Reposiório IPEN: Recent submissions

  • IPEN-DOC 27673

    KLUMPP, R.E. ; VIVEIROS, B.G. ; SILVA, R.M. ; MAGNANI, M.; ANTUNES, R.A.; COSTA, I. . Corrosion protection for Aluminum surfaces of use in the aircraft industry by hybrid Sol-Gel/Cerium nanocomposite coating. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Localized corrosion is a threat for aluminum alloys structures used in the aircraft industry. Toxic and carcinogenic surface pre-treatments based on hexavalent chromium have been widely used due to its highly effective corrosion protection properties. However, since it has been increasingly banished from use, there is great interest in the development of surface pre-treatments by clean technology to replace those that generate toxic residues. In this work, a novel eco-friendly surface treatment based on an hybrid sol-gel/Cerium nanocomposite coating was proposed with the great advantage over other treatments proposed carried out in literature that consists in one single step process. The effect of this newly developed treatment on the morphology, chemical composition and corrosion resistance of an Alclad alloy (AA1230) surface used in the aeronautic sector was evaluated. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) analyzed surface morphology, whereas corrosion resistance was studied by electrochemical techniques and Neutral Salt-Spray Test (NSST). Chemical composition of the surface after treatment was analysed by X-ray photon electron spectroscopy (XPS). The results showed high corrosion resistance of the treated surface comparable to that provided by chromated surfaces. Besides, high adhesion of the treated surface to a varnish, indicated that it is a viable alternative for replacement of chromate layers obtained from solutions with hexavalent chromium ions. Advantages of the treatment are environmentally friendly, effective corrosion protection and low costs.


  • IPEN-DOC 27672

    CARDOSO, E.C. ; PARRA, D.F. ; SCAGLIUSI, S.R. ; KOMATSU, L.G. ; LUGAO, A.B. . Ionizing radiation compatibilization in bio-based blends from PBAT/PLA reinforced with bio-eggshell. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Plastics global annual production exceeds 300 million tons and 99% is originated from oil or fossil combustibles. The amount of plastics wastes utilized exceeds the amount into landfills, prejudicing effectively the environment. As an alternative, they are being slowly replaced by bioplastics, as PLA (poly-lactic acid) and PBAT (butylene adipate co-terephthalate). Food and dairy industries produce annually huge amounts of avian eggshells residues and their disposition presents a serious environmental risk. Bio-load from avian eggshells as polymers reinforcement is based in their higher benefits as resistance and rigidity besides being a friendly environmental material, degradable and renewable. PLA and PBAT are thermoplastics capable to be processed by conventional methods: nevertheless, due to their high interfacial tension, it is required the use of compatibilizers. In this work, additives and heat generally used as compatibilizers were replaced by e-beam radiation, at 150 kGy dose. PBAT/PLA blends were prepared at the weight ratio of 82 / 18 and 5.0 phr of PLA 150 kGy e-beam radiated, at 2.5, 5.0 and 10.0 phr of bio-eggshells. Samples were homogeneized in a co-rotating twin-screw extruder and further characterized for: DSC, TGA, FTIR, XRD and Mechanical essays.


  • IPEN-DOC 27671

    SCAGLIUSI, S.R. ; CARDOSO, E.C. ; LUGAO, A.B. . The degrading effects of the radiation on the properties of butyl rubber compounds. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Polymeric materials (plastics and rubber) have been contributing in a continuously and raising way for the generation of litter and industrial wastes discarded in landfills. Gamma ionizing radiation has capacity for changing structure and properties of polymeric materials and can be applied to almost all types of polymers; irradiation is an expectation for problem-solving of rubber wastes management that can be utilized as raw-materials or chemical additives. butyl rubber has excellent mechanical properties and oxidation resistance, as well as low gas and water vapor permeability. At the initial stage of irradiation the degradation of butyl rubber occurs predominantly via random chain-scission This work aims to the introduction of a new recovery technique for butyl rubber, by using processing via gamma-rays followed by shear. 5 kGy, 15 kGy, 25 kGy, 50 kGy, 100 KGy, 150 kGy and 200 KGy doses were used, in order to study the feasibility of butyl rubber for recycling. Doses within 5 to 25 kGy applied to butyl rubber and pointed toward a less degraded material.


  • IPEN-DOC 27670

    CAVALCANTE, A.K. ; BATISTA, J.G. ; MAZIERO, J.d. ; FERNANDES, B.V.; VIVEIROS, W.; ROGERO, S.O. ; ROGERO, J.R. ; LUGAO, A.B. . In vitro and In vivo toxicity of Gold nanoparticles synthesized and stabilized with phytochemicals. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Gold nanoparticles (AuNPs) are among the most widely studied metal nanoparticles for biomedical applications. AuNPs can be synthesized by chemical reduction. Several methods for this type of synthesis are described in the literature, one of them is the Turkevich method, which uses sodium citrate (CITR) as a reducing agent. Other methods were developed based on the use of solvent systems during nanoparticle production. Although they are efficient production methods, they are environmentally unviable. In order to address this issue, metabolites present in various plant extracts have been explored for the preparation of different AuNPs. Green nanotechnology is the nanotechnology aspect that aims to develop protocols to generate sustainable products and production processes, in order to minimize the use of toxic compounds. In this study, the phytochemicals chosen as reducing agents and stabilizers for AuNPs synthesis were mangiferin (MGF) and resveratrol (RESV). Due to their ability to interact with biological systems, along with various applications of AuNPs, their toxicity has become one of the most important concerns. Due to the increased production and use of AuNPs, their risk of reaching different environmental compartments and becoming available increases the importance of determining toxicity in various species of biological interest, such as microcrustaceans and fish. Zebrafish is an important animal model used in the areas of developmental biology, genetics, biomedicine, nanotoxicology and is also used in ecotoxicological assays. The aim of the study is to evaluate the toxicity level of MGF (MGF-AuNPs) and RESV (RESV-AuNPs) reduced and stabilized AuNPs in vitro and in vivo by comparing them with the classical AuNPs synthesis method described by Turkvich (CITR-AuNPs). The study has two strands, one of which is to evaluate the level of nanomaterial toxicity using the zebrafish animal model as a preclinical study, and the other to evaluate the level of nanomaterial toxicity using the zebrafish animal model as a study of environmental toxicity. Cytotoxicity assay according to ISO 10993-5, Zebrafish FET TEST according to OECD 236 and Microinjection Assay in Zebrafish embryos. Green nanotechnology has proven to be a valuable tool in the synthesis of AuNPs for toxicity, not requiring the use of solvents and potentially toxic substances. The toxicity of AuNPs varied according to the assay. In the cytotoxicity assay, IC50 was obtained from CITR-AuNPs, whose IC50 was about 72%, which corresponds to the Au concentration of 74.16 µg.mL-1. In FET, RESV-AuNPs caused delays in the hatching process of zebrafish embryos, and it was the only sample that could obtain the LC50 (4.41%, corresponding to the Au concentration of 6,57 µg.mL -1). In the assay in which AuNPs were microinjected into embryos, the concentration causing toxic effect was not found in 50% of the organisms.


  • IPEN-DOC 27669

    BARTOLOMEI, S.S.; BARTOLOMEI, M.R.; SILVA, F.A.; OLIVEIRA, A.A.. Use of biodegradable oils as an alternative cooling in quenching treatment. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Ferrous alloys stand out for their use in various branches of the mechanical industry, as they encompass a series of mechanical properties that directly influence their application. For their implementation to be successful, they must have a suitable microstructure, which provides steel with sufficient mechanical characteristics so that it can withstand various types of efforts resulting from its implementation. Heat treatments are responsible for developing this microstructure in a controlled manner, through a set of heating and cooling operations with controlled conditions of temperature, time, atmosphere and cooling speed, in order to change their properties or give them some features. One of the most conventional treatments used worldwide to impart mechanical resistance to steels is the quenching treatment, which consists of heating the metal to austenitization temperature, kept at the same temperature for a certain time and after cooling it rapidly in a liquid medium. great efficiency in the extraction of heat, which can be water, saline solutions, polymeric solutions and oils, in order to form a new microstructure, harder but more fragile than its initial state, called martensite, which after tempering, has its stress-free internal structure, increasing its toughness. The most common cooling medium of the last decades is mineral oil, which due to its viscosity, has excellent capacity to extract heat, but it is a great villain when it comes to environmental issues, an example of this is the increase of water contamination. underground, where mineral oils are the most abundant contaminants present in the analyzed samples of these sources. Due to these and other environmental problems, studies have been developed to obtain an alternative cooling medium as effective as mineral oil, but which has less environmental impact. One solution to this problem is to use compound oils from renewable and biodegradable sources such as vegetable oils. Therefore, this work studies the effects of tempering on SAE 1045 carbon steel and AISI 420 martensitic stainless steel, using biodegradable soy and castor oil as cooling medium. For this, the viscosity of the oils was measured at room temperature and heated to 70 °C, temperatures at which tempering treatments were performed on 10 x 20 x 20mm rectangular section specimens. The specimens were cut, embedded and polished to be characterized by optical micrograph and Vickers microhardness. The results showed that biodegradable oils have excellent stability to bath temperature variation and can be applied over large temperature ranges due to their high flash points. Regarding the hardness and microstructure formed inside the specimen, the vegetable oils were also efficient, presenting values very similar to mineral oil, being soy oil more efficient than castor oil due to its low viscosity influencing hardness of the pieces and also in the formation of martensite. Biodegradable oils have proven to be an alternative.


  • IPEN-DOC 27668

    MOURA, E.A. ; SANTOS, B.S. ; OLIVEIRA, R.R. ; RODRIGUES, R.C.. Synergistic effect of polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers for sustainable packaging applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Conventional food packaging is in general, not recyclable, based on practically undegradable petroleum-derived polymers, and consequently not selectively collected. Concerns over their environmental impact and sustainability issues posed by their production and disposal and trends have increased interest and driven the effort to generate biobased and biodegradable packaging to replace or complement the conventional ones. The aims of this work are to investigate the development of biocomposite films composed of biodegradable polylactic acid(PLA)/poly(butylene adipate-co-terephthalate) (PBAT) blend and cellulose nanowhiskers extracted from agro-waste and evaluate their potential use in sustainable food packaging application. Biocomposite films based on biodegradable PLA/PBAT blend containing 1-2 wt. % of cellulose nanowhiskers extracted from agro-waste were prepared by melt extrusion, using a twin-screw extruder machine and blown extrusion process. To evaluate the potential use in food packaging applications, the cellulose nanowhiskers' content on the morphological, mechanical and thermal properties of the as obtained biocomposite films has been assessed. In addition, cellulose nanowhiskers were characterized by TEM, DLS, XRD, and TG. The results showed that cellulose nanowhiskers addition leads to an important increase in thermal degradation temperature, melting enthalpy and tensile properties of biocomposite films. The increases in the melting enthalpy can be attributed to the increase in the crystallinity of PBAT/PLA biocomposite as a result of cellulose nanowhiskers' addition. Morphology and thermal tests were related to the properties of the films and confirmed that cellulose nanowhiskers were homogeneously dispersed into the matrix. Based on the results, this research demonstrated that the use of biodegradable polymer blend and cellulose nanowhiskers extracted from agro-waste represents an interesting alternative for the production of flexible biocomposite films for sustainable food packaging applications and for the development of eco-friendly technologies.


  • IPEN-DOC 27667

    BARTOLOMEI, M.R.; ISHIKAWA, O.; BARTOLOMEI, S.S.; MOURA, E.M. . UV Barrier influence according to the amount of TiO2 in PBAT biodegradable flexible film. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Manufacturing and consumption of polymeric products and packaging continues to grow despite concerns about environmental contamination due to improper post-consumer disposal, causing polymeric waste to emerge in increasingly remote places, polluting seas and soil, affecting flora, fauna and human health. Among these wastes are flexible food packaging. One of the alternatives to reduce this problem is the use of biodegradable materials, such as poly (butylene adipate-terephthalate) (PBAT), but the properties of this material do not meet all the needs of a food packaging, focus of this work. Additives and / or fillers must be added to improve the properties of this polymer, such as mechanical, thermal and barrier properties. One of the important features of a food packaging is the UV light barrier, as many products have shortened shelf life due to interaction with light. This work studies the effect of the addition of titanium dioxide (TiO2) particles to improve UV light barrier in biodegradable flexible PBAT films, with clay addition to improve mechanical properties. The films were obtained by melt processing so that the application is industrially and economically viable. For this, known amounts of TiO2 (0.1, 0.2 and 0.3 wt%) were added in a poly (vinyl alcohol) (PVA) solution, along with 0.5 wt% organophilized light green clay. This mixture was sonicated, poured onto PBAT pellets and oven dried. Then, the particle coated pellets were processed in a twin screw extruder, cooled and pelleted. Then the flexible film was produced in a flat die single screw extruder, thus producing 4 nanocomposites (PBAT + 0.5wt% Clay; PBAT + 0.5wt% Clay + 0.1wt% TiO2; PBAT + 0.5wt% Clay + 0.2wt% TiO2; PBAT + 0.5wt% Clay + 0.3wt% TiO2). The results of X Rays Diffraction (XRD), Scanning Electron Microscopy (SEM) and tensile test showed that the clay was exfoliated in the polymer matrix, allowing improvements in the mechanical strength and elongation of the films. UV-vis absorption assays showed that the higher the TiO2 concentration the higher the UV barrier.


  • IPEN-DOC 27666

    BARTOLOMEI, S.S.; BARTOLOMEI, M.R.; MOURA, E.M. ; WIEBECK, H.; OLIVEIRA, R.R. . Effect on flame propagation in recycled expanded polystyrene with flame retardant/white clay/titanium dioxide nanocomposite. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Polystyrene is widely used in construction due to its properties such as low density, heat resistance, durability and ease of processing and molding. However, it is highly flammable, releases a lot of heat and toxic smoke when exposed to a flame. However, in order for a material to be applied in habitable indoor environments, it must comply with fire safety standards, which predict the behavior of materials during their burning. Halogenated flame retardants have been used to reduce the spread of flame, but they are toxic and polluting, so more environmentally friendly products are being developed. Polymeric nanocomposites, formed by inorganic nanoparticles, have many advantages in flame retardation, such as low heat release rate, low smoke and toxic gas production. Alternatively, the organofilized, exfoliated or polymer-intercalated montmorillonite clay (MMT) can be used to form a nanocomposite with greater flame resistance. However, for the clay to achieve the results required by the standards, it is necessary to add a large amount of particles, which generates agglomerates in the material and losses in the mechanical properties. Therefore, the use of clays to improve flame resistance to the material must be accompanied by the use of other flame retardants. Thus clay will provide reduction in flammability and secondary flame retardant will provide ignition resistance. The addition of other particles, together with clay, can corroborate with the reduction in flame spread of the material, with titanium dioxide being used to increase thermal stability, UV light stability, mechanical properties as well as reduction in flame spread. In this work expanded polystyrene (EPS) from construction waste, with flame retardant in its composition, was recycled and plasticized with glycerol. In this polymeric matrix was added white clay and titanium dioxide in order to maintain the flameproof properties and improve the mechanical and thermal properties of the material. The results showed that it is possible to recycle EPS and maintain flame self-extinguishing through the material even in the presence of glycerol as plasticizer. The addition of white clay improved the mechanical properties of the material and increased thermal stability, but impaired the fire behavior of the material, ceasing to self-extinguish the flame immediately after extinguishing the external flame. Titanium dioxide (TiO2) kept the mechanical and thermal properties unchanged and reduced flame propagation in the specimen when compared to the results of clay nanocomposite.


  • IPEN-DOC 27665

    FUNGARO, D.A. ; CARVALHO, F.B. ; ROVANI, S. ; SANTOS, J.. Effect of experimental variables on the extraction of nanosilica prepared by sugarcane bagasse ash. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Sugarcane bagasse is one of the important biomass sources in Brazil, which is used as a fuel in the sugar industry. As a result, a large quantity of ash is generated and creates a serious disposal problem. The waste bagasse ash can be used as a valuable material to obtain nanosilica. Initially, NaOH was mixed with sugarcane bagasse ash (ash:NaOH 1:2 w/w) and the resultant mixture was fused at 350 °C for 30 min. Next, sodium silicate was solubilized in water and nanosilica was produced by neutralizing with acid. The structure, properties and yield of silica produced is strongly influenced by the extraction method used. Therefore, the silica extraction was conducted using various type of acid (hydrochloric, sulfuric and acetic), acid concentration (0.5; 4.0; and 8.0 mol L-1) and gelation pH (2, 4 and 7 for hydrochloric and sulfuric acids and 4, 5 and 7 for acetic acid). The synthesized nanosilica characteristics were studied using various techniques. Experimental results showed that hydrochloric acid and sulfuric acid produced nanosilica materials with similar yield and purity in each different process parameter. The production of nanosilica particles with the addition of acetic acid was the least favorable under the study conditions, probably due to its weak acid characteristic. The purity of all the synthesized silica nanoparticles is in the range of 94-98% and impurities such as sulfur and iron were presents as main minor compound. The study reveals that the industrial waste material sugarcane bagasse ash acts as an alternative source for the production of nanosilica powder widely used in areas such as ceramics, chemicals, catalysis, chromatography, energy, electronics, coatings, stabilisers, emulsifiers and biological sciences.


  • IPEN-DOC 27664

    PARRA, D.F. ; LIMA, V.d. ; LUGAO, A.B. ; COTRIM, M.H. . Synthesis and characterization of encapsulation of silver nanoparticles with luminescent methyl polymethacrylate (PMMA). In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Rare earths have improved their importance owing to optical properties not only in the research area, but also in industrial and technological areas. Due to it higher luminescent intensity, Eu3+ complexes are among the most studied rare earth complexes that present luminescence, due to the structures of their energy levels. Combination with high molar absorptive ligands can promote a high emission of the Eu3+ ions. The present study concerns to luminescent doped polymers from methyl polymethacrylate (PMMA) used as a matrix for the development of luminescent films. The rare earth complex [Eu (tta)3 (H2O)2] was synthesized and used as a precursor for the synthesis of the secondary complex [Eu (tta) 3 (TPPO)2]. Silver nanoparticles synthesized and encapsulated in luminescent polymeric system showed distint luminescence behavior in the presence of those nanoparticles. After synthesis, the films were characterized. Investigation of the thermal behavior used differential exploratory calorimetry (DSC) and thermogravimetric analysis (TGA) techiniques. The characteristic fine emissions of the metal ion from the 5D0 ? 7FJ transitions (J = 0-4) indicated the incorporation of Eu3+ ions from both complexes in the matrix. The films showed the increase of the luminescence intensification of secondary complex in relation to the precursor complex. When encapsulating the silver nanoparticles to the luminescent systems, the luminescence intensity of these materials increased under conditions of low concentrations of the complex.


  • IPEN-DOC 27663

    CARNEIRO, F.W.; KAWABATA, V.J.; JACOVONE, R.M. ; ANGNES, L.; GARCIA, R.H. ; SAKATA, S.K. . The synthesis of palladium nanoparticles by electron beam into graphene oxide and its electrochemical behavior. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: In this work, graphene oxide (GO) was synthesized by the modified Hummers method and was used as support for palladium nanoparticles to study its electrochemical behavior. The main objective was the incorporation of Pd on the graphene oxide by the electron beam irradiation at 40kGy and 80kGy doses. The GO-Pd nanocomposite was characterized by thermogravimetry analysis (TGA), X-ray diffraction (XRD), electron transmission microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV). The results were satisfactory, indicating success in incorporating the metal in the GO surface. CV studies were conducted using screen printed electrode modified with nanocomposite, SPE/GO-Pd, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferricyanide solution and its results showed a linear increase in the current. It can therefore be inferred that palladium /graphene oxide nanocomposites have a potential for sensors.


  • IPEN-DOC 27662

    KAWABATA, V.J.; CARNEIRO, F.W.; JACOVONE, R.M. ; ALMEIDA, E.V. de; GARCIA, R.H. ; CORIO, P.; SAKATA, S.K. . The synthesis of magnetite/reduced graphene oxide nanocomposites by electron beam for eletrocatalysis application. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: This work presents the synthesis of magnetite/reduced graphene oxide nanocomposites (MrGO) via electron beam. The graphene oxide (GO) was prepared according to a modified Hummers’ method and it was characterized using X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Raman spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), zeta potential analysis and cyclic voltammetry (CV) were used in order to investigate the structure and properties of MGO. The data showed GO was reduced using 40 kGy. The CV was performed by applying a MrGO layer on the working electrode of a screen-printed carbon electrode, at a scan rate of 50 mVs-1, potentials range from -0.5 V until 1.0 V in KCl medium (0.05 mol.L-1) adding aliquots of 4 mmol L ?1 ferrocyanide solution. Its results show a similar electrochemical response from both samples (maximum current: 45?A). It can therefore be inferred that magnetite/reduced graphene oxide nanocomposites have a potential for electrocatalysis application.


  • IPEN-DOC 27661

    NOTARIO, A.O.; RIELLO, F.N.; FERREIRA, K.d.; MEDEIROS, E.S.; FILHO, L.G.. Screen-printed electrodes functionalization using polimeric matrices. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Biosensors are analytical devices able of converting a biological response into a signal of another nature. In electrochemical biosensors electrode functionalization is a fundamental step. The surface of the electrode, where the interaction with the biological sample occur, must be properly treated so that the signal can be captured in the best way possible, without noise interference and for reproducibility. We aim in this work to use polymeric structures, called blanket, to stabilize the surface of screen-printed electrodes. The blankets are composed of hydrophilic and hydrophobic polymers blend enriched with nanomaterials and were manufactured using the solution blow spinning (SBS) technique. The blankets were placed in contact with the electrode surface and the functionalization by polymer deposition was induced through the current flow. Subsequently, the modification was validated from voltammetry readings and impedance spectroscopy. Scanning electron microscopy showed that there was no change in the microscopic surface of the treated electrodes. However, the blankets were able to improve the reading signal, increasing the active area and current flow and homogenizing the readings between the electrodes. These observed effects may be related to a chemical change in the electrodes and not a physical one. The strategy presented here has the advantage that the polymeric matrices are easy to obtain and inexpensive and can be enriched with various materials. Ensuring that the electrode functionalization step is efficient is essential for the construction of a biosensor, as it also ensures that the capture molecules deposit in a similar manner in each repetition. Finally, this standardization step enables new platforms to be built for disease diagnosis and detection of specific targets.


  • IPEN-DOC 27660

    RIELLO, F.N.; NOTARIO, A.O.; GOULART, I.B.; GOULART, L.R.. Electrochemical immunosensor using magnetic capture for disease diagnosis. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Immunosensors are small devices that use biological reactions, relying on antigen-antibody binding to form an immune complex. Methods involving this detection have shown great possibilities for the diagnosis of diseases, but there are still some limitations. In a search for new techniques to increase specific recognition between biomolecules and electrode surface adhesion with faster, lower cost and portability for point-of-care tests, an antibody-coupled magnetic nanoparticle capture system was developed in order to detect antigens in an electrochemical biosensor. Mycobacterium leprae samples were used as an experimental model of more accurate diagnostic tools for this disease. Magnetic iron oxide (Fe3O4) nanoparticles were bioconjugated by covalent binding with M. leprae specific antibody (anti-PGL-I) using EDC promoting direct binding and NHS for stability. Slit-skin smear from leprosy patients with different bacillus concentrations and healthy contacts (negative control) previously quantified by real-time PCR (qPCR / RLEP) were incubated with the bioconjugate and adsorbed on the modified screen-electrode work area. The readings were taken in cyclic voltammetry with portable potentiostat support electrolyte and the PSTouch smartphone software was used to interpret the results. Voltammogram curves have qualitatively discriminated positive from negative samples. Quantitative differences were given by means of logarithmic calculations of the highest values of oxidation peaks in cyclic voltammetry and calibrated based on the number of bacilli previously quantified by qPCR. The novel biosensor presented a detection range from 1 to 1,000,000 bacilli. Briefly, our immunosensor was the first successfully prototype demonstrated for M. leprae detection in direct biological samples from patients. The strategy of magnetic antigen capture proved to be efficient by increasing the sensitivity of the test, because this technique allows the recognition and precipitation of specific antigens. Although it has been used for a specific model, this type of sensor can be applied to different types of diagnostics using antigen and antibody recognition, as the methodology used for bioconjugation is not restricted to the antibody used here. It is also efficient for samples that are difficult to process and where the analyte concentration is low. It is important to emphasize that the new biosensor is portable, fast, sensitive, specific, low-cost and ideal for field screening programs.


  • IPEN-DOC 27659

    GOMES, D.S. . A survey of accident tolerant fuel composed of uranium dioxide sintered with graphene nanoplatalet. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Global energy demanded should grow by 30% between today and 2040, and nuclear capacity will expand on 83%. Forecast scenarios point out that developing countries will invest in increasing their energy capacity by 45%. Today, nuclear power generates around 11.2% of global electricity, also considered as carbon emissions-free. Humanity must face various challenges to nuclear energy production because of safety operations conditions. In 2011, it started strategic plans, as accident tolerant fuel (ATF) sponsored by government agencies, industries, and universities. ATF introduced concepts that represent enhanced thermal conductivity, improved mechanical response, and radiation stability. It should replace the conventional UO2, also extend the copy time for accident scenarios. Nowadays, it grows the application of carbon materials for electronic devices, aerospace, and nuclear technology. Graphene platelets diffused in UO2 can enhance thermal conductivity around 30% and improve mechanical strength. Using nanocarbon dispersion on the uranium matrix can achieve a lower thermal gradient. The route adopted the spark plasma sintering technique to avoid the graphitization of carbon atoms. At present, the sintering of UO2 may take up a few hours, high temperatures, and energy to furnaces. Graphene is a two-dimensional honeycomb lattice of carbon atoms. Carbon nanotubes are cylindrical shapes, showing diameters of 1-3 nm, formed by graphene sheets. The calculation of the performance of UO2-Graphene used a fuel system with many physical properties updated. UO2-Graphene shows enhanced thermal conductivity and increased the capacity to keep fission gas releases into ceramic fuel.


  • IPEN-DOC 27658

    GOMES, D.S. ; OLIVEIRA, F.B. . Thermal analysis of nuclear fuel using silicon carbide nanocomposite dispersion in UO2. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: After the Fukushima Daiichi disaster happened in Japan in 2011, it started a global effort to get more tolerant fuels. In 2019, the fleet of power reactors designated for electricity suppliers made up 451 power units, generating around 402 GWe. The nuclear power represents 11.2% of the electricity generated, avoiding about 1.2 GT of CO2. The civilian reactors are operating using the uranium dioxide (UO2) as the fuel, which shows poor thermal conductivity of 7.8 W/m-K at room temperature. The fuel temperatures can reach up until 1500 °C at regular operation. Silicon Carbide Nanotube (SiC-CNT) dispersed in the UO2 matrix containing 5 to 20% vol of SiC-CNTs permits to increases the thermal conductivity. The novel fuel concept improves the thermal conductivity of 30% with the addition of 5% of silicon carbide. The fuel pellet UO2-SiC/CNTs are sintered using Spark Plasma Sintering (SPS) with a hold time of 5 minutes, at 1300 °C, and a pressure of 40 MPa. The fuel mixture shows a better density, low porosity, and acceptable grain size distribution compared to traditional sintering routes. It simulated the fuel mixtures using fuel performance code FRAPCON adapted to the thermals and mechanic properties of compounds. This study showed the possibility of increasing the safety margins of nuclear fuel using the addition of a small fraction of nanocomposite.


  • IPEN-DOC 27657

    MOURA, E.A. ; SANTOS, B.S. ; ISHIKAWA, O.; SANTANA, J.G. ; BARTOLOMEI, M.R.; OLIVEIRA, R.R. . Graphene oxide nanosheets as fillers for thermoplastic-matrix nanocomposites. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Recent studies have shown that the synthesis of graphene oxide (GO) by chemical oxidation of graphite followed by its reduction is one's the most promising routes to prepare remarkable polymer/graphene nanocomposite materials with significant improvement of properties compared to the base polymer. The addition of a very small amount of reduced graphene oxide (RGO)in a polymer can enhance its properties, with respect to electrical conductivity, barrier resistance, stiffness, abrasion resistance, mechanical resistance, and fire retardancy. Numerous approaches have been established to prepare RGO from the desoxygenation of GO. This work presents the synthesis of graphene oxide by chemical oxidation of graphite followed by its photoreduction in aqueous dispersion using UV radiation and highlights some examples of RGO/thermoplastic-matrix nanocomposites prepared by melt processing. To evaluate the potential application of thermoplastic composites prepared, the RGO's content on the morphological, mechanical and thermal properties of the as-obtained nanocomposites has been assessed. In addition, GO/RGO nanosheets were characterized by ATR–FTIR, XRD, Raman, and FE-SEM. According to the results, it can be inferred that the addition of RGO leads to a remarkable improvement in the performance of thermoplastic-matrix nanocomposites and offers a competitive solution for various potential applications.


  • IPEN-DOC 27656

    PARRA, D.F. ; BASSETTI, C. ; KOMATSU, L.G. . Biocide effects of f nanoparticles of ZnO and ZnO-doped-Ag application in polymeric blend of HMSPP/SEBS. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    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 melting process. The obtained materials were evaluated by X-ray diffraction (XRD), Raman Spectroscopy, Differential Scanning Calorimetry (DSC), biocidal tests against the bacteria E.coli and S.aureus following the JIZ 2801 standard. The nanoparticles sized between 100-200nm have spherical form. HMSPP / SEBS / films incorporated with the nanoparticles AgNPs / ZnO showed biocidal effect against the bacteria E.coli and S.aureus.


  • IPEN-DOC 27655

    KOMATSU, L.G. ; OLIANI, W.L. ; LUGAO, A.B. ; PARRA, D.F. . Synthesis of TiO2-doped- Ag for biocide activity on SEBS/PP applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Antimicrobial activity represents a challenge for scientific community. Polymer processing conditions impose temperature limitation for stability of biocide nanoparticles. In the present work, we evaluate TiO2-doped-Ag synthesized in laboratory, utilizing P25 Degussa Titanium Dioxide as precursor. The main proposal is to improve the incorporation of Ag on TiO2. The nanoparticles was tested by reduction of colony units formation (CFU)(%), Dynamical Light Scattering (DLS) and Zeta potential values. On CFU tests, all samples showed biocide properties. The samples showed biocide effect on E.coli and S.aureus bacteriae. The same nanoparticle was tested after sterilization under gamma irradiation, and showed an increase on biocide effect against S.aureus bacteria. The obtained biocide material was processed in SEBS/PP to obtain biocide polymeric films. The new material was characterized by: forming colony units (CFU)(%), Differential Scanning Calorimetry (DSC), and Fourier Transformed Infrared (FT-IR).


  • IPEN-DOC 27654

    BALOGH, T.S. ; KADLUBOWSKI, S.; BONTURIM, E.; LUGAO, A.B. ; VARCA, G.H. . Influence of argon and nitrous oxide on the synthesis of PVP nanogels prepared by gamma radiation. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nanogels are innovative systems with great potential for use in chemotherapy, disease diagnosis, release of bioactive substances, vaccines, cell culture systems, biocatalysis, in the generation of bioactive scaffolds in regenerative medicine among other applications. The definition of this material can be directly derived from the definition of polymeric gel, that is, a two-component system consisting of a permanent three-dimensional network of linked polymer chains and solvent molecules filling the pores of this network. Its internal structure is similar to that of hydrogels however presents particle size range varying from 0 to 100 nm leading to several advantages. Nanogel production methods involve intramolecular crosslinking that can be achieved using ionizing radiation. This method avoids the addition of any additives allowing the reaction to be carried out in a pure polymer-solvent system and the production of nanogels for biomedical applications free from monomer and crosslinking agents or surfactants. In this work influence of argon and nitrous oxide on the formation of nanogels by gamma irradiation has been evaluated. The samples were prepared in duplicate in multipurpose cobalt-60 gamma irradiator using a 25 mM PVP solution. Samples were irradiated in argon and nitrous oxide conditions with doses from 1 kGy up to 25 kGy with 10 kGy/h dose rate. These samples were morphologically characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) as well as the pristine PVP solution. The mean particle size of the samples and the polydispersity index was performed in equipment Zetasizer Nano ZS - Malvern® and the determination of radius of gyration and molecular weight was performed in equipment Heleos - Wyatt®. It was observed in the conditions evaluated that saturation with argon or nitrous oxide promoted similar results except for 25 kGy dose. At this dose larger mean particle size and radius of gyration were observed in the sample saturated with nitrous oxide.


  • IPEN-DOC 27653

    NASCIMENTO, A.C. ; PASSOS, P.d. ; LIMA, M.M. ; GALISTEO JUNIOR, A.J.; VIEIRA, D.P. . Mouse mioblast (C2C12) spheroids structured using paramagnetic iron nanoparticles as an in vitro culture system of Toxoplasma gondii tachyzoites. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Tridimensional cell culture techniques became essential for understanding physiological processes that are obliterated or fainted in conventional bi-dimensional cultures. These techniques are prone to produce more realistic modeling of the complex environment of living tissues, leading to much better understanding of mammalian tissue organization. This work used magnetic levitation of cell aggregates (spheroids) by adsorbing iron nanoparticles to C2C12 mouse (Mus musculus) mouse line cells (ATCC # CRL-1772), which are suspended with magnetic fields. The cells formed three-dimensional bodies that were cultivated suspended in the air-liquid interface. Magnetite (Fe3O4) nanoparticles with mean diameter of approximately 50 nm were produced by an alkaline coprecipitation methodology under reduction by microwave energy. Composition and size of crystallites were determined by DRX analysis. Adsorption on cell membranes occurred after functionalization with poly-L-lysine. Work concentrations of nanoparticles did no induce cytotoxicity in C2C12 monolayer cultures. Transmission electron microscopy of spheroid sections showed some findings morphologically compatible to the shape of reproductive intracellular vacuoli of T.gondii after cell invasion, demonstrating an interaction of cells with parasites in three-dimensional models.


  • IPEN-DOC 27652

    MOREIRA, R.P. ; FELINTO, M.C. ; BRITO, H.F.. Synthesis of tungstates nanoparticles with luminescent properties. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nanomaterials doped with rare earth ions have attracted great attention due to their unusual optical and electronic properties which leads these materials to be looked at as potential materials for application in the fields of high performance luminescent devices, lighting, magnets, catalysts, medical diagnostics, markers biological luminescent, etc. The advantages of using lanthanide ions as luminescent markers are numerous: it is a safe, low cost method, has higher specificity, the tests are more sensitive and the luminescence can be measured quickly, with a high degree of sensitivity and accuracy. [1-3] Among the methods used in obtaining nanocrystals can be mentioned: coprecipitation, sol-gel, microemulsion, microwave, polymer precursor, among others. In recent years, the polymer precursor (Pechini) and combustion methods are being used with greater emphasis due to the race to obtain nanoparticulate compounds, with homogeneous morphology in order to improve the performance of luminescent materials with application in nanotechnology. The Ba(1-x)WO4:xEu3+ powders were synthesized using the Pechini method, where the solutions of the salts of the Ba2+ and Eu3+ percussors in the form of NO3 ions. The 1: 4 citric acid and ethylene glycol solutions were added in the form of heat and heat to form a polymer resin, the pH being adjusted to 7 with ammonium hydroxide so that a brown, transparent resin . This resin was heated at 300°C for 2 hours, resulting in a black mass, which was prepared for the preparation of the precursor in powder form. The precursor was calcined at a preset temperature of 900°C for the production of barium tungstate.


  • IPEN-DOC 27651

    ROCHA, M.d. ; ANDRADE, D.A. ; MOREIRA, P.G. ; STEFANIAK, I. ; MARTINS, J.G.. Investigation on the improvement of thermal properties of TiO2 nanofluids. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: This work aims to investigate the thermophysical properties of TiO2 nanofluids in the water base experimentally and also comparing results with existing literature data and theoretical models. Studies reveal that nanofluids present increasing in thermal conductivity and other important properties related to the heat transfer capacity compared to the base fluid. In this way, it can be classified as promising fluids for heat transport applications. As the proposal is to use it in high thermal flux systems, the survey of experimental measurements was performed to verify whose of the main parameters have more influence over such properties. Thermal conductivity, viscosity, surface contact angle and some visualization of nanoparticles in SEM were carried out in order to understand the nanofluids properties modifications. The TiO2 nanofluids in water base solutions were prepared for this study using the ultrasonic dispersion technique for three distinct volume concentrations: 0.1%, 0.01%, and 0.001%. Samples were initially prepared using an ultrasonic disrupter to make a homogeneous solution. This is an important step in sample analyses concerning the homogeneity influence on thermal conductivity measurements. With all samples prepared, some steps were followed to ensure the dispersion of nanoparticles and thus obtaining more accurate results Nanofluids samples were visualized in a scanning electron microscope (SEM) JEOL, model JSM 6701F at IPEN. Figure 2 shows the TiO2 nanoparticle's image observed. Preliminary tests for determining the thermophysical properties of nanofluids were: density, thermal conductivity, viscosity and surface contact angle. Concentration and temperature effects were investigated in preliminary tests for measurement of the thermal conductivity of nanofluids: this step consists of measuring the thermal conductivities and viscosities of nanofluids for all concentrations (0.001%, 0.01% and 0.1% vol.) at 15°C, 25oC and 35oC. ASTM D5334-08 (2008) describes the standard procedure for determining thermophysical properties and is based on the classical Linear Probe Method also known as the Transient Hot-Wire Method.


  • IPEN-DOC 27650

    BATISTA, J.G. ; FREITAS, L.F. ; CRUZ, C.C. da; LUGAO, A.B. ; RODRIGUES, A.S.; SANTOS, L.O.; PIRES, M.A. . Green nanotechnology: stability and interactions of gold nanoparticles obtained with Annona muricata extract. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Cancer is among the diseases with the highest mortality rate, with more than 100 different types that occur due to mutations in the genetic material of cells. It is the third leading cause of death worldwide after cardiovascular and infectious diseases. In addition, the number of diseases caused by oxidative stress that results from an imbalance between the formation and neutralization of oxidizing species is increasingly perceived. Oxidative stress is initiated by free radicals and their interactions with biological macromolecules, such as proteins, lipids and DNA, healthy human cells and cause damage to proteins and DNA, with lipid peroxidation. These changes contribute to cancer, atherosclerosis, cardiovascular and inflammatory diseases. All cells are exposed to oxidative stress and therefore oxidation and free radicals play an important role in the development of cancer. Medicinal plants have a special place in cancer management. Several cancer researchers have been carried out studies using traditional medicinal plants, to discover new therapeutic agents that do not have side effects associated with chemotherapeutic agents. Studies using the extract of Annona muricata L., popularly known as araticum, have demonstrated potential anti-inflammatory and anticancer action, due to its antioxidant and immunological properties. The objective of the present work was to develop gold nanoparticles using Annona muricata L. dry extract and verify their physical-chemical characteristics, such as size, shape, and stability. The results obtained show that it is possible to synthesize gold nanoparticles with potential applications in medicine using the extract of araticum. Characterization was performed using the techniques of UV-Vis spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy (TEM). The in vitro stability study of the gold nanoparticles synthesized with the araticum extract was carried out for thirty days. The nanoparticles showed to be stable in different media during this period and the monitoring was done by spectrophotometry.


  • IPEN-DOC 27649

    YAMAGATA, C. ; RODAS, A.C.; HIGA, O.Z. ; MELLO-CASTANHO, S. . Synthesis and characterization of a bioactive silicate ceramic from SiO2 nanoparticles. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Sol-gel and co-precipitation techniques have been used for synthesis of multiphase silicate ceramic from SiO2 nanoparticles. Non-aggregated colloidal SiO2 nano particles were initially prepared from a sodium silicate solution, by surfactant template sol-gel method. Afterward, calcium and magnesium hydroxides were co-precipitated on colloidal SiO2 nanoparticles surface. CaO-MgO-SiO2 sintered ceramic obtained from the synthesized powders were characterized by SEM,XRD and FTIR. In vitro tests were performed by soaking the sintered samples in the simulate blood fluid (SBF, at pH 7.25 and 37 ?C) to observe its bioactivity. After 7 days of immersion in SBF, the FTIR spectra analysis revealed that the material is bioactive, by the formation of hydroxyapatite on the surface of the sample. No toxic effect was found in the cytotoxicity tests with CHO (Chinese hamster ovary) cells.


  • IPEN-DOC 27648

    LIMA, V.d. ; PARRA, D.F. . Study of luminescent effects on PMMA films with Eu3+/Ag nanoparticles. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Lanthanides, which are part of rare earths, have attracted attention due to their optical properties, not only in the field of research, but also in industrial and technological areas. Eu3+ ions are among the most studied of rare earth complexes because they have higher luminescence due to the structures of their energy levels. Combination with high molar absorptive ligands may promote higher emission of rare earth ions. The luminescent polymer system used as markers was obtained from doping with rare earth complexes, incorporating a Europrium complex containing trifluoroacetonate anion (TTA) in the process of encapsulating silver nanoparticles in methyl polymethacrylate (PMMA). The study will show that by introducing metallic nanoparticles, such as silver, it is possible to enhance the emission intensity in the luminescence processes of lanthanide compounds. The study of luminescence properties was performed by the spectrofluorimetry technique, showing that by introducing silver nanoparticles it will be possible to verify an increase of luminescence of the material in low concentrations of Europium complex. It will also be possible to observe an increase in material thermal stability through Thermogravimetric Analysis (TGA / DTG) performed under N2 atmosphere.


  • IPEN-DOC 27647

    TAKARA, E.M. ; SOUZA, J.B. de ; CARVALHO, E.F.U. ; SILVA, A.S. . Kinects and factors on chemical dissolution of aluminum alloy AA6061 in NaOH alkaline media. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nuclear Medicine is the Field of science that uses radioactive materials in order to diagnose and treat human body deceases. One of the most used radioisotopes for images diagnose purpose is the metastable technetium-99 (99mTc) because of its low decay half life (6 hours) and energy emission of 140keV that ensures low exposition time with the capacity of generating high quality images. The 99mTc is generated by the molibdenum-99(99Mo) radioactive decay during about 66 hours. The 99Mo is fabricated via nuclear fission of low encriched uranium (LEU) through plate irradiation targets (UAlx). The irradiation target cladding is made of Aluminum alloy AA6061 and its substrate is composed by 235U powder scattered in an AA1050 matrix. In general, studies are made targeting the prevention of corrosion mechanisms but the chemical dissolution in alkaline media, under hot cells, are one of the steps required for the post-processing methods of irradiation targets The time spent after irradiation is an important factor because the half life radioactive decay of the produced radioisotopes is relative short, then the procedures of dissolution, extraction, purify and distribution must be optimized in order to increase efficiency. This work presents a study of the factors impact involved on the chemical dissolution of the cladding aluminum alloys (temperature, NaOH solution concentration and dissolution time) as well as the kinects of the process associating it with the formation and destruction of oxides using electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). It was found that the involved parameters contribute individually more effective and that there is no relevant association between the factors. Solution temperature showed to be the most influent factor following by exposition time. It was presented a equivalent circuit model which demonstrates the reaction kinects and the growing of passive layers that slow down the process before it turns up into a soluble phase.


  • IPEN-DOC 27646

    LANGE, C.N.; PELEGRINO, M.T.; KOHATSU, M.Y.; SEABRA, A.B.; BATISTA, B.L.; MONTEIRO, L.R. ; URZEDO, A.L.; JESUS, T.A.; GOMES, D.G.; OLIVEIRA, H.C.. Copper nanoparticles are an effective tool to increase endogenous nitric oxide and have beneficial effects on lettuce seedlings. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Copper oxide nanoparticles (CuO NPs) have been investigated as a solution for agriculture worldwide problems. CuO NPs are efficiently to inhibit several pathogens and they are been commercially used as nanopesticide. In addition, CuO NPs might be promising for plant growth, development and recovery of degraded soils. The molecular pathway leading to these remarkable features of CuO NPs administration may be related to nitric oxide (NO) signaling. NO is a molecular messenger related to abiotic and biotic stress responses. CuO NPs may increase copper ion in plant. The increase of copper ions is well known to decompose S-nitrosothiols (RSNO) and generate NO. Our purpose in this study was to investigate the effect of CuO NPs on lettuce (Lactuca sativa L.) seedlings and the role of NO in its process. CuO NPs were synthesized using green tea extract as the reductor agent. They showed an average size diameter of 6.6 ± 0.2 nm, as assessed by transmission electron microscopy (TEM). The lettuce seedlings were exposed to a wide CuO NPs concentration range of 0.2 to 300 µg mL-1 and the germination rate and radicle elongation were analyzed. CuO NPs concentrations under 40 µg mL-1 showed no phytotoxic behavior to lettuce seedling whereas concentrations equal or above 80 µg mL-1 showed moderate to strong phytotoxic behavior. The optimum concentration was found to be at 20 µg mL-1 which showed an enhancement of germination and radicle growth of lettuce seedling. To evaluate the overall oxidative stress of plant, the enzymes catalase (CAT), ascorbate peroxidase (APX), peroxidase activity (POD) and superoxide dismutase (SOD) were analyzed. SOD levels significantly decreased with the increase of CuO NPs concentration. The SOD enzyme is correlated to decrease reactive oxygen species (ROS), thus the observed toxicity in concentration above 80 µg mL-1 may be linked with higher levels of ROS. In addition, we quantified RSNO and nitrite (NO2-), measured by amperometric analysis, which are indicators of NO presence. RSNO and NO2- levels significantly increased with the increase of CuO NPs concentration. CuO NPs administration was effective to increase NO formation in plant. Low levels of RSNO and NO2- were observed to have beneficial effects to lettuce seedlings. Thus, CuO NPs concentration is a crucial factor to assurance its beneficial effect and the NO signaling pathway may have an important role underling this process.


  • IPEN-DOC 27645

    JACOVONE, R.M. ; COSTA, C.A.; SAKATA, S.K. . Chemical characterization of bacteria: graphene oxide/Ag nanocomposite interactions by atomic force microscopy -infrared spectroscopy. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 and carbon bond around 1620 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria. Atomic force microscopy -Infrared spectroscopy (AFM-IR) is a combined technique that allows nanoscale chemical characterization of biological–materials interactions. In this work, AFM-IR was used to map Escherichia coli in graphene oxide /silver nanocomposite (Ag/rGO). In Escherichia coli, it was observed absorption bands corresponding to amine I at 1660 cm-1 and amide II at 1550 cm-1 from proteins. On the other hand, when these bacteria were exposed to (Ag/rGO) typical absorption bands from carbonyl/carboxyl groups around 1745 cm-1 and carbon bond around 1620 cm-1 were also detected, showing the antibacterial activities of (Ag/rGO). The conventional atomic force microscope was used to elucidate the morphologic changes that occurred by internalization of nanocomposite into the bacteria.


  • IPEN-DOC 27644

    RIELLO, F.N.; VARCA, G.H. ; LIMA, C.S. ; FREITAS, L.F. ; FERREIRA, A.H. ; LUGAO, A.B. . Synthesis and purification of albumin-based nanoparticles crosslinked by radiation. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Protein-based nanoparticles have been proved a promissing alternative for the loading and delivery of chemotherapeutic agents, radiopharmaceutics and other drugs of interests, constituting a less toxic therapeutic option due to its biocompatibility and low or null side effects. The use of radiation to crosslink or form covalent bonds enables the controll of the crosslinking process, without the need for crosslinking agents, as well as provides sterilizations simultaneously, withouth generating toxic compounds or products. The present work targets the synthesis an purification of albumin-based nanocarrier crosslinked by gamma radiation for biomedical applications. For such purpose, albumin nanoparticles were synthesized using BSA at 20% ethanol (v/v) in 50 mM phosphate buffer on an ice bath prior to and after irradiation. Samples were exposed to gamma radiation at a minimun absrobed dose of 10 kGy at 5kGy.h-1 and purified using a SuperdexTM 200 Increase 10/300GL for isolating the crosslinked protein (high molecular weight) from the native BSA. After the purification, the fractions were characterized by electrophoresis, Uv, fluorescence and dynamic light scaterring. The nanoparticles were obtained in the range of 25-40 nm and purified into fractions of high molecular weight and the native ones. The high molecular weight fractions presented increased bityrosine levels if compared to the fraction corresponded to the native BSA. The yields of nanoparticle formation remains to be determined, but our results provided a clear evidence of the formation of radiation-crosslinked BSA nanoparticles and the role of bityrosine in the nanoparticle assembly.


  • IPEN-DOC 27643

    FRANCISCO, L.H. ; FELINTO, M.C. ; BRITO, H.F.. Hydrothermal synthesis of rare-earth doped nanoparticles for energy conversion and storage. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: In recent years, several classes of rare-earth doped luminescent nanoparticles have been drawing attention due to complex energy converting systems that can be structurally engineered to tune absorption and emission wavelengths, outlining novel materials and applications on photonics [1-2]. In this scenario, this work presents the development of rare-earth doped core-shell SrAl2O4:Eu2+/3+, Dy3+ nanoparticles prepared via hydrothermal synthesis and post-annealed on carbon monoxide reducing atmosphere, which exhibit appealing spectroscopic properties for solar energy conversion and storage. The prepared strontium aluminate phosphors were further amino-functionalized with 3-aminopropyltrimethoxysilane (APTMS) and ?-diketonate rare-earth complexes by microwave assisted synthesis [3], in order to enhance its absorption section and energy-transfer processes within the system. Prepared samples were analyzed by X-ray powder diffraction, which revealed a stable monoclinic phase of pure strontium aluminate accordingly to PDF34-379. Crystallite size was estimated by the Scherrer method, indicating dimensions of about 25 nm. Moreover, standard luminescence spectroscopy results of pure SrAl2O4:Eu2+/3+, Dy3+ showcased characteristic green Eu2+ emission assigned to the 4f65d1?4f7(8S7/2) interconfigurational transition under near ultraviolet excitation. It was also found that amino-functionalized samples display distinguished emission spectral profiles, as Eu2+ emission shifts on ?-diketonate coated samples, suggesting an effective interaction between the inorganic host-matrix, the silica network and the ?-diketonate complexes. Likewise, acquired excitation spectra monitored on Eu2+ emission revealed its characteristic broad band in the ultraviolet region, as well as non-reduced Eu3+ narrow absorption lines. In addition, ?-diketonate S0?Sn transitions were also observed on functionalized samples, unveiling an increasing absorption section under ultraviolet light. Finally, it is highlighted that prepared SrAl2O4:Eu2+/3+, Dy3+ persistent phosphors displayed intensifying characteristic green emission under UV light due to imposed surface modification processes by functionalization. Therefore, as its emission wavelength overlaps with a commonly used dye (N719) in dye-sensitized solar cells, the materials assembled in this work aspire to enhance energy conversion efficiency and storage on such photovoltaic devices.


  • IPEN-DOC 27642

    NOGUEIRA, K.M. ; VARCA, J.O. ; LIMA, C.S. ; CRUZ, C.C. da; RIBEIRO, A.H.; FREITAS, L.F. ; VARCA, G.H. ; LUGAO, A.B. . Development of Lignin/PEO nanofibers by electrospinning technique for tissue engineering application. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Lignin is a renewable carbon source and has been widely explored in different areas over the last years, especially in biomaterials such as dressings and other biomedical devices due its natural origin and low cost. Its chemical structure confers interesting properties such as antioxidant capacity, UV protection, bactericidal action and appropriate adsorption. Poly (ethylene oxide) (PEO) is used in electrospinning to facilitate the formation polymer fibers. The electrospinning technique has been largely explored in the bioengineering area towards designing nanomaterial with minimum defect and high surface area. The present work aimed the development of a lignin/PEO nanofiber by electrospinning technique. In practical terms, lignin/PEO solution was prepared following two different methods. In the first approach, polymer stock solutions were prepared in alkaline water by stirring at 70 °C. In the second, the polymer powders were mixed and dissolved together in dimethylformamide (DMF) under stirring at 80 °C. By both methods, PEO/lignin solutions were prepared at 10, 20 e 30% (w,v) solid content, at the ratios 99/1 and 95/5. For electrospinning parameters, the distance between ejector and plate collector was set to 15-20 cm, voltage to 20 kV and injection flow to 1 mL/h, chamber temperature to 40 °C and 30%. Nanofiber morphology was assessed by scanning electron microscopy and optical coherence tomography. Apparent porosity was measured by classical Archimedes method. Due to higher DMF dielectric constant compared to water, results showed that nanofibers made using DMF presented smaller beats formation and smaller fiber diameter. Nanofibers with higher solid content presented more uniform fibers with larger diameter. Nanofibers with higher lignin concentration presented larger number of beats and higher fiber diameter. However, lignin improved the system porosity in all cases. Further mechanical and biological experiments will be done, nevertheless, the nanofiber developed is a promising material to be applied in tissue engineering.


  • IPEN-DOC 27641

    MOURA, E.A. ; ISHIKAWA, O.; MANGIERI, F.; BARTOLOMEI, M.R.; BARTOLOMEI, S.S.; OLIVEIRA, R.R. ; FRANCISCO, D.L.; GUIMARÃES, K.. Sonochemical synthesis of reduced graphene oxide: methods and characterization. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The reduction of graphene oxide (GO) by a safe and eco-friendly route, without the use of harmful chemicals, has drawn much attention as one of the most promising routes to produce graphene nanosheets, a 2D material with excellent electrical and thermal conductivity, optical and mechanical properties. Graphite exfoliation is widely performed by the chemical reduction of GO, which is commonly produced by oxidation of graphite using a strong oxidizing agent by Hummers’ method. This work presents a study of the influence of sonochemical application on synthesis of reduced graphene oxide induced by UV radiation. Commercial graphite powder was used as raw material. Firstly, graphite powder was dispersed into a DMF/deionized water solution and ultrasonicated using a high intensity ultrasonic device for 1 8 hours in other to reduce the particle sizes. After, sonicated graphite samples were frozen for 24 hours and freeze-dried for 24 hours to obtain the powder. Graphite powder obtained with different particle sizes was used to prepared GO through a chemical route. GO prepared was dispersed into a DMF/deionized water solution, ultrasonicated using a high intensity ultrasonic device for 1-2 hours, frozen for 24 hours and freeze-dried for 24 hours. Finally, GO powder samples were dispersed in a mixture of isopropyl alcohol, acetone, and deionized water and irradiated using UV radiation by different irradiation time to obtain reduced GO (RGO). The GO and RGO were characterized by BET, ATR–FTIR, XRD, Raman, TG, and FE-SEM analysis. In addition, graphite samples were characterized by BET, SEM and XRD analysis. The results showed that sonochemical application has a fundamental role in the synthesis of GO nanosheets and RGO. Ultrasonically prepared GO exhibited higher surface area, higher crystallinity and higher oxidation efficiency with many hydrophilic groups. FE-SEM analysis of the GO showed that sonochemical application reduced the aggregated domains and close stacking of sheets on the GO surface and led to obtaining reduced GO with a smooth surface, fewer layers and significant effective surface area.


  • IPEN-DOC 27640

    LIMA, C.S. ; VARCA, G.H. ; OLIVEIRA, J.R. ; NOGUEIRA, K.M. ; SANTOS, F.A. ; RIBEIRO, A.H.; LUGAO, A.B. ; FREITAS, L.F. ; ROGERO, S.O. . CMC and PVA hydrogel containing papain nanoparticles for drug delivery. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Four hydrogel formulations of Carboxymethylcellulose (CMC) and Poly (vinyl alcohol) (PVA) were prepared with native papain (AP and BP) and papain nanoparticles (AN and BN) for drug delivery. The formulations were evaluated for their preliminary stability, protein distribution in the matrix and cytotoxicity. Three methods for sterilization purposes were compared: irradiation by 60Co source, electron-beam and UV light. The preliminary stability test confirmed that the system was stable since there was no precipitation or alteration of the organoleptic properties of the samples in the evaluated period. The distribution of proteins in the hydrogel was very homogeneous in all the formulations. Quantification of the enzymatic activity of papain after contact with the gel showed that native papain maintained its activity high (86% and 93% for AP and BP gels, respectively), whereas there was a considerable drop in the activity of the papain nanoparticles to 60.54% and 69.44% for AP and BP gels, respectively. Such loss of activity is attributed to processing and/or process steps. The cell viability assay showed that the polymer matrix shows no cytotoxicity, corroborating with the literature, since the material is biocompatible. Thus, it is possible to affirm that the developed system presents potential for biomedical application, either as a vehicle of papain itself or for the transport of other drugs through complexation with papain nanoparticles. However, the need for further studies of stability, controlled release capacity and biocompatibility is required.


  • IPEN-DOC 27639

    FREITAS, L.F. ; CRUZ, C.C. da; BATISTA, J.G. ; VARCA, G.H. ; LUGAO, A.B. ; PIRES, M.A. . Stability of gold nanoparticles in different ionic concentrations and pH: a comparison among synthetic protocols. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: There are several protocols for the synthesis of gold nanoparticles, and lately there is a trend for green methods in order to minimize the environmental impacts. The reduction of gold salts by epigallocatechin 3 gallate, for instance, generates stable and uniform nanoparticles without the use of toxic compounds, and so does the radiolytic synthesis protocol. For medical purposes, proteins like albumin and papain are useful coating agents, providing a better biological effectiveness. Here we present a comparison of different synthetic and protein coating protocols for gold nanoparticles regarding their stability in different NaCl concentrations and pH, aiming for the development of nanoparticles that are able to be administered in physiologic solutions to patients. The nanoparticles were synthesized via EGCG (2 mg mL 1) reduction of gold salt (5 mmol L 1) in phosphate buffer pH 7.0. Those nanoparticles were coated or not with albumin or papain (1 mg mL 1) using mercaptopropionic acid. Other protein coated gold nanoparticles were synthesized radiolytically by mixing 5 mmol L 1 NaAuCl4 with 1 mg mL 1 bovine serum albumin (BSA) or papain and 0.1 mol L 1 tert butanol. The solutions were irradiated with 10 kGy (60Co source, 5 kGy h 1) and the resulting suspensions were stored until use. The suspensions were added in 96 well plates to solutions with different pH and NaCl concentrations, and their absorption spectra were taken periodically to verify their stability. It was observed that BSA gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 72h. The papain gold nanoparticles synthesized by both protocols were stable in concentrations of NaCl varying from 0.1% to 14.4% up to 48h, but in 72h there was evidence of instability in the lowest and highest NaCl concentrations. The nanoparticles coated just with EGCG (without proteins) were stable in all NaCl concentrations and times, except in the highest concentration after 72h. Regarding the pH, BSA gold nanoparticles and papain gold nanoparticles synthesized radiolytically, as well as EGCG gold nanoparticles were stable at least in pH varying from 5 to 11, in all times analyzed. In conclusion, all the nanoparticles tested are able to be administered to patients in physiological solutions, which have pH around 7.4 and NaCl concentrations around 0.9%, without the risk of aggregation and loss of biological activity.


  • IPEN-DOC 27638

    MORAES, T.S.; FERREIRA, J.C. ; BERGAMASCHI, V.S. ; SPINACE, E.V. . Core-shell catalysts for ethanol steam reforming reaction. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Hydrogen can be produced from the steam reforming (SR) of biomass-derived liquids such as bioethanol. The SR of ethanol for hydrogen production has several advantages. However, one of the main barriers to the commercialization of this technology is the deactivation of the catalysts due to the formation of carbon. Therefore, the development of catalysts that are stable and resistant to carbon formation is necessary. Several strategies have been used to avoid the deposition of carbon on the surface of the catalysts. Cerium oxide, at high temperatures or in the presence of reducers, can easily change oxidation state to form a non-stoichiometric oxygen deficient oxide. This oxide has a strong tendency to remain in the fluorite structure even after considerable oxygen loss, stabilizing the structure with a high number of oxygen vacancies. Other approach to minimize coke formation is to control the size of metallic particle through modifications in the catalyst structure. According to the mechanism reported in the literature, carbon formation in these reactions are favored in large sizes of metal particle. Therefore, controlling particle size is essential to reduce carbon accumulation on the catalyst surface during ethanol reforming reactions. One strategy for inhibiting the sintering process of metal particles in catalysts is the development of core-shell catalysts. These catalysts feature a metal core covered with an oxide layer, which gives them unique characteristics. The core-shell structure also accelerates the transformation processes of the carbon formed at the metal-oxide interface, favoring the gasification reaction and consequently its elimination in the form of CO2. Das et all have synthesized an innovative sandwiched core-shell structured Ni-SiO2@CeO2 catalyst that showed high activity and stability at dry reforming of biogas with negligible coke formation. The aim of this work is to investigate the performance of the structurally modified Ni-SiO2@CeO2 catalyst in the form of a sandwiched core-shell to inhibit the formation of carbon and increase the stability of the catalysts in the SR of ethanol reaction. This new form of catalyst synthesis has proved very efficient in other reactions but is still very little studied in the ethanol SR reaction. Silica nano-spheres were synthesized by the Stöber method and Ni-SiO2 catalysts were prepared via a Ni-phyllosilicate precursor route. Ni-SiO2@CeO2 will be prepare using the fresh Ni-phyllosilicate spheres that will be coated with a thin layer of CeO2 using a precipitation method. Silica nano-spheres and Ni-SiO2 were calcined at 1273 K for 1 hour with air. Samples were analyzed using transmission electron microscope (TEM) and x-ray diffraction (XRD). SR of ethanol was performed in a fixed-bed reactor at atmospheric pressure. Prior to reaction, catalysts were reduced under pure hydrogen at 923 K for 1 h. The reactions were carried out at 673K and H2O/ethanol molar ratio of 3.0.


  • IPEN-DOC 27637

    BRITO, H.F.; FELINTO, M.C. ; FRANCISCO, L.H. ; SAULA, M.S.; MERIZIO, L.G.. Nanoparticles presenting the phenomenon of luminescent persistence make the difference in biological applications. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The persistent luminescent materials are an important class of light-induced energy storage materials, which have undertaken a long development process. Recently, there has been increasing interest in employing long persistence luminescent nanoparticles (LPLNPs) for in vivo imaging. Because the long afterglow of these nanoparticles can last for several hours after they are excited in vitro, real-time in vivo imaging can be achieved after injection without requiring any external illumination source. Thus, the SNR can be significantly improved by removing the background noise originating from in situ excitations. Moreover, the afterglow luminescence of near-infrared (NIR)-emitting long-persistence luminescent nanoparticles (NLPLNPs) (the afterglow wavelength varies from 650 nm to 900 nm) falls within the tissue transparency window, where light attenuation is largely due to scattering rather than absorption, which is advantageous for long-term in vivo imaging with deep penetration and a high SNR1-3. In this work, we will be discussed the synthesis of these LPLNPs, the characterization and the luminescent properties especially the persistent luminescence intensity and lifetime that are the two important parameters to evaluate the persistent luminescent properties of materials. It was expected the materials to have a very high luminescence intensity and long persistent lifetime. The development of rare-earth doped core-shell SrAl2O4:Eu2+/3+, Dy3+ nanoparticles prepared via hydrothermal synthesis and p-st-annealed on carbon monoxide, in reducing atmosphere, or materials like Li1,6M1,6Sn2,8O8:R3+ (M2+: Mg, Zn and Cd; R3+: Cr, Nd, Yb), etc prepared by microwave-assisted solid-state reaction, ceramics method and co-precipitation reaction generate materials with efficient persistent luminescence and will be discussed in terms of electronic structure and syntheses methodology. Moreover, standard luminescence spectroscopy results of pure characteristic green Eu2+ emission assigned to the 4f65d1?4f7(8S7/2) interconfigurational transition under near-ultraviolet excitation. Some of these materials have special behavior and present persistent luminescence in the near-infrared, NIR, which is very important in terms of biological application point-of-view.


  • IPEN-DOC 27636

    FELINTO, M.C. . Nanocrystals of BaWO4:Dy3+ and SrWO4:Dy3+ synthetized by green chemistry method. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Nowadays, the investigation of oxide based light emitting materials for white light emitting diodes (w-LEDs) or device applications have generated interest due to the advantages such as long lifetime, low energy consumption, high luminescence efficiency and environmental friendliness [1]. These qualities make them a strong candidate for the solid state lighting, display devices, optoelectronic devices and light-emitting diodes (LEDs). In this work, we present results of Dy3+: BaWO4 and Dy3+: SrWO4 that present luminescence close to white color (Figure 1) left. They were synthesized using co-precipitation method. The emission spectra exhibit four emission transitions centered at around 486 nm, 576 nm, 665 nm and 760 nm corresponding to the transitions 4F9/2?6H15/2 (blue), 4F9/2?6H13/2 (yellow) 4F9/2?6H11/2 and 4F9/2?6H9/2 6F11/2 (red) respectively. Among these transitions 4F9/2?6H15/2 and 4F9/2?6H13/2 are observed to be strong whereas 4F9/2?6H11/2 transition is found to be relatively quite weak. The 4F9/2?6H13/2 transition is hypersensitive in nature and is strongly influenced by the environment around the Dy3+ ion site. It is observed in the luminescence spectra of these materials that the electric dipole transition is dominant compared to the magnetic dipole transition. The CIE diagram show emission close to white (Fig.1 right) for the five composition with little distortion of the color showing the influence of dopant concentration in the color of the emission. Figure 1. Dy3+: BaWO4 under UV excitation (366nm) left, emission spectra under excitation at 350nm middle and chromaticity coordination diagram of BaWO4:Dy3+ material.


  • IPEN-DOC 27635

    FERREIRA, A.H. ; MARQUES, F.N.; SOUZA, L.E. de; VARCA, G.H. ; REAL, C.C.; FARIA, D.d.; JUNQUEIRA, M.d.; LUGAO, A.B. ; FREITAS, L.F. . Radiolabeled protein nanoparticles for cancer diagnosis. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: Recent advances in nanomedicine and nanotechnology have expanded the development of multifunctional nanostructures which combine specificity, diagnostic and therapeutic functions in nanostructured complexes in order to overcome biological barriers that may hinder the selective and effective administration and uptake of drugs and diagnostic agents in tumor tissue. Nanoparticles have been used in nuclear medicine as nano-radiopharmaceuticals to carry PET and SPECT ?- and ?-emitting radioisotopes used in endoradiotherapy to specifically destroy tumor tissue. The aim of the present work was the study of radiolabeling of albumin (BSA-NPs) and papain (P-NPs) nanoparticles synthesized by gamma irradiation, with 99mTc and characterize their in vitro and in vivo properties as potential novel nano-radiopharmaceuticals. Electron microscopy and light scattering techniques show spherical shapes of nanoparticles and average diameter of 9.3 ± 1.9 nm for P-NPs and 25.1 ± 2.9 nm for BSA-NPs. The radiolabeling reached around 90% yield, and the 99mTc-BSA-NPs showed stability for 24 h in all assayed conditions, while 99mTc-P-NPs presented stability for 6 h in human serum. The biodistribution studies in healthy animals have shown different excretion profiles, 99mTc-P-NPs featured a renal excretion. On the other hand the 99mTc-BSA-NPs were found in the liver and spleen to a larger extent, undergoing hepatic excretion. In vitro studies showed promising internalization rates for both nanoparticles with 74% and 57.6% of total uptake in MDA-MB231 cells, respectively for 99mTc-P-NPs and 99mTc-BSA-NPs. In vivo studies in micro-SPECT/CT images also showed a high tumor uptake for both nanoparticles. The autoradiographic studies and immunohistochemistry assays revealed a high density of both papain and BSA nanoparticles in peripheral regions of tumor tissue and confirmed the efficacy of the developed nano-radioparmaceuticals for targeting breast cancer.


  • IPEN-DOC 27634

    NOGUEIRA, B.R. ; SOUZA, C.D. ; CARVALHO, D.V. ; ROSTELATO, M.E. ; ROSERO, W.A. . A comparison of different coatings agents for gold nanoparticles obtained with a one-pot reaction with ascorbic acid. In: PAN-AMERICAN NANOTECHNOLOGY CONFERENCE, 2nd, March 4-7, 2020, Águas de Lindoia, SP. Abstract... 2020.

    Abstract: The materials at nanometric size sometimes present different characteristics when compared to the same material in macrometric scale. The gold nanoparticles (AuNPs) are an example, presenting different properties such as fluorescence, melting point, electrical conductivity, magnetic permeability, chemical reactivity, and even different color than usual. Those features are direct dependence on particle size, shape, and colloidal distribution. AuNPs have desirable attributes for medical applications such as excellent biocompatibility, low toxicity, and good optical and electronic properties. AuNPs are already widely used to carry nucleotides, antibodies, and proteins in addition to biotech applications. Spherical gold nanoparticles are mainly processed by Au3+ reduction to Au+ and Au0. With the use of a stabilizing ligand, the gold nanoparticles are capped and then further growth is avoided. In this work for each 100 mL of a 0.5 mM HAuCl4, 1 mL of 0.1 M L-Ascorbic Acid solution was added, as reduction agent, under a vigorous and constantly magnetic stirring at room temperature. Almost instantly, the reaction that was originally transparent, became black and then reddish, after continued stirring for 30 min more. Three different coating agents were used in this work (SH-PEG-NH2, Arabic Gum, and Biotin). A solution with 0.1 mM of each coating agent was prepared and then in a proportion of 1:1 they were added to the AuNPs solution and putted in an orbital shaker for 2 hours. For comparison a sample with just ultrapure water, instead of the coating agent was added. Bare AuNPs and each of the coated ones were compared by using dynamic light sizer (DLS) and UV-Vis, for size measurements; and Fourier transform Infrared spectroscopy was used to evaluate bonds between the nanoparticle surface and the coating agents. Preliminary results showed that AuNPs without any coating agent presented a total smaller size (ca. 51 nm) when compared with the (ca. 84 nm)coated ones. However UV-Vis peaks indicated that the cores of the coated AuNPs are probably smaller than the non-coated. The smaller core size may be due the addition of the coating agent stopping diffusion growth. FTIR was able to confirm the presence of the agents in the NPs surface. Further analysis such as transmission electronic microscopic should confirm these results.


  • IPEN-DOC 27633

    PIMENIDIS, JORGE A.; TERAM, ROGERIO; NASCIMENTO, MAURICIO S.; SANTOS, VINICIUS T. dos; SILVA, MARCIO R. da; COUTO, ANTONIO A. ; SANTOS, GIVANILDO A. dos. Análise do comportamento elétrico de ligas de alumínio obtidas por solidificação unidirecional. In: HOLZMANN, HENRIQUE A. (Org.). Resultados das pesquisas e inovações na área das engenharias 3. Ponta Grossa, PR: Atena, 2020. p. 11-22, cap. 2. DOI: 10.22533/at.ed.1332023112

    Abstract: O objetivo deste trabalho é analisar se a macroestrutura resultante de solidificação unidirecional influencia no comportamento elétrico da liga Al-6%Zn. O comportamento mecânico e elétrico de produtos industrializados, em muitas vezes significa dar garantias de durabilidade e solidez nas mais variadas aplicações de esforços e robustez de composição química. O ensaio de condutividade normalizado, norma técnica ASTM B193 – 02 (2014), utilizado neste trabalho é adotado industrialmente. O método de comparação dos resultados com a tabela de resistividade dos materiais foi adotado para análise dos resultados. Os resultados mostram que a macroestrutura resultante da solidificação praticamente não influencia na condutividade e resistividade elétrica da liga estudada.


  • IPEN-DOC 27632

    CIPRIANO, ARIOVALDO M.; CRUZ, RICARDO A. da; TERAM, ROGERIO; NASCIMENTO, MAURICIO S.; SANTOS, VINICIUS T. dos; SILVA, MARCIO R. da; COUTO, ANTONIO A. ; SANTOS, GIVANILDO A. dos. Análise da influência do processo de solidificação unidirecional no comportamento elétrico da liga Cu-8,5%Sn. In: HOLZMANN, HENRIQUE A. (Org.). Resultados das pesquisas e inovações na área das engenharias 3. Ponta Grossa, PR: Atena, 2020. p. 1-10, cap. 1. DOI: 10.22533/at.ed.1332023111

    Abstract: O objetivo deste trabalho é analisar se as variáveis térmicas de solidificação influenciam ou não no comportamento elétrico da liga Cu-8,5%Sn. A liga foi solidificada em uma lingoteira de aço inoxidável AISI 304, montada em um dispositivo de resfriamento unidirecional ascendente. O ensaio de condutividade elétrica foi realizado pelo equipamento ponte de Wheatstone, que mede a resistividade elétrica, e com o medidor de condutividade obteve-se os valores em %IACS, conforme norma ASTM B193-02. Como resultados, notou-se que a condutividade elétrica não foi influenciada pelas variáveis térmicas de solidificação, obtendo-se valores de IACS praticamente constantes para a liga de cobre estudada.


  • 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.

    Palavras-Chave: carbon; carbon oxides; environment; climatic change; greenhouse effect; amazon river; environmental degradation; environmental impacts; methane


  • 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.

    Palavras-Chave: methane; carbon monoxide; biomass; wetlands; amazon river; aircraft; troposphere; environmental impacts


  • 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.

    Palavras-Chave: carbon; deforestation; environmental degradation; climatic change; carbon oxides; amazon river; environmental impacts


  • 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.


  • IPEN-DOC 27583

    LIMA, CAROLINE S.A. de ; VARCA, JUSTINE P.R.O. ; NOGUEIRA, KAMILA M. ; FAZOLIN, GABRIELA N. ; FREITAS, LUCAS F. de ; SOUZA, ELISEU W. de; LUGAO, ADEMAR B. ; VARCA, GUSTAVO H.C. . Semi-solid pharmaceutical formulations for the delivery of papain nanoparticles. Pharmaceutics, v. 12, n. 12, p. 1-12, 2020. DOI: 10.3390/pharmaceutics12121170

    Abstract: Papain is a therapeutic enzyme with restricted applications due to associated allergenic reactions. Papain nanoparticles have shown to be safe for biomedical use, although a method for proper drug loading and release remains to be developed. Thus, the objective of this work was to develop and assess the stability of papain nanoparticles in a prototype semi-solid formulation suitable for dermatological or topical administrations. Papain nanoparticles of 7.0 ± 0.1 nm were synthesized and loaded into carboxymethylcellulose- and poly(vinyl alcohol)-based gels. The formulations were then assayed for preliminary stability, enzyme activity, cytotoxicity studies, and characterized according to their microstructures and protein distribution. The formulations were suitable for papain nanoparticle loading and provided a stable environment for the nanoparticles. The enzyme distribution along the gel matrix was homogeneous for all the formulations, and the proteolytic activity was preserved after the gel preparation. Both gels presented a slow release of the papain nanoparticles for four days. Cell viability assays revealed no potential cytotoxicity, and the presence of the nanoparticles did not alter the microstructure of the gel. The developed systems presented a potential for biomedical applications, either as drug delivery systems for papain nanoparticles and/or its complexes.


  • IPEN-DOC 27582

    LIMA, CAROLINE S.A. de ; BALOGH, TATIANA S. ; VARCA, JUSTINE P.R.O. ; VARCA, GUSTAVO H.C. ; LUGAO, ADEMAR B. ; CAMACHO-CRUZ, LUIS A.; BUCIO, EMILIO; KADLUBOWSKI, SLAWOMIR S.. An updated review of macro, micro, and nanostructured hydrogels for biomedical and pharmaceutical applications. Pharmaceutics, v. 12, n. 10, p. 1-28, 2020. DOI: 10.3390/pharmaceutics12100970

    Abstract: Hydrogels are materials with wide applications in several fields, including the biomedical and pharmaceutical industries. Their properties such as the capacity of absorbing great amounts of aqueous solutions without losing shape and mechanical properties, as well as loading drugs of different nature, including hydrophobic ones and biomolecules, give an idea of their versatility and promising demand. As they have been explored in a great number of studies for years, many routes of synthesis have been developed, especially for chemical/permanent hydrogels. In the same way, stimuli-responsive hydrogels, also known as intelligent materials, have been explored too, enhancing the regulation of properties such as targeting and drug release. By controlling the particle size, hydrogel on the micro- and nanoscale have been studied likewise and have increased, even more, the possibilities for applications of the so-called XXI century materials. In this paper, we aimed to produce an overview of the recent studies concerning methods of synthesis, biomedical, and pharmaceutical applications of macro-, micro, and nanogels.


  • IPEN-DOC 27581

    ORTIZ, ROBERTO G.; FREIRE, LUCIANO O.; SORDI, GIAN M.A.A. ; ANDRADE, DELVONEI A. ; CALDAS, LINDA V.E. . Fundamentos de proteção radiológica para condução de submarinos nucleares. O Periscópio, v. 71, n. 71, p. 104-108, 2020.


  • IPEN-DOC 27580

    ANDRADE, JESSICA L.F.; NOGUEIRA, GUILHERME B.; BELLINI, MARIA H. ; MANCUSO, FREDERICO; KLEINE, JOAO P.; SILVA, ISMAEL D.C.G.; PUNARO, GIOVANA R.; HIGA, ELISA M.S.. eNOS 894T allele can contribute to endothelial dysfunction but not QT interval prolongation in dialytic patients. Medical & Clinical Research, v. 5, n. 11, p. 291-297, 2020. DOI: 10.33140/MCR.05.11.01

    Abstract: Background: Cardiovascular complications are common in chronic kidney disease (CKD) patients. Endothelial nitric oxide synthase (eNOS) is very important for the homeostasis of the cardiovascular system, and its gene polymorphism at position 894 (G>T) has not been investigated with QTc interval in patients on dialysis. Objective: This study evaluated the association of the 894G>T polymorphism with QTc prolongation and endothelial dysfunction risk in dialysis patients. Methods: Predialysis blood samples were collected for eNOS gene polymorphism, nitric oxide (NO), thiobarbituric acid reactive substances (TBARS), total antioxidant, asymmetric dimethylarginine (ADMA) and L-arginine, and 12-lead electrocardiograms were analyzed in these patients. Statistics were based on continuous and categorical variables using Fisher’s exact or Chi-square or one-way ANOVA or Kruskal- Wallis tests. The results were considered significant when P < 0.05. Results: The study showed that the GG genotype was prevalent, with 54% of patients, followed by 41% GT and 6% TT, and the genotypic distribution was not associated with QTc prolongation. Furthermore, patients with the T allele showed increased ADMA, L-arginine and peroxidation lipid levels with reduced NO synthesis. Conclusion: Our study showed a lack of association between QTc interval and eNOS polymorphism; however, it was found that patients with the T allele had a greater risk of developing endothelial dysfunction by ADMA, which could contribute to future cardiovascular complications and worsening of CKD.


  • IPEN-DOC 27579

    FERREIRA, NELSON D.; LEAL NETO, RICARDO M. ; FILGUEIRA, MARCELLO; ALVES, MANUEL F.R.P.; SANTOS, CLAUDINEI dos; RAMOS, ALFEU S.. Effect of cobalt doping and milling time on microstructure and Vickers microhardness of the spark plasma sintered (67-x)Ti-xCo-22Si-11B (x = 2 and 6 at-%) alloys. Materials Research, v. 23, n. 6, p. 1-10, 2020. DOI: 10.1590/1980-5373-MR-2020-0337

    Abstract: Ti-6Al-4V and TiAl-based alloys are widely used for fabricating the implantable orthopedic devices and automotive components, respectively. Ti6Si2B-based alloys are attractive for use in orthopedic components because their higher hardness, superior biocompatibility and corrosion resistance in simulated body fluid than Ti and Ti-6Al-4V alloy. Limited information on Ti6Si2B stability in Co-dopped 67Ti-22Si-11B alloys are available in literature. This work presents the effect of cobalt doping and milling time on microstructure and Vickers microhardness of 65Ti-2Co-22Si-11B and 61Ti-6Co-22Si-11B (at-%) alloys produced by spark plasma sintering at 1100 oC for 12min using 20MPa. Samples were characterized by X ray diffraction, scanning electron microscopy, energy dispersive spectrometry, laser particle size analysis, and Vickers microhardness. Sintered alloys with 2 and 6at-%Co indicated the major presence of Ti6Si2B and Ti5Si3 dissolving up to 2.7 and 4.2 at-%Co, respectively, besides the minor precipitates of CoTi2 (4.4-16.7at-%Si) and CoTi (4.6-4.7at-%Si). Vickers microhardness of the sintered 65Ti-2Co-22Si-11B and 61Ti-6Co-22Si-11B alloys were in the range of 950-1050 and 1050-1150HV, respectively. Although the increase from 2 to 6at-%Co has reduced the Ti6Si2B stability, the Co-rich phases increased their hardness values up to 1150HV (11.3GPa), which are superior than those of commercial Ti alloys used for joint orthopedic components and automotive rotating parts.


  • IPEN-DOC 27578

    AVELAR, ALAN M.; GIOVEDI, CLAUDIA; ABE, ALFREDO Y. ; MOURAO, MARCELO B.. Oxidation of AISI 304L and 348 stainless steels in water at high temperatures. Materials Research, v. 23, n. 6, p. 1-7, 2020. DOI: 10.1590/1980-5373-MR-2020-0373

    Abstract: Oxidation of AISI 304L and 348 stainless steels was investigated in water at 1000 – 1350 °C by TGA, SEM, EDS, and Raman spectroscopy. Linear-Parabolic kinetics and multilayer oxide scales with voids were found for both alloys. Based on the experimental results, AISI 304L presented higher oxidation resistance and higher activation energy. Zircaloy-4 kinetic results were used for validation and performance comparison. In severe accidents conditions, stainless steel might lead to a faster hydrogen production comparing to Zircaloy.


  • IPEN-DOC 27577

    ALMEIDA, G.F.C. ; SUGAHARA, T.; ARBEX, A.A.; COUTO, A.A. ; MASSI, M.; MONTORO, F.E.; REIS, D.A.P.. Analysis of the surface treatments effect on the creep behavior of Ti-6Al-4V alloy. Materials Research, v. 23, n. 6, p. 1-9, 2020. DOI: 10.1590/1980-5373-MR-2020-0314

    Abstract: This paper compares the creep behavior of Ti-6Al-4V alloy after different surface treatments, the plasma nitriding using Plasma Enhanced Chemical Vapor Deposition (PECVD), and the deposition of SiC thin films with Cr interlayer using High Power Impulse Magnetron Sputtering (HiPIMS). A microstructural characterization was performed with Scanning Electron Microscopy (SEM), Scanning and Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS) techniques. The creep test was performed at a constant load from 500 to 600 °C and 125 to 319 MPa, and a fractographic analysis was performed. The EDS analysis of the plasma nitrided layer indicated the nitrogen presence of the compounds TiN and Ti2N and an increase in the iron concentration. Creep test results in both conditions indicated an increase in the creep resistance. Plasma nitrided condition indicated the lowest creep rate and lesser elongation, making it the most suitable in applications that require a low dimensional distortion.


  • IPEN-DOC 27576

    GUIMARAES, LUCCA B.; BOTAS, ALEXANDRE M.P.; FELINTO, MARIA C.F.C. ; FERREIRA, RUTE A.S.; CARLOS, LUIS D.; MALTA, OSCAR L.; BRITO, HERMI F.. Highly sensitive and precise optical temperature sensors based on new luminescent Tb3+/Eu3+ tetrakis complexes with imidazolic counterions. Materials Advances, v. 1, n. 6, p. 1988-1995, 2020. DOI: 10.1039/d0ma00201a

    Abstract: In the present work, new Tb3+/Eu3+ tetrakis(benzoyltrifluoroacetone) complexes containing imidazolic counterions were successfully prepared and characterized via elemental analysis, infrared spectroscopy, thermogravimetry, and X-ray powder diffraction. Photophysical features of the Eu3+ ion, such as the intrinsic emission quantum yields, radiative and non-radiative decay rates, and emission lifetimes were dramatically improved when compared with the data from the hydrated tris complex reported in the literature. The values found for the absolute emission quantum yields are up to 0.79 and ratiometric luminescent thermometers were built-up based on the ratio between the spectral areas of the 5D0 → 7F2 (Eu3+) and 5D4 → 7F5 (Tb3+) transitions. The best contactless temperature sensor operates in a wide temperature range (20–225 K) with a relative thermal sensitivity higher than 4% K−1 (maximum value of ∼7.6% K−1 at 20 K) and a temperature uncertainty lower than 0.1 K with a minimal lower than 0.01 K by combining excitation at the ligand (360 nm) and the Tb3+ ion (489 nm), illustrating the potential of lanthanide-based tetrakis complexes in the design of efficient luminescent thermometers.


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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.