Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 130-131). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin, 1967. / Typescript. Vita. Includes reprints of 3 articles from the Journal of chemical physics and the Journal of physical chemistry by the author and others. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Magister Scientiae - MSc (Chemistry) / Electrochemical platforms were developed based on pencil graphite electrodes (PGEs) modified electrochemically with reduced graphene oxide metal nanoparticles (ERGO-metalNPs) composite and used for the high-sensitivity determination of Bisphenol A (BPA) in water samples. Synergistic effects of both reduced Graphene Oxide sheets and metal nanoparticles on the performance of the pencil graphite electrode (PGE) were demonstrated in the oxidation of BPA by differential pulse voltammetry (DPV). A solution of graphene oxide (GO) 1 mg mL-1 and 15 ppm of metal stock solutions (1,000 mg L-1, atomic absorption standard solution) (Antimony or Gold) was prepared and after sonication deposited onto pencil graphite electrodes by cyclic voltammetry reduction. Different characterization techniques such as FT-IR, HR-SEM, XRD and Raman spectroscopy were used to characterize the GO and ERGO-metalNPs. Parameters that influence the electroanalytical response of the ERGO-SbNPs and ERGO-AuNPs such as, pH, deposition time, deposition potential, purging time were investigated and optimized. Well-defined, reproducible peaks with detection limits of 0.0125 ?M and 0.062 ?M were obtained for BPA using ERGO-SbNPs and ERGO-AuNPs respectively. The rGO-metalNPs-PGE was used for the quantification of BPA in tap water sample and proved to be suitable for the detection of BPA below USEPA prescribed drinking water standards of 0.087 ?M. / 2021-12-31

Magister Scientiae - MSc (Chemistry) / Electrochemical platforms were developed based on pencil graphite electrodes (PGEs) modified electrochemically with reduced graphene oxide metal nanoparticles (ERGO–metalNPs) composite and used for the high-sensitivity determination of Bisphenol A (BPA) in water samples. Synergistic effects of both reduced Graphene Oxide sheets and metal nanoparticles on the performance of the pencil graphite electrode (PGE) were demonstrated in the oxidation of BPA by differential pulse voltammetry (DPV). A solution of graphene oxide (GO) 1 mg mL-1 and 15 ppm of metal stock solutions (1,000 mg L-1, atomic absorption standard solution) (Antimony or Gold) was prepared and after sonication deposited onto pencil graphite electrodes by cyclic voltammetry reduction. Different characterization techniques such as FT-IR, HR-SEM, XRD and Raman spectroscopy were used to characterize the GO and ERGO–metalNPs. Parameters that influence the electroanalytical response of the ERGO–SbNPs and ERGO–AuNPs such as, pH, deposition time, deposition potential, purging time were investigated and optimized. Well-defined, reproducible peaks with detection limits of 0.0125 μM and 0.062 μM were obtained for BPA using ERGO–SbNPs and ERGO–AuNPs respectively. The rGO-metalNPs–PGE was used for the quantification of BPA in tap water sample and proved to be suitable for the detection of BPA below USEPA prescribed drinking water standards of 0.087 μM.

Additive Manufacturing (AM), over the years, has seen a tremendous amount of research for improving the manufacturability of materials into final products. The main advantages of additive manufacturing are the minimizing of waste material as it is an additive process. As well as the ability to create custom low-volume products without the need for creation of expensive tooling or programming before manufacturing begins. Because of these advantages, however, AM is susceptible to unique challenges in the quality side of manufacturing. These challenges include minimizing and detecting defects during the build. The focus of this research looks at the capability of using Pulse Thermography (PT), a nondestructive testing method, with longer than typical pulse length on additively manufactured parts for surface and sub-surface defect detection as well as thermal property determination based on a known void depth. The first and second part of this research will look at a range of pulse lengths greater than 100ms to determine if the previously defined assumption is necessary for accurate defect detection. The significance of increasing the pulse length is to have the ability to increase the overall energy input into the part without having to increase the power. Allowing for the capability of defect detection for both shallow and deeper defects with the same overall setup. One-dimensional simulations r using Forward Time Center Space (FTCS) approximation, show that the assumption of an instantaneous pulse is relative, and defects can be accurately calculated within a range of pulse lengths. Based on the simulations, experimentation was conducted to determine the capability of calculating sub-surface defect depths with a longer pulse on a FDM printed ABS part with 100% in fill. The defect depths will range from 0.3mm to 1.8mm and the widths of the defects used for depth calculation will be 8x8mm. Results of the experiments show that even with FDM printed parts defect depths were accurately calculated up to a depth of 1.2mm. The third aspect of this research looks at the infrared reflections emitting off the surface during the longer pulse. With a longer pulse length, there is more time for the infrared camera to collect thermograms of the surface during the pulse. It was noticed during sub-surface defect detection that the infrared reflections paint a picture of the surface characteristics of the part. Characteristics that include surface imperfections not intended in the original build parameters such as under extrusions and cracks. Defects as small as 150μm with a thermal pixel resolution 75μm are detected. The third and final aspect of this research looks at the ability to use PT with a longer pulse to determine thermal properties of a binder jetted additively manufactured part as well as packing factors that may be otherwise be unknown. When a product is binder jetted a chemical binder is added to the powder layer by layer until a product is formed.

ALBUQUERQUE, André Cardoso. Germinação e estabelecimento inicial de espécies congêneres de ambiente seco. 2015. 34 f. Dissertação (Mestrado em ecologia e recursos naturais)- Universidade Federal do Ceará, Fortaleza-CE, 2015. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-05-19T17:59:49Z No. of bitstreams: 1 2015_dis_acalbuquerque.pdf: 957472 bytes, checksum: 8e9d6447f163459cf0f8fbfa85a192fb (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-05-27T20:07:17Z (GMT) No. of bitstreams: 1 2015_dis_acalbuquerque.pdf: 957472 bytes, checksum: 8e9d6447f163459cf0f8fbfa85a192fb (MD5) / Made available in DSpace on 2016-05-27T20:07:17Z (GMT). No. of bitstreams: 1 2015_dis_acalbuquerque.pdf: 957472 bytes, checksum: 8e9d6447f163459cf0f8fbfa85a192fb (MD5) Previous issue date: 2015 / In severe abiotic conditions, environmental filter selects phylogenetically related species. This trend promotes the problem of competitive exclusion, differentiation the regeneration niche for coexistence mechanism. There are studies of germination requirements and initial establishment of herbaceous species that indicate interspecific differences related to specialization pulse or interpulse, contributing to the coexistence in plant communities of arid and semi-arid environments. But there is a lack of studies seeking evidence for woody species. Seeking to fill the gap investigate differences in seed characteristics, germination and early development in two species of Mimosa. We found biometrics and water content in the seeds; germination under different temperatures; germination under different degrees of water stress; imbibition curve and initial development in lighting and irrigation treatments. Mimosa casealpiniifolia Benth. presented interpulse features on germination and early development, because of the higher seed size (larger amount of reserves); higher water content in the seed; Conservative soaking in water absorption curve; resistance to more intense water stress and better initial growth in water treatment interpulse than wrist. Mimosa tenuiflora Benth. showed characteristics of expertise to the wrists on germination and early development: small amount of reserves; low moisture content; rapid and greater water absorption in the imbibition curve; less resistance to water stress and better initial growth in pulse than interpulse. We conclude that the congeners studied tree species differ in the characteristics of seeds and germination; and have different initial responses and the development of treatments and interpulse pulse, so that indicates a performance difference in different moments of the water system; which can be related to the coexistence of these species. / Em condições abióticas severas, o filtro ambiental seleciona espécies filogeneticamente aparentadas. Essa tendência promove o problema de exclusão competitiva, sendo a diferenciação no nicho de regeneração um mecanismo para a coexistência. Existem estudos dos requerimentos de germinação e estabelecimento inicial de espécies herbáceas que indicam diferenças interespecíficas relacionadas à especialização a pulso ou interpulsos, contribuindo para a coexistência em comunidades vegetais de ambientes áridos e semiáridos. Porém existe uma falta de estudos buscando evidências para espécies lenhosas. Buscando preencher essa lacuna, investigamos diferenças em características de sementes, germinação e desenvolvimento inicial em duas espécies de Mimosa. Verificamos biometria e conteúdo de água nas sementes; germinação sob diferentes temperaturas; germinação sob diferentes graus de estresse hídrico; curva de embebição e desenvolvimento inicial sob tratamentos de luminosidade e irrigação. Mimosa casealpiniifolia Benth. apresentou características de interpulso na germinação e no desenvolvimento inicial, devido ao maior tamanho das sementes (maior quantidade de reservas); maior teor de água na semente; absorção conservadora de água na curva de embebição; resistência a estresse hídrico mais intenso e crescimento inicial melhor em tratamento hídrico de interpulso do que pulso. Mimosa tenuiflora Benth. apresentou características de especialização aos pulsos na germinação e no desenvolvimento inicial: pequena quantidade de reservas; baixo teor de umidade; rápida e maior absorção de água na curva de embebição; menor resistência ao estresse hídrico e crescimento inicial melhor em pulso do que interpulso. Concluímos que as espécies arbóreas congêneres estudadas divergem nas características das sementes e germinação; e apresentam respostas de desenvolvimento inicial distinta quanto aos tratamentos de pulso e interpulso, de forma que indica uma diferenciação de desempenho em diferentes momentos deste regime hídrico; que pode estar relacionada com a coexistência dessas espécies.

O biodiesel vem se consolidando como combustível alternativo devido às suas vantagens e importância econômica. Conforme seu percentual no diesel comercial cresce, o monitoramento da qualidade se torna cada vez mais importante para uma comercialização segura. No entanto, a estabilidade oxidativa do biodiesel é inferior à do diesel fóssil, assim antioxidantes sintéticos, tais como BHA, BHT, PG e TBHQ, são adicionados para prevenir a degradação do mesmo, evitando danos ao sistema de combustão automotivo. Os métodos para avaliar a estabilidade oxidativa e a quantidade de antioxidantes são em geral demorados, requerem preparação amostral ou equipamentos de alto custo. Com o objetivo de contornar tais problemas, neste trabalho foi aplicada uma metodologia para análise direta de antioxidantes em amostras de biodiesel por meio de voltametria de pulso diferencial. Conjuntamente, foi estudada a viabilidade da associação dessa metodologia com técnicas quimiométricas para a determinação simultânea desses antioxidantes em misturas de antioxidantes em biodiesel. Para permitir uma análise direta, sem extração e pré-concentração dos analitos, o biodiesel foi diluído em meio etanólico. Medidas de voltametria de pulso diferencial para cada antioxidante individualmente mostraram relação linear entre as concentrações dos antioxidantes e a corrente de oxidação. Os limites de detecção individuais obtidos foram de 20,5 mg L-1 para BHA, 32,4 mg L-1 para BHT, 35,5 mg L-1 para PG e 26,5 mg L-1 para TBHQ. A modelagem quimiométrica foi aplicada por meio das ferramentas Mínimos Quadrados Clássico (CLS), Mínimos Quadrados Parciais (PLS), Redes Neuronais Artificiais (ANN), Componentes Principais-Redes Neuronais Artificiais (PC-ANN) e Árvore de Decisão-Redes Neuronais Artificiais (DT-ANN). O modelo construído por PLS se mostrou melhor quando comparado à modelagem por CLS. O modelo construído por ANN’s sem seleção de dados de entrada apresentou erros semelhantes ao PLS. Quando a redução da quantidade de dados de entrada foi aplicada em conjunto com ANN’s através de Análise por Componentes Principais (PCA) e DT, a aplicação de PCA levou a aumento de 10,2% no erro de predição, enquanto que na seleção por DT os erros de predição foram reduzidos em 8,5%. A determinação simultânea dos quatro compostos pelo modelo DT-ANN apresentou precisão satisfatória, com recuperação de 98% para BHA, 97% para BHT, 103% para PG e 100% para TBHQ, o que indica que a técnica analítica e a modelagem quimiométrica são viáveis e promissoras para aplicação no controle de qualidade do biodiesel, bem como em análises de monitoramento nas plantas industriais. / Biodiesel is becoming established as an alternative fuel because its advantages and economic importance. As the levels of biodiesel in commercial diesel grows, quality monitoring becomes increasingly important for safe marketing. However, the oxidative stability of biodiesel is smaller than that of fossil diesel and synthetic antioxidants such as BHA, BHT, PG and TBHQ are added to it in order to prevent its degradation, avoiding damage to the automotive combustion system. Methods for evaluating oxidative stability and the amount of antioxidants are usually time-consuming, require sample preparation or expensive equipment. In order to overcome such problems, in this work a methodology was applied for direct analysis of antioxidants in biodiesel samples by means of differential pulse voltammetry. The viability of associating this methodology with chemometric techniques was studied for the simultaneous determination of these antioxidants in biodiesel. To allow a direct analysis, without extraction and preconcentration of analytes, biodiesel was diluted in ethanolic medium. Differential pulse voltammetric measurements for each antioxidant individually showed a linear relationship between antioxidant concentrations and oxidation current. The individual detection limits were 20,5 mg L-1 for BHA, 32,4 mg L-1 for BHT, 35,5 mg L-1 for PG and 26,5 mg L-1 for TBHQ. The chemometric modeling was applied using the Classical Least Squares (CLS), Partial Least Squares (PLS), Artificial Neural Networks (ANN), Principal Component-Artificial Neural Networks (PC-ANN) and Decision Tree-Artificial Neural Networks (DT-ANN) techniques. The model constructed by PLS was better than that obtained with CLS. The model constructed by ANN’s without input selection presented similar deviations in comparison to PLS. When amount of input data reduction was applied together with ANNs through Principal Component Analysis (PCA) and DT, the PCA application led to a 10.2% increase in prediction error, whereas in the selection by DT prediction errors were reduced by 8,5%. The simultaneous determination of the four compounds by the DT-ANN model presented satisfactory accuracy with 98% recovery for BHA, 97% for BHT, 103% for PG and 100% for TBHQ, indicating that the analytical technique and the chemometric modeling are feasible and promising for application in biodiesel quality control, as well as in monitoring analyzes in the industrial plants.

Smart watches in future will have smart wristband. This work analyses properties of new developed capacitive wristband sensor that measures ballistocardiogram (BCG) from single point on the wrist. In addition, it considers applications of this sensor to monitoring heart rate variability. Another application is in estimating changes (trend) in systolic blood pressure continuously when combined with lead one electrocardiogram (ECG). BP is one of the vital signs that indicates the health condition. It is commonly measured by cuff-based monitor using either auscultatory or oscillometric method. Cuff-based BP monitor is not portable and unable to measure BP continuously which means it is difficult to attach BP monitoring function on a wearable device. Significant research is conducted in estimating BP from pulse transit time (PTT) mathematically which would enable the cuffless BP measurement. In this work, a new time reference, RJ interval, which is the time delay between ECG and BCG signal peaks was tested whether it can be used as a surrogate of PTT in cuffless BP estimation. Based on the study done on 10 healthy people, it was shown that RJ intervals can be useful in evaluating trends of systolic blood pressure.

O biodiesel vem se consolidando como combustível alternativo devido às suas vantagens e importância econômica. Conforme seu percentual no diesel comercial cresce, o monitoramento da qualidade se torna cada vez mais importante para uma comercialização segura. No entanto, a estabilidade oxidativa do biodiesel é inferior à do diesel fóssil, assim antioxidantes sintéticos, tais como BHA, BHT, PG e TBHQ, são adicionados para prevenir a degradação do mesmo, evitando danos ao sistema de combustão automotivo. Os métodos para avaliar a estabilidade oxidativa e a quantidade de antioxidantes são em geral demorados, requerem preparação amostral ou equipamentos de alto custo. Com o objetivo de contornar tais problemas, neste trabalho foi aplicada uma metodologia para análise direta de antioxidantes em amostras de biodiesel por meio de voltametria de pulso diferencial. Conjuntamente, foi estudada a viabilidade da associação dessa metodologia com técnicas quimiométricas para a determinação simultânea desses antioxidantes em misturas de antioxidantes em biodiesel. Para permitir uma análise direta, sem extração e pré-concentração dos analitos, o biodiesel foi diluído em meio etanólico. Medidas de voltametria de pulso diferencial para cada antioxidante individualmente mostraram relação linear entre as concentrações dos antioxidantes e a corrente de oxidação. Os limites de detecção individuais obtidos foram de 20,5 mg L-1 para BHA, 32,4 mg L-1 para BHT, 35,5 mg L-1 para PG e 26,5 mg L-1 para TBHQ. A modelagem quimiométrica foi aplicada por meio das ferramentas Mínimos Quadrados Clássico (CLS), Mínimos Quadrados Parciais (PLS), Redes Neuronais Artificiais (ANN), Componentes Principais-Redes Neuronais Artificiais (PC-ANN) e Árvore de Decisão-Redes Neuronais Artificiais (DT-ANN). O modelo construído por PLS se mostrou melhor quando comparado à modelagem por CLS. O modelo construído por ANN’s sem seleção de dados de entrada apresentou erros semelhantes ao PLS. Quando a redução da quantidade de dados de entrada foi aplicada em conjunto com ANN’s através de Análise por Componentes Principais (PCA) e DT, a aplicação de PCA levou a aumento de 10,2% no erro de predição, enquanto que na seleção por DT os erros de predição foram reduzidos em 8,5%. A determinação simultânea dos quatro compostos pelo modelo DT-ANN apresentou precisão satisfatória, com recuperação de 98% para BHA, 97% para BHT, 103% para PG e 100% para TBHQ, o que indica que a técnica analítica e a modelagem quimiométrica são viáveis e promissoras para aplicação no controle de qualidade do biodiesel, bem como em análises de monitoramento nas plantas industriais. / Biodiesel is becoming established as an alternative fuel because its advantages and economic importance. As the levels of biodiesel in commercial diesel grows, quality monitoring becomes increasingly important for safe marketing. However, the oxidative stability of biodiesel is smaller than that of fossil diesel and synthetic antioxidants such as BHA, BHT, PG and TBHQ are added to it in order to prevent its degradation, avoiding damage to the automotive combustion system. Methods for evaluating oxidative stability and the amount of antioxidants are usually time-consuming, require sample preparation or expensive equipment. In order to overcome such problems, in this work a methodology was applied for direct analysis of antioxidants in biodiesel samples by means of differential pulse voltammetry. The viability of associating this methodology with chemometric techniques was studied for the simultaneous determination of these antioxidants in biodiesel. To allow a direct analysis, without extraction and preconcentration of analytes, biodiesel was diluted in ethanolic medium. Differential pulse voltammetric measurements for each antioxidant individually showed a linear relationship between antioxidant concentrations and oxidation current. The individual detection limits were 20,5 mg L-1 for BHA, 32,4 mg L-1 for BHT, 35,5 mg L-1 for PG and 26,5 mg L-1 for TBHQ. The chemometric modeling was applied using the Classical Least Squares (CLS), Partial Least Squares (PLS), Artificial Neural Networks (ANN), Principal Component-Artificial Neural Networks (PC-ANN) and Decision Tree-Artificial Neural Networks (DT-ANN) techniques. The model constructed by PLS was better than that obtained with CLS. The model constructed by ANN’s without input selection presented similar deviations in comparison to PLS. When amount of input data reduction was applied together with ANNs through Principal Component Analysis (PCA) and DT, the PCA application led to a 10.2% increase in prediction error, whereas in the selection by DT prediction errors were reduced by 8,5%. The simultaneous determination of the four compounds by the DT-ANN model presented satisfactory accuracy with 98% recovery for BHA, 97% for BHT, 103% for PG and 100% for TBHQ, indicating that the analytical technique and the chemometric modeling are feasible and promising for application in biodiesel quality control, as well as in monitoring analyzes in the industrial plants.

abstract: ABSTRACT The D flip flop acts as a sequencing element while designing any pipelined system. Radiation Hardening by Design (RHBD) allows hardened circuits to be fabricated on commercially available CMOS manufacturing process. Recently, single event transients (SET's) have become as important as single event upset (SEU) in radiation hardened high speed digital designs. A novel temporal pulse based RHBD flip-flop design is presented. Temporally delayed pulses produced by a radiation hardened pulse generator design samples the data in three redundant pulse latches. The proposed RHBD flip-flop has been statistically designed and fabricated on 90 nm TSMC LP process. Detailed simulations of the flip-flop operation in both normal and radiation environments are presented. Spatial separation of critical nodes for the physical design of the flip-flop is carried out for mitigating multi-node charge collection upsets. The proposed flip-flop is also used in commercial CAD flows for high performance chip designs. The proposed flip-flop is used in the design and auto-place-route (APR) of an advanced encryption system and the metrics analyzed. / Dissertation/Thesis / M.S. Electrical Engineering 2014