bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anthropometric characteristics according to the role performed by World Tour road cyclists for their team
Authors: Sánchez‐Muñoz C. , Mateo‐March M. , Muros J. J. , Javaloyes A. , Zabala M. 
Published: October 2022

ABSTRACTCertain anthropometric characteristics are required for athletes to successfully perform in elite endurance sports. The present study aims to analyse the anthropometric characteristics of professional cyclists according to their specialty. Anthropometric measurements were conducted of the body composition of 76 male professional road cyclists in line with International Society for Advancement of Kinanthropometry protocol. Fat mass did not differ (p > 0.05) between climbers, all‐rounders and flat specialists, although the following anthropometric variables did differ according to the role played within the team (p < 0.05): Body mass (climbers: 63.8 ± 3.6, all‐rounders: 68.8 ± 5.3, flat specialists: 74.5 ± 5.6 kg) skeletal body mass (climbers: 29.7 ± 1.6, all‐rounders: 31.4 ± 1.9, flat specialists: 33.5 ± 2.4 kg); body surface area (climbers: 1.78 ± 0.07, all‐rounders: 1.89 ± 0.10, flat specialists: 1.96 ± 0.1 m2); frontal area (climbers: 0.33 ± 0.01, all‐rounders: 0.35 ± 0.02, flat specialists: 0.36 ± 0.02 m2). Anthropometric characteristics differ between world‐class cyclists depending on their specialty. These differences could influence performance in relation to different types of road cycling competitions. The present study identified characteristics that could be used by coaches to evaluate their athletes in the context of elite or professional road cycling.
Wald’s entropy in Coincident General Relativity
Authors: Heisenberg Lavinia , Kuhn Simon , Walleghem Laurens 
Published: October 2022

Abstract
The equivalence principle and its universality enables the geometrical formulation of gravity. In the standard formulation of General Relativity (GR) á la Einstein, the gravitational interaction is geometrized in terms of the spacetime curvature. However, if we embrace the geometrical character of gravity, two alternative, though equivalent, formulations of GR emerge in flat spacetimes, in which gravity is fully ascribed either to torsion or to non-metricity. The latter allows a much simpler formulation of GR oblivious to the affine spacetime structure, the Coincident General Relativity (CGR). The entropy of a black hole can be computed using the Euclidean path integral approach, which strongly relies on the addition of boundary or regulating terms in the standard formulation of GR. A more fundamental derivation can be performed using Wald’s formula, in which the entropy is directly related to Noether charges and is applicable to general theories with diffeomorphism invariance. In this work we extend Wald’s Noether charge method for calculating black hole entropy to spacetimes endowed with non-metricity. Using this method, we show that CGR with an improved action principle gives the same entropy as the well-known entropy in standard GR. Furthermore the first law of black hole thermodynamics holds and an explicit expression for the energy appearing in the first law is obtained.
Null and timelike circular orbits from equivalent 2D metrics
Authors: Cunha Pedro V P , Herdeiro Carlos A R , Novo João P A 
Published: October 2022

Abstract
The motion of particles on spherical

1
+
3

dimensional spacetimes can, under some assumptions, be described by the curves on a two-dimensional manifold, the optical and Jacobi manifolds for null and timelike curves, respectively. In this paper we resort to auxiliary two-dimensional metrics to study circular geodesics of generic static, spherically symmetric, and asymptotically flat

1
+
3

dimensional spacetimes, whose functions are at least C
2 smooth. This is done by studying the Gaussian curvature of the bidimensional equivalent manifold as well as the geodesic curvature of circular paths on these. This study considers both null and timelike circular geodesics. The study of null geodesics through the optical manifold retrieves the known result of the number of light rings on the spacetime outside a black hole and on spacetimes with horizonless compact objects. With an equivalent procedure we can formulate a similar theorem on the number of marginally stable timelike circular orbits of a given spacetime satisfying the previously mentioned assumptions.
The stability of galaxies in an expanding Universe obtained by Newtonian dynamics
Authors: Toxvaerd Søren 
Published: October 2022

AbstractThe dynamics of galaxies in an expanding Universe is often determined for gravitational and dark matter in an Einstein-de Sitter Universe, or alternatively by modifying the gravitational long-range attractions in the Newtonian dynamics. Here the time evolution of galaxies is determined by simulations of systems with pure gravitational forces by classical molecular dynamic simulations. A time reversible algorithm for formation and aging of gravitational systems by self-assembly of baryonic objects, recently derived (Toxvaerd 2022Eur. Phys. J. Plus13799), is extended to include the Hubble expansion of the space. The algorithm is stable for billions of time steps without any adjustments. The algorithm is used to simulate simple models of the Milky Way with the Hubble expansion of the Universe, and the galaxies are simulated for times which corresponds to more than 25 Gyr. The rotating galaxies lose bound objects from time to time, but they are still stable at the end of the simulations. The simulations indicate that the explanation for the dynamics of galaxies may be that the Universe is very young in cosmological times. Although the models of the Milky Way are rather stable at 13–14 Gyr, which corresponds to the cosmological time of the Universe, the Hubble expansion will sooner or later release the objects in the galaxies. But the simulations indicate that this will first happen in a far away future.
Thermodynamics of a particle in square well potential
Authors: Bhattacharyya Satadal , Mitra Joydip 
Published: October 2022

Abstract
We have presented the thermodynamic properties of a particle moving freely both in an infinite and finite square well in contact with a heat reservoir at constant temperature. In both cases, we have computed the temperature dependence of the partition function, entropy, average energy and specific heat of the particle in an exact way. The exact results for various thermodynamic parameters deviate considerably from its known theoretical values and reveal the importance of such calculations. The effect of the width of the finite well on the different thermodynamic quantities have also been examined critically.
A fault diagnosis method for rolling bearings based on RDDAN under multivariable working conditions
Authors: Shi Huaitao , Gan Chunxia , Zhang Xiaochen , Meng Weiying , Huang Chengzhuang 
Published: October 2022

Abstract
Mechanical equipment in actual motion can produce noise interference with the vibration signal of rolling bearings, which have non-constant loads and speed. These factors lead to variable and unstable vibration signals of rolling bearings; therefore, it is very difficult to accurately diagnose actual running rolling bearings. In this paper, a residual denoising dynamic adaptation network (RDDAN) is proposed, which uses the signal knowledge under known working conditions to diagnose rolling bearing faults under unknown working conditions. The method mainly consists of data preprocessing, feature extraction, and dynamic distribution adaptation. First, Gaussian noise is added at the data preprocessing stage to emulate the noise perturbation during the reality of rolling bearing operation. Secondly, a deep residual shrinkage network is used for noise reduction and feature extraction. Finally, the marginal probability distribution and conditional probability distribution under different working conditions are calculated, depending on the characteristics. The network is disciplined using the relative weight of the marginal probability distribution and the conditional probability distribution. And the fault classification results are output after multiple iterations. The method was tested on the Case Western Reserve University bearing dataset and the Machine Fault Simulator Magnum bearing dataset, respectively. In comparison with other models, the RDDAN improves the average accuracy by about 23%. The results show that the RDDAN can effectively solve the problem of inconsistent data distribution in rolling bearings under operating conditions influenced by multiple variables such as noise, load, and speed.
An intelligent ultrasonic guided wave deep imaging detection method considering the propagation characteristics of each direction
Authors: Zhang Bin , Chen Zhuyun , Yang Dingmin , Hong Xiaobin , Jin Gang 
Published: October 2022

Abstract
Macroscopic damage in multilayer anisotropic structures is usually formed by the rapid development of material micro-damage. The existing micro-damage imaging detection technology does not consider the difference of wave velocity in all directions of the detection structure, especially not directly taking the wave velocities in different direction into the imaging counting process, the micro-damage imaging detection, and the false detection rate and missed detection rate are high. In this paper, a deep learning imaging detection method considering velocity in all directions is proposed and verified on a carbon fiber anticorrosive coating structure of a shaftless ring propeller drive system. Firstly, the problem that the elliptical damage path cannot be determined in the anisotropic structure is analyzed, and the omnidirectional velocity of the carbon fibre reinforced plastics structure is obtained through simulation analysis. A new omni-directional imaging method was proposed, which discretized the monitored objects and acquired the damage index through deep learning network. The damage propagation time of the reference point was compared with that of the actual damage point to determine the damage probability of the structure. The experimental results show that the omni-directional imaging method can accurately and intuitively display the damage information of anisotropic structures.
Calibration of 3D scan trajectories for an industrial computed tomography setup with 6-DOF object manipulator system using a single sphere
Authors: Butzhammer Lorenz , Müller Andreas Michael , Hausotte Tino 
Published: October 2022

AbstractIn industrial x-ray computed tomography (CT), the application of more complex scan paths in comparison to the typical circular trajectory (360∘rotation of the measurement object) can extend the potential of CT. One way to enable such 3D scan trajectories is to use a 6-degrees-of-freedom (DOF) object manipulator system. In our case, a hexapod is mounted on top of the rotary table of a commercial CT scanner. This allows for adaptive tilting of the measurement object during the scan. For high accuracy, the geometry calibration of such setups is typically done using the x-ray projections of a calibrated multi-sphere object. Contrary to this, here, we demonstrate a procedure that is based on only a single sphere and can therefore experimentally be implemented with low effort. Using the intrinsic geometry parameters of the CT device as prior information, the hexapod coordinate system with respect to the CT machine coordinate system is determined by means of a one-step optimization approach. The resulting parameters are used to calculate projection matrices that enable the volume reconstruction for 3D scan trajectories. The method is validated using simulated x-ray images and experimental investigations including dimensional measurements. For the used setup, geometric measurement results for 3D scan trajectories that are calibrated with the presented method show in sum increased errors compared to the circular scans. A limited pose accuracy of the manipulator system is discussed as a potential cause. The results nevertheless indicate that the presented method is generally feasible for dimensional CT measurements provided that the pose accuracy is sufficient. The calibration procedure can therefore be a low-cost and easier to implement alternative compared to trajectory calibration methods based on multi-sphere objects, but with a tendency towards lower measurement accuracy. The methodology can in principle be transferred to different setups with 6-DOF manipulator systems, e.g. C-arm CT devices with a robot arm.
Numerical modelling for beam duct heat loads calculations and application to the new 1 MW neutral beam injector in the COMPASS tokamak
Authors: Jaulmes F , Zadvitskiy G , Bogar K , Mysiura I , Varju J , Jeřáb M , Komm M , Imrisek M 
Published: October 2022

Abstract
We introduce detailed numerical modelling of the fast neutral particles inside the duct of a new neutral beam injector (NBI) recently installed at the COMPASS tokamak (major radius

R
0

=
0.56

m

, vessel midplane minor radius

a
=
0.23

m

, toroidal field

B

t

= 0.9–2.1

T

). This new NBI system is able to deliver

1

M
W

power to the plasma at nominal injection energy of

80

k
e
V

. Collisions with the background neutrals inside the beam duct give birth to fast ions according to the density of the gas and tabulated cross-sections. The ion trajectories are then computed in the complete 3D magnetic field, showing the importance of the stray magnetic field and the magnitude of the field within the gap in between toroidal coils.During the experimental campaign dedicated to the new 1 MW NBI, the beam duct heating was measured by a row of thermocouples located on the top-half of the beam duct. The fast ions collisions with the duct wall cause a local temperature increase with a characteristic pattern. In COMPASS, the location of the fast ions power deposition measured experimentally is in qualitative agreement with modelling of ion losses when following them after the re-ionization process. We trace back the details of the orbits corresponding to deposition at the hot-spot inside the beam duct. Quantitative comparison between the experiment and the simulation shows that a larger than expected amount of neutral gas was inside the duct and this study will guide the design of the future NBI duct in COMPASS Upgrade.
Intersection of 4H-SiC Schottky diodes I–V curves due to temperature dependent series resistance
Authors: Osvald J 
Published: October 2022

Abstract
We theoretically and experimentally analyzed the non-obvious intersections of Schottky diode I–V curves measured at different temperatures caused by increasing the series resistance of the diode with increasing temperature. We considered a homogeneous diode and an inhomogeneous diode with two ways of influencing the I–V curve by the series resistance. In each case we developed a numerical method that enabled anticipation of the I–V intersection point. We studied the Ni/Au/4H-SiC diode for which such an intersection was measured. For homogeneous diodes and temperature interval 300–400 K we found a voltage dispersion of intersection points of only ∼0.002 V, which is in accordance with experimental observations and suppositions in the literature that the curves intersect at almost the same I–V point. Even for an inhomogeneous diode with a common series resistance we obtained a dispersion of the intersection voltage of only ∼0.02 V which is hardly discernible by the common visualization of the I–V curves. The largest dispersion of intersection points was obtained for an inhomogeneous diode composed of non-interacting diode patches.
Semiconductor laser design with an asymmetric large optical cavity waveguide and a bulk active layer near p-cladding for efficient high-power red light emission
Authors: Avrutin Eugene A , Ryvkin Boris S 
Published: October 2022

Abstract
A semiconductor laser design for efficient, high power, high brightness red light emission is proposed, using a large optical cavity asymmetric waveguide and a bulk active layer (AL) positioned very close to the p-cladding. The low threshold carrier density associated with the broad AL, as well as the proximity of the AL to the p-cladding, ensure that the electron leakage current, the major detrimental factor in red lasers, stays modest in a broad range of excitation levels. This in turn promises high-power, efficient operation.
Influence of environmental conditions and voltage application on the electromechanical performance of Nafion-Pt IPMC actuators
Authors: Arnold Allison M , Su Ji , Sabolsky Edward M 
Published: October 2022

Abstract
Ionic polymer–metal composites (IPMCs) are a class of ionic-type electroactive polymers which can be configured as capacitor actuators with very low voltage requirements (⩽5 V AC or DC). Their compact, portable, and lightweight properties, coupled with a biomimetic bending actuation response, makes them ideal for human–machine integrated technologies such as medical implants, active skins, and artificial muscles. Unfortunately, IPMC actuator’s hydration-related sensitivity inhibits practical application in industry and makes experimental research difficult. Therefore, this research sought to quantify the hydration-related parameters of IPMC actuators by applying a wide range of experimental tests to characterize the material’s hydration-dependent features. This included saturation, dielectric, and bending actuation measurements. The IPMC’s degree of saturation properties were classified to establish sample rehydration, preparation, and preservation techniques. IPMC electrical-solvent properties were measured to estimate IPMC actuation performance based on capacitance and dissipation measurements. Maximized actuation was identified for samples tested in 95% RH (i.e. percentage relative humidity). This condition produced an optimized displacement range and retained quality. Through statistical analysis, the work showed large electroactive performance variability (up to 50% deviation), which is a primary obstacle inhibiting this technology from practical application. Finally, an array of electrical field bias applications (i.e. cycled, constant, and post voltage removal monitoring) at intensities ranging from 0.75 to 1.2 V (direct current voltage) were used to quantify actuation rate, maximum displacement, as well as voltage application and removal back-relaxation behavior.
Effects of substrate temperature on the growth of CuO nano/micro rods by ion beam sputter deposition
Authors: Ejigu Assamen Ayalew 
Published: October 2022

Abstract
CuO nano/micro rods were deposited on Si substrates by ion beam sputter deposition at substrate temperatures 300 °C, 350 °C, 400 °C and 450 °C. The effects of changing substrate temperature on the structural properties and surface morphology of the deposited CuO nano/micro rods were studied. Field Emission Scanning Electron Microscopy micrographs showed that at substrate temperature of 300 °C and 350 °C, tiny nanoparticles were observed on the surface of CuO thin films and at substrate temperature of 400 °C and 450 °C, CuO nano/micro rods of lengths (100 nm to 1 μm) and diameters (25 nm to 30 nm) observed in a periodic arrangement. X-Ray Diffraction (XRD) analysis showed that all the diffraction peaks of the samples were single-crystalline CuO corresponded to (

1

¯

11

) orientation. From the crystallographic analysis using XRD data, crystallite sizes of the samples increased (18 to 32 nm) with the increase of substrate temperature. The Micro-Raman spectroscopy investigation shows that all the Raman peaks observed were phonon modes of CuO and as the substrate temperature increased, the intensities of the Rama peaks increased. Hence, by changing substrate temperatures, it is possible to deposit high quality CuO nano/micro thin films with tunable structures, morphologies and sizes for different optoelectronic applications through ion beam sputter deposition.
Synthesis and characterization of GaN/quartz nanostructure using pulsed laser ablation in liquid
Authors: Fakhri Makram A , Alwahib Ali A , Salim Evan T , Abdul Amir Husam Aldin A , Alsultany Forat H , Hashim U 
Published: October 2022

AbstractThe pulsed laser ablation in liquid approach was used to synthesize gallium nitride (GaN) nanoparticles (NPs) at six distinct ablation energies. GaN target with purity of 99.999% submerged in 5 ml ethanol of 99.99% purty and fired with a Nd:YAG pulsed laser. The nanoparticle was deposited on a quartz substrate using the drop cast technique. Two peaks of h-GaN nanostructures are detected in the XRD pattern, at 2θ = 34.64 and 37.98, reflected from the (002) and (100) planes, respectively. The hexagonal crystal nature of GaN is indicated by the structural features, which is shown in the XRD pattern. The greatest laser power, 2000 mJ, shows a modest emission peaking at 3.34 eV, according to photoluminescence (PL) spectra. At 1400 mJ, the highest emission peak was 3.83 eV. The pulsed laser is used in this study to create nanoparticles with various characteristics.
Wave mixing efficiency in InAs/GaAs semiconductor quantum dot optical amplifiers and lasers
Authors: Renaud Thibaut , Huang Heming , Grillot Frédéric , Bimberg Dieter 
Published: October 2022

Abstract
The nonlinear features of both semiconductor optical amplifiers (SOAs) and semiconductor lasers, which are made from the same InAs/GaAs quantum dot (QD) wafers, are investigated in detail. By employing pump-probe driven four-wave mixing as an experimental tool, the wave conversion process shows notably different profiles for the two types of devices. Due to the contributions of ultrafast, sub-picosecond mechanisms, such as carrier heating and spectral hole burning, the pump-probe frequency can be easily tuned to the THz range. SOAs generally benefit more from sub-picosecond carrier dynamics, hence exhibiting a higher conversion efficiency (CE) in the THz range, compared to their laser diode counterparts. The discrepancy even exceeds 10 dB. In addition, laser experiments yield some differences from the amplifier ones, hence leading to a higher nonlinear CE at small detuning ranges. These results strongly improve our insight into the fundamental nonlinear properties of InAs/GaAs QD material, and contribute to the conception of novel devices for future on-chip applications in all-optical communication networks, such as signal wavelength conversion, mode-locking, and optical frequency comb generation.
Fixed template network and dynamic template network: novel network designs for decoding steady-state visual evoked potentials
Authors: Xiao Xiaolin , Xu Lichao , Yue Jin , Pan Baizhou , Xu Minpeng , Ming Dong 
Published: October 2022

Abstract

Objective. Decomposition methods are efficient to decode steady-state visual evoked potentials (SSVEPs). In recent years, the brain–computer interface community has also been developing deep learning networks for decoding SSVEPs. However, there is no clear evidence that current deep learning models outperform decomposition methods on the SSVEP decoding tasks. Many studies lacked the comparison with state-of-the-art decomposition methods in a fair environment. Approach. This study proposed a novel network design motivated by the works of decomposition methods. Fixed template network (FTN) and dynamic template network (DTN) are two novel networks combining the advantages of fixed templates and subject-specific templates. This study also proposed a data augmentation method for SSVEPs. This study compared the intra-subject classification performance of DTN and FTN with that of state-of-the-art decomposition methods on three public SSVEP datasets. Main results. The results show that both FTN and DTN achieved the suboptimal classification performance compared with state-of-the-art decomposition methods. Significance. Both network designs could enhance the decoding performance of SSVEPs, making them promising networks for improving the practicality of SSVEP-based applications.