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Search Results: 1 - 10 of 303181 matches for " Orlando J Domínguez "
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Mejoras en el Desarrollo del Proyecto Final para Estudiantes de Ingeniería Química
Domínguez,Orlando J; Michel,Raquel L;
Formación universitaria , 2010, DOI: 10.4067/S0718-50062010000400006
Abstract: in this work a proposal to improve the development of the final project requirement for chemical engineering students of the national university of salta in argentina, is presented. because this final project course was excessively delaying graduation of students, different teaching methodologies are proposed, including the concept of competence, the problem-based learning and the project-based learning. the change in teaching methods introduced allows reaching one of the main targets of the studying plan, such as finishing in the career in five years, but more important is that a substantial improvement in students learning is achieved.
Estimación óptima de Parámetros y Determinación del Estado Inicial en Modelos Matemáticos No Lineales: Aplicación a un Reactor Químico
Aban,Francisco E; Michel,Raquel L; Domínguez,Orlando J;
Información tecnológica , 2008, DOI: 10.4067/S0718-07642008000600011
Abstract: a novel algorithm is presented for the optimal estimation of parameters and for determining the initial conditions in non linear mathematical models. the work was developed based on models derived from property balance equations. a matrix relation between the variation of degrees of freedom of the process and the variations of the input variables was used to formulate the objective function, which was optimized via orthogonal projection methods. the technique was applied to a continuous stirred tank reactor obtaining results that were consistent with the dynamic behavior of the reactor.
Estimación óptima de Parámetros y Determinación del Estado Inicial en Modelos Matemáticos No Lineales: Aplicación a un Reactor Químico Optimal Parameter Estimation and Determination of the Initial Conditions in Non Linear Mathematical Models: Application to a Chemical Reactor
Francisco E Aban,Raquel L Michel,Orlando J Domínguez
Información Tecnológica , 2008,
Abstract: Se presenta un nuevo algoritmo de cálculo para la determinación de las condiciones iniciales y el ajuste de parámetros en modelos matemáticos no lineales. El trabajo fue desarrollado sobre la base de modelos derivados de las ecuaciones de balance de propiedades. Se estableció una relación matricial entre las variaciones en los grados de libertad del proceso y las variaciones en las variables de entrada para formular la función objetivo, la cual fue optimizada empleando métodos de proyección ortogonal. La técnica elaborada fue empleada en un reactor químico del tipo agitado continuo obteniéndose resultados consistentes con su comportamiento dinámico del reactor. A novel algorithm is presented for the optimal estimation of parameters and for determining the initial conditions in non linear mathematical models. The work was developed based on models derived from property balance equations. A matrix relation between the variation of degrees of freedom of the process and the variations of the input variables was used to formulate the objective function, which was optimized via orthogonal projection methods. The technique was applied to a continuous stirred tank reactor obtaining results that were consistent with the dynamic behavior of the reactor.
Dise?o de Sistemas de Procesos: Un Enfoque Integrador
Domínguez,Orlando J; Finetti,Julián E; Michel,Raquel L; Villanueva,Bárbara M;
Información tecnológica , 2007, DOI: 10.4067/S0718-07642007000500003
Abstract: process design have received wide attention in the literature. a very large number of papers referred to this topic may be find based on: processing systems engineering; classical programming; robust stochastic programming; probabilistic programming; fuzzy logic; genetic algorithms and artificial intelligence. in this paper a new approach is presented, it provides a solution to the problem of process design integrating economics and technologic concepts. uncertainty in making decision is bearing in mind through quality loss functions. the optimization problem is formulated for the system; this is considered composed by subsystems. optimization proceeds with a goal coordinated mechanism with each subsystem seeking their own optimum. the methodology posed on the basis described showed satisfactory results.
Un nuevo Método para Mejorar el Proceso de Producción de Acido Bórico
Domínguez,Orlando J; Serrano,Emilio M; Flores,Jorge E; Michel,Raquel L;
Información tecnológica , 2011, DOI: 10.4067/S0718-07642011000100013
Abstract: this paper proposes a modification to the traditional process for obtaining boric acid with the addition of acid leaching split, to get a highly soluble product, as sodium pentaborate. in this way the mineral can be dissolved without heating, decreasing the amount of leaching reagent, thus saving energy. the ph of the clarified liquid is decreased leading to the precipitation of boric acid. the gangue runs out at different stages of precipitation and filtration, with its successive washes, improving process performance. the produced boric acid has characteristics, such as texture and purity, comparable with that obtained by traditional processes.
Dise o de Sistemas de Procesos: Un Enfoque Integrador Process System Design: an Integrated Approach
Orlando J Domínguez,Julián E Finetti,Raquel L Michel,Bárbara M Villanueva
Información Tecnológica , 2007,
Abstract: Este trabajo pretende contribuir al dise o de procesos, como una alternativa a los diferentes problemas que conlleva el tema. Se propone, como novedad, resolver dicho problema, a través de la integración de conceptos económicos y tecnológicos y resolviendo el problema de la incertidumbre en la toma de decisiones con la consideración de funciones de pérdida de calidad. Se formula un problema de optimización global que puede ser descompuesto a nivel de subsistemas y se resuelve este problema dual empleando un mecanismo de coordinación de metas. Se logra así un planteo metodológico que intenta abarcar varios aspectos del problema en cuestión lográndose resultados satisfactorios. El método propuesto permite resolver el problema de dise o de sistemas de procesamiento en forma consistente con las normas derivadas de la teoría económica con una carga de trabajo similar a la de los métodos usuales, con la ventaja adicional de suministrar mayor información. Process design have received wide attention in the literature. A very large number of papers referred to this topic may be find based on: Processing Systems Engineering; classical programming; robust stochastic programming; probabilistic programming; fuzzy logic; genetic algorithms and artificial intelligence. In this paper a new approach is presented, it provides a solution to the problem of process design integrating economics and technologic concepts. Uncertainty in making decision is bearing in mind through quality loss functions. The optimization problem is formulated for the system; this is considered composed by subsystems. Optimization proceeds with a goal coordinated mechanism with each subsystem seeking their own optimum. The methodology posed on the basis described showed satisfactory results.
Un nuevo Método para Mejorar el Proceso de Producción de Acido Bórico A New Method to Improve the Production Process of Boric Acid
Orlando J Domínguez,Emilio M Serrano,Jorge E Flores,Raquel L Michel
Información Tecnológica , 2011,
Abstract: En este trabajo se propone una modificación al proceso tradicional para obtener ácido bórico, con el agregado fraccionado del ácido lixiviante, para lograr un producto altamente soluble, como el pentaborato de sodio. Con esto se consigue la disolución del mineral en frío con menor cantidad de reactivo lixiviante, ahorrando así energía. Al líquido clarificado se le disminuye el pH logrando así la precipitación del ácido bórico. La ganga se agota con diferentes etapas de precipitación y filtración, con sus consiguientes lavados, mejorando el rendimiento del proceso. El ácido bórico producido presenta características, tales como textura y pureza, comparables con el obtenido por los procesos tradicionales. This paper proposes a modification to the traditional process for obtaining boric acid with the addition of acid leaching split, to get a highly soluble product, as sodium pentaborate. In this way the mineral can be dissolved without heating, decreasing the amount of leaching reagent, thus saving energy. The pH of the clarified liquid is decreased leading to the precipitation of boric acid. The gangue runs out at different stages of precipitation and filtration, with its successive washes, improving process performance. The produced boric acid has characteristics, such as texture and purity, comparable with that obtained by traditional processes.
La vegetación de las geoformas proglaciares en los glaciares Balmaceda, Tyndall, Taraba y Ema, Magallanes, Chile Proglacial landforms vegetation in the Balmaceda, Tyndall, Taraba and Ema glaciers, Magallanes, Chile
Orlando Dollenz,Juan Henriquez,Erwin Domínguez
Anales del Instituto de la Patagonia , 2012,
Abstract: Las geoformas proglaciares sus formas y el tipo de sustrato que las constituyen determinan el tipo de vegetación que las coloniza. En este artículo se describe la vegetación que cubre las geoformas proglaciares en cuatro valles glaciares de la región de Magallanes, analizando la composición florística y la distribución de la riqueza de especies en las geoformas de cada glaciar. se determinó que la sucesión se dirige hacia el climax de los bosques de Nothofagus en los sustratos con buen drenaje, morrenas, aluviones, terrazas lacustres, o hacia el climax de las turberas de ciperáceas o de Sphagnum en los sustratos con drenaje deficiente como depresiones intermorrénicas con arcillas, o material morrénico con arcillas encerrado entre arcos morrénicos. En los valles glaciares la riqueza de especies mayor tiende a estar en las morrenas de fondo, debido a la existencia de numerosos micrositios. se ratifica que las primeras especies arbóreas que se establecen en los valles glaciales son Nothofagus betuloides, N. antarctica y Embothrium coccineum. The forms and the type of substrate that constitutes the proglacial landforms determine the type of vegetation that colonizes them. In this article, the vegetation that covers proglacial landforms in four glacier valleys of the region of Magallanes are described, analyzing the floristic composition and species richness on the landforms of each glacier. One determined that the succession goes towards the climax of the forests of Nothofagus in the substrates with good drainage, moraines, alluviums, lacustrine terraces, or towards the climax of the ciperaceous moorland or Sphagnum bog in the substrates with deficient drainage, like depressions between moraines with clays, or moraine material with clays locked up between moraines arcs. In valleys glaciers the greater species richness tends to be in bottom moraines, due to the existence of numerous microsites. It is ratified that the first tree species that colonize on glacial valleys are Nothofagus betuloides, N. antarctica and Embothrium coccineum.
Successful Interruption of Transmission of Onchocerca volvulus in the Escuintla-Guatemala Focus, Guatemala
Rodrigo J. Gonzalez,Nancy Cruz-Ortiz,Nidia Rizzo,Jane Richards,Guillermo Zea-Flores,Alfredo Domínguez,Mauricio Sauerbrey,Eduardo Catú,Orlando Oliva,Frank O. Richards Jr,Kim A. Lindblade
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000404
Abstract: Background Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of Escuintla-Guatemala in Guatemala, based on World Health Organization criteria for the certification of elimination of onchocerciasis. Methodology/Principal Findings We conducted evaluations of ocular morbidity and past exposure to Onchocerca volvulus in the human population, while potential vectors (Simulium ochraceum) were captured and tested for O. volvulus DNA; all of the evaluations were carried out in potentially endemic communities (PEC; those with a history of actual or suspected transmission or those currently under semiannual mass treatment with ivermectin) within the focus. The prevalence of microfilariae in the anterior segment of the eye in 329 individuals (≥7 years old, resident in the PEC for at least 5 years) was 0% (one-sided 95% confidence interval [CI] 0–0.9%). The prevalence of antibodies to a recombinant O. volvulus antigen (Ov-16) in 6,432 school children (aged 6 to 12 years old) was 0% (one-sided 95% IC 0–0.05%). Out of a total of 14,099 S. ochraceum tested for O. volvulus DNA, none was positive (95% CI 0–0.01%). The seasonal transmission potential was, therefore, 0 infective stage larvae per person per season. Conclusions/Significance Based on these evaluations, transmission of onchocerciasis in the Escuintla-Guatemala focus has been successfully interrupted. Although this is the second onchocerciasis focus in Latin America to have demonstrated interruption of transmission, it is the first focus with a well-documented history of intense transmission to have eliminated O. volvulus.
Environment-dependent heterosis in Drosophila melanogaster
A Domínguez, J Albornoz
Genetics Selection Evolution , 1987, DOI: 10.1186/1297-9686-19-1-37
Abstract:
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