bluuebunny/crossref_metadata_2025 huggingface dataset:
Web apps for profile fitting and power balance analysis at Wendelstein 7-X
Authors: Wappl M. , Bozhenkov S. A. , Beurskens M. N. A. , Bannmann S. , Kuczyński M. D. , Smith H. M. , Brunner K. J. , Ford O. P. , Fuchert G. , Knauer J. P. , Langenberg A. , Pablant N. A. , Pasch E. , Poloskei P. Zs. , Wolf R. C. ,   W7-X Team
Published: September 2024

Two novel web apps for W7-X are introduced: Profile Cooker and Power House. They are designed to streamline the workflow of profile fitting and power balance analysis while offering a graphical user interface that works in any common browser. This allows us to compile a comprehensive database of experimental power balance results. All fitting functions available in Profile Cooker are presented and compared on the basis of example profiles. The power balance equation assumed in Power House is established and its individual terms are discussed. The main focus of the power balance analysis is on the turbulent transport coefficients. A model for quick calculation of neutral beam power deposition based on experimental profiles is presented. Neoclassical root transition poses an issue for power balance analysis due to the uncertainty of the radial electric field. A global, neoclassical simulation with the code EUTERPE is performed for a set of experimental profiles to gain an understanding of the neoclassical root transition.
Research on icing model and calculation methods
Authors: Hu Yaping , Pan Jiheng , Liu Yong , Zhang Changxian , Jiang Yuetao , Zhu Jiangnan
Published: September 2024

Aircraft icing seriously threatens flight safety. This paper describes a modified shallow-water icing thermodynamic model that is applicable to unstructured grids and considers the effects of changes in water physical parameters and sublimation on icing. An icing calculation method enables the automatic determination of whether freezing occurs and the type of icing. An autonomous icing calculation program is developed to extract the geometric coordinates and mesh information of the icing surface and combine this information with the multiphase flow field of air-supercooled water droplets. The icing equations in the Godnov format are discretized to produce a large-scale sparse matrix that is solved iteratively using the biconjugate gradient stabilized method. The output includes parameter distributions for the ice thickness, water film thickness, and equilibrium temperature. Taking the National Advisory Committee for Aeronautic 0012 airfoil as the study object, the results of icing simulations are compared with experimental data from an ice wind tunnel and the ice shapes calculated by the FENSAP-ICE software. The results are found to be in good agreement with the experimental data, and the ice height errors at stagnation points are less than 15%. In the case of rime ice, single-horned ice shapes are simulated for both conventional and large supercooled droplets. For mixed ice and glaze ice, double-horned ice shapes are simulated for both droplet conditions. FENSAP-ICE fails to simulate the ice horns and produces large errors in ice thickness and ice range.
Large eddy simulation analysis of a model reactive tracer through spatial filtering
Authors: Legare S. , Stastna M.
Published: September 2024

Large eddy simulations (LES) provide a methodology for both analyzing and simulating multi-scale flows when the smallest scales of motion cannot be resolved. Within environmental flows there exist numerous biogeochemical processes involving tracers undergoing reactions. In this study, we perform an a posteriori LES analysis on a direct numerical simulation of an idealized model reactive tracer subjected to three-dimensional turbulence induced by a Rayleigh–Taylor instability. The governing equations, including an advection–diffusion–reaction equation for the reactive tracer, are filtered, and the resulting sub-filter-scale terms are expressed in terms of interactions between scales. The procedure is demonstrated for a generalized degree N polynomial reaction function. Various spectral filters are applied to the data and compared. The preferential choice is to use the widest filter possible with a smoothed cutoff. The sub-filter-scale reaction term that results from filtering the reaction function is considered for each of the filter choices. When using a particularly harsh filter, local balances are found for the resolved scale and cross-scale components of the sub-filter-scale reaction term. The same result is shown for the vertical sub-filter-scale flux for both a reactive and a passive tracer. The components of the sub-filter-scale reaction and vertical flux terms involving interactions at the sub-filter-scale do not show any evidence of local balances and are distributed around the fine turbulent structures in the flow. This suggests that parameterizations for the sub-filter-scale terms would benefit from considering event specific dynamics.
Unsteady aerodynamic flow control at low Reynolds numbers via internal acoustic excitation
Authors: Kiley Joshua , White Matthew , Narsipur Shreyas
Published: September 2024

Aerodynamic flow control using internal acoustic excitation holds promise as it combines the simplicity of passive flow control techniques (in terms of added weight and operational complexity) with the control authority of active flow control methods. While previous studies have analyzed the effects of acoustic excitation on steady-wing aerodynamics, the effect of excitation on the unsteady aerodynamics is not known, which is the aim of the current effort. Internally mounted speakers on a symmetric National Advisory Committee for Aeronautics (NACA) 0012 wing are used to excite the unsteady boundary layer at the wing's leading edge as it executes linear pitch motions ranging from quasi-steady (trailing-edge driven stall) to vortex-dominated (mixed leading- and trailing-edge driven stall) motions at freestream Reynolds numbers (Re) of 120 000 and 180 000. Experimental results show that, although acoustic excitation delays stall for quasi-steady motions, it enhances lift in the linear region and increases leading-edge vortex strength for vortex-dominated motions. The degree of change was observed to be a function of the excitation frequency, with lower frequencies (≤ 250 Hz) leading to an increase in aerodynamic efficiency and higher frequencies having a negligible effect. The current work establishes the effects of acoustic flow excitation in unsteady, low-Re wing aerodynamics and provides insights on the path forward to effectively implement the method for active flow control.
Experimental investigation on the gas pressure influence laws and mechanical mechanism of coal and gas outbursts
Authors: Meng Han , Yang Yuzhong , Guo Haijun , Hou Wei , Li Xinwang , An Fenghua , Zhang Rui , Chen Li , Rong Tenglong , Yang Daming , Cheng Lichao , Niu Yufen
Published: September 2024

With the increasing frequency and intensity of coal and gas outburst disasters under deep mining conditions, studying the outburst mechanism of occurrence has great significance for outbursts prevention and control. The evolution law of coal and gas outbursts under different gas pressure is proposed. The outbursts law is analyzed utilizing the self-developed simulation experiment system of coal and gas outbursts, and the simulation experiment is carried out under the gas pressure of 0.45, 0.8, and 1.5 MPa. In the experiment, the gas pressure drops curves, the relative intensity change, the interval distribution of coal powder, and the evolution of outburst hole and the migration rate of coal powder are analyzed. The results indicate that (1) the gas pressure detected by the No. 4 gas pressure sensor starts to drop first; (2) the gas pressure is positively proportional to the relative outburst intensity. When the gas pressure increases from 0.45 to 0.80 MPa and then to 1.5 MPa, the farthest outburst distance of coal powder increases from 10 to 15 m and then to 21 m, and the corresponding relative outburst intensity increases from 22.94% to 35.74% and then to 45.73%, respectively. (3) The average proportion of coal particles size less than 0.28 mm and larger than 1 mm under each corresponding outburst interval is 40.75% and 22.53%, respectively. Experimental results show that the gas pressure plays an essential role in the secondary crushing and pulverization of coal samples during the outburst process. (4) The throwing velocity of the pulverized coal is increased with the gas pressure near the outburst hole. When the gas pressure is 0.8 MPa, the throwing velocity of pulverized coal reaches the maximum value of 32.40 m/s. (5) The dimensional characteristics and the location initiation of the outburst hole are obtained. The results showed that the outburst process of coal is mainly in two failure forms: pulverization and spallation. The research results provide a theoretical basis and test data support for the prevention and control of coal and gas outburst disasters.
Single-shot polarization detection with a highly scattering system
Authors: Gong Haokai , Yang Xiaomin , Cai Yangjian , Zhao Qian
Published: September 2024

Polarization detection plays a significant role in optics. However, the current detection methods usually involve mechanically rotating components, multiple measurement steps, complicated optical design, and precise microfabrication process. To address this issue, we propose a single-shot method to detect the polarization state of light based on a highly scattering system, which is constituted by a spatial light modulator and a highly scattering medium. When the incident light beam shaped by a superimposed wavefront is incident on a highly scattering medium, the foci represented the six components at horizontal, vertical, diagonal, antidiagonal, right circularly polarized, and left circularly polarized directions will appear behind the highly scattering medium simultaneously. By measuring the intensities of these six foci, all the Stokes parameters can be extracted. Taking advantage of the measured Stokes parameters, the orientation angle of major axis, the ellipticity, and the handedness of the polarization ellipse of incident light beam can be determined. Various light beams with different polarization states are detected to demonstrate the viability of the method. The experimental results and theoretical values are in a good agreement. Compared to the existing methods, this approach is fast, free of complicated fabrication, and independent of mechanical movement. The proposed method is expected to promote the development of real-time and broadband polarimetry.
Interface modeling analysis using density functional theory in highly reliable Pt/HfO2/TaOx/Ta self-rectifying memristor
Authors: Ren Sheng-Guang , Mao Ge-Qi , Xue Yi-Bai , Zhang Yu , Sun Jia-Yi , Zuo Wen-Bin , Li Yi , Xue Kan-Hao , Miao Xiang-Shui
Published: September 2024

The self-rectifying memristor (SRM) is a promising device prototype for high-density three-dimensional (3D) integration and high-efficiency in-memory computing (IMC) by virtue of its ability to effectively suppress sneak current, simple device structure, and low energy consumption. Theoretically understanding the intrinsic mechanisms of SRM is a matter of concern. Here, we fabricated a Ta/TaOx/HfO2/Pt-stacked SRM exhibiting >103 on/off ratio, rectification ratio, and nonlinearity. The SRM can be repeatedly programmed by more than 106 pulses and demonstrates robust retention and high scalability (∼59 Mbit). A reasonable interface model for this SRM is established based on first-principles calculations. Using self-energy corrected density function theory, we calculate the barrier heights at each interface. Detailed I–V curve fitting and energy band analysis are performed and computationally verified to explain the intrinsic reasons for resistive switching, self-rectifying, and nonlinear behaviors. The work may advance the development of SRM prototype to enable energy-efficient 3D IMC.
Numerical simulation of manta ray swimming using a smoothed-particle hydrodynamics method and investigation of the vortical structures in the wake
Authors: Gao Tian-Yu , Sun Peng-Nan , Huang Xiao-Ting , Zhao Jiao-Long , Xu Yang , Zhong Shi-Yun
Published: September 2024

A three-dimensional smoothed-particle hydrodynamics (SPH) method is used to study the moving boundary problem of a swimming manta ray, focusing on Eulerian and Lagrangian coherent structures. The manta ray's boundary motion is predefined by a specific equation. The calculated hydrodynamic results and Eulerian coherent structures are compared with data from the literature. To improve computational stability and efficiency, the δ+-SPH model used in this study incorporates tensile instability control and an improved adaptive particle-refinement technique. By comparing and analyzing the Eulerian and Lagrangian coherent structures, the relationship between these vortex structures and hydrodynamic force generation is examined, revealing the jet mechanism in the manta ray's wake. The SPH method presented herein is robust and efficient for calculating biomimetic propulsion problems involving moving boundaries with large deformations, and it can accurately identify vortex structures. The approach of this study provides an effective simulation tool for investigating biomimetic propulsion problems such as bird flight and fish swimming.
Experimental study on flow field and performance of bionic-wavy leading edge in an axial compressor with positive bowed blades
Authors: Zheng Longye , Zeng Cong , Chen Shaowen
Published: September 2024

To enhance the aerodynamic performance of compressors in advanced aeroengines, a compound flow control method combining positively bowed blades and bionic-wavy leading edges is proposed for improving the aerodynamic performance of compressor cascades with controlled diffusion airfoils. This study verified the effectiveness of the compound control method through low-speed wind tunnel experiments using five-hole probe measurements and surface oil-flow visualization techniques. Additionally, the flow field structure was analyzed, and vortex models were established to thoroughly discuss the mechanism of the compound flow control method. The results show that within the incidence angle range of 0°–4° studied in this paper, the composite control method achieved significantly effective control, with a maximum reduction in overall total pressure loss of 25.8% compared to straight blade cascades. Three vortex models were established. The positive bowed blade cascade induced a complex vortex structure in the concentrated shedding vortex region, increasing losses in the concentrated shedding vortex (CSV) region but reducing profile losses. The coupled method further reduced profile losses and optimized the flow field in the CSV region. This study not only validates the feasibility of the compound method but also provides guidance for applying flow control methods to bowed blade cascades.
Numerical simulation of He atmospheric pressure plasma jet impinging on the tilted dielectric surface
Authors: Wang Lijun , Zhao Huan , Han Zhongji , Liu Jie
Published: September 2024

The target surface to be treated in reality is often not smooth and horizontal and may also be in different tilting angles. The treatment of the tilted dielectric surface by the atmospheric pressure plasma jet (APPJ) undoubtedly increases the complexity of surface modification. Therefore, a two-dimensional fluid model is established to reveal the internal mechanism of the interaction between the He APPJ and the tilted dielectric surface by means of numerical simulation. The distribution of the gas flow in a small angular range (0°, 3°, 5°, 8°, 10°, and 15°) is studied. In addition, the effects of the tilt angle on the jet morphology, discharge dynamic properties, and species distribution of the He APPJ are emphatically discussed. It is found that the jet morphology and parameters are no longer symmetrical under the tilted surface. With the increase in the tilt angle, the enhanced electric field in the upper surface region leads to the increase in the ionization rate and electron density here, and also accelerates the propagation speed of the jet to the dielectric surface in the atmospheric environment. Driven by the electric field force, the jet is closer to the dielectric surface, resulting in a decrease in the thickness of the cathode sheath and an increase in the surface charge density in the area to the right of the central axis. The influence of the gas flow structure leads to the shortening of the jet development distance and a decrease in the jet velocity on the upper surface. N and O also form higher fluxes on the upper surface due to the increase in the electron density.
Energy harvesting and human motion sensing of a 2D piezoelectric hybrid organic–inorganic perovskite
Authors: Ji Li-Jun , Zhao Chen , Yang Tian-Yi , Yang Hai-Run , Azeem Muhammad , Li Zi-Ying , Feng Rui , Feng Guo-Qiang , Li Sha , Li Wei
Published: September 2024

Two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs) have garnered plentiful attention as a result of their exceptional structural flexibility and multiple applications. In this study, we present a 2D HOIP (CHA)2PbBr4 (CHA = cyclohexylamine), for its potential applications in piezoelectricity, such as strain energy sensing and harvesting. Flexible composite films of (CHA)2PbBr4/PDMS (PDMS = polydimethylsiloxane) with a sequence of weight ratios (0, 5, 10, 15, 20 wt %) of (CHA)2PbBr4 were fabricated to analyze the energy harvesting properties. Experimental results demonstrated that a device with 15% composition exhibited the most optimized performance in energy harvesting, producing a peak magnitude of output voltage of 11.6 V, a short-circuit current of 0.38 µA, and a power density of 6.77 µW/cm2, along with notable stability exceeding 4000 cycles. Furthermore, this device exhibited high sensitivity in monitoring many varieties of human movements, such as finger bending and tapping, elbow bending, and gentle foot stamping. The findings of this study indicate that this 2D HOIP holds significant potential for use in flexible sensing and intelligent wearable devices.
Codesigning a Community Health Navigator program to assist patients to transition from hospital to community
Authors: Harris Mark F. , Tran An , Porwal Mamta , Aslani Parisa , Cullen John , Brown Anthony , Harris Elizabeth , Harris-Roxas Ben , Doolan-Noble Fiona , Javanparast Sara , Wright Michael , Osborne Richard , Osten Regina
Published: September 2024

Background This study aimed to identify the potential roles for Community Health Navigators (CHNs) in addressing problems faced by patients on discharge from hospital to the community, and attitudes and factors which may influence their adoption. Methods Twenty-six qualitative interviews and an online codesign workshop were conducted with patients, nurses, general practice staff, health service managers, community health workers, general practitioners, medical specialists, and pharmacists in the Sydney Local Health District. Qualitative themes from the interviews and workshop transcripts were analysed inductively and subsequently grouped according to a socio-ecological model. Results CHNs could assist patients to navigate non-clinical problems experienced by patients on discharge through assessing needs, establishing trust, providing social and emotional support that is culturally and linguistically appropriate, engaging family and carers, supporting medication adherence, and helping to arrange and attend follow up health and other appointments. Important factors for the success of the CHNs in the performance and sustainability of their roles were the need to establish effective communication and trust with other healthcare team members, be accepted by patients, have access to information about referral and support services, receive formal recognition of their training and experience, and be supported by appropriate supervision. Conclusions This study was unique in exploring the potential role of CHNs in addressing problems faced by patients on discharge from Australian hospitals and the factors influencing their adoption. It informed training and supervision needs and further research to evaluate CHNs’ effectiveness and the acceptance of their role within the healthcare team.
Meandering conduction channels and the tunable nature of quantized charge transport
Authors: Douçot Benoit , Kovrizhin Dmitry , Moessner Roderich
Published: September 2024

The discovery of the quantum Hall effect has established the foundation of the field of topological condensed matter physics. An amazingly accurate quantization of the Hall conductance, now enshrined in quantum metrology, is stable against any reasonable perturbation due to its topological protection. Conversely, the latter implies a form of censorship by concealing any local information from the observer. The spatial distribution of the current in a quantum Hall system is such a piece of information, which, thanks to spectacular recent advances, has now become accessible to experimental probes. It is an old question whether the original and intuitively compelling theoretical picture of the current, flowing in a narrow channel along the sample edge, is the physically correct one. Motivated by recent experiments
locally
imaging quantized current in a Chern insulator (Bi, Sb)

2

Te

3

heterostructure [Rosen et al.,
Phys. Rev. Lett.
129
, 246602 (2022); Ferguson et al.,
Nat. Mater.
22
, 1100–1105 (2023)], we theoretically demonstrate the possibility of a broad “edge state” generically meandering away from the sample boundary deep into the bulk. Further, we show that by varying experimental parameters one can continuously tune between the regimes with narrow edge states and meandering channels, all the way to the charge transport occurring primarily within the bulk. This accounts for various features observed in, and differing between, experiments. Overall, our findings underscore the robustness of topological condensed matter physics, but also unveil the phenomenological richness, hidden until recently by the topological censorship—most of which, we believe, remains to be discovered.
Interleukin-33–activated basophils promote asthma by regulating Th2 cell entry into lung tissue
Authors: Schuijs Martijn J. , Brenis Gomez Claudia M. , Bick Fabian , Van Moorleghem Justine , Vanheerswynghels Manon , van Loo Geert , Beyaert Rudi , Voehringer David , Locksley Richard M. , Hammad Hamida , Lambrecht Bart N.
Published: September 2024

Asthma is characterized by lung eosinophilia, remodeling, and mucus plugging, controlled by adaptive Th2 effector cells secreting IL-4, IL-5, and IL-13. Inhaled house dust mite (HDM) causes the release of barrier epithelial cytokines that activate various innate immune cells like DCs and basophils that can promote Th2 adaptive immunity directly or indirectly. Here, we show that basophils play a crucial role in the development of type 2 immunity and eosinophilic inflammation, mucus production, and bronchial hyperreactivity in response to HDM inhalation in C57Bl/6 mice. Interestingly, conditional depletion of basophils during sensitization did not reduce Th2 priming or asthma inception, whereas depletion during allergen challenge did. During the challenge of sensitized mice, basophil-intrinsic IL-33/ST2 signaling, and not FcεRI engagement, promoted basophil IL-4 production and subsequent Th2 cell recruitment to the lungs via vascular integrin expression. Basophil-intrinsic loss of the ubiquitin modifying molecule Tnfaip3, involved in dampening IL-33 signaling, enhanced key asthma features. Thus, IL-33–activated basophils are gatekeepers that boost allergic airway inflammation by controlling Th2 tissue entry.
SMARCA5-mediated chromatin remodeling is required for germinal center formation
Authors: Stoler-Barak Liat , Schmiedel Dominik , Sarusi-Portuguez Avital , Rogel Adi , Blecher-Gonen Ronnie , Haimon Zhana , Stopka Tomas , Shulman Ziv
Published: September 2024

The establishment of long-lasting immunity against pathogens is facilitated by the germinal center (GC) reaction, during which B cells increase their antibody affinity and differentiate into antibody-secreting cells (ASC) and memory cells. These events involve modifications in chromatin packaging that orchestrate the profound restructuring of gene expression networks that determine cell fate. While several chromatin remodelers were implicated in lymphocyte functions, less is known about SMARCA5. Here, using ribosomal pull-down for analyzing translated genes in GC B cells, coupled with functional experiments in mice, we identified SMARCA5 as a key chromatin remodeler in B cells. While the naive B cell compartment remained unaffected following conditional depletion of Smarca5, effective proliferation during B cell activation, immunoglobulin class switching, and as a result GC formation and ASC differentiation were impaired. Single-cell multiomic sequencing analyses revealed that SMARCA5 is crucial for facilitating the transcriptional modifications and genomic accessibility of genes that support B cell activation and differentiation. These findings offer novel insights into the functions of SMARCA5, which can be targeted in various human pathologies.
Online decoupling of the time-varying longitudinal feedback loops for improved performance in Advanced Virgo Plus*
Authors: van Dael Mathyn , Witvoet Gert , Swinkels Bas , Pinto Manuel , Bersanetti Diego , Casanueva Julia , Ruggi Paolo , Mantovani Maddalena , Spinicelli Piernicola , de Rossi Camilla , Boldrini Mattia , Oomen Tom
Published: September 2024

Gravitational Wave detectors require low-noise sensors combined with high-performance feedback loops to maximize the detector sensitivity in the low-frequency detection range. Some feedback loops in the detector are strongly coupled and their coupling varies over time, which is inherent to the optical configuration and the optical readout scheme used to obtain error signals for the feedback loops. This paper presents a control-based approach to deal with the time-varying interaction among three of the longitudinal degrees of freedom in the Advanced Virgo Plus detector, using the pre-existing infrastructure of the detector. An intuitive Multiple-Input Multiple-Output stability criterion is presented that illustrates how the time-varying coupling affects the stability of the feedback loops, as well as a method that identifies the coupling online and updates a decoupling matrix accordingly. Experiment results of the proposed method on the Advanced Virgo Plus detector illustrate continuous minimization of the coupling over time. Using the derived stability criterion, it is furthermore shown that the coupling is sufficiently minimized such that the interaction terms can be neglected in the control design, resulting in an improved controller performance.
Finiteness of 3D higher spin gravity Landscape
Authors: Sammani Rajae , Boujakhrout Youssra , Saidi El Hassan , Ahl Laamara Rachid , Drissi Lalla Btissam
Published: September 2024

We give Swampland constraints on the three dimensional Landscape of Anti-de Sitter higher spin gravity in the Chern–Simons formulation with connection valued in various split real forms of Lie algebras. We derive the finiteness conjecture by computing the upper bound on the rank of possible gauge groups then we refine it using the AdS distance conjecture. We discuss the implications of this Swampland constraint on the spectrum of higher spin gravity theories and we compare it with the gravitational exclusion principle required from BTZ black hole consideration to excerpt a constraint on the Chern–Simons level k.
Amplified squeezed states: analyzing loss and phase noise
Authors: Kwan K M , Yap M J , Qin J , Gould D W , Chua S S Y , Junker J , Adya V B , McRae T G , Slagmolen B J J , McClelland D E
Published: September 2024

Phase-sensitive amplification of squeezed states is a technique to mitigate high detection loss, which is especially attractive at 2 µm wavelengths. We derived an analytical model proving that amplified squeezed states can mitigate phase noise significantly. Our model discloses two practical parameters: the effective measurable squeezing and the effective detection efficiency of amplified squeezed states. A realistic case study includes the dynamics of the gain-dependent impedance matching conditions of the amplifier. Our results recommend operating the optical parametric amplifier at high gains because of the signal-to-noise ratio’s robustness to phase noise. Amplified squeezed states are relevant in proposed gravitational wave detectors and interesting for applications in quantum systems degraded by the output coupling loss in optical waveguides.
Symmetries in particle physics: from nuclear isospin to the quark model
Authors: Berganholi Bruno , Dorsch Gláuber C , Sena Beatriz M D , do Valle Giovanna F
Published: September 2024

We present a concise pedagogic introduction to group representation theory motivated by the historical developments surrounding the advent of the Eightfold Way. Abstract definitions of groups and representations are avoided in favour of the physical intuition of symmetries of the nuclear interaction. The concept of nuclear isospin is used as a physical motivation to introduce SU(2) and discuss the main techniques of representation theory. The discovery of strange particles motivates extending the symmetry group to SU(3), at first in the context of the Sakata model. We highlight the successes in fitting mesons in the SU(3) octet, discuss the drawbacks of the Sakata model for baryonic classifications, and how the Eightfold Way finally led to the quark model. This approach has two major advantages: (i) the main concepts of the theory of Lie groups are introduced and discussed without ever losing touch with its applications in particle physics; (ii) it allows the beginner to study group theory while also becoming acquainted with the historical developments of particle physics that led to the concept of quarks. In particular, in this pedagogical path the quarks appear as yet another class of particles predicted from symmetry principles, rather than being introduced ad hoc for postulating an SU(3) symmetry, as usually done in the literature.
Far field operator splitting and completion in inverse medium scattering
Authors: Griesmaier Roland , Schätzle Lisa
Published: September 2024

We study scattering of time-harmonic plane waves by compactly supported inhomogeneous objects in a homogeneous background medium. The far field operator associated to a fixed scatterer describes multi-static remote observations of scattered fields corresponding to arbitrary superpositions of plane wave incident fields at a single frequency. In this work we consider far field operators for systems of two well-separated scattering objects, and we discuss the nonlinear inverse problem to recover the far field operators associated to each of these two scatterers individually. This is closely related to the question whether the two components of the scatterer can be distinguished by means of inverse medium scattering in a stable way. We also study the restoration of missing or inaccurate components of an observed far field operator and comment on the benefits of far field operator splitting in this context. Both problems are ill-posed without further assumptions, but we give sufficient conditions on the diameter of the supports of the scatterers, the distance between them, and the size of the missing or corrupted data component to guarantee stable recovery whenever sufficient a priori information on the location of the unknown scatterers is available. We provide algorithms, error estimates, a stability analysis, and we demonstrate our theoretical predictions by numerical examples.
Microstructural evolution and formation of defect complexes in diamond films by nitrogen-containing plasma
Authors: Raj Rahul , Chatterjee Subhajit , Pradeep K G , Ramachandra Rao M S
Published: September 2024

The morphology and crystalline quality of polycrystalline diamond samples were studied by systematically varying the flowrate of nitrogen gas in the microwave plasma. A slight improvement in both crystallite size and crystalline quality is observed for a low concentration of 0.5 sccm nitrogen. With a further increase in nitrogen concentration, diamond switches from micro-crystalline to nanocrystalline (NCD) with a nitrogen flow of 2.5 sccm (10% of methane concentration). The surface roughness of the sample is found to depend strongly on the crystallite size of the sample. Extensive spectroscopic studies have been done to understand the presence and formation of different defect complexes in diamond. XPS and Raman analysis of the films reveal the variation of graphitic content as a function of nitrogen addition. The presence of nitrogen-containing defect complexes has been studied thoroughly and their concentration has been found to be limited by the solubility limit rather than the availability of reactants in the gas environment. In contrast, the effect these complexes have on the strain of the diamond film is found to be negligible. Optical emission spectroscopy of the plasma reveals the presence of C2 dimers as well as C-N radicals. However, they have little role in modifying diamond grain morphology or crystalline quality.
Study on the vibration characteristics of angular contact ball bearing cage under rolling-sliding compound motion
Authors: Yang Fang , Xia Zhongbing , Ma Xiqiang , Guo Nan , Zhong Zhidan , Ye Jun
Published: September 2024

Cage fracture has become the main form of bearing failure, the study of factors affecting the operating condition of the cage has an important impact on the operating performance and life of bearings. This study takes the angular contact ball bearing H7006C as the object of study and extracts the bearing inner ring and cage speed to analyse the bearing slip rate law. Extract cage vibration data and analyse cage vibration frequency characteristics using the variational mode decomposition method. The effects of load and speed induced bearing slippage on the vibration characteristics of cages are investigated by varying the induced bearing slippage factors. The effects of load and speed induced bearing slip on the vibration characteristics of cages are investigated separately by varying the induced bearing slip factors. The study found that, at a fixed rotational speed, the bearing slip rate decreases as the axial load increases from 0 to 350 N, and then stabilizes beyond 350 N. Under fixed load conditions, the bearing slip rate increases with the rotational speed ranging from 1000 to 9000 rpm. At a constant speed, the axial load is varied within 50–100 N, resulting in vibration frequency increases of 72 Hz, 43.5 Hz, and 24 Hz at 1000 rpm, 5000 rpm, and 9000 rpm, respectively. The characteristic frequency of cage vibration rises with increasing load, contributing to smoother cage operation. Nonetheless, as the rotational speed increases, the influence of axial load-induced slippage on the vibration characteristics of the cage diminishes gradually. At a set load of 500 N, the amplitudes of the cage vibration eigenfrequencies at 1000 rpm, 3000 rpm, and 7000 rpm are 0.0317, 0.0288, and 0.0174, respectively, decreasing with rotational speed. This indicates that the cage does not operate smoothly. The findings of this study serve as a theoretical foundation for detecting and diagnosing bearing slip and vibration issues in rotating machinery.
A simulation study on visual preview control of vehicle magnetorheological suspension
Authors: Xie Lei , Wang Pengsai , Zhou Wei , Liao Changrong
Published: September 2024

At present, the boom in intelligent vehicles, especially automotives, has brought magnetorheological (MR hereinafter) suspensions into further focus. Generally, traditional MR suspensions work with acceleration sensors to respond with a non-negligible time delay issue due to the inductive property of MR damper (MRD hereinafter), which hinders their full performance especially at high-speed driving with a powerless ‘blind zone’. To address this issue, this study proposes a simulation study on visual preview control for vehicle MR suspension based on model predictive control, since the road preview is able to compensate the time delay due to the future road information perceived in advance. First, a camera with a computer vision algorithm is employed to preview road information of target type, target size and distance to wheels. Besides, the error correction of radial and tangential distortions of camera lens are investigated, and the trajectory of wheels are predicted by a cycloid model because MR suspension only needs to respond to the road targets that the wheels will pass over. Further, the area in front of the vehicle is divided into a recognition zone and action zone, and the road targets within action zone (<1.5 m) are calculated more precisely for a prepared immediate response from the MR suspension. Then, the performance of a simulating vehicle MR suspension is investigated through a joint simulation by the automotive simulation software CarSim and the model-solving Simulink. The evident results show that the MR suspension with visual preview control performs the best in ride comfort (mean square values of sprung mass acceleration is 82% and 52% lower compared to a passive suspension and a MR suspension with skyhook control, respectively). Therefore, the visual preview control strategy of MR suspension is able to enhance the performance on the discrete road conditions.
CORC® wires allowing bending to 20 mm radius with 97.5% retention in critical current and having an engineering current density of 530 A mm−2 at 20 T
Authors: van der Laan Danko , Weiss Jeremy , Radcliff Kyle , Abraimov Dmytro
Published: September 2024

Low-inductance, high-field insert solenoid magnets and 20 T dipole magnets for particle accelerators require flexible cables, wound from high-temperature superconductors (HTS) such as RE-Ba2Cu3O7−
δ (REBCO) coated conductors, that allow bending to a 20 mm radius without significant degradation in performance. They require an operating current of at least 5 kA and a high engineering current density (J
e) exceeding 500 A mm−2 at 20 T. HTS cable technologies that target such demanding magnet applications so far have not been able to meet the combination of these requirements. Here we present the development of the next generation of Conductor on Round Core (CORC®) wires that are produced with an optimized manufacturing process that improves their bending flexibility by factor of more than 2 compared to previous generation CORC® wires. CORC® wires now allow for a bending radius of 20 mm with only 2%–3% performance degradation. They allow bending to a radius of 15 mm with a performance retention of 83.5%. The performance of 30-tape CORC® wires wound from 2 mm wide REBCO tapes from SuperPower Inc, SuperOx and shanghai superconductor technologies was measured at magnetic fields up to 12 T. The overall performance at high magnetic fields of the next generation of CORC® wires improved by a factor of 1.5–1.8, depending on the REBCO tape manufacturer. CORC® wires wound from production REBCO tapes achieved a new record J
e of 751 A mm−2 at a current of 8.3 kA at 12 T, and a J
e of 530 A mm−2 at a current of 5.8 kA when extrapolated to 20 T. The next generation of CORC® wires present the first HTS cable technology that simultaneously meet the requirements on bending flexibility, engineering current density and critical current at 20 T for use in low-inductance, high-field particle accelerator magnets. They now enable a more expedited development of prototype low-inductance solenoid magnets that target fields exceeding 25 T and of accelerator magnets that generate a dipole field exceeding 20 T.
Dark current in FTO/CZTS interface: a comprehensive comparison of practical Vs theoretical approach using SCAPS-1D
Authors: Chavan Kalyan B , Desarada Sachin V , Chaure Shweta , Chaure Nandu B
Published: September 2024

This study investigates the deposition of Cu2ZnSnS4 (CZTS) thin films on fluorine-doped tin oxide (FTO) and soda-lime glass (SLG) substrates using radio frequency (RF) sputtering at varying temperatures. A comprehensive characterization employing multiple analytical techniques was conducted. X-ray diffraction (XRD) analyses confirmed the amorphous nature of CZTS films being deposited up to 200 °C, while higher temperatures promoted increased crystallinity, with the presence of (112) and (220) planes observed at 300 °C and 400 °C. Rietveld refinement using Profex software revealed an increase in crystallite size with deposition temperature for films grown at 300 °C and 400 °C. Optical characterization through UV–vis spectroscopy unveiled a decrease in band gap energy with increasing deposition temperature, while the Urbach energy, associated with defects and imperfections, exhibited an inverse relationship with band gap and temperature. Experimental current–voltage (I-V) measurements using a Keithley source meter showed variations in the ideality factor with deposition temperature. SCAPS-1D simulations were performed to model the FTO/CZTS interface, incorporating experimental parameters. The simulated I-V behavior demonstrated a transition from recombination to diffusion-dominated current above 1.3 V forward bias. Simulations yielded higher ideality factors due to increased contributions from recombination and diffusion currents. Overall, this study provides insights into the growth, structural, optical, and electrical properties of CZTS thin films deposited by RF sputtering, enabling a comprehensive understanding of the FTO/CZTS heterojunction characteristics and their dependence on deposition temperature.
Wavelength tunable single-frequency ring cavity fiber laser utilizing external injection locking signal
Authors: Chen Xuening , Tian Chuan , Wang Meng , Bai Xiaolei
Published: September 2024

The ring cavity fiber laser with saturable absorption fibers is a simple and practical technical way of achieving single-frequency laser output. However, this structure cannot obtain wavelength-tunable laser output. In this work, an external injection locking signal launched by tunable LD is used to optimize the tunability in single-frequency ring cavity fiber lasers. By aligning the external injection signal, tunable laser output ranging from 1544.13 to 1546.51 nm is achieved. The maximum output is 16.5 mW and the linewidth is less than 6.15 kHz. The operation process and the linewidth compression effect of external Injection signals are investigated. The results indicate that there is a correlation between the output signal-to-noise ratio and the output linewidth, and this wavelength-tuning structure has the potential for rapid tuning. This work provides a technical solution for achieving a tunable single-frequency laser in the ring cavity structure.
Barrow holographic dark energy: reconstruction within Saez-Ballester theory in Kantowski-Sachs universe
Authors: Chokyi Khandro K , Chattopadhyay Surajit , Tawfik Abdel Nasser
Published: September 2024

Within the framework of the Saez-Ballester theory, the Barrow Holographic Dark Energy (BHDE) has been reconstructed. This reconstruction was carried out in a homogeneous and anisotropic KS universe that was filled with BHDE. The study examined both non-interacting and interacting scenarios, with the future event horizon serving as the IR cut-off. The analysis focused on the evolution of the equation of State parameter for both cases, as well as the trajectories of

w

DE

−
w

′

DE

. Additionally, the study investigated the inflation of the Universe filled with BHDE by plotting the slow-roll parameters. Furthermore, a connection between the canonical scalar field and BHDE was explored, as the presence of a scalar field is often associated with inflation. Finally, the tensor-to-scalar ratio r is plotted which seems to lie within the acceptable range.
Water-based metamaterial absorber for temperature modulation
Authors: Yang Hongqin , Zhang Jing , Shen Zhaoyang
Published: September 2024

In this study, a transmissive all-dielectric metamaterial absorber comprising a photosensitive resin and water layers was proposed. The water layers comprised coin rings, crosses, and fan shapes. The as-obtained absorber achieved >90% absorption of electromagnetic waves within the frequency range of 18.4–41.7 GHz, and the absorption bandwidth covered the Ka-band. Because of the symmetric structure of the designed metamaterial, it was not influenced by polarization. The inherent dispersive properties of water result in a dielectric constant that varies significantly with temperature. This led to fluctuations in the absorption efficiency of the designed metamaterial to different degrees with changes in temperature. The analysis of electric and magnetic fields distributions revealed that the primary absorption physical mechanism of the designed metamaterial originated from magnetic resonances in the water layers. The proposed transmissive metamaterial absorber has potential applications in high-sensitivity thermal and temperature sensors.
Enhancing the security of image communication with a new hyper-chaotic system
Authors: Deshpande Amey S , Daftardar-Gejji Varsha
Published: September 2024

The rapid expansion of multimedia communication necessitates the development of advanced and resilient cryptographic systems. As computational power grows, traditional encryption methods become susceptible to brute-force attacks. Cybersecurity threats are in a constant state of flux, requiring the creation of innovative cryptographic systems to outpace these developments. Chaotic systems offer a very good promise in cryptography as they are sensitive to initial conditions and parameters. In this study, the authors propose a novel hypercryptographic system (referred as NHCS) for color images that integrates a new hyperchaotic system with the RSA algorithm. This approach combines the unpredictable behavior of the hyper-chaotic system with the robust encryption capabilities of the RSA algorithm. This combination provides an additional layer of security. The hyper-chaotic systems offer a broader range of parameter values leading to chaos. Moreover, due to their four-dimensional nature, they can be employed to encrypt four-color channels. The NHCS algorithm has a large key space (of size 2704), 1024-bit RSA encrypted for higher security. The key sensitivity of this algorithm is of the order 10−16. The effectiveness of NHCS is validated through numerous test images from the USC-SIPI database and is bolstered by statistical analysis. The two indicators NPCR (∽100% ) and UACI (>33%) ensure that the system is robust against differential attacks. We perform a correlation analysis of the images and observe that correlation coefficients between adjacent pixels of the encrypted images are close to zero. Further, the information entropy values of the encrypted images are close to the ideal value 8. PSNR, MSE, and other statistical measures are found near their respective ideal values. A comparison with the other methods shows that NHCS is very promising.