This work presents a low-cost device for evaluating Variable Orifice Flow Meters (VOFM) used in medical mechanical ventilation applications. Specifically, the equipment was used to assess the impact of length and thickness on pressure drop for different flows in a rectangular geometry VOFM. A total of six VOFMs, with three different lengths and two different thicknesses, were evaluated. All VOFMs were stimulated with an airflow ranging from 0 $\mathrm{L}.{\mathrm{m}\mathrm{i}\mathrm{n}}^{-1}$ to 90 $\mathrm{L}.{\mathrm{m}\mathrm{i}\mathrm{n}}^{-1}$, with increments of approximately 2 $\mathrm{L}.{\mathrm{m}\mathrm{i}\mathrm{n}}^{-1}$. The experiments conducted with the device showed a strong relationship between pressure drop $∆P$ and flow rate $Q$ in the evaluated VOFMs, with two different zones: one exhibiting non-linear behavior and another showing linear behavior. The results suggest that increased length and decreased thickness lead to higher sensitivity. However, it is essential to reduce the cross-sectional area to mitigate nonlinear effects of the sensor.

Colombia, like other developing countries has been incorporating different electrical vehicles to the automotive national market. While the acquisition of a brand new electric vehicle is still expensive, transformation from used traditional vehicles (combustion) to electrical vehicles has become an interesting economical option. This work presents a performance evaluation of a transformed vehicle from its combustion version. The theoretical and experimental analysis (in rugged geographical reliefs such as Colombia) are necessary to consolidate the validity of this type of proposals at technical, economic and environmental impact levels. The procedure of an electric conversion presented herein showed significant mitigation of greenhouse gases owing to the renunciation of 6,54 L per 100 km and hence avoiding CO emissions: 1,808 g/km and THC + NOx: 0,652 g/km. The procedure included selection of both suitable car (low weight) and electric conversion kit, as well as assembly design, disassembly of combustion system, implementation of electric components. Additionally, experimental tests were performed to determine the behavior with respect to power under some load demands validating the proposed traction model.

El ahorro energético que requiere el país es el resultado de muchos eventos. Una mala administración del recurso hídrico para las hidroeléctricas y la falta de una matriz energética más diversificada para el país son algunas de las causas de un futuro racionamiento. Las energías renovables son una alternativa totalmente viable para nuestro país, tanto para satisfacer la demanda eléctrica como para convertirse en una opción interesante para un transporte verdaderamente sostenible y limpio. El transporte sigue siendo uno de las fuentes con mayor aporte de gases efecto invernadero, causa principal del calentamiento global que se ha venido manifestando progresivamente con climas más cálidos e impredecibles. El proyecto consiste en el desarrollo de un vehículo unipersonal cuyas fuentes energéticas son compartidas entre la energía solar a través de panel fotovoltaico y propulsión humana a través de sistema de transmisión de potencia desde pedales hasta la rueda de tracción. Los complementos energéticos permiten satisfacer demandas en diversas solicitaciones de carga (desde superficies planas hasta pendientes del 12%). El sistema fotovoltaico lo conforman un panel de 345 Wp, una batería de 20 Ah y 48 Vdc (960 Wh), un motor eléctrico de 2 kW. El vehículo alcanza una autonomía (eléctrica) de 2 horas (solo motor a 40 km/h en superficie plana). No obstante en presencia del sol y/o con apoyo del piloto, el vehículo podrá movilizarse sin problema alguno. En la parte mecánica se resalta el trabajo realizado para los sistemas de dirección y tracción. El diseño garantiza que los sistemas no interfirieran para su correcto desempeño. Por ello, la opción de dirección lateral permite una manipulación fácil del piloto sin interferir en el sistema de tracción. Este proyecto ha sido el resultado del trabajo interdisciplinario de estudiantes de los programas de Tecnología Mecánica, Tecnología eléctrica e Ingeniería electrónica.

Through this project, a prototype of video laryngoscope-type medical equipment was developed using low-cost materials and simple manufacturing methods. The development of the prototype aimed to support medical personnel during the intubation procedures in patients who require it, considering that currently this type of device is recommended as the first-line option for patient intubation with suspected or diagnosed COVID-19, however, they are expensive and difficult to acquire. For modeling and prototyping, computer aided design technologies CAD were used, and for manufacturing, computer-aided manufacturing (CAM) technologies (3D printing), as well as video transmission technologies for medical applications. With the development of the Video Laryngoscope, it was possible to obtain a low-cost, fast-to-manufacture and easily accessible device, to provide a useful tool for doctors when addressing the airway in patients with COVID-19, and in general, in any difficult airway scenario as an alternative to direct laryngoscopy.

The results of the research related to the dependency of the frictioncoefficient, µ, between two solid surfaces, on the normal force, N, ispresented. A review of models and experimental results in this area ismade, and results of friction experiments with steel wire bristles for streetsweepers are referred. Many theoretical and experimental works haveshown that µ may increase or decrease when N increases. However, theliterature indicates that mostly µ reduces as N is increased. This mainlyoccurs for small forces and very smooth surfaces. It is concluded thatthis phenomenon may be caused by several factors. Adhesion forces,which affect very smooth surfaces, tend to be significant when N is smalland have the effect of increasing µ. The differences in the contact radii ofthe asperities may also cause this phenomenon. When N is small, a greatnumber of asperities in contact have small radii, and large shear frictionstresses may be developed. In contrast, for large forces, the larger contactradii dominate friction; friction stresses, which are smaller than the shearones, appear producing small friction coefficients. It is also concluded thatthe change from elastic contact, for small forces, to elastic-plastic contact,for larger ones, may reduce µ when N increases.