bluuebunny/crossref_metadata_2025 huggingface dataset:
Planning flexible and smooth paths for lane‐changing manoeuvres of autonomous vehicles
Authors: Zhang Bo , Zhang Jianwei , Liu Yang , Guo Konghui , Ding Haitao
Published: January 2021

Lane‐changing manoeuvres are essential for daily driving tasks. Safety and comfort are the primary issues to be considered during the lane‐changing manoeuvres of autonomous vehicles. However, because the traffic environment is complicated and changeable, executing fixed lane‐changing manoeuvres cannot guarantee safety and comfort. Thus, it is important to find a flexible method that can plan and re‐plan a lane‐changing path according to the traffic environment in real time. But that remains smooth to ensure the vehicle occupants stay comfortable. Therefore, this paper proposes a method for planning a flexible and smooth lane‐changing path in real time. The proposed method uses the bi‐elementary paths to ensure comfort, and clothoid and arc curves are superimposed on the bi‐elementary paths to add re‐planning flexibility. Additionally, lookup tables and reasonable approximations are employed to quickly generate and evaluate lane‐changing paths. The results of the simulations demonstrate that the proposed method is able to plan and re‐plan a smooth lane‐changing path. Then, the results of vehicle experiments performed based on the embedded controller platform show that the proposed method guarantees real‐time performance, that the planned path is easy to follow, and that the planned paths make autonomous vehicle lane‐changing manoeuvres safe and comfortable.
Innovative mutual information‐based weighting scheme in stateless opportunistic networks
Authors: Lenando Halikul , Kurd Ali Aref Hassan , Chaoui Slim , Alrfaay Mohamad
Published: January 2021

Recently, opportunistic networks (OppNets) are considered as one of the most attractive developments of mobile ad hoc networks that have emerged, thanks to the development of intelligent devices. Owing to the harsh and dynamic topology of these networks, attaining high delivery ratio is a challenging issue. Hence, it is imperative to select which node's attribute must be adjusted to achieve a higher performance in such unpredictable networks. A mutual information‐based weighting scheme (MIWS) that exploits the entropy concept to assess the impact of the nodes' attributes on the network performance was proposed. The weighting procedure aims to figure out the correlative relations between different attributes and delivery ratio performance of the network. The high weight of certain attributes implies a correspondingly high impact in achieving efficient data forwarding. The proposed scheme is proofed conceptually and simulated using the Opportunistic Network Environment simulator. In contrast to previous studies conducted in the context of weight resolution, the proposed approach allows us to address this issue in real‐time stateless non‐social OppNets. Regardless of the deployed routing protocol, experiments show that adjusting nodes' attributes based on the proposed MIWS can improve the performance up to encouraging delivery ratios.
Atmosphere of Betelgeuse before and during the Great Dimming event revealed by tomography
Authors: Kravchenko K. , Jorissen A. , Van Eck S. , Merle T. , Chiavassa A. , Paladini C. , Freytag B. , Plez B. , Montargès M. , Van Winckel H.
Published: January 2021

Context. Despite being the best studied red supergiant star in our Galaxy, the physics behind the photometric variability and mass loss of Betelgeuse is poorly understood. Moreover, recently the star has experienced an unusual fading with its visual magnitude reaching a historical minimum. The nature of this event was investigated by several studies where mechanisms, such as episodic mass loss and the presence of dark spots in the photosphere, were invoked.

Aims. We aim to relate the atmospheric dynamics of Betelgeuse to its photometric variability, with the main focus on the dimming event.

Methods. We used the tomographic method which allowed us to probe different depths in the stellar atmosphere and to recover the corresponding disk-averaged velocity field. The method was applied to a series of high-resolution HERMES observations of Betelgeuse. Variations in the velocity field were then compared with photometric and spectroscopic variations.

Results. The tomographic method reveals that the succession of two shocks along our line-of-sight (in February 2018 and January 2019), the second one amplifying the effect of the first one, combined with underlying convection and/or outward motion present at this phase of the 400 d pulsation cycle, produced a rapid expansion of a portion of the atmosphere of Betelgeuse and an outflow between October 2019 and February 2020. This resulted in a sudden increase in molecular opacity in the cooler upper atmosphere of Betelgeuse and, thus, in the observed unusual decrease of the star’s brightness.
Systèmes de production locaux et gestion des ressources pastorales en Albanie. Entre stratégies d’acteurs et évolutions institutionnelles
Authors: Bombaj Florjan , Barjolle Dominique , Touzard Jean-Marc , Casabianca François , Gontard Simon
Published: January 2021

L’article analyse la dynamique des systèmes d’élevage d’un territoire montagneux albanais sous fortes contraintes socio-économiques, géographiques et historiques. L’objectif est de comprendre les processus qui ont conduit à la coexistence de systèmes d’élevage contrastés dans ce territoire et de montrer comment cette coexistence est liée à l’utilisation des ressources pastorales. Suite à la chute du régime communiste en 1991, la forte migration de la population vers les zones de plaine et la croissance de la demande pour les produits laitiers et carnés ont entraîné une augmentation de la production et de la taille des troupeaux dans ce territoire, avec une pression accrue sur les ressources pastorales. Les enquêtes réalisées dans cinq villages permettent de proposer une typologie des systèmes d’élevage, montrant la diversité des résultats économiques et des usages des ressources pastorales. Ces résultats questionnent l’évolution de l’élevage pastoral en Albanie dans le cadre d’une possible intégration de ce pays à l’Union européenne.
A review of the gas hydrate distribution offshore Chilean margin
Authors: Vargas-Cordero de la Cruz Ivan , Giustiniani Michela , Tinivella Umberta , Alessandrini Giulia
Published: January 2021

In last decades, the Chilean margin has been extensively investigated to better characterize the complex geological setting through the acquisition of geophysical data and, in particular, seismic lines. The analysis of seismic lines allowed identifying the occurrence of gas hydrates and free gas in many places along the margin. Clearly, the gas hydrate reservoir could be a strategic energy reserve for Chile, but, on the other hand, the dissociated of gas hydrate due to climate change could be an issue to face. Moreover, this region is characterized by large and mega-scale earthquakes that may contribute to gas hydrate dissociation and consequent submarine slides triggering. In this context, Chilean margin should be considered a natural laboratory to study the hydrate system evolution.
The modern interpretation of the high-flow gas wells study results
Authors: Roy Nick , Usenko Irina , Аkulshyn Oleksandr , Limar Igor
Published: January 2021

Based on the analysis of the currently existing methods of interpreting the results of research into gas-saturated and gas-condensate formations in the case of stationary or non-stationary filtration, the direction of solving this problem is indicated specifically for high-flow wells using new calculation method. Since the method has not existed in the traditional way until now, the new one is based on an original and unconventional approach to the initial data. And the results of its application are several times higher than the results of the traditional approach to the study of gas wells with a stationary inflow. That is, the method directly affects the quantity and quality of information obtained in the study on the gas-hydrodynamic characteristics of the studied high-flow gas wells. It also made it possible to develop a new technological approach to well testing, which at present should be considered rational, optimal and most modern. This method and the results that it allows to obtain are given in this publication. All this taken together makes it possible to approve a successful solution to the complex and still unsolved problem of the technological and methodological plan for the study of high-flow gas wells.
Specific features of drilling mode with extendable working elements
Authors: Ratov Boranbay , Fedorov Boris , Sudakov Andrii , Taibergenova Indira , Kozbakarova Saltanat
Published: January 2021

The work is devoted to the calculation of the main technological parameters of a bit of a new patented design, the essence of which is to replace worn out working elements (carbide cutters or diamond-containing matrices) during drilling with a new, not blunt tool right at the bottom of the well. The need to correct the calculation method is associated with the design feature of the new crown, which consists in the fact that when using it, an annular bottom of a larger width is formed compared to serial crowns of the same outer diameter. Therefore, the known formulas for carbide and diamond drilling have been supplemented with appropriate correction values so that the ROPs when using new and serial bits are the same during full development. So, when using carbide cutters as rock-cutting elements, a correction factor is introduced that increases the number of main cutters in the crown sectors of the first and second stages. In diamond cutting, it is necessary to increase the maximum speed of the tool, taking into account the mining technical conditions of penetration. Refined formulas for calculating the parameters of the drilling mode allow preserving the advantages of bits with extendable working elements and increasing the drilling speed by 1.7-1.8 times compared to existing serial bits.
Gas hydrates technologies in the joint concept of geoenergy usage
Authors: Dychkovskyi Roman , Tabachenko Mykola , Zhadiaieva Ksenia , Dyczko Artur , Cabana Edgar
Published: January 2021

The paper represents the analysis, which has helped to establish the usage of gas hydrate technologies in the methane conversion. This gas could be obtained in different ways. Possibilities and sources for the gas obtaining have been demonstrated. Use of other environmentally friendly sources to support operation in such systems in terms of joint energy complex has been considered. The necessary kinetic connections to provide operational sustainability of all the constituents have been given. The approach helps evaluate quantitatively the priority of its physicochemical transformations to obtain gas hydrates artificially. It is possible to transport methane at considerable distances when it is solidified. Actually, in this case there is no necessity to build costly compressor stations and pipelines for its transportation to consumers. The approach is extremely important for mining regions as it helps prolong the operating period and working out of the abandoned and off-balance coal reserves. In this case, it is proposed to apply special gasification technologies tending to maximum methane recovery. The proposed solutions give the possibility to define the trends of our further research. They will be highlighted in the following authors’ studies.
Das Asylbewerberleistungsgesetz in der medizinischen Fachliteratur: Ein Scoping Review
Authors: Führer Amand , König Maximiliane , Kluth Winfried
Published: January 2021

Hintergrund Die medizinische Versorgung von Asylsuchenden wird durch rechtliche Regelungen – v. a. das Asylbewerberleistungsgesetz (AsylbLG) – erschwert, die die Abrechnung von Leistungen für diese Patientengruppe betreffen. Ärztinnen und Ärzte sollten daher mit dem AsylbLG vertraut sein, um Versorgungsdefizite in der Behandlung dieser vulnerablen Patientengruppe zu vermeiden. Diese Arbeit untersucht, wie das AsylbLG in der deutschsprachigen medizinischen Literatur beschrieben wird und inwiefern diese Darstellungen die aus der Literatur bekannten Informationsbedarfe der Ärzteschaft treffen.

Methoden Scoping Review der zwischen 01.01.2015 und 14.04.2020 veröffentlichten deutschsprachigen Literatur zur medizinischen Versorgung von Asylsuchenden in Deutschland.

Ergebnisse In die Analyse wurden 55 Artikel eingeschlossen. Der Großteil der Artikel (80%, n=44) verwies auf das AsylbLG als wichtigen Kontextfaktor medizinischer Versorgung. Während die Gruppe der Leistungsberechtigten und der Zeitraum des Leistungsbezugs überwiegend korrekt beschrieben wurden, war die Darstellung des im AsylbLG vorgesehenen Leistungsumfangs nur bei 16% (n=9) der Artikel korrekt und vollständig. Auf den administrativen Kontext des Gesetzes und seines Regelungsgegenstandes wurde nur selten eingegangen. Zudem wurde das AsylbLG häufig (23%, n=10) – unzutreffender Weise – als normativer Maßstab für ärztliches Handeln präsentiert.

Schlussfolgerungen Die Darstellung des AsylbLG in der Fachliteratur scheint häufig nicht geeignet, Ärztinnen und Ärzten bei den praktischen Problemen in der Versorgung von Asylsuchenden zu helfen. Dafür wäre eine differenziertere Darstellung nötig, die auch die juristische Literatur zum Thema rezipiert.
Analyse des Risikoprofils stationärer Epistaxis-Patienten
Authors: Ketterer Manuel Christoph , Reuter Thea Charlott , Knopf Andreas , Hildenbrand Tanja
Published: January 2021

Hintergrund Epistaxis ist eine weit verbreitete Erkrankung, die sowohl dem niedergelassenen Allgemeinmediziner und HNO-Arzt als auch dem in der Klinik tätigen Kollegen häufig begegnet. Ziel dieser Arbeit ist es, Patienten, die an der HNO-Universitätsklinik Freiburg zwischen 2014 und 2018 stationär wegen Epistaxis behandelt wurden, hinsichtlich Ätiologie, Risikofaktoren und therapeutischer Maßnahmen zu untersuchen.

Methoden Im Rahmen der retrospektiven Studie wurden die Daten der Patienten mit Epistaxis hinsichtlich Alter, Vorerkrankungen, Dauermedikation, Lokalisation der Blutung, radiologischer Diagnostik und Therapie analysiert. Risikofaktoren für eine längere stationäre Verweildauer und eine Wiederaufnahme wurden bestimmt.

Ergebnisse Die mediane stationäre Aufenthaltsdauer betrug 3,5 Tage. 55 % der Patienten litten unter einer posterioren Epistaxis. 72,3 % der Patienten waren zum Zeitpunkt der stationären Aufnahme antikoaguliert. Häufigste Komorbiditäten waren arterielle Hypertonie (66 %) und Arrhythmie bei Vorhofflimmern (36,1 %). 63,5 % der Fälle wurden mit einer Nasentamponade versorgt. 97 Patienten (14,6 %) mussten operativ versorgt werden. Eine Operation, Transfusion, die posteriore Epistaxis und eine vorhandene Antikoagulation erwiesen sich als Risikofaktoren für eine längere stationäre Verweildauer. Eine vorbekannte Hypertonie, die posteriore Blutung und einfache Antikoagulation erhöhten das Risiko für eine stationäre Wiederaufnahme.

Diskussion Die Bestimmung und Berücksichtigung von Risikofaktoren erlauben die Identifikation von Patienten mit einem höheren Risiko für einen längeren stationären Aufenthalt und eine stationäre Wiederaufnahme. Ein adäquates Management, abgestimmt auf das Risikoprofil, könnte helfen, die Morbidität auf Seiten der Patienten zu verringern.
Construction of Spiro[3-azabicyclo[3.1.0]hexanes] via 1,3-Dipolar Cycloaddition of 1,2-Diphenylcyclopropenes to Ninhydrin-Derived Azomethine Ylides
Authors: Boitsov Vitali M. , Stepakov Alexander V. , Wang Siqi , Filatov Alexander S. , Lozovskiy Stanislav V. , Shmakov Stanislav V. , Khoroshilova Olesya V. , Larina Anna G. , Selivanov Stanislav I.
Published: January 2021

The multi-component 1,3-dipolar cycloaddition of ninhydrin, α-amino acids (or peptides), and cyclopropenes for the synthesis of spirocyclic heterocycles containing both 3-azabicyclo[3.1.0]hexane and 2H-indene-1,3-dione motifs has been developed. This method provides easy access to 3-azabicyclo[3.1.0]hexane-2,2′-indenes with complete stereoselectivity and a high degree of atom economy under mild reaction conditions. A broad range of cyclopropenes and α-amino acids have been found to be compatible with the present protocol, which offers an opportunity to create a new library of biologically significant scaffold (3-azabicyclo[3.1.0]hexane). In addition, the сomprehensive study of mechanism of azomethine ylide formation from ninhydrin and sarcosine was performed by means of M11 density functional theory (DFT) calculations. It has been revealed that experimentally observed 1-methylspiro[aziridine-2,2′-indene]-1′,3′-dione is a kinetically controlled product of this reaction and appears to act as a 1,3-dipole precursor. This theoretical study also shed light on the main transformations of the azomethine ylide derived from ninhydrin and sarcosine such as a 1,3-dipolar cycloaddition to cyclopropene dipolarophiles, a dimerization reaction and a (1+5) electrocyclization reaction. The antitumor activity of some synthesized compounds against cervical carcinoma (HeLa­) cell line was evaluated in vitro by MTS-assay.
Efficient Route for the Synthesis of Diverse Heteroannelated 5-Cyanopyridines
Authors: Volochnyuk Dmitriy M. , Ryabukhin Sergey V. , Mityuk Andrey P. , Hrebonkin Andrii , Lebed Pavlo S. , Grabchuk Galyna P.
Published: January 2021

The new efficient, convenient protocol for the synthesis of heteroannelated 3-cyanopyridines and pyrimidines starting from diverse aminoheterocycles and 3,3-dimethoxy-2-formylpropionitrile sodium salt was elaborated. The advantages and improvements of the procedure compared to previously known methods are shown. The scope and limitations of the method are determined. The impact of the structural features on regioselectivity are discussed. The preparativeness, scalability, and application scope of the elaborated protocol are demonstrated by the synthesis of five heteroannelated 3-cyanopyridines in quantities up to 100 grams.
Syntheses of Spiro(2-oxopyrrolidinyl)-5,4′-pyrazolones via Organocatalyzed Michael/Ammonolysis Cascade Reaction of 4-Aminopyrazolones and α,β-Unsaturated Acyl Phosphates
Authors: Chen Lin , Li You-Fen , Chen Zheng-Jun , Jiao Wen-Ya , Chen Zhi-Jiao
Published: January 2021

The efficient organocatalyzed Michael/ammonolysis cascade reaction of N-protected 4-aminopyrazolones and α,β-unsaturated acyl phosphates has been developed. This tactic gives rise to architecturally multifarious spiro(2-oxopyrrolidinyl)-5,4′-pyrazolones in good productiveness (up to 88% yield) and with moderate to good diastereoselectivities (up to 20:1 dr). These novel hybrid heterocycles would be promising candidates for drug-discovery programs and chemical biology.
Self-generating quality control
Authors: Hillman Tomos , Lizzi Vincent
Published: January 2021

This paper demonstrates how quality control infrastructure can be generated from a single requirements document. Taken from a recent project that is now being used in production at a large journal publisher, it discusses some of the challenges faced and techniques used when generating Schematron, XSpec tests, XML grammar checks, and documentation.

The project set out to implement quality control requirements for journal articles using Schematron. In pursuing this objective, the project also created quality control infrastructure for Schematron itself that streamlines the process for incorporating iterative changes to requirements.

The techniques used in this project and described in this paper may be generally applicable in other projects.
Characterisation on impact-toughness in Al-bearing hot-rolled TRIP steel produced through dynamic-partitioning
Authors: Wang Xiao-hui , Kang Jian , Li Yun-jie , Yuan Guo , Misra Raja Devesh Kumar , Wang Guo-dong
Published: January 2021

In this study, an energy-efficient processing route involving hot rolling and on-line heat treatment was proposed, which was applied to Al-containing hot-rolled TRIP steel. The experiments were carried out involving hot rolling and on-line heat treatment, where the samples were subjected to different processing routes. The results showed that the cooling temperature determined the microstructural type of experimental steels, while the cooling pattern determined the decomposition state of retained austenite. The introduction of polygonal ferrite in martensitic matrix, and decomposition of retained austenite in ferritic and bainitic matrix were harmful to impact toughness. The fracture mode in ferritic matrix through air cooling was ductile fracture containing dimples and the fracture morphology reflected the best impact toughness of 134 J in selected steels.
Derivation of Jacobian formula with Dirac delta function
Authors: Kim Dohyun , Ee June-Haak , Yu Chaehyun , Lee Jungil
Published: January 2021

We demonstrate how to make the coordinate transformation or change of variables from Cartesian coordinates to curvilinear coordinates by making use of a convolution of a function with Dirac delta functions whose arguments are determined by the transformation functions between the two coordinate systems. By integrating out an original coordinate with a Dirac delta function, we replace the original coordinate with a new coordinate in a systematic way. A recursive use of Dirac delta functions allows the coordinate transformation successively. After replacing every original coordinate into a new curvilinear coordinate, we find that the resultant Jacobian of the corresponding coordinate transformation is automatically obtained in a completely algebraic way. In order to provide insights on this method, we present a few examples of evaluating the Jacobian explicitly without resort to the known general formula.
Rotational collisions via inductive coupling
Authors: D’Anna Michele , Fuchs Hans U
Published: January 2021

We analyze an example of a totally inelastic interaction between two spinning objects from a didactic perspective. We first describe an interpretative model highlighting why a part of the initial rotational energy needs to be dissipated; this point can be visualized in a diagram of capacitive characteristic curves. Subsequently, we propose and discuss a concrete novel experiment, in which an inductive coupling between two spinning objects is realized. A detailed energy analysis and an introduction to dynamical modeling complete the proposed didactical approach.
Large enhancement of magnetic damping in the presence of domain walls in spin valves
Authors: Su Jian , He Wei , Li Gang , Bai He , Zhu Z Z , Zhang Ying , Cheng Z H , Cai J W
Published: January 2021

Magnetic damping of the free layer of CoFeB in the spin valve IrMn/CoFe/Cu/CoFeB with large exchange bias has been characterized by frequency-swept ferromagnetic resonance under a series of fixed magnetic fields. The damping constant shows little difference between the parallel and antiparallel magnetization configurations, consistent with the theoretical prediction. Remarkably, in the intermediate states of the pinned CoFe layer under reversal, the effective damping constant of the CoFeB layer is significantly enhanced from 0.0119 up to 0.0292. This enhancement, exceeding the effect of the pumped spin current appreciably, is mainly due to the inhomogeneous broadening and/or two-magnon scattering caused by the stray field emerging from the domain walls (DW) of the pinned CoFe layer when its magnetization is partially reversed. Meanwhile, a resonance frequency shift is also observed in the presence of DW. Our result confirms the strong influence of the pinned layer DW on the magnetic damping in spin valves, which should be properly excluded while dealing with the nonlocal spin-transport-induced damping in heterostructures.
Ligand dependent magnetism of the

Jeff

= 3/2 Mott insulator Cs2
MX
6 (M = Ta, Nb, X = Br, Cl)
Authors: Ishikawa Hajime , Yajima Takeshi , Matsuo Akira , Kindo Koichi
Published: January 2021

Magnetic and structural properties of double perovskite type bromides Cs2
MBr6 (M = Ta, Nb), where Ta4+ (5d
1) and Nb4+ (4d
1) ions form the face centered cubic lattice, are investigated and compared with chlorides Cs2
MCl6. Cs2TaBr6 exhibits the effective magnetic moment of 0.24 μ
B, which is much smaller than the spin only value of a d
1 ion, 1.73 μ
B, and comparable to 0.25 μ
B in Cs2TaCl6. On the other hand, the effective magnetic moment of Cs2NbBr6 is 0.7 μ
B and is substantially smaller than 1.0 μ
B in Cs2NbCl6. On cooling, successive structural and magnetic phase transitions accompanying the release of electronic entropy approximately Rln 4 in total as expected for the J
eff = 3/2 state are observed. The type of the ligand changes the temperature dependence of magnetic susceptibility at low temperature as well as its magnitude. The role of the ligands on the magnetism of J
eff = 3/2 Mott insulators are discussed in the light of metal–ligand hybridization and the electron–lattice coupling.
Q = 0 order in quantum kagome Heisenberg antiferromagnet
Authors: Mondal Kallol , Kadolkar Charudatt
Published: January 2021

We have studied the nearest neighbor Heisenberg model with added Dzyaloshinskii–Moriya interaction using Schwinger boson mean-field theory considering the in-plane component as well as out-of-plane component. Motivated by the experimental result of vesignieite that the ground state is in a Q = 0 long-range order state, we first looked at the classical ground state of the model and considered the mean-field ansatz which mimics the classical ground state in the large S limit. We have obtained the ground-state phase diagram of this model and calculated properties of different phases. We have also studied the above model numerically using exact diagonalization up to a system size N = 30. We have compared the obtained results from these two approaches. Our results are in agreement with the experimental result of the vesignieite.
Emergence of −s, −p–d band inversion in zincblende gold iodide topological insulator and its thermoelectric properties
Authors: Sattigeri Raghottam M , Gajaria Trupti K , Jha Prafulla K , Śpiewak Piotr , Kurzydłowski Krzysztof J
Published: January 2021

We employ first-principles calculations to investigate the topological states (TS) and thermoelectric (TE) transport properties of three dimensional (3D) gold iodide (AuI) which belongs to the zincblende family. We explore, semi-metal (SM) to topological conductor (TC) and topological insulator (TI) phase transitions. Under pristine conditions, AuI exhibits Dirac SM nature but, under the influence of mild isotropic compressive pressure the system undergoes electronic quantum phase transition driving it into non-trivial topological state. This state exhibits Dresselhaus like band spin splitting leading to a TC state. In order to realize TI state from the SM state, we break the cubic symmetry of the system by introducing a compressive pressure along (001) crystal direction. The non-trivial TI nature of the system is characterized by the emergence of robust surface states and the

Z

2

invariant ν
0 = 1 which indicates a strong TI nature. A novel facet of the phase transition discussed here is, the −s and −p, −d orbital band inversion mechanism which is unconventional as compared to previously explored TI families. This mechanism unravels new path by which TI materials can be predicted. Also, we investigated the lattice and electronic contributions to the TE transport properties. We characterize the TE performance by calculating the figure of merit (zT) and find that, at room temperature (300 K) and for a fixed doping concentration (i.e., n = 1 × 1019 cm−3) the zT is 0.55 and 0.53 for electrons and holes respectively. This is quite remarkable since, higher values of zT are generally predicted at higher temperature scales whereas, zT values as in the present case are desired at room temperatures for various energy applications. The manifestation of non-trivial TS governed by the unconventional band inversion mechanism and the TE properties of AuI make it a unique multi-functional candidate with probable thermoelectric and spintronic applications.
The National Dose Registry—Canadian occupational exposure to ionising radiation, 1998–2018
Authors: Chen Jing , Prendergast Tim , Prince Philippe , Gaw Adelene , Quayle Debora
Published: January 2021

The National Dose Registry (NDR) is owned and operated independently by Health Canada. This paper provides an overview of how the registry operates within the Canadian regulatory structure, followed by an analysis of annual effective dose trends in nine job classes with relatively higher mean annual effective doses, i.e. greater than 1 mSv as reported in 2017. The analysis showed that, with a few exceptions, mean annual effective doses have generally decreased or remained practically unchanged in the past two decades at relatively low exposure levels. This review of occupational dose trends is evidence of the effectiveness of radiation protection programmes in Canada. The NDR has played an important role in the identification of relatively higher dose records and allowed the regulatory bodies to act immediately to ensure appropriate actions were taken.
Improved multiscale weighted-dispersion entropy and its application in fault diagnosis of train bearing
Authors: Li Yongjian , Song Hao , Miao Bingrong , Zhang Weihua , Xiong Qing
Published: January 2021

Multiscale dispersion entropy (MDE) is a common method for measuring the complexity of nonlinear time series. However, the uncertainty results by the MDE tool may be unreliable as the coarse-graining procedure will reduce the number of data points at a large scale. In addition, the essential differences between the matching patterns cannot be extracted by MDE. To effectively alleviate the above limitations of MDE, an improved multiscale weighted-dispersion entropy (IMWDE) method is proposed in this article. Weight coefficients and weight probabilities were assigned to each vector to consider the amplitude information, and an improved coarse grained process is proposed for entropy value refinement. The performance of the IMWDE method is evaluated with synthetic data. Based on a powerful algorithm for key feature extraction, a novel intelligent diagnosis technique is proposed by combining classifiers. Finally, real vibration signals collected from axle-box bearings are used to demonstrate the effectiveness of the diagnosis scheme. Compared with MDE and IMWDE, the results indicate that the proposed method achieves smaller errors, and the highest diagnosis accuracy.
Investigation of measurement uncertainties in LNG density and energy for custody transfer
Authors: Wu Thomas Y , Kenbar Asaad
Published: January 2021

In the custody transfer of fuels such as liquefied natural gas (LNG), energy measurement accuracy is critical. The important elements in calculating transferred energy are the volume, the density and the superior calorific value (SCV). In this paper we have used a new approach to carefully study the various uncertainty factors contributing to two of these elements: the density and the SCV. For density, six methods were evaluated, namely the method of extended corresponding states, the Hiza method, the revised Klosek–McKinley method, the Groupe Européen de Recherche Gazière (GERG-2004) method, the GERG-2008 method, and the equation of state–LNG method, to estimate the modelling error in the density calculation. Other factors affecting LNG density estimation (LNG composition, reference densimeter, temperature and pressure) have also been investigated to derive the total uncertainty in LNG density estimation. For the SCV, the uncertainty has been analysed with consideration given to uncertainties in the composition and the SCV of LNG components. The expanded uncertainty in LNG energy during custody transfer is estimated to be 0.58% (k = 2) after considering the uncertainties due to the membrane-type tank’s unloaded LNG volume, SCV, density and their correlation effect.
Carbon diffusion in concentrated Fe–C glasses
Authors: Soltani Siavash , Rottler Jörg , Sinclair Chad W
Published: January 2021

By combining atomistic simulations with a detailed analysis of individual atomic hops, we show that the diffusion of carbon in a binary Fe–C glass exhibits strong (anti-)correlations and is largely determined by the local environment. Higher local carbon concentrations lead to slower atomic mobility. Our results help explain the increasing stability of Fe–C (and, potentially, other similar metal–metalloid glasses) against crystallization with increasing solute concentration.
Modelling the interactions and diffusion of NO in amorphous SiO2
Authors: Mistry M V , Cottom J , Patel K , Shluger A L , Sosso G C , Pobegen G
Published: January 2021

Nitric oxide (NO) is often used for the passivation of SiC/SiO2 metal oxide semiconductor (MOS) devices. Although it is established experimentally, using XPS, EELS, and SIMS measurements, that the 4H-SiC/SiO2 interface is extensively nitridated, the mechanisms of NO incorporation and diffusion in amorphous (a)-SiO2 films are still poorly understood. We used density functional theory (DFT) to simulate the incorporation and diffusion of NO through a-SiO2 and correlate local steric environment in amorphous network to interstitial NO (NO
i
) incorporation energy and migration barriers. Shapes and volumes of structural cages in amorphous structures are characterised using a methodology based on the Voronoi S-network. Using an efficient sampling technique we identify the energy minima and transition states for neutral and negatively charged NO
i
molecules. Neutral NO
i
interacts with the amorphous network only weakly with the smallest incorporation energies in bigger cages. On the other hand

N
O

i

−
1

binds at the network sites with wide O–Si–O bond angles, which also serve as the intrinsic precursor sites for electron trapping.
Nanocrystalline NiSe2/MoS2 heterostructures for electrochemical hydrogen evolution reaction
Authors: Huang Yazhou , Lv Junyan , Huang Jiacai , Xu Kunshan , Liu Lei
Published: January 2021

Although it suffers from a heavy dependence on the noble platinum catalyst, the electrochemical hydrogen evolution reaction (HER) is one of the most promising methods for the production of hydrogen. After numerous efforts, it is found that MoS2-based heterostructure may replace platinum as the electrochemical HER catalyst. In this work, the nanocrystalline NiSe2/MoS2 heterostructures were successfully prepared on the carbon fiber paper (CFP) substrate through electrochemical deposition and hydrothermal process. According to a series of electrochemical HER tests and a comparison with other MoS2-based heterostructure catalysts, the CFP/NiSe2/MoS2 catalyst with an overpotential η
10 of 143 mV and a Tafel slope of 45 mV dec−1 exhibited an excellent electrochemical HER catalytic performance and durability. In addition, CFP/NiSe2/MoS2 catalyst was treated by plasma to further improve the catalytic performance of the catalyst.
Transport model of plasma heating at the second harmonic of the electron cyclotron frequency
Authors: Dnestrovskij Yu N , Danilov A V , Dnestrovskij A Yu , Lysenko S E , Melnikov A V , Nemets A R , Nurgaliev M R , Subbotin G F , Solovev N A , Sychugov D Yu , Cherkasov S V
Published: January 2021

The optical thickness of the plasma is often insufficient to fully absorb the microwaves during heating at the second harmonic of the electron cyclotron frequency. An analysis of the experiments to the T-10 tokamak allows us to find the criteria for the full absorption, and to construct a canonical profile transport model for the full and partial absorptions of microwaves. The conditions to the equivalence of discharges in different tokamaks, and in a pair of tokamaks with the optimized W7-X stellarator are formulated. For equivalent discharges, calculations to the T-15MD tokamak under construction with the obtained model coincide with measurements of electron and ion temperatures in the W7-X over a wide range of plasma densities. The validated model is used to analyze future shots of T-15MD.
Electromagnetic emission due to nonlinear interaction of laser wakefields colliding in plasma at an oblique angle
Authors: Volchok E , Annenkov V , Timofeev I
Published: January 2021

Head-on collision of laser-induced plasma wakefields with differing profiles of electrostatic potential has been recently found to be an efficient mechanism for generating high-power electromagnetic emission at the second harmonic of the plasma frequency (Timofeev et al 2017 Phys. Plasmas
24 103106). This mechanism is attractive for creating a source of tunable narrow-band coherent radiation in the terahertz frequency range. In this paper, we generalize the theory of electromagnetic emission produced by non-linear interaction of two plasma wakes to the case of an arbitrary collision angle. Such a theory is used to evaluate the angular distribution of the second harmonic radiation as well as its total generation efficiency for parameters of the proof-of-principle experiment in which laser axes will be aligned with a small finite angle. Theoretical predictions are qualitatively confirmed by particle-in-cell simulations.
Multimillijoule terahertz radiation from laser interactions with microplasma waveguides
Authors: Hu Ke , Yi Longqing , Fülöp Tünde
Published: January 2021

When a relativistic, femtosecond laser pulse enters a waveguide, the pulse energy is coupled into waveguide optical modes. The longitudinal laser field effectively accelerates electrons along the axis of the channel, while the asymmetric transverse electromagnetic fields tend to expel fast electrons radially outwards. At the exit of the waveguide, the ∼nC, ∼10 MeV electron bunch converts its energy to a ∼10 mJ terahertz (THz) laser pulse through coherent diffraction radiation. In this paper, we present 3D particle-in-cell simulations and theoretical analyses of the aforementioned interaction process. We investigate the process of longitudinal acceleration and radial expulsion of fast electrons, as well as the dependence of the properties of the resulting THz radiation on laser and plasma parameters and the effects of the preplasma. The simulation results indicate that the conversion efficiency of energy can be over 5% if the waveguide length is optimal and a high contrast pump laser is used. These results guide the design of more intense and powerful THz sources.
Plasma rotation driven by rotating magnetic fields
Authors: Ren Baoming , Zhang Jiadong , Yang Zhida , Zhu Guanghui , Zhou Haiyang , Zheng Jian , Sun Xuan
Published: January 2021

We report a novel method to control plasma rotation speed, namely, using the rotating magnetic field (RMF), which is a mature technique to form field reversed configuration, to drive the electron rotation and then the ion rotation via electron–ion collisions in a magnetic mirror plasma. It can be observed that the plasma starts rotating if the RMF strength exceeds a threshold value, corresponding to which the value of the magnetization parameter becomes larger than the value of the penetration parameter. The flow speed achieved in this experiment is approximately 0.14 Mach. The rotation is found to start from outside to inside with the propagating time almost equal to the penetration time of the RMFs. Also, a clear sheared flow is observed to have developed in the region of core plasma. It has been further identified that the electron–ion friction is the dominant force to drive the ion spinning up. The rotation speed is primarily determined by the RMF strength, instead of background magnetic field strength, which may offer a method to study the effect of rotation on the confinement in different magnetic field strengths while keeping the rotation profile intact.
Design of selective-area growth compatible fully-vertical GaN p-i-n diodes with dielectric vertical sidewall appended edge termination schemes
Authors: Sarker Palash , Kelly Frank P , Landi Matthew , (Kevin) Kim Kyekyoon
Published: January 2021

While a slew of edge termination schemes for gallium nitride (GaN) power devices have been proposed and experimentally demonstrated to date, all of them suffer from the inability to achieve breakdown voltage close to ideal parallel-plane breakdown voltage. Further, they are exclusively processed using implantation or dry etching based methods, both of which are known to introduce additional defects and lattice damage leading to large leakage components. In this work, we develop and design novel dielectric vertical sidewall appended edge termination (DiVSET) schemes that are surface-charge resilient and capable of achieving ideal parallel-plane breakdown voltage. These edge termination schemes are compatible with plasma-assisted molecular-beam epitaxy facilitated silicon nitride shadowed selective-area growth (SNS-SAG) processing protocol, recently developed by us. The SNS-SAG protocol is uniquely capable of processing smooth, lattice damage-free GaN interfaces and vertical sidewalls that can reduce the leakage current by several orders of magnitude compared to conventional implant and dry etching based GaN processing. Together with the SNS-SAG processing, the DiVSET schemes offer an enabling technology for high-performance ultra-low leakage GaN power devices.
Competing anticlastic and piezoelectric deformation at large deflections
Authors: Salmani H , Hanke U , Halvorsen E
Published: January 2021

In bending of a purely elastic beam or plate, it is well established that the cross-sectional shape changes character with decreasing bending radius-of-curvature and that the transition can be characterized by the Searle parameter. In a piezoelectric structure, the cross-sectional deformation is affected by the opposite anticlastic and electromechanical bending curvatures. The behavior is consequently more complicated and it is an open question how the cross-sectional shape develops with increasing bending. In this paper, analytical solutions are used to study the cross-sectional deformation of piezoelectric cantilever-actuators taking both anticlastic and electromechanical bending effects into account. We consider unimorph and bimorph actuators. In the case of electrical actuation, as for the purely mechanical case, we find that the Searle parameter is an important parameter characterizing the shape of the cross-section. A load scaling rule gives a criterion for fixed cross-section-deflection for different actuator widths. Using this scaling rule, the Searle parameter is kept unchanged. The analytical results are verified by non-linear finite element analysis using electric potential and mechanical moment as applied loads.
Superconductivity in centrosymmetric topological superconductor candidate TaC
Authors: Yan D Y , Yang M , Wang C X , Song P B , Yi C J , Shi Y G
Published: January 2021

We report the synthesis and physical properties of the single crystals of TaC, which are proposed to hold topological band structure as a topological superconductor (TSC) candidate. Magnetization, resistivity and specific heat measurements are performed and indicate that TaC is bulk superconductor with critical temperature of 10.3 K. TaC is a strongly coupled type-II superconductor and the superconducting state can be well described by s-wave Bardeen–Cooper–Schrieffer theory with a single gap. The upper critical field (H
c2) of TaC shows linear temperature dependence, which is quite different from most conventional superconductors and isostructural NbC, which is proposed to manifest topological nodal-loops or type-II Dirac points as well as superconductivity. Our results suggest that TaC would be a new candidate for further research of TSCs.
Thermodynamics of a weakly interacting Bose gas above the transition temperature
Authors: Bulakhov M S , Peletminskii A S , Slyusarenko Yu V , Sotnikov A G
Published: January 2021

We study thermodynamic properties of weakly interacting Bose gases above the transition temperature of Bose–Einstein condensation in the framework of a thermodynamic perturbation theory. Cases of local and non-local interactions between particles are analyzed both analytically and numerically. We obtain and compare the temperature dependencies for the chemical potential, entropy, pressure, and specific heat to those of noninteracting gases. The results set reliable benchmarks for thermodynamic characteristics and their asymptotic behavior in dilute atomic and molecular Bose gases above the transition temperature.
Modulation instability analysis and longitudinal wave propagation in an elastic cylindrical rod modelled with Pochhammer-Chree equation
Authors: Seadawy Aly R , Rehman S U , Younis M , Rizvi S T R , Althobaiti Saad , Makhlouf M M
Published: January 2021

In this article, propagation of solitary wave solutions to the Pochhammer-Chree equation(PC) are investigated. Different kinds of solutions like bright-dark, kink, singular, hyperbolic, rational, trigonometric as well as Jacobi elliptic function solutions are obtained. The innovative methodology used to extract the solitary wave is known as Φ6-model expansion method. Moreover, the modulation instability (MI) analysis of governing equation is also discussed. Against the appropriate choices of parameters, two and three dimensional and contour graphs are also sketched. The obtained outcomes are more general and fresh and show that the applied method is concise, direct, elementary and can be imposed in more complex phenomena with the assistant of symbolic computations.
Lagrangian particle model for 3D simulation of pellets and SPI fragments in tokamaks
Authors: Samulyak R. , Yuan S. , Naitlho N. , Parks P.B.
Published: January 2021

A 3D numerical model for the ablation of pellets and shattered pellet injection fragments in tokamaks in the plasma disruption mitigation and fueling parameter space has been developed based on the Lagrangian particle (LP) method Samulyak et al (2018 J. Comput. Phys.
362 1–19). The pellet code implements the low magnetic Reynolds number MHD equations, kinetic models for the electronic heating, a pellet surface ablation model, an equation of state that supports multiple ionization states, radiation, and a model for grad-B drift of the ablated material across the magnetic field. The LP algorithm is highly adaptive, capable of simulating a large number of fragments in 3D while eliminating numerical difficulties of dealing with the tokamak background plasma. The code has achieved good agreement with theory for spherically symmetric ablation flows. Axisymmetric simulations of neon and deuterium pellets in magnetic fields ranging from 1 to 6 Tesla have been compared with previous simulations using the FronTier code, and very good agreement has also been obtained. The main physics contribution of the paper is a detailed study of the influence of 3D effects, in particular grad-B drift, on pellet ablation rates and properties of ablation clouds. Smaller reductions of ablation rates in magnetic fields compared to axially symmetric simulations have been demonstrated because the ablated material is not confined to narrowing channels in the presence of grad-B drift. Contribution of various factors in the grad-B drift model has also been quantified.
Recent advances on drug delivery nanocarriers for cerebral disorders
Authors: Zhou Zheng , Sun Tao , Jiang Chen
Published: January 2021

Pharmacotherapies for brain disorders are generally faced with obstacles from the blood-brain barrier (BBB). There are a variety of drug delivery systems that have been put forward to cross or bypass the BBB with the access to the central nervous system. Brain drug delivery systems have benefited greatly from the development of nanocarriers, including lipids, polymers and inorganic materials. Consequently, various kinds of brain drug delivery nano-systems have been established, such as liposomes, polymeric nanoparticles (PNPs), nanomicelles, nanohydrogels, dendrimers, mesoporous silica nanoparticles and magnetic iron oxide nanoparticles. The characteristics of their carriers and preparations usually differ from each other, as well as their transportation mechanisms into intracerebral lesions. In this review, different types of brain drug delivery nanocarriers are classified and summarized, especially their significant achievements, to present several recommendations and directions for future strategies of cerebral delivery.