Introdução. O consumo de açúcares aumentou consideravelmente nas últimas décadas, bem como a incidência e a prevalência da obesidade, gerando a elaboração de recomendações para moderá-lo. Os açúcares contribuem para a palatabilidade dos alimentos, podendo também aumentar sua densidade energética (DE), outro fator de risco para obesidade. Uma alternativa seria a substituição por adoçantes não calóricos, que também aumentam a palatabilidade dos alimentos, porém são isentos calorias. No entanto, ainda não existe consenso a respeito das implicações desta substituição principalmente na redução da ingestão energética e do peso corporal. Objetivo. Identificar a DE da dieta, a ingestão energética total e de macronutrientes, segundo consumo de adoçantes e/ou alimentos processados com adoçantes por adultos e idosos. Métodos. Estudo transversal, no qual foram coletados dados de sexo; idade; peso e estatura, para cálculo do IMC; consumo de adoçantes, por questionário adaptado e pelo recordatório de 24 horas, foram calculadas as médias de DE, de ingestão energética total e de macronutrientes. Para verificar associação entre variáveis independentes (idade, sexo, IMC, uso de adoçantes não calóricos) com a dependente \"classificação da DE foi realizada regressão logística, considerando dietas com alta DE aquelas com 1,5 Kcal/g ou mais. Para comparação das médias de ingestão energética e de macronutrientes, entre usuários de adoçantes e não usuários, foi utilizado o Teste t de Student (p 0,05) pelo Stata 10.0. Resultados. Participaram do estudo 168 indivíduos, com idade média de 54,8 anos (DP = 14,9 anos), sendo 84,5 por cento do sexo feminino, 67,9 por cento com sobrepeso ou obesidade e 44,1 por cento usuários de adoçantes. A média da DE das dietas de usuários de adoçantes foi 1,15 Kcal/g (IC 95 por cento [1,11; 1,19]), e de não usuários 1,28 Kcal/g (IC 95 por cento [1,23; 1,33]). Para regressão logística, as variáveis contínuas, idade e IMC, foram categorizadas, porém esta última não permaneceu no modelo final (p > 0,10). Apesar de não significativo, a variável sexo permaneceu no modelo como ajuste. A classificação da idade (p = 0,042) e o uso de adoçantes (p = 0,002) apresentaram associação com os menores valores de DE. Não foi encontrada diferença nas médias de ingestão energética e de macronutrientes entre os grupos. Conclusão. Uso de adoçantes se associou com menores valores de DE, mas não houve diferença no consumo energético total e de macronutrientes entre grupos / The consumption of sugar has increased considerably in recent decades, as well as the incidence and prevalence of obesity, leading the development of recommendations to moderate this consumption. Sugars contribute to the palatability of food, but may also increase their energy density (ED), which is an important obesitys risk factor. An alternative would be replacing sugar by non-caloric sweeteners, which increase the palatability of foods, but with free calories. However, the implications of this substitution in reducing energy intake and body weight are controversial. Objective. Identify the ED of diets, the total energy intake and macronutrient consumption according to the consumption of sweeteners and/or processed foods with sweeteners by adults and elderly. Methods. A cross sectional study, that collected data on gender, age, weight and height, to calculate BMI, consumption of non-caloric sweeteners, by questionnaire and with data from 24-hour recall, were calculated the average of ED, total energy intake and total macronutrient intake. Logistic regression was performed to assess the association between independent variables (age, gender, BMI, use of non-caloric sweeteners) and the dependent classification of ED, considering diets with high ED those with 1.5 kcal/g or more. To compare the means of total energy intake and total macronutrient intake, among noncaloric sweeteners users and nonusers, was used the Students t test (p 0.05) by Stata 10.0. Results. Were collected data form 168 individuals, with an average age of 54.8 years (SD = 14.9 years), 84.5 per cent female, 67.9 per cent overweight or obese and 44.1 per cent users of sweeteners. The mean of ED diets of non-caloric sweeteners users was 1.15 kcal/g (CI 95 per cent [1.11; 1.19]), and 1.28 Kcal/g (CI 95 per cent [1.23; 1.33]) for non-users. For logistic regression the continuous variables, BMI and age, were categorized, but the former did not remained in the final model. Although the variable gender was not significant it remained in the model for adjustment. The classification of age (p = 0.042) and the use of sweeteners (p = 0.002) were associated with lower values of ED. No difference was found in the means of total energy intake and total macronutrient intake between the groups. Conclusion. The use of sweeteners was associated with lower values of ED, but there was no difference in the means of total energy intake and total macronutrient intake between the groups

Made available in DSpace on 2017-07-21T19:25:51Z (GMT). No. of bitstreams: 1 Fernando Camilotti.pdf: 2665595 bytes, checksum: 785710d19df5786aef751b2d0407abea (MD5) Previous issue date: 2016-03-11 / The use of fiber posts in endodontic teeth restorations has been very frequent. These posts have conical shape and it is usually formed by glass fibers packaged in epoxy resin. Microscopy studies were conducted to investigate the structure of four models of fiberglass posts manufactured by FGM (DC 0.5, DC1, DC2 and DC3 models), and it was possible to verify inhomogeneities. The models of posts used in this study are translucent and, in clinical use, it is cemented into the tooth with light curing activated resin. During the clinical procedure of cementing a post in the tooth, light from a curing light impinge at the base of the post transmitting light to its interior. Part of this light is spread out by the side surface of the post. This study proposes a new methodology in order to investigate the spreading of light by endodontic posts in the orthogonal direction to its axis. This methodology fills out an dentist demand, e by means of it, it is possible to obtain light intensity profiles spread out along the length of a post. Comparing to previously published methods, this one uses the phase sensitive detection and the possibility to control the optical aperture in the experiment. The resulting profiles show a like exponential decay of light along the post, which allow us to obtain an linear attenuation coefficient for the different posts models studied. From the experimental results it is shown a way to calculate the light density of volumetric energy inside the post. The advantages of this new method are: (a) the results lead to much better characterization of the samples with more measured points and (b) the small optical aperture that provides better resolution. / O uso de pinos endodônticos em restaurações de dentes tem sido muito frequente. Estes pinos são formados, em geral, por fibras de vidro envolvidas e compactadas em epóxi, possuindo um formato cônico. Estudos de microscopia foram realizados para investigar a estrutura de quatro modelos de pinos de fibra de vidro do fabricante FGM (modelos DC 0.5, DC1, DC2 e DC3), e constatou-se falta de homogeneidade. Os modelos de pinos usados neste trabalho são transparentes e, no uso clínico, são cimentados no interior do dente com uma resina que tem a cura ativada por luz. No procedimento de cimentação de um pino no dente, a luz de um aparelho fotopolimerizador incide na base do pino transmitindo luz para seu interior. Parte desta luz é espalhada pela superfície lateral do pino. Este trabalho propõem um novo método para investigar o espalhamento da luz por pino endodônticos, na direção ortogonal ao seu eixo. Esta investigação atende uma demanda da odontologia, e como resultado do novo método, obtemos perfis de intensidade de luz espalhada ao longo do comprimento de um pino. O diferencial deste novo método, em relação aos métodos já publicados, é o emprego da detecção sensível à fase e a possibilidade de controlar a abertura ótica no experimento. Os perfis de espalhamento apontam para uma queda do tipo exponencial da luz ao longo do pino e isso possibilitou obter coeficientes de atenuação lineares para os diferentes modelos de pinos estudados. Com os resultados experimentais, é indicada uma forma de calcular a densidade volumétrica média de energia luminosa no interior do pino. As vantagens deste novo método são: (a) os resultados apresentam melhor caracterização das amostras por apresentar mais pontos de medida e (b) pela abertura ótica ser pequena ocorre a garantia de uma melhor resolução de medida.

Introdução. O consumo de açúcares aumentou consideravelmente nas últimas décadas, bem como a incidência e a prevalência da obesidade, gerando a elaboração de recomendações para moderá-lo. Os açúcares contribuem para a palatabilidade dos alimentos, podendo também aumentar sua densidade energética (DE), outro fator de risco para obesidade. Uma alternativa seria a substituição por adoçantes não calóricos, que também aumentam a palatabilidade dos alimentos, porém são isentos calorias. No entanto, ainda não existe consenso a respeito das implicações desta substituição principalmente na redução da ingestão energética e do peso corporal. Objetivo. Identificar a DE da dieta, a ingestão energética total e de macronutrientes, segundo consumo de adoçantes e/ou alimentos processados com adoçantes por adultos e idosos. Métodos. Estudo transversal, no qual foram coletados dados de sexo; idade; peso e estatura, para cálculo do IMC; consumo de adoçantes, por questionário adaptado e pelo recordatório de 24 horas, foram calculadas as médias de DE, de ingestão energética total e de macronutrientes. Para verificar associação entre variáveis independentes (idade, sexo, IMC, uso de adoçantes não calóricos) com a dependente \"classificação da DE foi realizada regressão logística, considerando dietas com alta DE aquelas com 1,5 Kcal/g ou mais. Para comparação das médias de ingestão energética e de macronutrientes, entre usuários de adoçantes e não usuários, foi utilizado o Teste t de Student (p 0,05) pelo Stata 10.0. Resultados. Participaram do estudo 168 indivíduos, com idade média de 54,8 anos (DP = 14,9 anos), sendo 84,5 por cento do sexo feminino, 67,9 por cento com sobrepeso ou obesidade e 44,1 por cento usuários de adoçantes. A média da DE das dietas de usuários de adoçantes foi 1,15 Kcal/g (IC 95 por cento [1,11; 1,19]), e de não usuários 1,28 Kcal/g (IC 95 por cento [1,23; 1,33]). Para regressão logística, as variáveis contínuas, idade e IMC, foram categorizadas, porém esta última não permaneceu no modelo final (p > 0,10). Apesar de não significativo, a variável sexo permaneceu no modelo como ajuste. A classificação da idade (p = 0,042) e o uso de adoçantes (p = 0,002) apresentaram associação com os menores valores de DE. Não foi encontrada diferença nas médias de ingestão energética e de macronutrientes entre os grupos. Conclusão. Uso de adoçantes se associou com menores valores de DE, mas não houve diferença no consumo energético total e de macronutrientes entre grupos / The consumption of sugar has increased considerably in recent decades, as well as the incidence and prevalence of obesity, leading the development of recommendations to moderate this consumption. Sugars contribute to the palatability of food, but may also increase their energy density (ED), which is an important obesitys risk factor. An alternative would be replacing sugar by non-caloric sweeteners, which increase the palatability of foods, but with free calories. However, the implications of this substitution in reducing energy intake and body weight are controversial. Objective. Identify the ED of diets, the total energy intake and macronutrient consumption according to the consumption of sweeteners and/or processed foods with sweeteners by adults and elderly. Methods. A cross sectional study, that collected data on gender, age, weight and height, to calculate BMI, consumption of non-caloric sweeteners, by questionnaire and with data from 24-hour recall, were calculated the average of ED, total energy intake and total macronutrient intake. Logistic regression was performed to assess the association between independent variables (age, gender, BMI, use of non-caloric sweeteners) and the dependent classification of ED, considering diets with high ED those with 1.5 kcal/g or more. To compare the means of total energy intake and total macronutrient intake, among noncaloric sweeteners users and nonusers, was used the Students t test (p 0.05) by Stata 10.0. Results. Were collected data form 168 individuals, with an average age of 54.8 years (SD = 14.9 years), 84.5 per cent female, 67.9 per cent overweight or obese and 44.1 per cent users of sweeteners. The mean of ED diets of non-caloric sweeteners users was 1.15 kcal/g (CI 95 per cent [1.11; 1.19]), and 1.28 Kcal/g (CI 95 per cent [1.23; 1.33]) for non-users. For logistic regression the continuous variables, BMI and age, were categorized, but the former did not remained in the final model. Although the variable gender was not significant it remained in the model for adjustment. The classification of age (p = 0.042) and the use of sweeteners (p = 0.002) were associated with lower values of ED. No difference was found in the means of total energy intake and total macronutrient intake between the groups. Conclusion. The use of sweeteners was associated with lower values of ED, but there was no difference in the means of total energy intake and total macronutrient intake between the groups

The work presents investigations into the development of a fuel-powered compact SMA actuator system. For the final SMA actuator, the K-alloy SMA strip (0.9 mm x 2.5 mm), actuated by a forced convection heat transfer mechanism, was embedded in a rectangular channel. In this channel, a rectangular piston, with a slot to accommodate the SMA strip, ran along the strip and was utilized to prevent mixing between the hot and the cold fluid in order to increase the energy density of the system. The fuel, such as propane, was utilized as main energy source in order to achieve high energy and power densities of the SMA actuator system. Numerical analysis was carried out to determine optimal channel geometry and to estimate maximum available force, strain and actuation frequency. Multi-channel combustor/heat exchanger and micro-tube heat exchanger were designed and tested to achieve high heat transfer rate and high compactness. The final SMA actuator system was composed of pumps, valves, bellows, multi-channel combustor/heat exchanger, micro-tube heat exchanger and control unit. The experimental tests of the final system resulted in 250 N force with 2 mm displacement and 1.0 Hz actuation frequency in closed-loop operation, in which the hot and the cold fluid were re-circulated by pumps.

Electromechanical transducers based on elastomer capacitors are presently considered for many soft actuation applications, due to their large reversible deformation in response to electric field induced electrostatic pressure. The high operating voltage of such devices is currently a large drawback, hindering their use in applications such as biomedical devices and biomimetic robots, however, they could be improved with a careful design of their material properties. The main targets for improving their properties are increasing the relative permittivity of the active material, while maintaining high electric breakdown strength and low stiffness, which would lead to enhanced electrostatic storage ability and hence, reduced operating voltage. Improvement of the functional properties is possible through the use of nanocomposites. These exploit the high surface-to-volume ratio of the nanoscale filler, resulting in large effects on macroscale properties. This thesis explores several strategies for nanomaterials design. The resulting nanocomposites are fully characterized with respect to their electrical and mechanical properties, by use of dielectric spectroscopy, tensile mechanical analysis, and electric breakdown tests. First, nanocomposites consisting of high permittivity rutile TiO2 nanoparticles dispersed in thermoplastic block copolymer SEBS (poly-styrene-coethylene-co-butylene-co-styrene) are shown to exhibit permittivity increases of up to 3.7 times, leading to 5.6 times improvement in electrostatic energy density, but with a trade-off in mechanical properties (an 8-fold increase in stiffness). The variation in both electrical and mechanical properties still allows for electromechanical improvement, such that a 27 % reduction of the electric field is found compared to the pure elastomer. Second, it is shown that the use of nanofiller conductive particles (carbon black (CB)) can lead to a strong increase of relative permittivity through percolation, however, with detrimental side effects. These are due to localized enhancement of the electric field within the composite, which leads to sharp reductions in electric field strength. Hence, the increase in permittivity does not make up for the reduction in breakdown strength in relation to stored electrical energy, which may prohibit their practical use. Third, a completely new approach for increasing the relative permittivity and electrostatic energy density of a polymer based on 'molecular composites' is presented, relying on chemically grafting soft π-conjugated macromolecules to a flexible elastomer backbone. Polarization caused by charge displacement along the conjugated backbone is found to induce a large and controlled permittivity enhancement (470 % over the elastomer matrix), while chemical bonding, encapsulates the PANI chains manifesting in hardly any reduction in electric breakdown strength, and hence resulting in a large increase in stored electrostatic energy. This is shown to lead to an improvement in the sensitivity of the measured electromechanical response (83 % reduction of the driving electric field) as well as in the maximum actuation strain (250 %). These results represent a large step forward in the understanding of the strategies which can be employed to obtain high permittivity polymer materials with practical use for electro-elastomer actuation. / Die Palette von elektro-mechanischen Aktuatoren, basierend auf dem Prinzip weicher dehnbarer Kondensatoren, scheint besonders für Anwendungen in der Medizin und für biomimetische Applikationen unbegrenzt. Diese Wandler zeichnen sich sowohl durch hohe Reversibilität bei großer mechanischer Deformation als auch durch ihre Flexibilität aus, wobei die mechanischen Deformationen durch elektrische Felder induziert werden. Die Notwendigkeit von hoher elektrischer Spannung zur Erzeugung dieser mechanischen Deformationen verzögert jedoch die technisch einfache und breite Markteinführung dieser Technologie. Diesem Problem kann durch eine gezielte Materialmodifikation begegnet werden. Eine Modifikation hat das Ziel, die relative Permittivität zu erhöhen, wobei die Flexibilität und die hohe elektrische Durchbruchsfeldstärke beibehalten werden sollten. Durch eine Materialmodifikation kann die Energiedichte des Materials bedeutend erhöht und somit die notwendige Betriebsspannung des Aktuators herabgesetzt werden. Eine Verbesserung der funktionalen Materialeigenschaften kann durch die Verwendung von Nanokompositen erzielt werden, welche die fundamentalen Eigenschaften der Nanopartikel, d.h. ein gutes Verhältnis von Oberfläche zu Volumen nutzen, um eine gezielte makroskopische Materialmodifikation zu bewirken. Diese Arbeit behandelt die Anwendung innovativer Strategien für die Erzeugung von Nanomaterialien mit hoher Permittivität. Die so erzeugten Materialien und deren relevante Aktuatorkenngrößen werden durch elektrische und mechanische Experimente vollständig erfasst. Mittels der klassischen Mischansätze zur Erzeugung von Kompositmaterialen mit hoher Permittivität konnte durch nichtleitendes Titaniumdioxid TiO2 (Rutile) in einem Thermoplastischen-Block-Co-Polymer SEBS (poly-styrene-co-ethylene-cobutylene-co-styrene) die Permittivität bereits um 370 % erhöht und die elektrische Energiedichte um 570 % gesteigert werden. Diese Veränderungen führten jedoch zu einem signifikanten Anstieg der Steifigkeit des Materials. Aufgrund der positiven Rückkopplung von elektrischen und mechanischen Eigenschaften des Kompositmaterials ermöglicht bereits dieser einfache Ansatz eine Verbesserung der Aktuation, bei einer 27 %-igen Reduktion der Aktuatorbetriebsspannung. Eine direkte Verwendung von leitfähigen Nanopartikeln kann ebenso zu einem Anstieg der relativen Permittivität beitragen, wobei jedoch die Leitfähigkeit dieser Nanopartikel bedeutende Wechselwirkungen verursacht, welche somit die Energiedichte des Materials negativ beeinflusst und die praktische Verwendung dieses Kompositsystems ausschließt. Als ein völlig neuer Ansatz zur Steigerung der relativen Permittivität und Energiedichte und abweichend vom klassischen Mischverfahren, wird die Herstellung eines "Molekularen Komposits", basierend auf einem chemischen Propfverfahren, präsentiert. In diesem Ansatz wird ein π-konjugiertes leitfähiges Polymer (PANI) an die Hauptkette des Elastomers der Polymermatrix gebunden. Die daraus resultierende Ladungsverteilung entlang der Elastomerhauptkette bewirkt eine 470 %-ige Steigerung der Permittivität des "Molekularen Komposits" im Vergleich zur Permittivität des unbehandelten Elastomermaterials. Aufgrund der Verkapselung der chemischen Bindungen der PANI-Kette entstehen kaum negative Rückwirkungen auf die elektrischen und mechanischen Eigenschaften des so erzeugten Komposits. Diese Materialeigenschaften resultieren in einem signifikanten Anstieg der Energiedichte des Materials. Das mittels dieses Verfahrens erzeugte Komposit zeigt sowohl eine Steigerung der Sensitivität der elektromechanischen Antwort (Reduktion des elektrischen Felds um 83 %) als auch eine bedeutende Steigerung der maximalen Aktuation (250 %). Die Ergebnisse und Ideen dieser Arbeit stellen einen wesentlichen Sprung im Verständnis zur Permittivitätssteigerung in Polymermaterialien dar und werden deshalb in der Erforschung und Entwicklung von Elastomeraktuatoren Beachtung finden.

Failure of metallic structures operating under shock loading is a common occurrence in engineering applications. It is difficult to estimate the response of complicated systems analytically, due to structure&rsquo / s dynamic characteristics and varying loadings. Therefore, experimental, numerical or a combination of both methods are used for evaluations. The experimental analysis of the shocks due to firing is done for 12.7mm Gatling gun and 25mm cannon. During the tests, the Gatling gun and the cannon are located on military Stabilized Machine Gun Platform and Stabilized Cannon Platform respectively. For the firing tests, ICP (integrated circuit piezoelectric) accelerometers are attached to obtain the loading history for corresponding points. Shock Response Spectrum (SRS) analysis (nCode Glypworks) is done to define the equivalent shock profiles created on test pieces and the mount of 25mm cannon by means of the gun and the cannon firing. Transient shock analysis of the test pieces and the mount are done by applying the obtained shock profiles on the parts in a finite element model (ANSYS). Furthermore, experimental stress analysis due to shock loading is performed for two different types of material and different thicknesses of the test pieces. The input data for the analysis is obtained through measurements from strain rosette precisely located at the critical location of the test pieces. As a result of the thesis, a proposal is tried to be introduced where strain energy density theory is applied to predict the shock failure at military structures.

The work presents investigations into the development of a fuel-powered compact SMA actuator system. For the final SMA actuator, the K-alloy SMA strip (0.9 mm x 2.5 mm), actuated by a forced convection heat transfer mechanism, was embedded in a rectangular channel. In this channel, a rectangular piston, with a slot to accommodate the SMA strip, ran along the strip and was utilized to prevent mixing between the hot and the cold fluid in order to increase the energy density of the system. The fuel, such as propane, was utilized as main energy source in order to achieve high energy and power densities of the SMA actuator system. Numerical analysis was carried out to determine optimal channel geometry and to estimate maximum available force, strain and actuation frequency. Multi-channel combustor/heat exchanger and micro-tube heat exchanger were designed and tested to achieve high heat transfer rate and high compactness. The final SMA actuator system was composed of pumps, valves, bellows, multi-channel combustor/heat exchanger, micro-tube heat exchanger and control unit. The experimental tests of the final system resulted in 250 N force with 2 mm displacement and 1.0 Hz actuation frequency in closed-loop operation, in which the hot and the cold fluid were re-circulated by pumps.

In der vorliegenden Arbeit wird die Darstellung neuer organischer Polyazide dokumentiert, die durch einfache nucleophile Substitution mittels NaN3 dargestellt werden können. Organische Azide mit der Formel RN3 können sich unter Stickstoff-Abspaltung in exothermen, teilweise explosionsartigen Reaktionen zersetzen. Sie sind daher prinzipiell als energiereiche Materialien (HEDM) für entsprechende Anwendungen geeignet. Die als Treibladungsmaterialien potentiell geeignetsten, handhabungssicheren, dendritischen Polyazide werden unter anderem mittels Thermogravimetrie und Differenzkalorimetrie analysiert. In einer neuen Synthesemethode können die wenig bekannten Heteroazidomethane aus Tris(azidomethyl)amin erzeugt werden. Von besonderem Interesse ist dabei die Synthese neuartiger Azidohalogenmethane. Diese können durch analytische Gas-Chromatographie charakterisiert und mittels präparativer Gas-Chromatographie isoliert werden. Durch die 1,3-dipolare Cycloaddition mit Cyclooctin konnten einige Heteroazidomethane zu Triazolen abgefangen und so einer Einkristall-Röntgen-Strukturanalyse zugeführt werden. Als letztes in der homologen Reihe der Azidomethane noch fehlendes Azid konnte Tetraazidomethan synthetisiert werden. Das Perazidomethan besitzt mit 93.3% den für organische Azide höchstmöglichen Stickstoffgehalt. Seine Existenz wurde bislang lediglich durch molekültheoretische Berechnungen nahegelegt. Die Synthese dieses homoleptischen Kohlenstoffazides gelang durch die Behandlung von Trichloracetonitril mit Natriumazid. Es ließ sich durch präparative GC als extrem explosive, farblose Flüssigkeit isolieren. Mit Hilfe der analytischen GC konnten sowohl der Siedepunkt als auch die Polarität von C(N3)4 abgeschätzt werden. C(N3)4 wird desweiteren durch IR, MS, 13C-NMR und 15N-NMR-Spektroskopie sowie durch Einkristall-Röntgen-Strukturanalysen seiner Abfangprodukte mit Cyclooctin charakterisiert. Mit Wasser zeigt C(N3)4 eine quantitative Hydrolyse unter Bildung von Carbonyldiazid. Durch Austauschprozesse mit Na15N3 konnte die mögliche Dissoziation von C(N3)4 nachgewiesen werden. Reaktionen von C(N3)4 mit Phosphinen führen zu Cyanamidderivaten, mit Norbornen sowie Norbornadien wurden über vielstufige Reaktionsmechanismen Aminotetraazole erhalten.

The developments in mobile/portable electronics and alternative energy vehicles prompted engineers and researchers to develop electrochemical energy storage devices called supercapacitors, as the third generation type capacitors. Most of the research and development on supercapacitors focus on electrode materials, electrolytes and hybridization. Some attempts have been directed towards increasing the energy density by employing electroactive materials, such as metal oxides and conducting polymers (CPs). However, the high cost and toxicity of applicable metal oxides and poor long term stability of CPs paved the way to alternative electrode materials. The electroactive materials with carbon particles in composites have been used substantially to improve the stability of supercapacitors. Furthermore, the use of carbon particles and CPs could significantly reduce the cost of supercapacitor electrodes compared to metal oxides. Recent developments in carbon allotropes, such as carbon nanotubes (CNTs) and especially graphene (G), have found applications in supercapacitors because of their enhanced double layer capacitance due to the large surface area, electrochemical stability, and excellent mechanical and thermal properties. The main objective of the research presented in this dissertation is to increase the energy density of supercapacitors by the development of nanocomposite materials composed of graphene and different CPs, such as: (a) polyaniline derivatives (polyaniline (PANI), methoxy (-OCH3) aniline (POA) and methyl (-CH3) aniline (POT), (b) poly(3-4 ethylenedioxythiophene) (PEDOT) and (c) polypyrrole (PPy). The research was carried out in two phases, namely, (i) the development and performance evaluation of G-CP (graphene in conducting polymers) electrodes for supercapacitors, and (ii) the fabrication and testing of the coin cell supercapacitors with G-CP electrodes. In the first phase, the synthesis of different morphological structures of CPs as well as their composites with graphene was carried out, and the synthesized nanostructures were characterized by different physical, chemical and thermal characterization techniques, such as Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), UV-visible spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Raman spectroscopy, BET surface area pore size distribution analysis and Thermogravimetric Analysis (TGA). The electrochemical properties of G-CP nanocomposite-based supercapacitors were investigated using Cyclic Voltammetry (CV), galvanostatic charge-discharge and Electrochemical Impedance Spectroscopy (EIS) techniques in different electrolytes, such as acidic (2M H2SO4 and HCl), organic ( 0.2 M LiClO4) and ionic liquid (1M BMIM-PF6) electrolytes. A comparative study was carried out to investigate the capacitive properties of G-PANI derivatives for supercapacitor applications. The methyl substituted polyaniline with graphene as a nanocomposite (G-POT) exhibited a better capacitance (425 F/g) than the G-PANI or the G-POA nanocomposite due to the electron donating group of G-POT. The relaxation time constants of 0.6, 2.5, and 5s for the G-POT, G-PANI and G-POA nanocomposite-based supercapacitors were calculated from the complex model by using the experimental EIS data. The specific capacitances of two-electrode system supercapacitor cells were estimated as 425, 400, 380, 305 and 267 F/g for G-POT, G-PANI, G-POA, G-PEDOT and G-PPy, respectively. The improvements in specific capacitance were observed due to the increased surface area with mesoporous nanocomposite structures (5~10 nm pore size distribution) and the pseudocapacitance effect due to the redox properties of the CPs. Further, the operating voltage of G-CP supercapacitors was increased to 3.5 V by employing an ionic liquid electrolyte, compared to 1.5 V operating voltage when aqueous electrolytes were used. On top of the gain in the operating voltage, the graphene nano-filler of the nanocomposite prevented the degradation of the CPs in the long term charging and discharging processes. In the second phase, after studying the material's chemistry and capacitive properties in three-electrode and two-electrode configuration-based basic electrochemical test cells, coin cell type supercapacitors were fabricated using G-CP nanocomposite electrodes to validate the tested G-CPs as devices. The fabrication process was optimized for the applied force and the number of spacers in crimping the two electrodes together. The pseudocapacitance and double layer capacitance values were extracted by fitting experimental EIS data to a proposed equivalent circuit, and the pseudocapacitive effect was found to be higher with G-PANI derivative nanocomposites than with the other studied G-CP nanocomposites due to the multiple redox states of G-PANI derivatives. The increased specific capacitance, voltage and small relaxation time constants of the G-CPs paved the way for the fabrication of safe, stable and high energy density supercapacitors.

Behavioral weight loss programs have been shown to be effective for short-term weight loss, however the impact of these programs on dietary changes is unclear. This study examined the changes in participant’s diet and physical activity over the course of a 16-week Internet behavioral weight-loss program. A single-center randomized controlled trial was conducted from August 2008 to December 2008 in Lexington, KY, and sixty-six women whose mean (SD) age was 48.6 (10.8) years and body mass index was 31.8 (3.7) kg/m2 completed all dietary and physical measures. Participants received two face-to-face group sessions with a dietitian, at baseline and 4-weeks, in addition to 16 weekly behavioral weight loss lessons delivered via an Internet website. Participants showed a significant reduction in energy intake (1879.2±771.7 vs. 1372.9±423.7; p<0.001), dietary energy density (2.1±0.5 vs. 1.9±0.5; p=0.002) and a significant increase in diet quality score as measured by the HEI-2005 (53.9±9.9 vs. 57.4±10.6; p =0.002). Participants did not show significant differences in physical activity intensity, duration or energy expenditure. However, post hoc analysis revealed that those who adopted a healthy life style, such as eating more fruits and vegetables and being physically active, achieved greater weight loss than those who did not adopt a healthy lifestyle. Participation in this Internet behavioral weight loss program significantly improved dietary intake in adult women and did not significantly improve daily physical activity levels.