bluuebunny/crossref_metadata_2025 huggingface dataset:
Carpal Tunnel Release Performed during Distal Radius Fracture Surgery
Authors: Rothman Alyssa , Samineni Aneesh V. , Sing David C. , Zhang Joanne Y. , Stein Andrew B.
Published: November 2022

Background Carpal tunnel release (CTR) may be concomitantly performed along with distal radius fracture open reduction internal fixation (DRF ORIF) to prevent carpal tunnel syndrome; however, there is little to no literature investigating the rate, risk factors, and complications associated with CTR.

Questions/Purposes The purpose was to determine (1) the rate of CTR performed at time of DRF ORIF, (2) factors associated with CTR, and (3) whether CTR was associated with any complications.

Patients and Methods In this case-control study, adult patients who underwent DRF ORIF from 2014 to 2018 were identified from a national surgical database. Two cohorts were analyzed, (1) patients with CTR and (2) patients without CTR. Preoperative characteristics and postoperative complications were compared with determine factors associated with CTR.

Results Of the 18,466 patients, 769 (4.2%) had CTR. Rates of CTR in patients with intra-articular fractures with two or three fragments were significantly higher than the rate of CTR for patients with extra-articular fractures. Underweight patients underwent CTR at a significantly lower rate compared with overweight and obese patients. The American Society of Anesthesiologists ≥3 was associated with a higher rate of CTR. Male and older patients were less likely to have CTR.

Conclusion The rate of CTR at time of DRF ORIF was 4.2%. Intra-articular fractures with multiple fragments were strongly associated with CTR at time of DRF ORIF, while being underweight, elderly, and male were associated with lower rates of CTR. These findings should be considered when developing clinical guidelines to assess the need for CTR in patients undergoing DRF ORIF. This is a retrospective case control study and reflects level of evidence III.
Clinical Results of Arthroscopic Resection of Dorsal Wrist Ganglion with a Minimum of 3 Years Follow-up
Authors: Saremi Hossein , bolbanabad Mohammad Mohammadi , Abdollahian Amir Reza , Mohammadi Younes
Published: November 2022

Introduction Ganglion cysts are the most common benign tumors of the wrist. Their arthroscopic resection is becoming common. However, there are a limited number of studies comparing arthroscopic and open surgeries. This study evaluated the subjective and objective results of arthroscopy with a minimum of 3 years follow-up.

Patients and Methods Patients with dorsal wrist ganglion who underwent arthroscopic ganglionectomy were evaluated regarding pain (using visual analog scale) and satisfaction as subjective results. We also evaluated their scar (with the Vancouver scar scale), range of motion, and recurrence as objective results.

Results There were 20 patients in the study. Mean of follow-up time was 52.5 months. Recurrence rate was 5%, and visual analog scale of pain decreased from 3.7 to 0.5 at the final follow-up. Sixteen patients were completely satisfied, three patients were partially satisfied, and one patient was unsatisfied. The mean of Vancouver scar scale was 1.4 (range of 0–3). Improvement in range of flexion and extension of the wrist was significant without a significant complication.

Conclusion Arthroscopic excision of dorsal wrist ganglion in the way described in this study is a safe and effective method that improves pain and range of motion of the wrist without major complications. The rate of recurrence was less than those reported for open surgery in long-term follow-up. The surgery scar has a promising score in Vancouver scar scale.
Is There a Relationship between Optic Nerve and Chiasm Measurements with HbA1c Levels in Diabetic Patients?
Authors: Bekin Sarıkaya Pelin Zeynep , Bayar Muluk Nuray , Özdemır Adnan , Güngüneş Aşkın
Published: November 2022

Objectives We investigated the optic nerve (ON) and chiasm (OC) in magnetic resonance (MR) in diabetic patients by comparing them with hemoglobin A1c (HbA1c) levels.

Methods In this retrospective study, cranial MRIs of 42 adults (19 males and 23 females) with diabetes mellitus (DM) (group1) and 40 healthy controls (19 males and 21 females) (group 2) were included. In both groups, bilateral ON widths and OC area, width, and height were measured. In the DM group, HbA1c values were also obtained at the time of MRI or within the same month.

Results In the DM group, the mean of the HbA1c values was 8.31 ± 2.51%. There were no significant differences between ON diameter; and OC area, width and height of the DM and control groups (p > 0.05). In each of the DM and control groups, ON diameter was not different between the right and left sides (p > 0.05). In DM groups, correlation tests showed that there were positive correlations between right and left ON diameters, OC area and OC width, and OC height (p < 0.05). In males, ON diameters were higher than those in females bilaterally (p < 0.05). In patients with higher HbA1c values, OC width was smaller (p < 0.05).

Conclusion A significant correlation of OC width and HbA1c levels suggests that uncontrolled DM causes ON atrophy. Our study represents a thorough assessment of OC measures using standard brain MRI to evaluate optic degeneration in DM patients and shows that the OC width measurement is suitable and reliable. This simple method can be obtained from clinically available scans.
Solitons in low-dimensional magnets: Elementary excitations with a nontrivial dispersion law
Authors: Galkina E. G. , Kireev V. E. , Ivanov B. A.
Published: November 2022

Solitons are known to play the role of elementary excitations for one-dimensional ordered systems, like atomic chains with charge or spin ordering. The main characteristic of solitons is their dispersion relation, dependence of soliton energy on the linear momentum. Topological kink-type solitons are the simplest and most important for the description of many physical properties of one-dimensional magnets. Here we provide a detailed analysis of solitons in some general class of magnets, ferrimagnets with the spin compensation point. The nonlinear spin dynamics of ferrimagnets are examined using a nonlinear sigma-model for the antiferromagnetic vector, which is a generalization of the Landau-Lifshitz equation for ferromagnets and sigma-model for the antiferromagnets. The characteristic features of this equation are governed by the value of the compensation parameter, describing the rate of compensation of spins of sublattices. The dispersion relation for kink-type solitons appears to be quite nontrivial, including periodic dispersion law for continuum model of magnet or the presence of ending point for kink spectrum.
Nematic superconductivity in a one-dimensional system of massless fermions
Authors: Loktev V. M. , Turkowski V.
Published: November 2022

The superconducting properties of the one-dimensional model of “relativistic” fermions with attraction generated by antiferromagnetic (Heisenberg) pair superexchange spin interaction are studied. Namely, we demonstrate that such a pairing in this system takes place in the nematic channel, with extended s-wave symmetry, where the attraction between fermions mostly takes place when the fermions occupy the nearest sites. It is demonstrated, that the zero-temperature properties of such a system are rather different from the “standard” case of superconductivity with local attraction. For instance, the order parameter has an unusual helical momentum dependence, ∼e−ika, where a is the lattice parameter and the dependence of the gap on doping has a bell shape, qualitatively similar to cuprate high-Tc superconductors. Finally, the smooth transition from the overlapping pair to the local pair regime (or BCS–BEC crossover) in the nematic phase takes place at much lower values of doping as compared to the local pairing case, i.e., the “relativistic 1D” nematic superconductor is much less “friendly” to the local pairs. We also discuss the possible relation of the properties of this model to the superconducting properties of twisted graphene.
Davydov–Kyslukha model as the starting point in the development of integrable multi-component nonlinear dynamical systems on quasi-one-dimensional lattices
Authors: Vakhnenko Oleksiy O.
Published: November 2022

The Davydov–Kyslukha nonlinear exciton-phonon model on a regular one-dimensional lattice is asserted to be the driving force for the development of integrable multi-component nonlinear dynamical systems encompassing excitonic, vibrational and orientational degrees of freedom. The two most representative quasi-one-dimensional integrable multi-component nonlinear systems inspired by the Davydov–Kyslukha model are presented explicitly in their concise Hamiltonian forms. The new six-subsystem integrable nonlinear model on a regular quasi-one-dimensional lattice is proposed and its derivation based upon the appropriate zero-curvature representation is presented. The constructive aspect of the famous Davydov motto is illustrated by the examples of semi-discrete integrable nonlinear dynamical systems canonicalizeable via the proper point transformations to the physically motivated field variables.
Methods and instruments for the measurement of numerical aperture for microscope objective lens: A mini review
Authors: Zhang Cuiling
Published: November 2022

Numerical aperture (NA) of objective lens is an important parameter for the design of microscope systems and evaluation of imaging characteristics. The present mini review presents and summarizes the methods and instruments used in the NA measurement of objective lens. Five different categories of methods are introduced, which are original versions of apertometer measurement for angular aperture, method based on the working of Abbe apertometer and its modified versions, geometry-based methods, focal-plane (FP)-imaging-based methods, and back-FP-imaging-based methods, respectively. The methodology, devices, applied scenarios, and characteristics of methods (instruments) are summarized. Finally, some issues and potential areas of application are indicated as well.
Survey of Hyperfine Structure Measurements in Alkali Atoms
Authors: Allegrini Maria , Arimondo Ennio , Orozco Luis A.
Published: November 2022

The spectroscopic hyperfine constants for all the alkali atoms are reported. For atoms from lithium to cesium, only the long lived atomic isotopes are examined. For francium, the measured data for nuclear ground states of all available isotopes are listed. All results obtained since the beginning of laser investigations are presented, while for previous works the data of Arimondo et al. [Rev. Mod. Phys. 49, 31 (1977)] are recalled. Global analyses based on the scaling laws and the hyperfine anomalies are performed.
A compact mesoband microwave radiation system
Authors: Wu Zhaoyang , Xu Gang , Lu Wei , Ding Enyan , Zhang Jinqi
Published: November 2022

A compact mesoband radiation system is designed and tested. The system is composed of a charging power supply, a Marx generator, a switched quarter-wavelength oscillator, and a circularly polarized patch antenna. The Marx generator outputs a fast high-voltage pulse with a rise time of 10 ns and an amplitude of 100 kV, which is used to charge the oscillator. The oscillator consists of a quarter-wavelength coaxial transmission line, a ring ground switch, and a coupler. It generates a mesoband oscillation pulse with a center frequency of 350 MHz and a percentage bandwidth of 10%. The oscillation pulse is radiated by the circularly polarized patch antenna. The measured radiation factor is greater than 50 kV, and the radiation waveform is consistent with the simulation waveform.
A comparative study of finite element schemes for micromagnetic mechanically coupled simulations
Authors: Reichel Maximilian , Xu Bai-Xiang , Schröder Jörg
Published: November 2022

Magnetic materials find wide applications in modern technology. For further materials design and optimization, physics-grounded micromagnetic simulations play a critical role, as predictions of properties, regarding the materials to be examined, can be made on the basis of in silico characterizations. However, micromagnetism, in particular, the Landau–Lifshitz–Gilbert equation, poses an interesting but challenging numerical issue, particularly the constraint of the preserved magnetization magnitude far below Curie temperature. Since this requirement is not fulfilled a priori, additional measures must be considered. In this work, four different methods for conserving the length of the magnetization vector in the framework of the finite element method are compared, namely, a projection method, penalty method, a Lagrange multiplier, and the approximation of the magnetization vectors using arithmetical and circular spherical coordinates. By applying the described methods to appropriate numerical examples, the different advantages and disadvantages are worked out so that a clear recommendation for the perturbed Lagrange method can be derived.
Identifying partial topology of simplicial complexes
Authors: Fan Ziye , Wu Xiaoqun
Published: November 2022

This paper investigates partial topology identification of simplicial complexes based on adaptive synchronization. For the nodes of interest, the interactions that they participate in can be accurately reconstructed by designing adaptive controllers and parameter estimators. Particularly, not only pairwise interactions but a higher-order structure can be effectively recovered by our method. Moreover, a new linear independence condition with a rigorous definition is established for parameter estimators to converge asymptotically to the true values. Numerical simulations on a general two-dimensional simplicial complex as well as a real-world structure are provided to show the validity of the result and discuss the influence of different parameters on the identification process.
RF-driven atmospheric-pressure capillary plasma jet in a He/O2 gas mixture: Multi-diagnostic approach to energy transport
Authors: Winzer T. , Steuer D. , Schüttler S. , Blosczyk N. , Benedikt J. , Golda J.
Published: November 2022

Atmospheric-pressure plasma jets operated in noble gases with an oxygen admixture have high application potential in industry and medicine. In this paper, we report on an extension of the well-studied RF-driven plasma jet from the European Cooperation in Science and Technology (COST-Jet), which has shown to deliver stable and reproducible discharge conditions but is limited to the α-discharge mode at low input powers. The so-called capillary-jet features the same discharge geometry as the COST-Jet, but the plasma is ignited inside a capillary with a square cross section acting as a dielectric in front of the electrodes. This prevents a glow-to-arc-transition at high input powers and allows stable operation in the γ-mode. We performed a set of measurements on the capillary-jet in the α- and γ-mode and compared the α-mode results to data obtained for the COST-Jet showing that the discharges are indeed similar and that the capillary-jet extends the accessible parameter range to high input powers. The presented results include power characteristics, temperature measurements, atomic oxygen densities from helium state enhanced actinometry, and molecular beam mass spectrometry (MBMS) as well as ozone densities from MBMS as functions of input power and molecular oxygen admixture. The results are summarized into an energy balance with most of the power dissipated into heating of the plasma feed gas.
The introduction of carbon nanosheet buffer layer for enhanced hydrogen evolution performance of C3N4/CoP photocatalysts
Authors: Zheng Xiaochun , Ren Shoutian , Gai Qixiao , Wang Yidi , Liu Wenjun
Published: November 2022

Various defects of nanocomposites inevitably bring some harmful effects on their photoelectric performance, especially considering that interface defects seriously hinder the carrier interfacial transfer. Here, the interface optimization can be realized between graphitic carbon nitride (C3N4) and CoP co-catalyst by the introduction of good conductive carbon nanosheets (CNs). As a result, the defect density of synthesized C3N4/CNs/CoP is reduced to 1.40 × 1012 cm−3 from 2.55 × 1012 cm−3 of C3N4/CoP, and its interface impedance is correspondingly reduced to 34% of that of C3N4/CoP. Therefore, the optimal H2 evolution rate of 5.26 mmol g−1 h−1 and apparent quantum efficiency of 9.27% at 420 nm are realized, which are 4.8 and 8.1 times that of C3N4/CoP photocatalyst in the absence of CNs, respectively. This work provides a general solution to reduce defect density and carrier transfer resistance in nanocomposites by the introduction of a highly conductive buffer layer.
Physical processes leading to surface erosion and dust particles dynamics of airless bodies
Authors: Zakharov A. V. , Popel S. I. , Kuznetsov I. A. , Borisov N. D. , Rosenfeld E. V. , Skorov Yu. , Zelenyi L. M.
Published: November 2022

The article is a review of the state of research on physical processes occurring near the surface of airless bodies, in particular, the Moon, asteroids, comets, which lead to their erosion, that is, to the modification of superficial and sometimes even deeper layers. External influences on the bodies are considered—micrometeor streams, solar wind and geomagnetic tail plasma flows, solar electromagnetic radiation, and cosmic rays, which are the main causes of erosion. The main features of airless bodies belonging to different classes are given. The main physical mechanisms that can lead to the release and removal of dust particles from the surface of regolith are analyzed, in particular, the energy aspects of high-speed micrometeor impacts, electrostatic processes of particle release from the surface, and thermodynamic processes occurring in the near-surface layers of cometary nuclei. The conditions for the removal of dust particles from the surface of a rotating body and the conditions under which the body can collapse are considered. Depending on the characteristics of these bodies, the processes of erosion, as well as the causes of its occurrence, can vary significantly. The main unresolved problems associated with the processes of erosion of bodies, which require further research, are considered.
Pfaffian, breather, and hybrid solutions for a (2 + 1)-dimensional generalized nonlinear system in fluid mechanics and plasma physics
Authors: Cheng Chong-Dong , Tian Bo , Ma Yong-Xin , Zhou Tian-Yu , Shen Yuan
Published: November 2022

Fluid mechanics is seen as the study on the underlying mechanisms of liquids, gases and plasmas, and the forces on them. In this paper, we investigate a (2 + 1)-dimensional generalized nonlinear system in fluid mechanics and plasma physics. By virtue of the Pfaffian technique, the Nth-order Pfaffian solutions are derived and proved, where N is a positive integer. Based on the Nth-order Pfaffian solutions, the first- and second-order breather solutions are obtained. In addition, Y-type and X-type breather solutions are constructed. Furthermore, we investigate the influence of the coefficients in the system on those breathers as follows: The locations and periods of those breathers are related to δ1, δ2, δ3, δ4, and δ5, where δc's (c=1,2,3,4,5) are the constant coefficients in the system. Moreover, hybrid solutions composed of the breathers and solitons are derived. Interactions between the Y/X-type breather and Y-type soliton are illustrated graphically, respectively. Then, we show the influence of the coefficients in the system on the interactions between the Y/X-type breather and Y-type soliton.
Stable and broadband photodetectors based on 3D/2D perovskite heterostructures with surface passivation
Authors: Zha Yanfang , Wang Yun , Sheng Yuhang , Zhang Xiaowei , Shen Xinyue , Xing Fangjian , Liu Cihui , Di Yunsong , Cheng Yingchun , Gan Zhixing
Published: November 2022

Despite increasing research interest in two-dimensional (2D) perovskites, the stability and spectral response range of the photodetectors based on 2D perovskites are yet far from satisfactory. In this work, a semiconductor heterojunction is constructed based on dimethyl itaconate (DI) treated (BA)2PbI4 microplates and CsPb(Brx/I1−x)3 nanocrystals. The DI treatment not only passivates the defects but also blocks the moisture, resulting in improved stability and suppressed defect trapping. Meanwhile, the type-II heterojunctions facilitate the separation of electron–hole pairs. As a result, the photodetector based on the DI-(BA)2PbI4/CsPb(Brx/I1−x)3 exhibits a responsivity up to 209 nA/mW and a detectivity up to 5.9 × 108 Jones with a broad spectral response range of 400–600 nm. Furthermore, after storage in the ambient environment for 10 days, the responsivity retains about 70%, which is significantly ameliorated compared to the photodetector based on bare (BA)2PbI4 (drops more than 90%). Therefore, this work demonstrates that surface passivation and 2D/three-dimensional heterojunctions are promising strategies to improve responsivity, broaden spectral response range, and enhance stability of photodetectors based on 2D perovskites.
Existence of multi-bump solutions for a nonlinear Kirchhoff-type system
Authors: Liu Weiming
Published: November 2022

In this paper, we use the Lyapunov–Schmidt reduction method to obtain the existence of multi-bump solutions for a nonlinear Kirchhoff-type system with the parameter ɛ. As a result, when ɛ → 0, the system has more and more multi-bump positive solutions.
Heat flux enhancement by regular surface protrusion in partitioned thermal convection
Authors: Kar Prabir Kumar , Chetan Ujjwal , Mahato Jagannath , Sahu Toshan Lal , Das P. K. , Lakkaraju Rajaram
Published: November 2022

We investigate the influence of the regular roughness of heated and cooled plates and adiabatic partition boards on the mean heat transport in a square Rayleigh–Bénard (RB) convection enclosure by two-dimensional direct numerical simulations. The roughness is in the form of isothermal protrusions with a rectangular base and triangular tip. The protrusion height varies from 10% to 25% of enclosure height. With increased protrusion height, the large-scale circulation cannot wash out the cavity between two consecutive protrusions. Thus, the overall heat transport of the enclosure impedes. We have inserted the partition boards between two successive protrusions with a gap between the conduction plate and the partition board to wash out the cavity. The partition board height varies from 20% to 99.8% of enclosure height. We have performed the simulations for the range of Rayleigh number 106–108 and at a fixed Prandtl number of 1. The tip of the triangular protrusion acts as an active plume-emitting spot. We observe a single large-scale elliptical roll with counter-rotating corner rolls for small partition board height. With an increase in partition board height, an elliptical large-scale roll breaks down into the number of large-scale rolls horizontally placed one beside the other. Finally, we observe multiple rolls stacked vertically when the partition boards almost touch the conduction walls. Heat flux enhancement strongly depends on large-scale flow structures. We found a maximum heat flux enhancement in protrusion with partitioned RB case approximately up to 4.7 times the classical square RB for an optimal gap between conduction plate and partition board. The maximum heat transport enhancement is due to the strong horizontal flow through the gap between the conduction plate and partition board, which locally reduces the thermal boundary layer's thickness. The interaction between the horizontal jets and the thermal boundary layers enhances heat transport.
Explosive dispersal of particles in high speed environments
Authors: Durant B. A. , Garno J. , Ouellet F. , Jackson T. L. , Balachandar S. , Littrell D.
Published: November 2022

In this paper, we present the results of the explosive dispersal of particles in high-speed environments. We carry out Euler–Lagrange numerical simulations of a source at quiescent ambient conditions as well as moving at Mach numbers of 3 and 6. Particle volume fractions of 0%, 1%, and 4.5% are presented. The detonation profile is computed with the Jones–Wilkins–Lee equation of state using a reactive burn model. Non-static cases provide a framework to consider the effect of a bow shock and pre-existing high-speed flow conditions on the dispersal process. We also compute averages of both static and dynamic pressures, as well as impulse density histories on virtual probe planes to characterize the momentum of the flow and particles that would deposit on a target. Results suggest that the presence of the particles can have a substantial effect on the pressure average of the virtual target planes.
Nitrobenzene detection using pristine and transition metal-decorated C[18] cyclocarbon: A first-principles density functional theory study
Authors: Lakshmy Seetha , Joseph Saju , Sanyal Gopal , Kalarikkal Nandakumar , Chakraborty Brahmananda
Published: November 2022

Carbon-based nanomaterials have been extensively used for gas or biomolecule sensing applications in recent years. Nitrobenzene (NB) is one of the major environmental pollutants, and its excessive discharge into the atmosphere is a serious menace to all living beings. Hence, effective sensing of the NB is required. In the present work, we have studied the NB adsorption properties of the recently discovered allotrope of carbon, cyclocarbon (C[18]), and transition metal (TM = Sc, Ti, and Cr)-decorated C[18] using the density functional theory method. The NB molecule is physisorbed on the pristine C[18] with a low adsorption energy of −0.49 eV. Among the three TMs, the Sc and Ti atoms strongly bind on the cyclocarbon with a binding energy of −2.47 and −1.87 eV, respectively, resulting in an improvement in the conductivity of the pristine C[18]. NB adsorption on the Sc-decorated system is found more favorable, with a considerably larger adsorption energy of −2.993 eV than the pristine C[18]. The improved adsorption is due to the orbital interaction and the charge transfer of 0.562e from the Sc 3d orbitals to the O 2p orbitals of the NO2 group in NB. This work could provide a theoretical foundation for developing a potentially novel NB sensor based on the TM-decorated C[18] cyclocarbon.
The groove at blade tip designed for suppression of tip-leakage vortex may bring the risk of inducing new cavitation
Authors: Jiang Jing-Wei , Xie Chun-Mei , Xu Liang-Hao , Li Liang , Huang Wei-Xi
Published: November 2022

Previous research showed that slotting at the tip section of a rotating machinery blade could suppress the tip-leakage vortex (TLV) by forming a new groove flow, while the possible adverse effects caused by the discontinuous tip section have not fully been studied. In this Letter, unfavorable effects due to an extra cavitation caused by the groove found in the standard incipient cavitation experiments are reported. Then, this anomaly is clarified by using large eddy simulation that the grooves cause step-like flows and induce low-pressure areas behind the groove near the pressure surface. This increased risk of inducing new cavitation deserves special attention when the medium is water.
English translation of Giesekus's famous article on the elasticity of liquids
Authors: Germann Natalie , Wagner Norman J. , Beris Antony N.
Published: November 2022

Starting from a suspension of elastic dumbbells or chain-like particle aggregates as a simple model of a viscoelastic liquid, the rheological equation of state is inductively derived into which the concept of an “elastic strain component” (recoverable strain) is incorporated and can be understood as a nonlinear extension of the so-called “generalized Maxwell model.” Here, the liquid is characterized by a sequence of nested continua, each associated with an elasticity law. The consideration of the directional dependence of the mobility of the structural elements requires that the behavior of the liquids represented in this way generally deviates from a Weissenberg liquid.
Spinor solutions of a Chern–Simons model for the superconformal algebra
Authors: Alvarez Pedro D , Ortiz Juan
Published: November 2022

We present analytical solutions for homogenous and isotropic spaces of the supersymmetric Chern–Simons model with matter in the adjoint representation. The configurations that we found correspond to a gravitating spinor content and torsion is also present. The spinor behaves like dark energy in the sense that drives an exponential expansion. The solution found can be seen as an anisotropic fluid.
A spintronic analog of the Landauer residual resistivity dipole on the surface of a topological insulator containing a line defect
*
Authors: Fabiha Raisa , Bandyopadhyay Supriyo
Published: November 2022

The Landauer ‘residual resistivity dipole’ is a well-known concept in electron transport through a disordered medium. It is formed when a defect/scatterer reflects an impinging electron causing negative charges to build up on one side of the scatterer and positive charges on the other. This charge imbalance results in the formation of a microscopic electric dipole that affects the electrical resistivity of the medium. Here, we show that an equivalent entity forms in spin polarized electron transport on the surface of a real topological insulator (TI) such as Bi2Te3 containing a line defect. When electrons reflect from such a scatterer, a local spin imbalance forms owing to spin accumulation on one side and depletion on the other side of the scatterer, resulting in a spin current that flows either in the same or in the opposite direction as the injected spin current, and hence, either decreases or increases the spin resistivity. Spatially varying local magnetic fields appear in the vicinity of the scatter, which will cause transiting spins to precess and emit electromagnetic waves. If the current injected into the TI is an alternating current, then the magnetic field’s polarity will oscillate in time with the frequency of the current and if the spins can follow quasi-statically, then they will radiate electromagnetic waves of the same frequency, thereby making the scatterer act as a miniature antenna.
Structure-preserved meta-learning uniting network for improving low-dose CT quality
Authors: Zhu Manman , Mao Zerui , Li Danyang , Wang Yongbo , Zeng Dong , Bian Zhaoying , Ma Jianhua
Published: November 2022

Objective. Deep neural network (DNN) based methods have shown promising performances for low-dose computed tomography (LDCT) imaging. However, most of the DNN-based methods are trained on simulated labeled datasets, and the low-dose simulation algorithms are usually designed based on simple statistical models which deviate from the real clinical scenarios, which could lead to issues of overfitting, instability and poor robustness. To address these issues, in this work, we present a structure-preserved meta-learning uniting network (shorten as ‘SMU-Net’) to suppress noise-induced artifacts and preserve structure details in the unlabeled LDCT imaging task in real scenarios. Approach. Specifically, the presented SMU-Net contains two networks, i.e., teacher network and student network. The teacher network is trained on simulated labeled dataset and then helps the student network train with the unlabeled LDCT images via the meta-learning strategy. The student network is trained on real LDCT dataset with the pseudo-labels generated by the teacher network. Moreover, the student network adopts the Co-teaching strategy to improve the robustness of the presented SMU-Net. Main results. We validate the proposed SMU-Net method on three public datasets and one real low-dose dataset. The visual image results indicate that the proposed SMU-Net has superior performance on reducing noise-induced artifacts and preserving structure details. And the quantitative results exhibit that the presented SMU-Net method generally obtains the highest signal-to-noise ratio (PSNR), the highest structural similarity index measurement (SSIM), and the lowest root-mean-square error (RMSE) values or the lowest natural image quality evaluator (NIQE) scores. Significance. We propose a meta learning strategy to obtain high-quality CT images in the LDCT imaging task, which is designed to take advantage of unlabeled CT images to promote the reconstruction performance in the LDCT environments.
Morphing wing design using integrated and distributed trailing edge morphing
Authors: Mkhoyan Tigran , Thakrar Nisarg R , De Breuker Roeland , Sodja Jurij
Published: November 2022

The presented study investigates the design and development of an autonomous morphing wing concept developed in the scope of the SmartX project, which aims to demonstrate in-flight performance optimisation with active morphing. To progress this goal, a novel distributed morphing concept with six translation induced camber morphing trailing edge modules is proposed in this study. The modules are interconnected using elastomeric skin segments to allow seamless variation of local lift distribution along the wingspan. A fluid-structure interaction optimisation tool is developed to produce an optimised laminate design considering the ply orientation, laminate thickness, laminate properties and actuation loads of the module. Analysis of the kinematic model of the integrated actuator system is performed, and a design is achieved, which meets the required continuous load and fulfils both static and dynamic requirements in terms of bandwidth and peak actuator torque with conventional actuators. The morphing design is validated using digital image correlation measurements of the morphing modules. Characterisation of mechanical losses in the actuator mechanism is performed. Out-of-plane deformations in the bottom skin and added stiffness of the elastomer are identified as the impacting factors of the reduced tip deflection.
Numerical and experimental study of a novel GER fluid damper based on helical duct flow
Authors: Zhao Jinglei , Cao Xijun , Jing Yan , Chen Xu , Bai Ruqing , Yi Jin , Luo Jun , Pu Huayan
Published: November 2022

The benefits of giant electrorheological fluids (GER fluids) have been harnessed to enhance their effect in damping force generation. However, few results have been reported on the issue of taking advantage of a helical duct flow in improving the performance of a GER-based damper in generating and tuning damping effects. In this study, an innovative GER fluid-based damper with helical flow ducts is proposed. The proposed flow mode can achieve a greater pressure gradient during operation, and, thus, improve the damping performance by enlargement of the length of the active region with more compact dimensions. A mathematical model aiming to explain the mechanical properties of the damper is investigated based on the continuity equation and Navier–Stokes equations. Then, simulation studies based on computational fluid dynamics (CFD) solvers are conducted to verify the effectiveness of the mathematical model. Additionally, an experimental prototype of the GER fluid damper is fabricated, and damping force measurements under different excitations are carried out. The experimental results agree well with the results obtained from theoretical analysis and CFD solvers. The regulation coefficient that illustrates the tunable range of the damping force is found to reach a value of eight times under an electric field ranging from 0 to 1 kV mm−1.
Designing disordered multi-functional metamaterials using the discrete dipole approximation
Authors: Capers J R , Boyes S J , Hibbins A P , Horsley S A R
Published: November 2022

The ability to design passive structures that perform different operations on different electromagnetic fields is key to many technologies, from beam-steering to optical computing. While many techniques have been developed to optimise structures to achieve specific functionality through inverse design, designing multi-function materials remains challenging. We present a semi-analytic method, based on the discrete dipole approximation, to design multi-functional metamaterials. To demonstrate the generality of our method, we present two key examples. Firstly, we work at optical wavelengths to design a disordered 2D arrangement of silicon spheres that beams light into different directions depending on the source polarisation. Secondly, we design a 3D device that works at microwave wavelengths and sorts plane waves by their angle of incidence. In this case, the scatterers are more complicated meta-atoms, with a strong dipole resonance at microwave frequencies.
Self-consistent description of Bose–Bose droplets: modified gapless Hartree–Fock–Bogoliubov method
Authors: Zin Paweł , Pylak Maciej , Idziaszek Zbigniew , Gajda Mariusz
Published: November 2022

We define a formalism of a self-consistent description of the ground state of a weakly interacting Bose system, accounting for higher order terms in expansion of energy in the diluteness parameter. The approach is designed to be applied to a Bose–Bose mixture in a regime of weak collapse where quantum fluctuations lead to stabilization of the system and formation of quantum liquid droplets. The approach is based on the generalized Gross–Pitaevskii equation accounting for quantum depletion and renormalized anomalous density terms. The equation is self-consistently coupled to modified Bogoliubov equations. We derive well defined procedure to calculate the zero temperature renormalized anomalous density—the quantity needed to correctly describe the formation of quantum liquid droplet. We pay particular attention to the case of droplets harmonically confined in some directions. The method allows to determine the Lee–Huang–Yang-type contribution to the chemical potential of inhomogeneous droplets when the local density approximation fails.
Bayesian WIMP detection with the Cherenkov Telescope Array
Authors: Mangipudi Abhi , Thrane Eric , Balazs Csaba
Published: November 2022

Over the past decades Bayesian methods have become increasingly popular in astronomy and physics as stochastic samplers have enabled efficient investigation of high-dimensional likelihood surfaces.
In this work we develop a hierarchical Bayesian inference framework to detect the presence of dark matter annihilation events in data from the Cherenkov Telescope Array (CTA). Gamma-ray events are weighted based on their measured sky position Ω̂
m
and energy Em
in order to derive a posterior distribution for the dark matter's velocity averaged cross section 〈σv〉. The dark matter signal model and the astrophysical background model are cast as prior distributions for (Ω̂
m
, Em
). The shape of these prior distributions can be fixed based on first-principle models; or one may adopt flexible priors to include theoretical uncertainty, for example, in the dark matter annihilation spectrum or the astrophysical distribution of sky location. We demonstrate the utility of this formalism using simulated data with a Galactic Centre signal from scalar singlet dark-matter model. The sensitivity according to our method is comparable to previous estimates of the CTA sensitivity.
Is Jet Re-orientation the Elusive Trigger for Star Formation Suppression in Radio Galaxies?
Authors: Garofalo David , Moravec Emily , Macconi Duccio , Singh Chandra B.
Published: November 2022

Jet re-orientation associated with the time evolution of radio quasars explains the formation of X-shaped radio galaxies and their preference for isolated environments. But since X-shaped radio galaxies are generally not found in dense environments (e.g., groups/clusters), the jet re-orientation phenomenon for radio galaxies in groups and clusters has been ignored. We take a closer look at the re-orientation of FRI jets with respect to FRII jets, and find that it may constitute the as-yet unidentified trigger for star formation suppression in radio galaxies. We show how the recently explored radio “red geyser” galaxies can be interpreted in this context and ultimately reveal a deeper understanding of why FRII radio galaxies are on one side of the star formation enhancement/suppression divide compared to FRI radio galaxies.
Dynamics of magnetic microbubble transport in blood vessels
Authors: Chen Jie , Wang Chenghui , Mo Runyang
Published: November 2022

Magnetic microbubbles (MMBs) can be controlled and directed to the target site by a suitable external magnetic field, and thus have potential in therapeutic drug-delivery application. However, few studies focus on their dynamics in blood vessels under the action of magnetic and ultrasonic fields, giving little insight into the mechanism generated in diagnostic and therapeutic applications. In this study, equations of MMBs were established for simulating translation, radial pulsation and the coupled effect of both. Meanwhile, the acoustic streaming and shear stress on the vessel wall were also presented, which are associated with drug release. The results suggest that the magnetic pressure increases the bubble pulsation amplitude, and the translation coupled with pulsation is manipulated by the magnetic force, causing retention in the target area. As the bubbles approach the vessel wall, the acoustic streaming and shear stress increase with magnetic field enhancement. The responses of bubbles to a uniform and a gradient magnetic field were explored in this work. The mathematical models derived in this work could provide theoretical support for experimental phenomena in the literature and also agree with the reported models.
Precise measurement of 171Yb magnetic constants for 1
S
0–3
P
0 clock transition
Authors: Zhang Ang , Tian Congcong , Zhu Qiang , Wang Bing , Xiong Dezhi , Xiong Zhuanxian , He Lingxiang , Lyu Baolong
Published: November 2022

We present a precise measurement of 171Yb magnetic constants for 1
S
0–3
P
0 clock transition. The background magnetic field is firstly compensated to < 1 mGs (1 Gs = 10−4 T) through measuring the splitting of two π transitins of 171Yb clock transition at different compensation coils currents. Then, the splitting ratios of the π and σ components of 171Yb clock transition at different bias magnetic fields are measured, and the first-order Zeeman coefficient is determined to be α = 199.49(5) Hz/Gs. The second-order Zeeman shifts at various bias magnetic fields are also measured through interleaved self-comparison in which the bias magnetic fields are modulated between high and low values. The second-order Zeeman coefficient is fitted to be β = –6.09(3) Hz/mT2, which is consistent with the result of NIST group.
Beryllium melt instabilities and ejection during unmitigated current quenches in ITER
Authors: Vignitchouk L. , Ratynskaia S. , Pitts R.A. , Lehnen M.
Published: November 2022

The dynamics of transient liquid beryllium flows induced on the ITER first wall during the current quench stage of unmitigated vertical displacement events are modelled by means of two-dimensional Navier–Stokes simulations. The study focuses on melt that is driven to the first wall panels’ chamfered edges, where free-surface instabilities are the most likely to be seeded. Beyond their impact on plasma-facing component damage, these instabilities potentially result in material ejection in the form of droplets, which may ultimately solidify into dust and accumulate in the vessel. Based on prior integrated numerical predictions of quenching magnetic equilibria, wall energy deposition and melt-related damage in a concrete worst-case disruption scenario, the simulations suggest that, although the liquid layer is significantly destabilized, only 5% of the total melt mass created on the wall surface is lost through ejection. This result can serve as a basis to refine the estimates of the real transient-induced beryllium dust inventory expected in ITER.
Lab-scale measurements of wind farm blockage effects
Authors: Bartl Jan , Aasnæs Camilla H. , Bjørnsen Joakim R. , Stenfelt Gloria , Lande-Sudall David
Published: November 2022

The inflow an individual wind turbine experiences in a farm layout is strongly dependent on flow interaction effects with the turbines surrounding it. In addition to the well-known wake flows, lateral and upstream flow interaction effects, commonly described as wind farm blockage effects, have also recently gained some attention.

In this work, flow measurements in the upstream induction zone of neighboring turbines are presented for different arrangements of three to seven porous actuator discs. It is shown how the upstream induction zones of individual discs merge into a single zone when decreasing the lateral spacing between three discs. As a result, the central disc experiences a higher thrust force than its neighboring discs. For farm arrangements in two rows, an aligned disc setup is observed to result in a larger upstream velocity decrease than offset arrangements.
Probabilistic Wind Park Power Prediction using Bayesian Deep Learning and Generative Adversarial Networks
Authors: Bentsen Lars Ødegaard , Warakagoda Narada Dilp , Stenbro Roy , Engelstad Paal
Published: November 2022

The rapid depletion of fossil-based energy supplies, along with the growing reliance on renewable resources, has placed supreme importance on the predictability of renewables. Research focusing on wind park power modelling has mainly been concerned with point estimators, while most probabilistic studies have been reserved for forecasting. In this paper, a few different approaches to estimate probability distributions for individual turbine powers in a real off-shore wind farm were studied. Two variational Bayesian inference models were used, one employing a multilayered perceptron and another a graph neural network (GNN) architecture. Furthermore, generative adversarial networks (GAN) have recently been proposed as Bayesian models and was here investigated as a novel area of research. The results showed that the two Bayesian models outperformed the GAN model with regards to mean absolute errors (MAE), with the GNN architecture yielding the best results. The GAN on the other hand, seemed potentially better at generating diverse distributions. Standard deviations of the predicted distributions were found to have a positive correlation with MAEs, indicating that the models could correctly provide estimates on the confidence associated with particular predictions.
A one-year comparison of new wind atlases over the North Sea
Authors: Cheynet Etienne , Solbrekke Ida Marie , Diezel Jan Markus , Reuder Joachim
Published: November 2022

The New European Wind Atlas (NEWA) and the Norwegian hindcast archive (NORA3) database have become publicly available since the end of 2019 and mid-2021, respectively. They aim to model the long-term wind climatology with a spatial resolution of ca. 3 km and a temporal resolution of 1 h (NORA3) or 30 min (NEWA). Both products have a high potential for wind energy applications. Although their geographical coverages partly overlap, an inter-comparison of the NEWA and NORA3 databases in an offshore environment is still lacking. The paper compares the hourly mean wind speed and wind direction recorded in 2009 at the FINO1 platform (North Sea) with hindcast data from the NEWA and the NORA3 database. Both products were found to provide reliable estimates of the mean wind speed at 101 m above sea level. However, NORA3 shows slightly better performances than NEWA for the mean wind speed in terms of root-mean-square error, bias, earth mover’s distance (EMD) and Pearson correlation coefficient. For the mean wind direction, a larger circular EMD than previously documented is found, which could be due to a directional bias in the wind vane data. Finally, the Brunt-Väisälä frequency is computed using sea-surface temperature analyses and the air temperature from NORA3 and NEWA at 101 m above sea level. The encouraging description of the static atmospheric stability by the wind atlases opens the possibility to study in more detail thermally-induced wind events for wind resource assessment or wind turbine design.