bluuebunny/crossref_metadata_2025 huggingface dataset:
Sizing of particles and droplets using 3D-PTV, an OpenPTV post-processing tool
Authors: de la Torre R G Ramirez , Jensen Atle
Published: March 2023

A methodology to obtain particle sizes from images was created, this tool can be used as a post-processing tool to the open source software OpenPTV. The proposed methodology uses the same images and information obtained during the 3D calibration of OpenPTV to estimate the real sizes of the observed particles. The objective of this paper is to introduce the followed methodology to create a sizing tool and validate the technique with different solid particles and water droplets. The method requires an extra calibration with a flat target containing circles of different sizes, but if the calibration is successful, the sizes of particles can be estimated reliably with a maximum relative error of 10%, as long as the particle diameter correspond to at least three pixels width in the obtained images.
Mechanical ventilation intervention based on machine learning from vital signs monitoring: a scoping review
Authors: Baidillah Marlin Ramadhan , Busono Pratondo , Riyanto Riyanto
Published: March 2023

Asynchronous breathing (AB) during mechanical ventilation (MV) may lead to a detrimental effect on the patient’s condition. Due to the massive amount of data displayed in a large ICU, a machine learning algorithm (MLA) was proposed extensively to extract the patterns within the multiple continuous-in-time vital signs, to determine which are the variables that will predict the AB, to intervene in the MV as an early warning system, and finally to replace a highly demand of clinician’s cognition. This study reviews the MLA for prediction and detection models from vital signs monitoring data for MV intervention. Publication on MLA development on MV intervention based on vital signs monitoring to support clinicians’ decision-making process was extracted from the three electronic academic research databases Web of Science Core Collection (WoSCC), ScienceDirect, and PUBMED Central to February 2023. 838 papers from the electronic academic research databases are extracted. There are 14 review papers, while 25 related papers that pass with the quality assessments (QA). Few studies have been published that considered VS monitoring data along with the MV parameters waveforms for MV intervention. Vital signs monitoring data is not the only predictor in the developed MLA. Most studies suggested that developing the MLA for direct MV intervention requires more concern in the pre-processing of real-time data to avoid false positive and false detection than developing MLA itself.
A compact ultra-wideband sub-nanosecond pulse generator with step recovery diodes
Authors: Liu Guancong , Xiao Xia , Lu Min , Zhang Xiaofeng , Kikkawa Takamaro
Published: March 2023

This article presents a compact ultra-wideband (UWB) sub-nanosecond monocycle pulse generator. The proposed circuit has a simple structure and low cost, and its core components are step recovery diodes (SRDs). It is composed of a power supply circuit, pulse drive circuit, short pulse-forming circuit, and pulse-shaping circuit. A transistor-based drive circuit is used to generate a drive pulse with sharp fall time. Then, a sub-nanosecond pulse width is realized through the combination of two SRDs in series and parallel. Finally, a monocycle pulse is directly formed by the inductance-based differentiator. This design achieves a full pulse width of 406 ps with a 260 mV peak-to-peak amplitude and a −10 dB bandwidth of 510 MHz to 6.1 GHz at a pulse repetition frequency of 10 MHz square waveform. The symmetry and ringing level are 96.9% and −25.3 dB, respectively, providing good symmetry and low ringing with a circuit size of 55 × 15 mm. In actual experiments, two identical UWB antennas with appropriate bandwidth are used to radiate a monopulse to breast phantoms. The results and uncertainty analyses of the test system show that there are distinguishable differences under diverse tumor phantoms and locations, proving that the proposed pulse generator is attractive for the application of UWB breast cancer detection.
Upconversion phosphor thermometry for use in thermal barrier coatings
Authors: Feuk Henrik , Nilsson Sebastian , Richter Mattias
Published: March 2023

Measuring the temperature below the surface of a thermal barrier coating (TBC) using a thin phosphor layer is challenging primarily due to the absorption and scattering of laser excitation light and phosphor luminescence as they propagate through the coating. One way to increase phosphor luminescence could be to use upconversion phosphor thermometry, which is investigated in the current study. It is attractive because using longer excitation wavelengths reduces the absorption and scattering in TBCs as 8% wt. yttria-stabilize zirconia (8YSZ) generally has lower scattering and absorption coefficients around 1000 nm than at 532 and 355 nm. Therefore, the viability of upconversion to measure the temperature at the bottom of a TBC was evaluated for the first time and was compared with the more conventional downconversion phosphor thermometry. The current work involved an experimental study of several phosphors with lanthanides doped in the 8YSZ host, which were excited through downconversion by pulsed 355 nm and 532 nm laser light and through upconversion with 965 nm laser light. The YSZ:Er,Yb and YSZ:Ho,Yb phosphors show promise for upconversion phosphor thermometry. The experimentally acquired optical phosphor characteristics were used to simulate laser light and phosphor luminescence propagation in TBCs using Kubelka–Munk theory. This was to evaluate the signal strength with upconversion excitation compared to downconversion excitation. Upconversion excitation resulted greater signal strength from an embedded phosphor layer than 532 nm excitation and much higher than 355 nm excitation. Upconversion lifetime phosphor thermometry also resulted in improved phosphor lifetime temperature sensitivity. Coupled with reduced interference from background luminescence from impurities in TBCs with upconversion, it is a promising method for temperature measurements with the thermographic phosphor embedded in or underneath a TBC.
Effective cross-linking strategy for graphene oxide membrane with high structural stability and enhanced separation performance
Authors: Zhang Huaitao , Hu Xuebing , Yang Boshen , Zhou Qintao
Published: March 2023

In order to solve the poor structural stability of graphene oxide (GO) membrane, a facile and effective cross-linking technology was employed to create a high-performance GO membrane. Herein, DL-Tyrosine/amidinothiourea and (3-Aminopropyl) triethoxysilane were used to crosslink GO nanosheets and porous alumina substrate, respectively. The group evolution of GO with different cross-linking agents was detected via Fourier transform infrared spectroscopy. Ultrasonic treatment and soaking experiment were conducted to explore the structural stability of the different membranes. The GO membrane cross-linked with amidinothiourea exhibits exceptional structural stability. Meanwhile, the membrane has superior separation performance, with the pure water flux reaching approximately 109.6 l·m−2·h−1·bar−1. During the treatment of 0.1 g l–1 NaCl solution, its permeation flux and rejection for NaCl are about 86.8 l·m−2·h−1·bar−1 and 50.8%, respectively. The long-term filtration experiment also demonstrates that the membrane exhibits great operational stability. All these indicate the cross-linking graphene oxide membrane has promising potential applications in water treatment.
Homogenization for time-periodic KPP reactions
Authors: Zlatoš Andrej
Published: March 2023

We prove homogenization for reaction–advection–diffusion equations with KPP reactions, in the time-periodic spatially stationary ergodic setting, and find an explicit formula for the homogenized dynamic. We also extend this result to models with non-local diffusion and KPP reactions.
DADFN: dynamic adaptive deep fusion network based on imaging genomics for prediction recurrence of lung cancer
Authors: Jia Liye , Wu Wei , Hou Guojie , Zhang Yanan , Zhao Juanjuan , Qiang Yan , Wang Long
Published: March 2023

Objective. Recently, imaging genomics has increasingly shown great potential for predicting postoperative recurrence of lung cancer patients. However, prediction methods based on imaging genomics have some disadvantages such as small sample size, high-dimensional information redundancy and poor multimodal fusion efficiency. This study aim to develop a new fusion model to overcome these challenges. Approach. In this study, a dynamic adaptive deep fusion network (DADFN) model based on imaging genomics is proposed for predicting recurrence of lung cancer. In this model, the 3D spiral transformation is used to augment the dataset, which better retains the 3D spatial information of the tumor for deep feature extraction. The intersection of genes screened by LASSO, F-test and CHI-2 selection methods is used to eliminate redundant data and retain the most relevant gene features for the gene feature extraction. A dynamic adaptive fusion mechanism based on the cascade idea is proposed, and multiple different types of base classifiers are integrated in each layer, which can fully utilize the correlation and diversity between multimodal information to better fuse deep features, handcrafted features and gene features. Main results. The experimental results show that the DADFN model achieves good performance, and its accuracy and AUC are 0.884 and 0.863, respectively. This indicates that the model is effective in predicting lung cancer recurrence. Significance. The proposed model has the potential to help physicians to stratify the risk of lung cancer patients and can be used to identify patients who may benefit from a personalized treatment option.
Plasma dynamics in a capacitively coupled discharge driven by a combination of a single high frequency and a tailored low frequency rectangular voltage waveform
Authors: Rauf Shahid , Schroeder Manuel , Korolov Ihor , Kenney Jason , Schulze Julian
Published: March 2023

Spatiotemporal dynamics in a capacitively coupled plasma discharge generated using a combination of 13.56 MHz sinusoidal voltage and 271.2 kHz tailored rectangular voltage is examined both experimentally and computationally. In the experiments, a fast-gated camera is used to measure the space and time-resolved emission at a wavelength of 750.39 nm from the Ar 2p1

→

1s2 transition. A particle-in-cell model is used to simulate the Ar plasma. The rectangular waveform is formed using 20 consecutive harmonics of 271.2 kHz, and the waveform duty cycle (DC) is varied between 5%–50%. The experiments and simulation show that excitation and argon metastable (Ar

∗

) production are primarily caused by electrons accelerated by the expanding sheath. Species generation occurs asymmetrically with more production happening adjacent to the powered electrode when the low frequency (LF) voltage is positive and vice versa. Densities of charged and excited-state neutral species decrease with increasing LF voltage due to the thinning of the plasma region and enhanced charged species loss at surfaces. At DC = 10%, the plasma responds strongly when the LF rectangular voltage switches from a small negative to a large positive voltage. Emission from the plasma and Ar

∗

production decrease considerably during this phase. When the LF voltage becomes negative again, species production and excitation remain suppressed for some time before returning to the pre-positive-pulse conditions. This reduction in plasma production is linked to the spike in electron current to the powered electrode during the positive LF voltage period, which depletes the electrons in the plasma bulk and adjacent to the grounded electrode and also raises the mid-chamber plasma potential. Plasma production suppression after the LF positive

→

negative voltage transition lasts longer at higher LF voltage and lower high frequency voltage due to lower plasma density.
Selective supply of atomic oxygen to a surface placed in room air using vacuum ultraviolet photolysis of carbon dioxide
Authors: Ono Ryo , Battulga Tuguldur , Du Hao , Komuro Atsushi
Published: March 2023

Reactive species play important roles in plasma treatments of surfaces, including polymers, metals, water, and living tissues. To elucidate the surface reaction mechanism, it is crucial to measure the effect of each type of reactive species on the surface treatment. Accordingly, we previously developed a method to selectively supply OH or O radicals to a surface placed in room air. Ar/H2O or Ar/O2 gas flowing through a quartz tube is irradiated with a vacuum ultraviolet lamp, causing photodissociation of H2O and O2 to produce OH and O. The resulting gas flows to the surface from the tube end. The O density supplied to the surface, however, is only approximately

1
×

10

12

 cm−3 according to our simulation, which is not sufficient to determine the surface treatment effect of O atoms. Therefore, in this study, a new method is proposed, supplying O atoms with a density that is two orders of magnitude higher. Specifically, CO2 gas is used as the medium to be photodissociated instead of O2 gas. The performance of this method is discussed herein using simulation results. The maximum O density supplied to the surface reaches

1
×

10

14

 cm−3 according to the simulation. Additionally, the experimental results demonstrate that the newly developed method can supply a sufficient amount of O atoms to selectively measure the effect of O atoms on the surface treatment of polypropylene (PP). In particular, the water contact angle (WCA) is considered as an index of the surface treatment. As a result, O atoms decrease the WCA of the PP surface at rates of the same order of magnitude as OH.
Characterization of a DC glow discharge in N2–H2with electrical measurements and neutral and ion mass spectrometry
Authors: Chatain Audrey , Morillo-Candas Ana Sofia , Vettier Ludovic , Carrasco Nathalie , Cernogora Guy , Guaitella Olivier
Published: March 2023

The addition of small amounts of H2were investigated in a DC glow discharge in N2, at low pressure (∼1 mbar) and low power (0.05–0.2 W cm−3). We quantified the electric field, the electron density, the ammonia production and the formation of positive ions for amounts of H2varying between 0 and 5%, pressure values between 0.5 and 4 mbar, and currents between 10 and 40 mA. The addition of less than 1% H2has a strong effect on the N2plasma discharges. Hydrogen quenches the (higher) vibrational levels of N2and some of its highly energetic metastable states. This leads to the increase of the discharge electric field and consequently of the average electron energy. As a result, higher quantities of radical and excited species are suspected to be produced. The addition of hydrogen also leads to the formation of new species. In particular, ammonia and hydrogen-bearing ions have been observed: N2H+and NH4+being the major ones, and also H3+, NH+, NH2+, NH3+, N3H+and N3H3+. The comparison to a radiofrequency capacitively coupled plasma discharge in similar experimental conditions shows that both discharges led to similar observations. The study of N2–H2discharges in the laboratory in the adequate ionization conditions then gives some insights on which plasma species made of nitrogen and hydrogen could be present in the ionosphere of Titan. Here, we identified some protonated ions, which are reactive species that could participate to the erosion of organic aerosols on Titan.
Hairpin probe assisted saturation current ratio method to determine plasma electronegativity
Authors: Singh Pawandeep , Dahiya Swati , Pandey Avnish K , Karkari Shantanu
Published: March 2023

The saturation current ratio (SCR) method is considered to be one of the simplest methods to determine plasma electronegativity in electronegative discharges using a Langmuir probe (LP). However, its accuracy is susceptible to errors incurred in the estimation of electron and positive ion saturation currents from the ampere–voltage characteristics obtained by a cylindrical LP and partly due to errors in estimating the positive ion flux at the sheath boundary. In spite of its wide use, these underlying limitations and their remedies have not been adequately investigated. In this paper, we address the above problems by involving a DC biased hairpin resonator probe to determine the plasma potential and sheath area correction factor for a cylindrical LP. These measurements are further integrated with the standard SCR method to deduce the plasma electronegativity in an oxygen plasma.
Practical analysis of different neutral algorithms for particle simulation of Hall thruster
Authors: Pan Ruojian , Ren Junxue , Mao Renfan , Tang Haibin
Published: March 2023

The modeling of neutral atoms is important for the full-particle simulations of Hall thrusters. In previous studies, researchers have developed various algorithms to model the neutral kinetics. The choice of those algorithms can influence significantly the computational speed, simulation convergence, and physical results. In this work, we perform a full-particle simulation of a typical 1 kW-class SPT-100 Hall thruster using four neutral algorithms, including the fixed-neutral algorithm (FNA), the algorithm of direct simulation of Monte Carlo (DSMC), the collisionless-neutral algorithm (CLNA), and the fluid algorithm (FA), to analyze the effects of different neutral iteration approaches on the simulation results. We found that FNA is sensitive to the initial number density of neutrals, and is difficult to converge properly, while the other algorithms not neglecting the atomic dynamics can get stable results. We count the parameters of the thruster, that is, thrust, specific impulse, and plasma density using different neutral algorithms. The time-averaged results match well with those of the experiment. However, the results differ in the time scale due to the low-frequency oscillations in Hall thrusters. We verify that the oscillations are due to the periodic change of neutrals and establish a zero-dimensional model to analyze the properties of the oscillations in the time scale. It indicates that the ratio of ion migration to neutral migration is the essential factor that significantly affects the calculation results. The model reveals that the direct neutral iteration methods, like DSMC and CLNA, can better simulate the characteristics of discharge fluctuations in Hall thrusters than the quasi-steady-state method, like FA. Finally, we proposed practical suggestions for the selection of the neutral algorithms for the SPT-100 thruster, which can also be generalized to other low- and medium-power Hall thrusters.
Plasmonic induced light trapping enhancement in silicon nanowires hybrid solar cell using indium tin oxide nanoparticles
Authors: Tunghathaithip Naraphorn , Lertvachirapaiboon Chutiparn , Sinbo Kazunari , Kato Keizo , Tungasmita Duangamol , Tungasmita Sukkaneste , Baba Akira
Published: March 2023

In this study, silicon nanowires (SiNWs) with different lengths was fabricated using the metal-catalyzed electroless etching method and used as the base structure of an inorganic semiconductor hybrid solar cell. This technique is economically attractive and allows us to easily control the physical nanostructure of the nanowires to match the light trapping mechanism of the 3D-structured hybrid solar cell. The length of the nanowire linearly increases with etching times. For solar cell fabrication, poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was used as an organic semiconductor part. The plasmonic-induced light-trapping enhancement of indium tin oxide nanoparticles (ITO NPs) and gold nanoparticles (AuNPs) mixed with PEDOT:PSS was adapted to improve solar cell performance. It was found that the hybrid solar cell, fabricated from SiNWs with 5 min-etching time, yielded the highest power conversion efficiency (PCE). Furthermore, using ITO NPs and AuNPs in a hole-transport layer of the SiNWs hybrid solar cell can improve the PCE to 50% more than the reference hybrid solar cell. The hybrid solar cell using the concentration between PEDOT:PSS and ITO NPs of 1:1/5 shows the highest PCE of 8.33%.
Semiclassical Boltzmann magnetotransport theory in anisotropic systems with a nonvanishing Berry curvature
Authors: Suh Jeonghyeon , Park Sanghyun , Min Hongki
Published: March 2023

Understanding the transport behavior of an electronic system under the influence of a magnetic field remains a key subject in condensed matter physics. Particularly in topological materials, their nonvanishing Berry curvature can lead to many interesting phenomena in magnetotransport owing to the coupling between the magnetic field and Berry curvature. By fully incorporating both the field-driven anisotropy and inherent anisotropy in the band dispersion, we study the semiclassical Boltzmann magnetotransport theory in topological materials with a nonvanishing Berry curvature. We show that as a solution to the Boltzmann transport equation the effective mean-free-path vector is given by the integral equation, including the effective velocity arising from the coupling between the magnetic field, Berry curvature and mobility. We also calculate the conductivity of Weyl semimetals with an isotropic energy dispersion, and find that the coupling between the magnetic field and Berry curvature induces anisotropy in the relaxation time, showing a substantial deviation from the result obtained assuming a constant relaxation time.
Insulator-to-metal transition in intermediate-band materials: insights from temperature-dependent transmission computations
Authors: Dong Xiao , Li Yuan , Wang Tianxing , An Yipeng , Wang Yongyong
Published: March 2023

Insulator-to-metal (I–M) transition is crucial for an intermediate-band (IB) photovoltaic material to suppress the non-radiative recombinations and improve its efficiency. Nevertheless, the mechanism and critical condition of the I–M transition is not clear yet. In this work, the critical conditions of the I–M transition in two types of Si-based IB materials were studied by combining the molecular dynamics simulations and Landauer transmission calculations. It shows that the I–M transition of the substitutional configuration of S will occur when the filled IB is expanded and merged with the conduction band, which fulfills the Mott transition theory. But this type of IB material is not a standard IB material proposed by Luque. For the substitutional configuration of N, which can be regarded as a standard IB material, the I–M transition would be occurred when the partially-filled IB is expanded and the localization of the carriers in the IB is weakened. The metallic state of the IB material is different from typical metals and they still exhibit some semiconductor properties at low temperature.
Variational approach to quantum spin liquid in a Rydberg atom simulator
Authors: Cheng Yanting , Li Chengshu , Zhai Hui
Published: March 2023

Recently the Rydberg blockade effect has been utilized to realize quantum spin liquid (QSL) on a kagome lattice. Evidence of QSL has been obtained experimentally by directly measuring non-local string order. In this paper, we report a Bardeen–Cooper–Schrieffer (BCS)-type variational wave function study of the spin liquid state in this model. This wave function is motivated by mapping the Rydberg blockade model to a lattice gauge theory, where the local gauge conservations replace the role of constraints from the Rydberg blockade. We determine the variational parameter from the experimental measurement of the Rydberg atom population. Then we compare the predictions of this deterministic wave function with the experimental measurements of non-local string order. Combining the measurements on both open and closed strings, we extract the fluctuations only associated with the closed-loop as an indicator of the topological order. The prediction from our wave function agrees reasonably well with the experimental data, with only one fitting parameter determined by measurement of Rydberg atom population. Our variational wave function provides a simple and intuitive picture of the QSL in this system that can be generalized to similar spin liquid phases in other lattice geometry.
Analysis of elastic scattering of 6Li by 90Zr near Coulomb barrier
Authors: Jena Kamala Kanta , Agarwalla Santosh Kumar , Sahu Bidhubhusan
Published: March 2023

We use a phenomenological optical potential constructed in consideration of a versatile potential developed by Joseph N. Ginocchio. The optical potential uses less number of energy-dependent parameters to analyse nuclear scattering data. We study the ratios of elastic to Rutherford differential scattering cross sections of the system 6Li + 90Zr at various energies, namely, 10.19, 11.11, 12.07, 13.95, 15.84, 17.71, 19.60, 23.36, 28.05 and 31.87 MeV in the centre-of-mass system. The study of angular distributions is performed in a wide angular range. Our theoretical calculations explain the experimental results and follow breakup threshold anomaly phenomenon near the Coulomb barrier. We discuss the variation of reflection function |S
l
| with ‘l’ for each contributing partial wave and calculate reaction cross section for the system against the projectile energy 31.87 MeV with permissible error.
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

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

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

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

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

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

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

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

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

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

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

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

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

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.