Made available in DSpace on 2014-10-09T12:37:17Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:09:07Z (GMT). No. of bitstreams: 1 02044.pdf: 6648951 bytes, checksum: 98f65fdf18484fade28803cf88a3e67d (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

O presente trabalho teve como objetivo a avaliação do desempenho de 36 bovinos castrados Nelore confinados durante 100 dias de experimentação. Os tratamentos foram: controle (sem ionóforo), 44 mg de lasalocida/kg de (MS) matéria seca de concentrado e 44 mg de monensina/kg de MS de concentrado. Como fonte de volumoso, foi utilizado feno de Coast-Cross (Cynodon dactylon) na proporção de 30% da MS da dieta total. Não houve efeito da suplementação de monensina e lasalocida sobre as concentrações sangüíneas de glicose e uréia. Após 35 dias de experimento, foi observada redução da ingestão de matéria seca dos animais submetidos ao tratamento com monensina, sendo -6,3% e -5,9% em relação aos animais do grupo controle e aos do tratamento com lasalocida, respectivamente (P<0,05). No que se refere ao demais parâmetros de desempenho, não foram observadas diferenças significativas no ganho médio diário (havendo apenas tendência, onde P<0,1668), eficiência alimentar, rendimento de carcaça, área de olho de lombo e espessura de gordura subcutânea no decorrer do experimento / The present study was conducted to estimate performance of 36 castrated Nelore steers, in feedlot during 100 days of experiment. Treatments were: control (no ionophore), 44 mg of lasalocid/kg of concentrate in dry matter (DM) and 44 mg of monensin/kg of concentrate in DM. As forage, it was used Coast-Cross (Cynodon dactylon) hay, in 30% of total ration. There was not effect of monensin and lasalocid supplementation in blood glucose and urea concentrations. After 35 days of experiment, the dry matter intake decreased in monensin group, with -6,5% and -5,9%, for control and lasalocid groups (P<0,05). For other performance parameters, there were not significant diferences in daily gain (only tendence, with P<0,1668), feed efficiency, carcass dressing percentage, rib eye area and subcutaneous fat thickness through the experiment

Experiment one revealed fishmeal (FM) replacement with soy protein concentrate (SPC) alone, and in combination with pea protein concentrate (PPC) and saponins (S) modulated the intestinal bacterial communities of D. labrax, increasing the presence of lactic acid bacteria. Intestinal histology revealed significantly reduced goblet cell’s (GC’s) in fish fed the SPC+S, epithelial microvilli densities (MD) in fish fed the SPC+PPC, SPC+PPC+S and SPC+S after two weeks feeding. Significant reductions in GC’s and intraepithelial leukocytes (IEL’s) in fish fed the SPC+S, and MD’s in fish fed the SPC+S and SPC+PPC+S after four weeks feeding, relative to fish fed the FM control. Furthermore, fish fed all plant based diets appeared to exhibit a loss of membrane integrity at the microvilli tips, most pronounced in fish fed the SPC+S diet. These results suggest a sub-acute enteritis response in the posterior intestine of D. labrax, which was deemed to be most pronounced in fish fed the SPC+S diets. Experiment two utilised the SPC+S diet as a sub-optimal basal diet to assess the potential of the probiotic Bacillus subtilis and the prebiotic Previda®, individually and in combination, in alleviating the enteritis-like effects induced by this diet, observed in the first experiment. Microbiological analyses revealed B. subtilis modulated the allochthonous bacterial communities. Fish fed the combination of B. subtilis and Previda® (synbiotic) diet exhibited a significantly increased intestinal perimeter ratio, compared to fish fed the basal. Significantly elevated GC’s in fish fed the probiotic and synbiotic treatments, and significantly elevated epithelial MD’s, and intestinal absorptive surface index in fish fed the probiotic diet was observed, relative to fed fish the basal. The loss of membrane integrity induced by the basal diet, was reduced in fish fed the probiotic, prebiotic and synbiotic diets. The intestinal gene expression of the pro-inflammatory cytokines IL-1β and TNFα was significantly up-regulated in fish fed all experimental diets, relative to fish fed the basal. The intestinal gene expression of HSP70, CASP3 and PCNA was significantly down-regulated in fish fed the probiotic, prebiotic and synbiotic relative to fish fed the basal. At the end of the experiment intestinal samples were exposed to one of four treatments [1. PBS (control), 2. B. subtilis, 3. Vibrio anguillarum and 4. B. subtilis + V. anguillarum], ex vivo, to determine if the feed additives could mitigate enteric pathogen damage. All feed additives revealed the potential to reduce the morphological damage caused by the pathogen. Experiment three assessed B. subtilis and the phytobiotic Next Enhance 150® on the growth and health of D. labrax. B. subtilis modulated the allochthonous bacterial communities and reduced the presence of some potential pathogens. The intestinal gene expression of HSP70, CASP3, PCNA and CAL was significantly down-regulation in fish fed the probiotic diet relative to fish fed the control. Significantly elevated IEL’s were observed in fish fed the probiotic and Next Enhance 150® diets relative to fish fed the control. Growth performance was remained unaffected. The present research demonstrates that dietary B. subtilis modulates the allochthonous bacterial communities, as well as, improving the intestinal morphology and localised immunity in European sea bass. Dietary Previda® and Next Enhance 150® were also observed to confer beneficial effects on the gut health of this species. No detrimental effects were observed as a consequence of any of the feed additives used in the present research.

The possibility of using waste vegetable oil from deep-frying processes as a fuel for long term use in diesel engines was investigated. Research was aimed at using existing technology in terms of engine design in order to utilize a maximum amount of waste vegetable oil as the energy source with a minimum of processing. A small swirl-chamber diesel engine was selected and used to run the 200-hour test recommended by the EMA for testing vegetable oil-based fuels. A blend of 20/80 (waste oil/diesel fuel) was tested as well as a 50/50 blend. BSFC data for both blends did not indicate any significant deterioration in engine performance during the 200 hour tests for ail the fuels tested. However, the 50/50 blend BSFC data had more spread than the data from the 20/80 or the diesel baseline test. This was attributed to variable amounts of deposits on the injector nozzle throughout this test Carbon deposits on all other parts of the combustion chamber were comparable for all the fuels tested. Wear of the engine parts was also comparable except for the piston rings. Piston ring wear was greater with diesel fuel and smaller when burning the 50/50 blend. This was attributed to a film of unburned fuel on the cylinder wall that improved lubrication. Lower -lubricating oil consumption was also attributed to this film. The alternate fuel blends completed the 200 hour EMA screening test and could be considered as possible candidates for long-term use in I.D.I, engines. / Applied Science, Faculty of / Graduate

Lithium batteries have revolutionized emerging electronic applications and will play more important roles in the future. Unfortunately, the energy density of commercial lithium-ion batteries (100-265 Wh kg-1) cannot satisfy the fast-growing demand for energy storage technologies. Lithium-sulfur (Li-S) batteries stand out for high energy density (2567 Wh kg-1), low-cost, and environmentally benign attributes. However, the development of Li-S full-batteries is still hindered by the dissolution of polysulfides into the organic electrolytes and poor ions transfer at the interfaces of electrolytes and lithium-intercalated electrodes (e.g., lithiated graphite). Improving the electrolytes is a crucial aspect for the development of battery technologies, but the knowledge concerning the electrolyte microstructures remains elusive. This dissertation unravels the microstructures of organic electrolytes and paves the way to the development of Li-S batteries. Firstly, we demonstrate the key role of electrolyte chemistry in the battery performances by showing a synergetic effect of electrolytes coupled with designed sulfur cathodes. Secondly, we investigate the microstructure of electrolytes and discover previously unexplored solvent-solvent and solvent-anion interactions. We show that the interactions are useful to elucidate important battery operations, such as ions transfer at electrolyte-electrode interfaces, and reveal a potential probe for developing battery electrolytes. Thirdly, we optimize the electrolyte composition to obtain a highly reversible Li+ intercalation/deintercalation at the graphite anode, giving high performances of Li-S full-batteries in a dilute electrolyte concentration. Finally, we unravel the key role of additives in suppressing Li+ solvation in the electrolytes. Nitrate (NO3-) anions are observed to incorporate into the solvation shells, change the local environment of Li+ cations, and then lead to an effective Li+ desolvation followed by improved battery performances. Key significances of this dissertation are (i) observation of detailed electrolyte microstructures showing a potential probe for developing battery electrolytes; (ii) evidences of the electrolyte chemistry plays a predominant role in the electrolyte-electrode interfacial reactions, which prevails over the role of commonly believed solid electrolyte interphase (SEI); and (iii) new mechanistic insights into the key role of additives in the electrolyte microstructures. Furthermore, the presented methodology paves the way for developing electrolytes for broad electrochemical applications.

Polymer additives exemplify many classes of compounds which possess a wide variety of chemical (i.e., phenols, amides, esters) and physical (i.e., volatility, solubility) properties. They are incorporated into polyolefins and other such polymeric materials for a number reasons: (a) to prevent degradation by ultraviolet light, heat, and oxygen; (b) to aid in the processing of the polymer; and (c) to modify the physical properties of the polymer. Since the purity and amount of additive can affect polymer properties, it is very important to characterize and quantify additives in polymer products. Traditional liquid solvent/polymer extraction methods, which involve dissolution/precipitation, are time-consuming, uneconomical, and the recoveries are significantly lower than 90%. In recent years, analysis with supercritical fluids (SFs) has emerged as an alternative analytical technique because SFs afford higher diffusivity and lower viscosity. In this research, an on-line Supercritical Fluid Extraction (SFE)/Supercritical Fluid Chromatography (SFC) system was assembled to provide efficient extraction and separation of polymer additives with quantitative results. The effects of various SFE/SFC parameters, such as trapping temperature, injection temperature, extraction pressure and temperature, dynamic extraction time, and fluid flow rate on extraction and separation efficiencies of different additive standards (i.e., BHT, BHEB, Isonox 129, Irganox 1076 and Irganox 1010) were investigated. Optimized conditions were employed to quantitatively extract additives from LDPE. Identification of additives was performed by comparing the retention time with each additive standard. Results obtained from on-line SFE/SFC were compared to results from off-line SFE/High Performance Liquid Chromatography (HPLC) and off-line Enhanced Solvent Extraction (ESE)/HPLC. / Master of Science

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This study focused on improvement of electroless plating methods by use of particular bath additives. The techniques developed here can enable us to plate very thin layers selectively on a nonconductive substrate and thus create metallized features on a nanoscale. Through the development of such bottom-up techniques this work contributes a key technology to achieving self-assembled nanocircuits. The use of additives in an electroless plating environment can modify the barriers to nucleation (or seeding) and growth. Two additives, namely 3-mercapto-1-propanesulfonic Acid (MPS) and 1,3-propanedisulfonic acid (PDS), notably increased the selectivity of electroless metallization on chemically modified surfaces, which can be used to create patterned structures. More specifically, the additives increased the growth rate of metal on an aminosilane-coated surface relative to an uncoated surface. This work includes an examination of metal layer thickness and conductivity in addition to selectivity. The layer thickness was determined through the use of atomic force microscopy on surfaces that exhibited conductivity. The conductivity of the surface metal was determined through a measurement on a four-point probe measurement. In this series of experiments, the disulfonate-containing additive PDS provided the highest nucleation density, highest conductivity and the best selectivity ratio. The palladium metal deposit on the PDS-treated surface was nearly uniform in height and its conductivity approached the bulk conductivity of palladium with a metal height of less than 30 nm. MPS-treated surfaces also provided increased nucleation density when used during the seeding step, but the resulting conductivity was less than that of the PDS treated samples. We recommend the use of PDS as an effective electroless plating additive for use in palladium electroless plating processes.

This research is directed to the characterization of the thermodynamic properties and viscosity of lubricant base oils modified with polymeric additives. Several groups of mineral and synthetic base oils, including Ultra S4, Ultra S8, and poly alpha olefin PAO 4 have been studied. Among the various types of additives explored were viscosity index modifiers, polyisobutylene polymers (PIBs), and dispersants. The viscosity index modifiers are studied in terms of different polymer architectures, molecular weights, presence or absence of functional groups, and their concentrations. The dispersants are studied in terms of concentration, molecular weight, and presence of capping groups. Density data, as the basic thermodynamic data, are generated using a high-pressure variable-volume view-cell over a pressure range from 10 to 40 MPa and a range of temperatures from 298 to 398 K. The density data are then correlated with the Sanchez-Lacombe equation of state, from which key thermodynamic properties, namely isothermal compressibility, isobaric expansivity, and internal pressure are derived. These properties offer a rational approach to better understand molecular packing in lubricants under high pressure and temperature conditions which has direct impact on film formation. Viscosity determinations are carried out using a custom-designed high-pressure rotational viscometer. Data were generated in the pressure range from 10 to 40 MPa, but at temperatures ranging from 298 to 373 K as a function of shear rate up to 1270 s-1. Viscosity data were then correlated with density which provides interpretations in terms of free-volume and density scaling models. The molecular parameters produced from these correlations support the interpretation of molecular packing under high pressure and temperature conditions. The results of this study included several key findings. With regards to density, the addition of viscosity index modifiers to Ultra S4 base oil caused the density to increase, except for the addition of functionalized olefin copolymers (OCPs) which caused the density to decrease. This was true with both high and low molecular weight additives. In the case of Ultra S8 base oil, the addition of OCPs generally decreased the density, while the addition of polymethacrylates (PMAs) caused the density to increase. In terms of compressibility and expansivity, the addition of high molecular weight viscosity index modifiers to Ultra S4 base oil generally decreased both these properties. However, the compressibility increased with the addition of 5 wt % functionalized PMA and 2 wt % star styrene butadiene (SSB). Furthermore, there was less of a decrease in compressibility with the addition of functionalized additives. With the addition of low molecular weight viscosity index modifiers to Ultra S4 base oil, little change was observed in compressibility, and the expansivity decreased to a lesser degree than with the addition of high molecular weight viscosity index modifiers. Viscosity index modifiers did not alter the compressibility of Ultra S8 base oil. Compared to Ultra S4, expansivity in Ultra S8 decreased to a lesser extent. The internal pressure was observed to be lowered to a greater degree in either Ultra S4 or Ultra S8 base oil with the addition of additives with more rigid internal structures (PMA and SSB). The decrease occurred to a greater degree with the addition of the higher molecular weight versions of additives studied and/or with the incorporation of functional groups to the additives. Although density changes were often greater with the addition of additives to the Ultra S8 base oil, all other derived thermodynamic properties, including internal pressure, changed to a greater degree with the addition of additives to the lower molecular weight Ultra S4 base oil. The viscosity generally increased to varying degrees with the addition of different additives to either base oil. The addition of functionality and higher molecular weight additives led to more consistent viscosity increases at higher temperatures. At the highest viscosity isotherm tested, 373 K, the addition of viscosity index modifiers resulted in similar viscosity values in either base oil, even though the viscosity of Ultra S4 at 373 K is much lower than the viscosity of Ultra S8 at this temperature. However, at 298 K, the viscosity index modifiers increased the viscosity of the Ultra S8 base oil to much higher values than the viscosity of the Ultra S4 base oil. Model based correlations of viscosity showed that with addition of high molecular weight viscosity index modifiers to Ultra S4 base oil, the parameters that are linked to free-volume overlap and the density dependence were more sensitive to the addition of OCPs than with the addition of PMAs and SSBs. These changes were reflected in larger free-volume overlap parameters and larger density exponent values. However, with a low molecular weight addition, the resulting parameters changed more with the addition of PMAs than OCPs. Overall, the addition of polymers with more rigid architecture led to more similar changes in correlative parameters across molecular weights from that of the original base oil, while for the OCP addition, the molecular weight had more of an influence on the degree of change. With addition of viscosity index modifiers to the Ultra S8 base oil, the architecture of the additive had more of an influence on the viscosity correlation parameters as the addition of PMA led to more noticeable changes in the parameters (resulting in lower free-volume overlap parameters, and a lower density exponent) than the addition of OCP, irrespective of the molecular weight or functionality. In either base oil, the addition of PMA led to lower free-volume overlap parameters and density exponent values than the addition of OCP. In this study it was observed that the addition of functionality, or polar groups to viscosity index modifiers, led to more desirable thermodynamic and rheological property changes to the lubrication base oil. This change was more definitive with the addition of polymers with more rigid architecture, such as PMAs and SSBs in contrast to the OCPs. The study on the addition of PIBs and capped or uncapped dispersants showed little variation in the resulting density and viscosity values when added to Ultra S4 base oil. However, the compressibility in these systems generally increased while the expansivity decreased except with the addition of PIBs. The internal pressure decreased to similar levels for all additive additions, except for the lowest molecular weight PIB, in which there was little change. The study on the addition of PIBs to different base oils showed that low molecular weight PIBs had the potential to disrupt the packing of a more uniform PAO 4 base oil and change the thermodynamic properties and correlation parameters to a greater degree than with the addition of higher molecular weight PIBs. This resulted in higher compressibility and internal pressure values with the addition of low molecular weight PIB compared to the higher molecular weight PIBs. However, there was little variation in viscosity with any of the PIB additions, except for the highest molecular weight PIB. / Doctor of Philosophy / Several legislations have recently been passed which are aimed at improving the fuel efficiency in cars. One way to improve fuel efficiency is to reduce friction through improvements on the lubrication systems such as engine oils and transmission fluids. This applies to lubricants operating under cold start conditions and up to operating condition of approximately 100ºC. Additionally, the lubricants are subject to extreme pressure conditions when they are squeezed between contacts such as gears or clutch plates. Therefore, it is crucial to explore lubricant performance under high pressure and temperature conditions. The lubricants that are preferred are those that form a layer that completely protects metal contacts without causing the contacts difficulty in moving, causing a loss in efficiency. The desired film layer thickness under high pressure and temperature conditions can be improved using different additives. This thesis explores high pressure and temperature behavior of lubricant systems modified with different types of additives using uniquely designed lab instrumentation. The focus is on understanding their volumetric and flow properties, which directly influence the film layer and effectiveness of the lubricant. Volumetric properties are characterized by measurement of density as a function of temperature and pressure. Density data provides insights on molecular packing in lubricant systems. Flow properties, specifically, resistance to flow, can help analyze a potential loss in efficiency caused by the lubricant systems. The thesis is thus a comprehensive study on the volumetric and flow properties of lubricants at a wide range of temperatures ( from 298 to 398 K) and pressures (from 10 to 40 MPa) and how these properties are affected in the presence of additives that aim to improve lubricant performance.