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Artigo IPEN-doc 31185 Morphology, roughness, and surface loss of sound enamel submitted to different acid etching agents and different durations of application
2025 - LANDMAYER, KARIN; PASTORI, ISADORA C.; ORDÓÑEZ-AGUILERA, JUAN F.; IATAROLA, BRUNA de O.; ZEZELL, DENISE M.; FRANCISCONI-DOS-RIOS, LUCIANA F.
Objective: Knowledge about the effects of different phosphoric acids can help clinicians choose the appropriate acid etchant, preserving dental structure without compromising bond strength. This study aimed to analyze the morphology, surface loss, and roughness of different acid etching agents, especially a self-limiting phosphoric acid, at different time intervals. Material and Methods: Bovine enamel specimens were allocated into experimental groups (n = 5). The surfaces were treated with acid etchant (UE: UltraEtch; C37: Condac37; PE37: Power Etching 37%; DGC: Dental Gel Conditioner; SE: Scotchbond Etchant) for 15, 30, 60, 90, and 120 s. Surface loss and roughness were evaluated with an optical profilometer, and morphological analyses was performed by Scanning Electron Microscopy. Data were statistically analyzed (α=0.05). Results: The surface loss increased for all acids over time, except for UE. Up to 60 s, none of the acids promoted different surface loss. For 90 s, UE showed the smallest loss, and SE exhibited the greatest loss; for 120 s, UE had the smallest loss, while DGC and SE had the highest. The roughness increased for all acids over time, including UE, except for 90 s. For 90 s, DGC promoted the highest surface roughness, while UE, PE37, and SE showed the smallest. Compared to the control, all acids showed significant differences in structural loss and roughness. Finally, the type 2 etching pattern predominated. Conclusion: UltraEtch exhibited a self-limiting etching behavior, even though it causes an increase in surface roughness, it does not promote a significantly increasing surface loss over time.
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Resumo IPEN-doc 31183 Estudo da resistência à corrosão do aço DP600 e da liga AA5052 soldados por FSW
2025 - IAZIGI, GIOVANNI B. C.; MORAIS, NATHANAEL; PEREIRA, BRUNO N.; ARAUJO, JOÃO V. de S.; COSTA, ISOLDA
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Artigo IPEN-doc 31181 Levantamento de doses de radiação ocupacional em exames radiográficos dos boletos e falanges distais de equinos
2025 - GOULART, MAURICIO E.; POTIENS, MARIA da P.A.
Veterinary medicine has increasingly used X-rays for the diagnosis of various diseases, especially osteoarticular diseases of the fetlocks and distal phalanges. These usually require additional radiographic exposures, resulting in significant radiation doses, which pose a risk to occupational health. This study evaluated radiation doses from primary and scattered radiation, with an emphasis on the ambient dose equivalent (H*(10)) and the personal dose equivalent. It used an X-ray machine typical of veterinary practices, an ionisation chamber, a ring-shaped thermoluminescent dosimeter, and an equine anatomical specimen. Cassettes measuring 18x24 and 35x43 cm were used. The X-ray beam collimations varied in dimensions of 18x24, 24x30, 30x40 and 35x43 cm, in addition to mAs at 5, 2.5 and 1.6. The kVp was kept constant at 70. A higher risk was demonstrated in the D45°L-PaMO oblique radiographic projection. Doses of 0.01882 mSv/exposure were measured in the hand of the IOE carrying the cassette and 0.00026 mSv/exposure for the IOE carrying the X-ray machine, resulting in that to reach the annual investigation level of 150 mSv, it would be necessary to participate in approximately 110 radiographic examinations (patients/month or ± 3 to 4 patients/day) and to reach the monthly investigation level of 20 mSv, approximately 1,063 doses or an average of 5 patients per day would be necessary. The benefit of collimation comparing H*(10) at 70 kVp and 1.6 mAs was demonstrated with collimation 35x43 cm: 0.001013 mSv and 18×24 cm: 0.000223 mSv. The dose is drastically reduced by decreasing the mAs. The dose ratio between the 5 mAs and 1.6 mAs techniques is approximately 5/1.6 ≈ 3.125.
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Artigo IPEN-doc 31180 Evaluation of the Uncertainty in the Measurement of Nanoparticle Size and Concentration by Single Particle Inductively Coupled Plasma Mass Spectrometry Technique
2025 - GERALDES, ADRIANA N.; HORTELLANI, MARCOS A.; ROSTELATO, MARIA E.C.M.; SARKIS, JORGE E.S.
Single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is a powerful technique that enables the simultaneous measurement of nanoparticle size and the quantification of metal-containing nanoparticles at real concentrations. These measurements are critical for understanding the potential uses of nanoparticles in various fields. However, sp-ICP-MS is not yet considered a mature methodology. Standardization is necessary, particularly in assessing the reliability of size distribution measurements. This study aims to standardize sp-ICP-MS by assessing the reliability of size distribution measurements for polyvinylpyrrolidone-coated silver nanoparticles and quantifying the input quantities contributing to uncertainties. The uncertainties in calibration, repeatability, and trueness were evaluated based on the thresholds defined by International Organization for Standardization (ISO) standards. Calibration uncertainty was found to be 8.1%, while repeatability was 0.04%, both within the stipulated range of less than 10%. The expanded uncertainty was calculated to be 17%, with a 95% coverage probability for the reference material. Limits of detection (LOD) and quantification (LOQ) for dissolved concentration, particles per mL, and size were determined to be 0.37 μg L–1, 97.5 particles mL–1, and 24.6 nm, respectively. These results demonstrate that the reliability and repeatability of sp-ICP-MS meet ISO-defined thresholds, suggesting that with further standardization, sp-ICP-MS could become a reliable methodology for nanoparticle analysis.