826 research outputs found

    On Analytic Nonlinear Input-output Systems: Expanded Global Convergence and System Interconnections

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    Functional series representations of nonlinear systems first appeared in engineering in the early 1950’s. One common representation of a nonlinear input-output system are Chen-Fliess series or Fliess operators. Such operators are described by functional series indexed by words over a noncommutative alphabet. They can be viewed as a noncommutative generalization of a Taylor series. A Fliess operator is said to be globally convergent when its radius of convergence is infinite, in other words, when there is no a priori upper bound on both the L1-norm of an admissible input and the length of time over which the corresponding output is well defined. If such bounds are required to ensure convergence, then the Fliess operator is said to be locally convergent with a finite radius of convergence. However, in the literature, a Fliess operator is classified as locally convergent or globally convergent based solely on the growth rate of the coefficients in its generating series. The existing growth rate bounds provide sufficient conditions for global convergence which are very conservative. Therefore, the first main goal of this dissertation is to develop a more exact relationship between the coefficient growth rate and the nature of convergence of the corresponding Fliess operator. This first goal is accomplished by introducing a new topological space of formal power series which renders a Fréchet space instead of the more commonly used ultrametric space. Then, a direct relationship is developed between the nature of convergence of a Fliess operator and its generating series. The second main goal of this dissertation is to show that the global convergence of Fliess operators is preserved under the nonrecursive interconnections, namely the parallel sum and product connections and the cascade connection. This fact had only been understood previously in a narrow sense based on the more conservative tests for global convergence

    Creating a Micro-Enterprise for the Development and Marketing of a Chili Sauce Based on Sambo Seeds: Market Analysis

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    The present work was carried out to promote a chili sauce made with the seeds of the sambo fruit – a local variety of pumpkin. Presently, the sauce is consumed only in Ecuador and is prepared using just the fleshy part of the fruit, while the seeds are discarded. The authors of this article see a larger potential application of the fruit in the food industry, as the fruit not only adds a pleasant flavor but is also full of nutrition. They have made a new chili sauce with a base of sambo seeds. The research was carried out using an inductive method, where people were selected at random. Variables such as gender, age, level, and consumption preferences, among others, were analyzed. The study was conducted in Riobamba canton on 164 people, aged 20 and over, considering various aspects. The instrument used was a questionnaire. The results showed that 71.95% of those surveyed consumed chili-based sauces, and 54.88% of them consumed it at least once a week. In addition, 63.41% of them consumed or had consumed sambo seeds, thus denoting that consumers were aware of and were consuming this product. The current research allowed us to innovate the product using correct methods and techniques, and adapt the best use of seeds in the food industry. Keywords: chili, sambo, economic analysis, consumption, commercialization. RESUMEN El presente trabajo se realizó con el objetivo de dar a conocer la aceptación y el beneficio económico de la salsa de ají con adición de semillas del fruto de sambo en el mercado, actualmente su consumo se da en todo el país y se aprovecha únicamente la parte carnosa de la fruta, las semillas son desechadas, por cuanto vemos una potencial aplicación en la industria alimentaria de estas, a más de aportar con sabor agradable aportan nutricionalmente, y se las han adicionado en una salsa de ají, al integrar al mercado una nueva salsa elaborada con este producto icónico además se busca utilizar las semillas de la calabaza local conocida como sambo. Esta investigación se realizó mediante un método inductivo, donde las personas fueron seleccionadas al azar, se analizaron variables como: género, edad, nivel y preferencias de consumo, entre otras. La búsqueda de información fue en el cantón Riobamba, a 164 personas, de 20 años en adelante, considerando varios aspectos; el instrumento aplicado fue cuestionario. Los resultados demuestran que el 71.95% de los How to encuestados consumen salsas elaboradas a base de ají, y de estos 54.88% lo consumen como mínimo una vez a la semana, además que el 63,41% consume o ha consumido semillas de sambo, denotando así que los consumidores conocen y consumen estos productos. La actual investigación nos permitió innovar el producto, utilizando correctamente métodos y técnicas adaptando el mejor uso de las semillas en la industria alimentaria. Palabras Clave: Ají, sambo, semillas, análisis económico, consumo, comercialización

    Batalla de Tulcán

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    Documento extraido del  "Diario de operaciones -año 1862- llevado por el jefe del Estado Mayor Genral, Sergio Arboleda

    Desempeño a largo plazo de secciones de pavimentos existentes de concreto asfáltico

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    RESUMEN: Los pavimentos de carreteras están diseñados para soportar las cargas proyectadas del tr·Æ co y a la vez proporcionar alta calidad para los niveles de servicio. Las grandes cargas que los pavimentos experimentan durante su existencia en conjunto con las condiciones variables de clima y humedad aceleran el proceso de deterioro y podrían causar fallas prematuras a los pavimentos. En esta investigación se realiza un estudio de patología para evaluar el desempeño actual de varios concretos asfálticos. La condición estructural de secciones de concreto asfáltico, localizados en el Estado de Ohio, Estados Unidos, se realizan por medio del método de ensayo del DeØ ectómetro de Impacto (FWD). La interpretación de los ensayos con FWD permite la evaluación de potenciales rehabilitaciones a corto y mediano plazo. La metodología de análisis e interpretación de resultados presentados en este artículo para el caso de los 110 km de pavimento de concreto asfáltico en el Estado de Ohio, se muestra como una técnica valiosa en el caso colombiano para determinar, con mediciones reales de campo, la condición y potencial rehabilitación del sistema de infraestructura que se requiere para garantizar el desarrollo económico sostenible del país.ABSTRACT: Highway pavements are designed to withstand the projected trafÆ c loads while providing a high quality level of service. The large loads that pavements experience during the design life in conjunction with variable climate and moisture conditions accelerate the deterioration process and might cause premature failure of the pavements. In this research, a forensic study to assess the current performance of several asphalt concrete (AC) pavements is conducted. The structural condition of the AC sections, located in the State of Ohio, United States, was determined by means of the Falling Weight DeØ ectometer (FWD) testing method. The evaluation and interpretation of the FWD tests permit the assessment of potential short or medium-term rehabilitation projects. The methodology of analysis and data interpretation presented in this paper for the case of 110 km of asphalt concrete pavement in the State of Ohio, stands as a valuable technique in Colombia to determine, with actual Æ eld measurements, the condition and potential rehabilitation of the infrastructure system that is required to guarantee the sustainable economic development of the country

    Structure, Configuration And Sizing Of Ni Nanoparticles Generated By Ultrafast Laser Ablation In Different Media

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    In recent years, nickel nanoparticles (NPs) have increased scientific interest because of their extensive prospects in catalysts, information storage, large-scale batteries and biomedicine. Several works on Ni NPs generation by laser ablation have appeared in the literature in the last years, using different pulsed laser regimes and different media have been published recently. In this work we analyze the characteristics of species, structure (bare core or core-shell), configuration and size distribution of NPs generated by fs pulse laser ablation over a Ni solid target in n-heptane and water. We explore the presence of NiO-Ni core-shell and hollow Ni (or air-Ni) NPs in the colloids obtained. These were experimentally characterized using AFM and TEM microscopy, as well as Optical Extinction Spectroscopy (OES). Extinction spectra were modeled using Mie theory through an appropriate modification of the complex experimental dielectric function, taking into account a size-dependent corrective term for each free and bound electron contribution. Experimental UV-visible-NIR spectra were reproduced considering a size distribution of bare core, hollow and core-shell structures NPs. In both media, Ni NPs shape and size distribution agrees with that derived from TEM and AFM analysis.954

    FLAT PLATE PULSATING HEAT PIPES WITH DIFFERENT CHANNEL GEOMETRIES FOR HIGH HEAT FLUX APPLICATIONS

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    The thermal performance of flat plate pulsating heat pipes with differentchannel geometries was performed in this experimental work. The testswere accomplished with two channel profiles, round and grooved. One ofthe channel geometries, located on the evaporator, can be considered novel,consisting of a round channel with two lateral grooves. Diffusion bondingtechnology was used to manufacture the PHPs made of two copper flatplates. Distilled water was used as the working fluid with a filling ratio of50% (17.9 ml) of the total volume. The pulsating heat pipes were tested atone position (vertical) under heat loads from 20 up to 2000 W. Theexperimental results showed that both flat plate pulsating heat pipesoperates successfully for high heat fluxes. The lateral grooves reduced thethermal resistance, being principally efficient in lower loads. Besides that,the novel channel considerably anticipated the operation startup. Therefore,a much better performance was obtained by the grooved channel PHP,which was constructed from a simple, low cost modification of thefabrication process

    Determinantes de uma eleição errada ao escolher medicamentos de venda livre

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    Este estudo avalia a probabilidade de confusão do consumidor para seis categorias de medicamentos de venda livre. As estimativas realizam-se com base em um desenho experimental onde o tempo e a presença das marcas são as variáveis manipuladas. Adicionalmente, controla-se por memorização e hábito de consumo da marca. Através de três tipos de análises (tabela de contingência, árvores de decisão e regressão logit), os resultados indicam que a memorização e a presença da marca são duas variáveis que reduzem a probabilidade de confusão. Os resultados não são generalizáveis a outras categorias, sem embargo, a memorização e a presença da marca se mostraram variáveis importantes ao avaliar a probabilidade de confusão do consumidor.Cette étude évalue la probabilité de confusion du consommateur pour six catégories de médicaments de vente libre. Les estimations sont réalisées sur base d'un design expérimental dans lequel le temps et la présence des marques sont les variables manipulées. En outre, un contrôle est effectué par rappel et habitudes de consommation de la marque. Après avoir utilisé trois types d'analyses (tableau de contingence, arbre de régression et régression logit), les résultats indiquent que le rappel et la présence de la marque sont deux variables qui réduisent la probabilité de confusion. Les résultats ne sont pas généralisables pour d'autres catégories, cependant, le rappel et la présence de la marque sont des variables qui résultent importantes pour évaluer la probabilité de confusion du consommateur.Este estudio evalúa la probabilidad de confusión del consumidor para seis categorías de medicamentos de venta libre. Las estimaciones se realizan con base en un diseño experimental donde el tiempo y la presencia de las marcas son las variables manipuladas. Adicionalmente, se controla por recordación y hábito de consumo de la marca. A través de tres tipos de análisis (tabla de contingencia, regresión de árbol y regresión LO GIT), los resultados indican que la recordación y la presencia de la marca son dos variables que reducen la probabilidad de confusión. Los resultados no son generalizables a otras categorías; sin embargo, la recordación y presencia de la marca sí resultan ser variables importantes al evaluar la probabilidad de confusión del consumidor.This study evaluates the probability of confusion among consumers regarding six categories of over-the-counter medications. The estimates are based on an experimental design in which time and the presence of brands are the variables addressed. Additionally, it is controlled using recollection and consumption habits regarding brands. Using three types of analysis (contingency table, tree regression and logic regression), the results show that recollection and the presence of brands are the two variables that reduce the probability of confusion. The results are not applicable to other categories; however, recollection and the presence of brands do turn out to be significant variables when evaluating the probability of consumer confusion
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