Navegação por ano de publicação "2018"

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  • IPEN-DOC 26047

    SILVA, A.M.B.; JUNOT, D.O. ; CALDAS, L.V.E. ; SOUZA, D.N.. TL and OSL characterization of CaSO4:Tb, CaSO4:Tb,Ag, and CaSO4:Tb,Ag(NP). In: RUBIO, MARCELO (Ed.); TIRAO, GERMAN (Ed.) INTERNATIONAL SYMPOSIUM ON RADIATION PHYSICS, 14th, October 7-11, 2018, Córdoba, Argentina. Abstract... Córdoba: Centro de Excelencia en Productos y Procesos, 2018. p. 321-321.

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  • IPEN-DOC 25502

    BENTO, RODRIGO T. ; PILLIS, MARINA F. . Titanium dioxide films for photocatalytic degradation of methyl orange dye. In: YANG, DONGFANG (Ed.). Titanium Dioxide: material for a sustainable environment. London: IntechOpen, 2018. p. 211-225, cap. 11. DOI: 10.5772/intechopen.75528

    Abstract: The aim of this work was to characterize and evaluate the influence of the thickness on the photocatalytic efficiency of titanium dioxide thin films on the degradation of methyl orange dye under UV light irradiation. The films of 280 and 468 nm thick were deposited on borosilicate substrates at 400°C by the MOCVD technique using titanium isoproxide IV as precursor. XRD analyses showed the formation of anatase-TiO2 phase. Crosssectional FE-SEM images show that the films presented a dense columnar structure and grown perpendicularly to the substrate surface. The photocatalytic activity of the catalysts was studied using UV-vis spectrophotometry The TiO2 film with 468 nm of thickness presented higher photocatalytic activity exhibiting 69% of dye degradation. The increase of grain size and thickness of the films promoted an improvement of photocatalytic efficiency.

    Palavras-Chave: titanium oxides; films; chemical vapor deposition; photocatalysis

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  • IPEN-DOC 24732

    FONTES, MAYANA K.; GUSSO-CHOUERI, PALOMA K.; MARANHO, LUCIANE A.; ABESSA, DENIS M. de S.; MAZUR, WESLEY A.; CAMPOS, BRUNO G. de; GUIMARAES, LUCIANA L.; TOLEDO, MARCOS S. de; LEBRE, DANIEL ; MARQUES, JOYCE R. ; FELICIO, ANDREIA A.; CESAR, AUGUSTO; ALMEIDA, EDUARDO A.; PEREIRA, CAMILO D.S.. A tiered approach to assess effects of diclofenac on the brown mussel Perna perna: a contribution to characterize the hazard. Water Research, v. 132, p. 361-370, 2018. DOI: 10.1016/j.watres.2017.12.077

    Abstract: Pharmaceutical discharges into the aquatic ecosystem are of environmental concern and sewage treatment plants (STPs) have been pointed out as the major source of these compounds to coastal zones, where oceanic disposal of sewage occurs through submarine outfalls. Diclofenac (DCF) is one of the most frequently detected pharmaceuticals in water, but little is known about the effects on marine organisms. In this study, we employed a tiered approach involving the determination of environmental concentrations of DCF in marine water and the adverse biological effects for fertilization, embryo-larval development and biomarker responses of the mussel Perna perna. Results indicate that effects in fertilization rate and embryo-larval development were found in the order of mg$L 1. However, low concentrations of DCF (ng$L 1) significantly decreased the lysosomal membrane stability and COX activity, as well as triggered DNA damage, oxidative stress and changes in antioxidant defenses. Our results point to an environmental hazard at coastal ecosystems and suggest the need for improvements in the treatment of domestic wastewater aiming to reduce DCF concentrations, as well as regulation on current environmental legislation and monitoring of aquatic ecosystems.

    Palavras-Chave: drugs; aquatic ecosystems; seas; water pollution; contamination; sewage; environmental impacts; mussels; brazil

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  • IPEN-DOC 24728

    ERMAKOV, VIKTOR A.; SILVA FILHO, JOSE M.C. da; BONATO, LUIZ G.; MOGILI, NAGA V.V.; MONTORO, FABIANO E.; IIKAWA, FERNANDO; NOGUEIRA, ANA F.; CESAR, CARLOS L.; JIMENEZ-VILLAR, ERNESTO ; MARQUES, FRANCISCO C.. Three-dimensional superlattice of PbS quantum dots in flakes. ACS Omega, v. 3, n. 2, p. 2027-2032, 2018. DOI: 10.1021/acsomega.7b01791

    Abstract: In the last two decades, many experiments were conducted in self-organization of nanocrystals into two- and three-dimensional (3D) superlattices and the superlattices were synthesized and characterized by different techniques, revealing their unusual properties. Among all characterization techniques, X-ray diffraction (XRD) is the one that has allowed the confirmation of the 3D superlattice formation due to the presence of sharp and intense diffraction peaks. In this work, we study self-organized superlattices of quantum dots of PbS prepared by dropping a monodispersed colloidal solution on a glass substrate at different temperatures. We showed that the intensity of the low-angle XRD peaks depends strongly on the drying time (substrate temperature). We claim that the peaks are originated from the 3D superlattice. Scanning electron microscopy images show that this 3D superlattice (PbS quantum dots) is formed in flake’s shape, parallel to the substrate surface and randomly oriented in the perpendicular planes.

    Palavras-Chave: three-dimensional lattices; nanomaterials; nanoparticles; crystals; quantum dots; nanostructures

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  • IPEN-DOC 24797

    SILVA, P.S.M. ; ESPOSITO, V.; MARANI, D.; FLORIO, D.Z. de; MACHADO, I.F.; FONSECA, F.C. . Thermochemical stability of zirconia-titanium nitride as mixed ionic-electronic composites. Ceramics International, v. 44, n. 7, p. 8440-8446, 2018. DOI: 10.1016/j.ceramint.2018.02.039

    Abstract: Dense zirconia (8% molar yttria-stabilized ZrO2)-titanium nitride (TiN) composites are fabricated to obtain mixed ionic-electronic conducting ceramic systems with high degree of electronic and thermal conductivity. The composites are consolidated by spark plasma sintering (SPS), starting from pure powders of the pristine phases mixed in different ratios (TiN = 25, 50, 75 wt%). A careful optimization of the SPS conditions allows producing highly dense samples with no reaction between the phases or degradation by oxidation, thus maintaining the chemical integrity of the two phases. For all the composites, high electrical conductivity is attained. Samples exhibit metallic behavior, showing an unexpected percolation of TiN in the YSZ matrix for volume fraction ≤ 25 wt% (27 vol%). Chemical degradation and electrical properties of the compounds were monitored under oxidative (air) and inert (Ar) atmosphere at high temperatures. The oxidation kinetics of the nitride phase was inhibited by the microstructure of the composite. The electrical properties of such composites were explored at high temperature to evaluate its application in electrochemical devices. As results, it is shown that electrical transport properties of the composite can be tuned by both the relative volume fraction of phases and controlled oxidative treatments. Adjusting such parameters different electric behaviors were observed ranging from predominant electronic conductors, to temperature-independent resistivity, and semiconducting.

    Palavras-Chave: thermochemical processes; composite materials; zirconium oxides; titanium nitrides; yttrium oxides; plasma; electric conductivity; ceramics

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  • IPEN-DOC 24804

    UMBEHAUN, PEDRO E. ; TORRES, WALMIR M. ; SOUZA, JOSE A.B. ; YAMAGUCHI, MITSUO ; SILVA, ANTONIO T. e ; MESQUITA, ROBERTO N. de ; SCURO, NIKOLAS L. ; ANDRADE, DELVONEI A. de . Thermal hydraulic analysis improvement for the IEA-R1 research reactor and fuel assembly design modification. World Journal of Nuclear Science and Technology, v. 8, n. 2, p. 54-69, 2018. DOI: 10.4236/wjnst.2018.82006

    Abstract: This paper presents the sequence of activities to improve the thermal hydraulic analysis of the IEA-R1 research reactor to operate in safe conditions after power upgrade from 2 to 5 MW and core size reduction from 30 to 24 fuel assemblies. A realistic analysis needs the knowledge of the actual operation conditions (heat flow, flow rates) beyond the geometric data and the uncertainties associated with manufacturing and measures. A dummy fuel assembly was designed and constructed to measure the actual flow rate through the core fuel assemblies and its pressure drop. First results showed that the flow distribution over the core is nearly uniform. Nevertheless, the values are below than the calculated ones and the core bypass flow rate is greater than those estimated previously. Based on this, several activities were performed to identify and reduce the bypass flow, such as reduction of the flow rate through the sample irradiators, closing some unnecessary secondary holes on the matrix plate, improvement in the primary flow rate system and better fit of the core components on the matrix plate. A sub-aquatic visual system was used as an important tool to detect some bypass flow path. After these modifications, the fuel assemblies flow rate increased about 13%. Additional tests using the dummy fuel assembly were carried out to measure the internal flow distribution among the rectangular channels. The results showed that the flow rate through the outer channels is 10% - 15% lower than the internal ones. The flow rate in the channel formed between two adjacent fuel assemblies is an estimated parameter and it is difficult to measure because this is an open channel. A new thermal hydraulic analysis of the outermost plates of the fuel assemblies takes into account all this information. Then, a fuel design modification was proposed with the reduction of 50% in the uranium quantity in the outermost fuel plates. In order to avoid the oxidation of the outermost plates by high temperature, low flow rate, a reduction of 50% in the uranium density in the same ones was shown to be adequate to solve the problem.

    Palavras-Chave: thermal hydraulics; reactors; research reactors; uranium; fuel assemblies; iear-1 reactor; flow rate; loss of coolant; materials testing reactors; eccs

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  • IPEN-DOC 24778

    PORFIRIO, T.C. ; MUCCILLO, E.N.S. . Thermal and electrical properties of CaCu3Ti4O12 synthesized by soft chemistry route. Journal of Thermal Analysis and Calorimetry, v. 133, n. 2, p. 851–857, 2018. DOI: 10.1007/s10973-018-7184-0

    Abstract: Calcium copper titanate powders were synthesized by a soft chemistry route, aiming to establish a cost-effective solution method to obtain sintered ceramics with giant electric permittivity (ε′) and low dissipation factor (tanδ). Powders and sintered pellets were characterized by several techniques. The thermal decomposition behavior of the porous foam evidences that a hydroxycitrate was formed below 200 °C. Single cubic perovskite-type phase was obtained after calcination of the precursor powder at 700 °C for 5 h. Negligible mass loss occurs above 400 °C. During heating the precursor material, CuO is the first crystallized phase. A giant ε′ and low tanδ are obtained after sintering. The extension of the thermal window of ε′ is wider than those of powders prepared by other methods.

    Palavras-Chave: calcination; calcium compounds; ceramics; copper compounds; copper oxides; differential thermal analysis; dissipation factor; mass transfer; permittivity; perovskite; porous materials; synthesis; titanates

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  • IPEN-DOC 25133

    AKBARI-JEYHOUNI, REZA; OCHBELAGH, DARIUSH R.; MAIORINO, JOSE R.; DAURIA, FRANCESCO; STEFANI, GIOVANNI L. de . The utilization of thorium in Small Modular Reactors – Part I: neutronic assessment. Annals of Nuclear Energy, v. 120, p. 422-430, 2018. DOI: 10.1016/j.anucene.2018.06.013

    Abstract: This work presents a neutronic assessment to convert a Small Modular Reactor (SMR) with uranium core to the thorium mixed oxide core with minimum possible changes in the geometry and main parameters of SMR core. This option is due to most of SMR are designed to be strongly poisoned in the beginning of cycle and to have a long cycle. Thorium can be used as an absorber in the beginning of the cycle and also be used as a fertile material during the cycle, it seems to be a good option to use (Th/U)O2 as SMR’s fuel. The main neutronic objectives of this study is achieving longer cycle length for SMR by using the minimum possible amount of burnable poison and soluble boron in comparison with reference core. The Korean SMART reactor as a certified design SMR has been chosen as the reference core. The calculations have been performed by MCNP code for homogeneous and heterogeneous seed and blanket concept fuel assemblies. The results obtained show that the heterogeneous fuel assembly is the one which gives longer cycle length and used lower amount of burnable poison and soluble boron, and also consumes almost the same amount of 235U.

    Palavras-Chave: small modular reactors; thorium; smr reactor; m codes; feasibility studies; neutron reactions; fuel assemblies

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  • IPEN-DOC 25116

    MOREIRA, TIANA C.L.; AMATO-LOURENCO, LUIS F.; SILVA, GISELA T. da; ANDRE, CARMEN D.S. de; ANDRE, PAULO A. de; BARROZO, LIGIA V.; SINGER, JULIO M.; SALDIVA, PAULO H.N.; SAIKI, MITIKO ; LOCOSSELLI, GIULIANO M.. The use of tree barks to monitor traffic related air pollution: a case study in São Paulo–Brazil. Frontiers in Environmental Science, v. 6, n. 72, p. 1-12, 2018. DOI: 10.3389/fenvs.2018.00072

    Abstract: The analysis of chemical elements in the barks of trees is an alternative procedure to access spatial heterogeneity of traffic related air pollution. However, the role of tree species in the characterization of the variability of airborne pollution is poorly known. We present an observational study conducted in São Paulo, Brazil, based on the analysis of 498 trees from three common species: Tipuana tipu, Poincianella pluviosa, and Ligustrum sp. We considered ANCOVA models to compare the concentrations of Al, Fe, Zn, Cu, Mn, Ba, and S in the bark (periderm) of trees located close to streets with different levels of traffic intensity controlling for the extension of nearby green areas. The expected trend of increasing elemental concentration in the bark of trees located near streets with greater traffic intensity or close to smaller green areas was only fully evidenced by T. tipu. For instance, the concentrations of Zn, Fe, Al, and Ba increase by 200, 350, 230, and 280% respectively, for trees of this species located near arterial streets when compared to those observed near local streets. On the other hand, the concentrations of Zn, Fe, Al, and Ba are reduced by 41, 45, 50, and 30%, respectively, for trees located near green areas. For P. pluviosa, the capacity to suggest an association between the tree bark concentration of chemical elements with increasing levels of air pollution and presence of green areas was only fully observed for Zn and Cu. For Ligustrum sp., weaker and sometimes non-expected associations between bark concentrations of the chemical elements and either street classification or green area extension were observed. Our results indicate that the choice of species is a key element in the use of tree barks as a biomonitoring tool in urban landscapes. Species like T. tipu, with rough and highly porous bark, are the most appropriate for such purpose.

    Palavras-Chave: monitoring; biological indicators; air pollution; bark; x-ray fluorescence analysis; morphology; urban areas; environment; trees

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  • IPEN-DOC 27085

    MADI FILHO, TUFIC ; FERREIRA, ELSON B.; PEREIRA, MARIA da C.C. ; BERRETTA, JOSE R. . The use of the neutron activation analysis technique to determine heavy metals in Nicotiana tabacum solanaceae. In: INTERNATIONAL CONFERENCE ON RADIATION AND APPLICATIONS IN VARIOUS FIELDS OF RESEARCH, 6th, June 18-22, 2018, Ohrid, Macedonia. Abstract... Niš, Serbia: RAD Association, 2018. p. 348-348.

    Abstract: Tobacco addiction has been mentioned as a leading cause of preventable illnesses and premature disability and tobacco smoking is the main cause of lung cancer and one of the factors that most contribute to the occurrence of heart diseases, among others. The herbaceous species Nicotiana tabacum is a plant of the solanaceae family used for tobacco production. Some authors have researched about heavy metals and the toxicity of tobacco. Heavy metals are frequently found in low concentrations in ground, superficial and underground waters, even though it does not have environmental anthropogenic contributions. However, with the increase of the industrial activities and mining and the agrochemical use of contaminated organic and inorganic fertilizers, an alteration of the geochemical cycle occurs. As a consequence, the natural flow of heavy metals increases the release of these elements into the biosphere, where they are frequently accumulated in the superior layer of the ground, accessible to the roots of the plants. Traces of available heavy metals may be found in surface and subsurface aquatic systems and soils, even when there is no anthropogenic influence on the environment, and they frequently accumulate in the upper layer of the soil, where they are accessible to the roots of the plants. Except for the exclusion species, most plant species that grow on soil contaminated by heavy metals cannot avoid the absorption of these elements, but only limit their translocation. During planting and plant development, fertilizers and insecticides, including organochlorines and organophosphates, are used and the smoke from cigarette smoking presents various toxic substances, including heavy metals such as Chromium (Cr) and Manganese (Mn). The samples preparation procedures were carried out in our laboratories and submitted to the irradiation with thermal neutrons in the IPEN/CNEN-SP, in the IEA-R1 research reactor. The irradiated material was analyzed by gamma spectrometry using a high purity germanium detector (HPGe).

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  • IPEN-DOC 25343

    COUTO, C.P. ; COSTA, I. ; VIVEIROS, B.G. de ; ALENCAR, M.C. ; PANOSSIAN, Z.; ROSSI, J.L. ; COLOSIO, M.A.. The use of scanning vibrating electrode technique to evaluate the effect of hot stamping on corrosion resistance of press hardened steel 22MnB5 metallic coated with electroplated ZnNi. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 5149-5149.

    Abstract: The carmakers and all their production chain must achieve worldwide targets of lightweight, safety and reduced fuel consumption. The use of ultra high strength steel, such as press-hardened steels (PHS), in vehicle structures has been contributing with this. This type of steel is widely used in hot stamping process, which consists in heating the steel blank to the total austenitization temperature, and then transferring it from the furnace into the die where the steel is deformed and quenched at the same time, with a minimum cooling rate of 27 K/s. The boron-manganese PHS steel comprises perlite and ferrite microstructure, and its tensile strength is around 600 MPa in the annealed condition. Thus, after the hot stamping process the PHS microstructure completely changes to martensite and the tensile strength increases to 1500 MPa or more. The transferring step is a critical one, due to the contact of the hot steel blank with the atmospheric air; as consequence, it causes the steel oxidation. To avoid that, the steel is protected with metallic coatings. The hot-dip AlSi is the most currently used coating for this application, however, in order to keep up with the high PHS demand, alternative coatings, like zinc-base is under investigation. This work had the objective of evaluating the corrosion resistance of PHS, 22MnB5 grade, coated with electroplated ZnNi before and after hot stamping, using scanning vibrating electrode technique (SVET). The corrosion-localized techniques are more suitable, once the results showed that after hot stamping the coating layer changes completely, as a result of chemical elements diffusion. Thus, different phases of Zn-Fe-Ni are formed and random distributed which impacts the corrosion resistance of the steel.

    Palavras-Chave: corrosion resistance; surface coating; steels; ferrite; scanning electron microscopy; perlite; hardening; pressing; zinc; nickel; coatings

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  • IPEN-DOC 25601

    ANA, PATRICIA A.; SILVA, ELIZABETE dos S.F.; BENETTI, CAROLINA; AMARAL, MARCELO M. ; ZEZELL, DENISE M. ; GOMES, ANDERSON S.L.. The use of optical coherence tomography for the evaluation of the effects of an infrared laser on dentin demineralization. In: BIOPHOTONICS CONGRESS: BIOMEDICAL OPTICS, April 3-6, 2018, Hollywood, Florida, USA. Resumo expandido... Washington, DC, USA: OSA, 2018.

    Abstract: The effect of Er,Cr:YSGG laser on dentin demineralization was evaluated by optical coherence tomography, which was able to quantify and to evidence that this laser is a promissory alternative for preventing dentin caries.

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  • IPEN-DOC 25568

    FERREIRA, EDUARDO ; VIEIRA, LUDMILA ; FERREIRA, RAFAEL V. de P. ; MARUMO, JULIO T. . The use of macrophytes as biosorbents in radioactive liquid waste treatment. In: WASTE MANAGEMENT CONFERENCE, March 18-22, 2018, Phoenix, Arizona, USA. Proceedings... 2018. p. 1-4.

    Abstract: An important stage of the management of radioactive liquid waste is the chemical treatment. In the last few years, biosorption has attracted attention as one alternative method to remove radionuclides in liquid LL/ILW due to its efficiency and low costs. There are many biomasses that can be applied for this purpose, as agricultural residues and Macrophytes. This study aims at studying Macrophytes (Pistia Stratiotes, Limnobium Laevigatum, Lemna sp and Azolla sp) ability to absorb uranium in liquid solutions. The biosorption capacity of uranium by the Macrophytes was experimentally determined. The experiments determine the metal uptake after the solution was in contact with each biosorbents by inductively coupled plasma optical emission spectrometry (ICP-OES). The results show that these materials are potentially applicable in the treatment of liquid radioactive waste.

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  • IPEN-DOC 24802

    TANGO, RUBENS N.; ARATA, ANELYSE ; BORGES, ALEXANDRE L.S.; COSTA, ANNA K.F.; PEREIRA, LUCIANO J.; KAMINAGAKURA, ESTELA. The role of new removable complete dentures in stimulated salivary flow and taste perception. Journal of Prosthodontics - Implant Esthetic and Reconstructive Dentistry, v. 27, n. 4, p. 335-339, 2018. DOI: 10.1111/jopr.12507

    Abstract: Purpose: To evaluate the effect of replacement of inadequate complete dentures on salivary flow and taste perception in geriatric patients. Materials and Methods: Thirty-three patients, 13 males and 20 females, with amean age of 64.4 years were submitted to stimulated and unstimulated salivary flow rate and salivary pH measurements, and sense of taste evaluation. Tests were performed 3 months before complete denture substitution and 3 weeks after denture insertion. Results: The mean for unstimulated saliva (USS) was 2.1 ml before and 2.7 ml after replacement (p = 0.003). The mean volume of stimulated saliva was 6.3 ml before and 8.2 ml after replacement (p = 0.004). The pH mean of USS was 7.8 ± 0.44 before and 8.02 ± 0.41 after replacement (p = 0.005). No statistically significant difference was determined in the sense of taste before and 3 weeks after complete denture replacement. Conclusions: The replacement of inadequate complete dentures increases saliva flow; however, it does not improve taste perception.

    Palavras-Chave: dentistry; oral cavity; patients; saliva; salivary glands; prostheses; aged adults; elderly people

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  • IPEN-DOC 25426

    MATOS, B.R. ; REY, J.F.Q.; MERINO, D.H.; SILVA, J.S. da ; SCHADE, U.; PUSKAR, L.; FONSECA, F.C. . The relation between the alpha/beta relaxation dynamics and the shape of ionomer building blocks. In: CONGRESSO BRASILEIRO DE ENGENHARIA E CIÊNCIA DOS MATERIAIS, 23., 04-08 de novembro, 2018, Foz do Iguaçu, PR. Resumo... 2018. p. 8629-8629.

    Abstract: The relation between the alpha/beta relaxations and the shape of the building blocks of ionomer materials is a key factor for programming an important temperaturedependent property: the memory of shape [1,2,3]. However, the morphology of ionomers is indirectly obtained via modeling of small angle X-ray scattering (SAXS) data owing to the hardly accessible image characterization of the nanometric building blocks - micelle-like cylindrical polymeric aggregates (radius ~ 2 - 6 nm and length > 100 nm) [3]. Herein, broadband dielectric spectroscopy (BDS) measurements, free from electrode polarization effects, allowed identifying the time and temperature dependence of the polarization of different length scales of the ionomer matrix, and more importantly, by directly providing the aspect ratio of the radius and length of the polymeric aggregates for each desired temperature. This finding is essential for controlling the shape of ionomer based functional products under several stimuli conditions, thereby advancing remarkable applications, such as four dimensional (4D) printing and polymer electrolyte fuel cells.

    Palavras-Chave: building materials; relaxation; scattering; temperature dependence; electrolytic cells; spectroscopy

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  • IPEN-DOC 24776

    PEREIRA, LUIZ A.T. ; ROSSI, JESUALDO L. . The recycling through melting Zircaloy machining chips, preliminary results. Brazilian Journal of Radiation Sciences, v. 6, n. 2, p. 01-11, 2018. DOI: 10.15392/bjrs.v6i2.425

    Abstract: PWR (Pressurized Water Reactor) reactors employ as nuclear fuel UO2 pellets packed in zirconium alloy tubes, called cladding. In the manufacture of the tubes, machining chips are generated which can not be discarded, since the recycling of this material is strategic in terms of nuclear technology, legislation, economics and the environment. These nuclear alloys are very expensive and are not produced in Brazil and are imported for the manufacture of nuclear fuel. In this work, we will discuss methods not yet studied to recycle Zircaloy chips using electron beam furnaces in order to obtain ingots. In addition, it is intended to carry out the melting of new Zircaloy alloys, from the fusion of zirconium sponge produced in IPEN and imported and Zircaloy bars. The mechanical properties and the present phases of the material should be determined, as well as, the characterization of the microstructures by optical microscopy. This work, therefore, aims at the creation of a new line of research where methods will be approached to recycle the chips and to reduce in 30 times by means of fusion the enormous volume of material stored in the form of machining chips, being able to do others components for nuclear or chemical industry use, as well as conducting basic development research.

    Palavras-Chave: cladding; electron beam melting; heat treatments; mechanical properties; microstructure; nuclear fuels; optical microscopy; recycling; zircaloy

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  • IPEN-DOC 25074

    CARDOSO, QUEZIA ; SILVA, FRANKS M.; VIEIRA, LIGIA S.; CASINI, JULIO C.S.; SAKATA, SOLANGE K. ; FARIA, RUBENS N. de . The production of reduced graphene oxide by a low-cost vacuum system for supercapacitor applications. Materials Science Forum, v. 930, p. 609-612, 2018. DOI: 10.4028/www.scientific.net/MSF.930.609

    Abstract: Graphene has attracted significant interest because of its excellent electrical properties. However, a practical method for producing graphene on a large scale is yet to be developed. Graphene oxide (GO) can be partially reduced to graphene-like sheets by removing the oxygencontaining groups and recovering the conjugated structure. GO can be produced using inexpensive graphite as the raw material via cost-effective chemical methods. High vacuum and temperature (10−7 mbar and 1100°C, respectively) conditions are well-known to enable the preparation of reduced powder at the laboratory scale. However, a large-scale high vacuum reduction system that can be routinely operated at 10−7 mbar requires considerable initial capital as well as substantial operational and maintenance costs. The current study aims at developing an inexpensive method for the large-scale reduction of graphene oxide. A stainless steel vessel was evacuated to backing-pump pressure (10−2 mbar) and used to process GO at a range of temperatures. The reduction of GO powder at low vacuum pressures was attempted and investigated by X-ray diffraction and Fourier transform infrared spectroscopy. The experimental results of processing GO powder at various temperatures (200–1000°C) at relatively low pressures are reported. The microstructures of the processed materials were investigated using scanning electron microscopy and chemical microanalyses via energy dispersive X-ray analysis.

    Palavras-Chave: capacitors; fourier transformation; graphene; infrared spectra; microstructure; oxides; production; reduction; scanning electron microscopy; temperature dependence; x-ray diffraction

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  • IPEN-DOC 25475

    SHINZATO, M.C.; ALMEIDA, T.M.; GUEDES-SILVA, C.C. ; SILVA, E.F.S.. The potential use of the alkaline waste from the aluminum industry as aluminum and silicon source in the geopolymerization process. In: INTERNATIONAL CONGRESS ON CERAMICS, 7th; CONGRESSO BRASILEIRO DE CERÂMICA, 62., June 17-21, 2018, Foz do Iguaçu, PR. Abstract... 2018. p. 353-353.

    Abstract: The objective of this work was to evaluate the alkaline waste of the aluminum industry (red mud) as a source of aluminum and silicon in the production of geopolymers. These elements are essential to form the tetrahedrally coordinated structures of the geopolymers. The characteristics of the studied material were compared with those of metakaolinite, since the latter is considered an excellent geopolymer precursor material. Samples of the dehydrated red mud were supplied by a Brazilian primary aluminum industry. This material was chemically (X-ray fluorescence) and mineralogically (X-ray diffraction) characterized. Samples of metakaolinite and red mud (original and pretreated by heating at 700 oC/2 h) were subjected to a leaching test with a 12 mol L-1 NaOH solution to determine the contents of reactive silica and alumina fractions. The Si4+ and Al3+ contents of the filtered solutions were determined by plasma optical emission spectrometry. The red mud has a total of 21.7% Al2O3 and 16.6% SiO2, and it is composed by the mineral phases: quartz, hematite, kaolinite, goethite, gibbsite, anatase, sodalite, gypsum. The contents of the leached fractions of Al3+ and Si4+ of the original red mud were respectively 3.9% and 0.7%. The red mud heated sample presented higher contents of Al3+ (8.5%) and Si4+ (6.6%). It was verified that the heating process increased the concentrations of Al and Si fractions available for the geopolymerization reactions. These values are closer to those obtained for metakaolinite (9.2% Al3+ and 4.4 Si4+). The X-ray diffraction data of the heated red mud revealed that the hydroxylated phases became amorphous and promoted the formation of metakaolinite. Thus, the red mud has important components, which when heated, increase the Al and Si availability for the geopolymerization reactions. The other components of the red mud, being less reactive, serve as aggregates for the geopolymer composition.

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  • IPEN-DOC 25905

    CAVALCANTI, H. de S. ; MIURA, VIVIANI M. ; ZAMBONI, CIBELE B. ; SILVA, DALTON G.N. da ; AZEVEDO, MARIA R.. The potassium reference value in blood in inhabitants of Brazil using EDXRF technique. In: BRAZILIAN MEETING ON NUCLEAR PHYSICS, 41th, September 2-6, 2018, Maresias, SP. Abstract... São Paulo: Sociedade Brasileira de Física, 2018. p. 1-1.

    Abstract: In this investigation, we intend to determine potassium levels in human blood aiming to study in more details the common de¯ciencies in Brazilian population helping their diagnostic well as to facilitate the interpretation of data deriving from clinical practice. The potassium takes part in the human being metabolism and it is very important for preservation of the osmotic and acid-base equilibria of human °uids, so its variations are generally associated to pathological processes. The objective of this study is the establishment of reliable potassium reference value in blood, using EDXRF technique, with emphasis on the statistical treatment. The samples came from Blood Banks from di®erent parts of Brazil. The biological samples were obtained from a select healthy group (male and female blood donors), following the procedure conventionally establish for blood donation. The in°uence of sex and age was evaluated considering several range for age (18-20, 21-30, 31-40, 41-50, 3 51 years). The result is presented following a descriptive statistics procedure, which includes the evaluation of mean, standard deviation, median and mode. This statistical treatment make possible the comparison with data derived for di®erent population groups. These results show small di®erences when a comparison is performed in function of age and sex emphasizing the necessity to adopt ranges.

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  • IPEN-DOC 25124

    NASCIMENTO, C.R.; ASFORA, V.K.; GONCALVES, J.A.C. ; KHOURY, H.J.; BARROS, V.S.M.; KALIL, L.F.; BUENO, C.C. . The performance of a multi guard ring (MGR) diode for clinical electron beams dosimetry. Applied Radiation and Isotopes, v. 141, p. 112-117, 2018. DOI: 10.1016/j.apradiso.2018.07.002

    Abstract: The dosimetric response of a multi guard ring structure (MGR) diode has been studied with clinical electron beam energies from 5 MeV to 15 MeV. The results showed that the MGR dose response is linear in the range of 5–320 cGy and presents reproducibility with variation coefficients less than 0.4%. The field output factors measured with the MGR agreed within 2% with those measured with an ionization chamber. This study evidences that this diode can be used for clinical electron beam dosimetry.

    Palavras-Chave: electron beams; electron dosimetry; ionization chambers; mev range 01-10; mev range 10-100; rings; security personnel; semiconductor detectors; semiconductor materials

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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.

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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.

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.