The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

/pdf/the-environmental-protection-agency-3gx4opzrjm.pdf

The Environmental Protection Agency

Artificial neural networks (ANNs) constitute a class of flexible nonlinear models designed to mimic biological neural systems. In this entry, we introduce ANN using familiar econometric terminology and provide an overview of ANN modeling approach and its implementation methods. † Correspondence: Chung-Ming Kuan, Institute of Economics, Academia Sinica, 128 Academia Road, Sec. 2, Taipei 115, Taiwan; ckuan@econ.sinica.edu.tw. †† I would like to express my sincere gratitude to the editor, Professor Steven Durlauf, for his patience and constructive comments on early drafts of this entry. I also thank Shih-Hsun Hsu and Yu-Lieh Huang for very helpful suggestions. The remaining errors are all mine.

Artificial neural networks

Highway Capacity Manual改訂の動向--テイラ-教授の講演より

Dynamics of structures

Life-cycle assessment tool development for flexible pavement in-place recycling techniques

Near‐surface cracking is one of the predominant distress types in flexible pavements. The occurrence of near‐surface cracking, also sometimes referred to as top‐down cracking, has increased in recent years with the increased construction of relatively thick flexible pavements. However, understanding the mechanisms of near‐surface cracking and its integration into pavement design protocols remains a challenge. A mechanistic‐empirical approach requires a thorough understanding of the mechanisms of cracking on the surface or in the proximity of tires as well as an experimental characterization simulating field failure conditions. The analysis of this problem can become a very complex task due to multi‐axial stress states in the vicinity of tires. This study investigated the near‐surface response to non‐uniform tire contact stresses and analyzed the potential for occurrence of cracks near the surface in a typical relatively thick flexible pavement structure. The Generalized Finite Element Method (GFEM) was utilized to analyze the pavement structures in three‐dimensions (3‐D) considering the viscoelastic effects. This method provided a computational framework where arbitrary orientation of cracks in a finite element mesh is possible. The use of the GFEM in this problem was particularly intended for resolving the mixed mode fracture conditions which may emanate from the complex stress states in the vicinity of tires.

A Multi‐Scale Approach for Near‐Surface Pavement Cracking and Failure Mechanisms

/pdf/illinois-experience-using-quality-control-for-performance-fev2brm2k4.pdf

Illinois’ Experience Using Quality Control for Performance and Pay for Performance to Determine Pay for Hot-mix Asphalt

A passenger vehicle’s fuel-powered engine compensates for its dissipated energy, which is caused by road roughness. This paper presents an integrated vehicle–pavement approach and investigates the excess fuel consumption of a seven-degree-of-freedom (DOF) full-car model on rough pavements. In the approach, a nonstationary Laplace process is used to artificially generate road roughness profiles with consideration of local roughness variance and parallel roughness correlation. The proposed mechanistic approach quantifies the impact of road roughness and vehicle dynamic characteristics on excess fuel consumption. The study concluded that overlooking local roughness variance, an indicator of road roughness nonstationarity, may underestimate excess fuel consumption by 30%. Compared with a two-dimensional (2D) half-car model, a three-dimensional (3D) full-car model reduces computation error of excess fuel consumption by approximately 11%. For practical implementation, the extended roughness-speed-impact (ERSI) model (R2=98%) is developed to estimate roughness-induced energy dissipation of five two-axle vehicles. 

Mechanistic Excess Fuel Consumption of a 3D Passenger Vehicle on Rough Pavements

Closed-form expressions for calculating stresses and displacements of partially restrained concrete pavement caused by a linear temperature gradient are presented. Translational and rotatio...

Imad L. Al-Qadi

Papers

Life-cycle assessment tool development for flexible pavement in-place recycling techniques

A Multi‐Scale Approach for Near‐Surface Pavement Cracking and Failure Mechanisms

Illinois’ Experience Using Quality Control for Performance and Pay for Performance to Determine Pay for Hot-mix Asphalt

Mechanistic Excess Fuel Consumption of a 3D Passenger Vehicle on Rough Pavements

Closed-form solution for curling responses in rigid pavements