Nas últimas décadas, o interesse nas propriedades específcas dos organolantanídeos está aumentando muito, principalmente no uso como catalisadores em diversas reações orgânicas. Com o objetivo de contribuir para a aplicação de compostos organolantanídeos como catalisadores nessas reações, avaliou-se o desempenho de sistemas catalíticos a base de compostos organolantanídeos do tipo LnBrCp2(THF)2 e LnBrCp*2THF (Cp = ciclopentadienil , Cp* = pentametilciclopentadienil Ln = Pr e Yb) utilizando metilaluminoxano (MAO) como cocatalisador em reações de polimerização de etileno, propileno, metil metacrilato e estireno. Os compostos foram sintetizados pela reação entre os brometos de lantanídeos anidros e NaCp ou NaCp* em THF, na proporção molar 1:2,2 (Ln:Cp,Cp*) e caracterizados pela %Ln e %Br, termogravimetria, espectroscopia vibracional no infravermelho e RMN de 1H. Os sistemas estudados não foram ativos nas reações de polimerização de etileno, propileno ou metil metacrilato, mas produziram poliestireno com rendimento de até 8,0 % em 1,5 h na presença de tolueno e até 26,0 % em 1,5 h com PrBrCp*2THF/MAO a 90º C na ausência de solvente. Os polímeros formados são atáticos, indicando que a polimerização não é estereoespecífica, e possuem baixas massas molares. / In the last decades, the specific properties of organolanthanide compounds have attracted attention, specially in applications as catalysts in organic reactions. In an attempt to contribute to the application of these compounds in olefin polymerization reactions, we studied the catalytic systems based on LnBrCp2(THF)2 and LnBrCp*2THF (Cp = cyclopentadienyl , Cp* = pentamethylciclopentadienyl, Ln = Pr, Yb) and methylaluminoxane (MAO) as cocatalyst in polymerization of ethylene, propylene, methyl methacrylate and styrene. The organolanthanide compounds were obtained by the reaction of anydrous lanthanide tribromides and NaCp or NaCp* in THF, in the molar proportion of 1:2,2 (Ln:Cp, Cp*) and were characterized by %Ln, %Br, thermogravimetry, vibrational spectroscopy in the infrared region and 1H NMR. The catalytic systems were not active in ethylene, propylene, methyl methacrylate polymerizations, but were able to form polystyrene with yields up to 8.0 % in 1.5 h in toluene and 26% in 1.5 h in absence of solvent, using PrBrCp*2THF/MAO at 90º C. The polymers obtained are atactic, indicating no stereospecificity of the catalytic system, and have low molar masses.

O propósito desta Tese é realizar o estudo da implementação do controle avançado do tipo controle preditivo baseado em modelo (MPC) e otimização em tempo real (RTO) em uma unidade de processo industrial usando como ferramentas softwares comerciais de simulação e otimização de processos. As soluções propostas podem ser consideradas como estratégias de integração entre RTO e MPC de uma e duas camadas. Na estratégia de duas camadas, a camada superior que considera um modelo rigoroso não linear do processo computa e envia targets otimizantes à camada dinâmica do MPC, que computa as ações de controle necessárias para alcançar esses targets e estabilizar o processo. Na estratégia de uma camada, mais conhecida como MPC econômico, temos a inclusão do gradiente da função econômica na função custo do controlador preditivo. Ambas as estratégias foram estudadas e suas implementações na coluna de destilação de propeno/propano com integração energética da unidade de produção de propeno da refinaria de Capuava da Petrobras foram simuladas. Este estudo foi realizado em varias etapas. Primeiro, uma simulação dinâmica do processo foi realizada usando o simulador dinâmico SimSci Dynsim® para ser usada como uma planta virtual que também foi usada para a identificação dos modelos usados nos controladores preditivos. Segundo, os algoritmos de controle avançado foram desenvolvidos em Matlab® baseados no controlador preditivo de horizonte infinito (IHMPC), no controlador preditivo robusto (RIHMPC) e no MPC econômico. Terceiro, o algoritmo de RTO foi desenvolvido no pacote de otimização em tempo real Simsci ROMeo®, onde o modelo rigoroso não linear do processo foi implantado incluindo as etapas de simulação, reconciliação de dados e otimização. Quarto, modificações e adaptações dos algoritmos e rotinas desenvolvidas foram feitas para permitir a comunicação de dados em tempo real usando o protocolo de transferência de dados OPC entre Matlab®, Simsci Dynsim® e Simsci ROMeo ®. Finalmente, foram desenvolvidos o sequenciamento e automação dos algoritmos tanto para leitura e escritura de dados, assim como, para a rotina do RTO. Para todas as estratégias propostas nesta Tese, foram incluídos exemplos de simulação representativos onde se pode evidenciar a estabilidade e convergência das estratégias propostas, chegando-se à conclusão que as estruturas propostas de RTO/MPC podem ser implementadas no sistema real. / The aim of this Thesis is to study the implementation of advanced control, specifically, Model Predictive Control (MPC) and real time optimization (RTO) in an industrial process system using tools such as commercial software for process simulation and optimization. The proposed solutions can be considered as integration strategies of RTO and MPC with one and two layers. In the two layer approach, the upper layer that considers a rigorous non-linear steady-state model of the process computes optimizing targets that are sent to the dynamic layer that are based on the MPC, which computes the necessary control actions to reach those targets and stabilize the process system. In the one layer strategy, also called as Economic MPC, the gradient of the economic function is included in the cost function of the predictive controller. Both strategies were studied and their implementation in the energy-recovery propylene/propane splitter system of the propylene production unit at the Capuava Refinery of Petrobras was simulated. In order to accomplish this objective, the work was developed in several steps. Firstly, a dynamic simulation of the process was built in the dynamic simulator Simsci Dynsim® so that it could be used as a virtual plant in which the model identification could also be performed. Secondly, the advanced control algorithms were developed in Matlab® based on the Infinite Horizon Model Predictive Control (IHMPC), the robust predictive controller (RIHMPC) and the Economic MPC. Thirdly, the RTO algorithm was developed in the real-time optimization package Simsci ROMeo®, where the non-linear rigorous model of the process was built including the stages of simulation, data reconciliation and optimization. Fourthly, modifications and adaptation of the developed algorithms and routines were included to allow the real-time data communication considering the OPC data transfer protocol between Matlab®, Dynsim® and ROMeo ®. Finally, a sequence of algorithms was developed and automated for data reading and writing, as well as, for the RTO sequence. For all the strategies developed in this Thesis, representative simulation examples were presented in order to show the closed-loop stability and convergence of the proposed approaches, leading to the conclusion that the proposed RTO/MPC structures can be implemented in the real system.

Nas últimas décadas, o interesse nas propriedades específcas dos organolantanídeos está aumentando muito, principalmente no uso como catalisadores em diversas reações orgânicas. Com o objetivo de contribuir para a aplicação de compostos organolantanídeos como catalisadores nessas reações, avaliou-se o desempenho de sistemas catalíticos a base de compostos organolantanídeos do tipo LnBrCp2(THF)2 e LnBrCp*2THF (Cp = ciclopentadienil , Cp* = pentametilciclopentadienil Ln = Pr e Yb) utilizando metilaluminoxano (MAO) como cocatalisador em reações de polimerização de etileno, propileno, metil metacrilato e estireno. Os compostos foram sintetizados pela reação entre os brometos de lantanídeos anidros e NaCp ou NaCp* em THF, na proporção molar 1:2,2 (Ln:Cp,Cp*) e caracterizados pela %Ln e %Br, termogravimetria, espectroscopia vibracional no infravermelho e RMN de 1H. Os sistemas estudados não foram ativos nas reações de polimerização de etileno, propileno ou metil metacrilato, mas produziram poliestireno com rendimento de até 8,0 % em 1,5 h na presença de tolueno e até 26,0 % em 1,5 h com PrBrCp*2THF/MAO a 90º C na ausência de solvente. Os polímeros formados são atáticos, indicando que a polimerização não é estereoespecífica, e possuem baixas massas molares. / In the last decades, the specific properties of organolanthanide compounds have attracted attention, specially in applications as catalysts in organic reactions. In an attempt to contribute to the application of these compounds in olefin polymerization reactions, we studied the catalytic systems based on LnBrCp2(THF)2 and LnBrCp*2THF (Cp = cyclopentadienyl , Cp* = pentamethylciclopentadienyl, Ln = Pr, Yb) and methylaluminoxane (MAO) as cocatalyst in polymerization of ethylene, propylene, methyl methacrylate and styrene. The organolanthanide compounds were obtained by the reaction of anydrous lanthanide tribromides and NaCp or NaCp* in THF, in the molar proportion of 1:2,2 (Ln:Cp, Cp*) and were characterized by %Ln, %Br, thermogravimetry, vibrational spectroscopy in the infrared region and 1H NMR. The catalytic systems were not active in ethylene, propylene, methyl methacrylate polymerizations, but were able to form polystyrene with yields up to 8.0 % in 1.5 h in toluene and 26% in 1.5 h in absence of solvent, using PrBrCp*2THF/MAO at 90º C. The polymers obtained are atactic, indicating no stereospecificity of the catalytic system, and have low molar masses.

Electronic cigarettes (ECIGs) are a class of tobacco products that use a heating element to aerosolize a liquid, typically containing nicotine, allowing for user inhalation. Despite their rapid growth in popularity, little is known about ECIGs including how certain device and liquid factors influence nicotine delivery, user physiological and subjective responses, and puffing behavior (puff topography). Limited pre-clinical research has demonstrated that the ratio of two solvents commonly found in ECIG liquids, propylene glycol (PG) and vegetable glycerin (VG), may have an influence on the nicotine content of ECIG aerosols. However, the extent to which PG:VG ratio in ECIG liquids influences acute effects experienced by ECIG users is unknown. The primary purpose of this clinical laboratory study was to examine the influence of PG:VG ratio on plasma nicotine concentration, heart rate (HR), subjective effects, and puff topography in experienced ECIG users. Thirty ECIG-experienced individuals participated in four independent laboratory conditions that differed only by the PG:VG ratio in the ECIG liquid (100:0, 55:45, 20:80, and 2:98). In each condition, participants used a 3.3 volt “eGo” ECIG battery attached to a 1.5 Ohm dual coil “cartomizer” loaded with 1 ml of ECIG liquid (nicotine concentration: 18 mg/ml). Participants completed two ECIG use bouts (10 puffs with 30 sec inter-puff-interval) in each study condition. ECIG PG:VG ratio had a direct influence on nicotine delivery, subjective effects, and puff topography. Nicotine delivery and overall nicotine intake were highest following the use of the liquids containing mostly PG, despite participants taking significantly shorter and smaller puffs in these conditions, suggesting PG may be a more efficient nicotine-delivery vehicle than VG. Abstinence symptoms were suppressed similarly across all PG:VG ratios, and HR also increased in a similar fashion in all conditions following ECIG use. Participants reported significantly lower scores on items assessing sensory ECIG effects following use of the 100PG:0VG liquid, indicating a lower overall satisfaction with this liquid. Further evaluating the influence of PG and VG and other ECIG device and liquid characteristics on ECIG acute effects using clinical laboratory methodologies could inform regulations of these products.

<p>In this thesis, I present the electrochemical studies of three dendrimeric polypropylene imine (PPI) nanomaterials and their applications as a platform in the development of a novel label free DNA nanobiosensor based on electrochemical impedance spectroscopy. Cyclic voltammetry (CV), differentia pulse voltammetry (DPV), square wave voltammetry (SWV) and electrochemical impedance spectroscopy (EIS) techniques were used to study and model the electrochemical reactivities of the nanomaterials on glassy carbon electrode (GCE) as the working electrode.</p>

Throughout this thesis work, various catalysts were investigated with combinational approach to develop highly active and selective novel catalysts for direct epoxidation of propylene to PO using molecular oxygen. The promoted and un-promoted silver (Ag), copper (Cu), ruthenium (Ru), manganese (Mn) mono and multimetallic catalytic systems over different silica supports were prepared via sol-gel method and incipient wetness method. In addition to support effect, the effects of different promoters on the catalytic performances of these catalyst candidates were investigated. The study showed that commercial silica (c-SiO2) is the most effective support when compared to silica (SiO2) and silica synthesized with templete (t-SiO2). Among bimetallic catalytic systems containing Ag, Ru, Mn and Cu metals, c-SiO2 supported Cu-Ru catalyst was determined as the most active catalytic system. In addition, the most effective v catalyst and promoter in the epoxidation reaction was determined as NaCI promoted Cu-Ru catalyst supported over c-SiO2 with 35.98% selectivity&amp / 9.55% conversion (3.44% yield) at 3000C and 0.5 feed gas ratio (C3H6/O2).. In the study, the selected catalysts showed low and high PO productivity were also investigated by characterization techniques such as XRD, XPS, BET and FTIR.It was inferred from characterization tests that bimetallic systems reveal a synergistic behavior by exposing more active sites on the silica support material with respect to their monometallic counterparts. Besides, NaCl catalytic promoter has a strong interaction particularly with the Cu sites on the Cu/Ru/SiO2 catalyst surface, altering the electronic structure of Cu sites that favors to PO production.

This study deals with poly(ether block amide) (PEBA) (type 2533) membranes for gas separation. A new method was developed to prepare flat thin film PEBA membranes by spontaneous spreading of a solution of the block copolymer on water surface. The membrane formation is featured with simultaneous solvent evaporation and solvent exchange with the support liquid, i.e. water. The formation of a uniform and defect-free membrane was affected by the solvent system, polymer concentration in the casting solution and temperature. Propylene separation from nitrogen, which is relevant to the recovery of propylene from the de-gassing off-gas during polypropylene manufacturing, was carried out using flat PEBA composite membranes formed by laminating the aforementioned PEBA on a microporous substrate. The propylene permeance was affected by the presence of nitrogen, and vice versa, due to interactions between the permeating components. Semi-empirical correlations were developed to relate the permeance of a component in the mixture to the pressures and compositions of the gas on both sides of the membrane, and the separation performance at different operating conditions was analyzed in terms of product purity, recovery and productivity on the basis of a cross flow model. To further understand gas permeation behavior and transport mechanism in the membranes, sorption, diffusion, and permeation of three olefins (i.e., C2H4, C3H6, and C4H8) in dense PEBA membranes were investigated. The relative contribution of solubility and diffusivity to the preferential permeability of olefins over nitrogen was elucidated. It was revealed that the favorable olefin/nitrogen permselectivity was primarily attributed to the solubility selectivity, whereas the diffusivity selectivity may affect the permselectivity negatively or positively, depending on the operating temperature and pressure. At a given temperature, the pressure dependence of solubility and permeability could be described empirically by an exponential function. The limiting solubility at infinite dilution was correlated with the reduced temperature of the permeant. The separation of volatile organic compounds (VOCs), which are more condensable than olefin gases, from nitrogen stream by the thin film PEBA composite membranes for potential use in gasoline or other organic vapour emission control was also studied. The membranes exhibited good separation performance for both binary VOC/N2 and multi-component VOCs/N2 gas mixtures. The permeance of N2 in the VOC/N2 mixtures was shown to be higher than pure N2 permeance due to membrane swelling induced by the VOCs dissolved in the membrane. The effects of feed VOC concentration, temperature, stage cut, and permeate pressure on the separation performance were investigated. Additionally, hollow fiber PEBA/polysulfone composite membranes were prepared by the dip coating technique. The effects of parameters involved in the procedure of polysulfone hollow fiber spinning and PEBA layer deposition on the permselectivity of the resulting composite membranes were investigated. Lab scale PEBA hollow fiber membrane modules were assembled and tested for CO2/N2 separation with various flow configurations using a simulated flue gas (15.3% carbon dioxide, balance N2) as the feed. The shell side feed with counter-current flow was shown to perform better than other configurations over a wide range of stage cuts in terms of product purity, recovery and productivity.

This study deals with poly(ether block amide) (PEBA) (type 2533) membranes for gas separation. A new method was developed to prepare flat thin film PEBA membranes by spontaneous spreading of a solution of the block copolymer on water surface. The membrane formation is featured with simultaneous solvent evaporation and solvent exchange with the support liquid, i.e. water. The formation of a uniform and defect-free membrane was affected by the solvent system, polymer concentration in the casting solution and temperature. Propylene separation from nitrogen, which is relevant to the recovery of propylene from the de-gassing off-gas during polypropylene manufacturing, was carried out using flat PEBA composite membranes formed by laminating the aforementioned PEBA on a microporous substrate. The propylene permeance was affected by the presence of nitrogen, and vice versa, due to interactions between the permeating components. Semi-empirical correlations were developed to relate the permeance of a component in the mixture to the pressures and compositions of the gas on both sides of the membrane, and the separation performance at different operating conditions was analyzed in terms of product purity, recovery and productivity on the basis of a cross flow model. To further understand gas permeation behavior and transport mechanism in the membranes, sorption, diffusion, and permeation of three olefins (i.e., C2H4, C3H6, and C4H8) in dense PEBA membranes were investigated. The relative contribution of solubility and diffusivity to the preferential permeability of olefins over nitrogen was elucidated. It was revealed that the favorable olefin/nitrogen permselectivity was primarily attributed to the solubility selectivity, whereas the diffusivity selectivity may affect the permselectivity negatively or positively, depending on the operating temperature and pressure. At a given temperature, the pressure dependence of solubility and permeability could be described empirically by an exponential function. The limiting solubility at infinite dilution was correlated with the reduced temperature of the permeant. The separation of volatile organic compounds (VOCs), which are more condensable than olefin gases, from nitrogen stream by the thin film PEBA composite membranes for potential use in gasoline or other organic vapour emission control was also studied. The membranes exhibited good separation performance for both binary VOC/N2 and multi-component VOCs/N2 gas mixtures. The permeance of N2 in the VOC/N2 mixtures was shown to be higher than pure N2 permeance due to membrane swelling induced by the VOCs dissolved in the membrane. The effects of feed VOC concentration, temperature, stage cut, and permeate pressure on the separation performance were investigated. Additionally, hollow fiber PEBA/polysulfone composite membranes were prepared by the dip coating technique. The effects of parameters involved in the procedure of polysulfone hollow fiber spinning and PEBA layer deposition on the permselectivity of the resulting composite membranes were investigated. Lab scale PEBA hollow fiber membrane modules were assembled and tested for CO2/N2 separation with various flow configurations using a simulated flue gas (15.3% carbon dioxide, balance N2) as the feed. The shell side feed with counter-current flow was shown to perform better than other configurations over a wide range of stage cuts in terms of product purity, recovery and productivity.

Advanced Methods, Materials, and Devices for Microfluidics Celesta E. White 217 Pages Directed by Dr. Clifford L. Henderson Microfluidics is a rapidly growing research area that has the potential to influence a variety of industries from clinical diagnostics to drug discovery. Unlike the microelectronics industry, where the current emphasis is on reducing the size of transistors, the field of microfluidics is focusing on making more complex systems of channels with more sophisticated fluid-handling capabilities, rather than reducing the size of the channels. While lab-on-a-chip devices have shown commercial success in a variety of biological applications such as electrophoretic separations and DNA sequencing, there has not been a significant amount of progress made in other potential impact areas for microfluidics such as clinical diagnostics, portable sensors, and microchemical reactors. These applications can benefit greatly from miniaturization, but advancement in these and many other areas has been limited by the inability or extreme difficulty in fabricating devices with complex fluidic networks interfaced with a variety of active and passive electrical and mechanical components. Several techniques exist for the fabrication of microfluidic devices, but these methods have significant limitations, and alternative fabrication approaches are currently desperately needed. One such method that shows promise for its ability to integrate the desired high levels of functionality utilizes thermally sacrificial materials as place holders. An encapsulating overcoat material provides structural stability and becomes the microchannel walls when the sacrificial material is removed from the channel through thermal decomposition. Disadvantages of this method, however, include numerous processing steps required for sacrificial layer patterning and elevated temperatures needed for the decomposition of initial sacrificial materials. These limitations keep this method from becoming an economical alternative for microfluidic device fabrication. The materials needed for this method to reach its full potential as a valid fabrication technology for m-TAS are not currently available, and it was a major focus of this work to develop and characterize new sacrificial materials, particularly photosensitive polycarbonate systems. In addition to the development of new sacrificial polymers, the framework for a working microfluidic device was developed to show that this concept will indeed provide significant advancements in the development of future generations of microfluidic systems. Finally, novel fabrication methods for microfluidics through combined imprinting and photopatterning of photosensitive sacrificial materials was demonstrated.

Three series copolyesters [poly(butylene succinate-co-propylene succinate) (PBPSu), poly(butylene succinate-co-2-methyl-1,3-propylene succinate) (PBMPSu) and poly(ethylene succinate-co-butylene succinate) (PEBSu)] and their homopolyesters [poly(butylene succinate) (PBSu), poly(ethylene succinate) (PESu), poly(propylene succinate) (PPSu) and poly(2-methyl-1,3-propylene succinate) (PMPSu)] were synthesized by a two-step reaction (esterification and polycondensation) with titanium tetraisopropoxide as the catalyst. Molecular weights of all synthesized polyesters were determined by intrinsic viscosity and gel permeation chromatography (GPC) measurements. The values of intrinsic viscosity (0.97 ~ 1.62 dL/g) and relative molecular weight (2.4x10000 ~ 11.9x10000 g/mol) indicate that these polyesters can be made into films without complications. Compositions and sequence distributions of copolyesters were determined by analyzing the spectra of 1H NMR and 13C NMR. The randomness values of these copolyesters are closed to 1.0 that represents random sequence distribution of the comonomers. Thermal properties and stabilities were characterized using differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA), respectively. All copolyesters exhibited a single glass transition temperature (Tg). For PBPSu copolyesters, incorporating propylene succinate units to PBSu not only narrows the window between Tg and melting temperature (Tm), but also retards the cold crystallization ability, thereby lowering the crystallinity to a considerable extent. This phenomenon also occurred in PBMPSu and PEBSu copolyesters when the 2-methyl-1,3-propylene succinate (MPS) and butylene succinate (BS) units were incorporated into PBSu and PESu, respectively. Tstart is the temperature of first detectable deviation from the derivative curve of weight loss. Tstarts of all synthesized polyesters around 240 £jC, higher than the temperature of polycondensation reaction (220 £jC), demonstrates that there is no necessity of using a thermal stabilizer during the synthesis of these polyesters. Additionally, the thermal stability does not vary significantly with compositions in the same series polyester. Wide-angle X-ray diffractograms (WAXDs) at room temperature were obtained from polyesters crystallized isothermally at a temperature around 5-20 £jC below their melting temperatures. WAXD patterns of two series polyesters elucidated that the incorporation of PS or MPS units into PBSu markedly inhibits the crystallization behavior of PBSu. The phenomenon also occurred in PEBSu copolyesters when BS units were incorporated into PESu. Results of WAXD and DSC measurements showed that PMPSu is a amorphous polyester. The retarding effect on crystallization by methyl substituents on the polymer chain is efficient.