bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elementary examples of renormalization from mechanics and integral calculus
Authors: Denny Mark 
Published: April 2024

Abstract
Two classical mechanical systems—block-and-tackle machines and nonlinear oscillators—exhibit renormalization of numerical parameters. A simple one-dimensional integral illustrates several other facets of renormalization (regularization, renormalization group, resummation). These examples provide insight for students and non-specialists into the workings of a subtle, complicated and historically misunderstood subject.
Local near-field scattering data enables unique reconstruction of rough electric potentials
Authors: Cañizares Manuel 
Published: April 2024

Abstract
The focus of this paper is the study of the inverse point-source scattering problem, specifically in relation to a certain class of electric potentials. Our research provides a novel uniqueness result for the inverse problem with local data, obtained from the near field pattern. Our work improves the work of Caro and Garcia, who investigated both the direct problem and the inverse problem with global near field data for critically singular and

δ

-shell potentials. The primary contribution of our research is the introduction of a Runge approximation result for the near field data on the scattering problem which, in combination with an interior regularity argument, enables us to establish a uniqueness result for the inverse problem with local data. Additionaly, we manage to consider a slightly wider class of potentials.
Advancements in bifunctional catalysts for unitized regenerative fuel cells: exploring polaronic conduction and heterostructure designs
Authors: Sharma Uma , Jha Pardeep K , Jha Priyanka A , Singh Prabhakar 
Published: April 2024

Abstract
This study investigates the development and performance evaluation of a bifunctional catalyst tailored for unitized regenerative fuel cells (URFCs), capable of facilitating both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in fuel cell and electrolyzer modes. The primary challenge addressed is the creation of electrocatalysts exhibiting high activity and corrosion resistance for oxygen reduction and water oxidation at the oxygen electrode. A novel catalyst structure based on La0.5Sr0.5Fe0.5Ti0.5O3(LSFT), i.e. LSFT/ZnO/LSFT with a thickness of

∼

2

μ

m, is explored within an environmentally friendly medium. This catalyst demonstrates superior performance characteristics, including reduced overpotential in HER and enhanced stability during oxygen/hydrogen evolution processes in neutral medium. This study identifies the formation of interfacial polarons and polaronic charge modulation resulting from the incorporation of ZnO in LSFT, leading to multifunctional OER/HER behavior. Notably, the proposed interfacial small polaron mechanism offers valuable insights into complex interfacial phenomena and holds promise for applications in diverse heterostructures involving layered 2D materials and transition metal oxides. Moreover, the robust LSFT/ZnO/LSFT catalyst exhibits exceptional stability, maintaining for 168 h of oxygen evolution at a constant potential of approximately 1.66 V for a current density of 1 A cm−2 in a neutral medium. These findings mark a significant advancement in URFC technology and present promising avenues for clean energy storage solutions.
Optimal speckle size and signal processing for displacement measurements using a 4f optical setup
Authors: Spaett A , Zagar B G 
Published: April 2024

Abstract
Fully developed laser speckle patterns are, due to their high contrast and statistical nature, well suited to measure strain and displacement via an appropriately designed measurement system. Laser speckle patterns are formed when a sufficiently coherent light source, such as a HeNe-laser, illuminates an optically rough surface. Therefore, methods based on laser speckle patterns can be applied to any surface scatterer with a minimum mean surface roughness of about a quarter of the laser’s wavelength. This includes also materials such as thin natural and technical fibres as well as foils, for which the presented measurement system, including the digital signal processing, was designed. In order to achieve the best possible resolution of a speckle-based measurement system, combined with a sufficiently small measurement uncertainty, all available design parameters must be optimised. One of these parameters is the speckle size, which is dependant on the properties of the imaging optics. In this paper a subjective laser speckle-based measurement system based on a so-called 4f-optical setup is presented. This setup allows the speckle size to be controlled in both axial and lateral dimensions separately, which is achieved with the help of an aperture in the Fourier plane of the optics. It is shown that the optimal speckle size for the presented measurement system, not only depends on the physical setup, but also on the signal processing applied. The signal processing routine estimates displacements of the speckle pattern, leading to an estimate for the strain. Additionally, it is demonstrated that the optimal speckle size can be lower than the commonly reported optimum between two and five pixel pitches, necessary to circumvent aliasing in the image data. While this is shown for a measurement setup using 4f-optics, the results are of general importance to speckle-based strain or displacement measurement systems and should thus be taken into account.
The RUL prediction based on improved Wiener degradation model for wet friction components
Authors: Wu Jianpeng , Li Pengpeng , Wang Liyong , Huang Xiaozan , Yang Jian , Du Molin 
Published: April 2024

Abstract
The wet clutch is a critical component of the comprehensive transmission system, and its reliability determines the stability of heavy equipment operation. As the core component of the wet clutch, the life of the wet friction components directly affects the reliability of the wet clutch. To accurately predict the wet friction components remaining useful life (RUL), an improved Wiener degradation model is established. Compared to traditional models, it sets drift parameters as random parameters to consider the randomness of degradation process. The life and degradation data of wet friction components are obtained through accelerated life test, and the composite degradation indicator is constructed by screening and fusing degradation data. Innovatively, we fuse life and degradation data to reduce early errors in RUL prediction of wet friction components. The result shows that the RUL prediction average absolute error of the improved Wiener degradation model is 0.31 h in the accelerated life range of 80 h–110 h, which verifies the accuracy of the model.
A hybrid approach to soft sensor development for distillation-in-series plant under input data low variability
Authors: Mozharovskii Igor , Shevlyagina Svetlana 
Published: April 2024

Abstract
This paper presents a hybrid approach for integrating fundamental process knowledge with measurement data to soft sensor (SS) development with improved estimation capability. Measurement data from sensors are collected and used as inputs for a first-principles model to emulate the data close to restrictions of the operating regulations, thus addressing a low variability problem of the inputs. Next, variables from measurement data and results of the first-principles modeling are combined to extend the training dataset for SSs, which become of a hybrid type in nature. To improve an estimation capability, a cascade-forward neural network and algorithm for alternating conditional expectation for nonparametric SS development was used. It was shown that the estimation capabilities of the developed SS can be improved by extending the training dataset with first-principles model data approximating the upper and lower limits of the process regime, the size of which in total does not exceed 21% of industrial data alone. As a result, the designed hybrid SS demonstrates a better efficacy in predicting quality index of the targeted distillation product with significantly reduced mean absolute error.
A dislocation density-based crystal plasticity constitutive model: comparison of VPSC effective medium predictions with ρ-CP finite element predictions
Authors: Patra Anirban , Tomé Carlos N 
Published: April 2024

Abstract
This work presents a dislocation density-based crystal plasticity constitutive model for glide kinetics, strengthening and dislocation density evolution, implemented in the effective medium-based visco-plastic self consistent (VPSC) framework and the spatially resolved, ρ-CP crystal plasticity finite element framework. Additionally, a distribution of intragranular stresses is introduced in the VPSC framework, instead of the conventionally used mean value of grain stress for effective medium calculations. The ρ-CP model is first calibrated to predict the mechanical response of a bcc ferritic steel with an initial rolled texture. The same set of constitutive model parameters are then used in VPSC to predict the aggregate stress–strain response and total dislocation densities. For these VPSC simulations, the interaction parameter governing the interaction between the grain and the effective medium in the Eshelby inclusion formalism, and a scalar parameter representative of the distribution of intragranular stresses within a grain, are used to calibrate the VPSC predictions in order to match the predictions of the ρ-CP model. A parametric study is performed to understand the effect of these two parameters on the VPSC predictions. Further, simulations are also performed for a random untextured polycrystal to identify the corresponding VPSC simulation parameters for predicting a similar response as the ρ-CP model. The novelty of the work is in the same set of constitutive models and associated parameters have been implemented in VPSC and ρ-CP to predict similar aggregate stress–strain response and total dislocation densities. This finite element-calibrated effective medium crystal plasticity approach reduces the computational time by at least two orders of magnitude and represents an advance towards the development of multiscale crystal plasticity modeling tools.
Exploring the evolution mechanisms of indentation and scratching on diamond structural transformation based on molecular dynamics
Authors: Tong Hua , Yang Yue , Liu Yunhai , Wang Xiaowen , Luo Yiyao , Zhang Hu , Mao Dongbi 
Published: April 2024

Abstract
Diamond, possessing high hardness and chemical stability, finds wide-ranging applications across various industries. However, during the friction process, a graphitization phenomenon may occur, which changes the mechanical properties of the diamond. In this study, molecular dynamics simulation was performed using SiC ball to investigate the influence of indentation depth and temperature on the graphitization transition of the diamond surface. The results showed that the dominant factor affecting the sp2 hybridization ratio during the indentation process was stress, while the temperature was the dominant factor during sliding. The results of this study can be used to understand the friction and wear behavior of diamonds and SiC ball and provide theoretical references for the industrial application of diamonds.
A mathematical analysis of the adiabatic Dyson equation from time-dependent density functional theory
Authors: Corso Thiago Carvalho 
Published: April 2024

Abstract
In this article, we analyse the Dyson equation for the density–density response function (DDRF) that plays a central role in linear response time-dependent density functional theory (LR-TDDFT). First, we present a functional analytic setting that allows for a unified treatment of the Dyson equation with general adiabatic approximations for discrete (finite and infinite) and continuum systems. In this setting, we derive a representation formula for the solution of the Dyson equation in terms of an operator version of the Casida matrix. While the Casida matrix is well-known in the physics literature, its general formulation as an (unbounded) operator in the N-body wavefunction space appears to be new. Moreover, we derive several consequences of the solution formula obtained here; in particular, we discuss the stability of the solution and characterise the maximal meromorphic extension of its Fourier transform. We then show that for adiabatic approximations satisfying a suitable compactness condition, the maximal domains of meromorphic continuation of the initial DDRF and the solution of the Dyson equation are the same. The results derived here apply to widely used adiabatic approximations such as (but not limited to) the random phase approximation and the adiabatic local density approximation. In particular, these results show that neither of these approximations can shift the ionisation threshold of the Kohn–Sham system.
Development of a smart artificial muscle using optical fibres
Authors: Tian Weihang , Wakimoto Shuichi , Yamaguchi Daisuke , Kanda Takefumi 
Published: April 2024

Abstract
A McKibben artificial muscle is a fluid-driven soft actuator comprising sleeve fibres and rubber tube. However, as typical bulky and rigid displacement sensors are unsuitable as sensor elements in soft actuators, displacement sensing is challenging for the McKibben artificial muscle. Therefore, we propose an optical fibre-based smart artificial muscle (OSAM) to estimate self-displacement from the bending loss of the optical fibre used as the sleeve fibre. The optical fibre can be effortlessly integrated into the OSAM sleeve using a braiding machine, which is generally used for manufacturing strings, easing the mass production process. The radius of curvature of the optical fibre changed when the OSAM was driven. The displacement of the artificial muscle was estimated based on the sensor output. To demonstrate the usefulness of OSAM, displacement feedback control experiments were conducted using the optical fibre sensor integrated into OSAM. From the results, OSAM’s displacement showed a good response to the target displacement. Therefore, the developed artificial muscle can facilitate displacement feedback control without requiring external sensors, which in turn can improve the performance of rehabilitation and wearable devices.
A locally resonant metamaterial beam with tunable electromagnetic stiffness based on the electromechanical analogy network
Authors: Deng Shiqi , He Yanyong , Wu Yudong , Ding Weiping 
Published: April 2024

Abstract
Locally resonant acoustic metamaterials offer distinctive advantages in controlling low-frequency elastic waves. However, passive structures often face limitations due to narrow bandgaps and fixed working band once they are fabricated. This paper introduces a novel metamaterial beam with tunable bandgaps. This achievement is made possible by employing one electromagnet and three permanent magnets to create an electromagnetic spring. The initial stiffness, provided by the spiral beam, collaborates with the electromagnetic components to establish a local resonant unite cell featuring tunable composite stiffness. Subsequently, an analogy network is formulated for the metamaterial beam based on electromechanical analogy theory. This network not only elucidates the generation mechanism and regulatory principles of bandgaps but also serves as a paradigm for the proactive design of the metamaterial beam with external control sources, particularly under finite period conditions. Finally, theoretical analysis and experimental results collectively demonstrate the flexibility of the proposed metamaterial beam in effectively suppressing low-frequency elastic waves across a wide frequency range.
Actuation strategy characterizations of a vibro-impact crawling robot driven by dielectric elastomer actuators
Authors: Cao Chongjing , Wu Chuang , Li Xiaozheng , Gao Xing 
Published: April 2024

Abstract
Vibro-impact crawling robots driven by the emerging dielectric elastomer actuators (DEAs) feature the advantages of reduced system complexity and bidirectional locomotion capability. However, due to the lack of systematic dynamic models and in-depth investigations, the fundamental locomotion principles of the robots are still unclear and therefore their applications in real-world scenarios remain hindered. In this paper, a comprehensive dynamic model of this robot is developed by considering the complex interactions between the electro-mechanical coupling, impact mechanism, and multiple nonlinear friction characteristics. By incorporating extensive modeling and experimental studies, we explain the fundamental principles that lead to the bidirectional locomotion of the robot. The actuation strategies for both forward and backward locomotion are characterized in-depth, which include the actuation frequencies, relative phases, and waveforms. Three typical contact surface cases (i.e. rigid & dry, rigid & viscous, compliant & viscous) are considered in this paper, where we report the changes in the optimal actuation strategies for bidirectional locomotion with the contact surfaces and reveal the influences of key factors of friction coefficient, viscosity, and material compliance. The key findings reported in this work can build foundations for developing a highly robust and efficient DEA-driven vibro-impact crawling robot for broad applications.
A semi-analytical simulation method for bi-directional functionally graded cantilever beams under arbitrary static loads
Authors: Zhang Long , Liao Wenlin , Fan Juntao , Feng Song 
Published: April 2024

Abstract
This paper presents a novel semi-analytical simulation approach for analysing the behaviour of bi-directional functionally graded cantilever beams subjected to arbitrary static loads, such as concentrated moments, concentrated forces, distributed force and their combinations applied at any location along the beam. The fundamental equations governing the cantilever beam’s response are derived, on the basis of which the proposed semi-analytical method is implemented using MATLAB programming language. The simulation results include field variables as well as stress contours, providing a compressive understanding of the beam’s behaviour. To validate the accuracy and reliability of the proposed method, a convergence study is conducted in comparison with the graded finite element method (GFEM) and analytical solutions. In the end, the developed method is applied to simulate the bending behaviour of bi-directional functionally graded cantilever beams under various loads individually and their combinations. The stress contours and deflection curves obtained from the simulation are compared with the solutions obtained using GFEM, revealing that the developed method possesses excellent capability in accurately simulating the bending behaviour of cantilever beams.
Low-energy avionic piezoelectric deicing system
Authors: Jomaa Modar , Lévy Pierre-Etienne , Vasic Dejan , Costa François , Ali Marwan 
Published: April 2024

Abstract
Piezoelectric actuators are widely used in several applications and are becoming increasingly attractive in aircraft and industrial contexts, mainly when efficiency and economical energy conversion are required. One of these applications is the avionic piezoelectric deicing system. Piezoelectric actuators are considered as a potential solution for developing a low-energy ice protection system for aircraft. This type of system applies vibration to the structure by activating its own resonant frequencies to generate sufficient stress to break the ice and cause it to delaminate from the substrate. The deicing mechanism depends strongly on the chosen excitation mode, whether it is flexural (bending) mode, extension (stretching) mode, or a combination in between, hence affecting the efficiency and effectiveness of the deicing process. In this contribution, a proof of concept of a deicing system utilizing lightweight piezoelectric actuators with minimal power requirement is proposed. Deicing was demonstrated with a power input density of 0.074 W cm−2 and a surface ratio of 0.07 piezoelectric actuators per cm2. First, a numerical method for positioning piezoelectric actuators and choosing the proper resonance mode was validated to assist in the system’s design. Then, the numerical method was used to implement piezoelectric deicing on a more representative structure of an aircraft wing or nacelle. Finally, a converter topology adapted for deicing application was proposed.
Consequence of anisotropy on flocking: the discretized Vicsek model
Authors: Karmakar Mintu , Chatterjee Swarnajit , Paul Raja , Rieger Heiko 
Published: April 2024

Abstract
We numerically study a discretized Vicsek model (DVM) with particles orienting in q possible orientations in two dimensions. The study investigates the significance of anisotropic orientation and microscopic interaction on macroscopic behavior. The DVM is an off-lattice flocking model like the active clock model (ACM; Chatterjee et al 2022 Europhys. Lett.
138 41001) but the dynamical rules of particle alignment and movement are inspired by the prototypical Vicsek model (VM). The DVM shows qualitatively similar properties as the ACM for intermediate noise strength where a transition from macrophase to microphase separation of the coexistence region is observed as q is increased. But for small q and noise strength, the liquid phase appearing in the ACM at low temperatures is replaced in the DVM by a configuration of multiple clusters with different polarizations, which does not exhibit any long-range order. We find that the dynamical rules have a profound influence on the overarching features of the flocking phase. We further identify the metastability of the ordered liquid phase subjected to a perturbation.
Measurement of infrared magic wavelength for an all-optical trapping of 40Ca+ ion clock
Authors: Huang Yao , Wang Miao , Chen Zheng , Li Chengbin , Zhang Huaqing , Zhang Baolin , Tang Liyan , Shi Tingyun , Guan Hua , Gao Ke-Lin 
Published: April 2024

Abstract
For the first time, we experimentally determine the infrared magic wavelength for the 40Ca+

4
s

2

S

1

/

2

→
3
d

2

D

5

/

2

electric quadrupole transition by observation of the light shift canceling in 40Ca+ optical clock. A ‘magic’ magnetic field direction is chosen to make the magic wavelength insensitive to both the linear polarization purity and the polarization direction of the laser. The determined magic wavelength for this transition is 1056.37(9) nm, which is not only in good agreement with theoretical predictions (‘Dirac–Fock plus core polarization’ method) but also more precise by a factor of about 300. Using this measured magic wavelength, we also derive the differential static polarizability to be −44.32(32) a.u., which will be an important input for the evaluation of the blackbody radiation shift at room temperatures. Our work paves a way for all-optical-trapping of 40Ca+ optical clock.