The development and fabrication of silicon-based phononic band gap crystals has been gaining interest since phononic band gap crystals have implications in fundamental science and display the potential for application in engineering by providing a relatively new platform for the realization of sensors and signal processing elements. The seminal study of phononic band gap phenomenon for classical elastic wave localization in structures with periodicity in two- or three-physical dimensions occurred in the early 1990’s. Micro-integration of silicon devices that leverage this phenomenon followed from the mid-2000’s until the present. The reported micro-integration relies on exotic piezoelectric transduction, phononic band gap crystals that are etched into semi-infinite or finite-thickness slabs which support surface or slab waves, phononic band gap crystals of numerous lattice constants in dimension and phononic band gap crystal truncation by homogeneous mediums or piezoelectric transducers. The thesis reports, to the best of the author's knowledge, for the first time, the theory, design methodology and experiment of an electrostatically actuated silicon-plate phononic band gap quasi-crystal architecture, which may serve as a platform for the development of a new generation of silicon-integrated sensors, signal processing elements and improved mechanical systems. Electrostatic actuation mitigates the utilization of piezoelectric transducers and provides action at a distance type forces so that the phononic band gap quasi-crystal edges may be free standing for potentially reduced anchor and substrate mode loss and improved energy confinement compared with traditional surface and slab wave phononic band gap crystals. The proposed phononic band gap quasi-crystal architecture is physically scaled for fabrication as MEMS in a silicon-on-insulator process. Reasonable experimental verification of the model of the electrostatically actuated phononic band gap quasi-crystal architecture is obtained through extensive dynamic harmonic analysis and mode shape topography measurements utilizing optical non-destructive laser-Doppler velocimetry. We have utilized our devices to obtain fundamental information regarding novel transduction mechanisms and behavioral characteristics of the phononic band gap quasi-crystal architecture. Applicability of the phononic band gap quasi-crystal architecture to physical temperature sensors is demonstrated experimentally. Vibration stabilized resonators are demonstrated numerically.

This research was able to identify a wide range of elements present in fresh volcanic ash from a 2010 eruption in Indonesia using varied instrumental neutron activation analysis techniques. The ash was then leached into slightly acidic distilled water meant to simulate rainwater. This thesis focuses both on the methods used to identify the elements present in the ash, as well as the possible impacts of the results. The research included the use of both thermal and epithermal neutron irradiations from the University of Texas's TRIGA research reactor in conjunction with a high purity germanium detector (HPGe) with a Compton suppression system. The leachate was analyzed by an inductively coupled plasma mass spectrometer (ICP-MS), and the results were compared to the original material present in the ash. Several potentially toxic metals and metalloids leached out of the system at relatively high rates. For example, 2.7% of the original antimony present in the ash leached into the simulated rainwater, as well as 1.7% of the original nickel, and 0.71% of the original arsenic. However, the concentrations of the elements identified in the ash were mostly similar to average crustal rock, and the concentrations of the elements identified in the leachate were not determined to be at toxic levels. The total amount of each element released during the eruption was also calculated based on the estimate of 160 million tonnes of ash released during the eruption, which was determined by a different study. / text

The development and fabrication of silicon-based phononic band gap crystals has been gaining interest since phononic band gap crystals have implications in fundamental science and display the potential for application in engineering by providing a relatively new platform for the realization of sensors and signal processing elements. The seminal study of phononic band gap phenomenon for classical elastic wave localization in structures with periodicity in two- or three-physical dimensions occurred in the early 1990’s. Micro-integration of silicon devices that leverage this phenomenon followed from the mid-2000’s until the present. The reported micro-integration relies on exotic piezoelectric transduction, phononic band gap crystals that are etched into semi-infinite or finite-thickness slabs which support surface or slab waves, phononic band gap crystals of numerous lattice constants in dimension and phononic band gap crystal truncation by homogeneous mediums or piezoelectric transducers. The thesis reports, to the best of the author's knowledge, for the first time, the theory, design methodology and experiment of an electrostatically actuated silicon-plate phononic band gap quasi-crystal architecture, which may serve as a platform for the development of a new generation of silicon-integrated sensors, signal processing elements and improved mechanical systems. Electrostatic actuation mitigates the utilization of piezoelectric transducers and provides action at a distance type forces so that the phononic band gap quasi-crystal edges may be free standing for potentially reduced anchor and substrate mode loss and improved energy confinement compared with traditional surface and slab wave phononic band gap crystals. The proposed phononic band gap quasi-crystal architecture is physically scaled for fabrication as MEMS in a silicon-on-insulator process. Reasonable experimental verification of the model of the electrostatically actuated phononic band gap quasi-crystal architecture is obtained through extensive dynamic harmonic analysis and mode shape topography measurements utilizing optical non-destructive laser-Doppler velocimetry. We have utilized our devices to obtain fundamental information regarding novel transduction mechanisms and behavioral characteristics of the phononic band gap quasi-crystal architecture. Applicability of the phononic band gap quasi-crystal architecture to physical temperature sensors is demonstrated experimentally. Vibration stabilized resonators are demonstrated numerically.

No description available.

A microextração líquido-líquido dispersiva baseada no uso de solventes orgânicos (OS-DLLME) vem recebendo grande destaque devido a facilidade de operação, baixo custo, rapidez e um consumo mínimo de solventes. Previamente a OS-DLLME um pré-tratamento do plasma se faz necessário a fim de propiciar a formação de uma adequada fase sedimentada. O levetiracetam (LEV) é um dos fármacos mais prescritos para o tratamento de crises epilépticas parciais e com generalizações secundárias. Assim, foi desenvolvido e validado um método bioanalítico para a quantificação do LEV em amostras de plasma por cromatografia em fase gasosa acoplada à espectrometria de massas (GC/MS). O pré-tratamento das amostras de plasma empregou ultrafiltros Amicon® (poros com tamanho de 10 kDa) que formavam um permeado adequado para a realização da OS-DLLME. A adição de 130 ?L de clorofórmio (solvente extrator) e 400 ?L de isopropanol (solvente dispersor), sem alteração na força iônica e agitação da amostra, proporcionaram 33 % de recuperação do LEV nas amostras de plasma. Tal análise foi realizada usando uma coluna de sílica fundida recoberta com Rtx-5MS (30 m × 0,25 mm x 0,25 ?m) empregando uma rampa de aquecimento. O tempo total de corrida cromatográfica foi de 9 minutos. O método apresentou-se linear no intervalo de concentração de 2 - 80 ?g mL-1 (r >= 0,99), onde os resultados foram ponderados (peso =1/x). A validade da regressão foi confirmada aplicando o teste da falta de ajuste linear. O limite inferior de quantificação (LIQ) foi de 2 ?g mL-1. Os parâmetros de precisão, exatidão, efeito matriz, efeito carry-over e estabilidade demonstraram-se em conformidade com o European Medicines Agency. Outro método foi desenvolvido e validado para a quantificação da risperidona (RSP) e seu metabólito 9-hidroxi-risperidona (9-OH-RSP) em amostras de plasma. A RSP e 9-OH-RSP correspondem a \"fração ativa\" do medicamento responsável pela atividade anticonvulsivante. As amostras de plasma foram pré-tratadas com ácido tricloroacético (TCA 30 %). O sobrenadante límpido foi diluído com solução de NaCl (10 %) e ajustado para o valor de pH 12, no qual foi desenvolvido a OS-DLLME. Foi adicionado um volume de 500 ?L de acetona (solvente dispersor) e 80 ?L de clorobenzeno (solvente extrator). Após otimização da extração, foi alcançado 89 % e 42 % de recuperação da RSP e 9-OH-RSP, respectivamente. Para tais análises foi empregada a cromatografia líquida acoplada à espectrometria de massas sequencial com ionização por eletrospray (LC-MS/MS). Uma coluna Ascentis® C18 (10 cm x 4,6 mm x 2,7 ?m), fase móvel composta por tampão acetato de amônio e acetonitrila, em modo de eluição gradiente, vazão de 500 ?L min-1 e temperatura da coluna de 40 ºC foram empregados. O tempo total da corrida cromatográfica foi de 8 minutos. O método foi linear na faixa de concentração de 5 - 80 ng mL-1 (r >= 0,99), para ambos os analitos. O LIQ foi de 5 ng mL-1. Todos os demais parâmetros estavam em conformidade com a agência regulatória. Ambos os métodos foram aplicados com sucesso em amostras de plasma de paciente em tratamento com LEV ou RSP. Desta forma foi possível demonstrar aplicabilidade dos métodos bioanalíticos desenvolvidos e averiguar a concentração plasmática dos devidos fármacos no paciente / Dispersive liquid-liquid microextraction technique based on the use of organic solvents (OS-DLLME) has received highlighted due to the easily, rapidity, low cost and low consumption of organic solvent. Prior to OS-DLLME, plasma pretreatment is necessary to provide the formation of a suitable settled phase. Levetiracetam (LEV) is one of the most prescribed drugs for the treatment-refractory partial onset seizures with or without secondary generalization. So, it was developed and validated a bioanalytical method for the quantification of LEV in plasma samples by Gas Chromatography Mass Spectrometry (GC/MS). The pretreatment of the plasma samples employed tubes of ultrafiltration Amicon® (pore size 10 kDa) in order to form a suitable permeated to carry out the OS-DLLME. The addition of 130 ?L of chloroform (extraction solvent) and 400 ?L of isopropanol (disperser solvent), without ionic strength and agitation of samples, have reached 33 % of recovery of LEV from plasma samples. This analysis was carried out using a fused silica coated Rtx-5MS column (30 m × 0.25 mm × 0.25 ?m) and a heating ramp. The run time was 9 minutes. The method was linear in the concentration range of 2 - 80 ?g mL-1 (r >= 0.99) and the results were weighted (1/x). The linear regression was confirmed by applying the lack of fit test. The lower limit of quantitation (LLOQ) was 2 ?g mL-1. The precision, accuracy, matrix effect, carry-over and stability were in agreement with European Medicines Agency. Another method was developed and validated for the quantification of risperidone (RSP) and its 9-hydroxy-risperidone metabolite (9-OH-RSP) from plasma samples. The RSP and 9-OH-RSP constitutes the total active moiety responsible for the anticonvulsant activity. Plasma samples were pretreated with trichloroacetic acid (TCA 30%). The clear supernatant was diluted with NaCl solution (10%) and adjusted to pH 12, where was developed the OS-DLLME. It was added 500 ?L of acetone (dispersing solvent) and 80 ?L of chlorobenzene (extraction solvent). After the parameters optimization, the recovery was 89% and 42% for RSP and 9-OH-RSP, respectively. It was employed liquid chromatography-electrospray-tandem-mass spectrometry (LC/ MS/MS). Ascentis® C18 column (10 cm x 4.6 mm x 2.7 ?M), ammonium acetate buffer and acetonitrile as mobile phase in gradient elution mode, at flow rate 500 ?L min-1 and column temperature of 40 °C for this analysis. The run time was 8 minutes. The method was linear in the concentration range 5 - 80 ng mL-1 (r >= 0.99) for both analytes. The LLOQ was 5 ng mL-1. All other parameters were in agreement with the regulatory agency. Both methods have been successfully applied in plasma samples from patient that receive diary doses of LEV or RSP. In this way, it was possible to present the applicability of developed bioanalytical methods and the quantitation of plasmatic concentration of these studied drugs.

<p>Osteoporosis is a major health care problem, by reason of its devastating consequences, in particular hip fractures. Worldwide it has been estimated that the incidence of hip fracture will increase to more than 6 million per year by 2050 compared to 1.7 million per year in 1990. Osteoporosis can be caused by various factors namely, genetic, lifestyle and environmental factors, and since the rising incidence of its consequences is not fully explained by the growing age of the population, there is an urgent need to identify individual causal factors of this condition. </p><p>The present research has focused on aluminium, one potential environmental factor of importance for bone disease, and its possible relation to osteoporosis, since it is known to cause osteoporosis-like bone disease and has been associated with induction of progressive central nervous system diseases.</p><p>Aluminium is the third most common element in the earth’s crust and the most abundant metal (8%). It is widely utilized industrially and it is also naturally present in many foods. Although aluminium is ubiquitous in the human environment, evolution has not given it an essential biological function.</p><p>The aluminium content of bone was measured by inductively coupled mass spectrometry in a large group of patients suffering from hip fractures, high energy fractures and osteoarthrosis. An exponential increase in aluminium content of bone with age was found (p=0.0004). However, no significant association of aluminium in bone with occurrence of hip fracture or dementia could be found, and no indirect evidence was obtained, e.g. through bone mineral density or biomechanical properties, that aluminium is involved in the pathogenesis of osteoporosis. Although we accumulate aluminium in bone throughout our lives, and there are experimental suggestions that aluminium induces premature cell death, the body content of this metal does not seem to influence the overall mortality risk. </p>

Osteoporosis is a major health care problem, by reason of its devastating consequences, in particular hip fractures. Worldwide it has been estimated that the incidence of hip fracture will increase to more than 6 million per year by 2050 compared to 1.7 million per year in 1990. Osteoporosis can be caused by various factors namely, genetic, lifestyle and environmental factors, and since the rising incidence of its consequences is not fully explained by the growing age of the population, there is an urgent need to identify individual causal factors of this condition. The present research has focused on aluminium, one potential environmental factor of importance for bone disease, and its possible relation to osteoporosis, since it is known to cause osteoporosis-like bone disease and has been associated with induction of progressive central nervous system diseases. Aluminium is the third most common element in the earth’s crust and the most abundant metal (8%). It is widely utilized industrially and it is also naturally present in many foods. Although aluminium is ubiquitous in the human environment, evolution has not given it an essential biological function. The aluminium content of bone was measured by inductively coupled mass spectrometry in a large group of patients suffering from hip fractures, high energy fractures and osteoarthrosis. An exponential increase in aluminium content of bone with age was found (p=0.0004). However, no significant association of aluminium in bone with occurrence of hip fracture or dementia could be found, and no indirect evidence was obtained, e.g. through bone mineral density or biomechanical properties, that aluminium is involved in the pathogenesis of osteoporosis. Although we accumulate aluminium in bone throughout our lives, and there are experimental suggestions that aluminium induces premature cell death, the body content of this metal does not seem to influence the overall mortality risk.

No description available.

The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

La perception des emballages alimentaires est passée d’utile à source majeure de contaminants dans les aliments et menace pour l’environnement. La substitution du verre par des con-tenants en plastiques recyclés ou biosourcés réduit l’impact environnemental des boissons embouteillées. La thèse a développé de nouveaux outils de simulation 3D et d’optimisation pour accélérer le prototypage des emballages éco-efficaces pour les boissons alcoolisées. La durée de conservation des boissons, la sécurité sanitaire des matériaux plastiques recyclés, les contraintes mécaniques, et la quantité de déchets sont considérées comme un seul problème d'optimisation multicritères. Les nouvelles bouteilles sont générées virtuellement et itérativement en trois étapes comprenant : i) une [E]valuation multiéchelle des transferts de masse couplés ; ii) une étape de [D]écision validant les contraintes techniques (forme, capacité, poids) et réglementaires (durée de conservation, migrations); iii) une étape globale de ré[S]olution recherchant des solutions de Pareto acceptables. La capacité de prédire la durée de vie des liqueurs dans des conditions réelles a été testée avec succès sur environ 500 miniatures en PET (polyéthylène téréphtalate) sur plusieurs mois. L’ensemble de l’approche a été conçu pour gérer tout transfert de matière couplé (perméation, sorption, migration). La sorption mutuelle est prise en compte via une formulation polynaire de Flory-Huggins. Une formulation gros grain de la théorie des volumes libres de Vrentas et Duda a été développée pour prédire les propriétés de diffusion dans les polymères vitreux de l’eau et des solutés organiques dans des polymères arbitraires (polyesters, polyamides, polyvinyles, polyoléfines). 409 diffusivités issues de la littérature ou mesurées ont été utilisée pour validation. La contribution de la relaxation du PET vitreux a été analysée par sorption différentielle (binaire et ternaire) de 25 à 50 °C. Une partie du code source sera partagé afin d'encourager l'intégration de davantage de paramètres affectant la durée de conservation des boissons et des produits alimentaires (cinétique d'oxydation, piégeage d'arômes). / The view of plastic food packaging turned from useful to a major source of contaminants in food and an environmental threat. Substituting glass by recycled or biosourced plastic containers reduces environmental impacts for bottled beverages. The thesis developed a 3D computational and optimization framework to accelerate the prototyping of eco-efficient packaging for alcoholic beverages. Shelf-life, food safety, mechanical constraints, and packaging wastes are considered into a single multicriteria optimization problem. New bottles are virtually generated within an iterative three steps process involving: i) a multiresolution [E]valuation of coupled mass transfer; ii) a [D]ecision step validating technical (shape, capacity, weight) and regulatory (shelf-life, migrations) constraints; iii) a global [Solving] step seeking acceptable Pareto solutions. The capacity to predict shelf-life of liquors in real conditions was tested successfully on ca. 500 hundred bottle min iatures in PET (polyethylene terephthalate) over several months. The entire approach has been designed to manage any coupled mass transfer (permeation, sorption, migration). Mutual sorption is considered via polynary Flory-Huggins formulation. A blob formulation of the free-volume theory of Vrentas and Duda was developed to predict the diffusion properties in glassy polymers of water and organic solutes in arbitrary polymers (polyesters, polyamides, polyvinyls, polyolefins). The validation set included 433 experimental diffusivities from literature and measured in this work. The contribution of polymer relaxation in glassy PET was analyzed in binary and ternary differential sorption using a cosorption microbalance from 25 to 50°C. Part of the framework will be released as an open-source project to encourage the integration of more factors affecting the shelf-life of beverages and food products (oxidation kinetics, aroma scalping).