bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical studies on the radiation of micro-pressure wave noise at the tunnel exits
Authors: Luo Wenfeng , Wang Honglin , Wu Yudong , Bi Haiquan , Ding Weiping
Published: September 2024

To effectively control the micro-pressure wave noise radiating from tunnel exits, numerical simulations were conducted to investigate the generation and propagation of such noise at the exits of high-speed metro tunnels. Large-eddy simulation was employed to obtain the near-field unsteady flow field data at the tunnel exit. The Ffowcs Williams–Hawkings (FW–H) acoustic analogy was used to predict the types of sound sources for micro-pressure wave noise. The unsteady flow field data were also utilized for finite element method acoustic analysis to calculate the far-field radiation of micro-pressure wave noise. The accuracy of the numerical methods was verified through moving model tests. The results indicate that dipole noise dominates within the micro-pressure wave noise. The tunnel's inner wall contributes most to the dipole sound sources. Dipole noise radiates outward in the form of semi-ellipsoidal waves, with energy mainly concentrated below 20 Hz and a peak frequency of 4 Hz. Furthermore, the decay of dipole noise in the direction of the tunnel exit follows a similar exponential decay pattern to that of an explosion shock wave. When the train speed exceeds 400 km/h, the human ear can distinctly perceive the sonic booms at the tunnel exit.
Atmospheric pressure-induced three-dimensional surface wave propagation in the compressible ocean: Effect of static compression
Authors: Pethiyagoda R. , Das S. , Bonham M. , Meylan M. H.
Published: September 2024

Under the assumptions of linearized water wave theory, we build a three-dimensional mathematical model that couples atmospheric pressure waves and surface ocean waves, including water compressibility and its static part, to simulate Meteotsunami propagation in the ocean. The solution uses the Laplace–Fourier double transformation technique, emphasizing axisymmetry of the mathematical problem and rigorous treatment of a fairly complicated dispersion relation while using inverse transformations. A novel derivation of the axisymmetric atmospheric pressure front is shown. The impact of water compressibility is shown through a comparative graphical representation against the incompressible case. Faster travel of free-surface waves is observed in the incompressible ocean, followed by the cases with and without static compression of the compressible ocean, respectively. The static compression shifts the phase of the acoustic-gravity modes. The locked wave is hardly influenced by the water compressibility and is entangled with the moving pressure front. The model is validated with the observational pressure data and agrees well with our computed pressure profile. Then, the locked wave profile generated from our model agrees well with the deep-ocean assessment and reporting of tsunami data.
Transient dispersion of settling gyrotactic microorganisms in an open channel flow
Authors: Zeng Hanhan , Jiang Weiquan , Wang Bohan , Zeng Li , Guan Mingyang , Li Zhi , Chen Guoqian
Published: September 2024

Dispersion of microorganisms is a key issue in bio-physics and has many applications in the fields of algae cultivation, biomass energy, and wetland ecology. However, there has been limited exploration of the effects of settling behavior and initial release conditions on the transient dispersion of gyrotactic microorganisms. This paper explores the transient dispersion of settling gyrotactic microorganisms in an open channel flow. The moment equations derived from the Smoluchowski equation are solved by the biorthogonal expansion method, and the results are compared with random walk simulations, showing good agreement. The time variations of concentration distribution, drift velocity, and dispersivity of settling gyrotactic microorganism suspension are explored in detail under typical initial release conditions. As illustrated and characterized, settlement weakens the gravitactic focusing of microorganisms near the free surface, leads to accumulation at the bottom, and increases the dispersivity; from a line source release, the relaxation time is shortest, and the microorganisms scatter fastest in the longitudinal direction, while the point source at the water surface leads to the most concentrated longitudinal distribution and the highest drift velocity; furthermore, the initial release condition assumes an important role in shaping the concentration distribution and drift velocity.
OQuPy: A Python package to efficiently simulate non-Markovian open quantum systems with process tensors
Authors: Fux Gerald E. , Fowler-Wright Piper , Beckles Joel , Butler Eoin P. , Eastham Paul R. , Gribben Dominic , Keeling Jonathan , Kilda Dainius , Kirton Peter , Lawrence Ewen D. C. , Lovett Brendon W. , O’Neill Eoin , Strathearn Aidan , de Wit Roosmarijn
Published: September 2024

Non-Markovian dynamics arising from the strong coupling of a system to a structured environment is essential in many applications of quantum mechanics and emerging technologies. Deriving an accurate description of general quantum dynamics including memory effects is, however, a demanding task, prohibitive to standard analytical or direct numerical approaches. We present a major release of our open source software package, OQuPy (Open Quantum System in Python), which provides several recently developed numerical methods that address this challenging task. It utilizes the process tensor approach to open quantum systems (OQS) in which a single map, the process tensor, captures all possible effects of an environment on the system. The representation of the process tensor in a tensor network form allows for an exact yet highly efficient description of non-Markovian OQS (NM-OQS). The OQuPy package provides methods to (1) compute the dynamics and multi-time correlations of quantum systems coupled to single and multiple environments, (2) optimize control protocols for NM-OQS, (3) simulate interacting chains of NM-OQS, and (4) compute the mean-field dynamics of an ensemble of NM-OQS coupled to a common central system. Our aim is to provide an easily accessible and extensible tool for researchers of OQS in fields such as quantum chemistry, quantum sensing, and quantum information.
Hysteresis in strongly magnetized N2 discharges
Authors: Hyde A. , Batishchev O.
Published: September 2024

A semi-empirical global model for a nitrogen discharge in a strong magnetic field is developed. The model is based upon experimental data from high-resolution Doppler and extreme-ultraviolet vacuum spectroscopy, which establish the plasma composition, discharge parameters, and, most importantly, electronic transitions. This allows the number of required molecular systems and atomic/ionic states to be reduced, thereby retaining only the essential plasma chemistry reactions. The set of 35 stiff non-linear ordinary differential equations is numerically integrated using an unconditionally stable adaptive method. Simulations show the existence of two solution branches with low and high electron temperature, respectively. A distinct hysteresis is exhibited by the discharge and illustrated for three typical N2 mass flow rates. The dependencies of the plasma parameters on the applied power are presented and discussed in detail, including in the vicinity of the bifurcation points. The efficiency of operation in the opposing limits of N2 discharge behavior as either a source of plasma or light emission is examined, with special emphasis on electric propulsion capabilities.
High-precision ultrasonic atomization using oscillating microchannels: Interplay of three-dimensional vibrational modes and droplet ejection mechanisms
Authors: Shenoda Abanoub , Brenker Jason , Alan Tuncay
Published: September 2024

Ultrasonic atomization is a critical process for producing micrometer-diameter droplets, widely utilized in aerosol drug delivery, spectrometry, and printing. The geometry of the vessel containing the fluid being atomized and the oscillations of its sidewalls play a crucial role in controlling the wave patterns and hence the droplet ejection process, especially at actuation frequencies exceeding 1 MHz. However, the mechanisms behind droplet ejection under high-frequency ultrasonic actuation remain poorly understood. We employ oscillating high-aspect-ratio Silicon microchannels to create ideal conditions where capillary forces, microchannel geometry, and oscillatory motion work together to precisely confine a liquid film and generate droplets with controlled diameters. We show that the three-dimensional vibrations of the microchannels, particularly the interplay between actuation frequency, amplitude, and channel geometry, can be used to effectively tune the ligament development and droplet breakup. This understanding allows us to establish conditions to reduce actuation power and hence minimize heating, control shear stresses and tune the droplet size on-demand without compromising uniformity and throughput.
Relationship of flow pattern, vibration, and noise in automobile refrigerant system and flow pattern identification based on convolutional neural network
Authors: Zhao Qin , Zhu Xin-Gang , He Yan-Song , Jia Wen-Yu , Zhou Zhi-Fu
Published: September 2024

In recent years, the flow-induced vibration and noise in automotive refrigerant system gradually become the main factor affecting driving comfort. However, the relationship of flow pattern, vibration, and noise is not clear, and pattern identification is not easy but necessary. In this paper, a series of experiments are conducted to investigate the relationship of flow pattern, flow-induce vibration, and noise near the thermal expansion valve in an automobile refrigerant system. The flow pattern, vibration, and noise are closely related to startup processes. Mist flow, which contains more mist two-phase mixture than transition flow and wispy-annular flow, leads to the largest amplitude of vibration and strong broadband hiss noise. Moreover, the increase in compressor speed promotes the pattern transition and the vibration amplitude in time domain but has no effect on the distribution of vibration peaks in frequency spectrum. Finally, a short-time Fourier transform and convolutional neural network combined method for flow pattern identification is developed based on the relationship of flow pattern and flow-induced noise. After using transfer learning and data augmentation, four trained network architectures show relatively high accuracy above 94% for test set. Among them, ResNet34 not only has the highest accuracy of 98.8% but also can recognize each type of flow pattern. The generalization of this method can help engineers to recognize flow patterns in air conditioning without flow visualization but only need to measure sound signals.
Anisotropic elasticity measurements of the retina using optical coherence elastography
Authors: Ma Jiawei , Fan Fan , Wang Chongyang , Ma Zongqing , Meng Xiaochen , Gao Xinxiao , Zhu Jiang
Published: September 2024

Anisotropic elasticity measurements of the retina are essential for retinal disease diagnosis and function assessment. Optical coherence elastography (OCE) is a high-resolution imaging technique for mapping the elasticity distribution of tissues. However, previous OCE measurements quantified the tissue elasticity in a single direction, resulting in a biased estimation of the elastic properties. In this study, we propose an OCE method with acoustic radiation force (ARF) excitation to map the retinal anisotropic elasticity in the depth and lateral directions. The axial elasticity was analyzed using the natural frequency of free vibration, and the lateral elasticity was quantified using the elastic wave velocity. After evaluating the feasibility of the OCE method on the phantoms, the anisotropic elasticity of ex vivo porcine retinas was mapped. The results show that the OCE method with ARF excitation can assess the elasticity in orthogonal directions and provide a comprehensive understanding of the elasticity of the anisotropic tissues.
Numerical study on bifurcation characteristics of wind-induced vibration for an H-shaped section
Authors: Hu Peng , Yuan Bangrong , Han Yan , Li Kai , Cai C. S. , Chen Xu
Published: September 2024

In order to reveal the influence of initial excitation on the bifurcation phenomenon of bridge decks, a new perspective of flow characteristics is developed based on the computational fluid dynamics numerical simulation method. Then, the bifurcation mechanism of vortex-induced vibration (VIV) response and nonlinear flutter response of the H-shaped section is investigated. The results show that when the wind speed is 2 m/s, under a small torsional excitation of 0.5°, the flow field of the H-shaped section will develop into the vortex shedding mode of the vertical vibration, resulting in vertical VIV. However, while under a large excitation of 6°, the flow field will directly transform into the vortex shedding mode of the torsional vibration, resulting in torsional VIV. Therefore, the bifurcation phenomenon of the VIV response is observed. When the wind speed is 4 m/s, the H-shaped section exhibits a nonlinear flutter limit cycle oscillation under a large excitation of 8°, but its response can be ignored under a small excitation of 0.5°. This phenomenon is attributed to the significant change in the transition of the vortex shedding mode from a small amplitude to a stable large amplitude, and the flow field lacks enough energy to complete the transition of the vortex shedding mode, resulting in the bifurcation phenomenon of the nonlinear flutter response. When the wind speed is 3.0 m/s, the large excitation will change the vortex shedding frequency of the new H-shaped section, resulting in the torsional VIV.
Revealing the molecular structures of α-Al2O3(0001)–water interface by machine learning based computational vibrational spectroscopy
Authors: Du Xianglong , Shao Weizhi , Bao Chenglong , Zhang Linfeng , Cheng Jun , Tang Fujie
Published: September 2024

Solid–water interfaces are crucial to many physical and chemical processes and are extensively studied using surface-specific sum-frequency generation (SFG) spectroscopy. To establish clear correlations between specific spectral signatures and distinct interfacial water structures, theoretical calculations using molecular dynamics (MD) simulations are required. These MD simulations typically need relatively long trajectories (a few nanoseconds) to achieve reliable SFG response function calculations via the dipole moment–polarizability time correlation function. However, the requirement for long trajectories limits the use of computationally expensive techniques, such as ab initio MD (AIMD) simulations, particularly for complex solid–water interfaces. In this work, we present a pathway for calculating vibrational spectra (IR, Raman, and SFG) of solid–water interfaces using machine learning (ML)-accelerated methods. We employ both the dipole moment–polarizability correlation function and the surface-specific velocity–velocity correlation function approaches to calculate SFG spectra. Our results demonstrate the successful acceleration of AIMD simulations and the calculation of SFG spectra using ML methods. This advancement provides an opportunity to calculate SFG spectra for complicated solid–water systems more rapidly and at a lower computational cost with the aid of ML.
Macroscopic modeling of gas permeability in hierarchical micro/nanoporous media: A unified characterization of rarefaction using Klinkenberg theory and equivalent diameter
Authors: Sabet Safa , Barisik Murat
Published: September 2024

Estimating gas transport through a hierarchical micro/nanoporous system is challenging due to non-equilibrium gas dynamics. The primary difficulty lies in determining the rarefaction level, because identifying a representative flow dimension in a complex porous system with multiple pore scales is not straightforward. Our study performed a pore-level analysis for gas permeability in dual-scale porous media with varying porosity, throat size, and secondary pore size under different rarefaction conditions. We found that secondary porosity negatively affects permeability due to increased friction forces, with this influence growing as the secondary pore size and porosity increase until the secondary pore becomes comparable to the throat. However, rarefaction reduces the effects of secondary pores due to boundary slip. Traditional Knudsen number (Kn) calculations based on Darcy-defined height failed to accurately describe the rarefaction effects on gas permeability. Instead, we introduced an equivalent diameter to calculate the Kn, which provided an accurate normalization of apparent gas permeability independent of pore geometry. The extended Kozeny–Carman–Klinkenberg model developed in our previous study successfully yielded a macroscopic model for apparent gas permeability in hierarchical micro/nanoporous systems as a function of the traditional Darcy height and porosity.
Experimental investigation into effects of combustor structure on characteristics of rotating detonation of cracked kerosene gas
Authors: Han Jiaxiang , Yang Jianlu , Wang Jinping , Bai Qiaodong , Xiao Qiang , Wu Yuwen , Zheng Quan , Weng Chunsheng
Published: September 2024

This study examines the influence of the structure of the combustor on the propagation of rotating detonation waves (RDWs) of cracked kerosene gas (CKG) by using oxygen-rich air, with mass fractions of oxygen of 36% and 48%, as the oxidant while maintaining stable values of the state parameters of CKG. The experimental results showed that the structure of the combustor played a key role in the initiation and stable propagation of CKG, and suitable values of its width and the width of its outlet promoted the stable self-sustained propagation of the RDWs. Combustors of 8 and 14 mm width failed to initiate with 36% oxygen-rich air and without blockage ratio. In the combustors of 20 and 26 mm width, as the blockage ratio increased, the modes of propagation of the RDW included a single stable RDW, intermittent single RDW, and four, six, and eight counter-rotating RDWs. With the further increase in the blockage ratio, the reflected shock wave at the end of the combustor was enhanced, resulting in an increase in the number of RDW wave heads. As a result, the height of the fresh fuel layer was decreased, the mixing time was decreased and led to a decrease in the RDW velocity. The increase in the width of the combustor was conducive to the radial and axial diffusion of fuel and oxidizer in the combustor, which led to an obvious increase in the propagation velocity of RDW. In the 26 mm width combustor, the maximum RDW velocity is 1769 m/s.
Evolution law of flow characteristics for straight pipeline after leaking
Authors: Wang Dongpu , Zheng Hongyang , Niu Chunyang
Published: September 2024

Aiming at the leakage problem of the fluid loop system for the thermal control system of spacecraft caused by the impact of micro-meteoroid and orbital debris, we investigate the dependence of the leak rate, pressure drop and flow characteristics before and after leaking on leak position, inlet pressure, and leaking aperture, calculated in a straight pipeline with single leakage, using stationary and transient three-dimensional computational fluid dynamics simulations with commercial software (FLUENT). The working fluid adopts single-phase water without gravity. It is found that the pressure increases obviously near the leak point, which is caused by the local peak of pressure. As the length between the leak point and the inlet becomes larger, the local peak of pressure and the dimensionless leak rate are smaller. When the inlet pressure increases, the leaked mass flow rate increases; however, the ratio of the leaked flow rate to inlet flow rate decreases. Furthermore, it is observed that the dependence of dimensionless leaking rate on dimensionless leaking aperture has a scaling relation with the scaling exponent approximating to 2, which may be related to the proportion of the vortex formed by the backward flow at the leak hole, the amplitude, and the affected length along the pipe of the local peak of pressure. This study is instructive and meaningful to the leak detection and plugging of fluid loop in space.
Rotation-invariant image recognition using interconnected floating-gate phototransistor
Authors: Pan Xuan , Shi Jingwen , Yu Wentao , Zhao Yichen , Yang Yuekun , Cheng Bin , Liang Shi-Jun , Miao Feng
Published: September 2024

Rotational invariance is fundamental for robust image recognition systems, ensuring accurate analysis irrespective of image orientation. However, existing systems predominantly reliant on software often encounter challenges such as increased computational demands and compromises between processing speed and accuracy. In this study, we propose leveraging the interconnected floating-gate (FG) structure as an effective hardware-level solution to achieve rotational invariance in image recognition. Our design features a reconfigurable two-dimensional material FG phototransistor array, where each processing unit integrates four sensory devices sharing a common FG. This configuration facilitates uniform distribution of stored charges across the interconnected FG layer, which is typically made of metal, enabling consistent application of a single weight matrix to images across varied rotational conditions. The photoactive material, tungsten diselenide (WSe2), possesses a distinctive bipolar property that facilitates both hole and electron tunneling into the FG layer. This property directly contributes to the efficiency of state transition within the setup and improves its overall adaptability. In this manner, our design achieves stable and predictable outputs in recognizing identical digital numbers regardless of their rotation, while also demonstrating variable performance essential for accurately distinguishing between different digital numbers. This dual capability guarantees both the adaptability and precision required for rotation-invariant image recognition, suggesting that our work may open up a promising venue for exploring advanced hardware designs, such as optimized interconnected FG architectures, tailored for enhancing recognition accuracy and efficiency in the field of intelligent visual systems.
Dopant induced polarization and breakdown balance via multilayer thin films with different crystallinities for energy storage in PZT homostructures
Authors: Zhou Yanjun , Ma Xia , Xiao Shihong , Zhou Fei , Wei Xianhua
Published: September 2024

Multilayer thin films have been demonstrated to enhance the energy storage performance of dielectric capacitors, due to the synergistic effects of different functional layers in heterostructures. In this Letter, a multilayer structure is proposed based on the Pb(Zr0.52Ti0.48)O3 (PZT) homostructure. It has been experimentally demonstrated that the alternative PZT layer exhibits different crystallinity induced by Ce dopant incorporation. Thus, the polarization and breakdown strength are well balanced, giving rise to a high recoverable energy density of 74 J/cm3 with a high breakdown electric field of 6.49 MV/cm and a relatively large polarization of 28 μC/cm2. The homostructures provide a simple method to construct dielectric multilayer films to promote energy density only via one-step annealing treatment and one type of dielectric material.
Mesocarnivores in residential yards: influence of yard features on the occupancy, relative abundance, and overlap of coyotes, grey fox, and red fox
Authors: Johansson Emily P. , DeGregorio Brett A.
Published: September 2024

Context As conversion of natural areas to human development continues, there is a lack of information about how developed areas can sustainably support wildlife. While large predators are often extirpated from areas of human development, some medium-bodied mammalian predators (hereafter, mesocarnivores) have adapted to co-exist in human-dominated areas. Aims How human-dominated areas such as residential yards are used by mesocarnivores is not well understood. Our study aimed to identify yard and landscape features that influence occupancy, relative abundance and spatial-temporal overlap of three widespread mesocarnivores, namely, coyote (Canis latrans), grey fox (Urocyon cineroargenteus) and red fox (Vulpes vulpes). Methods Over the summers of 2021 and 2022, we deployed camera-traps in 46 and 96 residential yards, spanning from low-density rural areas (<1 home per km2) to more urban areas (589 homes per km2) in north-western Arkansas, USA. Key results We found that mesocarnivore occupancy was marginally influenced by yard-level features as opposed to landscape composition. Fences reduced the occupancy probability of coyotes, although they were positively associated with the total area of potential shelter sites in a yard. We found that relative abundance of grey fox was highest in yards with poultry, highlighting a likely source of conflict with homeowners. We found that all three species were primarily nocturnal and activity overlap between the species pairs was high. Conclusions Thus, these species may be using spatio-temporal partitioning to avoid antagonistic encounters and our data supported this, with few examples of species occurring in the same yards during the same 24-h period. Implications As the number of residential yards continues to grow, our results suggested that there are ways in which our yards can provide resources to mesocarnivores and that homeowners also have agency to mitigate overlap with mesocarnivores through management of their yard features.
Repetition dynamically and rapidly increases cortical, but not hippocampal, offline reactivation
Authors: Yu Wangjing , Zadbood Asieh , Chanales Avi J. H. , Davachi Lila
Published: September 2024

No sooner is an experience over than its neural representation begins to be transformed through memory reactivation during offline periods. The lion’s share of prior research has focused on understanding offline reactivation within the hippocampus. However, it is hypothesized that consolidation processes involve offline reactivation in cortical regions as well as coordinated reactivation in the hippocampus and cortex. Using fMRI, we presented novel and repeated paired associates to participants during encoding and measured offline memory reactivation for those events during an immediate post-encoding rest period. post-encoding reactivation frequency of repeated and once-presented events did not differ in the hippocampus. However, offline reactivation in widespread cortical regions and hippocampal-cortical coordinated reactivation were significantly enhanced for repeated events. These results provide evidence that repetition might facilitate the distribution of memory representations across cortical networks, a hallmark of systems-level consolidation. Interestingly, we found that offline reactivation frequency in both hippocampus and cortex explained variance in behavioral success on an immediate associative recognition test for the once-presented information, potentially indicating a role of offline reactivation in maintaining these novel, weaker, memories. Together, our findings highlight that endogenous offline reactivation can be robustly and significantly modulated by study repetition.
Emerging engineering scholars’ stance in citations
Authors: Zhang Genggeng
Published: September 2024

This paper presents a mixed-method study that integrates genre-based corpus analysis and discourse-based
interviews to examine the form- and stance-related citation patterns in the research articles of ten first- and second-year
engineering doctoral students. The corpus analysis reveals strong preferences for stance-marked citations and the
proclaim and entertain devices in particular, suggesting that writers use authorial stance to endorse cited
propositions or provide likelihood- or evidence-based judgments in citations. Interview results indicate a discordance between
writers’ intentions and their stance-related linguistic choices, as well as varied perceptions of authorial stance. Despite the
frequent use of stance markers in citations, most writers claimed to be neutral reporters of knowledge. Only a few acknowledged
their strategic stance choices and demonstrated a comprehensive understanding of the rhetorical roles citations play in their
claim-making practices. The findings suggest that students with developing citation expertise lacked the academic and disciplinary
expertise to understand the interplay among citations, authorial stance, and rhetorical move/step structures in their research
writing. These writers could benefit from explicit feedback that raises their awareness of the strategic use of citations and
stance, to facilitate the realization of rhetorical goals in research writing.
An integrated look at forms of address in Chilean Spanish using a contextualized picture-translation
task
Authors: Fernández-Mallat Víctor
Published: September 2024

This study uses an innovative contextualized translation task method and a quantitative variationist approach to
offer an integrated look at second person singular address forms in Chilean Spanish, a Latin American variety with a tripartite
address system that includes tuteo, ustedeo, and voseo forms. Results reveal that
ustedeo has remained largely unaffected by recent changes in Chile’s address system and that this system’s
main alternation is between tuteo and voseo, which function as competing variants. Results also
provide further evidence that the documented shift towards a preference for voseo forms over
tuteo forms in familiar address is led by members of the younger generation, especially men, and has the
Central Region of the country as its epicenter. Finally, results suggest that, notwithstanding the shift from
tuteo to voseo, the latter is unlikely to completely oust the former from Chile’s address
system due to both linguistic and social reasons.
Bad business practices in the language services industry
Authors: Carreira Oliver
Published: September 2024

The language services industry has enjoyed consistent economic growth over the past 15 years, yet not all
participants have reaped its benefits. Individual language professionals have faced persistently low rates of pay, a lack of
social benefits, and reduced job security. This predicament has been exacerbated by disruptions brought by technologies such as
machine translation and artificial intelligence, and the questionable business practices of language services providers.

Existing research primarily focuses on economic and technological aspects, overlooking the experiences of
linguists. This article seeks to broaden this area of study by compiling a comprehensive list of the bad business practices that
individual practitioners experience. A survey of 682 freelance translators provides the foundation, yielding a catalogue of 17
detrimental practices along with their prevalence rates. The article also outlines proposals for addressing these issues and
identifies potential avenues for future research in this domain.
Flow-through microfluidic relative permittivity sensor using highly-doped silicon sidewall electrodes
Authors: Bonnema M J S , Veltkamp H-W , Alveringh D , Wiegerink R J , Lötters J C
Published: September 2024

This paper reports a flow-through sensor for the real-time measurement of the relative permittivity of a flowing fluid. The proposed sensor contains multiple parallel microchannels. Each channel acts as a parallel plate capacitor in which the electrodes are isolated from the fluid. This approach results in a low pressure drop and high sensitivity while the internal volume is only 50 nl. The fabrication technology allows for controllable scaling of the channel geometry. Equally deep microchannels with widths varying between 5 µm and 50

μ

m are fabricated. The fabrication technology is compatible with other flow-through sensors, enabling further on-chip integration. The sensor has been characterised using 10 different fluids with relative permittivity values ranging from 1 to 80—including water and water-containing mixtures—at a measurement frequency of 300 kHz. The results show an accuracy within 3% of full scale and the repeated measurements with nitrogen and water show standard deviations of 1.20 and 1.03, respectively.
Investigation of a piezoelectric ultrasonic surface wave transducer that minimizes structural scattering
Authors: Zhu Xinjie , Zhang Jie , Deng Mingxi , Yao Sen , Gao Yang
Published: September 2024

The structure of the transducers for surface ultrasound wave sensing introduces structural scattering that affects the transducer’s performance. A numerical model of an ultrasonic surface wave transducer was established. Numerical simulations and dynamic acoustic analysis were performed to systematically assess the effects of the transducer parameters, such as the front and back angles, matching layer, and front wedge shape, on structural scattering. The results show that the acoustic amplitude of the transducer structure’s scattered waves is basically stable when the back angle of the wedge is 64°–68° and the front angle is 65°–85°. The amplitude obtained from a transducer with orthogonal slots and a front uniform matching layer is 61% lower for the primary structure scattering, and 56% lower for the secondary structure scattering. When equipped with the upper matching layer, the amplitude of the secondary structural scattering echo is reduced by 78.2%. The experimental results show that the transducer with orthogonal slots on the wedge and a matching layer at the front and upper edges has a signal-to-noise ratio of 19.6 dB when detecting the echo signal of a φ8 through-hole in a welded steel plate, indicating good detection capability. The experiment validates the numerical simulation results. The proposed transducer can be used for structural monitoring of welded structures and flaw detection.
The effect of channel size and wall erosion on the low-frequency oscillation in Hall thruster
Authors: Chen Long , Chen Junyu , Tan Congqi , Duan Ping , Liu Xintong , Liu Miao , Fa Meichen , Feng Jie , Zhang Xueer , Zheng Bocong
Published: September 2024

Hall thrusters are electric propulsion devices widely used on spacecraft. The stability of Hall thrusters is often disturbed by low-frequency oscillations (LFOs) around 5–100 kHz, known as the ‘breathing mode’, typically observed through fluctuations in channel discharge current and plasma parameters. Experimental studies on Hall thrusters with a wide range of sizes show that LFOs exhibit distinct characteristics depending on the channel structures. The size of the channel can modify the particle-wall interactions, electric potential distribution, and electron temperature, thereby influencing the performance of LFOs. Furthermore, the long-term operation of thrusters can cause significant wall erosion, altering the geometry of the discharge channel, which further impacts LFOs. In this work, a one-dimensional fluid model is established to explore the influences of structure sizes and wall erosion of the channel on the LFO characteristics. Both the thruster channel and the plume region are included in the model, and a modified and more precise approach to calculating the electron energy loss at the wall is proposed, which takes into account the influences of secondary electron emission and the channel cross-sectional area. The simulation results indicate that choosing a narrower or longer channel structure has a significantly suppressing effect on LFOs. An erosion model is established according to the cited experimental data to construct the eroded channel structure and to investigate the effect of channel erosion on the breathing mode, which shows that wall erosion can exacerbate LFOs and impact the performance of the thruster.
Anomalous lattice contraction and emerging topological phases in Bi-substituted Sm2Ir2O7
Authors: Telang Prachi , Bandyopadhyay Abhisek , Meneghini Carlo , Carlomagno Ilaria , Singh Surjeet
Published: September 2024

We demonstrate that substituting Bi for Sm in the pyrochlore Sm2Ir2O7 induces an anomalous lattice contraction, with

Δ
a
∼
−
0.012

Å observed at 10% Bi substitution, where ‘a’ denotes the lattice constant. Beyond 10% Bi substitution, the lattice expands according to Vegard’s law. Within this anomalous substitution range, the resistivity shows a

1

/

T

behavior up to 2% Bi-substitution, while near 10% substitution a -lnT dependence is observed. These resistivity behaviors suggest the possibility of a Weyl phase up to 2% Bi substitution, which transforms to a semimetallic quadratic band touching (QBT) topological phase near 10%. For the intermediate composition (Sm0.95Bi0.05)2Ir2O7, the resistivity scales as

1

/

T

1

/

4

, possibly due to its proximity to a proposed quantum critical point at the Weyl-QBT phase boundary (Savary et al 2014 Phys. Rev. X
4 041027). The samples were characterized using synchrotron powder x-ray diffraction, x-ray near-edge fine structure (XANES), and Extended x-ray absorption fine structure (EXAFS) probes. Additionally, magnetic susceptibility and heat capacity measurements were conducted to provide further support.
Experimental magnetic-semiconductor features of the theoretically half-metallic perovskite CaLaTiFeO6
Authors: Avellaneda Martínez J D , Ibáñez-Sotelo J S , Velásquez Moya X A , Deluque Toro C E , Landínez Téllez D A , Roa-Rojas J
Published: September 2024

In this manuscript, the synthesis process of the CaLaTiFeO6 material is shown. The crystallographic structure analysis reveals its monoclinic perovskite type nature (space group P21/n, #14), its morphological strongly granular characteristics, its optical response yields its semiconducting character with a 0.61 eV bandgap and its ferromagnetic property at temperatures T > 350 K are reported. Likewise, calculations and analysis of the electronic properties are performed through density functional theory, which showed correlation with the experimental results. The results allow classifying the CaLaTiFeO6 material as a ferromagnetic semiconductor at room temperature, making it a good candidate for the design of spintronic devices.
Influence of polarization of hot nuclear matter on the anomaly of surface diffuseness of inter-nuclear potential
Authors: Ramezani Sani S , Gharaei R , Rahnamaye Aliabad H A
Published: September 2024

The fusion excitation functions for 12 colliding systems with 96 ≤ Z
1
Z
2 ≤ 608 are analyzed using coupled-channel (CC) calculations based on the M3Y double-folding (DF) potential supplemented with a repulsive potential that takes into account the incompressibility of the nuclear matter. We also applied the polarization effects of hot nuclear matter (PEHNM) on the calculations of the bare nucleus–-nucleus interaction potential within the framework of the modified density-dependent Seyler–Blanchard (SB) approach in the T
2 approximation. Our results reveal that we obtain a nice description of the experimental data of different fusion systems when we use the present theoretical approach to calculate the energy-dependent values of the fusion cross sections. In this paper, the influence of the PEHNM on the surface diffuseness parameter of the Woods–Saxon (WS) potential is also studied. In order to reach this goal, we extract the corresponding values of this parameter based on the modified form of the DF potential (M3Y+Repulsion+polarization). We find that the extracted values are located in a range between a = 0.61 and 0.80 fm at different incident energies. It seems that the polarization effects of hot nuclear matter play a key role in describing the abnormally large values of the nuclear potential diffusenesses in the heavy-ion fusion reactions. Additionally, the regular decreasing trend for the diffuseness parameter of the nucleus–nucleus potential with the increase in the bombarding energies is also observed.
An Approach to Gamma-Hadron Separation via Measurements of the Middle-UV Fraction of EAS emission by an Imaging Atmospheric Cherenkov Telescope with UV-Sensitive SiPM detectors
Authors: Kholupenko Evgeny Evgenievich , Badmaev Danr , Budnev Nikolay , Bykov Andrei Mikhailovich , Krassilchtchikov Alexander , Kuzmichev Leonid Aleksandrovich , Bogdanov Alexander , Chichagov Yuriy , Repman George , Tuboltsev Yuriy
Published: September 2024

The operation of a small-size Cherenkov gamma-ray telescope TAIGA-IACT with camera on SiPMs OnSemi MicroFJ-60035 has been modelled by multiparticle Monte Carlo (MC) methods. The model implies that telescope camera is equipped with two specific types of filters of 290 - 590 nm (visible+NUV) and 220 - 320 nm (MUV+UVB)-bands, each covering half of the camera pixels in some uniform order. This allows one to measure the fraction of UV-radiation in total amount of Cherenkov radiation of an extensive air shower (EAS), that can be used for efficient gamma-hadron separation. The corresponding quality factor takes values up to 5.07 in the 10 - 100 TeV range depending on the distance to EAS axis and camera orientation.
First SOLPS-ITER modelling of an X-point radiator in ITER
Authors: Poletaeva A. , Rozhansky V. , Kaveeva E. , Korzueva V. , Senichenkov I. , Veselova I. , Pitts R.A. , Bonnin X.
Published: September 2024

For the first time, an X-point radiating (XPR) regime using neon (Ne) seed impurity has been obtained in ITER modelling with the SOLPS-ITER code, including fluid drifts. The highly radiating pattern is qualitatively similar to those observed experimentally in ASDEX Upgrade and JET. Comparison of the simulation results with those obtained from modelling of the same regime, with the same approach, in ASDEX Upgrade is used to analyse the difference between the XPR in large and medium-sized machines. Analysis demonstrates that the cold X-point formation is controlled principally by the Ne radiation. The simulation results for the poloidal scale of the intense radiating zone are in good agreement with analytic estimates.
Two-dimensional Diffusion with a Transverse Gravitational Force: Analytical, Numerical and Simulations Results
Authors: Pompa-García Ivan , Metzler Ralf , Dagdug Leonardo
Published: September 2024

Using the Kalinay and Percus projection method a new effective diffusion coefficient is found. This diffusivity generalizes the well-known results previously reported in the literature. Specifically, it is a coefficient that can be applied to two-dimensional asymmetrical channels under an external gravitational-like potential. Furthermore, Brownian Dynamics simulations are performed, and their agreement with the theoretical results is shown. Also, the Mean First-Passage Time is studied for two-dimensional straight conical channels, where the analytical results are analyzed to understand its applicability range using numerical methods, which are compared with Brownian Dynamics simulations. A remarkable result is also presented: the Mean First-Passage Time assumes a minimum at finite values of the external potential amplitude.
Q-triplet characterization of atmospheric time series at Antofagasta: A missing values problem
Authors: Farfán-Bachiloglu Hishan , Calderón Francisco A. , Pérez Darío G.
Published: September 2024

Located in northern Chile (23.7°S, 70.4°W), Antofagasta has an exceptionally arid and stable climate characterized by minimal precipitation and consistent weather patterns. Nevertheless, despite these climate conditions being meaningful for several research and practical applications, our understanding of weather dynamics remains limited. The available meteorological data from 1969 to 2016 is analogical, which presents a significant challenge to analyze because these records are riddled with missing values, some measurements were taken at irregular measuring intervals, making it an interesting puzzle to grasp the Antofagasta’s climate scenario. To overcome this issue, we present a comprehensive statistical analysis of atmospheric temperature, pressure, and humidity time series. Our analytical approach involves the q-triplet calculation method, serving as a powerful tool to identify distinctive behavior within systems under non-equilibrium states. Our results suggest that, in general, the q-triplet values satisfy the condition q
sens < 1 < q
stat < q
rel, a pattern that has been observed in previous studies.
Recent progress on carbon footprint assessment of healthcare services
Authors: Jerin Afsana , Mahmud M A Parvez , Ackland M Leigh , Kouzani Abbas Z
Published: September 2024

As a result of the carbon-intensive nature of health care, hospital facilities are contributors to global warming. Health care’s contributions to global warming and greenhouse gas emissions include those associated with carbon emissions, energy consumption, pharmaceuticals, travel-related emissions and procurement. This article presents a review of environmental impact of different medical services. The published research articles focused on estimating the carbon footprint of healthcare services are investigated here. This review also discusses methods used for determining greenhouse gas emissions. Life cycle assessment and component analysis are the two most used methods for calculating emissions. This study also highlights the existing challenges related to estimation of carbon emission of different healthcare services and ways to overcome these challenges associated with carbon emission. The findings reveal substantial variability in carbon footprint estimates depending on region, settings, and usage patterns, with energy consumption identified as the primary source of greenhouse gas emissions. The review also addresses challenges in data availability, the accuracy of estimations, and the exclusion of critical factors like the environmental impact of medical equipment manufacturing. To mitigate healthcare’s carbon footprint, the study underscores the importance of transitioning from fossil fuels to renewable energy, minimizing unnecessary medical procedures, and promoting the use of reusable instruments. These insights are essential for developing more accurate and comprehensive strategies to reduce the carbon footprint of healthcare services globally.
Introduction
Authors: McClure Laura
Published: September 2024

The introduction examines post-classical representations of Phryne to show how nineteenth- and early twentieth-century artists refashioned her into an icon for their own age, as a harbinger of alternative sexualities, new representational modes, and diverse Hellenisms. By examining the uses of Phryne in the modern era, the chapter illustrates the challenges implicit in separating fantasy from fact in all of the accounts of the hetaera from antiquity onward. It argues that Phryne’s signature characteristic is her ability to elude definition, to be continually re-imagined and transformed in ways that reflect shifting historical realities and values.
Epilogue
Authors: McClure Laura
Published: September 2024

The epilogue reviews the strands of the argument set forth in the previous chapters and then returns to Jean-Léon Gérôme’s painting, Phryne before the Aereopagus. I show how the painter combines the two main strands of Phryne’s narrative, her assimilation to the Cnidian Aphrodite and her trial for impiety, much as in Athenaeus’ original text, but with a view to sexualizing and objectifying the hetaera for nineteenth-century male viewers and the lucrative art market that catered to them. It illustrates how her receptions, from the fourth century BCE to the modern age, continually reinvented Phryne, distorting, mythologizing, and occluding the historical woman, who, despite every effort, still remains beyond our grasp.