Motor commitment depending on the type of support musical dance

Este trabajo de investigación se ha desarrollado en la clase de técnica de danza clásica de un Conservatorio Superior de Danza, un entorno donde la disciplina, rigurosidad y meticulosidad conviven con la creatividad, la expresión y la sensibilidad. El objetivo principal del estudio es analizar las principales diferencias metodológicas, didácticas y pedagógicas, mediante una metodología de investigación mixta, entre la clase impartida con música grabada (CD) y la clase con el profesor pianista acompañante de danza dado que la labor de éste último sigue haciéndose necesaria a pesar de los medios digitales actuales. Se analizó mediante grabación en vídeo, hoja de observaciones y cuestionarios dos clases en las que la única diferencia fue el soporte musical. Se encontraron diferencias significativas entre ambas sesiones, como por ejemplo una media de 38 segundos para la búsqueda de la música necesaria para cada variación con el CD frente a los seis segundos registrados en la sesión con pianista o un mayor número de desplazamientos hacia la fuente de sonido por parte de la profesora en el caso del CD además de aspectos motivacionales y emocionales diferenciados, resultando más eficaz y productivo el uso de la música en vivo frente a la música grabad

Analysis of Metallic Space-Time Gratings using Lorentz Transformations

This paper presents an analytical framework for the study of scattering and diffraction phenomena in spacetime-modulated metallic gratings. Using a Lorentz transformation, it is shown that a particular class of spacetime-modulated gratings behave effectively as moving media. We take advantage of this property to derive a closed analytical solution for the wave scattering problem. In particular, using our formalism it is possible to avoid spacetime Floquet-Bloch expansions, as the solution of the problem in the original laboratory frame (grating parameters are periodic in space and time) is directly linked to a co-moving frame where the metallic grating is time-invariant (grating parameters are periodic only in space). In this way, we identify a fundamental connection between moving metallic gratings and spacetime-modulated metamaterials, and exploit this link to study the nonreciprocal response of the structure. Some limitations and difficulties of the alternative nonrelativistic Galilean approach are discussed and the benefits of the Lorentz approach are highlighted. Finally, some analytical results are presented in order to validate the formalism. The results include scenarios involving TM(p) and TE(s) normal and oblique incidence, even beyond the onset of the diffraction regime. Furthermore, we show how the synthetic Fresnel drag can tailor the Goos-H\"anchen effect and create a specular point shifted towards the direction of the synthetic motion, independent of the sign of the incidence angle.Comment: Published in Physical Review Applied, 20, 014063, 202

Analysis, Validation and Optimization of the Multi-Stage Sequential Wiredrawing Process of EN AW-1370 Aluminium

For the wiredrawing of aluminium, the initial wire rod is obtained by continuous inverted casting. The raw geometry is industrially processed in a linear multi-step wiredrawing sequence to obtain a wire that is commonly used for the manufacture of electrical conductors. In the present work a complete study of the material has been made. The experimental procedure consisted in the realization of a sequence of section reduction stages in the laboratory, a sequence designed following the technological criteria recommended by the manufacturer of the drawing machine in which the industrial process will be implemented. From the specimens corresponding to each reduction step, it has been possible to know the evolution of the main mechanical properties when this pure aluminium is processed by wiredrawing. This information has led to establish the hardening law by which it is possible characterize the plastic behaviour of this pure metal when it is transformed by this specific sequential process of cold forming. The strain hardening law has been implemented in a numerical simulation software application and the experimental setup has been simulated for its validation. Finally, the classic analytical solution founded in the “slab method” has been applied for the design of a proposal for the optimization of the industrial wiredrawing process

Use of the support vector machine (SVM) algorithm to predict geometrical accuracy in the manufacture of molds via single point incremental forming (SPIF) using aluminized steel sheets

In the present work, the use of the support vector machine (SVM) algorithm is proposed to generate models that allow predicting the geometrical accuracy of molds manufactured via single point incremental forming (SPIF) using aluminized steel sheets DX51D AS120 B CO. For this purpose, 27 molds were manufactured, using the dummy technique, and employing different process parameters (tool diameter, spindle speed, feed rate, step size) and toolpath strategies (contour-parallel, spiral, radial). The molds manufactured were geometrically characterized by means of a coordinate measuring machine: the transverse profile of each mold was measured and compared with the expected theoretical profile. Three geometrical values were extracted from this comparison: the area between the two profiles, the moment of inertia of this area with respect to the Y-axis and the difference in height between the two profiles at the mid-point of the mold. The geometrical accuracy of the mold increases if these values decrease. The model that achieved the best results is the one associated with the area between the theoretical and real profiles (correctly classified instances = 90%; kappa statistic = 0.8). This model was generated using the LibSVM (linear kernel) algorithm and evaluating only three of the five parameters (strategy, tool diameter and step size). In addition, process maps were drawn up to show briefly which values generate higher geometrical accuracy in the molds: contour-parallel strategy, tool diameter equal to 12 mm and small step size values

The European Union can afford greater ambition in the conservation of its threatened plants

The importance of Natura 2000 network for the conservation of natural habitats, wild flora and fauna at European level is undeniable. However, it may not have reached its full potential since the loss of biodiversity continues to increase year on year. Further on, a third of the plant species listed in the Habitats Directive to guide the declaration of European Union Natura 2000 network of protected areas is not threatened and there is broad agreement on the need to review and update the species list. Here, the effectiveness of Natura 2000 in the conservation of Spanish bryophytes and vascular plants included in the Habitats Directive Annex II is analysed and compared with the one offered to the species included in the Spanish Red Lists. Results show a remarkable coverage of Natura 2000 over the distribution areas of threatened species, thus providing an umbrella effect on these taxa. It confirms that the number of plant species in the Habitats Directive could be significantly extended without altering the current configuration of the network. This would allow the incorporation of scientific advances produced since the Habitats Directive was approved almost 30 years ago, and will contribute to the goals of the new European Biodiversity Strategy for 2030, such as to consider impacts caused by alien species, land use or climate changesThe Spanish Ministry of Science, Innovation and Universities supported J.C.M.S. through the Bioregions 2.0 project (CGL2017-86926-P

Tiempo de compromiso motor según el soporte musical en danza

This research has been developed in the class of classical dance technique Conservatory of Dance, an environment where discipline, rigor and meticulousness coexist with creativity, expression and sensitivity. The main objective of the study is to analyze the methodological, didactic and pedagogical differences, using a methodology of joint research between the given class with recorded music (CD) and class with teacher accompanist dance since the work of the latter continues necessitating despite today's digital media.Two classes in which the only difference was the music stand was analyzed by video recording, observation sheets and questionnaires. significant differences between the two sessions, such as an average of 38 seconds to search for the needed music for each variation with CD versus six seconds recorded in the session with pianist or found greater number of journeys to the sound source by the teacher in the case of CD in addition to motivational aspects, and emotional differentiated and methodological proving more effective and productive use of live music versus recorded music.Este trabajo de investigación se ha desarrollado en la clase de técnica de danza clásica de un Conservatorio Superior de Danza, un entorno donde la disciplina, rigurosidad y meticulosidad conviven con la creatividad, la expresión y la sensibilidad. El objetivo principal del estudio es analizar las principales diferencias metodológicas, didácticas y pedagógicas, mediante una metodología de investigación mixta, entre la clase impartida con música grabada (CD) y la clase con el profesor pianista acompañante de danza dado que la labor de éste último sigue haciéndose necesaria a pesar de los medios digitales actuales. Se analizó mediante grabación en vídeo, hoja de observaciones y cuestionarios dos clases en las que la única diferencia fue el soporte musical. Se encontraron diferencias significativas entre ambas sesiones, como por ejemplo una media de 38 segundos para la búsqueda de la música necesaria para cada variación con el CD frente a los seis segundos registrados en la sesión con pianista o un mayor número de desplazamientos hacia la fuente de sonido por parte de la profesora en el caso del CD además de aspectos motivacionales y emocionales diferenciados, resultando más eficaz y productivo el uso de la música en vivo frente a la música grabad

Experimental Study for the Stripping of PTFE Coatings on Al-Mg Substrates Using Dry Abrasive Materials

Polytetrafluoroethylene (PTFE) coatings are used in many applications and processing industries. With their use, they wear out and lose properties and must be replaced by new ones if the cost of the element so advises. There are different stripping techniques, but almost all of them are very difficult and require strict environmental controls. It is a challenge to approach the process through efficient and more sustainable techniques. In the present work, we have studied the stripping of PTFE coatings by projection with abrasives (1 step) as an alternative to carbonization + sandblasting procedures (2 steps). For this purpose, different types of abrasives have been selected: brown corundum, white corundum, glass microspheres, plastic particles, and a walnut shell. The tests were performed at pressures from 0.4 to 0.6 MPa on PTFE-coated aluminium substrates of EN AW-5182 H111 alloy. Stripping rates, surface roughness, and substrate hardness have been studied. Scanning electron microscopy (SEM) images of sandblasted specimens have also been obtained. All abrasives improved mechanical and surface properties in one-step vs. two-step processes. The abrasives of plastic and glass microspheres are the most appropriate for the one-step process, which increases the hardness and roughness level Ra in the substrate. Corundum abrasives enable the highest stripping rates

Use of Data Mining Techniques for the Prediction of Surface Roughness of Printed Parts in Polylactic Acid (PLA) by Fused Deposition Modeling (FDM): A Practical Application in Frame Glasses Manufacturing

In the present work, ten data mining algorithms have been used to generate models capable of predicting the surface roughness of parts printed on polylactic acid (PLA) by using fused deposition modeling (FDM). The models have been trained using experimental data measured on 27 horizontal (XY) and 27 vertical (XZ) specimens, printed using different values for the parameters studied (layer height, extrusion temperature, print speed, print acceleration and flow). The models generated by multilayer perceptron (MLP) and logistic model trees (LMT) have obtained the best results in a cross-validation. Although it does not obtain such optimal results, the J48 algorithm (C4.5) allows the generation of models in the form of a decision tree. These trees permit to determine which print parameters have an influence on the surface roughness. For XY specimens, the surface roughness measured in the direction parallel to the extrusion path (Ra,0,XY ) depends on the flow, the print temperature and the layer height; in the direction perpendicular to the extrusion path, the surface roughness (Ra,90,XY) depends only on the flow. For XZ specimens, the surface roughness measured in the direction parallel to the extrusion path (Ra,0,XZ) depends only on the print speed; in the direction perpendicular to the extrusion path (Ra,90,XZ), it depends on the layer height and the extrusion temperature. According to the study carried out, the most suitable set up provides values of Ra,0,XY, Ra,90,XY, Ra,0,XZ and Ra,90,XZ equal to 0.46, 1.18, 0.45 and 11.54, respectively. A practical application of this work is the manufacture of PLA frame glasses using FDM

Los carnívoros del yacimiento pleistoceno de Cueva del Búho (Segovia, España) y sus huellas de actividad

This paper deals with the carnivores from Cueva del Búho (Segovia, Spain) identifying five species (Croeuta eroeuta spelaea, Meles meles, Canis lupus, Vulpes vulpes and, Lynx spelaea). Living traces of hyena are decribed: coprolites, bone surface modifications and body parts representation. It is deduced that this site has been originated in a den of Croeuta croeuta spelaea.Este trabajo estudia los carnívoros de Cueva del Búho (Segovia, España) identificando cinco especies (Croeuta croeuta spelaea, Meles meles, Canis lupus, Vulpes vulpes y Lynx spelaea). Se describen huellas de actividad de hiena: coprolitos, marcas en la superficie de huesos y representación de las distintas partes del esqueleto. Se deduce que el yacimiento se ha originado en una madriguera de Crocuta croeuta spelaea

Stripping of PFA Fluoropolymer Coatings Using a Nd:YAG Laser (Q-Switch) and an Yb Fiber Laser (CW)

Fluoropolymers such as PFA are used as coatings for the protection of metal substrates due to their high chemical inertia and non-stick properties. These are “wear and tear” coatings and they degrade, at which point they should be removed for a new application. The removal of these types of coating by laser is of interest due to the process’s flexibility, precision, ease of automation, and environmental sustainability. The efficiency of the procedure was shown with the use of a source in a pulsed Nd:YAG and a source in continuous mode of fiber (Yb). The rates of stripping (cm2/min) and fluence (J/cm2) were analyzed and related to the power of the laser sources. Variations of the substrate after stripping were studied: roughness and hardness. The properties of the coating, thickness, roughness, water sliding angle, and microhardness were also evaluated. It was concluded that the laser in continuous mode was more efficient than the pulsed laser; laser removal of fluoropolymers has a strong relationship with reflectivity, and the mechanical and surface properties of the substrate after stripping remained virtually unchanged