bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural gas production process fault localization based on direct transfer entropy with adaptive lag
Authors: Chen Jiexue , Liang Bing , Nie Ke , Cui Yue , Wang Yuanyuan , Ren Hongji , Yin Aijun
Published: December 2024

Natural gas production equipment has complex structures, numerous monitoring parameters, and intricate correlation relationships, making it challenging to trace the source of faults for abnormal events. This paper proposes a fault localization method for natural gas production processes based on direct transfer entropy with adaptive lag (AL-DTE). Firstly, a variable set is screened based on the contribution plot. To enhance the adaptability to multiple operating conditions and reduce the reliance on experience, this paper integrates the adaptively to DTE and proposed AL-DTE. A causal analysis is then constructed and the causality graph is utilized to visualize the abnormal propagation path and identify the root cause of the fault. The proposed method can locate abnormal and faulty sub-equipment without relying on historical experience, enabling rapid localization of unknown faults. The effectiveness of the method is verified through simulation data and real faults of a triethylene glycol dehydration equipment.
Research status and prospects of intelligent logging lithology identification
Authors: Jin Huang , Yutong Ci , Xuan Liu
Published: December 2024

With the increasing of petroleum exploration and development, accurate lithology identification is of crucial. Machine learning (ML) plays a key role in logging lithology identification. By introducing traditional logging lithology identification methods, we review the application of ML in logging lithology identification from the perspectives of bibliometrics and ML classification in this paper. The applications of supervised learning, semi-supervised learning, unsupervised learning, ensemble learning, and deep learning algorithms in logging lithology identification are introduced in detail. Multiple ML algorithms have achieved remarkable results in different scenarios. For example, support vector machine, random forest, eXtreme gradient boosting, and convolutional neural network perform well in logging lithology identification and obtain relatively high identification accuracy. However, ML for logging lithology identification also faces challenges such as data quality, data imbalance, model generalization, and model interpretability. Future research should focus on algorithm optimization and innovation, improvements in data quality and quantity, deep multidisciplinary integration and practical application to enhance the accuracy and reliability of lithology identification. These findings provide strong support for oil and gas exploration and development.
An adaptive feature refinement network for pixel-level segmentation of surface defect
Authors: Zhang Yuzhong , Ge Wenhao , Liu Shiyang , Wang Jiazheng , Hu Haibing , Dong Jingtao , Zhang Tengda
Published: December 2024

In the field of industrial production, automatic surface defect segmentation plays a crucial role in improving product quality and production efficiency. However, due to the interference of complex backgrounds and uneven illumination, efficient and accurate segmentation of surface defect remains a significant challenge. To address these issues, this work proposes an adaptive feature refinement (AFR) U-shaped network (U-Net) for pixel-level segmentation of surface defect. The proposed framework draws inspiration from the classic U-Net architecture, and the pre-trained EfficientNet-B0 is selected as the encoder part to extract the multi-scale context information. Then, a novel AFR module, which further learns the global channel-wise dependencies and captures cross-channel local spatial patterns from multi-level features, is introduced to enhance the robustness of feature representation. Finally, these enhanced encoder features are up-sampled, and are further fed into the decoder part to obtain pixel-level defect segmentation results. To assess the validity and accuracy of the proposed model, this network is validated through extensive experiments on four different types of defect datasets. Experimental results show that the proposed model performs well on these datasets, with the maximum mean intersection over union (MIoU) of 91.63%. Meanwhile, the model is compared with some U-Net-based models and other state-of-the-art segmentation models, and it can also achieve competitive performance on MIoU scores. With the acceleration of the graphics processing unit, the proposed network can achieve a detection speed of 82 fps, which can meet the needs of real-time detection in the industrial fields.
Effect of Mn2+ ions and TOP molecules on the luminescence properties of oleic acid caped CsPbI3 nanocrystals
Authors: Huang Xiaozong , Li Wen , Kong Linghang , Lu Xiaoyan , Yang Chengzhi , Zou Bingsuo
Published: December 2024

Due to the easy transformation to the non-luminous yellow δ-CsPbI3 phase in air, α-CsPbI3 nanocrystalline materials with red light emission find limited applications. Lifting its structural stability is a challenge in its quantum dot (QD) lighting field. Here we studied the doping of Mn2+ ions (5.0%) and processing by a small amount (0.315 ml) of TOP molecules on the OA-capped CsPbI3 nanocrystals. It is found that after the successful introduction of Mn2+ into the CsPbI3 nanocrystal, the grain size reduces, which leads to a stronger quantum confinement effect than the undoped QDs, which leads to the blue shift of PL and absorption spectra. The incorporation of Mn2+ simultaneously reduced defects and lifted the luminescence efficiency and lifetimes of QDs, the cause for the above optical behavior is due to the formation of excitonic magnetic polaron (EMP) excitons near the bandedge. On the other hand, the treated TOP molecule on the OA-capped NCs did not significantly affect their room-temperature luminescence. However, it improved the low-temperature emission performances of QDs significantly. Moreover, the TOP-treated QDs fixed in the PMMA film can transform into rod-like shapes in acidic environments, giving strong stability for emission, especially for the Mn-doped CsPbI3 QDs. This work has been done to improve the stability and emission efficiency of related QDs through the EMP formation near band-edge and surface modification of CsPbI3 NCs, favoring their potential applications in display and low-temperature light-emitting devices.
Streamer propagation in CO2 and N2/CO2 mixtures at atmospheric pressure
Authors: Omori Kento , Ono Ryo , Komuro Atsushi
Published: December 2024

This study investigated streamer discharge in CO2 and N2CO2 mixtures. Experiments were conducted at atmospheric pressure and room temperature conditions by using a point-to-plane electrode configuration. A repetitive pulse discharge at 50 Hz was used to stabilise the discharge in CO2. Under these conditions, the discharge current and intensified charge-coupled device camera images were systematically analysed during streamer evolution in CO2. The results revealed that streamer propagation and electrical properties were considerably influenced by the N2 concentration in CO2. Analysis of the emission of secondary streamers indicated that the emission ratio of primary streamers and secondary streamers in CO2 differed considerably from that in air. The onset delay time of streamer discharge was measured and statistically processed based on previous studies of streamer onset processes. Findings indicated an increase in the discharge delay time and its dispersion when N2 was added to CO2, which indicated that variations in the initial electron content affected the inception process of streamer discharge.
Multi-material single-vat dual-wavelength DLP 4D printing of shape memory polymers
Authors: Kröger Finn , Schulte Lennard , Spiegel Christoph A , Vazquez-Martel Clara , Blasco Eva
Published: December 2024

Shape memory polymers are a fascinating class of responsive materials with potential in various fields, especially when combined with precise structuring by three-dimensional (3D) printing strategies such as digital light processing (DLP). However, such 3D printing techniques are usually limited to homogeneous single material four-dimensional (4D) structures restricting potential applicability. In this study we present a dual-wavelength multi-material DLP-based strategy for the fabrication of 4D multi-material structures with a spatial controllable shape memory effect from a single ink formulation. To achieve this, we designed an ink system, allowing generation of static as well as responsive parts depending on the applied curing wavelength with a high spatial control. Specifically, the multi-material ink formulations are composed of epoxide-based, (meth)acrylate-based monomers and a radical photoinitiator—providing appropriate selectivity of the polymerization mechanism. A germanium-based derivative has been selected as a suitable radical photoinitiator active in the blue wavelength regime (460 nm), enabling the exclusive formation of poly(meth)acrylate-based networks exhibiting shape memory properties. When printing with UV light (365 nm), simultaneous formation of epoxy and polymethacrylate networks results in a non-responsive material. Finally, by exploiting these capabilities, the fabrication of multi-material 4D structures with spatially controllable shape memory properties is successfully demonstrated.
Investigation into vibration filtering for reducing friction loss of ultrasonic motors through a numerical approach
Authors: Liao Xinxin , Perriard Yves
Published: December 2024

Ultrasonic motors (UMs) have emerged as a leading solution for actuators in biomedical equipment, aerospace applications, and other fields, owing to their distinct advantages, such as compact structures and self-locking ability. The operating principle of nearly all UMs heavily relies on friction coupling. Excluding material fatigue, friction loss is the primary factor affecting the UMs’ service life. To address this challenge, we propose, for the first time, the integration of vibration filtering into UMs to minimize friction loss during operation. The core innovation of this study involves partitioning the mover into two components: the primary mover and the secondary mover, connected by a flexible mechanism. The lightweight secondary mover remains in contact with the vibrator, while the primary mover contains the majority of the mover’s mass. The flexible mechanism serves as a filter, effectively preventing the transmission of harmonic vibrations, which are known to contribute to friction loss, from the secondary mover to the primary mover. By developing a generalized kinematic model for UMs, we systematically examined the feasibility of our approach with different parameters. Our findings demonstrate that, under a preload of 100 N, friction loss can be reduced by approximately 5 times. Although this technique introduces additional structural complexity, we contend that it holds heuristic significance for enhancing the efficiency of UMs, despite still being at the proof-of-concept level.
Deep learning bimodal frequency-selective digital holography by using a confocal dual-beam setup
Authors: Zhang Wanbin , Ren Yanchen , Feng Yijian , Sun Xiangdong , Hu Jiangnan , Xing Weiyong , Zhang Zhanjun
Published: December 2024

This paper proposes a bimodal digital holography technique based on deep learning, marking the first application of neural networks in frequency-selective holographic reconstruction. The method achieves dual-channel mixed-mode recording and super-resolution separation reconstruction, enabling simultaneous multimodal holography and enhancing wavefront acquisition efficiency. Direct current and conjugate terms are effectively suppressed, allowing coherent and incoherent holography integration. Experiments in overlapping and non-overlapping modes with confocal dual viewpoints confirm the method’s fidelity in isolating target wavefront spectra and demonstrate improved resolution after deep learning reconstruction. This technique offers broad potential in multimodal compressed holography, super-resolution, and extended field-of-view imaging.
Adsorption behavior of toxic nitrogen-containing gas molecules on GeC monolayer for the sensitive and reusable gas sensors: first-principles calculations
Authors: Thajitr W , Busayaporn W , Sukkabot W
Published: December 2024

Using the first-principles calculations, the gas sensing properties of GeC monolayer are analyzed to explore the possibilities in the toxic nitrogen-containing molecular sensors to detect NH3, NO2 and NO molecules. The adsorption behavior is computed under different stable adsorption configurations. NH3 is physically adsorbed on GeC monolayer with modest adsorption energies (Eads = −0.487 eV). NO2 is chemisorbed on GeC monolayer with Eads of −0.770 eV. NO is either physisorbed or chemisorbed on GeC monolayer with Eads of −0.437 eV or −0.605 eV depending on the stable adsorption configurations. NO2 and NO molecule dramatically change the electronic properties of GeC monolayer, while NH3 molecule barely modifies those of GeC monolayer. Because of the change in the electric conductivity, the descending order of the sensitivity is NO2 > NO > NH3. Finally, the quick recovery times are found for all molecules which determine the worth of reusability of a sensing material.
Topological characterization of [n]-triangulenes through degree-based molecular descriptors with the prediction to π-electron energy
Authors: K Jyothish , Roy S
Published: December 2024

Triangulene and its π-extended homologues are a family of polycyclic aromatic hydrocarbons with a peculiar chemical structure. They are recognized for their intricate structural configurations and electrical properties, which make them a promising material for potential uses in spintronics. They are built of benzenoid rings fused in a triangular manner. Topological indices are widely utilized as graph theoretical measures for evaluating the physicochemical properties of polycyclic aromatic hydrocarbons by analyzing their molecular structures, makes them hold a significant position in the domain of mathematical and computational chemistry. In this study, a mathematical exploration of topological indices of [n]-triangulenes has been done to establish a comprehensive understanding of their applications and significance. Generalized expressions for topological indices have been computed, and their predictive power for various physicochemical properties has been studied using statistical methods. Also, a quantitative structure-property relationship analysis of [n]-triangulene's energetic characteristics has been performed. Moreover, a generalized algebraic expression to predict the π-electron energy of [n]-triangulene structure has been derived.
Analysis of air and vacuum annealing on microstructural, optical and electrical characteristics of In2O3 layers for gas sensors
Authors: Suthar Kamlesh , Suthar D. , Sharma Ritika , Panwar S. , Himanshu Himanshu , Purohit L.P. , Dhaka M.S.
Published: December 2024

With consideration of significant potential of metal oxides in the effective gas sensing applications, herein, an assessment of air and vacuum annealing to the physical characteristics of In2O3 (Indium Oxide) layers is meticulously unveiled. Development of 550 nm thin In2O3 films on glass and ITO (Indium doped Tin oxide) coated substrates is accomplished by means of electron beam evaporation technique. An annealing treatment on grown In2O3 layers is executed at 300 °C, 375 °C and 450 °C for one hour in air and vacuum conditions followed by their subsequent characterizations using X-ray diffractometer, UV-Vis spectrophotometer, source meter, scanning electron microscope, and energy dispersive spectroscope tools. The crystallite size corresponding to predominant cubic peak (222) is obtained in 23-33 nm range for both types of films and observed least at 450 °C. Optical analysis exhibited that In2O3 films showed maximum transmittance of ~90% in visible region whereas band gap is measured within the range 2.20-3.50 eV. The electrical measurements unveiled Ohmic nature of films contacts where resistivity of In2O3 layers is found to be enhanced with air and vacuum annealing temperature. The morphological micrographs indicate uniform In2O3 films deposition with nanospherical grains and EDS patterns exhibited In and O peaks ensuring successful deposition of n-type In2O3 films with In richness and O vacancies. The gas sensor fabricated by using In2O3 films annealed in air at 450 °C is assessed for detection of H2S gas which showed gas response and response time of 1.08 and 38 seconds, respectively.
RSP-UV: real-time sampling-based path planning method for unmanned vehicles
Authors: Zhou Rui , Zhang Chuanwei , Zhao Ruiqi , Zhang Tianle
Published: December 2024

The Rapidly-exploring Random Trees Star (RRT*) is widely used in unmanned vehicle path planning. However, it suffers from excessive sampling randomness, long search time and not capable of dynamic obstacle avoidance. This is not only fatal to safety, but also detrimental to smooth driving. We propose a real-time sampling-based path planning method for unmanned vehicles (RSP-UV) that systematically solves these problems. To address the problem of excessive sampling randomness, we formulate a partitioned sampling strategy and limit the density of sampling points. It reduces the sampling time to a certain extent. Additionally, we design a fuzzy controller to adjust the scale factor of the Dynamic Window Approach (DWA) evaluation function to optimise the local path and improve the dynamic obstacle avoidance efficiency. Fusing the improved RRT* and the improved DWA, the global path output from the improved RRT* is used as the bootstrap path for the improved DWA. Besides, the return path set rule is made to avoid the backtracking phenomenon. This improves the reliability and asymptotic optimality of the final path. Simulation experiments show that the trajectories planned by RSP-UV outperform the three compared methods, the similar method, ORRT*-DWA and MTAR. Real experiments show that the average path length of RSP-UV is reduced by 2.26%, 3.03%, and 3.33% compared to the other three methods, respectively. The average planning time of RSP-UV is reduced by 7.16%, 2.15% and 8.78% compared to the other three methods, respectively. RSP-UV not only ensures the success of path planning but also excels in real-time and adaptability. The paths formed by RSP-UV are cheaper and safer.
Lime and marble deposits mapping and estimation through deep neural layers-random forest merger and remote sensing imagery
Authors: Jan Nazir , Minallah Nasru , Sher Madiha , Khan Shahid , Gohar Neelam , Khan Salahuddin
Published: December 2024

Lime and marble are sedimentary (carbonate) rocks, mainly composed of calcite and dolomite as major ingredients. Calcite (CaCO3) and dolomite (MgCO3) offer excellent reflection in visible and short-wave infrared bands (0.4 to 2.5 μm), which distinguish them from other rock types and makes them a solid application area for multispectral sentinel-2 sensors. In this study, the monumental deposits of carbonated rocks of the intended study region are mapped and estimated with better accuracy by using a novel Deep Neural Layers-Random Forest merger model and Sentinel-2 imagery. We used ArcGIS 10.5 to prepare a high-quality classified map of the study regions, which can be used further to effectively and efficiently reach out and extract those deposits. The proposed model, trained on a locally generated dataset, containing 134,897 pixels of size 10 m, mapped the deposits with 0.95 accuracy (kappa coefficient 0.94), which is 70% of the total mineral deposits of the study regions. The proposed model is the improved version of a prior experimented model consisting of convolution layers and dense layers only, whose accuracy was 0.93. The experimental outcomes of the study stood successful in finding the optimum combination of hyperparameters for the AI models used, to delineate mineralization zones with precision, focusing on carbonate in particular.
XGBoost-enabled low-complexity approach for signal integrity assessment in coherent communication systems
Authors: Jha Dhirendra Kumar , Mishra Jitendra K
Published: December 2024

Error vector magnitude (EVM) provides critical information for assessing signal integrity and system performance in optical communication systems. In this research, a regression approach using boosting algorithms is developed to retrieve EVM information from complex signal constellation structures applicable to various modulation formats. Amplitude histograms are created and collected at different OSNR levels, launch powers, and transmission distances using an offline preprocessing approach. The impact of various evaluation techniques, including mean absolute error, coefficient of determination, root mean square error (RMSE), and mean absolute percentage error (MAPE) is discussed in detail. The results show that the proposed extreme gradient boosting framework considerably increases estimation precision compared to categorical boosting and light gradient boosting machine, especially under diverse transmission conditions, with MAPE staying below 1.7% and RMSE below 0.5, thereby enhancing overall performance monitoring in optical communication systems. This research provides a comprehensive and accurate representation of the proposed EVM estimation technique, making it a valuable resource for the development of advanced optical performance monitoring systems in the future.
Novel structure of Fin-iTFET with main gate and source metal formed simultaneously while control gate and drain formed simultaneously
Authors: Lin Jyi-Tsong , Lin Yung-Hsin
Published: December 2024

In this paper, we propose a new structure for Fin-iTFET where the main gate and source metal are formed simultaneously, and the control gate and drain are formed simultaneously. The process used for the fabrication is simple, cost-effective, and fully compact with conventional CMOS technology. With the help of a control gate, our Fin-iTFET can achieve a steep subthreshold swing (SSavg) and a high I
ON/I
OFF ratio. Using Sentaurus TCAD simulations, we confirm that the current transport mechanism of our Fin-iTFET is based on band-to-band line-tunneling, which enhances the ON current (I
ON) and mitigates leakage with a reduced trap-assisted tunneling (TAT) effect. Instead of relying on dopant implantations and thermal annealing, we utilize a metal-semiconductor Schottky junction to enhance the minority carrier concentration at the source end, increase band bending, increase the overlap between the conduction band and valence band, increase the vertical electric field, and thereby increase the line tunneling generation rates, ultimately enhancing the ON current of the device. The simulations show that the device exhibits an SSavg of 13.6 mV dec−1 with an I
ON/I
OFF ratio of 109 at V
D = −0.2 V and V
CG = 0.2 V. In summary, our Fin-iTFET can achieve excellent electrical performance at low power supply voltages.
Compton scattering from proton pairs – illustrating weak and strong measurements
Authors: Karlsson Erik B
Published: December 2024

Neutrons interacting with protons in Compton scattering is here chosen as an example of a non-trivial quantum measurement. It illustrates a situation where a probe particle makes an observation (a weak measurement) of the studied protons, preparing for a final state in which one of them takes up the recoil in the collision. The proton is ejected during a strong (projective) measurement that selects one particular momentum value out of the proton’s initial distribution of momentum states. This course of events in the measurement process is evidenced by the observation that destructive interference appears during the weak interaction stage which leads to a strongly reduced neutron cross section for the proton system.
Frequency chirping in the early stage of a near-threshold bump-on-tail instability
Authors: Qu Z.S. , Garbet X. , Hezaveh H.
Published: December 2024

It has been shown that the mode amplitude and frequency evolution in the early non-linear stage of a near-threshold bump-on-tail system can be reproduced by solving the linear dispersion relationship at each time step using the non-linearly modified distribution function at an earlier time. The dispersion relationship gives two solutions with departing frequencies almost immediately after the flattening of the distribution function starts to cancel out the drive. One can therefore attribute the early onset of the chirping directly to the modification of the underlying dispersion relationship. The existence of the two waves is because of the beam branch of the beam-plasma instabilities created by the perturbed distribution function. After the two chirping branches are formed, their frequencies are locked to the location of the peaks in the nonlinear distribution function, while the peaks are pushed forwards by beating itself. The transition from the beating-and-chirping scenario to chirping with hole-clump pair creation is found to be determined by the overlapping criterion of the two phase-space islands created by the two chirping branches.
Investigation of two-dimensional radio-frequency sheath properties using a microscale fluid model
Authors: Kohno H. , Myra J.R.
Published: December 2024

In previous work (Kohno and Myra 2023 Comput. Phys. Commun.
291 108841), we developed a numerical scheme based on a two-dimensional microscale radio-frequency (RF) sheath model with periodically curved wall boundaries. Here, we expand the capability of this scheme through modification of the boundary conditions (BCs) on the conducting walls, which allows the ion flow to turn back to the plasma at locations on the walls where the electromagnetic force on the ions is reversed from its usual direction. Numerical simulations are carried out to investigate the dependences of the surface-integrated admittances on the wall bump height, ion magnetization, ion mobility, and the magnetic field angle, and to visualize the sheath structures in several cases. One of the main results is the ion cyclotron admittance resonance observed under the condition of low ion mobility (high normalized frequency). It is shown that the amplitude of the resonance peak depends on the wall bump height and the ion velocity is reversed on the sides of the bump in an RF cycle for the resonance cases. Furthermore, the differences in the admittances between the one- and two-dimensional microscale models are assessed for the purpose of understanding non-locality of the sheath near the wall surface for the parameters considered in this study. This information will be essential for improving the sheath BC for macroscale calculations in the future.
Research on enhanced oil recovery of super heavy oil based on FCD technology
Authors: Yang Huijuan , Shao Fengsheng , Sun Nan , Shen Qun
Published: December 2024

Horizontal well technology is widely used in CSS (Cyclic Steam Stimulation) and SAGD (Steam Assisted Gravity Drainage) in super-heavy oil development. With the increase of CSS cycles, three contradictions are increasingly faced: first, the issue of non-conformance of horizontal section; Second, the horizontal well is susceptible to steam breakthrough and SAGD steam chamber during production. Third, the issue of higher cycle lower efficiency. FCD (Flow Control Devices) technology is a kind of technology that can realize the artificial control of downhole steam, oil, and water flow. The flow control devices and sand control string are integrated, and the production string is run into the original well to achieve uniform steam injection and fluid production, inhibit steam breakthrough, improve production profile, and increase oil well production. In this paper, the FCD technology is introduced briefly, and then the application of FCD technology in major oil fields, both domestic and overseas, is discussed. Finally, the field practice of FCD technology in enhanced oil recovery of Liao He Oilfield Special oil development Company is discussed.
Integral quantization in the quantum configuration space
Authors: Góźdź A. , Góźdź M. , Pȩdrak A.
Published: December 2024

Quantum spacetime in which time is considered on the same footing as other observables is a part of the quantum configuration space. In such space a natural geometry is generated by the transition amplitudes among quantum configuration space points. It is shown, that a good candidate for quantization of extended (plus time) classical configuration spaces is integral quantization. This quantization is compatible with the notion of quantum time. The most basic features of this quantization are presented.
Quantum singularities in a solvable toy model
Authors: Znojil Miloslav
Published: December 2024

Via elementary examples it is demonstrated that the singularities of classical physics (sampled by the Big Bang in cosmology) need not necessarily get smeared out after quantization. It is proposed that the role of quantum singularities can be played by the so called Kato’s exceptional-point spectral degeneracies.
Relationship between Φ4-matrix model and N-body harmonic oscillator or Calogero-Moser model
Authors: Grosse H , Kanomata N , Sako A , Wulkenhaar R
Published: December 2024

We study some Hermitian Φ4-matrix model and some real symmetric Φ4-matrix model whose kinetic terms are given by Tr(EΦ2), where E is a positive diagonal matrix without degenerate eigenvalues. We show that the partition functions of these matrix models correspond to zero-energy solutions of a Schödinger type equation with N-body harmonic oscillator Hamiltonian and Calogero-Moser Hamiltonian, respectively. The first half of this paper is primarily a review of previous work of us. The discussion of the properties of zero-energy solutions and the discussion of systems of differential equations satisfied by partition functions derived from the Virasoro algebra in the latter half of this paper contain novel material.
Generalization of the Coleman-Mandula theorem and the ring paradigm
Authors: Novák J
Published: December 2024

One of the biggest open problems in cosmology is to explain the accelerated expansion of the Universe in the last 5 billion years. There were attempts to solve it classically, but one could also use quantum gravity. We introduce a new approach to the quantization of gravity, called the ring paradigm, according to which graviton is a phonon on a dynamical grid. We obtain, after the application to cosmology, a new model of dark energy, inside which we solve the old problem of the cosmological constant. The only way how to conceptually verify the ring paradigm is to show that there exists a certain generalization of the Coleman-Mandula theorem.
On the construction of the coherent states of the semiconfined harmonic oscillator with a position-dependent effective mass
Authors: Nagiyev S.M. , Jafarov E.I.
Published: December 2024

We present details of the method for constructing the coherent states of the quantum harmonic oscillator model that exhibits the semiconfinement effect due to a specific change of its mass by position. Its energy spectrum completely overlaps with the Hermite oscillator energy spectrum, whereas the wavefunctions of the stationary states are expressed via the generalized Laguerre polynomials. Two different methods have been applied to compute the coherent states. They are generalized and Barut-Girardello coherent states methods. In both cases, the exact expressions have been obtained. We also analyzed some limit cases, under which the constructed coherent states completely recover the coherent states of the Hermite oscillator.
Generalized exchange operators for a system of spin-1 particles
Authors: Jeudy Charlie , Rouleux Michel
Published: December 2024

The irreps

(

S
U

(
2
)
,

H

,
U
)

of SU(2) of dimension (2S + 1)N, i.e. operators acting on the space

H

=

H

N

=

C

(
2
S
+
1

)
N

of N identical particles with spin S, are described by Clebsch-Gordan decomposition into inequivalent irreps. In the special case S = 1/2, Dirac [1] discovered that there is another rep given by

(

S

(
N
)
,

H

,
V
)

where

S

(
N
)

is the permutation group, Thus, the standard “linear” Hamiltonian, or Heisenberg interaction Hamiltonian

H

0

=

∑

1
≤
i
≤
N

S

→

i

⋅

S

→

j

, where

σ

→

i

=
2

S

→

i

is the vector of Pauli matrices, can be interpreted as the sum of the “Exchange Operators” Pij
between particles i and j. Schrödinger [3] generalized to higher spin numbers S the Exchange Operator

P

i
j

=

P

S

(

S

→

i

⋅

S

→

j

)

as a polynomial of degree 2S in

S

→

i

⋅

S

→

j

. This we call the P-representation. There is another rep induced by the one particle permutation of states operators

Q

∼

α

, which we call the Q-rep. Our main purpose is to write some physical Hamiltonians for a few particles in the P- or Q-rep and compute their spectrum. The simplest case where there are as many particles as available states for the spin operator along the z-axis, i.e. N = 2S + 1 = 3, see Weyl [4] or Hamermesh [5]. Finally, we consider the relationship between permutations and rotation invariance when S = 1/2 and S = 1.
Data-driven optimization of material composition and casting processes for large ferritic nodular cast iron components in wind turbines
Authors: Su Fei , Wang Donghong , Xue Jing , Deng Xiaoming , Gong Qianhai , Xia Xiaojiang , Su Xianglin , Shu Da
Published: December 2024

This study addresses the challenges of producing large-scale wind turbine components by proposing an optimization scheme for the material properties and casting processes of ductile cast iron. The study integrates experimental data with JMatPro calculations to establish a comprehensive database of 1, 139 ferritic nodular cast iron samples. Using machine learning and multi-objective optimization, an optimized composition was developed, and Pareto front solutions were achieved with performance significantly surpassing QT400-18. The AI-CAST platform was then applied to refine the casting process for a 6 MW wind turbine hub, reducing internal defects to 2, 738.52 mm³ and decreasing loose defects by 83.68%. This integrated approach not only enhances material performance and casting quality but also offers significant cost savings, suggesting broad applicability for improved production efficiency in the casting industry.
Numerical simulation of underwater explosive shock wave with gas layer charge
Authors: Hao Hongrui , Lu Xi , Liang Zhengang
Published: December 2024

To investigate the effect of the gas layer on the explosive’s underwater explosion shock wave load, based on AUTUODYN kinetic analysis software, we establish a one-dimensional underwater explosion numerical simulation model with a gas layer charge and study underwater explosion with a gas layer charge on the impact of the peak pressure and specific impulse of the shock wave underwater explosion. The results show that the gas’s low impedance and the continuous reciprocal reflection of the shock wave in the layer of the shock wave in the water led to a lower pressure Peak pressure of the shock wave in the water and its post-wave oscillatory decay waveform. With the increase of the uncoupling coefficient, the peak pressure of the shock wave in the water decreases, and the specific impulse increases and then decreases, through the range of 5∼1, 000 kg of TNT spherical charge underwater explosion calculations, to verify the reliability of the conclusions. The study’s conclusion shows that applying an underwater blast protection project with a gas layer charge should be reasonably designed for gas layer thickness to avoid the enhancement of the impulse but increase the harm of the shock wave.
Gas layer charge influence law study of underwater explosion bubble pulsation
Authors: Liu Yuchen , Yan Haimin , Lu Xi , Guo Cean
Published: December 2024

To discuss the influence of the gas layer on underwater explosion load, the influence of gas layer thickness on bubble pulsation period maximum radius, pressure peak value, and specific impulse during underwater explosion was first discussed. A simulation model of underwater explosion with gas layer charge is established by numerical simulation method, and the influence law of gas layer on the pulsation of underwater explosion bubble is calculated and analyzed. The results show that the pulsation period and maximum radius of the underwater explosion bubble increase with the increase of gas layer thickness. The peak value of bubble pulsation pressure decreases, while the specific impulse increases first and then decreases. The research conclusion shows that in a certain gas layer, the damage risk of protective structure may be increased due to the increase of pulsating pressure ratio impulse or the resonance between pulsating frequency and structure.
Effect of tungsten carbide content on the wear performance of plasma-clad nickel-based tungsten carbide coatings
Authors: Cao Yichen , Li Xinshuo , Dong Haotian , Wang Guanghong , Zou Wei
Published: December 2024

The performance demands for cutter rings in tunnel excavation have increased, necessitating improved wear and corrosion resistance of their surfaces. Plasma-clad tungsten carbide coatings can significantly enhance these properties. This study is one of the first to systematically investigate the wear performance of plasma-clad nickel-based coatings with specific tungsten carbide (WC) content (50% and 60%) under dry wear conditions, using an in-depth comparative analysis of wear mechanisms. Through experimental design, wear coefficient and volume analysis, and performance evaluation, we investigate the mechanical properties and microstructure of the coatings before and after wear. Techniques such as metallographic analysis, hardness evaluation, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used. Additionally, this study introduces an optimized testing protocol for analyzing wear behavior under varying loads, contributing to a more precise understanding of how WC content impacts wear resistance. Results show that variations in load, tungsten carbide content, and operating conditions impact the coating’s structure and wear performance. The primary wear mechanisms observed were abrasive and adhesive wear. An optimal tungsten carbide content provided superior wear resistance, with a wear coefficient 1.5 times higher and a wear volume half that of coatings with excessive tungsten carbide. These findings offer valuable insights for applying plasma cladding technology to develop high-wear-resistant coatings.
Analysis of temperature field in gun barrel under different firing numbers
Authors: Yang Yanyan , Yang Li
Published: December 2024

To examine the impact of the temperature field created by the thermal shock of high-temperature propellant gas in the barrel during firing on the dependability of the gun’s lifespan, a finite element model of a gun barrel was created by using finite element software. Under single and continuous firing settings, the distribution law of the barrel temperature field was examined, and the convective heat transfer mechanism on the inner and outer walls of the barrel was simulated by using nonlinear transient thermodynamic theory. This establishes the groundwork for future investigations on the dependability of gun barrel life.
First motional stark effect measurements at Wendelstein 7-X
Authors: Zanini Marco , Ford Oliver , Bannmann Sebastian , Kügler Jörn , Poloskei Peter Zsolt , Romba Thilo , Wolf Robert ,   W7-X Team
Published: December 2024

The rotational transform plays a crucial role in magnetic
confinement devices and its profile is directly related to stability
and confinement properties. A popular way to assess the rotational
transform profile is using a Motional Stark Effect diagnostic
system, which relies on the splitting of the Balmer alpha emission,
due to the interaction between a particle beam and the plasma. A
prototype diagnostic was installed at the stellarator Wendelstein
7-X, in order to demonstrate that such a diagnostic can be operated
in this device. This work presents the diagnostic design and
preliminary measurements as well as the calibration procedures
necessary to deal with the extra complexity of measuring
polarisation via an aluminium mirror. Qualitative agreement with
simulations is shown in the variation of the measured polarisation
angle over wavelength. A small but significant change in the
measured angle is seen with changes in the plasma beta. While of a
similar order to that expected, insufficient sensitivity of the
prototype precludes a quantitative match to the prediction. The
required changes to sufficiently improve the sensitivity to achieve
this in future experiments is discussed.
Performance evaluation of an RFSoC operating in a 1.25 Tesla magnetic field
Authors: Ruckman L. , Dragone A. , Herbst R.
Published: December 2024

The Belle II experiment at the SuperKEKB collider is
preparing for an upgrade after 2027–2028 to handle higher
luminosity and increased background rates. A Radio Frequency
System-on-Chip (RFSoC) has been identified as a potential candidate
for a common front-end upgrade for subsystems requiring high-speed
waveform digitization. The RFSoC's ADC and DAC channels were tested
across various magnetic field strengths and a few different field
orientations. Power consumption and boot memory functionality were
also assessed. Results indicate stable operation with negligible
performance degradation, suggesting the RFSoC's viability for
high-speed digitization tasks in high magnetic field environments.
Housing for millions without new buildings? An analysis of the theoretical housing potential of under-occupied dwellings in the European building stock
Authors: Lage Jonas , Cordroch Luisa , Thema Johannes , Vondung Florin , Schöpf David
Published: December 2024

The standard response to the shortage of housing across the political spectrum is to build new housing units. From an environmental perspective, there is a need to decarbonise the housing sector as quickly as possible and to reduce land and resource consumption. This contradiction could be resolved by making more efficient use of dwellings that are under-occupied (for example, after children have moved out). In this article, we analyse the theoretical housing potential of under-occupied living space. To this end, we use established occupancy regulations of Swiss cooperatives and municipal housing authorities, where the number of residents must always be at least equal to the number of rooms minus one or minus two. This defines an upper limit for ‘needs-based living’ that has been tested in practice and is comparatively broadly legitimised. Using this threshold, and based on Data from the EU Statistics on Income and Living Conditions, we identify a theoretical housing potential in the EU stock of approximately 152 million rooms. This implies a theoretical space in the building stock for 50 million additional three-room flats, which equates to housing for 100 million people or 23 % of the EU population. Significant potential exists in all types of regions: cities, towns and rural areas. The under-occupancy is lower in countries with a higher share of small and medium sized flats, which indicates a high influence of the infrastructure on the occupancy. A comparison with the occupancy in Swiss housing markets that have minimum occupancy requirements implemented suggests that a large part of the theoretical potential could be realized by shaping infrastructural and market conditions. We conclude that housing politics should focus on the development of affordable and attractive alternatives for older people and smaller households in order to free up dwellings for families and address social and ecological problems in the housing market simultaneously.
Snow-cover seasonality in Kyrgyzstan: variation and change over 20 years (2001–2021) as observed by the MODIS Terra snow product
Authors: Henebry Geoffrey M , Tomaszewska Monika A
Published: December 2024

Snow seasonality is expected to change as a result of planetary warming. Yet, how the timings of snow seasons have already shifted in mountain environments can be counterintuitive. Here, we update our 2018 analyses of snow seasonality in Kyrgyzstan (KG) using more data and improved methods. Using two decades of MODIS snow-cover data, we investigated trends in four snow seasonality metrics: first date of snow (FDoS); last date of snow (LDoS); duration of the snow season (DoSS); and snow-covered days (SCDs). Our novel but conservative nonparametric approach analyzed trends within elevation ranges at two administrative levels: oblast and rayon. To attenuate the risk of false-positive trends, we reported as ‘notable’ only those significant (p < 0.05) nonparametric trends that were also (i) strongly asymmetric (at least twice as many significant pixels in one direction) within an elevational range of the oblast or rayon and (ii) covering at least 5% of the elevation range in oblast or rayon and more than 10 pixels. We used both simple and advanced snow-cover metrics, with the latter exploiting the within-composite chronobyte detail available in the MOD10A2.061 product. We found notable trends to earlier FDoS below 3000 m in western KG and more SCD between 1500–3500 m in western KG. We also found the expected notable trends towards earlier LDoS at both oblast and rayon levels. In northwestern KG, DoSS was notably longer <3000 m, but notably shorter at 3500–4000 m. In our 2018 analyses, we found at the national level 160% more area trending to earlier FDoS than to earlier LDoS. Our comprehensive updated trend analysis was designed to be more conservative. It revealed more area (106%–130%) trending to earlier FDoS than earlier LDoS, reinforcing the counterintuitive finding of longer snow seasons starting earlier at lower elevations.
Cell membrane-camouflaged nanoparticles activate fibroblast-myofibroblast transition to promote skin wound healing
Authors: Jia Qi , Ding Yijuan , Su Ziwen , Chen Heying , Ye Jialing , Xie Dafeng , Wu Yubo , He Haiyan , Peng Yanlin , Ni Yilu
Published: December 2024

The fibroblast-myofibroblast transition marked by extracellular matrix (ECM) secretion and contraction of actomyosin-based stress fibers, plays central roles in the wound healing process. This work aims to utilize the cell membrane-based nanoplatform to improve the outcomes of dysregulated wound healing. The cell membranes of myofibroblasts isolated from mouse skin are used as the camouflage for gold nanoparticles loaded with IL-4 cytokine. The membrane-modified nanoparticles show effective in situ clearance of bacterial infection, and act as the activator in IL-4Rα signaling pathway to induce pro-inflammatory M1 macrophages into the anti-inflammatory M2 phenotype. Thus, the poor bacteria-clearance and non-stop inflammation in refractory wounds are improved and accelerated. Furthermore, the nanoplatform releases myofibroblast membranes to propel primitive fibroblasts toward the fibroblast-myofibroblast transition in an epigenetic manner. Matrix-production, vascularization, and epithelial regeneration are then initiated, leading to the satisfactory wound closure. Our study devises a new strategy for activating fibroblasts into myofibroblasts under prolonged and continuous exposure to the fibrotic environment, and develops a promising biomimetic nanoplatform for effective treatment of dysregulated chronic wound healing.