1,957 research outputs found

    The Effect of a Flexible Blade for Load Alleviation in Wind Turbines

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    This article presents the analysis of the performance of a flexible wind turbine blade. The simulation analysis is based on a 3 m span blade prototype. The blade has a flexible surface and a cam mechanism that modifies the aerodynamic profile and adapts the surface to different configurations. The blade surface was built with a flexible fiberglass composite, and the internal mechanism consists of a flexible structure actuated with an eccentric cam. The cam mechanism deforms five sections of the blade, and the airfoil geometry for each section was measured from zero cam displacement to full cam displacement. The measured data were interpolated to obtain the aerodynamic profiles of the five sections to model the flexible blade in the simulation process. The simulation analysis consisted of determining the different aerodynamic coefficients for different deformed surfaces and a range of wind speeds. The aerodynamic coefficients were calculated with the BEM method (QBlade®); as a result, the data performance of the flexible blade was compared for the different deformation configurations. Finally, a decrease of up to approximately 6% in the mean bending moment suggests that the flexible turbine rotor presented in this article can be used to reduce extreme and fatigue loads on wind turbines

    Scale of Estimation and Consumption of Foods in Children: Evaluation of their psychometric properties

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    The strategies to reduce overweight and obesity have not had the expected impact. It is necessary to develop greater knowledge regard food estimation and intake frequency. Therefore, the purpose of this study was to examine the psychometric properties of an instrument aimed at the evaluation of meals (EM) and its intake frequency (IFR) in children. A total of 1,090 9-year-old boys and girls from the South region of Jalisco (Mexico) answered the Scale of Estimation and Consumption of Foods in Children, which consists of two sections: EM and IFR. The exploratory factor analysis carried out with 545 participants derived three factors for each section, which were subsequently corroborated based on two confirmatory factor analyses, one per section, performed with the second half of the sample (n = 545). Both models registered some goodness of fit indexes. The final version of the scale, with 23 items, showed appropriate internal consistency in its both sections: EM (α = .86) and IFR (α = .84). The need to extend the analysis of the psychometric properties of the scale in children from other regions of the country is discussed

    La vid silvestre en México. Actualidades y potencial

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    En ocho capítulos se aborda el estado del arte de la vid silvestre en MéxicoEl estudio de las especies vegetales nativas de México representa un reto que cada día más investigadores mexicanos asumen. Durante muchos años, el apoyo a la investigación pública ha sido mínimo; desde el punto de vista agronómico es insuficiente para avanzar a la velocidad que requiere nuestro país para afrontar problemas de producción y distribución de alimentos. Por esa razón, entre otras, me es grato presentar esta obra que compila parte de los trabajos de la Red de Vid Silvestre patrocinada por el Sistema Nacional de Recursos Fitogenéticos (sinarefi) dependiente de la sagarpa; trabajos apuntalados por investigadores que sin pertenecer a la red han colaborado en el estudio de las plantas del género Vitis. En este libro se muestra el potencial del país para aprovechar el recurso vid, empleado desde antes de la conquista española por nativos mexicanos que conocían sus bondades. Es necesario continuar el avance en el conocimiento de este recurso, por ello el presente libro pretende invitar a toda persona interesada en contribuir con el rescate y conservación de las vides mexicanas. Los autores y editores, así como las instituciones en donde laboramos y aquellas que patrocinan estas investigaciones, esperamos se cumpla este objetivo y que el lector, alumno, profesor, investigador, público en general, disfrute esta lectura y, sobre todo, se interese en el recurso VitisSEP, SINAREFI, UAEME

    Vibration Measurement Using Laser Triangulation for Applications in Wind Turbine Blades

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    The blades in a wind turbine are currently manufactured with flexible and light materials, which make them more susceptible to the effects of vibrations when the wind speed is high enough, causing fatigue damage, affecting the functionality of its structure and aerodynamic efficiency. This work presents a comparison of the modal vibration parameters, applied to a cantilever beam, determined with two experimental methods—the use of accelerometers and a proposed optical non-contact method—based on the principle of laser triangulation and photogrammetry techniques. This technique uses the geometric symmetry of the equidistant displacements along the z axis of the beam to obtain the amplitude data. Parameters such as natural frequency and modal form are obtained by fitting the data to a nonlinear equation with a solution which is an exponential/harmonic equation. Also, analytically, these parameters are determined, and a comparison is made between the experimental methods. The result shows that the relative error of the first-order natural vibration frequency is below 1%. The proposed method is simple, efficient, reliable, and it is also a method that has not been applied to the test of wind turbine blades, so its implementation as this type of wind turbine component is an area of opportunity for the validation of modal vibration parameters in the wind industry. An analysis of results is presented showing benefits of the proposed method and its limitations

    The Research Journey as a Challenge Towards New Trends

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    The academic community of the department of Risaralda, in its permanent interest in evidencing the results of the research processes that are carried out from the Higher Education Institutions and as a product of the VI meeting of researchers of the department of Risaralda held in November 2021 presents its work: “The journey of research as a challenge towards new trends”, which reflects the result of the latest research and advances in different lines of knowledge in Agricultural Sciences, Health Sciences, Social Sciences and Technology and Information Sciences, which seek to solve and meet the demands of the different sectors. This work would not have been possible without the help of each of the teachers, researchers and authors who presented their articles that make up each of the chapters of the book, to them our gratitude for their commitment, dedication and commitment, since their sole purpose is to contribute from the academy and science to scientific and technological development in the search for the solution of problems and thus contribute to transform the reality of our society and communities. We also wish to extend our gratitude to the institutions of the Network that made this publication possible: UTP, UCP, UNAD, UNIREMINGTON; UNISARC, CIAF, Universidad Libre, Uniclaretiana, Fundación Universitaria Comfamiliar and UNIMINUTO, institutions that in one way or another allowed this work to become a reality, which we hope will be of interest to you.Preface............................................................................................................................7 Chapter 1. Technologies and Engineering Towards a humanization in Engineering using soft skills in training in Engineers.............................................................................................................11 Omar Iván Trejos Buriticá1, Luis Eduardo Muñoz Guerrero Innovative materials in construction: review from a bibliometric analysis....................................................................................................................27 Cristian Osorio Gómez, Daniel Aristizábal Torres, Alejandro Alzate Buitrago, Cristhian Camilo Amariles López Bibliometric review of disaster risk management: progress, trends, and challenges.........................................................................................................51 Alejandro Alzate Buitrago, Gloria Milena Molina Vinasco. Incidence of land coverage and geology, in the unstability of lands of the micro-basin of the Combia creek, Pereira, Risaralda....................................73 Alejandro Alzate Buitrago, Daniel Aristizábal Torres. Chapter 2. Arts, Humanities, and Social Sciences Training experience with teachers teaching mathematics using the inquiry methodology ...............................................................................................95 Vivian Libeth Uzuriaga López, Héctor Gerardo Sánchez Bedoya. Interpretation of the multiple representations of the fears associated to the boarding of limited visual patients in the elective I students’ written productions and low vision ...................................................................................113 Eliana Bermúdez Cardona, Ana María Agudelo Guevara, Caterine Villamarín Acosta. The relevance of local knowledge in social sciences............................................131 Alberto Antonio Berón Ospina, Isabel Cristina Castillo Quintero. Basic education students’ conceptions of conflict a view from the peace for the education....................................................................................................143 Astrid Milena Calderón Cárdenas,Carolina Aguirre Arias, Carolina Franco Ossa, Martha Cecilia Gutiérrez Giraldo, Orfa Buitrago. Comprehensive risk prevention in educational settings: an interdisciplinary and socio-educational approach ............................................................................163 Olga María Henao Trujillo, Claudia María López Ortiz. Chapter 3. Natural and Agricultural Sciences Physicochemical characterization of three substrates used in the deep bedding system in swine .......................................................................................175 Juan Manuel Sánchez Rubio, Andrés Felipe Arias Roldan, Jesús Arturo Rincón Sanz, Jaime Andrés Betancourt Vásquez. Periodic solutions in AFM models........................................................................187 Daniel Cortés Zapata, Alexander Gutiérrez Gutiérrez. Phenology in flower and fruit of Rubus glaucus benth. Cv. Thornless in Risaralda: elements for phytosanitary management .........................................199 Shirley Palacios Castro, Andrés Alfonso Patiño Martínez, James Montoya Lerma, Ricardo Flórez, Harry Josué Pérez. Socio-economic and technical characterization of the cultivation of avocado (Persea americana) in Risaralda..............................................................217 Andrés Alfonso Patiño Martínez, Kelly Saudith Castañez Poveda, Eliana Gómez Correa. Biosecurity management in backyard systems in Santa Rosa de Cabal, Risaralda................................................................................................................227 Julia Victoria Arredondo Botero, Jaiver Estiben Ocampo Jaramillo, Juan Sebastián Mera Vallejo, Álvaro de Jesús Aranzazu Hernández. CONTENTS Physical-chemical diagnosis of soils in hillside areas with predominance of Lulo CV. La Selva production system in the department of Risaralda.............241 Adriana Patricia Restrepo Gallón, María Paula Landinez Montes, Jimena Tobón López. Digestibility of three concentrates used in canine feeding....................................271 María Fernanda Mejía Silva, Valentina Noreña Sánchez, Gastón Adolfo Castaño Jiménez. Chapter 4. Economic, Administrative, and Accounting Sciences Financial inclusion in households from socioeconomic strata 1 and 2 in the city of Pereira ..................................................................................................285 Lindy Neth Perea Mosquera, Marlen Isabel Redondo Ramírez, Angélica Viviana Morales. Internal marketing strategies as a competitive advantage for the company Mobilautos SAS de Dosquebradas........................................................................303 Inés Montoya Sánchez, Sandra Patricia Viana Bolaños, Ana María Barrera Rodríguez. Uses of tourist marketing in the tourist sector of the municipality of Belén de Umbría, Risaralda.............................................................................................319 Ana María Barrera Rodríguez, Paola Andrea Echeverri Gutiérrez, María Camila Parra Buitrago, Paola Andrea Martín Muñoz, Angy Paola Ángel Vélez, Luisa Natalia Trejos Ospina. Territorial prospective of Risaralda department (Colombia), based on the SDGS...............................................................................................................333 Juan Guillermo Gil García, Samanta Londoño Velásquez. Chapter 5. Health and Sports Sciences Performance evaluation in times of pandemic. What do medical students think?.......................................................................................................353 Samuel Eduardo Trujillo Henao, Rodolfo A. Cabrales Vega, Germán Alberto Moreno Gómez. The relevance of the therapist’s self and self-reference in the training of psychologists.....................................................................................................371 Maria Paula Marmolejo Lozano, Mireya Ospina Botero. Habits related to oral health which influence lifestyle of elder people in a wellness center for the elderly in Pereira 2020. .............................................387 Isadora Blanco Pérez, Olga Patricia Ramírez Rodríguez, Ángela María Rincón Hurtado. Analysis of the suicide trend in the Coffee Region in Colombia during the years 2012-2018 ..............................................................................................405 Germán Alberto Moreno Gómez, Jennifer Nessim Salazar, Jairo Franco Londoño, Juan Carlos Medina Osorio. Hind limb long bone fractures in canines and felines...........................................419 María Camila Cruz Vélez, Valentina Herrera Morales, Alba Nydia Restrepo Jiménez, Lina Marcela Palomino, Gabriel Rodolfo Izquierdo Bravo. Prevalence of overweight and obesity in children in the rural and urban area of Risaralda....................................................................................................439 Angela María Álvarez López, Angela Liceth Pérez Rendón, Alejandro Gómez Rodas, Luis Enrique Isaza Velásquez. Chapter 6. Architecture, Design and Advertising The artisan crafts of Risaralda, characteristics, importance, and risks within the Colombian Coffee Cultural Landscape, CCCL....................................457 Yaffa Nahir Ivette Gómez Barrera, Javier Alfonso López Morales

    Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

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    Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

    Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

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    The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E2^{-2} shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E2^{-2} be able to explain the observations

    Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

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    In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

    Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

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    The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle
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