bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations of magnetic reconnection in the deep solar atmosphere in the Hεline
Authors: Rouppe van der Voort Luc H. M. , Joshi Jayant , Krikova Kilian 
Published: January 2024

Context.Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon known as Ellerman bombs (EBs). It is most common to observe EBs in the Hαand Hβspectral lines. High-quality shorter-wavelength Balmer line observations of EBs are rare, but have the potential to provide the most highly resolved view on magnetic reconnection.Aims.We aim to evaluate the Hε3970 Å line as an EB diagnostic by analyzing high-quality observations in different Balmer lines.Methods.Observations of different targets and viewing angles were acquired with the Swedish 1-m Solar Telescope. These observations sample EBs in different environments: active regions, the quiet Sun, and the penumbra and moat of a sunspot. We employed an automated detection method for quiet-Sun EBs based onk-means clustering.Results.Ellerman bombs in the Hεline show similar characteristics as in the longer-wavelength Balmer lines: a higher intensity than in the surroundings, rapid variability, and a flame-like morphology. In a 24 min quiet-Sun time series, we detected 1674 EBs in the Hεline. This is 1.7 times more EBs than in Hβ. The quiet-Sun EBs measured in Hεare very similar to those in Hβ: They have similar lifetimes and a similar area, brightness, and spatial distribution. Most of the EBs detected in Hεare closer to the limb than their Hβcounterparts because the Hεline core EB emission is formed higher in the atmosphere than the HβEB wing emission.Conclusions.We conclude that the Hεline is well suited for studying EBs, and consequently, for measuring the dynamics of magnetic reconnection in the solar atmosphere at the smallest scales. Our findings suggests that the deep atmosphere in the quiet Sun may host more than 750 000 reconnection events with an EB signature at any time. This is significantly more than what was found in earlier Hβobservations.
Aging in light of digitalization of healthcare
Authors: Arzroomchilar Ehsan 
Published: January 2024

AbstractWith the advancements in digital technologies, notions such as aging in place have gained currency. But, next to technical issues concerning the extent to which full-blown aging in place is possible, philosophical and ethical questions have been also raised. An important dimension of the digitalization of healthcare is how would aging look to both older adults and the public in the wake of such systems. In this article, I will suggest integrating postphenomenology into Age Studies to explore how aging comes to be conceptualized. An advantage of postphenomenology is that it is anchored in a first-person perspective, and in this sense, it may be a perfect fit to enhance our awareness about the impacts of the digitalization of health on older adults from their own point of view. I will also argue that postphenomenlogy can throw light on digital technologies in their actual use. This may help researchers go beyond merely exploring conditions of use and adoption implemented through notions such as usability, trust, privacy, dignity, and the like, and gain knowledge of how users’ relationship with their surroundings reconfigures after exposure to digital assistive technologies.
The radiant massive magnetic dipole
Authors: Diaz Polanco José , Ayala Hoffmann José , Ujevic Maximiliano 
Published: January 2024

Abstract
We present an exact, time-dependent solution for the Einstein field equations that models the coupling between an anisotropic fluid and a magnetic field in an axially symmetric space-time. By carefully selecting the metric components, we achieve a convenient separation of variables that enables us to solve Einstein’s field equations and obtain a solution that evolves into the Gutsunaev–Manko massive magnetic dipole. The analysis of the thermodynamic quantities suggests that this solution may represent a pulse of radiation emitted by a massive object with magnetic properties, as for example pulsars or neutron stars.
Wearable microfluidic sweat collection platform with a calorimetric flow rate sensor for realtime and long-term sweat rate measurements
Authors: Silverio Angelito A , Ho Eric Tatt Wei , Ang Jerard , Esguerra Kiara 
Published: January 2024

Abstract
This work presents the design and fabrication of a wearable microfluidic patch-based system for sweat collection with a calorimetric flow rate sensor based on heat convection for measuring sweat rate (SR). The effects were predicted using a 3D multi-physics simulator and were verified on a fabricated patch made of polyimide layers. The sensor can detect surface temperature gradients of 302–312 K caused by fluid flowing thru the microfluidic channels at a rate of 0.5–23 µg s−1 that fall within the physiological range of SR. Meanwhile, the relation between flow rate and temperature gradient is highly linear (Pearson r2
= 0.999) and repeatable. This work also demonstrates a low-cost method for patterning microfluidic channels on flexible substrates which can be used for mass production of wearable patches.
Stable skyrmions in Co/Ni-based nanopillars with perpendicular magnetization anisotropy
Authors: Lv Gang , Zhang Hong , Gao Feng , Li Guihua , Liu Tianliang , Liu Yaowen 
Published: January 2024

Abstract
Micromagnetic simulations have been conducted to explore the formation rules of stable skyrmions in Co/Ni-based perpendicular magnetization anisotropy nanopillars with Dzyaloshinskii–Moriya Interaction (DMI). The results show that an appropriate perpendicular magnetic field can generate a robust Néel-type skyrmion magnetic configuration in the free layer with a 5° tilted easy axis. The creation and stability of skyrmion states also depends on the strength of the DMI and the size of nano-disk. Furthermore, we observed intriguing behavior in the case of the free layer with a perfectly perpendicular easy axis. Skyrmion states appeared in two distinct regions of perpendicular magnetic field when both perpendicular and in-plane magnetic fields were applied. This discontinuity arises from the nucleation of initial Bloch-type skyrmions. These results contribute to comprehending the formation mechanism of stable skyrmions in perpendicular magnetic anisotropy multilayers and may promote the development of skyrmion-based nanodevices.
River video flow measurement algorithm with space-time image fusion of object tracking and statistical characteristics
Authors: Yuan Youwei , Che Guolin , Wang Chao , Yang Xuan , Wang Jianping 
Published: January 2024

Abstract
River flow monitoring serves as a crucial data source in hydrological stations, employing the widely adopted space-time image velocimetry (STIV) method both domestically and internationally. However, current methods yield space-time (ST) image trajectories with limited usable information, particularly due to the interference of complex flow characteristics and harsh outdoor environments in natural rivers. This interference leads to errors in detecting the main orientation of texture, consequently reducing measurement accuracy. To overcome these challenges, this paper proposes an river video flow measurement algorithm with ST image fusion of object tracking and statistical characteristics. The Lucas–Kanade tracking algorithm is employed to track velocity points and generate tracking trajectories. These trajectories’ coordinates are then fitted into straight lines to automatically arrange velocity-measuring lines in natural rivers. The algorithm leverages multi-scale detail boosting and Gaussian directional stretch filtering to enhance the quality and texture trajectories of ST images. Furthermore, background noise filtering and stripe noise filtering are applied to denoise the ST images, effectively mitigating the impact of noise caused by the natural river environment and camera equipment. The proposed algorithm incorporates projection statistical characteristics algorithms to accurately detect the dominant texture direction, enabling precise calculation of mean velocity and cross-sectional discharge of the river. Experimental validation was conducted in both natural and regular river channels, demonstrating the superior performance of the proposed solution compared to widely used large-scale particle image velocimetry, STIV, MobileNet-STIV and FD-DIS-G algorithms. The algorithm exhibited higher accuracy, stability, and applicability, with errors at each velocity-measuring point below 10%, and relative errors of the calculated mean velocity and cross-sectional discharge below 3%. This affirms the algorithm’s superior accuracy, stability, and applicability.
Study of the demagnetization behavior of no-insulation persistent-current mode HTS coils under external AC fields by 3D FEM simulation
Authors: Zhong Zhuoyan , Wu Wei , Ma Guangtong , Jin Zhijian 
Published: January 2024

Abstract
The no-insulation (NI) winding technique is promising for applications in the persistent-current mode (PCM) operation of high-temperature superconducting (HTS) coils. To produce an NI PCM coil, it is essential to understand its demagnetization behavior (i.e. decay of persistent DC current) under an external AC field, which occurs in maglev trains, electric machines and other dynamic magnet systems. For this purpose, a 3D finite-element method (FEM) model, capturing the full electromagnetic properties of NI HTS coils is established. This work studied three kinds of AC fields, observing the impact of turn-to-turn contact resistivity on demagnetization rates, which is attributed to current distribution modulations. Under a transverse AC field, the lower contact resistivity attracts more transport current to flow in the radial pathway to bypass the ‘dynamic resistance’ generated in the superconductor, leading to slower demagnetization. Under an axial AC field, the demagnetization rate exhibits a non-monotonic relation with the contact resistivity: (1) the initial decrease in contact resistivity leads to a concentration of induced AC current on the outer turns, which accelerates the demagnetization; (2) the further decrease in contact resistivity makes the current smartly redistribute to avoid flowing through the loss-concentrated outer turns, thus slowing down the demagnetization. Under a rotating DC field, a hybrid of transverse and axial fields, the impact of contact resistivity on the demagnetization rate exhibits combined characteristics of the transverse and axial components. Additionally, quantitative prediction of the demagnetization rate of NI PCM coil under external AC field is instructive for practical designs and operations, which is tested by this 3D FEM model, and a comparison with experimental results is conducted.
Impact of micro-indentation load/time and Zinc concentration on the thermo- mechanical characteristics of amorphous Se78Te20Sn2 alloy
Authors: Saraswat Vishnu , Dahshan A , Elsaeedy H I , Mehta Neeraj 
Published: January 2024

Abstract
We have performed hardness measurement experiments under different loads and loading times by performing micro-indentation marks in the present work. Chalcogenide glasses (ChGs) comprising Se78Te20Sn2 and Se78-xTe20Sn2Znx (where x = 0, 2, 4, & 6) alloys are the subject of micro-indentation tests in this work. We have utilized both micro-indentation and optical microscopic methods to determine Vickers hardness. Thermal glass transition phenomena have been identified through DSC techniques. The modulus of elasticity (E), an essential mechanical property, has been evaluated using established empirical equations. Further, we have studied other mechanical parameters [e.g., minimal micro-void formation energy (E

h
), glass’s fragility index (m), micro-void volume (V

h
), etc] and the covalent character of the glassy system. Additionally, various physical parameters, including density, molar volume, and compactness, have also been determined. The results emphasize that the different thermo-mechanical parameters investigated in this study achieve their most extreme values at the highest concentration of Zn. However, the energy of micro-void formation within the glassy network of quaternary glasses remains relatively unchanged after the introduction of Zn into the parent STS alloy;
High-quality random bit generation based on a cascade-coupled nano-laser system
Authors: Liu G P , Mu P H , Guo G , Liu X T , Hu G S 
Published: January 2024

Abstract
In this paper, a novel method is proposed to generate high-quality chaotic signals using three cascade-coupled nano-lasers (NLs), and generate high-speed, high-quality random number sequences. The master NL (MNL) is subjected to optical feedback, and its output is injected into the intermediate NL (INL), which is further injected into the slave NL (SNL). In the simulation, we first adjust proper parameters so that the SNL generates a chaotic signal with a large bandwidth and time-delay signature concealment. After performing self-delayed differential processing on the chaotic signal, and utilizing an 8-bit analog-to-digital converter for sampling and quantization, followed by extraction of the m-bits least significant bit, the final random bit sequence is obtained. Finally, we use NIST SP 800-22 to test the generated random numbers. The results demonstrate that the obtained random number sequence successfully passed all tests specified by NIST SP 800-22.
Automated experimental design of safe rampdowns via probabilistic machine learning
Authors: Mehta Viraj , Barr Jayson , Abbate Joseph , Boyer Mark D , Char Ian , Neiswanger Willie , Kolemen Egemen , Schneider Jeff 
Published: January 2024

Abstract
Typically the rampdown phase of a shot consists of a decrease in current and injected power and optionally a change in shape, but there is considerable flexibility in the rate, sequencing, and duration of these changes. On the next generation of tokamaks it is essential that this is done safely as the device could be damaged by the stored thermal and electromagnetic energy present in the plasma. This works presents a procedure for automatically choosing experimental rampdown designs to rapidly converge to an effective rampdown trajectory. This procedure uses probabilistic machine learning methods paired with acquisition functions taken from Bayesian optimization. In a set of 2022 experiments at DIII-D, the rampdown designs produced by our method maintained plasma control down to substantially lower current and energy levels than are typically observed. The actions predicted by the model significantly improved as the model was able to explore over the course of the experimental campaign.
Impact of Dipole Quadrupolar Errors in Fcc-ee
Authors: García-Jaimes C , Pieloni T , van Riesen-Haupt L , Seidel M , Tomás R 
Published: January 2024

Abstract
FCC-ee performance is challenged by magnetic errors and imperfections. Magnetic design simulations predict a systematic quadrupolar component in the arc dipoles significantly impacting the machine optics. This paper studies the impact of this component in the beta-beating and explores potential mitigations.
Modeling SuperKEKB Backgrounds with the Belle II Electromagnetic Calorimeter
Authors: Liptak Zachary J , Atsuta Masahiro 
Published: January 2024

Abstract
The largest current obstacle to SuperKEKB’s luminosity goals is currently beam-related backgrounds occurring during accelerator operation. Thus, understanding the level of these backgrounds is of crucial importance for the future of the facility. In this work, we take advantage of the Belle II Electromagnetic Calorimeter’s near-total coverage of the interaction region to create a spatial model of beam-induced backgrounds with the aim of providing fast feedback to improve accelerator conditions.
GaAs cathode activation with Cs-K-Sb thin film
Authors: Kuriki M , Liptak Z J , Guo L , Jin X , Yamamoto N 
Published: January 2024

Abstract
GaAs cathodes are unique devices which generate a spin-polarized electron beam by the photoelectric effect when illuminated with a circularly polarized laser. Thin-film Negative Electron Affinity (NEA) surfaces have an essential role in spin polarized beam production, but they have limited lifetimes. In this study, we activate GaAs as an NEA cathode by evaporating Cs, K, and Sb metal on its cleaned surface. The experimental results of quantum efficiency measurements taken after evaporative deposition of the multi-alkali surface are presented here.
A feasibility study into the quasi-frozen spin regime of operation of the NICA storage ring
Authors: Aksentev A E , Melnikov A A , Senichev Y V , Kolokolchikov S D , Ladygin V P , Syresin E M , Butenko A V 
Published: January 2024

Abstract
This study is motivated by the search for the electric dipole moment (EDM) of elementary particles. The most promising idea in that regard is the “Frozen Spin” concept first proposed by the BNL. This concept, however, requires the building of a brand-new facility devoted to the EDM-search. NICA is not such a facility, hence the need for a modification compatible with the existing optics; one that wouldn’t disrupt the ring’s capability for parallel experiments. Such a modification is the “Quasi-Frozen Spin” idea, realized by adding transport channels, bypassing the ring’s straight sections. Wien-filters are placed in these channels in order to compensate spin-rotations caused by the ring’s arc dipoles, thus making its net spin-transfer matrix unitary. Even though, during its movement along the beam line, the beam’s polarization vector deviates from alignment with the momentum vector, this motion is regular and fits within one beam revolution, allowing for the buildup of the EDM-signal. The present study shows that the “Quasi-Frozen Spin”-specific optics is consistent with the existing NICA lattice and that the modified structure is capable of maintaining a requisite spin-coherence time.
Conceptual design of the magnetised iron block system for the SHADOWS experiment
Authors: Stummer F , Banerjee D , Baratto Roldan A , Bernhard J , Boogert S T , Brugger M , Charitonidis N , D’Alessandro G L , Deniaud M , Dyks L A , Gatignon L , Gerbershagen A , Gibson S , Lanfranchi G , Metzger F , Murphy R , Mussolini C A , Nevay L J , Parozzi E , Rae B , Schuh-Erhard S , Simon P , Shields W , Stergiou V , Van Dijk M , Zickler T 
Published: January 2024

Abstract
SHADOWS [1, 2] is an intended future beam dump experiment in the CERN North Area, aiming to search for feebly interacting particles (FIPs) [3] created in 400 GeV/c proton interactions. Due to its proposed off-axis location alongside the K12 beamline [4], the SHADOWS detector can be placed potentially very close to the beam dump, enabling it to search for FIPs in unexplored parts of the parameter space. In order to guarantee good quality of a potential signal, it is crucial to reduce any backgrounds of Standard Model particles as much as possible. The dominant background downstream the beam dump is caused by muons [1]. This introduces the need of a dedicated muon sweeping system consisting of magnetised iron blocks (MIBs) to actively mitigate this background component. We present the conceptional design studies in the framework of the Conventional Beams Working Group of the Physics Beyond Colliders Initiative at CERN [5, 6].
Earthquake Measurements and Those Analysis on IR Components and Belle II Detector in KEK
Authors: Yamaoka H , Masuzawa M , Kanayama T , Maki M 
Published: January 2024

Abstract
Earthquakes frequently occur in Japan. Even though countermeasures are thoroughly considered and well executed, earthquakes still impact facilities and experimental devices. The large relative displacements induced by an earthquake can damage beam pipe bellows and interfere with sub-detectors by causing the tolerance between them to disappear. Even magnet quenches have been triggered by induced voltages caused by the relative displacements between the superconducting solenoids (i.e., the detector solenoid and the compensating solenoids surrounding the final focus quadrupole magnets, or QCSs). In response, we installed acceleration sensors on the Belle II detector and mounted gap sensors on the QCSs to measure the relative displacements. These measurements enabled the characteristics of the earthquakes that have affected the Belle II detector to be analysed. Response spectrum analyses (RSAs) of the Belle II detector were conducted to evaluate the impact of earthquakes according to the ground motion measurements. We then compared the measurements to the RSA results, which led to an idea for a countermeasure.
Polarization Based Out-Coupling for Cavity Based X-ray FELs
Authors: Rauer Patrick 
Published: January 2024

Abstract
Cavity Based X-ray Free-Electron Lasers (CBXFELs) promise fully 3D coherent, very brilliant and shot-to-shot stable X-ray pulses. For CBXFELs the X-ray radiation is trapped in an X-ray optical cavity, which is formed using Bragg-reflecting crystal mirrors. As is the case for laser systems in the optical regime, a major question for the CBXFELs is how to couple out the radiation from the cavity. Possibilities range from employing semi-transparent thin crystals, over manipulation of the electron phase space density to cavity dumping schemes. In this work, making use of the strong polarization of Bragg reflection shall be studied for out-coupling. As the radiation does not change its polarization during Bragg reflection, reflection in the direction of the polarization vector is suppressed. By adjusting the 3D orientation of the crystals with respect to the polarization axis of a linearly polarized undulator, or vice versa, the transmission through the crystals can be tailored to some degree independently of the crystal thickness.
Helical Undulators of Magnetized Helices and Ring Sectors
Authors: Magory Eyal , Balal Nezah , Bratman Vladimir L. 
Published: January 2024

Abstract
The periodic system of a spiral array of magnetized ring sectors (quasi-helix) creates a helical field, which is close in structure and magnitude to the field in the system of helical magnets. Such a system of a relatively small number of readily accessible magnets can be easier to manufacture and assemble than a system containing mag-netized helices made from single pieces. In this paper, we study the dependence of the helical field on the number of sectors per undulator period. Short prototypes consisting of longitudinally and radially magnetized sectors were experimentally studied. The maximum value of the helical field on the axis of a quasi-helix of longitudinally and radially magnetized ring NdFeB sectors with a period of 2 cm and a relatively large inner diameter of 8 mm is 0.28 T and 0.34 T, respectively. This corresponds to a field of 0.74 T in the case of four alternately longitudinally and radially magnetized Halbach-like quasi-helices of pre-magnetized sectors and a hybrid system assembled from longitudinally pre-magnetized sectors and preliminarily non-magnetized steel sectors. Such undulators can provide a high oscillatory electron velocity and seem promising for increasing the efficiency of FELs and inverse FELs in various frequency ranges.
Evaluation of a compact electron preinjector using a low beta (β) acceptance X-band accelerating structure
Authors: Williams SD , Dowd RT , Rassool RP , Sheehy SL , Taylor GN , Volpi M 
Published: January 2024

Abstract
At the University of Melbourne X-LAB we are investigating the use of a low β acceptance X-band accelerating structure as part of the design of an all X-band RF electron preinjector optimised for the production of low emittance electron bunches for medical physics applications and compact light source development.
In this work we will elaborate on the estimated performance, design issues, and optimisation methodology of the preinjector beamline.