bluuebunny/crossref_metadata_2025_split huggingface dataset:
Webs, Nijenhuis operators, and heavenly PDEs
Authors: Panasyuk Andriy , Szereszewski Adam 
Published: September 2023

Abstract
In 1989 Mason and Newman (Commun. Math. Phys.
121 659–68) proved that there is a 1-1-correspondence between self-dual metrics satisfying Einstein vacuum equation (in complex case or in neutral signature) and pairs of commuting parameter depending vector fields

X
1

(
λ
)
,

X
2

(
λ
)

which are divergence free with respect to some volume form. Earlier Plebański (1975 J. Math. Phys.
16 2395–402) showed instances of such vector fields depending of one function of four variables satisfying the so-called I or II Plebański heavenly PDEs. Other PDEs leading to Mason–Newman vector fields are also known in the literature: Park (1992 Int. J. Mod. Phys. A 7 1415), Husain (1994 Phys. Rev. Lett.
72 800), Grant (1993 Phys. Rev. D 48 2606–12), Schief (Phys. Lett. A 223 55–62). In this paper we discuss these matters in the context of the web theory, i.e. theory of collections of foliations on a manifold, understood from the point of view of Nijenhuis operators. In particular we show how to apply this theory for constructing new ‘heavenly’ PDEs based on different normal forms of Nijenhuis operators in 4D, which are integrable similarly to their predecessors. Relation with the Hirota dispersionless systems of PDEs and the corresponding Veronese webs, which was recently observed by Konopelchenko–Schief–Szereszewski, is established in all the cases. We also discuss some higher dimensional generalizations of the ‘heavenly’ PDEs and the existence of related vacuum Einstein metrics in 4D-case.
First-principles studies on the structural, electronic, and optical properties of 2D transition metal dichalcogenide (TMDC) and Janus TMDCs heterobilayers
Authors: Habib Haris , Zhao Wenjing , Mir Sibgha , Ma Liang , Tian Guangjun 
Published: September 2023

Abstract
Van der Waals heterobilayers formed by vertically stacked two-dimensional materials could be a viable candidate for optoelectronics. This study carried out first-principles calculations to study the geometrical, electronic and optical properties of heterobilayers consisting transition metal dichalcogenide (TMDC) SnSe2 and Janus TMDCs ZrSSe and SnSSe. Eight possible configurations SeSnSe–SSnSe (I), SeSnSe–SeSnS (II), SeSnSe–SZrSe (III), SeSnSe–SeZrS (IV), SSnSe–SZrSe (V), SSnSe–SeZrS (VI), SeSnS–SZrSe (VII) and SeSnS–SeZrS (VIII) are dynamically, thermally, energetically and mechanical stable. Six configurations, (I, II, III, IV, V and VI) have indirect band gaps with type-II band alignments, enhancing carrier lifetime an essential feature for potential applications in photovoltaic and nanoelectronics devices. In contrast, VII and VIII have indirect band gap with a type-I band alignment, facilitating efficient recombination of electron–hole pairs under high irradiation. All heterobilayers demonstrated significant optical absorption in the visible region. These findings highlight the potential utilization of heterobilayers in electronic and optoelectronic devices.
A robust intelligent fault diagnosis method for rotating machinery under noisy labels
Authors: Chen Chengyuan , Wang Yi , Ruan Hulin , Qin Yi , Tang Baoping 
Published: September 2023

Abstract
Despite achieving considerable success, the fault diagnosis methods will still be disturbed by noisy labels, this causes the model’s degradation and reduced diagnostic precision. Focused on solving the above issues, a robust intelligent fault diagnosis approach for rotating machinery under noisy labels is proposed. Firstly, we maintain two deep neural networks (DNNs) and alternatively execute parameters updating and models optimization by referring to the Co-teaching strategy, which can maximize filtering different error types and implement pre-training of DNNs. Secondly, adopting a two-component Gaussian mixture model (GMM) to fit training dataset’s cross-entropy (CE) loss and realize the clean and noisy labels division according to the threshold. Then, a data augmentation method called Mixup operation is employed in semi-supervised learning (SSL) to increase noise robustness and avoid error accumulation, subsequently, performing fine-tuning and correction for clean and noisy samples. Challenging experiments on a transmission gearbox dataset under different noisy labels levels show that the proposed method has robustness to noise and significantly surpasses other approaches, which provides an important reference value for accurate fault diagnosis for rotating equipment parts with noisy labels.
The real-time vision measurement of multi geometric information of the rolled ring in the hot ring rolling process based on deep learning
Authors: Huang Kangwen , Wang Xiaokai , Dong Jie , Han Xinghui , Hua Lin 
Published: September 2023

Abstract
Hot ring rolling (HRR) is an advanced incremental metal-forming technology to manufacture high-performance rings. Nowadays, the mechanical or laser-sensors measurement methods can only obtain one value of the dimensions on the ring circumference per time unit, the measurement data is single and the information is limited. This paper presents a real-time vision measurement method for multi geometric information of the rolled ring such as ring’s diameter, center position, circularity and growth speed in HRR process. Firstly, the deep learning model is constructed to intelligently and quickly identify rolled ring targets from complex image backgrounds, then the adaptive linear gray scale transformation algorithm is proposed to adjust the gray scale contrast of the image according to changes in ring temperature, the interference of oxide scales and flying chips are eliminated by morphology operation. Finally, the least square method is used to fit the contour points, and further the rolled ring’s geometric information and corresponding variation trend are calculated. Several experiments are conducted on a vertical HRR mill, the geometric information of the rolled ring during the HRR is measured in real-time under the interference of harsh working conditions. For the ring with outer diameter of 350 mm, the measurement error of ring’s outer and inner diameter is less than 0.8 mm, the average processing time per image takes about 80 ms. The research provides a basis for accurate measurement of HRR process.
Advanced techniques in automated high-resolution scanning transmission electron microscopy
Authors: Pattison Alexander J , Pedroso Cassio C S , Cohen Bruce E , Ondry Justin C , Alivisatos A Paul , Theis Wolfgang , Ercius Peter 
Published: September 2023

Abstract
Scanning transmission electron microscopy is a common tool used to study the atomic structure of materials. It is an inherently multimodal tool allowing for the simultaneous acquisition of multiple information channels. Despite its versatility, however, experimental workflows currently rely heavily on experienced human operators and can only acquire data from small regions of a sample at a time. Here, we demonstrate a flexible pipeline-based system for high-throughput acquisition of atomic-resolution structural data using an all-piezo sample stage applied to large-scale imaging of nanoparticles and multimodal data acquisition. The system is available as part of the user program of the Molecular Foundry at Lawrence Berkeley National Laboratory.
Enhancing the mechanical properties of hydrogels with vinyl-functionalized nanocrystalline cellulose as a green crosslinker
Authors: Islam Hasanul Banna Muhammad Zukaul , Krishna Suresh Babu Naidu , Imran Abu Bin 
Published: September 2023

Abstract
Hydrogels have gained significant attention in scientific communities for their versatile applications, but several challenges need to be addressed to exploit their potential fully. Conventional hydrogels suffer from poor mechanical strength, limiting their use in many applications. Moreover, the crosslinking agents used to produce them are often toxic, carcinogenic, and not bio-friendly. This study presents a novel approach to overcome these limitations by using bio-friendly modified nanocrystalline cellulose as a crosslinker to prepare highly stretchable and tough thermosensitive hydrogels. The surface of nanocrystalline cellulose was modified with 3-methacryloxypropyltrimethoxysilane (MPTS) to obtain modified nanocrystalline cellulose (M-NCC) crosslinker and used during free radical polymerization of thermosensitive N-isopropyl acrylamide (NIPA) monomer to synthesize NIPA/M-NCC hydrogel. The resulting nanocomposite hydrogels exhibit superior mechanical, thermal, and temperature-responsive swelling properties compared to conventional hydrogels prepared with traditional bi-functional N, N′-methylene bis (acrylamide) (MBA) as a crosslinker. The elongation at break, tensile strength, and toughness of the NIPA/M-NCC hydrogels significantly increase and Young’s modulus decrease than conventional hydrogel. The designed M-NCC crosslinker could be utilized to improve the mechanical strength of any polymeric elastomer or hydrogel systems produced through chain polymerization.
Comparison of ultrasound elastography, magnetic resonance elastography and finite element model to quantify nonlinear shear modulus
Authors: Pagé Gwenaël , Bied Marion , Garteiser Philippe , Van Beers Bernard , Etaix Nicolas , Fraschini Christophe , Bel-Brunon Aline , Gennisson Jean-Luc 
Published: September 2023

Abstract

Objective. The aim of this study is to validate the estimation of the nonlinear shear modulus (

A

) from the acoustoelasticity theory with two experimental methods, ultrasound (US) elastography and magnetic resonance elastography (MRE), and a finite element method. Approach. Experiments were performed on agar (2%)—gelatin (8%) phantom considered as homogeneous, elastic and isotropic. Two specific setups were built to ensure a uniaxial stress step by step on the phantom, one for US and a nonmagnetic version for MRE. The stress was controlled identically in both imaging techniques, with a water tank placed on the top of the phantom and filled with increasing masses of water during the experiment. In US, the supersonic shear wave elastography was implemented on an ultrafast US device, driving a 6 MHz linear array to measure shear wave speed. In MRE, a gradient-echo sequence was used in which the three spatial directions of a 40 Hz continuous wave displacement generated with an external driver were encoded successively. Numerically, a finite element method was developed to simulate the propagation of the shear wave in a uniaxially stressed soft medium. Main results. Similar shear moduli were estimated at zero stress using experimental methods,

μ

0

U
S

= 12.3 ± 0.3 kPa and

μ

0

M
R
E

= 11.5 ± 0.7 kPa. Numerical simulations were set with a shear modulus of 12 kPa and the resulting nonlinear shear modulus was found to be −58.1 ± 0.7 kPa. A very good agreement between the finite element model and the experimental models (

A

U
S

= −58.9 ± 9.9 kPa and

A

M
R
E

= −52.8 ± 6.5 kPa) was obtained. Significance. These results show the validity of such nonlinear shear modulus measurement quantification in shear wave elastography. This work paves the way to develop nonlinear elastography technique to get a new biomarker for medical diagnosis.
Extracting the gradient component of the gamma index using the Lie derivative method
Authors: Anetai Yusuke , Doi Kentaro , Takegawa Hideki , Koike Yuhei , Nishio Teiji , Nakamura Mitsuhiro 
Published: September 2023

Abstract

Objective. The gamma index (γ) has been extensively investigated in the medical physics and applied in clinical practice. However, γ has a significant limitation when used to evaluate the dose-gradient region, leading to inconveniences, particularly in stereotactic radiotherapy (SRT). This study proposes a novel evaluation method combined with γ to extract clinically problematic dose-gradient regions caused by irradiation including certain errors. Approach. A flow-vector field in the dose distribution is obtained when the dose is considered a scalar potential. Using the Lie derivative from differential geometry, we defined L, S, and U to evaluate the intensity, vorticity, and flow amount of deviation between two dose distributions, respectively. These metrics multiplied by γ (γL, γS, γU), along with the threshold value σ, were verified in the ideal SRT case and in a clinical case of irradiation near the brainstem region using radiochromic films. Moreover, Moran’s gradient index (MGI), Bakai’s χ factor, and the structural similarity index (SSIM) were investigated for comparisons. Main results. A high L-metric value mainly extracted high-dose-gradient induced deviations, which was supported by high S and U metrics observed as a robust deviation and an influence of the dose-gradient, respectively. The S-metric also denotes the measured similarity between the compared dose distributions. In the γ distribution, γL sensitively detected the dose-gradient region in the film measurement, despite the presence of noise. The threshold σ successfully extracted the gradient-error region where γ > 1 analysis underestimated, and σ = 0.1 (plan) and σ = 0.001 (film measurement) were obtained according to the compared resolutions. However, the MGI, χ, and SSIM failed to detect the clinically interested region. Significance. Although further studies are required to clarify the error details, this study demonstrated that the Lie derivative method provided a novel perspective for the identifying gradient-induced error regions and enabled enhanced and clinically significant evaluations of γ.
Characterization of cardiovascular and cerebrovascular controls via spectral causality analysis in patients undergoing surgical aortic valve replacement during a three-month follow-up
Authors: Bari Vlasta , Gelpi Francesca , Cairo Beatrice , Anguissola Martina , Pugliese Sara , De Maria Beatrice , Bertoldo Enrico Giuseppe , Fiolo Valentina , Callus Edward , De Vincentiis Carlo , Volpe Marianna , Molfetta Raffaella , Ranucci Marco , Porta Alberto 
Published: September 2023

Abstract

Objective. Aortic valve stenosis (AVS) induces left ventricular function adaptations and surgical aortic valve replacement (SAVR) restores blood flow profile across aortic valve. Modifications of cardiac hemodynamics induced by AVS and SAVR might alter cardiovascular (CV) and cerebrovascular (CBV) controls. The study aims at characterizing CV and CBV regulations one day before SAVR (PRE), within one week after SAVR (POST), and after a three-month follow-up (POST3) in 73 AVS patients (age: 63.9 ± 12.9 yrs; 48 males, 25 females) from spontaneous fluctuations of heart period (HP), systolic arterial pressure, mean arterial pressure and mean cerebral blood velocity. Approach. CV and CBV regulations were typified via a bivariate autoregressive approach computing traditional frequency domain markers and causal squared coherence (CK
2) from CV and CBV variabilities. Univariate time and frequency domain indexes were calculated as well. Analyses were carried out in frequency bands typical of CV and CBV controls at supine rest and during active standing. A surrogate method was exploited to check uncoupling condition. Main results. We found that: (i) CV regulation is impaired in AVS patients; (ii) CV regulation worsens in POST; (iii) CV regulation recovers in POST3 and CV response to active standing is even better than in PRE; (iv) CBV regulation is preserved in AVS patients; (v) SAVR does not affect CBV control; (vi) parameters of the CBV control in POST3 and PRE are similar. Significance.
CK
2 is particularly useful to characterize CV and CBV controls in AVS patients and to monitor of patient’s evolution after SAVR.
High-speed imaging reveals the dynamics of the initiation and subsequent evolution of a nanosecond discharge propagating along the air–water interface
Authors: Hoffer Petr , Prukner Václav , Arora Garima , Šimek Milan 
Published: September 2023

Abstract
A nanosecond DBD-like discharge in a coplanar electrode configuration propagating along the water–air interface is an efficient source of reactive species to produce plasma-activated water. In this letter, we report on the mechanism of the discharge onset as well as on further developments over hundreds of nanoseconds. We combined ultrafast optical imaging with electrical characteristics to capture basic morphological imprints of individual discharge phases occurring during a single discharge event with high temporal resolution. We show that during the first nanoseconds, a diffuse bi-directional ionizing avalanche expands over the liquid surface at high speed (>5

×

105 m s−1). Later, discrete plasma filaments form from the diffuse plasma due to an ionization instability. The filaments, during their subsequent elongation (∼2

×

105 m s−1), retain the diffuse plasma at both ends. The filaments re-ignite in the same positions on the liquid surface over several successive (mainly capacitive) current pulses (∼1 μs apart), which result from discontinuities in the driving voltage.
Cylindrical helical cell metamaterial with large strain zero Poisson’s ratio for shape morphing analysis
Authors: Qin Qing , Dayyani Iman 
Published: September 2023

Abstract
In this paper, a novel cylindrical metamaterial with helical cell exhibiting zero Poisson’s ratio (ZPR) in two different directions is introduced. Detailed Computer-aided design modelling of a curved optimised spring element is demonstrated for numerical and experimental analysis. High fidelity finite element models are developed to assess the homogenisation study of Poisson’s ratios, normalised Young’s modulus and torsion behaviour, demonstrating the curvature effect and independency of mechanical behaviour of cylindrical optimised spring element metamaterial from tessellation numbers. Buckling and frequency analysis of the cylindrical metamaterial with spring element are compared with equivalent shell cylinders. Moreover, experimental analysis is performed to validate the large strain ZPR and deformation mechanism demonstrated in numerical simulations. Finally, radical shape morphing analysis under different bending conditions for cylindrical metamaterial with helical cell is investigated, including deformation and actuation energy and compared with positive and negative Poisson’s ratio cylinders formed by honeycomb and auxetic cells.
Modelling of the deformation behaviour of a magnetic hydrogel in a magnetic field gradient
Authors: Czichy C , Odenbach S 
Published: September 2023

Abstract
An ink made of alginate and methylcellulose with embedded magnetite microparticles was developed for extrusion printing. Constructs, so-called scaffolds, are colonised with cells which can be activated by mechanical stimulation. In this work, a defined magnetic field gradient is applied to achieve non-contact deformation. However, the deformation behaviour or relevant material parameters of the hybrid material are unknown. While the properties were determined with experiments adapted to hydrogels, a separate experimental set-up for micro-computed tomography, adapting the Maxwell configuration, was developed to investigate the deformation behaviour. These analyses were performed depending on ageing and particle concentration. For these tests, strands were used as bending beams, since these are simple and well known systems. Firstly, a model for the bending curve was erected, which defines a range in which the real bending curve would be expected. It was compared with the measured bending curves. There was very good agreement for the first days. On day 14, the measured bending curves were still within the calculated range, but at the lower limit due to the shortcomings of the model as the violation of the small deformations condition at this point. Secondly, the bending as a function of incubation duration was observed by a series of radiograms when a magnetic field gradient was applied. From this, a functional approach was formulated to describe the system response. Some parameters have already been identified, for others a proposal is given. Thirdly, microscopic analyses were carried out to observe the effects of the field gradient on particle distribution and structure. It was revealed that a homogeneous particle distribution was found even after 2.5 h. Also, in the direction of the field gradient, no chains were formed and no damage of the network could be detected. The obtained results show, that the material is suitable for mechanical stimulation.
Identification and reconstruction of anomalous data in dam monitoring considering temporal correlation
Authors: Chen Yongjiang , Wang Kui , Zhao Mingjie , Xiong Yong , Li Chuanzhou , Liu JianFeng 
Published: September 2023

Abstract
In dam monitoring, anomalous data is often removed directly by researchers. However, some anomalous data may be due to sudden changes in the state of the dam itself and should not be removed. In this study, anomalous data in dam monitoring is divided into two categories: anomalous error data caused by anomalies in the monitoring equipment, and anomalous warning data caused by sudden changes in the state of the dam itself. Then we propose a method for identifying and reconstructing anomalous data in dam monitoring that takes into account temporal correlation. This method is able to identify and retain anomalous warning data, while removing and reconstructing anomalous error data. To determine the temporal correlation between dam monitoring parameters (e.g. water level, horizontal displacement, etc), we use association rules, and to reconstruct the removed dam monitoring data in the case of an incomplete dataset, we propose a dam monitoring data reconstruction network (DMDRN) based on generative adversarial network. On this basis and in combination with the density-based spatial clustering of applications with noise algorithm, the types of anomalous data in dam monitoring are identified, and the anomalous error data is reconstructed based on DMDRN. Our approach has been successfully validated in two experiments to identify and reconstruct anomalous data at a particular dam in China.
Quantum resonant optical bistability with a narrow atomic transition: bistability phase diagram in the bad cavity regime
Authors: Rivero D , Pessoa Jr C A , de França G H , Teixeira R C , Slama S , Courteille Ph W 
Published: September 2023

Abstract
We report on the observation of a novel manifestation of saturation-induced optical bistability in a resonantly pumped optical ring cavity interacting strongly with a cloud of atoms via a narrow atomic transition. The bistability emerges, above a critical pump rate, as an additional peak in the cavity’s normal mode spectrum close to atomic resonance. This third transmission peak is usually suppressed due to strong resonant absorption, but in our experiment it is visible because of the linewidth of the atomic transition being much smaller than that of the cavity, which sets the experiment into the bad-cavity regime. Relying on complete saturation of the transition, this bistability has a quantum origin and cannot be mimicked by a classical material presenting a nonlinear refraction index. The appearance of the central peak in addition to the normal modes is predicted by a semi-classical model derived from the Tavis–Cummings Hamiltonian from which we derive a bistability phase diagram that connects our observations with former work on optical bistability in the good cavity regime. The phase diagram reveals several so far unexplored bistable phases.