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The presence of point defects associated with shallow traps has been identified as a limiting factor in the design of materials with desirable characteristics for applications such as scintillation and luminescence dosimetry, among others. In this context, this study aims to elucidate the dynamics inherent to the charge carriers in systems containing multiple traps and one single recombination centre. To unravel this complexity, we employed a synergetic approach combining Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) measurements with kinetic models. Specifically, for the Li and Ce co-doped MgB 4 O 7 , we verified that the electron population trapped in shallower traps exhibits a slower decay rate under optical stimulation compared to deeper traps. This behaviour led to a delay in the luminescence emission, as a result of charge re-trapping or even competition with other centres. This phenomenon can be attributed to its low photoionization cross-section associated with a high re-trapping rate, providing a rationale for these remarks. In addition, we observed that the shallow traps have a greater optical than thermal probability of being detrapped, indicating that they were not solely detrapped through thermal stimulation. Also, the magnitude of the thermal probability leads us to believe that there is an electron population different from zero in the conduction band at t = 0 (before optical stimulation). Lastly, this study paves the way for a deeper understanding of charge carrier dynamics in systems of multiple traps, improving the performance of existing materials for scintillation and dosimetry. • The electron populations trapped in shallower traps exhibited a slower decay rate under optical stimulation compared to intermediate and deep traps. • Shallow traps have a low photoionization cross-section and high probability of re-trapping. • Intermediate traps have a low probability of re-trapping, compared to shallow and deep traps. [ABSTRACT FROM AUTHOR]

A method for determining thallium in water samples via solid sampling high-resolution continuum source graphite furnace atomic absorption spectrometry (SS HR-CS GF AAS) after preconcentration using chromatographic filter paper as a solid support was proposed. The effects of pH, stirring time, and sample volume in the analyte preconcentration step were studied. The presence of potential interferences in the sample and the type of masking agent were also examined. In the proposed procedure, the sample was placed in contact with the solid phase in a polypropylene tube, and after stirring for 3 min, thallium determination was performed via HR-CS GF AAS directly on chromatographic filter paper. A preconcentration factor of 55, a precision of 9.4% (n = 10; 10 μg L−1), a limit of detection of 0.018 μg L−1, and a limit of quantification of 0.059 μg L−1 were achieved. Analyte addition and recovery tests were performed, and the results ranged from 91% to 110%. The accuracy of the method was evaluated by analyzing a water reference material. The procedure was used to determine thallium in water samples collected in Barreiras, Bahia, Brazil. The results were compared with those obtained using inductively coupled plasma‒mass spectrometry (ICP‒MS). Thallium concentrations in the analyzed samples ranged from <0.059 to 0.80 μg L−1. [Display omitted] • A method for Tl determination in water samples using SS HR-CS GF AAS is presented. • Thallium preconcentration using chromatographic filter paper as a solid phase was performed. • Thallium determination was carried out via HR-CS GF AAS directly on chromatographic paper. • This method was used to analyze river water samples. [ABSTRACT FROM AUTHOR]

BeO ceramics in the wurtzite (w -BeO) form either pure or doped with lanthanide ions present high Thermoluminescence (TL) and Optically Stimulated Luminescence (OSL) sensitivity. However, the mechanism of defect formation governing the charge carrier dynamics associated with the TL and OSL signals is not well understood yet. Thus, this work aims to develop a study on the structural, mechanical, dielectric, and defect properties of Europium ion–doped w -BeO ceramics. We develop a new set of potential parameters to describe the Be–O bond. By using these potential parameters, we describe the physical and chemical properties with good agreement. Defect calculations employing the Mott and Littleton two-region strategy show that the distorted structure of pure w -BeO ceramics favours the Frenkel–type defect formation in the basal plane of the crystal lattice. When doped with Eu3+, we observed a change in the defect arrangement. It replaces preferentially two Be sites, eliminating beryllium interstices and keeping the beryllium vacancy from the initial configuration. We also observed that it is unlikely the Eu3+/Eu2+ coexist due to the solution energy values. Lastly, we have observed a most significant electron–hole interaction which may be associated with the intrinsic luminescence band of the w -BeO ceramics. In addition, TL and OSL measurements are presented to corroborate the defect calculations. The results presented here bring new insight to elucidate the charge carrier dynamic associated with the luminescent properties. [ABSTRACT FROM AUTHOR]

• Salicylic, gibberellic and abscisic acid influences the minerals absorption in salvia. • The application of growth regulators favored the production of photoassimilates. • Aplication of support vector machine for the exploratory analysis of Salvia samples. • Salvia samples were classified based on elemental composition, total flavonoids, and phenolic or agronomic variables. The objective of this work was to evaluate the influence of different growth regulators on the mineral and total phenolic contents of Salvia officinalis. The samples received the applications of salicylic acid (AS); gibberellic acid (GA 3); abscisic acid (ABA) and solution without regulators (control). The exploratory evaluation of the samples was carried out through the Principal Component Analysis (PCA). In addition, has been used supervised learning methods with support vector machine (SVM) algorithms to classify the samples. The phenolic and total flavonoid contents were higher in the plants treated with the regulators. The element found in the highest concentration in Salvia officinalis was N. Plants sprayed with ABA showed higher concentrations of N, K, and Mn; Fe and Al were higher with ABA and gibberellin application, while the application of AS provided the highest accumulation of P. The application of plant regulators improves the nutraceutical properties of Salvia officinalis. [ABSTRACT FROM AUTHOR]