U.S. Farm Policy and the Variability of Commodity Prices and Farm Revenues, February 2000

A dynamic, three-commodity rational-expectations storage model is used to compare the impact of the Federal Agricultural Improvement and Reform (FAIR) Act of 1996 with a freemarket policy and with the agricultural policies that preceded the FAIR Act. Results support the hypothesis that the changes made when FAIR was enacted did not lead to permanent significant increases in the volatility of farm prices or revenues. An important finding is that the main economic impacts of the Pre-FAIR scenario, relative to the free-market regime were to transfer income to farmers and to substitute government storage for private storage in a way that did little to support prices or to stabilize farm incomes.

Report on Fly Ash Variability, MLR-81-2, 1981

The physical-chemical testing of fly ashes indicates that, under normal operating conditions, a low variability of results can be expected from a particular generating plant unit. However, unannounced changes in coal source and/or plant operations do occur and they may result in an ash with undesirable properties. Since these properties can be detected by physical-chemical testing, it is recommended that this testing be performed on a lot-by-lot basis when a plant is supplying fly ash to a construction project.

Case Study of Seasonal Variation in the Subgrade and Subbase Layers of Highway US 20, TR-516, 2008

Seasonal variations in ground temperature and moisture content influence the load carrying capacity of pavement subgrade layers. To improve pavement performance, pavement design guidelines require knowledge of environmental factors and subgrade stiffness relationships. As part of this study, in-ground instrumentation was installed in the pavement foundation layers of a newly constructed section along US Highway 20 near Fort Dodge, Iowa, to monitor the seasonal variations in temperature, frost depth, groundwater levels, and moisture regime. Dynamic cone penetrometer (DCP), nuclear gauge, and Clegg hammer tests were performed at 64 test points in a 6-ft x 6-ft grid pattern to characterize the subgrade stiffness properties (i.e., resilient modulus) prior to paving. The purpose of this paper is to present the field instrumentation results and the observed changes in soil properties due to seasonal environmental effects.