Examinando por Autor "Galleguillos Silva, Renato Bruno"

Mostrando 1 - 4 de 4
  • Miniatura
    Ítem
    Feasibility of using ultrasound for drug delivery through micellar systems
    (Institute of Electrical and Electronics Engineers (IEEE), 2025-04-02) Marambio, E.; Velásquez, P.; Cepeda-Plaza, M.; Galleguillos Silva, Renato Bruno
    A study of micellar structures subjected to continuous high-intensity ultrasonic perturbation was carried out. The micelles were characterized by high-speed absorption spectrophotometry and the use of fluorophores, such as Rhodamine 123, as a spectroscopic indicator of the micellar kinetic process. It was found that above the critical micellar concentration, the absorbance peak of the fluorophore experiences a 14 nm red shift. Preliminary experiments indicate a reversal of this shift under certain ultrasonic conditions. In subsequent experiments, no effect of high intensity ultrasonic radiation on the micellar systems studied was observed. A dependence of the spectroscopic response of Rh123 on temperature is found, which can be confused with the effect of micelle breaking in solutions. The study presented considers the use of Quillaja Saponaria Molina and Triton X-100 as a surfactant, but it is extensible to other micellar systems.
  • Miniatura
    Ítem
    Limitations of transfer learning for chilean cherry tree health monitoring: when lab results do not translate to the orchard
    (MDPI, 2025-08-13) Hidalgo, Mauricio; Yanine, Fernando; Galleguillos Silva, Renato Bruno; Lagos, Miguel; Kumar Sahoo, Sarat; Paredes, Rodrigo
    Chile, which accounts for 27% of global cherry exports (USD 2.26 billion annually), faces a critical industry challenge in crop health monitoring. While automated sensors monitor environmental variables, phytosanitary diagnosis still relies on manual visual inspection, leading to detection errors and delays. Given this reality and the growing use of AI models in agriculture, our study quantifies the theory–practice gap through comparative evaluation of three transfer learning architectures (namely, VGG16, ResNet50, and EfficientNetB0) for automated disease identification in cherry leaves under both controlled and real-world orchard conditions. Our analysis reveals that excellent laboratory performance does not guarantee operational effectiveness: while two of the three models exceeded 97% controlled validation accuracy, their field performance degraded significantly, reaching only 52% in the best-case scenario (ResNet50). These findings identify a major risk in agricultural transfer learning applications: strong laboratory performance does not ensure real-world effectiveness, creating unwarranted confidence in model performance under real conditions that may compromise crop health management.
  • Miniatura
    Ítem
    Phase-controlled array of ultrasonic transducers for active focusing of waves in air. Applied to foam abatement
    (AMA Science, 2025-09-21) Galleguillos Silva, Renato Bruno; Leon-Montalva, Camila; Cancino-Jaque, Eduardo; Meneses-Diaz, Josue; Vargas-Hernandez, Yolanda; Gaete-Garreton, Luis
    This work presents the development and experimental validation of an annular array of 56 ultrasonic transducers operating at 25 kHz for contactless industrial foam abatement. Through phase control algorithms, the system achieves acoustic focusing in air, generating pressure levels exceeding 150 dB SPL at the focal point. Experimental results demonstrate successful foam disruption capabilities, and the scalability was also validated through numerical simulations in COMSOL Multiphysics and laboratory testing.
  • Miniatura
    Ítem
    The La Silla Schmidt Southern Survey
    (IOPS Publishing, 2025-09-29) Miller, Adam A.; Galleguillos Silva, Renato Bruno; Abrams, Natasha S.; Aldering, Greg; Anand, Shreya; Angus, Charlotte R.; Arcavi, Iair; Baltay, Charles; Bauer, Franz E.; Brethauer, Daniel; Bloom, Joshua S.; Et. al.
    We present the La Silla Schmidt Southern Survey (LS4), a new wide-field, time-domain survey to be conducted with the 1 m ESO Schmidt telescope. The 268 megapixel LS4 camera mosaics 32 2k × 4k fully depleted CCDs, providing a ∼20 deg2 field of view with 1″ pixel−1 resolution. The LS4 camera will have excellent performance at longer wavelengths: in a standard 45 s exposure the expected 5σ limiting magnitudes in g, i, z are ∼21.5, ∼20.9, and ∼20.3 mag (AB), respectively. The telescope design requires a novel filter holder that fixes different bandpasses over each quadrant of the detector. Two quadrants will have i band, while the other two will be g and z band with color information obtained by dithering targets across the different quadrants. The majority (90%) of the observing time will be used to conduct a public survey that monitors the extragalactic sky at both moderate (3 days) and high (1 day) cadence, as well as focused observations within the Galactic plane and bulge. Alerts from the public survey will be broadcast to the community via established alert brokers. LS4 will run concurrently with the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST). The combination of LS4+LSST will enable detailed holistic monitoring of many nearby transients: high-cadence LS4 observations will resolve the initial rise and peak of the light curve while less-frequent but deeper observations by LSST will characterize the years before and after explosion. Here, we summarize the primary science objectives of LS4 including microlensing events in the Galaxy, extragalactic transients powered by massive black holes or stellar explosions, the search for electromagnetic counterparts to multi-messenger events, and supernova cosmology.