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Tsunami Vulnerability Assessment of the Canadian Pacific CoastCheff, Isabelle January 2016 (has links)
The North American Pacific coast, located within the Ring of Fire, is at risk of severe subduction tsunamis. This danger has pushed the United States to make a strong push in tsunami research. Recent advancement has resulted in the implementation of a new chapter in the ASCE 7-16 standards focusing on tsunami structural loads and effects. Within the scope of this new standard, the tsunami inundation hazard of the US West coast has been mapped. However, no such work has been completed in Canada, leaving the tsunami hazard and vulnerability for most of the Canadian West coast uncertain.
The life safety vulnerability from the most hazardous source, the Cascadia Subduction Zone, is evaluated in terms of pedestrian evacuation capabilities. Using a static distance-only model, the ability of individuals to evacuate to safety in natural high grounds is computed for all communities in British Columbia and compared by Tsunami Notification Zone. A new variable – the available time – for tsunamis life safety vulnerability assessment is proposed. This variable considers both tsunami arrival time and time to safety, resulting in a life safety threshold value of 0. Zone E has the largest surface area and population within the hazard zone, even though it has the smallest probable run-up range because of the large number of communities in this zone and the low-laying areas of the Lower Mainland. All communities within Zones A, B, D, and E have low life safety vulnerability at the maximum probable run-up of their respective zone, suggesting that pedestrian evacuation should be possible. Zone C has the highest vulnerability of all zones, as it has the lowest available times. With a 9 m run-up and over 25% of its communities lying within the moderate- or high-vulnerability categories, it has an available time of below 30 min and 15 min, respectively. Zone C also has the highest percentage of its surface area inundated at its maximum probable run-up (39.7%). The most vulnerable communities are identified, including 45 First Nation and 5 non-indigenous communities: Tofino, Winter Harbour, Ucluelet, Port Renfrew, and Bamfield. The life-safety threshold is surpassed in Barlett Island 32, Grassy Island 17, Hesquiat 1, and Tofino. Delta and Richmond, in Zone E, also have a minimum available time below the life safety threshold at run-ups between 5 and 7 m, at or above the probable run-up of their zone, as they have large low-lying areas. As the tsunami arrival time is very large here, the merits of vehicle evacuation should be evaluated. Additionally, they are likely to be more vulnerable to landslide tsunamis, as the tsunami arrival time would be much shorter than one from a Cascadia tsunami.
A more detailed vulnerability study using anisotropic path-distance modeling was performed in Tofino. This more complex model found lower available times than the distance-only model. Maximum differences ranging between 14.4 to 29.9 minutes were found for three pedestrian velocities. The minimum available time was found to be -29.0 minutes within the official municipality boundary and -40.1 minutes within one of the beaches. Two vertical evacuation structures are required to reduce the time to safety below the tsunami arrival time of 28.1 minutes for run-ups between 13 and 19 m. Run-ups above 19 m required three vertical evacuation structures. No configuration could be found to sufficiently reduce the time to safety on Frank Island.
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A Multi-Compartment Model of the Normal Menstrual Cycle: Integrating Hormonal, Ovarian, and Endometrial ElementsWolf, Victoria Lea 17 May 2014 (has links)
The uterine endometrium undergoes cyclical phases of cell proliferation, cell differentiation, and menstruation under the influence of the ovarian hormones, estrogen and progesterone. Since the data necessary to create a classical kinetic model of these signaling pathways is lacking, we used a Boolean network approach that includes the influences of various growth factors and the differential expression of their receptors under the influence of estrogen and progesterone. Results show a gain in endometrial tissue and loss of tissue during menstruation that mirrors what can be expected over the course of a normal menstrual cycle in women, where the endometrium typically reaches a thickness of approximately 10 mm. We utilized an existing model of the normal menstrual cycle that was used to predict hormonal changes following administration of GnRH analogues. We adapted this model to provide the hormonal and ovarian compartments that would interact with our model of the endometrial cycle.
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キイロショウジョウバエ(Drosophila melanogaster)におけるBH3-only protein、sayonaraの発見池川, 優子 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(生命科学) / 甲第24755号 / 生博第496号 / 新制||生||66(附属図書館) / 京都大学大学院生命科学研究科高次生命科学専攻 / (主査)教授 北島 智也, 教授 井垣 達吏, 教授 鈴木 淳 / 学位規則第4条第1項該当 / Doctor of Philosophy in Life Sciences / Kyoto University / DFAM
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Limitations of Initial Orbit Determination Methods for Low Earth Orbit CubeSats with Short Arc Orbital PassesJohnson, James P 01 July 2020 (has links) (PDF)
This thesis will focus on the performance of angles only initial orbit determi- nation (IOD) methods on observational data of low Earth orbit (LEO) CubeSats. Using data obtained by Lockheed Martin’s Space Object Tracking (SpOT) facil- ity, four methods: Gauss, Double-R, Gooding and Assumed Circular, will use different amounts of orbital arc to determine which methods perform the best in the short arc regime of less than 10 degrees of orbital arc. Once the best method for estimating the orbit is determined, there will be analysis on whether these IOD methods are accurate enough to predict a secondary observation session. Finally non-linear regression will be performed to determine if the error metrics follow a predictable trend based on how much orbital arc is seen by the observer. It was determined that above a certain amount of orbital arc, angles only IOD methods can reliably predict a secondary observation session to facilitate more observations. Below 4 degrees of orbital arc, which is around 60 seconds of ob- serving time for LEO objects, none of the methods were able to reliably predict a secondary observation session. The Assumed Circular method was the best method for observing LEO CubeSats because it forces the IOD solution to be circular, which limits the error in the shape of the orbit as the amount of orbital arc decreases. Finally, many metrics follow an exponential trend when compared to the orbital arc. Thus, the amount of orbital arc seen is a strong predictor for the accuracy of the angles only IOD solutions.
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A Series of Improved and Novel Methods in Computer Vision EstimationAdams, James J 07 December 2023 (has links) (PDF)
In this thesis, findings in three areas of computer vision estimation are presented. First, an improvement to the Kanade-Lucas-Tomasi (KLT) feature tracking algorithm is presented in which gyroscope data is incorporated to compensate for camera rotation. This improved algorithm is then compared with the original algorithm and shown to be more effective at tracking features in the presence of large rotational motion. Next, a deep neural network approach to depth estimation is presented. Equations are derived relating camera and feature motion to depth. The information necessary for depth estimation is given as inputs to a deep neural network, which is trained to predict depth across an entire scene. This deep neural network approach is shown to be effective at predicting the general structure of a scene. Finally, a method of passively estimating the position and velocity of constant velocity targets using only bearing and time-to-collision measurements is presented. This method is paired with a path planner to avoid tracked targets. Results are given to show the effectiveness of the method at avoiding collision while maneuvering as little as possible.
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The effect of parental brokering on adult sociability : a comparison of only and nononly children /Johnson, Barbara E. January 1985 (has links)
No description available.
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Investigations of Horizontal-Parallax-Only Optical Scanning Holography (HPO-OSH) through MATLAB SimulationsAkin, Enver Turan 23 June 2006 (has links)
The concept of generating horizontal-parallax-only (HPO) holograms by computer simulations is investigated. The simulations in this thesis are based on Optical Scanning Holography (OSH) aimed at acquiring HPO information electronically. The principles of OSH, a technique that allows the extraction of 3-D information by a 2-D optical scan of the object is first summarized. The HPO principles and simulation scenarios are then discussed. In order to illustrate the ideas, holograms were created and reconstructed using MATLAB simulations. The holograms are simulated by convolving the Fresnel zone plates (FZP) with the object. The simulations focus on generating HPO holograms using 1-D FZPs modeled as 1-D Gaussian chirp beams of varying waists. An optical reconstruction scheme by cylindrical lens was proposed and simulated. Three-dimensional imaging using HPO-holograms was also discussed. Several reconstruction scenarios were investigated by digitally convolving the complex HPO-hologram with the free space impulse response or the Gaussian chirp beam. Although many ideas of HPO-holography have been proposed and studied, to the best of our knowledge, this is the first proposed electronic technique to acquire HPO-holographic information. The simulations demonstrate that holographic information reduction techniques also help to alleviate the problems associated with the restricted field of view upon holographic reconstruction for 3-D display. The simulations show that horizontal-parallax-only holography is an excellent way to reduce holographic information. Suggested future work includes actual optical experimentation to verify the ideas presented in this thesis. / Master of Science
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Novas metodologias de ressonância magnética nuclear para o estudo da dinâmica lenta em materiais orgânicos no estado sólido: aplicações em polímeros e proteínas / New nuclear magnetic resonance methods for studying slow dynamics in organic solids: applications to polymers and proteinsAzevêdo, Eduardo Ribeiro de 30 November 2001 (has links)
RMN de Exchange em estado sólido é uma importante técnica utilizada na caracterização de processos dinâmicos em ciência dos materiais. Entretanto, a utilização desta técnica no estudo de materiais complexos tem sido limitada. Neste trabalho, serão propostas novas metodologias de RMN de Exchange em estado sólido, que permitem analisar eficientemente movimentos moleculares na escala de tempo de milisegundos. A técnica denominada Pure Exchange Solid-State NMR (PUREX), provê a supressão dos segmentos rígidos dos espectros de exchange, tomando possível observar os segmentos com mobilidade na escala de ms seletivamente. A técnica Centerband-Only Detection of Exchange (CODEX), permite a observação e caracterização de reorientações moleculares lentas com a maior sensibilidade e resolução disponíveis em RMN de estado sólido, através de espectros obtidos sob rotação da amostra em tomo do ângulo mágico (MAS). Utilizando essas técnicas as funções e tempos de correlação e a geometria de movimentos moleculares lentos podem ser determinadas diretamente, sem a necessidade da utilização de modelos que relacionem as grandezas medidas e as características do movimento molecular. A utilização dos métodos apresentados, permite a identificação e caracterização da dinâmica lenta em materiais complexos, tais como polímeros amorfos, semicristalinos e proteínas. Com objetivo inicial de demonstrar as técnicas, elas foram aplicadas para confirmar detalhes da dinâmica molecular em amostras modelo. Através destas técnicas foi possível confirmar a escala de tempo e os ângulos de reorientação envolvidos na dinâmica molecular de cristais orgânicos, Dimetil Sulfona (DMS), e também para revisitar processos de relaxação local em alguns polímeros, polimetacritato de metila (PMMA) e isotatico polipropileno (iPP). As metodologias foram também aplicadas no estudo da transição vítrea em polímeros semicristalinos, isotatico poli(1-buteno) (iPB 1) e sindiotático polipropileno, os quais não tinham sido ainda estudados por técnicas de RMN de Exchange, já que neste caso a maioria dos segmentos moleculares (porção cristalina do polímero) é rígida durante a transição vítrea. Utilizando os métodos CODEX e PUREX os movimentos lentos que ocorrem na região amorfa destes polímeros em temperaturas próximas as suas temperaturas de transição vítrea foram caracterizados. Um estudo dos movimentos lentos que ocorrem em tomo das temperaturas de transição vítrea nas cadeias poliméricas de dois tipos de nanocompostos híbridos siloxano/(polietileno glicol) (ormolitas) também é apresentado. Heterogeneidades nos movimentos das cadeias poliméricas associados com a interação PEG/siloxano foram diretamente observadas através de experimentos PUREX 1D de Exchange 2D. Evidenciais da presença de movimentos de grande e pequena amplitude foram observados para os dois tipos de híbridos. Os resultados revelam que a restrição do movimento das cadeias poliméricas pelas estruturas de siloxano depende tanto do comprimento da cadeia como da natureza das interações entre as fases orgânica e inorgânica do nanocomposto. Finalmente os resultados referentes a caracterização da dinâmica molecular rápida e lenta e sua relação com as propriedades estruturais de um hidrogel protéico são apresentados. Utilizando uma versão modificada da técnica CODEX, juntamente com experimentos de polarização direta, polarização cruzada e RMN de correlação 2D, foi possível não somente confirmar a estrutura e o modelo de formação propostos para o gel, mas também determinar a geometria e a escala de tempo dos movimentos lentos que ocorrem na região de hélice do hidrogel protéico em grandes detalhes. A demonstração teórica e experimental das técnicas e suas aplicações no estudo dessas importantes classes de materiais serão apresentadas. / Solid-State Exchange NMR is an important method to characterize details of dynamic process in materials science. However, the application of these techniques to study complex materials has been limited. In this work new solid-state Exchange NMR techniques, which allows efficient analysis of molecular motions in the millisecond time scale, are presented. The Pure Exchange Solid-State NMR (PUREX) method provides the suppression of the rigid segments in standard exchange spectrum, making possible to observe the slow moving moieties selectively. The Centerband-Only Detection of Exchange (CODEX) technique allows observing and characterizing slow segmental reorientations with the highest available NMR sensitivity and site resolution, in a magic angle spinning (MAS) NMR spectrum. Correlation functions, correlation times and information about the motional amplitude and geometry can be direct1y obtained using the techniques, without any model assumption. These methods allowed identifying and characterizing slow dynamics in complex materials such as, semicrystalline and amorphous polymers and proteins. To demonstrated the proposed techniques they have been applied to confirm some kwon aspect of the slow dynamics of model samples. Using the methods it was possible o confirm the time scale and the reorientation angles involved in the molecular dynamics of organic crystals, Dimethyl Sulfone (DMS), and also to revisit some relaxation process in standard polymers, such as the beta relaxation of poly(methyl metacrylate) (PMMA) and the alfa relaxation in isotactic polypropylene (iPP). The time scale and the geometry of the molecular motions responsible by these relaxation process obtained using the PUREX and CODEX techniques are in excellent agreement with the data taken from the literature, confirming the reliability of the proposed methods. Moreover, the techniques were also applied to study the slow molecular motions involved in the glass transition of semicrystalline polymers, such as isotactic poly (l-butene) form I (iPB1) and syndiotactic Polypropylene (sPP). The glass transition of these polymers had not been studied using Exchange NMR methods because most of the molecular segments (crystalline portion of the polymers) are rigid during the glass transition. Using the PUREX and CODEX methods the slow molecular reorientations within the amorphous region of the polymers were characterized for temperatures near its glass transition. A study of the slow motions occurring around the glass transition temperature in the polymer chains of two types of siloxane/(polyethylene glycol) nanocomposites (ormolites) is also presented. Motional heterogeneities associated with PEG/ siloxane interactions were directly observed in the 13C 1D PUREX and 2D exchange data. Evidences of both small and large angle amplitude motions were direct1y observed for both types of hybrids. The results revealed that the hindrance to the slow molecular motions of the polymer chains due to the siloxane structures depends on the chain length and the nature of the interaction between the organic and inorganic phases. Finally the results concerning the characterization of the fast and slow dynamics and its relationship with the structural properties of a protein hidrogel are presented. Using a modified version of the CODEX technique, together with standard direct polarization, cross polarization and 2D NMR correlation experiments, it was possible not only to confirm the proposed structure and the gel formation model, but also to characterize the geometry and the time scale of the slow motions in the helical domains of the protein hidrogel in great detail. The theoretical and experimental demonstration of all proposed methods and also its applications in these important classes of material will be present.
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Arroz tolerante a imidazolinonas: controle do arroz vermelho, persistência de herbicidas e fluxo gênico / Imidazolinone tolerant rice: red rice control, herbicide persistence and outcrossingVilla, Silvio Carlos Cazarotto 30 March 2006 (has links)
Red rice (Oryza spp.) is one of the main limiting factors to rice (O. sativa L.) yield. After several decades searching for red rice control tools, it was developed imidazolinone tolerant rice, to selectively control red rice. To better understand this technology it were conducted two experiments in 2004/05, in Santa Maria, Rio Grande do Sul state, Brazil. The first experiment (Chapter I) had the objective of: 1) evaluate red rice control by imidazolinone herbicides in Clearfield rice; 2) evaluate the imidazolinone herbicide carryover effect on rygrass and non-tolerant rice (IRGA 417) and 3) evaluate the outcrossing rates between Clearfield rice and red rice. The
herbicides tested control red rice. Although injury to Clearfield rice was observed, the herbicide did not affected yield. It was observed herbicide carryover to non-tolerant rice, reducing plant stand. There was natural outcrossing between Clearfield rice and red rice, at rates of 0.065%. The second experiment (Chapter II) had the objective of evaluate the herbicide Only® (imazethapyr 75 g L-1 + imazapic 25 g L-1) in different application rates and timing on two genotypes, IRGA 422 CL and Tuno CL, to the imidazolinones herbicides. When compared with the cultivar, the hybrid was more tolerant to the herbicide Only®. It was possible to apply rates of up to 2.0 L ha-1 in the hybrid, without affecting rice yield. Red rice control was total with split application of Only® in PRE and POST, with rates above 1.25 L ha-1. The most efficient treatment was with application of 0.75 L ha-1 in PRE followed by 0.5 L ha-1 in POS, because, it was the lowest rate that promoted 100% control, with relatively low toxicity to the cultivar and without affecting rice yield. / O arroz-vermelho (Oryza spp.) é um dos principais fatores limitantes da produtividade de grãos do arroz irrigado (O. sativa L.). Após várias décadas de busca de alternativas para o controle seletivo do arroz-vermelho, desenvolveram-se
genótipos de arroz tolerante a herbicida do grupo químico das imidazolinonas, o qual controla eficiente e seletivamente esta planta daninha. Para estudar e melhor entender esta tecnologia, conduziu-se dois experimentos em Santa Maria-RS no ano agrícola 2004/05. O primeiro experimento (Capítulo I) teve como objetivos: 1) avaliar a eficiência do controle de arroz-vermelho com o herbicida Only? (imazethapyr 75 g L-1 + imazapic 25 g L-1), 2) avaliar o residual do herbicida no solo através dos danos causados no azevém e em arroz não tolerante e 3) avaliar a taxa de ocorrência de cruzamento natural entre o arroz-vermelho e o arroz cultivado. O herbicida testado controla eficientemente o arroz-vermelho em arroz tolerante. Embora tenha-se observado fitotoxicidade, não houve redução na produtividade da cultivar tolerante. O estande inicial da cultivar IRGA 417 é afetado pelo residual do herbicida presente no solo. Ocorre cruzamento natural entre o arroz-vermelho e o arroz cultivado, sendo que a taxa de ocorrência obtida no experimento foi de 0,065%. O segundo experimento (Capítulo II) teve como objetivo avaliar o controle de arroz-vermelho e o
desempenho de dois genótipos de arroz irrigado, IRGA 422 CL e Tuno CL, tolerantes a herbicidas do grupo das imidazolinonas a doses e épocas de aplicações do herbicida Only? , em áreas com alta infestação de arroz-vermelho. Constata-se que o híbrido é mais tolerante ao herbicida Only? , quando comparado à cultivar IRGA 422 CL, sendo possível a utilização de dose total de até 2,0 L ha-1 no híbrido, em áreas com alta infestação de arroz-vermelho, sem afetar a produtividade. O controle de arroz-vermelho é total com aplicação fracionada do herbicida em pré e pós-emergência (PRE + POS), desde que o total aplicado não seja inferior a 1,25 L ha-1. Esta condição é atendida pelo tratamento com 0,75 L ha-1 em PRE mais 0,5 L ha-1 em POS, o qual propicia a menor dose total dentre aqueles com 100% de controle, não afetando a produtividade e com fitotoxicidade semelhante ao tratamento com 1,0 L ha-1 em POS, utilizado como referência.
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Novas metodologias de ressonância magnética nuclear para o estudo da dinâmica lenta em materiais orgânicos no estado sólido: aplicações em polímeros e proteínas / New nuclear magnetic resonance methods for studying slow dynamics in organic solids: applications to polymers and proteinsEduardo Ribeiro de Azevêdo 30 November 2001 (has links)
RMN de Exchange em estado sólido é uma importante técnica utilizada na caracterização de processos dinâmicos em ciência dos materiais. Entretanto, a utilização desta técnica no estudo de materiais complexos tem sido limitada. Neste trabalho, serão propostas novas metodologias de RMN de Exchange em estado sólido, que permitem analisar eficientemente movimentos moleculares na escala de tempo de milisegundos. A técnica denominada Pure Exchange Solid-State NMR (PUREX), provê a supressão dos segmentos rígidos dos espectros de exchange, tomando possível observar os segmentos com mobilidade na escala de ms seletivamente. A técnica Centerband-Only Detection of Exchange (CODEX), permite a observação e caracterização de reorientações moleculares lentas com a maior sensibilidade e resolução disponíveis em RMN de estado sólido, através de espectros obtidos sob rotação da amostra em tomo do ângulo mágico (MAS). Utilizando essas técnicas as funções e tempos de correlação e a geometria de movimentos moleculares lentos podem ser determinadas diretamente, sem a necessidade da utilização de modelos que relacionem as grandezas medidas e as características do movimento molecular. A utilização dos métodos apresentados, permite a identificação e caracterização da dinâmica lenta em materiais complexos, tais como polímeros amorfos, semicristalinos e proteínas. Com objetivo inicial de demonstrar as técnicas, elas foram aplicadas para confirmar detalhes da dinâmica molecular em amostras modelo. Através destas técnicas foi possível confirmar a escala de tempo e os ângulos de reorientação envolvidos na dinâmica molecular de cristais orgânicos, Dimetil Sulfona (DMS), e também para revisitar processos de relaxação local em alguns polímeros, polimetacritato de metila (PMMA) e isotatico polipropileno (iPP). As metodologias foram também aplicadas no estudo da transição vítrea em polímeros semicristalinos, isotatico poli(1-buteno) (iPB 1) e sindiotático polipropileno, os quais não tinham sido ainda estudados por técnicas de RMN de Exchange, já que neste caso a maioria dos segmentos moleculares (porção cristalina do polímero) é rígida durante a transição vítrea. Utilizando os métodos CODEX e PUREX os movimentos lentos que ocorrem na região amorfa destes polímeros em temperaturas próximas as suas temperaturas de transição vítrea foram caracterizados. Um estudo dos movimentos lentos que ocorrem em tomo das temperaturas de transição vítrea nas cadeias poliméricas de dois tipos de nanocompostos híbridos siloxano/(polietileno glicol) (ormolitas) também é apresentado. Heterogeneidades nos movimentos das cadeias poliméricas associados com a interação PEG/siloxano foram diretamente observadas através de experimentos PUREX 1D de Exchange 2D. Evidenciais da presença de movimentos de grande e pequena amplitude foram observados para os dois tipos de híbridos. Os resultados revelam que a restrição do movimento das cadeias poliméricas pelas estruturas de siloxano depende tanto do comprimento da cadeia como da natureza das interações entre as fases orgânica e inorgânica do nanocomposto. Finalmente os resultados referentes a caracterização da dinâmica molecular rápida e lenta e sua relação com as propriedades estruturais de um hidrogel protéico são apresentados. Utilizando uma versão modificada da técnica CODEX, juntamente com experimentos de polarização direta, polarização cruzada e RMN de correlação 2D, foi possível não somente confirmar a estrutura e o modelo de formação propostos para o gel, mas também determinar a geometria e a escala de tempo dos movimentos lentos que ocorrem na região de hélice do hidrogel protéico em grandes detalhes. A demonstração teórica e experimental das técnicas e suas aplicações no estudo dessas importantes classes de materiais serão apresentadas. / Solid-State Exchange NMR is an important method to characterize details of dynamic process in materials science. However, the application of these techniques to study complex materials has been limited. In this work new solid-state Exchange NMR techniques, which allows efficient analysis of molecular motions in the millisecond time scale, are presented. The Pure Exchange Solid-State NMR (PUREX) method provides the suppression of the rigid segments in standard exchange spectrum, making possible to observe the slow moving moieties selectively. The Centerband-Only Detection of Exchange (CODEX) technique allows observing and characterizing slow segmental reorientations with the highest available NMR sensitivity and site resolution, in a magic angle spinning (MAS) NMR spectrum. Correlation functions, correlation times and information about the motional amplitude and geometry can be direct1y obtained using the techniques, without any model assumption. These methods allowed identifying and characterizing slow dynamics in complex materials such as, semicrystalline and amorphous polymers and proteins. To demonstrated the proposed techniques they have been applied to confirm some kwon aspect of the slow dynamics of model samples. Using the methods it was possible o confirm the time scale and the reorientation angles involved in the molecular dynamics of organic crystals, Dimethyl Sulfone (DMS), and also to revisit some relaxation process in standard polymers, such as the beta relaxation of poly(methyl metacrylate) (PMMA) and the alfa relaxation in isotactic polypropylene (iPP). The time scale and the geometry of the molecular motions responsible by these relaxation process obtained using the PUREX and CODEX techniques are in excellent agreement with the data taken from the literature, confirming the reliability of the proposed methods. Moreover, the techniques were also applied to study the slow molecular motions involved in the glass transition of semicrystalline polymers, such as isotactic poly (l-butene) form I (iPB1) and syndiotactic Polypropylene (sPP). The glass transition of these polymers had not been studied using Exchange NMR methods because most of the molecular segments (crystalline portion of the polymers) are rigid during the glass transition. Using the PUREX and CODEX methods the slow molecular reorientations within the amorphous region of the polymers were characterized for temperatures near its glass transition. A study of the slow motions occurring around the glass transition temperature in the polymer chains of two types of siloxane/(polyethylene glycol) nanocomposites (ormolites) is also presented. Motional heterogeneities associated with PEG/ siloxane interactions were directly observed in the 13C 1D PUREX and 2D exchange data. Evidences of both small and large angle amplitude motions were direct1y observed for both types of hybrids. The results revealed that the hindrance to the slow molecular motions of the polymer chains due to the siloxane structures depends on the chain length and the nature of the interaction between the organic and inorganic phases. Finally the results concerning the characterization of the fast and slow dynamics and its relationship with the structural properties of a protein hidrogel are presented. Using a modified version of the CODEX technique, together with standard direct polarization, cross polarization and 2D NMR correlation experiments, it was possible not only to confirm the proposed structure and the gel formation model, but also to characterize the geometry and the time scale of the slow motions in the helical domains of the protein hidrogel in great detail. The theoretical and experimental demonstration of all proposed methods and also its applications in these important classes of material will be present.
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