bluuebunny/crossref_metadata_2025 huggingface dataset:
Herders without borders: transhumance securitisation and the challenges of national security in Ghana and Nigeria
Authors: Nwangwu Chikodiri
Published: November 2024

As an enduring agricultural practice in Africa, transboundary herding has remained a major source of conflict among agro-land users, especially between the Fulani nomadic pastoralists and peasant farmers/host communities. Although extant studies broadly agree that this herding practice is prone to violence, the actual factors which predispose this agricultural practice to violence vary across studies, ranging from climate change and environmental security, population growth and urbanisation, manipulation of cultural and ethnic identities, insecurity in the Lake Chad area, to the free movement of persons and goods protocols. However, these studies have glossed over how the securitisation of transhumance contributes to the conflict between nomadic herders and peasant farmers in West Africa—which is the focus of the present study. Data for this study were sourced from documentary evidence, including scholarly literature, media reports, and official documents from relevant protocols of the Economic Community of West African States. Relying on the basic assumptions of securitisation theory, the study found that transhumance securitisation as a default state response strategy against agro-land use conflicts between nomadic herders and peasant farmers has become counterproductive in West Africa.
Nonlinear interaction of first and second sounds in a solid
Authors: Pushkina N. I. , Zaitsev R. O.
Published: November 2024

The nonlinear interaction of first and second sounds in a solid is discussed. Canonical variables are found, and the Hamiltonian is expanded in powers of those variables. The Hamilton equations of motion, including second-order nonlinear terms, are obtained. The vertices and threshold intensities for the scattering of first sound by second sound and for the decay of first sound into two second sounds are calculated. It is shown that the threshold intensity for sound scattering is considerably higher than the decay threshold, which can be an experimentally attainable quantity.
Density of the normal component of He3–He4 solutions at elevated pressures
Authors: Sobolev V. I. , Esel’son B. N. , Nosovitskaya O. S. , Pogorelov L. A.
Published: November 2024

Measurements were made of the density of the normal component of He3–He4 solutions with He3 concentrations up to 13% at elevated pressures up to 20 atm. Measurements were performed at constant solution density over the temperature range from 0.4 °K to Tλ. The density dependence of the He3 quasiparticle effective mass was determined at elevated pressure.
Deviation from the law of corresponding states for ideal and nonideal superconductors
Authors: Ivanter I. G. , Malov Yu. A.
Published: November 2024

By using the Eliashberg equation an expression is found for the deviations from the law of corresponding states for an arbitrary form of the spectral function S(ω). Values of the ratio 2Δ (0)/Tc calculated in the Einstein model for Nb3Ge, Hg, and Pb are in good agreement with experimental results. Results of research applied for thin films with an adsorbed monolayer of impurity atoms showed that the deviations from the law of corresponding states can be significant for such systems.
Temperature of magnetic reorientation in SmxTb1−xFeO3 solid solutions
Authors: Sirota N. N. , Lomako I. D.
Published: November 2024

A study is made of the magnetic properties of SmxTb1–xFeO3 single crystals (x =0, 0.2, 0.4, 0.55, 0.8, and 1). On the basis of the results we determine the temperature ranges of spin reorientation in this system.
Light absorption dichroism and the magnetic configuration of weakly ferromagnetic CoCO3
Authors: Verdyan A. I. , Eremenko V. V. , Litvinenko Yu. G. , Shapiro V. V.
Published: November 2024

We have studied the dichroism of excitonic optical absorption in weakly ferromagnetic CoCO2. A correlation is demonstrated between the orientation of the antiferromagnetic vector l with respect to the C3 axis and the magnitude of the dichroism. It is shown that the vector l lies in the basal plane.
Spectral in situ ellipsometer for thin layer measurements in thermonuclear fusion applications
Authors: Krychowiak Maciej
Published: November 2024

Ellipsometry is widely used to characterize the thickness and optical parameters of thin films deposited, for example, in industrial processes. It is based on the measurement of polarization change upon reflection of, for example, visible light at a material sample. Commercially available devices are designed for stationary applications and often rely on precise geometric adjustment of the optical setup to maximize the measurement precision. In this work, a simplified spectral ellipsometer is proposed and tested with the aim of flexible implementation in space-limited applications in thermonuclear fusion research: on the one hand, as a hand-held device for large thickness scans of coatings deposited on first-wall components inside the vacuum vessel of fusion experiments and, on the other hand, for in situ monitoring of plasma deposited coatings on diagnostic vacuum windows, reducing their transmission in the optical spectral range, which hampers spectroscopic diagnostics in long-pulse plasma experiments. The simplicity of the hardware setup is partially compensated by complex Bayesian inference of the coating parameters, which incorporates all uncertainties of the measurement and the model and provides a quantitative assessment of the final uncertainties of inferred coating parameters. The Bayesian inference based on synthetic observations is also used to optimize the diagnostic design, identifying the limiting parameters and quantifying their impact on final accuracy. For real-time analysis of layer thickness on first-wall components in fusion devices measured with the hand-held device, a neural network based analysis has been implemented, and promising test results are presented.
Hybrid direct drive with a two-sided ultraviolet laser
Authors: Thomas C. A. , Tabak M. , Alexander N. B. , Galloway C. D. , Campbell E. M. , Farrell M. P. , Kline J. L. , Montgomery D. S. , Schmitt M. J. , Christopherson A. R. , Valys A.
Published: November 2024

This paper presents a “hybrid” approach to direct drive inertial confinement fusion that can exploit a high-energy gas laser with two opposed beams. The target and driver are asymmetric, much like experiments performed on the National Ignition Facility, but have been designed to benefit from scale and their particular compatibility with a fusion power plant. The imploded masses (and areal densities) are increased by a factor of 12 (3) relative to findings by Abu-Shawareb et al. [Phys. Rev. Lett. 129, 075001 (2022)] and provide a path to high-gain implosions that robustly ignite. The design also mitigates common concerns such as laser imprint and cross-beam energy transfer. We discuss the rationales for a hybrid target, the methods used to control implosion symmetry, and the implication(s) for inertial fusion energy.
Calorimetry probe for runaway electron heat load measurement at COMPASS
Authors: Caloud J. , Tomesova E. , Ficker O. , Cerovsky J. , Mlynar J. , Adamek J. , Barton P. , Bilkova P. , Bohm P. , Bousek M. , Brotankova J. , Duran I. , Entler S. , Havranek A. , Jerab M. , Kovarik K. , Krbec J. , Kulkov S. , Marcisovsky M. , Sos M. , Tadros M. , Tomes M. , Varavin M. , Vondracek P. , Weinzettl V. ,   COMPASS Team
Published: November 2024

Runaway electrons, accelerated in a tokamak discharge to high energies (tens of MeV), can cause serious damage to plasma facing components. Therefore, it is important to develop effective mitigation strategies to reduce the risk of tokamak damage. To study the effects of various mitigation strategies, a dedicated diagnostic, the calorimetry probe, was developed at the COMPASS tokamak. This probe successfully measured the heat loads caused by runaway electrons directly, using a set of temperature sensors embedded in a graphite body. Deposited energy measured by the probe ranged from a few hundred joules up to (15 ± 1) kJ, while the mean deposited energy was (4.5 ± 1.1) kJ. The design of the probe and the initial results from 250 discharges covering four experimental campaigns dedicated to runaway electron studies (2019–2021) are presented in this article.
A stochastic precipitating quasi-geostrophic model
Authors: Chen Nan , Mou Changhong , Smith Leslie M. , Zhang Yeyu
Published: November 2024

Efficient and effective modeling of complex systems, incorporating cloud physics and precipitation, is essential for accurate climate modeling and forecasting. However, simulating these systems is computationally demanding since microphysics has crucial contributions to the dynamics of moisture and precipitation. In this paper, appropriate stochastic models are developed for the phase-transition dynamics of water, focusing on the precipitating quasi-geostrophic (PQG) model as a prototype. By treating the moisture, phase transitions, and latent heat release as integral components of the system, the PQG model constitutes a set of partial differential equations (PDEs) that involve Heaviside nonlinearities due to phase changes of water. Despite systematically characterizing the precipitation physics, expensive iterative algorithms are needed to find a PDE inversion at each numerical integration time step. As a crucial step toward building an effective stochastic model, a computationally efficient Markov jump process is designed to randomly simulate transitions between saturated and unsaturated states that avoids using the expensive iterative solver. The transition rates, which are deterministic, are derived from the physical fields, guaranteeing physical and statistical consistency with nature. Furthermore, to maintain the consistent spatial pattern of precipitation, the stochastic model incorporates an adaptive parameterization that automatically adjusts the transitions based on spatial information. Numerical tests show the stochastic model retains critical properties of the original PQG system while significantly reducing computational demands. It accurately captures observed precipitation patterns, including the spatial distribution and temporal variability of rainfall, alongside reproducing essential dynamic features such as potential vorticity fields and zonal mean flows.
The influence of water polarization on slip friction at charged interfaces
Authors: Kunhunni Amith , Varghese Sleeba , Kannam Sridhar Kumar , Sathian Sarith P. , Daivis Peter J. , Todd B. D.
Published: November 2024

The present study employs equilibrium molecular dynamics simulations to explore the potential mechanism for controlling friction by applying electrostatic fields in nanoconfined aqueous electrolytes. The slip friction coefficient demonstrates a gradual increase corresponding to the surface charge density for pure water and aqueous electrolytes, exhibiting a similar trend across both nanochannel walls. An expression is formulated to rationalize the observed slip friction behavior, describing the effect of the electric field on the slip friction coefficient. According to this formulation, the slip friction coefficient increases proportionally to the square of the uniform electric field emanating from the charged electrode. This increase in slip friction results from the energy change due to the orientation polarization of interfacial water dipoles. The minimal variations in the empirically determined proportionality constant for pure water and aqueous electrolytes indicate that water polarization primarily governs slip friction at charged interfaces. These findings offer insights into the electrical effects on nanoscale lubrication of aqueous electrolytes, highlighting the significant role of water polarization in determining slip.
Understanding orientational disorder in crystalline assemblies of hard convex polyhedra
Authors: Kundu Sumitava , Chakraborty Kaustav , Das Avisek
Published: November 2024

Spontaneous self-assembly of hard convex polyhedra is known to form orientationally disordered crystalline phases, where particle orientations do not follow the same pattern as the positional arrangement of the crystal. A distinct type of orientational phase with discrete rotational mobility has been reported in hard particle systems. In this paper, we present a new analysis method for characterizing the orientational phase of a crystal, which is based on algorithmic detection of unique orientations. Using this method, we collected complete statistics of discrete orientations along the Monte Carlo simulation trajectories and observed that particles were equally partitioned among them, with specific values of pairwise orientational differences. These features remained constant across the pressure range and did not depend on rotational mobility. The discrete mobility was characteristic of a distinct equilibrium thermodynamic phase, qualitatively different from the freely rotating plastic phase with continuous orientations. The high pressure behavior with frozen particle orientations was part of that same description and not a non-equilibrium arrested state. We introduced a precise notion of orientational order and demonstrated that the system was maximally disordered at the level of a unit cell, even though individual particles could only take a few discrete orientations. We report the existence of this phase in five polyhedral shapes and in systematically curated shape families constructed around two of them. The symmetry mismatch between the particle and the crystallographic point groups was found to be a predictive indicator for the occurrence of this phase.
Comprehensive power loss analysis for hybrid distribution transformer
Authors: Sang Zixia , Zheng Xu , Lei He , Yan Jiong , Cai Jie , Fang Rengcun
Published: November 2024

Compared with traditional power transformers, Hybrid Distribution Transformers (HDTs) generate higher power losses due to the application of power electronic converters. However, HDTs can apply reactive power compensation as well as three-phase load current unbalance compensation, which leads to line loss reduction of the distribution power grid. When comparing the power losses of HDTs and traditional transformers, it is necessary to comprehensively consider the operational power loss of HDTs and line losses of the distribution network reduced by its converter. This article proposes a comprehensive loss model for the application of HDTs in distribution networks and conducts theoretical calculations on HDT self-losses and distribution network line losses caused by reactive power and three-phase asymmetric load currents. The power losses on the transmission wire of the distribution power grid with the application of HDTs instead of traditional transformers are analyzed. The calculation and simulation results based on parameters such as reactive power, three-phase unbalanced current, and HDT comprehensive loss have verified the correctness of the theoretical analysis.
Source distribution correlation enabled self-attention residual network for effective reconstruction of optical molecular tomography
Authors: Wang Lin , Xiao Yahui , Pan Chenrui , Cao Xin , Zhao Minghua
Published: November 2024

As a promising preclinical imaging technique, optical molecular tomography (OMT) shows great potential in early detection and diagnosis of tumor diseases. However, its widespread application has been hindered by the limitations of traditional reconstruction methods, specifically the accuracy of optical transmission models and the ill-posed nature of inverse reconstruction. The development of deep learning has offered novel solutions for OMT, enabling efficient reduction of the ill-posed nature in reconstruction. The existing deep learning approaches employ conventional neural networks and objective functions, which retains significant scope for enhancing the accuracy of image reconstruction. In this paper, we propose a source distribution correlation enabled self-attention residual network (DCeSR network) to address the need for accurate OMT reconstruction. The DCeSR network leverages a residual learning strategy and a self-attention mechanism to effectively integrate the deep and shallow features, subsequently extracting highly informative surface measurements to accurately predict the three-dimensional distribution of light sources within tissues. The efficacy of the DCeSR network was validated through training and testing with two distinct numerical simulated datasets, each encompassing both single and dual source configurations. Both qualitative and quantitative analyses demonstrate the superior performance of the DCeSR network in achieving accurate OMT reconstructions.
Continuous flow of a thixotropic elasto-viscoplastic-banded structured fluid: Exponential structure rheological constitutive equation
Authors: Ramírez-Torres L. A. , Herrera-Valencia E. E. , Soriano-Correa C. , Sánchez-Villavicencio M. L. , Campos-Fernández L. , Ascanio G. , Hernández-Abad V. J. , Calderas F.
Published: November 2024

In this work, the viscoelastic behavior of a complex structured liquid in a continuous squeeze flow is analyzed. This flow is simulated allowing a continuous flow of liquid into the narrow gap between two circular plates though the lower plate. The complex liquid is characterized by the exponential structure rheological (ESR) constitutive equation, which is a generalized exponential thixotropic-elasto-viscoplastic-banded model, chosen for this study due to its capacity to predict non-Newtonian and complex behavior such as (i) shear-thinning, (ii) shear-thickening, (iii) yield stress, (iv) thixotropy, (iv) rheopexy, and (v) shear banding flow behavior. The exponential rheological equation of state is defined by a class of exponential Phan-Thien–Tanner-type models, which includes specific cases documented in the literature. The viscoelastic, kinetic, and structural mechanisms in the ESR model are characterized by the association of non-dimensional numbers to each mechanism. To solve the set of non-linear partial differential equations, a perturbation scheme is suggested, based on a small parameter that represents the ratio between two characteristic lengths. At zeroth order (neglecting the inertial mechanisms of the momentum equation), it is found that the normal force on the upper disk is directly related to shear dependent viscosity (thixotropy, shear-thinning, shear-thickening, yield stress behavior, and concentration effects). At first order, the normal force is related to the effects of the elasticity, and it is parallel to the first normal stress difference associated with the elasticity of the ESR structured fluid.
Advanced fabrication process for particle absorbers of highly pure electroplated gold for microcalorimeter applications
Authors: Müller Michael , Zühlke Ria-Helen , Kempf Sebastian
Published: November 2024

Magnetic microcalorimeters (MMCs) have become a key technology for applications requiring outstanding energy resolution, fast signal rise time and excellent linearity. MMCs measure the temperature rise upon absorption of a single particle within a particle absorber by using a paramagnetic temperature sensor that is thermally coupled to the absorber. The design and fabrication of the particle absorber is key for excellent detector performance. Here, we present a microfabrication process for free-standing particle absorbers made of two stacked and independently electroplated high-purity Au layers. This enables, for example, the embedding of radioactive sources within the absorber for realizing a 4π detection geometry in radionuclide metrology or preparing detector arrays with variable quantum efficiency and energy resolution as requested for future applications in high-energy physics. Due to careful optimization of photoresist processing and electroplating parameters, the Au films are of very high purity and very high residual resistivity ratio values above 40, allowing for fast internal absorber thermalization.
A hybrid surface controls where frost forms
Authors: Sieben Jennifer
Published: November 2024

A textured honeycomb surface coated in graphene oxide remains frost-free for longer than other specialized materials.
Soils for Landscape Development
Authors: Leake Simon , Haege Elke
Published: November 2024

This second edition of the award-winning Soils for Landscape Development provides a globally applicable method for landscape architects and designers, specification writers, landscape contractors, nursery growers, turf specialists and soil supply companies to properly specify landscape soils using objective and measurable criteria. It uses systematic, clear and practical templates.

The book links landscape design processes with sound modern soil science practices to promote better quality project outcomes by ensuring that the basis of the landscape, the soil, is suitable for the intended purpose. The authors emphasise environmental impacts through site soil reuse, promoting appropriate minimal soil intervention and using recycled products, with example compliance specifications.

Key features:

Provides 14 updated performance-based soil and compliance specifications including on ultra lightweight green roof soil, high fertility display and vegetable production topsoil and biofiltration soil.
Includes new sections on low budget landscapes, small projects and soil fundamentals for landscape architects and designers.
The authors were awarded the 2015 Australian Institute of Horticulture (AIH) Literature Award and the 2014 Australian Institute of Landscape Architecture (AILA) NSW Research and Development Award for the first edition of this book.
Diversification of pectoral control through motor pool extension
Authors: Gutjahr Ruth , Bothe Maximilian S. , Jonsson Thorin , Chagnaud Boris P.
Published: November 2024

Flexible control of pectoral appendages enables motor behaviors of vastly different strength, speed, and amplitude, as in a human playing the piano or throwing a ball. Such control necessitates a fine-tuned, coordinated activation of motoneurons, which is facilitated by spatially ordered motoneuron pools in mammals. While differently sized neurons are known to contribute to different strengths of pectoral movements, it remains unclear how these pectoral motor pools are organized in less complex pectoral systems as those of teleost fish. We show how pectoral motor control can be extended to increase the speed- and amplitude-range of motor behaviors by investigating anatomical and physiological features of pectoral motoneurons and the motor pools they form in freshwater hatchet fish, well-known for their pectoral aerial escape response. Through the differentiation of one motor pool, the pectoral motor network of hatchet fish acquired additional flexibility to enable specific control of vastly different amplitudes, velocities, and strengths. Similar neuronal organization patterns have been described for controlling fast, intermediate, and slow axial muscles in zebrafish and in tetrapod motor systems controlling pectoral limbs. We show that hatchet fish share organizational principles of their pectoral motor pools with those found in other motor networks in both teleosts and tetrapods. Our data thus suggest that principles of spatial and physiological differentiation of motor pools associated with different pectoral muscles and behaviors might be deeply homologous between actinopterygian and sarcopterygian vertebrates.
Species-wide inventory of
Arabidopsis thaliana
organellar variation reveals ample phenotypic variation for photosynthetic performance
Authors: Theeuwen Tom P. J. M. , Wijfjes Raúl Y. , Dorussen Delfi , Lawson Aaron W. , Lind Jorrit , Jin Kaining , Boekeloo Janhenk , Tijink Dillian , Hall David , Hanhart Corrie , Becker Frank F. M. , van Eeuwijk Fred A. , Kramer David M. , Wijnker Erik , Harbinson Jeremy , Koornneef Maarten , Aarts Mark G. M.
Published: November 2024

Efforts to improve photosynthetic performance are increasingly employing natural genetic variation. However, genetic variation in the organellar genomes (plasmotypes) is often disregarded due to the difficulty of studying the plasmotypes and the lack of evidence that this is a worthwhile investment. Here, we systematically phenotyped plasmotype diversity using
Arabidopsis thaliana
as a model species. A reanalysis of whole-genome resequencing data of 1,541 representative accessions shows that the genetic diversity among the mitochondrial genomes is eight times lower than among the chloroplast genomes. Plasmotype diversity of the accessions divides the species into two major phylogenetic clusters, within which highly divergent subclusters are distinguished. We combined plasmotypes from 60
A. thaliana
accessions with the nuclear genomes (nucleotypes) of four
A. thaliana
accessions to create a panel of 232 cytonuclear genotypes (cybrids). The cybrid plants were grown in a range of different light and temperature conditions and phenotyped using high-throughput phenotyping platforms. Analysis of the phenotypes showed that several plasmotypes alone or in interaction with the nucleotypes have significant effects on photosynthesis and that the effects are highly dependent on the environment. Moreover, we introduce Plasmotype Association Studies (PAS) as a method to reveal plasmotypic effects. Within
A. thaliana,
several organellar variants can influence photosynthetic phenotypes, which emphasizes the valuable role this variation has on improving photosynthetic performance. The increasing feasibility of producing cybrids in various species calls for further research into how these phenotypes may support breeding goals in crop species.
Caenorhabditis elegans
inositol hexaphosphate pathways couple to RNA interference and pathogen defense
Authors: Xu Wenjing , Sun Yifan , Breen Peter , Ruvkun Gary , Mao Kai
Published: November 2024

RNA interference (RNAi) is an evolutionarily conserved pathway that defends against viral infections in diverse organisms.
Caenorhabditis elegans
mutations that enhance RNAi have revealed pathways that may regulate antiviral defense. A genetic screen for
C. elegans
mutations that fail to up-regulate a defense response reporter transgene detected mutations that enhance RNAi to silence this reporter gene in the inositol polyphosphate multikinase
impk-1
, the synMuv B gene
lin-15B,
and the pathogen defense response gene
pals-22
. Using other assays for enhanced RNAi, we found that the
impk-1
alleles and an
ippk-1
gene inactivation of a later step in inositol hexaphosphate (IP
6
) synthesis, and the
lin-15B
and
pals-22
alleles enhance RNAi. IP
6
has been known for decades to bind and stabilize human adenosine deaminase that acts on RNA (ADAR) as well as the paralog tRNA editing ADAT. We show that the
C. elegans
IP
6
pathway is also required for mRNA and tRNA editing. Thus, a deficiency in two axes of RNA editing enhances the already potent
C. elegans
RNAi antiviral defense, suggesting adenosine to inosine RNA editing may normally moderate this siRNA antiviral defense pathway. The
C. elegans
IP
6
-deficient mutants are synthetic lethal with a set of enhanced RNAi mutants that act in the polyploid hypodermis to regulate collagen secretion and signaling from that tissue, implicating IP
6
signaling especially in this tissue. This enhanced antiviral RNAi response uses the
C. elegans
RIG-I-like receptor DRH-1 to activate the unfolded protein response (UPR). The production of primary siRNAs, rather than secondary siRNAs, contributes to this activation of the UPR through XBP-1 signaling. The
gon-14
and
pal-17
mutants that also emerged from this screen act in the mitochondrial defense pathway rather than by enhancing RNAi.
A sodium channel mutant removes fast inactivation with the inactivation particle bound
Authors: Liu Yichen , Bezanilla Francisco
Published: November 2024

Fast inactivation is a key feature of voltage-gated sodium channels and is pivotal for countless physiological functions. Despite the prevalence of the canonical ball-and-chain model, more recent structural results suggest that fast inactivation requires multiple conformational changes beyond the binding of the inactivation particle, the IFM motif. Combining ionic current, gating current, and fluorescent measurements, here we showed that a double mutant at the bottom of the pore domain (CW) removes fast inactivation by interrupting the communication of the IFM motif and the pore. Instead of triggering fast inactivation, the IFM motif binding in CW allows the channel to enter an alternative open state. This alternative open state severely influenced the voltage sensor movements and was not accessible to wild type or other fast inactivation–deficient channels. Our results highlight the multistep nature of the fast inactivation process in mammalian voltage-gated sodium channels and demonstrate that CW modifies the channel behaviors more profoundly than simple removal of fast inactivation.
Recent progress on multiferroic hexagonal rare-earth ferrites (h-RFeO3, R = Y, Dy-Lu)
Authors: Li Xin , Yun Yu , Xu Xiaoshan
Published: November 2024

Multiferroic hexagonal rare-earth ferrites (h-RFeO3
, R= Sc, Y, and rare earth), in which the improper ferroelectricity and canted antiferromagnetism coexist, have been advocated as promising candidates to pursue the room-temperature multiferroics, because of strong spin-spin interaction. The strong interactions between the ferroic orders and the structural distortions are appealing for high-density, energy-efficient electronic devices. Over the past decade, remarkable advances in atomic-scale synthesis, characterization, and material modeling enable the significant progresses in the understanding and manipulation of ferroic orders and their couplings in h-RFeO3 thin films. These results reveal a physical picture of rich ferroelectric and magnetic phenomena interconnected by a set of structural distortions and spin-lattice couplings, which provides guidance for the control of ferroic orders down to the nano scale and the discovery of novel physical phenomena. This review focus on state-of-the-art studies in complex phenomena related to the ferroelectricity and magnetism as well as the magnetoelectric couplings in multiferroic h-RFeO3, based on mostly the recent experimental efforts, aiming to stimulate fresh ideas in this field.
Measurement of atomic oxygen densities using TALIF on a dielectric barrier discharge: insights into the volume above a micro cavity plasma array
Authors: Steuer David , Bentz Brian Z , Youngman Kevin , van Impel Henrik , Böke Marc , Schulz-von der Gathen Volker , Golda Judith
Published: November 2024

Dielectric barrier discharges, particularly micro cavity plasma arrays, offer significant potential for plasma-catalytic research due to their ability to ignite plasma in direct contact with a catalytic surface, enabling the observation of plasma-surface interactions. A key factor in their application is the generation of reactive species, such as atomic oxygen, within the cavities. These species can interact with both the surface (e.g. for activation or cleaning) and the gas being treated (e.g. for oxidation). Given the central role of oxygen atoms in plasma catalysis and their use as a model for more complex species, this work investigates the transport of these atoms out of the cavities. Two-photon absorption laser-induced fluorescence spectroscopy with picosecond laser excitation is performed in the volume above the cavities. The results are compared with a basic diffusion model. The reactor operates with a He/O2 mixture at a flow rate of 1 slm and atmospheric pressure. Densities of up to 1016 cm−3 are measured near the surface. Time-dependent measurements show that, at a distance of 350 µm from the surface, a density equilibrium is reached within less than 3 ms of reactor operation. Decay times due to ozone formation after the reactor is turned off are on a similar scale. Spatially resolved measurements show that the oxygen density decreases exponentially from the surface but remains detectable up to approximately 1 mm above the surface, indicating significant application potential. Variations in the O2 admixture show a density maximum at 0.4%, confirming previous helium state enhanced actinometry measurements within the cavities.
Measurements of the Solar Coronal Magnetic Field Based on Coronal Seismology with Propagating Alfvénic Waves: Forward Modeling
Authors: Gao Yuhang , Tian Hui , Van Doorsselaere Tom , Yang Zihao , Guo Mingzhe , Karampelas Konstantinos
Published: November 2024

Recent observations have demonstrated the capability of mapping the solar coronal magnetic field using the technique of coronal seismology based on the ubiquitous propagating Alfvénic/kink waves through imaging spectroscopy. We established a magnetohydrodynamic model of a gravitationally stratified open magnetic flux tube, exciting kink waves propagating upwards along the tube. Forward modeling was performed to synthesize the Fe xiii 1074.7 and 1079.8 nm spectral line profiles, which were then used to determine the wave phase speed, plasma density, and magnetic field with seismology method. A comparison between the seismologically inferred results and the corresponding input values verifies the reliability of the seismology method. In addition, we also identified some factors that could lead to errors during magnetic field measurements. Our results may serve as a valuable reference for current and future coronal magnetic field measurements based on observations of propagating kink waves.
Divertor footprint modeling due to RMP in HL-2A and role of plasma response
Authors: Dong G.Q. , Liu Y.Q. , Hao G.Z. , Zhang S.L. , Wu N. , Gao J.M. , Sun T.F. , Wang A. , Wang S. , Zhang N. , Wang L. , Li C.Y.
Published: November 2024

The divertor heat flux footprint is modeled for the HL-2A discharge, in the presence of the resonant magnetic perturbation (RMP) applied to control the edge-localized mode. Both the magnetic field lines and the guiding-center drift orbits of test thermal ions are traced, based on the computed plasma response to the RMP. Toroidal modeling identifies a reason—a vertical shift of the plasma separatrix—for the observed upper shift of the heat flux footprint during the initial phase of the RMP application in the experiment. While both the field-line tracing and particle orbit tracing replicate the experimental observation reasonably well, the latter approach is found to produce results that better align with the measured heat flux peaking along the divertor leg. A sensitivity investigation of the simulated footprint location and width against the assumed plasma response models—the conventional fluid model, the fluid model with strong parallel sound wave damping (SWD), and magnetohydrodynamic-kinetic hybrid mode—reveals that the fluid model with SWD yields the best agreement with the experiment, due to the fact that this model produces a stronger field response inside the plasma. These toroidal modeling results, while helping explain and interpret the experimental observations in HL-2A, provide physics insight to guide divertor footprint control via RMP in the future high-performance experiments in devices such as HL-3.
Analysis of thermal protection effect and lip passivation of forward-facing cavity at high Mach number
Authors: Duan Zhenkun , Peng Wuyu , Liu Wei
Published: November 2024

With the development of various technologies, the demand for high Mach number (Mach number greater than 8) aircraft is increasing. The requirements for hypersonic drag reduction and thermal protection are constantly increasing. At the present stage, there are relatively few researches on hypersonic drag reduction and thermal protection schemes considering the real gas effect. It is necessary to further study the flow characteristics and rules, and the applicability of drag reduction and thermal protection schemes under high Mach numbers. In this paper, the cylindrical and spherical shapes with Mach 16.5 are simulated. A series of studies are carried out on the forward-facing cavity. It is concluded that the forward-facing cavity can provide a good thermal protection effect, but the drag reduction effect is not good. What is more, the space of the cavity is larger, the diameter is longer, the ratio of the depth and length of the cavity is smaller, and the thermal protection effect is better. In addition, the lip passivation of different configurations of shallow cavity and deep cavity was studied. It is found that different shapes have different results.
Global reliability sensitivity analysis based on subset simulation and space partition method
Authors: Zhao Xiang
Published: November 2024

The global reliability sensitivity analysis assesses how the model’s failure probability is impacted by uncertainty in input variables, and the importance ranking obtained by the analysis can directly provide effective information on how to decrease the structure’s failure probability. The subset simulation method is combined with the space partition method to solve the variables’ significance measure to overcome the problem of low computational efficiency of traditional methods. In accordance with the failure probability of the subset simulation calculation, the samples generated by this process are statistically processed by the space partition method. Based on the features of stratified sampling in subset simulation, the formula of applicable conditional expectation is derived with the probability stratification information as the weight so as to calculate the random variables’ first-order global reliability sensitivity index. Because the quantity of samples utilized in the proposed method is independent of the dimensions of the problem, the computation’s effectiveness is effectively raised. Ultimately, the suggested approach’s validity is confirmed through a practical example.
Unified automatic construction method of multi-source language functional mock-up unit
Authors: Liu Xi , Wang Xi , Yu Bowei
Published: November 2024

Model simulation plays an important role in modern engineering design and system development. It simulates and validates complex systems through a virtual environment, reduces the cost and risk of physical tests, and improves the design efficiency and accuracy. Generating a functional mock-up unit (FMU) is the core of model simulation. Most FMU is generated by Modelica, but this generation method is not only very complicated but also requires experimentalists to be familiar with Modelica. Nowadays, physical models are becoming more and more complex. With the development of artificial intelligence, more and more intelligent models are involved in the simulation process. Therefore, it is essential to realize the simulation process of automatic and rapid generation of FMU by multi-source languages. In this paper, by combining Python and Modelica, two methods of automatic FMU generation are designed. Through simulation tests, it is verified that the FMU generated by these two methods can be applied to the simulation process, which brings significant efficiency improvement to the model design.
Partition-based outlier detection for high dimensional data
Authors: Zhang Jutian , Yang Xiaona , Wang Xin
Published: November 2024

Outlier detection has become increasingly important for high dimensional data (HDD) before data analysis. Although the multivariate outlier detection methods (ODMs) have been extensively studied in the research literature, there are few ODMs for ODMs when a correlation exists between data’s components. In this paper, we introduce a partition-based estimator of the minimum covariance determinant for HDD, along with a rapid algorithm designed to identify the clean subset. Additionally, an OD threshold is employed by examining the asymptotic distribution of the outlying measure distance to pinpoint outliers. Moreover, a one-step reweighting scheme is introduced to enhance the detection efficiency of the process. At last, simulation results demonstrate that the proposed RPMCD methods exhibit superior finite sample performance compared to other existing techniques.
Study on the change of reservoir seepage flow by microbial oil drive in the reservoir after polydynamic drive
Authors: Qu Changyue , Liu Zhenyu , Lv Anqi , Yang Yan
Published: November 2024

Microbial drive is an effective technical means to enhance low-permeability reservoirs. There is a large amount of residual oil in the reservoir after polydrive, so there is an urgent need to explore effective ways to improve the recovery rate. Combining the actual needs of the XK well area and the characteristics of microbial oil recovery technology, we carried out the numerical simulation study of microbial drive and evaluated the changes in seepage capacity of the reservoir and typical wells at different stages. The results show that in the first cycle of microbial injection, the seepage capacity around the injection wells is obviously improved, but the seepage capacity of each reservoir in the second cycle is not improved as well as that in the first cycle; the improvement of seepage capacity around the injection wells is related to the permeability of the reservoirs and the effective thickness; the higher the permeability and the thicker the effective thickness are, the faster the seepage capacity of the near-well zones is improved, and the bigger the improvement amplitude is, and the earlier the production wells nearby are able to see the effect. This study provides guidance for field tests and is of great significance for the improvement of reservoir recovery after polydynamic drive.
Mathematical analysis based on SAIQRS model
Authors: Ji Meng
Published: November 2024

Given the mobility of the population during epidemic transmission, the lethality of certain epidemics, and the fact that recovered individuals do not possess lifelong immunity, it is crucial to consider vaccination strategies to control epidemic spread. Vaccinating the population stimulates the production of antibodies, thereby reducing the disease transmission rate. Furthermore, individuals who have been infected with the same pathogen as the vaccine will generate a certain amount of antibodies, enhancing their resistance to future epidemics. In this paper, we develop a susceptible-antibodies-infected-isolated-removed-individuals (SAIQRS) model and derive the basic regeneration number R
0 for the deterministic SAIQRS model. Next, the effect of the stochastic factor is taken into account by changing the transmission rate β
1 → β
1 + σB(t), which extends the model to a stochastic SVIQRS model and gives the conditions for the extinction and persistence of the disease. Finally, the theorems of the deterministic and stochastic models are verified by numerical simulations.
Visual SLAM based on visual odometry feature extraction and real-time rendering of neural radiance fields
Authors: Xu Jun , Li Yuhang , Wu Xiaohua
Published: November 2024

In response to the limitation of traditional feature-based Visual SLAM, which focuses primarily on camera pose accuracy while neglecting the refinement of 3D map reconstruction, this paper proposes a Visual SLAM system called ON-SLAM (Simultaneous Localization and Mapping). The aim is to develop a Visual SLAM system that does not require pre-training, can quickly adapt to new and changing environments, and can generate dense point cloud maps in real time. Currently, both learning-based and non-learning-based methods fall short of these requirements due to their algorithmic limitations. The ON-SLAM framework integrates visual odometry technology with implicit neural representations to achieve real-time localization and high-precision map construction. This system is compatible with monocular cameras and relies solely on RGB inputs, demonstrating enhanced applicability in real-world scenarios. Experimental results show that ON-SLAM achieves state-of-the-art accuracy in both localization and map construction.
Approximate controllability of semilinear MFDEs with infinite delay
Authors: Cao Yueju
Published: November 2024

This paper develops the theory of approximate controllability for semilinear MFDEs (measure functional differential equations) with infinite delay within Hilbert spaces. The derivation of the criteria for the approximate controllability of these systems is achieved by constructing a suitable phase space framework and utilizing the theory of C
0 semigroup and fixed points. Finally, a comprehensive example is presented to elucidate our findings.
Robust model predictive bipartite consensus control for cooperation-competition MASs under DoS attacks
Authors: Zhang Jinnan , Hu Zhongrui , Zhang Songyuan , Dong Hongli
Published: November 2024

This paper addresses the bipartite consensus control problem for a class of discrete-time cooperation-competition multi-agent systems (MASs) subject to denial-of-service (DoS) attacks under the robust model predictive control (RMPC) framework. A signed graph is characterized to describe the cooperation-competition relationship, and the edges of the graph have either positive or negative connection weights. A DoS attacker accomplishes their objectives by obstructing the communication channel between the controller and the actuator. Meanwhile, with the goal of achieving accurate bipartite consensus, an observer-based RMPC algorithm is aimed to be designed in the context of the DoS attacks, which ensures the recursive feasibility and input-to-state stability (ISS) in the mean square sense. The effectiveness of the algorithm is verified by an example in the end.
Conformal prediction with censored data using Kaplan-Meier method
Authors: Sun Xiaolin , Wang Yanhua
Published: November 2024

In this paper, we introduce a prediction algorithm founded on conformal prediction, tailored for constructing prediction intervals in the context of censored survival data. Conformal prediction frameworks distinguish themselves from other prediction paradigms by their non-empirical evaluation, reliance on user-defined confidence intervals for modeling errors, and widespread adoption across regression and classification methodologies, inclusive of survival analysis, in recent years. Herein, we present a novel application wherein the Kaplan-Meier method is employed to compute empirical quantiles of nonconformal scores, specifically tailored for censored schematic variables. This novel approach facilitates the generation of well-calibrated prediction intervals for survival times, augmenting any existing survival prediction algorithm. Validation of its efficacy and computational efficiency is performed on both the real-world dataset ‘SUPPORT’ and the synthetic dataset ‘RRNLNPH.’
Research on overlapping community detection algorithm of label propagation based on node pair extension
Authors: Yan Huizi , Feng Yu , Zhang Weiqi , Xue Bowen , Li Jinrong
Published: November 2024

Community detection is a data analysis method used to reveal the aggregation behavior of the network. This paper improves the COPRA algorithm and proposes a PECOPRA algorithm with better performance to solve the problem. R-mcl similarity coefficient matrix is calculated in the pre-processing operation, the Pearson correlation matrix representing the node relationship is calculated, and the Pearson correlation matrix is filtered to obtain the result matrix. On this basis, the COPRA algorithm is used to calculate and map the community, and the extended modularity redivides the boundary nodes to improve the community partition accuracy. PECOPRA improves the accuracy of community detection quality and has better performance.
Generation of distribution network topology based on the LASSO algorithm
Authors: Li Guocheng , Hu Guorui , Cui Haichao , Lu Zeguang , Li Xiaoran , Li Zhimin , Lei Jiakun , Xu Linyu
Published: November 2024

A new method for intelligent generation of distribution network topology is proposed to address the challenge of monitoring the distribution network topology. Initially, the Least Absolute Shrinkage and Selection Operator (LASSO) technique is applied to calculate the correlation matrix among buses in the distribution grid. Through simulations, it has been shown that this method can effectively and precisely generate distribution network structures, both with and without loops, using time-series voltage data, even when prior knowledge of the network is not available.