bluuebunny/crossref_metadata_2025 huggingface dataset:
Sympathetically cooled highly charged ions in a radio-frequency trap with superconducting magnetic shielding
Authors: Dijck Elwin A. , Warnecke Christian , Wehrheim Malte , Henninger Ruben B. , Eff Julia , Georgiou Kostas , Graf Andrea , Kokh Stepan , Kozhiparambil Sajith Lakshmi P. , Mayo Christopher , Schäfer Vera M. , Volk Claudia , Schmidt Piet O. , Pfeifer Thomas , Crespo López-Urrutia José R.
Published: August 2023

We sympathetically cool highly charged ions (HCI) in Coulomb crystals of Doppler-cooled Be+ ions confined in a cryogenic linear Paul trap that is integrated into a fully enclosing radio-frequency resonator manufactured from superconducting niobium. By preparing a single Be+ cooling ion and a single HCI, quantum logic spectroscopy toward frequency metrology and qubit operations with a great variety of species are enabled. While cooling down the assembly through its transition temperature into the superconducting state, an applied quantization magnetic field becomes persistent, and the trap becomes shielded from subsequent external electromagnetic fluctuations. Using a magnetically sensitive hyperfine transition of Be+ as a qubit, we measure the fractional decay rate of the stored magnetic field to be at the 10−10 s−1 level. Ramsey interferometry and spin-echo measurements yield coherence times of >400 ms, demonstrating excellent passive magnetic shielding at frequencies down to DC.
Tipping in complex systems under fast variations of parameters
Authors: Pavithran Induja , Midhun P. R. , Sujith R. I.
Published: August 2023

Abrupt changes in the state of a system are often undesirable in natural and human-made systems. Such transitions occurring due to fast variations of system parameters are called rate-induced tipping (R-tipping). While a quasi-steady or sufficiently slow variation of a parameter does not result in tipping, a continuous variation of the parameter at a rate greater than a critical rate results in tipping. Such R-tipping would be catastrophic in real-world systems. We experimentally demonstrate R-tipping in a real-world complex system and decipher its mechanism. There is a critical rate of change of parameter above which the system undergoes tipping. We discover that there is another system variable varying simultaneously at a timescale different from that of the driver (control parameter). The competition between the effects of processes at these two timescales determines if and when tipping occurs. Motivated by the experiments, we use a nonlinear oscillator model, exhibiting Hopf bifurcation, to generalize such type of tipping to complex systems where multiple comparable timescales compete to determine the dynamics. We also explain the advanced onset of tipping, which reveals that the safe operating space of the system reduces with the increase in the rate of variations of parameters.
Polymer drag reduction: A review through the lens of coherent structures in wall-bounded turbulent flows
Authors: Saeed Zeeshan , Elbing Brian R.
Published: August 2023

The current work qualitatively surveys the phenomenon of polymer drag reduction from the standpoint of the salient coherent motions in the near-wall region of wall-bounded turbulent flows. In an attempt to make the work self-containing, turbulence is introduced phenomenologically in terms of the scale separation concept. In concert with this theme, the idea of drag crisis is then developed in terms of reduction in this scale separation. Leveraging such a perspective, it is explained how the polymer chain dynamics spatiotemporally modulate the near-wall structure of turbulent boundary layers to affect drag reduction. To this end, a sea of literature pertaining to coherent motions in Newtonian wall-bounded flows is juxtaposed with the turbulence-inhibiting characteristics of polymer chains to develop a polymer-modified version for the near-wall cycle of turbulence generation and its sustenance. The future of polymer drag reduction, in light of the current state of knowledge and contemporary challenges, is also discussed.
Nonlinearly tunable Fano resonance in photonic crystal heterostructure with embedded a varactor-loaded split ring resonator
Authors: Gao Lei , Yang Lei , Jiang Rui , Ding Yaqiong , Fang Yu , Wu Xingzhi , Ran Jia , Wu Qian , Sun Yong , Chen Yongqiang
Published: August 2023

The study explores the Fano-type interference effect in a microstrip photonic crystal (PC) heterostructure integrated with a varactor-loaded split ring resonator (SRR), both experimentally and numerically. This effect capitalizes on the PC heterostructure’s ability to provide a broad continuous spectrum, while the embedded SRR offers a narrow discrete pathway. Through coherent interference between these elements, a sharp asymmetric Fano-type transmission spectrum emerges, accompanied by a notable group delay. Furthermore, the composite configuration exhibits an electric field enhancement at the Fano resonant frequency, enhancing the nonlinear sensitivity of the transmission spectrum. The nonlinear tunability of the Fano resonance is demonstrated by applying distinct input powers, allowing for the realization of a high-performance bistable electromagnetic switch and diode in the microwave regime. The proposed configuration exhibits key features such as significant transmission contrast, low threshold intensity, and relatively high transmission amplitude, all within a compact device volume, thanks to the Fano resonant mechanism in the PC heterostructure. This design paves the way for the implementation of active metamaterials-assisted components in micro- or nano-photonic circuits, with potential applications in advanced optical devices.
The effect of the cell tilting on the temperature oscillation in turbulent Rayleigh–Bénard convection
Authors: Chen Xin , Xu Ao , Xia Ke-Qing , Xi Heng-Dong
Published: August 2023

We experimentally studied the effect of cell tilting on the temperature oscillation in turbulent Rayleigh–Bénard convection. We simultaneously measured the temperature using both in-fluid and in-wall thermistors for Ra=1.7×109 and 5.0×109 at Prandtl number Pr = 5.3. The tilt angles relative to gravity are set to 0°, 0.5°, 1°, 2°, and 7°. It is found that the temperature oscillation intensity measured in-fluid is much stronger than that measured in-wall, because the in-fluid thermistors measure both the large-scale circulation (LSC) and the plumes/plume clusters, while the in-wall thermistors only measure the LSC due to the filter effect of the sidewall. Despite the intensity difference, the obtained azimuthal profiles of the oscillation intensity measured by in-fluid and in-wall share similar spatial distribution, and the spatial distribution can be explained by the torsional motion near the top and bottom plates and the sloshing motion at the mid-height. With the in-fluid measurements, we find that with the increase in the tilt angle, the azimuthal profile of oscillation evolves toward a sawtooth-like profile and the intensity gets more prominent, which implies that the temperature oscillation becomes more coherent. Through a conditional sampling method based on the azimuthal position of LSC, we reveal that the uniformly distributed oscillation intensity in the level cell is the result of the superimposition of the random azimuthal motion and the sloshing motion. Tilting the cell can efficiently disentangle the above-mentioned two types of motions of LSC. Moreover, we found that the frequency of the temperature oscillation increases when the tilt angle increases, while the amplitude of the sloshing motion of the LSC remains unchanged, which is believed to be related to the confinement of the convection cell.
Development of a 3-D-printable device for continuous measuring of heavy metal ion concentrations
Authors: de Villiers Charl , Wajrak Magdalena , Lubansky Alex
Published: August 2023

Three-dimensional (3-D) printing offers the potential to create a range of tailored devices within many different industrial facilities. In this article, devices were designed and fabricated using 3-D printing to house electrodes for the testing of heavy metal concentration in hazardous fluids, particularly for biological samples such as urine or blood. The devices, connected to a syringe pump, were shown to be able to be operated without leaking. Proof of concept experiments were performed using Anodic Stripping Voltammetry (ASV) methods, demonstrating that the devices are able to be used for quick, cheap testing, showing the potential of the technique as a more hygienic analysis technique than conventional ASV with an immediacy that standard techniques such as inductively coupled plasma mass spectrometry (ICP-MS) do not offer. With further development and validation, 3-D-printed ASV techniques may provide a robust, reliable and affordable solution for heavy metal concentration detection in remote locations.
Delivery of a bespoke parasitology subject in an alternative online realm: lessons and lasting innovations
Authors: Clarke Daniel T. W. , Jabbar Abdul , Waller Karena L
Published: August 2023

In the second semester of 2020, despite the need to pivot to online learning in response to the COVID-19 pandemic, our academic teaching team commenced the delivery of a brand-new, bespoke parasitology subject to third year Bachelor of Biomedicine and Bachelor of Science students at The University of Melbourne. This purposefully designed subject, ‘Medical Microbiology: Parasitology’, was developed in collaboration with internationally renowned parasitologists and global health researchers to take a broad, multi-disciplinary approach to student learning and introduced students to the exciting, complex and diverse world of medically important parasites, including key examples of protists, helminths and arthropods. We also attempted to enhance the student experience during the online delivery of lectures, practical classes and active learning sessions by implementing synchronous and asynchronous approaches to increase engagement. This included weekly newsletters, in-class interactions by Zoom chat and polling platforms, moderated discussion boards, online drop-in sessions, authentic learning workshops and formative feedback quizzes. Although some engagement methods were not as successful as we had hoped, others proved to be instrumental in increasing supportive learning, as indicated by student attendance at online sessions, and the general sentiments observed from various student feedback mechanisms. Consequently, these strategies will continue to be incorporated as we shape the subsequent iterations of this, and other subjects, in a post-COVID world.
Rationally designed chimeric PI3K-BET bromodomain inhibitors elicit curative responses in MYC-driven lymphoma
Authors: Oh Danielle H. , Ma Xiao , Hogg Simon J. , He Jackson , Kearney Conor , Brasacchio Daniella , Susanto Olivia , Maher Belinda , Jennings Ian G. , Newbold Andrea , Fraser Peter , Gruber Emily , Kats Lev M. , Gregory Gareth P. , Johnstone Ricky W. , Thompson Philip E. , Shortt Jake
Published: August 2023

Targeted inhibitors of bromodomain and extraterminal (BET)-bromodomains and phosphatidylinositol-3-kinase (PI3K) signaling demonstrate potent but self-limited antilymphoma activity as single agents in the context of cellular Myelocytomatosis (
cMYC
) oncogene-dysregulation. However, combined PI3K and BET inhibition imparts synergistic anticancer activity with the potential for more sustained disease responses due to the mutual antagonism of compensatory epigenetic and signaling networks. Here, we describe the mechanistic and therapeutic validation of rationally designed dual PI3K/BET bromodomain inhibitors, built by linkage of established PI3K and BET inhibitor pharmacophores. The lead candidate demonstrates high selectivity, nanomolar range cellular potency, and compelling in vivo efficacy, including curative responses in the aggressive Eµ-
Myc
lymphoma model. These studies further support the therapeutic strategy of combined PI3K and BET inhibition and provide a potential step-change in approach to orthogonal MYC antagonism using optimized chimeric small-molecule technology.
Using kinetics to avoid sigma phase formation on hyper duplex stainless weld cladding
Authors: Acuna Andres , Ramirez Antonio , Riffel Kaue Correa
Published: August 2023

The Hyper Duplex Stainless Steel HDSS enhanced corrosion resistance and toughness relies upon high alloying to obtain a balanced ferrite and austenite volume and pitting resistance equivalent number PREn. However, during welding, sigma phase precipitates might form, hindering corrosion and mechanical performance. Therefore, a kinetics model is developed to avoid the sigma phase's formation during welding and validated using physical simulation, finite element analysis (FEA), welding, and SEM characterisation. The sigma phase kinetics model produced calculated and validated temperature-time-transformation (TTT) and continuous-cooling-transformation (CCT) curves from which a 4°C/s cooling rate was found as a cooling rate threshold for sigma phase formation in this new material. Three-layered gas tungsten arc welding GTAW cladded mockup with 53 beads produced 24°C/s minimum cooling rate. Moreover, microscopy, mechanical, and corrosion testing attested it as a sigma-free weld.
EEF2-inactivating toxins engage the NLRP1 inflammasome and promote epithelial barrier disruption
Authors: Pinilla Miriam , Mazars Raoul , Vergé Romain , Gorse Leana , Paradis Margaux , Suire Bastien , Santoni Karin , Robinson Kim Samirah , Toh Gee Ann , Prouvensier Laure , Leon-Icaza Stephen Adonai , Hessel Audrey , Péricat David , Murris Marlène , Guet-Revillet Hélène , Henras Anthony , Buyck Julien , Ravet Emmanuel , Zhong Franklin L. , Cougoule Céline , Planès Rémi , Meunier Etienne
Published: August 2023

Human airway and corneal epithelial cells, which are critically altered during chronic infections mediated by Pseudomonas aeruginosa, specifically express the inflammasome sensor NLRP1. Here, together with a companion study, we report that the NLRP1 inflammasome detects exotoxin A (EXOA), a ribotoxin released by P. aeruginosa type 2 secretion system (T2SS), during chronic infection. Mechanistically, EXOA-driven eukaryotic elongation factor 2 (EEF2) ribosylation and covalent inactivation promote ribotoxic stress and subsequent NLRP1 inflammasome activation, a process shared with other EEF2-inactivating toxins, diphtheria toxin and cholix toxin. Biochemically, irreversible EEF2 inactivation triggers ribosome stress–associated kinases ZAKα- and P38-dependent NLRP1 phosphorylation and subsequent proteasome-driven functional degradation. Finally, cystic fibrosis cells from patients exhibit exacerbated P38 activity and hypersensitivity to EXOA-induced ribotoxic stress–dependent NLRP1 inflammasome activation, a process inhibited by the use of ZAKα inhibitors. Altogether, our results show the importance of P. aeruginosa virulence factor EXOA at promoting NLRP1-dependent epithelial damage and identify ZAKα as a critical sensor of virulence-inactivated EEF2.
Analysis of the discrepancy principle for Tikhonov regularization with oversmoothing penalty term under low order source conditions
Authors: Klinkhammer C , Plato R
Published: August 2023

We study the application of Tikhonov regularization to ill-posed nonlinear operator equations. The objective of this work is to prove convergence rates for the discrepancy principle under low order source conditions of logarithmic type. We work within the framework of Hilbert scales and extend existing studies on this subject to the oversmoothing case. The latter means that the exact solution of the treated operator equation does not belong to the domain of definition of the penalty term. As a consequence, the Tikhonov functional fails to have a finite value.
Computer vision assisted decomposition analysis of atom probe tomography data
Authors: Sälker Janis A , Hadian Raheleh , Schneider Jochen M , Hans Marcus
Published: August 2023

While atom probe tomography (APT) offers 3D spatially-resolved compositional characterization at the nanometer scale, individual inspection of large datasets is time demanding and the interpretation thereof is highly operator-dependent. Recently, the decomposition behavior of (V,Al)N thin films was investigated by APT. The conventional analysis, employing standard tools from commercial software, is laborious and only a small fraction (below 5%) of the total acquired data has been used. In the present work, the analysis workflow is automated, taking into account more than 90% of the total acquired data. As a first step, the decomposition products, including matrix and enriched phases, were identified via deep learning-based semantic image segmentation. Performance of the ‘matrix’ and the decomposition product ‘aluminum-rich’ was very good, achieving F1-scores of 0.994 and 0.943, respectively, while performance for ‘vanadium-rich’ was with 0.854 slightly lower. The segmentation enables the investigation of phase formation evolution over temperature. As a next step, early stages of the spinodal decomposition were probed on the ‘matrix’ phase by a neighborhood analysis. While results were consistent with prior work, the data analysis in this work is statistically more robust by leveraging an order of magnitude larger dataset. In the end, the transferability of the presented phase segmentation workflow of the (V,Al)N-based model is shown and discussed for the decomposition of isostructural (Ti,Al)N.
Two-photon absorption in colloidal semiconductor nanocrystals: a review
Authors: Alo Arthur , Lemus Jonathan C , Sousa Claudevan A , Nagamine Gabriel , Padilha Lazaro A
Published: August 2023

Large two-photon absorption (2PA) cross-section combined with high emission quantum efficiency and size-tunable bandgap energy has put colloidal semiconductor nanocrystals (NCs) on the vanguard of nonlinear optical materials. After nearly two decades of intense studies on the nonlinear optical response in quantum-confined semiconductors, this is still a vibrant field, as novel nanomaterials are being developed and new applications are being proposed. In this review, we examine the progress of 2PA research in NCs, highlighting the impact of quantum confinement on the magnitude and spectral characteristics of this nonlinear response in semiconductor materials. We show that for NCs with three-dimensional quantum confinement, the so-called quantum dots, 2PA cross-section grows linearly with the nanoparticle volume, following a universal volume scaling. We overview strategies used to gain further control over the nonlinear optical response in these structures by shape and heterostructure engineering and some applications that might take advantage of the series of unique properties of these nanostructures.
Single and multiple fault diagnosis based on PCA with relative variation of contribution strategy
Authors: Berbache Soraia , Harkat Mohamed Faouzi , Lachouri Abderrezak , Kratz Frédérik
Published: August 2023

Data-driven methods have been recognized as an efficient tool for multivariate statistical process control. Contribution plots are also well known as a popular tool in principal component analysis, which is used for isolating sensor faults without the need for any prior information. However, studies carried out in the literature have unified contribution plots in three general approaches. Furthermore, they demonstrated that correct diagnosis based on contribution plots is not guaranteed for either single or multiple sensor faults. Therefore, to deal with this issue, the present paper highlights a new contribution formula called relative variation of contribution. Simulation results show that the proposed method of contribution can successfully perform the fault isolation task, in comparison with partial decomposition contribution and its relative version (rPDC) based on their fault isolation rate.
Composite fault feature extraction of rolling bearing using adaptive circulant singular spectrum analysis
Authors: Zhou Hongdi , Zhu Lin , Zhong Fei , Cai Yijie
Published: August 2023

Aiming to extract the weak composite fault characteristics of a rolling bearing under harsh operation conditions, a novel composite fault diagnosis method for bearings based on adaptive circulant singular spectrum analysis (ACiSSA) is proposed. The proposed method is able to adaptively obtain the eigenvalue of a non-stationary vibration signal in any dimension, and effectively reassemble the same frequency components and improve the signal-to-noise ratio (SNR). Specifically, circulant singular spectrum analysis is utilized to decompose the raw signal, and the optimal parameters, i.e. the embedding dimension and threshold value of cumulative contribution, are selected to maximum kurtosis through the grey wolf optimization method. The signal is reconstructed with high SNR according to the effective singular spectrum components. Envelope demodulation analysis is then implemented to extract the characteristic defect frequency in the reconstructed signal. Finally, feature extraction performance is quantitatively evaluated, and experimental results show that the proposed ACiSSA method is able to extract more sensitive features under more noisy conditions compared with other common methods, with higher computational efficiency.
Investigation of cavitation evolvement in a pump inducer by proper orthogonal decomposition analysis of video images
Authors: Cao Ruijia , Yuan Jianping , Kong Xiangxu , Xu Zhenfa , Peng Guoyi , Qiu Ning
Published: August 2023

The aim of this study is to develop a contour extraction method for the investigation of the temporal and spatial characteristics of cavitation evolution in high-speed inducers. Cavitation experiments were conducted, and corresponding snapshots were captured using a high-speed camera subsequently. The raw images were processed while using threshold value filtering techniques to extract only relevant bubble information. Proper orthogonal decomposition was employed to explore the evolving characteristics in a quantitative manner. Results show that the cavitation evolution process is an unsteady process when viewed from the side. In high net positive suction head (NPSH) environments, multiple small-scale spatial modals contribute significantly to the effective proportion of the cavitation structure. The attached sheet cavitation exists in the blade edge which is the main embodiment of cavitation area evolvement. Under low NPSH conditions, the primary flow feature can be reflected by a low-mode flow pattern, associated with the inducer’s rotation effect. The evolving regulation of cavitation area in developed stage is closely submitted to the trigonometric function. And the exhibited spatial coefficient exposes the hidden reflux vortex feature. The proposed image separation techniques enable the quantification of morphological features, which can provide technical details for the digital design of inducers.
Investigation of the high-temperature field distribution characteristics for a multi-jet burner by OH-PLIF and coherent anti-Stokes Raman spectroscopy
Authors: Bai Bing , Qi Xinhua , Yang Wenbin , Che Qingfeng , Sun Weimin , Li Bo , Chen Shuang
Published: August 2023

The construction of a high-temperature gas calibration source is of great significance since it can provide an effective high-temperature experimental environment for, e.g. verifying high-temperature measurement techniques and studying high-temperature combustion mechanisms. Here, we try to obtain a high-temperature gas field on a multi-jet burner by controlling the gas supplies to it. We use OH planar laser-induced fluorescence (OH-PLIF) to observe the compositional uniformity of the field and coherent anti-Stokes Raman scattering (CARS) to investigate the temperature uniformity of the field. We find from OH-PLIF images that the distribution of OH between the adjacent jets becomes more uniform with the increasing flow rate of CH4, and the flow rate of the co-flow N2 around jets also affects the uniformity of OH distribution. The measured temperature distribution by CARS is consistent with the OH distribution. At the jet outlet location, the temperature distribution had a periodic variation and gradually became more uniform with the height increased from the jet outlet. We find that the flow rate of CH4 and co-flow N2 and the radiative heat transfer rate play an important role in temperature distribution for the multi-jet burner. Also, the results show that a wide range of temperatures can be constructed by regulating the recipe of the gas supplies, and the highest temperature achieved in this work is 2457 K.
Engineering the defect distribution in ZnO nanorods through laser irradiation
Authors: Zheng Shuo , Chen Zuolong , Duley Walter W , Wu Yimin A , Peng Peng , Zhou Y Norman
Published: August 2023

In recent years, defect engineering has shown great potential to improve the properties of metal oxide nanomaterials for various applications thus received extensive investigations. While traditional techniques mostly focus on controlling the defects during the synthesis of the material, laser irradiation has emerged as a promising post-deposition technique to further modulate the properties of defects yet there is still limited information. In this article, defects such as oxygen vacancies are tailored in ZnO nanorods through nanosecond (ns) laser irradiation. The relation between laser parameters and the temperature rise in the ZnO due to laser heating was established based on the observation in the SEM and the simulation. Raman spectra indicated that the concentration of the oxygen vacancies in the ZnO is temperature-dependent and can be controlled by changing the laser fluence and exposure time. This is also supported by the absorption spectra and the photoluminescence spectra of ZnO NRs irradiated under these conditions. On the other hand, the distribution of the oxygen vacancies was studied by XPS depth profiling, and it was confirmed that the surface-to-bulk ratio of the oxygen vacancies can be modulated by varying the laser fluence and exposure time. Based on these results, four distinctive regimes containing different ratios of surface-to-bulk oxygen vacancies have been identified. Laser-processed ZnO nanorods were also used as the catalyst for the photocatalytic degradation of rhodamine B (RhB) dye to demonstrate the efficacy of this laser engineering technique.
On multifractal analysis and large deviations of singular hyperbolic attractors
Authors: Shi Yi , Tian Xueting , Varandas Paulo , Wang Xiaodong
Published: August 2023

In this paper we study the multifractal analysis and large derivations for singular hyperbolic attractors, including the geometric Lorenz attractors. For each singular hyperbolic homoclinic class whose periodic orbits are all homoclinically related and such that the space of ergodic probability measures is connected, we prove that: (i) level sets associated to continuous observables are dense in the homoclinic class and satisfy a variational principle; (ii) irregular sets are either empty or are Baire generic and carry full topological entropy. The assumptions are satisfied byC1-generic singular hyperbolic attractors andCr-generic geometric Lorenz attractors(r⩾2). Finally we prove level-2 large deviations bounds for weak Gibbs measures, which provide a large deviations principle in the special case of Gibbs measures. The main technique we apply is the horseshoe approximation property.
Compact sets with large projections and nowhere dense sumset
Authors: Balka Richárd , Elekes Márton , Kiss Viktor , Nagy Donát , Poór Márk
Published: August 2023

We answer a question of Banakh, Jabłońska and Jabłoński by showing that for

d
⩾
2

there exists a compact set

K
⊆

R

d

such that the projection of K onto each hyperplane is of non-empty interior, but K + K is nowhere dense. The proof relies on a random construction. A natural approach in the proofs is to construct such a K in the unit cube with full projections, that is, such that the projections of K agree with that of the unit cube. We investigate the generalization of these problems for projections onto various dimensional subspaces as well as for

ℓ

-fold sumsets. We obtain numerous positive and negative results, but also leave open many interesting cases. We also show that in most cases if we have a specific example of such a compact set then actually the generic (in the sense of Baire category) compact set in a suitably chosen space is also an example. Finally, utilizing a computer-aided construction, we show that the compact set in the plane with full projections and nowhere dense sumset can be self-similar.
Global existence and convergence results for a class of nonlinear time fractional diffusion equation
Authors: Huy Tuan Nguyen
Published: August 2023

This paper investigates Cauchy problems of nonlinear parabolic equation with a Caputo fractional derivative. When the initial datum is sufficiently small in some appropriate spaces, we demonstrate the existence in global time and uniqueness of a mild solution in fractional Sobolev spaces using some novel techniques. Under some suitable assumptions on the initial datum, we show that the mild solution of the time fractional parabolic equation converges to the mild solution of the classical problem when

α
→

1

−

. Under some appropriate assumptions on the initial datum, we show that the mild solution of the time fractional diffusion equation converges to the mild solution of the classical problem when

α
→

1

−

. Our theoretical results can be widely applied to many different equations such as the Hamilton–Jacobi equation, the Navier–Stokes equation in two cases: the fractional derivative and the classical derivative. Our paper also provides a completely new answer to the related open problem of convergence of solutions to fractional diffusion equations as the order of fractional derivative approaches 1−.
Uniform hyperbolicity of a class of scattering maps
Authors: Yoshino Hajime , Mertig Normann , Shudo Akira
Published: August 2023

In recent years fractal Weyl laws and related quantum eigenfunction hypothesis have been studied in a plethora of numerical model systems, called quantum maps. In some models studied there one can easily prove uniform hyperbolicity. Yet, a numerically sound method for computing quantum resonance states, did not exist. To address this challenge, we recently introduced a new class of quantum maps (Mertig and Shudo 2018 Phys. Rev. E 97 042216). For these quantum maps, we showed that, quantum resonance states can numerically be computed using theoretically grounded methods such as complex scaling or weak absorbing potentials (Mertig and Shudo 2018 Phys. Rev. E 97 042216). However, proving uniform hyperbolicty for this class of quantum maps was not straight forward. Going beyond that work this article generalises the class of scattering maps and provides mathematical proofs for their uniform hyperbolicity. In particular, we show that the suggested class of two-dimensional symplectic scattering maps satisfies the topological horseshoe condition and uniform hyperbolicity. In order to prove these properties, we follow the procedure developed in the paper by Devaney and Nitecki (1979 Commun. Math. Phys.
67 137–46). Specifically, uniform hyperbolicity is shown by identifying a proper region in which the non-wandering set satisfies a sufficient condition to have the so-called sector bundle or cone field. Since no quantum map is known where both a proof of uniform hyperbolicity and a methodologically sound method for numerically computing quantum resonance states exist simultaneously, the present result should be valuable to further test fractal Weyl laws and related topics such as chaotic eigenfunction hypothesis.
The time asymptotic expansion for the compressible Euler equations with time-dependent damping
Authors: Geng Shifeng , Huang Feimin , Jin Guanghui , Wu Xiaochun
Published: August 2023

For the compressible Euler equations with time-dependent damping

−

1

(
1
+
t

)

λ

ρ
u

, we propose a time asymptotic expansion around the self-similar solution of the generalized porous media equation and rigorously justify this expansion as

λ
∈
(

1
7

,
1
)

. Furthermore, the above expansion is the best asymptotic profile of the solution to the compressible Euler equations with time-dependent damping.
A discrete ordinates Boltzmann solver for application to inverse planning of photons and protons
Authors: Bedford James L
Published: August 2023

The aim of this work is to develop a discrete ordinates Boltzmann solver that can be used for calculation of absorbed dose from both photons and protons within an inverse planning optimiser, so as to perform accurate dose calculation throughout the whole of the inverse planning process. With photons, five transport sweeps were performed to obtain scattered photon fluence, and unscattered electron fluence was then obtained and used as a fixed source for solution of the electron transport equations. With protons, continuous slowing down was treated as a fixed source, and five transport sweeps were used to calculate scattered fluence. The total electron or proton fluence was multiplied by the stopping power ratio for the transport medium to obtain absorbed dose. The method was evaluated in homogeneous media and in a lung case where the planning target volume was surrounded by low-density lung material. Photon arc, proton passive scattering and proton arc treatments were considered. The results were compared to a clinically validated convolution dose calculation for photons, and with an analytical method for protons. In water-equivalent media, the discrete ordinates method agrees with the alternative algorithms to within 2%. Convergence is found to be sufficiently complete for water-, lung- and bone-equivalent materials after five iterations. The dose calculated by the relatively simple angular quadrature is seen to be very close to that calculated by a more comprehensive quadrature. For inhomogeneous lung plans, the method shows more heterogeneity of dose to the planning target volume than the comparative methods. The discrete ordinates Boltzmann solver provides a general framework for dose calculation with both photons and protons. The method is suitable for incorporation into an inverse planning optimiser, so that accurate dose calculation in a heterogeneous medium can be obtained throughout inverse planning, with the result that the final dose distribution is as predicted by the optimiser.
Variable stiffness mechanism of flexible composite laminates implanted with modular SMAHC
Authors: Pan Wencheng , Ke Jun , Hu Yan , Wu Zhenyu
Published: August 2023

In this study, a new flexible hybrid shape memory alloy composites (SMAHCs) with a polydimethylsiloxane (PDMS) matrix containing a shape memory alloy (SMA) of a hybrid Basalt/Kevlar fiber 3D woven composite is developed. The SMAHC is implanted into a glass fiber/PDMS composite laminate in a modular manner to study the stiffness of composite plates in response to temperature. The variable stiffness theory of the SMAHC is derived, and the influence of SMA parameters on the stiffness of the SMAHC is analyzed. A three-point bending test is performed to determine the stiffness of the composite plates at multiple temperature points in the form of Joule heat driving the composite plates. The stress and temperature distributions of the composite plate are analyzed in Abaqus under a temperature-displacement coupling setting. The results shows that the SMAHC stiffness is negatively correlated with SMA fiber diameter and positively correlated with SMA fiber volume fraction. With an increase in driving temperature, the stiffness of the composite plates tends to decrease. When the end temperature of the austenitic phase transformation is reached, the high-modulus austenitic SMA slightly increase the stiffness of the composite plate. The stiffness improvement is more significant when the SMAHC is placed in the middle area of the laminate and the SMA is located in the tension area. This study may provide a reference for the design of variable stiffness SMAHC for plate composite structures.
Finite-element recipes for HTS-coated conductors and HTS tape topologies
Authors: Carvalho D J Gameiro , Ferreira da Silva F , Fernandes J F P , da Costa Branco P J
Published: August 2023

Different electromagnetic formulations were proposed and implemented in finite element (FE) software to model high-temperature superconductors-coated conductors (HTS-CCs) and HTS tape topologies. However, their modelling can be notably demanding in computational resources, particularly computation time. Mixed formulations such as

H
−
ϕ

, T − A, and

T
−
ϕ

were proposed and used, proving to be considerably faster than conventional ones, although these formulations present different performances and characteristics depending on the modelled conditions and geometry. This paper reviews the electromagnetic formulations proposed in the literature for FE simulation of HTS-coated conductors and HTS tape topologies. Implementation aspects, which are lacking in the literature, are presented, especially for T − A and

T
−
ϕ

formulations developed for most relevant tape topologies, for example, HTS CC stacked (CCS) tape and HTS twisted tapes. Simulation results are analysed, alongside the consequent conclusions regarding the accuracy, as well as advantages and limitations of each formulation, all made taking into account each tape geometry and its operating conditions. Their implementation review will be straightforward in the case of

H
−

formulation and

A
−

formulation. In advance, the T − A formulation is shown to be the most efficient FE formulation for HTS-CC topologies, being, among the studied, the most efficient computational resource. Moreover, its inherent approximation of the HTS tape as a thin sheet has delivered accurate results, specifically regarding current density distributions in the HTS layer and AC losses when compared with the

H
−

formulation. Correspondingly, FE multiphysics simulations are shown for three HTS-CC topologies: a single HTS tape, an HTS CCS tape, and an HTS twisted-stacked tape cable.
Measurement and analysis of winding stresses in dry-wound pancake coils considering nonlinear compressive behaviors
Authors: Yan Yufan , Kim Jaemin , Bong Uijong , Jang Wonseok , Kim Geonyoung , Park Jeonghwan , Hahn Seungyong
Published: August 2023

Considering coil stress management, conductor thermal stability, and susceptibility to delamination, the dry-winding approach has been gradually applied and tested in high-temperature-superconducting coils wound with REBa2Cu3O

7
−
x

(REBCO) coated conductors (CCs). In dry-wound coils, the winding tension can be a useful tool for managing the mechanical stresses and maintaining the structural stability. It is also related to the contact resistivity characteristics of no-insulation and metal-as-insulation coils. In this paper, we present a study on the winding stresses in dry-wound pancake coils considering nonlinear compressive behaviors in the radial direction. Coils wound with stainless-steel (SS) tapes and REBCO CCs were prepared, respectively, with various sizes (90–140 turns) and winding tensions (26–61 MPa). The radial pressure was obtained by applying the pressure measurement films, which cover a pressure range up to 50 MPa. A relatively moderate radial pressure buildup was observed in coils wound with SS tapes, indicating that the effective radial modulus of the coil as an entity is considerably lower compared to the tensile modulus in the azimuthal direction. This is consistent with the nonlinear stress–strain relationship of stacked thin sheets under transverse compression, which can be further explained by the contact behaviors between two rough surfaces. The average radial pressure in CC coils shared similar characteristics as that in SS coils, whereas the radial stress along the conductor edges were significantly higher compared to the middle. Cross-sectional microscopy of the CCs suggests that this can be primarily attributed to the thickness variations across the conductor width. These results suggest that the microscopic rough-surface contact and thickness variation of the wound tape play a critical role in the coil stiffness as well as the winding stress distributions.
Mean-square asymptotic synchronization of complex dynamical networks subject to communication delay and switching topology
Authors: Wang Xi , Qin Xueli , Ji Yuxiang , Jiang Taiping , Zhou Jianping
Published: August 2023

This paper addresses the issue of mean-square asymptotic synchronization (MSAS) of complex dynamical networks with communication delay and switching topology. The communication delay is assumed to be time-variant and bounded, and the switching topology is governed by a semi-Markovian process and allowed to be asymmetric. A distributed control law based on state feedback is presented. Two criteria for the MSAS are derived using a mode-dependent Lyapunov-Krasovskii functional, the Bessel-Legendre integral inequality, and a parameter-dependent convex combination inequality, for the asymmetric and symmetric topology cases, respectively. The scenario of fixed topology is also considered, for which two asymptotic synchronization criteria are proposed. Two simulation examples are provided to illustrate the effectiveness and reduced conservatism of the proposed theoretical results.
Physics based numerical model of a nanoscale dielectric modulated step graded germanium source biotube FET sensor: modelling and simulation
Authors: Das Amit , Rewari Sonam , Kanaujia Binod Kumar , Deswal S S , Gupta R S
Published: August 2023

This paper proposes a novel dielectric modulated step-graded germanium source biotube FET for label-free biosensing applications. Its integrated structure and unique design combine the benefits of the gate stack, germanium source, triple-gate architecture, and a step-graded biotube channel, resulting in superior performance over existing biosensors. A compact two-dimensional analytical model for channel potential, drain current, threshold voltage, and subthreshold swing has been formulated and agrees well with the simulated results. The comprehensive investigation of different device parameters, including doping and bias, offers valuable insights into optimizing the biosensor’s performance. The proposed biosensor exhibits remarkable sensitivity, achieving up to 263 mV and 1495.52 nA for certain biomolecules, which has been validated by a compact analytical model and simulations performed on the SILVACO TCAD simulator. Several parameters are employed to assess the biosensor’s effectiveness: threshold voltage, ION/IOFF ratio, subthreshold swing, off-current, peak trans-conductance, and on-current. Furthermore, the biotube channel design enables lightweight and cost-efficient biosensors, enhancing the biosensor’s practicality. This work also includes an analysis of the effect of temperature on the biosensor’s performance and characteristics, providing insights into practical applications. High sensitivity of the biosensor signifies a significant advancement in biosensing technology, suggesting a wide range of potential applications in biomedical field.
Shadowing corrections to the evolution of singlet structure function
Authors: Devee Mayuri
Published: August 2023

In this paper, a semi-analytical approach is introduced to address the solution of the nonlinear Gribov-Levin-Ryskin-Mueller-Qiu (GLR-MQ) evolution equation for sea quark distribution. Here the effect of gluon shadowing on the behaviour of singlet structure function,

F

2

S

(
x
,

Q

2

)

, has been investigated, particularly in the regime of small-x and moderate-Q
2. The predicted values of singlet structure functions with shadowing corrections align well with different experimental data and existing parametrizations. It is very fascinating to observe signatures of gluon recombination within these predictions. Notably, as x decreases, the rapid growth of singlet structure function is eventually tamed by the shadowing or nonlinear term appeared in the QCD evolution due to gluon recombination. This taming behaviour of shadowing singlet structure function towards small-x become significant at the hot spots, at R = 2 GeV−1. Further the computed ratios of

F

2

S

(
x
,

Q

2

)

with shadowing, in comparison to those without shadowing, clearly indicate that towards smaller values of x and Q
2 the nonlinear effects gradually become prominent.
Vector wave solutions in electrodynamics: the Heaviside-Larmor symmetry and tiered potential invariance
Authors: Fernández-Guasti M
Published: August 2023

The tiered symmetric structure of the electromagnetic equations, in particular the Heaviside Larmor (HL) symmetry, is used to obtain vector wave solutions of the wave equation obtained from Maxwell's equations. In this HL vector solutions procedure (HL-VS), the seed vector need not be constant but must satisfy an inhomogeneous Helmholtz equation. This seed can be used either to obtain the polarization basis in a given coordinate system or a particular polarization state. The spherical vector waves (SVW) basis is economically derived retaining the physical meaning throughout the procedure. Examples of low order modes are expounded. The cylindrical vector wave basis is also derived and particular polarization states are compared with previous results. Plane waves are used to elucidate the HL symmetry terms and their controlled manipulation in order to tailor specific structured light states. The angular momentum of plane waves with elliptical polarization is obtained. The controversy as to whether circularly polarized plane waves carry angular momentum is answered in the affirmative.
A 2D steady state analytical model for atmospheric pressure RF plasma jet
Authors: Mahreen  , Ganguli A , Prakash G Veda , Kar Satyananda , Sahu Debaprasad
Published: August 2023

This paper presents a 2-dimensional analytical model for plasma inside the discharge tube of an RF atmospheric pressure plasma jet (APPJ) in coaxial geometry. Since the model is a steady state one, it requires that the frequency of the applied RF be high enough so that the formation of streamers and plasma bullets is suppressed and that continuous plasma is present throughout the RF cycle. It is also assumed that power absorption is due to electron-atom collisions in the bulk plasma. The model takes into account gas flow, yielding a flow-diffusion axial flux that aids the exit of the plasma into the atmosphere. The inputs to the model are the reactor dimensions, average power fed (P

av
) and the flow velocity of the gas (ug) using which the model yields the plasma density along with its radial and axial profiles, electron temperature, axial and radial particle fluxes, gas heating, flux, and energy of the plasma particles escaping from the discharge tube into the ambient air. Experiments were undertaken on an RF-powered jet at 13.56 MHz. Substituting the average RF power, measured using voltage and current probes, into the model gives the plasma density n ≈ 3.9 × 1017(≅2.8 × 1019)m−3 at

P

av

≅
10
W

≅
8
W

for He (Ar). The corresponding electron temperature given by the model is

T

e

≈

1.8

≈
0.8

eV
,

for He (Ar). It is hoped that the developed model would be able to provide a comprehensive methodology for analyzing APPJs.