bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of structural parameters of needle-ring electrode on the length of argon plasma jet under atmospheric pressure
Authors: Wang Baohuai , Chen Lei , Liu Guiming , Song Peng , Cheng Fanchong , Sun Denglei , Zeng Wen , Xu Long 
Published: March 2023

Abstract
In this paper, a multi-structure needle-ring electrode argon plasma jet device was designed to investigate the influence of reactor structure parameters and discharge parameters on the length of atmospheric pressure non-equilibrium plasma jet. Specifically, the effects of the discharge voltage, the electrode gap, the distance between the end of the high-voltage electrode and the ground electrode, and the volume flow of argon on the jet length were explored. The results demonstrate that the maximum length of the plasma jet in the external environment can reach 80 mm when the inner diameter of the tube is 15 mm; the jet length first increases and then tends to be stable with the increase in the discharge voltage; the jet length presents two peaks with the increasing voltage; the end of jet appears the unstable phenomenon of ‘beating’ when the discharge voltage is high. Besides, the longer the distance between the end of the high-voltage electrode and the ground electrode, the longer the jet length. Nevertheless, the relationship between the distance and the jet length is non-linear. The jet length first increases and then decreases with the increase in the electrode gap. The phenomenon of ‘particle countercurrent’ is observed when the electrode gap and discharge voltage are relatively large. With the increase in the argon volume flow, the plasma jet length also exhibits a trend of first increasing and then decreasing. To sum up, the main factors affecting the length of the plasma jet is transport mode during the plasma transport process.
Neutrino magnetohydrodynamic instabilities in presence of two-flavor oscillations
Authors: Chatterjee Debjani , Misra Amar P , Ghosh Samiran 
Published: March 2023

Abstract
The influence of neutrino flavor oscillations on the propagation of magnetohydrodynamic (MHD) waves and instabilities is studied in neutrino-beam driven magnetoplasmas. Using the neutrino MHD model, a general dispersion relation is derived which manifests the resonant interactions of MHD waves, not only with the neutrino beam, but also with the neutrino flavor oscillations. It is found that the latter contribute to the wave dispersion and enhance the magnitude of the instability of oblique magnetosonic waves. However, the shear-Alfvén wave remains unaffected by the neutrino beam and neutrino flavor oscillations. Such an enhancement of the magnitude of the instability of magnetosonic waves can be significant for relatively long-wavelength perturbations in the regimes of high neutrino number density and/or strong magnetic field, giving a convincing mechanism for type-II core-collapse supernova explosion.
Gravitational radiation from binary systems in f(R) gravity: A semi-classical approach
Authors: Narang Ashish , Mohanty Subhendra , Jana Soumya 
Published: March 2023

Abstract
The rate of energy loss and orbital period decay of quasi- stable compact binary systems
are derived in f(R) theory of gravity using the method of a single vertex graviton emission
process from a classical source. After linearising the f(R) action written in an equivalent
scalar-tensor format in the Einstein frame, we identify the appropriate interaction terms between
the massless spin-2 tensor mode, massive scalar mode, and the energy momentum tensor. The
definition of the scalar field is related to the f(R) models. Then using the interaction vertex
we compute the rate of energy loss due to spin-2 quadrupole radiation, which comes out to be the
same as the Peter-Mathews formula with a multiplication factor, and also the energy loss due to
the scalar dipole radiation. The total energy loss is the sum of these two contributions. Our
derivation is most general as it is applicable for both arbitrary eccentricity of the binary
orbits and arbitrary mass of the scalar field. Using the derived theoretical formula for the
period decay of the binary systems, we compare the predictions of f(R) gravity and general
relativity for the observations of four binary systems, i.e. Hulse-Taylor Binary, PSR J1141-6545,
PSR J1738+0333, and PSR J0348+0432. Thus we put bound on three well-known f(R) dark energy
models, namely the Hu-Sawicki, the Starobinsky, and the Tsujikawa model. We get the best
constraint on f'(R
0)-1 (where R
0 is the scalar curvature of the Universe at the present
epoch) from the Tsujikawa model, i.e |f'(R
0)-1| < 2.09 × 10-4. This bound is
stronger than those from most of the astrophysical observations and even some
cosmological observations.
On minimal realization of topological Lorentz structures with one-loop seesaw extensions in
A4 modular symmetry
Authors: Kashav Monal , Verma Surender 
Published: March 2023

Abstract
The topological classification of one-loop Weinberg operator at dimension-5 leads
to systematic categorization of one-loop neutrino mass models. All one-loop neutrino mass
models must fall in one of these categories. Among these topological categories, loop
extension of canonical seesaw scenarios is interesting in light of the current LHC
run. Apart from one-loop contribution, these extensions result in dominant tree-level
contribution to neutrino masses. The immediate remedy to obtain dominant one-loop
contribution requires combination of flavor symmetries and enlarged field
content. Alternatively, in this work, we propose a minimal way of realizing the
topological structures with dominant one-loop contribution using modular variant of the
permutation symmetries. In such a realization, no new fields are needed apart from those
permitted by the topology itself. For the first time, we have realized one such
topological Lorentz structure(T4-2-i) pertaining to one-loop extension of Type-II seesaw
using modular A4 symmetry. Here, modular weights play an important role in suppressing
tree-level terms and stabilizing the particles running in the loop(Ni
, ρ and
ϕ), thus, making them suitable dark matter candidates. In this work, we have explored
the possibility of fermionic dark matter candidate where right-handed neutrino (N
1) is
assumed to be lightest. We have, also, analyzed the compatibility of the model with
neutrino oscillation data and obtained model predictions for effective Majorana mass
Mee
and CP violation. Furthermore, the predictions on relic density of dark matter
and its direct detection considering bound on lepton flavor violating process,
μ → eγ have, also, been investigated.
Study of Central Intensity Ratio of Seyfert Galaxies in Nearby Universe
Authors: Vinod K. T. , Baheeja C. , Aswathy S. , Ravikumar C. D. 
Published: March 2023

Abstract
We use the recently discovered simple photometric parameter Central Intensity Ratio (CIR) determined for a sample of 57 nearby (z < 0.02) Seyfert galaxies to explore the central features of galaxies and their possible connection with galaxy evolution. The sample of galaxies shows strong anti-correlation between CIR and mass of their central supermassive black holes (SMBHs). The SMBH masses of ellipticals are systematically higher for a given CIR value than those for lenticulars and spirals in the sample. However, the correlation between CIR and central velocity dispersion is weak. CIR appears less influenced by the excess flux produced by the central engine in these galaxies, when compared to spectroscopic parameters like velocity dispersion and O iv flux, and proves to be a fast and reliable tool for estimating central SMBH mass.
NGC 4117: A New Compton-thick AGN Revealed by Broadband X-Ray Spectral Analysis
Authors: Mohanadas Pavithra , Annuar Adlyka 
Published: March 2023

Abstract
In this paper, we present the broadband (0.5–195 keV) X-ray spectral analysis for one of the newly detected AGNs in the Swift-BAT 105 month Hard X-ray Survey Catalog, NGC 4117. According to our ongoing research on low luminosity AGNs from the Swift-BAT 105 month catalog, we examine whether they are indeed low luminosity or heavily obscured AGNs. One of the AGNs in our sample is NGC 4117, where we discover it could be potentially a CTAGN. Therefore to examine NGC 4117 in detail, we combined the high energy Swift-BAT data with low energy data from XMM-Newton and Swift-XRT, and fitted the spectra simultaneously using physically-motivated models. A high absorption occurred at lower energies, i.e., below 3 keV. Past studies suggested that NGC 4117 was heavily obscured with a large column density (∼1023 cm−2). Our fitting suggests that this AGN is in the Compton-thick regime with a predicted line-of-sight column density (N
H,los) of 3.82 × 1024 cm−2 and a torus column density (N
H,tor) of 3.07 × 1024 cm−2. Both models yield intrinsic luminosity of 1.03 × 1042 erg s−1 at 2–10 keV while our bolometric luminosity is 2.05 × 1043 erg s−1, indicating that NGC 4117 is not an intrinsically low luminosity AGN. Rather, it is a standard AGN. The value of Eddington ratio that we obtained is 0.22, suggesting a very high accretion rate for this AGN.
Stellar Dynamical Modeling—Counting Conserved Quantities
Authors: Long Richard J. , Mao Shude , Wang Yougang 
Published: March 2023

Abstract
Knowing the conserved quantities that a galaxy’s stellar orbits conform to is important in helping us understand the stellar distribution and structures within the galaxy. Isolating integrals of motion and resonances are particularly important, non-isolating integrals less so. We compare the behavior and results of two methods for counting the number of conserved quantities, one based on the correlation integral approach and the other a more recent method using machine learning. Both methods use stellar orbit trajectories in phase space as their only input, and we create such trajectories from theoretical spherical, axisymmetric, and triaxial model galaxies. The orbits have known isolating integrals and resonances. We find that neither method is fully effective in recovering the numbers of these quantities, nor in determining the number of non-isolating integrals. From a computer performance perspective, we find the correlation integral approach to be the faster. Determining the algebraic formulae of (multiple) conserved quantities from the trajectories has not been possible due to the lack of an appropriate symbolic regression capability. Notwithstanding the shortcomings we have noted, it may be that the methods are usable as part of a trajectory analysis tool kit.
Atmospheric Parameters and Kinematic Information for the M Giant Stars from LAMOST DR9
Authors: Qiu Dan , Tian Hao , Li Jing , Liu Chao , Long Lin , Shi Jian-Rong , Yang Ming , Zhang Bo 
Published: March 2023

Abstract
A catalog of more than 43,000 M giant stars has been selected by Li et al. from the ninth data release of LAMOST. Using the data-driven method SLAM, we obtain the stellar parameters (T
eff,

log

g

, [M/H], [α/M]) for all the M giant stars with uncertainties of 57 K, 0.25 dex, 0.16 dex and 0.06 dex at SNR > 100, respectively. With those stellar parameters, we constrain the absolute magnitude in the K − band, which brings distance with relative uncertainties around 25% statistically. Radial velocities are also calculated by applying cross correlation on the spectra between 8000 and 8950 Å with synthetic spectra from ATLAS9, which covers the Ca ii triplet. Comparison between our radial velocities and those from APOGEE DR17 and Gaia DR3 shows that our radial velocities have a system offset and dispersion around 1 and 4.6 km s−1, respectively. With the distances and radial velocities combining with the astrometric data from Gaia DR3, we calculate the full 6D position and velocity information, which are able to be used for further chemo-dynamic studies on the disk and substructures in the halo, especially the Sagittarius Stream.
Evidence of a Third Body and Photometric Solutions of a High Temperature Marginal Contact Binary CW Aqr
Authors: Vijaya A. , Sriram K. 
Published: March 2023

Abstract
Marginal contact binary systems are an important class of binary systems in exploited by astronomers to understand various astrophysical phenomena as they bridge both semi-detached and overcontact stages. We studied the photometric data of CW Aqr using the JCB 1.3 m telescope (JCBT), Kepler, and TESS to understand the period variations and constrain the light curve solutions. We noted that the period of CW Aqr is increasing with a mass transfer rate of

m

̇

= 7.53 × 10−8
M
⊙ yr−1 from the secondary to the primary component. We also ascertained cyclic deviations along with a parabolic trend in the O − C diagram. The residuals displayed a sinusoidal trend which was fitted with an LTTE, indicating the presence of a third body with an orbital period of P
3 ∼10 yr and e = 0.10. We fitted the JCBT, Kepler, and TESS photometric normalized light curves and noted the mass ratio to be q ∼ 0.32 for both contact and semi-detached configurations. We identified a temperature difference between the primary and secondary components of ∼2500 K. No activity signatures were found in the observed light curves which were also evident from the Hα line studies where the filled-in effect was not seen. Overall our study suggests that CW Aqr is a marginal contact binary with a low mass ratio evolving toward a semi-detached configuration. However, it may merge if the period increases due to ongoing mass transfer accompanied by a lowering in the mass ratio and later oscillate back to the period-decreasing trend due to angular momentum loss over a few cycles of thermal relaxation oscillations followed by instability.
Study of correlations between LOC/SOC transition, intrinsic toroidal rotation reversal and TEM/ITG bifurcation with different working gases in TCV
Authors: Bagnato F. , Duval B.P. , Krutkin O. , Iantchenko A. 
Published: March 2023

Abstract
The effects of different working gases on the transition from linear ohmic confinement (LOC) regime to saturated ohmic confinement (SOC) regime and its relation to the intrinsic toroidal rotation reversal phenomenon were explored in the TCV tokamak. The energy confinement saturation was studied across D, H and He density ramps, and a range of ECRH injection power and through variations of ohmic plasma current. The occurrence of rotation reversal, concomitantly with the LOC–SOC transition, was observed only for certain cases, making us formally exclude a causal relation between the two phenomena. A strong correlation between the evolution of toroidal rotation profiles and electron density gradients was, however, observed, in agreement with previous works (Lebschy et al 2017 Nucl. Fusion
58 026013; Hornsby et al 2018 Nucl. Fusion
58 056008). Linear gyrokinetic simulations were performed to probe the turbulent regime of these discharges, showing a dominance of trapped electron mode (TEM) during the LOC phase and a mixture of TEM and ion temperature gradient (ITG) following the transition to SOC regime in D. Such a TEM/ITG bifurcation was less pronounced in H and He. MHD activity was monitored throughout the discharges and possible correlations between sawteeth instability activity, energy confinement time saturation and rotation reversal are highlighted.
Screen-printed, flexible, and eco-friendly thermoelectric touch sensors based on ethyl cellulose and graphite flakes inks
Authors: Figueira J , Bonito R M , Carvalho J T , Vieira E M F , Gaspar C , Loureiro Joana , Correia J H , Fortunato E , Martins R , Pereira L 
Published: March 2023

Abstract
Despite the undoubtable interest in energy conversion, thermoelectric (TE) materials can be approached from a temperature-sensitive perspective, as they can detect small thermal stimuli, such as a human touch or contact with cold/hot objects. This feature offers possibilities for different applications one of them being the integration with scalable and cost-effective, biocompatible, flexible, and lightweight thermal sensing solutions, exploring the combination of sustainable Seebeck coefficient-holding materials with printing techniques and flexible substrates. In this work, ethyl cellulose and graphite flakes inks were optimized to be used as functional material for flexible thermal touch sensors produced by screen-printing. Graphite concentrations of 10, 20 and 30 wt% were tested, with 1, 2 and 3 printed layers on four different substrates—office paper, sticker label paper, standard cotton, and organic cotton. The conjugation of these variables was assessed in terms of printability, sheet resistance and TE response. The best electrical-TE output combination is achieved by printing two layers of the ink with 20 wt% of graphite on an office paper substrate. Subsequently, thermal touch sensors with up to 48 TE elements were produced to increase the output voltage response (>4.5 mV) promoted by a gloved finger touch. Fast and repeatable touch recognition were obtained in optimized devices with a signal-to-noise ratio up to 340 and rise times bellow 0.5 s. The results evidence that the screen-printed graphite-based inks are highly suitable for flexible TE sensing applications.
Mapping the magnetocaloric effect at the microscale on a ferromagnetic shape memory alloy with infrared thermography
Authors: Pereira Maria J , Santos Tiago , Correia Rafael , Amaral João S , Amaral Vitor S , Fabbrici Simone , Albertini Franca 
Published: March 2023

Abstract
An innovative study of the magnetocaloric effect (MCE) was performed by mapping the effect based on direct measurements of the temperature change during magnetic field cycles with microscopic resolution (85 μm) on a Co-doped Ni–Mn–Ga bulk sample using infrared thermography on the whole sample. The MCE maps were constructed for different sample temperatures (T
sample), cycling both on heating (from 272.8 K up to T
sample, with T
sample ⩽ 327.0 K) and on cooling (from 340.0 K down to T
sample, with T
sample ⩾ 266.8 K), cycling a 1.2 T magnetic field at each T
sample value. The MCE maps were calculated to evaluate the amplitude of the effect at the microscale for all T
sample values. This allows to analyze the contribution of each micrometric portion of the sample to the spatially heterogeneous behavior that was found. Significant differences of the MCE on heating and cooling are present associated to inhomogeneity dynamics, mostly near the structural transformation. The amplitude of the MCE and its inhomogeneity are both much more pronounced on the heating process. On the cooling process the effect behaves quite homogeneously since the structural transformation already occurred during the cooling to reach T
sample. The behavior of the MCE at selected map coordinates was scrutinized, revealing significant differences amongst sample locations. Moreover, the extreme amplitudes of MCE registered for diverse micro-regions occur at different temperatures, suggesting that the structural transformation occurs at varying temperatures and with different magnitudes. The study innovates by constructing MCE maps to evaluate minority behaviors in the MCE in contrast with the average behavior of the effect. This study displays the capability to discriminate the behavior of the transformation at the microscale.
Microstructural and sensor data analysis of friction stir processing in fabricating Al6061 surface composites
Authors: Saxena Pragya , Bongale Arunkumar , Kumar Satish , Jadhav Priya 
Published: March 2023

Abstract
Aluminium alloys, having high strength, ductility, and toughness, are useful structural materials. Composites of these with ceramic reinforcements improve the hardness and wear-resistance, making them suitable for use in the aerospace and automobile industries. Since surface properties play a crucial role for most applications, the manufacturing of surface composites of aluminum alloys is recommended. For this purpose, friction stir processing (FSP) is being utilized nowadays. It refines the microstructure with a homogeneous dispersion of reinforcements into the matrix and improves physical characteristics like surface hardness, wear resistance, strength, etc, while retaining the original characteristics of remaining volume. The study aims to investigate and compare the temperature and vibration sensor data while manufacturing Al6061 surface hybrid composites by using FSP tools with different geometries. The FSP method is utilised for the fabrication of the composites with the copper and graphite powders mixture (1:1), reinforced into the matrix surface by using two H13 tools with two different pin profiles - threaded cylindrical and plain cylindrical. Holes of different diameters and depths are drilled on the Al6061 matrix for reinforcement addition. This FSP process is investigated using a thermal gun and a Cross-Domain Development kit for temperature and vibration measurement. The variation in the vibration signals occurring on the composite workpiece during the entire process with the temperature measurements at equal intervals, is obtained. It is found that both the temperature and vibration amplitudes (400 °C and 1111Hz) are lower in the composites fabricated by FSP tool with threaded pin profile than that by FSP tool with plain pin profile (455 °C and 1305 Hz). Also, the processed samples are investigated for the microstructure by Field Emission Scanning Electron Microscope and Energy-Dispersive x-ray Spectroscopy tests. It is found that the reinforcements are dispersed more uniformly and much reduced in size (0.5482 μm) when prepared by the FSP tool with threaded cylindrical pin, while these particles are heterogeneously dispersed and less reduced in size (1.11 μm) when processes by the FSP tool with plain cylindrical pin. This research can be used to further monitor and control properties like temperature, vibration, force, current, etc, to obtain a uniform reinforcement dispersion with improved mechanical properties during the surface composite preparation by FSP.
Monolithic heterogeneous integration of Si photodetector and Van der Waals heterojunction with photocurrent enhancement
Authors: Li Jiaqi , Li Zebin , Xie Sheng , Su Yue , Mao Xurui 
Published: March 2023

Abstract
Two-dimensional material has many novel features, which can be used to significantly improve the performance of traditional photonic and electronic devices. Therefore, the development of silicon/two-dimensional material monolithic heterogeneous integrated photodetector has attracted extensive attention worldwide. In this paper, we present a method to enhance the response of photocurrent of silicon-based PN junction photodetectors by using two-dimensional material Van der Waals heterostructures. The MoS2/graphene/N+ silicon monolithic heterogeneous integrated Van der Waals heterostructure is used as an NPN-type phototransistor to realize the amplification of photocurrent. When the device is irradiated, the photogenerated electron hole pairs in the semiconductor are separated by the applied electric field. However, graphene has a low density of defect states, and only a few electrons from N+ silicon can be recombined in graphene. Meanwhile, the graphene layer is very thin, and the positively biased graphene/N+ silicon junction and reversed-biased MoS2/graphene junction will accelerate the electrons to across the graphene layer and directly into MoS2. Using MXenes as the contact electrode of the MoS2 can eliminate the Fermi level pinning effect. The experimental results show that the photoresponsivity and photocurrent gain increase with the bias voltage, in the range of 0 to 5 V bias voltage. And the optical Ion/Ioff ratio increases by nearly 50 times. This research provides new insights for the detection of weak light and design for the photon computing device.