An extension of Gander’s result for quadratic equations

AbstractIn the study of iterative methods with high order of convergence, Gander provides a general expression for iterative methods with order of convergence at least three in the scalar case. Taking into account an extension of this result, we define a family of iterations in Banach spaces with R-order of convergence at least four for quadratic equations

A note on a modification of Moser's method

We use a recurrence technique to obtain semilocal convergence results for Ulm's iterative method to approximate a solution of a nonlinear equation F (x) = 0fenced((x n + 1 = x n - B n F (x n),, n 0,; B n + 1 = 2 B n - B n F (x n + 1) B n,, n 0 .))This method does not contain inverse operators in its expression and we prove it converges with the Newton rate. We also use this method to approximate a solution of integral equations of Fredholm-type. © 2007 Elsevier Inc. All rights reserved

Analysis of columns with sheardeformation using finite element method and equivalent distributedloads

En este trabajo se aplica un procedimiento basado en el concepto de Acción Repartida Equivalente (ARE) al análisis, por el Método de Elementos Finitos (MEF) formulado en desplazamientos y solución nodal exacta, de pilares con deformación por cortante de acuerdo con la teoría de Timoshenko. Los resultados obtenidos con la metodología ARE-MEF, en los casos analizados, ponen de manifiesto que con un número muy reducido de elementos (uno y dos en los ejemplos desarrollados) se alcanza gran exactitud en desplazamientos, giros y esfuerzos. Sin embargo con otras metodologías formuladas en desplazamientos, como por ejemplo la de integración reducida, se requiere del orden de 40 elementos para alcanzar resultados similares. Asimismo en el presente trabajo, a partir del MEF con solución nodal exacta se determinan de una forma directa y sistemática las funciones de estabilidad y la carga de pandeo para el pilar de Timoshenko.This paper describes a procedure based on the concept of Equivalent Distributed Loads (EDL) applied to the Finite Elements Method (FEM) based on displacements and exact nodal solution of columns subject to shear deformation in accordance with the Timoshenko beam theory. The results obtained using this “EDL-FEM” methodology, in the cases studied, show that a high level of exactness in displacements, rotations as well as shear force and bending moment is obtained with a very small number of elements (one or two in the examples developed). Other methodologies based on displacements, such as reduced integration, require on the order of 40 elements to achieve similar results. The stability functions and buckling load for the Timoshenko beam are also determined in a direct and systematic way from the FEM with exact nodal solution.Peer Reviewe

Friction losses in valves and fittings for power-law fluids

Data on pressure drop were obtained in stainless steel, sanitary fittings and valves during laminar and turbulent flow of aqueous solutions of sucrose and xanthan gum, which were selected as model fluids. The rheological properties of these solutions were determined and the power-law model provided the best fit for experimental data. Friction losses were measured in fully and partially open butterfly and plug valves, bends and unions. Values of loss coefficients (k f) were calculated and correlated as a function of the generalized Reynolds number by the two-k method. The model adjustment was satisfactory and was better in the laminar flow range (0.976 < r² < 0.999) than in the turbulent flow range (0.774 < r² < 0.989). In order to test the adequacy of the results for predicting loss coefficients during flow of real fluids, experiments were conducted with coffee extract. Comparison between experimental and predicted loss coefficients showed very good agreement.455463Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

La seca de encinas y alcornoques en Andalucía : decaimiento y enfermedad

El decaimiento forestal es una enfermedad de etiología compleja, resultado de la acción de un número variable de factores bióticos y abióticos que causan un deterioro gradual y general de los árboles afectados, hasta su muerte. Los factores implicados en el decaimiento de los Quercus en Andalucía son factores predisponentes de tipo selvícola, alteraciones climáticas como factor incitante, y plagas y enfermedades como factores contribuyentes. Entre las enfermedades implicadas en Seca de los Quercus destacan, por orden de importancia, la podredumbre radical causada por Phytophthora cinnamomi, los chancros de tronco y ramas causados por Botryosphaeria spp. y el chancro carbonoso causado por Biscogniauxia mediterranea. No obstante, las dos primeras enfermedades tienen una especial incidencia en distintas zonas de Andalucía de forma independiente, no asociadas al decaimiento. En el presente artículo se exponen las medidas de control disponibles contra estas enfermedades de los Quercus y se plantea la necesidad de disponer de un diagnóstico preciso en cada caso para abordar dicho control con garantías, ya que no cabe encontrar soluciones únicas que resulten eficaces con independencia de la naturaleza del problema._____________________________________The forestry decline is a complex disease, as a result of the action of a changeable number of biotic and abiotic factors that cause a gradual and general deterioration of the affected trees, until their death. The factors involved in the Quercus decline in Andalusia are predisposing factors like silvic, climatic alterations as inciting factor, and insect pest and diseases as contributing factors. Between the diseases involved in oak decline stand out, in order of importance, the root roting caused by Phytophthora cinnamomi, the chancres of trunk and branches caused by Botryosphaeria spp. and the charcoal canker caused by Biscogniauxia mediterranea. Nevertheless, the first two diseases have a special effect on different zones of Andalusia in different ways, not associated with the decay. In this article we expose the available tools of disease control. We emphasizes the need of having a precise diagnosis in every case to approach the control with guarantees, since there is no chance of finding only one efficient solution regardless of the nature of the problem

Catalytic oxidation of emissions in combustion systems for forest biomass, using catalysts with TiO2 support

A study was made of the catalytic oxidation of a model mixture of effluents from forest biomass combustion equipment, consisting principally of methane (CH4), naphthalene (C10H8), carbon monoxide (CO) and oxygen-poor air (10% O2, balance N2), in a laboratory reactor, using MeOx/TiO2 catalysts (Me = Fe, Cu or Mn), prepared using incipient wetness impregnation. It was observed that the addition of metal oxides to the TiO2 increases catalytic activity in the combustion of all the contaminants present in the model effluent (CH 4, C10H8 and CO). The catalysts were characterised using the following techniques: SBET, XRD, DTG/DTA and TPD-NH 3; and from these it was observed that the support presented only the anatase phase in all the catalysts, despite having been subjected to temperatures in excess of 1.000 K during combustion. The highest acidity among all the solids tested, measured by TPD-NH3, was obtained for the FeOx/TiO2 catalysts, which were also those which showed the greatest catalytic activity. This high level of activity may be related to the formation of isolated metallic phases; i.e. hematite (Fe2O3), which would be the active phase in the combustion of C10H8 and CH4. On the other hand, with to respect to the 5 % wt. values of Me/TiO2 (Me: Fe, Cu y Mn) catalysts, the CuO/TiO2 catalyst shows greater activity than Fe2O3/TiO2 and MnOx/TiO2 for the oxidation of CO, which would be related to the formation of CuO on the TiO2 surface. The formation of mixed phases between the metals and the TiO2 was not observed. The SBET of the most active catalyst, Fe2O3/TiO2 (where Fe is 5% w/w in value), was not subject to any changes during the reaction

Solving the random Cauchy one-dimensional advection-diffusion equation: Numerical analysis and computing

[EN] In this paper, a random finite difference scheme to solve numerically the random Cauchy one-dimensional advection-diffusion partial differential equation is proposed and studied. Throughout our analysis both the advection and diffusion coefficients are assumed to be random variables while the deterministic initial condition is assumed to possess a discrete Fourier transform. For the sake of generality in our study, we consider that the advection and diffusion coefficients are statistical dependent random variables. Under mild conditions on the data, it is demonstrated that the proposed random numerical scheme is mean square consistent and stable. Finally, the theoretical results are illustrated by means of two numerical examples.This work has been partially supported by the Ministerio de Economia y Competitividad grant MTM2013-41765-P. Ana Navarro Quiles acknowledges the doctorate scholarship granted by Programa de Ayudas de Investigacion y Desarrollo (PAID), Universitat Politecnica de Valencia. M.A. Sohaly is also indebted to Egypt Ministry of Higher Education Cultural Affairs for its financial support [mohe-casem(2016)].Cortés, J.; Navarro-Quiles, A.; Romero, J.; Roselló, M.; Sohaly, M. (2018). Solving the random Cauchy one-dimensional advection-diffusion equation: Numerical analysis and computing. Journal of Computational and Applied Mathematics. 330:920-936. https://doi.org/10.1016/j.cam.2017.02.001S92093633

Análisis del funcionamiento de una red colectiva ante distintas estrategias de riego en parcela

En zonas colectivas de riego, la tarifa a pagar por los agricultores está muy condicionada con el gasto energético de los equipos de bombeo, relacionada a su vez con la cantidad de agua aplicada a los cultivos. Así pues, es necesario el desarrollo de herramientas de ayuda a la toma de decisiones que busquen mejorar la eficiencia en el uso del agua y la energía, sin comprometer el rendimiento y productividad de los cultivos. El objetivo del trabajo es analizar el consumo energético en una estación de bombeo de una red colectiva de riego a la demanda ante distintos escenarios de riego en parcela y de presiones en la cabecera. La metodología propuesta ha sido aplicada a la zona regable de Tarazona de La Mancha (Albacete, España). Se han establecidos dos manejos de riego en parcela (con y sin déficit) para los principales cultivos de la zona y diferentes estrategias de presiones en la cabecera (variable y fija), para analizar el efecto sobre la eficiencia y consumo energético del bombeo. Para ello, se ha utilizado una herramienta de simulación desarrollada en MATLAB®, en combinación con el motor de cálculo EPANET®, y se ha aplicado como ejemplo a un día de elevada demanda de agua en la red. Los resultados indican que la utilización de presión en cabecera variable y manejo deficitario, genera ahorros energéticos de 12,43% en relación al mismo manejo con presión fija

Comparison of a proprioceptive training program on stable base and unstable base

El objetivo de este estudio fue comparar dos programas de entrenamiento propioceptivo sobre base estable (G1) y base inestable (G2). Durante 5 semanas, 18 jugadores de fútbol profesional se sometieron a un programa de entrenamiento propioceptivo, 9 formaron el G1 y 9 G2. Se aplicó el Standard Excursion Balance Test (Test de Estrella) antes y después de la intervención. Los resultados intragrupo mostraron diferencias significativas en las variables ANT.IZDO; ANTLAT.IZDO; POST.D y ANTMED.D (p<0,005) para el G1 y ANT.D; ANT.IZDO; POSTMED.D; POSTMED.IZDO Y MED.D (p <0,005) para el G2. No se hallaron evidencias significativas entre el entrenamiento en base estable y base inestable para la mejora del equilibrio y la estabilidadThe aim is to compare two proprioceptive training programs on a stable (G1) and an unstable (G2) base in terms of balance and stability. During a 5 week period, 18 professional football players underwent a proprioceptive training program, 9 in G1 and the other 9 in G2. The Standard Excursion Balance Test was applied before and after the intervention program. Significant intragroup differences were found in the variables LEFT FRONT, ANTEROLATERAL LEFT (ANTLAT.LEFT), BACK RIGHT and ANTEROMEDIAL RIGHT (ANTMED.RIGHT) (p<0,005) for the G1, and FRONT RIGHT, FRONT LEFT, POSTMED.RIGHT, POSTMED.LEFT and MED.RIGHT (p <0,005) for G2. We conclude that there are no significant differences between the unstable base training and training stable base regarding improvement in balance and stabilit

Dynamics of a new family of iterative processes for quadratic polynomials

AbstractIn this work we show the presence of the well-known Catalan numbers in the study of the convergence and the dynamical behavior of a family of iterative methods for solving nonlinear equations. In fact, we introduce a family of methods, depending on a parameter m∈N∪{0}. These methods reach the order of convergence m+2 when they are applied to quadratic polynomials with different roots. Newton’s and Chebyshev’s methods appear as particular choices of the family appear for m=0 and m=1, respectively. We make both analytical and graphical studies of these methods, which give rise to rational functions defined in the extended complex plane. Firstly, we prove that the coefficients of the aforementioned family of iterative processes can be written in terms of the Catalan numbers. Secondly, we make an incursion into its dynamical behavior. In fact, we show that the rational maps related to these methods can be written in terms of the entries of the Catalan triangle. Next we analyze its general convergence, by including some computer plots showing the intricate structure of the Universal Julia sets associated with the methods