Long-range forces in controlled systems

This thesis investigates new phenomena due to long-range forces and their effects on different multi-DOFs systems. In particular the systems considered are metamaterials, i.e. materials with long-range connections. The long-range connections characterizing metamaterials are part of the more general framework of non-local elasticity. In the theory of non-local elasticity, the connections between non-adjacent particles can assume different configurations, namely one-to-all, all-to-all, all-to-all-limited, random-sparse and all-to-all-twin. In this study three aspects of the long-range interactions are investigated, and two models of non-local elasticity are considered: all-to-all and random-sparse. The first topic considers an all-to-all connections topology and formalizes the mathematical models to study wave propagation in long-range 1D metamaterials. Closed forms of the dispersion equation are disclosed, and a propagation map synthesizes the properties of these materials which unveil wave-stopping, negative group velocity, instability and non-local effects. This investigation defines how long-range interactions in elastic metamaterials can produce a variety of new effects in wave propagation. The second one considers an all-to-all connections topology and aims to define an optimal design of the long-range actions in terms of spatial and intensity distribution to obtain a passive control of the propagation behavior which may produces exotic effects. A phenomenon of frequency filtering in a confined region of a 1D metamaterial is obtained and the optimization process guarantees this is the best obtainable result for a specific set of control parameters. The third one considers a random-sparse connections topology and provides a new definition of long-range force, based on the concept of small-world network. The small-world model, born in the field of social networks, is suitably applied to a regular lattice by the introduction of additional, randomly selected, elastic connections between different points. These connections modify the waves propagation within the structure and the system exhibits a much higher propagation speed and synchronization. This result is one of the remarkable characteristics of the defined long-range connections topology that can be applied to metamaterials as well as other multi-DOFs systems. Qualitative experimental results are presented, and a preliminary set-up is illustrated. To summarize, this thesis highlights non-local elastic structures which display unusual propagation behaviors; moreover, it proposes a control approach that produces a frequency filtering material and shows the fast propagation of energy within a random-sparse connected material

Long-range Acoustic Interactions in Insect Swarms: An Adaptive Gravity Model

The collective motion of groups of animals emerges from the net effect of the interactions between individual members of the group. In many cases, such as birds, fish, or ungulates, these interactions are mediated by sensory stimuli that predominantly arise from nearby neighbors. But not all stimuli in animal groups are short range. Here, we consider mating swarms of midges, which interact primarily via long-range acoustic stimuli. We exploit the similarity in form between the decay of acoustic and gravitational sources to build a model for swarm behavior. By accounting for the adaptive nature of the midges' acoustic sensing, we show that our "adaptive gravity" model makes mean-field predictions that agree well with experimental observations of laboratory swarms. Our results highlight the role of sensory mechanisms and interaction range in collective animal behavior. The adaptive interactions that we present here open a new class of equations of motion, which may appear in other biological contexts.Comment: 25 pages, 15 figure

Dynamic modelling and real-time monitoring of intelligent wells

Intelligent Wells (I-Wells) are the wells equipped with in-well Flow Control Devices (FCDs) and sensors. I-Wells offer a wide range of flow control and monitoring options, with the latter often being subject to how well the information is derived from the measured, raw data. Pressure or temperature are the measurements most commonly taken and requiring interpretation in I-Wells. This work develops innovative methods for modelling and monitoring of dynamic, transient flow in I-Wells. The topics cover: i. I-well clean-up modelling and analysis; ii. Integrated Pressure and Temperature Transient Analysis (PTTA) in wells; and iii. Pressure Transient Analysis (PTA) in I-Wells. This study starts with addressing the challenging clean-up process in I-Wells. A dynamic, coupled wellbore-reservoir modeling workflow is developed that simulates the whole process from fluid invasion to the flow back period. This is followed by investigating the role of different types of FCDs, e.g. autonomous and passive FCDs, well geometries etc. on the cleanup efficiency. General recommendations to facilitate the clean-up in I-Wells are further provided. This study continues with a novel methodology integrating mature PTA solutions with the relatively new Temperature Transient Analysis (TTA) ones for various applications such as reservoir characterization, flow rate allocation and completion monitoring. Several available TTA solutions are extended to describe the multiphase flow in the reservoir. The required modifications and workflow are developed and verified using synthetic case studies. The value of the integrated analysis is then demonstrated by presenting a new method applicable for multi-phase production rate allocation in multi-zone, vertical I-Wells. The variable rate problem in the TTA context is later studied where the distorted signal is reconstructed by proposing normalization methods and developing a data-driven deconvolution algorithm. Finally, the effect of non-linear pressure drop across FCDs in I-Wells on applicability of the classical PTA solutions is investigated. The corrections to incorporate this effect into the classical PTA solutions is implemented as well as a workflow to decompose the total skin is presented. The value and applicability of the proposed workflow are later illustrated using real field case studies. This thesis is an important contribution into the understanding, modelling, monitoring and analysis of dynamic flow process in advanced wells

Wave Propagation

A wave is one of the basic physics phenomena observed by mankind since ancient time. The wave is also one of the most-studied physics phenomena that can be well described by mathematics. The study may be the best illustration of what is “science”, which approximates the laws of nature by using human defined symbols, operators, and languages. Having a good understanding of waves and wave propagation can help us to improve the quality of life and provide a pathway for future explorations of the nature and universe. This book introduces some exciting applications and theories to those who have general interests in waves and wave propagations, and provides insights and references to those who are specialized in the areas presented in the book

Instrumento de medición de temperatura con sensor piezoeléctrico

The construction of an instrument for the measurement of temperature based on the type of piezoelectric was carried out. The purpose of this instrument was to contribute to the metrology research line of the Integra research group. In the development of this project, a study was carried out on the method of sensing by the medium of these materials where the most appropriate sensor was determined and thanks to it was developed the conditioning of signal from the sensor, subsequently developed a digital processing system that was achieved thanks to a mathematical model generated by a prior identification of the system. The calibration adjustments were also made in order to improve its metrological characteristics. In addition, the temperature measurement was applied to the plant of the Integra research group.Se realizó la construcción de un instrumento para la medición de temperatura basado en el tipo de piezoeléctrico. El propósito de este instrumento fue contribuir a la línea de investigación en metrología del grupo de investigación Integra. En el desarrollo de este proyecto se realizó un estudio del método de sensado por medio de estos materiales donde se determinó el sensor más adecuado y gracias a ello se desarrolló el acondicionamiento de señal del sensor, posteriormente se desarrolló un sistema de procesamiento digital. eso se logró gracias a un modelo matemático generado por una identificación previa del sistema. También se realizaron los ajustes de calibración para mejorar sus características metrológicas. Además, se aplicó la medición de temperatura a la planta del grupo de investigación Integra

Postural Compensation for Unilateral Vestibular Loss

Postural control of upright stance was investigated in well-compensated, unilateral vestibular loss (UVL) subjects compared to age-matched control subjects. The goal was to determine how sensory weighting for postural control in UVL subjects differed from control subjects, and how sensory weighting related to UVL subjects’ functional compensation, as assessed by standardized balance and dizziness questionnaires. Postural control mechanisms were identified using a model-based interpretation of medial–lateral center-of-mass body-sway evoked by support-surface rotational stimuli during eyes-closed stance. The surface-tilt stimuli consisted of continuous pseudorandom rotations presented at four different amplitudes. Parameters of a feedback control model were obtained that accounted for each subject’s sway response to the surface-tilt stimuli. Sensory weighting factors quantified the relative contributions to stance control of vestibular sensory information, signaling body-sway relative to earth-vertical, and proprioceptive information, signaling body-sway relative to the surface. Results showed that UVL subjects made significantly greater use of proprioceptive, and therefore less use of vestibular, orientation information on all tests. There was relatively little overlap in the distributions of sensory weights measured in UVL and control subjects, although UVL subjects varied widely in the amount they could use their remaining vestibular function. Increased reliance on proprioceptive information by UVL subjects was associated with their balance being more disturbed by the surface-tilt perturbations than control subjects, thus indicating a deficiency of balance control even in well-compensated UVL subjects. Furthermore, there was some tendency for UVL subjects who were less able to utilize remaining vestibular information to also indicate worse functional compensation on questionnaires