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Dissertação (Mestrado em Engenharia Mecânica) - Centro Universitário FEI, São Bernardo do Campo, 2018

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Poly(N-isopropylacrylamide) (PNIPAM) belongs to a class of stimuli-responsive materials known as “smart” polymers. When cast in the form of a hydrogel, PNIPAM’s lower critical solution temperature (LCST) of 32°C serves as a threshold for volumetric change. For solution temperatures below LCST, PNIPAM hydrogels exist as swollen, hydrophilic networks of polymer and water, spontaneously expelling the bound water molecules to shrink (and become increasingly hydrophobic) as temperature increases beyond LCST. This thesis centers on PNIPAM hydrogel layers grafted along the inner diameter of glass capillaries in order to form a temperature-responsive gating mechanism that spontaneously seals for solution temperatures below LCST. Surprisingly, very thin layers (10-20µm) of PNIPAM have dramatic effects on bulk fluid flow through the capillary due to complex interactions at the swelling interface. Specifically, for the case of capillary pressure driven flow, the swelling PNIPAM interface gives rise to "stick-and-slip" motion for bulk flow. Experiments explore the extent of this phenomenon, while a theoretical framework is proposed to model how the evolving gel interface pins the contact line. Additionally, an exploratory segment of this work examines the ways in which PNIPAM hydrogel nanoarrays can be synthesized via scalable template methods. Nanostructured PNIPAM films exhibit dramatic changes in surface properties with temperature, characterized by very low contact angles (~10°) below LCST, and very high ones (~160°) above LCST. Results for several methods are presented with lessons learned to guide future development of surfaces with temperature-responsive wetting properties.

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Slavoj Zizek is a contemporary political philosopher widely recognized for his aphoristic style. Contrary to many forms of more traditional theory, Zizek does not forward his arguments as a series of well-argued, logically flowing propositions, but rather as a cacophony of diagnoses running the gamut of social science and culture studies while nevertheless always slipping from one position to another, occupying at times the position of the orthodox Marxist in the face of post-modernism’s excesses, and at other times doing quite the opposite. This study proposes a reading methodology that takes aphorism and hyperbole as key elements of writing; more specifically, this study understands writing as a political intervention, and reads Zizek’s recent works in this light. Arguing that Zizek occupies a multitude of positions against a multitude of interlocutors on the post-Marxist scene, this thesis claims that it is precisely his ability to navigate between two distinct scenes which constitutes his novelty. Zizek combats conventional forms of leftism in order to open up a space for a new theoretical position, denying the coordinates of both post-Marxism and postmodernism.

Slavoj Zizek is a contemporary political philosopher widely recognized for his aphoristic style. Contrary to many forms of more traditional theory, Zizek does not forward his arguments as a series of well-argued, logically flowing propositions, but rather as a cacophony of diagnoses running the gamut of social science and culture studies while nevertheless always slipping from one position to another, occupying at times the position of the orthodox Marxist in the face of post-modernism’s excesses, and at other times doing quite the opposite. This study proposes a reading methodology that takes aphorism and hyperbole as key elements of writing; more specifically, this study understands writing as a political intervention, and reads Zizek’s recent works in this light. Arguing that Zizek occupies a multitude of positions against a multitude of interlocutors on the post-Marxist scene, this thesis claims that it is precisely his ability to navigate between two distinct scenes which constitutes his novelty. Zizek combats conventional forms of leftism in order to open up a space for a new theoretical position, denying the coordinates of both post-Marxism and postmodernism.

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AN ABSTRACT OF THE THESIS OF Jacob Boone, for the Master of Science degree in Mechanical Engineering, presented on 10/28/2010, at Southern Illinois University Carbondale. TITLE: DESIGN, CONSTRUCTION, AND EVALUTAION OF UNIVERSAL FRICTION TESTER MAJOR PROFESSOR: Dr. Peter Filip Many different types of friction testers are currently available for testing specific frictional applications. Of these machines very few have versatility, and of the ones that do, the amount of versatility is limited. Since friction is a property specific to each system, all operating parameters need to match the specific application as closely as possible in order to obtain accurate data. This requires many research facilities to have several specific friction testers in order to provide the necessary testing capabilities. The goal of this project was to design a Universal Friction Tester (UFT) with enough versatility to reproduce most types of sliding friction situations. This was accomplished by providing a wide range of testing capabilities through the use of interchangeable system components. Results show that the UFT provides quality data over its entire operating range. It was shown that normal pressure, sliding speed, temperature and system stiffness all have drastic effects on frictional performance. By using a borosilicate glass disc, the friction surface was viewed in-situ during testing. This allowed insights into true surface temperature and contact area. In conclusion, the UFT can successfully take the place of several friction testers and thus provide many friction research capabilities while requiring fewer resources. The wide range of testing capabilities will allow the UFT to be used as a research tool for many types of advanced friction studies. Some of these may include true surface temperatures, true contact area, influence of conditions on stick-slip phenomenon, and thermo-elastic instabilities.