bluuebunny/crossref_metadata_2025 huggingface dataset:
A prediction model for in-line and cross-flow coupled vortex-induced vibration of a near-wall circular cylinder
Authors: Tao Mengmeng , Sun Xu , Han Peiyi
Published: January 2025

Proximity of seabed complicates vortex-induced vibrations of submarine pipelines. Empirical models are better in engineering problem than high fidelity simulations and experiments to some extent. Present paper aims to propose a model consisting of structure and wake oscillators to predict in-line and cross-flow coupling vibration of a near-wall cylinder. Based on phenomena, mechanisms, and data analysis, some hydrodynamics, namely vortex shedding frequency and time-varying/time-averaged lift/drag coefficients, are modeled by Reynolds number, thickness of boundary layer, and gap (G) between cylinder and wall. Model responses reflect effects of the wall on the cylinder's vibration successfully. When G/D drops from 2 to 1 (D is diameter of the cylinder), amplitudes decrease monotonously, and the maximum amplitude shifts to a smaller reduced velocity (Ur). Vibrations and resonant tend to start/end at a larger/smaller Ur, leading to narrowing lock-in regions. Time-averaged transverse displacements increase monotonously in whole, while streamwise displacements drop in the resonance regime. Trajectories are shapes of symmetric “8,” being similar to that of an isolated cylinder in free stream. There are some unique features when G/D decreases from 1 to 0.35. First peak of in-line vibration tends to disappear. Trajectories become asymmetric shape of “8” or oval because the cylinder tends to vibrate in approximating frequencies in 2 directions. With further researches on effects of wall proximity, improvements of hydrodynamics can be better to enhance model's rationality and accuracy. An accurate model is essential to analyze the safety and reliability of submarine pipelines suffering vibration.
Effects of the caudal fin morphology on the swimming performance of sharks
Authors: Chu Wenhua , Zhou Qiaoli , Yan Jifeng , Zhai Minghao , Zhang Xinyang
Published: January 2025

This study examined the impact of caudal fin morphology on shark swimming performance using a kinematic model derived from video data. Three shark species—the banded houndshark (Triakis scyllium) with a sickle-shaped caudal fin, the blue shark (Prionace glauca) with an asymmetrical crescent-shaped caudal fin, and the white shark (Carcharodon carcharias) with a relatively symmetrical crescent-shaped caudal fin—were selected for numerical simulation. The effects of caudal fin area (S) and caudal lobe asymmetry ratio (CLAR) on the swimming performance were analyzed. The results indicated that the white shark, with its symmetrical crescent-shaped caudal fin, exhibited superior propulsive performance compared to the other fin shapes. An increase in the caudal fin area enhanced the pressure difference, thereby improving thrust and lateral force coefficients. Specifically, as the caudal fin area increased from 0.0155 L2 to 0.0185 L2 and CLAR rose from 2.46 to 3.19, the thrust force increment gradually declined. Changes in CLAR influenced the caudal vortex shape and pressure difference, affecting propulsive and lateral force coefficients. A lower CLAR led to a higher thrust force, but excessively low CLAR reduced the pressure difference, decreasing thrust force by 1.7% when CLAR was 1.05 compared to 1.15. This study elucidates the relationship between caudal fin morphology and hydrodynamic characteristics, providing insights into fish behavioral studies related to caudal fin propulsion and serving as a reference for the optimized design of underwater bionic robot shapes.
Fast and accurate prediction of flow in multi-row cascade based on combined neural networks
Authors: Mao Yijun , Cheng Kang , Xu Chen , Liu Min , Shi Lei , Zhang Yongqi
Published: January 2025

This paper proposes a fast and accurate method for predicting multi-row cascade flow based on a framework of combined neural networks. The primary idea of this method is to decompose the whole-annulus of multi-row cascade into different types of sub-regions, and flow prediction surrogate models based on neural networks are constructed for these sub-regions in a rectangular computational domain by applying the coordinate transformation technique. The prediction surrogate models for each sub-region are then combined, and the continuity of flow at the interfaces among sub-regions is used to iteratively compute the whole-annulus flow in the multi-row cascade. The main advantages of the proposed method include reduced dataset generation cost and neural network training cost through spatial decomposition, as well as the ability to achieve fast prediction of whole-annulus flow in multi-row cascade by combining the neural network surrogate models of the sub-regions. The test case of a two-dimensional stator-rotor interaction indicates that the prediction time of the developed method is approximately 5% of that required for numerical simulation, with over 99% of the nodes in the flow field exhibiting a normalized absolute error of less than 0.05. This approach can be further extended to the fast prediction of three-dimensional flow in multi-stage turbomachinery.
Modeling the fluid dynamics of mitral valve for clinical applications and surgical mitral valve repair
Authors: Collia D. , Adams D. H. , Trivieri M. G. , Fayad Z. A. , Pedrizzetti G. , Pandis D.
Published: January 2025

The geometric properties of the mitral valve (MV), the valve controlling the inflow of blood to the left ventricle (LV), is a primary subject of study in clinical cardiology since its movements represent central points for differentiating physiological from pathological conditions. The ability of describing and modeling MV-LV dynamics is fundamental for improving MV repair surgical procedure. The realistic MV modeling is challenging for each individual patient because the mechanical properties of tissues are not accessible noninvasively, making a rigorous fluid–structure interaction approach not easily applicable in a clinical scenario. This study reformulates and extends a dynamic MV model for numerical simulation of LV flow based on diagnostic images recorded during clinical routine and compared it with in vivo recordings of the original valve obtained by highly accurate echocardiography which allowed the MV frame-by-frame recording. Results validate the model for clinical application and indicate that the dynamic of the MV during its opening and closure is primarily driven by the flow with negligible contribution from elastic resistance. The numerical model is then employed to provide preliminary analysis of the implications in terms of fluid dynamics of the corrective MV repair surgery. Results confirm that after mitral valve repair the regurgitant volume is drastically reduced, the intracavitary kinematic flow transit across the LV is restored to near-normal pattern but with substantial differences in terms of energetic terms and time course of hemodynamic forces. This study confirms the feasibility of integrating numerical models and clinical imaging technologies for clinical evaluation.
Mechanism of tandem cascade slot jet control for gas–liquid separation in multiphase pumps
Authors: Qiang Pan , Li Rennian , Han Wei , Fu You
Published: January 2025

The intermittent gas retention and blockage phenomenon observed in helical axial-flow multiphase pumps under high gas volume fraction conditions not only reduces pump efficiency but also poses significant safety risks to oil and gas transportation pipeline systems. Addressing this issue is critical for the widespread engineering application of such pumps. This study investigates the influence mechanism of slot jet control on gas–liquid separation phenomena and pump performance under high gas volume fraction conditions by examining the temporal and spatial evolution of slot jet sources and the principle of jet controlling flow field in tandem blade cascades. The findings reveal that there exists an optimal axial overlap that maximizes both pump head and efficiency. The optimal pump performance is achieved when the axial overlap is negative, with higher gas volume fractions shifting the optimal solution toward greater axial overlap. Additionally, under varying gas volume fractions, a circumferential overlap of 0.2 demonstrates the most significant performance improvement. The effectiveness of tandem cascade slot jets in mitigating gas-phase accumulation is influenced by jet flow rate and jet source pressure stability. As the impact of the front blade wake flow on the working surface of the rear blade varies, the blade work capacity is optimized at a circumferential overlap near 0.2.
Detuning of triad resonance induced by steady free-surface flow over rippled bottoms
Authors: Fan Jun , Tao Aifeng , Liu Jianhao , Wang Gang , Zheng Jinhai
Published: January 2025

Investigating the hydrodynamics of free-surface flow over rippled seabeds remains a key focus due to the presence of multiple underwater sandbars and ambient currents in coastal and estuarine regions. There has been growing interest in the free-surface responses induced by resonant wave-current-bottom interactions. These interactions have the potential to transfer the wave energy from ambient flow to free-surface waves along with their intensive instability behaviors. The intensive resonant behaviors are closely related to the resonant conditions. If the wave-current conditions deviate from the exact resonance (also called the detuning scenarios), the free-surface responses will be affected significantly. However, the kinematic responses of the detuning effects are still limited and need further investigation. In this study, the detuning effects are studied based on the theoretical analysis. Two typical detuning scenarios are analyzed, and the corresponding temporal evolution/spatial distribution solutions of the near-resonant conditions are derived. Then, the phase-resolved wave hydrodynamic numerical model based on the high-order spectral method is applied to calculate the detuning behavior for cross-validation with the theoretical solutions. Finally, the detuning behaviors under near-resonant conditions are analyzed to reveal the significant quantitative decline pattern of resonant wave amplitude and period.
Physics-informed graph neural network based on the finite volume method for steady incompressible laminar convective heat transfer
Authors: Zhang Haiming , Xia Xinlin , Wu Ze , Li Xiaolei
Published: January 2025

The rapid development of deep learning has significantly influenced computational studies in convective heat transfer. To facilitate broader applications of deep learning models in convective heat transfer, this paper proposes a physics-informed graph neural network based on the finite volume method (FVGP-Net) for unsupervised training and prediction of steady incompressible laminar convective heat transfer problems. In this model, mesh data generated by the finite volume method (FVM) are converted into graph data, preserving the mesh's topological properties. This conversion allows FVGP-Net to utilize a graph convolutional network for information aggregation, capturing both local and global flow features and enhancing the model's geometric adaptability and predictive performance. The model incorporates physical laws directly into its loss function, ensuring compliance to these laws without reliance on training data. Unlike traditional physics-informed neural networks (PINNs), FVGP-Net replaces automatic differentiation with FVM-based numerical differentiation, balancing training efficiency with prediction accuracy. Boundary conditions are handled in accordance with the FVM, ensuring that the model strictly satisfies these constraints. We validated FVGP-Net using representative test cases, also examining the effects of different initialization methods on model training. The results demonstrate that FVGP-Net achieves high accuracy in predicting incompressible laminar steady convective heat transfer. Compared to traditional PINNs, this model inherits the conservation properties of the FVM, enhancing velocity prediction accuracy in convective heat transfer problems by 70.03%. Furthermore, the application of transfer learning markedly accelerates training, achieving approximately 70% faster results compared to Xavier initialization.
Circularly polarized RABBITT on atomic shells with large orbital momentum
Authors: Kheifets Anatoli S
Published: January 2025

In light atoms, the technique of Reconstruction of Attosecond Bursts by Interference of Two-Photon Transitions (RABBITT), driven by circularly polarized radiation, enables a complete retrieval of ionization amplitudes in the XUV+IR regime, including their relative phases (Kheifets 2024 Phys. Rev. Res.
6 L012002). In this work, we extend this method to heavier atoms by conducting numerical simulations of circularly polarized RABBITT on the Kr 3d and Xe 4d atomic shells. The XUV ionization dynamics in these atoms differ markedly due to the presence of a ‘giant’ shape resonance in the

4
d
→
E
f

ionization channel of Xe, a feature absent in Kr. Nevertheless, when an IR photon is added to the XUV ionization, the results for Kr and Xe are surprisingly similar, with the ratio of absorption/emission matrix elements and their relative phases remaining close in value. Moreover, these ratios and phases show minimal variation even when the Xe atom is encapsulated within a C60 fullerene cage. In search for the Cooper-like minimum in the IR absorption amplitude ratios predicted in Ji et al (2024 J. Phys. B 57 235601), we extend our investigation to the Ce 4f shell where this minimum is indeed present.
Controllable frequency tunability in constriction-based spin Hall nano-oscillators for neuromorphic computing
Authors: TM Arunima , Fulara Himanshu
Published: January 2025

The capability to precisely tune auto-oscillation frequency in spin Hall nano-oscillators (SHNOs) holds great promise across diverse applications, from data communication to neuromorphic computing. This study systematically investigates the controllable frequency tunability of nano-constriction-based SHNOs across distinct operational regimes. Through the independent tuning of critical magnetodynamical parameters-effective magnetization (

μ
0

M

eff

) and magnetic damping (α)-we unveil varying impacts on frequency tunability with changes in out-of-plane (OOP) field strengths and constriction widths. At large OOP fields,

μ
0

M

eff

predominantly governs frequency tunability, yielding a current tunability of 1 GHz/mA-four times greater than observed at the lowest

μ
0

M

eff

. At low OOP fields, although we observe a remarkably high frequency-tunability of 4 GHz mA−1,

μ
0

M

eff

alters the onset of transition from a linear-like mode to a spin-wave bullet mode. In contrast, α primarily affects the threshold current with less impact on frequency tunability. Moreover, we demonstrate that M
eff-driven frequency tuning enables control over the mutual synchronization of SHNOs, mimicking synaptic-like interactions between artificial neurons. Our findings greatly extend the versatility of SHNOs for oscillator-based neuromorphic computing and provide key insights into the intricate auto-oscillation dynamics under varying OOP fields.
Role of spin–orbit coupling for the band splitting in α-Sb and α-Bi on SiC(0001)
Authors: Yaegashi Ken , Sugawara Katsuaki , Takahashi Takashi , Sato Takafumi
Published: January 2025

Monolayer atomic thin films of group-V elements have a high potential for application in spintronics and valleytronics because of their unique crystal structure and strong spin–orbit coupling. We fabricated Sb and Bi monolayers on a SiC(0001) substrate by the molecular-beam-epitaxy method and studied the electronic structure by angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. The fabricated Sb film shows the (√3 × √3)R30° superstructure associated with the formation of α-Sb, and exhibits a semiconducting nature with a band gap of more than 1.8 eV. Spin-resolved ARPES measurements of isostructural α-Bi revealed the in-plane spin polarization for the topmost valence band, demonstrating its Rashba-splitting nature due to the space-inversion-symmetry breaking. We discuss the origin of observed characteristic band structure and its similarity and difference between Sb and Bi.
Anomalous pumping in the non-Hermitian Rice–Mele model
Authors: Kumar Abhishek , Mazumdar Sarbajit , Mahanti S D , Saha Kush
Published: January 2025

We study topological charge pumping in the Rice–Mele (RM) model with irreciprocal hopping. The non-Hermiticity gives rise to interesting pumping physics, owing to the presence of skin effect and exceptional points. In the static one-dimensional (1D) RM model, we find two independent tuning knobs that can drive the topological transition, namely, non-Hermitian parameter γ and system size N. To elucidate the system-size dependency, we use a finite-size generalized Brillouin zone scheme to show that the edge modes can be distinguished from the non-hermiticity induced skin modes. Moreover, this scheme can capture the state pumping of topological edge modes as a function of γ in the static 1D RM model and it further provides insight into engineering novel gapless exceptional edge modes with the help of adiabatic drive. Furthermore, we show that the standard topological pumping due to the adiabatic and periodic variation of the model parameters survives even with finite γ. However, we observe that it depends upon the driving protocols and strength of the non-Hermiticity (γ). With increasing γ, the adiabatic pumping for non-trivial protocols is destroyed first and then re-emerges as an anomalous pumping which does not have any Hermitian counterpart. Additionally, we observe that even a trivial adiabatic protocol can give rise to pumping as opposed to the Hermitian system. This is attributed to the inherent point gap physics of non-Hermitian system which we explain by reformulating a non-Bloch topological invariant for the 1+1D RM model. This invariant explains the number of pumped charges (in each period) for all the driving protocols.
Combined feature of enhanced stability and multi-level switching observed in TiN/Ta2O5/Ag-NPs/ITO/PET structure
Authors: Hu Su , Jiang Kang’an , He Yunyang , Bao Peng , Su Nan , Zhao Xinhui , Wang Hui
Published: January 2025

Both stability and multi-level switching are crucial performance aspects for resistive random-access memory (RRAM), each playing a significant role in improving overall device performance. In this study, we successfully integrate these two features into a single RRAM configuration by embedding Ag-nanoparticles (Ag-NPs) into the TiN/Ta2O5/ITO structure. The device exhibits substantially lower switching voltages, a larger switching ratio, and multi-level switching phenomena compared to many other nanoparticle-embedded devices. We attribute it to the embedded Ag-NPs effectively switching the mechanism of conductive filaments and the controlled distribution of Ag-NPs facilitates the occurrence of multi-level switching. Additionally, the fabricated structure demonstrated an impressive optical transmittance of nearly 85%. Undoubtedly, this combined feature of RRAM not only enhances stability but also enables multi-level switching, thereby demonstrating an approach to fabricating versatile and practical electronic devices aimed at boosting storage capacity and speed.
Infrared photoresponse of GeSiSn p–i–n photodiodes based on quantum dots, quantum wells, pseudomorphic and relaxed layers
Authors: Timofeev V A , Skvortsov I V , Mashanov V I , Bloshkin A A , Loshkarev I D , Kirienko V V , Zalyalov T M , Lozovoy K A
Published: January 2025

Structural and photoelectric properties of p–i–n photodiodes based on GeSiSn/Si multiple quantum dots (QDs) both on Si and silicon-on-insulator substrates were investigated. Elastic strained state of grown films was demonstrated by x-ray diffractometry. Annealing of p–i–n structures before the mesa fabrication can improve the ideality factor of current–voltage characteristics. The lowest dark current density of p–i–n photodiodes based on QDs at the reverse bias of 1 V reaches the value of 0.8 mA cm−2. The cutoff wavelength shifts to the long-wavelength region with the Sn content increase. Maximum cutoff wavelength value is found to be 2.6 μm. Moreover, multilayer periodic structures with GeSiSn/Ge quantum wells and GeSiSn relaxed layers on Ge substrates were obtained. Reciprocal space maps were used to study the strained state of GeSiSn layers. The optimal growth parameters were determined to obtain slightly relaxed GeSiSn layers. Designed p–i–n photodiodes based on these structures demonstrated the minimal dark current density of 0.7 mA cm−2 and the cutoff wavelength of about 2 μm.
Generative adversarial networks with fully connected layers to denoise PPG signals
Authors: Avila Castro Itzel A , Oliveira Helder P , Correia Ricardo , Hayes-Gill Barrie , Morgan Stephen P , Korposh Serhiy , Gomez David , Pereira Tania
Published: January 2025

Objective.The detection of arterial pulsating signals at the skin periphery with Photoplethysmography (PPG) are easily distorted by motion artifacts. This work explores the alternatives to the aid of PPG reconstruction with movement sensors (accelerometer and/or gyroscope) which to date have demonstrated the best pulsating signal reconstruction. Approach. A generative adversarial network with fully connected layers is proposed for the reconstruction of distorted PPG signals. Artificial corruption was performed to the clean selected signals from the BIDMC Heart Rate dataset, processed from the larger MIMIC II waveform database to create the training, validation and testing sets. Main results. The heart rate (HR) of this dataset was further extracted to evaluate the performance of the model obtaining a mean absolute error of 1.31 bpm comparing the HR of the target and reconstructed PPG signals with HR between 70 and 115 bpm. Significance. The model architecture is effective at reconstructing noisy PPG signals regardless the length and amplitude of the corruption introduced. The performance over a range of HR (70–115 bpm), indicates a promising approach for real-time PPG signal reconstruction without the aid of acceleration or angular velocity inputs.
Characterization of a radiofrequency storage ion source using numerical simulations
Authors: Kumar Nanditha Sunil , N Vignesh , Kumar S Sunil
Published: January 2025

A radiofrequency ion source routinely employed for laboratory astrophysics and astrochemistry experiments designated as the storage ion source was characterized using numerical simulations. The present work focuses on optimizing the storage and extraction of ions of astrophysical relevance having the m / z range 3 − 330, which covers most of the molecular ions detected in the interstellar medium and circumstellar envelopes. The crucial parameters for the storage of ions: radiofrequency signal frequency, f

RF
and amplitude, V

RF
were optimized, and the range of radiofrequency parameters that can be used to store ions inside the source is presented. The lifetimes of ions inside the source were estimated for various radiofrequency parameters. The difference in the lifetimes of ions of different m / z was explained based on the ions’ thermalization characteristics and the source’s effective potential. The extraction of ions from the source was optimized, and a new design called the T-source was proposed to improve the extraction efficiency. We show that the T-source has better extraction efficiency than the original design, which is further enhanced by maintaining the source at a floating potential. Finally, we investigated the transmission characteristics of the extracted ions through a quadrupole ion guide, which may serve as an ion guide or a mass filter, leading to an ion storage device such as an ion trap or an ion storage ring.
Islands on codim-2 branes in Gauss-Bonnet gravity
Authors: Li Zhengjiang , Hong Zekai
Published: January 2025

We study the black hole information problem on codim-2 branes in Gauss-Bonnet gravity. Thanks to the island surface ending on the brane, the Page curve of eternal black holes can be recovered for all of the GB couplings within the causal constraints. Our results strongly support the universality of the island mechanism. Similar to Einstein’s gravity, the HM surface can exist only in a finite time in GB gravity. Remarkably, for various parameters, the maximum times of HM surface are always larger than the Page times. As a result, the strange behavior of HM surfaces does not affect the Page curves for general GB gravity. Finally, we establish the correlation between the Page time, GB couplings, and brane tension, revealing that the Page time increases with these factors.
Exact results on the number of gravitons radiated during binary inspiral
Authors: Chung Youngjoo , Yang Hyun Seok
Published: January 2025

We derive an exact formula F(e) which provides a concrete estimate for the total number and angular momentum of gravitons emitted during the nonrelativistic inspiral of two black holes.
We show that the function F(e) is a slowly growing monotonic function of the eccentricity 0 ≤ e ≤ 1
and F(1) = 1.0128 ⋯.
We confirm and extend the results obtained by Page for the function F(e). We also get an exact result for the ratio
ν (ei
) = 2ħN(Li
, ei
)/Li
where the numerator 2ħN(Li
, ei
) is the sum of the spin angular momentum magnitudes of the gravitons emitted and N(Li
, ei
) is the total number of gravitons emitted in the gravitational waves during nonrelativistic inspiral from an initial eccentricity ei
down to a final eccentricity e = 0 and the denominator Li
is the magnitude of the initial orbital angular momentum.
If the orbit starts off with unit eccentricity ei
= 1,
we get the value ν(1) = 1.002 268 666 2 ± 10-10 which confirms the Page's conjecture that the true value of ν(1) will lie between 1.001⋯ and 1.003⋯.
We also show that the formula F(e) for gravitons emitted, originally expressed as an infinite series, can be represented
by a single function through an integral representation.
Carbon emission responsibility accounting for all aspects of the power system based on carbon emission flow
Authors: Pan Juntao , Wei Xingqiu , Zhou Zhenglei , Li Jinjin
Published: January 2025

The development of low-carbon power is the only way for the power industry to achieve sustainable development. The development of low-carbon power needs to be based on the deepening of the understanding of carbon emissions in the power system. Based on the energy data and power flow calculation data, this paper uses the Newton-Raphson method to calculate the power flow of a given topology, combined with the carbon emission flow calculation theory. It obtains the necessary intermediate parameters of carbon flow calculation, such as the branch power flow distribution matrix, load distribution matrix, and injection distribution matrix. It finally uses the relevant methods to calculate the final carbon flow distribution results of the power system, so as to realize the carbon emission responsibility accounting of each link of the power system.
Selection of key indicators for comprehensive evaluation of smart distribution networks based on grey relational analysis
Authors: Tong Guoqing , Deng Qiangqiang , Yang Bing
Published: January 2025

To achieve an accurate comprehensive evaluation of smart distribution networks, it is necessary to scientifically select the key indicators for this evaluation. This paper proposes a method for screening the key indicators of a comprehensive evaluation of smart distribution networks based on grey relational analysis. First, based on the analysis of a large amount of data on the state and operation of smart distribution networks, 40 comprehensive evaluation indicators are selected from the dimensions of safety, reliability, intelligence, and economy. Then, using grey relational analysis, the importance of each indicator in the evaluation process of the smart distribution network is analyzed from the perspective of correlation degree, while excluding those indicators with lower correlation. This achieves the selection of key indicators for comprehensive evaluation. Finally, through grey relational analysis using actual historical operation data from a regional smart distribution network, indicators with low correlation, such as line overload rate (A4), outage energy loss (A5), 10 kV transformer overload ratio (A7), and proportion of distribution transformers with critical risks (A10) are excluded. The remaining high-correlation indicators verify the accuracy and scientific nature of the proposed method.
Arc fault detection method for DC microgrid based on multiple features
Authors: Chen Yong , Yang Ruixiong , Zeng Yingjie , Gao Shuping
Published: January 2025

DC microgrids can improve energy structure change and enhance the use of new energy sources. However, it is challenging to find series arcs in DC microgrid systems. In order to detect series arc faults in DC microgrids, this study suggests a multi-feature based approach. By calculating the standard deviation of the system arc current, the root mean square(RMS) of the d5 wavelet coefficients and the marginal spectral eigenfrequency amplitude, a triple fault criterion is constituted. Then the threshold comparison weighting method is utilized to achieve fault identification. Finally, the simulation verification of the triple-criteria-based DC microgrid fault arc detection method shows that the method proposed in this paper has good anti-interference and reliability.
A new load grouping control method for pumped storage power stations in the planning curve mode
Authors: Xu Lin
Published: January 2025

In order to enhance the role of pumped storage power stations in the grid for peak and frequency regulation, a new load grouping control method for pumped storage power stations in the planning curve mode is studied, and the algorithm process of early start-stop in the ramp smooth start-stop mode is proposed. The coordination control strategy with primary frequency regulation and the exception handling strategy are proposed in combination with this start-stop mode, and the effectiveness of the above method is verified based on the application of the Liyang Pumped Storage Power Station. It can be concluded that the smoothing effect of the start-stop process can be improved with the reasonable selection of the early start-stop time.
Numerical investigation of anion exchange membrane fuel cell with gradient anode gas diffusion layer
Authors: Song Nannan , Yuan Han , Hua Yanyou , Wu Jiarong , Tang Shuai , Zang Jiawang , Ou Xu , Pan Ji
Published: January 2025

A 2D model of an anion exchange membrane fuel cell (AEMFC) was presented in this paper, based on principles of mass conservation, species conservation, and charge conservation. The anode gas diffusion layer (GDL) was designed with a gradient in porosity along the direction of gas permeation to examine how this gradient porosity design affects cell performance and the internal transport of substances within the AEMFC. The findings indicate that anode GDL with gradient porosity distribution promotes a more uniform distribution of reaction gases and reduces the aggregation of liquid water on the anode side, thereby reducing the occurrence of anode flooding phenomenon. Additionally, the anode GDL with gradient porosity distribution enhances the membrane’s hydration levels, bringing an increased ion conductivity and improved overall AEMFC performance.
Emergency control technology for improving frequency safety of urban zoning power grid after disconnection
Authors: Zhang Tongzun , Chen Jialin , Shi Chenggang , Ni Zhenlin , Xiang Kai , Wang Yang
Published: January 2025

After the main grid of the urban power grid becomes unstable due to extreme disasters or attacks, if the partitioned power grid is disconnected and enters an off-grid state, it may cause a secondary drop in system frequency due to frequency voltage coupling and low penetration of new energy, resulting in power outages of important loads and adverse social impacts. Firstly, this article analyzes the frequency voltage coupling phenomenon and the adverse effects caused by the low penetration state of new energy after the disconnection of the partitioned power grid, and elaborates on the shortcomings of traditional emergency control measures for load shedding; Secondly, based on the extreme survival demand of the partitioned urban power grid, a frequency safety based load under-switching control technology is proposed, which reduces the amount of load shedding measures within the constraints of power grid frequency safety; Then, in response to the adverse effects of voltage frequency coupling and low penetration of new energy, an energy storage emergency control technology was proposed to enhance the transient frequency security of new energy after local grid disconnection. Combined with load under-switching control technology, a strong local grid disconnection frequency control strategy with multi-resource coordination was established. Finally, the effectiveness and feasibility of the emergency control strategy proposed in this paper were verified based on the regional power grid of a certain city in China.
Isolation switch state recognition method based on voiceprint recognition
Authors: Xie Xingsheng
Published: January 2025

Voiceprint recognition technology is used for identity verification and sound analysis by analyzing unique sound features such as frequency, rhythm, and fluctuation patterns. This technology is extended to industries like power grid monitoring, where it can automate the detection of the operational status of devices like scissor-type isolation switches. The paper explores the integration of voiceprint recognition with deep learning to automatically determine the posture of these switches, improving efficiency and reliability in power system operations. Additionally, machine vision is utilized for posture recognition based on images, further enhancing operational safety and automation in power grids.
Simulation study on steady-state temperature rise distribution of helical spring contact based on electric-thermo-mechanical coupling
Authors: Wang Lili , Ma Yongfu , Bao Zhenghong , Chen Yao , Ren Jiyun , Zhang Guohui
Published: January 2025

Thermal failures of busbar gas chambers in gas-insulated metal-enclosed switches (GIS) are common, and the failure points are usually the internal spring contacts. To study this phenomenon in depth, this paper constructs a 3D electrical-thermal-mechanical coupling simulation model of spring contacts, calculates the contact resistance and contact thermal resistance of the spring contact fingers by the Cooper-Mikic-Yovanovich (CMY) theory, investigates the distribution of temperature rise by considering the gravity of conducting rods, and performs thermal-fluid coupling simulation by the real circuit breaker model. The simulation results are consistent with the general characteristics of thermal failure of busbar spring contact fingers. This paper is of great significance for the investigation and analysis of the thermal failure of busbar gas chamber spring contact fingers and their structural optimization design.
Study of beam dynamic transient effects in the SARAF LEBT
Authors: Perry A. , Weissman L.
Published: January 2025

We study effects of transients on the beam transport in the SARAF Low Energy Beam Transport (LEBT) section. Beam signals from a collimator and a beam blocker at the LEBT exit were used for deducing the evolution of space charge neutralization during the beam pulse transport. The neutralization buildup time and final neutralization level were obtained. In the future, the impact of the varying neutralization level on the beam propagation downstream in the linac will be investigated.
BKT transitions of the XY and six-state clock models on the various two-dimensional lattices
Authors: Okabe Yutaka , Otsuka Hiromi
Published: January 2025

In a two-dimensional (2D) spin system, the XY model, characterized by planar rotational symmetry, exhibits a unique phenomenon known as the Berezinskii–Kosterlitz–Thouless (BKT) transition. In contrast, the clock model, which introduces discrete rotational symmetry, exhibits the BKT transition at two different temperatures due to this discreteness. In this study, we numerically investigate the BKT transition for XY and six-state clock models over various 2D lattices. We employ two primary methods: the Monte Carlo method, which analyzes the size dependence of the ratio of the correlation functions for two different distances, and a machine-learning approach to classify the different phases—namely, the low-temperature ordered phase, the intermediate BKT phase, and the high-temperature disordered phase. We identify the BKT transition temperatures for the XY and six-state models on honeycomb, kagome, and diced lattices. Combined with the previously calculated data for the triangular lattice, we then compare these values with the second-order phase transition temperatures of the 2D Ising model, for which exact solutions are known. Our results indicate that the ratio of the BKT transition temperatures for each lattice relative to the Ising model transition temperatures are close, although the values are not universal.
Feasibility of detecting non-small cell lung cancer using exhaled breath condensate metabolomics
Authors: Wang Sha , Chu Heng , Wang Guoan , Zhang Zhe , Yin Shining , Lu Jingguang , Dong Yuehang , Zang Xiaoling , Lv Zhihua
Published: January 2025

Lung cancer is one of the most common malignancy in the world, and early detection of lung cancer remains a challenge. The exhaled breath condensate (EBC) from lung and trachea can be collected totally noninvasively. In this study, our aim is to identify differential metabolites between non-small cell lung cancer (NSCLC) and control EBC samples and discriminate NSCLC group from control group by orthogonal projections to latent structures-discriminant analysis (OPLS-DA) models. The EBC differential metabolites between NSCLC patients (n = 29) and controls (n = 24) (20 healthy and 4 benign individuals) were identified using ultra-performance liquid chromatography-high resolution mass spectrometry based untargeted metabolomics method. The upregulated metabolites in EBC of NSCLC included amino acids and derivatives (phenylalanine, tryptophan, 1-carboxyethylisoleucine/1-carboxyethylleucine, and 2-octenoylglycine), dipeptides (leucyl-phenylalanine, leucyl-leucine, leucyl-histidine/isoleucyl-histidine, and prolyl-valine), and fatty acids (tridecenoic acid, hexadecadienoic acid, tetradecadienoic acid, 9,12,13-trihydroxyoctadec-10-enoic acid/9,10,13-trihydroxyoctadec-11-enoic acid (9,12,13-TriHOME/9,10,13-TriHOME), 3-hydroxysebacic acid/2-hydroxydecanedioic acid, 9-oxooctadeca-10,12-dienoic acid/9,10-Epoxy-12,15-octadecadienoate (9-oxoODE/9(10)-EpODE), and suberic acid). The downregulated metabolites in EBC of NSCLC were 3,4-methylenesebacic acid, 2-isopropylmalic acid/3-isopropylmalic acid/2,3-dimethyl-3-hydroxyglutaric acid, and trimethylamine-N-oxide. The OPLS-DA model based on 5 EBC metabolites achieved 86.2% sensitivity, 83.3% specificity and 84.9% accuracy, showing a potential to distinguish NSCLC patients from controls.
Ab-initio trained machine learning potential for MAX compound Ti2AlC: construction, validation, and study of non linear elasticity
Authors: Ghosh Aishwaryo , Moitra Amitava , Saha-Dasgupta Tanusri
Published: January 2025

One of the intriguing features exhibited by the layered MAX phase compounds, is the nonlinear elastic behaviour. Since the experimental observation of this curious behaviour, the underlying micro-mechanism has been discussed to interpret experimental observations. However, the theoretical investigation remained a challenge due to the associated length and time scales of the phenomena. In the present work, we adopt a data driven approach to develop a machine learned interatomic potential for the MAX compound Ti2AlC following the moment tensor potential protocol. The constructed potential is validated in lattice constant, formation energy, elastic constant, and stacking fault energies. Finally, applying machine learned potential in classical molecular dynamics provides a faithful representation of the experimentally observed nonlinear elasticity for Ti2AlC. The generated atomic configurations confirm the proposal of formation of ripplocations which allow atomic layers to glide relative to each other without breaking the in-plane bonds. We find common defects, like Al vacancy, strongly influence the hysteresis properties of the stress–strain curve, paving the route to defect-engineered nonlinear elasticity.
Investigating charge dynamics at lead halide perovskite single crystal surfaces
Authors: Kammlander Birgit , García-Fernández Alberto , Svanström Sebastian , Giangrisostomi Erika , Ovsyannikov Ruslan , Rensmo Håkan , Cappel Ute B
Published: January 2025

To further develop lead halide perovskites for their application in solar cells, understanding the material’s fundamental behavior under illumination is necessary. Investigating light-induced charge dynamics in single crystals can give insight into material inherent properties. Time-resolved photoelectron spectroscopy (TR-PES) allows to monitor the photovoltage build-up and decay between the sample surface and bulk over time and gives information on light-induced charge redistribution within the crystal. Additionally, this method enables us to follow compositional changes and surface degradation and distinguish these from purely electronic effects. Here we investigated the charge dynamics of two distinct lead halide perovskite single crystal surfaces (CsPbBr3, Cs-doped FAPbI3) using TR-PES in different timescales (ps to μs and s to min). It was found that CsPbBr3 shows photovoltage rise and decay on the nanosecond to microsecond time-range, which can be assigned to electron–hole pair separation between surface and bulk. On the other hand, such electron dynamics could not be resolved for Cs-doped FAPbI3 at these fast timescales. Instead, for Cs-doped FAPbI3, the observed photovoltage decay was dominated by much slower dynamics and relaxation to the dark equilibrium state took around 10 min. This suggests that ion migration is responsible for a photovoltage build-up between surface and bulk of the crystal.
Analysis and precision of a low cost GNSS receiver for georeference in cultural heritage and historic landscape for an HBIM environment
Authors: Moyano Juan , Nieto-Julián Juan E , Marín-García David , Fernández Valderrama Pedro
Published: January 2025

For the most part, government institutions recognize that cultural heritage is a source of unparalleled expression of humanity’s footprint over time and therefore must be adequately studied, managed, and preserved. To achieve this, and especially in the case of monuments and sites of cultural-historical interest, various techniques and methodologies are employed to facilitate the acquisition of precise geometric information and geographic location. In this context, the use of Global Navigation Satellite System (GNSS) receivers enables something as fundamental as connecting the digitally reconstructed heritage model with a geographic information system located in terrestrial space. Considering that low-cost GNSS receivers are currently emerging and improving these processes and their speed of execution, this study proposes a research framework where, through measurement techniques and knowledge of the limitations of experimental methods, the precision of a low-cost GNSS receiver is used as a measurement element to establish control points in photogrammetry using Unmanned Aerial Vehicles (UAVs). The results show that the Leica Zeno FLX100 intelligent device achieves a precision of around 0.015 metres, surpassing that of other consolidated Global Positioning System (GPS) devices on the market, and that this equipment is more operational and effective for establishing Ground Control Points (GCPs) in aerial photogrammetry flights due to its speed in recording data and sending it to operators. The experimental samples were collected in two work areas: rural and urban environments. Performance was measured in terms of accuracy and feasibility in the Building Information Model (BIM) environment. In a static-urban context, the differentials between both receivers were practically identical, except on the X axis. In a dynamic-rural context, the low-cost receiver produced better results than the comparison receiver.
Bridging the gap: A collaborative model for forensic social work dissemination and translation
Authors: Lattas Dimitra , Rock Jacoba
Published: January 2025

Forensic social workers play an integral role in upholding human rights and social justice in criminal and juvenile legal settings, including in policing, courts, corrections, forensic mental health, and treatment facilities. These practitioners have organizational and ethical responsibilities to provide research-based and empirically informed interventions. However, research has shown a disconnect between research and practice in social work, including in the forensic social work arena. This article explores dissemination and translation strategies as mechanisms to bridge the research–practice gap. Forensic social workers should support the development of knowledge through scientific research, but they should also be equipped to disseminate and translate research that will address complex needs seen in the criminal legal system and with system-involved communities at micro, meso, and macro levels. The proposed collaborative model positions dissemination and translation as strategies to uphold evidence-informed practice, with important implications for practice, education, and community contexts, including the geographic- and identity-based communities most involved in and affected by criminal and juvenile legal practices.
Enhancing life satisfaction among individuals receiving methadone treatment: The contribution of childhood experiences, personal variables, and therapeutic alliance with the social worker
Authors: Ben-Shlomo Shirley , Angel Maya , Werbeloff–Becker Nomi , Roska Paola
Published: January 2025

This study examines life satisfaction in individuals receiving methadone treatment (MT) at a public healthcare clinic in Israel, using an ecological perspective to assess multiple influencing factors. A total of 180 participants completed surveys on childhood parenting styles, sense of belonging, self-esteem, and therapeutic alliance with the social worker in the healthcare setting. High sense belonging and self-esteem, as well as a strong therapeutic alliance, were positively correlated with life satisfaction. Conversely, non-adaptive parenting styles were related to lower life satisfaction. Therapeutic alliance mediated the associations between self-esteem and sense of belonging to life satisfaction, underscoring the critical role social workers play in enhancing well-being. The importance of potential strategies to enhance life satisfaction and integration into society for individuals in MT within health and social care environments is discussed.