bluuebunny/crossref_metadata_2025 huggingface dataset:
Tourism in pandemic: the role of digital travel vouchers in China
Authors: Chen Yingtong , Wu Fei , Zhang Dayong , Ji Qiang
Published: June 2024

The COVID-19 pandemic has created significant challenges to the global economy, especially within the tourism industry. Economic downturns and psychological barriers make it even more challenging to attract tourists back. This paper explores the stimulating effect of digital travel vouchers on tourist mobility, as well as the heterogeneous effects of different vouchers modes. Using monthly data on tourist inflows in 306 cities from September 2020 to December 2021, collected by a web-crawling tool, and manually gathered information of digital travel vouchers issued during this period, our analyses show that digital travel vouchers can boost tourist inflows. Their effectiveness, however, depends on the method of issuance and the total number distributed. Furthermore, significant spillover effects among neighboring cities are found through a spatial econometric model.
Engineering interfacial tissues: The myotendinous junction
Authors: Snow Finn , O'Connell Cathal , Yang Peiqi , Kita Magdalena , Pirogova Elena , Williams Richard J. , Kapsa Rob M. I. , Quigley Anita
Published: June 2024

The myotendinous junction (MTJ) is the interface connecting skeletal muscle and tendon tissues. This specialized region represents the bridge that facilitates the transmission of contractile forces from muscle to tendon, and ultimately the skeletal system for the creation of movement. MTJs are, therefore, subject to high stress concentrations, rendering them susceptible to severe, life-altering injuries. Despite the scarcity of knowledge obtained from MTJ formation during embryogenesis, several attempts have been made to engineer this complex interfacial tissue. These attempts, however, fail to achieve the level of maturity and mechanical complexity required for in vivo transplantation. This review summarizes the strategies taken to engineer the MTJ, with an emphasis on how transitioning from static to mechanically inducive dynamic cultures may assist in achieving myotendinous maturity.
Engraved complementary toroidal metasurfaces for potential energy harvesting applications in microwave band
Authors: Fanourakis G. , Markaki P. , Theodosi A. , Tsilipakos O. , Viskadourakis Z. , Kenanakis G.
Published: June 2024

In the current study, complementary metasurface units with toroidal geometry were fabricated, using the computer numerical control engraving method. The metasurfaces were engraved in copper-coated, FR-4 plates. The produced metasurfaces were electromagnetically characterized in the microwave regime. Furthermore, they were studied regarding their energy harvesting capability, in the microwave range, where they absorb electromagnetic energy. It was found that toroidal structures harvest energy from the incident microwaves and transform it to electric power, through a simple rectification circuit. Moreover, their energy harvesting efficiency was found to be comparable or even superior to those of others reported so far. Therefore, the hereby obtained experimental results evidently show that engraved toroidal metasurfaces could potentially be used as energy harvesters in the microwave regime.
The impact of matrix stiffness on hepatic cell function, liver fibrosis, and hepatocellular carcinoma—Based on quantitative data
Authors: Min Kiyoon , Karuppannan Sathish Kumar , Tae Giyoong
Published: June 2024

Over the past few decades, extensive research has explored the development of supportive scaffold materials for in vitro hepatic cell culture, to effectively mimic in vivo microenvironments. It is crucial for hepatic disease modeling, drug screening, and therapeutic evaluations, considering the ethical concerns and practical challenges associated with in vivo experiments. This review offers a comprehensive perspective on hepatic cell culture using bioscaffolds by encompassing all stages of hepatic diseases—from a healthy liver to fibrosis and hepatocellular carcinoma (HCC)—with a specific focus on matrix stiffness. This review begins by providing physiological and functional overviews of the liver. Subsequently, it explores hepatic cellular behaviors dependent on matrix stiffness from previous reports. For hepatic cell activities, softer matrices showed significant advantages over stiffer ones in terms of cell proliferation, migration, and hepatic functions. Conversely, stiffer matrices induced myofibroblastic activation of hepatic stellate cells, contributing to the further progression of fibrosis. Elevated matrix stiffness also correlates with HCC by increasing proliferation, epithelial-mesenchymal transition, metastasis, and drug resistance of HCC cells. In addition, we provide quantitative information on available data to offer valuable perspectives for refining the preparation and development of matrices for hepatic tissue engineering. We also suggest directions for further research on this topic.
How cytoskeletal crosstalk makes cells move: Bridging cell-free and cell studies
Authors: Conboy James P. , Istúriz Petitjean Irene , van der Net Anouk , Koenderink Gijsje H.
Published: June 2024

Cell migration is a fundamental process for life and is highly dependent on the dynamical and mechanical properties of the cytoskeleton. Intensive physical and biochemical crosstalk among actin, microtubules, and intermediate filaments ensures their coordination to facilitate and enable migration. In this review, we discuss the different mechanical aspects that govern cell migration and provide, for each mechanical aspect, a novel perspective by juxtaposing two complementary approaches to the biophysical study of cytoskeletal crosstalk: live-cell studies (often referred to as top-down studies) and cell-free studies (often referred to as bottom-up studies). We summarize the main findings from both experimental approaches, and we provide our perspective on bridging the two perspectives to address the open questions of how cytoskeletal crosstalk governs cell migration and makes cells move.
Sensitivity analysis on transient pressure of entrapped air pocket in deep stormwater tunnel system
Authors: Wang Yiran , Yu Xiaodong , Yu Chao , Zhang Jian , Xu Hui
Published: June 2024

In deep stormwater tunnel systems (DSTSs), entrapped air pockets are prone to pressurization and deformation during rapid filling, resulting in pressure surges that threaten system security. This study investigates the effects of structural and inflow parameters on peak pressures. To simulate the pressure surges of entrapped air pockets, a rigid-column model was developed for a simplified DSTS configuration comprising two shafts and one tunnel. The global sensitivities of the air pocket, system structure, and inflow parameters were calculated using the Extended Fourier Amplitude Sensitivity Test (EFAST), which employed indicators of the maximum pressure and relative increment. The results indicate that parameters related to the shape and initial state of the air pocket exert a substantial and direct effect on pressure surges in rapid filling, whereas tunnel system parameters tend to exhibit minimal influence. Notably, compared to the total inflow discharge, the flow difference between two shafts imposes a more significant and direct impact. For the maximum pressure of air pocket, the initial pressure and the maximum water level height of shafts demonstrate more pronounced effects. The proposed sensitivity analysis could be integrated into methodologies for system safety assessment, while the rigid-column model may be extended to accommodate multiple shafts and air pockets.
Dual operation modes of the Ge Schottky barrier metal–oxide–semiconductor field-effect transistor
Authors: Lidsky D. , Allemang C. R. , Hutchins-Delgado T. , James A. R. , Allen P. , Saleh Ziabari M. , Sharma P. , Bradicich A. M. , Kuo W. C.-H. , House S. D. , Lu T. M.
Published: June 2024

A germanium p-channel Schottky barrier metal–oxide–semiconductor field-effect transistor (SB-MOSFET) with germanium–platinum Schottky contacts is demonstrated experimentally. The fabrication process has a low thermal budget of 450° C and requires neither intentional doping nor ion implantation. At a temperature of 4 K, the p-channel SB-MOSFET turns on at a gate voltage of −1.6 V and shows a peak mobility of 500 cm2/V s at a carrier density of 3 × 1012 cm–2. Under high drain–source bias voltages, the device operates in an unconventional mode where the current is limited by the source contact. Injection of carriers from the source contact to the germanium channel is controlled by the gate bias, which modulates the Schottky barrier capacitively. The transconductance in this mode deviates from and is significantly higher than the value expected for a conventional MOSFET with the same geometry, mobility, and capacitance. Based on four-point current–voltage measurements, we present a theoretical band diagram of the device and give a physical picture for the observed high currents and transconductances.
Research on the excitation force and vortex dynamics characteristics of pump-jet propulsor induced by shafting whirling vibration: Non-uniform blade tip clearance
Authors: Zou Donglin , Xue Lin , Yang Yuze , Dong Xinguo , Ta Na , Rao Zhushi
Published: June 2024

The propulsion shafting whirling vibration causes non-uniform dynamic changes in the rotor tip clearance, which directly have a significant influence on the excitation force and vortex dynamic characteristics of the pump-jet propulsor. In the current study, based on improved delay detached eddy simulation, the influence of non-uniform blade tip clearance on the excitation force and vortex dynamics characteristics of the pump-jet propulsor is studied under design conditions. The results show that the application of propulsion shafting whirling vibration induces significant changes in the excitation force of the pump-jet propulsor. The rotor blades modulate the excitation forces of the stator blades and duct. The transverse and vertical excitation forces are more significant than the longitudinal excitation force. The magnitude change in the circular orbit shows a linear relationship with the excitation force magnitude. The characteristic frequency of the transverse and vertical excitation forces of each component is the shaft rotation frequency. In contrast, the characteristic frequency of the longitudinal excitation force is twice the shaft rotation frequency. In the elliptical orbit, the excitation force of each component is compressed or stretched in the time domain, and the dominant frequency is shifted in the frequency domain; there is no longer a linear relationship between the vibration magnitude change and the excitation force magnitude. Furthermore, an energy generation mechanism in the wake field of the pump-jet propulsor induces vortex frequency due to the whirling vibration of the propulsion shafting system.
Fluid–structure interaction of a marine rudder at incidence in the wake of a propeller
Authors: Magionesi F. , Dubbioso G. , Muscari R.
Published: June 2024

The structural response of a rudder in the wake of a marine propeller is investigated by one-way fluid–structure interaction approach. The unsteady pressure field gathered by detached eddy simulations is provided to a structural solver for the computation of deformations and stresses of the rudder. The study compares the structural response of the rudder at neutral and two equal and opposite rotations, which are representative of design conditions in straight motion and maneuvering conditions that are experienced under the action of the autopilot for course control or weak maneuvering. The analysis sheds light on the different structural behavior at the two opposite rotation angles, caused by asymmetrical variation along the span of the rudder of the angle of attack induced by the propeller slipstream, by considering the different role played by the tip and hub vortical systems. The test case consists of a rudder with a rectangular plane area and National Advisory Committee for Aeronautics 0015 sectional profile located past the E779A propeller. The propeller operates at low loading conditions, and the rudder is set at incidence δ=0∘,±4∘. The study shows that the response of the rudder is driven by flap and torsion and is asymmetric for the two and opposite rotations. The mean deformation and vibratory response are magnified for δ=−4∘ by at least 70% and 20% for the lateral and edgewise deflections, respectively, with respect to the opposite rudder incidence. In general, the excitation generated by the tip vortex is stronger than that of the hub vortex. In the most critical condition, at δ=−4∘, the excitation associated with the tip vortex is nearly double that of the hub vortex.
Development and characterization of AZ91/AlN magnesium matrix composites via friction stir processing
Authors: Kumar T. Satish , Thankachan Titus , Bhowmik Abhijit , Makki Emad , Giri Jayant , Das Shirsendu
Published: June 2024

Magnesium AZ91/AlN-based surface composites have been synthesized using the friction stir processing (FSP) technique. The influence of particle addition during FSP on microstructural and mechanical properties has been investigated. Composite plates of 5, 10, and 15 vol. % AlN were synthesized using two-pass FSP with an axial force of 10 KN, a tool travel speed of 40 mm/min, and a tool rotation speed of 1200 rpm. The AZ91/AlN surface composites were analyzed microscopically with the use of an optical microscope, an x-ray diffractometer, and a scanning electron microscope. The prepared composites were tested for hardness and tensile strength. Micrographs taken in the stir zone revealed a consistent distribution of AlN particles throughout the AZ91 matrix. The AZ91/AlN surface composites were tested for hardness and tensile strength, and the findings showed that the AlN particles improved the mechanical properties without significantly decreasing ductility. The fracture surfaces of the composites were studied, and the mechanisms of fracture were identified.
Hadamard acoustic correlated imaging based on photoacoustic modulation with a single transducer
Authors: Liang A. Xiaoqian , Bai B. Yanfeng , Jin C. Hang , Huang D. Xianwei , Tan E. Wei , Zhu F. Xiaohui , Jiang G. Tongji , Zou H. Xuanpengfan , Zhou I. Liyu , Fu J. Xiquan
Published: June 2024

Conventional ultrasound technology based on spot scanning or phased array encounters significant challenge in real-time imaging with a single detector. In this paper, we present a Hadamard acoustic correlated imaging based on photoacoustic modulation with one transducer. The process of accurately generating the Hadamard acoustic field is to apply the carbon-nanotubes–polydimethylsiloxane composite to absorb the optimized Hadamard basis pattern. Taking advantage of correlated imaging, our system without scanning can reduce imaging artifacts and its resolution could be about four times higher than that of traditional ultrasound imaging. The use of a single transducer rather than an array of transducers can reduce the cost of the imaging system. Therefore, the proposed scheme can find applications in biomedical imaging and nondestructive evaluation.
Energy dissipation and time–frequency analysis of characteristics induced by vortex breakdown in an axial flow pump
Authors: Song Xijie , Jin Yan , Wang Zhengwei , Presas Alexandre , Tang Fangping , Liu Chao
Published: June 2024

Vortex breakdown in a pump sump is a complex and negative factor for the pump. Different from my previous study that focused mainly on the development process of vortex and its damage to the pump, this paper is from a new perspective that studies the energy dissipation and time–frequency characteristics induced by vortex breakdown. The tested data of pressure and velocity in the process of vortex breakdown were obtained by the model. Considering the gas–liquid two-phase flow of the vortices, a new numerical simulation approach is conducted and verified. The results show that the development rules of vortex breakdown reveal that the breakdown is initiated near the blade. The residual disturbance in the flow field continues to propagate after vortex breakdown, inducing unstable flow inside the runner and causing additional energy dissipation. The time–frequency characteristics induced by vortex breakdown indicated that the runner rotation speed has a significant effect on the vortex breakdown. The frequency of vortex breakdown is relatively small under high-speed rotation. Through discussion, it can be concluded that in order to reduce the harm of vortex breakdown, it can take measures such as controlling the impeller rotation speed, stalling anti-vortex measures, and adjusting operating conditions.
Defect induced Raman shifts and bandgap engineering in layered SnSe2+δ bulks
Authors: Lu Hong , Zang Haotong , Lai Zhigang , An Wei , Ni Vera , Rodionova Valeria , Magomedov Kurban , Ren Xiao
Published: June 2024

In the context of the extensive application prospect of two-dimensional (2D) chalcogenides, we synthesized layered SnSe2+δ bulks with defects employing a hybrid chemical vapor transport-melt approach. Both the Eg and A1g Raman characteristic peaks in SnSe2+δ are dominated by cubic anharmonicity, coupled with nonlinear temperature dependencies below 140 K. Notably, the reduction in phonon energy observed in these vibrational modes can be ascribed to defect-mediated Raman scattering, irrespective of deficient or excess Se defects. However, the lower consistency in the Raman shifts of the in-plane Eg vibrations compared to the out-of-plane A1g modes suggests that the defects predominantly entail the absence of Se atoms and the substitutions of Sn by Se, delineating a continuum of Se-deficient and Se-enriched compositions. Furthermore, Se defects induce the contraction of the indirect bandgaps, facilitating a transition from medium to narrow bandgap semiconductors in SnSe2+δ, which underscores the tunable nature of the bandgaps through the incorporation of Se defects. These discoveries present an avenue for bandgap engineering and foster a deeper comprehension of the phonon and thermal properties of layered chalcogenides for further advanced technologies.
Revealing contrary contributions of the magnetic and lattice entropy to the inverse magnetocaloric effect in magnetic shape memory alloy
Authors: Emre B. , Yuce S. , Kavak E. , Saritas S. , Cicek M. M. , Yildirim O. , Duman E. , Albertini F. , Fabbrici S.
Published: June 2024

In this work, we studied the nature and dilemma of the inverse magnetocaloric effect using Ni50Mn36In14 magnetic shape memory alloy. In this context, the inverse magnetocaloric effects of Ni50Mn36In14 magnetic shape memory alloy polycrystalline samples were investigated as a function of annealing heat treatments by the thermo-magnetometry method. Two forms of Ni49TiMn36In14 magnetic shape memory alloy were studied: one that predominantly undergoes a magnetic phase transition and the other that exhibits both a magnetic and martensitic phase transition. The magnetic behaviors and magnetocaloric properties of these alloys were analyzed to investigate the competition between magnetic and lattice contributions to the total entropy change. Finally, the mutually contradictory role of magnetic and lattice contributions was demonstrated.
Integration of wavelet packet transform, residual convolution neural network, and support vector machine for series arc fault detection
Authors: Yin Zhendong , Xiao Chunyu
Published: June 2024

Series arc fault (SAF) poses a great challenge to the safe and stable operation of civil low-voltage distribution systems. For the accurate and rapid detection of SAF, this article proposes an SAF detection method using wavelet packet transform (WPT), residual convolution neural network (RCNN), and support vector machine (SVM). First, the raw current signal is decomposed into four wavelet components based on WPT. Then, the 1-D wavelet components are converted into 2-D matrices. Afterward, the matrices are input into RCNN through different channels. Finally, the detection results can be yielded by SVM. The effectiveness of the proposed method is verified based on offline experiments. The average detection accuracy of the proposed method is 99.72%, which is higher than that of the eight comparison methods. Moreover, the results of online experiments indicate that the detection time of the proposed method is less than 100 ms and can satisfy the requirement of standard 1699.
Time-dependent Kohn−Sham electron dynamics coupled with nonequilibrium plasmonic response via atomistic electromagnetic model
Authors: Huang Xunkun , Zhang Wenshu , Liang WanZhen
Published: June 2024

Computational modeling of plasmon-mediated molecular photophysical and photochemical behaviors can help us better understand and tune the bound molecular properties and reactivity and make better decisions to design and control nanostructures. However, computational investigations of coupled plasmon–molecule systems are challenging due to the lack of accurate and efficient protocols to simulate these systems. Here, we present a hybrid scheme by combining the real-time time-dependent density functional theory (RT-TDDFT) approach with the time-domain frequency dependent fluctuating charge (TD-ωFQ) model. At first, we transform ωFQ in the frequency-domain, an atomistic electromagnetic model for the plasmonic response of plasmonic metal nanoparticles (PMNPs), into the time-domain and derive its equation-of-motion formulation. The TD-ωFQ introduces the nonequilibrium plasmonic response of PMNPs and atomistic interactions to the electronic excitation of the quantum mechanical (QM) region. Then, we combine TD-ωFQ with RT-TDDFT. The derived RT-TDDFT/TD-ωFQ scheme allows us to effectively simulate the plasmon-mediated “real-time” electronic dynamics and even the coupled electron–nuclear dynamics by combining them with the nuclear dynamics approaches. As a first application of the RT-TDDFT/TD-ωFQ method, we study the nonradiative decay rate and plasmon-enhanced absorption spectra of two small molecules in the proximity of sodium MNPs. Thanks to the atomistic nature of the ωFQ model, the edge effect of MNP on absorption enhancement has also been investigated and unveiled.
Synthesis of Ni decorated MoOx nanorod catalysts for efficient overall urea–water splitting
Authors: Li Zhiwei , Yang Wenwen , Xiong Kun , Chen Jia , Zhang Haidong , Yang Mingliang , Gan Xing , Gao Yuan
Published: June 2024

Substituting slow oxygen evolution reaction (OER) with thermodynamically favorable urea oxidation reaction (UOR) is considered as one of the feasible strategies for achieving energy-saving hydrogen production. Herein, a uniform layer of NiMoO4 nanorods was grown on nickel foam by a hydrothermal method. Then, a series of Ni-MoOx/NF-X nanorod catalysts comprising Ni/NiO and MoOx (MoO2/MoO3) were prepared through regulating annealing atmosphere and reduction temperature. The optimized Ni-MoOx/NF-3 with a large accessible specific area can act as a bifunctional catalyst for electrocatalytic anodic UOR and cathodic hydrogen evolution reaction (HER). At a current density of 100 mA cm−2, the introduction of urea can significantly reduce the overpotential of Ni-MoOx/NF-3 by 210 mV compared to OER. In addition, Ni-MoOx/NF-3 has a higher intrinsic activity than other catalysts. It only requires −0.21 and 1.38 V to reach 100 mA cm−2 in HER and UOR, respectively. Such an excellent performance can be attributed to the synergistic function between Ni and MoOx. The presence of metallic Ni and reduced MoOx in pairs is beneficial for improving the electrical conductivity and modulating the electronic structure, resulting in enhancing the electrocatalytic performance. When assembling Ni-MoOx/NF-3 into an overall urea–water splitting system, it can achieve energy-saving hydrogen production and effective removal of urea-rich wastewater.
Numerical simulations and theoretical analysis of the forward shock wave in a non-premixed air-breathing rotating detonation combustor
Authors: Gao Sijia , Peng Han , Huang Yue , Sun Zhipeng , You Yancheng
Published: June 2024

The forward shock wave induced by the detonation wave propagates in the inlet and restrains the air from being injected into the rotating detonation engine, and the stable continuous propagation of the detonation wave is affected. Numerical simulation and theoretical derivation of air flow velocity and detonation wave height were carried out in a rotating detonation combustor. The influence of the forward shock wave on air flow velocity and air flow velocity on detonation wave height was analyzed. A non-premixed air-breathing rotating detonation combustor was numerically simulated with the two-dimensional Navier–Stokes equations and a kerosene/air reaction model based on the RYrhoCentralFoam solver. Analytical equations were derived and validated to calculate the air flow velocity across the forward shock wave and the height of the detonation wave. The results show that the air flow velocity across the forward shock wave is inversely proportional to the detonation wave velocity, incoming flow temperature, and pressure ratio at the forward shock wave. In addition, the angle of the forward shock wave is inversely proportional to the velocity of the detonation wave and incoming flow and is proportional to the incoming flow temperature and the pressure ratio. The forward shock wave leads to a blocked zone of injection in the combustor, as the inflow velocity decreases or even reverses across the shock wave. As a result, the forward shock wave induced by the detonation wave restrains the recovery of the reactant fill zone, which has an influence on the height of the detonation wave.
Liouville models of particle-laden flow
Authors: Domínguez-Vázquez Daniel , Jacobs Gustaaf B. , Tartakovsky Daniel M.
Published: June 2024

Langevin (stochastic differential) equations are routinely used to describe particle-laden flows. They predict Gaussian probability density functions (PDFs) of a particle's trajectory and velocity, even though experimentally observed dynamics might be highly non-Gaussian. Our Liouville approach overcomes this dichotomy by replacing the Wiener process in the Langevin models with a (small) set of random variables, whose distributions are tuned to match the observed statistics. This strategy gives rise to an exact (deterministic, first-order, hyperbolic) Liouville equation that describes the evolution of a joint PDF in the augmented phase-space spanned by the random variables and the particle position and velocity. Analytical PDF solutions for canonical models of particle-laden flows serve to establish a relationship between the Langevin and Liouville approaches. Finally, our framework is used to derive a new analytical PDF model for fluidized homogeneous heating systems.
Quasi-2D-Ising-type magnetic critical behavior in trigonal Cr1.27Te2
Authors: Goswami Anirban , Ng Nicholas , Yakubu Emmanuel , Bassen Gregory , Guchhait Samaresh
Published: June 2024

Single crystal Cr1.27Te2 samples were synthesized by using the chemical vapor transport method. Single crystal x-ray diffraction studies show a trigonal crystal structure with a P3̄m1 symmetry space group. We then systematically investigate magnetic properties and critical behaviors of single crystal Cr1.27Te2 around its paramagnetic-to-ferromagnetic phase transition. The Arrott plot indicates a second-order magnetic phase transition. We estimate critical exponents β = 0.2631 ± 0.002, γ = 1.2314 ± 0.007, and TC = 168.48 ± 0.031 K by using the Kouvel–Fisher method. We also estimate other critical exponents δ = 5.31 ± 0.004 by analyzing the critical isotherm at TC = 168.5 K. We further verify the accuracy of our estimated critical exponents by the scaling analysis. Further analysis suggests that Cr1.27Te2 can be best described as a quasi-2D Ising magnetic system.
Optimal photoelectron circular dichroism of a model chiral system
Authors: von Rudorff Guido F. , Artemyev Anton N. , Lagutin Boris M. , Demekhin Philipp V.
Published: June 2024

We optimize the internuclear geometry and electronic structure of a model chiral system to achieve a maximal photoelectron circular dichroism (PECD) in its one-photon ionization by circularly polarized light. The electronic structure calculations are performed by the single center method, while the optimization is done using quantum alchemy employing a Taylor series expansion. Thereby, the effect of bond lengths and uncompensated charge distributions on the chiral response of the model is investigated theoretically in some detail. It is demonstrated that manipulating a chiral asymmetry of the ionic potential may enhance the dichroic parameter (i.e., the PECD) of the randomly oriented model system well beyond β1 = 25%. Furthermore, we demonstrate that quantum alchemy is applicable to PECD despite the unusually strong coupling of spatial and electronic degrees of freedom and discuss the relative impact of the individual degrees of freedom in this model system. We define the necessary conditions for the computational design of PECD for real (non-model) chiral molecules using our approach.
Improving the prediction of turbulent kinetic energy for drag reduction in turbulent viscoelastic pipe flow
Authors: Niazi Mohammad , Ashrafizadeh Seyed Nezameddin , Hashemabadi Seyed Hassan
Published: June 2024

Reducing turbulence in pipe flows using polymer additives is crucial for industrial applications like crude oil, water, and sewage transportation. While previous research has accurately predicted friction factor and velocity profiles, none has fully understood turbulent kinetic energy (TKE) behavior in such fluids. Authors are now focusing on exploring turbulence models to better understand the TKE behavior. In this research, we have introduced a model to improve the behavior of TKE in a modified generalized Newtonian fluid (GNF). The developed model aims to simulate the viscoelastic effects of fluids that result in drag reduction in turbulent pipe flow. The work is noteworthy as it integrates turbulence and viscoelastic components, offering a comprehensive understanding of the phenomenon. By incorporating the rheological properties of viscoelastic fluids and replacing the damping function with a non-Newtonian alternative proposed by Cruz and Pinho, the Launder–Sharma k–ε turbulence model is now suitable for simulating dilute non-Newtonian viscoelastic fluids. The viscoelastic aspect of the model employs the modified GNF model. The developed model has been subjected to simulations using the computational fluid dynamics software. The results obtained for fluid TKE demonstrate a significant improvement in comparison to our previous research and the findings of other researchers. Furthermore, the model's prediction for the Darcy friction factor has been enhanced, resulting in an average error of only 3.71% in this section. It is noteworthy that the model consistently maintains a high level of accuracy in predicting other essential flow parameters such as mean axial velocity and Reynolds stresses. The provided model advances our understanding of viscoelastic fluid behavior in turbulent pipe flow by applying the modified GNF model.
A high-order upwind compact difference scheme for solving the streamfunction-velocity formulation of the unsteady incompressible Navier–Stokes equations
Authors: Yu Peixiang , Wang Bo , Ouyang Hua
Published: June 2024

In this paper, we propose an upwind compact difference method with fourth-order spatial accuracy and second-order temporal accuracy for solving the streamfunction-velocity formulation of the two-dimensional unsteady incompressible Navier–Stokes equations. The streamfunction and its first-order partial derivatives (velocities) are treated as unknown variables. Three types of compact difference schemes are employed to discretize the first-order partial derivatives of the streamfunction. Specifically, these schemes include the fourth-order symmetric scheme, the fifth-order upwind scheme, and the sixth-order symmetric scheme derived by combining the two parts of the fifth-order upwind scheme. As a result, the fourth-order spatial discretization schemes are established for the Laplacian term, the biharmonic term, and the nonlinear convective term, along with the Crank–Nicolson scheme for the temporal discretization. The unconditional stability characteristic of the scheme for the linear model is proved by discrete von Neumann analysis. Moreover, six numerical experiments involving three test problems with the analytic solutions, and three flow problems including doubly periodic double shear layer, lid-driven cavity flow, and dipole-wall interaction are carried out to demonstrate the accuracy, robustness, and efficiency of the present method. The results indicate that the present method not only has good numerical performance but also exhibits quite efficiency.
Nanometer-scale electron beam shaping with thickness controlled and stacked nanostructured graphite
Authors: Haas Jonas , Rieger Nils , Schlegel Michael , Strobel Kevin , Meyer Jannik C.
Published: June 2024

The generation of small electron probes is the basis for various techniques in which such a probe is scanned across a sample, and special probe shapes like vortices can be desirable, e.g., to gain insight into magnetic properties. Micron-scale phase plates or holographic masks, in combination with demagnifying optics, are usually used for creating such special probe wave functions. Here, we present the fabrication of nanometer-sized phase plates based on thickness-selected and stacked graphite layers as well as an analysis of their performance. First, a spiral phase plate is demonstrated that creates a vortex beam with an orbital angular momentum of 1 and an outer radius of 2.5 nm. Second, a three-level Fresnel lens built from two nanopatterned graphite membranes is presented, which achieves a focal spot with a full width at half maximum of 5.5 nm. Third, an array of electron sieves is demonstrated, each of which creates a focal spot with a radius of 2 nm, and the array is applied as a Shack–Hartmann wavefront detector. These elements allow the generation of few-nanometer sized focused probes or vortices without the need for additional optical elements.
Experimental study on mechanical properties of alkali activated concrete after freeze–thaw cycles
Authors: Wang Yuhua , Chen Shuai , Tang Congrong , Yu Yong
Published: June 2024

In order to study the frost resistance of alkali activated concrete (AAC), 15 AAC cube specimens and 15 cylindrical specimens were designed and manufactured. The frost thawing cycle test and mechanical performance test were used to study the frost resistance of AAC. The results showed that after freeze–thaw cycles, small pores appeared on the surface of the specimen, and the surface roughness increased, resulting in a darker appearance. As the number of freeze–thaw cycles increases, the highest mass loss rate of AAC reaches 1.88%. The cube compressive strength and axial compressive strength of AAC first increase and then decrease, while the elastic modulus gradually decreases. After 50 freeze–thaw cycles, the compressive strength of the specimen was greater than that of the normal temperature specimen. When the freeze–thaw cycles reached 200, the elastic modulus of the specimen degraded by 9.7%, the compressive strength decreased by 18.6%, and the axial compressive strength decreased by 31.2%. Based on the experimental results, a method for calculating the residual strength of AAC after freeze–thaw cycles and key parameters of the freeze–thaw damage constitutive equation were proposed.
Low-defect and stress-free AlN(0001) nanoprisms and microrods selectively grown on micro-patterned c-sapphire substrate by plasma-assisted molecular beam epitaxy
Authors: Jmerik V. N. , Semenov A. N. , Nechaev D. V. , Troshkov S. I. , Sakhno D. D. , Alekseev P. A. , Kirilenko D. A. , Eliseyev I. A. , Davydov V. Yu. , Abbas A. S.
Published: June 2024

This paper describes different growth modes of AlN layers on micro-cone patterned c-sapphire substrates (μ-PSSs) using plasma-assisted molecular beam epitaxy. Ordered arrays of AlN nanoprisms and microrods were selectively grown on the tips of μ-PSS's microcones according to a bottom-up formation mechanism using sequential migration enhanced and metal-modulated epitaxy (MME) under metal-rich growth conditions at 820 °C. Transmission electron microscopy revealed structurally perfect AlN regions above the tips of the μ-PSSs, which initiate as inverted nanopyramids with {1011¯} side faces, evolving into hexagonal nanoprisms with orientations of {11¯00} and (0001) for side and top surfaces, respectively. The diameter and height of these ordered hexagonal nanoprisms, which have a 60% probability of nucleating, were about 1 μm. Long-term MME growth of these nanoprisms in both vertical and lateral directions led to the formation of AlN(0001) microrods with a maximum possible diameter of two micrometers and a height of up to 6 μm. Atomic force microscopy revealed a mixed step-flow and 2D nucleation growth mechanism for the flat tops of these AlN nanoprisms and microrods with an average surface roughness of 1–2 monolayers. Micro-Raman spectroscopy demonstrated narrow E2 (high) linewidths of 3.8 and 4.2 cm−1 for essentially stress-free AlN nanoprisms and microrods, respectively.
Variation in direct healthcare costs to the health system by residents living in long-term care facilities: a Registry of Senior Australians study
Authors: Khadka Jyoti , Ratcliffe Julie , Caughey Gillian , Air Tracy , Wesselingh Steve , Corlis Megan , Evans Keith , Inacio Maria
Published: June 2024

Objective This study aimed to examine the national variation in government-subsidised healthcare costs of residents in long-term care facilities (LTCFs) and costs differences by resident and facility characteristics. Methods A retrospective population-based cohort study was conducted using linked national aged and healthcare data of older people (≥65 years) living in 2112 LTCFs in Australia. Individuals’ pharmaceutical, out-of-hospital, hospitalisation and emergency presentations direct costs were aggregated from the linked healthcare data. Average annual healthcare costs per resident were estimated using generalised linear models, adjusting for covariates. Cost estimates were compared by resident dementia status and facility characteristics (location, ownership type and size). Results Of the 75,142 residents examined, 70% (N = 52,142) were women and 53.4% (N = 40,137) were living with dementia. The average annual healthcare cost (all costs in $A) was $9233 (95% CI $9150–$9295) per resident, with hospitalisation accounting for 47.2% of the healthcare costs. Residents without dementia had higher healthcare costs ($11,097, 95% CI $10,995–$11,200) compared to those with dementia ($7561, 95% CI $7502–$7620). Residents living in for-profit LTCFs had higher adjusted average overall annual healthcare costs ($11,324, 95% CI $11,185–$11,463) compared to those living in not-for-profit ($11,017, 95% CI $10,895–$11,139) and government ($9731, 95% CI $9365–$10,099) facilities. Conclusions The healthcare costs incurred by residents of LTCFs varied by presence of dementia and facility ownership. The variation in costs may be associated with residents’ care needs, care models and difference in quality of care across LTCFs. As hospitalisation is the biggest driver of the healthcare costs, strategies to reduce preventable hospitalisations may reduce downstream cost burden to the health system.
Congeneric and sympatric tropical mullets respond differently to environmental variability: insights into coexistence
Authors: Rangely Jordana , de Barros Matheus , Souto-Vieira Daniele , Oliveira Maria das Neves Tayana S. C. , da Silva Victor E. L. , de Assis Ivan Oliveira , Fabré Nidia N.
Published: June 2024

Context Disentangling mechanisms influencing the seasonal and spatial distribution of fish is essential to understanding population dynamics. In the south-western Atlantic, the sympatric mullets Mugil curema and M. rubrioculus are closely related and use habitat similarly. However, which processes allow their coexistence is unknown. Aims We tested the hypothesis that the two species exhibit temporally and spatially decoupled habitat-use patterns to allow sympatry due to different responses to environmental drivers. Methods Bayesian zero-inflated count models were used to unravel spatial and temporal distribution patterns of those species in a south-western Atlantic lagoon. Key results The two species display different distributions within the estuary, being spatially and temporally segregated, with M. curema mostly inhabiting the inner estuary and M. rubrioculus inhabiting coastal marine habitats. Conclusions This decoupling in habitat use might be driven by distinct responses to environmental variability: M. curema is influenced by factors such as temperature and dissolved oxygen, whereas M. rubrioculus is influenced by variations in salinity. We suggest that the studied species evolved divergent responses to environmental variation to allow coexistence. Implications This study suggests that environmental factors drive mullet abundance, and that zero-inflated count models incorporating those drivers are therefore useful in predicting their spatial and temporal distribution, as well as in standardising abundance trends for stock assessment efforts.
Bispecific antibodies targeting two glycoproteins on SFTSV exhibit synergistic neutralization and protection in a mouse model
Authors: Chang Zhen , Gao Dan , Liao Liying , Sun Junqing , Zhang Gen , Zhang Xue , Wang Feiran , Li Chunrui , Oladejo Babayemi Olawale , Li Shihua , Chai Yan , Hu Yongfei , Lu Xuancheng , Xiao Haixia , Qi Jianxun , Chen Zhihai , Gao Feng , Wu Yan
Published: June 2024

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with a high fatality rate of up to 30% caused by SFTS virus (SFTSV). However, no specific vaccine or antiviral therapy has been approved for clinical use. To develop an effective treatment, we isolated a panel of human monoclonal antibodies (mAbs). SF5 and SF83 are two neutralizing mAbs that recognize two viral glycoproteins (Gn and Gc), respectively. We found that their epitopes are closely located, and we then engineered them as several bispecific antibodies (bsAbs). Neutralization and animal experiments indicated that bsAbs display more potent protective effects than the parental mAbs, and the cryoelectron microscopy structure of a bsAb3 Fab–Gn–Gc complex elucidated the mechanism of protection. In vivo virus passage in the presence of antibodies indicated that two bsAbs resulted in less selective pressure and could efficiently bind to all single parental mAb-escape mutants. Furthermore, epitope analysis of the protective mAbs against SFTSV and RVFV indicated that they are all located on the Gn subdomain I, where may be the hot spots in the phleboviruses. Collectively, these data provide potential therapeutic agents and molecular basis for the rational design of vaccines against SFTSV infection.
The Application of Scientific Evidence-Based Changes to an Animal Shelter’s Rehoming Practices
Authors: Griffin Karen E.
Published: June 2024

Shelters devote much of their often very limited resources to screening potential adopters, including spending copious amounts of time collecting information from them about their family structure, lifestyle, etc. However, in a study that surveyed rehoming organisations’ practices, it was found that they gather substantially more information about potential adopters than there is scientific evidence to justify. Some information gathered for which there is no scientific rationale which could cause adopters to be denied adopting any dog from the organisation. Consequently, the study concluded that organisations may be turning away perfectly suitable homes due to their often strict rehoming criteria, resulting in dogs staying with the organisation for longer than necessary. Therefore, the study recommended organisations relax their strict rehoming criteria and instead focus on ensuring adopters have appropriate expectations and education for adopting a dog. With knowledge of the study’s findings, a shelter in Northern Ireland overhauled their rehoming practices to be in line with the study’s recommendations for change. Their goal was to increase the number of animals adopted per month with a focus on ensuring successful placements, to decrease staff/volunteer workload, and for potential adopters to have an overall better experience with the shelter. Despite challenges in uptake of the changes by staff working with dogs, noteworthy improvements were observed, with the greatest improvements with cats and small animals. Three months after the shelter overhauled their rehoming practices, adoptions increased year-over-year, staff motivation and morale improved and potential adopters reported a more positive experience with the organisation.

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Cherenkov radiation in a bianisotropic medium with magnetoelectric effect
Authors: Fakhrzadeh Elham , Shahabadi Mahmoud , Talebi Nahid
Published: June 2024

Cherenkov radiation (CR) has been extensively explored in a large variety of media; however, its characteristics in a medium showing both magnetoelectric (ME) and anisotropy effects have not been addressed so far. The aim of this study is to address this gap by analytically investigating CR in a dispersive bianisotropic medium with ME effect. In this research, founded upon a vector-potential approach, we demonstrate that notable features such as double cones of CR with different angles can be formed due to ME coupling in bianisotropic media. We also calculate the emitted electromagnetic fields to obtain radiated power and momentum-resolved electron energy-loss spectra for a medium with varying ME coefficients, as well as for a medium without ME effects in order to illustrate the impact of this coupling on the characteristics of the CR and propose methods for the characterization of ME materials.
Generation and applications of x-ray and extreme ultraviolet beams carrying orbital angular momentum
Authors: McCarter Margaret R , De Long Lance E , Todd Hastings J , Roy Sujoy
Published: June 2024

In addition to spin angular momentum, light can carry orbital angular momentum. The orbital angular momentum degree of freedom in the extreme ultraviolet and x-ray regimes enables fundamental studies of light–matter interactions and new methods to study materials. Advances in x-ray optics, as well as undulator radiation and high harmonic generation techniques, lead to the creation of beams with non-trivial phase structure, such as a helical phase structure, creating new possibilities for the use of extreme ultraviolet and x-ray photons with orbital angular momentum in probing complex electronic structures in matter. In this article, we review the generation and applications of orbital angular momentum beams in the x-ray and extreme ultraviolet regime. We discuss several recent works that exploit the orbital angular momentum degree of freedom and showcase the potential advantages of using these beams.