bluuebunny/crossref_metadata_2025 huggingface dataset:
Seventy-five years of vegetation change after fire in Tasmanian alpine heathland
Authors: Sorensen Ellen-Rose , Kirkpatrick Jamie B.
Published: May 2024

Context Alpine ecosystems are threatened by warming and an associated increase in fire frequency. There is a gap in our knowledge of succession in Tasmanian alpine heath more than 50 years after fire. The literature suggests that the alpine successional progression usually involves decreasing rates of change, decreasing differences among fire ages, ongoing transitions among shrub species, ongoing transitions from some lifeforms/species to others, and that warming results in increases in species richness. Aims We test for these tendencies up to 75 years from fire in alpine vegetation on kunanyi/Mount Wellington, Tasmania, Australia. Methods We documented the changes in vegetation structure and composition between 1998 and 2022 in plots on either side of an alpine fire boundary in the alpine heathland and used earlier data and observations to extend the record of change after fire to 75 years. We put these changes in the context of the only area of alpine vegetation that was not burnt in 1947 or later. Key results The area last burnt in 1947 exhibited declines in all lifeform covers between 1998 and 2022. All lifeforms except tall shrubs and mat shrubs declined in cover in the area last burnt in 1962. By 2022, shrub cover in the 1962-burnt area had not attained equivalence with the area last burnt in 1947. Herbs had the most dramatic decline in both fire-age classes. There were few shrub seedlings in 2022. All but six taxa, three being exotic, were observed in both the plots and previous broader surveys. Increases in species richness caused by the upward migration of lower-elevation species were not observed. The long-unburnt patch lacked the major dominant of the 1947-burnt plots, namely Orites acicularis, and was dominated by a gymnosperm absent from most of the mountain. Conclusions Succession follows the initial floristic composition model. The differences in trajectories from the 1947 and 1962 fires could possibly be due to desiccation or abrasion damage from increasing wind speeds and temperatures. There are strong indications of further potential change in the absence of fire. Implications The slow rate of recovery and its on-going nature emphasise the importance of keeping fire out of this vegetation type.
Spectroscopic measurement of atmospheric-pressure non-equilibrium Ar plasma using continuum and line spectra
Authors: Kikuchi Wataru , Yamashita Yuya , Nezu Atsushi , Akatsuka Hiroshi
Published: May 2024

A robust method for determining the electron temperature and density of atmospheric-pressure non-equilibrium argon plasmas is reported. The methodology is based on the analysis of the continuum and line spectra of the plasma. Assuming that the electron energy distribution function (EEDF) is expressed as a two-temperature generalized EEDF (GEEDF), the gamma value of the GEEDF is determined through a grid search of the continuum spectrum analysis given by the bremsstrahlung process, which minimizes the mean-squared logarithmic error (MSLE). In addition, the relationship between the gamma value and the electron temperature and density is determined. Utilizing this relationship, the electron temperature and density are determined by minimizing the MSLE between the excited-state densities obtained from the line spectrum analysis and numerically calculated using the collisional-radiative model. This methodology yielded results that satisfied both continuum and line spectrum analyses. In addition, the same analysis was conducted either by continuum spectrum analysis or by line spectrum alone to compare the results.
Analyzing the correlation between thermal and kinematic parameters in various multiplicity classes within 7 and 13 TeV pp collisions
Authors: Waqas Muhammad , Bietenholz Wolfgang , Bouzidi Mohamed , Ajaz Muhammad , Haj Ismail Abd Al Karim , Saidani Taoufik
Published: May 2024

We investigate the transverse momentum spectra of identified particles at 7 and 13 TeV in pp collisions in the framework of the blast wave model with Tsallis statistics (TBW). Based on experimental data by ALICE Collaboration, we observe that the model describes the p

T
spectra well with the common Tsallis temperature (T) and flow velocity (β

T
) but separate non-extensive parameters (q) for baryons and mesons. The parameter dependence on multiplicity as well as on collision energy is investigated, and a strong dependence on the former while a weak dependence on the latter is reported. The extracted parameters in this work consist of the initial temperature (T

i
), the average transverse momentum (〈p

T
〉), the Tsallis temperature (T), the flow velocity (β

T
), and the non-extensive parameter (q). These parameters are found to increase a little with increasing energy, however, they (except the parameter q) decrease significantly with decreasing multiplicity. We observe that β

T
drops to zero at high multiplicity , while, T and q do not change their behavior. Furthermore, our analysis explore the correlations among different parameters, including associations with the charged particle multiplicity per unit pseudorapidity (

〈
d

N
ch

/
d
η
〉

). The correlations between T and β

T
, T and

〈
d

N
ch

/
d
η
〉

, β

T
and

〈
d

N
ch

/
d
η
〉

, T

i
and 〈p

T
〉 and T

i
and

〈
d

N
ch

/
d
η
〉

demonstrates a positive relationship, while, the correlation between T and q − 1, and q − 1 and

〈
d

N
ch

/
d
η
〉

is negative. Finally, we implement an extra flow correction on the T parameter. Our findings reveal that the Doppler-corrected temperature parameter aligns closely with the T in scenarios with lower multiplicities. However, as the multiplicity increases, a noticeable divergence emerges between these parameters, indicating a widening separation between them.
Calibration and validation of a bleeding detector for beveled PMMA applicators in electron intraoperative radiotherapy
Authors: Garcia-Gil Rafael , Casans Silvia , Navarro-Antón A Edith , Martos Julio , Giompliaki Malamati , Pérez-Calatayud Ignacio , Sanchis Enrique , Pérez-Calatayud José , Sanchis-Sánchez Enrique
Published: May 2024

This study aimed to calibrate and validate a capacitive-sensor bleeding detector, originally designed for flat applicators, with beveled applicators (bPMMA), which are among the most commonly used applicators in intraoperative radiotherapy with electron mobile linacs. The detector will help prevent dose misadministration during irradiation in the event of fluid accumulation in the applicator, thus allowing for appropriate intervention. The handicap with employing this detector for bPMMA stems from the fact that the level of accumulated fluid depends on both the tilting angle and orientation of the applicator. Furthermore, the fluid remains accumulated at the bottom corner of the applicator, reducing the sensitivity of the sensor. A 5-strip capacitive sensor has been used, attached to a 4 cm diameter 30° beveled applicator with a tilting angle range from 0° to 30°. The sensor is read out using dedicated electronics, including a Wheatstone bridge circuit, amplifier, filter stages, and microcontroller. To calculate the sensitivity of the sensor, a prior calibration of the circuit has been carried out in order to obtain the relationship between the output voltage of the conditioning circuit and the height of the fluid present in the applicator for different inclinations. Using the average sensitivity over the inclination range of interest can provide accurate measurements of the estimated fluid height up to 12 mm, with a maximum deviation of approximately 2.0 mm and less than 1.0 mm for the 5 mm clinic threshold. The use of the mean sensitivity is a practical approach for detecting bleeding in beveled applicators because it simplifies the measurement process by avoiding the need to obtain detector sensitivity for each inclination and orientation of the applicator, which would be complex if not impractical in clinical use.
Comment on ‘Composition-based aluminum alloy selection using an artificial neural network’
Authors: Wanhill Russell
Published: May 2024

This article comments on the article ‘Composition-based aluminum alloy selection using an artificial neural network previously published in this journal. It is shown that the input information of the modelling is much too limited and the selection procedure is simplistic and not applicable or relevant to the actual selection procedures for aerospace aluminum alloys. The modelling has been done without sufficient engineering knowledge (almost none) about the properties, selection criteria, alloy compositions and processing of aerospace structural aluminum alloys.
Characterization of selected additive manufacturing materials for synchrotron monochromatic imaging and broad-beam radiotherapy at the Australian synchrotron-imaging and medical beamline
Authors: Bustillo John Paul O , Paino Jason , Barnes Micah , Cameron Matthew , Rosenfeld Anatoly B , Lerch Michael L F
Published: May 2024

Objective. This study aims to characterize radiological properties of selected additive manufacturing (AM) materials utilizing both material extrusion and vat photopolymerization technologies. Monochromatic synchrotron x-ray images and synchrotron treatment beam dosimetry were acquired at the hutch 3B and 2B of the Australian Synchrotron-Imaging and Medical Beamline. Approach. Eight energies from 30 keV up to 65 keV were used to acquire the attenuation coefficients of the AM materials. Comparison of theoretical, and experimental attenuation data of AM materials and standard solid water for MV linac was performed. Broad-beam dosimetry experiment through attenuated dose measurement and a Geant4 Monte Carlo simulation were done for the studied materials to investigate its attenuation properties specific for a 4 tesla wiggler field with varying synchrotron radiation beam qualities. Main results. Polylactic acid (PLA) plus matches attenuation coefficients of both soft tissue and brain tissue, while acrylonitrile butadiene styrene, Acrylonitrile styrene acrylate, and Draft resin have close equivalence to adipose tissue. Lastly, PLA, co-polyester plus, thermoplastic polyurethane, and White resins are promising substitute materials for breast tissue. For broad-beam experiment and simulation, many of the studied materials were able to simulate RMI457 Solid Water and bolus within ±10% for the three synchrotron beam qualities. These results are useful in fabricating phantoms for synchrotron and other related medical radiation applications such as orthovoltage treatments. Significance and conclusion. These 3D printing materials were studied as potential substitutes for selected tissues such as breast tissue, adipose tissue, soft-tissue, and brain tissue useful in fabricating 3D printed phantoms for synchrotron imaging, therapy, and orthovoltage applications. Fabricating customizable heterogeneous anthropomorphic phantoms (e.g. breast, head, thorax) and pre-clinical animal phantoms (e.g. rodents, canine) for synchrotron imaging and radiotherapy using AM can be done based on the results of this study.
Cooperative states and shift in resonant scattering of an atomic ensemble
Authors: Hsu Ting , Lin Kuan-Ting , Lin Guin-Dar
Published: May 2024

We investigate the spectral shift known as the collective Lamb shift in forward scattering for a cold dense atomic cloud. The shift results from resonant dipole–dipole interaction mediated by real and virtual photon exchange, forming many-body states displaying various super- and subradiant behaviour. However, the scattering spectrum reflects the overall contributions from these states but also averages out the radiative details associated with the underlying spin orders, causing ambiguity in determination and raising controversy on the scaling property of this shift. We employ a Monte–Carlo simulation to study how the collective states contribute to emission. We thus distinguish two kinds of collective shift that follow different scaling laws. One results from dominant occupation of the near-resonant collective states. This shift is usually small and insensitive to the density or the number of participating atoms. The other comes from large spatial correlation of dipoles, associated with the states of higher degree of emission. This corresponds to larger collective shift that is approximately linearly dependent on the optical depth. We further demonstrate that the spatial spin order plays an essential role in superradiant emission. Our analysis provides a novel perspective for understanding collective scattering and cooperative effects.
Rotational disturbance in laser-interferometric gravity gradiometry
Authors: Shiomi Sachie
Published: May 2024

Laser interferometers have been used for precise measurements of gravity and related effects. These include experiments to search for a fifth force and absolute ballistic gravimeters, which use a Michelson-type laser interferometer to measure the acceleration of a free-falling test mass. In these methods of instrumentation, the motion of free-falling test masses is measured using corner-cube laser interferometers, in which at least one retroreflector is embedded in each test mass. However carefully each of such test masses is released into free fall, a small amount of rotation is unavoidable which changes the optical path length and causes acceleration disturbance. This rotational disturbance could ultimately limit the measurement sensitivity of the laser interferometers. Various experimental and theoretical studies have been conducted to minimise the rotational disturbance in absolute ballistic gravimeters. This paper focuses on the rotational disturbance in laser-interferometric gravity gradiometers (LIGGs) that measure differential acceleration between two test masses freely falling at different heights in a vacuum. LIGGs can be configured to measure not only vertical gravity gradients, but also horizontal gradients, or gradients in both horizontal and vertical directions. However, only those to measure vertical gravity gradients have been constructed so far. Hence, in this paper, the term LIGGs specifically indicates the gravity gradiometers that measure vertical gravity gradients. Unlike absolute ballistic gravimeters, the LIGGs are, in principle, insensitive to ground vibrations; they can potentially detect some effects that are buried in seismic noise in absolute gravity data. To fully leverage this advantage of the LIGGs, it is crucial to keep the rotational disturbance to a minimum. Expressions for the rotational disturbance are derived and its magnitude is estimated based on available experimental data. The results show that the magnitude would not be more than 0.1

μ
Gal

/m in the measurement of vertical gravity gradients in a compact LIGG. Alternative designs and requirements for increasing the sensitivity of the LIGGs are also discussed.
Modulating spin current induced effective damping in β–W/Py heterostructures by a systematic variation in resistivity of the sputtered deposited β–W films
Authors: Aon Soumik , Pal Sayani , Manna Subhadip , Mitra Chiranjib , Mitra Partha
Published: May 2024

Utilizing the spin-induced pumping from a ferromagnet (FM) into a heavy metal (HM) under the ferromagnetic resonance (FMR) condition, we report an enhancement in effective damping in β- W/Py bilayers by systematically varying resistivity (ρ

W
) of β-W films. Different resistivity ranging from 100 μΩ-cm to 1400 μΩ-cm with a thickness of 8 nm can be achieved by varying the argon pressure (P

Ar
) during the growth by the method of sputtering. The coefficient of effective damping α

eff
is observed to increase from 0.010 to 0.025 with ρ

W
, which can be modulated by P

Ar
. We observe a modest dependence of α

eff
on the sputtering power (p

S
) while keeping the P

Ar
constant. α

eff
dependence on both P

Ar
and p

S
suggests that there exists a strong correlation between α

eff
and ρ

W
. It is thus possible to utilize ρ

W
as a tuning parameter to regulate the α

eff
, which can be advantageous for faster magnetization dynamics switching. The thickness dependence study of Py in the aforementioned bilayers manifests a higher spin mixing conductance (

g

eff

↑
↓

) which suggests a strong spin pumping from Py into the β-W layer. The effective spin current (J

S(eff)) is also evaluated by considering the spin-back flow in this process. Intrinsic spin mixing conductance (

g

W

↑
↓

) and spin diffusion length (λ

SD
) of β-W are additionally investigated using thickness variations in β-W. Furthermore, the low-temperature study in β-W/Py reveals an intriguing temperature dependence in α

eff
which is quite different from α

b
of single Py layer and the enhancement in α

eff
at low temperature can be attributed to the spin-induced pumping from Py layer into β-W.
Anisotropic stellar structures admitting Karmakar condition in f(R, φ, χ) theory
Authors: Sharif M , Gul Muhammad Zeeshan
Published: May 2024

This article employs the Karmarkar condition to study the geometry of compact stars experiencing anisotropy in the context of f(R, φ, χ) gravity. The unknown constants involved in Karmarkar condition are calculated by matching the internal and external regimes at the hypersurface. We investigate the acceptable behavior of matter variables and anisotropy. The viability of all the resulting models is checked using energy bounds. We also discuss some important factors such as mass, compactness and redshift parameters. Finally, we investigate the stable aspect of considered stars through causality condition and Herrera cracking technique. We conclude that all the discussed stellar structures in this theory satisfy the required constraints.
Structural properties controlled magnetisation of Ni/Al multilayers sputtered on flexible polymer substrate: Impact of Ni deposition rates
Authors: Kaplan Nadir , Karpuz Ali , Köçkar Hakan
Published: May 2024

The goal of this work is to determine how the rate of Ni deposition rates affect the structural characteristics that regulate the magnetization of Ni/Al multilayer thin films sputtered on flexible acrylic acetate polymer substrates. The films with a 5[Ni(20 nm)/Al(10 nm)] structure were gradually sputtered as different Ni deposition rates in the total thickness of 150 nm. With an increase in the rate of Ni deposition, the Ni contents increased from 61.5% to 69.6%. And, X-ray diffraction analysis verified that the films featured a face-centered cubic structure with variable peak intensities. Also, the scanning electron microscopy surface morphology analyses revealed that variations in the film surfaces were a result of the deposition rates. For magnetic measurements, the differences in the structural analysis were observed to cause a notable variation in saturation magnetization, MS, and coercivity, HC values. Accordingly, MS values increased consistently between 359.0 and 389.7 emu cm−3, but HC values decreased from around 34–32 to 28 Oe with the increase in Ni deposition rate from 0.02 to 0.10 nm s−1. It is also observed that when the Ni layers are generated at very fast deposition rates, the Ni/Al multilayer films have a high MS/HC ratio, which is significant for magnetic sensors. It has been concluded that the magnetisation of Ni/Al multilayer thin films can be controlled by the structural properties adjusting the Ni deposition rate.
Processing of shape memory alloys research, applications and opportunities: a review
Authors: Mehta Amrinder , Singh Gurbhej , Vasudev Hitesh
Published: May 2024

Shape Memory Alloys (SMAs) are metallic materials with unique thermomechanical characteristics that can regain their original shape after deformation. SMAs have been used in a range of industries. These include consumer electronics, touch devices, automobile parts, aircraft parts, and biomedical equipment. In this work, we define the current state of the art in SMA manufacturing and distribution across the aerospace, healthcare, and aerospace industries. We examine the effect of manganese on the structure and mechanical and corrosive properties of SMA Cu-Al-Ni and discuss the importance of incorporating small and medium-sized enterprises in the study of cu-Al luminum. This research outlines a fundamental example of SME integration in the analysis of superelasticity, a critical instance of SMA activity. It can also serve as a reference for activities such as medical, aerospace, and other industries that target SMA-based equipment and systems. Also, they can be used to look at SMA activation and material upgrade mechanisms. These FEM simulations are advantageous in optimizing and promoting design in fields such as aerospace and healthcare. FEM simulations identify the stress and strength of SMA-based devices and structures. This would result in minimizing cost and usage and lowering the risk of damage. FEM simulations can also recognize the weaknesses of the SMA designs and suggest improvements or adjustments to SMA-based designs.
Effect of calcination temperature on structure evolution of hematite nanoparticles
Authors: Husain H , Adi W A , Subaer S , Taryana Y , Setiawan A , Putri S E , Klyusubun W , Wannapaiboon S
Published: May 2024

The objective of this study is to investigate the transition structure of iron oxide, specifically the change from magnetite to hematite, as well as the influence of calcination temperature on the structural growth of hematite nanoparticles. The magnetite was extracted from the native iron sand in Indonesia using the coprecipitation procedure. To generate hematite, magnetite was calcined at various temperatures (350, 500, 650, and 800 °C). The structural changes resulting from the effect of calcination temperature were investigated by combining a number of characterisation methods. The crystal structure was examined using synchrotron x-ray diffraction (SRD) and the local structure was examined using x-ray absorption spectroscopy (XAS). Crystallite size was calculated using the Debye-Schrerrer equation at the most dominant SRD peak. Surface morphology was investigated using scanning electron microscopy (SEM). SRD data revealed that the sample calcined at 350 °C displayed both the Fe3O4 and α-Fe2O3 phases, while higher temperatures revealed the single-phase α-Fe2O3. Furthermore, an increase in calcination temperature was shown to be associated with an increase in crystallinity and crystallite size. For the samples H350 and H800, the crystallinity increased from 95.56 to 98.17%. In the magnetite, H350, H500, H650, and H800 samples, the crystallite size increased from 9.57 to 29.55, 16.40, 28,48, 29.26, and 29.55 nm. Higher calcination temperatures, on the other hand, increase the interatomic distance while decreasing the Debye–Waller factor, according to XAS fitting data. It can be inferred that around 500 °C, the transition from Fe3O4 to single-phase α-Fe2O3 was observed. While a greater calcination temperature of at least 800 °C would alter the structural parameters, it would not affect the phase.
n-Lüders channels: a novel class of rebit channels, their properties and applications
Authors: Berthier Michel , Provenzi Edoardo
Published: May 2024

In a very recent paper, the complete classification of rebit channels has been achieved. Here, we exploit that result to show how the classification can be used to perform an exhaustive analysis of a novel class of rebit channels induced by effects called n-Lüders channels. In the final part of the paper we propose a concrete application of these channels within the mathematical framework of a quantum theory of color perception that originated the interest about a rebit channels classification.
QCA-based fault-tolerant XOR Gate for reliable computing with high thermal stability
Authors: Naz Syed Farah , Shah Ambika Prasad , Ahmed Suhaib
Published: May 2024

The XOR gate is an essential element in the design of digital circuits due to its versatility and usefulness. The design of XOR gate in this paper is based on Quantum-dot Cellular Automata (QCA) 2D planner technology with no line-to-line intersections. The output amplitude is improved by redundant cell-based design, which also helped reliability and fault tolerance outperform. The proposed XOR gate achieves fault tolerance to single-cell addition and missing-cell defects from 68.48% to 95.33%. In addition, the proposed XOR gate is also fault-tolerant against multiple-cell missing defects, as verified from the simulations. Furthermore, high thermal stability makes the circuit reliable for QCA-based digital design applications. The digital design applications such as 4-bit B2G code converter and a 4-bit parity checker are designed from this XOR gate, utilizing 438 and 414 cells, respectively. This demonstrates its effectiveness in designing fault resilient and reliable circuit designs for various applications.
Anatomy of astrophysical echoes from axion dark matter
Authors: Todarello Elisa , Calore Francesca , Regis Marco
Published: May 2024

If the dark matter in the Universe is made of μeV axion-like particles (ALPs), then a rich phenomenology can emerge in connection to their stimulated decay into two photons. We discuss the ALP stimulated decay induced by electromagnetic radiation from Galactic radio sources. Three signatures, made by two echoes and one collinear emission, are associated with the decay, and can be simultaneously detected, offering a unique opportunity for a clear ALP identification. We derive the formalism associated with such signatures starting from first principles, and providing the relevant equations to be applied to study the ALP phenomenology.
We then focus on the case of Galactic pulsars as stimulating sources and derive forecasts for future observations, which will be complementary to helioscopes and haloscopes results.
The price of abandoning dark matter is nonlocality
Authors: Deffayet C. , Woodard R.P.
Published: May 2024

We consider the classic question posed by Pardo and Spergel about the
price of abandoning dark matter in the context of an invariant,
metric-based theory of gravity. Our answer is that the price is
nonlocality. This has been known for some time in the context of the
quasi-static regime. We show that it also applies for cosmology and
we exhibit a model which reproduces standard CDM successes such as
perturbations in the cosmic microwave background, baryon acoustic
oscillations and structure formation.
Unifying inflationary and reheating solution
Authors: Kaur Manjeet , Nandi Debottam , B Sharath Raghavan
Published: May 2024

The conventional background solution for the evolution of a single canonical inflaton
field performs admirably in extreme scenarios such as the slow-roll phase (where the slow-roll
parameter is much less than one) and the deep reheating era (where the Hubble parameter is much
smaller than the effective mass of the potential and the field oscillates around the minimum of
the potential), but fails to accurately depict the dynamics of the Universe around the end of
inflation and the initial oscillatory phases. This article proposes a single, unified,
model-independent, parametrized analytical solution for such models that bridges the gap between
these two extremes, providing a near-accurate comprehensive description of the evolution of the
Universe. This novel strategy has the potential to substantially enhance both quantitative and
qualitative cosmological observational predictions, and, as a consequence, can further constrain
the inflationary models more effectively using future observations.
Loop contributions to the scalar power spectrum due to quartic order action in ultra slow roll inflation
Authors: Maity Suvashis , Ragavendra H.V. , Sethi Shiv K. , Sriramkumar L.
Published: May 2024

The investigation of the theory of inflation beyond the linear
order in perturbations is important both for theoretical consistency and
potential observables.
In the contemporary literature, the calculation of modifications to the
inflationary scalar power spectrum due to the loops from the higher order
interaction terms in the Hamiltonian have led to an interesting discussion
regarding the validity of perturbation theory and the robustness of its
predictions.
Recently, there have been many efforts to examine the contributions to the
scalar power spectrum due to the loops arising from the cubic order terms
in the action describing the perturbations, specifically in inflationary
scenarios that permit an epoch of ultra slow roll (USR).
A brief phase of USR during inflation is known to lead to interesting features
in the scalar power spectrum which in turn has significant observational
consequences, such as the copious production of primordial black holes.
In this work, we consider the loop contributions to the scalar power spectrum
in a scenario of USR inflation arising due to the quartic order terms
in the action describing the scalar perturbations.
We compute the loop contributions to the scalar power spectrum due to the
dominant term in the action at the quartic order in a scenario wherein a
short phase of USR is sandwiched between two stages of slow roll (SR) inflation.
We analyze the behaviour of the loop contributions in terms of the parameters
that characterize the non-trivial inflationary dynamics, viz. the onset and
duration of USR, and the smoothness of transitions between the USR and SR phases.
We examine three different cases of the scenario — the late, intermediate and
early epochs of USR during inflation, each of which affects the scalar power
spectrum over different ranges of wave numbers.
In the inflationary scenario involving a late phase of USR, for reasonable choices
of the parameters, we show that the loop corrections are negligible for the entire
range of wave numbers.
In the intermediate case, the contributions from the loops prove to be scale
invariant over large scales and, we find that these contributions can amount
to 30% of the leading order (i.e. the Gaussian) power spectrum.
In the case wherein USR sets in early, we find that the loop contributions could
be negative and can dominate the power spectrum at the leading order, which
indicates a breakdown of the validity of the perturbative expansion.
We discuss the origin of the negative sign and the divergences that arise in the
loop contributions to the power spectrum.
We conclude with a brief summary and outlook.
Image ciphertexts classification method based on ghost imaging and intraclass-interclass difference
Authors: Zhao Dan , Li Yue , Zhang Jialin , Liu Yang , Sun Mingze , Li Xinjia , Yu Zhan , Li Ying , Yuan Sheng , Zhou Xin
Published: May 2024

In this paper, based on ghost imaging encryption, the preservation of Manhattan distance feature in ciphertext compared with plaintext is analyzed by utilizing the intraclass-interclass difference of image classification, and a classification method for image ciphertexts is proposed. After calculating Manhattan distance for both plaintexts and ciphertexts, respectively, the intraclass-interclass difference can be determined. The image that minimizes the intraclass-interclass difference is taken as the centroid to verify the consistency of the classification for various plaintext-ciphertext pairs under the same operation. The feasibility of proposed method is verified by numerical simulations, that the values of ACC and Weighted-F2 can be up to 90% when the MNIST is adopted as the test dataset. The whole process can be regarded as a kind of classification process by homomorphic encryption, however, different from the traditional homomorphic encryption methods based on mathematical model, the proposed method is accomplished based on the optical theory, and it does not require a lot of pre-training through models such as deep learning and neural networks, that means, reducing the computational expenses.
Inclusive quasielastic neutrino-nucleus scattering with energy density functional nuclear models*
Authors: Kim K. S. , Choi Soonchul , Gil Hana , Hyun Chang Ho
Published: May 2024

In this study, we calculated the inclusive charged-current neutrino-nucleus scattering from 40Ar in the quasielastic region. To explore the effect of uncertainties stemming from the nuclear structure, we used the KIDS (Korea-IBS-Daegu-SKKU) nuclear energy density functional and Skyrme force models, namely SLy4, SkI3, and MSk7. These models were selected to have distinct behavior in terms of the density dependence of the symmetry energy and the effective mass of the nucleon. In the charged-current neutrino scattering, the single- and double-differential cross sections were calculated for various kinematics. Total cross sections are reported as a function of the incident neutrino energy. The theoretical cross sections were compared with experimental data, and the roles of the effective mass and symmetry energy were investigated in terms of charged-current neutrino-nucleus scattering.
Calculation of the energy dependence of fission fragments yields and kinetic energy distributions for neutron-induced 235U fission*
Authors: Han 韩 Ya-Ning 亚宁 , Wei 韦 Zheng 峥 , Wang 王 Yi-Xuan 艺璇 , Huo 霍 Dong-Ying 东英 , Zhang 张 Peng-Qi 鹏琦 , Li 李 Ming 明 , Ma 马 Jun 骏 , Wu 吴 Kang 康 , Zheng 郑 Yong-Guang 永光 , He 何 Yuan 源 , Deng 邓 Zhi-Yong 志勇 , Jiang 蒋 Tian-Zhi 天植 , Zhuo 卓 Xiang-Lin 祥林 , Li 李 Jin 进 , Zhang 张 Yun 芸 , Zhang 张 Yu 宇 , Wang 王 Jun-Run 俊润 , Su 苏 Xiao-Dong 小东 , Yao 姚 Ze-En 泽恩
Published: May 2024

Fission fragments yields and average total kinetic energy are fundamental nuclear data for nuclear energy applications and the study of nuclear devices. Certain fission products, such as 95Zr, 99Mo, 140Ba, 144Ce, and 147Nd, serve as burnup monitors, assessing the number of fissions induced by neutrons on 235U. However, current experimental data for these fission products worldwide are inconsistent, introducing significant uncertainty into related scientific research. In this study, we employed the Potential-driving Model to calculate the independent yields of 235U and evaluate its advantages in such calculations. Additionally, we investigated the energy dependence of independent yields to select important products. Furthermore, we calculated the cumulative yields of 95Zr, 99Mo, 140Ba, 144Ce, and 147Nd, and compared them with existing literature data to explore the energy dependence of fission products for 235U. Given the lack of fission product yield data above 14.8 MeV, we extended our calculated incident neutron energy to 20 MeV, aiming to support future scientific research. The Geant4 physical model does not consider the influence of incident neutron energy on the average total kinetic energy of fission fragments; thus, we introduced the excitation function of the total kinetic energy of fission fragments recommended by Madland et al., which effectively describes the experimental data of the average total kinetic energy of fragments formed in 235U fission. In this paper, we comprehensively discuss the energy dependence of fission product yields and average total kinetic energy.
Reinforcement learning for closed-loop regulation of cardiovascular system with vagus nerve stimulation: a computational study
Authors: Sarikhani Parisa , Hsu Hao-Lun , Zeydabadinezhad Mahmoud , Yao Yuyu , Kothare Mayuresh , Mahmoudi Babak
Published: May 2024

Objective. Vagus nerve stimulation (VNS) is being investigated as a potential therapy for cardiovascular diseases including heart failure, cardiac arrhythmia, and hypertension. The lack of a systematic approach for controlling and tuning the VNS parameters poses a significant challenge. Closed-loop VNS strategies combined with artificial intelligence (AI) approaches offer a framework for systematically learning and adapting the optimal stimulation parameters. In this study, we presented an interactive AI framework using reinforcement learning (RL) for automated data-driven design of closed-loop VNS control systems in a computational study. Approach. Multiple simulation environments with a standard application programming interface were developed to facilitate the design and evaluation of the automated data-driven closed-loop VNS control systems. These environments simulate the hemodynamic response to multi-location VNS using biophysics-based computational models of healthy and hypertensive rat cardiovascular systems in resting and exercise states. We designed and implemented the RL-based closed-loop VNS control frameworks in the context of controlling the heart rate and the mean arterial pressure for a set point tracking task. Our experimental design included two approaches; a general policy using deep RL algorithms and a sample-efficient adaptive policy using probabilistic inference for learning and control. Main results. Our simulation results demonstrated the capabilities of the closed-loop RL-based approaches to learn optimal VNS control policies and to adapt to variations in the target set points and the underlying dynamics of the cardiovascular system. Our findings highlighted the trade-off between sample-efficiency and generalizability, providing insights for proper algorithm selection. Finally, we demonstrated that transfer learning improves the sample efficiency of deep RL algorithms allowing the development of more efficient and personalized closed-loop VNS systems. Significance. We demonstrated the capability of RL-based closed-loop VNS systems. Our approach provided a systematic adaptable framework for learning control strategies without requiring prior knowledge about the underlying dynamics.
Evolution of hydrogen isotopes retention behavior of in-situ boronization films in EAST
Authors: Puyang S.A. , Xu Y.P. , Guan Y.H. , Yang Z.S. , Ding F. , Zhou H.S. , Zuo G.Z. , Hu J.S , Luo G.-N. ,   the EAST Team
Published: May 2024

Effective management of hydrogen isotopes retention in plasma-facing materials (PFMs) is crucial, particularly when utilizing tritium (T) as fuel, for the success of burning plasma operations. Boronization, a widely employed technique for controlling fuel recycling and mitigating impurity influx from plasma-surface interactions into the core of burning plasma, significantly influences hydrogen isotopes retention in PFMs. In this study, boronization films were generated by ion cyclotron range of frequency (ICRF) discharge assisted boronization with C2B10H12 as boron source on tungsten substrates at Experimental Advanced Superconducting Tokamak (EAST) which employing ITER-like water-cooled W monoblock PFMs and components (PFCs), followed by in-situ glow discharge (GD) cleaning for 2 h and 20 shots (180 s) edge-plasma exposure. Employing the Material and Plasma Evaluation System (MAPES), representative samples were analyzed after each process. The resultant carbon–boron films, dense and continuous, exhibited thickness up to 120 nm and were identified as amorphous in structure. It was observed that the D2-GD cleaning resulted in a significant isotopic exchange effect, effectively reducing the hydrogen (H) retention in the carbon–boron films. This hydrogen isotope replacement efficiency was found to be influenced by the thickness of the films. Notably, after boundary plasma exposure, samples with thicker films demonstrated an enhanced capacity to capture deuterium (D), adsorbing 10 times more D than bare tungsten (W). Our findings offer transformative insights for T recycling analysis and the plasma operation of devices like International Thermonuclear Experimental Reactor (ITER), highlighting the impact of boronization and subsequent treatments on hydrogen isotope retention behavior in PFMs.
Matrix Inverse Problemunder the Central Master Submatrix Constraint AX = B of the Generalized Centersymmetric Solution
Authors: Wang Wen , Aishanjiang Muyesaier , Han Xiying
Published: May 2024

This paper begins by identifying a problem related to the solvability of the matrix equation AX=B, particularly within the realm of generalized centrosymmetric matrices. It exploits the distinctive properties inherent in generalized centrosymmetric matrices, primary focus involves investigating their solutions within the context of the matrix equation AX=B. This paper establishes the necessary and sufficient conditions for solvability while formulating a comprehensive expression for the generalized centrosymmetric solution. Furthermore, the paper delves into addressing the associated optimal approximation quandary concerning a specified matrix within the solution set.
On the Computation of Floquet Multipliers for Periodic Solution in Piecewise-smooth Dynamical System
Authors: Lai Cheng , Chen Yanmao
Published: May 2024

The floquet multiplier is one of the most important indicators for the stability and bifurcation analysis for periodic solutions in nonlinear dynamical systems. Different from the well-established Floquet theory for the perturbation systems of smooth systems, much less has been understood in its counterpart for non-smooth systems. Here in this paper, we will report an unusual and interesting feature of the Floquet multipliers for piecewise-smooth dynamical systems. When the initial condition of the periodic solution is located at the boundary splitting the solution domain, the multipliers would be calculated falsely in certain circumstances, respectively, by a saltation matrix method or a direct numerical integration for the perturbation system. We elucidate the origin of the fake multipliers through perturbation analysis, and furthermore suggest an effective manner to avoid the miscalculation. This finding would be of fundamental significance to both the real-world applications and theory establishment of the Floquet theory in non-smooth systems
Multi-objective Evolutionary Algorithm with Variable Neighborhood Search for Optimizing Green Scheduling in a Re-Entrant Hybrid Flow Shop with Dynamic Events
Authors: Tong Shuiguang , Yan Xiaoyan , Tong Zheming , Wu Xiuli , Jin Xiaofeng
Published: May 2024

In previous studies on re-entrant hybrid flow shops, the impact of dynamic events was often ignored despite being a common occurrence in practical production. To address this issue and simultaneously reduce energy consumption, a multi-objective evolutionary algorithm with variable neighborhood search (MOEA-VNS) has been proposed to optimize the green scheduling problem in a re-entrant hybrid flow shop with dynamic events (RHFS-GDS).The approach involves creating a green dynamic scheduling optimization model, which aims to minimize the makespan, total energy consumption, and stability of rescheduling solutions. A hybrid green scheduling decoding method is then employed to select machines for each operation and calculate fitness. Additionally, three neighborhood structures are designed to improve the population diversity and optimality of the MOEA-VNS algorithm. Two rescheduling strategies are also adopted to handle dynamic events that may occur during production. Experimental results demonstrate that these approaches are effective in solving the RHFS-GDS problem and can guide actual production. By incorporating dynamic events and rescheduling strategies into the optimization process, the proposed MOEA-VNS algorithm provides a comprehensive solution to the complex challenges faced by re-entrant hybrid flow shops in practical production environments.
Research on Simulation and Evaluation of Environmental Adaptability of Ribbon Bridge Based on GMRES Algorithm
Authors: Zhang Kaikai , Chen Shi , Tu JianGang , Feng Ke
Published: May 2024

This paper focuses on the safety of ribbon bridge navigation at different flow speeds, including bow tilt and stern tilt. By constructing a CAD 3 dimensions simulation model and CFD simulation test model of a ribbon bridge, the Hydrodynamics of the ribbon bridge under different load conditions and flow velocity is simulated and calculated based on the GMRES algorithm.The environmental adaptability assessment was carried out from the aspects of bow tilt, stern tilt and flow velocity adaptability of the ribbon bridge, and the navigation safety and stability of the ribbon bridge in different environments were obtained, which could provide data reference and support for the safe navigation of the ribbon bridge in the actual waters.
A Novel Time-frequency Representation Method: The Generalized W Transform
Authors: Liu Baotong , Liu Qiyuan , Kang Xuefu , Liu Donglin , Jiang Yingshuang
Published: May 2024

The time-frequency representation (TFR) of seismic data is an effective technology for the detection of hydrocarbon reservoirs. To obtain the TFR of a seismic trace, a mathematical transform tool must be used to perform the decomposition of the seismic trace. This paper introduces an effective time-frequency decomposition method: the generalized W transform (GWT). We prove that the GWT is not a strictly reversible mathematical transform. The numerical experiment of a simulated seismic trace shows that the reconstruction relative error of inverse GWT could reach up to 20%. Nevertheless, the time-frequency spectrum obtained from its forward transform is particularly suitable for identifying oil and gas reservoirs. The presented GWT has three advantages: (1) Its time-frequency spectrum has a high temporal resolution even at low frequencies; (2) The spectral centroid corresponds to the peak frequency of the wavelet; (3) It eliminates the singularity of the original W transform (WT) at the peak frequency of the waveform. Compared with the wavelet transform and the S transform, the generalized W transform can more accurately characterize reservoirs. A real data example illustrates that the GWT provides better TFR performance and can more effectively identify hydrocarbon reservoirs.
Simplified Coupled Calculation Method for Aeroelasticity of Large Flexible Aircraft
Authors: Hou Yingyu , Zhang Ning , Liu Ziqiang
Published: May 2024

Large flexible aircraft have the characteristics of large wingspan, low wing load, slow flight speed, and significant impact from gust loads. Therefore, the load and response issues of such aircraft have received widespread attention from scholars at home and abroad. This article establishes a simplified coupled calculation method for gust loads on large flexible aircraft, achieving coupled calculations of flight motion, structural deformation, and aerodynamic changes at different time steps. Due to the simple strip method used for aerodynamic modeling, this method is relatively fast compared to the CFD-CSD calculation method. In order to verify the accuracy of the method, the calculation results were compared with those of the standard calculation method. The comparative calculation results show that the simplified coupling calculation method is relatively accurate for this calculation example and can play an important role in engineering experiments with low requirements for calculation results.
A Novel Method for Stability and Stabilization of Interconnected Descriptor Systems
Authors: Jiang Xiong , Li Jian
Published: May 2024

This paper addresses the issues of stability and stabilization in interconnected descriptor systems. The existing results based on different structures of the Lyapunov equation are not directly applicable to resolving time-varying problems. In this paper, based on the original literature, the stability of the system is re-described and extended, and new results are obtained, these results are extended to encompass time-varying singular systems exhibiting state-space symmetry, which is achieved by introducing a novel Lyapunov functional. The approach in this paper is grounded in the theory of trace inequalities for matrices, establishing a new sufficient condition for the admissibility of interconnected descriptor systems. In the last, an illustrative example demonstrates the feasibility of employing state feedback to render interconnected descriptor systems admissible, affirming the validity of our proposed method.