bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of nano-indentation depth on the elastic–plastic transformation of 6H-SiC simulated
Authors: Wu Nanxing , Jiang Peng , Zhang Huiling , Feng Xiaoyu , Zheng Qi
Published: February 2023

To investigate the effect of nano-indentation depth on the elastic–plastic transition mechanism of 6H-SiC, the loading process of nano-indentation on a 6H-SiC⟨0001⟩ crystal surface is analyzed by using the molecular dynamics method. Diamond indenters and 6H-SiC amorphous nanolayers are constructed; Tersoff and Vashishta potential functions are established to describe the interactions between atoms; and simulated environmental factors, such as relaxation conditions, ensemble, and loading speed, are optimized. The stress distribution and internal deformation characteristics are analyzed by combining load–displacement curves, radial distribution curves, dislocation nucleation, and their evolutive processes. The load–displacement curve deviates from the theoretical value at a depth of 3.8 nm and enters the elastic to plastic transition phase, where the shear stresses generated by friction on the contact surfaces cause the atoms on the stacked layers in the elastic phase to move in a directional manner and form dislocations: edge-type dislocations connecting the two layer dislocations and horizontal spiral dislocations. The plastic deformation phase starts at a depth of 5.9 nm, the atoms keep migrating and reorganizing, the original dislocation rings break to form incomplete dislocations, and the new dislocations formed by the combination of partial edge-type dislocation rings expand internally until fracture. The formation and expansion of dislocations contribute to the elasto-plastic transformation of 6H-SiC, and amorphous states are found to be involved in the deformation process at both the indentation contact surface and the deformation layer. Moreover, there are differences in the direction of dislocation expansion due to the inhomogeneous stress distribution at the contact surface.
Carbon nanotube-based double-layer microporous cathode for micro-direct methanol fuel cell
Authors: Zhao Zhengang , Wang Jiankun , Liu Qingchan , Wang Ziteng , Zhang Jiahong
Published: February 2023

The micro-direct methanol fuel cell (μDMFC) has the advantages of high energy density, high conversion efficiency, and simple structure, which brought vast application prospects in portable devices. However, some shortcomings still exist, such as low catalyst utilization and power density. This paper proposes a new cathode electrode structure for the μDMFC. The structure consists of a multi-walled carbon nanotube layer and a cathode double microporous layer (CD-MPL) prepared from carbon powder. The outer microporous layer (OMPL) is composed of multi-walled carbon nanotubes (MWCNTs), Nafion solution, and carbon powder, and the inner microporous layer (IMPL) is composed of carbon powder and polytetrafluoroethylene (PTFE). The experimental results show that the maximum power density of the μDMFC with a CD-MPL (CD-μDMFC) is 42.8 mW/cm2, which is 31.6% higher than that of the μDMFC with a cathode single microporous layer (CS-μDMFC). The pore size distribution of the OMPL of the CNT is measured by the mercury intrusion method. It can be seen that the distribution of pore size is wider and there are more pores with larger pore sizes, which are more conducive to the utilization of catalysts. The discharge experiment of the cell shows that the CD-μDMFC shows high discharge performance and fuel utilization at different concentrations. The double microporous layer (MPL) structure increases the porosity and pore range, broadens the three-phase interface for the reaction, and allows the catalyst to have more attachment sites. The existence of MWCNTs improves the conductivity and mass transfer capacity of the cathode.
A hybrid learning framework for multi-modal facial prediction and recognition using improvised non-linear SVM classifier
Authors: SaiTeja Chopparapu , Seventline J. B.
Published: February 2023

Multi-modal classification plays a vital role for the real-time applications since most of the conventional models are independent of homogeneous features with single classifier. In addition, traditional directional gradient descriptors are difficult to find the heterogeneous features on different biometric classification. Feature extraction, segmentation, and multi-modal classification are the essential key factors that improve the true positive rate, error rate, and false positive rate of human-based recognition systems. In this work, a hybrid ensemble-based feature selection ranking measure, hybrid segmentation, and ensemble multi-class multi-modal classification framework on different biometric features is designed. Experimental results show that the proposed multi-class multi-modal ensemble classification framework has better optimization in terms of false positive rate, error rate, and precision than the conventional homogeneous local gradient feature extraction-based classification models on different features.
Combinatorial dependence of magnetic printing characteristics in double magnet master media for energy-assisted magnetic recording
Authors: Komine Takashi
Published: February 2023

In this study, the combinatorial dependence in double magnet master for energy-assisted magnetic recording was investigated by the micromagnetic framework. Four kinds of master media, which are soft single magnet (SSM), hard single magnet (HSM), soft double magnet (SDM) and hard double magnet (HDM), were compared. Comparing single magnet and double magnet master media, more adequate combination of double magnet master media was discussed. The HSM, SDM, and HDM master media can write line/space (L/S) pattern with bit length of 20 nm, while the double magnet master media can clearly print L/S patterns comparing with single magnet in case of 10 nm. For higher coercivity EAMR media, the larger printing field causes larger recording field difference by utilizing SDM master media while in case of HDM the recording field difference is almost constant even if the printing field increases. As a result, since the recording field difference of SDM becomes larger than that of HDM as the printing field strengthens, thus, SDM master media can write the servo signals onto higher coercivity EAMR media. It was concluded that it is important for the low coercivity parts of double magnet master media to have a larger saturation magnetization due to enhancement of large recording field difference.
Magnetic characterization of La3+ and Li1+ co-substituted M-type strontium hexaferrite
Authors: Kim Chul Sung , Yoon Sunghyun
Published: February 2023

Effects of stoichiometric La3+–Li1+ co-substitution on magnetic properties of M-type strontium hexaferrites Sr1-xLaxFe12-x/2Lix/2O19 (x = 0, 0.25, 0.4, 0.5, 0.6) have been studied by using crystallographic and magnetic measurements. Samples were prepared thru conventional ceramic technique and their powder X-ray diffraction profiles were checked by the Rietveld method using GSAS package. Field emission scanning electron microscopy images show that lithium addition derives the enhanced degree of grain separation, which significantly affects the coercivity and anisotropy constant as examined by vibrating sample magnetometer measurement. 57Fe Mössbauer spectra of the samples show that Li1+ ions preferentially occupy the 2a sites, which causes the decrease of MS with lithium addition.
Torque analysis of a permanent magnet synchronous motor using flux densities in air gap
Authors: Lee Sangjin , Kim Changhwan , Choo Yongha , Yun Gyeonghwan , Lee Cheewoo
Published: February 2023

Permanent magnet synchronous motors (PMSMs) having high power density and high efficiency are rigorously researched in various premium applications. Among PMSMs, many studies have been conducted on interior permanent magnet synchronous motors (IPMSMs) to improve torque ripple, but its accurate estimation is not straightforward. Therefore, a six-pole nine-slot (6p/9s) IPMSM is adopted as a base model due to its popularity in academia and industries, and other two pole/slot combinations (8p/12s and 10p/15s) are additionally selected to investigate the influence of a pole/slot combination on torque ripple. Torque performance is easily identified by analyzing tangential force due to their direct proportional relation. In this paper, magnetic flux densities in radial and tangential direction are systematically analyzed since tangential force is determined by the product of the two magnetic flux densities. The modification of a stator pole regarding its tip thickness is chosen as a key parameter in 6p/9s IPMSM. The thickness of a stator pole tip opposite to the direction of spin is more critical in torque ripple improvement. It is verified that the proposed method is sufficient for accurate torque prediction.
Effect of laser power on structural and magnetic properties of anisotropic Nd-Fe-B film magnets prepared by PLD method
Authors: Yamashita A. , Hanada S. , Yanai T. , Nakano M. , Fukunaga H.
Published: February 2023

Anisotropic Nd-Fe-B film magnets are applied to miniaturized electronic devices and MEMS (Micro Electro Mechanical Systems) devices have been prepared by the sputtering method. However, the thickness of each film is mainly less than 20 μm. We have already fabricated anisotropic rare-earth film magnets by pulsed laser deposition (PLD) technique. In this study, an investigation has been carried out on increasing laser beam power for a high deposition rate. Although the thickness of the films increases as laser power increases, it is suggested that the residual magnetic polarization ratio and coercivity values of anisotropic Nd-Fe-B film magnets are not allowed to deteriorate with increasing laser power or deposition rate. These results suggest that we have the facility in obtaining perpendicularly anisotropic Nd-Fe-B thick-film magnets using the PLD method.
Distribution and evolution of surface charges in nanosecond pulsed dielectric barrier discharge under the quiescent air and airflow
Authors: Wang Xiao , Yan Hui-Jie , Wang Yu-Ying , Yu Si-qi , Li Ting , Song Jian
Published: February 2023

The surface charges in nanosecond pulsed dielectric barrier discharge under quiescent air and airflow are detected based on the Pockels effect of electro-optical crystals. In quiescent air, it is found that the surface charge spot propagates and moves in a certain direction due to the combination of the transverse electric field and the thermal accumulation during dozens of consecutive discharge cycles. However, the position of the surface charge spot remains fixed throughout a single discharge cycle (0.83 ms). At the same time, the noticeable decay of surface charges emerges in the above time scales. Furthermore, when the airflow is introduced into the discharge gap, the propagation and movement of surface charges are accelerated. With the increase of airflow velocity, the discharge transforms from a filamentary mode to a diffuse mode, and the distribution of surface charges varies from discrete to uniform. The transition point of the discharge state and charge distribution corresponds to the airflow velocity of 10 m s−1. The airflow accelerates the decay of surface charges, resulting in the shrink and dispersion of surface charges, which is considered to be the fundamental reason for the airflow’s potential to improve discharge uniformity. The inherent mechanism for achieving uniform discharge is revealed in this study.
An organ deformation model using Bayesian inference to combine population and patient-specific data
Authors: Rørtveit Øyvind Lunde , Hysing Liv Bolstad , Stordal Andreas Størksen , Pilskog Sara
Published: February 2023

Objective. Organ deformation models have the potential to improve delivery and reduce toxicity of radiotherapy, but existing data-driven motion models are based on either patient-specific or population data. We propose to combine population and patient-specific data using a Bayesian framework. Our goal is to accurately predict individual motion patterns while using fewer scans than previous models. Approach. We have derived and evaluated two Bayesian deformation models. The models were applied retrospectively to the rectal wall from a cohort of prostate cancer patients. These patients had repeat CT scans evenly acquired throughout radiotherapy. Each model was used to create coverage probability matrices (CPMs). The spatial correlations between these estimated CPMs and the ground truth, derived from independent scans of the same patient, were calculated. Main results. Spatial correlation with ground truth were significantly higher for the Bayesian deformation models than both patient-specific and population-derived models with 1, 2 or 3 patient-specific scans as input. Statistical motion simulations indicate that this result will also hold for more than 3 scans. Significance. The improvement over previous models means that fewer scans per patient are needed to achieve accurate deformation predictions. The models have applications in robust radiotherapy planning and evaluation, among others.
Scattering properties of Bessel beams on metal particles
Authors: Wang Zhe , Wei Qun , Zhang Shu , Li Linqian , Hu Mingwei , Li Renxian
Published: February 2023

Based on Generalized Lorenz-Mie Theory (GLMT), the scattering phenomenon caused by Bessel beam irradiation on metal particles is studied. The order and polarization mode of Bessel beam, as well as the influence of the size of metal particles on the total intensity distribution of the light field around metal particles are investigated by using the software simulation calculation. The results show that for spherical metal particles of the same size, the higher order Bessel beam is more likely to bypass the metal particles in the forward propagation, while the lower order Bessel beam bypassed the particles in the propagation is related to the beam polarization mode. The results have potential applications in microscopy super-resolution imaging and detection of tiny particles.
Two dimensions modelization of radiative exchange in polar bears’ fur
Authors: Rchida Lamiaâ , Rattal Mourad , Bahou Younouss , Mouhsen Azzeddine , Harmouchi Mohamed , El Mostafa Oualim
Published: February 2023

To survive in the Arctic, polar bears must have excellent thermal insulation to endure high winds and extreme cold. As a result, mastering the mechanisms responsible for arctic animals’ superior radiative insulation will be aided by knowing the radiative exchanges in their fur. A mathematical model was created for this purpose by integrating the coat’s hairs into thin sheets. Then, using MATLAB, a computer simulation was run to determine the temperature variation as well as the energy flow between the external environment and the polar animal’s body through the hairs. With such thermal qualities, the proposed model will have a good insulating capacity, allowing it to recreate the structure of polar bear hair and incorporate it into real-world applications, such as serving as just a thermal insulator for keeping the heat in a house during the winter.
Testing gravity with gravitational waves × electromagnetic probes cross-correlations
Authors: Scelfo Giulio , Berti Maria , Silvestri Alessandra , Viel Matteo
Published: February 2023

In a General Relativistic framework, Gravitational Waves (GW) and Electromagnetic (EM) waves are expected to respond in the same way to the effects of matter perturbations between the emitter and the observer. A different behaviour might be a signature of alternative theories of gravity. In this work we study the cross-correlation of resolved GW events (from compact objects mergers detected by the Einstein Telescope, either assuming or excluding the detection of an EM counterpart) and EM signals (coming both from the Intensity Mapping of the neutral hydrogen distribution and resolved galaxies from the SKA Observatory), considering weak lensing, angular clustering and their cross term (L × C) as observable probes. Cross-correlations of these effects are expected to provide promising information on the behaviour of these two observables, hopefully shedding light on beyond GR signatures. We perform a Fisher matrix analysis with the aim of constraining the {μ
0, η
0, Σ
0} parameters, either opening or keeping fixed the background parameters {w
0, w
a}. We find that, although lensing-only forecasts provide significantly unconstrained results, the combination with angular clustering and the cross-correlation of all three considered tracers (GW, IM, resolved galaxies) leads to interesting and competitive constraints. This offers a novel and alternative path to both multi-tracing opportunities for Cosmology and the Modified Gravity sector.
The 17th Siam Physics Congress : Carbon Neutrality (SPC2022)
Authors: Laosiritaworn Y , Aukkaravittayapun S , Tawkomnoy J , Soonthornthum B
Published: February 2023

The 17th Siam Physics Congress (SPC2022) was successfully held during 22-24 June 2022, co-hosted by the Thai Physics Society and the Suranaree University of Technology. Since the COVID-19 situation have been getting better, and to motivate more collaborative academic environment, the congress was organized to be a 100% on-site meeting at Khao Yai Convention Center (KYCC) in Nakhon Ratchasima (Thailand) during June 22-24, 2022.

List of Track, Organizing Committee, Scientific Committee, Plenary Speaker, Organizing Institutions, Sponsors are available in this Pdf.
Impact of solvent ratio on diphenyl oxalate chemiluminescence
Authors: Dangudom K , Khampa W , Boonyaras P
Published: February 2023

This research studied the effect of solvent ratio on chemiluminescence widely applied in glow sticks using dichloromethane and ethyl acetate as solvents. The fluorescent solution, as a mixture of diphenyl oxalate solvent and fluorescent dye rhodamine B, was stimulated by a 405 nanometre laser for fluorescent spectrum measurement before the chemiluminescence experiment. The fluorescent solution concentration and solvent ratio were varied. For the chemiluminescence experiment, diphenyl oxalate was dissolved in the solvents and combined with rhodamine B that interacted with a mixture of hydrogen peroxide and acetonitrile, resulting in chemiluminescence. The duration and intensity of light were measured by a photodiode detector. Results revealed that the concentration and solvent ratio of the fluorescent solution impacted the fluorescent spectrum due to opacity and solubility. Increasing ethyl acetate and decreasing dichloromethane gave a longer duration of light. The intensity of light in some ratios alternated high and low. Light emitted for a long time at high intensity is suitable for applications. Solvent ratios at 3:7 and 5:5 (1:1) gave better results than the other samples.
Assessment of radon concentration of vegetables and fruits in local markets in Muang Nakhon Phanom Municipality, Thailand
Authors: Pookamnerd Y , Atyotha V , Thopan P , Poochada W
Published: February 2023

Aim of this research is a hazards assessment of radon concentration and effective radium content were estimated in 24 vegetables and 9 fruits samples that were collected randomly from local markets in Muang Nakhon Phanom Municipality, Thailand by active detecting method (RAD 7). The results showed that radon concentrations in vegetables were in the range of 6.27 – 45.11 Bq/m3, the mean was 21.32±2.36 Bq/m3and radon concentrations in fruits were in the range of 12.11 – 53.19 Bq/m3, the mean was 27.47±2.81 Bq/m3, respectively. All values of radon concentrations for vegetable and fruits in these study were found to be well below than the international standard level of radon concentration 190 Bq/m3recommended by the EPA. These results were also used to calculate the average effective dose equivalent (EDE) of radium from vegetables and fruits, calculation was 0.034 µSv/y, this is lower than the effective dose equivalent for the standard value of 1.3 mSv/y recommended by the EPA. This study show that vegetables and fruits were found to be safe from radon contamination.
Electrolyte drink analysis by electronic tongue using carbon nanotube paste electrodes
Authors: Suh S H , Waritanant T , Wattanavichean N , Jityen A , Osotchan T
Published: February 2023

Electrolyte drink becomes very popular nowadays that drinking aid in rehydration which mostly contain water, sugar, and electrolytes (Na, K, Mg, Ca ions). In this work, several electrolyte drinks including M sport, M-plus, Sponsor, Sponsor citrus, Gatorade were analyzed by electronic tongue comparing to mineral and tap water. Non-specified electrode array used in electronic tongue was fabricated by mixing carbon nanotube with copper oxide or several types of metal-phthalocyanine (MPc) including MnPc, FePc, CoPc and ZnPc. The electronic tongue system was developed by using automatic electrochemical measurement setup with rotating eight beaker tray together with electrode holder slider in up and down position. This system was controlled by Arduino with developed python protocol. The cyclic voltammetry measurement indicated an ion current flow between electrodes with peaks in some cases. These cyclic graphs were converted to the specific line graphs for further analysis. Principle component analysis was used to classify the signal into several distingue groups. It was found that with the first two principal components, the mineral water and tap water can be totally separate from the other electrolyte drinks with total variation of about 77%.
Question-answer teaching method to develop student’s understanding of buoyant force
Authors: Chirayangyuenyong S , Emarat N , Arayathanitkul K
Published: February 2023

Many students do not understand that fluid pressure is the cause of the buoyant force. This work designed a process called question-answer teaching method to help improve this understanding. Sets of questions were developed which can be catagorized into three types: concept-guiding questions, comprehension-checking questions, and concept-applying questions. The major process of the method is that the instructor uses sets of the designed questions in class to encourage students and challenge their understanding. By expressing and discussing their ideas with peers and with the instructor, their misconceptions could be corrected, and the concepts could be understood by themselves. To prove if this teaching method is effective, a study was conducted with two groups of students: a control group (N = 88) and an experimental group (N = 12). A multiple-choice conceptual test was provided as pre-test and post-test. It was found that the results of the two groups are significantly different (p-value = 0.01). The normalized gain of the traditional group is 0.08 while that of the experimental group is much higher, at 0.63. Moreover, the students in the experimental group showed better understanding. They could conclude that the buoyant force results from the pressure difference in fluids.
Determination of phase change correction on gauge block measurement in two different interferometric measurement systems
Authors: Pringkasemchai A , Wongsaroj J , Mongkolsuttirat K
Published: February 2023

Phase change correction (PCC) is an important correction value of the end effect in an optical interferometry system. Normally, this value is used to compensate for gauge block measurement by an optical interferometry system based on ISO 3650:1998. Two different interferometric measurement systems in terms of fringe fraction measurement were performed to determine the phase change correction by a five-stacking method. These results are used to determine the length measurement of gauge blocks in an optical interferometer technique and consequently, to evaluate the uncertainty of gauge blocks measurement. The preliminary results for steel gauge block are shown that the value of phase change correction in a phase shift gauge block interferometer (PSGBI) system and a standard uncertainty are 35.2 nm and 5.8 nm, respectively. In contrast, the values from an average slits gauge block interferometer (ASGBI) system and a standard uncertainty are 66.0 nm and 6.0 nm, respectively. We found that the phase correction from the PSGBI system is lower than ASGBI about 0.53 - 0.56 times because the different of wave front correction in two interferometric systems. However, the lengths of gauge blocks of all materials measured by the two systems were consistent as assessed by En number. According to the study, we can conclude that phase change correction is based on the characteristics of each GBI system, surface texture characteristic in term of wringing condition and material types of gauge block and optical plates such as the fringe fraction measurement technique, and wave front error compensation. Consequently, measurements that require a high accuracy should determine the phase change correction before each measurement due to this value is not interchangeable.
A design of laser triangulation system with combined diffuse and specular reflection modes for dull and shiny surface measurements
Authors: Kerdkaew C , Kaewpho S , Srisakorn A , Chomkokard S , Yaemglin T , Cheowanish I , Jinuntuya N , Wongkokua W
Published: February 2023

Conventional laser triangulations are designed to measure the depth or height on a dull or rough surface. This can be done by projecting a light perpendicularly to the surface and capturing the spot of the diffuse reflection which is scattered from the surface. However, for a shiny or smooth surface, the specular reflection dominates, and it is difficult to detect diffuse reflection. We may modify the system setting to capture the specular reflection, with the cost of losing the diffuse reflection information. In this article, we proposed a design of dual diffuse and specular reflection mode of laser triangulation. The advantage is that there is no need to repeat alignment and calibration processes when we change the measuring mode, so we can easily select the measuring mode that is suitable for each surface. We have described the system setting and the calibration results where we can achieve the resolution of micrometre for both measuring modes.
The dynamics of pill millipedes’ flipping
Authors: Sirimachan P , Danphitsanuparn P , Sodadee R , Lakmuang T , Preechanukul N
Published: February 2023

This study aims to find an equation of motion that can describe the flipping motion of the pill millipede (Zephronia siamensis Hirst). From observation, the flipping motion can be characterized into four types. Moreover, the pill millipede’s shell curve that contacts the flat surface while flipping can be described as a form of the hyperbolic cosine function. Therefore, the equation of motion of flipping can be derived. From the geometry of the cross-section of the pill millipede, an angle between the vertical axis and the symmetry axis, a critical angle that allows it to flip, was obtained. Moreover, the maximum angle, the angle between its symmetry axis to the last point that hyperbolic cosine is fitted the shell’s curve, could be defined. We have found that the critical angle must be smaller than the maximum angle to provide a successful flipping with a minimal initial velocity. The equation of motion of flipping has been solved and tested by plotting the flipping angle as a function of time compared to the flipping angle from observation.
Modeling the navigation of a weaver ant in a simple, unfamiliar environment
Authors: Charoonratana L , Smith M F , Thiwatwaranikul T , Paisanpan P , Suksombat S
Published: February 2023

The ant species Oecophylla smaragdina, commonly known as the weaver ant, is native to tropical Asia and Africa. All ants are known for highly-organized, co-operative behavior and weaver ants are particularly adept at working together, in numbers, to accomplish large-scale tasks. Considered an example of a coherent many-body system, weaver ants have been studied by researchers in various fields. As a first step towards understanding weaver ant coordinated motion, we want to find the algorithm that a single ant employs for its own navigation. Having previously tracked the motion of individual ants within a small, bounded arena, we here present a simple theoretical model that can describe this motion. We show that their navigation can be adequately modeled as Brownian motion: the ant velocity changes by random impulses drawn independently from a robust probability distribution. Using established Brownian motion theory, we show that the ant’s tendency to remain near boundaries can be explained as a result of pure chance: having been stopped at the boundary, random motion is unlikely to bring the ant back to the arena interior. All qualitative aspects of ant motion are captured by a model with few parameters and without any assumptions about the ant’s intent. that an ant has preferences for position or velocity.
The smartphone and low-cost microcontroller as an AC circuit study kit for high school
Authors: Luangthongkham K , Krittinatham W , Unai S
Published: February 2023

This article presents a smartphone and a low-cost microcontroller-based AC circuit educational module focusing on the measurements of alternating voltage, frequency, and phase shift as well as learning about a phasor diagram. A smartphone provides a signal generator as a signal source, the ESP32 microcontroller works for signal acquisition and the beadboard RC series circuit is a test circuit. In-house developed software, based on Microsoft Visual Basic (VB), was used for monitoring the input signal like an oscilloscope. The measured frequency and phase shift agree with the results obtained from the commercial oscilloscope benchtop. This developed module is an apparatus that may be useful in online learning situations with the home experiment during the pandemic situation and used in high school that lacks the instruments, i.e., function generator and oscilloscope.
Investigation of plasma activated water in the growth of green microalgae (Chlorella spp.)
Authors: Silapasert P , Yatongchai C , Sarapirom S
Published: February 2023

The reactive oxygen nitrogen species (RONS) from plasma activation is intensively used in agriculture, particularly in the regulation of seeds germination and plants growth. It shows a promising effect on increasing the germination rate and promoting the growth of plants. This research employed plasma activated water (PAW) in cultivation of green algae (Chlorella spp.). The objective of this research was to introduce a comparison between the use of different fluids for cultivation of green microalgae. The experiment was carried out using cultivation of green microalgae in different fluids which were fertilized water, simulated-fertilized water, tap water, tap water treated with activated plasma for 2.5, 5.0 and 7.5 minutes. Samples of green microalgae were cultivated in these waters for 7 days. A comparative investigation was then conducted. It was found that nitrates remained constant at 10 mg/L on all treatment times, while the concentration of hydrogen peroxide considerably increased with the treatment time. According to the growth of green algae, a better result than simulated-fertilized water and tap water. This indicates an effect of RNS on promoting the growth of green algae. Upon completion of the test, the fertilized water showed the highest growth. However, a well-controlled plasma activation would make PAW possible for industrial uses in the future.
Influence of HCl-doping on physical, optical, and electrical properties of PEDOT:PSS films
Authors: Moungsrijun Sasimonton , Somsuk Suparat , Wongrerkdee Sawitree , Lohawet Khathawut , Sujinnapram Supphadate , Krobthong Sucheewan , Kaewprajak Anusit , Kumnorkaew Pisist , Wongrerkdee Sutthipoj
Published: February 2023

In this study, the preparation of HCl-doped PEDOT:PSS films was performed on fluorine-doped tin oxide substrates using spin coating method. The only SnO2 peaks were observed in the X-ray diffraction patterns. However, the functional groups that the FT-IR showed match with PEDOT and PSS. Contact angle measurement revealed that contact angle values increased for HCl-doped PEDOT:PSS films in comparison with undoped ones, which implies water tolerance improvement. In terms of optical transmittance, there were similar transmittance spectra for undoped and HCl-doped PEDOT:PSS films. Sheet resistance measurements exhibited that sheet resistance values decreased to the minimum values of 6.67 Ω/sq for HCl-doped PEDOT:PSS conditions. This indicates that the sheet resistance of PEDOT:PSS films can be reduced by HCl. Therefore, the HCl-doping could potentially be a suitable alternative for improving humidity tolerance and conductivity of PEDOT:PSS films.
Ab-initio study and atomistic spin model simulations of Cr2O3 thin films
Authors: Kunyangyuen Boonthum , Pinsook Udomsilp , Kittiwatanakul Salinporn
Published: February 2023

Magnetoelectric random access memory (MERAM) is the next generation technology of data storage with high-density and low power. Magnetoelectric material can be controlled by voltage such as an electric field to transform spin domain directions for storing data. One of the most promising materials that possess such properties near room temperature is Cr2O3. Although, the bulk has perfect properties for MERAM, it is necessary to fabricate thin films for applicable spintronic devices, i.e., reducing the required external control voltage; however, the film magnetic and physical properties might be different from bulk. In this work, we propose that the film properties might be induced by surface effects and are confirmed with Ab-initio calculation and atomistic spin simulation. The main simulation processes are the density functional theory (DFT) calculating, mapped with the classical Heisenberg model for exchange interaction constants up to the fifth nearest neighbour (J
1-J
5). The atomistic spin model was then used to approximate the Néel temperature (T
N), comparing two methods i.e., Monte Carlo simulation and the Landau–Lifshitz–Gilbert (LLG) equation. The Néel temperatures of the film were found to be slightly lower than the bulk, which is in good agreement with previous experiments. Furthermore, the spin dynamic model gives more correct result comparing to the Monte Carlo method.
External pressure effects on superfluid density of isotropic s-wave superconductors
Authors: Chanilkul G , Changjan A , Nilkamjon T , Udomsamuthirun P
Published: February 2023

Through using BCS theory and the semi-classical approach, the effect of external pressure on the superfluid density of s-wave isotropic superconductors were explored. The pressure parameters as the energy dispersion relation and the height of the density of state were applied. The analytical formula of superfluid density under pressure were derived and the numerical calculation results were compared to the experimental results of H3S and LaH10 superconductors. We discovered that the superfluid density under pressure of H3S and LaH10 superconductors fit our results closely. As the height of the density of state increased, so did the superfluid density.
Electronic and magnetic properties of MoTe2 monolayer doped with single and double transition metals: spin density functional theory
Authors: Thajitr Waritsara , Busayaporn Wutthikrai , Sukkabot Worasak
Published: February 2023

The spin density functional computations are exploited to determine the electronic and magnetic properties of MoTe2 monolayer doped with single and double transition metal atoms (V, Cr, Mn, Fe and Co). These properties are sensitive with the types and numbers of the doping transition metals. The semiconductors with narrow band gaps are shown in Cr and Co single-doped MoTe2 monolayer. V and Mn single-doped MoTe2 monolayer are metal. Fe single-doped MoTe2 monolayer reveals the half-metallic behaviours with a 100% spin polarization. V and Co provide the first-two lowest formation energies and are used for the co-doping studies. MoTe2 monolayers simultaneously doped with two Co are characterized as half metal, while the others are metal. The p-d and d-d hybridization around the Fermi level introduce the magnetism, called double exchange mechanism.
Physical properties and microstructure of traditional kaolin-based ceramics with additive fly–ash (FA)
Authors: Funsueb N , Thipboonraj A , Wannawek A , Pranamornkith P , Panthuwat W
Published: February 2023

In this research, the kaolin–based ceramic with 10-50 wt.% FA additive was fabricated by solid-state reaction. All powders were weighed, mixed and further milled by ball-milling for 4 h. All compositions of powders were uniaxial pressed in pellets and sintered at 1100 °C for 4 h. The XRD pattern of kaolin with FA additive showed that the kaolin phase was decreased with increasing FA and the single peak and the right shift resulted from the mix phase between quart phase and mullite phase of 40 to 50 wt.% FA. The SEM image of 10 to 30 wt.% FA addition illustrated melting grain and high roughness surface area. However, at the concentration of 40 to 50 wt.% FA addition provided the flat surface area and increased a porosity of the ceramics. The optimization of physical properties of ceramics included density, average linear shrinkage and hardness are 2.63 g/cm3, 24.62% and 135.32 kgf, respectively. The physical properties and microstructure of kaolin-based ceramics with FA additive are as the results of a structure properties relation.
The effect of natural fiber ratio on mechanical properties of kaolin/fly–ash at low temperature ceramics
Authors: Panthuwat W , Thipboonraj A , Wannawek A , Pranamornkith P , Funsueb N
Published: February 2023

This study aims to increase the feasibility of ceramics at low temperature using natural fibers. The ceramics (Ce) were prepared by mixing a powder of kaolin and fly–ash at an equal ratio of 50:50 wt.%. The mixture was milled by ball–milling technique. The natural fibers ceramics (CeNF) were created by adding local pineapple leaves to kaolin and fly–ash powder. Scanning electron microscopy (SEM) was used to amorphous observation and particle size determination. The compositions of Ce and CeNF were investigated by using X–ray diffraction (XRD) technique. The mechanical properties of ceramics were determined by hardness and density test. The results showed that the grinding of kaolin and fly–ash for 4 h produced the highest strength Ce. For the addition of local pineapple leaves at 2 wt.%, the strength could be increased from 92.9 kgf to 118.3 kgf.
Effect of self–assembled iron–tannic nanoparticles on the fastness and antibacterial properties of natural indigo dyed polyester cotton blended fabrics from Strobilanthes cusia (Nees) Kuntze
Authors: Keereeta Y , Srithong S , Pranamornkith P , Tharawatchruk W , Boonsom K , Klinbumrung A , Kaowphong S
Published: February 2023

In this study, self–assembled iron (III)–tannic nanoparticles (Fe–TA NPs) were synthesized at room temperature using a simple, low–cost, and reproducible method. The interaction between Fe3+ and TA, and the particle size of Fe–TA NPs with different mole ratios of ferric chloride and tannic acid were characterized by UV–vis spectroscopy and dynamic light scattering (DLS). The modified fabrics were fabricated by one–step depositing Fe–TA NPs onto the surface of natural indigo dyed polyester cotton blended fabrics using the exhaustion dyeing process. SEM, FTIR, Raman spectroscopy, and TGA were used to investigate the surface morphology, chemical structure, and thermal stability of the modified fabrics. According to the results, indigo–dyed fabrics treated with Fe–TA NPs showed an excellent antibacterial activity against both gram–negative (E. coli) and gram–positive (S. aureus) bacteria, improving of thermal stability, light fastness acceptance, washing fastness, and color fastness to heat.
Synthesis and application of nickel compound quantum dots by electrochemical process
Authors: Phimsarn Prapasiri , Panyathip Rangsan , Hongsith Kritsada , Sucharitakul Sukrit , Phadungdhitidhada Surachet , Choopun Supab
Published: February 2023

In this work, nickel compound quantum dots (Ni-QDs) are synthesized by the electrochemical process. The electrochemical process known as a facile method is used to prepare Ni-QDs colloid solution. Ni-QDs are synthesized using nickel-metal rods dipped into an electrolyte solution of potassium chloride and citric acid at 0.4M and 0.1M concentrations, respectively, then applied voltages at 1, 3, and 6 V at various synthesis times for the synthesis process. As a result, Ni-QDs are characterized for size by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The absorption spectra of Ni-QDs are indicated via ultraviolet-visible spectroscopy (UV-vis) at 390, 655, and 731 nm of wavelengths, which can be assigned to absorption peaks of Ni (OH)2 and NiCl2, respectively. The crystalline structure and photoluminescence properties of Ni-QDs are examined with selected area electron diffraction (SAED) and photoluminescence spectroscopy. It is found that the Ni-QDs growth rate can be controlled by the various voltages applied in the synthesis process. The smallest size of Ni-QDs is achieved with the low voltage applied (1V) at 6 hrs, while the higher voltage process produced a strong chemical reaction resulting in the lower yield of Ni-QDs due to the large particles of the obtained products. Thus, the Ni-QDs at 1V condition is considered the optimum condition, indicating the smallest hydrodynamic size (187±1.43 nm) and revealing the high stability of Ni-QDs dispersed in solution, as shown in the homogeneous solution compared to Ni- QDs in other conditions. Consequently, the influence of voltage and synthesis time in the synthesis of Ni-QDs is important to optimize the quality of Ni-QDs.
Enhancement of Perovskite solar cells performance using electrochemically grown TiO2 quantum dots
Authors: Sintiam Thanakrit , Saranrom Natpapon , Phadungdhitidhada Surachet , Choopun Supab , Sucharitakul Sukrit
Published: February 2023

Perovskite solar cells (PSCs) have been at the center of attention for research and development of clean energy technology. The platform promises high performance with relatively cheap and low-temperature processing. The main hindrance of the platform is low stability and performance degradation due to humidity. Most defects and degradation often stem from interfaces between the perovskite layer (PSVK) and carrier transporting layer. This work aimed to solve such an issue by improving the interface between the Perovskite layer (PSVK) and electron transporting layer (ETL) made of titanium in the Perovskite solution. That is methylammonium formamidinium lead iodide (FA0.3MA0.7PbI3) PSCs using electrochemical grown TiO2 quantum dots (QDs) mixed in Titanium tetraisopropoxide (TTIP). TiO2 QDs have grown electrochemically in potassium chloride (KCl) solution and then mixed in TTIP with various concentrations (0%, 2.5%, 5.0%, 7.5%, and 10%). The photoconversion efficiency (PCE) of PSCs was improved to 14.05 % while 7.5% of TiO2 QDs passivation with the champion performance of 15.72% (a significant improvement from the 0% standard condition). The PSCs also lasted over 200 hours, demonstrating increased stability with the proposed recipe. This work demonstrated the successful delivery of alkaline passivation using TiO2 QDs as an agent for improving PSCs.
Effect of annealing conditions on VO2 thin films prepared by sol-gel method
Authors: Panburana Pongsatorn , Chatraphorn Sojiphong , Kittiwatanakul Salinporn
Published: February 2023

Vanadium dioxide has attracted considerable attention because of the semiconductor-metal transition at 68 °C. This reversible transition changes crystal structure from monoclinic to rutile resulting in tremendously change of transmittance and reflectance of infrared wavelength and electrical resistance making VO2 thin film potential candidate for energy-saving smart windows—automatically block heat. However, the preparation is very challenging due to the multivalence of vanadium element. In this study, we explored different annealing conditions for thin films synthesized by sol-gel method which has advantage over other methods such as lower cost, simpler process, and ability to make large scale thin films. In the experiment, vanadium (V) triisopropoxy oxide (VO(OC3H7)3) was used as precursor. The annealing conditions explored are annealing temperature and annealing time of thin films in argon rich environment. The spin-coated films were annealed at 300-500 °C for 30 minutes, while another set was annealed at 450 °C for 30, 60, 90, and 120 minutes, respectively. Then the films were characterized with Raman spectroscopy and temperature dependent resistance measurement. The results show that the longer the annealing time and the higher the annealing temperature are better for film formation—closer to VO2 (higher V:O ratio). In addition, the effect of various substrate types was also explored, another set of thin films was coated on c-plane sapphire (c-Al2O3) and soda lime glass (mostly SiO2) to compare the effect. Then the films were characterized with Raman spectroscopy and X-Ray Diffraction (XRD). The result showed that sapphire substrate yielded better film formation.
Gamma irradiation assisted nickel impregnation on activated carbon derived from water hyacinth for electrocatalyst application
Authors: Tonkaew Piyapat , Deechakawan Nicharee , Kanjanakosit Nichawadee , Chanta-urai Treepat , Kwamman Tanagorn , Chutimasakul Threeraphat , Anantachaisilp Suranan
Published: February 2023

Water hyacinth (WH) is an invasive floating plant causing water pollution. However, its leaves contain a high cellulose content, which can be used as biomass to synthesize activated carbon. Thus, in this study, water hyacinth was subjected to the KOH activation process to obtain water hyacinth-based activated carbon (WH/AC). Moreover, as a novel method for nickel impregnation, gamma irradiation was proposed as an alternative to replacing the traditional method due to its high penetration power and energy. To obtain the optimal condition for nickel impregnation, different absorbed doses of gamma-ray (0, 20, 100 kGy) were applied to commercial activated carbon (AC), represented as 0-AC, 20-AC, and 100-AC, respectively. These samples were thoroughly characterized with BET, SEM-EDS, XRD, FTIR, and XPS. The BET surface area of commercial activated carbon increases as the absorbed dose of gamma-ray increases. The SEM images revealed that the surface morphology of the commercial activated carbon significantly changed, becoming more spherical in structure, and distributed after gamma irradiation. As a result, the optimal absorbed dose for nickel impregnation is 20 kGy. Thus, the 20 kGy absorbed dose of gamma-ray was carried out in WH/AC, yielding 20-WH/AC. From the XPS results, 20-WH/AC has a more incredible amount of nickel deposited on the surface. The activated carbon electrocatalysts were investigated for applying electrochemical carbon dioxide reduction reaction (CO2RR) by linear sweep voltammetry (LSV). Interestingly, 20-WH/AC electrocatalyst exhibited the highest CO2RR efficiency compared to others. All results indicate that water hyacinth can potentially be utilized as a raw material in producing nickel-impregnated activated carbon irradiated with gamma rays.