FOOT ARCH STRAIN OF EXCESSIVE PRONATORS DURING TWO-LEGS AND ONELEG STANDING AND WALKING

INTRODUCTION: The movement of plantar fascia under the foot has been characterized by foot arch strain in vitro (Kogler, Solomonidis, & Paul, 1995). The characteristics of the foot arch strain under the static and dynamic conditions in excessive pronators are not well known. Therefore, the purpose of this study is to investigate the foot arch strain during two legs, one-leg standing and walking in excessive pronation

Oxygen Adsorption on Au–Ni(111) Surface Alloys

Molecular O[subscript 2] dissociates upon interaction with a Ni(111) surface, as the spatial and energetic overlap between the Ni 3d electrons and the O[subscript 2] antibonding orbitals is quite favorable. On a Au–Ni(111) surface alloy where the extent of this overlap is greatly reduced, exposure to O[subscript 2] results in adsorption of molecular O[subscript 2] characterized by three peroxo- or superoxo-like vibrational bands centered at 743, 856, and 957 cm[superscript –1] as observed by high resolution electron energy loss spectroscopy. These bands correspond to the stretch vibrational mode of O[subscript 2] at respective adsorption sites of type pseudo-3-fold fcc/hcp, degenerate-pseudo-2-fold fcc/hcp and bridge, and pseudo-3-fold bridge. These unusual chemical environments are brought about by surface alloying, rather than the presence of Au clusters on Ni, and are further stabilized by a dramatic reconstruction of the top two surface layers, as explained with an idealized surface alloy model in conjunction with electronic structure considerations. The ability to adjust the relative populations of the different oxygen cohorts by varying the Au content suggests the utility of surface alloy motifs for engineering applications.United States. Dept. of Energy (DE-FG02-05ER15665)Shell-MITEI Seed Fund Progra

Bright color optical switching device by polymer network liquid crystal with a specular reflector

The color optical switching device by polymer network liquid crystal (PNLC) with color filter on a specular reflector shows excellent performance; white reflectance of 22%, color gamut of 32%, and contrast ratio up to 50:1 in reflective mode measurement. The view-angle dependence of the reflectance can be adjusted by changing the PNLC thickness. The color chromaticity shown by the device is close to the limit value of color filters, and its value nearly remains with respect to the operating voltage. These optical properties of the device can be explained from the prediction based on multiple interactions between the light and the droplets of liquid crystal. The high reflectance, vivid color image, and moderate responds time allow the PNLC device to drive good color moving image. It can widely extend the applications of the reflective device. © 2011 Optical Society of America.1

A Passivity-based Nonlinear Admittance Control with Application to Powered Upper-limb Control under Unknown Environmental Interactions

This paper presents an admittance controller based on the passivity theory for a powered upper-limb exoskeleton robot which is governed by the nonlinear equation of motion. Passivity allows us to include a human operator and environmental interaction in the control loop. The robot interacts with the human operator via F/T sensor and interacts with the environment mainly via end-effectors. Although the environmental interaction cannot be detected by any sensors (hence unknown), passivity allows us to have natural interaction. An analysis shows that the behavior of the actual system mimics that of a nominal model as the control gain goes to infinity, which implies that the proposed approach is an admittance controller. However, because the control gain cannot grow infinitely in practice, the performance limitation according to the achievable control gain is also analyzed. The result of this analysis indicates that the performance in the sense of infinite norm increases linearly with the control gain. In the experiments, the proposed properties were verified using 1 degree-of-freedom testbench, and an actual powered upper-limb exoskeleton was used to lift and maneuver the unknown payload.Comment: Accepted in IEEE/ASME Transactions on Mechatronics (T-MECH