The Khorat Plateau is Thailand's largest uranium-bearing region and is well known for its Mesozoic sandstone-hosted uranium deposits and abundant dinosaur fossil localities. Recent studies have identified naturally radioactive fossils formed through the incorporation of naturally occurring radionuclides during fossilization and post-burial diagenesis. However, the implications of this natural radioactivity for occupational exposure during fossil excavation and handling remain poorly understood. This study presents the first comprehensive radiological assessment of Thailand's dinosaur fossil excavation sites by combining long-term field monitoring with laboratory characterization of naturally occurring radioactive materials (NORM). Field investigations were carried out at the indoor Phu Wiang (Khon Kaen Province) and outdoor Phu Noi (Kalasin Province) excavation sites. Ambient gamma dose rates measured using optically stimulated luminescence dosimeters ranged from 0.052 to 0.171 mu Sv & centerdot;h(-1), while radon concentrations measured using RADUET CR-39 detectors ranged from 3.158 to 74.012 Bq & centerdot;m(-3), with generally higher values during winter. One-way ANOVA showed significant seasonal variation in radon concentrations at the Phu Noi site (p-value < 0.001), whereas no significant seasonal difference was found at the Phu Wiang site (p-value = 0.129). High-purity germanium gamma-ray spectrometry of 33 soil samples yielded mean activity concentrations of 41.14 +/- 11.55 Bq & centerdot;kg(-1)for(226)Ra, 54.80 +/- 14.82 Bq & centerdot;kg(-1)for(232)Th, and 965.89 +/- 313.81 Bq & centerdot;kg(-1)for(40)K. Gamma dose rates measured from 37 fossil specimens differed significantly between the two excavation sites (Welch'st-test, p-value < 0.001), suggesting localized radionuclide enrichment during fossilization. Although some measured values exceeded worldwide average background levels, the estimated occupational radiation doses remained below internationally accepted protection limits. These findings support routine radiation monitoring, adequate ventilation, and appropriate work planning, particularly in enclosed environments. This study provides the first scientific basis for radiation protection and safety management at Thailand's dinosaur fossil excavation sites.
Using fruit waste as a dye adsorbent is another option to achieve environmental sustainability in terms of waste management, along with wastewater treatment. This study aimed to synthesize new adsorbents from durian shell and pineapple peel wastes, called durian shell powder (DP) and pineapple peel powder (PP), to investigate their performance for rhodamine B dye (RhB) adsorption, including their characterizations, adsorption isotherms, kinetics, and thermodynamic studies. Both DP and PP had amorphous structures, and their surfaces were coarse and heterogeneous. Carbon (C), oxygen (O), calcium (Ca), hydroxyl (O–H), methyl or methylene (C–H), carbonyl (C=O), cyclic alkene (C=C), and carboxyl (C–O) were the main chemical elements and functional groups found in DP and PP. XPS results from a high-resolution scan demonstrated three main elements of O 1s, C 1s, and N 1s. The pH pzc values of DP and PP were 2.96 and 2.67. DP demonstrated a higher RhB removal efficiency and adsorption capacity of 87.11% and 2.61 mg/g than PP at 72.18% and 1.44 mg/g by using a small adsorbent dosage, short contact time, and low temperature. Moreover, DP and PP could be reused for more than three cycles with high RhB removal efficiencies of 73.10% and 55.39%, respectively. Freundlich and pseudo-second-order kinetic models well explained their adsorption patterns and mechanisms relating to heterogeneous adsorption and pseudo-second-order behavior. Thermodynamic studies showed an exothermic process. Therefore, DP and PP were chosen as low-cost adsorbents with a simple synthesis method and moderate adsorption performance for RhB adsorption from fruit wastes.
Thermal deactivation and sintering remain critical challenges for nickel (Ni)-based catalysts in CO2 methanation (Sabatier reaction). In this study, highly dispersed Ni/TiO2 catalysts were synthesized via a citric acid (CA)-assisted solid-state method, leveraging the strong metal-support interaction (SMSI) of TiO2 to enhance catalytic stability. Optimization of the Ni:CA molar ratio revealed that a 1:2 ratio yielded superior Ni nanoparticle dispersion and strongest metal-support interaction, as confirmed by XRD, TEM, and H2-TPR, where a notable shift to higher reduction temperatures indicated strong Ni anchoring on TiO2. The optimized 20 wt% Ni/TiO2 catalyst achieved high CO2 conversion with near 100% CH4 selectivity below 350 °C and demonstrated exceptional durability with no measurable activity loss over 60 h of continuous operation. In-situ X-ray absorption spectroscopy performed under realistic reaction conditions, including fluctuating gas compositions simulating dynamic operational stress, provided direct real-time mechanistic insight. In-situ (X-ray absorption near edge structure) XANES confirmed complete formation and preservation of metallic Nio active sites during activation, while (Extended X-ray absorption fine structure) EXAFS revealed negligible structural changes under fluctuating conditions, confirming effective sintering suppression. These results conclusively establish that the synergistic combination of CA chelation-controlled Ni dispersion and robust TiO2-SMSI collectively preserves the active Nio centers under demanding conditions, offering a practical strategy for designing thermally stable, high-performance Ni-based catalysts for efficient CO2 utilization.
The introduced investigation demonstrates an extensive finite element analyzation in order to explore thermal transportation features of engine oil enriched with triadic hybrid Nano-size particles exposed to 3D inclined plate incorporated with non-Fourier thermal conduction combine with thermal radiation influence. The mathematical modeling is established by incorporating thermal relaxation impacts to attain definite thermal wave speed, which are pivotal in high temperature and also in nanoscale thermal systems. For the realistic description radiative thermal flux, non-linear thermal radiation is invoked exposed to high temperature gradients. The acquired coupled comprehensive partial differential equations specified by momentum as well as energy transport are modified into a weak variational structure and numerically solution is obtained by utilization of robust finite element approach. The impacts of key physical constraints, including Nano-scale particle volume fraction, radiation as well as also thermal relaxation constraint and inclination angle across temperature compartment and also thermal transportation rate is discussed in detail. Attained outcomes depicts that the inclusion of triadic hybrid Nano size particles considerably intensifies thermal efficiency in contrast to conventional fluids, whilst non-Fourier features moderate thermal propagation closed to the plate surface. The proffered examination highlights the collective role of Nanoscale synergy and also modified thermal conduction theory in enhancing thermal management particularly of lubricated mechanical systems.
Room-temperature Na-S batteries (RT-NSBs) hold great promise for high-energy-density storage, but their practical deployment remains hindered by polysulfide dissolution (i.e., shuttle effect), sluggish sulfur redox reactions (SRR), and limited ionic transport. Rational design of electrocatalysts with a strong adsorption affinity toward polysulfides and high catalytic activity is therefore essential to address these issues. In this work, we employ density functional theory (DFT) to investigate N-, O-, and dual (N, O)-doped MoS2 as potential electrocatalytic cathode hosts for RT-NSBs. Unlike most previous studies that solely assessed Na2Sn adsorption in the gas phase, we utilized an implicit solvent model to incorporate intrinsic electrolyte effects on polysulfide stability. We show that this approach yields lower Na2Sn binding energies on the cathode hosts as compared with the gas-phase approach due to solvent polarity and dielectric screening, indicating the importance of solvation in evaluating polysulfide dissolution. N-, O-, and (N, O)-doped MoS2 exhibit sufficiently strong Na2Sn adsorption to mitigate the shuttle effect. Nevertheless, their catalytic behaviors differ considerably. While N- and O-doped MoS2 (monodoped MoS2) provide limited SRR enhancement, (N, O)-doped MoS2 delivers significantly improved catalytic activity. This is attributed to the significant population of antibonding states in the N-Na and O-Na bonds formed at the interface of (N, O)-doped MoS2 and Na2Sn, inducing s- and p-band shifting after interacting with Na2Sn to catalytically activate the conversion of Na2Sn in the SRR. Kinetic analysis quantitatively shows that (N, O)-MoS2 markedly lowers the rate-determining barrier of the SRR from 0.93 eV in pristine MoS2 to 0.57 eV. These results identify (N, O)-doped MoS2 as a highly effective cathode host for RT-NSBs.
