Search

This work shows the results of a numerical model developed to simulate the CBMS technique for the production of the Fe78Si9B13 metallic magnetic ribbons for application in electronics. The model proposes a numerical approximation to a Vogel-Fulcher-Tammann (VFT) expression as a method in the solidification process. This approximation is introduced into the “compressibleInterFoam” routine, included in the OpenFOAM® suite, originally developed for the simulation of two immiscible, non-isothermal and compressible fluids. This routine solves, the phase fraction transport using the Volume of Fluids (VOF) approach. The boundary conditions imposed in the model were experimentally validated by digital image analysis with a high-speed camera at 5602 fps for the determination of the temperature profiles. The phase change is represented as a growth of several orders of magnitude of the alloy viscosity (μ) as the temperature (T) decreases, reaching solidification around the crystallization temperature (Tg). Also, we establish the condition of initial stability of CBMS process (R > 1.5) for Peclet numbers close to 400, and the validity up to limits of rotation in the wheel close to 40 m s−1. The proposed methodology is validated with previous work. Encouraging results show that the solution of the CBMS process can be adequately simulated with the proposed approach. Fil: Barone, Marcelo Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina Fil: Barceló, Francisco. Universidad Argentina de la Empresa; Argentina Fil: Pagnola, Marcelo Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long". Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnologías y Ciencias de la Ingeniería "Hilario Fernández Long"; Argentina Fil: Larreteguy, Axel Eduardo. Universidad Argentina de la Empresa; Argentina Fil: Marrugo, Andrés G.. Universidad Tecnologica de Bolivar; Colombia Fil: Useche, Jairo. Universidad Tecnologica de Bolivar; Colombia

Chill block melt spinning is used in industrial processes for the production of metallic glasses. It is a rapid solidification process whereby a liquid metal is ejected at high pressure and temperature via a nozzle onto a rotating wheel solidifying in the form of a ribbon. In this work, starting from an alloy with the composition of Fe78Si9B13 (% at.) reproduces the melt spinning technique to get the amorphous magnetic material. A CFD3D model based on the finite volume method (FVM) is proposed. For this purpose, the OpenFoam® open source code is used. In the ribbon production stage, it has been observed that the turbulence involved in the first reported transient lasts a few milliseconds, enough time to study the process with high-speed cameras. We measure the ejection speed by using optical flow on the melt contour. This enables us to check defects in the ribbons, which are predicted with the computational model, such as the case of cracks caused by irregularities in the first formation of the solid layer. The temperature measurement method relies on the fact that the digital camera is sensitive to electromagnetic radiation between 400 and 1000 nm in wavelength and the fact that the image gray level, which is proportional to the temperature T, provided the background illumination level is negligible.

El objetivo del presente trabajo es proponer una metodología para obtener un indice que cuantifique el trabajo cientifico y tecnologico de un investigador de acuerdo a un peso o importancia que surga de una evaluación de acuerdo a politicas cientificas y tecnologicas locales o áreas de responsabilidad del Sector Cientifico y Tecnologico. Este indice involucra proyectos, roles y esfuerzos individuales de investigadores en el Sistema Tecnologico. Este nuevo indice nace de la necesidad de ampliar el indice h propuesto por J.E. Hirsch, ya que este último solo evalúa las presentaciones de documentos editoriales y no el resto de la gestión y rendimiento tecnologico que no es considerado en su idea original. En este sentido, el presente trabajo propone un indice complementario. The aim of this paper is to propose a methodology to obtain an index that quantifies the scientific and technological work of an investigator according to a weight or importance to give an assessment according to the local scientific and technological policies, or areas of responsibility of the Scientific Technology Sector. This index involves projects, roles, and individual efforts researcher's in the technological system to carry out their investigations. This new index born of a need to expand the J. E. Hirsch's h-index since the latter only evaluates presentations of papers and not the rest of the management and technological performance that it is not considered in his original idea. This limitation of the hindex makes it impossible to assess the full profile of a researcher. In this sense, this paper proposes a complementary index. Fil: Pagnola, Marcelo Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnologías y Ciencias de la Ingeniería ; Argentina