Abstract: The Pd/C, PdRh(50:50)/C and PdSn(50:50)/C nanomaterials were used as electrocatalysts for ethanol (EtOH) oxidation in Direct Ethanol Fuel Cell (DEFC) in an alkaline medium. This work aims to provide a complete physical characterization of the nanomaterials, elucidate the bifunctional mechanism concerning ethanol oxidation reaction and understand the influence of carbon e metal bonding in the electrochemical activity. These nanomaterials were investigated by X-ray photoelectron spectroscopy (XPS) and revealed that the atomic percentage of the surface is different of those obtained by Energy Dispersive X-ray spectroscopy (EDS). Raman spectroscopy showed a bonding between palladium and carbon atoms which can play a decisive role in the performance of the materials. Attenuated Total Reflectance technique coupled to the Fourier Transform Infrared spectroscopy (ATR-FTIR) made possible to investigate the oxidation products originated by the ethanol oxidation, and all the electrocatalysts showed the presence of acetaldehyde, carbonate ions, acetate and carbon dioxide, suggesting that the mechanism of oxidation is incomplete. Among all the nanomaterials studied, PdSn(50:50)/C showed the best electrochemical and Fuel Cell's results. It is about 33% better than Pd/C. The micrographs obtained by Transmission Electron Microscopy (TEM) revealed some agglomerate regions, but they are consistent with the literature data.

Palavras-Chave: electrocatalysts; ethanol; x-ray diffraction; direct ethanol fuel cells; oxidation; nanomaterials; raman spectroscopy

FONTES, ERIC H.; RAMOS, CARLOS E.D.; NANDENHA, JULIO; PIASENTIN, RICARDO M.; OLIVEIRA NETO, ALMIR; LANDERS, RICHARD. Structural analysis of PdRh/C and PdSn/C and its use as electrocatalysts for ethanol oxidation in alkaline medium. International Journal of Hydrogen Energy, v. 44, n. 2, p. 937-951, 2019. DOI: 10.1016/j.ijhydene.2018.11.049. Disponível em: http://repositorio.ipen.br/handle/123456789/30033. Acesso em: $DATA.

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Abstract: The analysis of the thermoluminiscence (TL) kinetics parameters of SOL-GEL α-Al2O3 with several different concentrations of impurities prepared through the solgel process is reported. A TL glow curve measured at 0.2 K/s after beta irradiation to 0.5 Gy revealed one peak at approximately 447 K. TL spectra were acquired and showed luminescent emission bands around 420 nm and 750 nm. The activation energies, the frequency factors, and the kinetic order involved in the TL emission were evaluated using the maximum peak temperature response, the peak shape of the TL glow curve, the TL glow curve area, and the glow curve fitting methods. The order of kinetics of the peak was evaluated as first order using TM dependence on the radiation dose. The (TM–Tstop) technique was used for determining the number of peaks in the glow curve. The activation energies obtained are in agreement with all the applied methods. The activation energy calculated by various methods varied from 0.885 ± 0.008 eV to 1.05 ± 0.10 eV. The frequency factor determined by all methods was of the order of 109 s−1. The dosimetric peak is affected by thermal quenching. The following thermal quenching parameters were estimated: the activation energy of the thermal quenching W= 1.05 ± 0.15 eV and the constant C = 8.27 × 1010 s−1. The trapping parameters of SOL-GEL α-Al2O3 detectors are reported in the present work for the first time.

Palavras-Chave: sol-gel process; thermoluminescence; samplers; aluminium oxides; crystal structure; activation energy; emission spectra; rpl dosemeters

POLO, IVON O.; JUNOT, DANILO O.; CALDAS, LINDA V.E. SOL-GEL α-Al2O3 samples: analysis of the TL kinetics. Journal of Applied Physics, v. 125, n. 18, p. 185102-1 - 185102-14, 2019. DOI: 10.1063/1.5088139. Disponível em: http://repositorio.ipen.br/handle/123456789/30031. Acesso em: $DATA.

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Abstract: This work focuses on the analysis of the seasonal cycle of temperature and relative humidity (RH) profiles and integrated water vapor (IWV) obtained from microwave radiometer (MWR) measurements over the mid-latitude city of Granada, southern Spain. For completeness the study, the maximum atmospheric boundary layer height (ABLHmax) is also included. To this end, we have firstly characterized the HATPRO-RPG MWR errors using 55 colocated radiosondes (RS) by means of the mean-bias (bias) profile and the standard deviation (SDbias) profile classified under all-weather conditions and cloud-free conditions. This characterization pointed out that temperature from HATPRO-MWR presents a very low bias respects RS mostly below 2.0 km agl, ranging from positive to negative values under all-weather conditions (from 1.7 to −0.4 K with SDbias up to 3.0 K). Under cloud-free conditions, the bias was very similar to that found under allweather conditions (1.8 to −0.4 K) but with smaller SDbias (up to 1.1 K). The same behavior is also seen in this lower part (ground to 2.0 km agl) for RH. Under all-weather conditions, the mean RH bias ranged from 3.0 to −4.0% with SDbias between 10 and 16.3% while under cloud-free conditions the bias ranged from 2.0 to −0.4% with SDbias from 0.5 to 13.3%. Above 2.0 km agl, the SDbias error increases considerably up to 4 km agl (up to −20%), and then decreases slightly above 7.0 km agl (up to−5%). In addition, IWV values from MWR were also compared with the values obtained from the integration of RS profiles, showing a better linear fit under cloudfree conditions (R2=0.96) than under all-weather conditions (R2=0.82). The mean bias under cloud-free conditions was −0.80 kg/m2 while for all-weather conditions it was −1.25 kg/m2. Thus, the SDbiasfor all the statistics (temperature, RH and IWV) of the comparison between MWR and RS presented higher values for allweather conditions than for cloud-free conditions ones. It points out that the presence of clouds is a key factor to take into account when MWR products are used. The second part of this work is devoted to a seasonal variability analysis over five years, leading us to characterize thermodynamically the troposphere over our site. This city atmosphere presents a clear seasonal cycle where temperature, ABLHmax and IWV increase from winter to summer and decrease in autumn, meanwhile RH decreases along the warmer seasons. This city presents cold winters (mean daily maximum temperature: 10.6 ± 1.1 °C) and dry/hot summers (mean daily maximum temperature of 28.8 ± 0.9 °C and mean daily maximum of surface RH up to 55.0 ± 6.0%) at surface (680m asl). Moreover, considering temporal trends, our study pointed out that only temperature and RH showed a linear increase in winters with a mean-rate of (0.5 ± 0.1) °C/year and (3.4 ± 1.7) %/year, respectively, from ground to 2.0 km agl, meanwhile IWV presented a linear increase of 1.0 kg·m−2/year in winters, 0.78 kg·m−2/year in summers and a linear decrease in autumns of −0.75 kg·m−2/year.

Palavras-Chave: microwave radiation; atmospheres; seasonal variations; remote sensing; thermodynamic properties; boundary layers; radiometers

BEDOYA-VELASQUEZ, ANDRES E.; NAVAS-GUZMAN, FRANCISCO; MOREIRA, GREGORI de A.; ROMAN, ROBERTO; CAZORLA, ALBERTO; ORTIZ-AMEZCUA, PABLO; BENAVENT-OLTRA, JOSE A.; ALADOS-ARBOLEDAS, LUCAS; OLMO-REYES, FRANCISCO J.; FOYO-MORENO, INMACULADA; MONTILLA-ROSERO, ELENA; HOYOS, CARLOS D.; GUERRERO-RASCADO, JUAN L. Seasonal analysis of the atmosphere during five years by using microwave radiometry over a mid-latitude site. Atmospheric Research, v. 218, p. 78-89, 2019. DOI: 10.1016/j.atmosres.2018.11.014. Disponível em: http://repositorio.ipen.br/handle/123456789/30029. Acesso em: $DATA.

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Abstract: This paper presents a review in gold nanoparticles focusing on chemical reduction synthesis mechanisms. We hope to aid students and researchers starting in the nanotechnology field by compiling the most used synthesis methods, so they can select the ones that best suit them. The compiled information in this paper approached the following methods: Turkevich Method; Synthesis with NaBH4 with/without citrate; Seeding- Growth; Synthesis by Ascorbic Acid; Green Synthesis; Brust-Schiffrin; and synthesis using other reducing agents. Papers that had clear synthesis information were selected for this work, but that doesn't mean they were synthesis focused. Over 150 papers were analyzed. After compiling the information for these papers, we can conclude that nanoscience is revolutionizing all the areas that are applied to.

Palavras-Chave: gold; nanoparticles; synthesis; chemical reactions; reduction; nanotechnology; citrates; sodium compounds; ascorbic acid; surfactants; borohydrides; bromides; seeds

SOUZA, CARLA D. de; NOGUEIRA, BEATRIZ R.; ROSTELATO, MARIA E.C.M. Review of the methodologies used in the synthesis gold nanoparticles by chemical reduction. Journal of Alloys and Compounds, v. 798, p. 714-740, 2019. DOI: 10.1016/j.jallcom.2019.05.153. Disponível em: http://repositorio.ipen.br/handle/123456789/30027. Acesso em: $DATA.

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Abstract: Objective: To evaluate the radiation dose received by staff in spine surgeries, including those who are not considered occupationally exposed workers. Methods: All spinal surgeries performed in the same department during a period of 12 months were evaluated with regard to the exposure of surgeons, scrub nurses, and auxiliary personnel working in the operating room to radiation from C-arm fluoroscopy. Radiation was measured by 15 film badge dosimeters placed on the professionals’ lapels, gloves, and room standardized sites. The films were analyzed in the dosimetry laboratory by collections per period. Results: During the 12 months, 81 spinal surgeries were performed by the same team, with surgical times ranging from 1 to 6 hours. The total radiation dose ranged from 0.16 mSv to 2.29 mSv depending on the dosimetry site. The most exposed site was the wrist of the main surgeon. Conclusion: The results showed that in the spinal surgeries in our setting, the radiation doses are low and within legal limits. Nevertheless, constant training of professionals is essential for radiation protection of medical staff and patients. Level of evidence I/b, exploratory cohort study.

Palavras-Chave: radiation absorption analysis; radiation doses; fluoroscopy; spinels; surgery

CRISTANTE, ALEXANDRE F.; BARBIERI, FABIO; SILVA, ALMY A.R. da; DELLAMANO, JOSE C. Radiation exposure during spine surgery using C-arm fluoroscopy. Acta Ortopédica Brasileira, v. 27, n. 1, p. 46-49, 2019. DOI: 10.1590/1413-785220192701172722. Disponível em: http://repositorio.ipen.br/handle/123456789/30025. Acesso em: $DATA.

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Abstract: We present the results of methane profiling in the lower troposphere using LILAS Raman lidar from the Lille University observatory platform (France). The lidar is based on a frequency-tripled Nd:YAG laser, and nighttime profiling up to 4000 with 100m height resolution is possible for methane. Agreement between the measured photoncounting rate in the CH4 Raman channel in the free troposphere and numerical simulations for a typical CH4 background mixing ratio (2 ppm) confirms that CH4 Raman scattering is detected. The mixing ratio is calculated from the ratio of methane (395.7 nm) and nitrogen (386.7 nm) Raman backscatters, and within the planetary boundary layer, an increase of the CH4 mixing ratio, up to a factor of 2, is observed. Different possible interfering factors, such as leakage of the elastic signal and aerosol fluorescence, have been taken into consideration. Tests using backscattering from clouds confirmed that the filters in the Raman channel provide sufficient rejection of elastic scattering. The measured methane profiles do not correlate with aerosol backscattering, which corroborates the hypothesis that, in the planetary boundary layer, not aerosol fluorescence but CH4 is observed. However, the fluorescence contribution cannot be completely excluded and, for future measurements, we plan to install an additional control channel close to 393 nm, where no strong Raman lines exist and only fluorescence can be observed.

Palavras-Chave: raman spectroscopy; optical radar; troposphere; methane; feasibility studies

VESELOVSKII, IGOR; GOLOUB, PHILIPPE; HU, QIAOYUN; PODVIN, THIERRY; WHITEMAN, DAVID N.; KORENSKIY, MIKHAEL; LANDULFO, EDUARDO. Profiling of CH4 background mixing ratio in the lower troposphere with Raman lidar: a feasibility experiment. Atmospheric Measurement Techniques, v. 12, n. 1, p. 119-128, 2019. DOI: 10.5194/amt-12-119-2019. Disponível em: http://repositorio.ipen.br/handle/123456789/30023. Acesso em: $DATA.

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Abstract: In conventional gamma-ray spectrometry, the probability of pile-up effects is considered to be proportional to the dead-time, and is usually neglected for low dead-times (below 4-5%). In gamma-gamma coincidence spectrometry, though, while the dead time takes into account only events that are actually digitized, the pile-up effects are proportional to the actual gamma-ray detection rate in each detector, not only to the ones that trigger the coincidence gate. Thus, the pile-up corrections may not be so easy to assess as in single spectrometry systems. In this work, a system composed of two HPGe detectors coupled to a CAEN v1724 digitizer is studied. A 3kBq 60Co source was analyzed, both alone and in the presence of other radioactive sources (137Cs, 133Ba and 152Eu), and the resulting coincidence peak areas were compared to assess the effectiveness of two distinct corrections: a simple normalization by the live time of acquisition and the normalization by the count rate obtained using a pulse generator. The results obtained stress the need to use the pulse generator in this specific setup in order to get accurate results.

Palavras-Chave: corrections; digitizers; data acquisition; dead time; gamma radiation; barium 133; europium 152; cesium 137; cobalt 60; data acquisition; high-purity ge detectors; pulse pileup

ZAHN, GUILHERME S.; RIBEIRO JUNIOR, IBERE S.; GENEZINI, FREDERICO A. Pile-up correction for coincidence counting using a CAEN 1724 digitizer. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-10, 2019. DOI: 10.15392/bjrs.v7i2A.578. Disponível em: http://repositorio.ipen.br/handle/123456789/30021. Acesso em: $DATA.

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Abstract: Background: Cutaneous leishmaniasis (CL) is a parasitic disease caused by the protozoan Leishmania spp. Pentavalent antimonial agents have been used as an effective therapy, despite their side effects and resistant cases. Their pharmacokinetics remain largely unexplored. This study aimed to investigate the pharmacokinetic profile of meglumine antimoniate in a murine model of cutaneous leishmaniasis using a radiotracer approach. Methods: Meglumine antimoniate was neutron-irradiated inside a nuclear reactor and was administered once intraperitoneally to uninfected and L. amazonensis-infected BALB/c mice. Different organs and tissues were collected and the total antimony was measured. Results: Higher antimony levels were found in infected than uninfected footpad (0.29% IA vs. 0.14% IA, p = 0.0057) and maintained the concentration. The animals accumulated and retained antimony in the liver, which cleared slowly. The kidney and intestinal uptake data support the hypothesis that antimony has two elimination pathways, first through renal excretion, followed by biliary excretion. Both processes demonstrated a biphasic elimination profile classified as fast and slow. In the blood, antimony followed a biexponential open model. Infected mice showed a lower maximum concentration (6.2% IA/mL vs. 11.8% IA/mL, p = 0.0001), a 2.5-fold smaller area under the curve, a 2.7-fold reduction in the mean residence time, and a 2.5-fold higher clearance rate when compared to the uninfected mice. Conclusions: neutron-irradiated meglumine antimoniate concentrates in infected footpad, while the infection affects antimony pharmacokinetics.

Palavras-Chave: parasitic diseases; protozoa; antimony; radioisotopes; chemotherapy; bioassay

BORBOREMA, SAMANTA E.T.; OSSO JUNIOR, JOAO A.; ANDRADE JUNIOR, HEITOR F. de; NASCIMENTO, NANCI do. Pharmacokinetics of neutron-irradiated meglumine antimoniate in Leishmania amazonensis-infected BALB/c mice. Journal of Venomous Animals and Toxins including Tropical Diseases, v. 25, p. 1-9, 2019. DOI: 10.1590/1678-9199-JVATITD-1446-18. Disponível em: http://repositorio.ipen.br/handle/123456789/30019. Acesso em: $DATA.

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Abstract: Specimens of the Cichla pinima are of ecological and economic importance in the Amazon region and are a good bioindicator species of Hg bioaccumulation. Adult specimens of Cichla pinima were obtained by fisheries in the Tapajós river region’s impacted gold mining area. Tissues such as muscle, liver, skin, and gill were submitted for total mercury (THg) analysis. For hepatic bioavailability, assays were carried out in the whole liver and in the sub-cellular hepatic fraction. The weight–length relationship showed an equation ofW= 2E− 06L3.3002 (R2 = 0.856) indicating an allometric growth. The mean THg values found in the muscle tissue of 676 ± 258 μg kg−1 were below the maximum limit established for human consumption, but were similar to Cichla fish from other areas impacted by Hg in the Amazon region. The trends of levels in the tissues were as follows: liver>muscle>gonads>skin>gill, with no significant differences between the gills and skin. A significant and positive correlation as rs = 0.65 was obtained between the THg contents in cytosolic fraction and the total hepatic THg (liver homogenate). However, only 7% of the THg were found and were available to the sub-cellular hepatic fraction. This profile can be an indicative of a hepatic cellular transference in fish exposed to high Hg levels in the Amazon region now that low concentrations of Hg have been found in the sub-cellular fraction. However, data of differential THg partition in the subcellular compartments should be considered, since others’ hepatic fractions can act in the Hg linkage into the cell.

Palavras-Chave: fishes; amazon river; brazil; mercury; concentration ratio; environmental impacts

AZEVEDO, JULIANA de S.; HORTELLANI, MARCOS A.; SARKIS, JORGE E. de S. Organotropism of total mercury (THg) in Cichla pinima, ecological aspects and human consumption in fish from Amazon region, Brazil. Environmental Science and Pollution Research, v. 26, p. 21363-21370, 2019. DOI: 10.1007/s11356-019-05303-x. Disponível em: http://repositorio.ipen.br/handle/123456789/30017. Acesso em: $DATA.

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Abstract: This work reported a detailed analysis of the electrochemical impedance spectra obtained for the Mg electrode during immersion in a sodium sulfate solution. A model was proposed which took into account the presence of: (i) a thin oxide film (MgO) which progressively covered the Mg electrode surface, (ii) film-free areas where the Mg dissolution occurs in two consecutive steps, (iii) a thick layer of corrosion products (Mg(OH)2), (iv) an adsorbed intermediate ðMgþ ads Þ which is responsible for the chemical reaction allowing the negative difference effect to be explained. From the impedance data analysis, various parameters were extracted such as the thin oxide film thickness, the resistivity at the metal/oxide film interface and at the oxide film/electrolyte interface, the active surface area as a function of the exposure time to the electrolyte, the thickness of the thick Mg(OH)2 layer and the kinetic constants of the electrochemical reaction.

Palavras-Chave: corrosion; impedance; spectroscopy; electrochemical corrosion; magnesium; tin oxides; adsorption

GOMES, MAURILIO P.; COSTA, ISOLDA; PEBERE, NADINE; ROSSI, JESUALDO L.; TRIBOLLET, BERNARD; VIVIER, VINCENT. On the corrosion mechanism of Mg investigated by electrochemical impedance spectroscopy. Electrochimica Acta, v. 306, p. 61-70, 2019. DOI: 10.1016/j.electacta.2019.03.080. Disponível em: http://repositorio.ipen.br/handle/123456789/30015. Acesso em: $DATA.

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Abstract: Many nuclear research reactors use or are planned with cores containing flat-plate-type fuel elements. One of the problems of this fuel element design is the mechanical stability of the fuel plates. High-velocity coolant flowing through the narrow channels that separate the plates can cause large deflections of these plates leading to local overheating, structural failure or plate collapse. In particular, in real fuel elements and experimental tests, flowinduced deflections at the leading edge and along the length of the plates have been detected. Some authors have indicated that the use of a support comb removes the leading-edge static divergence, but it has been also suggested that, even with the comb, there are significant deflections away from the inlet. In this work, a fluid-structure interaction study is conducted to examine the effectiveness of using an inlet comb on the mechanical stability of fuel plates. The system consists of two fuel plates bounded by three-equal coolant channels. The pressure loadings caused by the fluid flow are calculated using a CFD model and the structural response of the plates and the support comb are determined by means of an FEA model. The two-way fluid-structure interaction method was employed for coupling the fluid and solid solvers. The results presented here show that the static divergence at the inlet end is effectively eliminated with the installation of a support comb. Nevertheless, the main contribution of this work is the detection of deformation of the plates along their length and that it was an increasing function of the fluid velocity in the channels. As a consequence, the flow channels could be constricted or completely closed, thus affecting the safe operation of the nuclear reactor. To the best of our knowledge, this is the first numerical analysis reported in the literature that models the fluid-structure interaction phenomenon of adjacent plates with the support comb located at the midpoint of their inlet end.

Palavras-Chave: fuel plates; fuel elements; critical velocity; fluid-structure interactions; numerical data; nuclear fuels

MANTECON, JAVIER G.; MATTAR NETO, MIGUEL. Numerical analysis on stability of nuclear fuel plates with inlet support comb. Nuclear Engineering and Design, v. 342, p. 240-248, 2019. DOI: 10.1016/j.nucengdes.2018.12.009. Disponível em: http://repositorio.ipen.br/handle/123456789/30013. Acesso em: $DATA.

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Abstract: This work investigates the influence of different nitration protocols of a carbon black, the addition of tungsten carbide (WC), and the presence of iron, in terms of the catalytic activity of electrocatalysts containing Fe-Nx moieties towards the oxygen reduction reaction (ORR) in acidic and alkaline media. The synthesized materials were characterized using X-ray diffraction (XRD), Raman spectroscopy (Raman), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) with a rotating ring-disk electrode (RRDE), in addition to durability tests. In acidic media, the performance of the catalysts varied according to the type of nitration protocol, the presence of iron, and the heat treatment temperature, which is accompanied by variations in the ORR mechanism. In alkaline electrolyte, the electrocatalysts presented higher performances, with only an ~0.04-V difference relative to that of a standard platinum on carbon catalyst. The number of electrons transferred per oxygen molecule, the amounts of hydrogen peroxide generated in the ORR, the effect of catalyst loading, and the presence of iron in the catalysts were investigated with the aim of understanding the ORR mechanism and assisting in the production of high-performance and durable materials. Finally, the two best electrocatalysts were submitted to a standard durability test, which evidenced promising high stability at both pHs.

Palavras-Chave: electrocatalysts; nitration; redox reactions; tungsten carbide; raman spectra; electrochemistry; iron; carbon black; nitrogen

REGO, ULISSES A. do; LOPES, THIAGO; BOTT-NETO, JOSE L.; GOMEZ-MARIN, ANA M.; TANAKA, AURO A.; TICIANELLI, EDSON A. Non-noble Fe-Nx/C electrocatalysts on tungsten carbides/N-doped carbons for the oxygen reduction reaction. Electrocatalysis, v. 10, n. 2, p. 134-148, 2019. DOI: 10.1007/s12678-018-0503-1. Disponível em: http://repositorio.ipen.br/handle/123456789/30011. Acesso em: $DATA.

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Abstract: The characterization of edible tissues of fishes consumed by humans is very important for determination of sev-eral toxic and potentially toxic elements, ensuring the food safety. The Instrumental Neutron Activation Analysis (INAA) comparative method allows the determination of several of these elements, as well as others, for example of nutritional character. This study is part of an International Atomic Energy Agency (IAEA) technical coopera-tion project of Latin America and Caribbean countries to ensure the quality of food and biomonitoring of con-taminants in shellfish and fishes. Ten specimens of 4 of the most consumed fish in São Paulo city: whitemouth croaker (Micropogonias Furnieri), smooth weakfish (Cynoscion learchus), common snook (Centropomus undeci-malis) and Brazilian sardine (Sardinella brasiliensis) were analyzed. Complete procedures for analysis, which includes purchase in the largest warehouse in Latin America, transport to the laboratory, storage, freeze-drying, milling, weighting and others preparations of the subsamples, and the short irradiation parameters for the de-termination of Br, Cl, K, Mg, Mn and Na are reported. Results obtained under the same irradiation conditions for reference materials (oyster and mussel tissues) for macro and microelements are presented and are in agreement with their certificates, which indicate that the performed analyses were appropriate. Regarding to the mass fraction values obtained for the fish samples, they were in agreement with the literature.

Palavras-Chave: neutron activation analysis; fishes; brazil; contamination; gamma spectroscopy; quality assurance; quality management; high-purity ge detectors; radioisotopes; food; quality control

TAPPIZ, B.; MOREIRA, E.G. Neutron activation analysis characterization procedures for fish consumed at São Paulo city. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.710. Disponível em: http://repositorio.ipen.br/handle/123456789/30009. Acesso em: $DATA.

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Abstract: Natural radioactivity is ubiquitous in the environment mainly due to the presence of the nuclides from the ura-nium and thorium series and 40K. Although in the South Hemisphere nuclear tests have been fewer in number than that in the North, artificial radionuclides can also be found spread at ground level. In this study, the activity concentrations of natural nuclides from the uranium and thorium series, 40K and the artificial 137Cs were deter-mined in a sediment core with 42 cm depth collected in the middle of the Salesópolis reservoir, located in the Metropolitan Region of São Paulo city (SPMR). The Usina Parque Rio Tietê reservoir belongs to the Alto do Tietê system for the capture, storage and treatment of water for SPMR. Therefore, the quality of the water and sediments of this dam is of great importance. The activity concentrations were measured by gamma spectrome-try. Samples were measured and saved at regular intervals at a maximum of 160 000 seconds. The gross area were determined for each peak and plotted against time and the counting rate was obtained by the slope of the curve. Background and reference materials were also counted and treated in the same way. Results showed that 226Ra varied from 45 to 116 Bq kg-1; 228Ra, from 80 to 165 Bq kg-1; 40K, from 155 to 1 187 Bq kg-1 and 137Cs varied from 0.3 to 7 Bq kg-1. The methodology applied for determining low levels of 137Cs in sediment proved to be effi-cient and reproducible.

Palavras-Chave: natural radioactivity; water reservoirs; uranium; thorium; potassium 40; cesium 137; sediments; brazil; radioisotopes; gamma spectroscopy; water quality

SILVA, P.S.C.; SEMMLER, R.; ZAHN, G.S.; ROCHA, F.R.; DAMATTO, S.R.; FAVARO, D.I.T. Natural and artificial nuclides in Salesópolis reservoir. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.657. Disponível em: http://repositorio.ipen.br/handle/123456789/30007. Acesso em: $DATA.

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Abstract: A study of the influence of a dosimetric holder and its cover for the irradiation of the dosimeters in the Beta Secondary Standard BSS2 radiation fields is reported. The correction factors for attenuation or scattering were calculated taking into account the BSS2 beta source energy, as well as the detector source distance. The study and the determination of these factors were carried out using the Monte Carlo Method. The results of the correction factors showed that the absorption and scattering of the electrons depend greatly on the energy of beta radionuclides. The determined correction factors are in agreement with the international report ISO 6980.

Palavras-Chave: monte carlo method; radiation sources; attenuation; radiation protection; dosemeters; scattering

POLO, IVON O.; SANTOS, WILLIAM S.; CALDAS, LINDA V.E. Monte Carlo modeling of a holder for irradiation of dosimeters in beta radiation beams. Applied Radiation and Isotopes, v. 143, p. 60-66, 2019. DOI: 10.1016/j.apradiso.2018.10.020. Disponível em: http://repositorio.ipen.br/handle/123456789/30005. Acesso em: $DATA.

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Abstract: This work reports on effect of zinc and milling time on microstructure and Vickers hardness of mechanically alloyed and spark plasma sintered (66,7-x)Ti-xZn-22,2Si-11,1B alloys (at.-%, with x ¼ 2 and 6 at.-%). Ball milling at different times (20, 60, 180 and 300 min) was performed under argon atmosphere in a planetary ball mill from these elemental powder mixtures. Cylinder bodies with 10mm diameter were consolidated by spark plasma sintering (1100 C, 12 min, 20MPa) under argon atmosphere. Asmilled powders and sintered Ti-Zn-Si-B samples were evaluated by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, laser diffraction particle size analysis, and Vickers hardness tests. It was noted a similar behavior during ball milling of Ti-Zn-Si-B powder mixtures. Only the a-Ti and Si peaks were indexed in XRD patterns of Ti-Zn-Si-B powders milled for 300min. Rietveld refining indicated that the amount of amorphous structures has increased during milling up to 300 min, which was more pronounced for the Ti-6Zn-22Si-11B powders. The particle sizes of the Ti-2Zn-22Si-11B and Ti-6Zn-22Si-11B powder mixtures increased during milling from 94 (20 min) to 156 (300min) mm and from 101 (20 min) to 136 (300 min) mm, respectively. Coherently, the average specific surface area of powder particles was continuously reduced during milling. Despite the adopted parameters, the SPS process produced dense Ti-xZn-22Si-11B (x ¼ 2 and 6 at.-%) alloys with 98% from their theoretical specific mass. Regardless of milling time, the Ti6Si2B formation was inhibited in microstructure of the spark plasma sintered Ti-6Zn-22Si-11B alloy previously milled for longer times. EDS analysis indicated that the Ti6Si2B phase dissolved close to 1.8 at.-% Zn. Beside the TiB and Ti5Si3, the Ti2Zn and Ti3Zn (not explored) phases were also found in microstructure of sintered Ti-Zn-Si-B alloys. The Ti-2Zn-22Si-11B alloy presented average Vickers hardness values higher than 1050 HV whereas the Ti-6Zn-22Si-11B alloy varied between 970 and 1036 HV, which could be associated with the Ti6Si2B formation.

Palavras-Chave: zinc; titanium alloys; vickers hardness; plasma; sintering; microstructure; healing; bone mineral density

FERREIRA, NELSON D.; LEAL NETO, RICARDO M.; FILGUEIRA, MARCELLO; FERREIRA, LUCAS M.; ALVES, MANUEL F.R.P.; RAMOS, ERIKA C.T.; NUNES, CARLOS A.; SANTOS, CLAUDINEI dos; RAMOS, ALFEU S. Microstructure and Vickers hardness of mechanically alloyed and spark plasma sintered Ti-2Zn-22Si-11B and Ti-6Zn-22Si-11B alloys. Journal of Alloys and Compounds, v. 794, p. 615-624, 2019. DOI: 10.1016/j.jallcom.2019.04.172. Disponível em: http://repositorio.ipen.br/handle/123456789/30003. Acesso em: $DATA.

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Abstract: The article shows new designed cermets and processes concerning primary to applications as thermal insulation materials with low emissivity. A new projected microstructure was obtained where dense regions (micropellets) rest inside the main porous pellet. The feature resembles a frozen hypercube, therefore such architecture is called hyper-pellet/ cermet. The processing method to obtain the hyper-cermet is based on sequential tape castings and sintering techniques. Ni-zirconia lamellae were prepared by a special mechanochemical process followed by sintering, which remain inside the main pellets as a dense region. The whole pellet is turned to be porous by employing pore-forming additives. All the constituents and porosity shapes are aligned along the disc/ flake planes. Thermal conductivity is estimated for the materials up to 800 °C by a flash diffusivimeter. Ceramographic analyses show graded density regions with directional constituents and pores. Applications of such materials are foreseen as temperature insulation materials and thermal radiation shields.

Palavras-Chave: cermets; ceramics; radiations; shields; thermal insulation; emissivity; heat transfer; thermal conductivity

RESTIVO, THOMAZ A.G.; BECCARI, RAFAEL F.; PADILHA, WELLINGTON R.; DURAZZO, MICHELANGELO; TELLES, VICTOR B.; COLETI, JORGE; YAMAGATA, CHIEKO; SILVA, ANTONIO C. da; SUZUKI, EDUARDO; TENORIO, JORGE A.S.; MELLO-CASTANHO, SONIA R.H. Micrograded ceramic-metal composites. Journal of the European Ceramic Society, v. 39, n. 12, p. 3484-3490, 2019. DOI: 10.1016/j.jeurceramsoc.2019.03.018. Disponível em: http://repositorio.ipen.br/handle/123456789/30001. Acesso em: $DATA.

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Abstract: Elemental mercury is highly toxic and may be absorbed by dental professionals through direct skin contact or inhalation. The use of mercury in dental amalgam has been a concern of the academic community for years, for its incorporation is likely to affect vital organ systems. Several studies have been conducted to address the possible risks of occupational exposure to mercury vapor in dental offices. The present study aimed to present evidences that mercury is assimilated by exposed workers through the determination of urinary mercury (HgU) from dental professionals (n = 91) of public offices in Araguaína (Tocantins, Brazil). This uptake was verified against samples from unexposed individuals (n = 43), which activities are not dentistry related. Cold vapor atomic absorption spectrometry (CV-AAS) technique enabled the subjects’ biological monitoring. Approximately 44.8% (n = 60) of the 134 participants were aged between 21 and 30 years and were at the beginning of their professional lives; 9.7% (13) of the study participants were men and 90.3% (121) were women. Hg concentrations in all samples analyzed were within the maximum biological limit set by the World Health Organization (WHO) (<50 μgHg·L−1). HgU concentrations in dental professionals were within the limits proposed by the Brazilian regulatory standard, Regulatory Norm-7 (RN-7) (≤35 μgHg·g−1 creatinine). Nevertheless, the average concentration of HgU was approximately 8 times higher in the potentially exposed group (5.61 μgHg·g−1 creatinine) than in the unexposed group (0.65 μgHg·g−1 creatinine), highlighting the potential risk of occupational exposure to mercury.

Palavras-Chave: mercury; occupational exposure; dentistry; mercury alloys; monitoring; absorption spectroscopy; validation; brazil

VILLIBOR, FERNANDA F.; GUILHEN, SABINE N.; DANTAS, ELIZABETH S.K.; PIRES, MARIA A.F. Mercury exposure among dental staff in the legal Amazon. Brazilian Journal of Health Review, v. 2, n. 4, p. 2530-2544, 2019. DOI: 10.34119/bjhrv2n4-025. Disponível em: http://repositorio.ipen.br/handle/123456789/29999. Acesso em: $DATA.

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Abstract: Seasoned flour, also known as “farofa”, is a low cost industrialized product easy to prepare, which may be enriched with nutrients in order to improve its nutritional value. Typically, it’s made from maize or yuca tem-pered flour. However, soy seasoned flour (SSF), which is made from okara (inert-flavored-mass obtained as a residue from the soybean extract), is a viable alternative for nutritional enrichment in relation to the previous conventional tempered flour. This work aimed to reuse a by-product of processing of soybean okara to elaborate soy-seasoned flour and to analyze the possible effect of gamma irradiation at doses of 1 and 3 kGy, in the analy-sis of determination of lipid peroxidation. The preparation of SSF containing okara, dehydrated condiments and flavor uplifting proceeded at FATEC Marília. SSF samples were processed at “Centro de Energia Nuclear na Agricultura” (CENA), University of Piracicaba-SP, and irradiated with doses of 1 and 3 kGy in 60Co source. The dose rate was 0.269/h. Analysis were performed to determine the peroxide index of control samples and irra-diated in triplicate at 1, 15, 30 and 45 storage days according to the methodology for oils and fats with modifica-tions. Using this peroxide methodology, it was not detected changes in oxidative quality in the samples, whatever was the storage period. The flour having as a parameter 29.92% of lipids. We conclude that this product have excellent nutritional attributes regards to the conventional flour, though we must apply a different methodology to detect any radiation damage on lipid compounds using doses up to 3kGy.

Palavras-Chave: soybeans; radiation effects; food processing; flour; ionizing radiations; lipids; radiation doses; preservation; dose rates; cobalt 60; oxidation; peroxides

SÁ, A.P.N.; GOES-FAVONI, S.S.P.; GIANNONI, J.A.; ARTHUR, V.; VILLAVICENCIO, A.L.C.H. Irradiation effect on lipid oxidation index on okara-based soybean flour. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-10, 2019. DOI: 10.15392/bjrs.v7i2A.662. Disponível em: http://repositorio.ipen.br/handle/123456789/29997. Acesso em: $DATA.

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Abstract: Biochar (BC) is a carbon-rich product obtained when biomass is thermally decomposed at relatively low temperatures (under 700ºC) and limited supply of oxygen in a process called pyrolysis. Because of its porous structure, charged sur-face and surface functional groups, BC exhibits a great potential as an adsorbent. Its characteristics strongly depend on the feedstock and the pyrolysis conditions. The aim of this study was to evaluate the adsorption potential for the remov-al of uranium, U(VI) from aqueous solutions using BC obtained through slow pyrolysis of the macauba coconut endo-carp. The influence of parameters such as pH, sorbent dose and initial concentration on the adsorption of U(VI) was investigated. The BC obtained at 350 °C (BC350) presented a removal percentage of approx. 80 %, demonstrating its applicability for the treatment of uranium contaminated aqueous solutions.

Palavras-Chave: adsorption; uranium; chars; biological materials; concentration ratio; coconut palms; temperature dependence; waste water; pyrolysis; ph value

GUILHEN, S.N.; COLETI, J.; TENORIO, J.A.S.; FUNGARO, D.A. Influence of adsorption parameters on uranium adsorption capability by biochar derived from macauba coconut residue. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-14, 2019. DOI: 10.15392/bjrs.v7i2A.590. Disponível em: http://repositorio.ipen.br/handle/123456789/29995. Acesso em: $DATA.

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Abstract: Optical waveguide amplifiers have seen a growing interest in the last years due to their applications in telecommunication. This paper reports a notable increase of the relative gain of Yb3þ/Er3þ codoped Bi2O3 eGeO2 waveguides by introducing disorder in the form of silicon nanostructure as scattering centers. A photoluminescence enhancement of about 10 times for the 520 nm and 1530 nm emission bands is observed in the waveguides when the silicon nanostructures are introduced. Increase of the Yb3þ/Er3þ effective absorption, due to the scattering provided by the silicon nanostructures, and decrease of [Biþ], caused by the introduction of silicon, are proposed as likely causes for the luminescence and gain enhancement. The pedestal waveguides were fabricated by RF-sputtering followed by optical lithography and reactive ion etching. RF-sputtering of silicon together with Yb/Er and Bi2O3eGeO2 glass, followed by heat treatment, produced Yb3þ/Er3þ codoped Bi2O3eGeO2 waveguides with silicon nanostructures of size 25e30 nm. The resulting relative gain reached 5.5 dB/cm at 1542 nm representing an enhancement of 50% with respect to waveguides without silicon nanostructures. This strategy of introducing appropriate disorder may open an avenue for designing and manufacture of novel photonic devices in this emerging field of integrated optics.

Palavras-Chave: ytterbium; erbium; doped materials; nanostructures; optical properties; sputtering; amplifiers; scanning electron microscopy

WETTER, NIKLAUS U.; SILVA, DIEGO S. da; KASSAB, LUCIANA R.P.; JIMENEZ-VILLAR, ERNESTO. Improving performance in ytterbium-erbium doped waveguide amplifiers through scattering by large silicon nanostructures. Journal of Alloys and Compounds, v. 794, p. 120-126, 2019. DOI: 10.1016/j.jallcom.2019.04.141. Disponível em: http://repositorio.ipen.br/handle/123456789/29993. Acesso em: $DATA.

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Abstract: An instant non-scanning tomography system is being developed at the IPEN. This type of tomography system, due to its configurations, provides a low spatial resolution; however, it presents a high temporal resolution as an advantage. In this sense, it has high applicability in industrial processes involving dynamic multiphase processes, like distillation columns. Thereby, to obtain the best conditions of image acquisition, this tomography system comprising different collimators was simulated with Monte Carlo using the MCNP4C.The image quality was evaluated with Matlab® 2013b analyzing the contrast to noise ratio (CNR), root mean square ratio (RMSE), signal to noise ratio (SNR) and the spatial resolution by the Modulation Transfer Function (MTF(f)), to identify which collimator fits better to the tomography in development. It was simulated three situations; (i) with no collimator; (ii) ø 25x 50 mm2 cylindrical collimator with a septum of ø5.0 x 50 mm2; (iii) ø25 x 50 mm2 cylindrical collimator with a slit septum of 24 x 5.0 x 50 mm3. RMSE values for no collimator presented better results. CNR showed that no collimator and slit collimator reaches the same CNR values, but no collimator decreases more than the slit collimator as the number of iteration rises. The hole collimator reaches a higher CNR value, however decreases more than the others. The spatial resolution with no collimator and slit collimator were around 31.9 mm, and for the hole collimator was around 20 mm.

Palavras-Chave: collimators; tomography; computerized tomography; computerized simulation; monte carlo method; quality assurance; quality management; image processing; nai detectors; signal-to-noise ratio; radiation detectors; radiation detectors; industrial plants; brazilian cnen

VELO, A.F.; ALVAREZ, A.G.; HAMADA, M.M.; MESQUITA, C.H. Image quality analysis of an industrial instant non-scanning tomography system with different collimators. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-14, 2019. DOI: 10.15392/bjrs.v7i2A.561. Disponível em: http://repositorio.ipen.br/handle/123456789/29991. Acesso em: $DATA.

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Abstract: In this work the pathway of the chemical product and the kinetics parameters were evaluated in a laboratory plant settled, using 0.4 GBq (10 mL) of 67Ga citrate as radiotracer and 18 NaI(Tl) radiation detectors. The AnaComp program was used to estimate the kinetic para ameters of the acetone production. The yield of the acetone production was estimated by the percentage ratio between the areas under the curve (AUC) of the curve profiles of the final product compartment divided by the concentration found inside the chemical reactor whose result was 87% yield during the first 30 minutes of reaction.

Palavras-Chave: gallium 67; citrates; multi-channel analyzers; acetone; nai detectors; tracer techniques; calibration; radioactivity; kinetics

MESQUITA, C.H. de; CALVO, W.A.P.; AOKI, P.E.; SILVA, V.C. da; HARAGUCHI, M.I.; VELO, A.F.; ALVAREZ, A.G.; HAMADA, M.M. Gallium-67 citrate used as a tracer of acetone production routes. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.562. Disponível em: http://repositorio.ipen.br/handle/123456789/29989. Acesso em: $DATA.

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Abstract: Food irradiation is approved for use in more than 60 countries for applications and purposes in a wide variety of foods, being an effective and safe method for preservation and long-term storage. 2- Alkylcyclobutanones (2-ACBs) are the only known radiolytic products generated from foods that contain fatty acids (Triglycerides) when irradiated. The acids analyzed in this study are palmitic and stearic, which when irradiated form 2-Dodecylcyclobutanones (2-dDCB) and 2-Tetradecylcyclobutanone (2-tDCB). Part of the 2-ACBs ingested is excreted through feces and part is deposited in adipose tissues. In vitro studies so far have been only in colon cells. The work used a human hepatoma cell line (HepG2) since the accumulation of fat in this organ is quite common. Micronucleus test was selected to evaluate possible genotoxic effects of 2-dDCB and 2-tDCB compounds when exposed to high concentrations (447, 1422 and 2235 μM) for 4 and 24 hours. Tests were performed in quadriplicates using flow cytometric analysis. None detectable genotoxic damage was observed after 4 hours of exposure to the compounds, and cytotoxic effects were only significant at the highest concentration (2235 μM) of 2-dDCB. After 24 hours of exposure, slight genotoxic damage was observed at all concentrations evaluated, and cytotoxic effects were only present when exposed to compound 2-tDCB. Although there is a genotoxic and cytotoxic effect in some of the situations tested, the two compounds predominantly induced proliferation reduction effects of this hepatic tumor cell line.

Palavras-Chave: food processing; irradiation; hexadecanoic acid; cell flow systems; dodecyl radicals; hepatomas; in vitro; octadecanoic acid; radiation effects; toxicity; carcinomas

BARBEZAN, ANGELICA B.; SANTOS, CARLA J.B.; CARVALHO, LUMA R.; VIEIRA, DANIEL P.; SANTELLI, GLAUCIA M.M.; VILLAVICENCIO, ANNA L.C.H. Flow cytometry based micronucleus assay for evaluation of genotoxic potential of 2-ACBs in hepatic cells HepG2. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-24, 2019. DOI: 10.15392/bjrs.v7i2A.684. Disponível em: http://repositorio.ipen.br/handle/123456789/29987. Acesso em: $DATA.

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Abstract: The response of the commercial XRA-24 PIN photodiode (5.76 mm2 active area) for clinical electron beam dosimetry covering the range of 8-12 MeV was investigated. Within this energy range, the charge generated in the diode’s sensitive volume is linearly dependent on the absorbed dose up to 320 cGy. However, charge sensitivity coefficients evidenced that the dose response of the diode is slightly dependent on the electron beam energy. Indeed, the diode’s energy dependence was within 8.5% for 8-12 MeV electron beams. On the other hand, it was also observed an excellent repeatability of these results with a variation coefficient (VC) lower than 0.4%, which is within the 1% tolerance limit recommended by the AAPM TG-62. Furthermore, the agreement between the percentage depth dose profiles (PDD) gathered with the diode and the ionization chamber allowed achieving the electron beam quality within 1% of that obtained with the ionization chamber. Based on these results, the photodiode XRA-24 can be a reliable and inexpensive alternative for electron beams dosimetry.

Palavras-Chave: dosimetry; electron beams; feasibility studies; ionization chambers; photodiodes; depth dose distributions; energy dependence; mev range 01-10; silicon diodes

NASCIMENTO, C.R.; ASFORA, V.K.; BARROS, V.S.M.; GONCALVES, J.A.C.; ANDRADE, L.F.R.; KHOURY, H.J.; BUENO, C.C. Feasibility studies of using thin entrance window photodiodes for clinical electron beam dosimetry. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-9, 2019. DOI: 10.15392/bjrs.v7i2A.577. Disponível em: http://repositorio.ipen.br/handle/123456789/29985. Acesso em: $DATA.

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Abstract: The feed pulverized coal used at Figueira thermoelectric power plant (FTPP) presents a significant amount of uranium concentration and the potential radiological impact pathways into the surrounding environments should be monitored frequently. Neutron activation analysis was used to determine 238U and 232Th, and gamma-ray spectrometry was used to determine 226Ra, 228Ra, 210Pb and 40K contents present in coal, different types of coal ashes, their synthesized zeolites and two different soil samples collected in the vicinity of FTPP as well as, radiological indices to determine possible health effects due to radiation exposition. The natural radionuclide concentrations in pulverized coal were 216 Bq kg–1 for 238U, 180 Bq kg–1 for 226Ra, 27 Bq kg–1 for 228Ra, 28 Bq kg–1 for 232Th and 192 Bq kg–1 for 40K. The ashes fraction presented concentrations ranging from 683.5 to 1479 Bq kg–1 for 238U, from 484 to 1086 Bq kg–1 for 226Ra, from 291 to 1891 Bq kg–1 for 210Pb, from 67 to 111 Bq kg–1for 228Ra, from 80 to 87 Bq kg–1 for 232Th and from 489 to 718 Bq kg–1 for 40K. Similar ranges were observed for the different zeolitic products. The activity concentration of 238U was higher than worldwide average concentration for all samples. The concentration of the uranium series found in the ashes was lower than the values observed in similar studies carried out 10 years ago and under the limit adopted by the Brazilian guideline (CNEN-NN-4.01). The radiological indices indicated that the environmental disposal of fly ashes may represent a risk for public health, therefore, the resulting data can be used for systematic studies on radiological implication due to the release of TENORM caused by coal-fired power plant.

Palavras-Chave: soils; coal; fly ash; zeolites; concentration ratio; thermoelectricity; natural radioactivity; baghouses; contamination; gamma spectroscopy; neutron activation analysis

FUNGARO, D.A.; SILVA, P.S.C.; CAMPELLO, F.A.; MIRANDA, C.S.; IZIDORO, J.C. Evaluation of radionuclide contamination of soil, coal ash and zeolitic materials from Figueira Thermoelectric Power Plant. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-18, 2019. DOI: 10.15392/bjrs.v7i2A.606. Disponível em: http://repositorio.ipen.br/handle/123456789/29983. Acesso em: $DATA.

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Abstract: The greatest impact of the tomography technology currently occurs in medicine. The success is due to the fact that human body presents standardized dimensions with well-established composition. These conditions are not found in industrial objects. In industry, there is a great deal of interest in using the tomography in order to know the inner part of (i) manufactured industrial objects or (ii) the machines and their means of production. In these cases, the purpose of the tomography is: (a) to control the quality of the final product and (b) to optimize the production, contributing to the pilot phase of the projects and analyzing the quality of the means of production. This scan system is a non-destructive, efficient and fast method for providing sec-tional images of industrial objects and it is able to show the dynamic processes and the dispersion of the ma-terials structures within these objects. In this context, it is important that the reconstructed image may present a great spatial resolution with a satisfactory temporal resolution. Thus, the algorithm to reconstruct the imag-es has to meet these requirements. This work consists in the analysis of three different iterative algorithm methods, namely the Maximum Likelihood Estimation Method (MLEM), the Maximum Likelihood Trans-mitted Method (MLTR) and the Simultaneous Iterative Reconstruction Method (SIRT. The analyses in-volved the measurement of the contrast to noise ratio (CNR), the root mean square error (RMSE) and the Modulation Transfer Function (MTF),in order to know which algorithm fits the conditions to optimize the system better. The algorithms and the image quality analyses were performed by Matlab® 2013b.

Palavras-Chave: tomography; iterative methods; computerized tomography; algorithms; quality control; diagnostic techniques; images; image scanners

VELO, A.F.; ALVAREZ, A.G.; HAMADA, M.M.; MESQUITA, C.H. Evaluation of iterative algorithms for tomography image reconstruction. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-16, 2019. DOI: 10.15392/bjrs.v7i2A.660. Disponível em: http://repositorio.ipen.br/handle/123456789/29981. Acesso em: $DATA.

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Abstract: Textile industry has an expressive scenario in the world economy and Brazil is the 5th in the textile production. By 2015, Brazilian textile production represented US $ 39.3 billion, accounting for more than 1.8 million tons of fabric. The effluents from textile industry are highlighted by quantity of wastewater discharged and variety of substances (dyes, bleaching agents, surfactants, salts, acids, among others). Such compounds often prove to be toxic to aquatic biota. This present study aims to assess toxicity of whole effluents, before and after irradiation (by electron beam accelerator, EBI). In addition, the reduction of the effluent color after irradiation is also very important. Daphnia similis and Vibrio fischeri were the biological systems applied for toxicity evaluations. Previous results demonstrated the surfactant as the main toxic compound, in the untreated and irradiated forms, EC 50 = 0.44 ppm ± 0.02 (untreated); EC 50 = 0.46 % ± 0.07 (irradiated). The irradiation was effective for reducing color of the effluent, starting from 0.5 kGy. EB irradiation may be proposed as an alternative treatment for the final effluent from textile processing, mainly for reuse purposes.

Palavras-Chave: textile industry; color; chemical effluents; toxicity; ethoxy radicals; removal; surfactants; waste processing; waste water; water treatment; irradiation; electron beams; bacteria; crustaceans

BORRELY, S.I.; SILVA, L.G.A.; DEL SOLE, S.V.; GARCIA, V.S.G.; BOIANI, N.F.; ROSA, J.M. Electron beam irradiation of textile effluents and non-ionic ethoxylated surfactant for toxicity and color removal. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-10, 2019. DOI: 10.15392/bjrs.v7i2A.702. Disponível em: http://repositorio.ipen.br/handle/123456789/29979. Acesso em: $DATA.

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Abstract: Background – Carbapenem-resistant bacterial infections are a critical problem in veterinary medicine with limited treatment options. Objective – To describe effective probiotic and photodynamic therapy of a dog with gut colonization and ear infection caused by a hospital-associated lineage of carbapenemase (VIM-2)-producing Pseudomonas aeruginosa. Animals – A 5-year-old Lhasa apso dog presented with otitis externa. Methods and materials – Unilateral otitis externa caused by carbapenem-resistant P. aeruginosa was treated with antimicrobial photodynamic therapy (aPDT) using methylene blue as photosensitizer [wavelength 660 nm, fluence 140 J/cm2, 8 J and 80 s per point (six equidistant points), 100 mW, spot size 0.028 cm2 and fluence rate 3.5 W/cm2]. The isolated bacterial strain also was tested for susceptibility to in vitro aPDT where the survival fraction was quantified by colony forming unit counts after exposure to increasing light doses. For decolonization, probiotic supplements were orally administered (once daily) for 14 days. Effectiveness of probiotics and photodynamic therapy was evaluated by clinical and microbiological culture assays. Results – Complete resolution of clinical signs was achieved by Day 7 after aPDT. Samples collected immediately and after seven and 14 days following aPDT were negative for VIM-2-producing P. aeruginosa. Oral and rectal swabs collected on days 7, 14 and 21 after probiotic therapy, confirmed effective gastrointestinal decolonization. Conclusions and clinical importance – Combined use of aPDT and probiotics could be a promising therapeutic strategy for treatment of superficial infections produced by carbapenem-resistant bacteria, while avoiding recurrent infection due to intestinal bacterial carriage of these multidrug-resistant pathogens.

Palavras-Chave: dogs; veterinary medicine; domestic animals; microorganisms; therapy; methylene blue; antimicrobial agents; bacterial diseases; photosensitivity

SELLERA, FABIO P.; FERNANDES, MIRIAM R.; SABINO, CAETANO P.; FREITAS, LAURA M. de; SILVA, LUCIANO C.B.A. da; POGLIANI, FABIO C.; RIBEIRO, MARTHA S.; HAMBLIN, MICHAEL R.; LINCOPAN, NILTON. Effective treatment and decolonization of a dog infected with carbapenemase (VIM-2)-producing Pseudomonas aeruginosa using probiotic and photodynamic therapies. Veterinary Dermatology, v. 30, n. 2, p. 170-e52, 2019. DOI: 10.1111/vde.12714. Disponível em: http://repositorio.ipen.br/handle/123456789/29977. Acesso em: $DATA.

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

Palavras-Chave: dosimetry; skin absorption; external irradiation; therapy; radiotherapy; thermoluminescence; electron beam injection; lymphomas

ALMEIDA, S.B.; VILLANI, D.; SAKURABA, R.K.; REZENDE, A.C.P.; CAMPOS, L.L. Dosimetric evaluation and comparation of TL responses of LiF:Mg,Ti and μLiF:Mg,Ti in the clinical electron beams dosimetry applied to total skin irradiation (TSEB) treatments. Radiation Measurements, v. 125, p. 15-18, 2019. DOI: 10.1016/j.radmeas.2019.03.007. Disponível em: http://repositorio.ipen.br/handle/123456789/29975. Acesso em: $DATA.

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

Palavras-Chave: electron beams; accelerators; accelerator facilities; automation; control systems; sweep circuits; brazilian cnen

SOMESSARI, S.L.; MOURA, J.A.; CALVO, W.A.P. Development of an automated system for the operation of an electron beam accelerator. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-12, 2019. DOI: 10.15392/bjrs.v7i2A.593. Disponível em: http://repositorio.ipen.br/handle/123456789/29973. Acesso em: $DATA.

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

Palavras-Chave: uranium; thorium; sediments; estuaries; rivers; brazil; spectrophotometry; water pollution monitors

TEIXEIRA, LUIZ F.L.; MAZZILLI, BARBARA P. Determination of uranium and thorium in sediments from Cananéia‑Iguape system, Brazil. Journal of Radioanalytical and Nuclear Chemistry, v. 320, n. 3, p. 551-560, 2019. DOI: 10.1007/s10967-019-06528-3. Disponível em: http://repositorio.ipen.br/handle/123456789/29971. Acesso em: $DATA.

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

Palavras-Chave: dosemeters; thermoluminescent dosemeters; monte carlo method; neutron activation analysis; radiations

CAVALIERI, TASSIO A.; SIQUEIRA, PAULO T.D.; SHORTO, JULIAN M.B.; GENEZINI, FREDERICO A.; YORIYAZ, HELIO. Design, fabrication and modeling of an AmBe neutron irradiator for TLD screening for neutron dose measurement in mixed radiation fields. Applied Radiation and Isotopes, v. 150, p. 31-38, 2019. DOI: 10.1016/j.apradiso.2019.05.009. Disponível em: http://repositorio.ipen.br/handle/123456789/29969. Acesso em: $DATA.

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

Palavras-Chave: aluminium alloys; corrosion; anodization; tartaric acid; sulfuric acid; cerium ions; sol-gel process; electrochemistry

TERADA, M.; QUEIROZ, F.M.; AGUIAR, D.B.S.; AYUSSO, V.H.; COSTENARO, H.; OLIVIER, M.G.; MELO, H.G. de; COSTA, I. Corrosion resistance of tartaric-sulfuric acid anodized AA2024-T3 sealed with Ce and protected with hybrid sol–gel coating. Surface & Coatings Technology, v. 372, p. 422-426, 2019. DOI: 10.1016/j.surfcoat.2019.05.028. Disponível em: http://repositorio.ipen.br/handle/123456789/29967. Acesso em: $DATA.

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

Palavras-Chave: nuts; selenium; zinc; barium; manganese; concentration ratio; ecological concentration; neutron activation analysis; quality control; brazil

ARMELIN, M.J.A.; MAIHARA, V.A.; COZZOLINO, S.M.F.; SILVA, P.S.C.; SAIKI, M. Concentrations of Se, Ba, Zn and Mn in Brazil nuts. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-10, 2019. DOI: 10.15392/bjrs.v7i2A.701. Disponível em: http://repositorio.ipen.br/handle/123456789/29965. Acesso em: $DATA.

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

Palavras-Chave: kaolinite; bentonite; cobalt ions; calcination; activated carbon; adsorption; interfering elements; mixtures; neutron activation analysis; ph value; surface area; waste water

SOUZA, ELIEL S.; SILVA, PAULO S.C. Co adsorption in kaolinite. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-15, 2019. DOI: 10.15392/bjrs.v7i2A.658. Disponível em: http://repositorio.ipen.br/handle/123456789/29963. Acesso em: $DATA.

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

Palavras-Chave: scintillations; gamma radiation; crystal growth; neutron activation analysis; lead ions; barium 122; cesium 137; cobalt 60; sodium 22; cesium iodides; annealing; bridgman method; doped materials; gamma spectroscopy; luminescence

PEREIRA, MARIA da C.C.; FILHO, TUFIC M.; BERRETTA, JOSE R.; TOMAZ, LUCAS F.; PINTO, MARLENE C. Characteristics of Pb2+ doped CsI matrix under gamma and neutron excitations. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-13, 2019. DOI: 10.15392/bjrs.v7i2A.595. Disponível em: http://repositorio.ipen.br/handle/123456789/29961. Acesso em: $DATA.

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Abstract: Pre-sintering for removal of lubricants is one of the most important steps in processing of powder metallurgy materials to achieve corrosion resistance. This is often the most neglected step in the sintering process. Incomplete removal of these organic compounds may result in sensitization of sintered parts. The aim of this study is to investigate the effect of lubricant removal process on the corrosion resistance of sintered AISI 304 L stainless steel filters. Pre-sintering was carried out at 450° C and sintering at 1150° C. As lubricant, 1% wax was used. The corrosion resistance of sintered samples was evaluated by polarization and tests, optical and scanning electron microscopy. The results showed that lubricant removal was not complete and during sintering sensitization of the stainless steel occurred decreasing the localized corrosion resistance of the stainless steel.

Palavras-Chave: corrosion; corrosion resistance; stainless steels; sintering; filters; polarization; optical microscopy; scanning electron microscopy; lubricants

BARBOSA, L.P.; CORREA, O.V.; KARSOKAS FILHO, N.; COSTA, I. Corrosion characterization of AISI 304 stainless steel filter. Materials Science Forum, v. 930, p. 489-494, 2018. DOI: 10.4028/www.scientific.net/MSF.930.489. Disponível em: http://repositorio.ipen.br/handle/123456789/29959. Acesso em: $DATA.

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

Palavras-Chave: strontium 90; water; water pollution; physical radiation effects; accuracy

NISTI, M.B.; SAUEIA, C.H.R.; CASTILHO, B.; MAZZILLI, B.P. Assessment of Sr-90 in water samples: precision and accuracy. Brazilian Journal of Radiation Sciences, v. 7, n. 2A, p. 1-12, 2019. DOI: 10.15392/bjrs.v7i2A.559. Disponível em: http://repositorio.ipen.br/handle/123456789/29955. Acesso em: $DATA.

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Abstract: Computed tomography (CT) is a method of imaging used for the diagnosis and treatment of diseases. Different from the conventional diagnostic radiology equipment, where the test for the determination of the half value layer (HVL) is recommended, in CT equipment due to its geometry, the determination of the HVL is a difficult task and is usually only provided by the manufacturer. The effective energy of a beam is determined by definition, by means of HVL determination. When HVL values are not easily determined, as in the case of CT, it is possible to evaluate the effective energy of the beam through a system consisting of the use of different energy dependent dosimeters, where the ratio between the calibration curve responses in energy can provide the effective energy of the beam (Tandem system). The system used in this work for the evaluation of HVL in computed tomography is composed of groups formed by an ionization chamber of the pencil-type and cylindrical absorber layers of aluminum and Polymethyl methacrylate (PMMA).

Palavras-Chave: tomography; computerized tomography; radiations; radiation chemistry; ionization chambers; pmma

FONTES, LADYJANE P.; CORREA, EDUARDO L.; POTIENS, MARIA da P.A. Application of a Tandem system for HVL evaluation in computed tomography. Radiation Physics and Chemistry, v. 155, p. 62-64, 2019. DOI: 10.1016/j.radphyschem.2018.08.023. Disponível em: http://repositorio.ipen.br/handle/123456789/29953. Acesso em: $DATA.

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Abstract: Aim: Dietary fats absorbed in the intestine are transported in the circulation as chylomicrons and remnants that have atherogenic potential. Although postprandial lipidemia is increased in older subjects, the specific chylomicron metabolism has not been explored in older subjects nor compared to young subjects, which is the focus of this study. Methods: After a 12 h fast, artificially-made emulsions similar to lymph chylomicrons and doubly labeled with radioactive cholesteryl esters and triglycerides were intravenously injected in 23 older (66±4 years) and 20 young (24±3 years) subjects. Sequential blood samples were collected to determine fractional clearance rates (FCR, in min-1) by compartmental analysis. Results: Older subjects had higher LDL-cholesterol (p<0.001) and triglycerides (p<0.0001) than young subjects; HDL-cholesterol presented no difference. The emulsion cholesteryl-ester FCR was lower in older subjects compared to the young (p¼0.0001). The emulsion triglyceride FCR did not differ in the two groups. Tested in vitro, however, the lipolysis of the emulsion triglycerides was less intense in the older than in the young subjects. Conclusions: As delayed removal of remnants, indicated by the pronouncedly smaller cholesteryl ester FCR, is related to the presence of cardiovascular diseases, this can be a risk factor which could accelerate atherogenic complications occurring in aged subjects.

Palavras-Chave: lipids; chylomicrons; blood plasma; clearance; blood plasma; cardiovascular diseases

TAVONI, T.M.; VINAGRE, C.G.; FREITAS, F.R.; MESQUITA, C.H.; VINAGRE, J.C.; MARIANI, A.C.; KALIL-FILHO, R.; MARANHAO, R.C. Plasma clearance of chylomicron remnants is delayed in aged subjects: a study with artificial emulsions. Atherosclerosis, v. 275, p. e157-e157, 2018. DOI: 10.1016/j.atherosclerosis.2018.06.468. Disponível em: http://repositorio.ipen.br/handle/123456789/29949. Acesso em: $DATA.

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Abstract: Cancer is responsible for more than 12% of all causes of death in the world, with an annual death rate of more than 7 million people. In this scenario melanoma is one of the most aggressive ones with serious limitation in early detection and therapy. In this direction we developed, characterized and tested in vivo a new drug delivery system based on magnetic core-mesoporous silica nanoparticle that has been doped with dacarbazine and labelled with technetium 99 m to be used as nano-imaging agent (nanoradiopharmaceutical) for early and differential diagnosis and melanoma by single photon emission computed tomography. The results demonstrated the ability of the magnetic core-mesoporous silica to be efficiently (>98%) doped with dacarbazine and also efficiently labelled with 99mTc (technetium 99 m) (>99%). The in vivo test, using inducted mice with melanoma, demonstrated the EPR effect of the magnetic core-mesoporous silica nanoparticles doped with dacarbazine and labelled with technetium 99 metastable when injected intratumorally and the possibility to be used as systemic injection too. In both cases, magnetic core-mesoporous silica nanoparticles doped with dacarbazine and labelled with technetium 99 metastable showed to be a reliable and efficient nano-imaging agent for melanoma.

Palavras-Chave: melanomas; neoplasms; silica; nanoparticles; magnetic properties; magnetic cores; drug delivery; therapy; images; technetium 99

PORTILHO, FILIPE L.; HELAL-NETO, EDWARD; CABEZAS, SANTIAGO S.; PINTO, SUYENE R.; SANTOS, SOFIA N. dos; POZZO, LORENA; SANCENON, FELIX; MARTINEZ-MANEZ, RAMON; SANTOS-OLIVEIRA, RALPH. Magnetic core mesoporous silica nanoparticles doped with dacarbazine and labelled with 99mTc for early and differential detection of metastatic melanoma by single photon emission computed tomography. Artificial Cells, Nanomedicine, and Biotechnology, v. 46, p. S1080–S1087, 2018. S1, DOI: 10.1080/21691401.2018.1443941. Disponível em: http://repositorio.ipen.br/handle/123456789/29947. Acesso em: $DATA.

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