ADEMAR JOSE POTIENS JUNIOR
34 resultados
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Artigo IPEN-doc 28179 A desktop application for automatic gamma spectroscopy analysis with deep learning2021 - OTERO, ANDRE G.L.; POTIENS JUNIOR, ADEMAR J.; LINO, JULIANA dos S.; MARUMO, JULIO T.Artigo IPEN-doc 26215 Retrieval and conditioning of radium sources-containing package in Panama2019 - MOURÃO, ROGERIO P.; SILVA, EDSON P. da; FERREIRA, MARCIO D.C.; POTIENS JUNIOR, ADEMAR J.A team of CNEN experts successfully conducted an operation in Panama to recover and condition disused radioactive sources stored in an unsafe condition. The sources, containing the Ra-226 isotope, were used in the past to treat tumors using the technique known as brachytherapy and were immobilized in a complex package buried in an old hospital wing destined for demolition. The compartment where the package stayed for decades, built under the floor of a hospital laboratory, was contaminated with radon and daughters, including Pb-210, responsible for the contamination found. The operation consisted of extracting the package from this compartment, placing it in a cylindrical metal overpack, transporting it to the temporary storage site and carry out site decontamination. Besides the package with the sources, three 200L drums containing contaminated debris from the demolition of walls and floor were generated. No relevant event of radiological protection, such as occupational dose above the established limits, contamination of personnel or place, etc, was observed. The package produced, together with those containing the contaminated debris, was transferred to the facilities of the National Oncology Institute.Artigo IPEN-doc 26211 Comparing deep learning architectures on gamma-spectroscopy analysis for nuclear waste characterization2019 - OTERO, ANDRE G.L.; POTIENS JUNIOR, ADEMAR J.; CALZETA, EDUARDO P.; MARUMO, JULIO T.Neural networks, particularly deep neural networks, are used nowadays with great success in several tasks, such as image classification, image segmentation, translation, text to speech, speech to text, achieving super-human performance. In this study, we explore the capabilities of deep learning on a new field: gamma-spectroscopy analysis, comparing the classification performance of different deep neural networks architectures. We choose VGG-16, VGG-19, Xception, ResNet, InceptionV3 and MobileNet architectures which are available through the Keras Deep Learning framework to identify several different radionuclides (Am-241, Ba- 133, Cd-109, Co-60, Cs-137, Eu-152, Mn-54, Na-24, and Pb-210). Using an HPGe detector to acquire several gamma spectra, from different sealed sources to created a dataset that was used for the training and validation of the neural networks comparison. This study demonstrates the strengths and weakness of applying deep learning on gamma-spectroscopy analysis for nuclear waste characterization.Artigo IPEN-doc 24161 Technical feasibility study on volumetric reduction of radioactive wastes using plasma technology2017 - PRADO, E.S.P.; DELLAMANO, J.C.; CARNEIRO, A.L.G.; SANTOS, R.C.; PETRACONI, G.; POTIENS JUNIOR, A.J.The radioactive waste arising from nuclear reactors, hospitals, industry and research institutes are generated daily with a considerable amount. To final dispose of these radioactive waste safely and cost effectively, they must be transformed into physical and chemical compounds suitable for radionuclides immobilization with maximum volume and exhaust gaseous reduction. In this scope, among the promising technologies for the radioactive waste treatment, plasma technology allows reducing substantially the waste volume after exposing them to temperatures above 2,500ºC. In the planning and management of radioactive waste, the challenges related to plasma technology are presented as a motivation factor for the possible implantation of plasma reactors in nuclear plants and research centers aiming at improving the process of radioactive waste management.Artigo IPEN-doc 24092 Studies of equilibrium and kinetics of adsorption of cesium ions by graphene oxide2017 - OLIVEIRA, FERNANDO M.; BUENO, VANESSA N.; OSHIRO, MAURICIO T.; POTIENS JUNIOR, ADEMAR J.; HIROMOTO, GORO; RODRIGUES, DEBORA F.; SAKATA, SOLANGE K.Cesium is one of the fission products of major radiological concern, it is often found in nuclear radioactive waste generated at nuclear power plants. Graphene Oxide (GO) has attracted great attention due to its functionalized surface, which includes hydroxyl, epoxy, carbonyl and carboxyl groups, with great capacity of complexation with metal ions and can be used as adsorbent to remove cations from aqueous solutions. In this work, a treatment of radioactive waste containing 137Cs was studied. For the batch experiments of Cs+ removal, 133Cs concentrations remained after the adsorption were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and the results obtained were analyzed according to the Langmuir and Freundlich isotherms models. The kinetics of adsorption and Gibbs free energy were also determined. The Langmuir model was the best fit and defined a favorable adsorption. The cesium adsorption process is the pseudo-second model and the Gibbs free energy calculation indicated that the adsorption process is spontaneous.Artigo IPEN-doc 22367 Comparison of a KAP meter and a PDC behaviour using mathematical simulation in reference diagnostic radiology qualities2014 - POTIENS JUNIOR, A.J.; COSTA, N.A.; SANTOS, L.R.; CORREA, E.L.; VIVOLO, V.; POTIENS, M.P.A.Artigo IPEN-doc 22283 Estudo das isotermas de adsorção e constante de distribuição par a remoção de sup(241)Am em rejeitos radioativos líquidos com magnetita2014 - OSHIRO, M.T.; SAKATA, S.K.; POTIENS JUNIOR, A.J.Artigo IPEN-doc 21129 Characterization of the water filters cartridges from the IEA-R1 reactor using the Monte Carlo Method2015 - COSTA, PRISCILA; POTIENS JUNIOR, ADEMAR J.Artigo IPEN-doc 21026 XRD and SEM/EDS characterization of coconut fibers in raw and treated forms used in the tratment of strontium in aqueous solution2015 - FONSECA, HEVERTON C.O.; GARCIA, RAFAEL H.L.; FERREIRA, ROBSON J.; SILVA, FLAVIA R.O.; POTIENS JUNIOR, ADEMAR J.; SAKATA, SOLANGE K.Artigo IPEN-doc 19386 Implementation of a computerized system for the management of radioactive lightning rods and smoke detectors2013 - NASCIMENTO, RAFAEL A. do; DELLAMANO, JOSE C.; POTIENS JUNIOR, ADEMAR J.