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Microplastics and POPs on the Southwestern Atlantic deep-sea floor
2025 - STEFANELLI-SILVA, GABRIEL; MELO, MARCELO R.S. de; PASCOAL, DIEGO R.C.; DIPOLD, JESSICA; WETTER, NIKLAUS U.; FREITAS, ANDERSON Z.; TANIGUCHI, SATIE; MONTONE, ROSALINDA C.; SUMIDA, PAULO Y.G.
The deep sea is a historical sink for litter, but efforts to assess the human footprint in this ecosystem are relatively recent. Building upon previous works on the continental margins of the Southern Hemisphere, this study presents the first report of microplastics (MPs) and persistent organic pollutants (POPs) for the Southwestern Atlantic deep-sea floor. Ingestion of MPs by benthic invertebrates, and contamination by polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in demersal teleostean fish and sediments were recorded in the central Santos Basin, along the Brazilian continental slope, between 400 and 1503 m depth. Individuals from 9 invertebrate species (n = 61 organisms) had their gut content examined, with 3 species ingesting anthropogenic particles shaped like fibers (n = 23 fibers). The sea cucumber Deima validum was the most contaminated species, with 1.64 ± 0.70 fiber individual􀀀 1, and 54.54 % of individuals ingesting fibers. Five fibers were identified as MPs, composed of polyamide, polyacrylonitrile, polyaryletherketone, polystyrene and polysulfide synthetic rubber. Total PCBs in the fish (n = 14 organisms) ranged from 519 to 7636 ng g􀀀 1 (lipid weight), and from 1.28 to 3.96 ng g􀀀 1 (dry weight) in the sediments. Among the PBDEs investigated, only BDE-47 and BDE-99 were found, and only in the fish. While additional work is needed to ascertain the possible origin and ecological implications of MPs and POPs found at the bottom of the ocean, this study provides critical data on pollution levels for the deep-sea community of Southeastern Brazil.
Engineered nanoparticles enhance photodynamic inactivation against the WHO fungal priority pathogens
2025 - SILVA, ABDENEGO R. da; RAPOSO, BRUNO L.; LIMA, GEYES S. de; BUENO-JANICE, JACQUELINE C.; SELLERA, FABIO P.; CABRAL FILHO, PAULO E.; FONTES, ADRIANA; RIBEIRO, MARTHA S.
Fungal infections pose a significant global health concern, prompting the WHO to prioritize fungi needing novel therapies. Photodynamic inactivation (PDI), which uses light, a photosensitizer (PS), and oxygen to produce oxidative stress, has shown promising results against fungi. Engineered nanoparticles (NPs) have emerged as a promising ally to enhance PDI. This systematic review examined the combined effects of PDI and NPs on the WHO's priority fungal pathogens. After screening Embase, Pubmed, Scopus, and Web of Science, ten studies were selected based on criteria including consistent NP characterization, PDI protocol, and a focus on critical and high priority fungi. Most studies targeted Candida albicans, with only one of them on Fusarium keratoplasticum. Only 4 studies reported the effects of PDI mediated by NPs on biofilms. Nanostructures applied included metallic, superparamagnetic iron oxide, micelle, and polymeric NPs. Findings indicate that i-) NPs can enhance the solubility of PSs by carrying hydrophobic compounds; ii-) NPs may improve the chemical stability of PSs avoiding aggregation, which could reduce the PS performance; iii-) NPs can be engineered to reduce the required PS concentration for effective fungal elimination, and iv-) Metallic NPs can improve the photophysical properties of PSs, such as enhancing the generation of reactive oxygen species by localized surface plasmon resonance. Further research is needed to extend these findings beyond in vitro conditions.
Er3+-doped BaY2F8 for non-contact lifetime thermometry
2026 - TANNUS, DANILO D.; ANDRADE, ADRIANO B.; BISPO, GIORDANO F.C.; BALDOCHI, SONIA L.; MACEDO, ZÉLIA S.; VALERIO, MÁRIO E.G.
This work presents a luminescence thermometry system based on a programmable electronic module designed for precise control of excitation pulses using a UV LED source, enabling time-resolved measurements of luminescence lifetime. This system was applied to investigate the influence of dopant concentration on the luminescence lifetime of Er3+ ions in a barium and yttrium fluoride matrix (BaY2F8) doped with different concentrations (1, 2, and 3 mol%) and their possible effects on thermometric usage. Spectroscopic measurements revealed that the sample with 3 mol% of Er3+ exhibited the highest luminescence efficiency, without evidence of concentration quenching. The luminescence lifetime decreased with increasing temperature, which was attributed to the increase in nonradiative de-excitation processes observed for all samples. The relative thermal sensitivity (Sr) was obtained from the lifetime dependence on temperature with the 3 mol% Er3+-doped sample presenting the highest Sr, reaching 0.36 % K􀀀 1 at 317 K, indicating its potential usage as a non-contact luminescent thermometer. The measurements were performed via an electronic module specifically developed for excitation and lifetime-based luminescence detection, allowing precise control of the excitation pulse parameters. The repeatability of the measurements reached approximately 98 %, confirming that the sensor is stable and highly reproducible. The results demonstrate that lifetime-based luminescence thermometry using Er3+-doped BaY2F8, combined with a programmable electronic module for precise excitation and detection control, provides a robust and accessible approach for temperature sensing, reducing the dependence on complex excitation sources, such as lasers, and increasing flexibility in data acquisition.
Effect of Ce3+ doping on the structural, optical, and dosimetric properties of magnesium-borate glasses
2025 - BERRERA, GERARDO R.; ALMEIDA, ADRIEL S.; VIDIGAL, BRUNO M.; SILVA, ANDERSON M.B.; NUNES, MATHEUS C.S.; NOVAIS, ANDREA L.F.; TRINDADE, NEILO M.; SOUZA, DIVANIZIA N.
Ce3+ doped magnesium-borate glasses with compositions 80MgB2O4-20MgB4O7:xCe and 60MgB2O4-40MgB4O7:xCe (where x = 0.10, 0.30, 0.50, 0.70, and 0.90 wt%), were successfully synthesized using the melt quenching method. The physical, structural, and luminescent properties of the glasses were systematically investigated through density measurements, X-ray diffraction (XRD), differential scanning calorimetry (DSC), optical absorption, spectrofluorometry, and optically stimulated luminescence (OSL). XRD patterns confirmed the amorphous nature of the glasses, while DSC provided insights into their thermal stability and phase transition behavior. The thermal stability of the 60 MBO matrix was found to be higher than that of the 80 MBO glass. An increase in glass density with higher Ce3+ concentrations was observed, accompanied by a reduction in molar volume. The indirect and direct optical band gap decreased with increasing Ce3+ content, correlating with the observed decrease in molar volume. Photoluminescence studies revealed emissions associated with Ce3+ ions incorporated into the glass matrix. Additionally, OSL measurements demonstrated the dose-response behavior of the glasses over the range of 0.02–5 Gy. Particularly, the 60MBO glass composition exhibited superior sensitivity to ionizing radiation compared to the 80MBO composition. The OSL signal of the 60MGO glass fades significantly within a few days. Long-term stability of the OSL signal should be a goal for new studies on these glasses.
Cancer mortality in workers at risk of occupational exposure to ionizing radiation in a company in the nuclear sector headquarters in São Paulo
2024 - VIEIRA, GLACY S.; MARTINEZ, MARIA C.; CARDOSO, MARIA R.A.
Objective: To compare cancer mortality among workers exposed to gamma and X radiation and the general population of the city of São Paulo, as well as that of the subgroup monitored with those not monitored for gamma and X radiation in a work unit with ionizing radiation based in the city of São Paulo. Methods: Between 2016 and 2021, a retrospective open cohort study was carried out with workers who were employed from 08/31/1956 to 12/31/2016 based on data collected at the company and in official institutions. Standardized mortality ratios (SMR) were calculated by sex, age and calendar period of cancers grouped according to type, risk factor and organ system in two analyses: in the external analysis, the mortality of the study population was compared with that of the general population of the city of São Paulo; In the internal analysis, the mortality of the monitored subgroup was compared with that of the subgroup not monitored for gamma and X radiation. Results: The external mortality analysis showed SMR=0.224 (95%CI 0.208–0.240) and the healthy worker effect, while the internal mortality analysis showed SMR=0.685 (95%CI 0.618–0.758). Conclusion: This study showed lower cancer mortality among exposed workers when compared to mortality in the general population and the healthy worker effect. Among workers monitored for gamma and X radiation, cancer mortality was lower when compared to those not monitored. © 2024 | Epidemio is a publication of Associação Brasileira de Saúde Coletiva-ABRASCO.
Effect of gamma radiation on human enamel chemical and physical properties
2025 - SILVA, POLLYANNA N.F da; BARCELLOS, MARIA C.F.; COSTA, FERNANDA C.; SILVA, CELIO dos S.; MANEA, SILVIO; GONÇALEZ, ODAIR L.; JARDIM, VITOR R.; MARTINS, GISLENE V.; LIMA, NELSON B.; FOUND, ANELYSE A.; SOUZA, GRACE M. de; KAMINAGAKURA, ESTELA; TANGO, RUBENS N.
Background: Gamma radiation is still used in developing countries for head and neck cancer treatment. Irradiated dental enamel undergoes dose-dependent chemical and mechanical changes that can hinder oral rehabilitation. Understanding these processes can be useful to professionals to plan safer long-lasting treatments. This study aimed to evaluate different doses of gamma radiation on the chemical and mechanical properties of human dental enamel. Methods: Sixty human third molars were divided into six groups (n = 10), according to dose: 0; 20; 40; 50; 60; or 70 Gy, in daily increments of 2 Gy. After irradiation, the composition and carbonate/ phosphate ratio (C: P) were evaluated by Fourier Transformed Infrared Spectroscopy (FTIR). X-ray diffraction (XRD) was used to evaluate crystal size (shape factor) and crystallinity. Hardness, elastic modulus, and scratch resistance were measured, and the microstructure was observed by scanning electron microscopy (SEM). Data of C: P, crystallinity (%), shape factor (nm), hardness (VHN - Vickers Hardness Number), and elastic modulus (GPa - Gigapascals) were submitted to analysis of variance and to Tukey’s test (α = 0.05). Results: FTIR showed carboxylic acid in the irradiated groups and an increase in C: P for the 70 Gy group (p = 0.015), but with no change in crystalline structure. A significant decrease was observed in the values of hardness (p = 0.0000) and the elastic modulus (p = 0.0000) in the irradiated groups. For scratch test, the 60 and 70 Gy groups showed lower values for initial spallation. SEM showed spaced rounded peaks of enamel prisms in the 60 and 70 Gy groups. Conclusions: Gamma radiation negatively affected the chemical and physical properties of human enamel. Trial registration: Plataforma Brasil, CAAE: 66495417.1.0000.007. © The Author(s) 2025.
Innovative sample preparation method using a conductively heated digestion system for trace element analysis of radioactive oil sludge by ICPOES
2025 - PINTO, ALINE L. M.; SOUZA, ALEXANDRE L. de; ARAUJO, LEANDRO G. de; MARUMO, JULIO T.; COTRIM, MARYCEL E.B.; GUILHEN, SABINE N.
This study presents a novel and efficient sample preparation method based on conductively heated digestion in closed vessels (CHDS), employing collagen capsules as a transfer medium. The method was specifically developed for the treatment of oil sludge-a complex waste product generated by the oil industry, typically composed of hydrocarbons, water, sediments, processing residues, and radionuclides from the uranium-238 and thorium-232 decay chains. Compared to conventional open-vessel digestion techniques using heating blocks, this approach offers several advantages, including reduced sample and reagent volumes, significantly shorter preparation times, and minimized contamination risks. Trace element concentrations in the digested samples were determined by inductively coupled plasma optical emission spectrometry (ICP-OES).
Photobiomodulation therapy and 5% minoxidil in female pattern hair loss
2025 - RODRIGUES, DENISE F.; CORTEZ, GABRIEL L.; BAGATIN, EDILEIA; NASCIMENTO, MAURICIO M. do; RIBEIRO, MARTHA S.
Purpose Female pattern hair loss (FPHL) is a major concern for women experiencing hair thinning. While minoxidil 5% (MIN) is a medically approved treatment and photobiomodulation therapy (PBMt) has shown effectiveness in stimulating hair growth, treatments typically last 24 weeks. This study aimed to evaluate the effects of combining PBMt with topical MIN for treating FPHL within a shorter 12.5-week timeframe, focusing on hair growth phases. Methods Nine women aged 30 to 50 years with FPHL participated. They applied MIN twice daily to the scalp throughout the treatment period. In the clinic, hair was sectioned, and one side of the scalp was randomly assigned to receive 25 sessions of red laser (100 mW, 4 J/point), delivered at 15 evenly spaced points. Treatments were administered twice a week, while the opposite side received sham irradiation. Standardized photographs, a quality of life (QoL) questionnaire, and phototrichograms were used to evaluate the outcomes. Results Both the MIN and PBMt + MIN groups showed significant improvements in QoL scores and hair density. Additionally, both groups experienced increased hair density and a higher percentage of hairs in the anagen phase. Remarkably, the PBMt + MIN group exhibited a significantly greater reduction in telogen-phase hairs. Conclusion These findings suggest that PBMt may enhance MIN therapy for FPHL, particularly in reducing telogen-phase hair counts within a shorter treatment period. Clinical trial number Not applicable.
Effects of surface preparation on the corrosion resistance of TSA anodized aluminum alloys
2025 - PEREIRA, BRUNO N.; ARAUJO, JOAO V de S.; KLUMPP, RAFAEL E.; ANTUNES, RENATO A.; COSTA, ISOLDA
This study examines the impact of surface preparation on the corrosion resistance of anodized AA2198-T851 aluminum alloy. Two pretreatment methods were employed: (i) alkaline degreasing in 10 wt.% NaOH at 60 °C followed by de-smutting in 30 vol.% HNO3, and (ii) etching in an oxidizing acidic solution (K3 Smutt-Go, 7 V, 20 °C) intended to remove copper-containing intermetallic particles. Surface preparation methods were analyzed using SEM, FEG-SEM, SEM-EDS, and XPS. Corrosion resistance was tested through EIS, and NSST. All electrochemical tests were conducted in 0.1 mol L−1 NaCl solution, and the NSST followed ASTM B117-16. The findings show that removing intermetallic particles greatly improves the corrosion resistance of TSA-anodized AA2198-T851. Among the tested conditions, the etched samples exhibited superior performance, showing no observable corrosion after 336 hours of salt spray exposure, confirming their enhanced corrosion resistance.
Development of a porous 304L Stainless steel substrate enhanced with graphene and platinum for hydrogen mitigation in passive autocatalytic recombiners
2025 - MICHELI, de L.; SILVESTRIN, G.; SOUZA, R.F.B de; OLIVEIRA NETO, A.; GIOVEDI, C.
The rapid expansion of the hydrogen economy poses significant safety challenges related to hydrogen handling across a wide range of applications. This study investigates the feasibility of using porous sintered 304 L stainless steel, coated with graphene and doped with platinum, as an advanced material for passive autocatalytic recombiners (PARs) to mitigate hydrogen release and improve operational safety. Detailed characterization using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy confirmed the uniform deposition of graphene and platinum layers, as well as structural features such as spinel phase segregation. The low surface wettability, attributed to the armchair configuration of graphene edges, further enhances the material’s suitability for catalytic recombination reactions in humid environments. Hydrogen removal tests demonstrated that an optimized platinum doping level of 0.5 wt% combined with a controlled substrate porosity of 50 µm resulted in a maximum hydrogen conversion efficiency of 40 %. These results highlight the critical influence of doping concentration and pore architecture on catalytic performance and overall PAR efficiency. Overall, this research provides valuable insights into the development of high-performance, passive hydrogen recombination systems, offering a promising pathway to improve safety and sustainability in emerging hydrogen technologies and to advance the hydrogen industry.
Photobiomodulation in the parotid and submandibular glands
2025 - CORREA, LUCIANA; MEIRELLES, LIS; CARNEIRO, REGINA C.G.; SILVA, FÁBIO F.A. da; WISOTZKY, ERIC L.; BERROCAL, EDOUARD
There are ongoing questions about the most effective wavelength for photobiomodulation (PBM) on major salivary glands due to the specific anatomical location and unique optical properties of the tissues surrounding the glands. The aim of this study was to analyze the photon propagation in the major salivary glands region of humans and rats using Monte Carlo (MC) stochastic simulation. Phantoms were designed to replicate the tissues surrounding the parotid and submandibular glands in humans and rats. Simulations were carried out using a MC online platform with wavelengths of 525 nm, 660 nm, and 850 nm. An experimental assay in rats was conducted to evaluate if the wavelength with the best performance could enhance the salivary flow. The 525 nm photons were primarily absorbed by the skin and fat tissue of humans and rats. Only in rats, this wavelength reached the salivary glands. The 660 nm photons reached the human glands but were more absorbed in the submandibular gland than in the parotid gland. The 850 nm photons had a higher absorption in both human and rat parotid glands. PBM using 850 nm wavelength improved the salivary flow in rats. The 660 nm and 850 nm wavelengths were more effectively absorbed in the human parotid and submandibular glands, respectively, compared to the 525 nm. The increased salivary flow observed in rats following treatment with 850 nm suggests a beneficial effect of this wavelength on salivary gland function. Clinical trial number: Not applicable.
Large mesopore FDU‑ 12 silica for papain encapsulation
2025 - CIDES DA SILVA, L.C.; LOSITO, D.W.; PIMENTEL, D.R.O.; ANDREO FILHO, N.; MARTINS, T.S.; OTUBO, L.; SANT'ANNA, O.A.; FANTINI, M.C.A.
The usual synthesis of face-centered cubic FDU- 12 mesoporous silica reported in the literature does not mention the role of some experimental conditions that govern its structural and textural properties. In particular, the order of introducing the silica source into the reaction medium, the closing of the recipient setup, the concentration of the swelling agent, as well as the more researched influence of heat treatment on the material characteristics. In this study, the results indicated that the homogenization of F127 and TMB is essential before the introduction of TEOS into the reaction chamber to obtain a more ordered porous structure. This, together with maintaining the nominal concentrations of all chemical compounds by properly isolating the reaction chamber from the outside atmosphere, was crucial. The evaluation of TMB concentration revealed that the increase of TMB resulted in increased surface area, pore volume, and size, leading to entrance pores of different sizes, related to different amounts of TMB inside the F127 micelles. The best structural/textural results were achieved by a hydrothermal treatment (HT) of 100 °C, while higher HT increased pores sizes, but it raised disorder. Finally, the papain incorporation in the silica matrix preserved its catalytic properties and induced better catalytic activity, with around 42% higher efficiency than the isolated enzyme. The evaluation of papain delivery showed rapid release within one hour, followed by a slow, continuous release over time, finishing in 1 h.
Silicon nitride porous ceramics prepared by sacrificial method
2025 - CHIBA, R.; CARVALHO, F.M.S.; GUEDES-SILVA, C.C.
In this work, a comprehensive study was conducted to examine the impact of ammonium bicarbonate (NH4HCO3) content, a porogenic agent, on the development of the microstructure, compressive strength, and Young’s modulus of the porous silicon nitride ceramics using the sacrificial method. The porous ceramics were obtained by pressureless sintering at 1650 oC and characterized by scanning electron microscopy and X-ray diffraction. The findings demonstrated that all samples developed a microstructure with β-Si3N4 grains, but α-Si3N4 and wollastonite were also identified. Moreover, grains with a high aspect ratio are predominant in the pore inner structure. The pore morphology was changed from spherical to irregular when the highest NH4HCO3 content was used. Under this condition, interconnected pores were also present. The values of compressive strength and Young’s modulus decreased with increasing porogen content. The reduction was more pronounced for the ceramic prepared with the highest NH4HCO3 content.
Effect of graphene-based coating 3D printing process on the remanence and corrosion of sintered NdFeB magnets
2024 - CASINI, JULIO C.; COSTA, ISOLDA; FARIA JUNIOR, RUBENS N. de
This study describes a 3D fused deposition modeling (FDM) printing process using a graphene-impregnated polylactic acid (G-PLA) filament to create a new type of rigid, plastic, nonconductive, and anticorrosion layer. Therefore, the possibility of 3D printing a plastic layer using FDM methods is demonstrated herein. A commercial magnet such as N35 NdFeB can be used to produce an efficient shielding film by additive manufacturing. As the coating layer thickness increases, the remanence decreases from 1.17 to 1.01 T for the G-PLA coating. Visual tests were performed after exposure to all aqueous NaCl test solutions (0.5 and 1 M), and no evidence of corrosion of the coating was obtained.
Among land snail shells and ashes
2025 - BATALLA, NICOLÁS; OKUMURA, MERCEDES; MUNITA, CASIMIRO S.; CHARLES, FRENCH; ARAUJO, ASTOLFO G.M.
Geoarchaeological studies, particularly those incorporating micromorphology and associated techniques, have revealed the complex depositional and post‐depositional history of mollusk shell‐matrix archaeological sites, mostly in coastal areas where these sites are more widespread. But geoarchaeology can also be crucial to disentangle human and natural agencies in inland shell‐rich settings, including caves and rock‐shelters. In this paper, the site formation processes of the land snail‐rich Maximiano Rockshelter, located in the karstic upper Ribeira de Iguape River valley of southern São Paulo state, Southeast of Brazil, are tackled. Embedded in the neotropical Atlantic Forest, the site contains lithics, bone artifacts, and faunal and human remains dating between ~11,165 and 1282 cal year B.P. Facies and microfacies were characterized in exposed stratigraphic profiles through micromorphology, particle size analysis, major, minor, and trace elements, and FTIR spectroscopy. Despite the strong humification affecting most of the site, results indicate deposits resulting from anthropic activities such as the dumping of land snail shells and other remains, the tossing of entire and fragmented shells in sub‐ horizontally distributed layers, primary combustion features, and dumping/sweeping of combustion‐derived materials. Shell‐bearing facies exhibit similarities with chronologically contemporaneous Ribeira de Iguape basin's riverine sambaquis.
Recent results on the analysis of the 48Ti(18O, 17O)49Ti reaction at 275 MeV
2024 - SGOUROS, O.; CAPPUZZELLO, F.; CAVALLARO, M.; CARBONE, D.; AGODI, C.; BRISCHETTO, G.A.; CALVO, D.; CHAVEZ LOMELI, E.R.; CIRALDO, I.; CUTULI, M.; DE GREGORIO, G.; DELAUNAY, F.; DJAPO, H.; EKE, C.; FINOCCHIARO, P.; FISICHELLA, M.; GARGANO, A.; GUAZZELLI, M.A.; HACISALIHOGLU, A.; LINARES, R.; LUBIAN, J.; MEDINA, N.H.; MORALLES, M.; OLIVEIRA, J.R.B.; PAKOU, A.; PANDOLA, L.; SOUKERAS, V.; SOULIOTIS, G.; SPATAFORA, A.; TORRESI, D.; YILDIRIM, A.; ZAGATTO, V.A.B.
The study of the one-neutron transfer reaction in the 18O+48Ti collision at the energy of 275 MeV was performed as part of the multi-channel approach which is performed within the NUMEN project. That is to measure the complete reaction network characterized by the same initial and final state interactions as the more suppressed double charge exchange reactions. In this respect, angular distribution measurements for one- and two-nucleon transfer reactions in the 18O+48Ti collision were performed at the MAGNEX facility of INFN-LNS in Catania. This contribution summarizes the main findings from the analysis of the one-neutron transfer reaction.
Pressure vessels structural integrity assessment using failure analysis diagrams
2025 - ROCHA PINTO, J.J.; MATTAR NETO, M.
There is much discussion today about the possibility of extending the lifetime of industrial plant components due to economic factors. Pressure vessels are among the most expensive components, and their replacement can significantly impact the operation of an entire plant. In this context, several Fitness-for-Service (FFS) methodologies can be applied to assess structural integrity, addressing not only economic aspects but also enhancing safety. Failure Assessment Diagrams (FADs) are widely used in FFS methodologies to prevent future failures by analyzing crack-type defects. These diagrams establish acceptability criteria based on the material toughness ratio and loading ratio. Recommended practices utilizing the BS-7910, API-579, and R6 methodologies are addressed in this work, alongside principles from fracture mechanics, material properties, and solid mechanics. The main objective was to develop computer programs in Matlab to analyze a case study involving a pressure vessel manufactured from SA-516 Gr 70 steel, determining the critical dimensions of semi-elliptical cracks in longitudinal and circumferential orientations of a cylindrical section. Level 2 evaluation, the most commonly used in FFS methodologies, was applied to develop the programs. This study enabled the creation of tools to automate calculations and generate FAD graphs, considering the critical depth and length of cracks. These tools support decision-making in structural design requirements and provide a means of evaluating equipment in service with crack-type defects, extending its operational lifetime. The FFS methodologies studied are based on ASME Codes for pressure vessels and piping, particularly Sections III and XI. Based on the analysis of API-579, BS-7910, and R6 methodologies under the operating conditions of the case study, it is possible to conclude that, for normal evaluations, critical length (2c) = 40.64 mm and critical depth (a) = 10.16 mm are acceptable values. However, for evaluations requiring safety considerations under the R6 procedure, applicable to Class A service equipment in the nuclear sector, only critical length (l) = 5 mm and depth (a) = 2.5 mm are permissible values.
Development of a sample exchange system for irradiations in the BH-3 channel of the IEA-R1 reactor at IPEN
2024 - PAULA, M.L. de; MORALLES, M.; GENEZINI, F.A.; SIQUEIRA, P.T.D.; RIBEIRO JUNIOR, I.S.; SILVA JUNIOR, I.A. da
This work was developed with the aim of improving the current sample exchange system of the BH-3 irradiation channel of the IEA-R1 reactor at IPEN. The instrument's operating concept will provide a better use of the irradiation space as well as greater safety and confidence to the operator. The development of the system involved 3D modeling, sizing, construction and non-destructive testing of the various parts, and analysis of neutron-induced activation of the materials most exposed to the beam. A programmable logic controller (PLC) was implemented for the system’s control inside a dedicated electrical panel that was built with materials compatible with the location. The system was designed to support samples weighing up to 15 kg. Bench tests were carried out and showed that the system performs the necessary functions to accurately position samples in three locations: outside the biological shield, at the irradiation channel and at the decay waiting station. The implementation of this instrument will contribute to the application of the ALARA principle in the operator activities at the BH-3 irradiation channel.
Study on the licensing framework for land facilities supporting nuclearpowered submarines in the United Kingdom
2024 - BARONI, D.B.; BORSOI, S.S.; SOARES, Y.S.A.; MATTAR NETO, M.; OLIVEIRA, P.S.P.; MATURANA, M.C.
This study examines nuclear regulation in the United Kingdom, focusing on licensing processes for land facilities supporting nuclear-powered submarines. It highlights the importance of these submarines for defense and maritime security, along with the need for specialized infrastructure to operate them safely and effectively. The study analyzes the UK’s procedures and regulations for nuclear licensing, with emphasis on regulatory bodies such as the Office for Nuclear Regulation (ONR) and the Defence Nuclear Safety Regulator (DNSR). Results discuss the classification of nuclear facilities in the UK, including those dedicated to submarines and nuclear defense, as well as the applicable standards and guidelines for licensing these facilities. It is concluded that nuclear regulation in the UK is robust and transparent, providing a solid foundation for licensing facilities supporting nuclear-powered submarines. The adoption of these standards as a reference in Brazil could significantly contribute to establishing a solid and secure regulatory framework for such facilities.
Impact of distinct sintering temperatures in pellets to strontium immobilization
2024 - SANCHES, G.O.P.; ARAUJO, M.S.; MELLO-CASTANHO, S.R.
The immobilization of radioactive strontium (Sr) from liquid effluents, a byproduct of nuclear fission and accidents, presents significant environmental and public health challenges. This study evaluates the immobilization of Sr in a glass matrix by comparing the effects of different sintering temperatures. The analyses started from three temperatures 800ºC, 900ºC and 1000ºC for each of the four compositions, which vary the addition of niobium (Nb) content in the vitreous matrix by 2%, 4%, 6% and 8% in mol. The highest temperature was excluded because its deformation did not match the final objective, at 900ºC the compositions had better results in density and water absorption, so that at the same temperature the composition with 4% niobium responded better to the results. The study underscores the significance of treating temperature and Nb content in the glass matrix for effective Sr immobilization, offering valuable insights for the development of safe and sustainable nuclear waste management strategies.

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