Performance of Warranted Asphalt Pavements: Smoothness and Performance of Indiana Warranted Asphalt Pavements

In the early 1990s the Indiana Department of Transportation (INDOT) developed a five-year warranty specification for asphalt pavements with the first project being built in 1996. In 2004, results indicated that the asphalt pavements built with the warranty specification had improved performance over the conventional asphalt pavements. Nineteen years have passed since the original asphalt pavement warranty project was placed in Indiana. It has been eleven years since the performance of the warranted asphalt pavements has been analyzed to determine the effectiveness of warranties. Therefore, it is prudent to reexamine the potential benefits of asphalt pavement warranties. Hence, the ultimate goal of the project is to advise the INDOT on whether the use of asphalt pavement warranties has potential benefit for lowering the cost of ownership for asphalt paved roadways. Overall, performance comparisons of Indiana’s warranted and non-warranted asphalt pavements indicate that warranted asphalt pavements tend to perform more effectively than do non-warranted asphalt pavements. On average, warranted asphalt pavement sections had lower IRI values and rut depths than did non-warranted sections. The variability in IRI values and rut depths was also found to be less for warranted pavement sections than for the non-warranted sections. In terms of service life based on changes in IRI and rut depth, analyses indicate that warranted asphalt pavements could last 10 to 14 years longer than non-warranted asphalt pavements. When both initial capital costs and maintenance expenditures are considered, warranted asphalt pavements appear to be 15 to 40% more cost effective over a 5-year (short-term) period and 47 to 61% more cost effective over a 15-year (long-term) period. These savings do not include potential benefits of reduced user costs nor reduced INDOT inspection costs

Theory of imaging a photonic crystal with transmission near-field optical microscopy

While near-field scanning optical microscopy (NSOM) can provide optical images with resolution much better than the diffraction limit, analysis and interpretation of these images is often difficult. We present a theory of imaging with transmission NSOM that includes the effects of tip field, tip/sample coupling, light propagation through the sample and light collection. We apply this theory to analyze experimental NSOM images of a nanochannel glass (NCG) array obtained in transmission mode. The NCG is a triangular array of dielectric rods in a dielectric glass matrix with a two-dimensional photonic band structure. We determine the modes for the NCG photonic crystal and simulate the observed data. The calculations show large contrast at low numerical aperture (NA) of the collection optics and detailed structure at high NA consistent with the observed images. We present calculations as a function of NA to identify how the NCG photonic modes contribute to and determine the spatial structure in these images. Calculations are presented as a function of tip/sample position, sample index contrast and geometry, and aperture size to identify the factors that determine image formation with transmission NSOM in this experiment.Comment: 28 pages of ReVTex, 14 ps figures, submitted to Phys. Rev.

Heating due to momentum transfer in low-energy positronium-antiproton scattering

Discovery that the elastic scattering cross sections in the antiproton-positronium system are very large close to threshold, particularly for excited positronium states.The implications for experiments aiming to use the positronium-antiproton system for antihydrogen formation are explored

Optimizing Laboratory Mixture Design as It Relates to Field Compaction to Improve Asphalt Mixture Durability

Most departments of transportation, including Indiana, currently use the Superpave mixture design method to design asphalt mixtures. This method specifies that the optimum asphalt content for a given gradation be selected at 4 percent air voids. During construction, these mixtures are typically compacted to 7-8 percent air voids. If mixtures were designed to be more compactable in the field they could be compacted to the same density as the laboratory mixture design, which would increase pavement durability by decreasing the in-place air voids. The objective of this research was to optimize the asphalt mixture design in order to increase in-place asphalt pavement durability without sacrificing the permanent deformation characteristics of the mixture. Three asphalt mixtures were designed using the standard Superpave design method at 100 gyrations of the Superpave Gyratory Compactor, suitable for traffic levels of 3 to 30 million Equivalent Single Axle Loads. Each mixture was then used as a starting point to design three additional mixtures using 70, 50, and 30 gyrations, with optimum binder content chosen at 5 percent air voids, rather than the currently specified 4 percent. The effective asphalt content was held constant for the original and redesigned mixtures. Permanent deformation characteristics of the sets of four mixtures were determined by measuring the dynamic modulus and flow number. The results suggest that the mixture designs produced using 70, 50, and 30 gyrations had permanent deformation characteristics equal to or better than the original 100-gyration mixtures. Based on the laboratory test results, two field trials were placed evaluate the design method, ease of construction and to compare the construction results of the re-designed and original mixtures. Samples from both projects were collected during construction, test specimens compacted, and additional physical testing completed. The field trial results suggest that it is possible to place a mixture at 5 percent air voids and that mixtures designed at 5 percent air voids should have equivalent performance to those designed at the conventional 4 percent air voids

Fluorescence Imaging of Underexpanded Jets and Comparison with CFD

An experimental study of underexpanded and highly underexpanded axisymmetric nitrogen free jets seeded with 0.5% nitric oxide (NO) and issuing from a sonic orifice was conducted at NASA Langley Research Center. Reynolds numbers based on nozzle exit conditions ranged from 770 to 35,700, and nozzle exit-to-ambient jet pressure ratios ranged from 2 to 35. These flows were non-intrusively visualized with a spatial resolution of approximately 0.14 mm x 0.14 mm x 1 mm thick and a temporal resolution of 1 s using planar laser-induced fluorescence (PLIF) of NO, with the laser tuned to the strongly-fluorescing UV absorption bands of the Q1 band head near 226.256 nm. Three laminar cases were selected for comparison with computational fluid dynamics (CFD). The cases were run using GASP (General Aerodynamic Simulation Program) Version 4. Comparisons of the fundamental wavelength of the jet flow showed good agreement between CFD and experiment for all three test cases, while comparisons of Mach disk location and Mach disk diameter showed good agreement at lower jet pressure ratios, with a tendency to slightly underpredict these parameters with increasing jet pressure ratio

Formation of plasma around a small meteoroid: 1. Kinetic theory

This article is a companion to Dimant and Oppenheim [2017] https://doi.org/10.1002/2017JA023963.This paper calculates the spatial distribution of the plasma responsible for radar head echoes by applying the kinetic theory developed in the companion paper. This results in a set of analytic expressions for the plasma density as a function of distance from the meteoroid. It shows that at distances less than a collisional mean free path from the meteoroid surface, the plasma density drops in proportion to 1/R where R is the distance from the meteoroid center; and, at distances much longer than the mean‐free‐path behind the meteoroid, the density diminishes at a rate proportional to 1/R2. The results of this paper should be used for modeling and analysis of radar head echoes.This work was supported by NSF grant AGS-1244842. (AGS-1244842 - NSF

Applying Publicly Available Contextual Factors to Predict Smoking Relapse in a National Sample

Background: The ecological fallacy is broadly understood, though its complimentary problem, the individualistic or atomistic fallacy, isless often considered. Multilevel models offer the statistical tools needed to avoid both errors by allowing simultaneous considerationof individual, contextual, and policy factors. This study applies such methods to smoking cessation data. Tobacco control is of particularconcern in Ohio where the adult smoking prevalence remains around 22%.Methods: Data from the 1,785 participants in the Technology Enhanced Quitline Study were used to test the theory that contextualfactors impact relapse rates and program effectiveness, employing a mixed-effects model to account for the nested nature of the datawhile testing for the relationship between contextual factors and relapse, controlling for individual characteristics.Results: No contextual factors or policy variables were significant predictors of smoking relapse in the sample, nor were any associated with the success of the intervention.Conclusions: While this work could not identify specific influences of contextual and policy factors on smoking outcomes in our sample, it demonstrates the feasibility of adding such predictors to future clinical trials. This project clearly does not rule out the possibility that contextual and policy factors may influence smoking even after controlling for individual characteristics, but does not provide strong evidence of such a link. It is possible that these negative findings may be due to geocoded mailing addresses being a poor proxy for relevant contextual factors, use of the wrong geographic unit of analysis (modifiable areal unit problem), or a lack of temporal resolution in contextual variables

Correlated defects, metal-insulator transition, and magnetic order in ferromagnetic semiconductors

The effect of disorder on transport and magnetization in ferromagnetic III-V semiconductors, in particular (Ga,Mn)As, is studied theoretically. We show that Coulomb-induced correlations of the defect positions are crucial for the transport and magnetic properties of these highly compensated materials. We employ Monte Carlo simulations to obtain the correlated defect distributions. Exact diagonalization gives reasonable results for the spectrum of valence-band holes and the metal-insulator transition only for correlated disorder. Finally, we show that the mean-field magnetization also depends crucially on defect correlations.Comment: 4 pages RevTeX4, 5 figures include

Multi-Layer Cyber-Physical Security and Resilience for Smart Grid

The smart grid is a large-scale complex system that integrates communication technologies with the physical layer operation of the energy systems. Security and resilience mechanisms by design are important to provide guarantee operations for the system. This chapter provides a layered perspective of the smart grid security and discusses game and decision theory as a tool to model the interactions among system components and the interaction between attackers and the system. We discuss game-theoretic applications and challenges in the design of cross-layer robust and resilient controller, secure network routing protocol at the data communication and networking layers, and the challenges of the information security at the management layer of the grid. The chapter will discuss the future directions of using game-theoretic tools in addressing multi-layer security issues in the smart grid.Comment: 16 page