bluuebunny/crossref_metadata_2025 huggingface dataset:
Synchronization and bifurcation in an economic model
Authors: Camargo Victor E. , Amaral Amaury S. , Crepaldi Antônio F. , Ferreira Fernando F.
Published: October 2022

We study the synchronization of two coupled idealized economies. In the present work, we consider a recently developed economic system that shows a richness of dynamical behavior. By means of the Lyapunov exponents, we analyze that there is overly complex behavior in the transitions in the dynamics of an isolated economy, oscillating between chaotic attractors and limit cycles. Then, for two coupled economies, we analyze the synchronization states for the space of all control parameters as a function of the network coupling parameter. Interestingly, we have evidenced that there is a broad region of fully synchronized states and as we increase the coupling, some phenomena such as a smooth and intermittent loss in synchronization emerge. In the same way, we observe phase synchronization for one of the control parameters. Ultimately, in order to confirm this loss of synchronization, we inspect the stability of synchronized states through the master stability function method for some control parameters. Here, we corroborate what was previously observed, the unexpected vast range of control parameter values of instability corresponding to desynchronization.
High output performance of piezoelectric energy harvesters using epitaxial Pb(Zr, Ti)O3 thin film grown on Si substrate
Authors: Kim Eun-Ji , Kweon Sang-Hyo , Nahm Sahn , Sato Yukio , Tan Goon , Kanno Isaku
Published: October 2022

For a high power density in piezoelectric energy harvesters, both a large direct piezoelectric coefficient (e31,f) and a small relative permittivity constant (εr,33) are required. This study proposed an energy harvesting device made of an epitaxial Pb(Zr, Ti)O3 (PZT) thin film grown on a Si substrate. The epitaxial PZT thin film is deposited on the Si substrate by RF magnetron sputtering. The epitaxial PZT thin film grown on Si substrate has a εr,33 constant of 318. The output voltage as a function of input displacement was measured using a shaker to evaluate the direct e31,f coefficients and energy harvester output characteristics. According to the figure of merit defined as (e31,f)2/ε0εr,33, the epitaxial PZT/Si cantilever is 32 GPa. At a resonant frequency of 373 Hz under an acceleration of 11 m/s2, the epitaxial PZT/Si cantilever has a high output power of 40.93 μW and power density of 108.3 μW/cm2/g2 without any damage, which is very promising for high power energy harvester applications.
Dynamic nonlocal passive scalar subgrid-scale turbulence modeling
Authors: Seyedi S. Hadi , Akhavan-Safaei Ali , Zayernouri Mohsen
Published: October 2022

Extensive experimental evidence highlights that scalar turbulence exhibits anomalous diffusion and stronger intermittency levels at small scales compared to that in fluid turbulence. This renders the corresponding subgrid-scale dynamics modeling for scalar turbulence a greater challenge to date. We develop a new large eddy simulation (LES) paradigm for efficiently and dynamically nonlocal LES modeling of the scalar turbulence. To this end, we formulate the underlying nonlocal model starting from the filtered Boltzmann kinetic transport equation, where the divergence of subgrid-scale scalar fluxes emerges as a fractional-order Laplacian term in the filtered advection–diffusion model, coding the corresponding superdiffusive nature of scalar turbulence. Subsequently, we develop a robust data-driven algorithm for estimation of the fractional (noninteger) Laplacian exponent, where we, on the fly, calculate the corresponding model coefficient employing a new dynamic procedure. Our a priori tests show that our new dynamically nonlocal LES paradigm provides better agreement with the ground-truth filtered direct numerical simulation data in comparison to the conventional static and dynamic Prandtl–Smagorinsky models. Moreover, in order to analyze the numerical stability and assessing the model's performance, we carry out comprehensive a posteriori tests. They unanimously illustrate that our new model considerably outperforms other existing functional models, correctly predicting the backscattering phenomena and, at the same time, providing higher correlations at small-to-large filter sizes. We conclude that our proposed nonlocal subgrid-scale model for scalar turbulence is amenable for coarse LES and very large eddy simulation frameworks even with strong anisotropies, applicable to environmental applications.
Variability analysis of ferroelectric FETs in program operation using low-frequency noise spectroscopy
Authors: Shin Wonjun , Bae Jong-Ho , Kim Jaehyeon , Koo Ryun-Han , Kim Jae-Joon , Kwon Daewoong , Lee Jong-Ho
Published: October 2022

We investigate the variability of a ferroelectric FET (FEFET) in program operation using low-frequency noise (LFN) spectroscopy. Contrary to the previous report, LFN characteristics of FEFETs differ significantly depending on the program [low threshold voltage (Vth)] or erase state [high Vth)] [Shin et al., IEEE Electron Device Lett. 43, 13 (2022)]. Furthermore, the 1/f noise variation of the FEFETs is much larger in the program state than that in the erase state. It is revealed that the change in the number of electrons trapped at the FE/dielectric interface and oxygen vacancy in each program operation is the main reason for the variability of the FEFET in program operation. The variation stemming from the change in the number of trapped charges is significantly worsened when the channel area is scaled down.
Emergence phenology of Tasmanian mayflies (Ephemeroptera) in a first-order creek and comparison with northern hemisphere confamilials
Authors: Thresher Ronald E.
Published: October 2022

Context Australian mayflies are hypothesised to differ from those in the Northern Hemisphere by having longer, more variable emergence seasons that overlap more widely among taxa. Aim To test this hypothesis by comparing the behaviour of related northern and southern hemisphere species in similar habitats and at similar spatial scales. Methods Emergence dates were recorded fortnightly over two consecutive years, one ‘warm’ and one ‘cool’, in a rocky creek in south-eastern Tasmania, and at a coarser scale for Tasmania as whole, spanning an ∼20-year period. The results are compared with emergence patterns at two sites in the northern hemisphere climatically similar to Tasmania. Key results Durations of emergence seasons in Tasmania did not differ significantly at either the single site or whole of island scales from those in the northern hemisphere, but unlike in the latter, the start of emergence does not appear to be temperature-dependent. Conclusions Apparent regional differences are likely to result primarily from climatically inappropriate comparisons rather than from fundamental differences in behaviour. Implications Differences in the factor(s) that cue emergence suggest that the life histories of mayflies in Tasmania, and possibly elsewhere in Australia, are determined less by physiology than by aquatic ecology.
COVID-19, climate change, and the finite pool of worry in 2019 to 2021 Twitter discussions
Authors: Smirnov Oleg , Hsieh Pei-Hsun
Published: October 2022

Climate change mitigation has been one of the world's most salient issues for the past three decades. However, global policy attention has been partially diverted to address the COVID-19 pandemic for the past 2 y. Here, we explore the impact of the pandemic on the frequency and content of climate change discussions on Twitter for the period of 2019 to 2021. Consistent with the “finite pool of worry” hypothesis both at the annual level and on a daily basis, a larger number of COVID-19 cases and deaths is associated with a smaller number of “climate change” tweets. Climate change discussion on Twitter decreased, despite 1) a larger Twitter daily active usage in 2020 and 2021, 2) greater coverage of climate change in the traditional media in 2021, 3) a larger number of North Atlantic Ocean hurricanes, and 4) a larger wildland fires area in the United States in 2020 and 2021. Further evidence supporting the finite pool of worry is the significant relationship between daily COVID-19 cases/deaths on the one hand and the public sentiment and emotional content of climate change tweets on the other. In particular, increasing COVID-19 numbers decrease negative sentiment in climate change tweets and the emotions related to worry and anxiety, such as fear and anger.
A comparison of automated and manual analyses of syntactic complexity in L2 English writing
Authors: Châu Quang Hồng , Bulté Bram
Published: October 2022

Automated tools for syntactic complexity measurement are increasingly used for analyzing various kinds of second
language corpora, even though these tools were originally developed and tested for texts produced by advanced learners. This study
investigates the reliability of automated complexity measurement for beginner and lower-intermediate L2 English data by comparing
manual and automated analyses of a corpus of 80 texts written by Dutch-speaking learners. Our quantitative and qualitative
analyses reveal that the reliability of automated complexity measurement is substantially affected by learner errors, parser
errors, and Tregex pattern undergeneration. We also demonstrate the importance of aligning the definitions of
analytical units between the computational tool and human annotators. In order to enhance the reliability of automated analyses,
it is recommended that certain modifications are made to the system, and non-advanced L2 English data are preprocessed prior to
automated analyses.
Rhoticity in Southern New Zealand English
Authors: Schilk Marco , Pickert Lena
Published: October 2022

Though generally considered a non-rhotic variety, New Zealand English (NZE) shows some variation in terms of rhotic vowel colouring, mainly observed in southern New Zealand speakers. The current study uses an acoustic approach to a new audio-visual database, the UC Canterbury QuakeBox (Walsh et al. 2013) to account for variation in the degree of rhotic vowel colouring in southern NZE speakers. Identifying all nurse vowels in the data of eight representative speakers with interview transcripts, auditory perception, and a Praat-based acoustic analysis, rhotic vowel colouring is subsequently rated based on third formant (F3) realization. Results show that southern speakers display rhotic vowel colouring to varying degrees. A mixed-effects model and qualitative interpretation of key speakers further suggest an age-based cline of rhoticity with younger speakers converging on the non-rhotic standard, indicating that this rhotic vowel colouring in Southern speakers may be due to resistance to dialect levelling rather than ongoing differentiation.
MuPDAR for corpus-based learner and variety studies
Authors: Gries Stefan Th.
Published: October 2022

Corpus-based studies of learner language and (especially) English varieties have become more quantitative in nature and increasingly use regression-based methods and classifiers such as classification trees, random forests, etc. One recent development that is becoming more widely used is the MuPDAR (Multifactorial Prediction and Deviation Analysis using Regressions) approach of Gries and Deshors (2014) and Gries and Adelman (2014). This approach attempts to improve on traditional regression- or tree-based approaches by, firstly, training a model/classifier on the reference speakers (often native speakers in learner corpus studies or British English speakers in variety studies), then, secondly, using this model/classifier to predict what such a reference speaker would produce in the situation the target speaker is in (often non-native speakers or indigenized-variety speakers). The third step then consists of determining whether the target speakers made a canonical choice or not and explore that variability with a second regression model or classifier. The present paper is a follow-up to Gries and Deshors’s (2020) and offers additional answers to a variety of questions that readers and audiences to MuPDAR presentations have been raising for a few years. First, I show how MuPDAR can be extended straightforwardly to alternations that involve more than the typically used binary choices; I do so in a way that also addresses another potential challenge and exemplify this with a case study from varieties research. Second, I outline a casewise-similarity approach towards predicting what reference speakers would do that avoids frequent regression modeling problems and exemplify, as well as compare, it to competing alternatives with a case study from learner corpus research.
Strongly Lensed Transient Sources: A Review
Authors: Liao Kai , Biesiada Marek , Zhu Zong-Hong
Published: October 2022

The past decades have witnessed a lot of progress in gravitational lensing with two main targets: stars and galaxies (with active galactic nuclei). The success is partially attributed to the continuous luminescence of these sources making the detection and monitoring relatively easy. With the running of ongoing and upcoming large facilities/surveys in various electromagnetic and gravitational-wave bands, the era of time-domain surveys would guarantee constant detection of strongly lensed explosive transient events, for example, supernovae in all types, gamma ray bursts with afterglows in all bands, fast radio bursts, and even gravitational waves. Lensed transients have many advantages over the traditional targets in studying the Universe, and magnification effect helps to understand the transients themselves at high redshifts. In this review article, on base of the recent achievements in literature, we summarize the methods of searching for different kinds of lensed transient signals, the latest results on detection and their applications in fundamental physics, astrophysics, and cosmology. At the same time, we give supplementary comments as well as prospects of this emerging research direction that may help readers who are interested in entering this field.
Microstructure, electrical, optical and electrochemical characteristics of silver phosphate glasses cathode for magnesium battery applications
Authors: Khalil R M , Hameed Talaat A , Farrag M , Sheha E , Ali A A , Salman F , Solyman S
Published: October 2022

The realization of a practical magnesium battery is combined with the development of a high kinetic cathode and compatible electrolyte to facilitate the redox process. For this reason, silver phosphate glasses in the binary system (Fe2O3–AgPO3) are prepared using the conventional quenching method. The glasses were defined in the form [Fe2O3]
x
[AgPO3](100−x) and the composition with 0 ⩽ x ⩽ 40 wt. %. The molar volumes and densities were measured. These glass systems were characterized using x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–Vis–NIR spectrophotometer, electrochemical procedures and impedance spectroscopy. X-ray diffraction revealed that pristine AgPO3 sample was formed in a glassy state, whereas two crystalline phases (AgFeP2O7 and Fe2O3) were formed after the incorporation of Fe2O3 by different concentrations. Bond assignments associated with different functional groups were investigated by an FT-IR spectroscopy. The values of the band gap were decreased with the increase of Fe2O3 content. The effect of grains and grain boundaries in a heterostructure made up of Fe2O3 and AgFeP2O7 crystallites grown in silver phosphate glasses was studied using impedance spectroscopy. The complex impedance, electrical conductivity, and complex electric modulus were measured in terms of frequency and temperature dependency in [Fe2O3]
x
–[AgPO3](1−x). In the studied glass systems, non-Debye relaxation was observed. Under a variable regime, σ
ac conductivity follows a modified Jonscher’s law Arrhenius fitting of multiple relaxation processes in the material yielded activation energy of (0.12 eV–0.271 eV) which support a Maxwell–Wagner relaxation model in the heterostructure glasses at high temperatures and low frequencies. The dc conductivity decreases with iron rate and follows the Arrhenius law with very low activation energy (0.12–0.27 eV. Mg//electrolyte//Glass coin cells are assembled and show an initial discharge capacity of up to ∼564 mAh g−1. These materials are attractive for application in modernistic electrochemical devices because of their great compositional and preparation variety which enables tuning the types and techniques of electrical conduction in the material.
Research on soft compensation of the potential drift signal of a pH electrode based on a gated recurrent neural network
Authors: Chen Ying , Xu Chongxuan , Zhao Xueliang
Published: October 2022

As a convenient chemical sensor, the pH electrode is widely used in the measurement of the pH value of water bodies. However, due to structural aging and environmental influences, the pH electrode is prone to drift, which directly results in the inability to obtain accurate measurement results. Based on the above problems, this paper proposes a cascade structure soft compensation model with the gated recurrent unit (GRU) as the main body. The model uses the complete ensemble empirical mode decomposition with adaptive noise with permutation entropy (CEEMDAN-PE) method to obtain the main characteristics of the pH electrode potential drift signal to reduce the interference of noise in the actual measurement environment, and uses its output as the input of the GRU neural network to obtain the prediction results and compensate for the drift signal. This model is called the CEEMDA-PE & GRU (CPG) model. In this paper, the CPG model is compared with the commonly used time series prediction model, and the results show that the prediction effect of this model is better than other models. The root mean squared error, mean absolute error, and mean absolute percentage error of the prediction model are reduced by 60.97%, 65.53%, and 66.55%, respectively. Finally, this paper proposes the concept of the degree of compensation to evaluate the compensation effect. The average degree of compensation of the soft compensation method is above 83%. The results show that the soft compensation method can improve the measurement accuracy of the pH electrode and has good robustness.
Correction and pointer reading recognition of circular pointer meter
Authors: Ji Dongsheng , Zhang Wenbo , Zhao Qianchuan , Yang Wen
Published: October 2022

For the meter images collected in an actual environment, there is the possibility of tilt and rotation. This paper presents a method to calibrate the circular pointer-type meter based on YOLOv5s network. The convolutional neural network framework is used to detect the scale value in the meter panel as the key point. The position information and value information of the detected scale value are used to fit the elliptic equation of the position of the scale value with the least square method for perspective correction and rotation correction of the meter, and the corrected meter image is used to obtain the meter pointer reading. This paper proposes the weighted angle method to read the meter reading. After multiple transformations, the accumulated error of the meter image is eliminated. Finally, comparing the pointer detection method of this paper with the traditional pointer detection method, the error of this detection method is smaller; comparing the meter reading results before and after correction, the meter reading error after correction is 50% less than before correction. Comparing the method in this paper with other mainstream methods, it proves the effectiveness of the our method.
CoMo layered double hydroxide equipped with carbon nanotubes for electrocatalytic oxygen evolution reaction
Authors: Yan Xuesheng , Wang Zhaolong , Bao Jian , Song Yanhua , She Xiaojie , Yuan Junjie , Hua Yingjie , Lv Guoai , Li Huaming , Xu Hui
Published: October 2022

To carry out effective resource reforming of sustainable electricity, hydrogen production by electrochemical water splitting provides an eco-friendly and economical way. Nevertheless, the oxygen evolution reaction (OER) at the anode is limited by the slow reaction process, which hinders the large-scale development and application of electrolysis technology. In this work, we present an electrocatalyst with superior OER performance, which attributed to the abundant active sites and good electronic conductivity. The two-dimensional CoMo Layered Double Hydroxide nanosheets are synthesized and deposited on conductive carbon nanotubes (CoMo LDH/CNTs), and then hybrid composites show better catalytic performance than their undecorated counterpart under identical conditions. Specifically, CoMo LDH/CNTs exhibit the low overpotential of 268 mV to obtain 10 mA cm−2 and satisfactory stability (more than 40 h). We emphasize that this hybridization strategy with a conductive supporting framework could design more abundant and low-cost OER electrocatalysts to minimize electrical energy consumption, thereby achieving efficient conversion between energy sources.
Revisiting multi-breathers in the discrete Klein–Gordon equation: a spatial dynamics approach
Authors: Parker Ross , Cuevas-Maraver Jesús , Kevrekidis P G , Aceves Alejandro
Published: October 2022

We consider the existence and spectral stability of multi-breather structures in the discrete Klein–Gordon equation, both for soft and hard symmetric potentials. To obtain analytical results, we project the system onto a finite-dimensional Hilbert space consisting of the first M Fourier modes, for arbitrary M. On this approximate system, we then take a spatial dynamics approach and use Lin’s method to construct multi-breathers from a sequence of well-separated copies of the primary, single-site breather. We then locate the eigenmodes in the Floquet spectrum associated with the interaction between the individual breathers of such multi-breather states by reducing the spectral problem to a matrix equation. Expressions for these eigenmodes for the approximate, finite-dimensional system are obtained in terms of the primary breather and its kernel eigenfunctions, and these are found to be in very good agreement with the numerical Floquet spectrum results. This is supplemented with results from numerical timestepping experiments, which are interpreted using the spectral computations.
Variational resolution of outflow boundary conditions for incompressible Navier–Stokes
Authors: Bathory Michal , Stefanelli Ulisse
Published: October 2022

This paper focuses on the so-called weighted inertia-dissipation-energy variational approach for the approximation of unsteady Leray–Hopf solutions of the incompressible Navier–Stokes system. Initiated in (Ortiz et al 2018 Nonlinearity
31 5664–82), this variational method is here extended to the case of non-Newtonian fluids with power-law index r ⩾ 11/5 in three space dimension and large nonhomogeneous data. Moreover, boundary conditions are not imposed on some parts of boundaries, representing, e.g., outflows. Correspondingly, natural boundary conditions arise from the minimisation. In particular, at walls we recover boundary conditions of Navier-slip type. At outflows and inflows, we obtain the condition

−

1

2

|
v

|

2

n
+
T
n
=
0

. This provides the first theoretical explanation for the onset of such boundary conditions.
Dispersive effects in a scalar nonlocal wave equation inspired by peridynamics
Authors: Coclite Giuseppe Maria , Dipierro Serena , Fanizza Giuseppe , Maddalena Francesco , Valdinoci Enrico
Published: October 2022

We study the dispersive properties of a linear equation in one spatial dimension which is inspired by models in peridynamics. The interplay between nonlocality and dispersion is analyzed in detail through the study of the asymptotics at low and high frequencies, revealing new features ruling the wave propagation in continua where nonlocal characteristics must be taken into account. Global dispersive estimates and existence of conserved functionals are proved. A comparison between these new effects and the classical local scenario is deepened also through a numerical analysis.
Normalized solutions to p-Laplacian equations with combined nonlinearities*
Authors: Zhang Zexin , Zhang Zhitao
Published: October 2022

In this paper, we study the p-Laplacian equation with a L

p
-norm constraint:

−

Δ

p

u
=
λ
|
u

|

p
−
2

u
+
μ
|
u

|

q
−
2

u
+
g

(

u

)

in

R

N

,

∫

R

N

|
u

|

p

d
x
=

a

p

,

where N ⩾ 2, a > 0,

1
<
p
<
q
⩽

p

¯

≔
p
+

p

2

N

,

μ
∈
R

,

g
∈
C

(

R
,
R

)

and

λ
∈
R

is a Lagrange multiplier, which appears due to the mass constraint ‖u‖
p
= a. We assume that g is odd and L

p
-supercritical. When

q
<

p

¯

and μ > 0, we use Schwarz rearrangement and Ekeland variational principle to prove the existence of positive radial ground states for suitable μ. When

q
=

p

¯

and μ > 0 or

q
⩽

p

¯

and μ ⩽ 0, with an additional condition of g, we obtain a positive radial ground state if μ lies in a suitable range, by the Schwarz rearrangement and minimax theorems. Via a fountain theorem type argument, with suitable

μ
∈
R

, we obtain infinitely many radial solutions for any N ⩾ 2 and establish the existence of infinitely many nonradial sign-changing solutions for N = 4 or N ⩾ 6. In any case mentioned above, the range of μ depends on the value of a: |μ| can be large if a > 0 is small.
A simple stability criterion for dynamical systems with stochastic switching and/or stochastic time-delays
Authors: Carter Camille , Murri Jacob , Reber David , Webb Benjamin
Published: October 2022

In many natural and technological systems the rule that governs the system’s dynamics changes over time. In such switched systems the system’s switching can be a significant source of instability. Here we give a simple sufficient criterium to determine if an i.i.d. stochastically switched system is stable in expectation. This method extends recent results for linear switched systems to nonlinear switched systems. It also extends results known for general switched systems giving improved results for systems with i.i.d. stochastic switching. The paper also considers the effects of time-delays on the stability of switched systems. Such time delays, which are intrinsic to any real-world system, can also have a destabilising effect on the system’s dynamics. Previously, it has been shown that if a dynamical system is intrinsically stable, which is a stronger form of global stability, then it maintains its stability even when time-delays are introduced into the system. Here we extend this notion to stochastically switched systems. We refer to this type of stability as patient stability and give a simple sufficient criterium under which such systems are patiently stable, i.e. cannot be destabilised by time delays. Both criteria introduced in this paper side step the need to use Lyapunov, linear matrix inequalities, and semi-definite programming-type methods. Our examples in this paper demonstrate the simplicity of these criteria.
Periods 1 + 2 imply chaos in steep or nonsmooth maps
Authors: Jeffrey Mike R , Avrutin Viktor
Published: October 2022

Maps with discontinuities can be shown to have many of the same properties of continuous maps if we include hidden orbits—solutions that include points lying on a discontinuity. We show here how the well known property that ‘period 3 implies chaos’ also applies to maps with discontinuities, but with a twist, namely that if a map has a hidden fixed point and a hidden period 2 orbit, then it has hidden orbits of all periods, or concisely ‘period 1 + 2 implies chaos’. More precisely we show that for a one-dimensional map defined on an interval, if there exist hidden orbits of periods p and q, then there exist hidden orbits of all periods ap + bq, for any

a
,
b
∈
N

. To better understand this result we show that, by smoothing or ‘regularising’ across the discontinuity, these hidden orbits become regular unstable orbits, and the familiar results for continuous maps (like ‘period 3 implies chaos’) are restored. We also show examples of hidden orbits in some applications of oscillators, and consider how these results can be used to approximate the behaviour of continuous maps with steep segments.
Development and validation of an iodine plasma model for gridded ion thrusters
Authors: Lafleur T , Habl L , Rossi E Zorzoli , Rafalskyi D
Published: October 2022

Iodine is emerging as an attractive alternative propellant to xenon for several electric propulsion technologies due to its significantly lower cost and its ability to be stored unpressurized as a solid. Because of the more complex reaction processes and energy-loss channels in iodine plasmas however, as well as the historical lack of reliable collision cross-section data, the development of accurate theoretical and numerical models has been hindered. Using recently calculated theoretical cross-sections, we present an iodine plasma model and perform a comparison with experimental data obtained from an iodine-fuelled gridded ion thruster. The model is in reasonable agreement with experimental measurements of the ion beam current, propellant mass utilization efficiency, and ion beam composition, and is able to quantitatively and qualitatively reproduce system behaviour as the input mass flow rate and RF power are varied. In addition, both the model and experiment show that the use of iodine can lead to a performance enhancement when compared with xenon. This occurs because of the combination of different iodine reaction processes, collision cross-section values, and inelastic energy thresholds which result in lower collisional energy losses, as well as an increased antenna-plasma power transfer efficiency for thrusters using a radio-frequency inductive coil.
Evaluation of a vascularized, self-healing structure fabricated via material extrusion
Authors: Turicek Jack , Kowal Eirene , Holland Kyle , Kalchik Dylan , Stowe Jonathan , Hart Kevin
Published: October 2022

Material extrusion is a versatile 3D-printing platform for building complex one-off designs. However, the mechanical properties of parts printed using material extrusion are limited by the weak bonding between successive layers of the print, causing premature failure at these critical locations. In this work, an additively manufactured component is crafted which incorporates internal vascular channels capable of autonomously delivering a one-part healing agent to the site of interlaminar damage, when and where it occurs thereby restoring the base structure. The effectiveness of fracture toughness restoration was investigated for various healing times and healing agents. Healing efficiencies of greater than 100% are reported for experimental-type samples using acetone as the healing agent while control specimens using a non-solvent agent demonstrated no recovery. Fractography of damaged surfaces via optical imaging and scanning electron microscopy revealed multiple healing mechanisms that are discussed herein. Lastly, biological analogies and the viability of our design in application are discussed.
Observation of unconventional proximity induced superconducting effects in Bi2Se3 flakes
Authors: Yadav Reena , Bhattacharyya Biplab , Pandey Animesh , Kaur Mandeep , Gupta Anurag , Husale Sudhir
Published: October 2022

Topological superconductors (TSCs) are the materials with superconducting gap in bulk and exotic quasiparticles form gapless edge state. These quasiparticles can be employed as topological quantum bits for execution of quantum computation. Intrinsic TSCs are very rare in nature but artificial TSCs can be engineered by combining topological insulators with s-wave conventional superconductors. Hence recently hybrid structure composed of topological insulator and superconductor has been subject of research in condensed matter physics. In this paper, we use Bi2Se3 topological insulator thin flakes and tungsten (W) superconducting electrodes are deposited by using FIB based gas injection system (GIS). Fabricated Bi2Se3 flake/W hybrid structures were used to investigate induced superconductivity in Bi2Se3 flake via electric transport measurements. The resistance of the flake shows a drastic and significant decrease (8.4%) when the electrodes become superconducting. The superconducting transition (8.4%) is observed even though the length of Bi2Se3 flake between the superconducting contacts was 1.38 μm (≫ superconducting coherence length). Surprisingly, we find that resistance of Bi2Se3 flake shows an abrupt increase just before the transition temperature of superconducting electrodes (T < Tc) due to presence of electron-electron interaction. We also observe that the magnetoresistance of the flake is negative below transition temperature (T < Tc), but above transition temperature (T > Tc) magnetoresistance becomes positive due to the effects of superconducting electrodes which we discussed here in detail and it may help in constructing the topological superconductor.
ALP dark matter from kinetic fragmentation: opening up the parameter window
Authors: Eröncel Cem , Sato Ryosuke , Servant Géraldine , Sørensen Philip
Published: October 2022

The main mechanism responsible for Axion-Like-Particle (ALP) production in the early universe is the so-called misalignment mechanism. Three regimes have been investigated in this context: standard misalignment, large misalignment and kinetic misalignment. The latter applies if the axion inherits a large initial velocity in the early universe, such that the field rolls through many wiggles during its evolution, before it gets trapped in one minimum. This largely opens the region of parameter space for ALP dark matter towards higher values for the axion-photon coupling, which can be probed by the whole set of next decade's upcoming experiments. In fact, almost the entire parameter space in the [mass, decay constant] plane can now accommodate dark matter. In this paper, we show that in kinetic misalignment, the axion field is almost always entirely fragmented, meaning that the energy density of the homogeneous field is redistributed over higher-mode axions. We present a general model-independent analytical description of kinetic fragmentation, including discussion of the modified initial conditions for the mode functions due to the axion's initial velocity, and how they impact the growth of the adiabatic fluctuations. We calculate precisely the parameter regions corresponding respectively to standard misalignment, kinetic misalignment with weak fragmentation, fragmentation after trapping and fragmentation before trapping. While axion fragmentation can impact the precise determination of the relic abundance, another main observational implication is the formation of much denser compact axion halos, that is described in a companion paper. We also point out a new gravitational-wave signature that arises in the large misalignment regime with complete fragmentation and could be seen in measurements ofμdistortions in the Cosmic Microwave Background.
Post-inflationary dark matter bremsstrahlung
Authors: Mambrini Yann , Olive Keith A. , Zheng Jiaming
Published: October 2022

Dark matter may only interact with the visible sector efficiently at energy
scales above the inflaton mass, such as the Planck scale or the grand unification scale. In such
a scenario, the dark matter is mainly produced out of equilibrium during the period of reheating,
often referred to as UV freeze-in. We evaluate the abundance of the dark matter generated from
bremsstrahlung off the inflaton decay products assuming no direct coupling between the inflaton
and the dark matter. This process generally dominates the production of dark matter for low
reheating temperatures where the production through the annihilations of particle in the thermal
plasma becomes inefficient. We find that the bremsstrahlung process dominates for reheating
temperatures T
RH ≲ 1010 GeV, and produces the requisite density of dark matter for a
UV scale ≃ 1016 GeV. As examples, we calculate numerically the yield of the dark
matter bremsstrahlung through gravitation and dimension-6 vector portal effective interactions.
Long-term Photometric Study of the Pre-main Sequence Star V1180 Cas
Authors: Mutafov Asen , Semkov Evgeni , Peneva Stoyanka , Ibryamov Sunay
Published: October 2022

In this paper results from the optical photometric observations of the pre-main sequence star V1180 Cas are reported. The star is a young variable associated with the dark cloud Lynds 1340, located at a distance of 600 pc from the Sun in the star-forming region in Cassiopeia. V1180 Cas shows large amplitude variability, interpreted as a combination of accretion-induced and extinction-driven effects. Our data from VRI CCD photometric observations of the star were collected from September 2011 to February 2022. During our monitoring, we recorded several brightness dips with large amplitudes of up to 5 mag (I band). At the same time, increases in brightness over periods of several weeks have also been recorded. In this paper, we compare the photometric data obtained for V1180 Cas with observations of other low-mass pre-main sequence objects.
Experimental study on boron distribution and transport at plasma-facing components during impurity powder dropping in the Large Helical Device
Authors: Kawate T. , Ashikawa N. , Goto M. , Oishi T. , Kawamoto Y. , Toyoda H. , Shoji M. , Kawamura G. , Masuzaki S. , Nespoli F. , Gilson E.P. , Lunsford R. , Suzuki C. , Nagy A. , Gates D.
Published: October 2022

Toward real-time wall conditioning, impurity powder dropping experiments with boron powder were performed in the 22nd experimental campaign of the Large Helical Device. To examine the deposition and desorption process of boron, we focus on boron hydride (BH) molecules which presumably populate near plasma-facing components. We performed spatially-resolved spectroscopic measurements of emission by boron ions and BH molecules. From the measurement, we found that BH and B+ were concentrated on the divertor viewing chord, which suggest boron deposition in the divertor region. By comparing Hγ emissions with and without boron injection, neutral hydrogen shows uniform reduction in the SOL region, whereas less reduction of neutral hydrogen is confirmed in the divertor region. Although emissions from BH and B+ increased linearly, emissions by B0 and B4+ became constant after the middle of the discharge. Continuous reduction of carbon density in the core plasma was confirmed even after B0 and B4+ became constant. The results may show reduction of hydrogen recycling and facilitation of impurity gettering by boron in the divertor region and thus effective real-time wall conditioning.
Temperature transitions and degeneracy in the control of small clusters with a macroscopic field
Authors: Boccardo Francesco , Pierre-Louis Olivier
Published: October 2022

We present a numerical investigation of the control of few-particle fluctuating clusters with a macroscopic field. Our goal is to reach a given target cluster shape in minimum time. This question is formulated as a first passage problem in the space of cluster configurations. We find the optimal policy to set the macroscopic field as a function of the observed shape using dynamic programming. Our results show that the optimal policy is non-unique, and its degeneracy is mainly related to symmetries shared by the initial shape, the force and the target shape. The total fraction of shapes for which optimal choice of the force is non-unique vanishes as the cluster size increases. Furthermore, the optimal policy exhibits a discrete set of transitions when the temperature is varied. Each transition leads to a discontinuity in the derivative of the time to reach with target with respect to temperature. As the size of the cluster increases, the change in the policy due to temperature transitions grows like the total number of configurations and a continuum limit emerges.
Bandpass/bandstop switching with tunable pass band operation based on split ring and open loop resonators
Authors: Ibrahim Ahmed A. , Ali Wael A.E. , Mohamed Hesham A.
Published: October 2022

In this work, a bandpass filter (BPF) using a split ring and
open-loop resonators for wireless applications is discussed. The
split-ring resonator (SRR) is the main part of the band stop filter
(BSF) as a preliminary design for obtaining a band stop
behavior. The proposed filter is printed on a RO4003 substrate with
a 3.55 dielectric constant and a total size of
30 × 30 × 0.813 mm3. First, the SRR BSF is
presented to operate at a center frequency of 5 GHz then an open
loop resonator is added between input/output ports to achieve an
extra band stop region to generate a bandpass behaviour between the
two stopbands at 3.5 GHz. The PIN diodes are used to switch between
the bandstop and bandpass operation. Then, two varactor diodes are
embedded in the open-loop resonator to control the bandpass and
bandstop regions of the suggested filter. The experimental results
validate the simulated ones confirming the suitability of the
suggested filter for proper operations in different wireless
applications.
Carbon flux estimates are sensitive to data source: a comparison of field and lab temperature sensitivity data
Authors: Patel Kaizad F , Bond-Lamberty Ben , Jian Jinshi , Morris Kendalynn A , McKever Sophia A , Norris Cooper G , Zheng Jianqiu , Bailey Vanessa L
Published: October 2022

A large literature exists on mechanisms driving soil production of the greenhouse gases CO2 and CH4. Although it is common knowledge that measurements obtained through field studies vs. laboratory incubations can diverge because of the vastly different conditions of these environments, few studies have systematically examined these patterns. These data are used to parameterize and benchmark ecosystem- to global-scale models, which are then susceptible to the biases of the source data. Here, we examine how greenhouse gas measurements may be influenced by whether the measurement/incubation was conducted in the field vs. laboratory, focusing on CO2 and CH4 measurements. We use Q
10 of greenhouse gas flux (temperature sensitivity) for our analyses because this metric is commonly used in biological and Earth system sciences and is an important parameter in many modeling frameworks. We predicted that laboratory measurements would be less variable, but also less representative of true field conditions. However, there was greater variability in the Q
10 values calculated from lab-based measurements of CO2 fluxes, because lab experiments explore extremes rarely seen in situ, and reflect the physical and chemical disturbances occurring during sampling, transport, and incubation. Overall, respiration Q
10 values were significantly greater in laboratory incubations (mean = 4.19) than field measurements (mean = 3.05), with strong influences of incubation temperature and climate region/biome. However, this was in part because field measurements typically represent total respiration (Rs), whereas lab incubations typically represent heterotrophic respiration (Rh), making direct comparisons difficult to interpret. Focusing only on Rh-derived Q
10, these values showed almost identical distributions across laboratory (n = 1110) and field (n = 581) experiments, providing strong support for using the former as an experimental proxy for the latter, although we caution that geographic biases in the extant data make this conclusion tentative. Due to a smaller sample size of CH4
Q
10 data, we were unable to perform a comparable robust analysis, but we expect similar interactions with soil temperature, moisture, and environmental/climatic variables. Our results here suggest the need for more concerted efforts to document and standardize these data, including sample and site metadata.
Existence of the transfer matrix for a class of nonlocal potentials in two dimensions
Authors: Loran Farhang , Mostafazadeh Ali
Published: October 2022

Evanescent waves are waves that decay or grow exponentially in regions of the space void of interaction. In potential scattering defined by the Schrödinger equation,

(
−

∇
2

+
v
)
ψ
=

k
2

ψ

for a local potential v, they arise in dimensions greater than one and are generally present regardless of the details of v. The approximation in which one ignores the contributions of the evanescent waves to the scattering process corresponds to replacing v with a certain energy-dependent nonlocal potential

V

k

ˆ

. We present a dynamical formulation of the stationary scattering for

V

ˆ

k

in two dimensions, where the scattering data are related to the dynamics of a quantum system having a non-self-adjoint, unbounded, and nonstationary Hamiltonian operator. The evolution operator for this system determines a two-dimensional analog of the transfer matrix of stationary scattering in one dimension which contains the information about the scattering properties of the potential. Under rather general conditions on v, we establish the strong convergence of the Dyson series expansion of the evolution operator and prove the existence of the transfer matrix for

V

ˆ

k

as a densely-defined operator acting in

C

2

⊗

L
2

(
−
k
,
k
)

.
Epistemic excuses and the feeling of certainty
Authors: Vollet Jacques-Henri
Published: October 2022

Is knowledge the epistemic norm of action and assertion? Gettier and justified-false-belief cases have been raised as counterexamples to the necessity direction of that claim. Most knowledge normers reply by distinguishing permissibility from excusability. An important objection to this move, however, is that it requires a still lacking view of epistemic excuses sufficiently general to cover all the cases, correctly relating the supposed excuse to the subject’s cognitive life, and not collapsing into an account of the fundamental normative standard (see Gerken’s On Folk Epistemology, 2017). In this paper, I rely on independent work in epistemology and cognitive science to suggest a novel account of epistemic excuses in terms of epistemic feelings. In contrast to other existing accounts, this account is immune from the above objection and can thus be used to rescue the knowledge norm.
Top-down control of the left visual field bias in cued visual spatial attention
Authors: Meyyappan Sreenivasan , Rajan Abhijit , Mangun George R , Ding Mingzhou
Published: October 2022

A left visual field (LVF) bias in perceptual judgments, response speed, and discrimination accuracy has been reported in humans. Cognitive factors, such as visual spatial attention, are known to modulate or even eliminate this bias. We investigated this problem by recording pupillometry together with functional magnetic resonance imaging (fMRI) in a cued visual spatial attention task. We observed that (i) the pupil was significantly more dilated following attend-right than attend-left cues, (ii) the task performance (e.g. reaction time [RT]) did not differ between attend-left and attend-right trials, and (iii) the difference in cue-related pupil dilation between attend-left and attend-right trials was inversely related to the corresponding difference in RT. Neuroscientically, correlating the difference in cue-related pupil dilation with the corresponding cue-related fMRI difference yielded activations primarily in the right hemisphere, including the right intraparietal sulcus and the right ventrolateral prefrontal cortex. These results suggest that (i) there is an asymmetry in visual spatial attention control, with the rightward attention control being more effortful than the leftward attention control, (ii) this asymmetry underlies the reduction or the elimination of the LVF bias, and (iii) the components of the attentional control networks in the right hemisphere are likely part of the neural substrate of the observed asymmetry in attentional control.