Morphology and the gradient of a symmetric potential predicts gait transitions of dogs

Gaits and gait transitions play a central role in the movement of animals. Symmetry is thought to govern the structure of the nervous system, and constrain the limb motions of quadrupeds. We quantify the symmetry of dog gaits with respect to combinations of bilateral, fore-aft, and spatio-temporal symmetry groups. We tested the ability of symmetries to model motion capture data of dogs walking, trotting and transitioning between those gaits. Fully symmetric models performed comparably to asymmetric with only a 22% increase in the residual sum of squares and only one-quarter of the parameters. This required adding a spatio-temporal shift representing a lag between fore and hind limbs. Without this shift, the symmetric model residual sum of squares was 1700% larger. This shift is related to (linear regression, n = 5, p = 0.0328) dog morphology. That this symmetry is respected throughout the gaits and transitions indicates that it generalizes outside a single gait. We propose that relative phasing of limb motions can be described by an interaction potential with a symmetric structure. This approach can be extended to the study of interaction of neurodynamic and kinematic variables, providing a system-level model that couples neuronal central pattern generator networks and mechanical models

Experimental determination of the state-dependent enhancement of the electron-positron momentum density in solids

The state-dependence of the enhancement of the electron-positron momentum density is investigated for some transition and simple metals (Cr, V, Ag and Al). Quantitative comparison with linearized muffin-tin orbital calculations of the corresponding quantity in the first Brillouin zone is shown to yield a measurement of the enhancement of the s, p and d states, independent of any parameterizations in terms of the electron density local to the positron. An empirical correction that can be applied to a first-principles state-dependent model is proposed that reproduces the measured state-dependence very well, yielding a general, predictive model for the enhancement of the momentum distribution of positron annihilation measurements, including those of angular correlation and coincidence Doppler broadening techniques

An Update of NASA Public Health Applications Projects using Remote Sensing Data

Satellite earth observations present a unique vantage point of the earth s environment from space which offers a wealth of health applications for the imaginative investigator. The session will present research results of the remote sensing environmental observations of earth and health applications. This session will an overview of many of the NASA public health applications using Remote Sensing Data and will also discuss opportunities to become a research collaborator with NASA

Anion receptor chemistry: highlights from 2011 and 2012

This review covers advances in anion complexation in the years 2011 and 2012. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as self-assembly and molecular architecture, sensing, catalysis and anion transport

Effect of specimen geometry and aps flash bond coating on TBC lifetime

Thermal barrier coatings (TBCs) for land-based gas turbines are primarily thermally sprayed and are unlikely to contain precious metals. For regions of the world where natural gas prices are high, turbine efficiency is a critical issue, however, durability and reliability also are very important for large scale generation. Seeking pathways for improved performance and lifetime model development, a variety of TBC performance parameters have been investigated over the years using furnace cycle testing, including bond coating composition, substrate composition, cycle frequency and environment (i.e. additions of H2O, CO2, etc.). The baseline system has been superalloy 247 substrates with high velocity oxygen fuel (HVOF) NiCoCrAlYHfSi bond coatings and air plasma sprayed yttria-stabilized zirconia (YSZ) top coatings tested in “wet” air (10%H2O) at 900°-1150°C. Recently, specimen geometry was changed from flat disks to rods. Using similar coating parameters, FCT lifetime in 100-h cycles at 1100°C in air with 10%H2O dropped by ~5X for rods compared to disks. Coating architectures that were developed for flat disk specimens did not appear to be effective in improving lifetime in FCT for rod specimens. The addition of an APS “flash” coating resulted in a significant increase in FCT lifetime in rod specimens. The benefit of this additional bond coating layer has generally thought to be due to increased interface roughness compared to a conventional HVOF coating. The most recent testing has returned to 1-h FCT of disk specimens using ~50µm APS flash coatings of both NiCoCrAlYHfSi and NiCoCrAlY flash coatings deposited on HVOF NiCoCrAlYHfSi. A similar set of rod specimens also is being evaluated in 100-h cycles. Both tests are being conducted at 1100°C in air with 10%H2O. Both flash coatings show a statistically significant increase in FCT TBC lifetime in 1-h cycles. Surprisingly, the Y only flash coating has significantly outperformed the YHfSi flash coating with some work still in progress. Residual stress in the thermally grown alumina scale has been tracked every 100 1-h cycles and 5, 100-h cycles for one sample of each coating type to quantify the evolution of the reaction product and better understand the FCT results. Failed specimens are being characterized to better understand the benefit of flash coatings on TBC lifetime. Research was sponsored by the U. S. Department of Energy, Office of Fossil Energy, Turbine Program

Highly effective yet simple transmembrane anion transporters based upon ortho-phenylenediamine bis-ureas

Simple, highly fluorinated receptors are shown to function as highly effective transmembrane anion antiporters with the most active transporters rivalling the transport efficacy of natural anion transporter prodigiosin for bicarbonate