[en] We obtain, by starting from the balance laws of a continuum endowed with a vectorial microstructure and with a suitable thermodynamics, the evolution equation for the excitation carriers in scintillating crystals. These equations, coupled with the heat and electrostatic equations, describe the non-proportional response of a scintillator to incoming ionizing radiations in terms of a reaction and diffusion-drift system. The system of partial differential equations we arrive at allows for an explicit estimate of the decay time, a result which is obtained here for the first time for scintillators. Moreover, we show how the two most popular phenomenological models in use, namely the kinetic and diffusive models, can be recovered, among many others, as a special case of our model. An example with the available data for NaI:Tl is finally given and discussed, showing how these models depend on the energy of ionizing radiations. (author)

No abstract available

[en] In this work, the Digital Tangential Radiography Technique was used to detect and determine the lost wall thickness of coated steel tubes, which had defects intentionally manufactured in their steel structure, with the aim of verifying limitations of the technique for determining the lost wall thickness (depth of defects).

[en] The objective of this work is to evaluate the digital radiography technique for Double View Double Wall (PDVD) of weld beads, regarding the ability to visualize defects. For comparison purposes, μCT of the same specimens was performed, making it possible to verify how many defects the digital radiographic technique was unable to identify

[en] Functional foods contain in their composition some biologically active substances that when added to a usual diet produce metabolic or physiological processes, resulting in disease risk reduction and health maintenance. Acai, green tea, quinoa, chia, flaxseed and goji berry are examples functional foods due to their health benefits. The concentrations of Br, Ca, Co, Cl, K, Fe, Mn, Mg, Na, Rb and Zn were determined in quinoa, chia and flaxseed samples by Neutron Activation Analysis. The obtained results were discussed using the Dietary Reference Intake (DRI) for essential elements provided by the Institute of the Medicine of National Academy and a comparison between the different functional foods was carried out. (author)

No abstract available

[en] X-rays are a form of radiation of fundamental importance in a wide variety of applications, and among them is the microcomputed tomography (microCT). MicroCT is a nondestructive technique used in many industrial and research areas such as geology, archaeology and biomedicine. In this work the spectra of the v|tome|x m tomographer were acquired and analyzed in order to better understand the energy spectra of a microCT X-ray tube. A semiconductor detector, model XR-100 CdTe, was used for data acquisition. Energy spectra were acquired using different filtering and tube voltage configurations. Filtering systems were comprised of aluminum and copper metallic filters. Unfiltered spectra acquisition was performed for tube potential ranging within 20-80 kV, and filtered spectra at tube voltage of 40-120 kV, with a 10 kV step. Results also include average energy values of unfiltered and filtered beams for tube potential of 40-120 kV, as well as the attenuation value of 60 kV and 70 kV related spectra regarding each of the filtering systems, which altogether enabled the evaluation of how the use of filters impact X-ray tube energy spectra. (author)

No abstract available

No abstract available

[en] The present work aims to use a convolutional neural network algorithm to assist in evaluating the quality of weld beads. The work methodology consists of three stages: pre-processing, a stage in which the images of the learning weld beads are modified to be the input neurons; development, the moment in which the neuronal architecture is structured; and post-processing, a phase in which the model is tested using precision, recall, F1 metric and accuracy metrics. The results showed an accuracy greater than 90% for discontinuity detection as well as good precision and recall results