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In this thesis, a joint experimental and theoretical investigation of the vector properties that describe the inelastic scattering of a diatomic radical with an atomic collision partner is presented. A particular emphasis is placed on those correlations that include the final rotational angular momentum, j', of the radical. The depolarisation of both NO(A) and OH(A) brought about through collisions with krypton has been studied, providing a measure of the j-j' correlation, where j is the initial rotational angular momentum associated with the diatom. The total depolarisation cross- sections for both collisional disorientation and disalignment have been measured using quantum beat spectroscopy, and modelled theoretically using quasi-classical trajectory (QCT) calculations. The agreement between experiment and theory for NO(A)-Kr is excellent, but is not observed for OH(A)-Kr under thermal conditions. This has been attributed to the importance of electronic quenching in OH(A)-Kr. The depolarisation cross-sections have also been determined at a higher collision energy for OH(A)-Kr where electronic quenching is less significant, and the experimental results are in better agreement with those obtained theoretically. The NO(A)-Kr depolarisation cross-sections fall with increasing rotational quantum number, N, whereas for OH(A)-Kr, they exhibit less of an N dependence. This trend is mirrored in the elastic depolarisation cross-sections, which have also been determined experimentally for OH(A)-Kr. The significantly attractive and anisotropic nature of the OH(A)-Kr potential energy surface (PES) accounts for these observations. The j-j' correlation is extended to include the initial (relative) velocity (k) in a new theoretical treatment of the k-j-j' correlation. The formalism developed is used with the results from the QCT calculations for NO(A)-Kr and OH(A)-Kr to provide further insight into the mechanism of depolarisation in the two systems. Collisions of NO(A) with krypton do not cause significant depolarisation due to their impulsive nature, and the projection of j onto the kinematic apse is conserved. In contrast, collisions of OH(A) with krypton effectively randomise the direction of j, again showing the influence of the anisotropic and attractive nature of the PES. However, the projection of j onto the kinematic apse is still conserved. The inelastic scattering of NO(X) with argon and krypton has also been investigated, using a crossed molecular beam apparatus. The initial Λ-doublet state of the NO(X) was selected using hexapole focussing, and the products of the collision detected using velocity mapped ion imaging. The state to state differential cross-sections (equivalent to the k-k' correlation, where k' is the final relative velocity) have been measured for collisions which conserve the initial spin-orbit level of the NO(X) with krypton. The same parity dependent effects were seen as have been observed previously for NO(X)-Ar. The collision induced alignment (equivalent to the k-k'-j' correlation) of NO(X) as a result of scattering with argon has also been determined experimentally. The results can be explained classically by considering the conservation of the projection of j onto the kinematic apse.

Made available in DSpace on 2016-04-27T14:31:54Z (GMT). No. of bitstreams: 1 CED - Celia Regina Teixeira.pdf: 565928 bytes, checksum: 110e6078962853736c75e6340ee95470 (MD5) Previous issue date: 2006-10-17 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study is to document, organize and understand the conception of EDUCATIONAL ASSESSMENT diffused in the academic production of the Education Post-Graduate Program: São Paulo Pontifícia Universidade Católica Syllabus between 1975 and 2000. Of the State of the Art and State of Knowledge study in the academic production, composed of doctoral theses and master s dissertations on educational assessment (1975-2000), 22 works were selected covering the conceptions of educational assessment produced in the Education Post-Graduate Program: Syllabus in the above mentioned period. The research was contextualized by outlining the setting composed of the post-graduate program and the conceptions of thesis and dissertation professor-tutors, based on a qualitative approach. Thesis and dissertation abstracts were analyzed and organized by using the following descriptors: theme, scope, highlighted aspects and contributions to the educational assessment conception. The research indicates that the Education Post-Graduate Program: Syllabus presents a significant set of production in the area of educational assessment, and it has become a national reference. It was possible to observe a movement in the educational assessment conceptions, which, having started with a measuring view, move towards an emancipatory view, which represents a pioneering mark in Brazilian assessment studies / Este estudo tem como objetivo documentar, organizar e compreender a concepção de AVALIAÇÃO EDUCACIONAL veiculada na produção acadêmica do Programa de Pós-Graduação em Educação: Currículo da Pontifícia Universidade Católica de São Paulo, no período de 1975 a 2000. A partir do estudo do Estado da Arte ou Estado do Conhecimento da produção acadêmica, constituída de teses de doutoramento e dissertações de mestrado sobre avaliação educacional (1975- 2000) foram selecionados 22 trabalhos em que estão contempladas concepções sobre avaliação educacional produzidos no Programa de Pós-Graduação em Educação: Currículo no período mencionado. A pesquisa foi contextualizada a partir do delineamento do cenário constituído pelo programa de pós-graduação e pelas concepções dos docentes-orientadores das teses e dissertações , segundo uma abordagem qualitativa. Os resumos das teses e dissertações foram analisados e organizados adotando-se como descritores: tema, abrangência, aspectos em destaque e contribuições para a concepção de avaliação educacional. A pesquisa aponta o fato de que o Programa de Pós-Graduação em Educação: Currículo apresenta um significativo conjunto de produções na área de avaliação educacional, tendo-se tornado uma referê ncia nacional. Constata -se uma trajetória das concepções de avaliação educacional que , partindo de uma visão de mensuração, encaminha-se para uma proposta emancipatória, constituindo um marco pioneiro dos estudos avaliativos brasileiros

Experience Mapping based Prediction Control (EMPC) is a new type of controller presented in literature, which is based on the concept of Human Motor Control (HMC). During the developmental phase, called the initial learning phase, the controller records the experience in a knowledge base, through online interactions with the system to be controlled. This knowledge base created using the experience maps is termed as Experience Mapped Knowledge Base (EMK). The controller envisages the development of EMK only through interaction with the system, without the need for knowledge of the detailed plant model. The EMPC controls the system through prediction of actions based on the mapped experiences of EMK. Depending on the nature of control required for the system chosen, various strategies can be used to achieve control using the EMK. The above controller has previously been utilized for motion control applications. In the present work an effort has been made to study the suitability of the EMPC for the voltage regulation of switching converters. The plant chosen for the control study is a discontinuous conduction mode (DCM) buck converter. The parameter to be monitored for the purpose of control is the load voltage. The control input from the EMPC to the converter is a duty ratio value based pulse-width modulated (PWM) signal. Two strategies of control have been proposed: steady state control and transient control. Steady state control action maintains the steady state output voltage at the required value for a given load. The transient control action is used to improve the transient performance of the system. Iterative predictive action and iterative transient actions are used to facilitate convergence of the output voltage to within the required range in presence of non-linearities and uncertainties in the system. Impulse action is introduced to further improve the transient performance of the system. The EMPC is compared a proportional-integral (PI) controller for the given DCM buck system.