The study of arterial wave propagation is essential to understand the physiopathology of the cardiovascular system, as waves carry clinically relevant information. Impedance analysis was used for such type of studies, where results were presented in the frequency domain, but it was difficult to relate specific events to time points within the cardiac cycle. Therefore, a mathematical tool called wave intensity analysis was developed, initially using measurements of pressure and velocity (PU approach). However, the need to acquire such measurements in a non-invasive, direct and simultaneous fashion led to the development of the DU approach, a type of wave intensity analysis carried out using vessel diameter and flow velocity waveforms, thus giving up the pressure measurement. It is the only available technique, at present, able to extract wave intensity information without relying on distally recorded pressure measurements and on non-simultaneous recordings. Due to its non-invasive nature for collecting the required measurements, this technique has a potential use in clinical and research settings to investigate physiological changes under rapid perturbations, such as the ones introduced by exercise. In this thesis, the DU approach is performed by only using an ultrasound device and to extract information about cardio-arterial interaction in the human common carotid artery. In the first experimental chapter of this thesis, a reproducibility study of common carotid DU-derived wave intensity parameters was conducted on a healthy young cohort, both at rest and during exercise (semi-recumbent cycling). Carotid diameter and blood flow velocity features, as well as wave intensity parameters such as forward compression, backward compression and forward expansion wave peaks and energies, were overall fairly reproducible. In particular, diameter variables exhibited higher reproducibility and lower dispersion than corresponding velocity variables, whereas wave intensity energy variables exhibited higher reproducibility and lower dispersion than corresponding peaks. Local wave speed, calculated via lnDU-loop, a technique based only on local measurements of diameter and velocity and often associated with the DU approach, was also reproducible. It is possible to conclude that the DU-derived wave intensity analysis is reliable both at rest and during exercise. In a subsequent study, DU-derived wave intensity analysis was performed on a young trained cohort to investigate the contribution of cardiac and peripheral vascular alterations to common carotid wave intensity parameters, under rapid physiological perturbations, such as semi-recumbent cycling at incremental workrates, and subsequent recovery. Judging by the increase in local wave speed, the common carotid artery stiffened substantially as workrate increased whilst peak and energy of the forward and backward compression waves also increased, due to enhanced ventricular contractility, which was associated with larger reflections from the cerebral microcirculation and other vascular beds in the head. However, the reflection indices remained unchanged during exercise, highlighting that the increased magnitude of reflections is mainly due to the enhanced contractility, rather than changes in vascular resistance, at least at the carotid artery in young healthy individuals. The forward expansion wave increased during exercise, as the left ventricle actively decelerated blood flow in late systole, potentially improving filling time during diastole. In the early recovery, the magnitude of all waves returned to baseline value. Finally, the X wave, attributed to the reflection of the backward compression wave, had a tendency to increase during exercise and to return to baseline value in early recovery. A further development of wave intensity analysis came with the reservoir-wave approach, able to separate, from the pressure and velocity waveforms, the component solely due to the reservoir volume, for the correct evaluation of backward- and forward-travelling waves. A number of issues, however, still remains, involving specifically the lack of consensus over the fitting technique and over the value of the asymptotic pressure value (P ∞),used for the determination of the reservoir waveform. Therefore, to give a contribution to the debate involving the more correct model for the pressure and velocity reservoir-wave approach, a study aimed to investigate various common carotid hemodynamic and wave intensity parameters, using different fitting techniques and values of P ∞ currently available in literature, was performed and described in the last chapter of this thesis. The study demonstrated that different fitting method and values of P ∞ could bring significant variations in values and trends of hemodynamic and wave intensity parameters. However, despite the changes in the shape of the reservoir pressure waveform, its peak and integral with respect to time tended to remain constant. This is an important feature, because both reservoir peak pressure and its integral have been used in clinical settings for the calculation of diagnostic indicators. The reservoir and excess velocity peaks, instead, changed more significantly. This outcome, together with the concomitant substantial change in excess pressure peak and integral, may greatly affect wave intensity parameters. Wave intensity parameters were, in fact, significantly more sensitive to fitting techniques and values of P ∞ than pressure parameters. Finally, the wave speed did not substantially change, leading to the conclusion that the calculation of local vessel distensibility and/or compliance, when calculated from the excess components of the waveforms, seemed insensitive to fitting techniques and values of P ∞.

Baeyer-Villiger oxidation of 1-methylpentacyclo[5.4.0.02,6.03,10.05,9] undecane-8,11-dione, performed by using m-chloroperbenzoic acid in 1:1 molar ratio, resulted in the formation of monolactone. The corresponding dilactone, was synthesized by reacting 1-methyl-PCU-8,11-dione with m-chloroperbenzoic acid in 1:2 molar ratio. 6-Methyl-1,4,4a,8a-tetrahydro-1,4-methanonaphthalene-5,8-dione was converted into the corresponding exo-6,7-monoepoxide via treatment with 30% aqueous hydrogen peroxide. Epoxidation of this monoepoxide by using m-chloroperbenzoic acid afforded the corresponding bis-epoxide. Ceric ammonium nitrate (CAN) promoted oxidation of 1-methyl-PCU-8,11-dione afforded "methylated lactones" and a "methylated alkene."

Made available in DSpace on 2014-12-17T14:55:24Z (GMT). No. of bitstreams: 1 FlavioMCBA_capa_ate_pag14.pdf: 7935796 bytes, checksum: 6c2f3a3c824a915c716376ff053cdb86 (MD5) Previous issue date: 2004-12-17 / This dissertation dea1s with the active magnetic suspension controI system of an induction bearingIess motor configured with split windings. It analyses a dynamic modeI for the radial magnetic forces actuating on the rotor. From that, it proposes a new approach for the composition of the currents imposed to the machine's stator. It shows the tests accomplished with a prototype, proving the usefulness of the new actuating structure for the radial positioning controI. Finnaly, it points out the importance of adapting this structure to well-known rotational controI techniques, continuing this kind of equipment research, which is carried out at Federal University of Rio Grande do Norte since 2000 / Esta disserta??o trata do sistema de controle de suspens?o magn?tica ativa do rotor de um motor de indu??o sem mancais na configura??o com bobinado dividido. Analisa um modelo din?mico para as for?as magn?ticas radiais atuantes sobre o rotor. A partir disso, prop?e um novo esquema de composi??o das correntes impostas ao estator da m?quina. Mostra os testes realizados sobre um prot?tipo, provando a utilidade da nova estrutura de atua??o para o controle de posi??o radial. Por fim, indica a import?ncia de se adaptar esta estrutura a t?cnicas de controle rotacional consagradas, dando continuidade ao desenvolvimento da pesquisa sobre este tipo de equipamento, que ? realizada na Universidade Federal do Rio Grande do Norte desde 2000

Made available in DSpace on 2015-04-14T13:54:50Z (GMT). No. of bitstreams: 1 400074.pdf: 487514 bytes, checksum: 557d5977f0e5d94f9fa58e928beb8fdc (MD5) Previous issue date: 2008-03-03 / Esta disserta??o trata de um tipo de infer?ncia indutiva conhecida como Infer?ncia ? melhor explica??o (IME). Este ? um modo de infer?ncia que combina de modo particularmente interessante a pr?tica inferencial e explicativa. Assim, de acordo com o modelo da IME, ao fazermos infer?ncias, buscamos explica??es para as evid?ncias que dispomos, e a melhor explica??o que encontrarmos ? a mais aceit?vel, ou mesmo, a mais prov?vel de ser verdadeira. Defensores da IME como Harman e Lipton t?m sustentado que considera??es explicativas desempenham um papel central nas infer?ncias que fazemos. Dentre tais considera??es explicativas, ou virtudes explicativas, podemos citar a simplicidade, o conservadorismo, a fertilidade, a unifica??o, a analogia, etc. A dificuldade em fornecer uma justifica??o epist?mica para as virtudes explicativas tem levado muitos autores a duvidar da legitimidade da IME frente ao problema da justifica??o. Ou seja, as virtudes explicativas, sendo meramente pragm?ticas, n?o oferecem raz?es genu?nas para crer numa hip?tese. A proposta dessa disserta??o ?, num primeiro momento, fornecer uma descri??o do modelo da IME, para depois explorar as dificuldades do modelo frente ao problema da justifica??o. Particularmente, a discuss?o do status epist?mico das virtudes explicativas receber? consider?vel aten??o. Neste sentido, tamb?m ser? feita uma discuss?o sobre a import?ncia de aspectos pragm?ticos no processo de justifica??o.

Made available in DSpace on 2015-04-14T13:56:17Z (GMT). No. of bitstreams: 1 421932.pdf: 1968986 bytes, checksum: 3fba7f654b85286a3c4cfcc6affa04d2 (MD5) Previous issue date: 2010-02-25 / Novos estudos sobre os motores de indu??o multif?sicos demonstram que ? poss?vel obter um melhor desempenho em rela??o aos motores trif?sicos, como, por exemplo, em rela??o a pot?ncia, ao torque e toler?ncia a falhas. Com a larga utiliza??o de inversores CC-CA no acionamento de m?quinas de indu??o, a utiliza??o de m?quinas multif?sicas em aplica??es que necessitem elevado desempenho tornou-se vi?vel economicamente. O controle por orienta??o direta do campo ? uma das t?cnicas de controle que propiciam uma boa resposta em m?quinas de indu??o com resposta din?mica compar?vel a das m?quinas CC. Nesta t?cnica de controle ? necess?rio medir ou estimar o fluxo do rotor para desacoplar as malhas de fluxo e torque. Esta disserta??o de mestrado apresenta o projeto de um observador robusto n?o-linear para estimar o fluxo do rotor em m?quinas de indu??o pentaf?sicas empregando o modelo desacoplado do primeiro e terceiro harm?nicos, recentemente desenvolvido para m?quinas pentaf?sicas, admitindo varia??es no valor da resist?ncia do rotor e dist?rbios de carga. A sintonia dos par?metros do observador ? feita atrav?s de um problema de otimiza??o convexa sujeito a restri??es em termos de desigualdades matriciais lineares (LMIs). O observador proposto ? avaliado mediante v?rios ensaios por simula??o.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2016-01-06T17:10:49Z No. of bitstreams: 1 DIS_PABLO_FERNANDO_CAMPOS_PIMENTEL_COMPLETO.pdf: 457041 bytes, checksum: b3767810998753faabb48ba36ef282e7 (MD5) / Made available in DSpace on 2016-01-06T17:10:49Z (GMT). No. of bitstreams: 1 DIS_PABLO_FERNANDO_CAMPOS_PIMENTEL_COMPLETO.pdf: 457041 bytes, checksum: b3767810998753faabb48ba36ef282e7 (MD5) Previous issue date: 2015-10-30 / The purpose of this paper is to present a possible reidian theory for a justification to the problem of induction from its two major writings, namely, "An Inquiry into the Human Mind on the Principles of Common Sense" 1764 and "Essays on the Intellectual Powers of Men" of 1785. Thus, appear quite subtle conception of Thomas Reid about "Problem of Induction", which is primarily discussed in the Inquiry, however, they appear quite important approaches and crucial also in Essays. It should not be forgotten that while the reidiana theory of induction is emerging, a debate and an analysis will be made by Reid in his great contemporary Hume. The importance of Hume's inclusion is indisputable because it has been Reid's time, and also by the contours of his thought about inductive reasoning and how Reid understands and, in a way, goes further. Therefore, some chapters will work with the problem of induction in the two respective works of Reid, HMI and EIP. It will also be an analysis of what was written about the induction and other peripheral issues in Reid, the other researchers. What conclusions Reid comes in and another work, and realize what critics synthesized his thinking in this respect, namely with regard to induction. / O objetivo do presente trabalho ? apresentar uma poss?vel teoria reidiana para uma justifica??o ao problema da indu??o a partir de seus dois grandes escritos, a saber, o ?An Inquiry into the Human Mind on the Principles of Common Sense? de 1764 e o ?Essays on the Intellectual Powers of Men? de 1785. Desse modo, surgir? de forma bastante sutil a concep??o de Thomas Reid acerca do ?Problema da Indu??o?, o qual ? discutido primeiramente no Inquiry, no entanto, aparecem abordagens bastante importantes e cruciais tamb?m no Essays. N?o deve ser esquecido que ao passo que a teoria reidiana da indu??o vai emergindo, um debate e uma an?lise v?o sendo feitos por Reid em seu grande contempor?neo Hume. A import?ncia da inser??o de Hume ? indiscut?vel pelo fato de este ter sido do tempo de Reid, e, tamb?m, pelos contornos de seu pensamento acerca do racioc?nio indutivo e como Reid o interpreta e, de certo modo, vai al?m. Deste modo, alguns cap?tulos trabalhar?o com o problema da indu??o nas duas respectivas obras de Reid, IHM e EIP. Tamb?m ser? feita uma an?lise do que foi escrito acerca da indu??o e outros assuntos perif?ricos em Reid, da parte de outros pesquisadores. A que conclus?es Reid chega numa e noutra obra, e perceber o que os cr?ticos sintetizaram de seu pensamento nesse aspecto, a saber, no que tange ? indu??o.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-12-12T18:05:10Z No. of bitstreams: 1 AdjairFerreiraBarrosFilho_TESE.pdf: 9926886 bytes, checksum: 1d2dea348ca690f1fa1fc74730374929 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-12-13T19:41:36Z (GMT) No. of bitstreams: 1 AdjairFerreiraBarrosFilho_TESE.pdf: 9926886 bytes, checksum: 1d2dea348ca690f1fa1fc74730374929 (MD5) / Made available in DSpace on 2017-12-13T19:41:36Z (GMT). No. of bitstreams: 1 AdjairFerreiraBarrosFilho_TESE.pdf: 9926886 bytes, checksum: 1d2dea348ca690f1fa1fc74730374929 (MD5) Previous issue date: 2017-10-09 / Esta tese tem como objetivo o estudo e a constru??o de um prot?tipo de motor de indu??o trif?sico de pequenas dimens?es (28,6 mm de di?metro externo e 15 mm de altura), com o rotor externo do tipo gaiola de esquilo sendo utilizado como motor-mancal. Esse estudo iniciou utilizando um motor Brushless convencional e que foi adaptado para funcionar como motor de indu??o com rotor externo. O motor de indu??o sem mancais utiliza a configura??o de bobinado dividido para conseguir o posicionamento radial. Foram realizados estudos de simula??es utilizando o M?todo dos Elementos Finitos ? FEM mostrando efetivamente que ? poss?vel controlar a posi??o radial para manter o rotor girando. Foi constru?do e testado um primeiro prot?tipo com sucesso, para uma pot?ncia de 100 W mostrando um bom potencial para aplica??es nesta faixa de pot?ncia e tamanho, como os aplicados em sistemas de cora??o artificial. O sistema de controle foi implementado utilizando o Processador Digital de Sinais ? DSP TMS 320F28335. / This thesis aims the study and construction of a prototype of a small three-phase induction motor (28.6 mm outside diameter and 15 mm height), with the external squirrel cage-type rotor being used as a Bearingless motor. This study started using a conventional Brushless motor and was adapted to function as an external rotor induction motor. The bearingless induction motor uses the split winding configuration to achieve radial positioning. Simulation studies were performed by using the Finite Element Method (FEM), effectively showing that it is possible to control the radial position to keep the rotor spinning. A first prototype was successfully built and tested for a power of 100 W showing good potential for applications in this power range and size, such as those applied in artificial heart systems. The control system was implemented using the Digital Signal Processor - DSP TMS 320F28335.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-01-27T19:07:52Z No. of bitstreams: 1 BrunoThiagoDaSilva_DISSERT.pdf: 3671114 bytes, checksum: f178d9c8c08d268238865077f4fa6dff (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-02T22:01:51Z (GMT) No. of bitstreams: 1 BrunoThiagoDaSilva_DISSERT.pdf: 3671114 bytes, checksum: f178d9c8c08d268238865077f4fa6dff (MD5) / Made available in DSpace on 2016-02-02T22:01:51Z (GMT). No. of bitstreams: 1 BrunoThiagoDaSilva_DISSERT.pdf: 3671114 bytes, checksum: f178d9c8c08d268238865077f4fa6dff (MD5) Previous issue date: 2015-02-05 / Este trabalho foi idealizado com o objetivo de contribuir para o ensino-aprendizagem da Indu??o Matem?tica no Ensino B?sico. Divide-se em tr?s partes: na primeira, ? feita uma discuss?o da teoria com fundamenta??o matem?tica que visa subsidiar os professores com embasamento te?rico; Na segunda, ? apresentada uma proposta para Inser??o do conte?do no Ensino M?dio em que o aluno, orientado pelo professor, e a partir de realiza??o de tarefas com car?ter investigativo, deve assimilar conhecimento; Por fim, na terceira, oferecemos uma lista de aplica??es do m?todo em proposi??es da matem?tica b?sica que busca incitar o desenvolvimento de outras abordagens que podem vir a ser feitas sobre o tema ao longo do Ensino M?dio

Made available in DSpace on 2014-12-17T14:55:34Z (GMT). No. of bitstreams: 1 AdjairFBF.pdf: 1621773 bytes, checksum: a2e7e0048de8c81be0d8971f8c7dd9bf (MD5) Previous issue date: 2002-12-13 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The present work is based on the applied bilinear predictive control applied to an induction motor. As in particular case of the technique based on predictive control in nonlinem systems, these have desperted great interest, a time that present the advantage of being simpler than the non linear in general and most representative one than the linear one. One of the methods, adopted here, uses the linear model "quasi linear for step of time" based in Generalized Predictive Control. The modeling of the induction motor is made by the Vectorial control with orientation given for the indirect rotor. The system is formed by an induction motor of 3 cv with rotor in squirregate, set in motion for a group of benches of tests developed for this work, presented resulted for a variation of +5% in the value of set-point and for a variation of +10% and -10% in the value of the applied nominal load to the motor. The results prove a good efficiency of the predictive bilinear controllers, then compared with the linear cases / O presente trabalho baseia-se na aplica??o da t?cnica de controle preditivo bilinear em um motor de indu??o. O controle preditivo bilinear, caso particular do controle preditivo n?o linear, t?m despertado grande interesse, uma vez que apresenta a vantagem de ser mais simples que o n?o linear em geral e mais representativo que o linear. Um dos m?todos, aqui adotado, utiliza o modelo "quase linear por degrau de tempo" baseado no Controlador Preditivo Generalizado. A modelagem do motor de indu??o ? feita atrav?s do controle Vetorial com orienta??o dada pelo campo do rotor indireto. O sistema ? formado por um motor de indu??o de 3 HP como rotor em gaiola de esquilo, acionado por uma bancada de testes desenvolvida para esse trabalho. Foram obtidos resultados para uma vaira??o de +5% no valor do set-point e resultados para uma varia??o de +10% e -10% no valor da carga nominal aplicada ao motor. Os resultados comprovam uma boa efici?ncia dos controladores preditivos bilineares, quando comparados com os casos lineares

Made available in DSpace on 2014-12-17T15:12:16Z (GMT). No. of bitstreams: 1 RicardoGAP_DISSERT.pdf: 757603 bytes, checksum: bfeae294ee68b7c0f314886fbbd624fb (MD5) Previous issue date: 2012-10-02 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The following work is to interpret and analyze the problem of induction under a vision founded on set theory and probability theory as a basis for solution of its negative philosophical implications related to the systems of inductive logic in general. Due to the importance of the problem and the relatively recent developments in these fields of knowledge (early 20th century), as well as the visible relations between them and the process of inductive inference, it has been opened a field of relatively unexplored and promising possibilities. The key point of the study consists in modeling the information acquisition process using concepts of set theory, followed by a treatment using probability theory. Throughout the study it was identified as a major obstacle to the probabilistic justification, both: the problem of defining the concept of probability and that of rationality, as well as the subtle connection between the two. This finding called for a greater care in choosing the criterion of rationality to be considered in order to facilitate the treatment of the problem through such specific situations, but without losing their original characteristics so that the conclusions can be extended to classic cases such as the question about the continuity of the sunrise / O seguinte trabalho consiste na interpreta??o e an?lise do problema da indu??o sob uma vis?o fundamentada em teoria de conjuntos e teoria de probabilidades como base para a solu??o de suas implica??es filos?ficas negativas relativas aos sistemas de l?gica indutiva de maneira geral. Devido ? import?ncia do problema e aos desenvolvimentos recentes nos referidos campos de conhecimento (in?cio do s?culo 20), bem como ?s rela??es vis?veis entre eles e o processo de infer?ncia indutivo, tem-se aberto um campo de possibilidades relativamente inexplorado e promissor. O ponto-chave para o estudo consiste na modelagem do processo de aquisi??o de informa??o usando conceitos de teoria de conjuntos, seguido por um tratamento usando teoria de probabilidades. Ao longo do estudo foi poss?vel identificar, como obst?culos principais ? justifica??o probabil?stica, tanto o problema da defini??o do conceito de probabilidade quanto do de racionalidade, al?m da sutil conex?o entre ambos. Essa constata??o permitiu um maior cuidado na escolha do crit?rio de racionalidade a ser considerado no intuito de viabilizar o tratamento do problema por meio de situa??es-exemplo espec?ficas, mas sem a perda de suas caracter?sticas originais, de modo que as conclus?es obtidas possam ser estendidas a casos cl?ssicos como o relativo ? d?vida sobre a continuidade do nascer do sol