bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of gap ratios on wake dynamics of two rectangular 5:1 cylinders placed inline
Authors: Abbasi Waqas Sarwar , Ashfaq Khurram , Rahman Hamid
Published: October 2024

The present study explores the impact of gap ratio (G) on the wake dynamics of two rectangular 5:1 cylinders placed inline at a fixed Reynolds number (Re) = 250. The lattice Boltzmann method is used for numerical simulations, and the gap ratio is varied in the range of 0.25–10. After validating the code for flow around a single square cylinder, the simulations are further carried out to explore the impact of gap ratio on the fluid flow past two inline cylinders with a similar aspect ratio = 5:1. Both the cylinders are found to face the reattachment of detached shear layers from front edges on to the side surfaces before the final separation. These reattached shear layers generate vortices on the upper and lower surface of cylinders exhibiting the reverse flow. For G < 4.5, the surface vortices appear on the first cylinder only, while for G ≥ 4.5, the surface vortices appear at both cylinders upper and lower sides. The reattachment point on the surface of the first cylinder is found to move downstream till G = 3, but after that, reverse phenomena occur with an increase in the gap ratio. The enhancement of flow induced lift results due to such separating and reattaching flow. Four distinct flow patterns appear at different gap ratios range: (a) single slender body, (b) non-fully developed duplex shedding, (c) fully developed duplex shedding, and (d) unpredictable vortex shedding. The root mean square value of drag coefficient for the first cylinder is mostly found less as compared to the second cylinder for all G. Negative pressure is observed at the upper, lower, and wake region of both bodies. However, the pressure appears to be positive at the foremost surface of second body when the flow pattern changed from fully developed duplex shedding to unpredictable vortex shedding. Strouhal of both cylinders shows distinct values corresponding to dual frequency at small gap ratios but becomes consistent at higher ones.
Theoretical spin–orbit laser cooling for AlZn molecule
Authors: Rabah Farah , Chmaisani Wael , Younes Ghassan , El-Kork Nayla , Korek Mahmoud
Published: October 2024

A spin–orbit coupling electronic structure study of the AlZn molecule is conducted to investigate the molecular properties of the low-lying electronic states and their feasibility toward direct laser cooling. This study uses the complete active-space self-consistent field level of theory, followed by the multireference configuration interaction method with Davidson correction (+Q). The potential energy and dipole moment curves and the spectroscopic constants are computed for the low-lying doublet and quartet electronic states in the 2S+1Λ± and Ω(±) representations. The transition dipole moments, the Franck–Condon factors, the Einstein coefficient, the radiative lifetimes, the vibrational branching ratio, and the slowing distance are determined between the lowest spin–orbit bound electronic states. These results show that the molecule AlZn has a high potential for laser cooling through the X2Π1/2 → (2)2Π1/2 transition by utilizing four lasers at a wavelength in the ultraviolet region, reaching a sub-microkelvin temperature limit.
Effect of particle stiffness on microgel self-assembly and suspension phase behavior over a broad temperature range
Authors: Misra Chandeshwar , Kawale Sonali Vasant , Behera Sanjay Kumar , Bandyopadhyay Ranjini
Published: October 2024

We synthesized thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) colloidal microgel particles of different stiffnesses by controlling the concentration of a polar crosslinker in a precipitation polymerization synthesis method. When suspended in an aqueous medium, the particles collapsed by expelling water as the temperature was raised toward the volume phase transition temperature (VPTT) of ≈ 34 °C. We noted that the sizes of the stiffer particles, synthesized with higher crosslinker concentration, collapsed less abruptly. Using Fourier transform infrared spectroscopy, we observed enhanced particle dehydration with increasing temperature and decreasing particle stiffness. Oscillatory rheology experiments on dense aqueous PNIPAM suspensions, prepared at a fixed particle effective volume fraction ϕeff = 1.5 at 25°C, revealed that suspensions constituted by the stiffest particles are the most elastic over a broad temperature range. Above the VPTT, suspensions of particles of intermediate stiffnesses exhibited two-step yielding, a typical signature of fragile gel formation. Zeta potential measurements showed that PNIPAM particles of lower stiffnesses are rendered electrostatically unstable in aqueous suspension. Combining cryogenic scanning electron microscopy and rheology, we noted a glass–glass transition when the temperature of a dense suspension of stiff PNIPAM particles was raised across the VPTT. In contrast, suspensions of particles of the lowest stiffnesses showed a gel-viscoelastic liquid–gel transition during an identical temperature ramp experiment. Our study reveals that temperature-induced phase transformations in dense PNIPAM suspensions depend sensitively on the stiffness of the constituent particles and can be explained by considering amphiphilicity-driven morphological changes in the suspension microstructures.
Proper orthogonal decomposition of wall-bounded high-pressure transcritical fluids
Authors: Barea Guillem , Jofre Lluís
Published: October 2024

This study explores the principal modes of high-pressure transcritical channel flow from direct numerical simulation data. The four cases investigated correspond to CO2 at high-pressure conditions (P/Pc=1.5) confined between a cold/bottom wall (T/Tc=0.8−0.95) and a hot/top wall (T/Tc=1.1−1.4); Pc and Tc correspond, respectively, to the pressure and temperature of the critical point. The bulk velocity ranges between Ub=0.5−1.0 m/s with corresponding bulk Reynolds numbers of Reb≈1000−2500. The four cases considered are first characterized into laminar and turbulent regimes, followed by an analysis of energy decay using singular value decomposition. This method allows us to identify the most energetic modes of velocity, temperature, and specific isobaric heat capacity for the laminar and turbulent cases considered. The results reveal that fewer modes are needed to represent the hydrodynamics compared to the thermodynamics of the system. The findings also highlight that the pseudo-boiling region, prevalent in high-pressure transcritical systems, disrupts the coherent structures formed (especially) in the hotter region of the flow. Finally, a correlation analysis between the most energetic modes shows an interdependence between velocity and specific isobaric heat capacity modes when conditioned to focus solely on the pseudo-boiling affected regions. This correlation underscores the complex interplay between hydrodynamic and thermodynamic variables in such high-pressure transcritical environments.
Effects of gap entrance configuration on gap resonances between two free-heaving barges: Higher-order harmonics
Authors: Jing Penglin , He Guanghua , Yang Kaibo , Minoura Munehiko , Xie Binyang
Published: October 2024

The hydrodynamic characteristics of linear and nonlinear gap resonances between two identical side-by-side free-heaving barges are investigated in a numerical wave tank based on the constrained interpolation profile method. This study focuses on the influence of the gap entrance configuration on key hydrodynamic parameters during gap resonances, comparing conditions of round and square edges. Additionally, the effects of incident wave height and the barge's heave responses are examined. The distributions of the first four harmonic components of the key parameters are illustrated, including the wave elevation at the gap, wave run-up on each barge, and wave forces. Numerical results reveal that the gap entrance configuration influences more on the linear gap resonance rather than the nonlinear gap resonances. The higher-order components of the wave elevation at the gap are more sensitive to the incident wave height rather than the edge shape. The influences of the edge shape on the wave forces are mainly manifested in the magnitude of the wave forces rather than in their tendencies. Furthermore, the response time during the development stage of gap resonance is analyzed. The findings indicate that gap resonance develops more quickly with square edges or when the incident wave height increases.
A scattering matrix approach to the effective mass dependence of tunneling current through heterojunctions
Authors: Hernandez Nathaniel , Cahay Marc , O’Mara Jonathan , Ludwick Jonathan , Walker Dennis E. , Back Tyson , Hall Harris
Published: October 2024

A scattering matrix technique is used to calculate the longitudinal and transverse energy dependence of the transmission probability through various heterostructures using both the BenDaniel–Duke (BD) and the lesser known Zhu–Kroemer (ZK) boundary conditions to take into account the spatial dependence of the effective mass. We first illustrate the large difference in the transmission probabilities calculated using both boundary conditions for the simple problems of tunneling through a potential step, a single rectangular barrier, and a resonant tunneling device. Then, we present numerical calculations of the external electric field dependence of the field emission (FE) current from a n-doped GaAs semiconductor/vacuum interface using both boundary conditions, showing that the BD boundary conditions underestimate the FE current for large values of the applied external electrostatic field. A comparison of calculated FE characteristics with FE data may be a way to determine the appropriate boundary conditions to solve tunneling problems through heterostructures with spatially varying effective mass.
Effect of radial inlet distortion on aerodynamic stability in a high load axial flow compressor
Authors: Fan Zhonggang , Liu Yang , Ba Dun , Xu Xiaobin , Zhang Min , Du Juan
Published: October 2024

Radial inlet distortion induced by boundary layer separation can significantly affect the aerodynamic performance of the compressor. The effect of radial inlet distortion on the flow structure is numerically investigated in a high load axial flow compressor. The inlet boundary is determined by the experimental results at the downstream of the distortion generator. The results reveal that tip distortion leads to a reduction in the stall margin, whereas hub distortion extends it. Radial distortion redistributes the main flow toward undistorted region due to the obstructive effect of lattice ring. The deficit in axial velocity with tip radial distortion causes the rotor to operate at a higher incidence angle near the casing, while hub radial distortion alleviates the tip blade loading. The detailed three-dimensional flow field analysis indicates that increased blade loading with tip distortion shifts the trajectories of both primary and secondary tip leakage flow toward the leading edge, thereby expanding the blockage region. Conversely, hub radial distortion unloads the rotor tip region, thereby reducing the blockage region induced by tip leakage flow. Additionally, with hub distortion, the location of separation line on the blade suction surface moves closer to the leading edge, and the flow separation around the trailing edge is intensified.
Pore-scale numerical investigation on spontaneous imbibition in natural fracture with heterogeneous wettability using the volume of fluid method
Authors: Peng Jiajun , Xia Binwei , Lu Yiyu , Hu Huarui
Published: October 2024

Understanding the spontaneous imbibition in the natural fracture with heterogeneous wettability is crucial for predicting and mitigating the impacts of unstable displacement on unconventional recovery. In this paper, the fracture structured mesh model is reconstructed based on the micro-computed tomography (micro-CT) image of naturally fractured tight sandstone. The mineralogy map-based modeling method for heterogeneous-wetting fracture is developed by combining the thin section images, X-ray diffraction (XRD) analysis, and multiple point statistics method. The simulation of the single-phase flow is performed to test the mesh independence. The effects of gravity and wettability on spontaneous imbibition in natural fracture and corresponding imbibition front dynamics are analyzed and discussed using the volume of fluid (VOF) method. The results show that (1) The structured mesh reconstruction method proposed in this paper can more effectively preserve the fracture structure compared to the unstructured mesh reconstruction method. (2) Gravity has a negligible impact on the pore-scale spontaneous imbibition in natural fracture. Under homogeneous-wetting conditions, spontaneous imbibition in natural fracture consistently exhibits stable displacement without significant residual gas formation. However, under the heterogeneous-wetting condition, the spontaneous imbibition displays typical capillary fingering, resulting in approximately 24.04% of the gas being trapped after spontaneous imbibition. The residual gas trapping mechanisms mainly include adhered, isolated, and connected gas. (3) Under both homogeneous- and heterogeneous-wetting conditions, the imbibing water saturation and the length of the imbibition front are proportional to the power of imbibition time during spontaneous imbibition in the natural fracture.
Selective excitation of photon modes in silicon microdisk resonator by deterministic positioning of GeSi quantum dots
Authors: Zinovyev Vladimir A. , Stepikhova Margarita V. , Smagina Zhanna V. , Zinovieva Aigul F. , Bloshkin Alexey A. , Rodyakina Ekaterina E. , Mikhailovskii Mikhail S. , Petrov Mihail I. , Novikov Alexey V.
Published: October 2024

The emission properties of a single Si microdisk resonator with a deterministically embedded GeSi quantum dot (QD) stack have been investigated. The results demonstrate selective excitation of different modes of the resonator depending on the position of QDs. The photoluminescence (PL) spectrum changes dramatically depending on the location of the QDs in the resonator. For the central QD position, the excitation of low Q-factor Mie modes with high field concentration in the center of resonator results in the appearance of a broad PL band. When the stack of QDs is shifted from the center to the edge of the Si resonator, the quenching of this PL band is observed and narrow PL peaks corresponding to whispering gallery modes (WGMs) appear in the PL spectrum. It is found that resonator modes can be excited not only by QDs but also by the radiation of the wetting layer. It is shown that a GeSi island on the top of the QD stack, not covered by silicon, can play the role of a nanoantenna, redirecting radiation to the upper half-space, which is especially important for WGMs that usually radiate sideways.
Dynamics of single cavitation bubble collapse jet under particle-wall synergy
Authors: Wang Xiaoyu , Liang Qi , Yang Yihao , Shen Junwei , Feng Zhengyang , Zhang Yuning , Zhang Yuning
Published: October 2024

The interaction between a particle and a cavitation bubble significantly influences the erosive effect on the wall surface of flow passage components in fluid machinery. This paper investigates the dynamics of a single bubble collapse jet under the synergetic effects of a particle and a wall, using Kelvin impulse theory and high-speed photographic experiments. A theoretical model to predict the intensity and direction of the collapse jet at arbitrary locations near the particle and the wall is constructed on the basis of the image method and Weiss's theorem. The accuracy of the model is verified by comparison with a large number of experimental results. The mechanisms underlying the relative contributions of the particle and wall to the behavior of jet intensity and direction are explored. The effects of key parameters on jet intensity and direction are also quantitatively analyzed, including the relative positions of the particle, wall, and the bubble and the dimensionless particle radius. The main conclusions are as follows: (1) the particle will cause a deflection in the direction of the collapse jet near the wall, leading to the formation of a jet attraction zone. The proposed theoretical model effectively predicts the spatial location of this zone. (2) There exists a region in which the jet is weak, and there is a jet equilibrium point with zero impulse between the particle and the wall. The position of this equilibrium point gradually approaches the wall in a nonlinear manner with increasing particle size and in a quasi-linear manner with decreasing particle–wall distance. (3) When the particle and the bubble are the same distance from the wall, the jet direction gradually changes from toward the particle to vertical to the wall in a nonlinear manner as the bubble–particle distance increases. Moreover, the effective range of the particle's influence on the jet direction decreases as the particle–wall distance decreases.
Underwater acoustic signal feature extraction of mixed flow pump based on empirical wavelet transform
Authors: Xu Wentao , Cheng Li , Jiao Weixuan , Yan Hongqin , Jiang Hongying
Published: October 2024

The pump converts mechanical energy into potential energy, and a mixed-flow-pump combines the characteristics of an axial flow pump and a centrifugal pump. When the mixed-flow-pump operates at low flow conditions, performance instability in the hump region appears on the performance curve. This study investigates the underwater acoustic signal in this area through experiments, computational fluid dynamics (CFD), and computational aero acoustics (CAA). The hysteresis factor calculated by cross correlation (CC) is utilized to improve the dynamic time warping (DTW) signal comparison verification method. The improved method (CC-DTW) improves the ability of DTW in signal comparison and verification. Compared with the fast Fourier transform (FFT) method, it is more convincing in the comparison of experimental and simulation pressure pulsation signals. After verifying the effectiveness of pressure pulsation signals and underwater acoustic signals, a combined empirical wavelet transform and FFT method is used to analyze underwater acoustic signal in instability regions. The results indicate that the depth of instability aligns with the FFT frequence ratio of the intrinsic mode function. Based on the feature, a criterion for determining instability states in mixed-flow-pumps is proposed.
Domain evolution in BiFeO3 epitaxial nanoisland array via post-annealing
Authors: Tian Guo , Zhang Xingchen , Wang Gui , Jin Jun , Zhou Houlin , Dai Ji-Yan , Liu Jun-Ming , Gao Xingsen
Published: October 2024

We describe the impact of post-annealing on ferroelectric-domain structures in arrays of BiFeO3 (BFO) epitaxial nanoislands, which exhibit a domain evolution from an initial 71° stripe/vortex domains to center-convergent topological domains. These results suggest that the increase and redistribution of charged defects, e.g., oxygen vacancies, in BFO nanoislands play a crucial role in driving the formation of center-type domain structures. The observation of defect-driven domain evolution in BFO nanoislands provides a path for further exploring their formation mechanism, topological properties, novel functionalities, and potential applications.
Witch, strumpet, maid and saint
Authors: Borrelli Nathalie
Published: October 2024

Shakespeare’s Henry VI, Part 1 depicts Joan of Arc in contradictory terms. This paper discusses the narrative and literary techniques that are used to develop Joan of Arc’s characterisation, particularly the alternation of location between the Anglo-Burgundian and the French-Armagnac camp, the antagonistic staging of Joan of Arc compared to Lord Talbot and Margaret of Anjou, and the contrastive use of epithets, including the shifting positive, neutral or negative dictionary meanings and context-dependent meanings, as per Ray Jackendoff’s theory of Conceptual Semantics. This results in questioning the apparent meaning of words and concepts and thereby also the apparent judgment on the characters themselves, thus ambiguating, questioning, and ridiculing apparent certainties.
The thematic organization of consumer safety instructions in English
Authors: Herriman Jennifer
Published: October 2024

This study investigates how the content of consumer safety instructions is organized in Themes and N-Rhemes and
connected by thematic progressions. The Themes are chiefly directives or representations of the product and its usage. The goal of
safety instructions, on the other hand, i.e. avoiding dangers and their negative outcomes, is mainly represented in the N-Rhemes.
Thematic progressions are frequently linear, which reflects the expert/non-expert relationship between the writers and readers, or
derived, which reflects the somewhat disjointedness of this text type. There are also many Rheme iterations connecting imperative
clauses. In this respect the thematic organization of procedural texts differs significantly from texts where declarative clauses
are predominant.
Complexity and accuracy of verbal morphology in written L2 Italian
Authors: Spina Stefania
Published: October 2024

The present study aims to verify previous findings on the role of proficiency in the degree of complexity and
accuracy of verbal morphemes in written essays from intermediate and advanced L2 Italian learners. In addition, by taking the
perspective of usage-based theories on the distributional properties in the input, it investigates the extent to which contingency
affects morphological complexity and accuracy by the emergence of cue-outcome associations. Hypotheses on the effects of
contingency and proficiency on complexity and accuracy, and on their mutual relationships, are verified by adopting a confirmatory
approach and by using Structural equation modeling. Results support the claims for non-universal mechanisms in the acquisition of
verbal morphology: proficiency does not affect the morphological complexity of learner texts in the same way in inflectionally
rich and poor languages, and the cue-outcome mechanisms of associative learning work to different extents depending on the
inflectional systems of the target languages.
Mediality vs. materiality
Authors: Wildfeuer Janina
Published: October 2024

This contribution adds a multimodal perspective to the notions of medium and mediality in the
context of media linguistics and critically reflects upon their conceptualisations as ‘technical infrastructures’
and/or ‘socially constituted semiotic procedures’. By critically assessing the different understandings of medium in
media linguistics and multimodality research, it will point out advantages and disadvantages of each concept. In a
second step, the definitions will be applied to practical examples of current media artifacts, i.e., a graphic novel
and a digital learning environment. The application will demonstrate the need for a clear distinction between various
levels of description for both semiotic modes as well as media.
“Do you have an idea what this clown is doing?”
Authors: Luginbühl Martin , Schneider Jan Georg
Published: October 2024

This article examines how the medium TV shaped the first presidential and the vice presidential
debate in the 2020 US election. We will argue that different dimensions of human communication, like medium and
semiotic modes, interact and that therefore the use of semiotic modes like spoken language, moving images or movements
of body parts is shaped by the medial procedure from the outset. Media are therefore more than just technical
infrastructures in a narrow sense, they include the constitution of signs, including their materiality and
processuality. The article will illustrate corresponding media procedures and their interdependence with semiotic
modes, analyzing selected sequences of the two debates. The analysis will show how structural aspects of the medium
shape aspects of the conversation (turn-taking, topic management etc.), of the use of the body (gestures, gaze), and
of camera work (split screen, switched screen). In a last section, we will relate our findings to the
conceptualization of ‘medium’ and ‘canvas’ by Bateman et al. (2017).
General relativistic gravitational induction and causal temperatures
Authors: Hakata Jonathan , Goswami Rituparno , Hansraj Chevarra , Maharaj Sunil D
Published: October 2024

In this paper, we describe the process of general relativistic gravitational induction in spherically symmetric spacetimes by defining an energy momentum tensor for the induction process, which is divergence-free and hence conserved. The aforementioned tensor explicitly describes how the matter-free gravity, as measured by the geometrical Weyl curvature, interacts with the matter. This tensor is clearly different from the energy momentum tensor of the standard matter and we transparently show that in spherical symmetry, the Bianchi identities reduce to the conservation laws for these two such energy momentum tensors. Working with a semitetrad covariant formalism in spherically symmetric spacetimes, we then demonstrate the process of constructing a consistent causal thermodynamical picture for the free gravity and matter interaction via the general non-truncated Israel-Stewart heat transport equation. As an illustrative example, we consider the Lemaitre-Tolman-Bondi spacetime to highlight the relationship between the shear and the Weyl curvature in determining the inductive heat flux.
Influence of external AC transverse magnetic field on air arc oscillation patterns and its application in DC forced current zero techniques
Authors: Zhang Yushi , Wu Yi , Sun Hao , Liu Tianxiao , Wu Yifei , Niu Chunping
Published: October 2024

Direct current (DC) circuit breakers are essential for maintaining the stability of the electric energy transmission and safeguarding the power equipment from the damage caused by the fault currents in DC power systems. The characteristics of the switching arc can be utilized in DC forced current zero techniques. This paper investigates the influence of an external alternating current (AC) transverse magnetic field on the oscillation characteristics of air arc. By confining the arc between two insulating walls and applying a transverse AC magnetic field, the arc exhibits ‘bidirectional oscillation’ and ‘unidirectional oscillation’ modes. The effects of magnetic field amplitude and frequency on the air arc oscillation characteristics are analyzed through experiments, from the aspects of the arc voltages and arc motions. It can be found that an external AC magnetic field can stabilize the arc voltage at a specific oscillation frequency. By connecting an inductor–capacitor (LC) branch in parallel with the arc and setting the LC branch’s resonant frequency equal to the arc voltage oscillation frequency, a current resonance process between the arc and the LC branch can be achieved. This resonance facilitates the creation of the arc current zero-crossing point. A test platform based on the arc oscillation characteristics is established for current interruption experiments. For system currents of 1 kA and 3 kA, the arc current zero-crossing time is controlled within 0.41 ms after applying the external AC transverse magnetic field. The experimental results verify the rationality of the proposed DC breaking scheme.
Luminescence properties of dislocations in α-Ga2O3
Authors: Maruzane Mugove , Oshima Yuichi , Makydonska Olha , Edwards Paul R , Martin Robert W , Massabuau Fabien C-P
Published: October 2024

Dislocations in epitaxial lateral overgrown α-Ga2O3 are investigated using hyperspectral cathodoluminescence spectroscopy. The dislocations are associated with a reduction of self-trapped hole-related luminescence (ca. 3.6 eV line) which can be ascribed to their actions as non-radiative recombination sites for free electrons, to a reduction in free electron density due to Fermi level pinning or to electron trapping at donor states. An increase in the intensity of the ca. 2.8 eV and 3.2 eV lines are observed at the dislocations, suggesting an increase in donor–acceptor pair transitions and providing strong evidence that point defects segregate at dislocations.
Research of anomaly detection based on dynamic anomaly detection enhancement framework
Authors: Xiaoxun Zhu , Songwei Weng , Yu Wang , Zhen Yang , Jingyuan Cao , Xiaoxia Gao , Lijiang Dong , Xiang Lin
Published: October 2024

Anomaly detection (AD) plays a crucial role in various fields, from industrial defect inspection to geological detection. However, traditional approaches often struggle with insufficient discriminability and an inability to generalize to unseen anomalies. These limitations stem from the practical difficulty in gathering a comprehensive set of anomalies and the tendency to overlook anomalous instances in favor of normal samples. To address these challenges, we propose a novel Dynamic AD Enhancement Framework, integrating three key innovations: (1) SaliencyAug: An adaptive saliency-guided augmentation method that generates realistic pseudo-samples to enhance learning of rare anomalies, improving model generalization. (2) DynAB: A dynamic attention block that achieves effective multi-level feature fusion while minimizing redundant information, enhancing detection accuracy. (3) DualOM: A dual-head optimization module which employs separate heads for normal and anomalous sample learning, creating more explicit and discriminative decision boundaries. Extensive experiments across multiple real-world datasets demonstrate our framework’s superior performance in detecting a wide range of anomalies, demonstrating 2.4% improvement over state-of-the-art methods.
A cycle slip detection and repair method based on generalized-cross-validation regularization for BDS-3 quad/pent-frequency data
Authors: Zhao Xingwang , Nie Shuai , Chen Jian , Liu Chao
Published: October 2024

Multi-frequency (quad/pent-frequency) observations improve the success rate for BeiDou Navigation Satellite System (BDS-3) cycle slip detection and repair. Three factors are comprehensively considered: the combination of observation wavelength, the amplification factor of ionospheric delay, and the insensitivity, to select the optimal combination coefficients for BDS-3 multi-frequency cycle slip detection. Due to the ill-conditioned equation in multi-frequency cycle slip repair, the generalized-cross-validation regularization auxiliary LAMBDA method is proposed. To validate the effectiveness of the proposed detection and repair method under different observation environments, two stations are selected for the test. Using real data, the effectiveness of the selected optimal combination coefficients and the proposed method are tested. The conclusions are as follows: (1) for quad-frequency, one geometry-free and ionosphere-free (GFIF) combination [−1, 2, −4, 3] and three linearly independent geometry free carrier phase (GF) combinations [−1, 1, 0, 0], [−1, 1, 1, −1], and [−1, 2, −1, 0] are employed to detect cycle slips. For pent-frequency, one GFIF combination [−2, 2, 1, −2, 1] and four linearly independent GF combinations [−1, 1, 0, 0, 0], [0, 0, −1, 1, 0], [0, 0, −1, 0, 1], and [0, −1, 1, 1, −1] are adopted for cycle slip detection. (2) The algorithm proposed in this paper has been demonstrated to achieve a quad/pent-frequency cycle slip detection success rate of 99.99% and 100% in the coastal environment, and both 100% for quad/pent-frequency detection success in the urban environment. (3) The success rate of repair were 99.27% and 99.94% for the coastal stations, and 99.83% and 100% for the urban stations, respectively. The proposed algorithm offers a dependable approach for the identification and rectification of multi-frequency cycle slips, while also providing a point of reference for the future advancement of multi-frequency cycle slip repair techniques.
Topological phase transitions via attosecond x-ray absorption spectroscopy
Authors: Mosquera Juan F P , Cistaro Giovanni , Malakhov Mikhail , Pisanty Emilio , Dauphin Alexandre , Plaja Luis , Chacón Alexis , Lewenstein Maciej , Picón Antonio
Published: October 2024

We present a numerical experiment that demonstrates the possibility to capture topological phase transitions via an x-ray absorption spectroscopy scheme. We consider a Chern insulator whose topological phase is tuned via a second-order hopping. We perform time-dynamics simulations of the out-of-equilibrium laser-driven electron motion that enables us to model a realistic attosecond spectroscopy scheme. In particular, we use an ultrafast scheme with a circularly polarized IR pump pulse and an attosecond x-ray probe pulse. A laser-induced dichroism-type spectrum shows a clear signature of the topological phase transition. We are able to connect these signatures with the Berry structure of the system. This work extend the applications of attosecond absorption spectroscopy to systems presenting a non-trivial topological phase.
True pinch mode of magnetorheological fluids
Authors: Sapiński Bogdan , Macháček Ondřej , Kubík Michal , Gołdasz Janusz , Žáček Jiří , Bańkosz Wojciech
Published: October 2024

Magnetorheological (MR) fluids are representatives of smart materials. They react to magnetic fields by developing a yield stress. The effect has been employed in real-world applications such as automotive chassis systems or optical finishing. By convention, MR devices can be operated in at least one of the fundamental modes: flow, shear, squeeze, gradient pinch of which the former has been the least studied and understood. In pinch mode, the material in the flow channel is exposed to non-uniform magnetic fields in the direction parallel to fluid flow. As a result, only the volume of MR fluid near the channel walls are energized to modify the particular material property (yield stress). The result is the channel’s effective diameter change. The behavior of the material in pinch mode is unique and unseen in the other controllable fluids. To study the material’s characteristics in the specific mode, the authors developed a novel circuit concept for energizing the material in an effort to achieve the ‘true-zero’ pinch mode magnetic behavior. Contrary to the existing pinch mode valve concepts, the concept valve allows to achieve zero magnetic flux density in the center of the flow channel regardless of the current level. To test the hypothesis a prototype valve was modeled, manufactured and tested across a range of external (flow rate, current/magnetic flux) stimuli. The obtained results yield sufficient evidence proven by results of magnetic simulations to support the underlying hypothesis. The experimental results illustrate the pinch mode type behaviour, i.e. the slope change in the pressure vs flow rate characteristics.
Phase transition analysis of the Potts-SOS model with spin set {−1,0,+1} on the Cayley tree
Authors: Akın Hasan
Published: October 2024

Recently, the Potts-SOS model on Cayley trees was studied using the Kolmogorov consistency condition to investigate the existence and properties of Gibbs measures. The author previously examined the thermodynamic properties of the one-dimensional Potts-SOS model on the positive natural number lattice

N

, demonstrating the absence of phase transitions [Akin H, Phys. Scr. 99 (2024), 055 231]. In this study, we apply the cavity method to explore the non-uniqueness of Gibbs measures for the Potts-SOS model with spins {–1, 0, + 1} on a second-order semi-infinite Cayley tree. We address the phase transition problem by analyzing the model’s iterative equation system and perform stability analysis at fixed points to determine regions where phase transitions occur.
A study on analytical solutions of one of the important shallow water wave equations and its stability analysis
Authors: Deniz H Arzu , Özkan E Mehmet , Özkan Ayten
Published: October 2024

The present research uses the modified

w

g

-expansion technique to give analytical solutions for the nonlinear time fractional integro-differential Kadomtsev-Petviashvili (KP) hierarchy equation with beta fractional derivative. The modified

w

g

-expansion technique is an important method for finding analytical solutions to nonlinear equations. The suggested approach produces three sorts of solutions: trigonometric, hyperbolic, and rational. These answers have been discovered with the aid of a software tool. Additionally, stability analysis of observed governing model solutions is used to validate scientific calculations. Furthermore, the 3-dimensional, contour, and 2-dimensional images are provided for a better understanding of the behavior of the solutions.
Study of lanthanide based Ln2MgSe4 (Ln = Er, Pm) spinels for spintronic and optoelectronic applications
Authors: Murtaza Sadia , Ishfaq Mudassir , Aldaghfag Shatha A , Yaseen Muhammad , Nasarullah  , Hamza Muhammad
Published: October 2024

Herein, the full potential linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory (DFT) is used to examine the physical features of Ln2MgSe4 (Ln = Er, Pm) spinel selenides. Exchange correlation energies are estimated through modified Becke–Johnson potential (mBJ). Band structures (BS) and density of states (DOS) data proved that Er2MgSe4 is ferromagnetic (FM) semiconductor while Pm2MgSe4 is half metallic (HFM) ferromagnetic in nature. The Er-f contributed majorly to the vicinity of Fermi level for both compounds. The structural stability is determined through calculating the tolerance factor and geometry optimization, while thermodynamical stability has been realized by computing the formation enthalpy. Furthermore, various optical parameters have been computed which describe the considered materials’ response to incident light. Our study explored the physical properties of two Ln based spinels which are found to have potential for being used in various optoelectronic and spintronic devices.
Optimization strategies for operational parameters of Rydberg atom-based amplitude modulation receiver
Authors: Wu 吴 Yuhao 宇豪 , Xiao 肖 Dongping 冬萍 , Zhang 张 Huaiqing 淮清 , Yan 阎 Sheng 晟
Published: October 2024

The Rydberg atom-based receiver, as a novel type of antenna, demonstrates broad application prospects in the field of microwave communications. However, since Rydberg atomic receivers are nonlinear systems, mismatches between the parameters of the received amplitude modulation (AM) signals and the system’s linear workspace and demodulation operating points can cause severe distortion in the demodulated signals. To address this, the article proposes a method for determining the operational parameters based on the mean square error (MSE) and total harmonic distortion (THD) assessments and presents strategies for optimizing the system’s operational parameters focusing on linear response characteristics (LRC) and linear dynamic range (LDR). Specifically, we employ a method that minimizes the MSE to define the system’s linear workspace, thereby ensuring the system has a good LRC while maximizing the LDR. To ensure that the signal always operates within the linear workspace, an appropriate carrier amplitude is set as the demodulation operating point. By calculating the THD at different operating points, the LRC performance within different regions of the linear workspace is evaluated, and corresponding optimization strategies based on the range of signal strengths are proposed. Moreover, to more accurately restore the baseband signal, we establish a mapping relationship between the carrier Rabi frequency and the transmitted power of the probe light, and optimize the slope of the linear demodulation function to reduce the MSE to less than 0.8 × 10−4. Finally, based on these methods for determining the operational parameters, we explore the effects of different laser Rabi frequencies on the system performance, and provide optimization recommendations. This research provides robust support for the design of high-performance Rydberg atom-based AM receivers.
Neural decoding and feature selection methods for closed-loop control of avoidance behavior
Authors: Liu Jinhan , Younk Rebecca , M Drahos Lauren , S Nagrale Sumedh , Yadav Shreya , S Widge Alik , Shoaran Mahsa
Published: October 2024

Objective. Many psychiatric disorders involve excessive avoidant or defensive behavior, such as avoidance in anxiety and trauma disorders or defensive rituals in obsessive-compulsive disorders. Developing algorithms to predict these behaviors from local field potentials (LFPs) could serve as the foundational technology for closed-loop control of such disorders. A significant challenge is identifying the LFP features that encode these defensive behaviors. Approach. We analyzed LFP signals from the infralimbic cortex and basolateral amygdala of rats undergoing tone-shock conditioning and extinction, standard for investigating defensive behaviors. We utilized a comprehensive set of neuro-markers across spectral, temporal, and connectivity domains, employing SHapley Additive exPlanations for feature importance evaluation within Light Gradient-Boosting Machine models. Our goal was to decode three commonly studied avoidance/defensive behaviors: freezing, bar-press suppression, and motion (accelerometry), examining the impact of different features on decoding performance. Main results. Band power and band power ratio between channels emerged as optimal features across sessions. High-gamma (80–150 Hz) power, power ratios, and inter-regional correlations were more informative than other bands that are more classically linked to defensive behaviors. Focusing on highly informative features enhanced performance. Across 4 recording sessions with 16 subjects, we achieved an average coefficient of determination of 0.5357 and 0.3476, and Pearson correlation coefficients of 0.7579 and 0.6092 for accelerometry jerk and bar press rate, respectively. Utilizing only the most informative features revealed differential encoding between accelerometry and bar press rate, with the former primarily through local spectral power and the latter via inter-regional connectivity. Our methodology demonstrated remarkably low training/inference time and memory usage, requiring

<

310 ms for training,

<

0.051 ms for inference, and 16.6 kB of memory, using a single core of AMD Ryzen Threadripper PRO 5995WX CPU. Significance. Our results demonstrate the feasibility of accurately decoding defensive behaviors with minimal latency, using LFP features from neural circuits strongly linked to these behaviors. This methodology holds promise for real-time decoding to identify physiological targets in closed-loop psychiatric neuromodulation.
The 140 GHz notch filter development for millimeter-wave diagnostics protection on the stellarator Wendelstein 7-X
Authors: Himes Logan , Qiu Shasha , Domier Calvin , Li Xiaoliang , Zhu Yilun , Jr Neville Luhmann
Published: October 2024

The notch filter plays a crucial role as a protective
component in microwave diagnostics, primarily by addressing issues
related to catastrophic interference. Designed for millimeter-wave
diagnostics on the stellarator Wendelstein 7-X (W7-X), a WR-6
waveguide-based notch filter has been successfully developed to
effectively isolate leakage from auxiliary heating gyrotrons
operating at 140 GHz. The filter incorporates cylindrical cavities
resonating at 140 GHz for the TE11p mode, with coupling
structures that are designed and optimized for high-efficiency
coupling. This configuration simplifies fabrication, thereby
ensuring high-yield production. Experimental fabrication and
in-house characterization confirm the notch filter's exceptional
performance, with over 60 dB rejection in the vicinity of 140 GHz
and low insertion loss (< 2 dB) above and below the notch
frequency across a broad frequency bandwidth (121–138 GHz,
142–163 GHz). The utilization of this high-frequency structure
fabrication technology can be applied to millimeter-wave diagnostics
on other machines. In addition to the design elements of the notch
filter, this paper also provides a detailed discussion of the
fabrication process and methodology.
The natural history and multitrophic ecological network of the highly restricted butterfly Catasticta truncata (Lepidoptera Pieridae) from urban areas of Loja, Ecuador
Authors: Padrón Pablo Sebastián
Published: October 2024

This study describes the natural history and multitrophic interactions of the highly restricted Andean butterfly species Catasticta truncata (Lathy & Rosenberg, 1912) from the urban and surrounding areas of Loja in southern Ecuador. The immature stages of the butterfly are described and illustrated, and the host plant is identified as Phoradendron nervosum Oliv. (Viscaceae), an aerial-stem hemiparasitic shrub that parasitizes trees of Salix humboldtiana (Willd) (Salicaceae). Multitrophic interactions that this species maintains in the urban ecosystem are described. One interaction includes a predator, Ambastus villosus Stal, 1872 (Reduvidae). In addition, and for the first time for the genus Catasticta Butler, 1870, the presence of an endoparasitoid wasp (Ichneumonidae) and a hyperparasitoid (secondary parasitoid) wasp Pediobius sp. (Eulophidae), both potentially undescribed species, are documented. Flowers from plants in the Asteraceae family are visited by adults of C. truncata. This new information highlights the ecological roles of these butterflies in the green areas within the city of Loja. Finally, due to the highly restricted distribution of this species within Loja’s green areas and the striking beauty of adults, along with this butterfly being a component within 4 trophic levels in the urban ecological network, this butterfly could be a flagship for the city of Loja. Local actions that help the conservation of this species should positively affect the organisms that interact with it and positively influence the well-being of the city’s inhabitants in general.
Effect of disability, homelessness, and neighborhood marginalization on risk-adjustment for hospital performance measurement
Authors: Roberts Surain B , Colacci Michael , Shi Jiamin , Brown Hilary K , Asrhaf Mahliqa , Stukel Therese , Razak Fahad , Verma Amol A
Published: October 2024

Background

It is not known how disability, homelessness, or neighborhood marginalization influence risk-adjusted hospital performance measurement in a universal health care system.

Methods

We evaluated the effect of including these equity-related factors in risk-adjustment models for in-hospital mortality, and 7- and 30-day readmission in 28 hospitals in Ontario, Canada. We compared risk-adjustment with commonly-used clinical factors to models that also included homelessness, disability, and neighborhood indices of marginalization. We evaluated models in historical data using internal-external cross-validation. We calculated risk-standardized outcome rates for each hospital in a recent reporting period using mixed-effects logistic regression.

Results

The cohort included 544,805 admissions. Adjustment for disability, homelessness, and neighborhood marginalization had little impact on discrimination or calibration of risk-adjustment models. However, it influenced comparative hospital performance on risk-standardized 30-day readmission rates, resulting in 5 hospitals being reclassified between below-average, average, and above-average groups. No hospitals were reclassified for mortality and 7-day readmission.

Conclusion

In a system with universally insured hospital services, adjustment for disability, homelessness, and neighborhood marginalization influenced estimates of hospital performance for 30-day readmission but not 7-day readmission or in-hospital mortality. These findings can inform researchers and policymakers as they thoughtfully consider when to adjust for these factors in hospital performance measurement.