bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical simulation study of liquid–liquid mixing of high-viscosity fluids under laminar flow in a reverse flow multi-stage Tesla valve
Authors: Zhou Yunxin , Shen Rui , Tang Hao , Xu Jianxin , Yin Wuliang , Zhang Zhentao , Wang Hua
Published: September 2024

In this study, computational fluid dynamics was employed to conduct a numerical simulation of the mixing performance and flow characteristics of two highly viscous liquids under laminar flow conditions within a reversed Tesla valve. Scalar transport techniques are employed to analyze the efficiency of liquid–liquid mixing in high-viscosity fluids. The focus of this study is to investigate the optimal mixing behavior between different parameters. Results indicate that an increase in Reynolds number leads to intensified Dean vortices, thereby promoting liquid–liquid mixing efficiency. Additionally, the mixing coefficient shows a negative correlation with Schmidt number (Sc), with a diminishing impact on the mixing coefficient when Sc ≥ 104. This is attributed to the dominance of fluid flow in controlling mixing within the channel at higher Schmidt numbers. Furthermore, this study compares the influence of valve angles (α) and stage numbers (n) on the mixing coefficient under identical Reynolds and Schmidt number conditions. As the number of Tesla valve stages increases, fluid acceleration within the pipeline is enhanced. Moreover, larger valve angles result in increased lengths of the curved section, leading to higher mixing efficiency. Therefore, to enhance mixing efficiency, it is recommended to increase the valve angle and the number of stages in the Tesla valve.
The role of the dynamic pressure in the behavior of an oscillating gas bubble
Authors: Brini F. , Seccia L.
Published: September 2024

The paper contains a preliminary study on the role that dynamic pressure might play in the dynamics of a gas bubble oscillating in a liquid. To this aim, we introduce a mathematical model, proposed under the homobaricity hypothesis and deduced from the 14-moment theory of rational extended thermodynamics through significant simplifications, that makes the equations easily integrable over long time intervals. In the presence of a gas with high bulk viscosity, relevant effects can be observed in different physical conditions: isothermal or adiabatic regimes, small amplitude oscillations, non-linear oscillations, resonances, and sonoluminescence. To make the study more realistic, we always refer to carbon dioxide gas, which on the one hand could present high values of bulk viscosity and on the other hand is known for its peculiar behaviors in the framework of cavitation and gas bubbles.
Exponential stability and fixed-time control of a stochastic avian influenza model with spatial diffusion and nonlocal delay
Authors: Yang Shuangyan , Zhang Qimin
Published: September 2024

Spatial heterogeneity, random disturbances in the external environment, and the incubation period of infected individuals collectively have a significant impact on the outbreak of avian influenza. In this paper, a stochastic susceptible-infective-susceptible-infected-recovered (SI-SIR) avian influenza model is established that incorporates spatial diffusion and nonlocal delay. The existence and uniqueness of mild solutions are established by applying the Banach fixed point theorem, the truncation method, and the semigroup approach. Based on the Borel–Cantelli lemma, the mean-square exponential stability and almost sure exponential stability of the mild solution are analyzed. Additionally, in combination with the Lyapunov theory, a fixed-time control strategy is proposed to achieve stability within the desired settling time. Numerical simulations are conducted to validate the impacts of key parameters and enhance the understanding of the results of the theory.
Non-Markovian quantum mechanics on comb
Authors: Iomin Alexander
Published: September 2024

Quantum dynamics of a particle on a two-dimensional comb structure is considered. This dynamics of a Hamiltonian system with a topologically constrained geometry leads to the non-Markovian behavior. In the framework of a rigorous analytical consideration, it is shown how a fractional time derivative appears for the relevant description of this non-Markovian quantum mechanics in the framework of fractional time Schrödinger equations. Analytical solutions for the Green functions are obtained for both conservative and periodically driven in time Hamiltonian systems.
Dynamics of measurement-induced state transitions in superconducting qubits
Authors: Hirasaki Yuta , Daimon Shunsuke , Kanazawa Naoki , Itoko Toshinari , Tokunari Masao , Saitoh Eiji
Published: September 2024

We have investigated temporal fluctuation of superconducting qubits via the time-resolved measurement for an IBM Quantum system. We found that the qubit error rate abruptly changes during specific time intervals. Each high error state persists for several tens of seconds and exhibits an on-off behavior. The observed temporal instability can be attributed to qubit transitions induced by a measurement stimulus. Resonant transition between fluctuating dressed states of the qubits coupled with high-frequency resonators can be responsible for the error-rate change.
Extended perturbative approach including Redfield and Förster limits for qualitative analysis of exciton dynamics in any photosynthetic light harvesting and reaction center
Authors: Kimura Akihiro
Published: September 2024

According to many reports, the various structures of photosynthetic light-harvesting/reaction-center complexes and their molecular-dynamics simulations necessitate a numerically efficient and quality-conserved theory of excitation energy transfer and exciton relaxation in large pigment systems. Although exciton dynamics depend on various parameters, such as exciton coupling strength, exciton–phonon coupling, site energy values for each pigment, and temperature, classifying the transition mechanism for any Hamiltonian into perturbatively delocalized or localized theories is challenging. In this study, perturbative quantum master equations of a reduced density matrix for any orthogonal transformation similar to the coherent modified Redfield theory are derived. Our approach qualitatively conserves the dynamics of relevant perturbative approximations in each limiting case. As an application, any orthogonal transformation of a relevant system is optimized using the average of the square of interactions between orthogonal state transitions. The numerical results for two pigment systems are compared with the limiting formalisms of the modified Redfield and Förster theory.
Magnetostriction related to skyrmion-lattice formation in chiral magnet FeGe
Authors: Mito Masaki , Tajiri Takayuki , Kousaka Yusuke , Miyagawa Marina , Koyama Tamami , Akimitsu Jun , Inoue Katsuya
Published: September 2024

The B20 type chiral magnet FeGe exhibits the formation of skyrmion-lattice (SkL) phases in the vicinity of the magnetic ordering temperature. The SkL is a magnetic superlattice composed of vortex-type topological spin objects, and it has experimentally been known that its formation requires the existence of an intermediate (IM) phase between SkL and the paramagnetic (PM) phases. We take interest in how the crystal lattice experiences the formation of these topological spin texture. In this study, we observed the so-called spin–orbit coupling induced magnetostriction related to these topological spin texture formation, in addition to the ac magnetization anomalies. The temperature and magnetic field dependences of the lattice parameter reflected the transformation of phases, such as helimagnetic (HM), SkL, IM, conical (CM), and PM phases. In the PM region, a phase characterized as gaseous skyrmions was detected similarly to the case of the same B20 type MnSi. Furthermore, the HM, CM, and IM phases were also divided into two regions. Thus, the precise phase diagram near Tc was reconstructed from the prospect of the magnetostriction such that we demonstrated that the stabilization of skyrmions needs a finite magnetic field.
Multi-objective optimization design of a sewage pump based on non-dominated sorting genetic algorithm III
Authors: Ren Yun , Mo Xiaofan , Yang Bo , Zheng Shuihua , Yang Youdong
Published: September 2024

Accumulation of sanitary refuse, such as flexible cloth-like structures or the so-called rags, inflows through sewage pumps are prone to tangling, ultimately leading to clogging and wear. To prevent this, the ability of sewage pumps to handle wet wipes, rags, and similar flexible materials is a key feature that must be considered as the pumps are designed. Therefore, this paper proposed a multi-objective optimization strategy based on the fluid–structure interaction simulation, Support Vector Regression (SVR), and non-dominated sorting genetic algorithm III (NSGA-III). First, the values of the optimization objectives were obtained by a Coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) approach. Then, SVR was utilized to establish an approximate model between the design variables and the optimization objectives. The NSGA-III was applied to search the Pareto front. Finally, the improved impeller model was selected by adopting technique for order preference by similarity to an ideal solution (TOPSIS) with entropy weight. The results show that the multi-objective optimization method is suitable for the optimization design of sewage pumps. Comparing the numerical calculations of the original pump and the optimized pump, the results show that the optimized head and efficiency increased by 9.7% and 7.13%, respectively. The optimized pump improves the passage rate of the rag and effectively improves the clogging behavior. The wear amount of the optimized pump is significantly reduced by 32.54%.
Dynamic three-dimensional measurement and analysis of rotating polygons
Authors: Yang Wen , Wang Xiangyu , Martin Witkowski Laurent
Published: September 2024

Rotating polygons are geometric patterns formed spontaneously by the free surface of a rotating fluid driven by a rotating disk at the bottom of a partially filled cylindrical container. Most previous studies mainly predict the number of polygon apexes as a function of disk rotation speed and initial fluid depth. We propose to experimentally characterize this three-dimensional instability by means of highly accurate measurements of the free surface height using Fourier transform profilometry. For a given initial height of 26 mm in a cylindrical cavity of radius 140 mm, these measurements enabled us to not only revisit quantitatively the previous analysis in the fully developed regime but also extend the analysis to the spin-up regime (starting from rest). This latter regime has not been explored. In addition, we describe the mixed-mode regime at the boundary between two clearly established polygons. Thanks to precise space-time resolved surface height measurements, we propose a decomposition of each azimuthal mode that provides valuable information on the growth and dynamics of rotating polygons and can, therefore, serve as a basis for future numerical simulations and theoretical models.
Dynamic local field correction of the one-component plasma
Authors: Kählert Hanno
Published: September 2024

The dynamic local field correction (LFC) of the classical one component plasma is studied with molecular dynamics simulations and analytical theory. Simulation results are obtained for a wide range of frequencies and wavenumbers in the strongly coupled regime. The dynamic LFC generally differs significantly from both the zero and high-frequency limits. The latter is attained at increasingly lower frequencies as the coupling grows. In the long wavelength limit, the frequency dependence of the LFC is studied in detail. Pronounced structure is observed in the vicinity of the plasma frequency and its first harmonic. The results provide access to the plasmon dispersion and are used to test the accuracy of various theoretical approaches. In the low-frequency limit, the simulation data are compared with the predictions of hydrodynamics, which connects the LFC with thermodynamic and transport coefficients. While a direct comparison is typically hindered by the finite size of the simulations, good agreement is found at strong coupling for a relation that connects the imaginary part of the LFC with the viscosity.
Experimentally verified organic electrochemical transistor model
Authors: Bitton Sapir , Alarcon-Espejo Paula , Paterson Alexandra F. , Tessler Nir
Published: September 2024

The Bernards–Malliaras model, published in 2007, is the primary reference for the operation of organic electrochemical transistors (OECTs). It assumes that, as in most transistors, the electronic transport is drift only. However, in other electrochemical devices, such as batteries, the charge neutrality is accompanied by diffusion-only transport. Using detailed 2D device simulations of the entire structure while accounting for ionic and electronic conduction, we show that high ion density (>1019 cm−3) results in Debye screening of the drain–source bias at the electrodes’ interface. Hence, unlike the drift-only current in standard FETs or low ion density OECTs, the current in high ion density OECTs is diffusion only. Also, we show that since in OECTs, the volumetric capacitor and the semiconductor are one, the threshold voltage has a different meaning than that in FETs, where the semiconductor and the gate-oxide capacitor are distinct entities. We use the above insights to derive a new model useful to experimentalists. Lastly, we fabricated PEDOT:PSS fiber-OECTs and used the results to verify the model.
Thermomagnetic pump and thermomagnetic convection in a closed hydrodynamic loop
Authors: Pshenichnikov Alexander F. , Koskov Mikhail A.
Published: September 2024

A thermomagnetic pump is understood as a heated section of a convective loop with a ferrofluid with a non-uniform magnetic field imposed on this section. The part of the heat generated in the pump is transferred by the ferrofluid and absorbed in a cooling radiator, and the other part is dissipated in the environment. The aim of the work is to search for a functional relationship between the velocities of thermomagnetic convection and pump parameters. The problem is solved analytically in the approximation of small Reynolds numbers for a pump containing an electric heater with a circular channel. Equations are obtained that determine the velocity of the convective flow in a parametric form, taking into account the geometry and magnetic field strength and the field dependence of the pyromagnetic coefficient of the ferrofluid. The role of the parameter is played by the spatial decrement of the temperature decay along the contour axis. It is shown that in the case of low Biot numbers the velocity of the flow increases according to the root law with increasing heater power and does not depend on the diameter of the channel. The analytical results are compared with the experimental data for combined (thermomagnetic and gravitational) convection. Neglecting gravitational convection at high heater power leads to an underestimation of the flow velocity by 20–30%. It can be expected that in the case of reduced gravity, the resulting formulas will describe the flow velocity with an accuracy of a coefficient close to unity.
Magnetic domain study in Fe3GaTe2 ferromagnet with strong perpendicular anisotropy using magnetic force microscopy
Authors: Lee Jungsub , Yun Jinyoung , Lee Yeonkyu , Tak Kang Beom , Sung Kim Jun , Haberkorn Nestor , Kim Jeehoon
Published: September 2024

We investigate the magnetic domain behavior of bulk Fe3GaTe2, a van der Waals (vdW) ferromagnet characterized by a Curie temperature (Tc) of 350–380 K and significant perpendicular magnetic anisotropy (PMA). Using magnetic force microscopy, we present the evolution of magnetic domains during cooling from Tc to 300 K, and analyze magnetic domain images along the hysteresis loop at 4.2 K. Our observations reveal a strong temperature-dependent domain structure. From room temperature to Tc, we observe the coexistence of stripe, bubble, and surface spike domains. In contrast, in the zero-field cooled state at 4.2 K, irregular stripe and enclosed ring domains predominate. The correlation between global and local magnetization suggests that the hysteretic behavior in the magnetization results from the rapid nucleation of a few stripe domains evolving into intricate dendritic patterns, a phenomenon not previously observed in other vdW systems. These findings highlight the delicate balance among interlayer exchange coupling, thermal fluctuations, and PMA in the formation of various domains in a 3D vdW system, where shape anisotropy is minimized.
Concurrent processes in the time-resolved solvation and Coulomb ejection of sodium ions in helium nanodroplets
Authors: Calvo Florent
Published: September 2024

Recent pump-probe experiments [Albrechtsen et al., Nature 623, 319 (2023)] have explored the gradual solvation of sodium cations in contact with helium nanodroplets, using a fully solvated xenon atom as a probe exerting a repulsive interaction after its own ionization. In this communication, we computationally examine by means of atomistic ring-polymer molecular dynamics the mechanisms of successive ionizations, shell formation, and Coulomb ejection that all take place within tens of picoseconds and show that their interplay subtly depends on the time delay between the two ionizations but also on the droplet size. The possibility of forming solvated Na+Xe non-covalent complexes under a few tens of picoseconds in such experiments is ruled out based on fragment distributions.
Inhomogeneous stripe phase and tunable Majorana zero modes in Rashba s-wave superconducting systems in the presence of in-plane Zeeman field
Authors: Xie Yue , Chai Rui-Feng , Zhu Xiaoyu , Zha Guo-Qiao
Published: September 2024

Based on the extended Bogoliubov–de Gennes theory, the inhomogeneous stripe order and Majorana bound states are demonstrated in s-wave superconducting systems with Rashba spin–orbit interaction when the in-plane Zeeman field is applied. For a fully open square sample, topological phase transitions can be driven by the Zeeman field, and the stripe phase with spatially oscillating order parameter shows up across a critical field strength. The topological channels arise in this phase, which can be utilized to create and manipulate Majorana zero modes. Interestingly, (quasi-)one-dimensional channels with diminished pairing amplitude can be formed in narrow arms of a square loop, accompanied by the reconstruction of energy spectra of the condensate and the realization of robust Majorana zero-energy states at the ends of channels. The associated evolution of topological phases and the location of Majorana zero modes are highly sensitive to the field direction. Moreover, the effects of the rectangular aspect-ratio and the off-centered hole as well as the surface defects on Majorana end modes are explored in Rashba asymmetric loops. In comparison, the field-dependent evolution processes of low-energy levels behave more complicated because the emergence of confined topological channels can be effectively tuned by the length and width of loop arms as well as the size and position of an introduced small indentation at the outer edge. Rich patterns of Majorana corner-like states are generated for such asymmetric systems. Our theoretical predictions may shed new light on the tunability of Majorana zero modes and provide useful guidance for future experiments and applications.
Effect of molecular structure on membrane diffusion: Triphenylmethanes across Escherichia coli studied by second harmonic light scattering
Authors: Hu Xiao-Hua , Dai Hai-Lung
Published: September 2024

Understanding how the structure of molecules affects their permeability across cell membranes is crucial for many topics in biomedical research, including the development of drugs. In this work, we examine the transport rates of structurally similar triphenylmethane dyes, malachite green (MG) and brilliant green (BG), across the membranes of living Escherichia coli (E. coli) cells and biomimetic liposomes. Using the time-resolved second harmonic light scattering technique, we found that BG passively diffuses across the E. coli cytoplasmic membrane (CM) 3.8 times faster than MG. In addition, BG exhibits a diffusion rate 3.1 times higher than MG across the membranes of liposomes made from E. coli polar lipid extracts. Measurements on these two molecules, alongside previously studied crystal violet (CV), another triphenylmethane molecule, are compared against the set of propensity rules developed by Lipinski and co-workers for assessing the permeability of hydrophobic ion-like drug molecules through biomembranes. It indicates that BG’s increased diffusion rate is due to its higher lipophilicity, with a distribution coefficient 25 times greater than MG. In contrast, CV, despite having similar lipophilicity to MG, shows negligible permeation through the E. coli CM on the observation scale, attributed to its more hydrogen bonding sites and larger polar surface area. Importantly, cell viability tests revealed that BG’s antimicrobial efficacy is ∼2.4 times greater than that of MG, which aligns well with its enhanced diffusion into the E. coli cytosol. These findings offer valuable insights for drug design and development, especially for improving the permeability of poorly permeable drug molecules.
A sensitive assay for measuring whole-blood responses to type I IFNs
Authors: Gervais Adrian , Le Floc’h Corentin , Le Voyer Tom , Bizien Lucy , Bohlen Jonathan , Celmeli Fatih , Al Qureshah Fahd , Masson Cécile , Rosain Jérémie , Chbihi Marwa , Lévy Romain , Castagnoli Riccardo , Rothenbuhler Anya , Jouanguy Emmanuelle , Zhang Qian , Zhang Shen-Ying , Béziat Vivien , Bustamante Jacinta , Puel Anne , Bastard Paul , Casanova Jean-Laurent
Published: September 2024

Human inborn errors of the type I IFN response pathway and auto-Abs neutralizing IFN-α, -β, and/or -ω can underlie severe viral illnesses. We report a simple assay for the detection of both types of condition. We stimulate whole blood from healthy individuals and patients with either inborn errors of type I IFN immunity or auto-Abs against type I IFNs with glycosylated human IFN-α2, -β, or -ω. As controls, we add a monoclonal antibody (mAb) blocking the type I IFN receptors and stimulate blood with IFN-γ (type II IFN). Of the molecules we test, IP-10 (encoded by the interferon-stimulated gene (ISG)
CXCL10
) is the molecule most strongly induced by type I and type II IFNs in the whole blood of healthy donors in an ELISA-like assay. In patients with inherited IFNAR1, IFNAR2, TYK2, or IRF9 deficiency, IP-10 is induced only by IFN-γ, whereas, in those with auto-Abs neutralizing specific type I IFNs, IP-10 is also induced by the type I IFNs not neutralized by the auto-Abs. The measurement of type I and type II IFN-dependent IP-10 induction therefore constitutes a simple procedure for detecting rare inborn errors of the type I IFN response pathway and more common auto-Abs neutralizing type I IFNs.
Male crickets in poor condition engage in less same-sex sexual behavior
Authors: Richardson Jon , Hoversten Isabelle P. , Zuk Marlene
Published: September 2024

Same-sex sexual behavior (SSB) is widespread among animals and is often treated as an evolutionary anomaly or mistake. An alternative view is that SSB occurs because individuals have broader or more permissive “mating filters.” A broader filter means directing courtship toward anything that resembles a potential mate, while a narrower filter means having stricter criteria about when to court. Broader filters help ensure animals do not miss out on mating opportunities. However, it may be advantageous for individuals to narrow their mating filters under some conditions, such as when the costs of courtship increase because courting individuals are in poor condition. We examined whether mating filters, and the expression of SSB, is condition dependent in the Pacific field cricket (Teleogryllus oceanicus). When males were in poor condition (because they were reared on a poor diet), they courted other males less. However, condition did not influence courtship toward females. This finding provides evidence that animals can decrease their expression of SSB by flexibly narrowing their mating filters when in poor condition. Our results demonstrate the benefits of a mating filters approach to studying SSB—rather than being a mistake or an anomaly in need of special explanation, SSB may be better viewed as a consequence of flexible, condition-dependent changes in mating behavior. Such an approach can be applied to other contexts where behavior is directed toward unintended targets. We emphasize that our results, like other studies of SSB in nonhuman animals, tell us nothing about sexual identities in humans.
Investigating the Use of Natural Hydrophobic Deep Eutectic Solvents for Extracting Carotenoids from Food and Food By-products
Authors: Sportiello Lucia
Published: September 2024

In today’s food industry, the demand for sustainable methodologies in producing health-promoting natural products is rising. Traditional extraction techniques are increasingly deemed unreliable due to environmental concerns. To address these challenges, the scientific community has developed
Green Chemistry
, a specialized branch that aims to minimize or eliminate hazardous processes and substances in industrial applications. One promising and eco-friendly alternative emerging from Green Chemistry is the use of NaDESs which are prepared with natural components, generally recognized as safe (GRAS), and offer an environmentally benign option for various industrial processes. They are characterized by their biodegradability, low toxicity, and ability to be tailored for specific applications, making them an ideal choice for green extraction methods. In this context, NaHDESs have shown significant potential as extracting media for bioactive compounds, particularly carotenoids, from food and food by-products. Carotenoids, known for their antioxidant properties and health benefits, are highly sought after in the food and nutraceutical industries. Traditional extraction methods often rely on organic solvents, which pose environmental and health risks. In contrast, NaHDESs offer a safer and more sustainable alternative. This study explores the definition, properties, and applications of NaHDESs, with a particular focus on their use in extracting carotenoids. By examining various food and vegetable by-products, the research aims to evaluate the solvent’s efficiency and effectiveness in this application. The findings could pave the way for eco-friendly extraction techniques in the food industry, aligning with the principles of Green Chemistry and addressing the growing demand for natural and health-promoting products.

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Magnetism Measurements of Two-Dimensional van der Waals Antiferromagnet CrPS4 Using Dynamic Cantilever Magnetometry
Authors: Li 李 Qi 奇 , Zhen 甄 Weili 伟立 , Wang 王 Ning 宁 , Shi 史 Meng 猛 , Yu 余 Yang 洋 , Pan 潘 Senyang 森洋 , Deng 邓 Lin 淋 , Cai 蔡 Jiaqiang 佳强 , Wang 王 Kang 康 , Zou 邹 Lvkuan 吕宽 , Zeng 曾 Zhongming 中明 , Wang 王 Zhaosheng 钊胜 , Zhang 张 Jinglei 警蕾
Published: September 2024

Recent experimental and theoretical work has focused on two-dimensional van der Waals (2D vdW) magnets due to their potential applications in sensing and spintronics devises. In measurements of these emerging materials, conventional magnetometry often encounters challenges in characterizing the magnetic properties of small-sized vdW materials, especially for antiferromagnets with nearly compensated magnetic moments. Here, we investigate the magnetism of 2D antiferromagnet CrPS4 with a thickness of 8 nm by using dynamic cantilever magnetometry (DCM). Through a combination of DCM experiment and the calculation based on a Stoner–Wohlfarth-type model, we unravel the magnetization states in 2D CrPS4 antiferromagnet. In the case of H ∥ c, a two-stage phase transition is observed. For H ⊥ c, a hump in the effective magnetic restoring force is noted, which implies the presence of spin reorientation as temperature increases. These results demonstrate the benefits of DCM for studying magnetism of 2D magnets.
Kalman-based estimation of loading conditions from ultrasonic guided wave measurements
Authors: Dalmora André , Imperiale Alexandre , Imperiale Sébastien , Moireau Philippe
Published: September 2024

Ultrasonic guided wave-based structural health monitoring (SHM) of structures can be perturbed by environmental and operations conditions (EOCs) that alter wave propagation. In this work, we present an estimation procedure to reconstruct an EOC-free baseline of the structure from the only available Ultrasonic guided wave measurements. This procedure could typically be used as a prior step to increase the robustness of a more general ultrasonic imaging algorithm or SHM process dedicated to flaw detection. Our approach is model-based, i.e. we use a precise modeling of the wave propagation altered by structure loading conditions. This model is coupled with the acquired data through a data assimilation procedure to estimate the deformation caused by the unknown loading conditions. From a methodological point of view, our approach is original since we have proposed an iterated reduced-order unscented Kalman strategy, which we justify as an alternative to a Levenberg–Marquardt strategy for minimizing the non quadratic least-squares estimation criteria. Therefore, from a data assimilation perspective, we provide a quasi-sequential strategy that can valuably replace more classical variational approaches. Indeed, our resulting algorithm proves to be computationally very effective, allowing us to successfully apply our strategy to realistic 3D industrial SHM configurations.
Design of bi-axial piezoelectric MEMS micro mirror with gimbal actuator for dynamic decoupling
Authors: Yang Hui-Ming , Hsu Chih-Chen , Lin Po-Chun , Lin Hung-Yu , Chen Si-Han , Cheng Hao-Chien , Fang Weileun
Published: September 2024

This study presents a novel structural design of a bi-axial piezoelectric micro-electro-mechanical-systems scanning mirror aimed at preventing the dynamic coupling between the two scanning axes and avoiding distortion of the scanning pattern. In the proposed design, the gimbal actuator, constrained by torsional springs at both ends, not only serves as the torque generation component for the actuation of one axis but also acts as a pivot to prevent structural interference between the two axes during scanning. This approach achieves the advantages of decoupling and compactness simultaneously. Simulations indicate that the gimbal actuator experiences very small displacement during y-axis actuation, thus realizing the dynamic decoupling from the x-axis scanning unit. To evaluate the proposed designs, fabrication processes were adopted on a silicon-on-insulator wafer with a lead zirconium titanate film. The miniaturized scanners, featuring a mirror with a 1.2 mm diameter, were realized on a compact 5 × 5 mm2 chip. Measurements indicate that the resonant frequencies of x-axis and y-axis scanning are 2.69 kHz and 4.29 kHz, respectively, and the optical scanning angles reach 33° and 21° under an 8 Vpp driving voltage. Additionally, measurements show that the displacement ratio between the central mirror and the gimbal actuator can reach up to 17 during y-axis actuation, verifying the concept of dynamic decoupling. The bi-axial Lissajous scanning pattern with straight edges also demonstrates the effective decoupling by the proposed gimbal actuator design.
Oxidative stress-modifying effects of TiO2 nanoparticles with varying content of Ti3+(Ti2+) ions
Authors: Kireev Viktor , Bespalova Iryna , Prokopiuk Volodymyr , Maksimchuk Pavel , Hubenko Kateryna , Grygorova Ganna , Demchenko Lesya , Onishchenko Anatolii , Tryfonyuk Liliya , Tomchuk Oleksandr , Tkachenko Anton , Yefimova Svitlana
Published: September 2024

Nanoparticles (NPs) with reactive oxygen species (ROS)-regulating ability have recently attracted great attention as promising agents for nanomedicine. In the present study, we have analyzed the effects of TiO2 defect structure related to the presence of stoichiometric (Ti4+) and non-stoichiometric (Ti3+ and Ti2+) titanium ions in the crystal lattice and TiO2 NPs aggregation ability on H2O2- and tert-butyl hydroperoxide (tBOOH)-induced ROS production in L929 cells. Synthesized TiO2-A, TiO2-B, and TiO2-C NPs with varying Ti3+(Ti2+) content were characterized by x-ray powder diffraction, transmission electron microscopy, small-angle x-ray scattering, x-ray photoelectron spectroscopy, and optical spectroscopy methods. Given the role of ROS-mediated toxicity for metal oxide NPs, L929 cell viability and changes in the intracellular ROS levels in H2O2- and tBOOH-treated L929 cells incubated with TiO2 NPs have been evaluated. Our research shows that both the amount of non-stoichiometric Ti3+ and Ti2+ ions in the crystal lattice of TiO2 NPs and NPs aggregative behavior affect their catalytic activity, in particular, H2O2 decomposition and, consequently, the efficiency of aggravating H2O2- and tBOOH-induced oxidative damage to L929 cells. TiO2-A NPs reveal the strongest H2O2 decomposition activity aligning with their less pronounced additional effects on H2O2-treated L929 cells due to the highest amount of Ti3+(Ti2+) ions. TiO2-C NPs with smaller amounts of Ti3+ ions and a tendency to aggregate in water solutions show lower antioxidant activity and, consequently, some elevation of the level of ROS in H2O2/tBOOH-treated L929 cells. Our findings suggest that synthesized TiO2 NPs capable of enhancing ROS generation at concentrations non-toxic for normal cells, which should be further investigated to assess their possible application in nanomedicine as ROS-regulating pharmaceutical agents.
On formal series solutions to 4th-order quadratic homogeneous differential equations and their convergence
Authors: Hosoi Tatsuya
Published: September 2024

It is known that all τ functions of the Painlevé equations satisfy the fourth-order quadratic differential equation. Among them, for the III, V, and VI equations, it is possible to express the formal series solutions combinatorially by using conformal blocks. In this paper, we show the convergence of the formal series, including the solutions of more general equations. The convergence of the conformal block function also follows in the case c = 1 by the absolute convergence of τ series, since it is a partial sum of the τ series. We also characterized the form of a homogeneous quadratic equation with a series solution similar to the tau functions of the Painlevé equations.
Phase-change ultrasound contrast agents for proton range verification: towards an in vivo application
Authors: Carlier Bram , Heymans Sophie V , Collado-Lara Gonzalo , Musetta Luigi , Ingram Marcus , Toumia Yosra , Paradossi Gaio , Vos Hendrik J , Roskams Tania , D’hooge Jan , Van Den Abeele Koen , Sterpin Edmond , Himmelreich Uwe
Published: September 2024

Objective. In proton therapy, range uncertainties prevent optimal benefit from the superior depth-dose characteristics of proton beams over conventional photon-based radiotherapy. To reduce these uncertainties we recently proposed the use of phase-change ultrasound contrast agents as an affordable and effective range verification tool. In particular, superheated nanodroplets can convert into echogenic microbubbles upon proton irradiation, whereby the resulting ultrasound contrast relates to the proton range with high reproducibility. Here, we provide a first in vivo proof-of-concept of this technology. Approach. First, the in vitro biocompatibility of radiation-sensitive poly(vinyl alcohol) perfluorobutane nanodroplets was investigated using several colorimetric assays. Then, in vivo ultrasound contrast was characterized using acoustic droplet vaporization (ADV) and later using proton beam irradiations at varying energies (49.7 MeV and 62 MeV) in healthy Sprague Dawley rats. A preliminary evaluation of the in vivo biocompatibility was performed using ADV and a combination of physiology monitoring and histology. Main results. Nanodroplets were non-toxic over a wide concentration range (<1 mM). In healthy rats, intravenously injected nanodroplets primarily accumulated in the organs of the reticuloendothelial system, where the lifetime of the generated ultrasound contrast (<30 min) was compatible with a typical radiotherapy fraction (<5 min). Spontaneous droplet vaporization did not result in significant background signals. Online ultrasound imaging of the liver of droplet-injected rats demonstrated an energy-dependent proton response, which can be tuned by varying the nanodroplet concentration. However, caution is warranted when deciding on the exact nanodroplet dose regimen as a mild physiological response (drop in cardiac rate, granuloma formation) was observed after ADV. Significance. These findings underline the potential of phase-change ultrasound contrast agents for in vivo proton range verification and provide the next step towards eventual clinical applications.
Effect of Cr3C2 on wear behavior of Ni45 laser cladding coating
Authors: Liang Limeng , Feng Dawei , Ma Shuli , Zhang Jie , Ding Guohua
Published: September 2024

To improve the performance of engineering components subjected to severe wear, temperature fluctuations, and corrosive conditions in industries such as chemical, aerospace, and power plants, Ni45-based coatings with varying Cr3C2 contents (0%, 10%, 20%, and 30%) were applied to a 45-steel surface. The microstructure of these coatings was examined by scanning electron microscopy (SEM), and their wear resistance was compared. As the Cr3C2 content in the cladding layer increased, there was a notable improvement in its wear resistance. Specifically, when the Cr3C2 content reached 30% by weight, the wear resistance of the cladding layer exceeded that of the GCr15 steel. Furthermore, the adhesive wear between the cladding layer and the GCr15 steel diminished, while the oxidation wear of the GCr15 steel intensified. This study aims to elucidate the primary wear mechanisms of the Cr3C2/Ni45 cladding layer and offer valuable insight into improving the durability of engineering components in harsh environments.
Effect of Ag coatings prepared by magnetron sputtering on the wear properties of Ti6Al4V alloy
Authors: Huang Xinyu , Rong Wenjuan , Wang Jialin
Published: September 2024

Ag coatings were prepared on the surface of Ti6Al4V alloy by magnetron sputtering technique, and the effects of different Ag target power and sputtering time on the coating properties were investigated. The coating thickness was firstly measured by a step meter, and then the coatings obtained under different parameters were characterized by Vickers hardness tester, scratch tester, and friction wear tester. The variation in the furnace temperature had a significant effect on the hardness of the coatings: the coating thickness increased slightly with increasing temperature, but the increase was not dramatical. The Vickers hardness of the coatings showed a tendency to increase and then decrease with increasing temperature, reaching a peak at 150 °C. The hardness of the coatings was found to increase with increasing temperature and then decrease with increasing temperature. Scratch tests further showed that the coatings prepared in the range of 150 °C to 180 °C exhibited superior bond strength with the substrate. The wear morphology of the coatings showed that the coatings prepared at 150 °C had the best wear resistance. At this temperature, the flaking of the coating due to adhesive wear was significantly reduced, and the depth of scratches due to abrasive wear was also reduced. The variation of the Ag target power also had a significant effect on the hardness of the coatings. As the target power increases, the coating thickness increases significantly, and the Vickers hardness increases and then decreases, reaching a maximum at 12 W. The coatings prepared at 10 W show better performance in terms of scratch and wear patterns. These experimental results provide strong data support for the subsequent preparation of Ti6Al4V joint prostheses.
Different temperature-dependent fluorescence properties of CsPbBr3 nanorods and nanowires
Authors: Chen Fengjiao , Li Liting , Shen Xiong , Zhang Jing , Ma Siyu , Wang Yue , An Limin
Published: September 2024

The morphology of totally inorganic metal halide perovskites has a certain influence on their optoelectronic properties. In this study, one-dimensional CsPbBr3 nanorods (NRs) and nanowires (NWs) were arranged utilizing a boiling injection strategy. By controlling the processing time, NRs with a length of roughly 63 nm and NWs with a length of 300 nm were obtained, and it was found that the nanowires were grown from the nanorods. Temperature-dependent photoluminescence (PL) measurements were conducted on CsPbBr3 NRs and NWs, and NRs exhibit a more stable excitonic state at high temperatures (>240 K). This study provides a method to change the morphology of one-dimensional metal halide perovskite nanomaterials without doping, further promoting the application of one-dimensional all-inorganic perovskite materials in the field of optoelectronics.
Research on moisture absorption characterization of wound composites based on surface concentration modified model
Authors: Yang Zilong , Hu Yuxia , Li Wusheng , Yang Fujiang
Published: September 2024

Four groups of hygroscopic experiments of T700/epoxy composite wound rings at temperatures and humidities of 45°C/60%, 45°C/90%, 70°C/60%, and 70°C/90% were completed in order to study the moisture absorption characterization. Surface concentration correction models characterized by different types of functions such as linear, quadratic, sinusoidal, exponential, and others were proposed to establish a “three-stage” moisture absorption model, in which the initial stage was smooth, the middle stage grew rapidly, and the later stage tended to equilibrium. The theoretically predicted hygroscopic curves derived from quadratic and exponential functions were in good agreement with the experimental data, which revealed the difference in the moisture absorption characterization between the wound rings with high fiber volume and that of the laminates and fabrics and provided a basis for the prediction of the mechanical degradation and life of the wound composites in hygrothermal environments.
Influence of secondary peak temperature on simulated ICCGHAZ microstructure and toughness of high-strength low-alloy steels
Authors: Bao Liangliang , Xu Yanhong , Zhang Xinming , Jiang Jun
Published: September 2024

The ICCGHAZ specimens of laser-arc hybrid welding under various secondary peak temperatures were prepared using welding thermal simulation technology. Investigations were conducted into how the toughness and microstructure of the simulated ICCGHAZ specimens were correlated with the secondary peak temperature. Results showed that the size, distribution, and morphology of the M-A constituents in the ICCGHAZ specimens were primarily influenced by the secondary peak temperature. With this temperature at 760 °C, the blocky M-A constituents mostly aggregated into chains along the grain boundaries. As the secondary peak temperature reached 800 °C, while the blocky M-A constituents typically stayed close to the grain boundaries, the necklace M-A constituents began dispersing. The former austenite grain boundaries vanished as the M-A constituents migrated outward when the temperature further rose to 840 °C. At secondary peak temperatures of 760 °C and 800 °C, the volume proportion of the M-A constituents was 2.9% and 3.2%, respectively. In comparison, the volume fraction rapidly decreased to 0.9% at 840 °C. The size of the M-A constituents shrank as the secondary peak temperature rose, whereas the crack initiation energy Ei, crack propagation energy Ep, and impact energy Et increased. The toughness of the ICCGHAZ specimen was diminished because of the grain boundary necklace distribution characterization and the large size of the M-A constituents.
Application of instrument indentation test for residual stress characterization of 5083 aluminium alloy
Authors: Du Zhuotong , Zhao Rutao , Gao Chen , Chen Pei , Xu Kuilong
Published: September 2024

An abnormal cracking phenomenon occurred at the corner of a ventilation window on the 5083 aluminum alloy wallboard used in certain transportation equipment. The residual stresses of the wallboard were measured using an instrumented indentation test. Initially, stress loading was applied to the 5083 specimens using a residual stress loading device to verify the effectiveness of the instrument indentation test (IIT) for testing the residual stresses of 5083 aluminum alloy. Subsequently, IIT was conducted under static conditions at the serving site of the equipment, and the working stresses under dynamic conditions were detected using a strain monitor. The results indicate that the total tensile stress at the uncracked corner of the ventilation window has exceeded the 5083 yield strength, so excessive tensile stress is the main cause of the abnormal cracking of the wallboard.
Molecular dynamics simulation of irradiation damage accumulation in α-Fe and model alloy FeMn1.4Ni0.7
Authors: Zhang Wenqing , Wu Jiaxin , Zhou Feng , Chen Jinhong , Zhu Fei , Song Ligang , Ma Xianfeng
Published: September 2024

The neutron irradiation of RPV steel leads to the generation of defects and further degrades the mechanical properties. MD simulation was used to study the accumulated damage of α-Fe and model alloy FeMn1.4Ni0.7 at room temperature. Two methods of introducing PKA, i.e., concentrated irradiation and uniform irradiation, were performed. The simulation results showed that concentrated irradiation is beneficial for the clustering of vacancies and the formation of vacancy DLs <100>. All the types of interstitial DLs are 1/2 < 111 >, and all the types of vacancy DLs are < 100 >. The addition of Mn and Ni restrained the clustering of interstitials under uniform irradiation conditions.
Outer spiral drill rod lunar soil sampling resistance moment simulation study
Authors: Li Dehui , Luo Haitao , Li Yuxin , Dong Yuming
Published: September 2024

The task of unmanned automated sampling of China’s lunar exploration is to bring back lunar soil samples with a certain depth, and sampling of external auger drill pipe is the best way. The power and moment size of the lunar surface is limited, so a special design is required. In this paper, a unique structural model of a double-auger drilling tool is designed. It is a movement analysis of lunar soil and drill pipe. We use simulated lunar soil simulations and experiments. The Hertz-Mindlin slip-free model in the discrete element software EDEM was used for numerical simulation. Given the disadvantage of the large amount of computation of discrete elements, the “embedding simulation method” proposed in this paper reduces the amount of computation. When drilling 0.4m and 1m under lunar and earth gravity, the magnitude and influence of drill pipe rotation and vertical velocity on the drag moment were analyzed. We provide the relevant technical parameters of the real unmanned drilling activities on the lunar surface. Through simulation, the rationality parameters of several groups of drill pipe drilling are obtained to ensure the smooth progress of drilling.