A Personal Dead Reckoning RFID Waypoint Updated System for Footstep Level Resolution Path Tracking to Enable Research Into Early Diagnosis of Alzheimer’s

The problem of footstep level resolution indoor path tracking and gait velocity lacks a good solution. The current solutions are either prohibitively expensive [4], extremely invasive to deploy [1], or too inaccurate to achieve the sub meter level resolution required to track foot paths. By combining existing pedestrian dead reckoning (PDR) using an inertial measurement unit (IMU) techniques with radio frequency identification (RFID) location updates, one can solve the problem of indoor path tracking. RFID tags placed in the building act as waypoints to correct the error that accumulates over time with PDR, thus yielding a system that can be used for arbitrary amounts of time with a resolution high enough to track individual footsteps

Investigating the influence of the core material on the mechanical performance of a nitinol wire wrapped helical auxetic yarn.

Helical Auxetic Yarns (HAYs) can be used in a variety of applications, from healthcare to blast and impact resistance. This work focuses on the effect of the use of different core materials (e.g. rubber, polyurethane, polytetrafluoroethylene/teflon, polypropylene, polyetheretherketone, polycarbonate, acetal) with a nitinol wire wrap component on the maximum Negative Poisson Ratio (NPR) produced, and therefore the auxetic performance of Helical Auxetic Yarns (HAYs). From the analytical model, it was found that an acetal core produced the largest NPR when compared to the other six materials. The trend obtained from the experimental tensile tests (validation) correlated closely with the theoretical predictions of the NPR as axial strain was increased. The experimental method presented a maximum NPR at an average axial strain of 0.148, which was close to the strain of 0.155 predicted by theory. However, the maximum experimental NPR was significantly lower than that predicted by the analytical model

Managing local coastal stressors to reduce the ecological effects of ocean acidification and warming

Anthropogenic activities have increased the number of stressors acting on ecosystems. When multiple stressors act simultaneously, there is a greater probability of additive, synergistic and antagonistic effects occurring among them. Where additive and synergistic effects occur, managers may yield disproportionately large benefits where they first act upon synergies. Stressors act, however, at different spatial and temporal scales. Global stressors (e.g., ocean acidification and warming) tend to change slowly over long periods of time, although their intensity and effects are contingent on local conditions. On the other hand, local stressors tend to change rapidly over shorter, more defined spatial and temporal scales. Hence, local stressors can be subject to a greater degree of control through local management (e.g., eutrophication and overfishing) while global stressors are characterized by an intrinsic inertia whose effects last for decades, if not centuries. Although the reduction of carbon emissions is an international priority for managing global stressors, it requires international agreements and management applications that take considerable time to develop. Managers, however, may 'buy time' by acting on stressors whose governance is local (e.g., reducing nutrient input) and are known to synergize with global stressors (e.g., enriched CO2). Such local actions may potentially disrupt synergies with the more slowly changing global stressors that can only be reduced over longer time scales. © 2013 by the authors

Phenylethynyl Terminated Imide (PETI) Composites Made by High Temperature VARTM

Fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) is generally more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications, a void fraction of <2% is desired. In the current study, two PETI resins, LARC. PETI-330 and LARC. PETI-8 have been used to fabricate test specimens using HT-VARTM. The resins were infused into carbon fiber preforms at 260 C and cured between 316 and 371 C. Photomicrographs of the panels were taken and void contents were determined by acid digestion. Modifications to the thermal cycle used in the laminate fabrication have reduced the void content significantly; typically .3% for carbon fiber biaxially woven fabric and less than 2% for carbon fiber uniaxial fabric. Mechanical properties (short beam shear and flexure) of the panels were determined at both room and elevated temperatures. The results of this work are presented herein. This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States

High Temperature VARTM of Phenylethynyl Terminated Imides (PETI) Resins

Fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) is generally more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications a void fraction of less than 2% is desired. In the current study, two PETI resins, LARCTM PETI-330 and LARCTM PETI-8 have been used to fabricate test specimens using HT-VARTM. The resins were infused into carbon fiber preforms at 260 C and cured between 316 C and 371 C. Modifications to the thermal cycle used in the laminate fabrication have reduced the void content significantly (typically < 3%) for carbon fiber biaxially woven fabric. Photomicrographs of the panels were taken and void contents were determined by acid digestion. For carbon fiber uniaxial fabric, void contents of less than 2% have been obtained using both PETI-8 and PETI-330. Mechanical properties of the panels were determined at both room and elevated temperatures. These include short beam shear and flexure tests. The results of this work are presented herein

Solid-state NMR enhanced by dynamic nuclear polarization as a novel tool for ribosome structural biology

The impact of Nuclear Magnetic Resonance (NMR) on studies of large macromolecular complexes hinges on improvements in sensitivity and resolution. Dynamic nuclear polarization (DNP) in the solid state can offer improved sensitivity, provided sample preparation is optimized to preserve spectral resolution. For a few nanomoles of intact ribosomes and an 800kDa ribosomal complex we demonstrate that the combination of DNP and magic-angle spinning NMR (MAS-NMR) allows one to overcome current sensitivity limitations so that homo- and heteronuclear 13C and 15N NMR correlation spectra can be recorded. Ribosome particles, directly pelleted and frozen into an NMR rotor, yield DNP signal enhancements on the order of ~25-fold and spectra that exhibit narrow linewidths, suitable for obtaining site-specific information. We anticipate that the same approach is applicable to other high molecular weight complexe

The responses of brown macroalgae to environmental change from local to global scales: direct versus ecologically mediated effects

In many temperate regions, brown macroalgae fulfil essential ecosystem services such as the provision of structure, the fixation of nutrients and carbon, and the production of biomass and oxygen. Their populations in many regions around the globe have declined and/or spatially shifted in recent decades. In this review we highlight the potential global and regional drives of these changes, describe the status of regionally particularly important brown macroalgal species, and describe the capacity of interactions among abiotic and biotic factors to amplify or buffer environmental pressure on brown macroalgae. We conclude with a consideration of possible management and restoration measures