Communities in PRCR
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- Colecciones de la Albizu University
- Colecciones digitales de Atenas College
- Colecciones de los Centros Sor Isolina Ferré
- Materiales utilizados para la certificación.
Recent Submissions
Evaluación de la Estabilidad, Movilidad y Seguridad de los Peatones en Condiciones de Inundación por Tsunami en Puerto Rico
(Polytechnic University of Puerto Rico, 2025-09-11) Rivera De León, Rosangelie; Pacheco Crosetti, Gustavo E.; Bravo Pérez, Ricardo J.
Este studio evalúa la estabilidad y movilidad de peatones en inundaciones por tsunami. Se analizó el impacto de la profundidad y la velocidad del agua (Fase1) y el esfuerzo físico durante caminatas con espirómetro (Fase2). Los resultados destacan la importancia de la condicionamiento físico, el uso de calzado adecuado, y que la inestabilidad puede producirse con bajos niveles de agua, aun cuando la velocidad del flujo es moderada.
Relationship between Oxygen Consumption vs Plantar Pressure during Uphill Walking and Running
(Polytechnic University of Puerto Rico, 2025-09-11) Ríos Falconi, Jaxiel; Bravo Pérez, Ricardo J.
Inclined walking and running are widely used in athletic training and rehabilitation, yet their combined effects on oxygen consumption (VO₂) and plantar pressure are not fully quantified. Uphill running (4.2 mph) at a 10% slope can reduce vertical loading rate by about 59% compared to level running (7.5 mph) at the same metabolic demand, suggesting potential benefits for reducing impact forces but with higher energy cost. Understanding this trade-off is essential for designing effective training, injury prevention, and rehabilitation programs. This study examines VO₂ and plantar pressure changes across two speeds (3.0 mph, 6.0 mph) and two inclines (0%, 10%). VO₂ was measured using the VO₂ Master analyzer, and plantar pressure with the Tekscan system. Five trials per condition were conducted in a single-subject design. Results showed a VO₂ increase of approximately 73% for walking and 33% for running when moving from 0% to 10% slope, accompanied by corresponding rises in energy cost. Plantar pressure shifted toward the forefoot at 10% incline, while 0% slope maintained a more even distribution. These findings provide relevant data to support performance optimization and rehabilitation strategies.
Nanodiamond Electrodes for Hydrogen Production by Blectrolysis
(Polytechnic University of Puerto Rico, 2025-09-11) Ríos Ortiz, Danliz; Rijo, Enmanuel; Vélez, Ángel
Hydrogen production by water electrolysis is limited by the efficiency of current catalytic materials and the overall process cost. High overpotentials and expensive catalysts raise energy use and capital expenditures, constraining scale-up. Nanodiamond composite electrodes for the hydrogen evolution reaction were developed using two routes: a muffle furnace method and a bell jar chemical reactor. Formulations incorporated nanodiamond powder into a composite matrix with aluminum titanate, lithium chloride, boron, tantalum, and graphene, then were pressed into cylindrical pellets. Structural integrity and catalytic activity were tested in alkaline media prior to electrolysis. Volumetric gas collection was used to quantify hydrogen generation rates and benchmark against graphite and Pt controls. This study offers insights into the use of nanomaterials for hydrogen evolution, showing that nanodiamond electrodes exhibit strong catalytic response at low overpotential.
Tissue preservation using simulated seawater and a low percentage of formaldehyde
(Polytechnic University of Puerto Rico, 2025-09-11) Cortés Galindo, Diana M.; Fernández Lafuente, Diego J.; Pérez Magin, Irela; Rondón Contreras, Jairo J.
Formalin at 10% is the most widely used fixative solution for specimen preservation, but it poses risks of respiratory irritation and long-term effects with increased exposure (IARC, 2006). To identify safer, effective alternatives, pig kidneys were preserved for two months in solutions with 2%, 4%, or 10% formalin with 35% salt, and compared with a 10% formalin control. Dielectric
spectroscopy measured real permittivity (ε′) and impedance (|Z|) as markers of cell membrane and tissue preservation. According to the data, 4% formalin + 35% salt exceeded all other solutions at preservative efficiency, including the 10% formalin control. This study offers evidence of an alternative that is safer to handle with better preservation indicators.
3-D Printed Structural Elements And Their Modeling For Aerospace Usage
(Polytechnic University of Puerto Rico, 2025-09-11) Toro Cruz, Claudia S.; Pertierra García, José R.
This research aims to analyze how of the commonly used 3D printing filaments provided by the MakerSpace Lab to students, who partake in aerospace competitions, when varying infill density and printing orientation, and compared to traditionally used materials like wood, perform when subjected to tensile tests. After undergoing the tests, the specimens made from PLA, PETG, and Nylon of 50% and 20% infill densities and printed in both flat and side orientations showed that PLA of 50% infill density had the highest yield among the filaments. Filaments surpassed the Young’s modulus of Basswood but not Balsawood. Out of all the filaments, Nylon proved to be the most elastic.