The operation of various types of turbomachines is importantly affected by sediment erosion. Francis turbines used for power generation typically suffer said effects due to the fact that they are used in sediment-laden rivers and are usually operated disregarding the long-term effect of the erosion on turbine performance. This investigation seeks to study the erosion rate for the main components of the turbines located at San Francisco hydropower plant in Pastaza, Ecuador. A sediment characterization study was performed in order to determine the properties of the particles present in Pastaza River and accurately predict their effect on the turbine flow passages. A numerical approach combining liquid–solid two-phase flow simulation and an erosion model was used to analyze the erosion rates at different operating conditions and determine wear patterns in the components. As expected, the results indicated that an increase in the erosion rate was obtained for higher intake flows. However, a dramatic increase in the erosion rate was observed when the turbine was operated at near-full-load conditions, specifically when guide vane opening exceeded a 90% aperture.

This study investigates how three technical factors—steering wheel tilt, torque, and cabin vibration frequency—affect driver posture. Heavy-truck drivers often suffer from musculoskeletal disorders (MSDs), mainly due to poor cabin ergonomics and prolonged postures during work. In countries like Ecuador, making major structural changes to cabin design is not feasible. These factors were identified through video analysis and surveys from drivers at two Ecuadorian trucking companies. An experimental system was developed using a simplified cabin to control these variables, while posture and muscle activity were recorded in 16 participants using motion capture, inertial sensors, and electromyography (EMG) on the upper trapezius, middle trapezius, triceps brachii, quadriceps muscle, and gastrocnemius muscle. The test protocol simulated key truck-driving tasks. Data were analyzed using ANOVA (${\displaystyle p<0.05}$), with technical factors and mass index as independent variables, and posture metrics as dependent variables. Results showed that head mass index significantly affected head abduction–adduction (${\displaystyle -}$8.12 to ${\displaystyle -}$2.18°), and spine mass index influenced spine flexion–extension (${\displaystyle -}$0.38 to 6.99°). Among technical factors, steering wheel tilt impacted trunk flexion–extension (${\displaystyle -}$13.56 to 16.99°) and arm rotation (${\displaystyle -}$31.1 to 19.7°). Steering wheel torque affected arm rotation (${\displaystyle -}$30.49 to ${\displaystyle -}$6.77°), while vibration frequency influenced forearm flexion–extension (3.76 to 16.51°). EMG signals showed little variation between muscles, likely due to the protocol’s short duration. These findings offer quantitative support for improving cabin ergonomics in low-resource settings through targeted, cost-effective design changes.

This article presents a novel methodology conducted under controlled laboratory conditions to assess the dynamic behavior of the components of railway tracks by applying an unbalanced mass excitation force. The methodology for obtaining accurate measurements, which uses different excitation parameters, is based on an unbalanced mass device, and from these data, the transmissibility of the mass-elastomer system is estimated. For assessment of the dynamic behavior, different sine sweep rate excitations, the unbalanced mass, and background noise are considered. The experimental measurements of transmissibility with a shaker and an unbalanced mass device are performed to validate the methodology. For this, frequency-by-frequency transmissibility measurements and the swept sine were performed by the shaker, with a sine sweep from 1 to 51 Hz, using the unbalanced mass device with different sine sweep rates and unbalanced mass. The results obtained allow comparison of the transmissibility by excitation at specific frequencies and the sine sweep to validate the excitation parameters of the unbalanced mass device. Thus, a transmissibility estimation error with the sweep rate, the unbalanced mass, and the background noise is developed. By using the proposed methodology, it is possible to lower the error of the estimated transmissibility of the system with background noise.

A dynamic neck model is proposed for functional assessment or ergonomic studies using data obtained from conventional biomechanical tools such as video photogrammetry and force platforms. The head and neck inertial parameters are obtained through regression equations and refined through a calibration process to improve accuracy. Head movement is recorded through video photogrammetry, where marker coordinates are used to calculate finite displacements, linear and angular velocities, and accelerations. An inverse dynamics approach is used to estimate the forces and moments at the C7 vertebral level and the generated muscle power. The model was validated through an experimental study with 30 participants, where its estimates were compared to the measurements obtained from a force platform. The comparison aimed to assess the accuracy and reliability of the model. The results show excellent agreement, with a correlation of 0.976 or higher and a standard error of less than 1% of the head weight Keywords: Biomechanics, biomechanical model, neck, ergonomics, functional assessment Se presenta un modelo dinámico del cuello para su aplicación en valoración funcional o estudios de ergonomía, a partir de datos obtenidos mediante equipamiento biomecánico convencional: sistema de video fotogrametría y plataformas de fuerzas. El modelo utiliza parámetros inerciales de la cabeza y el cuello obtenidos mediante ecuaciones de regresión que se ajustan posteriormente en un proceso de calibración. El movimiento de la cabeza se registra mediante un sistema de video fotogrametría convencional. A partir de las coordenadas de los marcadores se calculan los desplazamientos finitos, velocidades y aceleraciones lineales y angulares. Las fuerzas externas se miden con una plataforma de fuerzas. Mediante un planteamiento de dinámica inversa se estiman fuerzas y momentos a nivel de C7, así como la potencia desarrollada. El modelo se ha validado mediante un estudio experimental con 30 participantes, comparando las estimaciones del modelo con las medidas en una plataforma de fuerzas. Los resultados muestran una correspondencia excelente entre las estimaciones y las medidas experimentales, con una correlación superior a 0.976 y un error estándar inferior al 1% del peso de la cabeza. Palabras clave: Biomecánica, modelo biomecánico, cuello, ergonomía, valoración funcional

En el tratamiento del dolor cervical se emplean equipos y técnicas que no miden la intensidad del dolor del paciente, sino que únicamente permiten observar los daños estructurales de dicha región. Sin embargo, la evaluación de éste dolor se puede llevar a cabo al analizar las variables cinemáticas de los tres movimientos de la articulación cervical: flexo-extensión, flexo-lateral y rotación. En este trabajo estudiaremos la fiabilidad de la técnica de fotogrametría, mediante el uso de una cámara de bajo costo, denominado Kinect V1. La cámara Kinect adquirirá los parámetros cinemáticos del movimiento de flexo-extensión de la articulación del cuello y, técnicas de visión artificial y de procesamiento de imágenes de profundidad/color del sensor Kinect serán empleadas para obtener las trayectorias de los marcadores anatómicos y técnicos. Se utilizará un filtro de Kalman para corregir el seguimiento continuo de las trayectorias de los marcadores técnicos y, consecuentemente, las coordenadas espaciales de cada marcador. Los datos fueron obtenidos de siete sujetos de prueba, entre hombres y mujeres, físicamente sanos. Las edades de los sujetos están comprendidas entre 17 y 40 años. Asociados a las coordenadas de cada marcador técnico, calculamos los parámetros cinemáticos de velocidad angular, aceleración angular y desplazamiento angular, para obtener los parámetros de fiabilidad y correlación entre pruebas. Esto último se realizó al analizar el error estándar medio, el índice de correlación múltiple y los índices de correlación de Pearson, empleados para análisis clínico. El alto índice de correlación entre los ensayos realizados nos permite ratificar la fiabilidad de nuestra metodología.