bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantifying the accuracy of inter-beat intervals acquired from consumer-grade photoplethysmography wristbands using an electrocardiogram-aided information-based similarity approach
Authors: Cui Xingran , Wang Jing , Xue Shan , Qin Zeguang , Peng Chung-Kang 
Published: February 2024

Abstract

Objective. Although inter-beat intervals (IBI) and the derived heart rate variability (HRV) can be acquired through consumer-grade photoplethysmography (PPG) wristbands and have been applied in a variety of physiological and psychophysiological conditions, their accuracy is still unsatisfactory. Approach. In this study, 30 healthy participants concurrently wore two wristbands (E4 and Honor 5) and a gold-standard electrocardiogram (ECG) device under four conditions: resting, deep breathing with a frequency of 0.17 Hz and 0.1 Hz, and mental stress tasks. To quantitatively validate the accuracy of IBI acquired from PPG wristbands, this study proposed to apply an information-based similarity (IBS) approach to quantify the pattern similarity of the underlying dynamical temporal structures embedded in IBI time series simultaneously recorded using PPG wristbands and the ECG system. The occurrence frequency of basic patterns and their rankings were analyzed to calculate the IBS distance from gold-standard IBI, and to further calculate the signal-to-noise ratio (SNR) of the wristband IBI time series. Main results. The accuracies of both HRV and mental state classification were not satisfactory due to the low SNR in the wristband IBI. However, by rejecting data segments of SNR < 25, the Pearson correlation coefficients between the wristbands' HRV and the gold-standard HRV were increased from 0.542 ± 0.235 to 0.922 ± 0.120 for E4 and from 0.596 ± 0.227 to 0.859 ± 0.145 for Honor 5. The average accuracy of four-class mental state classification increased from 77.3% to 81.9% for E4 and from 79.3% to 83.3% for Honor 5. Significance. Consumer-grade PPG wristbands are acceptable for HR and HRV monitoring when removing low SNR segments. The proposed method can be applied for quantifying the accuracies of IBI and HRV indices acquired via any non-ECG system.
A differentiable actuator extends potential configurations of modular robots
Authors: Li Henghao , Zhang Xiaolin , Liang Weijian , Xiao Endong , Huang Wenkai 
Published: February 2024

Abstract
Mesenchymal stem cells (MSCs) can be differentiated into various cell lineages under the influence of mechano-niche. Inspired by this approach, this study presents a differentiable stem cell actuator unit (SAU) driven by a shape memory alloy, and a modular robotic framework. Similar to mechanically guided differentiation of MSCs, SAUs can be differentiated into a series of differentiated actuator units (DAUs) under external preload. This process has been modeled, simulated, and experimentally validated, with testing conducted on three distinct types and 14 specifications of DAUs. DAUs weighing as light as 1.96g exhibited outputs reaching up to 10.6 N and 46.32 Nmm. Our team has developed seven application prototypes based on this bio-inspired framework including mobile robots, manipulators and end effectors. This work pioneers the integration of differentiable concepts and principles into the design of modular robots, enabling a wider range of potential configurations and capabilities.
High-efficient and intelligent antibacterial face mask integrated with airflow-temperature dual-function sensors for respiratory monitoring and disease prevention
Authors: Lan Xingzi , Chen Xinyu , Chen Xin , Fan Hao , Zheng Hehui , Wang Han , Tang Yadong 
Published: February 2024

Abstract
Intelligent face masks play crucial roles in health monitoring and disease prevention, having attracted huge attention in recent years. However, most of the current intelligent face masks focus on monitoring single physical signal, which were unable to provide comprehensive information. Herein, an intelligent face mask with airflow and temperature sensing abilities, high-efficiency filtration and excellent antibacterial activity was proposed. The real-time airflow monitoring was realized by a triboelectric nanogenerator (TENG), which was composed of electrospun nanofibrous membrane and polydimethylsiloxane (PDMS) composite film. The fabricated electrospun nanofibrous membrane simultaneously played roles as tribo-positive material, filter and antibacterial membrane. The PDMS composite film prepared by co-blending and surface modification was applied as tribo-negative material. It was found that the combination of co-blending and surface modification enhanced the tribo-negative property of the PDMS film, resulting in an increment of output performance of TENG. The TENG integrated into a face mask could monitor respiratory rate and respiration intensity in real time. Additionally, the temperature sensing was achieved by a serpentine PDMS/laser-induced graphene temperature sensor. The temperature sensor exhibited a temperature coefficient of resistance of 0.316% °C−1, which could detect subtle temperature variations. Furthermore, the electrospun nanofibrous membrane exhibited excellent filtration performance and antibacterial activity. Therefore, the prepared intelligent face mask showed promising potential for healthcare applications.
A phase-transition model of reprocessible thermadapt shape memory polymer
Authors: Mu Tong , Jia Fei , Zhao Wei , Liu Yanju , Leng Jinsong 
Published: February 2024

Abstract
A new type of thermadapt shape memory polymer (SMP) has not only the processability of thermoplastic SMP, but also the excellent shape fixation of thermosetting SMP. To enhance the application of this thermadapt SMP within industrial sectors, a comprehensive constitutive model based on phase transition is being proposed as an indicative descriptor of the semi-crystalline thermadapt SMP’s salient features, predominantly related to its two-way shape memory effect (SME) and thermal reprocessability. The concept of cooling elongation is also introduced in this model for modeling the two-way SME during the crystallization process. The molecular mechanism of chain-packing has been studied and used to establish phenomenological formulas. In addition, to systematically assess the temperature-time dependence of the crystallization process, the Avrami equation is improved by incorporating the distribution of polymer chain segments. This strategy provides a detailed investigation into the evolving pattern of the crystallization process in response to various temperature and time conditions. Compared with the experimental results, it is found that our model can well capture mechanical behavior in multiple shape memory cycles, including the two-way SME and reshaping process caused by bond exchange reaction. Furthermore, the potential application of SMP in smart mandrels is explored because the cooling elongation feature is able to endow it with self-adaptive expansion ability.
Light-induced nonlinear spin Hall current in single-layer WTe2
Authors: Bhalla Pankaj , Rostami Habib 
Published: February 2024

Abstract
In this theoretical investigation, we analyze light-induced nonlinear spin Hall currents in a gated single-layer 1T

′

-WTe2, flowing transversely to the incident laser polarization direction. Our study encompasses the exploration of the second and third-order rectified spin Hall currents using an effective low-energy Hamiltonian and employing the Kubo’s formalism. We extend our analysis to a wide frequency range spanning both transparent and absorbing regimes, investigating the influence of light frequency below and above the optical band gap. Additionally, we investigate the influence of an out-of-plane gate potential on the system, disrupting inversion symmetry and effectively manipulating both the strength and sign of nonlinear spin Hall responses. We predict a pronounced third-order spin Hall current relative to its second-order counterpart. The predicted nonlinear spin currents show strong anisotropic dependence on the laser polarization angle. The outcomes of our study contribute to a generalized framework for nonlinear response theory within the spin channel will impact the development of emerging field of opto-spintronic.
Classical-quantum correspondence for particles in the Penning trap
Authors: Bialynicki-Birula Iwo , Bialynicka-Birula Zofia 
Published: February 2024

Abstract
We derive new solutions of the Schrödinger equation which describe the motion of particles in the Penning trap. These solutions are direct counterparts of classical orbits. They are obtained by injection of classical trajectories into the wave functions of stationary solutions.
Strong convergence theorem for split null point, split variational inequality and fixed point problems for a non-expansive semigroup
Authors: Husain Shamshad , Khairoowala Mubashshir U , Furkan Mohd 
Published: February 2024

Abstract
The primary goal of this paper is to find a common solution of a split null point problem, split variational inequality problem and fixed point problem for a non-expansive semigroup with the help of new type of iterative algorithm. We construct that the sequences induced by the proposed iterative method to solve the above stated problems in the setting of real Hilbert spaces and obtain a strong convergence theorem. We also deduce certain consequences from the main convergence result. At the end, we provide a numerical experiment to demonstrate the convergence analysis of proposed iterative method. The methodology and conclusion described in this work extend and unify previously published findings in this field.
Study of viable compact stellar structures in non-Riemannian geometry
Authors: Gul M Zeeshan , Sharif M , Arooj Adeeba 
Published: February 2024

Abstract
The main objective of this article is to study the viable compact stellar structures in non-Riemannian geometry, i.e.,

f
(
Q
,
T
)

theory, where

Q

defines the non-metricity and T represents trace of the stress-energy tensor. In this perspective, we consider a static spherical metric with anisotropic matter configuration to examine the geometry of considered compact stars. A specific model of this theory is used to derive the explicit expressions of energy density and pressure components that govern the relationship between matter and geometry. The unknown parameters are evaluated by using the continuity of inner and outer spacetimes to examine the configuration of spherical stellar structures. Physical parameters such as fluid characteristics, energy constraints and equation of state parameters are analyzed to examine the viability of the considered stellar objects. Further, we use Tolman-Oppenheimer-Volkoff equation, sound speed and adiabatic index methods to analyze the equilibrium state and stability of the proposed stellar objects. The rigorous analysis and satisfaction of necessary conditions lead to the conclusion that the stellar objects studied in this framework are viable and stable.
Raychaudhuri equation and the dynamics of cosmic evolution
Authors: Chakraborty Madhukrishna , Chakraborty Subenoy 
Published: February 2024

Abstract
The paper deals with the Raychaudhuri equation (RE) which is a non-linear ordinary differential equation in Θ, the expansion scalar corresponding to a geodesic flow. Focusing theorem which follows as a consequence of the RE has been restated in terms of the cosmic parameter q (deceleration parameter) both for Einstein gravity and for modified gravity theories. Measurable quantities namely the luminosity distance and density parameter are shown to have an upper bound using the Raychaudhuri scalar. An analogy between geometric and cosmological RE has been made. Subsequently, to find the solution of the non-linear RE a transformation of variable related to the metric scalar of the hyper-surface has been identified which converts the former to a second order differential equation. Finally, the first integral of this second order differential equation gives the entire picture of the dynamics of cosmic evolution
Primordial black holes dark matter and secondary gravitational waves from warm Higgs-G inflation
Authors: Arya Richa , Jain Rajeev Kumar , Mishra Arvind Kumar 
Published: February 2024

Abstract
We explore the role of dissipative effects during warm inflation leading to the small-scale enhancement of the power spectrum of curvature perturbations. In this paper, we specifically focus on non-canonical warm inflationary scenarios and study a model of warm Higgs-G inflation, in which the Standard Model Higgs boson drives inflation, with a Galileon-like non-linear kinetic term.
We show that in the Galileon-dominated regime, the primordial power spectrum is strongly enhanced, leading to the formation of primordial black holes (PBH) with a wide range of the mass spectrum.
Interestingly, PBHs in the asteroid mass window ∼ (1017–1023) g are generated in this model, which can explain the total abundance of dark matter in the Universe.
In our analysis, we also calculate the secondary gravitational waves (GW) sourced by these small-scale overdense fluctuations and find that the induced GW spectrum can be detected in future GW detectors, such as LISA, BBO, DECIGO, etc. Our scenario thus provides a novel way of generating PBHs as dark matter and a detectable stochastic GW background from warm inflation. We also show that our scenario is consistent with the swampland and the trans-Planckian censorship conjectures and, thus, remains in the viable landscape of UV complete theories.
Shedding light on neutrino self-interactions with solar antineutrino searches
Authors: Wu Quan-feng , Xu Xun-Jie 
Published: February 2024

Abstract
Solar antineutrinos are absent in the standard solar model prediction. Consequently, solar
antineutrino searches emerge as a powerful tool to probe new physics capable of converting
neutrinos into antineutrinos. In this study, we highlight that neutrino self-interactions,
recently gaining considerable attention due to their cosmological and astrophysical implications,
can lead to significant solar antineutrino production. We systematically explore various types of
four-fermion effective operators and light scalar mediators for neutrino self-interactions. By
estimating the energy spectra and event rates of solar antineutrinos at prospective neutrino
detectors such as JUNO, Hyper-Kamiokande, and THEIA, we reveal that solar antineutrino searches
can impose stringent constraints on neutrino self-interactions and probe the parameter space
favored by the Hubble tension.
The International Astronomical Search Collaboration (IASC)—Citizen Scientist System for Asteroid Discovery
Authors: Miller Patrick , Weryk Robert , Wainscoat Richard , Perret Jules , Hartung Steve , Vorobjov Tomas , Buzzi Luca , Raab Herbert , Chastel Serge , Fairlamb John , Huber Mark , Ramanjooloo Yudish , Chambers Kenneth , de Boer Thomas , Gao Hua , Lin Roger Chien-Cheng , Magnier Eugene , Pennypacker Carlton 
Published: February 2024

Abstract
We describe a citizen science asteroid detection system developed by the International Astronomical Search Collaboration (IASC) and the Institute for Astronomy at the University of Hawaii, utilizing data from the Pan-STARRS telescopes. The goals of this project are to (i) educate and engage citizen scientists (mostly high school students) in science and astronomy, (ii) search for new asteroids to extend the limiting magnitudes of existing asteroid surveys, and (iii) find missed Near-Earth Objects (NEOs—objects with perihelia q < 1.3 au) to support planetary defense efforts. Over the past 15 yr, 50,000 citizen scientists from 96 countries around the world have detected ∼12,000 main-belt asteroids and ∼5 NEOs. Citizen scientists use the software Astrometrica during scheduled campaigns to search for and measure asteroid astrometry and photometry, and submit the data to IASC for vetting. Candidate detections not already submitted by Pan-STARRS are then submitted to the Minor Planet Center, and are typically ∼0.30 ± 0.07 mag fainter.
Hybrid modeling and optimization of fiber laser hole cutting of austenitic stainless-steel sheets using response surface
Authors: Niu Zhenhua , Dehkordi Mohammad Hossein Razavi , Ghazi Mohammadreza , Akbari Mohammad 
Published: February 2024

Abstract
In this study, an efficient approach was proposed to systematically model and optimize the laser small hole cutting process parameters using a hybrid approach for the design of experiment and multi-objective genetic algorithm optimization. The central composite design and response surface methodology were used to effectively model the impact of four main factors: cutting speed, laser power, gas pressure and focal distance on the responses. The responses considered were hole diameter circularity tolerance, spattering and cut kerf width, which were used to evaluate the quality of the laser hole cutting. The regression equations were used to model the effect of process parameters and their interactions on the responses. These regression models were then used as objective functions for optimization. The results show that the focal distance and laser power have had a significant influence on the hole diameter circularity tolerance and the variation in size of the cut kerf. In particular, the melted material spattering rate increased threefold when the focal distance increased from 0.4 to 0.8 mm. The optimization results highlighted that the best outcomes in terms of minimum deviation, spatter, and the cut-kerf width were achieved at low power (between 605 and 685 W) and low speeds (in the range of 11.1–12.7 m min−1). The optimal focal distance for all solutions was found to be 0 mm for the gas pressure (between 6.5 and 8 bars) to minimize the objective functions.
Influence of environmental conditions on the degradation of rubber compounds
Authors: Markovičová L , Zatkalíková V 
Published: February 2024

Abstract
Rubber compounds are complex, chemically active and viscoelastic materials. In this material type, transient and transient changes in the individual rubber properties occur during the manufacturing processes. A large number of rubber compounds consist of a large number of elastomers and virtually all of them are made up of fillers such as (carbon black, silica, kaolin, calcium carbonate, etc.). A very important element of which rubber compounds are composed is sulphur. Its important function is to ensure the cross-linking process during vulcanisation. Lubricants, plasticizers and various organic substances used to modify the properties are also essential components of rubber compounds. The aim of this work is to assess the influence of natural environmental conditions (temperature, time, humidity, microorganisms, UV radiation) on the modification of the properties of rubber composites.
The effect of long-term exposure in mixed sulfuric acid and copper sulfate solution on corrosion behavior of austenitic stainless steels
Authors: Zatkalíková V , Markovičová L 
Published: February 2024

Abstract
Corrosion resistance of austenitic stainless steels in sulfuric acid solutions depends mainly on concentration and temperature of the sulfuric acid, the presence of contaminants and velocity flow. Current studies aim mostly at evaluation of electrochemical parameters in sulfuric acid solutions. Research focused on long-term exposure is lacking. This article deals with the corrosion behavior of AISI 304 and AISI 316L stainless steels in mixed 10 wt. % sulfuric acid and 10 wt. % copper sulfate solution. Sensitized (650 °C/40 hours) and solution annealed (1050 °C/15 min) specimens together with the untreated (as received) ones are evaluated by long-term (22-month) exposure immersion test at the temperature of 22 ± 3 °C on the bases of optical microscopy, SEM and mass losses. Both tested stainless steels in as received and solution annealed state proved high corrosion resistance in the given corrosive environment. The cross-sections edges of sensitized specimens revealed a close relationship between local corrosion sites and weakened grain boundaries, which indicates incipient intergranular corrosion.
Analysis of Biocompatible Metallic Materials used in Medicine
Authors: Gerhátová Ž , Paták J , Babincová P , Hudáková M , Palcut M 
Published: February 2024

Abstract
The paper presents the results of the analysis of two biocompatible materials, Kirschner wires of different thicknesses. Kirschner wires (K-wires) are stainless steel pins used in surgery to fix bone fragments and to provide an anchor for skeletal traction. The K-wires are produced in different diameters. In the present work, a scanning electron microscopy and light microscopy were employed to document the microstructure of two K-wires with different thicknesses. Before observation, the wires were prepared by a standard metallographic procedure (grinding and polishing) followed by electrolytic etching. The chemical composition was determined by studying the wires using quantitative energy-dispersive X-ray spectrometry. It has been found that the chemical composition of the materials corresponds to Cr-Ni stainless steel. In the thick Kirschner wire (sample no. 1) a deformed microstructure after drawing was observed. Sample no. 2 (thin Kirschner wire), on the other hand, consisted of polyhedral austenitic grains, which were formed after recrystallization annealing. Furthermore, isolated microparticles were observed and assigned to titanium nitride. A Vickers hardness test was also performed on the samples. It has been found that the hardness of sample no. 1 was 428.8 HV 0.5. The average hardness of sample no. 2 was 213.4 HV 0.5. It can be concluded that recrystallization annealing decreases the hardness of the material. The K-wires with smaller diameter are thus easier to bend which facilitates their fixation in human body.
Statistical evaluation of hard-to-measure surfaces
Authors: Kubišová M , Knedlová J , Vrbová H , Pata V , Bočáková B 
Published: February 2024

Abstract
The main goal of this article will be to find ways to evaluate hard-to-measure surfaces statistically. First, the basic characteristics and rules of surface quality will be described according to the standards ČSN EN 4287, ČSN EN 4288 and ČSN EN ISO 2517-2. Subsequently, the measured values of the roughness parameter Sa (arithmetic average of the height of the measured surface) and Sz (the maximum height of the measured surface) will be compared and evaluated which is the best. These parameters will be described and measured on aluminium plates on which the test surfaces were laser engraved. To evaluate the best surface, statistical methods will be used, such as the EDA methodology (exploratory data analysis), hypothesis testing with normality and outlier tests, and last but not least, cluster or cluster analysis, which compares the similarity of the measured data. This article aims to show the possibilities of surface quality assessment using 3D surface roughness parameters, which are not often used in practice.