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

Polymeric excipients are generally the least well-characterized components of pharmaceutical formulations. The aim of this dissertation work is to facilitate the quality-by-design (QbD) approach to pharmaceutical formulation and manufacturing by evaluating the inter-grade and inter-batch variability of pharmaceutical-grade polymeric excipients. Sodium alginate, a widely used polymeric excipient, was selected for evaluation using appropriate analytical methods and test conditions, especially rheological methods. The materials used were six different grades of sodium alginate and an additional ten batches of one of the grades. <br>To compare the six grades, steady shear measurements were conducted on solutions at 1, 2, and 3% w/w, consistent with their use as thickening or binding agents. Small amplitude oscillation (SAO) measurements were conducted on sodium alginate solutions at higher concentrations (4-13% w/w) corresponding to their use in controlled release matrices. In order to compare the ten batches of one grade, steady shear and SAO measurements were performed on their solutions at 2% w/w and 8% w/w, respectively. Results show that rheological properties of sodium alginate solutions are influenced by both molecular weight and chemical composition of sodium alginate. ¡§One-point¡¨ apparent viscosity data obtained at one low concentration and one shear rate is not representative of the complex rheological behavior of various grades of sodium alginate solutions at higher concentrations or other shear rates. The potential interchangeability of these different grades used as thickening or binding agents could be established by comparing the apparent viscosities of their solutions as a function of both alginate concentration and shear conditions. For sodium alginate used in controlled release formulations, both steady shear (at one low concentration, e.g., 2% w/w) and SAO measurements (at one high concentration indicative of polymer gel state, e.g., 8% w/w) are recommended to be performed on sodium alginate solutions to ensure interchangeability. Furthermore, among batches of the same grade, significant differences in rheological properties were observed, especially at the high solution concentration (i.e., 8% w/w). In summary, inter-grade and inter-batch variability of sodium alginate can be determined using steady shear and SAO methods. <br>The influence of inter-grade and inter-batch variability of sodium alginate on the functionality of sodium alginate used in matrix tablets was investigated with a focus on compression properties, swelling, erosion behavior of alginate matrix tablets, and drug release from matrix tablets. The compression behavior of four grades and three batches of sodium alginate were studied by compaction energetics, out-of-die Gurnham, and out-of-die Heckel analysis. It was found that sodium alginates deform less plastically than microcrystalline cellulose (MCC PH102) but similar to lactose anhydrous. Sodium alginates also demonstrate more elastic deformations during compression than both MCC PH102 and lactose anhydrous. Compacts prepared from multiple batches of the same grade varied in porosity. The same tensile strength of compacts can be achieved by compressing the multiple batches to the same porosity. <br>Sodium alginate tablets undergo both swelling and erosion in water. Grades with substantially higher apparent viscosities at low solution concentration exhibit a higher percentage of water uptake and a low percentage of erosion. Those batches not significantly different in their apparent viscosities at low solution concentration but significantly different in viscoelasticity at high solution concentrations do demonstrate significant differences in their swelling and erosion behavior. Acetaminophen release from sodium alginate matrix tablets prepared from the four grades and three batches can be well described by a zero-order equation. Significant differences in release profile were observed among various grades and batches. <br>In conclusion, the inter-grade and inter-batch variability of sodium alginate has a significant influence on the swelling, erosion, and drug release behavior of sodium alginate matrix tablets. Apparent viscosities of sodium alginate solution at low concentration alone are not sufficient to predict the functionality of sodium alginate used in matrix tablets. Viscoelastic properties of sodium alginate solutions at high concentrations indicative of polymer gel state are appropriate to be characterized. <br>Further study was conducted to determine whether sodium alginate solutions¡&brkbar; rheological parameters are relevant to sodium alginate¡&brkbar;s use in the formulation of calcium alginate gels. Among the grades with similar guluronic acid percentage (%G), there is a significant correlation between gel fracture force and apparent viscosity. However, the results for the partial correlation analysis for all six grades of sodium alginate show that gel fracture force is significantly correlated with %G, but not with the rheological properties of the sodium alginate solutions. Studies of the ten batches of one grade of sodium alginate show that apparent viscosities of their solutions do not correlate with gel fracture force while tan <em>f</em>Ô values are significantly, but minimally, correlated to gel fracture force. Inter-batch differences in the rheological behavior for one specific grade of sodium alginate are insufficient to predict the corresponding calcium alginate gel's mechanical properties. <br>In summary, rheological methods, including steady shear and small amplitude oscillation, are able to identify the inter-grade and inter-batch variability of sodium alginate. Inter-grade and inter-batch variability of sodium alginate could lead to substantial differences in the functionality of sodium alginate in matrix tablets and in calcium alginate gels. Rheological properties of sodium alginate in solution are suggestive of its functionality as thickeners, or as controlled release agent. However, rheological properties of sodium alginate in solution do not seem to be sufficient to predict the mechanical properties of the corresponding calcium alginate gels. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences / Pharmaceutics / PhD / Dissertation

A global steady increase of energy consumption coupled with the decline of conventional oil resources points to a more aggressive exploitation of heavy oil. Heavy oil is a major source of energy in this century with a worldwide base reserve exceeding 2.5 trillion barrels. Management decisions and production strategies from thermal oil recovery processes are frequently based on reservoir simulation. A proper description of the physical properties, particularly oil viscosity, is essential in performing reliable modeling studies of fluid flow in the reservoir. We simulated cyclic steam injections on the highly viscous Hamaca oil, with a viscosity of over 10,000 cp at ambient temperature, and the production was drastically impacted by up to an order of magnitude when using improper mixing rules to describe the oil viscosity. This thesis demonstrates the importance of these mixing rules and alerts reservoir engineers to the significance of using different options simulators have built in their platforms to describe the viscosity of heavy oils. Log linear and power mixing rules do not provide enough flexibility to describe the viscosity of extra heavy oil with temperature. A recently implemented mixing rule in a commercial simulator has been studied providing satisfactory results. However, the methodology requires substantial interventions, and cannot be automatically updated. We provide guidelines to improve it and suggest more flexible mixing rules that could easily be implemented in commercial simulators. We also provide a methodology to determine the adequate time for each one of the periods in cyclic steam injection: injection, soaking and production. There is a lot of speculation in this matter and one of the objectives of this thesis is to better understand and provide guidelines to optimize oil production using proper lengths in each one of these periods. We have found that the production and injection periods should be similar in time length. Nevertheless, the production period should not be less than the injection period. On the other hand, the soaking period should be as short as possible because it is unproductive time in terms of field oil production for the well and therefore it translates into a negative cash flow for a company.