Traditional methods of teaching magnetic induction with lab investigations using a battery, wire and compass are best reserved for demonstration purposes to introduce this particular topic. The modern student who sits in a physics course also lives in a world filled with an increasing number of small portable devices that will eventually be charged wirelessly using some form of magnetic induction. The topic of magnetic induction needs to be placed in the modern context it deserves since the future of transmitting power will eventually be through wireless means. The wireless power transfer kit described in this report is designed to improve student understanding and the application of magnetic induction in an engaging, relevant manner. / text

Cette thèse porte sur l'étude de la dynamique d'un film liquide mince soumis à une excitation normale à son interface. Cette situation donne lieu à des instabilités dites de Faraday qui, sous certaines conditions, conduisent à la formation de gouttes. Dans le contexte des systèmes d'injection assistée utilisés en propulsion aéronautique, il existe des situations pour lesquelles le courant gazeux n'est pas assez rapide pour éplucher efficacement le film de carburant. Dans ce cas, un forçage des instabilités de Faraday est envisageable pour produire des gouttes de caractéristiques en taille et en flux favorisant une combustion efficace. Dans cette thèse, on s'est intéressé à trois configurations : d'abord la configuration classique de Faraday : un liquide contenu dans un récipient vibrant donc sans écoulement liquide et sans cisaillement aérodynamique. Ensuite, on s'est intéressé à un film mince s'écoulant sur un plan incliné mais toujours en l'absence de cisaillement aérodynamique et enfin, un film mince s'écoulant sur un plan incliné en présence cette fois d'un cisaillement aérodynamique. Ces trois configurations ont été étudiées à travers trois outils : la stabilité linéaire, la simulation numérique directe à capture d'interface et l'approche expérimentale. Pour chaque configuration, les résultats donnés par les différents outils ont été comparés de manière conclusive.

The main aim of this thesis has been to contribute to the ongoing work with development of new diode-laser-based spectroscopic techniques and metho­do­lo­gies for sensitive detection of molecules in gas phase. The techniques under scrutiny are tunable diode laser absorption spectrometry (TDLAS) and Faraday modulation spectrometry (FAMOS). Conventional distributed-feedback (DFB) tele­communication diode lasers working in the near-infrared (NIR) region have been used for detection of carbon monoxide (CO) and temperature in hot humid media whereas a unique frequency-quadrupled external-cavity diode laser producing mW powers of continuous-wave (cw) light in the ultra violet (UV) region have been used for detection of nitric oxide (NO). A methodology for assessment of CO in hot humid media by DFB-TDLAS has been developed. By addressing a particular transition in its 2nd overtone band, and by use of a dual-fitting methodology with a single reference water spectrum for background correction, % concentrations of CO can be detected in media with tens of percent of H2O (≤40%) at T≤1000 °C with an accuracy of a few %. Moreover, using an ordinary DFB laser working in the C-band, a technique for assessment of the temperature in hot humid gases (T≤1000 °C) to within a fraction of a percent has been developed. The technique addresses two groups of lines in H2O that have a favorable temperature dependence and are easily accessed in a single scan, which makes it sturdy and useful for industrial applications. A technique for detection of NO on its strong electronic transitions by direct absorption spectrometry (DAS) using cw UV diode laser light has been deve­loped. Since the electronic transitions are ca. two or several orders of magnitude stronger than of those at various rotational-vibra­tional bands, the system is capable of detecting NO down to low ppb∙m concentrations solely using DAS. Also the FAMOS technique has been further developed. A new theoretical description expressed in terms of both the integrated line strength of the transition and 1st Fourier coefficients of a magnetic-field-modulated dispersive lineshape functions is presented. The description has been applied to both ro-vib Q-transitions and electronic transitions in NO. Simulations under different pressures and magnetic field conditions have been made that provide the optimum conditions for both cases. A first demonstration and characteri­zation of FAMOS of NO addressing its electronic transitions in the UV-region has been made, resulting in a detection limit of 10 ppb∙m. The characterization indicates that the technique can be significantly improved if optimum conditions can be obtained, which demonstrates the high potential of the UV-FAMOS technique.

Polarised synchrotron emission from the Milky Way is of interest for its role as a foreground to the polarised CMB and as a probe of the interstellar medium. The Galactic ALFA Continuum Transit Survey (GALFACTS) and the Global Magneto-Ionic Medium Survey (GMIMS) are two ongoing surveys of the diffuse polarised emission around 1.4 GHz, with wide bandwidths and high frequency-resolution. In this thesis, I use early data from GALFACTS to investigate the behaviour of polarised, diffuse Galactic synchrotron emission. I also analyse GMIMS total intensity data. I derive a rotation measure (RM) map of the GALFACTS sky using a combination of RM-synthesis and linear angle fitting, commenting on the structure of the maps in general and on specific regions in particular. Overall I find that the maps are rich in features, and probe the RM structure of the extended Galactic emission with reasonable accuracy. I also derive the Angular Power Spectrum (APS) of the polarised emission for thirty-one 15 by 15 degree subregions across the GALFACTS data. I compute the E- and B-modes (E+B) and the scalar APS of the polarised emission (PI). I parametrise the APS by fitting a power law to the data. Comparing the E+B APS to the PI APS shows that E+B is consistently steeper across the sky. The APS data is also used to estimate the level of foreground contamination of the CMB B-mode by the synchrotron emission. I find that the slope of the APS averaged over high-latitude, low-emission subregions agrees exactly with that of the Planck 30 GHz polarised emission, thus setting an upper limit to the synchrotron contamination of CMB B-modes. Finally, I evaluate the spurious, systematic, temperature zero-level offset and associated uncertainty in preliminary GMIMS total intensity maps, finding a lower limit of ±0.26 K. I also make spectral index maps made using the GMIMS data and the Haslam et al. (1982) 408 MHz map, improving upon previous spectral index maps in the literature.

Alors qu'il est bien connu que le phénomène d'instabilité de Faraday est une manifestation d'ondes de gravité capillaire, son comportement lorsque les effets capillaires et gravitationnels disparaissent reste inexploré théoriquement et expérimentalement. Une étude expérimentale et théorique détaillée est réalisée pour comprendre la physique de ce phénomène dans une petite cavité rectangulaire où la proximité des murs entraîne des contraintes considérables sur les parois latérales. Un couple de liquides binaires est utilisé avec une faible tension interfaciale pour une interface presque plate. Le contrôle thermique de ce système de fluide est utilisé pour diminuer la force capillaire et d’étudier ainsi les instabilités de Faraday dans les fluides miscibles où la tension interfaciale s’annule. Afin de prendre en compte les effets gravitationnels, l'expérience a été réalisée dans des campagnes de vols paraboliques. Pour l'approche théorique, une analyse de stabilité linéaire est effectuée à l'aide d'équations de Navier-Stokes dans un système de fluide visqueux incompressible et newtonien. Ceci est réalisé grâce à une méthode de Fourier-Floquet résultant en un problème aux valeurs propres. Les comparaisons montrent des différences non négligeables. Les équations sont ensuite résolues en incluant des effets d'amortissement visqueux pour compenser les contraintes des parois latérales. Les fluides binaires ont fourni une option commode pourchanger le coefficient de tension interfaciale en augmentant la température jusqu’à la température critique, ce qui a permis de passer d’un système de fluides non miscibles à celui des fluides miscibles tout en restant au-dessous de la température d’ébullition. Le taux d'amortissement visqueux linéaire est mesuré expérimentalement. La correction des calculs théoriques en prenant en compte le taux d'amortissement visqueux a permis une amélioration nette des résultats et donc de mieux comprendre la prédiction de l'amplitude critique expérimentale pour les modes sous-harmonique et harmonique. / While it is well known that the phenomenon of Faraday instability is a manifestation of vibrational acceleration, its behaviour when both the capillary and gravitational effects vanish, remains unexplored theoretically and experimentally. A detailed experimental and theoretical study is performed to understand the physics of this phenomenon in small rectangular geometry where the proximity of wall results in considerable sidewall stresses. A novel binary liquids system is utilized with low interfacial tension for a near flat interface. Thermal control of fluid system is utilized for achieving reduction in capillary force with study of miscible fluids where interfacial tension reduces to almost zero. In order to discriminate between gravity and capillarity effects, experiments were performed in parabolic flight campaigns. . For the theoretical approach a linear stability analysis is performed through Navier-Stokes equations in a Newtonian incompressible viscous fluid system. This is achieved through a Fourier Floquet method resulting into an eigenvalue problem. Equations are solved by including viscous damping effects for compensating sidewall stresses. Experimentally binary fluids provided a convenient option of changing the coefficient of interfacial tension by temperature control and going through immiscible to miscible system without change of liquid charge. Viscous damping rate is determined experimentally by measuring the linear damping rate. The correction in the theoretical calculations with the viscous damping rate helped in achieving a better understanding of the prediction of the experimental critical amplitude for sub-harmonic and harmonic modes.

Abstract In this thesis nuclear magnetic resonance (NMR) and magneto-optical rotation (MOR) parameters are investigated for water, paying special attention to the effect of solvation from gaseous to liquid phase. Nuclear magnetic shielding and quadrupole coupling tensors of NMR spectroscopy are studied for gaseous and liquid water. Liquid state is modelled by a 32-molecule Car-Parrinello molecular dynamics simulation, followed by property calculations for the central molecules in clusters cut out from the simulation trajectory. Gaseous state is similarly represented by a one-molecule simulation. Gas-to-liquid shifts for shielding constants obtained this way are in good agreement with experiments. To get insight into the local environment and its effect on the properties the clusters are divided into groups of distinct local features, namely the number of hydrogen bonds. The analysis shows in detail how the NMR tensors evolve as the environment changes gradually from the gas to liquid upon increasing the number of hydrogen bonds to the molecule of interest. The study sheds light on the usefulness of NMR experiments in investigating the local coordination of liquid water. To go a bit further, the above mentioned NMR parameters along with the spin-spin coupling constant are examined for water dimer in various geometries to have insight into solvation and hydrogen bonding phenomena from bottom to top. Characteristic changes in the properties are monitored as the geometry of the dimer is systematically varied from very close encounter of the monomers to distances and orientations where hydrogen bonding between monomers ceases to exist. No rapid changes during the hydrogen bond breaking are observed indicating that the hydrogen bonding is a continuous phenomenon rather than an on-off situation. However, for analysis purposes we provide an NMR-based hydrogen bond definition, expressed geometrically, based on the behaviour of the NMR properties as a function of dimer geometry. Our definition closely resembles widely used definitions and thus reinforces their validity. Magneto-optical rotation parameters, the nuclear spin optical rotation (NSOR) and the Verdet constant, are computed for gaseous and liquid water, in the same manner as the NMR properties above. Recent pioneering experiments including NSOR for hydrogen nuclei in liquid water and liquid xenon have demonstrated that this technique has a potential to be a useful new probe of molecular structure. We reproduce computationally, applying a first-principles theory developed recently in the group, the experimental NSOR for hydrogen nuclei in liquid water, and predict hydrogen NSOR in gaseous water along with the oxygen NSOR in liquid and gaseous water. NSOR is an emerging experimental technique that needs interplay between theory and computation for validation, steering and insight.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This article proposes a mechanical development of a dry cell in order to obtain HHO through water electrolysis. Calculations and technical specifications of the materials used for implementation are supported by mathematical, physical and chemical formulas and theories (Faraday´s Law, electrolysis process and mechanical design). The importance of mechanical design is focused on achieving efficient use of the energy provided to the cell that allows the H2 and O2 molecules to be separated without overheating the cell, evaporating the water, loss of current due to the geometry of the electrodes (Foucault Current). Moreover, choosing materials for proper implementation and physical robustness is mandatory. In addition, the mechanical design is not justified in different articles. Nevertheless, the mechanical design of the cell and the efficiency in the production of HHO are related. Therefore, the mechanical design and the calculations were performed, as well as the construction of the dry cell to obtain HHO. The results of the implementation and production were placed and compared with what theoretically the dry cell should produce from the law of Faraday. Finally, the volumetric flow of HHO obtained was 2.70 L per minute. It means a production efficiency of 98.68%. It is higher than the majority of the dry cells. / Revisión por pares

In this study, the magnetically-induced vibrations of functionalized magnetic particle suspensions were probed for the development of a novel optical spectroscopy technique. Through this work (1) the frequency-dependence of the faraday rotation in ferrofluids and (2) the extension of this system to elucidating particle size and conformation as an alternative immunossay to costly and labor/time intensive Western Blotting and ELISA has been shown. With its sensitivity and specificity, this method has proven to be a promising multi-functional tool in biosensing, diagnostic, and therapeutic nanomedicine efforts. Due to its ubiquitous nature in all optically-transparent materials, the farady rotation, or circular birefringence, was developed as a robust and sensitive nanoscale biomolecule characterization technique through Brownian relaxation studies of particle suspensions. Current efforts have shown the applicability of this phenomenon in solid, pure liquid, and colloidal samples as well as simultaneous advancements of magnetic nanoparticle research in the magnetometric and magneto-optical regimes. By merging these two fields, a clinically relevant spectroscopy (fd-FRS, Frequency Domain Faraday Rotation Spectroscopy) was developed based on a newly revised model stemming from Debye relazation theory. Through this work, an optical bench with a variable permeability core electromagnet and a frequency-domain lock-in amplifier setup (DC to 20 kHz) have been used to distinguish between Fe3O4-core nanoparticles with functionalization layers of PEG4/PEG8 polymer with future applications involving the Anti-BSA/BSA antibody/antigen couple. Particle concentrations down to 500 nM (magnetic nanoparticles) and 0.01 Volume % (magnetic beads) were studied with diameters ranging from 200 nm to 1μm. currently, the characteristic peak corresponding to the out-of-phase relazation of the suspended particles has been elusive, despite a wide particle size distribution and the use of a balanced photodetector. Future work will involved highly monodisperse samples, faster scan times, and thermal characterization applications of fs-FRS.

In recent years, spin relaxation, injection, and manipulation in semiconductors have attracted considerable interest because of several potential applications in "spintronic" devices and the necessity to understand and control spin-based phenomena. In light of the growing interest in spin-related phenomena and devices, there is now renewed interest in the science and engineering of narrow gap semiconductors (NGS). NGS based heterostructures are particularly interesting for spintronic applications due to their large spin-orbit coupling, which leads to considerable zero-field spin splitting. NGS are also candidates for electronic applications, such as high-speed and low-power microprocessors; as reported recently by Intel. Furthermore, as switching rates in electronic devices are pushed to even higher frequencies, it is important to understand dynamics in semiconductors such as NGS on femtosecond time-scales. In this thesis, time-resolved studies of magnetic and non-magnetic NGS using ultrafast-laser spectroscopy techniques such as pump-probe spectroscopy and magneto-optical Kerr/Faraday effect, are reported. Our samples include: InSb-based quantum wells with different confinement potentials; InMnSb films, the newest III-V ferromagnetic semiconductors; and InAs films. The samples for these studies have been provided by the groups of Prof. Santos at the University of Oklahoma, Prof. Furdyna at the University of Notre Dame, and Prof. Guido at Virginia Tech. The objectives in this thesis have been to: a) understand charge/spin dynamics in NGS with novel confinement potentials, b) probe the effect of magnetic impurities on the spin/charge dynamics, and c) develop concepts for spin based device applications. Several specific questions and concepts have been addressed including: the effect of large spin-orbit interaction in NGS on the dynamics, how large Rashba spin splitting in these materials affect the spin coherence life time, and carrier/spin dynamics in ferromagnetic semiconductor structures. / Ph. D.

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