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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
;
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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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
;
Phunpueok, Akapong
;
Jaiyen, Sarawut
;
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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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
;
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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