Jorge Javier Acosta Manosalvas

This study presents the conceptual design and numerical dynamic analysis of a bowl-type vibratory finishing machine through CAD development and simulation. The methodology integrates a literature review of process and design variables, definition of operating requirements, selection of the abrasive system, mechanical sizing of critical components, and formulation of a numerical model for modal and transient dynamic analysis. The proposed machine was configured as a bowl-type system with eccentric-mass excitation, spring suspension, and a compact support structure. The specific contribution of this work lies in integrating, within a single design-oriented framework, the definition of the main machine variables, the mechanical sizing of critical components, and the modal and transient dynamic analysis of a proposed architecture prior to prototyping. The modal assessment retained ten modes, with the closest relevant frequencies remaining separated from the nominal 25 Hz excitation within the adopted screening framework. For the refined transient case, synchronized X(t) and Y(t) histories permit direct reconstruction of the bowl-edge X–Y trajectory. Over the selected late-time interval of 0.6–1.0 s, the directional half-range displacements were 1.119 mm in X and 1.095 mm in Y, while least-squares harmonic amplitudes at 25 Hz were 1.047 and 1.046 mm, respectively. These values provide directional structural-response metrics for numerical screening and a reference for subsequent experimental radial-amplitude comparison. A targeted spring-stress sensitivity study yielded local von Mises maxima of 504.84, 2111.2, and 2978.2 MPa across progressively refined global and local adaptive configurations; the large changes in magnitude and hotspot location indicate pronounced sensitivity of the spring-end peak to local adaptive refinement. Accordingly, this quantity is treated as a model-dependent local hotspot. The abrasive-loaded configuration is used as a first-order structural-inertial representation of operating mass for machine-level screening.

Plastic waste management remains a significant environmental and economic challenge in developing countries, where insufficient recovery infrastructure hinders the transition toward sustainability. This study evaluates the industrialization of post-consumer plastics in Ecuador under the 2020 Law on Reuse and Reduction of Single-Use Plastics. Official 2024 datasets were quantitatively analyzed to calculate national indicators of per capita plastic waste generation, estimated annual plastic waste generation, and the plastic recovery index. The results show that Ecuador recovered and industrialized 106,145 tons of post-consumer plastics in 2024, achieving a recovery rate of 16%, which positions the country among the top performers in Latin America; however, direct comparisons with global recycling estimates should be interpreted cautiously. Per capita plastic waste generation reached 37.13 kg cap⁻¹ yr⁻¹, yet approximately 664,633 t yr⁻¹ of plastic waste are generated annually, representing a substantial potential risk of environmental leakage if not adequately managed, recovered, or valorized. Although Ecuador demonstrates measurable progress toward implementing the circular economy, persistent gaps in data standardization, source segregation of waste, and policy enforcement limit further advancement. Strengthening institutional coordination, market incentives, and public participation is essential to accelerate a more sustainable and circular plastics system.

This study analyzes the technical and economic feasibility of hybrid photovoltaic-wind systems for residential self-consumption in the city of Manta, Ecuador. A single-family home with a monthly demand of 200 kWh was evaluated using climate data from PVGIS (solar irradiance) and NASA POWER (wind speed), validated with the Ecuador Wind Atlas. It was found that the solar resource has an average of 4.29 peak solar hours (HSP) and peaks of 600 W/m², while wind resources are moderate (4.0-4.5 m/s at 30 m, density 70-100 W/m²). A hybrid system was designed to cover 70% of the demand with solar energy and 30% with wind energy, complemented by a 200 Ah gel battery and a 3 kW hybrid inverter. The estimated overall efficiency is 90%, considering losses. From a financial analysis, the system has a Levelized Cost of Energy of $0.0494/kWh, a positive Net Present Value of $54.2, and an Internal Rate of Return of 6.20%, demonstrating profitability over 25 years. Compared to internal combustion engines, the hybrid obtains a higher multi-criteria score (0.59 vs. 0.41) due to its lower environmental impact and operating costs, confirming the viability of the system. El presente estudio analiza la viabilidad técnica y económica de sistemas híbridos fotovoltaico-eólicos para el autoconsumo residencial en la ciudad de Manta, Ecuador. En el que se evaluó una vivienda unifamiliar con demanda mensual de 200 kWh, utilizando datos climáticos de PVGIS (irradiancia solar) y NASA POWER (velocidad del viento), validados con el Atlas Eólico del Ecuador se tuvo que el recurso solar presenta un promedio de 4.29 horas solares pico (HSP) y picos de 600 W/m², mientras que el eólico es moderado (4.0-4.5 m/s a 30 m, densidad 70-100 W/m²). Se dimensionó un sistema híbrido que cubre el 70% de la demanda con energía solar y el 30% con eólica, complementado por batería de gel de 200 Ah e inversor híbrido de 3 kW. La eficiencia global estimada es del 90% considerando pérdidas. Desde el análisis financiero, el sistema presenta un Costo Nivelado de Energía de 0.0494 USD/kWh, un Valor Actual Neto positivo de 54.2 USD y una Tasa Interna de Retorno del 6.20%, evidenciando rentabilidad a 25 años. Comparado con motores de combustión interna, el híbrido obtiene mayor puntuación multicriterio (0.59 vs. 0.41) por menor impacto ambiental y costos operativos, confirmando la viabilidad del sistema.

El estudio aborda el modelado matemático de la difusión atómica del carbono en acero ASTM A36 mediante la ecuación de Arrhenius y el método de mínimos cuadrados. Se analiza la relación exponencial entre la temperatura y el coeficiente de difusión, linealizando la ecuación para obtener parámetros fundamentales como el prefactor de difusión y la energía de activación . A través de datos experimentales, se emplea un ajuste de regresión lineal para determinar los coeficientes óptimos, minimizando el error cuadrático entre los valores observados y los predichos. Se obtuvieron los valores y , con un error estándar de , lo que valida la precisión del modelo. Los resultados permiten predecir la variación del coeficiente de difusión en función de la temperatura, con aplicaciones en procesos industriales como cementación, tratamientos térmicos y optimización de aleaciones. La metodología empleada demuestra la eficacia de los métodos numéricos en ingeniería de materiales para mejorar el rendimiento estructural del acero bajo condiciones térmicas variables. Este estudio destaca la importancia del análisis computacional y la modelización matemática en la caracterización de materiales, optimizando el diseño de procesos industriales y mejorando la predictibilidad de propiedades mecánicas en aceros estructurales.