bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of water and confining pressure on fault slip behaviors and rupture propagation
Authors: Long Kun , Wu Lizhou , Zhang Zhenyu , Liang Zhiming , Liu Han , Liu Zhenjian
Published: March 2024

Pore fluid is ubiquitous within the Earth's crust and severely impacts shear rupture propagation and the slip behaviors of faults. We conducted triaxial experiments on sandstone to investigate the effects of crack damage, confining pressure, and water on fault slip behaviors and rupture propagation. Two loading configurations, conventional loading and increasing-amplitude cyclic loading, were conducted to compare the inelastic behavior and failure modes of sandstone samples. In addition to a macroscopic deformation and mechanical properties analysis, a noncontact optical scanner and magnetic resonance imaging technique were used to analyze the microstructural evolution of the sandstone. The results show that a higher confining pressure results in a more homogeneous fault plane. Fault slip behaviors can be divided into the slip-strengthening and slip-weakening stages. In the brittle regime, pore water reduces the brittle strength of rocks but does not induce different fault slip behaviors. When the confinement is high enough, rocks fail in the brittle–ductile transition regime where dynamic faulting is prohibited. In the brittle–ductile transitional regime, pore water enhances stabilization, and the slip behaviors distinctively differ from those occurring without water.
Effects of curved vanes on aerodynamic performance and flow structures in highly loaded tandem cascades
Authors: Luo Qiao , Luo Lei , Song Xuezhou , Du Wei , Yan Han , Wang Songtao , Zhou Xun
Published: March 2024

Combining tandem cascades and curved vanes can mitigate the separation in highly loaded compressor cascades. Flow loss mechanisms in curved tandem cascades are crucial for fundamental design and optimization. This study investigates the flow losses and vortex structures in curved tandem cascades with different curved angles and an original straight tandem cascade. Numerical simulations are conducted at variable incidence angles. The results indicate no consistent effect of curved angles on the aerodynamic performance of curved tandem cascades. The tandem cascade with a curved angle of 5° effectively reduces losses at all incidence angles, while the tandem cascade with a curved angle of 15° extends the critical incidence angle to 3°. The comparative analyses reveal that curved vanes increase spanwise pressure gradients, causing low-energy fluid near endwalls to move toward the midspan. The weighting coefficient of losses quantitatively describes that curved vanes weaken the trailing edge shedding vortices of both vanes and passage vortex while enhancing the end wall spanwise vortex of the front vane, thus affecting the loss distribution. Finally, this study innovatively applies topological analysis methods to curved tandem cascades, establishing the relationship between topological structures and vortex structures in corner regions of tandem cascades, which provides a valid research approach to reveal the vortex dynamics mechanisms of the loss distribution in tandem cascades influenced by curved vanes.
Experimental study on gas slippage effect in coal at different temperatures based on nuclear magnetic resonance
Authors: Yu Yina , Meng Zhaoping , Lu Yixin , Zhang Kun , Gao Zhenghua
Published: March 2024

Coalbed methane (CBM) can be recovered more effectively through heat injection mining. The slippage effect in coal becomes more significant as CBM is exploited, essential for maintaining consistent production of CBM wells. By “slippage effect,” we mean that gas molecules exhibiting non–zero velocity near the wall surface of coal pores, leading to higher gas permeability than liquid permeability. To explore the slippage effect and its control mechanism during heat injection mining, methane seepage experiments with constant effective stress were conducted under five different temperatures and seven pore pressures. An analysis was conducted on the mechanisms by which pore pressure and temperature affect gas slippage effect. Furthermore, the correlation between coal pore structure and the gas slippage effect was revealed using the nuclear magnetic resonance (NMR) technique. The results appear that, first, as pore pressure increases, the slippage effect is suppressed due to the influence of the average molecular free path, despite the positive impact of adsorption–induced matrix expansion. Second, as temperature rises, the average molecular free path and thermal expansion have a positive impact on gas slippage, while matrix shrinkage caused by desorption has a negative impact. The positive impact is stronger, resulting in a continuous enhancement of the slippage effect. Finally, a new slippage factor calculation based on NMR T2 distribution of micropores and transitional pores (<100 nm, T2 < 8.33 ms) was provided, and the method was verified by slippage factor fitted by permeability experimental data. The heat injection mining of CBM can be theoretically guided by the research results.
Hydrophobic effects on a solid sphere translating in a Brinkman couple stress fluid covered by a concentric spherical cavity
Authors: Alotaibi Munirah Aali , El-Sapa Shreen
Published: March 2024

In this study, a fluid flow with an incompressible axisymmetric steady couple stress translated through a porous media is analyzed between a hollow sphere and a concentric rigid sphere. In the permeable region, the flow field is regulated by Brinkman's equation. The slip and spin slip conditions are applied on both the rigid sphere and spherical cavity surfaces. Modified Bessel functions provide a systematic approach to the problem by utilizing the principle of a stream function. On the inner sphere, the wall correction factor that an incompressible couple stress fluid encounters is calculated. The effects of the slip, spin slip, coupling stress parameter, separation distance, and permeability parameter on the field functions and the normalized drag force are also graphically shown. The corresponding results are contrasted with the outcomes reported for particular cases of couple stress fluid and viscous fluid flow in two permeability-free concentric circles. Furthermore, graphs of the streamlines for various values of the relevant parameters have been included.
Experimental investigation on inter-particle settling dynamics of multiple spherical particles released side by side at intermediate Reynolds numbers
Authors: Liu Jieqing , Xiao Yang , Liang Dongfang , Zhang Pei , Wang Zhihao , Liu Jiaming , Zhang Taotao , Zhou Jian
Published: March 2024

The settling of solid particles in fluid constitutes a fundamental and crucial aspect with applications spanning various natural phenomena and engineering processes, including sediment transport and wastewater treatments. This paper delves into an experimental investigation aimed at comprehending the settling dynamics and self-organization of multiple spherical particles settling side by side at intermediate Reynolds numbers. The study employs an electromagnetic release device, previously developed for controlled settling of particles under gravity, ensuring simultaneous release with zero initial rotation and velocity. This research captures settling trajectories and provides insight into the flow fields surrounding particles by utilizing particle tracking and particle image velocimetry. The experiments systematically investigate the influence of the settling patterns, the flow fields, the velocities of particles, and their dependence on Reynolds number Re (Re = 52–258), the number of particles n (n = 3–8), as well as the initial spacing between particles l0* (l0* = 0–2). The results consistently reveal a left–right symmetry about the centerline in settling patterns, flow fields, and particle rotations across all values of n, l0*, and Re. The final settling pattern exhibits distinct shapes dependent on l0*: a “V” or “M” shape for l0* < 0.2, a “concave-downward” shape for 0.2 < l0* < 2, and a “straight-line” shape for l0* ≥ 2. The lateral spread of particles increases with time, particularly pronounced with smaller l0* and larger Re, attributed to strong repulsive forces between neighboring particles. Correspondingly, the maximum of horizontal velocities reduces from outside to inside and increases with decreasing l0* and increasing Re. The inner vortices are smaller than the outer vortices, which causes the lateral spread. The vertical spread increases with n but remains insensitive to Re. The average terminal settling velocities for all particles in the array are consistently smaller than those for single particles, as a portion of kinetic energy contributes to horizontal motions.
Experimental study on the surface wave mode of a liquid film under the coupling effect of acoustic oscillation and electric field
Authors: Ma Su-shuang , Yan Zi-yi , Zhao Run-jia , Wang Ping , Jia Bo-qi
Published: March 2024

This paper conducted an experimental study of a charged liquid film subjected to the coupling effect of acoustic oscillations and an electrostatic field perpendicular to the plane. The experimental system was established. Three different substances—de-ionized water, ionized liquid (BMIMBF4), and a 50 wt. % glycerin–water solution—were utilized to form the liquid film. An oscillator was employed to generate the acoustic oscillations, while the electrostatic field was produced by a high-voltage power supply. Both the increase in oscillating frequency and electric field intensity were observed to alter the surface waveform and elevate the surface wavenumber. Furthermore, the experimental findings align qualitatively with the previously established theoretical results.
The impact of well spacing on three-dimensional in situ extraction of oil shale using high-temperature air injection
Authors: Sun Tengfei , Liu Hao , Zhang Yang
Published: March 2024

To explore the impact of well spacing on the in situ high-temperature air injection for three-dimensional shale oil recovery, this study constructed six different well-spacing physical models of shale oil for investigation. By comparing factors such as temperature distribution, cumulative oil production volume, heating rate factor, and specific energy consumption per unit volume of shale oil among the six different well-spacing models, the influence of well spacing on the in situ high-temperature air injection for three-dimensional shale oil recovery was analyzed. The results showed that all six shale oil models exhibited a ripple pattern, advancing along the fractured fissures from the heating well to the production well. Model I, Model II, Model III, Model IV, Model V, and Model VI completed the full decomposition of the shale region at 2610, 1530, 1800, 3510, 4050, and 6660 days, respectively. The heating rate factor reached its peak at 1800, 900, 1440, 2340, 3240, and 3960 days. Model III had the lowest specific energy consumption per unit volume of shale oil, which was 905.41 kW/m3. Using Model III for three-dimensional shale oil injection with high-temperature air in situ recovery will shorten the heating time and reduce heat loss.
Numerical study of microscale gas pump based on surface acoustic waves
Authors: Kosyanchuk Vasily
Published: March 2024

The concept of microscale fluidic pump based on microchannel with surface acoustic waves (SAWs), propagating along one of its walls, has been extensively studied in the last decade with possible application to lab-on-chip projects. Meanwhile, any mentions of the application of such device to gas medium seem absent in the literature. The present paper aims to fill this gap by investigating the possibility of using microchannel with SAWs as a microscale gas pump. The numerical study is performed using the modification of the direct simulation Monte Carlo method. It was shown that the pumping effect occurs mainly in the area covered by SAW, while the upper layers of gas are almost still in average. The pumping effect demonstrates weak dependence on gas rarefaction, decreases with the SAW speed, and is lower for a low amplitude to channel height ratios. Finally, it is shown that the propulsion intensity in the open system decreases with a decreasing microchannel height, while the compression ratio in the closed system, on the contrary, increases.
Novel molecular resources for single-specimen barcoding of enigmatic crustacean y-larvae
Authors: Dreyer Niklas , Olesen Jørgen , Grygier Mark J. , Eibye-Jacobsen Danny , Savchenko Alexandra S. , Fujita Yoshihisa , Kolbasov Gregory A. , Machida Ryuji J. , Chan Benny K. K. , Palero Ferran
Published: March 2024

Despite discovery more than 100 years ago and documented global occurrence from shallow waters to the deep sea, the life cycle of the enigmatic crustacean y-larvae isincompletely understood and adult forms remain unknown. To date, only 2 of the 17 formally described species, all based on larval stages, have been investigated using an integrative taxonomic approach. This approach provided descriptions of the morphology of the naupliar and cyprid stages, and made use of exuvial voucher material and DNA barcodes. To improve our knowledge about the evolutionary history and ecological importance of y-larvae, we developed a novel protocol that maximises the amount of morpho-ecological and molecular data that can be harvested from single larval specimens. This includes single-specimen DNA barcoding and daily imaging of y-nauplii reared in culture dishes, mounting of the last naupliar exuviae on a slide as a reference voucher, live imaging of the y-cyprid instar that follows, and fixation, DNA extraction, amplification and sequencing of the y-cyprid specimen. Through development and testing of a suite of new primers for both nuclear and mitochondrial protein-coding and ribosomal genes, we showcase how new sequence data can be used to estimate the phylogeny of Facetotecta. We expect that our novel procedure will help to unravel the complex systematics of y-larvae and show how these fascinating larval forms have evolved. Moreover, we posit that our protocols should work on larval specimens from a diverse array of moulting marine invertebrate taxa.
From Barack Obama to Donald Trump
Authors: Lin Jennifer
Published: March 2024

Do Democrats and Republicans appeal to different sets of moral foundations in their national convention speeches?
Do they make efforts to frame their messages so that it is attractive to their base and moderate voters? This study examines the
moral appeals that political elites use to communicate to their supporters. I analyze speeches starting from the 2008 to the 2020
Republican and Democrat National Conventions to see if there are differences in appeals to Harm, Fairness, Ingroup, Authority and
Purity, which are tenets of the Moral Foundations Theory. I find that Republicans are more likely to appeal to Authority, and in
2020, Purity, while Democrats appeal mostly to Harm. Using qualitative content analyses, we see that both parties apply the moral
language favored by the other side in their convention speeches on top of making appeals to moral foundations that are favored by
their own base.
Eye-voice and finger-voice spans in adults’ oral reading of connected texts*
Authors: Nadalini Andrea , Marzi Claudia , Ferro Marcello , Taxitari Loukia , Lento Alessandro , Crepaldi Davide , Pirrelli Vito
Published: March 2024

The present paper investigates the interaction between eye movements, voice articulation and the movements of the
index finger dynamically pointing to a text line in oral finger-point reading of Italian. During finger-point
reading, the finger appears to be ahead of the voice most of the times, by a margin that is significantly modulated by the
distribution of phrasal and prosodic units in the reading text. Eye movements replicate the same effects on a different time
scale. The eye is ahead of both voice and finger by a wide margin (confirming evidence observed for English and German sentence
reading), while showing a tendency to re-synchronise with voice articulation at the right edge of strong prosodic units (sentence
boundaries). Our evidence suggests a multicomponent view of the time span between the eye/finger and the voice. The span is shown
to be the dynamic outcome of an optimally adaptive reading strategy, resulting from the interaction between
individual decoding skills, the reader’s phonological buffer capacity, and the structural complexity of a reading text. Proficient
readers modulate their span to compensate for the different timing between word fixation and word articulation, read faster, and
dynamically adjust their processing window to the meaningful, prosodic units of a text.
Building the centrosome: PLK-1 controls multimerization of SPD-5
Authors: Conduit Paul
Published: March 2024

Centrosome maturation relies on the assembly of an underlying molecular scaffold. In this issue of JCB, Rios et al. (https://doi.org/10.1083/jcb.202306142) use cross-linking mass spectrometry to reveal how PLK-1 phosphorylation promotes intermolecular SPD-5 self-association that is essential for scaffold formation.
Excitation and recombination studies with silicon and sulphur ions at an EBIT
Authors: Orban I , Mahmood S , Fritjof T , Lindroth E , Dong C Z , Rui J l , Xie L Y , Schuch R
Published: March 2024

Measurements of electron-impact excitation and recombination rate coefficients of highly charged Si and S ions at the Stockholm electron beam ion trap are reported. The experimental method was a combination of photon detection from the trapped ions during probing and subsequently extraction and time-of-flight (TOF) charge analysis of these ions. The TOF technique allows to measure recombination rate coefficients separately for every charge state, and together with the photon spectra of these ions also the excitation rate coefficients. In this paper, we present more details of the experimental procedure and summarize the experimental results in comparison with two different state-of-the-art calculations of recombination and excitation rates for Si10+–Si13+ and S12+–S15+ ions. One of these uses a relativistic configuration interaction approach (flexible atomic code) and the other is a relativistic many-body perturbation theory. A good to excellent agreement with both of them is found in energy and resonance strength for the investigated ions.
Mass spectrometric study of fast heavy-ion induced products on microdroplet surfaces
Authors: Kitajima Kensei , Majima Takuya , Tsuchida Hidetsugu
Published: March 2024

Fast heavy-ion collisions with molecules that constitute a liquid are fundamental to the field of radiation chemistry and its application to biology. However, although collision-induced physical and chemical processes in liquids have been extensively studied, the initial stages of such processes remain not fully understood because of their complex behaviors. Accordingly, our group has studied the initial reactions occurring in the vicinity of fast-ion trajectories in liquids by mass spectrometric analysis of the secondary ions ejected from microdroplet surfaces upon fast heavy-ion impacts. In this topical review, we present our recent experimental advances in secondary-ion mass spectrometry using microdroplets of water, alcohols, and amino acid solutions. Our findings demonstrate the complex physicochemical behaviors of positive and negative product ions and highlight the role of secondary electrons in the mechanisms of biomolecular damage triggered by fast heavy ions.
Enhanced positron acceleration driven by femto-second laser pulses irradiating structured targets
Authors: Chintalwad S , Krishnamurthy S , Ghosh S , Ridgers C P , Ramakrishna B
Published: March 2024

We have proposed a compact scheme for generating high-density and high-energy positrons by irradiating different shaped targets with an ultra-intense laser pulse, using 2D particle-in-cell simulations and numerical analysis. Our simulations show that the Breit–Wheeler process dominates positron production during laser-target interaction when a laser with an intensity of

4
×

10

23

 

W

cm

−
2

is used. We obtain a positron beam with an energy of 2.5 GeV and a total number exceeding 109, which is an improvement by two orders of magnitude compared to previous work with the same laser intensity. By using different shaped targets, we are able to generate a high-energy positron beam with low divergence. The yield of positron pairs depends on both the target and the laser parameters, and we have investigated how the shape of the target can enhance pair production and reduce divergence. Both of our analytical and simulation results demonstrate that this high-flux and low-divergence positron beam has direct applications in the field of medical and astro-physics that can be explored in the upcoming high intensity laser facilities.
Lateral semiconductor magnonics: an array of GaAs stripes atop the YIG layer
Authors: Martyshkin A A , Bublikov K , Beginin E N , Sadovnikov A V
Published: March 2024

In this work, we demonstrate the numerical and experimental research of the spin-wave transport in a structure composed of a gallium arsenide (GaAs) stripe lattice interfaced to an yttrium iron garnet layer. We show that this structure can be considered as an array of an infinite number of laterally coupled ferrite-semiconductor waveguides. We show that the surface wave properties for colinear propagation along the semiconductor stripes are similar to the waves in magnetic films with partial metallization. In addition, the properties of these surface waves depend on the electron concentration of the GaAs and thus may be tuned. With regard to the wave propagation at a certain angle to the GaAs stripe lattice, the Bragg resonance forms and the corresponding band gap depend on the angle between the wave to the stripes and on the GaAs electron density. The Brillouin light scattering technique was used to experimentally observe the spin-wave beam transformation, and microwave measurements support the numerical data and reveal the mechanism of the dip formation and widening of the frequency range in the spin-wave transmission. The proposed structure could be used as a reconfigurable metasurface and magnonic beam separation unit.
High-quality germanium growth on (111)-faceted V-groove silicon by molecular beam epitaxy
Authors: Mtunzi Makhayeni , Jia Hui , Hou Yaonan , Yu Xueying , Zeng Haotian , Yang Junjie , Yan Xingzhao , Skandalos Ilias , Deng Huiwen , Park Jae-Seong , Li Wei , Li Ang , El Hajraoui Khalil , Ramasse Quentin , Gardes Frederic , Tang Mingchu , Chen Siming , Seeds Alwyn , Liu Huiyun
Published: March 2024

High-quality and low-defect-density germanium (Ge) buffer layers on silicon (Si) substrates have long been developed for group IV and III–V devices by suppressing defect propagation during epitaxial growth. This is a crucial step for the development of highly efficient photonic devices on Si substrates. Patterned silicon substrates have increasingly been employed for their ability to restrict and hinder the motion of defects. In this work, we demonstrate the effectiveness of an optimised two-step growth recipe structure on a (111)-faceted V-groove silicon substrate with a 350 nm flat ridge. This strategy successfully reduces the threading dislocation (TD) density while growing a 1 μm Ge buffer layer via molecular beam epitaxy. As a result, a high-quality buffer is produced with a low TD density on the order of 107 cm−2 and a surface roughness below 1 nm.
Phase transition mechanism of CsPbI2Br perovskite films induced by moisture
Authors: Liu Yufei , Lin Jianting , Han Qiang , Yang Chenggang , Li Lin , Xiao Jianrong , Yi Rongnan , Liu Xiaoliang
Published: March 2024

The humidity stability and phase transition mechanism of the all-inorganic perovskite CsPbI2Br based on an optimized dual-source co-evaporation preparation process are investigated at the film interface level. It is found that the CsPbI2Br films annealed at 300 °C for several minutes exhibit a best crystallinity and photoelectric properties. The as-grown CsPbI2Br film is confirmed to be a α phase with a dark brown cubic crystal structure and an average visible transparency of 35.9%. But it will be transformed into its δ phase with a transparent orthorhombic crystal structure and an average visible transparency of 80.3% after a certain amount of moisture exposure. Compared with the α phase film, the electronic structure of the δ phase has also changed significantly with a VBM shift of about 0.32 eV to high binding energy. The results of AR-XPS show that the water molecules in perovskite CsPbI2Br after a moisture exposure only adsorb on the surface rather than penetrate the interior of the lattice. When water molecules adsorb on the lattice surface, halide ions should migrate towards the lattice surface due to their high hydration enthalpy, resulting in halide vacancies within the lattice and causing the reduction of energy barrier for phase transition from α phase to δ phase. So the CsPbI2Br film will transform from its α phase to δ phase induced by water vapor, and this phase transition will be reversed to some extent after another annealing.
The influence of a copper spacer on the magnetic properties of Pd/Co/Cu/Pd multilayers with perpendicular anisotropy
Authors: Acosta H S , Delavechia A , Figueiró B M , Viegas A D C , da Silva R B , Rigue J N , Harres A
Published: March 2024

The potential for technological applications of systems presenting perpendicular magnetic anisotropy is undeniable. With the advent of spintronics and the possibility to explore spin textures, such as skyrmions, in devices, it becomes fundamental to understand how to finely tune the magnetic properties of nanometric systems. In multilayered thin films, characteristics such as domain structure, saturation magnetization and perpendicular anisotropy may be tailored by modifying the interfaces. In the present study, the impact of a copper spacer of varying thickness on the magnetic properties of Pd/Co/Cu/Pd multilayers is investigated. The evolution of magnetization curves, domain patterns and magnetization reversal processes in terms of the spacers thickness are analyzed.
Comparative analysis of methane conversion: pyrolysis, dry and steam thermal plasma reforming
Authors: Essiptchouk Alexei , Miranda Felipe , Petraconi Gilberto
Published: March 2024

Methane reforming is gaining attention because of its potential to be converted into energy-dense fuels or high-value chemicals. In addition to the production of syngas (H2+CO), the utilization of CO2 can help reduce greenhouse gases. Water steam is typically used to increase the output of H2. This study evaluated the potential of thermal plasma technology to produce clean hydrogen, carbon monoxide, and carbon black from methane by applying a thermodynamic equilibrium model. A comparative analysis of three cases of methane processing (pyrolysis, dry reforming, and steam reforming) is presented to provide a comprehensive understanding of the potential of thermal plasma technology for methane conversion.
Chirality-selective topological magnon phase transition induced by interplay of anisotropic exchange interactions in honeycomb ferromagnet
Authors: Ni Jin-Yu , Zheng Xia-Ming , Wei Peng-Tao , Liu Da-Yong , Zou Liang-Jian
Published: March 2024

A variety of distinct anisotropic exchange interactions commonly exist in one magnetic material due to complex crystal, magnetic and orbital symmetries. Here we investigate the effects of multiple anisotropic exchange interactions on topological magnon in a honeycomb ferromagnet, and find a chirality-selective topological magnon phase transition induced by a complicated interplay of Dzyaloshinsky–Moriya interaction and pseudo-dipolar interaction, accompanied by the bulk gap close and reopen with chiral inversion. Moreover, this novel topological phase transition involves band inversion at high symmetry points K and K′, which can be regarded as a pseudo-orbital reversal, i.e. magnon valley degree of freedom, implying a new manipulation corresponding to a sign change of the magnon thermal Hall conductivity. Indeed, it can be realized in 4d or 5d correlated materials with both spin–orbit coupling and orbital localized states, such as iridates and ruthenates, etc. This novel regulation may have potential applications on magnon devices and topological magnonics.
ODDformer: odd–even de-stationary and decomposition techniques transformer for aircraft engine remaining useful life prediction
Authors: Yi Shuang , Han Xiaodong , Liang Binbin , Huang Guoxin , Li Wei
Published: March 2024

In the aerospace industry, accurately predicting the remaining useful life (RUL) of aircraft engines is critical to reduce maintenance costs and increase safety. Existing RUL prediction algorithms fail to account for global temporal factors, overlook the non-stationary nature of monitored data, and neglect critical trends and seasonal characteristics. These factors directly affect the sensitivity of the forecast model to changes in the system state. In light of this, this study introduces an innovative end-to-end deep learning model, called odd–even de-stationary and decomposition transformer (ODDformer), specifically designed for accurate RUL prediction. By incorporating global time embedding, our model demonstrates improved temporal awareness. We propose an innovative odd–even sequence normalization technique, enhancing data stability. Our method incorporates advanced odd–even de-stationary attention to capture crucial dynamic features, deepening model understanding of data evolution. Simultaneously, our channel-independent series decomposition modules extract reliable trend and seasonal features for each sensor. Finally, the two feature sets are fused to obtain the final prediction results. Experimental results on the N-CMPASS dataset demonstrate a 50.89% reduction in RMSE for ODDformer compared to the baseline and a 59.08% reduction for Score. Ablation experiments have validated the efficacy of these components. Our findings offer promising potential for improving tasks like fault diagnosis and anomaly detection in prognostics and health management.
An improved tracking method for bearing characteristic frequencies in the time-frequency representation of vibration signal
Authors: Chen Bin , Qi Chang , Yun Zexuan , Wang Hongyu
Published: March 2024

Rolling bearing is one of the most critical components for support and energy conversion in machines. The fault characteristic frequency (FCF) of time–frequency representation has received increasing attention in bearing diagnosis under variable speed conditions. However, FCF-extracted methods have poor adaptability to amplitude attenuation and noise interference due to local distortions or even transitions in the estimated instantaneous frequency ridges. Consequently, this paper proposes an improved FCF tracking method for variable speed bearing diagnosis. A strategy for locating distortion intervals is first developed using exponential smoothing and residual distribution. Subsequently, an advanced fast path optimization method, including peak map renewal and curve search optimization, is proposed to extract the ridges of interest. Finally, the probability density function of curve-to-curve ratios is designed to accurately identifying bearing faults. Simulation and experimental results demonstrate the effectiveness of the proposed method.
Frequency-modulated continuous-wave laser interferometry measurement method based on cross-correlation
Authors: Zhang Dengpan , Yan Mengchao , Li Gaochao , Wang Yongjie , Li Fang
Published: March 2024

Frequency-modulated continuous-wave (FMCW) laser interferometry technology holds significant potential for applications in the fields of ultraprecision manufacturing and high-precision sensing. This paper proposes a novel approach among current phase demodulation methods is based on cross-correlation to address the challenge of this technology. On the basis of nonlinear correction of a distributed feedback laser, the intercepted beat frequency signal was first preprocessed with Z-score signal normalization and a smoothing filter. Subsequently, the interference beat signal was subjected to processing using a correlation method to derive the correlation function. Finally, the phase difference between adjacent beat signals was determined by pinpointing the maximum value of the cross-correlation function, enabling accurate displacement demodulation. Experimental validation was performed by constructing an FMCW laser interferometric displacement measurement system. The results indicated that the standard deviation of the displacement error for the cross-correlation method was 2.41 nm during static measurements. Compared to conventional maximum-point method, the static measurement error of the cross-correlation method has been reduced by 1.43 times. In dynamic measurements in the 500 μm range, The measurement error of the cross-correlation method has been reduced by 6.04 times, avoiding the dynamic measurement positioning problem of conventional feature point demodulation methods and making the measurement results more accurate. This advancement holds substantial practical value in the realm of phase demodulation in laser interferometry.
An automated methodology for whole-body, multimodality tracking of individual cancer lesions
Authors: Santoro-Fernandes Victor , Huff Daniel T , Rivetti Luciano , Deatsch Alison , Schott Brayden , Perlman Scott B , Jeraj Robert
Published: March 2024

Objective. Manual analysis of individual cancer lesions to assess disease response is clinically impractical and requires automated lesion tracking methodologies. However, no methodology has been developed for whole-body individual lesion tracking, across an arbitrary number of scans, and acquired with various imaging modalities. Approach. This study introduces a lesion tracking methodology and benchmarked it using 23 68Ga-DOTATATE PET/CT and PET/MR images of eight neuroendocrine tumor patients. The methodology consists of six steps: (1) alignment of multiple scans via image registration, (2) body-part labeling, (3) automatic lesion-wise dilation, (4) clustering of lesions based on local lesion shape metrics, (5) assignment of lesion tracks, and (6) output of a lesion graph. Registration performance was evaluated via landmark distance, lesion matching accuracy was evaluated between each image pair, and lesion tracking accuracy was evaluated via identical track ratio. Sensitivity studies were performed to evaluate the impact of lesion dilation (fixed versus automatic dilation), anatomic location, image modalities (inter- versus intra-modality), registration mode (direct versus indirect registration), and track size (number of time-points and lesions) on lesion matching and tracking performance. Main results. Manual contouring yielded 956 lesions, 1570 lesion-matching decisions, and 493 lesion tracks. The median residual registration error was 2.5 mm. The automatic lesion dilation led to 0.90 overall lesion matching accuracy, and an 88% identical track ratio. The methodology is robust regarding anatomic locations, image modalities, and registration modes. The number of scans had a moderate negative impact on the identical track ratio (94% for 2 scans, 91% for 3 scans, and 81% for 4 scans). The number of lesions substantially impacted the identical track ratio (93% for 2 nodes versus 54% for ≥5 nodes). Significance. The developed methodology resulted in high lesion-matching accuracy and enables automated lesion tracking in PET/CT and PET/MR.
Hierarchical decomposed dual-domain deep learning for sparse-view CT reconstruction
Authors: Han Yoseob
Published: March 2024

Objective. X-ray computed tomography employing sparse projection views has emerged as a contemporary technique to mitigate radiation dose. However, due to the inadequate number of projection views, an analytic reconstruction method utilizing filtered backprojection results in severe streaking artifacts. Recently, deep learning (DL) strategies employing image-domain networks have demonstrated remarkable performance in eliminating the streaking artifact caused by analytic reconstruction methods with sparse projection views. Nevertheless, it is difficult to clarify the theoretical justification for applying DL to sparse view computed tomography (CT) reconstruction, and it has been understood as restoration by removing image artifacts, not reconstruction. Approach. By leveraging the theory of deep convolutional framelets (DCF) and the hierarchical decomposition of measurement, this research reveals the constraints of conventional image and projection-domain DL methodologies, subsequently, the research proposes a novel dual-domain DL framework utilizing hierarchical decomposed measurements. Specifically, the research elucidates how the performance of the projection-domain network can be enhanced through a low-rank property of DCF and a bowtie support of hierarchical decomposed measurement in the Fourier domain. Main results. This study demonstrated performance improvement of the proposed framework based on the low-rank property, resulting in superior reconstruction performance compared to conventional analytic and DL methods. Significance. By providing a theoretically justified DL approach for sparse-view CT reconstruction, this study not only offers a superior alternative to existing methods but also opens new avenues for research in medical imaging. It highlights the potential of dual-domain DL frameworks to achieve high-quality reconstructions with lower radiation doses, thereby advancing the field towards safer and more efficient diagnostic techniques. The code is available at https://github.com/hanyoseob/HDD-DL-for-SVCT.
Equivalent uniform aerobic dose in radiotherapy for hypoxic tumors
Authors: Chvetsov Alexei V , Muzi Mark
Published: March 2024

Objective. Equivalent uniform aerobic dose (EUAD) is proposed for comparison of integrated cell survival in tumors with different distributions of hypoxia and radiation dose. Approach. The EUAD assumes that for any non-uniform distributions of radiation dose and oxygen enhancement ratio (OER) within a tumor, there is a uniform distribution of radiation dose under hypothetical aerobic conditions with OER = 1 that produces equal integrated survival of clonogenic cells. This definition of EUAD has several advantages. First, the EUAD allows one to compare survival of clonogenic cells in tumors with intra-tumor and inter-tumor variation of radio sensitivity due to hypoxia because the cell survival is recomputed under the same benchmark oxygen level (OER = 1). Second, the EUAD for homogeneously oxygenated tumors is equal to the concept of equivalent uniform dose. Main results. We computed the EUAD using radiotherapy dose and the OER derived from the 18F-Fluoromisonidazole PET (18F-FMISO PET) images of hypoxia in patients with glioblastoma, the most common and aggressive type of primary malignant brain tumor. The 18F-FMISO PET images include a distribution of SUV (Standardized Uptake Value); therefore, the SUV is converted to partial oxygen pressure (pO2) and then to the OER. The prognostic value of EUAD in radiotherapy for hypoxic tumors is demonstrated using correlation between EUAD and overall survival (OS) in radiotherapy for glioblastoma. The correction to the EUAD for the absolute hypoxic volume that traceable to the tumor control probability improves the correlation with OS. Significance. While the analysis proposed in this research is based on the 18F-FMISO PET images for glioblastoma, the EUAD is a universal radiobiological concept and is not associated with any specific cancer or any specific PET or MRI biomarker of hypoxia. Therefore, this research can be generalized to other cancers, for example stage III lung cancer, and to other hypoxia biomarkers.
Dual-parameter stretchable, transferable mesh piezoresistive sensor for electronic skin detection of strain and temperature changes
Authors: Wang Chunhui , Xin Chaojie , Song Qihang , Wang Shuobang , Cheng Siyi , Shi Chao , Zhao Dongyuan , He Qingyuan , Zhang Jie , Chen Xiaoming
Published: March 2024

Wearable sensors integrating multiple functions have great potential in artificial intelligence and flexible electronics at this stage and can perceive various external stimuli with high sensitivity and accuracy, such as strain, stress, and temperature. However, because multiple parameters do affect each other and reduce the sensing performance, making a single device that can detect multiple functions simultaneously is a huge challenge. In this paper, a strain-temperature dual-parameter sensor is developed with a planar structure design and used poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) and multi-walled carbon nanotubes polymerization materials to prepare a micron-sized film. The influence of two-dimensional structures on sensing performance is explored through simulation, and a structure with large deformation is selected to improve the strain detection range. The sensor can detect static and dynamic strain signals, and can maintain good linearity and response speed below 100 ms within a large strain range of 20%. In addition, the sensor also exhibits good temperature detection capability, with a temperature sensitivity of 18.2 μV K−1 and the ability to detect static and dynamic temperature changes with long-term stability. Finally, the sensor is tested in some actual scenarios, reflecting that the sensor manufactured has the dual-detection ability, showing sensitive strain monitoring and temperature perception decoupled between the dual signals. The sensor is realized with circuit board acquisition and wireless communication, combining multi-channel applications. Our research provides a feasible method for constructing multi-parameter human-computer interaction sensors.
Conditionally integrable
PT
-symmetric hierarchies and near-Lax pairs of the KdV and KPII equations
Authors: Choudhury S Roy , Pecora Keri
Published: March 2024

Earlier work is generalized to obtain novel conditionally-integrable hierarchies of various

P
T

-symmetric, nonlinear partial differential equations. The Painlevé Test yields the possible integrable cases. These are labeled by the integer n, the order of the dominant pole in the Laurent expansion for the solution. For the

P
T

-symmetric Korteweg–de Vries (KdV) equation which has been considered earlier, further analysis using the extended homogeneous balance technique gives the near-Lax Pair. Next, a

P
T

-Symmetric hierarchy of (2 + 1) Kadomtsev-Petviashvili equations is considered. The Painlevé Test and Invariant Painlevé analysis in (2 + 1) dimensions yield special solutions and Bäcklund Transformations for the integrable cases.
Liquid level measurement using a single electrode capacitive sensor made of carbon nanotube-paper composite
Authors: Qian Zhongjie , Li Tianyi , Kim Shawn , Cheng Yu-Jen , Sakthivelpathi Vigneshwar , Chung Jae-Hyun
Published: March 2024

Liquid level measurements play a vital role in various fields, including environmental, industrial, and medical applications. While hydrostatic, optical, and ultrasonic sensors are commonly used for this purpose, capacitive sensors have also gained prominence. However, capacitive sensors have inherent limitations in terms of dynamic range and resolution. These sensors consist of a pair of electrodes with a gap, and the size of this gap directly affects the sensor’s dynamic range and resolution. Increasing the gap size enhances the dynamic range but compromises resolution. To overcome this challenge, a novel approach involving the investigation of a single-electrode capacitive sensor is presented. This sensor consists of using a carbon nanotube-paper composite (CPC), which offers unique advantages for measuring liquid levels with improved dynamic range and resolution. The sensing performance of the single-electrode sensor is evaluated in both conductive and non-conductive containers, ensuring its versatility and applicability in different scenarios. Furthermore, the study explores the implementation of a differential configuration for the single-electrode sensor. This configuration aims to enhance accuracy and stability, particularly in achieving femto-Farad level accuracy. By leveraging the potential of the single-electrode capacitive sensor, numerous applications such as liquid level sensing, immersible liquid level sensing, and rain sensing are demonstrated. This result holds potential for advancing liquid level measurement capabilities across various industries and opening up new opportunities for sensor applications.
Analysis of T-Orthogonal greedy algorithm in noisy measurement
Authors: Deep Sunder , Poumai Khole Timothy , Kaushik S K
Published: March 2024

We define the Tikhonov Orthogonal Greedy algorithm (T-OGA), a variant of the orthogonal greedy algorithm, to study the recovery of sparse signals from noisy measurements. We establish sufficient conditions for T-OGA to recover sparse signals via restricted isometry property (RIP) inherited from frames. We introduce various concepts such as match matrix, match vector, and residue vector to execute T-OGA. Various technical lemmas have been established to prove our main theorem. In the execution of T-OGA, we employ Tikhonov regularization with regularization parameter λ to solve the minimization problem for the N-sparse solution. In our main result, we proved that if a frame satisfies the RIP of order N + 1 with isometry constant τ and

(
τ
+
λ
)
<

1

3

N

, then T-OGA can recover every N-sparse signal in the atmost N iterations.
AxoDetect: an automated nerve image segmentation and quantification workflow for computational nerve modeling
Authors: Lloyd David A , Alejandra Gonzalez-Gonzalez Maria , Romero-Ortega Mario I
Published: March 2024

Objective. Bioelectronic treatments targeting near-organ innervation have unprecedented clinical applications. Particularly in the spleen, the inhibition of the cholinergic inflammatory response by near-organ nerve stimulation has potential to replace pharmacological treatments in chronic and autoimmune diseases. A caveat is that the optimization of therapeutic stimulation parameters relies on in vivo experimentation, which becomes challenging due to the small nerve diameters (2 

μ

m), complex anatomy, and mixed axon type composition of the autonomic nerves. Effective development of in silico models requires tools which allow for fast and efficient quantification of axonal composition of specific nerves. Current approaches to generate such information rely on manual image segmentation and quantification. Approach. We developed a combined image-segmentation and model-generation software called AxoDetect: a target- and format-agnostic computer vision algorithm which can segment myelin, endo/epineurium, and both myelinated and unmyelinated fibers from a nerve image without training. Main results. AxoDetect is over 10 times faster on average when compared with current automatic methods while maintaining flexibility through the use of tunable pixel threshold filters to detect different types of tissue. When compared to a distribution-based and a manually segmented model of the splenic nerve terminal branch 1, the model generated with AxoDetect had comparable threshold prediction and was able to accurately detect an increase in activation threshold caused by the addition of surrounding fat tissue to the modeled nerve. Significance. AxoDetect contributes to the acceleration of neuromodulation treatment development through faster model design and iteration without requiring training. Furthermore, the computer vision approach and tunable nature of the filters in our method allow for its use in a variety of histological applications. Our approach will impact not only the study of nerves but also the design of implantable neural interfaces to enhance bioelectronic therapeutic options.