181 research outputs found
A numerical and experimental study of a new Savonius wind rotor adaptation based on product design requirements
This paper presents the numerical-experimental study carried out on a new rotor adapted from a Savonius rotor. Aesthetic, ergonomic and functional requirements have been incorporated into it in order to be part of sustainable consumer products. The new rotor consists of a parametric model adaptable to the dimensions and geometry of the products which it will be part of. A set of translation, symmetry, rotation and scaling operations have been applied to the bucket sections of the Savonius rotor by means of transforming the initial cylindrical buckets into topological surfaces with an organic shape. The new modified Savonius rotor and the conventional Savonius with the same Aspect Ratio have been tested in an open jet wind tunnel in order to verify the influence level of product design parameters on rotor performance, in terms of power coefficient, torque coefficient and mechanical power generated. Experimental tests have been carried out for Reynolds values in the range of [3,430·104 and 1,419·105]. A numerical analysis using an incompressible unsteady Reynolds average Navier Stockes model has been validated by means of the experimental results. Experimental and numerical results coincide with a 3.5% error. The behavior of the turbine has been analyzed by varying the angle of rotation for the sections of its buckets. Using a rotation angle of 45 ° the power coefficient values improve by 32% compared to the values obtained using an angle of 0 °. The rotor has been dimensioned for its application in a patented consumer product of small dimensions and requirements of lateral accessibility to its interior. Under these limited conditions the rotor meets the small-scale energy requirements of the product. The new rotor is designed as an aid to the energy consumption of the product in which it is incorporated, maintaining the advantages of a conventional Savonius rotor as self-starting, easy manufacture and maintenance, obtaining at the same time a product that sells better, is more able to integrate into its environment and is customizable for the consumer.This work has been supported by the University of Jaen through the project titled ”Diseño de un bastón ecológico de senderismo generador eólico hidráulico” Project Code (AC20/2015-12) and (R1A7/2017). The authors would like to thank the Mechanical Engineering Departmentat Jaen University for using the wind tunnel to achieve the experimental study
Assessing Smartphone Addiction among Mexican Students: Insights, Implications, and Interventions in the Era of Mobile Learning and Virtual Environments
This study conducted a new adaptation of the short version of the Smartphone Addiction Scale (SAS-SV) for the Mexican population. The scale exhibited excellent internal consistency (α = .88), with one factor explaining 54.8% of the variance. 286 students aged 15 to 35 years of age from central and southeast Mexico revealed a prevalence of 30% excessive users (18% men, 12% women). They used smartphones primarily for communication, social media, entertainment, productivity, and browsing the Internet. No gender differences were found; however, a significant association with age emerged (rho = .221, p < .001). Withdrawal (72.7% women) and tolerance (80.8% men) were common symptoms of addiction, while ignorance of consequences was less frequent (33.3% women, 30.8% men). The prevalence of potential excessive use of smartphones was close to the average identified in the reviewed studies. The results revealed a substantial risk of addiction to smartphones, particularly among men. Finally, the successful adaptation of the scale offers a valuable instrument for future study and clinical evaluation. These findings can guide targeted interventions and educational programs tailored to different groups. Additionally, recognition of common symptoms of addiction allows individuals to identify and address potential problems at an early stage. However, more study is needed to validate the findings and explore additional contributing factors in the Mexican context
Hil‐assessed fast and accurate single‐phase power calculation algorithm for voltage source inverters supplying to high total demand distortion nonlinear loads
The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal
A power calculation algorithm for single-phase droop-operated-inverters considering linear and nonlinear loads HIL-assessed
The active and reactive powers, P and Q, are crucial variables in the parallel operation of single-phase inverters using the droop method, introducing proportional droops in the inverter output frequency and voltage amplitude references. P and Q, or P-Q, are calculated as the product of the inverter output voltage and its orthogonal version with the output current, respectively. However, when sharing nonlinear loads these powers, Pav and Qav, should be averaged by low-pass filters (LPFs) with a very low cut-off frequency to avoid the high distortion induced by these loads. This forces the droop method to operate at a very low dynamic velocity and degrades the system stability. Then, different solutions have been proposed in literature to increase the system velocity, but only considering linear loads. Therefore, this work presents a method to calculate Pav and Qav using second-order generalized integrators (SOGI) to face this problem with nonlinear loads. A double SOGI (DSOGI) approach is applied to filter the nonlinear load current and provide its fundamental component to the inverter, leading to a faster dynamic velocity of the droop-based load sharing capability and improving the stability. The proposed method is shown to be faster than others in the literature when considering nonlinear loads, while smoothly driving the system with low distortion levels. Simulations, hardware-in-loop (HIL) and experimental results are provided to validate this proposal
Efecto de la adición de restos de poda y biochar en las propiedades de una turba parda como sustrato de cultivo
Las turberas realizan la función de sumidero de carbono en los ecosistemas terrestres pero debido a su excesivo uso como combustible o como medio de cultivo se está produciendo la sobreexplotación de este recurso no renovable. En los últimos años se han llevado a cabo diversas investigaciones con el objetivo de encontrar sustratos procedentes de diferentes residuos orgánicos que sean de alta calidad y bajo coste con el fin de disminuir el consumo de turba
Five-Factor Model and alcohol outcomes: Mediating and moderating role 4 of alcohol expectancies
The aim of the present study was to examine the relationship between the Five-Factor Model of personality and alcohol expectancies (AEs) with different alcohol outcomes. The sample was composed of 738 participants (63.7% females). Path and regression analyses were performed to test the mediation and moderation effects. The results indicated that Neuroticism was related to alcohol consumption through Positive Alcohol Expectancies, and that Negative Alcohol Expectancies, but also Positive Alcohol Expectancies, partially mediated the relationship of Neuroticism to alcohol-related problems. In addition, Positive Alcohol Expectancies partially mediated the associations of extraversion and low conscientiousness with weekend Standard Drink Units (SDUs), and they completely mediated the associations of these personality variables with alcohol-related problems. Additional direct paths were found from low agreeableness to weekly SDUs and alcohol-related problems; and from low openness to weekend SDUs. Moderation effects of alcohol expectancies on personality and both alcohol use and alcohol-related problems were also found. The present research contributes new evidence on the influence of the five factors of personality on alcohol outcomes, and the mediation/moderation role of alcohol expectancies. These findings can be useful to develop prevention/intervention programmes.Funding for this study has been provided by research projects 386
PNSD2009-019 from the Spanish Ministry of Health, P1·1B2010- 387
40 and P1·1B2011-47 from Bancaixa-Universitat Jaume I
Supervisión de sistemas mediante el uso de tecnologías de realidad aumentada en el contexto de industria 4.0
Las líneas de investigación aplicada tienen por objetivo generar capacidades de supervisión y explotación de sistemas industriales con el empleo de tecnologías de Realidad Aumentada. Esta línea se integra con la línea de desarrollo de sistemas basados en catálogos aumentados los cuales permiten la visualización de información añadida a partir de la captura de marcadores.Eje: Computación Gráfica, Imágenes y Visualización.Red de Universidades con Carreras en Informátic
New Locality of the endangered Sierra Madre Sparrow (Xenospiza Baileyi) from the State of Durango, Mexico, and recommendations for its conservation
The Sierra Madre Sparrow (Xenospiza baileyi) is an endemic species of Mexico that is threatened with extinction. Its distribution is reported in two areas: One in the Transvolcanic Belt of central Mexico (La Cima) near Mexico City and the other in the Sierra Madre Occidental in northwestern Mexico (Ejido Ojo de Agua El Cazador) near the city of Durango, in the state of Durango. The habitat is the same in these two areas, and consists of sub-alpine grassland that is located in shallow valleys or shallows. In our case, "El Bajío la Cantera" of approximately 55 hectares, is mostly used in rainfed agriculture, protected from livestock grazing with wire fences, which in turn represents protection for remnants of grassland where they are the birds. “El Bajío la Cantera" belongs to Ejido 12 de Mayo, Municipality of San Dimas, Durango, where 28 males were detected singing along a 500 meter transect. This finding represents the population of the healthiest Sierra Madre Sparrow currently known, so it would be necessary to document their population trend over time. This information can help to evaluate and propose the creation of a special protection area for the species that involves joint government actions and ejidatarios tending to conserve the habitat during the reproductive season in order to increase and / or maintain the size of the population.El gorrión serrano (Xenospiza baileyi) es una especie endémica de México y se encuentra en peligro de extinción. Su distribución se reporta en dos áreas: Una en el Cinturón Transvolcánico del centro de México (La Cima) cerca de la Ciudad de México y la otra en la Sierra Madre Occidental en el noroeste de México (Ejido Ojo de Agua El Cazador) cerca de la ciudad de Durango, en el estado de Durango. El hábitat es el mismo en estas dos áreas, y consiste en pastizales amacollados subalpinos que se localizan en valles poco profundos o bajíos. En nuestro caso, “El Bajío la Cantera” de aproximadamente 55 Has de superficie, es usado mayormente en la agricultura de temporal, protegida del pastoreo del ganado con cerco de alambre, que a su vez representa protección para los remanentes de pastizal amacollado donde están las aves. “El Bajío la Cantera” pertenece al Ejido 12 de Mayo, Municipio de San Dimas, Durango, donde se detectaron 28 machos cantando a lo largo de un transecto de 500 metros. Este hallazgo representa la población de Gorrión serrano más saludable actualmente conocida, por lo que sería necesario documentar su tendencia poblacional a través del tiempo. Esta información puede ayudar a evaluar y proponer la creación de un área de protección especial para la especie que involucre acciones conjuntas de gobierno y ejidatarios tendientes a conservar el hábitat durante la época reproductiva para lograr aumentar y/o mantener el tamaño de la población
Supervisión de sistemas mediante el uso de tecnologías de realidad aumentada en el contexto de industria 4.0
Las líneas de investigación aplicada tienen por objetivo generar capacidades de supervisión y explotación de sistemas industriales con el empleo de tecnologías de Realidad Aumentada. Esta línea se integra con la línea de desarrollo de sistemas basados en catálogos aumentados los cuales permiten la visualización de información añadida a partir de la captura de marcadores.Eje: Computación Gráfica, Imágenes y Visualización.Red de Universidades con Carreras en Informátic
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