bluuebunny/crossref_metadata_2025 huggingface dataset:
Toponymic surnames and the spatiality of heresy prosecutions: Peter Seila’s register of sentences from the Quercy region (Languedoc), 1241–1242
Authors: Shaw Robert L. J. , Sikk Kaarel , Zbíral David
Published: February 2024

Our knowledge of the geography of medieval religious dissent and its repression in the Latin West is limited by a lack of systematic study of locational information in inquisition trial records. Spatial analysis of these rich details has the potential to help build a bottom-up picture of interaction between dissidents and inquisitors that moves beyond institutional perspectives. This task is rendered challenging due to the inconsistencies and uncertainties of what inquisitors and their notaries typically recorded about the spatial associations of suspects. Probably the most common indicator of such associations found in inquisition records are toponymic surnames. They present challenges of coverage (not everybody had a toponymic surname) and interpretation (multiple possible meanings). This study attempts to tackle the challenge of interpreting such surnames within the context of the nine sentencing events held by the inquisitor Peter Seila in 1241 and 1242 in the Quercy region of Languedoc: covering 650 sentenced individuals, the register documenting these events is the earliest extant record of an inquisition of such scale. Rather than taking the interpretative challenges of toponymic surnames as reasons to limit ourselves to qualitative analysis, our approach shows the value of rendering and analysing them as structured data. Firstly, we quantify the context of toponymic surnames, placing them against the background of broader name construction practices and other social factors. Secondly, we plot and analyse the geocoded data derived from toponymic surnames with the benefit of this contextualisation, looking especially at the distance of toponyms from their associated sentencing centres, in order to derive narratives that best explain the generality of their meaning. The results allow us to appraise the actual spatial coverage of the nine sentencing events. The first two, centred on the important towns of Montauban and Moissac, seem most likely to have been primarily urban affairs, with little evidence of rural coverage. The remainder, which took place incastra(fortified villages), appear to have covered more of the surrounding countryside. These results geographically contextualise the reports of dissidence conveyed within Peter’s register, and suggest narratives for how Peter optimised his strategy for impact in the face of constraints.
Viral afterlife: SARS-CoV-2 as a reservoir of immunomimetic peptides that reassemble into proinflammatory supramolecular complexes
Authors: Zhang Yue , Bharathi Vanthana , Dokoshi Tatsuya , de Anda Jaime , Ursery Lauryn Tumey , Kulkarni Nikhil N. , Nakamura Yoshiyuki , Chen Jonathan , Luo Elizabeth W. C. , Wang Lamei , Xu Hua , Coady Alison , Zurich Raymond , Lee Michelle W. , Matsui Tsutomu , Lee HongKyu , Chan Liana C. , Schepmoes Athena A. , Lipton Mary S. , Zhao Rui , Adkins Joshua N. , Clair Geremy C. , Thurlow Lance R. , Schisler Jonathan C. , Wolfgang Matthew C. , Hagan Robert S. , Yeaman Michael R. , Weiss Thomas M. , Chen Xinhua , Li Melody M. H. , Nizet Victor , Antoniak Silvio , Mackman Nigel , Gallo Richard L. , Wong Gerard C. L.
Published: February 2024

It is unclear how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to the strong but ineffective inflammatory response that characterizes severe Coronavirus disease 2019 (COVID-19), with amplified immune activation in diverse cell types, including cells without angiotensin-converting enzyme 2 receptors necessary for infection. Proteolytic degradation of SARS-CoV-2 virions is a milestone in host viral clearance, but the impact of remnant viral peptide fragments from high viral loads is not known. Here, we examine the inflammatory capacity of fragmented viral components from the perspective of supramolecular self-organization in the infected host environment. Interestingly, a machine learning analysis to SARS-CoV-2 proteome reveals sequence motifs that mimic host antimicrobial peptides (xenoAMPs), especially highly cationic human cathelicidin LL-37 capable of augmenting inflammation. Such xenoAMPs are strongly enriched in SARS-CoV-2 relative to low-pathogenicity coronaviruses. Moreover, xenoAMPs from SARS-CoV-2 but not low-pathogenicity homologs assemble double-stranded RNA (dsRNA) into nanocrystalline complexes with lattice constants commensurate with the steric size of Toll-like receptor (TLR)-3 and therefore capable of multivalent binding. Such complexes amplify cytokine secretion in diverse uninfected cell types in culture (epithelial cells, endothelial cells, keratinocytes, monocytes, and macrophages), similar to cathelicidin’s role in rheumatoid arthritis and lupus. The induced transcriptome matches well with the global gene expression pattern in COVID-19, despite using <0.3% of the viral proteome. Delivery of these complexes to uninfected mice boosts plasma interleukin-6 and CXCL1 levels as observed in COVID-19 patients.
Decoupling particle-impact dissipation mechanisms in 3D architected materials
Authors: Butruille Thomas , Crone Joshua C. , Portela Carlos M.
Published: February 2024

Ultralight architected materials enabled by advanced manufacturing processes have achieved density-normalized strength and stiffness properties that are inaccessible to bulk materials. However, the majority of this work has focused on static loading and elastic-wave propagation. Fundamental understanding of the mechanical behavior of architected materials under large-deformation dynamic conditions remains limited, due to the complexity of mechanical responses and shortcomings of characterization methods. Here, we present a microscale suspended-plate impact testing framework for three-dimensional micro-architected materials, where supersonic microparticles to velocities of up to 850 m/s are accelerated against a substrate-decoupled architected material to quantify its energy dissipation characteristics. Using ultra-high-speed imaging, we perform in situ quantification of the impact energetics on two types of architected materials as well as their constituent nonarchitected monolithic polymer, indicating a 47% or greater increase in mass-normalized energy dissipation under a given impact condition through use of architecture. Post-mortem characterization, supported by a series of quasi-static experiments and high-fidelity simulations, shed light on two coupled mechanisms of energy dissipation: material compaction and particle-induced fracture. Together, experiments and simulations indicate that architecture-specific resistance to compaction and fracture can explain a difference in dynamic impact response across architectures. We complement our experimental and numerical efforts with dimensional analysis which provides a predictive framework for kinetic-energy absorption as a function of material parameters and impact conditions. We envision that enhanced understanding of energy dissipation mechanisms in architected materials will serve to define design considerations toward the creation of lightweight impact-mitigating materials for protective applications.
Contrasting the semantics of prepositions through a cognitive linguistic approach
Authors: Kalyuga Marika , Yunusova Sofya
Published: February 2024

Many studies on cognitive-semantic analysis focus on the patterns of polysemy of prepositions and the explanation
of how the multiple senses of prepositions are related in systematic ways. Only a few publications pay attention to the
contrastive analysis of prepositions in different languages. The article addresses this gap in research literature and aims: to
present a contrastive analysis of the English preposition on and its Italian and Russian partial equivalents in
order to uncover the main areas of semantic asymmetry between them; to compare patterns of semantic extensions (from spatial to
nonspatial senses) of these prepositions, and to determine how the similarities and differences in their spatial senses explain
the similarities and differences in their nonspatial senses. The article follows a conceptual metaphor approach. Since most of the
conceptual metaphors and metonyms are common cross-linguistically, similarities in patterns of semantic extensions of prepositions
can be explained through the conceptual metaphors and metonymies on which these extensions are based. The article also
demonstrates how the similarities and differences in spatial senses of the English preposition on, Italian
su, and Russian na explain the similarities and differences in their nonspatial senses.
A Bayesian approach for consistent reconstruction of inclusions
Authors: Afkham B M , Knudsen K , Rasmussen A K , Tarvainen T
Published: February 2024

This paper considers a Bayesian approach for inclusion detection in nonlinear inverse problems using two known and popular push-forward prior distributions: the star-shaped and level set prior distributions. We analyze the convergence of the corresponding posterior distributions in a small measurement noise limit. The methodology is general; it works for priors arising from any Hölder continuous transformation of Gaussian random fields and is applicable to a range of inverse problems. The level set and star-shaped prior distributions are examples of push-forward priors under Hölder continuous transformations that take advantage of the structure of inclusion detection problems. We show that the corresponding posterior mean converges to the ground truth in a proper probabilistic sense. Numerical tests on a two-dimensional quantitative photoacoustic tomography problem showcase the approach. The results highlight the convergence properties of the posterior distributions and the ability of the methodology to detect inclusions with sufficiently regular boundaries.
Effects of liquid properties on the development of nanosecond-pulsed plasma inside of liquid: comparison of water and liquid nitrogen
Authors: Song Zhiheng , Fridman Alexander , Dobrynin Danil
Published: February 2024

In this manuscript, we report on observations of the development of nanosecond-pulsed plasma in liquids and examine liquids with two drastically different properties: water and liquid nitrogen. Here, we compare the discharge appearance using high-speed imaging, examine bubble formation using shadow imaging, and measure the time-averaged optical emission spectra of these plasmas. Because the liquid nitrogen plasma is ignited in a liquid that is at boiling temperature, we also study the water discharge at various temperatures, up to boiling. We demonstrate that the discharge development appears not to be affected by this type of liquid. Optical emission, however, is strikingly different: in water, we observe continuum emission in the UV region only and no black-body continuum or atomic lines, whereas the liquid nitrogen spectrum is populated by molecular and longer wavelength broadband emissions.
Anisotropy constant of antiferromagnetic Pt50Mn50
Authors: Frost W , Carpenter R , Vallejo-Fernandez G
Published: February 2024

We have measured the anisotropy constant of polycrystalline PtMn thin films deposited on different seed layer materials: Pt, Ru and Nb. Values as high as

(
2.5
±
0.5
)
⋅

10

7

e
r
g

c
m

−
3

were achieved for samples deposited on Pt. The films can be crystallised into the antiferromagnetic, face-centred-tetragonal phase on Ru and Pt seed layers at annealing temperatures compatible with back-end-of-line conditions of up to 400 ∘C for one to three hours. Additionally these antiferromagnetic layers, 8 nm thick, are highly thermally stable with median blocking temperatures above 200 ∘C. The effect of diffusion on the stoichiometry of the PtMn layers is discussed with regards to the different seed layer materials.
On the role of defects in modelling approaches for thin film gas barrier coatings on polymer substrates: I. Model development
Authors: Franke J , Dahlmann R
Published: February 2024

We present a method to model the gas permeation through silicon-oxide thin film coatings that are afflicted with nanoscale defects. With it, we are able to give an estimation of the diffusion coefficient in bulk by subtracting the influence of the defects. The model is based on data obtained from positron annihilation spectroscopy, which is processed to yield possible defect allocation patterns of the coatings. For a systematic evaluation of these patterns, a path through the coating is calculated and then subjected to in-depth analysis to evaluate the used approach as well as to interpret the results for insights on the permeation mechanisms. The model appears to function as intended and no unexpected behaviour is observed. The defect volume share is overestimated, which can be retraced to the underlying algorithm, and a correction method is applied to the resulting bulk diffusion coefficient. The model gives reasonable results both for oxygen and water vapor permeation. These results can be used in following works that build on the presented model.
Graph attention neural networks for mapping materials and molecules beyond short-range interatomic correlations
Authors: Liu Yuanbin , Liu Xin , Cao Bingyang
Published: February 2024

Bringing advances in machine learning to chemical science is leading to a revolutionary change in the way of accelerating materials discovery and atomic-scale simulations. Currently, most successful machine learning schemes can be largely traced to the use of localized atomic environments in the structural representation of materials and molecules. However, this may undermine the reliability of machine learning models for mapping complex systems and describing long-range physical effects because of the lack of non-local correlations between atoms. To overcome such limitations, here we report a graph attention neural network as a unified framework to map materials and molecules into a generalizable and interpretable representation that combines local and non-local information of atomic environments from multiple scales. As an exemplary study, our model is applied to predict the electronic structure properties of metal-organic frameworks (MOFs) which have notable diversity in compositions and structures. The results show that our model achieves the state-of-the-art performance. The clustering analysis further demonstrates that our model enables high-level identification of MOFs with spatial and chemical resolution, which would facilitate the rational design of promising reticular materials. Furthermore, the application of our model in predicting the heat capacity of complex nanoporous materials, a critical property in a carbon capture process, showcases its versatility and accuracy in handling diverse physical properties beyond electronic structures.
The structural stability of Mn3Sn Heusler compound under high pressure
Authors: Zhang Junran , Lu Yunhao , Li Yanchun
Published: February 2024

Pressure engineering has attracted growing interest in the understanding of structural changes and structure-property relations of layered materials. In this study, we investigated the effect of pressure on the crystal structure of Mn3Sn. In-situ high-pressure x-ray diffraction experiments revealed that Mn3Sn maintained hexagonal lattice symmetry within the pressure range of ambient to 50.4 GPa. The ratio of lattice constants c/a is almost independent of the pressure and remains constant at 0.80, indicating a stable cell shape. Density functional theory calculations revealed the strong correlation between the crystal structure and the localization of d electrons. The Mn3Sn has been found in flat energy bands near the Fermi level, exhibiting a large density of states (DOS) primarily contributed by the d electrons. This large DOS near the Fermi level increases the energy barrier for a phase transition, making the transition from the hexagonal phase to the tetragonal phase challenging. Our results confirm the structural stability of Mn3Sn under high pressure, which is beneficial to the robustness of spintronic devices.
Investigating the impact of new dosimetric quantities recommended by ICRU 95 on the OSLD individual monitoring system at OAP, Thailand
Authors: Rindhatayathon P , Pungkun V
Published: February 2024

This research investigates the effects of new definitions of operational dosimetric quantities, especially H
p(10) to Hp recommended by ICRU Report 95, on the dosimetry system. This paper focuses on the responses of two dosimeter types, nanoDot® and InLight®, using conversional coefficients from ICRU report 57 and ICRU report 95 conversion coefficients. The dosimeters were irradiated with various beam qualities, and their responses were compared to the acceptant limits provided by the IEC 62387. The results demonstrate higher responses at new definitions recommended by ICRU report 95, indicating the need for algorithm modifications in the dose calculation.
Rapid, label-free, contactless measurement of membrane potential in excitable H9c2 cardiomyoblasts using ζ-potential
Authors: Chacar Stephanie , Catacutan Mary Krystelle , Albakr Shamma , Al Safar Habiba , Babiker Samira , Ahmed Samar , Albizreh Anas A , Alshehhi Ahmed Z , Lee Sungmun , Nader Moni , Hughes Michael Pycraft
Published: February 2024

The measurement of cell membrane potential (V
m) is important for understanding ion channel function. V
m plays a role in several routine cellular functions and diseases, particularly in excitable cells such as muscle and nerve. However, measuring V
m is difficult, relying either on labour-intensive direct measurement of single cells (intracellular electrodes, patch clamp) or indirect measurement of fluorescence intensity, using V
m-sensitive labels. Here we demonstrate a direct measurement technique based on determination of the cell’s ζ-potential, the electrical potential at the hydrodynamic shear plane, approximately 1 nm beyond the cell surface. We demonstrate this principle using excitable H9c2 cardiomyoblasts, measured in both polarised and depolarised states, before and after extracellular intervention to alter cell ion concentration. Given widespread availability of ζ-potential measurement apparatus (most typically in chemistry and materials science settings), this offers a new method of measuring V
m without the need for fluorescence measurements or calibration curves.
Robust distance measurement using illumination map estimation and MAHNet in underground coal mines
Authors: Zhang Jingjing , Li Jiacheng , Liu Haoting , Wang Honglei , Yi Dewei , Li Qing
Published: February 2024

An effective binocular stereo distance measurement method is proposed to address challenges posed by low brightness and weak texture of images captured in underground coal mines for the machine vision method. This approach is based on illumination map estimation and the MobileNetV3 attention hourglass stereo matching network (MAHNet) model. First, a binocular stereo vision system is established in which infrared LEDs are uniformly distributed on both sides of the belt conveyor bracket as visual feature points. Second, images are preprocessed using illumination map estimation, and the optimization of inhomogeneous brightness image enhancement is achieved by adopting adaptive Gamma correction. Third, the YOLOv5 target detection network and Gaussian fitting fusion algorithm are utilized to detect infrared LED feature points. Fourth, the MAHNet model is employed to generate the cost volume and perform disparity regression, resulting in the acquisition of accurate disparity images. Finally, triangulation is applied to determine the depth of feature points. The experimental results of distance measurement demonstrate that an average relative ranging accuracy of 1.52% within the range of 50.0 cm to 250.0 cm can be achieved by the optimized method, thereby validating the effectiveness of this binocular distance measurement method in underground coal mines.
Gas pipeline leakage detection and location by using w-FBG array based micro-strain sensing technology
Authors: Gan Weibing , Li Xiaolong , Wang Yu , Wulamu Ajiaikebaier , Zhang Cui , Chen Xianfeng
Published: February 2024

In addressing the significant security concerns associated with urban natural gas transportation, particularly the potential catastrophic consequences of leaks, this paper introduces a novel approach for detecting and locating leaks in natural gas pipelines using weak fiber Bragg grating (w-FBG) array micro-strain sensing technology. The field pipeline model is established, w-FBG array is applied to pipeline leakage experiment, and the pipeline leakage is detected by analyzing the change trend of micro-strain. The pipeline leakage experiments under different pressures were carried out. The experimental results show that there is a good linear relationship between the pipeline leakage pressure and the wavelength change of w-FBG, and the linearity is greater than 0.99, which is consistent with the theoretical analysis and verifies the applicability of w-FBG. According to the characteristics of micro-strain transfer in pipeline leakage process, a ‘abrupt change point’ capturing method based on peak to peak slope and threshold judgment is proposed. Results indicate that the proposed algorithm effectively detects pipeline leaks and accurately locates the point of leakage, with a positioning error of approximately 0.5 m. Compared with the traditional method, the proposed method has higher precision.
Material deformation mechanism of lamellar twined high–entropy alloys during machining
Authors: Vu Thi-Nhai , Pham Van-Trung , Fang Te-Hua
Published: February 2024

The effects of sample structure and tool geometry are studied under cutting simulation to verify the deformation, removal mechanisms, and subsurface defection of lamellar twined CoCuFeNiPd alloys. These findings suggest that the twin boundary spacing (TBS) and twin inclination angle (β) are the main determinants of surface wear characteristics and cutting-induced surface harm. The maximum cutting force achieved with TBS = 8a and β = 90°. The high friction coefficient with the sample has TBS = 8a and β = 90°, showing that the tool’s moving in the substrate is strongly restricted. Furthermore, the surface topography is not sensitive to the TBS and β. The best-machined surface is achieved with TBS = 3a and 4a under twin inclinations of 0° and 30°. The effect of edge radius (R), rake angle (γ), and clearance angle (α) on the deformation behavior is examined. The negative of γ, small α, or larger R results in a higher cutting force, a worse subsurface, and a lower cutting pile-up height. With a positive γ, a large α or small R has a larger average friction coefficient, which implies a higher resistance rate. The tool with a smaller R or positive γ can improve the machined surface’s smoothness.
Study on the atomic removal behavior and damage formation mechanism of nano cutting copper–nickel alloy with diamond tool
Authors: He Yan , Gao Zikai , Tang Meiling , Gao Xingjun , Fan Lin , Sun Jingting
Published: February 2024

The effects of tool rake angle and cutting depth on cutting temperature, cutting force, friction coefficient of rake tool face, atomic accumulation of chip flow and removal, surface quality, sub-surface damage layer thickness, atomic stress, and dislocation evolution were studied by molecular dynamics simulations. The results showed that the cutting temperature was concentrated on the chip, and the chip was easy to flow out with the increase of the tool rake angle, which weakens the extrusion and shearing action of the workpiece, resulting in the gradual reduction of tangential force. The tool rake angle of 10° is beneficial to improve the surface/subsurface quality of the workpiece. The minimum root-mean-square roughness obtained was 0.73 Å. The atomic stress of the workpiece was mainly concentrated around the area of interaction with the tool, and the atoms on the finished surface underwent elastic recovery, so the atomic stress was not significant. The 1/6<112> (Shockley) dislocation density had always been in the leading position, and 1/6<112> (Shockley) dislocation was continuously synthesized and decomposed during the nano-cutting process. With the increase of cutting depth, the number of atoms removed increases rapidly, and the width of chip side flow increases, but the symmetry is weakened. The contour line map even shows deep wave valleys caused by the absence of atoms, which increases the surface roughness. Moreover, the area and depth of the atomic stress distribution in the subsurface layer increase, and the number of amorphous atoms and dislocation density increase.
Unveiling the temperature-dependent thermoelectric properties of the undoped and Na-doped monolayer SnSe allotropes: a comparative study
Authors: Shi H L , Han Q Z , Yang J , Gong L J , Ren Y H , Zhao Y H , Yang H , Liu Q H , Jiang Z T
Published: February 2024

Motivated by the excellent thermoelectric (TE) performance of bulk SnSe, extensive attention has been drawn to the TE properties of the monolayer SnSe. To uncover the fundamental mechanism of manipulating the TE performance of the SnSe monolayer, we perform a systematic study on the TE properties of five monolayer SnSe allotropes such as α-, β-, γ-, δ-, and ε-SnSe based on the density functional theory and the non-equilibrium Green’s functions. By comparing the TE properties of the Na-doped SnSe allotropes with the undoped ones, the influences of the Na doping and the temperature on the TE properties are deeply investigated. It is shown that the figure of merit ZT will increase as the temperature increases, which is the same for almost all the Na-doped and undoped cases. The Na doping can enhance or suppress the ZT in different SnSe allotropes at different temperatures, implying the presence of the anomalous suppression of the ZT. The Na doping induced ZT suppression may be caused basically by the sharp decrease of the power factor and the weak decrease of the electronic thermal conductance, rather than by the decrease of the phononic thermal conductance. We hope this work will be able to enrich the understanding of the manipulation of TE properties by means of dimensions, structurization, doping, and temperature.
Atomic layer deposition of SnS2 film on a precursor pre-treated substrate
Authors: Kim Jungtae , Lee Dowwook , Bae Jangho , Lee Taeyoon , Jeon Hyeongtag
Published: February 2024

Two-dimensional (2D) materials are attracting attention because of their outstanding physical, chemical, and electrical properties for applications of various future devices such as back-end-of-line field effect transistor (BEOL FET). Among many 2D materials, tin disulfide (SnS2) material is advantageous for low temperature process due to low melting point that can be used for flexible devices and back-end-of-line (BEOL) devices that require low processing temperature. However, low temperature synthesis method has a poor crystallinity for applying to various semiconductor industries. Hence, many studies of improving crystallinity of tin disulfide film are studied for enhancing the quality of film. In this work, we propose a precursor multi-dosing method before deposition of SnS2. This precursor pre-treatment was conducted by atomic layer deposition cycles for more adsorption of precursors to the substrate before deposition. The film quality was analyzed by x-ray diffraction, Raman, transmission electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy. As a result, more adsorbates by precursor pre-treatment induce higher growth rate and better crystallinity of film.
Celiac disease diagnosis from endoscopic images based on multi-scale adaptive hybrid architecture model
Authors: Wang Yilei , Shi Tian , Gao Feng , Tian Shengwei , Yu Long
Published: February 2024

Objective. Celiac disease (CD) has emerged as a significant global public health concern, exhibiting an estimated worldwide prevalence of approximately 1%. However, existing research pertaining to domestic occurrences of CD is confined mainly to case reports and limited case analyses. Furthermore, there is a substantial population of undiagnosed patients in the Xinjiang region. This study endeavors to create a novel, high-performance, lightweight deep learning model utilizing endoscopic images from CD patients in Xinjiang as a dataset, with the intention of enhancing the accuracy of CD diagnosis. Approach. In this study, we propose a novel CNN-Transformer hybrid architecture for deep learning, tailored to the diagnosis of CD using endoscopic images. Within this architecture, a multi-scale spatial adaptive selective kernel convolution feature attention module demonstrates remarkable efficacy in diagnosing CD. Within this module, we dynamically capture salient features within the local channel feature map that correspond to distinct manifestations of endoscopic image lesions in the CD-affected areas such as the duodenal bulb, duodenal descending segment, and terminal ileum. This process serves to extract and fortify the spatial information specific to different lesions. This strategic approach facilitates not only the extraction of diverse lesion characteristics but also the attentive consideration of their spatial distribution. Additionally, we integrate the global representation of the feature map obtained from the Transformer with the locally extracted information via convolutional layers. This integration achieves a harmonious synergy that optimizes the diagnostic prowess of the model. Main results. Overall, the accuracy, specificity, F1-Score, and precision in the experimental results were 98.38%, 99.04%, 98.66% and 99.38%, respectively. Significance. This study introduces a deep learning network equipped with both global feature response and local feature extraction capabilities. This innovative architecture holds significant promise for the accurate diagnosis of CD by leveraging endoscopic images captured from diverse anatomical sites.
Properties and characteristics of the nanosecond discharge developing at the water–air interface: tracking evolution from a diffused streamer to a spark filament
Authors: Arora Garima , Hoffer Petr , Prukner Václav , Bílek Petr , Šimek Milan
Published: February 2024

The characteristics of nanosecond discharge propagating along the water–air interface in a unique dielectric-barrier discharge (DBD)-like configuration with coplanar electrodes submerged in deionised (DI)/tap water are studied by combining ultrafast imaging and emission spectra with electrical characteristics. Time-resolved images provide a clear signature of streamer channels excited on the water surface at either side of the blade (insulated plastic separating the anode/cathode) and propagating perpendicularly away from it towards the anode/cathode with different velocities. Later on, the streamer channels convert into a few discrete and bright discharge channels due to ionisation instability (spark phase). There is no distinctive dependence on water conductivity in the streamer phase, as the optical emission spectroscopy and images of discharges only showed an increase of the luminosity and no significant changes in morphology. However, in the spark phase, more numerous, brighter, and thicker filaments form in tap water. The time-resolved emission spectra reveal the dominance of the first and second positive system of

N
2

molecular bands in the streamer phase, followed by the appearance of atomic lines of hydrogen, nitrogen, and oxygen in the spark phase. The emission spectra are utilised to estimate several important parameters (gas temperature, reduced electric field (

E

/

N

), and electron density (

n

e

)). The streamer phase is characterised by a low gas temperature and a peak

E

/

N

amplitude between 700 and 850 Td. On the other hand, the subsequent spark phase is characterised by a gas temperature of ∼400/1100 K and a free electron density up to

n

e

∼

10

17

–1018 cm−3 in DI/tap water.
An experimental and computational study on the ignition process of a pulse modulated dual-RF capacitively coupled plasma operated at various low-frequency voltage amplitudes
Authors: Shi De-Hua , Wang Xiao-Kun , Liu Yong-Xin , Donkó Zoltán , Schulze Julian , Wang You-Nian
Published: February 2024

The ignition process of a pulse modulated capacitively coupled argon discharge driven simultaneously by two radio frequency voltages [12.5 MHz (high frequency) and 2.5 MHz (low frequency, LF)] is investigated by multifold experimental diagnostics and particle in cell / Monte Carlo collision simulations. In particular, (i) the effects of the LF voltage amplitude measured at the end of the pulse-on period,

V

L
,
e
n
d

, on the spatiotemporal distribution of the electron impact excitation rate determined by phase resolved optical emission spectroscopy, and (ii) the electrical parameters acquired by analyzing the measured waveforms of the plasma current and voltage, are studied. Computed electrical parameters and spatio-temporal excitation maps show a good qualitative agreement with the experimental results. Especially, various breakdown mechanisms are found at different

V

L
,
e
n
d

. At low values of

V

L
,
e
n
d

, the ‘RF-avalanche’ mode (volume process) dominates the electron multiplication process. By increasing

V

L
,
e
n
d

, the ionization caused by the volume electrons is suppressed and the electron loss at the electrodes is enhanced, leading to a delayed ignition. At higher values of

V

L
,
e
n
d

, the avalanche ionization is significantly enhanced by ion-induced secondary electron emission at the electrodes, so that the ignition is significantly advanced.
A metamaterial-assisted coda wave interferometry method with nonlinear guided waves for local incipient damage monitoring in complex structures
Authors: Shan Shengbo , Liu Ze , Zhang Chi , Cheng Li , Pan Yongdong
Published: February 2024

Nonlinear guided waves exhibit high sensitivity to material microstructural changes, thus attracting increasing attention for incipient damage monitoring applications. However, conventional nonlinear guided-wave-based methods suffer from two major deficiencies which hinder their applications: (1) mostly relying on the first arrivals of wave signals, they apply to limited inspection areas in simple structures in order to avoid wave reflections from structural discontinuities or boundaries; (2) they are prone to numerous deceptive nonlinear sources in the measurement system which might overwhelm damage-induced signal components. To tackle these challenges, we propose a metamaterial-assisted coda wave interferometry (CWI) method using second harmonic Lamb waves, applicable to the monitoring of local incipient damage in complex structures. Embracing the metamaterial concept, a so-called meta-screen is designed, whose geometry and layout can be flexibly tailored to target specific inspection zones in a structure. Capitalizing on its customized bandgap features, the proposed meta-screen allows for the passing of fundamental waves while preventing the second harmonic components generated by deceptive nonlinear sources from penetrating into the inspection area. Through numerical analyses on a plate with a rib stiffener, the efficacy of the meta-screen and the influence of occasional disturbance and regular pollution are evaluated. Experimental validations on an adhesive structure also confirm the superior sensitivity of the nonlinear coda waves to incipient damage, which is further enhanced by the deployment of the meta-screen alongside improved robustness against deceptive nonlinear sources outside the inspection area. The proposed metamaterial-assisted CWI method with second harmonic Lamb waves holds great promise for local incipient damage monitoring of complex structures.
Investigating forced vibration of an intelligent sandwich plate consisting of a metal foam core, stiff nanocomposite layers and active piezomagnetic face-sheets exposed to electro-magnetic potentials
Authors: Mirtabaei Seyed Mostafa , Farajollahi Amir Hamzeh , Pourseifi Mehdi
Published: February 2024

The main purpose of the present article is to present a forced vibrational analysis for a new intelligent sandwich plate made up of various layers. The proposed intelligent structure contains a porous metal foam core, super stiff double-FG nanocomposite layers, and piezomagnetic actuators which will be actuated magnetically and electrically. For the metal foam core of the structure, three kinds of porosity patterns are considered and, in the double-FG nanocomposite layers, Carbon Nanotubes (CNTS) are dispersed through various FG patterns in an FG metal-ceramic matrix. The power-law function is used to form the FG metal-ceramic matrix of the nanocomposite layers. Then, first-order shear deformation theory (FSDT) is utilized to derive the governing equations, and the resonance and natural frequencies of the proposed sandwich structure with simply-supported boundary conditions are obtained employing Navier’s analytical solution method. Finally, the effects of various parameters such as the CNTs’ volume fraction, magnetic and electric potentials, porosity patterns, core-to-nanocomposite layers thickness ratio, power-law index, etc on the resonance behavior of the structure will be discussed based on tabular and graphical results. The results demonstrate that the occurrence of the resonance phenomenon in such a multi-layered structure remarkably depends on the mentioned parameters and can be somehow controlled by applying magnetic and electric potentials to the piezomagnetic actuators connected to the top and bottom of the structure.
Recent advances in two-dimensional transition metal oxides and di-chalcogenides as efficient thermoelectric materials
Authors: Rani Rekha , Sinha M M
Published: February 2024

Designing of efficient thermoelectric material is the need of hour to avoid the adverse effect on environment. Two-dimensional (2D) transition metal oxides (TMOs) and transition metal dichalogenides (TMDCs) are receiving attention of researchers due to their wide range of electronic properties, high temperature and air stability, tunable electron transport properties for high thermoelectric efficiency (ZT). Two- dimensionalization in these materials lead to the increase in their thermoelectric efficiency as compared to their bulk counterpart due to the quantum confinement effect. These materials possess high thermoelectric efficiency even at high temperature (500–800 K) but their application still lagging behind commercially due to low ZT value. Various approaches such as strain engineering, defect engineering etc. Were adopted to further enhance the ZT value of these materials. Controlling chalcogen atomic defect provides an alternative avenue for engineering a wide range of physical and chemical properties of 2D TMOs/TMDCs. In this review we will systematically present the progress made in the study of electronic, phononic, transport properties and Seebeck coefficient of 2D TMOs/TMDCs such as XO2 (X=Cr, Mo, Zr) and MX2 (M= Cr, Mo, Zr; X= S, Se, Te) by using first principle approach. Methodologies such as strain engineering and doping to enhance the ZT values has also been discussed. In the last section we have discussed the experimental results of thermoelectric parameters of TMDCs and compare them with the existing theoretical results. It is concluded from this study that there are plenty of rooms which can be explored both theoretically and experimentally to design efficient thermoelectric materials for energy harvesting.
Theoretical investigations of the vibrational spectra and hydrogen bond vibrations of two-dimensional ice I
Authors: Liu Xiao-Yan , Liu Sicheng , Li Yi-Ning , Guo Qing , Yin Yi , Zhang Peng
Published: February 2024

In 2020, experimental observations of a stable two-dimensional (2D) ice I structure on a gold substrate were reported. As an atomic-level material, 2D ice has potential applications in many fields. However, the vibrational spectra of 2D ice I, including its infrared (IR) absorption, Raman scattering, and inelastic neutron-scattering spectra, have not been collected, owing to the complexity of the experimental conditions required to do so. We used first-principle density functional theory calculations to model 2D ice I and proved that it can stably exist without a gold substrate. We also simulated the vibrational phonon density of states and the IR and Raman spectra of 2D ice I. The vibrational frequencies in the translational band of 2D ice I were lower than those of 3D ice, owing to the hydrogen bonds of the former being weaker than those of the latter. The dynamic process analysis of hydrogen bonds showed that the vibrational modes of 2D ice I are quite different with that of 3D ice showing a different vibrational spectrum.
NAJADS: a self-contained framework for the direct determination of astrophysical J-factors
Authors: Balaudo Anna , Calore Francesca , De Romeri Valentina , Donato Fiorenza
Published: February 2024

Cosmological simulations play a pivotal role in understanding the properties of the dark matter (DM) distribution in both galactic and galaxy-cluster environments.
The characterization of DM structures is crucial for informing indirect DM searches, aiming at the detection of the annihilation (or decay) products of DM particles.
A fundamental quantity in these analyses is the astrophysical J-factor. In the DM phenomenology community, J-factors are typically computed through the semi-analytical modelling of the DM mass distribution, which is affected by large uncertainties.
With the scope of addressing and possibly reducing these uncertainties, we present NAJADS, a self-contained framework to derive the DM J-factor directly from the raw simulations data.
We show how this framework can be used to compute all-sky maps of the J-factor, automatically accounting for the complex 3D structure of the simulated halos and for the boosting of the signal due to the density fluctuations along the line of sight.
After validating our code, we present a proof-of-concept application of NAJADS to a realistic halo from the IllustrisTNG suite, and exploit it to make a thorough comparison between our numerical approach and traditional semi-analytical methods.
Flat-sky angular power spectra revisited
Authors: Gao Zucheng , Vlah Zvonimir , Challinor Anthony
Published: February 2024

We revisit the flat-sky approximation for evaluating the angular power spectra of
projected random fields by retaining information about the correlations along the line of
sight. For the case of projections with broad, overlapping radial window functions, these
line-of-sight correlations are suppressed and are ignored in the commonly adopted Limber
approximation. However, retaining the correlations is important for narrow window functions or
unequal-time spectra but introduces significant computational difficulties due to the highly
oscillatory nature of the integrands involved. We deal with the integral over line-of-sight
wave-modes in the flat-sky approximation analytically, using the FFTlog expansion of the 3D power
spectrum. This results in an efficient computational method, which is a substantial improvement
compared to any full-sky approaches. We apply our results to galaxy clustering (with and without
redshift-space distortions), CMB lensing and galaxy lensing observables in a flat
ΛCDM universe. In the case of galaxy clustering, we find excellent agreement with
the full-sky results on large (percent-level agreement) and intermediate or small (subpercent
agreement) scales, dramatically out-performing the Limber approximation for both wide and narrow
window functions, and in equal- and unequal-time cases. In the cases of lensing, we show on the
full-sky that the angular power spectrum of the lensing convergence can be very well approximated
by projecting the 3D Laplacian (rather than the correct angular Laplacian) of the gravitational
potential, even on large scales. Combining this approximation with our flat-sky techniques
provides an efficient and accurate evaluation of the CMB lensing angular power spectrum on all
scales. We further analyse the clustering and lensing angular power spectra by isolating the
projection effects due to the observable- and survey-specific window functions, separating them
from the effects due to integration along the line of sight and unequal-time mixing in the 3D
power spectrum. All of the angular power spectrum results presented in this paper are obtained
using a Python code implementation, which we make publicly available.
Gravitational Waves and gravitino mass in No-Scale Supergravity inflation with Polonyi term
Authors: Crispim Romão Miguel , King Stephen F.
Published: February 2024

We study a No-Scale supergravity inflation model which has a non-minimal deformation of the Kähler potential and a Wess-Zumino superpotential extended by the inclusion of a Polonyi mass term. The non-minimal structure of the Kähler potential is responsible for an inflexion point that can lead to the production of gravitational waves at late stages of inflation, while the Polonyi term breaks supersymmetry at the end of inflation, generating a non-vanishing gravitino mass. After a thorough parameter space scan, we identify promising points for gravitational wave production. We then study the resulting gravitational wave energy density for this set of points, and we observe that the gravitational waves should be observable in the next generation of both space-based and ground-based interferometers. Finally, we show how the presence of the Polonyi term can be used to further boost the gravitational wave energy density, which is correlated with the gravitino mass. The code used for the scan and the numerical analysis is provided at https://gitlab.com/miguel.romao/gw-and-m32-no-scale-inflation-polonyi.
Defying eternal inflation in warm inflation with a negative running
Authors: Montefalcone Gabriele , Ramos Rudnei O. , Vicente Gustavo S. , Freese Katherine
Published: February 2024

It was pointed out previously [1] that a
sufficiently negative running of the spectral index of curvature
perturbations from (ordinary i.e. cold) inflation is able to prevent eternal inflation from
ever occurring. Here, we reevaluate those original results, but in the
context of warm inflation, in which a substantial radiation component (produced by the inflaton) exists throughout the inflationary period.
We demonstrate that the same general
requirements
found in the context
of ordinary (cold) inflation also hold true in warm inflation; indeed an even tinier amount of negative running
is sufficient to prevent eternal inflation. This is particularly pertinent, as models featuring negative running are more generic in warm inflation scenarios.
Finally, the condition for the existence of eternal inflation in cold inflation — that the curvature perturbation amplitude exceed unity on superhorizon scales — becomes more restrictive in the case of warm inflation. The curvature perturbations must be even larger, i.e. even farther out on the potential, away from the part of the potential where observables, e.g. in the Cosmic Microwave Background, are produced.