Wearable Computing: Interface, Emotions and the Wearer\u27s Culture

Wearable computing offers an interesting subset for the mobile computing field. While Google Glass might not yet have found the mass audience it sought, other, simpler, wearable devices have made an impact. This paper presents results of a four-week long experiment in how subjects interact and emotionally respond to the Fitbit Flex. Users tracked daily totals of steps, distance traveled, minutes active, calories burned, and time slept. They also found their own personal uses for the Fitbit interface. Users were asked to be aware of and report their emotional reactions by keeping continuous, daily journals. A popular and relatively inexpensive mobile device offered an opportunity to study an interface used with regularity over a defined and sustained time period. The interface and the user interacted; the device\u27s constant presence had the potential to bind it to the wearer’s emotional life. The wearable device prompted and reinforced emotions already present in the culture in which the users were immersed. There was also agreement among participants that the device altered users\u27 behaviors

Gravity-driven instability in a spherical Hele-Shaw cell

A pair of concentric spheres separated by a small gap form a spherical Hele-Shaw cell. In this cell an interfacial instability arises when two immiscible fluids flow. We derive the equation of motion for the interface perturbation amplitudes, including both pressure and gravity drivings, using a mode coupling approach. Linear stability analysis shows that mode growth rates depend upon interface perimeter and gravitational force. Mode coupling analysis reveals the formation of fingering structures presenting a tendency toward finger tip-sharpening.Comment: 13 pages, 4 ps figures, RevTex, to appear in Physical Review

Mode-coupling approach to non-Newtonian Hele-Shaw flow

The Saffman-Taylor viscous fingering problem is investigated for the displacement of a non-Newtonian fluid by a Newtonian one in a radial Hele-Shaw cell. We execute a mode-coupling approach to the problem and examine the morphology of the fluid-fluid interface in the weak shear limit. A differential equation describing the early nonlinear evolution of the interface modes is derived in detail. Owing to vorticity arising from our modified Darcy's law, we introduce a vector potential for the velocity in contrast to the conventional scalar potential. Our analytical results address how mode-coupling dynamics relates to tip-splitting and side branching in both shear thinning and shear thickening cases. The development of non-Newtonian interfacial patterns in rectangular Hele-Shaw cells is also analyzed.Comment: 14 pages, 5 ps figures, Revtex4, accepted for publication in Phys. Rev.

Quasiperiodic Tip Splitting in Directional Solidification

We report experimental results on the tip splitting dynamics of seaweed growth in directional solidification of succinonitrile alloys with poly(ethylene oxide) or acetone as solutes. The seaweed or dense branching morphology was selected by solidifying grains which are oriented close to the {111} plane. Despite the random appearance of the growth, a quasiperiodic tip splitting morphology was observed in which the tip alternately splits to the left and to the right. The tip splitting frequency f was found to be related to the growth velocity V as a power law f V^{1.5}. This finding is consistent with the predictions of a tip splitting model that is also presented. Small anisotropies are shown to lead to different kinds of seaweed morphologies.Comment: 4 pages, 7 figures, submitted to Physical Review Letter

Control of rotorcraft retreating blade stall using air-jet vortex generators

A series of low-speed wind tunnel tests were carried out on an oscillating airfoil fitted with two rows of air-jet vortex generators (AJVGs). The airfoil used had an RAE 9645 section and the two spanwise arrays of AJVGs were located at x/c=0.12 and 0.62. The devices and their distribution were chosen to assess their ability to modify/control dynamic stall; the goal being to enhance the aerodynamic performance of helicopter rotors on the retreating blade side of the disc. The model was pitched about the quarter chord with a reduced frequency (k) of 0.1 in a sinusoidal motion defined by a=15o+10sin_ t. The measured data indicate that, for continuous blowing from the front row of AJVGs with a momentum blowing coefficient (C μ) greater than 0.008, modifications to the stalling process are encouraging. In particular, the pitching moment behavior exhibits delayed stall and there is a marked reduction in the normal force hysteresis

Superhero comics and the digital communications circuit: a case study of <i>Strong Female Protagonist</i>

This article examines the ongoing superhero webcomic Strong Female Protagonist (2012-present), by Brannon Lee Mulligan and Molly Ostertag and employs it as a case study to analyse the new communications circuit created by the digital production and delivery of comics. It adopts a perspective drawn from Book History to frame the communication model of print comics and to evaluate how webcomics such as Strong Female Protagonist redefine the role of readers, authors and publishers

The Saffman-Taylor problem on a sphere

The Saffman-Taylor problem addresses the morphological instability of an interface separating two immiscible, viscous fluids when they move in a narrow gap between two flat parallel plates (Hele-Shaw cell). In this work, we extend the classic Saffman-Taylor situation, by considering the flow between two curved, closely spaced, concentric spheres (spherical Hele-Shaw cell). We derive the mode-coupling differential equation for the interface perturbation amplitudes and study both linear and nonlinear flow regimes. The effect of the spherical cell (positive) spatial curvature on the shape of the interfacial patterns is investigated. We show that stability properties of the fluid-fluid interface are sensitive to the curvature of the surface. In particular, it is found that positive spatial curvature inhibits finger tip-splitting. Hele-Shaw flow on weakly negative, curved surfaces is briefly discussed.Comment: 26 pages, 4 figures, RevTex, accepted for publication in Phys. Rev.

Microscopic Selection of Fluid Fingering Pattern

We study the issue of the selection of viscous fingering patterns in the limit of small surface tension. Through detailed simulations of anisotropic fingering, we demonstrate conclusively that no selection independent of the small-scale cutoff (macroscopic selection) occurs in this system. Rather, the small-scale cutoff completely controls the pattern, even on short time scales, in accord with the theory of microscopic solvability. We demonstrate that ordered patterns are dynamically selected only for not too small surface tensions. For extremely small surface tensions, the system exhibits chaotic behavior and no regular pattern is realized.Comment: 6 pages, 5 figure

Psychosocial Interventions to Reduce Compulsory Psychiatric Admissions: A Rapid Evidence Synthesis

Background Compulsory mental health hospital admissions are increasing in several European countries but are coercive and potentially distressing. It is important to identify which mental health service models and interventions are effective in reducing compulsory admissions. Methods We conducted a rapid evidence synthesis to explore whether there is any evidence for an effect on compulsory admissions for 15 types of psychosocial intervention, identified by an expert group as potentially relevant to reducing compulsory admission. A search for randomised controlled trials (RCTs) reporting compulsory admission as a primary or secondary outcome or adverse event was carried out using clinical guidelines, recent systematic reviews, and database searches postdating these reviews. Findings We found 949 RCTs reporting on the interventions of interest, of which 19 reported on compulsory admission. Our narrative synthesis found some evidence for the effectiveness of crisis planning and self-management, while evidence for early intervention services was mixed. We did not find evidence to support adherence therapy, care from crisis resolution teams and assertive community treatment, but numbers of relevant studies were very small. We found no trials which tested effects on compulsory admission of the nine other intervention types. Interpretation Crisis planning and self-management interventions with a relapse prevention element are most promising for preventing compulsory admissions. Given our broad search strategy, the lack of evidence demonstrates that there is an urgent need for more research on interventions which may reduce compulsory admissions