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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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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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Microwave-activated reduced graphene oxide composite with hydrothermally treated corn husk activated carbon as an active electrode for high electrochemical performance in symmetrical carbon-based supercapacitor devices
(2026-07-01)
Srakaew, Khattiya
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Ratchayotee, Pornthip
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Janorat, Phattharawadee
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Phrompet, Chaiwat
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Kitiwan, Mettaya
This work applies microwaves for synthesizing reduced graphene oxide (rGO) and waste material corn husk activated carbon composites as active electrode materials for symmetric supercapacitors. The rGO is activated by microwave treatment and corn husk carbon by KOH in processed hydrothermal activation, followed by compositing at various weight ratios. Among all compositions, rGO:H_Corn_C (90:10) is reported with the best properties, with a specific surface area of 314.2 m2/g and a high specific capacitance of 1152 F/g at 0.1 A/g. The optimized composite also delivered increasing energy and power densities of up to 160 Wh/kg and 9.68 × 102 W/kg, respectively, within a 1 V operating window. In an experiment by assembling a symmetric coil cell supercapacitor, the device showed a specific capacitance of 142.23 F/g at 0.1 A/g, cycling stability with 98.8% capacitance retention after 1000 cycles of charge-discharge, and peak energy and power densities of 40.68 Wh/kg and 5.74 × 102 W/kg. Overall, the composite material with a high content of rGO and corn husk-derived activated carbon prepared by the hydrothermal method exhibits high-performance for the material in supercapacitor applications.
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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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Post-annealing effects on (00l) texture, Cl/Se ratio, and electrical and glass-like thermal transport in Bi₄O₄SeCl₂
(2026-04-25)
Somdock, Nuttakrit
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Theekhasuk, Nattharika
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Voraud, Athorn
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Limsuwan, Pichet
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Naemchanthara, Kittisakchai
Bi₄O₄SeCl₂ is a heteroanionic layered material with intrinsically low lattice thermal conductivity and anisotropic charge transport. In this work, the effects of post-annealing temperature on the crystallographic texture, anion chemistry, defect evolution, and transport properties of Bi₄O₄SeCl₂ were systematically investigated. Polycrystalline Bi₄O₄SeCl₂, synthesized by solid-state reaction combined with high-energy ball milling, was post-annealed at 400–700 °C. X-ray diffraction and electron microscopy revealed that post-annealing eliminated the residual BiOCl precursor phase, enhanced the (00 l) preferred orientation, and promoted grain growth up to 600 °C, followed by partial texture degradation at 700 °C due to recrystallization. Energy-dispersive spectroscopy showed progressive Se and Cl volatilization during annealing, leading to an increased Cl/Se ratio. The carrier mobility and electrical conductivity reached maximum values at 600 °C, consistent with improved texture and layered-domain connectivity. Thermal transport remained lattice-dominated and only weakly temperature-dependent. The phonon mean free path, estimated using kinetic theory, was in the sub-nanometer range (∼0.25–0.57 nm), comparable to the interatomic spacing, indicating glass-like phonon transport. Representative HRTEM observations also revealed dislocation-related lattice defects and locally distorted regions, suggesting that vacancy disorder and local strain fields may provide additional phonon scattering. These results demonstrate that post-annealing optimizes electrical transport through phase purification, texture development, and defect-mediated carrier regulation, while the lattice thermal conductivity remains fundamentally limited by intrinsic glass-like phonon transport in Bi₄O₄SeCl₂.
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Enhanced antimony telluride thermoelectric generators: From material synthesis to device applications
(2025-12-01)
Theekhasuk, Nattharika
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Sakdanuphab, Rachsak
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Voraud, Athorn
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Limsuwan, Pichet
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Sakulkalavek, Aparporn
This study investigates the effect of Bi₄O₄SeCl₂ (BOSC) addition (0–4 wt%) on the thermoelectric performance of p-type Bi₀.₅Sb₁.₅Te₃ synthesized via high-energy ball milling. XRD analysis revealed lattice incorporation at 1 wt% BOSC, while higher concentrations led to phase separation. The 1 wt% BOSC sample exhibited a significantly reduced total thermal conductivity of 0.28 W/m·K, compared to 0.46 W/m·K in the undoped sample, attributed to enhanced phonon scattering. Despite moderate decreases in electrical conductivity and Seebeck coefficient, a peak ZT of 1.02 at 50 °C was achieved—representing a ∼54 % improvement over the undoped material. Furthermore, a prototype thermoelectric module fabricated with BOSC-doped legs produced a power density of 17.6 mW/cm² under a 150 °C temperature gradient. These results demonstrate that BOSC is an effective additive for reducing thermal conductivity and enhancing overall thermoelectric performance, offering potential for energy harvesting applications at moderate temperatures.
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Growth stage detection for food consumption management in smart cricket farming using a deep learning technique
(2025-11-01)
Nutnoi, Nitipoom
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Yindeesuk, Witoon
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Kamoldilok, Surachart
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Srinuanjan, Keerayoot
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Limsuwan, Pichet
This research proposed a novel method for tracking and predicting the growth stages of two-spotted crickets, reared in a temperature-controlled box at different growth stages using the YOLOv5s model. The images of crickets feeding inside the rearing box were taken with an infrared camera above the feeding point every hour. Images of the cricket were used to train a YOLOv5s model to detect crickets for each growth stage in the rearing box. The experimental results showed that the trained deep learning had an average accuracy of 95.7%. The relationship between the ratio of crickets at each growth stage throughout the 45-day rearing period was plotted and discussed. The results also showed a clear relationship between the amount of food consumed by crickets per day and their growth stage, which could be useful for appropriately managing food consumption according to the growth stage of crickets.
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Flexible thermoelectric generator with radiative cooling for body-heat-driven self-powered Bluetooth low energy sensing system
(2025-10-01)
Gobpant, Jakrit
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Van Toan, Nguyen
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Ono, Takahito
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Tuoi, Truong Thi Kim
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Tran, Ngoc Dang Khoa
Wearable electronics and wireless IoT sensors are increasingly expected to operate in a self-powered manner. However, their practical deployment remains limited due to the lack of compact, flexible, and sustainable energy sources. Thermoelectric generators (TEGs), which convert body heat into electricity, present a promising solution but are typically hindered by small temperature gradients and the requirement of bulky heat sinks that compromise flexibility. To address these challenges, we developed an ultra-thin flexible thermoelectric generator (FTEG) integrated with a radiative cooling (RC) layer that passively enhances heat dissipation under natural convection. The device, fabricated using high-performance thermoelectric materials on a soft silicone substrate, maintained a total thickness of just 2.26 mm. Finite element modeling and experimental validation confirmed that the RC layer effectively increased the temperature gradient across thermoelectric legs, significantly improving the output power compared to conventional graphite-based or no-cooling designs. The FTEG achieved a maximum normalized power density of 3.51 μW/cm2 under temperature conditions representative of wearable use (T<inf>skin</inf> of 32 °C and T<inf>ambient</inf> of 26 °C). The harvested energy was then stored using a power management circuit and capacitor. This stored energy was successfully used to power a Bluetooth Low Energy (BLE) sensing module, enabling stable wireless transmission driven entirely by body heat. These results highlight the practical potential of integrating passive radiative cooling into flexible thermoelectric systems, paving the way for high-performance, battery-free wearable electronics and autonomous IoT applications.
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Laser-Carved Legacy: Exploring the Scientific Construction and Cultural Significance of the World’s Largest Golden Buddha in Thailand Through a Tourist Perspective
(2025-10-01)
White, Pattarinee
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Phae-Ngam, Wuttichai
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Kamoldilok, Surachart
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Naemchanthara, Kittisakchai
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Limsuwan, Pichet
This research investigates the intersection of construction innovation and cultural heritage through the lens of tourist perceptions of the world’s largest carved golden Buddha, situated at Khao Chi Chan Mountain, Pattaya, Thailand. Positioned as an emerging tourism destination, this site contributes to the rebranding of Pattaya as a globally significant hub for religious tourism. This study highlights how this monumental Buddha statue fosters spiritual experiences, promotes the conservation of art and culture, and encapsulates a historical narrative tied to Thailand’s royal lineage. Notably, the statue’s creation employed a pioneering technique—the only one of its kind worldwide—involving laser-guided carving by artisans, followed by gold leaf application to enhance its aesthetic magnificence. A mixed-methods research approach was adopted, integrating historical document analysis with narrative accounts of the statue’s construction using modern technology, complemented by quantitative data collected through tourist questionnaires. By documenting the historical use of laser technology in creating this iconic Buddhist landmark, this research corrects misconceptions about its construction process and highlights the innovative application of a 20 W Argon ion laser for drawing the image of Buddha on the cliff. This study evaluates tourist perceptions using the DHARMA model, revealing how Destination Identity, Heritage Values, and Memorable Experiences foster emotional connections and spiritual enrichment (β = 0.801, p < 0.001). The findings underscore Khao Chi Chan’s potential to reposition Pattaya as a hub for Buddhist tourism, diversifying its image beyond nightlife-centric tourism. This work contributes to sustainable tourism by demonstrating how sacred sites can balance cultural preservation and economic vitality, offering insights for heritage management and urban tourism development in Southeast Asia.

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