bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of tandem fluttering membranes on flow dynamics and heat transfer in turbulent channel flow
Authors: Deng Yifan , Tang Yuchao , Wang Peng , Cao Zhaomin , Liu Yingzheng
Published: January 2022

The fluid–structure–thermal interaction of tandem fluttering membranes with gap distance ratios ranging from D*=1.0 to 4.0 in turbulent channel flow at Reynolds number ReL = 2.05×104 was investigated. Three distinct coupling modes (strong, medium, and weak, with D*=1.0, 1.5, and 2.0, respectively) of the tandem membranes were compared. The coupled fluttering motions and output voltages of the tandem membranes were recorded simultaneously. The two tandem membranes fluttered at the same frequency but different amplitudes. The flutter amplitude of the rear membrane, enhanced by the front membrane, exhibited the largest and smallest values in the strong and weak coupling modes, respectively. The phase difference Δϕ was linearly dependent on D*. Furthermore, the statistical flow quantities and heat transfer performance were examined. As D* increased from 1.0 to 2.0, only minor variations occurred in the streamwise and vertical velocities, leading to a decreased pressure loss and enhanced heat transfer. Moreover, the largest thermal enhancement factor was attained in the strong coupling mode owing to the large space-averaged Nusselt number. Finally, a membrane-shape-identification method was used to capture the spatiotemporal evolutions of the flow–structure dynamics. The decrease in the pressure loss and enhancement in the heat transfer of the tandem fluttering membranes were clarified by investigating the spatiotemporal evolutions of the unsteady flow behaviors. This study may offer an important reference for the designing of an efficient heat transfer device using multiple membranes.
A predictive model for macro-performances applied to laser-assisted pulsed plasma thrusters
Authors: Ou Yang , Wu Jianjun , Zhang Yu , Zhao Yuanzheng
Published: January 2022

The laser-assisted pulsed plasma thruster is considered a promising propulsion system to support the tasks of microsatellites because of its high specific impulse and low volume. Different from the traditional pulsed plasma thruster, laser-assisted pulsed plasma thruster uses the laser to replace the spark plug for ignition, which can avoid ignition failure and remove the side effect of carbon deposition. Both the thrust efficiency and impulse bit are expected to increase after the plasma flow produced by laser ablation is further ionized and accelerated. Since there are a few macro-performance prediction models in laser-assisted pulsed plasma thrusters, this paper develops a model based on the laser ablation model and electromagnetic acceleration model to capture macro-performances of laser-assisted pulsed plasma thrusters. In this model, the initial velocity and mass of plasma flow can be obtained from the ablation model, and the acceleration model is utilized to describe the electromagnetic acceleration process of plasma flow. With this combined model, the discharge current, voltage, impulse bit, specific impulse, and thrust efficiency can be estimated. The deviation between the predicted results and experimental results was less than 10%, verifying the correctness of the developed model. The effects of different parameters on the performance are further investigated with this model.
Study on near-field acoustic levitation characteristics in a pressurized environment
Authors: Li Ronghe , Li Yifei , Sang Hande , Liu Yuanyuan , Chen Shuang , Zhao Su
Published: January 2022

The influence of the ambient pressure on the load capacity of near-field acoustic levitation is studied. Theoretical models based on the acoustic radiation pressure and hydrodynamic lubrication theory are built, taking into account the changes of the ambient pressure. Both simulation and measured results show that the levitation force is positively proportional to the ambient pressure. The levitation force increased by 4–5 times at an ambient pressure of 0.5 MPa. A maximum load capacity of 0.309 MPa is obtained.
Nonlinear transmission line (NTL) model study of electromagnetic effects in high-frequency asymmetrically driven capacitive discharges
Authors: Liu Jian-Kai , Kawamura Emi , Lieberman Michael A. , Wang You-Nian
Published: January 2022

In this work, we generalize a nonlinear transmission line (NTL) model introduced in a previous work [Liu et al. Plasma Sources Sci. Technol. 30, 045017 (2021)] to achieve more comprehensive simulations. The improved NTL model allows a variable-sized (instead of a one grid cell) vacuum spacer between the powered and grounded electrodes and takes into account the (previously neglected) electron-neutral elastic collision frequency term in the plasma dielectric constant, and the radial variation of the plasma density. Using this model, we study the effects of the spatial and series resonances, associated with the (axially) z-antisymmetric and z-symmetric radially propagating surface wave modes, and the nonlinear harmonic excitations on the plasma uniformity. We conduct simulations in which we increase the driving frequency f from 30 to 120 MHz for an asymmetric capacitive argon discharge at a fixed pressure and electron power of pg=20 mTorr and Pe=40 W, respectively. The first antisymmetric mode resonance frequency fa1 occurs between 80 and 90 MHz, and the first symmetric mode resonance frequency fs1 occurs at about 100 MHz. The powered electrode sheath becomes smaller than the grounded electrode sheath for f≈fa1, and the source voltage reaches a minimum for f≈fs1. The radially varying electron power density shows a narrow center peak due to the finite mode wavelengths and the nonlinearly excited harmonics, which can be further enhanced by spatial or series resonances. A second peak appears above the vacuum spacer edge as f exceeds fs1 at 120 MHz because the shorter wavelengths at higher f allow secondary maxima of the surface waves to form within the reactor.
Inhomogeneous plasma electron density inversion based on Bayesian regularization neural network
Authors: Gan Liping , Guo Lixin , Guo Linjing , Li Jiangting
Published: January 2022

Electron density is one of the most important parameters for characterizing plasma properties, so obtaining accurate electron density is a prerequisite for studying the interaction between plasma and the electromagnetic waves. This paper presents the effects of different electron densities on the electric field distribution of a microstrip antenna with a center frequency of 2.45 GHz. Then, on the basis of the integrated model of plasma and the microstrip antenna, the Bayesian regularization neural network (BRNN) is used to retrieve the electron density of inhomogeneous plasma. Furthermore, the performance of the proposed approach is evaluated and analyzed by comparison with Levenberg–Marquardt (LM) and Scaled Conjugate Gradient (SCG) neural networks. The results show that the BRNN provides better performance than LM and SCG neural networks to retrieve plasma electron density based on the electric field intensity at fewer spatial positions. The accurate distribution of the electron density of inhomogeneous plasma can be obtained using BRNN. In addition, the greater the range variation of electron density, the greater the relative inversion error. This study provides an important theoretical basis for the diagnosis of electron density for inhomogeneous plasma in experiments.
Hydrodynamic behavior of a circular floating solar pond with an entrapped two-layer fluid
Authors: Han Jian , Zhang Xinshu , Yeung Ronald W.
Published: January 2022

The resonant behavior in a moonpool of a floating circular solar pond, with an entrapped two-layer fluid, is studied. The problem is solved by applying a domain-decomposition method using eigenfunction matching. The surface- and internal-wave elevations and the hydrodynamic coefficients of a typical floating solar pond under forced heave or surge motion are computed. The effects of density stratification on surface-wave elevation, added mass, and damping coefficients are analyzed. A collection of resonance frequencies of surface and internal waves is examined, together with the corresponding variations of modal shapes. For heave resonance, the surface and internal waves are characterized by axisymmetric sloshing modes, as opposed to antisymmetric sloshing modes under surge resonances. A frozen-mode approximation method that treats the moonpool fluid as a density-stratified solid is developed to estimate piston-mode frequencies. Non-dimensional resonance frequencies corresponding to antisymmetric and axisymmetric sloshing modes are estimated based on the standing-wave approximation and reciprocity relations between surface and internal wavenumbers. Satisfactory agreement between the estimated resonance frequencies and those computed by eigenfunction matching method is achieved. It is found that the first resonance of the internal wave, rather than higher-order resonances, is more likely to affect the surface-wave behavior, whereas resonances of the surface-wave modes have significant effects on the internal waves. Parametric analyses are performed to study the effects of geometry configurations of the pond. It is found that the resonance frequencies of internal waves under forced heave or surge motion decrease with an increasing density ratio.
Evolutionary clustering of Lagrangian trajectories in turbulent Rayleigh–Bénard convection flows
Authors: Schneide Christiane , Vieweg Philipp P. , Schumacher Jörg , Padberg-Gehle Kathrin
Published: January 2022

We explore the transport mechanisms of heat in two- and three-dimensional turbulent convection flows by means of the long-term evolution of Lagrangian coherent sets. They are obtained from the spectral clustering of trajectories of massless fluid tracers that are advected in the flow. Coherent sets result from trajectories that stay closely together under the dynamics of the turbulent flow. For longer times, they are always destroyed by the intrinsic turbulent dispersion of material transport. Here, this constraint is overcome by the application of evolutionary clustering algorithms that add a time memory to the coherent set detection and allows individual trajectories to leak in or out of evolving clusters. Evolutionary clustering thus also opens the possibility to monitor the splits and mergers of coherent sets. These rare dynamic events leave clear footprints in the evolving eigenvalue spectrum of the Laplacian matrix of the trajectory network in both convection flows. The Lagrangian trajectories reveal the individual pathways of convective heat transfer across the fluid layer. We identify the long-term coherent sets as those fluid flow regions that contribute least to heat transfer. Thus, our evolutionary framework defines a complementary perspective on the slow dynamics of turbulent superstructure patterns in convection flows that were recently discussed in the Eulerian frame of reference. The presented framework might be well suited for studies in natural flows, which are typically based on sparse information from drifters and probes.
Space-warp coordinate transformation for efficient ionic force calculations in quantum Monte Carlo
Authors: Nakano Kousuke , Raghav Abhishek , Sorella Sandro
Published: January 2022

Ab initio quantum Monte Carlo (QMC) methods are a state-of-the-art computational approach to obtaining highly accurate many-body wave functions. Although QMC methods are widely used in physics and chemistry to compute ground-state energies, calculation of atomic forces is still under technical/algorithmic development. Very recently, force evaluation has started to become of paramount importance for the generation of machine-learning force-field potentials. Nevertheless, there is no consensus regarding whether an efficient algorithm is available for the QMC force evaluation, namely, one that scales well with the number of electrons and the atomic numbers. In this study, we benchmark the accuracy of all-electron variational Monte Carlo (VMC) and lattice-regularized diffusion Monte Carlo (LRDMC) forces for various mono- and heteronuclear dimers (1 ≤ Z ≤ 35, where Z is the atomic number). The VMC and LRDMC forces were calculated with and without the so-called space-warp coordinate transformation (SWCT) and appropriate regularization techniques to remove the infinite variance problem. The LRDMC forces were computed with the Reynolds (RE) and variational-drift (VD) approximations. The potential energy surfaces obtained from the LRDMC energies give equilibrium bond lengths (req) and harmonic frequencies (ω) very close to the experimental values for all dimers, improving the corresponding VMC results. The LRDMC forces with the RE approximation improve the VMC forces, implying that it is worth computing the DMC forces beyond VMC despite the higher computational cost. The LRDMC forces with the VD approximations also show improvement, which unfortunately comes at a much higher computational cost in all-electron calculations. We find that the ratio of computational costs between QMC energy and forces scales as Z∼2.5 without the SWCT. In contrast, the application of the SWCT makes the ratio independent of Z. As such, the accessible QMC system size is not affected by the evaluation of ionic forces but governed by the same scaling as the total energy one.
Search for long-lasting electronic coherence using on-the-fly ab initio semiclassical dynamics
Authors: Scheidegger Alan , Vaníček Jiří , Golubev Nikolay V.
Published: January 2022

Using a combination of high-level ab initio electronic structure methods with efficient on-the-fly semiclassical evaluation of nuclear dynamics, we performed a massive scan of small polyatomic molecules searching for a long-lasting oscillatory dynamics of the electron density triggered by the outer-valence ionization. We observed that in most of the studied molecules, either the sudden removal of an electron from the system does not lead to the appearance of the electronic coherence or the created coherences become damped by the nuclear rearrangement on a time scale of a few femtoseconds. However, we report several so far unexplored molecules with the electronic coherences lasting up to 10 fs, which can be good candidates for experimental studies. In addition, we present the full-dimensional simulations of the electronic coherences coupled to nuclear motion in several molecules which were studied previously only in the fixed nuclei approximation.
Deterministic modeling of hybrid nonlinear effects in epsilon-near-zero thin films
Authors: Secondo R. , Ball A. , Diroll B. , Fomra D. , Ding K. , Avrutin V. , Özgür Ü. , Demchenko D. O. , Khurgin J. B. , Kinsey N.
Published: January 2022

In nonlinear optics, significant effort is concentrated on improving the strength and efficiency of interactions; however, experimentally investigating nonlinear materials is a complex, time-consuming, and costly investment. Moreover, it is often challenging to isolate, study, and optimize material parameters in an experiment due to complexities in the growth process. Recently, epsilon-near-zero materials have received a great deal of attention as promising nonlinear optical materials, but like many up-and-coming materials, the ability to explore and optimize their properties has been challenging. Here, we establish a framework to rapidly evaluate the performance of nonlinear epsilon-near-zero materials for both inter- and intraband effects in silico, requiring only an energy–momentum (E–k) diagram, linear optical properties, and experimental conditions. Measured nonlinear reflection and transmission in gallium-doped zinc oxide films are compared to the numerical framework for both intra- and interband excitation to verify accuracy across wavelength and irradiance while two figures of merit (FoMs) are introduced to quickly evaluate the performance of films without a full numerical framework. This capability is used to predict the performance of highly doped gallium nitride, cadmium oxide, zinc oxide, and indium tin oxide films, and efficient intra- and interband operation conditions are identified. Through this numerical framework and the FoMs, the exploration of unstudied epsilon-near-zero materials is enabled without the need for a nonlinear experiment, thereby accelerating the search for more efficient nonlinear materials and excitation conditions.
Generalized approach to plasmonic phase modulation in topological bi-gratings
Authors: Fox Maayan , Gorodetski Yuri
Published: January 2022

We study the role of optical momenta in surface plasmon excitation by topological bi-gratings. We analyze plasmonic structures composed of rectangular apertures rotating in 2D space with given rates, which couple to specific plasmon trajectories. We experimentally demonstrate the control of plasmonic propagation through premeditated design of the gratings, which interact with linear, spin, and orbital angular momentum of light. We show that these trajectories can be selected purely through momenta modulation with numerous degrees of freedom for a given structure geometry. Moreover, it is shown that the symmetry of the final plasmonic distribution is defined by selecting specific rotation rates, and that it can be different from the original grating symmetry.
Spray characteristics of diesel, biodiesel, polyoxymethylene dimethyl ethers blends and prediction of spray tip penetration using artificial neural network
Authors: Liu Yu , Tian Junjian , Song Zhihui , Li Fengyu , Zhou Wenliang , Lin Qizhao
Published: January 2022

Biodiesel and polyoxymethylene dimethyl ethers (PODE) are both alternative fuels with great potential. The spray characteristics of D100 (neat diesel), DP20 (80 vol. % diesel and 20 vol. % PODE), B100 (neat biodiesel), and BP20 (80 vol. % biodiesel and 20 vol. % PODE) under different injection pressures were investigated in a constant volume combustion chamber. The results show that the spray tip penetration of biodiesel blends is greater than that of diesel blends, and the penetration of DP20 is larger than that of D100, while the difference between BP20 and B100 is not significant. The spray cone angle, spray projected area, and liquid core area of biodiesel blends are smaller than that of diesel blends. Due to the low viscosity of PODE, the addition of PODE can increase the spray cone angle, spray projected area, and liquid core area of both diesel and biodiesel. The effect of PODE on biodiesel makes its spray characteristics close to that of pure diesel, which provides convenience for the application of biodiesel in conventional diesel engines. At the same time, computer technology was used to develop the best artificial neural network (ANN) model to predict the spray tip penetration of different fuels. The root mean square error of the model is as low as 0.343 938 mm, and the coefficient of determination is 0.999 737 5, indicating that the model has excellent predictive performance. Finally, to increase the application range of the ANN model, the mathematical expression of the spray tip penetration corresponding to the model was given.
Twist angle dependent electronic properties in 2D graphene/MoS2 vdW heterostructures
Authors: Wang Jicui , Ge Mei , Ma Rongrong , Sun Yun , Cheng Liyuan , Wang Rui , Guo Miaomiao , Zhang Junfeng
Published: January 2022

Two-dimensional (2D) heterostructures constructed by different 2D materials offer new opportunities for novel nano-devices. Twist angle (θ) between two individual layers in 2D van der Waals (vdW) heterostructures shows great importance in modulating their electronic properties. Here, we performed first-principles calculations to study the thermodynamic stability and electronic properties of graphene/MoS2 (Gr/MoS2) vdW heterostructures. We have built dozens of possible Gr/MoS2 vdW heterostructures under the limitation of the maximum mismatch (δ ≤ 2.5%) and supercell lattice (≤20 Å). We found the cohesive energy (Ecoh) is dependent on the interlayer distance and θ. In addition, a huge difference can be found in both the band offset and interlayer carrier's lifetime of Gr/MoS2 with different θ. These results provide valuable insights into the identification of these twist structures in experiments and the designation of Gr/MoS2 related optoelectronic devices.
Reduced-order modeling for turbulent wake of a finite wall-mounted square cylinder based on artificial neural network
Authors: Yousif Mustafa Z. , Lim Hee-Chang
Published: January 2022

This study presents an artificial neural network and a proper orthogonal decomposition (POD)-based reduced-order model (ROM) of turbulent flow around a finite wall-mounted square cylinder. The proposed model is suitable for turbulent wake control applications, because it can predict the dynamics of the main features of the flow field with low computational cost. A long short-term memory neural network (LSTM NN) and a bidirectional long short-term memory neural network (BLSTM NN) are used to predict the temporal evolution of POD time coefficients at different sections along the height of the obstacle. The improved delayed detached-eddy simulation is performed to generate training datasets. Transfer learning is utilized in the training process by using the weights of the LSTM/BLSTM NN that are used to predict the POD time coefficients of the planes at lower elevations to initialize the weights of the networks at higher elevations along the height of the obstacle. The use of transfer learning results in a remarkable improvement in the prediction capability of LSTM/BLSTM NN compared with the one when the network is initialized with random weights. The BLSTM NN shows better results compared with the LSTM NN in terms of training and prediction error, indicating that the BLSTM-POD model is more suitable to be used as a ROM for predicting the turbulent wake. Furthermore, the temporal evolution of the time coefficients is carefully examined using the phase space plots and Poincaré sections. The results of using different lengths of the prediction time window show that the prediction error of the POD time coefficients increases as the prediction time window increases and the error increasing rate decreases with ranking of the POD modes.
The effect of annealing on photoluminescence from defects in ammonothermal GaN
Authors: Reshchikov M. A. , Demchenko D. O. , Ye D. , Andrieiev O. , Vorobiov M. , Grabianska K. , Zajac M. , Nita P. , Iwinska M. , Bockowski M. , McEwen B. , Shahedipour-Sandvik F.
Published: January 2022

Ammonothermal GaN samples with the concentration of free electrons of 1018 and 1019 cm−3 were annealed in a wide range of temperatures (Tann = 300–1400 °C) under atmospheric N2 pressure and under ultra-high N2 pressure conditions to avoid the GaN decomposition. Photoluminescence (PL) studies reveal the YL2 band with a maximum at 2.3 eV before annealing and two new PL bands after annealing at Tann > 600 °C: the OL3 band with a maximum at 2.1 eV and the RL4 band with a maximum at 1.6–1.7 eV. The ammonothermal GaN samples have high concentrations of complexes containing gallium vacancy (VGa), hydrogen, and oxygen. The first-principles calculations suggest that the VGa-3Hi complex is the origin of the YL2 band, while the VGa-3ON complex is responsible for the RL4 band.
Atomistic simulations on the relationship between solid-phase epitaxial recrystallization and self-diffusion in amorphous silicon
Authors: Posselt M. , Bracht H. , Radić D.
Published: January 2022

Recent experimental results on self-diffusion (SD) in amorphous silicon (a-Si) [Kirschbaum et al., Phys. Rev. Lett. 120, 225902 (2018)] indicate that the atomic mechanism of this process is akin to that of solid-phase epitaxial recrystallization (SPER). In the present work, this relationship is investigated using classical molecular dynamics (MD) simulations with selected interatomic potentials. In the beginning, an overview of the status of the present knowledge on SPER and SD is given. Then, it is shown that the Stillinger–Weber (SW)-type and Tersoff (T)-type potentials considered yield structural data of a-Si, which are in rather good agreement with measurements. On the other hand, deviations are found for thermal properties. The results of partially extremely long MD calculations of SPER and SD yield that both processes can be described by a simple Arrhenius relation and that the activation enthalpies of SPER and SD are rather equal, which is in qualitative agreement with experiments. Obviously, the simulated atomic-level processes are very similar. However, for the known SW- and T-type interatomic potentials, a quantitative agreement with SPER and SD measurements cannot be found. This work demonstrates that significant improvements can be achieved if SW-type potentials with an increased value of the three-body parameter are used.
Lateral migration of viscoelastic capsules in tube flow
Authors: Rezghi Ali , Li Ping , Zhang Junfeng
Published: January 2022

In this article, the lateral migration process of a viscoelastic capsule of spherical original shape in a tube flow is simulated. The capsule membrane follows the Skalak constitutive law for elasticity, and the membrane viscosity is modeled using the recently developed finite difference scheme. The methodology is validated carefully by simulating the tank-treading motion of an elastic capsule in shear flow. The lateral migration of viscoelastic capsules is then investigated in detail with various combinations of viscosity ratio, membrane shear viscosity, and capillary number. In general, the migration process starts with an initial transient phase, where the capsule deformation and migration velocity suddenly increase from zero to a maximum value. Following that, the deformation and migration velocity gradually reduce as the capsule moves toward the tube centerline. The capsule also performs continuous rotation during the migration, and the rotation gradually slows down with the capsule migration. The interior-exterior fluid viscosity contrast and the membrane viscosity have similar effects in reducing the capsule deformation and inclination angle to the flow direction; however, a strong membrane viscosity may introduce significant oscillations in the capsule deformation, inclination, and migration velocity. Due to the reduced capsule deformation, the migration velocity and capsule rotation become slower for capsules with higher viscosity contrast and/or membrane viscosity. Moreover, the influence of membrane viscosity on the migration dynamics intensifies at higher capillary number. Finally, empirical correlations are proposed for the migration velocity and rotation period, and the proposed relations match fairly well the simulation results, which cover wide ranges of system parameters. The discussions and analysis could be valuable for better understanding the complicated flow–capsule interaction and capsule dynamics in the migration process.
Photoluminescence and minority carrier lifetime of quinary GaInAsSbBi grown on GaSb by molecular beam epitaxy
Authors: Carrasco Rigo A. , Morath Christian P. , Logan Julie V. , Woller Kevin B. , Grant Perry C. , Orozco Haylie , Milosavljevic Marko S. , Johnson Shane R. , Balakrishnan Ganesh , Webster Preston T.
Published: January 2022

Quinary GaInAsSbBi is grown by molecular beam epitaxy, and the alloy is demonstrated with a bandgap energy of 291 meV (λcutoff ∼ 4.3 μm) and a minority carrier lifetime of 0.34 μs at 120 K. The GaInAsSbBi epilayer is grown to a thickness of 1 μm at 400 °C and lattice-matched to the GaSb substrate with a Bi mole fraction of 0.13% measured by Rutherford backscattering spectroscopy. Steady-state and time-resolved photoluminescence measurements are performed to gauge the comparative bandgaps and optical quality of GaInAsSbBi as well as InAsSbBi and GaInAsSb reference samples. A recombination rate analysis is performed on the low-injection temperature-dependent minority carrier lifetime to extract the Shockley–Read–Hall defect level and intrinsic doping concentration of the GaInAsSbBi.
Patterned optical anisotropic film for generation of non-diffracting vortex beams
Authors: Duan Wei , Ma Ling-Ling , Chen Peng , Hu Wei , Wang Qiong-Hua , Lu Yan-Qing
Published: January 2022

Bessel vortex beams (BVBs) are endowed with non-diffracting properties and carry specific orbital angular momentum, which adds a new degree of freedom in the manipulation of light. A patterned liquid crystal polymer (LCP)-based optical anisotropic film is proposed and demonstrated for generation of non-diffracting BVBs. The optical axis distribution is induced by the functionalized film, which can simultaneously modulate the amplitude and phase of the wavefront. Different BVB modes can be obtained in this manner. The topological charges and non-diffracting properties of the BVBs are experimentally verified. The multifunctional LCP film exhibits the merits of low power consumption, low cost, and easy fabrication. It may provide a new strategy for beam shaping and planar optics.
Photoelectron circular dichroism of a model chiral anion
Authors: Artemyev Anton N. , Kutscher Eric , Demekhin Philipp V.
Published: January 2022

Photoelectron circular dichroism (PECD) in the one-photon detachment of a model chiral anionic system is studied theoretically by the single center method. The computed chiral asymmetry, characterized by the dichroic parameter β1 of up to about ±3%, is in good accord with the first experimental observations of the effect in photodetachment of amino acid anions [P. Krüger and K. M. Weitzel, Angew. Chem., Int. Ed. 60, 17861 (2021)]. Our findings confirm a general assumption that the magnitude of PECD is governed by the ability of an outgoing photoelectron wave packet to accumulate characteristic chiral asymmetry from the short-range part of the molecular potential.
Downstream semi-circular obstacles' influence on floods arising from the failure of dams with different levels of reservoir silting
Authors: Vosoughi Foad , Nikoo Mohammad Reza , Rakhshandehroo Gholamreza , Adamowski Jan Franklin , Gandomi Amir H.
Published: January 2022

Dam-break wave propagation in a debris flood event is strongly influenced by accumulated reservoir-bound sediment and downstream obstacles. For instance, the Brumadinho dam disaster in Brazil in 2019 released 12 × 106 m3 of mud and iron tailings and inflicted 270 casualties. The present work was motivated by the apparent lack of experimental or numerical studies on silted-up reservoir dam-breaks with downstream semi-circular obstacles. Accordingly, 24 dam-break scenarios with different reservoir sediment depths and with or without obstacles were observed experimentally and verified numerically. Multiphase flood waves were filmed, and sediment depths, water levels, and values of front wave celerity were measured to improve our scientific understanding of shock wave propagation over an abruptly changing topography. Original data generated in this study is available online in the public repository and may be used for practical purposes. The strength of OpenFOAM software in estimating such a complex phenomenon was assessed using two approaches: volume of fluid (VOF) and Eulerian. An acceptable agreement was attained between numerical and experimental records (errors ranged from 1 to 13.6%), with the Eulerian outperforming the VOF method in estimating both sediment depth and water level profiles. This difference was most notable when more than half of the reservoir depth was initially filled by sediment (≥0.15 m), particularly in bumpy bed scenarios.
Synchronization in Hindmarsh–Rose neurons subject to higher-order interactions
Authors: Parastesh Fatemeh , Mehrabbeik Mahtab , Rajagopal Karthikeyan , Jafari Sajad , Perc Matjaž
Published: January 2022

Higher-order interactions might play a significant role in the collective dynamics of the brain. With this motivation, we here consider a simplicial complex of neurons, in particular, studying the effects of pairwise and three-body interactions on the emergence of synchronization. We assume pairwise interactions to be mediated through electrical synapses, while for second-order interactions, we separately study diffusive coupling and nonlinear chemical coupling. For all the considered cases, we derive the necessary conditions for synchronization by means of linear stability analysis, and we compute the synchronization errors numerically. Our research shows that the second-order interactions, even if of weak strength, can lead to synchronization under significantly lower first-order coupling strengths. Moreover, the overall synchronization cost is reduced due to the introduction of three-body interactions if compared to pairwise interactions.
Mode selective excitation of spin waves
Authors: Taniguchi Takuya , Back Christian H.
Published: January 2022

Spin waves propagating in a waveguide have eigenmodes depending on the standing waves formed in the perpendicular direction. Although it is functional to excite high order spin wave modes, it has been difficult to excite a high order spin wave mode selectively. In this work, we numerically investigated spin wave excitation in a T-shaped magnetic device, and we consequently found that even high order spin wave modes are selectively excited by optimizing the frequency and the dimension of the T-shaped structure.
Accurate storm surge forecasting using the encoder–decoder long short term memory recurrent neural network
Authors: Bai Long-Hu , Xu Hang
Published: January 2022

The encoder–decoder LSTM (long short term memory) recurrent neural network is proposed to predict storm surge in Florida. Two types of hurricanes with six events are collected for training and testing. The previously observed meteorological data including the storm surge, the wind speed, the wind gust, the barometric pressure, and the air temperature are chosen as the inputs of model, while the future storm surge is designated as the output. The predicted results for 1, 3, 6, 9, and 12 h-lead time are obtained. Four indices are introduced to evaluate the accuracy and stability of the proposed model. Through comparing the predicted results by both models with the observed data, it is found that the encoder–decoder LSTM approach is more accurate than the convolutional neural network model for all considered cases. Furthermore, we notice that the combinations of storm surge, wind speed, wind gust, barometric pressure, and air temperature, and storm surge and wind speed give the best prediction for the first and the second types of hurricanes, respectively. Our work suggests that the encoder–decoder LSTM model has great potential in storm surge prediction. It is expected that the accuracy of this model can be further improved by introducing more observed data and considering more physical factors.
Difficult climate-adaptive decisions in forests as complex social–ecological systems
Authors: Findlater Kieran , Kozak Robert , Hagerman Shannon
Published: January 2022

Significance

New forest management techniques, like genomics-based assisted migration (AM), can help forests adapt to climate change by maintaining the productivity of commercially important tree species. However, we find that key stakeholder groups tend to be more concerned about the broader health of the forest ecosystem than the success of commercially important species. Because of its uncertain impact on other social, ecological, and economic goals, they have difficulty judging the acceptability of AM and the trade-offs that it implies. While AM may appear to be a technical intervention, many of its implications are not. Decisions about AM and other such adaptations should account for the breadth of values that forests create and the diverse voices of those who depend on them.
Celebrating 20 years of live single-actin-filament studies with five golden rules
Authors: Wioland Hugo , Jégou Antoine , Romet-Lemonne Guillaume
Published: January 2022

The precise assembly and disassembly of actin filaments is required for several cellular processes, and their regulation has been scrutinized for decades. Twenty years ago, a handful of studies marked the advent of a new type of experiment to study actin dynamics: using optical microscopy to look at individual events, taking place on individual filaments in real time. Here, we summarize the main characteristics of this approach and how it has changed our ability to understand actin assembly dynamics. We also highlight some of its caveats and reflect on what we have learned over the past 20 years, leading us to propose a set of guidelines, which we hope will contribute to a better exploitation of this powerful tool.
Eosinophils regulate intra-adipose axonal plasticity
Authors: Meng Xia , Qian Xinmin , Ding Xiaofan , Wang Wenjing , Yin Xia , Zhuang Guanglei , Zeng Wenwen
Published: January 2022

Significance

Neuronal innervation in the adipose tissues plays a crucial role in regulating adipose thermogenic capacity and metabolic homeostasis. The tissue-wide nerves display a large extent of structural plasticity under physiological and pathological conditions that alter the neuronal control of metabolic states. We find here that neuronal plasticity is regulated by immune cells, which constitutes an appealing way to reshape neural-controlled energy balance by targeting immune components.
Integrated genome and transcriptome analyses reveal the mechanism of genome instability in ataxia with oculomotor apraxia 2
Authors: Kanagaraj Radhakrishnan , Mitter Richard , Kantidakis Theodoros , Edwards Matthew M. , Benitez Anaid , Chakravarty Probir , Fu Beiyuan , Becherel Olivier , Yang Fengtang , Lavin Martin F. , Koren Amnon , Stewart Aengus , West Stephen C.
Published: January 2022

Significance

Ataxia with oculomotor apraxia (AOA) is a progressive neurodegenerative disease characterized by early‐onset autosomal recessive cerebellar ataxia with oculomotor apraxia, peripheral axonal neuropathy, and impaired motor functions. The AOA-2 subgroup results from mutations in an RNA/DNA helicase, Senataxin, which is encoded by the
SETX
gene. Here, we carried out integrated genome and transcriptome analyses of cell lines derived from individuals with AOA2, as well as CRISPR/Cas9 generated
SETX
knockouts, and observed genome-wide chromosome fragility. Genome instability was caused by increased transcription stress and the accumulation of RNA/DNA hybrids near gene promotors, resulting in aberrant DNA repair that led to changes in gene-expression profiles. The results indicate that
SETX
-defective cells exhibit transcription stress that leads to chromosome fragility.
Mitoribosomal small subunit maturation involves formation of initiation-like complexes
Authors: Lenarčič Tea , Niemann Moritz , Ramrath David J. F. , Calderaro Salvatore , Flügel Timo , Saurer Martin , Leibundgut Marc , Boehringer Daniel , Prange Céline , Horn Elke K. , Schneider André , Ban Nenad
Published: January 2022

Mitochondrial ribosomes (mitoribosomes) play a central role in synthesizing
mitochondrial inner membrane proteins responsible for oxidative phosphorylation.
Although mitoribosomes from different organisms exhibit considerable structural
variations, recent insights into mitoribosome assembly suggest that mitoribosome
maturation follows common principles and involves a number of conserved assembly
factors. To investigate the steps involved in the assembly of the mitoribosomal
small subunit (mt-SSU) we determined the cryoelectron microscopy structures of
middle and late assembly intermediates of the
Trypanosoma brucei
mitochondrial small subunit (mt-SSU) at 3.6- and 3.7-Å resolution,
respectively. We identified five additional assembly factors that together with
the mitochondrial initiation factor 2 (mt-IF-2) specifically interact with
functionally important regions of the rRNA, including the decoding center,
thereby preventing premature mRNA or large subunit binding. Structural
comparison of assembly intermediates with mature mt-SSU combined with RNAi
experiments suggests a noncanonical role of mt-IF-2 and a stepwise assembly
process, where modular exchange of ribosomal proteins and assembly factors
together with mt-IF-2 ensure proper 9S rRNA folding and protein maturation
during the final steps of assembly.
Sequence locally, think globally: The Darwin Tree of Life Project
Authors:   The Darwin Tree of Life Project Consortium, Blaxter Mark , Mieszkowska Nova , Di Palma Federica , Holland Peter , Durbin Richard , Richards Thomas , Berriman Matthew , Kersey Paul , Hollingsworth Peter , Wilson Willie , Twyford Alex , Gaya Ester , Lawniczak Mara , Lewis Owen , Broad Gavin , Howe Kevin , Hart Michelle , Flicek Paul , Barnes Ian
Published: January 2022

The goals of the Earth Biogenome Project—to sequence the genomes of all eukaryotic life on earth—are as daunting as they are ambitious. The Darwin Tree of Life Project was founded to demonstrate the credibility of these goals and to deliver at-scale genome sequences of unprecedented quality for a biogeographic region: the archipelago of islands that constitute Britain and Ireland. The Darwin Tree of Life Project is a collaboration between biodiversity organizations (museums, botanical gardens, and biodiversity institutes) and genomics institutes. Together, we have built a workflow that collects specimens from the field, robustly identifies them, performs sequencing, generates high-quality, curated assemblies, and releases these openly for the global community to use to build future science and conservation efforts.
V-CARMA: A tool for the detection and modification of antigen-specific T cells
Authors: Guo Xi-zhi J. , Elledge Stephen J.
Published: January 2022

Significance

Immunotherapy is a promising approach to treat cancers, infectious diseases, and autoimmunity by harnessing the power of immune cells, especially T cells. To improve the precision and efficacy of immunotherapy, the ability to genetically modify antigen-specific T cells is needed but cannot be accomplished using current methods. Here, we present a method, V-CARMA (Viral ChimAeric Receptor MHC-Antigen), to generate lentiviruses displaying peptide-MHC complex to specifically target T cells that express cognate TCRs and subsequently deliver genes into target T cells for genetic modification. Our results demonstrate that V-CARMA is a versatile tool to detect and modify antigen-specific T cells.
Politicians polarize and experts depolarize public support for COVID-19 management policies across countries
Authors: Flores Alexandra , Cole Jennifer C. , Dickert Stephan , Eom Kimin , Jiga-Boy Gabriela M. , Kogut Tehila , Loria Riley , Mayorga Marcus , Pedersen Eric J. , Pereira Beatriz , Rubaltelli Enrico , Sherman David K. , Slovic Paul , Västfjäll Daniel , Van Boven Leaf
Published: January 2022

Significance

Political polarization impeded public support for policies to address the spread of COVID-19, much as polarization hinders responses to other societal challenges. The present cross-country study demonstrates how the cues from political elites and affective polarization are analogous across countries addressing COVID-19. Far from being an outlier, the United States faces polarization challenges similar to those of other countries. Importantly, the results demonstrate that policies to combat public health crises are more supported when proposed by nonpartisan experts and bipartisan coalitions of political leaders. These results provide clear guidance on depolarizing communication strategies to improve global responses to health crises.
Longitudinal clonal dynamics of HIV-1 latent reservoirs measured by combination quadruplex polymerase chain reaction and sequencing
Authors: Cho Alice , Gaebler Christian , Olveira Thiago , Ramos Victor , Saad Marwa , Lorenzi Julio C. C. , Gazumyan Anna , Moir Susan , Caskey Marina , Chun Tae-Wook , Nussenzweig Michel C.
Published: January 2022

Significance

HIV-1 infection requires lifelong treatment with antiretroviral therapy (ART) due to viral rebound of a latent reservoir of intact, transcriptionally silent provirus found to persist in the genome of CD4
+
T cells. One major challenge to understanding the nature of the latent reservoir is accurately characterizing the measuring of the size of the reservoir. Herein, we use quadruplex polymerase chain reaction (Q4PCR) to assess the dynamics of the latent reservoir in HIV
+
individuals who have been on long-term ART for up to 10 y. Our results show that Q4PCR can be used to accurately measure the latent reservoir, while providing the added benefit of assessing the genetic diversity of the reservoir to better understand changes to clonal dynamics over time.
Dynamic multifunctional devices enabled by ultrathin metal nanocoatings with optical/photothermal and morphological versatility
Authors: Zeng Songshan , Yang Zhuoran , Hou Zaili , Park Cheonjin , Jones Michael D. , Ding Hao , Shen Kuangyu , Smith Andrew T. , Jin Henry X. , Wang Bing , Jiang Han , Sun Luyi
Published: January 2022

Significance

Smart devices characterized by micro-/nanotopographies, such as cracks, wrinkles, folds, etc., have been fabricated for widespread application. Here, with the combination of multiscale hierarchical architecture, ultrathin metal nanocoatings with high optical/photothermal tunability and morphological versatility, and surface/interface engineering, a set of multifunctional devices with multistimuli responsiveness was fabricated. These devices can adapt to external stimuli with reversible and instantaneous responses in optical signals, which include strain-regulated light-scattering properties, photothermal-responsive wrinkled surface coupled with moisture-responsive structural color, and mechanically controllable light-shielding properties. The structural designs that rationally overlay micro-/nanostructured ultrathin nanocoatings with other elements are the key to realize this advanced system, which provides avenues for designing versatile, tunable, and adaptable multifunctional devices.
Electropulsing-induced plastic deformation in an interstitial free steel
Authors: Raut P. , Fuloria D. , Baka S. , Chatterjee S. , Ghosh C. , Venkatramani N. , Samajdar I.
Published: January 2022

Direct observations on electropulsing (EP)-induced microstructural evolution, in interstitial free (IF) steel with different prior rolling reductions, brought out clear evidence of plastic deformation, changes in mesostructures and local mechanical properties. Although plastic strains and strain modes differed widely among the surface grains, these appeared orientation-dependent. In particular, the microstructural evolution was more pronounced when prior cold work was present and also along the transverse direction to the introduced EP. Finite element simulations showed a significant difference in locational and directional dependence of simulated magnetic flux density and stored magnetic energy. It appears that magnetic Lorentz force, providing torque to dislocation dipoles, acted as the mechanistic origin behind the microstructural changes.
Development of a bubble-based single cell picking system
Authors: Wang Ronghang , Liu Bingxin , Gong Jiahao , Zhang Jinlu , Gao Meng , Zhang Lunjia , Wang Xuelin , Chen Sen , Hong Jie , Gui Lin
Published: January 2022

In this work, we proposed a novel method to ‘pick’ single cell from a cluster of cells using bubbles as ‘fingers’. Particularly, the bubble was generated in the cell suspension solution via the pores in a porous membrane sandwiched between the solution channel and the gas channel. Controlling the pressure of the gas and the cell suspension could produce a bubble with certain size in the solution channel, and the bubble could capture a cell in its surface due to the interfacial tension between the cell suspension solution and the bubble, and then transfer the cell away. A simplified mechanical model was built to interpret the mechanism of the cell control. This method can be easily applied on multiple fields, including the single cell analysis, drug screening, cells sorting, and tumor biology, since it could separate a single cell from the cell cluster efficiently.