FERImage: An interactive program for fractal dimension, dper and dmin calculation

A computer program has been written for the determination of the D fractal dimension at low scale, of the dper representative parameter of the periodical region at high scale, and the dmin representative parameter of the minimum elemental cell which is repeated in the periodical structure from the variogram. It carries out the simultaneous obtention of the three previous parameters developed by Bonetto and Ladaga. The program also allows to obtain fractal dimension values from the Fourier power spectrum. FERImage has been developed so that the users could choose the rank where the behavior is fractal, not only in the variogram method but also in the Fourier spectrum method.Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señale

FERImage: An interactive program for fractal dimension, dper and dmin calculation

A computer program has been written for the determination of the D fractal dimension at low scale, of the dper representative parameter of the periodical region at high scale, and the dmin representative parameter of the minimum elemental cell which is repeated in the periodical structure from the variogram. It carries out the simultaneous obtention of the three previous parameters developed by Bonetto and Ladaga. The program also allows to obtain fractal dimension values from the Fourier power spectrum. FERImage has been developed so that the users could choose the rank where the behavior is fractal, not only in the variogram method but also in the Fourier spectrum method.Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señale

Backscattered electron images, X-ray maps and Monte Carlo simulations applied to the study of plagioclase composition in volcanic rocks

Zoning patterns in plagioclases are related to abrupt changes in the anorthite content along the crystal growing direction. Accurate characterization of these patterns by electron microprobe is useful to identify magma chamber processes such as recharge, mingling and whole-chamber overturn events. In this work, a new procedure to obtain high resolution quantitative maps of anorthite concentration in single plagioclase crystals is developed. The methodology consists in performing a calibration of backscattered electron images using quantitative X-ray maps. The ultimate resolution of charac- teristic X-rays and backscattered electron signals is studied by Monte Carlo simulation. The method is applied to characterize the chemical composition of a volcanic plagioclase from the Cerro Vilama, Argentina. The results obtained are more precise than the values given by the methods commonly used in the study of plagioclase composition, i.e. the classical profiling by electron microprobe point analysis or the modern backscattered electron image calibration by means of quantitative energy or wavelength dispersive X-ray analysis at a few selected points.Facultad de Ingeniería (FI)Laboratorio de Investigaciones de Metalurgia Física (LIMF)Centro de Investigación y Desarrollo en Ciencias Aplicadas (CINDECA

Standardless quantification by parameter optimization in electron probe microanalysis

A method for standardless quantification by parameter optimization in electron probe microanalysis is presented. The method consists in minimizing the quadratic differences between an experimental spectrum and an analytical function proposed to describe it, by optimizing the parameters involved in the analytical prediction. This algorithm, implemented in the software POEMA (Parameter Optimization in Electron Probe Microanalysis), allows the determination of the elemental concentrations, along with their uncertainties. The method was tested in a set of 159 elemental constituents corresponding to 36 spectra of standards (mostly minerals) that include trace elements. The results were compared with those obtained with the commercial software GENESIS Spectrum® for standardless quantification. The quantifications performed with the method proposed here are better in the 74% of the cases studied. In addition, the performance of the method proposed is compared with the first principles standardless analysis procedure DTSA for a different data set, which excludes trace elements. The relative deviations with respect to the nominal concentrations are lower than 0.04, 0.08 and 0.35 for the 66% of the cases for POEMA, GENESIS and DTSA, respectively. © 2012 Elsevier B.V. All rights reserved.Fil: Limandri, Silvina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Bonetto, Rita Dominga. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Galván Josa, Víctor Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Carreras, Alejo Cristian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Trincavelli, Jorge Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentin

Estudio de la rugosidad superficial de implantes dentales de titanio blastinizados mediante microscopía electrónica de barrido en 3D

Una de las actividades más importantes en el estudio de los implantes dentales de Ti c.p. se encuentra enfocada al uso de modificaciones superficiales mediante métodos físicos o químicos, debido a que ensayos in vivo han puesto de manifiesto que ciertas superficies rugosas producen una mejor fijación por osteoaposición de hueso que la correspondiente a superficies lisas, por lo que resulta necesario realizar una adecuada caracterización de la rugosidad de los mismos. Una gran variedad de tratamientos superficiales son utilizados para incrementar la rugosidad de los implantes dentales de Ti c.p.. De todos ellos, el más utilizado es el blastinizado. En éste, las partículas abrasivas son arrastradas por una corriente de aire hasta impactar con el material siendo algunas de las diferentes variables operativas del proceso el tamaño de partícula y la presión. Existe una gran variedad de parámetros que describen la topografía de las superficies entre los cuales se encuentran los grupos de parámetros de amplitud, híbridos y funcionales. La correcta elección de los parámetros más significativos dependerá de las características del tratamiento superficial utilizado y del objetivo del estudio realizado. En el presente trabajo se realiza una caracterización, por microscopía electrónica de barrido 3D, de la superficie de muestras de Ti c.p. sometidas a diferentes condiciones de blastinizado, proporcionadas por una empresa fabricante de implantes dentalesFil: Kang, Kyung W.. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Pereda, Maria D.. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Lemos, Adriana. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Bilmes, Pablo David. Universidad Nacional de La Plata. Facultad de ingenieria. Laboratorio de Investigaciones de Metalurgia Física; ArgentinaFil: Bonetto, Rita Dominga. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Scarano, Mariano. Kinetical SRL Insumos Medicos; Argentin

Uncertainty studies of topographical measurements on steel surface corrosion by 3D scanning electron microscopy

Pitting corrosion is a damage mechanism quite serious and dangerous in both carbon steel boiler tubes for power plants which are vital to most industries and stainless steels for orthopedic human implants whose demand, due to the increase of life expectation and rate of traffic accidents, has sharply increased. Reliable methods to characterize this kind of damage are becoming increasingly necessary, when trying to evaluate the advance of damage and to establish the best procedures for component inspection in order to determine remaining lives and failure mitigation. A study about the uncertainties on the topographies of corrosion pits from 3D SEM images, obtained at low magnifications (where errors are greater) and different stage tilt angles was carried out by using an in-house software previously developed. Additionally, measurements of pit depths on biomaterial surfaces, subjected to two different surface treatments on stainless steels, were carried out. The different depth distributions observed were in agreement with electrochemical measurements.Facultad de Ingeniería (FI)Facultad de Ciencias ExactasLaboratorio de Investigaciones de Metalurgia Física (LIMF)Centro de Química Inorgánica (CEQUINOR)Centro de Investigación y Desarrollo en Ciencias Aplicadas (CINDECA

Blasting and Passivation Treatments for ASTM F139 Stainless Steel for Biomedical Applications : Effects on Surface Roughness, Hardening, and Localized Corrosion

Due to the combination of good biofunctionality and biocompatibility at low cost, AISI 316 low carbon vacuum melting (LVM) stainless steel, as considered in ASTM F139 standard, is often the first choice for medical implants, particularly for use in orthopedic surgery. Proper surface finish must be provided to ensure adequate interactions of the alloy with human body tissues that in turn allows the material to deliver the desired performance. Preliminary studies performed in our laboratory on AISI 316LVM stainless steel surfaces modified by glass bead blasting (from industrial supplier) followed by different nitric acid passivation conditions disclosed the necessity to extend parameters of the surface treatments and to further consider roughness, pitting corrosion resistance, and surface and subsurface hardening measurements, all in one, as the most effective characterization strategy. This was the approach adopted in the present work. Roughness assessment was performed by means of amplitude parameters, functional parameters, and an estimator of the fractal dimension that characterizes surface topography. We clearly demonstrate that the blasting treatment should be carried out under controlled conditions in order to obtain similar surface and subsurface properties. Otherwise, a variation in one of the parameters could modify the surface properties, exerting a profound impact on its application as biomaterial. A passivation step is necessary to offset the detrimental effect of blasting on pitting corrosion resistance.Laboratorio de Investigaciones de Metalurgia Físic

Backscattered electron images, X-ray maps and Monte Carlo simulations applied to the study of plagioclase composition in volcanic rocks

Zoning patterns in plagioclases are related to abrupt changes in the anorthite content along the crystal growing direction. Accurate characterization of these patterns by electron microprobe is useful to identify magma chamber processes such as recharge, mingling and whole-chamber overturn events. In this work, a new procedure to obtain high resolution quantitative maps of anorthite concentration in single plagioclase crystals is developed. The methodology consists in performing a calibration of backscattered electron images using quantitative X-ray maps. The ultimate resolution of charac- teristic X-rays and backscattered electron signals is studied by Monte Carlo simulation. The method is applied to characterize the chemical composition of a volcanic plagioclase from the Cerro Vilama, Argentina. The results obtained are more precise than the values given by the methods commonly used in the study of plagioclase composition, i.e. the classical profiling by electron microprobe point analysis or the modern backscattered electron image calibration by means of quantitative energy or wavelength dispersive X-ray analysis at a few selected points.Facultad de Ingeniería (FI)Laboratorio de Investigaciones de Metalurgia Física (LIMF)Centro de Investigación y Desarrollo en Ciencias Aplicadas (CINDECA

Uncertainty studies of topographical measurements on steel surface corrosion by 3D scanning electron microscopy

Pitting corrosion is a damage mechanism quite serious and dangerous in both carbon steel boiler tubes for power plants which are vital to most industries and stainless steels for orthopedic human implants whose demand, due to the increase of life expectation and rate of traffic accidents, has sharply increased. Reliable methods to characterize this kind of damage are becoming increasingly necessary, when trying to evaluate the advance of damage and to establish the best procedures for component inspection in order to determine remaining lives and failure mitigation. A study about the uncertainties on the topographies of corrosion pits from 3D SEM images, obtained at low magnifications (where errors are greater) and different stage tilt angles was carried out by using an in-house software previously developed. Additionally, measurements of pit depths on biomaterial surfaces, subjected to two different surface treatments on stainless steels, were carried out. The different depth distributions observed were in agreement with electrochemical measurements.Facultad de Ingeniería (FI)Facultad de Ciencias ExactasLaboratorio de Investigaciones de Metalurgia Física (LIMF)Centro de Química Inorgánica (CEQUINOR)Centro de Investigación y Desarrollo en Ciencias Aplicadas (CINDECA

Blasting and Passivation Treatments for ASTM F139 Stainless Steel for Biomedical Applications : Effects on Surface Roughness, Hardening, and Localized Corrosion

Due to the combination of good biofunctionality and biocompatibility at low cost, AISI 316 low carbon vacuum melting (LVM) stainless steel, as considered in ASTM F139 standard, is often the first choice for medical implants, particularly for use in orthopedic surgery. Proper surface finish must be provided to ensure adequate interactions of the alloy with human body tissues that in turn allows the material to deliver the desired performance. Preliminary studies performed in our laboratory on AISI 316LVM stainless steel surfaces modified by glass bead blasting (from industrial supplier) followed by different nitric acid passivation conditions disclosed the necessity to extend parameters of the surface treatments and to further consider roughness, pitting corrosion resistance, and surface and subsurface hardening measurements, all in one, as the most effective characterization strategy. This was the approach adopted in the present work. Roughness assessment was performed by means of amplitude parameters, functional parameters, and an estimator of the fractal dimension that characterizes surface topography. We clearly demonstrate that the blasting treatment should be carried out under controlled conditions in order to obtain similar surface and subsurface properties. Otherwise, a variation in one of the parameters could modify the surface properties, exerting a profound impact on its application as biomaterial. A passivation step is necessary to offset the detrimental effect of blasting on pitting corrosion resistance.Laboratorio de Investigaciones de Metalurgia Físic