Hydrokinetic turbine power production depends on the interaction between the rotor and water. Therefore, an optimum geometry of the rotor must be designed and constructed to capture the maximum water energy and convert it into a usable energy. The steps involved in the design and numerical simulation of a small horizontal axis hydrokinetic turbine rotor are presented based on the same incompressible flow techniques used for designing wind turbines. Three blades of a 1 Hp (746 W) prototype hydrokinetic turbine were designed for a water velocity of 1.5 m/s with a tip speed ratio of 6.325, an angle of attack of 5• and 0 • as the pitch angle; in order to obtain the maximum power coefficient of the turbine. This coefficient was 0.4382, near the Betz limit. S822 airfoil was used to generate the coordinates of the blade. CFD simulation was carried out using Ansys CFX to estimate the performance of the blade design. Furthermore, FEM was successfully used for stress calculations on turbine blades under the influence of centrifugal and hydrodynamic loading.The designed hydrokinetic turbine can be used for pico hydro generation in rural communities non-connected to electricity services through the national interconnected electric system, due to its simple structure, and low cost of initial investment. Additionally, it can be locally manufactured, the environmental impact is negligible, since large dams are not involved, and the schemes can be managed and maintained by the consumer.
En muchas situaciones, la teoría recomienda un determinado modelo predictivo para una serie de tiempo financiera. Sin embargo, algunos comportamientos de estas series hacen que el modelo no sea apropiado. Una de las razones para ello puede ser la no linealidad de esos comportamientos. Se propone tratar estas series con modelos TAR (modelo autorregresivo por tramos); dichos modelos se definen por una variable umbral, por lo que en general resulta ser un modelo temporal no lineal. Un modelo de este tipo se formula como una serie temporal con su rezago como variable umbral, donde d es un entero positivo denominado retardo umbral. La variable umbral se desconoce en la práctica, y es importante saber cómo determinarla; en este artículo se explica cómo. Los modelos TAR se ilustran haciendo una modelación del PIB de España. Palabras clave: Modelos TAR, variables umbrales, regímenes. Clasificación JEL: C23, C51 Abstract: In some situations, theoreticians recommend a given predictive model for a series of financial time. However, some inappropriate behaviors in given series make such a model unsuitable. One of the reasons for this can be the non-linearity of those behaviors. A proposed model to treat these series is the TAR model (threshold autoregressive). TAR models are determined by a variable called threshold for which it mainly results to be a temporal nonlinear model. A TAR model expresses itself as a temporal series, with a lagged as a threshold variable, where d is an entire positive called retard threshold. In practice, the threshold variable is unknown, due to which an important question is how to determine it; an answer to this question is given in this paper. TAR models are illustrated by modeling Spain's Gross Domestic Product. Key words: TAR model, threshold variable, regimes.. JEL: C23, C51 Résumé: Dans quelques situations, les théoriciens recommandent un modèle prédictif donné pour une série de temps financier. Cependant, quelques comportements inadéquats des séries données rendent un tel modèle peu convenable. Une raison de ceci est qu'il ne tient pas compte des comportements non linéaires. Un modèle proposé pour traiter ces séries est le modèle TAR (seuil auto-régressif). Des modèles TAR sont déterminés par un variable seuil pour lequel il résulte principalement un modèle non-linéaire temporel. Un modèle TAR s'exprime comme série temporelle , avec un traîné comme un variable de seuil, où d est un positif entier appelé seuil de retard. Dans la pratique, la variable de seuil est inconnu, alors qu'une question importante est comment le déterminer ; une réponse à cette question est donnée en cet article. Des modèles TAR sont illustrés en modelant le produit intérieur brut de l'Espagne. Mots Clés: modèle TAR , seuil variable, regimes.
Se presenta el caso de una Joven de 14 años con adenomegalias cervicales bilaterales masivas, con diagnóstico clínico de linfoma y cuyo estudio anatomopatológico demostró los hallazgos morfológicos de la histiocitosis sinusal con linfadenopatía masiva. Esta entidad debe tenerse en cuenta en todo diagnóstico diferencial de adenomegalias masivas en niños o pacientes Jóvenes, pues el curso clínico y el pronóstico en general son benignos.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.