Submissões Recentes
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Towards integrated photonics
2026 - FERNANDES, THIAGO V.; WETTER, NIKLAUS U.; ROSSI, WAGNER de; KASSAB, LUCIANA R. P.
This review focuses on the fabrication and characterization of optical waveguides inscribed in GeO2–PbO glasses using femtosecond (fs) laser irradiation. Fs laser writing offers key advantages, such as three-dimensional structuring, high precision, and minimal thermal effects to the surrounding material, enabling the production of complex photonic devices within transparent substrates. The discussion covers different cases, each from a distinct sample and reported in separate works: a straight waveguide doped with Yb3+/Er3+, operating as an optical amplifier in the third telecommunications window, straight waveguides doped with Nd3+, with and without Ag nanoparticles and the role of the plasmonic effects on the optical properties at 1064 nm. The results of S-bend and Y-shaped configurations containing Ag nanoparticles are also reviewed due to their relevance for resonant ring and beam splitters, respectively. The role of larger radius is discussed as well as the best Y configuration with respect to the opening angle and separation between the arms. The quality factor (M2) of the proposed architecture is used to evaluate the symmetry between the x and y axes that is relevant to indicate comparable light guidance. The review highlights different configurations as well as their optical properties and the potential applications for integrated photonics.
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Methodology for the simultaneous determination of the parameters associated with the k0 method of neutron activation analysis and experimental determination of the k0 and Q0 parameters for the 158Gd(n, γ )159Gd reaction
2026 - RIBEIRO, RAFAEL V.; MORALLES, MAURICIO; DIAS, MAURO da S.
A nonlinear adjustment framework for the calculation of k`0`-NAA parameters is presented, integrating covariance analysis with the Levenberg–Marquardt optimization algorithm. This approach enables the simultaneous adjustment of multiple parameters, explicitly incorporating their uncertainties and correlations within a unified fitting procedure. Experimental validation was performed using data from irradiations conducted in 2010, 2015, and 2023, resulting in new values of k`0` and Q`0` for several radionuclides. In particular, the adjustment framework enabled the determination of k`0` values for radionuclides and energies previously absent from the reference database. The results were compared with reference data, demonstrating improved reliability and precision in neutron activation analysis. Furthermore, the framework presented here enables the inclusion of different combinations of targets, energies, and irradiation dates in a single adjustment, providing greater flexibility for future applications.
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Hierarchical porosity and electrolyte compatibility in carbon-based supercapacitors
2026 - JARA, FERNANDO G. B.; LEMUS, JORGE D. B.; EMBS, JAN P.; BORDALLO, HELOISA N.; FARIA, RUBENS N.
Supercapacitors are pivotal for high-power energy storage, yet their energy density is governed by the complex interplay between electrode porosity and electrolyte properties. This study reveals how hierarchical porosity dictates the electrochemical performance of carbon-based electrodes—activated carbon from coconut shell (ACMag), commercial activated carbon (ACNag), and reduced graphene oxide (rGOag)—in aqueous (KOH) and deep eutectic solvent (ChClEG) electrolytes. We demonstrate that ACNag, with its hierarchical slit-shaped pores, delivers superior and stable performance (34F/g, 15.6 Ω cm2 in ChClEG). Conversely, ACMag's “ink-bottle” pores cause ion-trapping and higher resistance, while rGOag exhibits extreme electrolyte dependence, excelling in KOH (68 F/g) but failing in viscous ChClEG (8 F/g) due to inadequate porosity. By integrating electrochemical, structural (BET, SEM), and chemical (TG-FTIR-MS) analyses, we establish that optimal capacitance arises from a synergy of electric double-layer formation and surface-mediated pseudocapacitance. Quasi-elastic neutron scattering further shows efficient charge storage occurs via rapid ion diffusion or localized, surface-confined processes. Our findings prove that tailoring hierarchical slit-pores is paramount for balancing ion confinement and accessibility, providing a critical design principle for advanced supercapacitors in renewable energy and high-power applications.
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Desenvolvimento de um procedimento operacional padrão para radioterapia de mama esquerda com técnica de Inspiração profunda com suspensão da respiração
2025 - VARGAS, FRANCIELE C. de
A radioterapia desempenha um papel fundamental no tratamento do câncer de mama, sendo essencial o planejamento preciso da dose de radiação administrada ao paciente. Em tratamentos de câncer de mama esquerda existe um risco maior de exposição cardíaca. A técnica de Inspiração Profunda com Suspensão da Respiração (DIBH) é usada para mitigar a dose de radiação que chega ao coração. Nesse contexto, o objetivo do estudo foi a elaboração de um Procedimento Operacional Padrão (POP) para a radioterapia da mama esquerda utilizando a técnica DIBH, com foco na padronização do processo, na segurança do paciente e na reprodutibilidade do tratamento. O desenvolvimento do POP ocorreu a partir da observação participante da rotina clínica de um serviço de radioterapia, baseado em recomendações internacionais e nos princípios de documentação da gestão da qualidade nacionais. O documento descreve as etapas de seleção de pacientes, simulação, planejamento e tratamento, incluindo checklists operacionais para auxiliar a equipe técnica. Foi estruturado um plano de monitoramento da implantação do POP, contemplando indicadores de adesão e desempenho, com o intuito de garantir sua aplicação consistente e sustentável na prática clínica. A experiência obtida durante a validação do protocolo demonstrou viabilidade de aplicação na rotina clínica, existindo potencial para se tornar um modelo de referência para outros serviços de radioterapia no país.