Theory for solvent, momentum, and energy transfer between a surfactant solution and a vapor atmosphere

We develop a complete set of equations governing the evolution of a sharp interface separating a volatile-solvent/nonvolatile-surfactant solution from a vapor atmosphere. In addition to a sorption isotherm equation and the conventional balances for mass, linear momentum, and energy, these equations include a counterpart of the Hertz???Knudsen???Langmuir equation familiar from conventional theories of evaporation-condensation. This additional equation arises from a consideration of configurational forces within a thermodynamical framework. While the notion of configurational forces is well-developed and understood for the description of materials, like crystalline solids, that possess natural reference configurations, very little has been done regarding their role in materials, such as viscous fluids, that do not possess preferred reference states. We therefore provide a comprehensive discussion of configurational forces, the balance of configurational momentum, and configurational thermodynamics that does not require a choice of reference configuration. The general evolution equations arising from our theory account for the thermodynamic structure of the solution and the interface and for sources of dissipation related to the transport of surfactant, momentum, and heat in the solution, the transport of surfactant and momentum within the interface, and the transport of solute, momentum, kinetic energy, and heat across the interface. Due to the complexity of these equations, we provide approximate equations which we compare to relations that appear in the literature.published or submitted for publicationis peer reviewe

Patriarchal pronatalism: Islam, secularism and the conjugal confines of Turkey's IVF boom.

This article constructs an explanatory history of the introduction, growth and social regulation of IVF in Turkey, labelling it a form of 'patriarchal pronatalism'. Based on sociological research between 2006 and 2010, including analysis of regulatory and media materials as well as an in-depth clinical ethnography and interviews with IVF patients and practitioners, the paper contextualizes Turkey's 'IVF boom' within the wider and governmental contexts of reproductive politics. Examining both the legal framework and the surrounding rhetoric, it highlights how the nationally pertinent tensions between Islam and secularism unfold in this particular field, and traces how the rise of neo-conservatism and the expansion of the role of religious organizations and discourses has led to the promotion and development of assisted reproduction, but only within strictly enforced conjugal confines. This work contributes not only to the significant sociological and anthropological scholarship on the globalization, localization and repro-national character of assisted reproductive technologies around the world, but also to the growing scholarship examining the contours of reproductive citizenship, gender relations and family formation in contemporary Turkey.This paper was originally prepared for the IVF Global Histories conference at Yale University in April 2015, with support from Wellcome grant number 100606

Fertile connections? Thinking across Assisted Reproductive Technologies and Parenting Culture Studies

While studies of ‘parenting culture’ and ‘assisted reproductive technologies’ are now well-established areas of social science scholarship, so far, the potential connections between the two fields have not been significantly explored. Responding to calls for a more ‘processual’ approach to studying reproduction in order to make clearer contributions to sociological theory more broadly, we begin a dialogue between these mutually relevant bodies of literature, highlighting connections and crosscutting findings. We focus on four interlinked themes – Reflexivity, Gender, Expertise and Stratification – and promote a more holistic approach to understanding how children are conceived and cared for within the current ‘Euro-American’ reproductive landscape. By way of conclusion, we draw attention to the contemporary context of ‘anxious reproduction’ and propose directions for future research

A mathematical model for phase separation: A generalized Cahn-Hilliard equation

In this paper we present a mathematical model to describe the phenomenon of phase separation, which is modelled as space regions where an order parameter changes smoothly. The model proposed, including thermal and mixing effects, is deduced for an incompressible fluid, so the resulting differential system couples a generalized Cahn-Hilliard equation with the Navier-Stokes equation. Its consistency with the second law of thermodynamics in the classical Clausius-Duhem form is finally proved.Comment: 9 pages, 1 figure, Published online in Wiley Online Librar

On a continuum-mechanical theory for turbulence

EnWe discuss a continuum-mechanical formulation and generalization of the Navier–Stokes- equation based on a comprehensive framework for uidynamical theories with gradient dependencies (Fried & Gurtin 2006). Our ow equation entails two additional material length scales: one energetic, the other dissipative. In contrast to Lagrangian averaging, our formulation delivers boundary conditions — involving yet another length scale — and a complete structure based on thermodynamics applied to an isothermal system

Generation of interface for an Allen-Cahn equation with nonlinear diffusion

In this note, we consider a nonlinear diffusion equation with a bistable reaction term arising in population dynamics. Given a rather general initial data, we investigate its behavior for small times as the reaction coefficient tends to infinity: we prove a generation of interface property

Thermodynamics of non-local materials: extra fluxes and internal powers

The most usual formulation of the Laws of Thermodynamics turns out to be suitable for local or simple materials, while for non-local systems there are two different ways: either modify this usual formulation by introducing suitable extra fluxes or express the Laws of Thermodynamics in terms of internal powers directly, as we propose in this paper. The first choice is subject to the criticism that the vector fluxes must be introduced a posteriori in order to obtain the compatibility with the Laws of Thermodynamics. On the contrary, the formulation in terms of internal powers is more general, because it is a priori defined on the basis of the constitutive equations. Besides it allows to highlight, without ambiguity, the contribution of the internal powers in the variation of the thermodynamic potentials. Finally, in this paper, we consider some examples of non-local materials and derive the proper expressions of their internal powers from the power balance laws.Comment: 16 pages, in press on Continuum Mechanics and Thermodynamic