characteristic [Formula: see text]. Let [Formula: see text] and [Formula: see text] be the standard Borel subgroup of [Formula: see text]. For any character [Formula: see text] of [Formula: see text], define [Formula: see text], where [Formula: see text] is the group algebra of [Formula: see text]. In this paper, we prove two interesting properties of [Formula: see text]: (a) [Formula: see text] is either of finite length or residually finite; (b) Any nontrivial quotient of [Formula: see text] is finite dimensional.
Dual wavelet frame packets with non-square iterative matrices
Authors: Zhang Zhihua
Published: August 2023

Traditional wavelet frame packets are based on square iterative matrices and frame scaling functions. Since the Fourier transform of frame scaling functions are discontinuous, the resulting wavelet frame packets do not possess time-frequency localization. In this study, we will develop the new construction of wavelet frame packets by using non-square iterative matrices: one is to construct wavelet frame packets directly from known non-GMRA wavelet frames to obtain finer time-frequency structure, the other is based on GMRA wavelet frames constructed from smooth generalization scaling functions, the corresponding quasi-projection formula and fast algorithm are also given.
Effect of Initial Stress and Impedance Boundary in Transversely Isotropic Materials
Authors: Lianngenga R. , Lalvohbika J.
Published: August 2023

This paper aimed at studying the effect of initial stress and impedance boundary surface on the elastic waves propagation in transversely isotropic materials. The governing equations of transversely isotropic materials with initial stress are treated in the [Formula: see text]-plane to obtain the phase velocities of two waves, quasi-longitudinal ([Formula: see text]) and quasi-transverse ([Formula: see text]) waves. The normal mode operation is employed to obtain the expression of the displacement components and stress components. The problem of reflection of incident waves at the impedance boundary of transversely isotropic material is also investigated in the presence of initial stress to obtain the amplitude ratios of reflected waves. The variations of displacement and force stress are illustrated with respect to the axis of propagation by employing amplitude ratio expression. The effect of initial stress and impedance parameters on the expression of displacement and force stress as well as amplitude ratios of transversely isotropic materials are illustrated graphically for a particular model.
Non-Probabilistic Uncertainty and Correlation Propagation Analysis Methods Based on Multidimensional Parallelepiped Model
Authors: Lü Hui , Li Zhencong , Huang Xiaoting , Shangguan Wen-Bin
Published: August 2023

In engineering practice, the uncertainty and correlation may coexist in the input parameters, as well as in the output responses. To address such cases, several methods are developed for the non-probabilistic uncertainty and correlation propagation analysis in this study. In the proposed methods, the multidimensional parallelepiped model (MPM) is introduced to quantify the uncertainty and correlation of input parameters. In the uncertainty propagation analysis, three methods are presented to calculate the interval bounds of output responses. Among the methods, the Monte Carlo uncertainty analysis method (MCUAM) is firstly presented as a reference method, and then the first-order perturbation method (FOPM) is employed to promote the computational efficiency, and the sub-parallelepiped perturbation method (SPPM) is further developed to handle the correlated parameters with large uncertainty. In the correlation propagation analysis, the Monte Carlo correlation analysis method (MCCAM) is proposed based on the MPM and Monte Carlo simulation, which aims to compute the correlation among different output responses. The uncertainty domains between any two responses can also be constructed by the MCCAM. The effectiveness of the proposed methods on dealing with the uncertainty and correlation propagation problems is demonstrated by three numerical examples.
Dynamical profile and multi-stability of ion-acoustic waves with soliton solution arising in plasma physics
Authors: Fatima Samara , Abbas Naseem , Munawar Maham
Published: August 2023

The present exploration studies the dynamical profile, multistability and soliton solution of ion-acoustic waves (IAWs) in plasma physics. The new auxiliary equation approach is implemented to compute a wide range of solitary wave structures of different types. The dynamical profile is studied by using the bifurcation theory. This system is converted into a planar dynamical system via the Galilean transformation. Taking different cases of its coefficients, the phase plane analysis of this resultant dynamical system is performed. The phase diagrams show the different characteristics of the equilibrium points of the planar dynamical system. The quasi-periodic behaviors, multistability of this planar dynamical system are done by adding the perturbation term. The sensitivity assessment of this perturbed dynamical system is performed by taking different initial constraints.
Cosmology inflation in viscous mimetic f(R,T) gravity
Authors: Baffou E. H. , Houndjo M. J. S. , Salako I. G. , Gbètoho L. D.
Published: August 2023

We investigate in this work the inflationary scenario in viscous [Formula: see text] gravity formalism with mimetic potential and Lagrange multiplier. Considering that our universe contains beside a perfect fluid, a dark energy and a bulk viscous fluid, we obtain through the modified Friedmann equations a main differential equation that may describe the cosmological evolution in viscous mimetic [Formula: see text] gravity. For particular choice of the model [Formula: see text] and for two forms of bulk viscosity coefficient, one as function of the Hubbe parameter [Formula: see text] and the other, as density-dependent viscosity, we present a numerical results of the inflationary parameters such as the tensor-to-scalar ratio [Formula: see text] and the scalar spectral index [Formula: see text]. A comparison of these results with observational data shows that our model can be used to describe the accelerated expansion of the universe.
FLRW universe in f(Q,T) gravity
Authors: Shukla B. K. , Tiwari R. K. , Beesham A.
Published: August 2023

A cosmological model is described in this study using [Formula: see text] gravity, and the parameters are restricted using cosmological data sets. We start out by using a well-motivated form of [Formula: see text] as [Formula: see text], where [Formula: see text] and [Formula: see text] are model parameters. To solve the field equations, we use the relation that the deceleration parameter is inversely related to the Hubble parameter. In this case, we find that by parametrizing the cosmological parameters the transition redshift between early deceleration and late time acceleration occurs at [Formula: see text] The positive slope of the Om [Formula: see text] diagnostic analysis indicates that the model is in a phantom phase. Based on the current study, it seems that [Formula: see text] gravity might offer a substitute for dark energy in order to address the current cosmic acceleration.
Thin-shell wormholes with electromagnetic effects in f(R,T) gravity
Authors: Bhatti M. Z. , Yousaf Z. , Nazeer M.
Published: August 2023

The purpose of this paper is to study the feasibility and the appearance of charged thin-shell wormholes using generalized Chaplygin gas under the influence of minimally coupled [Formula: see text] gravitational theory. Here, [Formula: see text] is a generic function of the scalar curvature [Formula: see text] and the trace of stress-energy tensor [Formula: see text]. We explore different components of Lanczos equations in the context of a specific [Formula: see text] functional form, i.e. [Formula: see text], by applying junction conditions on field equations. We study static stable solutions using radial perturbation and the generalized Chaplygin gas equation of state (EoS) with the isotropic environment. We investigate the stable (unstable) static wormhole solutions for various physical parametric values and illustrate them graphically.