bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multistable dynamics and chaos in a system consisting of an inertial neuron coupled to a van der Pol oscillator
Authors: Tanekou Sosthene Tsamene , Kengne Jacques , Kenmoe Germaine Djuidje 
Published: October 2024

Abstract
We consider a dynamical system consisting of a van der Pol oscillator linearly coupled to an inertial neuron with two wells potential. Analytical studies are conducted focusing on the energy computation, the dissipation and symmetry, as well as the determination and characterization of the equilibrium points. We define the parameter ranges related to different types of oscillations in the coupled system in order to have an overall idea of the nature of the attractors (hidden or self-excited) that may exist. We apply numerical analysis techniques (2-parameter diagrams, bifurcation analysis, phase portraits, basins of attractions, etc) in accordance with the previous operating range in order to shed light on the plethora of competing dynamics of the model and possible forms of strange attractors as well. Another salient point of this work is the coexistence between five self-excited attractors (limit cycle and chaos) with a hidden attractor (limit cycle). We also examine the impact of symmetry breaking on the system response. An appropriate analog simulator of the coupled system is designed and simulated in PSpice in order to check the results reported during the theoretical analyses. We believe that the results of the present work complement and enrich previously published ones concerning the dynamics of a system composed of a van der pol oscillator coupled to a (non-oscillating) double-well oscillator.
Novel (3 + 1)-dimensional variable-coefficients Boussinesq-type equation: exploring integrability, Wronskian, and Grammian solutions
Authors: Madadi Majid , Asadi Esmaeel , Inc Mustafa 
Published: October 2024

Abstract
In this paper, we introduce a novel (3 + 1)-dimensional variable-coefficients Boussinesq-type equation. We analyze its integrability using the Painlevé test and the

N

-soliton solution, demonstrating that both tests yield identical conditions. Using the Hirota bilinear form of the equation, we derive Wronskian and Grammian determinant solutions utilizing Plücker relations and the Jacobi identity for determinants. In particular, we use elementary transformation and long wave limit to get the determinant expression of mth-order lump solutions from the 2mth-order Wronskian determinant solutions. Furthermore, we reveal a variety of novel semi-rational solutions using the Hirota method and Grammian determinant techniques.
Generation of dark pulses in mode-locked erbium-doped fiber ring laser using Ti2SnC absorber
Authors: Naidu Ruven Rhaj , Masruroh  , Diblawe Abdulkadir Mukhtar , Khudus Muhammad Imran M A , Harun Sulaiman Wadi 
Published: October 2024

Abstract
We report the experimental observation of domain-wall type dark solitons in an all-fiber ring cavity erbium-doped fiber laser (EDFL) mode-locked with a Titanium Tin Carbide (Ti2SnC) saturable absorber (SA). The SA, featuring a modulation depth of 8.2%, was created by incorporating Ti2SnC particles into a polyvinyl film. Dark pulse formation is attributed to cross-phase coupling resulting from cavity birefringence. The mode-locked laser operates at 1559 nm with pump power ranging from 30.9 mW to 90.0 mW, achieving a maximum pulse energy of 1.73 nJ, a repetition rate of 1.78 MHz, and a pulse width of 261.2 ns.
Advanced modelling techniques for magnetohydrodynamic Casson fluid squeezing flow via generalized fractional operators with neural network scheme
Authors: Rashid Saima , Tahir Madeeha , Asjad Muhammad Imran , Shafique Rafia , Alqurashi M S , Elagan S K 
Published: October 2024

Abstract
This paper aims to simulate and examine the unstable squeezed circulation of fractional-order (FO) magnetohydrodynamic (MHD) Casson fluid via a permeable medium. The Casson fluid system performs an essential role in comprehending the characteristics of non-Newtonian fluids, including toothpaste, condiments, printing substances and plasma circulation. The outcomes of this investigation are significant because previous research has not addressed the unsteady circulation of Casson fluid in a fractional nonsingular kernel and neural network-based stochastic context, considering the indicated consequences. An exceptionally dynamic ordinary differential equation is produced by using fractional calculus in combination with similarity transforms After that, the predicted problem is addressed employing an amalgam of the Laplace transform in the Caputo-Fabrizio, modified Atangana-Baleanu-Caputo fractional derivatives operators, and the q-homotopy analysis transform method, accompanied by no-slip boundary requirements. The responses and oversights at various points in the FOs are scrutinized, along with previous findings, in order to ensure reliability. In terms of precision, q-HATM findings outperform other outcomes that are accessible in research. The focus of this research is on the influence of FOs on the velocity distribution, skin friction coefficient (SFC) and practices of relevant fluid factors. To find out how relevant fluid components affect the velocity distribution and SFC, an extensive, qualitative and visual evaluation is carried out. It was discovered through evaluation that the FO shows an analogous impact for both positive and negative squeezing numbers. Additionally, as the FO increases, SFC reduces. Analysis revealed that the FO exhibits a similar effect with regard to positive and negative compression numbers. Furthermore, SFC decreases with increasing FOs. Additionally, a highly effective stochastic method employing artificial neural networks (ANNs) and a back-propagated Levenberg-Marquardt (BPLM) procedure is generated to explore the effect of different parameter modifications on the SFC, velocity distribution, as well as various fluid factors. Multiple effectiveness measures were developed according to mean absolute deviations (MAD), erroneous Nash-Sutcliffe effectiveness (ENSE), and Theil’s inequity coefficient (TIC) in order to verify the preciseness, productivity, and computing cost of the ANN-BPLM algorithms. The outlined scheme’s analytical findings are verified through comparison using numerical outcomes obtained through the q-HATM, artificial intelligence strategies like NARX-LM, and the least squares methodology (LSM). The outcomes indicate the resilience and accuracy of the layout procedure by demonstrating that the average percentage of errors in our proposed outcomes in terms of ENSE, TIC, and MAD is nearly zero.
Design of a CPW-based SSPP band-pass filter with reflectionless notch
Authors: Cao Yuan , Lu Yuming , Yin Songfeng , Lin Bin 
Published: October 2024

Abstract
This work proposes a band-pass filter (BPF) with a reflectionless notch based on spoof surface plasmon polaritons (SSPPs), utilizing interdigital coupling structures and novel transmission line unit cells. This filter efficiently transmits signals within the 0.67 GHz −4.06 GHz frequency range. By analyzing the equivalent LC circuit of the novel transmission line unit cell, its dispersion relation is derived using microwave network theory, with a cutoff frequency of 4.11 GHz. By comparing its dispersion relation with that of the conventional transmission line unit cell, the miniaturization capability of the proposed unit cell can be verified. In the BPF, loading a zigzag groove onto the central transmission line can be equivalently represented as an interdigital coupling structure, generating a stopband in the low-frequency range near 0 GHz. By deriving and analyzing its S-parameters, it is shown that the bandwidth of the low-frequency stopband can be flexibly adjusted by modifying the geometric dimensions of the zigzag groove. Additionally, loading another set of interdigital coupling structures onto the transmission line generates a notch at its resonant frequency of 3.4 GHz. It is noteworthy that in this configuration, the interdigital coupling structures along with the central transmission line can be represented equivalently as a set of CPW antennas. At the resonant frequency, the atructure radiates signals into free space, forming a reflectionless notch. Based on the simulations, a physical filter was fabricated and tested, showing excellent agreement between simulations and measurements.
Impact of metal deposition on the optical and interface properties of NiO: growth and characterization of NiO/metal thin bilayer films
Authors: Ghasemi Hasan , Mozaffari Mohammad Hazhir , Moradian Rostam 
Published: October 2024

Abstract
Since transparent conductive oxides (TCOs) provide electrical conductivity together with optical transparency, they have found wide applications in optoelectronic devices and photovoltaics. Among the TCOs, nickel oxide (NiO) is challenging due to its inherent trade-off between transparency and electrical conductivity. To address this challenge, one effective approach is to deposit a metal layer onto NiO thin films. In this work, NiO, NiO/Au, NiO/Ag, and NiO/Cu thin films are prepared by sputtering and thermal evaporation techniques on glass substrates and fully characterized finding the proper film for optoelectronic applications. The electrical and optical properties of the fabricated films are examined by four-point probe measurements and optical spectrometry. According to the obtained results, the NiO/Au, NiO/Ag, and NiO/Cu bilayers show sheet resistance of 200, 338, and 925 Ω sq−1 respectively while their optical bandgaps vary from 3.2 to 3.76 eV. These findings provide valuable insights into the performance of these films, making them potentially viable choices for various optoelectronic applications.
Analytical solutions and instability analysis of truncated M-fractional coupled dispersionless equations
Authors: Riaz H W A , Farooq Aamir 
Published: October 2024

Abstract
This paper comprehensively investigates the truncated M-fractional coupled dispersionless equations, a nonlinear system of partial differential equations characterized by its M-fractional derivative. The Jacobi elliptic function expansion method is employed to derive analytical solutions for the coupled system. In addition, the modulation instability of the solutions is thoroughly explored, providing a detailed exposition of the mathematical framework governing the system. The analytical solutions are graphically illustrated and analyzed to highlight their physical significance. These findings have significant applications in nonlinear optics, offering new insights into wave propagation and stability within such systems.
Testing gravity with frequency-dependent overlap reduction function in Pulsar Timing Array
Authors: Liang Qiuyue , Obata Ippei , Sasaki Misao 
Published: October 2024

Abstract
The positive evidence of a nano-hertz gravitational wave background recently found by several pulsar timing array (PTA) collaborations opened up a window to test modified gravity theories in a unique frequency band in parallel to other gravitational wave detection experiments.
In particular, the overlap reduction function (ORF) in PTA observation is sensitive to the phase velocity of gravitational waves.
In this work, we provide analytical expressions for the coefficients of the multipole moments in the ORF, and utilize these analytical results to study constraints on
the phase velocity from the frequency dependent overlap reduction function obtained from the Chinese PTA (CPTA) data.
While the data contain large error bars yet, interesting constraints are found in the frequency-dependent ORF in the case of subluminal phase velocity. This makes us expect that the nano-hertz band gravitational wave background will become one of the important arenas for exploring modified gravity theories.
Effects of primordial fluctuations on relic neutrino simulations
Authors: Zimmer Fabian , Abellán Guillermo Franco , Ando Shin'ichiro 
Published: October 2024

Abstract
After decoupling, relic neutrinos traverse the evolving gravitational imhomogeneities along their trajectories. Once they turn non-relativistic, this results in a significant amplification of the anisotropies in the cosmic neutrino background (CνB). Past studies have reconstructed the phase-space distribution of relic neutrinos from the local distribution of matter (accounting for the Milky Way halo and the surrounding large-scale structures), but have neglected the CνB anisotropies in the initial conditions of neutrino trajectories. Using our previously developed N-1-body simulation framework, we show that including these primordial fluctuations in the initial conditions can be important, as it produces similar effects on the abundance and anisotropies of the CνB as the inclusion of large-scale structures beyond the Milky Way halo. Interpretability of data from future CνB observatories like PTOLEMY therefore depends on correctly modelling these effects. GitHub: our jax-accelerated simulation code can be found here.
Near-Earth Asteroids as the Parents of the δ-Cancrid Meteoroid Stream
Authors: Kokhirova G. I. , Zhang M. , Li X. -G. , Zhonmuhammadi A. I. , Liu X. 
Published: October 2024

Abstract
The δ-Cancrid meteoroid stream forms four active meteor showers which are observable on the Earth annually during January–February and August–September. The stream’s definite parent comet has not been established. We performed a search for near-Earth asteroids (NEAs) associated with this stream. We have followed the backward evolution of the orbital elements of a sample of NEAs and found their orbits at the Earth-crossing positions. Using these orbits, we calculated the theoretical parameters of meteor showers associated with the considered NEAs. We carried out our search for observable active showers that match theoretically predicted ones with published data, and the result turned out that the predicted meteor showers of 13 NEAs were identified with the active showers produced by the δ-Cancrid meteoroid stream. The comet-like orbits of NEAs and established association with active meteor showers indicate their common cometary origin. The NEAs considered are moving within the stream and likely represent the dormant remnants of a parent comet of the δ-Cancrid asteroid-meteoroid complex that disintegrated more than 12 thousand years ago.
High-dimensional non-convex landscapes and gradient descent dynamics
Authors: Bonnaire Tony , Ghio Davide , Krishnamurthy Kamesh , Mignacco Francesca , Yamamura Atsushi , Biroli Giulio 
Published: October 2024

Abstract
In these lecture notes we present different methods and concepts developed in statistical physics to analyze gradient descent dynamics in high-dimensional non-convex landscapes. Our aim is to show how approaches developed in physics, mainly statistical physics of disordered systems, can be used to tackle open questions on high-dimensional dynamics in machine learning.
Development and tests of the 499.8 MHz srf cryomodules for HEPS
Authors: Zheng Hongjuan , Zhang Pei , Ma Qiang , Dai Jin , Han Ruixiong , Huang Tongming , Meng Fanbo , Mi Zhenghui , Lin Haiying , Wang Qunyao , Li Dongbing , Sun Liangrui , Sang Minjing , Zhao Tongxian , Jin Song , Ye Rui , Ge Rui , Zhao Facheng 
Published: October 2024

Abstract
A 499.8 MHz single-cell superconducting cavity has been
proposed as the active third-harmonic cavity for the High Energy
Photon Source (HEPS), a 6 GeV diffraction-limited synchrotron light
source currently under construction in Beijing. Two 499.8 MHz
cryomodules are required to provide a total of 3.5 MV of rf voltage
and 400 kW of beam power. A mechanically enhanced cavity design,
based on the original KEKB-type cavity, was developed to meet the
specifications of HEPS. Three cryomodules have been assembled and
subjected to horizontal tests. A comprehensive clean-assembly
procedure was developed, resulting in excellent rf performance
maintained from vertical tests to horizontal tests at cryogenic
temperatures. The unloaded quality factors of all three modules
exceeded 2.45×109 at 1.75 MV, significantly surpassing the
design goal. No field emissions were observed throughout the
tests. These are the highest-performing 500 MHz modules treated by
buffered chemical polishing, also outperforming the average
performance of their electropolished counterparts. Following
dedicated analyses and multiple road tests, one cryomodule was
successfully transported in its entirety from the test platform to
the HEPS tunnel, with well-controlled accelerations on delicate
components. Vacuum integrity and performance were well
maintained. The module has been accelerating electron beams since
August 2024 for the HEPS commissioning. This paper presents the
design, fabrication, assembly, cryogenic tests, and transportation
of the mechanically improved 499.8 MHz single-cell srf
cryomodule.
CSNS-II multi-harmonic LLRF upgrade and commissioning
Authors: Li Xiang , Wu Bin , Li Xiao , Wu Jian , Liu Yang , Zhang Chunlin , Long Wei , Zhu JunYu , Chen ShengYi , Liu Shenghua , Lu Zhijun 
Published: October 2024

Abstract
The second phase of the China Spallation Neutron Source
(CSNS-II) will employ a dual-harmonic RF system to mitigate the
significant space charge effects associated with 500 kW beam
power. To address this, three magnetic alloy loaded cavities,
characterized by their wideband and high-gradient properties, will
be integrated as multi-harmonic cavities in the upgrade
project. Additionally, the current LLRF control system hardware,
based on the CPCI platform, is encountering issues related to
discontinuation and performance limitations. This paper presents the
testing and verification of hardware upgrades and multi-harmonic
control system algorithms for the magnetic alloy loaded cavity LLRF
control system, ensuring the effective implementation of the
multi-harmonic control algorithm within the new hardware framework.
Experimental investigation of circumnutation-inspired penetration in sand
Authors: Anilkumar Riya , Martinez Alejandro 
Published: October 2024

Abstract
Probes that penetrate soil are used in fields such as geotechnical engineering, agriculture, and ecology to classify soils and characterize their properties in situ. Conventional tools such as the Cone Penetration Test (CPT) often face challenges due to the lack of reaction force needed to penetrate stiff or dense soil layers, necessitating the use of large drill rigs. This paper investigates more efficient means of penetrating soil by taking inspiration from a plant-root motion known as circumnutation. Experimental penetration tests on sands are performed with circumnutation-inspired (CI) probes that advance at a constant vertical velocity (

v

) while simultaneously rotating at a constant angular velocity (

ω

). These probes have bent tips with a given bent angle (

α

) and bent length (

L
1

). The variation of the mobilized vertical force (

F
z

), torque (

T
z

.), and the mechanical work components with the ratio of tangential to vertical velocity (ωR/ν, where R is the distance of the tip of the probe from the vertical axis of rotation) is investigated along with the effects of probe geometry, vertical velocity, and soil relative density (

D
R

). The results show that the soil penetration resistance does not vary with

v

, but it increases as

α

,

L
1

, and

D
R

are increased.

F
z

decays exponentially with increasing

ω
R

/

v

,

T
z

initially increases and then plateaus, while total work (

W
T

) shows little magnitude changes initially but later increases monotonically. The mechanisms leading to these trends are identified as the changes in the probe projected areas and mobilized normal stresses due to differences in probe geometry and the effects of

ω
R

/

v

on the resultant force direction and soil disturbance. The results show that CI penetration within a specific range of

ω
R

/

v

leads to small increases in

W
T

(i.e.,

⩽

25%), yet mobilizes

F
z

magnitudes that are 50%–80% lower than that mobilized during non-rotational penetration (i.e., CPT). This indicates that CI penetration can be adopted for in situ characterization or sensor placement with smaller vertical forces, allowing for use of lighter rigs.
Health benefits of decarbonization and clean air policies in Beijing and China
Authors: Kiesewetter Gregor , Zhang Shaohui , Liu Jun 
Published: October 2024

Abstract
Although China has seen strong reductions in air pollution levels in the last decade, PM2.5 concentrations still exceed the WHO Guideline several times, causing a substantial burden of mortality and morbidity. With many ‘low hanging fruits’ in terms of abatement measures already taken, further improvements will be more difficult and likely require different strategies than pursued so far. This study looks into the trends expected under current energy policies and air pollution control legislation and analyses the source contributions to ambient PM2.5 in China, with a special focus on the megacity of Beijing. Although reductions are foreseen, China appears not yet on track to meet its long-term targets for greenhouse gas emissions nor the future national air quality standards. Going beyond current policies, we analyze effects of measures which tackle both issues and quantify health co-benefits from further decarbonization policies required to meet the national target of reaching carbon neutrality by 2060, as well as the potential for further air pollution mitigation.
Puzzlingly low utilization of solar irrigation pumps by smallholders in Nepal undermines cost-effectiveness
Authors: Oziel Dan , Mukherji Aditi , Lamichhane Nabina , Fishman Ram 
Published: October 2024

Abstract
Solar powered irrigation pumps (SIP) hold substantial potential for low carbon irrigation expansion, particularly where affordable electricity is limited. In contrast to diesel-based irrigation, which carries steep fuel costs, irrigation by SIP requires zero marginal costs, but high initial investments. This makes their competitiveness with diesel pumps highly dependent on the temporal frequency of their usage. Using unique and detailed data on SIP usage by smallholders in Nepal, we show SIP usage frequency is low, making it financially competitive with diesel for only a small fraction of farmers. We analyze characteristics of farmers who make low/high usage of the SIP, and explore potential explanations for the puzzling low level of SIP use.