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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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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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Synthesis of Fe–Cu Alloys via Ball Milling for Electrode Fabrication Used in Electrochemical Nitrate Removal from Wastewater
(2025-07-01)
Hayeedah, Hannanatullgharah
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Sakulkalavek, Aparporn
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Klongratog, Bhanupol
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Somdock, Nuttakrit
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Srirach, Pisan
Fe and Cu powders were mixed at a 50:50 ratio. Then, Fe-Cu alloys were prepared using the ball milling technique with different milling times of 6, 12, 18, 24, 30, 36, and 42 h. The crystalline structure was analyzed using X-ray diffraction (XRD), and it was found that the optimum milling time was 30 h. The homogeneity of the Fe and Cu elements in the Fe–Cu alloys was analyzed using the scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDX) mapping technique. Additionally, the crystal orientation of the Fe–Cu alloys was investigated using transmission electron microscopy (TEM). To fabricate the cathode for nitrate removal via electrolysis, an Fe–Cu alloy milled for 30 h was deposited onto a copper substrate using mechanical milling, then annealed at 800 °C. A pulsed DC electrolysis method was developed to test the nitrate removal efficiency of the Fe–Cu-coated cathode. The anode used was an Al sheet. The synthesized wastewater was prepared from KNO<inf>3</inf>. Nitrate removal experiments from the synthesized wastewater were performed for durations of 0–4 h. The results show that the nitrate removal efficiency at 4 h was 96.90% compared to 74.40% with the Cu cathode.

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