bluuebunny/crossref_metadata_2025_split huggingface dataset:
AI‐enabled bumpless transfer control strategy for legged robot with hybrid energy storage system
Authors: Huang Zhiwu , Yu Zi , Peng Hui , Wang Zixuan , Dai Xiaokang , Liu Weirong , Wang Jing 
Published: March 2024

AbstractDesigning Hybrid energy storage system (HESS) for a legged robot is significant to improve the motion performance and energy efficiency of the robot. However, switching between the driving mode and regenerative braking mode in the HESS may generate a torque bump, which has brought significant challenges to the stability of the robot locomotion. To address this issue, an AI‐enabled control strategy for bumpless transfer switching is proposed, which is composed of a Proximal Policy Optimisation (PPO)‐based non‐linear active disturbance rejection controller and Deep neural network (DNN)‐based bumpless transfer strategy. We indicate that the proposed intelligent strategy solves bumpless transfer by reducing the torque bump during the system switching process. Meanwhile, the authors analyse the energy driving subsystem and the energy regenerating subsystem based on operational modes and the energy flow. Via the parameters tuning criterion, the authors adopt a PPO algorithm to adaptively tune the parameters of the non‐linear active disturbance rejection controller, which can improve the performance of the primary torque control. A DNN‐based intelligent bumpless transfer strategy is proposed to set the initial value of two switching controllers at a switching moment. Simulations and experimental results validate the effectiveness of the proposed control strategy.
Wave propagation in finite discrete chains unravelled by virtual measurement of dispersion properties
Authors: Wang Zixin , He Guoqin , Wang Yichen , Fan Jiangwei , Zhang Yumeng , Chai Yisheng , Shang Dashan , Lu Sigma‐Jun 
Published: March 2024

AbstractTravelling waves in circuit chains are studied to measure continuous dispersion. A lock‐in frequency meter (LIF) is suitable for precisely determining k for each set of waves in finite alternate LC chains, where LIF has been proven to be more accurate than the fast Fourier transform. In addition to the –k measurement, the wave impedance spectrum of the travelling wave can be measured simultaneously, for investigating the dispersion and splitting of pulse propagation. The measured dispersion is validated to be consistent with the derived theoretical equations. The result provides an independent way to precisely obtain dynamical system properties for chains composed of non‐ideal components, such as resistors for researching non‐Hermitian behaviour under dissipation. Systematical mapping of relative deviation dependence of wave dispersion measurement with LIF on different chain length and component variation is studied, indicating boundaries of 1%, 0.1%, and 0.01% precision for guidance of experiments.
The advantage of Bolometric Interferometry for controlling Galactic foreground contamination in CMB primordial B-modes measurements
Authors: Manzan E. , Regnier M. , Hamilton J-Ch. , Mennella A. , Errard J. , Zapelli L. , Torchinsky S.A. , Paradiso S. , Battistelli E. , Bersanelli M. , De Bernardis P. , De Petris M. , D’Alessandro G. , Gervasi M. , Masi S. , Piat M. , Rasztocky E. , Romero G.E , Scoccola C.G. , Zannoni M. ,   the QUBIC Collaboration
Published: March 2024

In the quest for the faint primordial B-mode polarization of the Cosmic Microwave Background, three are the key requirements for any present or future experiment: an utmost sensitivity, excellent control over instrumental systematic effects and over Galactic foreground contamination.
Bolometric Interferometry (BI) is a novel technique that matches them all by combining the sensitivity of bolometric detectors, the control of instrumental systematics from interferometry and a software-based, tunable, in-band spectral resolution due to its ability to perform band-splitting during data analysis (spectral imaging).
In this paper, we investigate how the spectral imaging capability of BI can help in detecting residual contamination in case an over-simplified model of foreground emission is assumed in the analysis. To mimic this situation, we focus on the next generation of ground-based CMB experiment, CMB-S4, and compare its anticipated sensitivities, frequency and sky coverage with a hypothetical version of the same experiment based on BI, CMB-S4/BI, assuming that lineof-sight (LOS) frequency decorrelation is present in dust emission but is not accounted for during component separation.
We show results from a Monte-Carlo analysis based on a parametric component separation method (FGBuster), highlighting how BI has the potential to diagnose the presence of foreground residuals in estimates of the tensor-to-scalar ratio r in the case of unaccounted Galactic dust LOS frequency decorrelation.
Supplementary comparisons of DC high voltage measuring reference instruments COOMET 449Ru-a08 (COOMET_EM-S7)
Authors: Kiselev Victor , Gromochkova Elena , Dubrovskaya Tatiana , Garnacho Fernando , Kumanova Ginka , Kikalo Valery , Kopshin Vladimir 
Published: March 2024

Main text
To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.
The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Corrigendum: Dynamic micromechanical measurement of the flexural modulus of micrometre-sized diameter single natural fibres using a vibrating microcantilever technique (2024 J. Micromech. Microeng.
34 015009)
Authors: Reda Ali , Dargent Thomas , Arscott Steve 
Published: March 2024

Abstract
This corrigendum corrects typographic errors in the article. The corrections do not change the conclusions of the article.
Laser-assisted (e,2e) study with twisted electron beam on H-atom
Authors: Neha  , Dhankhar Nikita , Pinto Raul Sheldon , Choubisa Rakesh 
Published: March 2024

Abstract
We study the laser-assisted twisted electron beam impact ionization of the hydrogen atom in coplanar asymmetric geometry. We develop the theoretical model in the first Born approximation. In the presence of the laser field, we treat the incident and scattered electrons as Volkov waves; the ejected electron, moving in the combined field of the laser and residual ion

H
+

, as a Coulomb–Volkov wave function. In this communication, we compare the angular profile of triple differential cross-section (TDCS) for laser-assisted twisted electron beam incidence with the plane-wave, laser-assisted plane wave, and field-free twisted electron beam for (e,2e) processes for different orbital angular momentum (OAM) number (ml
) values. We analyze the effect of impact-parameter b of twisted electron beam and the laser parameters on the angular distribution of the TDCS. We study the

(
T
D
C
S

)

av

for the macroscopic target to examine the effect of opening angle θ

p
of the twisted electron beam on the angular profile of TDCS. We also observe the influence of coherent superposition of two Bessel states on the angular profile of TDCS. Our results clearly show the effects of laser parameters (electric field ɛ and number of photon exchanged (l)) and twisted electron beam parameters (OAM number (ml
) and opening angle (θ

p
)) on the angular distribution of TDCS.
Analysis of electron induced single ionisation differential cross-section of CO2 molecules in different kinematics
Authors: Pandey Alpana , Purohit Ghanshyam 
Published: March 2024

Abstract
Theoretical investigations of electron-impact ionisation for carbon dioxide (CO2) in low to intermediate energy ranges are presented. In addition to the energy range, we have estimated triple differential cross-section (TDCS) in coplanar and perpendicular plane geometry. We have calculated the TDCS for electron impact using the modified distorted wave formalism up to the second order. Post-collision interaction effects have also been introduced to describe the collision dynamics accurately. There is a good correlation between the distorted-wave Born approximation results and the experimental results in terms of forward and backward scattering regions.
Modeling and assessment of Galileo PPP one-way timing with RT-product
Authors: Wang Guofang , Xu Lei , Jiang Chenhui , Yu Ye , Mu Di , Wen Gang , Wang Yifan 
Published: March 2024

AbstractPrecise point positioning (PPP) technology is widely used in positioning, navigation, and timing. In order to meet the needs of users for real-time high-precision time information, a real-time Galileo PPP one-way timing model based on existing real-time (RT) products (CAS, CNES, GMV, and WHU) was established and applied for the timing field. Experiments were designed with 8 GNSS stations with an external H-MASER clock to research Galileo PPP timing with 25 day observations. For the modified Allan deviation (MDEV) of Galileo PPP timing solutions, similar to the timing solutions of GPS, the MDEV of Galileo PPP with CAS and CNES shows worse short-term frequency stability, with 1 to 2 × 10−13at 960 s stability, and indicates similar long-term frequency stability, with about 5–6 × 10−15at 61 440 s stability. For Galileo PPP time transfer, the standard deviation values are about 0.01–0.49 ns for all time-links with different products. For the stability of Galileo time transfer, the similar characteristic of Galileo time transfer is comparable to that of GPS. For short-term stability, the MDEV of all time-links from Galileo PPP ranges from 2 × 10−14to 3 × 10−14at 960 s. For long-term stability, 1 to 2 × 10−15levels can be reached at 61 440 s for all time-links, except for that of CNES.
Construction health indicator using physically-informed 1D-WGAN-GP joint attention LSTM-DenseNet method
Authors: Yang Hai , Yang Xudong , Sun Dong , Hu Yunjin 
Published: March 2024

Abstract
In data-driven prognosis methods, the accuracy of predicting the remaining useful life (RUL) of mechanical systems is predominantly contingent upon the efficacy of system health indicators (HI), typically amalgamated from statistical features derived from collected signals. Nevertheless, the majority of extant HI are beset by two principal shortcomings: (1) during traditional data denoising processes, degradation information from raw data is prone to loss owing to the lack of incorporation of the true physical properties of the data; and (2) the performance evaluation of constructed HI is imbalanced due to the influence of network structures on single models, often resulting in strong performance in only one or two indicators. To overcome such shortcomings, a mechanical health indicator construction method based on physical properties was proposed, termed 1D-WGAN-GP Joint attention LSTM-DenseNet. Firstly, artificial sample data is generated by analyzing the physical properties of the original dataset, which is then used to train the 1D-WGAN-GP model to achieve data denoising. Subsequently, the fusion of the attention LSTM (A-LSTM) network and DenseNet network is utilized to extract crucial feature vectors of HI under varying health conditions from the denoised data. Finally, the extracted feature vectors are used to construct system HI using the Euclidean distance method, and these indicators are used for predicting the system’s RUL. The results indicate that the proposed method outperformed traditional methods in terms of denoising effectiveness. Further, through ablation experiment analysis, the HI constructed by the proposed method demonstrated obvious complementarity in terms of monotonicity, correlation, robustness, and comprehensive evaluation. In RUL prediction applications, the proposed method also exhibited good performance, thereby validating its effectiveness.
Phase-field modeling of stored-energy-driven grain growth with intra-granular variation in dislocation density
Authors: Huang Guanglong , Mensah Alexander , Chlupsa Marcel , Croft Zachary , Qi Liang , Shahani Ashwin J , Thornton Katsuyo 
Published: March 2024

Abstract
We present a phase-field (PF) model to simulate the microstructure evolution occurring in polycrystalline materials with a variation in the intra-granular dislocation density. The model accounts for two mechanisms that lead to the grain boundary migration: the driving force due to capillarity and that due to the stored energy arising from a spatially varying dislocation density. In addition to the order parameters that distinguish regions occupied by different grains, we introduce dislocation density fields that describe spatial variation of the dislocation density. We assume that the dislocation density decays as a function of the distance the grain boundary has migrated. To demonstrate and parameterize the model, we simulate microstructure evolution in two dimensions, for which the initial microstructure is based on real-time experimental data. Additionally, we applied the model to study the effect of a cyclic heat treatment (CHT) on the microstructure evolution. Specifically, we simulated stored-energy-driven grain growth during three thermal cycles, as well as grain growth without stored energy that serves as a baseline for comparison. We showed that the microstructure evolution proceeded much faster when the stored energy was considered. A non-self-similar evolution was observed in this case, while a nearly self-similar evolution was found when the microstructure evolution is driven solely by capillarity. These results suggest a possible mechanism for the initiation of abnormal grain growth during CHT. Finally, we demonstrate an integrated experimental-computational workflow that utilizes the experimental measurements to inform the PF model and its parameterization, which provides a foundation for the development of future simulation tools capable of quantitative prediction of microstructure evolution during non-isothermal heat treatment.
Modelling of vertical displacement events in tokamaks: status and challenges ahead
Authors: Artola F J , Schwarz N , Gerasimov S , Loarte A , Hoelzl M ,   the JOREK Team
Published: March 2024

Abstract
In this paper, we revisit the physics of mitigated and unmitigated vertical displacement events (VDEs) and present a summary of present modelling efforts and code capabilities. While 3D MHD simulations of VDEs for AUG and JET are now approaching realistic plasma parameters (e.g. resistivity) and getting closer to experimental observations (e.g. CQ times and vessel forces), the time scales of ITER VDEs (∼500 ms) are still out of computational reach. Therefore, re-scaling of plasma parameters, model simplifications or demanding matrix pre-conditioning techniques are required. We describe such techniques and compare AUG, JET and ITER unmitigated VDE simulations in terms of the dynamics of the CQ and total vacuum vessel forces. In JET simulations, the safety factor (q
95) falls to unity during the current quench, which destabilizes a 1/1 kink mode. On the other hand, in AUG and ITER simulations, MHD activity is more effective preventing the drop of q
95, leading to comparatively smaller forces in these devices. We will also discuss the applicability of axisymmetric plasma simulations and their success on simulating mitigated disruptions. Finally we review the remaining modelling challenges and future plans for unmitigated disruptions. For example, MHD codes need to improve their scrape-off-layer modelling, such as including the limitation of the halo current to the ion saturation current. Although crucial, this remains numerically challenging even for axisymmetric simulations.
Study of quantum Szilard engine for non-interacting bosons in fractional power-law potentials
Authors: Islam Najirul 
Published: March 2024

Abstract
In this article, we have realized the quantum Szilard engine (QZE) for non-interacting bosons. We have adopted the Bose–Einstein statistics for this purpose. We have considered fractional power law potential for this purpose and have used the artifact of the quantization of energy. We have calculated the work and the efficiency for non-interacting bosons in fractional power potential. We have shown the dependence of the number of particles for the work and the efficiency. We also have realized the QZE for a single-particle in a Morse potential revealing how the depth of the potential impacts both work and efficiency. Furthermore, we have examined the influence of temperature and the anharmonicity parameter on the work. Finally, we have conducted a comparative analysis, considering both non-interacting bosons in a fractional power law potential and a single-particle in a Morse potential under harmonic approximation conditions.
Simultaneously enhanced of energy storage and energy harvesting performances of [(Bi0.5Na0.5)TiO3–BaTiO3] ceramics by addition of SrTiO3
Authors: Kamal Amira A , Hussein S A , Salem A , Mahmoud Abd El-razek 
Published: March 2024

Abstract
As is well known, relaxor dielectrics are characterized by high energy storage efficiency (η), while high recoverable energy storage density (Wrec) can be achieved by anti-ferroelectric ceramics. Herein, our approach is to find relaxor- anti-ferroelectric coexistence phases of (Bi0.5Na0.5)TiO3- BaTiO3 ceramics for achieving high performance in energy storage and energy harvesting as well. Therefore, [(0.9-x) ( Bi0.5Na0.5)TiO3-xSrTiO3-0.1BaTiO3] (abbreviation (0.9-x) NBT-0.1BT-xST) (0.0 ≤ x ≤ 0.4) were synthesized via the solid-state reaction route in air. The tolerance factor (τ) increased from 0.9901 to 0.9998 when ST-content increased from 0.0 to 0.4, indicating an increase in crystal lattice symmetry. The FT-IR de-convolution vibration modes shown in the TiO6 octahedra exhibit two peaks at ∼550 and 650 cm−1, which indicate present coexistence phases of the crystal structure. Ferroelectric to relaxor phase crossover has been detected by the addition of ST with the present anti-ferroelectric phase in particular dopant ST = 0.2. The increasing into the diffused phase transition (γ) is signified by enhancement of the relaxor degree of NBT-BT at high content of ST. The rapidly suppressed remnant polarization (Pr) at high content of ST is due to substitute iso-valence (Sr2+) by tri-valence (Bi3+) and mono-valence (Na1+). Ultrahigh

W

rec

= 1.13 J/

cm

3

with excellent η = 92.62% were obtained at ST = 0.3 at low electric field (E = 110 kV cm−1). A remarkable response of the strain with a high converse piezoelectric coefficient (

d

33

*

= 390.47 pm V−1) at ST = 0.2 was obtained due to decreasing the non-revisable 180° domain switching. Based on the obtained results, the addition of ST to NBT-BT ceramics can provide a head start in the implementation of ceramic capacitors for potential effective into energy harvesting and energy storage applications.
First-principle investigation of lead-free double perovskites Cs2MScCl6 (M = Na, K) for optoelectronic and thermoelectric applications
Authors: Afridi Al Mojahid , Nipa Nasrin Afroz , Abdur Rashid Mohammad 
Published: March 2024

Abstract
Double perovskite optoelectronic devices are gaining popularity due to their advantageous features, such as an efficient and easy-to-manage crystalline structure. In this study, we looked into the optoelectronic, mechanical, and thermoelectric attributes of Cs2MScCl6 (with M being Na or K) using density functional theory. The obtained results show that both compounds can exist stably in cubic double perovskite structure, space group

Fm

3

¯

m

. The electronic band structures of Cs2NaScCl6 and Cs2KScCl6 demonstrate a direct semiconducting band gap of 3.829 eV and 3.996 eV, respectively. As the pressure rises up to 200 GPa, Cs2KScCl6 reveals extraordinary tunability along with an indirect band gap of 2.000 eV. Moreover, optical analysis—comprising dielectric constant calculations, absorption coefficient measurements, refractive indices checks, reflectivity assessments, energy loss estimations, and electrical conductivity appraisals—shows promising results too. Specifically, the absorption coefficient and conductivity predominantly fall within the ultraviolet range under normal atmospheric pressure. The thermoelectric characteristics suggest a noteworthy Seebeck coefficient, low thermal conductance and good figure of merit implying it could be used in the domain of sustainable energy.
Primordial non-Gaussianities with weak lensing: information on non-linear scales in the Ulagam full-sky simulations
Authors: Anbajagane Dhayaa , Chang Chihway , Lee Hayden , Gatti Marco 
Published: March 2024

Abstract
Primordial non-Gaussianities (PNGs) are signatures in the density field that encode particle physics processes from the inflationary epoch. Such signatures have been extensively studied using the Cosmic Microwave Background, through constraining their amplitudes, fX

NL, with future improvements expected from large-scale structure surveys; specifically, the galaxy correlation functions. We show that weak lensing fields can be used to achieve competitive and complementary constraints. This is shown via the Ulagam suite of N-body simulations, a subset of which evolves primordial fields with four types of PNGs. We create full-sky lensing maps and estimate the Fisher information from three summary statistics measured on the maps: the moments, the cumulative distribution function, and the 3-point correlation function. We find that the year 10 sample from the Rubin Observatory Legacy Survey of Space and Time (LSST) can constrain PNGs to σ(f
NL
eq) ≈ 110, σ(f
NL
or, lss) ≈ 120, σ(f
NL
loc) ≈ 40. For the former two, this is better than or comparable to expected galaxy clustering-based constraints from the Dark Energy Spectroscopic Instrument (DESI). The PNG information in lensing fields is on non-linear scales and at low redshifts (z ≲ 1.25), with a clear origin in the evolution history of massive halos. The constraining power degrades by ∼60% under scale cuts of ≳ 20 Mpc, showing there is still significant information on scales mostly insensitive to small-scale systematic effects (e.g., baryons). We publicly release the Ulagam suite to enable more survey-focused analyses.
Cosmological teleparallel perturbations
Authors: Heisenberg Lavinia , Hohmann Manuel , Kuhn Simon 
Published: March 2024

Abstract
There has been growing interest in f(ℚ) gravity, which has led to significant advancements in the field. However, it is important to note that most studies in this area were based on the coincident gauge, thus overlooking the impact of the connection degrees of freedom. In this work, we pay special attention to the connection when studying perturbations in general teleparallel, metric teleparallel, and symmetric teleparallel theories of gravity. We do not just examine perturbations in the metric, but also in the affine connection. To illustrate this, we investigate cosmological perturbations in f(G), f(𝕋), and f(ℚ) gravity with and without matter in form of an additional scalar field for spatially flat and curved FLRW geometries. Our perturbative analysis reveals that for general f(ℚ) backgrounds, there are up to seven degrees of freedom, depending on the background connection. This is in perfect agreement with the upper bound on degrees of freedom established for the first time in https://doi.org/10.1002/prop.202300185
Fortschr. Phys.
71 (2023) 2300185.
In f(G) and f(𝕋) gravity theories, only two tensor modes propagate in the gravity sector on generic curved cosmological backgrounds, indicating strong coupling problems.
In the context of f(ℚ) cosmology, we find that for a particular background connection, where all seven modes propagate, there is at least one ghost degree of freedom.
For all other choices of the connection the ghost can be avoided at the cost of strong coupling problem, where only four degrees of freedom propagate. Hence, all of the cosmologies within the teleparallel families of theories in form of f(G), f(ℚ), and f(𝕋) suffer either from strong coupling or from ghost instabilities. A direct coupling of the matter field to the connection or non-minimal couplings might alter these results.