Evaluation of Superpave mixtures in West Virginia using the asphalt pavement analyzer

The Superpave mix design method is widely implemented in the Unites States. Fundamental tests have been developed to assess a pavement\u27s distress; however, those tests are time-consuming and require special equipment. Simpler tests, such as wheel tracking devices, have been developed. The most common is the Asphalt Pavement Analyzer, APA, a loaded wheel tester method to evaluate rutting, moisture susceptibility, and fatigue cracking.;This research focused on establishing whether there are relationships between the APA rutting potential and field performance. The APA was used to measure the rutting potential of Superpave mixes constructed throughout the state. Then the WVDOH provided rutting data from their pavement condition database. Comparison between the laboratory rutting potential and the field results was established. The APA test results indicate the Superpave mixes used in the state are not rut susceptible. The field data verifies that pavements constructed with Superpave mixes are not rutting

Sudden Critical Current Drops Induced in S/F Structures

In the search for new physical properties of S/F structures, we have found that the superconductor critical current can be controlled by the domain state of the neighboring ferromagnet. The superconductor is a thin wire of thickness d_{s} ~ 2 xi_{S}. Nb/Co and Nb/Py (Permalloy Ni_{80}Fe_{20}) bilayer structures were grown with a significant magnetic anisotropy. Critical current measurements of Nb/Co structures with ferromagnet thickness d_{F} > 30nm show sudden drops in two very defined steps when the measurements are made along the hard axes direction (i.e. current track parallel to hard anisotropy axes direction). These drops disappear when they are made along the easy axis direction or when the ferromagnet thickness is below 30nm. The drops are accompanied by vortex flux flow. In addition magnetorestistance measurements close to Tc show a sharp increase near saturation fields of the ferromagnet. Similar results are reproduced in Nb/Py bilayer structure with the ferromagnet thickness d_{F} ~ 50nm along the easy anisotropy axes. These results are explained as being due to spontaneous vortex formation and flow induced by Bloch domain walls of the ferromagnet underneath. We argue these Bloch domain walls produce a 2D vortex-antivortex lattice structure.Comment: 6 pages, 6 figure

Light Produces Calcium Waves in Nature

Calcium waves that arise from high intensity 405nm blue light photostimulation in Arabidopsis thaliana have been observed and studied in the Griffing Laboratory to identify photoreceptors and signaling significance. This project attempts to understand when and if this high-intensity 405nm light occurs in nature by analyzing the parameters that lead to high-intensity light in real-life conditions. Our model is that the light not only has to be of a specific wavelength and photon dose, but it also needs to shine on a specific subcellular region, the ER-chloroplast nexus, to get direct stimulation and produce the calcium wave. This research measures photon dose and wavelength required for photostimulation with a microscope-based spectrometer and power meter and whether dew drops or rain drops might focus the light to a subcellular location. It also explores the varied factors that may affect the interaction of light with plant cells to create the photostimulation effect. Experiments analyze the threshold at which photostimulation triggers signaling and correlate these experiments to how sunlight could also trigger signaling in real-life conditions. Other experiments explore the effect of a circadian rhythm in the respective calcium wave. Connections between the observed wavelengths under weather conditions and how the presence of drops increase the power of light support our hypothesis. Structures such as trichomes can also influence the focal point of the light in the plant surface and direct it to the ER-chloroplast nexus at the optimal power to create the calcium wave

Quantifying slumness with remote sensing data

The presence of slums in a city is an indicator of poverty and its proper delimitation is a matter of interest for researchers and policy makers. Socio-economic data from surveys and censuses are the primary source of information to identify and quantify slumness within a city or a town. One problem of using survey data for quantifying slumness is that this type of data is usually collected every ten years and is an expensive and time consuming process. Based on the premise that the physical appearance of an urban settlement is a reflection of the society that created it and on the assumption that people living in urban areas with similar physical housing conditions will have similar social and demographic characteristics (Jain, 2008; Taubenb¨ock et al., 2009b); this paper uses data from Medellin City, Colombia, to estimate slum index using solely remote sensing data from an orthorectified, pan-sharpened, natural color Quickbird scene. For Medellin city, the percentage of clay roofs cover and the mean swimming pool density at the analytical region level can explain up to 59% of the variability in the slum index. Structure and texture measures are useful to characterize the differences in the homogeneity of the spatial pattern of the urban layout and they improve the explanatory power of the statistical models when taken into account. When no other information is used, they can explain up to 30% of the variability of the slum index. The results of this research are encouraging and many researchers, urban planners and policy makers could benefit from this rapid and low cost approach to characterize the intra-urban variations of slumness in cities with sparse data or no data at all

A Common Software Configuration Management System for CERN SPS and LEP Accelerators and Technical Services

Software configuration management activities are crucial to assure the integrity of current operational and the quality of new software either being developed at CERN or outsourced. The functionality of the present management system became insufficient with large maintenance overheads. In order to improve our situation, a new software configuration management system has been set up. It is based on Razor, a commercial tool, which supports the management of file versions and operational software releases, along with integrated problem reporting capabilities. In addition to the basic tool functionality, automated procedures were custom made, for the installation and distribution of operational software. Policies were developed and applied over the software development life cycle to provide visibility and control. The system ensures that, at all times, the status and location of all deliverable versions are known, the state of shared objects is carefully controlled and unauthorised changes prevented. It provides a managed environment for software development, in various domains of the SPS and LEP CERN accelerators, and the technical services, automating code and lifecycle management. This paper outlines the reasons for selecting the chosen tool, the implementation of the system, the problems solved and the final goals achieved

Real-Time Hybrid Simulation for Infrastructure Degradation Assessment: Conceptual Framework and Illustrative Application

To date, the prospect of using real-time hybrid simulation (RTHS) to study the effects of long-term or 'wear-and-tear' loads, such as exposure to harmful environmental conditions or fatigue, has remained underexplored. This study presents a conceptual framework to assess the impact of long-term degradation on infrastructure systems. The framework integrates the capabilities of RTHS with accelerated degradation techniques to evaluate the behavior of a degrading system over time. Experimental results obtained in this way not only capture the complex interactions but also provide a reliability-based method to determine the expected time-to-failure of the evaluated system. The developed framework is demonstrated using a virtual RTHS platform designed to test fiber-reinforced elastomeric isolators.Comment: 5 pages, 4 figure

Within-individual variation of trunk and branch xylem density in tropical trees

Premise of the study: Wood density correlates with mechanical and physiological strategies of trees and is important for estimating global carbon stocks. Nonetheless, the relationship between branch and trunk xylem density has been poorly explored in neotropical trees. Here, we examine this relationship in trees from French Guiana and its variation among different families and sites, to improve the understanding of wood density in neotropical forests. Methods: Trunk and branch xylem densities were measured for 1909 trees in seven sites across French Guiana. A major-axis fit was performed to explore their general allometric relationship and its variation among different families and sites. Key results: Trunk xylem and branch xylem densities were significantly positively correlated, and their relationship explained 47% of the total variance. Trunk xylem was on average 9% denser than branch xylem. Family-level differences and interactions between family and site accounted for more than 40% of the total variance, whereas differences among sites explained little variation. Conclusions: Variation in xylem density within individual trees can be substantial, and the relationship between branch xylem and trunk xylem densities varies considerably among families and sites. As such, whole-tree biomass estimates based on non- destructive branch sampling should correct for both taxonomic and environmental factors. Furthermore, detailed estimates of the vertical distribution of wood density within individual trees are needed to determine the extent to which relying solely upon measures of trunk wood density may cause carbon stocks in tropical forests to be overestimated