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Enhanced photocatalytic ability of CuO/Ni-doped TiO2 nanocomposite under visible light: Theory and experiment
(2025-09-01)
Bootchanont, Atipong
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Samerchue, Sorravich
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Sipae, Chanapong
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Zhao, Huali
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Noonuruk, Russameeruk
CuO/Ni-doped TiO<inf>2</inf> composite photocatalysts were synthesized using a co-precipitation method as the composite of Ni-doped TiO<inf>2</inf> (Ni–TiO<inf>2</inf>) with 0.5, 1.0, and 1.5 mol% of CuO. Composites with different CuO/Ni–TiO<inf>2</inf> ratios were studied to assess the influence of Ni and CuO on the crystal and local structure by X-ray diffraction (XRD) and X-ray absorption (XAS). The energy bandgap is investigated by UV–visible spectroscopy and is described by computational calculations using density functional theory (DFT). The correlation between the local site of Ni and the band structure will be analyzed and discussed by comparing the experiment and First-principle calculations. The photocatalytic activity of the CuO/Ni–TiO<inf>2</inf> systems is due to the absorption of radiation in the visible light region. The results indicated that 1.5 mol% of CuO contributes to the Ni–TiO<inf>2</inf> nanoparticles showing highest photocatalytic activity with rate constant of 0.03477 min<sup>−1</sup> in the degradation of Rhodamine B, which could be attributed to the low recombination rate of the electron-hole pair, and decrease of the bandgap, increase in the concentration of •OH radicals in the solution, which is beneficial for improving the photo degradation rate of organic compounds.
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Pressure and atomic size effects of IV cation on mechanical and electronic properties of Zn-IV-N2 (IV[dbnd]Si, Ge and Sn): First principles calculation
(2024-09-01)
Boonkhuang, Apiwat
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Kongnok, Thanundon
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Meethan, Weerachon
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Busayaporn, Wutthikrai
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Phacheerak, Kanoknan
Zn-IV-N<inf>2</inf> compounds, incorporating Si, Ge, and Sn, have emerged as pivotal materials for their mechanical and electronic properties, influencing optoelectronic devices and photovoltaic applications. Employing density functional theory (DFT), we comprehensively investigate the structural, elastic, mechanical, and electronic characteristics of ZnIVN<inf>2</inf> (IV[dbnd]Si, Ge, Sn) under ambient and pressure conditions up to 20 GPa. Our findings suggest that a larger atomic size of the group IV cation can be more easily compressed than a smaller size. The mechanical stability criteria and the phonon dispersion show mechanical and dynamic stability in both ambient pressure and under high pressure up to 20 GPa. The ZnSiN<inf>2</inf> and ZnGeN<inf>2</inf> exhibit linear increments in bulk modulus (B), shear modulus (G), and Young's modulus (E) under pressure, while ZnSnN<inf>2</inf> experiences a decrease in G and E. Notably, the energy gap of ZnSiN<inf>2</inf>, ZnGeN<inf>2</inf>, and ZnSnN<inf>2</inf> (4.62 eV indirect, 2.82 eV, 1.16 eV, respectively) increases with pressure due to higher N s orbital energy, approaching the UV region. In the valence band, a hybridization of N p and Si/Ge/Sn p orbitals is observed, offering opportunities to tailor the band gap for optimal applications in optoelectronic devices. Preferentially adjusting group-IV elements over group-II elements is recommended for optimizing band gap modulation. The correlation between larger atomic size and decreased band gap energy highlights the potential to fine-tune material properties through controlled variations in group-IV elements.
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Influence of pressure on elasticity, mechanical properties, and Li diffusion in battery electrode material LiCoO2: First-principles calculations
(2023-09-01)
Sailuam, Wutthigrai
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Fongkaew, Ittipon
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Busayaporn, Wutthikrai
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Klinkla, Rakchat
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Phacheerak, Kanoknan
This study used first-principles calculations based on density functional theory with generalized gradient approximation (GGA) of the Perdew Burke and Ernzerhof (PBE) parameterized form to investigate the influence of pressure on the structural, elastic, and mechanical properties of rhombohedral LiCoO<inf>2</inf>. The results indicate that rhombohedral LiCoO<inf>2</inf> remains stable up to 10 GPa. The calculated ground state properties agree well with experimental and other calculation data, validating the approach. Additionally, the calculated elastic constants, bulk modulus, Young's modulus, shear modulus, and Poisson's ratio at 0 GPa agree with previous results. The study found that all elastic constants continuously increase with increasing pressure. The deformation resistances along the axial direction are stronger than those in shape. The relationship between elasticity and length is such that C<inf>11</inf> > C<inf>33</inf>, indicating that the incompressibility along the a axis is stronger than that along the c axis. The analysis of Poisson's ratio (ν) and Pugh's criterion B/G strongly suggests that rhombohedral LiCoO<inf>2</inf> exhibits ductile behavior under pressure up to 10 GPa. The material is clearly anisotropic behavior, but the material exhibits improved isotropic behavior as pressure increases. Regarding Li ion diffusion in rhombohedral LiCoO<inf>2</inf>, the study found that the migration pathway for Li ions in rhombohedral LiCoO<inf>2</inf> is a direct route that extends from the V<inf>Li</inf> site to the closest Li site. The diffusion process is hindered by a diffusion energy barrier of 0.87 eV, which is in good agreement with available theoretical data. Furthermore, the Li ion diffusion energy barrier increases with pressure because the decrease in d<inf>mean</inf> and polyhedral volume, along with changes in angle and torsional distortion factors of CoO<inf>6</inf> octahedra, which can reduce the charging and discharging speeds of Li-ion batteries that use rhombohedral LiCoO<inf>2</inf> as the cathode material.
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Derosion Lattice Performance and Optimization in Solving an End Effect Assessed by CFD: A Case Study in Thailand’s Beach
(2022-05-01)
Thongsri, Jatuporn
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Tangsopa, Worapol
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Kaewbumrung, Mongkol
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Phanak, Mongkol
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Busayaporn, Wutthikrai
Thailand’s beach had a severe coastal erosion problem at the end of rock dams called the “end effect”. One of the innovative solutions to solve this problem is to use the derosion lattice (DL). However, since the DL performance depends on installing conditions such as angle of attack, placement position, terrain, and climate, computational fluid dynamics (CFD) was applied to assess the end effect’s occurrence and optimize the performance of DL’s installation. Based on Khao Rup Chang’s condition, a suffered beach in Thailand was used as a case study, and a free surface flow simulation was performed in the transient state using ANSYS Fluent, a CFD software, which revealed water waves flow through the beach with and without the DL installation cases. Furthermore, the CFD-assessed results indicated that the angle of attack and placement position affected the DL performance as expected. In optimization, the 15<sup>◦</sup> angle of attack with the DL placement adjacent to the rock dam was the proper condition. After being applied at the actual site, the DL can help reduce erosion, increase sedimentation, and solve the end effect with excellent performance.
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Nature of electronic topological transition and superconductivity in bismuth under high pressure from ab initio random structure searching
(2021-12-01)
Chaimayo, Wanaruk
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Tsuppayakorn-aek, Prutthipong
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Pluengphon, Prayoonsak
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Kotmool, Komsilp
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Pakornchote, Teerachote
We have predicted the hexagonal close-packed (hcp) structure of bismuth (Bi) using ab initio random structure searching (AIRSS) at extreme conditions. The calculation, which included spin–orbit coupling, shows that the hcp structure is thermodynamically and dynamically stable at high pressure. The electronic band structure calculations suggest the downshifting of the flat band through compression due to Lifshitz transitions. The Fermi surface shape of hcp Bi produces the metallicity in this material. The electron localization function reveals a weak bonding of Bi. The solutions of electronic topological transition and a soft-mode of phonon dispersion provide the possibility for prediction and reduction of the superconducting transition temperature.
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A proper shape of the trailing edge modification to solve a housing damage problem in a gas turbine power plant
(2021-04-01)
Jansaengsuk, Thodsaphon
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Kaewbumrung, Mongkol
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Busayaporn, Wutthikrai
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Thongsri, Jatuporn
To solve the housing damage problem of a fractured compressor blade (CB) caused by an impact on the inner casing of a gas turbine in the seventh stage (from 15 stages), modifications of the trailing edge (TE) of the CB have been proposed, namely 6.5 mm curved cutting and a combination of 4 mm straight cutting with 6.5 mm curved cutting. The simulation results of the modifications in both aerodynamics variables C<inf>l</inf> and C<inf>d</inf> and the pressure ratio, including structural dynamics such as a normalized power spectrum, frequency, total deformation, equivalent stress, and the safety factor, found that 6.5 mm curved cutting could deliver the aerodynamics and structural dynamics similar to the original CB. This result also overcomes the previous work that proposed 5.0 mm straight cutting. This work also indicates that the operation of a CB gives uneven pressure and temperature, which get higher in the TE area. The slightly modified CB can present the difference in the properties of both the aerodynamics and the structural dynamics. Therefore, any modifications of the TE should be investigated for both properties simultaneously. Finally, the results from this work can be very useful information for the modification of the CB in the housing damage problem of the other rotating types of machinery in a gas turbine power plant.
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Vibration Analysis and Development of a Submersible Ultrasonic Transducer for an Application in the Inhibitory Activity of Pathogenic Bacteria
(2021-01-01)
Srathonghuam, Kamonwan
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Wonganu, Benjamaporn
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Busayaporn, Wutthikrai
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Thongsri, Jatuporn
Development of a new generation of a submersible ultrasonic transducer (SUT) using vibrational analysis aimed for higher efficiency and inhibitory activity of pathogenic bacteria has been presented. The SUT with a dual-stepped shape of front mass and PZT8 transducer working at 50W, 110V, 50 kHz has been examined by the plate counting method. It was found that the SUT could inhibit pathogenic bacteria, e.g., Escherichia coli, Salmonella typhi, Staphylococcus epidermidis, and Staphylococcus aureus. For the vibrational analysis, the results were derived from structural and acoustic simulations using harmonic response analysis (HRA) in ANSYS software. In the structural simulation, the results showed a natural frequency and total deformations both inside and outside of the original SUT corresponding to the results measured by a laser doppler vibrometer. The acoustic simulation, set up as an actual operation at different depths from the water surface, has been applied. The HRA revealed various distributions of acoustic pressure. For further distances away from the SUT, the acoustic pressure decreased. When the SUT has been submerged deeper into the media, the acoustic pressure becomes larger at positions close to the bottom of the tank. This discovery is consistent with power concentration measurement. For the development of the SUT, this research proposed other 5 models as the candidate to be investigated. The results from the acoustic simulation confirmed that the different shapes of the front mass provided different acoustic pressure distributions. The wider head of the front mass in the modified dual-stepped shape generated the highest acoustic pressure and was fully distributed through an all-over cleaning tank. Therefore, this proposed model is suitable for industrial commercialization and possesses the inhibitory activity of pathogenic bacteria.
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Evaluation and improvement of ventilation systemreduceinside low-costparticle contaminationautomation line to
(2020-02-28)
Puangburee, Lamai
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Busayaporn, Wutthikrai
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Kaewbumrung, Mongkol
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Thongsri, Jatuporn
A Low-Cost Automation (LCA) line, a group of machines to manufacture hard disk drive’s components located inside a clean room of factory, faces the problem of particle contamination caused by an improper ventilation system. To solve this problem, Computational Fluid Dynamics (CFD) has been implemented to evaluate airflow and simulate solutions to improve the ventilation system of the LCA. By using actual operating conditions collected at the factory and Fluent CFD software, the simulation showed that airflow patterns in such areas were substandard. For example, the large areas of recirculation zone with air velocities lower than 0.2 m/s such as Fan Filter Units’ conveyor and Work Area. The low ve-locity of the airflow can cause particle contamination and leads to low-quality production. To reduce the particle contamination, we suggested novel solutions based on the CFD results by increasing the momen-tum source (S<inf>m</inf>) and/or redesigning the LCA’s model especially extending its height of cover. The increasing of S<inf>m</inf> can be simply implemented by increasing the air-condition power to the optimal values accord-ing to the calculation leading to a reduction in recir-culation areas. In addition, extending the height of the LCA’s cover also improved the air velocities in the critical areas to meet the factory’s standard.
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First-principles investigations of structural and elastic properties of LiGaO2 under pressure
(2019-09-01)
Sailuam, Wutthigrai
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Busayaporn, Wutthikrai
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Limpijumnong, Sukit
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Phacheerak, Kanoknan
The structural and elastic properties of the LiGaO<inf>2</inf> with an orthorhombic-type structure (Pna2<inf>1</inf>-LGO) under pressure were investigated using first-principles calculations. The calculated structural parameters and elastic constants show a good agreement with the experimental and other theoretical values. The structural parameters and elastic constants of Pna2<inf>1</inf>-LGO under various pressures are calculated. All structural parameters are found to be decreased with pressure. The elastic constants are found to increase with pressure, except for C<inf>44</inf> and C<inf>55</inf>. It was also found that the elastic constants C<inf>11</inf>, C<inf>22</inf>, and C<inf>33</inf> which represent the elasticity in length are always larger than the elastic constants C<inf>12</inf>, C<inf>13</inf>, C<inf>23</inf>, C<inf>44</inf>, C<inf>55</inf>, and C<inf>66</inf> which represent the elasticity in shape at the same pressure. The details of pressure dependences of the structural and elastic constants are also presented and discussed.
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Simulation of ultrasonic cleaning and ways to improve the efficiency
(2017-10-19)
Tangsopha, Worapol
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Thongsri, Jatuporn
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Busayaporn, Wutthikrai
Based on practical problem in industrial ultrasonic cleaning, this research has an objective to simulate acoustic pressure leading to cavitation in a cleaning tank. By using Harmonic response in ANSYS as simulation software, acoustic pressure distribution has been simulated at different position in the cleaning tank. The result has been confirmed by aluminum foil corrosion test. The simulations show that increasing power of piezoelectric transducers can lead to increasing the power of acoustic pressure; however, it cannot lead to the change of acoustic pressure distribution. To change the acoustic pressure distribution, the difference of frequencies is required. For such typical ultrasonic cleaning tank, the position of the highest cleaning efficiency is at the middle of the tank. Finally, the result can lead to the optimization between the power and frequency of ultrasonic to reach the maximum cleaning efficiency.

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