Group 13 metals play a pivotal role in many areas of research ranging from materials to environmental chemistry. An important facet of these disciplines is the design of discrete molecules that can serve as functional materials for electronics applications and modeling studies. A solution-based synthetic strategy for the preparation of discrete Group 13 hydroxo-aquo tridecamers with utility as single-source precursors for amorphous functional thin film oxides is introduced in this dissertation. Several techniques including 1H-Nuclear Magnetic Resonance (NMR) spectroscopy, 1H-Diffusion Ordered spectroscopy, Solid-state NMR, Dynamic Light Scattering, and Raman spectroscopy are used to acquire structural information necessary for understanding the nature of these precursors in both the solid and solution phases. The dynamic behavior of these compounds has encouraged additional experiments that will pave the way for new studies with significant importance as the environmental ramifications of these compounds become relevant for future technologies. This dissertation includes previously published and unpublished co-authored material.

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-06-07T16:16:38Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2011-Dissertacao-JacyaraMariaVieira.pdf: 2851659 bytes, checksum: 9717f3b39ee72a29e0b2d9b0da8e4807 (MD5) / Made available in DSpace on 2017-06-07T16:16:38Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) 2011-Dissertacao-JacyaraMariaVieira.pdf: 2851659 bytes, checksum: 9717f3b39ee72a29e0b2d9b0da8e4807 (MD5) Previous issue date: 2011-09 / Ointeresse pelos estudos de biocombustíveis produzidos a partir de óleos vegetais iniciou-sena década de 80, em 1989,por Rudolf Diesel,com a utilização do óleo de amendoim. Por apresentar um teor de 54% de óleo extraído da amêndoa de seu fruto, a oiticica integra uma das novas fontes de oleaginosas estudadas para inserção na matriz energética brasileira para produção de biodiesel. Éuma árvore que pertence a família das Crysobalanaceae,é típica do semiárido nordestino e pode ser encontrada nos estados do Ceará, Paraíba, Piauí e Rio Grande do Norte.Porém, este óleo apresenta característicadeviscosidade eacidez elevadaso que impede seu uso direto na transesterificação. Para tratar a acidez e viscosidade foi realizada uma purificação por degomagem seguida de uma esterificação ácida. O óleo de oiticica apresentou excelente decaimento de acidezapós os tratamentos de degomagem e esterificação aplicados. A degomagem reduziu a acidez em 54,13%(de 15,24 para 6,99 mgKOH/g)e após a esterificação esta acidez foi reduzida em 75,8%(de 15,24 para 2,88mgKOH/g), mostrando a eficiência do processo e a possibilidade de utilização na produção de biodiesel. O óleo bruto e os resultadosde óleo degomado e esterificado foram caracterizadospor análises termogravimétricas, densidade, viscosidade, índice de acidez e índice de saponificação.Com os resultados de densidade e acidez observou-se a influencia do tipo de degomagem utilizadanestes, sendo a aquosa a que apresentou melhor resultado. No processo de esterificação foi analisado a relação álcool:óleo (6:1 e 12:1), o tipo de álcool (metanol e Etanol), o percentual de catalisador (0,1 e 0,7%) e a temperatura (35°C e 75°C) mostrando que a relação álcool óleo e o percentual de acidez influenciam na esterificação sendo a melhor curva de decaimento com 12:1 álcool:óleo, 0,7% de catalisador e 75°C e metanol. Concluindo que estes parâmetros influenciam diretamente no processo sendo a relação álcool:óleo e o percentual de catalisador os parâmetros mais importantes do processo. / Studies of biofuels produced from vegetable oils have emerged in the 1989's by Rudolf Diesel, the use of peanut oil. The Oiticica is atreefamily of Crysobalanaceae, is typical of semi-arid Northeast and can be found in the states of Ceara, Paraiba, Piaui and Rio Grande do Norte. The oil is extracted from the kernel of its fruit, and this corresponds to 54% oil content. The myrtle is inserted between the new sources of oil studied for inclusion in the Brazilian energy for biodiesel production due to high content of oil extracted from its seed. However, this oil has a characteristic viscosity and high acidity which prevents direct use in the transesterification. To treat the acidity and viscosity was performed followed by purification by a degumming acid esterification. Myrtle oil showed excellent acidity decay after degumming and esterification treatments applied. The degumming reduced the acidity in 54,13% and after this acid esterification was reduced by 81,10%, showing the efficiency of the process and the possibility of use in biodiesel production. The crude oil and the results of degummed and esterified were characterized by thermogravimetric analysis, density, viscosity, acid value and saponification index. The results of density and acidity influenced the type used for degumming, and the aqueous presented the best result. In the process of esterification was analyzed the alcohol: oil (6:1 and 12:1), the type of alcohol (methanol and ethanol), the percentage of catalyst (0.1 and 0.7%) and temperature (35 ° C and 75 ° C) showing that the alcohol percentage of oil and acidity influence the esterification being the best decay curve with 12:1 methanol: oil, 0.7% catalyst and 75 ° C and methanol. Concluding that these parameters directly influence the process and the alcohol: oil and the percentage of catalyst the most important parameters of the process.

The modern critics offer two different approaches regarding characterization in Golden Age Spanish theatre. The first approached, used by the majority of literary critics, consists in assuming that that the reader has to discover something that is hidden in the text. According to this approach, stage characters are creations of the author who, like a great architect, produces personalities that the reader has to discover. On the other hand, there are critics who claim that the characters have to be constructed by the reader. (José María Ruano de la Haza, Víctor Dixon). The main goal of my thesis is to elaborate a methodology for the constriction of dramatic characters and apply it to the six “prototypical” characters described in the classic study by Juana de José Prades.

Forward osmosis (FO) is an osmotically driven process that uses a high concentration draw solution to pull water across a semipermeable membrane from a feed solution. Wastewater, seawater, or other contaminated water sources may be used as a feed solution. In FO, the final product is not clean water but a diluted draw solution. However, FO may be combined with another process, e.g. reverse osmosis (RO). The resulting hybrid process offers advantages compared to the RO process in, for example, seawater desalination. Thin-film composite (TFC) membranes have been used in pressurized processes such as RO due to their thick porous support layer and their ability to endure high hydrostatic pressures. However, the presence of a thick porous layer is detrimental for FO processes. It is responsible for the internal concentration polarization (ICP) inside the membrane, reducing the osmotic driving force and the overall water flux. The characterization of membranes in FO applications is key for understanding how different intrinsic parameters affect membrane performance. In this work, a previously developed methodology for characterizing TFC membranes was improved. Experimental data was obtained from a laboratory-scale FO system, and the experimental data was used to determine three intrinsic transport parameters, namely the water permeance, the salt permeance and the porous layer structural parameter. With this method, the characterization of TFC membranes can be achieved based exclusively on FO data. A sensitivity analysis has highlighted the impact of the intrinsic transport parameters on an FO membrane performance.

Laser-induced breakdown spectroscopy (LIBS) has been established as a rapid, in situ, and real-time spectroscopic analytical technique for material characterization. It is very handy for the study of all kinds of materials irrespective of their state. After being used for a Mars mission, LIBS has gained global attention and many scientific researches are investigating its applications. The main objective of this dissertation is to study the possibility of using laser spectroscopic sensing techniques for material characterization and if possible, to develop methodologies. Studying molecular emission spectra for elemental analysis is a relatively new trend in the spectroscopic field. Molecular emission from SrCl and SrO observed in LIBS spectra were analyzed and compared with atomic emission from Sr. Calibration models were developed using both molecular bands and atomic spectral peaks. The determination of nutritional elements in crops, vegetables, and fruits is very important to evaluate their nutritional status. The LIBS technique was applied to identify the nutritional elements present in cauliflower and broccoli, and to evaluate the difference between organic and conventional vegetables in terms of nutritional elements. Principal component analysis (PCA) and one-to-one comparison using Student's t-test were employed for discrimination between organic and conventional vegetable flowers. Early iron and steel production in the state of Pennsylvania (United States) mostly utilized blast furnaces that were operated by charcoal as a primary fuel, followed by anthracite, then coke. The process left behind a by-product known as blast furnace slag. Blast furnace slag, non-metallic in nature, appears to have various industrial applications. LIBS was used for the analysis of charcoal blast furnace slags and qualitative as well as quantitative analyses were demonstrated. To evaluate the possibility of using the LIBS technique to detect and quantify rare earth elements, three consecutive studies were executed. Firstly, pure oxides of six rare earth elements were studied and then real samples directly taken from natural ores were analyzed. In the third step, two rare earth elements (Eu and Yb) in aqueous solutions were studied by underwater LIBS and the pressure effect on the plasma emission is discussed.

A test system was commissioned to characterize commercial thermoelectric modules to be used in the Pizza Oven Waste Energy Recovery (POWER) system for Pizza Pizza restaurants. The objective of this testing was to obtain and classify the thermoelectric material parameters of the Bi2Te3 within commercial thermoelectric generator (TEG) modules. These parameters consisted of the Seebeck coefficient, the thermal conductivity and the electrical resistivity. Together they provide the normalized figure of merit for the thermoelectric material which is a performance indicator for energy efficiency at a given operating temperature. From this research, a two phase methodology was developed that was able to extract the desired values from these modules. Material quality and device composition was first assessed with tools such as SEM and EDS. During this phase, dimensional and elemental data was gathered and a finite element model was constructed to ensure the validity of the primary selected test method for this research which was the Harman technique. The results obtained with this method were all three of the aforementioned thermoelectric parameters as well as a direct measurement of the figure of merit. Thermal and electrical losses for the TEG1B-12610-5.1 module were characterized from room temperature to 200°C using this process. It was determined that the thermal losses were more dominant and could be approximated using a function of T4 to within 1% of their calculated values. This process can be applied to any model of TEG to forecast these losses. To assist with future research, a secondary test method known as the Parallel Thermal Conductance technique was researched and a proposed model of it was designed for use in temperatures up to 300°C. Due to the relatively short test time of the Harman Technique, it was also used to effectively bin incoming groups of TEGs used in the POWER system so that they could be placed strategically in different areas of heat flow based on their measured performance. An increase of 13.2% was observed in the electrical output of the system after the binning had occurred. / Thesis / Master of Applied Science (MASc)

This study attempted to classify the characters in Greene's dramas and among other things, the study tried to show which characters are individuals and which are types.

Abstract Heavy metals are used in many industrial processes and their cations are either valuable or environmentally harmful to discharge in wastewater. Thus, it is necessary to separate heavy metals in wastewater treatment. Amongst several technical methods of separation, use of permeable membranes is an important one. For separation processes, membranes can be selective towards a target heavy metal cation either against mono-valent common cations or against other similar heavy metal cations. Synthesis of selective permeable membranes for separation purposes is an area of continuous research to meet specific needs in different applications. One of the common applications of selective separation by a permeable membrane is cation/anion separation processes using cation exchange and anion exchange membranes. Another application of selective permeable membranes is the separation of mono-valent cations from other higher valence cations. Some researchers have focused on specific selective separation of heavy metal cation from other heavy metal cations having the same valent charge. Some use chelating particulates dispersed in a neutral polymeric membrane matrix and others applied a thin chelating film on the surface of a commercial cation exchange membrane. In this work, the synthesis of novel permeable selective membranes and their use for selective separation between two di-valent heavy metal cations is presented. Three different sets of membranes were prepared in non-imprinted and imprinted forms. The ion imprinted membranes form is prepared by pre-reacting the target metal ion with the selective chelating monomer before applying in situ polymerization step, and in the non-imprinted membranes form this step is not considered. Their morphological and chemical structures were determined and their separation performances were investigated using a diffusion dialysis technique. The first membrane (non-imprinted polyvinylidene fluoride-divinylbenzyl-triethylenetetramine (PVDF/diVB-TETA) and Cu-imprinted PVDF/diVB-TETA-Cu forms) was prepared by in situ polymerization of the chelating monomer divinylbenzyl-triethylenetetramine diVB-TETA (or diVB-TETA-Cu) within a PVDF substrate, using a divinylbenzene cross-linker. Fourier transform infrared FT-IR spectroscopy showed the successful in situ polymerization of the chelating monomer within the PVDF texture. The permeation study showed that the ion-imprinted membrane has a Cu2+ selectivity factor of 3.78, while the non-imprinted membrane has a Cu2+ selectivity factor of 1.65. In addition the Cu2+ permeation flux in the imprinted membrane is 3.9 time that in the non-imprinted membrane For the second membrane, the synthesis is similar to the first membrane for both non-imprinted and imprinted forms (polyvinylidene fluoride-divinylbenzyl-triethylenetetramine-N,N'-methylenebis(acrylamide) (PVDF/diVB-TETA-N) and PVDF/diVB-TETA-N-Cu respectively), except that the used cross-linker was N,N'-methylenebis(acrylamide). In addition, sodium 4-vinylbenzyl sulfonate was added in selected percentages, (5-15% mol), to enhance the permeation flux. FT-IR spectroscopy analysis of the prepared membranes confirmed the chemical structure of diVB-TETA-N and sulfonate group into PVDF. Permeation and selective separation studies for the prepared membranes showed that the ion-imprinted membrane has a higher selectivity for copper permeation over the non-imprinted membrane. However imprinted membrane showed a lower flux for the permeated cations than that of the non-imprinted membranes The addition of the sulfonate groups to the prepared membranes enhanced the flux of the permeated cations, but the copper selective permeation decreased for both types (non-imprinted and ion-imprinted). Moreover, the ion-imprinted membrane PVDF/diVB-TETA-N-Cu showed a lower flux for the permeated cations than that of the non-imprinted membranes PVDF/diVB-TETA-N. Selective separation factors decreased to unity when the content of the sulfonate groups increased to 15% mol. Ion imprinted membrane prepared with 10% of sulfonate group showed optimum copper selectivity factor (α = 30304) and permeation flux for copper (0.4949 μmol cm‒2 h‒1) The third membrane (non-imprinted Selemion TM cation exchange membrane-divinylbenzyl-triethylenetetramine (CMV-S/diVB-TETA) and ion-imprinted CMV-S/diVb-TETA-Cu forms) was prepared by in situ polymerization of the chelating monomer, diVB-TETA (or diVB-TETA-Cu), on the surface of the commercial cation exchange membrane, Selemion, using divinylbenzene as cross-linker. FT-IR spectroscopy confirmed the chemical structure of the chelating polymer on the CMV-S membrane surface. Permeation study showed that ion-imprinted CMV-S/diVB-TETA-Cu membrane reached high separation factor (α = 17), yet the flux is low (0.0391 μmol cm‒2 h‒1). Non-imprinted CMV-S/diVB-TETA membrane of thickness (0.115±0.005 mm) using cross-linker (10% DVB) showed reasonable copper selectivity factor (α = 2.723) and permeation flux (0.433 μmol cm‒2 h‒1) / Thesis / Doctor of Philosophy (PhD)

Fine/nanoscale carbonitrides of microalloying elements such as Nb, Ti, and V play a significant role in the strengthening of HSLA steels. Site-specific analysis of the precipitates in different heterogeneous microstructural areas within realistic alloys is limited and the competition of different precipitates has not been discussed in detail. In this work, the relationship of precipitates/clusters with microstructure has been analyzed by site-specific methods and a simple model has been created to describe the competition between strain-induced precipitation and (Ti, Nb) (C, N). Firstly, the spatial distribution of precipitates and microstructure heterogeneity in an X70 steel were investigated by site-specific analysis method. The quantitative analyze the precipitates reveals that strain-induced precipitation of fine NbC particles (5-20 nm) on dislocations was suppressed by the large (Ti, Nb) (C, N) precipitates. The similarity of precipitates in each location suggests that the local features (such as strain and grain size) in the final microstructure arise from phase transformations during cooling. Secondly, the microstructural evolution during coiling and its effects on the mechanical properties of a vanadium microalloyed steel were investigated. Experimental findings showed that during holding at 500 ºC, nano precipitates (<10 nm) containing V and N nucleated heterogeneously, primarily in areas with high Kernel Average Misorientation (KAM) values. These areas contained a larger number of dislocations, which acted as nucleation sites for the precipitates. The effect of precipitation strengthening was not significant and was offset by softening caused by the aging of bainite and associated recovery of dislocations. Thirdly, in the HSLA steel with both V and Nb additions, nano precipitates were found to preferentially form around dislocations and grain/sub-grain boundaries in high KAM areas associated with bainite. Precipitates were frequently observed around cementite in low KAM areas, which were identified as granular bainite. Interphase clusters were also discovered in low KAM areas behind the ferrite/austenite interface. Analysis of the results indicated that the precipitation of micro-alloyed particles on cementite may reduce the contribution of precipitation hardening achievable through microalloying. Finally, a competition model between strain-induced precipitates (SIP) and epitaxial growth in micro-alloyed austenite has been developed. Using this model, it is possible to estimate the effects of process parameters (T, applied strain), the number density of pre-existing TiN particles, and steel composition on the precipitation process. Through the various studies achieved here, the aim to understand the relationship between the precipitates and different microstructures and develop the competition models has been accomplished. These works provide a relatively new workflow to investigate the precipitates within the steel, especially in site-specific areas, and also allow us to predict the precipitation of NbC by selecting desired temperature range, applied strain, and number density of pre-existing TiN precipitates. / Thesis / Doctor of Philosophy (PhD)

No description available.