Improvements in Pain, Well-being, Arterial Pressure, and Lower Limb Volume Following Andullation Therapy in Healthy and Unhealthy Humans

Our aim was to test the effects of Andullation therapy on pain threshold, pain perception, feeling of well-being, arterial pressure, and leg volume in healthy and unhealthy patients. We used a multidirectional vibration (frequency range: 5–40 Hz; peak-to-peak amplitude: 2–8 mm; acceleration: 0.4–2 m/s 2 ) in an undulatory way through the surface of the body when the patient was in contact with a mattress (“andullation”). The vibes traveled from the heel to the head in a random fashion while the participants (N = 50) were lying on the mattress. We measured the pain threshold using an algometer; pain perception and well-being through a visual analog scale (VAS); arterial pressure with an electronic sphygmomanometer; and leg volume with Kuhnke’s technique. Measurements were made just before the first andullation session and after the fifth andullation session. Every participant received andullation sessions of 30 min a day for 5 consecutive days. The patients’ pain threshold significantly (P <.001) increased by 34.48% and 25.79% in the lumbar and trapezius zones, respectively, after 5 sessions of therapy. The subjective perception of pain decreased by 52.3% and the feeling of well-being increased by 45.1%. The systolic and diastolic pressures significantly (P <.001) decreased by 6.44 and 4.68 mm Hg on average, respectively. Leg volume significantly decreased (P <.01) by 64.39 mL after the fifth andullation session. Despite not including a control group in our study, the andullation intervention showed an improvement in pain, well-being, arterial pressure, and lower limb volume in the studied population.Fundación para la Investigación de la Universidad de Sevilla FIUSHome Health Products HH

Deep reinforcement learning for attacking wireless sensor networks

Recent advances in Deep Reinforcement Learning allow solving increasingly complex problems. In this work, we show how current defense mechanisms in Wireless Sensor Networks are vulnerable to attacks that use these advances. We use a Deep Reinforcement Learning attacker architecture that allows having one or more attacking agents that can learn to attack using only partial observations. Then, we subject our architecture to a test-bench consisting of two defense mechanisms against a distributed spectrum sensing attack and a backoff attack. Our simulations show that our attacker learns to exploit these systems without having a priori information about the defense mechanism used nor its concrete parameters. Since our attacker requires minimal hyper-parameter tuning, scales with the number of attackers, and learns only by interacting with the defense mechanism, it poses a significant threat to current defense procedures

Formación inicial y conocimiento didáctico del contenido en los profesores de educación física de secundaria de la ciudad de Badajoz

La formación inicial de los profesores de educación física es puesta en entredicho por los propios profesionales dedicados a la enseñanza. Son muchas las carencias con las que se encuentran al incorporarse a un centro educativo, algunas derivadas del propio centro y otras derivadas de la formación inicial recibida en su etapa universitaria. Las prácticas docentes, la didáctica, el conocimiento didáctico del contenido, los propios alumnos, sus intereses y motivaciones, las instalaciones y los recursos son algunas de las lagunas que encuentran los docentes de secundaria en los centros educativos al desarrollar su labor docente. Los docentes del área de educación física de secundaria reclaman de la universidad mayor formación didáctica, más y mejores prácticas docentes de los contenidos propios del área. Reclaman así mismo mayor conexión y adecuación entre el centro de formación inicial y el centro educativo donde ejercen su desarrollo profesional

Influence of Reynolds number on theoretical models for trailing vortices

We conduct direct numerical simulations for a NACA0012 airfoil at Reynolds numbers (Re) ranging from 300 to 7000 to determine the wake behavior behind this wing profile. We characterize the structure of the wing-tip vortex, finding a reasonable agreement with experimental results at Re=7000. In addition, we model the trailing vortex theoretically, thus obtaining the parameters for Batchelor’s and Moore and Saffman’s models. We compare the results of the best fitting for the axial vorticity and the azimuthal velocity, finding only small discrepancies. The main contribution of this research work is to study the evolution of these theoretical parameters as function of the Reynolds number. We observe that the wake becomes unstable at Re ≈1200, in agreement with previous results. These instabilities in the wake behind the wing produce a change in the trend of theoretical parameters (keywords: vortex dynamics, trailing vortices, theoretical models).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Modeling the external flow of a novel HorseShoe receiver and the evaluation of thermal performance

The linear receiver of a Parabolic Trough Collector is the most critical element in the entire system. The Universal Vacuum Air Collector concept is the most extended type of receiver in both experimental and industrial facilities. Besides their considerable cost, their efficiency usually drops as operation time passes. This is mainly due to a partial loss of vacuum in the evacuated annulus between the absorber and the glass cover. An alternative design called HorseShoe receiver is proposed in this work, whose main goal is to maintain the thermal performance throughout its entire lifespan. This innovative receiver is indicated for low-to-medium temperature ranges, which is particularly suitable for solar heat for industrial processes. It consists of a horseshoe-like cavity absorber having its upper border insulated. In addition, two main advantages can be taken by using two symmetric lenses as glass cover: reconcentrate solar radiation into the cavity (improvement of the intercept factor) and protect stratification conditions (reduction of thermal losses). A transient numerical model with customized boundary conditions has been implemented to evaluate both thermal performance and temperature difference in the absorber domain, which is critical for the thermal stress conditions. For that purpose and as a key contribution, not only the Heat Transfer Fluid (HTF) temperature but also the heat transfer coefficient in the duct are set. In particular, HTF temperature ranges from 80 °C to 220 °C and the inner heat transfer coefficient from 600 W/(mK) to 1800 W/(mK). Results show that numerical thermal performance is above 96%, which is mainly due to the reduction of thermal radiation losses, where the absorber active surface emittance is . (...)Second (corresponding) author J.J. Serrano-Aguilera acknowledges the support provided by Junta de Andalucía (Government of Andalusia) and Universidad de Málaga for the source of funding for the HERTERSOL project (UMA18-FEDERJA-195), as well as to Ministerio de Ciencia, Innovación Universidades (Spain) by means of the postdoc position: Ref No. FJCI-2017-32403 (Juan de la Cierva-Formación Postdoc Grant). Third author acknowledges the support of Universidad de Málaga, Spain through the Project WALICON, 2021. Authors also acknowledge funding for open access charge: Universidad de Málaga / CBUA

Landing craft - diseño de una embarcación landing craft con propulsión alternativa para dar servicio a buques de tipo explorer

Este proyecto trata el desarrollo de una embarcación landing craft impulsada mediante propulsión eléctrica con el objetivo de poder dar servicio a buques de tipo megayate o de tipo explorer, a modo de embarcación tender. la función de este innovador modelo de tender es servir de elemento para el desembarco de unidades terrestres embarcadas en el buque nodriza para así poder explorar lugares inhóspitos e incluso deshabitados

Parabolic trough collectors. Fundamentals of heat transfer applied to solar thermal energy.

Solar thermal energy has undergone major development in recent years. The most widely used technologies are central receiver solar towers and parabolic trough collectors (PTC)[1]. The latter technology has great advantages due to its higher optical and thermal efficiency, but, despite being a well-proven technique, it presents certain problems inherent to the manufacturing and durability of some critical elements in the system. They are generally composed of an absorber tube surrounded by a glass cover and in the intermediate space, a vacuum is created to minimize thermal losses by convection[2]. The absorber tube is located at the focal line of a parabolic mirror that concentrates sun’s rays. To predict the thermal behavior of this type of system, ray-tracing techniques are used to determine the thermal load and accurate correlations are also needed to calculate the convective heat transfer. Also, the original design shows some problems such as the selective coating applied on the absorber surface, whose thermal performance decays with time. Besides, the metal-glass welding are also a significant weak spot, which due to the thermal expansion can cause the partial or total loss of the vacuum in the aforementioned annulus. In this work we present the results of the modeling of this type of systems in different working configurations, as well as a new design proposal to improve the thermal transfer in this type of systems.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Global stability map of the flow in a horizontal concentric cylinder forced by natural convection.

There are a large number of studies in the literature on natural convection in the annulus between horizontal concentric cylinders. However, not many publications dealing with global stability analysis in this kind of flow have been published. For a fixed diameter ratio L/Di = (Ro − Ri)/2Ri, being Ri and Ro the inner and outer cylinder radii respectively, and assuming Boussinesq approximation, the solution only depends on Prandtl (P r ≡ ν/α) and Rayleigh (Ra ≡ g β L3 (Ti − To)/(ν α)) numbers. A spectral collocation code has been developed to solve the problem by means of Chebyshev and Fourier differentiation matrices for L/Di = 0.8 and it has been validated with classical experimental results. Steady solutions have been sought within the range P r ∈ [1e−2, 1] and Ra ∈ [1e-2, 5e6]. As a result, a steady solution Pr-Ra map (consisting of 149 x 75 points) has been traced, where the different families of similar solutions found are detailed, mainly characterized by presenting single or multiple plumes. In addition, two main double-solution regions have been found

Experimental observations of trailing vortices at high Reynolds numbers

Experimental techniques applied to the study of wingtip vortices are of great interest for the Fluid Mechanics Community. The available experimental techniques to obtain new insights into trailing vortices, focus on quantitative methods, e.g. Particle Image Velocimetry (PIV)1,2. In fact, this technique requires high costs associated not only to equipments but also to image processing that is a complex, and time consuming task. A novel, easier, faster and cheaper experimental procedure is presented in this research work to compute experimentally the vortex structure in comparison to a theoretical model. Different theoretical models have described the velocity field for every cross section along the axial coordinate, once the vortex was created at the wing tip. These models depend on several parameters and provide the axial evolution of the velocity field. We used in this study a q-vortex or Batchelor’s3 model, based only on two free parameters: swirl value, q, and the virtual origin in the axial coordinate, z0. These parameters have been processed with the experimental trailing vortex formed by a NACA0012 aerofoil over a Reynolds number range of 105. The experimental setup consists of one smoke wire device together with a laser beam, and a digital camera installed in a subsonic wind tunnel. A smoke segment was generated upstream the model, but near the wing edge. This line followed the main stream passing through the wing tip. Lift forces produced the characteristic vortex pattern, highlighted by the swirling smoke segment, and whose topological structure was recorded by a digital camera. Several sections at different axial distances from the wing edge have been analyzed. The integration of the velocity field in the theoretical model allowed us to know two theoretical parameters in order to obtain similar experimental streaklines at a given axial position, as shown in figure 1. The experimental results using this procedure were in agreement with those found in the literature1.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been supported by the Grant Proyecto de Excelencia nº TEP-7776