bluuebunny/crossref_metadata_2025 huggingface dataset:
Long-Term Outcomes in Severe Community-Acquired Pneumonia
Authors: Carella Francesco , Aliberti Stefano , Stainer Anna , Voza Antonio , Blasi Francesco
Published: February 2024

Community-acquired pneumonia (CAP) is globally one of the major causes of hospitalization and mortality. Severe CAP (sCAP) presents great challenges and need a comprehensive understanding of its long-term outcomes. Cardiovascular events and neurological impairment, due to persistent inflammation and hypoxemia, contribute to long-term outcomes in CAP, including mortality. Very few data are available in the specific population of sCAP. Multiple studies have reported variable 1-year mortality rates for patients with CAP up to 40.7%, with a clear influence by age, comorbidities, and disease severity. In terms of treatment, the potential protective role of macrolides in reducing mortality emphasizes the importance of appropriate empiric antibiotic therapy. This narrative review explores the growing interest in the literature focusing on the long-term implications of sCAP. Improved understanding of long-term outcomes in sCAP can facilitate targeted interventions and enhance posthospitalization care protocols.
Radiation-driven diffusive transport of fast electrons in solar flares
Authors: Duclous R. , Tikhonchuk V. , Gremillet L. , Martinez B. , Leroy T. , Masson Laborde P.-E. , Pain J.-C. , Decoster A.
Published: February 2024

Fast electron scattering on plasma ions due to stimulated Bremsstrahlung is investigated and modeled. Comparison with Coulomb scattering suggests that stimulated Bremsstrahlung scattering can be dominant in low-density, radiation-driven plasmas, provided that the radiation spectrum has a sufficiently high brightness temperature in the neighborhood of the plasma frequency. While stimulated Bremsstrahlung scattering cannot be easily observed in laboratory plasmas due to their small size, it should operate in large-scale astrophysical plasmas, such as those met in the flaring solar corona. The effect of the solar microwave radiation on fast-electron scattering is evaluated through a parameterized flaring corona model. We find that stimulated Bremsstrahlung greatly enhances the fast-electron scattering frequency in the flare magnetic loop, leading the transport of deka-keV electrons to occur in the diffusion regime, characterized by significant precipitation rates. This prediction is consistent with the interpretation of the above-loop-top hard x-ray and microwave emissions from the X3.1 flare of August 24, 2002. Our analysis indicates that stimulated Bremsstrahlung may play an essential role in the dynamics of fast electrons trapped in solar flare loops.
Spectroradiometry with sub-microsecond time resolution using multianode photomultiplier tube assemblies
Authors: Geballe Zachary M. , Miozzi Francesca , Anto Chris F. , Rojas Javier , Yang Jing , Walter Michael J.
Published: February 2024

Accurate and precise measurements of spectroradiometric temperature are crucial for many high pressure experiments that use diamond anvil cells or shock waves. In experiments with sub-millisecond timescales, specialized detectors such as streak cameras or photomultiplier tubes are required to measure temperature. High accuracy and precision are difficult to attain, especially at temperatures below 3000 K. Here, we present a new spectroradiometry system based on multianode photomultiplier tube technology and passive readout circuitry that yields a 0.24 µs rise-time for each channel. Temperature is measured using five color spectroradiometry. During high pressure pulsed Joule heating experiments in a diamond anvil cell, we document measurement precision to be ±30 K at temperatures as low as 2000 K during single-shot heating experiments with 0.6 µs time-resolution. Ambient pressure melting tests using pulsed Joule heating indicate that the accuracy is ±80 K in the temperature range 1800–2700 K.
Pore-scale prediction of the effective mass diffusivity and apparent permeability of carbon gels with adjustable nanoporous characteristics
Authors: Dai Jia-Peng , Du Shen , He Ya-Ling
Published: February 2024

To explore the structural effects on transport properties in carbon gels, an improved method has been introduced to regenerate their nanostructure and numerically illustrate the adjustability of their porous characteristics with the variation of synthesis parameters. Two lattice Boltzmann equations are applied to investigate the permeation and diffusion in the gel structures at the pore scale, and the apparent permeability is formulated to describe the total mass flux using the dusty gas model. The structural properties of the reconstructed models and calculated apparent permeabilities have been fully validated by various experiments. A decoupled analysis of the impact of structural parameters on transport properties demonstrates that increasing porosity and pore size, while decreasing geometric tortuosity, leads to more pronounced changes in intrinsic permeability compared to gas diffusivity. By utilizing a database that encompasses 240 reconstructed gels, a structural–functional relationship for transport properties in carbon gels could be proposed. Concerning the intrinsic permeability, a near quadratic relationship with the porosity and mean pore size, independent of particle size, could be concluded. For the nondimensional effective diffusivity, a power exponent of 1.85 associated with porosity is proposed, and its independence of pore size could be revealed. In addition, for gels with porosities under 0.65 and mean pore sizes less than 133 nm, diffusion supersedes permeation as the dominant term in total mass transfer, indicating that particle sizes have a more pronounced influence on the apparent permeability. The predictive model offers guidance for tailoring the transfer properties of carbon gels at the stage of preparation.
Study on the single-event burnout mechanism of GaN MMIC power amplifiers
Authors: Zhang Hao , Zheng Xuefeng , Lin Danmei , Lv Ling , Cao Yanrong , Hong Yuehua , Zhang Fang , Wang Xiaohu , Wang Yingzhe , Zhang Weidong , Zhang Jianfu , Ma Xiaohua , Hao Yue
Published: February 2024

In this Letter, a single-event burnout (SEB) mechanism in gallium nitride (GaN) microwave monolithic integrated circuit power amplifiers with a high linear energy transfer of 78.1 MeV·cm2/mg has been investigated in detail. A typical SEB phenomenon was observed. With the aid of photon emission measurements and scanning electron microscopy, it is found that catastrophic burnout occurs in the power-stage GaN high electron mobility transistors (HEMTs) and the metal–insulator–metal (MIM) capacitors, respectively. For the GaN HEMT, the incident heavy ions will generate electron–hole pairs within it, which can gain enough energy with the transverse high electric field. The high-energy electrons will collide with the lattice near the drain electrode and induce significant electron trapping, which will result in a significant longitudinal local electric field. When a critical electric field is achieved, catastrophic burnout occurs. For the MIM capacitor, the burnout is attributed to the single-event dielectric rupture via severe impact ionization or latent tracks when heavy ions strike it.
Physically constrained eigenspace perturbation for turbulence model uncertainty estimation
Authors: Matha Marcel , Morsbach Christian
Published: February 2024

Aerospace design is increasingly incorporating design under uncertainty-based approaches to lead to more robust and reliable optimal designs. These approaches require dependable estimates of uncertainty in simulations for their success. The key contributor of predictive uncertainty in computational fluid dynamics (CFD) simulations of turbulent flows are the structural limitations of Reynolds-averaged Navier–Stokes models, termed model-form uncertainty. Currently, the common procedure to estimate turbulence model-form uncertainty is the eigenspace perturbation framework (EPF), involving perturbations to the modeled Reynolds stress tensor within physical limits. The EPF has been applied with success in design and analysis tasks in numerous prior works from the industry and academia. Owing to its rapid success and adoption in several commercial and open-source CFD solvers, in-depth verification and validation of the EPF is critical. In this work, we show that under certain conditions, the perturbations in the EPF can lead to Reynolds stress dynamics that are not physically realizable. This analysis enables us to propose a set of necessary physics-based constraints, leading to a realizable EPF. We apply this constrained procedure to the illustrative test case of a converging-diverging channel, and we demonstrate that these constraints limit physically implausible dynamics of the Reynolds stress tensor, while enhancing the accuracy and stability of the uncertainty estimation procedure.
Interfacial chemical reactivity enhancement
Authors: Ben-Amotz Dor
Published: February 2024

Interfacial enhancements of chemical reaction equilibria and rates in liquid droplets are predicted using a combined theoretical and experimental analysis strategy. Self-consistent solutions of reaction and adsorption equilibria indicate that interfacial reactivity enhancement is driven primarily by the adsorption free energy of the product (or activated complex). Reactant surface activity has a smaller indirect influence on reactivity due to compensating reactant interfacial concentration and adsorption free energy changes, as well as adsorption-induced depletion of the droplet core. Experimental air-water interfacial adsorption free energies and critical micelle concentration correlations provide quantitative surface activity estimates as a function of molecular structure, predicting an increase in interfacial reactivity with increasing product size and decreasing product polarity, aromaticity, and charge (but less so for anions than cations). Reactions with small, neutral, or charged products are predicted to have little reactivity enhancement at an air–water interface unless the product is rendered sufficiently surface active by, for example, interactions with interfacial water dangling OH groups, charge transfer, or voltage fluctuations.
Accurate estimates of dynamical statistics using memory
Authors: Lorpaiboon Chatipat , Guo Spencer C. , Strahan John , Weare Jonathan , Dinner Aaron R.
Published: February 2024

Many chemical reactions and molecular processes occur on time scales that are significantly longer than those accessible by direct simulations. One successful approach to estimating dynamical statistics for such processes is to use many short time series of observations of the system to construct a Markov state model, which approximates the dynamics of the system as memoryless transitions between a set of discrete states. The dynamical Galerkin approximation (DGA) is a closely related framework for estimating dynamical statistics, such as committors and mean first passage times, by approximating solutions to their equations with a projection onto a basis. Because the projected dynamics are generally not memoryless, the Markov approximation can result in significant systematic errors. Inspired by quasi-Markov state models, which employ the generalized master equation to encode memory resulting from the projection, we reformulate DGA to account for memory and analyze its performance on two systems: a two-dimensional triple well and the AIB9 peptide. We demonstrate that our method is robust to the choice of basis and can decrease the time series length required to obtain accurate kinetics by an order of magnitude.
Exploring photoexcited spin states for fullerene-derivatives based organic bulk heterojunction solar cells using magneto-photocurrent
Authors: Hu Jiaji , Kan Lixuan , Xie Yongchao , Zhu Xixiang , Yu Haomiao , Li Jinpeng , Zhang Fujun , Duan Wubiao , Wang Kai
Published: February 2024

Fullerene-derivatives based bulk heterojunctions hold an exceptionally important role on the roadmap of highly efficient organic solar cells (OSCs). In recent years, the utilization of the non-fused ring acceptors based OSCs has further improved photovoltaic power conversion efficiencies. Among these, one of the fundamental issues is to explore and to understand the spin-related polaron dissociation at charge transfer states because they act as the central unit for the photovoltaic action. It is also eagerly important to quantify some internal fields, such as hyperfine fields and the spin–orbit coupling. The aim of the work is to develop a method for unraveling the photoexcited spin states, particularly for the fullerene-derivative based OSC. Furthermore, it helps to elucidate a long-standing issue regarding the relatively high production of photocurrent for the P3HT:PC71BM system, which is indeed contrary to its counterpart the P3HT:PC61BM system. Their corresponding Jablonski diagrams have been determined in order to understand interior spin dynamics. The method of the study offers an alternative route for an understanding of device performance from the spin-related aspect.
Probability model for gas–liquid annular flow in dynamic equilibrium among the processes of atomization, deposition, breakup, and coalescence
Authors: Wang Yumiao , Zhang Ri , Liu Yong , Zhou Zhongwei , Yin Jifu
Published: February 2024

In this paper, an improved probability model is introduced to provide a more comprehensive prediction of annular flow. Unlike previous work, which did not consider atomization and deposition, as well as breakup and coalescence, simultaneously, the improved model integrates all four processes into its framework. The mechanisms of these processes are described in detail by the present model. When annular flow is fully developed, the four processes reach dynamic equilibrium. A numerical program is compiled based on the influence of the four processes on the droplets. Five important parameters, including the droplet-diameter probability density distribution, characteristic droplet diameters, entrainment ratio, liquid film thickness, and interfacial shear-stress coefficient, are calculated when the annular flow is in dynamic equilibrium. The validity and accuracy of the improved model are assessed by comparison with 377 cases from 12 experiments. For most cases used to validate the predicted droplet-diameter probability density distribution, the prediction curves closely match the experimental data. The mean absolute percentage errors (MAPEs) for the two experiments used to validate the predicted characteristic droplet diameters are 20.74% and 24.04%, respectively. Additionally, the mean MAPEs of the entrainment ratio, liquid film thickness, and interfacial shear-stress coefficient are found to be 34.11%, 20.60%, and 27.28%, respectively. This demonstrates the effectiveness and reliability of the improved probability model in predicting annular flow.
A simple fabrication of liquid-like polydimethylsiloxane coating for resisting ice adhesion
Authors: Zhang Yixuan , Wang Lei , Zhao Xueying , Yang Huige , Liu Jie , Wang Jianjun
Published: February 2024

The rapid realization of efficient anti-icing coatings on diverse substrates is of vital value for practical applications. However, current approaches for rapid preparations of anti-icing coatings are still deficient regarding their surface universality and accessibility. Here, we report a simple processing approach to rapidly form icephobic liquid-like polydimethylsiloxane (PDMS) brushes on various substrates, including metals, ceramics, glass, and plastics. A poly(dimethylsiloxane), trimethoxysilane is applied as a reactant under the catalysis of a minimal amount of acid formed by hydrolysis of dichlorodimethylsilane. With such an advantage, this approach is approved to be applicable of coating metal surfaces with less corrosion. The distinctive flexibility of the PDMS chains provides a liquid-like property to the coating showing low contact angle hysteresis and ice adhesion strength. Notably, the ice adhesion strength remains similar across a wide temperature window, from −70 to −10 °C, with a value of 18.4 kPa. The PDMS brushes demonstrate perfect capability for resisting acid and alkali corrosions, ultra-violet degradation, and even tens of icing/deicing cycles. Moreover, the liquid-like coating can also form at supercooling conditions, such as −20 °C, and shows an outstanding anti-icing/deicing performance, which meets the in situ coating reformation requirement under extreme conditions when it is damaged. This instantly forming anti-icing material will benefit from resisting instantaneous ice accretion on surfaces under extremely cold conditions.
Bubble generation mechanisms in microchannel under microgravity and heterogeneous wettability
Authors: Mousavi S. Mahmood , Lee Jongkwon , Lee Bok Jik , Jarrahbashi Dorrin , Karimi Nader , Faroughi Salah A.
Published: February 2024

Advances in hybrid surfaces have revealed interesting opportunities for multiphase flow control under microgravity, as the surface tension force is dominant in this condition. However, a comprehensive investigation of bubble generation rates and slug flow parameters remains challenging. This research integrates hybrid wettability and modified dynamic contact angle models to address this important knowledge gap. Using the computational capabilities of the IsoAdvector multiphase method, we performed detailed simulations of complex multiphase flow scenarios with the OpenFOAM package. We then validated these simulation results through rigorous comparison with available experimental data, thereby strengthening the accuracy and reliability of our numerical simulations. Our comprehensive research demonstrates the profound effect of altering contact angle distribution patterns on several critical parameters. These results highlight the precise control that can be achieved through the strategic manipulation of these patterns, offering the possibility of adjusting factors such as bubble production rate, slug length, bubble diameter, the relationship of flow residence to bubble movement, bubble movement speed in the channel, and pressure drop. Interestingly, altering these patterns can also induce asymmetric behavior in bubbles under microgravity conditions, a phenomenon that has significant implications for various applications. Such insights are crucial for fields such as heat transfer in energy systems, reaction mechanisms in chemical processes, multiphase flow control in petrochemical industries, fluid dynamics in aerospace engineering, and cooling mechanisms in electronic devices. With the ability to modulate these fundamental parameters, we gain valuable insights into the design and optimization of microchannel systems. Consequently, this research presents a more efficient and innovative approach to multiphase flow control, promising improved operational performance, and efficiency in various engineering applications.
A solver for subsonic flow around airfoils based on physics-informed neural networks and mesh transformation
Authors: Cao Wenbo , Song Jiahao , Zhang Weiwei
Published: February 2024

Physics-informed neural networks (PINNs) have recently become a new popular method for solving forward and inverse problems governed by partial differential equations. However, in the flow around airfoils, the fluid is greatly accelerated near the leading edge, resulting in a local sharper transition, which is difficult to capture by PINNs. Therefore, PINNs are still rarely used to solve the flow around airfoils. In this study, we combine physical-informed neural networks with mesh transformation, using a neural network to learn the flow in the uniform computational space instead of physical space. Mesh transformation avoids the network from capturing the local sharper transition and learning flow with internal boundary (wall boundary). We successfully solve inviscid flow and provide an open-source subsonic flow solver for arbitrary airfoils. Our results show that the solver exhibits higher-order attributes, achieving nearly an order of magnitude error reduction over second-order finite volume method (FVM) on very sparse meshes. Limited by the learning ability and optimization difficulties of the neural network, the accuracy of this solver will not improve significantly with mesh refinement. Nevertheless, it achieves comparable accuracy and efficiency to second-order FVM on fine meshes. Finally, we highlight the significant advantage of the solver in solving parametric problems, as it can efficiently obtain solutions in the continuous parameter space about the angle of attack.
Outcomes from water drop impact on hydrophobic meshes
Authors: Akbari Raziyeh , Wei Yu , Bagni Alberto , Ruffo Riccardo , Thoraval Marie-Jean , Chen Longquan , Antonini Carlo
Published: February 2024

Understanding water drop impact on meshes is valuable to design passive systems for atmospheric water collection. By investigating water drop impact on hydrophobic and superhydrophobic surfaces, here, we identify the different drop impact outcomes and build outcome maps within the pertinent parameter spaces, based on Weber number and contact angles. Furthermore, we quantitatively evaluate critical factors such as the captured volume and spray characteristics of the penetrating liquid and also measure the drop rebound time, reporting that full rebound occurs on superhydrophobic meshes surfaces even at high We numbers, as the Cassie–Baxter wetting state is maintained.
An improved porous media model for simulating the flow–nets interaction
Authors: Fan Zhongqi , Ma Chao , Xue Boru , Zhao Yunpeng , Liu Hangfei
Published: February 2024

This study presents an improved porous media model for simulating the interaction between the fixed aquaculture nets and flow. The fluid motion is computed based on the Reynolds time-averaged Navier–Stokes equations on the regular Eulerian mesh. The porous media model simulates the nets, where the interface between the complex shapes of the nets and the fluid is determined by the continuous forced immersed boundary (IB) method. The fluid volume fraction is defined and embedded in the porous media coefficients and porosity equations to set the porous media parameters at IB. Several cases validate the model, including the flow interactions with the single net panel, gravity net cage, and offshore aquaculture platform. Meanwhile, the effects of incoming velocity, attack angle, solidity, and the shape of the net on the simulation are investigated. The numerical model can reasonably predict the hydrodynamic of the nets with a relative error of less than 8%. Moreover, the computational efficiency of the hydrodynamic of complex shaped nets is significantly improved, with a maximum of about 11.54 times.
Wave-assisted propulsion: An experimental study on traveling ships
Authors: Chan ChunYin , Wang Junxian , Yang Liang , Zang Jun
Published: February 2024

A submerged hydrofoil interacting with incoming waves produces combined heaving and pitching motion, facilitating the conversion of wave energy into thrust. When the foil is attached to the ship hull, the generated “green” power from wave energy could assist the ship's propulsion system and significantly reduce fuel costs. This study experimentally assesses thrust generation from a fixed mid-hull foil by comparing towing force at different wave and traveling speeds. The optimal mid-hull foil demonstrates a fuel cost reduction ranging from 10.3% to 20.4% at diverse traveling speeds and wave parameters. Thrust generation increases at higher traveling speeds. Additionally, this study mathematically describes the hydrofoil motion with an outer pivot, which better suits the ship–foil model. This study then introduces a Strouhal number (StA,S) specifically for the ship–foil model, considering ship travel, ship response, and the hydrofoil's rotation around its outer pivot.
Two-phase electro-magneto-fluid dynamics model and its computational fluid dynamics implementation
Authors: Bošković Stefan A. , Bugarski Branko
Published: February 2024

In this work, we present a two-phase electro-magneto-fluid dynamics (EMFD) model that merges electromagnetics and fluid dynamics. The model is suitable for use in computational fluid dynamics (CFD) software and was incorporated into OpenFOAM® after deriving appropriate equations that bypassed certain limitations of the software. Currently, there is lack of even single-phase EMFD models that can be incorporated into CFD software; however, simpler models from electrohydrodynamics (EHD) and magnetohydrodynamics (MHD) are being implemented although they have certain approximations that can limit their applicability. We conclude that the derived EMFD model is applicable, and show its quality by implementing it and analyzing the results. We use cases with a droplet and the electrospinning process for verification. The drop deformations obtained were closer to analytical predictions than in the literature for two EHD models, but some oscillations were observed. We compared one simulation to the prediction of an analytical equation from MHD, and good agreement was shown. Finally, we simulate the electrospinning process, and the results were very close to the analytical predictions. We conclude that the implementation can be used for both EHD and MHD cases.
Influence of the suspension gap on the wake characteristics of a 600 km/h superconducting maglev train
Authors: Lin Tong Tong , Yang Ming Zhi , Zhang Lei , Wang Tian Tian , Liu Dong Run , Tao Yu , Zhong Sha
Published: February 2024

Although the suspension gap between a maglev train and its track is narrow, it has a significant impact on the aerodynamic performance of the train. This study investigated the effect of the suspension gap on the wake flow of a superconducting maglev train traveling at a speed of 600 km/h by comparing the aerodynamics and flow field structure of a tail car (TC) with suspension gaps of 8, 10, 12, and 14 cm. The results showed that with increasing suspension gap, the vortex structures in the wake region move closer to the TC, the airflow from the suspension gap inhibits the high-pressure region of the wake, and the pressure and velocity fluctuations significantly increase near the nose tip of the TC. Moreover, the suspension gap was found to have a significant impact on lift and almost no effect on drag. Increasing the suspension gap leads to a balance in the lift between the head car (HC) and the TC; as the gap continues to increase, the lift ratio of the HC and TC rapidly decreases.
Natural formation of linear defect structures in MoS2
Authors: Lukashev Pavel V. , Kidd Timothy E. , Harms Haley A. , Gorgen Colin , Stollenwerk Andrew J.
Published: February 2024

Near surface defects can significantly impact the quality of metallic interconnects and other interfaces necessary to create device structures incorporating two-dimensional materials. Furthermore, the impact of such defects can strongly depend on their organization. In this study, we present scanning tunneling microscopy images and tunneling spectroscopy of point and linear defects near the surface of natural MoS2. The point defects share similar structural and electronic characteristics and occur with comparable frequency as subsurface sulfur vacancies observed previously on natural MoS2. The linear defects observed here occur less frequently than the point defects but share the same depth profile and electronic structure. These data indicate that the linear defects are actually a one-dimensional organization of subsurface sulfur vacancies. Our density functional calculations agree with this assessment in that, for sufficient local defect concentrations, it is energetically more favorable for the defects to be organized in a linear fashion rather than as clusters or even isolated single point defects. Given these measurements were taken from naturally formed MoS2, this organization likely occurs during crystal formation. Considering the impact of one-dimensional organization on the local properties of layered materials, and the potential for them to be introduced purposefully during crystal formation, research into the formation mechanism and properties of these defects could enable new paths for defect engineering in MoS2-based systems.
The effect of small perturbation on dynamics of absorptive LiBr–water solution
Authors: Arroiabe P. F. , Martinez-Agirre M. , Nepomnyashchy A. , Bou-Ali M. M. , Shevtsova V.
Published: February 2024

In a binary solution of lithium bromide–water, even a small disturbance in the initial homogeneous mass fraction at the absorbing interface has profound effects on the entire system dynamics. This perturbation of absorption disrupts the equilibrium, leading to the formation of surface tension gradients and subsequently, Marangoni flows. While these flows are relatively weak, they result in a non-uniform distribution of density within the bulk, initiating buoyant convection. We investigate complexities of the Marangoni, solutal, and buoyant convection caused by localized disruptions in uniform absorption, all in the absence of any surfactants. We have conducted numerical simulations to explore fluid dynamics and heat and mass transfer, revealing three different regimes. Initially, shortly after disturbance, variations in mass fraction and flow within the cell are primarily governed by the Marangoni force. After a finite period, the emergence of buoyant convection leads to the strong growth of velocity and significant changes in temperature and mass fraction. Finally, the destabilization of the boundary layer becomes so significant that the emission of plumes is observed. At later times, the parallel existence of two types of patterns takes on a spatially fixed form. The central part, occupied by bands (visible on space-time maps), exhibits minimal changes in time, while a periodic structure is established near the wall. This behavior can be characterized as a relaxation–oscillation mode of instability.
Insight into the formation of slag eyes and the mechanism of slag entrapment in the steel-ladle refining process: Hydraulic modeling and numerical simulations
Authors: Lu Zhongyang , Tang Haiyan , Zhao Shuo , Wang Kaimin , Zhang Jiaquan
Published: February 2024

Slag eyes are the upper exposed areas of molten steel in a refining ladle that are formed due to excessive bottom argon bubbling. This phenomenon frequently occurs in the steel-refining process and can lead to slag entrapment and re-oxidation of molten steel. Taking a 150-t industrial steel ladle as the research object, the effects of a dual-plug gas-blown process on the slag-eye size were studied using hydraulic modeling and large-eddy simulations. The experimental results showed that at higher gas flow rates such as 9.1 and 11.7 normal liters/min (Nl/min), the relative central angle of the two porous plugs had a significant effect on the slag-eye size; conversely, at lower gas flow rates, its influence could be ignored. Due to the tendency of the two small slag eyes to merge, the 0.6R–45° (R being the bottom radius of the ladle) case resulted in a larger total slag-eye area compared to the cases with other angles. The 0.6R–135° case showed the most beneficial results for reducing the slag-eye size. Additionally, the numerical simulations helped us to visualize the bubble-uplifting and slag-eye formation processes, and they allowed an exploration of the slag-entrapment mechanism. The simulation results showed that the symmetric gas-blown mode can reduce slag entrapment when compared with the asymmetric mode for the 135°–11.7 Nl/min case; this will be favorable to control the cleanliness of the molten steel. Additionally, analysis of both liquid-level fluctuations and turbulent-kinetic-energy distributions further confirmed the advantages of the symmetric gas-blown mode for suppressing slag entrapment.
Thermo-capillarity of immiscible binary fluids within serpentine micro-confinements
Authors: Agrawal Shubham , Das Prasanta K. , Dhar Purbarun
Published: February 2024

The thermocapillary flow of multiple liquid layers over contoured substrates finds applications in many industrial phenomena via micro-electromechanical systems/nano-electromechanical systems devices. This study theoretically explores the thermocapillary transport of binary-liquid layers in a wavy microchannel with serpentine wall profiles. Sinusoidal profiles are considered for the microchannel walls' temperature and surface topology. Patterned slip conditions at the walls are also accounted for in the analysis to make the problem more realistic. We semi-analytically solve the energy and momentum equations to understand the system's thermal and hydrodynamic characteristics for the limiting conditions of Ma, Re, and Ca. The leading- and higher-order solutions of the temperature and flow field are separately shown to demonstrate the advection terms' contribution to the transport equations. The circulatory flow obtained due to periodic thermal stimuli can be used to enhance the mixing efficiency of the system. We also present how the parameters like phase difference between the thermal stimulus, relative thermal conductivity, and relative film thickness ratio of the liquid layers can be altered to control the flow characteristics to obtain the most potent thermocapillary effect.
Magnetic interactions in vortex-state nanodisk arrays characterized by gradient magnetic vortex echo
Authors: Vigo-Cotrina H. , Urcia-Romero S. , P. Guimarães A.
Published: February 2024

Magnetic vortices have potential applications in the field of spintronics and medicine and studying their magnetic interactions is crucial for future applications. This work introduces a new method based on obtaining the gradient magnetic vortex echo (GMVE) using micromagnetic simulations following a magnetic resonance imaging protocol. The results show that it is possible to characterize the magnetic interaction of arrays of nanodisks, having equal diameter and vortex configuration, as a function of disk separation. This characterization was performed by creating an inhomogeneity in the system through the application of a magnetic field gradient perpendicular to the plane of the nanodisk array. The inhomogeneity allows refocusing the magnetization in a time-controlled way by inverting the sign of the gradient and obtaining the characteristic transverse relaxation time T2∗ from the GMVE that contains the information on the magnetic interaction.
Adiabatic ionization energies of RuC, RhC, OsC, IrC, and PtC
Authors: Merriles Dakota M. , Barrera-Casas Yexalen , Knapp Annie S. , Morse Michael D.
Published: February 2024

The ionization energies (IEs) of RuC, RhC, OsC, IrC, and PtC are assigned by the measurement of their two-photon ionization thresholds. Although late transition metal–carbon bonds are of major importance in organometallic chemistry and catalysis, accurate and precise fundamental thermochemical data on these chemical bonds are mainly lacking in the literature. Based on their two-photon ionization thresholds, in this work, we assign IE(RuC) = 7.439(40) eV, IE(RhC) = 7.458(32) eV, IE(OsC) = 8.647(25) eV, IE(IrC) = 8.933(74) eV, and IE(PtC) = 9.397(32) eV. These experimentally derived IEs are further confirmed through quantum chemical calculations using coupled-cluster single double perturbative triple methods that are extrapolated to the complete basis set limit using a three-parameter mixed Gaussian/exponential extrapolation scheme and corrected for spin–orbit effects using a semiempirical method. The electronic structure and chemical bonding of these MC species are discussed in the context of these ionization energy measurements. The IEs of RuC, RhC, OsC, and IrC closely mirror the IEs of the corresponding transition metal atoms, suggesting that for these species, the (n + 1)s electrons of the transition metals are not significantly involved in chemical bonding.
Controllable transformed waves of a (3 + 1)-dimensional variable-coefficient Kadomtsev–Petviashvili equation in fluids or plasma
Authors: Yao Xuemin , Han Rong , Wang Lei
Published: February 2024

In this paper, we study the modulations of nonlinear transformed waves for a (3 + 1)-dimensional variable-coefficient Kadomtsev–Petviashvili equation in fluids or plasma. By virtue of the phase shift analysis, the shape-changed and unchanged transformed waves are investigated, which shows the inhomogeneity can restrain the time-varying property. The deformation of waves is determined by the phase difference between two wave components. In addition, the evolutions of parabolic transformed waves are illustrated via characteristic lines analysis. The interactions are further explored, which involve the long- and short-lived collisions. In particular, we discuss the dynamics of unidirectional and reciprocating molecular waves based on the velocity resonance condition, including the shape-changed and unchanged atoms. Different from previous results, certain new types of transformed molecular waves with shape-unchanged atoms are discovered. Our results indicate that the inhomogeneity can produce novel transformed waves and further facilitate the modulation of phase transition mechanism.
Promoting the carrier mobility of Nb2SiTe4 through cation coordination engineering
Authors: Meng Weiwei , Nie Zhiguo , Lin Long , Huang Li , Yin Hao , Guo Yuhan , Qian Jijun , Shi Tingting , Hong Feng , Long Mingzhu
Published: February 2024

Ternary two-dimensional (2D) monoclinic Nb2SiTe4 has garnered significant attention for its potential applications in anisotropic photoelectronics. Yet, its intrinsic indirect bandgap nature and low hole mobility, attributed to the short Nb–Nb dimer configurations, hinder the efficient photogenerated carrier separation and transport. In this Letter, using density functional theory calculations, we demonstrate the interlayer intercalation of Si results in the formation of a metastable orthorhombic Nb2SiTe4 structure devoid of detrimental short Nb–Nb dimers. Notably, this Si intercalation leads to a remarkable reduction of hole effective masses of orthorhombic Nb2SiX4 (X = S, Se, and Te), a crucial factor for achieving high carrier mobility. Taking the orthorhombic Nb2SiTe4 monolayer as an example, the calculated hole mobility (>100 cm2 V−1 s−1) is comparable in magnitude to the respectable hole mobility observed in multiple layers of the monoclinic Nb2SiTe4. To simultaneously enhance electron and hole mobility, we establish a van der Waals junction between the monoclinic and orthorhombic Nb2SiTe4 structures, achieving high and comparable carrier mobilities. The Nb2SiTe4 junction exhibits a nearly direct bandgap of 0.35 eV, rendering it suitable for infrared light harvesting. Furthermore, carriers within the Nb2SiTe4 junction become spatially separated across different layers, resulting in an intrinsic built-in electric field, which is superior for efficient photo-generated charge separation and decreases the potential nonradiative carrier recombination. Our findings highlight the impact of cation coordination engineering on the electronic and optical properties of 2D Nb2SiTe4 and provide a feasible solution to achieve better carrier transport in low-dimensional photovoltaic functionalities.
Spin glass state in Co doped NdMnO3
Authors: Bhat Farooq Hussain , Anjum Ghazala
Published: February 2024

The temperature-dependent ac susceptibility studies of in-phase component (χ′ac) and out of phase component (χac″) was done on a single phase polycrystalline NdMn0.6Co0.4O3 sample. The measurements were conducted in 4 Oe ac field and 0 Oe dc field at frequencies of 111, 311, 1011, and 1311 Hz. As the frequency increases, the magnitude of χ′ac decreases, and its peak position, corresponding to Tf, moves towards higher temperatures. This strongly suggests the presence of a spin glass (SG) state and the absence of long-range ferromagnetic ordering. The value of relative shift in freezing temperature (δTf) is found to be δTf = 0.0089, which suggests the existence of canonical SG state in NdMn0.6Co0.4O3 sample. To confirm it the ac susceptibility data was further analyzed using Arrhenius, Vogel Fulcher, and Power–law.
Differential effects of elevated CO2 on awn and glume metabolism in durum wheat (Triticum durum)
Authors: Tcherkez Guillaume , Ben Mariem Sinda , Jauregui Iván , Larraya Luis , García-Mina Jose M. , Zamarreño Angel M. , Fangmeier Andreas , Aranjuelo Iker
Published: February 2024

While the effect of CO2 enrichment on wheat (Triticum spp.) photosynthesis, nitrogen content or yield has been well-studied, the impact of elevated CO2 on metabolic pathways in organs other than leaves is poorly documented. In particular, glumes and awns, which may refix CO2 respired by developing grains and be naturally exposed to higher-than-ambient CO2 mole fraction, could show specific responses to elevated CO2. Here, we took advantage of a free-air CO2 enrichment experiment and performed multilevel analyses, including metabolomics, ionomics, proteomics, major hormones and isotopes in Triticum durum. While in leaves, elevated CO2 tended to accelerate amino acid metabolism with many significantly affected metabolites, the effect on glumes and awns metabolites was modest. There was a lower content in compounds of the polyamine pathway (along with uracile and allantoin) under elevated CO2, suggesting a change in secondary N metabolism. Also, cytokinin metabolism appeared to be significantly affected under elevated CO2. Despite this, elevated CO2 did not affect the final composition of awn and glume organic matter, with the same content in carbon, nitrogen and other elements. We conclude that elevated CO2 mostly impacts on leaf metabolism but has little effect in awns and glumes, including their composition at maturity.
IL-27 regulates the differentiation of follicular helper NKT cells via metabolic adaptation of mitochondria
Authors: Kamii Yasuhiro , Hayashizaki Koji , Kanno Toshio , Chiba Akio , Ikegami Taku , Saito Mitsuru , Akeda Yukihiro , Ohteki Toshiaki , Kubo Masato , Yoshida Kiyotsugu , Kawakami Kazuyoshi , Oishi Kazunori , Araya Jun , Kuwano Kazuyoshi , Kronenberg Mitchell , Endo Yusuke , Kinjo Yuki
Published: February 2024

Invariant natural killer T (iNKT) cells are innate-like T lymphocytes that express an invariant T cell receptor α chain and contribute to bridging innate and acquired immunity with rapid production of large amounts of cytokines after stimulation. Among effecter subsets of iNKT cells, follicular helper NKT (NKTFH) cells are specialized to help B cells. However, the mechanisms of NKTFHcell differentiation remain to be elucidated. In this report, we studied the mechanism of NKTFHcell differentiation induced by pneumococcal surface protein A and α-galactosylceramide (P/A) vaccination. We found that Gr-1+cells helped iNKT cell proliferation and NKTFHcell differentiation in the spleen by producing interleukin-27 (IL-27) in the early phase after vaccination. The neutralization of IL-27 impaired NKTFHcell differentiation, which resulted in compromised antibody production and diminished protection againstStreptococcus pneumoniaeinfection by the P/A vaccine. Our data indicated that Gr-1+cell–derived IL-27 stimulated mitochondrial metabolism, meeting the energic demand required for iNKT cells to differentiate into NKTFHcells. Interestingly, Gr-1+cell–derived IL-27 was induced by iNKT cells via interferon-γ production. Collectively, our findings suggest that optimizing the metabolism of iNKT cells was essential for acquiring specific effector functions, and they provide beneficial knowledge on iNKT cell–mediated vaccination-mediated therapeutic strategies.
Rita Colwell: Use your voice to bring about positive change
Authors: Van Emmenis Lucie
Published: February 2024

Rita Colwell is a Distinguished University Professor at the University of Maryland at College Park and at Johns Hopkins University Bloomberg School of Public Health, senior advisor and chairman emeritus at Canon US Life Sciences, Inc., founder and chairman of CosmosID, Inc., and president of the Rosalind Franklin Society. She has authored or co-authored 20 books and more than 800 scientific publications, and throughout her career has focused on improving health outcomes across the world and highlighting the impacts of infectious diseases in drinking/bathing water. We recently spoke to Rita about her career and her thoughts about the future for women in science.
Sub-wavelength topological boundary states and rainbow trapping of local-resonance phononic crystal plate
Authors: Sun Xiao-Wei , Tan Mao-Ting , Xu Gang-Gang , Cao Yue , Wen Xiao-Dong , Liu Zi-Jiang
Published: February 2024

Based on the analogy of the quantum valley Hall effect, a ligament-type phononic crystal plate with local resonators is designed in this study to facilitate the valley state transport of low-frequency elastic waves. We analyze the key factors affecting the local resonance modes and reduce the frequency of the Dirac cone by changing the connection form of the structure’s beams. The spatial inversion symmetry of the structure is broken to open a new band gap by introducing a mass difference in the resonator pair. The robustness of the designed structure’s topological valley waveguide under defects and bends is verified. Based on this characteristic, we introduce the gradient heights into the supercell structure where elastic waves at different frequencies split and stop significantly on the supercell structure to achieve sub-wavelength topological rainbow trapping. This design provides a theoretical reference for exploring the low-frequency elastic topological mode and the application of topological rainbow capture in sub-wavelength structures.
Dynamic calibration method for track geometry measurement system-a case study in China
Authors: Han Zhi , Han Lei , Chen Chunlei , Han Qiang , Jing Guoqing , Cheng Zhaoyang
Published: February 2024

With the rapid development of railway construction, the mileage of railway detection has increased dramatically, and railway companies have higher requirements for the repeatability and accuracy of track geometric dynamic detection data. Therefore, the track geometry measurement system needs to be calibrated to improve the measurement accuracy to ensure the safety of railway operation. However, the existing calibration methods of the track geometry measurement system can only realize the static calibration and lack the dynamic calibration method, which cannot calibrate the track geometry measurement system under the real operation state. Therefore, a dynamic calibration method for the track geometry measurement system is proposed in this paper. A real and reliable test environment is provided for the track geometry measurement system by presetting the track geometry irregularity and laying the rail dynamic displacement monitoring system on the calibration test line, and the dynamic and static differences of the track are analyzed based on the test environment. Based on the bisection method, this paper reduces the measurement error of the track geometry measurement system and analyzes the measurement repeatability of the track geometry measurement system. Finally, the error correction model of the track geometry measurement system is established, and the error analysis and uncertainty evaluation of the track geometry measurement system are carried out. The results show that the track geometry measurement system calibrated by the dynamic calibration method proposed in this paper meets the requirements of the measurement error for the gauge and cross level. This study can establish the value traceability relationship of the track geometry measurement system, realize the calibration and evaluation of the accuracy of the track geometry measurement system under the real operation state, and improve the reliability and accuracy of the track geometry dynamic detection results.