Relation Between First Arrival Time and Permeability in Self-Affine Fractures with Areas in Contact

We demonstrate that the first arrival time in dispersive processes in self-affine fractures are governed by the same length scale characterizing the fractures as that which controls their permeability. In one-dimensional channel flow this length scale is the aperture of the bottle neck, i.e., the region having the smallest aperture. In two dimensions, the concept of a bottle neck is generalized to that of a minimal path normal to the flow. The length scale is then the average aperture along this path. There is a linear relationship between the first arrival time and this length scale, even when there is strong overlap between the fracture surfaces creating areas with zero permeability. We express the first arrival time directly in terms of the permeability.Comment: EPL (2012)

Strategic targeting of cropland management using watershed modeling

Pushpa Tuppad1, Kyle R. Douglas-Mankin2, Kent A. McVay3(1. Texas AgriLife Research, 1500 Research Parkway, Suite B223, Texas A&M University, College Station, TX 77843, USA;2. Department of Biological & Agricultural Engineering, Kansas State University, Manhattan, KS 66506, USA;3. Railroad Highway, Southern Agricultural Research Center, Huntley, MT 59037, USA) Abstract: Effective water-quality protection should target Best Management Practices (BMPs) on watershed areas that contribute most to water-quality impairment instead of the typical voluntary implementation of practices, which may not be better than a random distribution of BMPs within a watershed.  This paper demonstrates a strategic approach for targeting watershed areas to maximize water-quality benefits from BMP implementation.  Almost half of the Smoky Hill River Watershed, Kansas, USA is cropland, a major sediment and nutrient source.  The impacts of reduced tillage, edge-of-field vegetative filter strips, and contoured-terraced practices on erosion and nutrient loads both overland and at the watershed outlet were evaluated using either random or targeted implementation, based on simulated average subbasin erosion rate.  The targeted approach was more effective in reducing sediment and nutrients, both at subbasin and watershed levels.  Annual average overland pollutant load reductions of 10% required BMP adoption on less than half the land area with targeted versus random placement.  The benefits of targeting were greater for initial increments of BMP adoption and decreased as implementation area increased.Keywords: targeting, conservation practices, erosion, SWAT modeling, watershed Citation: Pushpa Tuppad, Kyle R. Douglas-Mankin, Kent A. McVay.  Strategic targeting of cropland management using watershed modeling.  Agric Eng Int: CIGR Journal, 2010, 12(3): 12-24. &nbsp

Illinois River Levees: Sizing Up Their Impact on Flooding and Risk

The Illinois River is separated from its floodplain by a series of levees constructed and modified over time. These levees are subject to overtopping, but the frequency of the critical flood event varies from levee system to system and is not generally known. Investigations to consider reconnecting the river and its floodplain, building resilient river communities, and potentially diverting floods to agricultural land all require information about the land area, land use, structures, and population of each levee protected area. The objective of this research is to provide a comprehensive description of the leveed area along the Illinois River. Using the United States Army Corps of Engineers (USACE) National Levee Database (NLD), levee systems along the Illinois River were identified based on the availability of highly detailed topographic data. Each levee system was then analyzed in conjunction with the Upper Mississippi River System Flow Frequency Study (UMRSFFS) to determine the critical flood event expected to overtop each levee system. Based on this overtopping analysis, the areas of inundation landward of each levee system were studied using flooding depth and demographic and economic analysis to produce a representative summary of the risk for each levee system. Flooding depth grids were produced for each levee system representing the extent and depth of inundation expected when a levee system first overtops. Economic analysis included both investigation of average agricultural production per levee system using United States Department of Agriculture soil and crop data, and structural risk exposure using the Federal Emergency Management Agency Hazus-MH risk analysis software. The 35 levee systems studied have an annual chance of overtopping ranging from 6.9% to less than 0.2% (or 14 to >500 years on average). The average depth of flooding for a levee system due to overtopping ranges from 5.3 feet to 24.1 feet. Across all levee systems analyzed (206,000 acres), the average depth of flooding due to overtopping was 15.4 feet. This suggests that more than 3.1 million acre-feet of floodplain storage is currently disconnected from the Illinois River by the studied levees. The average gross economic value of crops grown within the levee systems included in this analysis was approximately 130 million dollars per year (based on crop years 2010–2012). Nearly 80% of the land area within the levee systems is devoted to the production of corn and soybeans. The remainder of the land area is evenly divided (about 5% each) among developed lands, open water, and pasture/hay. The population living within the Illinois River levee systems decreased approximately 1% between 2000 and 2010 to just over 9,500. More than 90% of the studied population lives within just 3 of the 35 studied levee systems. Although diversity increased slightly between 2000 and 2010, the population remains predominately white. Nearly 60% of the population is aged 18-64 with 26% less than 18 and 14% greater than 64. Hazards analysis using the Federal Emergency Management Agency Hazus-MH utility and overtopping projections produces an estimate of total exposure to the General Building Stock (GBS). These exposure estimates range, in terms of full building replacement value, from insignificant for small agricultural levees to more than 660 million dollars in developed urban areas. Expected damages due to overtopping range from insignificant to more than 155 million dollars. The total exposure to the GBS across all studied levee systems was more than $1.1 billion. Damages to the GBS due to overtopping of all levee systems is expected to be more than 265 million dollars.National Great Rivers Research and Education Centerpublished or submitted for publicationis peer reviewedOpe

Adaptive Polarization-Difference Imaging Algorithms for Through-the-Wall Microwave Imaging Scenarios

The preliminary results of application of Adaptive Polarization-Imaging Algorithm for Through-the-Wall Microwave Imaging problems are presented. Use of complete polarization information in the scattered field from the object together with the adaptation technique provides enhancement in detection of target movement

Adaptive Polarization Contrast Techniques for Through-Wall Microwave Imaging Applications

In this paper, we describe and utilize polarization contrast techniques of the adaptive polarization difference imaging algorithm and its transient modification for through-wall microwave imaging (TWMI) applications. Originally developed for optical imaging and sensing of polarization information in nature, this algorithm is modified to serve for target detection purposes in a through-wall environment. The proposed techniques exploit the polarization statistics of the observed scene for the detection and identification of changes within the scene and are not only capable of mitigating and substantially removing the wall effects but also useful in detecting motion, when conventional Doppler techniques are not applicable. Applications of the techniques to several TWMI scenarios including both homogeneous and periodic wall cases are presented

The role of researchers in disseminating evidence to public health practice settings: A cross-sectional study

BACKGROUND: Evidence-based public health interventions, which research has demonstrated offer the most promise for improving the population’s health, are not always utilized in practice settings. The extent to which dissemination from researchers to public health practice settings occurs is not widely understood. This study examines the extent to which public health researchers in the United States are disseminating their research findings to local and state public health departments. METHODS: In a 2012, nationwide study, an online questionnaire was administered to 266 researchers from the National Institutes of Health, the Centers for Disease Control and Prevention, and universities to determine dissemination practices. Logistic regression analyses were used to examine the association between dissemination to state and/or local health departments and respondent characteristics, facilitators, and barriers to dissemination. RESULTS: Slightly over half of the respondents (58%) disseminated their findings to local and/or state health departments. After adjusting for other respondent characteristics, respondents were more likely to disseminate their findings to health departments if they worked for a university Prevention Research Center or the Centers for Disease Control and Prevention, or received their degree more than 20 years ago. Those who had ever worked in a practice or policy setting, those who thought dissemination was important to their own research and/or to the work of their unit/department, and those who had expectations set by their employers and/or funding agencies were more likely to disseminate after adjusting for work place, graduate degree and/or fellowship in public health, and the year the highest academic degree was received. CONCLUSIONS: There is still room for improvement in strengthening dissemination ties between researchers and public health practice settings, and decreasing the barriers researchers face during the dissemination process. Researchers could better utilize national programs or workshops, knowledge brokers, or opportunities provided through academic institutions to become more proficient in dissemination practices

Contributor to the March Issue/Notes

Notes by Bernard F. Grainey, Warren A. Deahl, William B. Lawless, James F. McVay, and Thomas F. Halligan

Internal Friction and Vulnerability of Mixed Alkali Glasses

Based on a hopping model we show how the mixed alkali effect in glasses can be understood if only a small fraction c_V ofthe available sites for the mobile ions is vacant. In particular, we reproduce the peculiar behavior of the internal friction and the steep fall (''vulnerability'') of the mobility of the majority ion upon small replacements by the minority ion. The single and mixed alkali internal friction peaks are caused by ion-vacancy and ion-ion exchange processes. If c_V is small, they can become comparable in height even at small mixing ratios. The large vulnerability is explained by a trapping of vacancies induced by the minority ions. Reasonable choices of model parameters yield typical behaviors found in experiments.Comment: 4 pages, 4 figure

Towards a Practical Behavior Analytic Multitiered Consultation Model for Early Childhood Educators

Early childhood educators are in a critical position to support young children’s social-emotional, behavioral, and learning development, which can be accomplished through consistent use of evidence-based practices delivered in day-to-day interactions. However, early childhood educators may require support for implementing evidence-based practices. The purpose of this paper is to introduce a novel form of behavioral consultation for early childhood educators. Specifically, a behavior analytic multitiered consultation model in which implementation supports become increasingly more intensive is described. Rationale, implementation, evidence-base, and implications for practice and research are described. Finally, this paper concludes with an empirical case study to illustrate this model’s implementation. This paper is also meant to serve as a call-to-action for researchers and practitioners to replicate this consultation model