bluuebunny/crossref_metadata_2025 huggingface dataset:
Statistical distribution of surface elevation by using quadratic forms of normal random variables
Authors: Gao Zhe , Teng Yunfei , Zhang Cheng , Wang Lei , Cheng Liang
Published: October 2024

This paper is concerned with the statistical properties of surface elevation, which is crucial for the design and operation of marine and coastal structures and is helpful to the prediction of rogue waves. A semi-analytic quadratic model is proposed to describe the statistical distribution of surface elevation by using the theory of quadratic forms of normal random variables, in which the characteristic function and cumulants are given in analytical form, and the probability density is obtained by the numerical inversion of the characteristic function using the fast Fourier transform algorithm. Compared with Monte Carlo simulations, the quadratic model presents excellent performance in describing the probability density function of surface elevation, especially at the tails, for varying degrees of steepness, bandwidth, and directional spreading in both finite and infinite water depth. The effect of these parameters that characterize sea states on the statistical properties of surface elevation is also investigated. Through a comparative study, the quadratic model is superior to previously existing theoretical models.
Electric dipole polarizabilities and tune-out wavelengths for 23S1 and 33S1 states of Be2+
Authors: Wu Fang-Fei , Qi Xiao-Qiu , Chen Ai-Xi
Published: October 2024

The electric dipole polarizabilities and the tune-out wavelengths for the n3S1 (n = 2, 3) states of Be2+ are determined through the application of the relativistic full-configuration-interaction approach. Our calculations directly integrate the mass shift operator into the Dirac–Coulomb–Breit Hamiltonian and further assess the quantum electrodynamics (QED) correction to the dynamic dipole polarizabilities using perturbation theory. The results reveal that the static electric dipole polarizability of the 23S1 and 33S1 states, as well as the 93 nm tune-out wavelength of the 23S1 state and the 238 nm tune-out wavelength of the 33S1 state, exhibits a high sensitivity to QED correction, which exceeds 80 ppm, providing a sensitive test for atomic structure theory.
Wide-bandgap semiconductor SiC-based memristors fabricated entirely by electron beam evaporation for artificial synapses
Authors: Qin Haiming , Sun Shilei , He Nan , Zhang Pengchao , Chen Shuai , Han Cong , Hu Rui , Wu Jiawen , Shao Weijing , Saadi Mohamed , Zhang Hao , Hu Youde , Wang Xinpeng , Liu Yi , Zeng Liang , Tong Yi
Published: October 2024

The combination of high-performance materials and simplified multilayer fabrication processes can promote the rapid and high-quality development of memristors. In this work, we proposed wide-bandgap semiconductor silicon carbide (SiC)-based memristors fabricated entirely by electron beam evaporation technology. The Cu/SiC/Pt structure was fabricated on a 2-inch intrinsic silicon substrate, which can achieve a transition from volatility to non-volatility. Devices had a low and symmetric switching voltage of ±0.5 V, an endurance of >200 cycles, a retention of >103 s, an ON/OFF ratio of ∼103, and can achieve at least 6 different stable resistance states. The combined effects of traps and Cu conductive filaments caused the current to change abruptly during switching, while also possessing excellent synaptic plasticity and pulse programming ability. Our work demonstrated that wide-bandgap semiconductor SiC is a promising candidate for advanced memristors.
Pore collapse, shear bands, and hotspots using atomistics-consistent continuum models for RDX (1,3,5-trinitro-1,3,5-triazinane): Comparison with molecular dynamics calculations
Authors: Herrin Jacob , Tow Garrett , Brennan John , Larentzos James , Picu Catalin R. , Udaykumar H. S.
Published: October 2024

Shock-induced energy localization is a crucial mechanism for determining shock sensitivity of energetic materials (EMs). Hotspots, i.e., localized areas of elevated temperature, arise when shocks interact with defects (cracks, pores, and interfaces) in the EM microstructure. The ignition and growth of hotspots in a shocked energetic material contribute to rapid chemical reactions that can couple with the passing shock wave, potentially leading to a self-sustained detonation wave. Predictive models for shock-to-detonation transition must correctly capture hotspot dynamics, which demands high-fidelity material models for meso-scale calculations. In this work, we deploy atomistics-guided material models for the energetic crystal RDX (1,3,5-trinitro-1,3,5-triazinane) and perform tandem continuum and all-atom molecular dynamics (MD) simulations. The computational setup for the continuum and MD simulations are nearly identical. The material models used for the calculations are derived from MD data, particularly the equations of state, rate-dependent Johnson–Cook strength model, and pressure-dependent shear modulus and melting temperature. We show that a modified Johnson–Cook model that accounts for shear-induced localization at the pore surface is necessary to represent well—relative to MD as the ground truth—the inelastic response of the crystal under a range of shock conditions. A head-to-head comparison of continuum and atomistic calculations across several metrics of pore collapse and energy deposition demonstrates that the continuum calculations are in good overall agreement with MD. Therefore, this work provides improved RDX material models to perform physically accurate meso-scale simulations, to enhance understanding of hot spot formation, and to use meso-scale hot spot data to inform macro-scale shock simulations.
Tunable optically transparent graphene–ITO patterning-based millimeter-wave absorber
Authors: Shahzad Anjum , Chen Rui , Ahmed Shakeel , Naqvi Qaisar Abbas , Choudhury Pankaj Kumar , Ma Yungui
Published: October 2024

In this work, we demonstrated a multilayer millimeter-wave absorber capable of tuning the absorption frequency while simultaneously maintaining the optical transparency. It comprises indium tin oxide (ITO) as the bottom ground plane deposited over polyvinyl chloride (PVC) substrate over which a patterned ITO layer is formed. Above this ITO layer, a PVC spacer is put to isolate the upper graphene sandwich structure (GSS) comprising of two patterned graphene mediums separated by a diaphragm paper. The configuration shows the tunability of reflectance minima (which correspond to high absorptance of ≥ 98 %) in a frequency range of 92.5–97.5 GHz due to the adjustable bias voltage applied to GSS. Additionally, the designed absorber demonstrates adequate shielding effect, generally required for both commercial and military applications in the stated frequency range. This simultaneously configurable and optically transparent device has potential in multispectral and smart stealth technologies, particularly 6G applications.
Theoretical prediction on tetragonal Be2B monolayer as a well-balanced performance anode for lithium-ion batteries
Authors: Lu Zheng , Hu Rui , Cheng Hao , Liu Chun-Sheng , Ye Xiao-Juan
Published: October 2024

As one of the most important energy storage systems, lithium-ion batteries (LIBs) attract much attention recently. Materials composed of beryllium or boron, due to the lighter molar weight, offer natural advantages for high energy density anode of LIBs. Here, we propose a two-dimensional tetragonal Be2B (T-Be2B) and investigate the performance as a potential anode for LIBs. Through first-principles calculations, T-Be2B exhibits excellent thermal, dynamic, and mechanical stability. As a semiconductor material with the bandgap of 0.303 eV, T-Be2B shows a strong capability to adsorb Li atoms. Furthermore, T-Be2B monolayer demonstrates a low diffusion barrier of 0.26 eV, a moderate theoretical capacity of 929 mA h g−1, and an average open-circuit voltage of 0.88 V. Additionally, the presence of vacancy defects weakens the adsorption ability and migration behavior of Li on T-Be2B, which should be carefully handled in the experimental preparation process of T-Be2B monolayer. Based on these properties, the T-Be2B monolayer has significant potential as an anode material for LIBs.
Evaluating non-photochemical quenching (NPQ) kinetics and photosynthetic efficiency in cassava (Manihot esculenta) subjected to variable high light conditions
Authors: Nair Raji Sadasivan , Raju Saravanan , More Sanket Jijabrao , Puthur Jos Thomas , Makasana Jayanti , Ravi Velumani
Published: October 2024

Light intensity is a critical environmental factor influencing plant growth and development. To survive high light conditions, plants have evolved various protective mechanisms, including non-photochemical quenching (NPQ). However, NPQ can limit effective photosynthetic yield when transitioning to low light conditions. This phenomenon is underexplored in cassava (Manihot esculenta), a starchy storage root crop known for its high biological efficiency and climate resilience. To address this knowledge gap, we assessed the photoprotective abilities and growth responses of six cassava varieties under natural environmental light conditions (control) and intermittent high light (IHL) conditions by adding 900 μmol m−2 s−1 using full-spectrum LED lights, on top of the natural ambient daylight. Our results demonstrated a significant impact of light treatment on aboveground biomass, total crop biomass, chlorophyll a and b content, photosynthetic rate, and NPQ values during transitions from low to high light and vice versa. Notably, cassava variety ‘Sree Suvarna’ exhibited the highest yield under both control and IHL conditions. These findings suggest that screening cassava varieties for their ability to postpone photoinhibition and recover quickly from photoinhibition may enhance photosynthetic performance. Such strategies have important implications for improving the efficiency and resilience of cassava crops, ultimately contributing to sustainable agricultural productivity.
Response of white-tailed deer to removal of invasive wild pigs
Authors: McDonough Matthew T. , Gitzen Robert A. , Zenas Stephen J. , Smith Mark D. , VerCauteren Kurt C. , Ditchkoff Stephen S.
Published: October 2024

Context With the range expansion of invasive wild pigs (Sus scrofa) in North America during the past decades, there has been an increasing concern with how wild pigs affect native species. An abundance of research on their impacts has been through the lens of damage to anthropogenic resources and plant communities. However, quantitative research on how wild pigs affect populations of native animal species is an understudied topic. Aims Our goal was to assess how wild pigs affect white-tailed deer (Odocoileus virginianus) at a population level by measuring changes in deer abundance as wild pigs are removed. White-tailed deer are an economically valuable game species in North America, and negative impacts of wild pigs on their populations could have trickle-down impacts on conservation funding for all wildlife. Methods On three treatment areas (34.07–55.31 km2) and one control area (25.10 km2), we used N-mixture models to compare data from camera-trap surveys of white-tailed deer before and after wild pigs were removed from treatment areas. Key results We removed 1851 pigs from the treatment sites between May 2019 and March 2021. We found that wild pigs did not significantly affect white-tailed deer abundance, but that white-tailed deer were 1.12 (1.02–1.23; 95% CL) times as likely to be detected when the number of pigs removed was equal to our baseline population estimates compared with when no pigs were removed. Although results from similar analyses on separate age and sex classes of white-tailed deer exhibited similar results, analyses of impacts on immature males differed. Conclusions Our overall results are congruent with those of other research that suggest that wild pigs affect white-tailed deer behaviour at a local scale, although eliminating pigs from an area does not appear to quickly lead to increased abundance of deer. Implications Although the interspecific interactions between white-tailed deer and wild pigs are unlikely to lead to a decline in the population of white-tailed deer, removing wild pigs may decrease the behavioural implications of these interactions.
The MKK3 module integrates nitrate and light signals to modulate secondary dormancy in
Arabidopsis thaliana
Authors: Regnard Sarah , Otani Masahiko , Keruzore Marc , Teinturier Alizée , Blondel Marc , Kawakami Naoto , Krapp Anne , Colcombet Jean
Published: October 2024

Seed dormancy corresponds to a reversible blockage of germination. Primary dormancy is established during seed maturation, while secondary dormancy is set up on the dispersed seed, following an exposure to unfavorable factors. Both dormancies are relieved in response to environmental factors, such as light, nitrate, and coldness. Quantitive Trait Locus (QTL) analyses for preharvest sprouting identified MKK3 kinase in cereals as a player in dormancy control. Here, we showed that MKK3 also plays a role in secondary dormancy in
Arabidopsis
within a signaling module composed of MAP3K13/14/19/20, MKK3, and clade-C MAPKs. Seeds impaired in this module acquired heat-induced secondary dormancy more rapidly than wild-type (WT) seeds, and this dormancy is less sensitive to nitrate, a signal able to release dormancy. We also demonstrated that MPK7 was strongly activated in the seed during dormancy release, especially in response to light and nitrate. This activation was greatly reduced in
map3
k13/14/19/20
and
mkk3
mutants. Finally, we showed that the module was not regulated and apparently did not regulate the genes controlling abscisic acid/gibberellin acid hormone balance, one of the crucial mechanisms of seed dormancy control. Overall, our work identified a MAPK module controlling seed germination and enlarged the panel of functions of the MKK3-related modules in plants.
Isoform-specific C-terminal phosphorylation drives autoinhibition of Casein kinase 1
Authors: Harold Rachel L. , Tulsian Nikhil K. , Narasimamurthy Rajesh , Yaitanes Noelle , Ayala Hernandez Maria G. , Lee Hsiau-Wei , Crosby Priya , Tripathi Sarvind M. , Virshup David M. , Partch Carrie L.
Published: October 2024

Casein kinase 1δ (CK1δ) controls essential biological processes including circadian rhythms and wingless-related integration site (Wnt) signaling, but how its activity is regulated is not well understood. CK1δ is inhibited by autophosphorylation of its intrinsically disordered C-terminal tail. Two CK1 splice variants, δ1 and δ2, are known to have very different effects on circadian rhythms. These variants differ only in the last 16 residues of the tail, referred to as the extreme C termini (XCT), but with marked changes in potential phosphorylation sites. Here, we test whether the XCT of these variants have different effects in autoinhibition of the kinase. Using NMR and hydrogen/deuterium exchange mass spectrometry, we show that the δ1 XCT is preferentially phosphorylated by the kinase and the δ1 tail makes more extensive interactions across the kinase domain. Mutation of δ1-specific XCT phosphorylation sites increases kinase activity both in vitro and in cells and leads to changes in the circadian period, similar to what is reported in vivo. Mechanistically, loss of the phosphorylation sites in XCT disrupts tail interaction with the kinase domain. δ1 autoinhibition relies on conserved anion-binding sites around the CK1 active site, demonstrating a common mode of product inhibition of CK1δ. These findings demonstrate how a phosphorylation cycle controls the activity of this essential kinase.
Self-gravitating matter in stationary and axisymmetric black hole spacetimes
Authors: Kocherlakota Prashant , Narayan Ramesh
Published: October 2024

All black holes (BHs) in nature are expected to be described by the Kerr vacuum solution of general relativity. However, the Kerr BH interior contains several problematic features such as a Cauchy horizon, a curvature singularity, and a causality-violating region. Non-Kerr BH models, which are used to examine the genericity of these features, typically contain nontrivial matter content. When such self-gravitating matter is minimally-coupled to Einstein–Hilbert gravity, the Einstein equations can be directly used to investigate its physical properties. We examine here the properties of matter in a broad class of stationary and axisymmetric, geodesically-integrable BH spacetimes, and how they are linked to various features of the spacetime geometry. In these spacetimes, we find the matter to typically flow along timelike Killing orbits in the BH exterior, usually exhibiting differential rotation but sometimes additionally also non-rigid rotation. At a horizon, the matter rest-frame energy density,ε, and principal normal pressure,pn, are shown to necessarily satisfypn=−ϵ, implying that only specifictypesof matter can thread stationary event horizons (e.g. electromagnetic fields but not massless real scalar fields). Furthermore, we introduce Boyer–Lindquist-like coordinates for the nonstationary regions in the BH interior, which show the matter to be comoving with the interior cosmology. We also obtain simple expressions for the expansions of the ingoing and outgoing zero angular momentum null congruences and comment on the light-focussing behavior of the cosmology. Finally, we verify above results explicitly by working with a representative set of well-known BH spacetimes which contain various types of matter—scalar fields, electromagnetic fields, anisotropic fluids. Some spacetimes have singularities while others have regular interiors. In the exterior, the matter satisfies the weak energy condition. The framework developed here can be extended to cover more general spacetimes.
Non-linear charged dS spacetime and its thermodynamics and Schottky Anomaly
Authors: Zhen Hai-Long , Du Yun-Zhi , Li Huai-Fan , Zhang Li-Chun , Ma Yu-Bo
Published: October 2024

In this paper, firstly, the conditions and existence region for the coexistence of the black hole and cosmological horizons in Non-linear charged dS (NLC-dS) spacetime are discussed, subsequently, the thermodynamic quantities for which the boundary conditions are satisfied in spacetime in the coexistence region of the two horizons are discussed, and the effective thermodynamic quantities in the NLC-dS spacetime in the coexistence region with two horizons are presented. Based on these, the heat capacity in the coexistence region with two horizons is addressed, the behavior of the heat capacity in the NLC-dS spacetime in the aforementioned region is found to exhibit the characteristics of Schottky specific heat. In order to investigate the intrinsic reason of the heat capacity in spacetime, we regard the two horizons in the NLC-dS spacetime as two distinct energy levels, consequently, the microscopic particles at different horizons exhibit disparate energies. Using the heat capacity relationship between the two-energy levels in an ordinary thermodynamic system, the heat capacity in dS spacetime is discussed, it is observed that the behavior of the heat capacity is analogous to that of the two-energy levels in an ordinary thermodynamic system. The number of microscopic particles in the two-energy-level system are approximated by comparing the maximum value of the heat capacity of the system with the maximum value obtained by treating the two horizons in the NLC-dS spacetime as a two-energy-level system of two distinct energies. This conclusion reflects the quantum properties of the coexistence region with two horizons in the NLC-dS spacetime. It provides a new avenue for further study of the thermodynamic properties of black holes and the quantum properties of de Sitter spacetime.
Flattenicity as centrality estimator in p–Pb collisions simulated with PYTHIA/Angantyr
Authors: Ortiz Antonio , Bencédi Gyula , Fan Feng
Published: October 2024

In this paper, a centrality estimator based on flattenicity is studied using PYTHIA 8.312 Angantyr, whose existing implementation is enough to study the particle production in p–Pb collisions in the absence of medium effects. The number of binary nucleon–nucleon collisions for different centrality estimators are compared. The studies include forward multiplicity, forward flattenicity and midrapidity multiplicity. The results using flattenicity show the smallest deviations (<8%) with respect to the results which use impact parameter for centrality classes. On the other hand, the multiplicity-based estimators exhibit huge deviations (up to a factor 2) with respect to the results using impact parameter. The particle ratios (proton-to-pion and kaon-to-pion ratios) and nuclear modification factors as a function of p
T are also studied for the different centrality estimators. The studies presented here are relevant to help in the investigation of the plethora of effects, which have been reported by experiments at the Large Hadron Collider.
Smart dimensional quality assessment of embedded steel plates based on images and laser data fusion
Authors: Li Hangyu , Jiang Shang , Zhang Jian
Published: October 2024

Accurate and efficient positioning is critical to ensuring the dimensional quality assessment of embedded steel plates. However, traditional manual measurement methods struggle to efficiently measure and evaluate these plates. Vision-based measurement methods offer advantages such as high resolution, fast data acquisition, and processing speed, allowing accurate measurement of 2D coordinates. Light Detection and Ranging (LiDAR) can capture highly accurate point clouds, due to the unordered nature of point clouds, processing and analysis require significant computational resources. This paper proposes a method for smart 3D localization of embedded steel plates using image and laser data. (1) We introduce an improved rectangular diagonal constraint Harris corner detection method and achieve subpixel 2D corner detection of embedded plates based on deep learning:(2) given a calibrated camera-LiDAR, we develop a smart detection algorithm guided by 2D image bounding boxes, achieving 3D corner localization. In indoor testing and engineering applications, this method effectively ensures the dimensional quality of embedded steel plates. Compared to traditional manual inspection, the measurement efficiency reaches 10 min per station, with an accuracy of 2.12 mm.
In-situ measurement methods for microscale surface impurities in powder bed fusion: a review
Authors: Koca Ahmet , Hooshmand Helia , Leach Richard , Liu Mingyu
Published: October 2024

Despite ongoing improvements and optimisation efforts, the powder bed fusion (PBF) process continues to face challenges related to repeatability, robustness, and stability. These challenges can lead to the formation of microscale surface impurities on each layer, such as balling, spatter and surface pores, which can adversely affect the overall quality of the final part. The layer-by-layer fabrication approach in PBF offers an opportunity to assess fabrication quality in real-time by detecting these impurities at each layer during the manufacturing process through in-situ sensing methods. With advancements in sensing and computing technologies, there has been a significant increase in studies focused on developing in-situ methods for the real-time detection of surface impurities and feedback mechanisms. However, it is necessary to understand the effectiveness and capability of these in-situ methods in detecting microscale surface impurities, as well as to evaluate their potential advantages, drawbacks, and the existing gaps in the literature. This study first summarises the common microscale surface impurities and their potential impacts on part quality, including mechanical properties and surface finish. It then reviews the existing in-situ methods capable of detecting these microscale impurities, providing insights into the strengths and limitations of current techniques, and identifying gaps in the literature while suggesting directions for future research.
Adaptive IMU error correction algorithm for dual-antenna GNSS/IMU integrated vehicle attitude determination
Authors: Jiang Lei , Sun Rui , Cheng Qi , Yin Tong , Mao Yi
Published: October 2024

In land–based applications, the attitude of a vehicle can be accurately estimated by integrating data from global navigation satellite system (GNSS) and inertial measurement unit (IMU). However, traditional dual-antenna GNSS/IMU integrated systems are susceptible to signal reflection, diffraction, and interruption, leading to reduced accuracy and reliability in GNSS challenging environments. To address these issues, this study introduces an adaptive IMU error correction algorithm for dual-antenna GNSS/IMU integrated vehicle attitude determination. Initially, an IMU-aided baseline length constraint model is developed to enhance the ambiguity resolution performance of the integrated system in signal-degraded areas by incorporating precise prior information from the IMU. Furthermore, an adaptive IMU error correction mechanism based on long short-term memory and particle swarm optimization is proposed to predict the vehicle attitude during GNSS outages and to constrain the attitude error drift measured by lMU. Field test results demonstrate that, compared to two other candidate algorithms, the proposed algorithm improves accuracy in roll, pitch, and yaw by 19.23%, 30.56%, and 67.12%, respectively, and by 12.50%, 10.71%, and 38.39% respectively. Moreover, in two distinct scenarios where GNSS is blocked for 120 s, it was able to consistently deliver accurate and stable vehicle attitude information, maintaining roll, pitch, and yaw accuracy within 0.08 degrees.
Improving PPP timing and time transfer based on signal distortion biases calibration
Authors: Zang Minghui , Gong Xiaopeng , Chen Qusen , Gu Shengfeng , Guo Wenfei , Zhang Weixing
Published: October 2024

Precise point positioning (PPP) technology has been widely used for more than a decade in timing and time transfer. Pseudorange bias caused by signal distortion will reach up ±3 ns, which cannot be neglected in sub-nanosecond level PPP timing and time transfer. We propose to improve the performance of PPP timing and time transfer by considering signal distortion bias (SDB). In principle, SDB will affect PPP timing and time transfer by influencing the initial clock offset. Then, it is verified by theoretical and experimental analyses. The theoretical results show that the impact of SDB on PPP timing can reach up 1.8 ns in different regions. Also, the impact of SDB on time transfer can reach up 0.8 ns in different regions even if the baseline length and receiver types are the same. For experimental results, the accuracy of PPP timing and time transfer improves with SDB correction. For time transfer, the RMSs are reduced by 54.8%, 61.1% and 17.6% for GPS, BDS3 and Galileo in all links, respectively. The clock frequency consistency obtained from different systems has been improved. And the frequency stability of time link with Hydrogen clocks is improved by 53.0% at 10000s interval with SDB correction.
Evaluation of rotating components by combining individual classification with adaptive updating searching method in aero engine
Authors: Yang Runze , Huang Jingzhi , Lian Dongshan , Gao Shouru , Tonghan Lin , Zheng Yixuan , Liu Yongmeng , Tan Jiubin
Published: October 2024

In order to evaluate the roundness error of rotating components in aero engine with increased speed and more accurate estimation, this paper presents an enhanced method that integrates individual classification with adaptive updating searching (ICAUS) strategy. The individual classification method simulates the renewal regulations of various candidate points as iterations increase, subsequently generating new solutions for the next iteration. Additionally, an adaptive updating search zone method that varies in accordance with the increment of iterations is incorporated. These newly generated solutions are distributed within the updated search zone to ensure that the global optimal solution is not overlooked and the search zone is constrained to prevent excessive divergence, thereby enhancing computational efficiency. To validate the efficacy and accuracy of the proposed method, we utilized datasets and conducted comparative experiments using experimental methods previously studied by predecessors. The experimental results and comparisons demonstrate that the proposed ICAUS method exhibits superior convergence characteristics compared to previous studies. Across five distinct datasets, the average computation time satisfying the terminal conditions ranged from 0.0013 s to 0.0018 s, the standard deviation of the roundness was less than 6.2051 × 10–9 mm and the optimal solutions were obtained within 10–20 iterations, achieving the solution accuracy of ϵ= 10–8 mm.
Adaptive stochastic resonance enhanced weak linear frequency modulated signal perception in low signal-to-noise ratio environments
Authors: Liu Jin , Li Zan , Gao Yue , Miao Qiguang , Yang Li , Wang Danyang , Qi Peihan
Published: October 2024

The linear frequency modulated (LFM) signal has gained extensive utilization in radar, sonar and covert communication system due to its large time-bandwidth product, high-precision distance measurement and low detection probability. The perception of weak LMF signals holds significant importance yet encounters substantial challenges within the increasing complexity of the electromagnetic environments. Consequently, this paper proposes an adaptive stochastic resonance (ASR) enhanced approach for perceiving weak LFM signals in low signal-to-noise ratio (SNR) conditions. This approach initially commences a pioneering study on the quantitative synergistic resonance mechanism among LFM signals, random noise, and nonlinear stochastic resonance (SR) systems. Subsequently, the ASR system’s implementation becomes straightforward through the adaptive adjustment of SR system parameters according to the LFM signal and noise characteristics. This implementation leverages the inherent property of noise energy transfer to signal energy, facilitating the enhancement of ordered weak signals via random noise. Following the enhancement of the output signal by the ASR system, the Wigner–Ville distribution (WVD) transform’s time-frequency concentration property is employed to extract the time-frequency characteristics. Building on the WVD transform, the Radon transform with linear integral projection is applied to further harness the time-frequency domain energy concentration, thereby achieving the effective perception of weak LFM signals. Finally, the effectiveness of the proposed method in improving the perception performance of weak LFM signal in very low SNR conditions is verified through numerical simulations. It is anticipated that this method will have potential application value in fields such as radar, sonar, and communication under complex electromagnetic environments.
A proportional fusion adaptation algorithm to reduce noise in sEMG signals of the lower limb
Authors: Li Hao , Song Yongxian , Chen Quan , Li Yuanyuan , Zhang Qi
Published: October 2024

To address issues related to unknown noise pollution and the inadequate performance of single adaptive noise reduction algorithms in measuring lower limb surface electromyography (sEMG) signals, this paper proposes an algorithm that combines the fast convergence speed and strong noise reduction capability of recursive least-squares (RLS) with the low computational complexity of the normalized least-mean-square (NLMS) and improved proportionate NLMS (IPNLMS). Through the proportional fusion of RLS with NLMS and RLS with IPNLMS, the proposed algorithm greatly improves convergence speed, stability, and noise reduction performance while effectively reducing computational complexity. Moreover, considering the influence of the initial value of weights on the noise reduction performance during the updating process of the adaptive noise reduction algorithm, a weight initial value setting (WIS) module is proposed to optimize the initial value of the weights by the known amount of data. Based on 50 independent experiments, an adaptive noise reduction algorithm and WIS module were used to reduce the unknown noise in the lower limb sEMG signals, which was generated by white Gaussian noise, power line interference, or hybrid noise interfered by an unknown environment. The noise reduction performance was evaluated by using the average value of the signal-to-noise ratio (SNR), the root-mean-square error, and R-square. Compared with the RLS, NLMS, and IPNLMS algorithms for noise reduction of vastus lateralis, rectus femoris, and biceps femoris signals containing unknown noise, the SNR of RLS-NLMS, RLS-IPNLMS, WIS-RLS-NLMS, and WIS-RLS-IPNLMS is improved by an average of [7.92%, 55.54%, 55.63%], [7.45%, 54.90%, 54.99%], [19.70%, 72.38%, 72.71%], [19.32%, 71.84%, 72.19%]. The simulation results verify that the proportional fusion adaptive noise reduction algorithm and the WIS module effectively accelerate the convergence speed, enhance the noise reduction capability, and reduce the computational complexity.
Novel modified weights and cosine similarity based maximum marginal projection and its application in fault diagnosis
Authors: Wang Yongqiang , Wang Wei , Zhao Ruili , Chang Kaile , Duan Qixin
Published: October 2024

Facing the problem that the data generated in industrial processes have few labeled samples and the local manifold learning dimensionality reduction method ignores the local spatial structure of sample points and the distance relationship in constructing different weights. To solve the above problems, this paper presents a novel modified weights and cosine similarity based maximum marginal projection named MCMMP. In MCMMP, cosine similarity is used to consider the space feature of sample points, which enhances the performance of dimensionality reduction. The new modified weights are applied to measure the between-class and the within-class sample points, which enhance the divisibility of sample points. After MCMMP dimensionality reduction, the classifier is used to classify the dimensionality reduction sample points. Finally, the proposed new method is used in two cases Tennessee Eastman Process (TEP) and Three-phase Flow Facility (TFF) to test the fault diagnosis performance. The results of the simulation process indicated that the new fault diagnosis method based on MCMMP, compared with other related diagnosis methods, has good performance.
An aero–engine remaining useful life prediction model based on clustering analysis and the improved GRU–TCN
Authors: Chen Fudan , Yu Yang , Li Yuanjiang
Published: October 2024

Accurately predicting the remaining useful life (RUL) of engines is paramount for implementing effective preventive maintenance strategies, preventing injuries and fatalities caused by equipment failures, and significantly reducing routine repair and replacement costs. However, existing deep learning models often ignore the variable operating conditions in real engineering applications and do not sufficiently consider the interaction between time series and degradation laws, which directly leads to the inability to effectively extract to degradation feature extraction. To address this problem, this study developed a novel combined network model named CA–DRGRU–TTCN, aimed at accurately predicting the RUL of engines. Firstly, a density–based spatial clustering of applications with noise algorithm is used to identify multiple operating conditions, and incorporate the recognition results into the model as additional new features. The first degradation time point is determined by Jensen–Shannon divergence. Secondly, the deep connectivity of the residual gated recurrent unit (GRU) module is designed to extract deeper degradation features, and an improved time–based mean square error loss function based on the first degradation time point is applied to temporal convolutional networks (TCN) to better capture the dependency between the time series and the real degradation degree of the engine. Finally, experiment results on the C–MAPSS dataset show that the proposed method achieves better performance compared to existing state–of–the–art methods.
Doxorubicin-loaded methoxy-intercalated kaolinite as a repackaging of doxorubicin for an enhanced breast cancer treatment: in vitro and in vivo investigation
Authors: Sayed Fatma Al-Zahraa , Mohamed Ayman S , Fahmy Heba Mohamed
Published: October 2024

Doxorubicin (Dox) is one of the most common wide-spectrum chemotherapeutics. However, its efficacy is limited due to off-target accumulation and selectivity issues. In this study, we compared the anti-cancer effect and biocompatibility of KaoliniteMeOH-Dox (KMD), a Dox repackaging, to Dox monotherapy. The formulation was extensively tested using transmission electron microscopy, dynamic light scattering, zeta potential, Fourier transform infrared, x-ray diffraction, and in vitro drug release. The MTT assay measured MCF-7 cell growth inhibition in vitro. In vivo testing involved 20 naïve mice and 40 Ehrlich solid tumor-inoculated mice. The tumor size was monitored for 18 d. In all experimental groups, tumor and cardiac tissues were evaluated for cytotoxicity and genotoxicity by addressing oxidative stress, histopathology, and comet assay. We found that KMD has many advantages in terms of size, charge, shape, high loading efficiency (90.16%), and pH-dependent release. The MTT assay showed that the formulation outperformed Dox in growth inhibition and selectivity. In vivo, research showed that KMD suppressed tumors by 86.075% compared to 60.379% for free Dox. Histological analysis showed that KMD reduced tumor size, metastasis, and carcinogenic oxidative stress and inflammation in mice without harming naive mice. Based on the obtained data, the KMD formulation holds promise for breast cancer treatment and warrants further investigation.
The effect of intra- and inter-fractional motion on target coverage and margins in proton therapy for uveal melanoma
Authors: Björkman Daniel , Via Riccardo , Lomax Antony , De Prado Maria , Baroni Guido , Weber D C , Hrbacek Jan
Published: October 2024

Introduction. This study aims to assess the effective lateral margin requirements for target coverage in ocular proton therapy (OPT), considering the unique challenges posed by eye motion and hypofractionation. It specifically addresses the previously unaccounted-for uncertainty contribution of intra-fractional motion, in conjunction with setup uncertainties, on dosimetric determination of lateral margin requirements. Method. The methodology integrates dose calculations from the in-house developed treatment planning system OCULARIS with measured intra-fractional motion, patient models from EyePlan and Monte Carlo (MC) sampling of setup uncertainties. The study is conducted on 16 uveal melanoma patients previously treated in the OPTIS2 treatment room at the Paul Scherrer Institute (PSI). Result. The retrospective simulation analysis highlights a significant impact of non-systematic factors on lateral margin requirements in OPT. Simulations indicate that reducing the 2.5 mm clinical lateral margin, represented by a 2.1 mm margin in this work, would have resulted in inadequate target coverage for two patients, revealing a greater impact of non-systematic factors on lateral margin requirements. Conclusions. This work characterizes intra-fractional motion in 16 OPT patients and identifies limitations of clinical margin selection protocols for OPT applications. A novel framework was introduced to assess margin sufficiency for target coverage. The findings suggest that prior research underestimated non-systematic factors and overestimated systematic contributions to lateral margin components. This re-evaluation highlights the critical need to prioritize the management of non-systematic uncertainty contributions in OPT.
Investigation of optical soliton solutions for the cubic-quartic derivative nonlinear Schrödinger equation using advanced integration techniques
Authors: El-Horbaty Mahmoud , Gepreel Khaled A , Yildirim Yakup
Published: October 2024

This paper aims to investigate optical soliton solutions in the context of the cubic-quartic derivative nonlinear Schrödinger equation with differential group delay, incorporating perturbation terms for the first time. Motivated by the need to better understand soliton dynamics in advanced optical communication systems, we employ three integration techniques: the direct algebraic approach, Kudryashov’s method with an addendum, and the unified Riccati equation expansion method. Our study reveals that, by appropriately selecting parameter values, the resulting solutions include Jacobi elliptic functions that describe straddle solitons, bright, dark, and singular solitons. We also identify the conditions under which these soliton pulses can exist. Furthermore, we provide numerical simulations to illustrate these solutions under specific parameter settings, highlighting their potential applications in optical fiber systems.
Unlocking high-efficiency solar energy: optimizing P3HT/Si hybrid solar cells through numerical simulation
Authors: A K Sijo , Krishnan Akhil , Sapna P , Tom Emmanuel
Published: October 2024

This study numerically investigates the optimization of P3HT/Si hybrid solar cells for maximum efficiency via numerical simulation using SCAPS ID. The analysis identifies P3HT layer thickness and Si donor density as critical parameters, with optimal values of 20 nm and 1017 cm−3, respectively. Exceeding these values leads to decreased efficiency due to reduced hole mobility, increased recombination, and enhanced absorption loss. Furthermore, minimizing defect density in Si is crucial for achieving high efficiency. The optical properties of the P3HT/Si hybrid thin film were investigated using the transfer matrix method (TMM), yielding exceptional transmittance (94.5%), low reflectance (4.5%), and minimal absorption (1.0%) at a wavelength of 0.5876 μm. This highlights the material’s potential for efficient and transparent photovoltaic devices. By optimizing these parameters, a maximum efficiency of ∼24% was achieved, demonstrating the potential for high-performance hybrid solar cells. This work underscores the significance of numerical analysis in designing efficient hybrid solar cells, paving the way for the development of low-cost, high-performance devices via spin coating, a groundbreaking advancement in solar energy harvesting.
Monitoring kiloelectron-volt emission variability in partially observed nuclear events through distance weighted censored control charts
Authors: Nisar Shumaila , Raza Syed Muhammad Muslim , Albalawi Olayan , Alharthi Aiedh Mrisi , Mahmood Haider
Published: October 2024

The variation in the lifespan of particles is a crucial parameter in nuclear physics and is essential for identification purposes. Modern particle detectors excel at recognizing individual radioactive nuclei arrivals and their subsequent decay events. However, challenges arise when matching arrivals with departures, especially when departures are only partially observed. One inefficient approach involves conducting experiments with very low arrival rates to facilitate matching. The kiloelectron-volt E(keV) emission is obtained during this radio active process. This study focuses on the meticulous surveillance of the standard deviation in keV emission from partially observed events within the domain of nuclear physics.The utilization of censored control charts allows for the effective management of incomplete data, enabling researchers to make informed decisions despite potential limitations in observation. To accomplish this, the methodology employs the statistical approach known as Distance Weighted Mean based Standard Deviation (DWMS) integrated with the application of censored control charts. We propose a DWMS based exponentially weighted moving (DWMS-E) control chart for monitoring kiloelectron-volt E(keV) data. The proposed charts is developed for Weibull lifetimes with type-I censored data. The goal is to find changes in the mean of Weibull lifetimes with known and estimated parameter conditions. The performance of the proposed DWMS-E chart is evaluated by the average run length (ARL). Besides a simulation study, a real-life data set on E(keV) related to the alpha decays of 177 Lutetium isotope is also discussed.
Investigation of periodic heat transfer on the transient thermal characteristics of fully wet moving semi-spherical porous fin composed of functionally graded material
Authors: Pavan Kumar P L , Gireesha B J , Venkatesh P
Published: October 2024

This study investigates the thermal behaviour of a fully wet, moving semi-spherical porous fin made of linear Functionally Graded Material (FGM). This investigation examines the fin response to convective-radiative heat transfer under periodic variations in base temperature across three different FGM scenarios: Homogeneous material (HM), Functionally Graded Material I (FGM I) and Functionally Graded Material II (FGM II). The resultant nonlinear partial differential equation is accurately solved using the Finite Difference Method (FDM) and outcomes are benchmarked against existing literature. This research pioneers an investigation into the effects of periodic heat transfer on the detailed thermal profiles of FGM fin, an area not been explored in existing literature. It significantly enhances understanding of the influence of oscillatory base temperatures on thermal management within FGMs, uncovering pivotal insights into the interaction between material grading, amplitude of temperature oscillation and their collective effects on thermal efficiency. Additionally, this research assesses the influence of variables such as the amplitude of input temperature, frequency of oscillation, thermal conductivity grading parameter and others on temperature distribution along the fin length and over dimensionless time. Notably, periodic heat transfer induces a dynamically wavy thermal profile in the fin over time, attributable to oscillating base temperatures. Moreover, the analysis demonstrates that FGM II fin exhibit the most significant temperature distribution, followed by FGM I and HM. The fin heat transfer rate is profoundly influenced by the amplitude of input temperature and the thermal conductivity grading parameter. These insights are pivotal for optimizing fin designs in critical applications, including electronics cooling, HVAC systems, automotive engine cooling and solar energy collection, substantially improving upon traditional designs.
Non-linear dynamics and control of COVID-19 in india revisited : evidence of synergistic, antagonistic and threshold effects
Authors: Yogita  , Adlakha Neeru
Published: October 2024

Various researchers have investigated the COVID-19 pandemic dynamics since 2020 focusing on various aspects of the epidemics. However, the non-linear dynamics of this epidemic is still not well understood. India having the largest population in the world with wide cultural, genomics, and immunity diversity is being considered a suitable case for present investigation to generate the crucial information of non-linear phenomena during the first two waves of the epidemics. An SIRD model is suggested, integrating varying transmission, recovery, and mortality rates over time to explore the nonlinear behavior of the epidemic in India. The time-dependent transmission, recovery, and mortality are calculated using the finite difference method with the aid of actual data released by the Indian government, for the periods before and during the lockdown phases. The novel results generated from the model show evidence of synergistic, antagonistic, and threshold effects and the role of various measures in controlling these epidemic trends.