bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untethered rotational system with a stacked dielectric elastomer actuator
Authors: Minaminosono Ayato , Shigemune Hiroki , Murakami Taichi , Maeda Shingo 
Published: April 2021

Abstract
An untethered system can realize wide-area activities of soft robots. Herein we develop an untethered DEA wheel (UD-wheel) with a dielectric elastomer actuator (DEA). DEA is a soft actuator driven by electrostatic force. This UD-wheel is a new rotating device that integrates an untethered system and stacked DEAs. The untethered system consists of a small battery and a small high-voltage circuit. All the components are assembled seamlessly. Because the circuit can control four DEAs, the active time that the circuit continues to control the DEAs with a small battery is estimated. The estimated time matches the experimental result. We evaluated the output torque and back-drivability achieved by stacked DEAs installed in a UD-wheel. We also built a theoretical model for an in-depth evaluation. The stacking DEAs method provides a better back-drivability than the reducer method. This study suggests that our untethered rotational system may provide novel functions in soft robotics.
Removing the orientational degeneracy of the TS defect in 4H–SiC by electric fields and strain
Authors: Rühl Maximilian , Lehmeyer Johannes , Nagy Roland , Weisser Matthias , Bockstedte Michel , Krieger Michael , Weber Heiko B 
Published: April 2021

Abstract
We present a photoluminescence (PL) study of the recently discovered TS defect in 4H silicon carbide. It investigates the influence of static electric fields and local strain on the spectral properties by means of low temperature (≈4 K) ensemble measurements. Upon application of static electric fields exerted by graphene electrodes, line splitting patterns are observed, which are investigated for four different angles of the electric field with respect to the principal crystallographic axes. More detailed information can be gained when additionally the excitation polarization angle is systematically varied. Altogether, the data allow for extracting the direction of the associated electric dipole moments, revealing three distinct orientations of the underlying TS defect inside the crystal’s basal plane. We also present three so far unreported PL lines (836.7 nm, 889.7 nm, 950.0 nm) as candidates for out-of-plane oriented counterparts of the TS lines. Similar to symmetry breaking by the electric field applied, strain can reduce the local symmetry. We investigate strain-induced line splitting patterns that also yield a threefold directedness of the TS lines in accordance with the Stark effect measurements. The response to both electrical and strain fields is remarkably strong, leading to line shifts of ±12 meV of the TS1 line. Combining our findings, we can narrow down possible geometries of the TS defect.
Formation of self-organized structures in internal conductor plasma
Authors: Gondal S M , Iqbal M 
Published: April 2021

Abstract
A possibility of the confinement of two-fluid (electrons and ions) magnetized plasma in a simple cylindrical configuration as well as in a cylindrical geometry with an internal conductor is analyzed. By controlling the characteristics roots of Triple Beltrami state the formation of diamagnetic and paramagnetic structures is investigated for a simple cylindrical geometry. For an internal conductor system, the nature of relaxed structures is only paramagnetic. These paramagnetic structures are independent of the type of the characteristics roots. The results of the present investigation will be helpful to explain the equilibrium structure in the astrophysical objects such as Jupiter magnetosphere which is co-rotated with the planet and in the laboratory.
An extended version of the spin-one Duffin–Kemmer–Petiau oscillator
Authors: Chargui Y , Dhahbi A 
Published: April 2021

Abstract
We study a covariant extension of the spin-one DuffinKemmerPetiau (DKP) oscillator constructed by combining a Lorentz tensor spin–orbit coupling with the basic DKP oscillator one. We show that this model has a spin-orbit splitting controllably independent from oscillator shells and admits exact analytical solutions for both natural and unnatural parity states. The corresponding energy spectrum is then obtained for any value of the total angular momentum number and a drastic change in its structure is observed due to the additional spin–orbit coupling. In particular energy bounds and, in some cases, forbidden energy ranges are noted.
Local quantum uncertainty in a two-qubit Heisenberg spin chain with intrinsic decoherence
Authors: Guo You-neng , Peng Hu-ping , Tian Qing-long , Tan Zhi-guang , Chen Ying 
Published: April 2021

Abstract
Quantum correlation plays an important role in quantum information processing, for which various quantifiers have been proposed so far. In this paper, we address the dynamics of local quantum uncertainty (LQU) as a reliable quantifier of quantum correlation in a two-qubit Heisenberg spin chain in the presence of nonuniform external magnetic field and Dzyaloshinski-Moriya interaction with intrinsic decoherence. The influences of the initial states, external magnetic field strength, Dzyaloshinski-Moriya interaction strength and intrinsic decoherence rate on the dynamics of LQU have been in detail investigated. Our analytical results show that the dynamics of LQU is strongly depended on the form of initial states. For an initial correlated state, the dynamical behaviors of LQU exhibit either monotonic decay or damped oscillations with respect to time. While for an initial separable state, quantum correlation quantified by LQU can be created due to the Dzyaloshinski-Moriya interaction and Heisenberg anisotropic interaction. Besides, the relationship between LQU and l-norm coherence or concurrence is also demonstrated in the present model.
Transverse waves incident at the free surface of an initially stressed dissipative half-space
Authors: Selim Mahmoud M , Gepreel Khaled A 
Published: April 2021

Abstract
In this work, an attempt is done to apply Biot`s incremental deformation theory to find out the effects of initial stresses on the reflected transverse waves (S-waves) at a free surface of dissipative half-space medium. Equations of motion and its corresponding solutions are derived in lights of Biot`s theory. The impact of initial stresses and medium`s dissipation on the reflected transverse wave are studied in detail. Numerical calculations carried out using Aswan geological crustal structure and the results are presented graphically. Numerical findings reveal that, the initial stresses and the medium dissipation effects the reflection coefficients of transverse wave considerably. In addition, it has been noted that, the phase velocity decreases considerably as the initial stress parameter increases. Since the crust of the Earth, , is dissipative and initially stressed medium, thus understanding the effects of these parameters may help seismologists to get accurate results of reflected seismic transverse wave at the surface of Earth crust.
Structural and ultraviolet photo-detection properties of laser molecular beam epitaxy grown GaN layers using solid GaN and liquid Ga targets
Authors: Mauraya Amit Kumar , Mahana Debashrita , Tyagi Prashant , Ramesh Ch , Shukla Ajay Kumar , Husale Sudhir , Kushvaha Sunil Singh , Senthil Kumar Muthusamy 
Published: April 2021

Abstract
GaN epitaxial layers have been grown on sapphire (0001) substrate by laser molecular beam epitaxy technique using laser ablation of polycrystalline GaN solid and liquid Ga metal targets in the ambient of nitrogen plasma. In-situ reflection high energy electron diffraction and exsitu atomic force microscopy observations revealed that GaN growth using solid target yields rough surface under three-dimensional growth mode while a flat surface GaN is obtained using liquid Ga target. From X-ray rocking curve measurement, it is also observed that the GaN layer grown using solid GaN target has a relatively better structural quality. X-ray photoelectron spectroscopy confirmed Ga–N bond formation and near-stoichiometric composition of the GaN epilayers. The influence of threading dislocation density on the ultraviolet (UV) photoresponse properties of GaN layers have been studied using metal-semiconductor-metal (MSM) based device structure. It is found that the GaN MSM structure obtained using solid GaN target with lesser screw and dislocation densities exhibits a higher responsivity with fast response and recovery time.
High-order localized waves in the (2+1)-dimensional Ito equation
Authors: Zhang Xiaoxue , Wang Chuanjian , Zhou Yuefeng 
Published: April 2021

Abstract
In this paper, we mainly investigate the high-order localized waves in the (2+1)-dimensional Ito equation. By introducing a translation parameter and employing the Hirota derivative operator, we construct and analyze three kinds of high-order localized waves with a translation parameter: high-order line soliton, lump-type localized wave and their hybrid solutions. The obtained results show that nonlinear localized waves with a translation parameter have more plentiful dynamical behaviors. It is shown that the plus and minus resonance phenomena of two line solitons can be controlled by a translation parameter. The direction of propagation and symmetry characteristics of lump-type localized wave can be also governed by this translation parameter. Through analyzing the time delay effect we finally discuss and demonstrate the absorb-emit and emit-absorb interactions between a line soliton and a lump-type localized wave.
Thermo-bioconvection transport of nanofluid over an inclined stretching cylinder with Cattaneo–Christov double-diffusion
Authors: Waqas Hassan , Manzoor Umair , Muhammad Taseer , Hussain Sajjad 
Published: April 2021

Abstract
In this paper, Newtonian nanofluid flow is observed under the effects of the magnetic field, activation energy and motile microorganisms over an inclined stretchable cylinder. The magnificent aspects of nanoliquid are demonstrated by enduring the Brownian motion and thermophoresis diffusion features. Nonlinear higher order partial differential equations are transformed into first-order ordinary differential equations with suitable similarity variables. The attained sets of governing equations are then cracked by bvp4c procedure in MATLAB mathematical software. The numerical and graphical outcomes of controlling parameters such as Prandtl number, mixed convection, activation energy, thermophoresis, Brownian parameter, Biot number, Lewis number, Peclet number and motile concentration parameter against the velocity, temperature, volumetric concentration and motile concentration of nanoparticles of the fluid are discussed. The velocity is enhanced with the growth valuation in mixed convection and decay by rising variation of buoyancy ratio parameter, magnetic parameter and bio-convective Rayleigh parameter. The evolution in motile microorganisms is due to the increasing values of microorganisms Biot number. The presented data can be helpful in enhancement of manufacturing processes, biomolecules, extrusion systems applications and energy production improvement.
Effects of electric fields on 7Be half-life
Authors: Gholamian Farshid , Firoozabadi Mohammad Mehdi , Sarhaddi Reza 
Published: April 2021

Abstract
First-principle calculations based on the density functional theory (DFT) method are adopted to investigate the influence of a strong electric field on the 7Be half-life. Accordingly, electronic structures of Be and BeO are examined in the presence of a homogeneous electric field. The electron density at the nucleus is estimated upon the geometry optimization. Our computations for the Be metal indicate a 0.02% increase in the decay rate of the 7Be nucleus, corresponding to a 0.02% decrease in the 7Be half-life, both at 5.14 V/Å (0.1 a.u.). Furthermore, it is determined that the decay rate of 7Be is not considerably altered up to 3.6 V/Å in the BeO structure. Our results show that the screening energy of the electron can be dependent on the applied electric field strength. Furthermore, we predict variations in the Coulomb potential at the 7Be nucleus due to electric field application.
Consolidation of memory traces in cultured cortical networks requires low cholinergic tone, synchronized activity and high network excitability
Authors: Dias Inês , Levers Marloes R , Lamberti Martina , Hassink Gerco C , van Wezel Richard , le Feber Joost 
Published: April 2021

Abstract
In systems consolidation, encoded memories are replayed by the hippocampus during slow-wave sleep (SWS), and permanently stored in the neocortex. Declarative memory consolidation is believed to benefit from the oscillatory rhythms and low cholinergic tone observed in this sleep stage, but underlying mechanisms remain unclear. To clarify the role of cholinergic modulation and synchronized activity in memory consolidation, we applied repeated electrical stimulation in mature cultures of dissociated rat cortical neurons with high or low cholinergic tone, mimicking the cue replay observed during systems consolidation under distinct cholinergic concentrations. In the absence of cholinergic input, these cultures display activity patterns hallmarked by network bursts, synchronized events reminiscent of the low frequency oscillations observed during SWS. They display stable activity and connectivity, which mutually interact and achieve an equilibrium. Electrical stimulation reforms the equilibrium to include the stimulus response, a phenomenon interpreted as memory trace formation. Without cholinergic input, activity was burst-dominated. First application of a stimulus induced significant connectivity changes, while subsequent repetition no longer affected connectivity. Presenting a second stimulus at a different electrode had the same effect, whereas returning to the initial stimuli did not induce further connectivity alterations, indicating that the second stimulus did not erase the ‘memory trace’ of the first. Distinctively, cultures with high cholinergic tone displayed reduced network excitability and dispersed firing, and electrical stimulation did not induce significant connectivity changes. We conclude that low cholinergic tone facilitates memory formation and consolidation, possibly through enhanced network excitability. Network bursts or SWS oscillations may merely reflect high network excitability.
Examination of stiff ion temperature gradient mode physics in simulations of DIII-D H-mode transport
Authors: Holland C. , Luce T.C. , Grierson B.A. , Smith S.P. , Marinoni A. , Burrell K.H. , Petty C.C. , Bass E.M. 
Published: April 2021

Abstract
A systematic evaluation of gyrokinetic and gyrofluid model predictions of ion temperature gradient (ITG) stability and transport using parameters from DIII-D high confinement mode (H-mode) plasmas has been performed. The nonlinear CGYRO code is used to make the gyrokinetic predictions, and the quasilinear TGLF model for the corresponding gyrofluid predictions. The assessments are made at three radii (normalized toroidal flux ρ
tor = 0.4, 0.55, and 0.7) in three different plasma scenarios with varying levels of neutral beam heating and torque. For each of the nine cases (3 radii × 3 scenarios) considered, ITG turbulence is found to be the dominant long-wavelength instability and transport mechanism. The inclusions of both transverse magnetic fluctuations and dynamic fast beam ions are stabilizing for all cases considered, with strongest effects seen at ρ
or = 0.4 where the fast ion population and normalized plasma pressure β = 2μ
0
nT/B
2 are highest. The further inclusion of parallel magnetic fluctuations does not have a meaningful impact on the ITG turbulence in these scenarios, but does destabilize (in combination with fast ions) new high-frequency instabilities at ρ
tor = 0.4 in the high power scenarios. In each case the linear and nonlinear ITG critical gradients are predicted to be lower than the measured ITG scale lengths and their associated uncertainties. Inclusion of equilibrium flow shear in the transport predictions generally leads to an upshift in effective critical gradient rather than a qualitative change in the predicted stiffness, with stronger responses typically seen in the gyrokinetic predictions than in the gyrofluid results. However, in most cases these upshifted gradients still remain below the measured values and their uncertainties. Although the predicted critical gradients are below the measured gradients, both models predicted flux-matching gradients consistent with measured values in six of the nine cases considered, with no clear systematic over- or underprediction. Thus, while the experimental ion temperature profiles do not appear to be closely pinned to the ITG critical gradient, both gyrokinetic and gyrofluid models are able to accurately match the measured gradients reasonably well in most cases.
Material migration in W and Mo during bubble growth and fuzz formation
Authors: Patino M.I. , Nishijima D. , Tokitani M. , Nagata D. , Yu J.H. , Doerner R.P. 
Published: April 2021

Abstract
Growth of helium (He) induced bubbles and fuzz in tungsten (W) and molybdenum (Mo) is investigated using samples of W films on Mo substrates and Mo films on W substrates exposed to He-containing plasma in the temperature range of 340 to 1075 K, fluence range of 1.0–14 × 1025 He·m−2, and incident ion energy of <50 eV. No fuzz (only up to 2 nm diameter bubbles) and no material transport occur in W films at ⩽750 K, while precursors-of or fully-developed fuzz and material mixing occur in W and Mo films at ⩾800 K. This suggests that fuzz forms in multi-material systems as long as one material meets the conditions for fuzz formation, namely T
s/T
m ∼ 0.27–0.5 where T
s and T
m are the sample exposure and material melting temperatures, respectively. Larger He bubbles, more material mixing, and further-developed fuzz occur at higher temperature due to increased mobility of He atoms and small He clusters. Accumulation of substrate material at the surface of fuzzy W and Mo thin-film (<80 nm) samples suggests fuzz growth by material transport from the bubble layer in the bulk up to the fiber tip, likely by a two-step process: (i) diffusion of punched dislocation loops in the bulk toward the fuzz base and (ii) diffusion of adatoms along the fuzz base and fiber surface (with effective transport of adatoms upwards due to trapping of adatoms at curved surfaces of fiber tips and/or due to the continuous generation of adatoms at the fuzz base). While the bubble size and fuzz thickness increase with reduced W concentration in Mo thin-film samples at 838 K likely due to an increase in trap mutation and dislocation loop punching in Mo compared to W, the fuzz thickness decreases with reduced W concentration at 1075 K despite an increase in the bubble size likely due to slower diffusion of interstitial loops in Mo.
The EEE Multigap Resistive Plate Chambers as tracking devices to monitor the stability of a civil building
Authors: Pinto C. , Abbrescia M. , Avanzini C. , Baldini L. , Baldini Ferroli R. , Batignani L.G. , Battaglieri M. , Boi S. , Bossini E. , Carnesecchi F. , Cicalò C. , Cifarelli L. , Coccetti F. , Coccia E. , Corvaglia A. , De Gruttola D. , De Pasquale S. , Fabbri L. , Galante L. , Galeotti P. , Garbini M. , Gemme G. , Gnesi I. , Grazzi S. , Hatzifotiadou D. , La Rocca P. , Liu Z. , Mandaglio G. , Maron G. , Mazziotta M.N. , Mulliri A. , Nania R. , Noferini F. , Nozzoli F. , Palmonari F. , Panareo M. , Panetta M.P. , Paoletti R. , Pellegrino C. , Perasso L. , Piragino G. , Pisano S. , Riggi F. , Righini G.C. , Ripoli C. , Rizzi M. , Sartorelli G. , Scapparone E. , Schioppa M. , Scribano A. , Selvi M. , Serri G. , Squarcia S. , Taiuti M. , Terreni G. , Trifiró A. , Trimarchi M. , Vistoli M.C. , Votano L. , Williams M.C.S. , Zichichi A. , Zuyeuski R. 
Published: April 2021

Abstract
Due to their efficiency, tracking capabilities and long-term
operational conditions, Multigap Resistive Plate Chambers (MRPC) may
be used in a stable location in coincidence with additional
detectors fixed to other parts of a civil building, to detect
relative displacements of different parts of the building due to
long term deformations of the structure. In this contribution we
report the results of two different measurements carried out in the
Department of Physics and Astronomy of the University of Catania
(with three floors above the ground and an underground basement),
using one of the MRPC telescopes of the Extreme Energy Events
project, in coincidence with two scintillator-based muon telescopes
located in various positions inside the building. Experimental
results obtained by these measurements campaigns over a period of
about three months are reported, together with a discussion about
the performance of the technique. The sensitivity of the method is
also discussed by means of Monte Carlo simulations.
Gas mixture quality studies for the CMS RPC detectors during LHC Run 2
Authors: Gelmi A. , Guida R. , Mandelli B. 
Published: April 2021

Abstract
Resistive Plate Chamber (RPC) detectors are widely employed in the muon trigger systems of three experiments at the CERN Large Hadron Collider (LHC). They are operated with gas mixture recirculation systems to reduce operational costs and greenhouse gas emissions since their gas mixture is based on C2H2F4, which has a high global warning potential. It is well known that the C2H2F4 molecule can break down under the effect of radiation and electric field. This leads to the creation of several impurities and free fluoride ions (F-), which could accumulate under gas recirculation and potentially attach to the RPC bakelite electrode inner surface. For these reasons, an extensive gas analysis campaign has been performed during LHC Run 2 for the CMS RPC system to verify gas mixture quality and possible accumulation of impurities.
During the entire LHC Run 2 period, a gas chromatograph has been used to analyze the RPC gas mixture at different points of the gas system: quality of pure C2H2F4, fresh gas from the mixer, gas at the output of the detectors, and after the purifier module. Several impurities have been found and identified. Few impurities are already present in the C2H2F4 supply, as residuals of the industrial production. Nevertheless, it was found that some of these impurities, as well as others, are created inside the detector gas gap due to the fragmentation of the C2H2F4 molecule under the effects of electric field and radiation.
During the 2018 LHC Run several gas analysis points were added to measure the fluoride ions production in different sectors of the RPC detector system. Indeed the products of the C2H2F4 fragmentation do not always recombine and F- species can stay free in the gas mixture. F- analyses were performed on the gas at the output of the detectors both for barrel and endcap regions, where radiation levels and operational conditions were different. In this way, it was possible to correlate the F- production with integrated charge, and gas mixture flow rate. In parallel, the RPC currents have been constantly monitored to look for possible correlations.
Fluoride measurements have also been performed at GIF++ to better understand the correlation between F- production, radiation levels and gas volume exchanges.
A comprehensive overview of the results obtained from the different types of gas analyses and possible correlation with RPC currents and LHC luminosity will be presented.