The presence of moisture in hot mix asphalt (HMA) causes loss of strength and durability of the mix, which is referred to as moisture damage. This study deals with the development of experimental methods for measuring total suction in HMA, which can be defined as the free energy state of water in HMA mixes. The total suction is related to the ability of moisture to get into the mix under unsaturated conditions; it is also related to the ability of the mix to retain moisture. Soil suction has been studied extensively. However, suction in HMA as a porous material and its relationship to moisture damage have not been studied. The development of a procedure to measure the total suction in HMA mixes is the first objective of this research. The second objective is to relate suction measurements to physical and chemical properties of the mixtures. The objectives were achieved in two phases. In the first phase, the total suction was measured in HMA specimens with different types of aggregates (limestone and granite), and with different air void distributions and aggregate gradations. The results of this phase showed that the drying test using a 60 oC temperature-controlled room is the proper setup for measuring the total suction in HMA using thermocouple psychrometers. The characteristics of suction-moisture content curves were found to be related to the air void distribution in HMA. In the second phase, total suction was measured in sand asphalt specimens. These specimens had different combinations of aggregates and binders with different bond energies and exhibited different field performance in terms of resistance to moisture damage. The suction measurements in sand asphalt specimens were used to calculate the moisture diffusion coefficient. The results revealed that water diffused into sand asphalt specimens that are known to have poor resistance to moisture damage faster than those that are known to have good resistance to moisture damage

Diffusion behavior of spin cast polymer thin films was studied in detail as a function of film thickness. Diffusion coefficients of water molecules in poly(methyl methacrylate) (PMMA) were found to decrease from 10-8 cm2/s in thick films to 10-13 cm2/s in ultra-thin films. In order to probe if there is a characteristic length scale set by the polymer chain size, the effect of PMMA molecular weights on this behavior was tested and deviation of diffusion coefficient from bulk was observed in all molecular weights of PMMA investigated. Diffusion coefficients in these films was also studied as a function of aging time at 25°C and was not found to change significantly over a time period of approximately four months. The impact of residual casting solvent in thick and thin films was studied and found to have no influence in the diffusion behavior. Positron Annihilation Lifetime Spectroscopy (PALs) was used to probe the free volume (FV) pocket size and its distribution within the film as a function of film thickness in PMMA. Decrease in FV pocket size was found to be one of the general underlying causes for such thickness dependent diffusion behavior observed in thin polymer films. In addition, Protracted Colored Noise Dynamics (PCND) that enables efficient sampling of phase space and faster relaxation of the systems compared to Molecular Dynamics (MD) was investigated for its extensibility to three dimensional systems and was found to be sensitive to initial conformation.

Orientador: Wagner dos Santos Oliveira / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-26T01:59:47Z (GMT). No. of bitstreams: 1 Costella_AngelaMaridosSantos_D.pdf: 2192700 bytes, checksum: ae7511fd86ad26645308ac10b59cd93e (MD5) Previous issue date: 2014 / Resumo: Os materiais restauradores para uso odontológico visam restituir os tecidos dentários danificados pelos efeitos do ambiente bucal, que pode causar danos por atrito, abrasão, erosão e cáries. O presente trabalho teve como objetivo principal formular e caracterizar compósitos experimentais para uso como materiais restauradores dentários, visando relacionar as características de composição destes materiais às suas propriedades finais, bem como desenvolver uma formulação que reúna condições satisfatórias para a sua utilização como material restaurador. Tendo em vista que a complexidade da formulação dos materiais dentários comercialmente utilizados dificulta o estudo de suas características, neste trabalho, a formulação das resinas experimentais priorizou a variação da composição da parte orgânica do compósito com o objetivo de facilitar a avaliação de sua influência sobre as propriedades finais dos materiais obtidos. Os compósitos formulados contêm como principais componentes dióxido de silício silanizado e de alta pureza possuindo partículas de tamanho nanométrico e uma mistura de polímeros dimetacrilatos, obtidos via reação radicalar em cadeia e utilizando-se fonte de Luz Halógena. Os monômeros utilizados para a obtenção das formulações são conhecidos comercialmente como: bisfenol A glicidilmetacrilato ou dimetacrilato glicerolato de bisfenol A, dimetacrilato etoxilato de bisfenol A e trietileno glicol dimetacrilato. A caracterização dos materiais obtidos foi realizada através de espectroscopia de infravermelho, análise dinâmico mecânica, calorimetria diferencial exploratória, análise termogravimétrica, medidas de índice de refração, testes de sorção e difusão, medidas de ângulo de contato e ensaios de dureza. Os materiais foram analisados segundo o grau de conversão, características físicas, propriedades termomecânicas, sorção de água e coeficiente de difusão. Os resultados obtidos foram comparados aos resultados obtidos para materiais semelhantes / Abstract: Restorative materials for dentistry purposes must recover tooth tissues damaged by oral environmental adverse effects as friction, abrasion, wear and caries. The main purpose of this work was the development and characterization of resin composites for dental restoration purpose intending to establish the relationship of composition characteristics and final properties and achieve a composition suitable for restorative purpose. Taking into account the complex formulation involved in the typical restorative composites, commercially available, in this work we regard mainly the organic portion of the compound to the aim further evaluations of its influence on the final properties of composites materials. The obtained composites are constituted by high purity surface modified nanosilica dioxide and dimethacrylate polymers, obtained by chain radicalar reaction. The monomers used are commercially known as Bisphenol A glycol dimethacrylate, Bisphenol A ethoxylated dimethacrylate and Triethylene glycol dimethacrylate. The polymerization process was performed using a halogen lamp source. The obtained composites were studied with respect to degree of conversion, physical characteristics, thermomechanical properties and water sorption and diffusion process. Infrared spectroscopy, thermal mechanical analysis, differential scanning calorimetry , thermogravimetric analysis, refractive index, contact angle and hardness tests, water sorption uptake and diffusion tests were performed for materials characterization. For comparison purposes the obtained data were compared to similar materials / Doutorado / Engenharia Química / Doutora em Engenharia Quimica

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The dynamic of cavitation in hydraulic components cannot be computed accurately yet and therefore cavitation is hard to predict. The cavitation phenomenon can be divided in three sub-phenomenona: Pseudo-cavitation, Gas-cavitation and Vapour-cavitation. Pseudo-cavitation discribes the enlargement of an air bubble due to a pressure drop. Gas-cavitation refers to bubble growth which is driven by diffusion of dissolved air from the surrounding fluid into the bubble, when the solubility of air in the fluid is lowered by a pressure drop. Vapor-cavitation is the evaporation of the liquid phase on the bubble surface. Usually all three sub-phenomenona occur simultaneously when the pressure decreases and are summarised as cavitation in general. To implement the physics of gas-cavitation in a dynamic mathematical model it is necessary to know the diffusion coefficient of air in the hydraulic liquid and the maximum amount of air which can be dissolved in the liquid. The calculation can be accomplished by using the Bunsen coefficient. In this paper both coefficients for three different hydraulic oils are calculated based on experimental results.

It would be beneficial to incorporate transmembrane proteins (TMPs) into biosensors, because TMPs are important for cell function in healthy and diseased states. These devices would employ an artificial cell membrane to maintain TMP function since cell membranes, which are mostly lipids, are necessary for the TMPs to function. These artificial lipid membranes must be robust for sensor applications. The ruggedness of these artificial membranes can be increased by using polymerizable lipids. Some polymerized lipid membranes exhibit increased stability, while successfully incorporating TMPs.Some polymerized membranes do not support the activity of certain TMPs, while maintaining the function of others. It is believed the physical properties of the membranes are important for TMP function. Some important physical properties of polymerizable lipid membranes have not yet been measured. Here, fluidity and mechanical properties of polymerizable dienoylPC lipid membranes were investigated.Fluorescence Recovery After Photobleaching was used to measure the fluidity of polymerizable dienoylPC membranes. Unpolymerized, UV-polymerized, and redox-polymerized membranes were investigated. Three types of membranes were found: fluid, partially fluid, and immobile. Unpolymerized and some polymerized membranes were fluid, while only polymerized membranes were partially fluid or immobile. Polymer size is believed to cause the differences in fluidity. This study highlights how polymerization parameters can influence membrane fluidity.Micropipette Aspiration was used to measure the mechanical properties of Giant Unilamellar Vesicles (GUVs) composed of dienolyPC lipids. Unpolymerized and UV-polymerized GUVs were investigated. Strength measurements showed that denoylPC GUVs were stronger than sorbylPC GUVs. Area expansion moduli of denoylPCs and mono-SorbPC GUVs were slightly lower than SOPC GUVs, while bis-SorbPC GUVs were substantially easier to stretch. The bending moduli of all GUVs was similar. UV-polymerization had no significant effect on the parameters. The difference in strength between denoylPCs and sorbylPCs is hypothesized to be due to the porous nature of sorbylPCs. It is thought UV-polymerization of these GUVs created polymers too small to significantly alter mechanical properties.It was demonstrated that some stable membranes are also fluid, which is important for the function of certain TMPs. A correlation cannot be made between the bending and stretching moduli of polymerizable membranes and function of TMPs.

Cancer is one of the major causes of worldwide mortality. Imaging plays a vital role in the staging, follow-up, and evaluation of therapeutic response in cancer patients. Whole-body (WB) magnetic resonance imaging (MRI), as a non-ionizing imaging technique, is a promising procedure to assess tumor spreading in a single examination. New MRI technological developments now enable the application of diffusion-weighted imaging (DWI) of the entire body. DWI reflects the random motion of water molecules and provides functional information of body tissues. DWI can be quantified with the use of the apparent diffusion coefficient (ADC). The aim of this dissertation was to demonstrate the value of WB MRI including DWI in cancer patients. WB MRI including DWI, 18F-NaF PET/CT, and bone scintigraphy was performed on 49 patients with newly diagnosed, high-risk prostate cancer, for the purpose of detecting bone metastases. WB DWI showed higher specificity, but lower sensitivity compared to 18F-NaF PET/CT. In addition, WB MRI including DWI, and CT of the chest and abdomen was performed in 23 patients with malignant melanoma. We concluded that WB MRI could not completely supplant CT for the staging of malignant melanoma, especially with respect to the detection of lesions in the chest region. In this study, WB MRI and DWI were able to detect more bone lesions compared to CT, and showed several lesions outside the CT field of view, reinforcing the advantage of whole-body examination. WB MRI, including DWI, was performed in 71 patients with testicular cancer. This modality demonstrated its feasibility for use in the follow-up of such patients. WB MRI, including DWI, and 18F-FDG PET-CT, were carried out in 50 patients with malignant lymphoma. Both these imaging modalities proved to be promising approaches for predicting clinical outcomes and discriminating between different subtypes of lymphomas. In conclusion, WB MRI, including DWI, is an evolving technique that is continuing to undergo technical refinement. Standardization of image acquisition and analysis will be invaluable, allowing for more accurate comparison between studies, and widespread application of this technique in clinical practice. Both WB MRI, including DWI and PET/CT, have their particular strengths and weaknesses in the evaluation of metastatic disease. DWI and PET/CT are different functional techniques, so that combinations of these techniques may provide complementary and more comprehensive information of tumor tissue.

Soil CO2 efflux (F-soil) represents a significant source of ecosystem CO2 emissions that is rarely quantified with high-temporal-resolution data in carbon flux studies. F-soil estimates can be obtained by the low-cost gradient method (GM), but the utility of the method is hindered by uncertainties in the application of published models for the diffusion coefficient. Therefore, to address and resolve these uncertainties, we compared F-soil measured by 2 soil CO2 efflux chambers and F-soil estimated by 16 gas transport models using the GM across 1year. We used 14 published empirical gas diffusion models and 2 in situ models: (1) a gas transfer model called Chamber model obtained using a calibration between the chamber and the gradient method and (2) a diffusion model called SF6 model obtained through an interwell conservative tracer experiment. Most of the published models using the GM underestimated cumulative annual F-soil by 55% to 361%, while the Chamber model closely approximated cumulative F-soil (0.6% error). Surprisingly, the SF6 model combined with the GM underestimated F-soil by 32%. Differences between in situ models could stem from the Chamber model implicitly accounting for production of soil CO2, while the conservative tracer model does not. Therefore, we recommend using the GM only after calibration with chamber measurements to generate reliable long-term ecosystem F-soil measurements. Accurate estimates of F-soil will improve our understanding of soil respiration's contribution to ecosystem fluxes.

Ce travail s’inscrit dans le cadre de nos recherches sur les écoulements à bulles. C’est l’étude expérimentale du mélange d’un traceur très peu diffusif (fluoresceine dans l’eau) dans l’écoulement instationnaire engendré par le passage d’un écoulement uniforme au travers d’un réseau d’obstacles sphériques (2% de fraction volumique) répartis aléatoirement dans l’espace. Cet écoulement reproduit correctement les caractéristiques de l’agitation dans un essaim de bulles en ascension. La vitesse du fluide est mesurée par PIV de manière assez classique. Le traceur est injecté en amont du réseau et l’´evolution de sa concentration est mesurée par PLIF. L’utilisation de la PLIF pour mesurer des champs de grande extension (15 cm) et avec une grande dynamique d’intensité lumineuse fluorescée constitue une contribution importante de ce travail. Les résultats ainsi obtenus montrent que, à petit nombre de Reynolds, le mélange est régi par les forts gradients de vitesse qui existent dans le voisinage des sphères. A grand nombre de Reynolds, il est maîtrisé par la turbulence qui se développe alors. L’analyse des résultats comporte deux parties principales : (1) une analyse statistique des profils de concentration aboutissant à la détermination d’un coefficient de diffusion effectif et (2) une description de la distribution spectrale des fluctuations de vitesse et de concentration. / This research is a part of our research about bubbly flows. Experiments are performed about mixing of a high Schmidt scalar component (fluorescein in water) by the agitation generated by the flow through a random array of fixed spheres (at high Re and with a volume fraction of solid equal to 2%). This flow mimics for a great part the agitation in the liquid phase of a bubble swarm rising in a liquid otherwise at rest. The velocity of the liquid is estimated from PIV measurements. The scalar is injected through a point source in the array and the evolution of its concentration is estimated by PLIF method. An important part of this research is the measurement of large fields of concentration (15 cm) with a good precision by PLIF. The results show that, at moderate Reynolds number (100), mixing is controled by the steep velocity gradients located near the spheres, while, at large Reynolds number, it is controled by the turbulence that develops. The analysis of the results is composed of two parts : (1) the statistical analysis of the spatial distribution of scalar concentration, and the determination of an effective diffusion coefficient, (2) a spectral analysis of the velocity and concentration fields.