bluuebunny/crossref_metadata_2025 huggingface dataset:
How much resources are reasonable to spend on radiological protection?
Authors: Engström A , Isaksson M , Javid R , Larsson P A , Lundh C , Wikström J , Båth M
Published: December 2024

In short terms, a society’s available resources are finite and must be prioritised. The more resources that are spent on radiological protection, the lesser resources are available for other needs. The ALARA principle states that exposure of ionising radiation should be kept as low as reasonably achievable, taking into account economic and societal factors. In practice, one of several approaches to determine what is considered as reasonably achievable is cost-benefit analysis. A demanding part of cost-benefit analysis is to decide on an α value, which stipulates the value of radiological protection. There are different conversion methods on how to convert societal costs into an α value. However, with the assistance of recent developments within both health economics and radiological protection room for improvements was found. Therefore, the aims of the present study were to develop a new conversion method (on how to convert societal costs into an α value) and to provide recommendations of α values for each member country of The Organisation for Economic Co-operation and Development (OECD). With the help of systematic reviews of societal costs (the value of a statistical life, productivity losses and healthcare costs) and discount rates, as well as Monte Carlo simulations of the number of years between exposure and cancer diagnosis, a new conversion method and recommendations of α values could be presented. The new conversion method was expressed as a discounted nominal risk of exposure with a median (interquartile range) of 175 (136–222) per 10 000 persons per Sv for the public and 169 (134–207) per 10 000 persons per Sv for workers. For OECD in general, recommendations of α values were determined to be $56–170 per man.mSv for the public and $61–162 per man.mSv for workers (2023-USD).
A lightweight and rapidly converging transformer based on separable linear self-attention for fault diagnosis
Authors: Yin Kexin , Chen Chunjun , Shen Qi , Deng Ji
Published: December 2024

Reaching reliable decisions on equipment maintenance is facilitated by the implementation of intelligent fault diagnosis techniques for rotating machineries. Recently, the Transformer model has demonstrated exceptional capabilities in global feature modeling for fault diagnosis tasks, garnering significant attention from the academic community. However, it lacks sufficient prior knowledge regarding rotation invariance, scale, and shift, necessitating pre-training on extensive datasets. In comparison, contemporary convolutional neural networks exhibit greater ease of optimization. This limitation becomes particularly evident when applying the Transformer model in fault diagnosis scenarios with limited data availability. Moreover, the increasing the number of parameters and FLOPs. Pose a challenge to its suitability for mobile services due to the limited computational resources available on edge devices. To mitigate these issues, this paper introduces a novel lightweight Transformer (SepFormer) based on separable linear self-attention (LSA) for fault diagnosis task. The SepFormer performs a novel sequence-level feature embedding to better leverage the inductive bias inherent in the convolutional layers. Furthermore, it integrate a novel separable LSA mechanism into the Transformer architecture, effectively mitigating the computational burden concerns and significantly enhancing the training convergence speed. Extensive experiments are conducted extensively on a bearing fault dataset and gear fault dataset. The experimental results demonstrate that the SepFormer achieves a top-1 accuracy exceeding state-of-the-art approaches by more than 5%, while utilizing the fewest FLOPs. Moreover, the optimizability of SepFormer surpasses that of CNN, ensuring its superior preservation of inductive bias.
Detection of group-housed pigs feeding behavior using deep learning and edge devices
Authors: Gong Junjie , Deng Minghui , Li Guiping , Zheng Piaoyi , Yin Yanling
Published: December 2024

The detection of feed behavior at pig farms is essential in monitoring the welfare and health of pigs. Addressing the low automation level of feeding behavior detection in group-housed pig farming, this study proposes a lightweight feeding behavior detection model, GAB-YOLO, based on YOLOv8s. The model employs GhostNet with a Convolution and Self-Attention Mixed Module as the backbone, enhancing feature extraction capability while reducing parameters. Wise-IoU is utilized as the bounding box loss function to improve sensitivity to piglets. To integrate features of pigs with different body types, a feature fusion module called Bi-directional Multi Feature Pyramid Network is proposed as the neck part of the model. Experimental results demonstrate that the improved model achieves detection accuracies of 98.40% for drinking behavior and 98.66% for eating behavior in group-housed pigs, representing improvements of 2.79% and 2.99%, respectively, over the original YOLOv8s algorithm, with a 14.5% reduction in parameters. The Deep Simple Online and Realtime Tracking (DeepSORT) algorithm is integrated into the improved model to address the issue of inaccurate video behavior judgment by YOLO, forming the lightweight model GAB-YOLO-DeepSORT. Finally, GAB-YOLO-DeepSORT is deployed on the NVIDIA Jetson Nano. The practical operation on the Jetson Nano shows that the proposed model can track multiple targets for pigs of different sizes and varieties in a group-housed environment, thus ensuring the accuracy of pig feeding behavior recognition and providing support for the subsequent establishment of pig health systems.
Uncertainty evaluation for dynamic observations of unknown models based on mixture density network
Authors: Jiang Wen–Shu , Zhang Cheng–Yao , Cheng Zhen–Ying , Li Rui–Jun
Published: December 2024

Uncertainty of dynamic observations is an important indicator for characterizing the accuracy of dynamic measurements. However, the accuracy and reliability of dynamic observations with unknown models are difficult to characterize accurately using existing methods. An uncertainty evaluation method for dynamic observations based on mixture density network (MDN) is proposed. MDN is formed by combining the forward network with the Gaussian mixture model, which is appropriate for describing complex distributions. The radial basis function was used to construct the network and estimate the model parameters. The effectiveness of the MDN model is verified by processing simulated time series and experimental data. First, the uncertainties of three kinds of time series were evaluated based on the MDN model. Second, MDN was used to evaluate the uncertainties of dynamic observations for a contact probe, and the coordinate values were used as the network input to predict the change trend of the measured signals. The reliability of the proposed method was verified by comparing it with the Guide to the Expression of Uncertainty in Measurement and Monte Carlo methods.
A pitting fault diagnosis method for planetary gears in automatic transmission based on multiple advantageous sub-band signal fusion
Authors: Gong Ran , Chen Chen , Zhang Jinle , Li Jinxiao , Zhang Ximing
Published: December 2024

Localized pitting in planetary gears is a critical fault in the automatic transmission (AT) systems of heavy-duty vehicles, and identifying this fault is an important aspect of vehicle maintenance. A single sensor often fails to capture comprehensive fault information from the housing of the AT. To fully capture fault characteristics from multi-sensor data and improve the accuracy of intelligent fault diagnosis, this paper proposes a pitting fault diagnosis method based on the fusion of multiple advantageous sub-band signals. Initially, the proposed method employs variational mode decomposition based on K-optimization to demodulate the raw fault signals acquired by various sensors. Subsequently, the advantageous sub-band signals, which contain the pitting fault information, are selected by integrating two indices: variance accounted for and spectral entropy (H(F)). These selected sub-band signals are then fused using a data fusion method based on the dissimilarity measure. Finally, a 1D-AlexNet model is constructed to diagnose the fused signals. The validity and superiority of this method are confirmed through a pitting fault injection experiment on an AT test rig. This paper also compares other diagnosis methods to further demonstrate the superiority of the proposed method.
DE-RGBD SLAM: enhancing static feature point selection in RGB-D visual SLAM using depth information
Authors: Wu Moudong , Zheng Qingchun , Ma Wenpeng , Zhu Peihao , Yang Bin
Published: December 2024

Feature point extraction plays a key role in visual simultaneous localization and mapping (SLAM) systems. And it remains a major challenge to accurately select static feature points in a complex dynamic environment. To address this issue, this paper proposes an RGB-D SLAM method, referred to as DE-RGBD SLAM, which optimizes feature selection by integrating depth information and effectively utilizes depth data and multi-view geometric information to achieve localization and navigation for mobile robots in dynamic environments. Firstly, the method analyzes prominent feature regions in the image based on color and depth information captured by an RGB-D camera. It sets adaptive FAST corner detection thresholds according to the grayscale information of these regions while masking other areas. Next, the method obtains in-depth information on the detected feature points in the current frame. It combines their pixel coordinates in the image coordinate system to determine the presence of redundant feature points. Notably, the method can detect some dynamic feature points between consecutive frames. Subsequently, in the camera coordinate system, the method compares the depth information of feature points in the depth image with the epipolar depth estimates derived from the essential matrix to determine whether the features are static and eliminate dynamic feature points. This approach significantly enhances the reliability of static feature points. Finally, the accuracy and robustness of the proposed method are validated through experiments conducted on the public TUM dataset and real-world scenarios compared to state-of-the-art visual SLAM systems.
Direct assessment of the influence of pose repeatability on the accuracy of dimensional measurements for computed tomography systems with high degrees of freedom
Authors: Butzhammer Lorenz , Handke Niklas , Wittl Simon , Herl Gabriel , Hausotte Tino
Published: December 2024

Industrial x-ray computed tomography (CT) systems with high geometric flexibility are increasingly utilized for large-scale measurement objects or challenging measurement tasks. To maintain high accuracy when deviating from the established circular scan trajectory, trajectory calibration methods using multi-sphere reference objects with known marker positions are commonly employed. These multi-sphere objects can either be scanned together with the measurement object (online trajectory calibration) or in a separate scan (offline trajectory calibration). While offline calibration increases machine time, it generally results in higher scan quality. However, a sufficient pose repeatability is necessary to ensure comparable or even superior accuracy to online calibration. In this contribution, we present a straightforward procedure to compare both types of trajectory calibration in a way that the differences of the results can directly be traced back to the influence of the pose repeatability. The multi-sphere reference object is not only used for trajectory calibration, but simultaneously as a measurement object for repeated measurements. The methodology is tested on both a twin robotic CT system and a conventional CT system that is additionally equipped with a hexapod manipulator for adaptive object tilting. Results showed, independent from the type of trajectory calibration, systematic measurement errors in the order of 10−5–10−4 of measured sphere distances and sphericity values below 50

μ

m

. For sphere distances, random errors were increased by a factor of 5 due to the offline trajectory calibration, but were still low (

<

1

μ

m

) in comparison to systematic errors and the spread of different measurement features. Overall, both investigated systems demonstrated sufficient positioning repeatability for offline trajectory calibration. The method is in general also applicable to any other types of manipulator systems used for CT devices. It provides a workflow for the decision which type of trajectory calibration is preferable for a given CT system.
Implementation of a long-wavelength model for parallel magnetic fluctuations in the global GENE code
Authors: Sheffield F , Görler T , Wilms F , Merlo G , Jenko F
Published: December 2024

A long-wavelength model for the turbulent magnetic fluctuations parallel to the magnetic field (

B

1
,

|

|

) has been implemented in the global gyrokinetic code GENE. The model provides a way to include this physical effect with little computational cost, permitting the study of

B

1
,

|

|

on global nonlinear gyrokinetic simulations. The model has been verified through convergence tests and against an arbitrary wavelength solver, resulting in good performance up to moderately high wavelengths (

k
y

ρ
s

≲
1

). Using this approximation global nonlinear fully electromagnetic simulations were performed with Cyclone Base Case-like parameters to study the impact of

B

1
,

|

|

on different plasma β regimes. A negligible impact for a low beta regime and roughly a doubling of the heat transport when including

B

1
,

|

|

in a high beta KBM regime is found, which is in line with expectations based on linear studies and highlights the impact of

B

1
,

|

|

in KBM driven scenarios.
The effects of sequential annealing in NO and wet-O2 on interfacial properties and reliability of 4H-SiC (0001) MOS devices
Authors: Lu Wenhao , Ge Niannian , Wan Caiping , Xu Hengyu , Jin Zhi , Ye Tianchun , Zhou Jingtao
Published: December 2024

Post-oxidation annealing (POA) is widely employed in academic research as well as in mass production to improve the properties of SiC MOS devices. We investigated the effect of sequential annealing in NO and wet-O2 on interfacial properties and reliability of 4H-SiC MOS capacitors. Compared with the SiC MOS capacitors with normal NO annealing, the sample with NO and wet annealing shows almost identical interface state density, near-interface trap density and the F-N effective barrier height. Regarding the breakdown characteristics, the charge-to-breakdown (QBD) of sample NO/wet is increased by two times than sample NO at cumulative failure probability F = 63.2 %. Moreover, XPS analysis results confirm that sequential annealing can reduce the interface states and improve the oxide reliability by eliminating Si-related SiOxCy defects and carbon-related defects. The subsequent wet annealing can not only annihilate oxygen vacancies which are generated by additional oxidation after NO POA, but also suppress the deterioration of bulk SiO2 quality to further improve the gate oxide reliability of SiC MOS structures. These results will be useful for the improved control of the interface state passivation technologies and the further optimization of the properties of the SiO2/4H-SiC interface.
Deep knowledge transfer powered ultrasonic guided wave damage monitoring under incomplete database scenarios: theories, applications and challenges
Authors: Hong Xiaobin , Cai Yifan , Chen Zhuyun , Huang Ruyi , Zhang Bin
Published: December 2024

Ultrasonic guided waves (UGWs) can travel long distances within the detected structures, which is of great significance for monitoring large complex engineering systems. However, the multimodal and dispersive properties of the specific research object making this promising whole structure monitoring difficult to interpret the signal mathematically and physically. With the development and maturity of deep learning and big data mining technologies, many scholars have noticed artificial intelligence algorithms such as deep learning can provide a new tool in UGWs signal processing, avoiding the mechanism analysis difficulties in the application of UGWs. But the integrity of structural state data sets has become a new pain point in engineering applications under this new approach, and how to apply the knowledge obtained from the existing data set to different but related fields through knowledge transfer in such cases begin to attract the attention of scholars and engineers. Although several systematic and valuable review articles on data-driven UGWs monitoring methods have been published, they only summarized relevant studies from the perspective of data-driven algorithms, ignoring the knowledge transfer process in practical application scenarios, and the intelligent UGWs monitoring methods based on knowledge transfer of incomplete sets are still lacking a comprehensive review. This paper focuses on the UGWs transfer monitoring technology when the training sample is missing, explores the feature correlation between samples in different domains, improves the transfer ability of the structural monitoring model under different conditions, and analyzes the UGWs intelligent monitoring methods for structural state under different sample missing conditions from three aspects: semi-supervised monitoring, multi-task transfer and cross-structure transfer. It is also expected to provide a new method and approach to solve the condition monitoring problems in other complex scenarios.
Large upper critical fields and strong coupling superconductivity in the medium-entropy alloy (Ti1/3Hf1/3Ta1/3)1−xNbx
Authors: Li Longfu , Tian Hongyan , Hu Xunwu , Zeng Lingyong , Li Kuan , Yu Peifeng , Wang Kangwang , Chen Rui , Xiang Zaichen , Yao Dao-Xin , Luo Huixia
Published: December 2024

Since the discovery of high-entropy superconductors in 2014, superconductivity has remained a focal point of interest in medium- and high-entropy alloys (MEAs-HEAs). Here, we report a series of (Ti1/3Hf1/3Ta1/3)1−x
Nb
x
(0 ⩽ x⩽ 0.9) MEA superconductors crystallized in the body-centered cubic structure, whose superconductivity was characterized by resistivity, magnetization, and specific heat measurements. The study found that the (Ti1/3Hf1/3Ta1/3)1−x
Nb
x
MEAs exhibit bulk superconductivity. With the doping of Nb, the superconducting transition temperature (T
c) increases from 5.31 to 9.11 K, and the normalized C
el jumps at T
c, ΔC
el/γT
c, and the logarithmically averaged characteristic phonon frequency ω
log exhibit dome-shaped curves. Results from specific heat measurements indicate that the superconductivity is of a strongly coupled s-wave type observed at 0 ⩽ x⩽ 0.75. Furthermore, at low Nb content (0 ⩽ x ⩽ 0.125), the upper critical field of the samples is larger than the Pauli paramagnetic limit. The strongly coupling behavior and large upper critical field in s-wave type (Ti1/3Hf1/3Ta1/3)1−x
Nb
x
MEA superconductors are unusual, as they typically occur in other unconventional superconductors. Thus, (Ti1/3Hf1/3Ta1/3)1−x
Nb
x
may have significant potential in the research and understanding of physical mechanisms.
Monitoring fatigue failure in REBCO coated conductors at cryogenic temperatures using advanced optical fiber sensors
Authors: Zhang Pengnian , Wang Xingzhe , Guan Mingzhi , Chen Sikan , Pan Yuanzhou , Xin Canjie , Wu Wei , Zhu Jiamin , Lin Xiaohui
Published: December 2024

Fatigue failure from cyclic loading, such as thermal cycles and electromagnetic forces, poses a significant challenge for rare-earth barium copper oxide (REBCO) coated conductor tape. Addressing this issue requires effective real-time evaluation techniques to enhance our understanding of fatigue properties and predict potential failures. A new method has been developed to detect and locate fatigue damage by reconstructing time-series macro-strain data using Rayleigh scattering-based optical frequency-domain reflectometry distributed optical fiber sensors (DOFSs). These newly developed copper-coated sensors are installed on the surface of REBCO CC tape, achieving perfect fit and consistency with the deformation of the tape. The strain measurements obtained from soldered-DOFS and bonded-DOFS, which used epoxy resin at liquid nitrogen temperature, were compared. A series of cyclic tests at this temperature differentiated mechanical and thermal fatigue using soldered-DOFS. An empirical model for fatigue damage in REBCO, based on accumulated maximum strain data, was established, explaining how mechanical parameters and temperature changes affect fatigue properties. Experimental results show that soldered-DOFS outperforms bonded-DOFS under cyclic loading at liquid nitrogen temperature. This provides a reliable way to measure and distinguish between mechanical and thermal fatigue, and aids in detecting and locating damage, as well assessing the remaining life of REBCO CC tapes.
Dissipation-accuracy tradeoffs in autonomous control of smart active matter
Authors: Cocconi Luca , Mahault Benoît , Piro Lorenzo
Published: December 2024

The study of motility control by smart agents offers a promising platform for systematically exploring the fundamental physical constraints underlying the functioning of bio-inspired micro-machines operating far from equilibrium. Here, we address the question of the energy expenditure required for a self-steering active agent to localise itself within a specific region of space or follow a pre-defined trajectory under the influence of fluctuations and external flows. Building on a stochastic thermodynamic formulation of the problem, we derive a generic relationship between dissipation and localisation accuracy, which reveals a fundamental dissipation-accuracy tradeoff constraining the agent’s performance. In addition, we illustrate how our framework enables the derivation of optimal steering policies that achieve localisation at minimum energy expenditure.
Computational insights into the impact of co-doping and induced pressure on magnetic switching properties of multiferroic for data transfer
Authors: Tariq Muhammad , Shaari Amiruddin , Tufail Kashif , Ahmed Rashid , Yamusa Shehu Aminu
Published: December 2024

Bismuth ferrite BiFeO3 (BFO) stands out as one of the most extensively researched multiferroic materials due to its magnetoelectric switching behavior. First-principles analysis within generalized gradient approximation plus Hubbard U (GGA+U) was employed to investigate the effects of lanthanum (La) doping at the A-site and nickel (Ni) doping at the B-site, as mono- and co-dopants, on spin-polarized electronic, structural, and magnetic properties for magnetic switching. The lattice constant and volume of BFO decrease linearly with increasing pressure. BFO in its cubic phase with space group Pm-3m typically exhibits metallic behaviour. However, the semiconducting nature of BFO in cubic phase has been observed, accompanied by enhanced magnetism (8.73 × 104 A m−1), strong magnetoelectric coupling (1.82 × 10−7 m−1sec) and a colossal value of magnetic force (1.82 T) at 60 GPa pressure. In Ni-substituted BFO structure, a large magnetization of 7.83 × 104 A m−1 and a linear magnetoelectric coupling coefficient of 1.64 × 10−8 sec m−1 and a remarkably high magnetic force of 1.64 T were observed, which is suitable for data transfer applications.
Construction of silver-doped graphitic carbon nitride integrated zeolitic imidazolate framework as an ultra-sensitive probe for colorimetric detection application
Authors: Zairov Rustem R , Elgorban Abdallah M , Jameel Rafid Kamal , Albadr Rafid Jihad , Hatem Ali , Mansoor Aseel Salah , Radi Usama Kadem , Abd Nasr Saadoun , Alfagham Alanoud T , Janani Baadal Jushi
Published: December 2024

Malachite green, and phloxine B are highly effective antifungal, and antibacterial agents utilized primarily in aquaculture. It is classified within the Triarylmethane dye. Numerous studies have indicated that malachite green, and phloxine B are significantly toxic to both terrestrial and aquatic organisms. More critically, it poses substantial risks to human health and safety. As a result, several governments have prohibited its application in aquaculture and food production. There is a pressing need to develop a novel colorimetric probe for the detection of malachite green, and phloxine B. In response, a composite material was synthesized, combining Zeolitic Imidazolate Framework (ZIF-8) with silver-doped graphitic carbon nitride (Ag-g-C3N4), to serve as a colorimetric probe for the sensitive and selective identification of malachite green, and phloxine B. The Ag-g-C3N4/ZIF-8 composite demonstrated exceptional colorimetric sensing capabilities, attributed to the synergistic interactions between ZIF-8 and Ag-g-C3N4, achieving a detection limit as low as 1.073 nM, and 1.214 nM, for malachite green, and phloxine B, respectively. This composite represents a significant advancement in environmental sensing technology, providing a versatile and effective approach for detecting and addressing contamination in water resources.
Oscillatory nonlocal solitons confined by a rectangular boundary
Authors: Wang Jing , Zhang Peishan , Hu Wei
Published: December 2024

We investigate solitons in nonlinear media with oscillatory nonlocal response, which are confined within a rectangular boundary. We find that the profile of soliton exhibits a nearly Gaussian shape regardless of the boundary value, and is located in the center of the rectangle. The profile of nonlinear refractive index, which exhibits a bell-shaped or oscillatory pattern, is strongly related to the value of the boundary and the degree of nonlocality. The normalized amplitude can also influence the profile of nonlinear refractive index. The stability of the soliton depends on its location within the domain defined by the function relationship curve of the propagation constant and the boundary, the degree of nonlocality, or the normalized amplitude. We further demonstrate the robustness of soliton propagation by the application of initial transverse velocity on solitons and the incident of solitons deviating from the center of the system, resulting in a snake-shaped propagation and chaoticon-shaped pattern.
Analytical investigation of a Dirac particle dynamics in a hyperbolic magnetic field with position-dependent mass: exact solutions and ladder operators
Authors: Kisoglu H F , Ala Volkan
Published: December 2024

This study analytically scrutinizes a system consisting of a Dirac particle in a certain external magnetic field. In the case where the external magnetic field depends on the position in a hyperbolic form and the particle has a hyperbolic effective mass (position-dependent mass), the two-component Dirac equation is used to algebraically obtain the polynomial eigenfunctions and exact energy-eigenvalues of the system. By means of these exact solutions, the ladder operators of the system are obtained. Thus, those who handle the DKP equation for the same system may benefit from these operators.
Numerical study of the variable-order time-fractional KP-BBM equation in 2D using RBFs
Authors: Sakariya Harshad , Kumar Sushil
Published: December 2024

Water waves are a complex phenomenon often examined due to their unpredictable nature and potential hazards in oceans and coastal areas. This study investigates the non-linear variable-order time-fractional Kadomtsev-Petviashvili-Benjamin-Bona-Mahony (KP-BBM) equation across three different two-dimensional space domains. We employ a finite difference method for temporal variables and radial basis functions (RBFs) for spatial variables to solve the model. The computational model is validated by comparing it with exact solutions for classical integer-order models, ensuring that it aligns with the classical integer-order model as the time-fractional order approaches one. The study also aims to evaluate the impact of various parameters in the equation and the dispersion effects of different time-fractional variable orders compared to classical waves.
Investigating rotating black holes in bumblebee gravity: insights from EHT observations
Authors: Islam Shafqat Ul , Ghosh Sushant G. , Maharaj Sunil D.
Published: December 2024

The EHT observation revealed event horizon-scale images of the supermassive black holes Sgr A* and M87* and these results are consistent with the shadow of a Kerr black hole as predicted by general relativity. However, Kerr-like rotating black holes in modified gravity theories can not ruled out, as they provide a crucial testing ground for these theories through EHT observations. It motivates us to investigate the bumblebee theory, a vector-tensor extension of the Einstein-Maxwell theory that permits spontaneous symmetry breaking, resulting in the field acquiring a vacuum expectation value and introducing Lorentz violation. We present rotating black holes within this bumblebee gravity model, which includes an additional parameter ℓ alongside the mass M and spin parameter a — namely RBHBG. Unlike the Kerr black hole, an extremal RBHBG, for ℓ < 0, refers to a black hole with angular momentum a > M. We derive an analytical formula necessary for the shadow of our rotating black holes, then visualize them with varying parameters a and ℓ, and also estimate the black hole parameters using shadow observables viz. shadow radius Rs
, distortion δs
, shadow area A and oblateness D using two well-known techniques. We find that ℓ incrementally increases the shadow size and causes more significant deformation while decreasing the event horizon area. Remarkably, an increase in ℓ enlarges the shadow radius irrespective of spin or inclination angle θ
0.
Coherence revival under the Unruh effect and its metrological advantage
Authors: Wang Jiafan , Zhang Jing-Jun , Feng Jun
Published: December 2024

In this paper, we investigate the quantum coherence extraction between two accelerating Unruh–DeWitt detectors, coupling to a scalar field in (3 + 1)-dimensional Minkowski spacetime. We find that quantum coherence as a nonclassical correlation can be generated through the Markovian evolution of the detector system, just like quantum entanglement. However, with growing Unruh temperature, in contrast to monotonously degrading entanglement, we find that quantum coherence exhibits a striking revival phenomenon. For certain detectors’ initial state choices, the coherence measure will reduce to zero at first and then grow to an asymptotic value. We verify such coherence revival by inspecting its metrological advantage on the quantum Fisher information (QFI) enhancement. Since the maximal QFI bounds the accuracy of quantum parameter estimation, we conclude that the extracted coherence can be utilized as a physical resource in quantum metrology.
Gyrokinetic simulations of the effects of magnetic islands on microturbulence in KSTAR
Authors: Wei Xishuo , Nicolau Javier H , Choi Gyungjin , Lin Zhihong , Yang Seong-Moo , Kim SangKyeun , Lee WooChang , Zhao Chen , Cote Tyler , Park JongKyu , Orlov Dmitri
Published: December 2024

Gyrokinetic simulations are utilized to study effects of magnetic islands (MIs) on the ion temperature gradient (ITG) turbulence in the KSTAR tokamak with resonant magnetic perturbations. Simulations show that the transport is controlled by the nonlinear interactions between the ITG turbulence and self-generated vortex flows and zonal flows, leading to an anisotropic structure of fluctuation and transport on the poloidal plane and in the toroidal direction. MIs greatly enhance turbulent transport of both particle and heat. The turbulent transport exhibits variations in the toroidal direction, with transport through the resonant layer near the island X-point being enhanced when the X-point is located at the outer mid-plane. A quantitative agreement is shown between simulations and KSTAR experiments in terms of time frequency and perpendicular wavevector spectrum.
Design and optimization analysis of key parameters for a compact ion source for BNCT
Authors: Yang Yang , Wang Guan , Zhou Wenming , Su Xingkang , Gu Long , Yun Di
Published: December 2024

The 2.45 GHz Electron Cyclotron Resonance Ion Source
(ECRIS) is widely recognized as an effective device for producing
high-intensity H+, H2
+, and H3
+ beams. In
medical cyclotron applications, ion sources are required to be
compact and highly adjustable. A compact design not only reduces the
equipment size, facilitating integration and installation, but also
enhances system stability and reliability. High precision in
adjustment ensures the quality and stability of the ion beam,
meeting the stringent requirements of medical treatments. Therefore,
designing a high-performance compact ECR ion source is crucial for
improving the performance and efficiency of medical cyclotrons. In
this study, we designed an ECR ion source with a discharge chamber
radius of only 25 mm and investigated its plasma formation using a
three-dimensional model. We explored the effects of different
microwave window positions on the extracted beam current,
calculated, and determined the optimal position. Additionally, we
studied the variations in the fractions of H+, H2
+, and H3
+ ions in the chamber with respect to pressure and
microwave power, and discussed the plasma processes within the ECR
ion source chamber based on these findings.
Optimization of LYSO crystals and SiPM parameters for the CMS MIP timing detector
Authors: Addesa F. , Anderson T. , Barria P. , Basile C. , Benaglia A. , Bertoni R. , Bethani A. , Bianco R. , Bornheim A. , Boldrini G. , Boletti A. , Bulla A. , Campana M. , Cardwell B. , Carniti P. , Cetorelli F. , De Guio F. , De Leo K. , De Riggi F. , Dervan J. , Fernandez E. , Gaile A. , Gallinaro M. , Ghezzi A. , Gotti C. , Goldouzian R. , Guglielmi V. , Heering A. , Hu Z. , Jose M. , Karneyeu A. , Krishna A. , Kronheim B. , Kuo C. , La Torre A. , Li A. , Lombardi F. , Lucchini M.T. , Malberti M. , Mao Y. , Marzocchi B. , Meridiani P. , Musienko Y. , Neu C. , Organtini G. , Orimoto T. , Palmer C. , Paganoni M. , Palluotto S. , Paramatti R. , Pessina G. , Perelman R.T. , Quaranta C. , Redaelli N. , Redaelli S. , Reales Gutiérrez G. , Ronchi S. , Santanastasio F. , Schmidt I. , Silva J.C. , Sorrentino G. , Sun X. , Tabarelli de Fatis T. , Tosi M. , Ujvari B. , Varela J. , Wang J. , Wayne M. , White S. , Zhang L. , Zhang M.
Published: December 2024

For the High-Luminosity (HL-LHC) phase, the upgrade of the Compact Muon Solenoid (CMS) experiment at CERN will include a novel MIP Timing Detector (MTD).
The central part of MTD, the barrel timing layer (BTL), is designed to provide a measurement of the time of arrival of charged particles with a precision of 30 ps at the beginning of HL-LHC, progressively degrading to 60 ps while operating in an extremely harsh radiation environment for over a decade.

In this paper we present a comparative analysis of the time resolution of BTL module prototypes made of LYSO:Ce crystal bars read out by silicon photo-multipliers (SiPMs).
The timing performance measured in beam test campaigns is presented for prototypes with different construction and operation parameters, such as different SiPM cell sizes (15, 20, 25 and 30 μm), SiPM manufacturers and crystal bar thicknesses. The evolution of time resolution as a function of the irradiation level has been studied using non-irradiated SiPMs as well as SiPMs exposed up to 2 × 1014 neq/cm2 fluence.
The key parameters defining the module time resolution such as SiPM characteristics (gain, photon detection efficiency, radiation induced dark count rate) and crystal properties (light output and dimensions) are discussed.
These results have informed the final choice of the MTD barrel sensor configuration and offer a unique starting point for the design of future large-area scintillator-based timing detectors in either low or high radiation environments.
Optimization of the magnetic field in the SK1000 central region model magnet
Authors: Wang J. , Yao Q.G. , Dou G.L. , Lyu M.B. , Zhao L.X. , Zhang X. , Wei Z. , Sun L.T. , Zhao H.W.
Published: December 2024

This study presents a design scheme for a central region
model magnet, based on a high-intensity compact cyclotron. The
objective is to ensure the long-term stable production of
therapeutic radionuclides such as 211At and
225Ac, while maintaining reasonable construction
and operational costs. In-depth research into the design principles
and core parameters of the CRM (Central Region Model) cyclotron
magnet system, guided by the concept of isochronous magnetic field
design, enabled the optimization of the magnet's dimensions and
magnetic field distribution. The optimization results show that the
magnet system meets the acceleration and focusing requirements of
the particle beam, effectively prevents particles from entering
dangerous resonance regions, and aligns with the theoretical
requirements of isochronous magnetic fields. This method keeps the
error between the calculated magnetic field and the theoretical
design field within 5 Gauss, meeting the expected physical design
standards.
Beam dynamics studies on a specific radio-frequency quadrupole injector for superconducting linacs
Authors: Zhou Bowen
Published: December 2024

Radio-frequency quadrupole (RFQ) linear accelerators are
widely used at the front end of large-scale hadron accelerator
facilities owing to their extraordinary performance of
progressive bunching, high-efficiency acceleration and low
emittance growth. Meanwhile, it is worth noting that RFQ linacs gradually
become the only normal conducting accelerators in modern
continuous-wave high-power superconducting hadron linacs. As a result, high-quality beams at the exit of RFQ linacs with respect to
more strict beam dynamics requirements are demanded, where minimizing the
emittance growth is one of the most critical design
targets. Not only a small rms emittance is required for an easy rms
match to the following superconducting cavities but also a small total
emittance is needed to reduce the beam loss in the superconducting
cavities. In this paper, the design parameters of some typical RFQ injectors for
superconducting linacs worldwide were compared, and the beam
dynamics design of a 162.5 MHz, 2.1 MeV, continuous-wave
RFQ linac was performed. Guided by the design approach
called MEGLET (Minimizing Emittance Growth via Low Emittance
Transfer), the beam dynamics design of the example RFQ injector was
completed with high transmission efficiency, low emittance growth,
and large error tolerance. The design result could be a reference for similar RFQ linacs, and the beam dynamics design approach is useful and applicable for other linacs intended to improve the figures of merit.
Co-producing water service delivery: a scoping review and typology of informal water vending in Sub-Saharan Africa
Authors: Gilson Gina Grace , Garrick Dustin
Published: December 2024

Informal water providers play a critical role in addressing water supply gaps, especially where rapid urbanisation outpaces the expansion of water networks. They are widespread in Sub-Saharan Africa (SSA), where over 80% of workers are informally employed, and approximately 70% of the population lack access to improved drinking water. Amidst lags in progress towards SDG 6.1 of universal and equitable access to safe and affordable drinking water, there has been growing interest in the role of these vendors and how co-production between formal and informal water supply actors might improve outcomes for different types of consumers. However, we know little about the coordination mechanisms in place and how they operate in practice. We conduct a scoping review of empirical research over the last 20 years to develop insights regarding the different types of co-production that may increase water access. We reviewed published sources to develop a better understanding of the water sources and delivery methods of informal water vendors, and the mechanisms of coordination between formal and informal sectors. To supplement the findings, we develop illustrative examples of the evolution and dynamics of different coordination mechanisms. The article shows how formal (often public utilities) and informal (often private and small scale) water providers are co-producing service delivery in SSA, with insights regarding the different coordination mechanisms that might help or hinder efforts to increase water access. We find that enforcement capacity is crucial for effective coordination, which creates a dilemma: many regions most dependent on informal water providers are least capable of monitoring, let alone enforcing rules. Consumers can benefit from coordination mechanisms that require less effort, such as quality testing, technical assistance, and preferential rates for bulk resale. By specifying how the formal and informal sectors are linked, further studies on co-produced water systems can contribute to evidence regarding what coordinated service delivery options might offer short- and medium-term solutions.
Sensitivity of Arctic marine heatwaves to half-a-degree increase in global warming: 10-fold frequency increase and 15-fold extreme intensity likelihood
Authors: León-FonFay Dalena , Barkhordarian Armineh , Feser Frauke , Baehr Johanna
Published: December 2024

We utilize the 50-member MPI-ESM-LR Earth System model to investigate the projected changes in Arctic marine heatwaves’ (MHWs) characteristics caused by an additional 0.5 ∘C increase in global warming, from 1.5 ∘C to 2 ∘C, with respect to pre-industrial levels. Our results indicate that this 0.5 ∘C increase in global warming triggers an intensified reaction in both the Arctic’s mean sea surface temperature (SST) and variability. In a 2 ∘C warmer world, one out of every four summer months would be warmer than the current climate. We detect a nonlinear increase of MHW intensity in a 2 ∘C world, which is characterized by a break in slope occurring around the year 2042 ± 2 (across 50 ensemble members of the SSP5-8.5 scenario). At the estimated post-break dates, the intensity rate roughly doubles, leading to MHWs in a 2 ∘C world with average cumulative heat intensity 100 ∘C*days higher than in a 1.5 ∘C world. Further results reveal that an extremely rare MHW with an intensity of 3.19 ∘C, classified as a 1-in-100-year event in a 1.5 ∘C world, is expected to transform into a 1-in-7-year event in a 2 ∘C world. This transition signifies a ∼15-fold increase in the likelihood of such events occurring due to a 0.5 ∘C increase in global warming. Likewise, a rare occurrence of years featuring 125 MHW days in a 1.5 ∘C world is projected to become a 1-in-10-year event in a 2 ∘C world, resulting in a 10-fold increase in occurrence probability. The main contributor to these changes is predominantly the rise in mean SST, with enhanced SST variability playing a minor role. These findings highlight that a 2 ∘C world could lead to a substantial escalation of the frequency and intensity of MHWs in the Arctic compared to a 1.5 ∘C world, transforming what are currently rare extreme events into more common events, with significant implications for global climate dynamics and the well-being of Arctic ecosystems and communities.
Current fluctuations in finite-sized one-dimensional non-interacting passive and active systems
Authors: Biswas Arup , Jose Stephy , Pal Arnab , Ramola Kabir
Published: December 2024

We investigate the problem of effusion of particles initially confined in a finite one-dimensional box of size L. We study both passive as well active scenarios, involving non-interacting diffusive particles and run-and-tumble particles (RTPs), respectively. We derive analytic results for the fluctuations in the number of particles exiting the boundaries of the finite confining box. The statistical properties of this quantity crucially depend on how the system is prepared initially. Two common types of averages employed to understand the impact of initial conditions in stochastic systems are annealed and quenched averages. It is well known that for an infinitely extended system, these different initial conditions produce quantitatively different fluctuations, even in the infinite time limit. We demonstrate explicitly that in finite systems, annealed and quenched fluctuations become equal beyond a system-size dependent timescale,

t
∼

L
2

. For diffusing particles, the fluctuations exhibit a

t

growth at short times and decay as

1

/

t

for time scales,

t
≫

L
2

/

D

, where D is the diffusion constant. Meanwhile, for RTPs, the fluctuations grow linearly at short times and then decay as

1

/

t

for time scales,

t
≫

L
2

/

D

eff

, where D
eff represents the effective diffusive constant for RTPs. To study the effect of confinement in detail, we also analyze two different setups (i) with one reflecting boundary and (ii) with both boundaries open.
Scanning probe spectroscopy of sulfur vacancies and MoS2 monolayers in side-contacted van der Waals heterostructures
Authors: Nisi K , Thomas J C , Levashov S , Mitterreiter E , Taniguchi T , Watanabe K , Aloni S , Kuykendall T R , Eichhorn J , Holleitner A W , Weber-Bargioni A , Kastl C
Published: December 2024

We investigate the interplay between vertical tunneling and lateral transport phenomena in electrically contacted van der Waals heterostructures made from monolayer MoS2, hBN, and graphene. We compare data taken by low-temperature scanning tunneling spectroscopy to results from room-temperature conductive atomic force spectroscopy on monolayer MoS2 with sulfur vacancies and with varying hBN layers. We show that for thick hBN barrier layers, where tunneling currents into the conductive substrate are suppressed, a side-contact still enables addressing the defect states in the scanning tunneling microscopy via the lateral current flow. Few-layer hBN realizes an intermediate regime in which the competition between vertical tunneling and lateral transport needs to be considered. The latter is relevant for device structures with both a thin tunneling barrier and a side-contact to the semiconducting layers.
Research status of reversed austenite in martensite: review
Authors: Shao Juhao , Wang Shiqing , Li Fangpo
Published: December 2024

This paper studies the role of reversed austenite in martensitic stainless steels, summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation. It also summarizes common heat treatment methods for obtaining reversed austenite in martensitic stainless steels and compares the advantages and disadvantages of various approaches. For example, layered quenching and tempering yield more reversed austenite compared to simple tempering, resulting in finer microstructures at room temperature. The paper analyzes how different reversed austenite contents affect the strength, ductility, and hardness of martensitic stainless steels, as well as the impact on pitting, intergranular, hydrogen, and stress corrosion. It finds that a higher amount of reversed austenite leads to a higher yield-to-tensile strength ratio, increased ductility, and lower hardness. While reversed austenite improves resistance to pitting, intergranular, and stress corrosion, its effect on hydrogen embrittlement remains debated. Additionally, the paper summarizes the formation principles of reversed austenite in martensitic stainless steels and reviews elements influencing its formation, aiming to identify optimal elements and heat treatment methods to increase reversed austenite content. This paper aims to make a summary of the research of experts and scholars in recent years, provide the knowledge foundation for the scholars who have just contacted, and give some reference for the future research direction.