Vendor Ranking, March 22, 2012

Vendor Ranking for letting reports from the Iowa Department of Transportation.

Fertilizer Use by Crop at the Country Level (1990–2010)

We compute the fertilizer use in corn, cotton, soybeans, and rapeseed in the period from 1990 to 2010 for a set of selected countries. In each case, we present the consumption of nitrogen, phosphate, and potash by crop and by year, reporting both the fertilizer application rates (in kilograms per hectare) and the fertilizer consumption (in thousand metric tonnes). We allocate a country’s total nutrient consumption in a given year among competing crops based on publicly available statistics. The resulting allocation of fertilizer among crops is a function of the country’s nutrients total use, the country’s cropped areas, crop world prices, and crop- and country-specific fertilizer application rates for some years. In this report we show results on fertilizer consumption by crop for the top fertilizer consuming countries, and a downloadable MS Excel file “FertilizerDemandByCropData.xls” shows the complete set of results.

Macbride nature recreation area : hiking and cross-country ski trails, 1987.

This brochure contains information on the hiking and cross-country ski trails in the Macbride Nature Recreation Area located 15 minutes north of Iowa City in Johnson County.

Ranking of HMA Moisture Sensitivity Tests in Iowa, RB00-012, 2012

Several agencies specify AASHTO T283 as the primary test for field acceptance of moisture susceptibility in hot mix asphalt. When used in this application, logistical difficulties challenge its practicality, while repeatability is routinely scrutinized by contractors. An alternative test is needed which can effectively demonstrate the ability to screen mixtures based on expected performance. The ideal replacement can be validated with field performance, is repeatable, and allows for prompt reporting of results. Dynamic modulus, flow number, AASHTO T283, Hamburg wheel tracking device (HWTD), and the moisture induced sensitivity test (MIST) were performed on plant produced surface mixes in Iowa. Follow-up distress surveys were used to rank the mixes by their performance. The rankings indicate both the quantity of swelling from MIST conditioning and submersed flow number matched the performance ranking of all but one mixture. Hamburg testing parameters also appear effective, namely the stripping inflection point and the ratio between stripping slope and the creep slope. Dynamic modulus testing was ineffective, followed by AASHTO T283 and ratios produced from flow number results of conditioned samples.

All-American tradition : Iowa track and cross-country 1984-85

Contains information about the staff and athletes of the Iowa Hawkeyes Track and Field team for the 1984/85 academic school year. Also includes past year's results, team records, quick facts and schedule.