Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-06-22T11:26:33Z No. of bitstreams: 0 / Made available in DSpace on 2016-06-22T11:26:33Z (GMT). No. of bitstreams: 0 / Este trabalho apresenta uma nova metodologia, simples e de baixo custo, para quantificação direta de urânio em compostos do ciclo do combustível nuclear, baseada na espectroscopia no infravermelho com transformada de Fourier (FTIR), utilizando a técnica de pastilhamento em KBr. Diferentes matrizes foram utilizadas para o desenvolvimento e validação analítica: nitrato de uranilo complexado com TBP (UO2(NO3)2.2TBP) em fase orgânica e nitrato de uranilo (UO2(NO3)2) em fase aquosa. O método para matriz de urânio em fase orgânica (UO2(NO3)2.2TBP em hexano/incorporado em KBr) apresentou linearidade (r = 0,9980) dentro da faixa analítica de 0,20% 2,85% de urânio na pastilha de KBr, LD de 0,02% e LQ de 0,03%, exatidão com recuperações acima de 101,0%, robustez e precisão (DPR < 1,6%). O método para matriz de urânio em fase aquosa (UO2(NO3)2/incorporado em KBr) apresentou linearidade (r = 0,9900) dentro da faixa analítica de 0,14% 0,29% de urânio na pastilha de KBr, LD de 0,01% e LQ de 0,02%, exatidão com recuperações acima de 99,4%, robustez e precisão (DPR < 1,6 %). Amostras de processo do ciclo do combustível nuclear foram submetidas a avaliação intralaboratorial e os resultados foram comparados estatisticamente por outras técnicas: Espectrometria de Fluorescência de Raios-X (FRX) e gravimetria. Os testes estatísticos (t-Student e Fischer) indicaram que a técnica por FTIR e as de referência são equivalentes, demonstrando que a nova metodologia pode ser empregada com sucesso nas análises de rotina para o controle de qualidade dos compostos nucleares. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T09:20:05Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T09:20:05Z (GMT). No. of bitstreams: 0 / O amido é um polissacarídeo produzido pelos vegetais para reserva de energia e está disponível em abundância na natureza. Os amidos são preparados a partir de diferentes matérias primas, tais como trigo, cevada, milho, arroz, batata, batata doce ou mandioca. Na dieta humana o amido é utilizado como fonte de energia biológica. Na indústria de alimentos, o amido é utilizado para alterar ou controlar diversas características, como textura, aparência, umidade, consistência e estabilidade. Entretanto, há uma contínua procura por novas tecnologias para o desenvolvimento de novas propriedades funcionais para melhor adequação às necessidades do mercado. A radiação ionizante pode ser aplicada na modificação de macromoléculas como a do amido. O presente trabalho teve como objetivo estudar as características de amidos de batata, milho e mandioca (polvilho azedo) tratados com radiação ionizante e os correspondentes filmes comestíveis preparados com eles. Os amidos em pó foram submetidos à radiação em fonte de 60Co Gammacell 220 com doses de 0, 1, 5, 10 e 15 kGy, taxa de dose em torno de 1 kGy h-1. Para o estudo dos amidos foram empregadas técnicas de microscopia, análises térmicas, espectroscopia no infravermelho, difração de raios-X e viscosimetria. Para os filmes foram avaliadas propriedades mecânicas, análise instrumental da cor, capacidade de absorção e índice de solubilidade. Constatou-se que a radiação não influenciou a morfologia dos grânulos, a termogravimetria e o padrão de difração de raios-X. A viscosidade dos hidrogéis dos amidos diminuiu com o aumento da dose de radiação e estes apresentaram características de fluidos não-Newtonianos e pseudoplásticos. Na avaliação instrumental da cor dos filmes houve um ligeiro aumento no parâmetro b*(cor amarela). A força de ruptura dos filmes decresceu conforme aumento da dose de radiação aplicada dependendo do tipo de amido empregado na sua fabricação. A capacidade de absorção em água diminuiu e a solubilidade aumentou com a radiação. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Thesis (MSc (Physics))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Highly exotic nuclei can be studied in rare reactions using stable beams, with macroscopic intensities, and thick targets. Exotic nuclei are interesting for a number of reasons e.g. for testing nuclear models under conditions of high isospins. In the case of very neutron-deficient nuclei, two-proton decay is the most recently discovered nuclear decay mode and the subject of many theoretical investigations involving cluster and shell models. This thesis presents a feasibility study of investigating light exotic nuclei near the proton drip line with the K600 magnetic spectrometer. The 27Al(3He,8He)22Al five-neutron pick-up reaction was investigated at a spectrometer angle of θlab = 8◦ with a beam energy of Elab = 220 MeV. This reaction can be used to populate highly neutron-deficient nuclei. Should the study of this reaction prove to be feasible, then a number of nuclei on the proton drip line or beyond could be investigated. A new data acquisition system, with VME electronics and MIDAS software, was used along with one new drift chamber, which consists of both an X wire plane and a U wire plane. The particles 1,2,3H and 3,4He were all identified as outgoing particles from the collision of 3He with 27Al. Cross section calculations were performed for these observed reactions. Discrete spectra for the (3He,6He) and (3He,8He) reactions could not be identified. The mass calculation of A ∼ 20 nuclei on the proton drip line depends on the determination of the Coulomb energy, which differs a lot between mirror nuclei. Mass calculations were performed for known nuclei in the mass region A ≤ 50, using the Isobaric Multiplet Mass Equation. Agreement with experimental data was found to be far better in odd nuclei than in even nuclei. Hence mass predictions were performed for odd nuclei along the proton drip line. / AFRIKAANSE OPSOMMING: Hoogs eksotiese kerne kan bestudeer word in seldsame reaksies deur middel van stabiele bundels, met makroskopiese intensiteite, en dik teikens. Eksotiese kerne is interessant om verskeie redes, onder andere om kernfisiese modelle te toets onder omstandighede van ho¨e isospin. In die geval van baie neutron-arm kerne is twee-proton verval die nuutste ontdekte tipe van kernverval. Dit is ook die onderwerp van vele teoretiese studies met betrekking tot bondel en skilmodelle. Hierdie tesis beskryf ‘n uitvoerbaarheidstudie vir die ondersoek van ligte eksotiese kerne naby die proton drup lyn met behulp van die K600 magnetiese spektrometer. Die 27Al(3He,8He)22Al vyf-neutron kaapreaksie is ondersoek by ‘n spektrometer hoek van θlab = 8◦ met ‘n bundel energie van Elab = 220 MeV. Sou die uitvoerbaarheidstudie van hierdie reaksie slaag, dan kan verskeie kerne op of anderkant die proton drup lyn ondersoek word. ‘n Nuwe data verkrygingssisteem, met VME elektronika en MIDAS sagteware, is gebruik saam met een nuwe dryfkamer, wat bestaan uit beide ‘n X draadvlak en ‘n U draadvlak. Die partikels 1,2,3H en 3,4He is almal geidentifiseer as uitgaande partikels van die botsing van 3He met 27Al. Kansvlak-berekeninge is uitgevoer vir alle waargenome reaksies. Diskrete spektra kon nie gevind word vir die (3He,6He) of (3He,8He) reaksies nie. Die massa berekening van A ∼ 20 kerne op die proton drup lyn is afhanklik van die bepaling van die Coulomb energie, wat baie verskil tussen spie¨elkerne. Massa berekeninge is uitgevoer vir bekende kerne in die massa gebied A ≤ 50, deur die gebruik van die Isobariese Multiplet Massa Vergelyking. Die ooreenstemming met eksperimentele data was baie beter in die geval van onewe kerne as met ewe kerne. Daarom was die massa voorspellings uitgevoer vir slegs onewe kerne naby die proton drup lyn.

No description available.

No description available.

No description available.

No description available.

No description available.

Optical detection devices such as optical biosensors and optical spectrometers are widely used in many applications for the functions of measurements, inspections and analysis. Due to the large dimension of prisms and gratings, the traditional optical devices normally occupy a large space with complicated components. Since cheaper and smaller optical devices are always in demand, miniaturization has been kept going for years. Thanks to recent fabrication advances, nanophotonic devices such as semiconductor laser chips have been growing in number and diversity. However, the optical biosensor chips and the optical spectrometer chips are seldom reported in the literature. For the reason of improving system integration, the study of ultra-compact, low-cost, high-performance and easy-alignment optical biosensors and optical spectrometers are imperative. This thesis is an endeavor in these two subjects and will present our research work on studying the optical transmission properties of dielectric aperture arrays and developing new optical biosensors and optical spectrometers. / Subsequently, optical transmission properties through a self-mixing interferometer array are studied and a novel high-resolution cost-effective optical spectrometer is proposed. The miniature interferometer-based spectrometer is made of polymethyl methacrylate (PMMA) with a CCD as the detector. The detected intensity of each CCD pixels contains the spectral information. Since each frequency component in the incoming beam corresponds to a unique phase difference of the two beam portions of each optical interferometer, the total intensity received by each CCD pixel, which is resulted from the addition of the interference signals from all the frequency components in the beam, should also be unique. Therefore, the spectrum calculation is a problem to solve an ill-posed linear system by using Tikhonov regularization method. Simulation results show that the resolution can reach picometer level. Apart from the choice of path difference between the interfering beams, the spectral resolution also depends on the signal-to-noise ratio and analogue-digital conversion resolution (dynamic range) of the CCD chip. In addition, the theory of uniform waveguide scattering is explored to expand the possibility of using such mini-interferometers for performing free-space spectral analysis of waveguide devices. At the same time, the method of least squares is used to correct the pixel non-uniformity of the CCD so as to improve the performance of the spectrometer. / The first half of the thesis demonstrates that the optical phase shift associated with the surface plasmon (SP) assisted extraordinary optical transmission (EOT) in nano-hole arrays fabricated in a metal film has a strong dependence on the material refractive index value in close proximity to the holes. A novel refractive index sensor based on detecting the EOT phase shift is proposed by building a model. This device readily provides a 2-D biosensor array platform for non-labeled real-time detection of a variety of organic and biological molecules in a sensor chip format, which leads to a high packing density, minimal analyte volumes, and a large number of parallel channels while facilitating high resolution imaging and supporting a large space-bandwidth product (SBP). Simulation (FDTD Solutions, Lumerical Solutions Inc) results indicate an achievable sensitivity limit of 4.37x10-9 refractive index units (RIU) and a dynamic range as large as 0.17 RIU. / The sensor chip and spectrometer chip introduced here are based on the interference of light transmitted through dielectric aperture arrays. Their compact feature renders these devices ideal for miniaturization and integration as the systems in microfluidics architectures and lab-on-chip designs. / Yang, Tao. / Adviser: H. P. Ho. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 150-163). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The RF high power amplifier is a key module in the NMR spectrometer. Robustness, lower power consumption, and small size are requirements. In this thesis, devices are studied and different design approaches are considered. New ideas are introduced, and simulations are used to show if it these work. A real prototype is developed. Results from the prototype are satisfactory and in good agreement with the simulation results. This allows for the possibility of a real portable NMR spectrometer 'Lapspec'. Points of note: • Feedback to stabilize amplifier, • Hard bias to improve rise time of pulse, • A rugged device is chosen, • Power limiter technology is used to avoid overdrive amplifier, • Lower value attenuator at output of final stage to reduce load VSWR, • Reason of spike is studied, the solution to reduce spike is given, • The reason of instability of amplifier with NMR load is analyzed, • A method is introduced to ensure there is no oscillation while the High Power Amplifier (HPA) is connected with the NMR probe.