Accelerometer based measurements of combustion in an automotive turbocharged diesel engine

The capability to detect combustion in a diesel engine has the potential of being an important control feature to meet increasingly stringent emission regulations, develop alternative combustion strategies, and use of biofuels. In this dissertation, block mounted accelerometers were investigated as potential feedback sensors for detecting combustion characteristics in a high-speed, high pressure common rail (HPCR), 1.9L diesel engine. Accelerometers were positioned in multiple placements and orientations on the engine, and engine testing was conducted under motored, single and pilot-main injection conditions. Engine tests were conducted at varying injection timings, engine loads, and engine speeds to observe the resulting time and frequency domain changes of the cylinder pressure and accelerometer signals. The frequency content of the cylinder pressure based signals and the accelerometer signals between 0.5 kHz and 6 kHz indicated a strong correlation with coherence values of nearly 1. The accelerometers were used to produce estimated combustion signals using the Frequency Response Functions (FRF) measured from the frequency domain characteristics of the cylinder pressure signals and the response of the accelerometers attached to the engine block. When compared to the actual combustion signals, the estimated combustion signals produced from the accelerometer response had Root Mean Square Errors (RMSE) between 7% and 25% of the actual signals peak value. Weighting the FRF’s from multiple test conditions along their frequency axis with the coherent output power reduced the median RMSE of the estimated combustion signals and the 95th percentile of RMSE produced from each test condition. The RMSE’s of the magnitude based combustion metrics including peak cylinder pressure, MPG, peak ROHR, and work estimated from the combustion signals produced by the accelerometer responses were between 15% and 50% of their actual value. The MPG measured from the estimated pressure gradient shared a direct relationship to the actual MPG. The location based combustion metrics such as the location of peak values and burn durations were capable of RMSE measurements as low as 0.9°. Overall, accelerometer based combustion sensing system was capable of detecting combustion and providing feedback regarding the in cylinder combustion process

High-Spin Molecules: Synthesis, X-ray Characterization, and Magnetic Behavior of Two New Cyano-Bridged Ni II 9 Mo V 6 and Ni II 9 W V 6 Clusters with a S = 12 Ground State

The preparations, X-ray structures, and magnetic characterizations are presented for two new pentadecanuclear cluster compounds:  [NiII{NiII(MeOH)3}8(μ-CN)30{MV(CN)3}6]·xMeOH·yH2O (MV = MoV (1) with x = 17, y = 1; MV = WV (2) with x = 15, y = 0). Both compounds crystallize in the monoclinic space group C2/c, with cell dimensions of a = 28.4957(18) Å, b = 19.2583(10) Å, c = 32.4279(17) Å, β = 113.155(6)°, and Z = 4 for 1 and a = 28.5278(16) Å, b = 19.2008(18) Å, c = 32.4072(17) Å, β = 113.727(6)°, and Z = 4 for 2. The structures of 1 and 2 consist of neutral cluster complexes comprising 15 metal ions, 9 NiII and 6 MV, all linked by μ-cyano ligands. Magnetic susceptibilities and magnetization measurements of compounds 1 and 2 in the crystalline and dissolved state indicate that these clusters have a S = 12 ground state, originating from intracluster ferromagnetic exchange interactions between the μ-cyano-bridged metal ions of the type NiII−NC−MV. Indeed, these data show clearly that the cluster molecules stay intact in solution. Ac magnetic susceptibility measurements reveal that the cluster compounds exhibit magnetic susceptibility relaxation phenomena at low temperatures since, with nonzero dc fields, χ‘ ‘M has a nonzero value that is frequency dependent. However, there appears no out-of-phase (χ‘ ‘M) signal in zero dc field down to 1.8 K, which excludes the expected signature for a single molecule magnet. This finding is confirmed with the small uniaxial magnetic anisotropy value for D of 0.015 cm-1, deduced from the high-field, high-frequency EPR measurement, which distinctly reveals a positive sign in D. Obviously, the overall magnetic anisotropy of the compounds is too low, and this may be a consequence of a small single ion magnetic anisotropy combined with the highly symmetric arrangement of the metal ions in the cluster molecule.

Flujo de potencia entre estructuras complejas sometidas a excitaciones de alta frecuencia y aplicaciones a la detección de daño estructural

El tema central de investigación en esta Tesis es el estudio del comportamientodinámico de una estructura mediante modelos que describen la distribución deenergía entre los componentes de la misma y la aplicación de estos modelos parala detección de daños incipientes.Los ensayos dinámicos son un modo de extraer información sobre las propiedadesde una estructura. Si tenemos un modelo de la estructura se podría ajustar éstepara que, con determinado grado de precisión, tenga la misma respuesta que elsistema real ensayado. Después de que se produjese un daño en la estructura,la respuesta al mismo ensayo variará en cierta medida; actualizando el modelo alas nuevas condiciones podemos detectar cambios en la configuración del modeloestructural que nos condujeran a la conclusión de que en la estructura se haproducido un daño.De este modo, la detección de un daño incipiente es posible si somos capacesde distinguir una pequeña variación en los parámetros que definen el modelo. Unrégimen muy apropiado para realizar este tipo de detección es a altas frecuencias,ya que la respuesta es muy dependiente de los pequeños detalles geométricos,dado que el tamaño característico en la estructura asociado a la respuesta esdirectamente proporcional a la velocidad de propagación de las ondas acústicas enel sólido, que para una estructura dada es inalterable, e inversamente proporcionala la frecuencia de la excitación. Al mismo tiempo, esta característica de la respuestaa altas frecuencias hace que un modelo de Elementos Finitos no sea aplicable enla práctica, debido al alto coste computacional.Un modelo ampliamente utilizado en el cálculo de la respuesta de estructurasa altas frecuencias en ingeniería es el SEA (Statistical Energy Analysis). El SEAaplica el balance energético a cada componente estructural, relacionando la energíade vibración de estos con la potencia disipada por cada uno de ellos y la potenciatransmitida entre ellos, cuya suma debe ser igual a la potencia inyectada a cadacomponente estructural. Esta relación es lineal y viene caracterizada por los factoresde pérdidas. Las magnitudes que intervienen en la respuesta se consideranpromediadas en la geometría, la frecuencia y el tiempo.Actualizar el modelo SEA a datos de ensayo es, por lo tanto, calcular losfactores de pérdidas que reproduzcan la respuesta obtenida en éste. Esta actualización,si se hace de manera directa, supone la resolución de un problema inversoque tiene la característica de estar mal condicionado. En la Tesis se propone actualizarel modelo SEA, no en término de los factores de pérdidas, sino en términos deparámetros estructurales que tienen sentido físico cuando se trata de la respuestaa altas frecuencias, como son los factores de disipación de cada componente, susdensidades modales y las rigideces características de los elementos de acoplamiento.Los factores de pérdidas se calculan como función de estos parámetros. Estaformulación es desarrollada de manera original en esta Tesis y principalmente sefunda en la hipótesis de alta densidad modal, es decir, que en la respuesta participanun gran número de modos de cada componente estructural.La teoría general del método SEA, establece que el modelo es válido bajounas hipótesis sobre la naturaleza de las excitaciones externas muy restrictivas,como que éstas deben ser de tipo ruido blanco local. Este tipo de carga es difícil dereproducir en condiciones de ensayo. En la Tesis mostramos con casos prácticos queesta restricción se puede relajar y, en particular, los resultados son suficientementebuenos cuando la estructura se somete a una carga armónica en escalón.Bajo estas aproximaciones se desarrolla un algoritmo de optimización por pasosque permite actualizar un modelo SEA a un ensayo transitorio cuando la carga esde tipo armónica en escalón. Este algoritmo actualiza el modelo no solamente parauna banda de frecuencia en particular sino para diversas bandas de frecuencia demanera simultánea, con el objetivo de plantear un problema mejor condicionado.Por último, se define un índice de daño que mide el cambio en la matriz depérdidas cuando se produce un daño estructural en una localización concreta deun componente. Se simula numéricamente la respuesta de una estructura formadapor vigas donde producimos un daño en la sección de una de ellas; como se tratade un cálculo a altas frecuencias, la simulación se hace mediante el Método delos Elementos Espectrales para lo que ha sido necesario desarrollar dentro de laTesis un elemento espectral de tipo viga dañada en una sección determinada. Losresultados obtenidos permiten localizar el componente estructural en que se haproducido el daño y la sección en que éste se encuentra con determinado grado deconfianza.AbstractThe main subject under research in this Thesis is the study of the dynamic behaviourof a structure using models that describe the energy distribution betweenthe components of the structure and the applicability of these models to incipientdamage detection.Dynamic tests are a way to extract information about the properties of astructure. If we have a model of the structure, it can be updated in order toreproduce the same response as in experimental tests, within a certain degree ofaccuracy. After damage occurs, the response will change to some extent; modelupdating to the new test conditions can help to detect changes in the structuralmodel leading to the conclusión that damage has occurred.In this way incipient damage detection is possible if we are able to detect srnallvariations in the model parameters. It turns out that the high frequency regimeis highly relevant for incipient damage detection, because the response is verysensitive to small structural geometric details. The characteristic length associatedwith the response is proportional to the propagation speed of acoustic waves insidethe solid, but inversely proportional to the excitation frequency. At the same time,this fact makes the application of a Finite Element Method impractical due to thehigh computational cost.A widely used model in engineering when dealing with the high frequencyresponse is SEA (Statistical Energy Analysis). SEA applies the energy balance toeach structural component, relating their vibrational energy with the dissipatedpower and the transmitted power between the different components; their summust be equal to the input power to each of them. This relationship is linear andcharacterized by loss factors. The magnitudes considered in the response shouldbe averaged in geometry, frequency and time.SEA model updating to test data is equivalent to calculating the loss factorsthat provide a better fit to the experimental response. This is formulated as an illconditionedinverse problem. In this Thesis a new updating algorithm is proposedfor the study of the high frequency response regime in terms of parameters withphysical meaning such as the internal dissipation factors, modal densities andcharacteristic coupling stiffness. The loss factors are then calculated from theseparameters. The approach is developed entirely in this Thesis and is mainlybased on a high modal density asumption, that is to say, a large number of modescontributes to the response.General SEA theory establishes the validity of the model under the asumptionof very restrictive external excitations. These should behave as a local white noise.This kind of excitation is difficult to reproduce in an experimental environment.In this Thesis we show that in practical cases this assumption can be relaxed, inparticular, results are good enough when the structure is excited with a harmonicstep function.Under these assumptions an optimization algorithm is developed for SEAmodel updating to a transient test when external loads are harmonic step functions.This algorithm considers the response not only in a single frequency band,but also for several of them simultaneously.A damage index is defined that measures the change in the loss factor matrixwhen a damage has occurred at a certain location in the structure. The structuresconsidered in this study are built with damaged beam elements; as we are dealingwith the high frequency response, the numerical simulation is implemented witha Spectral Element Method. It has therefore been necessary to develop a spectralbeam damaged element as well. The reported results show that damage detectionis possible with this algorithm, moreover, damage location is also possible withina certain degree of accuracy.

AlN-based BAW resonators with CNT electrodes for gravimetric biosensing

Solidly mounted resonators (SMRs) with a top carbon nanotubes (CNTs) surface coating that doubles as an electrode and as a sensing layer have been fabricated. The influence of the CNTs on the frequency response of the resonators was studied by direct comparison to identical devices with a top metallic electrode. It was found that the CNTs introduced significantly less mass load on the resonators and these devices exhibited a greater quality factor, Q (>2000, compared to ∼1000 for devices with metal electrodes), which increases the gravimetric sensitivity of the devices by allowing the tracking of smaller frequency shifts. Protein solutions with different concentrations were loaded on the top of the resonators and their responses to mass-load from physically adsorbed coatings were investigated. Results show that resonators using CNTs as the top electrode exhibited a higher frequency change for a given load (∼0.25 MHz cm2 ng−1) compared to that of a metal thin film electrode (∼0.14 MHz cm2 ng−1), due to the lower mass of the CNTelectrodes and their higher active surface area compared to that of a thin film metal electrode. It is therefore concluded that the use of CNTelectrodes on resonators for their use as gravimetric biosensors is a significant improvement over metallic electrodes that are normally employed.

Stability and Transient Performance Assessment in a COTS-Module-Based Distributed DC/DC System

This paper introduces a method to analyze and predict stability and transient performance of a distributed system where COTS (Commercial-off-the-shelf) modules share an input filter. The presented procedure is based on the measured data from the input and output terminals of the power modules. The required information for the analysis is obtained by performing frequency response measurements for each converter. This attained data is utilized to compute special transfer functions, which partly determine the source and load interactions within the converters. The system level dynamic description is constructed based on the measured and computed transfer functions introducing cross-coupling mechanisms within the system. System stability can be studied based on the well-known impedance- related minor-loop gain at an arbitrary interface within the system.

Implementación de instrumentación virtual con LaBVIEW

El objetivo del PFC es el diseño e implementación de una aplicación que funcione como osciloscopio, analizador de espectro y generador de funciones virtual, todo dentro de la misma aplicacion. Mediante una tarjeta de adquisición de datos tomaremos muestras de señales del mundo real (sistema analógico) para generar datos que puedan ser manipulados por un ordenador (sistema digital). Con esta misma tarjeta también se podrán generar señales básicas, tales como señales senoidales, cuadradas.... y además se ha añadido la funcionalidad de generar señales moduladas en frecuencia, señales tipo Chirp (usadas comúnmente tanto en aplicaciones sonar y radar, como en transmisión óptica) o PRN (ruido pseudo-aleatorio que consta de una secuencia determinista de pulsos que se repite cada periodo, usada comúnmente en receptores GPS), como también señales ampliamente conocidas como el ruido blanco Gaussiano o el ruido blanco uniforme. La aplicación mostrará con detalle las señales adquiridas y analizará de diversas maneras esas señales. Posee la función de enventanado de los tipos de ventana mas comunes, respuesta en frecuencia, transformada de Fourier, etc. La configuración es elegida por el usuario en un entorno amigable y de visualización atractiva. The objective of the PFC is the design and implementation of an application that works as oscilloscope, spectrum analyzer and virtual signal generator, all within the same application. Through a data acquisition card, the user can take samples of real-world signals (analog system) to generate data that can be manipulated by a computer (digital system). This same card can also generate basic signals, such as sine waves, square waves, sawtooth waves.... and further has added other functionalities as frequency modulated signals generation, Chirp signals type generation (commonly used in both sonar and radar applications, such as optical transmission) or PRN (pseudo-random noise sequence comprising a deterministic pulse that repeats every period, commonly used in GPS receivers). It also can generate widely known as Gaussian white noise signals or white noise uniform signals. The application will show in detail the acquired signals and will analyze these signals in different ways selected by the user. Windowing function has the most common window types, frequency response, Fourier transform are examples of what kind of analyzing that can be processed. The configuration is chosen by the user throught friendly and attractive displays and panels.

High-Acoustic-Impedance Tantalum Oxide Layers for Insulating Acoustic Reflectors

This work describes the assessment of the acoustic properties of sputtered tantalum oxide films intended for use as high-impedance films of acoustic reflectors for solidly mounted resonators operating in the gigahertz frequency range. The films are grown by sputtering a metallic tantalum target under different oxygen and argon gas mixtures, total pressures, pulsed dc powers, and substrate biases. The structural properties of the films are assessed through infrared absorption spectroscopy and X-ray diffraction measurements. Their acoustic impedance is assessed by deriving the mass density from X-ray reflectometry measurements and the acoustic velocity from picosecond acoustic spectroscopy and the analysis of the frequency response of the test resonators.

Influence of Crystal Quality on the Excitation and Propagation of Surface and Bulk Acoustic Waves in Polycrystalline AlN Films

We investigate the excitation and propagation of acoustic waves in polycrystalline aluminum nitride films along the directions parallel and normal to the c-axis. Longitudinal and transverse propagations are assessed through the frequency response of surface acoustic wave and bulk acoustic wave devices fabricated on films of different crystal qualities. The crystalline properties significantly affect the electromechanical coupling factors and acoustic properties of the piezoelectric layers. The presence of misoriented grains produces an overall decrease of the piezoelectric activity, degrading more severely the excitation and propagation of waves traveling transversally to the c-axis. It is suggested that the presence of such crystalline defects in c-axis-oriented films reduces the mechanical coherence between grains and hinders the transverse deformation of the film when the electric field is applied parallel to the surface.

On the lateral excitation of shear modes in AlN layered resonators

In this paper we describe the fabrication and frequency characterization of different structures intended for the lateral excitation of shear modes in AlN c-axis-oriented films, which are at the same time designed to minimize the excitation of longitudinal modes. Laterally excited resonators were built on partially metallic (SiO2, W) and insulating (SiOC, Si3N4) acoustic mirrors built on silicon substrates, and on insulating mirrors (SiO2, TaOx) built on insulating glass plates. TiOx seed layers were used to stimulate the growth of highly c-axis oriented AlN films, which was confirmed by XRD and SAW measurements. Coplanar Mo electrodes of different geometries were defined on top of the AlN films to excite the shear modes. All the structures analyzed displayed a clear longitudinal mode, corresponding to an acoustic velocity of 11000 m/s, but a null or extremely weak shear response corresponding to a sound velocity of around 6350 m/s. The simulation of the frequency response based on Mason's model confirms that the shear resonance is extremely weak. The observed longitudinal modes are attributed either to the field applied between the electrodes and a conductive plane (metallic layer or Si substrate) or to the electric field parallel to the c-axis in the edges of the electrodes or in tilted grains. The low excitation of shear modes is attributed to the very low values of electric field strength parallel to the surface.

Piezoelectric and electroacoustic properties of Ti-doped AlN thin films as a function of Ti content

In this work we present the assessment of the structural and piezoelectric properties of Al(0.5-x)TixN0.5 compounds (titanium content menor que6% atomic), which are expected to possess improved properties than conventional AlN films, such as larger piezoelectric activity, thermal stability of frequency and temperature resistance. Al:Ti:N films were deposited from a twin concentric target of Al and Ti by reactive AC sputtering, which provided films with a radial gradient of the Ti concentration. The properties of the films were investigated as a function of their composition, which was measured by electron dispersive energy dispersive X-ray spectroscopy and Rutherford backscattering spectrometry. The microstructure and morphology of the films were assessed by X-ray diffraction and infrared reflectance. Their electroacoustic properties and dielectric constant were derived from the frequency response of BAW test resonators. Al:Ti:N films properties appear to be strongly dependent on the Ti content, which modifies the AlN wurtzite crystal structure leading to greater dielectric constant, lower sound velocities, lower electromechanical factor and moderately improved temperature coefficient of the resonant frequency.

Theoretical Simulation of the A5 VEB Structure Pyrotechnique Shock Propagation

This paper presents some of the modelling criteria that have been used for the study of pyrotechnic shock propagation in the A5 VEB Structure, as well as the main conclusions from a mathematical model of the axymmetric effects in it. The separation of the lower stage of the ARIANE 5 Vehicle Equipment Bay (VEB)Structure is to be done using a pyrotechnic device. The wave propagation effects produced by the explosion have been analyzed with a computer program using as shape functions the analytical solution to the frequency response of a Timoshenko-Rayleigh beams and shells in that way the discretization can have elements as large as possible, depending on the material properties and boundary conditions. Moreover an enormous amount of possibilities in the treatment of concentrated masses, springs and dashpots, either with respect to a fixed reference or between nodes, is open for translational as well as rotational degrees of freedom.

Predicción de la ley de atenuación, frecuencia dominante y espectro de respuesta en vibraciones producidas por voladuras a cielo abierto

El presente proyecto de fin de carrera describe y analiza el estudio integral del efecto de las vibraciones producidas por voladuras superficiales realizadas en el proyecto del “Tercer Juego de Esclusas” ejecutado para la Expansión del Canal de Panamá. Se recopilan un total de 53 registros, data generada por el monitoreo de 7 sismógrafos en 10 voladuras de producción realizadas en el año 2010. El fenómeno vibratorio tiene dos parámetros fundamentales, la velocidad pico-partícula (PPV) y la frecuencia dominante, los cuales caracterizan cuan dañino puede ser éste frente a su influencia sobre las estructuras civiles; por ello, se pretende caracterizarlas y fundamentalmente predecirlas, lo que permitirá su debido control. En función a lo expuesto, el estudio realizado consta de dos partes, la primera describe el comportamiento del terreno mediante la estimación de la ley de atenuación de la velocidad pico-partícula a través del uso de la regresión lineal por mínimos cuadrados; la segunda detalla un procedimiento validable para la predicción de la frecuencia dominante y del pseudo-espectro de respuesta de velocidad (PVRS) basada en la teoría de Newmark & Hall. Se ha obtenido: (i) la ley de atenuación del terreno para distintos grados de fiabilidad, (ii) herramientas de diseño de voladuras basadas en la relación de carga – distancia, (iii) la demostración que los valores de PPV se ajustan a una distribución log-normal, (iv) el mapa de isolíneas de PPV para el área de estudio, (v) una técnica detallada y válida para la predicción de la frecuencia dominante y del espectro de respuesta, (vi) formulaciones matemáticas de los factores de amplificación para el desplazamiento, velocidad y aceleración, (vii) mapa de isolíneas de amplificación para el área de estudio. A partir de los resultados obtenidos se proporciona información útil para su uso en el diseño y control de las voladuras posteriores del proyecto. ABSTRACT This project work describes and analyzes the comprehensive study of the effect of the vibrations produced by surface blasting carried out in the "Third Set of Locks" project executed for the expansion of the Panama Canal. A total of 53 records were collected, with the data generated by the monitoring of 7 seismographs in 10 production blasts carried out in 2010. The vibratory phenomenon has two fundamental parameters, the peak-particle velocity (PPV) and the dominant frequency, which characterize how damaging this can be compared to their influence on structures, which is why this is intended to characterize and predict fundamentally, that which allows proper control. Based on the above, the study consists of two parts; the first describes the behavior of the terrain by estimating the attenuation law for peak-particle velocity by using the ordinary least squares regression analysis, the second details a validable procedure for the prediction of the dominant frequency and pseudo-velocity response spectrum (PVRS) based on the theory of Newmark & Hall. The following have been obtained: (i) the attenuation law of the terrain for different degrees of reliability, (ii) blast design tools based on charge-distance ratio, (iii) the demonstration that the values of PPV conform to a log-normal distribution, (iv) the map of isolines of PPV for the area of study (v) detailed and valid technique for predicting the dominant frequency response spectrum, (vi) mathematical formulations of the amplification factors for displacement, velocity and acceleration, (vii) amplification of isolines map for the study area. From the results obtained, the study provides useful information for use in the design and control of blasting for subsequent projects.

3-dimensional binaural sound rendering using acoustic measurements stored in the SOFA format

Several groups all over the world are researching in several ways to render 3D sounds. One way to achieve this is to use Head Related Transfer Functions (HRTFs). These measurements contain the Frequency Response of the human head and torso for each angle. Some years ago, was only possible to measure these Frequency Responses only in the horizontal plane. Nowadays, several improvements have made possible to measure and use 3D data for this purpose. The problem was that the groups didn't have a standard format file to store the data. That was a problem when a third part wanted to use some different HRTFs for 3D audio rendering. Every of them have different ways to store the data. The Spatially Oriented Format for Acoustics or SOFA was created to provide a solution to this problem. It is a format definition to unify all the previous different ways of storing any kind of acoustics data. At the moment of this project they have defined some basis for the format and some recommendations to store HRTFs. It is actually under development, so several changes could come. The SOFA[1] file format uses a numeric container called netCDF[2], specifically the Enhaced data model described in netCDF 4 that is based on HDF5[3]. The SoundScape Renderer (SSR) is a tool for real-time spatial audio reproduction providing a variety of rendering algorithms. The SSR was developed at the Quality and Usability Lab at TU Berlin and is now further developed at the Institut für Nachrichtentechnik at Universität Rostock [4]. This project is intended to be an introduction to the use of SOFA files, providing a C++ API to manipulate them and adapt the binaural renderer of the SSR for working with the SOFA format. RESUMEN. El SSR (SoundScape Renderer) es un programa que está siendo desarrollado actualmente por la Universität Rostock, y previamente por la Technische Universität Berlin. El SSR es una herramienta diseñada para la reproducción y renderización de audio 2D en tiempo real. Para ello utiliza diversos algoritmos, algunos orientados a sistemas formados por arrays de altavoces en diferentes configuraciones y otros algoritmos diseñados para cascos. El principal objetivo de este proyecto es dotar al SSR de la capacidad de renderizar sonidos binaurales en 3D. Este proyecto está centrado en el binaural renderer del SSR. Este algoritmo se basa en el uso de HRTFs (Head Related Transfer Function). Las HRTFs representan la función de transferencia del sistema formado por la cabeza y el torso del oyente. Esta función es medida desde diferentes ángulos. Con estos datos el binaural renderer puede generar audio en tiempo real simulando la posición de diferentes fuentes. Para poder incluir una base de datos con HRTFs en 3D se ha hecho uso del nuevo formato SOFA (Spatially Oriented Format for Acoustics). Este nuevo formato se encuentra en una fase bastante temprana de su desarrollo. Está pensado para servir como formato estándar para almacenar HRTFs y cualquier otro tipo de medidas acústicas, ya que actualmente cada laboratorio cuenta con su propio formato de almacenamiento y esto hace bastante difícil usar varias bases de datos diferentes en un mismo proyecto. El formato SOFA hace uso del contenedor numérico netCDF, que a su vez esta basado en un contenedor más básico llamado HRTF-5. Para poder incluir el formato SOFA en el binaural renderer del SSR se ha desarrollado una API en C++ para poder crear y leer archivos SOFA con el fin de utilizar los datos contenidos en ellos dentro del SSR.

Diseño de la sala 6 de Kinépolis (Madrid) con un sistema Dolby ATMOS

El objetivo de este Proyecto Fin de Carrera es el estudio y simulación de la sonorización de una sala de cine mediante la utilización del sistema DOLBY ATMOS. Para ello, se simulará la sala 6 del complejo de cines Kinépolis de Madrid utilizando el programa de simulación electroacústica EASE en el que se dispondrá el sistema de sonido DOLBY ATMOS. Primero se procederá a realizar el modelo geométrico en el programa EASE, a partir de los planos de la instalación y medidas realizadas en el recinto. Este programa de simulación permite obtener los parámetros acústicos y electroacústicos necesarios para realizar el estudio de la sala. Luego se diseñará el sistema de sonido de acuerdo a las disposiciones del sistema DOLBY ATMOS, mediante la ubicación de sistemas de altavoces de cine existentes en el mercado, siempre intentando mantener el uso de la sala de forma convencional como DOLBY DIGITAL y cumpliendo los requisitos de uniformidad y ángulos de apuntamiento recomendados por DOLBY. A continuación, una vez dispuestos los altavoces, se procederá a su configuración, realizando una ecualización y ajuste de nivel de manera individual para cada una de las fuentes sonoras, tanto de los altavoces de pantalla, altavoces de surround de pared y techo y los altavoces de subgraves. Como resultado de todo ello, se comprobarán parámetros como la inteligibilidad, respuesta impulsiva, respuesta en frecuencia y tiempo de reverberación en diferentes puntos de escucha, comparando los resultados obtenidos entre ellos. También se realizará una configuración compatible con el sistema de sonido 7.1, realizando su correspondiente configuración, ecualización, ajuste y aplicando los retardos necesarios. Una vez esté todo configurado, será dar un presupuesto de lo que supondría la reformar de un cine convencional a un sistema DOLBY ATMOS, teniendo en cuenta el número de altavoces disponibles en la sala actual, los modelos utilizados, amplificadores y mano de obra. También se realizará un diagrama de conexionado del sistema de sonido utilizado en el proyecto, incluyendo todos los parámetros necesarios de la configuración. Por último se comprobará la viabilidad técnica y económica del sistema diseñado, viendo cuál es la opción que más se adecua a cada necesidad y sugiriendo soluciones a los posibles problemas que se puedan encontrar. ABSTRACT. The main aim of this Project is the study and simulation of the sound of a movie theater by using DOLBY ATMOS system. It is going to be simulated the movie theatre 6 at Kinepolis cinema complex in Madrid using the simulation program EASE according to the sound system DOLBY ATMOS. First of all we proceed to conduct the geometric pattern in the EASE program, from installation drawings and measurements made on the premises. This simulation program allows getting the acoustic and electroacoustic parameters necessary for the study of the theatre. Then the sound system designed according to the suggestions of ATMOS DOLBY, by locating theater speaker systems on the market, always trying to keep the use of the room for DOLBY DIGITAL conventional and meeting the requirements of uniformity and pointing angles DOLBY recommended. Then, once the speakers are prepared, you can proceed to configure, make equalization and level setting individually for each of the sound sources, both screen speakers, surround speakers (wall and ceiling) and subwoofer. As a result, parameters are checked as intelligibility, impulse response, frequency response and reverberation time in different listening points, comparing the results between each other. There will also be configured to support 7.1 sound system, making the corresponding settings, equalization, level setting and applying the necessary delays. Once everything is configured, it will give an estimate of what would be the reform of a conventional film DOLBY ATMOS system, taking into account the number of speakers available in the current room, the models used, amplifiers and labor. Also there will be a wiring diagram of the sound system used in this project, including all of the configuration parameters needed. Finally, check the technical and economic feasibility of the designed system, seeing what is the option that best suits to each need and suggesting possible solutions to problems you might find during the process.

Análisis de micromovilidad en vástagos femorales mediante ensayo dinámico de oscilaciones libres

La artroplastia de cadera se considera uno de los mayores avances quirúrgicos de la Medicina. La aplicación de esta técnica de Traumatología se ha incrementado notablemente en los últimos anos, a causa principalmente del progresivo incremento de la esperanza de vida. En efecto, con la edad aumentan los problemas de artrosis y osteoporosis, enfermedades típicas de las articulaciones y de los huesos que requieren en muchos casos la sustitución protésica total o parcial de la articulación. El buen comportamiento funcional de una prótesis depende en gran medida de la estabilidad primaria, es decir, el correcto anclaje de la prótesis en el momento de su implantación. Las prótesis no cementadas basan su éxito a largo plazo en la osteointegración que tiene lugar entre el material protésico y el tejido óseo, y para lograrla es imprescindible conseguir unas buenas condiciones de estabilidad primaria. El aflojamiento aséptico es la principal causa de fallo de artroplastia total de cadera. Este es un fenómeno en el que, debido a complejas interacciones de factores mecánicos y biológicos, se producen movimientos relativos que comprometen la funcionalidad del implante. La minimización de los correspondientes danos depende en gran medida de la detección precoz del aflojamiento. Para lograr la detección temprana del aflojamiento aséptico del vástago femoral se han ensayado diferentes técnicas, tanto in vivo como in vitro: análisis numéricos y técnicas experimentales basadas en sensores de movimientos provocados por cargas transmitidas natural o artificialmente, tales como impactos o vibraciones de distintas frecuencias. Los montajes y procedimientos aplicados son heterogéneos y, en muchas ocasiones, complejos y costosos, no existiendo acuerdo sobre una técnica simple y eficaz de aplicación general. Asimismo, en la normativa vigente que regula las condiciones que debe cumplir una prótesis previamente a su comercialización, no hay ningún apartado referido específicamente a la evaluación de la bondad del diseño del vástago femoral con respecto a la estabilidad primaria. El objetivo de esta tesis es desarrollar una metodología para el análisis, in vitro, de la estabilidad de un vástago femoral implantado, a fin de poder evaluar las técnicas de implantación y los diferentes diseños de prótesis previamente a su oferta en el mercado. Además se plantea como requisito fundamental que el método desarrollado sea sencillo, reversible, repetible, no destructivo, con control riguroso de parámetros (condiciones de contorno de cargas y desplazamientos) y con un sistema de registro e interpretación de resultados rápido, fiable y asequible. Como paso previo, se ha realizado un análisis cualitativo del problema de contacto en la interfaz hueso-vástago aplicando una técnica optomecánica del campo continuo (fotoelasticidad). Para ello se han fabricado tres modelos en 2D del conjunto hueso-vástago, simulando tres tipos de contactos en la interfaz: contacto sin adherencia y con holgura, contacto sin adherencia y sin holgura, y contacto con adherencia y homogéneo. Aplicando la misma carga a cada modelo, y empleando la técnica de congelación de tensiones, se han visualizado los correspondientes estados tensionales, siendo estos más severos en el modelo de unión sin adherencia, como cabía esperar. En todo caso, los resultados son ilustrativos de la complejidad del problema de contacto y confirman la conveniencia y necesidad de la vía experimental para el estudio del problema. Seguidamente se ha planteado un ensayo dinámico de oscilaciones libres con instrumentación de sensores resistivos tipo galga extensométrica. Las muestras de ensayo han sido huesos fémur en todas sus posibles variantes: modelos simplificados, hueso sintético normalizado y hueso de cadáver, seco y fresco. Se ha diseñado un sistema de empotramiento del extremo distal de la muestra (fémur) con control riguroso de las condiciones de anclaje. La oscilación libre de la muestra se ha obtenido mediante la liberación instantánea de una carga estética determinada y aplicada previamente, bien con una maquina de ensayo o bien por gravedad. Cada muestra se ha instrumentado con galgas extensométricas convencionales cuya señal se ha registrado con un equipo dinámico comercial. Se ha aplicado un procedimiento de tratamiento de señal para acotar, filtrar y presentar las respuestas de los sensores en el dominio del tiempo y de la frecuencia. La interpretación de resultados es de tipo comparativo: se aplica el ensayo a una muestra de fémur Intacto que se toma de referencia, y a continuación se repite el ensayo sobre la misma muestra con una prótesis implantada; la comparación de resultados permite establecer conclusiones inmediatas sobre los efectos de la implantación de la prótesis. La implantación ha sido realizada por un cirujano traumatólogo utilizando las mismas técnicas e instrumental empleadas en el quirófano durante la práctica clínica real, y se ha trabajado con tres vástagos femorales comerciales. Con los resultados en el dominio del tiempo y de la frecuencia de las distintas aplicaciones se han establecido conclusiones sobre los siguientes aspectos: Viabilidad de los distintos tipos de muestras sintéticas: modelos simplificados y fémur sintético normalizado. Repetibilidad, linealidad y reversibilidad del ensayo. Congruencia de resultados con los valores teóricos deducidos de la teoría de oscilaciones libres de barras. Efectos de la implantación de tallos femorales en la amplitud de las oscilaciones, amortiguamiento y frecuencias de oscilación. Detección de armónicos asociados a la micromovilidad. La metodología se ha demostrado apta para ser incorporada a la normativa de prótesis, es de aplicación universal y abre vías para el análisis de la detección y caracterización de la micromovilidad de una prótesis frente a las cargas de servicio. ABSTRACT Total hip arthroplasty is considered as one of the greatest surgical advances in medicine. The application of this technique on Traumatology has increased significantly in recent years, mainly due to the progressive increase in life expectancy. In fact, advanced age increases osteoarthritis and osteoporosis problems, which are typical diseases of joints and bones, and in many cases require full or partial prosthetic replacement on the joint. Right functional behavior of prosthesis is highly dependent on the primary stability; this means it depends on the correct anchoring of the prosthesis at the time of implantation. Uncemented prosthesis base their long-term success on the quality of osseointegration that takes place between the prosthetic material and bone tissue, and to achieve this good primary stability conditions is mandatory. Aseptic loosening is the main cause of failure in total hip arthroplasty. This is a phenomenon in which relative movements occur, due to complex interactions of mechanical and biological factors, and these micromovements put the implant functionality at risk. To minimize possible damage, it greatly depends on the early detection of loosening. For this purpose, various techniques have been tested both in vivo and in vitro: numerical analysis and experimental techniques based on sensors for movements caused by naturally or artificially transmitted loads, such as impacts or vibrations at different frequencies. The assemblies and methods applied are heterogeneous and, in many cases, they are complex and expensive, with no agreement on the use of a simple and effective technique for general purposes. Likewise, in current regulations for governing the conditions to be fulfilled by the prosthesis before going to market, there is no specific section related to the evaluation of the femoral stem design in relation to primary stability. The aim of this thesis is to develop a in vitro methodology for analyzing the stability of an implanted femoral stem, in order to assess the implantation techniques and the different prosthesis designs prior to its offer in the market. We also propose as a fundamental requirement that the developed testing method should be simple, reversible, repeatable, non-destructive, with close monitoring of parameters (boundary conditions of loads and displacements) and with the availability of a register system to record and interpret results in a fast, reliable and affordable manner. As a preliminary step, we have performed a qualitative analysis of the contact problems in the bone-stem interface, through the application of a continuous field optomechanical technique (photoelasticity). For this proposal three 2D models of bone–stem set, has been built simulating three interface contact types: loosened an unbounded contact, unbounded and fixed contact, and bounded homogeneous contact. By means of applying the same load to each model, and using the stress freezing technique, it has displayed the corresponding stress states, being more severe as expected, in the unbounded union model. In any case, the results clearly show the complexity of the interface contact problem, and they confirm the need for experimental studies about this problem. Afterward a free oscillation dynamic test has been done using resistive strain gauge sensors. Test samples have been femur bones in all possible variants: simplified models, standardized synthetic bone, and dry and cool cadaveric bones. An embedding system at the distal end of the sample with strong control of the anchoring conditions has been designed. The free oscillation of the sample has been obtained by the instantaneous release of a static load, which was previously determined and applied to the sample through a testing machine or using the gravity force. Each sample was equipped with conventional strain gauges whose signal is registered with a marketed dynamic equipment. Then, it has applied a signal processing procedure to delimit, filter and present the time and frequency response signals from the sensors. Results are interpreted by comparing different trials: the test is applied to an intact femur sample which is taken as a reference, and then this test is repeated over the same sample with an implanted prosthesis. From comparison between results, immediate conclusions about the effects of the implantation of the prosthesis can be obtained. It must be said that the implementation has been made by an expert orthopedic surgeon using the same techniques and instruments as those used in clinical surgery. He has worked with three commercial femoral stems. From the results obtained in the time and frequency domains for the different applications the following conclusions have been established: Feasibility of the different types of synthetic samples: simplified models and standardized synthetic femur. Repeatability, linearity and reversibility of the testing method. Consistency of results with theoretical values deduced from the bars free oscillations theory. Effects of introduction of femoral stems in the amplitude, damping and frequencies of oscillations Detection of micromobility associated harmonics. This methodology has been proved suitable to be included in the standardization process of arthroplasty prosthesis, it is universally applicable and it allows establishing new methods for the analysis, detection and characterization of prosthesis micromobility due to functional loads.