bluuebunny/crossref_metadata_2025 huggingface dataset:
Spreading characteristics and influence factors of raindrop impact on the vehicle roof-mounted camera protective surface under airflow
Authors: Li Qiliang , Shao Yu , Chen Shuo , Xu Kaili , Yu Zhiyuan , Li Luoyi , Li Jie
Published: January 2025

In order to understand the dynamic characteristics of raindrops hitting the protective surface of the roof camera during normal vehicle operation, the realizable K-Epsilon turbulence model, volume of fluid method, and liquid film model are employed to simulate the surrounding flow field, self-shape, and dynamic characteristics of the fluid film before and after raindrop impact. Under uniform inflow conditions, the simulation results of the pressure on the isolated camera protection surface, the motion trajectory before collision, and the spreading diameter after collision are verified by wind tunnel tests. A multiphase flow subdomain model of the roof camera protection surface is established to investigate the effects of various single raindrop diameters and distances from the impact surface, as well as the effects of double raindrop arrangements, under the actual incoming flow. As for the single raindrop, reducing the initial raindrop height increases the spreading area and decreases both global and local liquid film thickness. Furthermore, when the initial raindrop diameter is increased by 10%, there is an observed increase in both spread area and liquid film thickness compared to the baseline. As for the double raindrops, the spreading area in the juxtaposition condition is generally larger than that of the seriation condition, with the exception to a slight increase is observed toward the end. Upon the two raindrops fuse completely, the maximum liquid film thickness and the region with large liquid film thickness at the midline are larger in comparison with those in juxtaposition condition.
Multiscale bubble breakup dynamics adjacent to a blade in unsteady turbulence within a bubble breaker
Authors: Ji Junhong , Li Changqing , Xie Jing , Tang Zhexin
Published: January 2025

To comprehend the dynamic characteristics of multiscale bubbles in proximity to the propeller within unsteady turbulence, the large eddy simulation-fluid volume numerical method is employed to investigate the mechanisms of bubble fragmentation, coalescence, and ascent at varying sizes and stirring speeds. The findings indicate that the dispersion behavior of bubbles in the high velocity gradient region surrounding the blade is more pronounced than their ascent behavior. Regardless of bubble size, the formation speed of daughter bubbles is maximized at 350 rpm, with smaller bubbles exhibiting a tendency to break at elevated speeds. Coalescence of bubbles typically occurs in regions of negative pressure, driven by high velocity gradients and influenced by turbulent vortices. The ascent behavior of the bubbles is affected by the Eötvös (Eo) number and vorticity shedding, as they rise around the blade, gradually approaching and entering the main vortex area. The bubble fragmentation process is governed by the Weber number, which decreases with increasing bubble size. At 350 rpm, the critical Weber number remains constant at approximately 40, regardless of bubble size, indicating that 350 rpm is a stable crushing speed.
Effect of hydrodynamic wakes in dynamical models of large-scale fish schools
Authors: Zhou Ji , Seo Jung-Hee , Mittal Rajat
Published: January 2025

A novel hydrodynamic model of the wake of a swimming fish is developed and incorporated into a dynamical model of a fish school to explore the effect of hydrodynamics on the emergent behavior in schooling fish. The model incorporates well-established rules for attraction, alignment, and visual detection via a force-momentum balance in the surge, sway, and yaw directions, thereby allowing us to include the effects of body size, shape, and inertia into the dynamics of fish swimming in a plane. The key novelty of the model lies in the modeling of the hydrodynamics, which includes not only the potential flow induced by the body of the fish but also the vortex wakes generated by the fish. These hydrodynamic features, as well as the surge, sway, and yaw force coefficients, are parameterized via three-dimensional high-fidelity direct numerical simulations of a carangiform swimmer, thereby enabling a higher degree of realism in these models. The model is used to examine the effect of wake characteristics on the topology and movement of fish schools. The simulations indicate that these wake vortices lead to improved organization within the schools, especially in situations where the social forces are relatively weak.
Positivity-preserving pseudo arc-length method for solving extreme explosive shock wave flow field problems in hyperbolic conservation law equations
Authors: Li Kun , Ma Tianbao , Wang Chentao
Published: January 2025

Hyperbolic conservation law equation is a system of partial differential equations, which has the characteristics of hyperbolic type, and its solution will eventually evolve into a singular solution with strong discontinuity and weak discontinuity. In solving hyperbolic conservation law equations, in addition to eliminating or reducing the singularity of the equation, it is also involved in solving the problems of high density ratios, high pressure ratios, low densities, and low pressures in extreme explosive shock wave flow field. The numerical solution process often produces negative density, negative pressure, or negative internal energy, which in turn triggers nonlinear instabilities in the region of large gradients, eventually leading to termination of the computational procedure. To effectively solve the above difficulties and improve the robustness of the algorithm, this paper proposes a high-order accuracy pseudo arc length method (PALM) with positivity-preserving for solving hyperbolic conservation law equations. The core idea of the algorithm introduces arc length constraint equations to realize the smooth transition of physical quantities with large gradients in the original physical space in the computational arc length space, so as to eliminate or attenuate the singularity of the discontinuous solutions in the computational process. In the orthogonal pseudo arc length coordinate system, a new weighted essentially non-oscillatory-z scheme with a global smoothness indicator is used for high-order reconstruction, effectively addressing the issue of nonphysical oscillations caused by high-order schemes. In addition, the positivity-preserving limiter of the high-order pseudo arc length adaptive method in the arc length computational coordinate system is further constructed and proved, and the grid motion limiting strategy is designed, which greatly enhances the reliability and robustness of the algorithm. Finally, numerical test results show that the PALM effectively reduces numerical oscillations and achieves high-resolution capture of discontinuity problems.
Using Fourier Transform Infrared spectroscopy to produce high-resolution centennial records of past high-intensity fires from organic-rich sediment deposits
Authors: Ryan Rebecca , Dosseto Anthony , Dlapa Pavel , Thomas Zoë , Simkovic Ivan , Mooney Scott , Bradstock Ross
Published: January 2025

Background Current observational or instrumental records of past fires are historically limited, and information on fire characteristics tends to be confined to the recent past. Aims and methods Here, we reconstruct a record of high-intensity fire events that extends beyond the historical record using carbon (C) and nitrogen (N) content and Fourier Transform Infrared (FTIR) spectroscopy applied to swamp sediment deposits in the Blue Mountains of south-eastern Australia. Each site has a different fire history over the past 50 years, and the known fire record was used to corroborate fire signatures before extending the record. Key results FTIR spectra show an increase in the aromatic/aliphatic ratio for sediments corresponding to known fire events. Higher aromatic/aliphatic ratios suggest exposure to higher-intensity fire conditions. Conversely, the C and N content and C/N ratio show no association with known historic fire events. Conclusions Sediment deposition at one site recorded three major fire events during the past ~500 years. Sediments recording the most recent fire event show a more significant increase in the aromatic/aliphatic ratio, suggesting that this event burnt at a higher intensity than the previous two. Implications All sites show a promising extension of the existing fire record by decades to centuries.
California isolates
Authors: Dagostino Carmen
Published: January 2025

California is known for its linguistic diversity and the impact of longstanding language contact on
genetic classification (Mithun 2010, 2012, 2017; Golla
2011; Haynie 2012). Although two hypothetical ancient linguistic
groupings were proposed (Hokan and Penutian), several languages are still considered isolates. This chapter examines
phoneme inventories, lexical affixing patterns, verbal number (pluractionality), and switch-reference in California
isolates and non-isolates to identify a potential link between linguistic features and isolate status. Comparison of
neighboring languages reveals that these linguistic features spread across genetic boundaries in geographically
contiguous areas and should therefore be attributed to language contact rather than to isolate status. The comparison
further illustrates that isolates are affected by language contact in the same way as non-isolates.
Improved threshold voltage stability for GaN p-channel field effect transistors by hydrogen plasma treatment
Authors: Yue Huixin , Yu Guohao , Guo Bohan , Li Yu , Li Ang , Lu Shaoqian , Zhou Jiaan , Xing Runxian , Yang An , Hao Chunfeng , Jiang Jinxia , Zhang Yuxiang , Cai Yong , Zeng Zhongming , Zhang Baoshun
Published: January 2025

This work proposes a novel gate stack with hydrogen (H) plasma treatment to improve the stability of p-channel field effect transistors (p-FETs). The threshold voltage (V
TH) of this device is −4.82 V, achieving normally-off operation, with exhibiting an I
on/I
off ratio of 106 and a low off-state leakage current of −10−7 mA mm−1 at V
GS = 2 V. The H plasma-treated gate stack significantly stabilizes the V
TH of GaN p-FETs, exhibiting minimal variations of 0.14 V and 0.15 V under negative (−5 V) and positive (5 V) gate voltages, respectively. H plasma treatment technology optimizes the sub-gate interface and enhances the threshold voltage stability of the device, guaranteeing the stable application of p-FETs in logic circuits.
Influencing mechanism of temperature on the electric field distribution and interface charge accumulation in oil-pressboard insulation under DC voltage
Authors: Gao Chunjia , Ge Hao , Yuan Qing , Wu Juzhen , Cao Yanming , Tian Huidong , Qi Bo , Li Chengrong
Published: January 2025

The operational temperature regime of a transformer critically influences the electric field topography and the interface charge dynamics within the oil-pressboard insulation. Employing the Kerr electro-optical phenomenon, this manuscript delineates the development of a thermal-modulated electric field mapping apparatus for oil-pressboard insulation. Empirical analyses on the electric field and interface charges under variable thermal conditions revealed the following: 1) within the single-oil-spacing model, an escalation in temperature engenders an amplified electric field intensity in oil, a diminished interface charge density, an augmented disparity between the polarization charge density and the ascertained charge magnitude, and at 80 °C, the discerned interface charge polarity is antithetical to the polarization charge. Hereupon, an oil-pressboard equivalent charge paradigm predicated on the Schottky emission schema was posited. At 20 °C, Schottky emission accounted for 0.95% of the interface charge, primarily as polarization charge; at 80 °C, it rose to 60.11%, with Schottky-derived charge density increasing by a factor of 1713.4, indicating its dominance. (2) Pertaining to the double-oil-spacing model, an elevation in temperature to 80 °C transposes the electric field distribution in oil, and the equivalent charge polarity discerned at 60 °C and 80 °C is counter to that observed at 20 °C. This effect indicates that after thermal enhancement, the interface charge polarity in the oil-pressboard composite aligns with the Schottky injection charge polarity, inverting the electric field distribution in the oil. (3) The employment of oil-polytetrafluoroethylene model presents the far less influence exerted by Schottky charge injection, and furtherly ensure the influencing mechanism of temperature on electric field in oil-pressboard.
A non-Markov chain model of heterogeneous polymer dynamics for exploring relaxation and creep behavior
Authors: Xing Ziyu
Published: January 2025

The viscoelastic responses of polymers, such as relaxation and creep, are substantially influenced by their mechanical and rheological behaviors, which are governed by the dynamics of polymer chains. Soft polymers, distinguished by their complex and nonlinear mechanical characteristics, offer a broad spectrum of potential applications across diverse sectors. To address these complexities, this paper introduces the Rouse-Bueche-Zimm bead-spring model, predicated on an internal viscosity framework, to dissect the heterogeneous and non-Markovian dynamics of polymers. This model conceptualizes polymer chains as a series of beads and springs, utilizing a three-dimensional force balance equation in conjunction with the generalized Langevin equation. The analysis of internal viscosity enables an investigation into non-Markovian effects. The model incorporates heterogeneity by assigning different friction coefficients and potential functions to different beads. Employing scaling theory, non-affine behavior, and mode-coupling theory, analytical solutions are derived to encompass both heterogeneity and non-Markovian dynamics. Additionally, the study introduces a novel relaxation function, expressed as a hyperbolic cosine, to supersede the traditional exponential function. Comparative numerical analyses with experimental data from extant literature substantiate the enhanced adaptability of the proposed hyperbolic cosine relaxation function in comparison to its classical exponential predecessor.
Magnetic vortex: fundamental physics, developments, and device applications
Authors: Bhattacharjee Payal , Mondal Sucheta , Saha Susmita , Barman Saswati
Published: January 2025

A magnetic vortex is one of the fundamental and topologically nontrivial spin textures in condensed matter physics. Magnetic vortices are usually the ground states in geometrically restricted ferromagnets with zero magnetocrystalline anisotropy. Magnetic vortices have recently been proposed for use in a variety of spintronics applications due to their resistance to thermal perturbations, flexibility in changing core polarity, simple patterning procedure, and potential uses in magnetic data storage with substantial density, sensors for the magnetic field, devices for logic operations, and other related fields. The data storage and computing capabilities of vortex-based devices are highly integrated and energy-efficient, with low drive current requirements. Thus, a comprehensive understanding ranging from basic physics to real-world applications is necessary to realize these devices. This article provides an overview of the recent developments in our knowledge of magnetic vortices and computing and data storage technologies that are based on them. This thorough analysis aims to advance knowledge and awareness of the possibilities of vortex-based spintronic devices in modern technologies.
Comparison of flexible strain sensors based on liquid metals with different microchannel structures
Authors: Dong Tianyun , Zhang Chengjun , Zhao Jingwen , Ma Yucai , Chen Yi , Wang Juntao , Liu Liming
Published: January 2025

Flexible strain sensors based on fluid microchannels have been widely used in flexible electronics due to their excellent performance. However, the current research ignores the effect of different microchannel structures on the performance of flexible sensors, which is unsuitable for a specific practical application. Therefore, in this paper, sensors with microchannel of straight, wavy, and triangular structures were developed, and the performances of these sensors were compared from the results of simulation and experiment, respectively. The results show that the flexible strain sensors based on these three microchannels have extremely low hysteresis performance. Compared to the strain-stress hysteresis of the straight and wavy sensors, triangular sensors have the lowest hysteresis about 1.713%. Consistently, the triangular sensors also have the lowest hysteresis about 0.229% under strain–resistance response among these sensors. However, the straight sensors have the highest sensitivity among them. In different angles of the same microchannel group, the 180-degree wavy and 90-degree triangular sensors have the lowest hysteresis. Finally, the 90-degree triangular sensor was successfully used to detect the motion states of the human body and robotic finger. The research in this paper provides new ideas for choosing which microchannel of flexible strain sensors to be used in the field of wearable electronics.
Physics-informed deep learning with multi-resolution for ensemble prediction of lithium-ion battery health status
Authors: Hu Tian , Zhang Xin , Sun Jiankai , Wang Jiaxu
Published: January 2025

Accurate prediction of the health status is critical for the reliability and safety of lithium-ion batteries (LIBs). However, some methods do not consider physical information in battery capacity degradation and typically overlook the capacity regeneration phenomenon (CRP) in their predictions. In this study, a multi-resolution and ensemble prediction method based on physics-informed deep learning for LIBs status is proposed. Specifically, multi-resolution decomposition is performed on battery capacity degradation trends to analyze global and local features. Global degradation features are physically modeled and integrated into the deep learning model to enhance interpretability and prediction accuracy. Local features can reflect CRP, and ensemble prediction of both global and local features can enhance feature-capturing capability and prediction accuracy. Experimental results indicate that the mean absolute error and root mean square error of this method, for capacity prediction, is almost consistently within 0.01. The absolute error for remaining useful life prediction is nearly within 1 cycle, which validates the effectiveness and stability of this method for LIBs health status prediction.
Accurate binding energy database based on first-principles calculations for Monte Carlo simulations of aluminum-based alloy
Authors: Zhao Jia , Sugio Kenjiro , Maeda Yutaro , Zhai Sen , Sasaki Gen
Published: January 2025

The evaluation of binding energy in alloys is crucial for assessing structural stability and predicting new materials in design. Thus, calculating binding energy has become a central focus. Empirical potential functions provide computational efficiency and the ability to explore large-scale material systems without the need for high-performance computing resources. However, limitations such as reduced precision and restricted applicability to novel materials remain a challenge. To address this issue, a new method based on first-principles calculations is introduced to accurately determine the binding energy in vacancy-containing Al alloys. The study focuses on four binary alloys: Al–Si, Al–Zr, Al–Mg, and Al–Ti. The root mean square error is employed to evaluate the quality of this novel binding energy database, demonstrating that it achieves precision comparable to first-principles calculations within Monte Carlo (MC) simulations. The results confirm that this database successfully replicates the aging process in Al alloys while offering superior computational speed compared to first-principles calculations without compromising accuracy. This advancement significantly enhances the precision of atomic modeling, improving both predictive accuracy and computational efficiency for novel materials. Furthermore, this potential opens the door for broader applications in alloy design, paving the way for the discovery of new materials with optimized properties.
Electromagnetic wave propagation in pulsed surface wave sustained plasmas at atmospheric pressure
Authors: Chen Chuanjie , Carbone Emile , Li Shou-Zhe , Zhou Feng , Wang Rugang
Published: January 2025

In this work, a long surface wave plasma column is generated using high power pulse-modulated microwave power in argon at atmospheric pressure. The temporal evolutions of the electron density and temperature are diagnosed by optical emission spectroscopy. It is found that the emission intensity peaks correspond to the nodes of standing surface waves where the local electric field is reduced, rather than the antinodes, which is in contrast with that in low pressure discharges. The reasons for this behavior are discussed by considering the excitation balance of the excited levels of Ar I in the plasma. A standing surface wave pattern propagating with the movement of the ionization front in the plasma column, which plays the role of a discontinuity, is observed by means of microsecond time-resolved imaging. Another standing wave at the location of the launcher is also described which indicates that the region below the gap also acts as a discontinuity for the wave propagation. The formation of the propagating standing wave is discussed with respect to the wave propagation characteristics by using an electromagnetic (EM) model based on the propagation of the surface wave. This study underlines the fundamental differences in the EM wave/plasma interactions between continuous and pulsed surface wave discharges and provides new insights into the importance of the microwave applicator segment for a complete description of the plasma column formation.
Smoothed particle hydrodynamics for free-surface and multiphase flows: a review
Authors: Le Touzé David , Colagrossi Andrea
Published: January 2025

The smoothed particle hydrodynamics (SPH) method is expanding and is being applied to more and more fields, particularly in engineering. The majority of current SPH developments deal with free-surface and multiphase flows, especially for situations where geometrically complex interface configurations are involved. The present review article covers the last 25 years of development of the method to simulate such flows, discussing the related specific features of the method. A path is drawn to link the milestone articles on the topic, and the main related theoretical and numerical issues are investigated. In particular, several SPH schemes have been derived over the years, based on different assumptions. The main ones are presented and discussed in this review underlining the different contexts and the ways in which they were derived, resulting in similarities and differences. In addition, a summary is provided of the recent corrections proposed to increase the accuracy, stability and robustness of SPH schemes in the context of free-surface and multiphase flows. Future perspectives of development are identified, placing the method within the panorama of Computational Fluid Dynamics.
Increasing the sensitivity of Love wave MSAW sensors by magnetoelastic layer thickness variation
Authors: Mengue P , Hage-Ali S , Petit-Watelot S , Zhgoon S , Hehn M , Elmazria O
Published: January 2025

Increasing the magnetic field sensitivity is one of the major challenges in the study of magnetic surface acoustic wave (MSAW) sensors. In this paper, Love wave MSAW sensors are investigated in a Transmissive Single Port Delay Line (TSP-DL) configuration, on ZnO (700 nm)/Y-X LiNbO3. CoFeB (100 nm) or CoFeB(100 nm)/SiO2(3 nm)/CoFeB(100 nm) sensitive magnetoelastic layers are placed in the acoustic path between two electrically connected interdigital transducers. The fundamental Love wave on ZnO(700 nm)/ Y-X LiNbO3 presents a high electromechanical coupling coefficient (K
2), resulting in a high signal amplitude, which is favorable for delay lines performances. Additionally, shear waves are highly sensitive to the magnetic field due to the large ΔG effect in the magnetoelastic layers. A maximum frequency shift of 0.36% was achieved using a CoFeB(100 nm)/SiO2(3 nm)/CoFeB(100 nm) stack as the sensitive layer, with a high maximum magnetic sensitivity of 3630 ppm mT−1 (1482 kHz mT−1 at 410 MHz). This sensitivity is among the highest reported in the literature on magnetic SAW sensors.
Development of a novel multi-constriction superconducting magnetic flux concentrator and its application in magnetoresistance-superconducting composite magnetic sensors
Authors: Han Siyuan , Wu Yue , Xiao Liye , Jin Zhenhu , Chen Jiamin
Published: January 2025

Magnetoresistance-superconducting composite magnetic sensors, as highly sensitive weak magnetic sensors, have broad application prospects in fields such as magnetocardiography, magnetoencephalography, and high-precision non-destructive testing. Among these, the magnetic field gain of the superconducting magnetic flux concentrator (MFC) is a key factor affecting the magnetic field resolution of magnetoresistance-superconducting composite magnetic sensors. However, current superconducting MFCs face the issue of saturation in magnetic field amplification performance. This paper proposes a novel superconducting MFC structure that enhances the magnetic field gain of the superconducting MFC by adopting a multilayer stacked structure of constrictions. Finite element simulations reveal the impact of different constriction stacking structure parameters on the magnetic field amplification capability. Based on this, a TMR-superconducting multi-constriction composite magnetic sensor with a double-layer constriction stacked structure was prepared. Compared to conventional TMR-superconducting composite magnetic sensors, the magnetic field sensitivity increased by more than 1.7 times. This superconducting MFC realizes a magnetic field gain of nearly 350 in a small volume, which boosts the magnetic field detection performance of traditional TMR from nT level to pT level at low frequencies. The research presented in this paper contributes to the development of high-sensitivity magnetoresistive sensors.
Optimisation and loss analyses of pulsed field magnetisation in a superconducting motor with cryocooled iron cores
Authors: Wang Qi , Hao Luning , Zhang Hongye , Wei Haigening , Sun Guojin , Huang Zhipeng , Wu Yuyang , Hu Jintao , Coombs Tim
Published: January 2025

Thanks to their compact size, reduced energy losses, and enhanced power density, superconducting motors utilising high-temperature superconducting (HTS) materials are particularly appealing for propulsion systems such as those used in electric aircraft. Upon magnetisation, stacked HTS coated conductors are transformed into trapped field stacks (TFSs), which represent a key variant of trapped field magnets. TFSs offer a promising alternative to traditional permanent magnets, providing rotor fields for motor operation, particularly in synchronous machines. To date, there has been a lack of comprehensive investigation into the interaction between HTS TFSs and cryocooled iron cores, as well as the losses generated in iron cores during pulsed field magnetisation (PFM). Furthermore, the optimal magnetisation strategy for achieving the maximum trapped field in TFSs through PFM for motor applications remains an unresolved issue. To address these challenges, a 2D electromagnetic-thermal coupled numerical model was built using the finite element method and validated against experimental data. This model was employed to analyse a superconducting machine featuring TFSs as rotor magnets and cryocooled iron cores. This study introduces two key novelties. The primary novelty lies in identifying the optimal combination of pulsed current amplitudes and TFS layer numbers required to achieve maximum magnetisation fields. The secondary novelty involves evaluating the overall losses in both superconducting and non-superconducting components of the machine during PFM. This includes heat generation in various layers of the TFS and losses in the motor’s active materials, such as copper windings and iron cores. Additionally, two practical motor configurations were proposed, and two calculation methods using linear interpolation of iron losses and steel grades were introduced to estimate the iron losses for the studied iron material, M270-35 A. This pioneering study is expected to serve as a valuable reference for loss analyses and structural design considerations in developing superconducting machines.
Enhancing primordial B-mode detection: comprehensive delensing pipelines for improved sensitivity to r
Authors: Chen Wen-Zheng , Liu Yang , Li Siyu , Hu Bin , Li Hong
Published: January 2025

Recognizing the impact of contamination from weak gravitational lensing B-modes induced by
Large Scale Structure, we examine delensing methods to enhance sensitivity to the tensor-to-scalar
ratio r in primordial B-mode detection experiments. This study presents a realistic pipeline to
improve r constraints using foreground-cleaned maps with negligible residuals. The pipeline,
based on simulations, is adaptable for future experiments. We focus on two delensing approaches:
(1) subtracting the gradient-order lensing B-mode template, computed by convolving the E-mode with
the lensing potential, from the observed B-mode signal; and (2) remapping observations using the
estimated inverse deflection angle. For parameter constraints, we employ three models to reduce
r uncertainty and bias, finding consistent uncertainties across models, though biases vary due
to the multipole-dependence of the delensing fraction. We demonstrated this pipeline using
simulated observation maps from future CMB polarization experiments, which included current
representative ground-based small aperture telescopes (sub-1m), next-generation ground-based large
aperture telescopes (6m), and highly competitive future space-based medium aperture
missions (3m). Results show a delensing efficiency of 40% with the small-aperture telescope
alone, increasing to 65% when combined with the large-aperture telescope, and 80% with the
satellite mission. These lead to reductions in r uncertainty by 46% for ground-based and 63%
for space missions. The most promising method adds the lensing template B-mode as an additional
frequency channel, minimizing bias on r.
Unveiling galaxy pair alignment in cosmic filaments: A 3D exploration using EAGLE simulation
Authors: Sarkar Suman , Pandey Biswajit
Published: January 2025

We investigate how galaxy pairs are oriented in three dimensions within cosmic filaments
using data from the EAGLE simulation. We identify filament spines using DisPerSE and isolate
galaxies residing in filamentary environments. Employing a FoF algorithm, we delineate individual
filaments and determine their axes by diagonalizing the moment of inertia tensor. The orientations
of galaxy pairs relative to the axis of their host filament are analyzed. Our study covers diverse
subsets of filaments identified through varying linking lengths, examining how galaxy pairs align
with the filament axis across different spatial parameters such as pair separation and distance
from the filament spine. We observe a nearly uniform probability distribution for the cosine of
the orientation angle, which is nearly identical in each case. We also investigate the effects of
redshift space distortions and confirm that the probability distributions remain uniform in both
real space and redshift space. To validate our approach, we conduct Monte Carlo simulations using
various theoretical probability distributions. Our analysis does not reveal any evidence of
preferential alignment of galaxy pairs within cosmic filaments in hydrodynamical simulations.
New shape for cross-bispectra in Chern-Simons gravity
Authors: Christodoulidis Perseas , Gong Jinn-Ouk , Lin Wei-Chen , Mylova Maria , Sasaki Misao
Published: January 2025

Chern-Simons gravity is known to suffer from graviton ghost production during inflation, which suppresses the parity-violating power spectrum at scales relevant to cosmic microwave background observations. In this work, we show that allowing the initial conditions of inflation to deviate from the standard Bunch-Davies state can enhance parity-violating non-Gaussianity in the scalar-tensor cross-bispectra. Our results reveal a significant additional contribution to the cross-bispectra in the flattened configuration, offering a new avenue to constrain parity-violating gravity.
STIPS algorithm enables tracking labyrinthine patterns and reveals distinct rhythmic dynamics of actin microridges
Authors: Bhavna Rajasekaran , Sonawane Mahendra
Published: January 2025

Tracking and motion analyses of semi-flexible biopolymer networks from time-lapse microscopy images are important tools that enable quantitative measurements to unravel the dynamic and mechanical properties of biopolymers in living tissues, crucial for understanding their organization and function. Biopolymer networks are challenging to track due to continuous stochastic transitions, such as merges and splits, which cause local neighborhood rearrangements over short time and length scales. To address this, we propose the Spatio Temporal Information on Pixel Subsets algorithm to track these events by creating pixel subsets that link trajectories across frames. Using this method, we analyzed actin-enriched protrusions, or ‘microridges,’ which form dynamic labyrinthine patterns on squamous cell epithelial surfaces, mimicking ‘active Turing-patterns.’ Our results reveal two distinct actomyosin-based rhythmic dynamics in neighboring cells: a common pulsatile mechanism between 2 and 6.25 min period governing both fusion and fission events contributing to pattern maintenance, and cell area pulses predominantly exhibiting 10 min period.
Evaluation of objective methods for analyzing ipsilateral motor evoked potentials in stroke survivors with chronic upper extremity motor impairment
Authors: Mohan Akhil , Li Xin , Zhang Bei , Knutson Jayme S , Widina Morgan , Wang Xiaofeng , Uchino Ken , Plow Ela B , Cunningham David A
Published: January 2025

Objective:Ipsilateral motor evoked potentials (iMEPs) are believed to represent cortically evoked excitability of uncrossed brainstem-mediated pathways. In the event of extensive injury to (crossed) corticospinal pathways, which can occur following a stroke, uncrossed ipsilateral pathways may serve as an alternate resource to support the recovery of the paretic limb. However, iMEPs, even in neurally intact people, can be small, infrequent, and noisy, so discerning them in stroke survivors is very challenging. This study aimed to investigate the inter-rater reliability of iMEP features (presence/absence, amplitude, area, onset, and offset) to evaluate the reliability of existing methods for objectively analyzing iMEPs in stroke survivors with chronic upper extremity motor impairment.Approach: Two investigators subjectively measured iMEP features from thirty-two stroke participants with chronic upper extremity motor impairment. Six objective methods based on standard deviation (SD) and mean consecutive differences (MCD) were used to measure the iMEP features from the same 32 participants. IMEP analysis used both trial-by-trial (individual signal) and average-signal analysis approaches. Inter-rater reliability of iMEP features and agreement between the subjective and objective methods were analyzed (percent agreement-PA and intraclass correlation coefficient-ICC).Main results: Inter-rater reliability was excellent for iMEP detection (PA> 85%), amplitude, and area (ICC> 0.9). Of the six objective methods we tested, the 1SD method was most appropriate for identifying and analyzing iMEP amplitude and area (ICC> 0.9) in both trial-by-trial and average signal analysis approaches. None of the objective methods were reliable for analyzing iMEP onset and offset. Results also support using the average-signal analysis approach over the trial-by-trial analysis approach, as it offers excellent reliability for iMEP analysis in stroke survivors with chronic upper extremity motor impairment.Significance: Findings from our study have relevance for understanding the role of ipsilateral pathways that typically survive unilateral severe white matter injury in people with stroke.
Long-term performance and stability of implanted neural interfaces in individuals with lower limb loss
Authors: Petros Eileen , Miller Michael , Dunning Jeremy , Pinault Gilles , Tyler Dustin , Triolo Ronald , Charkhkar Hamid
Published: January 2025

Objective. High-density nerve cuffs have been successfully utilized to restore somatosensation in individuals with lower-limb loss by interfacing directly with the peripheral nervous system. Elicited sensations via these devices have improved various functional outcomes, including standing balance, walking symmetry, and navigating complex terrains. Deploying neural interfaces in the lower limbs of individuals with limb loss presents unique challenges, particularly due to repetitive muscle contractions and the natural range of motion in the knee and hip joints for transtibial and transfemoral amputees, respectively. This study characterizes the long-term performance of these peripheral nerve interfaces, which is crucial for informing design modifications to optimize functionality. Approach. We evaluated the longitudinal performance of 16-contact nerve cuffs and their associated components implanted in four participants with unilateral transtibial limb loss over five years. Key outcome measures included charge density at sensory thresholds and electrical impedance. Main results. Out of 158 channels (i.e. individual contacts within the nerve cuffs and their corresponding leads), 63% were consistently responsive, 33% were partially responsive, and 4% were non-responsive. Smaller connector assemblies and increased lead length near the cuffs significantly enhanced performance, with the final two participants demonstrating notably improved responses where 77% and 96% of channels were consistently responsive, respectively, compared to 50% and 6% in the first two participants. Significance. Overall, the implanted nerve cuffs showed robust stability in the residual limbs of highly active individuals with limb loss. Furthermore, employing strategies to reduce stress on transition points in the components significantly improved overall system performance.
Global stellarator coil optimization with quadratic constraints and objectives
Authors: Fu Lanke , Paul Elizabeth J. , Kaptanoglu Alan A. , Bhattacharjee Amitava
Published: January 2025

Most present stellarator designs are produced by costly two-stage optimization: the first for an optimized equilibrium, and the second for a coil design reproducing its magnetic configuration. Few proxies for coil complexity and forces exist at the equilibrium stage. Rapid initial state finding for both stages is a topic of active research. Most present convex coil optimization codes use the least square winding surface method by Merkel (NESCOIL), with recent improvements in conditioning, regularization, sparsity, and physics objectives. While elegant, the method is limited to modeling the norms of linear functions in coil current. We present QUADCOIL, a global coil optimization method that targets combinations of linear and quadratic functions of the current. It can directly constrain and/or minimize a wide range of physics objectives unavailable in NESCOIL and REGCOIL, including the Lorentz force, magnetic energy, curvature, field-current alignment, and the maximum density of a dipole array. QUADCOIL requires no initial guess and runs nearly

10
2

×

faster than filament optimization. Integrating it in the equilibrium optimization stage can potentially exclude equilibria with difficult-to-design coils, without significantly increasing the computation time per iteration. QUADCOIL finds the exact, global minimum in a large parameter space when possible, and otherwise finds a well-performing approximate global minimum. It supports most regularization techniques developed for NESCOIL and REGCOIL. We demonstrate QUADCOIL’s effectiveness in coil topology control, minimizing non-convex penalties, and predicting filament coil complexity with three numerical examples.
Generalized diffusive epidemic process with permanent immunity in two dimensions
Authors: Carvalho V R , Alves T F A , Alves G A , Alencar D S M , Lima F W S , Macedo-Filho A , Ferreira R S
Published: January 2025

We introduce the generalized diffusive epidemic process, which is a metapopulation model for an epidemic outbreak where a non-sedentary population of walkers can jump along lattice edges with diffusion probabilities

D

S

or

D

I

if they are susceptible or infected, respectively, and recovered individuals possess permanent immunity. Individuals can be contaminated with probability

μ

c

if they share the same lattice node with at least one infected individual and recover with probability

μ

r

, being removed from the dynamics. Therefore, the model does not have the conservation of the active particles composed of susceptible and infected individuals. The reaction-diffusion dynamics are separated into two stages: (i) Brownian diffusion, where the particles can jump to the neighboring nodes, and (ii) contamination and recovery reactions. The dynamics are mapped into a growing process by activating lattice nodes with successful contaminations where activated nodes are interpreted as infection sources. In all simulations, the epidemic starts with one infected individual in a lattice filled with susceptibles. Our results indicate a phase transition in the dynamical percolation universality class controlled by the population size, irrespective of diffusion probabilities

D

S

and

D

I

and a subexponential (power-law) growth of the epidemics in the percolation threshold.
Assessing the dosimetric effects of high-Z titanium implants in proton therapy using pixel detectors
Authors: Bălan C. , Granja C. , Mytsin G. , Shvidky S. , Molokanov A. , Chiș V. , Oancea C.
Published: January 2025

A rapid increase in the use of proton therapy for cancer treatment has been seen in the last decade due to its clinical advantages. Therefore, more and more patients with implants and other metallic devices will be among those who will be treated. This study experimentally examines the effect and changes in the delivered fields, using water-equivalent phantoms with and without titanium (Ti) dental implants positioned along the primary beam path. We measured in detail the composition and spectral-tracking characterization of particles generated in the plateau region of the Bragg curve towards the Sub-peak region using high-spatial resolution, spectral and time-sensitive imaging detectors with a pixelated array provided by the ASIC chip Timepix3. A 170 MeV proton beam was collimated and modulated in a polymethyl methacrylate (PMMA) block. Placing two dental implants behind the PMMA block, the radiation was measured using two pixeled detectors with silicon (Si) sensors. The Timepix3 (TPX3) detectors measured in detail particle fluxes, dose rates (DR) and linear energy transfer (LET) spectra for resolved particle types. Artificial intelligence (AI) based-trained neural networks (NN) calibrated in well-defined radiation fields were used to analyze and identify particles based on morphology and characteristic spectral-tracking response. The beam was characterized and single-particle tracks were registered and decomposed into particle-type groups. The resulting particle fluxes in both setups are resolved into three main classes of particles: i) protons, ii) electrons and photons, and iii) ions. Protons are the main particle component responsible for dose deposition. High-energy transfer particles (HETP), namely ions exhibited differences in both dosimetric aspects that were investigated: DR and particle fluxes, when the Ti implants were placed in the setup. The detailed multi-parametric information of the secondary radiation field provides a comprehensive understanding of the impact of Ti materials in proton therapy.
Numerical simulation and optimization of discharge chamber miniaturization for the double hollow cathode sputtering type metal ion source
Authors: Zhu Tingru , Wang Jinghui , Fu Dongpo , Zhao Weijiang , Cai Shixian , Zhang Caijie , Zhu Kun
Published: January 2025

The double hollow cathode metal ion source produces metal
elements by hollow cathode sputtering and has a high material
utilization rate. However, at present, a high magnetic mirror field
is generated by an electromagnet, which is huge in volume and the
edge field of a high magnetic mirror field seriously affects ion
extraction. Miniaturization of the discharge chamber is a feasible
method to solve this problem. In this paper, a two-dimensional fluid
model of the double hollow cathode discharge structure under
magnetic mirror field constraints is developed to study the double
hollow cathode discharge and ion sputtering. The results show that
the sputtering depth flux is formed above the sputtering voltage of
400 V. The evolution of the sputtering depth profile results from
the combined effect of the wall ion flux, spatial radial electric
field, and ion collisions. The location of the maximum ion
sputtering depth depends mainly on the energetic ions entering the
hollow cathode from the anode. The magnetic field and thermal
electron emission strongly correlate with the sputtering depth. A
small discharge chamber structure is proposed with a hollow cathode
length of 36 mm, which is 24 mm smaller than the ion source
established by Peking University in 2017, using a magnetic mirror
field of 1400 Gs at the center point, which can be realized in the
form of a permanent magnet. The electron density in the center of
the discharge chamber is 2.88 × 1021 m-3 and 99% of
the electrons are confined within a radius of about 3.7 mm.
MEOP based 3He polarization and injection system for experiments below 1 K
Authors: Rao T. , Barrón-Palos L. , Berkutov I. , Crawford C.B. , Golub R. , Huffman P. , Konieczny M. , Korobkina E. , Reid Austin , Salazar-Ángeles B. , Smith C. , Tat R. , Zanatta-Martínez T.
Published: January 2025

Metastability exchange optical pumping (MEOP) is a widely
used technique for producing polarized 3He. In connection with
an experiment to search for the electric dipole moment of the
neutron (nEDM) we have built a MEOP based 3He polarization and
injection system to prepare 80 % polarized 3He at room
temperature which will be injected into a ∼ 400 mK measurement
cell filled with superfluid 4He. We describe the polarization
and injection system, which is designed to allow for final
concentrations of 10-8–10-10 of 80% polarized 3He
in the superfluid filled measurement cell. Only ≈ 0.72%
polarization loss due to gradients is expected during injection
The CuboDAQ data acquisition system
Authors: Zaffaroni E. , Haefeli G.
Published: January 2025

CuboDAQ is a custom data acquisition system to read out
SiPM-based detectors. It features electronic boards to digitize the
SiPMs signal, an FPGA-based system-on-module board, the connectivity
to transmit the data to a central server, and all the software
necessary to operate them. The front-end is based on the TOFPET2
ASIC, produced by PETsys, connected to a custom board, featuring an
Enclustra Mercury SA1 module with a Cyclone V FPGA. Multiple boards
can be operated synchronously by distributing the clock and
synchronous reset signals from a central source. The system
features a complete software framework to calibrate and monitor the
detectors, to acquire and process data and to perform track
reconstruction. The CuboDAQ system performance has been evaluated
in different scenarios and can cope with sustained rates of above
4·106 hits/s, with
peaks of more than
7·106 hits/s. This
system has been employed for the readout of the SND@LHC detector at
CERN, a testbeam telescope and lab setups.