Escuela Tecnológica Instituto Técnico Central

Laser guide stars (LGSs) have been deployed for the last 20-30 years in ground-based astronomical telescopes to overcome the limited sky coverage of classical adaptive optics (AO) systems. Unfortunately, slow altitude drifts of the sodium layer compromise focus measurements, generating the so-called slow focus error, and, consequently, a natural guide star (NGS) is needed to compensate that error. The Keck I telescope AO system uses a 20x20 Shack-Hartmann (SH) wavefront sensor (WFS) for slow focus tracking (with a 5x5 mode used on fainter stars). This approach is far from optimal due to limited sky coverage, since the available NGSs are usually very faint. Our goal is to develop a different technique for slow focus tracking and make it fully operational using focal plane wavefront sensing (FPWFS), which can significantly increase sky coverage and allow slow focus tracking at higher frequencies, reducing the lag error. The Keck I near-infrared (NIR) tip-tilt sensor, known as TRICK, is used to obtain the focal plane images without any hardware modifications being necessary. We develop, characterize, and compare three different FPWFS algorithms, namely Gerchberg-Saxton (GS), linearized focal plane technique (LiFT), and Gaussian fit (Gf). These algorithms are studied for the specific purpose of slow focus sensing in the NIR (H and K bands) using numerical simulations and data collected at Keck in 2025 (bench and on-sky). The three algorithms were studied and characterized against different criteria such as linearity, computational costs, and resistance to low signal-to-noise ratio and/or residuals. From the results obtained, the main candidate for an on-sky deployment was GS, for which the main deciding factor was its higher stability and robustness under the presence of residuals. For that reason, on-sky tests in closed loop were made with GS. On-sky tests showed promising results, with GS successfully compensating for purposely introduced focus errors, even under the presence of high turbulence conditions. These tests represent an important step toward the full operationalization of this tool, expected in the coming months. This work can also be extrapolated to other existing 8-10 m class telescopes, or even future 30-40 m class telescopes, where the use of FPWFS can significantly improve sky coverage and reduce the lag error.

Anais do IV Congresso Brasileiro da Sociedade Brasileira de Auditoria Médica - SBAM, sob o tema "Auditoria Médica em transformação: os desafios da equidade com qualidade", realizado de 14 a 16 de agosto de 2025 - Salvador/BA Comissão Científica Dra. Goldete Priszkulnik - CRM SP 41402 Dr. Jayme Malek - CRM SP 55578 Dr. Marcos Santos - CRM SP 94.143 Dra. Martha Oliveira - CRM RJ 52 0069396-0 Dr. Sérgio Dias - CRM SP 113170 Dr. Stephen Stefani - CRM RS 20675 Dr. Vanderlei Soares Moya - CRM SP 4548 Sr. Wilson Folador - CRF SP 10497

This work proposes the methodological basis in the development of a robust power system planning model for capital and intermediate cities using machine learning and computational intelligence techniques. The model, following the methodological basis, seeks to optimize the distribution of energy resources through the analysis of key variables, such as energy demand, generation capacity, use of renewable sources, operating costs and physical distribution infrastructure. The integration of artificial intelligence techniques (and availability of data) allows capturing complex patterns in the operation of the electric system, improving demand prediction and generation dispatch optimization. To this end, a data set is implemented that includes historical information on energy consumption, meteorological variables and characteristics of the electrical infrastructure.

Additive manufacturing via selective laser sintering (SLS) enables the rapid production of geometrically complex polyamide 12 (PA12) components. However, conventional pointwise analysis techniques often overlook the full depth of continuous experimental datasets, thus limiting the interpretation of structure–function relationships that are essential to high-performance design. This study employs functional data analysis (FDA) to elucidate the microstructural, chemical, thermal, and mechanical behaviours of SLS-fabricated PA12, focusing on the effects of build orientation (horizontal, transverse, vertical) and wall thickness (2.0–3.0 mm). The samples were produced via a commercial SLS platform and characterised via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and tensile testing. The FDA was applied to raw, normalised, and first derivative datasets via Python’s Scikit-FDA package, increasing the sensitivity to latent material variations. The findings demonstrate that the build orientation has a marked influence on the crystallinity and mechanical performance: horizontal builds yield narrower gamma-phase XRD peaks, greater structural order, and enhanced tensile properties, whereas vertical builds exhibit broader peak dispersion and greater thermal sensitivity. The wall thickness effects were minor, with only isolated flux-related anomalies. The FTIR spectra confirmed the consistent chemical stability across all the conditions. The FDA successfully identified subtle transitions and anisotropies that eluded traditional methods, underscoring its methodological strength for advanced polymer characterisation. These insights offer practical guidance for refining SLS process parameters and improving predictive design strategies in polymer-based additive manufacturing.

Este trabajo realiza un análisis comparativo de la Zona Afectada por el Calor (ZAC) en acero inoxidable AISI 304 en las posiciones 1G y 3G, utilizando procedimientos de soldadura GTAW manual y automático. El objetivo es determinar cómo varía la ZAC en función de parámetros como espesor de la placa, intensidad, materiales de aporte y velocidad de soldadura, con el fin de optimizar las condiciones para minimizar el tamaño de la ZAC. La metodología incluye una revisión de las propiedades, clasificación y tratamientos térmicos del acero inoxidable, seguida de un análisis experimental comparando probetas con diferentes composiciones de carbono y condiciones de soldadura. Los resultados indican que un mayor contenido de carbono incrementa la extensión de la ZAC, aunque en aceros de bajo carbono la influencia es menor. Además, la dirección del flujo de calor y la velocidad de soldadura afectan significativamente el tamaño de la ZAC; velocidades menores aumentan la extensión, mientras que en espesores mayores la diferencia es menos notable. Esta investigación compara soldaduras GTAW manuales y automáticas en acero inoxidable AISI 304. Analiza la ZA), evaluando cómo el enfriamiento, amperaje y la composición del material influyen en la microestructura y la calidad de la unión soldada.

Abstract This paper analyses the slamming and green water loads on a cruise ship in extreme seas. The experimental measurements on the motions and vertical bending moments from model tests in regular waves will be compared and analysed by comparing them to numerical models, along with the uncertainty analysis. The occurrence and magnitude of the slamming and green water loads in extreme head seas are discussed. The characteristics of the cruise ship’s slamming and green water phenomenon in irregular head seas are identified using the statistical analysis of the measurements from the model tests.

The switched reluctance motor (SRM) has attracted attention in recent decades, due to its robustness, low manufacturing cost, and other performance characteristics. Thanks to the accepted and widely used mathematical model of this motor, model-based controllers, whose main foundation is the precise knowledge/identification of the motor parameters, are frequently reported in the literature and required in the industry. This article proposes a parametric identification for switching reluctance motors under an algebraic approach. The identification is based on the unsaturated model of the motor whose electrical parameters depend on the angular position. This work proposes an adaptation of the classic identification method defined in the spatial and temporal domains, due to the angular dependence on the electrical parameters and the temporal dependence on the mechanic parameters. In addition, the proposed identification strategy is simulated and experimentally validated in a DSP-based test bench. Reduced identification times, low error rates, and non-dependence of tuning parameters were obtained.

El Régimen Simplificado para Emprendedores y Negocios Populares (RIMPE) fue implementado en Ecuador como un sistema tributario que reemplaza al Régimen Impositivo Simplificado Ecuatoriano (RISE). Su propósito es regular la tributación de emprendedores y negocios populares, diferenciando las obligaciones fiscales según los ingresos anuales. Los emprendedores con ingresos de hasta $3,000,000 deben emitir comprobantes tributarios y cumplir con retenciones de IVA, mientras que los negocios populares con ingresos menores a $20,000 solo emiten notas de venta.El estudio analizó la percepción de los contribuyentes sobre el RIMPE a través de encuestas aplicadas a 143 personas. Los resultados revelan un desconocimiento significativo de la normativa y sus implicaciones, lo que ha generado dificultades en el cumplimiento tributario. Aunque el régimen facilita la formalización de pequeños negocios, la falta de estrategias de comunicación y capacitación ha afectado su implementación.En términos económicos, la pandemia de COVID-19 impulsó la necesidad de alternativas laborales, incrementando la cantidad de emprendimientos. Sin embargo, el sistema RIMPE presenta desafíos en la educación tributaria, lo que se refleja en niveles de incumplimiento. El Servicio de Rentas Internas (SRI) debe fortalecer su estrategia de difusión para garantizar el éxito del régimen.