El sistema de frenado de un automóvil debe satisfacer un conjunto complejo de requerimientos, siendo la seguridad lo más importante. En el diseño de estos sistemas, influye directamente una correcta geometría y una selección adecuada del material para garantizar su correcto funcionamiento. El objetivo de este trabajo, es proponer un nuevo arreglo geométrico para la optimización del flujo de aire en un disco de freno automotriz, teniendo en cuenta pilares de ventilación fundamentado en perfiles aerodinámicos tipo N-38. Para validar esta propuesta de diseño, fue construido un prototipo a escala 1:1 por medio de manufactura aditiva y de esta manera poder medir el campo de velocidades generado en la zona de succión y descarga utilizando Velocimetría por Imágenes de Partícula (VIP). El arreglo geométrico se llevó a cabo bajo dos condiciones de velocidad angular: 541 y 941 rpm. Los resultados obtenidos muestran la optimización de la velocidad del aire en la zona de descarga de 0.2121 y 0.743 m/s respectivamente para los rangos de velocidades; con lo que se evidencio la importancia de diseños experimentales con los cuales se pueda mejorar la geometría de los frenos de disco autoventilados y de esta manera garantizar la eficiencia y seguridad del sistema.

The first component for the manufacture of masonry products used in construction is clay, which provides the plasticity that facilitates the molding and handling of the product. The second component is the feldspar in form of alumina (Al 2 O 3) which is used as flux. The third one is silica (SiO 2) which is used as a filling material and stabilizer. These

Nowadays, in Colombia, specifically in the north-eastern, in Santander region, the process of mixing the ceramic paste used to manufacture masonry products for construction (H- 10 bricks, tiles, roof tiles, etc.) is done manually. For this reason, approximately 70% of the companies do not possess the technological tools which facilitate the prediction of the behavior of the raw material (clay). The main objective of this research is to formulate mixtures at a laboratory-level in order to verify the physical properties of ceramic raw materials used by a company which was takenas a sample. The research development was carried out through the execution of tests and laboratory analysis, taking into account the formulation of mixtures with the help of Statgraphics Centurion XV software in order to obtain combinations of raw materials according to the requirements of the current standard techniques. The results demonstrate the importance of using statistical programs for the improvement of systems and processes, predicting the behavior of raw materials as well as conducting pilot tests, taking into account the laboratory analyses in the ceramic industry. Conclusions: The results show that the mixture combinations obtained have the necessary parameters to meet the current standards such as resistance and absorption, which will optimize the economic and physical resources of the company, as well as the quality of the final product.

Desarrollar modelos matemáticos para los motores de generación de energía más confiables que permitan proponer un uso eficiente de los combustibles y aumentar la eficiencia de conversión energética, se ha convertido en uno de los principales objetivos de los trabajos de investigación en el área. Con el fin de estudiar el fenómeno liberación de calor en los cilindros de un motor a gas natural J612 Jenbacher de 2 MW a partir de variables medias disponibles en registros operacionales, se ha propuesto un modelo semifísico a partir de balances de masa, energía, ecuaciones constitutivas y regresiones estadísticas. Los resultados muestran que a partir del modelo propuesto del calor rechazado con un coeficiente de determinación de 0.99, el permiten alcanzar un error relativo máximo de 2% en modo isla y del 4% operando en red para la estimación de la temperatura de los gases a las salidas de los cilindros. Así mismo, el modelo permite determinar la fracción de calor perdido en los cilindros en función de la energía aportada por el gas natural

A quantitative diagnosis of the ergonomic valuation is presented for people who work as fitters in the footwear sector due to the use of chairs that are not related to the users' anthropometric measurements. To estimate the inconvenience, a population of 24 people working as fitters was taken, and a survey was carried out divided into three parts: analysis of the activity, ergonomics of the workplace and information on the chair, in which it was found that the dimensions of the chair are 21% below the recommended measurements, according to the anthropometric measurements of the user. Similarly, based on the General Shackel Comfort Scale, it was found that there is discomfort in the lower back, mid back, buttocks and neck mainly. Subsequently, a sample of 15 fitters with an average experience of 33.4 years was taken from a specialized company to carry out an osteomuscular valuation. It was found that the most representative conditions are carpal tunnel syndrome, musculoskeletal disorder, lowered shoulder and lordosis, with 80%, 73%, 60% and 60% of people affected, respectively, given the positions they adopt, the use of a non-ergonomic chair and repetitive movements that the work 3198 Sofia Orjuela Abril et al. requires. It is concluded from the information collected, the perception of the users and the osteomuscular valuation that the seats used for the task are not adequate to the anthropometric dimensions of the fitters and generate effects on the health of the worker that impact on their comfort, quality of life and productivity.

Designing cams by BézierCurves has become increasingly common, since the mathematical development of this method is less complex. Bezier curves are Bernstein-based polynomials under a unitary domain, and in that sense, this article presents the design of a cam using Bezier curves of degrees 5, 7 and 9. And beyond, this article seeks to show the variation of the effective effort of Von Mises in a cam-follower mechanism composed of a disc cam and a roller follower with translation movement and force closure. The expressions that allow determining the variation of Von Mises' effort for each of the curves used are presented. This variation is presented by means of graphs in which it is observed that as the degree of the curve increases, the magnitude of the efforts is greater, and this increases the probability of failure in the mechanisms. In addition, it was found that there is an inverse relationship between the stress and the radius of the primary circle of the cam

Numerous research works have studied the stress distribution in sections with geometric discontinuities and the relationship with the theoretical factor of stress concentration using the finite element method. These works have dealt with topics such as the influence of the length of pieces on the factor in rectangular orthotropic plates; The behavior of the stress concentration factor on short shafts with section changes under bending loads; The theoretical factor of stress concentration in flat parts subjected to tension with "U" grooves; The estimation of the theoretical stress concentration factor for a flat plate with two holes subjected to tension loads. Other studies have compared the stress distribution by applying three methods: elasticity theory, finite element analysis and experimental techniques. Results show that the finite element method is effective in solving the problem. The goal of this research is to determine the theoretical stress concentration factor for a flat plate with two holes subjected to bending applying the finite element method. The modeling of the plate, the application of the loads, the mesh generation and the simulation of the stress distribution were made using the software 4870 Carlos Acevedo Peñaloza et al. ANSYS® Workbench. Four holes with different sizes were worked and for each of them 10 different values of the distance between centers were taken. In this way the relationship between the factor , the size of the holes and the distance between centers was found. This information is of great importance for the design of mechanical elements that are under these conditions.

This article presents the study of the surface roughness inside cylinders, machined by honing in industrial honing machines, with a detailed review of the variability of the values obtained in the measurement of the machined surface. The determination of the amount of measurement data on the cover is displayed to get characteristic mean values of the measured surface. For this reason, and due to the randomness of the surfaces machined by honing, an experimental study has been proposed to carry out this analysis, where the roughness has been measured with a roughness meter with a contact probe, since this type of instrument is widely used academically and especially industrially, and is apparently standardized by international standards such as ISO 3274 or ASME B46.1.