Navegação Periódicos - Artigos por ano de publicação "2018"

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  • IPEN-DOC 25649

    PIVA, AMANDA M. da; TRIBST, JOAO P.; GONDIM, LAISA D.; RIBEIRO, ISABELLA L.; CAMPOS, FERNANDA; ARATA, ANELYSE ; SOUZA, RODRIGO O.. Y-TZP surface behavior under two different milling systems and three different accelerated aging protocols. Minerva Stomatologica, v. 67, n. 6, p. 237-245, 2018. DOI: 10.23736/S0026-4970.18.04138-9

    Abstract: BACKGROUND: To evaluate the influence of aging and milling system on zirconia surface roughness (SR) and phase transformation. METHODS: Eighty crowns were divided in two groups according to yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramic milling system (CAD-Neodent or MAD-Zirkonzahn). The crowns were submitted to different aging protocols (N.= 10): 1) no aging; 2) autoclaving; 3) pH cycling; or 4) thermocycling. Next, the samples were submitted to an optical profilometry analysis to determine differences in the SR (mu m). An X-ray diffraction analysis (XRD) was performed to quantify the percentage of monoclinic phase transformation. SR data was analyzed by two-way ANOVA (alpha=0.5%). RESULTS: Aging protocol (P=0.42) and milling system (P=0.08) had no influence on the SR. However, the number of monoclinic phases was influenced by the autoclaving and pH cycling. CONCLUSIONS: The surface roughness of zirconia-based crowns was not influenced by low temperature degradation or milling system. Regarding the phase transformation, autoclaving and pH-cycling aging presented a monoclinic phase increase when compared to the control group and thermocycled groups.

    Palavras-Chave: teeth; surface properties; dentistry; milling; yttrium; yttrium oxides; zirconium oxides; implants; biological recovery; ceramics; x-ray diffractometers; computer codes; computer-aided design; computer-aided manufacturing; manufacturing; autoclaves

  • 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

  • IPEN-DOC 24860

    BATISTA, R.M. ; NARANJO, J.F.R.; MUCCILLO, E.N.S. . A versatile software for construction of the master sintering curve. Materials Science Forum, v. 912, p. 240-244, 2018. DOI: 10.4028/

    Abstract: Several models have been developed over the last years to study the microstructure development of ceramic and metal powders during sintering. Among the most utilized methodology one may find the Arrhenius and the so-called Master Sintering Curve (MSC). Both models involve manipulation of a large number of data, and repetitive and time-consuming calculations. In this work, was developed a versatile and friendly-user software for a PC-type computer encompassing both methodologies. The software is flexible allowing for kinetic data evaluation such as the activation energy for sintering and sintering maps. Details of the software along with its application to investigate the sintering process of 10 mol% gadolinia-doped ceria are described.

    Palavras-Chave: sintering; computer codes; simulation; ceramics; gadolinium; cerium oxides; doped materials; fuel cells

  • IPEN-DOC 24777

    PEREIRA, DAISA L. ; FREITAS, ANDERSON Z. ; BACHMANN, LUCIANO; BENETTI, CAROLINA; ZEZELL, DENISE M. ; ANA, PATRICIA A.. Variation on molecular structure, crystallinity, and optical properties of dentin due to Nd:YAG laser and fluoride aimed at tooth erosion prevention. International Journal of Molecular Sciences, v. 19, n. 2, 2018. DOI: 10.3390/ijms19020433

    Abstract: This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.

    Palavras-Chave: molecular structure; dentin; abrasion; demineralization; crystallography; fluorides; neodymium lasers; laser radiation; erosion; teeth; dentistry; infrared radiation

  • 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

  • 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

  • IPEN-DOC 24770

    ORTIZ, NILCE ; SILVA, ANDRE; LIMA, GISELLE N.S. ; HYPPOLITO, FERNANDA P. . Using solar-TiO2 and biocarbon to decompose and adsorb amoxicillin from polluted waters. International Journal of Chemistry, v. 10, n. 1, p. 131-136, 2018. DOI: 10.5539/ijc.v10n1p131

    Abstract: Surface water discharge of domestic sewage poses a treat mostly due to antibiotics content as amoxicillin. Its environmental presence provides the bacterial resistance enhancement and disturbance in aquatic life. The biocarbon is an organic carbon compound obtained by biomass pyrolisis at 300oC to 750oC under low oxygen environment. It is an effective adsorbent derived from agricultural and industrial solid biomass also frequently used to remove various pollutants, including dyes, pesticides, organic compounds and heavy metals from aqueous solutions. The importance of this natural material rises as low cost abundant and renewable alternative to activated carbon used on wastewater treatment application. Several technologies are employed to modify crude precursors on biocarbon preparation including chemical, physical and biological treatments with the addition of functional groups. The raw biomass material also provides some radicals and humic acids with promising water adsorbent results. The integrated process of the efficient Solar-TiO2photodecomposition followed by biocarbon adsorption resulted on 94% of amoxicillin removal percentage and avoids the toxic treatment sludge production.

    Palavras-Chave: surface waters; sewage; antibiotics; waste water; adsorption; carbon; biofuels; biomass; water pollution

  • IPEN-DOC 24822

    WEBLER, G.D.; RODRIGUES, W.C.; SILVA, A.E.S.; SILVA, A.O.S.; FONSECA, E.J.S.; DEGENHARDT, M.F.S.; OLIVEIRA, C.L.P.; OTUBO, L. ; BARROS FILHO, D.A.. Use of micrometric latex beads to improve the porosity of hydroxyapatite obtained by chemical coprecipitation method. Applied Surface Science, v. 436, p. 141-151, 2018. DOI: 10.1016/j.apsusc.2017.11.218

    Abstract: Hydroxyapatite is one of the most important biomaterials whose application mainly extends to implants and drug delivery. This work will discuss the changes in the pore size distribution of hydroxyapatite when there are latex beads present during the synthesis. These changes were monitored using different techniques: small angle X-ray scattering, X-ray diffraction, thermal gravimetrical analysis, N2 adsorption, scanning and transmission electron microscopy. Latex beads and hydroxyapatite form a single nanocomposite with well-distinguished inorganic and organic phases. Latex bead removal in the temperature range of 300–600 ◦C did not modify the original crystalline structure of hydroxyapatite. However, the latex beads favored an increase in the adsorption capacity of mesopores at temperatures higher than their glassy transition (Tg). The main result of this research work consists on the increase of surface area and pore size distribution obtained after the removal of latex beads template. Latex beads have been used in a different approach changing the porosity of hydroxyapatite scaffolds not only introducing new routes for cell integration but also broadening the pore size distribution which can result in a more high efficiency for drug release in living cells.

    Palavras-Chave: apatites; hydroxy compounds; biological materials; composite materials; surface properties; chemical reactions; synthesis

  • IPEN-DOC 25584

    ROSSETTI, DILCE R.; GRIBEL, ROGERIO; TOLEDO, PETER M.; TATUMI, SONIA H.; YEE, MARCIO; TUDELA, DIEGO R.G.; MUNITA, CASIMIRO S. ; COELHO, LUIZ de S.. Unfolding long-term Late Pleistocene–Holocene disturbances of forest communities in the southwestern Amazonian lowlands. Ecosphere, v. 9, n. 10, p. e02457-1 - e02457-32, 2018. DOI: 10.1002/ecs2.2457

    Abstract: Linking the distribution of plant species to geology has generally been biased by the oversimplification of landscape evolution and the lack of understanding of complex geological processes. The Amazonian lowlands have forests in different successional stages, and a growing perception is that such heterogeneity results from long-term environmental changes. This hypothesis is investigated by designing an analytical model based on past and present-day vegetation and successions of the plant communities, combined with an advanced understanding of geological history. An area of southwestern Amazonia was selected for floristic inventories, and we interpreted the paleovegetation based on C/N and d13C analyses of sedimentary organic matter. These data were examined in the context of the geological evolution on the basis of new sedimentological and chronological data. The topographically high Late Pleistocene deposits had continuous and highly diversified late-successional terra firme forests as well as local fluvial paleolandforms of younger ages with less diversified campinarana forests. Late Pleistocene–Holocene terrains in intermediate elevations had terra firme forests, but shorter trees with lower basal areas and ecotonal forests appeared near the confines of the forest–savanna, while Holocene deposits recorded only seasonally flooded varzea forests. Several deposits of Late Pleistocene and Late Pleistocene–Holocene age recorded an expansion of C4 terrestrial plants before the establishment of the forest from ~20,000 cal yr BP to 7578 cal yr BP, which is not related to past arid episodes. We recorded forests with onsets at 6130–3533 cal yr BP, 3402–2800 cal yr BP, and 1624–964 cal yr BP to terra firme, varzea, and ecotonal forests, respectively. However, not all forests have reached maturity stages due to their location on terrains with a diverse history of terrace downcutting and deposition, which had a direct impact on local hydrology with the interaction of topographic gradients. The hydrology of the study area was also controlled by the distance from the main river valley. Capturing long-term disturbances over this region of still pristine forests may help elucidate the potential mechanisms that also determine trends in tree growth and forest diversity in other Neotropical regions.

    Palavras-Chave: geologic history; pleistocene epoch; natural occurrence; forests; ecosystems; quaternary period; sedimentary basins; luminescence; radioisotopes; amazon river

  • IPEN-DOC 25153

    BORGES, EDUARDO M. ; SABUNDJIAN, GAIANE ; DAURIA, FRANCESCO; PETRUZZI, ALESSANDRO. Uncertainty calculation in small break LOCA in the emergency core cooling system connected to the hot leg of Angra 2 nuclear power plant. International Journal of Nuclear Energy Science and Technology, v. 12, n. 2, p. 139-160, 2018.

    Abstract: Owing to the occurrence of nuclear accidents, worldwide nuclear regulatory organisations included the analysis of accidents considered as design basis accidents – Loss of Coolant Accident (large and small-break, LBLOCA or SBLOCA) – in the safety analysis reports of nuclear facilities. In Brazil, the tool selected by the licensing authority, Comissão Nacional de Energia Nuclear (CNEN), is RELAP5 Code. The aim of this paper is the evaluation of the performance of the Emergency Core Cooling System (ECCS) of Angra 2 nuclear reactor during SBLOCA. In this study, the RELAP5 code and the Code Internal Assessment of Uncertainty (CIAU) were used to simulate and analyse the uncertainties of the results. The postulated accident is the SBLOCA in the hot leg connected to the ECCS described in the Final Safety Analysis Report of Angra 2 (FSAR/A2). The results from this study were satisfactory when compared with the FSAR/A2.

    Palavras-Chave: reactor safety; regulations; power reactors; international regulations; loss of coolant; sbloca; lbloca; computer codes; radiation protection; eccs; safety analysis; risk assessment; angra-2 reactor

  • 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

  • IPEN-DOC 24811

    ZAMPIVA, RUBIA Y.S.; ACAUAN, LUIZ H.; VENTURINI, JANIO; GARCIA, JOSE A.M.; SILVA, DIEGO S. da ; HAN, ZHAOHONG; KASSAB, LUCIANA R.P.; WETTER, NIKLAUS U. ; AGARWAL, ANURADHA; ALVES, ANNELISE K.; BERGMANN, CARLOS P.. Tunable green/red luminescence by infrared upconversion in biocompatible forsterite nanoparticles with high erbium doping uptake. Optical Materials, v. 76, p. 407-415, 2018. DOI: 10.1016/j.optmat.2018.01.004

    Observação: Corrigendum anexado. Optical Materials, v. 84, p. 899, 2018. DOI: 10.1016/j.optmat.2018.05.080

    Abstract: Nanoparticles represent a promising platform for diagnostics and therapy of human diseases. For biomedical applications, these nanoparticles are usually coated with photosensitizers regularly activated in a spectral window of 530–700 nm. The emissions at 530 nm (green) and 660 nm (red) are of particular interest for imaging and photodynamic therapy, respectively. This work presents the Mg2SiO4:Er3+ system, produced by reverse strike co-precipitation, with up to 10% dopant and no secondary phase formation. These nanoparticles when excited at 985 nm show upconversion emission with peaks around 530 and 660 nm, although excitation at 808 nm leads to only a single emission peak at around 530 nm. The direct upconversion of this biomaterial without a co-dopant, and its tunability by the excitation source, renders Mg2SiO4:Er3+ nanoparticles a promising system for biomedical applications.

    Palavras-Chave: nanoparticles; biological materials; luminescence; erbium; doped materials; raman spectra; x-ray diffraction; raman spectroscopy; photoluminescence; scanning electron microscopy

  • IPEN-DOC 24818

    IZIDORO, JULIANA de C. ; MIRANDA, CAIO da S. ; GUILHEN, SABINE N. ; FUNGARO, DENISE A. ; WANG, SHAOBIN. Treatment of coal ash landfill leachate using zeolitic materials from coal combustion by-products. Advanced Materials and Technologies for Environmental Applications, v. 2, n. 1, p. 177-186, 2018.

    Abstract: Three different zeolitic materials derived from coal combustion by-products (CCBs) were used to treat local coal ash landfill leachate at the same power plant. The zeolitic materials properties were characterized in terms of mineralogical composition (XRD), chemical composition (XRF), total carbon content, morphological analysis (SEM), specific surface area (BET method), cation exchange capacity (CEC), loss of ignition, pH, conductivity and bulk density. XRD indicated that sodalite zeolite was formed in all the samples after hydrothermal activation of CCBs. One zeolitic product from baghouse fly ash (ZFB) presented the lowest SiO2/Al2O3 ratio, highest CEC and specific surface area, thus having a high capacity in removal of heavy metal pollutants. The zeolitic products were efficient to reduce arsenic concentration to a value below the legislation. All zeolitic materials also showed a significant removal of Ni, Cd, Zn and Co except of Cr at a dose of 10 g L-1. Thus, this work provides a sustainable strategy to resolution of solid waste from power plants.

    Palavras-Chave: coal; fly ash; sanitary landfills; leachates; combustion; zeolites; waste water; water treatment; chemical composition

  • IPEN-DOC 25199

    BRITO, TARCISIO; JULIO, ALISON; BERNI, MATEUS; PONCIO, LISIANE de C.; BERNARDES, EMERSON S. ; ARAUJO, HELENA; SAMMETH, MICHAEL; PANE, ATTILIO. Transcriptomic and functional analyses of the piRNA pathway in the Chagas disease vector Rhodnius prolixus. PLOS Neglected Tropical Diseases, v. 12, n. 10, p. e0006760-1 - e0006760-20, 2018. DOI: 10.1371/journal.pntd.0006760

    Abstract: The piRNA pathway is a surveillance system that guarantees oogenesis and adult fertility in a range of animal species. The pathway is centered on PIWI clade Argonaute proteins and the associated small non-coding RNAs termed piRNAs. In this study, we set to investigate the evolutionary conservation of the piRNA pathway in the hemimetabolous insect Rhodnius prolixus. Our transcriptome profiling reveals that core components of the pathway are expressed during previtellogenic stages of oogenesis. Rhodnius' genome harbors four putative piwi orthologs. We show that Rp-piwi2, Rp-piwi3 and Rp-ago3, but not Rp-piwi1 transcripts are produced in the germline tissues and maternally deposited in the mature eggs. Consistent with a role in Rhodnius oogenesis, parental RNAi against the Rp-piwi2, Rp-piwi3 and Rp-ago3 results in severe egg laying and female adult fertility defects. Furthermore, we show that the reduction of the Rp-piwi2 levels by parental RNAi disrupts oogenesis by causing a dramatic loss of trophocytes, egg chamber degeneration and oogenesis arrest. Intriguingly, the putative Rp-Piwi2 protein features a polyglutamine tract at its N-terminal region, which is conserved in PIWI proteins encoded in the genome of other Triatomine species. Together with R. prolixus, these hematophagous insects are primary vectors of the Chagas disease. Thus, our data shed more light on the evolution of the piRNA pathway and provide a framework for the development of new control strategies for Chagas disease insect vectors.

    Palavras-Chave: trypanosoma; protozoa; insects; proteins; rna processing; drosophila; disease vectors

  • IPEN-DOC 25259

    FAUSTINO, M.G. ; LANGE, C.N. ; MONTEIRO, L.R. ; FURUSAWA, H.A. ; MARQUES, J.R. ; STELLATO, T.B. ; SOARES, S.M.V. ; SILVA, T.B.S.C. da ; SILVA, D.B. da ; COTRIM, M.E.B. ; PIRES, M.A.F. . Top down arsenic uncertainty measurement in water and sediments from Guarapiranga dam (Brazil). Journal of Physics: Conference Series, v. 975, p. 1-6, 2018. DOI: 10.1088/1742-6596/975/1/012024

    Abstract: Total arsenic measurements assessment regarding legal threshold demands more than average and standard deviation approach. In this way, analytical measurement uncertainty evaluation was conducted in order to comply with legal requirements and to allow the balance of arsenic in both water and sediment compartments. A top-down approach for measurement uncertainties was applied to evaluate arsenic concentrations in water and sediments from Guarapiranga dam (São Paulo, Brazil). Laboratory quality control and arsenic interlaboratory tests data were used in this approach to estimate the uncertainties associated with the methodology.

    Palavras-Chave: arsenic; water pollution monitors; sediments; dams; water reservoirs; sediment-water interfaces; quality control

  • 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

  • IPEN-DOC 24675

    ALMEIDA, S.B. ; VILLANI, D. ; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L. . TL and OSL dosimetric characterization of different luminescent materials for clinical electron beams application in TSEB treatments. Journal of Luminescence, v. 198, p. 497-501, 2018. DOI: 10.1016/j.jlumin.2018.02.065

    Abstract: Thermoluminescent dosimeters (TLDs) play an important role in radiotherapy for the dosimetry of ionizing radiation. This type of dosimeter presents advantages that makes them a useful tool for measurements in anthropomorphic phantoms and in vivo dosimetry. Several dosimetric materials have been used in the radiotherapy sectors such as LiF, μLiF, CaSO4:Dy. The OSL dosimetry has also been widely applied using Aluminum Oxide (Al2O3:C). These dosimeters have advantages over TLDs due to their high sensitivity, extensive linearity in response to the dose, faster reading, possibility of multiple readings and the need to perform the heat treatment of the samples. The aim of this work was to compare and characterize, using TL and OSL techniques, different luminescent dosimeters (LiF, μLiF, CaSO4:Dy and Al2O3:C) to be applied in clinical electron beam used to TSEB treatments. Measurements were performed in order to study the applicability of these detectors as easy-to-take alternatives to calibration and measurements of TSEB treatments. Parameters such as dose-response curves; average sensitivity to radiation, intrinsic efficiency and energy and angular dependences were evaluated. The results show good agreement within CaSO4:Dy and TLD-100 measurements and, applying energy and angle dependence factors over the other two materials, all the four detectors can be applied as alternative easy-to-take dosimetric tools for commissioning and quality assurance of 6 MeV clinical electron beams used in TSEB treatments.

    Palavras-Chave: thermoluminescent dosimetry; radiotherapy; aluminium oxides; electron beams; electron dosimetry; ionizing radiations; luminescence; dosimetry; thermoluminescent dosemeters; performance; quality assurance; thermoluminescence

  • IPEN-DOC 24732

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

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

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

  • IPEN-DOC 24728

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

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

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

  • IPEN-DOC 24797

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

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

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

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Autor: Maprelian

Título: loss of coolant

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Ano de publicação: 2015

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

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

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