Navegação por ano de publicação "2019"

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  • IPEN-DOC 25763

    QUEIROZ, FERNANDA M.; DONATUS, UYIME ; RAMIREZ, OSCAR M.P.; ARAUJO, JOAO V. de S. ; VIVEIROS, BARBARA V.G. de ; LAMAKA, SVIATLANA; ZHELUDKEVICH, MIKHAIL; MASOUMI, MOHAMMAD; VIVIER, VINCENT; COSTA, ISOLDA ; MELO, HERCILIO G. de. Effect of unequal levels of deformation and fragmentation on the electrochemical response of friction stir welded AA2024-T3 alloy. Electrochimica Acta, v. 313, p. 271-281, 2019. DOI: 10.1016/j.electacta.2019.04.137

    Abstract: The effect of unequal levels of deformation and fragmentation on the electrochemical response of friction stir welded AA2024-T3 has been investigated using electron backscatter diffraction, scanning electron microscopy, global and localized electrochemical techniques. The friction stir welding process introduced unequal distribution and fragmentation of coarse intermetallic particles, such that more clusters of these particles were present in the thermomechanically affected zone of the weld. This resulted in a higher susceptibility to severe localized corrosion in this region when compared with the others. Results from electrochemical measurements using a microcell could not be clearly correlated with the corrosion behaviour because no significant differences were observed using these techniques. On the other hand, LEIS and SVET results were in agreement and correlated with the corrosion evolution at the surfaces of the tested samples.

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  • IPEN-DOC 25760

    ALMEIDA, S.B. ; VILLANI, D. ; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L. . Dosimetric evaluation and comparation of TL responses of LiF:Mg,Ti and μLiF:Mg,Ti in the clinical electron beams dosimetry applied to total skin irradiation (TSEB) treatments. Radiation Measurements, v. 125, p. 15-18, 2019. DOI: 10.1016/j.radmeas.2019.03.007

    Abstract: The Total Skin Electron Beam (TSEB) irradiation is a radiotherapeutic technique that aims to provide the patient's skin surface with a more homogeneous dose, in order to treat cutaneous T-cell lymphomas, both for curative and palliative purposes. Electron irradiation penetrates a few millimeters into the skin, reaching the affected parts completely, without penetrating the internal organs. In vivo dosimetry has become an important role for the treatment of total skin irradiation within a rigorous quality assurance program that should be an integral part of the radiotherapy departments. The use of TLDs in vivo can identify variations in the prescribed dose because its measurement accuracy and great precision. The LiF:Mg,Ti is the most used TL material and widely studied in radiotherapy dosimetry due to near tissue-equivalence of the material, along with its overall reliability. The dosimeters of μLiF:Mg,Ti have been gaining considerable importance in the radiotherapy departments. These detectors allow measurements in vivo with great advantages due to their minimum dimensions of 1×1×1 mm3. 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 in several TSEB parameter tests and in clinical application were evaluated, analyzing the dose distribution in a treatment simulation using AldersonRando anthropomorphic phantom. The results showed that the μLiF:Mg,Ti presented greater variation of the response in relation to LiF dosemeters in some parameters analyzed, due to the small dimensions and to evaluate doses absorbed in the surface over a large area in the treatment plan.

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  • IPEN-DOC 25759

    GONCALVES, J.A.C. ; BARROS, V.S.M.; ASFORA, V.K.; KHOURY, H.J.; BUENO, C.C. . Diagnostic x-ray dosimeters using standard float zone (FZ) and XRA-50 commercial diodes. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.592

    Abstract: The results obtained with a standard float zone (FZ) silicon diode, processed at the Helsinki Institute of Physics, used as on-line diagnostic X-ray dosimeter are described in this work. The device was connected in the short-circuit current mode to the input of an integrating electrometer. The response repeatability and the current sensitivity coefficient of the diode were measured with diagnostic X-ray beams in the range of 40-80 kV. The dose-response of the device, evaluated from 10 mGy up to 500 mGy, was linear with high charge sensitivity. Nevertheless, significant energy dependence was observed in the charge sensitivity of FZ device for energies below 70 kV. The dosimetric characteristics of this FZ diode were compared to those of an XRA-50 commercial Si diode, specially designed to X-ray dosimetry. The results obtained with the FZ diode evidenced that it can be an alternative choice for diagnostic X-ray dosimetry, although it needs to be calibrated for individual X-ray beam energies. The studies of long-term stability and the radiation hardness of these diodes are under way.

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  • IPEN-DOC 25758

    SOMESSARI, S.L. ; MOURA, J.A. ; CALVO, W.A.P. . Development of an automated system for the operation of an electron beam accelerator. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-12, 2019. DOI: 10.15392/bjrs.v7i2A.593

    Abstract: Electron beam accelerators are used in many applications, such as basic physical research, chemistry, medicine, molecular biology, microelectronics, agriculture and industry, among others. The majority of the accelerators have electrons from a hot tungsten filament and their energy is increased as it passes through an electric field in the vacuum chamber. For industrial purposes, the most common model is Dynamitron®. At IPEN-CNEN/SP, there is an electron beam accelerator Dynamitron® Type (Manufactured by RDI - Radiation Dynamics Inc., 1978) model DC1500/25/4. The technology applied was available in the 60´s and 70´s, but, nowadays is obsolete. Moreover, there are not original spare parts for this equipment any longer. The aim of this work is to develop a nationalized automated operation system for the accelerator, to replace the old equipment and allow extending the useful life of the accelerator for around ten years.

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  • IPEN-DOC 25757

    LIMA, N.P. ; SAIKI, M. . Determination of uranium in tree bark samples by epithermal neutron activation analysis. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-11, 2019. DOI: 10.15392/bjrs.v7i2A.574

    Abstract: In this study uranium (U) concentrations were determined in certified reference materials (CRMs) and in tree bark samples collected in “Cidade Universitária Armando de Salles Oliveira” (CUASO) USP, São Paulo. CRMs were analyzed using the experimental conditions used for barks for analytical quality control of U determina-tion. The barks were collected from different species namely Poincianella pluviosa and Tipuana tipu. These bark samples were cleaned, dried, grated and milled for the analyses by epithermal neutron activation analysis meth-od (ENAA). This method consists on irradiating CRMs, samples and U standard in IEA-R1 nuclear reactor with thermal neutron flux of 1.9 x 1012 n cm-2 s-1 during 40 to 60 seconds depending on their matrices. The U was iden-tified, using gamma-ray spectrometry, by the peak of 74.66 keV of 239U with half-life of 23.47 minutes. Concen-tration of U was calculated by comparative method. Results obtained for CRMs presented good precision and accuracy, with |Z score| ≤ 0.39. Uranium concentrations in tree barks varied from 83.1 to 627.6 ng g-1 and the relative standard deviations of these results ranged from 1.8 to 10 %.

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  • IPEN-DOC 25756

    TEIXEIRA, LUIZ F.L. ; MAZZILLI, BARBARA P. . Determination of uranium and thorium in sediments from Cananéia‑Iguape system, Brazil. Journal of Radioanalytical and Nuclear Chemistry, v. 320, n. 3, p. 551-560, 2019. DOI: 10.1007/s10967-019-06528-3

    Abstract: The Cananéia-Iguape system is a complex of lagoon and estuarine channels located in the south of state of São Paulo. This system received the waters of Ribeira de Iguape River, after the construction of a channel in 1852, which changed its original characteristic. This study evaluated the uranium and thorium concentrations in superficial bottom sediments samples from this system by spectrophotometric determination. The mean uranium concentration found was 2.9 mg kg−1 and 6.6 mg kg−1 for thorium. Geo-accumulation index classified the sediments as “unpolluted to moderately polluted”. Statistical analysis showed that uranium and thorium presented a non-homogeneous behavior along the system.

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  • IPEN-DOC 25755

    STEFANI, GIOVANNI L. de ; MOREIRA, JOAO M.L.; MAIORINO, JOSE R.; ROSSI, PEDRO C.R.. Detailed neutronic calculations of the AP1000 reactor core with the Serpent code. Progress in Nuclear Energy, v. 116, p. 95-107, 2019. DOI: 10.1016/j.pnucene.2019.03.030

    Abstract: In this work we present some validation results for reactor core modeling with the Serpent code performed for the first cycle of the AP1000 reactor. The comparison with reported values of the assembly k∞ for cold zero-power condition showed a discrepancy of 0.29%. The kef for full-core static and burnup calculations of the very heterogeneous AP1000 reactor core also presented good agreement with reported values. The kef for states with uniform fuel and moderator temperature distributions showed discrepancies below 0.91%. The boron worth curve obtained from burnup calculations with the Serpent code model results reproduced very well literature results despite using uniform temperature distributions in the modeling. In addition we discuss shadowing effects among burnable absorber rods (IFBA and Pyrex) and control rods which are, together with soluble boron, the control means throughout the first cycle. For instance, the presence of 9 Pyrex rods in an assembly decreased the average reactivity worth of one IFBA rod from 147 pcm to 33 pcm; and the presence of 28 IFBA rods in an assembly decreased the average reactivity worth of one Pyrex rod from 631 pcm to 277 pcm. The reactivity worth of a black control rod reduces about 20% when 28 IFBA rods are inserted in the fuel assembly.

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  • IPEN-DOC 25754

    CAVALIERI, TASSIO A. ; SIQUEIRA, PAULO T.D. ; SHORTO, JULIAN M.B. ; GENEZINI, FREDERICO A. ; YORIYAZ, HELIO . Design, fabrication and modeling of an AmBe neutron irradiator for TLD screening for neutron dose measurement in mixed radiation fields. Applied Radiation and Isotopes, v. 150, p. 31-38, 2019. DOI: 10.1016/j.apradiso.2019.05.009

    Abstract: TLDs dosimeters are frequently presented as a viable choice for dosimetric studies when dealing with mixed neutron-gamma radiation fields. However, this choice is not without some drawbacks, because not only TLD response is highly dependent on particle type but also on neutron energy spectrum. Therefore, a correct screening and calibration of the dosimeter are required, and a simple shift from gamma screening methodology for mixed field is not suitable. This paper presents the design, fabrication and tests of an irradiator for TLD screening for neutron dose measurement using an AmBe source and polyethylene as moderator material. The design of the irradiator was conducted through Monte Carlo simulations using the MCNP5 code. The experimental validation and tests were performed using Indium activation foils and TLD 600 dosimeters. The manufactured irradiator demonstrated to be suitable for TLD screening under neutron source radiation field, offering very good homogeneity conditions in the radiation field so to guarantee same radiation dose delivered to the TLDs.

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  • IPEN-DOC 25753

    FERREIRA, T.S. ; CARVALHO, F.M.S.; GUEDES-SILVA, C.C. . Densification and microstructure of Si3N4-TiN ceramic composites. Cerâmica, v. 65, 1, p. 87-91, 2019. DOI: 10.1590/0366-6913201965S12605

    Abstract: Silicon nitride is a ceramic material widely used in various structural applications at high temperatures owing to its excellent combination of mechanical and thermal properties. To increase the application of Si3N4, many researches have been developed to improve its fracture toughness and processing conditions. In this study, the sintering and microstructure of Si3N4-TiN composites, containing Al2O3 and Y2O3 as sintering aids, were studied. Samples were obtained by the conventional method of mixing powders and sintered at 1750 ºC/1 h and 1815 ºC/1 h under nitrogen atmosphere. Density values of the samples were determined by the Archimedes method, reaching values between 96.9% and 98.0% of theoretical density, with a porosity of less than 0.5%. The sintered samples were analyzed by X-ray powder diffraction and scanning electron microscopy. The results showed the materials reached high fracture toughness, low hardness and a microstructure with TiN grains dispersed in a β-Si3N4 matrix containing an amorphous intergranular phase.

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  • IPEN-DOC 25752

    TERADA, M. ; QUEIROZ, F.M.; AGUIAR, D.B.S.; AYUSSO, V.H. ; COSTENARO, H.; OLIVIER, M.G.; MELO, H.G. de; COSTA, I. . Corrosion resistance of tartaric-sulfuric acid anodized AA2024-T3 sealed with Ce and protected with hybrid sol–gel coating. Surface & Coatings Technology, v. 372, p. 422-426, 2019. DOI: 10.1016/j.surfcoat.2019.05.028

    Abstract: 2024 aluminum alloys are widely used in the aerospace industry due to properties as lightweight, high specific strength and durability. However, they are prone to localized corrosion due to its high amount of intermetallics. A promising method to protect the exposed metal surface is to use eco-friendly alternative corrosion inhibitors in combination with a barrier coating system. In this study, a treatment in an aqueous solution with the addition of cerium ions has been proposed and its effects on the corrosion resistance of the AA2024-T3 alloy were investigated. Samples were anodized, hydrothermally treated in aqueous solutions, containing or not cerium ions at the boiling temperature and then coated with sol-gel. The effect of Ce ions in the characteristics of the surface film formed, such as morphology and corrosion resistance, was investigated by scanning electron microscopy and electrochemical impedance spectroscopy (EIS). The EIS results showed that the addition of Ce(III) ions improved the corrosion resistance of the AA 2024-T3 TSA anodized and hydrothermally treated.

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  • IPEN-DOC 25751

    CUNHA, J.S.; SANTOS, W.S. ; CARVALHO JUNIOR, A.B.. Conversion Coefficients of equivalent and effective doses in terms of air kerma for computational scenarios of Total Body Irradiation in lying-down patients. Radiation Physics and Chemistry, v. 159, p. 138-146, 2019. DOI: 10.1016/j.radphyschem.2019.02.051

    Abstract: This study aimed to calculate the Conversion Coefficients (CC) of Equivalent and Effective doses by air kerma considering Total Body Irradiation scenarios with Varian linear accelerator with photon beams energy of 4, 6, 10, 15, 18, and 25 MV. The simulations were performed in the MCNPX code and the University of Florida (UF) phantoms were used to represent exposed lying down adult patients in the AP, PA, RLAT, and LLAT irradiation geometries. Lead attenuators were inserted in the scenarios for the preservation of organs of risk and their contribution were analyzed for CC. For most counts, the statistical uncertainty was approximately 5%. For the gonads, CC values for the male phantom decreased with the increase of energy in the AP geometry, which did not occur for the female phantom. As the beam becomes more penetrating, the ovary absorbs more energy because of its internal position. Considering the lung, an organ of risk in TBI, the insertion of the attenuators in the scenarios caused the CC values to reduce by more than 30%. For organs and tissues such as skin and male breasts, the attenuators caused the dose to increase. As for the active bone marrow, which is the TBI target tissue, it was not possible to obtain a good estimate for CC at 15, 18, and 25 MV due to a limitation of the method used to calculate the dose in the bone areas. Nevertheless, for lower energies the CC values for the marrow were valid.

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  • IPEN-DOC 25750

    ARMELIN, M.J.A. ; MAIHARA, V.A. ; COZZOLINO, S.M.F.; SILVA, P.S.C. ; SAIKI, M. . Concentrations of Se, Ba, Zn and Mn in Brazil nuts. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-10, 2019. DOI: 10.15392/bjrs.v7i2A.701

    Abstract: The concentrations of Se, Ba, Zn and Mn were determined in samples of Brazil nuts collected in two ways: a) in a production farm predominantly for export and, b) in various points of sale from different regions of Brazil. Instrumental neutron activation analysis was the analytical technique used in this study. Results indicate that the concentrations of Se and Ba varied greatly among the Brazil nut samples analyzed. This large variability may be related to the soil characteristics from which the nuts were produced. An inverse correlation was observed between the concentrations of Se and Ba. On the other hand, the concentrations of Zn and Mn did not show significant differences among these samples.

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  • IPEN-DOC 25749

    MILAGRE, MARIANA X. ; DONATUS, UYIME ; MACHADO, CARULINE S.C. ; ARAUJO, JOAO V.S. ; SILVA, REJANE M.P. da ; VIVEIROS, BARBARA V.G. de ; ASTARITA, ANTONELLO; COSTA, ISOLDA . Comparison of the corrosion resistance of an Al–Cu alloy and an Al–Cu–Li alloy. Corrosion Engineering, Science and Technology, v. 54, n. 5, p. 402-412, 2019. DOI: 10.1080/1478422X.2019.1605472

    Abstract: In this study, the corrosion mechanisms of the AA2024-T3 and the AA2098-T351 were investigated and compared using various electrochemical techniques in 0.005 mol L−1 NaCl solution. The severe type of corrosion in the AA2098-T351 was intragranular attack (IGA) although trenching and pitting related to the constituent particles were seen. On the other hand, the AA2024-T3 exhibited severe localised corrosion associated with micrometric constituent particles, and its propagation was via grain boundaries leading to intergranular corrosion (IGC). Electrochemical techniques showed that the corrosion reaction in both alloys was controlled by diffusion. The non-uniform current distribution in both alloys showed that EIS was not a proper technique for comparing the corrosion resistance of the alloys. However, local electrochemical techniques were useful for the evaluation of the corrosion resistance of the alloys.

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  • IPEN-DOC 25748

    SOUZA, ELIEL S. ; SILVA, PAULO S.C. . Co adsorption in kaolinite. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-15, 2019. DOI: 10.15392/bjrs.v7i2A.658

    Abstract: Adsorption of metal ions in clay minerals has been used as an alternative to water and effluents treatment. Kao-linite is a clay mineral that presents low specific surface area and exchange ion capacity. Nevertheless, structural modifications can be achieved by means of acid or thermal activation. In this paper, it was studied the surface area of kaolinite/bentonite, kaolinite/activated carbon mixtures, thermal activated kaolinite and thermal activat-ed kaolinite/activated carbon mixture. The mixture of kaolinite/activated carbon was tested for pH, contact time, interfering ions and initial concentration effects in the cobalt adsorption. Results showed that the optimized pa-rameters are pH 6 and contact time of 30 min. Chromium acted as a competitive ion, zinc does not appear to have affected adsorption while iron seems to have favored it. Langmuir and Freundlich isotherms indicated that the adsorption of Co in the mixture of kaolinite/activated carbon is a spontaneous process.

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  • IPEN-DOC 25747

    CARVALHO, P.R. ; MUNITA, C.S. ; NEVES, E.G.; ZIMPEL, C.A.. Chemical characterization of ancient pottery from the south-west Amazonia using Instrumental Neutron Activation Analysis. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-14, 2019. DOI: 10.15392/bjrs.v7i2A.619

    Abstract: The analyzes carried out in this work aims to contribute to the discussion about the ceramic objects founded in Monte Castelo’s sambaqui located at south-west Amazonia. The first study accomplished by Miller in 1980 suggests that this archaeological site is inserted in the oldest contexts of production of ceramics in the Amazon. Until today, there aren't any physical and chemical analysis performed in this ceramics and this kind of studies may help archaeological researches at the sambaqui. This work presents a preliminary study of chemical characterization of eighty-four ceramic samples using instrumental neutron activation analysis (INAA) by means of the determination of Na, K, La, Sm, Yb, Lu, U, Sc, Cr, Fe, Co, Zn, Rb, Cs, Ce, Eu, Hf and Th. With the purpose to study the similarity/dissimilarity between the samples, cluster and discriminant analysis were used. The results showed the existence of three different chemical groups whose dating ranging 3000 b.P. to 1500 b.P. that are in agreement with the archaeological studies made by Miller and suggest Bacabal’s phase as the oldest ceramist culture in the Southwest of the Amazon.

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  • IPEN-DOC 25746

    PEREIRA, MARIA da C.C. ; FILHO, TUFIC M. ; BERRETTA, JOSE R. ; TOMAZ, LUCAS F. ; PINTO, MARLENE C. . Characteristics of Pb2+ doped CsI matrix under gamma and neutron excitations. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-13, 2019. DOI: 10.15392/bjrs.v7i2A.595

    Abstract: In recent years, there has been an increasing interest in finding new fast scintillating material or improve the characteristics of known scintillators for the demand of high energy physics, industrial and nuclear medical ap-plications. Divalent lead ions Pb2+ built in some crystal structures are efficient emission centers and their appli-cations in scintillators were and are still the reason of an intensive study of emission properties of different com-pounds containing these ions. In this context, the crystals of Pb2+ doped CsI matrix were grown by the vertical Bridgman technique and subjected to annealing in vacuum of 10-6 mbar and constant temperature of 350°C, for 24 hours, and then they were employed. To evaluate the response of the CsI:Pb scintillator crystal to gamma radiation, radioactive sources of 137Cs (662 keV), 60Co (1173 keV and 1333 keV), 22Na (511 keV and 1275 keV) and 133Ba (355 keV) were used. The operating voltage of the photomultiplier was 2700 V for the detection of gamma rays and the accumulation time in the counting process was 600 s. The scintillator response to neutron radiation from a radioactive source of AmBe with energy range of 1 to 12 MeV was available. The activity of the AmBe source was 1 Ci Am. The emission rate was 2.2 x 106 neutrons / second. The operating voltage of the pho-tomultiplier tube was 1300 V. The accumulation time in the counting process was 600 s. With the results obtai-ned, it may be observed that the crystals are sensitive to these radiations.

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  • IPEN-DOC 25742

    COSTA, PRISCILA ; RAELE, MARCUS P. ; MACHADO, NOE G.P. ; SILVA, ANDRE F. ; VIEIRA JUNIOR, NILSON D. ; GENEZINI, FREDERICO A. ; SAMAD, RICARDO E. . Boron film laser deposition by ultrashort pulses for use as neutron converter material. Applied Physics A, v. 125, n. 2, p. 1-8, 2019. DOI: 10.1007/s00339-019-2382-6

    Abstract: This study investigated the production of boron films by femtosecond pulsed laser deposition (PLD) to be used as converters on bulk semiconductor neutron detectors. The ablation threshold of metallic boron was determined and the film growth was studied as a function of deposition time (5–90 min) and laser pulse energy (35–530 μJ). The films were characterized by scanning electron microscopy (SEM), revealing a flaky morphology, optical profilometry, which determined the films thicknesses (from 80 nm up to 4 μm), Ion Beam Analysis (IBA) that assessed their elemental composition and X-ray diffraction (XRD), which revealed an amorphous structure. In addition, a thermal load study was performed to evaluate the heat flux onto the substrate during deposition process. Stable boron films obtained show that the femtosecond PLD process is reliable and reproducible for the fabrication of thick boron coatings.

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  • IPEN-DOC 25741

    PECORARO, GIULLIANA D.; HORTELLANI, MARCOS A. ; HAGIWARA, YURI S.; BRAGA, ELISABETE S.; SARKIS, JORGE E. ; AZEVEDO, JULIANA S.. Bioaccumulation of total mercury (THg) in catfish (Siluriformes, Ariidae) with different sexual maturity from Cananéia-Iguape estuary, SP, Brazil. Bulletin of Environmental Contamination and Toxicology, v. 102, n. 2, p. 175-179, 2019. DOI: 10.1007/s00128-018-2485-3

    Observação: Correction anexado. Bulletin of Environmental Contamination and Toxicology, v. 102, p. 180, 2019. DOI: 10.1007/s00128-018-2507-1

    Abstract: In order to improve the knowledge of total mercury (THg) bioaccumulation in bioindicator species of sea catfish (Siluriformes, Ariidae) and taking into account the relatively recent approach with respect to estuarine fish on the Brazilian coast, 65 individuals were caught in the northern and southern regions of the Cananeia estuary to determine the concentration of the THg in muscles, gills, gonads and kidney of the Cathorops spixii and Genidens genidens specimens. The difference in the THg accumulation associated to the maturity of the catfish reflects a differential metabolism regarding THg bioaccumulation in adults (males and females) and juveniles. These observations reinforce the importance of considering the maturity of the individual in order to understand the bioaccumulation and metabolism of fish under different environmental stress and conditions. Furthermore, abiotic conditions such as salinity should be evaluated in association with metabolic/biological conditions of the fish’s bioindicators, especially in environments with large natural or anthropogenic transition gradients.

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  • IPEN-DOC 25740

    TORRECILHA, J.K. ; LAZZERINI, F.T.; SILVA, P.S.C. . Bentonite and montmorillonite maturation with Águas de Lindóia, Peruíbe and Poços de Caldas waters. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-16, 2019. DOI: 10.15392/bjrs.v7i2A.670

    Abstract: This study aims to characterize the artificial peloid obtained by maturing bentonite and montmorillonite with Águas de Lindóia, Poços de Caldas and Peruíbe water for three months. The pH, moisture, organic matter content, loss on ignition and swelling power of matured and non-matured samples were measured for physicochemical characterization. The elemental concentration was determined by instrumental neutron activation analysis. Results showed that pH, moisture (%) and LOI (%) at 1000 ºC did not change after maturation for all samples and an increase in the organic matter (%) was noted for all samples, mainly in the peloids treated with Peruíbe sea water. The concentration of As, Ba, Br, Ca, Ce, Co, Cr, Cs, K, La, Na, Yb and Zn has changed after the maturation process in both clays and the Br and Na concentration has changed in both clays when matured with sea water from Peruíbe.

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  • IPEN-DOC 25739

    NISTI, M.B. ; SAUEIA, C.H.R. ; CASTILHO, B. ; MAZZILLI, B.P. . Assessment of Sr-90 in water samples: precision and accuracy. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-12, 2019. DOI: 10.15392/bjrs.v7i2A.559

    Abstract: The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of 90Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using 90Sr standard solutions.

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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.