bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of disequilibrium chemistry to spectral retrieval code ARCiS and application to 16 exoplanet transmission spectra
Authors: Kawashima Yui , Min Michiel
Published: November 2021

Context. The retrieval approach is currently a standard method for deriving atmospheric properties from observed spectra of exoplanets. However, the approach ignores disequilibrium chemistry in most current retrieval codes, which can lead to a misinterpretation of the metallicity or elemental abundance ratios of the atmosphere.

Aims. We have implemented the disequilibrium effect of vertical mixing or quenching for the major species in hydrogen and helium-dominated atmospheres, namely CH4, CO, H2O, NH3, N2, and CO2, for the spectral retrieval code ARCiS with a physical basis.

Methods. We used the chemical relaxation method and developed a module to compute the profiles of molecular abundances, taking the disequilibrium effect into account. Then, using ARCiS updated with this module, we performed retrievals of the observed transmission spectra of 16 exoplanets with sizes ranging from that of Jupiter to mini-Neptunes.

Results. We find indications of disequilibrium chemistry for HD 209458b (≥4.1σ) and WASP-39b (≥2.7σ). The retrieved spectrum of HD 209458b exhibits a strong NH3 absorption feature at 10.5 μm that is accessible by JWST owing to an enhanced abundance of NH3 due to the quenching effect. This feature is absent in the spectrum retrieved assuming equilibrium chemistry, which makes HD 209458b an ideal target for studying disequilibrium chemistry in exoplanet atmospheres. Moreover, for HAT-P-11b and GJ 436b, we obtain relatively different results compared to the retrieval with the equilibrium assumption, such as a 2.9σ difference for the C/O ratio. We have also examined the retrieved eddy diffusion coefficient but could not identify a trend over the equilibrium temperature, possibly due to the limits of the current observational precision.

Conclusions. We have demonstrated that the assumption of equilibrium chemistry can lead to a misinterpretation of the observed data, showing that spectral retrieval with a consideration of disequilibrium chemistry is essential in the era of JWST and Ariel.
Fundamental stellar parameters of benchmark stars from CHARA interferometry
Authors: Karovicova I. , White T. R. , Nordlander T. , Casagrande L. , Ireland M. , Huber D.
Published: November 2021

Context. Stellar models applied to large stellar surveys of the Milky Way need to be properly tested against a sample of stars with highly reliable fundamental stellar parameters. We have established a programme aiming to deliver such a sample of stars.

Aims. Here we present new fundamental stellar parameters of nine dwarf stars that will be used as benchmark stars for large stellar surveys. One of these stars is the solar-twin 18 Sco, which is also one of the Gaia-ESO benchmarks. The goal is to reach a precision of 1% in effective temperature (Teff). This precision is important for accurate determinations of the full set of fundamental parameters and abundances of stars observed by the surveys.

Methods. We observed HD 131156 (ξ Boo), HD 146233 (18 Sco), HD 152391, HD 173701, HD 185395 (θ Cyg), HD 186408 (16 Cyg A), HD 186427 (16 Cyg B), HD 190360, and HD 207978 (15 Peg) using the high angular resolution optical interferometric instrument PAVO at the CHARA Array. We derived limb-darkening corrections from 3D model atmospheres and determined Teff directly from the Stefan–Boltzmann relation, with an iterative procedure to interpolate over tables of bolometric corrections. Surface gravities were estimated from comparisons to Dartmouth stellar evolution model tracks. We collected spectroscopic observations from the ELODIE spectrograph and estimated metallicities ([Fe/H]) from a 1D non-local thermodynamic equilibrium (NLTE) abundance analysis of unblended lines of neutral and singly ionised iron.

Results. For eight of the nine stars we measure the Teff ⪅ 1%, and for one star better than 2%. We determined the median uncertainties in log g and [Fe/H] as 0.015 dex and 0.05 dex, respectively.

Conclusions. This study presents updated fundamental stellar parameters of nine dwarf stars that can be used as a new set of benchmarks. All the fundamental stellar parameters were based on consistently combining interferometric observations, 3D limb-darkening modelling, and spectroscopic analysis. The next paper in this series will extend our sample to giants in the metal-rich range.
Dispersive estimates for nonlinear Schrödinger equations with external potentials
Authors: Dietze Charlotte
Published: November 2021

We consider the long time dynamics of nonlinear Schrödinger equations with an external potential. More precisely, we look at Hartree type equations in three or higher dimensions with small initial data. We prove an optimal decay estimate, which is comparable to the decay of free solutions. Our proof relies on good control on a high Sobolev norm of the solution to estimate the terms in Duhamel’s formula.
A low-jitter timing generator based on completely on-chip self-measurement and calibration in a field programmable gate array
Authors: Qiu Wenjie , Xie Jianfeng , Liu Qinying , Han Xiaotao
Published: November 2021

This paper presents a high-stability and low-jitter Arbitrary Timing Generator (ATG) design based on the Xilinx Field Programmable Gate Array (FPGA) and its special integrated delay line. In recent years, FPGA-based or application specific integrated circuit-based delay lines have been used to achieve picosecond-level timing resolution. Devices with pure digital delay methods can only acquire triggers at the clock rising edges when triggered externally. Therefore, there is a large time irregularity caused by the uncertainty of the entry time of the trigger, which is difficult to compensate and leads to a large time jitter of outputs. We describe the design of an ATG that includes jitter self-measurement and calibration methods, which is available for both internal and external trigger modes. This structure is completely based on the FPGA’s own resources and has the advantages of being simple and flexible. Experimental results show a sub-nanosecond timing resolution of 78 ± 20 ps with a minimum of 120 ps and a time jitter of 160 ± 20 ps in the external trigger mode after compensation.
Orbital angular momentum spectrum of antenna vortex beam based on loop integration
Authors: Yang Guang , Zhang Lei , Li Weiwen , Liu Qing Huo
Published: November 2021

Due to the divergence characteristics of vortex microwaves, it is difficult to determine orbital angular momentum (OAM) orders through far fields, while the spiral spectrum analysis method based on the area integral of antenna near fields is complicated. In this paper, combined with near-field approximation processing, a spiral spectrum analysis method based on loop integration is proposed. According to the Laguerre–Gaussian vortex beam model, the key parameter estimation formulas suitable for low-order OAM microwave beams are derived, including the position of the reliable observation plane and the size of the annulus area. On this basis, the radius of the integral loop used for the spiral spectrum calculation is provided. Since only field data on the loop are collected in this method, the calculation amount is reduced and the analysis efficiency of the spiral spectrum is greatly improved. Due to the combination of near-field and far-field considerations, this method can fully reflect the spiral spectrum characteristics of antenna vortex waves.
Optical rectification by ratchet transport in an asymmetric grating
Authors: Moroshkin P. , Ochiai T. , Osgood R. , Xu J.
Published: November 2021

We report on electron ratchet transport’s manifestation in the optical rectification (OR) of an asymmetric grating. The photon-drag enabled effect is magnified by asymmetric photon scatterings and the induced optical nonlinearity associated with the surface plasmon polariton (SPP) via its near-field and gradient intensifications. The measured OR efficiency is increased multi-fold, over the prior art, which is attributable to its operating in a higher-order diffraction and nonlinearity regime and to a minimized coupling loss to a potential SPP mode at the lower interface.
The gate tunable 2D pn junction driven out-of-equilibrium
Authors: Chaves Ferney A. , Jiménez David
Published: November 2021

We have investigated the electrostatics and electronic transport of the gate tunable 2D pn junction by implementing a comprehensive physics-based simulator that self-consistently solves the 2D Poisson's equation coupled to the drift-diffusion current and continuity equations. The simulator considers the strong influence of the out-of-plane electric field through the gate dielectric and the presence of interface states. The impact of parameters such as gate capacitance, energy gap, and interface trap states density have been considered to model properties such as the depletion width, rectification factor, and depletion and diffusion capacitances. The present work opens the door to a wider exploration of potential advantages that gate tunable 2D pn junctions could bring in terms of figures of merit.
Band offsets of metal oxide contacts on TlBr radiation detectors
Authors: Voyce Olivia K. , Isaacs Mark A. , Harkness-Brennan Laura J. , Veal Tim D. , Judson Dan S. , Motakef Shariar , Datta Amlan
Published: November 2021

Metal oxides are investigated as an alternative to metal contacts on thallium bromide (TlBr) radiation detectors. X-ray photoelectron spectroscopy studies of SnO2/TlBr and ITO/TlBr devices indicate that a type-II staggered heterojunction forms between TlBr and metal oxides upon contacting. By using the Kraut method of valence band offset (VBO) determination, the VBOs of SnO2/TlBr and ITO/TlBr heterojunctions are determined to be 1.05±0.17 and 0.70±0.17 eV, respectively. The corresponding conduction band offsets are then found to be 0.13±0.17 and 0.45±0.17 eV, respectively. The I–V response of symmetric In/SnO2/TlBr and In/ITO/TlBr planar devices is almost Ohmic with a leakage current of less than 2.5 nA at 100 V.
Extended particle absorber for efficient modeling of intense laser–solid interactions
Authors: Miller Kyle G. , May Joshua , Fiuza Frederico , Mori Warren B.
Published: November 2021

An extended thermal particle boundary condition is devised to more efficiently and accurately model laser–plasma interactions in overdense plasmas. Particle-in-cell simulations of such interactions require many particles per cell, and a large region of background plasma is often necessary to correctly mimic a semi-infinite plasma and avoid electron refluxing from a truncated plasma. For long-pulse lasers of many picoseconds, such constraints can become prohibitively expensive. Here, an extended particle boundary condition (absorber) is designed that instantaneously stops and re-emits energetic particles streaming toward the simulation boundary over a defined region, allowing sufficient time and space for a suitably cool return current to develop in the background plasma. Tunable parameters of the absorber are explained, and simulations using the absorber with a 3-ps laser are shown to accurately reproduce those of a causally separated boundary while requiring only 20% the number of particles.
A review of many-body dissipative particle dynamics (MDPD): Theoretical models and its applications
Authors: Zhao Jiayi , Chen Shuo , Zhang Kaixuan , Liu Yang
Published: November 2021

Many-body dissipative particle dynamics (MDPD) is a novel coarse-grained numerical method that originated from dissipative particle dynamics. In the MDPD system, a density-dependent repulsive interaction and an attractive term are introduced into a conservative force, enabling the formation of vapor–liquid coexistence. In the last two decades, the MDPD is becoming a powerful tool to study various interfacial problems at mesoscale due to its Lagrangian and adaptive features. In the present paper, we review the developments in the theoretical models and applications for the MDPD. First, the MDPD theoretical backgrounds of single- and multi-component system are introduced. Then, the parameter analysis and mapping protocols in the MDPD are discussed. Furthermore, recent applications based on the MDPD, including droplet and microbubble dynamics, evolution of liquid bridges, capillary wetting, polymer solutions, and phase change, are revisited with some comments. Finally, we summarize several unsolved issues in the MDPD and outline its future developments.
Numerical studies on electron magnetohydrodynamics tearing mode instability
Authors: Guo Wenping , Wang Jiaqi , Liu Dongjian
Published: November 2021

The 2D electron-magnetohydrodynamics (EMHD) dominant tearing mode in an electron-skin-depth-scale current sheet (ECS) is further studied. The resistive diffusion is proved to be insignificant at the scale. Electron inertia leads to the expansion of the “inner region” as well as a wider saturation island and the invalidity of the boundary layer approximation. The unstable tearing mode index Δ′ thus decreases dramatically from that in classical asymptotic theory. As for nonlinear evaluation, the inverse spectral cascade and the flattening of the m = 0 anti-parallel asymptotic magnetic field will result in an m = 1 final island after nonlinear coupling in a long ECS. A rapid normal saturation transition is observed and only expected for a larger wave number due to the growth rate dependence on the wave number being a single humped function. A linear analysis of the EMHD tearing mode is also presented for the force-free equilibrium. With a strong guide field, it shows that the tearing mode can be suppressed by the shear flow. Nonlinear simulation results with specific parameters then showed that the dynamic structures in the current sheet are consistent with the observation in the Earth’s turbulent magnetosheath.
Unsteady aerodynamics of a model bristled wing in rapid acceleration motion
Authors: Wu Yu Kai , Liu Yan Peng , Sun Mao
Published: November 2021

Tiny insects with bristled wings perform the “rowing” motion: the wings accelerate rapidly from zero-velocity to certain reference velocity at 90° angle-of-attack, and the drag produced in this motion provides the weight-supporting force. A flat-plate wing will produce a large drag in such a motion, but it is unknown whether a bristled wing could do so. Here, we study this problem using numerical simulation and simple model wings. The acceleration is large: the wing translates only about half the wing chord length to reach the reference velocity. The following is shown. The bristled wing can produce a very large unsteady drag peak and large time-averaged drag as a flat-plate wing does; the time-averaged drag is about 2.5 times as large as the quasi-steady value. The force production mechanisms are different between the two wings: for the flat-plate wing, because of the large acceleration, the added-mass and the strong free vorticity in the flow produce a large pressure difference between the windward and leeward surfaces of the plate, resulting in large drag (surface frictional force has negligible contribution). Yet for the bristled wing, although the acceleration of the wing is large, a bristle needs to translate about 80 diameters to reach the reference velocity; thus, the effect of acceleration is very weak. Each bristle operates in a quasi-steady Stokes flow and the large drag of the bristled wing is due to the very large surface pressure and frictional forces on each bristle, generated by the strong viscous effect of the Stokes flow (the drag is equally contributed by the surface pressure and frictional forces).
Quantum dissipation with nonlinear environment couplings: Stochastic fields dressed dissipaton equation of motion approach
Authors: Chen Zi-Hao , Wang Yao , Xu Rui-Xue , Yan YiJing
Published: November 2021

Accurate and efficient simulation on quantum dissipation with nonlinear environment couplings remains a challenging task nowadays. In this work, we propose to incorporate the stochastic fields, which resolve just the nonlinear environment coupling terms, into the dissipaton-equation-of-motion (DEOM) construction. The stochastic fields are introduced via the Hubbard–Stratonovich transformation. After the transformation, the resulted stochastic-fields-dressed (SFD) total Hamiltonian contains only linear environment coupling terms. On the basis of that, SFD-DEOM can then be constructed. The resultant SFD-DEOM, together with the ensemble average over the stochastic fields, constitutes an exact and nonperturbative approach to quantum dissipation under nonlinear environment couplings. It is also of relatively high efficiency and stability due to the fact that only nonlinear environment coupling terms are dealt with stochastic fields, while linear couplings are still treated as the usual DEOM. Numerical performance and demonstrations are presented with a two-state model system.
Coupled Faxen relations for non-uniform slip Janus spheres
Authors: Premlata A. R. , Wei Hsien-Hung
Published: November 2021

A non-uniform surface slip can cause a symmetry breaking in the geometry of an otherwise homogeneous spherical particle to give rise to an anisotropic hydrodynamic resistance to the particle. Here, we develop a more general theoretical framework capable of decoding the surface-pattern-dependent hydrodynamic features for single heterogeneous spheres having arbitrary non-uniform slip length distributions in small variations, especially for those of weakly stick–slip or slip–slip Janus spheres in either the two-faced or striped type. Utilizing the Lorentz reciprocal theorem in conjunction with surface spherical harmonic expansion, we derive a new coupled set of Faxen formulas for the hydrodynamic force and torque on a non-uniform slip sphere by expressing impacts of slip anisotropy in terms of surface dipole and quadrupole without solving detailed flow fields. Our results reveal not only how various additional forces/torques arise from surface dipole and quadrupole, but also that it is the anti-symmetric dipole responsible for distinctive force-rotation/torque-translation coupling. These features are very distinct from those of no-slip or uniform-slip particles, possibly spurring new means to characterize or sort Janus particles in microfluidic experiments. In addition, the coupled Faxen relations with surface moment contributions reported here may infer potential changes in the collective nature of hydrodynamic interactions between non-uniform slip spheres. Furthermore, the present framework can also be readily applied to heterogeneous self-propelled squirmers whose swimming velocities are sensitive to slip anisotropy.
Measurement protocols dependent giant magnetocaloric effect in MnNiSi-based system
Authors: Ghosh Subrata , Samanta Saheli , Sinha Jayee , Mandal Kalyan
Published: November 2021

MnNiSi-based compounds exhibit giant isothermal magnetic entropy change (ΔSM) across their induced first-order coupled magnetostructural transition (MST) in the vicinity of room temperature, though in most of the cases, the use of Maxwell relation from a very frequently used but incorrect measurement protocol provides a nonphysical spike to the calculated ΔSM. Herein, to realize the accurate measurement protocol, we explore magnetocaloric properties of a (FeCoGa)x doped (MnNiSi)1−x compound with x = 0.165 rigorously. Several methods, including the estimation of ΔSM using Maxwell relation, Clausius-Clapeyron equation, and also from the calorimetry measurement, are discussed explicitly. The studied material is observed to show a MST at 265 K and a giant ΔSM as large as about −29.3 J kg−1 K−1 due to a magnetic field change of 5 T following the Maxwell equation during discontinuous cooling and field increasing mode, which enables the material as a promising candidate for magnetic refrigeration.
Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements
Authors: Hill J. Grant , Shaw Robert A.
Published: November 2021

New correlation consistent basis sets for the group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements have been developed specifically for use in explicitly correlated F12 calculations. This includes orbital basis sets for valence only (cc-pVnZ-PP-F12, n = D, T, Q) and outer core–valence (cc-pCVnZ-PP-F12) correlation, along with both of these augmented with additional high angular momentum diffuse functions. Matching auxiliary basis sets required for density fitting and resolution-of-the-identity approaches to conventional and F12 integrals have also been optimized. All of the basis sets are to be used in conjunction with small-core relativistic pseudopotentials [Figgen et al., Chem. Phys. 311, 227 (2005)]. The accuracy of the basis sets is determined through benchmark calculation at the explicitly correlated coupled-cluster level of theory for various properties of atoms and diatomic molecules. The convergence of the properties with respect to the basis set is dramatically improved compared to conventional coupled-cluster calculations, with cc-pVTZ-PP-F12 results close to conventional estimates of the complete basis set limit. The patterns of convergence are also greatly improved compared to those observed from the use of conventional correlation consistent basis sets in F12 calculations.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: November 2021

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials, which supersede earlier data or suggest new research applications.
No evidence for systematic voter fraud: A guide to statistical claims about the 2020 election
Authors: Eggers Andrew C. , Garro Haritz , Grimmer Justin
Published: November 2021

Significance

President Donald Trump claimed that the 2020 US presidential election was stolen; millions of Americans apparently believed him. We assess the most prominent statistical claims offered by Trump and his allies as evidence of election fraud, including claims about Dominion voting machines switching votes from Trump to Biden, suspiciously high turnout in Democratic strongholds, and the supposedly inexplicable failure of Biden to win “bellwether counties.” We use a combination of statistical reasoning and original data analysis to assess these claims. We hope our analysis contributes to public discussion about the integrity of the 2020 election and broader challenges of election security and election administration.
Autism-associated mutations in K
V
7 channels induce gating pore current
Authors: Gamal El-Din Tamer M. , Lantin Timothy , Tschumi Christopher W. , Juarez Barbara , Quinlan Meagan , Hayano Julia H. , Li Jin , Zweifel Larry S. , Catterall William A.
Published: November 2021

Significance

Autism spectrum disorder (ASD) adversely impacts >1% of children, causing social interaction deficits, repetitive behaviors, and communication disorders. Genetic analysis of ASD has advanced dramatically through genome sequencing, which has identified >500 genes with mutations in ASD. Mutations in the voltage sensor of the voltage-gated potassium (K
V
) channel K
V
7 are frequently associated with ASD. We discovered that these ASD mutations cause an ionic leak through the voltage sensor, termed gating pore current. When these mutations were inserted into the genome of mouse dopamine neurons, they caused a dramatic alteration in the ability of those neurons to fire action potentials in response to electrical stimulation. These changes would impair information processing in neurons, leading to broad changes in brain function.
Flexible cyclic-olefin with enhanced dipolar relaxation for harsh condition electrification
Authors: Wu Chao , Deshmukh Ajinkya A. , Yassin Omer , Zhou Jierui , Alamri Abdullah , Vellek John , Shukla Stuti , Sotzing Michael , Casalini Riccardo , Sotzing Gregory A. , Cao Yang
Published: November 2021

Significance

Flexible polymer dielectrics operable under not only electrical but also thermal extremes are desired for high-power-density and high-payload-efficiency electrification. Unfortunately, state-of-the-art high-temperature polymers exhibit largely reduced electrical energy storage performance, as traditionally their bandgaps are inversely correlated to the dielectric constants. Here, an all-organic polymer was reported with high dielectric constant originating from the enhanced dipolar relaxation, an uncompromised large bandgap of 4.84 eV, and a high glass transition temperature of 178 °C by locally decoupling the conjugation of polymer backbones. This rational strategic design uncovers a large unexplored space for the design of polymer dielectrics for multiple harsh conditions.
CHMP2B regulates TDP-43 phosphorylation and cytotoxicity independent of autophagy via CK1
Authors: Deng Xue , Sun Xing , Yue Wenkai , Duan Yongjia , Hu Rirong , Zhang Kai , Ni Jiangxia , Cui Jihong , Wang Qiangqiang , Chen Yelin , Li Ang , Fang Yanshan
Published: November 2021

The ESCRT protein CHMP2B and the RNA-binding protein TDP-43 are both associated with ALS and FTD. The pathogenicity of CHMP2B has mainly been considered a consequence of autophagy–endolysosomal dysfunction, whereas protein inclusions containing phosphorylated TDP-43 are a pathological hallmark of ALS and FTD. Intriguingly, TDP-43 pathology has not been associated with the FTD-causing CHMP2BIntron5 mutation. In this study, we identify CHMP2B as a modifier of TDP-43–mediated neurodegeneration in a Drosophila screen. Down-regulation of CHMP2B reduces TDP-43 phosphorylation and toxicity in flies and mammalian cells. Surprisingly, although CHMP2BIntron5 causes dramatic autophagy dysfunction, disturbance of autophagy does not alter TDP-43 phosphorylation levels. Instead, we find that inhibition of CK1, but not TTBK1/2 (all of which are kinases phosphorylating TDP-43), abolishes the modifying effect of CHMP2B on TDP-43 phosphorylation. Finally, we uncover that CHMP2B modulates CK1 protein levels by negatively regulating ubiquitination and the proteasome-mediated turnover of CK1. Together, our findings propose an autophagy-independent role and mechanism of CHMP2B in regulating CK1 abundance and TDP-43 phosphorylation.
The histone demethylase Lsd1 regulates multiple repressive gene programs during T cell development
Authors: Stamos Daniel B. , Clubb Lauren M. , Mitra Apratim , Chopp Laura B. , Nie Jia , Ding Yi , Das Arundhoti , Venkataganesh Harini , Lee Jan , El-Khoury Dalal , Li LiQi , Bhandoola Avinash , Bosselut Remy , Love Paul E.
Published: November 2021

Analysis of the transcriptional profiles of developing thymocytes has shown that T lineage commitment is associated with loss of stem cell and early progenitor gene signatures and the acquisition of T cell gene signatures. Less well understood are the epigenetic alterations that accompany or enable these transcriptional changes. Here, we show that the histone demethylase Lsd1 (Kdm1a) performs a key role in extinguishing stem/progenitor transcriptional programs in addition to key repressive gene programs during thymocyte maturation. Deletion of Lsd1 caused a block in late T cell development and resulted in overexpression of interferon response genes as well as genes regulated by the Gfi1, Bcl6, and, most prominently, Bcl11b transcriptional repressors in CD4+CD8+ thymocytes. Transcriptional overexpression in Lsd1-deficient thymocytes was not always associated with increased H3K4 trimethylation at gene promoters, indicating that Lsd1 indirectly affects the expression of many genes. Together, these results identify a critical function for Lsd1 in the epigenetic regulation of multiple repressive gene signatures during T cell development.
BiGONLight: light propagation with bilocal operators in numerical relativity
Authors: Grasso Michele , Villa Eleonora
Published: November 2021

BiGONLight, Bilocal Geodesic Operators framework for Numerical Light propagation, is a new tool for light propagation in numerical relativity. The package implements the bilocal geodesic operators formalism, a new framework for light propagation in general relativity. With BiGONLight it is possible to extract observables such as angular diameter distance, luminosity distance, magnification as well as new real-time observables like parallax and redshift drift within the same computation. As a test-bed for our code we consider two exact cosmological models, the ΛCDM and the inhomogeneous Szekeres model, and a simulated dust Universe. All our tests show an excellent agreement with known results.
Scalar gravitational wave signals from core collapse in massive scalar–tensor gravity with triple-scalar interactions
Authors: Huang Da , Geng Chao-Qiang , Kuan Hao-Jui
Published: November 2021

The spontaneous scalarization during the stellar core collapse in the massive scalar–tensor theories of gravity introduces extra polarizations (on top of the plus and cross modes) in gravitational waves, whose amplitudes are determined by several model parameters. Observations of such scalarization-induced gravitational waveforms therefore offer valuable probes into these theories of gravity. Considering a triple-scalar interactions in such theories, we find that the self-coupling effects suppress the magnitude of the scalarization and thus reduce the amplitude of the associated gravitational wave signals. In addition, the self-interacting effects in the gravitational waveform are shown to be negligible due to the dispersion throughout the astrophysically distant propagation. As a consequence, the gravitational waves observed on the Earth feature the characteristic inverse-chirp pattern. Although not with the on-going ground-based detectors, we illustrate that the scalarization-induced gravitational waves may be detectable at a signal-to-noise ratio level of

O

(

100

)

with future detectors, such as Einstein Telescope and Cosmic Explorer.
Computer-aided design of graphene and 2D materials synthesis via magnetic inductive heating of 11 transition metals
Authors: Dhaouadi Elyes , Hinkov Ivaylo , Pashova Katya , Challab Nabil , Roussigné Yves , Abderrabba Manef , Farhat Samir
Published: November 2021

We performed numerical simulations to determine the effect of the most influential operating parameters on the performance of a radio frequency (RF) induction-heating system in which RF magnetic fields inductively heat metal foils to grow graphene. The thermal efficiency of the system depends on the geometry as well as on the materials’ electrical conductivity and skin depth. The process is simulated under specific graphene and two-dimensional (2D) materials growth conditions using finite elements software in order to predict the transient temperature and magnetic field distribution during standard graphene and 2D materials growth conditions. The proposed model considers different coil Helmholtz-like geometries and 11 metal foils, including Ag, Au, Cu, Ni, Co, Pd, Pt, Rh, Ir, Mo, and W. In each case, an optimal window of process variables ensuring a temperature range of 1035 °C–1084 °C or 700 °C–750 °C suitable for graphene and MoS2 growth, respectively, was found. Temperature gradients calculated from the simulated profiles between the edge and the center of the substrate showed a thermal uniformity of less than ∼2% for coinage metals like Au, Ag, and Cu and up to 7% for Pd. Model validation was performed for graphene growth on copper. Due to its limited heat conductivity, good heating uniformity was obtained. As a consequence, full coverage of monolayer graphene on copper with few defects and a grain domain size of ∼2 µm was obtained. The substrate temperature reached ∼1035 °C from ambient after only ∼90 s, in excellent agreement with model predictions. This allows for improved process efficiency in terms of fast, localized, homogeneous, and precise heating with energy saving. Due to these advantages, inductive heating has great potential for large-scale and rapid manufacturing of graphene and 2D materials.
Toward nanotechnology-enabled face masks against SARS-CoV-2 and pandemic respiratory diseases
Authors: El-Atab Nazek , Mishra Rishabh B. , Hussain Muhammad M.
Published: November 2021

Wearing a face mask has become a necessity following the outbreak of the coronavirus (COVID-19) disease, where its effectiveness in containing the pandemic has been confirmed. Nevertheless, the pandemic has revealed major deficiencies in the ability to manufacture and ramp up worldwide production of efficient surgical-grade face masks. As a result, many researchers have focused their efforts on the development of low cost, smart and effective face covers. In this article, following a short introduction concerning face mask requirements, the different nanotechnology-enabled techniques for achieving better protection against the SARS-CoV-2 virus are reviewed, including the development of nanoporous and nanofibrous membranes in addition to triboelectric nanogenerators based masks, which can filter the virus using various mechanisms such as straining, electrostatic attraction and electrocution. The development of nanomaterials-based mask coatings to achieve virus repellent and sterilizing capabilities, including antiviral, hydrophobic and photothermal features are also discussed. Finally, the usability of nanotechnology-enabled face masks is discussed and compared with that of current commercial-grade N95 masks. To conclude, we highlight the challenges associated with the quick transfer of nanomaterials-enabled face masks and provide an overall outlook of the importance of nanotechnology in counteracting the COVID-19 and future pandemics.
Hexagonal arrays of plasmonic gold nanopyramids on flexible substrates for surface-enhanced Raman scattering
Authors: Simo P Christian , Laible Florian , Horneber Anke , Burkhardt Claus J , Fleischer Monika
Published: November 2021

Surface-enhanced Raman spectroscopy (SERS) with pyramidal gold nanostructures increases the signal of Raman active analytes, since hotspots form at the edges and tip of a nanopyramid under illumination. 2D hexagonal arrays of pyramidal nanostructures with a quadratic base are fabricated through cost-effective nanosphere lithography and transferred onto elastomeric polydimethylsiloxane. By making use of the {111} crystal plane of a silicon (100) wafer, an inverted pyramidal array is etched, which serves as the complementary negative for the gold nanostructures. Either a continuous gold thin-film with protruding pyramids or separate isolated nanopyramids are produced. Three basic fabrication strategies are presented. The SERS enhancement is verified by Raman mapping of 4-mercaptobenzoic acid (4-MBA) molecules. Fabrication on a flexible substrate paves the way for future applications on curved surfaces or in situ tunable resonances.
Smart arginine-equipped polycationic nanoparticles for p/CRISPR delivery into cells
Authors: Moradi Pardis , Hasanzadeh Akbar , Radmanesh Fatemeh , Rajai Daryasarei Saideh , Hosseini Elaheh Sadat , Kiani Jafar , Shahbazi Ali , Nourizadeh Helena , Eslami Maryam , Dorgalaleh Akbar , Sahlolbei Maryam , Hamblin Michael R , Karimi Mahdi
Published: November 2021

An efficient and safe delivery system for the transfection of CRISPR plasmid (p/CRISPR) into target cells can open new avenues for the treatment of various diseases. Herein, we design a novel nonvehicle by integrating an arginine-disulfide linker with low-molecular-weight PEI (PEI1.8k) for the delivery of p/CRISPR. These PEI1.8k-Arg nanoparticles facilitate the plasmid release and improve both membrane permeability and nuclear localization, thereby exhibiting higher transfection efficiency compared to native PEI1.8k in the delivery of nanocomplexes composed of PEI1.8k-Arg and p/CRISPR into conventional cells (HEK 293T). This nanovehicle is also able to transfect p/CRISPR in a wide variety of cells, including hard-to-transfect primary cells (HUVECs), cancer cells (HeLa), and neuronal cells (PC-12) with nearly 5–10 times higher efficiency compared to the polymeric gold standard transfection agent. Furthermore, the PEI1.8k-Arg nanoparticles can edit the GFP gene in the HEK 293T-GFP reporter cell line by delivering all possible forms of CRISPR/Cas9 system (e.g. plasmid encoding Cas9 and sgRNA targeting GFP, and Cas9/sgRNA ribonucleoproteins (RNPs) as well as Cas9 expression plasmid and in vitro-prepared sgRNA) into HEK 293T-GFP cells. The successful delivery of p/CRISPR into local brain tissue is also another remarkable capability of these nanoparticles. In view of all the exceptional benefits of this safe nanocarrier, it is expected to break new ground in the field of gene editing, particularly for therapeutic purposes.
Photo-exfoliation of MoS2 quantum dots from nanosheets: an in situ transmission electron microscopy study
Authors: Burns Kory , Bischoff Benjamin , Barr Christopher M , Hattar Khalid , Aitkaliyeva Assel
Published: November 2021

Fabrication of transition metal dichalcogenide quantum dots (QDs) is complex and requires submerging powders in binary solvents and constant tuning of wavelength and pulsed frequency of light to achieve a desired reaction. Instead of liquid state photoexfoliation, we utilize infrared laser irradiation of free-standing MoS2 flakes in transmission electron microscope (TEM) to achieve solid-state multi-level photoexfoliation of QDs. By investigating the steps involved in photochemical reaction between the surface of MoS2 and the laser beam, we gain insight into each step of the photoexfoliation mechanism and observe high yield production of QDs, led by an inhomogeneous crystalline size distribution. Additionally, by using a laser with a lower energy than the indirect optical transition of bulk MoS2, we conclude that the underlying phenomena behind the photoexfoliation is from multi-photon absorption achieved at high optical outputs from the laser source. These findings provide an environmentally friendly synthesis method to fabricate QDs for potential applications in biomedicine, optoelectronics, and fluorescence sensing.
Nonlinear evolution of Kinetic Alfvén Wave and the associated turbulence spectra in laser produced plasmas and laboratory simulation of astrophysical phenomena
Authors: Dewan Himani , Uma R , Sharma R P
Published: November 2021

This investigation presents the nonlinear interplay between pump wave (Kinetic Alfvén Wave (KAW)) and low-frequency ion acoustic wave (IAW) in the magnetized plasma. The model is developed by taking into account the ponderomotive nonlinearity associated due to the pump KAW. The coupled dimensionless equations (pump and IAW) are solved by adopting numerical simulation technique. The deduced results give the localization and filamentary structures of KAW, which eventually become chaotic with the evolution of time. The fundamental physics governing the dynamics of these two waves is influenced by the plasma beta (

β

) parameter; thereby affecting the nature of nonlinearity, dispersive properties and magnetic field amplification. The saturated spectra are analogous to that observed for many astrophysical scenarios for low (Chatterjee et al 2017 Nat. Commun.
8 15970) and high beta (White et al 2019 Nat. Commun.
10 1758; Tzeferacos et al 2017 Phys. Plasmas
24 041404) plasma. This theoretical model outlining the nonlinear interaction can be imperative in understanding the dynamics of magnetic field amplification in various astrophysical scenarios.
A speed measurement method for underwater robots using an artificial lateral line sensor
Authors: Zhang Zhuoliang , Zhou Chao , Cao Zhiqiang , Tan Min , Cheng Long , Deng Sai , Fan Junfeng
Published: November 2021

Underwater robot technology has made considerable progress in recent years. However, due to the harsh environment and noise in the flow field near the underwater robots, it is difficult to measure some basic parameters, including swimming speed. The traditional speed measurement methods for underwater robots have the disadvantages of being limited by the environment and bulky. In order to overcome these shortcomings, an artificial lateral line (ALL) sensor based on cantilever structure was developed in this paper. According to the deformation of cantilever beam under water impact, the swimming speed of underwater robots can be measured. In addition, an ‘end-to-end’ calibration algorithm was proposed to calibrate the ALL sensor in the noisy environment, avoiding the complicated noise modeling and filter design process. To reduce the risk of overfitting, a hybrid loss function based on physical model was adopted. Compared with the classical calibration method, our method can reduce the error by 47.8%. Our sensor achieved an average absolute error of 0.07897 m s−1, and can measure water speed up to 3 m s−1.
Linear gyrokinetic stability of a high
β
non-inductive spherical tokamak
Authors: Patel B.S. , Dickinson D. , Roach C.M. , Wilson H.R.
Published: November 2021

Spherical tokamaks (STs) have been shown to possess properties desirable for a fusion power plant such as achieving high plasma β and having increased vertical stability. To understand the confinement properties that might be expected in the conceptual design for a high β ST fusion reactor, a 1 GW ST plasma equilibrium was analysed using local linear gyrokinetics to determine the type of micro-instabilities that arise. Kinetic ballooning modes and micro-tearing modes are found to be the dominant instabilities. The parametric dependence of these linear modes was determined and, from the insights gained, the equilibrium was tuned to find a regime marginally stable to all micro-instabilities at θ
0 = 0.0. This work identifies the most important micro-instabilities expected to generate turbulent transport in high β STs. The impact of such modes must be faithfully captured in first-principles-based reduced models of anomalous transport that are needed for predictive simulations.
Building a turbulence-transport workflow incorporating uncertainty quantification for predicting core profiles in a tokamak plasma
Authors: Coster D.P. , Fischer R. , Hoenen O. , Lakhlili J. , Luk O.O. , Preuss R. , Scott B.D. , von Toussaint U. , the ASDEX Upgrade Team
Published: November 2021

The impact of micro-scale turbulence on the macro-scale plasma profiles in a tokamak is a multi-scale problem (both in space and time) that is treated in this paper by the coupling of turbulence simulations of multiple flux-tubes to a core transport code, together with an equilibrium code. Work on quantifying the uncertainty in the predicted profiles, together with a comparison to experiment is also presented.
Lithium wall conditioning techniques in ADITYA-U tokamak for impurity and fuel control
Authors: Jadeja K.A. , Ghosh J. , Yadava Nandini , Patel K.M. , Patel Kiran , Tanna R.L. , Manchanda R. , Chowdhuri M.B. , Raval J.V. , Nagora U.C. , Arambhadiya B.G. , Macwan Tanmay , Singh K. , Dolui S. , Shah Minsha , Patel Sharvil , Ramaiya N. , Shah Kajal , Shukla B.K. , Aich Suman , Kumar Rohit , Panchal V.K. , Kumar Manoj , Atrey P.K. , Pathak S.K. , Rajpal Rachana , Assudani Kumudni , Gopalakrishna M.V. , Kumawat Devilal , Makwana M.N. , Shah K.S. , Gupta Shivam , Gupta C.N. , Balakrishnan V. , Chattopadhyay P.K. , Kataria B.R.
Published: November 2021

In fusion devices, various techniques are employed for coating the plasma facing components (PFCs) including the vessel wall with low-Z material like lithium, boron, and silicon in order to enhance the plasma parameters and control. In ADITYA-Upgrade tokamak, different techniques of lithium wall conditioning are developed and implemented to obtain uniform and sustainable coating of Li on PFCs and the vessel wall. In this paper, two techniques used to generate Li from the source are reported. In one of the technique, a heated (fixed temperature of ∼120 °C) Li-rod is placed inside the hydrogen glow discharge cleaning (H-GDC) plasma and the sputtered Li by hydrogen (H) ions and atoms coats the wall and periphery. In the second technique, the Li is vapourized using a high-temperature Li-evaporator and released into the H-GDC plasma for uniform coating of Li on the PFCs and vessel. Significantly enhanced plasma parameters are obtained after Li coating by both techniques, with the evaporated Li performed better than the Li rod case. With the Li coating obtained with evaporated Li at 600 °C (550 mg Li) with H-GDC, the Li wall conditioning has been observed to be sustaining for in a larger number of plasma discharges in comparison to non-H-GDC assisted Li deposition. As the melting temperature of lithium hydride (LiH) is much higher (688.7 °C) than that of lithium (180.5 °C), this enhance the longer Li-coating lifetime relatively due to the formation of Li–H molecules on the vessel wall and PFCs. In ADITYA-U the carbon impurity and hydrogen recycling, due to relatively high surface area of graphite PFCs as well as their proximity to the plasma, limits the plasma performance and effective controls. Hence, H-GDC, H-GDC with Li-rod sputtering or Li evaporation, helium-GDC, argon–hydrogen mixtures-GDC in particular sequence are carried out to obtain better plasma discharges. The Li coating techniques and their effect on tokamak plasma discharges of ADITYA-U are discussed in this paper.
Combining GEDI and Sentinel-2 for wall-to-wall mapping of tall and short crops
Authors: Di Tommaso Stefania , Wang Sherrie , Lobell David B
Published: November 2021

High resolution crop type maps are an important tool for improving food security, and remote sensing is increasingly used to create such maps in regions that possess ground truth labels for model training. However, these labels are absent in many regions, and models trained on optical satellite features often exhibit low performance when transferred across geographies. Here we explore the use of NASA’s global ecosystem dynamics investigation (GEDI) spaceborne lidar instrument, combined with Sentinel-2 optical data, for crop type mapping. Using data from three major cropped regions (in China, France, and the United States) we first demonstrate that GEDI energy profiles can reliably distinguish maize, a crop typically above 2 m in height, from crops like rice and soybean that are shorter. We further show that these GEDI profiles provide much more invariant features across geographies compared to spectral and phenological features detected by passive optical sensors. GEDI is able to distinguish maize from other crops within each region with accuracies higher than 84%, and able to transfer across regions with accuracies higher than 82%, compared to 64% for transfer of optical features. Finally, we show that GEDI profiles can be used to generate training labels for models based on optical imagery from Sentinel-2, thereby enabling the creation of 10 m wall-to-wall maps of tall versus short crops in label-scarce regions. As maize is the second most widely-grown crop in the world and often the only tall crop grown within a landscape, we conclude that GEDI offers great promise for improving global crop type maps.
Applying Geospatial Technology in Estimating Agricultural Wastes Carrying Capacity in Grobogan Regency, Indonesia
Authors: Prasetyo A. , Heryanto B.
Published: November 2021

This study aimed to estimate using geospatial the feed carrying capacity of agricultural wastes, especially in Grobogan Regency, Central Java, Indonesia. The method that has been used in this study is the descriptive analysis which is sourced from secondary data from Grobogan Regency. Analysis of agricultural waste production includes rice straw, corn and soybeans converted into dry matter feed. Geospatial analysis using ArcGis 10.3 software to extract feed carrying capacity data in the form of maps. The result showed that dry matter agricultural wastes 405528.81 (tons/year), The capacity of beef cattle was 924606 (animal units) and the ability to add beef cattle was 791036 (animal units). The conclusion of the study that Grobogan Regency has to carrying capacity indexes were at safe levels.