Estimación del error en fórmulas que calculan la longitud de contacto en el rectificado

A study of the relative error of the geometric and kinematic contact length formulas found in the literature, both in surface and cylindrical grinding, is performed. For this purpose, the exact formulas have been derived. Under usual grinding conditions, the relative error remains small, < 5%, except for the case of external cylindrical grinding, in which we can find a 2% relative error. It is advisable then to use the exact formulas in order to prevent any kind of error.En este trabajo se estudia el error relativo de las fórmulas geométricas y cinemáticas que aparecen en la literatura y que calculan la longitud de contacto en el rectificado cilíndrico. Para este propósito, se obtienen las fórmulas exactas. En condiciones habituales, el error relativo del rectificado es pequeño, <5%, excepto en el caso de rectificado cilíndrico externo, en el que podemos encontrar un error relativo del 2%. Es entonces recomendable hacer uso de las fórmulas exactas a fin de evitar cualquier tipo de error.Ciencias Experimentale

Modeling thin-film piezoelectric polymer ultrasonic sensors

This paper presents a model suitable to design and characterize broadband thin film sensors based on piezoelectric polymers. The aim is to describe adequately the sensor behavior, with a reasonable number of parameters and based on well-known physical equations. The mechanical variables are described by an acoustic transmission line. The electrical behavior is described by the quasi-static approximation, given the large difference between the velocities of propagation of the electrical and mechanical disturbances. The line parameters include the effects of the elastic and electrical properties of the material. The model was validated with measurements of a poly(vinylidene flouride) sensor designed for short-pulse detection. The model variables were calculated from the properties of the polymer at frequencies between 100 Hz and 30 MHz and at temperatures between 283 K and 313-K, a relevant range for applications in biology and medicine. The simulations agree very well with the experimental data, predicting satisfactorily the influence of temperature and the dielectric properties of the polymer on the behavior of the sensor. Conversely, the model allowed the calculation of the material dielectric properties from the measured response of the sensor, with good agreement with the published values.Fil: González, Martín Germán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; ArgentinaFil: Sorichetti, Patricio Aníbal. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; ArgentinaFil: Cardozo Santiago, Gustavo David. Universidad de Buenos Aires. Facultad de Ingeniería. Departamento de Física; Argentin

A Theorem for Finding Maximum Temperature in Wet Grinding

Surface grinding is an industrial machining process aiming to remove excess material of a workpiece by means of an abrasive wheel which rotates at high speed over its surface. Most of the energy used in the grinding process is converted into heat, and it is accumulated within the contact zone between the wheel and the workpiece [1]. The high temperatures reached can thermally damage the quality of the workpiece, burning the workpiece, causing metallurgical phase transformations, softening (tempering) the surface layer with possible rehardening, onsetting residual tensile stresses, and causing cracks. Therefore, the determination of the temperature field evolution inside the workpiece is of great industrial importance. In order to avoid thermal damage, coolant is usually delivered to the porous grinding zone at a high velocity, so friction is reduced and cooling by convection occurs. Some recommendations for the optimization of the coolant usage are found in.Ciencias Experimentale

Some Remarks on the Self-Exponential Function: Minimum Value, Inverse Function, and Indefinite Integral

Considering the function as a real function of real variable, what is its minimum value? Surprisingly, the minimum value is reached for a negative value of . Furthermore, considering the function () = −, ∈ R and >0, two different expressions in closed form for the inverse function −1 can be obtained. Also, two different series expansions for the indefinite integral of and −1 are derived. The latter does not seem to be found in the literature.Ciencias Experimentale

Influence of magnification on extraction efficiency in laser resonators with non-overlapping beams

The magnification and the Fresnel number determine the mode profile and losses in a bare unstable resonator. Upon inclusion of gain, both the beam pattern and the reflectivity are changed, more than in a stable cavity, because the counter-propagation intensities differ spatially and saturate the amplifier in a way that alters the mode profile, the reflectivity and the conditions of optimal operation. In this paper we present a numerical study of two types of cavities and compute the mode profile and losses in presence of an amplifier that saturates homogeneously. We compare these results with experimental data obtained on a TEA CO2 laser.Fil: González, Martín Germán. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Peuriot, Alejandro Luis. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Garea, María Teresa. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Santiago, G.D.. Universidad de Buenos Aires. Facultad de Ingeniería; Argentin

El balance socio-ambiental

El presente trabajo tiene como finalidad investigar cuáles son los efectos que genera, para las empresas y la sociedad, la emisión de un balance socio-ambiental, y cuál es la incumbencia del contador público nacional en la elaboración y auditoría del mismo. La importancia de este estudio radica en la preocupación y necesidad de los organismos de alcanzar un desarrollo sustentable en el largo plazo, cumpliendo con los estándares de responsabilidad existentes. Además, para dar respuesta a los reclamos y presiones ejercidas por la creciente corriente ambientalista, que de no ser atendidos desembocaría en importantes consecuencias negativas para las instituciones que no se comprometan en el cuidado de la naturaleza. Durante el desarrollo del estudio se hace hincapié en temas que no se pueden obviar si se quiere entender a fondo cuál es la importancia de un balance socio-ambiental, como es el caso de: qué se entiende por responsabilidad social empresaria, qué son los estándares de reportes mediante los cuales se confecciona una balance socio-ambiental, cuál es el público interesado en que los organismos presenten este tipo de balances y en qué situación se encuentra el Estado argentino con respecto a este tema. Los objetivos que se mencionan a continuación son complementarios para alcanzar el objetivo general mencionando precedentemente: Determinar los efectos de la emisión de un balance socio-ambiental para la empresa y la sociedad en general. Conocer las incumbencias del contador público nacional en la emisión de un balance socio-ambiental. Describir los aspectos esenciales a tener en cuenta en la elaboración de un balance socio-ambiental. Evaluar la importancia de un control externo del balance socio-ambiental a través de auditorías. Se parte de la idea de que la presentación de un balance socio-ambiental genera beneficios para las empresas porque es la manera de comunicar a la sociedad la responsabilidad asumida en su accionar y las medidas aplicadas para contribuir al progreso de ésta. Además destacar que es fundamental el papel que desempeña el contador público nacional, tanto en la elaboración como en la posterior certificación de este balance. Esta hipótesis es la que se pondrá a prueba durante el desarrollo de esta investigación.Fil: González, Pablo Fernando. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: San Martín, Germán Ignacio. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas

Analysis of the Use of Color and Its Emotional Relationship in Visual Creations Based on Experiences during the Context of the COVID-19 Pandemic

Color is a complex communicative element. At the level of artistic creation, this component influences both formal aspects and symbolic weight, directly affecting the construction of the message, and its associated emotion. During the COVID-19 pandemic, people generated countless images transmitting the subjective experiences of this event, and the social network Instagram was used to share this visual material. Using the repository of images created in the Instagram account CAM (The COVID Art Museum), we propose a methodology to understand the use of color and its emotional relationship in this context. The proposed methodology consists of creating a model that learns to recognize emotions via a convolutional neural network using the ArtEmis database. This model will subsequently be applied to recognize emotions in the CAM dataset, also extracting color attributes and their harmonies. Once both processes are completed, we combine the results, generating an expanded discussion on the usage of color and emotion. The results indicate that warm colors and analog compositions prevail in the sample. The relationship between emotions and composition shows a trend in positive emotions, reinforced by the results of the emotional relationship analysis of color attributes (hue, saturation, and lighting

Evaluating air emission inventories and indicators from cruise vessels at ports

This paper provides an estimation of air emissions (CO2, NOX, SOX and PM) released by cruise vessels at the port level. The methodology is based on the Bfull bottom-up^ approach and starts by evaluating the fuel consumed by each vessel on the basis of its individual port activities (manoeuvring, berthing and hoteling). The Port of Barcelona was selected as the site at which to perform the analysis, in which 125 calls of 30 cruise vessels were monitored. Real-time data from the automatic identification system (AIS), factor emissions from engine certificates and vessel characteristics from IHS Sea-web database were also collected for the analysis. The research findings show that the most appropriate indicators are inventory emissions per Bport-time gross tonnage^, Bport-time passenger^ and Bport time^. These emission indicators improve our understanding of cruise emissions and will facilitate the work that aims to estimate reliably and quickly the in-port ship emission inventories of cruise ports.Postprint (published version

Los lineamientos de la agenda de Naciones Unidas en las estrategias de lucha antidroga en Colombia

La lucha contra las drogas ha sido un tema fundamental para los intereses de Colombia, ya que este constituye un factor determinante para la extinción de uno de los recursos que alimentan el conflicto armado. A pesar de los esfuerzos institucionales realizados a lo largo de más de cincuenta años en diferentes campos como la administración de justicia, la política económica, la salud pública y las relaciones internacionales, el narcotráfico no ha desaparecido, principalmente porque persiste una estructura de incentivos que promueven la relación de la población campesina con el superávit del producto ilícito.The drugs war has been an essential topic for Colombia´s interests, since this is a determining factor for the extinction of one of the resources that fuel the armed conflict. Despite institutional efforts made over more than fifty years in different fields such as justice, economic policy, public health and international relations, drug trafficking has not disappeared, mainly because an incentive structure that promote the relationship between the rural population and the surplus of the illicit proceeds remains.Politólogo (a)Pregrad

Análisis de la política institucional del Ejército Nacional como garantía de no repetición : la nueva doctrina Damasco

222 páginasThis research was oriented to inquiry the most relevant factors of the institutional policy of the Colombian National Army implemented for the post-conflict, with the idea to verify whether it is a guarantee of non-repetition of serious human rights violations and serious violations of International Humanitarian Law . Special attention was paid to the framework and concepts of the military doctrines analyzed, to reconfirm Damascus's promise, about the change in the operational perspective and the conceptual leap that makes the National Army a multimission force interoperable with NATO forces. As a relevant conclusion, it was found that the new Damascus Doctrine reoriented the conception of the War Driving Function, granting more leeway to subordinates and subalterns, which resulted in disrumptions in the chain of command. Furthermore, some weaknesses were found in the provisions of the Manuals of the doctrine; therefore, it could not be verify that Damascus is a guarantee of non-repetition.Esta investigación se orientó a indagar los factores más relevantes de la política institucional del Ejército Nacional de Colombia implementada para el posconflicto, con la idea de comprobar si es una Garantía de no repetición de graves violaciones a los derechos humanos y graves infracciones al Derecho Internacional Humanitario. Se prestó especial atención a la estructura y los conceptos de las doctrinas analizadas, para corroborar la promesa de Damasco, sobre el cambio en la perspectiva operacional y el salto conceptual que convierte al Ejército Nacional como fuerza multimisión interoperable con las fuerzas de la OTAN. Como conclusión relevante se encontró que la nueva Doctrina Damasco, reorientó la concepción de la Función de Conducción de la Guerra, otorgando mayor libertad de acción a los subordinados y subalternos, lo cual generó que se rompiera la cadena de mando. Además, se encontraron algunas falencias en las disposiciones de los Manuales de la doctrina; por tanto, no se pudo afirmar que Damasco sea una Garantía de no repetición.Magíster en DerechoMaestrí