bluuebunny/crossref_metadata_2025 huggingface dataset:
CsOH-Promoted Regiospecific Sulfenylation, Selenylation, and Telluration of Indoles in H2O
Authors: Wang Xue-Qiang , Li Ningbo , Xu Shitang , Yi Rongnan , Zeng Chunling , Cui Yue , Xu Xinhua
Published: June 2022

Various indole-containing compounds have shown impressive pharmaceutical activities against a variety of diseases. However, the functionalization of indoles usually relies on systems that use organic solvents, which do not meet the criteria for green and sustainable chemical development. To address this issue, regiospecific sulfenylation, selenylation, and telluration of indoles were developed using H2O as solvent. The highly efficient chalcogenylation of indoles was achieved utilizing CsOH as a promoter, thus avoiding the use of expensive transition-metal catalysts. This newly developed protocol is characterized by its outstanding features including simple operation, mild conditions, wide substrate scope, excellent functional group tolerance, and recyclability, leading to the convenient synthesis of 3-chalcogenyl-indoles.
Reliability of a Submaximal Field Test in Wheelchair
Rugby
Authors: Grossmann Fabian , Perret Claudio , Roelands Bart , Meeusen Romain , Flueck Joelle Leonie
Published: June 2022

The aim was to investigate the test-retest reliability of performance and
physiological variables of a submaximal wheelchair rugby field test. Eight
trained wheelchair rugby athletes with a spinal cord injury (age: median 40,
interquartile range 6.9 y; body mass: median 77.7, interquartile range
23.9 kg) performed a submaximal field test two times with a duration of
41 min, split up into four sets of eight min. Each set included eight
laps with one eight-meter sprint (SP8) and one four-meter sprint (SP4). The
absolute and relative reliability and the performance decrease (fatigue) across
the sets were investigated. The examined variables were sprinting time, heart
rate, and RPE. The measured parameters showed moderate (peak heart rate
ICC3,1=0.663, peak rate of perceived exertion ICC3,1=0.718),
good (SP4 ICC3,1=0.874), and excellent (mean heart rate
ICC3,1=0.905, SP8 ICC3,1=0.985) test-retest reliability. Fatigue
was observed for SP8 in test 2 between set 2/3 and set 2/4. For
test 1 a significant decrease of performance for SP4 was found between set
2/3, set 2/4 and between set 3/4. In conclusion the
submaximal field test showed moderate to excellent reliability for all measured
parameters. The observed fatigue seems to be not clinically relevant. The test
can be recommended to assess the effects of training or interventions.
The Dental Management of Pediatric Patient Diagnosed with Myasthenia Gravis: A Case Report
Authors: AlManea Saad M. , AlHadlaq Mashael A. , AlBuqmi Noura M. , AlGomaiz Sultan S.
Published: June 2022

Myasthenia gravis (MG) is a rare autoimmune neurological disorder characterized by muscle weakness and can vary in severity from the mild form that affects the ocular muscles only to the generalized form that affects the other muscle groups. The prevalence of MG is 150 to 200 per million population over the past 50 years, and approximately 10% of these cases are pediatric patients where the disease onset starts before the age of 18 years. The etiology of MG is due to the blockage of neuromuscular transmission by circulating autoantibodies targeting mainly the nicotinic acetylcholine receptor (AChR) and associated proteins in the postsynaptic membrane of skeletal muscles. In MG patients, dental treatment is challenging due to the nature of the condition and its complexity. Moreover, dentists treating MG patients should acquire knowledge about the disease background and the special considerations that need to be taken. In this case report, our aim was to raise awareness about MG among dentists and discuss the dental management of the patients who have this disease and the precautions that should be taken. This case report presents a pediatric MG patient with poor oral hygiene, multiple decayed teeth, dental fluorosis, tongue thrust oral habit that led to anterior open-bite and uncomplicated crown fracture of the upper permanent central incisors. The decision was made to treat the patient under general anesthesia because of the medical condition and the extent of the dental treatment. In the process of preparing the patient for surgery, the patient was cleared from the treating physicians and was admitted under neurology care as per the primary physician. On the day of surgery, the patient received full-mouth dental rehabilitation under general anesthesia, including pulp therapy, crowns, restorations, and extractions. Furthermore, she was seen regularly in recall visits every 3 months.
Ram to scram mode transition in a simulated flight acceleration
Authors: Zhou Ruixu , Meng Fanzhao , Li Tuo , Li Zhongpeng , Lian Huan
Published: June 2022

Thrust abruption due to mode transition could be catastrophic for hypersonic vehicles. To understand the underlying physics, a direct-connected transient Flight Trajectory Simulator 1 (FTS-1) has been developed at the Institute of Mechanics, Chinese Academy of Sciences. This facility uses advanced high-speed measuring techniques, including thrust and static wall pressure measurement, and Schlieren and hydrocarbon radical chemiluminescence (CH* chemiluminescence) imaging. Kerosene-fueled dual-mode combustor experiments are designed in an acceleration trajectory. The basic operation parameters and the flame and flow dynamics of the acceleration induced mode transition are evaluated. Discussions are given on the triggering mechanisms responsible for the ram to scram mode transition in a simulated flight acceleration.
Viscous Rankine vortices
Authors: Tyvand Peder A.
Published: June 2022

A generalized version of the Rankine vortex is taken as initial state in an infinite fluid domain in two dimensions. The inner rigid-body motion of the Rankine vortex is surrounded by an outer irrotational vortex, where the inner flow and outer flow are allowed to have different amplitudes. We study the time evolution in a viscous fluid, where the kinematic viscosity scales the unit of dimensionless time. By an inverse Hankel transform, the Rankine vortex appears as an integrated continuous spectrum of axisymmetric Fourier–Bessel modes with radial wave numbers k. Each of these velocity modes is represented by a Bessel function J1(kr) where r is the radial distance from the vortex center. The amplitude of each individual mode will decay exponentially at a rate of νk2, where ν is the kinematic viscosity. The decaying continuous Fourier–Bessel spectrum is calculated analytically, while the evolution of the flow field is found by numerical evaluation of an inverse Hankel transform. We also consider the presence of a free surface in the gravity field, where pressure distribution in the vertical direction is hydrostatic. The far field remains irrotational during the viscous decay.
Clocked molecular quantum-dot cellular automata circuits tolerate unwanted external electric fields
Authors: Cong Peizhong , Blair Enrique P.
Published: June 2022

Quantum-dot cellular automata (QCA) may provide low-power, general-purpose computing in the post-CMOS era. A molecular implementation of QCA features nanometer-scale devices and may support ∼THz switching speeds at room-temperature. Here, we explore the ability of molecular QCA circuits to tolerate unwanted applied electric fields, which may come from a variety of sources. One likely source of strong unwanted electric fields may be electrodes recently proposed for the write-in of classical bits to molecular QCA input circuits. Previous models have shown that the input circuits are sensitive to the applied field, and a coupled QCA wire can successfully transfer the input bit to downstream circuits despite strong applied fields. However, the ability of other QCA circuits to tolerate an applied field has not yet been demonstrated. Here, we study the robustness of various QCA circuits by calculating their ground state responses in the presence of an applied field. To do this, a circuit is built from several QCA molecules, each described as a two-state system. A circuit Hamiltonian is formed and diagonalized. All pairwise interactions between cells are considered, along with all correlations. An examination of the ground state shows that these QCA circuits may indeed tolerate strong unwanted electric fields. We also show that circuit immunity to the dominant unwanted field component may be obtained by choosing the orientation of constituent molecules. This suggests that relatively large electrodes used for bit write-in to molecular QCA need not disrupt the operation of nearby QCA circuits. The circuits may tolerate significant electric fields from other sources as well.
The effect of temperature on frequency and instability variations in a smooth-bore relativistic magnetron
Authors: Golabgirnik S. Z. , Shokri B.
Published: June 2022

This paper analyzes the extraordinary mode eigenvalue equation to investigate the effects of temperature on frequency and growth rate of instability in a cylindrical smooth-bore relativistic magnetron. This analysis is based on the framework of the macroscopic fluid model as well as Maxwell's equations, which include electromagnetic and relativistic effects comprehensively. We applied linear perturbation theory around the steady state profiles with the local approximation for perturbed density along the radial direction to derive the eigenvalue equation. The derived eigenvalue equation was solved numerically using shooting to a fitting point method. Due to explosive emission, temperature of about 8 eV is reported [Andreev and Hendricks, IEEE Trans. Plasma Sci. 40, 1551 (2012)]. According to the findings of the current study for the first six azimuthal modes, temperature rise can lead to increasing frequency and decreasing instability in a relativistic magnetron. In addition, after a large number of pulses and rising temperature in the system, the effect of temperature should be considered as an effective element in the oscillations of frequency.
Novel first-principles insights into graphene fluorination
Authors: Malakoutikhah Tahereh , Hashemifar S. Javad , Alaei Mojtaba
Published: June 2022

Fluorination of graphene sheets with xenon difluoride leads to the formation of the widest bandgap Gr derivative, namely, fluorographene. Accurate experimental observations distinguish two stages of mechanism in the fluorination procedure: the half-fluorination stage, wherein one side of the Gr sheet is rapidly fluorinated, and the full-fluorination stage, involving much slower fluorination of the opposite side of the sheet [R. J. Kashtiban et al., Nat. Commun. 5, 5902 (2014)]. Here, we perform comprehensive density functional calculations to illustrate accurate microscopic insights into the much slower rate of the full-fluorination stage compared with the half-fluorination one. The calculated minimum energy paths for the half- and full-fluorination processes demonstrate much enhanced fluorine adsorption after the half-fluorination stage, which sounds inconsistent with the experimental picture. This ambiguity is explained in terms of significant chemical activation of the graphene sheet after half-fluorination, which remarkably facilitates the formation of chemical contaminants in the system and, thus, substantially slows down the full-fluorination procedure. After considering the binding energy and durability of the relevant chemical species, including hydrogen, oxygen, and nitrogen molecules and xenon atom, it is argued that oxygen–fluorine ligands are the most likely chemical contaminants opposing the complete fluorination of a graphene sheet. Then, we propose an oxygen desorption mechanism to carefully explain the much enhanced rate of the full-fluorination procedure at elevated temperatures. The potential photocatalytic application of the pristine and defected samples in water splitting and carbon dioxide reduction reactions is also discussed.
Metriplectic foundations of gyrokinetic Vlasov–Maxwell–Landau theory
Authors: Hirvijoki Eero , Burby Joshua W. , Brizard Alain J.
Published: June 2022

This Letter reports on a metriplectic formulation of a collisional, nonlinear full-f electromagnetic gyrokinetic theory compliant with energy conservation and monotonic entropy production. In an axisymmetric background magnetic field, the toroidal angular momentum is also conserved. Notably, a new collisional current, contributing to the gyrokinetic Maxwell–Ampère equation and the gyrokinetic charge conservation law, is discovered.
Over GHz bandwidth SAW filter based on 32° Y-X LN/SiO2/poly-Si/Si heterostructure with multilayer electrode modulation
Authors: Su Rongxuan , Fu Sulei , Lu Zengtian , Shen Junyao , Xu Huiping , Xu Zhibin , Wang Rui , Song Cheng , Zeng Fei , Wang Weibiao , Pan Feng
Published: June 2022

Enhancing the central frequency (fc) and bandwidth (BW) and reducing insertion loss (IL) are essential steps in surface acoustic wave (SAW) filter applications in the 5G era. With this in mind, we construct a 32° Y-X LiNbO3(300 nm)/SiO2(300 nm)/poly-Si(1 μm)/Si heterostructure to avoid both acoustic leakage through the waveguide effect and electrical loss through the introduction of a poly-Si layer. By separately modulating the electrode thicknesses of series and parallel resonators, the spurious modes can be mitigated out of the filter passband, preventing them from negatively impacting the filter characteristics. Moreover, to reduce Ohmic loss, an optimized design for an Al/Cu/Ti multilayer electrode is proposed as a replacement for the Cu/Ti electrode resonators built on Al/Cu/Ti electrodes provide a high resonance frequency of 3.76 GHz, a large electromechanical coupling coefficient of 23%, and a maximum quality factor of 1510 (twice that of the Cu/Ti electrodes). Finally, SAW filters with an fc of 3728 MHz and a 3-dB BW of 1052 MHz are implemented, with IL of 0.92 dB. The achieved specifications demonstrates that one-chip SAW filter is expected to become n77 band filtering solution.
Structural and magnetic asymmetry at the interfaces of MgO/FeCoB/MgO trilayer: Precise study under x-ray standing wave conditions
Authors: Jamal Md. Shahid , Gupta Pooja , Raj Rakhul , Gupta Mukul , Reddy V. R. , Kumar Dileep
Published: June 2022

Magnetic tunnel junctions based on FeCoB as a magnetic electrode and MgO as a tunneling barrier gained much attention because of their applications in random access memories and magnetic sensors in disk drives. In this work, the structural and magnetic properties of the MgO/FeCoB/MgO trilayer have been studied precisely under x-ray standing wave (XSW) conditions, where XSW is generated through a high-density (Pt) waveguide structure. The combined x-ray scattering and fluorescence data obtained under XSW conditions revealed the formation of a high-density FeCoB layer at the MgO/FeCoB interface (FeCoB-on-MgO) in the as-deposited trilayer. Diffusion of B from the FeCoB layer into MgO is attributed to the formation of Fe- and Co-rich high-density layer (B-deficient FeCoB layer) at the interface. Angular-dependent magnetism of the trilayer structure revealed the presence of in-plane magnetic anisotropy (IMA), which disappeared with thermal annealing at a temperature of 450 °C. Stress in B-deficient FeCoB layer at the interface is attributed to the origin of IMA through magneto-elastic anisotropy energy minimization. The disappearance of anisotropy after annealing is mainly due to the removal of long-range stress and the formation of crystalline bcc-FeCo phase.
Enhanced energy storage properties in relaxor Pb(Mg1/3Nb2/3)O3-PbTiO3 thin-film capacitors by incorporating buffer layers
Authors: Li Yuke , Xu Jibo , Xu Zhiyu , Yu Yahui , Zhang Yuanhao , Lu Lingzhi , Zheng Weijie , Ding Chunyan , Wen Zonghan , Shi Hongyan , Lu Chaojing , Wen Zheng
Published: June 2022

Recently, relaxor ferroelectric thin-film capacitors have attracted considerable attention for energy storage applications since their slim-type polarization–electric field hysteresis loops can yield large recoverable energy density (Wrec) and high efficiency (η). In this work, we study the effects of buffer layers on energy storage properties of 0.93Pb(Mg1/3Nb2/3)O3-0.07PbTiO3 (PMN-PT) thin-film capacitors with a 5 nm-thick SrTiO3 (STO) and LaAlO3 (LAO) films. The energy storage properties of Pt/PMN-PT/SrRuO3 (SRO) capacitors are found to be significantly changed by incorporating the STO or LAO buffer layer at the top Pt/PMN-PT interface, while inserting the buffer layer at bottom PMN-PT/SRO interface shows negligible effects on the electrical properties. Specifically, with the STO buffering, the breakdown field is dramatically increased in the Pt/STO/PMN-PT/SRO capacitor due to the existence of an internal field in the STO, which prevents the growth of electrical trees from the bottom SRO to the top Pt electrode, and a large Wrec of ∼48.91 J/cm3, more than three times of that of the PMN-PT capacitor, is achieved. However, buffered by the LAO, the Pt/LAO/PMN-PT/SRO capacitor exhibits a reduced relaxor character, which may be ascribed to a pinning effect of nanodomains associated with the charged LAO/PMN-PT interface. As a result, both Wrec and η are significantly lowered, compared to the non-buffered PMN-PT capacitor. These results provide physical insights into the modulation of relaxor and dielectric behaviors by designing the characteristics of buffer layers, demonstrating a way for enhancing energy storage properties in thin-film capacitors.
Toward high all-optical data writing rates in synthetic ferrimagnets
Authors: van Hees Youri L. W. , Koopmans Bert , Lavrijsen Reinoud
Published: June 2022

Although all-optical magnetization switching with fs laser pulses has garnered much technological interest, the ultimate data rates achievable have scarcely been investigated. Recently, it has been shown that after a switching event in a GdCo alloy, a second laser pulse arriving 7 ps later can consistently switch the magnetization. However, it is as of yet unknown whether the same holds in layered ferrimagnetic systems, which hold much promise for applications. In this work, we investigate the minimum time delay required between two subsequent switching events in synthetic ferrimagnetic Co/Gd bilayers using two fs laser pulses. We experimentally demonstrate that the minimum time delay needed for consistent switching can be as low as 10 ps. Moreover, we demonstrate the importance of engineering heat diffusion away from the magnetic material as well as control over the laser pulse energy. This behavior is reproduced using modeling, where we find that the second switch can occur even when the magnetization is not fully recovered. We further confirm that heat diffusion is a critical factor in reducing the time delay for the second switch, while also confirming a critical dependence on laser energy.
A miniature piezoelectric pump with high performance
Authors: Yang Zhigang , Dong Luntao , Wang Meng , Li Xingqi , Liu Xiaopeng , Liu Guojun
Published: June 2022

The high performance and miniaturization of the piezoelectric pump are essential for its application. A single-chamber piezoelectric pump with a circular unimorph piezoelectric actuator and cantilever check valves is proposed in this work, which has good output performance and smaller overall size. The working principle of the piezoelectric pump was described, and the theoretical working characteristics of the cantilever check valve were analyzed in detail. The corresponding experimental prototype was made for the output performance assessment. The experimental results show that the pump has good self-suck ability under well-assembled process conditions, which provides a guarantee for the high flow rate and the output pressure of the piezoelectric pump. The maximum flow rate of 4.5 ml/min is obtained when the pump is driven by an offset sinusoidal voltage of 180Vpp at 50 Hz; the maximum output pressure of the pump reaches 52 kPa under 180Vpp at 150 Hz. In addition, at 70 Hz, 180Vpp, the comprehensive performance of the piezoelectric pump is better, with a flow rate above 3 ml/min and an output pressure over 35 kPa. The proposed piezoelectric pump has the characteristics of simple structure, high performance, small size, and low cost, which can be applied in microelectronic cooling, biomedical, and other fields.
Continuous wave interdigital H-mode cavities for alternating phase focusing heavy ion acceleration
Authors: Basten M. , Aulenbacher K. , Barth W. , Burandt C. , Dziuba F. , Gettmann V. , Kürzeder T. , Lauber S. , List J. , Miski-Oglu M. , Yaramyshev S.
Published: June 2022

In the future, a new superconducting (SC) continuous wave (CW) high intensity heavy ion HElmholtz LInear ACcelerator (HELIAC) should provide ion beams with maximum beam energy above the Coulomb barrier for the Super Heavy Element program at GSI (Gesellschaft für Schwerionenforschung, in Engl.: Association for Heavy Ion Research). The HELIAC consists of a SC main accelerator supplied by a normal conducting injector, which comprises an electron cyclotron resonance ion source, a radio-frequency quadrupole, and two separate interdigital H-mode drift-tube linear accelerator cavities, based on an Alternating Phase Focusing (APF) scheme. Together, both cavities will accelerate ions from 300 to 1400 keV/u with only one external quadrupole triplet for transverse focusing in between. Due to the demanding requirements of the APF concept on the voltage distribution along the beam axis on the one hand and the CW operation on the other hand, the optimization of each cavity concerning RF, mechanical, and thermal properties is crucial for the successful operation of the HELIAC injector.
Structural and dynamic properties of solvated hydroxide and hydronium ions in water from ab initio modeling
Authors: Liu Renxi , Zhang Chunyi , Liang Xinyuan , Liu Jianchuan , Wu Xifan , Chen Mohan
Published: June 2022

Predicting the asymmetric structure and dynamics of solvated hydroxide and hydronium in water from ab initio molecular dynamics (AIMD) has been a challenging task. The difficulty mainly comes from a lack of accurate and efficient exchange–correlation functional in elucidating the amphiphilic nature and the ubiquitous proton transfer behaviors of the two ions. By adopting the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation functional in AIMD simulations, we systematically examine the amphiphilic properties, the solvation structures, the electronic structures, and the dynamic properties of the two water ions. In particular, we compare these results to those predicted by the PBE0-TS functional, which is an accurate yet computationally more expensive exchange–correlation functional. We demonstrate that the general-purpose SCAN functional provides a reliable choice for describing the two water ions. Specifically, in the SCAN picture of water ions, the appearance of the fourth and fifth hydrogen bonds near hydroxide stabilizes the pot-like shape solvation structure and suppresses the structural diffusion, while the hydronium stably donates three hydrogen bonds to its neighbors. We apply a detailed analysis of the proton transfer mechanism of the two ions and find the two ions exhibit substantially different proton transfer patterns. Our AIMD simulations indicate that hydroxide diffuses more slowly than hydronium in water, which is consistent with the experimental results.
Electrical contact properties between Yb and few-layer WS2
Authors: Ju Shihao , Qiu Lipeng , Zhou Jian , Liang Binxi , Wang Wenfeng , Li Taotao , Chen Jian , Wang Xinran , Shi Yi , Li Songlin
Published: June 2022

The charge injection mechanism from contact electrodes into two-dimensional (2D) dichalcogenides is an essential topic for exploiting electronics based on 2D channels, but remains not well understood. Here, low-work function metal ytterbium (Yb) was employed as contacts for tungsten disulfide (WS2) to understand the realistic injection mechanism. The contact properties in WS2 with variable temperature (T) and channel thickness (tch) were synergetically characterized. It is found that the Yb/WS2 interfaces exhibit a strong pinning effect between energy levels and a low contact resistance (RC) value down to 5 kΩ μm. Cryogenic electrical measurements reveal that RC exhibits weakly positive dependence on T until 77 K as well as a weakly negative correlation with tch. In contrast to the non-negligible RC values extracted, an unexpectedly low effective thermal injection barrier of 36 meV is estimated, indicating the presence of significant tunneling injection in the subthreshold regime and the inapplicability of the pure thermionic emission model to estimate the height of the injection barrier.
A self-consistent analytical theory for rotator networks under stochastic forcing: Effects of intrinsic noise and common input
Authors: Ranft Jonas , Lindner Benjamin
Published: June 2022

Despite the incredible complexity of our brains’ neural networks, theoretical descriptions of neural dynamics have led to profound insights into possible network states and dynamics. It remains challenging to develop theories that apply to spiking networks and thus allow one to characterize the dynamic properties of biologically more realistic networks. Here, we build on recent work by van Meegen and Lindner who have shown that “rotator networks,” while considerably simpler than real spiking networks and, therefore, more amenable to mathematical analysis, still allow one to capture dynamical properties of networks of spiking neurons. This framework can be easily extended to the case where individual units receive uncorrelated stochastic input, which can be interpreted as intrinsic noise. However, the assumptions of the theory do not apply anymore when the input received by the single rotators is strongly correlated among units. As we show, in this case, the network fluctuations become significantly non-Gaussian, which calls for reworking of the theory. Using a cumulant expansion, we develop a self-consistent analytical theory that accounts for the observed non-Gaussian statistics. Our theory provides a starting point for further studies of more general network setups and information transmission properties of these networks.
Double-layer acoustic metasurface for the suppression of the Mack second mode in hypersonic boundary-layer flow
Authors: Tian Xudong , Liu Tuo , Wang Tiantian , Zhu Jie , Wen Chihyung
Published: June 2022

An acoustic metasurface consisting of two layers of perforated plates is proposed for suppression of the Mack second mode in hypersonic boundary-layer flow. The upper layer with very tiny holes is permeable to acoustic waves and hardly alters the background hypersonic boundary-layer flow, offering rather low resistive and inductive components of surface acoustic impedance. The bottom layer with large and sparse square holes is attached to a rigid wall surface and forms a periodic array of chambers, each covering multiple holes of the upper layer, which can adjust the impedance phase by working as a capacitive component. Based on a linear stability analysis of hypersonic boundary-layer instability, such an acoustic metasurface satisfying the required surface impedance is designed and numerically investigated. The results show that the metasurface can efficiently suppress the Mack second mode over a relatively wide bandwidth. This work provides an alternative strategy for the design of porous walls for hypersonic boundary-layer stabilization.
Compressibility effect on interaction of shock wave and turbulent boundary layer
Authors: Jiang Zhou , Ji Yongchao , Wang Jianchun
Published: June 2022

The compressibility effect when an oblique shock wave impinges on a turbulent boundary layer was analyzed with a direct numerical simulation using Helmholtz decomposition. The turbulent intensity near the impinging region is significantly enhanced by the interaction of the shock wave and boundary layer. In particular, the interaction behavior can enhance the dilatational components of the Reynolds stress and velocity fluctuations. This also enhances the negative correlation between the dilatational components of streamwise and normal velocity fluctuations. The dilatation fluctuation in the impinging region increases significantly. Moreover, in the impinging region, the dilatational components of the production term and transport term contribute to the production and transport terms of the kinetic energy equation mainly in the vicinity of the interface. This simulation shows that the interaction behavior of an oblique shock wave and turbulent boundary layer can enhance flow compressibility significantly. In the interaction region, the turbulent intensity of the flow field is stronger than those upstream and downstream. This study provides a theoretical basis for the improvement of other simulation methods and turbulence modeling for the interaction of an oblique shock wave and turbulent boundary layer.
Evolution of Rayleigh−Taylor instability at the interface between a granular suspension and a clear fluid
Authors: Guo Junwei , Zhou Qi , Wong Ron Chik-Kwong
Published: June 2022

We report the characteristics of Rayleigh–Taylor instabilities (RTI) occurring at the interface between a suspension of granular particles and a clear fluid. The time evolution of these instabilities is studied numerically using coupled lattice Boltzmann and discrete element methods with a focus on the overall growth rate (σ¯) of the instabilities and their average wave number (k¯). Special attention is paid to the effects of two parameters, the solid fraction (0.10≤ϕ0≤0.40) of the granular suspension and the solid-to-fluid density ratio (1.5≤R≤2.7). Perturbations at the interface are observed to undergo a period of linear growth, the duration of which decreases with ϕ0 and scales with the particle shear time d/w∞, where d is the particle diameter and w∞ is the terminal velocity. For ϕ0>0.10, the transition from linear to nonlinear growth occurs when the characteristic steepness of the perturbations is around 29%. At this transition, the average wave number is approximately 0.67d−1 for ϕ0>0.10 and appears independent of R. For a given ϕ0, the growth rate is found to be inversely proportional to the particle shear time, i.e., σ¯∝(d/w∞)−1; at a given R, σ¯ increases monotonically with ϕ0, largely consistent with a linear stability analysis (LSA) in which the granular suspension is approximated as a continuum. These results reveal the relevance of the timescale d/w∞ to the evolution of interfacial granular RTI, highlight the various effects of ϕ0 and R on these instabilities, and demonstrate modest applicability of the continuum-based LSA for the particle-laden problem.
Similarities and differences of
Authors: Boulata K. , Irakli M. , Tsialtas J. T.
Published: June 2022

Context Vicia sativa subsp. macrocarpa (V. macrocarpa), a large-seeded vetch, is underutilised and has been proposed as a putative source of seed feed along with V. sativa subsp. sativa (V. sativa, common vetch). Aims The study aimed to compare the two subspecies for a range of seed yield and quality traits. Methods Three accessions of each subspecies were grown under field conditions during two growing seasons. Measurements included pod and seed morphology, seed yield per plant, pod shattering and seed toughness, seed nutritional traits, and insect damage. Key results No significant differences were found for seed weight per plant (9.95–14.75 g); however, V. macrocarpa accessions showed lower emergence percentages (7–18%) and higher pod shattering (4.01% vs 0.17%) than V. sativa. The higher number of seeds per pod (8.50 vs 7.49) and larger seeds (70.63 vs 59.67 g) significantly contributed to yield of V. macrocarpa. Over the six accessions, seed weight per plant was significantly correlated with harvest index. The darker seeds of V. macrocarpa had lower seed protein concentration (25.96% vs 27.89%) and higher concentrations of antinutritional phenolic compounds (total phenols, total tannins, condensed tannins, flavonoids). Seeds of V. macrocarpa were enriched in manganese (17.72 vs 12.65 mg/kg) compared with V. sativa, but poorer in potassium (8.44 vs 10.50 g/kg). The high manganese and phenolics concentrations in seeds of V. macrocarpa were associated with lower percentages of bruchid-infected seeds and endoparasitoid (Triaspis thoracicus) damaged seeds, possibly due to toxic effects. Conclusions The two subspecies varied significantly in seed quality traits, but not yield. Implications More extensive comparisons between the two subspecies, with larger numbers of accessions, are needed in order to determine the potential of V. macrocarpa as a source of seed feed.
Spindle reorientation in response to mechanical stress is an emergent property of the spindle positioning mechanisms
Authors: Kelkar Manasi , Bohec Pierre , Smith Matthew B. , Sreenivasan Varun , Lisica Ana , Valon Léo , Ferber Emma , Baum Buzz , Salbreux Guillaume , Charras Guillaume
Published: June 2022

Proper orientation of the mitotic spindle plays a crucial role in embryos, during tissue development, and in adults, where it functions to dissipate mechanical stress to maintain tissue integrity and homeostasis. While mitotic spindles have been shown to reorient in response to external mechanical stresses, the subcellular cues that mediate spindle reorientation remain unclear. Here, we used a combination of optogenetics and computational modeling to investigate how mitotic spindles respond to inhomogeneous tension within the actomyosin cortex. Strikingly, we found that the optogenetic activation of RhoA only influences spindle orientation when it is induced at both poles of the cell. Under these conditions, the sudden local increase in cortical tension induced by RhoA activation reduces pulling forces exerted by cortical regulators on astral microtubules. This leads to a perturbation of the balance of torques exerted on the spindle, which causes it to rotate. Thus, spindle rotation in response to mechanical stress is an emergent phenomenon arising from the interaction between the spindle positioning machinery and the cell cortex.
Mutations in
MINAR2
encoding membrane integral NOTCH2-associated receptor 2 cause deafness in humans and mice
Authors: Bademci Guney , Lachgar-Ruiz María , Deokar Mangesh , Zafeer Mohammad Faraz , Abad Clemer , Yildirim Baylan Muzeyyen , Ingham Neil J. , Chen Jing , Sineni Claire J. , Vadgama Nirmal , Karakikes Ioannis , Guo Shengru , Duman Duygu , Singh Nitu , Harlalka Gaurav , Jain Shirish P. , Chioza Barry A. , Walz Katherina , Steel Karen P. , Nasir Jamal , Tekin Mustafa
Published: June 2022

Discovery of deafness genes and elucidating their functions have substantially contributed to our understanding of hearing physiology and its pathologies. Here we report on DNA variants in
MINAR2
, encoding membrane integral NOTCH2-associated receptor 2, in four families underlying autosomal recessive nonsyndromic deafness. Neurologic evaluation of affected individuals at ages ranging from 4 to 80 y old does not show additional abnormalities.
MINAR2
is a recently annotated gene with limited functional understanding. We detected three
MINAR2
variants, c.144G > A (p.Trp48*), c.412_419delCGGTTTTG (p.Arg138Valfs*10), and c.393G > T, in 13 individuals with congenital- or prelingual-onset severe-to-profound sensorineural hearing loss (HL). The c.393G > T variant is shown to disrupt a splice donor site. We show that
Minar2
is expressed in the mouse inner ear, with the protein localizing mainly in the hair cells, spiral ganglia, the spiral limbus, and the stria vascularis. Mice with loss of function of the Minar2 protein (

Minar2
tm1b/tm1b

) present with rapidly progressive sensorineural HL associated with a reduction in outer hair cell stereocilia in the shortest row and degeneration of hair cells at a later age. We conclude that MINAR2 is essential for hearing in humans and mice and its disruption leads to sensorineural HL. Progressive HL observed in mice and in some affected individuals and as well as relative preservation of hair cells provides an opportunity to interfere with HL using genetic therapies.
‘As democracy grows’
Authors: Inya Onwu
Published: June 2022

This paper investigates the metaphorical framing of the concept of democracy in Nigerian Senate debates
(henceforth, NSD) in a mini-corpus of 214 meta-discursive commentaries on democracy by legislators, with insight from metaphor
scenario theory. Three source concepts – “
erect structure”, “living organism”,
“dividends” and their associate scenarios are analysed. These scenarios are exploited by legislators to
effect specific argumentative and ideological conclusions, such as Nigerian democracy is weak, positive-self-presentation by
legislators amongst others. The paper reveals the conceptual, evaluative and ideological structures that dominate the discourse
about democratization in Nigeria, especially in the Fourth Republic, from the perspective of legislators.
Characterisation of heat-treated cobalt–chromium alloy fabricated by selective laser melting
Authors: Lambrou I. , Kaldellis A. , Stergiou V. , Tsakiridis P. E.
Published: June 2022

The present work focuses on the stress-relief annealing (SRA) modification and porcelain firing (PF) treatment effect in biomedical Cobalt–Chromium (Co–Cr) components for dental applications components produced by the SLM process. The specimens’ phase transformation was examined by X-ray diffraction, optical microscopy, scanning and transmission electron microscopy, combined with energy dispersive X-ray spectroscopy. The corresponding mechanical properties were assessed by compression tests and Vickers hardness measurements. The matrix microstructure consisted mainly of the FCC γ phase with a small amount of the HCP-structured ϵ phase. SRA at 750°C and 950°C, followed by PF at the 930°C treatment, increased the percentage of the ϵ phase and caused the precipitation of fine carbides and intermetallic precipitates, thus improving the final mechanical properties.
Improving ecosystem services in farmlands: beginning of a long-term ecological study with restored flower-rich grasslands
Authors: Báldi András , Pellaton Raoul , Bihaly Áron Domonkos , Szigeti Viktor , Lellei-Kovács Eszter , Máté András , Sárospataki Miklós , Soltész Zoltán , Somay László , Kovács-Hostyánszki Anikó
Published: June 2022

Biodiversity declines in an unprecedented way, mostly due to land use change. Restoration interventions proved to be one of the most effective tools to halt the decline, especially in ecosystems such as agricultural fields. Evidence-based, locally adapted recommendations on grassland restoration, however, are often missing, so we present a novel approach for such interventions that can be implemented anywhere and that are based on scientific rigor. In a recently started long-term field ecological study, we established 0.5 ha wildflower parcels, using a diverse local seed mixture of 32 insect-visited plant species in Central European agricultural landscapes in 2020. Our focus is on the landscape-scale effects of this ecological intensification on ecosystem services such as crop yield, pollination and pest control, and the long-term monitoring of the successional processes. The aim is to showcase an effective restoration protocol that could serve as a model for future farm management, and provide much-needed evidence for policy on landscape ecological restoration of international relevance.
Color image restoration based on saturation-value total variation plus L1 fidelity*
Authors: Wang Wei , Song Qifan
Published: June 2022

Color image restoration is one of the most important tasks in image processing. In this paper, we propose and develop a novel saturation-value total variation (SVTV) plus L1 fidelity (SVTV-L1) model for color image restoration. SVTV is incorporated in the proposed model for regularizing the objective color image, meanwhile, L1 norm is considered for data fitting term in the proposed energy functional. Theoretically, we investigate the properties of the objective functional and the objective model. Note that the proposed energy functional including L1 norm is nonsmooth. We develop a smooth approximation approach to study the existence and properties of the solution of the proposed optimization problem. Numerically, Poisson noise and mixed noise have been tested and studied in the experimental results. We formulate an effective and efficient algorithm to solve the proposed minimization problem based on the framework of alternating direction method of multipliers. Numerical examples are presented to demonstrate that the performance of the proposed SVTV-L1 model is better than that of other testing methods in terms of visual quality, peak signal-to-noise ratio, and structure similarity.
Real-time remaining useful life prediction based on adaptive kernel window width density
Authors: Zhang Jiangmin , Shi Hui , Dong Zengshou
Published: June 2022

Remaining useful life (RUL) prediction plays an important role in improving the availability and productivity of systems. To improve the accuracy of real-time RUL prediction during system operation, we propose a modeling method for real-time RUL prediction based on adaptive kernel window width density. First, a non-parametric kernel density estimation (KDE) real-time RUL prediction model is proposed, and a window width model with adaptive kernel window width density is established by introducing a local density factor in the window width selection. The local density of sample points is calculated by the k-nearest neighbor distance, and the KDE is performed by adaptively selecting the window width value according to the local density of sample points in the region of non-uniform distribution of sample points. As the monitoring data changes in real time, the kernel density estimates of known samples are used to recursively update the kernel density estimates of new samples. Moreover, the logarithmic transformation of random variables and space mapping are used in the establishment of the RUL prediction model. A model of logarithmic kernel diffeomorphism transformation is established to solve the boundary shift problem of kernel estimation in the prediction to improve the prediction accuracy. Finally, the validity of the method is verified through case studies, and the accuracy of the model is judged using evaluation quasi-measures.
A contact-based technique for measurement of membrane tension
Authors: Aminian Behzad , Abadi Iman Rahgozar , Green Sheldon , Rogak Steven
Published: June 2022

Membranes are used widely in engineering applications, including the porous membranes in fuel cells and ventilation systems. In order to understand the mechanical behavior of the membrane, one should know the loads acting on it, including the tension applied to it during the manufacturing process. This study describes a novel contact-based method to measure the pre-tension for applications, such as membrane energy exchangers, where optical access to the membrane is limited. The method involves direct measurement of the membrane location under various pressures, using a novel probe, and inferring the pre-tension by comparing the results with theoretical models. The technique is validated by measuring the tension of membranes pre-tensioned to known values. The RMS deviation between the measured tension and the set pre-tension is 0.55 N m−1, which is approximately 3% of the pre-tension used in a typical membrane energy exchanger.
Model-based three-material decomposition in dual-energy CT using the volume conservation constraint
Authors: Liu Stephen Z , Tivnan Matthew , Osgood Greg M , Siewerdsen Jeffrey H , Stayman J Webster , Zbijewski Wojciech
Published: June 2022

Objective. We develop a model-based optimization algorithm for ‘one-step’ dual-energy (DE) CT decomposition of three materials directly from projection measurements. Approach. Since the three-material problem is inherently undetermined, we incorporate the volume conservation principle (VCP) as a pair of equality and nonnegativity constraints into the objective function of the recently reported model-based material decomposition (MBMD). An optimization algorithm (constrained MBMD, CMBMD) is derived that utilizes voxel-wise separability to partition the volume into a VCP-constrained region solved using interior-point iterations, and an unconstrained region (air surrounding the object, where VCP is violated) solved with conventional two-material MBMD. Constrained MBMD (CMBMD) is validated in simulations and experiments in application to bone composition measurements in the presence of metal hardware using DE cone-beam CT (CBCT). A kV-switching protocol with non-coinciding low- and high-energy (LE and HE) projections was assumed. CMBMD with decomposed base materials of cortical bone, fat, and metal (titanium, Ti) is compared to MBMD with (i) fat-bone and (ii) fat-Ti bases. Main results. Three-material CMBMD exhibits a substantial reduction in metal artifacts relative to the two-material MBMD implementations. The accuracies of cortical bone volume fraction estimates are markedly improved using CMBMD, with ∼5–10× lower normalized root mean squared error in simulations with anthropomorphic knee phantoms (depending on the complexity of the metal component) and ∼2–2.5× lower in an experimental test-bench study. Significance. In conclusion, we demonstrated one-step three-material decomposition of DE CT using volume conservation as an optimization constraint. The proposed method might be applicable to DE applications such as bone marrow edema imaging (fat-bone-water decomposition) or multi-contrast imaging, especially on CT/CBCT systems that do not provide coinciding LE and HE ray paths required for conventional projection-domain DE decomposition.
Development of a synthetic phase contrast imaging diagnostic for turbulence studies at Wendelstein 7-X
Authors: Hansen S K , Porkolab M , Bähner J-P , Huang Z , von Stechow A , Grulke O , Edlund E M , Wilms F , Bañón Navarro A , Jenko F , Sánchez E
Published: June 2022

We present a synthetic phase contrast imaging (PCI) diagnostic for studying turbulence at the Wendelstein 7-X (W7-X) stellarator. We first describe the implemented instrument response model, which captures diffraction effects, detector noise, and the long-wavelength cutoff due to the phase plate of the PCI system. To verify the instrument response model, we show that it is capable of reproducing the PCI signal generated by the sound wave speaker used for calibration at W7-X. Next, we discuss the calculation of synthetic PCI signals based on the global, nonlinear gyrokinetic codes GENE-3D and EUTERPE, including results from some of the first stellarator simulations of this type with kinetic electrons (KEs) in GENE-3D. While the simulations used in this work lack a neoclassical radial electric field, which is crucial for reproducing experimental PCI signals, they do indicate that the dominant rotation direction and velocities of the turbulent fluctuations can be inferred from the wave number-frequency spectra of the PCI signals, as expected. The synthetic PCI wave number spectra are further shown to be similar to those of the line-integrated fluctuating electron density, with distinct differences between adiabatic and KE simulations, explainable by previously published turbulence models. For example, the wave number spectra of all adiabatic electron simulations analyzed here follow a power law with an exponent close to −5 for sufficiently large wave numbers. This indicates that universal features of electron density turbulence at W7-X may be studied using the PCI system.