bluuebunny/crossref_metadata_2025 huggingface dataset:
Spinal Dural Arteriovenous Fistula, a Rare and Frequently Misdiagnosed Cause of Mielopathy – Case Report and Review of the Literature
Authors: Souza Thiago Magalhães de , Silva Paulo Gabriel Sacramento da , Paula Fellipe de , Ghizoni Enrico , Joaquim Andrei Fernandes
Published: July 2024

Spinal dural arteriovenous fistulas (SDAVFs) are rare vascular malformations with unspecific clinical manifestations, which often lead to misdiagnosis and delay in the establishment of effective therapies. Since the neurological prognosis depends on symptom duration and pretreatment neurological status, rapid identification and obliteration of the fistula are key to provide patients with a better quality of life. We herein describe an illustrative case of an elderly patient presenting with progressive myelopathy, with a definitive diagnosis of SDAVF after 18 months of the initial symptoms. We also review the core concepts regarding this condition and discuss strategies to prevent misdiagnosis and worsening of the neurological outcome.
Multi-doping effect on the martensitic transformation behavior of shape memory alloys
Authors: Yang Yuanchao , Pang Jianbo , Dang Pengfei , Xu Yangyang , Zhang Lei , Zhou Yumei , Ding Xiangdong , Sun Jun , Lookman Turab , Xue Dezhen
Published: July 2024

Incorporating various elements into host shape memory alloys (SMAs) has proven to be an effective strategy for optimizing their functional properties. However, modeling the complex multi-doping effect is challenging. In the present study, we introduced a phenomenological model based on Ginzburg–Landau theory, wherein each doping element is conceptualized as an internal dilatational stress. This internal stress is represented as a spatial Gaussian distribution characterized by two influential parameters: potency (h) and range (σ). The interaction between doping elements arises from the superposition of these stresses. Utilizing a time-dependent Ginzburg–Landau simulation based on our proposed model, diverse combinations of h and σ replicate the varied experimental outcomes associated with multi-doping effects. This model offers insight into the understanding of the doping impact on martensitic transformation and may contribute to the development of SMAs with tailored properties.
Discovery of dissipative microwave photonic soliton molecules in dual-bandpass optoelectronic oscillator
Authors: Tian Huan , Li Junwen , Lyu Weiqiang , Zhang Lingjie , Zeng Zhen , Zhang Yaowen , Zhang Zhiyao , Zhang Shangjian , Li Heping , Liu Yong
Published: July 2024

Optoelectronic oscillators (OEOs), which have attracted extensive studies in the past decades, are high quality-factor optoelectronic feedback loops for generating various ultra-pure microwave signals. In essence, OEOs are also dissipative nonlinear systems with multiple timescale characteristics and abundant nonlinearities, which open the possibilities for exploring localized dissipative solitary waves. In this paper, we demonstrate a new-class temporal dissipative soliton, i.e., dissipative microwave photonic soliton molecule (DMPSM), in a dual-bandpass OEO. Both the numerical simulation and experiment are conducted to reveal the physical mechanism of DMPSM generation and to evaluate the characteristics of the generated DMPSM sequences. Unlike optical soliton molecules in mode-locked lasers, the formation of DMPSMs arises from the combined action of multiple timescale coupling, nonlinear bistability, and time-delayed feedback in the OEO cavity, where the soliton interval and number in a DMPSM can be well-controlled through varying the multiple timescale variables in the OEO cavity, and the repetition frequency of the DMPSMs can be tuned through changing that of the initially injected perturbation signal. Meanwhile, the generated DMPSM sequence performs with high stability and excellent coherence, which shows enormous application potentials in pulse radar detection, dense microwave comb generation, and neuromorphology.
In situ interfacial evaluation of aramid/epoxy composites by interfacial stress transfer characteristics
Authors: Wu Zhicheng , Ma Ruitao , Ai Zhijun , Huan Xianhua , Wang Shujuan , Fan Wei , Zhang Qiaogen
Published: July 2024

Interfacial bonding between aramid fibers and epoxy resin is crucial for the mechanical properties of fiber-reinforced epoxy composites. Interfacial stress transfer between resin and fibers bridges microscopic and macroscopic properties. Using micro-Raman spectroscopy for in situ stress measurement offers insights into interface bonding through assessment of interfacial stress transfer characteristics. This study measures stress distribution on loaded microdroplet sample surfaces, analyzes stress transfer at the interface, and proposes an evaluation method using finite element analysis (FEA). The results show that interfacial stress along the fiber decreases from the droplet’s edge to center, indicating stress transfer between the fiber and matrix, as evidenced by the stress-dependent Raman shift of aramid fiber. The interface modulus (Eif), derived from the FEA model, effectively reflects interface bonding, with droplet shape influence removed in evaluations. The agreement between the proposed method and the transverse fiber bundle test confirms its applicability. The method offers a direct, non-destructive, and shape-independent way to evaluate the interface of aramid/epoxy composites.
Low-energy atomic and molecular hydrogen ion interaction with low-work function electride 12CaO · 7Al2O3
Authors: Yamaoka Hitoshi , Tanaka Nozomi , Nishiwaki Mayuko , Yamada Ippei , Sasao Mamiko , Matsumoto Yoshikatsu , Tsumori Katsuyoshi , Wada Motoi
Published: July 2024

To efficiently generate H− ions from positive atomic or molecular hydrogen beams injected onto a solid surface, it has been suggested to use a material with a low-work function as the target material. However, it is not clear under what conditions the most efficient H− production is realized for incident beam parameters or reflection angles. Therefore, we studied the interaction between low-energy atomic and molecular hydrogen beams (less than 1 keV/nucleon) with a low-work function electride 12CaO⋅7Al2O3 (C12A7). The production ratio of H− to H+ ions from the C12A7 electride was much higher than Mo targets with higher work functions, especially at smaller incident and smaller reflection angles. The H− to H+ production ratio slightly increased as the incident energies were decreased, but there was no significant difference between the electride and Mo targets. These results indicate that smaller incident angles and lower beam energies of the incident hydrogen beam are favorable for the enhancement of the production ratio of H− to H+ ions in C12A7. The higher production ratio appeared at the vertical beam energies less than on the order of 100 eV, where quantum mechanical processes may become important.
Experimental study on the penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow
Authors: Zhou Yaozhi , Li Chenyang , Li Qinglian , Cai Zun , Chen Zihang , Sun Mingbo
Published: July 2024

The penetration and evaporation characteristics of a liquid kerosene jet in the supersonic crossflow were experimentally investigated in this study. The experiments were carried out in both cold and high-enthalpy inflows. Detailed spray images were obtained using planar laser scattering techniques. The structures of the spray field were further analyzed on the basis of high spatial and temporal resolution images. The results show that the atomization and evaporation characteristics of a liquid kerosene jet are related to the crossflow temperature, liquid–gas momentum flux ratio, and injection distance. It is found that the breakup process of a liquid jet is accelerated in the high-enthalpy inflow. To accurately describe the maximum flow distance along the direction that kerosene can reach in the state of droplets, the survival distance is defined. It is revealed that the penetration depth and survival distance of the liquid kerosene jet decrease clearly with increase in the crossflow temperature. For the cavity-based combustor, the liquid kerosene jet can mix more sufficiently in the cavity region by reducing the injection distance and liquid–gas momentum flux ratio.
Improvement of energy performance of a two-way pumping station based on controllable diffusion technology
Authors: Zheng Yunhao , Li Yanjun , Yuan Shouqi , Zhu Xingye , Wang Mengcheng
Published: July 2024

Energy performance is a crucial parameter for evaluating a two-way pumping station. However, the sharp decrease in efficiency within overload flow rates presents a challenge. To address this issue, the controllable diffusion technology (CDT) is developed based on asymmetric inflow theory. Transient numerical simulation is carried out under five different distortion angles. The energy performance and entropy production dissipation before and after the application of CDT are comprehensively studied. (a) First, CDT successfully improves the operation efficiency within the overload flow rate range. The reverse distortion has a better improvement effect than the syntropic distortion. (b) Second, under asymmetric inflow conditions, the reduction in the axial velocity causes the best-efficiency point to deviate toward the overload flow rate. This leads to an increase in the total entropy production (TEP) within 0.7Qdes–0.95Qdes, followed by a decrease within 1.05Qdes–1.3Qdes. (c) Third, the CDT-induced horizontal velocity causes a mismatch between the impeller inflow angle and blade placement angle, which leads to uneven spatial distribution of the total entropy production rate inside the pumping station.
Optimizing porous medium electrode suspension drying: A numerical simulation
Authors: Ye Xin , Yang Zhiming , Liu Xijiang , Lu Qian , Yuan Shuai , Jiang Fengze
Published: July 2024

The drying process of porous medium electrodes is crucial for optimizing the performance of lithium-ion batteries. Among various drying methods, convection drying has been proven to be an effective double-sided and contactless technique for these electrodes, enhancing manufacturing quality and efficiency. This study investigates the impact of different drying parameters on the drying process of porous medium electrodes by establishing a coupling model for convective drying. The particle swarm algorithm optimized the drying parameters to minimizing drying time and energy consumption. As a result of this optimization, the optimal drying temperature and Reynolds number were found to be 104.77 °C and 3082.55, respectively. Furthermore, implementing a multi-stage drying process effectively prevents internal binder migration within the porous medium and ensures even distribution of components, thereby enhancing electrode performance. This study examines the effects of different multi-stage drying schemes on the drying time and energy consumption of porous medium electrodes based on the optimal drying parameters. The optimal multi-stage drying scheme, characterized by temperature profiles of 104.77 (0–15 s) − 90 (15–44 s) − 104.77 (>44 s) °C, was proposed to achieve both reduced drying time and low energy consumption. With this scheme, the drying process of porous medium electrodes achieved a suitable drying time of 137.50 s and a low energy consumption of 285 110.09 kJ/m3. The proposed model explores the drying process and provides valuable theoretical guidance for establishing appropriate drying parameters in the actual production of lithium-ion battery electrodes.
Unsteady solute dispersion of electro-osmotic flow of micropolar fluid in a rectangular microchannel
Authors: Subudhi Duryodhan , Jangili Srinivas , Barik Swarup
Published: July 2024

This study scrutinizes the two-dimensional concentration distribution for a solute cloud containing a micropolar fluid in a rectangular microchannel under the influence of an applied electric field. The concentration distribution is obtained up to second order approximation using Mei's homogenization method. Analytical formulas are derived for dispersion coefficient, mean and two-dimensional concentration distributions. This study also includes the analytical expressions for electric potential, velocity, and microrotation profiles. This study discusses the impact of coupling number, couple stress parameter, electric double layer thickness, and Péclet number on solute concentration distribution. The results of fluid velocity and dispersion coefficient are validated with available works in the literature. The non-Newtonian parameter and electric double layer thickness are shown to have a significant impact on dispersion. Our study reveals that concentration distribution rises but spreading of solute reduces when the coupling number increases. This is also true when the Debye length decreases. It is also obtained that the solute spreads more in the Newtonian fluid case compared to the micropolar fluid case. Finally, coupling number and electric double layer thickness show a symmetric pattern to the indicator function for the transverse concentration variation rate. The findings of this work have broad implications in deoxyribonucleic acid analysis, chemical mixing, and separation.
A generative adversarial network based on an efficient transformer for high-fidelity flow field reconstruction
Authors: Shen Liming , Deng Liang , Liu Xuliang , Wang Yueqing , Chen Xinhai , Liu Jie
Published: July 2024

The reconstruction of high-fidelity flow fields from low-fidelity data has attracted considerable attention in fluid dynamics but poses many challenges to existing deep learning methods due to the spatiotemporal complexity of flows and the lack of standardized benchmark datasets. In this study, we generate a low- and high-fidelity dataset containing 25 600 snapshots of four representative flow dynamics simulations using eight different numerical-precision and grid-resolution configurations. Using this dataset, we develop a physics-guided transformer-based generative adversarial network (PgTransGAN) for concurrently handling numerical-precision and grid-resolution enhancement. PgTransGAN leverages a dual-discriminator-based generative adversarial network for capturing continuous spatial and temporal dynamics of flows and applies a soft-constraint approach to enforce physical consistency in the reconstructed data using gradient information. An efficient transformer model is also developed to obtain the long-term temporal dependencies and further alleviate storage constraints. We compare the performance of PgTransGAN against standard linear interpolation and solutions based solely on convolutional neural networks or generative adversarial networks, and demonstrate that our method achieves better reconstruction quality at the data, image, and physics levels with an upscaling factor of 4 or even 8 in each grid dimension.
Shear-induced phase behavior of bidisperse jammed suspensions of soft particles
Authors: Alrashdan Rakan , Yankah Harry Kojo , Cloître Michel , Khabaz Fardin
Published: July 2024

Particle dynamics simulations are used to determine the shear-induced microstructure and rheology of jammed suspensions of soft particles. These suspensions, known as soft particle glasses (SPGs), have an amorphous structure at rest but transform into ordered phases in strong shear flow when the particle size distribution is relatively monodisperse. Here, a series of bidisperse SPGs with different particle radii and number density ratios are considered, and their shear-induced phase diagrams are correlated with the macroscopic rheology at different shear rates and volume fractions. These shear-induced phase diagrams reveal that a combination of these parameters can lead to the emergence of various microstructures such as amorphous, layered, crystals, and in some cases, coexistence of amorphous and ordered phases. The evolution of the shear stress is correlated with the change in the microstructure and is a shear-activated process. Stress shows pseudo-steady behavior during an induction period before the final microstructural change leading to the formation of ordered structures. The outcomes provide a promising method to control the phase behavior of soft suspensions and build new self-assembled microstructures.
Study on the liquid metal flow transitions behind a circular cylinder under the axial magnetic field
Authors: Zhang Xiang-Fei , Lyu Ze , Yang Juan-Cheng , Zhang Nian-Mei , Kolesnikov Yurii , Ni Ming-Jiu
Published: July 2024

We study the magnetohydrodynamic flow around a circular cylinder confined in a rectangular duct. In this configuration, both the circular cylinder and the walls of the rectangular duct are electrically insulating, while the magnetic field aligns with the axial direction of the cylinder. The experimental measurements are performed by controlling two parameters Re and N (N is the ratio of electromagnetic forces to inertial forces) in the ranges of (180–722) and (0.8–264), respectively. Utilizing the electrical potential method, we employ both movable and wall probes to obtain the local flow velocities in the wake of the cylinder. By analyzing the space correlation of the signals obtained from the wall probes, a distinct transition in the flow behavior is observed, transitioning from a three-dimensional state to a quasi-two-dimensional (Q2D) state when the external magnetic field reaches a sufficient strength (N > 3). Additionally, the Q2D state allows for a further subdivision based on the scaling relationship Re/Ha∼(0.41–0.42) in the stability map, thereby distinguishing between steady and unsteady flow states, which is consistent with findings from previous studies.
Quantum decoherence dynamics in stochastically fluctuating environments
Authors: Cai Xiangji , Feng Yanyan , Ren Jing , Peng Yonggang , Zheng Yujun
Published: July 2024

We theoretically study the decoherence of a two-level quantum system coupled to noisy environments exhibiting linear and quadratic fluctuations within the framework of a stochastic Liouville equation. It is shown that the intrinsic energy levels of the quantum system renormalize under either the linear or quadratic influence of the environmental noise. In the case of quadratic dependence, the renormalization of the energy levels of the system emerges even if the environmental noise exhibits stationary statistical properties. This is in contrast to the case under linear influence, where the intrinsic energy levels of the system renormalize only if the environmental noise displays nonstationary statistics. We derive the analytical expressions of the decoherence function in the cases where the fluctuation of the frequency difference depends linearly and quadratically on the nonstationary Ornstein–Uhlenbeck noise (OUN) and random telegraph noise (RTN) processes, respectively. In the case of the linear dependence of the OUN, the environmental nonstationary statistical property can enhance the dynamical decoherence. However, the nonstationary statistics of the environmental noise can suppress the quantum decoherence in this case under the quadratic influence of the OUN. In the presence of the RTN, the quadratic influence of the environmental noise does not give rise to decoherence but only causes a determinate frequency renormalization in dynamical evolution. The environmental nonstationary statistical property can suppress the quantum decoherence of the case under the linear influence of the RTN.
Surrogate multi-objective optimization of missile RCS performance in hypersonic rarefied flow of the near space
Authors: Zhou Kaijun , Lou Yongchun , Zhang Songqin , Ding Dongming , Zhang Bin
Published: July 2024

This study focuses on optimizing the lateral jet efficiency of THAAD-like (Terminal High Altitude Area Defense) missiles operating under hypersonic rarefied flow conditions. We employ the DSMC-QK algorithm to simulate the three-dimensional lateral jet flow field, accounting for thermochemical non-equilibrium effects. The analysis investigates how the force/momentum amplification coefficient varies with the angle of attack, jet pressure ratio, jet Mach number, and jet gas composition. Subsequently, we develop an artificial neural network (ANN) proxy model using the pyrenn toolbox, achieving an average prediction error of 0.866% and a maximum error of 1.60%. Utilizing this ANN model, we perform single- and multi-objective optimizations with a genetic algorithm to determine the optimal jet parameters. The results reveal that in multi-objective optimization, the proportion of helium in the jet gas composition increases, leading to a slight reduction in the force amplification coefficient but a substantial 61.4% decrease in the mass flow rate. This demonstrates that a judicious selection of jet gas composition can significantly reduce mass flow while maintaining high jet efficiency, thus achieving efficient lateral jet control.
Design and mathematical modeling of an amphibious quadcopter for versatile operations
Authors: Hosur Santosh , Chikkanna N. , Buradi Abdulrajak , Barik Debabrata , Paramasivam Prabhu , Medhi Bhaskar Jyoti , Bora Bhaskor Jyoti
Published: July 2024

Amphibious drone is an Unmanned Aerial Vehicle (UAV) capable of performing in both air and under water for application in various fields, such as marine, military, and underwater habitat research, but complexity in the design and provable mathematical model to withstand the arguably swift changes in the forces during the transition phase makes it difficult to build a sustainable UAV that can operate seamlessly in both media. Beginning with the mathematical principles and physical laws, the basic concept of operation is arrived at in the present study for both media (air and water) keeping the prime objective as developing a reliable drone design and mathematical model that will satisfactorily describe the behavior of the amphibious drone with accuracy by defining the coordinate system to describe the amphibious drone’s kinematics. Basic forces and torques are considered to explicitly describe the drone dynamics using Newton–Euler equations, and the final equation derived is the matrix Newton’s second law. Based on the mathematical model, the final design of the drone is arrived at considering the feasibility of withstanding forces, placement of commercial-off-the-shelf components, and the amount of thrust required to carry the seamless operation. A prototype is built with active buoyancy control technique to control the underwater depth of the drone, which clearly satisfies the design and mathematical model developed in this study.
Flexible oviposition behavior enabled the evolution of terrestrial reproduction
Authors: Touchon Justin C. , McMillan W. Owen , Ibáñez Roberto , Lessios Harilaos A.
Published: July 2024

Among vertebrates, nearly all oviparous animals are considered to have either obligate aquatic or terrestrial oviposition, with eggs that are specialized for developing in those environments. The terrestrial environment has considerably more oxygen but is dry and thus presents both opportunities and challenges for developing embryos, particularly those adapted for aquatic development. Here, we present evidence from field experiments examining egg-laying behavior, egg size, and egg jelly function of 13 species of Central and South American treefrogs in the genus
Dendropsophus,
which demonstrates that flexible oviposition (individuals laying eggs both in and out of water) and eggs capable of both aquatic and terrestrial development are the likely factors which enable the transition from aquatic to terrestrial reproduction. Nearly half of the species we studied had previously undescribed degrees of flexible oviposition. Species with obligate terrestrial reproduction have larger eggs than species with aquatic reproduction, and species with flexible reproduction have eggs of intermediate sizes. Obligate terrestrial breeding frogs also have egg masses that absorb water more quickly than those with flexible oviposition. We also examined eight populations of a single species,
Dendropsophus ebraccatus
, and document substantial intraspecific variation in terrestrial oviposition; populations in rainy, stable climates lay fewer eggs in water than those in drier areas. However, no differences in egg size were found, supporting the idea that the behavioral component of oviposition evolves before other adaptations associated with obligate terrestrial reproduction. Collectively, these data demonstrate the key role that behavior can have in facilitating major evolutionary transitions.
Transport coefficient approach for characterizing nonequilibrium dynamics in soft matter
Authors: He HongRui , Liang Heyi , Chu Miaoqi , Jiang Zhang , de Pablo Juan J. , Tirrell Matthew V. , Narayanan Suresh , Chen Wei
Published: July 2024

Nonequilibrium states in soft condensed matter require a systematic approach to characterize and model materials, enhancing predictability and applications. Among the tools, X-ray photon correlation spectroscopy (XPCS) provides exceptional temporal and spatial resolution to extract dynamic insight into the properties of the material. However, existing models might overlook intricate details. We introduce an approach for extracting the transport coefficient, denoted as

J
(
t
)

, from the XPCS studies. This coefficient is a fundamental parameter in nonequilibrium statistical mechanics and is crucial for characterizing transport processes within a system. Our method unifies the Green–Kubo formulas associated with various transport coefficients, including gradient flows, particle–particle interactions, friction matrices, and continuous noise. We achieve this by integrating the collective influence of random and systematic forces acting on the particles within the framework of a Markov chain. We initially validated this method using molecular dynamics simulations of a system subjected to changes in temperatures over time. Subsequently, we conducted further verification using experimental systems reported in the literature and known for their complex nonequilibrium characteristics. The results, including the derived

J
(
t
)

and other relevant physical parameters, align with the previous observations and reveal detailed dynamical information in nonequilibrium states. This approach represents an advancement in XPCS analysis, addressing the growing demand to extract intricate nonequilibrium dynamics. Further, the methods presented are agnostic to the nature of the material system and can be potentially expanded to hard condensed matter systems.
The CH1 domain influences the expression and antigen sensing of the HIV-specific CH31 IgM-BCR and IgG-BCR
Authors: Ortiz Yaneth , Anasti Kara , Kane Advaiti Pai , Cronin Kenneth , Alam S. Munir , Reth Michael
Published: July 2024

How different classes of the B cell antigen receptor (BCR) sense viral antigens used in vaccination protocols is poorly understood. Here, we study antigen binding and sensing of human Ramos B cells expressing a BCR of either the IgM or IgG1 class with specificity for the CD4-binding-site of the envelope (Env) protein of the HIV-1. Both BCRs carry an identical antigen binding site derived from the broad neutralizing antibody (bnAb) CH31. We find a five times higher expression of the IgG1-BCR in comparison to the IgM-BCR on the surface of transfected Ramos B cells. The two BCR classes also differ from each other in their interaction with cognate HIV Env antigens in that the IgG1-BCR and IgM-BCR bind preferentially to polyvalent and monovalent antigens, respectively. By generating an IgM/IgG1 chimeric BCR, we found that the class-specific BCR expression and antigen-sensing behavior can be transferred with the CH1γ domain from the IgG1-BCR to the IgM-BCR. Thus, the class of CH1 domain has an impact on BCR assembly and expression as well as on antigen sensing.
Impact of molecular convection in time-resolved thermal lensing: a computational exploration
Authors: Sharma Aman , Goswami Debabrata
Published: July 2024

In this study, we comprehensively investigate thermal lens (TL) spectroscopy, known for its ultra-sensitivity in probing molecular properties through nonlinear heating responses to femtosecond lasers. Using time-resolved TL spectroscopy and numerical simulations, we focus on the influence of convection on heat generation and the resulting phase shift in the probe beam. We examined single-beam, dual-beam same wavelength, and dual-beam different wavelength scenarios, systematically investigating power dependence, pump beam spot size, and sample length limitations. Our findings reveal a direct relationship between the TL effect and pump power, resulting in decreased probe beam transmittance with increasing convection. Additionally, the TL strength grows within the Rayleigh regime as the sample length increases. Utilizing the same wavelength for the probe beam enhances the TL effect in dual-beam setups. Notably, tight focusing of the pump beam substantially reduces the lag between convection and conduction. Our empirical results closely match the experimental data, providing a thorough explanation of the TL process and its underlying principles. These insights can be applied to design and optimize TL-based optical devices and systems for higher sensitivity, highlighting the potential of TL spectroscopy in advanced molecular property probing.
High-resolution defect imaging of composites using delay-sum-and-square beamforming algorithm
Authors: Zhao Junhui , Zhang Haiyan , Zhang Hui , Chen Yiting , Zhu Wenfa , Zhu Qi
Published: July 2024

High-resolution ultrasonic imaging for defects in anisotropic multilayer carbon fiber reinforced polymers (CFRPs) is challenging because of the severe ultrasonic attenuation and the low signal-to-noise ratio (SNR) of echoes. The existing delay-multiply-and-sum (DMAS) beamforming outperforms delay-and-sum (DAS) beamforming in resolution, but with high computational complexity and energy loss. This paper presents a novel delay-sum-and-square (DSAS) beamforming algorithm. It takes full advantage of spatial coherence of captured data in the receiving and transmitting apertures. The incoherent components caused by background noise are suppressed during the imaging. The back-wall reflection method (BRM) is used to correct the direction-dependent velocity. Full-matrix data is experimentally captured and processed on four different CFRP samples. Compared with DAS and DMAS, DSAS has a significant improvement in resolution, SNR and contrast. It demonstrates excellent defect characterization and noise suppression capability with only 17.4% computation time of DMAS.
A novel capacitive sensor interface based on a simple capacitance-to-phase converter
Authors: van Kann Frank J , Veryaskin Alexey V
Published: July 2024

A novel room temperature capacitive sensor interface circuit is proposed and successfully tested, which uses a modified all-pass filter (APF) architecture combined with a simple series resonant tank circuit with a moderate Q-factor. It is fashioned from a discrete inductor with small dissipation resonating with a grounded capacitor acting as the sensing element to obtain a resolution of ΔC ∼ 2 zF in a capacitance range of 10–30 pF. The circuit converts the change in capacitance to the change in the phase of a carrier signal in a frequency range with a central frequency set up by the tank circuit’s resonant frequency and is configured to act as a close approximation of the ideal APF. This cancels out the effects of amplitude modulation when the carrier signal is imperfectly tuned to the resonance. The proposed capacitive sensor interface has been specifically developed for use as a front-end constituent in ultra-precision mechanical displacement measurement systems, such as accelerometers, seismometers, gravimeters and gravity gradiometers, where moving plate grounded air gap capacitors are frequently used. Some other applications of the proposed circuit are possible including the measurement of the electric field, where the sensing capacitor depends on the applied electric field, and cost effective capacitive gas sensors. In addition, the circuit can be easily adapted to function with very small capacitance values (1–2 pF) as is typical in MEMS-based transducers.
Dynamic chaos unveiled: enhancing ship’s attitude time series prediction through spatiotemporal embedding and improved transformer model
Authors: Zhao Huachuan , Wang Zicheng , Wang Guochen , Yu Fei
Published: July 2024

During ship operations at sea, the vessel’s attitude undergoes continuous changes due to various factors such as wind, waves, and its own motion. These influences are challenging to mathematically describe, and the changes in attitude are also influenced by multiple interconnected factors. Consequently, accurately predicting the ship’s attitude presents significant challenges. Previous studies have demonstrated that phenomena like wind speed and wave patterns exhibit chaotic characteristics when affecting attitude changes. However, research on predicting ship attitudes lacks an exploration of whether chaotic characteristics exist and how they can be described and applied. This paper initially identifies the chaotic characteristics of ship attitude data through phase space reconstruction analysis and provides mathematical representations for them. Based on these identified chaotic characteristics, a Transformer model incorporating feature embedding layers is employed for time series prediction. Finally, a comparison with traditional methods validates the superiority of our proposed approach.
Necessary and sufficient conditions for Kolmogorov’s flux laws on

T

2

and

T

3
Authors: Dudley Ethan
Published: July 2024

Necessary and sufficient conditions for the third order Kolmogorov universal scaling flux laws are derived for the stochastically forced incompressible Navier Stokes equations on the torus in 2D and 3D. This paper rigorously generalises the result of (Bedrossian 2019 Commun. Math. Phys.
367 1045–75) to functions which are heavy-tailed in Fourier space or have local finite time singularities in the inviscid limit. In other words, we have rigorously derived the existence of the well known physical relationships, the direct and inverse cascades. Furthermore we show that the rate of the direct cascade is proportional to the amount of energy ‘escaping to infinity’ in spectral space as well as a measure of the total singularities within the solution. Similarly, an inverse cascade is proportional to the amount of energy that moves towards the k = 0 Fourier mode in the invisicid limit.
The exact solutions for the fractional Riemann wave equation in quantum mechanics and optics
Authors: Mohammed Wael W , Cesarano Clemente , Iqbal Naveed , Sidaoui Rabeb , Ali Ekram E
Published: July 2024

In this paper, the fractional Riemann wave equation with M-truncated derivative (FRWE-MTD) is considered. The Jacobi elliptic function method and the modified extended tanh function method are applied to acquire new elliptic, rational, hyperbolic, and trigonometric functions solutions. Moreover, we expand some earlier studies. The obtained solutions are important in explaining some exciting physical phenomena, since the Riemann wave equation is used in various fields, including quantum mechanics, optics, signal processing, and general relativity. Also, this equation is used to describe the propagation of waves in various dispersive systems, where wave motion is affected by the medium through which it travels. Several 3D and 2D graphs are shown to demonstrate how the M-truncated derivative affects the exact solutions of the FRWE-MTD.
Design of a discrete memristive chaotic map: fractional-order memory, dynamics and application
Authors: Wang Huihai , Xin Zuyi , He Shaobo , Sun Kehui
Published: July 2024

In this paper, a discrete fracmemristor (DFM) model is derived based on the Caputo difference, and a new fractional-order chaotic map is designed. Dynamics of the proposed map is investigated in detail by means of Lyapunov exponent spectra, bifurcation diagrams, PE complexity and multistability analyses. Compared with the coupled discrete integer-order memristor (DIM), the map coupled with the DFM products richer dynamics, including larger attractor distribution, fewer numerically periodic windows, and higher complexity. Besides, the order becomes additional bifurcation parameter. Finally, the proposed map is implemented on Field-Programmable Gate Array (FPGA) platform, and applied in a pseudorandom number generator (PRNG), which further demonstrates its application value.
The Symbiotic X-Ray Binary IGR J16194-2810: A Window on the Future Evolution of Wide Neutron Star Binaries From Gaia
Authors: Nagarajan Pranav , El-Badry Kareem , Lam Casey , Reggiani Henrique
Published: July 2024

We present optical follow-up of IGR J16194-2810, a hard X-ray source discovered by the INTEGRAL mission. The optical counterpart is a ∼500 L
⊙ red giant at a distance of 2.1 kpc. We measured 17 radial velocities (RVs) of the giant over a period of 271 days. Fitting these RVs with a Keplerian model, we find an orbital period of P
orb = 192.73 ± 0.01 days and a companion mass function f(M
2) = 0.365 ± 0.003 M
⊙. We detect ellipsoidal variability with the same period in optical light curves from the ASAS-SN survey. Joint fitting of the RVs, light curves, and the broadband spectral energy distribution allows us to robustly constrain the masses of both components. We find a giant mass of

M

⋆

=

0.99

−
0.03

+
0.02

M

⊙

and a companion mass of

M

2

=

1.23

−
0.03

+
0.05

M

⊙

, implying that the companion is a neutron star (NS). We recover a 4.06 hr period in the system’s TESS light curve, which we tentatively associate with the NS spin period. The giant does not yet fill its Roche lobe, suggesting that current mass transfer is primarily via winds. Modules for Experiments in Stellar Astrophysics evolutionary models predict that the giant will overflow its Roche lobe in 5–10 Myr, eventually forming a recycled pulsar + white dwarf binary with a ∼900 days period. IGR J16194-2810 provides a window on the future evolution of wide NS + main sequence binaries recently discovered via Gaia astrometry. As with those systems, the binary’s formation history is uncertain. Before the formation of the NS, it likely survived a common envelope episode with a donor-to-accretor mass ratio ≳10 and emerged in a wide orbit. The NS likely formed with a weak kick (v
kick ≲ 50 km s−1), as stronger kicks would have disrupted the orbit.
Investigating the level structure of 206Rn: evolution from seniority regime to collective dynamics*
Authors: Guo 郭 Rui 瑞 , Zhu 竺 Li-Hua 礼华 , Lu 陆 Jing-Bin 景彬 , Fu 傅 Guan-Jian 冠健 , Wang 王 Meng 萌 , Sun 孙 Bao-Hua 保华 , Zhang 张 Gao-Long 高龙 , Ren 任 Zhen 臻 , Wu 吴 Yi-Heng 义恒 , Zheng 郑 Yun 云 , He 贺 Chuang-Ye 创业 , Wang 汪 Jin-Long 金龙 , Wu 吴 Xiao-Guang 晓光 , Yao 姚 Shun-He 顺和
Published: July 2024

Excited states of

have been examined via the

(

, 5n)

fusion reaction at a beam energy of 78 MeV. A number of transitions and levels are identified by the γ-γ coincidence measurement, further enriching the level scheme of

. The full configuration shell model and nucleon-pair approximation (NPA) were utilized to investigate the single-particle configurations and seniority structures in

. The results of these two calculations suggest that

and

states exhibit only a 50% component of a seniority-two state associated with a broken neutron pair. The collectivity of these two states primarily arises from configuration mixing due to residual proton-neutron interactions. Furthermore,

and

states are predominantly characterized by a seniority-two state marked by a broken proton pair.
Effects of torsion charge on optical appearance and additional photon rings of an asymmetric thin-shell wormhole
Authors: Jing 景 Qi-Qin 琪钦 , He 何 Ke-Jian 柯腱 , Luo 罗 Zhi 智
Published: July 2024

In this paper, we study the optical properties of asymmetric thin-shell wormholes (ATWs) under torsion charge. Utilizing the cut-and-paste method developed by Visser, we construct these wormholes and determine their key physical properties, such as the radius of the photon sphere and critical impact parameters, under different torsion charges. Furthermore, we investigate the effective potential and behavior of photon motion within the wormhole spacetime, identifying a relationship between photon trajectories and impact parameters. The study focuses on scenarios where thin accretion disks act as the primary light source. It reveals that the optical features of ATWs under torsion charge significantly differ from those of black holes (BHs). Notably, an increase in torsion charge leads to a reduction in the sizes of both extra photon rings and lensing bands, which serve as important markers for distinguishing and characterizing ATW spacetimes from those of BHs.
Heat currents in qubit systems
Authors: Fogedby Hans C
Published: July 2024

There is a current interest in quantum thermodynamics in the context of open quantum systems. An important issue is the consistency of quantum thermodynamics, in particular the second law of thermodynamics, i.e. the flow of heat from a hot reservoir to a cold reservoir. Here recent emphasis has been on composite system and in particular the issue regarding the application of local or global master equations. In order to contribute to this discussion we discuss two cases, namely as an example a single qubit and as a simple composite system two coupled qubits driven by two heat reservoirs at different temperatures, respectively. Applying a global Lindblad master equation approach we present explicit expressions for the heat currents in agreement with the second law of thermodynamics. The analysis is carried out in the Born–Markov approximation. We also discuss issues regarding the possible presence of coherences in the steady state.
Effect of different forms of calcium sulfate on the properties of cement
Authors: Staněk T , Szklorzová H , Kubátová D , Rybová A
Published: July 2024

In our conditions, mainly flue gas desulfurization gypsum (FGD gypsum) is used as a cement setting regulator. When cement is ground, it decomposes into hemihydrate or even anhydrite as the temperature rises. The ground cement is placed in a storage silo where the increased temperature is compounded by increased pressure and the cement properties are affected by the moisture released and by the change in the phase composition of the setting regulator. Under laboratory conditions, hemihydrate and anhydrite II and III were prepared from one type of FGD gypsum. Their purity was monitored by X-ray diffraction analysis and differential thermal analysis. The prepared calcium sulfates were used in different proportions as setting regulators in the laboratory preparation of Portland cements. Technological properties such as strength and solidification were then determined for cements. The hydration process was monitored by the calorimetric method.
Effect of thermo-oxidative ageing on changes of physical-mechanical parameters of aramid and UHMWPE laminates
Authors: Beránková Irena , Mikulíková Regina , Křest’an Jan
Published: July 2024

This work is focused on monitoring of the effect of thermo-oxidative ageing of laminates on their physical-mechanical parameters, such as tensile strength, tensile modulus of elasticity, flexural strength, flexural modulus of elasticity and hardness. Changes of mentioned parameters were observed on two types of laminates based on aramid and two types based on UHMWPE (Ultra High Molecular Weight Polyethylene). The laminates were exposed to the accelerated thermo-oxidative ageing under higher temperature in the presence of atmospheric oxygen. The aim of the work was to find the physical-mechanical parameter with the greatest changes caused by thermo-oxidative ageing. This parameter was consequently chosen for the prediction of laminates lifetime. From the obtained results, it can be seen that aramid laminates show a significantly higher temperature resistance compared to UHWPE-based laminates.
Impedance Spectroscopy – comparison of experimental ceramic results with model parameters
Authors: Kusak I , Lunak M , Dvorak R , Nekorancova A , Mizerova C , Rovnanik P
Published: July 2024

Impedance spectroscopy is a non-destructive test method belonging to the group of electrical engineering measurements. The method is suitable for monitoring the quality of building materials even with low conductivity. Although the method focuses on the intrinsic conductivity of systems, most IS techniques, including data analysis methods, conceive of the material in terms of a lossy dielectric. In selecting the material for testing with the IS method, an attempt was made to bring the IS capabilities as close as possible to practical, real-world materials. This paper is devoted to a comparison of the impedance characteristics of ceramics with three types of dielectric models that are described in theory or referenced in the literature. The ceramic samples were fabricated using different material additions, such as bentonite, phosphoric acid, or sodium water glass. Experimental curves of the loss factor versus frequency for all samples are described and then approximations of selected samples are shown successively for all three models considered. Experimental results were obtained from more than 50 points in each characterization. Measurements were performed for frequencies from 40 Hz to 1 MHz.
Examples of dynamic test procedures for steel fibre reinforced concrete
Authors: Šperl M , Gajdoš L’ , Drdlová M , Řídký R
Published: July 2024

The aim of this work is to present some examples of experimental tests, which can be usefull for characterizing the resistance to failure of special steel fibre reinforced concrete – SFRC, intended especially for security use in the framework of ballistic and explosion protection. The first type of the tests was the strain gauge - based characterization of the dynamic response of the SFRC concrete block under ballistic loading. The tests were aimed at measuring the deformation response of a concrete specimen of 500 x 500 x 105 mm in dimensions upon the impact of a projectile. The tests were used to support the development and verification of numerical simulation models. For numerical simulations 3D models of individual projectiles were developed. Four T-type strain gauges were glued according to the geometric scheme on the opposite side of a specimen, i.e. on the side behind the impact of the projectile, and they measured the deflection of the plate after the impact of the projectile. The strain response records obtained from the strain gauges were subsequently used for numerical analyses by the use of the LS-DYNA software. The average maximum deflection of the plate at the impact of the projectile was characterized by the strain 400 µm/m. The second type of the tests was concerned with the method of measuring the quasi-dynamic tensile strength of special concrete specimens using an instrumented Charpy tester. The results compare both the breaking energy and the maximum force achieved for hobby concrete (HB) and hobby concrete with wires (HBD) specimens. These were pilot tests to develop the most suitable testing method. For the HB and HBD specimens the maximum force in the tests was found to be 55 N vs. 600 N, and the breaking energy to be 0.4 J vs. 1.3 J.