Bubble Growth From First Principals

We consider the simplest relevant problem in the foaming of molten plastics, the growth of a single bubble in a sea of highly viscous Newtonian fluid, and without interference from other bubbles. This simplest problem has defied accurate solution from first principles. Despite plenty of research on foaming, classical approaches from first principles have neglected the temperature rise in the surrounding fluid, and we find that this oversimplification greatly accelerates bubble growth prediction. We use a transport phenomena approach to analyze the growth of a solitary bubble, expanding under its own pressure. We consider a bubble of ideal gas growing without the accelerating contribution from mass transfer into the bubble. We explore the roles of viscous forces, fluid inertia, and viscous dissipation. We find that bubble growth depends upon the nucleus radius and nucleus pressure. We begin with a detailed examination of the classical approaches (thermodynamics without viscous heating). Our failure to fit experimental data with these classical approaches, sets up the second part of our paper, a novel exploration of the essential decelerating role of viscous heating. We explore both isothermal and adiabatic bubble expansion, and also the decelerating role of surface tension. The adiabatic analysis accounts for the slight deceleration due to the cooling of the expanding gas, which depends on gas polyatomicity. We also explore the pressure profile, and the components of the extra stress tensor, in the fluid surrounding the growing bubble. These stresses can eventually be frozen into foamed plastics. We find that our new theory compares well with measured bubble behavior.

WAKING (TO) THINKING BEING: A STUDY OF EDUCATION, METAPHYSICS, MIND, AND LANGUAGE

This dissertation articulates the basic aims and achievements of education. It recognizes language as central to thinking, and philosophy and education as belonging profoundly to one another. The first step is to show that although philosophy can no longer claim to dictate the foundations of knowledge or of disciplines of inquiry, it still offers an exceptionally general level of self-understanding. Education is equally general and faces a similar crisis of self-identity, of coming to terms with reality. Language is the medium of thought and the repository of historical mind; so a child’s acquisition of language is her acquisition of rational freedom. This marks a metaphysical change: no longer merely an animal, she comes to exercise her powers of rationality, transcending her environment by seeking and expressing reasons for thinking and doing. She can think about herself in relation to the universe, hence philosophize and educate others in turn. The discussion then turns to the historical nature of language. The thinking already embedded in language always anticipates further questioning. Etymology serves as a model for philosophical understanding, and demonstrates how philosophy can continue to yield insights that are fundamental, but not foundational, to human life. The etymologies of some basic educational concepts disclose education as a leading out and into the midst of Being. The philosophical approach developed in previous chapters applies to the very idea of an educational aim. Discussion concerning the substantiality of educational ideals results in an impasse: one side recommends an open-­ended understanding of education’s aims; the other insists on a definitive account. However, educational ideals exhibit a conceptual duality: the fundamental achievements of education, such as rational freedom, are real; but how we should understand them remains an open question. The penultimate chapter investigates philosophical thinking as the fulfillment of rational freedom, whose creative insights can profoundly transform our everyday activities. That this transformative self-understanding is without end suggests the basic aims of education are unheimlich. The dissertation concludes with speculative reflection on the shape and nature of language, and with the suggestion that through education reality awakens to itself.

Crises of In/Humanity: Posthumanism, Afrofuturism, and Science and/as Fiction

This thesis engages black critical thought on the human and its contemporary iterations in posthumanism and transhumanism. It articulates five categories of analysis: displace, interrupt, disrupt, expand, and wither. Each is meant to allude to the generative potential in different iterations of black thought that engages the human. Working through Sylvia Wynter’s theories of the rise of Man-as-human in particular, the project highlights how black thought on the human displaces the uncritical whiteness of posthumanist thought. It argues that Afrofuturism has the potential to interrupt the linear progression from human to posthuman and that Octavia Butler’s Fledgling proffers a narrative of race as a technology that disrupts the presumed post-raciality of posthumanism and transhumanism. It then contends that Katherine McKittrick’s rearticulation of the Promise of Science can be extended to incorporate the promise of science fiction. In so doing, it avers that a more curated conversation between McKittrick and Wynter, one already ongoing, and Octavia Butler, through Mind of My Mind from her Patternist series, expands our notions of the human as a category even at the risk of seeing it wither as a politic or praxis. It ends on a speculative note meant to imagine the possibilities within the promise of science fiction.