bluuebunny/crossref_metadata_2025 huggingface dataset:
Job Satisfaction and Evidence of Burnout Comparing Arab and Non-Arab Urologists with a Migration Background Working in German Hospitals
Authors: May Matthias , Shaar Mohammad
Published: October 2021

Background In German hospitals, severe shortage of physicians can currently be partially compensated by hiring foreign physicians. Results on job satisfaction (JS) and physician burnout (PBO) in this important occupational group are currently not available.

Methods The cross-sectional “Assessment of their urological work environment by foreign clinicians in Germany (EUTAKD)” study was conducted in 2020 using a 101-item questionnaire among physicians working in German urological departments who were born in a country outside Germany and having non-German citizenship. This study compared JS and the occurrence of PBO between Arab (group A, n = 57) and non-Arab (group B, n = 39) participants.

Results Significant group differences with advantages for group B were analyzed in overall JS and also in other JS items. High scores in the PBO dimensions, that is, “emotional exhaustion” and “depersonalization,” were shown by 27.9 and 51.5% of the study participants, respectively, although there were no group differences found (p = 0.972 and 0.237, respectively).

Conclusion Prospective longitudinal studies of appropriate intervention measures aimed at increasing JS and decreasing PBO are needed.
Conservative Treatment of a Floating Mural Thrombus in the Descending Aorta
Authors: Goedemé Johannes , Berzenji Lawek , Nicolay Simon , Hendriks Jeroen M.H.
Published: October 2021

A 70-year-old woman was referred to the department of thoracic and vascular surgery after a floating mural thrombus was found in the distal aortic arch with extension into the proximal descending aorta. Imaging and clinical examination did not show signs of embolization and treatment with aspirin and low–molecular weight heparin was started. Follow-up after 2 weeks and 6 months showed a complete resolution of the aortic mural thrombus.
Sound-reflecting mirror could amplify contactless energy transfer capabilities
Authors: Lim Alane
Published: October 2021

Holographic acoustic mirror design enables fine manipulation of ultrasonic waves.
Anisotropic terahertz transmission induced by the external magnetic field in La0.67Ca0.33MnO3 film
Authors: Mei Hongying , Zhang Peng , Zhang Shile , Yao Ruxian , Yao Haizi , Chen Feng , Wang Zhenyou , Su Fuhai
Published: October 2021

A systemic investigation of the terahertz (THz) transmission of La0.67Ca0.33MnO3 film on the (001)-oriented NdGaO3 substrate under external magnetic field and low temperature have been performed. The significant THz absorption difference between the out-of-plane and the in-plane magnetic field direction is observed, which is consistent with the electrical transport measurement using the standard four-probe technique. Furthermore, we find that the complex THz conductivities can be reproduced in terms of the Drude Smith equation as the magnetic field is perpendicular to the film plane, whereas it deviates from this model when the in-plane magnetic field is applied. We suggest that such anisotropies in THz transport dynamics have close correspondences with the phase separation and anisotropic magnetoresistance effects in the perovskite-structured manganites. Our work demonstrates that the THz time-domain spectroscopy (TDS) can be an effective non-contact method for studying the magneto-transport properties of the perovskite-structured manganites.
Solar-blind field-assisted NEA AlGaN heterojunction nanocone array photocathode
Authors: Liu Lei , Zhangyang Xingyue , Lv Zhisheng , Lu Feifei , Tian Jian
Published: October 2021

With the abundant utilization of ultraviolet detectors, the proposal for designing vacuum photoelectron emitting devices with efficient solar blind detection performance continues to increase. To alleviate the phenomenon of “secondary absorption” where photoelectrons are absorbed by an adjacent nanocone, in general, nanocone arrays, the theoretical model of the field-assisted negative electron affinity Alx1Ga1−x1N/Alx2Ga1−x2N heterojunction nanocone array photocathode is established. The built-in electric field of the heterojunction nanocone directed from top to bottom is utilized to promote the drifting of photocurrent along the nanocone, and the external electric field induced by a silver electrode is expected to enhance the probability of electron collection. The results show that the electron collection ratio is enhanced and the electron collection efficiency of the nanocone photocathode is improved, which proves the effectiveness of the applied electric field. This work could turn into the theoretical guidance of the design and manufacture of high-performance solar-blind ultraviolet detectors.
Generalizations of parabolic Higgs bundles, real structures, and integrability
Authors: Levin A. , Olshanetsky M. , Zotov A.
Published: October 2021

We introduce a notion of quasi-antisymmetric Higgs G-bundles over curves with marked points. They are endowed with additional structures that replace the parabolic structures at marked points in parabolic Higgs bundles. This means that the coadjoint orbits are attached to the marked points of the curves. The moduli spaces of parabolic Higgs bundles are the phase spaces of complex completely integrable systems. In our case, the coadjoint orbits are replaced by bundles cotangent to some special symmetric spaces in such a way that the moduli space of the modified Higgs bundles are still phase spaces of complex completely integrable systems. We show that the moduli space of parabolic Higgs bundles is the symplectic quotient of the moduli space of the quasi-antisymmetric Higgs bundle with respect to the action of the product of Cartan subgroups. In addition, by changing the symmetric spaces, we introduce quasi-compact and quasi-normal Higgs bundles. The fixed point sets of real involutions acting on their moduli spaces are the phase spaces of real completely integrable systems. Several examples are given including integrable extensions of the SL(2) Euler–Arnold top, two-body elliptic Calogero–Moser system, and the rational SL(2) Gaudin system together with its real reductions.
Perspectives for next generation lithium-ion battery cathode materials
Authors: Booth Samuel G. , Nedoma Alisyn J. , Anthonisamy Nirmalesh N. , Baker Peter J. , Boston Rebecca , Bronstein Hugo , Clarke Simon J. , Cussen Edmund J. , Daramalla Venkateswarlu , De Volder Michael , Dutton Siân E. , Falkowski Viktoria , Fleck Norman A. , Geddes Harry S. , Gollapally Naresh , Goodwin Andrew L. , Griffin John M. , Haworth Abby R. , Hayward Michael A. , Hull Stephen , Inkson Beverley J. , Johnston Beth J. , Lu Ziheng , MacManus-Driscoll Judith L. , Martínez De Irujo Labalde Xabier , McClelland Innes , McCombie Kirstie , Murdock Beth , Nayak Debasis , Park Seungkyu , Pérez Gabriel E. , Pickard Chris J. , Piper Louis F. J. , Playford Helen Y. , Price Simon , Scanlon David O. , Stallard Joe C. , Tapia-Ruiz Nuria , West Anthony R. , Wheatcroft Laura , Wilson Megan , Zhang Li , Zhi Xuan , Zhu Bonan , Cussen Serena A.
Published: October 2021

Transitioning to electrified transport requires improvements in sustainability, energy density, power density, lifetime, and approved the cost of lithium-ion batteries, with significant opportunities remaining in the development of next-generation cathodes. This presents a highly complex, multiparameter optimization challenge, where developments in cathode chemical design and discovery, theoretical and experimental understanding, structural and morphological control, synthetic approaches, and cost reduction strategies can deliver performance enhancements required in the near- and longer-term. This multifaceted challenge requires an interdisciplinary approach to solve, which has seen the establishment of numerous academic and industrial consortia around the world to focus on cathode development. One such example is the Next Generation Lithium-ion Cathode Materials project, FutureCat, established by the UK’s Faraday Institution for electrochemical energy storage research in 2019, aimed at developing our understanding of existing and newly discovered cathode chemistries. Here, we present our perspective on persistent fundamental challenges, including protective coatings and additives to extend lifetime and improve interfacial ion transport, the design of existing and the discovery of new cathode materials where cation and cation-plus-anion redox-activity can be exploited to increase energy density, the application of earth-abundant elements that could ultimately reduce costs, and the delivery of new electrode topologies resistant to fracture which can extend battery lifetime.
Hardware for cell culture electrical impedance tomography: A critical review
Authors: Morcelles K. F. , Bertemes-Filho P.
Published: October 2021

Human cell cultures are powerful laboratory tools for biological models of diseases, drug development, and tissue engineering. However, the success of biological experiments often depends on real-time monitoring of the culture state. Conventional culture evaluation methods consist of end-point laborious techniques, not capable of real-time operation and not suitable for three-dimensional cultures. Electrical Impedance Tomography (EIT) is a non-invasive imaging technique with high potential to be used in cell culture monitoring due to its biocompatibility, non-invasiveness, high temporal resolution, compact hardware, automatic operation, and high throughput. This review approaches the different hardware strategies for cell culture EIT that are presented in the literature, discussing the main components of the measurement system: excitation circuit, voltage/current sensing, switching stage, signal specifications, electrode configurations, measurement protocols, and calibration strategies. The different approaches are qualitatively discussed and compared, and design guidelines are proposed.
Analysis of chaotic dynamical systems with autoencoders
Authors: Almazova N. , Barmparis G. D. , Tsironis G. P.
Published: October 2021

We focus on chaotic dynamical systems and analyze their time series with the use of autoencoders, i.e., configurations of neural networks that map identical output to input. This analysis results in the determination of the latent space dimension of each system and thus determines the minimal number of nodes necessary to capture the essential information contained in the chaotic time series. The constructed chaotic autoencoders generate similar maximal Lyapunov exponents as the original chaotic systems and thus encompass their essential dynamical information.
Synchronization of nonlinearly coupled networks based on circle criterion
Authors: Plotnikov Sergei A. , Fradkov Alexander L.
Published: October 2021

The problem of synchronization in networks of linear systems with nonlinear diffusive coupling and a connected undirected graph is studied. By means of a coordinate transformation, the system is reduced to the form of mean-field dynamics and a synchronization-error system. The network synchronization conditions are established based on the stability conditions of the synchronization-error system obtained using the circle criterion, and the results are used to derive the condition for synchronization in a network of neural-mass-model populations with a connected undirected graph. Simulation examples are presented to illustrate the obtained results.
Nonlinear transmission line implemented as a combined pulse forming line and high-power microwave source
Authors: Fairbanks Andrew J. , Crawford Travis D. , Garner Allen L.
Published: October 2021

Nonlinear transmission lines (NLTLs) are typically driven by pulse forming lines (PFLs) or Marx generators to generate high repetition rate, high power microwaves (HPMs) with fewer auxiliary systems than conventional sources. This paper reports the development of an even more compact HPM system that utilizes a composite-based hybrid NLTL as the PFL and HPM generator in a single device. We designed the following three different combinations of nickel zinc ferrite (NZF) and barium strontium titanate (BST) inclusion volume loads in a polydimethylsiloxane host material to provide magnetic field dependent permeability and electric field dependent permittivity, respectively: 25% NZF, 10% BST/15% NZF, and 15% BST/10% NZF. By constructing the NLTL in a coaxial geometry, this device uses the capacitance and length of the NLTL to generate a fast rise-time high voltage pulse with microwave oscillations that occurred both during and after the pulse after exceeding a threshold charging voltage. The output frequency of the NLTLs ranged from 950 MHz to 2.2 GHz during the pulse for all volume loadings and was 1 GHz after the pulse for the 10% BST/15% NZF and 15% BST/10% NZF volume loadings. The oscillations generated after the pulse were much higher in amplitude and achieved 160 kW at a 15 kV charging voltage for the 15% BST/10% NZF composite-based NLTL.
Dual-channel Faraday rotation measurement for pulsed magnetic field
Authors: Zhang Jue , Zhao Xincai , Chen Guanghua , Peng Qixian
Published: October 2021

The immunity and survivability in a strong electromagnetic environment make the Faraday Rotation (FR) method irreplaceable for measuring pulsed magnetic fields. We present a dual-channel FR method that achieves more stable and precise measurement and more applicable magnetic field types than the conventional FR method. By splitting the modulated light into two components, the ratio of the two components is transformed into a tangent function with two analyzers at a relative 45°. The use of terbium gallium garnet, which has a significant magneto-optical effect, as a magneto-optical medium enables higher sensitivity for measurement. We have successfully measured the variation in magnetic flux density of the capacitively driven pulsed magnetic field.
Modeling of a tunable memory device made with a double-gate MoS2 FET and graphene floating gate
Authors: Rodder Michael A. , Dodabalapur Ananth
Published: October 2021

Electronic devices comprising low-temperature processed 2D materials can be utilized in back-end-of-line nonvolatile memory and logic applications, to augment conventional silicon technology. A promising structure for a low-temperature processed digital nonvolatile flash memory device and/or logic device is the double-gate MoS2 FET with a graphene floating gate and a thin h-BN gate dielectric serving as a tunneling dielectric. In this work, we show that experimental hysteretic current–voltage characteristics of this digital flash memory device can be well fit by a simple and effective physics-based model using a WKB approximation to calculate the tunneling current to the graphene floating gate and a capacitive network with 2D density-of-states to calculate the channel current flowing in the MoS2 channel. Accordingly, the model allows a device designer to predict and/or tune characteristics for this memory device, e.g., the width and center-position of the hysteresis loop as well as the value of source–drain current, as a function of both the bottom (control) gate and top (FET) gate voltages. It is noted that shifting of the center-position of the hysteresis loop enables improved reliability and functionality of the memory device in circuit applications and is a unique feature of this double-gated MoS2 FET. Overall, the demonstrated ability to well model this memory device lends further credence that 2D devices could augment silicon technology.
Machine learning based accurate recognition of fractional optical vortex modes in atmospheric environment
Authors: Cao Meng , Yin Yaling , Zhou Jingwen , Tang Jihong , Cao Luping , Xia Yong , Yin Jianping
Published: October 2021

Optical vortex beam with fractional orbital angular momentum (OAM) has great potential to increase the capacity of optical communication and information processing in classical and quantum regimes. However, atmospheric turbulence (AT) in free space distorts the helical phase-front of vortex beams and causes the mode diffusion, seriously hindering the practical application. Herein, using a convolutional neural network approach with an improved residual neural network architecture, we overcome the hurdle to give the accurate recognition of the fractional OAM in the AT. As demonstrated on the petal interference patterns, a type of hybrid beams carrying double OAM modes is utilized to provide two controllable degrees of freedom for greater recognition of more subtle OAM modes, e.g., the fractional topological charge number l and the angular ratio n. Our studies show that with various l and n, the recognition accuracy of OAM over 20 000 images is as high as 85.30% even under the strong AT parameter (Cn2 = 5 × 10−14 m−2/3) and the long propagation distance (z = 1500 m). Our findings represent a remarkable achievement toward highly accurate recognition of fractional OAM with broad bandwidth in the atmospheric environment, expanding the applications for the general interest of machine learning based OAM optical communication.
Optical and electrical characterizations of micro-LEDs grown on lower defect density epitaxial layers
Authors: Gandrothula Srinivas , Kamikawa Takeshi , Shapturenka Pavel , Anderson Ryan , Wong Matthew , Zhang Haojun , Speck James S. , Nakamura Shuji , Denbaars Steven P.
Published: October 2021

We have fabricated μLEDs of mesa sizes 10 × 10 and 15 × 15 μm2 on native (2021¯) semipolar substrates and on epitaxial lateral overgrown (ELO) wings of the (2021¯) substrate. The ELO μLEDs exhibited very low leakage current (less than 10−10 A) under forward bias (V < 2 V) and at reverse bias voltages, which was a reduction in several orders of magnitude when compared with planar μLEDs under the same fabrication and sidewall passivation scheme. Electrical characterization revealed that the mesa sidewall is less damaged in plasma dry etching in the ELO μLEDs due to a lower material defect density than the planar μLEDs. Moreover, the ELO μLEDs showed improved optical performance over the planar μLEDs.
Compact generators of high-power fast-rising pulses with closing switches in the form of reversely switched dynistors
Authors: Korotkov S. V. , Zhmodikov A. L.
Published: October 2021

This paper presents the results of a study of reversely switched dynistors (RSDs) with an operating voltage of 2.3 kV and a structure diameter of 12 mm in an unconventional mode, when they commutate current pulses with very short durations (a few microseconds). In this mode, we studied the dependence of the switching energy loss on the amount of charge that passes through the RSDs during the flow of the control current, which is reversed with respect to the main current. It is shown that a sufficiently powerful control action will result in the RSDs under study having a very low energy loss and being able to effectively commutate microsecond current pulses with an amplitude of >10 kA. It is found that if a rise time of the commutated current pulses is less than 200 ns, the efficiency of the RSD switching significantly decreases. The results concerning the use of the RSDs under study in high-voltage generators are presented. The generators are able to commutate a pulsed power of tens of MW in less than 1 µs at a repetition rate of hundreds of Hz. Finally, this paper suggests ways to increase the power of generators.
Reduced quantum defect in a Yb-doped fiber laser by balanced dual-wavelength excitation
Authors: Yu Nanjie , Desai Kavita V. , Mironov Andrey E. , Xiong Mingye , Cavillon Maxime , Hawkins Thomas , Ballato John , Eden J. Gary , Dragic Peter D.
Published: October 2021

Two color optical pumping, both above (anti-Stokes pump or ASP) and below (Stokes pump) the lasing wavelength, was adopted to reduce the net quantum defect (QD) in a solid-state Yb-doped fiber laser. The reduction in QD was achieved by converting a substantial portion of the gain medium's phonons directly into useful photons through a dual-wavelength excitation (DWE) mechanism. Since this is achieved through the usual processes of absorption and stimulated emission associated with lasing, high efficiency can be maintained. Both time domain and power measurements are presented, demonstrating a 13.2% reduction of the system's net QD and a 13.8% reduction in the lasing threshold power. These values were limited only by the available ASP power. Laser slope efficiency, with respect to launched ASP power, was found to be as high as 38.3%. A finite difference time domain model, developed to elucidate the role of both pumps in populating the upper states, corroborated the experimental findings. The DWE concept proposed here opens the door to an “excitation-balanced” type of self-cooled fiber laser. Simulation results also suggest that the technique is scalable and conceptually applicable to other solid-state laser systems.
Understanding the role of mass transport in tuning the hydrogen evolution kinetics on gold in alkaline media
Authors: Goyal Akansha , Koper Marc T. M.
Published: October 2021

In this work, we present an in-depth study of the role of mass transport conditions in tuning the hydrogen evolution kinetics on gold by means of rotation rate control. Interestingly, we find that the hydrogen evolution reaction (HER) activity decreases with the increasing rotation rate of the electrode. As we increase the rotation (mass transport) rate, the locally generated hydroxyl ions (2H2O +2e− → H2 + 2OH−) are transported away from the electrode surface at an accelerated rate. This results in decreasing local pH and, because of the need to satisfy local electroneutrality, decreasing near-surface cation concentration. This decrease in the near-surface cation concentration results in the suppression of HER. This is because the cations near the surface play a central role in stabilizing the transition state for the rate determining Volmer step (*H–OHδ−–cat+). Furthermore, we present a detailed analytical model that qualitatively captures the observed mass transport dependence of HER solely based on the principle of electroneutrality. Finally, we also correlate the cation identity dependence of HER on gold (Li+ < Na+ < K+) to the changes in the effective concentration of the cations in the double layer with the changes in their solvation energy.
The effect of Schmidt number on gravity current flows: The formation of large-scale three-dimensional structures
Authors: Marshall C. R. , Dorrell R. M. , Dutta S. , Keevil G. M. , Peakall J. , Tobias S. M.
Published: October 2021

The Schmidt number, defined as the ratio of scalar to momentum diffusivity, varies by multiple orders of magnitude in real-world flows, with large differences in scalar diffusivity between temperature, solute, and sediment driven flows. This is especially crucial in gravity currents, where the flow dynamics may be driven by differences in temperature, solute, or sediment, and yet the effect of Schmidt number on the structure and dynamics of gravity currents is poorly understood. Existing numerical work has typically assumed a Schmidt number near unity, despite the impact of Schmidt number on the development of fine-scale flow structure. The few numerical investigations considering high Schmidt number gravity currents have relied heavily on two-dimensional simulations when discussing Schmidt number effects, leaving the effect of high Schmidt number on three-dimensional flow features unknown. In this paper, three-dimensional direct numerical simulations of constant-influx solute-based gravity currents with Reynolds numbers 100≤Re≤3000 and Schmidt number 1 are presented, with the effect of Schmidt number considered in cases with (Re,Sc)=(100,10), (100,100), and (500, 10). These data are used to establish the effect of Schmidt number on different properties of gravity currents, such as density distribution and interface stability. It is shown that increasing Schmidt number from 1 leads to substantial structural changes not seen with increased Reynolds number in the range considered here. Recommendations are made regarding lower Schmidt number assumptions, usually made to reduce computational cost.
Sloshing in vertical cylinders with circular walls: The effect of radial baffles
Authors: Kuznetsov Nikolay G. , Motygin Oleg V.
Published: October 2021

The behavior of sloshing eigenvalues and eigenfunctions is studied for vertical cylindrical containers that have circular walls and constant (possibly infinite) depth. The effect of breaking the axial symmetry due to the presence of radial baffles is analyzed. It occurs that the lowest eigenvalues are substantially smaller for containers with baffles going throughout the depth; moreover, all eigenvalues are simple in this case. On the other hand, the lowest eigenvalue has multiplicity two in the absence of baffle. It is shown how these properties affect the location of maxima and minima of the free surface elevation and the location of its nodes.
Excellent surface passivation of germanium by a-Si:H/Al2O3 stacks
Authors: Berghuis Wilhelmus J. H. (Willem-Jan) , Melskens Jimmy , Macco Bart , Theeuwes Roel J. , Black Lachlan E. , Verheijen Marcel A. , Kessels Wilhelmus M. M. (Erwin)
Published: October 2021

Surface passivation of germanium is vital for optimal performance of Ge based optoelectronic devices especially considering their rapidly increasing surface-to-volume ratios. In this work, we have investigated the surface passivation of Ge by a stack consisting of a thin layer of hydrogenated amorphous silicon (a-Si:H) and an aluminum oxide (Al2O3) capping layer. Plasma-enhanced chemical vapor deposition was used to deposit the a-Si:H (0–10 nm), while thermal and plasma-enhanced atomic layer deposition (ALD) were employed for the Al2O3 films (0–22 nm). Transient photoconductance decay measurements revealed a recombination velocity as low as 2.7 cm s−1 for an a-Si:H layer as thin as 1.8 nm and an Al2O3 film of only ∼6 nm. In this state-of-the-art passivation scheme, the plasma-enhanced ALD process for the Al2O3 capping layer proved superior to the thermal ALD process since it resulted in an exceptionally high negative fixed charge density (Qf ∼ 1013 cm−2), which proved a key factor for the low surface recombination velocity. Transmission electron microscopy and energy x-ray dispersion revealed that a thin SiOx layer (∼1.4 nm) forms between a-Si:H and Al2O3 during the ALD process, which is thought to be the origin of this high negative fixed charge density. This passivation stack is regarded as highly interesting for applications such as solar cells, nanolasers, and nano-LEDs based on p-type Ge.
Structure and conformational properties of ideal nanogel particles in athermal solutions
Authors: Chremos Alexandros , Horkay Ferenc , Douglas Jack F.
Published: October 2021

We investigate the conformational properties of “ideal” nanogel particles having a lattice network topology by molecular dynamics simulations to quantify the influence of polymer topology on the solution properties of this type of branched molecular architecture. In particular, we calculate the mass scaling of the radius of gyration (Rg), the hydrodynamic radius, as well as the intrinsic viscosity with the variation of the degree of branching, the length of the chains between the branched points, and the average mesh size within these nanogel particles under good solvent conditions. We find competing trends between the molecular characteristics, where an increase in mesh size or degree of branching results in the emergence of particle-like characteristics, while an increase in the chain length enhances linear polymer-like characteristics. This crossover between these limiting behaviors is also apparent in our calculation of the form factor, P(q), for these structures. Specifically, a primary scattering peak emerges, characterizing the overall nanogel particle size. Moreover, a distinct power-law regime emerges in P(q) at length scales larger than the chain size but smaller than Rg of the nanogel particle, and the Rg mass scaling exponent progressively approaches zero as the mesh size increases, the same scaling as for an infinite network of Gaussian chains. The “fuzzy sphere” model does not capture this feature, and we propose an extension to this popular model. These structural features become more pronounced for values of molecular parameters that enhance the localization of the branching segments within the nanogel particle.
Quantitative prediction of solid solubility limit in single phase high-entropy alloys
Authors: Li Jian-Hong , Chang Ting , Wu Ze-Chen , Tsai Ming-Hung
Published: October 2021

A thermodynamic model that can predict the solid solubility limit (SSL) in single phase HEAs is proposed. The accuracies of our model and other representative existing models were verified experimentally using a model single phase FCC alloy and 11 alloying elements. The results show that existing models substantially overestimate the SSLs in HEAs, leading to large prediction errors. In contrast, our model has considerably higher accuracy. The mean absolute prediction error for our model is only 2.9 at. %—less than 1/8 that of the best existing model. These results demonstrate that quantitative prediction is achievable through the present model.
Compressibility in suddenly expanded subsonic flows
Authors: Karantonis Konstantinos , Kokkinakis Ioannis W. , Thornber Ben , Drikakis Dimitris
Published: October 2021

This paper concerns implicit large eddy simulations of subsonic flows through a symmetric suddenly expanded channel. We aim at shedding light on the flow physics at a relatively high Reynolds number of 10 000, based on the inlet bulk velocity and the step height of the channel, and examine the compressibility effects for two Mach numbers, Ma = 0.1 and Ma = 0.5. Comparisons with experimental measurements are provided. In addition, we investigate the structure of the separated regions, turbulence structures—through the Reynolds stress anisotropy componentality—and turbulence kinetic energy budgets. The results reveal that compressibility influences particular flow physics.
Large-eddy simulation of a multi-injection flame in a diesel engine environment using an unsteady flamelet/progress variable approach
Authors: Wen Xu , Gierth Sandro , Rieth Martin , Chen Jacqueline H. , Hasse Christian
Published: October 2021

In this work, large-eddy simulations (LESs) are conducted for a multiple-injection flame in a diesel engine environment using an unsteady flamelet/progress variable (UFPV) approach in which differential diffusion is considered. The suitability of the UFPV tabulation approach is first evaluated through a priori analyses using the state-of-the-art direct numerical simulation (DNS) dataset. Both the instantaneous data and the conditional values for the major and minor species' mass fractions are compared between the UFPV and the DNS. The comparisons show that the proposed UFPV tabulation approach can give good predictions for the multiple-injection flame at different injection phases. While the gas temperature and major species mass fractions can be accurately predicted with or without differential diffusion being considered in the UFPV flamelet library, the prediction accuracy for the highly diffusive species (e.g., hydrogen) in the main injection phase can be noticeably improved when differential diffusion is taken into account. The fully coupled LES/UFPV simulations show that the overall structure of the multiple-injection flame can be predicted, and the conditional thermo-chemical values are close to the filtered DNS dataset. The reasons for the remaining discrepancies found in the a priori analyses and the a posteriori simulations using the UFPV approach are analyzed.
Near-field thermal radiation of gradient refractive index slab: Internal polaritons
Authors: Xu Deyu , Zhao Junming , Liu Linhua
Published: October 2021

We investigate near-field thermal radiation of gradient refractive index slabs (GRISs). It is demonstrated that internal polaritons (IPs) can be supported in the interior of GRISs. IPs provide more evanescent electromagnetic states especially in the lower frequency region and cause red-shift in the near-field heat flux spectrum, as well as enhance local absorption inside the medium. This work sheds light on the mechanism of near-field thermal radiation between GRISs and provides additional design freedom for near-field energy devices.
Effects of surface diffusion in electrocatalytic CO2 reduction on Cu revealed by kinetic Monte Carlo simulations
Authors: Li Jinghan , Maresi Ilaria , Lum Yanwei , Ager Joel W.
Published: October 2021

Kinetic Monte Carlo (KMC) methods are frequently used for mechanistic studies of thermally driven heterogeneous catalysis systems but are underused for electrocatalysis. Here, we develop a lattice KMC approach for electrocatalytic CO2 reduction. The work is motivated by a prior experimental report that performed electroreduction of a mixed feed of 12CO2 and 13CO on Cu; differences in the 13C content of C2 products ethylene and ethanol (Δ13C) were interpreted as evidence of site selectivity. The lattice KMC model considers the effect of surface diffusion on this system. In the limit of infinitely fast diffusion (mean-field approximation), the key intermediates 12CO* and 13CO* would be well mixed on the surface and no evidence of site selectivity could have been observed. Using a simple two-site model and adapting a previously reported microkinetic model, we assess the effects of diffusion on the relative isotope fractions in the products using the estimated surface diffusion rate of CO* from literature reports. We find that the size of the active sites and the total surface adsorbate coverage can have a large influence on the values of Δ13C that can be observed. Δ13C is less sensitive to the CO* diffusion rate as long as it is within the estimated range. We further offer possible methods to estimate surface distribution of intermediates and to predict intrinsic selectivity of active sites based on experimental observations. This work illustrates the importance of considering surface diffusion in the study of electrochemical CO2 reduction to multi-carbon products. Our approach is entirely based on a freely available open-source code, so will be readily adaptable to other electrocatalytic systems.
Considering the new minimum staffing standards for Australian residential aged care
Authors: Sutton Nicole , Ma Nelson , Yang Jin Sug , Rawlings-Way Olivia , Brown David , McAllister Gillian , Parker Deborah , Lewis Rachael
Published: October 2021

Objective To compare the historical staffing patterns and organisational characteristics of Australian residential aged care facilities (RACFs) against the new minimum staffing standards recommended by the Royal Commission into Aged Care Quality and Safety (RCACQS). Method Retrospective data analysis was used to compare the staffing levels and characteristics of 1705 RACFs (for 4 years, 2016–19) with the three new mandatory staffing requirements. De-identified datasets were provided by the RCACQS, obtained under its legal authority. Results Only 3.8% of RACFs have staffing levels at or above all three requirements. Although many (79.7%) already meet the requirement to have a registered nurse (RN) on-site for morning and afternoon shifts, few have staffing levels above requirements for total direct care per resident per day (10.4%) or care provided by an RN per resident per day (11.1%). Historical levels of on-site RNs, total direct care, and RN care vary significantly across facilities of different size, location and provider scale. Conclusion The new staffing standards, to be mandatory by 2023, prescribe minimum requirements significantly higher than existing levels, particularly in care per resident per day. Each of the three requirements will likely have a differential effect for different types of RACFs. What is known about the topic? International evidence suggests that introducing mandatory minimum staffing standards tends to increase the amount of care provided by staff in residential aged care facilities (RACFs). However, the impact of staffing standards is influenced by the stringency of the minimum threshold relative to existing staffing levels, the capacity of organisations to increase their staffing levels, and the specific way the regulation is formulated. What does this paper add? This paper explores the potential implications of the three national minimum staffing standards, to be in force by October 2023, specifying total direct care, care received by a registered nurse (RN), and an RN on-site. By examining the existing staffing levels of Australian RACFs, it identifies the extent to which facilities already meet the new standards and the characteristics of facilities with staffing levels above and below the three requirements (individually and in combination). What are the implications for practitioners? The study informs both policy and practice in relation to the likely effects of implementing the national minimum staffing standards for residential aged care in Australia. It demonstrates that the new minimum thresholds are likely to require substantial increases in staffing across the sector, both in terms of all direct care workers and RNs. It also shows that the three requirements are likely to have a differential effect for RACFs of different size, location and chain affiliation, thereby guiding policy about the future needs for Australia’s aged care workforce.
No evidence for colonization of oral bacteria in the distal gut in healthy adults
Authors: Rashidi Armin , Ebadi Maryam , Weisdorf Daniel J. , Costalonga Massimo , Staley Christopher
Published: October 2021

The microbial communities in the mouth and colon are anatomically connected via the saliva. However, the extent to which oral microbes reach and successfully colonize the distal gut has been debated. To resolve this long-standing controversy, we used exact amplicon sequence variants generated from concurrently collected saliva/stool microbiota in 66 healthy adults from two countries to show that, with one exception (
Dialister invisus
), the two niches are completely distinct. Thus, there is no evidence for colonization of oral bacteria in the distal gut. This defines the healthy state to which pathological states could be compared. Finding the same bacteria in the mouth and stool may warrant clinical investigation for an underlying pathology.
The Strategic Council for Research Excellence, Integrity, and Trust
Authors: McNutt Marcia , Córdova France A. , Allison David B.
Published: October 2021

We announce the creation of a new body within the National Academies of Sciences, Engineering, and Medicine called the Strategic Council for Research Excellence, Integrity, and Trust, charged with advancing the overall health, quality, and effectiveness of the research enterprise across all domains that fund, execute, disseminate, and apply scientific work in the public interest. By promoting the alignment of incentives and policies, adoption of standard tools, and implementation of proven methods, the Strategic Council seeks to optimize the excellence and trustworthiness of research for the benefit of society.
Article Commentary: Research Priorities for Expanding access to Methadone Treatment for Opioid use Disorder in the United States: A National Institute on Drug Abuse Clinical Trials Network Task Force Report
Authors: Joudrey Paul J. , Bart Gavin , Brooner Robert K. , Brown Lawrence , Dickson-Gomez Julie , Gordon Adam , Kawasaki Sarah S. , Liebschutz Jane M. , Nunes Edward , McCarty Dennis , Schwartz Robert P. , Szapocnik José , Trivedi Madhukar , Tsui Judith I. , Williams Arthur , Wu Li-Tzy , Fiellin David A.
Published: October 2021

In the US, methadone treatment can only be provided to patients with opioid use disorder (OUD) through federal and state-regulated opioid treatment programs (OTPs). There is a shortage of OTPs, and racial and geographic inequities exist in access to methadone treatment. The National Institute on Drug Abuse Clinical Trials Network convened the Methadone Access Research Task Force to develop a research agenda to expand and create more equitable access to methadone treatment for OUD. This research agenda included mechanisms that are available within and outside the current regulations. The task force identified 6 areas where research is needed: (1) access to methadone in general medical and other outpatient settings; (2) the impact of methadone treatment setting on patient outcomes; (3) impact of treatment structure on outcomes in patients receiving methadone; (4) comparative effectiveness of different medications to treat OUD; (5) optimal educational and support structure for provision of methadone by medical providers; and (6) benefits and harms of expanded methadone access. In addition to outlining these research priorities, the task force identified important cross-cutting issues, including the impact of patient characteristics, treatment, and treatment system characteristics such as methadone formulation and dose, concurrent behavioral treatment, frequency of dispensing, urine or oral fluid testing, and methods of measuring clinical outcomes. Together, the research priorities and cross-cutting issues represent a compelling research agenda to expand access to methadone in the US.
Dynamically Exploring the QCD Matter at Finite Temperatures and Densities: A Short Review
Authors: Wu Shanjin , Shen Chun , Song Huichao
Published: October 2021

We provide a concise review on recent theory advancements towards full-fledged (3+1)D dynamical descriptions of relativistic nuclear collisions at finite baryon density. Heavy-ion collisions at different collision energies produce strongly coupled matter and probe the QCD phase transition at the crossover, critical point, and first-order phase transition regions. Dynamical frameworks provide a quantitative tool to extract properties of hot QCD matter and map fireballs to the QCD phase diagram. Outstanding challenges are highlighted when confronting current theoretical frameworks with current and forthcoming experimental measurements from the RHIC beam energy scan programs.
Unusual suppression of tungsten 5d electron depletion in superhard tungsten tetraboride solid solution with chromium under compression
Authors: Li Haijing , Gong Yu , Guo Zhiying , Dong Zheng , Liao Jiangwen , Tao Qiang , Dong Juncai , Chen Dongliang
Published: October 2021

The lattice compressibility and deformation in superhard tungsten tetraboride (WB4) solid solution with chromium (Cr) are investigated by high-pressure x-ray diffraction and x-ray absorption fine structure (XAFS) spectroscopy up to 54 GPa. In contrast to pure WB4, the c-axis softening is effectively suppressed in W0.9Cr0.1B4, and less compressibility is shown for the a- and c-axes in the entire pressure range. Meanwhile, the white-line peak of W L3-edge XAFS in W0.9Cr0.1B4 shows an absence of the sudden intensity drop as previously observed in WB4 at ∼21 GPa, suggesting a strong inhibition of W 5d electron depletion. This phenomenon is followed by an initial increase and then decrease for the W–B bond disorder, with the magnitude greatly lower than that of WB4. Besides the apparent atomic size mismatch effect, these results imply that addition of Cr, which has the same number of valence electrons as W, can introduce an unexpected electronic structure change to strengthen the W-B bond via a modification of W vacancies and B trimers distribution in WB4 lattice. Our findings point out the great significance to precise manipulation of the intrinsic W vacancies and B trimers through different solute atoms to rational optimization of WB4 hardness.
Simultaneous measurements of velocity, gas concentration, and temperature by way of thermal-anemometry-based probes
Authors: Hewes Alaïs , Mydlarski Laurent
Published: October 2021

Many natural and engineering flows transport more than one scalar. Moreover, to study the scalar mixing therein, knowledge of the velocity field is also essential. For this reason, the present work describes the development of a three-wire thermal-anemometry-based probe to simultaneously measure velocity, helium concentration, and temperature in turbulent flows. It is first demonstrated, both theoretically and experimentally, that the temperature measured by a cold-wire thermometer is effectively insensitive to helium concentration. Then, building on recent work by Hewes and Mydlarski (2021 Meas. Sci. Technol.
32 105305), which pertains to the design of interference probes (i.e. thermal-anemometry-based probes used to measure velocity and gas concentration), a novel temperature compensation technique is proposed to extend their use to non-isothermal flows. The performance of the compensation technique is validated in turbulent coaxial jets by combining the cold-wire thermometer and interference probe to form a three-wire probe. Given that the three-wire probe can be employed to obtain simultaneous measurements of velocity and multiple scalars, it can therefore be used investigate phenomena such as multi-scalar mixing, including differential diffusion.
Thermodynamic uncertainty relation for underdamped dynamics driven by time-dependent protocols
Authors: Kwon Chulan , Lee Hyun Keun
Published: October 2021

The thermodynamic uncertainty relation (TUR) for overdamped dynamics has recently been derived for general time-dependent protocols. However, its precedent TUR for underdamped dynamics has not been known yet. Even for the case of steady states, a proper way to match underdamped and overdamped TURs has not been found. We derive the TUR for underdamped systems subject to general time-dependent protocols, that covers steady states, by using the celebrating Cramér–Rao inequality. We show the resultant TUR to give rise to the inequality for the product of the variance and entropy production. We prove it to approach to the known overdamped result for large viscosity limit. It is the eventual step to pursue the TUR for Langevin systems. We present three examples to confirm our rigorous result.
Displacement Analysis Due To Time History Load Case Study Building C And D Itera
Authors: Apriwelni Siska , Yudi Ahmad , Tilameo Thio
Published: October 2021

Geologically Indonesia is located on the confluence of three major tectonic plates, namely Indo-Australia, the Eurasian plate, the Pacific plate as well as a micro-plate, namely micro-Plate Philippines. The above conditions with Indonesia being one of the countries that suffers earthquakes either tectonic or volcanic. A case study of building C and D ITERA is an adjacent building, then from that researchers want to discuss about the displacement that occurred at the confluence of the structure. The purpose of this research is to know the value of displacement i.e. inter-story drifts maximum displacement, and the junction between the building happens in the meeting structure building C and D ITERA when given dynamic load time history and to know the minimum distance between buildings so as not to occur collisions (pounding effect). Dynamic analysis for earthquake resistant building design important completed because a more accurate for evaluation against the response structure due to earthquake loads. Earthquake load (time history) used is The Loma Prieta, The Northridge, The Kobe, The Trinidad, and The Hollister has in matching with response spectrum design area of building C and D ITERA.