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  • IPEN-DOC 27631

    COSTA, ROBSON S. ; ARAUJO, DANIELLE G.; ANDRADE, MARCIO S. de; OLIVEIRA, RENE R. ; RANGARI, VIJAYA; MOURA, ESPERIDIANA A.B. ; DIAS, FRANCISCO V.. Production and characterization of PBAT reinforced with clay and graphene oxide nanosheets: a comparative study. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 689-699, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_68

    Abstract: The poly (butylene adipate-co-terephthalate) (PBAT), a biodegradable polymer, is among the most promising materials to be considered as environmentally friendly high performance biodegradable plastics. However, the mechanical properties of PBAT are not the best for several applications. According to the literature, the properties of the biodegradable polymer can be improved by addition of a small amount of nanofillers, such as clay, silica, and graphene. The objective of this study is to compare the effect of the addition of Cloisite clay and graphene oxide (GO) on the properties of flexible films based on PBAT matrix. The composite films based on PBAT with addition of Cloisite (2.0 wt%) and PBAT composite films with addition of Cloisite and GO (0.1–0.2 wt%) were prepared by extrusion, using a twin-screw extruder and a flat die single extruder. The effects of the addition of Cloisite clay and graphene oxide on mechanical and thermal properties of films were evaluated by mechanical and water absorption tests, FE-SEM, XRD, and Raman analysis.


  • IPEN-DOC 27630

    OLIANI, WASHINGTON L. ; KOMATSU, LUIZ G.H. ; LUGAO, ADEMAR B. ; RANGARI, VIJAYA K.; PARRA, DUCLERC F. . Processing and characterization of polyethylene-AgNPs films: biocide effect. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 679-688, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_67

    Abstract: Low-density-polyethylene (LDPE) and Linear-low-density-polyethylene (LLDPE) nanocomposites films containing silver nitrate (AgNO3) and surfactant oleic acid (AO) were manufactured via extrusion and subsequently characterised. The films were evaluated by scanning electronmicroscopy (SEM), energy dispersive spectroscopy (EDX), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and infrared spectroscopy (FTIR). Further, the antibacterial properties of the films were investigated against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) bacteria.The results indicated that LDPE nanocomposite films containing AgNPs have the potential to be used in antimicrobial packaging for food applications.


  • IPEN-DOC 27629

    TAMURA, CAROLINE S.; ARANTES, MARIANA ; CARMO, KARINA H.S. ; SANTOS, BIANCA S. ; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Mechanical and morphological properties of hybrid composites based on recycled LDPE/EVA blend reinforced with clay and babassu fiber residues. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 661-669, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_65

    Abstract: Over the years the consumption of plastic products made of conventional polymers has produced a large amount of waste which has led to disposal problems worldwide. Among the alternatives to minimize these problems are reuse and recycling practices. Then, the recycling of plastic and the use of recycled materials to produce new materials reinforced with nanoparticles from natural resources can be an alternative to reduce inappropriate waste disposal. The objective of this study is to investigate the effects of the addition of clay and non-treated babassu fiber residues on the mechanical and morphological properties of composite based on recycled LDPE/EVA blend. Composite materials containing 1–3 wt% of babassu residues and 1 wt% of clay were prepared using a twin-screw extruder machine and flat die single extrusion process, in order to prepare hybrid composites sheets. The sheets prepared by recycled LDPE/EVA blend and its composites were characterized by tensile tests, XRD, and FE-SEM analysis and the correlation between properties was discussed.


  • IPEN-DOC 27628

    BARTOLOMEI, MARCIO R.X.; CARMO, KARINA H.S. ; SANTOS, BIANCA S. ; BARTOLOMEI, SUELLEN S. ; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Investigation on mechanical and thermal behaviours of PBAT/PLA blend reinforced with reduced graphene oxide nanosheets. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 631-639, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_62

    Abstract: The aim of this study was to process and investigate the changes in the mechanical and morphological properties of the biodegradable nanocomposites based on polybutylene adipate-co-terephthalate (PBAT)/poly(lactic acid) (PLA) blend (PBAT/PLA blend) due to the incorporation of reduced graphene oxide (RGO) nanosheets. The biodegradable polymeric nanocomposites were prepared by melting extrusion process using a twin-screw extruder machine. The influence of the RGO nanosheets incorporation on mechanical and thermal properties of PBAT/PLA blend was investigated by tensile Thermogravimetric (TG), X-Ray diffraction (XRD), differential scanning calorimetry (DSC), and tensile test analysis. Results showed that incorporation of the small amount ofRGO(0.1wt.%) ofRGOnanosheets in the blend matrix of PBAT/PLA resulted in an important gain of mechanical properties of the blend. This result indicates that a very small amount of RGO nanosheets addition in the PBAT/PLA can lead to obtaining materials with superior properties suitable for several industrial applications.


  • IPEN-DOC 27627

    BARTOLOMEI, S.S.; MOURA, E.A.B. ; WIEBECK, H.. Inhibition of flame propagation in nanocomposites with expanded polystyrene recycled clay, gypsum, and titanium dioxide. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 609-618, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_60

    Abstract: The large amount of plastic waste found in the environment, landfills, and dumps boost research into the recycling of polymer materials, which could reduce the amount of polymer discarded. In Brazil, the sector that most consumes polymers is the civil construction that could consume recycled polymerswithout concerns with the properties due to applications of low mechanical exigency. However, for applications in this sector, it is necessary that the materials have some resistance to the propagation of flames. This work discusses the flame retardance in nanocomposites with recycled polystyrene matrix and particles of nanoargila, titanium dioxide, and gypsum. The results of the X-ray diffraction (XRD), differential scanning calorimeter (DSC), field emission scanning electronmicroscopy (FE-SEM), and flammability test. The results showed that glycerol, added during recycling, can plasticize recycled expanded polystyrene while maintaining the flame resistance properties of the material with flame retardant. It can also be concluded that some particles may delay the propagation of the flame in the composite.


  • IPEN-DOC 27626

    SANTOS, BIANCA S. ; INACIO, ANDRE L.N.; BARTOLOMEI, SUELLEN S. ; SILVA, TAISE B.S.; CARMO, KARINA L.S.; OLIVEIRA, RENE R. ; MOURA, ESPERIDIANA A.B. . Influence of the reduced graphene oxide incorporation on properties of acrylonitrile butadiene styrene (ABS). In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 599-607, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_59

    Abstract: The purpose of this study was to evaluate the influence of incorporation of the reduced graphene oxide on properties of acrylonitrile butadiene styrene (ABS). The incorporation of 0.5 and 1.5 wt% of RGO into ABS matrix was carried out by melting extrusion process using a twin-screw extruder and injection molding machine. The properties of ABS/RGO nanocomposite samples were investigated by tensile and impact Izod tests, FE-SEM, and XRD analysis. The results showed that the incorporation of small amount of RGO into ABS matrix led to obtaining of polymeric nanocomposite with superior mechanical properties when compared with original properties of ABS matrix.


  • IPEN-DOC 27625

    TATEI, TATIANE Y. ; FONTES, ERIC H. ; MOREIRA, RENAN P. ; DIAS, FRANCISCO V.; OLIVEIRA, RENE R. ; RANGARI, VIJAYA; MOURA, ESPERIDIANA A.B. . Improvement properties of polypropylene by graphene oxide incorporation. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 581-589, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_57

    Abstract: Due to the remarkable properties of graphene oxide (GO) and its possibility of functionalization,GOhas been used in many applications such as nanocomposites. GO nanosheets have been shown to improve the properties of the polypropylene (PP) matrix, for instance, its strength, gas barrier, thermal, and electrical conductivity. As PP has relatively low cost and varied applications, this work aims to study the changes in its thermal, morphological, and mechanical properties, due to the incorporation of GO in the PP matrix. GO was synthesized from graphite by a modified Hummers method. The nanocomposites PP/GO with 0.1, 0.2, and 0.3 wt% of GO in the PP matrix were obtained using a twin-screw extruder and an injection molding machine via a melt blending process. The nanocomposites PP/GO were characterized by FE-SEM and Izod impact test. In addition, the GO nanosheets were also characterized by Raman spectroscopy, ATR-FTIR, FE-SEM, and XRD, therewith correlation between properties was discussed.


  • IPEN-DOC 27624

    MIRANDA, LEILA F. de; BARBOSA, ISABELLA T.F.; MASSON, TEREZINHA J.; MUNHOZ JUNIOR, ANTONIO H.; SILVA, LEONARDO G. de A. e ; GONÇALVES, ALEKSANDRA A.A.. Characterization of hydrogels for release of cosmetic assets containing nanoemulsions of mandellic acid in different concentrations of pseudoboehmite. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 477-489, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_47

    Abstract: Hydrogel is a gel formed by a three-dimensional network of hydrophilic polymers that are used as advanced asset release systems with good biocompatibility. The use of ionizing radiation to obtain hydrogels promotes cross-linking with the concomitant sterilization of the hydrogels. Aiming at the release of the mandelic acid (an active cosmetic), hydrogels were prepared using different concentration of poly(N-vinyl-2-pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar containing nanoparticles of the pseudoboehmite, mandelic acid and Palmarosa and Rosa Mosqueta oils nanoemulsions, submitted to irradiation dose of 25 kGy. Hydrogels containing 7.5 wt% PVP showed better absorption, slip, odor results, and those with 10 wt% PVP were found to be inadequate. Nanoemulsions were characterized by acidity, density and optical microscopy; hydrogels samples were put under isothermal dehydration with air entrainment and dehydration was examined as a function of time. The results showed that the composition of hydrogels is stable, and the increase of the concentration of pseudoboehmite in hydrogels sample containing Palmarosa oil suffers less dehydration and those containing the two oils showed an increase in dehydration. The hydrogels obtained with 7.5 wt% of PVP and 3 wt% of pseudoboehmite, Rosa Mosqueta vegetable oil and mandelic acid are most suitable to be used in cosmetic products.


  • IPEN-DOC 27623

    KOMATSU, LUIZ G.H. ; OLIANI, WASHINGTON L. ; OLIVEIRA, CAMILA B. ; RANGARI, VIJAYA K.; PARRA, DUCLERC F. . Application of nanoparticles of ZnO and ZnO-doped-Ag in polymeric blend of HMSPP/SEBS for biocide activity. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 429-435, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_41

    Abstract: In this study, the nanoparticles of Zinc oxide (ZnO) and Zinc oxide doped with Silver (ZnO/Ag) were synthesized in laboratory. The incorporation of these nanoparticles in the blend of high melt strength polypropylene (HMSPP) and styrene– ethylene/butadiene–styrene (SEBS) was carried by melt processing. The obtained materials were evaluated by X-ray diffraction (XRD), Raman Spectroscopy, Differential Scanning Calorimetry (DSC), biocidal tests against the bacteria Escherichia coli and Staphylococcus aureus. The nanoparticles showed size between 150 and 200 nm and spherical form. HMSPP/SEBS/AgNPs/ZnO films incorporated with the nanoparticles have demonstrated biocidal effect against the bacteria E. coli and S. aureus when irradiated at 12.5 kGy.


  • IPEN-DOC 27622

    SOARES, CARLOS ; SANTANA, JULYANA ; GUVEN, OLGUN; MOURA, ESPERIDIANA A.B. . A comparison between graphene oxide and reduced graphene oxide as reinforcement agents in polypropylene nanocomposite using irradiated polypropylene as compatibilizer. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 385-394, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_36

    Abstract: Graphene is thematerial with the bestmechanical resistance ever encountered. Various types of studies have been carried out on possible applications. The use as a reinforcement in nanocomposites has shown to be a promising field, but some studies indicate that the graphene oxide (GO) and reduced graphene oxide (RGO) have better results as reinforcement, due to the functional groups,which allowa better adhesion with the matrix. This study analyzes the production of polypropylene (PP) nanocomposite comparing the use of graphene oxide (GO) and reduced graphene oxide (RGO) as fillers and irradiated polypropylene as a coupling agent.Atwin-screw extruder and injection molding machine were used to produce the nanocomposite PP reinforced with 0.2 wt% of GO and RGO by melt blending. The GO and RGO were characterized byXRDanalysis.The nanocomposite sampleswere characterized by XRD, SEM, TG, DSC and mechanical test.


  • IPEN-DOC 27621

    COSTA, ROBSON S. ; MOURA, ESPERIDIANA A.B. . A bibliometric analysis of the strategy and performance measurement of the polymer matrix nanomaterials development scenario globally, and the participation of Brazil. In: LI, JIAN (Ed.); ZHANG, MINGMING (Ed.); LI, BOWEN (Ed.); MONTEIRO, SERGIO N. (Ed.); IKHMAYIES, SHADIA (Ed.); KALAY, YUNUS E. (Ed.); HWANG, JIANN-YANG (Ed.); ESCOBEDO-DIAZ, JUAN P. (Ed.); CARPENTER, JOHN S. (Ed.); BROWN, ANDREW D. (Ed.). Characterization of Minerals, Metals, and Materials. Cham, CZ, Switzerland: Springer Nature Switzerland AG, 2020. p. 329-342, (The Minerals, Metals & Materials Series). DOI: 10.1007/978-3-030-36628-5_31

    Abstract: Extensive studies have been conducted worldwide on the strategy for the development of nanomaterials. One of the known strategies for this has aroused interest in the market is the incorporation of the nanoparticles, extracted from the residues in thematrices of the polymers for the production of environmentally correct nanocomposites. This work presents a survey of the scientific knowledge of nanomaterials of the polymer matrix and a panoramic view of the evolution of these nanomaterials are subject, in order to meet the criteria of sustainable development due to the environmental concerns. This study also intends to use bibliometric tools to database acquisition and analysis of bibliographic reviews for an evaluation of the scenarios in the world on the development of polymeric nanomaterials based on three different classes of polymeric nanocomposites: polymer/clay; polymer/graphene, and polymer/nanocellulose nanocomposites.


  • IPEN-DOC 27620

    ABE, ALFREDO ; SILVA, ANTONIO T. e ; GIOVEDI, CLAUDIA; MELO, CAIO; GOMES, DANIEL de S. ; MUNIZ, RAFAEL R.. The IPEN/CNEN contribution to IAEA FUMAC benchmark using modified fuel performance code based on stainless steel as cladding under steady state, transient and accident conditions. In: TECHNICAL MEETING ON MODELLING OF FUEL BEHAVIOUR IN DESIGN BASIS ACCIDENTS AND DESIGN EXTENSION CONDITIONS, May 13-16, 2019, Shenzhen, China. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020. p. 1-9.

    Abstract: The IPEN/CNEN (Brazil) participated in IAEA Coordinated Research Project on Fuel Modeling in Accident Conditions (FUMAC) among others 18 countries (Argentina, Belgium, Bulgaria, China, Czech Republic, Finland, France, Germany, Hungary, Italy, Japan, Norway, Republic of Korea , Russian Federation , Spain , Sweden , Ukraine and United States of America), which aim was focused in modelling, predicting and improving the understanding of the behaviour of nuclear fuel under accident conditions in order to better understanding and enhanced safety of nuclear fuel. A serie of LOCA (Loss of Coolant Accident) experiments data were made available for the participants to perform simulation using their fuel performance codes and the outcome gives an idea about fuel codes limitation considering LOCA simulation and possible improvement needed in the existing models related to LOCA condition.The IPEN/CNEN (BRAZIL) proposal for FUMAC-CRP was to modify existing fuel performance codes (FRAPCON and FRAPTRAN) considering stainless steel as cladding material and perform a simulation comparing to zircaloy cladding performance under steady state and accident condition. The HALDEN LOCA Experiments (IFA 650-9, IFA-650-10 and IFA-650-11) were selected and modeled to perform the LOCA accident simulation considering the original cladding (zircaloy) and compared to stainless steel cladding.


  • IPEN-DOC 27619


    Abstract: The Amazon is at the center of an intensifying conversation about multiple anthropogenic impacts, both direct (e.g. land use change) and indirect (climate and hydrologic change). Thus far, research has focused primarily on the cycling and storage of carbon (C) and its implications for global climate. Missing is a holistic consideration of the interactions between these anthropogenic impacts and the full suite of climate forcing agents originating in the basin, including other greenhouse gases (methane, nitrous oxide), biogenic volatile organic compounds (BVOCs), black C, transpiration and albedo. Doing so is complicated by the very large variation in biophysical, ecological, cultural and political factors across the large area of the basin. Here, we synthesize the current understanding of 1) the nature, extent, rates and drivers of all major anthropogenic changes, and 2) their expected magnitude and direction of effect on each major climate forcing agent. Studied anthropogenic impacts span a range of scales and include deforestation, agricultural conversion, hydrologic and climatic regime change, reservoir construction, fire, mining/oil extraction, hunting, severe storms and others. We identify key knowledge gaps and identify likely impacts on the net climate forcing effect of the region. We conclude that the current net positive radiative forcing of non-CO2 agents in the Amazon (in particular methane, nitrous oxide and black C) is likely be equal to or greater than the more often considered CO2 climate impact. If unchecked, the majority of anthropogenic change agents are likely to further increase net radiative forcing from the region, both by reducing C uptake and increasing emission of other agents. Most significant rate and response uncertainties are associated with 1) methane production in seasonally inundated areas and effects of temperature/hydrologic change 2) patterns and radiative forcing impacts of BVOCs, 3) impacts of spatially/temporally variable phenomena such as severe storms and 4) biogeochemical and ecological resiliency of freshwater systems. Given the large contribution of these less-recognized forcing agents, a continuing focus on a single metric of climate service is incompatible with understanding and managing the biogeochemistry of climate in a rapidly changing Amazon.


  • IPEN-DOC 27618

    BASSO, LUANA S.; GATTI, LUCIANA V.; MARANI, LUCIANO; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; CORREA, SERGIO M.; MILLER, JOHN B.; GLOOR, MANUEL; DOMINGUES, LUCAS G.; ARAI, EGIDIO; SANCHEZ, ALBER; ARAGÃO, LUIZ E.O.C.; CORREIA, CAIO S. de C. ; NEVES, RAIANE A.L.; CRISPIM, STEPHANE P.. First Amazon Methane budget based in atmospheric long term data provided by aircraft vertical profiles measurements. In: AGU FALL MEETING, December 1-17, 2020, Online. Abstract... Washington, DC, USA: American Geophysical Union, 2020.

    Abstract: The overall Methane (CH4) budget remains highly uncertain even with the efforts to improve the estimates and contributions of its many sources (natural and anthropogenic) and few sinks. Wetland emissions are considered the primary natural CH4 source but with large uncertainty in estimations. Tropical regions like the Amazon, host some of the largest wetlands areas on the globe. However, these regions are still poorly observed with large-scale integrating observations. Here we present the first long term (2010-2018) atmospheric sampling of the lower troposphere over the Amazon using regular vertical profile (300m to 4.4km height) observations of CH4 and carbon monoxide (CO) at four sites. The sampling was nearly biweekly using small aircrafts, to provide solid seasonal and annual CH4 budgets with large spatial resolution. Was calculated a CO/CH4 ratio to estimate CH4 emissions from biomass burning. An increase in emissions mainly during the dry season at all sites from biomass burning was observed. The results show a regional variation in biogenic CH4 emissions (total minus biomass burning emissions). There are comparably high emissions from the Amazon northeast region (SAN) exhibiting strong seasonality, with particularly high CH4 fluxes one month before (February/March) the wet season peak. The second period of high emissions occurs during the beginning of the dry season (August). In the other three sites (ALF, RBA and TAB_TEF) located further downwind along the main air-stream, it were observed lower emissions, which represents approximately 20-33 % of what was observed in the northeast region and with a clear annual seasonality. Besides, we discuss how these data vary throughout the years and how it can be correlated to climate variables (temperature, precipitation and equivalent water thickness) and with human-driven influence (biomass burning), which both could be impacting this variability and annual seasonality.


  • IPEN-DOC 27617

    GATTI, LUCIANA V.; BASSO, LUANA S.; DOMINGUES, LUCAS G.; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; MILLER, JOHN B.; GLOOR, EMANUEL U.; ARAGÃO, LUIZ E.O.C.; NOBRE, CARLOS; PETERS, WOUTER; ANDERSON, LIANA O.; VON RANDOW, CELSO; ARAI, EGIDIO; MARANI, LUCIANO; SANCHEZ, ALBER; CORREA, SERGIO M.; CORREIA, CAIO S. de C. ; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.. Amazon plays an important climatic role and deforestation is promoting important changes and a consequent increase in the carbon balance. In: AGU FALL MEETING, December 1-17, 2020, Online. Abstract... Washington, DC, USA: American Geophysical Union, 2020.

    Abstract: We present a nine-year study designed to present both regional and temporal representation of Amazon Carbon Balance from 2010 to 2018 using 590 aircraft vertical profiles. Four locations were strategically chosen: the northeast (SAN), southeast (ALF), northwest (TAB_TEF), and southwest (RBA) regions. Each of these regions represents a different deforestation scenario, land-use change, and climate impact. For instance, 37% of the region of influence at SAN site has already deforested; it also has shown the greatest changes in precipitation and Carbon emission. The changes in precipitation (P) and temperature (T) are mainly in the dry season for all sites. At the ALF site, 28% deforested, showed the greatest changes in temperature, and the second-highest carbon emission. On the other hand, the western Amazon sites (RBA and TAB_TEF), accounted for an average of deforestation of 16%, presented near neutral carbon balance and lower changes in precipitation and temperature. The eastern Amazon (SAN + ALF) represented 22% of the Amazon area, presented 27% of deforestation and was the region where dry season presented more substantial changes in precipitation (reduced by 24-34%) and temperature (increased by 1.9-2.5 ˚C). As a consequence of these climatic and anthropic changes, the carbon flux emission at eastern Amazon was around ten times higher than at western Amazon (RBA + TAB_TEF). Eastern Amazon was a carbon source during the 9-year analysis, of which 89% of the carbon flux comes from biomass burning. In the western Amazon, the low deforestation (~11%) showed less changes in dry season P and T and carbon sink in the Net Biome Exchange (NBE C Flux: Total C Flux less Fire C Flux). If the whole Amazon had the western NBE C flux, it could be removed from the atmosphere 0.74 Gt CO2 y-1. Therefore, Amazon is becoming a carbon source mainly due the fire emissions, which represent two times the Amazon carbon sink, as a result of anthropic and climatic changes.


  • IPEN-DOC 27616

    PERROTTA, J.A. ; CARVALHO, E.F.U. ; DURAZZO, M. ; SANTOS, L.R. dos ; BAPTISTA, J.A. ; SILVA, J.E.R. da ; JUNQUEIRA, F.C. ; SANTOS, ADIMIR dos ; ARAUJO, A.M.V. de; TOMAZELLI, I.. The RMB project: fuel cycle management. In: INTERNATIONAL CONFERENCE ON RESEARCH REACTORS: ADDRESSING CHALLENGES AND OPPORTUNITIES TO ENSURE EFFECTIVENESS AND SUSTAINABILITY, November 25-29, 2019, Buenos Aires, Argentina. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020.

    Abstract: The Brazilian Nuclear Energy Commission (CNEN) decided to construct a new research reactor, named RMB (Brazilian Multipurpose Reactor). It is a 30 MW open pool-type research reactor using low enriched uranium fuel, and several associated facilities and laboratories. To establish an infrastructure for producing fuel assemblies for RMB operation and uranium targets for Mo-99 production, the RMB technical secretary has developed a coordinated project for the fuel cycle management system, putting together the fuel technology actors in Brazil. The goals of this coordinated project were: (i) to have a centrifuge cascade enriching uranium up to 20 wt% with the capacity to supply RMB yearly needs; (ii) to upgraded the CNEN existing infrastructure to produce nuclear fuel assemblies and uranium targets for the RMB yearly needs; (iii) to produce a set of fuel assemblies for a real RMB mockup core at the IPEN/MB-01 Critical Facility of CNEN. The RMB project design incorporates structures, systems and components (SSC) for interim storage of spent fuels for the hole plant lifetime. This paper presents details of the coordinated project that gives support and sustainability to the RMB fuel cycle supply and the spent fuel SSC designed.


  • IPEN-DOC 27615

    PERROTTA, J.A. ; SOARES, A.J. ; LIM, M.L.; IBELLI, M.C.; BARRERA, M.; KOROCHINSKY, S.; GAMBETTA, M.. The RMB project: technical and management development status. In: INTERNATIONAL CONFERENCE ON RESEARCH REACTORS: ADDRESSING CHALLENGES AND OPPORTUNITIES TO ENSURE EFFECTIVENESS AND SUSTAINABILITY, November 25-29, 2019, Buenos Aires, Argentina. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020.

    Abstract: The Brazilian Nuclear Energy Commission (CNEN) decided to construct a new research reactor, named RMB (Brazilian Multipurpose Reactor). This reactor will be part of a new nuclear research center, to be built on a site about 100 kilometers from São Paulo city, in the southeast part of Brazil. It is a 30 MW open pool-type research reactor using low enriched uranium fuel, and several associated facilities and laboratories in order to produce radioisotopes for medical and industrial use; to use thermal and cold neutron beams in scientific and technological research; to perform neutron activation analysis; and to perform materials and fuel irradiation tests. This project started in September 2008 and is nowadays at the development stage before construction. This article presents updated information on the technical design and the safety features regarding the reactor and the overall installation. It also presents an update on the nowadays overall development status of the RMB project and lessons learned related to the complexity of the project management.


  • IPEN-DOC 27614

    BITELLI, U.D. ; COELHO, P.R.P. ; FERREIRA, P.S.B. ; ALVES, M.A.P.; SILVA, A.A. ; SANTOS, A. ; DINIZ, R. ; JEREZ, R. ; FUGA, R. ; FANARO, L.C.C.B. ; KURAMOTO, R. ; ABE, A. ; LAMBIASI, B.; GIADA, M.; FER, N.; MARTINS, F. ; MURA, L. ; SANTOS, D.F. ; AREDES, V. ; MAEDA, R.; GONNELI, E. ; SILVA, A.F.P.; PURGATO, R. ; GONÇALVES, L.B. ; SILVA, G.S.A. ; PINTO, L. ; SOUZA, G.. Main experiments performed at the IPEN/MB-01 RR using UO2 fuel rods core. In: INTERNATIONAL CONFERENCE ON RESEARCH REACTORS: ADDRESSING CHALLENGES AND OPPORTUNITIES TO ENSURE EFFECTIVENESS AND SUSTAINABILITY, November 25-29, 2019, Buenos Aires, Argentina. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020.

    Abstract: This paper aims to show the main experimental utilization of the IPEN/MB-01 zero power reactor during the last 30 years with 3663 operations cycles. The IPEN/MB-01 reactor it was mainly used to validation of calculation methodology used in nuclear reactor cores design.


  • IPEN-DOC 27613

    PERROTTA, J.A. . Considerations and challenges of research reactor management. In: INTERNATIONAL CONFERENCE ON RESEARCH REACTORS: ADDRESSING CHALLENGES AND OPPORTUNITIES TO ENSURE EFFECTIVENESS AND SUSTAINABILITY, November 25-29, 2019, Buenos Aires, Argentina. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020.

    Abstract: Technically, nuclear reactors are equipment were neutron chain reactions of fissile material are safely controlled. Particularly, Research Reactors (RR) use the produced neutrons to a variety of objectives in science, technology, innovation, education, and direct products to society as, for example, the radioisotopes for nuclear medicine. Management is a fundamental aspect to the mission success of a RR and essential to its sustainability and effectiveness. As higher the neutron flux and the RR utilization, more complex are the management actions required to the installation, and their out-installation interfaces as well. Nevertheless, basic management requirements are still necessary to low neutron flux RR, for example, a critical facility. There are many important areas to be considered in RR management as organizational structure, operation, utilization, safety, fuel management, waste management, accessibility and security, human resources development, and financial resources among others. This paper resumes the author invited oral presentation that covers relevant aspects of RR management. Examples are given, based on the author’s experience, related to RRs fulfilling their planned missions and, particularly, related to the development and installation of a new RR project.


  • IPEN-DOC 27612

    GENEZINI, F.A. ; FERNANDES, A.J.; ZAHN, G.S. . The IEA-R1 62 years of operation: experiences and lessons learned. In: INTERNATIONAL CONFERENCE ON RESEARCH REACTORS: ADDRESSING CHALLENGES AND OPPORTUNITIES TO ENSURE EFFECTIVENESS AND SUSTAINABILITY, November 25-29, 2019, Buenos Aires, Argentina. Proceedings... Vienna, Austria: International Atomic Energy Agency, 2020.

    Abstract: Early in 1956, the Atomic Energy Institute (IEA, from the acronym in portuguese) was founded with the aim of installing the nuclear research reactor purchased from the American company Babcock & Wilcox in the framework of the “Atoms for Peace” program. The start-up was on September 16, 1957, where the first criticality in the Southern hemisphere was achieved. The IEA-R1 is a pool type, light water cooled and moderated, beryllium and graphite reflected research reactor. Although designed to operate continuously at up to 5 MW, it operated at 2 MW for 40 years and only rather recently started operating at 5 MW. This year IEA-R1 completed 62 years of operation. The reactor is the core of the Nuclear and Energy Research Institute – IPEN (former IEA) – with its laboratories working for radiopharmaceutical applications, in the areas of radiological protection, nuclear fuel cycle, nuclear engineering, and radiation applications among others. Throughout this period it underwent several reforms, renovations and changes of management. In 2000 an Integrated Management System (IMS) has been structured, based on ISO-9001, in order to keep the operation safe, which implied certain procedures together with a continuous modernization program, and to comply with the regulatory requirements at the date as well. The first certification dates to 2002 and since then the reactor has been successfully renewing its ISO certification. The history, experiences and lessons learned during the 62 years of the IEA-R1 operation are described and shared in this paper.


  • IPEN-DOC 27611

    DINIZ, RAPHAEL E. ; OLIVEIRA, ALDO R. de ; TERRA, ADRIANA C. ; POTIENS, MARIA da P.A. . Avaliação do desempenho do sistema de referência para a calibração de medidores de radiação. In: CONGRESSO DE QUALIDADE EM METROLOGIA, LABORATÓRIOS E INDÚSTRIA, 17., 30 de novembro - 2 de dezembro, 2020, Online. Anais... São Paulo, SP: Rede Metrológica do Estado de São Paulo, 2020. p. 1-7.

    Abstract: O Laboratório de Calibração do Instituto de Pesquisas Energéticas e Nucleares, LCI, atua a mais de 30 anos calibrando instrumentos medidores de radiação aplicados em procedimentos de proteção radiológica, radioterapia e radiodiagnóstico, pertencentes a hospitais, indústrias, clínicas e outros usuários. No ano de 2002, foi estabelecido um Sistema da Qualidade no LCI que desde então tem passado por auditorias internas anualmente. No ano de 2017 o laboratório conseguiu alcançar a acreditação de acordo com a norma ISO 17025 para o escopo “calibração de instrumentos de medição em proteção radiológica: medidor de taxa e de equivalente de dose ambiente”. O sistema utilizado como referência para estas calibrações é composto por uma câmara de ionização esférica marca PTW, com volume de 1L, acoplada a um eletrômetro PTW, modelo UNIDOS. Este sistema tem passado por calibrações periódicas com rastreabilidade ao Laboratório Nacional de Metrologia das Radiações Ionizantes. Para garantir um bom desempenho nas medicões realizadas com este sistema, foi implantado um programa de controle de qualidade com testes de repetibilidade, corrente de fuga e estabilidade ao longo do tempo. Foi utilizada uma fonte de controle de Sr-90 também da PTW. Neste trabalho é demonstrado o desempenho dos sistema de referência ao longo de 18 anos. Foram realizados em torno de 100 testes de controle de qualidade. Os resultados obtidos foram comparados com o gráfico histórico de estabilidade do sistema. É permitida uma variação de até 2% do valor de referência determinado anteriormente.


  • IPEN-DOC 27610

    SARAU, SARA T.; RODRIGUES JUNIOR, ORLANDO ; POTIENS, MARIA da P.A. . Instrução Normativa n° 54 da ANVISA e a importância dos testes de aceitação e controle de qualidade em serviços mamográficos. In: CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇÕES IONIZANTES, 7., 23-25 de novembro, 2020, Online. Anais... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2020. p. 1-12.

    Abstract: Considerando que em 26 de dezembro de 2019 a ANVISA publicou a RDC n° 330 para serviços de radiologia diagnóstica e intervencionista e a Instrução Normativa n° 54 para sistemas de mamografia, neste trabalho realizou-se uma análise do estabelecido para testes de dosimetria da mama e de camada semi-redutora e um estudo comparativo de valores obtidos em quatro mamógrafos digitais direto publicados na literatura e os valores de referência e de tolerância apresentados na IN-54. Os resultados reforçam a importância da elaboração de um programa de controle de qualidade e da análise conjunta dos resultados obtidos em todos os testes.


  • IPEN-DOC 27609

    XAVIER FILHO, JOEL M.; SILVEIRA, IURY S.; CALDAS, LINDA V.E. . Espectros de feixes padrões de radiação X nas qualidades de radiodiagnóstico e mamografia a partir de simulações Monte Carlo. In: CONGRESSO BRASILEIRO DE METROLOGIA DAS RADIAÇÕES IONIZANTES, 7., 23-25 de novembro, 2020, Online. Anais... Rio de Janeiro, RJ: Sociedade Brasileira de Metrologia, 2020. p. 1-9.

    Abstract: Foram simulados os seis feixes RQR 5, 8, M1, M2, M3 e M4 descritos na norma TRS-457 (IAEA) utilizando o código de Monte Carlo EGSnrc. Foram realizadas simulações computacionais de um tubo de raios X para a obtenção de seus espectros utilizando o software BEAMnrc. As curvas de atenuação para cada espectro foram obtidas com o aplicativo egs_kerma. Por meio das 1ª e 2ª camadas semi-redutoras, dos coeficientes de homogeneidade e das energias médias foi possível determinar a qualidade de cada um dos feixes simulados. Todos os parâmetros de qualidade foram próximos aos estabelecidos na norma TRS-457 (IAEA).


  • IPEN-DOC 27608

    ZAHN, GUILHERME S. ; GENEZINI, FREDERICO A. ; MORALLES, MAURICIO ; SOUZA, FRANCISCO A. . Playing with neutrons: experimental facilities at the IEA-R1 reactor. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: Due to their unique characteristics, neutrons are an excellent tool to probe materials, as well as to produce radionuclides for other uses. The IEA-R1, the largest nuclear research reactor in Brasil, located in IPEN-CNEN/SP, is a 5MW pool-type reactor from the mid-1950's that, despite its age, still provides important facilities for neutron irradiation and probing under high neutron uxes. These facilities can be divided in two groups: in-core irradiation positions with uxes ranging from 10(12) to 10(14)cm(-2).s(-1), where a sample is irradiated inside the reactor core for posterior analysis; and in-beam facilities, with 8 radial and 2 tangential tubes delivering collimated neutrons in the experimental hall with uxes up to 10(8)cm(-2).s(-1), where a sample is irradiated outide the core, under a considerably lower ux, but with the possibility of real-time analysis and of better radiation filtering and collimation. Different experiments can be performed using the IEA-R1 neutron sources, and this work intends to showcase these facilities, giving an insight regarding the specific properties or each, with their capabilities and some present applications, while also discussing some possible future applications.


  • IPEN-DOC 27607

    SERRA FILHO, L.A.; BREGANT, M.; MUNHOZ, M.G.; SOUZA, F.A. ; MORALLES, M. . Position sensitive GEM-based neutron detector prototype. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: In response to the 3He shortage [1], alternatives for thermal neutron detection are being pursued nowadays. Elements such as 157Gd, 10B and 6Li are commonly used to substitute 3He due to their high neutron capture cross section. In this work, we present our thermal neutron detector prototype, which makes use of 10B as converter. This detector works under Ar/CO2 (90/10) open flux and uses two gas electron multipliers (GEMs) [2] microstructures to multiply the charge signal. The neutrons are detected through the gas ionization generated by the products of the 10B(n; a)7Li reaction. The neutron capture takes place in the inside face of the aluminum cathode, which is coated with a 2:2 μm thick 10B4C layer (deposition kindly provided by the European Spallation Source (ESS) laboratories). Experimental measurements obtained in the IEA-R1 nuclear research reactor, at the Nuclear and Energy Research Institute (IPEN), shown that our prototype presents high stability, position sensitivity with spatial resolution better than 3mm and an efficiency of 2.97(25)%, allowing its application as beam profiler. Methods to increase the neutron detection efficiency will then be discussed.


  • IPEN-DOC 27606

    SANTOS, R.F.; MUNHOZ, M.G.; MORALLES, M. . Performance and optimization simulations of a GEM-based neutron detector. In: REUNIÃO DE TRABALHO SOBRE FÍSICA NUCLEAR NO BRASIL, 43., 14-16 de dezembro, 2020, Online. Resumo... São Paulo, SP: Sociedade Brasileira de Física, 2020.

    Abstract: In this study, we are investigating the performance and optimization of a GEM-based detector to measure thermal neutrons from a nuclear reactor by means of computer simulation, using Geant4 and Garfield++. Due to the shortage of helium isotope, widely used in neutron gaseous detectors, alternatives need to be studied to continue producing this kind of detectors. The GEM detectors are a type of Micro-Pattern Gaseous Detectors (MPGD), widely used in particle tracking systems, as the Time Projection Chamber of the ALICE experiment in the LHC-CERN, and proposed for many other applications, including neutron detection. The detection of neutrons occurs through a nuclear reaction, where the products are energetic charged particles. In our application, we are using 10B as a neutron converter to induce the nuclear reaction 10B(n; )7Li. Monte Carlo simulations play an important step in the development and optimization of this kind of detectors. We are using a combination of simulation tools. At first, Geant4 is used to calculate the interaction between neutrons and the boron converter layer, as well as the transport of its products inside the converter. Then the interaction of the reaction products with the gas volume, leading to ionization or excitation of atoms, is done in Garfield++. This allows us to study the GEM in various conditions and with a detailed description of electron avalanche through the gas and its induced signals in order to achieve a tool to obtain optimized detector configurations for different applications, as beam monitors.


  • IPEN-DOC 27605


    Abstract: The NUMEN (NUclear Matrix Elements for Neutrinoless double beta decay) project was recently proposed [1], with the aim to investigate the nuclear response to Double Charge Exchange (DCE) reactions for all the isotopes explored by present and future studies of 0νββ decay. The expected level of radiation in the NUMEN experiment imposes severe limitations on the average lifetime of the electronic devices. During the experiments it is expected that the electronic devices are exposed to about 105 neutrons/cm2/s according to FLUKA simulations. This work investigates the reliability of the System On Module (SOM) by National Instruments (NI) under neutron radiation [2]. The tests were performed using thermal, epithermal, and fast neutrons produced by the Instituto de Pesquisas Energéticas e Nucleares (IPEN) 4.5 MW Nuclear Research Reactor. The results show the NI-SOM is robust to neutron radiation for the proposed applications in the NUMEN project.


  • IPEN-DOC 27604

    PARRA, DUCLERC F. ; SANTOS, VINICIUS J. dos ; TAMIÃO, ANGELICA . Development of poly (n-vinyl-2-pyrrolidone) hydrogels containing nanosilver and laponite clay for modulation of neomycin. Journal of Astrophysics & Aerospace Technology, v. 8, n. 2, p. 3-3, 2020.

    Abstract: These Biomaterials widely used in biomedicine as wound dressings are composed by hydrogels. They offer ideal conditions for wound treatment, such as maintaining the wound environment humid, autolytic debridement, accelerated healing, ability to absorb large amounts of fluids without losing their physical integrity, drug release in a controlled manner protecting infected wounds that are constantly exposed to environment contaminated with microorganisms. These dressings are formed by one or more polymeric components which, when cross-linked, form three-dimensional networks. They have a high degree of flexibility that is very similar to natural living tissues. The general objective of this work was to synthesize by radiation hydrogel membranes containing PVP, PEG, agar, RD laponite in a neomycin and nanosilver release system that promotes a synergistic action between these two antimicrobial agents. Membranes with different concentrations of polymer matrix / clay were produced by irradiation at a dose of 25 kGy of gamma 60Co source, and characterized by techniques: swelling analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), tensile tests, parallel plate rheometry. It can be seen that G 'and G "are approximately parallel within the studied range. G 'is greater than G' 'and both showed little frequency dependence. This performance is the expected for the gels, in which the elastic behavior of the sample predominates over its viscous behavior. The clay-polymer interactions increases gel cross-linking, which provides an increase in their mechanical properties. In parallel, nanoparticles of silver coupled to clay (Laponite) were synthesized in which their properties were verified by means of UV-Vis, MET, ICP-OES and microbiological activity. The study of the microbiological activity of AgNPs-Laponite nanoparticles on the reduction of microorganisms in culture indicated that most of the nanoparticles, synthesized from the reduction of silver ions on the surface of Laponite, have activity against Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, Candida albicans.


  • IPEN-DOC 27603

    SOARES, E.P. ; FILHO, J.C.S. ; CASINI, J.C.S.; FARIA, R.N. ; TAKIISHI, H. . The influence of the addition of rGO and CNT on the electrochemical properties of the batteries the LaNi-based battery alloys. Materials Science Forum, v. 1012, p. 153-157, 2020. DOI: 10.4028/

    Abstract: In this article the results of the negative electrode performance produced by La0.7Mg0.3Al0.3Mn0.4Co0.5Ni3.8 as-cast alloy adding 1 to 10% of carbon nanotube (CNT) or reduced graphene oxide (rGO) were investigated as Ni-MH batteries. The as cast alloy were investigated with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The CNT and rGO were characterized by high resolution SEM-FEG. The discharge capacity obtained during the electrochemical characterization showed that in the addition of 1% rGO the discharge capacity was 332 mAh and 1% CNT 364 mAh , being that the rGO batteries maintaining better cyclic stability during the electrochemical test.


  • IPEN-DOC 27602

    MEIRA, MARCO A. ; MOISES, LUCAS C.; SILVA, MELISSA R.M. da; JANASI, SUZILENE R.; TAKIISHI, HIDETOSHI. PrFeB based alloys obtained by melt spinning for the production of permanent magnets. Materials Science Forum, v. 1012, p. 314-318, 2020. DOI: 10.4028/

    Abstract: Rare earth permanent magnets are essential components in many fields of technology due to their excellent magnetic properties. There are some techniques used in the manufacture of permanent rare earth magnets: the powder metallurgy to obtain anisotropic HD sintered permanent magnets and the melt spinning and HDDR processes to obtain isotropic and anisotropic bonded permanent magnets. In this work, the influence of the melt spinning parameters on the microstructural and magnetic properties of the Pr14FebalCo16B6 alloy was studied. The alloy was melted and rapidly cooled at 9.9 x 105°C/s. The parameters used in the process were: wheel speed of 15 m/s and 20 m/s and ejection pressure of 25.3 kPa and 50.7 kPa. Ribbons and/or flakes of 30 μm thickness and width until 5 mm were obtained. Results show that the melt spinning alloys are nanocrystalline and that the parameters of the process influence the microstructure and their magnetic properties. Mean crystallite size up to 38.5 nm and intrinsic coercivity (iHc) up to 254 kA/m were obtained.


  • IPEN-DOC 27601

    CANAZZA, MOISES A.; SCAGLIUSI, SANDRA R. ; WIEBECK, HELIO. New applications of tire powder recycled by micro-waves. Materials Science Forum, v. 1012, p. 84-88, 2020. DOI: 10.4028/

    Abstract: In order to minimize impacts caused to environment and to save natural resources, especially from non-renewable sources, recycling of polymeric materials has been object of study. In this scenery, are included elastomeric materials, such as rubber, especially used in tires manufacturing, considering that pneumatic industry consumes around 60% of rubber production. Taking into account that final tires destination is a requirement based on norms and national and international laws, this work aims to the development of a study on the efficacy of micro-wave irradiation in the process of de-vulcanization of tire powder to be used in recycling. Tire powder was subjected to micro-wave irradiation and further merged to SBR (butadiene-styrene rubber) polymeric matrix, at 5, 15, 25 phr; after mixture, resulting compound was characterized for evaluation of physico-chemical and mechanical properties. For the assessment of all samples containing SBR and rubber powder there were applied following essays: Infra-red spectroscopy (FTIR), Tensile strength and elongation at break, Swelling Index. It was verified higher values for mechanical properties imparted by an increased quantity of rubber powder incorporated to SBR matrix.


  • IPEN-DOC 27600

    LEITE, DANIELA M.C. ; ALENCAR, MAICON C. de ; MUCSI, CRISTIANO S. ; ARAUJO, JOAO V.S. ; TAVARES, LUIZ A. ; BERBEL, LARISSA O. ; ARANHA, LUIS C. ; ROSSI, JESUALDO L. . Modifications of titanium and zirconium alloy surfaces for use as dental implants. Materials Science Forum, v. 1012, p. 477-482, 2020. DOI: 10.4028/

    Abstract: The use of dental implants of titanium and its alloys has proved to be effective, through well established and documented parameters, both in the dimensions and in the manufacturing processes and also in the surgical techniques. There are clinical situations where there is a need to reduce the diameter of the implants, below 3.75 mm in diameter. In the current state of art of the implant technology it is desirable that these also have surfaces capable of decreasing the period of osseointegration. In the present work, to improve the mechanical strength of the material, an alloy of 80% of Ti and 20% of Zr % in mass was proposed and elaborated, aiming its use as biomaterial. Physical, chemical, microstructural and mechanical characterization was carried out. The surfaces of the treated samples were observed using: scanning electron microscopy (SEM); semi quantitatively chemically analyzed using dispersive energy spectroscopy (EDS: wettability of the samples was determined and, finally, the roughness was measured using optical profilometry. For the conditions used in the present work, it was concluded, that the best surface treatment for the TiZr 80/20 alloy was acid etching with 1% vol. hydrofluoric acid for 5 minutes, as this treatment presented the most prominent results of wettability and roughness simultaneously.


  • IPEN-DOC 27599

    MICELLI, ANA L.P. ; NIGRO, FREDERICO ; MUCSI, CRISTIANO S. ; ALENCAR, MAICON C. de ; ARANHA, LUIS C. ; ROSSI, JESUALDO L. . Analysis of the pullout testing of straight and angled abutments in narrow diameter implants. Materials Science Forum, v. 1012, p. 461-465, 2020. DOI: 10.4028/

    Abstract: Despite the success of osseointegrated implants, some biomechanical problems such as loosening or fracture of the abutment, crown fixation screw loosening and prosthetic instability, are common problems reported in the literature. Thus, the objective of the present study was to analyze the pullout resistance of straight and angled abutments in narrow diameter implants installed by means of friction. The specimen was composed of an implant of 3.3 mm x 11 mm fixed 2 mm above of a resin block. The abutments were fixed by friction receiving 3, 5 and 7 strikes of 0.05 J along the implant axis, and were positioned with 0˚, 10˚ and 20˚ of angulation. The abutments were subjected to pullout load, totalizing 10 repetitions for each test, i.e., the abutment was reinserted up to 10 times in the same implant. The results showed higher values of pullout load for the abutments with 7 strikes, and no statistical difference with 5 strikes suggesting better mechanical stability.


  • IPEN-DOC 27567

    BERBEL, LARISSA O. ; VIVEIROS, BARBARA V.G. de ; MICELLI, ANA L. ; ROSSI, JESUALDO ; NIGRO, FREDERICO ; ARANHA, LUIS C. ; COSTA, ISOLDA . Effect of galvanic coupling between titanium alloy and stainless steel on behavior of corrosion of dental implants. International Journal of Advances In Medical Biotechnology, v. 3, n. 1, p. 23-27, 2020. DOI: 10.25061/ijamb.v3i1.68

    Abstract: Titanium and its alloys are widely used in dental implant manufacturing due its favorable properties, such as, biocompatibility, high mechanical strength and high corrosion resistance. This last one, is a result of the ability of titanium to form an oxide film (TiO2) in contact with oxygen. However, a several factors can accelerate the corrosion process of implants in contact with the oral environment, such as, acidification of the medium, differential aeration, inflammatory conditions, presence of protein and the junction of diferent metals. The goals of this research is to investigate the corrosion effect of galvanic coupling between titanium alloy (grade V) and stainless steel 316L. The investigative technique adopted was the scanning vibrating electrode technique (SVET) in phosphate buffer solution simulating inflammatory conditions. The results showed detrimental effects of acidity of the environment, induced by inflammatory conditions, accelerate the oxidation of Ti-6Al-4V. SVET maps and SEM images for the junction of the different metals showed that the region with the highest electrochemical activity it is at the interface between the metals, mostly concentrated on the Ti-6Al-4V alloy, depending on the conditions of the medium.


  • IPEN-DOC 27566

    RODRIGUES, GISELE N.; MORAES, CARLA A.P.; SEO, EMILIA S.M. ; GOMES, JOAO P.C. . Protocolos de eficácia de repelentes de insetos: abordagens teóricas / Insect repellent effectiveness protocols - theoretical approaches. InterfacEHS – Revista de Saúde, Meio Ambiente e Sustentabilidade, v. 15, n. 2, p. 66-80, 2020.

    Abstract: A incidência de doenças como dengue, malária e febre amarela que estão relacionadas aos mosquitos está aumentando e com isso a preocupação de pesquisadores para achar um meio de combater esses casos também cresce. Os principais vetores de doenças são da família dos culicídeos e dentro dessa família os que mais preocupam são: o Aedes, Culex e o Anopheles. As fêmeas são hematófagas e tem a capacidade de transmitir doenças e gerar novos mosquitos. Já os machos alimentam-se de carboidratos como: seiva, flores e frutos. Atualmente existem meios de combate que se baseiam em repelentes com a substância naturais e sintéticas e podem vir em forma física de aerossol, spray, creme, loção ou gel que buscam afastar os mosquitos e assim não acontece a picada. Este projeto tem como objetivo a revisão bibliográfica de protocolos de eficácia de repelente de insetos.


  • IPEN-DOC 27598

    LIMA JUNIOR, EDMAR M.; MORAES FILHO, MANOEL O. de; FORTE, ANTONIO J.; COSTA, BRUNO A.; FECHINE, FRANCISCO V.; ALVES, ANA P.N.N.; MORAES, MARIA E.A. de; ROCHA, MARINA B.S.; SILVA JUNIOR, FRANCISCO R.; SOARES, MARIA F.A. do N.; BEZERRA, ALANE N.; MARTINS, CAMILA B.; MATHOR, MONICA B. . Pediatric burn treatment using tilapia skin as a xenograft for superficial partial-thickness wounds: a pilot study. Journal of Burn Care & Research, v. 41, n. 2, p. 241-247, 2020. DOI: 10.1093/jbcr/irz149

    Abstract: This study aims to evaluate the efficacy of Nile tilapia skin as a xenograft for the treatment of partial-thickness burn wounds in children. This is an open-label, monocentric, randomized phase II pilot study conducted in Fortaleza, Brazil. The study population consisted of 30 children between the ages of 2 and 12 years with superficial “partial-thickness” burns admitted less than 72 hours from the thermal injury. In the test group, the tilapia skin was applied. In the control group, a thin layer of silver sulfadiazine cream 1% was applied. Tilapia skin showed good adherence to the wound bed, reducing the number of dressing changes required, the amount of anesthetics used, and providing benefits for the patients and also for healthcare professionals, by reducing the overall work load. The number of days to complete burn wound healing, the total amount of analgesics required throughout the treatment, burn improvement on the day of dressing removal, and pain throughout the treatment were similar to the conventional treatment with silver sulfadiazine. Thus, tilapia skin can be considered an effective and low-cost extra resource in the therapeutic arsenal of pediatric superficial partial thickness burns.


  • IPEN-DOC 27597

    LIMA JUNIOR, EDMAR M.; MORAES FILHO, MANOEL O. de; COSTA, BRUNO A.; ROHLEDER, ANDREA V.P.; ROCHA, MARINA B.S.; FECHINE, FRANCISCO V.; FORTE, ANTONIO J.; ALVES, ANA P.N.N.; SILVA JUNIOR, FRANCISCO R.; MARTINS, CAMILA B.; MATHOR, MONICA B. ; MORAES, MARIA E.A. de. Innovative burn treatment using tilapia skin as a xenograft: a phase II randomized controlled trial. Journal of Burn Care & Research, v. 41, n. 3, p. 585-592, 2020. DOI: 10.1093/jbcr/irz205

    Abstract: Skin substitutes are considered a useful alternative for occlusive dressings in the treatment of superficial burns as they reduce the frequency of dressing replacement. This phase II randomized controlled trial aimed to evaluate the efficacy of Nile tilapia (Oreochromis niloticus) skin as an occlusive xenograft dressing for the treatment of burn wounds in humans. In order to assess the use of tilapia skin, the following variables were evaluated: number of days for wound healing, the number of times the occlusive dressing was changed, use of anesthetics or analgesics, pain assessment using the Visual Analogue Scale, and evaluation of burn improvement on the day of dressing removal. In total, 62 participants completed the study. It was found that in participants treated with tilapia skin, complete reepithelialization occurred in significantly fewer days; reported pain intensity was lower (study arms B and C), the amount of anesthetics/analgesics required was lower (study arms B and C), and the necessity of dressing changes was significantly reduced in comparison with volunteers treated with silver sulfadiazine. In our study, the tilapia skin xenograft showed good efficacy as an occlusive biological dressing for burn wound treatment in humans.


  • IPEN-DOC 27596

    LIMA, C.R.R.C.; LIMA, R.J.S.; MACHADO, L.D.B. ; VELASCO, M.V.R.; LAKIC, L.; NORDENTOFT, M.S.; MACHUCA-BEIER, L.; RUDIC, S.; TELLING, M.T.F.; GARCIA SAKAI, V.; OLIVEIRA, C.L.P.; BORDALLO, H.N.. Human hair: subtle change in the thioester groups dynamics observed by combining neutron scattering, X-ray diffraction and thermal analysis. European Physical Journal - Special Topics, v. 229, n. 17-18, p. 2825-2832, 2020. DOI: 10.1140/epjst/e2020-900217-4

    Abstract: Hair analysis plays an important role in forensic toxicology and biomonitoring tests. However, cosmetic treatments cause changes to the hair. Thus, a better understanding of the hair’s structure and the factors that influence its composition is critical. It is known that oxidative treatments modify the hair chemical, structural and mechanical properties. These treatments also cause degradation of the melanin as well as of the structures present in the hair cuticle and cortex. Considering that the literature is unanimous regarding the increase in hydrophilicity and porosity promoted in human hair by bleaching, in this work we investigated how this oxidative damage is triggered. By combining several techniques, inelastic and quasi-elastic neutron scattering, differential scanning calorimetry, thermal gravimetric analysis and X-ray diffraction, we were able to connect the chemical and structural changes to a subtle dynamic modification of the proton mobility in the hair fibers. In addition, alterations in the thermal behavior evidenced a small denaturation of α-keratin intermediate filaments and a slight decrease in the amount of confined water in the hair fibers. Moreover, data obtained by neutron spectroscopy indicated that bleaching attacks the thioester groups of the proteins causing larger proton mobility of the hydrogenous components (water, protein and/or lipids).


  • IPEN-DOC 27595

    FRANCISCO, DANAE L. ; PAIVA, LUCILENE B.; ALDEIA, WAGNER; LUGAO, ADEMAR B. ; MOURA, ESPERIDIANA A.B. . Noncovalently functionalized halloysite nanotubes for use in reinforced polymer composites. ACS Applied Nano Materials, v. 3, n. 11, p. 11510-11516, 2020. DOI: 10.1021/acsanm.0c02600

    Abstract: The inorganic halloysite nanotube (HNT) is a promising type of naturally occurring fillers with many important uses in different fields. An HNT has a relatively low content of hydroxyl groups on its surface, which makes it relatively hydrophobic, although this is not always sufficient to guarantee good interfacial adhesion in composite systems. Further surface treatment is required to improve the compatibility of HNTs with polymer matrixes, maximizing interfacial interactions. The aim of the present work was to study a noncovalent functionalization of halloysite with 2,2′-(1,2-ethenediyldi-4,1-phenylene) bisbenzoxazole (EPB), based on electron transfer, for further use of EPB as a coupling agent in polymer/HNT compatibility. A set of characterization techniques were performed to evaluate the chemical and physical properties and evidence the functionalization. The results revealed the surface modification of halloysite upon functionalization. Emphasis was for powder wettability by tensiometry based on Washburn because no studies about halloysite powders using this technique could be found in the literature. The results demonstrate a reduction in the total surface energy of the system, usually accompanied by a reduction in the polar component upon HNT modification.


  • IPEN-DOC 27594

    LEVY, D. ; SORDI, G.M.A.A. ; VILLAVICENCIO, A.L.C.H. . Irradiação de alimentos no Brasil: revisão histórica, situação atual e desafios futuros. Brazilian Journal of Radiation Sciences, v. 8, n. 3, p. 1-16, 2020. DOI: 10.15392/bjrs.v8i3.1241

    Abstract: O presente artigo apresenta um panorama histórico da evolução do processo de irradiação de alimentos no Brasil, analisando questões regulatórias nacionais, técnicas utilizadas e aportes nos cenários social, sanitário e econômico. Esta revisão tem por objetivo fornecer à comunidade científica uma perspectiva abrangente sobre a atual situação da irradiação de alimentos no Brasil, proporcionando novas reflexões sobre eventos passados, limitações atuais e possibilidades futuras. São analisados e discutidos atuais fatores que limitam uma mais ampla utilização da irradiação de alimentos no país, dentre os quais, a carência de irradiadores que possam atender às distintas regiões do país. Finalmente, o artigo apresenta a equivocada percepção de risco por parte da população e a necessidade de ações para impulsionar a aceitação pública, dentre as quais, o desenvolvimento de programas de comunicação e informação junto ao público leigo que desconhece as contribuições das aplicações pacíficas da tecnologia nuclear.


  • IPEN-DOC 27593

    MOREIRA, TATIANA M. ; SEO, EMILIA S.M. . Caracterização e utilização de fibras de coco como biossorvente na recuperação de corpos hídricos contaminados por derramamento de derivados do petróleo / Characterization and use of coconut fibers as biosorbent in the recovery of water contaminated by spilling oil derivatives. Brazilian Journal of Animal and Environmental Research, v. 3, n. 4, p. 3771-3781, 2020. DOI: 10.34188/bjaerv3n4-078

    Abstract: Com base no desenvolvimento sustentável, este trabalho, visou buscar materiais tecnológicos com enfoque na reciclagem, onde se destacam as fibras vegetais, como as do coco, que possuem baixo custo e impacto ao meio ambiente, com boa eficiência quando utilizadas para o processo de biossorção. Este método vem sendo utilizado como um recurso para redução de problemas ambientais causados por contaminação em corpos hídricos, como córregos e rios urbanos, por derramamento de substâncias tóxicas, minimizando assim os impactos dos ecossistemas aquáticos, bem como a contaminação do solo. As fibras do mesocarpo do Coco são lignocelulósicas obtidas a partir de frutos dos coqueiros (Cocos nucifera L.), os quais crescem abundantemente em países de clima tropical, como o Brasil. A preparação destas fibras foi feita por meio de tratamentos físicos e químicos, tais como: lavagem, secagem, secção, mercerização (tratamento químico com agente alcalino que ataca a superfície da fibra, melhorando suas características de sorção) e caracterização. Esses procedimentos geraram um material que pôde ser empregado como um biossorvente. Como contaminantes, foram utilizados derivados do petróleo, tais como a gasolina e o óleo diesel. Na caracterização foram utilizadas técnicas de: Picnometria, Termogravimetria, Análise Elementar, Microscopia Eletrônica, Fluorescência de Raios X, Teor de Umidade e Cinzas, Retenção de água, Hidrofobicidade e Flutuabilidade. Para os ensaios práticos foram mensuradas a sorção de contaminantes tanto em sistema seco, onde os contaminantes estão em contato direto com os biossorventes, quanto aquoso, simulando um derramamento de óleo diesel e gasolina em um corpo hídrico. Os resultados demonstraram que o biossorvente testado possui boa capacidade sortiva nos dois sistemas testados. Portanto, dada a sua origem renovável e de baixo custo, este material se mostrou eficiente para a finalidade proposta.


  • IPEN-DOC 27592

    DIAZ, JULIO C.C.A. ; M'PEKO, JEAN-CLAUDE; VENET, MICHEL; SILVA JUNIOR, PAULO S. da. Unveiling the high‑temperature dielectric response of Bi0.5Na0.5TiO3. Scientific Reports, v. 10, n. 1, p. 1-11, 2020. DOI: 10.1038/s41598-020-75859-z

    Abstract: Understanding the physics behind changes in dielectric permittivity and mechanical response with temperature and frequency in lead-free ferroic materials is a fundamental key to achieve optimal properties and to guarantee good performance in the technological applications envisaged. In this work, dense Bi0.5Na0.5TiO3 (BNT) electroceramics were prepared through solid-state reaction of highgrade oxide reagents, followed by sintering at high temperature (1393 K for 3 h). In good agreement with previous reports in the literature, the thermal behaviour of dielectric response from these BNT materials showed the occurrence of a high-temperature diffuse-like permittivity peak, whose origin has been so far controversial. Thermally stimulated depolarization current, impedance and mechanical spectroscopies measurements were here conducted, over a wide range of temperature and frequency, to get a deep insight into the mechanism behind of this event. The approach included considering both as-sintered and reduced BNT samples, from which it is demonstrated that the broad high-temperature dielectric peak originates from interfacial polarization involving oxygen vacancies-related spacecharge effects that develop at the grain-to-grain contacts. This mechanism, that contributes to the anomalous behavior observed in the mechanical response at low frequencies, could also be responsible for the presence of ferroelastic domains up to high temperatures.


  • IPEN-DOC 27591

    TUSI, MARCELO M.; CANCIAN, RICARDO; POLANCO, NATALY S. de O.; VILLALBA, JUAN C.; ANAISSI, FAUZE J.; OLIVEIRA NETO, ALMIR ; SPINACE, ESTEVAM V. . Influência da fonte de carbono nas propriedades de híbridos Ni/Carbono preparados por carbonização hidrotérmica e tratamento térmico e utilizados como suportes para eletrocatalisadores PtRu/C / Influence of carbon source in the properties of Ni/Carbon prepared by hydrothermal carbonization and thermal treatment and used as supports for PtRu/C electrocatalysts. Revista Matéria, v. 25, n. 4, 2020. DOI: 10.1590/S1517-707620200004.1200

    Abstract: Neste trabalho, híbridos Ni/Carbono foram preparados em duas etapas (carbonização hidrotérmica e tratamento térmico a 900 °C sob argônio) a partir de diferentes fontes de carbono: glicose, amido e celulose. Eletrocatalisadores PtRu/C foram preparados pelo método da redução por álcool utilizando os híbridos como suportes. Os materiais foram caracterizados por espectroscopia por energia dispersiva de raios-X (EDX), análise termogravimétrica (TGA), espectroscopia no infravermelho com transformada de Fourier (FTIR), isotermas de B.E.T., difração de raios-X (DRX), microscopia eletrônica de transmissão (TEM) e voltametria cíclica em meio ácido. A eletro-oxidação do metanol foi estudada por cronoamperometria. O eletrocatalisador PtRu/C preparado utilizando o híbrido sintetizado a partir da celulose apresentou uma eletroatividade levemente superior aos demais materiais obtidos.


  • IPEN-DOC 27590

    RODRIGUES, BRUNO L.; BERTOTTI, VICTOR A.; FLOSI, ADRIANA A.; YORIYAZ, HELIO ; NUNES, MAIRA G. ; MAISTRO, CARLOS E.B.. Impacto dosimétrico de curvas CT-to-ED em irradiações de heterogeneidades de alto número atômico / Dosimetric impact of CT-to-ED curves on high atomic number heterogeneity irradiations. Revista Brasileira de Física Médica, v. 14, p. 1-9, 2020. DOI: 10.29384/rbfm.2020.v14.19849001578

    Abstract: Com a evolução dos sistemas de planejamento e a redução das incertezas no cálculo de dose, a correção de heterogeneidades se tornou necessária. A presença de ligas metálicas de alta densidade ainda é uma das limitações e fonte de imprecisão no cálculo de dose. Embora existam algoritmos de cálculo de dose precisos, a principal dificuldade está no estabelecimento de curvas de correção do número de Hounsfield (HU) para densidade eletrônica (CT-to-ED), para valores de HU apropriados. A maioria dos tomógrafos atuais trabalha em 12 bits, saturando o número de Hounsfield em torno de 3000 HU, sendo insuficiente para a maioria dos materiais de alto número atômico. No entanto, já existem equipamentos que operam com 16 bits e que não saturam na presença destes materiais, resultando em informações mais completas das propriedades físicas. O objetivo deste trabalho é avaliar, em irradiações de heterogeneidades de alto Z, o impacto dosimétrico quando são utilizadas curvas de correção que incluem altos valores de HU. Foram analisados os fatores que influenciam a construção da curva CT-to-ED e as fontes de incerteza no processo. As curvas foram introduzidas no sistema de planejamento e os resultados comparados com medidas experimentais. Os resultados indicaram que quando materiais de alto número atômico são incluídos na construção da curva CT-to-ED, existe uma dependência dessas curvas com a energia do tomógrafo. Observou-se uma maior concordância entre os dados medidos experimentalmente e os dados calculados, quando as curvas CT-to-ED expandidas para altos valores de HU são utilizadas pelos sistemas de planejamento.


  • IPEN-DOC 27589

    GONCALVES, FLAVIA; CAMPOS, LUIZA M. de P. ; SANCHES, LUCIANA K.F.; SILVA, LARISSA T.S.; SANTOS, TAMIRIS M.R. dos ; VARCA, GUSTAVO H.C. ; LOPES, DIANA P.; COGO-MULLER, KARINA; PARRA, DUCLERC F. ; BRAGA, ROBERTO R.; SANTOS, MARCELO dos; BOARO, LETICIA C.C.. Antimicrobial activity and physicochemical performance of a modified endodontic sealer / Atividade antimicrobiana e desempenho físico-químico de um cimento endodôntico modificado. Research, Society and Development, v. 9, n. 11, p. 1-16, 2020. DOI: 10.33448/rsd-v9i11.9401

    Abstract: Introduction: this study aimed to evaluate the antimicrobial and physicochemical properties of a commercial endodontic sealer modified by the addition of montmorillonite (MMT) nanoparticles loaded with two different drugs: chlorhexidine (CHX) or metronidazole (MET). Methods: 5 wt% MMT/CHX or MMT/MET nanoparticles were added to the sealer AH-Plus. The experimental materials were evaluated for drug release, antimicrobial activity, flow, flexural strength, and flexural modulus. Data were subjected to one-way ANOVA, Kruskal-Wallis, and Mann-Whitney tests. Results: The drug incorporation into MMT particles was 9% and 10% for CHX and MET, respectively. At 20 days after manipulation, 16.5% of the drug was released by the sealer with MMT/MET and 0.4% by MMT/CHX. The addition of both nanoparticles decreased the flow of materials, but they were still in compliance with ISO 6876-2012. The conversion, flexural strength, and flexural modulus of MMT/MET (87%, 37±7 MPa, 2.3 GPa) and MMT/CHX (78%, 29±2 MPa, 2.7 GPa) were similar in both groups but lower than in the control group (100%, 54±7 MPa, 4.0±0.7 GPa). Both experimental materials were able to form an inhibition halo for E. faecalis bacteria (CHX: 4.8±1.4 and MET: 4.0±1.6 mm), whereas the control group did not inhibit the microorganism. Conclusion: both formulations proposed as endodontic sealer presented effective antimicrobial activity and acceptable flow. The addition of MMT/CHX and MMT/MET particles decreased the conversion and mechanical properties, but further studies are required to clarify the clinical relevance of these properties.


  • IPEN-DOC 27588

    BENCHERIF, HASSAN; BÈGUE, NELSON; PINHEIRO, DAMARIS K.; DU PREEZ, DAVID J.; CADET, JEAN-MAURICE; LOPES, FABIO J. da S. ; SHIKWAMBANA, LERATO; LANDULFO, EDUARDO ; VESCOVINI, THOMAS; LABUSCHAGNE, CASPER; SILVA, JONATAN J. ; ANABOR, VAGNER; COHEUR, PIERRE-FRANÇOIS; MBATHA, NKANYISO; HADJI-LAZARO, JULIETTE; SIVAKUMAR, VENKATARAMAN; CLERBAUX, CATHY. Investigating the long-range transport of aerosol plumes following the Amazon fires (August 2019): a multi-instrumental approach from ground-based and satellite observations. Remote Sensing, v. 12, n. 22, p. 1-18, 2020. DOI: 10.3390/rs12223846

    Abstract: Despite a number of studies on biomass burning (BB) emissions in the atmosphere, observation of the associated aerosols and pollutants requires continuous efforts. Brazil, and more broadly Latin America, is one of the most important seasonal sources of BB, particularly in the Amazon region. Uncertainty about aerosol loading in the source regions is a limiting factor in terms of understanding the role of aerosols in climate modelling. In the present work, we investigated the Amazon BB episode that occurred during August 2019 and made the international headlines, especially when the smoke plumes plunged distant cities such as São Paulo into darkness. Here, we used satellite and ground-based observations at different locations to investigate the long-range transport of aerosol plumes generated by the Amazon fires during the study period. The monitoring of BB activity was carried out using fire related pixel count from the moderate resolution imaging spectroradiometer (MODIS) onboard the Aqua and Terra platforms, while the distribution of carbon monoxide (CO) concentrations and total columns were obtained from the infrared atmospheric sounding interferometer (IASI) onboard the METOP-A and METOP-B satellites. In addition, AERONET sun-photometers as well as the MODIS instrument made aerosol optical depth (AOD) measurements over the study region. Our datasets are consistent with each other and highlight AOD and CO variations and long-range transport of the fire plume from the source regions in the Amazon basin. We used the Lagrangian transport model FLEXPART (FLEXible PARTicle) to simulate backward dispersion, which showed good agreement with satellite and ground measurements observed over the study area. The increase in Rossby wave activity during the 2019 austral winter the Southern Hemisphere may have contributed to increasing the efficiency of large-scale transport of aerosol plumes generated by the Amazon fires during the study period.


  • IPEN-DOC 27587

    PASQUALINI, ALEXANDRE A. ; ARTHUR, VALTER . Efeito do cobalto-60 em fêmeas R. (B) microplus na postura e na incubação dos ovos / Effect of cobalt-60 on R. (B) microplus females on egg laying and incubation. Pubvet, v. 14, n. 2, p. 1-6, 2020. DOI: 10.31533/pubvet.v14n2a516.1-6

    Abstract: Este trabalho buscou avaliar os efeitos do Co60 na postura de fêmeas ingurgitas do carrapato R.(B) microplus na fase de pré postura e na eclodibilidade de seus ovos quando submetidas às doses de 0 a 400 Gy onde se constatou que a radiação ionizante afetou em aproximadamente 70% o peso da postura dos ovos destas fêmeas, que a taxa de eclosão dos ovos da Testemunha foi 68,2% maior que a menor dose ionizante, o Tratamento com 5 Gy, que quanto maior a dose de radiação, menor o índice de eclosões e nos tratamentos que receberam doses maiores de 20 Gy, não ocorreram eclosões das posturas, estabelecendo-se assim um marco para se estudar a aplicação de técnica do inseto estéril neste espécime.


  • IPEN-DOC 27586

    MARSCHICK, G.; SCHELL, J.; STÖGER, B.; GONÇALVES, J.N.; KARABASOV, M.O.; ZYABKIN, D.; WELKER, A.; ESCOBAR C., M.; GÄRTNER, D.; EFE, I.; SANTOS, R.A. ; LAULAINEN, J.E.M.; LUPASCU, D.C.. Multiferroic bismuth ferrite: perturbed angular correlation studies on its ferroic α-β phase transition. Physical Review B, v. 102, n. 22, p. 224110-1 - 224110-11, 2020. DOI: 10.1103/PhysRevB.102.224110

    Abstract: Work of numerous research groups has shown different outcomes of studies of the transition from the ferroelectric α-phase to the high temperature β-phase of the multiferroic, magnetoelectric perovskite Bismuth Ferrite (BiFeO3 or BFO). Using the perturbed angular correlation (PAC) method with 111mCd as the probe nucleus, the α to β phase transition was characterized. The phase transition temperature, the change of the crystal structure, and its parameters were supervised with measurements at different temperatures using a six detector PAC setup to observe the γ -γ decay of the 111mCd probe nucleus. The temperature dependence of the hyperfine parameters shows a change in coordination of the probe ion, which substitutes for the bismuth site, forecasting the phase transition to β-BFO by either increasing disorder or formation of a polytype transition structure. A visible drop of the quadrupole frequency ω0 at a temperature of about Tc ≈ 820◦ C indicates the α-β phase transition. For a given crystal symmetry, the DFT-calculations yield a specific local symmetry and electric field gradient value of the probe ion. The Pbnm (β-BFO) crystal symmetry yields calculated local electric field gradients, which very well match our experimental results. The assumption of other crystal symmetries results in significantly different computed local environments not corresponding to the experiment.


  • IPEN-DOC 27585

    GONCALVES, KARINA de O.; VIEIRA, DANIEL P. ; LEVY, DEBORA; BYDLOWSKI, SERGIO P.; COURROL, LILIA C.. Uptake of silver, gold, and hybrids silver-iron, gold-iron and silver-gold aminolevulinic acid nanoparticles by MCF-7 breast cancer cells. Photodiagnosis and Photodynamic Therapy, v. 32, p. 1-10, 2020. DOI: 10.1016/j.pdpdt.2020.102080

    Abstract: Background. Nanoparticles show promise for theranostic applications in cancer. The metal-based nanoparticles can be used both as photosensitizers and delivery vehicles. In bimetallic particles based on gold or silver and iron, a combination of the plasmonic features of the gold or silver components with the magnetic properties of the iron makes these hybrid nanomaterials suitable for both imaging and therapeutic applications. Herein, we discuss toxicity and cell internalization of metallic (silver and gold) and bimetallic (silver-iron, gold-iron, and silver-gold) aminolevulinic acid (ALA) nanoparticles. ALA can control the production of an intracellular photosensitizer, protoporphyrin IX (PpIX), commonly used in photodynamic therapy. Methods. Nanoparticles were synthesized by photoreduction method and characterized by UV/Vis spectra, Zeta potential, FTIR, XRD, and transmission electron microscopy. The amount of singlet oxygen generation by a yellow LED, and ultrasound was studied for gold, gold-iron, and silver-gold nanoparticles. Cytotoxicity assays of MCF-7 in the presence of nanoparticles were performed, and PpIX fluorescence was quantified by high content screening (HCS). Results. Red fluorescence observed after 24 h of nanoparticles incubation on MCF-7 cells, indicated that the ALA in surface of nanoparticles was efficiently converted to PpIX. The best results for singlet oxygen generation with LED or ultrasound irradiation were obtained with ALA:AgAuNPs. Conclusions. The studied nanoparticles present the potential to deliver aminolevulinic acid to breast cancer cells efficiently, generate singlet oxygen, and convert ALA into PpIX inside the cells allowing photodiagnosis and therapies such as photodynamic and sonodynamic therapies.


  • IPEN-DOC 27584

    ANJOS, CAROLINA dos; SELLERA, FABIO P.; RIBEIRO, MARTHA S. ; BAPTISTA, MAURICIO S.; POGLIANI, FABIO C.; LINCOPAN, NILTON; SABINO, CAETANO P.. Antimicrobial blue light and photodynamic therapy inhibit clinically relevant β-lactamases with extended-spectrum (ESBL) and carbapenemase activity. Photodiagnosis and Photodynamic Therapy, v. 32, p. 1-4, 2020. DOI: 10.1016/j.pdpdt.2020.102086

    Abstract: Introduction. The production of β-lactamases by Gram-negative bacteria is among the most important factors of resistance to antibiotics, which has contributed to therapeutic failures that currently threaten human and veterinary medicine worldwide. Antimicrobial photodynamic therapy and antimicrobial blue light have a broad-spectrum antibacterial activity against multidrug-resistant and hypervirulent pathogens. Objective. To investigate the ability of antimicrobial blue light to inhibit the hydrolytic activity of clinically relevant β-lactamase enzymes (i.e., KPC, IMP, OXA, CTX-M, and SHV), with further comparison of the inhibitory effects of antimicrobial blue light with methylene blue-mediated antimicrobial photodynamic therapy. Methods. Blue LED light (λ = 410 ± 10 nm) alone or red LED light (λ = 660 ± 10 nm) in combination with methylene blue were used to inactivate, in vitro, suspensions of Klebsiella pneumoniae strains producing clinically important β-lactamase enzymes assigned to the A, B and D Ambler molecular classes. Furthermore, β-lactamase activity inhibition mediated by antimicrobial blue light and methylene blue-mediated antimicrobial photodynamic therapy was measured by using the chromogenic β-lactam substrate nitrocefin. Results. β-lactamase activities were effectively inactivated by both visible light-based approaches. In this regard, antimicrobial blue light and methylene blue-antimicrobial photodynamic therapy led to a significant reduction in the hydrolysis of nitrocefin (81–98 %). Conclusion. Sublethal doses of antimicrobial blue light and methylene blue-mediated antimicrobial photodynamic therapy are equally effective to inhibit clinically significant β-lactamases, including extended-spectrum β-lactamases and carbapenemases.


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Autor: Maprelian

Título: loss of coolant

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Ano de publicação: 2015

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95% do RD apresenta o texto completo do documento com livre acesso, para aqueles que apresentam o significa que e o documento está sujeito as leis de direitos autorais, solicita-se nesses casos contatar a Biblioteca do IPEN, .

Ao efetuar a busca por um autor o RD apresentará uma relação de todos os trabalhos depositados no RD. No lado direito da tela são apresentados os coautores com o número de trabalhos produzidos em conjunto bem como os assuntos abordados e os respectivos anos de publicação agrupados.

O RD disponibiliza um quadro estatístico de produtividade, onde é possível visualizar o número dos trabalhos agrupados por tipo de coleção, a medida que estão sendo depositados no RD.

Na página inicial nas referências são sinalizados todos os autores IPEN, ao clicar nesse símbolo será aberta uma nova página correspondente à aquele autor – trata-se da página do pesquisador.

Na página do pesquisador, é possível verificar, as variações do nome, a relação de todos os trabalhos com texto completo bem como um quadro resumo numérico; há links para o Currículo Lattes e o Google Acadêmico ( quando esse for informado).



O gerenciamento do Repositório está a cargo da Biblioteca do IPEN. Constam neste RI, até o presente momento 20.950 itens que tanto podem ser artigos de periódicos ou de eventos nacionais e internacionais, dissertações e teses, livros, capítulo de livros e relatórios técnicos. Para participar do RI-IPEN é necessário que pelo menos um dos autores tenha vínculo acadêmico ou funcional com o Instituto. Nesta primeira etapa de funcionamento do RI, a coleta das publicações é realizada periodicamente pela equipe da Biblioteca do IPEN, extraindo os dados das bases internacionais tais como a Web of Science, Scopus, INIS, SciElo além de verificar o Currículo Lattes. O RI-IPEN apresenta também um aspecto inovador no seu funcionamento. Por meio de metadados específicos ele está vinculado ao sistema de gerenciamento das atividades do Plano Diretor anual do IPEN (SIGEPI). Com o objetivo de fornecer dados numéricos para a elaboração dos indicadores da Produção Cientifica Institucional, disponibiliza uma tabela estatística registrando em tempo real a inserção de novos itens. Foi criado um metadado que contém um número único para cada integrante da comunidade científica do IPEN. Esse metadado se transformou em um filtro que ao ser acionado apresenta todos os trabalhos de um determinado autor independente das variáveis na forma de citação do seu nome.

A elaboração do projeto do RI do IPEN foi iniciado em novembro de 2013, colocado em operação interna em julho de 2014 e disponibilizado na Internet em junho de 2015. Utiliza o software livre Dspace, desenvolvido pelo Massachusetts Institute of Technology (MIT). Para descrição dos metadados adota o padrão Dublin Core. É compatível com o Protocolo de Arquivos Abertos (OAI) permitindo interoperabilidade com repositórios de âmbito nacional e internacional.

1. Portaria IPEN-CNEN/SP nº 387, que estabeleceu os princípios que nortearam a criação do RDI, clique aqui.

2. A experiência do Instituto de Pesquisas Energéticas e Nucleares (IPEN-CNEN/SP) na criação de um Repositório Digital Institucional – RDI, clique aqui.