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Characterization of dust particles generated in Thailand Tokamak-1
(2027-01-01)
Nilgumhang, Kewalee
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Chokchaiworadilok, Sirat
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Poolyarat, Nopporn
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Dangtip, Somsak
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Limsuwan, Pichet
Thailand Tokamak-1 (TT-1) is the first magnetic confinement fusion device in Thailand and the ASEAN region. During plasma operation, plasma–wall interactions (PWI) inevitably lead to erosion of the 316L stainless-steel vacuum vessel and the boronized first wall, resulting in dust generation and plasma contamination. This work investigates the morphology and elemental composition of dust particles collected from the TT-1 vacuum chamber after plasma campaigns. In this experiment, we carried out a total of 604 discharge operation shots over a period of three months, using 99.999% purity H<inf>2</inf> gas as the fuel gas and 99.999% purity He gas for Glow Discharge Cleaning (GDC). Dust was sampled from the inner surface of the vacuum vessel using carbon tape and analyzed by field-emission scanning electron microscopy (FE-SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Four primary dust morphologies were identified: (i) smooth flake-like particles, (ii) grain-crack particles with surface cracking, (iii) granular particles with fine grains distributed across the surface, and (iv) cauliflower-like structures attributed to repeated thermal cycling. EDS analysis revealed that Fe, Cr, and Ni, originating from the 316L stainless-steel wall, are the dominant metallic constituents, together with light elements such as B, C, and O associated with the boronization layer and subsequent oxidation. The presence of B- and C-rich granular dust confirms successful deposition and erosion of the boron coating used for wall conditioning. These results demonstrate that dust generated in TT-1 is a mixture of wall and boronization-layer fragments, which poses potential theoretical risks of plasma impurity accumulation, enhanced radiative losses, and compromised plasma ignition and stability in future high-performance campaigns. The present characterization provides a basis for future studies on dust transport, retention, and mitigation strategies in TT-1 and similar medium-size tokamak devices.
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Synergistic effects of biomass-derived carbon quantum dots and Cu Co-doping on TiO2 nanocomposite for enhanced visible-light photocatalysis
(2026-12-01)
Zhao, Huali
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Noonuruk, Russameeruk
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Bootchanont, Atipong
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Porjai, Porramain
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Thongpool, Voranuch
The development of sustainable approaches for enhancing the visible-light activity of TiO<inf>2</inf>-based photocatalysts has attracted considerable research interest. In this work, carbon quantum dots (CQDs)-Cu co-modified TiO<inf>2</inf> nanocomposites were synthesized via a hydrothermal method using butterfly pea ( Clitoria ternatea ) flowers as a biomass-derived carbon source. The Cu content was fixed at 1.5 mol% relative to Ti, while the CQDs loading was controlled by varying the butterfly pea precursor concentration from 0.25 to 1.25 g L−1, yielding 1C–Cu–TiO<inf>2</inf>, 3C–Cu–TiO<inf>2</inf>, and 5C–Cu–TiO<inf>2</inf> samples. The prepared materials were characterized by electron microscopy, X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy, photoluminescence (PL), and X-ray absorption spectroscopy (XAS). High-resolution transmission electron microscopy revealed CQDs with an average size of approximately 4.29 nm and an interplanar spacing of approximately 0.23 nm. All composites retained the anatase TiO<inf>2</inf> phase after Cu incorporation and CQDs modification. Enhanced visible-light absorption was observed and is attributed to the formation of Cu-related sub-band-gap states and the sensitization effect of CQDs. PL analysis showed an emission peak at ∼415 nm under 660 nm excitation, suggesting the presence of upconversion photoluminescence behavior in the CQDs. Conventional PL spectra further suggested reduced charge-carrier recombination in the modified composites. Photocatalytic activity was evaluated through Rhodamine B (RhB) degradation under visible-light irradiation. Among all samples, 1C–Cu–TiO<inf>2</inf> exhibited the highest performance, achieving degradation efficiency of 99.28% within 50 min. The apparent reaction rate constant reached 0.1038 min−1, which was 2.23, 1.96, and 2.90 times higher than those of pristine TiO<inf>2</inf>, Cu–TiO<inf>2</inf>, and 3C–Cu–TiO<inf>2</inf>, respectively. Radical scavenging experiments indicated that •OH and h+ were the dominant reactive species, while •O<inf>2</inf>− also participated in the degradation process. The enhanced photocatalytic performance is attributed to the synergistic effects of Cu and biomass-derived CQDs in improving visible-light harvesting and charge separation, providing an effective approach for developing visible-light-responsive TiO<inf>2</inf> photocatalysts.
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OSL chronology of stratified iron-smelting slag from the Don up Mung site, northeastern Thailand
(2026-11-01)
Phetkongtong, Thananan
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Nilgumhang, Kewalee
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Wongadsapaiboon, Thippawan
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Pailoplee, Santi
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Limsuwan, Pichet
Iron-smelting slag from the Don Up Mung archaeological site, Nong Bua Lamphu Province, northeastern Thailand, was investigated to evaluate the applicability of Optically Stimulated Luminescence (OSL) dating for archaeometallurgical materials. Slag samples recovered from stratified deposits between the surface and 100–110 cm depth were dated using the quartz inclusion method with the Single Aliquot Regeneration (SAR) protocol. Environmental dose rates were quantified by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) through in situ determination of uranium (U), thorium (Th), and potassium (K) concentrations, minimizing spatial heterogeneity effects commonly associated with bulk measurements. The obtained OSL ages range from 1426 ± 162 year to 2539 ± 223 year, indicating consistent burial histories across stratigraphic levels. Independent Accelerator Mass Spectrometry (AMS) radiocarbon ages of charcoal and human bone (1700–2600 year) show good agreement with the OSL results, supporting the reliability of the luminescence-derived chronology. These results demonstrate that OSL dating of iron-smelting slag, when combined with high-resolution dose rate assessment, provides robust chronological constraints and represents a valuable radiation-based approach for reconstructing metallurgical activity sequences in Southeast Asia.
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Plant assisted synthesis of CuO/ZnO heterojunction nanocomposites using Mitragyna speciosa (Korth.) Havil leaf extract for photocatalytic activity under full spectrum LED light and antibacterial performance
(2026-07-15)
Phunpueok, Akapong
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Thongpool, Voranuch
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Jaiyen, Sarawut
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Bootchanont, Atipong
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Sukprasit, Nuchita
CuO/ZnO heterojunction nanocomposites were synthesized through a green plant assisted method using Mitragyna speciosa leaf extract as a natural reducing and stabilizing agent. Structural and morphological analyses (XRD, FE-SEM, EDS, UV–vis, and BET) confirmed the formation of CuO/ZnO heterostructures with mesoporous characteristics. The 0.25CuO/0.75ZnO heterojunction nanocomposites exhibited the smallest ZnO crystallite size (∼8.06 nm) and the highest surface area (28.97 m2/g). Photocatalytic performance evaluated by methylene blue degradation under full-spectrum irradiation showed that the 0.25CuO/0.75ZnO heterojunction nanocomposites achieved 92.29% degradation within 90 min with a rate constant of 0.02491 min−1. In addition, the nanocomposites demonstrated strong antibacterial activity, achieving 99.9% reduction of E. coli and >99.9% inhibition of S. aureus . The enhanced performance is attributed to efficient charge separation at the CuO/ZnO heterojunction and the generation of reactive oxygen species.
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Williamson-Hall analysis of lattice strain in green-synthesized ZnO nanoparticles using Mitragyna speciosa extract: microstructural insights and antibacterial application
(2026-07-01)
Thongpool, Voranuch
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Phunpueok, Akapong
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Jaiyen, Sarawut
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Limsuwan, Pichet
Green synthesis is a sustainable method for producing ZnO NPs. However, detailed microstructural interpretation remains limited. In this study, ZnO NPs were synthesized using Mitragyna speciosa leaf extract and systematically analyzed with emphasis on lattice characteristics. Structural and morphological analysis using UV–vis, FTIR, FESEM-EDS, and XRD techniques confirmed the formation of highly crystalline ZnO with a hexagonal wurtzite structure. Williamson-Hall (W-H) analysis was applied using three deformation models: UDM, USDM, and UDEDM to separate crystallite size and lattice strain components of the crystal structure. The results revealed relatively large crystallite sizes (∼39–43 nm) with low microstrain (2.09–2.30 × 10⁻3) and low deformation energy density (3.1 × 10⁻4 J m⁻3), suggesting comparatively low lattice strain characteristics. The optical band gap obtained from the Tauc plot analysis is approximately 3.03 eV, consistent with the properties of the ZnO semiconductor. Antibacterial activity was evaluated as a preliminary functional assessment, showing typical Gram-dependent behavior. This work highlights the applicability of W–H analysis for detailed microstructural evaluation in green-synthesized ZnO NPs.
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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−1 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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Optically stimulated luminescence dating using the quartz inclusion method of earthenware from the Nam Tok Khao Pang archaeological site, Kanchanaburi, Thailand
(2025-08-28)
Phetkongtong, Thananan
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Klubket, Peerasak
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Pailoplee, Santi
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Limsuwan, Pichet
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Phunpueok, Akapong
The Nam Tok Khao Pang archaeological site, located in Tha Sao subdistrict, Sai Yok district, Kanchanaburi province, Thailand, is a limestone cave where numerous artifacts, including black-burnished earthenware fragments with in-curving rims, out-curving rims, and carinated bodies, have been discovered. Mineralogical and microstructural analyses using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) identified quartz (SiO₂) as the dominant mineral phase within a partially sintered silicate matrix. The absence of vitrification and the presence of mineral impurities indicate that the earthenware was fired at temperatures between 900°C and 1000°C. To determine the age of these ceramics, optically stimulated luminescence (OSL) dating was conducted on three black-burnished earthenware fragments using the quartz inclusion method and the single aliquot regeneration (SAR) protocol. Annual dose rates were estimated from uranium (U), thorium (Th), and potassium (K) concentrations measured by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS). The individual OSL ages obtained were 3.591 ± 0.63 ka, 3.479 ± 0.74 ka, and 3.717 ± 0.73 ka, yielding an average age of approximately 3.59 ± 0.34 ka. This places the artifacts within the Late Neolithic to Middle–Late Bronze Age period. These findings are consistent with the typological characteristics of the earthenware and align with radiocarbon dates obtained from charcoal collected from black-burnished earthenware vessels at the Ban Kao site, which also fall within the Late Neolithic period. This correlation supports the chronological framework of prehistoric settlement in the region and highlights the reliability of OSL dating for ceramic artifacts in tropical archaeological contexts.
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LUMINESCENCE DATING OF BRICK FROM NAKHON KALONG CITY ARCHAEOLOGICAL SITE IN NORTHEASTERN THAILAND
(2025-01-01)
Phetkongtong, Thananan
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Limsuwan, Pichet
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Pailoplee, Santi
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Thongpool, Voranuch
Nakhon Kalong, located in Ban Khon Sawan, Khon Sawan District, Chaiyaphum Province, Northeastern Thailand, is an archaeological site associated with the Dvaravati period (12th-16th Buddhist centuries). The site features distinctive characteristics of Dvaravati culture, including a moated settlement, earthen ramparts, laterite structures, sandstone sema markers (bai sema), and a large sandstone Buddha image. The bricks used in construction at the site were subjected to a heating process prior to use, which makes them suitable for luminescence dating. In this study, brick samples obtained as rubble from excavation sites in Ban Khon Sawan were analyzed to determine their age. The accumulated dose was measured using Optically Stimulated Luminescence (OSL) dating, while the annual dose was determined by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The annual dose was measured at 2.80±0.67 mGy per year, and the accumulated dose was found to be 2.92±0.24 Gy. These values yield an estimated luminescence age of 1,042±263 years. The dating results are consistent with historical records, confirming the occupation of Nakhon Kalong during the Dvaravati period.

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