bluuebunny/crossref_metadata_2025_split huggingface dataset:
Python programming code for stellar photometry in astrophysics teaching on a cloud computing service
Authors: Krittinatham W , Kaewkhong K , Emarat N 
Published: February 2023

Abstract
Nowadays, there is various software used for both education and astronomy research. For photometry, licensed software and high-performance computer operating systems are required, which is a fund limitation for some schools in Thailand. Thus, in this article, we develop and present the Demonstration Photometry Scripts for Astrophysics Teaching (DPSAT version 1.0). The program is designed to work on cloud computing services via internet browsers to avoid hardware and operation requirement pain points. The DPSAT is programming on flexible, low-cost, on-trend language, Python, and Jupyter Notebook online editor. In advance, our new code supports the home-use image or video file format, i.e., jpg, png, or mp4. Thus, it will be more accessible for teachers and students who do not have standard astronomical instruments. The DPSAT measures the stellar light intensity from the time-series still-images or video files from a smartphone or other digital devices. The code can extract video files into sequenced still images, then transform the RGB color space images into greyscale. The light intensity signal of selected pixels is counted with a simple aperture method in time series. It shows the results, for example, the mean signal, standard variation, measured signal as light intensity versus time, and image of light sources. This will be fruitful for low-cost and easily accessible teaching of astrophysics subjects.
Fractional Little-Parks effect in hybrid superconductor-ferromagnet proximity cylinders
Authors: Chamnan N , Nisaisue C , Krunavakarn B 
Published: February 2023

Abstract
We argue that the Little-Parks effect, i.e., the oscillations of the superconducting critical temperature Tc
as a function of the magnetic flux threaded the superconducting cylinder, exhibits the feature of the fractional quantized flux when a ferromagnetic metal filled in the thin-walled superconducting shell, which caused by the exchange interaction. Our analysis is based on the transport-like proximity effect theory in the diffusive regime of Takahashi-Tachiki and shows explicitly that the extremum of Tc
in the vortex state L corresponds to the fractional values of fluxoid, and in particular the fractional flux quantum occurred at the L = 1 vortex state.
First-principles prediction of configurational order-disorder phase transition in Mo2(Ti1−x
V
x
)C2 MXene alloys
Authors: Atthapak Chayanon , Pakornchote Teerachote , Bovornratanaraks Thiti , Maezono Ryo , Ektarawong Annop 
Published: February 2023

Abstract
We investigated the thermodynamic stability of Mo2(Ti1−x
V
x
)C2 MXenes (MTVCs), using the first-principles calculation based on density functional theory and cluster-expansion formalism. Our results suggest that Mo atoms prefer to substitute in the outer metal layers of MTVCs, and such occupying behavior is a crucial factor that determines the thermodynamic stability of MTVCs. On the other hand, Ti and V atoms residing in the inner metal layer of them are predicted to weakly interact with each other and their atomic configuration has a minimal impact on the stability of MTVCs. The transition temperatures between configurationally ordered and disordered phases of MTVCs have been predicted, and the possible existence of configurationally disordered MTVCs has also been discussed.
The temperature dependent surface critical magnetic field (Hc3) of K0.73Fe1.68 Se2 superconductor by semi-anisotropic two band Ginzburg-Landau approach
Authors: Meakniti S , Changjan A , Udomsamuthirun P 
Published: February 2023

Abstract
In this study, we used a two-band Ginzburg-Landau technique to investigate the surface critical magnetic field (Hc3
) of magnetic superconductors, with the first band being an anisotropic superconductor and the second band being an isotropic superconductor. Following the calculation of the 1st Ginzburg-Landau equation, a surface critical magnetic field and its temperature dependent surface critical magnetic field were solved analytically using the variation method. Based on Changjan and Udomsamuthirun’s temperature dependency model, we discovered that fits best with experimental data of K0.73Fe1.68 Se2 superconductor, vicinity of the critical temperature.
Classification of superconducting transition temperature over 150K of metal polyhydrides using support vector machine
Authors: Imchitr V , Pinsook U 
Published: February 2023

Abstract
The search for room-temperature superconductors have shed light on metal polyhydrides as their superconducting transition temperature (TC) vary from a few kelvins to near-room temperatures. One major drawback in the quest for hydrogen-based superconductors is that the calculation of TC through the electron-phonon spectral function consumes large amount of time and computational resources. Here we propose a method of using the support vector machine (SVM) to classify the ranges of TC of the metal polyhydrides without actual calculation of the electron-phonon spectral function. The input variables are chosen based on the effect of hydrogen atoms and the electron localization function (ELF). These set of features can be obtained quickly from the electronics simulations, compare with the actual spectral function calculations. We found that the SVM can classify the superconductors with accuracy over 80 percent with respect to all the metal polyhydrides in the dataset. Our goal of this work is to help screen for the high value of TC of the hydrogen-based compounds, and reduce the time required for the direct calculations of TC.
Structural, mechanical properties and corrosion performance of multilayer Ti doped-DLC/Ti films deposited on low-carbon steel
Authors: Rittihong U , Tunmee S , Supruangnet R , Chingsungnoen A , Poolcharuansin P , Singhapetcharat T , Kiattikomol P , Eknapakul T , Nakajima H , Songsiriritthigul P 
Published: February 2023

Abstract
In this work, the successful preparation of the multilayer Titanium doped diamond-like carbon/Ti (Ti-DLC/Ti) films deposited on low-carbon steel (CS) using hybrid magnetron sputtering (MS) and plasma-enhanced chemical vapor deposition methods has been reported. The Ti and Ti-DLC films were alternately deposited on the CS substrate of up to 4 stacks with an average deposition rate of 16.4±1.7 nm/min and 15.1±1.5 nm/min, respectively, yielding a total thickness of up to 1703 nm. Raman spectroscopic analysis revealed a gradual increase in the I
D/I
G ratio with an increase in Ti layer numbers. Both XPS and NEXAFS results indicate an increase in the C-sp
2 content by increasing the number of Ti layer, which may influence on the hardness reduction. The adhesive properties were found to be improved by adding the number of Ti interlayers between the CS substrate. Moreover, the thicker multilayer films exhibit progressive homogeneity resulting in better corrosion resistance.
Effects of compression on magnetic properties of MnBi prepared by liquid-phase sintering
Authors: Juntree P , Eknapakul T , Pinitsoontorn S , Songsiriritthigul P 
Published: February 2023

Abstract
In this work, the Mn and Bi mixture prepared with and without compression were sintered in a vacuum at 325°C and cooled down naturally to obtain low-temperature phase MnBi. For non-compressed samples, the MnBi content increases with sintering time which could be described by the diffusion process. The average maximum energy product ((BH)max) values were 3.67, 3.05, and 4.77 MGOe for MnBi sintered for 24, 48, and 96 hr, respectively, consistent with their phase identifications. For the compressed samples, the MnBi phase is significantly low in the 24-hr sintered samples compared to the samples sintered for 48 and 96 hr. This resulted in an average (BH)max of 0.43, 3.90, and 3.23 MGOe for the compressed samples sintered for 24, 48 and 96 hr, respectively. The results suggest that compression of the Mn and Bi mixture affects the flow of liquid Bi during sintering and, thus, hinders the formation of MnBi. The effects of the compression were reduced for the prolonged sintered samples, suggesting changes in the internal structure as the sintering proceeded.
Synchrotron Radiation Fourier Transform Infrared (SR-FTIR) spectroscopy in exploring crosslinked chitosan-rice husk bio-composites by gamma irradiation
Authors: Aim-O P , Pamungkas N S , Nawong S , Thamrongsiripak N , Thongphanit S 
Published: February 2023

Abstract
Chitosan biomaterials have widely been used to absorb heavy metals from wastewater and aquatic system due to their low residue generation and the ability to recycle and reuse adsorbents. The chitosan polymer’s high abundance of amino groups also allows for numerous chemical changes to improve its adsorbent characteristics and adsorption capacity. This work synthesized the bio-composite from rice husk and coated it with chitosan solutions. The gamma irradiation had been applied to create the crosslinking chitosan to join two or more intermolecular or intramolecular by a covalent bonding that could give a more rigid structure and potentially a better-defined shape of the material. The Chitosan-Rice Husk bio-composite was irradiated using gamma radiation at a dose of 50, 100, 200, and 400 kGy. Synchrotron Radiation Fourier Transform Infrared (SR-FTIR) Spectroscopy results revealed the induced crosslinking formation of bio-adsorbents after irradiation. The surface topography and composition of samples were demonstrated by using SEM. The natural bioproduct or waste bioproduct is a new promising adsorbent for the removal of heavy metals from industrial wastewater.
Design of dipole magnets for Siam Photon Source II
Authors: Sunwong P , Klinkiew S , Leetha T , Prawanta S , Singthong P , Songsiriritthigul P 
Published: February 2023

Abstract
Two types of dipole magnets are designed for the storage ring of Siam Photon Source II, the second synchrotron light source in Thailand. Magnetic field at the magnet center is 0.87 T, which bends a 3.0 GeV electron beam with the bending radius of 11.532 m and consequently the synchrotron radiation is generated. The first type of dipole magnet is a standard dipole with the magnet gap of 36 mm. The other type is designed for Infrared (IR) beamline with the larger magnet gap of 59 mm to accommodate a wide opening angle of IR radiation. The magnets are designed such that the operating current is the same while the turn number of magnet coils and the magnet gap are allowed to be different. Therefore, a single power supply can be used to excite all dipole magnets in the storage ring which will be connected in series. Magnet modelling and magnetic field calculation are performed in Opera-3D. The magnet poles are shimmed near the edges to improve magnetic field homogeneity to be within the requirement of 2×10−4 within the good field region. Mechanical analysis of magnet structure is performed in SOLIDWORKS and ANSYS where the maximum deformation of 18 - 23 µm is found at the magnet pole and the first-mode natural frequency is higher than 200 Hz.
Considered design and radiation calculation for a compact THz coherent radiation source
Authors: Jummunt Siriwan , Chanwattana Thakonwat , Chunjarean Somjai , Junthong Nawin , Klinkhieo Supat , Pulampong Thapakron , Sunwong Prapaiwan 
Published: February 2023

Abstract
Since the light obtained from the Siam Photon Source (SPS) in Thailand is the high-intensity radiation in only the region of the infrared (IR) to high-energy X-rays, it has great attention in many areas of scientific research and industrial development. In order to increase in the number of users and applications, the terahertz (THz) region covering the frequency range from 0.1 to 10 THz needs to be fulfilled. Therefore, a compact accelerator based free-electron laser or coherent radiation is particularly interesting for providing an intense THz radiation. A 1.6-cell photocathode RF gun is used as an electron source to generate a high-brightness electron beam. The energy of electron beam can be raised up to meet the target of 30 MeV in a linear accelerator (Linac) before moving to a chicane bunch compressor. The THz radiation is produced when a short bunch electron beam propagates through an undulator. In order to achieve the intense narrow-band THz coherent radiation at tunable frequencies between 0.5 THz and 5.0 THz with MW peak power, a THz radiation source needs to be studied and developed. Design of high-power THz radiation source is described in this paper.
Fabrication and development of neutron shielding materials based on natural rubber and boron carbide
Authors: Saenpoowa Jittinun , Ruksakulpiwat Chaiwat , Yenchai Chadet , Kobdaj Chinorat 
Published: February 2023

Abstract
Neutron shielding materials were fabricated based on natural rubber (NR) and boron carbide (B4C) as their main components. Natural rubber, which is abundant in hydrogen, can lower the energy of a neutron. Boron carbide could be utilized as a neutron shielding material due to its high boron content. The shielding materials were fabricated with boron carbide concentrations of 0, 20, 40, 60 parts per hundred rubber (phr), and 50 wt%. Each sample has been fabricated with thicknesses of 5, 10, 15, 20, and 24 mm. The fabricated materials were examined for mechanical and neutron attenuation tests. The Am/Be at the Radiation Measurement Laboratory at the Nuclear Engineering Department, Faculty of Engineering, Chulalongkorn University, was used as a neutron source. The results show that boron carbide has the effect of reducing the toughness while increasing the hardness of NR composites. The NR sample of 50 wt% in boron carbide allows only 14.1% of neutron transmission according to fast neutron attenuation tests, which is similar to that of a sample of the commercial product obtained from a Japanese company. Our findings will later be compared to those of a Monte Carlo N-Particle (MCNP) transport code.
The effect of AGN feedback on shape of dark matter haloes
Authors: Naree Netipon , Muanwong Orrarujee 
Published: February 2023

Abstract
Feedback from active galactic nuclei (AGN) plays an important role on the formation and matter distribution in haloes. We investigate the effect of AGN feedback on shape of dark haloes formed in the EAGLE simulations, and trace the evolution. We select three mass ranges of haloes; low (1011 − 1011.5M⨀), intermediate (1012 − 1012.5M⨀) and high (1013 − 1014.5M⨀) mass, the last range is of small cluster scale. We find the median profile of triaxiality in each mass range at three redshifts (0, 0.27 and 0.87) from two simulations, with and without AGN. The difference of triaxiality in both simulations of low mass haloes at all redshifts is relatively not apparent while the most apparent difference exhibits in high mass haloes. The shape of dark matter haloes in the simulation with AGN is more prolate than that in the simulation without AGN. We also use the ratio between blackhole and dark matter mass, relating to AGN energy output relative to halo potential depth to explain the result. Since the mass ratio between blackhole and dark matter mass in the high and intermediate mass is much larger and extends to the larger radii than that of low mass haloes, the difference is more prominent out to the outer region. We conclude that the shape of dark matter haloes of small cluster scale can be affected by AGN feedback through the evolution. However, this study focuses on an extreme AGN feedback model with a relatively small dynamical range.
Investigation of the periastron shift of star orbit in Hernquist potential
Authors: Sukon B , Chainakun P , Worrakitpoonpon T 
Published: February 2023

Abstract
Understanding of the dynamics of stars around a strong gravitational body such as a supermassive black hole at the centre of galaxies is still incomplete. There is strong evidence suggesting that the orbits of stars in the galactic centre do not follow the Kepler’s laws. In this work, we study the periastron shift from the classical gravitational effect. We select the Hernquist potential function representing a galactic component to examine the rate of change of periastron angular position of a test star. We employ the numerical method to track the orbital dynamics of the test star in that potential. First of all, the periastron shift of the test star is noted and it evolves in the retrograde way. We find that the precession rate varies considerably with the initial speed of the star. In conclusion, we speculate that this effect is non-negligible and it should be accounted when considering the motion of stars in the galactic centre.
Splitting of the atomic hydrogen 21-cm line induced by gravitational waves from a supermassive black hole binary
Authors: Wanwieng N , Chattrapiban N , Watcharangkool A 
Published: February 2023

Abstract
We investigate the characteristic of the hyperfine splitting of a ground-state hydrogen atom subjected to a field of a gravitational wave. In our consideration, hydrogen atoms are in the source’s local wave zone. The interaction between the atoms and the gravitational wave induces the shifts of some energy levels in the hyperfine structure, computed by the first-order perturbation theory. The splitting of energy levels leads to more than one hyperfine transition. Our analysis suggests that a gravitational wave emitted by supermassive black hole binaries could be strong enough to induce a significant effect on the hyperfine splitting. This radio-wave spectrum provides the gravitational-wave signature and thus offers a way of identifying the merger of supermassive black hole binaries.
Machine learning application for dark matter - background classification in JUNO experiment
Authors: Siripak J , Yan Y , Sawangwit U , Sangungsuk N 
Published: February 2023

Abstract
Jiangmen underground neutrino observatory (JUNO) has a potential to indirectly detect dark matter (DM), observing neutrino events from annihilations of DM trapped by the gravitational force in the solar core. Weakly interacting massive particle (WIMP) DM candidate with mass > 4 GeV has significant solar capture rate. In this work, we simulate JUNO neutrino events from the most dominated WIMP annihilation channel,

τ

τ

−

. Given the high-energy neutrinos from massive WIMPs, we extend the neutrino-nucleon interactions in the detector to include quasi-elastic (QE) and deep inelastic scatterings (DIS). The most challenging background events in the energy range above 100 MeV is the atmospheric neutrinos (atmo). The pulse shape discrimination (PSD) method is usually applied to distinguish between DM and atmo. In this work, we apply machine learning (ML) techniques to distinguish between the background (BG) atmo and DM neutrino events. We found that the random forest algorithm gives the best results. Using ML, the accuracy of DM-atmo events classification is 93.8% while similar f1-score could be achieved. On the other hand, only 78.1 % accuracy is obtained using conventional PSD with linear regression (LR). The upper limit for spin-dependent DM-proton cross-section

σ

χ
p

S
D

with the applied ML is 5.84 × 10−40 cm2 for a 10 GeV WIMP DM which is an improvement over the sensitivity of the LR method of by a factor of ∼ 2.8x.
The scientific capabilities of the Evanescent Wave Coronagraph EvWaCo
Authors: Ridsdill-Smith M , Berdeu A , Alagao M A , Buisset C , Awiphan S 
Published: February 2023

Abstract
The Evanescent Wave Coronagraph, EvWaCo, is an in-development prototype coronagraph, designed for use on the 2.4m Thai National Telescope (TNT), in the R and I-band filters. This work examines the astronomical capabilities of EvWaCo using the results from Fourier-analysis simulations. Fourier optics simulations were applied to the EvWaCo prototype to analyse its performance, combining different sources of contrast degradation that will be present in the system. The simulations used for the main analysis assume a good night at the Thai National Observatory (TNO) and include the fitting error, aliasing, measurement noise and lag, providing a radially averaged contrast curve. From the contrast curve, the detection limit, as defined by a minimum signal to noise ratio of 5 for a typical observation time, can be calculated for different primary star magnitudes. The relative fluxes of various binary stars, with a range of spectral classes and separations, were modelled allowing comparison to the EvWaCo detection curves. The photon-noise limited detection curves provide a theoretical baseline for the performance that will be achieved with EvWaCo; they, therefore, give an indication of the types of objects EvWaCo can observe. Along with a broader discussion of observable objects, a number of known binary systems are suggested for observations on the TNT using EvWaCo.
Unidirectional gradient of galactic cosmic ray intensity at different cut-off rigidities and solar magnetic polarities
Authors: Wuttiya C , Yeeram T 
Published: February 2023

Abstract
Energetic charged particles known as Galactic cosmic rays (GCRs) are mostly protons originating from supernova remnants. The solar wind modulates the GCR intensity near-Earth along the solar cycles (SCs) in association with the heliospheric magnetic field (HMF). GCR intensity as observed by the neutron monitor at low, medium, high cut-off rigidities (Pc
) is employed to calculate the South-North (SN) asymmetry of GCR densities (n) of different magnetic polarity states (A) of the HMF. The study covered SCs 22/23, 23/24 and 24/25, during negative and positive states (A < 0 and A > 0). We used the modified correction for secular changes in n to determine the SN asymmetry of n (δnS−N
/n) with respect to the heliospheric current sheet (HCS), a wavy structure dividing the northern and southern HMFs. We found anti-correlation of corrected tilt angle of HCS [α] for Earth’s excursions in helio-latitude

Δ

α

N
−
S

E

with the corrected δnS−N/n, particularly during A < 0 epoch (2004-2008) and A > 0 epoch (2015-2019 not 1996-1998). The results indicate that HCS drift is crucial for asymmetric modulation and latitude gradient of GCR in both epochs. The asymmetric latitudinal gradient [G
⊥] shows strong positive correlation to the consistency between the corrected δnS−N/n and

Δ

α

N
−
S

E

for all epochs and Pc
.
Design and analysis of Hollow-core fiber with anti-resonant structure for Ethylene detection
Authors: Joonmasaa Kwanjira , Sangtawesin Sorawis , Meemon Panomsak , Talataisong Wanvisa 
Published: February 2023

Abstract
An optical fiber for mid-infrared (mid-IR) guidance has long attracted great interest due to its wide range of applications especially in gas sensing. Ethylene gas is one of an important gas, which release from the fruit and flower, owing to their ripening process. Thus, the controlling and detection of ethylene gas is of interest for the storage and exportation of fruits and flowers. Gas detection using the hollow-core optical fiber (HCF) is a promising technique due to it intrinsic micro-channel structure that allows the gas to flow through the HCF for detection propose. Here, a hollow-core anti-resonant fiber (HC-ARF) is designed and optimized for mid-IR guidance for the purpose of ethylene detection. The HC-ARF includes 6 inner tubes which is optimized to achieve a low confinement loss at a wavelength of 3.2 µm (ethylene absorption wavelength). The simulation result shows that a confinement loss of 2 dB/m at the wavelength of 3.2 µm can be achieved when the fiber core diameter is 128 µm and the thickness and the diameter of inner tubes are 2 µm and 92 µm, respectively.