On the evolution of non-axisymmetric viscous fibres with surface tension, inertia and gravity

We consider the free boundary problem for the evolution of a nearly straight slender fibre of viscous fluid. The motion is driven by prescribing the velocity of the ends of the fibre, and the free surface evolves under the action of surface tension, inertia and gravity. The three-dimensional Navier-Stokes equations and free-surface boundary conditions are analysed asymptotically, using the fact that the inverse aspect ratio, defined to be the ratio between a typical fibre radius and the initial fibre length, is small. This first part of the paper follows earlier work on the stretching of a slender viscous fibre with negligible surface tension effects. The inclusion of surface tension seriously complicates the problem for the evolution of the shape of the cross-section. We adapt ideas applied previously to two-dimensional Stokes flow to show that the shape of the cross-section can be described by means of a conformal map which depends on time and distance along the fibre axis. We give some examples of suitable relevant maps and present numerical solutions of the resulting equations. We also use analytic methods to examine the coupling between stretching and the evolution of the cross-section shape

The effects of hypnosis on flow states and three-point shooting performance in basketball players.

This study examined the effects of hypnosis on flow states and three-point shooting performance in 5 collegiate basketball players. The investigation uti- lized an ideographic single-subject multiple baselines across subjects design combined with a procedure that monitors the internal experience of the par- ticipants (Wollman, 1986). The method of intervention utilized in this study involved relaxation, imagery, hypnotic induction, hypnotic regression, and trigger control procedures. The results indicated that all five participants in- creased both their mean basketball three-point shooting performance and their mean flow scores from baseline to intervention. There were no overlapping data points between the baseline and intervention for either performance or flow state. Additionally, each participant indicated that they had felt the inter- vention was useful in keeping them confident, relaxed, and calm. These re- sults support the hypothesis that a hypnosis intervention can improve three- point shooting performance in basketball players and increase feelings and cognitions that are associated with flow

Cultural Diversity, Discrimination and Economic Outcomes: an experimental analysis

Economists have paid increasing attention to the role of cultural diversity in explaining the variability of economic outcomes across societies. We develop an experimental framework that complements existing research in this area. We implement the framework with two cultures that coexist in an industrialized society: the Hispanic and Navajo cultures in the southwestern United States. We vary the ethnic mix of our experimental sessions in order to infer the effect of intercultural interactions on economic behavior and outcomes. We control for demographic differences in our subject pools and elicit beliefs directly in order to differentiate between statistical discrimination and preference-based discrimination. We present clear evidence that Hispanic and Navajo subjects behave differently and that their behavior is affected by the ethnic composition of the experimental session. Our experimental framework has the potential to shed much needed light on economic behavior and outcomes in societies of mixed ethnicity, race and religion.culture, diversity, discrimination, bargaining, economic experiments

SLS Processing Studies of Nylon 11 Nanocomposites

Selective Laser Sintering (SLS) is widely used for rapid prototyping/manufacturing of nylon 11 and nylon 12 parts. This processing technique has not been explored for nylon nanocomposites. This study investigates the technicalities of processing nylon 11-clay and nylon-carbon nanofiber nanocomposites with SLS. Microstructural analyses of the SLS powders and parts were conducted under SEM. Results suggest that SLS processing is possible with the new nylon 11 nanocomposites. Yet the SLS parts built have inferior properties relative to those of injection molding, suggesting that more fine tuning for the processing is required.Mechanical Engineerin

Asymptotic solutions of glass temperature profiles during steady optical fibre drawing

In this paper we derive realistic simplified models for the high-speed drawing of glass optical fibres via the downdraw method, that capture the fluid dynamics and heat transport in the fibre via conduction, convection and radiative heating. We exploit the small aspect ratio of the fibre and the relative orders of magnitude of the dimensionless parameters that characterize the heat transfer to reduce the problem to one- or two-dimensional systems via asymptotic analysis. The resulting equations may be readily solved numerically and in many cases admit exact analytic solutions. The systematic asymptotic breakdown presented is used to elucidate the relative importance of furnace temperature profile, convection, surface radiation and conduction in each portion of the furnace and the role of each in controlling the glass temperature.\ud \ud The models derived predict many of the qualitative features observed in the real industrial process, such as the glass temperature profile within the furnace and the sharp transition in fibre thickness. The models thus offer a desirable route to quick scenario testing, providing valuable practical information into the dependencies of the solution on the parameters and the dominant heat-transport mechanism