bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identifying time-varying dynamics of heart rate and oxygen uptake from single ramp incremental running tests
Authors: Gielen Jasper , Stessens Loes , Meeusen Romain , Aerts Jean-Marie 
Published: June 2024

Abstract

Objective. The fact that ramp incremental exercise yields quasi-linear responses for pulmonary oxygen uptake (

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) and heart rate (HR) seems contradictory to the well-known non-linear behavior of underlying physiological processes. Prior research highlights this issue and demonstrates how a balancing of system gain and response time parameters causes linear

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responses during ramp tests. This study builds upon this knowledge and extracts the time-varying dynamics directly from HR and

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data of single ramp incremental running tests. Approach. A large-scale open access dataset of 735 ramp incremental running tests is analyzed. The dynamics are obtained by means of 1st order autoregressive and exogenous models with time-variant parameters. This allows for the estimates of time constant (τ) and steady state gain (SSG) to vary with work rate. Main results. As the work rate increases, τ-values increase on average from 38 to 132 s for HR, and from 27 to 35 s for

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. Both increases are statistically significant (p < 0.01). Further, SSG-values decrease on average from 14 to 9 bpm (km·h−1)−1 for HR, and from 218 to 144 ml·min−1 for

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(p < 0.01 for decrease parameters of HR and

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). The results of this modeling approach are line with literature reporting on cardiorespiratory dynamics obtained using standard procedures. Significance. We show that time-variant modeling is able to determine the time-varying dynamics HR and

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responses to ramp incremental running directly from individual tests. The proposed method allows for gaining insights into the cardiorespiratory response characteristics when no repeated measurements are available.
Role of anisotropy in understanding the molecular grounds for density scaling in dynamics of glass-forming liquids
Authors: Grzybowski A , Koperwas K , Paluch M 
Published: June 2024

Abstract
Molecular Dynamics (MD) simulations of glass-forming liquids play a pivotal role in uncovering the molecular nature of the liquid vitrification process. In particular, much focus was given to elucidating the interplay between the character of intermolecular potential and molecular dynamics behaviour. This has been tried to achieve by simulating the spherical particles interacting via isotropic potential. However, when simulation and experimental data are analysed in the same way by using the density scaling approaches, serious inconsistency is revealed between them. Similar scaling exponent values are determined by analysing the relaxation times and pVT data obtained from computer simulations. In contrast, these values differ significantly when the same analysis is carried out in the case of experimental data. As discussed thoroughly herein, the coherence between results of simulation and experiment can be achieved if anisotropy of intermolecular interactions is introduced to MD simulations. In practice, it has been realized in two different ways: (1) by using the anisotropic potential of the Gay–Berne type or (2) by replacing the spherical particles with quasi-real polyatomic anisotropic molecules interacting through isotropic Lenard–Jones potential. In particular, the last strategy has the potential to be used to explore the relationship between molecular architecture and molecular dynamics behaviour. Finally, we hope that the results presented in this review will also encourage others to explore how ‘anisotropy’ affects remaining aspects related to liquid–glass transition, like heterogeneity, glass transition temperature, glass forming ability, etc.
Improving the superconducting properties of 100 m class MgB2 wire with 18+1 filaments produced via an internal Mg diffusion process
Authors: Wang Zhikai , Yang Fang , Wang Qingyang , Wang Dayou , Yan Guo , Zhang Pingxiang 
Published: June 2024

Abstract
Internal Mg diffusion (IMD) technology reveals the expansive prospects of MgB2 superconducting wires. To facilitate the practical application of IMD, a series of 100 m class MgB2 wires with 18 + 1 filaments were prepared in this study. Based on the optical micrographs and performance analyses, the annealing temperature, B powder type and diameter of wires were refined. The results indicated that introducing C-coated B powder into wires would accelerate the diffusion of Mg melt and enhance the J
e and layer J
c significantly, while shrinking the wire diameter would further improve the wire transport capability. The optimal J
e and layer J
c of wire with an 0.8 mm diameter reached 1.2 × 104 and 1.1 × 105 A cm−2, respectively at 4.2 K and 8 T, which contained C-coated B powder and was annealed at 650 °C. These improved wires were eligible for magnet use in terms of performances, integrity, length and uniformity.
Investigation on characteristic of vanadium trioxide insulation mixed with metal powder for rare-earth barium copper oxide coils
Authors: Lee Sung Hoon , Chae Yoon Seok , Kim Ho Min , Quach Huu Luong , Kim Ji Hyung 
Published: June 2024

Abstract
This study examined the turn-to-turn contact resistance (R
ct) between rare-earth barium copper oxide (REBCO) tapes and layers of vanadium trioxide (V2O3) and V2O3 mixed with metal powder mixture. V2O3 in single crystal structure was electrically characterised to exhibit resistivity with negative temperature dependence, allowing the turn-to-turn insulation to self-regulate the current bypass between REBCO tapes. To facilitate effective quench protection of V2O3-insulated REBCO magnets above the metal-insulator transition temperature (T
rt), R
ct must be further reduced to a level similar to those of non- and metal as insulated (NI and MI) REBCO magnets. Thus, we explored the mixing of conductive metal powders such as molybdenum (Mo) with V2O3 paste and investigated the transition properties of R
ct. The resistance versus temperature characteristics, microscopic morphologies of the V2O3 layers, and thermal conductivity (k
v) were appropriately assessed to determine the effects of mixing the metal powder with V2O3. The R
ct of virgin V2O3 exhibited variations of 107–105
μΩ cm2 under 77–293 K. As the mixing concentration of the metal powder was increased, the reduction magnitude on R
ct increased for > T
rt (approximately 150 K). Furthermore, the transition slope became gentler for a wider temperature range of < T
rt. For metal powder concentrations exceeding 50 wt%, R
ct decreased by approximately 2 orders of magnitude (∼103
μΩ cm2) for > 150 K compared with that for virgin V2O3 paste. Moreover, compared to that of pure V2O3, k
v demonstrated a remarkable increase of approximately 352% at 91 K for Mo powder mixed at a concentration of 60 wt%. The improved electrical and thermal properties of the V2O3 insulation layer owing to the mixing of metal powders can help REBCO magnets operate in an insulated state under normal conditions and effectively convert to a non-insulated state under quenching.
Pattern selection and the route to turbulence in incompressible polar active fluids
Authors: Reinken Henning , Heidenreich Sebastian , Bär Markus , Klapp Sabine H L 
Published: June 2024

Abstract
Active fluids, such as suspensions of microswimmers, are well known to self-organize into complex spatio-temporal flow patterns. An intriguing example is mesoscale turbulence, a state of dynamic vortex structures exhibiting a characteristic length scale. Here, we employ a minimal model for the effective microswimmer velocity field to explore how the turbulent state develops from regular, stationary vortex patterns when the strength of activity resp. related parameters such as nonlinear advection or polar alignment strength—is increased. First, we demonstrate analytically that the system, without any spatial constraints, develops a stationary square vortex lattice in the absence of nonlinear advection. Subsequently, we perform an extended stability analysis of this nonuniform ‘ground state’ and uncover a linear instability, which follows from the mutual excitement and simultaneous growth of multiple perturbative modes. This extended analysis is based on linearization around an approximation of the analytical vortex lattice solution and allows us to calculate a critical advection or alignment strength, above which the square vortex lattice becomes unstable. Above these critical values, the vortex lattice develops into mesoscale turbulence in numerical simulations. Utilizing the numerical approach, we uncover an extended region of hysteresis where both patterns are possible depending on the initial condition. Here, we find that turbulence persists below the instability of the vortex lattice. We further determine the stability of square vortex patterns as a function of their wavenumber and represent the results analogous to the well-known Busse balloons known from classical pattern-forming systems such as Rayleigh–Bénard convection experiments and corresponding models such as the Swift–Hohenberg equation. Here, the region of stable periodic patterns shrinks and eventually disappears with increasing activity parameters. Our results show that the strength of activity plays a similar role for active turbulence as the Reynolds number does in driven flow exhibiting inertial turbulence.
Persistent spiking activity in neuromorphic circuits incorporating post-inhibitory rebound excitation
Authors: Hore Archita , Bandyopadhyay Sharba , Chakrabarti Saswat 
Published: June 2024

Abstract

Objective. This study introduces a novel approach for integrating the post-inhibitory rebound excitation (PIRE) phenomenon into a neuronal circuit. Excitatory and inhibitory synapses are designed to establish a connection between two hardware neurons, effectively forming a network. The model demonstrates the occurrence of PIRE under strong inhibitory input. Emphasizing the significance of incorporating PIRE in neuromorphic circuits, the study showcases generation of persistent activity within cyclic and recurrent spiking neuronal networks. Approach. The neuronal and synaptic circuits are designed and simulated in Cadence Virtuoso using TSMC 180 nm technology. The operating mechanism of the PIRE phenomenon integrated into a hardware neuron is discussed. The proposed circuit encompasses several parameters for effectively controlling multiple electrophysiological features of a neuron. Main results. The neuronal circuit has been tuned to match the response of a biological neuron. The efficiency of this circuit is evaluated by computing the average power dissipation and energy consumption per spike through simulation. The sustained firing of neural spikes is observed till 1.7 s using the two neuronal networks. Significance. Persistent activity has significant implications for various cognitive functions such as working memory, decision-making, and attention. Therefore, hardware implementation of these functions will require our PIRE-integrated model. Energy-efficient neuromorphic systems are useful in many artificial intelligence applications, including human-machine interaction, IoT devices, autonomous systems, and brain-computer interfaces.
Electrical rejuvenation of chronically implanted macroelectrodes in nonhuman primates
Authors: O’Sullivan K P , Orazem M E , Otto K J , Butson C R , Baker J L 
Published: June 2024

Abstract

Objective. Electrodes chronically implanted in the brain undergo complex changes over time that can lower the signal to noise ratio (SNR) of recorded signals and reduce the amount of energy delivered to the tissue during therapeutic stimulation, both of which are relevant for the development of robust, closed-loop control systems. Several factors have been identified that link changes in the electrode-tissue interface (ETI) to increased impedance and degraded performance in micro- and macro-electrodes. Previous studies have demonstrated that brief pulses applied every few days can restore SNR to near baseline levels during microelectrode recordings in rodents, a process referred to as electrical rejuvenation. However, electrical rejuvenation has not been tested in clinically relevant macroelectrode designs in large animal models, which could serve as preliminary data for translation of this technique. Here, several variations of this approach were tested to characterize parameters for optimization. Approach. Alternating-current (AC) and direct-current (DC) electrical rejuvenation methods were explored in three electrode types, chronically implanted in two adult male nonhuman primates (NHP) (Macaca mulatta), which included epidural electrocorticography (ECoG) electrodes and penetrating deep-brain stimulation (DBS) electrodes. Electrochemical impedance spectroscopy (EIS) was performed before and after each rejuvenation paradigm as a gold standard measure of impedance, as well as at subsequent intervals to longitudinally track the evolution of the ETI. Stochastic error modeling was performed to assess the standard deviation of the impedance data, and consistency with the Kramers–Kronig relations was assessed to evaluate the stationarity of EIS measurement. Main results. AC and DC rejuvenation were found to quickly reduce impedance and minimize the tissue component of the ETI on all three electrode types, with DC and low-frequency AC producing the largest impedance drops and reduction of the tissue component in Nyquist plots. The effects of a single rejuvenation session were found to last from several days to over 1 week, and all rejuvenation pulses induced no observable changes to the animals’ behavior. Significance. These results demonstrate the effectiveness of electrical rejuvenation for diminishing the impact of chronic ETI changes in NHP with clinically relevant macroelectrode designs.
Fusion decommissioning and regulation (UK-STEP perspectives)
Authors: Westwood L.N. , Gilbert M.R. , Scott-Mearns N. 
Published: June 2024

Abstract
A Funded Decommissioning Programme (FDP) is submitted to the secretary of state for approval as a requirement for a nuclear site licensee to install or operate a nuclear power station. The United Kingdom Atomic Energy Authority (UKAEA) Spherical Tokamak for Energy Production (STEP) reactor will not require a nuclear site licence and therefore a FDP is currently not a legal requirement under Section 45 of the Energy Act 2008, (HMG 2008 Energy act 2008). However, it is expected that in line with the UK energy sector the UKAEA STEP programme needs to understand what is required both technically and financially to decommission the STEP reactor and associated facilities. This considers the initial summary level documents to support the FDP, which sets out the steps to decommission STEP at the end of its operational life. These documents are not fully developed as the STEP programme is currently in the concept design stage and is expected to be revised as more information becomes available and the Funding Arrangements Plan (FAP) and Decommissioning and Waste Management Plan (DWMP) are developed further along with the Detailed DWMP (DDWMP) which underpins the DWMP is also developed. Ultimately the DWMP, DDWMP and references should demonstrate UKAEA’s plans for the decommissioning of the West Burton site and for the management and disposal of waste
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Waste in this paper includes both primary and secondary waste arisings.
arisings are realistic, clearly defined and achievable. Although this work has been done within the context of the UK and for a spherical tokamak a lot of the designated technical matters and technical matter that are not designated will be applicable to decommissioning outside of the UK as the work for decommissioning is still required, irrespective of the legal framework for funding of the decommissioning. This work is also applicable for other forms of fusion devices, especially as they develop into commercial scale for energy production, as the drivers are associated with the hazards from ionising radiation.
Variable-spectrum mode control of high poloidal beta discharges
Authors: Hanson Jeremy M. , Clement Mitchell , Garofalo Andrea M. , Strait Edward J. 
Published: June 2024

Abstract
DIII-D experiments demonstrate that high pressure, broad current profile equilibria can be accessed in the high poloidal beta regime by optimizing the MHD mode control poloidal spectrum. A novel, variable spectrum (VS) magnetic feedback scheme implemented using the DIII-D internal non-axisymmetric coils (I-coils) facilitated access to reduced internal inductance

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operation above the no-wall beta limit compared with both no feedback and fixed spectrum feedback. In addition, the VS feedback helped avoid beta collapses caused by marginally unstable resistive wall mode activity. The lower and upper I-coil rows were configured in two independent feedback loops, allowing the feedback field’s poloidal spectrum to vary and track changes in the plasma mode structure as the edge safety factor q
95 varied from 11 to 6 during the discharges. The q
95 dependence of the measured phase difference between the lower and upper I-coil rows during VS feedback is qualitatively compatible with ideal MHD simulations of the least-stable plasma kink mode and with plasma response simulations that included kinetic modifications to ideal MHD. The VS feedback approach is a straightforward way to improve resilience to variations in mode structure that occur as plasma parameters change. The demonstrated expansion of the operating space to lower

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is expected to improve the coupling of the plasma kink mode to external fields and beneficial wall eddy currents, and is compatible with high bootstrap fraction operation.
Low gain avalanche detectors for precision timing in the CMS MTD endcap timing layer
Authors: Costa M. ,   the CMS collaboration
Published: June 2024

Abstract
The MIP Timing Detector (MTD) of the Compact Muon Solenoid (CMS) is designed to provide precision timing information (with resolution of ∼40 ps per layer) for charged particles, with hermetic coverage up to a pseudo-rapidity of |η| = 3. This upgrade will reduce the effects of pile-up expected under the High-Luminosity LHC running conditions and brings new and unique capabilities to the CMS detector. The time information assigned to each track will enable the use of 4D reconstruction algorithms and will further discriminate in the time domain interaction vertices within the same bunch crossing to recover the track purity of vertices in current LHC conditions. The endcap region of the MTD, called the Endcap Timing Layer (ETL) will be instrumented with silicon-based low gain avalanche detectors (LGADs), covering the high radiation pseudo-rapidity region between |η| = 1.6 and 3.0. Each endcap will be instrumented with a two-disk system of LGADs, read out by Endcap Timing Readout Chips (ETROCs), being designed for precision timing measurements. We will present an overview of the MTD ETL design, which is detailed in the MTD technical design report. We will also present the R&D and test beam studies that were instrumental for achieving the ETL design, characterization of the LGAD sensors, as well as recent progress on the development of the ETROC readout electronics.
Dynamic diffraction of thermal neutrons in crystals with continuous deformation field
Authors: Shahverdyan A.V. , Trouni K.G. , Kocharyan V.R. 
Published: June 2024

Abstract
The purpose of the work is to consider the basics of the formation of a diffraction wave field of thermal neutrons in the case of Laue transmission geometry of a limited beam of neutrons in the crystal, taking into account the peculiarities of the interaction of thermal neutrons with a continuously and slowly changing deformation field of the crystal net. The conditions of both diffraction blurring and diffraction contraction (focusing) up to the practical restoration of the original shape of the packet will be studied.

An integral form for determining the quasi-amplitudes of diffracted waves within the framework of the original spatially inhomogeneous beams is formulated, based on the constructed functions of the influence of a point source of thermal neutron waves for crystals with a continues deformation field. It has been shown that neutron focusing is effective, which is revealed by a smaller half-width of the focal spot, an increase in the resolving power of the energy spectrum and focusing efficiency.
Characterization of a SiPM-based monolithic neutron scatter camera using dark counts
Authors: Balajthy J. , Brown J. , Brubaker E. , Cabrera-Palmer B. , Cates J. , Goldblum B.L. , Folsom M. , Hausladen P. , Keefe K. , Nattress J. , Negut V. , Nishimura K. , Steele J. , Ziock K. ,   the SVSC collaboration
Published: June 2024

Abstract
The Single Volume Scatter Camera (SVSC) Collaboration aims to develop portable neutron
imaging systems for a variety of applications in nuclear non-proliferation. Conventional
double-scatter neutron imagers are composed of several separate detector volumes organized in at
least two planes. A neutron must scatter in two of these detector volumes for its initial
trajectory to be reconstructed. As such, these systems typically have a large footprint and poor
geometric efficiency. We report on the design and characterization of a prototype monolithic
neutron scatter camera that is intended to significantly improve upon the geometrical shortcomings
of conventional neutron cameras. The detector consists of a 50
mm×56 mm× 60 mm
monolithic block of EJ-204 plastic scintillator instrumented on two faces with arrays of 64
Hamamatsu S13360-6075PE silicon photomultipliers (SiPMs). The electronic crosstalk is limited to
< 5% between adjacent channels and < 0.1% between all other channel pairs. SiPMs introduce a significantly
elevated dark count rate over PMTs, as well as correlated noise from after-pulsing and optical
crosstalk. In this article, we characterize the dark count rate and optical crosstalk and present
a modified event reconstruction likelihood function that accounts for them. We find that the
average dark count rate per SiPM is 4.3 MHz with a standard
deviation of 1.5 MHz among devices. The analysis method we employ
to measure internal optical crosstalk also naturally yields the mean and width of the
single-electron pulse height. We calculate separate contributions to the width of the
single-electron pulse-height from electronic noise and avalanche fluctuations. We demonstrate a
timing resolution for a single-photon pulse to be (128 ± 4) ps. Finally, coincidence analysis is employed to measure
external (pixel-to-pixel) optical crosstalk. We present a map of the average external crosstalk
probability between 2×4 groups of SiPMs, as well as the in-situ timing characteristics
extracted from the coincidence analysis. Further work is needed to characterize the performance
of the camera at reconstructing single- and double-site interactions, as well as
image reconstruction.
Study of silicon photomultipliers for the readout of a lead/scintillating-fiber calorimeter
Authors: Alemanno F. , Bernardini P. , Corvaglia A. , De Matteis G. , Martina L. , Miccoli A. , Panareo M. , Panetta M.P. , Pinto C. , Surdo A. 
Published: June 2024

Abstract
The KLOE electromagnetic calorimeter is expected to be
reused in the Near Detector complex of the DUNE experiment at
Fermilab. The possible substitution of traditional Photomultiplier
Tubes (PMTs) with Silicon Photomultipliers (SiPMs) in the
refurbished calorimeter is the object of this investigation. A block
of the KLOE lead-scintillating fiber calorimeter has been equipped
with light guides and external trigger scintillators. The signals
induced by cosmic rays and environmental radioactivity have been
collected by SiPM arrays on one side of the calorimeter, and by
conventional PMTs on the opposite side. Efficiency, stability, and
timing resolution of SiPMs have been studied and compared with
KLOE-PMTs performance. Conclusions about the convenience of
substituting PMTs with SiPMs are drawn.