Influencia de las variaciones de la densidad en la cobertera de los cinturones de pliegues y cabalgamientos: aportación de la modelización analógica en centrifugadora

We present an innovative centrifuge analogue modelling approach to evaluate the influence of density contrast on structure location and vergence affecting thin-skinned compressional settings. Our natural prototype involves a detached foreland basin characterized by a basal ductile evaporitic décollement overlain by a brittle-like cover comprising a set of rock density variations. The experimental programme included gravity spreading and shortening characterized by density contrast up to 0.5 gr/cm3. Density contrast boundaries were designed perpendicular to the shortening except for one case, where it was parallel. Under no horizontal stress conditions, i.e. the tectonically quiescence context, just the centrifuge force (up to almost 900g), the cover depicts a syncline-anticline structure were the inflexion point was localized along the density contrast boundary. Moreover, wavelength and amplitude increased following the density contrast rise. In compression, density contrast boundaries perpendicular to the shortening direction controlled the vergence of the developed structuresSe presenta un estudio basado en la modelización analógica en centrifugadora que analiza la influencia que tienen las variaciones laterales de densidad de las rocas en la localización y vergencia de las estructuras afectadas por una tectónica de piel fina en contextos compresivos. El prototipo natural esta constituido por una cuenca de antepaís cabalgante a favor de un nivel de despegue dúctil sobre el cual se apoya una cobertera frágil caracterizada por variaciones laterales de la densidad. El programa experimental incluye experimentos en ausencia de esfuerzos horizontales y compresivos donde los contrastes de densidad varían por debajo de 0,5 gr/cm3. Los límites entre dominios con diferente densidad son perpendiculares al acortamiento salvo en un caso donde es paralelo. En ausencia de esfuerzos horizontales, aplicando la fuerza centrífuga (hasta 900g) se desarrolla una estructura sinclinal-anticlinal cuyo punto de inflexión coincide con el límite entre diferentes densidades y cuya longitud de onda y amplitud aumentan a medida que aumenta el contraste de densidad. En contextos compresivos, los contrastes de densidad localizados perpendicularmente al acortamiento controlan la vergencia de las estructura

A macroscopic performance analysis of NASA’s northrop grumman RQ-4A

This work was partially funded by the Ministerio de Economia y Competitividad of Spain under Contract TRA2016-77012-R and by EUROCONTROL acting on behalf of the SESAR Joint Undertaking (the SJU) and the European Union as part of Work Package E in the SESAR ProgrammeThis paper presents the process of identification, from a macroscopic point of view, of the Northrop Grumman RQ-4A Global Hawk Remote-Piloted Aircraft System from real, but limited flight information. Performance parameters and operational schemes will be extracted by analyzing available data from two specific science flights flown by the Global Hawk back in 2010. Each phase of the flight, take-off, climb, cruise climb, descent and landing, is analyzed from various points of view: speed profile, altitude, climb/descent ratios and rate of turn. The key performance parameters derived from individual flights will be confirmed by performing a wider statistical validation with additional flight trajectories. Derived data are exploited to validate a simulated RQ-4A vehicle employed in extensive real-time air traffic management simulated integration exercises and to complement the development of a future RQ-4A trajectory predictor.Peer ReviewedPostprint (published version

Real-time simulations to evaluate the RPAS integration in shared airspace

This paper presents the work done during the first year in the WP-E project ERAINT (Evaluation of the RPAS-ATM Interaction in Non-Segregated Airspace) that intends to evaluate by means of human-in-the-loop real-time simulations the interaction between a Remotely Piloted Aircraft System (RPAS) and the Air Traffic Management (ATM) when a Remotely Piloted Aircraft (RPA) is being operated in shared airspace. This interaction will be evaluated from three different perspectives. First, the separation management, its results are presented in this paper. Secondly, during the next year, the contingency management, also including loss of link situations and, lastly, the capacity impact of such operations in the overall ATM system. The used simulation infrastructure allows to simulate realistic exercises from both the RPAS Pilot-in-Command (PiC) and the Air Traffic Controller (ATCo) perspectives. Moreover, it permits to analyze the actual workload of the ATC and to evaluate several support tools and different RPAS levels of automation from the PiC and ATC sides. The simulation results and the usefulness of the support tools are presented for each selected concept of operations.Peer ReviewedPostprint (published version

Inversion of transfer zones in salt-bearing extensional systems: insights from analogue modeling

This work uses sandbox analogue models to analyze the formation and subsequent inversion of a decoupled extensional system comprised of two segmented half-grabens with thick early syn-rift salt. The segmented half grabens strike perpendicular to the direction of extension and subsequent shortening. Rifting created first a basement topography that was infilled by model salt, followed by a second phase of extension and sedimentation, followed afterwards by inversion. During the second phase of extension, syn-rift syncline minibasins developed above the basement extensional system and extended beyond the confines of the fault blocks. Sedimentary downbuilding and extension initiated the migration of model salt to the basement highs, forming salt anticlines, reactive diapirs, and salt walls perpendicular to the direction of extension, except for along the transfer zone where a slightly oblique salt anticline developed. Inversion resulted in decoupled cover and basement thrust systems. Thrusts in the cover system nucleated along squeezed salt structures and along primary welds. New primary welds developed where the cover sequence touched down on basement thrust tips due to uplift, salt extrusion, and syn-contractional downbuilding caused by loading of syn-contractional sedimentation. Model geometries reveal the control imposed by the basement configuration and distribution of salt in the development of a thrust front from the inversion of a salt-bearing extensional system. In 3D, the interaction of salt migrating from adjacent syn-rift basins can modify the expected salt structure geometry, which may in turn influence the location and style of thrust in the cover sequence upon inversion. Results are compared to the northern Lusitanian Basin, offshore Portugal and the Is&agrave;bena area of the South-Central Pyrenees, Spain.</p

A room of the mind: from the studiolo to the metaphysical room.

The aim of this article is to propose an approach to the “space of the mind” through the analysis of successive spaces built with scenographical techniques that can be found in some domestic rooms. Two rooms, conceived and built in Italy, separated from each other by half a millennium, were taken as a case study. These are the studiolo of Federico da Montefeltro and the Stanza Metafísica of Piero Fornasetti. The starting point is the studiolo, a type of private room that has its origins in the Renaissance, and while it has been blurred since then, its specific qualities has been applied to other spaces throughout history. The studiolo was the most intimate room in the house, dedicated to intellectual activity, and it was a representation of the individual. It was a space with the ability to translate the owner into another world—its authentic inner world—through the decoration and objects it contained. Usually, the studioli are lined with wood because of their ability to achieve a sheltered interior. At the beginning of the 15th century, carpenters and artisans developed a way of working this paneling that clad rooms using the intarsia technique. This novel technique, together with the rise and development of the laws of perspective, conquered wooden flat surfaces by turning them into windows to other imaginary worlds that looked out onto the universe of the mind, allowing the penetration of a new fictitious space. One of the most paradigmatic cases of the time, which combines all these qualities, is the pair of studioli commissioned by Federico da Montefeltro in the ducal palaces in Urbino (1473–1476) and Gubbio (1479–1482), made up of embedded wood panels that display an extraordinary collection of objects, and interior and exterior visions that completely transform the original space. Almost five hundred years after the completion of Gubbio’s studiolo, between 1955 and 1958, Piero Fornasetti created the Stanza Metafísica. This is a room capable of adapting to any space, able to grow and shrink, a scenography dedicated to meditation. The 32 wooden panels that form it, treated using a contemporary technique, take us to the same place of the mind, which is completely different from the Gubbio one. Full cabinets are now simply architecture without function, devoid of objects and references: black lines and pure geometry on a white background. The Fornasetti stanza gathers many of the qualities of the Renaissance studiolo and appropriates them, adapting it to the new techniques and conception of space. In conclusion, both examples reveal the existence of both a physical room and another metaphysical room—i.e., a fictitious space contained within a real space, built through technique and perspective. These are scenographies capable of being moved and adapted to disguise any room, transforming it into a space that is inhabited by the mind for an intimate, individual intellectual activity.post-print2775 K

Influence of décollement-cover thickness variations in fold-and-thrust belts: Insights from centrifuge analog modeling

Centrifuge analog modeling incorporating thickness variations of décollement and overlying sedimentary cover is used to study thrust-wedge evolution on salt-detached contractional systems involving tapered sedimentary cover. From simpler, layer-cake to 3D tapered décollement-cover sequences, our models constrain wedge evolution: a more advanced front, where the cover is thicker, promotes differential frontal translation and triggers vertical axis rotation of several hinterland anticlines which appear towards the thinner cover area. In all cases, the décollement level is strongly sheared and tends to migrate laterally toward the thinner cover areas. Models are compared with previous analog models under normal gravity and the natural example of the South Pyrenean Central salient. All in all, we conclude that a 3D tapered décollement-cover basin architecture, as a sole factor, can determine the formation of a thrust salient formed by increasing structural curvature (progressive arc)

Analysis of the initial thermal stabilization and air turbulences effects on Laser Tracker measurements

During the several last years, Laser Trackers have become more common as a measurement tool in the manufacture and assembly of large components such as aircraft wings and ship hulls, as well as for error mapping in coordinate measuring machines and machine tools. Most of these processes cannot be developed in a controlled metrological laboratory but must be implemented directly on a shop floor. Therefore, the process of stabilization of the Laser Tracker has been studied in several experimental tests, and it has been observed that the warm-up time suggested by the manufacturer is not enough. During the first hours of the measurement process two types of thermal errors significantly affect the measurements, causing inaccuracies of between 20 and 80 µm, depending on the equipment used and the positions of the measured points. These thermal errors are systematic and repeatable; therefore they can be estimated and compensated for each measurement system. Because environmental conditions on a shop floor cannot be controlled, once the Laser Tracker is stabilized, the effects of ambient air in measurements have also been studied, focusing on the effect of turbulent flows on the beam path. It has been observed that this turbulence may cause radial distance drifts on the order of micrometers, deflection of the beam trajectory and signal loss

Algorithm to optimize measurement system location in a machine tool verification

Nowadays, machine tool accuracy is a competitive element. To improve it, machine tools are verified and compensate periodically reducing the influence of their geometric errors. As geometric errors have systematic behavior, their influence can be compensated after verification. However, verification itself is influenced by random uncertainty sources that affect verification results. Within all influences on machine tool volumetric verification, laser tracker measurement noise is a random uncertainty source that is not usually considered. However, it should not be ignored and can be reduced through an adequate location. This paper presents an algorithm able to analyze the influence of laser tracker location, taking into consideration its specifications and machine tool characteristics. To do that, the developed algorithm provides a zone around MT to locate the measurement system using the Monte Carlo Method. Moreover, it provides the probability distribution function of laser tracker influence related to LT location zone. Therefore, if MT is used as a traceable measurement system, its uncertainty cannot be smaller than LT location uncertainty

Study on Machine Tool Positioning Uncertainty Due to Volumetric Verification

Volumetric verification is based on the machine tool (MT) kinematic model, along with its geometric errors. Although users often ignore the uncertainty of verification, the use of the MT as a traceable measurement system in the manufacturing process has increased the need for professionals to be aware of it. This paper presents an improvement in the MT kinematic model, introducing in it the influence of verification uncertainty sources. These sources have been classified into four groups: the MT, the measurement system itself, the measurement strategy, and the optimization strategy. As the developed model exhibits non-linear behavior, the Monte Carlo method was used to determine the influence of the measurement system on verification uncertainty using synthetic tests. In this manner, an improved estimation of the MT uncertainty can be obtained. Therefore, if the MT is used as a traceable measurement system, its accuracy should not be higher than the laser tracker (LT) verification influence. It hence shows the importance of LT influence