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  • IPEN-DOC 28771

    VALLINOTO, PRISCILA ; MOREIRA, EDSON G. ; MAIHARA, VERA A. . Estimation of daily dietary intake of essential minerals and trace elements in commercial complementary foods marketed in Brazil. Food Chemistry Advances, v. 1, p. 1-7, 2022. DOI: 10.1016/j.focha.2022.100039

    Abstract: Eating habits influence health and development throughout life and commercial complementary foods are an important part of the diet for many infants. In this study, Ca, Fe, K, Mn, Mg, Na, Se and Zn were determined in twenty-seven Brazilian commercial complementary foods samples by Instrumental Neutron Activation Analysis. Daily dietary intakes of the elements were estimated in three groups aged 6–8 months, 9–11 months and 12–24 months from breastfed and non-breastfed infants and young children. Non-breastfed children presented higher daily dietary intakes for all elements. Daily dietary intakes of Fe, Mg, Mn, Na and Zn did not meet the recommended values for the 6–8 and 9–11 months for the breastfeeding group. Ca, K, Mg, Mn, Na and Zn dietary intakes were below the recommended values for 12–24 months for breastfeeding group. Se daily dietary intakes were inadequate in all studied groups. No investigated element exceeded the upper limits. It was observed that the commercial infant food analyzed do not provide sufficient amount of essential minerals and trace elements for the child healthy development in accordance to the international health recommendations.

    Palavras-Chave: nutrition; diet; intake; minerals; nutrients; neutron activation analysis; children; pediatrics; food industry; insurance

  • IPEN-DOC 28770

    ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; KLUMPP, RAFAEL E. ; AYUSSO, VICTOR H. ; DONATUS, UYIME ; COSTA, ISOLDA . TSA anodising voltage effects on the near-surface coarse intermetallic particles in the AA2024-T3 and AA2198-T8 alloys. Corrosion Engineering, Science and Technology, v. 57, n. 4, p. 380-396, 2022. DOI: 10.1080/1478422X.2022.2071666

    Abstract: In this study, the behaviour of the micrometric particles of the AA2198-T8 alloy during anodising at various voltages and the effect of anodising voltage on the anodised surface morphology have been investigated in a tartaric-sulfuric acid anodising solution. The results were compared with that of the AA2024-T3 alloy. For the AA2198-T8 alloy, partial dissolution of these particles occurred at 0, 3 and 4 V. Besides, for potentials above 5 V, there is a preferential dissolution of the intermetallic particles. For the AA2024-T3 alloy, the results indicated a total dissolution of the micrometric particles at 0 V and a partial dissolution at 3 V, whereas above 4 V total dissolution occurred. Between 1 and 2 V, no dissolution was observed for both alloys. The preferential dissolution of the micrometric particles resulted in defects in the anodic film and cavities on the anodised surfaces.

    Palavras-Chave: aluminium alloys; intermetallic compounds; particle size; anodization; sulfuric acid; tartaric acid

  • IPEN-DOC 28769

    TEIXEIRA, LUIZ F.S. ; GIGLIOTTI, RODRIGO; FERREIRA, LUANA da S.; BELLINI, MARIA H. . Identification of appropriate housekeeping genes for gene expression studies in human renal cell carcinoma under hypoxic conditions. Molecular Biology Reports, v. 49, p. 3885-3891, 2022. DOI: 10.1007/s11033-022-07236-0

    Abstract: Background: Hypoxia pathways are deregulated in clear renal cell carcinoma (ccRCC) because of the loss of the von Hippel-Lindau tumor suppressor function. Quantitative PCR is a powerful tool for quantifying differential expression between normal and cancer cells. Reliable gene expression analysis requires the use of genes encoding housekeeping genes. Therefore, in this study, eight reference candidate genes were evaluated to determine their stability in 786-0 cells under normoxic and hypoxic conditions. Methods and Results: Four different tools were used to rank the most stable genes—geNorm, NormFinder, BestKeeper, and Comparative Ct (ΔCt), and a general ranking was performed using RankAggreg. According to the four algorithms, the TFRC reference gene was identified as the most stable. There was no agreement among the results from the algorithms for the 2nd and 3rd positions. A general classification was then established using the RankAggreg tool. Finally, the three most suitable reference genes for use in 786-0 cells under normoxic and hypoxic conditions were TFRC, RPLP0, and SDHA. Conclusions: To the best of our knowledge, this is the first study to identify reliable genes that can be used for gene expression analysis in ccRCC in a hypoxic environment.

    Palavras-Chave: kidneys; neoplasms; carcinomas; anoxia; genes; standardization

  • IPEN-DOC 28764

    SOUZA, ALANA G. de; KOMATSU, LUIZ G.H. ; BARBOSA, RENNAN F.S.; PARRA, DUCLERC F. ; ROSA, DERVAL S.. The effect of ZnO nanoparticles as Ag‑carrier in PBAT for antimicrobial films. Polymer Bulletin, v. 79, n. 6, p. 4031-4048, 2022. DOI: 10.1007/s00289-021-03681-2

    Abstract: Zinc oxide (ZnO) and ZnO-silver (ZnO-Ag) nanoparticles (NPs) are widely used in different fields, such as biomedicine and food packaging, due to their recognized antibacterial activity and safety for human health. In this paper, ZnO and ZnO-Ag NPs were incorporated into poly(butylene adipate-co-terephthalate) (PBAT), in two contents (0.5 and 1 wt%), to prepare antibacterial films. The NPs were characterized by TEM and FT-Raman, and the films were analyzed by FT-Raman and FTIR, mechanical properties, SEM–EDS, TGA, DSC, XRD, and antibacterial properties against Escherichia coli. The results indicate that both NPs were physically retained in the polymer structure, with a strong electrostatic interaction between the mixture components, reflecting excellent mechanical behavior. The films showed good thermal stability, without significant changes, and the nanocomposites enhanced PBAT crystallinity from 18 to 23% and 27% for PBAT-ZnO and PBAT-ZnO-Ag films, respectively. The mechanical, thermal, and crystallinity results indicated the excellent potential of NPs in biodegradable films to improve properties and expand applicability. The antimicrobial activity is higher for PBAT-ZnO-Ag films than the pristine PBAT due to the synergic effect between the NPs and the oxidation–reduction potential of each nanoparticle, where the ZnO protect and stabilized the Ag-NPs, acting as an Ag-carrier, enhancing its antimicrobial effects after the film’s preparation and allowing its applicability in biomedical products or food packaging.

    Palavras-Chave: antimicrobial agents; zinc oxides; nanoparticles; silver; polymers; bacteria; escherichia coli

  • IPEN-DOC 28697

    LISBOA, CARINA C. ; OLIVEIRA JUNIOR, OLIVIO P. de ; ANDRADE, DELVONEI A. de . Análises de amostras ambientais para fins de salvaguardas nucleares no Brasil / Analysis of environmental samples for nuclear safeguards purposes in Brazil. Quimica Nova, v. 45, n. 3, p. 355-361, 2022. DOI: 10.21577/0100-4042.20170839

    Abstract: The International Atomic Energy Agency (IAEA) is responsible for preventing the proliferation of nuclear weapons by detecting early the misuse of nuclear material or technology, and by certifying that States are honouring their safeguards obligations. The analysis of environmental samples taken by IAEA inspectors during inspections is a powerful tool for nuclear safeguards. This tool was implemented in 1996, after a successful application in Iraq, when a clandestine nuclear weapons program was discovered. The science involved in this type of analysis depends on highly sensitive and selective analytical measurements for detecting traces of nuclear materials collected in the nuclear facility’s “environment”. The purposes of this article are to draw attention to the relevance of this subject in order to address a significant global problem and to present what have been developed in Brazil. Through compatible results with certified standards and IAEA requirements, Brazil has already demonstrated the potential of measuring the amount and isotopic composition of uranium and plutonium at the levels expected in typical environmental samples. Finally, this work suggests the necessary measurements to implement a reliable and consistent environmental samples program for nuclear safeguards in Brazil.

    Palavras-Chave: environment; environmental materials; sample preparation; nuclear materials possession; safeguard regulations; uranium; plutonium; international cooperation

  • IPEN-DOC 28696

    VIVEIROS, BARBARA V.G. de ; DONATUS, UYIME ; ALENCAR, MAICON C. de ; BERBEL, LARISSA O. ; COSTA, ISOLDA . Comparing the corrosion behaviour of AA2050 and AA7050 aluminium alloys by scanning vibrating electrode and scanning ion-selective electrode techniques. Corrosion Engineering, Science and Technology, v. 57, n. 1, p. 85-96, 2022. DOI: 10.1080/1478422X.2021.1992132

    Abstract: The susceptibility to localised corrosion of the high strength alloys, AA2050-T84 and AA7050-T7451, used in the aerospace industry, was investigated in this study by localised electrochemical techniques, specifically, scanning vibrating electrode technique (SVET) and scanning ion-selective electrode technique (SIET), in 0.005 mol L−1 NaCl solution. The study was initially carried out using both alloys individually and then, coupling the two alloys and evaluating the effect of galvanic coupling between them. The results revealed that the AA2050-T84, being nobler than the AA7050-T7451, presented higher corrosion current density values when tested in isolation and the depth of corrosion penetration was significantly deeper in the AA2050-T84 alloy than in the AA7050-T7451. However, galvanic coupling of the two alloys resulted in cathodic protection of the AA2050-T84 alloy and a reduction in corrosion current densities on both alloys.

    Palavras-Chave: aluminium alloys; corrosion resistance; intergranular corrosion; pitting corrosion; coupling; electrochemical corrosion; electrodes; ion-selective electrodes

  • IPEN-DOC 28694

    CORREA, NICOLI D.G. ; SILVA, FELIPE D. ; VIEIRA, DANIEL P. ; SOARES, CARLOS R.J. ; QUEIROZ, ALVARO A.A. de . In vitro cytotoxic data on Se-methylselenocysteine conjugated to dendritic poly(glycerol) against human squamous carcinoma cells. Journal of Biomaterials Science, Polymer Edition, v. 33, n. 5, p. 651-667, 2022. DOI: 10.1080/09205063.2021.2008788

    Abstract: Polymeric nanoparticles acting as sources of selenium (Se) are currently an interesting topic in cancer chemotherapy. In this study, polyglycerol dendrimer (DPGLy) was functionalized with seleno-methyl-selenocysteine (SeMeCys) by means of Steglich esterification with 4-dimethylaminopyridine/(l-ethyl-3-(3-dimethylaminopropyl)carbodiimide) (EDC/DMAP) and cerium chloride as cocatalyst in acetonitrile at quantitative yields of 98 ± 1%. The SeMeCys coupling DPGLy efficiency vs. time were determined by Fourier Transform infrared spectroscopy (FTIR) and ultraviolet–visible (UV–Vis) spectroscopy. The cytotoxic effects of SeMeCys–DPGLy on the Chinese Hamster ovary cell line (CHO-K1) and head and neck squamous cell carcinoma (HNSCC) cells line were assessed by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. No signs of general toxicity of SeMeCys–DPGLy against CHO-K1 cells were detectable at which cell viability was greater than 98%. MTS assays revealed that SeMeCys–DPGLy reduced HNSCC cell viability and proliferation at higher doses and long incubation times.

    Palavras-Chave: selenium; dendrimers; glycerol; toxicity; carcinomas; bioassay; in vitro

  • IPEN-DOC 28693

    SOUZA, CARLA D. de ; BARBEZAN, ANGELICA B. ; ROSERO, WILMMER A.A. ; SANTOS, SOFIA N. dos ; CARVALHO, DIEGO V. de S. ; ZEITUNI, CARLOS A. ; BERNARDES, EMERSON S. ; VIEIRA, DANIEL P. ; SPENCER, PATRICK J. ; RIBEIRO, MARTHA S. ; ROSTELATO, MARIA E.C.M. . Synthesis, in vitro testing, and biodistribution of surfactant-free radioactive nanoparticles for cancer treatment. Nanomaterials, v. 12, n. 2, p. 1-13, 2022. DOI: 10.3390/nano12020187

    Abstract: New forms of cancer treatment, which are effective, have simple manufacturing processes, and easily transportable, are of the utmost necessity. In this work, a methodology for the synthesis of radioactive Gold-198 nanoparticles without the use of surfactants was described. The nuclear activated Gold-198 foils were transformed into H198AuCl4 by dissolution using aqua regia, following a set of steps in a specially designed leak-tight setup. Gold-198 nanoparticles were synthesized using a citrate reduction stabilized with PEG. In addition, TEM results for the non-radioactive product presented an average size of 11.0 nm. The DLS and results for the radioactive 198AuNPs presented an average size of 8.7 nm. Moreover, the DLS results for the PEG-198AuNPs presented a 32.6 nm average size. Cell line tests showed no cytotoxic effect in any period and the concentrations were evaluated. Furthermore, in vivo testing showed a high biological uptake in the tumor and a cancer growth arrest.

    Palavras-Chave: radioactivity; nanoparticles; brachytherapy; neoplasms; testing; in vivo; in vitro; gold 198; distribution

  • IPEN-DOC 28692

    BARROS, L.F. ; DIAS, M.S. ; KOSKINAS, M.F. . Experimental determination of k0 and Q0 values for 121Sb, 123Sb and 130Ba targets applying covariance analysis. Applied Radiation and Isotopes, v. 184, p. 1-7, 2022. DOI: 10.1016/j.apradiso.2022.110122

    Abstract: This work consists of an experimental determination of k0 and Q0 for 121Sb, 123Sb and 130Ba targets. Covariance analysis has been introduced to supply not only the overall uncertainties in these parameters but also their correlations. The irradiations were performed near the core of the IEA-R1 4.5 MW swimming-pool nuclear research reactor of the Nuclear and Energy Research Institute (IPEN-CNEN/SP), in São Paulo, Brazil. The epithermal neutron flux shape parameter, alpha, at the irradiation position is very close to zero, which favors to obtain Q0 values more accurately. Two irradiations were carried out in sequence, using two sets of samples: the first with bare samples and the second inside a Cd cover. The activity measurements were carried out in a previously calibrated HPGe gamma-ray spectrometer. The measurements were corrected for: saturation, decay time, cascade summing, geometry, self-attenuation, measuring time and mass. Standard sources of 152Eu, 133Ba, 60Co and 137Cs traceable to a 4πβ−γ primary system were used to obtain the HPGe gamma-ray peak efficiency as a function of the energy. The experimental efficiency curve was performed by a fourth-degree polynomial fit, in the energy range of the standard sources, 121–1408 keV, it contains all correlations between points. For energies above 1408 keV, the efficiencies were obtained by the Monte Carlo Method. The covariance matrix methodology was applied to all uncertainties involved. The final values for k0 and Q0 were compared with the literature.

    Palavras-Chave: gamma spectroscopy; monte carlo method; monte carlo method; antimony isotopes; barium 130; reactors; antimony 123; antimony 121

  • IPEN-DOC 28691

    KHAN, ZAHID U.; UCHIYAMA, MAYARA K.; KHAN, LATIF U.; ARAKI, KOITI; GOTO, HIRO; FELINTO, MARIA C.F.C. ; SOUZA, ANA O. de; BRITO, HERMI F. de; GIDLUND, MAGNUS. Wide visible-range activatable fluorescence ZnSe:Eu3+/Mn2+@ZnS quantum dots: local atomic structure order and application as a nanoprobe for bioimaging. Journal of Materials Chemistry B, v. 10, n. 2, p. 247-261, 2022. DOI: 10.1039/d1tb01870a

    Abstract: The development of QDs-based fluorescent bionanoprobe for cellular imaging fundamentally relies upon the precise knowledge of particle–cell interaction, optical properties of QDs inside and outside of the cell, movement of a particle in and out of the cell, and the fate of particle. We reported engineering and physicochemical characterization of water-dispersible Eu3+/Mn2+ co-doped ZnSe@ZnS core/shell QDs and studied their potential as a bionanoprobe for biomedical applications, evaluating their biocompatibility, fluorescence behaviour by CytoViva dual mode fluorescence imaging, time-dependent uptake, endocytosis and exocytosis in RAW 264.7 macrophages. The oxidation state and local atomic structure of the Eu dopant studied by X-ray absorption fine structure (XAFS) analysis manifested that the Eu3+ ions occupied sites in both ZnSe and ZnS lattices for the core/shell QDs. A novel approach was developed to relieve the excitation constraint of wide bandgap ZnSe by co-incorporation of Eu3+/Mn2+ codopants, enabling the QDs to be excited at a wide UV-visible range. The QDs displayed tunable emission colors by a gradual increase in Eu3+ concentration at a fixed amount of Mn2+, systematically enhancing the Mn2+ emission intensity via energy transfer from the Eu3+ to Mn2+ ion. The ZnSe:Eu3+/Mn2+@ZnS QDs presented high cell viability above 85% and induced no cell activation. The detailed analyses of QDs-treated cells by dual mode fluorescence CytoViva microscopy confirmed the systematic color-tunable fluorescence and its intensity enhances as a function of incubation time. The QDs were internalized by the cells predominantly via macropinocytosis and other lipid raft-mediated endocytic pathways, retaining an efficient amount for 24 h. The unique color tunability and consistent high intensity emission make these QDs useful for developing a multiplex fluorescent bionanoprobe, activatable in wide-visible region.

    Palavras-Chave: quantum dots; zinc selenides; europium; manganese; zinc sulfides; biological functions; cell membranes; particle interactions

  • IPEN-DOC 28690

    REIS, T.A.; TRALAMAZZA, S.M.; COELHO, E.; ZORZETE, P.; FAVARO, D.I.T. ; CORREA, B.. Early expression of the aflatoxin gene cluster in Aspergillus nomiae isolated from Brazil nut. Toxicon, v. 209, p. 36-42, 2022. DOI: 10.1016/j.toxicon.2022.01.008

    Abstract: Aspergillus nomiae is the most important contaminant in Brazil nut due to its high incidence in these nuts and its strong production of carcinogenic metabolites: aflatoxins (AF). Aflatoxin biosynthesis pathway in A. nomiae is poorly studied. Thus, in present investigation, aflatoxin production and gene cluster (aflC, aflQ, aflU, and aflX) expression profile were evaluated on two strains of A. nomiae isolated from Brazil nut samples collected in the Amazon region, and cultivated on Brazil nut-based medium. The results showed that the expression of the aflatoxin gene cluster in A. nomiae, started at day 2 and occurred before the production of aflatoxins. Aflatoxin production (AFB1 and AFG1) was detected on day 3 on both strains. From day 4 onwards, all four toxins were detected and their production kept at similar proportions (AFG1>AFB1>AFG2>AFB2). Thus, the anticipated information obtained through early expression profile results of aflC, aflQ, aflU, and aflX gene cluster in A. nomiae may foresee aflatoxin production before its detection in Brazil nuts.

    Palavras-Chave: nuts; genes; aspergillus; aflatoxins; biosynthesis; gene regulation; mycotoxins

  • IPEN-DOC 23958

    QUEIROZ, F.M. ; TOMACHUK, C.R. ; ZUMELZU, E.; MELO, H.G. de; COSTA, I. . Effect of trivalent chromium based treatment on the protective properties of steel coated with polymeric film. ECS Transactions, v. 43, n. 1, 2012. DOI: 10.1149/1.4704937

    Abstract: Three main requirements are mandatory in order to achieve optimal quality in canned food: adequate processing of the product, definition of the preserving method, and a correct alloy for the deposit. Lacquer coatings are applied on food cans to enhance corrosion protection and also with decorative purposes. In this investigation, steel coated with a Cr3+ based treatment layer and polyethylene teraphtalate polymeric film (PET), applied by coextrusion, was characterized by electrochemical impedance spectroscopy (EIS) measurements, in NaCl 0.5 M solution, to evaluate the coating corrosion resistance in this environment. The experimental results showed that this new material (tin free) has good corrosion resistance regardless of the porosity found in the polymeric film, indicating that it can be a non-polluting alternative to replace tinplate and hexavalent chromium conversion layer in the food industry, being compatible with the packed product.

    Palavras-Chave: chromium compounds; polymers; films; polyethylene terephthalate; corrosion resistance

  • IPEN-DOC 28689

    RIBEIRO, LUCAS A.S. ; NEGRINI NETO, O. ; FREITAS, ANDERSON Z. de . Determinação de características mecânicas de folhas de papel utilizando a técnica de tomografia por coerência óptica, e suas aplicações na área forense / Determination of mechanical characteristics of sheets of paper using the optical coherence tomography technique and its applications in forensic sciences. Revista Brasileira de Ensino de Física, v. 44, p. e20210394-1 - e20210394-12, 2022. DOI: 10.1590/1806-9126-RBEF-2021-0394

    Abstract: Apresentamos nesse trabalho, uma metodologia para avaliar a pressão de punho durante o processo de escrita manual. Utilizando a tomografia por coerência óptica, foi possível determinar a deformação sofrida pelo papel durante o processo de escrita manual. Foi realizada uma calibração da deformação sofrida pelo papel em função da pressão exercida pela caneta, tornando possível determinar vários parâmetros de interesse, como por exemplo, o raio da esfera da ponta da caneta R = 488 ± 2μm, o coeficiente de Poisson ν = 0, 30 ± 0, 02 e o módulo de Young efetivo do papel sulfite 75 g/m2. Para tal, desenvolvemos um método de determinação do módulo de Hooke para uma mola, com a qual construímos um dispositivo para aplicação de uma força conhecida a uma caneta esferográfica durante o processo de escrita manual. Realizamos também o estudo em função do tipo de substrato, sendo que cinco voluntários tentaram copiar a mesma assinatura em quatro tipos diferentes de papel. Com o auxílio da técnica de tomografia por coerência óptica demonstramos que é possível diferenciar a autoria de uma assinatura também pela profundidade da deformação no papel. O procedimento experimental tornou possível ainda determinar o coeficiente de Poisson e determinar o Módulo de Young efetivo do papel.

    Palavras-Chave: surface tension; young modulus; hands; pressure range; poisson equation; strain rate

  • IPEN-DOC 28688

    PRADO, FELIPE M. ; UTIYAMA, KAREN A.U.; TOFFOLI, DANIEL J.; WETTER, NIKLAUS U. ; SILVA, SIDNEY L. da. Computational algorithm from the Huygens-Fresnel’s diffraction integral for two-dimensional holographic reconstruction. Revista Brasileira de Ensino de Física, v. 44, p. e20210193-1 - e20210193-4, 2022. DOI: 10.1590/1806-9126-RBEF-2021-0193

    Abstract: While most common holographic methods of digital reconstruction are based on the convolution theory, for the ease in the mathematical approach, here we present an algorithm by a discretization of the Huygens-Fresnel integral from a Taylor series expansion to produce a bidimensional Fourier transform. Compared to the digital convolution method, the algorithm presented here is more concise and generates a reduction in processing time, since the Fourier transform appears only once in the discretization. Another advantage is associated with the production of results in the frequency domain, allowing the optical information to be obtained directly.

    Palavras-Chave: computer codes; fresnel coefficient; holography; fourier transformation; digital systems; images

  • IPEN-DOC 28687

    MIRANDA, JURANDIR T. de; BRINGEL, FABIANA de A. ; VELOSA, ANA P.P.; PROTOCEVICH, VERONICA; FERNEZLIAN, SANDRA de M.; SILVA, PEDRO L.; CAPELOZZI, VERA L.; MATHOR, MONICA B. ; TEODORO, WALCY R.. Sterilized human skin graft with a dose of 25 kGy provides a privileged immune and collagen microenvironment in the adhesion of Nude mice wounds. PLoS One, v. 17, n. 1, p. 1-15, 2022. DOI: 10.1371/journal.pone.0262532

    Abstract: This study aimed to report the effects of different doses of ionizing radiation on inflammatory and repair stage of human skin graft adherence in Nude mice wounds. Animals were divided into transplanted with irradiated human skin grafts (IHSG) at 25 and 50 kGy (IHSG 25 kGy; IHSG 50 kGy) and non-IHSG and euthanized on the 3rd, 7th and 21st days after the surgery, by gross and microscopic changes, immunostaining for human type I collagen (Col I) and mouse Col I and Col III and inflammatory cells. We found an effectiveness of human split-thickness graft adherence in mice transplanted with IHSG 25 kGy, as well decrease in dermo-epidermal necrosis and neutrophils, lower loss of skin thickness, epithelization and neo-vascularization. Day 21 post-transplantation with IHSG 25 kGy was observed a well-preserved human skin in the border of the graft, a prominent granulation tissue in an organization by proliferated fibroblasts, Col III deposition and increased B-cells and macrophages. A complete adherence of human skin graft occurred with IHSG 25 kGy. We suggest that the ionizing radiation at 25 kGy mediates inflammation and the repair stage of human skin graft adherence in murine model, thus emerging as a potential tool in healing cutaneous wounds.

    Palavras-Chave: animal tissues; skin; grafts; ionizing radiations; radiation doses; immune reactions; collagen; wounds; burns

  • IPEN-DOC 28686

    CHURA-CHAMBI, ROSA M. ; PRIETO-DA-SILVA, ALVARO R. de B.; DI LELA, MATHEUS M. ; OLIVEIRA, JOAO E. ; ABREU, PATRICIA E.A.; MEIRELES, LUCIANA R.; ANDRADE JUNIOR, HEITOR F. de; MORGANTI, LIGIA . High level SARS-CoV-2 nucleocapsid refolding using mild condition for inclusion bodies solubilization: application of high pressure at pH 9.0. PLoS One, v. 17, n. 2, p. 1-14, 2022. DOI: 10.1371/journal.pone.0262591

    Abstract: SARS-CoV-2 Nucleocapsid (N) is the most abundant viral protein expressed in host samples and is an important antigen for diagnosis. N is a 45 kDa protein that does not present disulfide bonds. Intending to avoid non-specific binding of SARS-CoV-2 N to antibodies from patients who previously had different coronaviruses, a 35 kDa fragment of N was expressed without a conserved motif in E. coli as inclusion bodies (N122-419-IB). Culture media and IB washing conditions were chosen to obtain N122-419-IB with high yield (370 mg/L bacterial culture) and protein purity (90%). High pressure solubilizes protein aggregates by weakening hydrophobic and ionic interactions and alkaline pH promotes solubilization by electrostatic repulsion. The association of pH 9.0 and 2.4 kbar promoted efficient solubilization of N122-419-IB without loss of native-like tertiary structure that N presents in IB. N122-419 was refolded with a yield of 85% (326 mg/L culture) and 95% purity. The refolding process takes only 2 hours and the protein is ready for use after pH adjustment, avoiding the necessity of dialysis or purification. Antibody binding of COVID-19-positive patients sera to N122-419 was confirmed by Western blotting. ELISA using N122-419 is effective in distinguishing between sera presenting antibodies against SARS-CoV-2 from those who do not. To the best of our knowledge, the proposed condition for IB solubilization is one of the mildest described. It is possible that the refolding process can be extended to a wide range of proteins with high yields and purity, even those that are sensible to very alkaline pH.

    Palavras-Chave: coronaviruses; proteins; antibodies; enzyme immunoassay; pressure range mega pa 10-100

  • IPEN-DOC 28685

    MOSCA, RODRIGO C.; SANTOS, SOFIA N. dos ; NOGUEIRA, GESSE E.C. ; PEREIRA, DAISA L. ; COSTA, FRANCIELLI C. ; PEREIRA, JONATHAS X.; ZEITUNI, CARLOS A. ; ARANY, PRAVEEN R.. The efficacy of photobiomodulation therapy in improving tissue resilience and healing of radiation skin damage. Photonics, v. 9, n. 1, p. 1-13, 2022. DOI: 10.3390/photonics9010010

    Abstract: The increased precision, efficacy, and safety of radiation brachytherapy has tremendously improved its popularity in cancer care. However, an unfortunate side effect of this therapy involves localized skin damage and breakdown that are managed palliatively currently. This study was motivated by prior reports on the efficacy of photobiomodulation (PBM) therapy in improving tissue resilience and wound healing. We evaluated the efficacy of PBM therapy on 36 athymic mice with 125I seed (0.42 mCi) implantation over 60 days. PBM treatments were performed with either red (660 nm) or near-infrared (880 nm, NIR) LEDs irradiance of 40 mW/cm2, continuous wave, fluence of 20 J/cm2 once per week. Animals were evaluated every 7 days with digital imaging, laser Doppler flowmetry, thermal imaging, µPET-CT imaging using 18F-FDG, and histology. We observed that both PBM treatments—red and NIR—demonstrated significantly less incidence and severity and improved healing with skin radionecrosis. Radiation exposed tissues had improved functional parameters such as vascular perfusion, reduced inflammation, and metabolic derangement following PBM therapy. Histological analysis confirmed these observations with minimal damage and resolution in tissues exposed to radiation. To our knowledge, this is the first report on the successful use of PBM therapy for brachytherapy. The results from this study support future mechanistic lab studies and controlled human clinical studies to utilize this innovative therapy in managing side effects from radiation cancer treatments.

    Palavras-Chave: brachytherapy; modulation; radiations; wounds; light emitting diodes; formation damage; inflammation

  • IPEN-DOC 28684

    VIGATO, ARYANE A.; MACHADO, IAN P.; VALLE, MATHEUS del; ANA, PATRICIA A. da; SEPULVEDA, ANDERSON F.; YOKAICHIYA, FABIANO; FRANCO, MARGARETH K.K.D. ; LOIOLA, MESSIAS C.; TOFOLI, GIOVANA R.; CEREDA, CINTIA M.S.; SAIRRE, MIRELA I. de; ARAUJO, DANIELE R. de. Monoketonic curcuminoid-lidocaine co-deliver using thermosensitive organogels: from drug synthesis to epidermis structural studies. Pharmaceutics, v. 14, n. 2, p. 1-20, 2022. DOI: 10.3390/pharmaceutics14020293

    Abstract: Organogels (ORGs) are remarkable matrices due to their versatile chemical composition and straightforward preparation. This study proposes the development of ORGs as dual drug-carrier systems, considering the application of synthetic monoketonic curcuminoid (m-CUR) and lidocaine (LDC) to treat topical inflammatory lesions. The monoketone curcuminoid (m-CUR) was synthesized by using an innovative method via a NbCl5–acid catalysis. ORGs were prepared by associating an aqueous phase composed of Pluronic F127 and LDC hydrochloride with an organic phase comprising isopropyl myristate (IPM), soy lecithin (LEC), and the synthesized m-CUR. Physicochemical characterization was performed to evaluate the influence of the organic phase on the ORGs supramolecular organization, permeation profiles, cytotoxicity, and epidermis structural characteristics. The physico-chemical properties of the ORGs were shown to be strongly dependent on the oil phase constitution. Results revealed that the incorporation of LEC and m-CUR shifted the sol-gel transition temperature, and that the addition of LDC enhanced the rheological G′/G″ ratio to higher values compared to original ORGs. Consequently, highly structured gels lead to gradual and controlled LDC permeation profiles from the ORG formulations. Porcine ear skin epidermis was treated with ORGs and evaluated by infrared spectroscopy (FTIR), where the stratum corneum lipids were shown to transition from a hexagonal to a liquid crystal phase. Quantitative optical coherence tomography (OCT) analysis revealed that LEC and m-CUR additives modify skin structuring. Data from this study pointed ORGs as promising formulations for skin-delivery.

    Palavras-Chave: curcumin; gels; ketones; anesthetics; skin; inflammation

  • IPEN-DOC 28683

    VIEIRA, TARCIO de A. ; PRADO, FELIPE M. ; WETTER, NIKLAUS U. . Nd:YLF laser at 1053 nm diode side pumped at 863 nm with a near quantum-defect slope efficiency. Optics and Laser Technology, v. 149, p. 1-5, 2022. DOI: 10.1016/j.optlastec.2021.107818

    Abstract: Laser emission at the 1053 nm transition of Nd:YLF4 is demonstrated using diode-side-pumping at 863 nm directly into the emitting level. The laser configuration uses one total internal reflection at the pump face and provides the highest slope efficiency reported for the Nd:YLF4 medium, close to the quantum limit. In quasi-continuous mode, the laser operates with diffraction-limited beam quality and 78.2% slope efficiency with 14.4 W of output power. In continuous mode, 75.7% slope efficiency in both single-mode and multimode operation is achieved, with 13.5 W output power.

    Palavras-Chave: lasers; neodymium lasers; lithium fluorides; yttrium fluorides; crystal doping; optical pumping

  • IPEN-DOC 28682

    SILVA, FLAVIA R.O. ; LIMA, NELSON B. ; BELLINI, MARIA H. ; TEIXEIRA, LUIZ F.S. ; DU, ERIC Y.; JAMSHIDI, NILOUFAR; GOODING, JUSTIN; MARTIN, ADAM D.; MACMILLAN, ALEXANDER; MARQUIS, CHRISTOPHER P.; THORDARSON, PALL. Lanthanide-based β-tricalcium phosphate upconversion nanoparticles as an effective theranostic nonviral vectors for image-guided gene therapy. Nanotheranostics, v. 6, n. 3, p. 306-321, 2022. DOI: 10.7150/ntno.68789

    Abstract: Lanthanide-based beta-tricalcium phosphate (β-TCP) upconversion nanoparticles are exploited as a non-viral vector for imaging guided-gene therapy by virtue of their unique optical properties and multi-modality imaging ability, high transfection efficiency, high biocompatibility, dispersibility, simplicity of synthesis and surface modification. Ytterbium and thulium-doped β-TCP nanoparticles (βTCPYbTm) are synthesized via co-precipitation method, coated with polyethylenimine (PEI) and functionalized with a nuclear-targeting peptide (TAT). Further, in vitro studies revealed that the nanotheranostic carriers are able to transfect cells with the plasmid eGFP at a high efficiency, with approximately 60% of total cells producing the fluorescent green protein. The optimized protocol developed comprises the most efficient βTCPYbTm/PEI configuration, the amount and the order of assembly of βTCPYbTm:PEI, TAT, plasmid DNA and the culturing conditions. With having excellent dispersibility and high chemical affinity toward nucleic acid, calcium ions released from βTCPYbTm:PEI nanoparticles can participate in delivering nucleic acids and other therapeutic molecules, overcoming the nuclear barriers and improving the transfection efficacy. Equally important, the feasibility of the upconversion multifunctional nanovector to serve as an effective contrast agent for imaging modality, capable of converting low-energy light to higher-energy photons via a multi-photons mechanism, endowing greater unique luminescent properties, was successfully demonstrated.

    Palavras-Chave: gene therapy; polyethylenes; nanoparticles; calcium phosphates

  • IPEN-DOC 28681

    DAS, AVISHEK; RAPOSO, GISELE C.C.; LOPES, DANIELA S.; SILVA, EVAIR J. da; CARNEIRO, VANDA S.M.; MOTA, CLAUDIA C.B. de O.; AMARAL, MARCELLO M.; ZEZELL, DENISE M. ; BARBOSA-SILVA, RENATO; GOMES, ANDERSON S.L.. Exploiting nanomaterials for optical coherence tomography and photoacoustic imaging in nanodentistry. Nanomaterials, v. 12, n. 3, p. 1-22, 2022. DOI: 10.3390/nano12030506

    Abstract: There is already a societal awareness of the growing impact of nanoscience and nanotechnology, with nanomaterials (with at least one dimension less than 100 nm) now incorporated in items as diverse as mobile phones, clothes or dentifrices. In the healthcare area, nanoparticles of biocompatible materials have already been used for cancer treatment or bioimaging enhancement. Nanotechnology in dentistry, or nanodentistry, has already found some developments in dental nanomaterials for caries management, restorative dentistry and orthodontic adhesives. In this review, we present state-of-the-art scientific development in nanodentistry with an emphasis on two imaging techniques exploiting nanomaterials: optical coherence tomography (OCT) and photoacoustic imaging (PAI). Examples will be given using OCT with nanomaterials to enhance the acquired imaging, acting as optical clearing agents for OCT. A novel application of gold nanoparticles and nanorods for imaging enhancement of incipient occlusal caries using OCT will be described. Additionally, we will highlight how the OCT technique can be properly managed to provide imaging with spatial resolution down to 10′s–100′s nm resolution. For PAI, we will describe how new nanoparticles, namely TiN, prepared by femtosecond laser ablation, can be used in nanodentistry and will show photoacoustic microscopy and tomography images for such exogenous agents.

    Palavras-Chave: nanomaterials; dentistry; biological materials; photoacoustic effect; optics; optics; optics; tomography

  • IPEN-DOC 28680

    REMOR, MARCELO B.; BOAS, MARCIO A.V.; SAMPAIO, SILVIO C.; DAMATTO, SANDRA R. ; STEVAUX, JOSE C.; REIS, RALPHO R. dos. Sedimentation rate and accumulation of nutrients in the Upper Paraná river floodplain. Journal of Radioanalytical and Nuclear Chemistry, v. 331, p. 1019-1027, 2022. DOI: 10.1007/s10967-021-08153-5

    Abstract: The objective was to rebuild the history of sedimentation and accumulation of nutrients rate in the Upper Paraná River floodplain. Two corers were collected and sliced at intervals of 2 cm. In the sub-samples geochronological analysis was performed by means of the isotope 210Pb, and also the quantification of organic carbon, nitrogen and phosphorus. Garças Pond presented sedimentation rate of 7.7 mm yr(−1) and Patos Pond 6.8 mm yr(−1). The flood pulse is the main regulating factor of the sedimentation rate on the Upper Paraná River floodplain. The total organic carbon derives from allochthonous origin and the limiting productivity nutrient in the system is nitrogen.

    Palavras-Chave: eutrophication; lead 210; nitrogen; nutrients; organic matter; phosphorus; sedimentation

  • IPEN-DOC 28679

    LINHARES, VANESSA do N. ; ARAUJO, LEANDRO G. de ; VICENTE, ROBERTO ; MARUMO, JULIO T. . Enhanced removal of radium from radioactive oil sludge using microwave irradiation and non-ionic surfactant. Journal of Petroleum Science and Engineering, v. 211, p. 1-10, 2022. DOI: 10.1016/j.petrol.2022.110168

    Abstract: Surfactant-based technologies have been studied for the treatment of radioactive waste containing isotopes of radium. Nevertheless, the use of combined processes to remove radium from radioactive oil sludge is scarce in the literature. The objective of this work was to investigate the potential of a non-ionic surfactant to remove radium from raw oil sludge (ROS) and pre-treated, microwave-irradiated oil sludge (POS). Characterization of ROS and POS was made using the following methods: Thermal Gravimetric Analysis, X-ray diffraction, Scanning Electron Microscopy coupled with Energy-Dispersive X-ray Spectroscopy, and gamma spectrometry. The effects of surfactant concentration (0.5–7.5%), temperature (25-60 °C), and contact time (30 and 60 min) were investigated. For ROS, little or no influence on the decontamination process was found for variations in the selected process parameters. For POS, the lowest surfactant concentration (2.5%) was the most efficient, removing about 94% of 226Ra and 228Ra. Neither contact time nor temperature affected removal. For ROS, removal percentages were 50–60% for 226Ra and 35–45% for 228Ra. The results indicated that the surfactant acted more efficiently in the decontamination of POS.

    Palavras-Chave: oils; sludges; radioactive wastes; surfactants; radioisotopes; microwave radiation

  • IPEN-DOC 28678

    CARVALHO, SABRINA G.M. ; MUCCILLO, ELIANA N.S. ; FONSECA, FABIO C. ; MULLER, MICHAEL; SCHULZE-KUPPERS, FALK; BAUMANN, STEFAN; MEULENBERG, WILHELM A.; GUILLON, OLIVIER; MUCCILLO, REGINALDO . Tape-casting and freeze-drying gadolinia-doped ceria composite membranes for carbon dioxide permeation. Journal of Membrane Science, v. 648, p. 1-10, 2022. DOI: 10.1016/j.memsci.2022.120355

    Abstract: Porous ceria: 20 mol% gadolinia (20GDC) ceramic membranes were prepared by tape casting (TC) and freeze-drying (FD) techniques, obtaining ceramic matrices with randomly dispersed round pores and with an aligned pore structure, respectively. Samples were sintered at 1450 °C, followed by infiltration of molten eutectic sodium-lithium carbonates (NLC). The pore morphology of 20GDC-TC and 20GDC-FD composite membranes was evaluated by analysis of scanning electron microscopy images. The electrical resistivity was determined by electrochemical impedance spectroscopy in the 1 Hz - 10 MHz frequency range from 300 °C to 700 °C, covering the solid-to-molten NLC temperature range, showing that the aligned pore structure improved the conductivity of the ceramic matrix in addition to facilitating molten carbonate infiltration, improving the total (bulk + interfaces) electrical conductivity of the composite membrane. Permeation experiments showed high CO2 permeation rates reached 5.35 × 10−7 mol m−2 s−1 Pa−1 at 800 °C. The infiltration of molten sodium-lithium carbonate in gadolinium-doped ceria prepared by the freeze-drying technique is proposed as an optimized procedure for producing membranes for carbon dioxide separation.

    Palavras-Chave: cerium; doped materials; gadolinium oxides; molten salts; carbon dioxide; composite materials

  • IPEN-DOC 22867

    ASSIS, SERGIO L. de ; COSTA, ISOLDA . The effect of polarisation on the electrochemical behavior of Ti-13Nb-13Zr alloy. Materials Research, v. 10, n. 3, p. 293-296, 2007. DOI: 10.1590/s1516-14392007000300014

    Abstract: The effect of potentiostatic polarisation on the electrochemical behavior of the Ti-13Nb-13Zr alloy was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation curves in Hanks’ solution at 37 °C. Potentiodynamic polarisation curves show a passive behavior with a slight current increase as potentials around 1300 mV(SCE). Based on these curves, different potentials were chosen to perform potentiostatic EIS experiments. EIS experimental data were interpreted using different equivalent circuits associated with the duplex nature of the oxide layer. The fitting procedure evidenced the thickening of a defective oxide layer with the applied potentials, corresponding to key points in the potentiodynamic polarisation curves.

    Palavras-Chave: electrochemistry; titanium alloys; niobium alloys; zirconium alloys; biological materials

  • IPEN-DOC 28677

    JEONG, DAUN; SECO, ROGER; EMMONS, LOUISA; SCHWANTES, REBECCA; LIU, YINGJUN; MCKINNEY, KARENA A.; MARTIN, SCOT T.; KEUTSCH, FRANK N.; GU, DASA; GUENTHER, ALEX B.; VEGA, OSCAR ; TOTA, JULIO; SOUZA, RODRIGO A.F.; SPRINGSTON, STEPHEN R.; WATSON, THOMAS B.; KIM, SAEWUNG. Reconciling observed and predicted tropical rainforest OH concentrations. Journal of Geophysical Research: Atmospheres, v. 127, n. 1, p. 1-18, 2022. DOI: 10.1029/2020JD032901

    Abstract: We present OH observations made in Amazonas, Brazil during the Green Ocean Amazon campaign (GoAmazon2014/5) from February to March of 2014. The average diurnal variation of OH peaked with a midday (10:00–15:00) average of 1.0 × 106 (±0.6 × 106) molecules cm−3. This was substantially lower than previously reported in other tropical forest photochemical environments (2–5 × 106 molecules cm−3) while the simulated OH reactivity was lower. The observational data set was used to constrain a box model to examine how well current photochemical reaction mechanisms can simulate observed OH. We used one near-explicit mechanism (MCM v3.3.1) and four condensed mechanisms (i.e., RACM2, MOZART-T1, CB05, CB6r2) to simulate OH. A total of 14 days of analysis shows that all five chemical mechanisms were able to explain the measured OH within instrumental uncertainty of 40% during the campaign in the Amazonian rainforest environment. Future studies are required using more reliable NOx and VOC measurements to further investigate discrepancies in our understanding of the radical chemistry in the tropical rainforest.

    Palavras-Chave: hydroxyl radicals; photochemistry; forests; tropical regions; amazon river; atmospheres; environment

  • IPEN-DOC 28676

    ROSA, MYCHELLE M.L. ; MAIHARA, VERA A. ; TADDEI, MARIA H.T.; CHEBERLE, LUAN T.V.; AVEGLIANO, ROSEANE P. ; SILVA, PAULO S.C. . The use of total diet study for determination of natural radionuclides in foods of a high background radiation area. Journal of Environmental Radioactivity, v. 242, p. 1-9, 2022. DOI: 10.1016/j.jenvrad.2021.106793

    Abstract: The activity concentrations of 40K, 210Pb, 210Po, 226Ra, 228Ra, 228Th, 230Th, 232Th, 234U, and 238U were determined in 82 food samples, grouped into 20 food groups according to the Brazilian Total Diet, which reflects the dietary habits of a population, for the rural and urban areas of Poços de Caldas city, a High Background Radiation Area. The highest activity concentration found in the food samples was due to 40K being present in all types of food. Among the other radionuclides, high activity concentrations were found for 210Pb in beans and salt, 210Po in fish, 226Ra and 228Ra in nuts and seeds. The main food groups that contributed most to the effective dose, in urban and rural regions, were beans and beverages. The effective doses, due to the ingestion of the analysed food groups, were of 0.44 and 0.60 mSv y−1 and the lifetime cancer risks were 1.6 × 10−3 and 2.3 × 10−3 for the urban and rural Poços de Caldas population, respectively.

    Palavras-Chave: diet; natural radioactivity; food; ingestion; background radiation

  • IPEN-DOC 28675

    SILVA, THALITA F. da; CAVALCANTE, RODRIGO P.; GUELFI, DIEGO R.V.; OLIVEIRA, SILVIO C. de; CASAGRANDE, GLEISON A.; CAIRES, ANDERSON R.L.; OLIVEIRA, FELIPE F. de; GUBIANI, JULIANA R.; CARDOSO, JULIANO C. ; MACHULEK JUNIOR, AMILCAR. Photo-anodes based on B-doped TiO2 for photoelectrocatalytic degradation of propyphenazone: identification of intermediates, and acute toxicity evaluation. Journal of Environmental Chemical Engineering, v. 10, n. 2, p. 1-15, 2022. DOI: 10.1016/j.jece.2022.107212

    Abstract: The photoelectrocatalysis (PEC) using B-doped TiO2 photo-anodes for degradation of the propyphenazone (PPZ) was investigated. For this, four different composites based on TiO2 and TiO2-x%B (x = 1, 3 or 5) were synthesized by sol-gel method and supported on titanium substrate by the dip-coating technique. The morphology, optical and electrochemical properties of photo-anodes were evaluated by SEM, TEM, XPS, TGA, DSC, XRD, FTIR, DRS, and sweep voltammetry, respectively. The influence of pH (3, 6 or 9) and electrical potential intensity (+1 V, +2 V or +3 V) used in PEC were evaluated by kinetic study. To understand the synergistic effect of the composition of the photoelectrochemical system, photolysis (PS), electrocatalysis (EC) and photocatalysis (PC) experiments were realized under comparative conditions. Doping 3% of B into TiO2 promoted a decrease in band gap energy (Ebg = 2.91 eV), thus providing better radiation absorption and greater generation of charge carriers on the surface of the photo-anode. Characterization analyzes indicate the presence of B2O3 coexisting with TiO2. The most promising results were obtained using Ti/TiO2-3%B photo-anode (vs a DSA cathode), applying + 1 V at pH 6, resulting in 91% of PPZ degradation after 60 min of PEC treatment. Toxicity tests using A. salina and L. sativa showed that the effluent generated after 2 h of PEC treatment of 30 mg L-1 of PPZ is non-toxic for the studied species. Up to 13 by-products formed during the PEC and PS treatment were detected and a proposal pathway involving possible routes of PPZ degradation were presented.

    Palavras-Chave: photocatalysis; titanium oxides; sol-gel process; inflammation; drugs; toxicity

  • IPEN-DOC 28673

    CRUZ, R.A.; SANTOS, G.A.; NASCIMENTO, M.S.; TERAM, R.; LUCA, R. de; SANTOS, V.T. dos; SILVA, M.R. da; COUTO, A.A. . Modified Scheil equation for the Cu-Sn system and comparison of hardness and electrical conductivity of Cu-8.5wt%Sn alloy directionally solidified. IOP Conference Series: Materials Science and Engineering, v. 1222, p. 1-6, 2022. DOI: 10.1088/1757-899X/1222/1/012014

    Abstract: The Scheil equation, which estimates the concentration of solute in the solid at the solid/liquid interface, does not account for the curvatures of liquidus and solidus lines. We modified the equation to account for these curvatures and compared some microsegregation indexes obtained by the original and the new equations with data from the literature about the Cu-Sn system. The new one can furnish a better approximation of the range of concentration of solute, but a poorer estimate of the maximum volume fraction of the eutectoid mixture. At last, we compared the hardness and electrical conductivity of an upward solidified alloy of this system with its equivalent commercial one. The as-cast alloy has a lower hardness and a higher conductivity due to its columnar structure.

    Palavras-Chave: alloy systems; copper alloys; tin alloys; electric conductivity; equations

  • IPEN-DOC 28672

    SANTOS, G.A. dos; ALVES, T.L.; TERAM, R.; CRUZ, R.A.; NASCIMENTO, M.S. ; SANTOS, V.T. dos; SILVA, M.R. da; COUTO, A.A. ; MACHADO, I.F.. Effects of directional solidification on hardness and microstructure in Al–3wt.%Cu–1wt.%Li alloy. IOP Conference Series: Materials Science and Engineering, v. 1222, p. 1-5, 2022. DOI: 10.1088/1757-899X/1222/1/012008

    Abstract: Solidification is probably one of most important phase transformations in materials manufacturing. Additionally, a wide range of solidification microstructural features is obtained depending on processing parameters. Mechanical properties of the cast are influenced by the microstructure obtained after solidification. The aim of this work is to investigate how solidification conditions affect solidification and the resulting microstructure of the Al– 3wt.%Cu–1wt.%Li (ternary system) alloy. The alloy was solidified unidirectionally upward through a water-cooled steel plate. Results include secondary dendritic arm spacing (SDAS), hardness and microstructure analysis using optical microscopy. Results showed that SDAS values tended to increase as the distance from the heat-exchange surface increased (P). Conversely, hardness decreases as P increased.

    Palavras-Chave: microstructure; solidification; hardness; ternary alloy systems; dendrites

  • IPEN-DOC 28671

    BIDO, DIOGENES de S.; BARROSO, ANTONIO C. de O. ; COHEN, ERIC D.. Métodos complementares de resolução da interpretação incorreta do efeito da colinearidade nas pesquisas de negócios internacionais / Complementary methods to mitigate the misinterpretation of results due to collinearity in international business research. Internext: Revista Eletronica de Negocios Internacionais, v. 17, n. 1, p. 105-129, 2022. DOI: 10.18568/internext.v17i1.681

    Abstract: Objetivos do estudo: evidenciar lacuna metodológica nos trabalhos empíricos da área de Negócios Internacionais que utilizam modelos estruturais, e prescrever métodos complementares para mitigar o problema da colinearidade. Método: empregou-se uma simulação para evidenciar os efeitos da colinearidade em relação à importância e significância dos preditores, e apresentados métodos voltados ao controle do efeito indesejado da colinearidade. Principais resultados: proposição de métodos complementares que incluem o agrupamento das variáveis latentes que apresentam multicolinearidade em modelos de segunda ordem, e a utilização da medida de importância relativa dos preditores. Contribuições teóricas e metodológicas: a contribuição se dá frente à prescricao de técnicas oferecidas à comunidade acadêmica para a realização de pesquisas empíricas, que foram alcançadas pelo presente estudo. Relevância e originalidade: a partir das lacunas apontadas na produção cientifica recente do campo de conhecimento dos Negócios Internacionais, são elencadas medidas para mitigar a questao da colinearidade. Contribuições sociais e para a gestão: dentre as principais implicações gerenciais e sociais alcançadas por meio dos achados aqui apresentados, promove-se o desenvolvimento de pesquisas empíricas robustas, relevantes e confiáveis.

    Palavras-Chave: management; international relations; business; document types; simulation; structural models

  • IPEN-DOC 28670

    LIMA, MARIANA ; GODOI, CAMILA M. ; SANTOS, MONIQUE C.L. ; NANDENHA, JULIO ; NETO, ALMIR O. ; SOUZA, RODRIGO F.B. de . CO2 reduction on Cu/C used as a cathode in a polymeric electrolyte reactor: fuel cell type. International Journal of Hydrogen Energy, v. 47, n. 6, p. 4010-4017, 2022. DOI: 10.1016/j.ijhydene.2021.11.008

    Abstract: CO2 is one of the leading greenhouse gases, so studies that turn this gas into higher value-added products, that function as simpler and cheaper hydrogen stores, as an alcohols, are extremely important. In this work we using a polymeric Electrolyte Reactor– fuel cell type supplied with H2 on platinum anode and dry CO2 in the cathode with a copper-carbon electrocatalyst. Copper nanoparticles supported on carbon Vulcan XC72 were produced by the sodium borohydride reduction method. The XRD revealed the presence of two different phases, CuO and Cu2O. In addition, the TEM images revealed agglomerates presence. The water, formaldehyde, methanol, methane, formic acid, dimethyl ether, oxalic acid, dimethyl carbonate, and ethylene-glycol were observed by differential mass spectroscopy on line with the reaction and the onset potential for each product and these results were confirmed by infrared spectroscopy – ATR-FTIR setup. This work showed the mapping CO2 reduced compounds for onset potential proposing some contributions to the literature.

    Palavras-Chave: fuel cells; carbon dioxide; reduction; polymerization; electrolytes; copper

  • IPEN-DOC 28666

    BUENO, C.C. ; CAMARGO, F. ; GONCALVES, J.A.C. ; PASCOALINO, K. ; MANGIAROTTI, A.; TUOMINEN, E.; HARKONEN, J.. Performance characterization of dosimeters based on radiation-hard silicon diodes in gamma radiation processing. Frontiers in Sensors, v. 3, p. 1-11, 2022. DOI: 10.3389/fsens.2022.770482

    Abstract: The dosimetric response of silicon diodes produced with distinct engineering technologies, Magnetic Czochralski (MCz), and standard Float Zone (Fz), has been investigated, aiming at their use for online dosimeters in gamma radiation processing applications. The p+-n-n+ junction diodes, 300 µm thick with an active area of 25 mm2, are operated as online radiation dosimeters in the short-circuit current mode. In this case, the key dosimetric quantity is the dose rate, which is correlated with the output current from the diode subjected to radiation. Thus, the dose is obtained offline by the integration of the corresponding current signal. The irradiations are performed with an industrial Gammacell 60Co facility at 2.3–2.44 kGy/h covering doses up to 275 kGy. Under continuous irradiation, both diodes delivered current signals whose intensities decreased with accumulated doses. Mitigation of this decay has been accomplished by pre-irradiating the devices to 700 kGy. Polynomial functions best represent the dose responses for either pristine or preirradiated diodes. The relevant dosimetric parameters as response stability, charge sensitivity, and repeatability of current signals (<5%) reveal the better performance of the MCz diode. It is important to note that the whole dataset fully complies with the international standard protocols for routine dosimeters in radiation processing dosimetry. Regarding radiation damage, which in unbiased diodes manifests primarily in the decay of current sensitivity, the results also showed greater tolerance of the MCz diode. Based on these studies, large availability, and better cost-effectiveness, it is possible to endorse the potential use of MCz devices as online routine dosimeters in radiation processing applications. However, the data reproducibility with the accumulated dose, the dose lifespan, and the effect of the irradiation conditions (e.g., temperature, relative humidity, and dose fractionating) remain to be investigated. Works in this direction are currently in progress.

    Palavras-Chave: silicon diodes; radiations; processing; czochralski method; gamma dosimetry

  • IPEN-DOC 28665

    ANDRADE, MARCIO S. ; ISHIKAWA, OTAVIO H. ; COSTA, ROBSON S. ; SEIXAS, MARCUS V.S. ; RODRIGUES, RITA C.L.B.; MOURA, ESPERIDIANA A.B. . Development of sustainable food packaging material based on biodegradable polymer reinforced with cellulose nanocrystals. Food Packaging and Shelf Life, v. 31, p. 1-10, 2022. DOI: 10.1016/j.fpsl.2021.100807

    Abstract: The increased environmental impact and sustainability issues related to conventional food packaging have gained attention and led to a global concern. The massive consumption of conventional food packaging has increased disposal of non-eco-friendly packaging waste, severely damaging the environment. The replacement by sustainable packaging is an important alternative to reduce the enormous volume of plastic waste. In this work, bionanocomposite films composed of PBAT/PLA blend and cellulose nanocrystals (CNCs) extracted from agro-waste were investigated. Characterization of CNCs confirmed that nanocrystals were obtained. Bionanocomposite films presented better hydrophobic character and thermal stability than the blend film. In addition, the tensile strength, elongation at break, and Young's modulus was around 52%, 29%, and 118%, respectively, higher than blend films. These mechanical values were comparable to values of commercial plastic materials that are extensively used in food packaging. Thus, the prepared bionanocomposite films might be an interesting alternative to produce sustainable food packaging materials.

    Palavras-Chave: cellulose; nanocrystals; food; packaging; nanocomposites; sugar cane; bagasse; agricultural wastes

  • IPEN-DOC 28664

    MUGNAINI, ROGERIO; IGAMI, MERY P.Z. ; KRZYZANOWSKI, ROSALY F.. Acesso aberto e financiamento da pesquisa no Brasil: características e tendências da produção científica / Open access and research funding in Brazil: characteristics and trends in scientific production. Encontros Bibli, v. 27, p. 1-26, 2022. DOI: 10.5007/1518-2924.2022.e78818

    Abstract: Objetivo: este estudo se propõe a analisar a distribuição da produção científica brasileira, considerando seu crescimento e possível relação entre as variáveis indexação, financiamento da pesquisa e modalidades de acesso aberto. Mensura a adesão ao acesso aberto, considerando as bases de indexação, a presença ou ausência de financiamento, e as modalidades e áreas de financiamento de pesquisa pela Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp). Método: o estudo tem caráter exploratório, pautando-se em abordagem cientométrica para análise das variáveis de interesse. Considera a totalidade de artigos originais e de revisão publicados por autores filiados a instituições brasileiras no período de 2009 a 2016. Informações sobre as modalidades de financiamento de artigos resultantes de pesquisa financiada pela Fapesp foram obtidos de sua Biblioteca Virtual (BV Fapesp). Resultado: observou um aumento significativo de artigos em acesso restrito na Web of Science (WoS), além de aumento percentual de artigos sem menção a financiamento. Dentre as modalidades de acesso aberto a via Bronze se destaca no início do período, dando lugar à Dourada; e a SciELO representa quase 50% em acesso aberto, quando não há menção a financiamento, e 20% quando se declara o financiamento. As modalidades de fomento Fapesp revelam relação entre: níveis de bolsa e modalidades de acesso aberto, com maior nível e publicação na WoS, e menor nível na SciELO; auxílios Regular e Biota têm na SciELO maior percentual, enquanto Temáticos, CEPIDs e Jovem Pesquisador na WoS. Finalmente, observou-se que praticamente todas as áreas aumentam o percentual de artigos em acesso restrito no final do período, com destaque para as Humanas. Conclusões: a produção científica brasileira sinaliza que a tendência em direção ao acesso aberto é invertida entre os subperíodos analisados. As iniciativas da Fapesp são percebidas, tendo-se observado tendência favorável à via Dourada, em periódicos Web of Science, enquanto o SciELO reforça tal tendência, tanto na pesquisa financiada pela Fapesp, quanto na produção financiada por outras agências, assim como nas publicações sem menção a financiamento. Diante de tais circunstâncias, os pesquisadores de instituições paulistas credenciados em programas de pós-graduação veem-se obrigados a encontrar um ponto de intersecção, que priorize o fator de impacto, porém muitas vezes tendo que abrir mão do acesso aberto.

    Palavras-Chave: libraries; knowledge management; information dissemination; information systems; information centers; data base management; research programs; financing; indexes

  • IPEN-DOC 28663

    SILVA, REJANE M.P. ; SUFFREDINI, HUGO B.; BASTOS, IVAN N.; SANTOS, LUIS F.; SIMOES, ALDA M.P.. Naphthenic acid corrosion of API 5L X70 steel in aqueous/oil environment using electrochemical surface-resolved and analytical techniques. Electrochimica Acta, v. 407, p. 1-12, 2022. DOI: 10.1016/j.electacta.2022.139900

    Abstract: Naphthenic acid corrosion of steel is studied in crude oil/aqueous phase system at ambient temperature, using a biphasic stagnant liquid without emulsification, by means of electrochemical measurements and surface analysis. The in-situ electrochemical impedance is assigned to the processes occurring at the aqueous phase. Corrosion occurred only in the region of the aqueous phase, as crater-shaped pits that eventually coalesced, generating a nearly uniform attack in the vicinity of the oil phase. The impedance values, normalized to the aqueous region only, reveal corrosion rate increasing with the ratio of crude oil/water. Despite the localized character of the anodic oxidation, the iron naphthenate corrosion products became partitioned between the two phases. Surface-resolved electrochemical techniques in aqueous solution revealed enhanced activity of the regions pre-exposed to oil.

    Palavras-Chave: hydroaromatics; electrochemistry; impedance; corrosion

  • IPEN-DOC 28662

    YAMAGATA, CHIEKO ; LEME, DANIEL R. ; RODRIGUES, VANESSA G. ; ERETIDES, GABRIEL T. ; RODAS, ANDREA C.D.. Three routes for the synthesis of the bioceramic powder of the CaO-MgO-SiO2 system. Ceramics International, v. 48, n. 7, p. 9681-9691, 2022. DOI: 10.1016/j.ceramint.2021.12.169

    Abstract: We report three routes for the synthesis of CaO-MgO-SiO2 (CMS) bioceramic powder using different Si sources and synthesis procedures. The ceramic powders were synthesized from Na2SiO3 waste solution by the sol-gel process combined with co-precipitation (synthesis route I and synthesis route II), and from TEOS (tetraethyl orthosilicate) by conventional sol-gel (synthesis route III). Ceramic powders of the CMS multiphase system were obtained, including diopside, wollastonite, akermanite, monticellite and merwinite, which are suitable for application as biomaterial. These powders were sintered at 1200 °C for 2 h to obtain the CMS ceramics. The ceramics mostly contained diopside and wollastonite crystalline phases. Those ceramics when submitted to cytotoxicity tests revealed to be non-cytotoxic, according to ISO10993-5:2009. The ceramics were tested for in vitro bioactivity while soaked in simulated body fluid (SBF) solution. After 14 days, the presence of hydroxyapatite particles on the surface of ceramics was confirmed by Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) micrographs. The surfaces were completely covered with hydroxyapatite, after 21 days. In summary, CaO-MgO-SiO2 (CMS) ceramic powder derived from three routes of synthesis have potential application in the biomedical area. However, further in-vitro and in-vivo studies are needed.

    Palavras-Chave: synthesis; ceramics; biological materials; sol-gel process; coprecipitation

  • IPEN-DOC 28661

    THYSSEN, VIVIAN V.; VILELA, VANESSA B. ; FLORIO, DANIEL Z. de; FERLAUTO, ANDRE S.; FONSECA, FABIO C. . Direct conversion of methane to C2 hydrocarbons in solid-state membrane reactors at high temperatures. Chemical Reviews, v. 122, n. 3, p. 3966-3995, 2022. DOI: 10.1021/acs.chemrev.1c00447

    Abstract: Direct conversion of methane to C2 compounds by oxidative and nonoxidative coupling reactions has been intensively studied in the past four decades; however, because these reactions have intrinsic severe thermodynamic constraints, they have not become viable industrially. Recently, with the increasing availability of inexpensive “green electrons” coming from renewable sources, electrochemical technologies are gaining momentum for reactions that have been challenging for more conventional catalysis. Using solid-state membranes to control the reacting species and separate products in a single step is a crucial advantage. Devices using ionic or mixed ionic−electronic conductors can be explored for methane coupling reactions with great potential to increase selectivity. Although these technologies are still in the early scaling stages, they offer a sustainable path for the utilization of methane and benefit from the advances in both solid oxide fuel cells and electrolyzers. This review identifies promising developments for solid-state methane conversion reactors by assessing multifunctional layers with microstructural control; combining solid electrolytes (proton and oxygen ion conductors) with active and selective electrodes/catalysts; applying more efficient reactor designs; understanding the reaction/degradation mechanisms; defining standards for performance evaluation; and carrying techno-economic analysis.

    Palavras-Chave: hydrocarbons; solid-state plasma; natural gas; coupling; oxidation; electrochemistry

  • IPEN-DOC 28660

    SOUZA, RODRIGO F.B. de ; FLORIO, DANIEL Z.; ANTOLINI, ERMETE; NETO, ALMIR O. . Partial methane oxidation in fuel cell-type reactors for co-generation of energy and chemicals: a short review. Catalysts, v. 12, n. 2, p. 1-20, 2022. DOI: 10.3390/catal12020217

    Abstract: The conversion of methane into chemicals is of interest to achieve a decarbonized future. Fuel cells are electrochemical devices commonly used to obtain electrical energy but can be utilized either for chemicals’ production or both energy and chemicals cogeneration. In this work, the partial oxidation of methane in fuel cells for electricity generation and valuable chemicals production at the same time is reviewed. For this purpose, we compile different types of methane-fed fuel cells, both low- and high-temperature fuel cells. Despite the fact that few studies have been conducted on this subject, promising results are driving the development of fuel cells that use methane as a fuel source for the cogeneration of power and valuable chemicals.

    Palavras-Chave: fuel cells; methane; cogeneration; oxidation; partial oxidation processes

  • IPEN-DOC 28659

    SAVI, M. ; ANDRADE, M.A.B.; VILLANI, D. ; RODRIGUES JUNIOR, O. ; POTIENS, M.P.A. . Development of FFF filaments for bone and teeth representation in 3D printed radiological objects. Brazilian Journal of Radiation Sciences, v. 10, n. 1, p. 1-20, 2022. DOI: 10.15392/bjrs.v10i1.1739

    Abstract: The use of 3D printing technologies is growing widely, including the possibility of designing phantoms for imaging and dosimetry. High attenuation tissues such as cortical bone, dentin and enamel need to be simulated to accurately produce 3D printed phantoms, especially for Fused Filament Fabrication (FFF) printing technology. A commercially available radiopaque FFF filament had been hard to find. This study aims to report, step-by-step, the development of a radiopaque FFF filament. A combination of radiopaque substances (Barium Sulfate - BaSO4 and Calcium Carbonate - CaCO3) were selected for use as fillers in an Acrylonitrile Butadiene Styrene (ABS) matrix and added in quantities calculated using the National Institute of Standards and Technology (NIST) XCOM tool. The filament was homogenized and characterized by analyzing its density and images obtained using Scanning Electron Microscopy (SEM), Computed Tomography (CT) and micro-CT (μCT) scans. Three filaments were produced with different Hounsfield Units (HU) equivalences: XCT-A (1607HU), XCT-B (1965HU) and XCT-C (2624HU) with respective densities of 1.166(6) g/cm³, 1.211(2) g/cm³ and 1.271(3) g/cm³. With these values, high attenuation tissues, such as bones, dentine and enamel, can now be simulated with FFF 3D printing technology, at a low cost of production.

    Palavras-Chave: 3d printing; attenuation; barium sulfates; density; bone tissues; teeth; calcium carbonates; filaments; phantoms; radiology

  • IPEN-DOC 28658

    OLIVEIRA, M.V.L.; SAVI, M. ; ANDRADE, M.A.B.; VILLANI, D. ; POTIENS, M.P.A. ; BRANCO, H.S.; UBEDA, C.; MDLETSHE, S.. Attenuation properties of common 3D printed FFF plastics for mammographic applications. Brazilian Journal of Radiation Sciences, v. 10, n. 1, p. 1-17, 2022. DOI: 10.15392/bjrs.v10i1.1732

    Abstract: The aim of this study was to evaluate the feasibility of using acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) 3D printing filaments as materials for mammography phantom construction, comparing their attenuation properties at two different set-ups: at a Calibration Laboratory and directly to a mammography unit. The attenuation of 3D printed test phantoms of two types of common 3D printing Fused Filament Fabrication (FFF) filaments (ABS and PLA) were characterized in comparison with polymethylmethacrylate (PMMA). The measurements were carried out with standard IEC 61267 X-rays, using RQR 2-M and RQR 4-M beam qualities at the Instruments Calibration Laboratory, and then applied to a mammography unit, with measurements with 28 kV and 35 kV. Attenuation characteristics evaluated indicate the suitable equivalence of PLA to PMMA for 3D printing breast complex phantoms. The plastic materials used in this study suggest that the FFF technique may be suitable for mammography phantom development.

    Palavras-Chave: 3d printing; acrylonitrile; animal tissues; attenuation; butadiene; filaments; mammary glands; phantoms; pmma; styrene; x radiation

  • IPEN-DOC 28657

    NISTI, M.B. ; CAVALCANTE, F. ; SAUEIA, C.H.R. ; MAZZILLI, B.P. . Reducing the risk for the biota by reusing a NORM residue. Brazilian Journal of Radiation Sciences, v. 10, n. 1, p. 1-18, 2022. DOI: 10.15392/bjrs.v10i1.1715

    Abstract: All biota is exposed to natural radiation, the soil being the major source of radionuclides. Phosphogypsum (PG) is classified as a NORM residue of the phosphate fertilizer industry, often used in agriculture, as a soil conditioner. This residue is stored in stacks by the phosphate industries, potentially posing environmental risks. The aim of this study is to compare the risk for the terrestrial and aquatic biota arising from the storage of PG residue in the environment with that arising from its reuse as soil amendment. For this purpose, typical Brazilian soils amended with PG and PG itself were leached with distilled water. The concentration of natural radionuclides in the soil samples were used to evaluate the risk for terrestrial and aquatic biota, using the ERICA Tool. The results for terrestrial biota exposed to soils amended with phosphogypsum showed a risk reduction of about 85%, when compared to the exposure arising from phosphogypsum stacks. Considering the aquatic biota, the results showed a risk reduction of about 46% when comparing to radionuclide concentrations in leachates from phosphogypsum and from the soils amended with phosphogypsum. A new risk reduction assessment was performed to determine exclusively the contribution of the application of PG to the soil using the soil without PG, the risk reduction for terrestrial biota was of 99% and aquatic biota was a 74% reduction. Finally, it can be concluded that the addition of phosphogypsum in soils reduces the risk quotient related to the exposure of terrestrial and aquatic biota, showing that this is a safe practice.

    Palavras-Chave: aquatic ecosystems; e codes; gypsum; natural radioactivity; phosphates; radiation monitoring; radioecological concentration; residues; risk assessment; soils

  • IPEN-DOC 28656

    CASQUERO-VERA, J.A.; LYAMANI, H.; TITOS, G.; MOREIRA, G. de A. ; BENAVENT-OLTRA, J.A.; CONTE, M.; CONTINI, D.; JARVI, L.; OLMO-REYES, F.J.; ALADOS-ARBOLEDAS, L.. Aerosol number fluxes and concentrations over a southern European urban area. Atmospheric Environment, v. 269, p. 1-10, 2022. DOI: 10.1016/j.atmosenv.2021.118849

    Abstract: Although cities are an important source of aerosol particles, aerosol number flux measurements over urban areas are scarce. These measurements are however important as they can allow us to identify the different sources/sinks of aerosol particles and quantify their emission contributions. Therefore, they can help us to understand the aerosol impacts on human health and climate, and to design effective mitigation strategies through the reduction of urban aerosol emissions. In this work we analyze the aerosol number concentrations and fluxes for particles with diameters larger than 2.5 nm measured by eddy covariance technique at an urban area (Granada city, Spain) from November 2016 to April 2018. This is the first study of particle number flux in an urban area in the Iberian Peninsula and is one of the few current studies that report long-term aerosol number flux measurements. The results suggest that, on average, Granada urban area acted as a net source for atmospheric aerosol particles with median particle number flux of 150 × 106 m−2 s−1. Downward negative fluxes were observed in only 12% of the analyzed data, and most of them were observed during high aerosol load conditions. Both aerosol number fluxes and concentrations were maximum in winter and 50% larger than those measured in summer due to the increased emissions from domestic heating, burning of residual agricultural waste in the agricultural area surrounding the site, as well as to the lower aerosol dilution effects during winter. The analysis of the seasonal diurnal variability of the aerosol number concentration revealed the significant impact of traffic emissions on aerosol population over Granada urban area in all seasons. It also shows the impact of domestic heating and agricultural waste burning emissions in winter as well as the influence of new particle formation processes in summer and spring seasons. Closer analysis by wind sector demonstrated that both aerosol concentrations and fluxes from urban sector (where high density of anthropogenic sources is located) were lower than those from rural sector (which includes agricultural area but also the main highway of the city). This evidences the strong impact of aerosol emissions from traffic circulating on the highway on aerosol population over our measurement site.

    Palavras-Chave: urban areas; aerosols; concentration ratio; atmospheres; particles; eddy currents; data covariances

  • IPEN-DOC 20387

    QUEIROZ, FERNANDA M. ; ELSNER, CECILIA I.; TOMACHUK, CELIA R. ; DI SARLI, ALEJANDRO R.; COSTA, ISOLDA . Avaliação do sistema Zn-Cr III-revestimento orgânico por espectroscopia de impedância eletroquímica / Evaluation of Zn-Cr III-organic coating by electrochemical impedance spectroscopy. Tecnologia em Metalurgia, Materiais e Mineração, v. 10, n. 1, p. 8-15, 2013. DOI: 10.4322/tmm.2013.002

    Abstract: O controle da corrosão de aço eletrogalvanizado empregando soluções à base de sais de Cr VI é amplamente conhecido e estudado. No entanto, pesquisadores vêm buscando alternativas para substituir estes sais já que diretrizes ambientais e industriais exigem que sejam banidos. Os revestimentos de conversão à base de Cr III têm mostrado um desempenho compatível aos baseados em Cr VI. Neste trabalho são utilizadas medidas de espectroscopia de impedância eletroquímica (EIE) em NaCl 0,05 mol/L e em Na2SO4 0,1 mol/L, durante o tempo de imersão, para avaliar a resistência à corrosão de aço eletrogalvanizado revestido com tratamento à base de Cr III e pintado com três diferentes revestimentos orgânicos. Os revestimentos orgânicos sãocaracterizados por sua adesão. Os resultados mostram um comportamento semelhante para os três revestimentos e, apesar de uma segunda constante de tempo ter sido observada nos ajustes de EIE, os valores de R2 indicam uma baixa velocidade de corrosão. O sistema Zn – Cr III – revestimento orgânico é compatível ao sistema Zn – Cr VI – revestimento orgânico, para o período de imersão considerado.

    Palavras-Chave: electrochemical coating; impedance; spectroscopy; chromium compounds; steels; organic compounds; coatings

  • IPEN-DOC 28655

    IBARRA-ESPINOSA, SERGIO; FREITAS, EDMILSON D. de; ANDRADE, MARIA de F.; LANDULFO, EDUARDO . Effects of evaporative emissions control measurements on ozone concentrations in Brazil. Atmosphere, v. 13, n. 1, p. 1-14, 2022. DOI: 10.3390/atmos13010082

    Abstract: In this work, the possible benefits obtained due to the implementation of evaporative emissions control measures, originating from vehicle fueling processes, on ozone concentrations are verified. The measures studied are: (1) control at the moment when the tank trucks supply the fuel to the gas stations (Stage 1); (2) control at the moment when the vehicles are refueled at the gas stations, through a device installed in the pumps (Stage 2); (3) same as the previous control, but through a device installed in the vehicles (ORVR). The effects of these procedures were analyzed using numerical modeling with the VEIN and WRF/Chem models for a base case in 2018 and different emission scenarios, both in 2018 and 2031. The results obtained for 2018 show that the implementation of Stages 1 and 2 would reduce HCNM emissions by 47.96%, with a consequent reduction of 19.9% in the average concentrations of tropospheric ozone. For 2031, the greatest reductions in ozone concentrations were obtained with the scenario without ORVR, and with Stage 1 and Stage 2 (64.65% reduction in HCNM emissions and 31.93% in ozone), followed by the scenario with ORVR and with Stage 1 and Stage 2 (64.39% reduction in HCNM emissions and 32.98% in ozone concentrations).

    Palavras-Chave: ozone; air quality; vehicles; pollutants; emission; air pollution control; carbon monoxide

  • IPEN-DOC 28654

    BOAS, CRISTIAN A.W.V. ; SILVA, JEFFERSON de J. ; DIAS, LUIS A.P. ; FREIRE, MARIA R.B. ; BALIEIRO, LUIZA M. ; SANTOS, CAROLINA S.F. dos ; VIVALDINI, BIANCA F. ; BENEDETTO, RAQUEL ; VIEIRA, DANIEL P. ; PASSOS, PRISCILA de Q.S. ; MARUMO, MARIA H. ; TEIXEIRA, LUIS F.S. ; ARAUJO, ELAINE B. de . In vitro and in vivo response of PSMA-617 radiolabeled with CA and NCA lutetium-177. Applied Radiation and Isotopes, v. 180, p. 1-7, 2022. DOI: 10.1016/j.apradiso.2021.110064

    Abstract: The PSMA-targeted radionuclide therapy has been explored since 2015 with radioisotope lutetium-177, whose β− emission range is adequate for micrometastases treatment. This radioisotope is obtained by two different production routes that directly affect the specific activity of lutetium-177 (non-carrier added and carrier added) and, consequently, the specific activity of radiopharmaceuticals, like 177Lu-PSMA-617. The influence of the specific activity of lutetium-177 on the properties of the radiopharmaceutical PSMA-617 was evaluated through pre-clinical studies. The in vitro study pointed to a lower constant of dissociation with non-carrier added lutetium-177 due to the difference in the specific activity. However, competition and internalization assays resulted in similar results for both lutetium-177. Based on these pre-clinical experiments, the total in vitro tumor cell binding and tumor uptake in vivo were similar, with no influence of the specific activity of the 177Lu-PSMA-617. Regardless the specific activity did not directly affect tumor uptake, the tumor/non-target organs ratios were higher for the radiopharmaceutical labeled with carrier added lutetium-177, which had the lowest specific activity.

    Palavras-Chave: prostate; membranes; antigens; lutetium 177; activity levels; in vivo; in vitro; in vitro; radiopharmaceuticals; neoplasm

  • IPEN-DOC 28649

    OLIVEIRA, JOAO M.; VERNUCIO, SILMARA L.; FREDIANI, LARISSA; ANTUNES, PAULA C.G. ; YORIYAZ, HELIO . O método de Análise de Modos de Falha e de seus Efeitos (FMEA) como ferramenta de decisão para os testes de comissionamento de novos sistemas / The use of Failure Mode and Effects Analysis as a decision tool for novel equipment commissioning tests. Revista Brasileira de Física Médica, v. 15, p. 1-7, 2021. DOI: 10.29384/rbfm.2021.v15.19849001576

    Abstract: Foi proposta a utilização da Análise de Modos de Falha e de suas Consequências (FMEA) como ferramenta de decisão para a escolha e priorização dos testes de comissionamento para novos equipamentos. Um aplicador Vienna para braquiterapia ginecológica intersticial foi utilizado como caso de estudo. Escalas de 1 a 5 foram utilizadas para classificar os riscos segundo a sua ocorrência, severidade e detectabilidade. Foram identificados 12 riscos e como resultado da sua classificação nove testes foram selecionados para o comissionamento. O índice de priorização do risco (RPN) médio mais elevado para o aplicador foi de 21,3 correspondente a 17% do máximo possível (125) e o mais baixo de 1,4. Em relação a sua classificação, 33,3% dos riscos tiveram RPN superior a 10 e 25% foram classificados com valor inferior a 5. Nenhum risco teve severidade superior ou igual a 4. Os três primeiros riscos por ordem de prioridade foram de naturezas diversas, sendo o primeiro e o segundo riscos de parâmetro físico, e o terceiro de software. Os testes finais selecionados após a classificação foram os listados inicialmente com base apenas nos riscos. Entretanto, a classificação dos riscos serviu de base para justificar a sua escolha. O método proposto permitiu a determinação dos testes ideais para o comissionamento do aplicador em questão, bem como a identificação dos testes mais críticos e prioritários.

    Palavras-Chave: brachytherapy; decision making; equipment; failure mode analysis; gynecology; radiation source; implants; risk assessment

  • IPEN-DOC 28648

    FUNGARO, DENISE A. ; SILVA, KATIA C. ; MAHMOUD, ALAA E.D.. Aluminium tertiary industry waste and ashes samples for development of zeolitic material synthesis. Journal of Applied Materials and Technology, v. 2, n. 2, p. 66-73, 2021. DOI: 10.31258/Jamt.2.2.66-73

    Abstract: Wastes generated in large amounts have been recognized as sustainable sources of raw materials for the synthesis of adsorbents. The synthesis of zeolite through wastes recycling of two different ash sources (coal bottom ash and sugarcane waste ash) and industrial aluminum waste was evaluated. The molar ratio of SiO2/Al2O3 for zeolite 4A formation was achieved by the addition of aluminum waste from tertiary industry as aluminum source. Coal bottom ash and sugarcane waste ash were used as a source of both silica and alumina. The synthesized materials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and cation exchange capacity (CEC). The analysis of the properties of the products demonstrates that the by-products can be used to produce zeolite A. The utilization of synthesized zeolites as adsorbent for cadmium removal from aqueous solution was conducted following the concept of implementation of utilization of waste materials as a component of the circular economy in the wastewater sector.

    Palavras-Chave: industrial wastes; aluminium; sugar cane; ashes; zeolites; hazardous materials; waste management

  • IPEN-DOC 20149

    COSTA, SANDRA M.C.; REGINALDO, EMERSON I.; COSTA, ISOLDA . Resistência à corrosão de ligas de ferros fundidos perlítico e bainítico em uma solução sintética de condensado a partir dos gases de combustão / Corrosion resistance of pearlitic and bainitic cast iron in a synthetic solution of condensed gas from combustion. Tecnologia em Metalurgia, Materiais e Mineração, v. 12, n. 1, p. 20-28, 2015. DOI: 10.4322/2176-1523.0740

    Abstract: A corrosão em componentes motores presentes na câmara de combustão é normalmente relacionada à formação de ácidos, como sulfúrico e nítrico, neste ambiente. Estes ácidos são gerados pela condensação dos gases de combustão que acontece geralmente nos sistemas de exaustão dos veículos. No entanto, com o desenvolvimento de novas tecnologias destinadas à redução das emissões, a condensação também está sendo promovida nas câmaras de combustão de veículos. Este fato está associado às altas taxas de recirculação de gases de escape, conhecido como EGR, (termo em inglês para Exhaust Gas Recirculation). Consequentemente, os problemas de corrosão nos componentes de motores estão aumentando, especialmente em camisas de cilindros fabricados em ligas de ferro fundido. Neste estudo, foi investigada a resistência à corrosão de duas ligas de ferro fundido, uma com microestrutura perlítica e outra com microestrutura bainítica, em uma solução que simula a composição do condensado obtido a partir dos gases de combustão. Verificou-se que a microestrutura do ferro fundido é um fator determinante, afetando o comportamento de corrosão. Os resultados mostraram que nenhum dos dois materiais investigados é resistente à corrosão no meio de ensaio, e a pequena diferença observada entre os comportamentos dos dois ferros fundidos, foi associada às suas microstruturas, as quais são dependentes de suas composições químicas. O ferro fundido com microestrutura perlítica apresentou menor formação de produtos de corrosão do que o ferro fundido de microestrutura bainítica. Este resultado foi relacionado à presença da fase steadita, altamente estável e resistente à corrosão, na microestrutura perlítica, a qual ancora os produtos de corrosão formados na superfície. Estes atuam como uma barreira parcial retardando o processo de avanço da corrosão, mais pronunciado no ferro fundido bainítico que não apresenta fase steadita.

    Palavras-Chave: corrosion; cast iron; flue gas; exhaust recirculation systems

  • IPEN-DOC 20147

    BALDO, FERNANDO B.; VILLAVICENCIO, ANNA L.C.H. ; SCHMIDT, FLAVIO L.; RAGA, ADALTON. Gamma radiation as a potential phytosanitary squash treatment for the control of Anastrepha grandis (Macquart) (Diptera: Tephritidae). Annual Research & Review in Biology, v. 36, n. 4, p. 19-31, 2021. DOI: 10.9734/arrb/2021/v36i430360

    Abstract: Fruit flies (Diptera: Tephritidae) are the primary pests of horticultural crops worldwide, causing both direct and indirect damage to the fruit production, including Anastrepha grandis (Macquart, 1846), which exclusively infests Cucurbitaceae fruit. Dose-response tests were used to examine the effects of gamma radiation exposure on 24 – 48 h old eggs and third instar larvae, both in vitro and in Atlas squashes (Cucurbita moschata). The following physicochemical properties of Atlas squashes exposed to gamma radiation were evaluated: titratable total acidity, sugar, pH, external colouration, and texture. It was found that under in vitro conditions, a 20.0 Gy dose of gamma radiation was able to prevent larval eclosion, but a 200 Gy dose was necessary to prevent emergence after the exposure of third instar larvae. In Atlas squashes, 200 and 250 Gy doses of gamma radiation were able to prevent the emergence of A. grandis adults from eggs and larvae, respectively. The radiation doses estimated by Probit 9 to prevent emergence from squashes infested with eggs and third instar larvae were 257.13 Gy and 270.25 Gy respectively. The use of gamma radiation did not significantly affect the physicochemical properties of Atlas squashes, which suggested that gamma radiation may represent a potentially useful technique for the quarantine control of A. grandis in cucurbits.

    Palavras-Chave: fruit flies; insects; diptera; food processing; bioassay; gamma radiation

  • IPEN-DOC 28603

    PERINI, ALINE A. ; SHIRAISHI, GUILHERME F.; FREITAS, ANDERSON Z. . Matching technological bid in smart cities initiatives: a case study of innovation fairs at research institute in Brazil. Journal of Business and Economics, v. 12, n. 6, p. 598-607, 2021. DOI: 10.15341/jbe(2155-7950)/06.12.2021/003

    Abstract: The main objective of this work was to present a general framework of the technology roadmap from a central competence of Nuclear and Energy Research Institute from Brazil. The approach provides a structured to strength the join to market mechanism design to survive in complex environment trends to shape the future. The technological innovation impact measures depend from (1) quality of diversified technology knowledge and (2) quality of diversified country industry knowledge. From this big view picture, the Technology Transfer Office took these two general dimensions of impact into account and divided them into four (4) sub-categories that explain potential benefits and performance results in areas such as: a) Current Projects and Programs, b) Patents, c) Education and Teaching and d) Scientific Publications. The sampling contemplated the big picture of performance related in National Management Information System and a repository proper in response to institutional performance growth and plans, programs and projects associated in Innovation key indicators and policy disclosure. The taxonomy to roadmapping innovation impact measure was centered in terms in two potential fields to shape the future: i) Nuclear Research Reactors and/or ii) Nanotechnology.

    Palavras-Chave: nanotechnology; socio-economic factors; research reactors; appropriate technology

  • IPEN-DOC 28602

    PINTO, ANDREIA A.G.; NAGAI, MIRIAN Y. de O.; COIMBRA, EDNAR N.; MOHAMMAD, SUHAM N.; SILVA, JEFFERSON S.; VON ANCKEN, ADALBERTO; PINTO, SANDRA A.G.; AGUIAR, MICHELLE S.; DUTRA-CORREA, MARISTELA; HORTELLANI, MARCOS A. ; MIRANDA, ADRIANA ; SARKIS, JORGE E. de S. ; SUFFREDINI, IVANA B.; PERES, GIOVANI B.; BERNARDI, MARIA M.; CARTWRIGHT, STEVEN J.; BONAMIN, LEONI V.. Bioresilience to mercury chloride of the brine shrimp Artemia salina after treatment with homeopathic Mercurius corrosivus. Homeopathy, v. 110, n. 4, p. 244-255, 2021. DOI: 10.1055/s-0041-1729562

    Abstract: Introduction: Finding solutions to mitigate the impact of pollution on living systems is a matter of great interest. Homeopathic preparations of toxic substances have been described in the literature as attenuation factors for intoxication. Herein, an experimental study using Artemia salina and mercury chloride was developed as a model to identify aspects related to bioresilience. Aims: The aim of the study was to describe the effects of homeopathic Mercurius corrosivus (MC) on Artemia salina cysts hatching and on mercury bioavailability. Methods: Artemia salina cysts were exposed to 5.0 µg/mL of mercury chloride during the hatching phase. MC potencies (6cH, 30cH, and 200cH) were prepared in sterile purified water and poured into artificial sea water. Different controls were used (non-challenged cysts and challenged cysts treated with water, succussed water, and Ethilicum 1cH). Four series of nine experiments were performed to evaluate the percentage of cyst hatching. Soluble total mercury (THg) levels and precipitated mercury content were also evaluated. Solvatochromic dyes were used to check for eventual physicochemical markers of MC biological activity. Results: Significant delay (p < 0.0001) in cyst hatching was observed only after treatment with MC 30cH, compared with controls. This result was associated with an increase of THg concentration in water (p = 0.0018) and of chlorine/oxygen ratio (p < 0.0001) in suspended micraggregates, suggesting changes in mercury bioavailability. A specific interaction of MC 30cH with the solvatochromic dye ET33 (p = 0.0017) was found. Conclusion: Changes in hatching rate and possible changes in Hg bioavailability are postulated as protective effects of MC 30cH on Artemia salina, by improving its natural bioresilience processes.

    Palavras-Chave: ecology; ecosystems; toxicity; pharmacology; drugs; mercury; artemia

  • IPEN-DOC 28601

    CALDERON-HERNANDEZ, JOSE W.; MACHADO, CARULINE de S.C.; COSTA, ISOLDA ; MELO, HERCILIO G. de. Syringe cell to avoid crevice corrosion on stainless steels during potentiodynamic polarization testing. Corrosion, v. 77, n. 12, p. 1274-1277, 2021. DOI: 10.5006/3925

    Abstract: In this study, an electrochemical syringe droplet cell was developed and used to evaluate the pitting corrosion resistance of Type 304 stainless steel. The cell was also adapted to perform measurements in deaerated environment, by means of continuous N2 injection. The results obtained with the syringe cells, in both conditions (aerated and deaerated), were reproducible and free of crevice corrosion because the cell configuration does not allow obtaining this condition. The proposed cell demonstrates coherency with data acquired using conventional cell arrangements, being a potential alternative to study pitting corrosion of passive metals.

    Palavras-Chave: stainless steels; crevice corrosion; pitting corrosion; injection; shielding

  • IPEN-DOC 28600

    MONTEIRO, P.S.P.; SANTOS, G.A. dos; NAKAMOTO, F.Y.; NASCIMENTO, M.S. ; TERAM, R.; SANTOS, V.T. dos; SILVA, M.R. da; COUTO, A.A. ; MACHADO, I.F.; BRANDI, S.D.. Analysis of the influence of continuous-drive friction welding on the microstructure and mechanical properties of the UNS C64200 bronze-aluminum-silicon alloy. Defect and Diffusion Forum, v. 412, p. 185-195, 2021. DOI: 10.4028/

    Abstract: Friction welding (FRW) is an important commercial solid-state welding process in which coalescence is achieved by frictional heat combined with pressure. The objective of this work is to analyze the microstructure and the mechanical behavior of the copper alloy UNS C64200 – bronze-aluminum- silicon, as well as to raise the ideal welding parameters so that there is adequate weldability after process of continuous-drive friction welding. Regarding the analysis of the microstructure, scanning electron microscopy was used to characterize phases. The mechanical properties were evaluated by means of a hardness test of the center of the welded joint, traversing the entire extent of the thermally affected zone. Results show that the UNS C64200 alloy, when subjected to conventional friction welding, behaves satisfactorily in terms of weldability, without the appearance of cracks or defects arising from the temperature characteristic of this process, as well as good hardness with values above the minimum established in norm and higher than the base material.

    Palavras-Chave: microstructure; hardness; tin alloys; aluminium alloys; silicon alloys; friction welding

  • IPEN-DOC 28599

    GUIMARAES, M.A.; SANTOS, G.A. dos; NASCIMENTO, M.S. ; TERAM, R.; SANTOS, V.T. dos; SILVA, M.R. da; COUTO, A.A. ; MACHADO, I.F.. Study on the wear of cutting-tools used in dry machining of Cu-10wt%Al-5wt%Ni-5wt%Fe alloy. Defect and Diffusion Forum, v. 413, p. 194-200, 2021. DOI: 10.4028/

    Abstract: Aluminium bronze alloys are special copper alloys that have a machinability rate from 20 to 40% compared to free cutting brasses, so the cutting parameters and type of tools suitable for machining of these materials may be very different for other copper alloys. Also, due to the relative high costs of the raw material, the absence of contamination of the chips by cutting fluids improve its intrinsic resales value and encourage the use of machining process without coolant. The aim of this work is to evaluate the tool wear mechanisms in the finishing machining of the Cu-10wt%Al- 5wt%Ni-5wt%Fe aluminium-bronze alloy with carbide and cermet inserts at different cutting speeds under dry machining condition. The turning of material showed lower surface roughness in higher speed conditions and better dimensional stability at lower speeds. It was observed the formation of continuous chips, but of little volume occupied. The scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of tool wear show the adhesion as the main tool wear mechanism, followed by abrasion. At the lower cutting speed, the adhesion wears affected significantly the surface finish, reducing the tool life in comparison to the higher speeds.

    Palavras-Chave: aluminium; bronze; alloys; tools; wear; surface finishing; machining

  • IPEN-DOC 28532

    SOUZA, STEPHAN P.M. de; TOBAR, NATALIA; FRASSON, FERNANDA; PERINI, EFRAIN A. ; SOUZA, CARMINO A. de; DELAMAIN, MARCIA T.; RAMOS, CELSO D.. Head-to-head comparison between 68Ga-PSMA and 18F-FDG-PET/CT in lymphomas: a preliminary analysis. Nuclear Medicine Communications, v. 42, n. 12, p. 1355-1360, 2021. DOI: 10.1097/MNM.0000000000001465

    Abstract: Purpose: Isolated case reports mention the uptake of radiolabeled PSMA in lymphoma. However, it is not clear if the intensity of 68Ga-PSMA expression varies among different histological subtypes or if it correlates with 18F-FDG uptake. This study compared both tracers in patients with diverse lymphoma subtypes. Methods: Ten patients with biopsy-proven-lymphoma underwent 18F-FDG and 68Ga-PSMA-PET/CT (maximum time interval: 6 days). Lymphoma subtypes included Hodgkin’s lymphoma (HL, three patients) and aggressive and indolent non-Hodgkin’s lymphoma (NHL, seven patients). The intensity of PSMA uptake was classified visually as low, intermediate, or high, using blood pool, liver and parotid gland uptake as references. Maximum standardized-uptake value (SUVmax) of each affected site was measured in both sets of images. Results: FDG detected 59/59 involved sites in 10 patients and PSMA 47/59 sites in nine patients. PSMA uptake was generally low, regardless of the intensity of FDG uptake, but it was classified as intermediate in two patients. The median SUVmax varied from 2.0 (2.0–8.2) to 30.9 for FDG and from 1.7 (1.7–1.7) to 4.4 for PSMA, P < 0.0001. The primary lesion of one patient had a marked intralesional mismatch uptake pattern of the tracers, with areas of higher PSMA expression than FDG uptake, and vice-versa. A brain lesion was more easily identified with PSMA than with FDG images. Conclusion: HL and several NHL subtypes may present PSMA uptake. The intensity of PSMA expression is generally lower than that of FDG uptake and seems to present less variation among the different histological subtypes of lymphomas.

    Palavras-Chave: diagnosis; neoplasms; prostate; antigens; gallium 68; lymphomas; hodgkins disease

  • IPEN-DOC 28531

    MACHADO, CARULINE de S.C. ; SILVA, REJANE M.P. da ; ARAUJO, JOAO V. de S. ; MILAGRE, MARIANA X. ; DONATUS, UYIME ; VIVEIROS, BARBARA V.G. de ; KLUMPP, RAFAEL E. ; COSTA, ISOLDA . Influence of chloride ions concentration on the development of severe localised corrosion and its effects on the electrochemical response of the 2198-T8 alloy. Corrosion Engineering, Science and Technology, v. 56, n. 4, p. 341-350, 2021. DOI: 10.1080/1478422X.2020.1862390

    Abstract: The development of severe localised corrosion (SLC) on the 2198-T8 alloy was investigated in solutions of various NaCl concentrations (0.001, 0.005 and 0.01 mol L−1). Immersion tests, optical profilometry, conventional and local electrochemical analyses were performed to evaluate the corrosion behaviour of the alloy. Immersion tests showed that the alloy is susceptible to SLC in all conditions, although the pits sizes were dependent on the solution concentration. The largest anodic areas, corresponding to SLC sites, were observed for the sample immersed in 0.001 mol L−1 NaCl, whereas pits with similar sizes were observed for the samples immersed in solutions with 0.005 and 0.01 mol L−1 of NaCl. Moreover, the maximum depth of attack was observed for the sample immersed in 0.001 mol L−1 NaCl. These results were in agreement with the scanning ionselective electrode technique (SIET) maps which showed stronger acidification on the sample exposed to 0.001 mol L−1 NaCl solution.

    Palavras-Chave: aluminium alloys; lithium alloys; copper alloys; chlorides; ions; corrosion

  • IPEN-DOC 28530

    SILVA, PAULO S.C. da ; CAMPOS, MARCIA P. de ; EL HAJJ, THAMMIRIS M.; REIS, GUILHERME de L. . Radon concentrations in a nuclear reactor center in Brazil. Health Physics, v. 121, n. 2, p. 117-123, 2021. DOI: 10.1097/HP.0000000000001430

    Abstract: Radiation workers are normally exposed to doses resulting from their day-to-day activities. Besides that, background radiation, such as radon, can contribute to the exposure rates. The radionuclide 222Rn is a noble gas belonging to the uranium series, and its indoor concentration in the air depends on the exhalation from surrounding soil and the exhalation from building materials. Radon exhaling from porous building materials containing high uranium concentrations can become a significant exposure factor in areas with limited ventilation. The objective of this study was to evaluate the 222Rn concentrations in the radiochemistry and radiometric laboratories in the nuclear reactor building of the Nuclear Reactor Center (CERPq) located in the Institute of Nuclear and Energy Research (IPEN), São Paulo, Brazil. Measurements were done using a Radon Gas Monitor, model RAD7, equipped with a solid-state alpha detector. A passive method (SSNTD) was also used, consisting of square pieces of C-39 foils (2.5 cm × 2.5 cm) placed within small diffusion chambers. The CR-39 detectors were etched in KOH 30% solution at 80 °C for 5.5 h in a constant-temperature bath. After etching, the detectors were washed, dried, and scanned using a microscope to obtain the track density measurements. The activity concentrations measured with both techniques varied from 52 to 103 Bq m−3 in the studied areas of the CERPq. These values may be compared to the reference level of 100 Bq m−3 established by the World Health Organization to ensure safety environments.

    Palavras-Chave: radon 222; radiation doses; occupational exposure; reactors

  • IPEN-DOC 28529

    SCURO, N.L. ; ANGELO, G. ; ANGELO, E.; UMBEHAUN, P.E. ; TORRES, W.M. ; SANTOS, P.H.G. ; FREIRE, L.O. ; ANDRADE, D.A. . RANS-based CFD calculation for pressure drop and mass flow rate distribution in an MTR fuel assembly. Nuclear Science and Engineering, v. 195, n. 4, p. 349-366, 2021. DOI: 10.1080/00295639.2020.1825306

    Abstract: This work presents a Reynolds-averaged Navier Stokes–based computational fluid dynamics methodology for the calculation of pressure drop and mass flow rate distribution in a material test reactor flat-plate-type standard fuel assembly (SFA) of the IEA-R1 Brazilian research reactor to predict future improvements in newer SFA designs. The results improve the understanding of the origin of fuel plate oxidation due to high temperatures, and consequently, due to the internal flow dynamics. All numerical analyses were performed with the ANSYS-CFX® commercial code. The observed results show that the movement pin decreases the central channel mass flow due to the length of the vortex at the inlet region. However, the outlet nozzle showed greater general influence in the flow dynamics. It should have a more gradual cross-section transition being away from the fuel plates or a squarer-shaped design to get a more homogeneous mass flow distribution. Optimizing both regions could lead to a better cooling condition. The validation of the IEA-R1 numerical methodology was made by comparing the McMaster University’s dummy model experiment with a numerical model that uses the same numerical methodology. The experimental data were obtained with laser Doppler velocimetry, and the comparison showed good agreement for both pressure drop and mass flow rate distribution using the Standard k-ω turbulence model.

    Palavras-Chave: computer calculations; computerized simulation; fluid mechanics; materials testing; reactor materials

  • IPEN-DOC 28528

    FUJIMOTO, T.G. ; STEIL, M.C.; MUCCILLO, E.N.S. . Electrical conductivity of La0.9Sr0.1Ga0.8Mg0.2O3-y-La1.55Sr0.45Ga3O7+δ composite electrolyte. ECS Transactions, v. 103, n. 1, p. 2163-2172, 2021. DOI: 10.1149/10301.2163ecst

    Abstract: Doped lanthanum gallate constitutes a family of solid electrolytes with high ionic conductivity, wide electrolytic domain, and good chemical stability. The combination of its properties turns some compounds of this family promising candidates for application in solid oxide cells operating at intermediate temperatures. In this work, La0.9Sr0.1Ga0.8Mg0.2O3-y - xLa1.55Sr0.45Ga3O7+δ with x = 0, 1, and 5 wt.% were investigated aiming to obtain a composite solid electrolyte with optimized properties compared to the parent material. Composite electrolytes were prepared by solid state reaction method and evaluated for densification, phase content, and microstructure. Electrical conductivity measurements were carried out as a function of temperature and oxygen partial pressure. Increase on densification and structural homogeneity were obtained with increasing fraction of the melilite phase. The electrical conductivity determined by impedance spectroscopy revealed a decrease of the bulk resistivity for increasing amounts of La1.55Sr0.45Ga3O7+δ.

    Palavras-Chave: composite materials; electric conductivity; doped materials; electrolytes

  • IPEN-DOC 28527

    FONSECA, F.C. ; TABUTI, F. ; MORAES, T. ; ABE, R.; GUIMARAES, R.M.; MIURA, Y.; FUKUYAMA, Y.. Exploring the stability of direct ethanol solid oxide fuel cells at intermediate temperature. ECS Transactions, v. 103, n. 1, p. 169-178, 2021. DOI: 10.1149/10301.0169ecst

    Abstract: Anode supported fuel cells were tested in direct (no water added) bioethanol at intermediate temperature (600°C and 700°C). The standard fuel cell has reasonable short-term stability under dry ethanol if current is continuously drawn at a minimum fuel utilization factor at 700ºC. However, the YSZ/Ni anode develops carbon deposits as inferred from post fuel cell test analyses and fixed bed steam reforming catalytic tests at 600°C. Thus, an active catalytic layer with tailored properties for ethanol internal reforming was studied. Initial tests investigated the Ir/gadolinium-doped ceria catalysts previously proven stable at 850°C. The main results have shown that the catalytic layer has no significant effect on the performance of the fuel cell running under hydrogen. The use of a ceria-based catalytic layer has enhanced the stability of the fuel cell under dry ethanol at 700°C, but stable operation at 600°C requires the development of more active catalyst.

    Palavras-Chave: ethanol; solid oxide fuel cells; direct ethanol fuel cells; raman spectra

  • IPEN-DOC 28526

    VILELA, V.B. ; THYSSEN, V.V.; RODRIGUES, L.N. ; FONSECA, F.C. . Enhancing the catalytic activity of lanthanum-ceria fluorite for methane conversion in SOFC. ECS Transactions, v. 103, n. 1, p. 1917-1925, 2021. DOI: 10.1149/10301.1917ecst

    Abstract: A2B2O7 compounds with tailored compositions exhibit catalytic properties in a variety of high-temperature reactions, such as oxidative coupling of methane (OCM). La2Ce2O7 performs well in OCM due to selective mobile oxygen species, and suitable alkaline sites. Doping with Ca2+ increases the alkalinity, which can considerably increase selectivity for C2 products in OCM. We have explored the combustion synthesis to obtain homogeneous Ca2+-doped La2Ce2O7 materials to use as a catalytic layer in SOFC reactors for methane direct conversion to C2. The addition of Ca2+ in the A site of La2Ce2O7 resulted in the disordered fluorite-type crystalline structure. The formation of superficial oxygen vacancies related to the active oxygen species, which may benefit the OCM reaction, was detected. Electrochemical characterization showed no significant dependence of the conductivity with Ca2+-doping.

    Palavras-Chave: lanthanum oxides; cerium oxides; oxygen compounds; solid oxide fuel cells; catalysts

  • IPEN-DOC 28525

    RODRIGUES, L.N. ; MACHADO, MARINA ; MORAES, L.P.R. ; THYSSEN, V.V.; FONSECA, F.C. . Development of anode-supported solid oxide fuel cell by co-tape casting and co-sintering. ECS Transactions, v. 103, n. 1, p. 2245-2251, 2021. DOI: 10.1149/10301.2245ecst

    Abstract: Simple and cost-effective technologies to produce solid oxide fuel cells require control of microstructure, thickness, homogeneity, and reproducibility of the functional layers. The manufacturing of a solid oxide fuel cell (SOFC) involves significant ceramic processing challenges to obtain layers with controlled microstructure. Possibly the most common technique for large-scale production of SOFCs is tape casting. In this study, YSZ electrolyte and 60NiO/YSZ anode slurries were studied for the production of half-cells deposited by the sequential tape casting technique. A co-sintering procedure was developed for the half-cells and after cathode deposition the single cells were tested.

    Palavras-Chave: solid oxide fuel cells; anodes; casting; viscosity

  • IPEN-DOC 28524

    BOSCH-SANTOS, B. ; CABRERA-PASCA, G.A.; CORREA, E.L. ; CORREA, B.S. ; SALES, T.N.S. ; MOON, K-W.; DENNIS, C.L.; HUANG, Q.; LEAO, J.B.; LYNN, J.W.; CARBONARI, A.W. . Magnetic and structural properties of the intermetallic Ce(1−x)LaxCrGe3 series of compounds. Physical Review Materials, v. 5, n. 11, p. 114406-1 - 114406-11, 2021. DOI: 10.1103/PhysRevMaterials.5.114406

    Abstract: The Ce(1−x)LaxCrGe3 (x = 0, 0.19, 0.43, 0.58, and 1) intermetallic compound system has been investigated by magnetization measurements and neutron scattering techniques to determine the effect of La doping on the magnetic ordering and exchange interaction between Cr ions. The structural and magnetic characterization in this series was first verified by x-ray diffraction and bulk magnetization measurements. The samples exhibit the known hexagonal perovskite structure (P63/mmc space group) and have a single magnetic phase according to magnetizationmeasurements. In this paper, the ferromagnetic ordering temperature for Cr evolves smoothly from a range of 68 K to 77 K for CeCrGe3 to a range of 91 K to 96 K for LaCrGe3 as La replaces Ce. Magnetization results indicate the formation of domain walls below the transition temperature for all Ce(1−x)LaxCrGe3 systems investigated. Neutron results indicate ordered magnetic Cr moments aligned along the c axis for the x = 1 LaCrGe3 system, as well as for x = 0.19, 0.43, and 0.58, which contrasts with the x = 0 CeCrGe3 where the moments order in the ab plane.

    Palavras-Chave: magnetic properties; intermetallic compounds; magnetization; neutron dosimetry

  • IPEN-DOC 28523

    SANTOS, SILAS ; RODRIGUES, ORLANDO ; CAMPOS, LETICIA . A glance on rare earth oxides: importance, reserves, demand, applications, critical uncertainties, global economy, and zeta potential characterization. Current Smart Materials, v. 5, n. 2, p. 79-100, 2021. DOI: 10.2174/2405465805999200628095450

    Abstract: Background: Innovation mission in material science requires new approaches to form functional materials, wherein the concept of its formation begins in nano/micro scale. Rare earth oxides with general form (RE2O3; RE from La to Lu, including Sc and Y) exhibit particular proprieties, being used in a vast field of applications with high technological content since agriculture to astronomy. Despite their applicability, there is a lack of studies on the surface chemistry of rare earth oxides. Zeta potential determination provides key parameters to form smart materials by controlling interparticle forces, as well as their evolution during processing. This paper reports a study on zeta potential with emphasis on rare earth oxide nanoparticles. A brief overview of rare earths, as well as zeta potential, including sample preparation, measurement parameters, and the most common mistakes during this evaluation are reported. Methods: A brief overview of rare earths, including zeta potential, and interparticle forces are presented. A practical study on zeta potential of rare earth oxides - RE2O3 (RE as Y, Dy, Tm, Eu, and Ce) in aqueous media is reported. Moreover, sample preparation, measurement parameters, and common mistakes during this evaluation are discussed. Results: Potential zeta values depend on particle characteristics such as size, shape, density, and surface area. Besides, the preparation of samples, which involves electrolyte concentration and time for homogenization of suspensions, is extremely valuable to get suitable results. Conclusion: Zeta potential evaluation provides key parameters to produce smart materials through which interparticle forces can be controlled. Even though zeta potential characterization is mature, investigations on rare earth oxides are very scarce. Therefore, this innovative paper is a valuable contribution to this field.

    Palavras-Chave: rare earths; nanoparticles; electrolytes; colloids; ceramics; electrophoresis

  • IPEN-DOC 28522

    SANTOS, SILAS C. ; RODRIGUES JUNIOR, ORLANDO ; CAMPOS, LETICIA . Microstructure evolution of yttria compacts by powder technology. Current Smart Materials, v. 5, n. 2, p. 122-128, 2021. DOI: 10.2174/2405465805666210120102315

    Abstract: Background: Innovation in ceramic materials relies on the processing of powders. Yttria, also known as yttrium oxide, belongs to the rare-earth group (RE2O3 - RE from La to Lu, including Sc and Y). Due to the great properties and end-use of RE-based materials since agriculture until astronomy, studies on processing, sintering and microstructural evolution of RE-based materials are essential to provide new materials with improved characteristics. The aim of this paper is to obtain dense compacts of yttria by powder technology, in which the effect of sintering temperature on sample's microstructure is evaluated. Methods: Yttria powders (Y2O3) were characterized by Photon Correlation Spectroscopy (PCS), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). Cylindrical powder compacts were produced by uniaxial compaction, followed by hydrostatic compaction. Sintered samples obtained under sintering temperatures from 1350 to 1550ºC were evaluated by SEM, XRD, apparent density, and true density. Results: Cubic C-type yttria powders exhibited a mean particle size (d50) of 1.6μm, and morphology like acicular. Powder compacts (diameter x height) of 9.57mm ± 0.01 x 1.53mm ± 0.01 presented mean apparent density of 53.69% (based on free powder density). Sintered samples at 1550ºC exhibited the most densification, 65.0% related to the green density and 91.0% related to theoretical density, respectively. Conclusion: Yttria cylindrical compacts with dense microstructure, and symmetric dimensions were formed by powder technology from powders with a mean particle size of 6.51μm, by compaction methods (uniaxial and hydrostatic), followed by sintering. The most densification of samples was achieved by the sintering condition of 1550ºC for 2h, providing samples with a theoretical density of 91%. These results provide useful subsidies to advance toward full densification of yttria-based materials.

    Palavras-Chave: microstructure; yttrium; rare earths; sintering; powders; photons; correlations

  • IPEN-DOC 28521


    Abstract: Background: Nucleon transfer reactions are selective tools for nuclear physics investigations. The theoretical and computational limits affecting in the past their data analysis could be nowadays surmounted thanks to the advent of methods with refined approximations and constraints, even when heavy-ion collisions are considered. Purpose: Modern microscopic calculations of heavy-ion-induced transfer reactions combined with precise experimental data offer the chance for accurately testing different reaction models as well as the nuclear structure description of the involved nuclear states. Method: Single proton and neutron transfer reactions were measured with theMAGNEX magnetic spectrometer for the 18O+40Ca system at 15.3A MeV. Excitation energy spectra and angular differential cross section distributions were extracted. The experimental results are compared with theoretical calculations performed in distorted wave and coupled channel Born approximation. The use of a coupled channel equivalent polarization potential to effectively describe the coupling effects affecting the initial state interaction is also considered. Spectroscopic amplitudes derived from a large-scale shell model with appropriate interactions adapted for the involved nuclei are employed. Results: Our theoretical calculations are in good agreement with experimental data, without the need for any scaling factor, validating the adopted reaction and nuclear structure parameters. Moreover, under the present experimental conditions, a weak dependence of the obtained results on the choice of the reaction models was observed. Conclusions: The good agreement between experimental and theoretical results validates the reliability of the parameter sets entering the calculations. They are extracted from or tested in complementary analyses of other reaction channels under the same experimental conditions. Such a multichannel approach represents the best option to pursue a solid, comprehensive, and model-independent description of the single-nucleon transfer reactions. The successful description of the present one-nucleon transfer data is also propaedeutic to the accurate assessment, under the same theoretical description, of higher-order transfer processes, like the sequential nucleon transfer mechanisms which are in competition with the direct charge exchange reactions.

    Palavras-Chave: nucleon reactions; calcium 40; oxygen 18; calculation methods; born approximation; distorted wave theory; magnets

  • IPEN-DOC 28520


    Abstract: Background: An accurate description of the initial and final state interactions in the 18O+76Se collision is demanded by the NUMEN project. The study of single and double charge exchange nuclear reactions is the main purpose for NUMEN, since these can be used as tools to provide experimentally driven information about nuclear matrix elements of interest in the context of neutrinoless double-β decay. To date, the details of the optical potentials and nuclear response to isospin operators for many of the projectile-target systems proposed for the NUMEN double charge exchange studies are poorly known. The 18O+76Se case, here under study, is particularly relevant due to its connection with the 76Ge neutrinoless double-β decay. Purpose: In this work the authors want to characterize the initial-state interaction for the 18O+76Se reactions at 275 MeV incident energy determining the optical potential and evaluating the effect of couplings with the inelastic scattering on the elastic channel. Methods: The angular distributions of differential cross section were measured in the angular region between 4◦ and 22◦ in the center-of-mass reference frame. The cross sections were compared with theoretical calculations, that adopt different optical potentials. Coupling effects on the elastic channel were determined into the coupled channels formalism. Results: The excitation energy spectrum of the colliding nuclei and the cross section angular distributions were measured with satisfactory energy resolution. The elastic scattering cross section is not well reproduced in the full angular range explored when the optical model approach is adopted. A good agreement is found using coupled channel calculations. The initial state interaction for the 18O+76Se nuclear reactions at 275 MeV is determined. Conclusions: Coupled channels effects are crucial to obtain a good description of the measured elastic and inelastic channels cross sections, even at large transferred momenta where the optical model approach fails in reproducing the experimental data. The role of channel coupling could be relevant also in the analysis of other open reaction channels in the same collision and should be accounted for in double charge exchange analyses as well.

    Palavras-Chave: oxygen 18; selenium 76; elastic scattering; inelastic scattering; nuclear reactions

  • IPEN-DOC 28519


    Abstract: NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross-section measurements of heavy-ion induced Double Charge Exchange (DCE) reactions. Despite the fact that the two processes, namely neutrinoless double beta decay and DCE reactions, are triggered by the weak and strong interaction respectively, important analogies are suggested. The basic point is the coincidence of the initial and final state many-body wave functions in the two types of processes and the formal similarity of the transition operators. The main experimental tools for this project are the K800 Superconducting Cyclotron and MAGNEX spectrometer at the INFN-LNS laboratory. However, the tiny values of DCE cross-sections and the resolution requirements demand beam intensities much higher than those manageable with the present facility. The on-going upgrade of the INFN-LNS facilities promoted by the POTLNSa project in this perspective is intimately connected to the NUMEN project. This paper describes the solutions proposed as a result of the R&D activity performed during the recent years. The goal is to develop suitable technologies allowing for the measurements of DCE cross-section under extremely high beam intensities.

    Palavras-Chave: nuclear matrix; neutrinoless double beta decay; neutrinos; matrix elements; heavy ions; nuclear reactions; beam luminosity

  • IPEN-DOC 28518

    BUSTILLOS, OSCAR V. . O defeito de massa na espectrometria de massas. Revista Analytica, v. 19, n. 113, p. 18-21, 2021.

    Palavras-Chave: mass defect; mass spectroscopy; nuclear physics; mass number

  • IPEN-DOC 28517

    RODRIGUES, RENATA B. ; SILVA, MARIA E. da C. ; MARTINS, JOAO P. de F.. A importância do Bacillus subtilis natto na producão de uma enzima especial com propriedades medicinais: a nattoquinase. Revista Analytica, v. 19, n. 113, p. 7-13, 2021.

    Abstract: A nattoquinase é uma enzima que tem ações fibrinolítica e trombolítica que traz uma ampla aplicabilidade para o tratamento de patologias clínicas humanas. Trata-se de uma protease alcalina extraída do microorganismo não patogênico Bacillus subtilis natto. Recentes pesquisas demonstraram que o gênero Bacillus, em especial, a espécie e sua variação B. subtillis var. natto, possui propriedades prebiótica e probiótica, devido sua atividade fermentativa de grãos, tais como, soja, feijão, grão de bico, entre outros, permitindo naturalmente gerar resistência aos fitopatógenos comuns na agricultura. Dessa maneira, os alimentos que fermentam tornam-se fontes importantes que ativam o sistema imunológico no homem, previne o desenvolvimento de determinadas doenças e oferece condições ao organismo de reagir àquelas doenças que estão se manifestando. Dessa maneira, o consumo de alimentos fermentandos através do B. subtillis natto, poderá fazer parte das necessidades nutricionais, isto é, ricos em nutrientes. Essa espécie em especial, possibilita que aminoácidos e vitaminas de grãos estejam mais disponíveis, ou seja, alientos de “alta densidade nutricional” e que estão diretamente associados ao binômio saúde-doença, prevalecendo a saúde e o bem-estar das pessoas que as consomem (conhecidos como alimentos biofermentados); indicados para todas as idades, porém, ainda é pouco divulgado e, nota-se seu consumo, principalmente, adquiridos através dos hábitos alimentares, como por exemplo, pelos japoneses. A longivitude de muitos povos pode estar atrelada ao escolher alimentos saúdaveis que permitem o envelhecimento com saúde. Assim, envelhecer é uma escolha e exige esforços em todas as esferas e diretrizes: sociais, culturais, econômicas e políticas. A soja Natto, nome escolhido devido à prática do cultivo pelos povos orientais, é obtida apenas da fermentação do Bacillus subtilis natto. Ao fermentar o grão, o bacilo, como resposta da quebra de aminoácidos, produz a chamada enzima nattoquinase ou nattokinase, que possui propriedades fibrinolíticas, isto significa que possuem mecanismos fibrinolíticos. Em suma, a nattoquinase quebra as fibrinas e evita a formação de trombos (coágulos) nos vasos sanguíneos (é um trombolítico natural). Diante a leitura de artigos científicos direcionados ao assunto, o objetivo desse trabalho é relatar sobre a propriedade meritória do B. subtillis natto de produzir a enzima nattoquinase, um atenuante natural indispensável para o controle e cura de determinadas enfermidades sanguíneas.

    Palavras-Chave: enzymes; fibrinolytic agents; bacillus subtilis; thrombosis

  • IPEN-DOC 28516

    SILVA, MARCOS J. da; ALVES, WELLINGTON ; GRAEFF, CARLOS F. de O.; D'ALPINO, PAULO H.P.. Modified synthesis and physicochemical characterization of a bioglass-based composite for guided bone regeneration. The Scientific World Journal, v. 2021, p. 1-9, 2021. DOI: 10.1155/2021/4295433

    Abstract: Objectives. Bioglass composites and polymers are materials of great interest for the medical and dental areas due to their properties, combining the bioactivity of ceramic materials and the mechanical properties of polymers. The purpose of the present study was to develop and to characterize the physicochemical and morphological properties an experimental bioglass-based ternary composite composed associated with sodium carboxymethylcellulose (Na-CMC) and polyvinyl alcohol (PVA). The compatibility of functional groups with bioglass was previously evaluated. The composite was then synthesized and evaluated in terms of morphology, elemental composition, compressive strength, porosity, and bioactivity. Materials and Methods. The bioglass was previously synthesized using a sol-gel route and characterized using FTIR analysis to identify the functional groups. The bone graft composite was then synthesized associating the bioglass with PVA, surfactant Triton X, and Na-CMC. The composite was then morphologically characterized using SEM/EDS. The porosity of the composite was analyzed using µCT, which also provided the composite compression strength. The composite was then evaluated in terms of its bioactivity using SEM/EDS analyses after immersion in SBF for 12, 24, 48, and 72 h. Results. FTIR analysis confirmed, among other components, the presence of Si–O–Ca and Si–O–Si bonds, compatible with bioglass. SEM analysis exhibited a composite with a porous structure without spikes. The elemental mapping confirmed the presence of Si, Ca, and P in the composite. µCT analysis demonstrated a porous structure with 42.67% of open pores and an average compression strength of 124.7 MPa. It has also demonstrated ionic changes in the composite surface after immersion in SBF, with increasing detection of Ca and P as a function of time, highlighting its chemical bioactivity. Conclusions. It can be concluded that the proposed bioglass-based composite presents a three-dimensional, well-structured, chemically bioactive porous structure, mechanically resistant for being reinforced with polymeric phases, with promising results as a synthetic bone graft, which makes it suitable for guided bone regeneration.

    Palavras-Chave: composite materials; glass; skeleton; biological regeneration; grafts

  • IPEN-DOC 28515

    COTRIM, LUCAS P.; JOSE, MARCOS M.; CABRAL, EDUARDO L.L. . Reinforcement learning control of robot manipulator. Revista Brasileira de Computação Aplicada, v. 13, n. 3, p. 42-53, 2021. DOI: 10.5335/rbca.v13i3.12091

    Abstract: Since the establishment of robotics in industrial applications, industrial robot programming involves the repetitive and time-consuming process of manually specifying a fixed trajectory, resulting in machine idle time in production and the necessity of completely reprogramming the robot for different tasks. The increasing number of robotics applications in unstructured environments requires not only intelligent but also reactive controllers due to the unpredictability of the environment and safety measures, respectively. This paper presents a comparative analysis of two classes of Reinforcement Learning algorithms, value iteration (Q-Learning/DQN) and policy iteration (REINFORCE), applied to the discretized task of positioning a robotic manipulator in an obstacle-filled simulated environment, with no previous knowledge of the obstacles’ positions or of the robot arm dynamics. The agent’s performance and algorithm convergence are analyzed under different reward functions and on four increasingly complex test projects: 1-Degree of Freedom (DOF) robot, 2-DOF robot, Kuka KR16 Industrial robot, Kuka KR16 Industrial robot with random setpoint/obstacle placement. The DQN algorithm presented significantly better performance and reduced training time across all test projects, and the third reward function generated better agents for both algorithms.

    Palavras-Chave: control equipment; robots; manipulators; learning; artificial intelligence; neural networks

  • IPEN-DOC 28514

    NOVELLO, GUSTAVO A.M.; YAMAMOTO, HENRIQUE Y.; CABRAL, EDUARDO L.L. . An end-to-end approach to autonomous vehicle control using deep learning. Revista Brasileira de Computação Aplicada, v. 13, n. 3, p. 32-41, 2021. DOI: 10.5335/rbca.v13i3.12135

    Abstract: The objective of this work is to develop an autonomous vehicle controller inside Grand Theft Auto V game, used as a simulation environment. It is used an end-to-end approach, in which the model maps directly the inputs from the image of a car hood camera and a sequence of speed values to three driving commands: steering wheel angle, accelerator pedal pressure and brake pedal pressure. The developedmodel is composed of a convolutional neural network and a recurring neural network. The convolutional network processes the images and the recurrent network processes the speed data. Themodel learns fromdata generated by a human driver´s commands. Two interfaces are developed: one for collecting in-game training data and another to verify the performance of themodel for the autonomous vehicle control. The results show that themodel after training is capable to drive the vehicle as well as a human driver. This proves that a combination of a convolutional network with a recurrent network, using an end-to-end approach, is capable of obtaining a good driving performance even using only images and speed velocity as sensory data.

    Palavras-Chave: vehicles; automation; artificial intelligence; neural networks; learning

  • IPEN-DOC 28513

    SILVA, PAULA M. da ; SERNA, MARILENE M. ; GALEGO, EGUIBERTO ; FARIA JUNIOR, RUBENS N. . The influence of the nanostructures on the dye adsorption in dye sensitized solar cell. Research & Development in Material science, v. 15, n. 2, p. 1680-1684, 2021. DOI: 10.31031/RDMS.2021.15.000859

    Abstract: In this work, ZnO nanostructures were synthesized by two distinct routes, which consisted in grow distinct morphologies on a seed layer by Chemical Bath Deposition method (CBD) using zinc acetate dihydrate, zinc chloride, zinc sulfate heptahydrate and zinc nitrate hexahydrate as precursor solutions and Ethylenediaminetetraacetic Acid (EDTA) and ammonium chloride as complex agents. The dye Eosin Y salt was adsorbed on the ZnO nanostructures using electrophoresis. The nanostructures were characterized by Scanning Electron Microscopy (SEM), X-ray Fluorescence (XRF) and X-ray Diffraction (XRD). The amount of dye adsorbed on the film surface was evaluated by UV-vis spectrophotometry. The nanostructure prepared from the ZnAc solution presented the higher concentration of dye.

    Palavras-Chave: solar cells; zinc oxides; nanostructures; eosin; electrophoresis

  • IPEN-DOC 28512

    BENALCAZAR JALKH, E.B.; COELHO, P.G.; WITEK, L.; BERGAMO, E.T.P.; LOPES, A.C.O.; MONTEIRO, K.N.; CESAR, P.F.; GENOVA, L.A. ; LISBOA-FILHO, P.N.; ABREU, J.L.B.; CAMPOS, T.M.B.; CANTEENWALA, A.; BONFANTE, E.A.. Nanoscale physico-mechanical properties of an aging resistant ZTA composite. Journal of the Mechanical Behavior of Biomedical Materials, v. 123, p. 1-8, 2021. DOI: 10.1016/j.jmbbm.2021.104690

    Abstract: Objective: To characterize the effects of aging on the nanomechanical properties and 3D surface topographical parameters of an experimental Zirconia Toughened Alumina (ZTA) composite compared to its respective individual counterpart materials. Methods: Disk-shaped specimens comprised of three material groups were processed: 1) ZTA 70/30 (70% alumina reinforced with 30% second-generation 3Y-TZP); 2) Zpex (Second-generation 3Y-TZP), and; 3) Al2O3 (High purity Alumina) (n = 10/material, 12 × 1 mm). After synthesis, ceramic powders were pressed, the green-body samples were sintered and polished. Nanoindentation testing was performed to record elastic modulus (E) and hardness (H). Interferometry was utilized to assess 3D surface roughness parameters (Sa, Sq), while X-ray diffraction (XRD) and scanning electron microscope (SEM) assessed the crystalline content and microstructure. All tests were performed before and after simulated aging (134°C, 2.2 bar, 20 h). Statistical analyses were performed using linear mixed-model and least square difference pos-hoc tests (α = 5%). Results: XRD spectra indicated increase of monoclinic peaks for Zpex (~18%) relative to ZTA 70/30 (~2.5%) after aging. Additionally, aging did not affect the surface roughness parameters of ZTA 70/30 and Al2O3, although a significant increase in Sa was recorded for Zpex following aging (~90 nm) (p < 0.001). Al2O3 yielded the highest H and E values (H:21 GPa, E: 254 GPa), followed by ZTA 70/30 (H: 13 GPa, E: 214 GPa) and Zpex (H:11 GPa, E: 167 GPa), all significantly different (p < 0.03). Conclusion: ZTA 70/30 and Al2O3 presented high hydrothermal stability with respect to all evaluated variables, where artificial aging significantly increased the monoclinic content and surface roughness of Zpex.

    Palavras-Chave: zirconium oxides; aluminium oxides; mechanical properties; topography; microstructure; indentation testing; nanostructures

  • IPEN-DOC 28511

    DEL SORDO FILHO, GIOVANNI ; TORRECILHA, JEFFERSON K. ; SCAPIN, MARCOS A. ; OLIVEIRA, SONIA M.B.; SILVA, PAULO S.C. da . Characterization and adsorption capacity of Brazilian kaolin. Journal of Radioanalytical and Nuclear Chemistry, v. 329, n. 1, p. 61-70, 2021. DOI: 10.1007/s10967-021-07674-3

    Abstract: This study has evaluated chemical, radiological composition and determined the cation exchange capacity (CEC) for three commercially available Brazilians raw kaolins. The mineralogical characterization indicated the presence of kaolinite, kaolinite and quartz and pirophylliteas the mains mineral constitution of the samples. The results of the adsorption study indicated that the three samples did not show a significant increase in CEC due to acid or thermal treatments. However, the sample that presented the highest kaolinite content and CEC showed an effective cost benefit for water treatment application with low energy and chemical reagents spending.

    Palavras-Chave: adsorption; clays; ion exchange; kaolin; kaolinite; methylene blue; methylene blue; titration

  • IPEN-DOC 28510

    FREIRE, LUCIANO O. ; ANDRADE, DELVONEI A. de . Preliminary survey on cold fusion: it’s not pathological science and may require revision of nuclear theory. Journal of Electroanalytical Chemistry, v. 903, p. 1-10, 2021. DOI: 10.1016/j.jelechem.2021.115871

    Abstract: Since 1989 the announcement of “cold fusion” by Stanley Pons and Martin Fleishmann, “cold fusion” field has been surrounded by controversy. After three decades, this field is alive and has produced thousands of publications, most in dedicated periodic and conferences. This work aims at checking whether “cold fusion” fits in pathological science traits. For each type of experiment and year, this work counted the distinct research groups results (success or failure). Experimental results from many research groups suggest that nuclear reactions in solids are more complex than fusion (it is not only fusion) and that they need energy triggers like background radiation, meaning chemical configurations alone do not seem to generate nuclear reactions. Some types of experiments present rising trends (the field does not fit in pathological science model) and have potential to bring disruptive technologies. If confirmed, experimental results will require revisions of accepted nuclear models.

    Palavras-Chave: cold fusion; nuclear reactions; pathology; confinement; cavitation

  • IPEN-DOC 28509

    PEREIRA FILHO, N.G. ; SOUZA, R.F.B. ; RAMOS, A.S. ; ANTONIASSI, R.M. ; OLIVEIRA NETO, A. ; SPINACE, E.V. . Electro-oxidation of ethanol in acid medium using carbon-supported PtRh nanoparticles with (100) preferential orientation. International Journal of Electrochemical Science, v. 16, n. 12, p. 1-13, 2021. DOI: 10.20964/2021.12.56

    Abstract: Carbon-supported PtRh nanoparticles with preferential (100) orientation was prepared by an alcohol-reduction process using KBr as a shape directing agent. The electrocatalysts were characterized by EDX (energy-dispersive X-ray analysis), XRD (X-ray diffraction) and TEM (Transmission electron microscopy). The electro-oxidation of ethanol was studied by cyclic voltammetry and chronoamperometry at room temperature in acid medium. On-line differential mass spectrometry experiments were performed on a single cell of a direct ethanol fuel cell (DEFC) at 60 0C and the anodic effluents were analyzed by ATR-FTIR. PtRh/C (100) electrocatalyst showed cubic-like morphology and average nanoparticles size of 8 nm and provided superior DEFC performance (density power per Pt active area) and CO2 selectivity compared to polycrystalline PtRh/C and commercial Pt/C electrocatalysts.

    Palavras-Chave: nanoparticles; platinum alloys; rhodium alloys; electrocatalysts; ethanol; fuel cells

  • IPEN-DOC 28508

    OLIVEIRA, JOAO E. ; SUZUKI, MIRIAM F. ; DAMIANI, RENATA; LIMA, ELIANA R.; AMARAL, KLEICY C. ; SANTOS, ANDERSON M.S.; MAGALHAES, GERALDO S.; FAVERANI, LEONARDO P.; PEREIRA, LUIS A.V.D.; BARTOLINI, PAOLO . Synthesis of human bone morphogenetic protein-2 (hBMP-2) in E. coli periplasmic space: its characterization and preclinical testing. Cells, v. 10, n. 12, p. 1-16, 2021. DOI: 10.3390/cells10123525

    Abstract: Human BMP-2, a homodimeric protein that belongs to the TGF- family, is a recognized osteoinductor due to its capacity of inducing bone regeneration and ectopic bone formation. The administration of its recombinant form is an alternative to autologous bone grafting. A variety of E. coli-derived hBMP-2 has been synthesized through refolding of cytoplasmic inclusion bodies. The present work reports the synthesis, purification, and characterization of periplasmic hBMP-2, obtained directly in its correctly folded and authentic form, i.e., without the initial methionine typical of the cytoplasmic product that can induce undesired immunoreactivity. A bacterial expression vector was constructed including the DsbA signal peptide and the cDNA of hBMP-2. The periplasmic fluid was extracted by osmotic shock and analyzed via SDS-PAGE, Western blotting, and reversed-phase high-performance liquid chromatography (RP-HPLC). The purification was carried out by heparin affinity chromatography, followed by high-performance size-exclusion chromatography (HPSEC). HPSEC was used for qualitative and quantitative analysis of the final product, which showed >95% purity. The classical in vitro bioassay based on the induction of alkaline phosphatase activity in myoblastic murine C2C12 cells and the in vivo bioassay consisting of treating calvarial critical-size defects in rats confirmed its bioactivity, which matched the analogous literature data for hBMP-2.

    Palavras-Chave: bone tissues; proteins; plasmids; critical size; defects

  • IPEN-DOC 28507

    DANTAS, A.C. ; SILVA, A.T. . A method for uncertainty and sensitivity analysis in fuel performance codes. Brazilian Journal of Radiation Sciences, v. 9, n. 3, p. 1-18, 2021. DOI: 10.15392/bjrs.v9i3.1700

    Abstract: The present study proposes a method for the execution of uncertainty and sensitivity analysis on TRANSURANUS code, adapted for the use of stainless steel AISI-348 as the cladding material for a PWR reactor fuel rod, thus allowing to determine which input data are more relevant to the TRANSURANUS models, as well as a confidence interval for the results. The analysis was made through Monte Carlo sampling, where input values related to the geometry and composition of the fuel rod were taken from a normal distribution truncated around fabrication tolerance values. The generated samples were used as TRANSURANUS input data, and after numerous executions of the code, the results pertaining to the fuel center line temperature, fuel rod inner pressure and cladding strains were used to obtain a confidence interval and to make a variance-based sensitivity analysis, showing that the models used in TRANSURANUS are additive in nature, and input interactions are not relevant to the code.

    Palavras-Chave: cladding; data covariances; fuel rods; monte carlo method; nuclear fuels; performance; pwr type reactors; sensitivity analysis; stainless steel-348; t codes

  • IPEN-DOC 28506

    BEZERRA, ANDRE de S. ; ZEITUNI, CARLOS A. ; ROSTELATO, MARIA E.C.M. . Characterization of patients with prostate cancer care at a reference hospital in the state of Tocantins, suitable for brachytherapy. Brazilian Journal of Radiation Sciences, v. 9, n. 3, p. 1-15, 2021. DOI: 10.15392/bjrs.v9i3.1691

    Abstract: Observation and identification of predictive factors for results and morbidity are essential in the ideal selection of patients who can use brachytherapy as a treatment modality for prostate cancer. Thus, the objective of this research is to characterize the population of patients with prostate cancer treated at the General Public Hospital of Palmas in 2015, in the state of Tocantins. The method used was quantitative, with the characteristics of a retrospective, transversal and descriptive analysis. Held in the largest state health unit, the General Public Hospital of Palmas that, despite its large dimensions, lives with the main problems of the Unified Health System, such as overcrowding and shortages. It was found that most of the patients seen corresponded to the age of 70 to 79 years, making 45%, followed by patients aged between 60 and 69 years, with 33%. Most of the individuals attended were from the state of Tocantins, but some lived in an adjacent city in the state of Pará. Data related to the Gleason score showed that there was a predominance of levels 6 and 7 indicating intermediate grade tumors, considering that the most of the observed population was older. It was concluded that the analyzed patients had a predominant staging of CaP II and III, thus most of the individuals, 23 of the 35 analyzed, were not able to undergo brachytherapy due to the high degree of disease staging.

    Palavras-Chave: brachytherapy; carcinomas; disease incidence; elderly people; prostate; statistical data

  • IPEN-DOC 28505

    GOMES, FERNANDA C.G.; NAURATH, CHRISTIAN; AZEVEDO, LUCIANE H.; ZEZELL, DENISE M. . Photobiomodulation therapy to treat neuropathic oral pain after contagion by COVID-19. Brazilian Dental Science, v. 24, n. 4, Suppl 1, p. 1-5, 2021. DOI: 10.4322/bds.2021.e2962

    Abstract: Objective: The purpose of this short communication is to show that although photobiomodulation in the treatment of neurophathic oral pain after COVID-19 contagion could be an option, photobiomodulation is not a new technique. PBMT was used with different protocols and pain was assessed using VAS (visual analogue scale - 0 until 10) before and after the consultation. Results: Evolution of VAS during the sessions showed a decrease in painful symptomatology as treatment was performed. Conclusion: Based on the results obtained in the present case report, we concluded that PBMT with the parameters used in this clinical case was an effective, noninvasive and a new option of treatment for neuralgia resulting from COVID-19.

    Palavras-Chave: light emitting diodes; therapy; coronaviruses; nerves; pain

  • IPEN-DOC 28504

    SCARDINI, IANDARA de L.; ZEZELL, DENISE M. ; MARQUES, JULIANA L.C.; FREIRE, LAILA G.; SANTOS, MARCELO dos. Surface profile of different heat-treated nickel-titanium files before and after root canal preparation. Brazilian Dental Journal, v. 32, n. 6, p. 8-15, 2021. DOI: 10.1590/0103-6440202104045

    Abstract: The aim of this study was to evaluate surface wear, presence of microcracks and surface irregularities of WaveOne (WO) and WaveOne Gold (WOG) instruments before and after multiple uses. Eight Primary instruments of the WO and WOG systems were evaluated, each one was used to prepare six mesial canals of extracted human mandibular molars. The surface of the instruments was evaluated before use (T0), after instrumentation of three (T1) and six (T2) root canals. Surface wear was analyzed using a three-dimensional optical profiler and the presence of microcracks and surface irregularities were evaluated using a tabletop scanning electron microscopy. The Friedman test was used to assess surface wear and Kruskal-Wallis test to evaluate the presence of microcracks and surface irregularities, with a 5% significance level. There was a significant increase in wear in both groups at T2, compared to T0 (p=0.0003). The surface wear after instrumentation of six canals (T2-T0) was statistically greater in the WOG group, than in the WO group (p=0.02), where the presence of microcracks was significantly greater and increased after multiple uses (p<0.05). The presence of surface irregularities in the cutting blade before and after use was statistically greater in the WOG group than WO group (p<0.05). Wear of the cutting blade, microcracks and surface irregularities were observed on the surface topography of all the instruments after multiple uses. These surface changes may affect the cutting efficiency of WOG files and increase the risk of fracture of WO files.

    Palavras-Chave: nickel; titanium; dentistry; bone tissues

  • IPEN-DOC 28503

    BASSO, LUANA S.; MARANI, LUCIANO; GATTI, LUCIANA V. ; MILLER, JOHN B.; GLOOR, MANUEL; MELACK, JOHN; CASSOL, HENRIQUE L.G.; TEJADA, GRACIELA; DOMINGUES, LUCAS G. ; ARAI, EGIDIO; SANCHEZ, ALBER H.; CORREA, SERGIO M.; ANDERSON, LIANA; ARAGAO, LUIZ E.O.C.; CORREIA, CAIO S.C. ; CRISPIM, STEPHANE P.; NEVES, RAIANE A.L.. Amazon methane budget derived from multi-year airborne observations highlights regional variations in emissions. Communications Earth & Environment, v. 2, n. 1, p. 1-13, 2021. DOI: 10.1038/s43247-021-00314-4

    Abstract: Atmospheric methane concentrations were nearly constant between 1999 and 2006, but have been rising since by an average of ~8 ppb per year. Increases in wetland emissions, the largest natural global methane source, may be partly responsible for this rise. The scarcity of in situ atmospheric methane observations in tropical regions may be one source of large disparities between top-down and bottom-up estimates. Here we present 590 lower-troposphere vertical profiles of methane concentration from four sites across Amazonia between 2010 and 2018. We find that Amazonia emits 46.2 ± 10.3 Tg of methane per year (~8% of global emissions) with no temporal trend. Based on carbon monoxide, 17% of the sources are from biomass burning with the remainder (83%) attributable mainly to wetlands. Northwest-central Amazon emissions are nearly aseasonal, consistent with weak precipitation seasonality, while southern emissions are strongly seasonal linked to soil water seasonality. We also find a distinct east-west contrast with large fluxes in the northeast, the cause of which is currently unclear.

    Palavras-Chave: methane; emission; ecological concentration; climates; amazon river

  • IPEN-DOC 28502

    AZEVEDO JUNIOR, JAIR ; BARROSO, ANTONIO C. de O. ; MONTEIRO, CARLOS A. . An expedited model to appraise project management office value. International Journal of Development Research, v. 11, n. 12, p. 52699-52704, 2021. DOI: 10.37118/ijdr.23690.12.2021

    Abstract: This study presents the development of a practical model to evaluate the perception of Project Management Office value as seen by project managers. Questions compiled through literature review and interaction with project managers are presented first. An exploratory factor analysis was used to define the best grouping of the items within factors that could be interpretable under the reviewed literature. To evaluate the efficacy of the proposed model, we performed a confirmatory analysis using the Partial Least Square variant of the Structural Equation Modeling. The model demonstrated good convergent validity, very good discriminant validity, and reliability. In addition, the values of its determination and path coefficients were well above the classically recommended values and were also statistically significant. Within the limitations of the tests we done thus far, it appears that a practical, robust, and potentially functional predictive model was achieved.

    Palavras-Chave: program management; organizational models; cost; planning

  • IPEN-DOC 28501

    ALMEIDA, JORGE V. de; GU, XIAOQIANG; MOSSO, MARBEY M.; SARTORI, CARLOS A.F. ; WU, KE. Nonlinear metamaterial lenses for inductive power transmission systems using Duffing-resonator based unit cells. J, v. 4, n. 4, p. 727-748, 2021. DOI: 10.3390/j4040050

    Abstract: Metamaterials (MTMs) based on a periodic array of resonant coils have been shown to behave as μ-negative (MNG), enabling the focusing of magnetic flux. The phenomenon has been deployed by designers to boost the efficiency of many inductively coupled systems, such as magnetic resonance imaging, underwater and underground communications, and charging base stations (CBS) for consumer electronics and implanted devices. However, due to their dependency on high-Q unit cells, linear MNG-like MTMs have limited bandwidth, restricting their use in many applications, notably in near-field simultaneous wireless information and power transmission (NF-SWIPT) systems. To improve the tight constraints of the amplitude-bandwidth trade-off of artificial magnetic lenses, this paper presents a theoretical analysis of nonlinear MTMs based on a lattice of Duffing resonators (DRs). Additionally, it introduces a criterium for the quantification and evaluation of the amplitude-bandwidth enhancement. The analytical results are based on a circuit model and further verified by numerical simulations using commercial software. The preliminary findings in this paper open up possibilities for nonlinear MTM lenses and can be applied to enhance the linear amplitude-bandwidth limit.

    Palavras-Chave: metamaterials; resonators; electromagnetic lenses; power transmission

  • IPEN-DOC 28500

    MAZZILLI, BARBARA P. ; LAVIERI, LETICIA G.S. ; SOARES, JOSIANE S. ; ROCHA, FLAVIO R. ; ANGELINI, MATHEUS ; FAVARO, DEBORAH I.T. . Trace and major elements, natural and artificial radionuclides assessment in bottom sediments from Tietê River basin, São Paulo State, Brazil: part III. Journal of Radioanalytical and Nuclear Chemistry, v. 331, n. 1, p. 129-144, 2022. DOI: 10.1007/s10967-021-08094-z

    Abstract: This paper aims at quantifying natural and artificial radionuclides, trace and major elements in sediments collected along the Tietê River basin. The results obtained for Cd, Cr, Cu, Ni and Zn, indicated that the region of “High Tietê” is highly polluted, followed by the region of “Middle Tietê” and the region of “Low Tietê” does not present evidence of contamination. The natural radionuclide concentrations were of the same order of magnitude of world average values and can be defined as basal levels of the region. Cesium-137 activity concentration ranged from 0.22 ± 0.08 Bq kg−1 to 0.96 ± 0.12 Bq kg−1.

    Palavras-Chave: rivers; sediments; contamination; elements; heavy metals; radioisotopes; trace amounts

  • IPEN-DOC 28499

    MUCCILLO, REGINALDO ; FLORIO, DANIEL Z. de; FONSECA, FABIO C. ; CARVALHO, SABRINA G.M. ; MUCCILLO, ELIANA N.S. . Electric field-assisted sintering anode-supported single solid oxide fuel cell. International Journal of Applied Ceramic Technology, v. 19, n. 2, p. 906-912, 2022. DOI: 10.1111/ijac.13871

    Abstract: Cosintering (La0.84Sr0.16MnO3 thin-film cathode/ZrO2: 8 mol% Y2O3 thin-film solid electrolyte/55 vol.% ZrO2:8 mol% Y2O3 + 45 vol.% NiO anode, ϕ = 12 × 1.5 mm thick pellet) was achieved by applying an electric field for 5 min at 1200°C. Impedance spectroscopy measurements of the anode-supported three-layer cell show an improvement of the electrical conductivity in comparison to that of a conventionally sintered cell. The scanning electron microscopy images of the cross-sections of electric field-assisted pressureless sintered cells show a fairly dense electrolyte and porous anode and cathode. Joule heating, resulting from the electric current due to the application of the AC electric field, is suggested as responsible for sintering. Dilatometric shrinkage curves, electric voltage and current profiles, impedance spectroscopy diagrams, and scanning electron microscopy micrographs show how anode-electrolyte-cathode ceramic cells can be cosintered at temperatures lower than the usually required.

    Palavras-Chave: solid oxide fuel cells; dilatometry; electric fields; electric impedance; sintering

  • IPEN-DOC 28498

    HADDOUT, S.; GIMILIANI, G.T. ; PRIYA, K.L.; HOGUANE, A.M.; CASILA, J.C.C.; LJUBENKOV, I.. Microplastics in surface waters and sediments in the Sebou Estuary and Atlantic Coast, Morocco. Analytical Letters, v. 55, n. 2, p. 256-268, 2022. DOI: 10.1080/00032719.2021.1924767

    Abstract: Microplastics (MPs) are emerging contaminants and present risks to human and environmental health. Microplastic levels were examined in sediment and surface water samples at stations along the Sebou Estuary and Atlantic Coast of Morocco. The microplastic abundance, distribution, and characteristics were characterized. The microplastics were separated into fragments, fibers, films, and granules. The results at all stations showed that the microplastic abundance in water samples ranged from 10 to 168 particles/m³, whereas in the sediment samples, the levels were from 10 to 300 particles/kg. Stations adjacent to Kenitra City showed significantly high levels of microplastics (p < 0.001) compared with the Atlantic Coast, likely due to population density and human activity. The majority of the detected microplastics was from 0.1 to 0.5 mm, followed by 0.5 to 1 mm. The predominant shape in water and sediments were fragments. The results for the type, size, and color of the microplastics suggest the Sebou Estuary is a hotspot on the Atlantic Coast. The results of this study may contribute to increased awareness and better implementation of solid waste management plans, especially at Kenitra City, to protect the biologically diverse ecosystem of the Moroccan Estuary and Atlantic Coast.

    Palavras-Chave: water pollution; surface waters; sediments; plastics; estuaries; environmental impacts

  • IPEN-DOC 28437

    SONA FILHO, CELSO R. ; CARVALHO, FLAVIO M. de S.; GUEDES-SILVA, CECILIA C. . Mechanical properties and in vitro bioactivity of silicon nitride ceramics with SiO2, CaO, and MgO additions. Journal of Biomedical Materials Research Part B: Applied Biomaterials, v. 110, n. 3, p. 507-516, 2022. DOI: 10.1002/jbm.b.34930

    Abstract: Silicon nitride ceramics with SiO2, CaO, and MgO as sintering aids were investigated in view of biomedical applications. In the current study, samples with four different compositions were pressureless sintered at 1750°C for 1 h under a nitrogen atmosphere. The samples were evaluated concerning densification, microstructure, mechanical properties, and in vitro bioactivity. Microstructures with elongated β-Si3N4 grains dispersed in an intergranular phase and with densities from 78.77 to 97.14% of the theoretical density were obtained. Higher contents of SiO2 resulted in the best densification and mechanical properties. Besides, replacements of CaO by MgO in the initial compositions affected Young's modulus and in vitro bioactivity. Considering the samples with relative density higher than 94.14%, those with lower values of Young's modulus had lower SiO2/MgO ratios. After immersion in SBF (Simulated Body Fluid), the samples with high porosity and/or partial replacements of CaO by MgO had their surfaces coated with a layer rich in calcium and phosphorus, morphologically similar to hydroxyapatite. Hence, producing silicon nitride ceramics with the potential to be used as orthopedic implants must consider ideal amounts of additives. In this article, the best combination of mechanical properties and mineralization capability was reached by the composition with low content of MgO, and high content of SiO2 and CaO.

    Palavras-Chave: ceramics; mechanical properties; silicon nitrides; silicon oxides; calcium oxides; magnesium oxides

  • IPEN-DOC 28436

    CAETANO, GABRIELA A.; GONORING, TIAGO B.; COELHO, LUCAS M.; LUZ, TEMISTOCLES de S.; ROSSI, JESUALDO L. ; ORLANDO, MARCOS T.D.A.. Mechanical properties study of a duplex stainless steel weld using physical simulation and work hardening models. Journal of Materials Engineering and Performance, v. 31, n. 1, p. 113-127, 2022. DOI: 10.1007/s11665-021-06155-8

    Abstract: Transporting substances with high radioactivity used in nuclear medicine is strategic. Lean duplex stainless steel UNS S32304 is a candidate for external construction of a cask for transporting radioactive material. Thin sheet lean duplex stainless steel specimens were welded by autogenous TIG processing (tungsten inert gas) in order to avoid neutron activation of the filler metal. Post-welding heat treatments were studied considering a possible scenario of fire or crash during transportation. The metallographic analysis indicated that post-welding heat treatments promoted a change in austenitic phase content in the fusion zone. An analysis of the stress-strain curves using work hardening models revealed that only the Voce and Hockett–Sherby models presented goodness-of-fit to the experimental data. It was demonstrated that the parameters of both models are correlated to the volumetric austenitic phase content present in the fusion zone, being equivalent to the quantification of the bulk phase. This work proposes a new direct evaluation methodology for volumetrically quantifying phases using both mathematical work hardening models fitted to the experimental data from stress-strain curves.

    Palavras-Chave: stainless steels; radioactive materials; transport; metallography

  • IPEN-DOC 28435

    JUNIOR, ALEXANDRE F.; RIBEIRO, CHARLENE A.; LEYVA, MARIA E.; MARQUES, PAULO S.; SOARES, CARLOS R.J. ; QUEIROZ, ALVARO A.A. de . Biophysical properties of electrospun chitosan-grafted poly(lactic acid) nanofibrous scaffolds loaded with chondroitin sulfate and silver nanoparticles. Journal of Biomaterials Applications, v. 36, n. 6, p. 1098-1110, 2022. DOI: 10.1177/08853282211046418

    Abstract: The aim of this work was to study the biophysical properties of the chitosan-grafted poly(lactic acid) (CH-g-PLA) nanofibers loaded with silver nanoparticles (AgNPs) and chondroitin-4-sulfate (C4S). The electrospun CH-g-PLA:AgNP:C4S nanofibers were manufactured using the electrospinning technique. The microstructure of the CH-g-PLA:AgNP:C4S nanofibers was investigated by proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and Fourier transform infrared (ATR-FTIR) spectroscopy. ATR-FTIR and 1H-NMR confirm the CH grafting successfully by PLA with a substitution degree of 33.4%. The SEM measurement results indicated apparently smooth nanofibers having a diameter range of 340 ± 18 nm with porosity of 89 ± 3.08% and an average pore area of 0.27 μm2. UV-Vis and XRD suggest that silver nanoparticles with the size distribution of 30 nm were successfully incorporated into the electrospun nanofibers. The water contact angle of 12.8 ± 2.7° reveals the hydrophilic nature of the CH-g-PLA:AgNP:C4S nanofibers has been improved by C4S. The electrospun CH-g-PLA:AgNP:C4S nanofibers are found to release ions Ag+ at a concentration level capable of rendering an antimicrobial efficacy. Gram-positive bacteria (S.aureus) were more sensitive to CH-g-PLA:AgNP:C4S than Gram-negative bacteria (E. coli). The electrospun CH-g-PLA:AgNP:C4S nanofibers exhibited no cytotoxicity to the L-929 fibroblast cells, suggesting cytocompatibility. Fluorescence microscopy demonstrated that C4S promotes the adhesion and proliferation of fibroblast cells onto electrospun CH-g-PLA:AgNP:C4S nanofibers.

    Palavras-Chave: silver; nanoparticles; nanofibers; lactic acid

  • IPEN-DOC 28434

    ZAHARESCU, TRAIAN; MATEESCU, CARMEN; DIMA, ANDREEA; VARCA, GUSTAVO H.C. . Evaluation of thermal and radiation stability of EPDM in the presence of some algal powders. Journal of Thermal Analysis and Calorimetry, v. 147, n. 1, p. 327-336, 2022. DOI: 10.1007/s10973-020-10319-4

    Abstract: In this paper, ecological-friendly materials based on ethylene–propylene–diene terpolymer (EPDM) with improved thermal and radiation stabilities by Chlorella vulgaris (CV) and Spirulina platensis (SP) powders were investigated by complementary procedures: FTIR spectroscopy and isothermal and nonisothermal chemiluminescence (CL). The stabilization potential of microalgae was evaluated at several degrees of γ-radiolysis by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while the polymer resistances were studied on a large range of algal concentrations (1, 3, 5 and 10 mass%). The carbonyl and hydroxyl indices of all degraded EPDM formulations were found to be two times smaller in the presence of algal powders, if compared to the pristine material. Some dissimilarities between the oxidation development in pristine and modified EPDM appeared, especially in unirradiated samples. The activation energies required for the oxidation of EPDM and the lifetime of these samples at various temperatures between room temperature and 100 °C were calculated. The antioxidant compounds existing in the studied microalgae proved a significant influence on the stability of EPDM, mainly in the presence of SP, which was confirmed by the activation energies calculated from our CL results. The investigation of cycling thermal degradation revealed the obvious contribution of additives towards delaying EPDM ageing.

    Palavras-Chave: antioxidants; chlorella; ethylene propylene diene polymers; stability; thermal analysis; radiations

  • IPEN-DOC 28433

    NUNES, R.F.; TOMINAGA, F.K. ; BORRELY, S.I. ; TEIXEIRA, A.C.S.C.. UVA/persulfate-driven nonylphenol polyethoxylate degradation: effect of process conditions. Environmental Technology, v. 43, n. 2, p. 286-300, 2022. DOI: 10.1080/09593330.2020.1786166

    Abstract: UV/persulfate (UV/PS) technologies have gained increased attention as efficient alternatives for removing pollutants from different classes, although processes based on the UVA-driven S2O2−8 (PS) activation have not yet been discussed in the literature for the removal of the nonionic surfactant nonylphenol polyethoxylate (NPEO). The present study investigated the simultaneous effect of the initial persulfate concentration ([PS]0) and specific photon emission rate (EP,0) on NPEO degradation by UVA/PS following a Doehlert experimental design. The results for [NPEO]0 = (4.65 ± 0.15) mg L−1 indicated more than 97.8% NPEO removal after 2 h, with pseudo first-order specific degradation rate (kobs) of 0.0320 min−1, for [PS]0 = 7.75 mmol L−1 and EP,0 = 0.437 μmol photons L−1 s−1. Under these conditions, NPEO half-life time was about 22 min, and the EC50-48 h (% v/v) values for Daphnia similis before and after treatment did not differ significantly. Higher values of EP,0 would influence NPEO removal for [PS]0 not higher than 8–10 mmol L−1, although lower degradation efficiencies were obtained with higher [NPEO]0 or real wastewater, except for longer reaction times. Additionally, UVA/PS showed to be efficient for tensoactivity removal, despite the negligible total organic carbon (TOC) removal achieved. Finally, UVC and UVA resulted in NPEO degradation higher than 96% and similar tensoactivity removals when UVA/PS was conducted under optimal conditions ([PS]0 = 10 mmol L−1; EP,0 = 0.324 μmol photons L−1 s−1), suggesting that UVA radiation available in solar light could be advantageously employed for NPEO removal at concentrations usually found in wastewater.

    Palavras-Chave: surfactants; pollution control; biodegradation; persulfates; ultraviolet radiation; surface tension

  • IPEN-DOC 28432

    ALVES, ALINE V.; FERRAZ, MARIANA A.; MORENO, BEATRIZ B.; NOBRE, CAIO R.; ANTUNES, RENATA M.; PUSCEDDU, FABIO H.; BORDON, ISABELLA C. da C.L.; FAVARO, DEBORAH I.T. ; COTRIM, MARYCEL E.B. ; CHOUERI, RODRIGO B.. Microscale Toxicity Identification Evaluation (TIE) for interstitial water of estuarine sediments affected by multiple sources of pollution. Environmental Science and Pollution Research, v. 29, p. 10122-10137, 2022. DOI: 10.1007/s11356-021-15389-x

    Abstract: Estuaries in the world are affected by different contamination sources related to urbanisation and port/industrial activities. Identifying the substances responsible for the environmental toxicity in estuaries is challenging due to the multitude of stressors, both natural and anthropogenic. The Toxicity Identification and Evaluation (TIE) is a suitable way of determining causes of toxicity of sediments, but it poses difficulties since its application is labour intensive and time consuming. The aimof this study is to evaluate the diagnosis provided by a TIE based on microscale embryotoxicity tests with interstitial water (IW) to identify toxicants in estuarine sediments affected by multiple stressors. TIE showed toxicity due to different combinations of metals, apolar organic compounds, ammonia and sulphides, depending on the contamination source closest to the sampling station. The microscale TIE was able to discern different toxicants on sites subject to different contamination sources. There is good agreement between the results indicated in the TIE and the chemical analyses in whole sediment, although there are some disagreements, either due to the sensitivity of the test used, or due to the particularities of the use of interstitial water to assess the sediment toxicity. The improvement of TIE methods focused on identifying toxicants in multiple-stressed estuarine areas are crucial to discern contamination sources and subsidise management strategies.

    Palavras-Chave: toxicity; sediments; coastal waters; water pollution; embryos; ontogenesis; ontogenesis

  • IPEN-DOC 28431

    SANTOS, S.C. ; RODRIGUES JUNIOR, O. ; CAMPOS, L.L. . Colloidal processing of thulium-yttria microceramics. Journal of Physics and Chemistry of Solids, v. 161, p. 1-10, 2022. DOI: 10.1016/j.jpcs.2021.110420

    Abstract: The development of new dosimetric materials is essential for the safe and effective use of nuclear technology. In the present study, an eco-friendly bio-prototyping approach was developed for preparing thulium-yttria microceramics with potential applications in radiation dosimetry. Micro-powder compacts were obtained by casting colloidal thulium-yttria suspensions prepared with 20 vol% particles in thin-walled tube templates. Samples were sintered at 1600 °C for 2 h under the environmental pressure and atmosphere to obtain thulium-yttria microceramics with dimensions of 3.33 ± 0.01 mm × 2.27 ± 0.01 mm (height × diameter), as well as a cubic C-type structure, pycnometric density of 4.79 g cm−3 (95.61% theoretical density), and surface microstructure comprising hexagon-like grains bonded at the boundaries. The use of thulium as an activator of yttria greatly improved the electron paramagnetic resonance (EPR) response of the microceramics, where the main EPR peak (p1) was recorded at 351.24 mT and the g factor was 2.0046. The innovative findings obtained in this study may facilitate the production of new solid state dosimeters.

    Palavras-Chave: colloids; ceramics; dosimetry; rare earths; yttrium; thulium oxides

  • IPEN-DOC 28430

    PALHARIM, PRISCILA H.; FUSARI, BEATRIZ L.D. dos R.; RAMOS, BRUNO; OTUBO, LARISSA ; TEIXEIRA, ANTONIO C.S.C.. Effect of HCl and HNO3 on the synthesis of pure and silver-based WO3 for improved photocatalytic activity under sunlight. Journal of Photochemistry and Photobiology A: Chemistry, v. 422, p. 1-12, 2022. DOI: 10.1016/j.jphotochem.2021.113550

    Abstract: Heterogeneous photocatalysis have been considered an important and efficient alternative water and wastewater treatment process. In this area, different semiconductors, such as tungsten trioxide, have been investigated aiming to enhance photocatalytic performance. WO3 is known to be an efficient material with high stability in acidic conditions. In the present work, pure and Ag/AgCl-doped WO3 photocatalysts were synthesized by a simple hydrothermal method. A discussion of the effects of two pH-controlling agents, HCl and HNO3, in the final properties of the catalyst is reported for the first time. The materials were characterized by XRD, BET, SEM, EDS and UV–vis DRS. All catalysts showed similar or enhanced band gap values compared to a standard photocatalyst benchmark (TiO2 P25). The type of acid did not lead to significant differences in morphology or photocatalytic activity of undoped catalysts. In contrast, doped catalysts prepared using HCl resulted in particles of flower-like morphology, with higher uniformity and slightly narrower band gap values. Furthermore, the use of HCl in the synthesis of silver-doped WO3 resulted in catalysts containing AgCl, while Ag0 was the major dopant species when HNO3 was used. All materials exhibited good photocatalytic activity, with a maximum of 75.4% acetaminophen degradation under simulated sunlight achieved by the catalyst prepared with HCl and doped with 5% Ag-equivalent. For this catalyst, the degradation kinetics was found to be consistent with the Langmuir-Hinshelwood (L−H) model, and reusability tests showed no significant decrease in the degradation efficiency after four cycles. Finally, the effects of different scavengers suggest that O2•− species play a major role in acetaminophen degradation with the material containing WO3, Ag and AgCl.

    Palavras-Chave: photocatalysis; doped materials; hydrothermal synthesis; waste water; water treatment; heterogeneous catalysis

  • IPEN-DOC 28429

    CATANHEIRA, BRUNA; OTUBO, LARISSA ; OLIVEIRA, CRISTIANO L.P.; MONTES, ROSA; QUINTANA, JOSE B.; RODIL, ROSARIO; BROCHSZTAIN, SERGIO; VILAR, VITOR J.P.; TEIXEIRA, ANTONIO C.S.C.. Functionalized mesoporous silicas SBA-15 for heterogeneous photocatalysis towards CECs removal from secondary urban wastewater. Chemosphere, v. 287, Part 1, p. 1-11, 2022. DOI: 10.1016/j.chemosphere.2021.132023

    Abstract: The photocatalytic activity of TiO2 nanoparticles (NPs) supported on mesoporous silica SBA-15 (TiO2/SBA-15) was evaluated for the photodegradation of sulfadiazine (SDZ), as target contaminant of emerging concern (CEC), using either pure water solutions (PW) or a real secondary urban wastewater (UWW) spiked with SDZ. For this purpose, TiO2/SBA-15 samples with 10, 20 and 30% TiO2 (w/w) were prepared by the sol-gel post synthetic method on pre-formed SBA-15, using titanium (IV) isopropoxide as a precursor. The TiO2/SBA-15 materials were characterized by HRTEM, SAXS and XRD, nitrogen adsorption isotherms and UV–vis diffuse reflectance spectroscopy. TiO2 NPs were shown to be attached onto the external surface, decorating the SBA-15 particles. The TiO2/SBA-15 catalysts were active in SDZ photodegradation using the annular FluHelik photoreactor, when irradiated with UVA light. The 30% TiO2/SBA-15 sample presented the best performance in optimization tests performed using PW, and it was further used for the tests with UWW. The photocatalytic activity of 30% TiO2/SBA-15 was higher (56% SDZ degradation) than that of standard TiO2–P25 (32% SDZ degradation) in the removal of SDZ spiked in the UWW ([SDZ] = 2 mg L−1). The photodegradation of SDZ with 30% TiO2/SBA-15 eached 90% for UWW spiked with a lower SDZ concentration ([SDZ] = 40 μg L−1). Aside of SDZ, a suit of 65 other CECs were also identified in the UWW sample using LC-MS spectrometry. A fast-screening test showed the heterogeneous photocatalytic system was able to remove most of the detected CECs from UWW, by either adsorption and/or photocatalysis.

    Palavras-Chave: oxidation; photocatalysis; silica; porous materials; sulfonamides

  • IPEN-DOC 28428

    NASCIMENTO, ERIBERTO O. do; BECATTI, MATHEUS J.P.; CALDAS, LINDA V.E. ; OLIVEIRA, LUCAS N. de . Design of Experiments (DoE) method for solar protective films via UV–Vis and NIR spectrophotometry measurements. Journal of Luminescence, v. 242, p. 1-10, 2022. DOI: 10.1016/j.jlumin.2021.118558

    Abstract: Individual dosimetry and the shielding of sun rays are needed for people in homes, at workplaces and vehicles when exposed to Ultraviolet Radiation (UVR) and/or Infrared Radiation (IR). Usually, the efficacy of Solar Protective Films (SPF) has been recognized as an important public health concern. So, this work aimed to verify, using the Design of Experiments (DoE) and Multiple Linear Regression (MLR) methods, the evaluation of solar films using the UV–Vis and NIR (Near Infrared) spectrophotometry technique for absorbance readings. In addition, the significance of the SPF manufacturing origin and glass color were evaluated. Four types of SPF, named G05, G20, G35 and WB, were tested and layered within dark and light glasses. The absorbance readings were used in a 2k factorial design analysis, then the one-way ANOVA Test and the Bonferroni Test were used to assess the statistical significance of each factor. The results showed that the statistical error, using the Root Mean Square Percentage Error (RMSPE) and the Mean Absolute Percentage Error (MAPE) methods, showed values less than 0.014% between the measured and the predicted ones, indicating excellent accuracy. In conclusion, DoE and MLR methods are suitable to be used in the investigation of the association between SPF and glass materials.

    Palavras-Chave: solar radiation; radiation protection; ultraviolet radiation; spectrophotometry

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

Autor: Maprelian

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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.

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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.