bluuebunny/crossref_metadata_2025_split huggingface dataset:
Horticultural training and education.
Authors: Morgan Lynette 
Published: January 2021

Abstract

The passing of knowledge from generation to generation has been the basis of human existence upon which civilisations have been built and expanded and a process that has accelerated with the use of modern technology. Horticulture is one of the oldest, if not the oldest, forms of knowledge gathering in the arts and sciences. It therefore follows that horticulture was one of the earliest civilising influences in mankind's history (Dixon, 2016). Horticultural skills were essential in early settlements during the dawn of agriculture, for food production and security and also for a wider range of plant materials that enhanced everyday life and contributed to industry. Horticultural knowledge and training has existed for some 10,000 to 20,000 years, with the skills of its practitioners demonstrated through advancing civilisations in both eastern and western countries (Aldous et al., 2014). The first processes in horticultural knowledge transfer were simply informal instruction of how to cultivate soil, grow and harvest crops, which were passed from parent to child and within the members of early societies. Historically gardening has been an integral part of a child's life and played a significant role in how and what they learnt (Relf and Lohr, 2003). These early instructional lessons allowed the passage of knowledge and practical cultivation skills and associated industries such as the manufacture of gardening tools, processing of crops and long-term storage methods.
A spectral method algorithm for numerical simulations of gravitational fields
Authors: Meringolo C , Servidio S , Veltri P 
Published: January 2021

Abstract
A numerical study of the Einstein field equations, based on the 3 + 1 foliation of the spacetime, is presented. A pseudo-spectral technique has been employed for simulations in vacuum, within two different formalisms, namely the Arnowitt–Deser–Misner (ADM) and the conformal Baumgarte–Shapiro–Shibata–Nakamura (BSSN) approach. The numerical code is based on the Fourier decomposition, accompanied by different filtering techniques. The role of the dealiasing, as well as the influence of the filter type, has been investigated. The algorithms have been stabilized via a novel procedure that controls self-consistently the regularity of the solutions. The accuracy of the model has been validated through standard testbeds, revealing that the filtered pseudo-spectral technique is among the most accurate approaches. Finally, the procedure has been stressed via black hole dynamics and a new strategy, based on hyperviscous dissipation that suppresses spurious boundary problems, has been proposed. The model represents a valid tool of investigation, particularly suitable for the inspection of small scale nonlinear phenomena in gravitational dynamics.
Laser interferometer in presence of scalar field on gravitational wave background
Authors: Ganjali Mohammad A , Sedaghatmanesh Zainab 
Published: January 2021

Abstract
Detection of gravitational waves opened new windows on fundamental physics and it would be natural to search how the role of extra dimensional effects can be traced to gravitational wave physics. In this article, we consider a toy model of five dimensional pure gravity theory compactified on a circle. The resulting four dimensional theory is a scalar-Maxwell theory which is minimally coupled with gravity. By finding the equations of motion for scalar, electric and magnetic fields, we would be able to find exact wave solutions of coupled equations which are zero mode solutions. We also perform perturbation in order to consider non-zero modes of electromagnetic fields. Having these solutions at hand, we study the recombination of scalar-affected electromagnetic waves in a typical Michelson interferometer. In particular, we obtain, up to first order, the change of amplitude of electromagnetic power due to presence of this scalar field which may reveal some signals of extra dimension.
Absolute ion density measurements in the afterglow of a radiofrequency atmospheric pressure plasma jet
Authors: Jiang Jingkai , Bruggeman Peter J 
Published: January 2021

Abstract
Atmospheric pressure plasma jets (APPJs) can enable large fluxes of reactive species impinging on treated substrates in many applications. The relative importance of ionic versus neutral reactive species fluxes produced by APPJs is to date mainly deduced from modeling due to the challenge of measuring absolute ion densities/fluxes. In this study, a calibration was performed to determine the absolute densities of cold ions in the afterglow region of an radiofrequency-driven APPJ in Ar + 1% O2 by molecular beam mass spectrometry. Positive ion densities were found to be about 3–4 orders of magnitudes lower than the densities of the dominant reactive neutral species (O, O2(a
1Δg), O3) in the afterglow region of the APPJ at a distance larger than 2 mm from the visible plasma plume. The results illustrate the ability of molecular beam mass spectrometry to enable a quantitative evaluation of both neutral and ionic species in many applications using APPJs.
Synaptic metaplasticity emulation in a freestanding oxide-based neuromorphic transistor with dual in-plane gates
Authors: Jiang Shanshan , He Yongli , Liu Rui , Zhang Chenxi , Shi Yi , Wan Qing 
Published: January 2021

Abstract
Synaptic plasticity is a basic characteristic of synapses and plays an important role in the computation, learning and memory of human brain. Metaplasticity is a higher-order form of synaptic plasticity, which regulates the ability of synapses to generate synaptic plasticity and has a great regulating effect on later learning, memory and coping behaviors. At present, there are rarely reports on the emulation of synaptic metaplasticity in synaptic transistor. In this article, flexible dual-gate indium-zinc-oxide neuromorphic devices on freestanding solid-state proton conducting chitosan electrolyte membrane are designed for metaplasticity emulation. The key synaptic plasticity functions including excitatory postsynaptic current, synaptic paired-pulse response and synaptic pulse train response can be effectively regulated by the priming pulse stimuli. Besides, configurable synaptic depression and synaptic potentiation effect can be realized in such device. These results can expand the potential applications of the multi-terminal electrolyte-gated oxide transistors for flexible dynamic neuromorphic platforms.
Modeling of vortex dynamics in HTSs with defects under the impact of pulsed magnetic field
Authors: Moroz A N , Kashurnikov V A , Rudnev I A , Maksimova A N 
Published: January 2021

Abstract
By means of the Monte Carlo method, a numerical study of the vortex system in a high-temperature superconductor under the impact of pulses of magnetic field has been conducted. Various shapes and amplitudes of pulses have been considered. Samples with random and regular distributions of three different numbers of defects have been compared from the viewpoint of efficiency of flux trapping. The low-temperature behavior of vortices and their penetration into samples have been shown to be independent of the pulse shape but strongly dependent of the type of pinning distribution. Saturating dependences of density of trapped magnetic flux on the pulse amplitude have been obtained. The samples with random pinning demonstrated higher efficiency of flux trapping at lower pulse amplitudes, and the samples with a triangular lattice of defects—at higher amplitudes. If the amplitude exceeded the saturation field of both samples, the trapped field was almost equal. The increasing number of defects has lead to an increase in trapped field within the considered range of concentrations.
A first-principles and machine learning combined method to investigate the interfacial friction between corrugated graphene
Authors: Liu Zugang , Zhao Xinpeng , Wang Heyuan , Ma Yuan , Gao Lei , Huang Haiyou , Yan Yu , Su Yanjing , Qiao Lijie 
Published: January 2021

Abstract
Simulating the frictional properties of complex interfaces is computational resource consuming. In this paper, we propose a density functional theory (DFT) calculation combined machine learning (ML) strategy to investigate the sliding potential energy corrugation between geometrical corrugated graphene (Gr) sheets. By the aid of few DFT calculations and geometrical descriptors Σr
−n
(n = 1, 2, 6, 12), the trained ML models can accurately predict the sliding potential evolutions of Gr/Pt and Gr/Re systems. To be specific, based on DFT calculations of sliding along [110] direction, the trained linear regression (LIN) models can properly give out the potential energy evolution along the [100] direction with deviation less than 5%. By the dataset of given distances (9.3 Å, 9.65 Å and 10 Å) between two Re monolayers in Gr/Re systems, LIN and Bayesian ridge regression (BR) models can quantitatively predict the potential energy evolution of unknown distances (9.2 Å, 9.4 Å, 9.5 Å and 9.6 Å). The predicted magnitudes of potential energy corrugations by BR model divert less than 3 meV Å−2 from DFT calculations. The prediction results for extrapolated distances (9.0 Å and 9.1 Å) deviate notably, but the extension of training dataset effectively improves the predictive ability of ML models, especially for the LIN model. Thus, the supposed strategy could become an effective method to investigate the frictional characteristics of complex interfaces.
Hybrid application of laser-focused atomic deposition and extreme ultraviolet interference lithography methods for manufacturing of self-traceable nanogratings
Authors: Liu Jie , Zhao Jun , Deng Xiao , Yang Shumin , Xue Chaofan , Wu Yanqing , Tai Renzhong , Hu Xiukun , Dai Gaoliang , Li Tongbao , Cheng Xinbin 
Published: January 2021

Abstract
A novel hybrid method that combines the laser-focused atomic deposition (LFAD) and extreme ultraviolet (EUV) interference lithography has been introduced. The Cr grating manufactured by LFAD has advantages of excellent uniformity, low line edge roughness and its pitch value determined directly by nature constants (i.e. self-traceable). To further enhance the density of the Cr grating, the EUV interference lithography with 13.4 nm wavelength was employed, which replicated the master Cr grating onto a Si wafer with its pitch reduced to half. In order to verify the performance of the gratings manufactured by this novel method, both mask grating (Cr grating) and replicated grating (silicon grating) were calibrated by the metrological large range scanning probe microscope (Met.LR-SPM) at Physikalisch-Technische Bundesanstalt (PTB). The calibrated results show that both gratings have excellent short-term and long-term uniformity: (i) the calibrated position deviation (i.e. nonlinearity) of the grating is below ±1 nm; (ii) the deviation of mean pitch values of 6 randomly selected measurement locations is below 0.003 nm. In addition, the mean pitch value of the Cr grating is calibrated as 212.781 ± 0.008 nm (k = 2). It well agrees with its theoretical value of 212.7787 ± 0.0049 nm, confirming the self-traceability of the manufactured grating by the LFAD. The mean pitch value of the Si grating is calibrated as 106.460 ± 0.012 nm (k = 2). It corresponds to the shrinking factor of 0.500 33 of the applied EUV interference lithographic technique. This factor is very close to its theoretical value of 0.5. The uniform, self-traceable gratings fabricated using this novel approach can be well applied as reference materials in calibrating, e.g. the magnification and uniformity of almost all kinds of high resolution microscopes for nanotechnology.
Quiescent regions below the X-point in ASDEX upgrade
Authors: Nem R D , Manz P , Juul Rasmussen J , Vianello N , Walkden N , Naulin V , Sieglin B , Herrmann A , Brida D 
Published: January 2021

Abstract
Probe measurements of plasma fluctuations in the divertor region of ASDEX Upgrade reveal the existence of two quiescent regions close to the separatrix: one on the low field side scrape-off layer and one on the high field side of the private flux region. The X-point manipulator at ASDEX Upgrade provides the unique possibility of obtaining continuous measurements of the ion-saturation current from the low field side scrape-off layer through the private flux region and into the high field side scrape-off layer.
Development of a Stark shift measurement technique using excited-state oxygen atoms to determine electron number density in shock heated O2/Ar above 10 000 K
Authors: Li Yang , Wang Shengkai , Strand Christopher L , Hanson Ronald K 
Published: January 2021

Abstract
We present measurements of electron number density, n
e, in partially ionized gases containing electronically excited atomic oxygen, at nominal translational temperatures between 10 100–11 200 K. The measurements were based on the Stark shift of the O(

P

3

5

) to O(

D

2
,
3
,
4

0

5

) transition at 926 nm. The current work scanned the laser across the transition and utilized the Stark shift of the absorbance for robust determination of n
e. The measurements were conducted in a shock-heated 1% O2/Ar mixture, with a measurement time resolution of 20 μs. A line-center shift of −0.06 cm−1 was observed within around 500 μs of the test time after the mixture was instantaneously heated to 11 200 K by the reflected shock wave, which corresponded to an electron number density increase from 0 to 2 ×  1021 m−3 due to collisional ionization. The measurement method and resulting data may be of interest in future studies of high-temperature air flows.
Etching of m-plane Zn(Mg)O epitaxial films and its impact on surface leakage currents
Authors: Hinkov Borislav , Hoang Hanh T , Hugues Maxime , Chauveau Jean-Michel , Strasser Gottfried 
Published: January 2021

Abstract
Zinc oxide is a novel material system for mid-infrared and THz optoelectronics. Especially its non-polar m-plane orientation is a promising candidate for the design of devices like quantum cascade lasers (QCLs) and detectors (QCDs). But for their realization novel fabrication schemes are needed. We present a new inductively coupled plasma reactive ion etching (ICP-RIE) process for etching of m-Zn(Mg)O heterostructures in a CH4-based chemistry. The process has been optimized for smooth vertical sidewalls together with high selectivity towards a SiN etch mask. This was achieved by combining the RIE etching with wet chemical etching in strongly diluted HCl. Similar to various types of semiconductor-based optoelectronic materials and devices (Sidor et al 2016 J. Electron. Mater.
45 4663–7; Ma et al 2016 Opt. Express
24 7823), including other wide-gap semiconductors like (In)GaN (Zhang et al 2015 Nanotechnology
26), we observe surface leakage currents in etched m-plane Zn(Mg)O structures. We show that they depend on the applied etching process and surface treatment techniques as well as the barrier composition in the Zn(Mg)O heterostructures. In addition, a treatment in hydrogen peroxide (H2O2) yields a significant surface leakage current suppression up to several orders of magnitude.
A novel magneto-mechanical metamaterial cell structure with large, reversible and rapid two-way shape alteration
Authors: Han Wenheng , Gao Wei , Wang Xingzhe 
Published: January 2021

Abstract
Smart mechanical metamaterials based on various types of stimuli-sensitive materials break through the limitations of traditional metamaterials and exhibit many attractive properties. The development of multi-functional mechanical metamaterials capable of multi-mode, reversible, large deformations and remote controllability remains a challenge. In this work, we designed and prepared several magneto-mechanical metamaterial unit cells based on magnetoactive soft materials using 3D printing technology. A novel cell structure of cuboctahedron was fabricated and examined deeply which was elongated or contracted along the central magnetic field direction under different external magnetic fields. Experiment and simulation results shown that the special metamaterial structure design enables the magneto-active unit cells to achieve super deformation characteristics that it does not originally possess. The rapid two-way large deformation of the cuboctahedron cell was achieved with a quite remarkable deformation up to 85%, and it could quickly return to the original shape of the cell when the magnetic field was removed. Besides of these capabilities, as an application example, we further demonstrated the multi-modal shape of shrinkage and elongation of the cell structure in a biomimetic blood vessel, to show the effectiveness of the prototype smart stent for particle transport in a remotely controllable manner. The developed magneto-mechanical metamaterial certainly can be extended to various functionalized application, such as soft robots, healthcare and flexible electronics.
Cement sensors with acoustic bandgaps using carbon nanotubes
Authors: Vemuganti S , Stormont J C , Pyrak-Nolte L J , Dewers T , Taha M M Reda 
Published: January 2021

Abstract
Cement is widely used in wellbores to stabilize the steel casing used in wellbore operations for oil and gas production, enhanced geothermal systems and carbon sequestration, and to limit fluid movement between sub-surface strata. Flaws such as microcracks in wellbore cement can lead to leakage along the wellbore compromising wellbore integrity. There is an increasing need for methods to monitor cement crack propagation in wellbore environments. In this study, we develop and report the first cementitious sensors capable of exhibiting high frequency acoustic bandgaps (ABGs) using carbon nanotubes (CNTs). Computational simulations of a sensor unit cell are used to design cement-multi walled carbon nanotubes (MWCNTs) sensors that show a wide bandgap. When the cement-MWCNTs sensors is embedded in cement specimens, bandgaps were measured experimentally under 300 kHz and under 600 kHz, consistent with the computationally predicted bandgaps in the range of 290–360 kHz, 410–460 kHz and 515–585 kHz. These bandgap features were absent in homogeneous cement specimens. X-ray tomographic reconstructions showed microscopic debonding at cement-MWCNTs sensor interface. Frequency response analysis of a three-dimensional computational model indicated a shift of frequency of minimum transmission due to the interface debonding, but no perturbation of bandgap response was observed. The cement-MWCNTs sensors developed in this study show the potential of a packed CNT inclusion material in cementitious matrix to create ABGs in a cement matrix.
Lamb wave based damage detection in metallic plates using multi-headed 1-dimensional convolutional neural network
Authors: Rai Akshay , Mitra Mira 
Published: January 2021

Abstract
Lamb wave based damage diagnosis holds potential for real-time structural health monitoring; however, analysing the Lamb wave response possess challenge due to its complex physics. Data-driven machine learning (ML) algorithms are often more effective in identifying the damage-related features from these complex responses. However, in analysing such complex responses the ML algorithms requires extensive data pre-processing and are often not suitable for real-time damage detection. This paper presents a deep learning multi-headed 1-dimensional convolutional neural network (1D-CNN) architecture capable to operate directly on raw discrete time-domain Lamb wave signals recorded from a thin metallic plate. The multi-headed configuration consisting of two parallel 1D-CNN layers is capable to learn higher order damage-related features and enhances robustness of overall classification performance. To train the adopted 1D-CNN algorithm a diverse database is also constructed consisting 216 numerically and 24 experimentally generated responses of a thin 1.6 mm Al-5052 plate structure. The diversification of training database is achieved by varying parameters like scanning length, scanning frequency and adding different levels of white noises to the captured responses. Later, the trained 1D-CNN architecture is tested against two separated unseen test-databases. The first test database consist of experimentally generated 12 samples with notch-like damage and 12 samples of pristine condition. The proposed 1D-CNN classifier generalizes well on the unseen samples and decisively predicts the outcome for 23 out of 24 samples of first test database. The second test database consists of 108 unseen FE simulated samples capturing additional damage scenarios. In the second test phase, the model has correctly predicted the condition of all the 108 samples.
Magneto-optical trapping using planar optics
Authors: McGehee William R , Zhu Wenqi , Barker Daniel S , Westly Daron , Yulaev Alexander , Klimov Nikolai , Agrawal Amit , Eckel Stephen , Aksyuk Vladimir , McClelland Jabez J 
Published: January 2021

Abstract
Laser-cooled atoms are a key technology for many calibration-free measurement platforms—including clocks, gyroscopes, and gravimeters—and are a promising system for quantum networking and quantum computing. The optics and vacuum hardware required to prepare these gases are often bulky and not amenable to large-volume manufacturing, limiting the practical realization of devices benefiting from the properties of cold atoms. Planar, lithographically produced optics including photonic integrated circuits, optical metasurfaces (MSs), and gratings offer a pathway to develop chip-scale, manufacturable devices utilizing cold atoms. As a demonstration of this technology, we have realized laser cooling of atomic Rb in a grating-type magneto-optical trap (MOT) using planar optics for beam launching, beam shaping, and polarization control. Efficient use of available light is accomplished using MS-enabled beam shaping, and the performance of the planar optics MOT is competitive with Gaussian-beam illuminated grating MOTs.
Driven dust vortex characteristics in plasma with external transverse and weak magnetic field
Authors: Laishram Modhuchandra 
Published: January 2021

Abstract
The two-dimensional hydrodynamic model for bounded dust flow dynamics in plasma is extended for analysis of driven vortex characteristics in presence of external transverse and weak magnetic field (B) in a planner setup and parametric regimes motivated by recent magnetized dusty plasma (MDP) experiments. This analysis has shown that shear in the B can produce a sheared internal field (E

a
) in between electrons and ions due to the E × B and ∇B ×
B
-drifts that cause rotation of dust cloud levitated in the plasma. The flow solution demonstrates that neutral pressure decides the dominance between the ions-drag and the E

a
-force. The shear ions-drag generates an anti-clockwise circular vortical structure, whereas the shear E

a
-force is very localized and gives rise to a clockwise D-shaped elliptical structure which turns into a meridional structure with decreasing B. Effect of the strength of B, shear mode numbers, and the sheath field are analyzed within the weak MDP regime, showing noticeable changes in the flow structure and its momentum. In the regime of high pressure and lower B, the E

a
-force becomes comparable or dominant over the ion drag and peculiar counter-rotating vortex pairs are developed in the domain. Further, when the B is flipped by 1800-degree, both the drivers act together and give rise to a single strong meridional structure, showing the importance of B-direction in MDP systems. Similar elliptical/meridional structures reported in several MDP experiments and relevant natural driven-dissipative flow systems are discussed.