bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stability, optoelectronic and thermal properties of two-dimensional Janus α-Te2S
Authors: Singh Jaspreet , Jakhar Mukesh , Kumar Ashok 
Published: February 2022

Abstract
Motivated by recent progress in the two-dimensional (2D) materials of group VI elements and their experimental fabrication, we have investigated the stability, optoelectronic and thermal properties of Janus α-Te2S monolayer using first-principles calculations. The phonon dispersion and MD simulations confirm its dynamical and thermal stability. The moderate band gap (∼1.5 eV), ultrahigh carrier mobility (∼103 cm2 V−1 s−1), small exciton binding energy (0.26 eV), broad optical absorption range and charge carrier separation ability due to potential difference (ΔV = 1.07 eV) on two surfaces of Janus α-Te2S monolayer makes it a promising candidate for solar energy conversion. We propose various type-II heterostructures consisting of Janus α-Te2S and other transition metal dichalcogenides for solar cell applications. The calculated power conversion efficiencies of the proposed heterostructures, i.e. α-Te2S/T-PdS2, α-Te2S/BP and α-Te2S/H-MoS2 are ∼21%, ∼19% and 18%, respectively. Also, the ultralow value of lattice thermal conductivity (1.16 W m−1 K−1) of Janus α-Te2S makes it a promising material for the fabrication of next-generation thermal energy conversion devices.
A comparative study of electrical interfaces for tunable piezoelectric vibration energy harvesting
Authors: Morel Adrien , Brenes Alexis , Gibus David , Lefeuvre Elie , Gasnier Pierre , Pillonnet Gaël , Badel Adrien 
Published: February 2022

Abstract
The present work deals with tunable electrical interfaces able to enhance both the harvested power and bandwidth of piezoelectric vibration energy harvesters. The aim of this paper is to propose a general, normalized, and unified performance evaluation (with respect to the harvested power and bandwidth) of the various electrical strategies that can tune the harvester’s frequency response. By mean of a thorough analysis, we demonstrate how such interfaces influence the electromechanical generator response through an electrically-induced damping and an electrically-induced stiffness. The choice of the strategy determines these two electrical quantities, and thus the achievable frequency response of the system. Thereafter, we introduce a collection of graphical and analytical tools to compare and analyze single- and multi-tuning electrical strategies, including a qualitative performance evaluation of existing strategies. Finally, we establish a unified comparison of single- and multiple-tuning strategies which is supported by the definition and evaluation of a new optimization criterion. This comparison reveals which strategy performs best depending on the electromechanical coupling of the piezoelectric harvester and on the losses in the electrical interface. Furthermore, it quantifies the power and bandwidth gain brought by single- and multi-tuning strategies. Such quantitative criterion provides guidance for the choice of a harvesting strategy in any specific applicative case.
Stabilization and control of persistent current magnets using variable inductance
Authors: Brouwer Lucas , Shen Tengming , Norris Ryan , Hafalia Aurelio , Schlueter Ross , Wang Li , Ciston Jim , Ercius Peter , Ji Qing , Mankos Marian , Ophus Colin , Stibor Alexander , Schmid Andreas , Minor Andrew M , Denes Peter 
Published: February 2022

Abstract
Ultra-stable, tunable magnetic fields are desirable for a wide range of applications in medical imaging, electron microscopy, quantum science, and atomic physics. Superconducting magnets operated in persistent current mode, with device current flowing in a closed superconducting loop disconnected from a power source, are a common approach for applications with the most stringent requirements on temporal field stability. We present a method for active control of this persistent current by means of dynamic inductance change within the superconducting circuit. For a first realization of this general technique, we consider a variable superconducting inductor placed in series with the main magnet. The inductor acts as a dynamic flux storage device capable of transferring flux to or from the main magnet through inductance change. This allows for fine and fast adjustments of the persistent current without the use of thermal switches that limit the speed and accuracy of many present-day methods. With first experiments employing this technique, we demonstrate stabilization of a 1.95 T Nb–Ti round lens for electron microscopy against decay resulting from residual losses in the superconducting circuit, and more generally show flexibility for precise control over the magnitude and waveform of the persistent current.
Superconducting fault current limiter (SFCL) for a power electronic circuit: experiment and numerical modelling
Authors: Chen Xiaoyuan , Gou Huayu , Chen Yu , Jiang Shan , Zhang Mingshun , Pang Zhou , Shen Boyang 
Published: February 2022

Abstract
In this article, the superconducting fault current limiter (SFCL) explores its relatively new application: the power electronic circuit. The investigation of this compact-size SFCL involves both the experiments and numerical modelling. A bifilar-shape resistive-type SFCL was used in a DC-DC power conversion circuit, for the purpose of suppressing the overwhelming fault current by 3 different types of faults: the input fault, output fault, and switch fault. The numerical modelling of SFCL used an electromagnetic-thermal coupled finite-element method (FEM) model based on the
H
-formulation. For these 3 types of faults with the 100 ms fault duration, good agreement was found between the experiments and simulations. Both the experiment and modelling method were used to test the SFCL performance with different fault durations (50 ms vs 100 ms). For some severe fault conditions (e.g., higher fault current and longer fault duration) that experiments were difficult or unable to realise, the FEM modelling of SFCL was used to simulate the performance. Overall, the FEM modelling of SFCL can well match the SFCL experiment, and has the advantage of showing more information such as the current distribution and temperature. Both the SFCL experiments and numerical modelling offer new results and novel concepts of SFCL investigation, which can be helpful for the design of future SFCLs and the compact protection schemes for power electronic devices.
Random number generator via hexagonal boron nitride heterostructure
Authors: Hoseini Sani R , Behnia S 
Published: February 2022

Abstract
The nonlinearity is the heart of cryptographic methods which are based on the generation of pseudo-random numbers. In this study, the metal-insulator transition in hexagonal boron nitride (hBN) was investigated as a true random number generator. We have focused on the environmental-dependent behavior of hBN lattices, such as lattice size, impurity types, and applied external voltage on conductivity. The study was carried out based on random matrix theory, with spectral analysis of energy level spectrum and fractal dimension. The results indicate that by increasing the value of the electrical field, the hBN lattice behavior changes from Poisson (regular) to Wigner distribution (chaotic). The study of current-voltage variation has shown the periodic windows of quasi ohmic and the negative differential resistance. The produced electrical current ability as a random number has been examined through generating a dynamical S-box.
Prospects for dark matter signal discovery and model selection via timing information in a low-threshold experiment
Authors: Catena Riccardo , Zema Vanessa 
Published: February 2022

Abstract
In the recent years, many low-threshold dark matter (DM) direct detection experiments have reported the observation of unexplained excesses of events at low energies. Exemplary for these, the experiment CRESST has detected unidentified events below an energy of about 200 eV — a result hampering the detector performance in the search for GeV-scale DM. In this work, we test the impact of nuclear recoil timing information on the potential for DM signal discovery and model selection on a low-threshold experiment limited by the presence of an unidentified background resembling this population of low-energy events. Among the different targets explored by the CRESST collaboration, here we focus on Al2O3, as a sapphire detector was shown to reach an energy threshold as low as 19.7 eV [1]. We test the ability of a low-threshold experiment to discover a signal above a given background, or to reject the spin-independent interaction in favour of a magnetic dipole coupling in terms of p-values. We perform our p-value calculations: 1) taking timing information into account; and 2) assuming that the latter is not available. By comparing the two approaches, we find that under our assumptions timing information has a marginal impact on the potential for DM signal discovery, while provides more significant results for the selection between the two models considered. For the model parameters explored here, we find that the p-value for rejecting spin-independent interactions in favour of a magnetic dipole coupling is about 0.11 when the experimental exposure is 460 g×year and smaller (about 0.06) if timing information is available. The conclusion on the role of timing information remains qualitatively unchanged for exposures as large as 1 kg×5 year. At the same time, our results show that a 90% C.L. rejection of spin-independent interactions in favour of a magnetic dipole coupling is within reach of an upgrade of the CRESST experiment [2].
‘Pushing’ keys through quantum networks and the complexity of search of the true key
Authors: Molotkov S N 
Published: February 2022

Abstract
The question of the transfer of an external independent key through trusted nodes, between which the keys obtained during the quantum key distribution are located, is investigated. It is shown that when pushing external ɛ

K
-secret key through a chain of trusted nodes connecting separate segments with ɛ

i
-secret keys obtained by quantum key distribution, the final matched key between the extreme nodes of the network turns out to be

ε
=

ε
K

+

∑

i
=
1

N
s

ε
i

-secret (where i is the number of the network segment, N

s
is the number of network segments connecting the extreme nodes), provided that the external key is encrypted on the ɛ

i
–secret keys in the one-time pad mode. It is also shown that for any measurements of an eavesdropper providing him with additional information about the keys, the complexity of partial/complete search for an matched key is determined by the secrecy parameter ɛ.
Condensation driven by a quantum phase transition
Authors: Álvarez Miguel Ángel , Reslen Jose 
Published: February 2022

Abstract
The grand canonical thermodynamics of a bosonic system is studied in order to identify the footprint of its own high-density quantum phase transition. The phases displayed by the system at zero temperature establish recognizable patterns at finite temperature that emerged in the proximity of the boundary of the equilibrium diagram. The gapped phase underlines a state of collectivism/condensation at finite temperature in which particles coalesce into the ground state in spite of interacting attractively. The work establishes a framework that allows to study the phenomenon of condensation under the effect of attraction.
Non-destructive evaluation of coatings using terahertz reflection spectroscopy
Authors: Siv Sachin S D , Vijayan Vivek , Kini Rajeev N 
Published: February 2022

AbstractTerahertz time-domain spectroscopy (THz-TDS) provides a non-contact, non-destructive method for evaluating different materials and their properties. This short review discusses the commonly used numerical models for the non-destructive estimation of thickness, refractive index, surface and interface roughness of paints, thermal barrier coatings, and polymer coatings using THz-TDS in the reflection geometry. To demonstrate the applicability of these models, we used paint layers on metallic substrates and extracted different paraments by fitting the experimental THz-TDS data. We conclude by discussing further steps to improve the efficiency of the fitting procedure used to extract the layer parameters.
Covalent polymer functionalization of graphene/graphene oxide and its application as anticorrosion materials
Authors: Amin Ihsan , Batyrev Erdni , de Vooys Arnoud , van der Weijde Hans , Shiju N Raveendran 
Published: February 2022

Abstract
Research on grapheme-polymer composites as the promising ion barrier materials to tackle the corrosion issue is rapidly developing and attracts interests from both academia and industry. In this minireview, we highlight the covalent functionalization of graphene and its derivatives such as graphene oxide (GO) with polymer brushes, and their application in anticorrosion within the last 3 years. There are some recent excellent reviews published on single layer graphene and graphene-based polymer composites for anticorrosion. However, the covalent functionalization of graphene and GO with polymer brushes for application in anticorrosion has not been addressed in those reviews. In this review, we describe first the current state of the art of covalent functionalization of graphene/GO with polymer brushes. We then discuss the application of pristine graphene as anticorrosion material and its drawbacks which can be overcome by graphene-based polymer composites. Afterwards, we discuss in detail the recent progress and development of covalent polymer functionalized graphene/GO as anticorrosion coatings, reported within the last 3 years. Finally, as perspective, we will briefly summarize the work on composites of polymers with other two-dimensional (2D) materials as anticorrosion coatings. Herein, hexagonal boron nitride, the most studied 2D materials after graphene, and Ti3C2T
x
MXene which is the rising star of 2D transition metal carbide/nitride will be discussed.
Dry tribological properties of M50 bearing steel under different temperatures
Authors: Guo Hao , Duan Haitao , Wang Xingxing , Du Sanming , Zhang Yongzhen , Wang Pei 
Published: February 2022

Abstract
Reducing wear and clarifying relation mechanism are essential to improve the life of engine bearings, so we investigate the influence of ambient temperature on the friction characteristics of M50 steel self-matching pairs under dry friction conditions. As the ambient temperature increases from 30 °C to 500 °C, friction coefficient decreases sharply from 0.78 and tends to be stable around 0.4, while wear rate firstly decreases and then increases. High temperature (More than 300 °C) induces the serious oxidation and softening on the wear surface, causing the main wear mode from abrasive wear to adhesive wear. The oxides include mainly of Fe2O3 and Fe3O4, and minor MoO3 and Cr2O3, which are benefit for forming a continuous tribolayer on the wear surface, thereby improving the friction performance.
Metakaolin-red mud/carbon nanotubes geopolymer nanocomposite: mechanical properties and structural studies
Authors: Ahmadi Hamidreza , Khalaj Gholamreza , Najafi Abolhassan , Abbasi Saloumeh Mesgari , Safari Masumeh 
Published: February 2022

Abstract
In this research, the mechanical properties and structural studies of the geopolymer nanocomposite of metakaolin-red mud/carbon nanotubes were investigated. The geopolymer was designed by using metakaolin and red mud as aluminosilicate sources. Red mud replaced between 10 to 30% of the metakaolin. The mass ratio of the solid material and activator liquid was optimized in 1.5:1. Afterward, 1, 2, and 3 wt% multi-wall carbon nanotubes (MWCNTs) were dispersed in a polycarboxylate-based superplasticizer and were added to the geopolymer, which was mixed homogeneously. Geopolymer nanocomposites were characterized by XRD, FTIR, SEM, compressive and flexural strength measurements. The results indicated that the compressive and flexural strengths of the samples increased with curing time. The addition of red mud decreased the compressive and flexural strength of the geopolymer samples due to less reactivity and presence of a non-reactive impurity in red mud. By adding 2% MWCNTs, the compressive and flexural strengths increased to 37.05% and 36.06%, respectively, owing to the crack-bridging mechanism and filling of the cavities and porosity. FTIR spectra demonstrated the growth of the asymmetric stretching vibrations of T–O–Si (T: Si or Al) at approximately 995.85–1083.55 cm−1, confirming the realization of the geopolymerization process in the structure.
Implementation of apertures in a proton pencil-beam dose algorithm
Authors: Depauw N , Kooy H M , Daartz J , Bussière M , Batin E , Madden T , Williams M , Schueman J , Clasie B M 
Published: February 2022

Abstract
The use of field-specific apertures, routine in scattered or uniform-scanned proton fields, are still a necessity in pencil-beam scanned (PBS) fields to sharpen the penumbral edge at low energies and in high fraction dose application beyond that achievable with small spot size. We describe a model implemented in our clinical pencil-beam algorithm that models the insertion of a shaped aperture, including shapes adapted per energy layer such as may be achieved with a multi-leaf collimator. The model decomposes the spot transport into discrete steps. The first step transport a uniform intensity field of high-resolution sub-pencil-beams at the layer energy through the medium. This transport only considers primary scattering in both the patient and an optional range-shifter. The second step models the aperture areas and edge penumbral transition as a modulation of the uniform intensity. The third step convolves individual steps over the uniform-transported field including the aperture-modified intensities. We also introduce an efficient model based on a Clarkson sector integration for nuclear scattered halo protons. This avoids the explicit modeling of long range halo protons to the detriment of computational efficiency in calculation and optimization. We demonstrate that the aperture effect is primarily due to in-patient and shifter scattering with a small contribution from the apparent beam source position. The model provides insight into the primary physics contributions to the penumbra and the nuclear halo. The model allowed us to fully deploy our PBS capacity at our two-gantry center without which PBS treatments would have been inferior compared to scattered fields with apertures. Finally, Monte Carlo calculations have (nearly) replaced phenomenological pencil-beam models for collimated fields. Phenomenological models do, however, allow exposition of underlying clinical phenomena and closer connection to representative clinical observables.
Realizing high efficiency and large-area sterilization by a rotating plasma jet device
Authors: LI Hua , LI Minglei , ZHU Hongcheng , ZHANG Yuhan , DU Xiaoxia , CHEN Zhencheng , XIAO Wenxiang , LIU Kun 
Published: February 2022

Abstract
By tilting a plasma jet and rotating 360°, a large-area can be scanned and sterilized in a short time. Compared with the previous array device, this pipe has the significant advantages of high sterilization uniformity and low gas consumption. Firstly, a rotatable plasma jet device, which can control the swing and rotation of a jet pipe, is designed, and a corresponding theoretical model is established to guide the experiment. Secondly, with Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) as the target bacteria, the device achieves a short sterilization time of 158 s—the minimum sterilization flow of S. aureus and E. coli is 0.8 slm and 0.6 slm, respectively. The device is compared with an array plasma sterilization device in terms of sterilization speed and gas consumption. The results show that the device is not only better than an array plasma sterilization device with respect to scanning uniformity, but also far less than the array plasma sterilization device in gas consumption of 5 slm. Therefore, the device has great potential in applications involving efficient, large-area sterilization.
Microstructural observation and mechanical properties behavior of Al2O3/Al6061 nanocomposite fabricated by stir casting process
Authors: Awate Pankaj P. , Barve Shivprakash B. 
Published: February 2022

Abstract
Aluminum oxide (Al2O3) nanoparticles are capable of improving the material characteristics if reinforced to soft and low strength material. The major limitation in the utilization of Al alloy 6061 in medium to heavy stress applications such as automobile, defense, transportations, and aerospace is low hardness and strength. In order to overcome the deficiency of Al6061, nano-Al2O3 reinforced Al6061 matrix nanocomposite (AMNC) was successfully fabricated on machinated aluminum stir casting furnace. Al2O3 nanoparticles in 2,4,6 and 8 wt.% were reinforced in the Al6061 matrix and the effect on mechanical and microstructure behavior was investigated by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), hardness, and tensile testing methods. Higher magnification FESEM micrographs revealed that reinforcement of nano-Al2O3 leads to considerable grain refinement and uniform distribution with less porosity. The mechanical properties results showed enhancement in tensile strength (by 130%), hardness (by 156%), yield stress (by 360%) with reinforcement of nano-Al2O3 over the base alloy Al6061. It was observed that the nano size of Al2O3 particles, the quantity of reinforcement, and the stir casting process were effective factors on the microstructure and mechanical properties enhancement.
Factors Associated With Willingness to Receive a COVID-19 Vaccine Among 23,819 Adults Aged 50 Years or Older: An Analysis of the Canadian Longitudinal Study on Aging
Authors: Basta Nicole E , Sohel Nazmul , Sulis Giorgia , Wolfson Christina , Maimon Geva , Griffith Lauren E , Kirkland Susan , McMillan Jacqueline M , Thompson Mary , Raina Parminder ,   for the Canadian Longitudinal Study on Aging (CLSA) Research Team
Published: February 2022

Abstract
Identifying persons who are least willing to receive a coronavirus disease 2019 (COVID-19) vaccine is critical for increasing uptake via targeted outreach. We conducted a survey of 23,819 Canadian Longitudinal Study on Aging participants from September 29 to December 29, 2020, to assess factors associated with COVID-19 vaccination willingness and reasons for willingness or lack thereof. Among adults aged 50–96 years, 84.1% (95% confidence interval (CI): 83.7, 84.6) were very or somewhat willing to receive a COVID-19 vaccine; 15.9% (95% CI: 15.4, 16.3) were uncertain or very or somewhat unwilling. Based on logistic regression, those who were younger, female, had lower education and income, were non-White, and lived in a rural area were less willing to receive a COVID-19 vaccine. After controlling for these factors, recent receipt of influenza vaccine (adjusted odds ratio = 14.3, 95% CI: 12.5, 16.2) or planning to receive influenza vaccine (adjusted odds ratio = 10.5, 95% CI: 9.5, 11.6), as compared with no receipt or planning, was most strongly associated with COVID-19 vaccination willingness. Willingness was also associated with believing one had never been infected with severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) and experiencing negative pandemic consequences. Safety concerns were most common among those unwilling. Our comprehensive assessment of COVID-19 vaccination willingness among older adults in Canada, a prioritized group for vaccination due to their risk of severe COVID-19 outcomes, provides a road map for conducting outreach to increase uptake, which is urgently needed.