bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental study on laser cutting process of titanium–zirconium amorphous alloy
Authors: Yao YanSheng , Xu XinPeng , Zhang Chenglin , Ma Xiaoqiang 
Published: January 2024

This paper aims to assess the effects of various laser cutting parameters on the surface roughness of 2 mm thick titanium–zirconium amorphous alloy sheets. With multiple linear regression, a mathematical model was proposed to predict the maximum height of surface Sz as a function of two laser cutting parameters: cutting speed and assist gas pressure. The adequacy of the proposed model was evaluated using the analysis of variance method. Scanning electron microscopy was then used to observe the surface topography of the material following laser cutting under different conditions. It was found that for a fixed laser power, cutting speed dominates the parameter that determines the maximum height of surface roughness.
Enhancement of coercivity in polybenzoxazine/CoxMg1−xFe2O4 nanoferrite composites: Synthesis and characterization
Authors: Ghosh Ashesh , Zaheen Muntaka , Islam Ariful , Rahman Md. Sohanur , Sharif Ahmed , Hoque Sheikh Manjura 
Published: January 2024

In this research, we synthesize composites of CoxMg1−xFe2O4 (0 ≤ x ≤ 1) spinel nano-ferrites and polybenzoxazine (PBZ) and characterize their structural, optical, and magnetic properties. The magnetic nanoparticles are fabricated using the chemical co-precipitation method. The benzoxazine (BZ) monomer is synthesized by Mannich condensation reaction using aniline, paraformaldehyde, and phenol. Specific weights of the ferrite particles and BZ monomer are then mixed and thermally treated to produce the composites. X-ray diffraction (XRD) ensures that the desired spinel phase is formed. Moreover, the average crystallite size calculated from the XRD data ranges from 5.3 to 15.5 nm, which shows a fair degree of agreement with the transmission electron microscope images. Energy dispersive x-ray spectroscopy has confirmed the chemical composition of the samples. Fourier transform infrared characterization has been used to confirm the formation of BZ and PBZ. The magnetic properties at room temperature are evaluated using a vibrating sample magnetometer. Increasing the cobalt content has increased the saturation magnetization (Ms) significantly in the ferrite samples while creating composites with PBZ decreased the Ms values. We find that the coercivity (Hc) of the composites has increased more than that of the bare ferrite particles. The optical properties are evaluated by ultraviolet–visible spectrophotometry (UV–Vis) analysis, where it is found that the optical bandgap increases with an increase in the Mg component. Higher retention of the magnetic properties in the composite, especially coercivity (Hc), shows potential for applications that require high magnetic properties in combination with structural flexibility.
Fluorescence in the estimation of chlorophyll-a in public water reservoirs in the Brazilian cerrado
Authors: Souza de Barros Lucélia , de Almeida Tati , Moraes Soares Raquel , Dias Batista Bruno , Dantas Borges Henrique , Ennes Cicerelli Rejane 
Published: January 2024

Context The usual strategy for monitoring of eutrophication process is the use of traditional limnological methods, based on laboratory analysis. These procedures involve costly and time-consuming analyses, usually with in vitro methodologies, which can still have limitations in terms of sensitivity and reliability, if poorly managed. Phytoplankton pigments, such as chlorophyll-a (Chl-a), are highly fluorescent and can provide the environmental status of water bodies. Aims This study aims to analyse, compare and evaluate an estimation of Chl-a through fluorescence in public water sources in the Brazilian cerrado. Exploratory statistical analyses were conducted by using absolute fluorescence units (AFU) and relative fluorescence units (RFU) compared with traditional laboratory data (standard procedure for the determination of Chl-a by spectroscopic methods) to evaluate the significance of differences in estimating Chl-a concentration. Subsequently, empirical models, based on spectral band combinations, were generated to convert fluorescence measurement in Chl-a concentration, by linear regression. Key results The generated model found a strong correlation and coefficient of determination (r = 0.88; R2 = 0.78). The efficiency of the model was also confirmed by statistical indicators (RMSE = 1.27, MAPE = 26.72 and BIAS = −6.32). Conclusions We concluded that the estimate of Chl-a through RFU was better than through AFU. Implications Therefore, based on the results of this study, it is recommended that RFU be used to obtain more precise and accurate estimates of Chl-a concentration through empirical models based on linear regression.
Implication of nano-Hertz stochastic gravitational wave on dynamical dark matter through a dark first-order phase transition
Authors: Jiang Siyu , Yang Aidi , Ma Jiucheng , Huang Fa Peng 
Published: January 2024

Abstract
For the first time, the expected stochastic gravitational wave background is probably discovered after observing the Hellings Downs correlation curve by several pulsar timing array (PTA) collaborations around the globe including NANOGrav, European PTA, Parkes PTA, and Chinese PTA. These new observations can help to explore or constrain the dark matter (DM) formation mechanisms in the early Universe. We study the implication of those results on the dynamical DM formation mechanisms through a dark first-order phase transition in the early Universe. Both the Q-ball DM and super-cool DM are investigated in the strong super-cooling dark phase transition scenario which may give an interpretation of the observed stochastic gravitational wave background.
Study on fracture characteristics and mechanisms of red sandstone under high-voltage pulse discharge
Authors: Hao Qiqi , Zhang Fengpeng , Peng Jianyu , Yan Guangliang , Du Chuan 
Published: January 2024

Abstract
To investigate the influences of geometrical size and discharge voltage of the pulse discharge equipment on the fracture characteristics and mechanisms of sandstone under high-voltage pulses, a series of experiments was conducted using a high-voltage pulse discharge device on sandstone circular disc specimens of sandstone with a thickness of 10 mm. These experiments covered a range of disc diameters ranging from 50 mm to 142 mm and discharge voltages from 15 kV to 40 kV. Through these experiments, the fracture characteristics of sandstone at both macroscopic and microscopic levels were investigated. In the experiments, a quantitative analysis of surface fracture was undertaken based on fracture density and fractal damage. Additionally, using the principle of energy equivalence, numerical simulation methods were used to study the damage evolution process in sandstone. The research results indicate that the formation and distribution of fractures in the sandstone specimens are significantly affected by geometrical size and discharge voltage. By analyzing the interaction between stress waves and fracture propagation, combined with indoor experimental results, the fracture mechanism was revealed. The high temperature and shock wave generated by the plasma channel leads to the crushing zone near the electrode, while the circumferential tensile component of the stress wave can result in radial fractures, and the reflected tensile wave leads to circumferential and radial fractures near the boundary.
Re-emerging magnetic order in correlated van der Waals antiferromagnet NiPS3
Authors: Zhou Xueli , Xu Haihong , Zhang Jiang , Tang Lingyun , Chen Xi , Mao Zhongquan 
Published: January 2024

Abstract
Van der Waals (vdW) gap is a significant feature that distinguishes vdW magnets from traditional magnets. Manipulating the magnetic properties by changing the vdW gap has been hot topic in condensed matter research. Here we report a re-emerging magnetic order induced by pressure in a correlated vdW antiferromagnetic insulator NiPS3. It is found that the interlayer magnetoresistance (MR) nearly vanishes at the critical pressure where the crystal structure transforms from C2/m phase to the sliding C2/m phase. On further compression within the sliding C2/m phase, a substantially enhanced MR emerges from low temperature associated with an insulator-to-metal transition, indicating a metallic antiferromagnetic phase. The enhanced re-emerging MR in sliding C2/m phase can be ascribed to the increasing magnetic interaction between neighboring layers due to the vdW gap narrowing. Our results provide important experimental clues for understanding the pressure effects on magnetism in correlated layered materials.
Fault prediction of unmanned aerial vehicles based on entropy weight fusion and temporal graph convolutional network with non-Euclidian structure
Authors: Zhang Shaohui , Yao Yongjie , Jiang Fei , Mo Jinhua , Wu Zhaoqian , Liang Jinglun 
Published: January 2024

Abstract
Predicting weak and hidden faults in unmanned aerial vehicles (UAVs) is challenging due to their variable operation conditions and complex mechanisms. Conventional neural network models process the multisensory data in the form of Euclidean structure, the intrinsic connections among the individual data points are easy to be disregarded. Additionally, multisensory data are always directly fed into the model without adequately considering the importance or contribution of each sensor. Hence, an UAV fault prediction method is proposed by combining entropy weight fusion with a temporal graph convolutional network (GCN) to address the above problems. Firstly, the importance of multisensory data of UAVs are evaluated by each entropy value, and the multisensory data fusion is further realized by multiplying corresponding signal and entropy weight. Secondly, the multisensory data combined with fusion data are transferred together into graph-structure by adjacent matrix based on the node connection between different sensor data. Finally, the graph-structure data with non-Euclidian distance properties are input into temporal GCN to both capture the spatial and temporal relationship of the data, achieving better fault prediction results of UAVs. It is demonstrated that the proposed method is both applicable and superior in characterizing and predicting fault time series information of UAVs through parameter analysis and comparison studies with various existing algorithms.
Preparation of a high-performance H2S gas sensor based on CuO/Co3O4 composite derived from bimetallic MOF
Authors: Li Zhanhong , Wang Xu , Yao Yu , Xin Jiangang , Xie Lili , Han Yutong , Zhu Zhigang 
Published: January 2024

Abstract
The bimetallic metal–organic frameworks (MOFs), Cu/Co-MOF, was synthesized through a solvothermal method and calcined to obtain CuO/Co3O4 composites. By adjusting the molar ratio between Cu and Co ions, a composite material of CuO/Co3O4 (Cu:Co = 1:1) was developed and showed excellent sensing capabilities, and the response reached as high as 196.3 for 10 ppm H2S detection. Furthermore, the optimal operating temperature as low as 40 °C was found. In comparison with the sensors prepared by pristine CuO and pristine Co3O4, the sensor based on CuO/Co3O4 composite exhibited a significant response. Additionally, the sensor can detect H2S gas down to 300 ppb. The gas sensing mechanism is discussed in depth from the perspective of p–p heterojunction formation between the p-type CuO and p-type Co3O4. The as-prepared CuO/Co3O4 composite-based sensor is expected to find practical application in the low-power monitoring of H2S.
Plasma kinetic simulation in Eulerian approach fully respecting f≥0 requirement and total particle number conservation
Authors: Lin H , Liu C P 
Published: January 2024

Abstract
Plasma kinetic simulation in Eulerian approach (PKSiEA) can yield a dynamic description on plasmas and hence is a popular method in theoretical plasmas physics. Its mathematical model consists of 8 members: 5 partial differential equations (PDEs), a phase space boundary condition and an initial condition of the distribution function (PDF) f, and a mandatory non-negativity requirement on f. Because Vlasov equation (VE) is a PDE with variable coefficients and the non-negativity requirement is mandatory, when 5 PDEs (4 Maxwell equations and the VE) are treated as an initial-value problem, the temporal evolution of f is difficult to be attacked by existing popular computational mathematics techniques, such as Fourier analysis technique and finite-difference technique, and hence these techniques do not yield efficient and reliable schemes of the PKSiEA. In a universal scheme of the PKSiEA presented here, because the phase space boundary condition f∣
r=∞,∣υ∣=c
= 0 causes the VE to yield a conservation of total particle number ∫fd
3
rd
3
υ, we propose an efficient and strict expression of the f-profile in terms of two classes of functions of phase space coordinates

r
,
υ

, and the VE displays a universal relation between two classes. By this new expression, we express the initial-value problem of 5 PDEs in terms of allowed deformation modes from an initial f-profile, and ensure the PKSiEA fully respecting the non-negativity requirement on f.
Degradable and biocompatible nanofibrous scaffold incorporating a natural cell culture medium for skin tissue engineering
Authors: Afrashi Mehran , Semnani Dariush , Hashemibeni Batool , Shokrgozar Mohammad Ali 
Published: January 2024

Abstract
The use of green materials in biomedical and bioengineering applications has significantly expanded in recent years. In this study, we utilized egg white (EW) as an abundant and cost-effective green material, blended with polycaprolactone/gelatin (PCL/Gel), to fabricate an electrospun scaffold. The fabricated samples underwent comprehensive physicochemical characterization, including SEM, FT-IR spectroscopy, tensile assay, and contact angle measurement. These optimized samples were subsequently employed for cell culture experiments. The average diameter of the prepared nanofibers ranged from 215.9 to 434.1 nm. FT-IR and DSC assays confirmed the physical blending of EW, PCL, and Gel without any occurrence of new chemical reactions. The contact angle test demonstrated a decrease in scaffold hydrophilicity from 26.25° to 116.5° with an increase in EW content within the PCL/Gel blend (0%-15%). Notably, the electrospun PCL/Gel nanofibrous mat containing 10% EW exhibited enhanced bioactivity compared to other samples with varying amounts of EW. Consequently, incorporating 10% EW into PCL/Gel nanofibers can significantly improve the efficiency of fibroblast culture. This research introduces a novel nanofibrous scaffold for skin tissue engineering, incorporating Gel and EW as low-cost and readily available materials, with great potential for various biological applications.
Pulsar kicks in ultralight dark matter background induced by neutrino oscillation
Authors: Lambiase Gaetano , Poddar Tanmay Kumar 
Published: January 2024

Abstract
The interaction of neutrinos with ultralight scalar and vector dark matter backgrounds induce a modification of the neutrino dispersion relation. The effects of this modification are reviewed in the framework of asymmetric emission of neutrinos from the supernova core, and, in turn, of pulsar kicks. We consider the neutrino oscillations, focusing in particular to active-sterile conversion. The ultralight dark matter induced neutrino dispersion relation contains a term of the form δ
Ω · p̂, where δ
Ω is related to the ultralight dark matter field and p̂ is the unit vector along the direction of neutrino momentum. The relative orientation of p with respect to δ
Ω affects the mechanism for the generation of the observed pulsar velocities. We obtain the resonance condition for the active-sterile neutrino oscillation in ultralight dark matter background and calculate the star parameters in the resonance surface so that both ultralight scalar and vector dark matter backgrounds can explain the observed pulsar kicks. The asymmetric emission of neutrinos in presence of ultralight dark matter background results gravitational memory signal which can be probed from the future gravitational wave detectors such as adLIGO (advanced LIGO), adVIRGO (advanced VIRGO), DECIGO (DECi-hertz Interferometer Gravitational wave Observatory), BBO (Big Bang Observer), and ET (Einstein Telescope). We also establish a relation between the ultralight dark matter parameters and the Lorentz and CPT invariance violation parameters.
Strong decays of the P
c(4312) and its isospin cousin via the QCD sum rules*
Authors: Wang Xiu-Wu , Wang 王 Zhi-Gang 志刚 
Published: January 2024

Abstract
In this study, considering the conservation of isospin in the strong decays, we investigate the strong decays of the pentaquark molecule candidate

and its possible higher isospin cousin

in the framework of the QCD sum rules. Further, the pole residue of the Δ baryon with isospin eigenstate

is obtained. If the possible pentaquark molecule candidate

could be determined, it would shed light on the interpretations of the

states in future experiments.
Prediction of cognitive conflict during unexpected robot behavior under different mental workload conditions in a physical human–robot collaboration
Authors: John Alka Rachel , Singh Avinash K , Gramann Klaus , Liu Dikai , Lin Chin-Teng 
Published: January 2024

Abstract

Objective. Brain–computer interface (BCI) technology is poised to play a prominent role in modern work environments, especially a collaborative environment where humans and machines work in close proximity, often with physical contact. In a physical human robot collaboration (pHRC), the robot performs complex motion sequences. Any unexpected robot behavior or faulty interaction might raise safety concerns. Error-related potentials, naturally generated by the brain when a human partner perceives an error, have been extensively employed in BCI as implicit human feedback to adapt robot behavior to facilitate a safe and intuitive interaction. However, the integration of BCI technology with error-related potential for robot control demands failure-free integration of highly uncertain electroencephalography (EEG) signals, particularly influenced by the physical and cognitive state of the user. As a higher workload on the user compromises their access to cognitive resources needed for error awareness, it is crucial to study how mental workload variations impact the error awareness as it might raise safety concerns in pHRC. In this study, we aim to study how cognitive workload affects the error awareness of a human user engaged in a pHRC. Approach. We designed a blasting task with an abrasive industrial robot and manipulated the mental workload with a secondary arithmetic task of varying difficulty. EEG data, perceived workload, task and physical performance were recorded from 24 participants moving the robot arm. The error condition was achieved by the unexpected stopping of the robot in 33% of trials. Main results. We observed a diminished amplitude for the prediction error negativity (PEN) and error positivity (Pe), indicating reduced error awareness with increasing mental workload. We further observed an increased frontal theta power and increasing trend in the central alpha and central beta power after the unexpected robot stopping compared to when the robot stopped correctly at the target. We also demonstrate that a popular convolution neural network model, EEGNet, could predict the amplitudes of PEN and Pe from the EEG data prior to the error. Significance. This prediction model could be instrumental in developing an online prediction model that could forewarn the system and operators of the diminished error awareness of the user, alluding to a potential safety breach in error-related potential-based BCI system for pHRC. Therefore, our work paves the way for embracing BCI technology in pHRC to optimally adapt the robot behavior for personalized user experience using real-time brain activity, enriching the quality of the interaction.
Improving the performance of P300-based BCIs by mitigating the effects of stimuli-related evoked potentials through regularized spatial filtering
Authors: Mobaien Ali , Boostani Reza , Sanei Saeid 
Published: January 2024

Abstract

Objective. the P300-based brain–computer interface (BCI) establishes a communication channel between the mind and a computer by translating brain signals into commands. These systems typically employ a visual oddball paradigm, where different objects (linked to specific commands) are randomly and frequently intensified. Upon observing the target object, users experience an elicitation of a P300 event-related potential in their electroencephalography (EEG). However, detecting the P300 signal can be challenging due to its very low signal-to-noise ratio (SNR), often compromised by the sequence of visual evoked potentials (VEPs) generated in the occipital regions of the brain in response to periodic visual stimuli. While various approaches have been explored to enhance the SNR of P300 signals, the impact of VEPs has been largely overlooked. The main objective of this study is to investigate how VEPs impact P300-based BCIs. Subsequently, the study aims to propose a method for EEG spatial filtering to alleviate the effect of VEPs and enhance the overall performance of these BCIs. Approach. our approach entails analyzing recorded EEG signals from visual P300-based BCIs through temporal, spectral, and spatial analysis techniques to identify the impact of VEPs. Subsequently, we introduce a regularized version of the xDAWN algorithm, a well-established spatial filter known for enhancing single-trial P300s. This aims to simultaneously enhance P300 signals and suppress VEPs, contributing to an improved overall signal quality. Main results. analyzing EEG signals shows that VEPs can significantly contaminate P300 signals, resulting in a decrease in the overall performance of P300-based BCIs. However, our proposed method for simultaneous enhancement of P300 and suppression of VEPs demonstrates improved performance in P300-based BCIs. This improvement is verified through several experiments conducted with real P300 data. Significance. this study focuses on the effects of VEPs on the performance of P300-based BCIs, a problem that has not been adequately addressed in previous studies. It opens up a new path for investigating these BCIs. Moreover, the proposed spatial filtering technique has the potential to further enhance the performance of these systems.
Ultrahigh neutral pressures in the sub-divertor of the Large Helical Device
Authors: Wenzel U. , Motojima G. , Kobayashi M. , Goto M. , Hayashi Y. , Masuzaki S. , Kawamura G. , Jagielski B. , Haak V. 
Published: January 2024

Abstract
In the Large Helical Device (LHD) a low temperature mode (LTM) of the helical divertor was discovered. It combines particle detachment and very large sub-divertor pressures up to 1.4 Pa. During the LTM, the electron temperature in the divertor was in the range from 0.25 to 0.42 eV so that volume recombination occurred. This result is remarkable because in the stellarators LHD and Wendelstein 7-X only low sub-divertor pressures (0.03–0.3 Pa) were expected and measured up to now due the loss of pressure conservation along flux tubes by an enhanced cross-field transport. It demonstrates that the more complex, three-dimensional divertors of stellarators can achieve a similar performance with respect to particle exhaust and detachment like the geometrically simpler poloidal divertors in tokamaks even if the favorable effect of flux amplification is absent. The LTM of the helical divertor depends, however, on the magnetic configuration, i.e. on geometry. It was only observed in the inward shifted configuration with

R

a
x

=
3.55

m, but not in the more frequently studied configuration with

R

a
x

=
3.6

m. A nuclear fusion reactor based on the heliotron concept (DEMO) would benefit from the LTM by the very compact divertor configuration and the excellent performance.