Modeling and stability analysis of tethered kites at high altitudes

A systematic analysis of the role played by several physical mechanisms in the longitudinal stability of a tethered kite is presented. A simple model, which artificially constrains the pitch motion of the kite and approximates the tether by a massless and rigid bar, is improved progressively to include the kite pitch motion as well as the tether inertia, flexibility, wind load, and elasticity. The models are presented as compact sets of ordinary differential equations without algebraic constraints, which are explicitly eliminated by making an extensive use of Lagrangian mechanics. The contributions of each physical mechanism on kite stability are investigated separately, and a tradeoff between the complexity and computational costs of the models against their accuracy and reliability is carried out. The wind load on the tether is identified as a key effect stabilizing the steady state of the kites. The optimal bridle design and tether length selections to compute the kite ceiling are discussed.This work was supported by Fundación BBVA under the Convocatoria 2015 de Ayudas BBVA a Investigadores y Creadores Culturales grant no. IN[15]_TIC_ING_0313. G. Sánchez-Arriaga was supported by the Ministerio de Economía y Competitividad of Spain (grant no. RYC-2014-15357)Publicad

Track-to-track association methodology for operational surveillance scenarios with radar observations

This paper proposes a novel track-to-track association methodology able to detect and catalogue resident space objects (RSOs) from associations of uncorrelated tracks (UCTs) obtained by radar survey sensors. It is a multi-target multi-sensor algorithm approach able to associate data from surveillance sensors to detect and catalogue objects. The association methodology contains a series of steps, each of which reduces the complexity of the combinational problem. The main focus are real operational environments, in which brute-force approaches are computationally unaffordable. The hypotheses are scored in the measurement space by evaluating a figure of merit based on the residuals of the observations. This allows us to filter out most of the false hypotheses that would be present in brute-force approaches, as well as to distinguish between true and false hypotheses. The suitability of the proposed track-to-track association has been assessed with a simulated scenario representative of a real operational environment, corresponding to 2 weeks of radar survey data obtained by a single survey radar. The distribution and evolution of the hypotheses along the association process is analysed and typical association performance metrics are included. Most of the RSOs are detected and catalogued and only one false positive is obtained. Besides, the rate of false positives is kept low, most of them corresponding to particular cases or objects with high eccentricity or limited observability.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This project has received funding from the “Comunidad de Madrid” under “Ayudas destinadas a la realizacion doctorados industriales” program (project IND2017/TIC7700

Initial orbit determination methods for track-to-track association

The detection and identification of Resident Space Objects (RSOs) from survey tracks requires robust and efficient orbit determination methods for the association of observations of the same RSO. Both Initial Orbit Determination (IOD) and Orbit Determination (OD) methods perform the orbital estimation in which the association of tracks relies. The choice of proper IOD and OD methods is essential for the whole data association, since they are in charge of providing the estimation required to evaluate the figure of merit of the association. In this paper, we review the state of the art and propose a novel method that does not require initialisation, accounts for measurement noise and provides a full estimation (i.e., state vector and covariance) from an arbitrary number of optical observations. To do so, a boundary value problem is formulated to find a pair of ranges leading to a minimum residuals of the observations. The proposed methods are compared against classical alternatives simulated in scenarios representative of the current space debris environment.This project has received funding from the "Comunidad de Madrid" under "Ayudas destinadas a la realización de doctorados industriales" program (project IND2017/TIC7700). Besides, the authors would like to acknowledge the contributions from Alfredo Miguel Antón Sácnchez, Pablo García Sánchez and Adrián Díez Martín from GMV for their support, review and advice

Procedimiento para la prevención de desórdenes musculoesqueléticos: aplicación en trabajos de minería subterránea

The incidence and prevalence of work-related musculoskeletal disorders is currently one of the most important challenges facing the mining sector. This paper proposes a procedure to prevent these diseases, based on the active participation of workers. The procedure was structured in four stages: hazard identification, risk assessment, proposal of improvements, and implementation and follow-up. To support the application of the procedure, a set of ergonomic methods and tools appropriate for mining work were proposed. The main results of the application of the procedure in an underground mine in Peru are shown, demonstrating its practical value, as well as its usefulness in the improvement of working conditions and in the creation of a preventive culture. The proposed procedure is expected to serve as a reference in the prevention of musculoskeletal disorders in mining works.La incidencia y prevalencia de los desórdenes musculoesqueléticos de origen laboral, es en la actualidad uno de los desafíos más importantes que enfrenta el sector minero. En este trabajo se propone un procedimiento para prevenir estas enfermedades, sustentado en la participación activa de los trabajadores. El procedimiento quedó estructurado en cuatro etapas: identificación de peligros, evaluación de riesgo, propuesta de las mejoras e implementación y seguimiento. Para apoyar la aplicación del procedimiento fueron propuestos un conjunto de métodos y herramientas ergonómicas apropiados para los trabajos de minería. Se muestran los principales resultados de la aplicación del procedimiento en una mina subterránea de Perú, evidenciando el valor práctico de este, así como su utilidad en la mejora de las condiciones de trabajo y en la creación de una cultura preventiva. Se espera que el procedimiento propuesto sirva de referencia en la prevención de los desórdenes musculoesqueléticos en trabajos de minería

Covariance determination for improving uncertainty realism in orbit determination and propagation

The reliability of the uncertainty characterization, also known as uncertainty realism, is of the uttermost importance for Space Situational Awareness (SSA) services. Among the many sources of uncertainty in the space environment, the most relevant one is the inherent uncertainty of the dynamic models, which is generally not considered in the batch least-squares Orbit Determination (OD) processes in operational scenarios. A classical approach to account for these sources of uncertainty is the theory of consider parameters. In this approach, a set of uncertain parameters are included in the underlying dynamical model, in such a way that the model uncertainty is represented by the variances of these parameters. However, realistic variances of these consider parameters are not known a priori. This work introduces a methodology to infer the variance of consider parameters based on the observed distribution of the Mahalanobis distance of the orbital differences between predicted and estimated orbits, which theoretically should follow a chi-square distribution under Gaussian assumptions. Empirical Distribution Function statistics such as the Cramer-von-Mises and the Kolmogorov–Smirnov distances are used to determine optimum consider parameter variances. The methodology is presented in this paper and validated in a series of simulated scenarios emulating the complexity of operational applications.This project has received funding from the "Comunidad de Madrid" under "Ayudas destinadas a la realización de doctorados industriales" program (project IND2020/TIC-17539)

A constraint-free flight simulator package for airborne wind energy systems

Proceeding of: 7th International Conference "The Science of Making Torque from Wind" (TORQUE 2018), Milano, 20-22 June, 2018.The LAgrangian Kite SimulAtor (LAKSA) is a freely available software for the dynamic analysis of tethered flying vehicles, such as kites and fixed-wing drones, applied to airborne wind energy generation. This software comprises four simulators. The one, two and four-line simulators, which consider flexible but inelastic tethers, are based on minimal coordinate Lagragian formulations and can be used for the analysis of fly and ground generation systems, kite-based traction systems, and kitesurfing applications, respectively. The configuration of the mechanical system in the fourth simulator can be defined by the user, who can select the number of flying vehicles and the properties of the elastic and flexible tethers linking them. In all the software tools, the kites or tethered fixed-wing drones are represented as rigid bodies and the dynamic equations of the tether-bridle-vehicle systems, together with the user-defined and time-dependent control variables, are solved self-consistently. Academic and research analysis can take advantage of the modularity of the simulators and their inputs and outputs interfaces, which follow a common and user-friendly architecture.This work was supported by the Ministerio de Economía, Industria y Competitividad of Spain and the European Regional Development Fund under the project ENE2015-69937-R (MINECO/FEDER, UE). GSA work is supported by the Ministerio de Economía, Industria y Competitividad of Spain under the Grant RYC-2014-15357. RS is acknowledging the receipt of funding from the European Unions Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 642682 for the ITN project AWESCO and the grant agreement No. 691173 for the Fast Track to Innovation project REACH.Publicad

Early cataloguing of fragments from break-up events

Break-up events represent the dominant source of objects in space catalogues, surpassing half of the overall population. These not so uncommon events include explosions, collisions or anomalous events resulting in fragmentations and their number is estimated to be higher than 630. The early cataloguing of the fragments generated during these events poses a complex challenge for space objects catalogue build-up and maintenance processes. The provision of Space Surveillance and Tracking products and services during the few first days after a break-up event can be crucial to avoid collisions between the fragments and other space objects, particularly in highly congested regimes, such as Low Earth Orbit. In this regard, reducing the time required to accurately estimate the trajectories of the fragments may enable the execution of collision avoidance manoeuvres, in the case of operational space objects with manoeuvre capabilities, and analyse potential collision cascade events, which may endanger the space environment. This paper studies the whole cataloguing process after a break-up event, starting from a catalogue with no fragments from the fragmentation under-analysis, and until a well-established orbit is obtained for all fragments, using a ground-based sensor network. First, the observations enter a multi-sensor multi-target track-to-track association algorithm in charge of grouping observations belonging to the same objects. To resolve the ambiguity, particularly shortly after the event, hypotheses about tracks belonging to the same fragment are generated, scored, pruned, and promoted, only when there is enough confidence, leading to the initialisation of new objects in the catalogue. As soon as the catalogue is populated, a track-to-orbit correlation algorithm is responsible for the correlation of observations and already catalogued orbits. This alleviates the track-to-track association and enables the update of the orbital estimates, required for maintaining the catalogue.This work was conducted during the research stay of A. Pastor in the ESA Space Debris Office at ESOC in Darmstadt. The corresponding author greatly appreciates the warm welcome, interest and support of the whole team. This project has received funding from the ”Comunidad de Madrid” under ”Ayudas destinadas a la realización de doctorados industriales” program (project IND2017/TIC7700).Publicad

Sarcopenia: molecular pathways and potential targets for intervention

Producción CientíficaAging is associated with sarcopenia. The loss of strength results in decreased muscle mass and motor function. This process accelerates the progressive muscle deterioration observed in older adults, favoring the presence of debilitating pathologies. In addition, sarcopenia leads to a decrease in quality of life, significantly affecting self-sufficiency. Altogether, these results in an increase in economic resources from the National Health Systems devoted to mitigating this problem in the elderly, particularly in developed countries. Different etiological determinants are involved in the progression of the disease, including: neurological factors, endocrine alterations, as well as nutritional and lifestyle changes related to the adoption of more sedentary habits. Molecular and cellular mechanisms have not been clearly characterized, resulting in the absence of an effective treatment for sarcopenia. Nevertheless, physical activity seems to be the sole strategy to delay sarcopenia and its symptoms. The present review intends to bring together the data explaining how physical activity modulates at a molecular and cellular level all factors that predispose or favor the progression of this deteriorating pathology.ISABIAL (grant number 190290)Instituto de Salud Carlos III - Fondo Europeo de Desarrollo Regional (CB12/03/30038

Propuesta de implementación de una red interna de gas natural para reducción de costos en el hospital Eleazar Guzmán Barrón

El gas natural se presenta como un combustible sustituto de los combustibles tradicionalmente empleados aun en la ciudad de Chimbote, básicamente por su disponibilidad en red de ductos de distribución, plan tarifario para facturación según el tipo de consumo y las bajas emisiones de gases de efecto invernadero que emite. El gas natural en esta ciudad llega a través de un gasoducto virtual como gas natural licuado. El trabajo de investigación es una propuesta de implementación de una red interna de gas natural en el Hospital Regional Eleazar Guzmán Barrón, es del tipo pre - experimental, de naturaleza descriptiva. El diseño de la investigación pre- experimental se emplea para establecer la relación entre la causa y el efecto de una situación. Dentro de los resultados obtenidos tenemos que se realizó los cálculos con una máxima demanda requerida de 40 Sm3/día, con lo cual pertenece a la categoría tarifaria es la IV. Se determino las características de la estación de regulación y medición para la red interna de gas natural en el Hospital Eleazar Guzmán Barrón, siendo la presión de diseño 6 bar y la presión de suministro de la red de 5 bar, con tubería de acero 2” SCH40, medidor de caudal G40, regulador de presión Staflux 185 DN 2” y una válvula de alivio de 54D de ¾” a 1”. Mientras que la red interna es mediante tubería enterrada de 2” SCH 40 en 4 tramos a los puntos de consumo. Las inversiones previstas son de S/. 484 478,5 lo cual genera un ahorro de 15,01 % equivalente a S/107 184,66 al sustituir el petróleo BD5 por gas natural

Systematic prediction of genes functionally associated with bacterial retrons and classification of the encoded tripartite systems

We thank all members of the NTG laboratory for helpful discussions during the development of this project. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Supplementary Data are available at NAR Online: https://academic.oup.com/nar/article-lookup/doi/10.1093/nar/gkaa1149#supplementary-dataBacterial retrons consist of a reverse transcriptase (RT) and a contiguous non-coding RNA (ncRNA) gene. One third of annotated retrons carry additional open reading frames (ORFs), the contribution and significance of which in retron biology remains to be determined. In this study we developed a computational pipeline for the systematic prediction of genes specifically associated with retron RTs based on a previously reported large dataset representative of the diversity of prokaryotic RTs. We found that retrons generally comprise a tripartite system composed of the ncRNA, the RT and an additional protein or RT-fused domain with diverse enzymatic functions. These retron systems are highly modular, and their components have coevolved to different extents. Based on the additional module, we classified retrons into 13 types, some of which include additional variants. Our findings provide a basis for future studies on the biological function of retrons and for expanding their biotechnological applications.Spanish Ministerio de Ciencia, Innovacion y UniversidadesEuropean Commission BIO2017-82244-PFPU predoctoral fellowship grant from the Ministerio de Economia y Competitividad FPU15/02714FPU predoctoral fellowship grant from the Ministerio de Ciencia, Innovacion y Universidades FPU17/0508