Progress in front propagation research

We review the progress in the field of front propagation in recent years. We survey many physical, biophysical and cross-disciplinary applications, including reduced-variable models of combustion flames, Reid's paradox of rapid forest range expansions, the European colonization of North America during the 19th century, the Neolithic transition in Europe from 13 000 to 5000 years ago, the description of subsistence boundaries, the formation of cultural boundaries, the spread of genetic mutations, theory and experiments on virus infections, models of cancer tumors, etc. Recent theoretical advances are unified in a single framework, encompassing very diverse systems such as those with biased random walks, distributed delays, sequential reaction and dispersion, cohabitation models, age structure and systems with several interacting species. Directions for future progress are outlined

Iowa Crop Progress & Condition, March 3, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

Update Regarding Disproportionate Minority Contact (DMC) Progress of Iowa Communities, December 1, 2015

The Iowa State Court Administrator’s Office (SCA) created the CASP Advisory Committee in October 2013 to develop a state plan addressing disproportionate minority contact (DMC) in the juvenile justice system. The planning was assisted with a discretionary grant awarded from the federal Office of Juvenile Justice and Delinquency Prevention (OJJDP).

Constructability in the Bridge Design Process, Progress Report, HR-320, 1990

Information concerning standard design practices and details for the Iowa Department of Transportation (IDOT) was provided to the research team. This was reviewed in detail so that the researchers would be familiar with the terminology and standard construction details. A comprehensive literature review was completed to gather information concerning constructability concepts applicable to bridges. It was determined that most of the literature deals with constructability as a general topic with only a limited amount of literature with specific concepts for bridge design and construction. Literature was also examined concerning the development of appropriate microcomputer databases. These activities represent completion of Task 1 as identified in the study.

Iowa Crop Progress & Condition, March 4, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

Iowa Crop Progress & Condition, March 5, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

Iowa Crop Progress & Condition, April 18, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

Iowa Crop Progress & Condition, April 11, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

The Effect of Deicing Salt on Aggregate Durability, Progress Report HR-266, 1985

The Iowa DOT has been using rapid freezing in air and thawing in water to evaluate coarse aggregate durability in concrete since 1962. Earlier research had shown that the aggregate pore system was a major factor in susceptibility to D-cracking rapid deterioration. There are cases were service records show rapid deterioration of concrete containing certain aggregates on heavily salted primary roads and relatively good performance with the same aggregate in secondary pavements with limited use of deicing salt. A five-cycle salt treatment of the coarse aggregate prior to durability testing has yielded durability factors that correlate with aggregate service records on heavily salted primary pavements. X-ray fluorescence analyses have shown that sulfur contents correlate well with aggregate durabilities with higher sulfur contents producing poor durability. Trial additives that affect the salt treatment durabilities would indicate that one factor in the rapid deterioration mechanism is an adverse chemical reaction. The objective· of the current research is to develop a simple method of determining aggregate susceptibility to salt related deterioration. This method of evaluation includes analyses of both the pore system and chemical composition.

Iowa Crop Progress & Condition, April 25, 2016

Report produced by the The Department of Agriculture and Land Stewardship, Climatology Bureau. Weather report released by the USDA National Agricultural Statistical Service. The report is released weekly from April through October. Formally titled: Iowa Crop and Weather Report

Image Analysis for the Characterization of Materials for Highway Construction : Phase I, Progress Report, HR-346, 1992

The major objective of this project is to evaluate image analysis for characterizing air voids in Portland cement contract (PCC) and asphalt concrete (AC) and aggregate gradation in asphalt concrete. Phase 1 of this project has concentrated on evaluation and refinement of sample preparation techniques, evaluation of methods and instruments for conducting image analysis, and finally, analysis and comparison of a select portion of samples. Preliminary results suggest a strong correlation between the results obtained from the linear traverse method and image analysis methods for determining percent air voids in concrete. Preliminary work with asphalt samples has shown that damage caused by a high vacuum of the conventional scanning electron microscope (SEM) may too disruptive. Alternative solutions have been explored, including confocal microscopy and low vacuum electron microscopy. Additionally, a conventional high vacuum SEM operating at a marginal operating vacuum may suffice.

A Progress Report on Treating Loess, Fine Sands and Soft Limestones with Liquid Binders, HR-20, 1954

Certain areas of Iowa abound in loess, others contain soft limestones that are readily and cheaply available, and a large portion of the state is underlaid with sand. None of these materials is considered suitable in present practices for use in all-weather road construction. The loess is too fine and too difficult to handle; the limestones are considered too soft, and some of the harder ones unsound for this use; the sands are not naturally of the desired gradation and do not lend themselves to blending into satisfactory gradations. The purpose of this project is, therefore, to study and develop means and to determine the feasibility of using these materials, loess, fine sand, and soft limestones, either separately or in combinations in conjunction with liquid binders to produce paving mixtures applicable for all-weather road construction. Also included in the project was the development of methods of processing any of these materials, if necessary, to make them suitable for the desired purpose

Evaluation of Microcracking and Chemical Deterioration in Concrete Pavements: Phase II, HR-358, Progress Report, 1995

The major objective of this research project is to investigate the chemistry and morphology of Portland cement concrete pavements in Iowa. The integrity of the various pavements is being ascertained based on the presence or absence of microcracks, the presence or absence of sulfate minerals, and the presence or absence of alkali-silica gel(s). Work is also being done on quantifying the air content of the concrete using image analysis techniques since this often appears to be directly related to the sulfate minerals that are commonly observed in the pavement cores.

Investigation of Rapid Thermal Analysis Procedures for Prediction of the Service Life of PCCP Carbonate Coarse Aggregate: Phase I, Progress Report, HR-337, 1992

The major objective of this research project is to utilize thermal analysis techniques in conjunction with x-ray analysis methods to identify and explain chemical reactions that promote aggregate related deterioration in Portland cement concrete. The first year of this project has been spent obtaining and analyzing limestone and dolomite samples that exhibit a wide range of field service performance. Most of the samples chosen for the study also had laboratory durability test information (ASTM C 666, method B) that was readily available. Preliminary test results indicate that a strong relationship exists between the average crystallite size of the limestone (calcite) specimens and their apparent decomposition temperatures as measured by thermogravimetric analysis. Also, premature weight loss in the thermogravimetric analysis tests appeared to be related to the apparent decomposition temperature of the various calcite test specimens.