bluuebunny/crossref_metadata_2025 huggingface dataset:
MW‐SAM:Mangrove wetland remote sensing image segmentation network based on segment anything model
Authors: Zhang Yu , Wang Xin , Cai Jingye , Yang Qun
Published: October 2024

Mangrove wetlands are important ecosystems in tropical and subtropical coastal areas, providing wind and wave attenuation and embankment protection functions. However, mangrove wetlands worldwide are facing severe loss and degradation. Accurate identification of mangrove wetland extent is crucial for their protection, but traditional methods struggle to meet the requirements of large‐scale, high‐precision identification. Furthermore, field data collection and annotation in wetlands in complex intertidal zones pose challenges, and the lack of high‐quality training samples limits the application of deep learning methods in this field. This paper proposes a novel semantic segmentation framework for mangrove wetlands called mangrove wetland remote sensing image segmentation network based on segment anything model (MW‐SAM) to address these issues. MW‐SAM is based on the pre‐trained SAM and achieves cross‐domain adaptation through parameter‐efficient fine‐tuning techniques. It introduces wetland‐specific prompts, auxiliary branches, semi‐supervised training, and iterative optimization strategies to improve accuracy and tackle the problem of sample scarcity. Moreover, on the mangrove wetland dataset constructed in this paper, MW‐SAM significantly outperforms SAM and other traditional methods. MW‐SAM provides a new technology for monitoring and protecting mangrove wetlands, and the constructed dataset will be made publicly available, which is expected to promote the development of mangrove wetland conservation efforts.
Pulsar-wind nebulae meeting the circumstellar media of their progenitors
Authors: Meyer D. M.-A. , Meliani Z. , Torres D. F.
Published: October 2024

Context. A significative fraction of high-mass stars sail away through the interstellar medium of the galaxies. Once they evolved and died via a core-collapse supernova, a magnetised, rotating neutron star (a pulsar) is usually left over. The immediate surroundings of the pulsar is the pulsar wind, which forms a nebula whose morphology is shaped by the supernova ejecta and channelled into the circumstellar medium of the progenitor star in the pre-supernova time.

Aims. Irregular pulsar-wind nebulae display a large variety of radio appearances, screened by their interacting supernova blast wave, or harbour asymmetric up–down emission.

Methods. Here, we present a series of 2.5-dimensional (2 dimensions for the scalar quantities plus a toroidal component for the vectors) non-relativistic magneto-hydrodynamical simulations exploring the evolution of the pulsar-wind nebulae generated by a red supergiant and a Wolf-Rayet massive supernova progenitor, moving with Mach number M = 1 and M = 2 into the warm phase of the Galactic plane. In such a simplified approach, the progenitor’s direction of motion, the local ambient medium magnetic field, and the progenitor and pulsar axis of rotation, are all aligned; this restricted our study to peculiar pulsar-wind nebula of high-equatorial-energy flux.

Results. We find that the reverberation of the termination shock of the pulsar-wind nebulae, when sufficiently embedded into its dead stellar surroundings and interacting with the supernova ejecta, is asymmetric and differs greatly as a function of the past circumstellar evolution of its progenitor, which reflects into their projected radio synchrotron emission. This mechanism is particularly at work in the context of remnants involving slowly moving or very massive stars.

Conclusions. We find that the mixing of material in plerionic core-collapse supernova remnants is strongly affected by the asymmetric reverberation in their pulsar-wind nebulae.
Evidence for a shock-compressed magnetic field in the northwestern rim of Vela Jr. from X-ray polarimetry
Authors: Prokhorov Dmitry A. , Yang Yi-Jung , Ferrazzoli Riccardo , Vink Jacco , Slane Patrick , Costa Enrico , Silvestri Stefano , Zhou Ping , Bucciantini Niccolò , Di Marco Alessandro , Weisskopf Martin C. , Baldini Luca , Doroshenko Victor , Ehlert Steven R. , Heyl Jeremy , Kaaret Philip , Kim Dawoon E. , Marin Frédéric , Mizuno Tsunefumi , Ng Chi-Yung , Pesce-Rollins Melissa , Sgrò Carmelo , Soffitta Paolo , Swartz Douglas A. , Tamagawa Toru , Xie Fei , Agudo Iván , Antonelli Lucio A. , Bachetti Matteo , Baumgartner Wayne H. , Bellazzini Ronaldo , Bianchi Stefano , Bongiorno Stephen D. , Bonino Raffaella , Brez Alessandro , Capitanio Fiamma , Castellano Simone , Cavazzuti Elisabetta , Chen Chien-Ting , Ciprini Stefano , De Rosa Alessandra , Del Monte Ettore , Di Gesu Laura , Di Lalla Niccolò , Donnarumma Immacolata , Dovčiak Michal , Enoto Teruaki , Evangelista Yuri , Fabiani Sergio , García Javier A. , Gunji Shuichi , Iwakiri Wataru , Jorstad Svetlana G. , Karas Vladimir , Kislat Fabian , Kitaguchi Takao , Kolodziejczak Jeffery J. , Krawczynski Henric , La Monaca Fabio , Latronico Luca , Liodakis Ioannis , Maldera Simone , Manfreda Alberto , Marinucci Andrea , Marscher Alan P. , Marshall Herman L. , Massaro Francesco , Matt Giorgio , Mitsuishi Ikuyuki , Muleri Fabio , Negro Michela , O’Dell Stephen L. , Omodei Nicola , Oppedisano Chiara , Papitto Alessandro , Pavlov George G. , Peirson Abel L. , Perri Matteo , Petrucci Pierre-Olivier , Pilia Maura , Possenti Andrea , Poutanen Juri , Puccetti Simonetta , Ramsey Brian D. , Rankin John , Ratheesh Ajay , Roberts Oliver J. , Romani Roger W. , Spandre Gloria , Tavecchio Fabrizio , Taverna Roberto , Tawara Yuzuru , Tennant Allyn F. , Thomas Nicholas E. , Tombesi Francesco , Trois Alessio , Tsygankov Sergey S. , Turolla Roberto , Wu Kinwah , Zane Silvia
Published: October 2024

Synchrotron X-ray emission has been detected from nearly a dozen young supernova remnants (SNRs). X-rays of synchrotron origin exhibit linear polarization in a regular, non-randomly oriented magnetic field. The significant polarized X-ray emission from four such SNRs has already been reported on the basis of observations with the Imaging X-ray Polarimetry Explorer (IXPE). The magnetic-field structure as derived from IXPE observations is radial for Cassiopeia A, Tycho’s SNR, and SN 1006, and tangential for RX J1713.7−3946. The latter together with the recent detection of a tangential magnetic field in SNR 1E 0102.2-7219 by the Australia Telescope Compact Array in the radio band shows that tangential magnetic fields can also be present in young SNRs. Thus, the dichotomy in polarization between young and middle-aged SNRs (radial magnetic fields in young SNRs, but tangential magnetic fields in middle-aged SNRs), previously noticed in the radio band, deserves additional attention. The present analysis of IXPE observations determines, for the first time, a magnetic-field structure in the northwestern rim of Vela Jr, also known as RX J0852.0−4622, and provides a new example of a young SNR with a tangential magnetic field.
A hybrid finite element method for moving-habitat models in two spatial dimensions
Authors: MacDonald Jane Shaw , Bourgault Yves , Lutscher Frithjof
Published: October 2024

Moving-habitat models track the density of a population whose suitable habitat shifts as a consequence of climate change. Whereas most previous studies in this area consider 1-dimensional space, we derive and study a spatially 2-dimensional moving-habitat model via reaction-diffusion equations. The population inhabits the whole space. The suitable habitat is a bounded region where population growth is positive; the unbounded complement of its closure is unsuitable with negative growth. The interface between the two habitat types moves, depicting the movement of the suitable habitat poleward. Detailed modelling of individual movement behaviour induces a nonstandard discontinuity in the density across the interface. For the corresponding semi-discretised system we prove well-posedness for a constant shifting velocity before constructing an implicit-explicit hybrid finite element method. In this method, a Lagrange multiplier weakly imposes the jump discontinuity across the interface. For a stationary interface, we derive optimal a priori error estimates over a conformal mesh with nonconformal discretisation. We demonstrate with numerical convergence tests that these results hold for the moving interface. Finally, we demonstrate the strength of our hybrid finite element method with two biologically motivated cases, one for a domain with a curved boundary and the other for non-constant shifting velocity.
Growth mechanism of Al2O3 on surface of ZrO2 inclusions: experimental and first principles investigation
Authors: Li Xiang , Bao Yanping , Wang Jun , Li Yutang , Wang Linzhu
Published: October 2024

Zr has been widely used in high-quality steel due to its strong deoxidizing capacity and ability of improve performance of steel. ZrO2–Al2O3 inclusions with core-shell structure were observed in this study. The structure, electronic properties, and energy changes of ZrO2 and ZrO2–Al2O3 systems were studied based on first principles calculation. It indicates that ZrO2 can be used as the heterogeneous nucleation core of Al2O3. Al atoms were preferentially adsorbed on the bridge site of ZrO2 (001) and then form the ZrO2–Al2O3 interface. The template effect of ZrO2 was nine adsorption atomic layers, among which layers 1–5 was a coherent epitaxial layer, layers 5–9 was the transition layer, and the atomic ratio was 3:2. The growth mechanism of Al2O3 on ZrO2 surface was discussed. The results help understand the formation of inclusion at atomic scale and find ways to control the characteristics of inclusion in steel with Zr treatment.
Minimal wave speed for a two-group epidemic model with nonlocal dispersal and spatial-temporal delay
Authors: Han Jiawen , Xu Rui
Published: October 2024

In this paper, a two-group SIR reaction-diffusion epidemic model with nonlocal dispersal and spatial-temporal delay based on within-group and inter-group transmission mechanisms is investigated. The basic reproduction number R0 is calculated using the method of next-generation matrix. The critical wave speed cm* is determined by analyzing the distribution of roots of the characteristic equation. When R0>1 and wave speed c⩾cm*, the existence of traveling waves connecting disease-free and endemic steady states is obtained by constructing sub- and super-solutions and a Lyapunov functional, and applying Schauder’s fixed-point theorem and a limit argument. When R0>1 and 0<c<cm*, the nonexistence of traveling waves connecting disease-free and endemic steady states is proven by contradiction and two-sided Laplace transform. This indicates that the critical wave speed cm* is exactly the minimum wave speed. Numerical simulations are carried out to illustrate theoretical results. The dependence of the minimal speed cm* on time delay, diffusion rates and contact rates is discussed, showing that the longer the latent period and the lower the diffusion rates of infected individuals and the inter-group transmission rates between groups, the slower the spread of disease.
Prediction of carotid artery plaque area based on parallel multi-gate attention capture model
Authors: Hu Jiangbo , Li Feng , Xu Hongzeng , Zang Peizhuo , Cao Xingbing , Mao Xiawei , Gao Fei
Published: October 2024

Cardiovascular disease (CVD) is a group of conditions involving the heart or blood vessels and is a leading cause of death and disability worldwide. Carotid artery plaque, as a key risk factor, is crucial for the early prevention and management of CVD. The purpose of this study is to combine clinical application and deep learning techniques to design a predictive model for the carotid artery plaque area. This model aims to identify individuals at high risk and reduce the incidence of cardiovascular disease through the implementation of relevant preventive measures. This study proposes an innovative multi-gate attention capture (MGAC) model that utilizes data such as risk factors, laboratory tests, and physical examinations to predict the area of carotid artery plaque. Experimental findings reveal the superior performance of the MGAC model, surpassing other commonly used deep learning models with the following metrics: mean absolute error of 4.17, root mean square error of 10.89, mean logarithmic squared error of 0.21, and coefficient of determination of 0.98.
Quantitative suppression of unsteady powerline noise in transient electromagnetic surveys: Adjustment of base-frequency and optimal choice of stacking-times
Authors: Jang Choljin , Sin Okchol , Jon Gwangbok
Published: October 2024

Powerline noise is a severe interference source in urban or mine transient electromagnetic (TEM) surveys. TEM systems generally adopt the synchronous detection scheme to suppress the powerline noise. However, when the powerline frequency fluctuates differing from its nominal value (50/60 Hz), the considerable powerline noise residue still remains even after synchronous detection. To overcome this problem, this paper proposes the quantitative suppression method for powerline noise taking into account the instability of powerline frequency. The method is based on the adjustment of base-frequency and optimal choice of stacking-times. We represent mathematically the sufficient condition for powerline noise suppression by synchronous detection. It consists of two equations, one with respect to base-frequency and other with respect to stacking-times. The base-frequency is adjusted according to powerline frequency estimate. We first derive the mathematical relationship between frequency estimation accuracy, residual noise amplitude, and stacking-times. Based on it, we develop an efficient algorithm to determine the optimal stacking-times. The algorithm takes as an input the powerline noise estimates and the noise tolerance limit. The tolerance limit is set to a certain value desired by the user, such as 10, 4, and 1 µV. By adjusting base-frequency and determining optimal stacking-times, the powerline noise residue after synchronous detection is reduced to below the desired tolerance limit. We verify the effectiveness of the proposed method for both simulated and actual noise. Experimental results show that the method achieves quantitative suppression of unsteady powerline noise without any damage of effective signal and prevents the measurement time loss due to excessive stacking.
Improved wind resource modeling using bimodal Weibull distribution
Authors: Aldaoudeyeh Al-Motasem
Published: October 2024

Despite the common norm of modeling wind regimes using two-parameter Weibull distribution (2WD), this probability density function (PDF) is not suitable for sites of calm wind regime. Furthermore, 2WD PDF lacks bimodality and exhibits a quasi-flat shape, which are phenomena seen occasionally in some sites. In this paper, the application of bimodal Weibull distribution (BWD) is proposed as a more comprehensive alternative to the conventional 2WD. A comparative analysis of BWD with 2WD, five-parameter Weibull and Weibull distribution, and three-parameter generalized extreme value distribution, across 32 sites spanning all five continents, reveals moderate to substantial improvements in root mean square error, χ2 statistic, and R2. In addition, the paper demonstrates and explores distinct attributes of BWD, such as bimodality, quasi-flat shapes, flat-start, and others.
Atomistic first-principles modeling of single donor spin-qubit
Authors: Jia Songqi , Beaudoin Félix , Philippopoulos Pericles , Guo Hong
Published: October 2024

Using an impurity atom in crystal silicon as a spin-1/2 qubit has been made experimentally possible recently where the impurity atom acts as a quantum dot (QD). Quantum transport in and out of such a donor QD occurs in the sequential tunneling regime where a physical quantity of importance is the charging (addition) energy, which measures the energy necessary for adding an electron into the donor QD. In this work, we present a first-principles method to quantitatively predict the addition energy of the donor QD. Using density functional theory (DFT), we determine the impurity states that serve as the basis set for subsequent exact diagonalization calculation of the many-body states and energies of the donor QD. Due to the large effective Bohr radius of the conduction electrons in Si, very large supercells containing more than 10 000 atoms must be used to obtain accurate results. For the donor QD of a phosphorus impurity in bulk Si, the combined DFT and exact diagonalization predicts the first addition energy to be 53 meV, in good agreement with the corresponding experimental value. For the donor QD of an arsenic impurity in Si, the first addition energy is predicted to be 44.2 meV. The calculated many-body wave functions provide a vivid electronic picture of the donor QD.
Scanning tunneling microscopy of ultrathin indium intercalated between graphene and SiC using confinement heteroepitaxy
Authors: Pham Van Dong , González César , Dappe Yannick J. , Dong Chengye , Robinson Joshua A. , Trampert Achim , Engel-Herbert Roman
Published: October 2024

Large-scale and air-stable two-dimensional metal layers intercalated at the interface between epitaxial graphene and SiC offer an appealing material for quantum technology. The atomic and electronic details, as well as the control of the intercalated metals within the interface, however, remain very limited. In this Letter, we explored ultrathin indium confined between graphene and SiC using cryogenic scanning tunneling microscopy, complemented by first-principle density functional theory. Bias-dependent imaging and tunneling spectroscopy visualize a triangular superstructure with a periodicity of 14.7 ± 3 Å and an occupied state at about −1.6 eV, indicating proof of highly crystalline indium. The scanning tunneling microscopy tip was used to manipulate the number of indium layers below graphene, allowing to identify three monatomic In layers and to tune their corresponding electronic properties with atomic precision. This further allows us to attribute the observed triangular superstructure to be solely emerging from the In trilayer, tentatively explained by the lattice mismatch induced by lattice relaxation in the topmost In layer. Our findings provide a microscopic insight into the structure and electronic properties of intercalated metals within the graphene/SiC interface and a unique possibility to manipulate them with atomic precision using the scanning probe technique.
Two independent mechanisms with distinct laws for the generation of drag force on accelerating plates
Authors: Li Zhuoqi , Chen Lunbing , Xiang Yang , Liu Hong , Wang Fuxin
Published: October 2024

Acceleration of objects in fluids widely exists in biological propulsions and contains rich unsteady fluid mechanisms. In this paper, the instantaneous drag force on accelerating normal flat plates (circular, elliptical, square, and rectangular plates) in a wide range of dimensionless acceleration (a*=16∼2) is measured, and the underlying mechanism for force generation is investigated. At first, we find that the drag force coefficient generally scales with the square root of a* when a*<1.0, coinciding with the scaling law given by Reijtenbagh et al. (PRL. 2023,130,174001). However, the drag force coefficient more linearly scales with a* rather than a* when a*>1.0, thereby indicating acceleration plays two distinct roles on the force generation depending on a*. Moreover, two scaling laws are built to quantitatively describe the two distinct roles of a* on the drag force generation. Based on fluid impulse, the drag force is largely contributed by the added mass of the accelerating plates (added mass force) and vorticity generation fed by the shear layer on the edge of the plates (vortex creation force). When a*<1.0, the vortex creation force scales with a* and almost contributes to the total drag force. When a*>1.0, the added mass force scaling with a* contributes to most of the drag force. Furthermore, the two force generation mechanisms associated with acceleration (a*) are independent, and a criterion based on the energy ratio is proposed to identify the transition of the two force generation mechanisms. The present results uncover the role of acceleration in force generation and explain the inconsistencies of using one quasi-steady model in describing the force on accelerating plates.
Angular anisotropy of hard x rays produced by laboratory atmospheric discharges
Authors: Parkevich E. V. , Shpakov K. V. , Baidin I. S. , Rodionov A. A. , Khirianova A. I. , Bolotov Ya. K. , Ryabov V. A.
Published: October 2024

The temporal, spectral, and angular characteristics of the x-ray emissions (photons with energies within 5–1000 keV) are exhaustively investigated during the discharge formation at voltages up to 1 MV in approximately 55 cm air gaps. The temporal correlations between the x-ray emissions and discharge voltage and current waveforms are established. The evolution of the discharge plasma structures developing in the time periods of the x-ray generation is traced with a nanosecond resolution. Based on statistical data, theoretical analysis, and estimates the regularities in the x-ray emission characteristics are revealed together with their relationship with the ionization processes occurring in the gas-discharge medium. On the basis of the obtained experimental data, the probable x-ray generation mechanisms are discussed. The findings can provide a deeper understanding of the physics behind the sources of hard x rays arising during the development of laboratory and atmospheric discharges.
High-coherence quantum acoustics with planar superconducting qubits
Authors: Franse W. J. M. , Potts C. A. , Bittencourt V. A. S. V. , Metelmann A. , Steele G. A.
Published: October 2024

Quantum acoustics is an emerging platform for hybrid quantum technologies enabling quantum coherent control of mechanical vibrations. High-overtone bulk acoustic resonators (HBARs) represent an attractive mechanical implementation of quantum acoustics due to their potential for exceptionally high mechanical coherence. Here, we demonstrate an implementation of high-coherence HBAR quantum acoustics integrated with a planar superconducting qubit architecture, demonstrating an acoustically induced-transparency regime of high cooperativity and weak coupling, analogous to the electrically induced transparency in atomic physics. Demonstrating high-coherence quantum acoustics with planar superconducting devices enables interesting applications for acoustic resonators in quantum technologies.
Estimation of the friction coefficient by identifying the evolution of rough surface topography
Authors: Huang Dafei , Ta Wurui , Zhou Youhe
Published: October 2024

The complexity and randomness of surface roughness make the origin of friction always puzzling. Is there a potential correlation mechanism between the evolution of friction force and surface topography, and is it possible to estimate the friction coefficient from the topography evolution? Here, we explore the evolution of surface topography in metallic materials during friction by defining the characteristic orientation of the surface and analyzing its changes over time, which closely mirrors the behavior of friction forces. Then, we propose a simple relationship that relates the characteristic orientation and friction force via the friction coefficient. Therefore, the friction coefficient can be evaluated based on topography evolution without relying on any theoretical modeling assumptions. These results reveal the mechanism between complex surface topography and friction force through a simple formula and provide a method to estimate the friction coefficient. This method has promising applications when the friction coefficient is difficult to measure, such as in large-scale landslides and geologic faults.
Influences of blockage ratio and Reynolds number on the spatiotemporal dynamics around a rectangular prism
Authors: Abdul-Salam Fati Bio , Fang Xingjun , Tachie Mark Francis
Published: October 2024

Particle image velocimetry is used to experimentally investigate the influence of blockage ratio (BR) and Reynolds number (Re) on the turbulent flow around a rectangular prism with depth-to thickness ratio of 3. The prism was selected because it falls within the intermediate regime where the turbulent dynamics is sensitive to the incoming boundary condition. The tested blockage ratios were 2.5%, 5%, and 10% at Reynold numbers of 3000 and 7500. The results are analyzed in terms of the mean flow, turbulent kinetic energy (TKE), frequency spectra, reverse flow area, as well as spectral proper orthogonal decomposition (SPOD). The results indicate that as blockage ratio and/or Reynolds number increase, the tendency of reattachment of the separated shear layer onto the surface of the prism increases while the location of maximum TKE over the prism shifts toward the leading edge, indicating earlier transition of the separated shear layer from laminar to turbulence. For the cases without mean reattachment over the side faces of the prisms, the separated bubble over and downstream of the prism exhibits strong tendency of synchronization in terms of the instantaneous areas of the flow reversal, suggesting a global instability mechanism encompassing the entire prism. In cases with mean flow reattachment, conversely, the low-frequency flapping motion manifests over the prism. SPOD analysis further shows that the relevant shedding dynamics are captured in the first mode and the von Kármán shedding structures have the highest energy.
Turbulent models of shallow-water equations-based smoothed particle hydrodynamics
Authors: Lirong Tian , Shenglong Gu , Songdong Shao , Yushuai Wu
Published: October 2024

The depth-averaged models such as those based on the shallow water equations (SWEs) are commonly used to simulate the large-scale flows with engineering importance. The smoothed particle hydrodynamics (SPH) approach has been documented to solve the SWEs due to its mesh-free superiority in treating the free surfaces and wet-dry boundaries. However, nearly all SWE-SPH models were developed without a turbulent model, which seriously limited the model applications where the flows are complex and where the turbulent parameters are explicitly needed. For the first time, this paper includes a depth-averaged turbulent k̂-ε̂ model in the SWE-SPH solver, making the model more capable of treating the turbulent flows in the practical field. For comparison purpose, a sub-particle-scale turbulent model widely adopted in three-dimensional (3D) SPH was also included in the present SWE-SPH scheme. To evaluate the performance of the two proposed turbulent SWE-SPH models, various open channel flows of increasing complexity were simulated, and the SPH computations were compared with the reported data in the literature. Through the analysis of results for a rough riverbed, L-shaped and sudden expansion channels, it is demonstrated that the present turbulent SWE-SPH models are equipped with good robustness and accuracy in capturing the shallow water turbulent dynamics, with the potential to be used in practical river and coastal flows. In summary, there are two distinct novelties in the proposed work. First, the mesh-free numerical modeling technique SPH is used to solve the shallow water equations, which enable the model to work in large engineering field through simple and effective tracking of free surfaces and wet-dry boundaries. Second, the proposed research expands the shallow water SPH modeling technique by including robust turbulence simulation capacity. The newly developed model can address more challenging engineering scenarios such as the sediment and pollutant transports when the flow turbulence plays an important role and where the turbulent parameters are explicitly required in the relevant transport equations.
Enhancing the machinability and formability of tool steels through spheroidizing annealing heat treatment
Authors: Algarni Mohammed
Published: October 2024

This research focuses on enhancing the machinability and formability of tool steels by applying different heat treatment scenarios. Machinability is the process of cutting metals with the least energy effort, while formability is the ability of a metal to be shaped into different forms without severe damage. Enhancing machinability and formability improves dimensional tolerance and surface finish and increases the lifetime and reliability of tool steels. This research will use two tool steel materials, “D2” and “O1,” which are widely used in industry. They contain high percentages of carbon by weight (1.55% and 0.95%, respectively). The “O1” tool steel is used in blanking dies and room-temperature cutting tools, whereas the “D2” tool steel is used for carpentry cutting tools and gauges. The different heat treatment scenarios are based on the latest literature, which shows excellent results with other materials. The heat treatment plan is set to cover various scenarios to determine the most effective treatment for machinability and formability. The experimental work will include several mechanical tests: tensile tests, compression tests, hardness tests, and toughness tests. The conclusions regarding the different heat treatments will be based on the test results.
A simple hot wire temperature drift correction based on temperature sensitivity applied to a turbulent shear layer
Authors: Scarano Francesco , Jondeau Emmanuel , Salze Edouard
Published: October 2024

A procedure is proposed to correct temperature drift for hot wire anemometry measurements in turbulent fields where the facility is not equipped with temperature control. The procedure consists of evaluating the wire sensitivity to the temperature by building a voltage-temperature curve. The voltages of both the calibration points and the measurement points are corrected, shifting the voltage values to an arbitrary reference temperature. The correction can be applied to the instantaneous voltages by performing synced temperature measurements with constant current anemometry or constant voltage anemometry cold wire. The efficacy of the method is tested on a turbulent shear layer that develops on the side of an open jet wind tunnel not equipped with temperature control. The velocity statistics show a good match with respect to reference particle image velocimetry measurements, evidencing the self-similarity of the shear layer in contrast with the non-corrected data and the data corrected using the semi-empirical and analytical relation based on King's law modification. A correction based only on the temperature statistics shows indistinguishable results with respect to the instantaneous correction.
Enhanced detection performance based on a differential ME sensor with strong suppression of vibration interference
Authors: Chu Zhaoqiang , Wang Yanpan , Du Zelin , Cui Jianyu , Yu Zhonghui
Published: October 2024

Magnetoelectric (ME) sensors have enormous potential for detecting weak magnetic fields because of their high sensitivity, low power consumption, compact size and, low cost. However, inevitable vibration interference limits their application in practical environments, especially in the case of mobile platform mounting. Here, we propose a differential ME sensor, consisting of PZT macro-fiber composites (MFCs) and Metglas laminates. The differential ME sensor has two output terminals with weak mutual mechanical coupling and works in longitudinal vibration mode. MFC cores are polarized in parallel mode to guarantee their consistency of electric characteristics and reversed bias field is provided by attached magnets. Experimental results show that the differential-mode response amplitudes have a gain of −17.6 dB for low-frequency vibration at 2 Hz and ∼6.2 dB for an applied magnetic field at 3 Hz, in comparison with the single-ended mode. In addition, our proposed ME sensor also has a low inherent equivalent magnetic noise of 18.3 pT/√Hz at 1 Hz. Finally, a target detection experiment in the presence of heavy lab noise and strong vibration interference is conducted and the improved detection performance of the proposed differential ME sensor is proved.
Magnetic sensitive mechanical response in CrSBr and its composite resonators
Authors: Cheng Huanghuang , Zhou Jiayuan , Hu Chao , Söll Aljoscha , Sofer Zdenek , Tian Mingliang , Liu Xue , Yang Fan , Jiang Yuxuan
Published: October 2024

We study the mechanical response of bulk CrSBr in temperature using a CrSBr string resonator. We observe two abrupt changes in eigenfrequency and quality factor of the resonator with decreasing temperature, a strong one around 140 K due to an antiferromagnetic phase transition, and a weaker one around 200 K possibly related to a change of spin correlations. We find that the antiferromagnetic transition persists through a temperature window of 30 K rather than showing a narrow sharp change, indicating a gradual spin transition process. In addition, the quality factor exhibits an unexpected increase during the transition, which violates the theoretical prediction. Finally, we demonstrate that in a CrSBr/SiN composite resonator, its vibrational state is sensitively affected by the constituent CrSBr layer during the magnetic phase transitions. It reveals the potential of a composite resonator in both controlling its vibration state with and probing phase transitions of its constituent materials. Our study not only enriches the details about the antiferromagnetic phase transition in CrSBr, but also opens up possibility in magnetic sensing and in situ tuning using composite mechanical resonators.
Detection of an unintentional Si doping gradient in site-controlled GaN nanowires grown using a Si3N4 mask by spatially resolved cathodoluminescence and Raman spectroscopy
Authors: Gómez Ruiz Mikel , Brubaker Matt D. , Bertness Kris A. , Roshko Alexana , Tornatzky Hans , Ramsteiner Manfred , Brandt Oliver , Lähnemann Jonas
Published: October 2024

Highly uniform arrays of site-controlled GaN nanowires are synthesized by selective area growth using a Si3N4 mask and molecular beam epitaxy. Systematic modulation of the emission along the nanowire axis is observed in spectrally resolved cathodoluminescence linescans. We show that this intensity change is an indicator of unintentional Si incorporation during growth resulting from the interaction between the impinging Ga atoms and the mask material. The gradual reduction of the cathodoluminescence intensity along the nanowire highlights the important role of the growth geometry within the synthesis reactor, with shadowing from the elongating nanowires inhibiting the reaction with the mask. This gradient in Si doping is confirmed by the quenching of the longitudinal optical phonon line measured in Raman spectra along the nanowire axis. The corresponding carrier density is derived from the frequency of the coupled phonon–plasmon mode. The spectroscopic identification of inversion domain boundaries in the majority of the nanowires is also attributed to the Si incorporation. From temperature dependent cathodoluminescence experiments, we derive the activation energy for excitons bound to these defects.
Nonequilibrium steady state full counting statistics in the noncrossing approximation
Authors: Zemach Ido , Erpenbeck André , Gull Emanuel , Cohen Guy
Published: October 2024

Quantum transport is often characterized not just by mean observables like the particle or energy current but by their fluctuations and higher moments, which can act as detailed probes of the physical mechanisms at play. However, relatively few theoretical methods are able to access the full counting statistics (FCS) of transport processes through electronic junctions in strongly correlated regimes. While most experiments are concerned with steady state properties, most accurate theoretical methods rely on computationally expensive propagation from a tractable initial state. Here, we propose a simple approach for computing the FCS through a junction directly at the steady state, utilizing the propagator noncrossing approximation. Compared to time propagation, our method offers reduced computational cost at the same level of approximation, but the idea can also be used within other approximations or as a basis for numerically exact techniques. We demonstrate the method’s capabilities by investigating the impact of lead dimensionality on electronic transport in the nonequilibrium Anderson impurity model at the onset of Kondo physics. Our results reveal a distinct signature of one dimensional leads in the noise and Fano factor not present for other dimensionalities, showing the potential of FCS measurements as a probe of the environment surrounding a quantum dot.
Manipulating formation of different InGaAs/GaAs nanostructures via tailoring As4 flux
Authors: Zhang Wen , Wang Ying , Guo Yingnan , Ma Wenquan , Lee Jihoon , Mazur Yuriy I. , Ware Morgan E. , Salamo Gregory J. , Liang Baolai
Published: October 2024

This research provides a flexible approach to manipulate formation of InGaAs nanostructures on the GaAs (100) surface by varying arsenic (As4) beam equivalent pressure (BEP). By selecting the As4/(In+Ga) BEP ratio to be 4, 8, 20, 50 and 100, we were able to obtain different quantum structures from quantum well (QW) to quantum dots (QDs), then to spatially ordered quantum dot chains (QD-chains), and finally to quantum wires (QWRs), respectively. This transformation of nanostructures was explained by anisotropic surface diffusion coupled with the strain relieving Stranski–Krastanov growth mode, while the anisotropy was modulated by increasing As4 flux and subsequently enhanced by multilayer-stacking growth with a suitable spacer thickness. Photoluminescence characteristics show correlation to the nanostructure morphology for each sample. In particular, the formation of QD-chains and QWRs results in anisotropic features that offer potential device applications.
Cyclic electron flow and Photosystem II-less photosynthesis
Authors: Ermakova Maria , Fitzpatrick Duncan , Larkum Anthony W. D.
Published: October 2024

Oxygenic photosynthesis is characterised by the cooperation of two photo-driven complexes, Photosystem II (PSII) and Photosystem I (PSI), sequentially linked through a series of redox-coupled intermediates. Divergent evolution has resulted in photosystems exhibiting complementary redox potentials, spanning the range necessary to oxidise water and reduce CO2 within a single system. Catalysing nature’s most oxidising reaction to extract electrons from water is a highly specialised task that limits PSII’s metabolic function. In contrast, potential electron donors in PSI span a range of redox potentials, enabling it to accept electrons from various metabolic processes. This metabolic flexibility of PSI underpins the capacity of photosynthetic organisms to balance energy supply with metabolic demands, which is key for adaptation to environmental changes. Here, we review the phenomenon of ‘PSII-less photosynthesis’ where PSI functions independently of PSII by operating cyclic electron flow using electrons derived from non-photochemical reactions. PSII-less photosynthesis enables supercharged ATP production and is employed, for example, by cyanobacteria’s heterocysts to host nitrogen fixation and by bundle sheath cells of C4 plants to boost CO2 assimilation. We discuss the energetic benefits of this arrangement and the prospects of utilising it to improve the productivity and stress resilience of photosynthetic organisms.
Enhancing longevity: the additional benefits of vaccination in older adults
Authors: Woodward Michael
Published: October 2024

Vaccination of older people (over age 60) reduces the impact of some preventable microbial diseases but has additional benefits including reducing cancer, reducing dementia and preventing cardiovascular and cerebrovascular disease. For instance, one study found herpes zoster vaccination reduces incident dementia by up to 28% over the subsequent 7 years. The mechanisms behind these additional benefits are being defined but likely include reduced inflammation and specific targeting of pathogenic proteins. These additional benefits emphasise the importance of a whole-of-life approach to vaccination.
Respiratory virus surveillance in Australia: past, present and future
Authors: Cheng Allen C.
Published: October 2024

Surveillance for respiratory viruses has developed from being solely focused on influenza notification to a more sophisticated system that allows for a more comprehensive picture of the burden, severity and impact of several respiratory viruses. Although all surveillance is associated with some degree of bias, when combined these provide useful information on the respiratory virus activity. However, further improvements are possible using new sources of surveillance, such as linked administrative databases, and taking a broader view of surveillance that provides information for forecasting and on public health control measures.
Recent pandemics and informed predictions
Authors: Perlman Stanley
Published: October 2024

Although the COVID-19 pandemic had many deleterious effects, a positive aspect was that it forced us to ponder how we would approach a future epidemic or pandemic. Here, a set of predictions relevant to pandemic preparedness are discussed, based on our experience with the still ongoing COVID-19 pandemic.
Capturing the mechanosensitivity of cell proliferation in models of epithelium
Authors: Höllring Kevin , Nuić Lovro , Rogić Luka , Kaliman Sara , Gehrer Simone , Wollnik Carina , Rehfeldt Florian , Hubert Maxime , Smith Ana-Sunčana
Published: October 2024

Despite the primary role of cell proliferation in tissue development and homeostatic maintenance, the interplay between cell density, cell mechanoresponse, and cell growth and division is not yet understood. In this article, we address this issue by reporting on an experimental investigation of cell proliferation on all time- and length-scales of the development of a model tissue, grown on collagen-coated glass or deformable substrates. Through extensive data analysis, we demonstrate the relation between mechanoresponse and probability for cell division, as a function of the local cell density. Motivated by these results, we construct a minimal model of cell division in tissue environment that can recover the data. By parameterizing the growth and the dividing phases of the cell cycle, and introducing such a proliferation model in dissipative particle dynamics simulations, we recover the mechanoresponsive, time-dependent density profiles in 2D tissues growing to macroscopic scales. The importance of separating the cell population into growing and dividing cells, each characterized by a particular time scale, is further emphasized by calculations of density profiles based on adapted Fisher–Kolmogorov equations. Together, these results show that the mechanoresponse on the level of a constitutive cell and its proliferation results in a matrix-sensitive active pressure. The latter evokes massive cooperative displacement of cells in the invading tissue and is a key factor for developing large-scale structures in the steady state.
Water quality–fisheries tradeoffs in a changing climate underscore the need for adaptive ecosystem–based management
Authors: Scavia Donald , Ludsin Stuart A. , Michalak Anna M. , Obenour Daniel R. , Han Mingyu , Johnson Laura T. , Wang Yu-Chen , Zhao Gang , Zhou Yuntao
Published: October 2024

Changes driven by both unanticipated human activities and management actions are creating wicked management landscapes in freshwater and marine ecosystems that require new approaches to support decision-making. By linking a predictive model of nutrient- and temperature-driven bottom hypoxia with observed commercial fishery harvest data from Lake Erie (United States–Canada) over the past century (1928–2022) and climate projections (2030–2099), we show how simple, yet robust models and routine monitoring data can be used to identify tradeoffs associated with nutrient management and guide decision-making in even the largest of aquatic ecosystems now and in the future. Our approach enabled us to assess planned nutrient load reduction targets designed to mitigate nutrient-driven hypoxia and show why they appear overly restrictive based on current fishery needs, indicating tradeoffs between water quality and fisheries management goals. At the same time, our temperature results show that projected climate change impacts on hypoxic extent will require more stringent nutrient regulations in the future. Beyond providing a rare example of bottom hypoxia driving changes in fishery harvests at an ecosystem scale, our study illustrates the need for adaptive ecosystem–based management, which can be informed by simple predictive models that can be readily applied over long time periods, account for tradeoffs across multiple management sectors (e.g., water quality, fisheries), and address ecosystem nonstationarity (e.g., climate change impacts on management targets). Such approaches will be critical for maintaining valued ecosystem services in the many aquatic systems worldwide that are vulnerable to multiple drivers of environmental change.
Political practitioners poorly predict which messages persuade the public
Authors: Broockman David E. , Kalla Joshua L. , Caballero Christian , Easton Matthew
Published: October 2024

Do political practitioners have good intuitions about how to persuade the public? Longstanding theories that political elites’ messages have large effects on public opinion and the large sums spent to secure some practitioners’ messaging advice suggest they should. However, findings regarding the surprising limits of expert forecasts in other domains suggest they may not. In this paper, we evaluate how well political practitioners can predict which messages are most persuasive. We measured the effects of

N
=
172

messages about 21 political issues using a large-sample survey experiment (

N
=
67
,
215

respondent-message observations). We then asked both political practitioners (

N
=
1
,
524

practitioners,

N
=
22
,
763

predictions) and laypeople (

N
=
21
,
247

respondents,

N
=
63
,
442

predictions) to predict the efficacy of these messages. The practitioners we surveyed ranged widely in their experience and expertise with persuasive message design. We find that: (a) political practitioners and laypeople both performed barely better than chance at predicting persuasive effects; (b) once accounting for laypeople’s inflated expectations about the average size of effects, practitioners did not predict meaningfully better than laypeople; (c) these results held even for self-identified issue experts and highly experienced practitioners; and (d) practitioners’ experience, expertise, information environment, and demographics did not meaningfully explain variation in their accuracy. Our findings have theoretical implications for understanding the conditions likely to produce meaningful elite influence on public opinion as well as practical implications for practitioners.