bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and analysis of AGM explosion proof plug automatic assembly and inspection production line
Authors: Chen Jiaxiang , Chen Dongxing , Yang Fan
Published: December 2024

In order to achieve the automatic assembly and inspection of AGM battery explosion-proof plug bodies and acid-absorbed mats, this paper proposes a novel automatic assembly production line. The production line is designed for the assembly and functional testing of the explosion-proof plug bodies and acid-absorbed mats, aiming to enhance the automation level of assembly and testing processes for this product within the enterprise. Based on the requirements and operational conditions of the enterprise, the structure of the entire automatic assembly production line was designed using SolidWorks software. Furthermore, structural analysis and operational principles of crucial components were conducted. Static analysis of critical components of the grasping and translating mechanism within the device was performed using ANSYS software, validating the feasibility of its structural design.
Research on material protection for overhung pump cover: Suppressing vortex formation within the balance chamber
Authors: Chen Xiaoqing , Chen Shanmin , Yu Ruirong , Chen Fule , Cai Lanyong , Li Yujie , Lin Daxi
Published: December 2024

The column bottom pump is a crucial component of the atmospheric and vacuum device, and its stable operation is essential for the safe processing of crude oil. This paper analyzes the abnormal issues identified during the maintenance of a column bottom pump at a petrochemical plant, revealing a correlation between pump cover material damage and vortex formation in the balance chamber. A modification plan for the pump cover is proposed. The research results indicate that the installation of a baffle can effectively mitigate the vortex in the balance chamber, enhance the flow velocity through the balance holes, and subsequently alleviate the accumulation of solid particles and damage to the pump cover material. Feedback from engineering practices confirms that this improvement is both effective and reasonable.
Research on visual sensor occlusion test tools for autonomous vehicles
Authors: Geng Dongliang , Wang Meng , Zhang Zhiqiang , Shi Juan
Published: December 2024

In the research on the safety of intelligent driving vehicles, it is essential to test and verify the safety redundancy characteristics of the vehicle’s autonomous driving system. The safety redundancy capability of autonomous vehicles comes from the redundancy at the vehicle control level on the one hand, and the redundancy of environmental recognition sensors on the other. Among them, the camera sensors of the vehicle are generally distributed at multiple points inside and outside the vehicle to identify the external environment of the vehicle and the status of the driver in the vehicle. When some camera sensors on the outside of the vehicle are blocked while the vehicle is moving, the autonomous driving system should have a strategy to deal with it to avoid danger. For the verification of the above test scenarios, it is necessary to use the visual sensor occlusion tool to complete. In this paper, how the designed exterior vision sensor occlusion tool works normally under emergency braking conditions is studied.
Research on temperature control in additive manufacturing of thermosetting carbon fiber composites using DMC-IEPO-PID algorithm
Authors: Li Fang , Feng Xu , Wang Deyou
Published: December 2024

This study presents a novel temperature control strategy for Additive Manufacturing (AM) of thermosetting carbon fiber composites, integrating Dynamic Matrix Control (DMC), Improved Eagle Perching Optimization (IEPO), and a Proportional-Integral-Derivative (PID) controller, termed the DMC-IEPO-PID algorithm. This approach addresses traditional PID controller limitations like sluggish response, overshoot, and poor adaptability in complex manufacturing. By combining the simplicity of PID, adaptability of IEPO, and predictive accuracy of DMC, the algorithm improves temperature regulation in AM. Simulations and experiments at 250°C, 300°C, and 350°C showed superior performance in reducing fluctuations, stabilization time, and improving accuracy. The findings confirm the DMC-IEPO-PID’s effectiveness in handling nonlinearities and time-varying characteristics, optimizing AM processes for thermosetting composites.
Named entity identification method for manufacturing equipment faults based on improved Roberta
Authors: Li Nian , Wang Yunxia , Dong Ying , Qiu Shenghai
Published: December 2024

The recognition of manufacturing equipment fault named entities, as the foundation for constructing knowledge graphs in the field of fault diagnosis, has become an efficient identification method in fault diagnosis research. However, traditional methods for recognizing equipment fault named entities have shown insufficient performance in identifying professional vocabulary entities. This paper proposes a model for recognizing manufacturing equipment fault entities, which replaces the traditional Roberta model with the Roberta-wwm pre-trained model based on whole-word masking. The model improves its grasp of contextual information by integrating a bidirectional long short-term memory network and incorporating a multi-head attention mechanism to capture intricate interdependencies among fault entities in manufacturing equipment, and further optimizes the model’s performance. Experimental data from a large volume of fragmented fault texts generated during the operation and maintenance of certain resistance production equipment are used for validation. Through experiments, the F1 score for manufacturing equipment entity recognition is maximally increased by 2.58%, with evaluation metrics showing an F1 score of 98.76%, precision of 98.84%, and recall of 98.73%. This model provides an efficient and accurate solution for handling manufacturing equipment fault texts.
Numerical study of the characteristics of steam turbine shaft end combined seal
Authors: Meng Zhaojun , Wang Keyu , Meng Shuyu , Liu Da , Liu Shilong , Zhang Lei
Published: December 2024

Effective sealing is a critical factor in ensuring the operational efficiency of steam turbines. This paper introduces a novel Spiral-Labyrinth Combined Seal (SLCS), which integrates spiral teeth with traditional labyrinth teeth to form a composite seal. By incorporating the pumping effect of spiral teeth into the Labyrinth Seal (LS) design, the leakage is significantly reduced. This study investigates the pressure drop, sealing effectiveness, and the reduction in seal length for SLCS with one to six spiral teeth under identical operating conditions and then compares these three factors with traditional LS. The results demonstrate that on the steam side, the leakage of all SLCS is lower than that of traditional LS, and the sealing performance of SLCS with three spiral teeth is the best. The pressure drop of the SLCS with three spiral teeth is 37.81% higher than that of LS at the same length, the steam leakage is 27.14% lower than that of LS, and the axial length of the R-SLCS is 9.3% shorter than that of the LS. These results validate the feasibility of the new SLCS design, providing valuable insights for optimizing steam turbine shaft-end seals.
Internal short circuit fault diagnosis in Battery-Powered propulsion systems for ships using canonical variate analysis and curvilinear manhattan distance
Authors: Gu Yu , Ni Haishen , Li Yuwei
Published: December 2024

The battery-powered propulsion system for ships is a key component of new energy ship navigation. However, such systems will inevitably experience failures during operation, thereby resulting in a series of safety accidents. In particular, the event of an internal short circuit fault poses a significant threat to a battery-powered propulsion system for ships. In this paper, we propose a rapid detection and diagnosis method for ISC faults by combining canonical variable analysis and the curvilinear Manhattan distance. The method’s detectability and effectiveness are verified by simulating three ISC faults with different intensities.
Analysis and optimization of braking performance of 50-ton mining dump trucks
Authors: Zhang Kun , Mao Lixiang , Chang Ming , Meng Fanzhao , Liu Yuzhen
Published: December 2024

Braking performance is one of the main performances of an automobile and an important guarantee for safe driving. The quality of braking performance will directly affect traffic safety and personal safety. To solve the problem of low braking efficiency caused by the unreasonable distribution of braking force between the front and rear brakes of some mining vehicles in the current market, this paper uses the MATLAB simulation method to calculate the braking force distribution curve of a 50-ton mining automobile. By combining the adhesion coefficient and braking efficiency curve, the braking process of the automobile under certain working conditions of empty and full load is analyzed. By adjusting the braking force distribution coefficient, its braking performance is optimized. Further analysis and verification show that under full load conditions, the braking efficiency increases by 7.2%, the braking distance decreases by 3.8%, and the system performance optimization effect is significant.
Effect of minimum quantity lubrication on energy consumption in multi-axis milling of LY12 aluminum alloy
Authors: Zheng Tao , Zhang Tao , Zhao Nan , Dong Xiaochuan , Li Donghui , Gao Ming
Published: December 2024

The impact of milling parameters on energy consumption was investigated during blade machining by a four-axis milling machine under different conditions. LY12 aluminum alloy was used as a workpiece, and the single-factor experiments of different milling parameters (milling speed, feed rate, milling depth, and milling width) under minimum quantity lubrication (MQL) were carried out in the four-axis vertical machining center, as well as a comparison experiment with dry milling. The milling power was recorded by the three-phase electrical parameter tester, and the specific power was calculated. The overall milling power shows an upward trend with the increase of each milling parameter, while the specific power shows a downward trend under MQL and dry milling. MQL can effectively reduce milling energy consumption. The milling power and specific power decrease with the increase of oil-air flow rate and oil feeding frequency. When the oil supply frequency is 20 cy/min and the oil-air flow rate is 400 ml/min, the lubrication effect is relatively good.
A dual-loop dynamic drifting control framework for distributed drive electric vehicles
Authors: Yu Zhouhang , Wu Xiaodong , Zhao Wenbo , Su Jianye , Xu Min
Published: December 2024

As vehicular intelligence advances, drifting has been developed and applied to autonomous vehicles. This paper presents a real-time control framework to realize complex dynamic drifting maneuvers for DDEVs, which is called Dual-Loop Dynamic Drifting Control (DL-DDC). The framework is characterized by a dual-loop architecture. The inner loop is tasked with stabilizing the dynamic state quantities, and the outer loop is dedicated to tracking the kinematic state quantities. Validation is conducted in three different scenarios with Simulink/CarSim, and the results indicate that the proposed DL-DDC affords enhanced precision in dynamic stabilization and improved accuracy in kinematic tracking with a merely 0.6ms single-step solution time, which is pivotal for real-time hardware platform applications.
Research on synchronous control method of double-winding BLDC motor
Authors: Wang Yingchun , Zhang Nai , Zeng Ting , Wang Guoxin
Published: December 2024

The drilling system uses a spiral drilling tool to rotate and drive the core of deep lunar soil drilling. In response to the complex and variable environmental loads that affect the sampling effect of deep lunar soil drilling under limited resource conditions such as volume, weight, and power, a double-winding BLDC motor is used as the driving source for the rotation of the drill rod to achieve low-speed high torque starting and high-speed cutting and powder removal. The torque and speed mathematical models of the double-winding synchronous working and independent working of the BLDC motor are given, and the topology scheme of the double-winding synchronous working circuit of the BLDC motor is designed. A prototype is developed, and experimental research is carried out.
Marine variable air volume air conditioning system modeling and simulation
Authors: Liu Qian , Lu Jie , Huang Jing , Yi Xiaojun , Chen Minghao , Fang Zhen , Fan Zhuo
Published: December 2024

Air conditioning system is one of the significant energy consumption systems in Marine ship operations, and its economic operation is a vital measurement index. Variable Air Volume (VAV) air-conditioning system have gradually become mainstream air conditioning system on account of its remarkable energy saving. This study presents the fundamental concept and features, and active disturbance rejection control (ADRC) serves as the foundation for the proposed approach. A simulation study in MATLAB/Simulink has made a comparison with the PID controller, and the conclusion provides a reference value for the design and application of the VAV conditioning system.
Reinforcement learning control of lateral vibration of high-speed train carbody
Authors: Mou Ruqiang , Chen Chunjun
Published: December 2024

Increasing speed is one of the effective ways to raise high-speed train (HST) transportation capacity. However, increasing speed leads to greater vibration of HST with passive suspension, which can reduce the smoothness and safety of HST. Thus, a twin delayed deep deterministic policy gradient (TD3) control strategy was designed to reduce the lateral vibration of the HST carbody. The 3-degree-of-freedom (DOF) and 17-DOF models were utilized in designing the TD3 controller and simulation, respectively. In addition, the ballastless track spectrum of the Chinese high-speed railway was utilized to obtain the irregularities of the track. A reward function containing cost and penalty was designed to raise TD3 controller training efficiency. A linear quadratic optimal cost function and a step penalty function were designed, respectively. The control effect of the TD3 strategy was studied by simulation. The results indicate that TD3 can effectively reduce root-mean-square (RMS) and peak values for lateral acceleration at the front and rear ends of the HST carbody, and significantly improve the lateral smoothness of the HST carbody, which verifies validity of TD3 strategy.
Research on control strategy and system for preventing elevator car from colliding with the roof
Authors: Jia Haijun , Kang Dugang , Lv Xiao , Yin Cun , Zheng Jian
Published: December 2024

Car top-collision accidents caused by mechanical or electrical failures in traction-driven elevators occur occasionally, often resulting in serious casualties. To avoid such safety accidents, this paper designs a car anti-top-collision system based on hydraulic guide rail braking devices, proposes a system design scheme, and carries out mechanical calculations, hydraulic system design, control circuit, and control program design. Finally, the system control program is verified using Cade_SIMU software. This system plays an important role in preventing car top-running accidents.
Dynamic event-triggered adaptive positioning control of unmanned surface vehicles with system uncertainties
Authors: Liu Caiyun , Li Xingxin , Chen Xinghua , Liu Qian , Zheng Zhenming
Published: December 2024

To solve the problems of unmanned surface vehicles (USVs), such as limited network bandwidth and computing resources, a finite-time command filtering backstepping (FTCFB) robust adaptive dynamic positioning control method with dynamic event-triggered mechanisms (DETM) for unmanned surface vehicles (USVs) is proposed. It addresses thruster dynamics, system uncertainties, and unknown external disturbances, ensuring finite-time convergence while mitigating issues like communication congestion and actuator wear. Adaptive neural networks are utilized to estimate the system uncertainties, and a DETM-based FTCFB control law, validated with Lyapunov stability theory, guarantees finite-time convergence of tracking and parameter estimation errors. Numerical simulations confirm the method’s effectiveness.
Design and application of an automated video inspection system for the inner wall of pressure vessels in nuclear power plant reactors
Authors: Chen Yang , Wang Haijun , Xu Junlong , Du Yu
Published: December 2024

The pressure vessel of a nuclear power plant reactor is one of the key equipment in pressurized water reactor nuclear power plants, and its inner wall is an essential component of the pressure boundary in the primary loop. The inner wall of the reactor pressure vessel is subjected to long-term alternating stress and fluid erosion caused by the flow of the working fluid, which can easily form various surface defects such as pitting and unevenness. In order to timely detect and handle such defects while taking into account the maintenance period and personnel radiation risks, this paper designs an automated video inspection system for the inner wall of the pressure vessel of a nuclear power plant reactor with telescopic and pitching functions, which realizes the automatic video scanning of the inner wall of the pressure vessel and the precise positioning of defects.
Optimizing the configuration of grid-forming and grid-following control in doubly-fed wind farms considering machine-side dynamics
Authors: Chen Shuang , Chen Yan , Hong Jie , Tang Ge , Chen Yanming
Published: December 2024

With the growing integration of renewable energy, particularly wind power, into power systems, the effectiveness of wind farms in supporting grid stability is increasingly critical. Traditional grid-following (GFL) controls often fall short in weak grids with low short-circuit ratios (SCR), leading to stability issues. In contrast, grid-forming (GFM) controls, which simulate synchronous machine behavior, offer enhanced grid support and stability. This study investigates the optimization of control strategies for doubly-fed induction generator (DFIG) wind farms by comparing four configurations—grid-following DFIGs, grid-side GFM DFIGs, machine-side GFM DFIGs, and doubly grid-forming DFIGs. Through MATLAB/Simulink simulations, the study finds that doubly grid-forming DFIGs provide superior stability and grid support under low SCR conditions. These findings inform optimal configuration practices for wind farms in high-renewable-energy environments.
Noether-Wald and Komar charges in supergravity, fermions, and Killing supervectors in superspace
Authors: Bandos Igor , Meessen Patrick , Ortín Tomás
Published: December 2024

The supersymmetry properties of Killing vectors and spinors in supergravity theory can be clarified by relating them to Killing supervectors in the supergravity superspace. In the superspace approach it is manifest that supersymmetry ‘mixes’ a Killing vector with its fermionic spinor ‘superpartner’ and the Killing equations with the generalization of the Killing spinor equations. The latter reduces to the standard Killing spinor equation, albeit with a fermionic spinor, when the fermionic fields are set to zero. Using these supersymmetry transformations in the spacetime component approach, we construct a Noether-Wald charge of N = 1, D = 4 supergravity with fermionic contributions which is diff-, Lorentz- and supersymmetry-invariant (up to a total derivative). The Killing supervector formalism for the maximal D = 11 supergravity and some related issues are also discussed.
Kontsevich graphs act on Nambu–Poisson brackets, I. New identities for Jacobian determinants
Authors: Kiselev Arthemy V , Jagoe Brown Mollie S , Schipper Floor
Published: December 2024

Nambu-determinant brackets on ℝ
d
∋ x = (x
1, …, x

d
), {f, g}
d
(x) = ϱ(x) · det (∂(f, g, a
1, …, a

d−2) / ∂(x
1, …, x

d
)), with a

i
∈ C
∞ (ℝ
d
) and

ϱ
·

∂

x

∈

X

d

(

R

d

)

, are a class of degenerate (rank ⩽ 2) Poisson structures with (non)linear coefficients, e.g., polynomials of arbitrarily high degree. With ‘good’ cocycles in the graph complex, Kontsevich associated universal – for all Poisson bi-vectors P on affine

ℝ

aff

d

– elements

P

˙

=

Q

γ

(

[
P
]

)

∈

H

P

2

(

ℝ

aff

d

)

in the Lichnerowicz–Poisson second cohomology groups; we note that known graph cocycles γ preserve the Nambu–Poisson class {P (ϱ, [a]), and we express, directly from γ, the evolution

ϱ

˙

,

a

˙

that induces

P

˙

.

Over all d ⩾ 2 at once, there is no ‘universal’ mechanism for the bi-vector cocycles

Q

d

γ

to be trivial,

Q

d

γ

=
〚
P
,

X

→

d

γ

(

[
P
]

)

〛

, w.r.t. vector fields defined uniformly for all dimensions d by the same graph formula. While over ℝ2, the graph flows

P

˙

=

Q

2
D

γi

(
P

(
ϱ
)

)

for γ ∈ {γ3, γ5, γ7. …} are trivialised by vector fields

X

→

2
D

γ

i

=
(
d
x
∧
d
y

)

−
1

d

d
R

(

Ham

γ

i

⁡
(
P
)
)

of peculiar shape, we detect that in d ⩾ 3, the 1-vectors from 2D, now with P (ϱ,a
1,… ,a

d−2) inside, do not solve the problems

Q

d
⩾
3

γ
i

=
〚
P
,

X

→

d
⩾
3

γ
i

(
P

(
ϱ
,

[
a
]

)

)

〛

, yet they do yield a good Ansatz where we find solutions

X

→

d
=
3
,
4

γ
i

(
P

(
ϱ
,

[
a
]

)

)

. In the study of the step d → d + 1, by adapting the Kontsevich graph calculus to the Nambu–Poisson class of brackets, we discover more identities for the Jacobian determinants within P (ϱ, [a]), i.e. for multivector-valued GL(d)-invariants on

ℝ

aff

d

.
Pseudo-Conformal Field Theory
Authors: Ragiadakos C. N.
Published: December 2024

Starting from the observation that the 2-d Polyakov action is metric independent without being topological, while the 4-d Weyl-conformal action is not metric independent, I searched for a 4-d structure and field equation which would be metric independent. I found that the structure is the existence of a geodetic and shear-free Newman-Penrose (NP) null tetrad, which is a Frobenius integrable structure, called lorentzian Cauchy-Riemann (LCR) structure. The metric independent equation is a gauge field equation identified with the gluon field. Imposing the LCR-structure as the fundamental structure of nature (instead of the Einstein-metric) all the interactions (gravity, electroweak and gluonic) are derived. The three generations of the leptons are solitonic configurations with precise topological invariants. The quarks are confined sources of the gluonic field implied by the LCR-tetrad of the corresponding leptons. Quantum field theory emerges through the Bogoliubov causal approach and the standard model is derived through the Scharf procedure of the Kugo-Ojima BRS elimination technique of the unphysical modes of the spin-1 and spin-2 fields.
Real double flag variety for the symmetric pair (U(p, p), GLp(ℂ)) and Galois cohomology
Authors: Nishiyama Kyo , Tauchi Taito
Published: December 2024

Let G be the indefinite unitary group U(p, p), H ≃ GL

p
(ℂ) its symmetric subgroup, P

S
the Siegel parabolic subgroup of G, and B

H
a Borel subgroup of H. In this article, we give a classification of the orbit decomposition H
\(H/B

H

×
G/P

S
) of the real double flag variety by using the Galois cohomology in the case where p = 2.
Covariant Schwarz maps in M2(ℂ)
Authors: Chruściński Dariusz
Published: December 2024

We analyze a class of qubit maps displaying diagonal unitary and orthogonal symmetries. For unital maps we characterize all covariant maps satisfying an operator Schwarz inequality. In particular well known Pauli maps are completely characterized. Going beyond the unital case we consider recently proposed generalizations of Schwarz inequality and provide the corresponding necessary and sufficient conditions for the entire class of covariant maps.
Near-horizon aspects of black holes in quantum spacetime
Authors: Herceg Nikola , Jurić Tajron , Naveena Kumara A. , Samsarov Andjelo , Smolić Ivica
Published: December 2024

We give a short introduction to the formalism of noncommutative (twisted) differential geometry that is used to derive the equations of motion for the gravitational perturbation of the Schwarzschild black hole in quantized spacetime. Special attention is given to quantum spacetime arising from r
−
φ noncommutativity. Tortoise coordinate and near-horizon regions of the effective potentials are analyzed for both polar and axial modes. By carefully examining the associated Schrödinger-type equations, we provide the asymptotic solutions at the horizon and illustrate some differences between the polar and axial modes. These findings give further insight into the polar-axial isospectrality violation in the presence of the quantum structure of spacetime.
Super-stable points and cycles on double-tetrahedral chains
Authors: Amatuni G. , Burdik Č. , Poghosyan H. , Ananikyan L. , Ananikian N.
Published: December 2024

Quantum systems with antiferromagnetic spin-1 Ising and Ising-Heisenberg interactions with single-ion anisotropy on double-tetrahedral chains can exhibit unconventional classical and quantum states responsible for the anomalous behavior of magnetization curves at low temperatures. We find super-stable points and cycles for those chains when the temperature tends to zero.
Noncommutative spaces of geodesics with light-like κ-Poincaré covariance
Authors: Gutierrez-Sagredo Ivan , Ballesteros Angel , Herranz Francisco J.
Published: December 2024

The aim of this contribution is to highlight the relevance of the so-called light-like (or null-plane) κ-Poincaré quantum deformation in relation with the construction of noncommutative spaces in the context of quantum gravity phenomenology. The role of this deformation is enhanced when, in addition to the construction of quantum group covariant noncommutative spacetimes, noncommutative spaces of geodesics preserving the same quantum group symmetry are also considered.
Study of the calculation IR and modeling on nitrile rubber
Authors: Han Yu-Tian , Liu Chang-Kui
Published: December 2024

Nitrile rubber (NBR) is a common analysis object in the field of non-metallic failure analysis. Usually, the sample state greatly affects the quality of the spectrum when collecting its infrared spectrum (IR), leading to increased difficulty in interpretation. This paper took NBR as an example and carried on a discussion and comparative analysis for the calculated IR of NBR and its Modelling. As a result, a polymer modeling method for computational IR was proposed.
Cooperative game theory based coordinated scheduling of production and transportation of parallel machines with deterioration effects
Authors: Gong Hua , Zhang Yunna , Sun Wenjuan
Published: December 2024

Cooperative game theory is used to study the production and transportation scheduling problem of parallel machines with deterioration effects. Jobs with an initial scheduling order are processed on parallel machines and then transported to customers. Penalties are incurred for early or late completion if the jobs are not completed on the due dates. Considering that jobs can rearrange the scheduling order in the coalition through cooperation to bring about cost savings, the cooperative game model is constructed by considering the jobs as players and taking the maximum cost savings of the coalition as the characteristic function. It is proven that when jobs have the same normal processing time and deterioration rate, the cooperative game has a non-empty core, and a core allocation can be obtained from the β-rule allocation method. A Dual Replay Buffer Double DQN (DRB-DDQN) algorithm is designed to get the optimal schedule of the coalition. Experiments demonstrate the effectiveness of the DRB-DDQN and β-rule allocation method in solving the game scheduling problem.
Numerical simulation method for shock vibration based on finite element substructure
Authors: Liang Zhengang , Li Haoyu , Qi Hongli , Liu Ji’an , Guo Tengfei , Li Jianan , Zhao Han
Published: December 2024

For engineering problems such as shock vibration, finite element simulation is a very effective method, but for too large models, meshing them in finite element software generates a large number of grid cells, which is time-consuming to compute and limits the application of solid cells in the simulation of large models, so the use of the substructure method will effectively solve the problem. In this paper, we will first explore the influence of the mesh size on the simulation results to get the most suitable mesh. This paper will first investigate the effect of grid size on the simulation results to get the most appropriate grid size, and then use the substructure method to encrypt the grid of the part that needs to be studied and analyze it individually, and at the same time, carry out the validation experiments to compare the results with the substructure simulation results, to investigate the reasonableness of the substructure method in the propagation process of shock vibration.
Investigation of electron backscattering on silicon drift detectors for the sterile neutrino search with TRISTAN
Authors: Spreng D. , Urban K. , Carminati M. , Edzards F. , Fiorini C. , Lechner P. , Nava A. , Siegmann D. , Wiesinger C. , Mertens S.
Published: December 2024

Sterile neutrinos are hypothetical particles in the minimal
extension of the Standard Model of Particle Physics. They could be
viable dark matter candidates if they have a mass in the keV
range. The Karlsruhe tritium neutrino (KATRIN) experiment, extended
with a silicon drift detector focal plane array (TRISTAN), has the
potential to search for keV-scale sterile neutrinos by measuring the
kinematics of the tritium β-decay. The collaboration targets
a sensitivity of 10-6 on the mixing amplitude
sin2Θ. For this challenging target, a precise
understanding of the detector response is necessary. In this work,
we report on the characterization of electron backscattering from
the detector surface, which is one of the main effects that
influence the shape of the observed energy spectrum. Measurements
were performed with a tandem silicon drift detector system and a
custom-designed electron source. The measured detector response and
backscattering probability are in good agreement with dedicated
backscattering simulations using the Geant4 simulation
toolkit.
Development of 16MeV compact cyclotron RF system with solid-state amplifier and fully digital controller
Authors: Wang Z.Y. , Lei Y. , Fu H.R. , Cai X.W. , Liu W. , Li M. , Li H.P. , Lv Y.L. , Wang S.
Published: December 2024

State Power Investment Corporation (SPIC) developed a
16 MeV compact cyclotron for producing medical radioactive isotope
18F. The cyclotron radio frequency (RF) system's architecture
and hardware design as well as the control algorithms and software
design are discussed and tested in this paper. The RF system
includes a RF cavity, a 16 kW 38.44 MHz RF solid-state amplifier
(SSA), power transmission line systems and a fully digitalized
low-level RF (LLRF) unit. The RF cavity consists of two dees, a
coarse tuning plate, a fine-tuning plate, a RF feeding port, a RF
pickup port with a compact size and relatively low power
dissipation. The RF amplifier adopts an all-solid-state compact
design without any circulator as this cyclotron operates at a
relatively lower frequency, and cooperates with the digital LLRF
system to realize RF power feed-in at low frequency. By using LLRF
featuring functions of tuning control, amplitude control, and phase
control, the RF system achieved cavity frequency tuning, closed loop
amplitude and phase regulations of the cavity. Through a fully
digitalized low-level design, the system realized parameterized
configuration capabilities. By adopting non-IQ RF direct sampling,
the efficient noise suppression control was achieved. To reduce the
maintenance and operational complexity of the system, the system
adopted a novel hybrid frequency tuning algorithm that could enable
rapid tuning control of cyclotron cavity. Based on a brand-new
parameterized automated RF running process, the system realized
automatic RF power-up procedure. In beam commissioning, the measured
amplitude stability of the RF system was better than 0.1% and phase
stability was better than 0.3∘. The design and performance
test results of the RF system will be presented in this paper.
Reply to Comment on ‘Extreme weather events in early summer 2018 connected by a recurrent hemispheric wave-7 pattern’
Authors: Kornhuber Kai , Coumou Dim , Petri Stefan , Osprey Scott , Rahmstorf Stefan
Published: December 2024

Circumglobal teleconnections from wave-like patterns in the mid-latitude jets can lead to synchronized weather extremes in the mid-latitudes of Northern and Southern hemispheres. The simultaneous occurrence of record breaking and persistent northern hemisphere temperature anomalies in Summer 2018 were previously discussed in the context of a persistent zonally elongated wave-7 pattern that stretched over large parts of the northern hemisphere over an extended time and let to considerable societal impacts. Various diagnostics have been put forward to quantify and detect such wave patterns, many of which incorporate low-pass time filtering to separate signal from noise. In this response we argue that advancing our understanding of the large-scale circulation’s response to anthropogenic climate change and reducing associated uncertainties in future climate risk requires a diverse range of perspectives and diagnostics from both the climate and weather research communities.
Economic impacts of floods in China and adaptation strategies under climate change
Authors: Xue Ying , Xia Jun , Liu Yuan , Zou Lei
Published: December 2024

Climate change has intensified the frequency and severity of heavy rainfall and flooding in China, posing serious threats to economic and social stability. Over the past 40 years, the increasing trend of these events has led to significant economic losses, highlighting the urgent need to develop effective adaptation strategies in both research and policy. This study used the Adaptive Regional Input–Output model to comprehensively assess the economic impacts of the July 2021 Henan flood, with a main focus on indirect economic losses (IELs) that are often underestimated in traditional assessments. The findings revealed that the IELs were up to $37.9 billion, nearly twice the direct economic losses. Additionally, a sensitivity analysis showed that increasing production capacity and the timing required to achieve it were two key factors to reduce IELs. Based on these insights, this study proposes an adaptation strategy framework tailored to China’s current development context, where systemic governance, strategic investments, and technological innovation are accounted for. This framework offers practical strategies to reduce the impacts caused by floods, thereby providing valuable guidance for sustainable disaster risk reduction and long-term economic stability in China.
Investigating the December 2023 warm-to-cold weather whiplash in China using a novel flash-cold metric
Authors: Chen Huayu , Jiang Jilan , Liu Yimin
Published: December 2024

In mid-December 2023, China experienced an unprecedented cold wave that marked a critical stage in a negative temperature-related weather whiplash event (WWE), which was characterized by a rapid shift from extreme warmth to extreme cold. The traditional metric—temperature variance—is insufficient to reflect the temporal evolution of this WWE. Therefore, we introduce a novel metric termed ‘flash-cold’ to identify the sharp and significant decrease in surface air temperature. This new metric not only effectively captures recent WWEs trend in line with variance-based metric but also allows daily tracking of temperature shifts. Using the flash-cold metric, we delineate the evolution of the WWE case in China into four phases: first warm spell, first flash-cold, second warm spell, and second flash-cold (corresponding to the unprecedented cold wave). A recently proposed Lagrangian temperature budget analysis highlights the crucial role of high-latitude blocking circulation in both flash-cold phases through cold advection. The first flash-cold phase was triggered by backward cold air masses driven by upstream systems associated with Okhotsk blocking, while the second flash-cold phase developed when the trough downstream of Ural blocking moved eastward and rotated counterclockwise. In contrast, subtropical systems moderated the decreasing temperature during the first flash-cold through diabatic processes but had minimal impact on the second flash-cold, helping to explain why the second flash-cold was more intense. From a multiscale interaction perspective, the development of these blocking circulations was facilitated by a background of exceptionally weak meridional gradient of potential vorticity, the smallest recorded since 1979.
Using agent-based modelling to simulate the emission reduction potential of CCUS technologies in China under alternative policy packages
Authors: Dong Changgen , Sun Zhuoluo , Jiang Jingjing , Yang Yang
Published: December 2024

Carbon capture, utilisation, and storage (CCUS) technologies are essential for achieving the 1.5 °C target. Predicting the emission reduction potential of CCUS technology is particularly important for countries to pursue carbon neutrality. However, the existing literature assessing the potential lacks consideration of the structural changes in industrial product demand and the trade-offs companies face between CCUS and traditional emission reduction technologies. This study used agent-based modelling (ABM) to simulate the emission reduction potential of CCUS in China’s thermal power, steel, cement, and chemical industries from 2022 to 2060 under scenarios of different carbon prices, subsidies, and technology progress rates. The possible biases of the traditional prediction model were corrected incorporating the structural changes in industrial product demand and the marginal abatement cost curves of traditional emission reduction technologies for the four major industries into the ABM model. The simulation results indicate that under each of the ten possible scenarios, China’s CCUS technologies will reach 100% penetration in the four mentioned industries by 2060, with the emission reduction potential fluctuating between 2222 and 1568 Mt of CO2 (corresponding to 40% and 10% share of thermal power, respectively). The difference comes in the scaled-up threshold time point and the growth trend. Sensitivity analyses show that the carbon price affects changes in the emission reduction potential of CCUS technologies the most, while the impact of subsidies, rates of technological progress and oil prices were not significant. The stepped carbon price policy can effectively regulate and promote the expansion of CCUS emission reduction potential, which is worth considering for policymakers.
On the recurrence coefficients for the q-Laguerre weight and discrete Painlevé equations
Authors: Hu Jie , Dzhamay Anton , Chen Yang
Published: December 2024

We study the dependence of recurrence coefficients in the three-term recurrence relation for orthogonal polynomials with a certain deformation of the q-Laguerre weight on the degree parameter n. We show that this dependence is described by a discrete Painlevé equation on the family of

A

5

(
1
)

Sakai surfaces, but this equation is different from the standard examples of discrete Painlevé equations of this type and instead is a composition of two such. This case study is a good illustration of the effectiveness of a recently proposed geometric identification scheme for discrete Painlevé equations.
On the maximally symmetric vacua of generic Lovelock gravities*
Authors: Devecioğlu Deniz Olgu , Lindström Ulf G , Sarıoğlu Özgür
Published: December 2024

We survey elementary features of Lovelock gravity and its maximally symmetric vacuum solutions. The latter is solely determined by the real roots of a dimension-dependent polynomial. We also recover the static spherically symmetric (black hole) solutions of Lovelock gravity using Palais’ symmetric criticality principle. We show how to linearize the generic field equations of Lovelock models about a given maximally symmetric vacuum, which turns out to factorize into the product of yet another dimension-dependent polynomial and the linearized Einstein tensor about the relevant background. We also describe how to compute conserved charges using linearized field equations along with the relevant background Killing isometries. We further describe and discuss the special vacua which are defined by the simultaneous vanishing of the aforementioned polynomials.
Nuclear clock ticks closer
Authors: Dumé Isabelle
Published: December 2024

A new device might not only be the best time-keeper ever, but could also revolutionize fundamental physics, as Isabelle Dumé reports.
Founders of AI share physics Nobel
Authors: Johnston Hamish
Published: December 2024

John Hopfield and Geoffrey Hinton win the 2024 Nobel Prize for Physics for their work on machine learning and neural networks, as Hamish Johnston reports.
Creators of AI protein-structure prediction win chemistry Nobel
Authors: Johnston Hamish
Published: December 2024

The 2024 Nobel Prize for Chemistry has been awarded to David Baker, Demis Hassibis and John Jumper for their work on protein structure and design.
Physics gender gap entrenched by biased networks
Authors: Allen Michael
Published: December 2024

Biased collaboration and citation patterns are responsible for driving the gender gap in physics, finds a new study.
Fusion’s burning challenge
Authors: Matthews Guy
Published: December 2024

Guy Matthews says that the focus on public relations is masking the challenges of commercializing nuclear fusion.
Quantum brainwaves
Authors: Johnston Hamish , Skipper Katherine
Published: December 2024

Electrical impulses allow us to think, feel and form memories. Mapping these signals in the brain can be used to study cognitive development and disease. Margot Taylor and David Woolger talk to Hamish Johnston about using quantum-sensing technology to build a wearable system for imaging brain activity.
A study on forest fire risk assessment in jiangxi province based on machine learning and geostatistics
Authors: Lu Jinping , Li Mangen , Qin Yaozu , Chen Niannan , Wang Lili , Yang Wanzhen , Song Yuke , Zheng Yisu
Published: December 2024

Jiangxi Province, characterized by abundant forest resources and complex topography, is highly susceptible to forest fires. This study integrated multiple factors, including topography, climate, vegetation, and human activities, and employed machine learning models, specifically random forest (RF), support vector machine (SVM), and back-propagation neural network (BPNN), to predict forest fire occurrence in Jiangxi. Using Moderate Resolution Imaging Spectroradiometer L3 fire-point data from 2001–2020, we analyzed the spatiotemporal distribution of forest fires and applied the weight of evidence (WoE) method to evaluate the correlation between forest fires and environmental factors. WoE was employed to select negative samples, which were compared with those obtained using traditional random sampling methods. The optimal model was then utilized to generate seasonal spatial distribution maps of forest fire risk throughout Jiangxi Province. The results showed that over the past two decades, the frequency of forest fires generally decreased. RF demonstrated a significant advantage over SVM and BPNN in predicting forest fires. Vegetation coverage was the most influential factor. In addition, the models trained with WoE-selected negative samples exhibited enhanced accuracy, with area under the curve values increasing from 0.946 to 0.995 for RF, 0.8344 to 0.925 for SVM, and 0.832 to 0.850 for BPNN, compared to those trained with randomly sampled negative data. Finally, forest fires were most frequent during winter, particularly in Ganzhou, Fuzhou, and Ji'an. High-risk fire zones were more dispersed in spring, whereas autumn fires were primarily concentrated in Ganzhou, and fire activity was relatively low during summer. The seasonal forest fire risk maps generated in this study offer valuable insights for guiding forest fire management in the Jiangxi Province and similar regions, providing critical practical significance for informed decision-making.
Volcanic crop soil physicochemical characterization in semi-arid and temperate climates: two Mexican case studies
Authors: Luévano-Rivas O A , Chavez-Esquivel G , Ángeles-Beltrán D , Tavizón-Pozos J A
Published: December 2024

In this work, two crop soils were characterized: Querétaro (Bajío) and the State of Mexico (Edomex). Both states are part of the Sierra Madre Occidental, where temperate and subhumid climates are experienced. The surface soils are predominantly Leptosols in the Bajio and Andosols-Feozems in the Edomex. The dynamic mobility of water and fertilizers is associated with humic substances, mineralogical phases, metal dispersion, pore type, pore volume, and thermal behavior4

4

Behavior.

. Both agricultural soils exhibited high porosity and surfaces with co-dispersion of Al3+/Si4+ and Ti4+/Fe2+,3+ ions and mixed mineralogical phases such as montmorillonite, anorthite, quartz, magnetite, goethite, hematite, and kaolinite. On the one hand, the C/N values for the Bajio-crop and Edomex-crop soils showed values of 15 and 11, respectively. On the other hand, the Bajio-crop and Edomex-crop soils showed C/O values of 0.38 and 0.42, respectively, indicating the accumulation of organic carbon and the presence of various humic substances. Finally, the Bajio-crop soil presented a higher surface area, pore diameter, and pore volume than the Edomex-crop soil, which is associated with high adsorption and nutrient retention. On the contrary, the Edomex-crop soil presented greater thermal resistance than the Bajio-crop soil, which is associated with a better capacity for heat dissipation during irrigation processes or fertilizer application.
The Arrival of the Commercial Institutional Logic
Authors: Sytch Maxim
Published: December 2024

This chapter begins to uncover the motivations behind supplier-induced demand, locating them at the intersection of structure and agency, stemming from the shift in institutional logics in professional services. Institutional logics delineate the practices, norms, and cognitive perspectives ingrained within our work environments, shaping our perceptions of the work itself. Since the 1980s, professional services have undergone a profound transformation from an advisory institutional logic to a commercial one. These changes have permeated virtually every aspect of professional services, giving rise to sophisticated managerial structures and previously counter normative practices, such as external ownership, marketing one’s services, linking partnership status to partners’ ongoing productivity, recruiting rainmakers from rival firms, and embracing market-oriented principles in pursuit of growth and profitability. This shift in institutional logics has laid a powerful foundation for how professionals began to see their roles and work.
The Deuteragonist Self
Authors: Anooshahr Ali
Published: December 2024

This chapter shows how Jawhar negated the conditions of slavery by writing and constructing narrative “selves” for himself and the emperor. While the emperor was the protagonist, Jawhar was the secondary character or “deuterogonist” who accompanied the master, told his story, but also inserted himself in the chronicle of events as a capable and dutiful companion. Jawhar was able to do this in part thanks to his exposure of Shattari Sufism at the imperial court, to his exposure to Chishti hagiography in Delhi, and to his experience of writing reports to the emperor about his service as an administrator later in life.