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1
Kachkachi, Noreddine. "Spectromètre RQN à base d’un SoC-FPGA : Conception numérique, vérification fonctionnelle et validation expérimentale". Electronic Thesis or Diss., Université de Lorraine, 2024. http://www.theses.fr/2024LORR0053.
Testo completoAbstract (sommario):
La Résonance quadrupolaire Nucléaire (RQN) est une technique de spectroscopie radio fréquence très utile pour l'identification non invasive et l'analyse de produits chimiques. Cependant cette technique souffre de plusieurs problèmes, notamment de la faible sensibilité et pose beaucoup de défis quand à la conception de l'instrumentation RQN. Afin de relever ces défis techniques et d'améliorer davantage les performances, nous proposons de développer ici, une nouvelle approche qui consiste en la numérisation et l'optimisation de l'architecture électronique en vue d'améliorer la sensibilité. Ainsi, j'ai réalisé dans le cadre de cette thèse, la conception, la vérification fonctionnelle ainsi que la validation expérimentale d'un spectromètre RQN à base d'un SoC-FPGA où l'essentiel de la fonctionnalité matérielle et logicielle est intégré sur une seule puce. Les modules que j'ai conçus et intégrés sur le SoC-FPGA sont: un générateur d'impulsions haute résolution, un module d'acquisition entièrement numérique avec un traitement de signal temps réel et FID stocké sur mémoire externe DDR, un module d'émission numérique entièrement contrôlé et un module de débogage. En plus de la partie logique programmable, j'ai développé et intégré sur le processeur embarqué du SoC-FPGA deux applications Linux pour piloter le spectromètre. La conception de cette architecture, numérique et optimisée, a permis ainsi de se doter d'un nouveau spectromètre de performances et de fonctionnalités remarquables par rapport à l'état de l'art et par rapport aux spectromètres portables commerciaux. La miniaturisation et la numérisation ont permis aussi de réaliser la compacité du système et ainsi d'ouvrir la porte à de nouvelles applications industrielles. En plus, la réalisation de cette nouvelle architecture à base de SoC-FPGA, a apporté une amélioration de la sensibilité grâce à une meilleure immunité aux bruits et à une chaîne d'acquisition entièrement numérique avec un traitement de signal performant. Le spectromètre réalisé a été testé avec succès sur plusieurs échantillons de référence ainsi que sur des échantillons à applications pharmaceutiques tels que le paracétamol et le nitroprussiate de sodiumNuclear Quadrupolar Resonance (NQR) is a radio frequency spectroscopy technique that is very useful for non-invasive identification and analysis of chemical products. However, it suffers from low sensitivity which makes its instrumentation very challenging. In order to tackle these challenges and enhance the performances, especially sensitivity,we present in this thesis a solution which consists in a SoC-FPGA based compact spectrometer, where all the major digital hardware and software modules are integrated on a single System On Chip, including : a high pulse width resolution pulse programmer, a fully controllable transmitter, an acquisition module with real time digital signal processing, and storage of the acquired signal in an external memory, and a hardware debugger, in addition to embedded Linux applications that drive the spectrometer functionalities. This digital integration and miniaturisation brought noticeable performances of the spectrometers' overall functionality, especially in terms of sensitivity and portability. The designed spectrometer was successfully tested on several representative samples
2
Tingle, Jeremy Mark. "NMR imaging : instrumentation and techniques". Thesis, University of Surrey, 1992. http://epubs.surrey.ac.uk/843892/.
Testo completoAbstract (sommario):
This thesis presents three original contributions to the field of Nuclear Magnetic Resonance (NMR): The experimental framework and analysis for the measurement of a new imaging parameter to describe perfusion; The measurement and analysis of magnetic field inhomogeneity and a practical correction system for their reduction; A novel system for the synchronous control of NMR experiments based on the microprogrammed concept. The thesis begins with an introduction to the theory of NMR. The application of NMR to imaging is also introduced with emphasis on the techniques which developed into those in common use today. Inaccurate determination of the traditional NMR parameters (T1 and T2 and the molecular diffusion coefficient) can be caused by non-diffusive fluid movement within the sample. The experimental basis for determining a new imaging parameter - the Perfusion coefficient - is presented. This provides a measure of forced isotropic fluid motion through an organ or tissue. The instrumentation required for conducting NMR experiments is described in order to introduce the contribution made in this area during this research: A sequence controller. The controller is based on the concept of microprogramming and enables completely synchronous output of 128 bits of data. The software for the generation and storage of control data and the regulation of the data to provide experimental control is microcomputer based. It affords precise and accurate regulation of the magnetic field gradients, the rf synthesizer and the spectrometer for spectroscopic and imaging applications. Fundamental to the science of NMR is the presence of a magnetic field. A detailed study of the analysis of magnetic field inhomogeneity in terms of spherical harmonics is presented. The field of a whole body imaging system with poor inhomogeneity was measured and analyzed to determine and describe the components of the inhomogeneity. Finally a description is given of the design and application of practical methods for reducing the dominant inhomogeneities.
3
Thornton, John Stephen. "Instrumentation for low cost, high resolution NMR imaging". Thesis, University of Manchester, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358563.
Testo completo
4
Markhasin, Evgeny. "High field DNP and cryogenic MAS NMR : novel instrumentation and applications". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/87469.
Testo completoAbstract (sommario):
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, February 2014.Cataloged from PDF version of thesis. "February 2014."
Includes bibliographical references.
Solid State Nuclear Magnetic Resonance (ssNMR) spectroscopy has blossomed over the last two decades. As ssNMR is progressively applied to more challenging systems, the sensitivity remains one of its major limiting factors. Gyrotron based high-field dynamic nuclear polarization (DNP) permits increasing the sensitivity of ssNMR by 1-2 orders magnitude, significantly extending the reach of ssNMR. Successful application of ssNMR/DNP at 5T and 9.4T stimulated interest to extending this technique to higher fields and new applications. Here, the progress toward this goal is presented. It has involved completion of the world highest field magic angle spinning (MAS) DNP spectrometer and a probe for 16.4T, initial DNP experiments on ¹⁷ O nuclei, variable temperature studies of a model tripeptide, and a systematic analysis of a novel approach to high efficiency RF circuit design. The extension of DNP-NMR to 16.4T has required the development of probe technology, cryogenics, gyrotrons, and microwave transmission lines. A novel DNP probe and cryogenic instrumentation permit extended operation at 85-90K and 10kHz MAS. Initial enhancements [epsilon]=-40 and further optimization of experimental conditions is underway. ¹⁷ O detected DNP-NMR of a water/glycerol glass at 5T enabled an 80-fold enhancement of signal intensities at 82K permitting ¹⁷ O- ¹H distance measurements and heteronuclear correlation experiments. Variable temperature MAS NMR studies of a model tripeptide APG in combination with cryogenic calorimetry and XRD revealed a first-order phase transition and severe attenuation of the cross polarization MAS signal in a wide temperature range due to interference between decoupling and 3-fold hopping of the Ala-CH₃ and Ala-NH₃+ groups. A new, efficient strategy for designing balanced transmission line RF circuits for MAS NMR probes based on back propagation of a common impedance node (BPCIN) is presented. In this approach, the impedance node is the sole means of achieving mutual RF isolation and balance in all channels. BPCIN is illustrated using a custom double resonance MAS probe operating at 11.7T.
by Evgeny Markhasin.
Ph. D.
5
Laurent, Guillaume. "Increasing solid-state NMR sensitivity : instrumentation, fast acquisitions and signal processing". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS183.
Testo completoAbstract (sommario):
La Résonance Magnétique Nucléaire (RMN) en phase solide souffre d’une faible sensibilité, malgré les récentes améliorations. Les approches instrumentales, d’acquisition rapide et de traitement du signal ont été examinées afin de remédier à ce défaut le plus efficacement possible. Premièrement, les microbobines (bobine en rotation à l’angle magique, MACS) ont été placées dans un rotor et couplées inductivement à la bobine de la sonde standard. Un gain en temps de ~ 5 a été obtenu sur des microquantités avec une masse m ~ 100-200 µg. Deuxièmement, le temps d’acquisition a été diminué grâce aux échos Carr-Purcell-Meiboom-Gill (CPMG) pour l’acquisition directe. Nous avons produit un programme Python pour traiter les données soit en utilisant les méthodes standard de peigne ou de superposition, soit avec une méthode de débruitage. Un gain en temps de ~ 3-100 a été possible. Troisièmement, l’échantillonnage non-uniforme (NUS) a été choisi comme un moyen de diminuer le temps d’acquisition des expériences multi-dimensionnelles. L’échantillonnage Poisson s’est avéré le meilleur choix pour limiter les artefacts, tandis que l’échantillonnage hybride s’est révélé efficace sur les spectres présentant à la fois des pics larges et fins. Un gain en temps de ~ 4 a été obtenu. Quatrièmement, les spectres ont été traités avec le débruitage par décomposition en valeurs singulières (SVD). Nous avons mis en avant une surestimation des pics gaussiens de ~ 20 %. Le seuillage automatique a été mis en place, donnant un gain en temps de ~ 2,3. Enfin, le temps de calcul a été étudié et diminué par ~ 100. Une comparaison entre les unités centrales (CPU) et les cartes graphiques (GPU) a été fournieSolid-state Nuclear Magnetic Resonance (NMR) is suffering from an intrinsic low sensitivity, despite recent improvements. Instrumentation, fast acquisition and signal processing approaches were investigated to circumvent this drawback as far as possible. Firstly, microcoils (Magic Angle Coil Spinning, MACS) were placed into rotors and inductively coupled to the standard probe coil. A time gain of ~ 5 was obtained for microquantities with a mass m ~ 100-200 µg. Secondly, acquisition time was decreased by mean of Carr-Purcell-Meiboom-Gill (CPMG) echoes for direct acquisition. Adequate processing is required to get the best enhancement from this technique. We provided a Python software to process data either using standard spikelets or superposition methods, or with a denoising method. A time gain of ~ 3-100 was possible. Thirdly, Non-Uniform Sampling (NUS) was chosen as a way to decrease acquisition time of indirect dimensions of multi-dimensional experiments. Poisson sampling revealed to be the best choice to limit artefacts, whereas hybrid sampling proved to be efficient on spectra with both broad and narrow peaks. A time gain of ~ 4 was achieved. Fourthly, spectra were processed with Singular Value Decomposition (SVD) denoising. We highlighted an overestimation of Gaussian peaks by ~ 20 %. Automatic thresholding was implemented, giving a time gain of ~ 2.3. Finally, computation time was decreased by ~ 100 by combining ‘divide and conquer’ algorithm, optimised libraries, hardware instruction calls and single precision. A comparison between Central Processing Units (CPU) and Graphical Processing Units (GPU) was provided
6
Di, Caro Domenico. "NMR measurements for hazelnuts classification". Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3113.
Testo completoAbstract (sommario):
2016 - 2017In this work, a method for the quality detection of the in-shell hazelnuts, based on the low field NMR, has been proposed. The aim of the work is to develop an in-line classification system able to detect the hidden defects of the hazelnuts. After an analysis of the hazelnut oil, carried out in order to verify the applicability of the NMR techniques and to determine some configuration parameters, the influence factors that affect these measurements in presence of solid sample instead of liquids have been analyzed. Then, the measurement algorithms were defined. The proposed classification procedure is based on the CPMG sequence and the analysis of the transverse relaxation decay. The procedure includes three different steps in which different features are detected: moisture content, kernel development and mold development. These quality parameters have been evaluated .analyzing the maximum amplitude and the second echo peak of the CPMG signal, and the T2 distribution of the relaxation decay. In order to assure high repeatability and low execution time, special attention has been put in the definition of the data processing. Finally, the realized measurement system has been characterized in terms of classification performance. In this phase, because of the reduced size of the test sample (especially for the hazelnuts with defects) a resampling method, the bootstrap, was used. [edited by Author]
XVI n.s. (XXX ciclo)
7
Pagnano, Marco Aurelio de Oliveira. "Automação de um espectrômetro por ressonância magnética nuclear pulsada". Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-19082014-101639/.
Testo completoAbstract (sommario):
Este trabalho consistiu na automação do espectrômetro de Ressonância Magnética Nuclear Pulsada existente no laboratório dos professores José Pedro Donoso e Claudio José Magon. Foram efetuados circuitos adicionais e melhorias no equipamento que eles possuíam, à nível de hardware e software. Foram construídas e programadas interfaces paralelas que ligam o microcomputador a um gerador de pulsos, fabricado pela Tecmag Inc., e a um digitalizador rápido (10 ns) Nicolet 430. O programador de pulsos pode acionar independentemente 75 linhas durante o intervalo de tempo subdividido em 2048 eventos, também independente. O software desenvolvido permite a programação de todas as linhas e eventos de forma eficiente e prática. Foi todo escrito em linguagem C, é modular, portátil, e permite a geração de seqüências de pulsos sofisticadas e também o controle da aquisição e transferência de dadosThis work describes the Project developped to automatize the pulsed nuclear magnetic resonance spectrometer housed in the laboratory of the professors José Pedro Donoso e Cláudio José Magon. To satisfy our needs we have improved their old equipment, at the level of hardware and software. Were built and programmed the parallel interface between the microcomputer and a pulse programmer made by Tecmag Inc. and with a fast digitizer (10 ns) Nicolet 430. The pulse programmer can control 75 independent output channels during 2048 time intervals. The software we developped allow us to control the whole pulse sequence on a very efficient and practical way. It was written in C-language, and provides the timing signals necessary to generate sofisticated pulse seqüencies, the data acquisition and data transfer to the host computer
8
Bays, Roland. "Instrumentation pour l'étude des propriétés optiques des tissus vivants /". [S.l.] : [s.n.], 1992. http://library.epfl.ch/theses/?display=detail&nr=1086.
Testo completo
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Rolland, Thierry. "Développement d'une instrumentation Doppler ultrasonore : application aux écoulements turbulents en hydraulique /". [S.l.] : [s.n.], 1995. http://library.epfl.ch/theses/?nr=1281.
Testo completo
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Menolfi, Christian Ivo. "Low noise CMOS chopper instrumentation amplifiers for thermoelectric microsensors /". Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13583.
Testo completo
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Rahima, Sidi-Boulenouar. "Dynamic monitoring of water status of plants in the fields under environmental stress : Design of a portable NMR and applied to sorghum". Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS081/document.
Testo completoAbstract (sommario):
Aujourd’hui, comprendre comment les plantes réagissent au stress hydrique est essentiel pour relever le défi de développer de nouveaux cultivars et de nouvelles stratégies d’irrigation, compatibles avec le maintien de la productivité des cultures sous les effets néfastes du réchauffement climatique. Dans ce contexte, l’étude des relations eau/plante présente un intérêt majeur pour la modélisation des réponses des plantes et des organes aux contraintes biotiques et abiotiques. Paradoxalement, il existe très peu de méthodes directes et non invasives pour quantifier et mesurer le niveau et le débit de l’eau dans les plantes.Dans le cadre de ce projet, nous rapportons le développement d’une méthodologie innovante basée sur la relaxation par résonance magnétique nucléaire à champ faible (RMN). Un dispositif RMN dédié pour effectuer des mesures RMN sur des plantes vivantes a été construit dans une chambre climatique qui permet un contrôle et une modification minutieuse des paramètres environnementaux pendant l’expérimentation sur des longues périodes au laboratoire. En parallèle, une imagerie RMN complémentaire à haut champ magnétique pour étudier, l’anatomie, la teneur en eau, le transport du phloéme et du xylème chez les plants de sorgho a été réalisé. La combinaison de ces approches nous permet de déterminer des biomarqueurs éco-physiologiques innovants et de concevoir de nouvelles expériences en laboratoire et même dans les champs.Un résultat particulièrement intéressant concerne l’étude de la distribution spatiale de l’eau dans les tiges (nœuds et entrenœuds) à partir de la relaxométrie RMN à faible champ et des images IRM 3D à haute résolution. La modification des paramètres de relaxation RMN au cours du cycle diurne dynamique sera présentée dans des conditions normales et en situation de stress abiotique. Une application directe permet d’extraire des biomarqueurs écophysiologiques qui permettent d’explorer et de modéliser les flux d’eau en période de stress hydrique et d’analyser leur impact sur le développement du sorgho.Notre but ultime est d’effectuer ces études RMN directement dans les champs. Ainsi, un appareil RMN portable fait maison, fonctionnant à 336 kHz est présenté. Le développement et l’optimisation de l’homogénéité d’un aimant résistif et de bobines Radio Fréquence ainsi que des séquences d'impulsions RMN, afin de respecter la polyvalence et les conditions thermiques pour maintenir la plante ,intacte sont décrits en détails. Enfin nous présenterons nos investigations menées avec ce dispositif en laboratoire, dans les serres et dans les champs de sorghoToday, understanding how plants respond to water stress is essential to meet the challenge of developing new cultivars and new irrigation strategies, consistent with the maintenance of crop productivity with the evidence of global warming. In this context, the study of plant /water relations is of central interest for modeling plant and organ responses to biotic and abiotic constraints. Paradoxically, there are very few direct and non-invasive methods to quantify and measure the level and the flow of water in plants.For this purpose, we report on the development of an innovative methodology based on low-field Nuclear Magnetic Resonance Relaxometry (NMR). A dedicated NMR device to perform NMR measurements on living plants has been built in a climatic chamber that allows a control and careful modification of environmental parameters during experimentation over reliable periods of time at the laboratory. In parallel, complementary NMR imaging at high magnetic field to study, the anatomy, water content, phloem and xylem transport in sorghum plants were performed. The combination of these approaches allows us to determine innovant eco-physiological biomarkers and to design new experiments in the laboratory and even in the fields.One particular interesting result concertns the investigation of the spatial distribution of water stems (node and inter node) from low field NMR Relaxometry and 3D high resolution MRI images. The modification of the NMR relaxation parameters during dynamic diurnal cycle will be presented in normal and abiotic stress conditions. A direct application permits to extract eco-physiological biomarkers which allows to explore and model water fluxes during water stress and to analyze their impact on the development of sorghum plant. Our ultimate goal is to perform these NMR studies directly in the fields. Thus, a home made portable NMR device, working at 336kHz(8mT) is presented. The development and optimization of the homogeneity of a resistive magnet and Radio Frequency coils, NMR pulse sequences in order to respect the versatility and thermal conditions to maintain the plant intact are described in details. Finally we will present our investigations conducted with this device in the laboratory, in the greenhouses and in sorghum fields
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Tannus, Alberto. "Desenvolvimento da tecnologia de tomografia por ressonância magnética nuclear". Universidade de São Paulo, 1987. http://www.teses.usp.br/teses/disponiveis/54/54132/tde-21052007-164959/.
Testo completoAbstract (sommario):
Neste trabalho, descrevemos o desenvolvimento do equipamento e o software necessários à implementação da técnica de obtenção de imagens por RMN. Nossos principais objetivos foram a construção de um sistema de controle e aquisição de dados que permitisse operar um espectrômetro de Fourier de RMN pulsada como um tomógrafo de RMN; por outro lado, visamos a construção de um espectrômetro que tivesse seus parâmetros facilmente reconfiguráveis pelo sistema de controle. O resultado foi um sofisticado equipamento que permite, além do proposto, trabalhar com técnicas de espectroscopia de alta resolução e espectroscopia em sólidos. Uma grande ênfase foi dada ao entendimento das técnicas De reconstrução de imagens, desde as convencionais até aquelas que constituem atualmente a fronteira de pesquisa nessa área. Os resultados obtidos com o sistema descrito são considerados bons, comparáveis aos das unidades construídas por empresas que operam comercialmente nessa área, em cooperação com centros localizados em universidades no exterior, pouco devendo a equipamentos similares (protótipos) desenvolvidos naqueles centros.We describe in this work the development of hardware and software necessary to implement the Magnetic Resonance Imaging (MRI) techniques. Our major subjects were the construction of an acquisition and control system which allowed the operation of a pulsed Fourier NMR spectrometer as a NMR Tomograph; further we oriented the developing of a NMR spectrometer whose parameters could be easily reconfigured by the controlling system. As a result we obtained a sophisticated equipment which allows, more than the proposed, working with high resolution spectroscopic techniques and spectroscopy in solids. Since the basic techniques employed in NMR and CT Tomographs are well known, a great emphasis was also given on the understanding of the image reconstruction techniques that constitutes today the frontier of research in this area. The results obtained with the system described here are considered good, comparable to the results from commercial units developed in cooperation with imaging groups located in universities abroad.
13
Fiorani, Luca. "Une première mesure lidar combinée d'ozone et de vent, à partir d'une instrumentation et d'une méthodologie coup par coup /". [S.l.] : [s.n.], 1996. http://library.epfl.ch/theses/?nr=1585.
Testo completo
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Braz, Daniel Cesar. "Instrumentação para RMN em campo externo nulo com aplicação ao estudo de ligas FeV no estado de ordenação magnética". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-22042010-160250/.
Testo completoAbstract (sommario):
Esse trabalho foi motivado pela conjugação das necessidades do Laboratório de Ressonância Magnética Nuclear com as características técnicas do autor dessa dissertação. Havia a necessidade urgente no grupo da documentação e melhoria da instrumentação e do software de processamento dos dados já desenvolvidos para a realização de experimentos de Ressonância Magnética Nuclear em campo externo nulo. Ao longo do desenvolvimento desse trabalho, verificouse a necessidade de novos desenvolvimentos, a saber: o desenvolvimento de um software para processamento dos dados e o desenvolvimento da automação do aparato de controle da temperatura dos experimentos (4,2 a 400 K). A partir do software para processamento dos dados desenvolvido em Matlab, é possível processar facilmente o sinal para reconstrução do espectro. O processamento dos dados pode ser feito por duas vias: integrando o sinal no domínio do tempo ou integrando sua Transformada Fourier (FT). Deste modo, o tempo de processamento dos dados foi consideravelmente reduzido. A automação do aparato para o controle da temperatura permite uma interação mais amigável com o sistema do criostato. Finalmente, o espectrômetro de RMN foi utilizado para o estudo de ligas de FeV na fase sigma. Esses experimentos foram realizados de modo a se observar os espectros dos núcleos de 51V (10 - 100 MHz) e suas oscilações quadrupolares em função da concentração de Fe e da temperatura. Com esse estudo, podese confirmar que os espectros são relativos aos núcleos de 51V. As intensidades das cinco linhas observadas são coerentes com as populações de átomos de V em cada um dos cinco sítios (A, B, C, D e E) cristalográficos, assim como determinado por Difração de Nêutrons. O acoplamento quadrupolar medido foi de aproximadamente 312 KHz para todos os sítios estudados.This work was motivated by the combination of the needs of the Nuclear Magnetic Resonance Laboratory with the technical features of the author of this dissertation. There was an urgent need in the group to document and improve the instrumentation and data processing software already developed to carry out the zero external magnetic field Nuclear Magnetic Resonance experiments. During the development of this work, it was verified the need for new developments, namely: development of software for data processing and development of automation of the apparatus used for the NMR experiments versus temperature. From the software developed for data processing, written in Matlab, it is easily possible processing the signal to reconstruct the spectrum. The data processing can be done in two ways: integrating the signal in the time domain or integrating its Fourier Transform. The processing time of the data was fast. The automation of the apparatus for controlling the temperature allows a more friendly interaction with the cryostat system. Finally, the NMR spectrometer was used to the study of FeV alloys in sigma phase. The experiments were performed to observe the 51V spectra (10 MHz to 100 MHz) and their quadrupolar oscillations, versus of the Fe concentration and temperature. With this study, it was possible to confirm that the spectra are relative to the 51V nuclei. The intensities of the five lines observed are coherent with the population of the V atoms in each of the Five crystallographic site (A, B, C, D e E), as determined by Neutron Diffraction. The quadrupolar couplings measured were found to be approximately 312 kHz for all sites studied.
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Andreeta, Mariane Barsi. "Programação de um sistema de controle de RF e aquisição de dados para um espectrômetro de RMN de baixo custo". Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-22052012-173456/.
Testo completoAbstract (sommario):
Este projeto teve como objetivo a construção e automatização de um espectrômetro de baixo custo que tem como principal aplicação a caracterização de meios porosos. Para realizar a caracterização de um meio poroso é necessário que o campo magnético externo aplicado não seja intenso para diminuir os problemas relacionados com a diferença de susceptibilidade magnética na interface fluido-solido. Por este motivo, foi construído um magneto resistivo de baixo campo, operando na frequência de próton de 2MHz (0.047 Tesla) e de simples design. Para manter o equipamento com custo mais baixo possível foram construídos em laboratório a fonte de alimentação do magneto, um amplificador ajustado para 2MHz e os componentes λ/4 e os softwares necessários. O software desenvolvido tem a finalidade de controlar a placa de geração e aquisição de radiofrequência que foi adquirida pela empresa Spincore, denominada RadioProcessor. Para esta finalidade optou-se pela construção de uma nova API na linguagem C++, utilizando a API original do RadioProcessor como base, de forma a montar um conjunto de funções simples e intuitivas para a utilização do espectrômetro. Além disso, foi realizada a integração de uma linguagem script à biblioteca, que dá acesso ao usuário a todas as funções básicas de programação, permitindo que um usuário com pouca habilidade de programação possa criar um programa para o controle total do equipamento de forma simples e também tornando o software maleável, sendo possível que novas funções sejam integradas. Isso abre espaço para que o equipamento possa ser utilizado para outras aplicações além das citadas anteriormente. Somada à nova biblioteca, uma interface gráfica foi desenvolvida, a qual compreende o programa de controle do equipamento e também funções para tratamento e visualização de dados, como a transformada inversa de Laplace e transformada de Fourier.The objective of this project was the assembling and automatization of a low cost NMR spectrometer for the characterization of porous media. The study of porous media through NMR spectroscopy requires a low intensity magnetic field in order to avoid the problems related to the difference of magnetic susceptibility on the fluid-solid interface. For that reason, a low field electromagnet, operating on the proton frequency of 2MHz (0.047 Tesla) and of simple design was built. As to keep all the equipment as low cost as possible, the following components were also assembled in laboratory: the magnets power supply, a 2MHz amplifier, the quarter-wave components and the necessary softwares. The goal of the software developed was to control the RF generation and acquisition board, which was acquired from the enterprise Spincore, further named RadioProcessor. To achieve this goal, it was decided the development of a new API, in the C++ language, which uses the original boards API as a base in order to assemble a group of functions that are simpler and more intuitive to the end user. In addition, a script language was integrated to the APIs library, allowing users with little programming knowledge to write a program which controls the whole equipment in an easy way and also adding flexibility to the software, as it becomes easy to add new functions. This permits that the equipment be easily changed to include other applications in the future. Finally, a graphical interface was developed, which comprehends the equipment control software and the visualization of the data.
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Chagas, Ismael Pereira. "Desenvolvimento de um fotometro portatil NIR para determinação do teor de agua no alcool combustivel e do teor de etanol na gasolina". [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250572.
Testo completoAbstract (sommario):
Orientador: Jarbas Jose Rodrigues RohwedderTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: Neste trabalho, foi desenvolvido um fotômetro NIR portátil para determinar o teor de água em álcool combustível hidratado combustível (AEHC) e o teor de etanol (Álcool etílico anidro carburente) em gasolina. Foram realizados inicialmente estudos espectroscópicos empregando um espectrofotômetro comercial para avaliar quais as melhores regiões do espectro NIR que poderiam ser empregadas para a determinação das espécies de interesse. No desenvolvimento do instrumento foram avaliados detetores baseados em um foto resistor de PbS e um fotodiodo de InGaAs. Dentre os detectores empregados o que apresentou melhores resultados foi o detector de InGaAs. Foram construídos diversos fotômetros sendo que aqueles que apresentaram as melhores performance utilizaram filtro de interferência em 1480 nm e celas cilíndricas com caminho óptico de 2 mm e 5 mm. Para o caminho óptico de 2 mm, foi utilizada como fonte de radiação uma lâmpada de 6 watts, enquanto que para a cela com 5 mm foi utilizada uma lâmpada de tungstênio de 20 watts e uma lente colimadora. Em ambos os casos, a fonte de radiação foi pulsada a uma freqüência de 25 Hz. Como transdutores de saída do instrumento foram empregados um microcontrolador PIC acoplado à um display de cristal líquido e também dois LEDs (vermelho e verde) indicando se o combustível estava dentro ou fora da especificação. O instrumento foi avaliado com amostras comerciais de álcool combustível e gasolina. Para a determinação do teor alcoólico em álcool combustível, a resposta é linear na faixa de concentração de 88 a 98% m/m, com um erro médio de 3,6 % para um total de 30 amostras analisadas, quando comparada ao seu respectivo método de referência. Na análise de amostras de gasolina foi obtida uma resposta linear para o teor de etanol entre 20 % e 30 %, com um erro médio de 3,0% para um total de 40 amostras analisadas. A ANP considera até 4% de erro médio e desta forma o instrumento classifica corretamente 100 % das amostras
Abstract: In this work a portable Near Infrared Photometer to determine the quantity of water in alcohol fuel and the quantity of ethanol in gasoline was developed. Initially, several spectroscopy analysis using a comercial spectrophotometer was made to select the best wavelenghts to determine those fuel quality parameters. The wavelengths of 1480 nm and 1920 nm were selected after preliminary study. The instrument was evaluated using two types of detectors: a PbS photoresistive detector and a InGaAs photodiode. The detector with best performance was the InGaAs photodiode. Different prototypes were built using a interference filter working in 1480 nm and path length with 2 mm and 5 mm. With the 2 mm path length was used a 6 watt tungsten lamp as radiation source and with 5 mm path length was used a 20 watts tungten lamp. This interference filter can be used to determine water in alcohol fuel and ethanol in gasoline without any changes in the instrument. The final version of the prototype showing the best results for both determinations uses a cilindric cell with 5 mm diameter and can be employed for flow or batch measurements, radiation source of a 20 watts tungsten lamp pulsed at 25 Hz and a lens to focus the infrared radiation into the detector. The output transducers of the instrument was a PIC microcontroller with a liquid crystral display and light emission diodes (LEDs) green and red. The instrument was tested using comercial fuel alcohol and gasoline samples. In the determination of water in alcohol it was obtained a linear response in the concentration range from 98 to 88 % (m/m) and in gasoline, it was 20 % to 30 %(v/v). Thirty alcohol samples were analysed showing a standard error of 3,6 % while for the gasoline, a standard error of 3,0% for a total of 40 samples analysed was found. Considering the tolerance of 4%, recommended by the National Pretoleum Agency (ANP), the instrument can classify normal and adultered samples with confidence of 100%
Doutorado
Quimica Analitica
Doutor em Quimica
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Biscegli, Clovis Isberto. "Espectrômetro para a transferência de polarização elétron-núcleo (efeito Overhauser)". Universidade de São Paulo, 1994. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-01042014-143911/.
Testo completoAbstract (sommario):
Este trabalho apresenta os detalhes da construção de um espectrômetro para a realização de experimentos de transferência de polarização elétron-núcleo (Efeito Overhauser). São também mostrados: as implementações e modificações feitas no espectrômetro de RPE existente no Laboratório de Ressonância Magnética do DFCM, os circuitos para a construção de um equipamento de RMN para operar de forma pulsado na freqüência fixa de 14 MHz, os desenhos da cavidade de RPE construída para a banda-X (~ 9,2 GHz), os \"softwares\" modificados e desenvolvidos para aquisição de dados, tratamento e reconstrução de imagens. São apresentados os resultados do aumento do sinal de RMN e as imagens obtidas através da Tomografia de Ressonância Magnética, usando amostras menores do que 1 mm de diâmetro (volume ~10 ul), a uma concentração de 2,2 mM de TEMPOL dissolvido em água destilada.This work describes in details the arrangements that must be accomplished for development of a spectrometer for Dynamic Nuclear Polarization - DNP (Overhauser Effect). Also, the construction project of a 14 MHz pulsed NMR spectrometer and drawings of a homemade EPR cavity for X-band (~ 9,2 GHz) are shown. The DNP probe built for the experiments and modifications done on the EPR spectrometer existing at Laboratory of Magnetic Resonance are discussed in detail. Results on the enhancement of the NMR signal due electron-proton dynamic interactions are presented. NMR imaging of very small objects, 1 mm diameter glass tube filled with 5 ~10 ul of 2,2 mM of free radicals (TEMPOL) solution, obtained through back projection reconstruction NMR tomography method, are presented
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Sá, Alessandro Aguiar de Castro. "Desenvolvimento de instrumentação para o estudo de materiais magnéticos usando RMN com campo externo zero". Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-20112013-210032/.
Testo completoAbstract (sommario):
Este trabalho de mestrado teve por objetivo a recuperação de um espectrômetro de RMN de dupla-ressonância construído na década de 1980 para o estudo de materiais no estado sólido. Esse espectrômetro foi parcialmente destruído por um raio que atingiu o prédio do IFSC-USP em 2001, tendo sua parte digital inutilizada, a qual envolvia o gerador de pulsos, e o digitalizador e promediador de sinais. Este trabalho envolveu a instalação de uma placa geradora de pulsos e um osciloscópio digital, ambos comerciais, controlados por um computador executando programas elaborados por nosso grupo. Embora o espectrômetro permita a implementação de técnicas de RMN de alta resolução de dupla-ressonância para o estudo de materiais no estado sólido, os primeiros experimentos de RMN foram realizados com materiais magnéticos, os quais permitiram sua execução sem a utilização do magneto supercondutor. No momento, esse espectrômetro encontra-se em fase de aprimoramento e testes de desempenho e já tornou possível a obtenção de resultados importantes em materiais magnéticosThe objective of this work was to repair and upgrade a double-resonance NMR spectrometer assembled in the 80s for studying solid-state materials. In 2001 this instrument was damaged by an atmospheric discharge that destroyed its digital modules, i.e., the pulse generator, digitizer, and averager. The work reported on here involved installing a new pulse-generator board and a programmable digital oscilloscope, both commercially available. These are computer-controlled by software developed by our research group. Although the spectrometer allows the use of double resonance NMR techniques for studying solid-state materials, the first experiments were done with magnetic materials, which required no superconducting magnet. Presently, the spectrometer is still being tested and improved. Even so, it is already capable of yielding important data in the study of magnetic materials
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França, Danilo Costa de. "Provas de cargas estáticas instrumentadas em profundidade em estacas escavadas de grande diâmetro (Estações)". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-08052012-120328/.
Testo completoAbstract (sommario):
Objetivou-se estudar o comportamento de estacas escavadas de grande diâmetro em uma obra de um Shopping Center na cidade de São Paulo. As estacas foram submetidas a carregamentos axiais de compressão, sendo que as estacas foram instrumentadas em profundidade. Utilizou-se de teorias amplamente conhecidas no meio técnico com o propósito de interpretar as curvas carga vs recalque, obtendo-se resultados como os diagramas de transferência de carga ao longo do fuste e atrito lateral unitário, gráficos do produto ES das estacas ensaiadas, gráficos de rigidez das estacas e as duas relações modificadas de Cambefort. O presente trabalho visa conseguir parâmetros que pudessem proporcionar uma redução no comprimento das estacas em obra e apresentar resultados que auxiliem os projetistas no dimensionamento de fundações usando-se estacas escavadas de grande diâmetro, sempre tendo cuidado e critério na extrapolação dos resultados em solos diferentes dos apresentados aqui.The objective of this Msc Thesis is to study the behavior of large diameter drilled pile in the construction of a shopping mall in Sao Paulo. The piles were subjected to axial compression loads and instrumented in depth. Widely known theories were used to interpret load vs settlement curves, obtaining such results as transfer loads diagrams along the shaft and lateral friction unit, ES product and stiffness grafics of tested piles and two modified Cambefort Laws. This paper aims to achieve parameters that will allow a reduction in pile lengths and to present results that will aid designers in the design of large diameter drilled pile, provided that the needed care is taken when extrapolating results to soils of different geological origins from those presented here.
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Dang, Phuc Hung. "Développement d’aimant bas champ pour RMN Portable : Conception et construction". Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0007/document.
Testo completoAbstract (sommario):
Les travaux menés au cours de cette thèse porté sur le développement d’un aimant pour système de RMN portable. Une homogénéité élevée a été recherchée tout en maintenant le champ magnétique statique B0 aussi élevé que possible (100ppm, 0.12T). Les dimensions de l’aimant sont prédéfinies ainsi que celles de la zone d'intérêt fonction de la taille des aimants permanents utilisés. Ce type de système est dédié à la recherche biomédicale et agroalimentaire. Les travaux présentés ont consisté, à discuter dans un premier temps un certain nombre des paramètres des matériaux magnétiques essentiels à la construction d’aimants de RMN portables. Plus particulièrement le choix des aimants permanents, utilisant un matériau tels que le NdFeB a été justifié. Une combinaison entre portabilité, prix et sensibilité a abouti à la conception d’un prototype d’aimant portable pour appareil RMN à partir d’un système simple d’arrangement de 24 aimants permanents. Le champ magnétique et l'homogénéité de ce système ont été calculés et simulés à l’aide du logiciel Ansys puis les résultats obtenus ont été vérifiés avec le logiciel Radia. Une nouvelle méthode de shim pour augmenter l'homogénéité et corriger les imperfections du champ B0 a été aussi introduite. La position des aimants de shim a fait l’objet d’une optimisation avec le logiciel Radia. Sur la base de ces résultats, un prototype a été réalisé. Les résultats des mesures de champ magnétique et de l'homogénéité sont en bonne corrélation avec les résultats obtenus par simulation. Les erreurs de mesure ont été estimées et une précision suffisante a été atteinte compte tenu des tolérances portant à la fois sur les caractéristiques et sur la fabrication des aimants. Un autre aimant basé sur la configuration Mandhalas (Magnet Arrangement for Novel Discrete Halbach Layout) a fait l’objet d’une étude comparative, portant sur deux configurations utilisant des aimants de formes circulaires et de formes carrés, a été effectuée par simulation 2D (sur la base de trois critères : la masse, l'homogénéité et l'intensité du champ magnétique). Les Mandhalas fabriqués à partir d’aimants circulaires permettent d’avoir de meilleurs résultats (0.32T, 178ppm). D’autre part, la simulation 3D a été faite afin d’évaluer la totalité du système. A partir des résultats obtenus, un système de shim passif a été aussi utilisé dans ce cas et a permis l’augmentation de la zone d'homogénéité de manière significativeThis thesis focuses on the development of a magnet system for NMR applications with high homogeneity while maintaining the static magnetic field B0 as high as possible (100 ppm, 0.12T). Due to the application goals, the magnet dimensions are predefined as well as those of the region of interest according to the size of the used permanent magnets. Such system is dedicated to biomedical and agroalimentary applications. The goal of this research has been firstly, the discussion of parameters of magnetic materials which are essential to the construction of portable NMR magnets, and then the choice of the permanent magnet material the “NdFeB” that was explained. A compromise between the portability, price and the sensitivity has led to the design of a prototype of portable NMR magnet with a simple system of arrangement of 24 permanent magnets. The magnetic field and the homogeneity of the system were calculated and simulated by using ANSYS software and these results were correlated to those obtained by the Radia software. A new shim method has been used to increase the homogeneity and correct the field B0 imperfection. Based on these results, a prototype was realized. The results of the magnetic field strength and homogeneity obtained by measurements are in good correlation with the results obtained by simulation. Sufficient accuracy was reached to take into account and correct errors due to manufacturing tolerances of the magnets. Another magnet system based on Mandhalas configuration (Magnet Arrangement for Novel Discrete Halbach Layout) was studied. The comparison between two configurations made from circle and square magnets was performed by 2D simulation (using three criteria: mass, homogeneity and the magnetic field strength). The Mandhalas made from circle magnets give better results (0.32 T, 178 ppm). The 3D simulation was carried out to evaluate the total system. From these results, a passive shim system was also used in this case and the homogeneity significantly increases
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Mallikarjunaiah, K. J. "NMR Instrumentation and Studies in Ammonium and methyl substituted Ammonium Compounds". Thesis, 2007. http://hdl.handle.net/2009/6392.
Testo completo
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"Application of electrolevels in geotechnical instrumentation". Tese, MAXWELL, 1999. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=1254:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.
Testo completo
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Hövener, Jan-Bernd [Verfasser]. "13C spin hyperpolarization by PASADENA : instrumentation, preparation of magnetic tracers, and NMR spectroscopy and imaging in vivo / put forward by Jan-Bernd Hövener". 2008. http://d-nb.info/992018307/34.
Testo completo
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Swarts, Gabriël Gerhardus. "Evaluation of selected digital instrumentation & control architectures for nuclear power plants to determine compliance with the NNR position paper PP-0017 requirements / Gabriël Gerhardus Swarts". Thesis, 2015. http://hdl.handle.net/10394/15598.
Testo completoAbstract (sommario):
The Instrumentation and Control (I&C) system is the central nervous-system of a nuclear power plant. New nuclear power plants being proposed to be built in this country all involve digital I&C systems, both safety related and non-safety related. The I&C systems of earlier Generation nuclear power plants are facing challenges with aging and obsolete analogue components. Technology has evolved in recent times and digital systems have replaced most analogue systems in other industries. Due to the safety and licencing requirements in the nuclear industry, the analogue and digital systems work concurrent in the protection and trip systems. The additional functionality of a digital I&C system will open up new possibilities to support operations as well as maintenance activities in the nuclear power plant.
For the I&C architectures and systems being evaluated by this study, the I&C architectures are based on existing digital platforms that were developed for nuclear power plants currently under construction in other countries.
The objective of this research project is to explain the development process of an I&C architecture, develop drivers and tactics from the National Nuclear Regulator (NNR) position paper PP-0017, evaluate and verify selected digital I&C architectures. The final objective is to synthesise a proposed digital I&C architecture in compliance with the requirements imposed by the NNR position paper PP-0017.MIng (Nuclear Engineering), North-West University, Potchefstroom Campus, 2015
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"Monitoring of the corumbá-i dam instrumentation by neural networks and the box & jenkins' models". Tese, MAXWELL, 2003. http://www.maxwell.lambda.ele.puc-rio.br/cgi-bin/db2www/PRG_0991.D2W/SHOW?Cont=4244:pt&Mat=&Sys=&Nr=&Fun=&CdLinPrg=pt.
Testo completo