Reposiório IPEN: Recent submissions

  • IPEN-DOC 25122

    NANDENHA, J. ; FONTES, E.H. ; PIASENTIN, R.M. ; FONSECA, F.C. ; NETO, A.O. . Direct oxidation of methane at low temperature using Pt/C, Pd/C, Pt/C-ATO and Pd/C-ATO electrocatalysts prepared by sodium borohydride reduction process. Journal of Fuel Chemistry and Technology, v. 46, n. 9, p. 1137-1145, 2018. DOI: 10.1016/S1872-5813(18)30046-X

    Abstract: The main objective of this paper was to characterize the voltammetric profiles of the Pt/C, Pt/C-ATO, Pd/C and Pd/C-ATO electrocatalysts and study their catalytic activities for methane oxidation in an acidic electrolyte at 25°C and in a direct methane proton exchange membrane fuel cell at 80°C. The electrocatalysts prepared also were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The diffractograms of the Pt/C and Pt/C-ATO electrocatalysts show four peaks associated with Pt face-centered cubic (fcc) structure, and the diffractograms of Pd/C and Pd/C-ATO show four peaks associated with Pd face-centered cubic (fcc) structure. For Pt/C-ATO and Pd/C-ATO, characteristic peaks of cassiterite (SnO2) phase are observed, which are associated with Sb-doped SnO2 (ATO) used as supports for electrocatalysts. Cyclic voltammograms (CV) of all electrocatalysts after adsorption of methane show that there is a current increase during the anodic scan. However, this effect is more pronounced for Pt/C-ATO and Pd/C-ATO. This process is related to the oxidation of the adsorbed species through the bifunctional mechanism, where ATO provides oxygenated species for the oxidation of CO or HCO intermediates adsorbed in Pt or Pd sites. From in situ ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared) experiments for all electrocatalysts prepared the formation of HCO or CO intermediates are observed, which indicates the production of carbon dioxide. Polarization curves at 80°C in a direct methane fuel cell (DMEFC) show that Pd/C and Pt/C electroacatalysts have superior performance to Pd/C-ATO and Pt/C-ATO in methane oxidation.

    Palavras-Chave: methane; oxidation; electrocatalysts; sodium; borohydrides; polarization; electrochemistry; palladium compounds; platinum compounds

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  • IPEN-DOC 25120

    MUTARELLI, RITA de C. ; LIMA, ANA C. de S. ; SABUNDJIAN, GAIANE . Comparative study of methodologies for measuring corporate social responsibility. International Journal of Development Research, v. 8, n. 6, p. 20894-20903, 2018.

    Abstract: The Corporate Social Responsibility (CSR) is a current issue increasingly present in the strategic planning of the companies. Although managers of public or private organizations have turned their attention to social and environmental issues in their strategic actions, measuring the social responsibility of a company is not an easy task. This paper aims to observe the eight most relevant methodologies of CSR measurement and establish a comparative analysis among them by considering the scope and feasibility of each methodology. The most relevant CSR methodologies were selected. The main characteristics of each of the eight tools were observed and compared. The results demonstrated that although most methodologies have strong measuring characteristics the Ethos Indicators consist of the most effective tool for measuring CSR mainly regarding the institutional issues

    Palavras-Chave: management; socio-economic factors; institutional factors; sustainability; resource management; social impact; environmental policy; environmental protection; cooperation; ecosystems; ecology; economic impact

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  • IPEN-DOC 25119

    MURATA, H.M.; MORALLES, M. ; BONIFACIO, D.A.B.. Evaluation of digital methods for energy calculation and timing pick-off in positron emission tomography. Journal of Instrumentation, v. 13, n. P09024, 2018. DOI: 10.1088/1748-0221/13/09/P09024

    Abstract: Traditionally, pulse processing in Positron Emission Tomography (PET) has been based on analog or discrete circuits forming a decentralized processing system. However, there is a convergence for digital and integrated implementations due to the characteristics of the modern electronic devices which are real-time processing capable, such as Application-Specific Integrated Circuit (ASIC) and Field Programmable Gate Array (FPGA) with fast Analog to Digital Converters (ADC). However, FPGA can provide fast implementation at relatively low cost and also enables the development of sophisticated digital pulse processing algorithms to improve energy, position and time resolutions in PET systems. Our group has developed and evaluated one energy calculation and three timing pick-off methods for implementation onto an FPGA-based system. For a typical PET detector setup, our charge integration method presents energy resolution similar to previously designed PET detectors. The best performance for timing pick-off was achieved by the Initial Rise Interpolation (IRI) method, where a coincidence time resolution of around 440 ps is suitable for Time of Flight (TOF) PET. Future works include embedding the proposed algorithms in a FPGAbased data acquisition system under development by our group which will be employed in a PET prototype.

    Palavras-Chave: algorithms; analog-to-digital converters; data acquisition systems; design; energy resolution; evaluation; positron computed tomography; time resolution; time-of-flight method

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  • IPEN-DOC 25118

    MUCSI, C.S. ; REIS, L.A.M. dos ; GOMES, M.P. ; PEREIRA, L.A.T. ; ROSSI, J.L. . Study on the viability of the recycling by electric arc melting of zirconium alloys scraps aiming the scalability of the process. Materials Science Forum, v. 930, p. 495-500, 2018. DOI: 10.4028/www.scientific.net/MSF.930.495

    Abstract: Turning chips of zirconium alloys are produced in large quantities during the machining of alloy rods for the fabrication of the end plugs for the Pressurized Water Reactor (PWR) fuel elements parts of Angra II nuclear reactor (Brazil – Rio de Janeiro). This paper presents a study on the search for an efficient way for the cleaning, quality control and Vacuum Arc Remelting (VAR) of pressed zirconium alloys chips to produce a material viable to be used in the production of the fuel rod end plugs. The process starts with cutting oil clean out. The first step in this process consists in soaking a bunch of chips in clean water, to remove soluble cutting oils, followed by an alkaline degreasing bath and a wash with a high-pressure flow of water. Drying is performed by a flux of warm air. The oil free chips are then subjected to a magnet in order to detect and collect any magnetic material, essentially ferrous, that may be present in the original chips. Samples of the material are collected and then melted in a small non consumable electrode vacuum arc furnace for evaluation by Energy Dispersive X-ray Fluorescence Spectrometry (EDXRFS) in order to define the quality of the chips. The next step consists in the 15 ton hydraulic pressing the chips in a die with 40 mm square section and 500 mm long, producing an electrode with 20% of the Zircaloy bulk density. The electrode was finally melted in a laboratory scale modified VAR furnace located at the CCTM–IPEN, producing 0.8 kg ingots. The authors conclude that the samples obtained from the fuel element industry can be melting in a VAR furnace, modified to accommodate low density electrodes, allowing a reduction up to 40 times the original storage volume, however, it is necessary to remelt the ingots to correct their composition in order to recycle the original zirconium alloys chips. in a process to reduce volume and allow the reutilization of valuable Zircaloy scraps.

    Palavras-Chave: zirconium alloys; recycling; melting; pwr type reactors; vacuum melting; fuel elements; fluorescence spectroscopy; x-ray sources; angra-2 reactor; electric arcs

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  • IPEN-DOC 25117

    MUCCILLO, R. ; ESPOSITO, V.; FLORIO, D.Z. de; MUCCILLO, E.N.S. . Electric field-assisted pressureless sintering gadolinium-, yttrium- and samarium-doped barium cerate. Scripta Materialia, v. 156, p. 6-9, 2018. DOI: 10.1016/j.scriptamat.2018.07.005

    Abstract: Gadolinium-, yttrium- and samarium-doped barium cerate compounds were sintered either conventionally at 1500 °C or applying an electric field at 1200 °C. The combined results of dilatometry and impedance spectroscopy measurements in electric field-assisted sintered specimens show substantial improvement of the electrical conductivity. Improved grain-to-grain contact and the thermal removal of depleted chemical species due to Joule heating at the space charge region are proposed as the main mechanisms for the increase of both the grain boundary and the bulk electrical conductivities, respectively.

    Palavras-Chave: barium; dilatometry; doped materials; electric conductivity; electric fields; gadolinium; grain boundaries; impedance; joule heating; samarium; sintering; space charge; spectroscopy; yttrium

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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 25115

    MOREIRA, GREGORI de A. ; GUERRERO-RASCADO, JUAN L.; BRAVO-ARANDA, JUAN A.; BENAVENT-OLTRA, JOSE A.; ORTIZ-AMEZCUA, PABLO; ROMAN, ROBERTO; BEDOYA-VELASQUEZ, ANDRES E.; LANDULFO, EDUARDO ; ALADOS-ARBOLEDAS, LUCAS. Study of the planetary boundary layer by microwave radiometer, elastic lidar and Doppler lidar estimations in Southern Iberian Peninsula. Atmospheric Research, v. 213, p. 185-195, 2018. DOI: 10.1016/j.atmosres.2018.06.007

    Abstract: The Planetary Boundary Layer (PBL) is a relevant part of the atmosphere with a variable extension that clearly plays an important role in fields like air quality or weather forecasting. Passive and active remote sensing systems have been widely applied to analyze PBL characteristics. The combination of different remote sensing techniques allows obtaining a complete picture on the PBL dynamic. In this study, we analyze the PBL using microwave radiometer, elastic lidar and Doppler lidar data. We use co-located data simultaneously gathered in the framework of SLOPE-I (Sierra Nevada Lidar aerOsol Profiling Experiment) campaign at Granada (Spain) during a 90- day period in summer 2016. Firstly, the PBL height (PBLH) obtained from microwave radiometer data is validated against PBLH provided by analyzing co-located radiosondes, showing a good agreement. In a second stage, active remote sensing systems are used for deriving the PBLH. Thus, an extended Kalman filter method is applied to data obtained by the elastic lidar while the vertical wind speed variance method is applied to the Doppler lidar. PBLH′s derived by these approaches are compared to PBLH retrieved by the microwave radiometer. The results show a good agreement among these retrievals based on active remote sensing in most of the cases, although some discrepancies appear in instances of intense PBL changes (either growth and/or decrease).

    Palavras-Chave: planetary atmospheres; optical radar; doppler effect; spain; microwave radiation; radiometers; troposphere; dusts; meteorology

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  • IPEN-DOC 25114

    MATOS, BRUNO R. ; POLITANO, RODOLFO ; REY, JOSE F.Q.; HERMIDA-MERINO, DANIEL; SCHADE, ULRICH; PUSKAR, LJILJANA; FONSECA, FABIO C. . Interplay of alpha/beta-relaxation dynamics and the shape of ionomer building blocks. Scientific Reports, v. 8, n. 13441, 2018. DOI: 10.1038/s41598-018-31368-8

    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 temperature-dependent property: the memory of shape. 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 similar to 2-6 nm and length >100 nm). 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.

    Palavras-Chave: polymers; simulation; morphological changes; small angle scattering; relaxation; x radiation

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  • IPEN-DOC 25113

    MARTINS, JOAO F.T. ; SANTOS, ROBINSON A. dos ; FERRAZ, CAUE de M. ; OLIVEIRA, RENE R. ; FIEDERLE, MICHAEL; AMADEU, RAFAEL de A. ; SANTOS, RODRIGO S. dos ; SILVA, THIAGO L.B. da ; HAMADA, MARGARIDA M. . Optimization of the HgI2 Crystal preparation for application as a radiation semiconductor detector. Studies in Engineering and Technology, v. 5, n. 1, p. 76-88, 2018. DOI: 10.11114/set.v5i1.3149

    Abstract: The effect of HgI2 crystal encapsulation using different polymer resins, with the intent of avoiding the oxidation of the crystal surface, was evaluated in this work. The crystal was purified and grown by the physical vapor transport (PVT) technique modified. Systematic measurements were carried out for evaluating the stoichiometry, structure orientation, surface morphology and impurity of the crystal grown. The purer region of the crystal grown was selected to be prepared as a radiation detector, applying water-based conductive ink contacts and copper wire on the crystal surfaces. After that, the crystal was encapsulated with a polymeric resin which insulates atmospheric gases, aiming to improve the stability of the HgI2 detector. Four resins were used for crystal encapslation and the performance of the detector depended on the composition of the resins used. Among the four resins studied to evaluate the influence of encapsulation on the performance of crystals, as a radiation detector, the best result of resistivity and energy spectrum was obtained for the resin #3 (50% - 100% of Methylacetate and 5% - 10% of n-butylacetate). The encapsulation of crystals with polymer resins, performed with the intent of avoiding the oxidation of the crystal surface, did not compromise the measurements and were fully capable of detecting the presence of gamma radiation. The stability of the encapsulated HgI2 crystal detector was of up to 78 hs, while the stability found for HgI2 detector no encapsulated was in order 3 ~4 hs.

    Palavras-Chave: radiation detectors; semiconductor materials; crystals; surfaces; morphology; resins; polymers; mercury iodides; crystal structure

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  • IPEN-DOC 25112

    MARIANO, DOUGLAS O.C.; MESSIAS, MARCELA Di G. ; PREZOTTO-NETO, JOSE P. ; SPENCER, PATRICK J. ; PIMENTA, DANIEL C.. Biochemical analyses of proteins from duttaphrynus melanostictus (Bufo melanostictus) skin secretion: soluble protein retrieval from a viscous matrix by ion-exchange batch sample preparation. Protein Journal, v. 37, n. 4, p. 380-389, 2018. DOI: 10.1007/s10930-018-9780-z

    Abstract: A crucial step in scientific analysis can be sample preparation, and its importance increases in the same rate as the sensitivity of the following employed/desired analytical technique does. The need to analyze complex, viscous matrices is not new, and diverse approaches have been employed, with different success rates depending on the intended molecules. Solid-phase extraction, for example, has been successfully used in sample preparation for organic molecules and peptides. However, due to the usual methodological conditions, biologically active proteins are not successfully retrieved by this technique, resulting in a low rate of protein identification reported for the viscous amphibian skin secretion. Here we describe an ion-exchange batch processing sample preparation technique that allows viscous or adhesive materials (as some amphibian skin secretions) to be further processed by classical liquid chromatography approaches. According to our protocol, samples were allowed to equilibrate with a specific resin that was washed with appropriated buffers in order to yield the soluble protein fraction. In order to show the efficiency of our methodology, we have compared our results to classically prepared skin secretion, i.e., by means of filtration and centrifugation. After batch sample preparation, we were able to obtain reproductive resolved protein chromatographic profiles, as revealed by SDS-PAGE, and retrieve some biological activities, namely, hydrolases belonging to serine peptidase family. Not only that, but also the unbound fraction was rich in low molecular mass molecules, such as alkaloids and steroids, making this sample preparation technique also suitable for the enrichment of such molecules.

    Palavras-Chave: chromatography; ion exchange chromatography; animal tissues; secretion; skin; sample preparation; viscosity; amphibians; hydrolases

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  • IPEN-DOC 25110

    UCO, DAYANE P.; LEITE-SILVA, VANIA R.; SILVA, HERON D.T.; DUQUE, MARCELO D.; GRICE, JEFFREY; MATHOR, MONICA B. ; ANDREO-FILHO, NEWTON; LOPES, PATRICIA S.. UVA and UVB formulation phototoxicity in a three-dimensional human skin model: photodegradation effect. Toxicology in Vitro, v. 53, p. 37-44, 2018. DOI: 10.1016/j.tiv.2018.07.009

    Abstract: In vitro three-dimensional human skin models are an innovative alternative to evaluate cytotoxicity and phototoxicity in the cosmetic industry. The aim of this study was to use a skin model to evaluate the potential toxicity of sunscreen formulations with or without exposure to UV radiation. In addition, the toxicity of these formulations was evaluated after exposure to photodegradation. The results showed toxicity with all formulations/conditions tested, including the control formulation, compared to PBS. Cell viability of photodegraded formulations - prior to the phototoxicity radiation process - was higher, indicating that some formulation components were degraded into products with reduced toxicity. The results also indicated that avobenzone was more unstable/toxic than octyl p-methoxycinnamate under the same test conditions. The sunscreens and their formulations were shown to be toxic to skin model cells to some extent, even when not exposed to UV irradiation; however the biological role of this toxicity is unclear. This result shows the importance of testing sunscreen formulations in real in-use conditions. Finally, since we used an in vitro assay based on a human cell model, this non-invasive technique represents a suitable alternative to animal models for phototoxicity tests in general and could have application in screening new sunscreen products.

    Palavras-Chave: ultraviolet radiation; toxicity; spectrophotometry; three-dimensional calculations; skin; epidermis; animal cells; photoreactivation; radiolysis; epitheliomas; solar radiation

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  • IPEN-DOC 25109

    LEAL, GEORGIA B. ; CIOTTI, LIGIA ; WATACABE, BEATRIZ N. ; SILVA, DANIELA C.L. da ; ANTONIASSI, RODOLFO M. ; SILVA, JULIO C.M. ; LINARDI, MARCELO ; GIUDICI, REINALDO; VAZ, JORGE M. ; SPINACE, ESTEVAM V. . Preparation of Au/TiO2 by a facile method at room temperature for the CO preferential oxidation reaction. Catalysis Communications, v. 116, p. 38-42, 2018. DOI: 10.1016/j.catcom.2018.07.021

    Abstract: A simple strategy was used to prepare Au/TiO2 catalyst at room temperature. Au nanoparticles were initially prepared in solution using HAuCl4.3H2O as Au precursor, sodium citrate as stabilizing agent and sodium borohydride as reducing agent. The preformed Au nanoparticles were further supported on TiO2 and the resulting solid material was characterized by Energy-dispersive X-ray spectroscopy, X-ray diffraction and Transmission Electron Microscopy and tested for the preferential oxidation of carbon monoxide in hydrogen-rich stream (COPROX reaction). The obtained Au/TiO2 catalyst consisted of Au nanoparticles with an average size of ~ 4 nm and showed excellent catalytic performance in the 20-50 °C low-temperature range. In particular, at 40 °C a CO conversion of 99.5% and CO2 selectivity of 45% were obtained using an O2/CO ratio of 2 (1 vol% CO, λ=4) and 97 vol% H2 in the feed gas stream (GHSV=15,000 mL gcat −1 h−1).

    Palavras-Chave: gold ions; titanium oxides; oxidation; carbon monoxide; nanoparticles; carbon monoxide; ambient temperature; hydrogen

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  • IPEN-DOC 25108

    LARROZA, ELIANE G. ; KECKHUT, PHILIPPE; BARAY, JEAN-LUC; NAKAEMA, WALTER M.; VEREMES, HELENE; LANDULFO, EDUARDO ; DIONISI, DAVIDE; KHAYKIN, SERGEY; RAVETTA, FRANCOIS. Long-range transport of water channelized through the southern subtropical jet. Atmosphere, v. 9, n. 10, 2018. DOI: 10.3390/atmos9100374

    Abstract: In this study, an air mass (containing a cirrus cloud) was detected by light detection and ranging (lidar) above São Paulo (Brazil) in June 2007 and tracked around the globe, thanks to Lagrangian calculations as well as ground-based and satellite observations. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data were also used to provide locations of occurrence of cirrus around the globe and extract their respective macro physical parameters (altitude and temperature). An analysis of the air mass history based on Lagrangian trajectories reveals that water coming from the Equator is channelized through the southern subtropical jet for weeks. In this case, the back-trajectories showed that the cirrus cloud detected at São Paulo was a mixture of air masses from two different locations: (1) the active convective area located around the Equator, with transport into the upper troposphere that promotes cirrus cloud formation; and (2) the South Pacific Ocean, with transport that follows the subtropical jet stream (STJ). Air masses coming from equatorial convective regions are trapped by the jet, which contributes to maintaining the lifetime of the cirrus cloud for a few days. The cloud disappears near the African continent, due to a southern excursion and warmer temperatures, then reappears and is detected again by the lidar system in São Paulo after 12 days. The observed cloud is located at a similar altitude, revealing that sedimentation is small or compensated by radiative uplift.

    Palavras-Chave: clouds; aerosols; atmospheres; optical radar; lagrangian function; satellite atmospheres; stratosphere; rayleigh scattering; brazil; water vapor

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  • IPEN-DOC 25106

    KAFER, KARINE A.; BERNARDI, HEIDE H.; SANTOS, OSMAR de S.; OTUBO, LARISSA ; LIMA, NELSON B. de ; OTUBO, JORGE. The influence of microstructure and mechanical resistance on the shape memory of ECAE processed stainless Fe-Mn-Si-Cr-Ni-Co steel. Materials Research, v. 21, n. 5, 2018. DOI: 10.1590/1980-5373-MR-2017-0958

    Abstract: In the current work, XRD, SEM, EBSD and TEM techniques were used to evaluate the microstructure of stainless Fe-Mn-Si-Cr-Ni-Co shape memory steel processed by ECAE and annealed for one hour at temperatures ranging from 650ºC to 950ºC. The results were then correlated with the mechanical and shape-memory properties of the steel. It was observed that the samples containing large grains and a microstructure free of defects or precipitates presented a high volume fraction of multi-variant thermal martensite and stress-induced martensite, resulting in good shape recovery, owing to the memory effect. The grain refinement and precipitation of second-phase particles decreased the volume fraction and number of martensite variants and considerably increased the mechanical resistance, enhancing the elastic shape recovery. It was shown that shape memory properties were essentially related to the mechanical resistance of the matrix, which in turn was related to the microstructure.

    Palavras-Chave: backscattering; grain size; martensite; mechanical properties; microstructure; scanning electron microscopy; shape memory effect; stainless steels; transmission electron microscopy; x-ray diffraction

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  • IPEN-DOC 25105

    SOUZA, SAMIRA H.J.; MACHADO, ALANA C.; LOPES, RAQUEL M.; ZEZELL, DENISE M. ; SCARAMUCCI, TAIS; ARANHA, ANA C.C.. Effectiveness and acid/tooth brushing resistance of in-office desensitizing treatments - a hydraulic conductance study. Archives of Oral Biology, v. 96, p. 130-136, 2018. DOI: 10.1016/j.archoralbio.2018.09.004

    Abstract: Objective: To evaluate dentin permeability and tubule occlusion of in-office desensitizing treatments, and to analyze their resistance to erosive/abrasive challenges. Design: Ninety-one 1mm-thick dentin discs were immersed in EDTA solution for 5 min. After analyzing the maximum dentin permeability, the specimens were randomly allocated into 7 experimental groups (n=10): Control (no treatment); Er,Cr:YSGG laser; Nd:YAG laser; Gluma Desensitizer; Duraphat; Pro-Argin toothpaste; Calcium Sodium Phosphosilicate (CSP) paste. The post-treatment permeability was assessed and then the specimens were subjected to a 5-day erosion-abrasion cycling protocol: 4x/day of immersion in citric acid solution (5 min;0.3%), followed by exposure to clarified human saliva (60 min). After the first and last acid challenges, specimens were brushed for 15 s, with exposure to the toothpaste slurry for total time of 2 min. Dentin permeability was re-measured (post-cycling). Percentage of dentin permeability for each experimental time was calculated in relation to the maximum permeability (%Lp). Data were analyzed with 2-way repeated measures ANOVA and Tukey tests (α=0.05). Surface modifications were analyzed by scanning electron microscopy. Results: In both experimental time CSP paste and Gluma Desensitizer did not differ from each other (p=0.0874), and were the only groups that presented significantly lower %Lp than the Control (p=0.026 and p=0.022, respectively). After treatment, they were able to reduce dentin permeability in 82% and 72%, respectively. The %Lp post-cycling was higher than post-treatment value for all groups (p=0.008). Dentin permeability increased 21% for CSP paste and 12% for Gluma, but they remained significant different from Control. Deposits on the surface were observed for CSP paste; and for Gluma, tubule diameters were shown to be smaller. Conclusions: CSP paste and Gluma Desensitizer were the only treatments able to decrease dentin permeability post-treatment and to sustain low permeability post-cycling.

    Palavras-Chave: dentistry; dentin; permeability; sample preparation; erosion; abrasion; calcium; sodium; teeth

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  • IPEN-DOC 25104

    JIMENEZ-VILLAR, ERNESTO ; XAVIER, M.C.S.; WETTER, NIKLAUS U. ; MESTRE, VALDECI; MARTINS, WELITON S.; BASSO, GABRIEL F.; ERMAKOV, V.A.; MARQUES, F.C.; SA, GILBERTO F. de. Anomalous transport of light at the phase transition to localization: strong dependence with incident angle. Photonics Research, v. 6, n. 10, p. 929-942, 2018. DOI: 10.1364/PRJ.6.000929

    Abstract: There has been a growing interest in disordered optical media in recent years due to their potential applications in solar collectors, random lasers, light confinement, and other advanced photonic functions. This paper studies the transport of light for different incidence angles in a strongly disordered optical medium composed of core-shell TiO2@Silica nanoparticles suspended in an ethanol solution. A decrease of optical conductance and an increase of absorption near the input border are reported when the incidence angle increases. The specular reflection, measured for the photons that enter the sample, is lower than the effective internal reflection undergone by the coherently backscattered photons in the exact opposite direction, indicating a nonreciprocal propagation of light. This study represents a novel approach in order to understand the complex physics involved at the phase transition to localization.

    Palavras-Chave: backscattering; titanium oxides; silica; optical properties; light transmission; quantum electrodynamics; nanomaterials; multiple scattering; light sources

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  • IPEN-DOC 25103

    ICHIKAWA, R.U. ; LINHARES, H.S.M.D.; PERAL, I.; BALDOCHI, S.L. ; RANIERI, I.M. ; TURRILLAS, X.; MARTINEZ, L.G. . Evidence for a core–shell configuration in Tb-doped KY3F10 nanoparticles using synchrotron x-ray line profile and pair distribution function analyses. Materials Research Express, v. 5, n. 1, 2018. DOI: 10.1088/2053-1591/aaa0bc

    Abstract: The microstructure of Tb-doped KY3F10 nanoparticles synthesized by coprecipitation was analysed using x-ray synchrotron diffraction data. Size-strain analysis was performed by means of x-ray line profile (XLPA) methods such as Warren–Averbach and whole powder pattern modelling. Additionally, the structural coherence of the sample was accessed using pair distribution function analysis, supporting the XLPA results. The combination of all methods revealed that the nanoparticles exhibit a more ordered core and a less ordered surface comprising a core–shell configuration.

    Palavras-Chave: nanoparticles; terbium; doped materials; x-ray diffraction; pair production; pairing interactions; distribution functions; yttrium fluorides; configuration; shell models

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  • IPEN-DOC 25102

    HAZENFRATZ, R. ; MUNITA, C.S. ; NEVES, E.G.. Neural networks (SOM) applied to INAA data of chemical elements in archaeological ceramics from Central Amazon. Science & Technology of Archaeological Research, v. 3, n. 2, SI, p. 334-340, 2018. DOI: 10.1080/20548923.2018.1470218

    Abstract: Artificial neural networks represent an alternative to traditional multivariate techniques, such as principal component and discriminant analysis, which rely on hypotheses regarding the normal distribution of the data and homoscedasticity. They also may be a powerful tool for multivariate modeling of systems that do not present linear correlation between variables, as well as to visualize high-dimensional data in bi- or trivariate structures. One special kind of neural network of interest in archaeometric studies is the Self-Organizing Map (SOM). SOMs can be distinguished from other neural networks for preserving the topological features of the original multivariate space. in this study, the self-organizing maps were applied to concentration data of chemical elements measured in archaeological ceramics from Central Amazon using instrumental neutron activation analysis (INAA). The main objective was testing the chemical patterns previously identified using cluster and principal component analysis, forming groups of ceramics according the multivariate chemical composition. It was verified by statistical tests that the chemical elemental data was not normally distributed and did not present homogeneity of covariance matrices for different groups, as requested by principal component analysis and other multivariate techniques. The maps obtained were consistent with the patterns identified by cluster and principal component analysis, forming two chemical groups of pottery shards for each archaeological site tested. Finally, it was verified the potential of SOMs for testing if failures in underlying hypotheses of traditional multivariate techniques might be critically influencing the results and subsequent archaeological interpretation of archaeometric data.

    Palavras-Chave: neural networks; neutron activation analysis; elements; archaeological specimens; ceramics; archaeological sites; archaeology; concentration

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  • IPEN-DOC 25100

    GUEDES-SILVA, CECILIA C. ; RODAS, ANDREA C.D.; SILVA, ANTONIO C. ; RIBEIRO, CHRISTIANE; CARVALHO, FLAVIO M. de S.; HIGA, OLGA Z. ; FERREIRA, THIAGO dos S. . Microstructure, mechanical properties and in vitro biological behavior of silicon nitride ceramics. Materials Research, v. 21, n. 6, 2018. DOI: 10.1590/1980-5373-MR-2018-0266

    Abstract: The bioinert surface of silicon nitride ceramics led us to investigate the additions of SiO2, CaO and Al2O3 in order to aid the liquid phase sintering and improve the mechanical properties and biological behavior of the final materials. The sintered materials reached ca. 97% of theoretical density and total α→β-Si3N4 transformation. The samples had relatively high values of fracture toughness while their elastic modulus values were lower than those of conventional silicon nitride ceramics. Apatite deposits were observed on the surfaces analyzed after SBF (simulated body fluid) immersions, suggesting their bioactivity. Osteoblasts proliferation and calcified matrix were also detected as response to cells/ materials contact. This combination of properties suggests that all studied compositions are promising for applications in biomedical devices. Moreover, compositions with alumina additions and higher silica content had better in vitro biological behavior, densification and mechanical properties, suggesting greater potential to be used in bone substitute devices.

    Palavras-Chave: ceramics; sintering; in vitro; mechanical properties; silicon nitrides; biological effects; apatites; deposits; body fluids; cell proliferation; tumor cells; connective tissue cells

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  • IPEN-DOC 25099

    GUALTEROS, JESUS A.D.; GARCIA, MARCO A.S.; SILVA, ANDERSON G.M. da; RODRIGUES, THENNER S. ; CANDIDO, EDUARDO G. ; SILVA, FELIPE A. e ; FONSECA, FABIO C. ; QUIROZ, JHON; OLIVEIRA, DANIELA C. de; TORRESI, SUSANA I.C. de; MOURA, CARLA V.R. de; CAMARGO, PEDRO H.C.; MOURA, EDMILSON M. de. Synthesis of highly dispersed gold nanoparticles on Al2O3, SiO2, and TiO2 for the solvent-free oxidation of benzyl alcohol under low metal loadings. Journal of Materials Science, v. 54, n. 1, p. 238-251, 2019. DOI: 10.1007/s10853-018-2827-x

    Abstract: We reported the organic template-free synthesis of gold (Au) nanoparticles (NPs) supported on TiO2, SiO2, and Al2O3 displaying uniform Au sizes and high dispersions over the supports. The Au-based catalysts were prepared by a deposition– precipitation method using urea as the precipitating agent. In the next step, the solvent-free oxidation of benzyl alcohol was investigated as model reaction using only 0.08–0.05 mol% of Au loadings and oxygen (O2) as the oxidant. Very high catalytic performances (TOF up to 443,624 h-1) could be achieved. Specifically, we investigated their catalytic activities, selectivity, and stabilities as well as the role of metal–support interactions over the performances. The conversion of the substrate was found to be associated with the nature of the employed support as the Au NPs presented similar sizes in all materials. A sub-stoichiometric amount of base was sufficient for the catalyst activation and the observation of the catalysts profile over the time enable insights on their recyclability performances. We believe this reported method represents a facile approach for the synthesis of uniform Au-supported catalysts displaying high performances.

    Palavras-Chave: synthesis; nanoparticles; oxidation; oxidizers; titanium oxides; silica; aluminium oxides; benzyl alcohol; catalysts; dispersions; gold

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  • IPEN-DOC 25098

    GONSALVES, TAYARA C. ; SILVA, FRANKS M.; VIEIRA, LIGIA S.; CASINI, JULIO C.S.; FARIA, RUBENS N. de . Electrochemical characteristics and microstructures of activated carbon powder supercapacitors for energy storage. Materials Science Forum, v. 930, p. 597-602, 2018. DOI: 10.4028/www.scientific.net/MSF.930.597

    Abstract: In recent years, extensive investigations have focused on the study and improvement of supercapacitor electrode materials. The electric devices produced with these materials are used to store energy over time periods ranging from seconds to several days. The main factor that determines the energy storage period of a supercapacitor is its self-discharge rate, i.e., the gradual decrease in electric potential that occurs when the supercapacitor terminals are not connected to either a charging circuit or electric load. Self-discharge is attenuated at lower temperatures, resulting in an increased energy storage period. This paper addresses the temperature-dependence of self-discharge via a systematic study of supercapacitors with nominal capacitances of 1.0 and 10.0 F at DC potentials of 5.5 and 2.7 V, respectively. The specific capacitances, internal resistances, and self-discharge characteristics of commercial activated carbon electrode supercapacitors were investigated. Using cyclic voltammetry, the specific capacitances were determined to be 44.4 and 66.7 Fg−1 for distinct carbon electrode supercapacitors. The self-discharge characteristics were investigated at both room temperature and close to the freezing point. The internal resistances of the supercapacitors were calculated using the discharge curves at room temperature. The microstructures of the electrode materials were determined using scanning electron microscopy.

    Palavras-Chave: activated carbon; capacitance; capacitors; electric discharges; electrodes; energy storage; microstructure; powders; scanning electron microscopy; voltametry; x-ray sources

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  • IPEN-DOC 25097

    GONCALVES, KARINA de O.; VIEIRA, DANIEL P. ; COURROL, LILIA C.. Study of THP-1 macrophage viability after sonodynamic therapy using methyl ester of 5-aminolevulinic acid gold nanoparticles. Ultrasound in Medicine & Biology, v. 44, n. 9, p. 2009-2017, 2018. DOI: 10.1016/j.ultrasmedbio.2018.05.012

    Abstract: Sonodynamic therapy (SDT) is emerging as new atherosclerosis treatment. The use of gold nanoparticles (AuNPs) as the vehicle for a sensitizer delivery improves reactive oxygen species formation. In this study, methyl ester of aminolevulinic acid (MALA) gold nanoparticles (MALA:AuNPs) functionalized with polyethylene glycol (PEG) were synthesized by photoreduction and characterized by ultraviolet/visible optical absorption, zeta potential and electron microscopy. The reactive oxygen species generation induced by ultrasound irradiation of MALA:AuNPs solutions was studied by observing the decrease in the 1,3-diphenylisobenzofuran emission band. The potential use of MALA:AuNPs as sensitizer for sonodynamic therapy was investigated on THP-1 macrophages. The cytotoxicity test was also described. The findings suggested that ultrasound combined with MALA:AuNPs provides impressive results in in vitro studies. Sonodynamic therapy with MALA:AuNPs through 2 minutes of ultrasound exposure (1 MHz and 1 W/cm2) culminated with total macrophage reduction. Thus, sonodynamic therapy combined with MALA:AuNPs has potential as a treatment for atherosclerosis.

    Palavras-Chave: macrophages; gold; nanoparticles; aminolevulinic acid; arteriosclerosis; therapy; tumor cells

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  • IPEN-DOC 25096

    GOMES, MAURILIO P. ; SANTOS, IGOR P. dos ; COUTO, CAMILA P. ; BETINI, EVANDRO G. ; REIS, LUIS A.M. dos ; MUCSI, CRISTIANO S. ; COLOSIO, MARCO A.; ROSSI, JESUALDO L. . Heat treatment of sintered valve seat inserts. Materials Research, v. 21, n. 5, 2018. DOI: 10.1590/1980-5373-MR-2018-0068

    Abstract: The characterization of sintered valve seat inserts (VSIs) after being subjected to different heat treatment operations has been carried out. The VSIs were obtained from three different alloys by mixing iron powder with AISI M3:2, AISI M2 high-speed steels, and AISI D2 tool steel. After sintering, the VSI were quenched in air followed by double tempering at seven different temperatures. The cooling rate during air quenching was measured by means of a thermocouple type k attached to a data acquisition system. The characterization of the mechanical and physical properties of the VSIs was achieved by measuring relative density, apparent hardness and crush radial strength. The resulting microstructures for the sintered parts were interpreted using the isothermal and continuous cooling transformation diagrams for similar alloys. The VSI obtained with AISI M3:2 and AISI M2 high-speed steels after air quenching and double tempering at 600 ºC showed the best results in terms of apparent hardness and crush radial strength.

    Palavras-Chave: powder metallurgy; sintering; heat treatments; valves; steels

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  • IPEN-DOC 25095

    GENARO, ISABELLA S. de; ALMEIDA, FRANCINE M. de; HIZUME-KUNZLER, DEBORAH C.; MORIYA, HENRIQUE T.; SILVA, RONALDO A.; CRUZ, JOAO C.G.; LOPES, RENAN B.; RIGHETTI, RENATO F.; VIEIRA, RODOLFO de P.; SAIKI, MITIKO ; MARTINS, MILTON A.; TIBERIO, IOLANDA de F.L.C.; ARANTES-COSTA, FERNANDA M.; SARAIVA-ROMANHOLO, BEATRIZ M.. Low dose of chlorine exposure exacerbates nasal and pulmonary allergic inflammation in mice. Scientific Reports, v. 8, n. 12636, 2018. DOI: 10.1038/s41598-018-30851-6

    Observação: Author Correction anexado. Scientific Reports, v. 8, p. 1, 2018. DOI: 10.1038/s41598-018-36667-8

    Abstract: Work-exacerbated asthma (WEA) is defined as preexisting asthma that worsens with exposure to irritants [e.g., chlorine (Cl2) derivatives] in the workplace. The maximum allowable concentration in the workplace of Cl2 exposure is 3 mg/ m3 (described in OSHA). We investigated in an experimental asthma model in mice the effects of a single exposure to a sodium hypochlorite dose with this allowed chlorine concentration and a tenfold higher dose. Acute chlorine exposure at 3.3 mg/m3 in the OVA-sensitized group increased eosinophils in the peribronquial infiltrate, cytokine production, nasal mucus production and the number of iNOS positive cells in the distal lung compared to only sensitized mice. The exposure to a higher dose of 33.3 mg/m3 in the OVA-sensitized group resulted in an increase in respiratory system elastance, in the total and differential numbers of inflammatory cells in bronchoalveolar lavage fluid, IL-4, IL-5, and IL-17 in the lungs, eosinophils in peribronquial infiltrate and mucus content in nasal compared to non-exposed and sensitized animals. In this asthma model, chorine exposures at an allowable dose, contributed to the potentiation of Th2 responses. The functional alterations were associated with increased iNOS and ROCK-2 activation in the distal lung.

    Palavras-Chave: chlorine; allergy; inflammation; lymphokines; nose; sinuses; respiratory system diseases; asthma

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  • IPEN-DOC 25094

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de ; MONTERRAIN, DANIEL. A system status definition to improve behavior description in specifications based on constructal law. Open Journal of Applied Sciences, v. 8, n. 8, p. 315-337, 2018. DOI: 10.4236/ojapps.2018.88024

    Abstract: System behavior description using states faces problems like state explosion, lack of clear definition of state, state identification and coordination between multiple agents. The goals of this work are to ease design activity, to reduce engineering efforts, and to mitigate project risks. The proposed way is to improve information flow during design by adding definitions and some protocols or rules for communicating a specification or design description. This work presented an objective definition of system status (way of interaction with the rest of the world) along other concepts. This work focused in definitions as mind entities and their importance to rationalize work and mitigate project risks during design. This article presented some simple examples to illustrate the advantages of each aspect of proposed definition of system status and discussed limits and exceptions for such definition. The key finding was the proposed definition which was the simplest while keeping completeness at a given product breakdown level. Such definition of status enforced formal segregation of needs and solutions, and eased the inclusion of behavior definition in specifications.

    Palavras-Chave: behavior; cooling systems; machining; control systems; systems analysis; engineering; automation; management; control systems; specifications; laws

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  • IPEN-DOC 25093

    FERREIRA, JOAO C. ; CAVALLARI, ROGER V. ; BERGAMASCHI, VANDERLEI S. ; ANTONIASSI, RODOLFO M. ; TEIXEIRA-NETO, ANGELA A.; LINARDI, MARCELO ; SILVA, JULIO C.M.. Palladium nanoparticles supported on mesoporous biocarbon from coconut shell for ethanol electro‑oxidation in alkaline media. Materials for Renewable and Sustainable Energy, v. 7, n. 4, 2018. DOI: 10.1007/s40243-018-0130-z

    Abstract: Palladium nanoparticles supported on carbon Vulcan XC72 (Pd/C) and biocarbon (Pd/BC) synthesized by sodium borohydride process were used as catalysts for ethanol electro-oxidation in alkaline media. The biocarbon (BC) from coconut shell with mesoporous and high surface area (792 m2 g−1) was obtained by carbonization at 900 °C and the hydrothermal treatment in a microwave oven. The D-band and G-band intensity ratio (ID/IG) from Raman analysis showed high disorder of the biocarbon, while X-ray photoelectron spectroscopy (XPS) suggests higher percentage of oxygen groups on the surface of biocarbon than of Vulcan XC72. From X-ray diffraction (XRD), it was observed peaks in 2θ degree related to the face centered cubic (fcc) structure of palladium and the mean crystallite sizes calculated based on the diffraction peak of Pd (220) were 5.6 nm for Pd/C and 5.3 nm for Pd/BC. Using Transmission Electron Microscope (TEM), it was observed particles well dispersed on both carbons support materials. The electrocatalytic activity of the materials was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) experiments. The peak current density (on CV experiments) from ethanol electro-oxidation on Pd/BC was 50% higher than on Pd/C, while the current density measured at 15 min of CA experiments was 80% higher on Pd/BC than on Pd/C. The higher catalytic activity of Pd/BC might be related to the large surface area of the biocarbon (792 m2 g−1) vs (239 m2 g−1) of Vulcan carbon, the defects of the biocarbon structure and higher amount of oxygen on the surface than Carbon Vulcan XC 72.

    Palavras-Chave: palladium; nanoparticles; carbon; carbon sources; borohydrides; sodium compounds; liquid fuels; fuel cells

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  • IPEN-DOC 25092

    FEITOSA, SABRINA A.; CAMPOS, FERNANDA; YOSHITO, WALTER K. ; LAZAR, DOLORES R.R. ; USSUI, VALTER ; VALANDRO, LUIZ F.; BOTTINO, MARCO A.; BOTTINO, MARCO C.. Effect of the bonding strategy on the tensile retention of full-contour zirconia crowns. International Journal of Adhesion and Adhesives, v. 85, p. 106-112, 2018. DOI: 10.1016/j.ijadhadh.2018.06.006

    Abstract: This study evaluated the effect of distinct bonding strategies on the retention of full-contour zirconia ceramic (YTZP, FCZ) crowns, and it characterized some physicochemical and mechanical properties of FCZ ceramic and its corresponding glazing system. To evaluate retention strength, dies were made with a dentin-analogue material to simulate a prepared tooth. FCZ crowns were manufactured using CAD-CAM technology and allocated into groups according to the bonding strategy: no ceramic treatment (PF – Panavia F cementation), glaze (GL), tribochemical silica coating (CJ), CJ + GL, and piranha solution followed by glaze (PS + GL). The specimens were subjected to thermocycling and storage in distilled water for 100 days before the retention tests. FCZ presented a porosity volume fraction of 0.2%, an apparent density of 6.06 g/cm3, Vickers hardness of 12.4±0.07 GPa, and fracture toughness of 5.54±0.24 MPam1/2. SEM revealed a homogeneous microstructure composed of submicron-sized grains. XRD identified mainly zirconia's tetragonal phase. Glaze powder morphology was observed to be irregular, with a nanometric particle size, and a diffraction pattern characteristic of an amorphous material with several peaks of leucite. The PF and GL groups had higher retention values. The majority of the groups presented pre-test bonding failures, and two catastrophic failures of the FCZ-crown (GL and PF groups) were noted. The use of an MDP-containing resin cement or glaze application might improve retention of the FCZ crowns.

    Palavras-Chave: zirconium; adhesion; surfaces; yttrium oxides; tetragonal lattices; polycrystals; resins; cements; retention; tensile properties

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  • IPEN-DOC 25090

    FALCAO, R.B. ; DAMMANN, EDGAR D.C.C. ; ROCHA, C.J. ; DURAZZO, M. ; ICHIKAWA, R.U. ; MARTINEZ, L.G. ; BOTTA, W.J.; LEAL NETO, R.M. . An alternative route to produce easily activated nanocrystalline TiFe powder. International Journal of Hydrogen Energy, v. 43, n. 33, p. 16107-16116, 2018. DOI: 10.1016/j.ijhydene.2018.07.027

    Abstract: In this paper, an alternative process route to produce active nanocrystalline TiFe compound was investigated. First, TiH2 and Fe powders were dry co-milled in a planetary ball mill for 5e40 h. TiH2 was selected as precursor powder, instead of Ti powder, due its fragility, which has proved to be beneficial to decrease powders adherence on milling tools. In terms of loose powder mass, milling yields ranged from 90 to 95 wt.%. Next, milled powders were post-heated at 873 K under dynamic high-vacuum for TiFe synthesis reaction. First hydrogen absorption was verified in situ during the cooling process of samples (until the room temperature), being the amount of hydrogen absorbed and desorbed by this samples measured by automated Sievert's apparatus, under constant hydrogen flow rate of 9 cm3. min-1 (dynamic measurements). Besides to allowing the first absorption in situ, the investigated process route also allowed the production of the non-stoichiometric TiFe compound (rich in Ti) in samples milled for shorter times (5 and 10 h), both characteristics associated with maintaining the mechanical compound activity. Each sample absorbed hydrogen at 2 MPa during the cooling process, requiring no additional thermal activation cycles, since the samples milled for shorter times (mainly for 10 h) could absorb hydrogen for the first time more easily. However, the samples milled for longer times (25 and 40 h) shown better results in terms of reversible and storage capacities (0.73 and 0.94 wt.%, respectively).

    Palavras-Chave: nanostructures; powders; titanium hydrides; iron compounds; hydrides; milling; hydrogen storage

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  • IPEN-DOC 25089

    ESTEVES-PEDRO, NATALIA M.; SUGIBAYASHI, KENJI; OSTROSKY, ELISSA A.; FERRARI, MARCIO; SUFI, BIANCA da S. ; MATHOR, MONICA B. ; MORENO, PAULO R.H.; LOURENCO, FELIPE R.; CONSIGLIERI, VLADI O.; BABY, ANDRE R.; KANEKO, TELMA M.. Validation cytotoxicity assay for lipophilic substances. Current Topics in Medicinal Chemistry, v. 18, n. 4, p. 275-286, 2018. DOI: 10.2174/1568026618666180410142829

    Abstract: It is challenging to disperse lipophilic substances in a validated cytotoxicity assay, especially for compounds with log K-ow greater than or equal to 5 that may show false negative results. The purpose of this study was to explain the challenges in conducting a cytotoxicity validated test of lipophilic substances: Minthostachys setosa, Pimenta pseudocaryophyllus, and Drimysbrasiliensis essential oils. Additionally, we compared the equivalence of Neutral Red (NR) and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl) -2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) in detecting cell viability. The Hydrophile-Lipophile Balance (HLB) technique was used to evaluate the dispersion of essential oils and cytotoxicity in accordance to the guidelines of the OECD / GD 129 validated cytotoxicity assay. We compared the equivalence of vital dyes by TOST equivalence test. According to the results, we demonstrated the possibility of using other ways to disperse the lipophilic substances. Based on the HLB theory, we selected polysorbate 20 as the best solubilizing agent of the essential oils studied in D10 culture medium

    Palavras-Chave: toxicity; validation; essential oils; cell cultures; pyrazines; tetrazolium; lipids; solubility

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  • IPEN-DOC 25088

    DURAZZO, MICHELANGELO ; FREITAS, ARTUR C. ; SANSONE, ALBERTO E.S. ; FERREIRA, NILDEMAR A.M. ; CARVALHO, ELITA F.U. de ; RIELLA, HUMBERTO G. ; LEAL NETO, RICARDO M. . Sintering behavior of UO2-Er2O3 mixed fuel. Journal of Nuclear Materials, v. 510, p. 603-612, 2018. DOI: 10.1016/j.jnucmat.2018.08.051

    Abstract: The incorporation of burnable neutron absorbers into nuclear fuel pellets is important regarding reactivity compensation, which enables longer fuel cycles. The dry mechanical blending route is the most attractive process to accomplish absorbers incorporation because of its simplicity. By using this route, the present work has investigated the sintering behavior of UO2Er2O3 mixed fuel. A comparison with UO2Gd2O3 sintering behavior was presented. The behavior of UO2Er2O3 fuel sintering was similar to that reported for UO2Gd2O3 fuel, e.g. two-stage sintering with two peaks in the shrinkage rate curves. The effect showed to be less pronounced for Er2O3. This was attributed to the characteristics of the Er2O3 powder particles used as raw-material, whose agglomerates can be more easily broken and thus better homogenized during the blending with UO2 powder. These results confirmed that sinterability depends directly on the quality of the homogenization of the powders, as seen previously. A second phase was experimentally detected in the UO2Er2O3 system, but its impact on the sintering behavior of this mixed fuel has not yet been clarified.

    Palavras-Chave: nuclear fuels; pwr type reactors; diffusion barriers; gadolinium; gadolinium oxides; sintering; solid solutions; uranium dioxide

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  • IPEN-DOC 25087

    DONATUS, UYIME ; VIVEIROS, BARBARA V.G. de ; ALENCAR, MAICON C. de ; FERREIRA, RAPHAEL O.; MILAGRE, MARIANA X. ; COSTA, ISOLDA . Correlation between corrosion resistance, anodic hydrogen evolution and microhardness in friction stir weldment of AA2198 alloy. Materials Characterization, v. 144, p. 99-112, 2018. DOI: 10.1016/j.matchar.2018.07.004

    Abstract: Correlation between corrosion resistance, anodic hydrogen evolution and microhardness in the friction stir weldment of AA2198-T851 alloy has been investigated. Different microscopy techniques, scanning vibrating electrode technique (SVET) and potentiodynamic polarization tests were employed in the investigation. Unlike other 3rd generation Al-Cu-Li alloys where the regions that are most susceptible to corrosion are always within the weld region, the results reveal that the parent material is the most susceptible in this case. There is a direct correlation between corrosion resistance, anodic hydrogen evolution and microhardness in the weldment, and the T1 phase is associated with the direct correlation.

    Palavras-Chave: aluminium alloys; corrosion resistance; friction; microhardness; pitting corrosion; polarization; welded joints

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  • IPEN-DOC 25086

    AGUILA, A. del; SORRIBAS, M.; LYAMANI, H.; TITOS, G.; OLMO, F.J.; ARRUDA-MOREIRA, G. ; YELA, M.; ALADOS-ARBOLEDAS, L.. Sources and physicochemical characteristics of submicron aerosols during three intensive campaigns in Granada (Spain). Atmospheric Research, v. 213, p. 398-410, 2018. DOI: 10.1016/j.atmosres.2018.06.004

    Abstract: Aerosol particles in the submicron range and their physicochemical characteristics were investigated for the first time in Granada, southeastern Iberian Peninsula, during three intensive campaigns. The physical and chemical characteristics were analysed during two spring campaigns and one autumn campaign. New particle formation (NPF) events were found to be more frequent in spring than in autumn. The mean duration, growth rates and maximum diameters had ranges of 5.3–13.2 h, 2.4–4.0 nm h−1 and 35–47 nm, respectively. In addition, one shrinkage event occurred and had a duration of 2.2 h and a shrinkage rate of −2.5 nm h−1. During a period of atmospheric stagnation conditions under the influence of mountain breezes, three consecutive NPF events occurred. The high frequency of the NPF events was attributed to higher temperature and radiation levels and lower relative humidity than during a previous day with similar stagnant conditions but no nucleation occurrence. According to correlation analysis, mineral components correlated with particle number in the Aitken mode, while metals and secondary inorganic aerosols correlated with particle number in the finer and larger fractions, respectively. Pollutants such as CO, NO2, NO and black carbon showed moderate and high correlations with particle number in the submicron fraction. To assess the impact of the particle number contribution according to sources, a new approach was introduced using black carbon concentrations, resulting in four major contributors: urban background, traffic, NPF and biomass burning. The proposed approach was validated by means of different models based on the aerosol spectral dependencies and chemical compositions that classify aerosol populations. Both the models and the proposed approach identified biomass burning and fossil fuel particles during the same periods, and the results showed good agreement. The proposed approach can guide future studies attempting to account for submicron particle contributions in other urban environments.

    Palavras-Chave: chemical composition; biomass; aerosols; scattering; pollutants; gaseous wastes; particles

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  • IPEN-DOC 25084

    DARRIBA, GERMAN N.; MUNOZ, EMILIANO L.; CARBONARI, ARTUR W. ; RENTERIA, MARIO. Experimental TDPAC and theoretical DFT study of structural, electronic, and hyperfine properties in (111In → )111Cd-doped SnO2 semiconductor: Ab initio modeling of the electron-capture-decay after-effects phenomenon. Journal of Physical Chemistry C, v. 122, n. 30, p. 17423-17436, 2018. DOI: 10.1021/acs.jpcc.8b03724

    Abstract: In this paper we investigate the effect of Cd doping at ultralow concentrations in SnO2 both experimentally, by measuring the temperature dependence of the electric quadrupole hyperfine interactions with time-differential γ–γ perturbed angular correlation (TDPAC) spectroscopy using 111Cd as probe nuclei, and theoretically, by performing first-principles calculations based on the density functional theory. TDPAC spectra were successfully analyzed with a time-dependent on–off model for the perturbation factor. These results show combined dynamic plus static interactions whose electric-field-gradients were associated in this model to different stable electronic configurations close to the Cd atoms. The dynamic regime is then originated in fast fluctuations between these different electronic configurations. First-principles calculation results show that the Cd impurity introduces a double acceptor level in the top of the valence band of the doped semiconductor and produces isotropic outward relaxations of the nearest oxygen neighbors. The variation of the calculated electric-field gradient tensor as a function of the charge state of the Cd impurity level shows an interesting behavior that explains the experimental results, giving strong support from first-principles to the electron-capture after-effects proposed scenario. The electron-capture decay of the parent 111In to 111Cd as well as the double acceptor character of the 111Cd impurity and the electric nature of the host are shown to contribute to the existence of these types of time-dependent hyperfine interactions.

    Palavras-Chave: semiconductor materials; spectroscopy; tantalum 181 target; hyperfine structure; doped materials; measuring methods; polycrystals

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  • IPEN-DOC 25083

    COUTO, C.P. ; POLITANO, R. ; GOMES, M.P. ; COLOSIO, M.A.; ROSSI, J.L. . Diffusion analyses using GDOES technique of the 22MnB5 press hardened steel with Al-Si and Zn-Ni coatings. Materials Science Forum, v. 930, p. 472-477, 2018. DOI: 10.4028/www.scientific.net/MSF.930.472

    Abstract: The hot stamping process consists to heat the steel blank, at total austenitization temperatures and to transfer it into the press tooling for forming and fast cooling to fully martensitic transformation. This transference from furnace to press stage promotes some steel oxidation. The application of metallic coatings avoids this phenomenon. The Al-Si coating, a patented process, has been the most applied on steel. Hence, alternative coatings like Zn-Ni are under development. It is known that this furnace heating causes chemical elements diffusion that results in intermetallics formation. This study had the objective of analyze the diffusion profiles of chemical elements present in the substrate, 22MnB5 steel, and coatings of Al-Si and Zn-Ni, using glow-discharge optical emission spectroscopy - GDOES and to correlate the results with those obtained with energy dispersive X-ray spectroscopy - EDS. The results showed that for the Zn-Ni sample, the Zn and Fe profiles at the interfacial zone, are predominant; which justify the high proportion of ZnFe phases as showed using scanning electron microscopy - SEM images. For the Al-Si sample at the interfacial zone, the profile of Al and Fe varies simultaneously; besides that, silicon diffusion in the substrate is more effectively than the nickel diffusion. For this reason, it was possible to identify AlFeSi phase near to the steel substrate.

    Palavras-Chave: steels; aluminium oxides; silicon alloys; coatings; intermetallic compounds; glow discharges; emission spectroscopy; metals; corrosion protection; hardening; presses

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  • IPEN-DOC 25082

    COSTA, ANDREA da; ZORGI, NAHIARA E.; NASCIMENTO, NANCI do ; GALISTEO JUNIOR, ANDRES J.; ANDRADE JUNIOR, HEITOR F. de. Gamma irradiation of Toxoplasma gondii protein extract improve immune response and protection in mice models. Biomedicine & Pharmacotherapy, v. 106, p. 599-604, 2018. DOI: 10.1016/j.biopha.2018.06.155

    Abstract: Gamma radiation induces protein changes that enhance immunogenicity for venoms, used in antivenin production. Coccidian parasites exposed to gamma radiation elicit immune response with protection in mice and man, but without studies on the effect of gamma radiation in soluble acellular extracts or isolated proteins. Toxoplasmosis is a highly prevalent coccidian disease with only one vaccine for veterinary use but with remaining tissue cysts. Total parasite extracts or recombinant proteins used as immunogen induce usually low protection. Here, we study gamma radiation effect on T. gondii extracts proteins (STAG) and its induced immunity in experimental mice models. By SDS-PAGE, protein degradation is seen at high radiation doses, but at ideal dose (1500 Gy), there are preservation of the antigenicity and immunogenicity, detected by specific antibody recognition or production after mice immunization. Immunization with STAG irradiated at 1500 Gy induced significant protection in mice immunized and challenged with distinct T. gondii strains. In their blood, higher levels of specific CD19+, CD3+CD4+ and CD3+CD8+ activated cells were found when compared to mice immunized with STAG. Irradiated T. gondii tachyzoites extracts induce immune response and protection in mice in addition, could be a feasible alternative for Toxoplasma vaccine.

    Palavras-Chave: gamma radiation; parasites; immunity; vaccines; proteins; glycoproteins; immune reactions; mice

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  • IPEN-DOC 25081

    CORDEIRO, GUILHERME L. ; CAMARGO, ELAINE F. de ; SANTOS, MONIQUE C.L. ; PEREIRA, CONRADO V. ; USSUI, VALTER ; LIMA, NELSON B. de ; NETO, ALMIR O. ; LAZAR, DOLORES R.R. . Improved Pt/CeO2 electrocatalysts for ethanol electro-oxidation. International Journal of Electrochemical Science, v. 13, n. 7, p. 6388-6401, 2018. DOI: 10.20964/2018.07.58

    Abstract: A simple and low-cost approach for the preparation of wide-gap (Eg = 3.43 eV), fine cerium dioxide crystals (CeO2, d = 8.1 nm), was developed in order to support Pt nanoparticles as electrocatalysts for ethanol oxidation. Cerium oxide powders were prepared by precipitation from cerium chloride solution in ammonia medium and the influence of calcination temperature was evaluated. Platinum nanoparticles were incorporated by a wet chemical reduction of chloroplatinic acid with sodium borohydrate. Compared to a state-of-the-art Pt/C, the nanocomposite exhibited a much higher mass activity (2.5×) and significant anti-poisoning ability. The promotional effect of the CeO2 nanocrystals was discovered to be affected by heat treatment conditions. Compared to oven-dried samples, calcination allows to (i) an enhanced metal–support interaction between CeO2 and Pt and (ii) an enhancement of electron transportation to catalyst owing to the shrinkage of CeO2 bandgap, thereby promoting the oxidation of the strongly adsorbed CxHy. Therefore, the Pt/CeO2 nanocomposite appears to be a promising electrocatalyst for advanced energy conversion.

    Palavras-Chave: electrocatalysts; platinum; cerium oxides; crystal growth; energy gap; proton exchange membrane fuel cells; electrochemistry; ethanol; oxidation

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  • IPEN-DOC 25080

    CONTURBIA, G.L.C.R. ; DURAZZO, M. ; CARVALHO, E.F.U. de ; RIELLA, H.G. . Phase quantification in UAlx-Al dispersion targets for Mo-99 production. Journal of Nuclear Materials, v. 509, p. 465-477, 2018. DOI: 10.1016/j.jnucmat.2018.07.029

    Abstract: Uranium aluminide (UAlx) is a mixture of three distinct intermetallic compounds comprised of UAl2, UAl3 and UAl4, where the “x” is used to denote a mixture of those phases. Usually UAlx is formed during the target fabrication process by means of a solid state reaction between the uranium aluminide and aluminum. Quantitative techniques such as image analysis and X-ray diffraction using the Rietveld method were compared for their applicability in the determination of the UAl2, UAl3 and UAl4 concentrations, both in the UAl2 primary ingot and in the UAlx-Al dispersion. The UAlx composition was quantified in all stages of the target manufacturing. The image analysis method was shown to be useful for UAlx phase quantification in the primary UAl2 ingot, but was not applicable in the case of UAlx-Al dispersions. The X-ray diffraction method allowed the quantification of the existing UAlx phases in both the primary ingot and UAlx-Al dispersions. Possible sources of error are discussed. The method of quantification based on X-ray diffraction was shown to be appropriate to monitor the evolution of UAlx phases during the manufacturing process.

    Palavras-Chave: diffraction methods; dispersions; image processing; mapping; molybdenum 99; x-ray diffraction

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  • IPEN-DOC 25079

    CHURA-CHAMBI, ROSA M. ; FRAGA, TATIANA R.; SILVA, LUDMILA B. da; YAMAMOTO, BRUNO B.; ISAAC, LOURDES; BARBOSA, ANGELA S.; MORGANTI, LIGIA . Leptospira interrogans thermolysin refolded at high pressure and alkaline pH displays proteolytic activity against complement C3. Biotechnology Reports, v. 19, n. e00266, p. 1-7, 2018. DOI: 10.1016/j.btre.2018.e00266

    Abstract: Enzymes from the thermolysin family are crucial factors in the pathogenesis of several diseases caused by bacteria and are potential targets for therapeutic interventions. Thermolysin encoded by the gene LIC13322 of the causative agent of leptospirosis, Leptospira interrogans, was shown to cleave proteins from the Complement System. However, the production of this recombinant protein using traditional refolding processes with high levels of denaturing reagents for thermolysin inclusion bodies (TL-IBs) solubilization results in poor recovery and low proteolytic activity probably due to improper refolding of the protein. Based on the assumption that leptospiral proteases play a crucial role during infection, the aim of this work was to obtain a functional recombinant thermolysin for future studies on the role of these metalloproteases on leptospiral infection. The association of high hydrostatic pressure (HHP) and alkaline pH was utilized for thermolysin refolding. Incubation of a suspension of TL-IBs at HHP and a pH of 11.0 is non-denaturing but effective for thermolysin solubilization. Soluble protein does not reaggregate by dialysis to pH 8.0. A volumetric yield of 46 mg thermolysin/L of bacterial culture and a yield of near 100% in relation to the total thermolysin present in TL-IBs were obtained. SEC-purified thermolysin suffers fragmentation, likely due to autoproteolysis and presents proteolytic activity against complement C3 α-chain, possibly by a generation of a C3b-like molecule. The proteolytic activity of thermolysin against C3 was time and dose-dependent. The experience gained in this study shall help to establish efficient HHP-based processes for refolding of bioactive proteins from IBs.

    Palavras-Chave: bacteria; enzymes; metalloproteins; fluorescence; lysine; proteins; hydrostatics; pressure dependence

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  • IPEN-DOC 25078

    CASTRO, M.C. ; SILVA, N.F. ; CALDAS, L.V.E. . Testing an extrapolation chamber in computed tomography standard beams. Journal of Physics: Conference Series, v. 975, p. 1-4, 2018. DOI: 10.1088/1742-6596/975/1/012066

    Abstract: The computed tomography (CT) is responsible for the highest dose values to the patients. Therefore, the radiation doses in this procedure must be accurate. However, there is no primary standard system for this kind of radiation beam yet. In order to search for a CT primary standard, an extrapolation ionization chamber built at the Calibration Laboratory (LCI) of the Instituto de Pesquisas Energéticas e Nucleares (IPEN), was tested in this work. The results showed to be within the international recommended limits.

    Palavras-Chave: computerized tomography; depth; dosimetry; extrapolation chambers; leakage current; performance testing; stabilization; standards; x-ray sources; brazilian cnen

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  • IPEN-DOC 25077

    CASTRO, LILIANA ; MOREIRA, EDSON G. ; VASCONCELLOS, MARINA B.A. ; LANGE, CAMILA N. ; PEDRON, TATIANA; BATISTA, BRUNO L.. Stability assessment of a bovine kidney reference-material candidate. Journal of Radioanalytical and Nuclear Chemistry, v. 317, n. 2, p. 1133-1139, 2018. DOI: 10.1007/s10967-018-5928-8

    Abstract: Reference materials are used worldwide and necessary for quality control purposes during analytical determinations. The present study describes the stability evaluation of a bovine kidney reference-material candidate. An isochronous layout was performed, in which the flasks involved are exposed at different temperatures for different time periods and then are analyzed at the same time at the end of the study. The mass fractions of ten inorganic constituents were determined using instrumental neutron activation analysis and inductively coupled plasma mass spectrometry. Statistical analysis, univariate and multivariate, showed no significant differences in composition between units exposed to the different temperatures and times. The reference material may be transported under normal transportation conditions and the certified values and uncertainties will continue to be valid for a period of 2 years.

    Palavras-Chave: calibration standards; icp mass spectroscopy; kidneys; neutron activation analysis; stability

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  • IPEN-DOC 25076

    CASTRO, MARCOS R. de ; MONTEIRO, WALDEMAR A. ; POLITANO, RODOLFO . Enhancements on strength of body structure due to bake hardening effect on hot stamping steel. International Journal of Advanced Manufacturing Technology, p. 1-12, 2018. DOI: 10.1007/s00170-018-2542-4

    Abstract: Body structure projects are designed to develop lightweight structures, which result in low fuel consumption and emissions for internal combustion engines and longer battery life in the case of electric vehicles. The structures need to be lightweight but also strong in order to provide maximum safety to the occupants. These premises have led to the development of special materials such as the hot stamping steels. The most used steel in this process, quenched 22MnB5, also exhibits the bake hardening effect: its yield stress increases after being exposed at temperatures close to 200 °C (typical heat treatment of paint lines in the automotive industry). The aim of this study was to verify the improvement in the mechanical strength of a body structure due to the bake hardening effect to which the hot-stamped steel componentswere submitted. Samples of annealed 22MnB5 steel were submitted to tensile and chemical analysis. A second group of the same steel was subjected to an additional heat treatment in a laboratory furnace simulating the heating that occurs in the body paint line. Subsequently, the same tests were performed with the samples from the first group. Tensile tests evidenced the increase of 6.5% in the yield stress of the samples that suffered the bake hardening effect. The stress-strain diagram curves were used as the input to the side crash simulation program. The simulations demonstrated that the body structure whose hot-stamped parts were subjected the bake hardening effect had a 2% reduction in side crash intrusion compared to body structure where the parts did not suffer this effect. In the case of the lateral protection bar test, the bake hardening effect provided a 5% increase in the maximum bending load.

    Palavras-Chave: hardening; steels; automotive industry; combustion; mechanical properties; internal friction; test facilities

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  • IPEN-DOC 25075

    CASTANHEIRA, BRUNA; TRIBONI, EDUARDO R.; ANDRADE, LUANA dos S.; TRINDADE, FABIANE de J.; OTUBO, LARISSA ; TEIXEIRA, ANTONIO C.S.C.; POLITI, MARIO J.; QUEIROZ, THIAGO B. de; BROCHSZTAIN, SERGIO. Synthesis of novel periodic mesoporous organosilicas containing 1,4,5,8-Naphthalenediimides within the pore walls and their reduction to generate wall-embedded free radicals. Langmuir, v. 34, n. 28, p. 8195-8204, 2018. DOI: 10.1021/acs.langmuir.8b00220

    Abstract: Novel periodic mesoporous organosilicas (PMOs) containing 1,4,5,8-Naphthalenediimide (NDI) chromophores as an integral part of the pore walls were synthesized in acidic conditions, in the presence of inorganic tetraethyl orthosilicate, using triblock copolymer surfactant Pluronic P-123 as a template. The NDI precursor, the bridged silsesquioxane N,N′-bis(3-triethoxysilylpropyl)-1,4,5,8-naphthalenediimide, was synthesized by reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with excess 3-aminopropyltriethoxysilane. A series of samples containing up to 19% (weight %) of NDI were prepared (the materials were labeled PMONDIs). 13C and 29Si solid-state nuclear magnetic resonance revealed that the NDI moiety was intact in the PMONDIs and efficiently grafted to the silica network. Samples with up to 16% NDI load presented an ordered two-dimensional-hexagonal mesoscopic structure, according to small-angle X-ray scattering, transmission electron microscopy, and nitrogen adsorption isotherms. Fluorescence spectra of the PMONDIs showed excimer formation upon excitation, suggesting high flexibility of the organic moieties. Reduction of PMONDIs with aqueous sodium dithionite led to the formation of wall-embedded NDI anion radicals, as observed by the appearance of new visible/near-infrared absorption bands. The PMONDIs were also shown to be efficient photocatalysts in the degradation of sulfadiazine, an antibiotic selected here as a model pollutant, which is usually present in water bodies and wastewater.

    Palavras-Chave: carbon 13; copolymers; fluorescence spectroscopy; naphthalene; nuclear magnetic resonance; photocatalysis; pluronics; porous materials; silica; silicon 29; synthesis; transmission electron microscopy

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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 25073

    CONTATORI, CHESTER ; COUTO, ANTONIO A. ; VATAVUK, JAN; BORGES, ARNALDO A.C. ; LIMA, NELSON B. de ; BALDAN, RENATO. Effect of copper and magnesium on the microstructure of centrifugally cast Al-19%Si alloys. Materials Science Forum, v. 930, p. 484-488, 2018. DOI: 10.4028/www.scientific.net/MSF.930.484

    Abstract: Hypereutectic Al-Si alloys can be used in applications that require high wear resistance. Such wear resistance is achieved by the presence of hard primary silicon particles, allied to the formation of Mg2Si intermetallic phase when magnesium is added in this alloy. Centrifugal casting generates a gradient in the microstructure of hypereutectic Al-Si alloys that can favor such applications. Cylindrical components of Al-19%Si alloy containing added copper and magnesium contents were processed by centrifugal casting. The purpose of this study is to investigate the formation and segregation of particles of primary silicon (β) and Mg2Si in Al-19%Si alloy containing additions of copper and magnesium. Because the density of silicon (2.33 g/cm3) and Mg2Si (1.88 g/cm3) is lower than that of aluminum (2.67 g/cm3), centrifugal casting causes primary silicon (β) and Mg2Si particles to concentrate more at the outer wall of the centrifuged pipe. In this study, primary silicon (β) and Mg2Si particles were found to be retained at the outer wall of the pipe. It is believed that the rapid cooling of the molten metal in the region of contact with the mold, whose temperature is lower than that of the molten metal, allied to the centrifugal force, prevented the particles from migrating to the inner wall of the pipe. The microstructure shows a gradient in the distribution of these phases, enabling the production of a functionally graded material. The addition of copper and magnesium leads to the formation of Mg2Si and Al5Cu2Mg8Si6 phases, reducing the amount of primary β phase (Si) particles. In all the evaluated conditions, a tendency is also observed for a gradual increase in the segregation of silicon towards the inner wall along the entire length of the centrifuged pipe.

    Palavras-Chave: aluminium alloys; silicon alloys; wear resistance; copper; magnesium; casting; microstructure

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  • IPEN-DOC 25072

    CAMPOS, FABIO E. de ; PERINI, EFRAIN A. ; ZAPPAROLI JUNIOR, CARLOS L. ; CALVO, WILSON A.P. ; STAROVOITOVA, VALERIIA N.. Main steps for radiopharmaceuticals hot cells validation in accordance with GMP requirements: methodology and practical guide. Journal of Environmental Science and Engineering A, v. 7, p. 132-139, 2018. DOI: 10.17265/2162-5298/2018.03.004

    Abstract: The worldwide GMP (Good Manufacturing Practices) guidelines issued for injectable pharmaceuticals globally agree that the vials filling operation must be performed under air cleanliness Grade A. The air cleanliness classifications adopted by the WHO (World Health Organization) define the particle diameter size, the sampling occupancy state and the limit concentration of viable particles. To reach conformity regarding the microbial limits foreseen at the GMP guidelines, a microbiological monitoring program must be stablished for selected sampling points such as active air sampling, passive air sampling (settle plate method), surfaces sampling (contact method), personnel sampling (gloves and clothes), compressed gas, materials and equipment that may interfere and compromise the product microbiological quality. The key elements for a GMP certification are directly related to a qualification and validation program for radiopharmaceutical manufacturers that must be clearly defined and documented by a validation master plan, foreseen by the manufactures Quality Assurance office. This study describes each qualification step and test for DQ (Design Qualification), IQ (Installation Qualification), OQ (Operation Qualification) and PQ (Performance Qualification) that must be carried out and carefully planned when it comes to hot cells and isolator systems in accordance with the GMP requirements foreseen by international regulatory and supervisory bodies.

    Palavras-Chave: radiopharmaceuticals; production; quality assurance; regulations; standards; monitoring; quality control; inspection

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  • IPEN-DOC 25071

    BUENO, R.C.; MASOTTI, P.H.F. ; JUSTO, J.F.; ANDRADE, D.A. ; ROCHA, M.S. ; TORRES, W.M. ; MESQUITA, R.N. de . Two-phase flow bubble detection method applied to natural circulation system using fuzzy image processing. Nuclear Engineering and Design, v. 335, p. 255-264, 2018. DOI: 10.1016/j.nucengdes.2018.05.026

    Abstract: Natural circulation cooling systems are currently used in new nuclear reactors. Over the last decades, research in these systems has focused in the study of flow and heat transfer parameters. A particular area of interest is the estimation of two-phase flow parameters by image processing and pattern recognition using intelligent processing. Several methods have been proposed to identify objects of interest in bubbly two-phase images. Edge detection is an important task to estimate flow parameters, in which the bubbles are segmented to obtain several features, such as void fraction, area, and diameter. However, current methods face difficulties in determining those parameters in high bubble-density two-phase flow images. Here, a new edge detection method is proposed to segment bubbles in natural circulation instability images. The new method (Fuzzy Contrast Standard Deviation – FUZCON) uses Fuzzy Logic and image standard deviation estimates of locally measured contrast levels. Images were obtained through an experimental circuit made of glass, which enables imaging flow patterns of natural circulation cycles at ambient pressure. The results indicated important improvements on edge detection efficiency for high void fraction estimation on high-density two-phase flow bubble images, when compared to classical detectors, without the need to use smoothing algorithms or human intervention.

    Palavras-Chave: bubbles; cooling systems; detection; fuzzy logic; image processing; natural convection; pattern recognition; two-phase flow; void fraction

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  • IPEN-DOC 25070

    BARABAS, ROBERTA de C. ; LIMA, ANA C. de S. ; SABUNDJIAN, GAIANE . A neuroscience-based methodology to identify the implicit associations of brazilian science teachers towards nuclear technology. International Journal of Development Research, v. 8, n. 6, p. 20904-20909, 2018.

    Abstract: Science, technology, and innovation play an essential role in helping countries increase the quality of life they offer their citizens. Since the discovery of nuclear fission in the 30s, the peaceful applications of nuclear technology have benefited several fields. Improved crops, preservation of food, health, environment protection and a stable supply of energy can be cited as contributions of nuclear technology for global wellbeing. Despite all benefits that result from the peaceful uses of nuclear technology, it is still addressed with prejudice. Prejudices may be explicit (conscious) or implicit (unconscious). Either explicit or implicit, prejudices interfere with individuals’ attitudes. This paper aims to assess the implicit associations of Brazilian science teachers towards nuclear technology by administering the Implicit Association Test (IAT). Identifying their implicit associations will contribute for the understanding of prejudices that may interfere with their teaching. A pretest with nuclear specialists was administered to check the consistency of the IAT. Subsequently, it was administered to the science teachers. The results of the IAT demonstrated more positive associations towards oil. The next step consists of proposing a methodology to change implicit associations of Brazilian science teachers towards nuclear technology.

    Palavras-Chave: neurology; nuclear energy; technology utilization; education; learning; educational facilities; training

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  • IPEN-DOC 25069

    BORTOLETTO, DAIANA R.; LIMA, CASSIO A. ; ZEZELL, DENISE ; SATO, ERIKA T.; MARTINHO, H.. Vibrational spectra calculation of squamous cell carcinoma in the amide band region. Vibrational Spectroscopy, v. 97, p. 135-139, 2018. DOI: 10.1016/j.vibspec.2018.06.007

    Abstract: Alterations in the amide (1500–1700 cm−1) spectral region probed by Fourier-transform infrared spectroscopy (FTIR) have been reported comparing tumor and normal tissues. Usually, bands in this range are assigned to the so-called Amide I, II, and III vibrations which provide pieces of information concerning peptide bonds and secondary structure (α-helix, β-sheet) of proteins. Proteins folding changes due to tumoral process are usually considered to qualitatively explain the observed differences between tumor and normal tissues. In this paper, the observed changes in the FTIR spectra of squamous cell carcinoma compared to normal tissues were analyzed by First-Principles Density Functional Theory vibrational calculations. Computational models for skin and prototype β-sheet model were employed. Our findings shown that predominates conjugated Amide I + Amide II, Amide V, methylene torsions, and ring side chains torsions and swings vibrations in this region. We also notice the lack of evidence concerning changes in the secondary structure of the β-sheet peptidic model to explain the spectral differences. In fact, we concluded that the proline amino acid has the main rule to explain the data in this region being it responsible for the strong coupling between vibrations instead of water.

    Palavras-Chave: carcinomas; tumor cells; biopsy; fiber optics; spectroscopy; computer codes; simulation; melanomas; vibrational states

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  • IPEN-DOC 25068

    BORRELY, S.I. ; GARCIA, V.S.G. ; BORRELY, T.; FAVARO, D.I.T. . Metals, trace elements and ecotoxicity in sediments of the Cubatão River, Brazil. Ecotoxicology and Environmental Contamination, v. 13, n. 2, p. 49-61, 2018. DOI: 10.5132/eec.2018.02.07

    Abstract: The Cubatão River is one of the most important waterways of the coast of São Paulo. The continuous discharge of domestic and industrial effluents into the river and its tributaries resulted in loss of water quality across the system. Industrial and domestic landfills are also located around the studied area. The purpose of this study was to assess two aspects of sediments from the river and two of its tributaries (Perequê and Pilões Rivers): presence of trace elements and toxic metals, and ecotoxicity. Four sampling surveys were conducted from 2010 to 2011 on six different sites (here named P0, P2, P4, P5, P7 and P8). Ecotoxicity was assessed by exposing Hyalella azteca to the collected sediments. Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometry (GF AAS and CV AAS) techniques were applied for measuring concentration of metals and trace elements. The latter enabled quantification of Cd, Pb and Hg, while the former enabled quantification of a wide range of metals and trace elements. As, Cr and Zn concentrations obtained by INAA as well as AAS results were compared to threshold effect levels (TEL) and probable effect levels (PEL), the sediment quality guidelines proposed by the Canadian Council of Ministers of the Environment (CCME) for evaluating the potential effects on aquatic organisms. Cd and Hg values did not exceed TEL at the most of samples. Pb exceeded TEL at only one site campaign. As, Cr and Zn values exceeded TEL in most of sampling sites, with P2 and P4 showing the highest concentrations. Enrichment Factor (EF) and Geoaccumulation Index (IGeo) were calculated for the elements determined by INAA using North American Shale Composite (NASC) and regional background values. In short, As, Br, Cr, Hf, Pb, Sb and Zn were the elements found in concerning amounts, especially As, Br, Cr and Zn. Toxicity results revealed toxic effects on sediments from P2 and P5 (mortality > 50%). Body size analysis demonstrated negative effects at P4 (length smaller than 2,500.00 μm). Data crossing analyses indicate As and Br as main possible contributors to high toxicity levels.

    Palavras-Chave: trace amounts; elements; sediments; heavy metals; neutron activation analysis; absorption spectroscopy; ecology; toxic materials; water; water quality; water pollution; environmental impacts; biological indicators; aquatic organisms

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  • IPEN-DOC 25067

    BORGES, EDUARDO M. ; SABUNDJIAN, GAIANE ; CONTI, THADEU das N. ; BRAZ FILHO, FRANCISCO A.; GUIMARAES, LAMARTINE N.F.. Simulação de um SBLOCA em Angra 2 com o RELAP5 / RELAP5 simulation of the SBLOCA in Angra 2. Ciência, Tecnologia & Ambiente, v. 7, n. 1, 2018. DOI: 10.4322/2359-6643.07102

    Abstract: O objetivo deste trabalho foi simular e avaliar o acidente básico de projeto de perda de refrigerante por pequena ruptura de 50 cm2 na perna fria do circuito primário da usina nuclear Angra 2. Nesta simulação, verificou-se que as lógicas de atuação do Sistema de Proteção do Reator (SPR) e do Sistema de Resfriamento de Emergência do Núcleo (SREN) de Angra 2 utilizadas nesta simulação funcionaram corretamente, mantendo a integridade do núcleo com temperaturas aceitáveis durante todo o evento. Os resultados obtidos foram satisfatórios quando comparados com os apresentados pelo Relatório Final de Análise de Segurança de Angra 2 (FSAR/A2).

    Palavras-Chave: reactors; loss of coolant; primary coolant circuits; safety analysis; eccs; angra-2 reactor; safety

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  • IPEN-DOC 25066

    BORGES, CARLA R.; SAMAD, RICARDO E. ; GONCALVES, KARINA de O.; VIEIRA, DANIEL P. ; COURROL, LILIA C.. Interaction between protoporphyrin IX and tryptophan silver nanoparticles. Journal of Nanoparticle Research, v. 20, n. 6, 2018. DOI: 10.1007/s11051-018-4269-4

    Abstract: Silver nanoparticles (AgNPs) have been intensively studied for several purposes including therapeutic applications in cancer. When prepared with tryptophan and photoreduction, silver nanoparticles (TrpAgNPs) become an alternative to conventional anticancer drugs. In this study, the anticancer activity of synthesized TrpAgNPs against MCF-7 breast cancer cells was evaluated, and the inhibitory concentration (IC50) was found to be ~3.4 mg/mL. Since the protoporphyrin IX (PPIX) concentrations in tumor cells are elevate compared to normal cells, the PPIX-TrpAgNP interaction was studied to investigate if it could contribute for cell apoptosis. The investigation was performed using PPIX solution (0.9 μg/mL) with different TrpAgNP concentrations (from 0 to 13 mg/mL). PPIX was characterized by UV-Vis spectroscopy, steady-state and time-resolved fluorescence spectroscopy. The results have shown that the presence of spherical TrpAgNps with 16-nm diameter quench the PPIX fluorescence intensity. This quenching is strongly dependent on the concentration of the TrpAgNPs, and it is caused by a combination of a static and a dynamic process. The chemical binding leads to oxidation of tryptophan and formation of kynurenine, observed in the emission spectra around 470 nm. The strong reduction of the PPIX fluorescence decay lifetime with nanoparticle increasing concentration confirms the quenching processes due to charge transfer from the excited PPIX states to the resonant silver states. The present study confirms the anticancer activity of TrpAgNPs on the human breast cancer cell line (MCF-7) in vitro and indicates that PPIX-AgNP interaction could contribute with MCF-7 apoptosis.

    Palavras-Chave: concentration ratio; ecological concentration; emission spectra; fluorescence spectroscopy; interactions; mammary glands; nanoparticles; neoplasms; porphyrins; quenching; silver; time resolution; tryptophan

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  • IPEN-DOC 25047

    VEIGA, MARCELLO M.; PASCHOAL, JOSE O.A. . Panorama do setor de materiais e suas relações com a mineração: uma contribuição para a implementação de linhas de P&D. Rio de Janeiro: CETEM/CNPq, 1991. 126 p. (Estudos e Documentos, 16).

    Palavras-Chave: materials; minerals

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  • IPEN-DOC 25065

    BORGES, ARNALDO A.C. ; ARAUJO, MAYARA C. de ; COUTO, ANTONIO A. ; LIMA, NELSON B. de ; CONTATORI, CHESTER . Evaluation of the residual stress and microstructure of extruded and shot peened aluminum alloy 6082. Materials Science Forum, v. 930, p. 507-512, 2018. DOI: 10.4028/www.scientific.net/MSF.930.507

    Abstract: Aluminum-magnesium-silicon alloys have been widely used as extruded products due to its mechanical strength and high ductility. The effects induced by shot peening has been extensively used in materials that have potential for structural applications. In this context, the purpose of this study was to evaluate the residual stress induced by shot peening of extruded aluminum alloy 6082. Initially, the effect of heat treatments such as solution treatment and ageing of this alloy was studied. The residual stress measurements were carried out using x-ray diffraction. The microstructure of the alloy was studied by optical microscopy. The crystallographic texture was determined using x-ray diffraction and back-scattered electron diffraction. The heat treatment sequence that resulted in the highest hardness of Al alloy 6082 was solution treatment at 560ºC for 30 min, followed by ageing at 185ºC for 5 h. The residual stress in compression of the extruded alloy’s surface increased by 87.38%, from -66.6 to -124.8 MPa, caused by shot peening. The residual stress profile indicated an increase in its value up to a depth of 86 μm, beyond which the values obtained were unreliable. The extruded section revealed accentuated crystallographic texture in the (111) plane parallel to the cross-section and in the (200) and (220) planes oriented preferentially in the longitudinal direction to extrusion and perpendicular to the (111) plane.

    Palavras-Chave: aluminium alloys; magnesium alloys; silicon alloys; shot peening; texture; crystallography; residual stresses; x-ray diffraction; x-ray spectrometers

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  • IPEN-DOC 25064

    BORDON, ISABELLA C.; EMERENCIANO, ANDREWS K.; MELO, JULIA R.C.; SILVA, JOSE R.M.C. da; FAVARO, DEBORAH I.T. ; GUSSO-CHOUERI, PALOMA K.; CAMPOS, BRUNO G. de; ABESSA, DENIS M. de S.. Implications on the Pb bioaccumulation and metallothionein levels due to dietary and waterborne exposures: the Callinectes danae case. Ecotoxicology and Environmental Safety, v. 162, p. 415-422, 2018. DOI: 10.1016/j.ecoenv.2018.07.014

    Observação: Corrigendum anexado. Ecotoxicology and Environmental Safety, v. 165, p. 675–676. DOI: 10.1016/j.ecoenv.2018.08.085

    Abstract: This study aimed to assess the bioaccumulation of Pb and induction of metallothionein-like proteins (MT) in Callinectes danae through single and combined dietary and waterborne exposures. Male C. danae individuals were collected in the south area of the Cananéia-Iguape-Peruíbe Protected Area (APA-CIP), in São Paulo State, Brazil. After an acclimatization period, exposure assays were performed during 7 and 14 days, at two Pb concentrations (0.5 e 2.0 µg/g) in 4 treatments: 1) control; 2) contaminated water only; 3) contaminated food only; 4) contaminated water and food. The results indicate that C. danae is highly tolerant to Pb exposure at the evaluated concentrations. In gills, Pb bioaccumulation is more dependent of water efflux and time of exposure (higher Pb values). However, pathways act simultaneously in the induction of MT expression in this tissue. The decreases in Pb accumulation in the combined treatments and MT increases after 14 days in gills suggests that these proteins play a detoxification function in the presence of Pb. In hepatopancreas, depending on the predominance of a certain pathway or combined pathways, accumulation occured at different times. For muscle tissue, bioaccumulation was observed due to contaminated water exposure, but not dietary exposure, probably because Pb concentrations were low.

    Palavras-Chave: biological accumulation; lead; metals; biological markers; crabs; crustaceans; proteins; metallothionein; ecological concentration; seawater; food

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  • IPEN-DOC 25063

    BORBOREMA, SAMANTA E.T. ; OSSO JUNIOR, JOAO A. ; TEMPONE, ANDRE G.; ANDRADE JUNIOR, HEITOR F. de; NASCIMENTO, NANCI do . Pharmacokinetic of meglumine antimoniate encapsulated in phosphatidylserine-liposomes in mice model: a candidate formulation for visceral leishmaniasis. Biomedicine & Pharmacotherapy, v. 103, p. 1609-1616, 2018. DOI: 10.1016/j.biopha.2018.05.004

    Abstract: Visceral leishmaniasis (VL) is a fatal parasitic disease caused by the protozoan Leishmania spp. Meglumine antimoniate (MA) is the main treatment and has demonstrated a promising efficacy in a VL-model when encapsulated into negatively charged liposomes. Considering the current concept for the evaluation of pharmacokinetic parameters at early phases of drug discovery, we developed a formulation of MA-encapsulated into phosphatidylserine liposomes (MA-LP) and analyzed the in vitro antileishmanial activity, physicochemical properties, and pharmacokinetic profile in a mice model. The liposomal formulation had an internal mean diameter of 114 nm and a high stability in plasma. MA-LP was 23-fold more in vitro effective against Leishmania infantum-infected macrophages than the free drug, with a selectivity index higher than 220. The pharmacokinetic studies demonstrated that the liposomes increased the uptake of the drug by the liver and spleen and promoted sustained levels. MA-LP was first eliminated through renal excretion, followed by biliary excretion. In the blood, MA-LP followed a biexponential open model. This work emphasizes the importance of liposomes as potential drug delivery systems for visceral leishmaniasis.

    Palavras-Chave: pharmacology; radionuclide kinetics; parasitic diseases; liposomes; antimony; antimonates; labelling; toxicity

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  • IPEN-DOC 25062

    BEZERRA, S.J.C.; TREVISAN, L.R.; VIANA, I.E.L.; LOPES, R.M.; PEREIRA, D.L. ; ARANHA, A.C.C.; SCARAMUCCI, TAIS. Er,Cr:YSGG laser associated with acidulated phosphate fluoride gel (1.23% F) for prevention and control of dentin erosion progression. Lasers in Medical Science, v. 34, n. 3, p. 449-455, 2019. DOI: 10.1007/s10103-018-2609-3

    Abstract: To evaluate the effect of Er,Cr:YSGG laser, associated with fluoride application, on the prevention/control of dentin erosion. Dentin slabs were embedded in acrylic resin, flattened, and polished. Half of the specimens were previously eroded (10 min immersion in 1% citric acid solution) and half were kept sound. The specimens (n = 10 each substrate) were randomly allocated into the experimental groups, according to the following treatments: control (no treatment); APF gel (1.23% F, 1 min); Er,Cr:YSGG laser irradiation (P1: 0.25W, 20 Hz, 2.8 J/cm2, tip S75, beam diameter of 750 μm, 1mmaway fromthe surface); Er,Cr:YSGG laser irradiation (P2: 0.50W, 20 Hz, 5.7 J/cm2, tip S75, beam diameter of 750 μm, 1 mm away from the surface); APF gel + Er,Cr:YSGG laser P1 and; APF gel + Er,Cr:YSGG laser P2. Afterwards, the specimens underwent an erosion-remineralization cycling, consisting of a 5-min immersion into 0.3% citric acid, followed by 60-min exposure to artificial saliva. This procedure was repeated 4×/day, for 5 days. Surface loss (SL, in μm) was determined by optical profilometry. Specimens from each group were analyzed by environmental scanning electron microscopy (n = 3). Data were statistically analyzed (α = 0.05). For the eroded specimens, APF gel presented the lowest SL, being different from the control. For the sound specimens, none of the groups differed from the control, except for Er,Cr:YSGG laser P2, which presented the highest SL.When substrates were compared, only the eroded specimens of the control and APF + Er,Cr:YSGG laser P1 Groups showed higher SL. Selective structure removal was observed for the laser-treated groups. None of the Er,Cr:YSGG laser parameters were effective in the prevention/control dentin erosion. The laser was also unable to enhance the protection of fluoride against dentin erosion.

    Palavras-Chave: citric acid; dentin; fluorides; gels; laser radiation; lasers; resins; saliva; scanning electron microscopy; sound waves; teeth

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  • IPEN-DOC 25061

    BETINI, EVANDRO G. ; GOMES, MAURILIO P. ; MUCSI, CRISTIANO S. ; LUZ, TEMISTOCLES de S.; ORLANDO, MARCOS T.D.; ROSSI, JESUALDO L. . Study of the thermal diffusivity variation in thin duplex steel plates welded by GTAW process. Materials Science Forum, v. 930, p. 460-465, 2018. DOI: 10.4028/www.scientific.net/MSF.930.460

    Abstract: This study describes the thermal diffusivity of thin duplex steel plates in the thickness direction measured using the laser-flash method after welding. The work reports the experimental efforts in recording temperature profiles of the grade UNS S32304 duplex steel during autogenous welding. The butt weld autogenous joints were carried out by the GTAW (gas tungsten arc welding) process with either argon or argon - 2% nitrogen atmospheres. The amount of nitrogen in the heat affected regions, after welding, was measured and correlated with the variation of the thermal diffusivity of the studied material. The temperature profiles were obtained using k-type thermocouples connected to a digital data acquisition system. Different thermal cycles and thermal diffusivity values were observed in the heat-affected zone (HAZ) for both samples. In the solidified zone (SZ) was observed similar increase of the thermal diffusivity values for the plates welded with pure argon and argon plus nitrogen atmosphere.

    Palavras-Chave: argon; gas tungsten-arc welding; heat affected zone; microstructure; nitrogen; plates; steels; temperature distribution; thermal diffusivity

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  • IPEN-DOC 25060

    BERTOLETE, M. ; BARBOSA, P.A. ; MACHADO, A.R.; SAMAD, R.E. ; VIEIRA JUNIOR, N.D. ; VILAR, R.; ROSSI, W. de . Effects of texturing the rake surfaces of cemented tungsten carbide tools by ultrashort laser pulses in machining of martensitic stainless steel. International Journal of Advanced Manufacturing Technology, v. 98, n. 9-12, p. 2653-2664, 2018. DOI: 10.1007/s00170-018-2407-x

    Abstract: The present study investigates the effect of texturing the rake face of uncoated cemented tungsten carbide tools by ultrashort laser pulses for tribological improvement. In this sense, four parallel micro-groove texturing patterns were created on the rake face of the cutting tools, beginning at a variable distance from the cutting edge. The pitch between grooves was also varied. Friction force, machining force, chip features, and surface roughness were evaluated from semi-orthogonal dry turning in the reference (nontextured) and textured tools. The results showed friction force reduction by nearly 40%; chip deformation decrease around 21%; machining force reduction by 20%; and surface roughness by 46 and 28% for Ra and Rz, respectively, for the best texturing pattern.

    Palavras-Chave: tungsten carbides; cermets; stainless steels; martensitic steels; lasers; pulses; texture; roughness; surfaces; friction factor; machining

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  • IPEN-DOC 25053

    BELLEZZO, MURILLO ; FONSECA, GABRIEL P.; VERRIJSSEN, AN-SOFIE; VONCKEN, ROBERT; BOSCH, MICHIEL R.V. den; YORIYAZ, HELIO ; RENIERS, BRIGITTE; BERBEE, MAAIKE; LIMBERGEN, EVERT J.V.; VERHAEGEN, FRANK. A novel rectal applicator for contact radiotherapy with HDR 192Ir sources. Brachytherapy, v. 17, n. 6, p. 1037-1044, 2018. DOI: 10.1016/j.brachy.2018.07.012

    Abstract: PURPOSE: Dose escalation to rectal tumors leads to higher complete response rates and may thereby enable omission of surgery. Important advantages of endoluminal boosting techniques include the possibility to apply a more selective/localized boost than using external beam radiotherapy. A novel brachytherapy (BT) rectal applicator with lateral shielding was designed to be used with a rectoscope for eye-guided positioning to deliver a dose distribution similar to the one of contact x-ray radiotherapy devices, using commonly available high-dose-rate 192Ir BT sources. METHODS AND MATERIALS: A cylindrical multichannel BT applicator with lateral shielding was designed by Monte Carlo modeling, validated experimentally with film dosimetry and compared with results found in the literature for the Papillon 50 (P50) contact x-ray radiotherapy device regarding rectoscope dimensions, radiation beam shape, dose fall-off, and treatment time. RESULTS: The multichannel applicator designed is able to deliver 30 Gy under 13 min with a 20350 U (5 Ci) source. The use of multiple channels and lateral shielding provide a uniform circular treatment surface with 22 mm in diameter. The resulting dose fall-off is slightly steeper (maximum difference of 5%) than the one generated by the P50 device with the 22 mm applicator. CONCLUSIONS: A novel multichannel rectal applicator for contact radiotherapy with high-doserate 192Ir sources that can be integrated with commercially available treatment planning systems was designed to produce a dose distribution similar to the one obtained by the P50 device.

    Palavras-Chave: radiotherapy; large intestine; rectum; neoplasms; monte carlo method; brachytherapy; dose rates; iridium 192

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  • IPEN-DOC 25057

    BARDELLA, FERNANDO ; MORAES, RAFAEL C. de ; SARINGELOS, THANOS; KARATZAFERIS, ALEXANDROS; RODRIGUES, ANDRE M. ; SILVA, ANDRE G. da ; LEAL NETO, RICARDO M. . Architecting 3D interactive educational applications for the web: the case study of crystalwalk. Multimodal Technologies and Interaction, v. 2, n. 3, p. 1-12, 2018. DOI: 10.3390/mti2030056

    Abstract: This paper describes the technical development of CrystalWalk, a crystal editor and visualization software designed for teaching materials science and engineering aiming to provide an accessible and interactive platform to students, professors and researchers. Justified by the lack of proper didactic tools, an evaluation of the existing crystallographic software has further shown opportunities for the development of a new software, more focused on the educational approach. CrystalWalk’s was guided by principles of free software, accessibility and democratization of knowledge, which was reflected in the application’s architecture strategy and the adoption of state-of-the-art technologies for the development of interactive web applications, such as HTML5/WebGL, service-oriented architecture (SOA) and responsive, resilient and elastic distributed systems. CrystalWalk’s architecture was successful in supporting the implementation of all specified software requirements proposed by state-of-the-art research and deemed to exert a positive impact in building accessible 3D interactive educational applications for the web.

    Palavras-Chave: crystals; computer graphics; educational tools; websites; interactive display devices; crystallography; computer codes; computer architecture

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  • IPEN-DOC 25059

    AZEVEDO, MARIANGELA de B.M. de ; MELO, VITOR H.S. de ; SOARES, CARLOS R.J. ; MIYAMOTO, DOUGLAS M. ; KATAYAMA, RICARDO A. ; SQUAIR, PETERSON L. ; BARROS, CAIO H.N.; TASIC, LJUBICA. Development and characterization of polymeric microparticle of poly(D,L-lactic acid) loaded with holmium acetylacetonate. Journal of Microencapsulation: micro and nano carriers, v. 35, n. 3, p. 281-291, 2018. DOI: 10.1080/02652048.2018.1477843

    Abstract: Biodegradable polymers containing radioactive isotopes such as Holmium 166 (166Ho) have potential applications as beta particle emitters in tumour tissues. It is also a gamma ray emitter, allowing nuclear imaging of any tissue to be acquired. It is frequently used in the form of complexes such as holmium acetylacetonate (HoAcAc), which may cause damages in tissues next to the targets cancer cells, as it is difficult to control its linkage or healthy tissues radiotherapy effects. Poly(d,l-lactic acid), PDLLA, was used to encapsulate holmium acetylacetonate (HoAcAc) using an emulsion solvent extraction/evaporation technique. Microspheres with sizes between 20-53 µm were extensively characterised. HoAcAc release from the microspheres was assessed through studies using Inductively Coupled Plasma – Optical Emission Spectroscopy, and the microspheres showed no holmium leakage after a period of 10 half-lives and following gamma irradiation. Thus, HoAcAc loaded microspheres are here presented as a potential system for brachytherapy and imaging purposes.

    Palavras-Chave: brachytherapy; holmium 166; acetylacetone; lactic acid; polymers; particles; beta particles; microspheres; emulsions; solvents; tumor cells; toxicity

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  • IPEN-DOC 25058

    ARANHA, L.C. ; MUCSI, C.S. ; CEONI, F.C. ; ALENCAR, M.C. ; ROSSI, J.L. . Development of a microtorquemeter for the evaluation of the implant abutment interface behavior. Materials Science Forum, v. 930, p. 520-525, 2018. DOI: 10.4028/www.scientific.net/MSF.930.520

    Abstract: This paper presents the initial developments of a prototype device intended to perform measurements of the fastening torque in the range bellow 1 N.m – hereby denominated microtorque. The device is intended to yield data for analysis of in vitro torquing and detorquing experiments, for fixation and removing of abutments in dental implants and implants in artificial bones. The analysis of the data acquired allowed the authors to observe characteristic fingerprints or signal signatures associated to the type of abutment or implant under experimentation as well as of the mechanical prototype characteristics. In this paper, two different systems of abutment and implant were analyzed. The correlation between the phenomena associated to the signal fingerprints indicate that the developed measurement protocol may be extended to other implant / abutment systems. The authors suggest that the insertion and removal torque curves evaluated in this study would facilitated the correlation between the abutments stability in actual patients and the dynamical behavior under masticatory function.

    Palavras-Chave: torque; dentistry; implants; interfaces; fastening; signals; data analysis; aluminium alloys

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  • IPEN-DOC 25056

    ANTUNES, RENATO A.; OLIVEIRA, MARA C.L. de; FERRAZ, LUCAS C. de C.; GONCALES, LETICIA dos R.; CORREA, OLANDIR V. . Study of the correlation between microstructure and corrosion resistance of the AZ91D magnesium alloy. Materials Science Forum, v. 930, p. 405-410, 2018. DOI: 10.4028/www.scientific.net/MSF.930.405

    Abstract: The aim of the present work was to study the influence of beta phase precipitates content and distribution on the corrosion behavior of the AZ91D magnesium alloy, using samples subjected to solution annealing and aging. The morphology of the beta phase was observed using optical microscopy and scanning electron microscopy. The volume fraction of each phase was also determined. Potentiodynamic polarization tests and immersion tests were carried out, indicating an increase of the corrosion resistance with the volume fraction of the beta phase and its distribution on the grain boundaries of the alpha-phase. Solution annealed samples were more susceptible to corrosion.

    Palavras-Chave: corrosion resistance; microstructure; magnesium alloys; phase transformations; phase studies; precipitation

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  • IPEN-DOC 25055

    ANGELOCCI, LUCAS V. ; YORIYAZ, HELIO . Mesh-based human eye anatomy for Monte Carlo dose calculation. New Frontiers in Ophthalmology, v. 4, n. 4, p. 1-5, 2018. DOI: 10.15761/NFO.1000209

    Abstract: Purpose: The purpose of this work is to explore the capability of the MCNP6 unstructured mesh geometry resources to create an eye and tumor anatomic model for ophthalmic brachytherapy dosimetry. Methods: Abaqus/CAE software was utilized to construct three anatomic eye models using first order tetrahedral mesh elements: a model with a 2 cm in diameter deep tumor; a model with a 1.2 cm in diameter deep tumor; and a model with a 1.2 cm superficial tumor. 2 cm and 1.2 cm COMS applicators fully loaded with Amersham 6711125I seeds were coupled to the eye models for dose calculation using the MCNP6 code. The dose values in the structures of the eye were compared to those obtained using analytical models. Results: Unstructured mesh model has small differences (maximum of 3.4%) in the mass values of the components of the eye comparing to those obtained in the analytical model. Excluding the optical nerve wall, all dose differences were beneath 4% for all structures. The overall dose in the eye agrees within 2% between different models. Conclusions: The feasibility of using unstructured mesh based geometries to model fine structures of the eye has been verified in this study. It was possible to create adequately the anatomic model of the human eye with reproducible dose values compared to reference values.

    Palavras-Chave: monte carlo method; calculation methods; dosimetry; brachytherapy; eyes; mesh generation; neoplasms

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  • IPEN-DOC 25054

    ALVIM, DEBORA S. ; GATTI, LUCIANA V. ; CORREA, SERGIO M.; CHIQUETTO, JULIO B.; SANTOS, GUACIARA M.; ROSSATTI, CARLOS de S. ; PRETTO, ANGELICA ; ROZANTE, JOSE R.; FIGUEROA, SILVIO N.; PENDHARKAR, JAYANT; NOBRE, PAULO. Determining VOCs reactivity for ozone forming potential in the megacity of São Paulo. Aerosol and Air Quality Research, v. 18, n. 9, p. 2460-2474, 2018. DOI: 10.4209/aaqr.2017.10.0361

    Abstract: High ozone (O-3) concentrations are a major concern about air quality in the Sao Paulo Metropolitan Area (SPMA). During 2016, the 8-hour state standard of 140 mu g m(-3) was exceeded on 32 days, whereas the 1-hour national standard of 160 mu g m(-3) was exceeded on 76 days. Exposure to such unhealthy O-3 levels and other pollutants can lead to respiratory disease. The focus of this study is to determine the main O-3 precursor in terms of the volatile organic compounds (VOCs) in order to provide a scientific basis for controlling this pollutant. In this work, 66 samples of hydrocarbons, 62 of aldehydes and 42 of ethanol were taken during the period from September 2011 to August 2012 from 7:00 to 9:00 a.m. The OZIPR trajectory model and SAPRC atmospheric chemical mechanism were used to determine the major O-3 precursors. During the studied period, aldehydes represented 35.3% of the VOCs, followed by ethanol (22.6%), aromatic compounds (15.7%), alkanes (13.5%), ketones (6.8%), alkenes (6.0%) and alkadienes (less than 0.1%). Considering the concentration of VOCs and their typical reactivity, the simulation results showed that acetaldehyde contributed 61.2% of the O-3 formation. The total aldehydes contributed 74%, followed by aromatics (14.5%), alkenes (10.2%), alkanes (1.3%) and alkadienes (e.g., isoprene; 0.03%). Simulation results for the SPMA showed that the most effective alternative for limiting the O-3 levels was reducing the VOC emissions, mainly the aldehydes.

    Palavras-Chave: ozone; air quality; organic compounds; urban areas; air pollution; troposphere; carbon monoxide

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  • IPEN-DOC 25052

    ALVARENGA, LETICIA H.; RIBEIRO, MARTHA S. ; KATO, ILKA T.; NUNEZ, SILVIA C.; PRATES, RENATO A.. Evaluation of red light scattering in gingival tissue – in vivo study. Photodiagnosis and Photodynamic Therapy, v. 23, p. 32-34, 2018. DOI: 10.1016/j.pdpdt.2018.05.016

    Abstract: Antimicrobial photodynamic therapy (aPDT) has been used to treat periodontal disease, thus the aim of this study was to investigate red light (ʎ = 660 nm) attenuation in gingival tissue. This clinical trial included 30 patients with chronic periodontitis; three incisors from each patient were selected for the experimental procedures. A laser source with a radiant power output of 100 mW was used. Two digital photographs were taken of each selected incisor (in frontal and occlusal position). The images were analyzed in the ImageJ program. The results demonstrated that at a 3 mm distance from the laser probe, there is an attenuation of light intensity of 50%, along frontal and occlusal views. Light attenuation in gingival tissue should be considered when setting optimal parameters for antimicrobial photodynamic therapy or photobiomodulation.

    Palavras-Chave: therapy; dentistry; dosimetry; lasers; light scattering; dentin; bone tissues; antimicrobial agents

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  • IPEN-DOC 25051

    ALVARENGA, NUNO; TAIPINA, MAGDA ; RAPOSO, NELIA; DIAS, JOAO; CARVALHO, MARIA J.; AMARAL, OLGA; SANTOS, MARIA T.; SILVA, MARIA M.; LIDON, FERNANDO C.. Development of biscuits with green banana flour irradiated by Co-60: preservation in modified atmosphere packaging. Emirates Journal of Food and Agriculture, v. 30, n. 6, p. 496-502, 2018. DOI: 10.9755/ejfa.2018.v30.i6.1720

    Abstract: Banana it's one of the most consumed fruits in the world but 20% of the production is wasted, mostly due to post-harvest losses, or because it doesn't fit in consumers standards. Nonetheless, Green Banana Flour (GBF) can be an alternative to minimize these losses, further being a good source of nutrients, fiber, resistant starch and micronutrients. Considering the interesting possibilities of GBF utilization in the agrofood sector, the aims of this study, was the development of GBF cookies and preservation during three months in two different types of modified atmosphere. The experimental design considered GBF radiation with gamma radiation (1 kGy and 3 kGy), with additional packaging in modified atmosphere, using 100% CO2 or a gas mixture containing 2% O-2; 88% N-2 e 10% CO2. As a control, non-radiated GBF was used. In general, it was observed that samples submitted to 3 kGy radiation, had the best results. Besides, packaging with gases mixture showed higher efficiency for GBF cookies preservation, due to CO2.

    Palavras-Chave: food; bananas; banana plants; flour; cobalt 60; irradiation; gamma radiation; controlled atmospheres; packaging

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  • IPEN-DOC 25050

    ALMEIDA, MARIANA C. ; SAMPAIO, GENI R.; BASTOS, DEBORAH H.M.; VILLAVICENCIO, ANNA L.C.H. . Effect of gamma radiation processing on turmeric: antioxidant activity and curcumin content. Radiation Physics and Chemistry, v. 152, p. 12-16, 2018. DOI: 10.1016/j.radphyschem.2018.07.008

    Abstract: The aim of this study was to evaluate the effectiveness of gamma radiation from 60Co at doses 0, 5, 10, 15 and 20 kGy on turmeric (Curcuma longa Linn.). The quantification of phenolic compounds was performed by Folin-Ciocalteu method and assessing the potential of antioxidant activity by the free radical [2,2 difenil-1-pricril-hidrazil (DPPH•)] scavenging and by Rancimat® method. The curcumin quantification was performed by High Performance Liquid Chromatography. Compared to control, there were significant losses (p < 0,05) of total phenolic compounds in the samples irradiated with 15 kGy (p = 0001) and 20 kGy (p = 0001). Regardless the irradiation, there was no decrease in the ability to scavenge free radicals. The Antioxidant Activity Index (Rancimat® method) was significantly lower (p < 0,05) in 5 kGy (p < 0001) and 15 kGy (p = 0003) irradiated extracts and the curcumin quantification was significantly lower (p < 0,05) in 15 kGy irradiated extract (p < 0001). It is concluded that gamma radiation processing technology on turmeric can be viable. To maintain safety of antioxidant activity it should be applied doses up 10 kGy.

    Palavras-Chave: antioxidants; cobalt 60; curcumin; food processing; gamma radiation; high-performance liquid chromatography; irradiation; scavenging

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  • IPEN-DOC 25049

    ALMEIDA, GISELE F.C. ; COUTO, ANTONIO A. ; REIS, DANIELI A.P.; MASSI, MARCOS; SILVA SOBRINHO, ARGEMIRO S. da; LIMA, NELSON B. de . Effect of plasma nitriding on the creep and tensile properties of the Ti-6Al-4V alloy. Metals, v. 8, n. 8, p. 1-15, 2018. DOI: 10.3390/met8080618

    Abstract: This work aimed to enhance the creep resistance of Ti-6Al-4V alloy treated by plasma nitriding. The nitriding was performed on specimens with aWidmanstätten microstructure for four hours at 690 C under a gas atmosphere containing Ar:N2:H2 (0.455:0.455:0.090). X-ray diffraction analysis showed that the "-Ti2N and -TiN formed on the nitrided sample, in addition to the -Ti and -Ti matrix phases. The layer thickness of this sample was about 1 m. Hot tensile tests were performed in the temperature range of 500 to 700 C on nitrided and non-nitrided samples, which indicated an increased strength of the nitrided samples. The same temperature range was used for the creep tests in a stress range of 125 to 319 MPa. The plasma-nitrided samples exhibited better creep resistance when compared to the untreated samples. This result was demonstrated by the decreased secondary creep rate and the increased final creep time. This improvement in the creep resistance appeared to be associated with the formation of the nitrided layer, which worked as a barrier to oxygen diffusion into the material and due to the formation of a surface residual compressive stress.

    Palavras-Chave: titanium alloys; plasma; nitridation; nitrides; creep; tensile properties; hot cells

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  • IPEN-DOC 25048

    ALMEIDA, S.B. ; VILLANI, D. ; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L. . Comparative study of the TL response of LiF:Mg,Ti and CaSO4:Dy in the clinical electron beams dosimetry applied to total skin irradiation (TSEB) treatments. Radiation Physics and Chemistry, v. 155, SI, p. 121-126, 2019. DOI: 10.1016/j.radphyschem.2018.05.025

    Abstract: The commissioning and quality assurance The Total Skin Electron Beam (TSEB) irradiation treatment is based on the AAPM's report 23, which describes the six-dual-field (Standford) technique, and the Hospital Israelita Albert Einstein (HIAE) follows this recommended guidance. The Dosimetric Materials Laboratory of the Instituto de Pesquisas Energéticas e Nucleares (IPEN-LMD) has tradition in research related to thermoluminescent materials and its clinical applications. Thus, aiming to apply the LiF:Mg,Ti, the most common TLD material, and CaSO4:Dy + Teflon produced at IPEN as easy-to-use alternatives to electron beams dosimetry and its parameters applied to TSEB, this paper reports a comparative study of the TL responses of both materials to dose evaluation in TSEB treatments. The TL response of both materials was evaluated in several TSEB parameter tests such as clinical field homogeneity, Monitor Units (MU) calculation, absorbed doses over the reference line and throughout the surface of the skin in a treatment simulation using AldersonRando anthropomorphic phantom. Results show that the field homogeneity measurements remained within ± 8% acceptance limit from AAPM Report 23, little to no energy dependency over the range of 4 o 9 MeV electron beams and, for clinical measurements and MU calculations, both TLDs present compatible results and can be used as alternative tools in TSEB dosimetry.

    Palavras-Chave: lithium fluorides; thermoluminescence; thermoluminescent dosimetry; skin; calcium sulfates; dysprosium; dosimetry

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  • IPEN-DOC 25046

    AFFONSO, REGINA ; SOARES, CARLOS R. ; RIBELA, MARIA T. ; BARTOLINI, PAOLO . High production and optimization of the method for obtaining pure recombinant human prolactin. Protein Expression and Purification, v. 152, p. 131-136, 2018. DOI: 10.1016/j.pep.2018.07.015

    Abstract: Prolactin is a pituitary hormone that is involved diverse physiological functions, such as lactation, reproduction, metabolism, osmoregulation, immunoregulation, and behavior. Its level of glycosylation is low in vivo, which favors its expression in bacterial systems. In the present work recombinant human prolactin (rec-hPRL) was expressed from the p1813-hPRL vector in Escherichia coli strain in inclusion bodies with 530.67 mg of rec-hPRL per liter of induced bacterial culture. The solubilization and renaturation of rec-hPRL followed by two methods described in the literature for this protein: one with detergent and basic pH, and other urea and dialyses was done by studying. The protocol with detergent/basic pH was not successful, whereas protocol with urea/dialyses was obtained pure protein and this was optimized. Rec-hPRL was obtained in a soluble, pure and active form, when the sample was 8-fold concentrated in the solubilization phase, allowing 33% recovery, 3-fold more that the original method. The pure protein was obtained with 38.37 i. u./mg activity, which is three times greater than that of the PRL standard from the WHO. In conclusion, this work obtained the highest production of rechPRL, and concentrating the sample eight times in the solubilization stage was decisive for obtaining a highly concentrated, active protein for future work.

    Palavras-Chave: lth; hormones; biological effects; bacteria; proteins; in vitro; bioassay; statistical data; lactogens; pituitary hormones; biotechnology

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  • IPEN-DOC 24395

    VELO, A.F. ; CARVALHO, D.V.S. ; HAMADA, M.M. . Liquid distribution and holdup in the random packed column. Flow Measurement and Instrumentation, v. 62, p. 176-185, 2018. DOI: 10.1016/j.flowmeasinst.2017.11.002

    Abstract: In the present work, a third-generation gamma transmission tomography system was used to evaluate the liquid distributions of a Raschig rings random packed column, at two different water flows: 2 and 6 l/min. For each water flow, the measurements were carried out at nine column heights. The liquid-gas holdup was determined by the reconstructed images. The distribution of the Raschig rings, as well as the position and the average accumulated amount of the water concentration among the Raschig rings were capable to be determined, even at low temporal resolution of the system of 8.8 h. The regions of accumulated water concentration were similar for the water flow velocities at 2 and 6 l/min. The average accumulated water concentration for 6 l/min was higher compared to 2 l/min. The spatial resolution of the tomography system determined by the modulation transfer function (MTF) analysis was of 1.45 mm.

    Palavras-Chave: column packing; distribution; computerized tomography; multiphase flow

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  • IPEN-DOC 24392

    HARAGUCHI, MARCIO I.; CALVO, WILSON A.P. ; KIM, HAE Y.. Tomographic 2-D gamma scanning for industrial process troubleshooting. Flow Measurement and Instrumentation, v. 62, p. 235-245, 2018. DOI: 10.1016/j.flowmeasinst.2017.09.004

    Abstract: Gamma scanning is a nuclear inspection technique widely used to troubleshoot industrial equipments in refineries and petrochemicals plants such as distillation columns and reactors. In this technique, a sealed radiation source and detector move along the equipment, and the intensity readouts generate the density profile of the equipment. Although many improvements have been introduced in recent years, the result of gamma scan still consists of a simple 1-D density plot. In this work, we present the tomographic gamma scanning that, using image reconstruction techniques, shows the result as a 2-D image of density distribution. Clearly, an image reveals more features of the equipment than a 1-D graph and many problems that could not be troubleshooted using the conventional technique can now be solved with this imaging technique. We use ART (Algebraic Reconstruction Technique) intercalated with total variation minimization filter. The use of total variation minimization leads to compressive sensing tomography, allowing to obtain good quality reconstruction from few irradiation data. We simulated the reconstruction of different density distributions. We applied the new technique to data obtained by irradiating with gamma rays phantoms that emulate industrial equipments. Finally, we present the result obtained by applying the innovative technique to real operating distillation column. It seems that the new technique has identified a problem in this equipment that is very difficult to detect using conventional gamma scan.

    Palavras-Chave: gamma radiation; gasers; gamma sources; electron scanning; tomography; distillation

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  • IPEN-DOC 25045

    RODRIGUES, THENNER S. ; MOURA, ARTHUR B.L. de ; SILVA, FELIPE A. e ; CANDIDO, EDUARDO G. ; SILVA, ANDERSON G.M. da; OLIVEIRA, DANIELA C. de; QUIROZ, JHON; CAMARGO, PEDRO H.C.; BERGAMASCHI, VANDERLEI S. ; FERREIRA, JOAO C. ; LINARDI, MARCELO ; FONSECA, FABIO C. . Ni supported Ce0.9Sm0.1O2-δ nanowires: an efficient catalyst for ethanol steam reforming for hydrogen production. Fuel, v. 237, p. 1244-1253, 2019. DOI: 10.1016/j.fuel.2018.10.053

    Abstract: We reported herein the synthesis in high yields (> 97%) of Ce0.9Sm0.1O2-δ nanowires displaying well-defined shape, size, and composition by a simple, fast, and low-cost two-step hydrothermal method. The Ce0.9Sm0.1O2-δ nanowires synthesis was followed by the wet impregnation of Ni without the utilization of any stabilizing agent. The Ni/Ce0.9Sm0.1O2-δ nanowires showed higher surface area, high concentration of oxygen vacancies at surface, and finely dispersed Ni particles with significantly higher metallic surface area as compared with catalysts prepared from commercial materials with similar compositions. Such unique and improved properties are reflected on the catalytic performance of the Ni/Ce0.9Sm0.1O2-δ nanowires towards ethanol steam reforming. The nanowires exhibited high yields for hydrogen production (∼60% of selectivity) and an exceptional stability with no loss of activity after 192 h of reaction at 550 °C. The reported results provide insights and can inspire highyield production of nanostructured catalysts displaying controlled and superior properties that enable practical applications in heterogeneous catalysis.

    Palavras-Chave: nanowires; nanostructures; catalysts; ethanol; hydrogen production; nickel

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  • IPEN-DOC 25044

    MARTINS-JUNIOR, HELIO A. ; LEBRE, DANIEL T.; WANG, ALEXANDRE Y.; PIRES, MARIA A.F. ; BUSTILLOS, OSCAR V. . Residue analysis of glyphosate and Aminomethylphosphonic Acid (AMPA) in soybean using liquid chromatography coupled with Tandem Mass Spectrometry. In: NG, TZI B. (Ed.). Soybean - biochemistry, chemistry and physiology. Rijeka, Croatia: IntechOpen, 2011. p. 495-506, cap. 27. DOI: 10.5772/15817

    Palavras-Chave: pesticides; herbicides; glycine hispida; soybeans; chromatography; mass spectroscopy

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  • IPEN-DOC 25039

    ALVES, ELIANE G.; TOTA, JULIO; TURNIPSEED, ANDREW; GUENTHER, ALEX B.; VEGA BUSTILLOS, JOSE O.W. ; SANTANA, RAONI A.; CIRINO, GLAUBER G.; TAVARES, JULIA V.; LOPES, ALINE P.; NELSON, BRUCE W.; SOUZA, RODRIGO A. de; GU, DASA; STAVRAKOU, TRISSEVGENI; ADAMS, DAVID K.; WU, JIN; SALESKA, SCOTT; MANZI, ANTONIO O.. Leaf phenology as one important driver of seasonal changes in isoprene emissions in central Amazonia. Biogeosciences, v. 15, n. 13, p. 4019-4032, 2018. DOI: 10.5194/bg-15-4019-2018

    Abstract: Isoprene fluxes vary seasonally with changes in environmental factors (e.g., solar radiation and temperature) and biological factors (e.g., leaf phenology). However, our understanding of the seasonal patterns of isoprene fluxes and the associated mechanistic controls is still limited, especially in Amazonian evergreen forests. In this paper, we aim to connect intensive, field-based measurements of canopy isoprene flux over a central Amazonian evergreen forest site with meteorological observations and with tower-mounted camera leaf phenology to improve our understanding of patterns and causes of isoprene flux seasonality. Our results demonstrate that the highest isoprene emissions are observed during the dry and dry-to-wet transition seasons, whereas the lowest emissions were found during the wet-to-dry transition season. Our results also indicate that light and temperature cannot totally explain isoprene flux seasonality. Instead, the camera-derived leaf area index (LAI) of recently mature leaf age class (e.g., leaf ages of 3-5 months) exhibits the highest correlation with observed isoprene flux seasonality (R-2 = 0.59, p < 0.05). Attempting to better represent leaf phenology in the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1), we improved the leaf age algorithm by utilizing results from the camera-derived leaf phenology that provided LAI categorized into three different leaf ages. The model results show that the observations of age-dependent isoprene emission capacity, in conjunction with camera-derived leaf age demography, significantly improved simulations in terms of seasonal variations in isoprene fluxes (R-2 = 0.52, p < 0.05). This study highlights the importance of accounting for differences in isoprene emission capacity across canopy leaf age classes and identifying forest adaptive mechanisms that underlie seasonal variation in isoprene emissions in Amazonia.

    Palavras-Chave: isoprene; isoprene; forests; phenology; leaves; environment; amazon river

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  • IPEN-DOC 25038

    NATALE, LIVIA C.; RODRIGUES, MARCELA C.; ALANIA, YVETTE; CHIARI, MARINA D.S.; BOARO, LETICIA C.C.; COTRIM, MARYCEL ; VEGA, OSCAR ; BRAGA, ROBERTO R.. Mechanical characterization and ion release of bioactive dental composites containing calcium phosphate particles. Journal of the Mechanical Behavior of Biomedical Materials, v. 84, p. 161-167, 2018. DOI: 10.1016/j.jmbbm.2018.05.022

    Abstract: Objective: to verify the effect of the addition of dicalcium phosphate dihydrate (DCPD) particles functionalized with di- or triethylene glycol dimethacrylate (DEGDMA or TEGDMA) on the degree of conversion (DC), post-gel shrinkage (PS), mechanical properties, and ion release of experimental composites. Methods: Four composites were prepared containing a BisGMA/TEGDMA matrix and 60 vol% of fillers. The positive control contained only barium glass fillers, while in the other composites 15 vol% of the barium was replaced by DCPD. Besides the functionalized particles, non-functionalized DCPD was also tested. DC after 24 h (n=3) was determined by FTIR spectroscopy. The strain gage method was used to obtain PS 5 min after photoactivation (n=5). Flexural strength and modulus (n=10) were calculated based on the biaxial flexural test results, after specimen storage for 24 h or 60 days in water. The same storage times were used for fracture toughness testing (FT, n=10). Calcium and phosphate release up to 60 days was quantified by ICP-OES (n=3). Data were analyzed by ANOVA/Tukey test (alpha: 5%). Results: Composites containing functionalized DCPD presented higher DC than the control (p < 0.001). The material containing DEGDMA-functionalized particles showed higher PS than the other composites (p < 0.001). After 60 days, only the composite with DEGDMA-functionalized DCPD presented fracture strength similar to the control, while for flexural modulus only the composite with TEGDMA-functionalized particles was lower than the control (p < 0.001). FT of all composites containing DCPD was higher than the control after 60 days (p < 0.005). Calcium release was higher for the composite with non-functionalized DCPD at 15 days and no significant reductions were observed for composites with functionalized DCPD during the observation period (p < 0.001). For all the tested composites, phosphate release was higher at 15 days than in the subsequent periods, and no difference among them was recorded at 45 and 60 days (p < 0.001). Conclusions: DCPD functionalization affected all the studied variables. The composite with DEGDMA-functionalized particles was the only material with strength similar to the control after 60 days in water; however, it also presented the highest shrinkage. The presence of DCPD improved FT, regardless of functionalization. DCPD functionalization reduced ion release only during the first 15 days.

    Palavras-Chave: composite materials; calcium phosphates; phosphates; spectroscopy; fourier transformation; infrared spectra; dentistry

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  • IPEN-DOC 25037

    BUSTILLOS, OSCAR V. ; SASSINE, ANDRE. A magia da curva cicloide: braquistocrona e tautocrona. São Paulo: Scortecci, 2011. 256 p.

    Notas de conteúdo: Livro disponível somente na versão impressa. Consulte a biblioteca do IPEN.

    Abstract: O livro explora a curva cicloide, desde o gênesis até suas aplicações e também as consequências que acarretaram o estudo da curva cicloide. A obra apresenta os enredos históricos dos protagonistas que estudaram a curva cicloide, mostrando por qual motivo ela é chamada de Helena dos geômetras. Entre os protagonistas estão os irmãos Bernoulli, Newton, Leibniz, Pascal, Roberval, Galileu e outros.

    Palavras-Chave: control theory; functions; differential equations; control; feedback; geometry; mathematics; optimization

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  • IPEN-DOC 25043

    BITELLI, ULYSSES D. . Comissionamento : calibração da potência do reator IPEN/MB-01 pela Técnica de Análise por Ativação Neutrônica. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-RMB-005-00-RELT-084-00). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro (RMB)

    Abstract: Este relatório apresenta o procedimento de comissionamento para a calibração da potência do reator IPEN/MB-01, utilizando a técnica de análise por ativação neutrônica, através da irradiação de folhas de ouro com e sem cobertura (nuas) de cádmio. [1,2,3], posicionadas no interior do núcleo do reator IPEN/MB-01. O valor médio do fluxo de nêutrons e por conseqüência de potência obtido é correlacionado com o valor médio de corrente dos canais nucleares 5 e 6, bem como o valor médio da taxa de contagem do canal 10, respectivamente câmaras de ionização compensada e detector de B-10. Tais medidas são obtidas a partir da irradiação das folhas de ouro a 100 watts de potência, valor este estimado pela técnica de análise por ruído neutrônico em relatório anterior de comissionamento

    Palavras-Chave: commissioning; calibration; reactors; potentials; gold; ipen-mb-1 reactor; neutron activation analysis; cadmium

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  • IPEN-DOC 25042

    DINIZ, RICARDO . Comissionamento : previsão de massa crítica do núcleo do reator IPEN/MB-01 tipo placa. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-RMB-005-00-RELT-080-01). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro (RMB)

    Abstract: Este relatório de comissionamento apresenta um procedimento experimental para a previsão de massa crítica do núcleo do reator IPEN/MB-01 com elementos combustíveis tipo placa, utilizandoa técnica do inverso da multiplicação subcrítica (1/M).

    Palavras-Chave: criticality; critical mass; ipen-mb-1 reactor; fuel elements; fuel plates; loading; uranium; mass

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  • IPEN-DOC 25041

    MURA, LUIZ E.C. . Comissionamento : procedimento de teste de queda das barras de controle no reator IPEN/MB-01 (teste integrado do MAB com as barras de controle). São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-RMB-005-00-RELT-077-00). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro (RMB)

    Palavras-Chave: control elements; commissioning; control rod drives; ipen-mb-1 reactor; reactor control systems; inspection

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  • IPEN-DOC 25040

    MURA, LUIZ E.C. ; BITELLI, ULYSSES D. . Comissionamento : procedimento para o carregamento e descarregamento dos elementos combustíveis do núcleo do reator IPEN/MB-01. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-RMB-005-00-RELT-075-00). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro (RMB)

    Abstract: Este relatório descreve o procedimento para o comissionamento das operações de carregamento e descarregamento dos elementos combustíveis do núcleo do Reator IPEN/MB-01

    Palavras-Chave: fuel elements; commissioning; storage; materials handling; loading; unloading; ipen-mb-1 reactor; fuel plates; specifications; reactor operation; reactors; recommendations

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  • IPEN-DOC 25036

    MURA, LUIZ E.C. . Comissionamento : procedimento para o recebimento, manuseio e estocagem de elemento combustível tipo placa novo no reator IPEN/MB-01. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-RMB-005-00-RELT-069-00). Restrito.

    Título do projeto: Reator Multipropósito Brasileiro (RMB)

    Abstract: Este procedimento de comissionamento trata do processo de recebimento e dos testes das operações de manuseio e armazenamento dos elementos combustíveis tipo placa novos no reator IPEN/MB-01. Também faz parte dos objetivos deste procedimento, testar a inserção ou retirada das Placas Combustíveis avulsas dos Elementos Combustíveis Desmontáveis e a inserção ou retirada das Placas nas Caixas de Estocagem de Placas.

    Palavras-Chave: administrative procedures; storage facilities; fuel plates; specifications; control systems

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  • IPEN-DOC 25035

    MOLNARY, LESLIE de . Arquivo meteorológico da torre A e torre D da CNAAA – período 2000-2017. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Julho, 2018. (IPEN-CEN-PSE-IPPG-006-00-RELT-001-00). Restrito.

    Título do projeto: Prestação de Serviços Tecnológicos

    Abstract: Esse documento apresenta uma análise do arquivo de dados meteorológicos da Central Nuclear Almirante Álvaro Alberto (CNAAA), localizada em Angra dos Reis (RJ), para o período de 2000 a 2017 e que será utilizado pela empresa Tetra Tech Brasil para avalizar o estudo de condições meteorológicas extremas (velocidade do vento, temperatura e precipitação) na área do Complexo de Manutenção Especializada (CME) do Estaleiro e Base Naval (EBN) que a Marinha do Brasil (MB) está construindo no município de Itaguaí (RJ). Devido à ausência de dados meteorológicos no local do empreendimento do EBN, foi informado à Tetra Tech que os dados meteorológicos a CNAAA podem, em primeira análise, ajudar a complementar as informações meteorológicas do estudo de condições meteorológicas extremas, uma vez que, os dados da CNAAA já são coletados a muitos anos pelo sistema de meteorologia, assim como, a distância entre a CNAAA e o EBN de cerca de 63 km e a localização de ambos os empreendimentos na faixa litorânea do Estado do Rio de Janeiro, assegura que os principais fenômenos de mesoescala e de grande escala sinótica podem ser assumidos atuando quase que ao mesmo tempo. As condições meteorológicas locais no EBN, que eventualmente possam apresentar algum mecanismo de circulação diferenciado gerado pela configuração topográfica e/ou disposição do empreendimento em relação à proximidade do oceano, que não apenas as características gerais das circulações de mesoescala e de escala sinótica na região, poderão ser melhor estudadas e caracterizadas quando da implementação e operação continuada do sistema de meteorologia da EBN. Eventualmente, esses mecanismos locais poderão potencializar algum dos parâmetros meteorológicos avaliados (velocidade do vento, temperatura e precipitação pluviométrica).

    Palavras-Chave: meteorology; atmospheric circulation; ships; military facilities; wind loads; climates; rain; data compilation; evaluated data; brazilian cnen; ambient temperature

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  • IPEN-DOC 25034

    YAMAGUCHI, MITSUO . Análise de criticalidade do transporte de elementos combustíveis do núcleo do reator IPEN/MB-01 tipo placa. São Paulo: Instituto de Pesquisas Energéticas e Nucleares - CEN, Setembro, 2018. (IPEN-CEN-PSE-CCN-008-00-RELT-001-00). Restrito.

    Título do projeto: Prestação de Serviços Tecnológicos

    Abstract: Este relatório apresenta a análise de criticalidade dos elementos combustíveis que serão transportados do Centro de Combustível Nuclear (CCN) para o prédio do Reator IPEN/MB-01. A análise foi feita com o sistema SCALE4.4a.

    Palavras-Chave: criticality; transport; fuel elements; ipen-mb-1 reactor; computer calculations; fuel plates; fabrication; multiplication factors

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  • IPEN-DOC 25033

    CABRAL, F.V. ; PELEGRINO, M.T.; SEABRA, A.B.; RIBEIRO, M.S. . Effects of methylene blue-mediated photodynamic inactivation associated to NO-releasing chitosan nanoparticles on cutaneous leishmaniasis in mice. In: INTERNATIONAL PHOTODYNAMIC ASSOCIATION WORLD CONGRESS, 16th, June 08-13, 2017, Coimbra, Portugal. Abstract... 2017. p. 272-272.

    Abstract: Cutaneous leishmaniasis (C L) is a ehronie disease developed by parasites of the genus Leishmania that promotes destruetive.and ulcerated lesions. The available treatments are limited beeause of side effeets, resistanee and toxieity. Reaetive oxygen speeies and nitrie oxide (NO) are potentially toxic to these parasites; Photodynamie inaetivation (PDI) involves the generation af oxidative stress and has been explored as an altemative treatment once it is less expensive and no reports about resistanee have been describedY Additionally, several studies indicate that the administration of exogenous NO donors represents an interesting strategy against CL.3 The aim of this work was to explore the effects Df methylene blue (MB)-mediated PDI in assoeiation with encapsulated NO donors (S-nitroso-MSA) in chitosan nanoparticles (CSNPs) on CL in BALB/e mice using real time bioluminescence. Promastigotes of L. (L) amazonensis transgenie line expressing luciferase were used. Sixteen BALB/e miee were infected in the left footpad with 1.106 promastigotes. After 4 weeks, mice were randomly assigned to experimental groups (n=4): Control (non-treated), PDI (treated only with PDI), PDI+CSNP (submitted to PDI and S-nitroso-MSA-CSNPs) and CSNP (treated only with S-nitroso-MSA-CSNPs). PDI was administered in two sessions separated by 24 h and CSNPs (80 eM) were applied immediately after the second PDI session. PDI was performed using a red LED (0= 660 ± 22 nm), MB (100 IlM), irradiance of 100 mW/cm2 and radiant exposure of 150 J/cm2 • parasite burden was analyzed through luciferase deteetion by bioimaging in the first 96 h following treatment and every week during 4 weeks. Statistically significant differences were considered when p < 0.05. Test groups presented significant reduction in parasite load compared to control during all experimental period. Twenty-four-h after treatments, parasite burden was lower for PDI+CSNP group but no statistically signifieant difference was observed when compared to other test groups. After 48 h, all test groups were similar. Besides, parasite load in test groups remained lower than control following 1, 2,3 and 4 weeks post-treatment. Under conditions used in this study, we conclude that CSNPs were not able to enhance MBmediated PDI efficiency in L. (L) amazonensis-induced CL in mice.

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  • IPEN-DOC 25032

    NUNEZ, SILVIA C.; BAPTISTA, ALESSANDRA; GARCEZ, AGUINALDO S.; MARTINS, RODRIGO A.L.; RIBEIRO, MARTHA S. . The role of light irradiance on methylene blue photodegradation dynamics: is all light equal?. In: INTERNATIONAL PHOTODYNAMIC ASSOCIATION WORLD CONGRESS, 16th, June 08-13, 2017, Coimbra, Portugal. Abstract... 2017. p. 252-252.

    Abstract: Methylene blue (MB) is a well-known photosensitizer (Ps) commonly used for antimicrobial photodynamic therapy (aPDT). Usually aPDT paramenters evaluation involves Ps concentration, its quantum yield for singlet oxygen production (Type II reaction) and the Ps photobleaching rate as a function of the deliveried fluence plus oxygen concentration and consumption on the medium. The role of power density is not often consider.The aim of this study is to evaluate the role of power density over MB photobleaching dynamcs evaluating the dimer/monomer ratio as well as the leuco MB formation under discrete changes in power density keeping the same light fluence. The MB was irradiated using a À = 660nm diode laser (TwinLaser, MMOptics, São Carlos, Brazil), 40mW adjustable from 10 to 10mW, 0.04cm2 • The powers of 10mW, 20mW, 30mW and 40mW were used for 300s, 150s, 100s and 75s respectively. The irradiations were carried out directly in a cover quartz cuvette with an optical path of 1 em. An acrylic mask was made to ensure the coincidence between the irradiation and the reading points. The readings were made from À = 200nm to À = 700nm and analyzed in appropriate software. The DA (dimer absorption) /MA (monomer absarption) was calculated and the ratio between visible and ultraviolet absorption was aIs o calculated. Figure 1 show the result afDA/MA for the different irradiances. Our results demonstrated that discrete changes in light irradiance leads to different dinamiccs . terms ofphotobleaching and DAIMA ratio.

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  • IPEN-DOC 25031

    DIMMER, JESICA; CABRAL, FERNANDA V. ; SABINO, CAETANO P. ; NUNEZ MONTOYA, SUSANA C.; CABRERA, JOSE L.; RIBEIRO, MARTHA S. . Photoinactivation of Leishmania amazonesis by natural anthraquinones. In: INTERNATIONAL PHOTODYNAMIC ASSOCIATION WORLD CONGRESS, 16th, June 08-13, 2017, Coimbra, Portugal. Abstract... 2017. p. 195-195.

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  • IPEN-DOC 25030

    BAPTISTA, A.; NUNEZ, S.C.; MARTIN, A.A.; RIBEIRO, M.S. . Identification of important cellular targets for antimicrobial photodynamic therapy in yeast cell through FT-IR spectroscopy. In: INTERNATIONAL PHOTODYNAMIC ASSOCIATION WORLD CONGRESS, 16th, June 08-13, 2017, Coimbra, Portugal. Abstract... 2017. p. 175-175.

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  • IPEN-DOC 25029

    SABINO, CAETANO P. ; BAPTISTA, MAURICIO da S.; RIBEIRO, MARTHA S. ; LINCOPAN, NILTON. Methylene blue uptake and intermolecular interactions in microbial cells through Fluorescence Lifetime Imaging Microscopy (FLIM). In: INTERNATIONAL PHOTODYNAMIC ASSOCIATION WORLD CONGRESS, 16th, June 08-13, 2017, Coimbra, Portugal. Abstract... 2017. p. 82-82.

    Abstract: Antimicrobial photodynamic therapy (APDT) is a promising tool to counterattack the emerging treat of drug-resistant pathogens. The technique combines low-intensity monochromatic light with a photosensitizer compound to produce reactive oxygen species (ROS) that can damage virtually any type of biomolecules and lead to rapid ce\l death. Since some ROS present diffusion-limited reactivity, most cell damage is co-localized with photosensitizer accumulation site. Hence, imaging photosensitizer accumulation and fluorescence lifetime in the nanoscale can bring a great levei of information to further understand the ultrastructural cellular damage caused by APDT. In this study, we used a FLIM system capable of single-molecule detection to observe the accumulation and interaction sites of methylene blue (MB), a very broadly-used photosensitizer, in yeast, and Gram-positive and Gram-negative bacterial cells, Our data shows fluorescence lifetime contrast, with nanometric resolution, among different cellular structures such as cell wall, membrane and DNA. The images evidentiate differential MB accumulation in microbial cells and the existence of two different populations of MB molecular species: those interacting mostly with the solvent (short-lived, - 0.8 ns) and those interacting with biomolecules (Iong-lived, -2 ns), The short-lived fluorescence predominates in the mucoid capsule of Gram-negative bacteria and cell-wall ofyeast and Gram-positive bacteria while longlived MB fluorescence shows preferential accumulation in DNA-rich sites 1 • It is marked in yeast nucleus and exclusively inside bacterial cells. In fact, literature supports that MB intercalation in nucleic acids stabilizes its excited-states leading to increased "fluorescence "lifetime and efficiency of singlet-oxygen production2 . Our data brings evidence that this sOli of phenomena can be observed by FLIM in the nanoscale and this should bring new insights to the photophysical, photochemical and biological mechanisms of photodynamic therapy.

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  • IPEN-DOC 25028

    FUKUMORI, N. . Quality control in the production of radiopharmaceuticals. Vienna: International Atomic Energy Agency, 2018. 150 p. (IAEA TECDOC series, 1856).

    Abstract: Radiopharmaceuticals are central to nuclear medicine applications for the diagnosis and therapy of human diseases, especially cancers and cardiovascular diseases. In the past few decades, advances in the production and quality control of emerging radiopharmaceuticals have led to the production of new radiopharmaceuticals and the availability of new production routes and methods for existing agents. Various new diagnostic agents in the field (such as 68Ga radiopharmaceuticals and generators) as well as therapeutic agents (such as alpha emitters) have already been added to the clinician toolkit. However, the lack of generic and peer-reviewed quality control guidelines and recommendations for their application in human patients is a major concern. To address this need, and in response to requests from Member States and professional societies, the IAEA developed this publication on quality control in the production of radiopharmaceuticals. It is expected to be of use for all professionals involved in the production and quality control of radiopharmaceuticals worldwide. This publication is an outcome of the work of an international team of experts in the field between 2016 and 2018. The IAEA wishes to thank the experts for their contributions. Special thanks are due to J. Ballinger (United Kingdom) for compiling the material, and J.S. Vera Araujo (Bolivarian Republic of Venezuela) for her editorial support. The IAEA officer responsible for this publication was A.R. Jalilian of the Division of Physical and Chemical Sciences.

    Palavras-Chave: radiopharmaceuticals; quality control; radioisotopes; pharmacology; drugs; production; radioactive materials

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  • IPEN-DOC 25027

    BUSTILLOS, OSCAR V. . A espectrometria de massas e a química analítica. Revista Analytica, v. 16, n. 96, p. 36-37, 2018.

    Palavras-Chave: mass spectroscopy; chemical analysis; ions; cathodic protection; hydrogen

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  • IPEN-DOC 25024

    VIEIRA, A.; SAMAD, R.E. ; VIEIRA JUNIOR, NILSON D. ; ROSSI, WAGNER de . Ablação a laser com pulsos ultracurtos do aço DIN 16MnCr5: um estudo do processo de furação / Laser ablation with ultrashort laser pulses in steel DIN 16 MnCr5: a study of drill process. In: CONGRESSO BRASILEIRO DE ENGENHARIA DE FABRICACAO, 9., 26-29 de junho, 2017, Joinville, SC. Anais... Rio de Janeiro, RJ: Associação Brasileira de Engenharia e Ciências Mecânicas, 2017.

    Abstract: A indústria automobilística tem como um de seus principais desafios, e consequentemente, foco de pesquisa, a redução do coeficiente de atrito entre alguns componentes e sistemas presentes nos automóveis. Um dos grandes benefícios dos avanços nesta área é o aumento da vida útil dos componentes e a melhor eficiência do motor. Desta maneira, uma das formas propostas pela tribologia para a redução de atrito é a texturização de superfícies por laser. Neste trabalho, foi abordada a interação de pulsos laser de femtossegundos com o aço DIN 16MnCr5, utilizado na indústria automotiva. Objetivou-se buscar os melhores parâmetros de processo para obter micro cavidades com pouca ou nenhuma zona afetada pelo calor e sem a presença de rebarbas e material ressolidificado, presentes na texturização com laser de pulsos longos (nanossegundos). Para a realização do estudo foi utilizada a técnica de escaneamento diagonal, D-Scan, para determinação dos limiares de ablação em função da sobreposição de pulsos. Também foram realizados estudos de formação das cavidades com a variação da posição do ponto focal e do perfil espacial do feixe laser. São apresentados resultados de análises obtidas por microscopia óptica e de varredura e interferometria de luz branca.

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  • IPEN-DOC 25025

    HERRERA, CRISTHIANO C. ; SAMAD, RICARDO E. ; VIEIRA JUNIOR, NILSON D. ; ROSSI, WAGNER de . Development and control of microfluidic systems. In: WORKSHOP INFO, 1., 01 de julho, 2017, Recife, PE. Resumo expandido... 2017.

    Abstract: The first stage of the project was to perform tests for controlled and optimized machining of BK7 optical glass by femtosecond laser. Parameters such as energy, overlapping pulses, and the focal position variation were investigated for a better extraction of the material. Microchannels, microvalves, micropumps, mixers, reactors, heaters and other components were developed to compose applied microfluidic systems. Microchannels built in BK7 glass separated by a PDMS film form the basis of the microfluidic circuits. The reagent flow control is done by pneumatic mini-valves controlled by an Arduino microcontroller through a Labview platform. This work shows the components developed and two microfluidic systems created. The first contains a microfluidic circuit capable of replicating enzyme-linked immunosorbent assays (ELISA) with a much lower cost of materials. The second has a microfluidic circuit for the production of NaYF4 fluorescent nanocrystals specially used as markers in images of biological systems.

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  • IPEN-DOC 25026

    GOMES, MAURILIO P. ; SANTOS, IGOR P. dos ; COUTO, CAMILA P. ; MUCSI, CRISTIANO S. ; COLOSIO, MARCO A.; ROSSI, JESUALDO L. . Têmpera ao ar de insertos de assentos de válvulas obtidos com aço ferramenta AISI D2. In: CONFERENCIA BRASILEIRA SOBRE TEMAS DE TRATAMENTO TERMICO, 8., 21-24 de maio, 2017, Indaiatuba, SP. Anais... 2017.

    Abstract: A obtenção de insertos de assentos de válvulas por metalurgia de pó usando uma mistura de pó de ferro e aços rápidos ou aços ferramenta está atendendo os requisitos para a substituição do cobalto e chumbo em peças comerciais, visando a redução de custo e evitando a toxicidade do chumbo. O objetivo do presente trabalho foi o de tratar termicamente e caracterizar os insertos de assentos de válvulas sinterizados obtidos utilizando-se uma mistura de pós. Essa mistura de pós foi constituída pelo aço ferramenta AISI D2, ferro, sulfato de manganês, carboneto de nióbio, grafite, estearato de zinco e cobre. O ciclo de temperatura da têmpera ao ar foi determinado por meio do termopar tipo k acoplado a um sistema de aquisição de dados. As propriedades físicas e mecânicas foram medidas em relação à dureza aparente dos insertos, densidade aparente e a sua resistência à ruptura radial. A caracterização microestrutural foi realizada utilizando-se a microscopia óptica, microscopia eletrônica de varredura e espectroscopia por dispersão de energia. Os insertos temperados ao ar e duplamente revenido a 500 °C mostraram os melhores resultados no que tange a dureza e resistência à ruptura radial.

    Palavras-Chave: sintered materials; valves; machining; powder metallurgy; heat treatments

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  • IPEN-DOC 25022

    PERES, JOSE C.G.; HERRERA, CRISTHIANO da C. ; ROSSI, WAGNER de ; VIANNA JUNIOR, ARDSON dos S.. Analysis of a microreactor for synthesizing nanocrystals by computational fluid dynamics. In: WORLD CONGRESS OF CHEMICAL ENGINEERING, 10th, October 01-05, 2017, Barcelona, Spain. Proceedings... 2017.

    Abstract: A microreactor designed to synthesize nanocrystals was built applying laser pulses with duration of femtoseconds in a quartz board. This precise machining technology allowed dimensioning the microchip cross section as a trapezoidal shape with base lengths of 120 μm and 200 μm and depth of 150 μm. The microchip is comprised of four inlets for reactants, a mixing section with 40 curves after the inlet section to ensure proper mixing of the species and 22 serpentine channels, with 22,000 μm length each, to allow crystal growth. Flow field throughout the microchip was investigated by computational fluid dynamics considering inlet flow rates between 12.5 and 2000 μL min-1. Hexahedral meshes were used to discretize the geometry as its cross section is uniform and to reduce the total number of elements. Advection terms were solved by the high resolution scheme. Numerical solutions were converged when the maximum residual value was less than 10-4 and the domain imbalance was less than 1%. Flow throughout the channels is laminar as the maximum Reynolds number observed is 850. The tridimensional velocity profile is a paraboloid whose vertex is influence by the centrifugal force: at the curved sections, such force accelerates flow towards the outer part of the channels, moving the maximum velocity point to this zone. The centrifugal force also creates secondary flows. These structures enhance mixing in the direction perpendicular to the main flow and behave like turbulent flows in macroscopic systems, allowing proper mixing without additional power consumption. Proper coupling between microchip geometry and its operating conditions was verified by simulating the dispersion of a non-reactive tracer injected in one of the inlet ports while feeding the others with water. For low flow rates, the tracer flows parallel to the water stream up to half of the mixing section and full mixing occurs after the second serpentine channel. For flow rates higher than 250 μL min-1, it shows secondary fluxes are intensified and promote mixing after both the third curve at the mixing section and at the beginning of the serpentine channels after the fourth reactant inlet, ensuring better conditions if the desired reaction is limited by contact between the reactants.

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  • IPEN-DOC 25016

    BRASCHI, GIOVANI F.; EIRAS, JOSE A.; BARBOSA, PATRICIA A. ; ROSSI, WAGNER de ; CARNEIRO, MARCELO B. . Desenvolvimento de material em gradação funcional de metal duro e aço rápido para ferramenta de corte / Development of functionally graded material of cemented carbide and high speed steel for cutting tool. In: CONGRESSO BRASILEIRO DE ENGENHARIA DE FABRICACAO, 9., 26-29 de junho, 2017, Joinville, SC. Anais... Rio de Janeiro, RJ: Associação Brasileira de Engenharia e Ciências Mecânicas, 2017.

    Abstract: Material em gradação funcional (Functionally Graded Material – FGM) tem sido considerado como uma nova classe de material, na qual materiais com propriedades distintas são unidos na forma de um gradiente, formando uma unidade estrutural com propriedades não uniformes. O objetivo deste trabalho é apresentar a caracterização de amostras em gradação funcional de metal duro e aço rápido. Para tanto, foram utilizados pós de metal duro (K20) e aço rápido (T6), que foram sinterizados por uma técnica comumente conhecida como SPS (Spark Plasma Sintering). A caracterização foi feita a partir da avaliação da microestrutura em microscópio laser confocal e eletrônico de varredura, determinação da densidade relativa pelo princípio de Arquimedes e avaliação do perfil de dureza Vickers ao longo seção transversal das amostras. Os resultados mostraram uma microestrutura com ausência de trincas de origem térmica, com maior valor de densidade relativa de 98,70% e com variação no perfil de dureza ao longo da espessura da amostra, o que evidencia propriedades não uniformes.

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  • IPEN-DOC 25023

    LARA, J.A.C. ; COUTO, C.P. ; COLOSIO, M.A.; ROSSI, J.L. ; ABBADE, L.M. . Influence of spot welding parameters on Al-Si coated 22MnB5 for automotive application. SAE Technical Paper, n. 2017-36-0225, p. 1-6, 2017. DOI: 10.4271/2017-36-0225

    Abstract: The application of press hardening steels (PHS) Al-Si coating has been increasing in body in white vehicles as an approach to meet the demands of safety and CO2 reduction regulations. The vehicle structures with PHS largely depend on the integrity and the mechanical performance of the spots weld. During the spot welding process, intermetallic phase may appear in function of the chemical composition of the steel and coating. One of these intermetallics is the Fe-Al phase which brittleness decreases the strength of the weld joint. In this study, resistance spot welding (RSW) experiments were performed in order to evaluate the influence of the welding parameters of single-lap joints PHS - 22MnB5 steel grade. Welded samples of the Al-Si coated PHS steel as received, i.e., before any heat treatment and stamping, were evaluated by means of glow discharge optical emission spectroscopy (GDOES) technique that allows a quick and accurate evaluation of the chemical composition profile along the spot weld thickness. The GDOES results showed that the squeeze welding parameter has the higher influence on cupper diffusion at the Al-Si-Fe layer. The pre-burn current and welding current showed the higher influences in Fe-Al diffusion. The pulse technique and post-heat treatment had had the lower influences in Fe-Al diffusion.

    Palavras-Chave: presses; hardening; steels; boron; coatings; silicon; aluminium; heat treatments

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  • IPEN-DOC 25013

    GOMES, MAURILIO P. ; SANTOS, IGOR ; COUTO, CAMILA ; MUCSI, CRISTIANO ; ROSSI, JESUALDO L. ; COLOSIO, MARCO. P/M valve seat inserts: air quenching and characterization. SAE Technical Paper, n. 2017-01-5014, 2017. DOI: 10.4271/2017-01-5014

    Abstract: This work consists of evaluating the influence of heat treatment on sintered valve seat insert (VSI) obtained with two different highspeed steels powders and one tool steel: AISI M3:2, AISI M2 and AISI D2, respectively. The high-speed / tool steel powders were mixed with iron powders and additives such as manganese sulphide, zinc stearate, graphite and niobium carbide. All the high-speed / tool steel powders had its particle size distribution and morphology analyzed. The heat treatment of the VSI consisted of air quenching followed by double tempering it in seven different and equidistant temperatures, ranging from 100 °C until 700 °C. A data acquisition system with a thermocouple type k attached to the samples was used to determine the air-quenching cooling rate. The mechanical and physical properties measurements were carried out, i.e., apparent density, apparent hardness and crush radial strength. The microstructural evaluation consisted of etching the VSI and then analyzing it using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results showed that the VSI obtained with the AISI M3:2 and M2 high-speed steel powders mixtures showed the best results regarding its apparent hardness and crush radial strength after air quenching and double tempering it at 600 °C.

    Palavras-Chave: alloys; heat treatments; steels; powders; valves; quenching

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  • IPEN-DOC 25012

    ROCHA, FLAVIO R. ; ANGELINI, MATHEUS ; HENRIQUES, HELOISE R. ; SOARES, JOSIANE S. ; SILVA, PAULO S.C. ; FAVARO, DEBORAH I.T. . Metal and trace element assessment in bottom sediments from medium Tietê River Basin, by INAA and ICP OES techniques. In: INTERNATIONAL NUCLEAR CHEMISTRY CONGRESS, 5th, August 27 - September 01, 2017, Gothenburg, Sweden. Abstract... 2017. p. 104-104.

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A pesquisa no RD utiliza os recursos de busca da maioria das bases de dados. No entanto algumas dicas podem auxiliar para obter um resultado mais pertinente.

✔ É possível efetuar a busca de um autor ou um termo em todo o RD, por meio do Buscar no Repositório , isto é, o termo solicitado será localizado em qualquer campo do RD. No entanto esse tipo de pesquisa não é recomendada a não ser que se deseje um resultado amplo e generalizado.

✔ A pesquisa apresentará melhor resultado selecionando um dos filtros disponíveis em Navegar

✔ Os filtros disponíveis em Navegar tais como: Coleções, Ano de publicação, Títulos, Assuntos, Autores, Revista, Tipo de publicação são autoexplicativos. O filtro, Autores IPEN apresenta uma relação com os autores vinculados ao IPEN; o ID Autor IPEN diz respeito ao número único de identificação de cada autor constante no RD e sob o qual estão agrupados todos os seus trabalhos independente das variáveis do seu nome; Tipo de acesso diz respeito à acessibilidade do documento, isto é , sujeito as leis de direitos autorais, ID RT apresenta a relação dos relatórios técnicos, restritos para consulta das comunidades indicadas.

A opção Busca avançada utiliza os conectores da lógica boleana, é o melhor recurso para combinar chaves de busca e obter documentos relevantes à sua pesquisa, utilize os filtros apresentados na caixa de seleção para refinar o resultado de busca. Pode-se adicionar vários filtros a uma mesma busca.

Exemplo:

Buscar os artigos apresentados em um evento internacional de 2015, sobre loss of coolant, do autor Maprelian.

Autor: Maprelian

Título: loss of coolant

Tipo de publicação: Texto completo de evento

Ano de publicação: 2015

✔ Para indexação dos documentos é utilizado o Thesaurus do INIS, especializado na área nuclear e utilizado em todos os países membros da International Atomic Energy Agency – IAEA , por esse motivo, utilize os termos de busca de assunto em inglês; isto não exclui a busca livre por palavras, apenas o resultado pode não ser tão relevante ou pertinente.

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

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✔ 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).

ATENÇÃO!

ESTE TEXTO "AJUDA" ESTÁ SUJEITO A ATUALIZAÇÕES CONSTANTES, A MEDIDA QUE NOVAS FUNCIONALIDADES E RECURSOS DE BUSCA FOREM SENDO DESENVOLVIDOS PELAS EQUIPES DA BIBLIOTECA E DA INFORMÁTICA.

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.

O Repositório Digital do IPEN é um equipamento institucional de acesso aberto, criado com o objetivo de reunir, preservar, disponibilizar e conferir maior visibilidade à Produção Científica publicada pelo Instituto, desde sua criação em 1956.

Operando, inicialmente como uma base de dados referencial o Repositório foi disponibilizado na atual plataforma, em junho de 2015. No Repositório está disponível o acesso ao conteúdo digital de artigos de periódicos, eventos, nacionais e internacionais, livros, capítulos, dissertações, teses e relatórios técnicos.

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.