Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2017-04-19T16:54:59Z No. of bitstreams: 1 2012 - Doralice Chagas Tavares.pdf: 3263200 bytes, checksum: 6f53a1ad9e6222bc2e0b72188b66afd0 (MD5) / Made available in DSpace on 2017-04-19T16:54:59Z (GMT). No. of bitstreams: 1 2012 - Doralice Chagas Tavares.pdf: 3263200 bytes, checksum: 6f53a1ad9e6222bc2e0b72188b66afd0 (MD5) Previous issue date: 2012-08-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The discussion on energy issues are increasingly in evidence. The dynamics of gradual depletion of non-renewable energy reserves such as oil and global warming encourages a race to renewable energy alternatives. This dynamic search economically viable new energy sources through technological progress. In this context, it has increased the development of biodiesel as a renewable energy source. In the case of the Brazilian energy, biodiesel plays a promising role. The country has in its geography major agronomic advantages, being situated in a tropical area, with high brightness and mean annual temperatures. On water availability and regularity of rainfall, becomes the country with the highest potential for renewable energy production. This contributes to the generation of jobs in the primary sector, which in Brazil is of utmost importance to social development and priority of our current government. This ensures the work in the field, reducing the swelling of the big cities and favoring the cycle of self-supporting economy essential to the autonomy of the country. Moreover, the price of diesel fuel in the energy matrix is considerably high compared with other countries. Therefore, biodiesel has a higher potential market in Brazil and the technological innovations associated with it can increase the efficiency of diesel in the consumer sectors, especially the transportation sector. Therefore, this dissertation's main objective is the evaluation of the influence of the major operating variables of the transesterification reaction using as raw material mixtures of jatropha oil, frying oil and beef tallow in different proportions (30/70, 50/50, and 70/30) in the presence of methanol. Moreover, it was studied the technical viability of two different technologies for producing biodiesel (conventional, microwave) and their influence on the reaction conversion. For a better evaluation of the experiments, different schedules were performed, according to the operational variables such as time, molar ratios, temperature, proportion of mixture and catalyst concentration. The best yield value obtained for the production of biodiesel frying / sebum with the conventional technology (BFSC) was 87.09% by weight, 99.20% in content of esters, having a viscosity of 5.42 mm?/s. This performance was achieved using 0.5% KOH, mixtures of 70/30, with time of 3 hours, in terms of molar ratio 9:1 at 70 ?C. In the production of biodiesel frying / sebum with the use of microwaves (BFSM) it was observed that with 1.5% KOH, mixtures of 70/30 at time 10 seconds, the molar ratio of 9:1, was obtained a maximum yield of 88.87% by weight, 99.42% by ester content and a viscosity of biodiesel 5.61 mm?/s. In biodiesel frying / Jatropha using conventional technology (BFPC), it was reached a best yield of 80.42% by weight, 99.99% in amounts of esters, using 0.5% of KOH, mixtures of 70/30, with 3 hours reaction time, molar ratio 9:1, at 70 ?C. The best operational condition for the production of biodiesel from mixture of frying / jatropha with the use of microwaves (BFPM) was observed in 1.5% KOH, with mixtures of 30/70, 10 seconds of time and a molar ratio of 9:1, reaching a total biomass yield, conversion to esters and viscosity of 77.30%, 99.89% and 5.25 mm?/s respectively / A discuss?o em torno das quest?es energ?ticas est? cada vez mais em evid?ncia. A din?mica de esgotamento progressivo de reservas de energias n?o renov?veis como o petr?leo e o aquecimento global incentiva uma corrida por energias renov?veis alternativas. Esta din?mica busca viabilizar economicamente novas fontes energ?ticas por meio do progresso tecnol?gico. ? neste contexto que vem crescendo o desenvolvimento do biodiesel como fonte de energia renov?vel. No caso da matriz energ?tica brasileira, o biodiesel assume um papel promissor. O pa?s tem em sua geografia grandes vantagens agr?colas, por estar situado em uma regi?o tropical, com altas taxas de luminosidade e temperaturas m?dias anuais. Ligado a disponibilidade h?drica e regularidade de chuvas, torna-se o pa?s com maior potencial para produ??o de energia renov?vel. Isso contribui para a gera??o de empregos no setor prim?rio, que no Brasil ? de suma import?ncia para o desenvolvimento social e prioridade de nosso atual governo. Com isso, assegura o trabalho no campo, reduzindo o incha?o das grandes cidades e favorecendo o ciclo da economia auto-sustent?vel essencial para a autonomia do pa?s. Al?m disso, o pre?o do diesel mineral na matriz energ?tica ? consideravelmente elevado se comparado com outros pa?ses. Sendo assim, o biodiesel tem um mercado potencial elevado no Brasil e as inova??es tecnol?gicas a ele associadas podem aumentar a efici?ncia nos setores consumidores de diesel, sobretudo o setor de transportes. Portanto, este trabalho de disserta??o tem como principais objetivos a avalia??o da influ?ncia das principais vari?veis de opera??o da rea??o de transesterifica??o usando como mat?ria-prima a mistura dos ?leos de pinh?o manso, de fritura e sebo bovino, em diferentes propor??es (30/70, 50/50, e 70/30), na presen?a de metanol, na convers?o reacional e a avalia??o da influ?ncia de duas tecnologias de produ??o de biodiesel (convencional e microondas) na convers?o da rea??o. Para uma melhor avalia??o dos experimentos, foram realizados diferentes planejamentos de experimentos, de acordo com as vari?veis de opera??o como tempo, raz?o molar, temperatura, propor??o da mistura e concentra??o de catalisador. O melhor valor de rendimento obtido para a produ??o do biodiesel de fritura/sebo com a tecnologia convencional (BFSC) foi de 87,09% em massa, 99,20% em teor de ?steres com uma viscosidade de 5,42 mm?/s. Esse rendimento foi alcan?ado usando 0,5% de KOH, nas misturas de 70/30, com tempo de 3 horas, raz?o molar em condi??es de 9:1, a 70 ?C. Na produ??o do biodiesel de fritura/sebo com o uso das microondas (BFSM) observou-se que com 1,5% de KOH, nas misturas de 70/30, com tempo 10 segundos, raz?o molar de 9:1, foi obtido um rendimento m?ximo de 88,87% em massa, 99,42 % em teor de ?steres e um biodiesel com viscosidade de 5,61 mm?/s. No biodiesel de fritura/pinh?o manso utilizando a tecnologia convencional (BFPC) obteve-se o melhor rendimento em massa de 80,42%, em teores de ?steres de 99,99% usando 0,5% de KOH, nas misturas de 70/30, com tempo reacional de 3 horas, raz?o molar 9:1 a 70 ?C. A melhor condi??o operacional para a produ??o de biodiesel de fritura/pinh?o manso com o uso das microondas (BFPM) foi observado em: 1,5% de KOH, nas misturas de 30/70, com tempo de 10 segundos e raz?o molar de 9:1, com rendimento em massa, convers?o em ?steres e viscosidade de 77,30%, 99,89% e 5,25 mm?/s, respectivamente

Made available in DSpace on 2017-07-10T15:14:46Z (GMT). No. of bitstreams: 1 Willian Wazilewski.pdf: 3585508 bytes, checksum: 5c100553aa68a7f4273707361803185a (MD5) Previous issue date: 2012-02-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Biodiesel quality is critical to the successful commercialization of this fuel, so the product must meet some worldwide established parameters to guarantee their full environment roll functionality. Within these parameters there is the kinematic viscosity which may be affected due the degradation of the biofuel, such degradation occurs due atmospheric disturbances which all forms of organic matter are exposed to, and this degradation is accentuated when exposed to high temperatures or in contact with a catalyst matter. As a result of this, a factor that relates the degrees of resistance of a product to different oxidizing agents were created called as oxidation stability. This work aimed to study the oxidative stability of biodiesel produced from vegetable oil of soy and crambe. For this study the techniques of infrared spectroscopy, refractive index at 40 ° C and kinematic viscosity at 40 ° C were used to monitor the level of oxidation of the biodiesel. Viscometric studies revealed that biodiesel of crambe is more stable than soybean when they were exposed to thermal stress in an incubator at 130 ° C, with the addition of 5 and 10% of crambe biodiesel it reduces the viscosimetric change about 43,9% compared to pure soybean biodiesel. Looking at the index of refraction were found that the variation, in the case of pure soybean biodiesel, was about 0.0042 and its blends were 0.0028, 0.0025 and 0.0022 for 5, 10 and 20% of crambe biodiesel, respectively, compared to pure soybean biodiesel would be a stabilization of 33.3, 41.4 and 47.6% for the blends with 5, 10 and 20% of crambe biodiesel, respectively. By infrared spectroscopy it is clear that there was a formation of carbonyl grouping more intense in the soybean biodiesel compared to crambe biodiesel subjected to thermal stress for the same period. / A qualidade do biodiesel é de suma importância para o sucesso da comercialização deste combustível, sendo assim, o produto deve atender a parâmetros estabelecidos mundialmente, para que seja garantida sua total funcionalidade ambiental. Dentro destes parâmetros tem-se a viscosidade cinemática a qual pode ser afetada em virtude da degradação do biocombustível. Tal degradação ocorre devido às intempéries atmosféricas a qual estão expostos todas as formas de matéria orgânica, sendo esta degradação acentuada quando da exposição a temperaturas elevadas ou em contato com agentes catalisadores. Em virtude disto denominou-se a estabilidade à oxidação como sendo um fator que relaciona o grau de resistência do produto aos diferentes agentes oxidantes. O presente trabalho teve como objetivo o estudo da estabilidade oxidativa do biodiesel produzido a partir do óleo vegetal de crambe e soja. Utilizou-se para este estudo as técnicas de espectroscopia no infravermelho, índice de refração a 40ºC e viscosidade cinemática a 40ºC para acompanhar o nível de oxidação dos biodieseis. Os estudos viscosimétricos revelaram que o biodiesel de crambe é mais estável que o de soja quando da exposição destes ao stress térmico em estufa a 130ºC, sendo que a adição de 5 e 10% de biodiesel de crambe reduz a alteração viscosimétrica em cerca de 43,9% em relação ao biodiesel de soja puro. Observando o índice de refração constatou-se que a alteração deste, no caso do biodiesel de soja, foi de 0,0042 e para suas blendas foram 0,0028, 0,0025 e 0,0022 para 5, 10 e 20% de biodiesel de crambe, respectivamente. Em relação ao biodiesel de soja seria uma estabilização de 33,3, 41,4 e 47,6%, para as blendas com 5, 10 e 20 % de biodiesel de crambe, respectivamente. Pela espectroscopia no infravermelho percebe-se que houve uma formação de grupamento carbonila mais intensa no biodiesel de soja quando comparado com o biodiesel de crambe submetido ao stress térmico pelo mesmo período de tempo.

Uma reação relativamente simples vem auxiliando cada vez mais uma variedade de aplicações analíticas na determinação de diversos compostos. A reação peroxioxalato, que produz o fenômeno de quimiluminescência, pode identificar compostos como peróxido de hidrogênio e compostos orgânicos fluorescentes presentes em diferentes meios. O estudo dessa reação em líquidos iônicos utilizados como solvente se torna cada vez mais interessante, por se tratar de solventes verdes, beneficiando assim o meio ambiente. Neste projeto, foi estudado a reação de oxalato de bis(2,4,6-triclorofenila) (TCPO) com peróxido de hidrogênio, em 1,2-dimetoxietano (DME), carbonato de propileno (CP) e misturas binárias de líquido iônico e DME, catalisada por imidazol. Dois líquidos iônicos (LIs) foram utilizados, sendo eles o tetrafluoroborato de 1-butil-3-metilimidazólio (BuMeImBF4) e o tetrafluoroborato de 1-decil-3-metilimidazólio (DecMeImBF4). As misturas binárias foram preparadas com até 50% de sua composição constituída de LI, definindo assim diferentes condições experimentais no estudo da reação, podendo ser aproveitado em futuras aplicações analíticas. Estudos cinéticos mostraram que o imidazol age não somente como catalisador básico mas também nucleofílico, tanto nos solventes orgânicos puros quanto nos meios contendo LI. Nos solventes puros e nas misturas binárias destes com líquidos iónicos determinaram-se os valores das constantes de velocidade observadas (kobs) e os rendimentos quânticos singlete (ΦS). Os valores de kobs se tornam maiores nas misturas contendo LI em sua composição, entretanto, os valores de ΦS não sofrem alteração significativa, mostrando uma leve tendência de diminuição. A determinação dos parâmetros de polaridade e viscosidade das misturas binárias DME/LI mostra que ambos aumentam com o aumento da concentração do LI. A baixa sensibilidade dos rendimentos quânticos à composição dos meios DME/LI pode ser entendida por um efeito de composição da viscosidade e polaridade do meio. Enquanto o aumento da viscosidade deve aumentar a eficiência de quimiexcitação, o aumento da polaridade pode levar à diminuição do rendimento devido a separação dos íons radicais envolvidos no passo de quimiexcitação ocorrendo pelo mecanismo CIEEL (Chemically Initiated Electron Exchange Luminescence). De acordo com os estudos realizados, foi demonstrado que a reação peroxioxalato pode ser conduzida em meios contendo líquidos iônicos, favorecendo assim uma maior utilização destes solventes verdes. / A relatively simple chemical reaction has increasingly shown utility in a variety of analytical applications for the determination of various compounds. The peroxyoxalate reaction, which produces the chemiluminescence phenomenon, can be used to identify and quantify several compounds, such as hydrogen peroxide and fluorescent organic compounds in different reaction media. The study of this reaction in media containing ionic liquids is of increasing interest, because of its possible utilization as \"green\", environmental compatible, solvents in analytical assays. In this project, the kinetics of the imidazole catalyzed reaction of bis(2,4,6- trichlorophenyl) oxalate (TCPO) with hydrogen peroxide in 1,2-dimethoxyethane (DME), propylene carbonate (CP) and binary mixtures of ionic liquids and DME, is studied, using the two ionic liquids (LIs) 1-butyl-3-methylimidazolium tetrafluoroborate (BuMeImBF4) and 1- decyl-3-methylimidazolium tetrafluoroborate (DecMeImBF4). The binary mixtures were prepared with up to 50% of their composition consisting of LI, thus, defining different experimental conditions in the study of the reaction, which could be used in future analytical applications. Kinetic studies show that imidazole acts not only as base, but also studied as nucleophilic catalyst, in molecular solvents as well as in LI-containing media. In the binary mixtures studied, the values of the observed rate constants (kobs) and singlet quantum yields (ΦS) were determined. The kobs values are higher in mixtures containing LIs in their composition, however, ΦS values do not change significantly, showing only a slight tendency to decrease. The determination of the polarity and viscosity parameters of the binary DME / LI mixtures shows that both increase with increasing LI concentration. The low sensitivity of quantum yields to the composition of the DME / LI media can be understood by a combined medium effect of the viscosity and polarity. While increased viscosity should increase the efficiency of chemiexcitation, increased polarity may lead to decreased quantum yields due to separation of the radical ions involved in the chemiexcitation step occurring by the Chemically Initiated Electron Exchange Luminescence (CIEEL) mechanism. According to the studies, it has been demonstrated that the peroxyoxalate reaction can be conducted in media containing ionic liquids, indicating that analyical assays with the peroxyoxalate reaction migt be performed in these \"green\" solvents.

A dusty plasma is a mixture of electrons, ions, neutral gas atoms, and small particles of solid matter (dust). In a dusty plasma produced in the laboratory, dust particles gain a large electric charge from the other charged species, so that their interparticle interactions can be very strong. Frequently, the average interparticle potential energy is higher than the thermal kinetic energy of the dust particles, and in this case, they constitute a strongly coupled plasma. As with all strongly coupled plasmas, the dust particles can behave like typical solids or liquids. In this thesis, I report the results of dusty plasma experiments that are focused on the behavior of liquids. I use a so-called two-dimensional (2D) dusty plasma that consists of only a single horizontal layer of dust particles. Tracking each particle with video microscopy and image analysis methods allows the calculation of important liquid properties, like the viscosity coefficient. In Chapter 2, I describe an improved laser heating method for producing liquid-like conditions in a 2D dusty plasma. Two laser beams are scanned across the dust layer in a new pattern to increase the kinetic energy of the particles and melt the ground state crystalline lattice. The new scanning pattern improves the randomness of the resulting particle motion so that it more closely resembles that of a liquid in a thermal equilibrium. In Chapter 3, I report a viscosity measurement in a dusty plasma that is unaffected by the complicating effects of temperature nonuniformities and shear thinning. This measurement is enabled by an addition to my experimental apparatus that I also detail here. I find the viscosity to be significantly higher than in previous measurements, which I attribute to the avoidance of shear thinning. In Chapter 4, I present measurements of viscosity using the Green-Kubo method, and compare the results to those of my previous measurement. I find that the two methods yield viscosity values that differ by about 60%, over the entire temperature range attained in the experiment. Possible sources of this difference are evaluated. Finally, in Chapter 5, I report the first experimental confirmation of a theoretical expression describing the decay of time autocorrelation functions. This theoretical expression fits experimentally calculated autocorrelation functions within error bars, especially at short times when a simple exponential decay fails. I also propose an intuitive description wherein an observed transition in the autocorrelation function is due to the onset of collisional scattering.

The hematological and rheological characteristics of blood from a number of vertebrates was compared to assess possible species differences in blood viscosity that may influence cardiovascular oxygen transport. Nucleated red blood cells (RBCs) were more viscous (measured by cone-plate viscometry) in comparison with enucleate (mammalian) RBCs at hematocrits greater than 40% when measured at equivalent temperatures. The lower viscosity of enucleate RBCs is attributed to an enhanced deformability of enucleate cells in comparison to nucleated cells.

In this thesis, we examine key geometric properties of a class of Carnot groups of Heisenberg type. After first computing the geodesics, we consider some partial differential equations in such groups and discuss viscosity solutions to these equations.

Polycarbonate polyurethane (PCPU) has been studied as a novel polymer impregnated with nanoparticles for improved mechanical, thermal and adhesion properties [4]. This study investigates the synthesis of polycarbonate polyurethane (PCPU) polymeric nanofiber membranes by the process of electrospinning. This study further examines all the parameters associated with electrospinning a novel PCPU polymeric solution impregnated with nanofillers, such as nanoparticles, to produce fiber membranes. Tetrahydrofuran (THF) and N, N dimethylformamide (DMF) are used as solvents to dissolve PCPU polymer. One percent (1%) of nanofillers like silver and silica nanoparticles are added to PCPU polymer solution to investigate the impact on polymer solution properties, which in turn affects the fiber formation. Process parameters are studied by evaluating the impact each parameter has on the fiber formation. PCPU polymer concentrations of three polymer solutions (PCPU, PCPU + 1% silver and PCPU + 1% silica) with the appropriate solvent mixture ratio are achieved to produce polymeric fiber membranes with minimal bead formation. Polymeric nanofiber membranes of PCPU, PCPU + 1% silver and PCPU + 1% silica are produced using THF/DMF: 70/30 (V/V) solvent mixture. The polymeric nanofiber membranes obtained are characterized by using a scanning electron microscopy, rotational viscometer, tensiometer, contact angle measurement device, fourier transform infrared spectroscopy (FTIR). A comparative life cycle assessment (LCA) is performed to evaluate environmental impacts associated with solvents in the process of producing PCPU polymeric nanofiber membranes. The LCA is completed to gauge the potential impacts PCPU nanofiber membranes may have when utilized for various applications. This study discusses the successful production and characterization of good quality (no beading) polymeric nanofiber membranes of PCPU and novel composites of PCPU + 1% silver and PCPU + 1% silica. This two dimensional production of impregnated PCPU in nanofiber form will give researchers the opportunity to capitalize on the large surface areas of PCPU nanofibers versus PCPU thin films.

Abstract This thesis examines magnetic reconnection in the solar corona. Magnetic reconnection is the only mechanism which allows the magnetic topology of magnetized plasmas to be changed. Many of the dynamic processes in the Sun's atmosphere are believed to be driven by magnetic reconnection and studying the behaviour of such phenomena is a key step to understanding the reconnection mechanism. In Chapters 1 to 3, we discuss the physical and mathematical framework on which current magnetohydrodynamic reconnection models are based. The aim of the thesis is to investigate theoretical models of magnetic reconnection using variety of analytic and numerical techniques within the theoretical frame work of magnetohydrodynamics (MHD). In Chapter 4 we use a line-tied X-point collapse model for compressible plasmas to investigate the role of viscosity on the energy release mechanism. This model also provides the basis for the investigation of Chapter 5 which explores the impact of Hall currents in the transient X-point energy dissipation. Chapter 6 is concerned with how reconnection is modified in the presence of generalized Ohm's law which includes both Hall current and electron inertia contributions. In contrast to the closed X-point collapse geometry adopted for compressible plasmas previously, we find it more convenient to explore this problem using an open incompressible geometry in which plasma is continually entering and exiting the reconnection region. Specially, we find the scaling of the Hall-MHD system size analytically, rather than numerically as in the X-point problem of Chapter 5. Chapter 7 summarizes the results of investigations in Chapters 4, 5 and 6.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 145-151).

-Glucan is a soluble fibre shown to help regulate blood sugar and lower cholesterol. Incorporation into food, particularly bread, may affect -glucans physicochemical properties and health benefits. The journey of -glucan through the mixing, fermenting, baking, and storage of bread was evaluated, in terms of its solubility and viscosity under in vitro physiological conditions, at levels most likely to be presented to consumers (0.75, 1.0, 1.5 g -glucan/serving). Satiety and glycemic response measures, in addition to the quality and consumer acceptability of the bread, were also investigated. In dough, viscosity of the physiological extract was impacted by -glucan level, fermentation time, and endogenous flour enzymes. Fermentation decreased -glucan solubility indicating that the reduction in viscosity depends on both molecular degradation and solubility reduction. Dough rheological properties and microstructure, characterized using an oscillatory rheometer and fluorescence microscopy, respectively, showed that -glucan may interfere with the gluten network, though gluten addition may help improve this. The breads physical properties supported these observations, as -glucan decreased loaf volume and height, while gluten addition corrected this. Baking increased -glucan solubilization to 58-60%, compared to 9% in dough. Gluten addition increased solubility further (67-68%). Similar trends were seen for extract viscosity and were supported by fluorescence microscopy images. Storage at ambient, refrigeration and frozen conditions showed that bread with -glucan should be consumed fresh to maintain highest bread quality and -glucan solubility and viscosity. Bread with -glucan kept panelists full, longer. Reducing sugar release values implied that satiety may depend on digesta viscosity and/or rate of sugar release from the bread. Bread with -glucan produced the most leveled glucose curve; though areas under the 2 hr plasma glucose curves were similar. Consumers liked the 0.75 g -glucan/serving bread and the control more than the 1.5 g -glucan/serving bread, though provision of health information improved bread liking to similar values. The findings demonstrate that low solubility -glucan concentrate that gets solubilized upon baking is well suited for bakery applications and that a successful -glucan-fortified bread product is possible. Commercialization of bread fortified with -glucan would provide consumers an additional source of dietary fibre to assist them in coming closer to recommended daily intakes. / Food Science and Technology