Papers by mario rosenberger
En la produccion artesanal de alimentos se utilizan, por lo general, cubas o tanques calefacciona... more En la produccion artesanal de alimentos se utilizan, por lo general, cubas o tanques calefaccionados de pequenas dimensiones para efectuar los procesos termicos de pasteurizacion o esterilizacion, necesarios para extender la vida util de los mismos. Particularmente la pasteurizacion de leche a pequena escala se lleva a cabo en los equipos antes mencionados, manteniendo la temperatura del producto a 72o C durante 15 a 20 segundos. Este trabajo tiene por objetivo evaluar la fluido-dinamica y distribucion de temperaturas que se desarrollan en un pasteurizador cilindrico conteniendo agua sometido a calefaccion mediante resistencias electricas. Para ello se modelan numericamente dos casos, conveccion natural y circulacion forzada mediante agitacion por reflujo, comparando entre ambas la eficiencia del diseno y el tiempo en alcanzar el estado estacionario. Se considero un regimen laminar y se trabajo con un rango de temperaturas de la resistencia entre 63 a 82o C, y en el caso de circulac...
Polynomial functions for direct calculation of the surface free energy developed from the Neumann Equation of State method
arXiv (Cornell University), Mar 12, 2023
Smooth semicompact multilayer coating of TiO2 obtained by combining anodic oxidation and sol-gel techniques
Surface & Coatings Technology, Dec 1, 2022
International Journal of Biomaterials, 2015
The bio-and hemocompatibility of titanium alloys are due to the formation of a TiO 2 layer. This ... more The bio-and hemocompatibility of titanium alloys are due to the formation of a TiO 2 layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO 2 , anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO 2 anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500 ∘ C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment.
Identification of shadows in the Atlantic Forest for preservation monitoring
Remote Sensing Applications: Society and Environment, Jun 1, 2023
International Journal of Adhesion and Adhesives, May 1, 2023
The Neumann Equation of State (EQS) allows obtaining the value of the surface free energy of a so... more The Neumann Equation of State (EQS) allows obtaining the value of the surface free energy of a solid () from the contact angle () of a probe liquid with known surface tension (). The value of is obtained by numerical methods solving the corresponding EQS. In this work, we analyzed the discrepancies between the values of obtained using the three versions of the EQS reported in the literature. The condition number of the different EQS was used to analyze their sensitivity to the uncertainty in the values. Polynomials fit to one of these versions of EQS are proposed to obtain values of directly from contact angles (()) of particular probe liquids. Finally, a general adjusted polynomial is presented to obtain the values of not restricted to a particular probe liquid ((,)). Results showed that the three versions of EQS present non-negligible discrepancies, especially at high values of. The sensitivity of the EQS to the uncertainty in the values of is very similar in the three versions and depends on the probe liquid used (greater sensitivity at higher) and on the value of of the solid (greater sensitivity at lower). The discrepancy of the values obtained by numerical resolution of both the fifth-order fit polynomials and the general fit polynomial was low, no larger than ±0.40 mJ/m 2. The polynomials obtained allow the analysis and propagation of the uncertainty of the input variables in the determination of in a simple and fast way.
Mecánica Computacional, 2013
Resumen. El proceso de pasteurización consiste en el calentamiento de líquidos hasta una temperat... more Resumen. El proceso de pasteurización consiste en el calentamiento de líquidos hasta una temperatura tal que permita la eliminación de los microorganismos patógenos y de esta forma de extender el tiempo vida útil. El tiempo de pasteurización es un limitante importante, ya que si el tratamiento térmico es excesivo el producto pierde su valor nutritivo y puede incluso contraer características desagradables en su gusto, aroma, color y textura. La duración del proceso debe ser la óptima, ya que si es breve no se alcanza a destruir el número suficiente de microorganismos y, por lo tanto, podría volver a aumentar su número hasta niveles que pongan en riesgo la salud de los consumidores.
Acta Crystallographica Section A, Aug 22, 2011
Acta Crystallographica Section A, Aug 23, 2005
Our Hot Filament Chemical Vapor Deposition (HFCVD) apparatus, modified by the introduction of a p... more Our Hot Filament Chemical Vapor Deposition (HFCVD) apparatus, modified by the introduction of a powder flowing system, allows the use of different kinds of solid powders as reactants. By the use of Fe(NO 3) 3 in acetone as a catalyst, and carbon nanoparticles as reactants, we successfully synthesized Single Wall Carbon Nanotubes (SWNTs). We proved able to control orientation of the deposit as well as the area of growth [1]. By slightly varying experimental conditions, we obtained a nanocrystalline diamond coating on SWNT wall [2]. The use of diesel soot as SWNT precursor has been investigated, too: highly oriented growth of tubular structures through catalysed reaction occurs all over the substrate with abundance of coiled, intriguing structures. Commercial graphite with powders' size in the micron range, in the same experimental conditions, lead to Multi Wall Carbon Nanotube rich deposits. Selected area growth of nanotubes can be achieved by means of catalyst dispersions on Si/SiO 2 patterned substrates or from selectively sputtering metallic iron
JOM, Aug 10, 2017
Titanium dioxide (TiO 2) coatings are currently produced for hemocompatible and photocatalytic ap... more Titanium dioxide (TiO 2) coatings are currently produced for hemocompatible and photocatalytic applications by using two techniques: sol-gel and anodic oxidation. In this review, the research advances on TiO 2 nanofilms produced with these techniques are presented, with a focus on different aspects such as process parameters, morphology, roughness, crystal structure, adhesion, wear and erosion resistance, corrosion resistance, hemocompatibility, toxicity, plaque and bacterial adhesion, and heterogeneous photocatalysis of immobilized porous material.
Advances in Nanostructured TiO2 Coatings for Industrial Applications
CRC Press eBooks, Feb 24, 2023
Modelling the interaction of particles with a concave solidifying interface
The interaction of a foreign particle with a solidifying interface is studied with numerical mode... more The interaction of a foreign particle with a solidifying interface is studied with numerical modelling. The model includes two main forces; the drag and the pushing forces. The drag force is calculated from the fluid flow, the repulsion force by the Lifshitz-Van der Waal force. The thermal field is decoupled from the force field. The model is applied to a metallic matrix and particles with similar and higher thermal conductivities; giving planar and concave interface shapes respectively. The steady state of pushing is studied for the same conditions and different solidification velocities and particle radius. The results show that a concave interface shape generates higher drag forces about one order the magnitude higher than those for a planar interface. As a result the critical velocity is less than that corresponding to a planar interface. The magnitude of the effect of the different parameters in the phenomenon is presented and discussed.Fil: Agaliotis, Eliana Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Grupo de Materiales, Modelización y Metrología; ArgentinaFil: Rosenberger, Mario Roberto. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Grupo de Materiales, Modelización y Metrología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Schvezov, Carlos Enrique. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Grupo de Materiales, Modelización y Metrología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Ares, Alicia Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Grupo de Materiales, Modelización y Metrología; Argentin
Mecánica Computacional, Nov 16, 2019
XXIII Congreso de Métodos Numéricos y sus Aplicaciones (ENIEF) (La Plata, 7 al 10 de noviembre 2017), Dec 2, 2017
Optimizing of the design of a prosthetic heart valve with three leaves
INTRODUCTION Mechanical heart valves have a long life; however their blood flow performance is po... more INTRODUCTION Mechanical heart valves have a long life; however their blood flow performance is poor. In view of this it results justifiable to look for improvements in their design in order to obtain a better performance, closer for instance to that of a native aortic valve. One approach followed by the present authors is to employ three leaves and the pivot system in the peripheral part of the valve. With these it is expected to obtain a mostly central flow, a low thrombogenicity and a smooth operation.
The influence of sol-gel dip-coating and anodic oxidation process parameters in producing thin Ti... more The influence of sol-gel dip-coating and anodic oxidation process parameters in producing thin TiO2 films is studied. As the size of the films is in the order of nanometres (20-140 nm), to obtain a precise measurement of their thickness and analyse their crystalline structures, glancing incidence angle X-ray techniques (X-ray reflectometry and Xray diffraction) using synchrotron radiation are used. A relationship between the colour and thickness of the films was found. This enables the film thickness to be estimated by the film colour. Within the range of the parameters studied, both techniques produce thin films with smooth surfaces which at most reproduce the roughness of the polished substrate. Independently of the technique, thermally-treated films thicker than 30 nm presented different crystalline structures with anatase and rutile phases.
ANALES AFA, Aug 1, 2013
Se estudia la erosión de materiales utilizados en la construcción de prótesis de válvulas cardíac... more Se estudia la erosión de materiales utilizados en la construcción de prótesis de válvulas cardíacas, Acero inoxidable 316 y Poli-metacrilato de metilo (PMMA) a niveles de desgaste bajos, esperados en estos dispositivos. Como material erosivo se utilizó SiC 220 mesh (65 μm de diámetro), en dos composiciones diferentes: 0,1 y 1 % en peso, suspendidas en una solución de glucosa al 50%P/P, (viscosidad de 0,01540 kg/(m.s)). Se usó un flujo de 2200 cm 3 /min y dos tamaños de boquillas de: 2,3 y 6,4 mm de diámetro, en dos ángulos de incidencia diferentes, 60º y 90º. Los ensayos se realizaron por un período de 11 horas. Se partió de probetas de PMMA y Acero inoxidable 316 pulidas a espejo. Las escaras de desgaste se observaron al microscopio óptico. El tipo de fallas observadas en las probetas luego de los ensayos fueron: Puntos o cráteres (pequeños y grandes), Rayas largas, Rayas cortas y Rayas en forma de comas. En PMMA el desgaste se incrementó al aumentar la cantidad de partículas erosivas, tanto en los ensayos a 60º como a 90º. En cambio, no se observaron cambios en el nivel de con el ángulo de incidencia. En el acero inoxidable 316 se observó un incremento en el nivel de desgaste al reducir el ángulo de incidencia, de 90º a 60º.
Diseño De Una Prótesis De Válvula Cardiaca De Tres Valvas
Mecánica Computacional, 2005
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Papers by mario rosenberger