### Finalized Master theses

Number of entries: 51

### Bulk viscosities of color-flavor quark matter

Status: defended (31/03/2011)
Student: Robert Bierkandt
Supervised by: Cristina Manuel Hidalgo

We evaluate the three bulk viscosity coefficients $\zeta_1, \zeta_2$ and $\zeta_3$ in the color-flavor locked (CFL) superfluid phase due to phonons and kaons, which are the lightest modes in that system. We first show that the computation is rather analogous to the computation of the same coefficients…
Status: defended (31/03/2011)
Student: Robert Bierkandt
Supervised by: Cristina Manuel Hidalgo

We evaluate the three bulk viscosity coefficients $\zeta_1, \zeta_2$ and $\zeta_3$ in the color-flavor locked (CFL) superfluid phase due to phonons and kaons, which are the lightest modes in that system. We first show that the computation is rather analogous to the computation of the same coefficients in superfluid $^4$He, as due to phonons and rotons. For astrophysical applications, we also find the value of the viscosities when there is a periodic disturbance, and the viscosities also depend on the frequency of the disturbance. In a temperature regime that might be of astrophysical relevance, we find that the contributions of both the phonons and kaons should be considered, and that $\zeta_2$ is much less that the same coefficient in unpaired quark matter.

### Study of the mechanical response of the LTP's test masses due to the action of control heaters in LISA Pathfinder

Status: defended (25/02/2011)
Student: Ferran Gibert Gutiérrez
Supervised by: José Alberto Lobo Gutiérrez; Chester, E.
University: Universitat Politècnica de Catalunya

The main aim of the LISA Pathfinder (LPF) mission is to place two Test Masses into a very stable drag free environment and make very precise interferometric measurements of displacements between them. In order to achieve such an objective, it is necessary to characterize and model the disturbances that…
Status: defended (25/02/2011)
Student: Ferran Gibert Gutiérrez
Supervised by: José Alberto Lobo Gutiérrez; Chester, E.
University: Universitat Politècnica de Catalunya

The main aim of the LISA Pathfinder (LPF) mission is to place two Test Masses into a very stable drag free environment and make very precise interferometric measurements of displacements between them. In order to achieve such an objective, it is necessary to characterize and model the disturbances that will appear. Amongst the different physical effects that will appear onboard, temperature fluctuations in the Electrode Housing (EH) generate disturbances on the interferometer (IFO) readouts, therefore they must be known and controlled. Consequently, a simulator of the whole LPF is being developed to provide a validation tool for the mission operations tele-commanding chain, as well as for a deeper understanding of the underlying physical processes happening in the LTP (LISA Technology Package), the instrument hosting the Test Masses. In this study, the whole algorithm required to calculate the forces and torques on the Test Masses due to the activation of the different LTP control heaters is detailed. More specifically, transfer functions relating heat input signals to temperature increments on the Test Masses (TMs) in the LTP frequency band, from 1 mHz to 30 mHz, are determined. Following, the EH environment is studied and discretised to calculate the forces and torques that appear through thermal effects (radiometer effect, radiation pressure effect, etc). Finally, the algorithm is implemented and some experiments from the EMP (Experiment Master Plan) are simulated to evaluate the associated dynamical effects on the Test Masses. A complete thermal model of the entire LPF spacecraft plus payload, elaborated and maintained at European Space Technology Centre (ESTEC), was used to obtain temperature distributions in response to heat inputs at prescribed spots (heaters).

### Jet energy loss in the quark-gluon plasma by stream instabilities

Status: defended (17/02/2011)
Student: Gonzalez-Solis, S
Supervised by: Cristina Manuel Hidalgo
University: Universitat Autònoma de Barcelona

We study the evolution of the plasma instabilities induced by two jets of particles propagating in opposite directions and crossing a thermally equilibrated non-Abelian plasma. In order to simplify the analysis we assume that the two jets of partons can be described with uniform distribution functions…
Status: defended (17/02/2011)
Student: Gonzalez-Solis, S
Supervised by: Cristina Manuel Hidalgo
University: Universitat Autònoma de Barcelona

We study the evolution of the plasma instabilities induced by two jets of particles propagating in opposite directions and crossing a thermally equilibrated non-Abelian plasma. In order to simplify the analysis we assume that the two jets of partons can be described with uniform distribution functions in coordinate space and by Gaussian distribution functions in momentum space. We find that while crossing the quark-gluon plasma, the jets of particles excite unstable chromomagnetic and chromoelectric modes. These fields interact with the particles (or hard modes) of the plasma inducing the production of currents; thus, the energy lost by the jets is absorbed by both the gauge fields and the hard modes of the plasma. We compare the outcome of the numerical simulations with the analytical calculation performed assuming that the jets of particles can be described by a tsunami-like distribution function. We find qualitative and semi-quantitative agreement between the results obtained with the two methods

### Propietats del sistema binari eclipsant V402 Lac

Status: defended (28/01/2010)
Student: Enrique Herrero Casas
Supervised by: Jordi C.; Francesc Vilardell Sallés; Ignasi Ribas Canudas
University: Universitat de Barcelona

Eclipsing binary (EB) systems showing double lines in their spectra are excellent sources of knowledge about structure and evolution of stars. The analysis of photometric and spectroscopic data in such double systems provides very accurate values for the absolute properties of both stars, as well as…
Status: defended (28/01/2010)
Student: Enrique Herrero Casas
Supervised by: Jordi C.; Francesc Vilardell Sallés; Ignasi Ribas Canudas
University: Universitat de Barcelona

Eclipsing binary (EB) systems showing double lines in their spectra are excellent sources of knowledge about structure and evolution of stars. The analysis of photometric and spectroscopic data in such double systems provides very accurate values for the absolute properties of both stars, as well as clues about their internal structure, their formation process and the possible existence of other bodies altering their motion. V402 Lac is a V=6.7 mag binary system with two B9 type stars at a distance of 240 pc from the Sun, classified as an Algol-type EB since Hipparcos observations. In our work we are using light curves and radial velocity data in order to obtain the parameters of the binary system through an analysis with the Wilson-Devinney (WD) code. The first results, using independently the two types of data, show a clear discrepancy in some orbital parameters, which is also reproduced by new observations. Our study also revealed the existence of apsidal movement in the system, and all the times of minima are being used in order to characterize it through an O-C diagram. We are dealing with a very interesting EB with no solution for the moment. The photometrical observations scheduled for late 2010 can be decisive to solve the orbit of the system and then be able to obtain accurate values of the physical properties of the stars.

### A New Method to Simulate Extreme-Mass-Ratio Inspirals for the Laser Interferometer Space Antenna

Status: defended (20/04/2009)
Student: Priscil·la Cañizares Martínez
Supervised by: Carlos Sopuerta
University: Universitat Autònoma de Barcelona

In this work we are going to study a model of the most promising sources of GWs for LISA. These are the systems made up of an stellar compact object (SCO), m = 1 -􀀀 5 0Msun, inspiralling into a massive black hole (MBH), M = 104 - 107 Msun. These systems are called Extreme Mass-Ratio Inspirals (EMRIs)…
Status: defended (20/04/2009)
Student: Priscil·la Cañizares Martínez
Supervised by: Carlos Sopuerta
University: Universitat Autònoma de Barcelona

In this work we are going to study a model of the most promising sources of GWs for LISA. These are the systems made up of an stellar compact object (SCO), m = 1 -􀀀 5 0Msun, inspiralling into a massive black hole (MBH), M = 104 - 107 Msun. These systems are called Extreme Mass-Ratio Inspirals (EMRIs) due to the mass ratios involved are in the range q = m/M = 10-7 -􀀀  10-3.

### X/Gamma-Ray spectroscopy signal processor using LabView

Status: defended (07/02/2008)
Student: Nil García Garcia
Supervised by: Margarita Hernanz Carbó; José Manuel Álvarez Pastor
University: Universitat Politècnica de Catalunya

X/Gamma-Ray spectroscopy signal processor using LabView
Status: defended (07/02/2008)
Student: Nil García Garcia
Supervised by: Margarita Hernanz Carbó; José Manuel Álvarez Pastor
University: Universitat Politècnica de Catalunya

X/Gamma-Ray spectroscopy signal processor using LabView

### Design, development, and field testing of a precise, ruggedized, autonomous, and low-cost GPS system for polar environments

Status: defended (17/01/2008)
Student: Ismael González Flores
Supervised by: Pedro Elosegui Larrañeta
University: Universitat Politècnica de Catalunya

Glaciers undergo a dynamic glacial response to changing climate conditions. This response of glaciers is critically important, but poorly understood. In order to improve the understanding of glacier dynamics, a high spatio-temporal resolution GPS network has been designed to monitor a glacier. It will…
Status: defended (17/01/2008)
Student: Ismael González Flores
Supervised by: Pedro Elosegui Larrañeta
University: Universitat Politècnica de Catalunya

### Disseny i evaluació d’algorismes de navegació i control per al vol de satèl.lits en formació

Status: defended (05/07/2007)
Student: Laura Perea Virgili
Supervised by: Pedro Elosegui Larrañeta
University: Universitat de Barcelona

Disseny i evaluació d’algorismes de navegació i control per al vol de satèl.lits en formació Aquesta tesis consta de dos treballs: The Kalman Filter (includes: "Nonlinearity in Sensor Fusion: Divergence Issues in EKF, modified truncated GSF, and UKF") La navegaci´o relativa t´ıpicament…
Status: defended (05/07/2007)
Student: Laura Perea Virgili
Supervised by: Pedro Elosegui Larrañeta
University: Universitat de Barcelona

Disseny i evaluació d’algorismes de navegació i control per al vol de satèl.lits en formació

Aquesta tesis consta de dos treballs:

The Kalman Filter (includes: "Nonlinearity in Sensor Fusion: Divergence Issues in EKF, modified truncated GSF, and UKF")

La navegaci´o relativa t´ıpicament utilitza filtres recursius per usar i combinar diferents t´ıpus de dades (i.e. distancia i angle) provinents de sensors amb nivells de precisi´o molt diferents per a estimar els vectors d’estat dels vehicles en temps (quasi-)real. La tendencia del Extended Kalman Filter a divergir sota aquestes condicions s’ha vingut estudiant i documentant des de fa diversos anys.
En aquest treball, reproduim la demostraci´o de com el filtre seq¨uencial optim sota condicions de linealitat ´es el filtre de Kalman. A partir d’aquest filtre derivarem el filtre extes (EKF en les seves sigles en angles) utilitzant aproximacions lineals als models. Com a aplicaci´o a un problema no lineal, utilitzarem una simplificaci del problema de la navegaci´o relativa i veurem com, sota una gran diversitat de configuracions, el filtre EKF divergeix. Veurem tamb´e com altres filtres no lineals com el filtre de segon ordre de Gauss i el filtre “unscented” tamb´e poden portar a solucions erronies. Per a finalitzar aquest treball, mostrarem una serie de modificacions a aquests filtres que milloren les prestacions de manera substancial mantenint el cost computacional dels filtres originals.

Application of Cucker-Smale control law to flight formations with the particular application to DARWIN mission transfer orbit

Based on the work performed by S. Smale and F. Cucker on flocking algorithms, we designed a spacecraft control law for autonomous formation acquisition and formation keeping. As a result of applying this control law, the formation orbits as a rigid body driven by the dynamics of its baricenter.
As an application, we used this model to the transfer in loose formation of a constellation of spacecraft that follows a natural transfer trajectory to a libration point orbit, as it is suggested for the Darwin mission. The performances of Smale-Cucker control law has been characterized and compared to the Zero Relative Radial Acceleration Control (ZRRAC) in terms of the energy cost required for this transfer and the maximum separation of the spacecrafts with respect to the reference orbit.

### Long distance test of the gamma-ray diffraction lens CLAIRE

Status: defended (24/10/2005)
Student: José Manuel Álvarez Pastor
Supervised by: Margarita Hernanz Carbó
University: Universitat Autònoma de Barcelona

Long distance test of the gamma-ray diffraction lens CLAIRE
Status: defended (24/10/2005)
Student: José Manuel Álvarez Pastor
Supervised by: Margarita Hernanz Carbó
University: Universitat Autònoma de Barcelona

Long distance test of the gamma-ray diffraction lens CLAIRE

### Sea roughness and altimetry using GPS reflections

Status: defended (12/07/2005)
Student: Benjamín Garzón
Supervised by: Antonio Rius Jordán
University: Universitat Politècnica de Catalunya

The knowledge of ocean characteristics and a better understanding of sea physics are of unquestionable interest, not only on scientific grounds, but because of their connection to global meteorology and the impact of this on human lives. Research of such complex matters demands extensive data collection,…
Status: defended (12/07/2005)
Student: Benjamín Garzón
Supervised by: Antonio Rius Jordán
University: Universitat Politècnica de Catalunya

The knowledge of ocean characteristics and a better understanding of sea physics are of unquestionable interest, not only on scientific grounds, but because of their connection to global meteorology and the impact of this on human lives. Research of such complex matters demands extensive data collection, since the phenomena object of study might take place over very wide spatial and time ranges. The development of remote sensing techniques alongside space technology has made possible the availability of data on a global scale and improvements in computing have had strong repercussions on the processing of the acquired observations, fostering the growth of these disciplines.

The creation of the Global Positioning System entailed the deployment of a net of satellites constantly orbiting around the Earth and transmitting wellcharacterized signals that were first pointed out as sources of opportunity for remote sensing measurements in 1993 ([32]): the signals reflected off the Earth s surface would carry information about the position and constitution of the reflecting area. The concept was named PARIS (PAssive Reflectometry and Interferometry System). It was an alternative purpose of the GPS other than navigation or positioning bringing about an unprecedented source of data. In particular, oceans and seas constitute reasonably good reflecting surfaces at the wavelengths of these signals because of the dielectric properties of sea water. A new way was open for ocean research.

Since then, several laboratories and institutions have been working on the field: the Jet Propulsion Laboratory, the Goddard Space Flight Laboratory and the Langley Research Center from NASA and the Environmental Technology Laboratory (NOAA) in the USA, and the European Space Research and Technology Centre (ESTEC) from ESA in the Netherlands. The works within this discipline at IEEC started in 1997.

Any scientific venture goes through four fundamental steps, the four essential elements of the scientific method: characterization of the problem (observation and quantification), formulation of hypotheses, prediction (logical deduction from the hypotheses) and experiment. All these steps require time, effort and multitude of tasks to accomplish, and their execution leads to a further stage where the procedure starts again. The present work has to be regarded as a small contribution within the chain of activities meant to explore the way to exploit the possibilities GPS reflections offer. The goal of the project has been to ascertain the validity of a physical model (prediction / experiment) and to implement software routines that prepare the data output by a receiver of recent completion developed at IEEC, the GOLD-RT receiver, to be processed using this or an enhanced physical model. Appendix B recapitulates the main features of the GOLD-RT receiver.
Institute of Space Sciences (IEEC-CSIC)

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