Paul D. Ayers

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Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance,(More)
Sustainable use of military training lands requires understanding and prediction of the effects of military vehicles on vegetation. We examined the initial impacts of an 8-wheeled, light armored vehicle (LAV) on grassland vegetation at Fort Lewis, Washington. The LAV drove replicate spiral paths at two starting velocities, 10.3 and 5.1 m s(-1). The(More)
This study aimed at investigating the performance of multiple irrigation zoning scenarios on a 73 ha irrigated field located in west Tennessee along the Mississippi river. Different clustering methods, including k-means, ISODATA and Gaussian Mixture, were selected. In addition, a new zoning method, based on integer linear programming, was designed and(More)
The American Society of Agronomy A-2 Division, Military Land Use and Management, and the International Society for Terrain-Vehicle Systems cosponsored a symposium titled ‘‘Assessing the Impacts of Military Vehicle Traffic on Natural Areas’’. The symposium was held in Denver, CO on 4 November 2003. The objectives of this symposium were to characterize the(More)
In the context of off-road vehicle simulations, deformable terrain models mostly fall into three categories: simple visualization of an assumed terrain deformation, use of empirical relationships for the deformation, or finite/discrete element approaches for the terrain. A real-time vehicle dynamics simulation with a physics-based tire model (brush,(More)
Tractor overturns continue to be the leading cause of death on U.S. farms. While rollover protective structures (ROPS) are effective in preventing these fatalities, they are underutilized due to a number of barriers. Past programs in the U.S. and abroad have targeted this area of agricultural safety; however, a national program is not yet in place for U.S.(More)
In this study, the results from laboratory measurements of the devolatilization kinetics of switchgrass in a rapidly heated fixed bed reactor flushed with argon and operated at constant temperatures between 600 and 800°C was reported. Results indicate that switchgrass decomposes in two sequential stages during pyrolysis: stage I involves the evaporation and(More)
The goal of this research was to numerically predict the maximum lateral force acting on a mower rollover protective structure (ROPS) and the energy absorbed by the ROPS during a lateral continuous roll. A finite element (FE) model of the ROPS was developed using elastic and plastic theories including nonlinear relationships between stresses and strains in(More)
This testing aimed to determine the feasibility of using a kayak-mounted water quality collection system to measure the spatial distribution of water quality parameters (i.e. temperature, conductivity, pH, turbidity, and dissolved oxygen) in a given body of water. In addition to the water quality data collected by the spatial water quality analyzer, GPS and(More)