bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leaf inclination angle and foliage clumping in an evergreen broadleaf
Authors: Pisek Jan , Řezníčková Ladislava , Adamson Kairi , Ellsworth David S. 
Published: October 2021

How leaves are presented affects interaction of atmospheric CO2, energy (light), and plant physiology. Plant productivity is primarily determined by the amount of leaf area, leaf orientation and distribution in space. Not much attention has been paid to possible changes in leaf orientation and distribution with elevated CO2, but its effect on plant growth could alter the proportions of sunlit and shaded leaf areas and feedback on carbohydrate available for further growth. We report on first measurements of leaf inclination angle distribution and foliage clumping in a native evergreen Eucalyptus woodland in ambient CO2 and under +150 ppm elevated CO2. We found that a spherical leaf angle distribution was not an appropriate supposition for present species (Eucalyptus tereticornis Sm.) at this site. Our measurements of leaf inclination angles from imagery indicated an erectophile, highly skewed unimodal leaf inclination angle distribution function. We conclude that despite the measured steeper angles under elevated CO2 concentrations, the leaf angle change is not significant and falls within the expected natural variability and uncertainties connected with the measurement method. The lack of a clear response of leaf orientation and foliage clumping to elevated CO2 concentration indicates that the previously produced datasets of leaf inclination angles and foliage clumping maps with Earth observation data may be suitable while modelling carbon and water cycles under climate change.
Cochlear outer hair cell electromotility enhances organ of Corti motion on a cycle-by-cycle basis at high frequencies in vivo
Authors: Dewey James B. , Altoè Alessandro , Shera Christopher A. , Applegate Brian E. , Oghalai John S. 
Published: October 2021

Significance
The remarkable high-frequency sensitivity of mammalian hearing depends on the amplification of sound-evoked cochlear vibrations by outer hair cells. One way that outer hair cells are proposed to generate amplifying forces is through voltage-driven changes in cell length. However, it remains unclear whether this electromotility can work fast enough in vivo to provide amplification at the necessary frequencies. Here, we show that sound elicits motions within the living mouse cochlea that are fully consistent with electromotility. These motions are large relative to the motion of the underlying cochlear partition, including at high frequencies. The data therefore suggest that electromotility can indeed provide high-speed amplification in vivo.
Testing models at the neural level reveals how the brain computes subjective value
Authors: Williams Tony B. , Burke Christopher J. , Nebe Stephan , Preuschoff Kerstin , Fehr Ernst , Tobler Philippe N. 
Published: October 2021

Significance
In recent years, models have played an increasingly important role for understanding the brain in cognitive, behavioral, and systems neuroscience. Decision neuroscience in particular has benefitted greatly from the application of economic models of choice preferences to neural data. However, an often-overlooked aspect is that many models of preferences have a generic problem—they make extremely similar behavioral predictions. Here, we demonstrate that to understand the mechanisms of valuation in the brain, it is useful to compare models of choice preferences not only at the behavioral but also at the neural level.
Dendrite tapering actuates a self-organizing signaling circuit for stochastic filopodia initiation in neurons
Authors: Mancinelli Gloria , Lamparter Lucas , Nosov Georgii , Saha Tanumoy , Pawluchin Anna , Kurre Rainer , Rasch Christiane , Ebrahimkutty Mirsana , Klingauf Jürgen , Galic Milos 
Published: October 2021

Significance
Cellular signaling pathways respond to a wide range of stimuli. How signaling circuits are activated without an instructive stimulus and what this is good for are less clear. Combining theoretical and experimental approaches, we show that curvature-sensing proteins stabilize stochastic membrane deformations to nucleate a self-organizing actin-regulatory signaling circuit. In neurons, these signaling hubs control the initiation of exploratory filopodia that sample the cell vicinity for appropriate synaptic partners. The extent and diversity of proteins capable of forming self-organizing circuits at stochastically deformed membranes indicates a general signaling mechanism.
NAP-XPS as a new tool for in-situ studies of SMOX gas sensors
Authors: Junker Benjamin , Favaro Marco , Starr David E , Hävecker Michael , Weimar Udo , Barsan Nicolae 
Published: October 2021

Abstract
The development of near ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) allows scientists to perform spectroscopic investigations of solid–gas interfaces at elevated pressures in a defined gas atmosphere. Due to the high surface sensitivity and element specificity, this technique promises to be a valuable and powerful tool in gas sensor research. A Pt doped SnO2 sample was studied to explore a variety of phenomena in sensor research that can be addressed using NAP-XPS at a synchrotron. The change of several parameters, including chemical shifts, band bending, and valence band structure, could be observed in-situ and highlights the enormous potential of the method in this field. Furthermore, a series of DC resistance measurements has been performed to study the impact of pressure. The decrease of resistance at low pressure strongly indicates that both the electronic characteristics as well as the surface composition under the conditions of NAP-XPS are dissimilar to operando conditions at atmospheric pressure.
Radiation exposure in the intra-arterial nimodipine therapy of subarachnoid hemorrhage related cerebral vasospasm
Authors: Opitz Marcel , Zensen Sebastian , Bos Denise , Wetter Axel , Kleinschnitz Christoph , Uslar Ellen , Jabbarli Ramazan , Sure Ulrich , Radbruch Alexander , Li Yan , Dörner Nils , Forsting Michael , Deuschl Cornelius , Guberina Nika 
Published: October 2021

Abstract
The selective intra-arterial nimodipine application for the treatment of cerebral vasospasm (CVS) in patients after spontaneous subarachnoid hemorrhage (sSAH) is widely employed. The purpose of this study is to examine the radiation exposure and to determine local diagnostic reference levels (DRLs) of intra-arterial nimodipine therapy. In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients undergoing (I) selective intra-arterial nimodipine application or (II) additional mechanical angioplasty for CVS treatment. Interventional procedures were differentiated according to the type of procedure and the number of probed vessels. Altogether 494 neurointerventional procedures of 121 patients with CVS due to sSAH could be included. The radiation exposure indices were distributed as follows: (I) DRL 74.3 Gy·cm2, AD 59.8 Gy·cm2; (II) DRL 128.3 Gy·cm2, AD 94.5 Gy·cm2. Kruskal–Wallis test confirmed significant dose difference considering the number of probed vessels (p< 0.001). The mean cumulative dose per patient was 254.9 Gy·cm2 (interquartile range 88.6–315.6 Gy·cm2). The DRLs of intra-arterial nimodipine therapy are substantially lower compared with DRLs proposed for other therapeutic interventions, such as thrombectomy or aneurysm coiling. However, repeated therapy sessions are often required, bearing the potential risk of a cumulatively higher radiation exposure.
Prediction of damage mechanisms of cross-ply composite materials using novel non-linear multiscale methodologies
Authors: Tsivolas Eleftherios , Gergidis Leonidas N , Paipetis Alkiviadis S 
Published: October 2021

Abstract
In the present work, a novel multiscale material methodology is applied to a finite element mesh of a cross-ply composite material in tension in order to study the progressive damage and failure of the material at multiple scales by combining damage evolution models and failure criteria in microscale and cohesive zone modeling in macroscale. The micromechanics user material (Umat) developed follows a nonlinear version of the Mori–Tanaka theory and is coupled with mesoscale damage model. The concept of this user material is to dehomogenize-localize the strain tensor at each integration point for each time increment using Eshelby’s theories and strain concentration tensors. This material implementation allows the researcher to analyze results at two scales in the post processing stage, both for the composite material and the constituents for each time increment. It is observed that in the multiscale model the results are closer to the experimental measurements and even more damage mechanisms can be predicted, such as matrix damage and fiber failure. The developed multiscale methodology is advantageous since the constituents can follow different material models, with many failure criteria. It is also capable of predicting stresses, strains, plastic strains and more analysis variables not only in the macroscale-homogeneous level but also in microscale constituent-wise level.
Macroscopic plasma analysis from 1D-radial kinetic results of a Hall thruster discharge
Authors: Marín-Cebrián Alberto , Domínguez-Vázquez Adrián , Fajardo Pablo , Ahedo Eduardo 
Published: October 2021

Abstract
A radial particle-in-cell model of the weakly-collisional plasma discharge in a Hall thruster, provides the non-Maxwellian velocity distribution functions (VDF) of ions and electrons. The model considers a radial magnetic field, secondary electron emission from the two walls, and phenomenological models of anomalous electron scattering. The electron VDF is used to assess the different terms in the macroscopic momentum and energy equations, identifying those differing from the standard fluid model for a near-Maxwellian VDF. The pressure tensor consists of an anisotropic gyrotropic part and a small gyroviscous part. Nonetheless, the gradient of this last one affects the cross-field electron current density, generating radial undulations that resemble those reported for near-wall conductivity. A gyroviscous energy flux is identified too. The heat flux parallel to the magnetic lines does not follow a conductive-type law but a convective-type one, already found in other weakly-collisional plasmas. The tails of the electron velocity distribution function are partially depleted due to wall collection, leading to reduced electron fluxes of particles and energy, which are characterized with parameters useful for fluid models. Differences in the plasma response for annular and planar channel geometries are highlighted. The levels of replenishment of the electron VDF and of the asymmetries in radial profiles differ for isotropic and anisotropic anomalous scattering models.
Resonant states and their role in nanophotonics
Authors: Both S , Weiss T 
Published: October 2021

Abstract
Resonant phenomena have been extensively used in micro- and nanophotonics. Mathematically, these phenomena originate in a discrete set of basis functions known as resonant states or quasi-normal modes. Therefore, it is extremely beneficial to develop theoretical approaches that use these resonant states as a physically meaningful basis in order to describe the light–matter interaction in micro- and nanoresonators. However, the question of how to normalize resonant states correctly for such an expansion initially hampered many theoretical attempts. Only recently, this problem of normalization has been solved via different approaches, providing a completely rigorous basis for not only explaining but also quantifying a large variety of resonant phenomena. This review article provides an overview of the related activities in the field and typical applications. We compare the different approaches with a focus on formulations via the Mittag-Leffler expansion of the Green’s dyadic on the complex frequency plane and an analytic normalization scheme for the resonant states. Specifically, we discuss the pole expansion of the near and far field and outline related theoretical tools such as the resonant-state expansion and first-order perturbation theories. These approaches allow for efficiently describing light–matter interaction between local emitters and resonators, scattering of light at nanoparticles, and resonantly-enhanced optical sensing. Moreover, the resulting equations provide insight into the underlying physical mechanisms, which can be used to tailor the light–matter interaction and to predict new phenomena such as the recently observed complex-valued mode volumes. Since the Mittag-Leffler theorem is valid beyond the continuation of physical quantities to the complex frequency plane, an introduction to alternative modal approaches, namely those based on permittivity eigenmodes and propagating modes, is included here as well. While the link of these approaches to resonant phenomena is less obvious, they can be advantageous in some cases. Finally, we show that modal theories can be even applied in nonlinear optics. Hence, the theory of resonant states provides a general theoretical framework in micro- and nanophotonics.
Piezoelectric stick-slip actuator integrated with ultrasonic vibrator for improving comprehensive output performance
Authors: Yang Shitong , Li Yuelong , Qiao Guangda , Ning Peng , Lu Xiaohui , Cheng Tinghai 
Published: October 2021

Abstract
In this paper, a novel compact piezoelectric stick-slip actuator integrated with ultrasonic vibrator based on ultrasonic anti-friction effect is proposed. Based on inverse piezoelectric effect, the piezoelectric stack generates the axial vibration under the excitation of asymmetric sawtooth wave, the ultrasonic vibrator is composed of a brass block and four piezoelectric plates, which is used to excite the ultrasonic longitudinal vibration mode in the fast deformation phase of piezoelectric stack. Due to ultrasonic anti-friction effect, the backward displacement of the actuator is effectively suppressed, and the bidirectional comprehensive output performance is improved. The prototype is fabricated and the operating principle of hybrid excitation is introduced, then the frequency of the first-order longitudinal vibration mode is explored by finite element analysis and impedance test, and the systematic experimental test is conducted. The test results show that when the sawtooth frequency is 300 Hz, comparing with the traditional sawtooth excitation mode, the proposed hybrid excitation mode can improve the velocities of the forward and backward directions by 30% and 26.7%, and the bidirectional maximum vertical mass loads are increased by 44.4% and 50%. This work provides a design concept that uses ultrasonic vibrator to improve the bidirectional comprehensive output performance of the piezoelectric stick-slip actuator.
Evaluation of electrical fatigue limits in REBCO coated conductor tapes through static fatigue testing at 77 K
Authors: de Leon Michael B , Nisay Arman Ray , Shin Hyung-Seop 
Published: October 2021

Abstract
Significant development has been made toward guaranteeing the performance of high-temperature superconducting (RE)Ba2Cu3O7−x
coated conductor (CC) tapes in superconducting devices such as high-field magnets and coils. To understand the superconducting behaviors of CC tapes used in such devices under various mechanical- and thermal-induced loads, their mechanical and electromechanical properties should be evaluated in consideration of their application environments. Under static or cyclic fatigue loads, critical current (I
c) can degrade as a result of damage to the superconducting layer, even under loads that do not exceed the irreversible stress limits for I
c degradation (σ
irr). Therefore, prediction of the stress level that can degrade I
c under various conditions, such as the endurance limit (stress), is significant for actual coil or magnet applications of CC tapes. A static fatigue tester for CC tapes at 77 K was used in this study to apply a static fatigue load to a 12 mm wide GdBa2Cu3O7−x
CC tape specimen under simultaneous axial tension and bending stresses in a U-shaped configuration. Bending mandrels were used to superimpose various bending strains onto the applied static axial tensile strain, and I
c across various voltage tap separations was measured over time, up to 100 h. The electrical static fatigue strength and endurance limit for I
c degradation were determined based on the 95% I
c retention criterion and 100 h of elapsed time, respectively. Results show that bending strain, dependent on mandrel diameter, can greatly influence I
c degradation behaviors and that I
c can drop considerably in the bent sections compared to the straight sections over time. Analyses of the combined strains in the bent sections allowed the prediction of diameter-dependent electrical static endurance limits under subcritical crack growth. The CC tape’s electrical static endurance limit was greatly affected at smaller bending diameters. When CC coils with diameters smaller than or equal to 50 mm are made using 12 mm wide CC tapes, the electrical static endurance limit is low, roughly ⩽0.63σ
irr.
Study of internal porous structure formation of the powder metallurgically prepared aluminium foam
Authors: Gopinathan A , Jerz J , Kováčik J , Dvorák T , Orovčík L 
Published: October 2021

Abstract
The internal pore wall structure formation and density play an important role in improving the mechanical and thermal properties of the closed-cell aluminium foams. The present research work aims to investigate the internal structure formation of the aluminium foam prepared by powder metallurgy and the uniformity of the distribution of the pores when the minimum amount of TiH2 is added. The foamable precursor of two different aluminium alloys (Al-1050 and A5083) is produced with a TiH2 gaseous agent of 0.05 wt.%. The parameters analysed include the density, pore wall formations, pore, and metal density distribution inside the structure with the help of X-ray tomography. Furthermore, the image-processing technique has been adopted to produce the 3D surrogate model of the foam for visual inspection and analysis. The obtained results show the importance of the amount of TiH2 addition and of the foaming furnace temperature in deciding the internal porous structure formation. Further, the pore morphology of lower porosity foams (in the range of 30-40 % porosity) of the two alloys produced at 690 °C furnace temperature is investigated with the help of developed surrogate models. The presence of micropores and uniformity of the distribution of pores found brings the idea of choosing the optimized structure of foam for thermal energy storage systems associated with PCM.
Influence on mechanical behaviors considering construction hosting process of large-scale steel structure
Authors: Fu Y D , Yang S , Li G , Lin X L , Zhang H D , Shang K G 
Published: October 2021

Abstract
In the design of large-scale steel structure, the design calculation of the structure is usually based on the service state. But in the process of steel structure construction, the displacement and stress produced in the construction process cannot be completely consistent with that in the design state. With the progress of construction process, the deformation and stress caused by self-weight and construction load gradually accumulate until the structure is formed, which will produce construction error relative to the design state. In this paper, FEM method was used to simulate the construction process of the steel grid roof of the theater in the Beijing Sub Center Theater project, and the influence of the accumulated deformation and stress on the mechanical properties of the structure during the construction process was analyzed. The results show that the cumulative deformation and stress in the construction process have a great influence on the final deformation and stress distribution of the structure. The maximum vertical displacement in the actual construction state is 599.6% of that in the design state, and the maximum stress is 119.7% of that in the design state. This will lead to the difference between the construction-completed structure and the design structure, which makes the design result dangerous. The measures to optimize the construction process were also given in this paper, which provides guidance for the construction process of large-scale steel structure.
Technoeconomic analysis of High Temperature Reactors for industrial applications in Poland
Authors: Chmielarz B , Bredimas A , Herpson C 
Published: October 2021

Abstract
The paper analyses Polish industrial energy market requirements and the economic boundary conditions of for High Temperature Reactor (HTR)-based hybrid energy systems for electricity, heat, and hydrogen production. The Polish industry suffers from high imported gas prices and high dependence on domestic coal sector. Most industrial coal boilers are ageing and will need replacement within two decades. Increasing emission prices will soon cripple the profitability of coal in favour of natural gas and leave an opening for HTRs. HTRs can be competitive for both heat and electricity generation if used at load factors above 90% and constructed within budget and on time. The competitiveness of HTRs grows further with rising fossil fuels and CO2 emission prices. For industrial hydrogen, steam methane reforming (SMR) is competitive against any other alternative. Large-scale hydrogen production with HTR-based Sulphur Iodine cycle may compete with SMR if capital and operational costs can be decreased. High temperature steam electrolysis requires more durable materials and lower capital cost. Electrolysis, given its relatively low CAPEX and scalability, can be competitive when electricity is cheap as a result of over-production from intermittent power capacities. Other fossil-based hydrogen production methods appear more costly and CO2-intensive than SMR. The study was done as a part of the GEMINI+ project.